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Biomedical subjects

D Higgins

Publications and source records attributed to D Higgins.

At least 55 records · Page 3Linked to original sources
PubMed1996

Non-gay-identifying men who have sex with men: formative research results from Seattle, Washington.

Non-gay-identifying men who have sex with men are at risk for human immunodeficiency virus (HIV) infection. To understand these men and to develop interventions to reduce their HIV risks, the authors interviewed staff at agencies that serve non-gay-identifying men who have sex with men, business people who interact with them, and the men themselves. Interviews were augmented with focus groups of non-gay-identifying men who have sex with men and field observations at sites identified as places where they meet to negotiate or have sex. These qualitative data suggested 73 possible groups, which were consolidated into 16 broader "sectors," and then formally ranked by level of HIV risk, ease of access to the sector, psychosocial risks, and influence of other local interventions or research activities. The authors identified six priority groups of non-gay-identifying men who have sex with men (and sites where members of these groups could be approached): hustlers, closeted men, experimenters, incarcerated or formerly incarcerated men, men of color, and heterosexually identified bisexuals. Masturbation and oral sex were reportedly common, but anal and vaginal sex were also noted; condom use was rarely reported. Risk behaviors among non-gay-identifying men who have sex with men persist for a variety of reasons and may require a variety of intervention approaches.

Adolescent↗
PubMed1996

Developing community networks to deliver HIV prevention interventions.

Outreach has a long history in health and social service programs as an important method for reaching at-risk persons within their communities. One method of "outreach" is based on the recruitment of networks of community members (or "networkers") to deliver HIV prevention messages and materials in the context of their social networks and everyday lives. This paper documents the experiences of the AIDS Community Demonstration Projects in recruiting networkers to deliver HIV prevention interventions to high-risk populations, including injecting drug users not in treatment; female sex partners of injecting drug users; female sex traders; men who have sex with men but do not self-identify as gay; and youth in high-risk situations. The authors interviewed project staff and reviewed project records of the implementation of community networks in five cities. Across cities, the projects successfully recruited persons into one or more community networks to distribute small media materials, condoms, and bleach kits, and encourage risk-reduction behaviors among community members. Networkers' continuing participation was enlisted through a variety of monetary and nonmonetary incentives. While continuous recruitment of networkers was necessary due to attrition, most interventions reported maintaining a core group of networkers. In addition, the projects appeared to serve as a starting point for some networkers to become more active in other community events and issues.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Molecular characterization of leukocyte adhesion deficiency in six patients.

Leukocyte adhesion deficiency (LAD) is caused by defects in the CD18 gene, which codes for the common beta 2 subunit of the leukocyte integrins LFA-1, Mac-1 and p150,95. Failure to produce a functional beta 2 subunit results in the defective expression of all three leukocyte integrins, and the leukocytes of LAD patients have subnormal adhesion properties. Six patients with LAD were studied. Patient B was homozygous and carried a G284S mutation. A two-bp (GA) deletion at position 1256 (1256 delta GA) was found in the cDNA of patient C, who also had an abnormally large mRNA of 4.3 kb. Patients E and K were siblings and were heterozygous at the genomic level. One defective allele contained a mutation in intron 6/7 which created a preemptive 3' splice site. The resulting mRNA has 12 extra bases at the junction of exons 6 and 7, coding for four extra residues PSSQ in the protein. The same allele also carried a R586W mutation. The other allele was transcribed at a low level and was not characterized. Patient G carried a L149P mutation in one allele; again, the other allele was not characterized due to low transcription levels. Patient R carried two mutant alleles with G284S and R593C mutations respectively. The G284S mutation and the 1256 delta GA deletion have not been reported previously. CD18 cDNA carrying the abnormalities were cotransfected with normal CD11a or CD11b cDNA into COS cells. Expression of the LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) antigens on COS cells was not detected, suggesting that these two mutations are sufficient to account for LAD.

Alleles↗
PubMed1995

Osteogenic protein-1 induces dendritic growth in rat sympathetic neurons.

Sympathetic neurons from perinatal rat pups extend only a single axon when maintained in culture in the absence of glia and serum. Exposure to recombinant osteogenic protein-1 (OP-1) selectively induces the formation of dendrites that correctly segregate and modify cytoskeletal and membrane proteins and form synaptic contacts of appropriate polarity. OP-1 requires nerve growth factor (NGF) as a cofactor, and, in the presence of optimal concentrations of NGF, OP-1-induced dendritic growth from cultured perinatal neurons is comparable to that observed in situ. Sympathetic neuroblasts that had not formed dendrites in situ also responded to OP-1 in culture, indicating that OP-1 can cause de novo formation as well as regeneration of dendrites. These data imply that specific signals can regulate the development of neuronal shape and polarity.

Animals↗
PubMed1995

Awake oral fibreoptic intubation for caesarean section.

A 35-week pregnant patient with ankylosing spondylitis and a known previous failed intubation required an elective caesarean section for intrauterine growth retardation. Regional anaesthesia was prevented by extensive spinal fusion. The anaesthetic management involved an awake oral fibreoptic intubation followed by induction and maintenance of general anaesthesia allowing delivery of a live infant without harm to the mother.

Journal Article↗
PubMed1994

Low intramucosal pH is associated with failure to acidify the gastric lumen in response to pentagastrin.

OBJECTIVE: To determine if low gastric intramucosal pH is associated with impaired secretion of gastric acid after pentagastrin stimulation. DESIGN: Prospective study. SETTING: Intensive care unit of a university teaching hospital. PATIENTS: 20 patients requiring mechanical ventilation. INTERVENTIONS: All patients with a gastric luminal pH > 4 were given pentagastrin 6 micrograms/kg s.c. to stimulate gastric acid secretion and the response assessed by further measurements of gastric luminal pH. MEASUREMENTS AND RESULTS: Gastric intramucosal pH (pHi) and luminal pH (pHL) were measured. Patients were divided into two groups on the basis of a low or normal pHi (A value of 7.35 was taken as the lower limit of normal). Patients (n = 6) with normal pHi (7.40 +/- 0.05 [mean +/- SD]) and a luminal pH > 4 (5.65 +/- 1.25) all had a decrease in pHL in response to pentagastrin (decrease in pHL 4.02 +/- 1.52). Of the patients (n = 7) with low pHi (7.2 +/- 0.13) and a pHL > 4 (6.51 +/- 0.48) only one responded to pentagastrin (decrease in pHL for this group 0.93 +/- 1.86). Patients with a pHL < 4 (2.4 +/- 0.71) were not given pentagastrin (n = 7). CONCLUSION: Some critically ill patients with low gastric intramucosal pH appear to have an impaired ability to acidify the gastric lumen in response to pentagastrin.

Achlorhydria↗
PubMed1993

Manganese induces spreading and process outgrowth in rat pheochromocytoma (PC12) cells.

Mn2+ has been shown to promote cell-substrate adhesion and cell spreading in many cell culture systems. In this study, we present data demonstrating that Mn2+ not only promotes spreading, but also induces process outgrowth in rat pheochromocytoma (PC12) cells. In the presence of 1.0 mM MnCl2, cell spreading was apparent by 6 hr, and nearly 50% of the exposed cells extended neurite-like processes. These morphological effects of Mn2+ were both time- and dose-dependent. In the presence of cycloheximide, a protein synthesis inhibitor, both Mn(2+)-induced spreading and neurite outgrowth were prevented, indicating that de novo protein synthesis is required for the effects of Mn2+ to take place. Of the other divalent cations tested, Mg2+, Cd2+, Cu2+, Ni2+, and Zn2+ were ineffective, and only Co2+ partially mimicked the effects of Mn2+. Although Mn(2+)-induced cell adhesion and spreading have been extensively studied, this is the first report that this divalent cation can cause neurite outgrowth. The neurite outgrowth-promoting effects of Mn2+ were distinct from those of nerve growth factor in that the response to Mn2+ was considerably more rapid, but apparently lacked the ability to sustain continuous outgrowth and networking of neurites. Mn2+ also induced the levels of GAP-43 and peripherin, two proteins associated with neuronal differentiation of PC-12 cells. In cells grown in serum-free defined medium, Mn2+ was capable of promoting neurite outgrowth when the cells were plated on surfaces pretreated with normal growth medium, vitronectin, or fibronectin, while it failed to cause these morphological changes in cells plated on untreated or poly-D-lysine-coated substrata. Similarly, Mn2+ also promoted neurite outgrowth from rat sympathetic neurons attached to laminin-treated substrate, but had no effect on neurons maintained on substrate with polylysine only. The pentapeptide Gly-Arg-Gly-Asp-Ser nearly completely prevented the morphological effects of Mn2+ on PC12 cells. These findings are consistent with a hypothesis that Mn(2+)-mediated alteration of an RGD-dependent extracellular matrix-integrin interaction is responsible for the neuritogenic effects.

Amino Acid Sequence↗
PubMed1993

Use of focus group methodology to develop an asthma self-management program useful for community-based medical practices.

Health education programs developed in academic medical centers are not optimally disseminated to community clinical settings. Strategies are needed to translate the findings of research on health education programs into programs useful in a wide range of health care settings. Focus group techniques were used to provide data for revising a successful university-based asthma self-management program to make it more practical for use by community physicians. Physicians representing a variety of specialties attended the sessions and provided feedback on the utility of various components of the original program. The discussions revealed that many physicians felt they did not have the time or resources to conduct the original program and identified elements viewed as impractical. This physician input contributed significantly to the development of a revised program with a briefer, less costly intervention. The revised program was later evaluated by focus group participants. Eighty-eight percent of those who evaluated the revised program agreed they would be able and willing to use the program in their own practices. As a formative evaluation tool, the focus group technique made available useful information that would have been difficult to obtain through evaluation forms alone.

Adult↗
PubMed1992

Laminin selectively enhances axonal growth and accelerates the development of polarity by hippocampal neurons in culture.

We have examined the effects of laminin on the morphological development of embryonic rat hippocampal neurons maintained in tissue culture. Forty-eight hours after plating, neurons grown on a polylysine-coated substrate had become polarized, typically having one long axon and 4 or 5 minor processes. Adsorption of laminin to the substrate did not cause changes in the number of axons extended by hippocampal neurons but did cause significant increases in the length of the axonal plexus and in axonal branching. In contrast to its effects on axons, laminin did not influence the number, length, or branching of the minor processes that eventually become dendrites or the morphology of definite dendrites as assessed after 7 days in culture. In addition to selectively enhancing axonal growth, laminin greatly increased the rate of polarization of hippocampal neurons such that most became polarized within 18 h. Analysis of the time course of laminin's effects revealed that the acceleration of polarization was not associated with a change in the time of initial process formation, but rather with a selective stimulation of the growth of the longest process at all times from the 12th through the 48th h in vitro. These data suggest that even though the basic shape of hippocampal neurons may be intrinsically programmed, critical aspects of their morphological development may be modulated by extracellular matrix molecules such as laminin.

Animals↗