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Biomedical subjects

D Powers

Publications and source records attributed to D Powers.

At least 19 recordsLinked to original sources

A collaborative hit-to-lead investigation leveraging medicinal chemistry expertise with high throughput library design, synthesis and purification capabilities.

High throughput screening (HTS) campaigns, where laboratory automation is used to expose biological targets to large numbers of materials from corporate compound collections, have become commonplace within the lead generation phase of pharmaceutical discovery. Advances in genomics and related fields have afforded a wealth of targets such that screening facilities at larger organizations routinely execute over 100 hit-finding campaigns per year. Often, 10(5) or 10(6) molecules will be tested within a campaign/cycle to locate a large number of actives requiring follow-up investigation. Due to resource constraints at every organization, traditional chemistry methods for validating hits and developing structure activity relationships (SAR) become untenable when challenged with hundreds of hits in multiple chemical families per target. To compound the issue, comparison and prioritization of hits versus multiple screens, or physical chemical property criteria, is made more complex by the informatics issues associated with handling large data sets. This article describes a collaborative research project designed to simultaneously leverage the medicinal chemistry and drug development expertise of the Novartis Institutes for Biomedical Research Inc. (NIBRI) and ArQule Inc.'s high throughput library design, synthesis and purification capabilities. The work processes developed by the team to efficiently design, prepare, purify, assess and prioritize multiple chemical classes that were identified during high throughput screening, cheminformatics and molecular modeling activities will be detailed.

Chemistry, Pharmaceutical↗

Recent trends in assisted reproductive techniques and associated outcomes.

OBJECTIVE: We examined recent trends in success rates for assisted reproduction and determined the influence of changes in patient selection and treatment characteristics on these trends. METHODS: We collected baseline information and abstracted treatment-related details and outcomes on 1244 couples accepted for in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT) at three clinics in greater Boston from 1994-1998. RESULTS: Delivery rates per initiated cycle improved significantly from 14.9% for IVF and 20.6% for GIFT in 1994-1995 to 22.5% for IVF and 28.0% for GIFT in 1997-1998 (P < or = .001). After adjusting for female age, the two treatment-related variables that appeared most likely to explain this trend were decreased use of GnRH agonists in short course (flare) regimens and increased use of highly purified forms of urinary gonadotropins. CONCLUSION: There were significant improvements in the success rates for IVF and GIFT from 1994-1998 that correlated with changes in ovulation induction regimens.

Adult↗

Recruiting women into a smoking cessation program: who might quit?

This article describes women who called a research line to quit smoking and identifies correlates of confidence in quitting among the callers. Approximately 4,000 women called the study line to participate after a single press release, indicating intensive interest in quitting. Overall, the randomized sample of women was aged 26 to 65 years, reported smoking just over one pack per day, was mostly White, predominantly employed, and had quit an average of two times the past year before joining the study. Standard background variables, such as age, income, body weight and smoking history variables did not predict baseline self-efficacy or confidence in quitting. However, level of stress, cognitive restraint, and weight gain concerns did predict self-efficacy. These data indicate strong interest in quitting among women and highlight the role of affect and weight concerns in quitting confidence.

Adult↗

Patient with insufficient glandular tissue experiences milk supply increase attributed to progesterone treatment for luteal phase defect.

A case report is presented on the experience of a mother diagnosed with insufficient glandular tissue at 3 months postpartum with her first child who then went on to breastfeed her second child (fifth pregnancy) without supplementation of any kind. The mother had difficulty becoming pregnant and maintaining a pregnancy. She was diagnosed with a luteal phase defect and was thus treated with natural progesterone during her fifth pregnancy. The authors speculate that this treatment may have stimulated the development of her mammary alveolar cells, allowing lactation to progress normally.

Adult↗

Participation in breast cancer risk counseling among women with a family history.

Recent scientific breakthroughs in the genetics of breast cancer may have had effects on women's perceptions of risk and subsequent worry about breast cancer. Here, we present the rates of interest in counseling among women identified from diverse sources, their levels of cancer worry and perceived risk, and predictors of their agreement to participate in breast cancer risk counseling. Women were identified through breast cancer cases and through media offers. They completed a telephone survey and were ultimately either entered or not entered into a counseling trial. Overall, almost half (46%) of cases who were approached responded to the contact letter asking for information about potentially interested relatives. A total of 588 women responded to the brief media solicitations over a 15-week period. Participants recruited from media contacts reported slightly but significantly higher levels of worry about getting cancer, compared to case-recruited participants. Cancer worry negatively and significantly predicted entry into the counseling project. The results presented here may have implications for recruiting women in the general population with a family history of breast cancer for counseling about their risk for the disease.

Adolescent↗

Basal hormone levels in women who use acetaminophen for menstrual pain.

OBJECTIVE: To compare basal gonadotropin and estradiol levels between women using acetaminophen versus those using no or other types of analgesics. DESIGN: Observational study. SETTING: Three IVF clinics in greater Boston. PATIENT(S): Three hundred eighty-six women accepted for their first IVF treatment who completed questionnaires recording medical history, including analgesic use for menstrual pain, and who had blood drawn during the menstrual phase of a cycle before treatment. MAIN OUTCOME MEASURE(S): Basal FSH, LH, and estradiol. RESULT(S): Basal hormone levels, especially LH, were lower for women who regularly used acetaminophen compared with women who used no medication or other types of analgesics. Lower hormone levels in acetaminophen users were consistently observed when women were subdivided by age, body mass index, smoking history, and degree of menstrual pain-features that might have influenced analgesic use or hormone levels. CONCLUSION(S): This study provides preliminary evidence that acetaminophen may lower gonadotropin and estradiol levels and offers a biologic basis for the epidemiologic observation that acetaminophen use may reduce the risk of ovarian cancer.

Acetaminophen↗

Efficacy of zanamivir for chemoprophylaxis of nursing home influenza outbreaks.

Despite vaccination, influenza remains a common of morbidity in nursing homes. Chemoprophylaxis of residents with currently available antivirals is not always effective and new agents effective against both influenza A and B are needed. In a randomized, unblinded pilot study, we compared 14 day chemoprophylaxis with zanamivir, an antiviral which inhibits influenza neuraminidase, to standard of care during sequential influenza A and influenza B outbreaks in a 735 bed nursing home. Influenza A outbreaks were declared on 6/14 epidemic units. Sixty-five volunteers on four epidemic units were randomized to zanamivir and on two epidemic units, 23 volunteers were randomized to rimantadine. During the 14 days of prophylaxis, only four new febrile respiratory illnesses were detected. One volunteer receiving rimantadine prophylaxis developed laboratory-confirmed influenza. Influenza B outbreaks were declared on 3/14 epidemic units. Thirty-five volunteers on two epidemic units were randomized to zanamivir and 18 volunteers on one epidemic unit were randomized to no drug. During the 14 days of prophylaxis, only one new febrile respiratory illness was detected. One volunteer randomized to receive no drug developed laboratory-confirmed influenza. Zanamivir appears comparably effective to standard of care in preventing influenza-like illness and laboratory-confirmed influenza in nursing homes, but requires further testing.

Aged↗

A longitudinal comparison of tooth whitening resulting from dentifrice use.

The effect of twice-daily brushing with one of three different dentifrices (Arm & Hammer Dental Care, Arm & Hammer Dental Care Extra Whitening, Crest) on stain removal and tooth whitening was examined in 115 volunteers over a period of 12 weeks. The facial surfaces of 12 anterior teeth were assessed for stain using a published, modified version of a standard stain index. Whiteness was measured on teeth 8 and 9 using a single Vita Lumin-Vaccum Shade Guide for consistency. At baseline, the mean facial stain scores were significantly higher (p < 0.05-0.01) for both Arm & Hammer dentifrices than for Crest. In addition, the tooth shades, as indicated by the stain guide, specifically the b* values representing yellowness, were quantified using a Minolta spectrophotometer. Arm & Hammer Dental Care Extra Whitening formula was found to be significantly better than Crest at removing naturally occurring extrinsic stain. The difference between Arm & Hammer Dental Care Extra Whitening and Crest became significant (p < 0.01) after two weeks of use, and remained intact during the balance of the study, achieving p values of 0.0002 for at least one of the three assessed parameters (total stain, proximal, and facial) at weeks 4 and 12. The study also found that Arm & Hammer Dental Care produced a significant increase in tooth whiteness by week 12, whereas Crest showed no such increase at any time during the study. These results suggest that the two Arm & Hammer Baking Soda products are more effective in reducing stain and increasing whiteness than the standard silica-based dentifrice. Their effectiveness is not related to abrasivity since they are less abrasive to tooth enamel than the silica-based product tested.

Adolescent↗

Long-term treatment of a breastfeeding mother with fluconazole-resolved nipple pain caused by yeast: a case study.

This case follows a breastfeeding mother with cracked nipples undergoing antibiotic treatment (dicloxacillin) for mastitis. Nipple candidiasis also presented with burning, stinging pain radiating from the nipples into the breast, lasting throughout feedings and beyond. Over a 7-week period, the asymptomatic infant was treated with the oral antifungal, nystatin. After other antifungal treatment regimens (oral nystatin, tristatin ointment) had been deemed unsuccessful for the mother, the physician prescribed fluconazole (200 mg loading dose plus 100 mg/day for 15 days) which reduced, but did not eliminate, the nipple yeast and accompanying pain. Fluconazole was continued for an additional 30 days (200 mg/day) for a total of 6 weeks of treatment with this medication. Concurrently, a topical yeast medication (tristatin ointment) was used for a total of 8 weeks on the nipples/areola, after which the overt pain was resolved. Although the mastitis resolved after 1 week, the cracked nipples did not completely heal for several months. During the initial 3 weeks of treatment, neither over-the-counter pain medication nor acetaminophen with codeine relieved this mother's pain. Hydrocodone bitartrate and acetaminophen (10/650 mg/tablet) (Lorcet) offered the pain relief necessary for this mother to continue to breastfeed.

Antifungal Agents↗

Mechanisms of drug-induced lupus. II. T cells overexpressing lymphocyte function-associated antigen 1 become autoreactive and cause a lupuslike disease in syngeneic mice.

Current theories propose that systemic lupus erythematosus develops when genetically predisposed individuals are exposed to certain environmental agents, although how these agents trigger lupus is uncertain. Some of these agents, such as procainamide, hydralazine, and UV-light inhibit T cell DNA methylation, increase lymphocyte function-associated antigen 1 (LFA-1) (CD11a/CD18) expression, and induce autoreactivity in vitro, and adoptive transfer of T cells that are made autoreactive by this mechanism causes a lupuslike disease. The mechanism by which these cells cause autoimmunity is unknown. In this report, we present evidence that LFA-1 overexpression is sufficient to induce autoimmunity. LFA-1 overexpression was induced on cloned murine Th2 cells by transfection, resulting in autoreactivity. Adoptive transfer of the transfected, autoreactive cells into syngeneic recipients caused a lupuslike disease with anti-DNA antibodies, an immune complex glomerulonephritis and pulmonary alveolitis, similar to that caused by cells treated with procainamide. These results indicate that agents or events which modify T cell DNA methylation may induce autoimmunity by causing T cell LFA-1 overexpression. Since T cells from patients with active lupus have hypomethylated DNA and overexpressed LFA-1, this mechanism could be important in the development of human autoimmunity.

Animals↗

Long-term nipple shield use--a positive perspective.

This report describes ten cases in which silicone nipple shields were used for two weeks or longer. In nine of the cases, shields were used to help babies attach to the breast. These babies had struggled to attach to the areola because of suck problems or the mother's lack of protractility of breast tissue. In the tenth case, the shield was used because of extreme nipple soreness. All babies were off the shield by 3.5 months of age; nine were feeding directly from the breast. All weights were appropriate or above for the age of the infant at three weeks, two months and four months.

Breast Feeding↗

The Oxfordshire Head Injury Register.

This paper looks at the process of setting up a Head Injury Register whose aims are: (1) to identify reliably and rapidly patients who have sustained a head injury so that service can be offered to them; and (2) to obtain epidemiological data to identify needs and inform future service planning and development. The register records all cases of head injury in patients aged 16-65, regardless of severity, which present to hospital services in Oxfordshire whether or not admitted as inpatients. It was set up as part of a research project into the value of providing an early follow-up service for head injury patients. The paper highlights the difficulty of identifying these patients reliably. It details the administrative and technological problems encountered, together with some of their solutions.

Craniocerebral Trauma↗

Role of the CD6 glycoprotein in antigen-specific and autoreactive responses of cloned human T lymphocytes.

CD6 is a 130 000 MW T-cell surface glycoprotein that can deliver coactivating signals to mature T lymphocytes. Studies using monoclonal antibodies (mAb) have defined at least four epitopes on CD6, and distinct functional responses are elicited by mAb to the different epitopes. The function of CD6 is unknown. Multiple CD6 ligands are predicted, based on data that a soluble CD6 fusion protein precipitates at least three peptides. A cDNA clone for one of these ligands, termed activated leucocyte-cell adhesion molecule (ALCAM) has recently been isolated. In order to further characterize the role of CD6 in cell-cell interactions, we have examined the role of CD6 in a variety of responses by tetanus toxoid (TT) specific human T-cell clones. Anti-CD6 mAb UMCD6 (epitope 3) inhibits antigen-specific responses of such clones to TT, but not to the superantigen SEA. Responses of clones to nominal antigen are CD6-dependent using either peripheral blood mononuclear cells (PBMC) or macrophage-depleted E rosette negative cells as the antigen-presenting cell (APC) population. Furthermore, these clones made autoreactive with DNA methyltransferase inhibitors express increased CD6, and autoreactivity is inhibited by UMCD6. Taken together, the data suggests the existence of a functional CD6 ligand in peripheral blood which is expressed by APC, including cells other than macrophages. Interactions between CD6 and CD6 ligands may regulate both antigen specific and autoreactive responses of human T lymphocytes.

Antigen-Presenting Cells↗

Lymphocyte function-associated antigen 1 overexpression and T cell autoreactivity.

OBJECTIVE: To determine if DNA methylation inhibitors make T cells autoreactive by inducing lymphocyte function-associated antigen type 1 (LFA-1) (CD11a/CD18) overexpression. METHODS: T cell clones were treated with 3 distinct DNA methylation inhibitors or were stably transfected with a CD18 cDNA in a mammalian expression vector, and the effects on LFA-1 expression and activation requirements were examined. RESULTS: LFA-1 overexpression, caused by DNA methylation inhibitors or by transfection, correlates with the development of autoreactivity. CONCLUSION: LFA-1 overexpression may contribute to T cell autoreactivity.

Azacitidine↗

Phenotypic and functional similarities between 5-azacytidine-treated T cells and a T cell subset in patients with active systemic lupus erythematosus.

OBJECTIVE: Antigen-specific CD4+ T cells treated with DNA methylation inhibitors become autoreactive, suggesting a novel mechanism for autoimmunity. To test whether this mechanism might be involved in systemic lupus erythematosus (SLE), phenotypic markers for the autoreactive cells were sought. METHODS: Cloned normal T cells were treated with the DNA methylation inhibitor 5-azacytidine (5-azaC) and studied for altered gene expression. T cells from patients with active SLE were then studied for a similar change in gene expression, and cells expressing the marker were tested for autoreactivity. RESULTS: 5-azaC-treated normal T cells had increased CD11a (leukocyte function-associated antigen 1 alpha) expression relative to other membrane molecules. A T cell subset with similar CD11a expression was found in patients with active SLE. This subset contained cells that spontaneously lysed autologous macrophages, with a specificity similar to that of 5-azaC-treated cells.

Antigens, CD↗