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Biomedical subjects

J Segal

Publications and source records attributed to J Segal.

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

Coronary blood flow reserve in acute aortic regurgitation.

OBJECTIVES: This study sought to determine the impact of acute aortic regurgitation on coronary blood flow reserve and phasic epicardial coronary blood flow in closed-chest dogs. BACKGROUND: Hemodynamic changes in acute aortic regurgitation are known to precipitate myocardial ischemia. Coronary blood flow reserve has not been studied in closed-chest experimental preparations with acute aortic regurgitation. METHODS: Graded temporary acute aortic regurgitation was produced in 11 mongrel dogs. Phasic coronary blood flow velocities were measured using a Doppler guide wire. Coronary flow reserve was defined as the ratio of the time average of spectral peak velocity after administration of papaverine to that of the baseline state. RESULTS: Under control conditions (mean [+/- SEM] diastolic blood pressure 82.2 +/- 4.5 mm Hg), coronary flow reserve was 3.51 +/- 0.27 with predominantly diastolic epicardial coronary blood flow. With mild acute aortic regurgitation (diastolic blood pressure 61.8 +/- 3.0 mm Hg), coronary flow reserve decreased to 2.38 +/- 0.27, with an increase in phasic systolic epicardial coronary blood flow. At the onset of moderate acute aortic regurgitation (diastolic blood pressure 42.1 +/- 0.9 mm Hg), coronary flow reserve declined further to 1.46 +/- 0.12, and the phasic systolic epicardial coronary blood flow became more prominent. With severe aortic regurgitation (diastolic blood pressure 29.2 +/- 2.2 mm Hg), coronary flow reserve reached 1.20 +/- 0.05, and the phasic epicardial coronary blood flow pattern was found to be predominantly systolic with retrograde diastolic flow. The ratio of diastolic to systolic pressure-time indexes with severe aortic regurgitation suggested subendocardial underperfusion. CONCLUSIONS: This study demonstrates a marked decline in coronary blood flow reserve and documents a progressive change in the phasic epicardial blood flow to a predominantly systolic pattern with increasing degrees of acute aortic regurgitation.

Animals↗
PubMed1994

Postmenopausal intrauterine fluid collection: correlation between ultrasound and hysteroscopy.

Postmenopausal intrauterine fluid is an alarming sign related to malignancy. Twenty postmenopausal women with intrauterine fluid were prospectively studied by means of sonographic evaluation, and hysteroscopic and histological examinations, to determine the correlation between ultrasound and hysteroscopy. All patients underwent endovaginal sonography, followed by hysteroscopy. Biopsies were performed on all patients with abnormal endometrium, and randomly on selected patients with normal or atrophic endometrium. In patients with abnormal endometrial structure and thickness (< 4 mm), two cases of endometrial cancer were histologically detected and one was revealed by cytology (Pup smear). Seventeen patients with thin endometrium (<or= 4 mm) had no pathology. Sonographic, hysteroscopic and histological findings correlated well in all cases.

Journal Article↗
PubMed1994

A validation study of the Dementia Questionnaire.

OBJECTIVE: To determine the validity of the Dementia Questionnaire (a semistructured informant interview) for the diagnosis of dementia. DESIGN: Comparison of dementia status determined by a telephone-administered informant questionnaire with the criterion standard of clinical diagnosis established by examination and laboratory studies. SETTING: Gerontology Research Center, the Baltimore Longitudinal Study of Aging. SUBJECTS: Volunteer cohort of 42 men and 32 women aged 68 to 97 years. Subjects were selected from strata defined by Blessed Information Memory Concentration Test scores, with oversampling of borderline scores (3 to 10). MAIN OUTCOME MEASURES: Sensitivity and specificity of the Dementia Questionnaire in comparison with the criterion standard of clinical diagnosis. SECONDARY OUTCOME MEASURE: Interrater reliability (kappa coefficient). RESULTS: Sensitivity and specificity for dementia were 100% and 90%, respectively. Most false-positive findings were from subjects with cognitive impairment that did not meet criteria for dementia (Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition. Interrater reliability was high (kappa = 0.83). CONCLUSION: The Dementia Questionnaire can be used effectively in research studies to screen for dementia.

Aged↗
PubMed1994

Jugular bulb oxygen saturation monitoring for evaluating cerebral ischemia.

Traumatic brain injury challenges the health care team to employ treatment modalities to prevent secondary brain damage. Initially, the focus was on controlling intracranial pressure and maintaining cerebral perfusion pressure. It is now known it is more critical to determine whether flow matches the brain's metabolic needs as indicated by the cerebral metabolic rate of oxygen. Measuring cerebral metabolic rate of oxygen, the brain's oxygen consumption, is not attained easily due to technical reasons; therefore, it is calculated from more easily attained values (cerebral blood flow x arteriovenous oxygen content difference [AVDO2]). Continuous monitoring of cerebral venous O2 saturation is accomplished via the jugular vein. In most incidences where arterial O2 saturation is stable, then AVDO2 is inversely proportional to the jugular bulb O2 saturation. Jugular bulb O2 saturation, and therefore AVDO2, can be used to evaluate cerebral O2 supply and demand balance as it correlates with cerebral blood flow, with important exceptions as discussed. The most immediate value of jugular bulb O2 saturation monitoring lies in its ability to guide the effects of therapy on O2 supply and demand balance.

Blood Gas Analysis↗
PubMed1994

Estrogen replacement in postmenopausal women: are we currently overdosing our patients?

As there are no proven optimal serum estradiol levels, we sought to evaluate the pharmacokinetic profiles of serum estradiol levels following a single oral dose of 2 mg estradiol and 1 mg of estriol (Trisequens) among 26 surgically induced, postmenopausal patients. Their serum estradiol levels were periodically measured over 24 h following oral administration of the drug. They were divided into two groups according to the computed hourly mean estradiol values: group A, < 250 pg/ml/h ( < 918 pmol/l/h) and group B, > 250 pg/ml/h ( > 918 pmol/l/h). The mean peak estradiol concentrations were noted 2 h after drug administration and amounted to 595 +/- 190 pg/ml (2,184 +/- 697 pmol/l) in the entire cohort; 435 +/- 117 pg/ml (1,597 +/- 430 pmol/l) in group A and 712 +/- 142 pg/ml (2,614 +/- 521 pmol/l) in group B (p < 0.001). The mean total area under the curve in group A was 4,887 pg/ml (17,940 pmol/l), which was significantly lower than that of 7,995 +/- 652 pg/ml/24 h (29,350 +/- 2,393 pmol/l/24 h) found for group B (p < 0.001). The mean body mass index showed a significant difference (p < 0.003) between group A and group B (29.4 +/- 0.56 vs. 24.3 +/- 0.24). We found that 57% of our patients were exposed to excessively high levels of estradiol during the 24-hour period following drug ingestion. We advise monitoring estradiol levels and individualizing estrogen replacement therapy, to avoid the long-term exposure of postmenopausal patients to superphysiological estradiol levels.

Adult↗
PubMed1993

Applications of coronary flow velocity during angioplasty and other coronary interventional procedures.

Previous studies utilizing Doppler catheters to assess blood flow immediately following coronary artery interventions have failed to demonstrate significant improvement in proximal coronary artery velocities or vasodilator reserve. Measurement of blood flow velocity, flow reserve, and the phasic diastolic/systolic velocity ratio in the distal coronary artery has been performed following various interventional procedures utilizing a low profile (.018 in) Doppler angioplasty guidewire. Following balloon angioplasty in 38 patients, average peak velocity increased significantly from 19 +/- 12 to 35 +/- 16 cm/sec in the distal coronary artery. The diastolic/systolic flow ratio improved from 1.3 +/- 0.5 to 1.8 +/- 0.5 and coronary flow reserve remained unchanged. Similar improvement in distal mean velocities (200%) versus proximal mean velocities (90% increase), and improvement in phasic velocity patterns, total velocity integral, and peak diastolic velocity were also noted in a separate study of 29 patients, before and after balloon angioplasty. Following excimer laser angioplasty in 10 patients, average peak velocity in the distal coronary artery was noted to increase from 6.3 to 13.0 cm/sec following laser alone, with a further increase to 20.6 cm/sec following adjunctive balloon angioplasty. The diastolic/systolic flow ratio increased from a mean value of 1.1 to 2.0 following laser recanalization, with a further increase to 2.9 following adjunctive balloon angioplasty. Following directional coronary atherectomy only modest improvement in distal average peak velocity was noted (24.7 to 31.2 cm/sec), with no significant change in diastolic/systolic velocity ratio (1.78 vs 2.04) immediately following the procedure. Measurement of distal flow velocity parameters performed immediately following coronary interventions may prove useful in assessing the hemodynamic result of these interventions and may prove useful in clinical decision making.

Angioplasty, Balloon, Coronary↗
PubMed1993

Antibiotic for cesarean section: the case for 'true' prophylaxis.

OBJECTIVES: To assess prospectively the efficiency and safety of two extended spectrum cephalosporins used as pre-operative prophylaxis in nonelective cesarean sections, and compare the results to those of a third group of patients that received cefamezine post cord clamping. METHODS: Two hundred and forty one patients undergoing a nonscheduled cesarean section were assigned to receive either cefonicid or ceftriaxone prior to skin incision. These patients were followed prospectively for infectious and fetal complications. The outcome of these patients was also compared with another group of 194 patients that received cefamezine prophylaxis post cord clamping, and whose data were collected retrospectively. Chi-square analysis of variance were performed with P < 0.05 considered significant. RESULTS: There were no significant differences in the febrile complications among the two groups of patients that received pre-operative prophylaxis. However, these patients had significantly less wound infections (P = 0.008) and a significantly shorter hospital stay (P < 0.001) than the patients who received their prophylactic antibiotics post cord clamping. CONCLUSIONS: Extended-spectrum cephalosporins, when given pre-operatively, are both effective and safe, and may have an advantage over intra-operative first generation cephalosporins in the reduction of post cesarean section infectious morbidity.

Cefazolin↗
PubMed1993

Assessing the hemodynamic significance of coronary artery stenoses: analysis of translesional pressure-flow velocity relations in patients.

OBJECTIVES: The purpose of this study was to examine the relation among the angiographic severity of coronary artery lesions, coronary flow velocity and translesional pressure gradients. BACKGROUND: Determination of the clinical and hemodynamic significance of coronary artery stenoses is often difficult and inexact. Angiography has been shown to be an imperfect tool for determining the physiologic significance of eccentric or irregular coronary lumen narrowing. METHODS: Using a 0.018-in. (0.046 cm) intracoronary Doppler-tipped angioplasty guide wire, spectral flow velocity data both proximal and distal to coronary stenoses were compared with translesional pressure gradient measurements and angiographic data obtained during cardiac catheterization in 101 patients. There were 17 patients with normal angiographic findings and 84 with coronary artery disease, with lesions ranging from 28% to 99% diameter narrowing. Patients with coronary disease were assigned to two groups on the basis of translesional gradients at rest. Group A (n = 56) had gradients < 20 mm Hg, and Group B (n = 28) had gradients > or = 20 mm Hg. RESULTS: Proximal average peak velocity, diastolic velocity integral and total velocity integral were slightly but statistically lower in Group A; however, the distal average peak velocity and diastolic and total velocity integrals were all markedly (all p < 0.01) decreased in patients with gradients > or = 20 mm Hg (Group B). In addition, the ratio of proximal to distal total flow velocity integral was higher in Group B (2.4 +/- 1.0) than in group A (1.1 +/- 0.3, p < 0.001). There was a strong correlation between translesional pressure gradients and the ratios of the proximal to distal total flow velocity integrals (r = 0.8, p < 0.001), with a weaker relation between quantitative angiography and pressure gradients (r = 0.6, p < 0.001). In angiographically intermediate stenoses (range 50% to 70%), angiography was a poor predictor of translesional gradients (r = 0.2, p = NS), whereas the flow velocity ratios continued to have a strong correlation (r = 0.8, p < 0.001). Only two patients with a proximal/distal total flow velocity ratio < 1.7 had a translesional gradient > 30 mm Hg. Both patients had a very proximal lesion in a nonbranching right coronary artery. CONCLUSIONS: These data demonstrate that in branching human coronary arteries, a close relation exists between translesional hemodynamics and distal coronary flow velocity. Translesional coronary flow velocity is a new and easily applicable method for determining the hemodynamic significance of coronary artery stenoses that is superior to angiography and can be applied at the time of diagnostic catheterization. These data will provide a rational approach to making decisions on the use of coronary interventional techniques when angiographic findings are questionable.

Adult↗
PubMed1993

Analysis of coronary blood flow velocity dynamics in angiographically normal and stenosed arteries before and after endolumen enlargement by angioplasty.

OBJECTIVES: This study was designed to assess whether the spectral waveform of coronary velocity on Doppler study is characteristically altered in the presence of significant stenosis with normalization of the spectral waveform after relief of endolumen obstruction. BACKGROUND: Although coronary flow reserve determinations have provided physiologic information complementary to the angiographic percent diameter narrowing, flow velocity measurements have been limited to proximal arteries with inconsistent results after angioplasty. A 12-MHz Doppler guide wire permits flow velocity determination in the proximal and distal coronary artery with fast Fourier spectral analysis. METHODS: With the Doppler guide wire, proximal arterial flow velocity and flow reserve measurements in 17 angiographically normal arteries were compared with measurements in 29 significantly stenosed arteries. Proximal and distal flow velocity measurements were also obtained before and after angioplasty of the 29 abnormal arteries. Velocity spectrum was digitized to compute peak diastolic velocity, peak systolic velocity, mean velocity, diastolic/systolic velocity ratio and first third and first half flow fraction. RESULTS: Compared with proximal stenosed arteries, proximal normal arteries had significantly higher peak diastolic velocity (64 +/- 26 cm/s vs. 41 +/- 26 cm/s) and higher coronary vasodilator reserve (2.3 +/- 0.8 vs. 1.6 +/- 0.7). Normal arteries had higher flows in the first third and first half of the coronary cycle (46 +/- 3% vs. 39 +/- 7% and 65 +/- 2% vs. 56 +/- 10%, respectively). Before angioplasty, coronary velocity variables were significantly lower distal than proximal to the stenosis. After angioplasty, there was a greater mean increase in distal velocities (200% vs. 90% for the proximal arteries) that resulted in near equalization of proximal and distal mean velocity and a significant reduction in proximal/distal mean velocity ratio (2.4 +/- 1.7 vs. 1.2 +/- 0.4). CONCLUSIONS: Before angioplasty, abnormal coronary flow velocity dynamics are more marked distal than proximal to the stenosis. Greater increase in coronary flow velocities in the distal circulation after relief of endolumen obstruction results in a significant reduction in the proximal/distal flow velocity ratio. Thus, normalization of Doppler-derived flow velocity variables with marked reduction of the proximal/distal flow velocity ratios parallels angiographic success and may prove useful as an additional end point measurement in interventional cases with questionable angiographic findings.

Angioplasty, Balloon, Coronary↗
PubMed1993

Treatment of recurrent spontaneous abortions by immunization with paternal lymphocytes induces immunosuppression by placental isoferritin.

PROBLEM: The immunological mechanism leading to an effective vaccination of unexplained habitual aborters with paternal lymphocytes is not yet elucidated. Since previous studies revealed that immunosuppression by placental isoferritin (PLF) may play an important role in the down regulation of the immune system during pregnancy, it was of interest to investigate whether alloimmunization activates immunosuppression by PLF. METHOD: The immunosuppressive effect of PLF or anti-PLF CM-H-9 monoclonal antibody (MAb) was studied by a one-way mixed lymphocyte reaction (MLF) of alloimmunized women and their husbands. RESULTS: It was found that vaccination of the women with paternal lymphocytes resulted in in vitro immunosuppression by PLF as well as by CM-H-9 MAb, reaching the highest effect after three vaccinations (38 +/- 8 and 42 +/- 10%, respectively). The increase in PLF immunosuppressive effect was accompanied by the appearance of serum antipaternal human leukocyte antigen cytotoxic antibodies. However, there was no correlation between the degree of suppression and titer of antibodies. The study group was too small to reach a significant correlation between degree of immunosuppression and pregnancy outcome. CONCLUSIONS: Although it may be of value to measure the inhibitory effect of PLF in one-way MLR as an index of immunosuppression, further studies are needed to establish whether it is a relevant predictor of a successful pregnancy.

Abortion, Habitual↗
PubMed1993

Augmentation of coronary blood flow by intra-aortic balloon pumping in patients after coronary angioplasty.

BACKGROUND: Controversy exists regarding the ability of intra-aortic balloon pumping to increase coronary blood flow in patients with obstructive coronary artery disease. To assess the effects of intra-aortic balloon pumping on coronary hemodynamics, we measured coronary blood flow velocity with a 0.018-in. Doppler-tipped angioplasty guide wire in 15 patients who received an intra-aortic balloon pump for typical clinical indications. METHODS AND RESULTS: Intra-aortic balloon pumping augmented diastolic pressure 83 +/- 35%. In nine patients before angioplasty, peak diastolic coronary flow velocity beyond the stenosis (mean diameter narrowing, 95 +/- 7%) was 5.3 +/- 9.6 cm/sec and was unaffected by intra-aortic balloon pumping. After angioplasty, the improved coronary luminal diameter narrowing (n = 12; mean narrowing, 18 +/- 12%) was associated with increased distal diastolic flow velocity integral and peak diastolic and mean velocities (13.3 +/- 8.4 units: 36.4 +/- 18.3 and 24.0 +/- 11.4 cm/sec, respectively; all p < 0.01 versus before angioplasty), which were further augmented (36 +/- 37%, 54 +/- 49%, and 26 +/- 17%, respectively; all p < 0.01) with intra-aortic balloon pumping. Intra-aortic balloon pumping did not significantly increase the distal systolic velocity integral (10 +/- 59%) or peak systolic velocity (3 +/- 33%). Similar degrees of balloon pump augmentation of distal coronary flow velocity values were observed in five angiographically normal reference arteries in four patients. CONCLUSIONS: These data demonstrate lack of significant flow improvement beyond most critical stenoses with intra-aortic balloon pumping and the unequivocal restoration and intra-aortic balloon pump-mediated augmentation of both proximal and distal coronary blood flow velocities after amelioration of severe coronary obstructions in patients after successful coronary angioplasty.

Aged↗
PubMed1993

Prolonged barbiturate therapy in a patient with closed head injury and jugular venous thrombosis.

The case of a patient who sustained a severe closed head injury complicated by jugular venous thrombosis is presented. Early problems with intracranial pressure were related to bifrontal intracerebral contusions. Jugular vein thrombosis became manifest clinically late in the patient's course and was verified by Doppler ultrasonography. Late problems with intracranial hypertension were presumed to be due to decreased cerebral outflow secondary to the thrombosis. The patient required 4 weeks of a high-dose regimen of pentobarbital to control his intracranial pressure. This is an exceptionally long period of time for a patient to be in barbiturate coma for a closed head injury and still make a satisfactory recovery. The incidence, etiology, prevention, and treatment of upper extremity and jugular venous thrombosis are discussed. The ramifications of jugular venous thrombosis in neurosurgical patients are discussed.

Adult↗
PubMed1993

Percutaneous catheterization of the jugular bulb with a Doppler probe: technical note.

On-line measurement of jugular venous bulb oxygen saturation may be of clinical value in patients with head injuries. Cannulation of the jugular bulb may be technically difficult in this group of patients. Trendelenberg positioning and head rotation may be associated with increased morbidity or mortality. A technique is described whereby catheterization can be performed with the head of the bed elevated and the neck in a neutral position. A needle with a Doppler probe is used to distinguish between the carotid artery and the internal jugular vein. The needle and the probe are then directed to the audible signal representative of the jugular vein. Once the vein is penetrated, placement of a fiberoptic oxygen saturation catheter is performed in the usual fashion. This technique allows auditory feedback to guide the course of the needle and decreases the morbidity that may be associated with the "blind" technique.

Blood Gas Analysis↗
PubMed1993

Erythropoietin profile in spinal cord injured patients.

Patients with spinal cord injury (SCI) have a high incidence of anemia. Intact erythropoietin (EPO) production is essential to the maintenance of erythrocyte mass and prevention and correction of anemia. However, the effect of chronic SCI on EPO production remains unclear. We measured plasma EPO concentration in 83 men with longstanding SCI and a group of normal able-bodied individuals. The SCI patients showed a significant reduction in hematocrit, a high prevalence of anemia, and an increased plasma EPO concentration. Active smokers showed a significantly higher hematocrit and lower EPO concentration than nonsmokers. No significant difference was found in hematocrit or EPO between individuals with paraplegia and those with quadriplegia. A negative correlation was found between EPO and hematocrit in SCI patients lacking significant lung disease. Thus, in the absence of renal insufficiency, EPO response to anemia is qualitatively preserved in SCI patients and is largely independent of the level of injury.

Adult↗