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Biomedical subjects

A Marks

Publications and source records attributed to A Marks.

At least 73 records · Page 4Linked to original sources
PubMed1990

Adolescent medicine in pediatric practice.

Adolescents report important unmet health care needs. This study directly assesses pediatricians' current practices pertinent to the primary care of adolescents. An anonymous questionnaire survey of general pediatricians was conducted in two suburban counties in New York State. Of the 101 respondents, 51% were older than age 50 and 88% were in private practice. The "average" pediatrician saw 28 patients in a 7-hour office day. Approximately 1 in 10 regularly saw patients with a sexuality-related concern, substance abuse problem, or anorexia nervosa. Fewer than half provided anticipatory guidance regarding sexuality, and only 14% questioned teens about depression. Respondents perceived factors related to fees, lack of time, lack of knowledge, and their image as obstacles to an expanded care of adolescents. Those with some training in adolescent medicine during residency were significantly more likely to provide care and anticipatory guidance related to sexuality and substance abuse. Thirty percent reported an interest in increasing their involvement with adolescents. We conclude that most of these pediatricians played a small role in meeting the health needs of adolescents.

Adolescent↗
PubMed1990

Ascitic fluid from human ovarian cancer patients contains growth factors necessary for intraperitoneal growth of human ovarian adenocarcinoma cells.

Human ovarian cancer, the leading cause of death from gynecologic malignancy, tends to remain localized to the peritoneal cavity until late in the disease. In established disease, ascitic fluid accumulates in the peritoneal cavity. We have previously demonstrated that this ascitic fluid is a potent source of in vitro mitogenic activity including at least one unique growth factor. We now report that the human ovarian adenocarcinoma line, HEY, can be induced to grow intraperitoneally in immunodeficient nude mice in the presence (23/28 mice), but not absence (0/21 mice) of ascitic fluid from ovarian cancer patients. Ascitic fluid from patients with benign disease did not have similar effects on intraperitoneal growth of HEY cells (1/15 mice). Once tumors were established by injections of exogenous ascitic fluid, they could progress in the absence of additional injections of ascitic fluid. The mice eventually developed ascitic fluid which contained potent growth factor activity, suggesting that the tumors eventually produced autologous growth factors. This nude mouse model provides a system to study the action of ovarian cancer growth factors on tumor growth in vivo and to evaluate preclinically, therapeutic approaches designed to counteract the activity of these growth factors.

Animals↗
PubMed1989

Expression of the gene encoding the beta-subunit of S-100 protein in the developing rat brain analyzed by in situ hybridization.

To investigate patterns of expression of the gene encoding the beta-subunit of S-100 protein during development of the rat brain we have used Northern blotting and in situ hybridization histochemistry. During late prenatal development beta-S-100 mRNA was observed first in the germinal zone lining the 4th ventricle. In the postnatal cerebellum this mRNA accumulated primarily in Bergmann glia and astrocytes of the deep white matter. In the hindbrain, expression of S-100 mRNA increased steadily in specific regions during the first postnatal week while levels remained low in more anterior brain regions. By the end of the second postnatal week, a dense punctate signal was distributed throughout the midbrain and hindbrain. Expression in forebrain, first observed at E18, was confined to cells lining the ventricle until the second postnatal week when accumulation of mRNA was observed in specific regions of the hippocampus, neocortex and olfactory bulb. The adult brain pattern of beta-S-100 mRNA distribution is attained during the third postnatal week. These results demonstrate a caudal-rostral gradient in expression of the beta-S-100 gene during rat brain development, as well as pronounced regional differences which may reflect the differentiation of subpopulations of astrocytes.

Aging↗
PubMed1989

Prevalence of Toxoplasma gondii infection in cats in Georgia using enzyme-linked immunosorbent assays for IgM, IgG, and antigens.

Serologic prevalence of Toxoplasma gondii infection was determined using enzyme-linked immunosorbent assays detecting immunoglobulin M (IgM), immunoglobulin G (IgG), and circulating T. gondii antigens (Ag) in 81 healthy cats and 107 cats with clinical signs referable to toxoplasmosis. A higher prevalence of infection was detected using the three assays together in healthy cats, clinically ill cats, and combined healthy and clinically ill cats than when IgG class antibody detection alone was used. IgM titers greater than or equal to 1:256 and IgG titers greater than or equal to 1:512 were present more frequently in cats with clinical signs of disease. Prevalence of present or prior infection as defined by these three assays combined increased with advancing age in both groups of cats.

Animals↗
PubMed1989

Labelling of monoclonal antibodies 10B, 8C, and M2A with indium-111.

Monoclonal antibodies 10B, 8C and M2A were conjugated with cyclic DTPA anhydride to a substitution level of 1-2 mol DTPA/mol antibody. The DTPA-conjugated antibodies were purified by size-exclusion mini-column chromatography and labelled with [111In]In acetate to a specific activity of 37-74 kBq/micrograms (1-2 microCi/micrograms). The radiochemical purity of the antibody preparation was 76-81%. The immunoreactive fraction of the radiolabelled antibodies ranged from 0.17 to 0.31, significantly lower than that of their radioiodinated analogs.

Antibodies, Monoclonal↗
PubMed1989

Why don't British radiotherapists give single fractions of radiotherapy for bone metastases?

A sample of 42 out of 80 delegates at RADIOLOGY '87 were asked about their treatment of a hypothetical patient with bone metastases from carcinoma of the breast. Details of their experience, the proportion of palliative work performed and the location of their centre were obtained. Only 36% gave a single fraction of radiotherapy, whereas 64% used multiple fractions. This confirms that despite many publications suggesting single fractions of radiotherapy are more cost effective and as good as fractionated treatment schedules in terms of pain relief, the need for retreatment and side-effects, the majority of British radiotherapists still use multiple fractions. Of the group using multiple fractions, 67% gave training as a reason for not using a single fraction, departmental policy being the second most quoted reason. Fear of recurrence, problems of retreatment and acute nausea were more of an influence than initial response or long-term effects. The presence of neurological signs or symptoms made the majority of delegates choose multiple fractions. An increased use of single fractions was noted in the Midlands and North of England compared with the South. Practice is unlikely to change unless there is an increased emphasis on palliative techniques in training.

Adult↗
PubMed1989

A novel maturation marker for human Sertoli cells.

The maturation of Sertoli cells at puberty is critical for the initiation and maintenance of spermatogenesis. Little is known about the factors which control Sertoli cell maturation. We have examined Sertoli cells in testicular specimens from 44 subjects, ranging in age from 6 months to 67 years, for reactivity with a mouse monoclonal antibody (M2A) using the immunoperoxidase reaction. We found positive reactivity with prepubertal but not postpubertal Sertoli cells, suggesting that the antigen defined by M2A was a marker of immature Sertoli cells. This marker may be useful for studying the factors which influence Sertoli cell maturation during development of the testis.

Adolescent↗
PubMed1989

Potassium restoration in hypertensive patients made hypokalemic by hydrochlorothiazide.

Among 447 hypertensive patients, most with a history of diuretic-induced hypokalemia, 252 developed diuretic-induced hypokalemia while receiving hydrochlorothiazide, 50 mg/d. In a randomized study we evaluated the efficacy of three drug regimens in restoring potassium levels while maintaining blood pressure control: hydrochlorothiazide (50 mg/d) plus potassium supplement (20 mmol/d); hydrochlorothiazide (50 mg/d) plus potassium supplement (40 mmol/d); or hydrochlorothiazide (50 mg/d) with triamterene (75 mg/d) in one combination tablet. In all groups, mean serum levels of potassium rose within 1 week and showed no further change thereafter. However, the hydrochlorothiazide/triamterene and hydrochlorothiazide plus 40 mmol of potassium regimens were significantly more effective in restoring serum potassium levels than was the hydrochlorothiazide plus 20 mmol of potassium regimen. A significant increase in magnesium levels was observed only in the group treated with the hydrochlorothiazide/triamterene combination. Each regimen provided continued control of mild to moderate hypertension.

Adult↗
PubMed1989

Effect of clindamycin on factor-VII activity in healthy cats.

Four healthy cats were given clindamycin orally in daily doses of 25 or 50 mg/kg of body weight for 6 weeks. Significant change in Factor-VII activity was not found, compared with pretreatment values. In 2 cats tested, toxin produced by Clostridium difficile was not detected in fecal samples obtained before treatment and at 6 weeks after treatment, suggesting that intestinal overgrowth by C difficile did not develop. Results of the study seemed to indicate that orally administered clindamycin does not measurably reduce synthesis of vitamin K-dependent clotting factors in healthy cats.

Animals↗
PubMed1988

Gene encoding the beta subunit of S100 protein is on chromosome 21: implications for Down syndrome.

S100 protein is a calcium-binding protein found predominantly in the vertebrate nervous system. Genomic and complementary DNA probes were used in conjunction with a panel of rodent-human somatic cell hybrids to assign the gene for the beta subunit of S100 protein to the distal half of the long arm of human chromosome 21. This gene was identified as a candidate sequence which, when expressed in the trisomic state, may underlie the neurologic disturbances in Down syndrome.

Chromosome Mapping↗
PubMed1988

A monoclonal antibody as a marker for carcinoma in situ germ cells of the human adult testis.

Carcinoma in situ of the testis (CIS) is a precursor of invasive testicular germ cell tumours. The diagnosis of CIS is however often missed when conventional histological techniques are used. No specific immunological marker for CIS germ cells of the testis has been demonstrated previously. A novel monoclonal antibody, M2A, reacting with malignant germ cells of seminomas has recently been developed. Using the immunoperoxidase reaction on tissue sections, we tested the reactivity of M2A with CIS germ cells of the human adult testis. Positive reaction was found in 19 of 20 testicular specimens showing CIS, whereas no staining was found in 39 testicular biopsies without CIS. Thus, M2A may serve as a diagnostic marker in detection of CIS germ cells.

Adult↗
PubMed1988

Use of anti-seminoma monoclonal antibody to confirm the diagnosis of mediastinal seminoma. A case report.

Chest x-ray in a 20-year-old man showed a large anterior mediastinal mass and a needle aspirate was diagnosed by light microscopy (LM) as non-Hodgkin's lymphoma. Treatment with CHOP (cyclophosphamide, adriamycin, vincristine and prednisone) was ineffective and a tissue biopsy was performed. LM showed large, non-cohesive cells with abundant cytoplasm and rounded nuclei. Differential diagnoses included malignant lymphoma, seminoma, thymoma, anaplastic carcinoma, malignant melanoma and paraganglioma. Electron microscopy was not conclusive and immunoperoxidase staining was carried out. The malignant cells were negative for common leukocyte antigen, Leu M1, alpha-fetoprotein, chorionic gonadotrophin, cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, S-100 protein and neuron-specific enolase but positive for placental alkaline phosphatase. In addition, there was strong positivity with a monoclonal antibody (mAb) which was recently shown to react with testicular seminomas. This case illustrates the value of this mAb in confirming the diagnosis of mediastinal seminoma.

Adult↗
PubMed1988

Reactivity of tumor cells in malignant effusions with a panel of monoclonal and polyclonal antibodies.

A panel of 13 mouse monoclonal antibodies (mAb) and 1 rabbit polyclonal antibody was tested for reactivity with tumor cells in 26 effusions obtained from patients with carcinoma of ovary, breast, or mesothelioma, using an immunoperoxidase staining reaction. Specific staining of tumor cells but not reactive mesothelial cells was demonstrated with some of the mAb in the panel. In 4 of 26 effusions no evidence of malignancy was obtained after routine cytological staining, but this was reversed on the basis of immunoperoxidase staining of tumor cells with the mAb in the panel. Serial effusions were evaluated in 4 patients during the course of chemotherapy, allowing an assessment of effect of therapy on the antigenic characteristics of the tumor cells. In another 4 patients, the results of immunoperoxidase staining of effusions were compared with those obtained by applying the same antibody panel to solid tumor nodules. There was a tendency to develop changes in the pattern of reactivity during therapy, and the pattern of reactivity was more restricted in tumor nodules than in effusions. One of the mAb in our panel (2G3) was consistently shown to produce strong staining of a high proportion of tumor cells in effusions and tumor nodules from patients with ovarian or breast cancer and may be of value in immunocytochemical diagnosis and therapy of epithelial malignancies.

Animals↗
PubMed1988

Meeting the health care needs of suburban youth: review of a clinical service.

The demographic and medical data from the first 1,000 patients registered at a suburban adolescent health service were reviewed and the findings compared with the results of an initial survey performed in the same community and other health services located in urban communities. Most of the patients were white (92%), girls (82%), and 16 to 18 years of age (63%) and had parents who graduated from high school (59%) or college (28%). They reported higher rates of participation in health-risk behaviors, including smoking (50%), drinking (60%), drug use (67%), and sexual intercourse (83%), than their peers. Seventy-two percent of the patients sought medical attention for sexuality-related or gynecologic concerns, including contraception (39%), pregnancy determination (20%), and evaluation of possible sexually transmitted disease (9%), and 28% sought attention for general medical or emotional needs, including checkups or immunizations (11%), nutritional or weight problems (4%), and emotional issues or substance abuse (4%). Management of sexuality-related issues differed from that reported in urban settings, whereas laboratory screening tests indicated that problems were similar to those in other settings. Many problems described in an initial survey of youth in the community were not seen at the adolescent health service. We conclude that a suburban-based health service may meet certain health care needs of the higher risk youth of the community but that ultimate care for adolescents remains with the private physicians in this setting.

Adolescent↗