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Biomedical subjects

J Rose

Publications and source records attributed to J Rose.

At least 145 records · Page 8Linked to original sources
PubMed1992

Tethered ligand agonist peptides. Structural requirements for thrombin receptor activation reveal mechanism of proteolytic unmasking of agonist function.

The human platelet thrombin receptor is activated when thrombin cleaves its receptor's amino-terminal extension to reveal a new amino terminus that functions as a tethered peptide ligand. Exactly how this "agonist peptide domain" remains cryptic within the uncleaved receptor and becomes functional after receptor cleavage is unknown. In this report we define the structural features of the thrombin receptor's agonist peptide domain important for receptor activation. Studies with mutant thrombin receptors have suggested that agonist peptide domain residues 2-6 contained determinants critical for receptor activation, and the synthetic peptide SFLLR-NH2 representing the 1st 5 amino-terminal residues of the agonist peptide domain was sufficient to specify agonist activity. Acetylating or removing the agonist peptide's amino-terminal ammonium group greatly attenuated agonist activity. Agonist peptide residue Phe2 was vital for agonist function; residues Leu4 and Arg5 individually played less important roles. These structure-function relationships held for both platelet activation and activation of the cloned receptor expressed in transfected mammalian cells. Our studies suggest that structures at the extreme amino terminus of the thrombin receptor's agonist peptide domain, in particular the free ammonium group of Ser1 and the phenyl ring of Phe2, are critical for receptor activation and that the agonist function of this domain is expressed when receptor proteolysis unmasks such determinants. In addition to revealing details of the thrombin receptor's proteolytic triggering mechanism, these studies open avenues to the development of drugs targeting the thrombin receptor and to further definition for the role of the thrombin receptor in cellular regulation.

Amino Acid Sequence↗
PubMed1992

The role of the adrenal glands in regulating onset of winter fur growth in mink (Mustela vison).

The role of the adrenal glands in regulating onset of winter fur growth in mink was investigated in long-term adrenalectomized animals. Bilateral adrenalectomy of adult female standard dark mink between June 23 and July 11, 1990, initiated onset of winter fur growth approximately 6 weeks earlier than controls. One month following completion of the winter fur growth in adrenalectomized mink, molting and growth of a new coat was observed. The type of pelage that grew as a result of the second growth wave was less dense than the normal summer or winter fur. However, this renewed hair growth suggests that adrenal hormones not only inhibit the onset of winter fur growth but also influence the duration of inactivity following each period of hair growth. Administration of deoxycorticosterone as a mineralocorticoid supplement had no effect on initiation of fur growth. It would appear that adrenal hormones are part of the mechanism through which photoperiod regulates fur growth in the mink. The identity of the adrenal hormones and their site of action is unknown.

Adrenal Glands↗
PubMed1992

Intrarectal challenge of macaques vaccinated with formalin-inactivated simian immunodeficiency virus.

Macaques can be protected from intravenous infection with simian immunodeficiency virus (SIV) by vaccination with chemically inactivated virus. However, protection against infection via a mucosal surface has not been demonstrated. We vaccinated four rhesus macaques with formalin-inactivated SIV given intramuscularly. These monkeys, which had remained virus free for 10 months after intravenous challenge with SIV, were given a further dose of vaccine and together with four unvaccinated controls were challenged intrarectally with SIV. Subsequently, virus was isolated from all control animals on five successive occasions, but the vaccinated animals remained free of virus. Proviral DNA could not be detected in peripheral blood mononuclear cells from the vaccinated animals. Preliminary data indicate that vaccinated animals make a local antibody response.

AIDS Vaccines↗
PubMed1992

Reactive sites of an anticarcinogenic Bowman-Birk proteinase inhibitor are similar to other trypsin inhibitors.

The three-dimensional structure of the Bowman-Birk type proteinase inhibitor (PI-II) has been determined by x-ray crystallography and refined at 2.5-A resolution. This protein is a specific inhibitor of trypsin. Two reactive site loops, one at each end of the PI-II molecule, are structurally similar to each other and to reactive-site loops of pancreatic secretory trypsin inhibitor (Bolognesi, M., Gatti, G., Menegatti, E., Guarneri, M., Marquart, M., Papamokos, E., and Huber, R. (1982) J. Mol. Biol. 162, 839-869) and bovine pancreatic trypsin inhibitor (Deisenhofer, J., and Steigemann, W. (1975) Acta Crystallogr. B31, 238-250). PI-II is the first reported Bowman-Birk type inhibitor structure to be refined at high resolution, providing further insight into inhibitor mechanisms.

Amino Acid Sequence↗
PubMed1992

New-generation RIBA hepatitis C strip immunoblot assays.

Second-generation hepatitis C virus (HCV) ELISAs are currently in use in Europe and have been submitted for approval in the United States. These new assays contain additional antigens from the putative nucleocapsid and NS-3 regions of the HCV genome in addition to the c100-3 antigen present in first-generation ELISAs. A supplementary test, the second-generation RIBA HCV strip immunoblot assay (2-RIBA HCV SIA) has also been developed. The strip immunoblot assay uses four recombinant HCV antigens [5-1-1 (NS-4), c100-3 (NS-4), c33c (NS-3), and c22-3 (NS-3) (nucleocapsid)] slot blotted on nitrocellulose. Screening of random volunteer blood donors with the Ortho second-generation HCV ELISA (ORTHO HCV 2.0 ELISA) indicates that a substantial change in the repeat reactive donor population is observed with the new test. Two notable features of this change are: (1) A large number of samples reactive in the 2-RIBA HCV SIA for the second-generation antigens, c33c and c22-3, are detected by the ORTHO HCV 2.0 ELISA; (2) the percentage of ORTHO HCV 2.0 ELISA reactive specimens found indeterminate (reactive for only one HCV antigen) by the 2-RIBA HCV SIA is higher than in first-generation HCV ELISAs (approximately 25 vs. 5%). In addition, ORTHO HCV 2.0 ELISA repeat reactive, 2-RIBA HCV SIA indeterminate samples are dominated by reactivity to c22-3 instead of c100-3, which is the case for first-generation HCV ELISA repeat reactive samples. Resolution of 2-RIBA HCV SIA indeterminate samples as either containing anti-HCV antibodies or not, is important in both diagnostic and blood screening environments, especially where donor notification is required. Our approach to resolution of these troublesome samples evolved from initial work with HCV peptides. Early studies with an experimental strip immunoblot assay containing 5 peptides from the nucleocapsid, E2 (NS-1), NS-4, and NS-5 regions of the viral genome indicated that peptides from the nucleocapsid and NS-4 regions of the genome could provide additional evidence for the presence of anti-HCV antibodies with good specificity, but other peptides suffered from poor specificity. In addition, no immunoreactive peptide from the NS-3 (c33c) region of the virus is available, presumably because the major epitope(s) of this key second-generation antigen is a conformational determinant.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood Transfusion↗
PubMed1992

New generation RIBA hepatitis C strip immunoblot assays.

Second generation hepatitis C virus (HCV) Elisas are currently in use in Europe and have been submitted for approval in the United States. These new assays contain additional antigens from the putative nucleocapsid and NS-3 regions of the HCV genome in addition to the c100-3 antigen present in first generation Elisas. A supplementary test, the second generation RIBA (Chiron Co trademark) HCV strip immunoblot assay (2-RIBA HCV SIA) has also been developed. The strip immuno-blot assay uses four recombinant HCV antigens (5-1-1 [NS-4], c100-3 [NS-4], c33c [NS-3], and c22-3 [NS-3 [nucleocapsid]) slot blotted on nitrocellulose. Screening of random volunteer blood donors with the Ortho (Ortho Diagnostic Systems trademark) second generation HCV Elisa (2-Ortho HCV Elisa) indicates that a substantial change in the repeat reactive donor population is observed with the new test. Two notable features of this change are: i) a large number of samples reactive in the 2-RIBA HCV SIA for the second generation antigens, c33c and c22-3, are detected by the 2-Ortho HCV Elisa; ii) the percentage of 2-Ortho HCV Elisa reactive specimens found indeterminate (reactive for only one HCV antigen) by the 2-RIBA HCV SIA is higher than in first generation HCV Elisas (approximately 25 versus 5%). In addition, 2-ortho HCV Elisa repeat reactive, 2-RIBA HCV SIA indeterminate samples are dominated by reactivity to c22-3 instead of c100-3 which is the case for first generation HCV Elisa repeat reactive samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Lack of ras mutations and prediction of long-term survival in carcinoma of the colon.

Ras oncogene mutations are found in a significant number of human colonic carcinomas. Correlation between patient survival and ras mutations was explored and compared with other clinical parameters. Colonic carcinoma embedded in paraffin was subjected to the polymerase chain reaction using primers to amplify codon 12 of the K-ras oncogene. Oligonucleotide probes to six mutations were used to identify mutated genes. A total of 71 cases were successfully amplified. Some 54% of the cases had mutations. There was no correlation between presence of a mutation and age. Patients in Stage D, patients with a family history of carcinoma, and males have a greater incidence of ras mutations. Patients in Stage C had a lower incidence of mutations. Presence of the mutation did not correlate with decreased survival except in Stage D. Some 61% of long-term survivors with colon carcinoma living for more than 6 yr had ras mutations. The absence of K-ras mutations did not identify long-term survivors.

Adult↗
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

Crystals of a bovine neurophysin II tripeptide complex.

A bovine neurophysin II S-methyl-Cys-Tyr-Phe-NH2 complex has been crystallized using ammonium sulfate as the precipitating agent. The crystals are orthorhombic, the space group is either I222 or I2(1)2(1)2(1) with a = 124.9 A, b = 69.6 A and c = 151.5 A. The crystals diffract to at least 3.0 A resolution. Based on one neurophysin tetramer per asymmetric unit, the Matthews coefficient is calculated to be 3.92 with a solvent content of 69%.

Amino Acid Sequence↗
PubMed1991

Crystals of isoenzyme 3-3 of rat liver glutathione S-transferase with and without inhibitor.

The isoenzyme 3-3 of rat liver glutathione S-transferase (GST 3-3) isolated from a baculovirus expression system has been crystallized with and without inhibitor. The crystals grown in the absence of an inhibitor belong to space group P2(1) with cell dimensions a = 119.7, b = 96.2, c = 136.7 A and beta = 103.3 degrees, and diffract to 3 A resolution. The crystals grown in the presence of an inhibitor belong to space group C2 with cell dimensions a = 88.3, b = 69.7, c = 81.4 A and beta = 105.3 degrees, and diffract to at least 2.5 A resolution. The inhibitor used is either methylmercury chloride or ethylmercury chloride; both are weak inhibitors.

Animals↗
PubMed1991

Preliminary crystallographic analysis of cardiotoxin V with major fusion activity from Taiwan cobra (Naja naja atra) venom.

Crystals of a cardiotoxin from Taiwan cobra venom have been obtained by the vapor diffusion method using methyl pentanediol as precipitant. The crystals belong to the hexagonal space group P6(1)22 (or P6(5)22), with cell dimensions a = b = 47.5 A, c = 111.3 A, alpha = beta = 90 degrees and gamma = 120 degrees and diffract to a resolution of 2.2 A. There is one molecule per asymmetric unit and the solvent content is estimated to be 53%.

Cobra Cardiotoxin Proteins↗
PubMed1991

A fast unbiased comparison of protein structures by means of the Needleman-Wunsch algorithm.

A fast dynamic programming algorithm for the spatial superposition of protein structure without prior knowledge of an initial alignment has been developed. The program was applied to serine proteases, hemoglobins, cytochromes C, small copper-binding proteins, and lysozymes. In most cases the existing structural homology could be detected in a completely unbiased way. The results of the method presented are in general agreement with other studies. Applying our method, the different alignment results obtained by other authors for serine proteases and cytochromes C can be classified in terms of different alignment parameters such as gap penalties or cut-off length. Limitations of the method are discussed.

Algorithms↗
PubMed1991

Effects of varying marijuana smoking profile on deposition of tar and absorption of CO and delta-9-THC.

We investigated the effects of previously observed differences in smoking technique for marijuana (M) versus tobacco (T) on the amount of inhaled tar, the percentage retention of inhaled tar in the lung, the pre- to postcigarette boost in blood carboxyhemoglobin (COHb) and in serum delta-9-tetrahydrocannabinol (THC concentrations), and psychophysiologic responses to THC (increased heart rate and subjective "high"). Ten healthy, habitual smokers of M were studied on 6 separate days. On each day, subjects smoked a single M cigarette (approximately 900 mg, 1.24% delta-9-THC) using one of 6 different smoking profiles typical for marijuana [puff volume (PV) approximately 70 ml; breathholding time, (BHT) 14-16 s] or tobacco (PV approximately 45 ml; BHT 4-5 s) or a combination of the two techniques (PV approximately 70 ml and BHT 4-5 s; or PV approximately 45 ml and BHT 14-16 s). Inhaled volume (1.5 liters), interpuff interval (30 s) and number of puffs (6) were all fixed, except that for the approximately 45-ml PV condition, the number of puffs was increased to 10 in 2 additional sessions to standardize the total amount of cigarette consumed to that of the approximately 70-ml PV condition. The longer BHT significantly increased both percent retention of tar in the lung and the pre- to postsmoking rise in blood COHb, serum THC and heart rate, independent of puff volume and number. In contrast, the larger PV had no significant influence on these variables for the same amount of cigarette consumed.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1991

Tar, CO and delta 9THC delivery from the 1st and 2nd halves of a marijuana cigarette.

Previous in vitro studies suggest that, with successive puffs from a marijuana cigarette, delta-9-THC becomes concentrated in the remaining uncombusted portion of the cigarette. These observations are consistent with the common practice of smoking marijuana cigarettes to a smaller butt length than that to which tobacco cigarettes are smoked. The purpose of the present study was to compare the delivery of delta-9-THC, as well as total insoluble smoke particulates (tar) and carbon monoxide, from the distal ("first") versus the proximal ("second") halves of a standard marijuana cigarette during "natural" smoking of marijuana. On 4 separate days, ten habitual marijuana users smoked nearly all or approximately 1/2 of a standard marijuana cigarette (83 mm length; 800-900 mg; 1.24% THC), as follows: day 1, "whole" cigarette (60 mm smoked, leaving a 23-mm butt); day 2, "first" half (first 30 mm); day 3, "second" half (second 30 mm) after the "first" half was presmoked with a syringe; and day 4, "second" half after the "first" half was excised. A previously described smoking apparatus (20) was used for measurement of puff volume and inhaled tar. Puff volume and number were allowed to vary spontaneously (provided that the specified length of cigarette was consumed), while inhaled volume (1.5 liters), breathholding time (14 s) and interpuff interval (30 s) were held constant. Blood samples were withdrawn prior to smoking and serially after completion of smoking for analysis of blood carboxyhemoglobin (COHb) and serum delta-9-THC. Heart rate was measured before and 5 min after smoking. Subjects rated their level of "high" 20 min after completion of smoking.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Monoxide↗