Biomedical subjects
Publications and source records attributed to J Matthews.
Accelerated atherosclerosis is a common and recognized complication of diabetes mellitus. We have reported the fifth case of spontaneous infarction of a portion of the quadriceps muscle group in a patient with diabetes mellitus.
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Fifty-four patients meeting strict criteria for invasive pulmonary disease caused by Mycobacterium avium-intracellulare complex have been treated and followed at San Antonio State Chest Hospital during the past 15 yr. Chemotherapy with standard antituberculosis drugs was successful in effecting sputum conversion in 32 (59%) of the 54 patients. Regimens containing 2 drugs were successful in only 1 of 10 patients. If 3 or more drugs were given, 91% of those with moderately advanced cavitary disease and 64% of those with far advanced disease responded. There was no correlation between sputum conversion and use of a drug to which the organism exhibited susceptibility in vitro. No particular drug or combination of drugs was uniquely effective.
beta-Endorphin in the intermediate lobe of the pituitary gland is posttranslationally modified to produce opioid inactive peptides. Whether these are metabolites or biologically relevant products has not been known. It was found that repeated stress induces increased biosynthesis and release of beta-endorphin-like substances from the intermediate lobe of rats and that opioid-inactive N-acetylated beta-endorphin-(1-31) is selectively made and liberated. The possible role of this nonopioid product and the selective release of peptide forms are discussed.
The DGHM test for hygienic hand disinfection is based on that of Rotter et al. (1980), and compares the ability of a test agent with 60% isopropanol to reduce Escherichia coli counts on artificially contaminated fingers using 15 volunteers. The test was performed seven times--three with 10% povidone-iodine (PVP-I) scrub, three with 10% PVP-I solution and once with 5% PVP-I solution. Initial tests with PVP-I scrub ('Betadine') gave comparable results with the iso-propanol, but the latter gave an activity below that normally expected, and specified in the Austrian standard (but not in the DGHM test). A repeat test with greater attention to detail gave similar activity with the scrub, but markedly greater activity from the iso-propanol so that the PVP-I scrub failed the test. Subsequent tests with four aqueous PVP-I solutions showed that all passed the tests with activity marginally greater than that of iso-propanol. Interestingly enough, two German formulations of PVP-I solution showed almost identical activity.
A dispersal chamber (body box) technique has been used to compare bacterial dispersal from the skin of subjects carrying out a stepping test under controlled conditions while wearing four differing garment systems namely: basic underwear, cotton 'blues' (standard pyjama style jacket and trousers for men or dress for women), ankle socks, boots for men and shoes for women, mask and theatre hat; the basic set covered with a cotton gown; the basic set covered by a gown with a front made from GORE-TEX fabric in which an expanded polytetrafluoroethylene membrane is sandwiched between layers of woven or knitted polyester; the basic set covered with a fully enclosed suit of the same fabric. A slit sampler was used to measure the number of bacteria liberated in a downward current of air. Six subjects (three female and three male) were studied. Males liberated more bacteria. Covering the 'blues' with a cotton gown increased the bacterial count; a gown of the new material reduced the increase by 50%, and the suit cut the dispersal to virtually zero. Preliminary work suggests that GORE-TEX garments survive laundering better than cotton, and may be cost-effective, but are not yet as comfortable. Research is presently in progress to improve this aspect.
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In nitrate solutions, Ag+ added to the luminal side had marked effects on transmucosal conductance and potential difference (PD). Conductance increased quickly (85% within 60 s, 420% by 10 min); PD increased initially (11% within 30 s) and then fell precipitously (58% decreased within 2 min, 85% decreased by 10 min). During this period, no increase in mannitol permeability was found. These changes were essentially similar in histamine-stimulated, spontaneously secreting, and metiamide-inhibited fundic mucosae. Replacement of luminal Na+ by choline had no effect on the changes observed. Similar changes occurred also in the antrum. In SO2-4 media the increases in conductance occurred more slowly (40% within 2 min, 150% after 10 min); PD increased initially for 4-6 min and then slowly declined over 60 min to 74% of control values. After Ag+ treatment, replacement of luminal SO2-4 by nitrate led to an inversion of the PD by up to 20 mV (serosa -ve). Brief exposure of the mucosa (2 min) to Ag+ did not show any obvious damage, although surface cells were damaged following more prolonged exposures. After a 4-min treatment with Ag+, electrical and secretory parameters showed substantial recoveries. Ag+ appears to increase anion conductance; these effects appear to occur on the apical membranes of tubular and/or surface cells of the fundus and antrum.
A five-year review (1979 to 1983) of 41 patients with active tuberculosis at the time of death was performed to determine the cause of death. Twenty deaths (49 percent) were directly attributed to tuberculosis. Overwhelming tuberculous disease was the cause of death for seven patients, and among them the majority had strikingly low serum levels of albumin. Ten patients died of either massive hemoptysis or respiratory failure. Only two patients died due to progressive drug-resistant disease in an area where drug resistance is common. The majority of patients (21/41; 51 percent) died of common medical problems unrelated to tuberculosis. Eleven patients died from cardiopulmonary disease (five pulmonary emboli, one respiratory failure due to chronic obstructive pulmonary disease, two acute myocardial infarctions, and two primary dysrhythmias). Three deaths were the result of gastrointestinal bleeding, and three patients died as a result of bacterial superinfection. Our data indicate that patients still die of tuberculosis in the era of effective antituberculosis therapy. It is imperative that clinicians are aware that pulmonary emboli, arteriosclerotic heart disease, bacterial superinfection, and gastrointestinal bleeding cause approximately 50 percent of the deaths among patients who have tuberculosis and that prompt recognition and treatment of those diseases might decrease the mortality from tuberculosis.
The ability of a carbon dioxide laser to scatter debris and aerosolize bacteria from human skin was tested by collecting the aerosols liberated with glass impingers together with a slit sampler. Two sets of tests were done--one to detect dispersal of cells from treatment of rodent ulcers or warts, and the other on pieces of skin obtained from autopsy material, which had been injected with spores. With low power levels a few bacterial particles were collected, together with some whole cells, however, at levels greater than 750 W cm-2 all the cultures were sterile.
Nicorandil (SG-75) is a long acting mononitrate. A randomized, double-blind, crossover study in 10 healthy subjects has compared the haemodynamic actions of single sublingual doses of nicorandil 15, 30 and 60 mg with Isosorbide dinitrate (ISDN) 5 mg and placebo. Heart rate, blood pressure, systolic time intervals (STI) and left ventricular echocardiograms were used to assess haemodynamics over a 6 h period. Within 15 min of nicorandil administration, heart rate increased and peripheral resistance decreased (dose-dependent); the preejection period (corrected; PEPc) and the ratio of PEP to left ventricular ejection time (LVET) - PEP/LVET - were shortened by the 60 mg dose; the heart rate corrected electromechanical systole (QS2c) was almost unchanged; left ventricular end diastolic and systolic diameters (EDD and ESD) were diminished. The effects on certain parameters had not completely disappeared after 6 h. ISDN produced a similar pattern with somewhat less intense effects; although PEPc and PEP/LVET were prolonged. The effects of both drugs can be attributed to vasodilatation on both the arteriolar and venous sides. The predominant action of ISDN was to reduce preload and thereby to lengthen PEPc and PEP/LVET; in addition, it lessened afterload. Although nicorandil caused a distinct reduction in preload, as shown by the smaller EDD, the effects of afterload reduction were predominant at the high dose induced shortening of PEPc and PEP/LVET. The profile of action of nicorandil should encourage clinical testing to evaluate its ability to induce ventricular unloading.
In this intraindividual, placebo-controlled, double blind study the dynamic effects of single doses of ouabain 0.5 mg i.v. and 12 mg sublingual were compared with those of the vasodilator sublingual nitroglycerin 0.8 mg. In 12 (sublingual) and 6 (i.v.) healthy volunteers, respectively, cardiac performance was assessed for 60 min after administration, using systolic time intervals ( QS2c , PEPc, PEP/LVET), electrical impedance cardiography ( (dZ/dt)/RZ index) and echocardiography (EDD, ESD, FS). After i.v. ouabain the typical positive inotropic glycoside effects appeared (shortening of QS2c , PEPc, and PEP/LVET, increase of (dZ/dt)/RZ and FS, decrease of EDD and ESD). With nitroglycerin preload reduction diminished cardiac performance, as shown by a rise in PEPc and PEP/LVET and depression of (dZ/dt)/RZ. In addition, EDD (not significant) and ESD were somewhat reduced, FS was enhanced, and QS2c tended to shorten. Following sublingual ouabain, QS2c was unchanged, there was an increase in PEPc and PEP/LVET, a decrease in (dZ/dt)/RZ and FS, EDD was unchanged, and ESD rose. By this route the absolute magnitude of the effects was about 1/3 that of the i.v. drug action. The spectrum of effects of sublingual ouabain indicates a reduction in cardiac performance without any detectable inotropic action. The effects seem to be induced by load changes, with an indication of an increase in afterload although an additional preload reduction cannot be excluded. This dose of the drug given by the sublingual route appears, therefore, to alter cardiac function via an effect on the peripheral circulation, although the final mechanism has not yet been elucidated.(ABSTRACT TRUNCATED AT 250 WORDS)
Culture of the human melanoma cell line MeWo in the presence of 1 mM theophylline was associated with an increase in susceptibility to natural killer (NK)-mediated cytolysis. The phenomenon was detected as early as 72 hours after initiation of theophylline treatment, reaching maximum values at 3-4 weeks and remaining stable for longer than 3 months of testing, provided the cells were maintained in the presence of theophylline. The alteration in target sensitivity was selective for NK-mediated cytolysis, since other mechanisms of cell-mediated cytolysis, including antibody-dependent cell-mediated cytotoxicity and monocyte-mediated and lectin-induced cytolysis, were comparable between untreated and treated cells. The enhanced susceptibility of theophylline-treated cultures to NK lysis, as compared to NK lysis susceptibility of untreated MeWo cells, was not significantly changed by pretreatment of effector lymphocytes with interferon. Evidence for differentiation in theophylline-treated cultures was obtained. In addition, however, cytofluorometric and karyologic analysis revealed the existence of two subpopulations of differing ploidy in the MeWo line. The hypodiploid, NK-sensitive subpopulation, bearing homogeneously staining regions on two chromosomes, could be selected by growth in theophylline. Therefore, selection of subpopulations in heterogeneous tumor cell lines by chemical inducers suggests an alternative and novel mechanism for enhancement of NK sensitivity.
Of 81 adult patients with community-acquired pneumonia, bacterial infections were found in 37%, mycoplasma and viral infections in 21%, and tuberculosis in 6%; no pathogen could be identified in 46% of cases. More than one agent was identified in 12% of patients. Streptococcus pneumoniae, the most common pathogen, was found in 63%, Haemophilus influenzae in 26,7%, Staphylococcus aureus in 6,7%, and other Gram-negative organisms in 10% of patients with proven bacterial pneumonia. Most clinical and radiographic features were of little value in differentiating between different aetiological agents, but Gram-stained sputum gave a valuable early guide to therapy in 60% of cases of proven bacterial pneumonia. Blood culture was positive in 13,6% of cases. All the organisms conformed to their usual sensitivity patterns. Since Strept. pneumoniae is the predominant pathogen, penicillin should be the drug of choice in the immediate 'blind' treatment of community-acquired pneumonia.
The influence of several calcium antagonists and antiarrhythmic drugs on digoxin kinetics and actions were investigated in 36 healthy men during digoxin steady state (0.375 mg/day). The subjects were randomly assigned to three subgroups and each group received placebo (control) and two of the following regimens (doses three times a day) in a randomized sequence for 2 wk each: verapamil (80 mg) and nifedipine (10 mg), verapamil (120 mg) and gallopamil (50 mg), or propafenone (150 mg) and quinidine (250 mg). Plasma digoxin concentration (PDC) rose during the cotreatments in the sequence: gallopamil (+16%) less than propafenone (+37%) less than nifedipine (+45%) less than verapamil (almost independent of dose, +69%) less than quinidine (+118%). These increases in PDC correlated closely to decreases in renal digoxin clearances. Renal creatinine clearance was virtually unaffected. The rise of PDC resulted in increased glycoside effects, as measured by the shortening of systolic time intervals and flattening of T wave. There was a linear correlation between PDC and changes in mean corrected electromechanical systole and T wave flattening. We conclude that, in addition to quinidine, other antiarrhythmic drugs and various calcium antagonists interact kinetically with digoxin and that the increasing PDCs are cardioactive.
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