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Biomedical subjects

J L Carter

Publications and source records attributed to J L Carter.

At least 19 recordsLinked to original sources
PubMed2002

The effect of diet fed to lambs on subsequent development of Trichostrongylus colubriformis larvae in vitro and on pasture.

Contrasting herbage diets were fed to lambs to evaluate their effect on subsequent development of Trichostrongylus colubriformis larvae in faeces and on pasture. The diets had either no condensed tannin (CT), lucerne (Medicago sativa cv. Otaio), white clover (Trifolium repens cv. Tahora), or had moderate to high concentrations of CT, sulla (Hedysarum coronarium cv. Grassland Aokau), Lotus corniculatus (cv. Grasslands Goldie), L. pedunculatus (cv. Grassland Maku), Dorycnium pentophyllum, and Dorycnium rectum. Trials were carried out in summer (warm) and in autumn (cool and moist). In summer, egg viability was evaluated in vitro with egg hatch and larval development assays. In both seasons faeces were placed on pasture to compare recovery of eggs and larvae from faeces and larvae from herbage on the high and low fertility farmlets on the AgResearch Ballantrae Hill Country Research Station. D. rectum and D. pentophyllum diets decreased (P<0.01) egg hatching and larval development in laboratory assays relative to other diets. In summer, the number of larvae recovered from faeces placed on pasture was far greater (P<0.001) if the lambs had been fed lucerne than any other diet, whereas recovery was always lowest from faeces of sheep fed D. rectum and D. pentophyllum. Although dietary differences were lower in autumn than in summer, larval recoveries were lower (P<0.05) from faeces of lambs fed D. rectum and L. corniculatus than from white clover, lucerne and sulla diets. This study indicates that the diet of the host can have a significant impact on egg hatching and the subsequent development of T. colubriformis larvae in the laboratory and in the field. In particular, D. rectum consistently reduced T. colubriformis development. Effects measured in vitro generally under-estimated effects measured under field conditions.

Animal Feed↗
PubMed2001

Effect of mutations in Pneumocystis carinii dihydropteroate synthase gene on outcome of P carinii pneumonia in patients with HIV-1: a prospective study.

BACKGROUND: Investigators have reported that patients infected with Pneumocystis carinii containing mutations in the DHPS (dihydropteroate synthase) gene have a worse outcome than those infected with P carinii containing wild-type DHPS. We investigated patients with HIV-1 infection and P carinii pneumonia to determine if DHPS mutations were associated with poor outcomes in these patients. METHODS: We compared presence of mutations at the DHPS locus with survival and response of patients to co-trimoxazole or other drugs. FINDINGS: For patients initially given co-trimoxazole, nine (14%) of 66 with DHPS mutant died, compared with nine (25%) of 36 with wild type (risk ratio50.55 [95% CI=0.24-1.25]; p=0.15). Ten (15%) of 66 patients with a DHPS mutant did not respond to treatment, compared with 13 (36%) of 36 patients with the wild type (0.42 [0.20-0.86]; p=0.02). For patients aged 40 years or older, four (14%) of 29 with the mutant and nine (56%) of 16 with the wild type died (0.25 [0.09-0.67]; p=0.005). INTERPRETATION: These results, by contrast with those of previous studies, suggest that patients with wild-type P carinii do not have a better outcome than patients with the mutant when given co-trimoxazole. Our results suggest that presence of a DHPS mutation should be only one of several criteria guiding the choice of initial drug treatment of P carinii pneumonia in patients with HIV-1 infection.

AIDS-Related Opportunistic Infections↗
PubMed2001

Metachronous bilateral primary adenocarcinoma of the submandibular glands.

A young woman developed an unusual adenocarcinoma in each submandibular salivary gland at an interval of 30 months. This presentation has not been described previously. The possible etiology for this and treatment options are discussed. The choice of diagnostic imaging (ultrasound versus magnetic resonance imaging) is highlighted. As a result of regular follow-ups using diagnostic ultrasound, a second tumor was observed to reach a dimension of 8 mm in less than 6 months. This is probably the first report documenting the extent of initial growth of this rare tumor.

Adenocarcinoma↗
PubMed2001

Ultrasound features of osteosarcoma of the mandible--a first report.

Ultrasound imaging is becoming widely used in the head and neck region as a first-line investigation to assess soft tissue swellings. Clinicians should be aware of the potential of diagnostic ultrasound to identify important signs of malignant disease involving bone. Involvement of the mandible by osteosarcoma is uncommon. A young adult patient presented with facial swelling and an apparently infected lower third molar extraction socket. Subtle signs were missed on dental radiographs. Diagnostic ultrasound investigation was pivotal in identifying sinister signs: namely, soft tissue mass associated with bone thinning, erosion, expansion, and the "sunray" appearance of the buccal cortex, which were suggestive of osteosarcoma. These findings enabled priority to be given to subsequent investigations using other modalities. We present a first report of the ultrasound features of osteosarcoma of the mandible and consider this to be a useful modality in an initial investigation.

Adult↗
PubMed2000

Sulfa or sulfone prophylaxis and geographic region predict mutations in the Pneumocystis carinii dihydropteroate synthase gene.

To determine factors associated with mutations in the Pneumocystis carinii dihydropteroate synthase (DHPS) gene, a prospective study of human immunodeficiency virus (HIV)-infected patients with confirmed P. carinii pneumonia was conducted in Atlanta, Seattle, and San Francisco. Clinical information was obtained from patient interview and chart abstraction. DHPS genotype was determined from DNA sequencing. Overall, 76 (68.5%) of 111 patients had a mutant DHPS genotype, including 22 (81.5%) of 27 patients from San Francisco. In multivariate analysis, sulfa or sulfone prophylaxis and study site were independent predictors of a mutant genotype. Fourteen (53.8%) of 26 patients who were newly diagnosed with HIV infection and had never taken prophylaxis had a mutant genotype. The significance of geographic location as a risk factor for mutant genotype and the high proportion of mutant genotypes among persons never prescribed prophylaxis, including those newly diagnosed with HIV infection, provide indirect evidence that these mutations are transmitted from person to person either directly or through a common environmental source.

AIDS-Related Opportunistic Infections↗
PubMed2000

VMN hypothalamic dopamine and serotonin in anorectic septic rats.

During sepsis, catabolism of proteins and associated changes in plasma amino acids occur. Tryptophan and tyrosine, and their derivatives serotonin (5-HT) and dopamine (DA), influence hypothalamic feeding-related areas and are associated with the onset of anorexia. We hypothesized that anorexia of sepsis is associated with changes in serotonin and dopamine in the ventromedial nucleus (VMN) of the hypothalamus. The aim of this study was to test our hypothesis by measuring intra-VMN changes of these two neurotransmitters at the onset of anorexia during sepsis. Fischer 344 male rats had an intracerebral guide cannula stereotaxically implanted into the VMN. Ten days later, in awake, overnight-food-deprived rats, a microdialysis probe was inserted through the in situ VMN cannula. Two hours thereafter, serial baseline serotonin and dopamine concentrations were measured. Then cecal ligation and puncture to induce sepsis or a control laparotomy was performed under isoflurane anesthesia. VMN microdialysis samples were serially collected every 30 min for 8 h after the surgical procedure to determine 5-HT and DA changes in response to sepsis. During the hypermetabolic response to sepsis, a strong association occurred between anorexia and a significant reduction of VMN dopamine concentration (P < 0.05; constant rate of dopamine decrease in the Study group of 0.99 pg per 2 h); no changes occurred in 5-HT in association with anorexia of sepsis. Six hours after operation, a single meal was offered for 20 min to assess the response of neurotransmitters to food ingestion. Food intake was minimal in anorectic septic rats (mean size of the after food-deprived meal in the Septic group was 0.03+/-0.01 g, that of the Control group was 1.27+/-0.14 g; P = 0.0001), while Control rats demonstrated anticipated changes in neurotransmitters in response to eating. We conclude that the onset of anorexia in septic rats is associated with a reduction in VMN dopamine.

Animals↗
PubMed2000

Activity of ABT-773 against Mycobacterium avium complex in the beige mouse model.

ABT-773, a new ketolide antimicrobial agent, was evaluated in comparison to clarithromycin (CLA) in vitro against Mycobacterium avium complex (MAC) and in a beige mouse model of disseminated MAC infection. The MICs at which 50 and 90% of the isolates tested were inhibited were 2 and 4 microg/ml, respectively, for CLA and 8 and 16 microg/ml, respectively, for ABT-773. Eight CLA-resistant isolates were found to be resistant to ABT-773 (MICs > 64 microg/ml). In the in vivo study mice were treated with ABT-773 (50, 100, and 200 mg/kg of body weight) or CLA (200 mg/kg). Both ABT-773 (100 and 200 mg/kg) and CLA significantly decreased the viable cell counts in spleens and lungs. ABT-773 (200 mg/kg) and CLA had similar activities in lungs, but the former was more active in spleens.

Animals↗
PubMed2000

Nursing considerations in support of a patient pursuing his dream.

A 30-year-old man with end stage renal disease (ESRD) undergoing thrice weekly hemodialysis set out to achieve a personal goal to ride his bicycle across the United States within 30 days. To support patients in achieving such a goal, nephrology nurses must consider not only nutritional components, but must be prepared to deal with the physical challenges that face patients in the daily struggles struggle to reach their goal. It became a priority and a challenge for the nephrology team to treat this young man as an athlete who also happened to have ESRD, rather than as a dialysis patient who was a cyclist.

Adult↗
PubMed1999

Therapy of relapsing multiple sclerosis. Treatment approaches for nonresponders.

There is increasing impetus to begin disease-modifying therapy for relapsing multiple (R-MS) early, before the development of irreversible tissue damage and resultant permanent disability. However, all of the currently-approved therapies for relapsing multiple sclerosis are only partially effective for patients as a group. Treatment failure can be due to noncompliance with therapy, intolerable adverse effects, the development of neutralizing antibodies, or non-responsive disease. Neurologists managing patients on disease-modifying therapy for R-MS must remain vigilant for these issues and take appropriate action when necessary.

Anti-Inflammatory Agents↗
PubMed1999

Use of recombinant human soluble TNF receptor in anorectic tumor-bearing rats.

With progression of tumor growth, rats demonstrate anorexia and reduced food intake, a function of meal number and meal size. Tumor necrosis factor-alpha (TNF-alpha), a recognized anorectic agent, reacts with two different receptors (type I: 55 kDa; type II: 75 kDa). We used a dimeric, pegylated 55-kDa TNF receptor construct to test its effects on food intake, meal number, and meal size, which were continuously measured with a rat eater meter in 16 Fischer 344 male rats injected with 10(6) viable methylcholanthrene cells. When anorexia developed, rats received a subcutaneous injection of either 0.25 mg/kg body wt of soluble TNF receptor construct (study) or vehicle (tumor-bearing control). Before TNF inhibitor injection, no differences were observed in food intake, meal number, or meal size between the two groups. After the TNF inhibitor injection, study vs. control rats significantly improved food intake as a result of an increase in meal number and meal size. Rats also showed a significant improvement in body weight. These data suggest that TNF-alpha, in addition to other cytokines, contributes to the anorexia of tumor growth, probably mediated via the hypothalamus.

Animals↗
PubMed1997

Rational clinical immunotherapy for multiple sclerosis.

In this article, we assess the roles and the efficacy of immunopharmacologic agents in the treatment of multiple sclerosis (MS) and other demyelinating disease syndromes. The initial clinical manifestations of demyelinating disease, immunotherapeutic goals, efficacy of individual agents, and specific immunopharmacologic recommendations are discussed. MS and other idiopathic demyelinating disease syndromes can be effectively managed with immunotherapy. Exacerbations are treatable, and the frequency and severity of exacerbations can be reduced. Although some agents have a minor effect on progression of disability, current approaches have not proved to have a major influence on treatment of progressive MS. Immunotherapy for inflammatory demyelinating disease necessitates a high degree of clinical certainty about the diagnosis. Because all available therapeutic agents have limitations and significant toxic effects, careful consideration is necessary before use. Treatment should be individualized on the basis of the clinical course of the disease and the degree of patient disability.

Acute Disease↗
PubMed1997

Management of impairment, disability, and handicap due to multiple sclerosis.

In this article, we update management measures for patients with multiple sclerosis (MS) that can improve or prevent impairment, disability, and handicap and include those factors that a primary-care physician can implement or facilitate. The medical literature since 1989 was reviewed. Although new drug trials hold promise to decrease impairment from MS, well-coordinated interdisciplinary care to minimize disability and handicap most profoundly affect the quality of life for patients with MS. MS is usually not severely disabling, and appropriately timed intervention can prevent secondary impairment and reduce disability and handicap. Pharmacologic, physical, and psychosocial issues--ranging from spasticity, pain, weakness, and tremor to neurogenic bowel management and sexuality--are addressed. General wellness measures remain important. The influence of the Americans With Disabilities Act is discussed, and specific adaptive equipment and social resources are outlined. The ultimate goals of management of patients with MS are functional independence and efficient use of medical and community resources: a focus on "ability" rather than "disability." Although impairment can limit function, wellness and adjustment have no boundaries.

Activities of Daily Living↗