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, , 38-50. Coronary perfusion and hypothermia both have disadvantages, and excellent clinical results are obtained without them, though short operations, spontaneous cooling of unperfused hearts, hyperglycaemia, heparinization, and young and cyanotic subjects may allow more tolerance of ischaemia. Functional, macroscopic, histological, ultrastructural, chemical, and metabolic evidence of the inadvisability of ischaemia, especially of hypertrophied hearts, abounds, though statistical support and histochemical proof are lacking. Isovolumic function tests permit accurate assessment of compliance. Succinic dehydrogenase distribution is the most relevant enzyme assay of myocardial transport; freed phospholipids indicate cellular membrane disorganization. Adenosinetriphosphate response of myosin (myocardial ATP ase) is shown quantitatively by change of birefringence. Ventricular oedema may be detected by changes in weight. These tests were used to compare continuous normothermic, intermittent hypothermic, and intermittent normothermic perfusion over two hours in isolated, cross-perfused canine hearts. Isolated hearts are very sensitive to imperfections of maintenance, but cross-perfusion minimizes perfusion-induced deterioration. Normothermic continuously perfused hearts performed significantly better than intermittently perfused hearts, among which cooled hearts functioned better than normothermic hearts after two hours. Succinic dehydrogenase and acid haematein tests showed significant benefit from cooling during intermittent perfusion. The experimental preparation and techniques of assessment proved sensitive enough to demonstrate these differences, though cooling preserved cellular enzymes better than it did function. This work gives histochemical and statistical support to existing evidence that intermittent ischaemia for two hours can be ameliorated by moderate hypothermia but is not as effective for myocardial maintenance as constant perfusion with normal blood. [ABSTRACT FROM PUBLISHER]

By varying the time of hydrolysis for the Feulgen reaction, done under conditions that protect the backbone of the DNA, it is possible to distinguish three species of DNA that are characterised by their lability to acid hydrolysis. The most labile DNA was found, in greatest proportions, in malignant cells; this may be helpful in diagnostic cytology. The fact that the cytologically normal cells, in grade V smears, also show this labile DNA may well facilitate cytological screening even in those smears that contain very few neoplastic cells. [ABSTRACT FROM PUBLISHER]

Lysosomal naphthylamidase activity has been measured microdensitometrically in cells in samples obtained by cervical and vaginal irrigation from 22 cases cytologically graded I and II, 28 graded III (moderate to severe dysplasia), 22 graded IV (carcinoma in situ), and 15 cases (grade V) of invasive carcinoma. There was a statistically significant difference in this activity in the cells from cases of grade V as against those in the relatively normal samples (grades I and II; p < 0.001) and as against those of grade IV (p < 0.005). The method is sufficiently robust for routine use provided that it is recognised that elevated activities can be found as a consequence of other factors such as previous surgical intervention and infection with herpes simplex. [ABSTRACT FROM PUBLISHER]

Parietal cell antibodies (PCA) arc found in up to 90% of sera from pernicious anaemia patients but it is often stated that they could represent an epiphenomenon without being directly responsible for the achlorhydria. In the present studies a direct effect of these antibodies on the secretory function of gastric acid-secreting cells has been demonstrated in two different experimental systems. In one set of experiments IgGs containing PCA activity were shown to inhibit acid secretion specifically in the living gastric mucosa of the bull frog suspended as a diaphragm between two chambers. The other system demonstrated their inhibition of carbonic anhydrase activity in a cytochemical bioassay for human G17-gastrin, suggesting a blocking effect on the gastrin receptors in the canalicular microvilli or the cell membrane. These experiments suggest a direct pathogenic role for PCA in autoimmune fundal gastritis and in pernicious anaemia. [ABSTRACT FROM AUTHOR]

Specimens of human rheumatoid and nonrheumatoid synovial lining were maintained in nonproliferative organ culture for 20 hours. The culture fluids were then assayed for prostaglandin E(2) (PGE(2)), thromboxane B(2) (TXB(2)), and 6-keto-prostaglandin F(1alpha) (6-keto-PGF(1alpha)) by specific radioimmunoassay. The presence of each of these substances was confirmed by gas chromatography and mass spectrometry. Rheumatoid tissue produced significantly more of each cyclo-oxygenase product than nonrheumatoid tissue. [ABSTRACT FROM AUTHOR]