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Biomedical subjects

H A Williams

Publications and source records attributed to H A Williams.

At least 19 recordsLinked to original sources
PubMed2003

Trends in antimalarial drug deployment in sub-Saharan Africa.

Antimalarial drug resistance is forcing newly developed pharmaceuticals into widespread use at an accelerating pace. To have the greatest public health impact, new pharmaceuticals will need to be deployed effectively in sub-Saharan Africa. Achieving effective antimalarial drug deployment over the short- to medium-term will require an appreciation of how drugs are currently used in Africa and the development of innovative approaches to optimize that use. Over the long-term, fundamental changes in the way that drugs are deployed will probably be required. There are many new strategies and initiatives that, to a greater or lesser degree, will influence how drugs are used. These influences may have a positive or negative effect on reducing malaria morbidity and mortality. The concept of analyzing and monitoring programmatic effectiveness allows for a more holistic understanding of these influences and allows for more unbiased, evidence-based decision making related to drug policy and deployment.

Africa South of the Sahara↗
PubMed2000

Surfactant transport over airway liquid lining of nonuniform depth.

Numerous effects (e.g., airway wall buckling, gravity, airway curvature, capillary instabilities) give rise to nonuniformities in the depth of the liquid lining of peripheral lung airways. The effects of such thickness variations on the unsteady spreading of a surfactant monolayer along an airway are explored theoretically here. Flow-induced film deformations are shown to have only a modest influence on spreading rates, motivating the use of a simplified model in which the liquid-lining depth is prescribed and the monolayer concentration satisfies a spatially inhomogeneous nonlinear diffusion equation. Two generic situations are considered: spreading along a continuous annular liquid lining of nonuniform depth, and spreading along a rivulet that wets the airway wall with zero contact angle. In both cases, transverse averaging at large times yields a one-dimensional approximation of axial spreading that is valid for the majority of the monolayer. However, a localized monolayer remains persistently two dimensional in a region at its leading edge having axial length scales comparable to the length scale of transverse depth variation. It is also shown how the transverse spreading of a monolayer may be arrested as it approaches a static contact line at the edge of a rivulet. Implications for Surfactant Replacement Therapy are discussed.

Biological Transport, Active↗
PubMed2000

Mosquito collections following local transmission of Plasmodium falciparum malaria in Westmoreland County, Virginia.

A 63-year-old woman from Colonial Beach, Westmoreland County, VA, was diagnosed with Plasmodium falciparum malaria on July 19, 1998. The woman had no history of international travel, intravenous drug use, blood transfusion, or other risk factor for contracting the disease. She seldom left the county and generally spent her evenings indoors, leading to the conclusion that she had been bitten locally by an infected mosquito. Colonial Beach is host to a population of migrant agricultural laborers from areas in which malaria occurs, but a blood survey of 89 Haitians and Mexicans failed to find Plasmodium parasites, specific antibodies, or clinical cases of malaria. Mosquito surveys were conducted during 2 days (July 22 and 28, 1998) with carbon-dioxide-baited light traps, larval and pupal collections, and landing collections. Thirteen species of mosquitoes were identified morphologically, including 4 potential vectors: Anopheles crucians, An. punctipennis, An. smaragdinus (new state record), and An. quadrimaculatus s.s. (new state record). Identifications of the latter 2 species were confirmed by sequencing of the ITS2 DNA region from adults reared from locally collected larvae. Anopheles smaragdinus was the most common biting species among the potential vectors, although An. crucians was the most abundant in other kinds of collections. In addition, Ae. albopictus was collected in Westmoreland County for the 1st time.

Aedes↗
PubMed1999

Malaria surveillance--United States, 1995.

PROBLEM/CONDITION: Malaria is caused by four species of Plasmodium (i.e., P. falciparum, P. vivax, P. ovale, or P. malariae), which are transmitted by the bite of an infective female Anopheles sp. mosquito. Most malaria infections in the United States occur among persons who have traveled to areas with ongoing transmission. Occasionally, cases occur in the United States through exposure to infected blood products, by congenital transmission, or by local mosquito-borne transmission. Malaria surveillance is conducted to identify episodes of local transmission and to guide prevention recommendations for travelers. REPORTING PERIOD: Cases with onset of illness during 1995. DESCRIPTION OF SYSTEM: Malaria cases confirmed by blood smears are reported to local and/or state health departments by health-care providers and/or laboratory staff. Case investigations are conducted by local and/or state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System (NMSS). Data from NMSS serve as the basis for this report. RESULTS: CDC received reports of 1,167 cases of malaria with onset of symptoms during 1995 among persons in the United States or one of its territories. This number represents an increase of 15% from the 1,014 cases reported for 1994. P. vivax, P. falciparum, P. malariae, and P. ovale were identified in 48.2%, 38.6%, 3.9%, and 2.2% of cases, respectively. More than one species was present in three patients (0.3% of total). The infecting species was not determined in 80 (6.9%) cases. The number of reported malaria cases acquired in Africa (n=519) remained approximately the same as in 1994 (n=517); cases acquired in Asia increased by 32.4% (n=335); and cases acquired in the Americas increased by 37.4 % (n=246). Of 591 U.S. civilians who acquired malaria abroad, 15.6% had followed a chemoprophylactic drug regimen recommended by CDC for the area where they had traveled. Nine patients became infected in the United States. Of these nine cases, five were congenitally acquired; one was acquired by organ transplantation; and one was acquired by a blood transfusion. For two of the nine cases, the source of infection was unknown. Six deaths were attributed to malaria. INTERPRETATION: The 15% increase in malaria cases in 1995 compared with 1994 resulted primarily from increases in cases acquired in Asia and the Americas, most notably a 100% increase in the number of cases reported from South America. This change could have resulted from local changes in disease transmission, travel patterns, reporting errors, or a decreased use of effective antimalarial chemoprophylaxis. In most reported cases, U.S. civilians who acquired infection abroad were not on an appropriate chemoprophylaxis regimen for the country where they acquired malaria. ACTIONS TAKEN: Additional information was obtained concerning the six fatal cases and the nine infections acquired in the United States. Malaria prevention guidelines were updated and distributed to health-care providers. Persons traveling to a malarious area should take the recommended chemoprophylaxis regimen and use personal protection measures to prevent mosquito bites. Any person who has been to a malarious area and who subsequently develops a fever or influenza-like symptoms should seek medical care; investigation should include a blood smear for malaria. Malaria infections can be fatal if not diagnosed and treated promptly. Recommendations concerning prevention and treatment of malaria can be obtained from CDC.

Humans↗
PubMed1999

A community perspective on the efficacy of malaria treatment options for children in Lundazi district, Zambia.

In 1996, Zambia's Ministry of Health made sulfadoxine-pyrimethamine (SP) available as a second-line antimalarial. SP differs from chloroquine (CQ) in ways that might affect parents' acceptance of the drug, resulting in possible delays in seeking treatment if parents perceive SP as less efficacious. A multifaceted study consisting of a rapid community ethnographic assessment to examine local attitudes and perceptions toward malaria, a 14-day in vivo drug efficacy study comparing clinical and parasitological efficacy of CQ, SP, and SP with paracetamol (PCM) in children under five, and a qualitative study examining caretakers' perceptions of drug efficacy helped to guide implementation of the new drug policy. The rapid ethnographic study indicated that the community was aware of malaria as an illness best treated with modern medicines, particularly CQ. The drug efficacy study demonstrated a 25% level of clinical failures compared to none with SP, and 30% of the children treated with CQ had either RIII or RII parasitological failures whereas none occurred in children treated with SP. Most parents perceived that their children were improving and that the drugs were working. Parents in the SP groups were most pleased and readily accepted SP as a new drug. The addition of PCM did not improve perceptions of SP efficacy, contradicting conventional wisdom regarding the need for direct antipyretic action for parents to perceive a drug as efficacious. The combined results reflected a community that was in the beginning stages of evaluating a new malaria therapy mostly unknown to them. Perceptions of efficacy of CQ were beginning to shift, indicating a readiness for accepting a new drug based on its shown biological efficacy. Parasitological and clinical failure rates reinforced the need to fully implement the changed national policy as soon as possible, and to consider a change in first-line therapy.

Antimalarials↗
PubMed1996

Reproductive decision-making and determinants of contraceptive use in HIV-infected women.

Perinatal transmission and reproductive decisions of HIV-infected women can be categorized in statistical and epidemiological terms. These reports and figures, however, do little to fully explain the complexities of human relationships, life experiences, personal and cultural influences, and situational and environmental variables that impact on the HIV-infected woman regarding reproductive decision-making. It is only with genuine attempts to understand the woman's perspective and the dynamic and unique variables that influence reproductive decision-making, as well as maintaining a non-judgmental and culturally sensitive perspective, can we hope to assist women, and society as a whole, in coming to terms with the complexities of HIV and reproductive decision-making. Further study is needed to identify factors that influence reproductive decision-making in HIV-infected women. The determinants of contraceptive use regarding demographic factors, barriers to contraceptive use, and factors that contribute to successful contraceptive use in this population must be understood if efforts to reduce the number of unplanned pregnancies are to be successful. More conclusive data are needed on the safety and efficacy of oral contraceptives in HIV-infected women as well as data that describe the effects of longer acting hormonal contraceptives such as levonorgestrel implants (Norplant; Wyeth-Ayerst, Philadelphia, PA) and injectable medroxyprogesterone acetate (Depo Provera; Upjohn Company, Kalamazoo, MI). More research is needed to determine the effects of patient education and counseling and closer follow-up on effective long-term contraception in HIV-infected women.

Contraception↗
PubMed1996

The silent ones: a review of sampling issues and biases pertinent to the area of pediatric oncology procedural pain.

Pain related to procedures for pediatric oncology patients is a salient topic. Although these procedures can cause much distress, this area has been neglected in research. Previous research has suffered from serious sampling problems, such as using small, nonrepresentative, biased samples. In addition, little is known about the influence of sociocultural factors on the phenomena of pain in children. This article presents the results of a review of the past 10 years of pertinent literature, argues that sociocultural influences on pain need to be studied, and offers suggestions for improving sampling designs.

Child↗
PubMed1995

Certification of pediatric oncology nurses: from roundtable discussion to reality.

Certification for pediatric oncology nurses became a reality in 1993 when the first national certification examination was administered in Reno, NV. Some members of the Association of Pediatric Oncology Nursing initially voiced an interest in certification at a roundtable discussion held during the 1988 annual meeting. The momentum lead to the formation of a task force to initiate the certification process. The task force led to an ad hoc committee, organized to design and implement certification. Certification is now overseen by the Certification Corporation of Pediatric Oncology Nurses. The benefits of certification and a historical overview of pediatric oncology nursing certification is discussed in this article. Details of how the test was designed are offered, as well as results from the pilot study. This article concludes with data from the first examination.

Certification↗
PubMed1995

Treating ankylosed primary teeth in adult patients: a case report.

When ankylosed primary teeth are retained beyond the mixed-dentition stage and the involved teeth are below the occlusal plane, occlusal and interproximal contacts can be restored to esthetic and functional anatomic contours. With the development of new, improved posterior composite resins that have greater wear resistance and stronger adhesive bonding systems for enamel and dentin, new opportunities for conservative, simple, and efficient esthetic and functional restorations are possible in selected retained ankylosed primary molars.

Acrylates↗
PubMed1993

A comparison of social support and social networks of black parents and white parents with chronically ill children.

Characteristics of social networks and provision of support were examined for two groups of parents of chronically ill children, one group black and one group white. Black and white parents both reported similarities in the experience of parenting a child with a chronic illness. Both sets of parents relied primarily on family networks to provide much needed support. White networks were twice as large as black networks, although black parents perceived the individuals in their networks as being more supportive. For both groups, the networks were of long duration. Network members were geographically closer to blacks. White parents discussed support mostly in terms of affect. Black parents described support as instrumental actions. Differences in income levels between blacks and whites might account for differing descriptions of support. The experience of having a chronically ill child appears to override racism in the health care system. Black parents did not perceive any problems, based on race, that affected receiving medical care for their children.

Adult↗
PubMed1993

Searching the literature creatively: updating your skills in reviewing the literature.

Reviewing the literature is not only an essential aspect of research, it can be a creative process. Computerized searches decrease the hours that searches formerly took and allow the researcher to link concepts in ways that were previously difficult to do. Be consistent with your approach to reviewing the literature and your reward will be a comprehensive overview of the extant literature--an excellent start to validating your research project.

Abstracting and Indexing↗
PubMed1992

Comparing the perception of support by parents of children with cancer and by health professionals.

Childhood cancer is considered one of the greatest challenges a family can face. Some families cope well with it; others do not. The presence of social support, both perceived and actual, as well as the individuals with whom parents interact, may determine how well a family copes. The purpose of this pilot study was to describe how parents of children with cancer perceive support and the types of things parents found supportive while their child was hospitalized. Parents' perceptions of support were compared with those of the health professionals involved in the care of these children. The primary way the parents perceived support was any activity that met their affective needs. Health professionals faltered when asked to define support, but most said that it meant "being available." Caring and educational activities were the two ways the professionals could offer support to the families, yet parents rarely mentioned teaching as a supportive activity. Parents and health professionals defined aspects of support similarly, but there was minimal congruity between them in listing which people were considered supportive to the parents. In conclusion, health professionals and parents have similar ideas about what support is, but at best, the professionals' predictions concerning who is supportive in a given case appear random and may be biased. This study suggests that new ways of assessing support needs for these families are needed.

Adolescent↗
PubMed1992

Bleaching the natural dentition to match the color of existing restorations: case reports.

Vital tooth bleaching has become a popular and successful treatment. This treatment may be performed under controlled conditions in the dental office or it may be used under monitored, prescribed conditions with a 10% or 15% carbamide peroxide solution, applied by the patient at home. This paper presents the use of both types of systems in a unique application to modify the color of the natural dentition to match that of existing restorations.

Adult↗
PubMed1992

Retention strengths of three cements using full crown preparations restored with amalgam.

The tensile bond strength of noble and non-noble castings luted with adhesive resin cements and zinc phosphate cement to prepared extracted teeth having received MOD amalgam restorations were compared. The crown preparations were standardized on the extracted teeth to produce axial wall length and taper consistent with that seen clinically. Results indicated the resin luting agents were significantly more retentive than the zinc phosphate cement and for each cement there was no difference in the casting alloy used.

Analysis of Variance↗
PubMed1991

Spatial realignment using the hybrid resin-bonded bridge.

As an alternative to a conventional fixed partial denture, a modification of the hybrid resin-bonded bridge was used to compensate for a spatial discrepancy accentuated by a missing tooth. The proximal margins of the restoration were extended onto the facial surfaces of the abutment teeth to create a partially veneered surface. The abutment teeth were widened by shifting the embrasure into the edentulous space, thus creating more esthetic proportions.

Cementation↗
PubMed1990

Definitions of normal alcohol consumption held by male University of Zimbabwe senior year medical students.

A structured questionnaire designed to assess the definition of the normal, non-problem use of Western type alcohol for the average male and the average female was administered to 40 Black male University of Zimbabwe 4th- and 5th-year medical students. The students' definition of the normal, non-problem use of alcohol was established for the average male and the average female. The students defined it as normal for males to drink significantly more alcohol than females.

Adult↗
PubMed1989

Sexuality in children and adolescents with cancer: pediatric oncology nurses' attitudes and behaviors.

It is essential that health professionals openly discuss how cancer may affect the developing sexuality of childhood cancer patients. This study was conducted to explore nurses' attitudes and behaviors regarding sexuality in cancer patients. Results are reported for a subset of a larger study (N = 937) from subjects who indicated that their practice included children and/or adolescents (N = 156). The Williams-Wilson Sexuality Survey was used to measure attitudes towards sexuality in cancer patients, behavior in nursing care related to the sexuality of a cancer patient, and attitudes towards sexuality in the child and/or adolescent with cancer. The majority of subjects agreed that sexuality should be a routine component of nursing care, yet less than half had actually discussed an alternation in sexuality with an adolescent patient. More than one third said they were not comfortable in initiating such discussions. However, they were comfortable in discussing sexuality concerns when these discussions were initiated by the patient and/or family.

Adolescent↗