Can Simple Doppler Measurements Estimate Interatrial Conduction Time?

COZMA, D., et al.: Can Simple Doppler Measurements Estimate Interatrial Conduction Time? Prolongation of the interatrial conduction time (ia-CT) is considered an important factor in the pathophysiology of atrial fibrillation (AF) and as a criterion to perform multisite atrial pacing. Measurement of ia-CT requires an electrophysiologic study. The aim of this study was to compare echocardiographic with electrophysiologic measurements to determine if they are correlated. Methods and Results: The study included 32 consecutive patients who underwent electrophysiologic studies. We measured ia-CT between the high right atrium and the distal coronary sinus. In all patients we measured P wave duration, left atrial diameter and area, and ia-CT by Doppler echocardiography was measured as the difference in time intervals between the QRS onset and the tricuspid A wave, and the QRS onset and the mitral A wave (DT). Ia-CT was statistically correlated with DT  (r = 0.79, P < 0.0001)  , but not with P wave duration or left atrial dimensions. Conclusions: Measurement DT may be reliable to estimate ia-CT without invasive procedure. Accordingly, DT could be used as a simple selection criterion when considering patients for atrial resynchronization therapy. (PACE 2003; 26[Pt. II]:436–439)     

Structure, distribution and innervation of muscle spindles in avian fast and slow skeletal muscle

Muscle spindles in 2 synergistic avian skeletal muscles, the anterior (ALD) and posterior (PLD) latissimus dorsi, were studied by light and electron microscopy to determine whether morphological or quantitative differences existed between these sensory receptors. Differences were found in the density, distribution and location of muscle spindles in the 2 muscles. They also differed with respect to the morphology of their capsules and intracapsular components. The slow ALD possessed muscle spindles which were evenly distributed throughout the muscle, whereas in the fast PLD they were mainly concentrated around the single nerve entry point into the muscle. The muscle spindle index (number of spindles per gram wet muscle weight) in the ALD was more than double that of its fast-twitch PLD counterpart (130.5±2.0 vs 55.4±2.0 respectively, n=6). The number of intrafusal fibres per spindle ranged from 1 to 8 in the ALD and 2 to 9 in the PLD, and their diameters varied from 5.0 to 16.0 μm and 4.5 to 18.5 μm, respectively. Large diameter intrafusal fibres were more frequently encountered in spindles of the PLD. Unique to the ALD was the presence of monofibre muscle spindles (12.7% of total spindles observed in ALD) which contained a solitary intrafusal fibre. In muscle spindles of both the ALD and PLD, sensory nerve endings terminated in a spiral fashion on the intrafusal fibres in their equatorial regions. Motor innervation was restricted to either juxtaequatorial or polar regions of the intrafusal fibres. Outer capsule components were extensive in polar and juxtaequatorial regions of ALD spindles, whereas inner capsule cells of PLD spindles were more numerous in juxtaequatorial and equatorial regions. Overall, muscle spindles of the PLD exhibited greater complexity with respect to the number of intrafusal fibres per spindle, range of intrafusal fibre diameters and development of their inner capsules. It is postulated that the differences in muscle spindle density and structure observed in this study reflect the function of the muscles in which they reside.     

Body Composition in 995 Acutely ill or Chronically ill Patients at Hospital Admission: A controlled population Study

Objective To determine if fat-free mass and fat mass in acutely ill and chronically ill patients differed from healthy controls at hospital admission and if prevalence of malnutrition differed by body mass index (BMI) or fat-free mass percentile.Subjects/Setting 995 consecutive patients 15 to 100 years of age admitted to the hospital were measured in the hospital admission center and compared with 995 healthy age- and height-matched subjectsDesign Cross-sectional study. Fat-free mass, fat mass, and percentage fat mass were determined by 50 kHz bioelectrical impedance analysis. Prevalence of malnutrition was determined by BMI <20 kg/m² or fat-free mass in the 10th percentile.Statistical Analysis Analysis of variance was used to examine differences between acutely ill and chronically ill patients and controls and between age groups.Results Fat-free mass was significantly lower in patients than controls (P<.05), and the difference with age in fat-free mass in patients was greater than the age-related difference in the controls. A higher percentage fat mass was found in spite of lower BMI in chronically ill patients older than 55 years. Among participants, 25% of acutely ill and 37.3% of chronically ill patients fell below fat-free mass in the 10th percentile, compared with 15.6% of acutely ill and 18.9% of chronically ill patients falling below BMI ≤20 kg/m².Applications/Conclusion Weight and BMI do not evaluate body compartments and therefore do not reveal if weight changes result in loss of fat-free mass or gain in fat mass. In spite of minimal differences in BMI between patients and controls, we found that fat-free mass was lower and fat mass was higher in acutely ill and chronically ill patients than controls. The objective measurement of body composition, as part of a comprehensive nutritional assessment, helps to identify subjects who have low fat-free mass or high fat mass. J Am Diet Assoc. 2002;102:944-948,953-955.     

Episiotomy and third-degree tears

Summary. The relation of episiotomy to third-degree perineal tears was investigated in 21 273 singleton deliveries. The incidence of episiotomy was 28.4% ( n =6041). Third-degree tears occurred in 14% (85) of the deliveries with episiotomy and in 0.9% (132) of the deliveries without episiotomy ( P <0.01). To avoid the effect of confounding factors, we analysed a sub-sample that included only vertex presentations with spontaneous occipitoanterior vaginal deliveries. After stratification for birthweight and parity, no relation between episiotomy and third-degree tear was found.     

Renal Osteodystrophy in Children Treated with 1,25-Dihydroxy-Cholecalciferol [1,25-(OH)2D3]: Histologic Bone Studies

ABSTRACT. Eleven uremic children with osteodystrophy aged 3 to 17 years were studied during administration of l, 25-(OH)₂D, for periods up to 21 months. Nine children presented with pure hyperparathyroidism, one with osteomalacia and one with mixed bone disease. Bone biopsies were performed before initiation of therapy and after 6 to 21 months of treatment following double tetracycline labeling. Skeletal lesions were improved but not cured in 5 of 9 children with hyperparathyroidism. In three instances lesions remained unchanged and worsened in one. No significant change was observed in the child with osteomalacia. Moderate improvement was noted in the patient with mixed bone disease. The propensity to develop hypercalcemia was the major factor associated with treatment failure since it precluded administration of adequate amounts of medication. Therapy with l, 25-(OH)₂D₃ was associated with a spectacular improvement in growth velocity in two of six children under age twelve.     

Evaluation of an Azo and Two Anthraquinone Dyes for Allergic Potential

Two dye mixtures and the individual component dyes were evaluatedfor the potential to induce contact or pulmonary hypersensitivity.These dye mixtures were suspect because of anecdotal reportsof both pulmonary and contact hypersensitivity in assembly workers,and because the component dyes were structurally related todyes known to be contact sensitizers. One mixture consistedof disperse blue 3 (DB3) and disperse red 11 (DR11), which areanthraquinones, and the other mixture contained DR11 and solventred 1 (SR1), an azo dye. Contact hypersensitivity was examinedusing the local lymph node assay (LLNA) and a modified mouseear swelling test (MEST). Both the MEST and the LLNA indicatedthat SR1 has weak contact-sensitizing potential. None of theother individual dye compounds or the two mixtures were identifiedas contact sensitizers by either method. To evaluate the mixturesas potential pulmonary allergens, guinea pigs were repeatedlyexposed by inhalation (300 mg/m³ 6 hr/day) 5 days/week, for1 week. Weekly exposures were repeated three times with 2 weeksof nonexposure time in between. Guinea pigs were then challengedthrough the jugular vein using a dye-dimethylsulfoxide mixture.During the challenge, breathing mechanics (dynamic complianceand resistance) were measured in mechanically ventilated animals.Changes in these measurements, indicative of bronchoconstriction,were not observed in animals exposed to either dye mixture,nor were antibodies detected in the sera of exposed animalsusing individual dye-specific enzyme-linked immunosorbent assays.In conclusion, two methods indicate that SR1 may have contact-sensitizingpotential. There was no indication of contact-sensitizing potentialfor either DB3 or DR11 and no evidence that any of the dyescaused pulmonary hypersensitivity.     

Heparin attenuates bleomycin but not silica-induced pulmonary fibrosis in mice: possible relationship with involvement of myofibroblasts in bleomycin, and fibroblasts in silica-induced fibrosis

Pulmonary fibrosis was elicited in mice or rats by the intra-tracheal instillation of bleomycin or silica. Daily injections of heparin significantly reduced the collagen deposition in bleomycin, but not in silica, injected mice, as evaluated by the lung hydroxyproline content on day 15 after instillation. Heparin also reduced the bleomycin-induced morbidity and mortality. Study of the broncho-alveolar lavage fluid (BAL) detected no significant change in the number of leucocytes or the amount of protein in heparin treated mice. Histologies of bleomycin instilled mice suggested that heparin did reduce the alveolar remodelling but not the alveolitis, evidenced by leucocytic infiltration. As detected by electron microscopy (EM), bleomycin increased the number of leucocytes and platelets within the alveolar capillaries but this was not significantly reduced by heparin. The phenotype of the interstitial cell involved in these two types of pulmonary fibrosis was investigated by immunohistochemistry and EM. While in bleomycin injected animals the interstitial cells had the phenotype of an actin (α-actin in the rat) and lipid containing interstitial cell, with a poorly developed RE, in silica injected animals in contrast, the interstitial cells were without cytoplasmic actin or lipid but with a markedly developed endoplasmic reticulum (ER). Thus bleomycin and silica induced the growth of two different types of interstitial cells, the myofibroblast and the regular fibroblast, which might be a reason why heparin selectively inhibits bleomycin but not silica-induced fibrosis.