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Biomedical subjects

W Taylor

Publications and source records attributed to W Taylor.

At least 19 recordsLinked to original sources
PubMed1992

Determinants of lung cancer risk among cadmium-exposed workers.

Workers at a cadmium recovery plant in Globe, Colorado, showed an increased risk of lung cancer, which some investigators have attributed to cadmium exposure. We conducted a cohort mortality analysis of this work force and a case-control analysis of the lung cancer cases within this work force in order to assess the probable causes of the lung cancer excess. The Globe plant began as a lead smelter about 1886, switched to arsenic production in 1920, and became a cadmium metal production facility in 1926. Cadmium, arsenic, and cigarette smoking are three potential lung carcinogens found in this workplace. Industrial hygiene data collected from 1943 onward served as the basis for the National Institute for Occupational Safety and Health (NIOSH)-derived exposure algorithm that assigned cadmium exposure estimates to employees based on their work area in the plant and calendar time. Few exposure data existed for substances other than cadmium. Feedstock ore concentrations were used as a surrogate measure of air arsenic levels. The arsenic content of the fines used as feedstock prior to 1940 was considerably higher than that of the fines used after 1940. Smoking histories had been obtained previously for 45% of the workers. A case-control analysis of the 25 cases of lung cancer known to have occurred among these workers through 1982 was conducted using three controls per case, matched by closest data of hire and age at hire. Potential causal agents for lung cancer included cadmium exposure, cigarette smoking, and arsenic exposure. Exposure variables for each case and control included estimated cumulative cadmium exposure in milligram-years per cubic meter, cigarette smoking history, and plant arsenic exposure status at the time of hire. Estimated cumulative cadmium exposures of cases and controls did not differ overall or within the date-of-hire strata. Cases were more than eight times more likely to have been cigarette smokers than were controls. Lung cancer risk in this workplace was more closely related to the period of hire, not to the cumulative cadmium exposure. The period of hire appears to be a surrogate for arsenic exposure as related to feedstock. The measures used here seem to indicate that exposure to arsenic and cigarette particulates, rather than to cadmium particulates, may have caused the increased rate of lung cancer of these workers.

Adult↗
PubMed1992

Diagnostic implications of detection of proteinase K-resistant protein in spleen, lymph nodes, and brain of sheep.

Brain, spleen, and selected lymph nodes from sheep with clinical signs of scrapie were analyzed for presence of proteinase K-resistant protein (PrP-res). Diagnosis of scrapie on the basis of detection of PrP-res was compared with diagnosis on the basis of histologic evaluation of the brain from clinically affected or exposed sheep. Proteinase K-resistant protein was found in every brain that was histologically positive for scrapie, and in addition, was found in the brain of several clinically positive sheep that were not diagnosed as scrapie-positive by histologic evaluation. Proteinase K-resistant protein was also found in 87% of the spleens and lymph nodes from sheep that had PrP-res detected in brain homogenates. Therefore, analysis of sheep brain, spleen, or lymph nodes for PrP-res provided a diagnostic approach that was superior to histologic examination alone for detection of naturally scrapie agent-infected sheep.

Animals↗
PubMed1991

Lessons from hand-arm vibration syndrome research.

This paper addresses many of the salient issues and difficulties encountered in performing Hand-Arm Vibration Syndrome research since its discovery in the early 1900's by Alice Hamilton. The areas discussed and the resulting lessons learned include the medical, epidemiological, and control aspects of HAVS. The authors conclude with a plea to health professionals to be ever vigilant and responsive to the HAVS problem, or else it will continue unabated into the next century, an overall time span of nearly 100 years.

Arm↗
PubMed1991

Practical 3-D radiotherapy planning of brain tumors.

In postoperative radiotherapy of brain tumors it is usually the case that preoperative imaging studies, either CT or MRI, were performed outside of the purview of the radiation therapy department. Thus the target volume is defined in an imaging study that does not lend itself readily for entry to a 3-D treatment planning system. A method is described that adjusts the patient structure defined by scan data to an appropriate position for radiotherapy. Software tools that are simple to use have been incorporated in a 3-D treatment planning program that allows oblique treatment planes to be defined. The program provides beam's-eye-view plots of the fields that are used to overlay simulation films and will automatically describe a field blocking outline that provides a prescribed margin on the target volume or other structures that have been defined. Finally, dose calculations in arbitrary planes through the head are made and isodose plots produced.

Brain Neoplasms↗
PubMed1991

Physical activity, cardiovascular fitness, and adiposity in children.

With cardiovascular fitness (CVF) as the dependent variable, relationships with habitual level of physical activity, age, gender, and body mass index (BMI) were investigated in a sample of 93 high adiposity and 93 low adiposity children, ages 8 to 13. A physical activity score (PAS) was computed for each child from a 2-day observation period. A physical working capacity index from cycle ergometry (PWC170) was the measure of CVF. Low and high adiposity samples were classified by a median split (42.9 mm) on the sum of three skinfold measures (tricep, suprailiac, subscapula). For the high adiposity sample, PAS, age, BMI, and gender were significant and the overall model was significant (p less than .001), accounting for 38% of variance in PWC170. In the low adiposity sample, gender (p less than .04) was significantly related to CVF, but the overall model was not significant (p less than .35). PAS, thus, was a significant predictor of CVF among the high adiposity children, but not the low adiposity children. Mechanisms that may account for this difference include greater work for equal activity among the obese, a ceiling effect on CVF among the low adiposity children, or differences in hormonal or metabolic factors mediating the activity-CVF relationship.

Adolescent↗
PubMed1991

Hand-arm vibration syndrome: clinical evaluation and prevention.

Increasing recognition by workers that blanching of their fingers may be due to hand-arm vibration exposure from the tools they use at work and their consequent claims for compensation emphasize a need for better clinical evaluation and prevention. We describe the symptoms and signs, and enumerate the diagnostic procedures (both screening and laboratory) necessary to establish the diagnosis and severity grading of subjects with hand-arm vibration syndrome. Although effective treatment of the condition other than avoidance of further vibration exposure is still being researched, prevention is all important. The necessary steps are identified.

Hand↗
PubMed1991

Sleep and nocturnal acid reflux in normal subjects and patients with reflux oesophagitis.

Nocturnal gastro-oesophageal reflux may be important in the pathogenesis of reflux oesophagitis. This study aimed to determine whether: (1) gastro-oesophageal reflux occurs during sleep in patients with reflux oesophagitis and, if so, to explore the mechanism, and (2) the sleep pattern of patients with oesophagitis is different from that of control subjects. After a standard evening meal, simultaneous manometric, oesophageal pH, and polysomnographic recordings were obtained in 11 patients with endoscopic oesophagitis and 11 control subjects. Patients with gastrooesophageal reflux disease had significantly more total reflux episodes throughout the nocturnal monitoring period than control subjects (105 v 6). Ninety two of 105 episodes of gastro-oesophageal reflux in patients occurred during the awake state and 10 during sleep stage II. A number of reflux episodes occurred during brief periods of arousal from the various sleep stages. Of the 105 reflux events recorded in patients, 42 were induced by transient lower oesophageal sphincter relaxation, 20 by stress reflux, 22 by free reflux mechanisms, and in 21 the mechanism was unclear. The sleep pattern and the time spent in each sleep stage was not different between the two groups. It is concluded that the awake state is crucial for the occurrence of nocturnal reflux episodes in normal subjects as well as in patients with reflux oesophagitis and that the difference between the frequency of gastro-oesophageal reflux between normal subjects and patients cannot be explained by different sleep patterns.

Adult↗
PubMed1991

Medullary carcinoma of the thyroid presenting as multifocal bronchial carcinoid tumour.

A 21 year old man presented with diarrhoea and flushing after meals and later developed miliary shadowing on his chest radiograph. Multifocal bronchial carcinoid tumour was diagnosed initially, but at necropsy metastatic medullary carcinoma of the thyroid was found. Multifocal bronchial carcinoid tumour should not be accepted as a primary diagnosis without first excluding medullary carcinoma of the thyroid because of the need to screen relatives of affected patients.

Adult↗
PubMed1991

Pneumothorax and malignant mesothelioma in patients over the age of 40.

Five patients over the age of 40 with malignant mesothelioma of the pleura presented with a spontaneous pneumothorax in the course of five years. The diagnosis of malignant mesothelioma was not suspected at surgery but was made by histological examination of the pleurectomy specimens. During this time 91 pleurectomies for recurrent pneumothorax were performed, 45 in patients over the age of 40; malignant mesothelioma therefore accounted for 11% of spontaneous pneumothorax requiring pleurectomy in this age group. The association of spontaneous pneumothorax and malignant mesothelioma is not emphasised in current publications. These five cases highlight the need for all pleurectomy specimens in cases of spontaneous pneumothorax to be sent for histological examination and for a full occupational history to be taken, especially in older patients.

Adult↗
PubMed1991

Long-term outcome following anterior cerebral artery ligation for ruptured anterior communicating artery aneurysms.

The long-term prognosis (15 years) was determined for 17 patients who had undergone anterior cerebral artery (ACA) ligation as the sole treatment for an anterior communicating artery aneurysm. The number of early and late rebleeds was lower than expected from previously ruptured aneurysms. Late ischemia was not a major complication while late postoperative epilepsy occurred in 19% of survivors. In a review of previously published series, ACA ligation appears to have significantly reduced the rates of both early and late rebleeding. This study helps to define the late results of "conservative" operations for ruptured aneurysms.

Cerebral Angiography↗
PubMed1990

A comparison of a controlled release (CR/ZOK) formulation of metoprolol, once daily, with conventional metoprolol tablets, twice daily, in mild to moderate hypertension.

In a randomized double-blind multicenter study in 100 hypertensive patients, the effect of once daily (od) dosing with a new controlled release (CR/ZOK) formulation of metoprolol was compared with that of twice daily (bid) dosing with metoprolol conventional tablets. Eligible patients had a resting seated diastolic blood pressure (DBP) greater than or equal to 95 mm Hg and less than 110 mm Hg at the end of a 6-week open placebo run-in. The active treatment phase lasted 8 weeks. The starting dose was 100 mg od in the CR/ZOK group (N = 53) and 50 mg bid in the tablet group (N = 47). The dose was increased to 200 mg od and 100 mg bid, respectively, in nonresponders (DBP greater than 95 mm Hg) at the end of the first 4-week period. Approximately 40% of both groups received concomitant diuretic therapy throughout the study. The SBP, DBP and HR were reduced compared to baseline in both treatment groups after 4 and 8 weeks. After 4 weeks, 85% of the CR/ZOK group and 74% of the tablet group had DBP less than 95 mm Hg. After another 4 weeks, the corresponding figures were 93% and 93%. There was no statistically significant difference between the treatment groups in the decrease in either SBP, DBP or HR, nor was there any difference in the percentage of responders. Both treatments were equally well tolerated. In conclusion, the antihypertensive effect of once daily dosing (100-200 mg) with the new CR/ZOK formulation of metoprolol is as effective as that of twice daily dosing (50-100 mg) with conventional metoprolol tablets.

Adult↗
PubMed1990

Sequencing and characterization of the 185 kDa cell surface antigen of Streptococcus mutans.

The gene spa P (formerly designated as spa P1) encoding the Mr 185,000 surface antigen I/II of Streptococcus mutans, serotype c (strain NG5) has been sequenced. The deduced amino acid sequence of antigen I/II (1561 residues) includes a putative signal peptide (residues 1-38), as well as a transmembrane region (residues 1537-1556). The N-terminal part of the protein (residues 39-550) is particularly rich in alanine and includes three tandem repeats of a sequence of 82 residues. This region is predicted to be alpha-helical, adopting a coiled-coil formation, and may account for the cell surface hydrophobicity associated with expression of antigen I/II. In contrast the C-terminal region (residues 800-1549) is proline-rich, favouring an extended conformation. Comparison with the sequence determined from Strep. mutans strain MT8148 showed that antigen I/II is highly conserved with the exception of a short central region (residues 750-805). N-terminal sequencing of purified antigens I and II components indicated that antigen I extends from the amino-terminus of the intact Mr 185,000 surface antigen while antigen II extends from residue 996.

Amino Acid Sequence↗
PubMed1990

Prevalence survey of cytomegalovirus infection in children in Chengdu.

Cytomegalovirus (CMV) is a common worldwide perinatal infection. Although usually asymptomatic, it may cause deafness in up to 15% of these infants. A cross-sectional study was performed to determine the age-specific prevalence of CMV seropositivity in Chinese children and to determine if any risk factors for infection could be identified. In a two-stage sampling procedure, nine districts were randomly selected from 70 citizenship districts in Chengdu, Sichuan Province, People's Republic of China. Then, 1,950 households were randomly selected from 11,886 households and interviewed. Blood was obtained from all children aged less than seven years and assayed using an enzyme-linked immunosorbent assay method. A subgroup of sera was retested at the research laboratory and also sent to the National Reference Laboratory in Beijing. Kappa values for the test agreement with the reference laboratory and retesting within the study laboratory were 0.94 and 0.86, respectively. Seropositivity averaged 52% in those aged less than one year and 60% in those between four and seven years. A higher rate of seropositivity was observed in urban versus rural children (odds ratio (OR) = 2.55), breast feeding in urban areas only (OR = 1.87), and day care versus home care setting (OR = 1.59). High CMV seroprevalence, even in the first year of life, was observed in this population of well children in Chengdu, China. An association was observed between seroprevalence and residence, method of feeding, and day care attendance.

Bottle Feeding↗
PubMed1990

Metastatic cutaneous malignant melanoma of the vitreous and retina.

A case of cutaneous malignant melanoma metastasising to the retina in a 71-year-old patient who presented with vitreous opacities is discussed. In view of the increasing incidence of cutaneous malignant melanoma in our community the possibility of ocular metastases merits consideration.

Aged↗
PubMed1990

Appropriate and inappropriate neuroendocrine products in pulmonary tumourlets.

Pulmonary tumourlets are focal aggregates of neuroendocrine cells that occur in the periphery of the lung and may be associated with chronic inflammation and scarring. Six such lesions were seen in five lungs from a series of 35 pairs of lungs studied at necropsy. All were immunoreactive for neurone-specific enolase, protein gene product 9.5, and a range of neuroendocrine products. Of the peptides found in neuroendocrine cells in normal human lungs, gastrin releasing peptide was present in all tumourlets and calcitonin in all but one; none contained leucineenkephalin. Of a series of peptide and protein hormones not present in the neuroendocrine cells of healthy human lungs, growth hormone was present in all six tumourlets and adrenocorticotrophin in two. Identical patterns of peptide expression were displayed by neuroendocrine cells in the airway associated with the tumourlets in two cases. Such cells were increased in number and abnormally clustered. Aberrant expression of peptides might accompany the morphological changes in the pulmonary neuroendocrine cells seen in diseased lungs, their florid focal proliferation occasionally resulting in the formation of a tumourlet.

Aged↗