James L.C. Yong

Calcification of the aortic valve: its progression and grading.

Summary Three hundred and seventy four aortic valves which had been surgically removed over the past five years were studied by routine histology. Most patients were male and over the age of 60 years. There were 3.7% bicuspid valves, 16% valves with evidence of past rheumatic fever and 2.1% with endocarditis. A range of pathological lesions was seen including calcification, chondroid and osseous metaplasia, neovascularization, inflammation and cholesterol deposition. A common lesion was a progressive dystrophic calcification of the valve cusps. This was studied and graded in relationship to the concomitant structural damage. There has been no previously published grading system for this type of pathological change in the aortic valve. Our criteria for the four grades of aortic valve lesion are described. Most patients were found to have lesions of Grades 3 and 4.

The response of the small intestine of the protein-deficient rat to infection with Nippostrongylus brasiliensis

Abstract The intestinal response of the protein-deficient Wistar rat was examined after primary infection with 1500 larvae of Nippostrongylus brasiliensis. Protein-deficient animals failed to expel N. brasiliensis after 15 days at a time when nutritionally normal animals had expelled more than 99% of the worm burden. Morphology of the small intestine of protein-deficient animals before infection showed small villi and crypt hypoplasia, followed after infection by sustained crypt hyperplasia and increased mitotic index of crypts. Protein deficiency was associated with fewer mucosal mast cells, goblet cells and intraepithelial lymphocytes. There was an impaired response of mucosal mast cells and goblet cells to infection. This could explain the deficiency of worm expulsion in these protein-deficient animals.

PROGRESSION FROM GOODPASTURE'S DISEASE TO MEMBRANOUS GLOMERULONEPHRITIS

&NA; An unusual case of a patient with Goodpastures disease presenting with hemoptysis, severe iron deficiency anemia and microscopic hematuria and proteinuria is described. Both circulating and tissue anti‐glomerular basement membrane (GBM) antibodies were present, and renal function remained normal throughout. Immunosuppressive therapy was given for subclinical pulmonary hemorrhage with successful resolution of anemia and disappearance of the circulating anti‐GBM antibody. Nine months after presentation he developed nephrotic range proteinuria and a repeat renal biopsy revealed membranous glomerulonephritis with no evidence of his original disease. Both the Goodpastures associated HLA‐DR2 and the membranous associated HLA‐DR3 class II antigens were present. The association of antibody mediated and immune complex glomerulonephritis is discussed. The simultaneous presence of HLA‐DR2 and HLA‐DR3 may predispose to this association.

Early Myocardial Fibrosis is Associated with Depletion of Vasoactive Intestinal Peptide in Rat Heart

In this study we sought to determine whether early myocardial fibrosis is associated with depletion of vasoactive intestinal peptide (VIP) in the heart, thereby suggesting a possible pathogenetic role for depletion of myocardial VIP levels in the development of fibrosis in the heart. Spontaneously hypertensive rats (SHRs) and normotensive control Wistar‐Kyoto rats (WKYs) were assigned randomly to low, intermediate or high sodium diets and their blood pressure was recorded twice weekly for 4 weeks. At the end of this period the rats were anaesthetised, blood was sampled for plasma VIP concentration and the hearts were harvested for histology and determination of the concentration of VIP in the heart. The degree of myocardial fibrosis increased with increasing dietary sodium intake in both the WKYs (P < 0.001) and the SHRs (P < 0.01). Myocardial VIP concentration decreased with increasing dietary sodium intake in the WKYs (P < 0.01) and in the SHRs (P < 0.01). There was a negative correlation between myocardial VIP concentration and the degree of myocardial fibrosis in both the WKYs (P < 0.0005) and the SHRs (P < 0.005). Dietary sodium intake induces myocardial fibrosis in a dose‐dependent manner. Further, in early myocardial fibrosis resulting from increasing dietary sodium intake in both normotensive and hypertensive rats the concentration of VIP in the heart was negatively correlated with the degree of fibrosis. This suggests a possible role for depletion of VIP in the myocardium in the pathogenesis of myocardial fibrosis.

A practical approach to the diagnosis of renal disease by biopsy

&NA; The pathologist has an important role in the diagnosis and monitoring of renal disease. However, for optimal useful information to be derived from renal biopsy specimens, certain guidelines must be adhered to and these are enunciated here. The 3 avenues of observation of renal biopsies viz. light microscopy, immunofluorescence and electron microscopy, all have important roles to play and give differing data which informs the diagnosis for the renal biopsy report. The relative emphasis on each of these modalities of investigation will vary depending upon the situation in which the renal biopsy is performed. The methods used here have been shown to be effective in practice over a period of 20 yrs. Although there may be variations in methodology from centre to centre, the general background aims and principles remain the same. The emphasis in this paper has been on common practical aspects of renal biopsies. Much of the practical information concerning renal biopsies, which is brought together here, is otherwise scattered and not readily available. The aim of this article is to allow the reader to understand the rationale for the steps that are involved in renal biopsy diagnosis.

A study of parathyroid hyperplasia in chronic renal failure

&NA; Specimens removed at parathyroidectomy from 41 patients with chronic renal failure, 12 patients with parathyroid adenomas and parathyroid glands from 24 autopsies were studied by light microscopy, immunohistochemistry and electron microscopy. The morphological abnormalities were correlated with clinical data obtained from patients medical records. Glandular enlargement in chronic renal failure, primarily due to parenchymal cell hyperplasia, was as much as 20 times the normal in contrast to 40 times the normal cases of adenomas. Glandular hyperplasia was mostly due to an increase in the number of chief cells and to a lesser extent increase in the number of oxyphil cells, transitional oxyphil cells and water‐clear cells. There was a corresponding reduction in fat and intracellular lipid content. There were differences in the overall morphology of normal, hyperplastic and adenomatous glands. The clear histological distinction between hyperplastic and adenomatous glands was at times difficult. There was no correlation between the extent of hyperplasia, the cause of renal failure, duration of chronic renal failure, levels of serum calcium, phosphate or parathyroid hormone. Immunohistochemical studies showed that all 3 types of cells contained parathyroid hormone but in hyperplastic and adenomatous glands there was a reduction in parathyroid hormone and chromogranin A staining. There were no specific ultrastructural abnormalities which would distinguish between hyperplastic and adenomatous glands.

The significance of cerebral mantle thickness in fetal ventriculomegaly at autopsy

Aims: To confirm the validity of the method of diagnosing fetal ventriculomegaly at autopsy by measuring cerebral mantle thickness at the frontal lobe and to further evaluate whether taking three measurements at three separate sites is even more reliable. Methods: The thickness of the cerebral mantle was measured at three sites: the frontal lobe, posterior‐frontal lobe and occipital lobe, in 10 human fetuses which were clinically diagnosed by ultrasound to have ventriculomegaly, and in 120 control fetuses. Most fetuses were obtained during the second trimester. The mantle thicknesses were charted against foot length and crown–rump length in each case. Results: Fetal cerebral mantle thickness was reduced in the three sites examined in eight of ten fetuses with a pre‐autopsy diagnosis of ventriculomegaly. The mantle thickness was in the normal range in a growth‐restricted fetus of 19 weeks gestational age with trisomy 21, mild ventriculomegaly, hydrops and cerebral oedema, when correlated with crown–rump and foot lengths. In a 32‐week growth‐retarded fetus with a prenatal ultrasound diagnosis of ventriculomegaly, cerebral mantle thickness was also within the normal range relative to crown–rump and foot lengths. Conclusion: Measurement at autopsy of cerebral mantle thickness is a reproducible and reliable method of confirming the diagnosis of ventriculomegaly in second trimester fetuses. Fetal cerebral mantle thickness measurement taken at the three sites must be correlated with crown–rump and foot length. In most cases where ventriculomegaly was established, the mantle thickness was reduced in fetuses in all three sites examined. The relative thickness of the cerebral mantle in different areas was often abnormal in the presence of ventriculomegaly. Our study of small numbers of cases also suggested that the method of measurement may not be reliable in some cases where there is only mild ventriculomegaly, cerebral oedema or growth retardation.

Neurocysticercosis: a report of four cases

&NA; Cysticercosis is an uncommon disease in Australia. Only 4 cases of neurocysticercosis were found in our hospital with an active neurosurgical service over a 10 yr period. All 4 cases were migrants, 3 from South America and one from Cyprus. Epilepsy, aseptic meningitis and raised intracranial pressure were the common symptoms. Although the cerebral lesions were seen on CT scans, misinterpretation of the X-ray appearances readily occurs and the diagnosis can only be confirmed by histopathological examination of tissues. The pathological features are described including electron microscopy of one case. The cysticercus has a unique ultrastructure which is most helpful in establishing the diagnosis in cases where tissue sample is small and light microscopy is difficult. Neurocysticercosis can masquerade as a glioma or other space occupying lesion or aseptic meningitis. This condition should be considered in obscure neurological syndromes in migrants from affected regions of the world.

Applications of monoclonal anti-human inhibin α subunit in endometrial curettings

Aims: Using archival material, we studied the immunoreactivity and utility of monoclonal anti‐human inhibin α subunit in the identification of chorionic villi (CV) and trophoblastic subpopulations in endometrial curettings (EC) from patients who had intra‐uterine, ectopic, molar and, particularly, probable intra‐uterine pregnancies. We also compared its expression with those of &bgr;HCG, HPL and CAM 5.2. Methods: The four groups of EC investigated included: Group 1, 15 patients with intra‐uterine pregnancies (IUP); Group 2, 15 patients with tubal pregnancies (TP); Group 3, 15 patients with hydatidiform moles (HM); and Group 4, 20 patients with purported history of intra‐uterine pregnancies (PIUP). Positive and negative control cases were from Groups 1 and 3 and Group 2, respectively. The test cases were from Group 4. Immunohistochemistry was performed on each case testing for expression of inhibin α, &bgr;HCG, HPL and CAM 5.2. Results: Trophoblastic populations, which included syncytiotrophoblast (ST), cytotrophoblast (CT) and intermediate trophoblast (IT), were absent in all 15 negative control cases (Group 2). The 30 positive control cases (Groups 1 and 3) revealed the following: (a) ST, CT and IT were identified in all cases and were positive for CAM 5.2, (b) inhibin α, &bgr;HCG and HPL (except one case) were reactive for all cases with ST, but not CT, and (c) IT positivity for &bgr;HCG, HPL and inhibin α was 67, 80‐93 and 100%, respectively. From the 20 test cases (Group 4), the findings were: (a) CT was absent in all cases, (b) scattered ST cells, which were identified only in 10 cases, were positive for all antibodies, (c) scattered IT cells were present in 17 cases and showed 100% CAM 5.2 positivity, and (d) IT positivity for &bgr;HCG, inhibin α and HPL was 58.8% (10/17), 76.5% (13/17) and 82.4% (14/17), respectively. Background staining was observed in 22 of 65 cases (33.8%) stained with &bgr;HCG and HPL; half of these cases came from Group 3. Inhibin α and CAM 5.2 staining did not show this problem. Conclusions: We suggest that inhibin α is a useful antibody in diagnosing IUP and HM and in documenting intra‐uterine gestations in cases with PIUP because it is a sensitive marker in immunolabelling IT and ST. Combined application of inhibin α and CAM 5.2 might be more useful than &bgr;HCG and HPL because the latter showed background staining in one third of the cases.

Detection and measurement of tubulitis in renal allograft rejection

Tubulitis is one of the most reliable signs of acute renal allograft rejection. It occurs when mononuclear cells are localized between the lining tubular epithelial cells with or without disruption of the tubular basement membrane. It has been found that tubulitis takes place predominantly in the regions of the distal convoluted tubules and the cortical collecting system. The image processing tasks are to find the tubule boundaries and to find the relative location of the lymphocytes and epithelial cells and tubule boundaries. The requirement for accuracy applies to determining the relative locations of the lymphocytes and the tubule boundaries. This paper will show how the different sizes and grey values of the lymphocytes and epithelial cells simplify their identification and location. Difficulties in finding the tubule boundaries image processing will be illustrated. It will be shown how proximate location of epithelial cells and the tubule boundary leads to distortion in determination of the calculated boundary. However, in tubulitis the lymphocytes and the tubule boundaries are proximate.In these cases the tubule boundary is adequately resolved and the image processing is satisfactory to determining relativity in location. An adaptive non-linear anisotropic diffusion process is presented for image filtering and segmentation. Multi-layer analysis is used to extract lymphocytes and tubulitis from images. This paper will discuss grading of tissue using the Banff system. The ability to use computer to use computer processing will be argued as obviating problems of reproducability of values for this classification. This paper will also feature discussion of alternative approaches to image processing and provide an assessment of their capability for improving the identification of the tubule boundaries.