The renal histopathology of essential malignant hypertension in black South Africans.

The renal histopathology of essential malignant phase hypertension in two groups of black South Africans was studied. The first, an autopsy series, consisted of material obtained in 1956-1961, a period when adequate antihypertensive therapy had not yet become generally available. The second group, a renal biopsy series, was from an era when effective antihypertensive therapy was available (1979-1989). The study showed that the clinical and histopathological changes of malignant hypertension were similar in both the pre-treatment and treatment eras. Fibrinoid necrosis was found in 92% of the autopsy sections and 44% of the biopsies. While mucinous, onion-skin and fibrotic changes of the blood vessels were commonly found, they were not invariably present and could not be considered the histopathological hallmark of malignant nephrosclerosis. It was often impossible on histological examination to distinguish malignant nephrosclerosis arising de novo from that superimposed on long-standing previous benign hypertension. Replication of internal elastic lamina, which has been considered a marker of long-standing previous benign hypertension, was a nonspecific finding and was frequently observed in young hypertensive subjects with a short clinical history. When fibrinoid necrosis is present, diagnosis of malignant nephrosclerosis can be made with confidence in black South Africans.

Angiology of the brain of the baboon Papio ursinus, the vervet monkey Cercopithecus pygerithrus, and the bushbaby Galago senegalensis.

The investigation was undertaken to compare the blood supply and venous drainage of the brain of the baboon P. ursinus, the vervet monkey C. pygerithrus, and the bushbaby G. senegalensis with that of man, because these animals are extensively used as research models. The blood supply of the three primates was found to be similar in each case. Like man they have a complete circulus arteriosus; but they have a single anterior cerebral artery, whereas man has paired anterior cerebral arteries. The arterial supply to the cerebellum in the primates is similar to that in man, the main difference being a "common inferior cerebellar artery" which bifurcates to form the anterior inferior cerebellar and posterior inferior cerebellar arteries. In man, these arteries arise separately from the basilar artery and vertebral arteries, respectively. The dural venous drainage was also found to be similar in these primates but was far more extensive than in man. The primates have additional sinuses--the more important of these being the "basisphenoid sinus" and the petrosquamous sinus. The former drains the basilar sinus and is itself drained via the vertebral venous plexus and internal jugular vein. The latter drains via the petrosquamous foramen into the retromandibular vein. The petrosquamous sinus has a rostral extension which drains through the foramen ovale and two lateral and medial connecting sinuses which drain the cavernous and basilar sinuses, respectively. These sinuses are not found in man.

Hypertension in black South Africans--new perspectives on old material.

Autopsy material was examined from cases diagnosed as malignant nephrosclerosis in the years 1956-1961, a period when adequate antihypertensive therapy had not yet become available, a second group of malignant nephrosclerosis from the years 1970-1980, an era during which effective antihypertensive therapy was available, and a third group of essential benign nephrosclerosis, once more from the early pretreatment period (1956-1961). The observations suggest that malignant and benign hypertension may be two different diseases. Further studies will be pursued to assess whether hypertensive renal changes seen in this study are a spectrum of one disease extending from malignant nephrosclerosis de novo presenting with acute renal failure or chronic renal failure to benign hypertensive nephrosclerosis.

Wegener's granulomatosis in an 11-year-old child. A case report.

Early diagnosis and treatment of Wegener's granulomatosis with cyclophosphamide has considerably improved the prognosis in this previously fatal disease. Experience with this disease in an 11-year-old child is reported.

Normothermic ischaemic cardiac arrest of the isolated perfused rat heart: effects of trifluoperazine and lysolecithin on mechanical and metabolic recovery.

To evaluate the hypothesis that maintenance of the integrity of myocardial membrane systems and prevention of Ca2+ influx into the cell are significant in the survival of ischaemic tissue, the effect of trifluoperazine and lysolecithin, were tested on the recovery of globally ischaemic rat hearts. Trifluoperazine increases membrane stabilization, inhibits calmodulin and binds to other Ca2+-dependent proteins. Lysolecithin, on the other hand, has a detergent action on myocardial cell membranes and facilitates Ca2+ ingress in ischaemic tissue. With trifluoperazine (2.45 microM), added before induction of ischaemia or during reperfusion only, hearts subjected to 40 min normothermic ischaemic cardiac arrest recovered mechanically. Untreated hearts failed after 20 min of ischaemia. The drug had no effect on tissue high energy phosphate levels or mitochondrial oxidative phosphorylation. Conversely, lysolecithin (2.5-10 microM) caused all hearts to fail after being subjected to 15 min ischaemia. Mechanical failure during reperfusion of such hearts was associated with a significant reduction in tissue ATP and CrP levels. Trifluoperazine counteracted the harmful effects of lysolecithin to a limited extent.

Normothermic ischaemic cardiac arrest and reperfusion of the isolated working heart: effect of chlorpromazine on functional, metabolic and morphological recovery.

The effects of chlorpromazine, an inhibitor of both Ca2+ flux and phospholipase activity, on myocardial ultrastructure, function and metabolism were assessed during normothermic ischaemic cardiac arrest and reperfusion of the isolated working rat heart. Normothermic ischaemic cardiac arrest produced significant changes in myocardial ultrastructure, high energy phosphate contents and mitochondrial oxidative phosphorylation within 20 min. Reperfusion of untreated hearts subjected to 20 and 25 min ischaemia failed to restore mitochondrial function, mechanical activity and ATP content to control, pre-ischaemic levels. Morphological signs of ischaemic injury regressed, especially in the subendocardial layer. Pretreatment of hearts with chlorpromazine did not prevent the ischaemia-induced changes in myocardial ultrastructure and mitochondrial function. However, during reperfusion the chlorpromazine-treated, totally ischaemic heats (20 to 25 min) exhibited improved coronary flow rates, and ultrastructural and mechanical recovery. The mitochondrial oxidative phosphorylation process and tissue high energy phosphate contents were not affected by the drug.

Experimental microsurgery in peripheral nerves.

A surgical technique for the reconstruction of severed peripheral nerves is described. This technique reduces the mechanical manipulation and trauma to the nerve during suturing. Histological studies revealed that scar formation at the suture site was reduced to a minimum. The suture material did not prevent the downgrowth of regenerating axons. Nerves in which suturing was either inaccurately or accurately done, were compared. Histological examination of these nerves revealed that axonal regeneration in nerves with 8 or more sutures was superior to that in nerves with only 2 sutures.