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Biomedical subjects

J B Hazelrig

Publications and source records attributed to J B Hazelrig.

7 recordsLinked to original sources
PubMed1992

Fractal dimension from radiographs of peridental alveolar bone. A possible diagnostic indicator of osteoporosis.

The purpose of this study was to investigate whether a radiographic estimate of osseous fractal dimension is useful in the characterization of structural changes in alveolar bone. Ten dry mandibular bone segments were radiographed from three controlled projection angles (-5, 0, +5 degrees), before and after acid-induced partial decalcification. Fractal dimension was estimated by regression analysis of power spectra computed by Fourier transform of selected regions of interest in digitized images of the radiographs. Repeated-measures ANOVA showed that fractal dimension so determined varied over anatomic locations (p less than .01), but increased after acid-induced demineralization (p less than .0005), irrespective of the radiographic projection angles (p greater than .99). In vivo fractal dimension was computed from randomly selected intraoral radiographs of six premenopausal (ages, 32.8 +/- 3.9) and six postmenopausal (ages, 62.5 +/- 4.1) women. A significantly (p less than .01) higher fractal dimension was observed in the older group.

Adult↗
PubMed1992

Turnover of synthetic class A amphipathic peptide analogues of exchangeable apolipoproteins in rats. Correlation with physical properties.

Peptide analogues of the class A amphipathic helixes from exchangeable apolipoproteins mimic apolipoprotein (apo) A-I in a number of ways, including the ability to activate the enzyme lecithin:cholesterol acyltransferase, to associate with high density lipoproteins (HDLs), and to form HDL-like particles in the presence of lipids. This study investigated the metabolic properties of several of these peptide analogues in the rat. Peptide analogues studied were 18A (referred to as L-18A to differentiate it from D-18A, and which mimics apolipoprotein amphipathic helical domains in its charge distribution), 37pA (a dimer of two 18A monomers separated by a proline), 18R (with reversed charge distribution compared with 18A), and D-18A (identical in amino acid sequence to 18A but synthesized from D-amino acids). Peptides were radiolabeled with 125I. In addition, metabolism of rat and human 125I-apo A-I and human 14C-apo A-I was studied; no significant differences in clearance of these preparations were seen. Clearance data were fitted to multiexponential equations to give half-times of clearance; biexponential equations consistently provided the best nonlinear least-squares curve fit. The order of relative lipid affinity determined in vitro was 37pA greater than apo A-I greater than D-18A = L-18A greater than 18R. Half-times of clearance were in the same approximate rank order: 37pA, 6.9 +/- 3.3 hours (mean +/- SD); apo A-I, 6.9 +/- 1.8 hours; D-18A, 4.0 +/- 1.0 hours; L-18A, 4.6 +/- 1.6 hours; and 18R, 0.9 +/- 0.1 hour.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗
PubMed1989

Glycemic responses in insulin-dependent diabetic patients: effect of food composition.

This study examined the hypothesis that the glucose component of food and not the total carbohydrate is the major determinant of the glycemic response in patients with insulin-dependent diabetes mellitus. Patients were given glucose alone, fructose alone, glucose + fructose, lactose, and glucose + fat + protein. Fructose given alone increased the blood glucose almost as much as a similar amount of glucose (78% of the glucose-alone area, p less than 0.05). However, the same amount of fructose given with glucose produced no greater glycemic response than did glucose alone (108%). Similarly, galactose contributed only slightly to the glycemic response when given as lactose (122%, p less than 0.01) whereas protein and fat had no additional glycemic effect (101%). To test the above hypothesis in natural foods, patients were fed an amount of bread (high glycemic index) or apple (low glycemic index) that contained 25 g glucose. Both challenges produced glycemic responses very similar to 25 g purified glucose.

Adult↗
PubMed1979

Survival and probability of cure without and with operation in complete atrioventricular canal.

Actuarial analysis based on postmortem examination of patients who had been treated nonsurgically for complete atrioventricular (A-V) canal defect shows that only 54% survive to 6 months of age, 35% to 12 months, 15% to 24 months, and 4% to 5 years of age. Our surgical experience since 1975 in 39 patients confirms the idea that primary repair is feasible in small infants. The highest risk of hospital death is when the operation is done in the early months of life; it falls to 17% by age 12 months. Between 1967 and October, 1976, the five-year survival rate among patients leaving the hospital alive after repair was 91%. The age-specific probability of "surgical cure" of patients operated upon for complete A-V canal (alive five years later with mean pulmonary artery pressure less than 25 mm Hg) is maximal at 73% when the operation is done at about 14 months of age. Urgent earlier repair is frequently necessitated by the life history of the disease.

Age Factors↗
PubMed1978

Life expectancy without surgery in tetralogy of Fallot.

All published autopsy cases of patients with tetralogy of Fallot who died without surgical treatment were studied to determine the life expectancy of such persons. In addition, the data from a study of persons with tetralogy alive in Denmark in 1949 were reanalyzed. The survival data from these two sources were remarkably similar, indicating that 66 percent of persons with tetralogy of Fallot not treated surgically live to age 1 year, 49 percent to age 3 years and 24 percent to age 10 years; thereafter, the hazard function (or instantaneous risk of death) remains constant. The chance of survival is significantly less when pulmonary atresia, rather than stenosis, is present.

Adolescent↗