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Biomedical subjects

L B Guze

Publications and source records attributed to L B Guze.

At least 55 records · Page 3Linked to original sources
PubMed1979

Quantitation of serum tobramycin concentration using high-pressure liquid chromatography.

A high-pressure liquid chromatography method for the quantitative determination of tobramycin in serum is described. The antibiotic was separated from serum by chromatography on a silica gel column. The adsorbed antibiotic was derivatized with o-phthalaldehyde, and then eluted with isopropanol. The derivatized tobramycin was separated by reverse-phase chromatography and quantitated by fluorometry. Serum concentrations as low as 0.5 microgram/ml could be accurately measured. A linear response for serum samples containing tobramycin ranging from 0 to 20 microgram/ml was obtained. Other antibiotics, including various aminoglycosides, did not interfere with the tobramycin assay. Comparison with a standard microbiologic assay gave a correlation coefficient of 0.99. This chemical assay is sensitive, precise, specific, and can be performed in 30 minutes.

Animals↗
PubMed1979

Circulating immune complexes in experimental streptococcal endocarditis: a monitor of therapeutic efficacy.

An important problem in the management of infective endocarditis has been the delineation of laboratory procedures that are sensitive, reliable indicators of therapeutic efficacy. Because circulating, complement-containing immune complexes of the IgG type (CICs) have been demonstrated in most humans with infective endocarditis, serum CIC levels during the natural course of the infection and in response to penicillin therapy were studied in 42 rabbits with right-sided endocarditis due to Streptococcus salivarius. A significant rise in the level of CICs in both 21 control rabbits and 21 treated rabbits was observed after induction but before treatment of infective endocarditis (P less than 0.01). In the 17 successfully treated rabbits, CIC levels fell sharply during the first week of therapy and remained at preinduction levels thereafter (P less than 0.005). In contrast, CIC values did not change significantly either in control animals or in the four treated animals with refractory endocarditis, although in the latter animals, serum bactericidal titers remained less than or equal to 1:32. These findings suggest that serial measurements of CIC levels during antimicrobial therapy of infective endocarditis may aid in monitoring therapeutic efficacy.

Animals↗
PubMed1979

A nosocomial outbreak of infections due to multiply resistant Proteus mirabilis: role of intestinal colonization as a major reservoir.

An outbreak of nosocomial infections involving an unusual strain of multiply resistant Proteus mirabilis (phage type 8888) occurred in 15 patients, 14 of whom were in the surgical intensive care unit at that time. No common source of infection was identified, and person-to-person transmission was the most likely mode of spread. Case-control analysis indicated a significantly increased risk infection related to length of hospital stay (P less than 0.005), number of operations (P less than 0.005), proximity to another case (P less than 0.01), number of antibiotics received (P less than 0.02), and use of a respirator (P less than 0.01). Only the number of operations (P less than 0.01) and proximity to another case (P less than 0.05) remained significant risk factors when related parameters were controlled by multivariate analysis. Thirteen of 14 patients prospectively cultured were colonized by the epidemic organism in the intestinal tract, while rectal carriage preceded infection by the same strain in at least four patients. These data suggest that intestinal colonization may have been an important reservoir for this outbreak, and the findings may explain the unduly prolonged course of intrahospital spread as well as the difficulty encountered in the eradication and control of the outbreak.

Cross Infection↗
PubMed1979

Comparative in vitro activity of five cephalosporins against Lactobacilli.

Of five parenteral cephalosporins tested against 43 lactobacilli, cephaloridine, cefazolin, and cefamandole were the most active inhibitory and bactericidal agents. Timed-kill analysis revealed a slow bactericidal effect, with significant declines in mean minimal bactericidal concentration values at 48 h versus 24 h.

Cephalosporins↗
PubMed1979

Experimental hematogenous Candida endophthalmitis: diagnostic approaches.

Anterior chamber aspiration and vitreous aspiration were evaluated as diagnostic procedures for establishing a specific microbiological diagnosis in the rabbit model of hematogenous Candida endophthalmitis. Vitreous aspiration was the most successful procedure, confirming the diagnosis of hematogenous Candida endophthalmitis in 62% of eyes with documented intraocular infection. When animals with only the most severe clinical endophthalmitis were considered, vitreous aspiration confirmed the diagnosis in 89% of eyes evaluated. Vitreous aspiration correlated well with the extent of clinical endophthalmitis, as well as with postmortem, whole-vitreous cultures. Gram staining of the aspirate was additive to culture results in confirming the diagnosis. Anterior chamber aspiration was positive in only 1 of 58 eyes evaluated (1.7%). Additionally, muscle biospy was evaluated in this study as a tool for establishing a microbiological diagnosis in the rabbit model of disseminated candidiasis. Only 2 of 131 biospy specimens contained detectable Candida. Although vitreous aspiration may be associated with ocular complications, in certain clinical settings this procedure may be valuable in establishing the definitive microbiological diagnosis of hematogenous Candida endophthalmitis.

Animals↗
PubMed1979

Effect of renal physicochemical milieu on stimulation of human lymphocytes by phytohemagglutinin.

The effect of changes in certain physicochemical parameters, analogous to those occurring in the kidney, on stimulation of normal human lymphocytes by phytohemagglutinin was studied. Increase in osmolality by sucrose or urea, and increases in concentration of sodium, potassium and calcium all significantly inhibited stimulation while magnesium did not. Lowering pH to 6.8 and 6.5 inhibited stimulation. Raising the pH to 8.0 had no effect bu at pH 8.4 stimulation was decreased. The effect was largely but not entirely due to decrease in viability.

Calcium↗
PubMed1978

Cytomegalovirus proteins: II. Polypeptide composition of cytomegalovirus complement-fixing antigen.

Complement-fixing (CF) antigen, prepared from cytomegalovirus (CMV)-infected cells and solubilized by urea and Tween-20, was fractionated on agarose gel columns. Its molecular weight was 1.5--5 X 10(7) daltons, and it contained 5 major peptides with molecular weights from 60,000--90,000 daltons. The peptide with a molecular weight of 70,000 daltons which was present in the solubilized CF antigen was absent in a soluble fraction from infected cells without CF activity and may be, therefore, important in this respect. The antigens present in the CF antigen did not elicit neutralizing antibody.

Antigens, Viral↗
PubMed1978

Lactobacillemia--report of nine cases. Important clinical and therapeutic considerations.

Serious infections due to lactobacilli have been rarely cited. We report our findings in nine recent patients with lactobacillemia. In the combined literature and current experience, endocarditis and sepsis from localized suppuration were the most common clinical syndromes, most frequently arising from prior oropharyngeal infections. Lactobacillus endocarditis showed a predilection for left-sided cardiac involvement (100 per cent) and systemic arterial embolization (55 per cent). The nine clinical isolates were tested for minimal inhibitory and bactericidal concentrations (MICs and MBCs) against five drugs with broad gram-positive spectrums; of note, these organisms demonstrated a high incidence of both unachievable MBCs (64 per cent) and widely disparate (greater than 100 fold) MIC:MBC ratios (38 per cent). This is in accord with observations in Lactobacillus endocarditis of poor in vivo clinical response despite "appropriate" regimens and achievable MICs of the organisms. Bactericidal synergistic studies on two endocarditis isolates indicated that the penicillins plus aminoglycosides may be potentially useful in the treatment of deep-seated Lactobacillus infections when single antimicrobials fail to achieve a cure.

Adult↗
PubMed1978

Acute interstitial nephritis due to methicillin.

Fourteen patients are described with a syndrome of methicillin-induced interstitial nephritis. In all patients severe renal dysfunction developed with an average peak serum creatinine of 8 mg/100 ml. An increased total peripheral eosinophil count was found in all patients. All patients had sterile pyuria and each of nine patients studied by Wright's stain of urine sediment had marked eosinophiluria. These findings are suggestive of methicillin-induced interstitial nephritis, although proteinura was a variable finding in our patients. Eight of 14 patients in our study received prednisone therapy for their interstitial nephritis, and the time lapse between maximal and final base line serum creatinine levels was statistically less in the prednisone-treated compared to the nontreated groups. Clinical manifestations of this syndrome are discussed, and the light and electron microscopic and immunofluorescent findings on renal biospy are described.

Adult↗
PubMed1978

Determination of lipid A and endotoxin in serum by mass spectroscopy.

A quantitative technique for determining lipid A content of endotoxin added to serum by combined gas chromatography-mass spectrometry is described. This technique uses detection of the beta-hydroxymyristic acid content of Salmonella minnesota R595 lipopolysaccharide by selected ion monitoring at atomic mass unit of 315.4 The fatty acids produced on hydrolysis of serum containing lipopolysaccharide were extracted and the methyl esters were made. Silica gel chromatography was used to separate methyl esters of hydroxy fatty acids from other fatty acid methyl esters. Trimethylsilyl ether derivatives of the hydroxy fatty acid methyl ester fraction were quantitated by this technique. As little as 200 fmol of beta-hydroxymyristic acid could be detected.

Journal Article↗
PubMed1978

Treatment of cutaneous Herpesvirus hominis type 2 infection with 8-methoxypsoralen and long-wave ultraviolet light in guinea pigs.

Treatment of cutaneous Herpesvirus hominis type 2 infection in albino guinea pigs with 8-methoxypsoralen plus long-wave ultraviolet light was evaluated by clinical assessment and quantitative viral cultures. There was a statistically significant difference between the treated animals and the controls in relation to vesicular development, rate of healing, and viral titers. The treatment was effective after the appearance of lesions, when viral multiplication has already begun.

Animals↗
PubMed1978

Outbreak of multiply drug-resistant Proteus mirabilis originating in a surgical intensive care unit: in vitro susceptibility pattern.

A multiply drug-resistant strain of Proteus mirabilis was isolated from 14 patients on a surgical service. Antimicrobial susceptibility studies demonstrated that the organism was highly resistant to numerous antibiotics, including gentamicin, tobramycin, and sisomicin. The organism was susceptible in vitro to amikacin but had low-level resistance to netilmicin. In vitro susceptibility studies with combinations of cephalothin with netilmicin and trimethoprim with sulfamethoxazole showed these drugs to be synergistic. Other drug combinations failed to act synergistically.

Cross Infection↗
PubMed1978

Quantitation of antibiotics by high-pressure liquid chromatography: cephalothin.

A technique for quantitative determination of cephalothin and desacetylcephalothin in serum using a method based on high-pressure liquid chromatography is described. Both compounds were quantitatively extracted from serum by using dimethylformamide. After separation of the drugs by reverse-phase chromatography and detection by ultraviolet light absorption at 254 nm, serum concentrations of cephalothin and desacetylcephalothin as low as 1.0 mug/ml were measured. No interfering absorption was found in extracts of serum samples from normal humans or patients receiving a variety of other drugs, including other antimicrobial agents. Serum specimens obtained after an intravenous infusion of cephalothin to two human subjects and three dogs were assayed by the chemical and microbiological assays. When values, as determined by the chemical method and the microbiological assay in samples from human subjects, were compared, the correlation coefficient (r) was 0.96, whereas, in the dogs, the r value was 0.79. The chemical procedure described in this report for determination of cephalothin and desacetylcephalothin permits future pharmacokinetic investigations of these compounds. This assay is sensitive, specific, accurate, and rapid (approximately 30 min), and appears suitable for routine clinical use.

Animals↗
PubMed1978

Susceptibility of 40 lactobacilli to six antimicrobial agents with broad gram-positive anaerobic spectra.

The minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of 40 lactobacillus strains were determined against six antibiotics with broad anaerobic spectra. Penicillin, ampicillin, clindamycin, and cephalothin were the most active inhibitory agents, with 95 to 100% of the strains inhibited at clinically achievable serum levels. However, despite the inhibitory efficacy of these four agents, only 5 to 22% of the isolates were killed at achievable concentrations. MBC:MIC ratios were high, ranging from 30:1 for cephalothin to 266:1 for ampicillin. Cefoxitin and metronidazole were generally ineffective against lactobacilli, with 87.5 to 100% of strains having unachievable MICs and/or MBCs. These findings may partially explain the clinical observations noting the inability to eradicate endocarditic lactobacillemias despite readily achievable MICs.

Anaerobiosis↗
PubMed1978

Amikacin assay in serum by high-performance liquid chromatography.

A high-performance liquid chromatographic method for the quantitative determination of amikacin in serum is described. The antibiotic was separated from serum by adsorption on silica gel. The adsorbed drug was then derivatized with o-phthalaldehyde and eluted with ethanol. The derivatized amikacin was separated by reverse-phase, high-performance liquid chromatography and quantitated by fluorometry. A linear response for serum samples containing amikacin ranging from 1.0 to 15 mug/ml was obtained. Other antibiotics including various aminoglycosides did not interfere with the amikacin assay. Comparison with a standard microbiological assay gave a correlation coefficient of 0.99. This chemical assay is sensitive and specific under the conditions tested and can be performed rapidly.

Amikacin↗