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Biomedical subjects

P Hirsch

Publications and source records attributed to P Hirsch.

96 records · Page 6Linked to original sources
PubMedDate not supplied

Molecular genetic evidence for early evolutionary origin of budding peptidoglycan-less eubacteria.

Recent studies on the cell wall composition of budding, non-prosthecate bacteria have shown that representatives of the genera Planctomyces and Pasteuria (sensu Staley, 1973) lack the peptidoglycan moiety, which is the characteristic feature of eubacterial cell walls, but possess an as yet unidentified protein sheet instead; in this respect Planctomyces and Pasteuria strains resemble certain archaebacteria more than eubacteria. To determine their phylogenetic positions, the 16S ribosomal RNAs of three budding, peptidoglycan-less strains with and without stalks were subjected to partial sequence analyses. As we report here, the comparison of data with those obtained from about 320 eubacterial and 40 archaebacterial strains revealed that the strains investigated are not members of the archaebacterial kingdom but represent an ancient line of descent of the eubacterial kingdom. Furthermore the diphtheria toxin reaction of Planctomyces and Pasteuria shows that they behave like eubacteria.

Bacteria↗
PubMedDate not supplied

TT virus infection in chronic liver disease.

BACKGROUND/AIMS: The exact role of the novel hepatotropic TT virus regarding the etiology of viral hepatitis, as well as the progression towards chronic liver disease has as yet not been defined. Moreover, the contribution of TTV infection to the course of chronic hepatitis B or C virus infections also still awaits clarification. Hence, the aim of our study was to investigate the impact of TTV infection on clinical severity and histology of chronic liver disease originating from HBV and/or HCV infections in Thai patients concomitant with the determination of TTV's association with non-B, non-C chronic liver disease and compared to its prevalence among voluntary blood donors. METHODOLOGY: DNA was extracted from the sera collected from 115 hepatitis B patients, 41 hepatitis C, and 48 negative for either viral marker, who had all been diagnosed with chronic liver disease ranging from chronic hepatitis over cirrhosis to hepatocellular carcinoma. The sera obtained from 200 voluntary blood donors served as controls. TTV DNA was amplified by seminested polymerase chain reaction (PCR) employing primers derived from the genome's most conserved region. The PCR products were analyzed by gel electrophoresis. Liver function tests were performed by means of a chemical analyzer. RESULTS: TTV DNA was detected in 20% of the HBV-positive and 19.5% of the HCV-positive chronic liver disease patients. Within the group of patients seronegative for both viral markers, TTV was detected in 8.3%. Furthermore, its DNA was identified in 6.8% of the HCC patients and finally, in 7% of the blood donors. Yet, no significant differences between TTV infected and non-infected patients were found as to demographic data, assumed source of infection, biochemical abnormalities, or severity of liver histology. CONCLUSIONS: TTV appears to be highly prevalent on a worldwide scale but regarding etiology of and progression towards serious liver disease, its contribution seems to be minor if not altogether non-existent. Hence, regarding clarification of its clinical significance, further studies are certainly required.

Adolescent↗
PubMedDate not supplied

Transfusion transmissible virus TTV and its putative role in the etiology of liver disease.

TTV, the transfusion transmissible hepatitis virus infects mainly patients at risk for parenteral exposure and hence, prone to develop chronic liver disease, as well as healthy populations worldwide. Most TTV infections appear to occur parenterally, with viremia detected frequently in blood donors and blood products. The substantial proportion of asymptomatic individuals never exposed to blood-borne agents, and its high prevalence among healthy subjects implicates the fecal-oral route as another potential for transmission. According to the TTV DNA levels detected in liver tissue, it apparently replicates in hepatocytes, and TTV DNA is present in sera of patients with posttransfusion hepatitis of unknown etiology closely correlated with ALT levels. However, TTV initiating the development of chronic liver disease or causing posttransfusion hepatitis could not be confirmed, as most patients positive for TTV DNA remain asymptomatic and those progressing towards chronic liver disease are invariably coinfected with either the hepatitis B or C virus. Also, TTV coinfection does not aggravate the symptoms associated with hepatitis B or C. Similarly, it does not cause posthepatitis aplastic anemia, and high-risk patients can immunologically clear the viral DNA. In conclusion, being widely distributed and apparently nonpathogenic, TTV might represent an opportunistic but innocent virus reminiscent of hepatitis G virus, with a negligible role in the etiology of chronic liver disease.

DNA Virus Infections↗
PubMedDate not supplied

Hysteroscopy for gamete intrafallopian transfer (GIFT).

Gamete intrafallopian transfer (GIFT) is performed currently using laparoscopy. We report on a pilot-study from 1.1.1987 to 31.12.1987 and from 1.5.1988 to 30.4.1989, in which we used hysteroscopy instead of laparoscopy for the GIFT-procedure. The entering conditions were: unexplained (idiopathic) infertility, failure of previous treatments, proven fertilization capability of the gametes in at least one IVF attempt, and request of the married couple to dispense with laparoscopy during GIFT procedure. Hysteroscopic GIFT was initially performed on hysterectomy specimens, using the Chorionoskop. Continuous flow CO2 through the fallopian tubes did not result in loss of gametes. Twenty-four treatment cycles were performed in 16 patients. In 19 cycles, gametes were transferred into one tube, and in two cycles they were transferred into both tubes. Four of 16 women conceived: one patient delivered at term, three pregnancies ended in a first trimester abortion. These results demonstrate that the hysteroscopic approach to intrafallopian gamete transfer can be successful. However, the technique is demanding and requires extensive training. We conclude that further improvements of hysteroscopic GIFT are needed.

Female↗
PubMedDate not supplied

[Course of pregnancy and labor following in vitro fertilization. A retrospective study of 246 deliveries].

This record concerns the statistical registration and analysis of the courses and developments having taken place in 246 pregnancies and births after in-vitro-fertilization. The cases were registered retrospectively, the degree of registration being 77.2% approximately; the scientific evaluation was carried out on the basis of the BPE 1987. It can be shown that there is an increased incidence of the EPH-gestosis, the clinically relevant placenta insufficiency syndrome, the intrauterine death of fetus, the abruptio placentae and prematurity. As predisposing factors must primarily be seen and discussed the ovarian hyperstimulation being--in most cases--connected with IVF and the higher age of the patients; it can be supposed that the method of fertilization in vitro itself is of minor importance. Its importance in the pathogenesis of abruptio placentae, however, cannot be exactly evaluated so far. The frequency of multiple pregnancies represents a special problem. Though the rate is lower in the examined group than in comparable--that is due to the limited number of collected oocytes--it should be aimed at a further lowering of multiple pregnancy rates.

Adult↗