Renal transport of oxalate: effects of diuretics, uric acid, and calcium

Clearance experiments were performed in the rat to examine the effects of diuretics on the renal transport of oxalate. In addition, the effect of infusing either uric acid or calcium on the renal transport of oxalate was examined. During control periods, the fractional excretion of oxalate (FEOx) averaged 118.0 +/- 2.1%. Acute administration of either chlorothiazide, furosemide, or indanyl-oxyacetic acid (MK-196), a new uricosuric diuretic, resulted in a significant decrease in the FEOx in all groups to 104.8 +/- 2.4%, 111.3 +/- 2.1%, and 108.6 +/- 2.7%, respectively. Infusion of uric acid increased urinary uric acid excretion from 2.41 +/- 0.28 to 4.26 +/- 0.03 micrograms/min/g kidney wt (P less than 0.001) and decreased FEOx to 104.0 +/- 2.4% (P less than 0.001 compared to control). Infusion of calcium chloride increased urinary calcium excretion from 0.10 +/- 0.04 to 0.44 +/- 0.06 micrograms/min/g kidney wt (P less than 0.001) but had no effect on the FEOx which averaged 118.3 +/- 8.3% (P = NS compared to control). These studies show that the acute administration of chlorothiazide, furosemide, or MK-196, as well as increasing urinary uric acid excretion by uric acid infusion, are all associated with a decrease in the FEOx. Acutely increasing urinary calcium excretion, however, had no effect on oxalate transport.

The fate of phage lambda DNA in lambda-infected minicells

The fate of phage lambda DNA in lambda-infected Escherichia coli minicells harboring the plasmid ColE1, and in plasmid-free minicells, were studied. Binding of lambda DNA to the minicell membrane, and formation of the supercoiled covalently-closed circular structure has been demonstrated. Phage infection abolishes plasmid DNA synthesis. Only a very slight, non-replicative lambda DNA synthesis occurs, soon after infection. This synthesis is associated with fragments of lambda DNA arising during, or soon after its penetration.

The effects of ticrynafen in the rat

The effects of ticrynafen, a uricosuric diuretic, were examined utilizing free-flow micropuncture and clearance techniques in the rat. The intravenous infusion of ticrynafen (50 mg/kg body wt/hr) had no effect on glomerular filtration rate, but resulted in significant increases in urine flow from 4.4 +/- 0.7 microliter/min/g kidney wt to 19.2 +/- 2.6 (p less than 0.001); in urinary sodium excretion from 0.14 +/- 0.07 micronEq/min/g kidney wt to 2.35 +/- 0.52 (p less than 0.01); and in urinary urate excretion from 2.8 +/- 0.2 microgram/min/g kidney wt to 4.0 +/- 0.2 (p less than 0.005). There was no change in urinary phosphate excretion. The end-proximal TF/Pinulin ratio was 2.66 +/- 0.18 in control and 2.67 +/- 0.16 in experimental periods (p=NS). In awake animals, ticrynafen administration resulted in a decrease in CH2O from 6.47 +/- 0.12% to 3.50 +/- 0.69 (p less than 0.05), but no change in TCH2O. These studies demonstrate that ticrynafen is a uricosuric and diuretic agent in the rat. The natriuresis appears to derive from an inhibitory action of this agent in the cortical diluting segment of the nephron. In comparison to a related uricosuric diuretic, MK-196, ticrynafen is a less potent agent with respect to both its uricosuric and diuretic properties in the rat.

Coliphage lambda ghosts obtained by osmotic shock or LiCl treatment are devoid of J- and H-gene products

We have proved by acrylamide gel electrophoresis that DNA-free ghosts of bacteriophage lambda obtained by osmotic shock (S-ghosts), or by incubation in 5 M-L-Cl (L-ghosts) do not possess the proteins specified by the genes J and H. Electron microscopy of L-ghosts showed that they are devoid of the whole tail tip, composed of the basal part and the tail fibre. The lack of the J-gene product, which is believed to be the tail fibre, explains why S- and L-ghosts do not adsorb to susceptible bacteria. Our results suggest that the H-gene product, which is modified after translation, is situated in the basal part of the tail.

A new form of automatic watering system for laboratory animals

During a 2 1/2 year trial of this new system no algal or bacterial build-up occurred, and filters were changed only at infrequent intervals. Among the labour-saving advantages of it is that cleaning of the system can be done when cage racks are changed, normally monthly.

Plasma clearance of neostigmine and pyridostigmine in the dog

1 The pharmacokinetics of neostigmine and pyridostigmine was studied in conscious dogs by the use of a cross-over design. 2 Both neostigmine and pyridostigmine were cleared from plasma in a biexponential manner. 3 The apparent volume of distribution of pyridostigmine was invariably greater than that of neostigmine, and its fast disposition half-life was approximately three times longer. 4 The whole body clearance and the urinary elimination of pyridostigmine was approximately twice that of neostigmine. 5 The slow disposition half-life of pyridostigmine was approximately three times longer than that of neostigmine, suggesting that the longer duration of action of pyridostigmine is related to the differential clearance of the two quarternary amines from plasma.

The microbiology of a new recirculatory automatic watering system compared with a conventional automatic system

Continual recirculation and filtration of drinking water prevents the contamination that often mars automatic watering systems by removing algae and fluorescent pseudomonads. Without filtration and recirculation, the algae were clearly visible after 40 days use, and the fluorescent pseudomonad count rose from 10(1) to 10(5) per ml after 72 h use.

Physical measurements of the liver glucocorticoid receptor

Physical measurements were made on the cytosolic form of the liver [3H]dexamethasone receptor. These include a Stokes radius of 3.5 nm, determined by gel filtration, and sedimentation coefficients of 5.1 and 7-8S, by sucrose-density-gradient centrifugation. From these measurements, the following physical properties were calculated: apparent mol. wt. 78000 (the 5.1 S form); D app. 6.1 X 10(-7) cm2-S-1; f/fo 1.25; axial ratio 4.7; these indicate a globular protein. Measurements of sedimentation coefficient of cytosol steroid-receptor complexes previously subjected to various activating conditions gave different values and lead to the conclusion that the mechanism of activation in vitro enabling the steroid-receptor complex to bind to DNA is more complex than simple disaggregation to a uniform size.

Histochemical characteristics and contractile properties of the spinotrapezius muscle in the rat and the mouse

In the spinotrapezius muscle of the rat and the mouse approximately equal proportions of A,B and C fibres are present. The spinotrapezius therefore contains a lower proportion of B fibres than are known to be present in soleus, but a higher proportion than in tibialis anterior. These results are consistent with the functional properties of the muscles, for the values for isometric twitch contraction time, the half relaxation time, and the twitch summation frequency of the spinotrapezius are also intermediate between those of soleus and tibialis anterior. The present experiments support the view that the proportion of B fibres to A and C fibres govern the overall functional characteristics of mammalian muscles.

Blood filter evaluation

Massive blood transfusion and extracorporeal circulation result in bombardment of the small pulmonary arterioles with micro-aggregates which are mainly composed of cellular degradation products, damaged platelets and leukocytes, fibrin strands, portions of cellular membrane and protein precipitates. Such amorphous material can cause patients to die of respiratory insufficiency without underlying chest trauma. Increasing amounts of stored blood are transfused to patients and extracorporeal circulation has become one of the most useful techniques for surgeons. Unfortunately, these procedures are often accompanied by disturbing post-operative consequences. This is because micro-aggregates invade the capillary network of several organs, especially lungs, kidneys, brain and retina. It is why blood filtration has recently gained added interest because of widespread efforts to minimise the number or emboli which are either transfused or reinfused to the patient through the blood return line.

The effect of edrophonium on erythrocyte acetylcholinesterase and neuromuscular function in the rat

1. The relation between the concentration of edrophonium in plasma, inhibition of red cell acetylcholinesterase, and neuromuscular transmission was studied in the rat. 2. In both in vivo and in vitro conditions, red cell acetylcholinesterase activity was predictably related to the concentration of the quaternary amine. 3. After low doses of edrophonium (1.0 mumol/kg) there was a significant correlation between the monophasic potentiation of twitch tension and the plasma concentration of the drug. In contrast, with higher doses of edrophonium (4.0 or 10.0 mumol/kg) a biphasic potentiation of twitch tension was observed; this was only correlated with the plasma concentration of the drug during the secondary decline in neuromuscular facilitation. Subsequent recovery of normal neuromuscular transmission invariably occurred at a constant plasma concentration of edrophonium.

Isolation of coliphage lambda ghosts able to adsorb onto bacterial cells

We have examined three methods of lambda ghost production, starting with the [3H]leucine-labelled phage, purified by CsCl density gradient sedimentation. Ghosts obtained by the osmotic shock or by incubation in 5 M LiCl do not adsorb on bacteria. Ghosts obtained by the treatment with the chelating agent EDTA and purified by CsCl density gradient sedimentation possess well preserved adsorption properties and are virtually free of DNA and infectious phage particles.