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Biomedical subjects

F Jelinek

Publications and source records attributed to F Jelinek.

10 recordsLinked to original sources
PubMed1996

Risk of hepatitis C virus (HCV) transmission by anti-HCV-negative blood components in Austria and Germany.

In order to estimate the residual risk of transfusion-transmitted HCV infection, we have analyzed data from transfusion centers in Austria (Vienna) and Germany (Göttingen) from 1990 to 1995. In Vienna, the seroprevalence (RIBA-confirmed third-generation anti-HCV tests) was 0.28% in first-time donors (FTD) and the incidence of seroconversion in repeat donors (RD) was 0.049 (per 100 person years) from 1994 to 1995. In Göttingen, the prevalence of a PCR-confirmed positive third-generation anti-HCV test was 0.22% in FTDs and the incidence was 0.093 (per 100 persons years). A continuous decline of the rate of anti-HCV-positive donations and donors was observed with first- and second-generation anti-HCV tests in the years 1990-1994. The introduction of the third-generation anti-HCV test resulted in increased numbers of anti-HCV positive repeat donors, mainly due to false-positive results. Only 9% of anti-HCV-positive repeat donors were either PCR positive or RIBA positive or or indeterminate. Based on a mathematical model which takes (a) the window period, (b) the false-negative rate of anti-HCV tests, and (c) human and operational errors into consideration, we have calculated the residual risk of HCV infection. We used a window period of 74 days, a sensitivity of 98%, and an error rate of .1%. The residual risk (for third-generation anti-HCV test-negative blood components) was calculated to be 1:9000 (95% confidence interval 1:16390-1:6210) and 1:4800 (95% confidence interval 1:40000-1:1320) for Vienna and Göttingen, respectively, in 1994 and 1995. Since this conservative approach does not take the impact of ALAT screening into account, the actual risk is probably lower.

Adult↗
PubMed1995

Training and search methods for speech recognition.

Speech recognition involves three processes: extraction of acoustic indices from the speech signal, estimation of the probability that the observed index string was caused by a hypothesized utterance segment, and determination of the recognized utterance via a search among hypothesized alternatives. This paper is not concerned with the first process. Estimation of the probability of an index string involves a model of index production by any given utterance segment (e.g., a word). Hidden Markov models (HMMs) are used for this purpose [Makhoul, J. & Schwartz, R. (1995) Proc. Natl. Acad. Sci. USA 92, 9956-9963]. Their parameters are state transition probabilities and output probability distributions associated with the transitions. The Baum algorithm that obtains the values of these parameters from speech data via their successive reestimation will be described in this paper. The recognizer wishes to find the most probable utterance that could have caused the observed acoustic index string. That probability is the product of two factors: the probability that the utterance will produce the string and the probability that the speaker will wish to produce the utterance (the language model probability). Even if the vocabulary size is moderate, it is impossible to search for the utterance exhaustively. One practical algorithm is described [Viterbi, A. J. (1967) IEEE Trans. Inf. Theory IT-13, 260-267] that, given the index string, has a high likelihood of finding the most probable utterance.

Communication↗
PubMed1995

Alterations in G-protein-regulated transmembrane signalling induced in murine myocardium by coxsackievirus B3 infection.

OBJECTIVE: Cardiomyopathy is usually associated with marked alterations in myocardial transmembrane signalling. Although acute viral myocarditis may result in chronic cardiomyopathy in some cases, the possible consequences of viral infection on function of the myocardial signal-transducing complex have not been explored. Therefore, the present study was designed to investigate the G-protein-regulated adenylyl cyclase signalling system in murine myocardium during myocarditis induced by coxsackievirus B3 (CVB3) infection. METHODS: We examined the functional characteristics of adenylyl cyclase as well as the function and distribution of beta-adrenoceptors, m-cholinoceptors and G-proteins in myocardial plasma membranes isolated from the hearts of mice with acute (7 days pi) or late phase (21 days pi) myocarditis and the obtained results were compared with the corresponding data determined in age-matched controls. RESULTS: While the basal adenylyl cyclase activity was not significantly altered, the ability of forskolin, sodium fluoride and GTP gamma S to activate adenylyl cyclase was lowered by about 20% in samples from virus-infected animals. The level of Gs alpha in myocardial plasma membranes as well as the functional activity of Gs alpha was not affected by viral infection, but the Gi alpha content was increased by about 20%. The total number of beta-adrenoceptors in myocardial plasma membranes increased by about 12-15% due to higher content of the beta 2-adrenoceptor subtype. Although the agonist-binding parameters of beta-adrenoceptors were not significantly altered, the ability of these receptors to mediate stimulation of adenylate cyclase was markedly diminished (by 56-80%). The total number of m-cholinoceptors in samples derived from virus-infected mice increased considerably (by 29-59%) and a significant proportion of the receptors shifted to a higher affinity status, but their ability to transduce agonist signals was impaired. CONCLUSIONS: These data are the first to demonstrate that several different sites of the myocardial G-protein-regulated adenylyl cyclase signalling complex are significantly altered in acute as well as in late phase of CVB3-induced myocarditis.

Acute Disease↗
PubMed1994

Multiple osteomas in mice.

Osteomas (dense compact neoplasms of mature bone tissue) are rare in nearly all strains and stocks of mice. Of 224 Him:OF1 mice maintained until natural death or until terminally ill, 116 (51.8%) had one or more osteomas. Osteomas had a predilection for the skull and the larger bones of the limbs. Plasma alkaline phosphatase concentrations were elevated significantly in osteoma-bearing mice (446 +/- 153 U/liter versus 206 +/- 65 U/liter in age-matched controls without osteomas). Only very large osteomas resulted in clinical signs, and longevity was not shortened. Histologic examination showed clearly separated dense bony tissue irregularly arranged and forming a mosaic pattern, with distinct cement lines and medullary spaces filled with fibroreticular connective tissue. Electron microscopic examination revealed virus-like structures in osteoblasts, osteocytes, and fibroblasts and in the place of remnants of necrotic cells.

Animals↗
PubMed1989

[Acute and subacute toxicity of antineoplastic Pt(II) and Pt(IV) coordination compounds in laboratory rodents].

After single i.v. administration of cis-diammine-platinum(II)-lactate cis-diammine-platinum(II)-lactate, L cis-diammine-platinum(II)-dilactate trans-dihydroxy-cis-dichlorodiammine-platinum(IV), the LD50 values have been calculated to range between 80 and 130 mg/kg in mice, and between 22 and 45 mg/kg in rats. The LD50 of cis-DDP amounted to 17 mg/kg and 6.6 mg/kg, respectively. Likewise, the compounds have been found to be about 3 to 5 times less toxic than the standard cis-DDP when administered daily for 5 consecutive days. Since the kidneys, the bone marrow, the lymphatic tissue and the intestinal tract have been proved to be the main target organs, the profile of the toxic action of the Pt(II)-complexes seems to be similar to that of cis-DDP. Additionally, the Pt(IV) compound has been found to be toxic to the pancreas, the liver and the salivary glands. With regard to the antineoplastic activity the more soluble lactates of cis-DDP showed a smaller therapeutic index compared to cis-DDP.

Animals↗
PubMed1983

[Regional proliferative changes in the intestines and intestinal adenocarcinoma and lymphoma in golden hamsters with "wet tail"].

A group of 637 golden hamsters [Mesocricetus auratus] was studied and 64 of them found suffering from wet tail syndrome. They had a regional epithelial proliferation of the gut often reminding of a tumour associated with unspecified bacilliform organisms in enterocytes. Three adult females showed a similar lesion lacking of microbes with intestinal adenocarcinoma instead. Its diffuse growth reaching mesentery was combined with secondaries in mesenteric lymph nodes. Nine older hamsters showed a malignant intestinal lymphoma in similar conditions. Mutual relations of the findings were discussed. Wet tail syndrome seemed to be an intestinal precancer.

Adenocarcinoma↗
PubMed1979

[Papovavirus papillomatosis in beagles].

Canine papillomatosis was diagnosed in 5 out of 12 dogs of the beagle race, aged three to four months, two weeks after arrival from a breeding station. The histological as well as electronmicroscopical findings were typical of the disease.

Animals↗