Isolation and characterization of muscle membranes using surface-specific labels

Membranes were purified from rat muscle by a differential centrifugation method that avoids the use of salt extraction or incubations at elevated temperature. Three populations of membrane-limited vesicles were defined having average densities of 1.112 (fraction I), 1.141 (fraction II), and 1.158 (fraction III) g/ml in a continuous sucrose gradient. Lactoperoxidase-catalyzed iodination of intact muscle prior to isolation of membranes resulted in highest specific activity in fraction I, although all fractions could be equally labeled after isolation. 125I-Labeled wheat germ agglutinin incubated at low concentration with intact muscle preferentially labeled fraction I. Parallel studies on previously isolated fractions indicated that fraction I also contained the highest concentration of potential receptors for wheat germ agglutinin. In experiments on whole muscle, concanavalin A bound predominantly to sarcolemma with slight variable binding to T-tubular and nuclear membrane but no binding to sarcoplasmic reticulum or mitochondria. Parallel binding studies with isolated membrane fragments indicated heavy binding of concanavalin A by membranes in fraction I with scattered binding in fractions II and III. Na+K+Mg2+ ATPase was specifically enriched in fraction I but was also present in fraction II in a proportion similar to 125I labeling. Ca2+ ATPase was most active in fraction II but present in significant levels in fraction I. It is concluded from these and other data that fraction I contains predominantly sarcolemma membrane, while T-tubular membrane may represent a significant component of fraction II. Ca2+ ATPase activity in fraction I is intrinsic to the sarcolemma.

Cephalexin compared to ampicillin treatment of otitis media

Cephalexin was compared to ampicillin for the treatment of otitis media in a randomized study. Bacteriologic diagnosis was sought by needle tympanocentesis in 179 children. No overall statistically significant differences were noted between the two groups; however, 20 patients who received cephalexin had a poor response to therapy whereas only five recipients of ampicillin responded poorly. A significant difference (P less than .05) between the two regimens was noted when Hemophilus influenzae was recovered. Fifty per cent of the children with H. influenzae otitis media who were treated with cephalexin responded poorly; no patients receiving ampicillin had a poor response. Our data suggest that the use of cephalexin monohydrate is not warranted for treatment of otitis media due to H. influenzae even when the isolate proves sensitive to this drug in vitro. In selected patients with otitis media caused by Staphylococcus aureus which is resistant to penicillin, cephalexin may provide effective treatment.

A model study of facial injury caused by impact while wearing an ophthalmic frame

Damage to facial tissue caused by an ophthalmic frame when there is impact to the face was studied by means of a paraffin-covered mannequin head. Under mild conditions of impact it was easily observed that metal frames and metal components do more tissue damage than is done by a zylframe. A series of the commonly dispensed frames was compared for facial injury potential caused by impact to the face.

Kinetic processes in Escherichia coli membranes and cells. A laser photolysis study using derivatives of pyrene

Pyrene and several derivatives of pyrene are used to investigate photo-induced kinetic processes in whole cells and membranes extracted from Escherichia coli. A mutant of E. coli was used which, under appropriate growth conditions, produced a complete or incomplete lipopolysaccharide in the outer membrane. The pyrene derivatives used were: pyrene sulfonic acid, pyrene butyric acid and the ester of pyrene butyric acid and 10-hydroxydecanoic acid. The pyrene chromophore was excited by the ultraviolet pulse from a Q switch, frequency-doubled, ruby laser. The lifetimes of the pyrene fluorescence in the presence of the quenchers O2, thallous ion (T1+), I-and CH3NO2 were measured and tabulated as second order rate constants. For the most part the quenching rate constants were much lower than the corresponding values observed in simple nonviscous solution, e.g. ethanol. This is interpreted as being due to the location of the probe within the membrane. The membrane inhibits the movement of the quenchers to the excited state. Cell membranes containing complete lipopolysaccharide showed significantly lower quenching rates for the probes pyrene and pyrene sulfonic acid than cell membranes with incomplete lipopolysaccharide. From an amalysis of the kinetic data it is suggested that pyrene and pyrene sulfonic acid are located near and under lipopolysaccharide and close to membrane proteins. On the other hand, no effect of lipopolysaccharide composition was observed for the probes pyrene butyric acid and pyrene butyroyl decanoic acid. This may suggest that these probes are located primarily in the lipid part of the membrane. A simple model for the outer membrane of E. coli is suggested that accounts for the observed laser-induced kinetic processes.

Design for obtaining the half-axial projection

A device for obtaining the half-axial projection complementing single plane cine equipment is described. The design enables a single technician to raise and lower the patient's upper half of the body between 0 degrees and 20 degrees of longitudinal deviation from the rotating cradle, set between 0 degrees and 70 degrees of horizontal deviation. Materials cost less than $100 and can be assembled by personnel in most hospitals.

Aldosterone-Induced Membrane Phospholipid Fatty Acid Metabolism in the Toad Urinary Bladder

Aldosterone action in the isolated toad urinary bladder has been studied by incubation of the tissue with several specifically labeled lipogenic precursors. Within 30 min after hormone addition phospholipid synthesis is stimulated; the metabolism of oleic acid is particularly enhanced. Additionally, during this time interval a phospholipid deacylation-reacylation cycle is stimulated by aldosterone.

Optimizing cinefilm

A system for improving the quality of cinefilm and for maintaining quality control is described. Objective criteria for contrast, resolution, and grain structure were established to measure the effects of varying X-ray dose, f-stop, development temperature, and selection of film and developer. We found that all variables nust be adjusted to maximize the viewing quality and that similar denisty curves can be achieved, independently of the choice of film and developer.

Congenital coronary artery aneurysms

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In vivo sampling of cardiac triglyceride from dogs during ethanol infusion

The feasibility of procuring and analyzing cardiac tissue for triglyceride in vivo was tested in anesthetized dogs. Measurements of triglycerides in samples obtained in vitro confirmed: reproducibility of triplicate analyses of the glycerideglycerol moiety of tissue triglyceride (SEM +/- 2.1%), homogeneity in and between ventricles (SEM +/- 1.8%), and agreement between right endocardial triglyceride and left myocardial triglyceride (difference not significant). Seven dogs received ethanol, 15-30 mg/kg/min, and five dogs received glucose or 0.85% NaCl for 2 hr. Cardiac output and filling pressure were measured from the left ventricle and tissue was taken from the right ventricle with a biopsy catheter before and during infusions. Three to four samples were obtained from each dog; the average weight was 14.4 mg and two to three biopsies were required for each sample. In the ethanol group, triglyceride increased after 15 min and continued to rise; the final triglyceride concentration correlated with the infusion rate. In the glucose-saline group, in vivo triglyceride concentration did not change and did not differ from postmortem triglyceride. Cardiac function declined in the ethanol group and was unaffected in the controls. Thus, multiple in vivo measurements of cardiac lipid are practical and safe and show that ethanol infusions cause early and progressive accumulation of triglyceride in heart muscle.

Abnormal homicide in Hong Kong

The different classifications of homicide used make comparative studies difficult. For our purposes we will sub-divide homicide as follows: (i) ‘Abnormal homicide’, comprising (a) ‘murder-suicide’ in which the murder suspect commits suicide, and (b) ‘abnormal murder’, comprising cases where (i) the murder suspect is mentally ill, or (ii) the court returns a verdict of manslaughter by reason of diminished responsibility. (2) ‘Normal homicide’, a term we will use synonymously with ‘normal murder’, i.e. murder committed by the mentally normal.

Hormonal control of the renal conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol

Isolated renal tubules from vitamin D-deficient chicks catalyse the in vitro conversion of 25-hydroxycholecalciferol to 1,25-dihydroxycholecalciferol. This conversion is stimulated by 5 x 10(-10) M bovine parathyroid hormone, or by 10(-6) M cyclic AMP. It is inhibited by 10(-9) M porcine calcitonin. It is concluded that these hormonal controls of the synthesis of the renal hormone 1,25-dihydroxycholecalciferol are of particular physiological significance in coordinating the activities of the various organs involved in extracellular calcium homeostasis.

Diastolic mitral regurgitation. Haemodynamic and angiographic correlation

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