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Biomedical subjects

F B Smith

Publications and source records attributed to F B Smith.

At least 37 records · Page 2Linked to original sources
PubMed1995

EM mixed model analysis of data from informatively censored normal distributions.

Maximum likelihood techniques using the EM algorithm are applied to correlated normally distributed survival data from a placebo-controlled, double-blind, dose-ranging crossover study to assess the short-term efficacy of an antianginal drug in patients with chronic stable angina. Censoring was informative and nonterminal and was not due to death or withdrawal from the study. Unlike previous approaches these techniques are mathematically and computationally tractable, do not require computations of high-dimensional integrals, and do not require the inversion of large matrices.

Algorithms↗
PubMed1994

Relationship between plasma essential fatty acids and smoking, serum lipids, blood pressure and haemostatic and rheological factors.

We aimed to determine whether levels of plasma fatty acids are correlated with other potential risk factors for cardiovascular disease, using a sample of patients from a cross-sectional survey of the general population, in the City of Edinburgh. 306 men and women aged 55-74 years of whom half had clinical evidence of arterial disease were tested. The main outcome measures were plasma fatty acids and potential risk factors for cardiovascular disease (age, sex, smoking, blood pressure, serum cholesterol, HDL cholesterol (HDL-C), triglycerides (TGs), lipid peroxides (LPx), plasma fibrinogen, von-Willebrand factor (vWf), beta-thromboglobulin (beta TG), cross-linked fibrin degradation products (FIBDP) and plasminogen activator inhibitor PAI). High levels of several known risk factors for cardiovascular diseases were associated with low levels of certain essential fatty acids. Eicosapentaenoic (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) were negatively associated with smoking and TG levels. High levels of certain haemostatic factors, including plasma fibrinogen, blood viscosity and LPx were also associated with low levels of EPA, DHA, AA and HDL-C. In conclusion, plasma fatty acids show strong correlations with many potential risk factors for cardiovascular disease, emphasising their possible importance in pathogenesis.

Aged↗
PubMed1994

Plasma essential fatty acids, cigarette smoking, and dietary antioxidants in peripheral arterial disease. A population-based case-control study.

The aim of this study was to determine the levels of plasma fatty acids in patients with peripheral arterial disease and in control subjects and to identify whether any risks of disease related to these differences were influenced by smoking and antioxidant intake. A random sample of 1592 men and women aged 55 to 74 years was selected from the general population (the Edinburgh Artery Study), from which 153 cases of peripheral arterial disease were identified by the presence of intermittent claudication and low ankle systolic pressures at rest and during reactive hyperemia; these were matched by age and sex to 153 control subjects with no evidence of cardiovascular disease. In 113 case and 122 control subjects, fatty acid levels were measured in three plasma fractions (triglyceride, cholesteryl ester, and phospholipid), and smoking habits and dietary antioxidant intake were determined by questionnaire. Arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid, and docosapentaenoic acid (DPA/n-3) were significantly lower in the cases than controls (P < .01). More case than control subjects were current or exsmokers (86% versus 50%; P < .001), and the case subjects had lower vitamin C intake (64.8 mg versus 71.1 mg; P < .05). By logistic regression adjustment for smoking and vitamin C intake, only DPA/n-3 (odds ratio, 0.19; P < .01) and arachidonic acid (odds ratio, 0.44; P < .05) remained significantly related to disease; only DPA/n-3 reduced the risk associated with smoking. We conclude that in subjects with peripheral arterial disease compared with healthy control subjects, the largest differences occurred in fatty acids of the n-3 series, particularly DPA/n-3.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Effects of visible and invisible orofacial defects on self-perception and adjustment across developmental eras and gender.

Self-ratings of satisfaction with appearance and accomplishment of psychosocial tasks were examined by age and gender among school aged children with visible defects (cleft lip and/or palate, n = 272), or invisible defects (cleft palate only, n = 159), and dental patients (n = 128) without clefts. Using weighted least squares ANOVA and logistic regressions, the results revealed that subjects with visible defects expressed greater dissatisfaction with their appearance than those subjects with invisible defects (p < .001). Subjects with invisible defects consistently expressed lower problem solving ability than subjects with visible defects (p < .001) and dental patients with no defects (p < .05). Both groups with clefts expressed less social independence (p < .001); and subjects with clefts reported having more friends than other children (p < .01). Implications for clinicians and further research are discussed.

Adolescent↗
PubMed1993

Smoking, haemostatic factors and lipid peroxides in a population case control study of peripheral arterial disease.

The aim of this study was to determine differences between cases of peripheral arterial disease and healthy controls in levels of haemostatic factors and lipid peroxides and the influence of cigarette smoking. The study groups were selected from the Edinburgh Artery Study which is a random sample survey of men and women aged 55-74 years. Mean levels of plasma fibrinogen, von Willebrand factor, beta-thromboglobulin, plasminogen activator inhibitor (type I), cross-linked fibrin degradation products and lipid peroxides were markedly elevated in 121 study cases compared with 126 age- and sex-matched controls. For example, cross-linked fibrin degradation products had a geometric mean of 106.8 ng/ml (95% confidence interval (CI) 95.3, 119.8) in study cases and 74.7 ng/ml (95% CI 67.0, 83.4) in controls (P < 0.001). Inclusion of smoking in logistic regressions of each factor on peripheral arterial disease significantly reduced the odds of disease for von Willebrand factor and for cross-linked fibrin degradation products, but had little effect on the increased odds associated with fibrinogen, beta-thromboglobulin, plasminogen activator inhibitor and lipid peroxides. We conclude that, in men and women in Edinburgh, peripheral atherosclerosis is associated with lipid peroxidation, endothelial disturbance, platelet activation, elevated fibrinogen, fibrin formation and increased inhibition of fibrinolysis. The most important effects of cigarette smoking in promoting atherosclerosis may be endothelial disturbance and fibrin formation.

Aged↗
PubMed1993

Localized pleural microdeposition of type A amyloid in a patient with rheumatoid pleuritis. Histologic distinction from pleural involvement in systemic amyloidosis.

Decorticated pleural tissue from a 74-year-old man with rheumatoid arthritis, an exudative pleural effusion, and normal left ventricular function contained microscopic deposits of amyloid A protein, localized to the interface between a deep layer of dense fibrocollagen and a layer of granulation tissue beneath a surface fibrin exudate. Previously reported instances of pleural amyloid deposition have occurred in patients with presumed systemic amyloidosis, and most such effusions are the result of congestive heart failure. This patient had no evidence of systemic amyloidosis, and this case appeared to be an example of an unusual form of localized amyloidosis, so-called periinflammatory amyloidosis A. These observations suggest that amyloid in a pleural biopsy should not be construed per se to be diagnostic of systemic amyloidosis.

Aged↗
PubMed1993

The relationship between blood viscosity and blood pressure in a random sample of the population aged 55 to 74 years.

Blood viscosity is elevated in hypertensive subjects, but the association of viscosity with arterial blood pressure in the general population, and the influence of social, lifestyle and disease characteristics on this association, are not established. In the Edinburgh Artery Study, 1592 men and women aged 55-74 years selected randomly from the general population attended a university clinic. A fasting blood sample was taken for the measurement of blood viscosity and its major determinants (haematocrit, plasma viscosity and fibrinogen). Systolic pressure was related univariately to blood viscosity (P < 0.001), plasma viscosity (P < 0.001) and plasma fibrinogen (P < 0.01), but the association with fibrinogen did not persist after adjusting for body mass index. Diastolic pressure was related univariately to blood viscosity (P < 0.001) and plasma viscosity (P < 0.001) and haematocrit (P < 0.001) but not to fibrinogen. The only difference between the sexes was that the association between blood viscosity and systolic pressure was confined to males. Blood viscosity was associated equally with systolic and diastolic pressures in males, and remained independently related on multivariate analysis adjusting for age, sex, body mass index, social class, smoking, alcohol intake, exercise, angina, HDL and non-HDL cholesterol, diabetes mellitus, plasma viscosity, fibrinogen, and haematocrit.

Aged↗
PubMed1993

Relationships between image cytometric DNA index, proliferation fraction and multiploidy and conventional nuclear grade in breast carcinoma.

High nuclear grade, DNA aneuploidy, and elevated proliferation fraction tend to be mutually associated in breast carcinomas, defining a subset of carcinomas with more aggressive behavior. We sought to examine more closely the interrelations between nuclear grade and DNA cytometric parameters (aneuploidy, proliferation fraction, and multiploidy) in breast carcinomas based on our assumption that DNA content is the major determinant of nuclear appearances used in grading tumors. We obtained estimates of the strength of correlation (correlation and contingency coefficients) between nuclear grade and DNA index, proliferation fraction, and multiploidy within a series of 87 consecutively accessioned breast carcinoma specimens studied by conventional histologic methods and by computer-assisted image analysis of Feulgen-stained imprints. Seventy-three tumors were found to consist of a single population of cells on the cytogram (uniploid tumors). In this group, DNA index of the population and proliferation fraction were separately compared with nuclear grade by rank-order correlation. The Spearman correlation coefficient (Rs) for nuclear grade versus DNA index was 0.55 (P < 0.00006), the highest level of correlation observed between any of the parameters studied. Tumors given a nuclear grade of 1 were mostly diploid or near diploid, and Grade 3 tumors were predominantly aneuploid. However, nuclear grading did not effect a complete separation of diploid from aneuploid tumors, because assignment of intermediate grades (almost one half of the specimens) had no value in predicting ploidy status.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1992

Fibrinogen genotype and risk of peripheral atherosclerosis.

There is conflicting evidence about the influence of fibrinogen genotype on plasma fibrinogen concentrations, and the relation between genotype and atherosclerotic disease has not been studied. In a population-based case-control study we aimed to find out whether certain fibrinogen genotypes are associated with an increased risk of peripheral atherosclerosis. 121 subjects with peripheral arterial disease and 126 healthy controls matched for age and sex were selected from a random population sample aged 55-74 years in the Edinburgh Artery Study. Mean fibrinogen concentrations were higher in cases than in controls (3.12 [95% confidence interval 2.99-3.26] vs 2.75 [2.64-2.85], p less than 0.001). A greater proportion of cases than controls were homozygous or heterozygous for an allele at the beta fibrinogen locus (4.2 kb allele, Bcl I digestion); the allele frequency was 0.197 in cases and 0.097 in controls (p less than 0.005). Extended haplotypes for 4.2 kb heterozygotes were also associated with an increased risk of peripheral arterial disease. However, haplotype had only a small effect on the association of plasma fibrinogen concentration with disease, and the relation of haplotype with disease was independent of age, sex, social class, smoking status, plasma fibrinogen, alcohol consumption, body mass index, and diabetes mellitus. We conclude that variation at the beta fibrinogen locus is associated with an increased risk of peripheral atherosclerosis. The influence is not mediated simply by way of increased fibrinogen concentrations but could be due to a structurally variant fibrinogen or linkage disequilibrium with a neighbouring gene.

Aged↗
PubMed1992

Validity of duplex scanning in the detection of peripheral arterial disease in the general population.

Duplex scanning has the potential to identify asymptomatic atherosclerosis of the lower limbs in the general population. The aim of this study was to assess the validity of scanning in a group of men and women aged 55-74, sampled from a population survey. Disease was measured using the WHO questionnaire on claudication, the ankle brachial pressure index, and a reactive hyperaemia test. In 73 cases of peripheral arterial disease and 91 controls, a duplex scan was conducted on both legs from the inguinal ligament to the lower popliteal region. The two radiologists performing the scans were blind to the arterial status of the subjects. Interpretation of the image, waveform and peak systolic velocity resulted in a sensitivity of 78%, specificity of 65% and positive predictive value of only 19%. The image alone had the best positive predictive value (62%) and specificity (97%). These results suggest that duplex scanning may currently be of limited use as a diagnostic screening test in the general population. Interpretation of the image alone, however, may be useful in some settings in identifying healthy subjects free of disease.

Aged↗
PubMed1992

The effects on toxicity of circadian patterning of continuous hepatic artery infusion.

Long term continuous hepatic artery infusion of FUDR was carried out in 34 rats. In the animals who received a constant infusion schedule of 15 mg/kg/day all died of toxicity with a mean survival of 9.3 days. If the pattern of the continuous infusion was changed so that over 60% of the infusion was given during the hours of 3pm to 9pm than all of the animals survived the 14 day infusion. If the maximum dose of infusion was changed so that 60% of the infusion was given at night from 3am to 9am the infusion became more toxic and all the animals died in a mean of 5.5 days. Pathologic sectioning of all the livers reflected the above outcomes with the greatest amount of hepatic necrosis in the animals on the night cycles. This study underscores the recent advances in chronobiology demonstrating that for continuous hepatic arterial infusions the timing of delivery is crucial in determining the toxicity.

Animals↗
PubMed1992

Habilitation of patients with clefts: parent and child ratings of satisfaction with appearance and speech.

This study examined ratings regarding satisfaction with facial appearance and speech performance from 495 parent-child pairs. Data were obtained from school-aged children (5-18 years old) and their parents using standardized independent interviews. Results revealed that 54 percent of the children with cleft lip (CL) or cleft lip and palate (CLP) were very pleased with their appearance, and 62 percent of the cleft palate or CLP subjects were very pleased with speech. Low, but statistically significant correlations exist between the female subjects and their parents in satisfaction with appearance. Although older cleft lip and/or palate patients reported increased satisfaction with speech, no age differences in patient satisfaction with appearance were observed in subjects with CL/CLP. Parents of females expressed more concern about their daughters' appearance than parents of males, while parents of males were more concerned about speech. Implications for craniofacial habilitation teams and research suggestions are discussed.

Adolescent↗
PubMed1992

Genetic variation at fibrinogen loci and plasma fibrinogen levels.

In view of the controversy regarding genetic variation at the fibrinogen loci and plasma fibrinogen levels, we have analysed DNA polymorphisms at the alpha (TaqI), beta (BclI and HaeIII), and gamma (KpnI/SacI) fibrinogen loci in 247 subjects whose plasma fibrinogen was determined by clotting and nephelometric assays. Strong linkage disequilibrium was found between the alpha/TaqI and gamma/KpnI/SacI markers and between the beta/BclI and beta/HaeIII markers. A lesser association was found between the alpha/TaqI and beta/BclI loci, beta/BclI and gamma/KpnI/SacI markers, alpha/TaqI and beta/HaeIII markers, and the gamma/KpnI/SacI and beta/HaeIII markers. This is consistent with the known physical order of these loci and suggests a relative excess of recombination in the alpha/gamma to beta interval. Plasma fibrinogen levels, by either assay method, when corrected or uncorrected for age, sex, and smoking habit, did not show any statistically significant associations with the four fibrinogen polymorphisms examined at the alpha, beta, and gamma fibrinogen loci either singly or when analysed as a haplotype.

Blotting, Southern↗
PubMed1991

Localized Aspergillus infestation in primary lung carcinoma. Clinical and pathological contrasts with post-tuberculous intracavitary aspergilloma.

Saprophytic infestation with Aspergillus was observed in pathologic specimens of primary squamous cell lung carcinoma. In one case, the fungus grew in cystic scarred parenchyma and bronchi distal to an obstructing carcinoma of a segment bronchus. In the other, fungi colonized the inner surface of a peripheral cavitary carcinoma. Neither patient had roentgenographic evidence of aspergilloma and neither experienced severe pulmonary hemorrhage or other complications attributable to the presence of fungus. Although both specimens showed colonizing growth within the abnormal air spaces, in neither had the colonies detached to form a separate intracavitary fungus ball. These patients, and eight patients with similar lesions reported in the literature, demonstrate that Aspergillus colonization of a lung neoplasm frequently lacks one or both of the features characteristic of post-inflammatory intracavitary aspergilloma, a loose fungus ball and antifungal serum antibodies. No patient, to date, has developed massive hemorrhage as a complication of this lesion.

Aspergillosis↗