On the site of decreased fluid reabsorption after release of ureteral obstruction in the rat

Fluid reabsorption in surface nephrons was studied by micropuncture 3 hours after release of complete left ureteral ligation (LUL) or after unilateral release of bilateral ureteral ligation (BUL). In 11 rats with LUL, glomerular filtration rate (GFR) averaged 0.23 +/- 0.04 ml. per minute in the experimental vs. 1.25 +/- 0.11 ml. per minute in the control kidney. GFR averaged 0.18 +/- 0.02 ml. per minute in BUL. Single nephron glomerular filtration rate (SNGFR) was decreased in the experimental kidney of LUL or BUL when determined at proximal or distal sites as compared to the SNGFR determined in shams or the left kidney following right ureteral ligation (RUL). Fractional water excretion was increased after release of obstruction. LUL 2.72 +/- 0.66 per cent; BUL 12.3 +/- 2.82 per cent when compared to sham-operated rats (0.48 +/- 0.07 per cent) or to the untouched kidneys of the RUL group (0.60 +/- 0.09 per cent). Despite increased water and sodium excretion after release of unilateral ureteral ligation and BUL there were marked differences in tubular fluid reabsorption between these two groups. Following release of LUL there was increased fractional water reabsorption along the accessible length of surface nephrons of the experimental kidney. At 55 per cent of proximal tubular length TF/Pin averaged 4.02 +/- 0.02 in LUL vs. 2.18 +/- 0.06 in shams. The mean TF/Pin at 90 per cent of distal tubular length was 31.0 +/- 1.37 in LUL vs. 10.6 +/- 0.08 in sham-operated rats. In contrast, water reabsorption after BUL was slightly but significantly suppressed proximally (TF/Pin 1.95 +/- 0.02) and markedly depressed distally (TF/Pin 3.35 +/- 0.29). These results suggest that the change in fluid reabsorption observed after relief of LUL is located at a site beyond the accessible length of surface nephrons, most likely in the collecting duct. However, the data could also be explained by alterations in fluid reabsorption in deep nephrons. The changes in fluid reabsorption seen following release of BUL reflect the additive effects of release of obstruction and a marked reduction in functioning nephron mass.

The adherence of human Fc receptor-bearing lymphocytes to antigen-antibody complexes. II. Morphologic alterations induced by the substrate

The adhesion of human Fc receptor-bearing lymphocytes to immobilized antigen-antibody complexes is accompanied by marked alterations in cell shape, resulting in flattening of greater than 90% of the adherent cells. In addition, about 65% of the adherent cells become elongated, with distinct uropods being present in about 1/3 of these cells. Scanning electron microscopy demonstrates that most of the surface microvilli are lost, while ruffled membranes and long microextensions are formed during the shape change. Time-lapse cinematography shows that the major shape changes occur within a few minutes after contact with the substrate, and that the adherent cells undergo translational motility. Both flattening and elongation of the adherent cells are inhibited by low temperature, chelating agents, cytochalasin B, and vinblastine, while sodium azide selectively inhibits elongation and uropod formation. It is argued that these morphological changes result from an active response of the cell to the immobilized complexes, and that such alterations may be related mechanistically to the ability of the cells to kill antibody-coated target cells.

Successful treatment of non-meningitic listerial brain abscess without operation

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Recurrent and multiple suture closures after craniectomy for craniosynostosis

✓ Six cases of craniosynostosis are reported in which recurrent and multiple closure of cranial sutures occurred after craniectomy and insertion of polyethylene film. In all patients there was closure of a second and sometimes a third suture as well as reclosure of the treated suture. In four children the second operations were done before the age of 18 months; none had increased intracranial pressure preoperatively and three who are living have normal intelligence. In two children, the second operations were not done until after the age of 3 years; both had increased intracranial pressure preoperatively, and both are now mentally retarded.

Kenneth George McKenzie, Canada's first neurosurgeon

✓ In his presidential address to the Society of Neurological Surgeons, the author commemorates a previous president of the society, Dr. Kenneth G. McKenzie, by relating reminiscences of his own and anecdotes told by colleagues and former residents of Dr. McKenzie.

Crouzon's disease (craniofacial dysostosis). Modern diagnosis and treatment

✓ This article discusses the nature and treatment of Crouzon's disease and reproduces a translation of part of Crouzon's original description. Six typical patients with this disease are presented, and the reasons for surgical treatment emphasized.

Acrylic fixation of atlanto-axial dislocations. Technical note

✓ An operative technique using methyl methacrylate (acrylic) and wiring for the treatment of atlanto-axial dislocations is described. Long-term evaluation of a series of patients indicates that this is a safe and effective method of obtaining cervical fixation.

Kyphoscoliosis following lumbar subarachnoid shunts

✓ In a follow-up of 80 lumbar subarachnoid shunts for hydrocephalus, scoliosis with limitation of back flexion was found to have developed in approximately 50% of the surviving children, some of whom showed a disparity in the length and size of their legs. There was no correlation between the direction of the convexity of the scoliosis and the side of the shortened leg, or between the number of shunt revisions and the ultimate development of kyphoscoliosis, or between removal of laminae and the subsequent development of scoliosis. Three case histories are presented to illustrate the still unproven but possible relationship between arachnoiditis due to polyethylene tubes and the ensuing scoliosis. Removal of the lumbar shunts, decompression, and laminectomy seemed to have no beneficial effect in the reversal of the scoliosis in any of the cases reviewed.

Surgical treatment of brain stem gliomas

✓ A long-term study has been made of a consecutive series of 37 patients with brain stem gliomas, 22 of whom were children and 15 adults. Surgical exploration was carried out in 34 of the 37 cases and only very rarely was a diagnosis made on clinical grounds or air study alone. In 10 cases a histological diagnosis was made at operation. In five patients a significantly large neoplastic cyst was found and evacuated, and four of these have had long-term useful survivals. There were nine postoperative deaths, most of them in the pre-Decadron era; 17 cases died during follow-up, with a mean survival of 33 months; and eight patients are living, with a mean survival of 3 months to 9 years. A plea is made for surgical exploration of these lesions in the hope of finding a surgically approachable cyst, and for the use of radiation therapy at a later time.

Unilateral amaurosis in a hydrocephalic child with an obstructed shunt

✓ A 7-year-old child with treated hydrocephalus became blind in the left eye as a consequence of malfunction of the ventriculoatrial shunt. This complication probably could have been avoided by elective revision of the shunt with growth.

Effects of local hypothermia and tissue oxygen studies in experimental paraplegia

✓ A controlled series of adult mongrel dogs were rendered paraplegic by traumatizing the thoracic spinal cord. Those animals treated with local hypothermia, whether immediately or after a delay, recovered to a significantly greater degree than the untreated group. Spinal cord pO2 studies revealed a marked fall in the pO2 at the area of maximal injury over a 30-min period. The severe hypoxia lasted at least 7 hours. Pathological studies showed the varying degrees of injury produced. It is postulated that local hypothermia may be effective in altering the clinical recovery by decreasing the tissue metabolism at the site of injury.