Seasonal changes of ionic concentrations in the vacuolar sap of Chara vulgaris L. growing in a brackish water lake.

The composition of the vacuolar sap of Chara vulgaris growing in a brackish water lake was estimated weekly over 2 years (1984-1985). The ionic concentrations of the main cations Na+, K+, Ca2+, and Mg2+ and the anion Cl- varied depending on cell age, developmental state, and season. The average of all measurements (in mM) was Na+: 35, K+: 106, Ca2+: 7, Mg2+: 23, Cl-: 101, SO 2-4 : 20, and PO 3-4 : 5. At the onset of growth in May/June the ionic content was lower compared to the mean value for the year, steadily increasing until it reached its maximum above the annual mean in winter. During the period of fructification (sexual reproduction: formation of antheridia and oogonia), when up to 100 mM sucrose was accumulated in the vacuolar sap, ionic content was lowest. This resulted in a fairly constant osmotic potential throughout the year. Mg2+ and Ca2+ concentrations were correlated with the physiological age of the cells.

Agentes etiológicos de uretritis infecciosa masculina en pacientes que concurren a laboratorios de Asunción / Etiological aspects o male infectious urethritis in patients attending laboratories of Asuncion

Esta investigación se efectuó para ampliar el conocimiento sobre los agentes etiológicos de la uretritis masculina en Asunción; se basó en una revisión retrospectiva de las fichas clínicas de 619 pacientes que acudieron con propósitos diagnósticos a tres laboratorios privados y a un laboratorio público de Asunción. La edad promedio ± DE fue de37,6±15,2 años (rango 0-91 años), 373 pacientes concurrieron a Meyer Lab, 166 al laboratorio San Roque, 68 al laboratorio de Santa Clara y 12 al laboratorio de Microbiología del IICS. En total se procesaron muestras de orina de 289 pacientes, secreción uretral de 326 y en 4 pacientes tanto orina como secreción uretral. Las indicaciones médicas fueron búsqueda de Neisseria gonorrhoeae en 295 pacientes, Chlamydia trachomatis en 256, Ureaplasma urealyticum en 264, Mycoplasma hominis en199. Se demostró la presencia de N. gonorrhoeae en el 6,4% de los casos, C. trachomatisen el 3,5%, U. urealyticum 11,5% y M. hominis 2,5%. A pesar de que se halló un franco predominio de la forma no gonocóccica, considerando las limitaciones que tiene el estudio por su carácter retrospectivo, es necesario realizar estudios prospectivos con mayor número de muestras para establecer con certeza la prevalencia de los agentes etiológicosde las uretritis infecciosas en el varón, incluyendo búsqueda de otros agentes infecciosos. Es necesario disponer de datos sobre uretritis en otros grupos socio económicos e investigar aspectos como la frecuencia en nuestro medio del síndrome de uretritis postgonocóccica (UPG) y de cepas de N. gonorrhoeae productoras de β lactamasa.

This study was carried out in order to contribute to the knowledge of the etiological agents of male urethritis in Asunción. It is based on a retrospective review of clinical records of 619 patients from one public and three private laboratories in Asunción. Theage mean ± SD was 37.6 ± 15.2 years (range 0-91 years); 373 patients were from Meyer Lab, 166 from San Roque Laboratory, 68 from Santa Clara Laboratory and twelve from the Laboratory of Microbiology of the IICS. Urine samples from 289 patients, urethra secretion from 326 and both types of samples from 4 patients were studied. Diagnosis of Neisseria gonorrhoeae was requested for 295 patients, Chlamydia trachomatis for 256,Ureaplasma urealyticum for 264, Mycoplasma hominis for 199. Presence of N. gonorrhoeae was demonstrated in 6.4% of the cases, C. trachomatis in 3.5%, U. urealyticum in 11.5% and M. hominis in 2.5%. Even though there was a clear predominance of non-gonococcal urethritis, considering the limitation of this study due to its retrospective nature, prospective studies with larger samples are necessary toestablish with certainty the prevalence of the etiological agents of male infectious urethritis, including the search of other infectious agents. It is also necessary to have data about urethritis in other socioeconomic groups and investigate aspects such as thefrequency of post-gonococcal urethritis syndrome (PGU) and beta-lactamase producing N. Gonorrhoeae strains in our area.

[Ticlopidine-induced cholestasis]. / Ticlopidin-induzierte Cholestase.

UNLABELLED: We report a case of ticlopidine-induced cholestatic hepatitis. CASE SUMMARY: An 82-year-old man suffered a myocardial infarction in February 1998. Because of persistent angina pectoris a coronary stent was implanted in May 1998. At this time medication with 1 x 250 mg ticlopidine was started in addition to the preexistent medication of aspirin 1 x 100 per day, metoprolol fumarate 1 x 95 mg per day and isosorbide dinitrate 1 x 100 mg per day. Three weeks after starting ticlopidine the patient complained of itching, and on day 28 painless jaundice developed. At this time, the serum activities of alkaline phosphatase (923 U/l), gamma-GT (823 U/l) and total bilirubin concentration (129 mumol/l) were markedly elevated, whereas the activities of the transaminases (AST 131 U/l, ALT 194 U/l) were slightly increased. An extra- or intrahepatic biliary obstruction was ruled out, and there were no signs of a toxic, infectious or immunological cause for the hepatic injury. Liver biopsy showed centro-acinar cholestasis. After drug discontinuation the itching stopped after 4 weeks and jaundice disappeared after 2 weeks. Eight months after the onset of symptoms, the activities of alkaline phosphatase (226 U/l) and gamma-GT (213 U/l) were still elevated but the patient was asymptomatic. CONCLUSIONS: Ticlopidine-induced mild serum liver enzyme elevations have been observed in some studies (incidence 1-2%). The incidence of severe hepatitis has been estimated at 0.0013%. Only a few cases (in approximately 20 patients receiving ticlopidine) of a severe cholestatic pattern of injury have been reported. In all cases the jaundice resolved and serum liver enzyme concentrations normalised over a period of months. Characteristically, liver biopsies demonstrated centro-acinar cholestasis. Monitoring of serum liver enzyme concentrations is not recommended. When itching or jaundice occur in a patient taking ticlopidine, the possibility of toxic liver damage should be taken into account.

The use of antibodies to the polypyrimidine tract binding protein (PTB) to analyze the protein components that assemble on alternatively spliced pre-mRNAs that use distant branch points.

We are using the rat beta-tropomyosin (beta-TM) gene as a model system to study the mechanism of alternative splicing. Previous studies demonstrated that the use of the muscle-specific exon is associated with the use of distant branch points located 147-153 nt upstream of the 3' splice site. In addition, at least one protein, the polypyrimidine tract binding protein (PTB), specifically interacts with critical cis-acting sequences upstream of exon 7 that are involved in blocking the use of this alternative exon in nonmuscle cells. In order to further study the role of PTB, monoclonal antibodies to PTB were prepared. Anti-PTB antibodies did not inhibit the binding of PTB to RNA because they were able to supershift RNA-PTB complexes. To determine if additional proteins interact with sequences within the pre-mRNA, 35S-met-labeled nuclear extracts from HeLa cells were mixed with RNAs and the RNA-protein complexes were recovered by immunoprecipitation using antibodies to PTB. When RNAs containing intron 6 were added to an 35S-met-labeled nuclear extract, precipitation with PTB antibodies showed a novel set of proteins. By contrast, addition of RNAs containing introns 5 or 7 gave the same results as no RNA, indicating that these RNAs are unable to form stable complexes with PTB. These results are in agreement with our previous studies demonstrating that PTB interacts with sequences within intron 6, but not with sequences within introns 5 and 7. When 35S-met-labeled HeLa nuclear extracts were mixed with biotinylated RNA containing intron 6 and the RNA-protein complexes were recovered using streptavidin-agarose beads, an identical pattern of proteins was observed when compared with the immunoprecipitation assay. Analysis of the proteins that assembled on introns 5, 6, or 7 using biotinylated RNA revealed a unique set of proteins that interact with each of these sequences. The composition of proteins interacting with sequences associated with the use of the 3' splice site of intron 6 included proteins of 30, 40, 55, 60, 65, 70, 80, and 100 kDa. Microsequencing identified two of the proteins to be Sam68 and the Far Upstream Element Binding Protein (FBP) from the c-myc gene. In addition, a comparison of the proteins that assemble on introns from the alpha- and beta-TM genes that utilize distant branch points revealed common as well as unique proteins that assemble on these introns. These studies identify a set of proteins, in addition to PTB, that are likely involved in the use of distant branch sites associated with the use of alternatively spliced introns.