Diagnosis in Prader-Willi syndrome.

Thirty one patients with the putative diagnosis of Prader-Willi syndrome were reassessed clinically and by DNA analysis. Eleven patients were judged not to have Prader-Willi syndrome and 20 to have the condition. This was confirmed by DNA analysis in all but one case. The diagnosis of Prader-Willi syndrome, especially in early infancy, should be made with caution unless confirmed by molecular genetic studies.     

Vietnamese refugees in Victoria, B.C.: An overview of immigrant and refugee health care in a medium-sized Canadian urban centre

This paper examines the manner in which Vietnamese refugees acces the healthcare system in Victoria, British Columbia. A major theme of this study was the identification of barriers to health care access and provision as perceived by refugees and health care providers, as well as areas of overlap between the two sets of perceptions. The study was based on interview protocols developed with key informants followed by structured samples of 20 Vietnamese and 20 health care workers. The major issue identified by both groups was problematic interpretation of patient symptoms and health care provider recommendations. Lack of health care worker understanding of traditional remedies for common ailments was also identified as a barrier to health care access and utilization. The special problems of unemployment, depression, surviving torture and getting assistance are all made more difficult for refugees living in a smaller urban centre which lacks sufficiently large ethnic populations to assist in service provision. A number of suggestions are made which might ameliorate the difficulties of refugees living in smaller communities. These include municipally based client advocates and special translation training for existing hospital staff.     

Nonimmune hydrops caused by massive fetomaternal hemorrhage and treated by intravascular transfusion.

Fetal hydrops at 26 weeks' gestation was diagnosed following a massive fetomaternal hemorrhage. Fetal intravascular transfusion was performed, and the hydrops completely resolved within 72 hours. The fetus required one more transfusion at 27 weeks' gestation. A subsequent percutaneous umbilical blood sampling at 30 weeks' gestation demonstrated a normal fetal hematocrit. A vaginal delivery at term resulted in a normal newborn. Massive fetomaternal hemorrhage is a well-known cause of nonimmune hydrops and may occur spontaneously in an otherwise normal pregnancy. Confirmation by percutaneous umbilical blood sampling and treatment by intravascular transfusion is recommended when massive fetomaternal hemorrhage causes hydrops in preterm gestations.     

重睑术

重睑术是美国最流行的美容外科手术，每年的手术人数达500000-600000之多。洛杉矶Jules Stein眼科研究所的Baylis医师说，1年做10例的医师可以与1年做200例其他医师一样熟练。Baylis医师估计，人群的25％企望做重险术。     

Familial dyslipidemic hypertension. Evidence from 58 Utah families for a syndrome present in approximately 12% of patients with essential hypertension

Population-based sibships with essential hypertension diagnosed before the age of 60 years are being screened in Utah to find two or more hypertensive siblings with the same biochemical abnormality as a clue to an inherited cause for their specific type of hypertension. Among 131 hypertensive subjects in 58 sibships, concordant abnormalities in fasting serum lipid concentrations were observed in two or more siblings in 48% of the sibships. After adjusting for effects of antihypertensive medications, abnormal values reported in only 10% of the Lipid Research Clinics data were observed in 30% of patients for serum triglycerides, 19% for serum low-density lipoprotein cholesterol, and 39% for high-density lipoprotein cholesterol. More than one lipid level was abnormal in almost all concordant sibships, suggesting an association between hypertension and a syndrome of mixed lipid abnormalities, probably familial combined hyperlipidemia (renamed "familial combined dyslipidemia" because of common low high-density lipoprotein cholesterol levels). We conclude that familial dyslipidemic hypertension may be a specific syndrome with lipid abnormalities more severe than blood pressure elevations.     

Activation of skinned arthropod muscle fibres by Ca2+ and Sr2+

Summary Mechanically skinned skeletal muscle fibres of three crustaceans (barnacle, crayfish and crab) and two insects (cockroach and cricket) were activated in Ca²⁺- and Sr²⁺-buffered solutions of different concentrations and the isometric force response was determined. The maximum force response induced by Sr²⁺ (P ₀ ^Sr ) was only 0–10% of that induced by Ca²⁺ (P ₀ ^Ca ) in all crustacean muscles, but approached 90% in insects. Experiments on barnacle muscle fibres activated simultaneously by Ca²⁺ and Sr²⁺ suggested that Sr²⁺ competes with Ca²⁺ for binding onto the regulatory sites without, however, being able to turn all of them on as efficiently as Ca²⁺. Interestingly, the ratioP ₀ ^Sr /P ₀ ^Ca and the sensitivity for both Sr²⁺ and Ca²⁺ increased substantially after 4–6 h following the dissection of the animals in most intact decapod muscle fibres and after 24 h in most barnacle muscle fibres. The steepness of the activation curves for both Ca²⁺ and Sr²⁺ was similar for each muscle regardless of the age of the fibre and implied that more than 2 Ca²⁺ (2 Sr²⁺) were involved in the activation process of each muscle.A Ca²⁺-induced Ca²⁺ release mechanism of physiological importance was found to operate in all arthropod muscle fibres investigated.     

Theory and observation of spontaneous oscillatory contractions in skeletal myofibrils

Summary At low levels of activation, an isometrically-held myofibrillar preparation on the descending limb may exhibit persistent oscillations of period 1–6 s in tension and sarcomere lengths. We propose a sarcomeric theory of spontaneous oscillatory contraction, based on the phenomena of force creep and delayed length activation. The time delay leads to oscillations and controls their period. A computer model using these ideas simulates spontaneous oscillatory contraction for fixed-end fibres only if isometric tension capacity varies slightly along the fibre. The form of this inhomogeneity controls a diversity of spontaneous oscillatory contraction behaviour: the tension waveform can vary from large and sinusoidal to small-amplitude pulses or chaotic behaviour, and these variations are observed in slow-twitch soleus fibres from the same animal (rat). The model predicts that oscillatory and quiescent regions coexist in the fibre, with large-amplitude sawtooth waveforms in sarcomere length in the former as observed. It can also generate travelling-wave structures, similar to those found by the Tokyo group, in oscillating regions when there is a spatial gradient in isometric tension capacity. Phase discontinuities in sarcomere length occur near the oscillatory-quiescent boundary. Predictions for the Ca²⁺ concentrations and sarcomere lengths in which spontaneous oscillatory contraction occurs and for differences in the spontaneous oscillatory contraction frequencies of fast-and slow-twitch fibres compare well with experiment. Spontaneous oscillatory contraction is also predicted under isotonic conditions.