| 21. |
- Bråbäck, Lennart
(författare)
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Respiratory symptoms and atopic sensitization among school children in different settings around the Baltic Sea
- 1995
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis was to assess the prevalence of respiratory symptoms and atopic sensitization and related risk faCtors amo:Og school children in urban and rural areas of Sundsvall in Northern Sweden and urban areas of Konin in Poland and Tallinn and Tartu in Estonia. Ambient levels of N02 were similar in urban Sundsvall and Konin whereas levels of S02 and smoke were about 5 times higher in Konin than in Sundsvall. Children in Estonia and Poland had a lower standard of living and were more exposed to indoor air pollutants.Among 10 527 school children in Sundsvall aged 7-16 years the prevalence of asthma was 4% in 1985. No differences were seen between urban and rural Sundsvall. School absenteeism due to asthma was uncommon.The prevalence of positive skin prick tests in 642 school children (aged 10, 12 and 14 years) from urban and rural areas of Sundsvall was detem1ined in 1988. In this study, urban living was a risk factor for at least one positive skin prick test to pollen or animal dander, OR 1.83(95% Cl 1.26- 2.67). The increased risk was only demonstrated among children with atopic heredity. Passive monitoring of nitrogen dioxide in Sundsvall showed that urban children as compared with rural children were exposed to higher levels of NC>z (13 ;tglm3 and 7 ;tglm3, respectively). The children spent 90% of their time indoors. The most important source of exposure were the indoor skating arenas, where levels up to 8()(X) ;tglm3 were measured during 1-hour periods.Parental questionnaires, skin prick tests and serial peak flow measurements for a period of 2 weeks were used in the next study involving 2594 10-12 year old children from Sweden, Poland and Estonia. Respiratory symptoms were common whereas positive skin prick tests were uncommon in Poland and Estonia. The risk for positive skin prick test was decreased in Konin, OR 0.58 (95% CI 0.37- 0.91) but increased in urban Sundsvall, 1.67 (95% Cl 1.15- 2.42) (rural Sundsvall reference group). The odds ratios in Estonia were similar to Poland. Current maternal smoking had a strong dose-resp.:mse association with current coughing attacks but only in Eastern Europe. An inverse relationship was recorded between domestic crowding and sensitization, the risk of scnsitization increased as the number of persons in the household decreased (OR 0.58, 95% Cl 0.43- 0.77).The study suggests that factors related to domestic crowding protect against atopic sensitization in Estonia and Poland. In Sweden, by contrast, an increased standard of living with less crowding and less infections is associated with enhanced vulnerability to air pollutants andother adjuvant factors.
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| 22. |
- Cao, Jun
(författare)
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Characterization of antibodies against Helicobacter pylori
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- H. pylori is associated with the development of peptic ulcer, gastritis, and gastric cancer. Eradication of H. pylori by antibiotic treatment gives a healing of peptic ulcer and gastritis. However, due to drug resistance, there is a great need to explore alternative ways to eliminate bacterial infections.The goals of the present study were to characterize MAbs against surface components of H. pylori, and to investigate the functions of the bacterial surface components.Murine MAbs against surface components of H. pylori were produced by immunization of mice followed by hybridoma formation. One of the MAbs of the IgG1 subclass, was specific for both the spiral and coccoid forms of H. pylori. It reacted with a 28 kDa protein that was present in all the 5 strains of H. pylori tested. The MAb based indirect immunofluorescence microscopy on formalinfixed antral and corpus biopsy specimens from H. pylori associated gastritis patients showed that 9 of 9 antral and 5 of 6 corpus specimens harbored the coccoid form of H. pylori.An ScFv-phage which was derived from an M13 phage and mRNA of hybridomas secreting H. pylori MAbs, reacted with a 30 kDa H. pylori surface antigen. By means of immunofluorescence microscopy the phage was shown to bind to both the spiral and coccoid forms of the bacterium. In vitro the recombinant phage exhibited a bacteriocidal effect. When H. pylori was pretreated with the phage before oral inoculation of mice, the colonization of the mouse stomachs by the bacterium was significantly reduced. The parental MAbs were of the IgG1 subclass. The antigen was identified as a urease associated 30 kDa protein. The MAb decreased viability of the spiral form in broth culture, and reduced intracellular ATP in both spiral and coccoid forms of H. pylori.One MAb, 5D6 of the IgG2a subclass, was specific to a 56 kDa H. pylori protein. Immunofluorescence microscopy showed that this protein was located on the surface of both the spiral and coccoid forms of H. pylori. The MAb also bound to cells of the basal third of the oxyntic mucosa of rat stomachs and these cells were identified as gastric ECL cells. Sera of H. pylori-positive patients were investigated for ECL cell (auto)antibodies by means of ELISA using purified rat ECL cells as antigen. Ten (25%) of 40 sera from patients with atrophic corpus predominant gastritis scored positive; 2 (8%) of 26 sera from the patients with duodenal ulcer scored positive; only 1 serum (6%) from 16 healthy subjects was slightly positive. Four positive clones were obtained from a DNA hybridization of H. pylori and human gastric mucosa.The present results show that the MAb based immunochemistry provides a rapid and specific detection of both the spiral and coccoid forms. Binding of a urease associated 30 kDa protein by an ScFv-phage, or by its parental MAbs, decreased the viability of H. pylori. The protein may be considered as a candidate for a future vaccine. An antigenic mimicry which was found in surface of H. pylori and gastric ECL cells suggests a pathogenic role in gastritis.
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| 23. |
- Chatziarsenis, Marios
(författare)
-
New policies at Nosokomio Neapolis : introducing small areas research and development in a Cretan primary/hospital care setting
- 1999
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present thesis gives an account of the scheduled transformation of a combined Hospital and Primary Health Care institution, Nosokomio Neapolis, in a semi-rural community on Crete to an integrated population health research and development (R&D) centre by relatively minor organisational updatings and focused scientific studies with academic and political support and supervision. This process has engaged the whole local team, and the thesis is concerned with some of its bearing "Ariadne threads". First, the health systems perspective and framework of the Nosokomio Neapolis are described, including opportunities and scope of the directed, needs-and-outcome-oriented R&D undertaken also outside the focus of the present thesis, e.g. osteoporosis, cardiovascular diseases and accidents (I).Then, and new to Greece, three different and complementary lines are drawn concerning primary health care (PHC) quality assurance research in the three ages and with an epidemiological, risk factor and staff emphasis, respectively. The first of them is the primary prevention sector of immunisation in Cretan schoolchildren, where insufficient levels were found and measures of improvement implemented (II). The second concerns the determination of hepatitis A, B, and C markers and assessment of immunisation status in the Neapolis prison inmates and staff, and showing that both are high risk groups, where secondary and tertiary preventive measures are highly warranted (III). In the third age, research focused upon staff capacity regarding PHC physicians' level of knowledge and patterns of practices related to dementia in two European Regions; Crete, Greece and OstergOtland, Sweden. This is predominantly a tertiary preventive sector, where the care organisation is instrumentaL The study showed in the younger Greek PHC physicians a need for quality improvement, in particular in relation to Alzheimer's disease (IV).The final, fifth and sixth papers give an overview of the decisive step out to society, by a specially designed questionnaire, in order to achieve community involvement: a vital requirement for population participation and shar-ingjn the decentralised work towards Health For All by year 2000 and beyond (V - VI). The general conclusion of the thesis is that the new policies of small-areas action R&D in the community are both needed and relevant in the primary health care of Cretan and other Mediterranean areas.
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| 24. |
- Chen, Yun
(författare)
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Smooth muscle hypertrophy and the IGF-system
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Insulin-like growth factor-! (IGF-I) has both metabolic and mitogenic effects on smooth muscle cells (SMCs). The effects of IGF-I are modified by a group of binding proteins (IGFBPs). The present study was devoted to smooth muscle hypertrophy and the IGF-system in smooth muscle under different conditions. In urinary bladder, smooth muscle hypertrophy, initiated by partial outletobstruction, was associated with a transient increase in IGF-I mRNA, and pronounced, sustained increases oflGFBP-2 and IGFBP-4 mRNA, as well as increased protein contents of IGF-I and IGFBP-2. Regression of smooth muscle hypertrophy was associated with normalization of levels ofiGF-I, IGFBP-2 and IGFBP-4 mRNA. Expression of the IGF-I receptor did not change significantly. In portal vein, IGF-I mRNA and IGF-1 immunoreactivity were increased inhypertrophy induced by partialligation of the portal vein. Abdominal coarctation caused a rapid hypertensive response accompanied by an increased wet weight of aortic media. This was coincident with a progressive increase in aortic IGFBP-2 mRNA, about 10-fold after 14 days. The levels of IGFBP-4 mRNA in different muscle tissues and liver were decreased by diabetes and fasting, while IGFBP-2 mRNA was regulated in an organspecific 1nanner: with a sustained increase in liver and a decrease in aortic smooth muscle. Smooth muscle hypertrophy also occured in the urinary bladder of diabetic rats. DNA synthesis was increased and peaked at 2 days after induction of diabetes. DNA content per bladder wet weight was decreased by 7 days. Initially there was no changes in IGF-I mRNA, while IGFBP-2 mRNA and protein in the bladders were increased and peaked by 7 days. IGFBP-4 mRNA increased only on day 7. The changes of mRNA in bladder differed from that in liver and aorta, and suggested an early effect of stretching of the bladder due to diuresis, and later a contribution by the diabetic state. In cultured vascular SMCs, mechanical strain stimulated protein synthesis, but had little effect on DNA synthesis. However, mechanical strain potentiated the actions of IG:F'-1 and serum on both protein- and DNA synthesis, and influenced the effects of IGFBP-2. In conclusion, development of smooth muscle hypertrophy is associated with specific changes in IGF-I, IGFBP-2 and IGFBP-4, suggesting that the IGF-system may play a role in this process.
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| 25. |
- Chu, Ming
(författare)
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The role of endogenous hypercholecystokininemia and hypergastrinemia in growth and carcinogenesis of the exocrine pancreas
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The gut hormones cholecystokinin (CCK) and gastrin are phylogeneticallyand structurally related. Under normal conditions, CCK regulates growth of the exocrine pancreas and gastrin growth of the oxyntic mucosa of the stomach. The effects of chronically increased endogenous secretion ofCCK or gastrin on pancreatic growth and carcinogenesis are not fully investigated. This thesis deals with such studies in rats and hamsters, using pancreaticobiliary diversion (PBD) to accomplish endogenous hypercholecystokininemia and gastric fundectomy to accomplish endogenous hypergastrinemia. PBD caused an immediate and persistent increase in the plasma CCKconcentration without affecting the plasma gastrin concentration. In hamsters, PBD induced an initial hyperplasia (increased [3H]-thymidine labeling index) of acinar cells followed by a persistent hypertrophy (increased weight, protein content, and DNA content) of the pancreas. No such changes were found in PBD operated hamsters receiving a CCK-A receptor antagonist. Longterm (14 months) PBD in rats lead to an increased fraction of aneuploid cells (DNA flow cytometry) in pancreatic tissue, and development of putative pre-neoplastic lesions (PPL) (acidophilic atypical acinar cell foci) and adenoma of the pancreas. No PPL or neoplasia were observed after longterm ( 8 months) PBD in hamsters. When rats were given a pancreatic carcinogen (azaserine), addition of PBD caused an increase in the fraction of aneuploid cells and in the volume fraction and cellular proliferation ( [3H]-thymidine labeling index) of the PPL. When hamsters were given a panceatic carcinogen (N-nitrosobis(2-oxopropyl)amine) (BOP), addition of PBD caused an increase in the incidence of PPL (ductal complexes) and ductal carcinoma in situ was observed. Furthermore, PBD caused an increase in the proliferative activity of the PPL. No increased proliferation in the PPL was seen in PBD operated animals receiving a CCK-A receptor antagonist. Gastric fundectomy caused an immediate and persistent increase in theplasma gastrin concentration without affecting the plasma CCK concentration. In hamsters, fundectomy induced an initial hyperplasia of acinar, ductal, and centroacinar cells followed by a persistent hypertrophy of the pancreas. No such changes were found in fundectomized animals receiving a CCK-B/gastrin receptor antagonist. Longterm (14 months) fundectomy in rats lead to an increase in the fraction of aneuploid cells in pancreatic tissue and development of PPL, but not neoplasia. No PPL or neoplasia were observed after long-standing ( 8 months) fundectomy in hamsters. When rats were given a pancreatic carcinogen (azaserine), addition of fundectomy lead to an increase in the fraction of aneuploid cells and an increase in the volumefraction, but not the proliferative activity, of the PPL. When hamsters weregiven a panceatic carcinogen (BOP), addition of fundectomy did not cause any significant change in the incidence or proliferative activity of PPL, and no neoplasia was observed. In conclusion, PBD induced persistent hypercholecystokininemia andfundectomy persistent hypergastrinemia, both of which induced exocrine tissue hyperplasia leading to persistent hypertrophy of the pancreas in rats and hamsters. The effects of PBD and fundectomy seemed to be mediated by CCK and gastrin, since they were blocked by simultaneous administration of a specific CCK-A and CCK-B/gastrin receptor antagonist, respectively. In longterm studies, both procedures caused development of PPL of the pancreas in rats but not in hamsters. In both rats and hamsters treated with a pancreatic carcinogen, addition of PBD enhanced the development of PPL. In rats, but not in hamsters, addition of fundectomy to carcinogen treatment also enhanced the development of PPL. Overall, the trophic as well as the promotive effects were significantly more pronounced after PBD than after fundectomy. In both rats and hamsters, pancreatic neoplasia was observed after PBD, but not after fundectomy.
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| 26. |
- Dabrosin, Charlotta
(författare)
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Effects of sex steroids on normal human breast : studies in vivo using microdialysis and in vitro in cell culture
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prolonged exposure to sex steroids may constitute a risk factor for the development of breast cancer. The biological mechanisms involved in breast carcinogenesis are not well understood.Basic knowledge of sex steroid effects on the normal human breast is still limited, one reason being the lack of an available in vivo technique for investigations of breast tissue metabolism.In this study, the microdialysis technique was developed and evaluated as a method for measurements of tissue-specific concentrations of amino acids, lactate, pyruvate and glutathione in normal human breast tissue during the menstrual cycle. The technique was successfully applied to breast tissue and it was observed that the concentrations of several amino acids as well as glutathione changed during the menstrual cycle. Oxidative damage to cells is one of the mechanisms which may be involved in the development of breast cancer. Normal aerobic metabolism generates potentially dangerous oxidants which are controlled by a variety of antioxidant systems. The exact regulatory mechanisms of these systems are not yet fully understood. We studied the effects of estradiol and progesterone on antioxidative activity in normal human breast tissue, in vivo with the microdialysis technique, and in vitro using normal human breast epithelial cells in culture. The in vivo levels of the antioxidant glutathione were measured early and late in the menstrual cycle in breast tissue and subcutaneous fat. The glutathione levels were higher late in the menstrual cycle in both tissues, when the serum levels of estradiol and progesterone were high. In vitro, breast epithelium exposed to estradiol and progesterone exhibited decreased activity of the antioxidative enzymes catalase and glutathione reductase, whereas the activity of glutathione peroxidase tended to increase compared with cells grown in medium without added sex hormones. The vulnerability to oxidative stress, induced by hydrogen peroxide, increased in cells grown with estradiol and progesterone present in the media. α-Tocopherol, and α-tocopherol in combination with ascorbic acid, but not ascorbic acid alone, protected from cell death induced by hydrogen peroxide. This effect was not dependent on estradiol and progesterone exposure.In conclusion, the data suggest an effect of estradiol and progesterone on antioxidative activity in normal human breast tissue both in vivo and in vitro.Microdialysis will be a useful tool in future research of these and other aspects concerning human breast tissue.
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| 27. |
- Dabrosin-Söderholm, Johan, 1958-
(författare)
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Epithelial barrier dysfunction in ileal Crohn's disease
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The study aimed at investigating the intestinal barrier in Crohn's disease, with special reference to epithelial responses to luminal stimuli, and to permeation of proteins.Ileal mucosa from patients undergoing intestinal resection was studied in vitro in Ussing chambers. Intestinal permeability was also studied in vivo, by oral load of lactulose and mannitol.The Ussing chamber was evaluated for intestinal barrier studies. Normal ileal mucosa from patients with colon cancer was subjected to long-term experiments, and investigated in regard to various viability parameters. Mucosal permeability, structural integrity and metabolism were maintained for 90 minutes, and specimens with poor viability were detected by a low transepithelial potential difference. In rat ileal mucosa, luminal sodium caprate, a constituent of milk fat, induced dilatation of the tight junctions as visualised by electron microscopy, and a reversible increase in tight junction permeability. The findings indicate that the Ussing chamber is suitable for studies of the intestinal barrier, including tight junction regulation, provided that experiments are monitored by measurements of transepithelial potential difference and are limited in time.In vitro studies of human ileal mucosa showed that luminal sodium caprate caused uncoupling of oxidative phosphorylation, as shown by a fall in epithelial ATP contents, and mitochondrial swelling seen by electron microscopy, paralleled by an increased permeability. Non-inflamed Crohn's disease specimens had an exaggerated permeability increase and an augmented fall in transepithelial electrical resistance. Confocal microscopy revealed rearrangements of perijunctional filamentous actin, causing dilatation of the tight junctions. In Crohn's disease, a more pronounced reorganisation of actin filaments was seen, suggesting the tight junctions to be hyperreactive to luminal stimuli due to a disturbed cytoskeletal regulation.In vivo, an increased intestinal permeability was induced by ingestion of acetylsalicylic acid. One third of both Crohn's disease patients and their first-degree relatives showed an augmented permeability increase, whereas spouses were equal to controls, suggesting a genetically determined vulnerability of the intestinal barrier.In vitro, non-inflamed ileum from Crohn's disease patients had an increased permeation of ovalbumin. Confocal microscopy suggested this to be caused by an augmented transcytosis, a previously unrecognised defect in the epithelial barrier in Crohn's disease, with a subsequent exposure of antigenic proteins to the subepithelial immunocytes.The Crohn's disease patients without residual inflammation after surgery were followed with endoscopy within twelve months, and all revealed recurrent ileal inflammation.The study indicates a perturbed intestinal barrier in Crohn's disease, possibly genetically determined. The impaired barrier function is demonstrated both by an augmented epithelial transcytosis and by hyperreactive tight junctions. The epithelial barrier dysfunction precedes the recurrent intestinal inflammation in ileal Crohn's disease. The findings suggest an interplay between an impaired epithelial barrier and luminal factors in the initiation of intestinal inflammation.
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| 28. |
- Dimberg, Jan
(författare)
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Studies on expression and regulation of phospholipase A2 and cyclooxygenase 2 in gastrointestinal tissues with special reference to colorectal cancer
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The phospholipases A2 (PLA2s) are phospholipid hydrolyzing enzymes that in mammalian cells exist in several different isoform including cytosolic PLA2 (cPLA2), group I PLA2 (PLA2-I) and group II PLA2 (PLA2-ll). PLA2 is involved in production of inflammatory mediators, membrane remodelling, digestive functions and stimulation of prolifemtion. In addition. PLA2 supplies cyclooxygenase COX-1 and COX-2 with arachidonic acid for production of eicosanoids.Increased COX-2 expression and high concentrations of prostaglandins have been found in human colorectal adenocarcinomas and in rat colonic twnours. Studies implicate that there is a link between the tumourigenic effect of the tumour suppressor gene adenomatous polyposis coli (APC) and COX-2 up-regulation in mouse intestinal neoplasms. Mutations of the human APC gene are frequent in both sporadic and familial colorectal cancer and result in activation of p-catenin!T cell factor-4 (Tcf-4) mediated transcription of target genes which may contribute to colorectal tumourigenesis.The ontogenic development of rat gastrointestinal PLA2-I and PLA2-II and the influence of the exogenous glucocorticoid cortisone acetate were studied. The ontogeny of rat glandular stomach PLA2-I and PLA2-II gene expression is similar and seems to follow the general postnatal development of the gastrointestinal tract PLA2-II gene expression is different in the glandular stomach compared to ileum and forestomach during the neonatal period. Administration of the cortisone acetate, during the neonatal period, induced PLA2-I and PLA2-II gene expression in glandular stomach and ileum, respectively, au effect that may be related to maturation of the gastrointestinal tract.Gene expression of PLA2-II, cPLA2 and COX-2, protein levels of COX-2 and mutational analysis of APC were investigated in human colorectal tumours. COX-2 was dramatically up-regulated in tumours located in rectum and associated with the presence of APC mutations. Tcf-4 consensus sequences found in the COX-2 promoter were activated but APC/P-catenin/fcf-4 pathway may partly be involved in transcriptional regulation of the COX-2 gene. Neither induction of PLA2-II nor correlation in gene expression between cPLA2 and COX-2 were observed. 'These observations imply that other enzymes than PLA2 contribute to generate arachidonic acid for COX-2 mediated eicosanoid metabolism aud that PLA2-II seems to play a minor or no role in hllltlan colorectal cancer.
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| 29. |
- Dizdar (Dizdar Segrell), Nil
(författare)
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Microdialysis as a Tool in Studies of L-Dopa and Metabolites in Malignant Melanoma and Parkinson’s Disease
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A model with human melanoma xenografts transplanted to athymic mice has been adopted for in vivo studies of 5-S-cysteinyldopa (an intermediate pigment metabolite), glutathione, and cysteine. L-Dopa is an intermediate metabolite in pigment formation and is also important in the treatment of Parkinson's disease, and therefore 1 have also studied the pharmacokinetics of this compound.We were first to describe in vivo microdialysis in melanoma tissue and showed that dialysis membranes of cuprophane or polyamide are suitable for studies of interstitial 5-S-cysteinyldopa and selected thiols. Analytical procedures were also improved for quantitation of 5-S-cysteinyldopa, L-dopa, glutathione, cysteine, and N-acetylcysteine (NAC). In the melanoma xenografts the interstitial concentration of 5-S-cysteinyldopa reflected the high intracellular production of this intermediate metabolite. For in vivo manipulation of glutathione in the melanoma tissue we gave intraperitoneal injection of buthionine sulphoximine to the animals and thus reduced the glutathione concentrations substantially. We showed that restitution of glutathione in melanoma tissue occurs spontaneously and is not much improved by treatment with the cysteine deliverers NAC and L-2-oxothiazolidine-4-carboxylate (OTC). 5-S-Cysteinyldopa was not substantially affected by great variations in glutathione concentrations. Transport of NAC from intraperitoneal injection to melanoma tissue occurred rapidly and deacetylation to cysteine in vivo could be detected soon after NAC injection. In vivo formation of cysteine was slower from OTC than from NAC.Pharmacokinetic studies of L-dopa in human subjects indicated a slight to moderate protein binding. Plasma free L-dopa had similar elimination T½ as interstitial L-dopa, but in some cases the elimination of total L-dopa was slower. Difficulties in intestinal absorption of L-dopa were revealed by microdialysis in blood and subcutaneous tissue. Studies showed that this was due to delayed emptying of the stomach. L-Dopa intake increased 5-S-cysteinyldopa concentrations in blood within 30 min in patients with Parkinson's disease and a history of melanoma. No melanoma activation occurred during long-term treatment with L-dopa.Microdialysis is thus a safe and easily applied method for in vivo studies of both pigment metabolites from human melanoma tissue transplanted to nude mice and for pharmacokinetic studies of L-dopa.
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| 30. |
- Druid, Henrik
(författare)
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Experimental acute ischemic renal failure and anticoagulation
- 1998
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on experimental studies on acute renal failure (ARF) in rats. The model employed is that of renal artery clamping, which causes a standardized, ischemic trauma to the kidney. The proximate objective of the investigations was to study iflocal coagulation in the kidney may be induced by a pure ischemic trauma, and whether such a coagulation could be of importance for the development of ARF in this experimental model.The content of isotope-labeled fibrinogen and albumin was determined in postischemic kidneys and controls. After 60rnin of unilateral ischemia, the fibrin(ogen)/degradation products (FIB) and albumin content of the kidney increased rapidly and significantly, approximately averaging 200% of controls. The total kidney weight increased only to 130% of controls. Pretreatment with heparin in a dose of 2000 IU/kg BW, markedly attenuated the increase in kidney weight and content of FIB and albumin.Pretreatment with a lower dose of heparin, 400 IU!kg BW, and warfarin (given intraperitoneally 24 h before the experiment) produced a similar reduction of these parameters, whereas pretreatment with a heparin analog, devoid of anticoagulant effect, did not.In post-ischemic kidneys, scanning electron microscopy (SEM) of cautiously handled freezedried tissue revealed granular and fibrillary material in the tubules and in Bowman's space, at some locations displaying prominent network patterns. Immunofluorescence against FIB showed immunoreactive material in vasa recta, the peritubular capillaries, Bowman's space and in the tubules. By transmission electron microscopy (TEM), fibrin strands lacking periodicity were seen. As compared to controls, the postischemic kidneys generally showed a marked dilatation of Bowman's capsule. No fibrin deposition was seen in heparin pretreated animals.To determine if anticoagulation exerts the described effects by prevention of tubular obstructions or by attenuation of increased glomerular permeability, morphometry of glomeruli was performed by light microscopy and TEM Postischemic kidneys from rats pretreated with saline showed a marked widening of Bowman's space, most likely due to tubular obstruction, whereas Bowman's space width in anticoagulated rats did not differ from controls. Structural changes of the podocyte foot processes as a marker of increased macromolecular permeability were severe in both saline pretreated and anticoagulated kidneys.Glomerular filtration rate fell to 6% of controls after 40 min of ischemia. Warfarin-pretreatment attenuated this decrease significantly. Urinary protein excretion increased in both salinepretreated and anticoagulated rats. The excretion of FIB was significantly increased in warfarinpretreated rats, consistent with the previous observation of an attenuation of FIB content of postischemic kidneys by anticoagulation. This result thus suggests that warfarin did not prevent macromolecular sieving, but reduced the formation of protein-containing tubular casts.In summary, these studies show that a pure ischemic injury to the kidney results in a local coagulation in the kidney, most prominently within Bowman's space and in the tubules. It is suggested that the increased glomerular permeability to macromolecules causes sieving of fibrinogen, which may precipitate in Bowman's space and tubuli and promote the development of tubular obstructions.
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