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Biomedical subjects

J M Rose

Publications and source records attributed to J M Rose.

At least 19 recordsLinked to original sources

Beliefs about smoking cessation among out-of-school youth.

Although the majority of adolescents in the 13-18 age range are at school, there is a need to target specific groups of young smokers such as unemployed youth. For those young people who are not at school, few directed programs are available in either prevention or cessation and information is needed about the design and delivery of appropriate programs for this population. This report presents the results from a survey of unemployed youth and students at vocational colleges about various aspects of smoking cessation. The majority of out-of-school youth smokers had not tried to quit, but 52% were contemplating action to quit. Only a quarter of the smokers had quit for more than a week. Few young smokers would use a recognised program though more females would change to a lower nicotine brand, quit with the help of a friend or participate in a group quit program. The method of quitting most would recommend to peers is 'use of will power'. Incentives to quit were attractive to only a third of the smokers, and many enhancing and inhibiting factors for participation in programs were identified. In particular, efforts to quit increased their confidence in quitting, supporting the need to assist those who are contemplating action to quit. Programs need to incorporate input from youth and be tailored for them but not necessarily for different groups such as non-secondary school students and unemployed youth.

Adolescent↗

AT1 receptors mediate angiotensin II uptake and transport by bovine brain microvessel endothelial cells in primary culture.

The endothelial lining of the blood-brain barrier tightly controls the distribution of peptide hormones between the central nervous system and the circulation. By using primary cultures of brain microvessel endothelial cells, an in vitro model of the blood-brain barrier, we report here the uptake and transport of the octapeptide angiotensin II by a specific receptor population. With the angiotensin II antagonists losartan (AT1 specific) and PD 123,319 (AT2 specific), we showed that both the uptake and transport of angiotensin II were mediated by the AT1 receptor. Western blot analysis confirmed the existence of the AT1 receptor in our cell-culture model. Rhodamine 123 studies also suggested that both angiotensin II antagonists, but not angiotensin II, were substrates for the P-glycoprotein efflux system, thus restricting the transport of these compounds. These results suggest an AT1 receptor mediates uptake and transport of angiotensin II at the blood-brain barrier and may contribute to the regulation of cerebrovascular levels of the peptide.

Angiotensin II↗

Receptor-mediated angiotensin II transcytosis by brain microvessel endothelial cells.

Angiotensin II (Ang II) uptake and transport across monolayers of bovine brain microvessel endothelial cells (BMECs) was demonstrated. Ang II transport was linear up to 2 h, saturable with a K(m) of 1.7 nM, and tended to be polarized with the apical-to-basolateral transport being greater. [3H]Ang II transport was found to be inhibited by excess unlabeled Ang II, by the Ang II analog sarathrin, and by the endocytic inhibitor phenylarsine oxide. Ang II-(2-8) and-(3-8) were shown to significantly increase the transport of Ang II. These results demonstrate for the first time the receptor-mediated transcytosis of Ang II across brain microvessel endothelium.

Angiotensin II↗

Evaluation of the role of P-glycoprotein in ivermectin uptake by primary cultures of bovine brain microvessel endothelial cells.

The P-glycoprotein efflux system located on the apical membrane of brain capillary endothelial cells functions as part of the blood-brain barrier. In this study, primary cultures of bovine brain microvessel endothelial cells (BMECs) were investigated for the presence of a P-glycoprotein system and its contribution in regulating ivermectin distribution across the blood-brain barrier. Results of rhodamine 123 uptake studies with cyclosporin A and verapamil as substrates indicated that a functional efflux system was present on BMECs. Immunoblot analysis with the C219 monoclonal antibody to the product of the multidrug resistant member 1(MDR1) gene also confirmed the expression of MDR1 in the BMECs. Unbound ivermectin was shown to significantly increase the uptake of rhodamine 123 in BMECs, however, the drug only modestly enhanced the transcellular passage of rhodamine. The results of these studies affirmed that unbound ivermectin is an inhibitor of the MDR1 efflux system in BMECs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Mandibular skeletal and dental asymmetry in Class II subdivision malocclusions.

Mandibular symmetry was compared between a group of 28 subjects exhibiting Class II subdivision malocclusions and 30 subjects with Class I malocclusions who served as the control group. With submentovertex radiographs, symmetry was assessed by measuring the relative difference in spatial position of mandibular landmarks in both anteroposterior and transverse dimensions as determined by coordinate systems representing the cranial floor, mandible, and mandibular dentition. Only those variables representing the anteroposterior difference between right and left mandibular molar positions showed a statistically significant difference between the groups. Whether the position of the mandibular molars was measured relative to the cranial floor or within the mandible itself, the mandibular first molar was located more posteriorly on the Class II side of the subdivision malocclusion within a mandible that exhibited no other unusual asymmetry.

Adult↗

Amino acid substitutions in HIV-1 reverse transcriptase with corresponding residues from HIV-2. Effect on kinetic constants and inhibition by non-nucleoside analogs.

Nevirapine is a highly potent and specific inhibitor of human immunodeficiency virus type 1 (HIV-1) polymerase, but is inactive against HIV-2 and other polymerase. Previous studies demonstrated that residues 176-190 of HIV-1 reverse transcriptase (RT) can confer nevirapine sensitivity to HIV-2 RT. To better characterize the role of this sequence in HIV-1 RT, we have progressively substituted residues 176-190 of HIV-2 RT for those of HIV-1 RT and monitored the impact on the kinetic properties; inhibitory activity of nevirapine (11-cyclopropyl-5,11-dihydro-4-methyl-6H-dipyrido[2,3-b:2',3'-e] [1,4]diazepin-6-one), E-BPU (5-ethyl-1-benzyloxymethyl-6-(phenylthio)-uracil), and TIBO-R82150 ((+)-S-4,5,6,7-tetrahydro-5-methyl-6-(3-methyl-2-butenyl)imidazo[4,5,1-j k] [1,4]benzodiazepin-2(1H)-thione); and inhibitor-induced fluorescence changes of the mutant enzymes. The study revealed that in addition to Try-181 and Tyr-188, a new amino acid residue (Gly-190) plays an important role in determining susceptibility to nevirapine and E-BPU, but not to TIBO-R82150. These data argue that these non-nucleoside inhibitors fit differently, even though they share a common binding pocket. Nevirapine was seen to exert inhibitory activity by altering the interaction of the enzyme with the template-primer. Kinetic parameters were modulated by the template (DNA versus RNA) as well as by some of the mutations.

Amino Acid Sequence↗

Social support and caregiving burden in family caregivers of frail elders.

This study assessed the relationships between six different types of social support and five measures of caregiving burden. Two questions were addressed: Are all types of social support equally associated with burden, and do the same types of support correlate with different types of burden? Family caregivers (N = 217) to frail elders composed the sample. Multiple regression analyses demonstrated that all types of social support for caregivers of frail elders are not equal. Engaging in social interaction for fun and recreation appears to be the most important in diminishing the burden of caregiving. These findings are instructive both theoretically and clinically. The theoretical import of greater social participation under a condition of chronic stress is discussed. Further, interventions that focus on caregivers regularly experiencing pleasant activity with friends and other family would seem to go a long way toward managing the burden of caregiving.

Aged↗

Comparative purification of recombinant HIV-1 and HIV-2 reverse transcriptase: preparation of heterodimeric enzyme devoid of unprocessed gene product.

A procedure for producing and purifying recombinant HIV-1 and HIV-2 reverse transcriptase (RT) is described. These enzymes are produced by Escherichia coli-transformed with a plasmid containing the gene encoding for either the human immunodeficiency virus type 1 (HIV-1) or HIV-2 RT protein. Both proteins are partially processed by host cell proteases giving rise to a mixture of heterodimeric and nonheterodimeric products, which are subsequently resolved to near homogeneity by chromatography on phosphocellulose, Q-Sepharose, and hydrophobic interaction HPLC. Both HIV-1 (66/51 kDa) and HIV-2 (68/54 kDa) heterodimeric enzymes devoid of excess unprocessed (p66 or p68) precursors are isolated, enabling comparative enzymatic characterization of the fully active (and biologically relevant) heterodimeric forms. Homogenous HIV-1 and HIV-2 RT purified by this methodology exhibit near equivalent polymerase and RNase H activities.

Amino Acid Sequence↗

Chimeric human immunodeficiency virus type 1/type 2 reverse transcriptases display reversed sensitivity to nonnucleoside analog inhibitors.

Human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT), an important therapeutic target in the treatment of AIDS, is effectively inhibited by a class of nonnucleoside analog compounds that includes nevirapine (BI-RG-587) and tetrahydroimidazo[4,5,1-jk]-[1,4]benzodiazepin-2(1H)-one and -thione. We show that both tyrosine residues at positions 181 and 188 flanking the putative catalytic site of HIV-1 RT are required for sensitivity of the enzyme to these compounds. HIV-2 RT, which does not have tyrosines at these positions, is resistant to these nonnucleoside analog inhibitors. Substitution of the HIV-2 RT amino acid residues at position 181 or 188 into HIV-1 RT results in an enzyme that is resistant to these compounds while retaining sensitivity to 3'-azido-2',3'-dideoxythymidine triphosphate. HIV-2 RT substituted with amino acids 176-190 from HIV-1 RT acquires sensitivity to these nonnucleoside analog inhibitors.

Affinity Labels↗

Evolutionary conservation of intron position in a subfamily of genes encoding carbohydrate-recognition domains.

The structure of the gene encoding a chicken liver receptor, the chicken hepatic lectin, which mediates endocytosis of glycoproteins has been established. The coding sequence is divided into six exons separated by five introns. The first three exons correspond to separate functional domains of the receptor polypeptide (cytoplasmic tail, transmembrane sequence, and extracellular neck region), while the final three exons encode the Ca(2+)-dependent carbohydrate-recognition domain. These results, as well as computer-assisted multiple sequence comparisons, establish this receptor as the evolutionary homolog of the mammalian asialoglycoprotein receptors. It is interesting that the chicken receptor falls into a subfamily of proteins along with the mammalian asialoglycoprotein receptors, since the saccharide-binding specificity of the chicken receptor resembles more closely that of a different set of calcium-dependent animal lectins, which includes the mannose-binding proteins. The portions of the genes encoding the carbohydrate-recognition domains of these proteins lack introns. The results suggest that divergence of intron-containing and intron-lacking carbohydrate-recognition domains preceded shuffling events in which other functional domains were associated with the carbohydrate-recognition domains. This was followed by further divergence, generating a variety of saccharide-binding specificities.

Amino Acid Sequence↗

Review of Aeromonas enterotoxins.

This report reviews the work of other investigators regarding Aeromonas toxins and describes work conducted in our laboratory relating to the biochemical characterization of a cytolytic factor with an antigenic moiety that cross-reacts with cholera toxin (referred to as CTC-cytolysin), as well as the purification and partial characterization of a non-CTC enterotoxin. These two toxins were produced by Aeromonas hydrophila, isolate SSU, and are capable of causing fluid accumulation in animal models.

Aeromonas↗

Dimensions of perceived social support in clinically depressed and nondepressed female caregivers.

The relationship between social support and depression was studied in 165 women caring for frail family members. The Arizona Social Support Interview Schedule (Barrera, Sandler, & Ramsay, 1981), which includes 4 dimensions of availability and use of resources and satisfaction with and need for support, was used to examine 7 categories of supportive activity. Depression was assessed according to Research Diagnostic Criteria (Spitzer, Endicott, & Robins, 1978) with the Schedule of Affective Disorders and Schizophrenia (Endicott & Spitzer, 1978). There were no differences in overall satisfaction with received support in comparisons of depressed and nondepressed caregivers. However, depressed caregivers (n = 87) reported a higher incidence of negative interactions with others. Both groups appeared to have equal access to social support, with nondepressed caregivers (n = 78) reporting significantly greater use of those resources.

Activities of Daily Living↗

Seroreactive recombinant herpes simplex virus type 2-specific glycoprotein G.

The herpes simplex virus type 2 (HSV-2) genome codes for an envelope protein, glycoprotein G (gG), which contains predominantly type 2-specific epitopes. A portion of this gG gene has been expressed as a fusion protein in Escherichia coli. Expression was regulated by a lambda phage pL promoter. The 60,000-molecular-weight recombinant protein was purified by ion-exchange chromatography. Amino acid sequence analysis confirmed the N terminus of the purified protein. Mice immunized with recombinant gG developed antibodies reactive with native HSV-2 protein, but not with HSV-1 protein, in an indirect immunofluorescence assay. The serological activity of this purified recombinant gG protein was evaluated by immunoblot assay. This protein was reactive with an HSV-2 gG monoclonal antibody. It was also reactive with HSV-2 rabbit antiserum but not with HSV-1 rabbit antiserum. Of 15 patient serum samples known to have antibody to HSV-2, 14 were reactive with this recombinant type 2-specific gG protein, and none of 15 HSV antibody-negative patient serum samples showed reactivity. In agreement with the expected prevalence of HSV-2 infection, 27.6% of 134 serum samples from random normal individuals had antibodies reactive with recombinant gG. This recombinant gG protein may be of value in detecting HSV-2-specific antibody responses in patients infected with HSV-2.

Adult↗

Separation-individuation conflict as a model for understanding distressed caregivers: psychodynamic and cognitive case studies.

Caring for a frail relative can be a stressful undertaking. Caregivers are faced with a series of losses, and old interpersonal wounds are often reopened. Project Assist was designed to study the efficacy of time-limited psychodynamic and cognitive/behavioral therapies for experienced and recent caregivers. It offers psychotherapy that can assist caregivers in separating their own emotions, identity, and well-being from those of the care receiver. This process appears necessary for the individuation and mental health of caregivers.

Aged↗

Purification and chemical characterization of a cholera toxin-cross-reactive cytolytic enterotoxin produced by a human isolate of Aeromonas hydrophila.

A bacterial protein toxin possessing hemolytic, enterotoxic, and cytotoxic activities as well as cross-reactivity to cholera toxin was purified from culture filtrates of a human diarrheal isolate of Aeromonas hydrophila (SSU). This cytolytic enterotoxin was purified by ammonium sulfate precipitation, hydrophobic chromatography using phenyl-Sepharose, anion-exchange chromatography on DEAE-Bio-Gel A, and size-exclusion high-performance liquid chromatography. The factor was a single polypeptide with an apparent molecular weight of 52,000 as determined by polyacrylamide gel electrophoresis. Automated amino acid sequence analysis confirmed that the toxin was a single chain and established a 25-residue N-terminal segment which was identical to that of aerolysin purified from culture supernatants of A. hydrophila isolate Ah65 originally obtained from rainbow trout as reported by Howard et al. (S. P. Howard, W. J. Garland, M. J. Green, and J. T. Buckley, J. Bacteriol. 169:2869-2871, 1987). However, the amino acid compositional analysis of the toxin produced by our human isolate (SSU) differed significantly from that of the Ah65 isolate. Taken together, these results strongly indicated that several toxic phenomena associated with A. hydrophila (SSU) culture filtrates, including hemolysis, cytotoxicity, and enterotoxicity as well as cross-reactivity to cholera toxin, all can occur on a single polypeptide. In addition, these results underline the fact that although aerolysin-related toxins isolated from culture filtrates of A. hydrophila are biologically similar, significant chemical and immunological differences may exist between toxins produced by individual isolates.

Aeromonas↗

Bioactivity and immunological characterization of a cholera toxin-cross-reactive cytolytic enterotoxin from Aeromonas hydrophila.

A cytolytic enterotoxin of molecular weight 52,000 was isolated and purified from culture supernatants of a human diarrheal isolate (SSU) of Aeromonas hydrophila. The toxin reacted with cholera antitoxin when tested in an enzyme-linked immunosorbent assay and by Western blot (immunoblot) analysis. The appearance of cytotoxic and hemolytic activities in culture supernatant occurred simultaneously 8 h after the initial inoculation of the culture. Loss of hemolytic activity and cholera toxin cross-reactivity was correlated with heat and pH inactivation. Homologous antibodies neutralized the cytotoxic and hemolytic activities associated with the toxin, but cholera antitoxin did not neutralize these activities. The toxin also possessed enterotoxic activity as demonstrated by fluid accumulation in rabbit ligated intestinal loops. When purified cytolytic enterotoxin was injected intravenously into mice, death occurred within 2 min, whereas mice injected with whole cells or sonicated cell fragments died after several hours or days. Results from 51Cr release experiments demonstrated that the cytolytic enterotoxin had significant membrane-damaging capability. These results indicated that the cytolytic and enterotoxic activities expressed by the described A. hydrophila toxin may contribute significantly to the pathogenesis of disease associated with A. hydrophila.

Aeromonas↗