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Biomedical subjects

P Nelson

Publications and source records attributed to P Nelson.

At least 73 records · Page 4Linked to original sources
PubMed1996

Earth benefits of interdisciplinary CELSS-related research by the NSCORT in Bioregenerative Life Support.

Earth benefits of research from the NSCORT in Bioregenerative Life Support will include the following: development of active control mechanisms for light, CO2, and temperature to maximize photosynthesis of crop plants during important phases of crop development; automation of crop culture systems; creation of novel culture systems for optimum productivity; creation of value-added crops with superior nutritional, yield, and waste-process characteristics; environmental control of food and toxicant composition of crops; new process technologies and novel food products for safe, nutritious, palatable vegetarian diets; creation of menus for healthful vegetarian diets with psychological acceptability; enzymatic procedures to degrade recalcitrant crop residues occurring in municipal waste; control-system strategies to ensure sustainabilty of a CELSS that will enable management of diverse complex systems on Earth.

Biomass↗
PubMed1996

Span of apprehension deficits in older outpatients with schizophrenia.

Performance on the span of apprehension task, a well-studied information processing task in schizophrenia research, was examined in 11 schizophrenia patients and 11 normal comparison participants, all over the age of 45 years. Subjects detected "T' and "F' targets in briefly-flashed arrays of 1, 6, and 12 letters on the span task. Consistent with previously reported findings in younger schizophrenia patients, the older patients detected significantly fewer targets in the larger (12-letter), but not smaller (1-, or 6-letter), arrays. The older schizophrenia patients also showed significantly slower reaction times in all array-size conditions. Neither age of onset nor duration of illness was significantly correlated with span task performance. The characteristic span of apprehension task deficit found in the older schizophrenia patients suggests that late-life schizophrenia shares a common cognitive impairment with childhood and young adulthood schizophrenia, and provides supportive evidence for a possible stable vulnerability trait deficit in schizophrenia that is independent of age of onset and duration of illness.

Age Factors↗
PubMed1996

Neuropsychological rehabilitation of mild traumatic brain injury.

A significant minority of patients who have sustained a mild traumatic brain injury (MTBI) may exhibit persistent disability. There have been few attempts to describe and evaluate the effectiveness of neurorehabilitation for these patients. We conducted a retrospective analysis of the results of a neuropsychological rehabilitation programme for 20 patients with MTBI. Based upon the ability to resume productive functioning after treatment, 10 patients were determined to exhibit a good outcome and 10 patients were considered to exhibit a poor outcome. Patients with good outcome exhibited significant pre-post-treatment improvements on both neuropsychological measures of cognitive functioning and self-reported post-concussive symptoms. Patients with poor outcome demonstrated little improvement in either area, and in some cases showed a decline in functioning. The results are consistent with the view that there may be significant variability in recovery and response to treatment after MTBI. There is a continued need to identify which patients may benefit from neurorehabilitation, develop specially tailored interventions, and conduct controlled, prospective studies in this area.

Adult↗
PubMed1995

The impact of knowledge of human immunodeficiency virus serostatus on contraceptive choice and repeat pregnancy.

OBJECTIVE: To examine relationships among human immunodeficiency virus (HIV) serostatus, postpartum contraceptive choice, and the rate of repeat pregnancy within a short interval. METHODS: This retrospective cohort study was performed in 83 seropositive and 218 seronegative women identified from an inner-city prenatal population undergoing routine voluntary HIV antibody screening from July 1987 through June 1989. Postpartum contraceptive choices and rate of repeat pregnancies were compared based on HIV serostatus. RESULTS: Seropositive women were significantly more likely than seronegative women to undergo tubal sterilization (27 versus 15%; odds ratio [OR] 2.9, 95% confidence interval [CI] 1.5-5.9). This relationship persisted after controlling for age, race, marital status, and parity by logistic regression modeling (adjusted OR 2.9, 95% CI 1.4-5.9). Seropositive women were significantly less likely than seronegative women to select oral contraceptives (34 versus 68%; OR 0.2, 95% CI 0.1-0.4), a relationship that persisted after controlling for age, race, marital status, parity, and foam and condom use (adjusted OR 0.2, 95% CI 0.1-0.5). Seropositive women were significantly more likely than seronegative women to select foam and condoms as their primary method of contraception (30 versus 15%; OR 2.4, 95% CI 1.2-4.5), a relationship that did not persist after controlling for age, race, marital status, and parity (adjusted OR 0.7, 95% CI 0.4-1.3). The risk of repeat pregnancy was slightly lower in seropositive versus seronegative women (34 versus 44%; OR 0.7, 95% CI 0.4-1.3). Most repeat pregnancies among seropositive and seronegative women were unplanned (90 and 82%, respectively). CONCLUSION: There was a relationship between the method of postpartum contraception and HIV serostatus, but no significant difference in repeat pregnancy rates associated with choice of method.

Adolescent↗
PubMed1995

Therapeutic effects of diethylcarbamazine and 3'-azido-3'-deoxythymidine on feline leukemia virus lymphoma formation.

Twenty-four specific pathogen-free kittens were infected with the Rickard strain of feline leukemia virus (FeLVR). The kittens were divided into four equal groups and were orally administered either a high dose of diethylcarbamazine (DECH, 12 mg kg-1), a low dose of diethylcarbamazine (DECL, 3 mg kg-1), 3'-azido-3'-deoxythymidine (AZT, 15 mg kg-1, b.i.d.), or a placebo (250 mg granular dextrose) daily for 10 weeks. Blood was collected at 2-week intervals for complete blood counts (CBC) and flow cytometric analysis (FACS) of peripheral blood lymphocytes (PBL). Plasma was assayed for antibodies to FeLV gp70 and for FeLV p27 antigen using ELISA assays. For FACS analysis, lymphocytes were incubated with monoclonal antibodies to feline Pan T, CD8+, CD4+, and B cell (Anti-Ig) antigens. In the placebo treated cats, FeLVR infection caused an early (2 weeks p.i.) and persistent decrease in leukocyte numbers attributable primarily to a decrease in neutrophil numbers and a secondary lesser decrease in B and CD4+ lymphocyte numbers. The DEC-treated groups showed a delayed but similar leukopenia by 4 weeks p.i. The lymphopenia in the DEC groups (primarily B cells and CD4+ cells) was reversed by 10 weeks p.i., but the neutropenia persisted. AZT treatment inhibited FeLVR-induced lymphopenia but did not prevent a reduction in neutrophil numbers. A marked p27 antigenemia that peaked at 4 weeks p.i. was noted in the placebo treated cats and in most cats (11/12) treated with either dose of DEC. However, AZT significantly inhibited the p27 antigenemia and all cats were negative for p27 antigen between 6 and 10 weeks of treatment. In general, placebo treated cats as well as DECH and DECL cats had low levels of antibody to gp70 throughout the study, suggesting FeLVR-induced immunosuppression. In contrast, significantly higher titers of anti-gp70 antibodies were seen in AZT-treated cats at 6 weeks p.i., and were maintained throughout treatment. Eighteen month survival rates provide efficacy data for AZT as well as both DEC treatment groups. While all placebo treated cats were euthanized by 52 weeks p.i. due to FeLV associated lymphomas with a mean survival time of 35.5 weeks p.i., median survival time of the AZT treated group was > or = 102 weeks p.i., while that of the DECH and DECL groups was 69.7 and 72 weeks p.i., respectively. Thus, DEC as well as AZT therapy delays the development of lymphomas associated with FeLV infection and significantly improves survival.

Animals↗
PubMed1994

IgMs produced by two acquired immune deficiency syndrome lymphoma cell lines: Ig binding specificity and VH-gene putative somatic mutation analysis.

Two B-cell lines, 2F7 and 10C9, were established by single cell cloning from biopsies obtained from two acquired immune deficiency syndrome patients with Burkitt's lymphoma. Representation of the original tumors was verified by demonstration of (1) identical biallelic rearrangement of Ig genes for 2F7 and (2) shared idiotype for 10C9. Both cell lines displayed cell-surface Ig and secreted Ig (IgM lambda for 2F7, IgM kappa for 10C9). IgMs from both cell lines immunoprecipitated actin; in addition, 2F7 IgM lambda immunoprecipitated recombinant human immunodeficiency virus type 1 (HIV-1) gp 160. 2F7 IgM lambda did not react with other autoantigens (double-stranded and single-stranded DNA, actin, bovine serum albumin, IgG), whereas 10C9 IgM kappa reacted with human IgG. The 2F7 IgM heavy-chain variable region (VH) showed a 95% nucleotide homology with a previously sequenced VHIII germline gene, hv3019b9, whereas the 10C9 IgM VH showed a 95% homology with a previously sequenced VHIV germline gene, VH4.21. Use of minimally modified VH genes and demonstration of reactivity with chronically present antigens (ie, actin, HIV-1 gp 160, or human IgG) suggests that B cells in HIV-1-infected individuals proliferating in response to chronic antigenic stimulation may be at increased risk for lymphomagenesis.

Amino Acid Sequence↗
PubMed1994

Development of clinical disease in cats experimentally infected with feline immunodeficiency virus.

Cats naturally infected with feline immunodeficiency virus (FIV) develop an AIDS-like syndrome whereas experimentally infected cats do not. To investigate the role of cofactors in the development of this disease in cats, 7 specific pathogen-free (SPF) and 12 random-source (RS) cats were infected with FIV. Over 4 years, infected cats developed similar phenotypic and functional immune abnormalities characterized by early and chronic inversion of CD4+:CD8+ cell ratios and significantly decreased mitogen responses compared with controls. Beginning 18-24 months after infection, 10 RS cats developed chronic clinical disease typical of feline AIDS, including stomatitis and recurrent upper respiratory disease; 4 SPF cats also developed chronic clinical disease, 2 with neurologic disease and 2 with B cell lymphomas. Thus, immunologic background is important in the type of disease that develops in cats infected with FIV, and FIV represents a promising animal model for studying the immunopathogenesis of AIDS in humans.

Animals↗
PubMed1992

Hypereosinophilia associated with transitional cell carcinoma in a cat.

A 14-year-old spayed female domestic shorthair cat was evaluated because of an abdominal mass and eosinophilia. Widely disseminated, transitional cell carcinoma of the urinary bladder was diagnosed histologically. To further characterize the eosinophilia, eosinophils were separated from other leukocytes and cultured in vitro. Harvested cells were evaluated for density and for in vitro survivability. Results of these tests, hyperplasia of bone marrow eosinophil precursors, and lack of tumor tissue eosinophilic infiltrates suggested that an eosinophilopoietic stimulus of undetermined origin was likely the cause of this cat's hypereosinophilia.

Animals↗
PubMed1992

Embryonic retinal ablation and post-metamorphic optic nerve crush: effects upon the pattern of regenerated retinotectal connections.

We examined relationships between healing observed during embryonic Xenopus retinal and optic nerve regeneration and resultant visuotectal pattern formation. Dorsal (D) and nasoventral (NV) 1/3 sized eye fragments were surgically created in stage 32 Xenopus laevis embryos. Gross anatomical healing modes of these fragments were examined 2 days post-surgery (stage 43). Healing was categorized according to the degree of cell movements observed. Animals were reared through metamorphosis and electrophysiologic mapping techniques were employed on those animals whose eyes regenerated. All D 1/3 fragments showed normal (non-duplicated) projections to the tectum; most (80%) of the healing observed showed little cell movements (the remaining 20% showed substantial cell movements, yet failed to show duplicated projections). Most NV 1/3 fragments (73%) formed two mirror image projections to the contralateral midbrain optic tectum (pattern duplication). Most (88%) of the healing observed among these animals showed massive cell movements in the ventral retinal region (the remaining 12% showed moderate cell movements). The remaining NV 1/3 fragments (27%) showed moderate cell displacement and failed to show duplicated projections). These data are compatible with a cell-movement:intercalary cell division hypothesis in which duplication is dependent upon specific positional confrontation and subsequent cell division. In additional studies, in adult animals, the optic nerves of eyes with duplicated projections were crushed and allowed to regenerate for 1 year. Duplicated projections were restored, indicating that developmental and maturational factors are probably not responsible for duplicative pattern formation; rather, information intrinsic to the eye, possibly created during healing interactions and/or fiber ingrowth to the tectum, underlies duplicate innervation of the tectum.

Animals↗