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Biomedical subjects

S A Gall

Publications and source records attributed to S A Gall.

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

Mechanical determinants of myocardial oxygen consumption in conscious dogs.

A new practical descriptor of metabolic to mechanical myocardial energy transfer (MET), termed the virtual work model, was evaluated in 32 conscious dogs and in 8 isolated canine hearts. An index of total mechanical energy expenditure (TME) was calculated as the sum of external energy (stroke work) and an internal energy index of heat (left ventricular end-diastolic volume times left ventricular mean ejection pressure). Physiological comparison of TME (x-axis) and myocardial oxygen consumption (MVO2; y-axis) yielded highly linear MET relationships (mean r = 0.93 +/- 0.07), with an average slope of 0.86 +/- 0.39 (SD) and a y-intercept of 9.1 +/- 6.4 mW/ml myocardium. The linear MVO2-TME relationship did not vary under steady-state vs. dynamic vena caval occlusion, increased heart rate, increased afterload, or increased inotropic state with calcium infusion. Compared with five other indexes of myocardial energetics, the virtual work model of MET was the most linear, the most practical in not requiring determination of the end-systolic pressure-volume relationship, and the most accurate predictor of MVO2 under normal and altered hemodynamic conditions.

Animals↗
PubMed1995

Revascularization of the internal mammary artery after coronary artery bypass grafting.

Symptomatic anterior myocardial ischemia as a result of stenosis at the origin of the left internal mammary artery developed in a patient who underwent prior coronary artery bypass grafting using the left internal mammary artery as a conduit. Successful revascularization of the left anterior descending coronary artery was achieved using a reversed saphenous vein bypass graft from the left common carotid artery to the proximal internal mammary artery. This approach provided myocardial revascularization and avoided reoperative median sternotomy.

Aged↗
PubMed1995

Rupture of the external iliac artery during pregnancy: a case of type IV Ehlers-Danlos syndrome.

Ehlers-Danlos Syndrome is a group of connective tissue disorders involving defects in collagen synthesis. Ten different types have been described. The most lethal of these is type IV, with up to 25% maternal mortality described. The defect in type III collagen can lead to rupture of arteries, bowel, or uterus. We present a maternal mortality that occurred in a patient not previously known to have Ehlers-Danlos syndrome. She presented at 29 weeks gestational age with a ruptured external iliac artery. Further complications, including jejunal rupture and aortic disruption ultimately led to her demise. Postmortem examination ultimately confirmed the diagnosis of type IV Ehlers-Danlos syndrome. Although type IV Ehlers-Danlos syndrome is rare, it carries a high risk for maternal morbidity and mortality. Therefore, it is important to be aware of the diagnosis prior to pregnancy and to have a high index of suspicion for arterial or viscus perforation in the face of acute abdominal findings.

Adult↗
PubMed1994

Measurement of left ventricular volume in normal and volume-overloaded canine hearts.

Serial studies of adaptation to aortic regurgitation (AR) were undertaken to determine whether sonomicrometry and echocardiography could be combined to measure changes in left ventricular (LV) cavitary volume (Vlv) and wall mass using the geometric formula [Vlv = K pi b2 alpha--wall volume], where K is a constant depending on the geometric model and a and be are epicardial major- and minor-axis diameters, respectively. Postmortem studies were performed in six normal dogs and in nine with AR; ultrasonic ventricular dimensions were measured as Vlv was varied with an intracavitary balloon. Three models were tested: 1) ellipsoid (model I; K = 1/6), 2) cylinder-ellipsoid (model II; K = 5/24), and 3) cylinder (model III; K = 1/4). The slope of the relationship between calculated Vlv and balloon volume varied between models (I, 0.71 +/- 0.11; II, 0.89 +/- 0.14; III, 1.07 +/- 0.17), and empiric determination of K to produce a slope of 1.0 resulted in a value of 0.26 +/- 0.04, not significantly different from the cylindrical model. Serial measurements of LV dimensions in 10 chronically instrumented conscious dogs revealed no significant change in end-diastolic or end-ejection LV shape after up to 16 wk of AR. Sonomicrometry and echocardiography can be integrated using a cylindrical geometric model to accurately estimate changes in end-diastolic or end-ejection Vlv during chronic volume overload.

Animals↗
PubMed1994

Effects of cardiac glycosides on myocardial function and energetics in conscious dogs.

The physiological effects of intravenous ouabain on left ventricular (LV) systolic function and metabolic-to-mechanical energy transfer were examined in eight conscious dogs. LV pressure and volume were measured using micromanometers and ultrasonic dimension transducers during transient vena caval occlusions under control conditions and after increasing doses of ouabain. Doppler coronary flow and coronary sinus O2 saturations were used to determine arterial-to-coronary sinus O2 content difference and thereby to calculate LV O2 consumption; total mechanical energy was computed as the sum of LV stroke work and the product of end-diastolic volume and LV mean ejection pressure, neglecting LV unstressed cavitary volume. The slope (10(4) erg/ml) of the stroke work vs. end-diastolic volume relationship increased progressively with rising doses of ouabain from 7.0 +/- 1.6 at control to 9.6 +/- 1.7 after ouabain 0.75 mg (P = 0.0002). Regression analysis of LV O2 consumption (mW/cm3) vs. total mechanical energy (mW/cm3) yielded a linear relationship that did not change with 0.75 mg of ouabain (P > 0.4). These data indicate that ouabain possesses a significant positive inotropic effect on the intact left ventricle without a change in energy transfer efficiency or O2 wasting.

Animals↗
PubMed1993

Recovery of myocardial function after repetitive episodes of reversible ischemia.

The question of whether recovery of regional myocardial function after repetitive, reversible ischemia differs from recovery after a single episode of myocardial ischemia remains controversial. Therefore, eight conscious dogs were instrumented with ultrasonic dimension transducers and left ventricular micromanometers. Each animal underwent (in random sequence, 72 h apart) a single 15-min left anterior descending coronary arterial (LAD) occlusion and two 15-min LAD occlusions separated by 1 h of reperfusion. The preload recruitable work area (PRWA; the area beneath the regional stroke work vs. end-diastolic length relationship) quantified regional myocardial performance. Repetitive ischemia significantly delayed recovery of PRWA over the first 24 h (P < 0.05). Although postischemic myocardial creep resolved rapidly after single occlusion, double occlusion prevented recovery of creep during the first 4 h of reperfusion. The recovery time course of PRWA paralleled the resolution of myocardial creep, suggesting that creep contributed significantly to delayed functional recovery and that myocardial "stunning" after repetitive ischemia may result in part from interaction between postischemic diastolic properties and systolic dysfunction.

Animals↗
PubMed1993

Myocardial infarction in the third trimester of pregnancy secondary to an aortic valve thrombus.

BACKGROUND: Myocardial infarction during pregnancy is rare, at an estimated one case per 10,000 women delivered. The overall mortality rate is 28% and is even higher in the second and third trimesters. We report a myocardial infarction secondary to a thrombus that developed on an artificial aortic valve in a 25-year-old woman at 26 weeks' gestation. CASE: The patient, gravida 6, para 3-0-2-3, presented with an acute myocardial infarction despite antepartum anticoagulant therapy with heparin. During her hospitalization, she experienced a second ischemic event, preterm labor, and a small upper gastrointestinal hemorrhage. Nitroglycerin, sublingual nifedipine, and heparin were used to stabilize her cardiac problems, and her uterine contractions were inhibited with tocolytic agents. At 35 weeks' gestation, she underwent an uncomplicated vaginal delivery of a 2608-g viable male infant. CONCLUSION: Pregnancy complicated by myocardial infarction due to a valve thrombosis in the third trimester can be managed with careful attention to controlling the cardiac symptoms and preventing premature delivery.

Adult↗
PubMed1991

Quantitative and qualitative platelet abnormalities during pregnancy.

In a 1-year period, 15 of 4048 pregnant women were found to have thrombocytopenia during their first prenatal visit. Their qualitative and quantitative platelet abnormalities were followed up prospectively for 1 to 6 months post partum. Platelet counts returned to normal in 14 of 15 patients 4 to 6 weeks post partum. von Willebrand factor antigen and ristocetin cofactor activity were low in three of 15 patients 4 to 6 weeks post partum, but had been normal during the antepartum period. Two of these three patients had prolonged bleeding times ante partum and post partum. All three patients subsequently were found to have mild type I von Willebrand disease. Six patients had detectable platelet antibodies. Neonatal thrombocytopenia was found in one term infant of a patient with mild thrombocytopenia and negative platelet antibodies. This study suggests that mild, transient, isolated thrombocytopenia can occur in an otherwise normal pregnancy and its incidence may be lower than previously reported. Extensive testing is not indicated unless there is an associated prolonged bleeding time. The possibility of von Willebrand disease or a qualitative platelet disorder should be considered.

Adolescent↗
PubMed1991

Therapy of persistent human papillomavirus disease with two different interferon species.

Consensus interferon and interferon alfa-2a were used to treat patients with persistent human papillomavirus disease. Thirty-one patients were treated with either consensus interferon or a placebo (25 received active drug and 6 received placebo), and 24 patients were treated with interferon alfa-2a. Of the 25 patients who received consensus interferon, 19 (76%) showed either complete or partial clearing of condyloma 10 and 16 weeks after initiation of therapy; in 22 of the 24 patients (91%) who received interferon alfa-2a, clearing was demonstrated after a similar time period. Thirty of 34 patients who had no response or a partial response requested additional therapy, and 20 of these patients treated with adjunctive therapy had a complete response. The results of this study support the efficacy of both interferons in the treatment of overt condyloma acuminatum and suggest that interferon enhances subsequent adjunctive therapy.

Adolescent↗
PubMed1990

Ellipsoidal shell subtraction model of right ventricular volume. Comparison with regional free wall dimensions as indexes of right ventricular function.

Pulse-transit sonomicrometry was used to measure the base-apex (a), anteroposterior (b), and septal-free wall (c) diameters of the left ventricle and the septal-free wall diameter of the right ventricle (d) in eight excised and three isolated, pump-perfused canine heart preparations, as well as in nine conscious dogs. In the three perfused hearts and in four of the excised hearts, right ventricular free wall regional segment lengths and segment area also were assessed. Biventricular volumes were measured directly with intracavitary balloons in all isolated hearts. When left ventricular balloon volume was held constant, relations between right ventricular free wall dimensions and right ventricular balloon volume were highly linear. With increments in left ventricular volume, however, these relations remained linear but shifted progressively upward, indicating an independent relation between right ventricular free wall dimensions and left ventricular cavitary volume. An ellipsoidal shell subtraction model (pi/6.abd minus right ventricular free wall volume) was developed to estimate right ventricular cavitary volume from cardiac dimensions. With this method, a highly linear relation was observed between calculated right ventricular volume and right ventricular balloon volume (mean r = 0.99 +/- 0.01). Moreover, this relation appeared to be independent of changes in left ventricular balloon volume. With the shell subtraction model, dynamic right ventricular volume was computed in nine conscious dogs, and in four, stroke volume derived from dimensions was compared with right ventricular stroke volume measured with ultrasonic flow probes. A highly linear relation was observed, suggesting the accuracy of the shell subtraction method in vivo. Right ventricular end-systolic pressure-volume and stroke work/end-diastolic volume relations then were evaluated, and both proved to be highly linear in the right ventricle (both mean r = 0.99 +/- 0.01). Thus, the shell subtraction model allows a simple estimate of dynamic right ventricular volume in the intact heart and facilitates assessment of right ventricular performance in vivo.

Animals↗
PubMed1990

Comparative evaluation of clindamycin versus clindamycin plus tobramycin in the treatment of acute pelvic inflammatory disease.

Fifty-one hospitalized women were treated with either clindamycin phosphate alone (N = 23) or a combination of clindamycin phosphate plus tobramycin (N = 28) for community-acquired pelvic inflammatory disease. The overall regimen clinical success rates were 100 and 91% for the clindamycin/tobramycin and clindamycin-alone groups, respectively. Efficacy for patients with positive pre-treatment Neisseria gonorrhoeae cultures was eight of eight (100%) for the clindamycin/tobramycin group and seven of eight (88%) in the clindamycin-alone group. Of the total population studied, 15 of 51 (29%) had positive pre-treatment cultures for Chlamydia trachomatis, and a microbiologic cure was attained in 15 of 15 (100%). However, in two of 15 (14.5%), the patient did not return for the 6-week culture, although the culture at discharge from the hospital was negative. No serious adverse reactions were observed, although oral follow-up treatment with clindamycin had to be discontinued in one patient because of diarrhea, which resolved without additional therapy. The results suggest that intravenous clindamycin alone is a viable alternative to the use of clindamycin/tobramycin for women with acute pelvic inflammatory disease requiring hospitalization.

Adolescent↗
PubMed1989

Pap smears. Do them right and every year--forever!

The Pap smear is still an important screening test for cervical cytologic abnormalities. When performed according to appropriate screening protocols (with special attention to high-risk women), the test can help to identify mild dysplasia early, before it progresses to a malignant state. Correct technique in obtaining the smear and accurate reporting by a competent cytologic laboratory are critical for valid results.

Adolescent↗
PubMed1989

Pulsatile administration of oxytocin for augmentation of labor.

In a randomized study, 94 patients with term pregnancies underwent augmentation of labor with either continuous or pulsed (every 8 minutes) intravenous oxytocin infusion. There were no significant differences with respect to the maternal characteristics, cervical dilatation and effacement, induction-to-labor interval, induction-to-delivery interval, cesarean section rate, analgesia for labor, or low Apgar scores. No hyperstimulation was noted in either group. In each group, 20% of the patients had dysfunctional labor patterns, with coupling and tripling of the uterine contractions. The mean +/- SEM oxytocin administered in the pulsed-infusion group was significantly lower than that in the continuous-infusion group (2.1 +/- 0.4 versus 4.1 +/- 0.4 mU/minute; P less than .001). The mean +/- SEM total amount of oxytocin administered was 1300 +/- 332 mU for the pulsed group and 1803 +/- 302 mU for the continuous group, indicating that lower amounts of oxytocin were required for pulsed administration. Our study demonstrates that pulsatile administration of oxytocin is similar in efficacy to our standard continuous oxytocin infusion and requires a lower total amount and rate of oxytocin administered, which may afford a greater margin of safety.

Adult↗
PubMed1989

HIV infection in women.

Acquired immunodeficiency syndrome (AIDS) cripples the immune system, making the patient susceptible to a variety of infections and disorders. AIDS is caused by direct blood contact with a transmissible agent, now known as the human immunodeficiency virus (HIV). The pathophysiology, clinical disease, and treatment of HIV infection in women are discussed.

Female↗
PubMed1988

Multicenter clinical trials comparing cefotetan with moxalactam or cefoxitin as therapy for obstetric and gynecologic infections.

The clinical efficacy and safety of cefotetan was assessed in two multicenter clinical trials involving 335 evaluable patients hospitalized with obstetric and gynecologic infections. In Study I, cefotetan was compared with moxalactam and in Study II, cefotetan was compared with cefoxitin. The clinical response rate in Study I was 67 of 70 patients for cefotetan (96 percent) and 33 of 34 patients (97 percent) for moxalactam. In Study II, the clinical response rate was 138 of 147 patients in the cefotetan group (94 percent) and 76 of 84 patients in the cefoxitin group (91 percent). For the patients with bacteriologic response data, 196 of 205 cefotetan patients (96 percent), 23 of 24 moxalactam patients (96 percent), and 70 of 75 cefoxitin patients (93 percent) had a satisfactory bacteriologic response. Cefotetan was well tolerated and produced no major adverse reactions. The mean amount of cefotetan given was lower than that of moxalactam or cefoxitin.

Adult↗
PubMed1988

Interferon alpha-n1 (Wellferon) for refractory genital warts: efficacy and tolerance of low dose systemic therapy.

This multi-center trial compared two doses of parenterally administered interferon alpha-n1 (Wellferon) in men and women with recurrent/resistant genital warts. Patients received either 1 or 3 MU/m2 daily for 14 days, then 3 times weekly for 4 weeks; non-responders could receive an additional four weeks of treatment. A total of 107 patients were enrolled, and 102 were evaluable after six weeks of study. The principal dose comparison was in 57 women assigned alternately to the two doses. Median lesion measurements were reduced significantly from baseline at weeks 2, 4 and 6 in both groups. Statistical analysis showed no difference in response to 1 versus 3 MU/m2. The overall complete response (CR) plus partial response (PR) rate at week 6 was 69% for the two doses. Two additional groups of 21 women and 24 men were treated at the higher dose with CR plus PR rates of 75 and 50%, respectively. Week 10 disease evaluations for all groups showed 19 of 77 patients to be completely cleared. Of these 19, only one had recurrent disease at the end of the 6-month study period. Analysis of the incidence of symptomatic side effects showed a significantly higher frequency among women treated with 3 MU/m2 than among women treated with 1 MU/m2. Five dose reductions and two withdrawals for toxicity occurred, all in the high dose group. This study demonstrates that parenterally administered Wellferon produces clearance of resistant genital warts in many patients, and that rates of clearance do not appear to vary between groups receiving moderate or low dose therapy.

Adult↗