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At least 37 records · Page 2Linked to original sources
PubMed1979

[Bilateral selective renal angiography--a procedure worth while? Report of the incidence of bilateral space-occupying lesions of the kidney in 2721 selective renal angiographies (author's transl)].

Since surgeons can save part of one kidney either by partial resection or reimplantation following "workbench" surgery, it has become increasingly important for the radiologist to demonstrate bilateral space-occupying lesions of the kidneys by bilateral selective angiography, magnification technique and computerized tomography of the kidneys. Fine-needle puncture of the kidney is an important additive technique to solve differential diagnostic problems of avascular, space-occupying renal lesions. Moreover it is a great comfort to the surgeon to know the appearance of both kidneys and may also modify the planned surgical procedure considerably. The incidence of 93 cases of bilateral space occupying lesions of the kidneys, diagnosed in 2721 selective renal angiographies over a period of 13 years, suggests that these entities are more frequent than previously thought.

Adult↗
PubMed1977

Selective amplification of genes on the R plasmid, NR1, in Proteus mirabilis: an example of the induction of selective gene amplification.

The drug-resistance plasmid, NR1, is a 37-micron circular DNA molecule that contains two components: the resistance transfer factor (29 micron) carrying the transfer genes and the genes for tetracycline resistance, and the r-determinant (8 micron) carrying the genes for resistance to several other antibiotics including chloramphenicol (Cm). In Proteus mirabilis, these two components are capable of independent replication, or they may replicate as a composite molecule. When cells of P. mirabilis containing NR1 are cultured in medium containing Cm at 250 microgram/ml a growth lag of 20-35 hr ensues. During this lag, Cm induces the selective amplification of the r-determinant, including the gene for resistance to Cm. The amplification results from the excision of the r-determinant from the R plasmid, the independent replication of the r-determinant to give polymeric as well as monomeric r-determinants, and the eventual reintegration of multiple tandem copies of the r-determinant with the resistance transfer factor to form a new R plasmid with multiple copies of the r-determinant. This mechanism represents a new level of control of gene expression in bacterial systems--namely, the induction of selective gene amplification.

Cell Division↗
PubMed1979

Relative productivity of five selective plating agars for the recovery of Salmonella from selected food types.

During a 3-year period, the relative productivity of brilliant green (BG), bismuth sulfite (BS), Salmonella-Shigella (SS), Hektoen enteric (HE), and xylose lysine, desoxycholate (XLD) agars for recovering Salmonella from 9 food types was determined. Following pre-enrichment, selective enrichment of food samples in tetrathionate broth followed by streaking to BS agar was the single most productive selective enrichment broth-agar combination for recovery of Salmonella in 5 of these food types. A study of the performance of these 5 agars used individually and in various combinations, showed that none of the 5 agars used individually nor any of the possible paired combinations of these agars could be used to satisfactorily detect Salmonella in the 9 food types. The use of all 5 agars was not necessary because one combination of 4 agars (BG, BS, HE, and XLD) recoverd 100% of the Salmonella isolates, as compared with the number of Salmonella isolates recovered by the 5-agar combination, in each food category. This particular 4-agar combination, along with two 3-agar combinations (BG, BS, and XLD agars, and BS, HE, and XLD agars), were each able to recover more Salmonella isolates, than the combination of BG, BS, and SS agars, the combination currently recommended by the AOAC. Finally, the relative costs of using these agars, singly and in various combinations, were determined.

Agar↗
PubMed1979

Non-selective and selective beta-1-adrenoceptor blocking agents in the treatment of hyperthyroidism.

Treatment for one month with propranolol or atenolol, a selective beta-1-adrenoceptor blocking agent, was evaluated in 20 hyperthyroid patients. The patients improved to the same extent on either drug, as shown by a clinical diagnostic index. Basal metabolic rate decreased by 11% during both treatments, while it was unchanged in seven untreated hyperthyroid controls. Thyroxine concentration did not change during any treatment. During propranolol treatment T3 decreased from 4.6 to 3.9 nmol/l, while no changes were observed during atenolol treatment or in the control group. No significant changes were seen in free T4, free T3 or rT3 concentrations on any treatment, although free T3 was observed to decrease slightly during propranolol treatment. Thus, the improvement of the clinical symptoms of hyperthyroidism cannot be explained by diminished thyroid hormone concentrations in serum, since the reduction was small during propranolol and absent during atenolol treatment.

Adolescent↗
PubMed1977

Selective and non-selective beta-blockade in renin release.

The effects of two beta-adrenergic receptor blocking drugs, the non-selective propranolol and the beta1selective metoprolol, were studied on hemodynamics and plasma renin activity (PRA) of healthy volunteers in an ergometric exercise test. Oral doses of 160 mg of propranolol and 200 mg of metoprolol were tested against placebo. The drug plasma concentrations were determined. Heart rate and systolic blood pressure were equal and significantly lower during treatment with both active drugs when compared to placebo. The effect of drugs on exercise heart rate was correlated with the logarithm of drug plasma concentration with both propranolol and metoprolol. Propranolol, but not metoprolol, decreased the basal level of PRA. The ergometric exercise induced a significant rise in PRA after placebo but this increase was partially inhibited by the both active drugs. On the basis of these findings it is suggested that in man the basal level of PRA could be decreased mainly by blocking the beta2-adrenoceptors. Instead the exercise induced increase of PRA could be inhibited by blocking the beta1-adrenergic receptors.

Administration, Oral↗
PubMed1977

Observations in man of hypoglycaemia during selective and non-selective beta-blockade.

The acute hypoglycaemic reaction is accompanied by a rise in systolic and a slight fall in diastolic blood pressure and a tachycardia. In contrast, during beta-blockade with propranolol there is a rise of both systolic and diastolic blood pressures and bradycardia. Restoration of blood glucose to normal is delayed. With metoprolol there is a lesser increase in diastolic blood pressure and a slight tachycardia. Restoration of the blood glucose to normal is little delayed. When patients liable to hypoglycaemia require a beta-blocking agent, it is suggested that a selective blocker such as metoprolol should be used.

Acute Disease↗
PubMed1976

Studies on the comparative pharmacology and selective toxicity of tricaine methanesulfonate: metabolism as a basis of the selective toxicity in poikilotherms.

Tricaine methanesulfonate, administered at a dose of 150 mg/kg i.p., produced a flaccid paralysis and loss of the righting reflex in a number of poikilothermic species including the frog. Leopard frogs (Rana pipiens) given 150 mg/kg i.p. regained the righting reflex at 113 +/- 28 (S.D.) minutes after injection. A similar dose administered i.p. to mice produced no apparent pharmacological response. The biological half-life (T1/2) of tricaine in frogs (R. pipiens) was about 70 minutes at temperatures of 23 and 37.5 degrees C; at 7 degrees C the T1/2 was 309 minutes. In contrast, in the mouse the drug was metabolized so rapidly that 5 minutes after i.p. administration of 5 mg of tricaine methanesulfonate (250 mg/kg) none of the unchanged drug could be recovered from the animal. It was, however, recovered quantitatively as Bratton-Marshall reacting metabolites, including m-aminobenzoic acid. Incubations of tricaine with serum from bullfrogs, mice and humans indicated that the drug was metabolized to m-aminobenzoic acid with an apparent Km of 3 X 10(-3) M for the reaction. The Vmax for incubations of the drug with bullfrog and human serum was 40 nmol/min/ml of serum, whereas in mouse serum it was 93 nmol/min/ml of serum. In vitro studies with liver homogenates showed that mouse liver metabolized tricaine 39 times more rapidly than frog liver. We conclude, therefore, that the liver is the major site of tricaine hydrolysis in mammals and that the selective toxicity of tricaine for poikilotherms is a consequence of their slower rate of hepatic biotransformation of tricaine.

Aminobenzoates↗
PubMed1976

Critical evaluation of the diagnostic value of systolic time intervals in the diagnosis of functional thyroid diseases. Comparison of results in a highly selected and a non-selected group of patients in relation to the blood PBI and T4I levels.

The value of measuring systolic time intervals for the diagnosis of functional thyroid disorders was studied. We were able to confirm that the systolic time intervals, namely the preejection period (PEP) are significantly shortened in hyperthyroidism and protracted in hypothyroidism. We were able to prove the rectilinear correlation between the PEP interval and Ig PBI in both highly selected and unselected groups of untreated patients with thyroid disorders. We were able to show much lower diagnostic value of other systolic intervals (as Q-S2) and indices (Weissler's index) compared to PEP. We are able to enumerate some pathological cardiovascular states, where the PEP interval is considerably influenced. With due respect to above-mentioned problems, we are convinced that the PEP measurement is of real diagnostic value in the bed-side diagnosis of thyroid disorders, moreover we believe it might help to solve some theoretical problems.

Electrocardiography↗
PubMed1979

[Action of grisin on the variability of an Acinomyces griseus culture and the use of the same antibiotic as a selection agent in the selection of active variants].

The effect of grisin on survival and variation of Actinomyces griseus producin grisin was studied. The efficiency of various concentrations of grisin on induction of variation according to the feature of the antibiotic production was compared. A possibility of increasing the productivity of strain. VNIIGenetics-115 by the use of the mutations of resistance to grisin is shown.

Anti-Bacterial Agents↗
PubMed1977

Ionic selectivity, saturation and block in gramicidin A channels: I. Theory for the electrical properties of ion selective channels having two pairs of binding sites and multiple conductance states.

A model for the gramicidin A channel is proposed which extends existing models by adding a specific cationic binding site at each entrance to the channel. The binding of ions to these outer channel sites is assumed to shift the energy levels of the inner sites and barriers and thereby alter the channel conductance. The resulting properties are analyzed theoretically for the simplest case of two inner sites and a single energy barrier. This for-site model (two outer and two inner) predicts that the membrane potential at zero current (Uo) should be a Goldman-Hodgkin-Katz equation with concentration-dependent permeability ratios. The coefficients of the concentration-dependent terms are shown to be related to the peak energy shifts of the barrier and to the binding constants of the outer sites. The thory also predicts the channel conductance in symmetrical solutions to exhibit three limiting behaviors, from which the properties of the outer and inner sites can be characterized. In two-cation symmetrical mixtures the conductance as a function of mole fraction is shown to have a minimum, and the related phenomenon of inhibition and block exerted by one ion on the other is explained explicitly by the theory. These various phenomena, having ion interactions in a multiply occupied channel as a common physical basis, are all related (by the theory) through a set of measurable parameters describing the properties of the system.

Electric Conductivity↗
PubMed1978

Effect of selective and non-selective beta-adrenoreceptor blockade on calf blood flow in hypertensive patients.

1. Dose-response curves of isoprenaline were constructed in nine hypertensive patients before and after either propranolol or metoprolol. 2. The decrease of diastolic blood pressure and increase of heart rate with isoprenaline were significantly more inhibited by propranolol than by metoprolol. 3. The increase in calf blood flow with isoprenaline was significantly more depressed after propranolol than after metoprolol. 4. The results suggest that the response of the vessels in the limbs to sympathetic stimulation is much less affected after metoprolol than after propranolol.

Blood Pressure↗