| 11. |
- Ghassemifar, M. Reza
(författare)
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Connective tissue contraction in wound healing : An experimental study in vivo and in vitro
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Contraction of connective tissue is an important part of tissue repair that reduces the wound space and helps to decrease the formation of scar tissue, both of which are needed to restore tissue integrity. In the present study, certain cellular mechanisms that are active during connective tissue contraction were assessed and the influence of transforming growth factor-.131 on these mechanisms was evaluated in normal rat and protracted mouse contraction. A new double-embedding technique for sectioning of thin tissue membranes was developed and a multisequence template was constructed that allowed quantification of a number of target mRNAs [:rGF -.131, TGF -.13 type li receptor, alpha-SM actin and .13-actin) from 0.5-2 11g of total RNA. The fibroblast-populated collagen lattice model (FPCL) was used for studies of contraction in vitro, and, in vivo, the perforated mesentery models of rat and mouse were employed. Fourier transformation image analysis was used to assess the orientation of actin in mesenteric wound fibroblasts. Studies in vitro showed that rat, but not mouse, macrophage conditioned medium stimulated contraction of FPCL in serum free medium and that supplementation with serum impaired FPCL contraction. In vivo, rat wound fibroblasts expressed alpha-SM actin during closure of perforations, as shown by in situ hybridization. Using quantitative RT-PCR, it was shown that the expression of alphaSM actin was increased lOO-fold in wounded as compared to unwounded tissue, and that TGF -.131, while stimulating closure of perforations, also increased alpha-SM actin mRNA 4-5 fold inwounded tissue of both rat and mouse. However, the expression of alpha-SM actin was considerably higher in the wounded mesenteriesof rats than in those of mice. TGF -.131 was expressed by normal, unstimulated peritoneal macrophages and, for the first time, shown tobe downregulated in activated, wound macrophages in both rat and mouse. The orientation of actin bundles in wound fibroblasts wasderanged in impaired healing in zinc deficiency but unaffected by TGF -.131 in stimulated contrition. In conclusion, the results have shed further light on various cellular activities during connective tissue contraction. A number of differences were found between rats and mice that help to clarify the mechanism of protracted healing in the mouse. The complex interaction of these mechanisms await to be further elucidated.
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| 12. |
- Gottvall, Tomas
(författare)
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Red cell alloimmunization during pregnancy
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We have evaluated a new screening program to detect red cell alloimmunization during pregnancy that was introduced in the south-east region of Sweden in 1981. The screening program is based on two antibody tests at 25 and 35 gestational weeks for all pregnant women regardless of maternal Rh(D) status. During the period 1983-89, all pregnant women in the region were tested (78,300) and 0.37% were found to exhibit red cell alloimmunization. Antibodies with anti-D specificity were the most common (34%), followed hy anti-E (24%), anti-Kell (17%) and anti-c (11%). These immunizations also caused the most severe cases of hemolytic disease of the newborns. The screening program was efficient since no newborn subjected to exchange transfusion was overlooked. Most of the new immunizations occurred among the Rh(D) positive women (63%). However, the cost of detecting a few severely affected fetuses among the Rh(D) positive women is high. In this group of pregnancies, it seems sufficient with only one antibody screening test, if done at 25 gestational weeks.The standard variables commonly used to predict fetal hemolytic disease (FHD) were studied. A low antibody titer level in maternal sernm (≤32) accurately predicted unaffected fetuses. When moderately elevated antibody titer levels (≥64) were present, complementary test variables were needed for a relaihle prediction of FHD. In Rh(D) alloimmunizations, the anti-D concentration in maternal serum, with a cut-off level of 0.7 µg/mL, was the best complementary variable. We could accurately distinguish a low-risk group from a high-risk group of pregnancies. Measurement of the bilirubin content in aruniotic fluid (ΔOD450) did not give any further information of relevance in predicting PHD.High-dose intravenous immunoglobulin (IVIG) treatment appeared to prevent a further deterioration of PHD when a moderate to severe FHD was present (B-hemoglobin concentration between 70-100 g/L). This was observed as a stabilized fetal hemoglobin concentration and an increased fetal anti-D concentration, both interpreted as an effect of a decreased erythrophagocytosis in the fetal reticuloendothelial system.We propose a flowchart with guidelines for the management of pregnancies complicated by red cell alloimmunization.
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| 13. |
- Grönroos, Eva
(författare)
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Leukotriene D4-induced signal transduction in human epithelial cells
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Although the structures of the cysteinyl-leukotrienes have been known for almost twenty years, and their biological effects for almost sixty years, very little is known about the signaling propenies of these compounds. The aim of the present research was to further elucidate the components that are involved in the signaling mechanisms of leukotriene D4 (L TD4) in a human epithelial cell line. Stimulation with LTD4 was found to induce the mobilization of intracellular calcium as well as the influx of calcium through the plasma membrane. Although the LTD4 receptor probably belongs to the seven-transmembrane-spanning G-protein-coupled receptors, phospholipase Cyt is tyrosine phosphorylated and translocated to the plasma membrane upon stimulation with L1D4. The unknown, genistein-insensitive kinase responsible for this effect is directly or indirectly activated by a monomericG-protein that probably belongs to the Rho fantily. We were unable to see any direct association between a Rho protein and phospholipase Cy1, instead we found that the monomeric G-protein Rapl associates with phospholipase Cyt in unstimulated cells. After stimulation the content of Rapl increases in the plasma membrane,simultaneously as it dissociates from phospholipase Cy1 in a manner dependent on protein kinase A. The L1D4-induced calcium influx is mediated through a pertussistoxin- sensitive 0-protein. Engagement of the L TD4 receptor also induces a rapid increase in cAMP and the activation of a genistein-sensitive tyrosine kinase. Both of these events are necessary for the LTD4-induced calcium influx. The increase in cAMP probably precedes the activation of the tyrosine kinase, since preincubation with Rp-cAMPS, which inhibits protein kinase A, interferes with the L 1D4-induced tyrosine phosphorylation. The identities of the kinases involved in the calcium mobilization and influx are still unresolved. Taken together, our findings show that L TD4 stimulation of the intestinal epithelial cell line INT 407 results in the activation of at least three different G-proteins and two kinases of importance for the regulation of cytosolic calcium levels in these cells.
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| 14. |
- Gullberg, Mats, 1953-
(författare)
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Health care professionals' self description
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present thesis was to survey and analyse professional self of health care professionals, focusing on perceptions of self, and on their attitudes towards aspects of sense of responsibility.Studies were accomplished with quantitative techniques using questionnaires and/or instruments. A total of 803 respondents was included, and the first study (I) presented the development of the PSDF and comprised 30 registered nurses. The next study (II) examined results from 332 medical laboratory technologists who answered the PSDF. In the third study (III) 68 occupational therapists responded to the PSDF. The fourth study (IV) was a six-year follow-up of 43 registered nurses from the beginning of their training to three years after graduation, and they responded to the PSDF, the SRF and to the Form for ranked sources of encouragement. The fifth study (V) comprised four professional groups from a university hospital in Sweden (physicians, physiotherapists, registered nurses and enrolled nurses), and 312 responded to the set of forms (the PSDF, the SRF, and the Form for ranked sources of encouragement).The main theoretical approach was based on symbolic interactionism, where the self is a significant notion. Concepts on attitude, sense of responsibility and encouragement were important.The results showed that there are components of self description that is 'specific to one professional group, but also components that uncover similarities. Three important components of professional self were outlined; professional conduct, work ability and empathy. Important issues were also encouragement for work done, which influences the professional self, and that the positive attitudes to sense of responsibility showed similarities with characteristics of professional self.In conclusion, two propositions were addressed: that professionals' self description is composed of three meaningful dimensions; professional conduct, work ability and empathy, and that the professional self can be improved throughdevelopment of intrinsic attitudes and behaviours.
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| 15. |
- Hallböök, Olof, 1954-
(författare)
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Colonic pouch anastomosis after rectal excision for cancer
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Anastomoses at the level of the pelvic floor will become increasingly more common in rectal cancer surgery when total mesorectal excision is used as a standard procedure to obtain local mdicality. A consequence of such low anastomoses is increased risk of healing disturbances and poor distal bowel function, The aim of this thesis was to focus on reconstruction after total mesorectal excision. A randomized trial comparing the conventional straight anastomosis (n=52) and the colonic pouch anastomosis (n=45) showed that the pouch patients had fewer bowel movements per 24 hours, less nocturnal evacuations, urgency and incontinence at one year after surgery. The superiority of colonic pouches could not, however, be verified by a general quality of life instrument, the Nottingham Health Profile. One disadvantage with the pouch reconstruction was that some patients experienced difficult evacuation. The trial also showed less anastomotic leakage in the pouches. This may partly be attributable to the concept of side-to-end reconstruction, which had a better preserved blood flow at the site of anastomosis than the straight (end-to-end) alternative, as shown by intraoperative laser Doppler flowmetry. In the search for specific mediators of the functional adaption after a restorative rectal excision two gut peptides, peptide YY and enteroglucagon, were sequentially measured in both plasma and neorectal mucosa after surgery. No major changes occurred. Manovolumetric investigation of the rectal substitute showed that construction of colonic pouches restores volume, improves compliance and sensory function compared with straight anastomoses. Compared with healthy rectum, pouches exhibit sensory deficits and decreased compliance despite adequate volume, factors which may partly explain why some pouch patients experience impaired evacuation. Maximum volume of the pouches was positively correlated with degree of evacuation difficulty. This association was verified by logistic regression with adjustment for confounding factors. Obviously colonic pouches cannot have the unique reservoir function of the healthy rectum. However, in-spite of physiological changes regarding sensory function, compliance, motility and reflex inhibition, patients having a colonic pouch anastomosis will usually experience satisfactory clinical bowel function.
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| 16. |
- Halldorsdottir, Sigiridur
(författare)
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Caring and uncaring encounters in nursing and health care : Developing a theory
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The general aim of the present thesis was to develop a theory on caring and uncaring encounters within nursing and health care from the patient's perspective.Results of an analysis of two phenomenological studies (paper I), as well as research findings from five other phenomenological studies (papers II-VI), were used to develop the theory.Caring and uncaring can be conceptualized on a continuum symbolizing five basic modes of being with another, which, for example, involves a neutral mode of being with another, where the individual is perceived as neither caring nor uncanng.There are two major metaphors in the theory, that of the bridge, symbolizing the openness in communication and the connectedness experienced by the recipient of care in an encounter perceived as caring. The other metaphor is the wall, which symbolizes negative or no communication, detachment and lack of a caring connection, experienced by the recipient in an encounter perceived as uncaring.In the theory the importance of professional caring within nursing and health care is proposed, essentially involving competence, caring, and connection. The above-mentioned 'bridge' is developed through mutual trust and the development of a connection between the professional and the recipient. This connection is a combination of professional intimacy and a comfortable distance of respect and compassion -- professional distance. On the other hand, uncaring involves perceived indifference and incompetence, creating distrust, disconnection and the above-mentioned 'wall' of negative or no communication.The recipient of professional caring is influenced positively. Theconsequences, which are an increased sense of well-being and health, can be summarized as empowerment. Uncaring, however, has the negative consequences of decreased sense of well-being and health, which can be summarized as discouragement. Empowerment and discouragement in this context are defined as subjective experiences of the recipients of care.The importance of seeing the recipient in his or her inner and outer contexts is emphasized in the theory. The inner context involves perceived needs, expectations, previous experiences and sense of self, which in the perspective of the recipient of nursing can be summarized as both a sense of vulnerability and the need for professional caring. The perceived hospital environment comprises the recipient's outer context.It is concluded that nurses and other health professionals can, by theirprofessional caring or lack of it, be powerful sources of empowerment ordiscouragement to those whom they are pledged to serve.
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| 17. |
- Helmrot, Ebba
(författare)
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Systematic analysis of a radiological diagnostic system : A method for application in the effective use of x-rays in intraoral radiology
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The effective use of an imaging system in diagnostic radiology implies an optimisation process. This demands knowledge and relevant descriptions of the various components, the X -ray units, the objects and receptors. Thus, in this work photon energy spectra have been measured, phantomsresembling human tissue constructed and receptor characteristics investigated. Essential image quality parameters (contrast, signal-to-noise ratio) and a radiation risk indicator for the patient (energyimparted) have been defined and their variation with photon energy spectrum determined for different objects and details. Results are presented as basic infonnation to be used by radiologists in collaboration with physicists in optimising examinations according to the patient and the particular diagnostic task. For intraoral radiology with Ultra-speed fihn, it is shown that to achieve equalised radiographic contrasts of an ivory wedge, kV-settings have to be decreased by 5-8 kV when single pulse X-ray generators are replaced by high-frequency constant potential ones. When imaging the ivory wedge in a PMMA phantom with Ektaspeed and Ultra-speed films at equal contrast, 7-9 kV lower kV-setting must be used with the Ektaspeed film. Ektaspeed film then gives a 35-40% decrease in the energy imparted tothe patient which can be compared to 45-55% decrease observed if the loss of contrast is not compensated for by lowering the kV-setting. Comparison of the contrasts of both films shows that Ultra-speed has higher contrast than Ektaspeed, but the latter has a wider dynamic range and higher values of base and fog optical densities, which contribute to its lower contrast at low optical densities. The radiographic contrast of details in the object is the product of object and film contrast. Objectcontrast depends on photon energy and is the same for both films. The energy imparted to the patient is calculated using conversion factors derived in this work. To simulate the large variety of anatomical structures encountered in intraoral radiology, a multimaterial compound hard tissue phantom was constructed. The constituent elements and their fractions by weight were carefully determined so as to allow computational methods to be used tocomplement experimental data. Different types of imaging system imply different optimal photon energy spectra. Strategies of optimising photon energy spectra with respect to image quality parameters and patient dose are described for both fihn and a digital system (Digora) using an imaging plate. In the digital system, the characteristics of the receptor affect image acquisition similarly to film but digitalized image formation and display may limit image quality (contrast resolution).
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| 18. |
- Hermansson, Ann-Charlotte, 1945-
(författare)
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War-wounded refugees : A prospective study of well-being and social integration
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is a prospective study of a culturally heterogenous group of war-wounded refugees, who arrived in Sweden in the late 1980s. The general aim was to describe the situation of warwounded refugees from medical, psychological and social perspectives after arrival and aftertwo years in Sweden and, if possible, to identify factors of significance for their well-being and social integration. The study group comprised 61 war-wounded patients admitted to somatic care. The patients were investigated during hospitalization, shortly after arrival in Sweden, andfollowed up after two years. The data collection covered medical, psychological and social conditions and was performed by personnel on the ward using interviews and rating scales. All data collection was performed with the help of interpreters. From clinical experience and a pilot study, it was expected that war-wounded refugees would be specially vulnerable. In addition, the literature on refugee migration and war trauma suggested that war-wounded refugees could be a high risk group for decreased well-being and adjustment difficulties in countries of resettlement. The type of injuries and medical complications observed in the study group were representative of small unit operations of war with poor access to early medical care. Characteristics of the refugees' background were:obstructed or interrupted schooling and working life; long periods of duty as guerillas, or other political activities; a high frequency of death and separation of family members; a high frequency of imprisonment and torture; unfavourable conditions prior to the flight. Thus, the group was heavily burdened with respect to risk factors for decreased well-being after resettlement. However, the quantitative data analysis showed that these factors had not had the influence expected on well-being following arrival or after two years in the host country.Instead, the analysis indicated that life circumstances and events related to the present situation, "here and now", were more important for their well-being and social integration. With respect to labour market attachment, the war-wounded group was found to follow wellthe expected labour market integration process for refugees. On group level, well-being had not improved after two years compared with well-being following arrival. The qualitative findings suggest that in this early stage of migration, the refugees are mourning their losses but are not observably occupied by working through the pre-migration war traumas.
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| 19. |
- Hernefalk, Leif
(författare)
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Internal fixation of femoral neck fractures
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The incidence of femoral neck fractures in elderly people is rising requiring large health care resources. Internal fixation of the fracture is the treatment of choice in Scandinavia, but in 20-40% of the cases a late complication such as a segmental collapse of the femoral head after initial bone necrosis, or a non-union of the fracture because of non-healing, will occur. Because of the high disability associated with these local complications, revision surgery is needed, and in such a case the cost more than triples. Reduction of these local complications would avoid suffering and costs. The present study focuses on the analysis of technical principles for device design and internal fixation of femoral neck fractures, with the aim to reduce the number of local complications due to non-healing. The analysis is based on animal experiments, evaluation of patients who were treated with different internal fixation techniques, and finally biomechanical in-vitro tests of osteotomized femur specimens, which were stabilized wilh different internal fixation devices.The results indicate that late complications are associated with early pronounced femoral shortening; monitoring of femoral length had, therefore, a high accuracy (92%) in predicting the late outcome. A shortening of more than 5 mm at one month predicted a greater lhan 6-fold increase of the incidence oflate complications. Use of a device that enabled a rigid osteosynlhesis reduced the incidence of non-unions, thereby reducing the overall local complication rate by one-third, and the need for revision surgery was halved. The rate of late segmental collapse, which occurred in 14-19%, remained independent of choice of device.The healing of the fracture due to a stable fixation may accelerate the course to a segmental collapse in cases with initial osteonecrosis of lhe femoral head, due to vascular impairment at injury. Otherwise a stable fracture fixation, preventing a high postoperative deformation at the fracture site, was found to be a prerequisite for optimal fracture healing. Such a stable fixation can be optimally achieved with a device incorporating two or more threaded pins or screws, preferably cannulated, which are implanted With an a traumatic technique with high precision using guide systems to prevent unnecessary damage to bone. The optimal device for internal fixation of a femoral neck fracture should also have a good grip in osteoporotic cancellous ancl subchondral bone; the good grip of suitable threads may be enhanced by bone cement.
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| 20. |
- Hjertberg, Hans, 1946-
(författare)
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The use of ethanol as a marker to detect and quantify the absorption of irrigation fluid during transurethral resection of the prostate
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During transurethral resection of the prostate (TURP), the irrigation fluid is often absorbed by the circulatory system and/or the region around the prostate occasionally resulting in severe signs and symptoms. Instant detection and quantification of absorption of irrigation fluid have not been possible earlier. A method involving tagging of the irrigation fluid with ethamol for detection and quantification of absorbed irrigation fluid by measurement of ethanol in expired breath (EB) has been developed. The validity of measuring El3 ethanol to detect and quantify absorbed irrigation fluid was studied in 13 patients undergoing TURF. The EB ethanol was compared with three other methods: 1. Isotope tagging of the irrigation fluid and detection of absorbed fluid using a scintillation detector placed over large blood vessels. 2. Measuring changes in serum-sodium every 10 min. 3. Regular interval monitoring (RIM) of the difference between volume used for inigation and volume recovered from patients every 10 min. The method of measming El3 ethanol was found to be highly valid. The possibility of detecting absorption and the incidence of absorption using EB ethanol in the clinical routine was studied in 192 patients undergoing TURP. Half of them absorbed irrigation fluid, 25% absorbed more than 400 ml. The proportion of patients absorbing inigationlhlld was the same for both experienced and inexperienced resectionists. Clinical assessment of absorption of irrigation fluid was perfonned by the resectionists and the supervising nurses in 118 patients undergoing TURP. Prerequisites for massive absorption were found by the resectionist in 8/9 patients. The resectionist falsely indicated absorption in 22 patients. The nurses conectly indicated 3/9 patients and falsely indicated 4 patients. To investigate the method measuring EB ethanol to detect absorption of inigation fluid during general anaesthesia, 20 patients undervent TURP and EB ethanol was compared to the RIM method. There was a good correlation between the methods. Elevated pressure in the bladder-prostatic fossa is a prerequisite for absorption of irrigation fluid. Detection and quantification of absorbed irrigation fluid by EB ethanol was used for eompming 102 patients operated on with and without a pressure warning device alarming at 1.5 kPa in the bladder. Using the device reduced both the volume of absorbed irrigation fluid, and the number of patients absorbing irrigation fluid. Both ethanol per se and haemodilution by absorbed irrigation fluid may have impacts on the coagulation system. To investigate the influence of absorption of ethanol tagged mannitol on bleeding time, measurements were perl'omed before and after TURP in 57 patients. No difference in bleeding time was found among patients who absorbed irrigation fluid as compared to those who did not. In conclusion, measurement of ethanol in EB for detection and qum1tification of absorbed irrigation fluid is a highly valid method when compared to three other methods. Absorption of irrigation fluid was found in 50% of the patients tmdergoing TURP. Clinical assessments of absorption of irrigation fluid are inreliable. EB ethanol can be used in patients dllling general anaesthesia. Using a pressure warning device decreases the volume of absorbed irrigation fluid, a~ well as the number of patients absorbing it. Absorption of etillmol tagged mannitol as irrigation fluid has no influence on bleeding time.
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