When and where to practice: social influences on the development of nut-cracking in bearded capuchins (Sapajus libidinosus).

The habitual use of tools by wild capuchin monkeys presents a unique opportunity to study the maintenance and transmission of traditions. Young capuchins spend several years interacting with nuts before cracking them efficiently with stone tools. Using a two-observer method, we quantified the magnitude of the social influences that sustain this long period of practice. During five collection periods (over 26 months), one observer recorded the behavior of 16 immature monkeys, and another observer concurrently recorded behavior of group members in the focal monkey's vicinity. The two-observer method provides a means to quantify distinct social influences. Data show that immatures match the behavior of the adults in time and especially in space. The rate of manipulation of nuts by the immatures quadrupled when others in the group cracked and ate nuts, and immatures were ten times more likely to handle nuts and 40 times more likely to strike a nut with a stone when they themselves were near the anvils. Moreover, immature monkeys were three times more likely to be near an anvil when others were cracking. We suggest a model for social influence on nut-cracking development, based on two related processes: (1) social facilitation from observing group members engaged in nut-cracking, and (2) opportunity for practice provided by the anvils, hammer stones and nut shells available on and around the anvils. Nut-cracking activities by others support learning by drawing immatures to the anvils, where extended practice can take place, and by providing materials for practice at these places.

The fourth dimension of tool use: temporally enduring artefacts aid primates learning to use tools.

All investigated cases of habitual tool use in wild chimpanzees and capuchin monkeys include youngsters encountering durable artefacts, most often in a supportive social context. We propose that enduring artefacts associated with tool use, such as previously used tools, partly processed food items and residual material from previous activity, aid non-human primates to learn to use tools, and to develop expertise in their use, thus contributing to traditional technologies in non-humans. Therefore, social contributions to tool use can be considered as situated in the three dimensions of Euclidean space, and in the fourth dimension of time. This notion expands the contribution of social context to learning a skill beyond the immediate presence of a model nearby. We provide examples supporting this hypothesis from wild bearded capuchin monkeys and chimpanzees, and suggest avenues for future research.

Effect of magnesium on restenosis after percutaneous transluminal coronary angioplasty: a clinical and angiographic evaluation in a randomized patient population. A pilot study. The Ichilov Magnesium Study Group.

Restenosis is a major clinical problem following successful percutaneous transluminal coronary angioplasty. Since magnesium has vasodilator and antithrombotic effects, this study was designed to evaluate its potential to decrease the rate of restenosis. In an open-labelled, randomized controlled study, 148 patients underwent successful coronary angioplasty. Ninety-eight patients were treated with 46-52 mmol/18-20 h intravenous magnesium sulphate (groups M1 and M2), and 49 of them continued with oral supplements of magnesium hydroxide 600 mg.day-1 (group M2). The other 50 patients served as controls (group C). Coronary angiography was performed before, immediately after and at 6 months follow-up or earlier if clinically indicated. Clinical, laboratory, ergometric and radionuclide evaluations were also carried out. One hundred and thirty-nine patients (94%) with 163 dilated segments completed the study. Intravenous magnesium was well tolerated. The cross-sectional area at the site of angioplasty increased by 3.55 +/- 2.01 mm2 in groups M1 and M2 compared with an increase of 2.90 +/- 1.63 mm2 in the control group, (P = 0.03). A trend towards a lower rate of restenosis (> 50% reduction in luminal diameter) was noticed in the magnesium groups (28/110, 25%) compared with the control group (20/53, 38%) P = 0.10. Oral administration of magnesium was well tolerated, did not have an additive effect on restenosis, but an improved clinical course was noted. It is concluded that intravenous administration of magnesium in patients undergoing coronary angioplasty is feasible and safe and that the beneficial trend of magnesium to prevent acute recoil and late (within 6 months) restenosis is encouraging and should promote further investigation in a larger patient population.

Serum lipids and restenosis after successful percutaneous transluminal coronary angioplasty. Ichilov Magnesium Study Group.

The effects of plasma lipids on the clinical and angiographic parameters of 134 patients, in whom coronary angioplasty was performed in 157 vessels, were prospectively examined. During a 6-month follow-up, restenosis was detected angiographically in 39 patients (29%; 45 vessels). None of the clinical, biochemical, or angiographic variables examined was predictive of stenosis and the tendency of a vessel to restenose was not patient-dependent but rather lesion-related. However, restenosis developed in 31 of 102 vessels (30%) in patients with high-density lipoprotein (HDL) cholesterol < or = 40 mg/dl, compared with restenosis in 10 of 55 vessels (19%) in patients with HDL cholesterol > 40 mg/dl (p = 0.092). No significant differences were observed when restenosis rates were compared in patients with total cholesterol levels > 250 mg/dl or < 250 mg/dl; no differences were seen in low-density lipoprotein (LDL) cholesterol levels when comparing patients with > 160 mg/dl and < 160 mg/dl. In 117 patients (132 vessels), complete serial blood specimens were obtained until the concluding angiography at 6 months. During follow-up, both groups (those with and without restenosis) had almost similar findings. Triglycerides decreased equally in both groups, and total cholesterol increased mildly in those who had restenosis; HDL and LDL cholesterol levels increased significantly in each group. No significant differences were observed with respect to extent of these changes between the groups. Thus, although lipid levels at the time of angioplasty and at 6 months follow-up were not found to predict the occurrence of restenosis, the association of low high-density lipoprotein levels and the tendency for restenosis should not be overlooked.

Detection of restenosis following percutaneous coronary angioplasty in single-vessel coronary artery disease: the value of clinical assessment and exercise tolerance testing.

Chest pain and submaximal exercise testing were prospectively assessed over a 6-month period, for detecting the evolution of restenosis in patients undergoing percutaneous coronary angioplasty, following either acute myocardial infarction or treatment of an anginal syndrome. Seventy-eight patients with one-vessel coronary artery disease underwent a modified treadmill exercise test at the 1-week, 3-month and 6-month follow-up after angioplasty, when a final angiogram was also performed. Forty-four patients (group A) were examined after myocardial infarction; in 34 patients (group B) angioplasty was done for incapacitating angina. Both groups showed similar results with low sensitivity and relatively moderate specificity of both chest pain and exercise tests; this was also the case for the time of restenosis to occur. It is thus concluded that the parameters examined are somewhat limited markers of restenosis following coronary angioplasty.

Epidemiology of Crohn's disease in the Jewish population of central Israel, 1970-1980.

The epidemiology of Crohn's disease (CD) during the years 1970-80 was studied in the Jewish population in a defined area of central Israel with 1.4 million inhabitants. Three hundred sixty-five patients with definite CD were identified, and a complete follow-up was obtained. The incidence of CD rose from 0.33 (per 10(5)) in 1970 to 3.10 in 1979. This rise was noted in both sexes, in all age groups, in all major Jewish community groups, and was demonstrated in three different regions of the study area. It is thought to represent a true (10-fold) increase in incidence. The mean annual incidence was 1.55/10(5). The prevalence in 1970 was 7.08/10(5), and in 1980 it was 19.47/10(5). In 1970, the age-adjusted prevalence in immigrants from Europe-America was 13.27 and in immigrants from Asia-Africa it was 1.69. In 1980, the difference between the two groups narrowed and the prevalences were 26.05 and 12.37, respectively. This decrease in differences between original migrant groups, as well as the rapid changes in incidence, point to the effect of environmental factors in the pathogenesis of CD. Population studies worldwide have demonstrated an increased incidence of CD in Jews, with marked differences among Jews in different geographic areas. This suggests the coexistence of genetic and environmental factors in the pathogenesis of the disease.

Comparison of exercise and ajmaline tests with electrophysiologic study in the Wolff-Parkinson-White syndrome.

Ajmaline test (50 mg intravenously over 1 minute) and ergometric exercise test were performed in 24 patients with the Wolff-Parkinson-White syndrome. The effects of both tests on the conduction in the accessory pathway (AP) were correlated with the anterograde effective refractory period (ERP) of the AP. Ajmaline caused transient anterograde block in the AP in 15 patients, 14 with an ERP of more than 250 ms and 1 with an ERP of 250 ms. Ajmaline failed to abolish preexcitation in 9 patients, all with ERP of the AP of 250 ms or less. Exercise testing caused anterograde block in the AP in 5 patients, in 2 during exercise (ERP of 340 and 360 ms) and in the remaining 3 patients during the recovery phase (ERP of 600, 520 and 460 ms). Of the 10 patients with an ERP of 250 ms or less, ajmaline did not abolish preexcitation in 9 and exercise did not abolish it in any of them. Of the 7 patients with an ERP of 330 ms or more, ajmaline abolished preexcitation in 7 and exercise abolished it in 5 patients. Of the 7 patients with ERP of the AP more than 250 ms but less than 330 ms, ajmaline but not exercise abolished preexcitation in all. Thus, ajmaline and exercise testing can detect patients with short and long ERPs of the AP, respectively, and the effects of ajmaline and exercise tests combined may be useful in the noninvasive assessment of various ranges of ERP of the AP.

Brucella septicemia in pregnancy.

A case of Brucella melitensis septicemia in a second-trimester pregnancy causing intrauterine fetal death and Gram-negative septic shock with diffuse intravascular coagulation is reported. The literature is reviewed. This is the first reported case of human brucellosis in association with Gram-negative sepsis and DIC during pregnancy. The importance of blood cultures and agglutinins for Brucella in febrile pregnant patients is re-emphasized.

Exercise tests in patients with severe angina pectoris: an angiographic correlation.

Graded submaximal ergometric tests were peformed on 60 patients who suffered from clinically severe angina pectoris, and the results were correlated with their coronary angiograms. The test was positive in 44, negative in 9, and undetermined in 7 patients (defined as failure to reach the target heart rate without ischemic ST changes). Among patients with positive tests, 42 (95%) had obstruction of one to three coronary vessels. Among patients with negative tests, only 3 had significant coronary disease (sensitivity 93%). While all patients suffered clinically from severe "angina pectoris," 8 (15%) had insignificant CAD, and among them 6 had a negative and 2 a false-positive exercise response (specificity 75%). Although ST depression was a good indicator of CAD, its degree did not parallel the severity of the lesions. The peak heart rate on exercise of patients with ischemic ST changes was lower than their target heart rate, suggesting that the heart rate at which ST changes occur constitutes in itself a good indicator of severity. Among the 7 patients with undetermined tests, CAD was found in 6. In these patients the absence of ST changes may be ascribed to extensive myocardial fibrosis, and the only clue to CAD resides in the negative chronotropic response to exercise. Although exercise testing does not always distinguish between normal and CAD patients, it nevertheless constitutes a valuable noninvasive technique for the detection of the high-risk patients.

"Coronary" T waves in the presence of complete left bundle-branch block: a normal variant?

The case report of a patient with an ECG pattern of intermittent left bundle-branch block, presenting inverted and symmetric ("coronary") T waves in leads V1 to V3 during periods of normal intraventricular conduction, is presented. The patient was followed up for eight years during which time no relevant symptoms appeared while extensive noninvasive investigations repeatedly failed to reveal any organic basis for the ECG changes. It is stressed that inverted, symmetric T waves in right-sided chest leads may be encountered in young, otherwise healthy subjects with intermittent left bundle-branch block during periods of normal intraventricular conduction. Knowledge of this fact is important in order to avoid iatrogenic cardiac invalidism in such cases.

Arteriosclerotic aneurysm of the coronary artery.

The findings in a patient with an angiographically proven aneurysm of the coronary artery are described. The case is reviewed in the light of 115 similar cases reported in the literature. The patient had had numerous episodes of variant angina, a feature not previously described in coronary arterial aneurysms, which may be related to embolic showers originating from the aneurysm.

Left ventricular aneurysmectomy for refractory tachyarrhythmias: report in 11 postinfarction patients.

Between January 1970 and August 1974, eleven postinfarction patients underwent left ventricular aneurysmectomy for refractory tachyarrhythmias. Ten suffered from ventricular tachycardias and one from supraventricular tachycardia. All had localized aneurysms and normal contractions of the surrounding myocardium on angiocardiography. None suffered from significant angina, congestive heart failure or papillary muscle dysfunction. The diagnosis was first suspected at fluoroscopy, the latter being in our opinion a most reliable screening method for the recognition of these cases. There was one hospital death after surgery. The remaining ten patients are now free from further arrhythmic attacks for a follow-up period between fourteen months to five and a half years. These results confirm that in some carefully selected postinfarction patients, left ventricular aneurysmectomy without concomittant aortocoronary bypass may result in the elimination of medically intractable tachyarrhythmias.

Telangiectatic fistula between the conal branch of the left coronary artery and the pulmonary trunk.

A rare case of telangiectatic communication between the conal branch of the left coronary artery and the pulmonary trunk in a 50-year-old woman is reported. Unusual features included the presence of clear-cut angina on effort, unstable auscultatory findings and a RSR' pattern in lead V1, probably related to concommitant diffuse coronary atherosclerosis. Ten previously reported cases of the condition are briefly reviewed.