Biomedical subjects
J Cervenka
Publications and source records attributed to J Cervenka.
[Health and the environment].
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Taurodontism: an anomaly of teeth reflecting disruptive developmental homeostasis.
Two models concerning morphometric traits occurring frequently in aneuploidy states posit, respectively, 1) that they reflect the expression of specific major oligogenes for that trait on the chromosome involved or 2) that they result from a generalized disruption of developmental homeostasis. In contrast to previous studies that have investigated variations in morphometric traits in a single aneuploidy state, this study investigates a single morphometric trait, taurodontism, as it occurs in otherwise normal individuals, in nonchromosomal syndromes, and in aneuploidy syndromes to determine whether the trait best fits the oligogene or the disrupted developmental homeostasis model. Taurodontism is diagnosed from dental radiographs. It is an extreme variation in tooth form seen in multirooted teeth in which the bifurcation or trifurcation of the roots is displaced toward the apex of the root, resulting in increased size of the pulp chamber. The point of furcation, and consequently the size of the pulp chamber, is a quasicontinuously distributed trait. The results indicate that taurodontism most likely is the result of disrupted developmental homeostasis.
Effects of fosenopril, a once-daily angiotensin-converting enzyme inhibitor, on resting and exercise-induced changes of blood pressure, hormonal variables, and plasma potassium in essential hypertension.
Fosenopril, a new angiotensin-converting enzyme (ACE) inhibitor, is a prodrug that is converted to its active diacid metabolite after intestinal absorption. Its excretion is equally divided between hepatic and renal routes. This study details the efficacy of fosenopril at rest and during exercise on blood pressure, plasma potassium, plasma renin activity, and plasma aldosterone in 11 hypertensive males, mean age 55 years. Individual subjects underwent an identical exercise protocol (bicycle ergometry) on placebo and on active treatment. Supine mean blood pressure fell from 116 to 100 mm Hg, P less than 0.005, and at 9 minutes of exercise mean blood pressure fell from 137 to 125 mm Hg, P less than 0.01 on fosenopril. Plasma potassium fell slightly at rest from 4.27 to 3.96 mmol/L and during exercise from 5.23 to 4.93 mmol/L, both P less than 0.025. Plasma renin activity (ng/mL/hr) rose on fosenopril, at rest 0.94 to 4.72, and during exercise 2.06 to 10.39, both P less than 0.005. Aldosterone changes on treatment were marginal and nonsignificant. The compound was well tolerated and free of subjective and routine laboratory side effects. Its antihypertensive action is broadly similar to the other ACE inhibitors currently available.
Enteroviruses and coliphages in different water ecosystems.
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[Analysis of foci of viral hepatitis B in selected areas. Preliminary report].
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[Carbocysteine--an effective mucolytic in cystic fibrosis of the lungs].
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[The first retard theophylline made in Czechoslovakia for the treatment of asthma in children--Spophyllin Spofa].
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Premature chromosome condensation induced by electrofusion.
Premature chromosome condensation of G1, G2, and S-phase chromosomes has been achieved by the use of electrofusion in the fusion of Chinese hamster ovary (CHO) cells and HeLa cells and CHO cells with human leukocytes. Very high yields of heterokaryons, of over 80%, as well as elimination of adverse effects of chemical and viral fusion agents, facilitated induction of premature chromosome condensation of high quality.
Coxsackie virus infection in association with heart affection in man.
The frequency of actual infections by selected types of coxsackie virus (B1-B6, A7, A9) has been followed up in adult patients hospitalized for reason of heart disease. Criteria of actual coxsackie virus infection have been defined, including a significant rise of titer of virus neutralizing antibodies and/or presence of virus-specific IgM antibodies. An actual coxsackie virus infection has been found in 71 (46.3%) out of 153 patients. Most frequently coxsackie B1 virus infection (24 times) and B4 (17 times) could be proved. In sera of patients with actual coxsackie virus infection, a higher proportion of infection with some types of coxsackie viruses, along with the presence of antibodies against a larger number of coxsackie virus types has been found, as compared to sera from patients without actual coxsackie virus infection, and/or, in sera of healthy blood donors (control group). The role of repeated infections with different types of coxsackie virus in the etiology of heart disease has been discussed.
[The incidence of viral hepatitis in Slovakia 1981-1985].
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Serum zinc is unaffected by effective captopril treatment of hypertension.
Captopril, a sulfhydryl compound that lowers blood pressure by inhibiting the zinc metalloenzyme, angiotensin converting enzyme, may occasionally result in ageusia, a symptom also associated with zinc deficiency. We therefore studied serum zinc and copper concentrations in a group of 14 essential hypertensive subjects before treatment and after 5-6 months of antihypertensive oral monotherapy with either captopril (50 mg, twice daily; n = 7) or other drugs (propranolol or alphamethyldopa; n = 7). Serum zinc and copper were unaltered by either regimen. Thus, zinc depletion is an unlikely consequence of long-term exposure to captopril, at least in the dosages commonly used for treatment of hypertension.
Prevalence of nosocomial infections in selected hospitals.
A point prevalence survey of NI in 10 hospitals has been carried out with the aim to obtain more valid results about their occurrence and to raise the interest of clinicians in this problem. Altogether data on 5,553 hospitalized patients have been evaluated. An epidemiologist along with a clinician jointly found a total 365 of NI in 344 patients a point prevalence 6.6%. The prevalence ranged between 3.6 and 10.5% for different hospitals. The highest NI prevalence was found in surgical wards (urology 19.6%, surgery 12.2%). Undesirably high prevalence of NI was observed in paediatrics (mainly diarrhoeal diseases) and neonatal (conjunctivitis) wards. Infections of the upper respiratory tract were most frequently followed by surgical wound infections and infections of the urinary tract. The occurrence of NI of surgical wounds, urinary tract infections and infections of skin was increasing, while the occurrence of infections of gastrointestinal tract and of the eye was decreasing with age. Gram-negative bacteria were more frequently isolated than Gram-positive bacteria (2:1).
Patterns of BrdU incorporation in homogeneously staining regions and double minutes.
The replication chronology of two structural chromosome abnormalities linked to the amplification phenomenon of DNA sequences was investigated. Three cell lines containing homogeneously staining region (HSR) chromosomes (IMR-32, MK42, and COLO-320) and one line with double minutes (DM) (SW-613) were examined. Using a bromodeoxyuridine-Hoechst 33258-Giemsa method, the HSR in the three cell lines were shown to be composed of subunits that replicated their DNA throughout all portions of the S-phase of the cell cycle. The double minute chromosomes were observed to replicate randomly throughout the entire S-phase, with no pattern evident. These results are consistent with the suggestion that DNA from HSR and DM are structurally and functionally related. Moreover, this observation that these amplified regions replicate their DNA throughout the entire S-phase favors the idea that, during amplification processes, both early and late replicating sequences are included. The apparent discordance between staining characteristics and replication behavior exhibited by some HSR and DM are also discussed.
Appearance of the rat testicular receptor for calcitriol (1,25-dihydroxyvitamin D3) during development.
In the present study we have examined the developmental changes in the concentration of receptors for calcitriol in high-salt cytosol from the rat testis. Receptors for calcitriol were undetectable (less than 0.4 fmol/mg protein) until day 24, after which there was a rapid increase to reach adult levels (6-8 fmol/mg protein) between day 50-60. The lack of receptors in high-salt cytosol from the immature rat testis is not due to degrading enzymes, since cytosols prepared from the combination of equal volumes of testis homogenates from immature and adult rats had binding levels exactly half of that found in "adult controls". Furthermore, the increase in specific binding of [3H]calcitriol during development is due to an increase in the number of receptor sites, and is not due to a change in the apparent affinity of the receptors (Kd approximately equal to 1 X 10(-11) M at 0 degrees C). These results may explain why we previously were unable to demonstrate calcitriol receptors in cultured Sertoli cells and peritubular cells isolated from 19-day old rats. Furthermore, they indicate that calcitriol may be of minor importance for testicular function in the immature rat. The role of calcitriol in the pubertal and adult testis remains to be established.
Effects of adenosine analogs on glucagon-stimulated adenosine 3',5'-monophosphate formation in Sertoli cell cultures from immature rats.
In the present study, we have examined the effects of two adenosine analogs, (-)N6-(R)phenyl-isopropyl-adenosine (PIA) and 2-chloro-adenosine, on glucagon- and FSH-stimulated cAMP production in Sertoli cell cultures isolated from immature (19-day-old) rats. Both FSH and glucagon caused a 5- to 10-fold stimulation of cAMP levels in the spent media from Sertoli cell cultures during an 18-h incubation. Addition of 1 microM PIA significantly inhibited both FSH- and glucagon-stimulated cAMP levels. In the presence of a maximal concentration of glucagon (2.5 micrograms/ml), PIA caused a concentration-dependent inhibition of cAMP formation, and the concentration of PIA causing half-maximal inhibition of cAMP formation (IC50) ranged from 0.5-1 nM. When Sertoli cells were incubated with increasing concentrations of glucagon (1.28 ng/ml to 4.00 micrograms/ml) in the absence and presence of either PIA (1.0 microM) or 2-chloro-adenosine (10.0 microM), the responses to glucagon, measured as cAMP formation, were almost completely abolished. 1-Methyl-3-isobutylxanthine (MIX), a well known inhibitor of cAMP phosphodiesterase activity, is also an inhibitor of adenosine binding to receptors on the cell membrane. When Sertoli cells stimulated with glucagon (2.5 micrograms/ml) were incubated in the absence and presence of MIX (0.1 mM) and increasing concentrations of PIA (0.025-10,000 nM), the presence of MIX reduced the inhibitory activity of PIA by almost 2 orders of magnitude (IC50 without MIX, 0.5 nM; IC50 with MIX, 20 nM). Thus, the present study shows that adenosine analogs inhibit agonist-stimulated cAMP formation in cultured Sertoli cells, and that MIX reduces this effect. This indicates that cultured Sertoli cells from immature rats contain A1-receptors for adenosine mediating inhibitory effects on adenylate cyclase.
[Prevalence of nosocomial infections in a type II hospital].
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Gonadal tumors in patients with gonadal dysgenesis and sex chromosomal rings and fragments.
Patients with female phenotypes and dysgenetic gonads harboring testicular tissue have a markedly increased risk of developing gonadal tumors. Cytogenetic demonstration of Y chromatin is the currently accepted criterion for performing prophylactic gonadectomies in these women. We studied four patients with dysgenetic gonads containing either testicular tissue or germ cell tumors. All had small sex chromosomal fragments which could not be characterized by conventional cytogenetic studies. Clinical features, DNA replication studies, and immunologic assays of Xga and H-Y antigens failed to correlate consistently with the gonadal histology. We recommend prophylactic gonadectomies and subsequent hormone replacement in all patients with female phenotypes, gonadal dysgenesis, and cytogenetically indeterminate sex chromosomal fragments.