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Biomedical subjects

A Glassman

Publications and source records attributed to A Glassman.

36 records · Page 2Linked to original sources
PubMed1996

Differential expression of lacZ in the liver and kidney of transgenic mice carrying chimeric lacZ-erythropoietin gene constructs with or without its 1.2 kb 3'-flanking sequence.

Erythropoietin (EPO) plays a key role in erythropoiesis and is expressed predominantly in the fetal liver and in the adult kidney. The EPO gene is up-regulated at the transcriptional level under hypoxic/anemic conditions. We studied the role of the 5'- and 3'-flanking sequences of the mouse EPO gene in its tissue-specific and hypoxia-induced expression by developing transgenic mouse lines carrying chimeric EPO-lacZ gene constructs. Transgenic mice carrying a 6.5 kb segment of the 5'-sequence and most of the EPO gene in which lacZ was substituted for exon 1 (5'-lacZ-EPO) demonstrated induction of lacZ expression following hypoxia/ anemia induction in both the liver and kidney of adult mice. However, transgenic mice carrying the above construct along with the 1.2 kb 3'-flanking sequence (5'-lacZ-EPO-3') showed a high level of lacZ expression following hypoxia/anemia induction in adult kidney but not in adult liver. With the aim of further understanding the role of the 3'-flanking sequence in tissue-specific expression of the EPO gene, we studied the interactions of protein factors with this 1.2 kb 3' region and demonstrated that multiple sets of protein factors interact tissue specifically with a 10 bp sequence, TCAAAGATGG, located downstream of the previously characterized 3' hypoxia-responsive enhancer element.

Animals↗
PubMed1996

Abnormal expression of MDM-2 in breast carcinomas.

MDM-2 is a cellular oncoprotein that binds to the p53 protein and abrogates its growth-suppressing function. At least seven MDM-2 mRNAs and five proteins (p90, p85, p76, p74, and p57) have been reported in tissue culture. MDM-2 gene amplification occurs in human sarcomas and high-grade gliomas. MDM-2 overexpression without gene amplification has been reported in leukemias and lymphomas. Here we report MDM-2 mRNA overexpression in 24 (73%) out of 33 cases of human breast carcinoma as compared with normal breast tissue. The MDM-2 overexpression was seen in the absence of MDM-2 gene amplification. MDM-2 protein expression was studied by western blot analysis in 21 of these cases of carcinoma. We found complete concordance between MDM-2 mRNA overexpression and MDM-2 protein levels. MDM-2 proteins were overexpressed in 15 of 21 breast carcinoma tissue samples but not in normal breast tissue controls. Ten of these fifteen cases overexpressed MDM-2 p57 protein, two cases overexpressed both p57 and p90, and three cases overexpressed only p90. MDM-2 overexpression was confirmed by immunohistochemistry. p53 overexpression was also studied by immunohistochemistry, 69% of breast carcinomas that overexpressed the MDM-2 mRNA had detectable nuclear p53 protein. These findings demonstrate that MDM-2 oncoprotein expression is altered in primary human breast carcinomas at both mRNA and protein levels. In addition, our results suggest that MDM-2 p57 protein represents the main MDM-2 protein altered in breast carcinomas.

Blotting, Western↗
PubMed1996

Comparison of bcr-abl protein expression and Philadelphia chromosome analyses in chronic myelogenous leukemia patients.

The Philadelphia chromosome (Ph) is found in most chronic myelogenous leukemia (CML) patients. The bcr-abl oncoprotein (P210 or P185), the product of the fused bcr-abl gene produced by the Ph, is known to be the major factor in initiation and maintenance of the leukemic state in these types of leukemias. The authors have devised a Western blot test to detect and quantitate the bcr-abl oncoprotein in blood and bone marrow cells. The authors analyzed 1,155 peripheral blood samples from CML patients, for which there were same day Ph data, to determine if there was a correlation between bcr-abl protein levels and the percentage of Ph. A ratio of bcr-abl protein (P210 or P185) to normal abl protein (P145), the latter is ubiquitously expressed in all blood cells, has been established as a criterion for quantitating bcr-abl levels. The bcr-abl/abl protein ratio from 399 patient who were 100% Ph-positive had a mean of 2.47 (standard error [SE] of +/- 0.05); no false negatives were detected. A decreasing ratio was found in patients with decreasing percentages of Ph. The relationship between the ratio of bcr-abl/abl proteins to the percentage of Ph-positive cells was nearly linear in 392 patients with Ph percentages between 5% to 95% (r = 0.97, P < .001). For patients in remission with no detectable Ph, the bcr-abl/abl ratio had a mean of 0.01 (SE = 0 +/- 0.00). The level of bcr-abl expression in samples from peripheral blood and bone marrow also were compared. The results indicated that the amount of bcr-abl protein within peripheral blood is usually similar to that in marrow. In conclusion, quantitation of the bcr-abl oncoprotein in peripheral blood cells or marrow cells as measured by a Western blot assay provides reliable data for both diagnosis and monitoring patients with pH-chromosome positive leukemia.

Blotting, Western↗
PubMed1995

p16INK4A and p15INK4B gene deletions in primary leukemias.

The 9p21 locus has been deleted at a high frequency in a wide variety of tumors. Recently, two genes, p16INK4A and p15INK4B (also called MTS1 and MTS2), have been localized in close proximity at the 9p21 locus, encoding cyclin-dependent kinases 4/6 inhibitors of relative molecular mass 16 kD and 15 kD, respectively and also found to be deleted at a high frequency in tumor cell lines. We analyzed p16INK4A and p15INK4B genes in 178 cases of primary leukemias including 81 cases of chronic lymphocytic leukemia (CLL), seven of hairy cell leukemia (HCL), seven of chronic myelogenous leukemia (CML), 43 of acute myelogenous leukemia (AML), 27 of acute lymphoblastic leukemia (ALL), and 13 of myelodysplastic syndrome (MDS) by Southern blot analyses. The ALL cases showed a relatively high frequency of homozygous deletions (22%, 6 of 27) at the p16INK4A gene locus. Interestingly, of the six cases with p16INK4A homozygous deletions, only three showed homozygous deletions at the p15INK4B gene. In 81 CLL patients, we detected one homozygous and five heterozygous deletions at both the p16INK4A and p15INK4B genes and two heterozygous deletions at the p16INK4A gene alone. Deletion of these two genes in AML cases is relatively low (9%). We did not detect deletions in any of the MDS, HCL, and CML cases examined. Sequence analyses of p16INK4A gene of six CLL cases with heterozygous deletion at this locus showed a 27-bp deletion at the splice acceptor site of intron 1 in one case and changes in the coding sequence in three other cases. The data presented in this report showed that (1) p16INK4A and p15INK4B genes are preferentially deleted homozygously in ALL and heterozygously in CLL cases with frequent mutation in the second allele, and (2) p16INK4A gene appears to be more frequently deleted than p15INK4B gene.

Base Sequence↗
PubMed1993

Depressed affect, hopelessness, and the risk of ischemic heart disease in a cohort of U.S. adults.

Major depression has been associated with mortality from ischemic heart disease (IHD). In addition, a symptom of depression--hopelessness--has been suggested as a determinant of health status. We studied the relation of both depressed affect and hopelessness to IHD incidence using data from a cohort of 2,832 U.S. adults age 45-77 years who participated in the National Health Examination Follow-up Study (mean follow-up = 12.4 years) and had no history of IHD or serious illness at baseline. We used the depression subscale of the General Well-Being Schedule to define depressed affect and a single item from the scale to define hopelessness. At baseline, 11.1% of the cohort had depressed affect; 10.8% reported moderate hopelessness, and 2.9% reported severe hopelessness. Depressed affect and hopelessness were more common among women, blacks, and persons who were less educated, unmarried, smokers, or physically inactive. There were 189 cases of fatal IHD during the follow-up period. After we adjusted for demographic and risk factors, depressed affect was related to fatal IHD [relative risk = 1.5; 95% confidence interval (CI) = 1.0-2.3]; the relative risks of fatal IHD for moderate and severe levels of hopelessness were 1.6 (95% CI = 1.0-2.5) and 2.1 (95% CI = 1.1-3.9), respectively. Depressed affect and hopelessness were also associated with an increased risk of nonfatal IHD. These data indicate that depressed affect and hopelessness may play a causal role in the occurrence of both fatal and nonfatal IHD.

Aged↗
PubMed1984

Determination of bupropion and its major basic metabolites in plasma by liquid chromatography with dual-wavelength ultraviolet detection.

A method for the determination of bupropion and its three major basic metabolites in plasma is described. Following an extraction from alkaline plasma into 1.5% v/v isoamyl alcohol in n-heptane, a portion of the acid-backwashed extract was injected onto a column packed with trimethylsilyl reverse-phase material and eluted with a phosphate buffer-acetonitrile (80:20) mobile phase containing an ion-pairing reagent and triethylamine. The compounds were detected with a dual-wavelength UV detector (214 and 254 nm) to optimize sensitivity and facilitate simultaneous detection. The method provides an absolute recovery of approximately 85% for bupropion and approximately 98% for the metabolites. Day-to-day reproducibility did not exceed 4.0% for all compounds. The detection limits were approximately 5 ng/mL for bupropion and 100 ng/mL for the major metabolites. The limit of 100 ng/mL for metabolite quantitation is imposed by the internal standard concentration selected for steady-state studies. In single-dose pharmacokinetic studies, 10% of the steady-state concentration of internal standard was used; this permitted a 10-ng/mL lower limit of detection. Steady-state plasma levels of bupropion and the metabolites from eight different patients are presented.

Bupropion↗
PubMed1983

Phosphorylation of brain synaptic and coated vesicle proteins by endogenous Ca2+/calmodulin- and cAMP-dependent protein kinases.

Phosphorylation of brain synaptic and coated vesicle proteins was stimulated by Ca2+ and calmodulin. As determined by 5-15% sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis (PAGE), molecular weights (Mr) of the major phosphorylated proteins were 55,000 and 53,000 in synaptic vesicles and 175,000 and 55,000 in coated vesicles. In synaptic vesicles, phosphorylation was inhibited by affinity-purified antibodies raised against a 30,000 Mr protein doublet endogenous to synaptic and coated vesicles. When this doublet, along with clathrin, was extracted from coated vesicles, phosphorylation did not take place, implying that the protein doublet may be closely associated with Ca2+/calmodulin-dependent protein kinase. Affinity-purified antibodies, raised against clathrin used as a control antibody, failed to inhibit Ca2+/calmodulin-dependent phosphorylation in either synaptic or coated vesicles. Immunoelectron cytochemistry revealed that this protein doublet was present in axon terminal synaptic and coated vesicles. Synaptic vesicles also displayed cAMP-dependent kinase activity; coated vesicles did not. The molecular weights of phosphorylated synaptic vesicle proteins in the presence of Mg2+ and cAMP were: 175,000, 100,000, 80,000, 57,000, 55,000, 53,000, 40,000, and 30,000. Based on the different phosphorylation patterns observed in synaptic and coated vesicles, we propose that brain vesicle protein kinase activities may be involved in the regulation of exocytosis and in retrieval of synaptic membrane in presynaptic axon terminals.

Animals↗
PubMed1982

Use of a medical-grade silicone adhesive as a denture liner in the treatment of idiopathic oral mucosal irritation.

The results of the survey confirmed the clinical observation that soft liners were the best course of treatment in specifically selected patients. Most patients were satisfied with the appearance of the denture, and the length of time the patient could wear the soft-lined prosthesis increased considerably. The silicone liner also reduced irritation and increased the ability to chew food, with the patient's ability to taste food remaining essentially unaffected. The maintenance of cleanliness of the silicone, which had been a problem in the past, seemed to be markedly reduced. Above all, the enthusiastic patient acceptance of the product indicates that adhesive type A may be an excellent alternative to hard acrylic resin denture liners when a change of material is necessary.

Adhesives↗
PubMed1981

Studies on the toxicity and binding kinetics of abrin in normal and Epstein Barr virus-transformed lymphocyte culture-I: experimental results - 1.

The effects of treatment with varying doses of abrin, a D-galactose binding lectin, on DNA and protein synthesis of normal and Epstein Barr virus-transformed lymphocytes have been investigated. Activation, stimulation and relative toxicity factor indices are studied as well as possible relationships between the DNA and protein synthesis rates, as measured by simultaneous 3H-TdR and 14C-leucine uptake.

Abrin↗
PubMed1981

Studies on toxicity and binding kinetics of abrin in normal and Epstein Barr virus-transformed lymphocyte culture-I: experimental results - 2.

The effects of treatment with varying doses of abrin, a D-galactose binding lectin, on DNA and protein synthesis of normal and Epstein Barr virus-transformed lymphocytes have been investigated. Studies of activation and stimulation indices, as well as two new indices; the metabolic self and cross-coupling indices, lead to the prediction that there are three morphologically distinct subpopulations of EBV-transformed lymphocytes with different abrin binding site numbers. This conclusion is supported by SEM morphological differences.

Abrin↗
PubMed1981

Studies on the toxicity and binding kinetics of abrin in normal and Epstein Barr virus-transformed lymphocyte culture-I: experimental results - 3.

The effects of treatment with varying doses of abrin, a D-galactose binding lectin, on DNA and protein synthesis of normal and Epstein Barr virus-transformed lymphocytes have been investigated. Using data on EBV-transformed lymphocyte cell density as a function of time and dose of abrin, one can demonstrate that the mean number of sites bound/EBV-lymphocyte needed to exert a biological influence upon the cell DNA synthesis lies between 59,264 and 370,000 sites/cell. Using a simple packing model, one can demonstrate that a theoretical estimate places the number of binding sites between 57,600 and 360,000 sites/cells.

Abrin↗
PubMed1975

Human growth hormone response to levodopa. Relation to menopause, depression, and plasma dopa concentration.

After ingestion of 500 mg of levodopa, postmenopausal women had significantly diminished human growth hormone (HGH) responses (mean, 4.6 ng/ml), as compared with those of age-matched men (mean, 9.1 ng/ml; P smaller than .05). The differences between the groups were not related to plasma dopa concentrations. The HGH responses to levodopa of age-matched unipolar and bipolar depressed men, and of unipolar depressed postmenopausal women, did not differ significantly from their respective normal control groups. Depressive illness of these types does not appear to affect the HGH response to levodopa, once the effect of the menopause is taken into account.

Adult↗
PubMedDate not supplied

Euglobulin lysis times: an update.

UNLABELLED: There are several clot lysis tests available to assess the presence of increased fibrinolysis in a clinical situation. These include whole blood, plasma, and "eugloblin" lysis tests. The euglobulin lysis test (ELT) is actually a modified plasma clot lysis time, which detects increased plasminogen activation and subsequent fibrinolysis. It does not detect the activity of antiplasmins. The purpose of this study was to determine ELT for a group of 25 ambulatory normals. There were 10 males and 15 females, ranging in age from 25 to 56 years. Citrate anticoagulated samples were obtained immediately after application of a tourniquet and 10 minutes after application of a sphygmomanometer inflated to midway between systolic and diastolic pressure. The citrated plasma was precipitated with cold acetic acid. The precipitate contained fibrinogen, plasminogen, and plasminogen activators, with fibrinolytic inhibitors theoretically removed. The precipitate was redissolved and the euglobulin solution was clotted with thrombin. The clotted sample was then incubated at 37 degrees C and was observed at 10 minute intervals for clot lysis. RESULTS: The reference range of onset of fibrinolysis was from 1.25 to 12 hours, with a mean of 3.78 hours +/- 2.45 hours (1 S.D.). Venostasis (use of the sphygmomanometer) resulted in an ELT that was shorter than the non-venostasis specimens in 11 of 25 specimens. This is thought to be secondary to in vivo activation of plasminogen. CONCLUSION: The average euglobulin lysis time in 25 ambulatory normals is approximately 3.5 hours. The ELTs vary over a broad range (1.25 to 12.0 hours) in normal ambulatory volunteers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗