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Biomedical subjects

D Webster

Publications and source records attributed to D Webster.

At least 73 records · Page 4Linked to original sources
PubMed1987

Detection of human immunodeficiency virus by reverse transcriptase assay, antigen capture assay, and radioimmunoassay.

The reverse transcriptase assay, antigen capture assay, and radioimmunoassay were compared for the detection of human immunodeficiency virus (HIV) in culture fluids of virus-infected lymphocytes. The reverse transcriptase assay and the antigen capture assay were compared for 962 samples, and the two tests displayed comparable sensitivities (98.5% agreement) in detecting HIV antigen. In addition, these two tests displayed similar sensitivities when examined for the kinetics of HIV appearance following in vitro infection of normal lymphocytes. We also found the antigen capture assay to be as sensitive as the radioimmunoassay in detecting HIV antigen in culture fluids. Furthermore, all three tests were found to be reasonably concordant when applied simultaneously to the detection of HIV antigen in cultures. The antigen capture assay, however, is relatively fast, can handle a large number of samples, does not require radioactive material, and is less expensive than the other two tests. Therefore, the antigen capture assay appears to be the method of choice for the detection of HIV in routine virus culturing.

Antigens, Viral↗
PubMed1986

Pregnancy in a drug-abusing population.

Substance abuse in pregnancy places both mother and infant at extremely high risk. There is little information, however, about the impact of changing patterns of drug use and improvements in medical technology on pregnancy outcome. The Family Center Program utilizes a team approach to provide counseling, support, and education as well as complete medical care for substance-abusing pregnant women. We reviewed the records of women seen in the Family Center Program from 1981 to 1983 to evaluate the effect of intervention on pregnancy outcome. Complications, including prematurity, growth retardation, intrauterine fetal demise, and neonatal abstinence, were common, although early prenatal care and frequent visits appear to reduce the risk of low birth weight infants. Uncorrected perinatal mortality was 11/163 (67/1,000). Compared to earlier experience in this program, few women delivered with no prenatal care. Thus a program designed specifically for the needs of these women is successful in increasing the number seeking prenatal care and appears to improve pregnancy outcome. Despite this, serious problems are common and further improvement seems unlikely unless such women can be maintained in a stable, drug-free environment during their pregnancies.

Adult↗
PubMed1986

Women's health. Changing definitions; changing times.

The implications of the above observations and questions are far from prescriptive. During this time of rapid social change and economic retrenchment, there is a need for both individual and professional clarification of values. An awareness of one's philosophy of life and philosophy of nursing requires constant re-evaluation and may reflect personal developmental changes, changes within nursing, and changes in social demands. Woods' schema for evaluating health phenomena by considering variables in context and with an awareness of developmental dimensions might well be used as a model for such personal and professional self-evaluation. It is only following such efforts that it will be possible to make knowledgeable decisions about the relationship between philosophy and public policy, personal/private behavior, and public/social consequences. Social change is invariably accompanied by a disquieting ambivalence. Whether one agrees with the philosophies of the women's health movement, one fact is clear. Change has occurred and it is no longer possible to ignore the paternalistic tendencies within the health care field. When lay magazines proclaim that the women's health movement is in the forefront of the consumer movement, it behooves all health care professionals to be aware that consumers will be seeking more information, more power in decision making, and will expect professionals to share responsibility for the development of treatment plans and for the evaluation of such treatments. Consumers and nurses can be expected to continue to demand that their experiences and perspectives be valued and taken into consideration.

Education, Nursing↗
PubMed1986

Women and mental health. A model for practice.

This article has addressed the need to consider multiple sources of stress in women's lives to assist them in determining those areas over which they can increase their sense of control as well as ways of coping with those aspects over which they have limited control. The continuing need to help women define and explore realistic options is stressed.

Adolescent↗
PubMed1985

Effect of fixation devices on radiostrontium clearance in the intact canine femur.

Femoral metaphyseal/diaphyseal blood flow was studied by 85Sr clearance in unfractured segments of dog femurs following compression plating and various control procedures (drilling with and without application of screws). The animals were tested as early as seven days and as late as two months after surgery. The only statistically significant change in strontium clearance (SrC) was an increase produced by the application of stainless-steel bone screws, with or without plates. The presence or absence of compression had no consistent effect on changes in the rate of SrC. During the period of study, no changes in bone mineralization, haversian porosity, or cortical bone thickness accompanied the SrC alterations.

Animals↗
PubMed1984

Determination of HDL-cholesterol using 2,4,6-tribromo-3-hydroxybenzoic acid with a commercial CHOD-PAP reagent.

The Boehringer one-component high-performance cholesterol oxidase reagent has been modified by the inclusion of 2,4,6-tribromo-3-hydroxybenzoic acid (TBHBA) to give a fourfold increase in sensitivity to a molar absorbance of approximately equal to 29,000 with respect to cholesterol. The resulting reagent system is particularly suitable for the determination of plasma HDL-cholesterol for which a reagent of high sensitivity is required. A simple method of bromination avoiding the use of elemental bromine is used to prepare TBHBA. The modified reagent system has been found to have good within- and between-batch precision and has shown itself to be reliable and trouble-free.

Bromobenzoates↗
PubMed1983

The effect of protracted tetracycline treatment on bone growth and maturation.

Mature female rhesus monkeys were used to evaluate the effects of a one-year course of tetracycline (50 mg/kg/day, intramuscularly) on the formation, maturation, and mineralization of mandibular bone. The bones from the treated group contained normal concentrations of calcium (Ca), inorganic phosphorus (Pi), and hydroxyproline (HO-Pr), and the treatment schedule did not alter the distribution (percentage) of total osteons into slightly, moderately, and highly mineralization classes. Tetracycline impairs bone mineralization and the subsequent maturation of the mineral and matrix moieties. The percentage of highly mineralized osteons labeled with tetracycline is subnormal. Density gradient fractionation studies indicate the presence of abnormally high Ca/Pi ratios in the temporally young newly formed bone mineral and somewhat higher ratios in the most mature bone fraction. Protracted tetracycline treatment at high dosages impairs bone growth and maturation in adult rhesus monkeys.

Animals↗
PubMed1983

Healing of canine femoral osteotomies. Effects of compression plates versus Eggers' plates.

The effects of rigid self-compressing plates were compared with the effects of less rigid internal contact splints on the healing characteristics of osteotomized canine femora. Radiographically, the rigid fixation afforded by the compression plate produced accelerated healing as compared with the less rigid fixation obtained with splints at two to four months. At six months there was little or no difference between the two groups. Comparison of the material biomechanical properties of the healing femora suggested that the repair tissue formed early after compression plating was stronger than the callus tissue that surrounded the less rigidly fixed femora. A comparison of the structural biomechanical properties of the bones suggested, conversely, that a stronger whole bone resulted from the less rigid fixation splint. The histomorphometric data showed that some cortical bone was lost under both types of fixation plates. However, the patterns of loss were not comparable. Use of rigid internal fixation led to loss of cortical bone after four to six months, while the less rigid fixation obtained with the Eggers splint produced mild intracortical resorption only. These observations point to the desirability of rigid internal fixation early in the healing process and the possible benefit of decreasing the rigidity of the fixation device as healing proceeds.

Animals↗
PubMed1982

Immature B cells in fetal development and immunodeficiency: studies of IgM, IgG, IgA and IgD production in vitro using Epstein-Barr virus activation.

Epstein-Barr virus has been used as a B cell mitogen to explore the parallels between the B cells found in patients with hypogammaglobulinemia and the immature B cells in fetal tissues. Peripheral blood lymphocytes from 29 cases of late onset hypogammaglobulinemia (common variable immunodeficiency) and from 10 cases of X-linked hypogammaglobulinemia were depleted of T lymphocytes and stimulated with virus in vitro. Immunoglobulin production was measured over a 4-week culture period using inhibition radioimmunoassays for IgM, IgG, IgA and IgD. The results were compared with those seen with fetal liver cells, cord blood lymphocytes and adult lymphocytes. Virus-stimulated cells from fetal sources produced small amounts of IgG and IgA relative to IgM, the ratio of IgM to IgG in the second week being in all cases greater than 10. Similar patterns were seen in 25/29 cases of late onset hypogammaglobulinemia, and in the eight cases of X-linked hypogammaglobulinemia that responded in vitro. In contrast, the ratio of IgM to IgG was always less than 8 in cultures of normal adult peripheral blood or bone marrow lymphocytes, and also in cultures from four cases of hypogammaglobulinemia known independently to have abnormal circulating suppressor cells. Eight cases of selective IgA deficiency showed reduced IgA production; six of these showed a normal ratio of IgM to IgG production. Thus, the B lymphocytes which circulate in many patients with hypogammaglobulinemia are functionally immature.

Adult↗
PubMed1978

Removal by transamination and scission of residues from the peptide representing the copper-transport site of serum albumin.

The peptide Asp-Ala-His-NH-Me was subjected to removal of its N-terminal residue by transamination and scission. Despite the high affinity of the peptide for Cu2+ ions, they catalysed its transamination smoothly. Two main transamination products were found, a complication previously observed with another peptide with an N-terminal aspartic residue, but their scission gave a single product, Ala-His-NH-Me. This was subjected to a further cycle of transamination and scission, and gave a single product after each step. For scission of transaminated peptides it proved unnecessary to remove them from transamination reagents provided that transamination was stopped with EDTA before adding the scission reagent.

Biological Transport↗
PubMed1978

Absence of a newly described cytochrome b from neutrophils of patients with chronic granulomatous disease.

A unique cytochrome b which becomes incorporated into phagocytic vacuoles has been described in human neutrophils. This cytochrome b appears to be situated in the plasma membrane of these cells, and acts as a component of the microbicidal oxidase system. Absence or gross abnormality of this cytochrome b was demonstrated in all four patients with chronic granulomatous disease who were investigated, and reduced concentrations in two mothers known to be carriers of the disease.

Child↗
PubMed1978

X-linked ichthyosis due to steroid-sulphatase deficiency.

An assay of cultured skin fibroblasts identified several individuals with 3 beta-hydroxysteroid-sulphate sulphatase deficiency. All patients with this inborn error of metabolism had clinically apparent ichthyosis and a family history of this skin disorder compatible with X-linked inheritance. It is concluded that steroid-sulphatase deficiency is the bio-chemical basis of at least some cases of X-linked ichthyosis.

Adult↗
PubMed1978

An arsenical analogue of adenosine diphosphate.

An analogue of ADP was made in which the terminal phosphono-oxy group, -O-PO(OH)2, has been replaced by the arsonomethyl group, -CH2-AsO(OH)2. This compound cannot form a stable analogue of ATP because anhydrides of arsonic acids are rapidly hydrolysed, so that any enzyme that phosphorylates ADP and accepts this analogue as a substrate should release orthophosphate in its presence. The analogue proves to be a poor substrate for 3-phosphoglycerate kinase (V/Km is diminished by a factor of 10(2)-10(3)) and a very poor substrate for pyruvate kinase (V/Km is diminished by a factor of 10(5)-10(6)). No substrate action was detected with adenyl kinase and creatine kinase.

Adenosine Diphosphate↗
PubMed1977

The Lesch-Nyhan syndrome: a family study.

Two brothers were found to have athetoid cerebral palsy, mental and growth retardation and evidence of self mutilation. One had passed a renal calculus and both had high serum uric acid levels. The diagnosis of Lesch-Nyhan syndrome was confirmed by the finding of low levels of hypoxanthine-guanine phosphoribosyl transferase in erythrocytes and by autoradiography of fibriblasts. The mother, maternal grandmother, a female sibling and a maternal aunt were identified as carriers of the X-linked mutation which was responsible for the enzyme deficiency in the two male siblings.

Allopurinol↗