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Biomedical subjects

J Gibbons

Publications and source records attributed to J Gibbons.

At least 37 records · Page 2Linked to original sources
PubMed1993

3H-GABA administration during tail regeneration of lizards and autoradiographical localization.

Thirteen lizards (Anolis carolinensis and Scincella lateralis) were injected with 3H-GABA (tritiated gamma-aminobutyric acid) in order to study its localization inside the regenerating tail spinal cord (SC) by means of light and electron microscopic autoradiography. One and three hours after intraperitoneal injection, the radioactivity was essentially localized in regenerating nerves and pale cells, mostly contacting the central canal of the SC as typical Cerebrospinal-Fluid-Contacting-Neurons (CSFCNs). A smaller number of pale cells did not take up 3H-GABA and some of them appeared to be degenerating. Weaker radioactivity in regenerating SC was observed 6 hours post injection. Among non neural tissues, cells of the regenerating blastema, of the meninges and capillaries surrounding the regenerating SC, showed lower 3H-GABA uptake. This indicates that a certain amount of injected 3H-GABA has been converted to other metabolites. No 3H-GABA uptake was detected 1 or 6 hours post injection in normal SC and brain both in grey and white matter. This research indicates that CSFCNs of the regenerating tail in lizards uptake the aminoacid GABA or derived aminoacids, suggesting these cells subserve a high metabolic activity and may be GABA-ergic

Animals↗
PubMed1992

Fine structure of cells in the young regenerating spinal cord of the lizard Anolis carolinensis after H3-thymidine administration.

H3-thymidine was injected in a single dose into adult lizards Anolis carolinensis during early stages of tail regeneration when the new tail measured in length 2-5 mm (about 3 weeks). Electron microscopic autoradiography revealed that in the regenerating spinal cord three different cell types were recognizable four hours post-injection. By far the most common type was the ependymal cell. Ependymal or roundish cells with clear electron-density or storing bundles of intermediate filaments were occasionally found. A second rarer, cell type devoid of intermediate filaments was a pale round cell, often highly labelled. This cell showed a very poor ultrastructural differentiation and probably represents the precursor of the few neurons and glial cells observed in older stages of regeneration. The third type was a neuroblast at different degrees of differentiation and did not uptake H3-thymidine revealing it was a post-mitotic cell. Despite the relatively advanced ultrastructural differentiation of these neurons, synapses were rarely seen after three weeks of SC regeneration in Anolis.

Animals↗
PubMed1991

Patient and family perceptions of hospital chaplains.

While most hospitals provide chaplaincy services for patients, families, and staff, these services are seldom studied and their contribution is poorly understood. A questionnaire created by the College of Chaplains of the American Protestant Health Association was mailed by an insurance company to patients recently dismissed from the hospital, requesting evaluation of three non-medical services (social services, chaplaincy, and patient representatives) and how well the spiritual needs for support/counseling, prayer, and sacraments were met. Responses revealed that, in comparison to the other two non-medical services, patients receive more visits from chaplains, evaluate these visits as more important (p less than 0.000), and report that these visits meet their expectations more highly (p less than 0.000). Regression analyses demonstrate that when the chaplain meets the patient's need for support/counseling, the respondent is more likely to select the hospital again (p = 0.04) and recommend it to others (p = 0.05). Similarly, when chaplains meet the family's need for support/counseling, the respondent is likely to choose the hospital again. Since chaplains clearly make an important contribution to patients, their families, and the hospital, administrators should review the adequacy of their chaplaincy services in the light of these data.

Attitude to Health↗
PubMed1990

Silent infections with human immunodeficiency virus type 1 are highly unlikely in multitransfused seronegative hemophiliacs.

We used the polymerase chain reaction (PCR) to determine the frequency of silent human immunodeficiency virus type 1 (HIV-1) infections in seronegative high-risk individuals with hemophilia who had been exposed to contaminated blood products more than 3 years previously. In a cross-sectional study of a cohort of 57 prospectively followed seronegative hemophiliacs who received multiple transfusions before 1986, HIV-1 proviral DNA was found transiently in only one patient. These data suggest that the rate of HIV infection among high-risk antibody negative individuals with hemophilia is very low to absent, in the range of 0% to 2%. These findings should provide considerable reassurance to seronegative persons with hemophilia and their sexual partners.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Relationship of racial stressors to blood pressure responses and anger expression in black college students.

The physiological effects of racism, as a stressor, were examined as they related to blood pressure (BP) and anger experiences in Black college students. Current research has failed to consider the stressful effects of racism as a factor contributing to the higher incidence of essential hypertension among Blacks. Twenty-seven Black college students viewed three excerpts showing racist situations involving Blacks; anger-provoking, nonracist situations; and neutral situations. After each scene, BP was taken, and a mood checklist was administered. The Framingham Anger Scale and the Anger Expression Scale were administered. Analyses revealed that BP significantly increased during the presentation of racist stimuli but not of anger-provoking or neutral stimuli. Self-reports of state anger, as measured by the mood checklist, were significant for both the anger-provoking and racist stimuli. BP scores were significantly correlated to the two trait anger measures. Exposure to racist stimuli was associated with BP increases among Blacks. Such cumulative exposure to racism may have important implications for the etiology of essential hypertension.

Adaptation, Psychological↗
PubMed1989

Inhibited and uninhibited types of children.

An initial group of 100 children who were not selected a priori on any behavioral features were observed in laboratory settings at 14, 20, 32, and 48 months and their behaviors coded for inhibition and lack of inhibition to the unfamiliar. The children who had been extremely inhibited or uninhibited at both 14 and 20 months differed significantly at 4 years of age in behavior and cardiac acceleration to cognitive stress. However, for the entire sample, there was no significant relation between degree of inhibited behavior at 14 or 20 months, on the one hand, and inhibition at 4 years of age, on the other, nor any relation between behavior and heart rate acceleration. These results suggest that the constructs inhibited and uninhibited to the unfamiliar refer to children who fall at the extremes of a phenotypic continuum from shyness and restraint to sociability and affective spontaneity.

Cognition↗
PubMed1988

Extensive variation of human immunodeficiency virus type-1 in vivo.

Genotypic variation among independent isolates of human immunodeficiency virus type-1 (HIV-1) is well known, but its molecular basis and biological consequences are poorly understood. We examined the genesis of molecular variation in HIV-1 by sequential virus isolations from two chronically infected individuals and analysis of recombinant HIV-1 genomic clones. In three different virus isolates full-length HIV-1 clones were identified and found to consist, respectively, of 17, 9 and 13 distinguishable, but highly-related, viral genotypes. Thirty-five viral clones derived from two HIV-1 isolates obtained from the same individual but 16 months apart showed progressive change, yet were clearly related. Similar changes in the HIV-1 genome did not occur in vitro during virus isolation and amplification. The results indicate that HIV-1 variation in vivo is rapid, that a remarkably large number of related but distinguishable genotypic variants evolve in parallel and coexist during chronic infection, and that 'isolates' of HIV-1, unless molecularly or biologically cloned, generally consist of complex mixtures of genotypically distinguishable viruses.

Base Sequence↗
PubMed1988

Risk of human immunodeficiency virus (HIV-1) infection among laboratory workers.

In a prospective cohort study of 265 laboratory and affiliated workers, one individual with no recognized risk factors for human immunodeficiency virus type 1 (HIV-1) infection was HIV-1 seropositive at the time of entry into the study. Molecular analyses of two HIV-1 isolates derived in two independent laboratories from a blood sample from this worker showed that the isolates were indistinguishable from a genotypic form of HIV-1 present in the H9/HTLV-IIIB cell line. Exposure to this strain of virus most probably occurred during work with concentrated virus or culture fluids from virus-producing cell lines under standard Biosafety Level 3 containment. Although no specific incident leading to this infection has been identified, undetected skin contact with virus culture supernatant might have occurred. This worker was the only one found to be positive among the subgroup of 99 workers who shared a work environment involving exposure to concentrated virus. The incidence rate of 0.48 per 100 person-years exposure indicates that prolonged laboratory exposure to concentrated virus is associated with some risk of HIV-1 infection, which is comparable to the risk for health care workers experiencing a needle stick exposure. While none of the ten workers with parenteral exposure to HIV-1 in this cohort became infected, a worker in another laboratory did seroconvert following an injury with a potentially contaminated needle. Strict Biosafety Level 3 containment and practices should be followed when working with concentrated HIV-1 preparations, and further refinement of the procedures may be necessary.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Do object relations deficits distinguish BPD from other diagnostic groups?

Two independent samples that met DSM-III criteria for borderline personality disorder (BPD) were found to have similar patterns of object relations deficits as measured by group means and percentage of high scoring subjects on the four subscales of the Bell Objects Relation (OR) Inventory. Statistical comparison of the composite BPD group with affective, schizoaffective, and schizophrenic groups revealed that the pattern of OR deficits in BPD was significantly different from each of the other diagnostic groups. On the basis of scores from the Alienation subscale alone, BPD subjects could be distinguished from the other diagnostic groups with 77-82% predictive accuracy. The role of object relations deficits in BPD is discussed, along with potential contributions of the Bell OR Inventory to diagnostic efficiency.

Adult↗
PubMed1988

Childhood derivatives of inhibition and lack of inhibition to the unfamiliar.

Behavioral and physiological assessments of 41 7 1/2-year-old children who had been selected to be inhibited or uninhibited at 21 months and observed again at 4 and 5 1/2 years revealed that each of the 2 original behavioral profiles predicted theoretically reasonable derivatives. A majority of the formerly shy, timid children became quiet and socially avoidant in unfamiliar social situations, while a majority of the formerly sociable children became talkative and interactive with peers and adults. Absolute heart-rate and cortisol level at 7 1/2 years were not as discriminating of the 2 behavioral groups as they had been 2 years earlier.

Arousal↗
PubMed1988

Cell culture studies and oncogene expression in juvenile chronic myelogenous leukemia.

Juvenile chronic myelogenous leukemia (JCML) may be distinguished from adult CML based upon in vitro cell growth characteristics. We studied four untreated children with JCML and report additional unique findings. Peripheral blood (PB) and bone marrow (BM) cells were grown in soft agar. Without exogenous colony-stimulating activity (CSA) there was exuberant "spontaneous" colony formation in both PB and BM cultures. In the absence of exogenous stimulus, PB colony morphology was predominantly, but not exclusively, monocyte/macrophage. When PB was depleted of adherent cells, "spontaneous" colony formation was nearly completely abrogated. Cultures were also performed in the presence of various sources of CSA including giant cell tumor-conditioned medium (GCT-CM), a melanoma cell line-CM (LD1-CM), human placenta-CM (HPCM), and normal PB mononuclear cell (PBMC) feeder layers. Colony formation was typically increased with HPCM and PBMC, whereas in two patients GCT-CM and LD1-CM failed to stimulate additional colony growth when compared to cultures without exogenous CSA and, in fact, appeared to inhibit baseline "spontaneous" growth. The morphology of colonies in the presence of exogenous stimuli was highly variable. Because of the recent association between the c-fms protooncogene product and the receptor for the monocyte growth factor CSF-1, we analyzed the PB cells from two JCML patients for c-fms expression. Although expressed, c-fms levels were less than that in an adult with Ph1-positive CML in chronic phase. These studies indicate that in JCML, there are dramatic increases in both PB and BM colony-forming cells and that "spontaneous" growth is dependent on an accessory adherent cell fraction. Furthermore, patterns of responsiveness to various sources of CSA suggest that the colony-forming cells may not be a uniform population of malignant cells.

Animals↗
PubMed1987

A portable silicon photodiode luminometer.

A simple, inexpensive, battery-powered, portable luminometer which is based on a silicon photodiode is described. The instrument is intended to measure the light produced by chemiluminescent and bioluminescent reactions. The device shows a good detection limit and, in a bioluminescent reaction for adenosine 5'-triphosphate (ATP), detected 0.5 pmol in 1 ml of aqueous solution. The instrument measures irradiance from 10(-13) to 10(-11) W cm-2 at the sensor, within the range 300 to 900 nm.

Adenosine Triphosphate↗