ABSTRACT
The purpose of this study was to compare muscle fibre type proportions and capillary density in untrained, college-aged blacks (n = 14) and whites (n = 14). Both groups were similar in terms of peak oxygen uptake (VO2peak), measured during cycle ergometry (blacks: 42.6 +/- 4, whites: 44.3 +/- 4 ml.kg-1 min-1, mean +/- SD). Muscle samples were obtained from the quadriceps femoris (vastus lateralis) by the needle biopsy technique. Fibre type was determined by myosin ATPase stain (pH = 4.54) and capillaries were identified by amylase-periodic acid Schiff (PAS) stain. The percentage of type I, IIa, and IIb fibres in the blacks was 39.5 +/- 11.5, 40.0 +/- 8.4, and 22.8 +/- 9.8, respectively. In whites the percentage of type I, IIa, and IIb fibres was 44.9 +/- 8.5, 36.6 +/- 6.9, and 18.3 +/- 9.6, respectively. No significant differences were noted between the two racial groups for type I, IIa, or IIb fibres. Capillary density was 277 +/- 39/mm2 in the blacks compared to 289 +/- 32/mm2 in the whites. Capillary density was positively correlated to percentage of type I fibres (r = 0.497) and negatively correlated to percentage of type IIa fibres (r = -0.389), in the overall study population. These data suggest that if racial differences in fibre type do exist, such differences are small compared to the variability in this measure.
Subject(s)
Black People , Muscle, Skeletal/anatomy & histology , Muscle, Skeletal/blood supply , White People , Adolescent , Adult , Capillaries/anatomy & histology , Humans , Male , Muscle Fibers, Skeletal/cytology , Oxygen ConsumptionABSTRACT
We have studied 14 patients from a kindred with an autosomal dominant form of myotonia, with features differing from most cases of autosomal dominant or recessive myotonia congenita. All patients had painful muscle stiffness that was provoked by fasting and oral potassium administration and was relieved by carbohydrate-containing foods. Muscle biopsies showed the presence of type 1, 2A, and 2B fibers, as opposed to the absence of type 2B fibers seen in some patients with myotonia congenita. Acetazolamide was dramatically effective in alleviating myotonia in all patients and was more effective than other antimyotonic agents.
Subject(s)
Acetazolamide/therapeutic use , Myotonia Congenita/drug therapy , Adult , Female , Glucose , Humans , Male , Muscles/metabolism , Muscles/pathology , Myotonia Congenita/genetics , Myotonia Congenita/pathology , Pedigree , PotassiumABSTRACT
To assess the factors responsible for oropharyngeal colonization with gram-negative bacilli among elderly persons in institutions, we performed a cross-sectional survey of 407 volunteers, 65 years of age and older, who had not received antimicrobials in the previous four weeks. Colonization increased with level of care: from 9 per cent in independent residents of apartments to 60 per cent in patients on an acute hospital ward (P less than 0.0001). Klebsiella species was found in 41 per cent of those with colonization, Escherichia coli in 24 per cent and enterobacter species in 14 per cent. There was no association between numbers of normal flora and numbers of gram-negative bacilli. Associated with colonization were bladder incontinence, deteriorating or terminal clinical status, inability to walk or perform activities of daily living and incapacitation due to neoplastic, respiratory and cardiac disease (P less than 0.05). Multivariate analysis indicated that respiratory disease and being bedridden contributed most to colonization.