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Biomedical subjects

A Watson

Publications and source records attributed to A Watson.

At least 181 records · Page 10Linked to original sources
PubMed1994

Infant growth charts.

Detection and monitoring childhood growth disorders requires the correct use of growth charts. A check on the accuracy of every point plotted on Gairdner-Pearson growth charts of premature infants in a hospital paediatric department was carried out. Errors beyond set limits were recorded. Of 611 points plotted on the growth charts of 50 premature infants who were at least 1 year of age at the time of the study, there were 173 (28.5%) points plotted in error. Altogether 94.7% of the errors occurred when plotting the age along the horizontal (X) axis of the growth chart, irrespective of whether weight, length, or head circumference was being measured. There was no evidence that the errors caused appreciable changes in clinical management. Potential sources of error identified were failure to adjust for prematurity correctly, inaccuracy in calculating age, and the use of the logarithmic scale. These errors could be serious and it is important that there should be greater vigilance in using growth charts. The use of age calculators or improved chart design is recommended. Assessment of the use of other growth charts in different settings is also suggested.

Anthropometry↗
PubMed1994

Effect of magnetic susceptibility contrast medium on myocardial signal intensity with fast gradient-recalled echo and spin-echo MR imaging: initial experience in humans.

PURPOSE: To show the effect of dysprosium diethylenetriaminepentaacetic acid bis-methylamine injection on the images of normal human myocardium. MATERIALS AND METHODS: T2-sensitive fast gradient-recalled echo (GRE) (repetition time [TR], 10.8 msec; echo time [TE], 4.2 msec) and spin-echo (SE) (TR, three RR intervals; TE, 60 msec) magnetic resonance (MR) imaging with driven equilibrium-preparation pulse was used to produce T2 contrast material enhancement. The contrast agent was injected into 12 healthy subjects at doses of 0.05, 0.1, 0.2, 0.4, and 0.6 mmol/kg. RESULTS: Driven equilibrium-prepared GRE images showed a transient decrease of myocardial signal intensity at doses of 0.2-0.6 mmol/kg. Postcontrast T2-weighted SE images showed a myocardial signal attenuation (30%-45% decrease) at a dose of 0.4 mmol/kg or higher. CONCLUSION: Dynamic MR imaging with a magnetic susceptibility contrast medium can be used to monitor the first pass of contrast media through human myocardium with a conventional MR imager and a fast GRE sequence.

Adult↗
PubMed1994

A workplace intervention for increasing outdoor workers' use of solar protection.

OBJECTIVES: Outdoor workers are at high risk of developing skin cancer. Primary prevention in this group can potentially reduce the incidence of skin cancer, and also potentiates the spontaneous remission of existing solar keratoses. A randomized controlled trial was conducted to evaluate a solar protection intervention targeting outdoor workers. METHODS: Outdoor workers were randomly allocated to an intervention (n = 65) or control group (n = 77). The intervention group received individual skin screening by a dermatologist and participated in an education session. Pre- and posttest outcome measures included solar protection behavior (assessed using a validated diary), knowledge, and attitudes. RESULTS: There was a significant increase (16%) in the percentage of outdoor workers who were using a high level of solar protection at posttest compared to pretest in the intervention group, but there was no change in the control group. Although both groups improved in their knowledge score, the intervention group showed a significantly greater improvement at posttest. No changes in attitudes were detected. CONCLUSIONS: The findings suggest that changes in solar protection are achievable with outdoor workers.

Adult↗
PubMed1994

Influence of thoracic epidural analgesia on outcome after resection for esophageal cancer.

BACKGROUND: Many series have reported a lessening of the incidence of anastomotic dehiscence after thoracoabdominal resection of esophageal carcinomata. This has resulted in fatal respiratory complications assuming a relatively greater role as a cause of death after such procedures. This study was conducted to investigate the impact of the routine use of thoracic epidural analgesia on respiratory complications after resection for esophageal carcinoma. METHODS: The incidence of respiratory complications and the effect on outcome were studied in two groups of patients undergoing thoracoabdominal esophagogastrectomy for esophageal cancer during a 15-year period. The first group comprised 81 patients who underwent operation from 1975 through 1985 in whom thoracic epidural analgesia was not used; the second group comprised 75 patients who underwent operation from 1985 through 1990 in whom thoracic epidural analgesia was used routinely. RESULTS: In the latter group, the incidence of respiratory complications was 13%, and no fatal respiratory complications occurred, compared with corresponding figures of 30% and 5% in the nonepidural group. The 30-day/hospital mortality during the first period was 9.8% and 6.6% in the 75 patients in whom thoracic epidural analgesia was used routinely. CONCLUSIONS: The results of this study suggest that the routine use of thoracic epidural analgesia during thoracoabdominal esophagogastrectomy for esophageal cancer reduces the incidence of fatal and nonfatal respiratory complications and should be incorporated into routine surgical management of operable esophageal cancer.

Adenocarcinoma↗
PubMed1993

Cloning and characterisation of telomeric DNA from Cladosporium fulvum.

The molecular cloning of DNA from the telomere of one chromosome of Cladosporium fulvum, a fungal pathogen of tomato, is described. The telomeric DNA exhibits tandem repeats of the sequence TTAGGG running 5' to 3' toward the chromosome end. At least 16 tracts of TTAGGG repeats are present in the C. fulvum genome. All such tracts are telomeric, and all chromosome-sized DNAs separated by pulsed-field gel electrophoresis exhibit the repeats. It is probable that tracts of these repeats are present at all chromosome termini. The cloned telomeric DNA exhibits 19 copies of the TTAGGG hexanucleotide motif, and evidence is presented indicating that all tracts of TTAGGG repeats are quite short. Telomere-linked restriction-fragment length polymorphisms between races of C. fulvum have been detected, and groupings based on these polymorphisms are consistent with those determined previously. Sub-telomeric DNA, centromere proximal to the cloned telomeric DNA, contains sequences reiterated many times in the genome; some of these repeats are at non-terminal locations. Partial sequence analysis indicates an absence of homology with the sub-telomeric DNA of other organisms.

Base Sequence↗
PubMed1993

Case-control study of leukaemia and non-Hodgkin's lymphoma among children aged 0-4 years living in west Berkshire and north Hampshire health districts.

OBJECTIVE: To investigate the relation between parental employment in the nuclear industry and childhood leukaemia and non-Hodgkin's lymphoma. DESIGN: Case-control study. SETTING-West Berkshire and Basingstoke and North Hampshire District Health Authorities. SUBJECTS: 54 children aged 0-4 years who had leukaemia or non-Hodgkin's lymphoma diagnosed during 1972-89, who were born in the study area and were resident there when cancer was diagnosed. Six controls were selected for each case: four from hospital delivery registers and two from livebirth registers maintained by the NHS central register. Controls were matched for sex, date of birth (within six months), and area of residence at birth and time of diagnosis. MAIN OUTCOME MEASURES: Parents' employment by the nuclear industry and exposure to ionising radiation at work. RESULTS: Five (9%) of the 54 cases and 14 (4%) of the 324 controls had fathers or mothers, or both, who had been employed by the nuclear industry (relative risk 2.2, 95% confidence interval 0.6 to 6.9). Nuclear industry employees who work in areas where exposure to radiation is possible are given film badges to monitor their exposure to external penetrating ionising radiation. Three fathers of cases and two fathers of controls (and no mothers of either) had been monitored in this way before their child was conceived (relative risk 9.0, 95% confidence interval 1.0 to 107.8). No father (of a case or control) had accumulated a recorded dose of more than 5 mSv before his child was conceived, and no father had been monitored at any time in the four years before his child was conceived. A dose-response relation was not evident among fathers who had been monitored. CONCLUSIONS: These results suggest that the children of fathers who had been monitored for exposure to external penetrating ionising radiation in the nuclear industry may be at increased risk of developing leukaemia before their fifth birthday. The finding is based on small numbers and could be due to chance. If the relationship is real the mechanisms are far from clear, except that the effect is unlikely to be due to external radiation; the possibility that it could be due to internal contamination by radioactive substances or some other exposure at work should be pursued. The above average rates of leukaemia in the study area cannot be accounted for by these findings.

Case-Control Studies↗
PubMed1993

Iron management during treatment with recombinant human erythropoietin in chronic renal failure.

The anemia of chronic renal failure often contributes to the poor functional status in patients with renal insufficiency and results primarily from decreased erythropoietin production. Recombinant human erythropoietin (rHuEpo) results in clinical and symptomatic improvements in patients with anemia of chronic renal failure. Treatment with rHuEpo also improves the quality of life in these patients. Resistance to rHuEpo therapy is not uncommon, however, and often is related to iron deficiency resulting from rapid erythropoiesis during rHuEpo therapy. Interestingly, rHuEpo-treated patients may continue to develop iron deficiency while receiving oral iron. Alternatively, parenteral iron is effective in replenishing iron stores and sustaining erythropoiesis in patients treated with rHuEpo.

Erythropoietin↗
PubMed1993

Expression of IGF ligand and receptor genes during preimplantation mammalian development.

The temporal patterns of expression of genes encoding insulin-like growth factor (IGF) ligands and receptors during very early development have been investigated in several laboratories in several different mammalian species. Both reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemical techniques have been used to identify the time of appearance of gene transcripts or end-products. In preimplantation mouse embryos, IGF-II ligand and receptor gene activity is detectable as early as at the two-cell stage, the time when transcription from the embryonic genome is activated, but receptors for insulin and IGF-I are not detectable until the compacted eight-cell stage. Transcripts for insulin or IGF-I are not detectable in preimplantation mouse embryos, although the ligands are present in the reproductive tract. The pattern of IGF gene expression is not, however, identical in all mammalian species. In cow embryos, for example, transcripts for IGF-I and IGF-II ligands and receptors and insulin receptors have been detected at all stages of preimplantation development from mature oocyte to blastocyst (Watson et al., 1992). Attempts to quantitate transcript abundance in these early embryos are in progress in our laboratory. In the preimplantation mouse embryo, transcripts for several different IGF-binding proteins (IGFBP-2, -3, -4, and -6) have been detected by RT-PCR procedures. In addition, transcripts for IGFBPs have been identified in RNA derived from cumulus cells, the ovary, the oviduct, the uterus, and the decidua. These findings suggest that the interactions of IGF ligands and receptors in preimplantation development might, indeed, be modulated by IGFPs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Thermogenic, thermoregulatory and activity effects of fenfluramine, a 5-hydroxytryptamine agonist, in immature domestic fowl (Gallus domesticus).

1. DL-Fenfluramine, a 5-hydroxytryptamine (5-HT) agonist, increases the metabolic rate of the adult domestic fowl and also stimulates heat loss mechanisms. Since thermogenic mechanisms vary qualitatively and quantitatively with age, this series of experiments was designed to measure the effects of fenfluramine on immature, growing, 'broiler' chickens. 2. The work was also designed to distinguish any direct effect of fenfluramine on respiratory quotient (RQ) from the indirect effects of reduced food intake. 3. Female commercial broilers were used (5-7 weeks old; 1.1-1.8 kg), at an ambient temperature of 25 degrees C and on a 14 hr light: 10 hr dark cycle. DL-Fenfluramine was injected intramuscularly at 80 mumol/kg body weight (20 mg/kg), in 0.5 ml of 9 g/l saline per kg bodyweight. 4. When the effects on heat production (H) of differences in food intake were eliminated by fasting, fenfluramine increased H by up to 20% within about 20 min. 5. RQ decreased four times more rapidly after fenfluramine injection than after the control treatment whether the birds were fed or fasted, reaching 0.70 in about 3 hr. 6. Wing-drooping and polypnea occurred within 10 min of injection. Maximal response was in 30 min to 1 hr for polypnea and 30 min to 2 hr for wing-drooping, depending on experimental procedure. Both responses ceased in 5-7 hr. 7. Physical activity was greatly reduced by fenfluramine, particularly in the first 4 hr. This effect occurred whether food was available or not.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Caecal threadworms Trichostrongylus tenuis in red grouse Lagopus lagopus scoticus: effects of weather and host density upon estimated worm burdens.

Trichostrongylus tenuis eggs were counted in faeces from individually marked wild red grouse for 8 years. Egg counts varied seasonally and annually. In some years, a sudden increase in mid-April was consistent with delayed maturation of larvae which had overwintered in the birds in a hypobiotic state. A more gradual increase in summer was probably due to uninterrupted maturation of larvae ingested then. Despite 30-fold year-to-year variation in mean egg counts, relative differences in egg counts among known individuals within years tended to persist across years. Rainfall in previous summers explained much of the year-to-year variation in egg counts, probably because parasite recruitment was greatest during wet summers. Grouse density was only weakly related to worm egg counts. The data were not consistent with the hypothesis that the cyclic-type population fluctuation in red grouse numbers observed at the time of this study was caused by the parasites.

Age Factors↗
PubMed1993

Role of intragastric and intraoesophageal alkalinisation in the genesis of complications in Barrett's columnar lined lower oesophagus.

Patients with Barrett's columnar lined lower oesophagus have severe acid gastrooesophageal reflux and may develop complications, including ulceration, stricture, and carcinoma. The aim of this study was to establish if a relationship exists between the pH profile in the oesophagus and stomach and the development of complications in patients with Barrett's columnar lined lower oesophagus. Twenty four hour ambulatory oesophageal pH monitoring was performed in 26 patients with Barrett's columnar lined lower oesophagus and combined with 24 hour ambulatory gastric pH monitoring in 16. Ten of the 26 with Barrett's columnar lined lower oesophagus had complications including stricture (eight), deep ulceration (one), and carcinoma (one). Oesophageal acid exposure (% time < pH 4) was similar in patients with or without complications (19.2% v 19.3% p > 0.05). Oesophageal alkaline exposure (% time > pH 7) was greater in patients with complications (24.2% v 8.4% p > 0.05). Of the 16 patients who underwent gastric pH monitoring there was a clear relationship between gastric and oesophageal alkalinisation in 13. These results support the hypothesis that complications in Barrett's columnar lined lower oesophagus develop in association with increased exposure of the oesophagus to an alkaline environment which appears to be secondary to duodenogastric reflux. The routine use of 24 hour ambulatory gastric pH monitoring in conjunction with oesophageal pH monitoring can help identify those patients at risk.

Alkalies↗
PubMed1993

Population studies of the fragile X: a molecular approach.

The fragile X mutation can now be recognised by a variety of molecular techniques. We report a pilot screening survey of a population of children with mental impairment in which we used Southern blotting methods to detect the fragile X mutation, augmented by cytogenetic studies on children whose phenotype suggested a possible chromosome abnormality. There were 873 children with special educational needs in our survey and 310 fulfilled our criteria for testing. A sample was obtained from 254, of whom four were found to have a full fra(X) mutation (delta L) and none to have a premutation. The number of CGG repeats in our population of X chromosomes was measured by PCR analysis and the genotype at the closely linked polymorphic locus FRAXAC1 established. The distribution of CGG repeat numbers was very similar to that of the control population reported by Fu et al and the distribution of FRAXAC1 alleles almost identical to that of the control population reported by Richards et al. Among the non-fragile X chromosomes, we found a very significant correlation between the size of the CGG repeat and the FRAXAC1 genotype. There was a dearth of A and D genotypes in subjects with a small number of CGG repeats and an excess of the A genotype in those with a large number of CGG repeats. These observations are considered in the light of the reported disequilibrium between the A (and possibly also the D) genotype and the fra(X) mutation.

Adolescent↗
PubMed1993

Influence of smoking habits on change in carbon monoxide transfer factor over 10 years in middle aged men.

BACKGROUND: Emphysema is associated with a reduction in carbon monoxide transfer coefficient (TLCO/VA), but little is known about the evolution of changes in TLCO/VA in middle aged smokers at risk of developing chronic airflow obstruction. METHODS: TLCO/VA (single breath method) was measured on two occasions 10 years apart in 122 middle aged men. RESULTS: Initially TLCO/VA averaged 97% predicted in never smokers (n = 42, mean age 37.2 years), 99% predicted in ex-smokers (n = 21, mean age 41.9 years), and 85% predicted in those who smoked over 15 cigarettes a day (n = 42, mean age 42.0 years). Mean rates of decrease in TLCO/VA over 10 years, however, were similar in the three groups, so that differences between smokers and non-smokers did not increase during the 10 years. Seventeen men (mean age 40.9 years) who initially were smokers became sustained ex-smokers within two years of the first measurement; in these men mean absolute values of TLCO/VA rose, averaging 89% predicted at the first assessment but 102% predicted 10 years later. CONCLUSION: By the age of about 40 years TLCO/VA was lower in smokers than in never smokers but this difference did not increase over the following 10 years. Sustained ex-smokers had values similar to those of never smokers even when TLCO/VA was known to have been reduced while they were smoking. Changes in TLCO/VA associated with stopping smoking were considerably larger than could be explained by carbon monoxide back pressure, indicating that mechanisms other than irreversible increase in the size of terminal air spaces underlie the lower values in smokers. To detect emphysema in smokers it is necessary to use reference equations that take account of current smoking.

Adult↗