Product of mobility and lifetime of charge carriers in CdTe determined from low-frequency current fluctuations.

The model, which clarifies the low-frequency fluctuations of the current flowing in CdTe sample, makes it possible to determine the product of the mobility and lifetime of the charges in mentioned semiconductor. This model, with general validity for semiconductors, is based on the interaction of shallow traps with the valence or conduction band. As a result of the action of these centers, current fluctuations appear, the mean amplitude of which increases linearly with the inverse value of the frequency. It was found that the slope of this dependence is proportional to the product of mobility µ and a constant which is common to all shallow traps and which is denoted by the symbol a. The lifetime of charges located on shallow traps varies according to the relationship τ = a/f and for fmin it acquires a maximum value of τmax, which agrees with the stationary lifetime. For the p-CdTe crystalline semiconductor the mobility-lifetime product µpτp = (6.6 ± 0.3) × 10-7 cm2V-1was obtained. Similar study of n-type CdTe showed µnτn = (7.5 ± 0.3) × 10-8 cm2V-1.

[Regression of hypertrophy of the left ventricle in patients with hypertension after 6-month treatment with Fludex]. / Regression der Hypertrophie des linken Ventrikels bei Patienten mit Hypertonie nach 6monatiger Behandlung mit Fludex.

Indapamide (Fludex) administered in daily doses of 2.5 mg resulted in optimal improvement of the blood pressure in patients with mild or moderate hypertension. During the period of 6 months treatment that was tolerated well by the patients, no influence of indapamide on the levels of glucose, cholesterol, triglycerides, and creatinine in blood was observed. A mild decrease of serum potassium in blood was clinically not relevant. Using echocardiography and electrocardiography a regression of the hypertrophy of the left ventricle of the heart was observed.

Toxicity of morphazinamide compared with pyrazinamide.

In a toxicological study on rats two derivatives of pyrazine: morphazinamide (MZA) and pyrazinamide (PZA) were compared with the objective to verify the possibility of using MZA as a substitute for the hepatotoxic PZA. The daily recorded weight and food intake of the rats were statistically significantly changed in the experimental groups with MZA as well as those with PZA, as compared with the control group and the group fed parallelly, already after the sixth dose of MZA and PZA 2.5 g per kg body weight, and similarly changed were also the various biochemical blood and liver tissue tests. Yet, certain differences were observed between the action of MZA and PZA. Some explanation was obtained from PZA blood and tissue concentrations, determined in the course of 24 hours following the administration of the sixth dose of both drugs. A repeated administration of MZA led to a PZA cumulation in the blood and organs of the rats. The study demonstrated that both drugs are hepatotoxic and, in high doses, also nephrotoxic. Moreover, MZA decreases the concentration of plasmatic iron and causes spleen atrophy. It will not be, therefore, a suitable substitute for the hepatotoxic PZA.

Pharmacokinetics of antituberculosis drugs after oral isolated and simultaneous administration in triple combination.

On the basis of a mathematical analysis of the time course of the drug distributed in the organism there were studied pharmacokinetics of antituberculosis drugs after an isolated oral administration of doses used in daily treatment of tuberculosis, in INH, RMP, EMB, PZA, ETA, CS and TZ, and after a simultaneous--single and repeated--administration of INH, RMP, EMB in a triple combination, after the usual daily doses and after increased intermittent doses administered twice weekly. At first there were determined, with the use of chemical methods, blood concentrations of the antituberculosis drugs studied and their excretion with urine in an unchanged form. The results were analyzed pharmacokinetically by means of a one- compartment model with absorption. By an iteration process, based on non-linear regression analysis, the following pharmacokinetic parameters were calculated: Vd, Ka, Ke, T0.5 abs, T0.5 el, Tmax, Cmax, Clp tot and AUC. Their comparison revealed the following facts: The microbiologically most effective antituberculosis drugs--INH and RMP--are comparable even from the point of view of pharmacokinetics on account of similar pharmacokinetic parameters; in comparison with them EMB has half the size of the AUC, characterizing the efficacy of the drug. In this parameter PTA exceeds more than twice ETA; CS and TZ have a low Ke as well as Clp tot and a high T0.5 el, which is indicative of an insufficient excretion of both drugs. Pharmacokinetic parameters of PZA confirm the possibility of using the dose of 25 mg/kg in the treatment of tuberculosis. A simultaneous administration of the triple drug combination under study influences pharmacokinetic parameters of all the three antituberculosis drugs--it significantly decreases Ka as well as Ke, increases T0.5 el, Tmax, Vd and in INH also Clp tot, but only after a repeated administration. An intermittent administration of the mentioned triple drug combination significantly increases the area under the curve AUC in all the three antituberculosis drugs. This explains the same efficacy of higher doses of antituberculosis drugs, administered twice weekly, in comparison with a daily administration of lower doses of the same combination. The pharmacokinetic process of orally administered antituberculosis drugs can be analyzed according to a one-compartment model of pharmacokinetics, although the kinetics of certain antituberculosis drugs probably proceed in the organism in a more complicated way.

Causes for rifampicin toxicity--experimental study.

A 12-day-experimental study of rifampicin (RMP) on male rats followed both the biochemical indices signalling disorder of metabolic equilibrium in the organism, and distribution of RMP in the tissues. The study showed the RMP concentration to be manifold higher in the liver than in the blood and other organs; in epididymal fat the concentration in one half of that in the blood. RMP adversely affects the energy metabolism, i.e. intake and resorption of nutrients, especially metabolically and calorically important lipids and sugars. RMP is harmful also for liver parenchyma.

[Peritoneal form of adiaspiromycosis (author's transl)]. / Peritoneale Form der Adiasporose.

A female patient, aged 30 years was subjected in 1977 to an appendectomy because of a perforated gangrenous appendix associated with purulent peritonitis. Postoperatively she developed an intractable constipation persisting for more than one year. Because of suspected intestinal stenosis an exploratory laparotomy was performed which failed to disclose the presence of stenosis. Histological studies of excised peritoneal specimens were suggestive of tuberculous peritonitis. Since cultivation failed to provide evidence of mycobacteria and the clinical symptoms were not characteristic of a tuberculous involvement of the peritoneum it was decided to carry out a re-evaluation of the original histological slides. This revealed that the patient was infected with adiaspores of the fungus Emmonsia crescens which were disseminated over the entire peritoneum from the perforated appendix. The difficulties associated with the diagnosis which are due to the striking morphologic similarity between the minute nodules in adiasporosis and those in productive miliary tuberculosis, as well as because of the acid-fast adiaspore capsules, are stressed. Since Emmonsia crescens is spread in some regions of Czechoslovakia it may be expected that humans will come into contact with its spores either by inhalation or by alimentary ingestion.

Factors influencing the effects of the initial phase of tuberculosis chemotherapy.

Two groups of patients suffering from extensive pulmonary tuberculosis treated with daily or twice-weekly regimens of isoniazid (INH) plus rifampicin (RMP) plus ethambutol (EMB) were formed by random selection. The effectiveness of treatment was expressed by the slope of regression line calculated for each patient in terms of quantitative time dependent decrease of mycobacteria isolated by culture per 1 ml of sputum. Chemically serum concentrations of drugs in five time intervals following simultaneous administration were established. It was shown that the rate of decrease of mycobacteria did not significantly vary in the compared groups. Negativity was reached in 48 day on the average. The mean regression line with double standard deviation allocated patients with rapid, normal or slow sputum conversion. Rapid convertors were the youngest, excreted largest amounts of mycobacteria before the start of treatment, and their x-ray showed predominantly changes of exudative character. Slow convertors excreted least amounts of mycobacteria. In the group of slow convetors with daily regimen was significantly higher number of rapid INH inactivators compared with groups of rapid and normal convertors. Analysis of multiple correlation and variance of the ratio of mycobacterial decrease rate and of the parameters of the biological availability of drugs as expressed by the area under the curve of drug serum levels reveal the rate of mycobacterial decrease to be dependent always on the drug out of the combination. In daily regimen the decrease rate was controlled by INH, in the intermittent regimen by RMP. The speed of negativization could therefore be increased in daily regimen by increased doses of INH, chiefly in rapid INH inactivators. The most important share of RMP in the mycobacterial decrease rate during intermittent administration can be judged from dependence of biological availability on the dose of RMP. Under the experimental circumstances of this study the pharmacological means for speeding up negativization were best utilized. Further shortening of time necessary for obtaining negativity would be practicable only when residual factors are involved presumably existing beyond the region of pathogen and drug relationship.

Miliary tuberculosis in a patient after renal transplantation.

A report is presented on the first case of miliary tuberculosis in a group of 84 kidney transplant recipients treated in the Institute of Clinical and Experimental Medicine, Prague, until March 1976. The specific process was verified by bacteriological investigations of the sputum and urine. Productive specific tuberculoid-type nodules with sporadically occurring acidoresistant rods were detected in a bioptic specimen of the transplanted kidney. Also discussed are therapeutical problems in progressive renal graft insufficiency and in simultaneous chronic hepatopathy.