A Method for the Investigation of Reticuloendothelial Iron Kinetics in Man

A colloidal suspension of hydrolysed radio-iron of high specific activity has been developed for the investigation of reticuloendothelial (RE) iron kinetics in man. Following intravenous injection this material is cleared rapidly by the RE system and the iron released intn to the endogenous RE iron load, and it has proved possible to measure RE iron release without disturbing the normal iron flow.     

The origin of thrombi in the deep veins of the lower limb: a venographic study

A series of 952 patients was examined by ascending venography; 812 with clinically diagnosed deep vein thrombosis (DVT) (group 1) and 140 with clinical features suggestive of pulmonary embolism (group 2). Thrombus was demonstrated in 401 (49.4 per cent) of group 1 and in 74 (53 per cent) of group 2 patients. A total of 535 limbs contained thrombus. In 493 (92 per cent) thrombus was present in the calf with either no further clot, or clot in continuity with that in more proximal veins. In the remaining 42 legs (8 per cent) thrombus either originated from multiple discontinuous sites in the legs and pelvis, or in proximal major veins without concomitant calf involvement. The clinical implications of these findings are discussed.     

Fluid absorption with and without sodium in isolated perfused snake proximal tubules

Net fluid absorption (JV) was studied in isolated, perfused snake (Thamnophis spp.) proximal renal tubules. With standard (150 mmol/liter Na+) bicarbonate-buffered Ringer in perfusate and standard Ringer plus dextran (4 g/100 ml) in bath, JV was about 0.9 nl min-1 mm-1. Removing dextran from bath reduced JV by about 20 percent. When sodium in perfusate was replaced with choline JV approached zero. However, when sodium in bath as well as perfusate was replaced with choline, JV returned to control level. Results were the same when sodium was replaced with tetramethyl-ammonium, sodium chloride was replaced with sucrose or lactose, or chloride was replaced with methyl sulfate. In contrast, replacing sodium in perfusate or in both perfusate and bath with lithium did not reduce JV. Fluid absorption was always isosmotic. Replacing bicarbonate with phosphate or Tris in sodium-containing media had no effect on JV, but the presence of buffer in sodium-free or low-chloride media may have been important for JV. Reducing temperature 10 degrees C reduced JV by about 35 percent with either sodium chloride or sucrose in both perfusate and bath. The results indicate that isosmotic fluid absorption can occur when lithium is substituted for sodium or when some other substitution is made for sodium, chloride, or both in perfusate and bath simultaneously.     

Synovial regeneration and articular cartilage changes after synovectomy in normal and steroid-treated rabbits.

Ltttle is known of the effects of synovectomy on articular cartilage. In order to investigate this matter, anterior synovectomy of the knee was performed in thirty-five normal adult rabbits and in thirty-five which were given 25 milligrams of hydrocortisone intramuscularly each week afterwards. The animals were killed at intervals from four to 110 days after synovectomy. Histological examination of the regenerating synovium in both groups showed complete structural and functional regeneration by eighty days in the first group and a delay in regeneration in the steroid group. Sulphur autoradiographs of the articular cartilage of femoral and tibial condyles revealed surface fibrillation and chondrocyte death in 23 per cent of normal knees after eighty days but only 1.8 per cent of knees of animals receiving hydrocortisone. Thus synovectomy in a healthy joint may have an unfavourable effect on the physiology of cartilage by alteration of synovial composition and hyaluronate content in normal joints. Systemically-administered hydrocortisone may reduce this harmful effect in normal cartilage.     

Serum inorganic fluoride levels in obese patients during and after enflurane anesthesia

Serum ionic fluoride levels in 24 markedly obese patients (127.6 +/- 6.0 kg) and seven nonobese control subjects (67.3 +/- 1.2 kg) were compared during and following enflurane anesthesia (less than 2.0 MAC hr). Peak serum fluoride levels were higher (28.0 +/- 1.9 vs 17.3 +/- 1.3 micrometers/L, p less than 0.01) and the rate at which fluoride levels increased was more rapid (slope 5.6 vs 2.5 micrometers/L/hr) in obese patients than in control patients. No clinical evidence of nephrotoxicity was found in either group. Vasopressin resistance tests were not performed, and thus it is inknown whether subclinical nephrotoxicity occurred in either study group. Possible reasons for increased enflurane metabolism in obesity are discussed. These possibilities include differences in fluoride ion kinetics, hepatic delivery and penetration of volatile anesthetics, and altered hepatic microsomal enzyme activity. Obesity rather than weight is an important determinant of anesthetic biotransformation.     

Randomised controlled trial of vancomycin for pseudomembranous colitis and postoperative diarrhoea.

The efficacy of vancomycin in pseudomembranous colitis was assessed in a prospective randomised controlled trial. Forty-four patients with postoperative diarrhoea were allocated to five days' treatment with either 125 mg vancomycin six-hourly or a placebo. Sixteen patients had high titres of the neutralised faecal toxin characteristic of pseudomembranous colitis; nine received vancomycin and seven placebo. At the end of treatment faecal toxins were present in one patient given vancomycin compared with five of the controls. Vancomycin caused the disappearance of Clostridum difficile from the stool in all except one patient, whereas toxicogenic strains of Cl difficile persisted in all but one of the controls. Histological evidence of psuedomembranous colitis had disappeared by the end of treatment in six out of seven patients given vancomycin compared with only one out of seven patients given vancomycin compared with only one out of five patients given placebo. In patients with faecal toxins bowel habit had returned to normal in seven of the vancomycin group compared with only one of the controls, but there was no significant difference in clinical response among patients without faecaal toxins. The results suggest that vancomycin eliminates toxin-producing Cl difficile from the colon and is associated with rapid clinical and histological improvement in patients with pseudomembranous colitis.     

The toad's (Bufo marinus) lens and urinary bladder as mural membranes: a comparison

The function of the toad's (Bufo marinus) crystalline lens and urinary bladder as mural membranes have been compared. Both have a layer of epithelial cells which are an important factor in controlling their permeability. The composition of the tissues and their bathing fluids have been compared. There is an electrical P.D. short-circuit current (SCC) and transmural active sodium transport across both tissues but these are less in the lens. The electrical resistance and permeability to potassium are similar in both tissues. Unidirectional water movement is much less in the lens probably reflecting its greater thickness. Oxygen consumption of the lens is less than 3% than in the bladder. The SCC is depressed by ouabain and iodoacetate in both tissues. DNP, ethacrynic acid and amiloride, are only effective on the bladder. Aldosterone, insulin and ADH stimulate SCC across the urinary bladder but it is not known if they have any such action on the lens.