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Biomedical subjects

I Hirsch

Publications and source records attributed to I Hirsch.

At least 109 records · Page 6Linked to original sources
PubMed1982

Late onset of total eversion of the upper eyelids.

A case of total eversion of both upper eyelids of late onset is reported. There were no associated ocular or general anomalies. No apparent cause was found. The treatment was directed toward diminishing the swelling of the lids and preventing corneal involvement, secondary infections, and epidermalization of the conjunctiva. Within the first week, the eyelids returned to their normal position. In a three-month follow-up period, no complication or other anomalies were found.

Age Factors↗
PubMed1981

Presence of Epstein-Barr virus DNA in tonsillar tissues.

Sera from 48 tonsillar carcinoma (TC) patients, 48 matched controls and 16 recurrent exudative tonsillitis (RET) patients were examined for the presence of Epstein-Barr virus (EBV) associated nuclear antigen (EBNA), early antigen (EA) and virus capsid antigen (VCA). Higher prevalence and significantly higher antibody titres against all three EBV-associated antigens were observed in TC patients in comparison with controls and RET patients. Patients suffering from anaplastic TC had higher titres of antibodies against VCA and EA than TC patients with other histological diagnoses. Five out of 11 TC biopsies obtained from 9 patients were positive for EBV DNA at levels of 0.17, 4 to 5, 15 to 18 and in two cases 3 EBV genome equivalents per cellular genome. Among 16 RET patients, 4 were found positive at levels not exceeding 2.17 EBV genome equivalents per cellular genome. Higher titres of antibody against all EBV antigens were found in TC and RET patients with EBV DNA-positive tonsillar tissue than in those with EBV DNA-negative tonsillar tissue.

Adult↗
PubMed1980

Interaction of EBNA with anti-EBNA antibody and DNA.

Binding of Epstein-Barr-virus-determined nuclear antigen (EBNA) to acid-fixed nuclei could be prevented by exposing EBNA to anti-EBNA antibodies. While EBNA is eluted from acid-fixed nuclei by 0.4 M NaCl, it was not eluted even by 1.5 M NaCl if EBNA bound to acid-fixed nuclei had been exposed to anti-EBNA antibody. In this case the reaction was abolished, and EBNA was at least partially eluted by 0.2 M glycine buffer, pH 2.8, or by 3 M NaSCN. EBNA not exposed to antibody was completely eluted from acid-fixed nuclei by treatment with a solution containing 200 microgram of DNA per 1 ml of isotonic buffer, pH 6.5; however, after treatment with antibody, EBNA was not eluted by DNA.

Antibodies, Viral↗
PubMed1980

Binding of SV40 tumour antigen and Epstein-Barr-virus nuclear antigen to isolated acid-fixed nuclei.

SV40 tumour antigen (TA) bound to methanol-acetic-acid-fixed interphase nuclei and metaphase chromosomes. This reaction was visualized by the anti-complement immunofluorescence test. The reaction was negative when the nuclei had been treated with deoxyribonuclease prior to the addition of antigen, or when TA-antibody negative serum had been used. In parallel tests TA and Epstein-Barr virus nuclear antigen were examined. Both the binding patterns and the optimum conditions for the reaction were similar.

Animals↗
PubMed1979

Blocking of acid-fixed nuclear binding of Epstein-Barr virus nuclear antigen (EBNA) by different DNA species.

Treatment of Epstein-Barr virus-determined nuclear antigen (EBNA) with DNA resulted in blocking of its ability to convert acid-fixed EBNA-negative cell nuclei to an EBNA-positive form. Epstein-Barr virus (EBV) DNA, herpes simplex virus type 2 (HSV-2) DNA and DNA isolated from three lymphoblastoid cell lines differed in their potency to block this reaction. EBV DNA was found to be about three times more effective than cellular DNAs in abolishing the ability of DNA-cellulose-purified EBNA to convert acid-fixed nuclei to the EBNA-positive form; the effect of HSV-2 DNA was of intermediate character. No difference was found between the blocking potency of DNAs isolated from EBV-genome-negative Ramos cells and EBV-genome-positive Raji and P3HR-1 cells.

Antigens, Viral↗
PubMed1979

Increased RNA and heme synthesis in mouse erythroid precursors by parathyroid hormone.

The in vitro effect of parathyroid hormone (PTH) on RNA and heme synthesis by embryonic mouse liver erythroid precursors was examined. PTH produced a dose-dependent effect on RNA synthesis. A maximal increase of 60 +/- 16% (p less than 0.02) was observed with 1.0 U PTH/ml, whereas with higher concentrations a significant decline was found. Furthermore, PTH stimulated heme synthesis after 24 h of incubation. The maximal enhancement of 32 +/- 7% (p less than 0.01) was observed with 0.5 U PTH/ml, a lower effect was obtained with 1.0 U PTH/ml, while 2.0 U PTH/ml caused a pronounced decrease of heme synthesis. These data indicate that PTH affects directly the erythroid precursors by a mechanism similar to that of erythropoietin. The inhibitory effect on the RNA synthesis observed with large doses of PTH may explain at least one of the causes of the anemia reported in patients with primary hyperparathyroidism.

Animals↗
PubMed1978

Study of Epstein-Barr virus-determined nuclear antigen (EBNA) by chromatography on fixed cell nuclei.

Low ionic strength (50 to 100 mM NaCl) and pH 6.0 were found to be optimal conditions for in vitro conversion of Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA)-negative nuclei to EBNA-positive nuclei by addition of the complement-fixing (CF) antigen extracted from Raji cells. In vitro conversion of nuclei to EBNA-positively was sensitive to DNase but not to RNase treatment. This suggests that nuclear DNA is a specific target substance to which EBV-CF antigen binds. If nuclei were fixed with methanol/acetic acid and subsequently treated with 0.6 M NaCl, EBNA could be eluted from in vitro-converted Ramos nuclei with 0.3 and 0.4 M NaCl. The same conditions were also found to be optimal for the adsorption and elution of EBV-CF antigen in DNA-cellulose chromatography. This indicates that the DNA-binding properties of EBNA antigen can be studied by "chromatography" on fixed nuclei followed by the ACIF test. The obvious advantages of this method over chromatography on DNA-cellulose are its simplicity, the possibility of testing many samples in one experiment and, especially, the use of minimal amounts of material. Significant differences in elution patterns for EBNA were found when nuclei derived from different cell lines (Ramos, Raji, and P3HR-1) were converted in vitro to EBNA-positivity. EBNA is eluted from in vitro-converted nuclei of EBV genome-positive P3HR-1 cells at an almost 0.1 M higher concentration of NaCl than is necesssary for a similar degree of elution from nuclei of EBV genome-negative Ramos cells.

Acetates↗
PubMed1977

Syntheses of virus-induced thymidine kinase and viral DNA in herpes simplex type 1 virus-infected chick embryo fibroblasts.

Herpes simplex virus type 1, strain Kupka, did not replicate in chick embryo fibroblasts (CEF), but the infection was followed by the development of cytopathic changes. This effect could be abolished by UV irradiation of the virus. Virus-induced thymidine kinase was synthesized in the infected cells reaching a maximum level at 24 hours post infection (p.i.). In the presence of cytosine arabinoside, thymidine kinase synthesis was enhanced. This suggested that the late (post-replicative) viral function, which turns off thymidine kinase synthesis, was expressed in the infected CEF untreated with the drug. HSV type 1 laboratory strains Kupka and KOS were capable of inducing the synthesis of virus-specific DNA in CEF. But in CEF infected with fresh type 1 virus isolates replication of viral DNA was not observed.

Animals↗
PubMed1976

Replicating DNA of herpes simplex virus type 1.

Newly synthesized herpes simplex virus type 1 DNA yielded a heterogeneous sedimentation profile in neutral sucrose gradients, with the main peak occurring at approximately 40S. Components sedimenting slower than virion DNA and a rapidly sedimenting intracellular HSV DNA were also observed. Both the low-molecular weight and the rapidly sedimenting components seemed to be precursors of virion DNA: they almost completely disappeared after a 60-min chase of a 3-min pulse of 3H-thymidine, and were converted into DNA which cosedimented with virion 32P-labeled DNA. However, sedimentation analysis in alkaline sucrose gradients showed that a 60-min period was insufficient for completing the maturation of HSV DNA. Cleavage of parental DNA molecules was observed in neutral sucrose gradients after infection with 3H-thymidine-labeled virions. No evidence for the formation of covalently closed circles during the replication process was obtained. The presence of single-stranded regions in the replicative form of HSV DNA was revealed. Some of the short-pulse (30 sec) labeled HSV DNA (26.1%) was eluted from hydroxylapatite columns with the properties of single-stranded DNA, and 22% of its trichloroacetic acid precipitability was susceptible to single-strand specific S1 nuclease treatment. Pulse-chase experiments indicated that the life-time of this single-stranded component in nascent DNA was probably not longer than 3 min. A small proportion of single-stranded regions, however, survived for longer periods. Almost all of the newly synthesized short-pulse-labeled HSV DNA exhibited an affinity for nitrocellulose filters. This affinity, which was S1 nuclease-sensitive, gradually decreased with prolongation of the time of the chase. After chasing the pulse for 1 h, the attachment of newly synthesized DNA was comparable with virion DNA.

Cell Line↗
PubMed1974

Ribonucleotides linked to DNA of herpes simplex virus type 1.

Cells of a continuous cell line derived from rabbit embryo fibroblasts were infected with herpes simplex type 1 virus (HSV-1) and maintained in the presence of either [5-(3)H]uridine or [methyl-(3)H]thymidine or (32)PO(4) (3-). Nucleocapsids were isolated from the cytoplasmic fraction, partially purified, and treated with DNase and RNase. From the pelleted nucleocapsids, DNA was extracted and purified by centrifugation in sucrose and cesium sulfate gradients. The acid-precipitable radioactivity of [5-(3)H]uridine-labeled DNA was partially susceptible to pancreatic RNase and alkaline treatment; the susceptibility to the enzyme decreased with increasing salt concentration. No drop of activity of DNA labeled with [(3)H]thymidine was observed either after RNase or alkali treatment. Base composition analysis of [5-(3)H]uridine-labeled DNA showed that the radioactivity was recovered as uracil and cytosine. In the cesium sulfate gradient, the purified [5-(3)H]uridine-labeled DNA banded at the same position as the (32)P-labeled DNA. The present data tend to suggest that ribonucleotide sequences are present in HSV DNA, that they are covalently attached to the viral DNA, and that they can form double-stranded structures.

Alkalies↗