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Biomedical subjects

L Samuels

Publications and source records attributed to L Samuels.

8 recordsLinked to original sources
PubMed1988

Safety and diagnostic accuracy of dipyridamole-thallium imaging in the elderly.

The noninvasive diagnosis of coronary artery disease in the elderly can occasionally be difficult. Intravenous dipyridamole-thallium imaging is a potentially useful diagnostic test to determine presence and severity of coronary disease; however, the safety of the procedure has not been determined in an older population. The side effect profile and frequency of severe ischemic responses after 0.56 mg/kg of intravenous dipyridamole were compared in 101 patients greater than or equal to 70 years old and 236 patients less than 70 years old. There were no side effects in 64% and 62% of patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). Among the 337 patients tested, there were no complications of myocardial infarction or death. The most common cardiac side effect was chest pain, which occurred in 21 (21%) of the 101 patients aged greater than or equal to 70 years and in 64 (27%) of the 236 patients less than 70 years (p = NS). Aminophylline was required to reverse cardiac or noncardiac side effects in 15 (15%) and 36 (15%) of the patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). A severe ischemic response occurred in 2% and 2.5% of patients greater than or equal to 70 and less than 70 years old, respectively (p = NS). The sensitivity of intravenous dipyridamole-thallium imaging for obstructive coronary artery disease was 86% (25 of 29) and 83% (68 of 82) in older and younger patients, respectively (p = NS); the specificity was 75% (6 of 8) and 70% (16 of 23), respectively (p = NS). Thus, intravenous dipyridamole-thallium imaging is a safe noninvasive method for assessment of older patients with obstructive coronary disease; its side effect profile and diagnostic accuracy are similar to those seen in younger patients. The technique is associated with severe ischemic responses in only a small minority of patients.

Adult↗
PubMed1979

Sex differences in concordance rates for schizophrenia in twins.

In response to my discussion of sex differences in concordance rates for schizophrenia in twins, Lewine (1979) noted that male schizophrenics are hospitalized earlier than females. He questioned whether females had been followed through the risk period. To clarify, I calculated the age at followup of discordant twins in three studies. In Gottesman and Shields' (1972) study, the majority of both male and female co-twins were still under the age of 45. In contrast, all but a few of Kringlen's (1967a, 1967b, 1968) and Fischer's (1973) co-twins were 45 or over. Their findings support the conclusion that recent twin studies show no significant sex differences in concordance.

Diseases in Twins↗
PubMed1978

Sex differences in concordance rates for schizophrenia: finding or artifact?

The literature on schizophrenia has reported a trend toward higher concordance rates for females in both monozygotic and dizygotic same-sexed twins. The validity of this finding is open to question. Rosenthal (1961 and 1962) pointed out that females are more likely than males to become inhabitants of chronic wards. Most of the studies reporting a sex difference used resident hospital populations. Gottesman and Shields (1972) noted that the sex difference disappeared when samples were based upon consecutive admissions. Sex differences have vanished in recent studies both as a result of changing research methods and the changing role of women in society.

Diseases in Twins↗