Sex-specific effects for body mass index in the new Norwegian twin panel

Sex-specific effects for body mass index (BMI) were explored in a newly established, population-based Norwegian twin panel. The sample includes 5,864 individuals, aged 18–25 years, who responded to a questionnaire containing items for zygosity classification, height, weight, health, health-related behaviors, well-being, and demographic information. Among the 2,570 intact pairs who returned the questionnaire there were 416 identical (MZ) male pairs, 387 fraternal (DZ) male pairs, 528 MZ female pairs, 443 DZ female pairs, and 796 unlike-sexed pairs. Alternate sets of models testing for either sex-specific genetic or environmental parameters were evaluated using structural equation analysis. Results from the most parsimonious model indicated that the genes contributing to variation in BMI are not identical for men and women; rather, some genetic effects were shared by the sexes and some were unique to each sex. Total variation in BMI could be explained by sex-specific additive genetic effects, as well as genetic and non-shared environmental effects common to men and women. Estimates of heritability were .708 for men and .789 for women, and the male-female genetic correlation was 0.622. The series of models specifying sex-specific shared environment also fit the data and suggests that shared environmental factors may be important for males but not for females. The findings raise questions concerning the relationship between sex-specific effects for BMI and sex differences in health outcomes. ©1995 Wiley-Liss, Inc.     

Cluster headache: phospholipid metabolism in polymorphonuclear cells

Our group has previously reported significant changes in the incorporation of precursors into glycerophospholipids, particularly phosphatidylserine, in polymorphonuclear cells obtained from the peripheral blood of cluster headache patients, when compared with controls. The potential of these results led to further work using both the previous methodology and a modified isolation technique to obtain polymorphonuclear cells in as pure a state as possible. Neither the new results obtained using the original technique, nor the results with high purity polymorphonuclear cells from controls and cluster headache patients, confirm the marked changes in precursor uptake into glycerophospholipids originally reported.     

Concept and practice of international health in the Takemi program

The Takemi Program in International Health was established at the Harvard School of Public Health in 1983 as a research and advanced training program for midcareer health professionals concerned with the allocation of resources for health, especially in developing countries. This essay describes the origins of the Takemi Program and presents seven principles that underlie the concept and practice of international health in the Takemi Program. The principles are: research emphasis, policy orientation, interdisciplinary perspective, mutual respect, individual freedom, community spirit, and individual capacity building. The broader implications of these principles are suggested for current efforts to redefine the concept of international health.     

Phonatory reaction times of rheumatoid arthritic and normal females

This study examined the degree to which rheumatoid arthritis affects a speaker's ability to accomplish rapid vocal fold adjustments. The phonatory initiation, phonatory termination, and manual reaction times of 14 rheumatoid arthritic (RA) and 14 normal (NL) speakers were compared during a morning and an afternoon session. In addition, electroglottographic (EGG) measures (0 Hz-10 kHz bandwidth and 30 Hz-10 kHz bandwidth) allowed us to explore the components of each subject's reaction times. For two speech reaction-time tasks, temporal measures that reflected primarily mechanical adjustments of the vocal folds were significantly longer in the RA group than in the NL group. The two groups also differed significantly on manual response time, phonatory initiation time, and medial movement initiation time. Neither group displayed evidence of laryngeal morning stiffness.     

Interactions between serotonin and substance P in the spinal regulation of nociception

Interactions between 5-hydroxytryptamine (5-HT) and substance P (SP) in the mouse spinal cord were investigated using the tail-flick test and the behavioral response evoked by intrathecal (i.th.) SP or i.th. 5-HT. I.th. injection of 5-HT (20 μg) or the 5-HT₁ receptor agonists(+)-8-hydroxy-2-(di-n-propylamino)tetralin ((+)-8-OH-DPAT) (20 μg) or 5-methoxy-3(1,2,3,6-tetrahydropyridine-4-yl)-1H-indole (RU 24969) (20 μg) markedly inhibited the tail-flick reflex. The effect of these compounds was reduced when SP (5 μg) was given i.th. 55 min, or 55 and 45 min before the agonists. The tail-flick latencies recorded 5 min before injection of a 5-HT agonist were similar in animals treated with SP or vehicle. The changes in the tail-flick test were not due to changes in tail skin temperature since only minimal differences in the skin temperature were recorded between the groups injected with SP or vehicle. I.th. injection of SP (10 ng) or 5-HT (2 μg) produced a similar behavioral response consisting of biting, licking and scratching of the caudal part of the body, indicative of nociceptive stimulation. The responses both to i.th. SP and 5-HT were reduced after i.th. application of SP receptor antagonist [d-Arg¹,d-Trp^7,9,Leu¹¹]-SP (Spantide) (5 μg), as well as 5 min after i.th. injection of the 5-HT receptor antagonist metergoline (4 μg). The data may indicate functional interactions between SP and 5-HT in the mouse spinal cord, which may take place in neurons involved in the processing of nociception.     

Mixed organic brain syndrome as a manifestation of systemic mastocytosis

Systemic mastocytosis is a disease characterized by an excessive accumulation of mast cells, and associated with skin lesions, flushing, diarrhea, tachycardia, and psychiatric manifestations. In order to define more clearly the psychiatric manifestations, ten patients with this disorder underwent unstructured psychiatric interviews and a battery of psychologic testing. Both revealed a pattern of cognitive and affective changes in the majority of these patients, best categorized as an atypical or mixed organic brain syndrome. The cognitive changes consisted of diminished attention and memory, and the affective changes of anger, irritability, and, to a lesser extent, depression. These manifestations fluctuated with the level of disease activity, and appeared in some cases to respond to histamine antagonists and disodium cromoglycate, medications used to control the excessive mast cell activity. It is important for psychiatrists to be aware that mental status changes can represent psychiatric manifestations of mastocytosis, a readily treatable medical disorder.     

Contractile properties of in situ perfused skeletal muscles from rats with congestive heart failure

We hypothesized that in congestive heart failure (CHF) slow-twitch but not fast-twitch muscles exhibit decreased fatigue resistance in the sense of accelerated reduction of muscle force during activity. Experiments were carried out on anaesthetized rats 6 weeks after induction of myocardial infarction or a sham operation (Sham). Animals with left ventricular end-diastolic pressure (LVEDP) > 15 mmHg under anaesthesia were selected for the CHF group. There was no muscle atrophy in CHF. Force generation by in situ perfused soleus (Sol) or extensor digitorum longus (EDL) muscles was recorded during stimulation (trains at 5 Hz for 6 s (Sol) or 10 Hz for 1.5 s (EDL) at 10 or 2.5 s intervals, respectively) for 1 h in Sol and 10 min in EDL at 37 °C. Initial force was almost the same in Sol from CHF and Sham rats, but relaxation was slower in CHF. Relaxation times (95–5 % of peak force) were 177 ± 55 and 131 ± 44 ms in CHF and Sham, respectively, following the first stimulation train. After 2 min of stimulation the muscles transiently became slower and maximum relaxation times were 264 ± 71 and 220 ± 45 ms in CHF and Sham, respectively (   P < 0.05  ). After 60 min they recovered to 204 ± 60 and 122 ± 55 ms in CHF and Sham, respectively (   P < 0.05  ). In CHF but not in Sham rats the force of contraction of Sol declined from the second to the sixtieth minute to 70 % of peak force. The EDL of both CHF and Sham fatigued to 24–28 % of initial force, but no differences in contractility pattern were detected. Thus, slow-twitch muscle is severely affected in CHF by slower than normal relaxation and significantly reduced fatigue resistance, which may explain the sensation of both muscle stiffness and fatigue in CHF patients.     

Technical fixes and other problems in saving lives in the world's poorest countries

4 types of impediments are suggested to the 3 kinds of technology that now promise great advances for health conditions in poor countries, i.e., the classical public health measures, the miracle drugs and machines of modern medicine, and the emerging processes of the new biology. These barriers -- the inherent limitations of technology, economic constraints on implementation, social and cultural obstacles to adoption, and the political processes of the health system -- are reviewed in an effort to clarify the role of technology in saving lives in the world's poorest countries. To start, it is necessary to recognize the inherent limitations of technical innovations in reducing mortality rates. A new drug, such as praziquantel, may be effective in humans in combatting the parasite responsible for schistosomiasis, yet as long as water supplies and snails remain contaminated and poor sanitation and water use habits persist, the cycle of disease transmission also may persist, meaning people can be reinfected. Disease control is affected critically by the interaction of society with the environment. Thus, the effectiveness of certain privately produced drugs in controlling disease depends on implementing the appropriate public health measures. Technology also has shown limited capability to eradicate diseases. The 1st and only successful case of intentional disease elimination is smallpox. Regarding economics, only 0.95% of the gross national product (GNP) in 22 low-income countries in sub-Saharan Africa went for the government's health budget. Government expenditures on health are limited. Poor countries traditionally have depended heavily on foreign assistance to provide health supplies, and recent cutbacks in US foreign aid have cut into the health programs of poor countries. The lack of a strong social infrastructure presents a major obstacle to the application of health technology in poor nations. Social behavior and cultural patterns also can interfere with the appropriate use of technology to improve health. The political forces within a country affect the role of technology in improving health conditions, and the politics of foreign assistance works to shape the health system of poor nations. Politics interferes most directly with health delivery in cases of social instability and open war. In sum, new technology is only 1 element in resolving the health problems of a society. Social as well as technical research needs to be conducted in the poor countries and in the world academies.     

Nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction in patients with mitral valvular disease

Using the rapid-response thermistor pulmonary artery catheter and transoesophageal echocardiography, this study examined the effects of 100 per cent oxygen, 70 per cent nitrous oxide/30 per cent oxygen, and 70 per cent nitrogen/30 per cent oxygen on the pulmonary circulation and ventricular function in ten patients with pulmonary hypertension. In comparison with baseline measurements, nitrous oxide administration resulted in small but statistically significant (P less than 0.05) changes in mean arterial pressure (76 +/- 14 to 67 +/- 12), mean pulmonary arterial pressure (37 +/- 14 to 33 +/- 13 mmHg), and cardiac output (3.7 +/- 1.4 to 3.2 +/- 1.1 L.min-1). Seventy per cent nitrogen resulted in no significant changes from baseline. The repeat 100 per cent oxygen measurements were nearly identical to the nitrous oxide measurements. It is concluded that nitrous oxide does not exacerbate pulmonary hypertension or ventricular dysfunction during high-dose fentanyl anaesthesia in patients with mitral valvular disease.