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Biomedical subjects

J E Thompson

Publications and source records attributed to J E Thompson.

At least 91 records · Page 5Linked to original sources
PubMed1996

Subungual melanoma of the hand.

Subungual melanoma is a rare but well-recognized tumor of the hand. Its management is ill defined and the factors influencing prognosis have not been well described. The clinicopathologic features of a series of 38 patients with subungual melanoma of the hand are reported. The median thickness was 3 mm, and only seven patients presented with pathologic stage I disease (American Joint Committee on Cancer [AJCC] system). Ulceration and lack of pigmentation were the only significant univariate prognostic indicators. There was no significant difference in local recurrence rates among patients whose amputation was carried out proximal or distal to the interphalangeal joint of the thumb or the middle of the middle phalanx in the other fingers. Management of the regional lymph node field based on the use of selective lymphadenectomy is described.

Adult↗
PubMed1996

Mesenteric angioplasty in the treatment of chronic intestinal ischemia.

PURPOSE: This study was undertaken to determine the safety and efficacy of percutaneous transluminal angioplasty (PTA) in the treatment of chronic mesenteric ischemia (CMI) in very high-risk surgical patients. METHODS: Twenty-four focal mesenteric stenoses treated from 1984 to 1994 by PTA in 19 patients with CMI were reviewed. All 19 patients were considered poor surgical candidates. Seventeen patients had classic symptoms of CMI, and two patients had atypical abdominal complaints. Vessels dilated included the superior mesenteric artery (18), celiac artery (3), inferior mesenteric artery (1), aorta-superior mesenteric artery vein graft (1), and aorta-splenic artery vein graft (1). Complete follow-up was possible in all patients, with the exception of one patient who had no symptoms when last seen 17 months after the procedure. RESULTS: PTA was technically successful in 18 of 19 patients (95%) and 23 of 24 stenoses (96%). The lone technical failure resulted in superior mesenteric artery dissection with thrombosis and bowel infarction; the patient died despite emergent laparotomy and revascularization (mortality rate, 5%). Complete symptomatic relief was attained in 15 patients (79%), with follow-up showing continued relief of symptoms for a mean of 39 months (range, 4 to 101 months). Partial symptomatic relief was attained in three patients. Recurrent symptoms developed in three patients (20%) at a mean interval of 28 months (range, 9 to 43 months). Repeat PTA performed in two patients provided good technical results and relief from clinical symptoms. One patient had a symptomatic axillary sheath hematoma that required surgical decompression. CONCLUSIONS: Mesenteric PTA is a valuable treatment option in patients who have CMI and are considered very high operative risks. The initial technical success rate is excellent, with the majority of patients having complete symptomatic improvement and continued relief of symptoms at short-term follow-up.

Aged↗
PubMed1996

Single breath CO2 analysis: description and validation of a method.

OBJECTIVES: To evaluate the performance of a newly developed single breath CO2 analysis station in measuring the airway deadspace in a lung model (study 1), and then to quantify the bias and precision of the physiologic deadspace measurement in a surfactant-depleted animal model (study 2). DESIGN: A prospective bench validation of a new technique of airway deadspace measurement using a criterion standard (study 1); a prospective, animal cohort study comparing a new technique of physiologic deadspace measurement with a reference method (Bohr-Enghoff method) (study 2). SETTING: A bench laboratory and animal laboratory in a university-affiliated medical center. SUBJECTS: A lung model (study 1), and adult sheep with induced surfactant deficiency (saline lavage) (study 2). METHODS: The single breath CO2 analysis station consists of a mainstream capnometer, a variable orifice pneumotachometer, a signal processor, and computer software with capability for both on- and off-line data analysis. Study 1: We evaluated the accuracy of the airway deadspace calculation using a plexiglass lung model. The capnometer and pneumotachometer were placed at the ventilator Y-piece with polyvinyl chloride tubing added to simulate increased airway deadspace. Segments of tubing were sequentially removed during each testing session to simulate decreasing deadspace. The calculated airway deadspace was derived from the single breath CO2 plot and compared with the actual tubing volume using least-squares linear regression and paired t-tests. Study 2: The accuracy of the physiologic deadspace measurement was examined in a saline-lavaged animal model by comparing the physiologic deadspace calculated from the single breath CO2 analysis station with values obtained using the Enghoff modification of the Bohr equation: deadspace/tidal volume ratio = (PaCO2-mixed expired PCO2)/PaCO2. MEASUREMENTS AND MAIN RESULTS: Study 1: Thirty-six measurements of calculated airway deadspace were made and compared with actual circuit deadspace during four different testing conditions. Measured airway deadspace correlated significantly with actual circuit deadspace (r2 = .99). The proportional error of the method was -0.8% with a 95% confidence interval from -3.6% to 1.9%. Study 2: A total of 27 pairs of measurements in four different animals were available for analysis. The derived physiologic deadspace/tidal volume ratio significantly correlated with the value obtained using the Bohr-Enghoff method (r2 = .84). The bias and precision of our physiologic deadspace calculation were .02 and .02, respectively, and the mean percent difference for the physiologic deadspace calculated from the single breath CO2 analysis station was 2.4%. CONCLUSIONS: Our initial experience with the single breath CO2 analysis station indicates that this device can reliably provide on-line evaluation of the single-breath CO2 waveform. In particular, estimation of the airway and physiologic deadspace under a variety of testing conditions was consistently within 5% of actual values. We feel that with further application and refinement of the technique, single breath CO2 analysis may provide a noninvasive, on-line monitor of changes in pulmonary blood flow.

Animals↗
PubMed1996

Effects of nitric oxide on hyperinflation-induced pulmonary hypertension in the isolated-perfused lung.

OBJECTIVE: To determine if nitric oxide decreases pulmonary vascular resistance in hyperinflation-induced pulmonary hypertension. DESIGN: Isolated-perfused lamb lung model. SETTING: Experimental animal laboratory in a university setting. SUBJECTS: Ten isolated-perfused lamb lungs harvested from subjects with a mean age of 29 days. INTERVENTIONS: After induction of anesthesia, endotracheal intubation, and mechanical ventilation, lungs were perfused via an extracorporeal circuit. Ventilatory pressures were set to provide tidal volumes of 10 mL/kg and ventilatory rates were adjusted to maintain a Paco2 of 40 +/- 5 torr (3.5 +/- 0.7 kPa). The perfusion system consisted of a blood reservoir, a membrane oxygenator, and a nonocclusive roller pump. Blood flow was increased progressively to 50 mL/kg/min, maintaining a pulmonary arterial pressure of < 25 mm Hg and a left atrial pressure between 2 and 5 mm Hg. End-expiratory lung volume was measured using a nitrogen washout method. Baseline data were collected after a 1-hr stabilization period. Lung volume was increased to achieve 25% (moderate hyperinflation) and 50% (severe hyperinflation) increments in pulmonary vascular resistance. Nitric oxide (80 parts per million) was administered to the preparation after each increment in lung volume. MEASUREMENTS AND MAIN RESULTS: Mean pulmonary arterial pressure, mean left atrial pressure, pulmonary vascular resistance, and static lung compliance were measured at baseline and after moderate and severe hyperinflation, both before and after nitric oxide administration. Significant decreases in pulmonary vascular resistance were found when the preparation was ventilated with nitric oxide at baseline (43% decrease) and during hyperinflation induced pulmonary hypertension at both moderate (31% decrease) and severe (23% decrease) levels of hyperinflation. CONCLUSIONS: Inhaled nitric oxide significantly reduces pulmonary vascular resistance, even when pulmonary hypertension is induced by airway hyperinflation and supraphysiologic lung volumes. These data suggest that the use of nitric oxide following lung transplantation may allow for effective management of pulmonary hypertension in patients who receive allografts from undersized donors. Further clinical experience will be crucial in precisely defining the range of donor-recipient size mismatch that can be adequately managed and the time course over which nitric oxide can be administered safely and effectively to these patients.

Animals↗
PubMed1996

Noninvasive determination of cardiac output using single breath CO2 analysis.

OBJECTIVE: To examine the utility of single breath CO2 analysis as a noninvasive measure of cardiac output. SETTING: An animal laboratory in a university-affiliated medical center. DESIGN: A prospective, animal cohort study comparing 21 parameters derived from single breath CO2 analysis with cardiac output determined by an ultrasonic flow probe. SUBJECTS: Six healthy adult sheep. METHODS: The single breath CO2 analysis station consists of a mainstream capnometer, a variable orifice pneumotachometer, a signal processor, and computer software with capability for both on- and off-line data analysis. Twenty-one derived components of the CO2 expirogram were evaluated as predictors of cardiac output. Cardiac output was manipulated by successive injections of a hydraulic constrictor placed around the inferior vena cava. MEASUREMENTS AND MAIN RESULTS: Thirty-four measurements of cardiac output were available for comparison with derived variables from the CO2 expirogram. Stepwise linear regression identified two variables that were most predictive of cardiac output: a) the angle between the slope lines for phase II and III of the CO2 expirogram divided by the volume of CO2 per breath (angle/mL CO2); and b) the slope of phase II. The multivariate equation was highly statistically significant and explained 94% of the variance (adjusted r2 = .94, p < .0001). The bias and precision of the calculated cardiac output were .00 and .23, respectively. The mean percent difference for the cardiac output estimate derived from the single breath CO2 analysis station was 0.36%. CONCLUSIONS: Our data indicate that analysis of the CO2 expirogram can yield accurate information about the cardiovascular system. Specifically, two variables derived from a plot of expired CO2 concentration vs. expired volume predict changes in cardiac output in healthy adult sheep with an adjusted coefficient of determination of .94. Prospective application of this technology in the setting of lung injury and rapidly changing physiology will be essential in determining the clinical usefulness of the technique.

Animals↗
PubMed1996

Vena cava injuries during laparoscopic cholecystectomy.

Two instances of vena cava injury occurring during insertion of a new trocar for laparoscopic surgery are presented. The mechanism of injury in each case was identical. These injuries are extremely rare, and fortunately both patients survived. Any new instrument that is purported to be an improvement over existing ones should be critically evaluated so that needless and unnecessary injuries such as these can be avoided.

Adolescent↗
PubMed1996

Abdominal tuberculosis: the surgical perspective.

The increasing incidence of pulmonary tuberculosis (TB) has led many to predict a corresponding increase in abdominal TB. This study reports the incidence, presentation, and outcome of abdominal TB to elucidate factors that might assist the surgeon to treat this potentially curable disease. A retrospective review of patients diagnosed with tuberculosis between 1993 and 1995 was performed at two hospitals. Diagnosis of abdominal TB was based on acid fast bacilli on tissue stains and/or culture. Seven patients were diagnosed with abdominal TB. Two patients were HIV positive; six were recent immigrants. Abdominal pain, fever, and significant weight loss were the most common symptoms. All preoperative radiologic tests failed to demonstrate findings suggestive of TB. All patients were brought to operation. Indications included perforated viscus (2), acute abdomen (1), small bowel obstruction (1), colocutaneous fistula (1), pelvic neoplasm (1), and biliary colic (1). Abdominal TB was either diagnosed or suspected intraoperatively in six patients. Postoperative anti-TB chemotherapy was promptly instituted. Although abdominal TB can be cured medically if treated early enough, the nonspecific presentation delays diagnosis in the majority of cases. Diagnosis of abdominal TB can be made or at least highly suspected intraoperatively such that anti-TB medications can be initiated promptly. Appropriate surgical therapy and prompt initiation of anti-tuberculosis medications can successfully treat abdominal TB.

Adolescent↗
PubMed1996

CT in adult supraglottitis.

We describe the CT appearance of supraglottitis and its complications in three adults. The most common CT findings were thickening of the epiglottis, aryepiglottic folds, false and true vocal cords, obliteration of the preepiglottic fa, thickening of the platysma muscle, and reticulation of the subcutaneous fat. Multiple loculated fluid-density collections consistent with abscesses were seen in one patient. Although the diagnosis of supraglottitis is generally made on the basis of the patient's history and by direct endoscopy, CT may be used to confirm the diagnosis when an adequate laryngoscopic examination cannot be performed. CT is also useful in evaluating the complications of this disorder.

Adult↗
PubMed1996

MR in children with L-carnitine deficiency.

PURPOSE: To describe the MR imaging findings in five children with proved L-carnitine deficiency. METHODS: MR imaging studies (five without contrast, two with contrast) were obtained in five children (mean age, 9 years) who presented with stroke symptoms and who proved to have L-carnitine deficiency as established by serum levels. RESULTS: In three of five patients, infarctions were confined to arterial distributions; one patient had a hemorrhagic infarction in one frontoparietal region; and one patient had only nonspecific periventricular white matter T2 hyper-intensities. Serum L-carnitine levels normalized after correction; sequelae included seizures in two patients, hemiparesis in one patient, normal outcome in one patient, and death in one patient. CONCLUSION: L-Carnitine deficiency is a rare metabolic disorder leading to cerebral infarctions, as seen in our five patients, and should be considered in the differential diagnosis of children who have had a stroke, particularly when associated with hypoglycemia and myopathy.

Adolescent↗
PubMed1996

Why should midwives be concerned with ethics?

Is there such a thing as midwifery ethics? Yes, there is. As human beings (moral agents), midwives are to be ethical, moral, responsible persons and professionals. Midwives work in moral relationships with other persons. They serve by the moral standards of their profession as now embodied in written codes of ethics, a profession that is part of the larger health care profession. As part of the professional world, midwives participate in the general standard that to be professional is to be ethical and to be unethical is to be unprofessional. The professions, in turn, are part of what Eric Fromm calls "human ethics." If midwives are to be ethical, we suggest they need to understand ethics and to reason morally. Better health care for all is the result.

Ethics, Nursing↗
PubMed1995

I kappa B-beta regulates the persistent response in a biphasic activation of NF-kappa B.

We have cloned the cDNA encoding I kappa B-beta, one of the two major I kappa B isoforms in mammalian cells. The recombinant I kappa B- beta protein interacts with equal affinity to p65 and c-Rel and does not exhibit a preference between these Rel proteins. Instead the primary difference between I kapp B-alpha and I kappa B-beta is in their response to different inducers of NF-kappa B activity. One class of inducers causes rapid but transient activation of NF-kappa B by primarily affecting I kappa B-alpha complexes, whereas another class of inducers causes persistent activation of NF-kapa B by affecting both I kappa B-alpha and I kappa B-beta complexes. Therefore, the overall activation of NF-kappa B consists of two overlapping phases, a transient phase mediated through I kappa B-alpha and a persistent phase mediated through I kappa B-beta.

Amino Acid Sequence↗
PubMed1995

Isolation of nonsedimentable lipid-protein particles from insect intestine.

Nonsedimentable lipid-protein particles have been isolated from intestinal tissue of the American cockroach, Periplaneta americana. Most of the particles were within the range 30-50 nm in diameter and appear to originate from larger structures. Lipid analysis of the particles showed them to be enriched in neutral lipid components relative to microsomal membranes. Specifically, there is a decline in the amounts of phosphatidylcholine and phosphatidylethanolamine in the nonsedimentable particles compared with the microsomal membranes. Also, in contrast to microsomal membranes, the particles have a higher content of phosphatidic acid along with 1,2- and 1,3-diacyglycerols, free fatty acids and an unidentified lipid that co-migrates with sterol ester, wax ester and hydrocarbon standards in thin layer chromatograms. The cytosol, separated from the particles by ultrafiltration, contained phosphatidic acid, free fatty acids and the unidentified lipid. By contrast, the composition of neutral lipids in the cytosol resembles that of the particles. SDS-PAGE analysis of microsomal membranes, the particles and particle free cytosol shows an enrichment of low molecular weight proteins in the particles and cytosol. The particles and cytosol appear to possess proteolytic activity that is distinguishable from that of corresponding microsomal membranes since the incubation of these components with BSA resulted in the formation of distinct polypeptides. Many characteristics of these particles resemble those of the deteriosomes that have been isolated from plant tissue.

Animals↗
PubMed1995

Inhaled nitric oxide and hemodynamic evaluation of patients with pulmonary hypertension before transplantation.

OBJECTIVES: We investigated the effect of inhaled nitric oxide and infused acetylcholine in patients with pulmonary hypertension undergoing cardiac catheterization before cardiopulmonary transplantation. BACKGROUND: The fate of patients under consideration for transplantation of the heart or lungs, or both, is influenced by the evaluation of their pulmonary vascular reactivity. METHODS: We evaluated 11 patients who were classified into two groups on the basis of mean left atrial pressure > 15 mm Hg (group I, n = 6) or < or = 15 mm Hg (group II, n = 5). All patients inhaled nitric oxide at 80 ppm. This was preceded by an infusion of 10(-6) mol/liter of acetylcholine in seven consecutive patients (n = 3 in group I, n = 4 in group II). RESULTS: In group I, inhaled nitric oxide decreased pulmonary artery pressure from (mean +/- SE) 71 +/- 13 to 59 +/- 10 mm Hg (p < 0.05), pulmonary vascular resistance from 14.9 +/- 3.8 to 7.6 +/- 1.7 Um2 (p < 0.05) and intrapulmonary shunt fraction from 17.8 +/- 3.6% to 12.7 +/- 2.1% (p < 0.05). Left atrial pressure tended to increase from 27 +/- 4 to 32 +/- 5 mm Hg (p = 0.07). In group II pulmonary vascular resistance decreased in response to nitric oxide from 36.4 +/- 9.0 to 31.1 +/- 7.9 Um2 (p < 0.05). Cardiac index, systemic pressure and resistance did not change in either group. Seven patients who received acetylcholine had no significant alteration in pulmonary hemodynamic variables. CONCLUSIONS: These preliminary observations suggest that nitric oxide is a potent pulmonary vasodilator with minimal systemic effects. It may be useful in discriminating patients needing combined heart and lung transplantation from those requiring exchange of the heart alone.

Acetylcholine↗