Recurrent acute renal failure due to a rectal villous adenoma

A case is reported in which a rectal villous adenoma was complicated by severe fluid and electrolyte depletion producing recurrent renal failure. The pathophysiology of the depletion syndrome and its complications are discussed. Successful management by acute haemodialysis and early surgical resection of the tumour is described.     

Construction and characterization of a haploid strain of Saccharomyces cerevisiae that completely lacks all genomic CYH2 sequences

Summary A diploid strain of the yeast Saccharomyces cerevisiae has been constructed that has one copy of the ribosomal protein gene CYH2 completely deleted and replaced with the TRP1 gene using the method of Rothstein (1983). There are only small differences in growth rate and no detectable difference in steady state level of CYH2 mRNA between the diploid that is heterozygous for the CYH2 deletion and the parent diploid with two normal copies of this gene. This suggests that the diploid must partially compensate for the loss of one CYH2 gene. Tetrad dissection shows that haploid spores lacking the CYH2 gene cannot germinate. The lethality of this deletion can be rescued by a CYH2 cDNA on a low copy vector. Haploids which lack the genomic copy of the CYH2 gene, but contain a plasmid copy of the CYH2 cDNA are able to grow normally. These CYH2 deleted yeast haploids should be useful to analyze mutationally altered CYH2 genes and genes homologous to CYH2 from other organisms without interference from a genomic copy.     

Viscosity and retinal vein thrombosis.

Whole-blood and plasma viscosity with haematological and biochemical investigations were measured in 44 patients with retinal vein occlusion. The patients were subdivided on the basis of fluorescein angiographic findings into: 1. Those with large areas of capillary non-perfusion. 2. Those with small areas of capillary non-perfusion. 3. Those with an intact capillary pattern. Capillary non-perfusion in retinal vein occlusion is associated with a higher morbidity owing to the complications of retinal neovascularization. Significantly higher values of whole-blood viscosity, packed cell volume, and yield stress have been found in patients with capillary non-perfusion than in those without. These differences may be of critical importance during the episode of retinal vein occlusion and suggest an aetiological factor in the development of capillary non-perfusion. Higher whole-blood and plasma viscosity values and plasma fibrinogen levels have also been shown in the whole retinal vein occlusion group compared with a control group of 30 individuals. These differences may be a factor in the development of retinal vein occlusion but their precise role is difficult to evaluate. Further biochemical investigations in the vein occlusion group supported the strong association with arterial disease and suggested a higher incidence of biochemical abnormalities in those patients with capillary non-perfusion.     

Appearance of tyrosine hydroxylase immunoreactivity in the human embryo

Tyrosine hydroxylase was detected immunohistochemically in 3 human fetuses aged 5 1/2-6, 9-10 and 13-14 weeks. In the youngest fetus only the developing sympathetic chains were stained. By 9-10 weeks sympathetic terminals, adrenal medulla, carotid bodies, locus ceruleus, substantia nigra and basal ganglia showed positive reactions. In the oldest fetus a dense sympathetic innervation was present in the ductus venosus. Catecholaminergic neuronal systems, including their terminal axons, are well developed by 2 1/2 months of human gestation. PAP immunohistochemistry has the advantage of being applicable to archival formalin-fixed, paraffin-embedded tissue.     

Interpretation of measured red cell mass and plasma volume in males with elevated venous PCV values

A method of interpretation of red cell mass (RCM) and plasma volume (PV) data is described. The results in 188 males with PCV's over 0.50 places the patients in 4 groups: true (absolute) polycythaemias, relative (low plasma volume) polycythaemias, high normal red cell mass (HNRCM) and ‘physiological variant’. Absolute polycythaemias were increasingly frequent at higher PCV levels but only reached 100% at a PCV of 0.60. They showed an 18% incidence in the lower PCV range of 0.500-0.519. Relative (low PV) polycythaemia was found in 18% of the patients with PCV values in the range 0.500 to 0.599. Although the HNRCM and ‘physiological variant’ types found mainly in the lower PCV ranges they occurred at the 0.54 level. While this method of interpretation of RCM and PV data is perhaps arbitrary, it does provide a basis for the proper study of the common group of patients with raised PCV levels in which classification, course and treatment are uncertain. In addition the findings suggest that both RCM and PV should be measured at all levels of PCV over 0.50; that relative (low PV) polycythaemia is a real entity but less common than sometimes believed; that diuretics do not have a notable part in its causation and that the commom HNRCM, ‘physiological variant’ groups are incompletely understood and require further study.