| 1. |
- Grøgaard, B, et al.
(författare)
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The polymorphonuclear leukocyte : has it a role in fracture healing?
- 1990
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Ingår i: Archives of Orthopaedic and Trauma Surgery. - 0936-8051 .- 1434-3916. ; 109:5, s. 268-71
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to assess whether the presence of polymorphonuclear leukocytes in the first stage of fracture repair was of any importance. In anesthetized male Wistar rats, a transverse osteotomy was performed at midshaft in one femur and immediately stabilized by an intramedullary Kirschner nail. The animals were allowed unprotected weight bearing immediately. Nine animals were made neutropenic before operation by injection of a specific rat polymorphonuclear leukocyte antiserum (antineutrophil serum, ANS) raised in sheep. The number of circulating polymorphonuclear leukocytes were kept below 20% of their normal value for 72 h postoperatively by intraperitoneal injections of ANS every 12 h. Control animals were injected with the same amount of normal sheep serum (NSS). All animals received cefuroxime (100 mg/kg day) concomitantly with the ANS injections. Six weeks after operation the animals were killed, the amount of callus formation was measured, and the bones were radiologically examined. The nails were then removed and both the healing fractures and the nonoperated femurs mechanically tested for bending. There were no differences in the amount of callus measured or in radiological healing. However, there was a significantly higher bending moment in femurs from animals treated with ANS than in those given NSS (P less than 0.02). No differences were observed in rigidity or total energy absorption.
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| 2. |
- Holtz, A, et al.
(författare)
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Effect of methylprednisolone on motor function and spinal cord blood flow after spinal cord compression in rats.
- 1990
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Ingår i: Acta Neurologica Scandinavica. - 0001-6314 .- 1600-0404. ; 82:1, s. 68-73
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Tidskriftsartikel (refereegranskat)abstract
- The effect of methylprednisolone (MP) on neurologic recovery and spinal cord blood flow (SCBF) was investigated up to 4 days after a spinal cord compression injury in rats. The injury was produced at midthoracic level by applying a load of 35 g on a 2.2 x 5.0 mm compression plate for 5 min, which resulted in transient paraparesis. MP was given as a bolus dose of 30 mg/kg i.v. 60 min after injury (n = 20) and controls were given saline (n = 10). The motor performance was assessed daily as the capacity angle on the inclined plane and SCBF was measured by 14C-iodoantipyrine autoradiography on Days 1 or 4. On Day 1 the capacity angle was reduced from about 63 degrees preoperatively to 33 +/- 2 degrees (mean +/- SEM) in the control group and to 50 +/- 1 degrees in the group treated with MP (p less than 0.05). Thereafter there was a slight improvement in both groups, but the difference persisted throughout the observation period. On Day 4 both gray and white matter SCBF was better preserved in MP-treated animals than in the control group (59 +/- 4 versus 49 +/- 3 ml/min/100 g tissue for gray matter and 13.6 +/- 0.6 versus 10.7 +/- 0.8 ml/min/100 g tissue for white matter). Posttraumatic treatment with MP, thus, improved both the neurologic recovery during the first 4 days and SCBF as measured on Day 4. It is speculated that the effect of MP is at least partly exerted on the vascular bed.
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| 3. |
- Holtz, A, et al.
(författare)
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Neuropathological changes and neurological function after spinal cord compression in the rat.
- 1990
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Ingår i: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 7:3, s. 155-67
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Tidskriftsartikel (refereegranskat)abstract
- As part of a series of experimental investigations of the effects of various pharmacological agents on the outcome of compressive spinal cord trauma in the rat, the time course of the cell changes in the cord at the site of and distal to the compression was studied at the light microscopic level. The degree of compression used with the present model results in a transient paraparesis that recovers almost completely over a period of 3 weeks as judged by the inclined plane technique. The most significant morphological findings were as follows. Initially (1 and 24 h after the impact) there was pronounced swelling and hemorrhage at the compression site, chiefly in the gray matter of the cord. On day 4 there was severe necrosis in the same region, with numerous macrophages and leukocytes. Rats killed after 21 days showed either minor residual signs of necrosis or essentially normal tissue architecture. Surprisingly, necrosis with delayed onset also developed in the dorsal columns, involving the pyramidal tracts. This necrosis was detected in animals killed after 9 and 21 days but not in those observed after 4 days or earlier. The longitudinal tracts of the white matter showed reduced staining in paraffin sections of the compression site. Epon sections revealed splits in the myelin sheaths and enlarged periaxonal spaces as early as 1 h after the impact. The alterations in the longitudinal tracts persisted throughout the 21-day observation period and extended down to L2-L4. There was gradual functional recovery, documented by the inclined plane test. Preinjury values were almost reached on day 21, although the cord still showed some morphological damage. In individual animals, no relation was found between degree of function as tested by inclined plane and extent of morphologic injury. Additional functional and morphological methods obviously are needed in future investigations of the effects of treatments on the outcome of compressive spinal cord injury.
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| 4. |
- Holtz, A, et al.
(författare)
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Relation between spinal cord blood flow and functional recovery after blocking weight-induced spinal cord injury in rats.
- 1990
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Ingår i: Neurosurgery. - 0148-396X .- 1524-4040. ; 26:6, s. 952-7
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Tidskriftsartikel (refereegranskat)abstract
- Spinal cord blood flow (SCBF) and motor performance on the inclined plane were measured up to 9 days after a reversible spinal cord compression injury in 49 Sprague-Dawley rats. A load of 35 g on 11 mm2 of the thoracic spinal cord for 5 minutes caused transient paraparesis with a decrease in the capacity angle on the inclined plane from 62 +/- 1 degree (mean +/- SEM) before injury to 33 +/- 1 degree on Day 1, 45 +/- 2 degrees on Day 4, d and 54 +/- 3 degrees on Day 9. SCBF was measured by the [14C]iodoantipyrine method, and in gray matter there was a decrease from 78.4 +/- 2.3 ml/min/100 g of tissue in uninjured animals to 33.7 +/- 1.5 ml/min/100 g of tissue on Day 1 after injury, increasing to 50.1 +/- 2.0 on Day 4 and to 70.5 +/- 2.7 ml/min/100 g of tissue on Day 9. At the corresponding times, the SCBF values in white matter were 14.5 +/- 0.5, 6.7 +/- 0.5, 10.2 +/- 0.6, and 13.4 +/- 0.6 ml/min/100 g of tissue, respectively. The animals in another group were loaded with 25 g for 5 minutes and on Day 1 exhibited a capacity angle of 43 +/- 2 degrees while the SCBF values for gray and white matter were 55.1 +/- 2.0 and 11.1 +/- 0.4 ml/min/100 g of tissue, respectively; thus, the results in this group were similar to the values on Day 4 in the animals loaded with 35 g.(ABSTRACT TRUNCATED AT 250 WORDS)
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| 5. |
- Hällgren, R, et al.
(författare)
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Accumulation of hyaluronan (hyaluronic acid) in myocardial interstitial tissue parallels development of transplantation edema in heart allografts in rats.
- 1990
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Ingår i: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 85:3, s. 668-73
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Tidskriftsartikel (refereegranskat)abstract
- By using biotin-labeled proteoglycan core protein, hyaluronan (hyaluronic acid; HA) was visualized in rat heart grafts at different times (2, 4, and 6 d) after transplantation. In normal, nontransplanted hearts HA was present in the adventitia of arteries and veins and in the myocardial interstitial tissue. An increased accumulation of HA was evident in the edematous interstitial tissue, infiltrated with lymphocytes, on day 4 after allogeneic transplantation, and was even more pronounced by day 6. No apparent increase in HA was seen in syngeneic grafts. Biochemical assay of HA in heart tissue demonstrated that the myocardial content of HA had increased 60% by day 2 after transplantation in allogeneic as well as syngeneic grafts, indicating that surgical trauma may induce some HA accumulation in heart grafts. The extractable amount of HA declined during the following days in the syngeneic grafts, but increased progressively during the development of rejection in the allogeneic grafts, and increased on average three times by day 6. The relative water content also increased progressively during rejection of allogeneic grafts and correlated with the HA accumulation. The interstitial accumulation of HA, a glycosaminoglycan with unique water-binding qualities, is presumably implicated in the development of interstitial edema during rejection of heart grafts.
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| 6. |
- Hällgren, R, et al.
(författare)
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Hyaluronic acid accumulation and redistribution in rejecting rat kidney graft. Relationship to the transplantation edema.
- 1990
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Ingår i: Journal of Experimental Medicine. - 0022-1007 .- 1540-9538. ; 171:6, s. 2063-76
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Tidskriftsartikel (refereegranskat)abstract
- By using biotin-labeled proteoglycan core protein and an avidin-enzyme system, hyaluronic acid (HA) was visualized in rat kidney. In the normal kidney, HA was localized in the extracellular space of the inner medulla and increased markedly towards the papillary tip. No staining for HA was seen in the interstitial tissue of the cortex or the outer medulla. During the development of rejection of allogeneic renal grafts, a progressive increase in accumulated HA was seen in the interstitial tissue of the cortex and outer medulla. The extractable amounts of HA increased, on average, 40 times in the cortex and outer medulla; no increase was measured in the inner medulla and papilla. The relative water content of the cortex and outer medulla also increased progressively and correlated with the HA accumulation. The extractable amounts of HA in syngeneic grafts increased by day 2 and then leveled off, indicating that surgical trauma may induce some transient HA accumulation after transplantation. Interstitial accumulation of HA, a glycosaminoglycan with unique water-binding qualities, would presumably influence water transport and osmotic activity and should thereby be implicated in the normal papillary function, but also in the development of the interstitial edema of the cortex and outer medulla during rejection of renal grafts.
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| 7. |
- Schürer, L, et al.
(författare)
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Effects of neutrophil depletion and superoxide dismutase on postischemic hypoperfusion of rat brain.
- 1990
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Ingår i: Advances in Neurology. - 0091-3952. ; 52, s. 57-62
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Tidskriftsartikel (refereegranskat)abstract
- In the present investigation, the involvement of PMNLs and oxygen free radicals was explored in rats with postischemic perfusion disturbances of the brain. Reversible forebrain ischemia was induced by bilateral clamping of both carotid arteries in combination with hemorrhagic hypotension. This procedure resulted in a reproducible DPH 1 hr after start of recirculation. Neutropenia was induced by sheep ANS. One group received ANS before and a second group immediately after termination of ischemia. Two additional groups received SOD before or immediately after ischemia. Regional postischemic CBF was determined by [14C]iodoantipyrine autoradiography. It was found that CBF significantly improved in cortical structures of animals treated with ANS before ischemia. Treatment with ANS at the end of ischemia had no effect on the postischemic CBF depression. Neither was injection of SOD effective to influence DPH, irrespective whether given before or after ischemia. It is concluded that PMNLs play a role in the development of DPH of the brain, whereas free radical mechanisms seem to be less relevant.
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| 8. |
- Schürer, L, et al.
(författare)
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Is postischemic hypoperfusion related to brain edema?
- 1990
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Ingår i: Advances in Neurology. - 0091-3952. ; 52, s. 155-64
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Tidskriftsartikel (refereegranskat)abstract
- The effect of reversible cerebral ischemia on brain edema development was studied with a gravimetric method. CBF changes after ischemia were correlated with alterations in brain SG. Forebrain ischemia (15 min) was induced in rats by reversible bilateral ligation of both carotid arteries plus induction of controlled hypotension to 50 mm Hg. The SG of different brain structures was determined in a Percoll column up to 24 hr after ischemia. In addition, rCBF was measured by [14C]iodoantipyrine autoradiography. Cerebral ischemia resulted in reduction of CBF to less than 1% of normal in cortical structures and the caudatoputamen. One hour after the end of ischemia, blood flows were still reduced to 30% to 50% of the control level indicative of DPH. SG in cortex and hypothalamus reached a maximal decrease 10 min after the end of the ischemia and was still significantly reduced at 1 hr, although it was normal again 6 hr later. Regression analysis revealed a significant correlation between CBF obtained during ischemia and the corresponding SG found at 10-min recirculation, which could also be established at 1-hr recirculation. Therefore, a causal relation between the development of the DPH and the formation of ischemia might be considered.
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| 9. |
- Schürer, L, et al.
(författare)
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Superoxide dismutase does not prevent delayed hypoperfusion after incomplete cerebral ischaemia in the rat.
- 1990
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Ingår i: Acta Neurochirurgica. - 0001-6268 .- 0942-0940. ; 103:3-4, s. 163-70
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Tidskriftsartikel (refereegranskat)abstract
- Local cerebral blood flow (1CBF) was measured autoradiographically 60 minutes after 15 minutes of forebrain ischaemia in rats treated with superoxide dismutase (SOD) before (50 mg.kg-1 body weight) or at the end of the ischaemia period (4 mg.kg-1 body weight). Incomplete forebrain ischaemia was produced by a combination of common carotid artery occlusion and bleeding to a mean arterial blood pressure of 50 mmHg. During ischaemia the 1CBF values in cortical areas were less than 3% of the preischaemic values and treatment with SOD prior to ischaemia did not influence 1CBF during ischaemia. Sixty minutes after termination of cerebral ischaemia the 1CBF values were decreased to between 40 and 60% of values found in control animals. Neither form of treatment improved the postischaemic cerebral blood flows. The results imply that postischaemic flow disturbances in the brain may not be due to extracellular superoxide production.
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| 10. |
- Wadström, J, et al.
(författare)
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An in vivo method for studies of traumatic vasospasm.
- 1990
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Ingår i: Microsurgery. - 0738-1085 .- 1098-2752. ; 11:3, s. 197-203
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Tidskriftsartikel (refereegranskat)abstract
- A study was undertaken to develop a model for investigations of traumatically induced vasospasm. The left ear of the rabbit was denervated under short anesthesia. With the animal under light sedation, spasm of the central ear artery was repeatedly induced with a clip applying forceps. To evaluate the vasospasm, the vessel was transilluminated with cold light, and the internal diameter was continuously measured. The spasm was assessed in terms of its duration, intensity (reduction of initial diameter) and severity (integrated change in diameter over time). Repetitive application of the forceps on the same vessel segment shortened the spasm duration. With prolonged pinch duration, the spasm duration was lengthened. The preparation was stable for at least 3 hours. This model was effective for manipulating small vessels and producing spasm and is of potential value for studying the treatment of vasospasm by topical local intra-arterial and systemic methods.
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