Toxemia of pregnancy in sheep: a clinical, physiological, and pathological study.

Toxemia was induced in 13 of 20 pregnant ewes by the stress of a change in environment and food deprivation late in pregnancy. Of the toxemic ewes, eight developed prominent neurological findings with convulsions, motor weakness, and blindness, whereas five ewes developed azotemia without neurological signs. Proteinuria and azotemia occurred in all but one of the toxemic animals. Seven animals did not develop clinical or laboratory evidence of toxemia. Hypertension did not occur with the onset of toxemia but all toxemic animals showed glomerular changes by light and electron microscopy. These abnormalities, which were similar to those seen in human preeclampsia, included endothelial cell swelling, focal reduplication of the basement membrane, and fusion of the epithelial cell foot processes. The toxemia could not be attributed to changes in hematocrit, plasma glucose, Na, Cl, CO(2), K, Ca, fibrinogen, arterial pH, lactate, or pyruvate concentrations. Cardiac output fell only in ewes with prominent neurological signs. Plasma renin rose strikingly in animals developing toxemia, without change in substrate concentration. In contrast to human and other species, sheep uterus and amniotic fluid contained no detectable quantities of renin. Thus in response to stress the pregnant ewe develops a toxemia which in the absence of hypertension has clinical and pathological similarities to human preeclampsia.

Histiocytoid cardiomyopathy of infancy: an unexplained myofibre degeneration.

An unusual multifocal degeneration of the myofibres of all chambers and the conducting system of the heart was found in a 4-month-old female in whom ventricular pre-excitation (Wolff-Parkinson-White syndrome) had been demonstrated. There was a complex malformation of the brain with hydrocephalus and bilateral corneal opacities and microphthalmos. The affected myofibres had a swollen vacuolated or granular cytoplasm and rounded nuclei giving a histiocytoid appearance. Disruption of myofibrils and gross dilation and disorganization of mitochondria were the major fine structural features. Reports of similar lesions in 8 other young female children are reviewed. 'Histiocytoid cardiomyopathy' is the term preferred over others which refer to an increased lipid content. The aetiology is unknown.

Experimental autoimmune glomerulonephritis in the rat. I. Factors influencing induction.

Albino Holtzman, albino Wistar and hooded HS rats were injected fortnightly for 14 weeks with human glomerular basement membrane (GBM) emulsified in Freund's complete adjuvant. Half of the rats were pretreated with Freund's complete adjuvant and some were unilaterally nephrectomized. Anti-GBM antibody glomerulonephritis, characterized by proteinuria (greater than 100 mg/16 h) and a diffuse linear deposition of host immunoglobulin along the glomerular basement membrane, was first detected in Holtzman rats 4 weeks after treatment with GBM had begun, and had developed in 69% of these rats by 15 weeks. In contrast, none of the similarly treated Wistar or HS rats became proteinuric at any time, although a few showed weak glomerular fluorescence at the end of the experiment. Thus Holtzman rats are susceptible, and HS and Wistar rats are resistant to experimental anti-GBM antibody glomerulonephritis. Pretreatment with Freund's complete adjuvant apparently shortened the induction period of the experimental disease in the Holtzman rats whereas unilateral nephrectomy appeared to decrease their susceptibility to it.

Experimental autoimmune glomerulonephritis in the rat. II. A histopathological and fine structural study.

Human glomerular basement membrane (GBM) emulsified in Freund's complete adjuvant was injected into 16 Holtzman rats. Eleven (69%) of them subsequently developed glomerulonephritis. This disease was characterized by glomerular changes which included focal lobular hypercellularity due to localized hyperplasia of intracapillary (mesangial or endothelial) cells which often obstructed glomerular capillaries. Later, affected lobules showed necrosis of intracapillary cells, and capillary lumina were filled with homogeneous eosinophilic material. An immunoperoxidase technique revealed autologous anti-GBM antibody in all 3 layers of the GBM and in some regions it was present in greater amount in the lamina rara interna and externa than in the lamina densa. Experimental auto-immune glomerulonephritis in the rat is thus characterized morphologically by a focal proliferative glomerulonephritis which proceeds to focal glumerulosclerosis.

The pathogenesis of renal allograft rejection: an experimental investigation in sheep.

Fifteen renal allografts and 5 autografts were placed into the necks of bilaterally nephrectomized sheep. Ten of the sheep with allografts were also treated with azathioprine (5 mg/kg) and prednisone(1.5 mg/kg) daily. There were no changes in the distribution of immunoglobulins or of beta lC globulin which could be associated with the rapid decline in glomerular filtration rate observed in untreated allografts after 2 d and in immunosuppressed allografts after 6 d. However, this functional decline was associated with the development of interstitial oedema, lymphocyte infiltration, swelling of tubular and glomerular cells, and necrosis of the outer two-thirds of the renal cortex. Thus the onset of progressive cortical ischaemia appears to be an important event leading to renal allograft failure in sheep.

Malignant melanoma of the uveal tract--a review of the Auckland experience.

Ninety-three cases of malignant melanoma of the uveal tract diagnosed in Auckland between April 1960 and July 1984 were reviewed to determine the significant pathological factors for predicting prognosis. Six factors correlating with outcome were: extension of the tumour into and through sclera or into optic nerve, tumour size, cell type, mitotic rate, pigmentation, vascularity.

The distribution of dextran macromolecules in the glomeruli of normal and nephrotoxic rats.

The incorporation of intravenously injected dextran molecules (molecular weight 500,000 & 2,000,000) by the glomeruli of laboratory rats was studied by electron microscopy. In normal rats some dextran molecules were observed 12 minutes after injection in vesicles and invaginations of both endothelial and mesangial cells. Rats with nephrotoxic serum nephritis showed extensive separation of endothelial cells from the glomerular basement membrane. These subendothelial spaces contained irregular granular material, cytoplasmic extensions of mesangial cells and, in animals injected with dextran, dense accumulations of dextran molecules. There was no apparent difference in distribution of the two test samples of dextran. These findings demonstrated the involvement of both endothelial and mesangial cells in the glomerular localization of circulating material and indicated that immunologically inactive macromolecules can be incorporated into subendothelial deposits following immunological injury to the glomerulus.

Lipoid nephrosis and focal glomerulosclerosis.

Forty-one renal biopsies from 34 patients presenting over a 7-year period with the nephrotic syndrome or significant proteinuria and considered initially to be cases of lipoid nephrosis have been reviewed, and the results correlated with clinical findings. Lipoid nephrosis was confirmed in 25 of the patients (20 males, 5 females) 6 of whom showed a small proportion of completely sclerosed glomeruli. Twenty-two of these patients were in remission at the time of review. Nine of the patients (4 males, 5 females) showed features typical of focal glomerulosclerosis; only 4 of these were in remission, 4 showed continuing proteinuria, and one had died. The study emphasizes the importance and problems of distinguishing lipoid nephrosis from focal glomerulosclerosis.

A comparison of the effects of ischemia and of selective occlusion of capillaries, pre-capillaries and terminal arterioles on coronary reperfusion.

To study the 'no-reflow' phenomenon is ischemic myocardium, the effects of ischemia and selective embolic blockade of capillaries, precapillaries and terminal arterioles were compared in isolated rat hearts. Hearts received oxygenated Krebs-Henseleit buffer for 10 min via an aortic cannula, and then coronary perfusion was stopped. The pattern and extent of reperfusion after 15-90 min of global ischemia and after the injection of 9, 15 or 55 mu diameter microspheres were determined from the distribution of injected 6.7% fluorescein isothiocyanate-dextran in frozen transverse sections of the ventricles. Following ischemia, progressively larger subendocardial regions surrounding the left ventricle could not be reperfused. In contrast, embolic occlusion of capillaries, precapillaries or terminal arterioles caused a transmural reduction in perfusion and a fine linear or herringbone pattern of fluorescence. Sixty min of ischemia followed by microsphere injection had no effect on the subendocardial zone of no-reflow but much reduced the intensity of fluorescence elsewhere. Thus thrombosis, erythrocyte plugging and occlusion of capillaries, precapillaries or terminal arterioles are unlikely to be primary causes of the reperfusion defect which develops in ischemic myocardium.

The development of glomerular crescents in sheep.

Renal allografts were transplanted into 10 sheep with pre-existing experimental autoimmune glomerulonephritis. Serial biopsy samples were examined by light, electron and immunofluorescence microscopy. Sections were stained with naphthyl acetate to demonstrate non-specific esterase activity. Host antiglomerular basement membrane antibody was demonstrated in graft glomeruli only 30 min after transplantation, at which time up to 40% of glomeruli contained many intracapillary neutrophils. Three d after transplantation gaps in the glomerular basement membrane were evident and the urinary spaces contained polymorphonuclear leucocytes, red blood cells, large amounts of fibrin and occasional mononuclear leucocytes. These mononuclear cells had increased greatly in number by the 6th d and most contained phagocytic vacuoles. From the 7th to the 10th d the incidence of glomerular crescents increased to involve 80% of glomeruli, and the majority of cells within crescents showed phagocytic vacuoles. The number of cells exhibiting non-specific esterase activity increased markedly during the post-operative period and most were located within the urinary spaces. These results suggest that the majority of cells in the glomerular crescents were macrophages which were probably derived from blood monocytes.

Recurrence of antiglomerular basement membrane glomerulonephritis in sheep renal allografts.

Renal autografts and allografts were placed in the necks of nephrectomized sheep. Some of the sheep which received allografts had been previously injected with human glomerular basement membrane to induce an autoimmune antiglomerular basement membrane glomerulonephritis. All previously diseased and normal recipient animals were treated wtih azathioprine and prednisone from the day before transplantation. The autografts and immunosuppressed allografts in normal recipients functioned similarly for the first 6 d, but subsequently the allografts deteriorated. Allografts in untreated recipients functioned for less than 3 d. Most (90%) of the allografts in previously diseased sheep developed heavy proteinuria and haematuria immediately after transplantation and their renal function remained low. These grafts showed severe glomerular lesions by the third day, and by 8 d more than 50% of the glomeruli contained crescents. At corresponding intervals the glomeruli of autografts and allografts in normal recipients showed only minor changes. These results demonstrate that antiglomerular basement antibodies circulating in the host at the time of transplantation are a significant threat to the survival of renal allografts.

The response of three inbred strains of rat to the carcinogen 1,2-dimethylhydrazine.

Rats of 3 inbred strains (DA, HS and AS2) were dosed with 1,2-dimethylhydrazine 2HCl (DMH) or saline by gavage weekly for 10 wk. DA and HS rats showed little overt toxic reaction but all AS2 rats died following DMH doses of 30 mg/kg. However, at 10 mg/kg 60% of AS2 rats survived the 30 wk experiment. All DA rats developed a high yield of adenocarcinoma of the bowel (means: males 6.8 tumours/large bowel and 0.8/small bowel; females 2.8/large and 0.08/small bowel) and one-third of the males developed tumours of the ear canal. A smaller proportion (52%) of HS rats developed tumours, specifically bowel tumours (means: male 1.4/large and 0.2/small bowel; females 0.4/large and 0.1/small bowel). Even on the lower dose of DMH AS2 rats showed extensive liver changes including cystic cholangioma (58%), angiosarcoma (25%) and hepatocellular carcinoma (8%) and 83% developed bowel tumours (means: males 2.3/large and 1.5/small bowel; females 3.5/large and 1.0/small bowel). The rapid induction and high yield of bowel tumours, the different toxicity of DMH in AS2 rats, and the differences in relative tumour density both between sexes and in the various segments of the bowel indicate the potential of these strains for studies of carcinogenesis in the bowel.

An experimental evaluation of staining techniques for the detection of early ischaemic injury to the myocardium.

A series of experimental infarcts of the posterior papillary muscle of the canine heart was used to assess the value of 6 special stains in the histological detection of early myocardial infarction. The infarcts were of 5-720 min duration and were compared not only with normal control myocardium but also with normal myocardium autolyzed for similar periods of time. All tissue was stained with H & E, PAS, PAS-diastase, PTAH, Masson's trichrome, Connor's modification of the acid fuchsin method, Puchtler's PAS-navy blue, and Lie's haematoxylin-basic fuchsin-picric acid. The zone of severely altered myofibres which separated normal from ischaemic tissue in infarcts aged 2 or more hours was demonstrated by all but PAS. Normal, border, and ischaemic zones of heart muscle were clearly differentiated only by PTAH and PAS-navy blue. PAS distinguished normal from glycogen-depleted ischaemic myocardium after only 40-60 min, but this change was also seen in autolyzed tissue.

The electron microscopic localization of nephrotoxic antibodies in isolated glomeruli.

Scanning electron microscopy showed that most glomeruli isolated by sieving from normal and nephrotoxic rats were cleanly decapsulated and undisrupted. An anti-IgG antibody-horesradish peroxidase conjugate was applied to such isolated glomeruli and also to slices of renal cortex which were sebsequently embedded in epoxy resin. Linear staining along the glomerular basement membranes of nephrotoxic rats was evident and subendothelial electron-dense deposits were shown to contain anti-glomerular basement membrane antibody. Whereas the linear reaction was faint and limited to superficial parts of glomeruli in tissue slices, it was intense and present in most regions of all of the isolated glomeruli. Thus, the fine details of the distribution of intraglomerular antibody are more clearly and consistently demonstrated in isolated glomeruli than in kidney slices.

The effects of altered cation balance on the fine structure of hypoxic myocardial cells.

To determine whether the changes in intracellular/extracellular cation balance which develop in ischaemic myocardium are responsible for the fine structural changes seen in such tissue, thin slices of normal canine ventricle were incubated under hypoxic conditions at 37 degrees C and physiological pH in balanced salt solution (BSS), isotonic NaCl and isotonic KCl. Slices from each solution were fixed at 10-120 min intervals and examined by light and electron microscopy. For 60 min, tissue from both NaCl and KCl showed good overall preservation of cell architecture and only mild subcellular alterations including aggregation of nuclear chromatin, disappearance of glycogen granules, and swelling of sarcoplasmic reticulum. Tissue from BSS showed early development of intramitochondrial dense inclusions together with focal contraction-band damage similar to that seen in temporarily ischaemic, re-perfused heart muscle and at the margins of infarcts. These changes thus appear to be promoted by divalent cations. The progressive reversal of monovalent cation balance in an area of permanent and severe ischaemia does not appear to be a major determinant of fine structural change.

The effect of ischaemic injury on the fine structure of canine atrial myocardium.

An experimental model for producing a uniformly and maximally ischaemic segment of atrial myocardium has been devised and used in 23 dogs to investigate the effects of severe ischaemia of up to 6 h duration on the fine structure of atrial myocardial cells. Throughout the first 30 min of ischaemia the cells maintained a fine structure comparable with that of control tissue. In the subsequent 2 h they developed morphological alteration at differing rates, despite their uniform deprivation of blood supply. Even at 90 min the ischaemic tissue showed discontinuous change, with many areas differing little from control, and it was only after 3 h that all cells showed well developed and similar alterations. These included glycogen depletion, marked clumping and margination of nuclear chromatin, and the mitochondrial degeneration typically seen in ischaemically injured ventricle. The changes were very severe after 4 and 6 h of ischaemia, when disruption of cellular membrane systems was also evident. At these times the tissue closely resembled ventricular myocardium made ischaemic for similar intervals, except for the persistence of well-preserved 'specific atrial granules'. Atrial muscle cells therefore develop the fine structural changes associated with ischaemia more slowly than ventricular muscle cells and have a more variable response to the initiation of ischaemic injury.

The potassium/sodium ratio in the demonstration of sudden ischemic cardiac death: a critical appraisal.

The practical value of measuring the ratio of potassium ion (K+) to sodium ion (Na+) in myocardium as an indicator of early inapparent infarction in sudden cardiac death was assessed using a series of 29 human hearts from selected coroner's autopsies together with experimental material from dogs, including infarcts of 5 min to 4 h duration. Samples for electrolyte analysis were derived from a transverse slice of each heart, taken through both ventricles midway between base and apex, all slices being completely subdivided into a numbered sequence of blocks. Ratios were mapped and compared with macroscopic enzyme staining and histological stains for injured muscle. Detailed examination of coronary arteries was performed on all human cases. Measurement of the K+/Na+ ratio did not detect all human cases of proven acute coronary occlusion and did not unequivocally demonstrate experimental infarcts less than 2 h old. Moreover, all ratios fell with increasing duration of autolysis, emphasizing the need for multiple sampling so that each heart may serve as its own control. As a routine test, therefore, the method is both impracticable and unreliable and as previously used has been subject to misinterpretation.

A quantitative study of the sequence of topographical changes in the organ of Corti following acoustic trauma.

The organs of Corti of 30 guinea pigs were examined quantitatively by scanning electron microscopy either immediately or 1, 3, 7 or 14 days after exposure to 3 kHz at 125 dB SPL for 30 min. Lesions (0.1-4.15 mm in length) were observed in 70% of the organs of Corti. There was no significant change in lesion length with recovery from the exposure. Early changes in hair cells consisted of stereocilia abnormalities, predominantly amongst inner hair cells and the first row of outer hair cells. The proportion of affected cells increased towards the centre of lesions, where supporting cells were affected also. Subsequent to exposure, affected hair cells were either lost or remained with stereocilia abnormalities but did not recover. Regions showing supporting cell damage were replaced within 3 days by inner sulcus and Claudius cells. Despite similar changes to stereocilia, inner hair cells were more resistant to necrosis than outer hair cells, suggesting that the nature of stereocilia damage does not necessarily indicate the fate of hair cells.

Pathology medical manpower planning in New Zealand results of 1977 survey.

As part of Medical Manpower Planning in New Zealand, a survey conducted by the New Zealand Society of Pathologists in association with the Royal College of Pathologists of Australia shows that at present there are 116 pathologists practising in New Zealand, a ratio of one to 27 000 population. This is far short of the requirement of 1:20 000, for which an additional 40 pathologists is required now, with an average annual requirement of 11 additional pathologists over the next nine years.

Glomerulonephritis associated with an infected ventriculo-atrial shunt.

We present the case of a seven year old girl with a ventriculo-arterial shunt who developed haematuria and the nephrotic syndrome. Renal biopsy showed a diffuse proliferative glomerulonephritis of mesangiocapillary type. Cultures of blood, cerebrospinal fluid and later, the removed shunt, grew Staphylococcus epidermidis. Her renal function subsequently improved following antibiotic therapy and revision of the shunt.