Search PubMed⌕ Search

Biomedical subjects

S Albert

Publications and source records attributed to S Albert.

At least 73 records · Page 4Linked to original sources
PubMed1995

Production and purification of Japanese quail ovalbumin as fusion protein with glutathione S-transferase in Escherichia coli.

A plasmid encoding a fusion protein interlinked by thrombin recognition sequence between glutathione S-transferase and Japanese quail ovalbumin (without 40 amino acid residues from the 5'-end of the ORF) has been constructed, employing the expression system pGEX-2T. The deglycosylated fusion protein (64 kDa) was purified by affinity chromatography on glutathione agarose beads, analyzed by SDS-polyacrylamide gel electrophoresis, immunochemically detected with antiserum raised against Japanese quail ovalbumin and tested for its stability.

Animals↗
PubMed1994

Purification and characterization of human ribonuclease HII.

A ribonuclease H activity from human placenta has been separated by ion exchange chromatography from the major RNase HI enzyme. Additional chromatographic steps allowed further purification, more than 3,000 fold compared to the crude extract in which it represents about 15% of the total RNase H activity. The enzyme requires Mg2+ ions for its activity, is strongly inhibited by the addition of Mn2+ ions or other divalent transition metal ions, and exhibits a pH optimum between 8.5 and 9. It shows a strong sensitivity to the SH-blocking agent N-ethylmaleimide. It has a strict specificity for double-stranded RNA-DNA duplexes and exhibits neither single-stranded nor double-stranded RNase (or DNase) activities. Therefore, this enzyme displays the characteristics of class II RNase H and is now termed RNase HII. Renaturation gel assays and gel filtration experiments proved a monomeric structure for the active enzyme with a native molecular weight of about 33 kDa. The human RNase HII acts as an endonuclease and releases oligoribonucleotides with 3'-OH and 5'-phosphate ends. It is therefore a candidate for the RNase H-mediated effect of antisense oligodeoxynucleotides.

Base Sequence↗
PubMed1994

Molecular analysis of the helper T cell response in murine interstitial nephritis. T cells recognizing an immunodominant epitope use multiple T cell receptor V beta genes with similarities across CDR3.

Anti-tubular basement membrane disease (alpha TBM disease) produces T cell-mediated interstitial nephritis in SJL mice after immunization with renal tubular antigen. Initial mononuclear infiltrates appear in vivo after several weeks, with the subsequent progression to renal fibrosis and end stage renal disease over many months. We have analyzed the fine specificity of the autoreactive helper T cell repertoire in alpha TBM disease through the isolation and characterization of a panel of CD4+ Th1 clones harvested after 1-2 wk from animals immunized to produce disease. All clones capable of mediating alpha TBM disease are directed towards a 14-residue immunodominant epitope (STMSAEVPEAASEA) contained within the target antigen, 3M-1. Evaluation of the T cell receptor (TCR) V beta repertoire used by these autoreactive T cells reveals the use of several V beta genes, but with some preference for V beta 14. Sequencing across the putative CDR3 region of the TCR beta chains suggests that common amino acids at the V beta(N)D beta junction and the D beta(N)J beta junction may contribute to the specific ability of these cells to recognize the immunodominant epitope.

Amino Acid Sequence↗
PubMed1993

Sensitive detection of low levels of ribonuclease H activity by an improved renaturation gel assay.

Renaturation gel assays are good tools to assign enzymatic activities to protein bands. First, proteins are separated by denaturating electrophoresis on substrate-containing gels. Then, following the elimination of the denaturing agent, polypeptides are allowed to renature, thus leading to the degradation of the embedded substrate at positions at which the corresponding activity has moved. Nevertheless, this in situ technique does not only reflect a certain amount of enzyme activity, it also depends upon the ability of an enzyme to renature. Here we present a renaturation gel assay procedure with an improved sensitivity and discuss the detection of E. coli and human ribonuclease H activities as an example.

DNA Polymerase I↗
PubMed1993

An invertebrate calcium-binding protein of the calbindin subfamily: protein structure, genomic organization, and expression pattern of the calbindin-32 gene of Drosophila.

Antisera against vertebrate calcium-binding proteins cross-react with Drosophila nervous and muscle tissue. We have used an antiserum against carp parvalbumin to isolate from a Drosophila head cDNA library immunopositive expression clones. Tissue in situ hybridization identified a clone that labeled specific neurons and muscles similar to the parvalbumin-like immunohistochemical staining pattern. Five independent cDNAs derive from an mRNA whose open reading frame codes for a 310 amino acid polypeptide. Sequence analysis identifies six EF-hand calcium-binding domains and reveals 42% and 37% homology to chicken calretinin and calbindin D-28k, respectively. Since the positions of 9 out of 10 introns within the ORF are conserved from the Drosophila gene to both vertebrate genes, we conclude that we have identified the first invertebrate member of the calbindin sub-family of calcium-binding protein genes of the EF-hand homolog family. The calbindin-32 gene (cbn) maps to 53E on the second chromosome. It is expressed through most of ontogenesis with a selective distribution in the nervous system and in a few small adult thoracic muscles. The cloning of a Drosophila homolog to vertebrate neuronal Ca(2+)-binding proteins opens new routes to study the so far largely elusive function of these brain molecules.

Amino Acid Sequence↗
PubMed1992

Partial angle inversion recovery (PAIR) MR imaging: spin-echo and snapshot implementation.

The effects of varying the inversion or excitation RF pulse flip angles on image contrast and imaging time have been investigated in IR imaging theoretically, with phantoms and with normal volunteers. Signal intensity in an IR pulse sequence as a function of excitation, inversion and refocusing pulse flip angles was calculated from the solution to the Bloch equations and was utilized to determine the contrast behavior of a lesion/liver model. Theoretical and experimental results were consistent with each other. With the TI chosen to suppress the fat signal, optimization of the excitation pulse flip angle results in an increase in lesion/liver contrast or allows reduction in imaging time which, in turn, can be traded for an increased number of averages. This, in normal volunteers, improved spleen/liver contrast-to-noise ratio (9.0 vs. 5.7, n = 8, p less than 0.01) and suppressed respiratory ghosts by 33% (p less than 0.01). Reducing or increasing the inversion pulse from 180 degrees results in shorter TI needed to null the signal from the tissue of interest. Although this decreases the contrast-to-noise ratio, it can substantially increase the number of sections which can be imaged per given TR in conventional IR imaging or during breathold in the snapshot IR (turboFLASH) technique. Thus, the optimization of RF pulses is useful in obtaining faster IR images, increasing the contrast and/or increasing the number of imaging planes.

Abdomen↗
PubMed1992

Studies to determine the basis for hyperkalemia in recipients of a renal transplant who are treated with cyclosporine.

Hyperkalemia is commonly encountered in patients who receive a renal transplant and the immunosuppressive drug, cyclosporine. There is also a high incidence of hypertension (which is thought to be due to expansion of the extracellular fluid volume) and hyperchloremic metabolic acidosis in this group of patients. This constellation of findings led to the suspicion of the possibility that their basis might be type II hypoaldosteronism. To test this hypothesis, 12 patients with hyperkalemia (plasma K+, 5.1 +/- 0.2 mmol/L at the time of study) while receiving cyclosporine were studied. Patients who had diabetes mellitus, those receiving drugs known to cause hyperkalemia (e.g., beta blockers, angiotensin-converting enzyme inhibitors, K(+)-sparing diuretics), or those with a serum creatinine greater than 200 mumol/L were excluded. The renal response to hyperkalemia was inappropriate because the transtubular K+ concentration gradient (TTKG) was only 4.3 +/- 0.4 compared with a TTKG of 13 +/- 1, 2 h after 50 mmol of KCl was given to normal subjects. The TTKG, after administration of 200 micrograms of fludrocortisone, was still very low (5.6 +/- 0.6) in the patients compared with that of controls (12 +/- 1). After administration of 250 to 500 mg of acetazolamide to increase the delivery of bicarbonate to the distal nephron, the TTKG rose significantly to 11 +/- 1 in patients on cyclosporine, compared with 17 +/- 1 in the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetazolamide↗
PubMed1990

[Cytomegalovirus diagnosis in blood donors and risk patients].

The transfusion transmitted CMV is a possibly dangerous complication of transfusion therapy in immunodeficient patients. We therefore investigated blood donors and patients at increased risk of CMV-infection for CMV-IgG-and-IgM-antibodies. The following CMV IgG and CMV IgM prevalence rates were observed: blood donors 63.7% (0.98%), organ donors 76.9% (0%), patients on hemodialysis 83.0% (17.0%) and drug abusers 57.7% (1.3%). We conclude from our results that CMV IgG testing is useful at every blood donation to provide a large pool of CMV negative blood donors.

Antibodies, Viral↗
PubMed1990

[CMV antibody determination with two enzyme immunoassays in each case].

In each of the two present studies (Frankfurt blood donor center and blood bank of the university of Hamburg) two commercial enzyme immunoassay (EIA) test kits for detecting cytomegalovirus (CMV) antibodies were compared according to their concordance. In the Frankfurt study, 448 sera of blood donors and patients were tested for IgG- and IgM-specific antibodies by CMV-ELA Test (Medac); IgG-specific antibodies were tested in 3 serum dilutions (1:10, 1:100, 1:1000) of each sample, 221 sera were additionally assayed using the EIA of ABBOTT. Both methods showed the same results in 214/221 (96.8%) sera (p less than 0.001). The determination of CMV-IgG-specific antibody levels were as follows: Out of 294 seropositive individuals, titers greater than or equal to 1:1000 were seen in 81% (238). IgM antibodies to CMV were determined in 22/448 serum specimen, which all had IgG antibodies too; there were 18/22 (81.8%) samples with elevated titers for CMV-IgG (greater than or equal to 1:1000). In the second study, 500 sera of blood donors from Hamburg were tested for CMV-IgG antibodies by two enzyme immunoassays, CMV-IgG-ELA (Medac) and Anti-CMV-IgG-ELISA (Biotest). The results were concordant in 418 (83.6%) of the 500 samples (p less than 0.01). All EIA procedures were found to be convenient test methods for CMV antibody screening and the results showed significant correlations. Furthermore, the determination of CMV-IgG-specific antibodies seems to be sufficient for routine CMV screening in blood donor centers.

Antibodies, Viral↗
PubMed1990

[Significance of cytomegalovirus in blood donation].

The subjects of the present study are diagnostic and epidemiologic aspects in the determination of serum antibodies to cytomegalovirus in blood donors, organ donors, dialysis patients and drug addicts (some of whom were HIV-positive); antibodies were determined using the ELA-Test (CMV-IgG ELA and CMV-IgM-ELA). 221 sera were additionally assayed using the CMV total AB EIA which has been used in the Frankfurt blood center since May 1985 for CMV antibody screening of blood donors: both enzyme immunoassays showed the same results in 214 sera (96.8%), which shows a high rate of correlation (requiv = 0.99, p less than 0.001). The groups were found to be CMV antibody positive as follows: blood donors 65/102 (63.7%), organ donors 10/13 (76.9%), dialysis patients 88/106 (83.0%), drug addicts 131/227 (57.7%), and HIV-antibody-positive drug addicts 17/31 (54.8%). There was a significant statistical difference between blood donors and dialysis patients (p less than 0.01); the difference between blood donors and drug addicts was also statistically significant when age was considered (p less than 0.001). There was no statistical significance in the distinction between HIV-negative and HIV-positive drug addicts. IgM-specific antibodies were found in 1/102 (0.98%) blood donors, 18/106 (17.0%) dialysis patients and 3/227 (1.3%) drug addicts, whereas in organ donors no IgM-specific antibodies were determined. The seropositivity rate of a Frankfurt group of regular blood donors (n = 1826) was 55.5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Aminophylline toxicity.

Aminophylline therapy has undergone change in the past decade. With the changes in usage and dosage forms, the frequency of toxicity in the pediatric population, especially in adolescents, has increased dramatically. Two distinct patterns, chronic and acute, have been recognized and treatment methods for both are changing. Table 4 summarizes the emerging state-of-the-art therapy for aminophylline toxicity. Judging from the activity seen in the literature, investigation into aminophylline toxicity will continue to be a priority. We will see a greater understanding of the disease process and a refining of the therapeutic process. The ultimate goal is the elimination of mortality and the minimization of morbidity from aminophylline toxicity.

Adolescent↗
PubMed1987

Cytomegalovirus infection of the alimentary canal: radiologic findings with pathologic correlation.

A spectrum of radiologic findings in cytomegalovirus (CMV) infection of the alimentary canal seen in 14 patients and correlated with pathologic examinations is described. Twelve patients had acquired immunodeficiency syndrome and two had no identified immunosuppression. Autopsies were performed on 12. Diffuse CMV colitis was present in eight patients, enteritis in seven, esophagitis in four, gastritis in two, cholangitis in one, and acute pancreatitis in one. Of 11 patients with enteritis and/or colitis seven had significant lower gastrointestinal bleeding and five died as a result of it. Radiologic findings in the gastrointestinal tract included superficial or deep mucosal ulcerations, perforation or fistula formation, luminal narrowing, rigidity and thickening of the intestinal wall, and inflammatory infiltration of the mesentery. These were seen on barium examinations and computed tomographic (CT) scans. Findings of pancreatitis were seen on CT scans in one patient. In another, a cholangiogram showed abnormal bile ducts caused by CMV cholangitis. The radiologist should be aware of the diverse manifestations of the disease and its likely occurrence in immunosuppressed individuals.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Methods of cancer case selection: implications for research.

The race, age, and sex differences between clinically and microscopically diagnosed cancer cases for a total of 63,301 incident cases for 18 sites are reported. The cases, diagnosed during 1973-1978, were drawn from the Cancer Surveillance Section in the Division of Epidemiology at the Michigan Cancer Foundation in Detroit, a participant in the Surveillance, Epidemiology, and End Results (SEER) program. Although microscopically diagnosed cases and those diagnosed by other methods differed by race and sex for a few sites, the two case groups differed by age for 15 of the 18 sites examined. Cases without microscopic diagnoses (i.e., clinical diagnoses) tended to be older than microscopically confirmed cases. These findings indicate that in studies of certain cancer sites, the method of case selection could affect results pertaining to age differences in exposure to and effects of relevant risk factors.

Adolescent↗
PubMed1983

Effect of the dynamic response of transducer-tubing system on accuracy of direct blood pressure measurement in patients.

The dynamic responses of 3 transducer-tubing systems (TTS) were documented using square and sine wave generators. The TTS tested were P23 ID with 5 feet tubing (P23-5'), P23 ID with 6 inches tubing (P23-6") and P50A transducer with no tubing (P50). Natural frequencies were 45, 33, and 7 Hz for P50, P23-6", and P23-5', respectively. All were underdamped (damping coefficients 0.1-0.3). Simultaneous measurements of blood pressures by the 3 TTS revealed that systolic pressures recorded by P23-5' were significantly higher (p less than 0.001) than by P23-6" (17%) and P50 (16%). This difference was not influenced by the size of the arterial cannula or by the heart rate. However, the differences were greater with radial, compared to brachial arterial cannulation (p less than 0.02). There were no differences in systolic pressures measured with P23-6" and P50. There were no differences in diastolic or electronic mean pressures recorded by the 3 TTS.

Adult↗
PubMed1983

Evidence for activated peripheral blood T-cells in rheumatoid arthritis.

We have previously demonstrated defective antigen specific T-suppressor (Ts) cell function in the peripheral blood lymphocytes (PBL) from patients with rheumatoid arthritis (RA). Our study was designed to delineate whether diminished Ts activity is due to impaired interleukin (IL) dependent clonal expansion of Ts cells or to prior in vivo activation. Patients with recent onset of RA, or a disease flare, exhibited enhanced IL generation (IL-1 and /or IL-2). Increased proportions of active E-rosettes, elevated spontaneous production of IgM, and total immunoglobulin in mitogen free cultures were consistent with the concept of prior lymphocyte activation in vivo. Our results do not support defective clonal expansion of Ts cells as the basis of deficient IL generation, but do support the concept of in vivo activation of PBM cells in some patients with RA.

Adult↗