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Biomedical subjects

D Waters

Publications and source records attributed to D Waters.

At least 55 records · Page 3Linked to original sources
PubMed1998

Hepatitis C virus infection in the mothers and infants cohort study.

OBJECTIVES: To estimate the hepatitis C virus (HCV) vertical transmission rate, the effect of potential risk factors, and the pattern of HCV antibody response and viremia in HCV-infected infants. STUDY DESIGN: The Mothers and Infants Cohort Study enrolled both human immunodeficiency virus (HIV)-seropositive and HIV-seronegative pregnant women at five obstetric clinics in New York City in a prospective cohort study between January 1986 and January 1991. HCV-infected mothers and their 122 offspring were followed-up for a minimum of 12 months for evidence of HCV infection as determined by persistent HCV antibodies or detection of HCV RNA by reverse transcription polymerase chain reaction. Comparisons among groups for categorical variables were performed using the Fisher's exact test. RESULTS: Seven (6%; 95% confidence interval, 2%-11%) of the 122 infants were HCV-infected. There was a tendency for increased risk of transmission with maternal viral and obstetrical factors, such as coinfection with HIV (7% vs 4%), high HIV viral load (13% vs 6%), HCV viremia (8% vs 3%), vaginal delivery (6% vs 0%), and female gender of offspring (8% vs 3%), although none of the associations reached statistical significance. After loss of maternal antibody, HCV antibody seroconversion occurred at a mean age of 26 months in 3 HIV-coinfected infants compared with 7 months of age in 4 HCV-infected HIV-uninfected infants. Serial samples showed that HCV RNA persisted in 6 infants for at least 18 to 54 months. CONCLUSIONS: Our study is in accordance with other studies that have shown low overall HCV vertical transmission risk and a trend toward higher risk with maternal risk factors such as HIV-coinfection or HCV viremia. A delay in infant HCV antibody response may be associated with HIV coinfection although larger studies are needed to confirm these findings.

AIDS Serodiagnosis↗
PubMed1998

DDK rates in the paediatric clinic: a methodological minefield.

There are substantial differences in the norms reported for speech diadochokinetic (DDK) rates among several published studies. These may well be due to differences in type of data used, methods of data collection and DDK rate calculation. Such differences doubtless also exist in the calculation of DDK rate in routine clinical assessment. Methodological problems in DDK rate measurement are identified and discussed and a detailed protocol for DDK measurement is described.

Adolescent↗
PubMed1998

Targeting speech processing strengths to facilitate pronunciation change.

This paper reports investigation and intervention with a 5 year old boy (AG) with unintelligible speech. Phonological analysis and psycholinguistic investigation allowed exploration of his speech processing strengths and difficulties as a basis for planning intervention. It was hypothesised that intervention which exploited his strengths, without focusing directly on his difficulties, would enable him to discover how to modify his pronunciation patterns. Significant positive changes had occurred by age 6 years.

Child, Preschool↗
PubMed1997

Rationale, design, and baseline characteristics of a trial comparing aggressive lipid lowering with Atorvastatin Versus Revascularization Treatments (AVERT).

This study describes the design, methodologic features, and baseline characteristics of an open-label randomized trial to determine whether aggressive lipid-lowering therapy with atorvastatin is an alternative to angioplasty or other catheter-based revascularization procedures in patients with significant coronary artery disease. Three-hundred forty-one patients with low-density lipoprotein (LDL) cholesterol > or = 115 mg/dl and > or = 1 defined narrowing of a major coronary artery were randomized to atorvastatin or the indicated catheter-based revascularization and conventional care (including lipid-lowering therapy if prescribed). Ischemic events are tracked for 18 months. The primary efficacy parameter is the incidence of an ischemic event, defined as 1 of the following: cardiovascular death, cardiac arrest, nonfatal myocardial infarction, the need for coronary bypass grafting or angioplasty, cerebrovascular accident, and worsening angina verified by objective evidence requiring hospitalization (including unstable angina).

Angioplasty, Balloon, Coronary↗
PubMed1997

Blood collection on filter paper: a practical approach to sample collection for studies of perinatal HIV transmission.

The use of dried blood spots lends itself to widespread application in large field studies, especially in remote areas. We present experience gained during a perinatal HIV transmission study in southern Africa in which dried blood spot samples were used for polymerase chain reaction (PCR) tests. In this study, 15,810 filter paper cards with dried blood spots were collected. Infants were seen at age 6 and 12 weeks, and PCR was routinely done in duplicate on each sample. Of 186 negative controls (infants born to HIV-negative women), two (1.1%) had a single strongly reactive PCR result; the repeated duplicates were both negative. In contrast, all 24 known positive samples were strongly positive in both tests. Results were available from 1,976 duplicate tests on 1,235 infants born to HIV-infected women. Based on the PCR result on a later sample, the positive predictive value was 97.6% if both replicates were strongly positive (absorbance: 0.8 OD450 U), 100% when one of the replicates was strongly positive, and 27% when one or both replicates were weakly positive (but none strongly positive). When both replicates were negative, the negative predictive value was > or = 96.2%. Thus, when a single HIV PCR test has a strongly positive result, the infant is very likely to be infected. A positive PCR result after age 1 month was 98.9% accurate in predicting antibody positivity after 15 months. Suggestions for sample collection, storage, and PCR testing are provided.

Blood Preservation↗
PubMed1997

Prognostic importance of scintigraphic left ventricular cavity dilation during intravenous dipyridamole technetium-99m sestamibi myocardial tomographic imaging in predicting coronary events.

Left ventricular (LV) cavity dilation during stress myocardial perfusion imaging has been associated with multivessel disease, and may be an independent prognostic marker in addition to perfusion defects. The present study examines the predictive value for future cardiac events of transient or fixed LV dilation during dipyridamole technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) imaging. The study included 512 consecutive patients who underwent SPECT imaging with Tc-99m sestamibi after dipyridamole infusion. Transient LV dilation was seen in 70 patients (14%) and 74 had fixed cavity dilation (14%); cavity size was normal in 368 patients (72%). Each perfusion scan was classified as normal or abnormal, and if abnormal, defects were categorized as transient or fixed, and as small, medium, or large (depending upon the number of abnormal vascular territories). Events during a mean follow-up of 12.8 +/- 6.8 months were tabulated by direct review of hospital charts and death certificates. The cardiac event rate (cardiac death or nonfatal infarction) was 1.9% in patients with normal cavity size, 11.4% with transient LV dilation, and 13.5% with fixed LV dilation (p < 0.01). Compared with patients with normal cavity size, those with transient LV dilation were more likely to sustain a myocardial infarction (p < 0.01) and those with fixed dilation more frequently suffered cardiac death (p < 0.01) and hospitalization for heart failure (p < 0.01). The group with the highest risk had both a large perfusion defect and cavity dilation. By Cox proportional hazard regression analysis, both transient and fixed LV dilation were strong independent predictors of cardiac events. Transient or fixed LV dilation are commonly seen during dipyridamole Tc-99m sestamibi SPECT imaging (14% incidence for each) and are useful predictors of cardiac events.

Aged↗
PubMed1997

Influence of other maternal variables on the relationship between maternal virus load and mother-to-infant transmission of human immunodeficiency virus type 1.

To assess the relationship between maternal human immunodeficiency virus (HIV) type 1 RNA level, other important covariates, and mother-to-infant (vertical) transmission of HIV-1, third trimester repository specimens from 160 HIV-1-seropositive women enrolled in the Mothers and Infants Cohort Study between 1986 and 1991 were assayed in batch for HIV-1 RNA. A significant association between peripheral blood HIV-1 RNA level and vertical transmission remained after controlling for CD4 cell level, duration of ruptured membranes, "hard" drug (cocaine and heroin) use, and frequency of sexual activity during pregnancy. However, the association was attenuated among women with advanced HIV infection and those with a high frequency of sexual activity during pregnancy. In these settings, interventions that target risk factors other than virus load may be particularly important for preventing vertical transmission of HIV-1.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Does umbilical cord blood polymerase chain reaction positivity indicate in utero (pre-labor) HIV infection?

OBJECTIVE: To compare risk factors for infants whose cord blood was positive for HIV DNA with those who were cord blood-negative but found to be HIV DNA-positive in early infancy. METHODS: In 1994, infants born to HIV-infected women were enrolled in a study in Blantyre, Malawi. Birth weight and transmission risk factors from cord blood-positive infants were compared with cord blood-negative/HIV-positive infants on their first postnatal visit (4-7 weeks of age). Testing for HIV DNA on cord and peripheral blood was performed by polymerase chain reaction. RESULTS: Of 249 HIV-infected infants (overall transmission rate, 26%), 83 (33%) were cord blood-positive and 166 were initially cord blood-negative. The mean birth weight was 2.1% (59 g) lighter in cord blood-positive infants than initially cord blood-negative infants; initially cord blood-negative infants were 2.8% (80 g) lighter than uninfected infants born to HIV-infected women. There were no significant differences in the risk factors for infection between HIV-infected cord blood-positive and -negative infants; when transmission was increased, both HIV-infected cord blood-positive and -negative infants contributed to the increase in a similar proportion. INTERPRETATION: It was concluded that umbilical cord blood positivity for HIV DNA did not identity a subset of in utero HIV-infected infants and suggested that HIV-infected cord blood-positive and -negative infants have similar timing and routes of HIV infection.

Adolescent↗
PubMed1997

Structure of a primary care support system to coordinate comprehensive care for children and families infected/affected by human immunodeficiency virus in a managed care environment.

BACKGROUND: Children with HIV infection require coordinated primary and tertiary care. OBJECTIVES: To describe the structure of the Wisconsin HIV Primary Care Support Network, a decentralized program for care of children and families infected or affected by HIV infection. METHODS: Review of data concerning all children with HIV infection included in the Network's database. RESULTS: In this Network centralized HIV specialists work with primary care practitioners throughout Wisconsin to assure that children with HIV infection have access to care of uniform quality no matter where they live. Network staff care for children with HIV infection both directly and through the education and support of primary care providers. Care requirements are outlined in a state-published protocol supplied to practitioners. Audit of care is possible because of a centralized data collection system, and ongoing feedback and education occur via the activities of nursing care coordinators and both hospital- and community-based social workers. CONCLUSIONS: This system of care may serve as a model for care delivery to children with HIV infection in low prevalence areas and may be applicable to the care of children with other chronic diseases being cared for in a managed care environment.

Adult↗
PubMed1997

Interlaboratory agreement among results of human papillomavirus type 16 enzyme-linked immunosorbent assays.

Serological assays for measuring antibodies to human papillomavirus type 16 (HPV-16) virus-like particles (VLPs) have become important epidemiologic tools in recent years. However, the interlaboratory replicability of these assays has not been assessed. In this investigation, three laboratories tested a panel of specimens obtained from two different groups: 265 subjects in a vulvar cancer case-control study and 107 healthy volunteer blood donors. Each laboratory used an enzyme-linked immunosorbent assay (ELISA), but no attempt was made to standardize assay procedures among the three laboratories. The data showed good day-to-day intralaboratory replicability in laboratory 1 (correlation coefficient, > or = 0.88) and good intra-assay variability in laboratory 3 (correlation coefficient, > or = 0.93). Interlaboratory correlations, likewise, ranged between 0.61 and 0.80 in both case-control study subjects and healthy blood donors, indicating that ELISA optical density (OD) values between laboratories were linearly related regardless of the population. Kappa coefficients (kappa), based on each laboratory's categorical interpretation of its results (as positive or negative), showed good agreement (kappa, > 0.6) in case-control study subjects and moderate agreement (kappa, > or = 0.4) in blood donors, a population that had few strongly positive sera. When OD values near seropositive cutoffs were treated as indeterminates, there was little discordance between laboratories in either population. The data suggest that each laboratory measured the same humoral immune response and that their HPV-16 VLP ELISAs performed similarly (Pearson correlations). Interlaboratory differences, however, probably due to reagents and procedures, were considerably greater than intralaboratory day-to-day variability. Interlaboratory agreement in determining seropositivity (kappa) could be improved by sharing positive and negative serum controls and by treating marginal results as indeterminate. As part of continuing cooperation to improve interlaboratory agreement, we are preparing bulk serum control specimens to be shared and made available to interested researchers.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

Coronary stent placement as a bridge to coronary artery bypass surgery in an unstable, anemic Jehovah's Witness patient: a case report and review of bloodless surgery techniques.

Bloodless cardiac surgery would be optimal for all patients undergoing major or complex heart surgery; however, for Jehovah's Witnesses it involves a religious law and is fundamentally mandated. In this context, we review a case of unstable angina with associated anemia requiring catheterization and definitive intervention in a Jehovah's Witness patient. Coronary stenting to stabilize the acute coronary syndrome is described with definitive total revascularization performed by coronary artery bypass graft surgery after utilizing erythropoietin and aggressive blood conservation techniques.

Aged↗
PubMed1997

Relationship between atypical adenomatous hyperplasia (AAH), prostatic intraepithelial neoplasia (PIN) and prostatic adenocarcinoma.

Two histopathologic lesions are considered putative precursors of prostate cancer, but the supportive evidence for one (prostatic intraepithelial neoplasia, or PIN) is much greater than the other (atypical adenomatous hyperplasia, or AAH). High grade PIN is the most likely precursor of carcinoma, arising in the peripheral zone, but probably does not account for well-differentiated cancer arising in the transition zone. The biological significance of atypical adenomatous hyperplasia of the prostate (AAH) is inconclusive at the time. The histological and cytological features of AAH are intermediate between BPH and low grade carcinoma, suggesting that AAH may be a precursor of well differentiated transition; zone carcinoma. In the recent time new findings on morphogenetic aspects of normal and abnormal prostatic growth i.e. stem cell models are discussed and topics about grading and proliferative activities, frequency and histological changes associated with aging as well as clinical relevance of PIN and AAH. This paper reviews the results and discussion at the second international consultation meeting on PIN in Mayo Clinic, Rochester, Nov. 3-4 th. 1995, following the first international consultation meeting of AAH and PIN and origin of the prostatic carcinoma in Ancona, Sept. 11-12 th 1994.

Adenocarcinoma↗
PubMed1997

Calcium channel blockers: an evidence-based review.

Calcium channel blockers are widely used in the treatment of cardiovascular disease, but their proper therapeutic role is controversial. Nevertheless, drugs from this class have been evaluated in many controlled clinical trials of adequate size and duration in different patient populations. Although many important questions remain unanswered, these trials have clarified when and how these drugs should be used. In general, the benefits of calcium channel blockers in controlling angina and hypertension are much more clearly documented than are their long term effects on harder end-points such as mortality. Such long term data are sorely needed, particularly for hypertension. An increased risk with dihydropyridine calcium channel blockers has been clearly seen across several studies of patients with coronary disease. In coronary patients with heart failure, the deleterious effects of nifedipine, diltiazem and verapamil outweigh any possible benefit. Long acting formulations and newer calcium channel blockers may not share all of the adverse effects of the older drugs of this class; however, their long term safety has not yet been documented. An understanding of the limitations of calcium channel blockers, based upon clinical trial evidence, often leads the practitioner to choose a drug from another class, where efficacy has been clearly proven.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1996

Recombinant human growth hormone, insulin-like growth factor 1, and combination therapy in AIDS-associated wasting. A randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To increase lean body mass and improve health status in patients with wasting associated with the acquired immunodeficiency syndrome (AIDS) by treatment with recombinant human growth hormone (rhGH), recombinant human insulin-like growth factor 1 (rhIGF-1), or both. DESIGN: Randomized, double-blind, placebo-controlled clinical trial. SETTING: University of New Mexico Clinical Research Center and University of Texas Southwestern Medical Center. PATIENTS: 60 patients with AIDS and wasting as defined by the Centers for Disease Control and Prevention. Patients were divided into four groups of 15 patients each. INTERVENTION: Group 1 received 1.4 mg of rhGH once daily plus placebo twice daily; group 2 received 5 mg of rhIGF-1 twice daily plus placebo once daily; group 3 received 5 mg of rhIGF-1 twice daily plus 1.4 mg of rhGH once daily; and group 4 received placebo three times daily. MEASUREMENTS: Body weight, body composition, muscle strength, protein catabolism, quality of life, and immune status were assessed at baseline, and changes in these variables were measured at 6 and 12 weeks. RESULTS: At 6 weeks, lean body mass had increased and total fat mass had decreased in the groups receiving rhGH, rhIGF-1, or both. Group 3 had the greatest changes in lean body mass (mean +/- SE, 3.2 +/- 0.59 kg; P < 0.001); only in this group were changes in body mass maintained at 12 weeks. Only patients in group 1 had improvement in muscular strength of the knees and upper body (P = 0.04) and quality of life (P = 0.01). Immunologic function did not improve in any group. CONCLUSIONS: Growth factor therapy had significantly increased lean body mass and decreased fat mass by 6 weeks, but these improvements persisted for 12 weeks only in group 3. Growth factor therapy at the dosages used in this study is not recommended because the magnitude of weight gain was modest and improvements in quality-of-life measures varied.

Adult↗