Biomedical subjects

D Lewis

Publications and source records attributed to D Lewis.

At least 145 records · Page 8Linked to original sources

PubMed1995

Use of CHROMagar Candida medium for isolation of yeasts from dental samples.

A new differential medium, CHROMagar Candida, for the isolation of clinically important yeasts was investigated to determine its usefulness in facilitating the study of oral yeasts. The recovery of yeasts on the medium was not significantly different from the recovery on Sabouraud dextrose agar. The identities of 450 green colonies on CHROMagar Candida, presumptively identified as Candida albicans on the basis of the manufacturer's instructions, were confirmed by testing for beta-N-acetylgalactosaminidase. Candida tropicalis also formed distinctive colonies, and other yeasts including Candida (Torulopsis) glabrata, Candida Parapsilosis, Candida Magnoliae, Candida lusitaniae, Candida Famata, Candida kefir, and Saccharomyces cerevisiae were readily distinguished from C. albicans and C. tropicalis isolates. CHROMagar Candida is a very useful medium, and its use will facilitate the study of yeasts associated with dental diseases.

Candida↗

PubMed1995

Use of solid-phase immune electron microscopy for classification of Norwalk-like viruses into six antigenic groups from 10 outbreaks of gastroenteritis in the United States.

Norwalk-like viruses observed in fecal specimens from 10 outbreaks of gastroenteritis investigated in the United States between 1987 and 1992 were analyzed by solid-phase immune electron microscopy. Outbreak virus strains were classified into six antigenic groups: the four types (UK1 to UK4) previously defined in the United Kingdom, Norwalk virus, and the Oklahoma agent that was newly defined in this study. The diversity of antigenic types demonstrated in these outbreaks was greater than previously recognized and will serve as a basis for characterization of these strains at the molecular level.

Antibodies, Viral↗

PubMed1995

Measurement of serum troponin T, creatine kinase MB isoenzyme, and total creatine kinase following arduous physical training.

We have compared measurement of cardiac troponin T by enzyme linked immunosorbent assay with creatine kinase MB isoenzyme (CK-MB) concentration measurement in 219 Royal Marine commandos with no evidence of cardiovascular disease who have elevated creatine kinase (CK) produced by arduous physical training. CK was elevated up to 22.6 times and CK-MB mass up to 6.6 times the upper reference limit. Only two commandos had detectable cardiac troponin T, with neither exceeding the upper reference limit of 0.2 micrograms/L. At decision thresholds optimized for diagnosis of acute myocardial infarction in previous published work, 58.3% of the total CK activity, 13.8% of the CK-MB concentration/CK activity ratio and 1.6% of CK-MB concentration measurements showed elevated values but no elevations in cardiac troponin T occurred. Cardiac troponin T is currently the investigation of choice for the differential diagnosis of patients with an elevated CK due to skeletal muscle trauma to exclude myocardial damage.

Aspartate Aminotransferases↗

PubMed1995

Humoral response to Plasmodium falciparum ring-infected erythrocyte surface antigen in a highly endemic area of Papua New Guinea.

The prevalence and concentration of antibodies to ring-infected erythrocyte surface antigen (RESA) were measured in blood samples collected during a cross-sectional survey conducted in Papua New Guinea. Antibodies were measured by enzyme-linked immunosorbent assay to the recombinant RESA protein in 1,398 subjects and to RESA 8 and RESA 11 synthetic peptides in a subsample of 200 adults. Overall, the seropositivity rate to recombinant RESA was 66% and the geometric mean antibody concentration was 28 micrograms/ml. There was a slow increase in antibody prevalence and concentration with age that continued to occur even after 40 years of age. In children less than 10 years of age, there was a significant positive correlation between both RESA antibody prevalence and concentration and concurrent infection with Plasmodium falciparum. The opposite was true in adults more than 20 years of age, with those having a high antibody concentration to RESA being less likely to be parasitemic at the time of the survey. This observation was consistent with the finding of a weak but significant negative correlation between log antibody concentration and log P. falciparum density, which was mainly found in adults. No consistent correlation was found between humoral immune response to RESA and morbidity indicators.

Adolescent↗

PubMed1995

False-positive and false-negative rates in meconium drug testing.

To determine the number of false-negative results produced by inefficient extraction of drugs from meconium, three published procedures were compared by using previously confirmed positive and negative meconium specimens. The methods were not equivalent in their ability to extract drugs from the matrix. To determine the number of false positives reported by the use of screen-only (unconfirmed) results, 535 screen-positive meconium specimens were subjects to confirmation by gas chromatography-mass spectrometry. Fifty-seven percent of the samples were confirmed positive for one or more of the drugs under investigation, showing that a false-positive rate as high as 43% may exist when unconfirmed screening results are used.

Amphetamines↗

PubMed1995

Breast lymphoma. A clinical and pathological review and 10-year treatment results.

Sixteen patients presenting with lymphoma involving the breast are described. Seven fulfilled the criteria for primary breast lymphoma, while the other 9 had evidence (sometimes only detected after extensive staging procedures) of concurrent lymphomatous involvement outside the breast. Histological diagnoses of the so-called primary breast lymphomas included 1 case of Hodgkin's disease and 6 of non-Hodgkin's lymphoma (including 2 with T-cell phenotypes). The patients with so-called secondary breast involvement included 8 with non-Hodgkin's lymphoma and 1 with a plasmacytoma of the breast with concomitant myelomatous involvement of bone marrow. Among the non-Hodgkin's lymphomas involving the breast the whole range of histological subtypes from low-grade to high-grade lesions were seen. There was no subtype of lymphoma with a specific predilection for breast involvement. Expression of oestrogen receptor protein as determined by immunocytochemical investigation using specific monoclonal antibodies was uniformly negative in lymphoid cells of 11 patients studied. Most of the patients in this series were treated by chemotherapy with uniformly good local control of lymphomatous involvement of the breast and an outcome similar to that of lymphomas presenting at other body sites. It is concluded that the approach to lymphomas of the breast should be similar to that of the equivalent types presenting elsewhere.

Adult↗

PubMed1995

Multiple birth concordance of street drug assays of meconium analysis.

To determine the prevalence of maternal drug usage in a mid-size midwestern city (population 250,000), we analyzed 1,175 consecutive meconium samples from the neonatal intensive care unit from March 1991 through December 1993. We focused on meconium assays from multiple births as a quality control method. Meconium specimens were analyzed using fluorescence polarization immunoassay (FPIA-Abbott Diagnostics) with confirmation done by gas chromatography/mass spectrometry (GC/MS). Cutoff concentrations of 5 ng/g were utilized for all analytes. A total of 151 samples (12.9%) tested positive. Cocaine-exposed neonates had the highest positive rate (63 or 5.4%), followed by marijuana (52 cases or 4.4%), cocaethylene (12 cases or 1%), and amphetamine (1 case or 0.1%). Nine patients (0.8%) had multiple drugs present. There were a total of 23 sets of multiple births (21 twins, 2 triplets); 20 sets of multiple births (42 patients) had concordance with all births testing negative. Three sets of twins had concordance in testing positive, with 1 twin testing positive for cocaine while the other twin tested positive for cocaine and marijuana. No absolute discordance of twins assays were noted. The rate of maternal drug use through measurement of meconium is about 12.95% in this mid-sized midwestern city. Twin studies provide an excellent method for verifying fetal drug exposure. The use of sets of multiple births provides a unique internal quality control mechanism in determining fetal drug exposure.

Female↗

PubMed1995

Suspecting the obvious in rheumatology.

In rheumatological medicine taking an accurate history is essential. So too is the skill of observing a clinical sign, recognising its significance and then following through with an appropriate line of questioning. This article highlights some of the rheumatological signs that may be observed by a seemingly casual head to toe scan of a patient.

Humans↗

PubMed1995

Relative repellency of woodsmoke and topical applications of plant products against mosquitoes.

The repellent action of various plant products was evaluated against anopheline and culicine mosquitoes in a rural village in the Wosera area, Papua New Guinea. A 5 x 5 Latin square design was used. Wood from four home-grown plant species was burned outdoors in the first experiment, and mosquitoes attracted to human bait were collected from 1800 to 2400 hours. In the second experiment, bruised leaves from another four plant species were rubbed on to the legs of human baits followed by mosquito collections. Woodsmoke and topical applications reduced biting of human volunteers by 79% and 51%, respectively. This low-technology control method may be included in the range of options for householders in order to reduce mosquito nuisance and improve their standard of health.

Administration, Cutaneous↗

PubMed1994

Discontinuing antiepileptic drugs in children with epilepsy. A comparison of a six-week and a nine-month taper period.

BACKGROUND: The optimal regimen for discontinuing antiepileptic medications in children with epilepsy is unknown. METHODS: We randomly assigned 149 children to either a six-week or a nine-month period of drug tapering, after which therapy was discontinued. Each group was composed of patients who had been seizure-free for either two or four years before drug tapering was begun. Most patients were receiving one antiepileptic drug; none were taking more than two. The children were evaluated periodically during and after the taper period. Sixteen patients were lost to follow-up before the beginning of the taper period. Proportional-hazards regression analysis was used to assess the risk of seizure recurrence among the remaining 133 patients. RESULTS: Seizures recurred in 53 patients (40 percent). The mean duration of follow-up was 39 months (range, 11 to 105) for the patients who did not have a recurrence of seizures. Neither the length of the taper period (six weeks vs. nine months, P = 0.38) nor the length of time the patients were free of seizures before the taper period was begun (two years vs. four years, P = 0.20) significantly influenced the risk of seizure recurrence. The presence of mental retardation (relative risk, 3.1, 95 percent confidence interval, 1.5 to 6.2) or spikes in the electroencephalogram at the time of tapering (relative risk, 1.9, 95 percent confidence interval, 1.0 to 3.4) increased the risk of seizure recurrence. CONCLUSIONS: The risk of seizure recurrence during drug tapering and after the discontinuation of antiepileptic drug therapy in children with epilepsy is not different whether the medications are tapered over a six-week or a nine-month period.

Adolescent↗

PubMed1994

An evaluation of cervical screening in general practice.

OBJECTIVES: To identify the technical practices of general practitioners (GPs) in relation to Papanicolaou (Pap) smear screening, and the differences in screening practices between male and female practitioners; to determine the cellular content of smears taken; and to correlate screening practices and demographic variables with smear results. DESIGN: During February-May 1992, a sample of Melbourne GPs filled in a questionnaire concerning their screening practices, and the results were correlated retrospectively with results of Pap smears taken in March and October 1991. SETTING: Melbourne metropolitan general practice. PARTICIPANTS: One hundred and seventy-nine GPs (72% participation rate among eligible practitioners) from a sample obtained from the register of the Medical Board of Victoria. RESULTS: Female doctors took significantly more smears than male doctors. An opportunistic approach to cervical screening was most commonly practised, with the patient being asked to ring for her results and the practice staff only contacted her if the result was abnormal. Only 43% of doctors indicated the use of a specific reminder system when rescreening was due. Endocervical cells were present in 79% of smears. The presence of endocervical cells was found to be related to the year of a doctor's graduation (with both very recent and older graduates [pre-1960s] having lower endocervical cell rates), and to be positively correlated with more postgraduate training. CONCLUSIONS: Our study suggests that further education and training in cervical screening is needed for some GPs, in particular, male doctors, graduates of less than four or greater than 20 years, and those without postgraduate training.

Adult↗

PubMed1994

Comparison of UV absorption and electrospray mass spectrometry for the high-performance liquid chromatographic determination of domoic acid in shellfish and biological samples.

Domoic acid, a neurotoxic amino acid produced by the marine diatom Nitchia pungens multiseries, was determined in samples of anchovies, razor clams, mussels, crab, rat serum, urine and feces by HPLC with UV absorption and electrospray (ESI) mass spectrometric (MS) detection. Shellfish samples were extracted with methanol-water followed by clean-up of the extracts with solid-phase extraction cartridges (strong anion or strong cation exchange). An aliquot of the fraction containing the domoic acid was analysed by HPLC. HPLC column size, mobile phase composition and flow-rate were selected so that essentially the same conditions could be used for both HPLC-UV and HPLC-ESI-MS with selected ion monitoring (SIM) determinations. These included the use of acetonitrile-water-formic acid as the mobile phase, at a flow-rate of 0.2 ml/min (split 13:1 for HPLC-ESI-MS-SIM, 10 microliters/min to the mass spectrometer). The results indicated that extracts found positive by the HPLC-UV method could be readily confirmed directly by HPLC-ESI-MS-SIM without additional sample treatment down to levels of 0.1 micrograms/g of domoic acid. This study demonstrates the use of HPLC-ESI-MS-SIM for the routine confirmation of domoic acid in a wide variety of samples.

Animals↗

PubMed1994

A splice junction mutation in a new myopathic variant of phosphoglycerate kinase deficiency (PGK North Carolina).

We report on a 12-year-old boy with the myopathic form of phosphoglycerate kinase (PGK) deficiency, and unique kinetic and physical characteristics of the mutant enzyme (PGK North Carolina). A G-to-T substitution at the 5' end of intron 4 was identified in the PGK gene of this patient. The mutation destroys the consensus sequence GT at the 5' splice junction of the intron. Activation of a cryptic splice site within intron 4 causes the insertion into the transcript of a 30-bp fragment at the 5' end of intron 4. This insertion results in ten additional amino acids within the "nose" of the PGK molecule, but does not generate a frameshift or a premature stop codon.

Base Sequence↗

PubMed1994

Genomic diversity of small round structured viruses in the United Kingdom.

Fifty-two faecal specimens collected in the United Kingdom between 1986 and 1992, which contained small round structured virus (SRSV) particles, were tested by reverse transcriptase polymerase chain reaction assays using two primer pairs derived from sequences of Snow Mountain Agent and Norwalk virus. There was poor correlation between results obtained with each primer pair. Twenty specimens (38%) gave positive bands with SM51/31 primers and 18 (34%) were positive with SM52/32 primers, with a total of 30 specimens (57.7%) giving amplification products of the expected size with one or both primer pairs. Genomic variation was investigated by sequencing a 266 bp region of the RNA polymerase gene from nine strains which had been antigenically typed by solid phase immune electron microscopy (SPIEM). RNA sequence identities ranged from 53 to 99%. Three genomic groups were suggested by phylogenic analysis, the first of which contained Norwalk virus, Southampton virus, and strains typed by SPIEM as SRSV UK2. The second contained Snow Mountain agent and strains typed as either SRSV UK3 or UK4. The third contained strains typed as SRSV UK1 and strains untypeable by SPIEM. Some correlation was demonstrated when antigen typing by SPIEM and phylogenic grouping based on sequence data were compared.

Adult↗

PubMed1994

Malignant lymphoma with primary cardiac manifestations: a case report.

This case report describes a 29-year-old black patient presenting with right heart failure secondary to massive lymphomatous cardiac involvement. Additional sites of involvement included mesenteric lymph nodes and the small bowel. Malignant lymphoma with primary cardiac manifestations is very rare and follows an aggressive course. The importance of early diagnosis and commencement of immediate therapy is emphasized.

Adult↗

PubMed1994

Impact of nutritional rehabilitation on gastroesophageal reflux in neurologically impaired children.

The impact of nutritional rehabilitation on gastroesophageal reflux (GER) in 10 malnourished neurologically impaired children (NIC) was studied (mean age, 9.1 +/- 3.1 years). None of the children had an antireflux procedure (ARP), and all were fed exclusively through a percutaneous endoscopic gastrostomy (PEG). Malnutrition was defined as triceps skin fold thickness (TSF) below the fifth percentile for age and sex. GER was established using standard criteria for a 24-hour pH probe study. All children were treated with an H2 antagonist and a prokinetic agent, along with aggressive nutritional rehabilitation. When TSF was > or = 50th percentile, medications were stopped, and the 24-hour pH probe study was repeated. The mean weight gain was 8.8 +/- 3.7 kg over 8.4 +/- 2.3 months. The 24-hour pH probe study showed marked improvement after nutritional rehabilitation in six of 10 children. These children remained asymptomatic throughout long-term follow-up, without the use of medications. Two children had abnormal pH probe results and worsening clinical symptoms when taken off medications after nutritional rehabilitation. They were reexamined after reinstituting the prokinetic drug; results of the pH probe study were normal, and there was no clinical symptomatology. The patients were then given long-term medication. Two children (one with erosive esophagitis and one with persistent symptoms) underwent ARP. We conclude that despite accompanying GER, successful nutritional rehabilitation can be achieved in malnourished NIC, using PEG feeding and antireflux medication. Although some NIC with GER may need an ARP or long-term medication, in most malnourished NIC nutritional rehabilitation is associated with resolution of GER.

Adolescent↗

PubMed1994

Maternal cocaine use without evidence of fetal exposure.

We report a case of lack of fetal exposure to cocaine and benzoylecgonine as evidenced by meconium and hair analysis, but exposure to nicotine and its metabolite cotinine, after extensive maternal use of cocaine and nicotine. These data suggest that the mode of maternal use of cocaine and individual differences in placental handling of the drug may protect some fetuses, and highlight the need to address interpatient variability.

Adult↗

PubMed1994

Pharmacokinetics and tissue distribution of recombinant human transforming growth factor beta 1 after topical and intravenous administration in male rats.

Recombinant human transforming growth factor beta (rhTGF-beta 1) enhances the healing process after topical application to various animal wound models. A detailed pharmacokinetic and tissue distribution study was performed to support the clinical development of rhTGF-beta 1 for wound healing indications. Rats received radioiodinated or unlabeled rhTGF-beta 1 as an intravenous (iv) bolus or as a topical formulation applied to a full thickness wound. Plasma concentrations of TGF-beta 1 were estimated from TCA-precipitable radioactivity or were measured by ELISA. Following iv administration, the initial half-life was rapid (< 11 min), regardless of whether radiolabeled or unlabeled rhTGF-beta 1 was used. The terminal half-life was long (163 min) when the test material was radioiodinated and administered as a trace dose and relatively short (< or = 61 min) when given at high doses and assayed by ELISA. Analysis of plasma radioactivity by SDS-PAGE revealed a time-dependent clearance of the 25-kDa parent molecule without a significant appearance of lower molecular weight radiolabeled metabolites. The majority of the radioactivity was associated with highly perfused organs, known iodide elimination pathways, and the thyroid at 1 and 8 hr after iv injection. After topical administration of a high dose (0.8 mg/kg), no immunoreactive TGF-beta 1 was detectable in plasma samples taken over a 48-hr period. However, trace amounts (< or = 0.05 ng/mL) of acid-precipitable radioactivity were detected in plasma after topical application of [125I]rhTGF-beta 1 (1 microgram/kg, 126 microCi/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Topical↗