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Biomedical subjects

P Helbling

Publications and source records attributed to P Helbling.

9 recordsLinked to original sources
PubMed2000

Surveillance of antituberculosis drug resistance in Switzerland 1995-1997: the central link.

The purpose of the present paper is to investigate the usefulness of routine notification of antituberculosis drug susceptibilities. In Switzerland, laboratories have to report susceptibilities to isoniazid, rifampicin, ethambutol, and pyrazinamide to the Federal Office of Public Health. All clinical and laboratory information on every single tuberculosis case is routinely linked. Proportions of drug resistance were calculated and logistic regression was applied to evaluate the role of potential risk factors. Eighty percent (1056) of all culture-positive tuberculosis cases reported between October 1995 and December 1997 were analysed. The strains of 66 (6.3%) patients had resistances to at least one drug. Risk factors identified were previous antituberculosis treatment (adjusted odds ratio 7.3, 95% confidence interval 3.9-13.6), male sex (1.4, 1.1-2.0), and age <65 yrs (1.5, 1.0-2.3). Fourteen cases (1.3%), 13 of them foreign-born, were resistant to at least isoniazid and rifampicin. Reporting of drug susceptibilities allows routine assessment of the proportion of drug resistant tuberculosis and populations at risk. This proportion was found to be small in Switzerland. Risk factors were previous treatment for tuberculosis, male sex, and age <65 yrs. Resistance to at least isoniazid and rifampicin was predominantly found in foreign-born patients.

Adult↗
PubMed1998

[National reference centers for surveillance of infectious diseases in Switzerland: results of a delphi study].

The national reference laboratories are one of the tools used by public health authorities to control infectious diseases. The Swiss Confederation supports 9 national reference centers (NC), each dealing with a limited number of infectious agents. The purpose of this study was to evaluate if this network meets present day needs, whether it has to be redefined, and how it can be improved. Using the Delphi technique, 34 experts in the field of infectious diseases were questioned to establish a concept for NC in Switzerland. The main result of this study is that official reference laboratories are considered necessary. However, depending on the type of infectious agent, the following types of laboratories should be used: national reference centers, specialized laboratories and laboratories abroad. The study also defined criteria for the designation of NC, their field of action (general objectives, tasks, duration of the mandate, infectious agent to be monitored), evaluation criteria, and the type of funding. Furthermore, possible improvements in the present system were identified and the establishment of good collaborations with reference centers abroad was proposed.

Communicable Diseases↗
PubMed1998

Localization of the mosquito insulin receptor homolog (MIR) in reproducing yellow fever mosquitoes (Aedes aegypti).

The female mosquito takes a blood meal to produce a batch of eggs. Initiation of egg maturation and growth of oocytes is governed by several endocrine factors. Peptide factors from the brain are involved in this process and some are also responsible for the induction of ecdysone secretion. The latter appears to be required to maintain a high rate of vitellogenin synthesis. By analogy with the known functions of insulin-like molecules (e.g. bombyxins) which in insects activate the secretion of ecdysteroids, we have postulated that there is an insulin receptor homolog responsible for activation of endysone secretion in the ovary. We have recently cloned the mosquito homolog (MIR) and are now investigating its spatial and temporal distribution. Here, we have localized the insulin receptor (MIR) both at the mRNA and protein level using in situ-hybridization and immunocytochemistry. The receptor is expressed before a blood meal mainly in the nurse cells of ovaries. After a meal, follicle and nurse cells contain mRNA coding for the receptor. The intensity of expression rises in the follicle cells until they degenerate during choriogenesis. Immunocytochemical localization confirms the in situ data: the protein is present before and after a meal. Both methods confirm our previous findings by Northern blot analysis, in which the ovary was found to be the main source of the receptor mRNA. The dynamics of receptor mRNA are related to the dynamics of ecdysone secretion and its action on physiological processes.

Journal Article↗
PubMed1997

[Border health examination].

The Swiss federal law on epidemics of 1970 requires that the federal government takes measures to prevent the importation of communicable diseases from abroad. Today, the only examination required is screening for tuberculosis with the aim of early detection and treatment. The examination is compulsory for asylum seekers and refugees as well as for migrant workers from countries other than the members of the EU and EFTA, the U.S.A., Canada, Australia, and New Zealand. In addition, routine vaccinations are offered to asylum seekers and refugees. The first measures for asylum seekers are taken at the border by the Swiss Red Cross on behalf of the Swiss Federal Office of Public Health. The follow-up is carried out in the cantons by medical institutions designated by the cantonal health authorities.

Communicable Disease Control↗
PubMed1996

Cloning and expression analysis of Aedes aegypti opsin: adaptation of an in situ hybridization protocol for mosquitoes.

Opsin is a G protein coupled photoreceptor that activates a signal transduction cascade in the ommatidia. Its primary and secondary structure is conserved both in insects and vertebrates as exemplified by the Drosophila opsins. Through serendiplious cloning of a PCR fragment, we have identified an opsin cDNA. The latter was used to clone full length cDNAs from a mosquito head library. The main purpose of cloning was to have a positive control probe to establish an in situ hybridization protocol for less abundant probes. Opsin-mRNA is localized specifically to the visual receptor cells in the ommatida. No other cells in the brain or the remainder of the body are positive. This is confirmed by Northern blot analysis. The sequence of the receptor, of which we have found two different transcripts, confirms its typical topology, including the seven transmembrane spanning regions and the intracellular carboxy terminus that has potential phosphorylation sites. Our in situ hybridization protocol combines several procedures: the most important points are: (a) the immediate processing of sections after cutting, and (b) the sections are never allowed to dry out once the procedure was started. Our protocol has a much higher sensitivity, using approximately 50 x lower concentrations of probe compared to published protocols. In addition to the detection of opsin-mRNA, it has been successfully applied to the detection of the low abundant insulin receptor homologue. Furthermore, Aedes aegypti probes were visualizing a similar tissue specificity when applied to the malaria mosquito Anopheles albimanus.

Aedes↗
PubMed1995

[A look back at 2 mumps outbreaks].

Two studies are presented. The first one concerns a mumps outbreak in a kindergarten in Geneva in June 1991. Of 26 children, nine (34.6%) got mumps. Of nine children vaccinated with the Rubini vaccine strain, seven had the disease as opposed to only one of 14 children vaccinated with the Urabe strain. The vaccine efficacy of the Rubini strain was estimated at 22% with a 95% confidence interval of -10% to 45%. The second study concerns a cluster of 112 mumps patients seen by a pediatrician in the Bernese Jura region between September 1992 and May 1993. A case-control study was carried out resulting in a vaccine efficacy estimate of 50% with a 95% confidence interval of -19% to 81%. Of the cases, 51 (45.5%) had been vaccinated against mumps, 50 of them (98%) with the Rubini vaccine strain. Of the controls, 30 (61.2%) had been vaccinated, 86.7% of them with Rubini. Methodological problems of case selection and their possible effects on the estimated vaccine efficacy are discussed. The results of these two studies have been confirmed by more recent investigations. In retrospect, we therefore conclude that small studies can serve as early indicators for epidemiological evidence and that they can be finally integrated into a more complete picture.

Child↗
PubMed1988

[A 10-year follow-up of cases with anorexia first hospitalized in the Canton of Zürich].

Out of all 38 anorexia nervosa patients hospitalized for the first time in a private or state hospital for pediatrics, internal medicine or psychiatry in the Canton of Zurich during the period 1973-1975, 28 cases could be assessed 10 years later using a semistructured interview. Catamnestic data were categorized according to Morgan and Russel (1975) in a general outcome score and an average outcome score. Regarding somatic and psychosocial dimensions, 11% of the patients examined can be considered symptom-free, 71% improved and 14% unchanged. One patient (4%) had died from the sequelae of anorexia. 64% increased in weight, nevertheless more than half of the patients had disturbed eating behavior at the time of this catamnestic study. An equally frequent finding was considerable impairment of psychologic well-being chiefly reflected in anxiety and depression. The time necessary to attain the normal weight range had varied between a few months and 11 years. Of 8 variables often claimed to be prognostic in the literature on the course of anorexia nervosa, only a short duration of illness before hospitalization was shown to be relevant. The patients with good or medium outcome most often consider psychotherapy or a partner relationship a decisive factor in the favorable course of their eating problem.

Adult↗