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Biomedical subjects

J Bean

Publications and source records attributed to J Bean.

At least 37 records · Page 2Linked to original sources
PubMed1994

Parkinson's disease and brain levels of organochlorine pesticides.

Epidemiological studies have suggested an etiologic relationship between pesticide exposure and Parkinson's disease (PD). Organochlorine pesticides were assayed in postmortem brain samples from 20 PD, 7 Alzheimer's disease (AD), and 14 nonneurological control cases. The three groups were similar in age at death, sex, and demographic variables. Only two of 16 pesticide residues screened were detected. A long-lasting residue of DDT (pp-DDE) was found in the majority of cases of PD and AD, as well as in all the control cases; pp-DDT was significantly more likely to be found in AD controls than the PD cases (Fisher's exact two-tailed, p = 0.04). Dieldrin was detected in 6 of 20 PD brains, 1 of 7 AD, and in none of 14 control samples. Despite the relatively small number of brains assayed, the association between Dieldrin and the diagnosis of PD was highly significant (p = 0.03). Dieldrin, a lipid-soluble, long-lasting mitochondrial poison, should be investigated as a potential etiological agent of Parkinsonism.

Age Factors↗
PubMed1993

Design of a device to exercise hip extensor muscles in children with cerebral palsy.

Children with cerebral palsy (CP) often have weak hip extensor muscles and gait-related difficulties. Current therapeutic techniques do not provide sufficient exercise for this muscle group. In addition to calisthenics, therapists use a traditional tricycle to strengthen leg muscles, yet the mechanics of traditional tricycles are not effective in exercising hip extensor muscles. A new therapeutic tricycle was designed specifically to exercise the hip extensor muscles, and tests compared the traditional tricycle to the new hip extensor tricycle in effectiveness of promoting hip extensor activity in two subjects without CP. The tests demonstrated that the hip extensor tricycle was more effective in promoting hip extensor activity. Tests are underway to investigate the effect of the hip extensor tricycle in improving hip extensor strength and gait in patients with cerebral palsy. This paper describes the design of the hip extensor tricycle and a preliminary investigation of its effectiveness.

Cerebral Palsy↗
PubMed1991

Rectal irrigation with short-chain fatty acids for distal ulcerative colitis. Preliminary report.

Colon cells from patients with ulcerative colitis utilize short-chain fatty acids inefficiently and may be exposed to decreased concentrations of these compounds. To test whether irrigation of the inflamed mucosa with short-chain fatty acids is useful, we conducted a six-week preliminary trial in 12 patients with distal colitis. Each patient used twice daily rectal irrigations with 100 ml of a solution containing acetate (80 mM), propionate (30 mM), and butyrate (40 mM). Two patients stopped at three weeks, one because of no improvement and the other because of complete resolution of symptoms. Of the 10 who completed the trial, nine were judged to be at least much improved and showed a change in a mean disease activity index score from 7.9 +/- 0.3 (SE) to 1.8 +/- 0.6 (SE) (P less than or equal to 0.002) and in a mucosal histology score from 7.7 +/- 0.7 (SE) to 2.6 +/- 0.7 (SE) (P less than or equal to 0.002). Thus, ulcerative colitis patients appear to benefit from increased contact with or higher than usual levels of these critical energy substrates.

Acetates↗
PubMed1991

Invasive cutaneous melanoma in elderly patients.

Clinical and pathologic variables were compared between "older" (greater than or equal to 70 years) and "younger" (30 to 39 years) patients with primary invasive cutaneous melanoma. Older patients had more nodular melanomas and acral lentiginous melanomas (58%); superficial spreading melanomas predominated in younger patients (74%). Mean tumor thickness was greater in the older patients (3.95 vs 2.02 mm). Invasive levels 2 and 3 occurred more often in younger patients (41.1% vs 13%); level 5 occurred more often in older patients (30.4% vs 5.3%). Microscopic ulceration occurred more often in older (46.4%) than in younger patients (19.4%). Older patients classified as clinical stage I at presentation or with primary lesions 1.50- to 3.00-mm thick had poorer survival. Younger women survived longer than younger men; this was not true of older patients. The elderly patients with cutaneous melanoma were more likely to have poor prognostic features and thus more likely to die from melanoma than the younger patients.

Adult↗
PubMed1990

5,5-Dimethylthiazolidine-4-carboxylic acid (DTC) as a proline analog with restricted conformation.

Spectroscopic evidence is presented for the lack of intramolecular hydrogen bonding in a simple peptide derivative of 5,5-dimethylthiazolidine-4-carboxylic acid (Dtc). The infrared spectrum of Boc-Pro-Ile-OMe 1 in nonpolar solvents displays two N-H stretching bands at 3419 and 3330 cm-1 in CCl4 and one at 3417 and 3328 cm-1 in CHCl3. The low frequency band at 3328-3330 cm-1 may be assigned to conformations with an intramolecular hydrogen bond between the Ile N-H and Boc C = O. The band at 3417-3419 cm-1 is the normal Ile N-H stretch. In the polar solvent CH3CN only one NH stretching band at 3365 cm-1 is observed. The IR spectrum of Boc-Dtc-Ile-OMe 2, on the other hand, displays one N-H stretching band at 3423 cm-1 in CCl4 and one at 3418 cm-1 in CHCl3. The IR spectrum of 2 does not display the N-H stretching band that would arise from intramolecular hydrogen bonding between the Boc C = O and Ile N-H. The lack of intramolecular hydrogen bonding for Boc-Dtc-Ile-OMe 2 was evident also in the NMR spectra in nonpolar solvents. The 1H-NMR spectrum of the Pro dipeptide 1 in 50% CDCl3/C6D6 at 20 degrees displayed two Ile-NH signals at 6.58 and 7.74 ppm. The latter signal corresponds to the intramolecularly hydrogen bonded Ile-NH in the trans-Boc isomer of 1 (60% of the total population), while the former signal corresponds to the nonhydrogen bonded Ile-NH in the cis-Boc isomer.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1989

Methods for the reduction of AIDS social anxiety and social stigma.

A cognitive-social model is proposed for the study of AIDS social attitudes. Features of the ambivalent (fear and compassion) public belief system toward PWAs are outlined and ways to increase altruism and reduce fear are specified. Three studies are reported using cognitive-social methods for the reduction of AIDS social anxiety and social stigma. Study 1 found that cognitive inoculation and abbreviated group desensitization equally reduced AIDS social anxiety measured by a verbal scale. One form of brief group desensitization was superior to basic factual, counterphobic inoculation in reducing desire for social restriction of persons with AIDS (PWAs). In Study 2 subject improvisational role playing of PWAs increased positive attitudes toward PWAs and desire for altruistic actions but did not reduce measured fear. Knowledge of AIDS was negatively correlated with AIDS social anxiety and desire for patient restriction. AIDS social anxiety was negatively correlated with altruism and positively correlated with homophobia. In Study 3, three forms of experimenter-guided mastery imagery reduced AIDS social anxiety and increased AIDS altruism. Results of these studies may have relevance to reducing high-risk contagious behavior, as well as to reducing AIDS social stigma and social anxiety. A componential model of AIDS education is described.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Estrogen use and breast cancer. Interaction with body mass.

With few exceptions, most epidemiologic studies do not show an excess relative risk of breast cancer associated with menopausal estrogen therapy. Other studies show a relationship of breast cancer to obesity, which is characterized by increased endogenous estrogen production. This study explored the possibility of an interaction between ponderosity and exogenous estrogen use in a case-control study of 113 postmenopausal breast cancer patients and pair-matched hospital control subjects. In this series, neither menopausal estrogen use nor relative weight were significantly associated with breast cancer risk. However, among estrogen users, the relative risk of breast cancer was strikingly influenced by the ponderosity of the subjects; the relative risk was 0.41 for women whose relative weight was less than the median, compared with 1.29 for those whose relative weight exceeded the median. The mean age was also examined at diagnosis in order to explore the potential of exogenous estrogen as a tumor promotor. The mean age at breast cancer diagnosis in estrogen users, 58.1 years, was significantly lower than in nonusers, 63 years. A significant linear relationship was found between age at diagnosis and body weight among estrogen users. Estrogen-treated women in the lowest tertile of body weight had the diagnosis of breast cancer made seven years earlier than those in the highest tertile of weight. There was no significant difference in the distribution of clinical stages at diagnosis between estrogen users and nonusers. These data suggest that relative body weight is an important modifier of the effect of exogenous estrogens on breast cancer biology.

Age Factors↗
PubMed1982

Interstitial 252Cf neutron therapy for glioblastoma multiforme.

252Cf brachytherapy has been combined with whole brain photon beam therapy to 6000 rads in 5-7 weeks. In early phase I studies, all patients selected for study tolerated the procedure and the subsequent photon beam therapy. All showed improvement in performance status and decreased tumor size by CT scan evaluation, but it became clear that these tumors are of large size and bulk, produce marked adjacent brain edema, and require individualized implant therapy as well as high-dose external beam irradiation if response is to occur.

Brachytherapy↗
PubMed1982

Work in progress: 252Cf neutron brachytherapy for hemispheric malignant glioma.

It has been shown that 252Cf neutron brachytherapy of hemispheric malignant glioma can be readily carried out and may be combined with external, whole brain photon beam therapy of 6,000 rad (60 Gy) administered over a five-week to seven-week period. The ten patients who were studied tolerated both procedures well. There was improvement in performance status, and a decrease in tumor size was observed upon computed tomographic scanning.

Aged↗
PubMed1981

Relationship of body weight to menarcheal and menopausal age: implications for breast cancer risk.

Early menarche and late menopause are risk factors for the development of breast cancer. An adequate hormonal mechanism for those observations has not been described. Because obesity has also been associated with increased breast cancer risk, we examined the relationship among height, weight, adiposity, and menstrual cycle characteristics in women who prospectively recorded menstrual cycle intervals and reproductive events as part of the Menstrual and Reproductive History Research Program. Within this study cohort, adult height, weight, and a derived index of adiposity were related to both earlier age at menarche and later age at menopause. The association of early age at menarche with adiposity persisted from age 18 yr through middle age and into the menopausal years. There was no relationship between body mass and age at first pregnancy, another breast cancer risk factor. Women who were heavier at 18 yr of age and thereafter gained 5 lb or more had significantly greater mean menstrual cycle length and variability during the 7-yr period after menarche than the other members of the cohort. There was no obvious relationship between weight indices and menstrual cycle pattern during mature reproductive life or during the 7 yr before menopause. Our data suggest that menarcheal and menopausal age may have a common relationship to nutritional status and to constitutional features that predate the onset of menarche and persist into later life.

Adipose Tissue↗
PubMed1980

The effect of hemodilution on experimental myocardial infarct size.

Hemodilution is used frequently for patients undergoing elective coronary bypass surgery but relatively little is known about the effects of hemodilution on acute myocardial infarction. Left ventricular infarctions were planimetered after acute coronary occlusion in dogs treated with and without hemodilution. The control group was maintained at a normal hematocrit (40-45) while the intervention group was hemodiluted with 6% dextran in saline 30 min after left anterior descending coronary artery occlusion to a hematocrit less than 50% of control (20). Systemic arterial and left atrial pressure were maintained at control levels as were arterial pO2 and pH. Mean infarct size in the control group was 20.72 +/- 1.38% (SEM) of the left ventricle while the hemodiluted group had a mean infarct size of 18.80 +/- 2.11% of the left ventricle. Reduction of red cell mass to less than 50% of normal does not increase the size of myocardial infarction after acute coronary artery occlusion suggesting that oxygen supply to ischemic areas is maintained if systemic hypoxia is prevented.

Animals↗