The influence of renal papillary urea concentrations and of plasma vasopressin on the urinary prostaglandins E2 and F2 alpha excretion in conscious rats in steady state of urine formation

Urinary excretion rates of PGE2 and PGF2 alpha were measured radioimmunologically in four different groups of unanaesthetized rats: water diuretic rats (I), rats with free access to water (II), water deprived rats (III) and 1.5% saline-loaded rats (IV). The animals were decapitated when steady states of urine formation were ascertained for three to six spontaneously delivered urine portions. Plasma vasopressin was measured radioimmunologically and urea, sodium, potassium concentrations and osmolalities of papillary fluids and of bladder urines were determined. Group means of urinary prostaglandin excretion, papillary urea concentration and logarithmic-transformed plasma vasopressin values vary in parallel for three of the groups (I, II and III) but a dissociation of the effects of papillary urea and vasopressin on the prostaglandin excretion was obtained for group IV. Statistical analyses indicated that the differences in prostaglandin excretion rates between group I and the three other groups are accounted for by the combined effects of vasopressin and papillary urea. The results support the hypothesis that vasopressin stimulates release of arachidonic acid in the papilla and that urea inhibits the trapping of this prostaglandin precursor in cellular lipids. The ratio of urinary PGF2 alpha to PGE2 varied greatly between groups but no consistent dependency on the measured parameters was found.     

Knee injuries: high-resolution MR imaging

Recent technologic advances have made high-resolution magnetic resonance (MR) imaging of the knee a clinical reality. Ten healthy volunteers and 30 patients with suspected knee injuries were imaged using receive-only surface coils and two-dimensional multisection or three-dimensional selective acquisition techniques. Arthroscopic and/or surgical correlation was available in 15 patients. Tears of the cruciate ligament, medial collateral ligament, and meniscus are illustrated. Nonorthogonal views of the anterior cruciate ligament are useful for demonstrating both femoral and tibial attachments in the same section. The posterior cruciate ligament is usually well seen on sagittal views. T2-weighted images are helpful for demonstrating collateral ligament tears and meniscal tears when joint effusion is present. Thin sections (1-5 mm) are necessary to define many meniscal and cruciate tears. High-resolution, thin-section MR imaging can be used to diagnose soft-tissue injuries of the knee and has the potential to become a major imaging method in the evaluation of knee injuries.     

Port-Site Pyoderma Gangrenosum – A Rare Complication of Surgical Trauma

We report a case of pyoderma gangrenosum occurring at the site of a laparoscopic port insertion following laparoscopic inguinal hernia repair.     

Genetic factors affecting the consistency and magnitude of changes in plasma cholesterol in response to dietary challenge

We examined the role of common genetic variation in determining the consistency and magnitude of change in plasma total cholesterol (TC) levels in response to two separate changes from a high-saturated (SFA) to a low-saturated/high-polyunsaturated-fat (PUFA) diet, in a group of free-living healthy men and women. Consistent responders were defined as those whose mean difference in the change in TC was within one SD of the mean for all participants, and the remainder were defined as variable responders. DNA was obtained from 55 individuals and genotype determined at the apolipoprotein (apo) B locus (signal peptide, SP), apoCIII (C1100-T) and lipoprotein lipase (LPL) gene loci (HindIII). In the 38 consistent responders, the apoBSP24 allele was significantly more common than in the 17 individuals with a variable response (0.29 vs. 0.12; p < 0.05). No other polymorphism showed a significant frequency difference between groups. In the group as a whole, the correlation between the change in TC level in response to the first and second dietary change was 0.28 (p = 0.05), but those with one or more apoB SP24 alleles and those with the apoCIII genotype CC had a significantly higher correlation than those with other genotypes (0.46 (p = 0.05) vs. 0.12 (NS) and 0.31 (p = 0.05) vs. 0.02 (NS), respectively). In the group as a whole, mean response left TC 10% higher on the SFA than on the PUFA diet, and neither apoB nor apoCIII genotypes affected the magnitude of this response. However, individuals with the LPL HindIII genotype H+ H+ had a significantly smaller change in mean TC in response to diet than those with one or more H- allele (9.3% vs. 14.4%; p = 0.03). Thus variation at the apoB and apoCIII loci affects the consistency of response to change in dietary fat content, while variation at the LPL gene locus affects magnitude of response.