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Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 793 records · Page 44Linked to original sources
PubMed1989

Coexisting dementia and depression in Parkinson's disease.

Dementia and depression in patients with Parkinson's disease have been reported separately, but their prevalence is controversial. This study examines the coexistence of these two problems and suggests a common underlying biochemical system. We examined these two entities by retrospective chart review and cerebrospinal fluid biochemistry. We found a prevalence of 10.9% for dementia, 51% for depression, and 5.4% for coincident depression and dementia. In a prospective study of patients with Parkinson's disease we found a continuum of cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations. Patients who were either depressed or demented had lower concentrations of this metabolite than other patients with Parkinson's disease, but patients who were depressed and demented had the lowest levels. These results suggest that the coexistence of dementia and depression represents a unique clinical entity in Parkinson's disease. The serotonergic system may be involved in depression and dementia because evidence of a cumulative effect on this biochemical system is present.

Aged↗
PubMed1989

Overproduction of the regulatory subunit of the cAMP-dependent protein kinase blocks the differentiation of Dictyostelium discoideum.

During the aggregation of Dictyostelium discoideum extracellular cAMP is known to act as a chemotractant and as an inducer of cellular differentiation. However, its intracellular role as a second messenger remains obscure. We have constructed a fusion gene consisting of the cDNA encoding the regulatory subunit (R) of the cAMP-dependent protein kinase fused to the promoter and N-terminal-proximal sequences of a Dictyostelium actin gene. Stable transformants, containing multiple copies of this gene, overproduce the R subunit which accumulates prematurely relative to the endogenous protein. These transformants fail to aggregate. Detailed analysis has shown that they are blocked at interphase, the period prior to aggregation, and that they are severely defective in most responses to cAMP including the induction of gene expression. Our observations suggest that intracellular cAMP acts, presumably by activation of the catalytic subunit of the cAMP-dependent protein kinase, to facilitate early development.

Blotting, Western↗
PubMed1989

Toxic hydrolysis product from a biodegradable foam implant.

A commercially available mammary implant containing a soft polyester polyurethane foam shell has been examined for possible diamine hydrolysis products. Fourier Transform Infrared (FT-IR) analysis has shown ester and aromatic structures present in the intact foam shell. Vigorous hydrolysis conditions using NaOH have produced a mixture with large amounts of toluene diamine (TDA) present as determined by Gas Chromatography-Mass Spectrometry (GC/MS), and GC/FT-IR. There are numerous clinical reports of the degradation of this implant shell after implantation with incorporation of fragments into phagocytic cells at the implantation site. Recent reports have discussed late pain and other allergic reactions to this implant. Release of the known toxic material, TDA, is consistent with these observations and strongly suggests that an alternative material be used in this application.

Biodegradation, Environmental↗
PubMed1989

Dopamine and memory function in Parkinson's disease.

Response fluctuations in motor function, complicating long-term dopaminomimetic therapy of Parkinson's disease, may extend to the cognitive realm. To evaluate the effect of levodopa treatment both on attention as well as acquisition and retrieval of memory tasks, parkinsonian patients were examined neuropsychologically both while medicated with levodopa/carbidopa ("on") and when the medication's antiparkinsonian effect had worn off ("off"). Significant cognitive differences emerged only on the delayed recall of complex verbal materials, where patients when "on" performed better compared with their "off" state. Comparison of change scores across states (administration or withholding of levodopa/carbidopa between acquisition and retrieval, "off" to "on" or "on" to "off"), revealed no substantial differences as a function of dopaminomimetic therapy. These results support the view that slight changes in cognition are associated with dopaminomimetic therapy of Parkinson's disease, but that these changes may be task-specific.

Aged↗
PubMed1989

Estradiol and chlordecone interactions with the estradiol receptor.

The in vivo and in vitro effects of the chlorinated pesticide, chlordecone, on the estradiol receptor of adult ovariectomized CDF-344 rats were examined. Chlordecone's competition with [3H]estradiol for binding to the estradiol receptor in vitro was similar whether receptors were derived from neural or uterine tissue. In vivo, chlordecone led to nuclear retention of estradiol receptors in both tissues, but in comparison to estradiol, the latency for such retention was slower following chlordecone. Nevertheless, chlordecone- and estradiol-treated animals eventually achieved the same degree of nuclear retention in uterine tissue. In brain, estradiol-like levels of nuclear retention were never found in chlordecone-treated females. Estradiol receptor replenishment following chlordecone or estradiol was similar in uterine tissue but not in brain. Chlordecone's lesser ability to mimic estradiol's receptor dynamics in the brain may contribute to the apparent tissue differences in chlordecone's estrogenicity.

Animals↗
PubMed1989

Serotonin binding sites during proestrus and following estradiol treatment.

The binding of 3H-5-HT to hypothalamic, hippocampal and striatal membranes from female rats was examined. During the day of proestrus, there was a significant increase in binding from morning to evening. The increase reflected changes in both Kc and Bmax. Effects of estradiol were examined in ovariectomized rats, and changes in 3H-5-HT binding resulted from an increase in the Kd after estradiol treatment. These in vivo effects of estradiol were not seen when tissue was incubated in vitro with estradiol. However, the compound, polyvinylpyrrolidone, used in the in vitro incubation significantly increased the Kd for binding to 3H-5-HT and estradiol attenuated the increase. The potential significance of these changes to serotonin's modulation of reproductive function is discussed.

Animals↗
PubMed1989

Improvements in brachytherapy quality assurance.

Quality assurance (QA) for a busy brachytherapy service is a demanding task which requires the involvement of the entire brachytherapy team. This communication describes the QA program for brachytherapy procedures and source identification and inventory which is currently practiced at the Radiation Oncology Center, Mallinckrodt Institute of Radiology.

Brachytherapy↗
PubMed1989

The effects of 1,3-dinitrobenzene and mono-(2-ethylhexyl)phthalate on hormonally stimulated lactate and pyruvate production by rat Sertoli cell cultures.

Lactate and pyruvate production by rat Sertoli cell cultures was measured after treatment with two toxicants (1,3-dinitrobenzene, DNB; mono-(2-ethylhexyl)phthalate, MEHP) in the presence or absence of follicle-stimulating hormone (FSH) or dibutyryl-cAMP (dbcAMP). 1,3-DNB together with FSH or dbcAMP produced increases in media lactate and pyruvate concentrations significantly greater than those induced by individual treatments. MEHP in conjunction with either hormone also produced greater increases in lactate concentrations compared with separate additions. However, MEHP produced a significant diminution in the hormonal stimulation of pyruvate secretion. Thus, 1,3-DNB appears to act independently of these hormones in stimulating the secretion of both metabolic products, whereas MEHP interferes with the hormonal stimulation of pyruvate (but not lactate) production.

Animals↗
PubMed1989

Diestrous treatment with lindane disrupts the female rat reproductive cycle.

Regularly cycling, adult female rats were treated during diestrus with 10, 25, 33 or 50 mg/kg lindane or with 2.5 mg/kg picrotoxin. The effects of the treatments on estrous cyclicity and on sexual behavior were examined. Doses of lindane greater than or equal to 25 mg/kg significantly increased the length of the vaginal cycle. Sexual receptivity was reduced by doses greater than or equal to 33 mg/kg, but reduction of sexual receptivity appeared to be secondary to the elongation of the estrous cycle. Most females treated with 50 mg/kg lindane failed to exhibit vaginal proestus during the duration of the experiment (6-8 d following treatment). For the lower doses, vaginal proestrus occurred later than was predicted from the cyclic history but was usually accompanied by sexual receptivity. Although lindane is reported to inhibit the GABAergic system, its reproductive effects were not mimicked by diestrous treatment with picrotoxin.

Animals↗
PubMed1989

Sexual behavior of intact female rats after treatment with o,p'-DDT or p,p'-DDT.

Sexual behavior of adult, female rats was tested following treatment with o,p'-DDT or with p,p'-DDT during either diestrus or proestrus. Both chlorinated compounds decreased lordosis behavior, but o,p'-DDT did so only after treatment on diestrus. p,p'-DDT in contrast, decreased sexual behavior under all treatment conditions. o,p'-DDT may have altered behavior by disrupting the estrous cycle while p,p'-DDT had a major effect on the female's proceptivity and receptivity without modifying vaginal cyclicity. p,p'-DDT disrupted sexual behavior at doses as low as 25 mg/kg while 100 to 200 mg/kg o,p'-DDT were required. Since commercially prepared DDT contained a predominant proportion of p,p'-DDT, these results suggest that many reproductive effects of DDT may have resulted from p,p'-DDT rather than from o,p'-DDT.

Animals↗
PubMed1989

Disseminated ecthymatous herpes varicella-zoster virus infection in patients with acquired immunodeficiency syndrome.

Herpesvirus infections are among the most common and debilitating opportunistic infections in patients with acquired immunodeficiency syndrome (AIDS), and they may have atypical clinical features. We describe the cases of three patients with AIDS in whom atypical persistent ulcerative skin lesions developed as a result of varicella-zoster virus infection. Two patients had disseminated infection without a vesicular stage; one patient had underlying asteatotic eczema. All responded well to acyclovir. One patient was treated with azidothymidine, and typical dermatomal herpes zoster subsequently developed. The profound loss of helper T cell function in AIDS may lead to multiple abnormalities in local immune response to cutaneous herpesvirus infections and may be responsible for the atypical morphology and a prolonged course.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Comparison of five-view and three-view cervical spine series in the evaluation of patients with cervical trauma.

The three-view trauma series has been the standard screening examination for patients with cervical spine trauma. We conducted a prospective study to determine if the addition of supine oblique views to the three-view series would improve detection of fractures, subluxations, dislocations, or locked facets. All patients over a two-year period with suspected cervical spine injury had a five-view series obtained (three-view series and supine oblique views), and selected high-risk patients underwent thin-section conventional tomography of the cervical spine. Films were interpreted separately by two radiologists and an emergency physician, and the tomography results were used as the gold standard for comparison. Thirty-three of 58 high-risk patients had one or more fractures, subluxation, or dislocation demonstrated on tomography. There were no fractures or dislocations detected on the five-view series that were not detected or suspected on the three-view series. In areas of the cervical spine reported to be better visualized by supine oblique views than three-view series, our results indicate that supine oblique views did not improve detection but did, in certain cases, allow more specific diagnosis of injuries. Our data do not support the routine use of supine oblique views in the initial radiographic evaluation of patients with cervical spine trauma.

Adolescent↗
PubMed1989

Rural America. Unique opportunities for health care delivery and health services research.

A general deterioration is occurring in the quality of life of rural Americans, and it is affecting the quality of health and mental health service delivery. About 24% of the U.S. population lives in nonmetropolitan areas where the citizens are older, less well educated, have lower incomes, and are more homogeneous in terms of race and ethnicity. Medicare and private insurance discriminate against rural services in their reimbursement policies, and there is a shortage of health personnel in rural areas. However, there has been renewed congressional action to meet rural needs. Both the House and Senate have established rural caucuses, and an Office of Rural Health Policy has been established in the federal executive branch. Legislative successes were achieved between 1985 and 1988. Rural initiatives will provide psychology with unique opportunities in the next several years.

Delivery of Health Care↗
PubMed1989

A specialist leukaemia/lymphoma registry in the UK. Part 1: Incidence and geographical distribution of Hodgkin's disease. Leukaemia Research Fund Data Collection Study Group.

This paper describes the epidemiology of Hodgkin's disease occurring in parts of the United Kingdom between 1984 and 1986. The cases were carefully diagnosed and the data rigorously cross-checked as part of the larger Leukaemia Research Fund Data Collection Survey of all lymphoid and haematogenous malignancies. The age-specific rates show the lack of an older adult second peak. Spatial variation is examined in some detail. At county and district levels there is little heterogeneity in the distribution of cases. However, at the electoral ward level there were real differences for the younger age group (0-34).

Adolescent↗
PubMed1989

A specialist leukaemia/lymphoma registry in the UK. Part 2: Clustering of Hodgkin's disease.

Part 1 describes the epidemiology of Hodgkin's disease occurring in those parts of the United Kingdom which are included in the Leukaemia Research Fund data collection survey. A total of 1,023 cases diagnosed between 1984 and 1986 were available for analysis. At county and district levels there was little heterogeneity in the distribution of cases. However, at the electoral ward level there were real differences for the younger age group (0-34). In this paper methods of investigation which are not dependent on census boundaries are applied and the presence of localised spatial clustering is confirmed. There is some evidence that the pattern of clustering relates to the nodular sclerosing subtype. These results are related to hypotheses of an infectious aetiology.

Adolescent↗