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Biomedical subjects

S Wells

Publications and source records attributed to S Wells.

At least 19 recordsLinked to original sources
PubMed1992

Humidification for ventilated patients.

When a patient is intubated with an endotracheal tube for artificial ventilation the humidifying, warming and filtering functions of the nose and upper airways are bypassed. This article reviews the need for the provision of artificial humidification, optimal levels that should be provided and the two types of device which are available to achieve this, namely, the heat and moisture exchanging devices and the heated vaporising or nebulising humidifiers. Finally a study is presented which documents the exact level of moisture delivered to patients by the cascade water bath humidifier.

Equipment Design↗
PubMed1992

Pseudoangiosarcomatous carcinoma: a clinicopathological study of seven cases.

Seven cases of carcinoma mimicking angiosarcoma occurring in skin (3 cases), breast (3) and lung (1) are described. The cutaneous, pulmonary and one of the breast carcinomas were poorly differentiated and squamous in type; the other two breast tumours were poorly differentiated ductal carcinomas with focal squamous differentiation. Histologically, the pseudoangiosarcomatous pattern was due to complex anastomosing channels and spaces lined by neoplastic cells. The spaces contained hyaluronic acid. The neoplastic cells exhibited cytokeratin positivity but yielded negative results with the endothelial cell markers, factor VIII-related antigen and CD 34 (QB-END/10). Two breast tumours showed binding of UEA-1. Ultrastructurally, unequivocal epithelial differentiation was demonstrated in six of the cases. Pathogenetically, these tumours appeared to be variants of acantholytic squamous cell carcinoma. Recognition of this unusual form of carcinoma is important, as an incorrect diagnosis of angiosarcoma may lead to inappropriate treatment and prognostication.

Aged↗
PubMed1991

A case of mosaicism involving an unstable 13/14 Robertsonian translocation.

Prenatal diagnosis of mosaicism involving an apparently unstable 13/14 Robertsonian translocation is reported. This illustrates the difficulties encountered in counselling when mosaicism is ascertained prenatally. Other reported examples of apparently unstable Robertsonian translocations are discussed.

Adult↗
PubMed1991

Molecular and cytogenetic analysis of a familial microdeletion of Xq.

Cytogenetic analysis of a male infant referred for poor neurological development and failure to thrive showed a microdeletion of the X chromosome, his karyotype being 46,Y,del(X)(pter----q21.1:: q21.2----qter). His mother and grandmother were also found to carry the deletion. DNA probes were used to define the deletion molecularly and it was shown to span intervals 2 to 6 of Cremers et al, a portion of Xq that contains the TCD gene and genes whose absence is associated with deafness and mental retardation. RFLP analysis together with X inactivation studies using the probe M27 beta verified the carrier status of the female relatives and showed non-random X inactivation in the heterozygous females.

Chromosome Banding↗
PubMed1991

Practice patterns of obstetricians and gynecologists in Jacksonville, Florida.

Ninety members of the Jacksonville Obstetrical and Gynecological Society were surveyed as to their practice patterns; 55 responded. Due to fear of litigation, 34% had stopped delivering obstetrical care and 63% plan to discontinue perinatal care during the next ten year. At least one malpractice claim had been filed against 51%; 9% had two, and 11% three or more. Prenatal and intrapartum testing has increased primarily because of fear of litigation. Obstetric fees increased 44% during the last five years, according to the survey, compared to a Consumer Price Index rise of 20%. Mean malpractice premiums rose 42% during the same interval.

Adult↗
PubMed1990

Eosinophilic meningoencephalitis due to Angiostrongylus cantonensis as the cause of death in captive non-human primates.

Fatal eosinophilic meningoencephalitis due to Angiostrongylus cantonensis is reported in captive non-human primates. A howler monkey (Alouatta caraya) at the Audubon Park and Zoological Gardens, New Orleans, LA, died 21 days after initial clinical symptoms. A white-handed gibbon (Hylobates lar) died at the Ardastra Gardens and Zoo, Nassau, Bahamas, 17 days after onset of symptoms. Both had access to free-ranging gastropods within the zoos. These are the first reported cases of natural infection by A. cantonensis in non-human primates in the western hemisphere.

Alouatta↗
PubMed1989

Language laterality in Navajo reservation children: dichotic test results depend on the language context of the testing.

Language lateralization in 40 Navajo and 20 Anglo fifth graders was assessed via the Dichotic Consonant-Vowel Task (DCVT). One group of Navajo children was tested by an experimenter who spoke only Navajo with them. The other Navajo group and the Anglo group were tested by an experimenter who spoke only English to them. Strong right ear advantages (REAs) were obtained for the Anglo group and for the Navajo group tested by the Navajo-speaking experimenter. The Navajo group tested by the English-speaking experimenter showed minimal, nonsignificant REAs. Previous findings of an absence of REAs in Native American children failed to consider the possibility that this might occur only when the experimenter does not speak the dominant language of the children. Our results are not consistent with the view that Native Americans are more right hemisphere dominant as a function of an "appositional" mode of language and thought.

Arizona↗
PubMed1989

Localization of the genetic defect in multiple endocrine neoplasia type 1 within a small region of chromosome 11.

Multiple endocrine neoplasia type I (MEN-1), a Mendelian disorder with an autosomal dominant mode of inheritance, causes hyperplasia in the parathyroid glands and hyperplasia or neoplasm in the anterior pituitary gland and/or the pancreatic islets. The genetic defect responsible for MEN-1 in three families was recently mapped to the long arm of chromosome II by linkage between the MEN-1 locus and the gene for skeletal muscle glycogen phosphorylase (PYGM) at 11q13. We have constructed a genetic linkage map of seven markers in the vicinity of the MEN-1 locus that has allowed us to map more precisely the gene associated with MEN-1; the target region has been narrowed to about 12 cM. The closely linked markers will be useful also for identification of likely carriers in families in which an allele responsible for MEN-1 segregates.

Chromosome Mapping↗
PubMed1988

Helically organized macroaggregates of pigment-protein complexes in chloroplasts: evidence from circular intensity differential scattering.

Angle dependence of circular intensity differential scattering (CIDS) and of nonpolarized scattering was determined in isolated spinach chloroplasts at 514.5 nm. CIDS between 0 degrees and 170 degrees was independent of the nonpolarized scattering and showed intense lobes of alternating signs, exhibiting the negative and positive maxima around 15 degrees and 70 degrees, respectively. These results provide experimental evidence for the existence of large helically organized macroaggregates of pigment-protein complexes in thylakoid membranes. Modeling of the CIDS data by a simple helical array of uniaxial polarizable groups suggests that the chiral structure is left-handed with pitch and radius of the order of 385 nm.

Chloroplasts↗
PubMed1988

Sequences contained within the promoter of the human thymidine kinase gene can direct cell-cycle regulation of heterologous fusion genes.

Recent evidence on the transcriptional regulation of the human thymidine kinase (TK) gene raises the possibility that cell-cycle regulatory sequences may be localized within its promoter. A hybrid gene that combines the TK 5' flanking sequence and the coding region of the bacterial neomycin-resistance gene (neo) has been constructed. Upon transfection into a hamster fibroblast cell line K12, the hybrid gene exhibits cell-cycle-dependent expression. Deletion analysis reveals that the region important for cell-cycle regulation is within -441 to -63 nucleotides from the transcriptional initiation site. This region (-441 to -63) also confers cell-cycle regulation to the herpes simplex virus thymidine kinase (HSVtk) promoter, which is not expressed in a cell-cycle manner. We conclude that the -441 to -63 sequence within the human TK promoter is important for cell-cycle-dependent expression.

Base Sequence↗
PubMed1988

Primary mucinous adenocarcinoma developing in an ileostomy stoma.

We report a mucinous adenocarcinoma arising in an ileostomy stoma of a 60 year old woman after a subtotal colectomy done 28 years previously for ulcerative colitis. A study of the histochemical profiles of the mucin within the mucosa of the ileostomy and the carcinoma was undertaken. Previously documented cases are reviewed.

Adenocarcinoma, Mucinous↗
PubMed1987

Pharmacokinetics of rimantadine hydrochloride in patients with chronic liver disease.

Six patients with chronic liver disease and six sex-, age (+/- 5 years)-, and weight (+/- 5 kg)-matched healthy control subjects received a single dose of two 100 mg tablets rimantadine HCl. Eight additional patients with chronic liver disease who were not matched to healthy subjects received a single dose of two 100 mg tablets of rimantadine HCl. Blood and urine samples were collected and rimantadine concentrations were determined by a GCMS method. The values for maximum plasma concentration, AUC, elimination half-life, and renal clearance were not significantly different between patients and control subjects, independent of the statistical analyses (parametric and nonparametric) used. The mean apparent elimination half-life, volume of distribution, and total clearance in the matched patients with liver disease were 32 hours, 24 L/kg, and 676 ml/min, respectively. Renal clearance and the amount excreted in the urine unchanged were 63 ml/min and 10%, respectively. In conclusion, rimantadine pharmacokinetics were not appreciably altered in patients with less severe chronic liver disease.

Adamantane↗
PubMed1987

Impaired muscarinic endothelium-dependent relaxation and cyclic guanosine 5'-monophosphate formation in atherosclerotic human coronary artery and rabbit aorta.

The dependence of vascular relaxation on an intact endothelium and the relationship between relaxation and cyclic GMP accumulation were determined in coronary arteries isolated from cardiac transplantation patients with or without coronary atherosclerosis. In nonatherosclerotic arteries, the endothelium-dependent agent acetylcholine produced concentration-related relaxations. In atherosclerotic arteries, endothelium-dependent relaxations were abolished with acetylcholine, partly suppressed with substance P and histamine, and completely preserved with the ionophore A23187. In these arteries, the endothelium-independent agent nitroglycerin remained fully active. Accumulation of cyclic GMP in atherosclerotic strips was suppressed with acetylcholine but unattenuated with A23187 and nitroglycerin. In aortas from rabbits with diet-induced atherosclerosis, there was likewise an impaired cholinergic relaxation and cyclic GMP accumulation in the presence of preserved responses to A23187 and nitroglycerin. The results demonstrate that impaired cholinergic responses in atherosclerotic arteries reflect a muscarinic defect and not an inability of endothelium to release endothelial factor or smooth muscle to respond to it.

Acetylcholine↗
PubMed1987

Do cardiorespiratory frequencies show entrainment with hopping in the tammar wallaby?

Breathing, heart and gait frequencies, tidal volume, cardiac output, and rates of oxygen consumption were measured in tammar wallabies (Macropus eugenii Desmarest) hopping on a treadmill. At speeds greater than 1.6 ms-1 the rate of metabolic power consumption was independent of hopping speeds. Blood lactate levels within the speed range where VO2 was independent of speed showed a mean increase of 4.8 mmol l-1. During bipedal hopping, the frequencies of breathing and limb movement are phase-locked in the ratio of 1:1. Inspiration begins as the animal leaves the ground and may be a passive process driven by a visceral piston. A relatively large central tendon in the diaphragm may correlate this function. Unlike breathing frequencies, cardiac frequencies show no entrainment with hopping. The site of dissipation of the presumed large arterial pressure excursion is unknown.

Animals↗
PubMed1986

Eating and weight problems among women attending their general practitioner.

One hundred and fifty-seven women between the ages of 16 and 40, attending their general practitioners, were given a self-report questionnaire containing standard instruments measuring weight concerns and eating attitudes and behaviours. The majority (72%) of women wanted to weigh less, 46% were dissatisfied with their body shape, 48% dieted at least sometimes with 24% usually or always dieting, and 21% wanted help with their eating or weight problems. Increasing disparity between actual weight and desired weight was associated with higher scores on the eating problem scales.

Adolescent↗
PubMed1986

The effect of divalent metal ions on the electrophoretic mobility of bovine prothrombin and bovine prothrombin fragment 1.

Examination of metal ion-dependent effects on the electrophoretic mobility of bovine prothrombin and fragment 1 provides a useful and sensitive method for investigation of conformational processes in these proteins. Utilization of this method reveals a conformational change in bovine prothrombin and fragment 1 which occurs at low metal ion concentrations. Equilibrium dialysis studies indicate that the metal ion-induced shape change occurs concomitant with binding of a single calcium ion/molecule of prothrombin or fragment 1. Mixed metal electrophoretic mobility studies with Mg2+ and Ca2+ have demonstrated the "synergistic" effect for fragment 1 observed by others. Mixed metal equilibrium dialysis has provided experimental support for this observation and allows us to conclude that two tight Ca2+ sites are not affected by low Mg2+ concentrations and that the third Ca2+ site is also a tight site for Mg2+. Thus, at low Mg2+ concentrations and upon the addition of Ca2+, there are effectively three tight sites; consequently more Ca2+ will bind to the protein at lower total Ca2+ ion concentrations.

Animals↗