Polycentric total knee arthroplasty. A two-year follow-up study

Polycentric total knee arthroplasty provided significant relief of pain in 86 per cent of 500 knees. The independence and activity levels of the patients increased dramatically. The frequency of major complications as reflected by reoperation was 10 per cent in this series. There was a 2.8 per cent deep infection rate. One-third of the infected knees were salvaged and two-thirds required arthrodesis. Loosening of a component was noted in 2.4 per cent. After operation the average range of motion was from 6 to 101 degrees of flexion, for a range of 95 degrees; this was a 5-degree increase over average preoperative motion. Ninety-six per cent of the patients expressed satisfaction with the surgical result.     

Idiopathic membranous glomerulonephritis

The only case of idiopathic membranous glomerulonephritis seen out of 106 nephropathic patients biopsied in the two last years at the C. H. 20 de Noviembre, I.S.S.S.T.E., is reported. Twenty-six showed nephrotic syndrome not associated to systemic disease, including the present case, which gave us an incidence of 3.8% of this entity. We were impressed by the low frequency of this disease, so we made a statistical epidemiological analysis localizing it geographically based on the available medical literature. On comparing the results of these studies we confirmed that this disease is significantly low in our environment.     

Factors influencing rumen fermentation: effect of hydrogen on formation of propionate

The effect of hydrogen on fermentation of lactate, pyruvate, fumarate, and succinate by resting rumen microorganisms has been investigated. Under an atmosphere of nitrogen, lactate was fermented to yield acetate as the major product (85 to 100 mole %) and propionate (0 to 17 mole %) and butyrate (0 to 3%) as secondary products. Under hydrogen, there was increased formation of both propionate and total volatile fatty acids. The amount of propionate increased 4 to 8 times and total volatile fatty acids 2.5 to 3.2 times. Propionate formation was proportional to the hydrogen concentration and reached a maximum at a partial pressure of hydrogen of .2 N/m2. With [2-carbon-14] lactate, propionate was formed via the dicarboxylic acid pathway under both nitrogen or hydrogen. Hydrogen did not affect significantly the fermentation of pyruvate or succinate. With fumarate under hydrogen, propionate and total volatile fatty acids increased 6.8 and 2 times while acetate was unchanged. The mechanism by which hydrogen exerts these effects is discussed in relation to the role of methanogenesis in the rumen.     

The influence of reserpine on the responsiveness to norepinephrine and electrolyte contents of rabbit atria

This study was designed to investigate the relationships between reserpine-induced supersensitivity and electrolyte levels in isolated rabbit atria. Atria from reserpine-treated (1, 3 or 4 mg/kg 24 hr before) and untreated rabbits were placed in an isolated organ bath for determination of dose-response relationships for norepinephrine, or were used for electrolyte assay. Reserpine-treated atria had greater resting and maximum rates of beat than did untreated atria. However, the ED50 concentrations of norepinephrine producing a rate response were similar. Atria pretreated with 1 or 3 mg/kg reserpine were supersensitive to the inotropic effect of norepinephrine. 4 mg/kg reserpine did not induce inotropic supersensitivity. Atrial sodium contents were significantly increased by 3 mg/kg reserpine. Potassium contents were increased by 1 and 4 mg/kg reserpine. Calcium contents were significantly decreased by 4 mg/kg reserpine, while magnesium contents were increased by 1 and 4 mg/kg. Reserpine induced supersensitivity to the inotropic effects of norepinephrine but did not alter the sensitivity to the chronotropic effect of the drug. This supersensitivity may be linked to alterations in the tissue's homeostatic mechanisms for calcium.     

Base pairing and fidelity in codon-anticodon interaction

On the basis of chemical considerations and model building, the Watson-Crick concept of complementary base pairing is extended to a wider range of DNA pairs that A-T and G-C (including A-C, G-T, A-A, G-G and G-A) by invoking imino or enol tautomers (or protonated species) and synisomers. The virtual absence of these additional base pairs from DNA is explained in terms of the low frequency with which these unfavoured forms occur and the two-step mechanism of DNA synthesis, whereby residues are first incorporated by the DNA polymerase and then checked. This base-pairing hypothesis is used to explain the origin, nature and level of spontaneous substitution mutations, their enhancement by base analogues, and the unique effects of certain mutator alleles.     

Protoplasts of Cosmarium as a potential protein source

Cosmarium turpinii, a fast-growing desmid alga, transforms into protoplasts in 4 h when incubated in a mineral medium + 0.4 M mannitol + 0.5% Cellulysin.     

A method of carrying out ECT under anesthesia with relaxants

During EST of schizophrenic (with a prevalent depressive symptomatology) and manic-depressive patients refractory to medicinal therapy, it was possible to find the following conditions. There was a definite advantage in the use of a narcotizing preparation such as epontal with a relaxant listenon compared to a tiopenthal narcosis. This may be due to a short-time narcotic effect of epontal, the absence of postnarcotic symptoms such as expressed apathy, weakness, headaches, which can be observed during 2-3 hours, following tiopenthal narcosis.