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Biomedical subjects

R Howell

Publications and source records attributed to R Howell.

At least 37 records · Page 2Linked to original sources
PubMed1995

Endocrine effects of GnRH analogue with low-dose hormone replacement therapy in women with endometriosis.

OBJECTIVE: GnRH analogues are being used increasingly for a number of oestrogen dependent conditions in women. The resultant profound hypo-oestrogenism is a disadvantage, however, but the preservation of pituitary sensitivity to negative feedback by oestradiol is not well defined. We have determined the effect on gonadotrophins and inhibin of GnRH analogue plus low-dose continuous combined hormone replacement therapy in comparison with GnRH analogue therapy alone. DESIGN: Randomized controlled trial. PATIENTS: Fifty premenopausal women with endometriosis randomized to treatment with goserelin alone (Group 1) or goserelin plus 17 beta-oestradiol and medroxyprogesterone acetate (Group 2). MEASUREMENTS: FSH, LH, oestradiol, oestrone, inhibin before and during treatment. RESULTS: Oestradiol and oestrone were suppressed in both groups, but Group 2 had significantly higher oestradiol during the hormone replacement therapy period. LH was suppressed in both groups. In Group 1, FSH levels recovered during treatment but, in contrast, in Group 2, FSH levels remained suppressed throughout treatment. Inhibin was significantly lower in Group 2, but not in Group 1, during treatment compared to pretreatment. CONCLUSIONS: Pituitary secretion of FSH appears to remain responsive to feedback control by oestradiol during GnRH analogue therapy and is incompletely suppressed, unlike LH which remains completely suppressed. The possible mechanisms for this are discussed.

Adult↗
PubMed1994

Diploid and hyperdiploid rat Schwann cell strains displaying negative autoregulation of growth in vitro and myelin sheath-formation in vivo.

Neonatal rat Schwann cells were cultured for several months with intermittent exposure to the mitogen, cholera toxin, and infrequent passaging to avoid premature transformation. A cell line SCL4.1/F7 was derived following the cloning of one of these long-term cultures by limiting dilution in liquid medium to select for cells capable of continuous proliferation in the absence of mitogen. F7 cells have been passaged 40 times (80-120 generations) over 14 months. Two substrains were identified at passage 20, one of which ,s diploid and the other which has trisomy 7 (t7). The cell line displays a characteristic flattened or crescent-shaped morphology, substratum adhesion which is calcium-dependent in the millimolar range, and pronounced contact-inhibition of growth. Confluent or subconfluent cultures readily cease proliferation and change to a differentiated (stellate/bipolar) morphology through the mediation of an autocrine growth-inhibitory factor. F7 cells grafted into the site of a crush injury in adult rat sciatic nerves remained viable and myelinated host axons. F7 is the first clonally derived diploid immortal Schwann cell line to have been published and should provide a suitable tool for the study of the biochemical and cellular basis of sheath cell-neuron interactions, myelin stabilization in peripheral nerve and Schwann cell growth autoregulation.

Animals↗
PubMed1991

Rapid culture confirmation of herpes simplex virus by a monoclonal antibody-based enzyme immunoassay.

Rapid confirmation of herpes simplex virus (HSV) is essential in many clinical settings. Viral isolation in cell culture is the standard method for diagnosing HSV infection, with confirmation by specific immunological staining. The performance of the Rapid Absorbent Matrix Pad (RAMP) HSV culture confirmation test was evaluated with specimens obtained from 71 patients with suspected HSV infection and inoculated into African green monkey kidney cell lines. Forty-one culture-positive specimens were confirmed to be HSV by both the RAMP HSV test and the Bartels HSV immunoperoxidase test. Thirty immunoperoxidase-negative specimens were also negative in the RAMP HSV test. The sensitivity and specificity of the RAMP HSV test were 100%. Twelve specimens positive for cytomegalovirus, adenovirus, or enterovirus tested negative by the RAMP HSV test. Thus, the RAMP HSV test was faster than, easier to perform than, as sensitive as, and as specific as other well-documented confirmation methods.

Antibodies, Monoclonal↗
PubMed1991

HIV roundtable. Strategies to enhance professional awareness and involvement. Part II.

Despite extensive public attention to the social and medical problems associated with HIV infection and AIDS, many clinicians remain largely uninvolved in public health and patient counseling programs aimed at preventing infection and getting patients into treatment. Suggestions to enhance professional involvement include improved schooling and continuing medical education; increased liaison and exchange of information among the various groups working with AIDS patients and at-risk populations; and programs to help clinicians confront their own feelings and concerns relating to AIDS.

Community-Institutional Relations↗
PubMed1991

HIV roundtable. Professional perspectives.

As the HIV epidemic escalates, concern is mounting over the implications of infection among health care workers. Should all medical professionals be tested? Should supervisors and/or patients be notified if the results are positive? Should the infected PA continue to practice? What about performing surgery? Should he or she be considered impaired? And what about the long-term stress of working with HIV patients? Experts discuss the AAPA's latest recommendations, and share suggestions on prevention and patient care with the audience.

Cross Infection↗
PubMed1991

The histologic reliability of laser cone biopsy of the cervix.

Laser conization of the cervix has been advocated as the technique of choice for the treatment of cervical intraepithelial neoplasia (CIN) in preference to ablative techniques, because it provides a specimen for histologic diagnosis while retaining the advantages of an outpatient procedure with minimal short- and long-term morbidity. To determine whether specimens so obtained are adequate for reliable histologic diagnosis, we reviewed 77 laser conizations performed for lesions confirmed to contain CIN in a colposcopically directed biopsy and satisfying the criteria for local ablation and scored the cones for the presence of epithelial denudation and laser coagulation artifact that interfered with the diagnosis of CIN or the assessment of the margins of excision. Thirty specimens (39%) were negative for CIN. Twenty-eight (36%) showed extensive epithelial denudation, ten (13%) contained coagulation artifact that made recognition of CIN extremely difficult or impossible, and in 11 (14%), assessment of margins was extremely difficult or impossible because of laser coagulation artifact. We conclude that these difficulties with the histologic interpretation of laser cone specimens make it an unsuitable excisional technique when reliable histologic diagnosis of cervical lesions is required.

Adult↗
PubMed1990

HIV roundtable. Strategies to enhance professional awareness and involvement, Part I.

Despite extensive public attention to the social and medical problems associated with HIV infection and AIDS, many clinicians remain largely uninvolved in public health and patient counseling programs aimed at preventing infection and getting patients into treatment. Suggestions to enhance professional involvement include improved schooling and continuing medical education; increased liaison and exchange of information among the various groups working with AIDS patients and at-risk populations; and programs to help clinicians confront their own feelings and concerns relating to AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Circulating levels of placental protein 12 in complications of first trimester pregnancy.

Serum placental protein 12 (PP12) levels were determined in 34 women with threatened miscarriage in whom a diagnosis of anembryonic pregnancy (n = 19), missed abortion (n = 4), complete or incomplete abortion (n = 5), hydatidiform mole (n = 1) and subsequent abortion of a live fetus (n = 5), was made ultrasonically and confirmed by histological examination. Twenty-four of the 34 patients had one or more levels between the 10th and 90th centiles of the reference range. In 7 of the 19 patients (37%) with anembryonic pregnancy and in 3 of the 4 patients (75%) with a missed abortion, PP12 levels were markedly elevated. However, in cases where serial measurements were available (n = 6), PP12 levels were seen to fall in all cases. It is concluded that pregnancies that have failed or will subsequently fail in the first or second trimester are not associated with depressed maternal PP12 levels, suggesting that the decidual synthesis of this protein is independent of the presence or viability of the fetus.

Abortion, Spontaneous↗
PubMed1989

Philippino and Vietnamese women--a study of intrapartum differences.

The pregnancies of 140 Philippino women (168 deliveries) and 198 Vietnamese women (250 deliveries) were compared to those of Australian-born women delivered at the Mater Mothers' Hospital, Brisbane over the 5-year period 1980-1984 with the aim of detecting differences in their labour and mode of delivery. The Philippino women were predominantly married to Caucasian men whereas the Vietnamese women were married to Vietnamese men. The study assesses the clinical impression that this difference between the 2 groups affects intrapartum outcome. Birth-weights of the babies of Philippino women followed the same pattern as those of Australian women while Vietnamese women delivered smaller babies. Philippino primiparas had increases in all parameters of labour studied, notably an increased Caesarean section rate, especially those performed in the second stage. Comparable increases were not found in either Philippino multiparas or Vietnamese women. Based on these results 'relative' cephalopelvic disproportion is postulated among the Philippino women.

Adult↗
PubMed1989

Levels of the small insulin-like growth factor-binding protein are strongly related to those of insulin in prepubertal and pubertal children but only weakly so after puberty.

We have looked at the relationship between fasting levels of insulin and a small insulin-like growth factor (IGF)-binding protein (IBP-1) in a cross-sectional study of 116 normal subjects aged 5-48 years. The relationship between IBP-1 and insulin was also examined within individual normal children in overnight profiles of IBP-1 and insulin obtained from two children at each stage of puberty (Tanner stages 1-5). In the cross-sectional study high levels of IBP-1 were found in early childhood and these fell throughout puberty as fasting levels of insulin rose. Multiple regression analysis revealed that both these changes were predominantly due to pubertal development rather than to age. After the age of 16 IBP-1 levels remained low despite fasting insulin levels returning to prepubertal levels. A strong negative correlation was obtained between IBP-1 and insulin in children of 5-16 years (r = -0.63; n = 60; P less than 0.001), no such relationship being found after the age of 16. In the second study, IBP-1 underwent a marked circadian variation in all cases and an inverse correlation with insulin, measured at the same time, was obtained at pubertal stages 1 to 4, but not at stage 5 (pooled data stages 1-4, r = -0.69; n = 53; P less than 0.001). We have demonstrated that a potential inhibitor of IGF-activity is inversely related to insulin throughout the period of active GH-related growth and that this relationship weakens after puberty.

Adolescent↗
PubMed1988

Circadian variation of GH-independent IGF-binding protein in diabetes mellitus and its relationship to insulin. A new role for insulin?

Evidence is accumulating that a non-GH dependent insulin-like growth factor-binding protein (IGF-BP) is not only a carrier protein but also has an active role in the growth process. We have measured levels of this IGF-BP, using a specific RIA, over 12 or 24-h periods in 11 adolescents with diabetes mellitus and five normal adults. In each of the normal the IGF-BP was undetectable for most of the day but with a broad nocturnal peak observed, with levels up to 50 micrograms/l. The levels of IGF-BP were unrelated to the secretory pattern for GH but correlated inversely with the concentration of circulating insulin. In the diabetics a very similar pattern was observed, but with detectable levels throughout the day and much higher peak levels seen at night. Peak levels were up to 120 micrograms/l if a long-acting insulin preparation was administered in the evening but were 400-500 micrograms/l if the long-acting preparation was administered in the morning. The IGF-BP was strongly correlated with plasma glucose in this latter group. In a further group of diabetics overnight profiles were obtained on two separate nights, a normal night and a night with euglycaemia maintained with a glucose clamp technique. Euglycaemia failed to affect peak levels of the binding protein, although the shape of the nocturnal peak was altered consistent with the altered pattern of circulating free insulin. In this group a strong inverse correlation was obtained between the IGF-BP and free insulin levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Immunologic thrombocytopenia in pregnancy; use of antenatal immunoglobulin therapy: case report and review.

Steroid therapy remains the treatment of choice for immunologic thrombocytopenia in pregnancy. However, for cases refractory to steroid therapy, alternate forms of treatment must be used. This case report and review discusses a successful technique for acute, short-term correction of thrombocytopenia. In limited experience the administration of high-dose immunoglobulin appears to be effective for antepartum use in patients with immunologic thrombocytopenia. The concomitant or subsequent performance of splenectomy appears to be a valuable adjunct in long-term treatment of this condition.

Adult↗
PubMed1984

Ampicillin combined with sulbactam or metronidazole for single-dose chemoprophylaxis in major gynaecological surgery.

A double-blind, placebo-controlled and randomized trial involving a total of 295 patients was carried out to define the role of chemoprophylaxis in major gynaecological surgery in our hospital. Perioperative administration of a single dose of ampicillin (500 mg) plus sulbactam (500 mg) (regimen A), or ampicillin (500 mg) plus metronidazole (1 g suppository) (regimen B), gave similar results. After abdominal hysterectomy, the rates of post-operative wound infection and febrile morbidity were significantly reduced from 24% (12/49) and 20% (10/49) in the placebo group to 3-4% (A = 2/51, B = 3/58) and 2% (A = 1/51, B = 1/58) respectively. After vaginal hysterectomy, pelvic/vaginal infection or febrile morbidity was found in 30% (3/10) of patients in the placebo group but none in either treatment group (A = 10, B = 8). After other types of operation, the rates of infectious complications were reduced, but not statistically significantly, from 11% (4/38) to 4% (A + B 2/71). However, the rates of post-operative urinary tract infection remained similar in the placebo and treatment groups (12-16%).

Adult↗
PubMed1983

The risks of antenatal subcutaneous heparin prophylaxis: a controlled trial.

The risks of long-term antenatal subcutaneous heparin therapy were assessed in a small controlled trial of prophylaxis of thromboembolism. Forty patients with a documented history of previous thromboembolism were randomly allocated either to receive heparin (10000 i.u. subcutaneously twice daily) throughout pregnancy and labour or to receive no treatment (control group). All patients were treated with heparin (8000 i.u. twice daily) for 6 weeks after delivery from the first postnatal day. There appeared to be no increased risk of antenatal or postnatal bleeding associated with subcutaneous heparin, but one patient in the control group developed a deep vein thrombosis and one in the treatment group developed severe debilitating osteopenia. The withholding of epidural analgesia may have contributed to both maternal and fetal morbidity in the treatment group. There was one abortion in each group but no other fetal or neonatal losses although more babies from the treated group entered the special care baby unit. Although the numbers are too small for statistical analysis, the findings indicate that the use of long-term low-dose subcutaneous heparin is not without complications and there is need for a larger, multicentre trial to allow precise quantification of fetal and maternal risks against the risk of recurrent thromboembolism.

Abortion, Spontaneous↗
PubMed1981

The black mink (Mustela vison). A natural model of immunologic male infertility.

Breeding for fine black fur has generated a colony of mink wherein 20-30% of the males are infertile. Two clinical groups are distinguishable: one being infertile from the start (primary infertility), and the other infertile after one or more years of fertility (secondary fertility). Although the etiology of primary infertility is unknown, the available data indicate that secondary infertility is associated with an autoimmune disease of the testis. Thus, male mink with secondary infertility have (a) higher prevalence and levels of anti-sperm antibody when compared with animals with primary infertility, and the antibody prevalence varies with fur color; (b) severe monocytic orchitis (47%) and/or aspermatogenesis (75%) with negative cultures for bacterial, fungal, mumps, or Coxsackie B viral organisms; (c) massive and extensive granular deposits of mink IgG and/or C3 (71%), typical of immune complexes, along the basal lamina of seminiferous tubules; (d) testes that when eluted with buffer or low pH yielded IgG that was 10-fold enriched in anti-sperm antibody activity as compared with serum IgG; and (e) no immunopathologic evidence of Aleutian mink disease. Although the sperm antigen-antibody complexes in the testis may be important as a pathogenetic mechanism of the testicular disease, there is no correlation between fluorescent anti-sperm antibody detection in the serum and the infertile state. The infertile black mink is a new model of infertility associated with naturally occurring autoimmune disease of the testis.

Animals↗