Gastrointestinal lymphoma

The gastrointestinal tract is the commonest site for primary extranodal malignant lymphoma. Despite this, gastrointestinal lymphomas are rare and present diagnostic and conceptual challenges. Principal among these are the differential diagnoses of malignant lymphoma and carcinoma and malignant lymphoma and pseudolymphoma, especially in the stomach; the nature of Mediterranean lymphoma and of the lymphoma complicating celiac disease; and the conceptual basis for differentiation of follicular centre cell lymphomas in the intestine.     

Effect of D-tryptophan on hemolysin production in Vibrio parahaemolyticus

Production of the Kanagawa hemolysin by a strain of Vibrio parahaemolyticus isolated from a gastroenteritis patient was found to correlate with the presence in cell lysates of two unidentified compounds, designated X and Y. The two compounds were present in cell lysates of the organism grown in peptone at the optimal pH for hemolysin synthesis but were not present when cell lysates were grown in peptone at a constant pH of 8.0. They were also absent in cells grown in synthetic medium at pH 6.2 without the addition of D-tryptophan, a condition under which hemolysin is not produced. Both X and Y were present intracellularly only from the time that D-tryptophan was added to synthetic medium, a known method of inducing hemolysin synthesis.     

Mouse homologues of the human AZF candidate gene RBM are expressed in spermatogonia and spermatids, and map to a Y chromosome deletion interval associated with a high incidence of sperm abnormalities

An RNA-binding motif (RBM) gene family has been identified on the human Y chromosome that maps to the same deletion interval as the 'azoospermia factor' (AZF). We have identified the homologous gene family (Rbm) on the mouse Y with a view to investigating the proposal that this gene family plays a role in spermatogenesis. At least 25 and probably >50 copies of Rbm are present on the mouse Y chromosome short arm located between Sry and the centromere. As in the human, a role in spermatogenesis is indicated by a germ cell-specific pattern of expression in the testis, but there are distinct differences in the pattern of expression between the two species. Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are female due to a position effect resulting in non-expression of Sry ; sex-reversing such mice with an Sry transgene produces males with a high incidence of abnormal sperm, making this the third deletion interval on the mouse Y that affects some aspect of spermatogenesis. Most of the copies of Rbm map to this deletion interval, and the Yd1males have markedly reduced Rbm expression, suggesting that RBM deficiency may be responsible for, or contribute to, the abnormal sperm development. In man, deletion of the functional copies of RBM is associated with meiotic arrest rather than sperm anomalies; however, the different effects of deletion are consistent with the differences in expression between the two species.      

Sequencing of the alpha-synuclein gene in a large series of cases of familial Parkinson's disease fails to reveal any further mutations. The European Consortium on Genetic Susceptibility in Parkinson's Disease (GSPD)

A mutation in exon 4 of the human alpha-synuclein gene was reported recently in four families with autosomal dominant Parkinson's disease (PD). In order to examine whether mutations in this exon or elsewhere in the gene are common in familial PD, all seven exons of the alpha- synuclein gene were amplified by PCR from index cases of 30 European and American Caucasian kindreds affected with autosomal dominant PD. Each product was sequenced directly and examined for mutations in the open reading frame. No mutations were found in any of the samples examined. We conclude that the A53T change described in the alpha- synuclein gene is a rare cause of PD or may even be a rare variant. Mutations in the regulatory or intronic regions of the gene were not excluded by this study.      

The effect on total renal and tubular function and plasma renin of a moderate isotonic saline load in rats anesthetized with amytal and inactin.

The renal effects of i.v. saline loading equal to 1% body weight (b.wt.) were studied in 2 groups of rats: group I was anesthetized with Amytal (15 mg/100 g b.wt. plus supplementary doses), group II with Inactin (12.5-15.0 mg/100 g b.wt.). In group I the saline load caused an increase in urine flow (+92%), solute excretion (+67%), inulin clearance (CIN) (+24%), PAH clearance (+31%) and absolute proximal reabsorption rate (+27%). Proximal fractional reabsorption and filtration fraction (FF) remained unchanged, while plasma oncotic pressure (COP) decreased by 10%. Plasma renin fell and there was an inverse relationship between renin concentration and proximal reabsorption rate. In group II urine flow and solute excretion increased after saline (+85% and 110%, respectively); CIN and absolute proximal reabsorption rate was lower than in group I and failed to increase after saline. Proximal fractional reabsorption was also lower and decreased after saline. COP as well as renin decreased as in group I, but no relationship between renin concentration and proximal reabsorption rate could be demonstrated. The data indicate that Inactin depresses both resting proximal tubular reabsorptive capacity and the tubular response to a physiological volume expansion. The results are compatible with the hypothesis that the renin-angiotensin system is significantly involved in regulation of proximal tubular function, while they are incompatible with the idea that peritubular COP plays any major role in this adjustment.     

Follicular fluid renin concentration and IVF outcome

Total renin protein concentration (TRC) was measured in stored follicular fluid (FF) samples from 42 women. Samples were selected according to their origin from follicles either without recovered ova ('empty', n = 38) or fertilized but with failed implantation ('failed', n = 36) or successful deliveries ('deliveries', n = 71). Ratios of number of embryos transferred to number of infants delivered were 2:1, 3:1 or 4:2 but 1:1 was not available. Non-parametric testing was applied to FF-TRC, volume and outcome. TRC was significantly higher in the delivery than the failed (P = 0.001) or empty (P = 0.002) categories. Assuming that the range of renin in failed follicles can identify the sub-population of unsuccessful follicles in the delivery category, then elevated FF-TRC was clearly associated with successful outcome. For individual women, the odds of infant delivery increased 17-fold as a function of average FF-TRC between 10,000 and 25,000 microIU/ml. For failed and delivery but not empty follicles, higher renin levels occurred in the smaller follicles, consistent with a burst of renin synthesis associated with the presence of an oocyte. The results suggest that FF-TRC relates to ovum viability with ovarian hyperstimulation and may have predictive use in IVF programmes.     

Recombination aneusomy of chromosome 5 associated with multiple severe congenital malformations

A male infant is described in whom congenital anomalies were recognized prenatally by ultrasound examination. The infant was delivered following spontaneous labor and died approximately 15 min after birth. An autopsy revealed major anomalies in the central nervous system (holoprosencephaly with premaxillary agenesis), the gastrointestinal system (esophageal atresia) and the heart (tetralogy of Fallot). Chromosomal studies revealed recombinant chromosome 5 [46,XY, rec(5), dup q, inv(5)(p15q32)], resulting in partial trisomy 5q and partial monosomy 5p. Cytogenetic investigation of the family revealed a pericentric inversion of chromosome 5 in the father and paternal grandmother, 46,XY (and XX, respectively,) inv(5)(p15q32). The congenital anomalies in this infant are more extensive and severe than previously reported in cases of recombination aneusomy involving chromosome 5.     

Highly Polymorphic Domains of the Human Serum Amyloid A (SAA) Gene GSAA1

The DNA of the human serum amyloid A (SAA) gene GSAA1 contains several repetitive regions within its introns. We have studied length variations at one such region in the 2nd intron by selective amplification using the polymerase chain reaction (PCR) and defined oligonucleotide primers. The lengths of the repetitive regions frequently differ between individual chromosomes and can be transmitted as Mendelian markers, making them useful for genetic linkage analysis.