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Biomedical subjects

J Griffin

Publications and source records attributed to J Griffin.

At least 73 records · Page 4Linked to original sources
PubMed1991

Human immunodeficiency virus type 1 mutants resistant to nonnucleoside inhibitors of reverse transcriptase arise in tissue culture.

We have recently described a nonnucleoside compound that specifically inhibits the reverse transcriptase of human immunodeficiency virus type 1 (HIV-1), the causative agent of AIDS. This compound, nevirapine (BI-RG-587), interacts with highly conserved tyrosine residues at positions 181 and 188 in the reverse transcriptase to inhibit the recombinant enzyme and virus replication in cell culture with 50% inhibitory concentrations in the 40 nM range. HIV-1 variants resistant to nevirapine emerged with passage in cell culture in the presence of drug. This resistant phenotype was stable with continued passage in the absence of drug. These mutants had a substitution of cysteine for the tyrosine at position 181. Introduction of this mutation into the recombinant enzyme increased the inhibitory concentration of nevirapine 100-fold. Substitution of cysteine for tyrosine at residue 181 into the wild-type viral genome conferred a similar reduction in susceptibility to nevirapine. Mutants were also resistant to a tetrahydroimidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-one and -thione derivative and two 6-phenylthiouracil derivatives but retained their sensitivity to the other reverse transcriptase inhibitors, 3'-azido-3'-deoxythymidine and foscarnet.

Amino Acid Sequence↗
PubMed1991

Product patents.

Explore the source record for details and available documents.

Drug Industry↗
PubMed1991

Effect of dantrolene in Duchenne muscular dystrophy.

We have demonstrated that maneuvers capable of reducing Ca influx into cells have beneficial effects in dystrophic hamsters and Duchenne muscular dystrophy. Since dantrolene inhibits Ca release from the sarcoplasmic reticulum, its effects on DMD was studied in 7 patients of 6 to 13 years of age (mean 10.8 years). Patients were studied for 4 years with tri-monthly evaluations of manual muscle testing (MMT), functional activity, and serum CK and aldolase. During the first 2-year period, no medicines were given and served as control. In the second 2-year period, dantrolene 8 mg/kg/d was administered. No side effects were observed. In 1 patient, mild weakness occurred that disappeared when the dose was reduced to 6 mg/kg/d. The 95% confidence limit for the difference in slopes of regression lines from tri-monthly MMT was asymmetric in favor of dantrolene in 5 of 7 patients. Serum CK did not differ between the first and second year of the control and treatment periods, respectively. However, it fell significantly from the second year of control to the first year of treatment (P = 0.003). The fall during the first year of treatment was significantly greater (P less than 0.01) than in age-matched natural history controls during the same length of observation. There was a 3-fold reduction in CK when the pooled values of the first and second year control vs. treatment periods were analyzed. No changes were observed in functional activity and serum aldolase. The data suggest that dantrolene reduces serum CK in DMD associated with a lessening trend in MMT deterioration.

Adolescent↗
PubMed1991

A chorionic gonadotropin-secreting human pituitary cell.

Recent data from our laboratory show that hCG is secreted in a pulsatile manner in parallel with human LH (hLH) in nonpregnant normal humans. Furthermore, GnRH stimulates hCG and hLH release. Using a monoclonal antibody specific for the beta-chain of hCG and not reacting with hLH, we have identified a heretofore unknown cell type in human pituitaries which stains only for hCG. The light microscopic, immunocytochemical, and ultrastructural features are described. These data coupled to those from multiple earlier studies indicate that hCG is secreted by these cells in normal nonpregnant humans.

Chorionic Gonadotropin↗
PubMed1991

Purified preparations of human luteinizing hormone are contaminated with small amounts of a chorionic gonadotropin-like material.

We have identified a CG-like protein contaminating a purified human LH preparation of immunochemical grade. This CG-like material is estimated to comprise 0.17%, by weight, of the LH and reacts in specific, sequential-type, two-monoclonal antibody, immunoradiometric assays for CG as well as in the carboxyl-tail CG RIA. The CG-like material is not separable from LH by size exclusion or ion exchange chromatography. The LH can be freed of this small contamination of CG-like material by immunopurification employing specific monoclonal antibodies. Sephadex G-100 chromatography shows this material to have a mol wt of 40.0K. Western blot analysis of the LH run under nonreducing conditions, using an anti-CG carboxyl-tail primary antibody, reveals two bands of this CG-like material, one at 60.8K and one at 50.7K. When electrophoresed under reducing conditions, the material reacts with the anti-CG carboxyl-tail antibody at several mol wt, ranging from 10.5-64K.

Blotting, Western↗
PubMed1991

Polyneuropathy syndromes associated with serum antibodies to sulfatide and myelin-associated glycoprotein.

We studied a series of 64 patients with sensory +/- motor peripheral neuropathies by comparing clinical and physiologic features to serum antibody reactivity against compounds containing sulfated carbohydrate moieties. We determined antibody reactivity by an enzyme-linked immunosorbent assay (ELISA) using purified glycolipids and glycoproteins as antigens, and we used high-performance thin-layer chromatography and Western blotting to test the specificity of results. Twelve patients with high titers of IgM antibodies directed against the myelin-associated glycoprotein (MAG) had sensory-motor polyneuropathies with physiologic evidence of demyelination. IgM antibody reactivity to MAG was associated with an IgM serum M protein in five patients. Eight other patients, most with sensory greater than motor polyneuropathies, had high titers of antibody reactivity to sulfatide but not of IgM to MAG. Two had an associated IgM paraprotein. None of the patients with selective serum antisulfatide activity had predominantly demyelinating features on physiologic testing. We conclude that (1) high ELISA titers of antibodies to MAG may be more common than previously suspected in patients with chronic demyelinating sensory-motor neuropathies, and (2) the presence of high titers of antisulfatide antibodies in serum may provide clues to the pathogenesis of otherwise idiopathic, axonal, predominantly sensory neuropathies.

Adult↗
PubMed1991

Ultrasensitive, specific, two-antibody immunoradiometric assay that detects free alpha subunits of glycoprotein hormones in blood of nonpregnant humans.

This noncompetitive, sensitive, immunoradiometric assay of the free alpha subunit of human pituitary glycoprotein hormones is based on two monoclonal antibodies and an avidin-biotin separation system. The affinity of the first antibody, mouse anti-alpha subunit covalently conjugated to biotin, is 3.8 x 10(11) L/mol. The second antibody, radiolabeled with 125I, has an affinity of 5.4 x 10(11) L/mol. A polystyrene ball coated with avidin serves as the separation system. Tests of "purified" immunochemical-grade intact human glycoprotein hormones yielded cross-reactions of approximately 2% in the assay. Sephadex G-100 column chromatography showed that this "cross-reaction" was caused by contamination of the various hormone preparations with free alpha subunit. When the intact glycoprotein hormones were further purified with specific anti-alpha monoclonal antibody, their reaction in the alpha subunit assay was undetectable (less than 0.01%). Interassay CV averaged 3.5%, and intra-assay CV averaged 7.5% at low concentrations of subunit. The detection limit of the assay (0.01 micrograms/L) is adequate to detect free alpha subunit in the blood of normal humans. Mean (SD) concentrations of free alpha subunit in normal humans were as follows: eugonadal men = 437 (35) ng/L; postmenopausal women = 1231 (40) ng/L; eugonadal women, follicular phase = 1061 (40) ng/L; eugonadal luteal phase = 780 (45) ng/L.

Adult↗
PubMed1990

Identification of amino acids in the gamma-carboxylation recognition site on the propeptide of prothrombin.

A gamma-carboxylation recognition site on the propeptide of the vitamin K-dependent blood coagulation proteins directs the carboxylation of glutamic acid residues by binding to the vitamin K-dependent carboxylase. To determine residues that define this site, we evaluated the effect of mutation of certain residues in the prothrombin propeptide on the extent of carboxylation. The prothrombin cDNA modified by site-specific mutagenesis was expressed in Chinese hamster ovary cells using a system that yields functional fully carboxylated prothrombin. The cell supernatants containing recombinant prothrombin were evaluated for the extent of gamma-carboxylation by immunoassay. Conformation-specific anti-prothrombin:Ca(II)-specific antibodies measure native completely carboxylated prothrombin; anti-prothrombin:total antibodies measure all forms of prothrombin, regardless of gamma-carboxyglutamic acid content. Mutation of His-18 to Gly, Val-17 to Ser, Leu-15 to Gly or Asp, or Ala-10 to Asp was associated with a partial (30-65%) inhibition of gamma-carboxylation. Mutation of Ala-14 to Ser or Ser-8 to Val did not inhibit gamma-carboxylation. From this and earlier work, residues whose mutation leads to a significant impairment of carboxylation include His-18, Val-17, Phe-16, Leu-15, and Ala-10. Residues whose mutation does not alter the carboxylation recognition site include Ala-14, Ser-8, Arg-4, and Arg-1. To determine the size of the recognition site, the in vitro carboxylation of propeptide-containing synthetic peptides was compared. A 28-residue peptide, based upon residues -18 to +10 of prothrombin, and a 54-residue peptide, based upon residues -18 to +36 of prothrombin, were carboxylated by partially purified bovine carboxylase with similar Km values of 2-5 microM. These results indicate that the gamma-carboxyglutamic acid-rich region of prothrombin makes a minimal contribution to carboxylase binding. A molecular surface of about five amino acids located within the propeptide appears to define the carboxylation recognition site on the precursor forms of the vitamin K-dependent proteins.

Amino Acid Sequence↗
PubMed1990

Structure of the gene encoding the human leukocyte adhesion molecule-1 (TQ1, Leu-8) of lymphocytes and neutrophils.

The leukocyte adhesion molecule-1 (LAM-1, TQ1, Leu-8), expressed by human lymphocytes, neutrophils, monocytes, and their precursors, is a member of the selectin family of cellular adhesion/homing receptors which play important roles in leukocyte-endothelial cell interactions. These cell surface molecules contain an amino-terminal lectin-like domain followed by an epidermal growth factor-like domain and a variable number of short consensus repeat sequences similar to those found in C3/C4 binding proteins. In this report, the structure of the lyam-1 gene that encodes the LAM-1 protein was determined by isolating overlapping genomic DNA clones that hybridized with a LAM-1 cDNA probe. The lyam-1 gene spans greater than 30 kilo base pairs of DNA and is composed of at least 10 exons. The 5' end of the LAM-1 mRNA was mapped by primer extension analysis revealing a single initiation region for transcription. Exons II through X contain translated sequences; exon II encodes the translation initiation codon; exon III, the leader peptide; IV, the lectin-like domain; V, the epidermal growth factor-like domain; VI and VII, the short consensus repeat units; exon VIII, the transmembrane region; exon IX encodes seven amino acids containing a potential phosphorylation site; and exon X encodes the five remaining amino acids of the cytoplasmic tail and the long 3' untranslated region. Sequencing of LAM-1 cDNA clones derived from neutrophils revealed that the protein expressed by neutrophils would be identical in sequence with the protein expressed by lymphocytes and cDNAs that would encode different isoforms of LAM-1 protein were not detected. In addition, the level of LAM-1 expression by lymphocytes and neutrophils from two patients with paroxysmal nocturnal hemoglobinuria, a disorder in which linkage of phosphatidylinositol anchors to proteins is defective, was similar to that of normal controls. Therefore, the usage of exons II through X results in the generation of a single major LAM-1 protein product expressed by lymphocytes and neutrophils.

Base Sequence↗
PubMed1990

Nutrient intakes during pregnancy: observations on the influence of smoking and social class.

The influence of smoking and social class on dietary intake in pregnancy was investigated in a random sample of smokers (greater than or equal to 15 cigarettes/d) and nonsmokers. A total of 206 subjects (94 smokers and 112 nonsmokers) completed a 7-d weighed dietary intake at 28 wk gestation and 178 completed a second assessment at 36 wk. Nonsmokers had higher intakes of almost all nutrients than did smokers and the nutrient density of their diet was greater. Energy intake was nonsignificantly higher in nonsmokers. Women in higher social classes had the highest nutrient intakes. Smokers were shorter than nonsmokers and tended to be of lower social class. After maternal height and social class were controlled for, smoking had a significant effect on intake of many micronutrients. Dietary intake was reduced in late pregnancy, particularly in smokers. These data suggest that smokers in all social classes have a poorer quality of diet.

Adult↗
PubMed1990

Developing a test of knowledge of surgical options for breast cancer.

Because many women now have a choice regarding the type of surgery they prefer for early stage breast cancer, it is important for clinicians to provide comprehensive information about these options and to determine whether patients have understood this information. The purpose of this study was to develop a short, easily administered, valid and reliable test of women's knowledge of surgical treatment options for early stage breast cancer. Instrument development was carried out in two phases: (a) content domains were established and items were generated and examined for content validity and clarity; and (b) the known-groups technique was used to determine construct validity and to generate data for reliability testing. The test was administered to 44 student nurses, 21 women with breast cancer, and 24 practicing nurses. An 18-item test--the BCIT-R (Breast Cancer Information Test-Revised)--with modest internal consistency and very good construct validity resulted from these steps. Nurses scored significantly better than either students or patients. The instrument is discussed in terms of psychometric issues and clinical use.

Adult↗
PubMed1990

Secretion of chorionic gonadotropin by cultured human pituitary cells.

To investigate the possibility that the human pituitary gland secretes CG, we used a highly specific, two-site, double monoclonal immunoradiometric assay to measure CG in the medium in which the dispersed cells of pituitary glands from human fetuses of 20-24 weeks gestation were cultured. The cross-reactivity of immunopurified human LH in the CG assay was less than 0.03%. LH was also measured by a double monoclonal immunoradiometric assay. Secretion of CG by the cultured fetal pituitary cells was readily detectable, although in gradually decreasing amounts, for the 11 days of culture. LH secretion paralleled CG secretion and was much greater in magnitude. Pituitary cells from female fetuses generally secreted more CG as well as more LH than those from male fetuses. Dilutions of the medium showed that the secreted CG exhibited parallelism with the CG standard. Chromatofocusing of the medium across a pH 6-9 gradient yielded several peaks of LH immunoreactivity between pH 6.5 and 8.5, but no peaks of CG. Chromatofocusing of the medium across a pH 3-7 gradient yielded peaks of CG, but not LH, between pH 4.0-5.5. These data indicate that CG immunoreactivity, distinct and separable from LH immunoreactivity, is secreted by the dispersed cells of fetal human pituitary glands.

Antibodies, Monoclonal↗