Caffeine-induced arousal modulates somatomotor and autonomic differential classical conditioning in humans

Two experiments (n = 48 and n = 45) investigated the effects of caffeine-induced arousal on differential classical conditioning of eyeblink (experiment 1) and autonomic (experiment 2) responses. Three groups of human subjects received double-blind administration of 0, 2, and 4 mg/kg oral caffeine (groups 0, 2, and 4, respectively). Twenty minutes after caffeine administration, a differential classical conditioning procedure was in effect. Physiological and subjective arousal was assessed by readings of blood pressure, skin conductance level, and a questionnaire, administered before caffeine administration, and after the conditioning procedure. The results showed increased indexes of physiological arousal in groups 2 and 4. In experiment 1, differential classical eyeblink conditioning was observed in groups 0 and 4, whereas no differential conditioning was seen in group 2. In experiment 2, differential classical conditioning was seen in group 0, whereas caffeine-induced arousal masked acquisition of conditioned skin conductance responses in group 4. This group displayed increased resistance to extinction compared to the other groups. Group 2, which had an intermediate level of arousal, did not display differential conditioning in either experiment. Taken together, the results indicate that small increases in arousal may be detrimental to learning, and larger increases in arousal may reverse this effect. Received: 10 March 1997/Final version: 13 June 1997     

A computer algorithm for triple radionuclide subtraction studies applied for preoperative localization of enlarged parathyroid glands

This paper presents a computer algorithm for triple radionuclide subtraction studies and its application to preoperative localization of enlarged parathyroid glands. In the clinical examination procedure, ¹³¹I-toluidine blue was used as the principal radionuclide, ^99mTcO₄ and ^113mIn were used to obtain additional images of the thyroid and the blood distribution respectively. A scintillation camera with a pinhole collimator and connected to a digital data aquisition system was used to record the images. Subtraction of uniform background, thyroid and blood contributions to the principal image is done automatically in the computer program. The results from a clinical study is used to illustrate the method.     

Long-term follow-up of patients with peripheral arterial obliterations treated with arterial surgery.

This paper presents the long-term results of 221 thrombendarterectomy operations during the period 1955-61, and of 86 femoro-popliteal venous bypass operations during the period 1961-64. The indication for surgery was in the majority of the patients disabling claudication. When pain at rest or ulceration was present, arterial reconstruction was performed even when the outlook for a lasting result was poor. Preoperatively a major amputation seemed inevitable in 31 limbs. Thirteen of these are considered to have been saved by the operation. After aortoiliac thrombendarterectomy patent arteries were found in 80% of the extremities after one year and in 48% after 10 years. Forty-five per cent of the extremities were patent on re-examination or remained patent until death. After fermoro-popliteal thrombendarterectomy, 61% of the arteries were patent after one year and 26% after 10 years. Thirty-nine per cent of the arteries were patent on re-examination or remained patent until death. After femoro-popliteal venous bypass, 88% of the grafts were patent after one year and 58% after 5 years. Forty-nine per cent of the grafts were patent on re-examination or remained patent until death. The postoperative mortality was small (4.4% after aortoiliac surgery and 2.0% after femoro-popliteal surgery), and mostly caused by widespread atherosclerosis in other parts of the arterial system. On re-examination 8 to 16 years after the operation, 63% of the patient were dead. Almost 50% of the deaths were caused by coronary heart disease, 17% by cerebrovascular catastrophes, and 13% by other manifestations of atherosclerotic disease. The results are discussed, and it is concluded that long-term results after vascular surgery may be favourable. Peripheral atherosclerosis is, however, a local manifestation of a generalized disease. The indications for reconstructive arterial surgery should therefore be relatively restricted.     

Plasma concentration of folate as a biomarker for the intake of fruit and vegetables: the Hordaland Homocysteine Study

BACKGROUND: Nutritional biomarkers may be used to assess dietary exposure without the errors commonly associated with self-reported dietary data. OBJECTIVE: The objective was to examine the association between plasma folate and intake of folate, fruit, and vegetables in a large cohort of healthy adults consuming foods that had not been fortified with folic acid. DESIGN: The present study population included 5533 middle-aged (47-49 y) and old (71-74 y) subjects from the Hordaland Homocysteine Study. The participants completed a food-frequency questionnaire and provided blood samples for chemical analyses. RESULTS: We observed a significant difference in plasma concentrations of folate across increasing quartiles of fruit, vegetable, and orange juice consumption. The difference in plasma folate between the highest and lowest quartiles was 1.97 (95% CI: 1.86, 2.07) nmol/L for fruit intake, 1.79 (95% CI: 1.69, 1.89) nmol/L for vegetable intake, and 2.69 (95% CI: 2.51, 2.87) nmol/L for orange juice intake. A significant inverse relation was observed across increasing quartiles of milk and bread intakes. The difference between the highest and lowest quartiles was -1.03 (95% CI: -1.13, -0.92) nmol/L for milk and -1.60 (95% CI: -1.69, -1.50) nmol/L for bread. CONCLUSION: Plasma folate concentration may be a useful biomarker for the intake of fruit and vegetables in populations consuming unfortified food products. The association can be attenuated by and should be corrected for individual intake of folic acid supplements.     

Variability in dust exposure in a cement factory in Tanzania

Dust exposure levels were studied in a cement factory in Dar es Salaam, Tanzania, as part of an epidemiological study assessing chronic respiratory health effects. One hundred and twenty personal 'total' dust samples were collected from 80 randomly selected workers from eight a priori occupational groups (OGs) based on work areas using a 37 mm Millipore sampler. The between-group, within-group and within-worker variances were determined to assess the contrast in exposure level between the OGs and to estimate the attenuation and standard error of the theoretical exposure-response slope. Using mixed-effect model estimates, the probability of overexposure relative to the occupational exposure limit (OEL) was assessed for each OG. The geometric means of total dust exposure were higher in the cranes (38.64 mg m(-3)), packing (21.30 mg m(-3)) and crusher (13.48 mg m(-3)) than in the cement mill (3.23 mg m(-3)), kiln (2.87 mg m(-3)), raw mill (1.85 mg m(-3)), maintenance (1.16 mg m(-3)) and administration (0.29 mg m(-3)). The a priori grouping scheme seems to be an efficient scheme because of the high contrast in exposure level between the OGs (0.78) and minimal attenuation of the theoretical exposure-response slope (1.0%). When using the reduced mixed-effect model, the probabilities of overexposure () relative to the OEL of 10 mg m(-3) for total cement dust were higher in the crane (96%), packing (88%) and crusher (73%) than in the cement mill (16%), kiln (14%), raw mill (5%), maintenance (2%) and administration (0.01%).     

Bodily pain and associated mental distress among immigrant adolescents

Abstract Objective The aim of this study was to describe differences among immigrant groups in bodily pain, and analyze its association with mental distress. Method A population-based cross-sectional study was carried out involving tenth grade pupils in Oslo. Of the 7,343 pupils that participated, one-quarter were first- or second-generation immigrants. The Hopkins Symptom Checklist-10 was used to measure mental distress. All information on pain and mental distress was self-reported. Results Girls reported more bodily pain from all types of pain. Headache was the most prevalent pain site across gender and immigrant groups. Strong associations between mental distress and number of pain sites were found for all immigrant groups. Neck and shoulder pain yielded the highest odds ratio (OR) for mental distress among the majority of the immigrant groups. The Sub-Saharan African group had the highest adjusted OR for mental distress [OR=9.8 (1.1–82.7)] when reporting three or more pain sites, and the Indian Subcontinent the lowest [OR=4.0 (1.8–8.8)]. Conclusion The differences in number and types of pain were small, though significant between the different immigrant groups. Adolescents from Sub-Saharan Africa seem to react with more mental distress to bodily pain than adolescents emigrating from the Indian Subcontinent.     

Hematological parameters and cobalamin status in infants born to smoking mothers

Hematological parameters, serum cobalamin and folate levels, and the concentrations of the functional markers plasma methylmalonic acid and total homocysteine were determined in 173 newborns and 46 infants at 6 weeks to see whether maternal smoking influences the hematological parameters and the vitamin status of the newborn. At birth, there was a strong inverse correlation between the number of cigarettes smoked per day during pregnancy and red blood cell count (r = -0.56, p = 0.001) and hemoglobin level (r = -0.52, p = 0.003) in the newborns. Neonates born to smoking mothers had lower red blood cell counts and lower hemoglobin and serum cobalamin levels as compared with infants born to nonsmoking mothers. At 6 weeks, maternal smoking significantly predicted the methylmalonic acid and total homocysteine levels, suggesting an influence from smoking on the cobalamin function in these infants.