[A rare case of congenital dentin dysplasia in a child aged 8 years]

In the reported case the authors observed a considerable mobility of all milk teeth and permanent teeth. The degree of this mobility varied. The crowns of milk and permanent teeth had a normal size, shape and colour. All teeth were unresponsive to thermal and electric stimulation. Radiological examination showed a nearly complete lack of roots and complete absence of pulp chambers and root canals. This was confirmed by histological examinations demonstrating that the inner part of the teeth in the crown and root was filled with hard masses which in light microscopy resembled newly forming compact bone with Haversian structures. The absence of resorption sinuses in the rudimentary roots was noted. Paediatric examination failed to demonstrate any abnormalities.

Interaction of signal transduction pathways in mediating acid secretion by rat parietal cells

To examine the role of protein kinase C (PKC) on the acid secretory activity of isolated rat parietal cells, histamine-and dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP)-stimulated [14C]aminopyrine accumulation was determined in the presence of agents that redistribute PKC activity to plasma membranes. Phorbol 12-myristate 13-acetate (PMA), 1-oleoyl-2-acetylglycerol (OAG), and phospholipase C inhibited, in a dose-dependent fashion, histamine- and DBcAMP-stimulated [14C]aminopyrine accumulation. Because PKC inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) reversed the effect, the results suggest that inhibition of histamine- or DBcAMP-stimulated [14C]aminopyrine accumulation induced by PMA, OAG, or phospholipase C was caused by increased activity of PKC in plasma membrane. To determine where in the cascade of events PKC inhibits acid secretion, histamine-, cholera toxin-, and forskolin-stimulated [14C]aminopyrine accumulation was measured with or without PMA. Because the percent of inhibition by PMA of [14C]aminopyrine accumulation was similar with the three secretagogues, the results suggest that PKC inhibits acid secretion at a point beyond adenosine 3',5'-cyclic monophosphate (cAMP) production. This was supported by the fact that PMA had no effect on histamine-stimulated production of cAMP and by the finding that activation of PKC had the same effect on histamine- or DBcAMP-stimulated [14C]aminopyrine accumulation. Histamine and DBcAMP inhibited PKC activity, suggesting a reciprocal interaction between PKC and histamine-triggered signal transduction pathway.

Local anesthetics (benzyl alcohol, lidocaine, procainamide) inhibit aminopyrine accumulation in isolated rat parietal cells

The present studies were designed to examine the effect of local anesthetics (benzyl alcohol, lidocaine, and procainamide) on the secretory response of parietal cells to histamine, dbcAMP, and carbachol. Studies were performed in vitro using isolated cells from rat stomachs, and acid production was determined by 14C-aminopyrine accumulation. In addition, the (H(+)-K+)-ATPase activity of microsomal vesicles isolated from parietal cells was determined. Lower concentrations of the drugs studied increased the basal aminopyrine accumulation and potentiated the secretory response of parietal cells to histamine and dbcAMP. At higher concentrations local anesthetics progressively inhibited both the basal 14C-aminopyrine accumulation and that stimulated by histamine, dbcAMP or carbachol. While a low concentration of local anesthetics increased gastric microsomal (H(+)-K+)-ATPase activity, higher concentrations inhibited enzyme activity to about 80% of those activities found in resting parietal cells. We conclude that increased aminopyrine accumulation may reflect the activation of membrane-bound enzyme(s) involved in the cAMP-dependent signal transduction pathway mediating acid secretion by parietal cells. In turn, it is possible that the inhibition of aminopyrine accumulation by local anesthetics at higher concentrations can relate to two different mechanisms: (1) the nonspecific effect of local anesthetics that causes simple proton neutralization (as weak bases), and (2) to a minor extent their inhibitory effect on proton pump activity.

Molecular characterization of the cysJIH promoters of Salmonella typhimurium and Escherichia coli: regulation by cysB protein and N-acetyl-L-serine

The cysJIH promoter regions from Salmonella typhimurium LT7 and Escherichia coli B were cloned and sequenced. Primer extension analyses showed that the major in vivo transcription initiation site in S. typhimurium is located 171 nucleotides upstream of the cysJ start codon. Minor start sites were found 8 and 9 nucleotides downstream of the major site. In vivo transcription initiation in E. coli was found to occur at a single site 66 nucleotides upstream of the cysJ start codon. Primer extension studies also indicated that chromosomal cysJIH transcription is stimulated by sulfur limitation and repressed by growth on L-cystine. Paradoxically, in strains carrying plasmids containing the S. typhimurium cysJIH region, the highest levels of primer extension products were found with RNA from cells grown on L-cystine, even though levels of the proteins encoded by cysJ and cysI were normally repressed. In vitro transcription runoff studies with DNA template from the S. typhimurium cysJIH promoter region showed synthesis of a product originating at the major in vivo start site, which was dependent on the presence of purified cysB protein and either O-acetyl-L-serine or N-acetyl-L-serine. N-Acetyl-L-serine was 10- to 30-fold more active than O-acetyl-L-serine as an in vitro inducer of cysJIH transcription.

Interferon-gamma and interleukin-1 alpha induce transient translocation of protein kinase C activity to membranes in a B lymphoid cell line. Evidence for a protein kinase C-independent pathway in lymphokine-induced cytoplasmic alkalinization

We have previously shown that recombinant murine interferon-gamma, rIFN-gamma, and recombinant human interleukin-1 alpha, rIL-1 alpha, induce differentiation of murine pre-B-like cell line 70Z/3, a finding associated with stimulation of Na+/H+ exchange across the plasma membrane. The present study was designed to test whether the enhanced Na+/H+ exchange is mediated by Ca2+/phospholipid-dependent protein kinase C. The results show that two structurally different peptides, rIFN-gamma and rIL-1 alpha, induce identical patterns of transient translocation of protein kinase C from the cytosol to the membranes. The increase in membrane-associated protein kinase C activity was first detected 20 min after exposure to the lymphokines. This activity peaked at 30 min and was back to baseline by 2 h. At each time point, the increase in membrane-associated protein kinase C activity corresponded to a decrease in the activity of protein kinase C in the cytoplasmic fraction. The total cellular activity (cytosol + membrane) remained the same. Two series of experiments were carried out to test the role of protein kinase C in mediating the lymphokine-stimulated Na+/H+ exchange. In the first, the effects of rIFN-gamma and rIL-1 alpha on cytoplasmic pH were measured in the presence of a protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine, H-7. In the second, rIFN-gamma- and rIL-1 alpha-induced cytoplasmic alkalinization was determined in cells containing decreased protein kinase C activity. Under both experimental conditions, lymphokine-induced cytoplasmic alkalinization was not attenuated. These results indicate that, although both rIFN-gamma and rIL-1 alpha cause association of protein kinase C with membranes, activation of protein kinase C is not required for rIFN-gamma or rIL-1 alpha to stimulate Na+/H+ exchange across the plasma membrane.

[Mandible magnitude in Crouzon syndrome]

The authors describe Crouzon syndrome in 5 patients aged 9, 10, 13, 40 and 43 years. Typical image of Crouzon syndrome has been found in the woman and three children and its abortive form--in the man. The authors present their own studies on branch height, length of the body of the mandible and the angle value of the mandible according to the Costaras-Volarich and Pruzancky method in their paper. The ratio of the branch to the body is 1:1 in all patients under examination and it is not equal to the normal ratio of 2:3. The angle of the mandible is also greater than the normal value. The authors put forward a hypothesis that pseudomesioclusion in the sick with Crouzon syndrome can be conditioned not only by maxilla dysplasia but also by excessive height of the branch and increased angle value of the mandible basing on their own observations. This hypothesis, however, exact further radiocephalometric studies and close cooperation of obstetricians, paediatricians and orthodontists.

DNA sequences of the cysB regions of Salmonella typhimurium and Escherichia coli

Nucleotide sequences of the cysB region of Salmonella typhimurium and Escherichia coli have been determined and compared. A total of 1759 nucleotides were sequenced in S. typhimurium and 1840 in E. coli. Both contain a 972-nucleotide open reading frame identified as the coding region for the cysB regulatory protein on the basis of sequence homology and by comparison of the deduced amino acid sequences with known physicochemical properties of this protein. The DNA sequence identity for the cysB coding region in the two species is 80.5%. The deduced amino acid sequences are 95% identical. The predicted cysB polypeptide molecular weights are 36,013 for S. typhimurium and 36,150 for E. coli. For both proteins a helix-turn-helix region similar to that found in other DNA-binding proteins is predicted from the deduced amino acid sequence. Sequences upstream to cysB contain open reading frames which represent the carboxyl-terminal end of the topA gene product, DNA topoisomerase I. A pattern of highly conserved nucleotide sequences in the 151 nucleotides immediately preceding the cysB initiator codon in both species suggests that this region may contain multiple signals for the regulation of cysB expression.

Erythrocyte porphobilinogen deaminase activity in liver disease

The activities of erythrocyte porphobilinogen deaminase were studied in patients with various liver diseases and in control groups. The lowest enzyme activities were found in patients with acute intermittent porphyria, and the highest ones in those with increased hemopoietic activity. Patients with liver cirrhosis or chronic active hepatitis had porphobilinogen deaminase activities that were significantly higher than in normal subjects and did not depend on disease activity. In patients with acute hepatitis, porphobilinogen deaminase activities varied depending on the phase of disease, being normal at onset and after 3-4 mo, and elevated to the values observed in chronic liver disease between 2 and 4 wk of hospitalization. The differences in porphobilinogen deaminase activities between patients with liver disease and controls did not relate to red cell age as determined by density gradient centrifugation. Therefore, although the mechanism responsible for the increase in porphobilinogen deaminase activities in liver disease is not clear, the results of this study suggest that it is independent of the presence of immature red cells in the circulation.

Serum retinol level in patients with colorectal premalignant and malignant lesions

Serum retinol levels were determined by a fluorometric method in patients with colorectal cancer or polyps and those with inflammatory bowel disease. Serum retinol levels in patients with benign or malignant colorectal polyps and stage B cancer (modified Dukes' classification) were similar to those found in controls. By contrast, serum retinol levels were significantly lower in patients with Dukes' stage C or D. Among cancer patients that were followed after surgical treatment serum retinol levels did not differ significantly from those found in controls. Patients who died of metastases during follow-up possessed very low serum retinol levels. These findings suggest that a decreased serum retinol level in cancer patients is a consequence rather than a precursor of the neoplastic process. Furthermore, this study suggests that the marked decrease in serum retinol level might be an indicator of poor prognosis in colorectal cancer patients after surgery.

Liver function and pharmacokinetics of molsidomine and its metabolite 3-morpholinosydnonimine in healthy volunteers

Plasma levels of N-carboxy-3-morpholinosydnonimine ethyl ester (molsidomine, Corvaton) and its pharmacologically active metabolite 3-morpholinosydnonimine (SIN-1) were measured in six healthy male and female volunteers after single intravenous and oral dosing of 4 mg molsidomine. Additionally indocyanine green and phenazone (antipyrine) clearances were determined to estimate hepatic blood flow and metabolic liver function in each subject. The pharmacokinetic parameters of molsidomine were similar to already published data in healthy volunteers and patients. The plasma level of SIN-1 formed was always lower than the molsidomine level but obviously reflects the corresponding molsidomine concentration time course in plasma. Indocyanine green plasma clearance was reduced by 15%. after intravenous dosing of 4 mg molsidomine. There was no clear-cut relationship between the plasma clearances of molsidomine and phenazone in these subjects with normal metabolic liver function.

Pharmacokinetics of molsidomine in humans

The pharmacokinetics of molsidomine were investigated in the plasma and urine of healthy male volunteers and patients with coronary heart disease after intravenous and/or oral administration of different galenic dosage forms of molsidomine. Following the rapid attainment of mean peak concentration (15 +/- 7 mg/ml) 0.5 to 1.0 hour after single oral dosing of 2 mg of molsidomine, the plasma levels of the unchanged drug decline monoexponentially with a mean half-life of 1.6 +/- 0.8 hours. Molsidomine is absorbed almost completely. Its absolute bioavailability (44 +/- 15%) and a 14C-labeled triale give evidence of quick biotransformation of molsidomine to active metabolites. Less than 2% of the unchanged drug appear in the urine, but renal excretion is the main route of elimination of the metabolites in humans (90% to 95%). The kinetics parameters after administration of multiple dosages of 4 mg of molsidomine over 29 days do not account for accumulation of or enzyme induction by molsidomine. The finding of obvious good correlations between plasma levels of the predrug molsidomine and corresponding pharmacodynamic data can be made plausible by the time course of concentration values of the active metabolite SIN-1 in plasma.

Relationship between pharmacokinetics and pharmacodynamics of molsidomine and its metabolites in humans

The pharmacokinetic properties and hemodynamic effect of molsidomine and its pharmacologically active metabolite SIN-1 were investigated in 13 healthy volunteers following single oral doses. Hemodynamic changes were measured by finger plethysmography (peripheral arterial resistance), impedance plethysmography (venous distensibility), heart rate, and blood pressure. Plasma concentrations of molsidomine, SIN-1, and SIN-1C were measured by means of high-pressure liquid chromatography. Oral administration of rapidly dissolving tablets of molsidomine (2 tablets of 4 mg), a sustained-release form of molsidomine (8 mg), and SIN-1 (4 mg) caused an increase of the a/b ratio of the finger plethysmogram and an increase of the venous distensibility. Heart rate and blood pressure remained unaffected. The time course of the peripheral arterial effect mimicked the time course of plasma concentrations of molsidomine and SIN-1. Similar to the results in animals, molsidomine was metabolized in humans to SIN-1 and subsequently degraded to the inactive metabolite SIN-1C. The kinetic profile of both metabolites could be followed in the plasma. The rate-limiting step in the metabolic sequence of molsidomine was found to be enzymatic hydrolysis and decarboxylation of molsidomine to SIN-1. Concentration-response curves of the a/b ratio of the finger plethysmogram showed that the plasma concentrations required to produce a definite effect are much higher for molsidomine than for SIN-1. This shows that the pharmacodynamically active form of molsidomine in humans is the metabolite SIN-1. The changes in the finger plethysmogram produced by SIN-1 suggest that in addition to the effect on the venous site, SIN-1 also dilates the peripheral arterial site.

Mean time and first-pass metabolism

The theoretical principles are outlined for estimating the fraction of a drug undergoing first-pass metabolism using only the plasma levels found after a single oral dose. Data for 3 drugs are used to illustrate the method. It involves analysis of the parent drug and the metabolite formed during the first passage through the gut wall and liver and evaluation of their total mean times. The mean time characteristics of molsidomine, nortriptyline and propranolol are considered and they confirm the theoretically deduced dependency of the mean time of the parent drug and the metabolite. Whether the results are more precise than those obtained from comparison of areas after oral and intravenous administration is discussed. From the data presented it is clear that the mean time method depends on the scatter inherent in the data. In order to estimate the true first-pass effect, greater scatter requires an increased number of data pairs, i.e. subjects. If intravenous data are not available, however, the method described provides a rough but worthwhile estimate of the first pass effect.

Pharmacokinetics of an extended-release dosage form of molsidomine in patients with coronary heart disease

Molsidomine (N-carboxy-3-morpholino-sydnonimine-ethylester; Cassella-Riedel Pharma GmbH, Frankfurt/M. FRG) has an antianginal effect for up to 3-5 h after oral administration of 2 mg Corvaton [1]. Plasma levels of the parent drug can be measured during this interval. A new galenic formulation (Corvaton retard) has been developed to prolong the duration of the therapeutic action and to improve patient compliance. The present study was carried out to establish whether the in vitro dissolution profile of the tablet was reflected in vivo, thus permitting prediction of plasma molsidomine levels in patients with coronary heart disease.

Intravenous and oral administration of molsidomine, a pharmacodynamic and pharmacokinetic study

In 12 healthy male volunteers, molsidomine 1, 2 and 4 mg i.v. increased resting heart rate and decreased systolic blood pressure, the latter still being affected after 8 hours. After single oral doses of 1 and 2 mg, systolic pressure tended to be reduced for 90 minutes and exercise heart rate tended to be increased. After oral treatment with 2 mg molsidomine three times daily for 1 week, the pharmacokinetic parameters and the effects on heart rate and blood pressure after the final dose were not different from those after the first dose. The terminal half-life was independent of dose and route of administration. Clearance and distribution volume were not dose-dependent. The bioavailability of a 2 mg oral dose of molsidomine was 44%. Inter-individual variation in heart rate, blood pressure and pharmacokinetics was observed.

Urinary porphyrins in liver disease

By use of quantitative thin-layer chromatography, urinary porphyrins were examined in 40 healthy volunteers, 38 patients with prophyria cutanea tarda (PCT), and 139 patients with various liver diseases. Significant elevations not only of coproporphyrin but also of some other porphyrins were found in many patients with liver disease. However, there was no evident relationship between porphyrin disturbances and functional or clinical findings, and all of these non-PCT patients who initially demonstrated intense uroporphyrinuria, when re-studied apparently had more normal porphyrin excretion. It seems, therefore, that whereas porphyrin estimations are useful in porphyrias, no clinically important conclusions can be drawn from urinary findings in patients with liver disease. The origin of defective haem biosynthesis in liver disease remains obscure. It can only be speculated that transient and reversible urocoproporphyrinuria may occur in patients with defective hepatic uroporphyrinogen decarboxylase activity who clinically and biochemically are not porphyric.

Determination of pirlindole in plasma and urine by high-performance liquid chromatography

A high-performance liquid chromatographic method is described for the analysis of pirlindole [2,3,3a,4,5,6-hexahydro-8-methyl-1H-pyrazino(3,2,1-jk)carbazole hydrochloride], a new antidepressive drug. The drug was extracted from plasma into dichloromethane, and the analysis was carried out on a reversed-phase column, the effluent being monitored by fluorescence detection. The method is selective and sensitive (limit of detection 1-2 ng/ml plasma). Urine analysis was done by direct injection of the diluted sample. The method was applied to the analysis of plasma and urine samples of eight healthy male volunteers who received a 75-mg oral dose of a tablet formulation of pirlindole. The method was also applied to a study in three beagle dogs which received pirlindole (1 mg/kg) by infusion (0.1 mg/kg/min) and orally (10 mg/kg) to estimate the absolute bioavailability of the drug.

[Lipoprotein regulatory effect of molsodomine in rats]

The antianginal drug N-ethoxycarbonyl-3-morpholinosydnonimine (molsidomine, Corvation) was orally administered (dose range 10(-5) - 10 mg/kg) to Wistar rats over 7 d once a day. The concentration of low density lipoprotein (LDL)-cholesterol in serum was decreased (40-45%) by therapeutic relevant dosages of molsidomine corresponding to an increase (80%) of the vasoprotective index high density lipoprotein (HDL)/LDL. HDL-cholesterol stayed unchanged. Clofibrate did not change the concentration of the lipoproteins in rat serum under equimolar conditions.

Abnormalities in liver function and morphology and impaired aminopyrine metabolism in hereditary hepatic porphyrias

The aminopyrine breath test and measurement of postprandial serum bile acids were performed in 67 patients with well-documented hereditary hepatic porphyria. Elevated postprandial serum bile acids levels were found in 75% and the aminopyrine breath test was abnormal in 42% of the patients studied. These function tests exhibited a statistically significant correlation with the excretion of porphyrin precursors in patients with acute intermittent porphyria. Furthermore, all 12 patients with acute intermittent porphyria who had a liver biopsy because of abnormalities in the aminopyrine breath test or postprandial serum bile acids measurement, or both, were found to have diffuse, moderately severe, but nonspecific ultrastructural changes of hepatocytes, indicative of significant subcellular damage. While a direct relationship between functional and morphologic abnormalities is speculative, it is possible that the defective heme biosynthesis, perhaps related to the reduced aminopyrine demethylation, could form the basis for the ultrastructural hepatic changes in porphyria. This, in turn, could be the cause of the elevated postprandial serum bile acids levels.

Effect of DNA gyrase inhibitors on gene expression of the cysteine regulon

Nalidixic acid inhibits the expression of those cysteine genes which are regulated by the cysB product, it has no affect, however, on the constitutively-expressed cysE gene. The expression of cysteine genes in a strain carrying a mutation in the nalA locus is resistant to this drug. Novobiocin affects the expression of cysteine genes similarly to nalidixic acid. The effect of nalidixic acid on the expression of genes in a cysteine constitutive mutant was studied.

Hepatitis B surface antigen and albumin in human hepatocytes. An immunofluorescent and immunoelectron microscopic study

A close correlation between the presence of hepatitis B surface antigen and albumin in the cytoplasm of hepatocytes infected with hepatitis B virus was established by immunofluorescence and immunoelectron microscopy in 52 liver biopsy specimens of various forms of hepatitis and liver cirrhosis. Albumin deposits usually accompanied cytoplasmic content of hepatitis B surface antigen, but were less frequently observed together with hepatitis B antigen localized in or on the membranes. Ultrastructural observations demonstrated albumin on the tubular and spherical forms of hepatitis B surface antigen in the endoplasmic reticulum. The hepatocytes with the content of hepatitis B surface antigen and albumin showed the ability of binding with the fluorescein-labeled preparation of polymerized human serum albumin. The affinity of polymerized albumin to hepatitis B surface antigen was considerably increased after preincubuation of liver sections with 2-mercaptoethanol that removed most of the originally present albumin. This may be indicative for the role of disulfide bonds in the formation of hepatitis B surface antigen-albumin complexes. These results justify the hypothesis that albumin may be incorporated into the viral coat protein during its synthesis in the cytoplasm of infected hepatocytes.