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Biomedical subjects

J Roberts

Publications and source records attributed to J Roberts.

At least 379 records · Page 21Linked to original sources
PubMed1992

Prevalence and risk factors for Taenia solium taeniasis and cysticercosis in humans and pigs in a village in Morelos, Mexico.

In a Mexican village in which Taenia solium infection was known to be endemic, we selected a cluster sample of 368 households (21% of the total) for demographic, environmental, and diagnostic surveys, and medical histories for taeniasis and cysticercosis. Coproparasitologic studies of 1,531 participants revealed infection by Taenia sp. in four (0.3%) individuals; however, 5.8% of the respondents reported a history of having passed tapeworm proglottids in feces. Of 1,552 human serum specimens, 10.8% tested positive in the cysticercosis immunoblot assay. Seropositivity increased with age and reached a maximum in subjects ages 46-55 years. Risk factors associated with seropositivity included a history of passing tapeworm proglottids, frequent consumption of pork, and poor personal and household hygiene (P less than 0.05). A history of seizures was also significantly associated with seropositivity (P less than 0.05); approximately one-third of persons with such histories were seropositive. Of 571 pigs examined by tongue inspection, 23 (4.0%) had cysticerci; infection rates increased with the age of pigs, and were higher in pigs that habitually ran loose or were fed human feces (P less than 0.05). Goodness of fit analysis confirmed that seropositive persons (but not infected pigs) were significantly clustered within households, particularly, in households in which a member reported a history of having passed tapeworm proglottids. The results of this study have identified community behavioral and environmental practices that must be modified to prevent continued transmission of cysticercosis and taeniasis.

Adolescent↗
PubMed1992

Peripheral neuroepithelioma: a light microscopic, immunocytochemical, and ultrastructural study.

Forty-two cases of peripheral neuroepithelioma (PN) retrieved from the files of the National Cancer Institute (Bethesda, MD) and the Pathology Department of Padua University, Italy, were reviewed. No sex predilection was observed (25M/17F) and ages ranged from 7 to 54 yr (median 22 yr). Roughly a third of the tumors were thoracopulmonary ("Askin tumor"), a third were axial, and a third were in extremities. A lobular pattern with rosettes or pseudo-rosettes characterized PN. Seventeen cases showed a strong diastase-sensitive PAS positivity. Transitional areas with an Ewing's-like appearance and, in one case, transition to malignant nerve sheath tumor have been documented. The presence of neuron specific enolase (NSE), S-100 protein, HNK-1, neurofilaments, vimentin, keratin (AE1-AE3), beta 2-microglobulin, chromogranin A, and synaptophysin was investigated using the avidin-biotin technique. Immunocytochemically, NSE (95% of cases), beta 2-microglobulin (77.5%), synaptophysin (73.3%), and S-100 protein (67.5%) were the most consistently positive markers. Ultrastructurally, PN is characterized by a primitive appearance, although it was routinely possible to recognize neural features such as primitive neuritic extensions and dense core granules, either in the cytoplasm or in the cellular processes. In our experience, a light microscopic picture of a primitive round cell tumor with a lobular pattern, and particularly with rosettes when present, with NSE and beta 2-microglobulin positivity by immunocytochemistry, ideally with positive synaptophysin, along with supportive electron microscopy, is required for the diagnosis of PN. Conversely, no one feature alone is generally sufficient for diagnosis, but does allow distinction from extraosseous Ewing's, which (like osseous Ewing's) lacks features of neural differentiation.

Adolescent↗
PubMed1992

Treatment of gastric lymphoma.

A review of 52 patients with gastric lymphoma at the Texas A&M University College of Medicine Affiliated Scott and White Memorial Hospital (Temple, TX). was performed to determine the influence of different treatment modalities. Thirty-one patients had a potentially curative resection, while 21 underwent a palliative procedure or biopsy alone. Overall 5-year survival was 73.4 per cent after curative resection and 38.3 per cent for lesser operative procedures (P less than .005). Adjuvant radiation was given to 14 patients after curative resection with a 5-year survival rate of 71.5 per cent compared to 82.4 per cent in the 17 patients treated by curative resection alone (nonsignificant). Patients who underwent palliative surgery or biopsy who received postoperative radiation therapy had a 38.0 per cent 5-year survival rate compared to a 0.0 per cent 5-year survival rate in patients who received no therapy (P = .18). The authors conclude that curative resection is the treatment of choice for gastric lymphoma, but radiation therapy may offer some benefit when complete resection is not feasible.

Actuarial Analysis↗
PubMed1992

A defence against the menopause. Uses and applications of hormone replacement therapy.

The menopause can result in a number of distressing short- and long-term symptoms. Hormone replacement therapy has been found to combat many of these symptoms. Research indicates that HRT is much safer today than the general public and many of the medical profession are led to believe. HRT is prescribed to far fewer women in the UK than in Europe or America.

Estrogen Replacement Therapy↗
PubMed1991

Effect of age on presynaptic beta2 receptor mediated responses in the rat heart.

Presynaptic alpha2 adrenergic receptor inhibition of norepinephrine (NE) release is diminished in older animals [1]. To determine whether presynaptic beta2 adrenergic receptor facilitation of NE release is also affected by age, the effect of propranolol on neurally-induced NE release was examined in perfused heart preparations isolated from 6- and 24-month-old rats. The heart was isolated with the right cardiac sympathetic nerve and then was stimulated electrically in the absence and presence of propranolol (10(-8)-10(-6) M). NE content in the effluent was measured by an HPLC/EC methodology. The data indicate that there is a greater suppression of NE release by propranolol in preparation isolated from younger animals. For example, in nerve-heart preparations of 6-month-old animals stimulated at 12 Hz, propranolol (10(-6) M) reduced the amount of NE released by 34% whereas in preparations from 24-month-old animals at 12 Hz there was no significant change in the NE overflow. Like the alpha2 receptor mechanism, autoregulation of NE release by presynaptic beta2 receptors is diminished in older animals. Lack of presynaptic autoregulation may explain in part, the reduced capacity of adrenergic influences to control and regulate cardiac function in older animals.

Aging↗
PubMed1991

Gonadotropin-releasing hormone gene expression in MDA-MB-231 and ZR-75-1 breast carcinoma cell lines.

The presence of gonadotropin-releasing hormone (GnRH)-binding sites in human breast carcinomas and breast tumor cell lines as well as the demonstration of the inhibitory effects of GnRH analogues on the growth of these cells raised the possibility that GnRH is produced locally by breast tumor cells themselves. Immunoreactive GnRH was shown to be present in acetic acid extracts of cultured MDA-MB-231 and ZR-75-1 breast carcinoma cells. These extracts were separated by high-performance liquid chromatography and were analyzed by means of region-specific antisera with differing GnRH sequence specificities. A peak of GnRH which coeluted with synthetic mammalian GnRH in 2 different high-performance liquid chromatography systems was similarly detected by antisera directed at the NH2 terminus, at the middle portion and at the N and COOH termini together. The GnRH gene is expressed in these breast tumor lines, as determined by S1 nuclease protection assay, oligonucleotide primer extension studies, and polymerase chain reaction amplification of complementary DNA using oligonucleotides. The primer extension studies indicate that several forms of mRNA are present. The predominant form corresponds to the excision of intron I and the use of a start site about 60 bases upstream of intron I as in the human hypothalamus. Less usage is made of other start sites further upstream. Much larger species of mRNA were also present and correspond to the retention of intron I as in human placenta. The demonstration of GnRH gene expression and the presence of immunoreactive GnRH in mammary carcinoma cells known to have GnRH-binding sites and to be affected by GnRH analogues suggests that GnRH may serve an autocrine regulatory role.

Base Sequence↗
PubMed1991

Psychosocial adjustment in women with breast cancer.

There is a plethora of studies investigating psychosocial adjustment in women with breast cancer, its correlates, clinical course, and prognosis. These studies have been conducted with varying degrees of methodologic rigor. An assessment has been made of the quality of this existing evidence to identify from the best evidence the factors which predict the adjustment status of women with breast cancer. Studies have been reviewed, using methodologic standards for the critical appraisal of studies on prognosis, developed by Sackett and colleagues in the Department of Clinical Epidemiology and Biostatistics at McMaster University (Hamilton, Ontario, Canada). Few of the studies investigating psychosocial adjustment of women with breast cancer meet all of the criteria for reviewing studies of clinical course and prognosis. This review focuses the direction and methodologic rigor required in future investigations. In particular, studies are needed that employ prospective designs and that deliberately measure or control for the extraneous prognostic variables that may affect adjustment. Future investigations need to incorporate adequate precision in measurement so that measures of the psychosocial variables are objective, reliable, and valid.

Adaptation, Psychological↗
PubMed1991

Hepatitis C in patients undergoing liver transplantation.

OBJECTIVE: To determine the prevalence of antibodies to hepatitis C virus (anti-HCV) among patients undergoing liver transplantation and the relation between anti-HCV and post-transplant hepatitis. DESIGN: Retrospective cohort. PATIENTS: Serum samples from 128 patients who underwent liver transplantation. Sixty-six patients who had 6 months of follow-up and for whom both pretransplant and post-transplant serum samples were available were included in a study to asses the relation between anti-HCV and post-transplant hepatitis. MEASUREMENTS: Sera were tested for anti-HCV using an enzyme-linked immunosorbent assay (ELISA) and, if positive, two confirmatory tests were done. Patients had a biopsy every week until two specimens showed no abnormal findings. MAIN RESULTS: Only patients with chronic non-A, non-B hepatitis (15 of 30; 50%), alcoholic cirrhosis (7 of 19; 37%), and chronic hepatitis B infection (3 of 11; 27%) were anti-HCV positive. No patient with another form of chronic liver disease or with acute liver failure due to non-A, non-B hepatitis was anti-HCV positive. After transplantation, loss of anti-HCV was frequent and acquisition rare. Hepatitis developed in the graft in 17% of patients, but the incidence was similar among anti-HCV negative and anti-HCV-positive patients. CONCLUSIONS: Hepatitis C virus is a common cause of chronic liver disease in patients requiring liver transplantation, but anti-HCV is rarely found in patients with acute liver failure. Previous HCV infection, based on detection of anti-HCV, is not an independent risk factor for post-transplant hepatitis.

Cohort Studies↗