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Biomedical subjects

P J Leo

Publications and source records attributed to P J Leo.

16 recordsLinked to original sources
PubMed2001

Collisional frequency shifts in 133Cs fountain clocks.

We present a theoretical analysis of the density dependent frequency shift in Cs fountain clocks using the highly constrained binary collision model described by Leo et al. [Phys. Rev. Lett. 85, 2721 (2000)]. We predict a reversal in the clock shift at temperatures near 0.08 microK. Our results show that s waves dominate the collision process. However, as a consequence of the large scattering lengths in Cs the clock shift is strongly temperature dependent and does not reach a constant Wigner-law value until temperatures are less than 0.1 nK.

Journal Article↗
PubMed2000

The utility of maternal creatine kinase in the evaluation of ectopic pregnancy.

This investigation was designed to evaluate the utility of maternal creatine phosphokinase (CPK) in predicting the presence of an ectopic pregnancy (EP) in an emergency department (ED) setting. Twenty-one patients with the diagnosis of EP were randomly matched (1:1) with pregnant patients who subsequently ruled-out for EP. Serum CPK values at presentation were compared between the groups using two-tailed ANOVA, odds ratio, and frequency tables were generated using our a priori hypothesis that a serum CPK of >70 mlU/dL may be useful as a predictor of EP. The mean serum CPK was 118mlU/dL in the EP group and 64 mlU/dL in the non-EP group (P < .0031). Controlling for age, race, and gestational age, there was an association between elevated serum CPK and EP in our study population (with an odds ratio of 6.5). The categorical evaluation (with 95% confidence interval [CI]) of CPK (>70 mIU/dL) as a predictor of EP follows: sensitivity - 100% (80.8 to 100); specificity-- 61.9% (38.7 to 81); PV(+) - 72.4% (52.5 to 88.6); PV(-) - 100% (71.7 to 100). We therefore conclude that a CPK level >70 mIU/dL may serve as an important adjuvant diagnostic tool in ruling-out EP.

Adult↗
PubMed1998

Comparative knowledge and practice of emergency physicians, cardiologists, and primary care practitioners regarding drug therapy for acute myocardial infarction.

OBJECTIVES: This study assesses the knowledge and practice of emergency physicians regarding the treatment of acute myocardial infarction (AMI) and compares the results with previously published data on cardiologists and primary care practitioners. BACKGROUND: Debate surrounding the respective roles of emergency physicians, primary care practitioners, and specialists figures prominently in discussions regarding the nation's evolving health-care system. Data are lacking about the comparative knowledge and practice of emergency physicians, cardiologists, and primary care practitioners regarding conditions commonly treated by all three groups, eg, AMI. METHODS: A survey of 1,045 emergency physicians, nationally, was conducted in 1995 regarding five short-term pharmacologic interventions employed for many years in the standard treatment of AMI. The emergency physicians were questioned about the effect on survival of each intervention and the likelihood that they would prescribe each intervention. The findings were then compared with previously published data on the knowledge and practice of cardiologists and primary care practitioners obtained in New York and Texas in 1993. Identical clinical queries and eligibility criteria were employed in all groups. RESULTS: The responding emergency physicians' knowledge was similar or significantly greater than that of responding cardiologists for the effect on survival of most of the short-term interventions, and their practice patterns were similar or significantly better than responding cardiologists for all interventions studied. Emergency physicians and cardiologists had significantly better knowledge and practice in this area compared with responding primary care practitioners. CONCLUSIONS: For the management of AMI, emergency physicians, on average, have a similar or greater awareness of the effects on survival and similar or better practice patterns regarding most acute pharmacologic interventions when compared with those of cardiologists; both groups, on average, have a superior knowledge and practice when compared with primary care practitioners. These results illustrate the importance of emergency medicine and support further consideration of an expanding role for the emergency physician in the nation's evolving health-care system.

Adrenergic beta-Antagonists↗
PubMed1997

Cocaine-associated intestinal gangrene in a pregnant woman.

A 31-year-old pregnant woman who was an active cocaine abuser presented to our emergency department five times in 1 week for abdominal pain and vomiting. She continued to use cocaine regularly despite having abdominal pain. Her fifth admission was for seizures. There were no objective signs of peritoneal inflammation and the rectal guiac examination was repeatedly negative. The patient progressed to severe septic shock. Intraabdominal sepsis and/or bowel perforation was suspected. Exploratory laporatomy revealed gangrene and perforation of the small intestine and fecal peritonitis. She rapidly developed multiorgan failure and died. Gastrointestinal complications resulting from cocaine use are uncommon. Our case is unique in that the patient was pregnant, used cocaine by the intranasal route, and lacked objective signs of acute abdomen. Emergency physicians should be aware of the morbidity associated with the use of cocaine.

Adult↗
PubMed1997

Postoperative mitral valve abscess. A case report.

The authors report a case of a patient with postoperative perimitral bioprosthetic abscess and probable systemic embolization. The location of the abscess is not common and the use of porcine bioprostheses is supposedly associated with a low rate of embolic complications. Because of the high mortality and morbidity, it is stressed that patients with prosthetic valve endocarditis should be managed aggressively with surgery.

Abscess↗
PubMed1996

Phenylpropanolamine and associated myocardial injury.

We report the cases of two patients without significant past medical history in whom developed myocardial injury attributed to the use of anorectic agents containing phenylpropanolamine. The pharmacologic properties of phenylpropanolamine and the current management of common adverse reactions to phenylpropanolamine are briefly reviewed.

Adolescent↗
PubMed1996

The role of serum phosphate level and acute ischemic bowel disease.

The objectives of this study were to determine whether an elevated serum phosphate level is predictive of acute ischemic bowel disease and whether it serves as a prognostic indicator in patients with intestinal ischemia. A retrospective chart review was performed at an urban teaching hospital emergency department. Twenty-three patients with documented acute ischemic bowel disease from 1990 through 1994 were compared with 27 patients with acute abdominal disease entities unrelated to intestinal ischemia. The sensitivity, specificity, and positive and negative predictive values of serum phosphate were 26%, 85%, 60%, and 58% respectively. Levels of phosphate in patients with intestinal ischemia versus controls were 4.20 versus 3.41 mg/dL (P = .1338). The length of bowel necrosis in the experimental group with elevated phosphate versus normal phosphate level was 57.53 cm versus 99.00 cm (P = .4132). Although not statistically significant, linear regression revealed slightly positive correlations in those with elevated phosphate versus normal phosphate level (in the experimental group) with the length of bowel necrosis and duration of hospital stay as r= .155 (P = .4813) and r= .134 (P= .5418), respectively. Serum phosphate level independently has no diagnostic or prognostic value in acute ischemic bowel disease.

Acute Disease↗
PubMed1996

Serial electrocardiograms for chest pain patients with initial nondiagnostic electrocardiograms: implications for thrombolytic therapy.

OBJECTIVES: To determine the proportion of acute myocardial infarction (AMI) patients without ST-segment elevation who subsequently develop ST-segment elevation during their hospital courses; and to compare demographics and presenting features of AMI patient subgroups: those with initial ST-segment elevation, those with in-hospital ST-segment elevation, and those with no ST-segment elevation. METHODS: A retrospective cohort analysis of admitted chest pain patients who had a hospital discharge diagnosis of AMI was performed. Each chart was examined for initial ECG interpretation, serial ECG analysis, patient age, gender, cardiac risk factors, in-hospital survival, time between sequential ECGs, and number of ECGs performed within the first 48 hours of hospital admission. RESULTS: Of the 114 charts reviewed, 20 patients had ECGs meeting thrombolytic criteria on arrival. Of the 94 AMI patients who had nondiagnostic ECGs on arrival, 19 (20%) subsequently developed ECG changes meeting thrombolytic criteria. Seven patients developed these changes within eight hours of the initial ECG, four from eight to 12 hours after, two from 12 to 24 hours after, and six more than 24 hours after. Most patients who had documented AMIs did not develop ECG criteria for thrombolytic therapy during their hospitalizations. Male gender and smoking history were more commonly associated with late ST-segment elevation for those presenting with nondiagnostic ECGs. All the patients who had late diagnostic ECG changes survived to hospital discharge. Serial ECGs were performed more frequently in the group who had initially diagnostic ECGs and least frequently in the group who did not develop ST-segment elevation during their hospitalizations. CONCLUSIONS: Most patients with AMI do not meet ECG criteria for the administration of thrombolytic therapy. A significant minority (20%) of the admitted chest pain patients with subsequently confirmed AMIs developed ECG criteria for thrombolytics during their hospitalizations. Further attention to such patients who have delayed ST-segment elevation is warranted. A standardized in-hospital serial ECG protocol should be considered to identify admitted patients who develop criteria for thrombolytic or other coronary revascularization therapy.

Adult↗
PubMed1995

Heroin bodypacking.

Drug smuggling by internal bodily concealment is a well-recognized international problem, particularly in view of the difficulty of its detection and the potential for large financial gains. This mode of transport can have serious medical complications, including drug intoxication--sometimes fatal--as well as intestinal obstruction by foreign bodies (FBs). We discuss a case of heroin 'bodypacking' (the ingestion of heroin filled condoms) with its resultant complications. The initial medical management and indications for surgery are discussed, and the relevant literature reviewed.

Adult↗
PubMed1994

Hemolytic uremic syndrome: just another case of gastroenteritis?

Hemolytic uremic syndrome (HUS), the most common cause of acute renal failure in childhood, has the potential to progress to a life-threatening illness. Its incidence in North America is increasing. Several studies have shown that Escherichia coli O157:H7 is associated with HUS. Although this pathogen was first recognized more than 10 years ago and is relatively common, many physicians are not aware of this diagnosis let alone the spectrum of illness associated with the bacteria. This case exemplifies what appears initially as gastroenteritis but, ultimately, becomes the final diagnosis of HUS. A case is presented to provide additional education to ensure the E coli O157:H7 infection is considered in the differential diagnosis of persons who present with bloody diarrhea.

Bacterial Infections↗
PubMedDate not supplied

Complications from the use of thrombolytic agents in patients with cocaine associated chest pain.

Previous investigators have noted that patients with cocaine associated chest pain frequently have abnormal electrocardiograms, including ST segment elevation, in the absence of ongoing myocardial ischemia. The effects of these nonischemic ST segment elevations have not been evaluated. We report two patients with cocaine associated chest pain and ST segment elevations who received thrombolytic agents in the absence of myocardial ischemia. Neither patient sustained a myocardial infarction, nor had clinical evidence of reperfusion. The ST segment elevations persisted after resolution of chest pain in both patients, and both of the patients experienced complications of thrombolytic therapy. One patient sustained a hemorrhagic stroke and one had minor oral-pharyngeal bleeding. Given the lack of documented efficacy, concerns about safety, and poor specificity of the electrocardiogram for myocardial ischemia in patients with cocaine associated chest pain, thrombolytic therapy should be used with caution in these patients.

Adult↗