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Biomedical subjects

R L Parker

Publications and source records attributed to R L Parker.

At least 19 recordsLinked to original sources

Different forms of childhood abuse and memory.

Recently a heated controversy emerged regarding recovered memories of childhood sexual abuse, but the prevalence and nature of these memories as well as the relationship between a history of child abuse and childhood memory generally have received limited empirical examination. This study (N = 429 nonclinical participants) found that similar proportions of those reporting histories of sexual, emotional, and physical abuse reported that they had periods without memory for their abuse (19.8%, 11.5%, and 14.9%, respectively). These participants, however, appeared to be referring to both a lack of conscious access to their abuse memories as well as the intentional avoidance of the memories for some period. There was a great deal of variance found in the reported quality of general childhood memory, but this was unrelated to reporting a history of child abuse. In addition, it appears to be normative to recover previously forgotten childhood events, and this too was found to be unrelated to history of child abuse.

Adolescent↗

Expression and alternative processing of a chicken gene encoding both growth hormone-releasing hormone and pituitary adenylate cyclase-activating polypeptide.

The chicken growth hormone-releasing hormone (GRF) gene was isolated, sequenced, and characterized. In addition, three different mRNAs were isolated from juvenile and adult brain. The first cDNA encoded for a GRF(1-46), the second cDNA encoded for a GRF(1-43) due to a sliding intron boundary, and the third skipped exon four and encoded only GRF(33-46). We also determined that juvenile chicken mRNA encoding GRF is expressed in the brain and gonads, but not in the pituitary, heart, liver, kidney, crop, small intestine, large intestine, eye, and muscle. This gene is also interesting in terms of evolution because another neuropeptide, pituitary adenylate cyclase-activating polypeptide (PACAP), is encoded within the same gene (grf/pacap) in chicken, but on a separate gene (pacap) in mammals. We showed previously that these two neuropeptides were encoded in the same cDNA in fish, but the present evidence in chicken suggests a gene duplication in stem mammals.

Alternative Splicing↗

Intrathecal neostigmine for post-cesarean section analgesia: dose response.

Intrathecal (IT) neostigmine produces analgesia in animals and humans and enhances systemic opioid analgesia. To examine the safety of IT neostigmine for eventual use in obstetrics, we studied 24 healthy, term pregnant patients scheduled to receive elective cesarean section using a combined spinal-epidural anesthetic. Using an open-label, dose-ranging design, patients received either IT placebo or neostigmine 10, 30, or 100 microg in a 1-mL solution of 5% glucose in normal saline followed in 15 min by 2% epidural lidocaine for cesarean section. Neostigmine did not affect fetal heart rate tracings or Apgar scores. The women received patient-controlled analgesia intravenous morphine postoperatively. Compared with the glucose control, neostigmine produced a dose-independent reduction in postoperative morphine use. Cumulative average 24-h morphine use was 82 +/- 7 mg for women receiving IT placebo and 50 +/- 8 mg for women receiving IT neostigmine (P < 0.003). Hourly morphine use was significantly reduced in the neostigmine groups for 10 h postoperatively. These data indicate that IT neostigmine can produce 10 h of post-cesarean section analgesia without adverse fetal effects and support cautious further prospective study.

Adult↗

Macrophage-tumor cell associations: a factor in metastasis of breast cancer?

In human breast carcinomas tumor cells and macrophages are often proximal. We previously reported on the relationship between tumor cell growth and macrophage concentration and report here on the possible involvement of macrophages in the metastatic process. We hypothesize that during the initial stages of metastasis, tumor cells are likely to encounter macrophages and form aggregates. Using a cell culture method that encourages cellular interactions, we found aggregates involving macrophages. Macrophages partly or completely surround other cell types without any apparent ill effect. Units involving macrophages and tumor cells would possess many properties necessary for invasion, which is a normal process for macrophages. Properties such as motility and production of specific enzymes necessary to traverse the extracellular matrix, basement membrane, and endothelial cell barriers may provide an advantage for tumor cells. Physical support and protection from immune recognition during transport of the tumor cell through the vascular system may also be enhanced, and paracrine growth stimulation and angiogenic activity may be provided at the new metastatic site. Verification of these observations in vivo could lead to new directions for limiting breast cancer metastasis.

Breast Neoplasms↗

Epidemiologic characteristics of human tularemia in the southwest-central states, 1981-1987.

From 1981 through 1987, a total of 1,041 cases of tularemia in humans were reported in Arkansas, Kansas, Louisiana, Missouri, Oklahoma, and Texas; this represents 60% of the cases reported in the United States during this same time period. The state of Arkansas reported the highest total (420 cases). Annual incidence rates per one million population ranged from 36.3 in Arkansas to less than 5.0 in Kansas, Louisiana, and Texas. Epidemiologic data were available for 1,026 cases. The majority of cases were white (88%) and male (75%). May, June, and July were the months of onset of symptoms for 52% of the cases. For the cases with known exposure history, 63% reported an attached tick and 23% had exposure to rabbits. Other animals associated with human infection were squirrels, cats, and raccoons. The case-fatality ratio was 2%. Public health efforts to prevent human tularemia cases in the six southwest-central states should focus on reducing exposure to ticks.

Adolescent↗

A case study of the Tenwek hospital community health programme in Kenya.

Tenwek mission hospital, situated in the west-central highlands of Kenya, initiated a community health programme in 1984. This paper describes the major features of the programme and assesses the impact on a number of health and family planning practices after 3 years of implementation. Comparison of the results in the programme areas with the baseline survey and with control areas show significant changes in several indicators. It is concluded that Tenwek hospital demonstrated the impact a hospital can have on health of communities by effectively moving into community-based health care.

Community Health Services↗

Contact tracing to identify human immunodeficiency virus infection in a rural community.

This report describes a contact investigation conducted in rural South Carolina to identify, counsel, and educate persons infected with or exposed to the human immunodeficiency virus (HIV). Starting with one HIV antibody-positive man and his 19 sex contacts, we identified 83 sex contacts of HIV antibody-positive men. Of these, 64 were residents of the county and 63 (98%) agreed to be tested for evidence of HIV infection. Eight (13%) were HIV antibody positive. Thirty-six initially HIV antibody-negative men were reevaluated at a six-month follow-up visit, and three had seroconverted during this time. Of 25 men who reported practicing anal receptive intercourse, 13 (52%) were HIV antibody positive vs none of 43 men who reported strictly anal insertive intercourse. Comparing reported numbers of sexual contacts for the six-month periods before and after our initial investigation, the mean numbers of named sex contacts decreased by 82% for antibody-positive men and 54% for antibody-negative men. None of the men reported using condoms before entering the study; at the six-month follow-up visit, four (80%) of five of the antibody-positive men and 25 (69%) of 36 of the antibody-negative men reported using condoms at least some of the time.

Acquired Immunodeficiency Syndrome↗

Anterior sacral meningocele in pregnancy.

Anterior sacral meningocele is a rare abnormality. Only 14 cases of it have been reported in association with pregnancy. Of those 14 patients, three died as a result of rupture of the meningocele during labor and postpartum. A new case is presented; the clinical presentation, the diagnosis, and treatment are discussed. The obstetric management of the case is discussed and a plan for management is suggested.

Adult↗

Health care expenditures in a rural Indian community.

Financing health services is an increasing concern that looms as one of the major obstacles to achieving an equitable distribution of primary health care in developing communities. An important step in solving this problem is the assessment of current levels of health care expenditures in these communities in order to determine the extent to which local resources are being used for these purposes. Ways to maximize the effectiveness of these resources can then be sought. Village level studies carried out between 1968 and 1974 in Punjab, India, revealed that at least 80% of all health care expenditures in this rural area were for services of traditional practitioners or private 'modern' doctors. This paper explores various aspects of these expenditures including the source of services and the effect of individual characteristics such as caste on the amount spent on health care. Out-of-pocket expenditures are contrasted to expenditures in the government system. Assessment of the impact of 'free' village level primary care services in this setting revealed that the poor reduced their expenditures on health care more than the wealthy, but both groups took almost equal advantage of the 'free' services. The results raise the possibility of mobilizing some of the savings accruing to the community to help support the 'free' services as well as the potential of encouraging private traditional and modern practitioners to cooperate in achieving primary health care goals.

Developing Countries↗

Epidemiology of a tuberculosis outbreak in a South Carolina junior high school.

A 13-year-old, female, seventh-grade student (the index patient) was found to have smear-positive, cavitary, pulmonary tuberculosis. Epidemiologic and contact investigation, involving skin testing over 900 people, revealed a 40 per cent tuberculin reactor rate for persons in the junior high school she attended compared to a 2 per cent rate for control schools. Repeat skin testing of initial non-reactors identified an additional 3 per cent of infected school children. School teachers showed a seven-fold increase in the prevalence of positive skin-test reactions following the outbreak. Tuberculin-reactor rates for seventh graders were substantially higher than for eighth graders. The more classes shared with the index patient, the higher the probability of being a reactor. Among students who shared no classes with the index patient, the highest rates of tuberculin reactions were found for those who had entered a classroom immediately after the index patient had left it. Evidence of transmission on the school bus and in the church choir was also suggested. Six secondary cases (three pulmonary) resulted from the outbreak. Identical phage types from the index and secondary patients suggest who had left school during the term proved useful in determining when transmission began. The index case was found to be a missed contact of a previously identified case of tuberculosis. Since household contacts are at high risk for developing active disease, there is a need for meticulous and complete investigation and preventive therapy for all such persons, especially children.

Adolescent↗

The barefoot doctor: Shanghai County revisited.

Since a 1981 review of health status and health services in Shanghai County, there have been considerable social and economic changes in the People's Republic of China. A major question currently is the impact of the new economic "responsibility system," which was introduced in 1982, on the cooperative health structure and the "barefoot doctors" (BFDs). Investigators in other areas of China have reported the collapse of the cooperative systems and a shift in the role of the BFDs as a result of incentives for them to spend more time in agricultural production. In Shanghai County, however, BFDs continue essentially full time as before, salaried by the brigade, with fee-for-service charges prohibited. Recent evidence from Shanghai County shows that the health care system and those who direct it can remain flexible and respond positively to changes in the social, economic, and political structures.

China↗

Use of the human tumor stem cell assay to study chemotherapy sensitivity in cancer of the cervix.

Two questions concerning chemotherapy of cervical cancers are addressed in this study. 1) Can the human tumor stem cell assay identify active chemotherapeutic agents?; and 2) Can the human tumor stem cell assay predict which patient's tumors will demonstrate clinical responsiveness to chemotherapy? Sixty-seven of 76 cervical cancer specimens (88.2%) were grown in the human tumor stem cell assay, resulting in 159 separate drug assays. Based on the known activity of standard chemotherapeutic agents demonstrated in clinical trials, cisplatin, bleomycin, vincristine, and mitomycin C were chosen for testing. In vitro sensitivity patterns, seen at one-tenth of the peak plasma drug concentration, were similar to those seen in historic clinical trials. Retrospective correlations between in vitro drug sensitivity data and patient responses to chemotherapy are available from 13 patients, demonstrating clinically helpful predictive capabilities of the assay. Two conclusions were made: 1) The human tumor stem cell assay can determine single agent activity, which is often dose related; and 2) Useful correlations with clinical responses were observed.

Adenocarcinoma↗

Toxoplasmosis infection associated with eating undercooked venison.

Toxoplasmosis infection was documented in one Alabama and two South Carolina deer hunters in 1980. All three cases were acutely ill and required hospitalization. Physical findings included fever, leukopenia, and abnormal liver function tests. Two of the three patients showed infiltrates on chest x-ray. All three hunters had recently consumed raw or nearly raw venison and lacked other known risk factors for toxoplasmosis such as cat contact or eating other undercooked meats. In a serosurvey and questionnaire of 62 wildlife workers who regularly handled deer viscera, an association between seropositivity to Toxoplasma gondii and a history of eating raw or rare venison was found (p less than 0.05), but no significant association was found between seropositivity and any other risk factors. Eating inadequately cooked venison may represent an important vehicle of human toxoplasmosis infection.

Acute Disease↗

Tick testing as a method of controlling Rocky Mountain spotted fever.

In South Carolina, 1974-1980, only two matches were found between 536 Rocky Mountain spotted fever (RMSF) cases and 965 individuals who submitted ticks that tested rickettsial antigen positive. In neither case did the positive test prevent RMSF. Tick rickettsial positivity rates varied inversely with human RMSF attack rates in different geographic areas. A physician survey established it as unlikely that RMSF occurred in positive tick submitters (PTS), and that although not recommended, 34 per cent of asymptomatic PTS received prophylactic treatment. Only 18 per cent of positive ticks were engorged. Tick testing appears ineffective in preventing RMSF.

Child↗