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Biomedical subjects

J C Rice

Publications and source records attributed to J C Rice.

At least 73 records · Page 4Linked to original sources
PubMed1989

College students' knowledge and health beliefs about AIDS: implications for education and prevention.

A questionnaire designed to measure the application of the dimensions of the Health Belief Model (HBM) to AIDS prevention and to practicing safer sex was administered to 139 undergraduates aged 22 years and under. Students generally had good knowledge about the facts of AIDS, which was consistent with other studies. We found an important difference between students' beliefs about practicing safer sex to prevent AIDS depending on whether their level of knowledge was high or low. The HBM posits that all of its dimensions must be present in order for belief to be followed by action. However, students with low knowledge indicated that the perceived barriers to practicing safer sex were higher than did students with high knowledge about AIDS. These results suggest that special efforts need to be made to teach students with low knowledge more about AIDS and that the barriers to safer sex can and should be overcome. There were no differences between students known to be sexually active compared with those who may or may not have been sexually active. One explanation was a possibly high number of students in the group identified as "perhaps sexually active" who actually were sexually active. Similarly, there were no differences between college students who did or did not know someone with AIDS, but this may have been due to the small number of students who did know such a person. Students' preferences for the format and methodology of AIDS education also were presented. In general, the students preferred small-group discussions and formats such as movies or panel discussions where they could remain "anonymous."(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1989

Penetrating injuries to the colon: analysis by anatomic region of injury.

The preferred method for the treatment of penetrating injuries to the colon remains a source of controversy. In our retrospective review of 65 patients with penetrating colon injuries, 33 patients were managed by colostomy formation, 30 were treated by primary repair, and two had exteriorized repair with early return to the abdominal cavity (drop back). The anatomic location of injury was ascending colon in 19 (29%), transverse colon in 20 (31%), descending colon in 22 (34%), and multiple sites in four (6%). The average penetrating abdominal trauma index (PATI) was 24 (ascending colon injuries, 23; transverse colon, 26; descending colon, 24; and multiple colon sites, 28). Overall septic morbidity was 15/65 (23%). Colostomy closure was later done in 32/33 (97%), with a morbidity of 7/32 (22%). The mean length of hospital stay for primary repair was ten days and for colostomy (including both required hospital stays), 26 days (P less than .05). These data suggest that primary repair is as safe as colostomy formation for the management of penetrating colon injuries, regardless of anatomic site of injury.

Adult↗
PubMed1989

Erythropoietin production in exhypoxic polycythemic mice.

Our present study was undertaken to determine the serum erythropoietin concentration (radioimmunoassay), hematocrit, red cell mass, and body weight of mice exposed to hypoxia in a hypobaric chamber (0.42 atm, 22 h/day) for 14 days and during the 10 posthypoxic days at ambient pressure to clarify the correlation of the red cell mass and erythropoietin production during hypoxia. The mean serum erythropoietin titer was 326.23 +/- 77.04 mU/ml after 2 days, reached the highest level after 3 days (452.2 +/- 114.5 mU/ml), then gradually declined to a level of 36.5 +/- 11.4 mU/ml after 14 days of hypoxia, and was undetectable during the 10-day posthypoxic period. The hematocrit values were significantly increased from 41.09 +/- 0.50% at day 0 to 51.65 +/- 1.08% after 3 days and to 72.20 +/- 1.53% after 14 days of hypoxia. The red cell mass (calculated from initial body weight) increased from 3.24 +/- 0.1 ml/100 g at day 0 to 7.32 +/- 0.46 ml/100 g after 14 days of hypoxia and declined to 6.66 +/- 0.53 ml/100 g at the end of the 10-day posthypoxic period. The mice lost weight while they were in the hypobaric chamber and showed a significant increase in body weight during the 10-day posthypoxic period. These studies support the concept that chronic intermittent hypoxia causes an early increase, followed by a rapid decline, in erythropoietin production, which is correlated with the gradual increase in red cell mass.

Animals↗
PubMed1989

Lower limb embolus: a near-lethal disease after age 75 years.

Because it has been suggested that embolectomy increases morbidity and mortality, we reviewed our experience with lower-extremity embolectomy in an elderly high-risk population. Of 153 consecutive patient records reviewed, 69 were sufficiently complete for analysis. Of these patients, 45 were men with a mean age of 80.7 years (range, 75 to 91 years); 24 were women with a mean age of 76.9 years (range, 75 to 81 years). Records were reviewed for patient age, sex, race, acute myocardial infarction or atrial fibrillation upon admission, history of smoking, diabetes, and cardiac disease (acute and chronic), admission blood pressure, role of postoperative echocardiography, and New York Heart Association classification (NYHA class). All patients were hemodynamically stable at the time of operation. Forty-two of the 69 patients had a history of smoking, nine were diabetic, and 48 (33 men and 15 women) had hypertension (blood pressure greater than 140/90 mm Hg) on admission. Twelve deaths occurred within the perioperative period. Nine patients had an acute myocardial infarction and 12 had arrhythmias on admission. Thirty patients (15 men and 15 women) were in NYHA class III. A total of 30 patients had died by six months postoperatively, 27 of cardiovascular causes. The perioperative mortality was 12/69 (17%), and long-term mortality was 30/69 (43%). Simultaneous embolus and myocardial infarction was associated with 100% mortality for the patients surviving the operation; 15 patients required another operation for amputation (nine above-knee and six below-knee).

Age Factors↗
PubMed1989

Penetrating injury to the carotid artery. A reappraisal of management.

Penetrating trauma remains the most common cause of cervical carotid artery injury. Controversy persists regarding proper management of these injuries, especially in the presence of a neurologic deficit. Recent experience with 24 patients over a 5-year period is reviewed. In patients with preoperative neurologic deficits, neither repair nor ligation of the injured vessel altered outcome. Outcome correlated only with preoperative neurologic status. All patients without preoperative neurologic deficits should have repair attempted when technically feasible. Although controversial, this study supports carotid artery repair except in comatose patients who have profound neurologic deficits.

Adult↗
PubMed1988

On the dependence of the elasticity and strength of cancellous bone on apparent density.

This paper presents a statistical analysis of the pooled data from a number of previous experiments concerning the dependence of the Young's moduli and strength of cancellous bone tissue upon apparent density. The results show that both the Young's moduli and the strength are proportional to the square of apparent density of the tissue and are therefore proportional to one another. It is shown that the coefficient of proportionality is different for human and bovine tissue. It is concluded that the suggestion of Wolff (Das Gesetz der Transformation der Knochen, Hirschwald, Berlin, 1892) that compact bone tissue is simply more dense cancellous bone tissue is not an accurate statement when only the mechanical properties of these two tissues are considered. It is noted that estimates for the elastic modulus of the individual trabecula of human cancellous bone vary from 1 to 20 GPa and it is suggested that this question needs further study.

Biomechanical Phenomena↗
PubMed1988

Measurement of impotence by laser Doppler flowmetry and conventional methodology.

The problem of vasculogenic impotence was evaluated by laser Doppler flowmetry with the LD5000 capillary perfusion monitor to determine cutaneous penile blood flow in 25 men defined previously as impotent by Doppler ultrasound with penile brachial ratios of 0.63 +/- 0.14. Erotic visual stimulation for 1, 2 and 4 minutes did not statistically change the cutaneous flow as measured by laser Doppler flowmetry from its baseline of 20 mv. The dynamics of skin microcirculation in the penis may reflect changes in the deeper vessels and represent an alternate, dependable method to evaluate capillary perfusion.

Adult↗
PubMed1988

Assessment of the use of transfusion therapy perioperatively in patients with sickle cell hemoglobinopathies.

During the period of 1978 to 1986, 66 patients (31 men, 35 women) with a mean age of 28.4 years and various sickle cell hemoglobinopathies underwent 82 surgical procedures; 28 were emergencies. Fifty of the 66 patients had HbSS, 13/66 had HbSC, and 3/66 had HbS-thalassemia. All 66 patients received transfusions, although not for all procedures. In 48 patients, transfusion therapy was only administered preoperatively. Simple transfusions (1 to 10 units) were administered in 31 of 48 procedures. Exchange transfusions (1 to 6 units) were performed in nine of 48 procedures. Preoperative hematocrit ranged from 7.0% to 54.2%; of those receiving transfusions the hematocrit ranged from 22.6% to 53.7%. Intraoperative transfusions (1 to 10 units) were performed in 14 of 82 procedures; postoperative transfusions (1 to 6 units) were performed in 13 of 82 procedures. No advantage was noted in preoperative exchange transfusion as measured by a decrease in postoperative complications; a slight increase was seen in atelectasis in this group of patients with preoperative transfusions. An increase was reported in the complication rate of patients with an hematocrit of less than 30%. The type of transfusion (preoperative, intraoperative, or postoperative) administered did not appear to be related to postoperative morbidity rates. The complication rate for simple transfusions was 51.6% and for multiple transfusions, 55.6%. HbSS hemoglobinopathy had the higher complication rate. The hepatitis B surface antigen was demonstrated in four of 66 (6.1%) patients; ten of 66 (15.2%) developed alloantibodies. The benefits of transfusion therapy should be judged according to clinical needs; not all sickle cell patients need exchange or preoperative transfusion.

Adult↗
PubMed1988

Tortuosity of the right common carotid artery simulating aneurysm.

Among the problems that confront the vascular surgeon, a pulsatile, right-sided neck mass requires a careful and logical evaluation. It has long been known that tortuosity of the right common carotid artery, frequently associated with advanced hypertension, can physically mimic a right carotid aneurysm. The question, then, is whether carotid angiography, with a higher attendant risk of morbidity and mortality, is preferable to less invasive diagnostic modalities such as computerized tomography (CT) and ultrasonography for initial evaluation. In our study, 31 consecutive patients with a pulsatile right neck mass, indistinguishable on physical examination from a carotid aneurysm, were evaluated using CT scan of the neck and either radionuclide scan or angiography. In all of the patients, the masses were confirmed to be tortuous right common carotid arteries and not aneurysms. Because a kinked carotid artery simulating an aneurysm occurs so frequently, noninvasive diagnostic techniques, such as CT and ultrasonography, should precede angiography. We also discuss demographic characteristics commonly associated with tortuosity of the right common carotid artery.

Aged↗
PubMed1988

Sequelae of limited amputation.

Ninety patients underwent toe amputations because of vascular disease; 21% required higher amputation and 21% healed without further surgery (i.e., revascularization). Of 60 patients who required bypass surgery, 52 underwent successful first amputations and eight required higher amputations. No difference was seen between diabetic and nondiabetic patients in eventual limb salvage; however, men fared better than women. Without bypass surgery, 11 of 30 patients required a higher level of amputation. No patient's toe amputation site healed with an ankle-to-brachial index of less than 0.35. The judicious use of toe amputation remains an important tool in the surgeon's quest for limb salvage.

Adult↗
PubMed1988

Below-knee physiologic cryoanesthesia in the critically ill patient.

Controversy has surrounded the role of local hypothermia as a preoperative treatment in amputations of the lower extremity. A study was undertaken to determine the effectiveness of amputation under cryoanesthesia in decreasing postoperative morbidity and mortality in below-knee (BK) amputations. Of 154 BK amputations, only 91 with unreconstructable vascular disease, gangrene, or both, were included in this study. Group I consisted of 48 patients (mean age 63.9 years) who had undergone a routine BK amputation; group II consisted of 43 patients (mean age 65.7 years) who were acutely ill and too unstable to undergo a major surgical procedure. Group II patients were treated by amputation while under cryoanesthesia before any definitive operative intervention. The patients in group II were significantly (p less than 0.05) more ill preoperatively than those in group I. Group II patients had a higher prevalence of previous myocardial infarction, previous stroke, diabetes mellitus, osteomyelitis, and wet gangrene. Seventy percent of the patients in group II had three or more risk factors vs. 46% in group I. Early postoperative mortality rates did not differ significantly between groups (group I, 8%; group II, 9%); the average length of hospital stay for group I patients was 24.2 days compared with 17.7 days in group II. Group II patients sustained slightly more postoperative complications. Amputation under cryoanesthesia appears to be of value in reducing postoperative morbidity and mortality and length of hospital stay in the acutely ill patient with unreconstructable vascular disease, gangrene, or both.

Aged↗
PubMed1988

Pharmacokinetics of erythropoietin in intact and anephric dogs.

The present studies were performed to determine the pharmacokinetic parameters of erythropoietin in intact and anephric dogs by use of unlabeled crude native erythropoietin (nEp) and iodine 125-labeled purified recombinant erythropoietin (rEp) given by intravenous infusion for 15 minutes. Sephadex G-75 gel filtration was used to confirm that the 125I-rEp molecule remained iodinated in dog plasma during the 24-hour period of these studies. The plasma disappearance of erythropoietin conformed to a biexponential equation for both nEp and 125I-rEp, with the central compartment being larger than the peripheral compartment. The mean distribution half-life of 75.3 +/- 21.2 minutes for nEp was significantly (p less than 0.05) longer than that of 125I-rEp (23.7 +/- 5.0 minutes) in intact dogs. The intercompartmental clearance (CIic) for nEp (0.018 +/- 0.006 L/kg/hr) was significantly smaller than that of 125I-rEp (0.068 +/- 0.018 L/kg/hr) in intact dogs (p less than 0.05). There were no significant differences in apparent volume of distribution, elimination half-life, and elimination clearance (CIe) for nEp and rEp in intact dogs. The mean elimination half-life for 125I-rEp in intact dogs (9.0 +/- 0.6 hours) and anephric dogs (13.8 +/- 1.4 hours) was significantly different (p less than 0.05). The CIe for 125I-rEp in anephric dogs (0.008 +/- 0.001 L/kg/hr) was significantly (p less than 0.05) smaller than that of 125I-rEp in intact dogs (0.011 +/- 0.001 L/kg/hr). There were no significant differences in apparent volume of distribution, distribution half-life, and CIic for 125I-rEp in intact and anephric dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Problems in placement of the Greenfield inferior vena cava filter.

Placement of an intracaval device is the treatment of choice for failure of, or contraindication to, anticoagulation therapy. A retrospective study of 111 patients from 1980 to 1986 was undertaken to identify the incidence and degree of related complications or problems regarding placement of the device. Ninety seven of 111 (87.4%) patients had no complications or problems in placement; 14/111 (12.6%) patients did have problems. Of the latter group, mechanical problems included eccentric filter placement, insertional difficulty, problems in filter carrier removal, premature discharge, and misplacement. A total of four patients required a second filter. A single instance of worsening renal insufficiency was noted. Of the total group (ages 24 to 97 [means = 62.4] years), other medical problems including diabetes, smoking, malignancy, sepsis, hypertension, and alcoholism had no influence on the complications or problems. The Greenfield filter remains the method of choice for the listed indications; however, an awareness of potential problems may lessen the technical complications. The operative problems did not adversely impact hospital morbidity or cost.

Adult↗
PubMed1987

Metabolism of the mutagen MeIQx in vivo: metabolite screening by liquid chromatography-thermospray mass spectrometry.

2-Amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx) is a potent mutagen found in cooked food. MeIQx and its isotopically labelled (13C, 15N2 and 14C) analogues were synthesised and used for metabolic studies in vivo. An equimolar mixture of MeIQx and its 13C, 15N2 stable isotope labelled analogue (containing tracer amounts of 14C-MeIQx) was given intraperitoneally to mice. Some 67% of the radioactivity was eliminated in urine and faeces within 24h. Four radiolabelled species were observed when urine was analysed by HPLC, corresponding to unchanged MeIQx and three more polar metabolites. Urine was analysed directly by HPLC-thermospray mass spectrometry. Four signals were observed containing the characteristic 1:1 isotopic doublet, corresponding to unchanged MeIQx, an MeIQx glucuronide, and two uncharacterized metabolites.

Animals↗
PubMed1987

Central to peripheral sound propagation in excised lung.

The time it takes audible sound to travel from the trachea to the pleura in five intact, excised horse lungs and one dog lung inflated with several gases was measured. Regression estimates of sound speed at total lung capacity (TLC) using straight line distance from the carina to the pleura are: helium, 775 +/- 60.5 m/s (means +/- 95% confidence limits); air, 282 +/- 23.5; carbon dioxide, 219 +/- 25.5; sulfur hexafluoride, 142 +/- 43.5. With the exception of sulfur hexafluoride, these speeds are 15%-20% less than the free-field speed of sound in each gas. Total airway length did not predict time delay any better or worse than straight line distance, but the high correlation between these two predictors (r = 0.94) prevents showing either to be the more predictive. In one lung, airway length was partitioned according to airway diameter. A regression using partitioned airway lengths significantly improved time delay prediction (p less than 0.001) over an unpartitioned model. Sound speed in the trachea equals free-field sound speed. Sound speed in air-filled airways 1 to 25 mm in diameter equals 268 +/- 44 m/s. We conclude that the first sound to reach the surface travels in the airways for at least 90% of the distance, spending at least 87% of the total travel time there.

Acoustics↗
PubMed1987

Acute and short-term effects of clonidine in heart failure.

The authors performed a randomized, double-blind, placebo-controlled trial to assess the tolerance and effects of chronic oral clonidine administration on the clinical status, exercise tolerance, and ventricular function of 10 male patients with chronic heart failure. Patients were given either oral clonidine (400 micrograms/day) or matching placebo for twelve weeks and then tapered off medication over a two-week period. Results are summarized as follows: Profiles over time between groups were significantly different for resting heart rate (p = 0.0005), were different for arterial pressure (p = 0.04), were different for left ventricular ejection fraction (p less than 0.006), and were different for mean accumulated workload (p = 0.076). Exercise double product at 25 watts changed little in three patients and showed a decrease in 2 patients following six weeks of oral clonidine; after twelve weeks, it decreased in three patients, increased in 1, and changed little in another. After washout, double product returned toward baseline values. In the placebo groups, double product showed little change. Resting of the heart by decreasing heart rate, systemic arterial blood pressure, and venous tone are thought by the authors to be major contributing factors to the observed beneficial effect of chronic oral clonidine in chronic heart failure.

Administration, Oral↗
PubMed1987

Effect of commercially available pantyhose on venous return in the lower extremity.

Although compression stockings have long been recognized as a physiologically significant tool for the promotion of venous return from the lower extremity, the role of nonprescription, commercially available support hose has not been assessed in this regard. The present study involved 100 consecutive women with no known prior history of vascular disease, who responded to an advertisement for free evaluation of the venous status of their legs. The subjects, all of whom wore commercial support hose routinely, were screened for the presence of venous disease by means of Doppler ultrasonography, phleborheography, and a detailed history focusing on risk factors and unrecognized symptoms of venous disease. Photoplethysmography (PPG) was then used to evaluate the efficiency of venous return from the lower extremity with and without the support hose in place. Worsening of PPG results occurred in 43% of the women with commercial stockings in place, whereas 23% improved and 34% showed no change. Women 50 years of age and older had a somewhat higher tendency toward poorer PPG results while wearing the support hose. Furthermore, measurements in women who showed evidence of venous disease by an abnormality in one or more of the screening tests were significantly different from the overall group (p = 0.025): 61% exhibited worsening of PPG results when wearing stockings, only 14% showed improvement, and 25% were unchanged. These results suggest that the use of a commercial support hose may be particularly deleterious to older women and is contraindicated in those with evidence of venous disease in the lower extremity.

Adult↗