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T Boyd

Publications and source records attributed to T Boyd.

18 recordsLinked to original sources
PubMed2001

WT1 regulates the expression of the major glomerular podocyte membrane protein Podocalyxin.

The WT1 tumor suppressor gene encodes a zinc finger transcription factor expressed in differentiating glomerular podocytes. Complete inactivation of WT1 in the mouse leads to failure of mesenchymal induction and renal agenesis, an early developmental phenotype that prevents analysis of subsequent stages in glomerular differentiation [1]. In humans with Denys-Drash Syndrome, a heterozygous germline mutation in WT1 is associated with specific defects in glomeruli and an increased risk for developing Wilms Tumor [2,3]. WT1 target genes implicated in cell cycle regulation and cellular proliferation have been proposed [4], but the link between WT1 function and glomerular differentiation is unexplained. Here, we show that inducible expression of WT1 in rat embryonic kidney cell precursors leads to the induction of endogenous Podocalyxin, the major structural membrane protein of glomerular podocytes, which is implicated in the maintenance of filtration slits. Binding of WT1 to conserved elements within the Podocalyxin gene promoter results in potent transcriptional activation, and the specific expression pattern of Podocalyxin in the developing kidney mirrors that of WT1 itself. These observations support a role for WT1 in the specific activation of a glomerular differentiation program in renal precursors and provide a molecular basis for the glomerulonephropathy that is characteristic of Denys-Drash Syndrome.

3T3 Cells↗
PubMed2000

Recurrent umbilical cord torsion leading to fetal death in 3 subsequent pregnancies: a case report and review of the literature.

During a span of 3.5 years, a 30-year-old, gravida 9, para 3 woman experienced 3 pregnancies complicated by umbilical cord torsion and constriction. In each case, the complication resulted in acute vascular compromise and intrauterine fetal demise. Gross examination disclosed cord constriction and torsion at the fetal end of the cord in each instance. Histologic sections from the cord torsion sites demonstrated fibrosis and deficiencies in Wharton's jelly in each case. Cytogenetic studies prepared using fetal villous tissue demonstrated normal karyotypes in fetal cells from the first 2 pregnancies (46,XX and 46,XY, respectively). The karyotype from the third pregnancy showed a 46,XX,del(X)(q24) mutation in 3 of 15 cultured cells, while 12 of 15 cells possessed a normal 46,XX karyotype. This cytogenetic abnormality was not believed to represent the cause of fetal demise in this case. To our knowledge, this is the first report of umbilical cord torsion in 3 pregnancies within one family. The familial clustering observed in this report suggests that a genetic predisposition for umbilical cord torsion may exist in some cases.

Adult↗
PubMed1999

Measuring oral health: does your treatment really make a difference.

An understanding of a broader concept of health is increasingly important for all health professionals, including dentists, and has recently been incorporated as a key principle in the Government White Paper, The New NHS. This aims to deliver a dependable, high quality, egalitarian health service. In the past, performance measurements in the UK have often relied simply on those areas which are most easily quantified. For example, within the hospital service, performance was measured in terms of the cost and the number of finished consultant episodes, from which the 'purchaser efficiency index' was calculated. This tended to produce a driving force rewarding those doing more rather than those doing more better. It is analogous to the system which has been the backbone of NHS dental practice for many years, 'fee per item of service', where throughout is rewarded rather than outcome. However, the White Paper has signalled a move away from simply counting activity. From April 1999 within the hospital service the purchaser efficiency index has been replaced with more rounded measures, reflecting the changing concepts of health, in a new broader performance framework to determine what really counts for patients. It will focus on measuring health improvement, fairer access, better quality and outcome, including the views of patients.

Dental Care↗
PubMed1999

Reticulocyte hemoglobin content to diagnose iron deficiency in children.

CONTEXT: Early identification of iron deficiency in children is essential to prevent the damaging long-term consequences of this disease. However, it is not clear which indices should be included in a diagnostic panel for iron deficiency and iron deficiency anemia in children. OBJECTIVE: To develop an effective approach for the diagnosis of iron deficiency and iron deficiency anemia in young children. DESIGN AND SETTING: Retrospective laboratory analysis, carried out over 7 weeks in 1996, using blood samples ordered by pediatricians and sent to a large metropolitan hospital for analysis. PATIENTS: A total of 210 children (mean [SD] age, 2.9 [2.0] years; 120 were male) who had a lead screening test (complete blood cell count and plasma lead level) ordered by a primary care pediatrician. MAIN OUTCOME MEASURES: Levels of hemoglobin (Hb), iron, transferrin, transferrin saturation (Tfsat), ferritin, and circulating transferrin receptor and reticulocyte Hb content (CHr) among patients with and without iron deficiency, defined as Tfsat of less than 20%, and iron deficiency anemia, defined as Tfsat of less than 20% and Hb level of less than 110 g/L. RESULTS: Of the 210 subjects, 43 (20.5%) were iron deficient; 24 of these had iron deficiency anemia. Reticulocyte Hb content and Hb levels were the only significant predictors of iron deficiency (likelihood ratio test [LRT] = 15.96; P<.001 for CHr, and LRT = 6.59; P = .01 for Hb), and CHr was the only significant multivariate predictor of iron deficiency anemia (LRT = 30.43; P<.001). Plasma ferritin level had no predictive value (P = .97). Subjects with CHr of less than 26 pg (optimal cutoff value based on sensitivity/specificity analysis) had lower Hb level, mean corpuscular volume, mean corpuscular Hb level, serum iron level, and Tfsat, and increased red blood cell distribution width vs those with CHr of 26 pg or more (P<.001 for all). CONCLUSIONS: Reticulocyte Hb content level was the strongest predictor of iron deficiency and iron deficiency anemia in children. It holds promise as an alternative to biochemical iron studies in diagnosis.

Anemia, Iron-Deficiency↗
PubMed1996

An improved accuracy six-load component pedal dynamometer for cycling.

This paper describes a new six-load component pedal dynamometer designed for study of knee overuse injury in cycling. A unique capability of the dynamometer is the ability to interface with multiple pedal platforms of varying height while maintaining a desired elevation of the foot above the pedal spindle axis. The dynamometer was designed using a concept described in an earlier article by Quinn and Mote (1991, Exp. Mech. 30, 40-48) which measures shear strain across multiple, thin cross-sections. An optimal design technique was used for choosing dimensions of the load measuring cross-sections. A dynamometer was designed and built using the optimal results. Calibration, accuracy results, and sample data are presented. A comparison of accuracy reveals that the new dynamometer is more accurate than previously reported instruments.

Bicycling↗
PubMed1995

Fetoplacental histology as a predictor of karyotype: a controlled study of spontaneous first trimester abortions.

It has been suggested that inferences about fetal karyotype can be made from examination of placental and decidual histology in early, spontaneous abortions (SABs). We assessed the reproducibility and predictive value of histologic features in 75 karyotyped, first trimester SABs; 32% (24 of 75) had normal male karyotypes (46,XY) and 68% (51 of 75) were cytogenetically abnormal (29 trisomy, 12 triploidy, eight monosomy X, and two tetraploidy). Three pathologists independently assessed 17 fetal, placental, and decidual histological findings and made predictions about the karyotype (normal, abnormal, or uncertain). Good to excellent interobserver and intraobserver reproducibility (kappa > 0.58) was achieved for the identification of five histological features: villous cavitation, anucleate fetal erythrocytes, amnion, umbilical cord, and fetal tissue. When histology and karyotype were compared using Fisher's exact test, no histological feature was associated with "any abnormal karyotype," two features (anucleate, fetal erythrocytes and umbilical cord) were associated with a normal karyotype, two features (villous dysmorphism and cisterns) were associated with triploidy, and four features (villous hydrops, no umbilical cord, no fetal tissue, and no anucleate erythrocytes) were associated with trisomy. Despite these significant histological-cytogenetic associations, the positive predictive values of each of these histological features with their corresponding karyotypes were low, ranging from 0.41 to 0.73 (mean, 0.53). Our data suggest that certain histological features in first trimester SABs are associated with the SAB's karyotype and are reproducible; however, such histological features did not perform as well as diagnostic tests for predicting the likelihood of normal versus abnormal karyotype.

Abortion, Spontaneous↗
PubMed1993

Type X collagen degradation in long-term serum-free culture of the embryonic chick tibia following production of active collagenase and gelatinase.

Type X collagen has a very limited distribution during skeletal development in regions of hypertrophic cartilage destined for degradation. In solution assay, type X collagen is degraded to a 32-kDa cleavage product which is resistant to further degradation, suggesting this product may have a function in skeletal development. In this study, we have identified the 32-kDa cleavage product of type X collagen present in the conditioned media (CM) during incubation of isolated 12-day chick tibiae in the absence of serum. In this culture system, chondrocytes throughout the tibial cartilages hypertrophied and deposited type X collagen within their matrix. During culture, the cartilage matrix was degraded in two stages. First proteoglycan was lost followed by degradation of the collagenous components. Collagen degradation was accompanied by the release of active interstitial collagenase and gelatinase into the CM. Purified type X collagen incubated in this CM was cleaved to form a 32-kDa product which was resistant to further degradation. This cleavage product has the same electrophoretic mobility as the 32-kDa chain produced by purified human collagenase.

Animals↗
PubMed1987

Penetrating chest wounds: a 10-year review.

From January 1975 to December 1984, 93 patients with penetrating chest wounds were admitted to three hospitals in Regina. Sixty-three percent of the wounds were caused by knives and 34% by firearms. Sixty-three patients were treated conservatively, 18 patients had thoracotomy and 12 others underwent laparotomy. Of the 18 patients, 16 had wounds between the nipples; 8 of the 16 had injuries to the heart or great vessels. Whereas the majority of penetrating wounds to the chest may be treated by observation or thoracostomy alone, a surgical approach is recommended when penetrating injuries are thought to have traversed the mediastinum, because of the high incidence of associated cardiac injuries. In doubtful cases the decision should favour early thoracotomy.

Adolescent↗
PubMed1986

Adaptation of the quadrupole mass spectrometer to multipatient anaesthesia gas monitoring.

A series of modifications designed to increase the suitability of the quadrupole mass spectrometer for multipatient gas monitoring in the operating suite are presented and evaluated. The adaptations include a pressure-stabilised long capillary inlet system and computer control of the quadrupole filter together with tuning, calibration and subsequent multitheatre analysis and display of clinical information. A pilot study of three months clinical monitoring provided documentation of contributions towards the safety and effectiveness of anaesthesia. These included indication of equipment malfunction, and fluctuations in gas exchange associated with inappropriate ventilation, haemodynamic instability and variations in body temperature. Limited accuracy for carbon dioxide and a low signal-to-noise ratio together with rapid ageing of electron multipliers were identified as problems still only partially solved.

Anesthesia, Inhalation↗
PubMed1985

Family circles.

Explore the source record for details and available documents.

Adolescent↗
PubMed1982

Remote monitoring by mass spectrometry during anaesthesia. Evaluation of a suitable inlet system.

We describe a three-stage mass spectrometer inlet system suitable for use in operating theatres and evidence of its performance in delay and response times to step changes in oxygen and halothane concentrations. At 55 m and a sampled gas flow of 100mlmin-1, the inlet imposed a delay of 21s and prolonged the 10-90% response to 310ms for oxygen and 510ms for halothane. A linear relationship between inlet length and 10-90% response time at constant sampled gas flow was demonstrated for halothane but not for oxygen. Our results compared with those of other workers support the chosen compromise between practical flexibility and convenience versus maximum speed of response that was adopted in this system design.

Anesthesia, Inhalation↗
PubMed1981

An anaesthetic circuit to improve patient monitoring by gas analysis.

This circuit is designed to maximise the range of respiratory variables that can be monitored by a mass spectrometer either alone, or preferably in association with blood gas analysis. In particular, it permits monitoring of respiratory dead space, lung shunt, ventilation, and gas exchange, as well as inspired and end-expired gas concentrations. Laboratory and clinical data indicate satisfactory performance of the circuit both clinically and analytically. The circuit is most suitable for controlled ventilation where, by operating as a "minute volume divider", it confers stability of minute volume on the manual ventilation technique.

Adult↗
PubMedDate not supplied

Prenatal alcohol exposure and cognitive development in the preschool years.

The teratogenic effects of drinking during pregnancy on cognitive development were investigated in a cohort of disadvantaged mother-infant pairs. Three indices associated with maternal alcohol use were related to comprehensive cognitive measures obtained during five in-home assessments through age four years, ten months. Birth weight and a tally of craniofacial anomalies were also evaluated as early indicators of fetal alcohol damage. Multiple analyses relating the alcohol and cognitive measures provided no evidence of an adverse alcohol effect on cognitive development in the absence of Fetal Alcohol Syndrome. Assessments based on confidence intervals indicated that an average decrement of more than two points (IQ equivalent) on the five cognitive measures is unlikely for relatively heavy levels of maternal alcohol use or alcohol-related problems. Marginal relationships were observed between cognitive measures and the neonatal indicators, but depended heavily on the influence of a child exhibiting signs consistent with Fetal Alcohol Syndrome. This case therefore received special attention. The implications of the relationships involving the neonatal indicators were investigated using arguments based on path analysis.

Alcohol Drinking↗
PubMedDate not supplied

Nondysplastic fetal renal hypoplasia associated with severe oligohydramnios: clinical, pathologic, and morphometric findings.

Two fetuses with severe bilateral renal hypoplasia are described; both diagnoses were made following elective abortion for oligohydramnios and suspected renal dysplasia. A 20-week female fetus (46,XX) had pulmonary hypoplasia and very small kidneys (7% of expected weight) that were normally shaped and nondysplastic, with well-formed medullae and metanephric blastema and markedly diminished cortices with only rare glomeruli. A 23-week male fetus (46,XY) had small kidneys (13% of expected weight) that were nondysplastic, normally shaped, and histologically well organized with moderately decreased numbers of glomeruli. Isolated bilateral renal hypoplasia has not previously been well characterized in fetuses; the presence of oligohydramnios (both cases) and pulmonary hypoplasia (one case) suggests that this finding is associated with impaired fetal renal function and may adversely influence neonatal survival.

Female↗