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Biomedical subjects

G Stein

Publications and source records attributed to G Stein.

At least 307 records · Page 17Linked to original sources
PubMed1984

Histone gene expression in human diploid fibroblasts: analysis of histone mRNA levels using cloned human histone genes.

The cellular abundance of H2A, H2B, H3 and H4 histone mRNA sequences was determined prior to and at various times after stimulation of non-dividing human diploid fibroblasts to proliferate. The representation of histone mRNAs was quantitated by electrophoretic fractionation of total cellular RNAs, diffusion transfer to nitrocellulose and hybridization with a series of cloned genomic human histone sequences. The levels of mRNAs for the four core histones were observed to be temporally and quantitatively coupled with both DNA replication and histone protein synthesis. Therefore, a contribution to the regulation of histone gene expression at a transcriptional level is suggested.

Cells, Cultured↗
PubMed1984

Cell cycle regulation of human histone H1 mRNA.

A cloned genomic DNA fragment containing a human histone H1 gene has been used to analyze histone H1 gene expression in two human cell lines (HeLa S3 and WI-38). The cellular abundance of histone H1 mRNA was compared with that of core (H2A, H2B, H3, and H4) histone mRNAs as a function of the cell cycle: core and H1 histone mRNA levels are related both to each other and to the apparent rate of DNA synthesis and are rapidly destabilized after DNA synthesis inhibition. The use of three synchronization protocols, and of transformed and normal diploid cells in culture, suggests that the detected core and H1 histone mRNA levels are regulated by similar mechanisms in continuously dividing human cell lines and nondividing cells stimulated to proliferate.

Cell Cycle↗
PubMed1984

Coordinate replication of members of the multigene family of core and H1 human histone genes.

Cells of the K562 human erythroleukemia cell line were obtained in different stages of the cell cycle by centrifugal elutriation. The cells had been previously labeled for 2 hr with BrdUrd so that BrdUrd-DNA synthesized during four different selected intervals of the S phase could be isolated. This DNA was used to determine the temporal replication during S phase of EcoRI segments containing histone genes. Cloned human genomic segments containing the core histone genes (H2A, H2B, H3, and H4), H2A and H2B pseudogenes, and the H1 gene were prepared. The genomic inserts were excised from these plasmids, nick-translated, and used as hybridization probes. The results with different probes compared on the same and on independently prepared DBM-paper transfers indicate that all of these histone genes replicate during the first half of the S phase. These genes were not among the earliest to replicate in the K562 cell line. Similar studies were carried out with HeLa cells in which EcoRI segments containing the H4 histone and H2A and H2B pseudogenes were found to replicate during the first half of the S phase. These histone genes replicate during the interval of the S phase when histone mRNA appears in the cytoplasm at the maximal rate. The possible relationship between these events is discussed.

Base Sequence↗
PubMed1984

Evidence for a human histone gene cluster containing H2B and H2A pseudogenes.

Not all members of the human histone gene family are functional. We have isolated a human H2B pseudogene that contains alterations in the protein-coding sequences as well as in the 3' and 5' flanking sequences that preclude expression of a functional H2B histone protein. There are three modifications in the amino acid-coding region: a single-base deletion producing a frame shift, a single-base substitution resulting in a codon change from serine to tryptophan (an amino acid not present in histones), and the absence of a stop codon. Analysis of nucleotide sequences upstream from the AUG start signal indicates the absence of a "TATA" box and other putative consensus regulatory sequences. In the 3' flanking region, a highly conserved block of 22 nucleotides that exhibits hyphenated dyad symmetry is displaced downstream. Within the same genomic segment, the adjacent H2A histone gene is missing 12 nucleotides, resulting in a deletion of four amino acids in a highly conserved region of the protein.

Amino Acid Sequence↗
PubMed1984

Headaches after childbirth.

71 women were examined daily for the presence of headache in their first post partum week. Post natal headache (PNH) occurred in 27, (39%) of the women and was most frequent on days 4-6 post partum. PNH was significantly associated with a previous or family history of migraine and pre-menstrual migraine. Although 83% of those with PNH had a migraine diathesis, they did not describe their headache as one of their usual migraines as it was considerably milder. Headaches were more frequent among multigravida but as rather more multigravida had a previous migraine diathesis this may reflect a sampling bias. PNH subjects had significantly more tension and depression suggesting that at least some PNH may be tension headache. Around 3 or 4 days post partum, women began to lose weight and the onset of headache often coincided with the start of this weight loss. 12 women with, and 12 without PNH took part in a metabolic study, and collected sequential 24 h urine samples from days 2-7 post partum. Potassium and oestrogen excretion were increased on day 3, and progesterone on days 3, 4 and 5. Differences in the excretion pattern of these hormones might reflect small changes in renal function and further work measuring plasma hormone levels could help to clarify this. PNH, like pre-menstrual headache and pill withdrawal headache may represent a further example of the triggering effect that a fall in sex hormone level has on the migraine diathesis.

Adolescent↗
PubMed1984

[Cytomegalovirus infections in dialysis patients].

In 42 patients from our chronic haemodialysis programme (21 men, 21 women at an average age of 39.1 +/- 2.1 years and with an average period of dialysis of 20.5 +/- 3.5 months) IgG and IgM antibodies against CMV late antigens and IgG antibodies against CMV early antigens were estimated; in 42 healthy subjects with the same age and sex structure IgG antigens against CMV late antigens were estimated. No difference in antibody prevalence was found between the two groups; around 80% of those examined had suffered an infection with CMV. Whereas primary infections are not significant in dialysis patients, reactivations of latent CMV infections, which can be accompanied by the most varying symptoms, seem to occur more frequently. Transplantats from seropositive donors are dangerous for seronegative patients.

Adult↗
PubMed1984

[Diagnosis of vitamin B12 deficiency in chronic kidney insufficiency].

It is difficult to assess the vitamin B12 metabolism in chronic renal insufficiency. In varying numbers out of a total of 88 nephropathy patients with varying degrees of insufficiency (22 patients without restriction of kidney function, 53 patients with chronic renal insufficiency in the stage of compensated retention and 13 haemodialysis patients) the Schilling test was performed and the serum vitamin B12 level was measured in fasting and 4, 6, 8 and 10 hours after oral administration of 2000 micrograms of vitamin B12. Regardless of the volume of urine, the Schilling test must be treated critically with serum creatinine values between 150 and 300 mumol/l and beyond 300 mumol/l it is no longer of diagnostic value. Serum vitamin B12 measurement after oral administration of 2000 micrograms of vitamin B12 allows vitamin resorption in the ileum to be qualitatively demonstrated on the basis of the curve. In most renal insufficiency patients the serum vitamin B12 level was increased, but this does not exclude the possibility of vitamin B12 deficiency.

Adolescent↗
PubMed1984

Pharmacokinetic and pharmacodynamic effects of furosemide in patients with impaired renal function.

Three groups of patients with kidney diseases were investigated: I. creatinine in serum less than 100 mumol/l, II. creatinine in serum 100-250 mumol/l, III. creatinine in serum greater than 250 mumol/l. After intravenous injection of 40 mg and 80 mg furosemide, serum concentrations and urinary excretion of the unchanged drug were measured fluorometrically. Moreover, urinary excretion of water, electrolytes, creatinine and urea nitrogen were estimated in order to check the pharmacodynamic effect of the drug. The pharmacokinetic parameters calculated were similar in group I and II. In group III t 1/2 was prolonged, renal clearance of furosemide was diminished. The diuretic effect of furosemide was noticeable during the first 4 hours following the injection of 40 mg in all 3 groups. Doubling the dose did not enhance the effect. Creatinine and urea nitrogen excretion in urine were not influenced by furosemide.

Creatinine↗
PubMed1984

[Pharmacokinetics of the sulfonamide-trimethoprim combinations Berlocombin and Sulprim in patients with various degrees of kidney dysfunction].

Patients with normal and decreased kidney function were treated with an initial dose of 4 tablets Berlocombin and following with a dose of 2 tablets for 10 d in a 12 h period. The dialysis patients got only once the initial dose. The kinetic parameters were calculated by means of a one compartment model. Independend on the kidney function the minimum therapeutic serum concentrations of 1 microgram/ml at trimethoprime and of 20 micrograms/ml at the sulphonamides were reached during the first hours after medicament application. At all patients the urine concentration of trimethoprime were some times over the minimum therapeutic concentration. The individually found maintenance doses fluctuate between 2 tablets each 12 h and 1 tablet each 24 h. At patients with serum creatinine levels greater than 3 mg/100 ml (greater than 265 mumol/l) 1 tablet each 12 h is sufficient as maintenance dose. At a higher degree of kidney function decreasing (serum creatinine greater than 6 mg/100 ml (greater than 530 mumol/l] cumulating of the sulphonamide metabolites in the serum is found. The evaluated elimination velocity of the investigated sulphonamides during the hemodialysis was higher than that at patients with normal kidney function. The elimination rate of trimethoprime during the dialysis is in the same region as at patients without any kidney diseases.

Drug Combinations↗
PubMed1984

[Diagnostic and therapeutic attempts in so-called progressive dialysis encephalopathy].

57 patients from a chronic intermittent haemodialysis programme underwent 198 EEG examinations over a period of 5 years with follow-up. The results show that regular EEG examinations allow incipient dialysis encephalopathy to be recognized already at the pre-clinical stage. Whereas therapeutic measures always had no effect on the full clinical picture of dialysis encephalopathy and all patients died, in all but one case lengthening the dialysis time prevented the syndrome from reaching the clinical stage and in 6 cases EEG changes were reversed.

Adult↗
PubMed1983

Influence of DNA synthesis inhibition on the coordinate expression of core human histone genes during S phase.

Core histone mRNA metabolism has been examined in S phase HeLa cells recovering from DNA synthesis inhibition by 1 mM hydroxyurea. Using cloned human histone genes as probes for histone mRNA quantitation, the response to and recovery from DNA synthesis inhibition is shown to depend on the position of the cell with respect to the initiation of DNA replication. The incorporation of 3H-uridine into multiple histone mRNAs in recovering cells does not exceed preinhibition levels, and as this incorporation is maximal in early S phase, the synthesis of core histone mRNA is apparently related to the ordered replication of the genome. The total histone mRNA present in interrupted S phase cells after recovery is not significantly different from that present in control cells, and a temporal and functional coupling between histone mRNA levels and the relative rate of DNA synthesis is maintained in perturbed cells.

DNA Replication↗
PubMed1983

Structure and in vitro transcription of a human H4 histone gene.

A human H4 histone gene was isolated and the nucleotide sequences of the mRNA coding as well as the 5' and 3' flanking regions were determined. No intervening sequences were found in this gene. A series of sequences which have been assigned putative regulatory roles in histone genes and/or in other genes were identified both upstream and downstream from the H4 histone protein coding region. Deletion mutants were constructed by BAL-31 nuclease digestion of sequences in the 5' flanking region of this H4 histone gene and were assayed in an in vitro transcription system. No regions upstream from the TATA box were required for site specific initiation in vitro. Data are presented which suggest that sequences located downstream from the 3' end of the coding region may influence the in vitro transcription of this human H4 histone gene.

Amino Acid Sequence↗
PubMed1983

Crosslinking of chromosomal proteins to DNA in HeLa cells by UV gamma radiation and some antitumor drugs.

Immunochemical techniques were used to investigate the protein-DNA crosslinking by ultraviolet (UV) and gamma radiation as well as 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) or cis- and trans-diamminedichloroplatinum II (cis-DDP and trans-DDP). Antisera to 0.35 M NaCl extract and 0.35 M NaCl residue of HeLa nuclei were employed. Both gamma and UV irradiation, exposure to cis- or trans-DDP and, to a lesser extent, BCNU, resulted in crosslinking of various antigens to the DNA. Although several antigens were crosslinked by all the employed agents, other exhibited agent-specific crosslinking patterns.

Carmustine↗
PubMed1983

Coordinate regulation of multiple histone mRNAs during the cell cycle in HeLa cells.

Core histone gene expression in HeLa S3 cells has been examined as a function of the cell cycle using cloned human histone gene probes. Total cellular histone mRNAs were analyzed by Northern blot analysis, and their relative abundance shown to be temporally coupled to DNA synthesis rates in S phase. The in vivo incorporation of 3H-uridine into at least fifteen heterologous histone mRNAs (in one hour pulse intervals at various times in the cell cycle), was monitored by hybrid selection. Hybridized RNAs were eluted and resolved electrophoretically to give both a quantitative and qualitative assay for multiple mRNA species. Maximal incorporation of 3H-uridine into histone mRNAs precedes their maximal accumulation, indicating that transcriptional regulation is predominant in early S phase. The turnover of histone mRNAs in late S occurs in the presence of a reduced apparent transcription rate, indicating that post-transcriptional regulation is predominant in late S. All the detected multiple histone mRNAs are coordinately regulated during the HeLa cell cycle.

Cell Cycle↗
PubMed1983

Prevention of recurrent uric acid and calcium oxalate stones by administration of the xanthine oxidase inhibitors Milurit 100 and Milurit 300.

Disturbances in purine metabolism with hyperuricaemia and/or hyperuricosuria are a risk factor in uric acid and Ca oxalate stone formation. By way of a competitive xanthine oxidase inhibition, the formation of uric acid is reduced by allopurinol. In investigations on two groups of patients, Milurit could be demonstrated to decrease the uric acid levels in serum and urine. No differences could be seen in the dosages of 3 x 100 mg or 1 x 300 mg Milurit. Therefore, in stone recurrence prevention, the administration of Milurit 300 is recommended.

Adolescent↗
PubMed1983

[In vitro studies on the adsorption of various resins of the Wofatit type for drugs].

The capacities of the resins Wofatit Y 29, Y 55 and Y 56 (VEB Chemiekombinat Bitterfeld) to adsorb various medicaments were compared with that of the resin XAD-4. Methaquelone, diazepam, krotylbarbital, promazine phosphate and ethyloxamine were used as test substances. The resin Y 56 proved to have an adsorption capacity similar to that of XAD-4 (e.g. maximum saturation for methaquelone 98%, half-maximum saturation at 7 minutes). In further tests on various batches of this resin the best results were given by the resin Y 56/7. Adsorption was quite clearly shown to be dependent on concentration. At a blood-flow of 100 ml/min clearance values of 34.5 ml/min for krotylbarbitol and 22.1 ml/min for methaquelone were calculated. According to these findings the resin Y 56/7 is suitable for further testing in a haemoperfusion system with a view to clinical use.

Barbiturates↗