Cytochrome b-245 of neutrophils is also present in human monocytes, macrophages and eosinophils.

A cytochrome b with a midpoint oxidation-reduction potential of -245mV (cytochrome b-245) that is a major component of the microbicidal oxidase system of human neutrophil leucocytes has been identified in human eosinophils, monocytes and macrophages at concentrations similar to that found in human neutrophils. It was absent from a variety of other cells. This cytochrome is present in phagocytic leucocytes and probably plays an important part in the specialized activities of these cells.     

CROSS-SECTIONAL ECHOCARDIOGRAPHIC FINDINGS IN VEGETATIVE AORTIC VALVE ENDOCARDITIS

M-mode echocardiograms of two patients with bacterial endocarditis of approximately 4 months' duration showed dense echoes in the area of the aortic valve. In one patient, who had no prior abnormal cardiac findings, the echoes were clearly suggestive of valvular vegetations. The second patient, however, was known to have had aortic valve disease and a systolic murmur for more than a decade; therefore, dense echoes arising from the aortic valve also could have resulted from valvular calcification. In both patients, cross-sectional echocardiography provided important information. In the first patient, retrograde cardiac catheterization was prevented by large and highly mobile masses attached to the aortic cusps that prolapsed into the left ventricular outflow tract during diastole. Aortic valve replacement without further hemodynamic evaluation was recommended. In the second patient, whose blood cultures remained negative after the acute phase of his illness had been treated, cross-sectional echocardiography showed large vegetations on the aortic valve. Intraoperative findings confirmed the echocardiographic interpretation in each case.     

ACOUSTIC CHANGES IN NORMALLY FUNCTIONING MITRAL VALVE PROSTHESES: ECHO-PHONOCARDIOGRAPHIC OBSERVATIONS

This study confirms previous findings of variability in the intensity of the closing click (CC) as a consequence of premature valve closure. Such alterations have been described as a normal phenomenon in several prosthetic valve models. Combined echo-phonocardiography is of particular value in evaluating prosthetic valve function in patients with unusual and confusing auscultatory changes.     

IDENTIFICATION OF LARGE LEFT ATRIAL THROMBUS BY CROSS-SECTIONAL AND M-MODE ECHOCARDIOGRAPHY

In addition to a typical pattern indicative of mitral stenosis, the M-mode echo-cardiogram of a patient with mitral valve disease revealed a broad band of dense echoes within an enlarged left atrial cavity that was suggestive of an intraatrial thrombus. Subsequent cross-sectional echocardiography demonstrated a globular cluster of echoes inside the left atrial cavity, thus corroborating our interpretation of the M-mode recording. When open mitral commissurotomy was performed, a large, partially calcified thrombus was found protruding from the posterior wall and left atrial appendage into the atrial cavity. Postoperative M-mode and cross-sectional echocardiography did not show the previously noted abnormal echoes within the left atrium.     

Effect in vivo of beta-adrenergic stimulation, angiotensin II, dibutyryl cyclic AMP, and theophylline on tonin concentration in rat saliva and submaxillary gland.

Tonin (an enzyme present in rat submaxillary gland and saliva) has previously been shown to be able, unlike renin and reninlike substances, to release angiotensin II either directly by acting on an appropriate substrate or from angiotensin I. The administration of a beta-adrenergic drug, isoproterenol, produces a rise of tonin concentration in saliva without affecting its concentration in the submaxillary gland. Prior administration of a beta blocker, propranolol, partially prevents this effect. The administration of theophylline increases the tonin concentration in both saliva and the submaxillary gland, whereas dibutyryl cyclic AMP increases tonin concentration in the former. These results suggest that beta-adrenergic stimulation enhances both tonin release into the saliva and tonin synthesis in the submaxillary gland, and that these effects might be mediated by cyclic AMP. Infusion of angiotensin II blocked the stimulatory effect of isoproterenol on salivary tonin. 1Sar-8Ile-angiotensin II is both a weak antagonist of angiotensin II in this respect and a strong agonist in terms of blocking the effect of isoproterenol another role mirrored in other physiological mechanisms of derivatives of angiotensin II.     

Lactose-proton symport by purified lac carrier protein

The lac carrier protein of Escherichia coli was purified by an improved procedure and its activity assayed by a rapid filter method. Following reconstitution of the carrier by octyl glucoside dilution, proteoliposomes were concentrated by filtration on a microporous filter. Lactose accumulation by adsorbed or entrapped proteoliposomes is driven by an artificially imposed pH gradient (interior alkaline), by a membrane potential (interior negative), or by a combination of both forces. Activity is almost completely abolished by the protonophore carbonyl cyanide m-chlorophenylhydrazone or by the competitive inhibitor thiodigalactoside. Addition of lactose to proteoliposomes under appropriate conditions results in alkalinization of the external medium. This effect is not observed with liposomes devoid of lac carrier or in the presence of proton conducting agents. The results provide a strong indication that the lac gamma gene product is the only protein in the cytoplasmic membrane of Escherichia coli required for lactose-proton symport.     

Direct measurement of lactose/proton symport in Escherichia coli membrane vesicles: further evidence for the involvement of histidine residue(s)

Addition of lactose to Escherichia coli ML 308-225 membrane vesicles under nonenergized conditions induces transient alkalinization of the medium, and the initial rate of proton influx is stimulated by valinomycin and abolished by nigericin or carbonyl cyanide m-chlorophenylhydrazone. A functional lac y gene product is absolutely required as the effect is not observed in ML 308-225 vesicles treated with N-ethylmaleimide nor with vesicles from uninduced Escherichia coli ML 30. Furthermore, the magnitude of the phenomenon is enhanced about 3-fold in vesicles from Escherichia coli T206, which contain amplified levels of the lac carrier protein. Kinetic parameters for lactose-induced proton influx are the same as those determined for lactose-facilitated diffusion, and quantitative comparison of the initial rates of the two fluxes indicates that the stoichiometry between protons and lactose is 1:1. Treatment of ML 308-225 vesicles with diethyl pyrocarbonate causes inactivation of lactose-induced proton influx. Remarkably, however, treatment with the histidine reagent enhances the rate of lactose-facilitated diffusion in a manner suggesting that the altered lac carrier catalyzes lactose influx without the symport of protons. The results are consistent with the hypothesis that acylation of a histidyl residue(s) in the lac carrier protein dissociates lactose influx from proton influx and indicate that this residue(s) play(s) an important role in the pathway of proton translocation.     

Immobilization of Lipase from Mucor Miehei Onto Poly (Ethylene) Based Graft Copolymers

Lipase from Mucor miehei was immobilized covalently onto hydrolyzed poly(ethylene)-g.co-hydroxyethyl methacrylate (PE-HEMA). This hydrolysis of the copolymer was achieved using 0.1 M NaOH over different periods of time, under controlled conditions. The graft copolymers and their hydrolyzed equivalents were characterized by scanning electron microscopy (SEM) and by differential scanning calorimetry analysis (DSC). Water sorption studies were undertaken to provide a measure of relative hydrophobicity of the samples.

The lipase immobilization reaction was studied in order to assess the effects of controlling various important parameters. These include the nature of the buffering medium, the time over which the immobilization was allowed to occur, the concentration of the activating and coupling agent used (CMC) and the concentration of enzyme employed during attempts at effective immobilization. The immobilized lipase was used in the hydrolysis of triolein (glycerol trioleate). From this study, the apparent K_M, the optimum pH for hydrolysis and the optimum temperature for hydrolysis were revealed.

The suitability of hydrolyzed poly(ethylene)-g.co-HEMA as a support in the immobilization of lipase was assessed by determination of the amount of lipase coupled to the support and by assessment of the retention of activity of the immobilized lipase after its exposure to the immobilization reagents, procedure and conditions.