Recently ultrasound has been found to be extremely useful in detecting intracardiac thrombi as well as intracranial hemorrhages in neonates. The principal criterion used for clinical diagnosis of thrombus has been an increase in the echogenicity of clotted blood. However, echogenicity is a rather nonspecific and qualitative description of tissue ultrasonic properties. A rise in echogenicity could be the result of an increase in ultrasonic backscatter, or a decrease in attenuation, or a combination of both. In order to ascertain the mechanism responsible for the clinically observed increase in echogenicity and thus put the technique on a firm foundation, we have measured serially the ultrasonic velocity, attenuation and backscatter in human blood up to 24 hours following the onset of coagulation. Preliminary results show that all three ultrasonic properties increase during this time period. At 24 hours following clotting, the mean rises in velocity, attenuation and backscatter are 3.36 +/- 0.35 X 10(3) cm/sec, 2.3 +/- 0.22 db/cm and 18.5 +/- 1.2 dB per unit volume of blood (at 7.5 MHz and a temperature of 23 degrees C), respectively. These results indicate that the increase in echogenicity of a thrombus is due to a substantial increase in ultrasonic backscatter, which is moderated to a certain extent by the accompanied increase in attenuation.

Acoustics↗

PubMedDate not supplied

Who is interpreting nuclear cardiology studies in the United States, and what are the requirements for privileges? A national survey of institutional policies from 80 major medical centers.

BACKGROUND: This survey was conducted to determine the guidelines used by major medical centers in the United States for obtaining hospital privileges to interpret nuclear cardiology studies. The American College of Cardiology (ACC) and the American Society of Nuclear Cardiology (ASNC) have established guidelines to help maintain an adequate level of proficiency in the practice of nuclear cardiology. These guidelines were published only recently, and many hospitals have adopted different processes to obtain these privileges. It is likely that a marked difference among institutions exists. METHODS AND RESULTS: The survey was conducted predominantly by mailings with additional telephone communications if more information was needed. Chiefs of cardiovascular medicine sections were contacted to provide information concerning the policy of granting nuclear cardiology privileges at his or her institution. The responses were tabulated in four categories and the responders were asked to comment on whether they agreed or disagreed with their own university's policy. Of 80 responses (68%) from 121 institutions, cardiologists were involved in reading these studies in 62 (78%) and radiologists were the sole interpreters in 18 (22%). ACC or ASNC guidelines were strictly followed at 48 sites (60%). Eight (10%) and 6 (8%) of these institutions mandated a minimum requirement of, respectively, 12 and 6 months of additional training in nuclear cardiology. Ten (13%) of the cardiologists surveyed disagreed with their own institution's policies, primarily noting that the ACC and ASNC guidelines were more appropriate. CONCLUSION: The recently established ACC/ASNC guidelines clearly have had an impact on the practice of attaining privileges in nuclear cardiology and are the most commonly quoted criteria used by institutions in the United States to assess competence in nuclear cardiology.

Cardiology↗

PubMedDate not supplied

The safety of adenosine pharmacologic stress testing in patients with first-degree atrioventricular block in the presence and absence of atrioventricular blocking medications.

BACKGROUND: Pharmacologic stress testing in conjunction with radionuclide myocardial perfusion imaging may be used in the diagnosis of coronary artery disease and risk assessment. Adenosine can cause atrioventricular nodal (AV) block during infusion. In this study, we evaluated whether patients with baseline first-degree AV block could safely undergo adenosine stress testing. METHODS AND RESULTS: We evaluated the frequency of second- and third-degree AV block in patients with baseline first-degree AV block during adenosine stress testing, in the presence and absence of AV blocking medications (digitalis, beta-blockers, diltiazem, verapamil). Six hundred consecutive patients underwent pharmacologic stress myocardial perfusion imaging with adenosine infusion at 140 microg/kg/min for 6 minutes. A total of 43 patients (7.16%) had baseline first-degree AV block (PR interval > 200 msec), and 557 patients had a baseline PR interval < 200 msec. Twenty-one of the 43 patients (48.8 %) had further prolongation of PR interval > 240 msec, compared with 58 of 557 patients (10.4%) in the control group (P < .0001). In 16 of the 43 patients (37.3 %), second-degree AV block developed, compared with 45 of 557 patients (8.0 %) in the control group (P < .0001). In 6 of the 43 patients (13.9%), third-degree AV block developed, compared with 6 of 557 patients (1.0%) in the control group (P < .0001). All types of AV block were short duration and were not associated with any specific symptoms. None of these episodes required specific treatment. The presence of AV blocking medications (digitalis, beta-blockers, diltiazem, verapamil) did not increase the incidence of AV block during adenosine infusion. CONCLUSION: In patients with baseline PR interval of more than 200 msec, the frequency of second- and third-degree AV block during adenosine stress testing was significantly higher than in patients with a normal baseline PR interval. AV blocking medications did not increase the incidence of second- and third-degree AV block during adenosine stress testing. We conclude that it is safe to perform adenosine pharmacologic stress testing in patients with baseline PR prolongation.

Adenosine↗

PubMedDate not supplied

Epidemiology of genital papillomaviruses and cervical cancer.

Cervical cancer is an extremely common disease. Its natural history has been well described, and individual risk factors have been defined. It is clear from the epidemiologic evidence that cervical cancer has a multifactorial etiology involving infection with sexually transmitted agents such as genital papillomaviruses and cofactors such as pregnancy, smoking, use of hormonal contraceptives, and diet. The evidence implicating papillomavirus as an etiologic agent of cervical cancer has come from a variety of observational laboratory studies. Genital papillomaviruses induce dysplastic lesions. Most invasive cervical cancers contain papillomavirus DNA, as do cell lines derived from cervical cancers. Viral DNA, appears to be integrated into cellular DNA, and integration involves highly conserved, transcriptionally active regions of the viral DNA.

Age Factors↗

PubMedDate not supplied

Prevalence of sexually transmitted diseases in high-risk women in the Republic of Panama.

This study enrolled 1,032 sexually active women attending social hygiene clinics in Panama City; clinic attendance is mandatory for women employed in houses of prostitution, bars, and cabarets. Women were interviewed, and endocervical specimens were obtained for culture of Neisseria gonorrhoeae, Chlamydia trachomatis, herpes simplex virus, and cytomegalovirus. Four occupational groups attended the social hygiene clinics: prostitutes, bar girls denying prostitution, cabaret entertainers, and streetwalkers detained by the police. Prevalence of sexually transmitted disease, nationality, race, contraceptive method, and self-medication varied significantly by occupation; 31% of streetwalkers had gonorrhea as did 10% of prostitutes, 5% of bar girls, and 3% of cabaret entertainers. Rates of positive serologic tests for syphilis followed the same trend: 23% in streetwalkers, 7% in prostitutes, and 3% in nonprostitutes. Rates of chlamydial infection were significantly higher in cabaret entertainers (8%) than in any other occupational group (2%). Cytomegalovirus and herpes simplex virus infections were uncommon and were found in 5% and 1% of the women, respectively. Prevalence of N. gonorrhoeae varied with self-medication and years of "professional" experience. Only one of 160 N. gonorrhoeae isolates was resistant to penicillin and also beta-lactamase-positive.

Contraception Behavior↗

PubMedDate not supplied

The frequency of atrioventricular block during adenosine stress testing in young, middle-aged, young-old, and old-old adults.

The frequency of atrioventricular (AV) block was evaluated in 600 consecutive patients of different age groups referred for pharmacologic stress testing. Adenosine was infused at 140 mg/kg/min for a total of 6 minutes in conjunction with radionuclide myocardial perfusion imaging. Seventy-five patients (12.5%) were young adults (< 49 years old), 214 (35.6%) were middle-aged (50-65 years), 195 (32.6%) were young-old (66-75 years), and 116 patients (19.3%) were old-old (over 75 years). The frequencies of first-degree AV block in young adults, middle-aged, young-old, old-old, and all ages were 14.6%, 9.3%, 14.3%, 17.24%, and 13.16%, respectively. The frequencies of second-degree AV block were 14.65%, 7.0%, 8.7%, 15.5%, and 10.1%, respectively. The frequencies of third-degree AV block were 2.66%, 2.33%, 1.0%, 2.58%, and 2.0%, respectively. Comparison of the incidence of the three types of AV block for each age group vs. all patients showed no statistically significant difference (p > 0.08). All types of AV block were of short duration, were well tolerated, and did not require discontinuation of the adenosine infusion or specific treatment. This study confirms the safety of adenosine stress testing in all age groups for evaluation of coronary artery disease and risk assessment.

Adenosine↗

PubMedDate not supplied

Epidemiology of epilepsy in Guaymi Indians from Bocas del Toro Province, Republic of Panama.

This cross-sectional study was conducted to describe the epidemiology of epilepsy in Guaymi Indians residing in Changuinola, a small town on Panama's Caribbean coast near Costa Rica. We randomly selected households and attempted to enroll all residents aged less than or equal to 1 year; 337 eligible subjects agreed to participate (93% response rate). We administered a standard neurologic disease screening examination to all subjects and, if any abnormality was found, we administered a standard neurologic evaluation. We detected 19 cases of active epilepsy; the mean age at onset was 12 years, and generalized tonic-clonic seizures were the most common diagnosis (10 of 19, 53%). The prevalence of active epilepsy among Caribbean coastal Guaymi (57/1000) is considerably greater than that in lower class Panama City populations (22/1000) or in other parts of the world. To identify risk factors for epilepsy, we collected epidemiologic data and serum (for Cysticercus antibody) from subjects with active epilepsy and from 44 age/sex-matched controls. Significantly more cases (47%) than controls (6%) had other family members with epilepsy (relative risk, RR = 14); 44% of cases and 13% of controls reported a history of febrile seizures during childhood (RR = 6).

Adolescent↗

PubMedDate not supplied

Reversible cardiomyopathy due to selenium deficiency.

Selenium is an essential trace element and a component of glutathione peroxidase, an enzyme that may help to prevent oxidative damage to cells. Selenium deficiency has been linked to the development of Keshan disease, a dilated congestive cardiomyopathy occurring primarily in children living in rural China. Sporadic cases have been reported in the United States in individuals with poor nutritional intake, mostly in individuals on long-term home parenteral nutrition. This report describes a young black woman with Crohn's disease in whom a congestive cardiomyopathy developed and was subsequently reversed following administration of selenium.

Adult↗