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Biomedical subjects

T McDonald

Publications and source records attributed to T McDonald.

At least 55 records · Page 3Linked to original sources
PubMed1997

A computerised implementation of a minimum set of health indicators.

Three alternative approaches to computerise primary health care services as provided in clinics in South Africa are compared. The first approach implements a system based on a head-count approach using a minimum set of indicators. This system resembles the current manual system of tally sheets. The second and third approaches implement computer systems based on patient records. The second approach is based on a very limited data set, and the third utilizes a comprehensive demographic and clinical data set. The three alternatives are compared with regard to practicality, flexibility, ease of use, accuracy and completeness of statistical reports, and time utilisation. It is concluded that the flexibility of a patient-record approach, although more time consuming, is preferred. The second alternative is more feasible in a developing country with mostly computer-illiterate nurses. Ways in which such a system can be implemented in an environment with limited hardware resources are also proposed.

Ambulatory Care Information Systems↗
PubMed1996

Regional localization of over 300 loci on human chromosome 22 using a somatic cell hybrid mapping panel.

A somatic cell hybrid panel, consisting of 25 cell lines, has been developed to localize loci subregionally on chromosome 22. Over 300 markers in the form of STSs or hybridization probes have been assigned to one of 24 unique regions or "bins" using this panel. This ordered collection of markers will aid in the assembly of physical maps and contigs of chromosome 22 and assist in positional cloning of disease loci mapped to chromosome 22.

Animals↗
PubMed1996

Regulation and characterization of the interferon-alpha present in patients with advanced human immunodeficiency virus type 1 disease.

To examine a possible association between plasma viremia and interferon-alpha (IFN-alpha) in patients with the acquired immunodeficiency syndrome (AIDS), we performed IFN plasma immunoadsorption by apheresis (IFN-alpha apheresis) in four volunteers with AIDS who had sustained levels of endogenous plasma IFN-alpha. IFN-alpha apheresis with two plasma volume exchanges was performed daily for 5 days. Clinical signs and symptoms and hematologic, virologic, and immunologic parameters were monitored. Two subjects developed anemia from phlebotomy, and one had a catheter++-associated bacteremia. The IFN-alpha apheresis was effective only in transiently removing IFN-alpha: depletion of IFN-alpha led only to its rapid reconstitution. Cell-associated HIV-1 was unchanged, but three of four subjects had a modest decrease in culturable plasma virus burden following the procedures. The recovery of in vivo HIV-1-related IFN-alpha by apheresis allowed its biologic and biochemical characterization. The HIV-1 IFN-alpha showed characteristics on ELISA, western blot, and biologic assays similar to two subspecies of the natural protein. The natural, recombinant, and HIV-1-induced IFN-alpha s demonstrated nearly identical antiviral activities. The HIV-1 IFN-alpha eluted from the column was not acid labile. The inability of large amounts of plasma IFN-alpha found in some patients with AIDS to affect viral burden likely reflects properties of the virus or of host factors independent of IFN-alpha.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Early citizen review: does it make a difference?

Case review, designed to promote adequate and appropriate planning and service delivery for children in foster care, is expected to reduce time in foster care and to lead to permanent placement outcomes. This article reports the results of a study on the impact of external citizen review initiated 14 to 45 days after a child entered the court system. Comparisons were made between two study groups to determine the impact of early citizen review on services planned and provided, court delays, completeness of the written case plans, number of placements, time in placement, and achievement of permanent placement. Implications for policy and practice are discussed.

Case Management↗
PubMed1996

Changes in cerebral blood flow velocity in children during sevoflurane and halothane anesthesia.

The purpose of this study was to evaluate arterial blood pressure and middle cerebral artery blood flow velocity in children during induction of anesthesia with sevoflurane. These measures were compared to findings in a control group anesthetized with halothane. Each child received mask induction of sevoflurane (n = 9) or halothane (n = 9) with 70% nitrous oxide in oxygen. Blood pressure was measured noninvasively by an oscillometric technique using a Dinamap. Blood flow velocity was measured using a transcranial Doppler with a 2-MHz probe. End-tidal CO2, nitrous oxide, and anesthetic concentrations were measured by a Datex Ultima Capnomac. Both sevoflurane (2.4%) and halothane (1.3%) combined with 70% nitrous oxide decreased blood pressure and increased cerebral blood flow velocity. Intubation increased blood pressure and further increased cerebral blood flow velocity with both anesthetic treatments. These results indicate that sevoflurane and halothane combined with nitrous oxide decrease blood pressure and increase cerebral blood flow velocity and suggest that sevoflurane produces cerebrovascular effects similar to those of halothane during anesthetic induction.

Anesthesia, Inhalation↗
PubMed1996

A new deletion of 18q23 with few typical features of the 18q- syndrome.

We report on a patient with a deletion of 18q23. At both 2 and 4 years of age, she displayed few of the facial features or other clinical features associated with the 18q- syndrome. Fluorescent in situ hybridisation and microsatellite marker and RFLP analysis were performed to characterise the extent of the deletion, and a terminal deletion of 18q23 was confirmed. The deleted region includes the gene for myelin basic protein, suggesting that hemizygosity of this gene does not invariably lead to mental and developmental delay. The clinical presentation of this patient suggests that either she is not deleted for the genes involved in the 18q- clinical phenotype or this patient represents one end of the spectrum of the clinical variability seen with 18q terminal deletions.

Abnormalities, Multiple↗
PubMed1995

Harlequin ichthyosis--a case report.

The Harlequin infant represents the most severe form of nonbullous ichthyosis. Although the clinical features of infants with Harlequin ichthyosis are generally similar, histological, ultrastructural, and biochemical analyses have not shown consistent findings. An unexpected case of Harlequin ichthyosis in a female infant born at 35 wks gestation is presented. Light microscopic and ultrastructural investigations of skin biopsies are detailed. The presence of extracellular lipid material in the stratum corneum has not been described in the previously reported cases of Harlequin ichthyosis.

Fatal Outcome↗
PubMed1995

Where are the costs in perioperative care? Analysis of hospital costs and charges for inpatient surgical care.

BACKGROUND: Many health-care institutions are emphasizing cost reduction programs as a primary tool for managing profitability. The goal of this study was to elucidate the proportion of anesthesia costs relative to perioperative costs as determined by charges and actual costs. METHODS: Costs and charges for 715 inpatients undergoing either discectomy (n = 234), prostatectomy (n = 152), appendectomy (n = 122) or laparoscopic cholecystectomy (n = 207) were retrospectively analyzed at Stanford University Medical Center from September 1993 to September 1994. Total hospital costs were separated into 11 hospital departments. Cost-to-charge ratios were calculated for each surgical procedure and hospital department. Hospitalization costs were also divided into variable and fixed costs (costs that do and do not change with patient volume). Costs were further partitioned into direct and indirect costs (costs that can and cannot be linked directly to a patient). RESULTS: Forty-nine (49%) percent of total hospital costs were variable costs. Fifty-seven (57%) percent were direct costs. The largest hospital cost category was the operating room (33%) followed by the patient ward (31%). Intraoperative anesthesia costs were 5.6% of the total hospital cost. The overall cost-to-charge ratio (0.42) was constant between operations. Cost-to-charge ratios varied threefold among hospital departments. Patient charges overestimated resource consumption in some hospital departments (anesthesia) and underestimated resource consumption in others (ward). CONCLUSIONS: Anesthesia comprises 5.6% of perioperative costs. The influence of anesthesia practice patterns on "downstream" events that influence costs of hospitalization requires further study.

Anesthesia↗
PubMed1995

Outcomes assessment: at what cost?

Outcomes assessment has become a major focus for evaluating managed care, but little is known about the feasibility and costs of a comprehensive outcomes assessment program. In this pilot study, more than 200 patients who were scheduled for elective hospital admissions were assessed using the Short Form 36. This instrument was mailed to patients the week before admission and three months after discharge. Cost for each complete set of pre- and post surveys was more than $60. Data from the SF-36 suggests that diagnosis-specific instruments and survey timing are necessary, which would increase the cost of outcomes assessment.

California↗
PubMed1995

A randomized evaluation of a computer-based physician's workstation: design considerations and baseline results.

We are performing a randomized, controlled trial of a Physician's Workstation (PWS), an ambulatory care information system, developed for use in the General Medical Clinic (GMC) of the Palo Alto VA. Goals for the project include selecting appropriate outcome variables and developing a statistically powerful experimental design with a limited number of subjects. As PWS provides real-time drug-ordering advice, we retrospectively examined drug costs and drug-drug interactions in order to select outcome variables sensitive to our short-term intervention as well as to estimate the statistical efficiency of alternative design possibilities. Drug cost data revealed the mean daily cost per physician per patient was 99.3 cents +/- 13.4 cents, with a range from 0.77 cent to 1.37 cents. The rate of major interactions per prescription for each physician was 2.9% +/- 1%, with a range from 1.5% to 4.8%. Based on these baseline analyses, we selected a two-period parallel design for the evaluation, which maximized statistical power while minimizing sources of bias.

Ambulatory Care Information Systems↗
PubMed1994

Relationships of Na+ and K+ concentrations to GRP, CGRP, and calcitonin immunoreactivities and Na+,K(+)-ATPase (NKA) inhibitory activity in human breast cyst fluid.

BACKGROUND: Although the etiology of gross cystic disease of the breast is unknown, elevated cyst concentrations of potassium (K+) (> 60 mM/L) may be related to symptoms. The purpose of this study was to clarify the mechanism(s) of K+ accumulation in breast cysts. METHODS: We assayed cyst fluids for factors known to exert effects on K+ transport, namely, endogenous digitalis-like inhibitors of Na+,K(+)-ATPase (NKA) and the neuropeptides gastrin-releasing peptide (GRP), calcitonin (CT), and calcitonin gene-related peptide (CGRP). RESULTS: Cyst fluid K+ was directly correlated with cyst volume, cyst NKA inhibitory activity (in ouabain equivalents), and cyst concentrations of calcitonin, GRP, and CGRP. Cyst fluid Na+ was inversely correlated with cyst fluid K+, cyst NKA inhibitory activity, cyst volume, and cyst fluid concentrations of calcitonin, GRP, and CGRP. NKA inhibitory activity correlated directly with GRP and CGRP. Immunocytochemistry localized GRP to breast cyst lining cells and areas of ductal and lobular epithelial hyperplasia in biopsies of 15 of 15 cysts and in 5 of 5 breast carcinomas, but not in (0 of 5) normal breast biopsies. Specificity of GRP staining was demonstrated by total abolition of reactivity after adsorption with synthetic GRP, but not after adsorption with synthetic substance P, neurokinin A, or neurokinin B. CONCLUSIONS: We conclude that both the concentrations of endogenous digitalis-like factors and the neuropeptides calcitonin, GRP, and CGRP in human breast cyst fluids are related to the concentrations of K+ and Na+ in breast cysts and to cyst volume.

Adult↗
PubMed1993

Experience with one-stage laryngotracheal reconstruction.

Eight patients (ages 10 months to 5 years) underwent laryngotracheal reconstruction (LTR) without intraluminal stenting or tracheostomy. All patients had moderate to severe acquired or congenital subglottic stenosis. Six patients were tracheostomy-dependent prior to reconstruction. The other two children were intubated and would have required tracheostomy for airway control. LTR and decannulation/extubation were accomplished as a one-stage procedure. Autologous rib cartilage was used (anterior graft only--6 patients, anterior and posterior graft--3 patients) and patients were intubated for 7-10 days. Pulmonary complications from the week-long intubation and intensive care unit stay were common, but easily managed. Seven of eight patients were successfully decannulated/extubated.

Cartilage↗
PubMed1993

Postmarketing surveillance of quinolones, 1990 to 1992.

During the last 2 years, the major event in the postmarketing surveillance of quinolones has been the worldwide withdrawal of temafloxacin after only 15 weeks on the USA market. The Adverse Drug Reaction (ADR) reports that led to the withdrawal have been reviewed and show that the frequency and type of ADR and serious ADR were highly unusual in comparison with other quinolones marketed in the USA (ciprofloxacin, norfloxacin and ofloxacin). The difficulty in establishing causality between drugs and ADRs is discussed. Prescription event monitoring and computerised databases are beginning to reach the size required to pick up rare ADRs but, even so, they can only establish association rather than causality. Perhaps a more important question is the issue of acceptable risk. This requires better definition in order to apply decision analysis to the options available for the treatment of bacterial infections.

Adverse Drug Reaction Reporting Systems↗
PubMed1992

Abnormal chloride conductance in multidrug resistant HL60/AR cells.

Chloride channel currents were measured in drug sensitive parental HL60 and multidrug resistant (MDR) subline HL60/AR cells, using a whole cell patch-clamp technique. In addition, the in vitro effects of 4,4' diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), a Cl- channel blocker, on intracellular accumulation and sensitivity to daunorubicin and intracellular pH (pH(i)) in HL60 cells were examined. Baseline DIDS blockable Cl- currents were consistently lower in HL60/AR cells (0.9 pA/pF) as compared to HL60 cells (7.0 pA/pF). Similarly cAMP-activated Cl- currents were minimal in HL60/AR cells (0.2 pA/pF) as compared to HL60 cells (8 pA/pF). In vitro treatment of drug sensitive HL60 cells with DIDS resulted in concentration-dependent decreased accumulation and increased resistance to daunorubicin and decreased pH(i). These data show that altered Cl- permeability is associated with MDR and suggest that Cl- channels may play a role in MDR.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1992

Natural killer cell activity in very low birth weight infants.

The exact role of natural killer (NK) cells in host defense is unclear, but they may be important as an early response to certain infections. We evaluated NK cell phenotype and activity in premature very low birth weight infants (VLBWI) (n = 52) with an average gestational age of 29.3 wk (24-35 wk) and an average birth weight of 1124 g (537-1480 g). All patients initially were evaluated within 7 d of birth. Samples also were obtained at 2, 4, and 6 wk in some infants. The proportion of mononuclear cells expressing the phenotypic marker of NK cells (NKH-1; CD56) was significantly lower in VLBWI than in adults (2.5 +/- 1.4 versus, 12.5 +/- 7.8%, p less than 0.0001) or term infants (2.5 +/- 1.4 versus 9.5 +/- 7.1%, p less than 0.0001). VLBWI also had significantly diminished NK activity expressed as the percentage of specific lysis compared with adults (4.7 +/- 4.4 versus 32.3 +/- 14.5%, p less than 0.0001) or term infants (4.7 +/- 4.4 versus 15.5 +/- 10.8%, p less than 0.0001). Both the number of cells expressing the NK phenotype and the NK lytic activity in VLBWI increased in the 6 wk after birth. NK activity in VLBWI was enhanced by IL-2 and in most cases by interferon-gamma.

Adult↗
PubMed1991

Post-marketing surveillance of quinolones 1988-1990.

It has been much easier to obtain original data on adverse drug reactions (ADR) of quinolones from the pharmaceutical industry than it was two years ago. This is to be welcomed and, as anticipated, the new data continue to suggest that the new 4-quinolones have an ADR profile which is very similar to that of other antimicrobials. Visual disturbance is not a prominent feature, in contrast to the ADR profile of nalidixic acid. Better definition of quinolone ADRs requires prospective study, and the results of a newly completed prescription event monitoring study are awaited with interest. The potential use of computerised databases and record linkage is examined, but at present the number of quinolone prescriptions is too small to assess documentation of serious but rare events such as convulsions. Physicians need to be aware of the limitations of current data on suspected ADRs. Further investment in computerised databases is required to satisfy the requirements for attributing causality of an event to a drug.

4-Quinolones↗
PubMed1991

Activation of cFos in ovine fetal corticotropin-releasing hormone neurons at the time of parturition.

The ovine fetal pituitary adrenal axis plays an important role in parturition. While lesions of the paraventricular nucleus (PVN) in the fetal sheep delay parturition, suggesting that the PVN is necessary for the processes that lead up to parturition, evidence for stimulation of PVN neurons at time of delivery/labor is lacking. The present study tested the hypothesis that activation (evidenced by expression of the oncogene product cFos) of a specific population of PVN neurons containing CRH accompanies labor in sheep. Monitoring of uterine electromyogram activity determined the onset of labor. The brains of nine fetuses (removed by ceasarian section under anesthesia at gestational ages of 125-145 days) and four newborn sheep were perfused and stained for cFos and CRH. Before labor, less than 5% of fetal paraventricular CRH neurons expressed cFos. Verification that the CRH neurons could express cFos when adequately stimulated was made by exposing an additional group of four preterm animals (125 days gestational age) to hypoxemia; the six untreated fetuses served as controls. Activation of the CRH neurons by hypoxemia produced a rapid induction of cFos in CRH neurons, with approximately 50% of the cells strongly expressing cFos protein 1 h after exposure to hypoxia. At the time uterine contractions were first detected, 70% of CRH neurons expressed cFos, and cFos immunoreactivity persisted until just after birth. cFos staining declined rapidly, reaching prelabor levels in some animals by 2-3 h after birth. These data are consistent with the hypothesis that in addition to their potential role in the processes that initiate parturition over several days before birth, fetal CRH neurons are stimulated during labor, and termination of stimulation probably occurs rapidly after delivery.

Animals↗