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Biomedical subjects

J C Rice

Publications and source records attributed to J C Rice.

At least 91 records · Page 5Linked to original sources
PubMed1987

Hemodynamic assessment of high-compression hosiery in chronic venous disease.

Graded high-compression support hosiery have long been recognized as a physiologically significant mode of therapy for chronic venous disease because of their effects on the hemodynamics of venous return. Photoplethysmography (PPG) in the noninvasive vascular laboratory is now recognized as a quick, simple, and noninvasive measurement technique, which correlates well with ambulatory venous pressure in the postphlebitic limb with chronic venous insufficiency. The purpose of this study was to evaluate the hemodynamic effects, as measured by PPG, of 40 mm Hg graded compression support hosiery in the treatment of patients with a documented history of hospital-treated thrombophlebitis. Fifty lower extremities among 38 patients with a documented history of deep vein thrombosis and chronic venous insufficiency were matched against 50 control extremities among patients without disease. All 50 lower extremities in the study group had abnormal noninvasive venous studies, including Doppler ultrasound examination, phleborheography, and PPG (mean, 5.9. seconds). Thus these patients were ascertained to have incompetent deep venous systems, but with normal arterial flow as documented by ankle:brachial ratios. After application of 40 mm Hg gradient compression stockings to the study group, PPG measurements in all 50 limbs initially converted to normal (20.6 seconds). Abnormal PPG measurements were converted to normal in postphlebitic limbs with the application of graded compression stockings in the 29 patients who wore the prescribed hosiery; 21 patients did not wear the gradient stockings after the initial evaluation(s) and were not found to have improved PPG measurements. It can be concluded that such gradient stockings should be associated with a reduction in ambulatory venous pressure, which may, in turn, lead to clinical prevention or improvement of the various sequelae associated with chronic venous hypertension.

Adult↗
PubMed1987

Factors affecting individual injury experience among petroleum drilling workers.

To identify factors affecting the number of injuries experienced by petroleum drilling workers, we carried out a 44-month incidence density study on a cohort employed in January 1979 on mobile drilling units in the Gulf of Mexico. To control for job-related hazards, we computed a standardized ratio of observed to expected injuries for each worker based on his job history. The effect of personal and work history factors was then examined using analysis of variance. Age, rate of job changes, and rate of rig transfers had independent effects on injury rates. Length of service had little effect when age was controlled. The findings suggest that younger workers under stress such as job change may be more susceptible to injury than older workers, regardless of job. If so, targeted changes in procedures and environment which protect workers of all ages are important alternatives to reliance on supervision and experience in injury reduction.

Accidents, Occupational↗
PubMed1986

Topical minoxidil for male pattern baldness.

Significant hair growth occurred in 53% of the 81 patients completing a 1 year trial of topical minoxidil. The average reduction in the diameter of the balding crown was 3.48 cm for all patients. There were no minoxidil related changes in laboratory tests during the study period. Psychosocial studies of our patients indicate that 95% assessed the effectiveness of topical minoxidil as moderate or excellent. The majority of those participating in the study thought that their personal presentation of self was of equal or greater importance than their work performance. It was concluded that topical minoxidil has the potential to improve male pattern baldness significantly without apparent risk and to be a means by which individual presentation of self may be improved.

Adult↗
PubMed1986

Antianginal effects of clonidine.

The effects of clonidine, a central alpha-adrenoceptor agonist, were studied in 12 patients with chronic stable effort angina pectoris in an 18-week randomized, double-blind, two-period (6 weeks each) crossover study with a 3-week inter-period washout phase. Clonidine (200 micrograms as a single dose) produced a decrease in rate-pressure product at rest and during exercise and an increase in exercise tolerance, at 1 and 2 h after administration. Chronic administration of clonidine produced a decrease in rate-pressure product at rest and during exercise and an increase in exercise tolerance after 3 weeks (200 micrograms twice a day) and 6 weeks (400 micrograms twice a day) of treatment.

Angina Pectoris↗
PubMed1985

The mechanical properties of immature osteopetrotic bone.

The elastic properties of the longer bones of the fore and hind limbs of an osteopetrotic Angus calf were measured using an ultrasonic technique. The same bones of a second Angus calf with unaffected bone tissue were also studied. The osteopetrotic bones were found to exhibit statistically significant lower values of density and mineral content than did the unaffected bones (P = .0054 and P = .0492, respectively). This result is contrary to what has been reported in the literature. The variations of the elastic properties and the density around the circumference of both the immature osteopetrotic femur and the unaffected femur were found to be similar to those previously measured on normal adult bovine femora.

Animals↗
PubMed1985

The bone tissue of the canine mandible is elastically isotropic.

This paper reports experimental measurements which show that canine mandibular bone tissue is elastically isotropic. Earlier work has established that human, canine and bovine cortical bone tissue of the femur, tibia and skull are elastically anisotropic and therefore the reported isotropy of mandibular tissue was unexpected. The isotropic elastic moduli of the canine mandible are represented by a Young's modulus of 7.5 GPa and a Poisson's ratio of 0.4. Earlier work gave the three orthotropic Young's moduli of the cortical one of the canine femur as 12.8 GPa, 15.6 GPa and 20.1 GPa. The experimental technique employed is elastic wave propagation at ultrasonic frequencies.

Animals↗
PubMed1985

Hospital falls: a persistent problem.

During a 22-month period in 1981-82, 250 falls were recorded at a 152-bed acute care specialty hospital in a United States metropolitan area. Rates were highest for patients age 65 years and older and for patients admitted with mental disorders. Patients who had fallen once had a subsequent fall rate of 91.7 per 1,000 patients compared to an overall rate of 18.7 for first falls. Half the falls occurred in or enroute to the private bathroom attached to each room. Only three falls resulted in injury sufficient to prolong hospital stay.

Accidents↗
PubMed1985

Ventilatory response to intravenous methionine enkephalin in awake dogs.

In conscious, microfilaria-free, adult mongrel dogs, i.v. bolus administration of methionine enkephalin (Met5-ENK) produced a transient elevation of both inspiratory minute ventilation (VI) and heart rate (HR). Both VI and HR increased progressively with increasing doses of Met5-ENK over the range of 6 to 18 micrograms/kg, thereafter plateauing at doses up to 36 micrograms/kg. Maximum changes in VI and HR occurred within 30 to 45 sec after injection, both variables returning to control levels in approximately 2 min. In four out of five dogs, mean inspiratory flow (tidal volume/inspiratory time), and consequently, tidal volume, accounted for this enkephalin-mediated increase in ventilation. In one of the dogs, respiratory rate, rather than tidal volume, increased after Met5-ENK. This change in respiratory rate was due to an increase in "effective timing" of the respiratory cycle, the latter defined as the ratio of inspiratory time to total respiratory time. Despite significant changes in VI and HR, neither end tidal oxygen nor carbon dioxide levels were significantly different from control after i.v. injections of Met5-ENK. Pretreatment with naltrexone methylbromide, a quaternary opiate antagonist that does not cross the blood-brain barrier, abolished all enkephalin-induced changes in VI and HR, thus suggesting that systemic enkephalins modulate ventilation via opiate receptors outside the blood-brain barrier. Activation of these receptors produce an increase in both cardiovascular and respiratory activity, as one might expect during stress conditions. These data further support a potential role for peripheral enkephalins as excitatory stress hormones.

Animals↗
PubMed1984

A continuous wave technique for the measurement of the elastic properties of cortical bone.

A continuous wave technique is described for measuring the nine independent orthotropic elastic coefficients from a single cubic specimen. The side dimensions of this cubic specimen are on the order of 5 mm. Because of the small size of the specimen, the spatial resolution of material inhomogeneity using this technique is quite good. Although it is possible to apply this technique to any elastic material such as woods or metals, the elastic properties of human and canine cortical femora are presented here. The orthotropic elastic coefficients and the variation of these coefficients are presented as a function of anatomical position.

Animals↗
PubMed1984

Potential role of parathyroid hormone as an inhibitor of erythropoiesis in the anemia of renal failure.

Patients with varying degrees of renal insufficiency and patients with end-stage renal disease receiving continuous ambulatory peritoneal dialysis or regular hemodialysis therapy were studied to assess the independent relationship between serum parathyroid hormone concentration, and both severity of anemia and degree of serum inhibition of erythropoiesis. In patients with renal insufficiency not receiving dialysis, a significant curvilinear relationship between serum parathyroid hormone and creatinine concentrations was present (r = 65, p less than 0.001). Serum parathyroid hormone (by radioimmunoassay) also correlated with hematocrit level (r = -0.54, p less than 0.001) and degree of serum inhibition of in vitro erythroid progenitor cell growth in fetal mouse liver cultures (r = -0.45, p less than 0.001). However, multiple linear regression analysis revealed that after controlling for the effect of creatinine, m-parathyroid hormone is no longer a significant predictor of hematocrit level or erythroid progenitor cell growth. On the other hand, when a restricted population of patients with creatinine values between 1 and 4 mg/dl was analyzed separately, controlling for the effect of creatinine, there was still a significant correlation between hematocrit level and m-parathyroid hormone, but no such relationship was seen when participants with parathyroid hormone levels of less than or equal to 1000 pg/ml were analyzed. No significant correlation was seen between hematocrit level or inhibition of erythroid colony growth and serum parathyroid hormone concentrations in patients receiving either regular hemodialysis or continuous ambulatory peritoneal dialysis. In 13 patients given regular hemodialysis studied before and after parathyroidectomy, there was no significant change in serum erythropoietin (by radioimmunoassay) or serum inhibition of erythropoiesis, although hematocrit levels increased in six of the 13 patients. The 1-34 human parathyroid hormone, 1-84 bovine parathyroid hormone, and 1,25-dihydroxycholecalciferol had no effect on in vitro erythroid burst-forming unit growth. Parathyroid hormone (8 mu/ml) inhibited and 1,25-dihydroxycholecalciferol (4.0 ng/ml) stimulated erythroid colony-forming unit growth only in the absence of exogenous erythropoietin in culture. In summary, it was not possible to demonstrate a significant relationship between serum parathyroid hormone levels and anemia or inhibition of erythropoiesis in patients with uremia either before starting dialysis or after receiving long-term dialysis treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1983

Hypolipidemic effects of clofibrate and selected chroman analogs in fasted rats: II. High sucrose-fed animals.

The hypolipidemic properties of ethyl 6-chlorochroman-2-carboxylate (II), 6-phenylchroman-2-carboxylate (III) and 6-cyclohexylchroman-2-carboxylate (IV) were compared to clofibrate (I) in sucrose-fed fasted male Sprague-Dawley rats. All compounds were administered at doses of 0.2 and 0.4 mmol/kg, orally, twice daily for 7 consecutive days. In this model, II was a more effective hypocholesterolemic drug than clofibrate, whereas III and IV were inactive. Chlorochroman II, like clofibrate, decreased serum alpha-lipoprotein cholesterol and pre-beta-lipoprotein triglyceride concentrations and concomitantly increased serum beta-lipoprotein triglyceride concentrations. In clofibrate-treated rats, serum free cholesterol concentrations increased concurrent with a reduction in serum lecithin: cholesterol acyltransferase activity, but no such correlation was observed for II. Only II lowered liver cholesterol levels and increased liver triglyceride levels. No consistent inhibition of liver microsomal 3-hydroxy-3-methylglutaryl-CoA reductase activity was observed with these analogs. The observed changes in triglyceride and cholesterol concentrations among serum lipoproteins were of a greater magnitude after chlorochroman II and clofibrate administration to sucrose-fed rats than in our previous studies using chow-fed fasted rats. These data suggest that chloro-substitution at the 6-position of the phenylchroman ring is important for hypolipidemic activity of these cyclic clofibrate analogs.

Animals↗
PubMed1983

Disordered salivary immunoglobulin secretion and sodium transport in human chronic graft-versus-host disease.

Whole saliva samples and lip biopsies were collected from 12 allogeneic bone marrow transplant recipients who developed extensive chronic graft-versus-host disease (GVHD) and from 10 healthy allogeneic and syngeneic recipients without GVHD. Six of ten biopsies from patients with chronic GVHD had lichenoid stomatitis or sialadenitis, or both, with sialodochitis. Seven of nine biopsies from patients free of chronic GVHD were entirely normal, and two had either mild glandular or mucosal changes. Salivary gland involvement in chronic GVHD was associated with decreased or absent levels of salivary IgA and inorganic phosphate, decreased salivary flow rates, and increased concentrations of salivary sodium, albumin, and IgG. The most striking abnormalities were found in patients with histologic evidence of sialadenitis. In contrast, marrow transplant recipients without chronic GVHD had normal salivary immunoglobulin and electrolyte levels. Secretory IgA deficiency may contribute to the frequent sinobronchial infections observed in patients with chronic GVHD.

Adolescent↗
PubMed1981

Whole saliva albumin as an indicator of stomatitis in cancer therapy patients.

Albumin concentrations were measured in whole and parotid saliva samples collected from patients who were undergoing various cancer treatment protocols and had a high incidence of stomatitis. Oral examinations were made at the time of saliva collection and the degree of stomatitis evaluated. Elevations of whole saliva albumin concentrations were observed in 11 stomatitis incidents. No increases were observed in parotid saliva. The salivary albumin increases always preceded and often occurred in the absence of stomatitis, suggesting that the whole saliva albumin level may be a useful measure and predictor of this condition. If so, monitoring of this parameter could be useful in establishing treatment schedules for chemotherapy protocols that have stomatitis as the limiting factor in treatment.

Adolescent↗
PubMed1981

Hypolipidemic effects of clofibrate and selected chroman analogs in fasted rats: I. Chow-fed animals.

The hypolipidemic properties of ethyl 6-chlorochroman-2-carboxylate (II), ethyl 6-phenylchroman-2-carboxylate (III) and ethyl 6-cyclohexylchroman-2-carboxylate (IV) were compared to clofibrate (I) in fasted normolipidemic rats. The chroman analog II, like its parent compound, clofibrate, reduced serum and alpha-lipoprotein cholesterol concentrations. Although analog III had no effect on serum cholesterol, it caused a slight elevation of alpha-lipoprotein cholesterol concentration. Serum free cholesterol was increased and LCAT activity was reduced in clofibrate-treated rats. The hypolipidemic agents had no consistent effect on liver lipid concentrations and liver microsomal HMG-CoA reductase activity. In addition, we have shown that drug efficacies varied directly with seasonal variations in serum lipid concentrations.

Animals↗
PubMed1981

Parotid gland pathophysiology after mixed gamma and neutron irradiation of cancer patients.

Electrolyte and protein concentrations were measured in parotid saliva samples obtained from patients receiving localized, fractionated, neutron and gamma irradiation for the treatment of cancer. Salivary sodium chloride concentration increased transiently but then usually decreased to preirradiation values after 2 weeks of therapy. There were concurrent decreases in salivary flow rate, pH, and bicarbonate concentration. The decreases in sodium chloride concentration and flow rate are inconsistent with a previously suggested, irradiation-induced ductal sodium resorption defect. The findings contribute toward understanding how salivary gland physiology is altered in irradiation injury.

Aged↗