Biomedical subjects
Publications and source records attributed to R B Brown.
This report reviews the successful surgical experience with a diabetic patient with bronchial obstruction due to Mucorales infection. A review of the reported medical and surgical experience is included. The danger of a lethal pulmonary hemorrhage makes early surgical intervention mandatory.
While the bacterial origin of otitis media has been studied extensively in children, there are few data regarding adults with this disease. We undertook this study to identify the incidence, prevalence, and bacteriologic origin of purulent otitis media in adults. This was accomplished through a review of the English-language literature on adult otitis media and a retrospective review of adult patients with this disease who were hospitalized at our institution. Results of literature review indicate that Streptococcus pneumoniae and Haemophilus influenzae are the most common causes of otitis media in ambulatory adults, but this illness is uncommon, with an incidence of only 0.25%. Hospitalized patients in whom this diagnosis was established suffered a variety of serious suppurative complications such as mastoiditis, meningitis, or brain abscess. Otalgia and fever were the most common symptoms noted in this patient population. Further studies of adult otitis media need to be performed to determine bacteriologic, symptomatic, and high-risk patient groups.
Ammonium and potassium ion-selective membranes formulated with PVC/hydroxylated PVC, polyurethane/hydroxylated PVC, and moisture-curable silicone rubber matrices are studied in an effort to extend the lifetime of solid-state ion sensors through improved membrane adhesion. The PVC/membranes exhibit electrochemical performance equivalent to that of conventional PVC membranes in terms of slope, detection limit, and selectivity. The polyurethane- and silicone-rubber-based membranes have better adhesion to silicon nitride than do PVC or hydroxylated PVC matrices. Incorporating a silanizing reagent (silicon tetrachloride) significantly improves the adhesion of the polyurethane matrix. The use of silicon tetrachloride in membrane matrices also enhances the electrochemical stability of the interfacial potential between ion-selective polymer-matrix membranes and silver epoxy inner reference electrodes of solid-state sensors. The biocompatibility of the polymer matrices is examined via radiotracer protein adsorption studies and whole blood clotting time measurements. The polyurethane- and silicone-rubber-based membranes exhibit less overall nonspecific protein adsorption than the PVC or hydroxylated PVC matrices.
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Neuropeptides may be used to stimulate or inhibit neurocircuitry involved in regulation of visceral organ function, including glucose metabolism. Through the use of different peptides with different specificities, it may be possible to characterize the neuroendocrine and autonomic pathways involved in the physiologic regulation of glucose homeostasis.
This study compared the effect of "standard" dose metaproterenol delivered by hand-held nebulizer (HHN) with two puffs of metaproterenol delivered by a metered dose inhaler (MDI) via a spacer (InspirEase) (MDI-spacer). Seventeen patients with an acute exacerbation of obstructive pulmonary disease were studied. Each patient received both MDI-spacer and HHN. Alternate patients were randomized to either MDI-spacer or HHN as initial treatment. Each subject was tested four different times: before and 30 minutes after the initial aerosol delivery technique, and before and 30 minutes after the alternate aerosol delivery technique. Testing consisted of spirometry, lung auscultation, and measurement of vital signs. The interval between treatments for all subjects was 2.96 +/- 0.27 hours (mean +/- SEM) and was not different for subjects who received therapy via MDI-spacer first or HHN first. The patient population studied demonstrated severe airways obstruction (baseline FEV1 33.3 percent predicted +/- 4.9 percent). There was a statistically significant improvement in FVC and FEV1 after metaproterenol delivered by HHN, but not after MDI-spacer. Metaproterenol treatment with HHN resulted in a greater improvement in FEV1 (p less than .05) than MDI-spacer when the data were reported as absolute improvement (0.19 +/- 0.05 L for HHN) vs (0.06 +/- 0.03 L for MDI-spacer) or reported as percent change (23.2 +/- 6.6 percent for HHN) vs (9.5 +/- 3.4 percent for MDI-spacer). Asthmatic patients exhibited a significantly greater (p less than 0.05) improvement in FEV1 after HHN (23.4 +/- 4.7 percent change) than after MDI-spacer (6.6 +/- 4.5 percent change). Patients with chronic obstructive pulmonary disease (COPD) exhibited a greater improvement in FVC (p less than 0.05) after HHN (25.2 +/- 6.7 percent change) than after MDI-spacer (5.8 +/- 4.7 percent change). We conclude that the "standard" dosage of metaproterenol delivered by HHN results in greater spirometric improvement in patients with acute obstructive pulmonary disease than the conventional dosage of metaproterenol delivered by MDI-spacer. It is likely that this reflects the fact that the recommended dose of metaproterenol delivered by MDI is too low and should be increased.
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Comparison of 35 elderly patients hospitalized with pneumonia acquired in nursing homes and 35 elderly patients hospitalized with community-acquired pneumonia showed that 16 (47.1%) of the nursing home patients had received previous antibiotic therapy compared with two (5.9%) of the community patients. Klebsiella pneumoniae was isolated in 14 (40%) of the nursing home patients, but in only three (8.6%) of the community patients. Staphylococcus aureus was also more frequent in nursing home patients (nine, 25.7%) compared with community patients (five, 14.3%). Persons hospitalized with nursing home-acquired pneumonia should be treated initially with antimicrobial agents active against K pneumoniae and S aureus unless the clinical picture strongly suggests otherwise.
The student administration and admissions functions of the College respond to numerous and diverse students needs and interests. The complexity of these programs, and the concept of this report precludes offering exacting detail or even mention of all activities encompassed under the concept of academic support services. The increased public interest in veterinary medicine has prompted significant increases in the number who apply each year. This causes particular emphasis to be given to the College Admissions program. Rapidly escalating costs of education mean increased dependency of students on our financial aid program at a time of static and potentially decreasing financial aid resources. Placement of graduates in the best possible employment opportunities has been and will continue to be vital to our overall missions. Involvement by students in activities beyond those purely curricular in nature, will always be critical to the health and growth of the College and the public it serves.
This paper details the aetiology, presentation, diagnosis, prophylaxis, treatment, and results, of 84 surgical and external ureteric injuries. Although the incidence of surgical ureteric trauma was found to be low it was related to both the particular operation performed and certain faults in surgical technique. The series emphasizes the importance of prophylaxis, early diagnosis, and specific therapy. There were 94 operations carried out on the 84 ureters, resulting in 22 nephrectomies and 63 open repair procedures, of which 55 were regarded as successful and 8 as failures.
Clindamycin phosphate, 600 mg, was given intravenously to 14 patients undergoing biliary tract surgery. Seven had complete obstruction of the common bile duct. Concentrations of total and active (nonesterified) antibiotic were measured in serum, gall bladder and common duct bile, gall bladder wall, and liver. Persons with patent common ducts had high levels of active drug at all hepatobiliary sites; concentrations were two and one half to three times higher in bile and liver than in serum. Persons with obstruction of the common duct had no measurable drug in bile and had reduced levels in gall bladder wall; however, concentrations in the liver were slightly higher than those in the group without obstruction. The results of this study suggest that, even in the presence of common duct obstruction, the concentrations of active clindamycin in the liver may be sufficient to limit the spread of intrahepatic infections due to susceptible organisms.
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Linomycin and clindamycin phosphate were studed in a canine model in which acute biliary obstruction was produced during iv infusion of antibiotic. Hepatic and renal extraction, bilary and renal excretion, and concentrations in liver and kidney were measured. Total and nonesterified clindamycin were assayed. The antibiotics were taken up by the liver at similar rates; however; the rates of excretion and concentration in bile were significantly higher for lincomycin than for clindamycin. Biliary obstruction did not affect the concentration of either antibiotic in canalicular bile. Lincomycin was extracted by the kidneys and excreted into urine at a much higher rate than was clindamycin. Concentrations of nonesterified clindamycin in the hepatic vein were higher than those in the portal vein, an observation suggesting metabolic activation within the liver. This relation was reversed by bilary obstructon. The results in this canine model indicate a greater role for the kedney in the disposition of lincomycin than in that of clindamycin, major differences between the rates of biliary excretion of the two agents, and a probable change in the metabolism of clindamycin procued by acute bilary obstruction.
Data from 42 patients were analyzed to determine the predictability of the peak serum level and the t1/2 of gentamicin on the bases of age, sex, body weight, serum concentration of creatinine, and blood hematocrit. Renal function was normal in 21 patients and impaired in 21. The most striking finding was the relatively poor predictability of t1/2 of gentamicin from serum concentration of creatinine. The overall correlation coefficient was 0.749 (P less than 0.001) in contrast to values of greater than 0.9 reported by others. tthere was a significant correlation of the t1/2 of gentamicin with the reciprocal of hematocrit (r * 0.647, P less than 0.001). Linear regression equations taking account of sex, serum creatinine concentration, and reciprocal of hematocrit provided a somewhat higher correlation coefficient (0.821) with the t1/2 of gentamicin than did the equation including serum creatinine concentration alone but were still not fully satisfactory. Thus the pharmacokinetics of gentamicin may not be adequately predictable from standardized equations or nomograms.
Four tetracyclines were studied in dogs to determine the relation between their lipophilicity and various other pharmacological characteristics. Lipid solubility correlated inversely with the mean concentration of drug in arterial plasma and renal uptake and excretion, and directly with the biliary concentration gradient (level in bile/level of free drug in serum). Only the more lipophilic congeners minocycline and doxycycline passed the blood-brain and blood-ocular barriers in detectable concentrations. Mean levels of minocycline in the brain exceeded those of doxycycline by almost threefold; the difference was of borderline statistical significance (P = 0.05 to 0.1). Lipophilicity correlated inversely with the concentration of antibiotic in renal medulla but not in renal cortex or in the liver. When intestinal loops containing saline, milk, or 10% Gelusil were studied, the only combination exhibiting striking intraluminal accumulation was doxycycline in milk. These results indicate that lipophilicity correlates with many, but not all, of the transport characteristics of tetracycline antibiotics.