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Biomedical subjects

L K Pickering

Publications and source records attributed to L K Pickering.

At least 199 records · Page 11Linked to original sources

Mechanisms of host defense in well nourished patients with chronic alcoholism.

Tests of immune function were performed on five recently abstinent, well nourished,and disease-free patients with chronic alcoholism. No significant defects in adherence, metabolic, or bactericidal activity of polymorphonuclear leukocytes were found when compared to sex-matched controls. Antibody-dependent and natural killer cellular cytotoxicity of monocyte-macrophages and lymphocytes also were normal. These data support the concept that immunity might be intact in the group of patients with chronic alcoholism who are recently sober, well nourished, and free of underlying disease.

Alcoholism↗

The role of location of food consumption in the prevention of travelers' diarrhea in Mexico.

The location of food consumption was recorded daily for 3 wk by 130 United States summer students newly arrived in Guadalajara, Jalisco, Mexico, as part of an assessment of bismuth subsalicylate vs. placebo in the irevention of travelers' diarrhea. Eating at locations other than homes and apartments (P < 0.025), and specifically at restaurants, was associated with an increased occurrence of diarrhea. Less eating at restaurants (P < 0.005), street vendors (P < 0.005), and school cafeterias (P < 0.01) was associated with reduced occurrence of travelers' diarrhea, even among persons taking bismuth subsalicylate as a preventive measure.

Bismuth↗

Orbital cellulitis due to Neisseria gonorrhoeae in an enucleated socket.

Orbital cellulitis due to Neisseria gonorrhoeae developed in an adolescent girl in a previously enucleated socket. Since this organism also was isolated from her pharynx, the orbital infection probably resulted from contamination of the prosthesis by gonococci from her mouth, either directly or by transfer from her fingers.

Adolescent↗

Current concepts of bacteremia in children with malignancies.

One hundred fifteen episodes of bacteremia occurred among 2790 children with malignancies hospitalized during a 45-month period. The mean age was 9.3 years with a male predilection (62%). A greater (p less than .025) number of children over 10 years of age died with bacteremia when compared to younger children. The majority of episodes occurred in children with leukemia (56%); however, once bacteremia developed, a significantly (p less than .05) greater number of children with lymphoma died when compared to children with other malignancies. Absolute polymorphonuclear leukocyte counts were greater in survivors (p less than .025) than in children who died. Thirty-seven different microorganisms were isolated with E. coli, S. Aureus, P. aeruginosa, and K. pneumoniae accounting for 50% of the episodes. Anaerobes were isolated from blood of 12 (10%) children. Twelve children had polymicrobial bacteremia and 14 had recurrent bacteremia which occurred during antibiotic therapy. Mortality (78%) in these children was significantly (p less than .001) greater then in children from whom one microorganism was isolated (47%). Interesting aspects include the resurgence of S. aureus, failure of development of meningitis in children with bacteremia, and unchanged antibiotic susceptibility since the last review of bacteremia in this institution. Polymicrobial and recurrent bacteremia necessitate obtaining simultaneous and sequential blood cultures to facilitate administration of appropriate antimicrobial therapy until bone marrow function improves.

Adolescent↗

Multiple-dose amikacin kinetics in pediatric oncology patients.

Amikacin kinetics was studied in 8 pediatric oncology patients who received the drug by intravenous infusion over 30 or 60 min at a dose of 5 mg/kg every 6 or 8 hr. This regimen is recommended but, due to patient variability, patients should be monitored. Dosing intervals during 1 or 2 and 3 or 4 days of therapy were studied with serum samples collected before and at the end of the infusion and serially to the end of the dosing interval. The data appeared consistent with and were analyzed according to 1-compartment model. An equation describing serum concentration with time for the multiple-dose case was fit to each patient's multiple-interval data with nonlinear regression. Half-life averaged 1.2 hr. volume of distribution 0.24 l/kg, and total body clearance 109 ml/min/1.73 m2 or 2.51 ml/min/kg. The volume of distribution and the clearance are greater than reported for adults and probably account for the larger dose needed to achieve and maintain therapeutic levels. Although the total daily dose was greater than previously reported, there were no signs of toxicity, although therapuetic concentrations were maintained.

Adolescent↗

Human rotavirus in an adult population with travelers' diarrhea and its relationship to the location of food consumption.

The role of human rotavirus in adult diarrhea was evaluated in 164 newly arrived US students attending summer school at an urban Mexican university. Rotavirus was identified in stool samples by electron microscopy. Rotavirus was found in 26 of 109 students with diarrhea (24%) and in 8 of 55 asymptomatic control students (15%). Although bacterial pathogens were recovered from virus positive students with diarrhea, viral shedding also occurred independently of other agents. Clinical disease in students excreting only rotavirus tended to be mild and was accompanied by a low density of viral shedding. Food consumption in the home and at public eating establishments was examined the week before illness. While the location of food consumption was found to be important in the acquisition of diarrhea, there was no apparent relationship of the site where meals were eaten and the acquisition of rotavirus by students newly arrived in Mexico. These data support our previous study in a US student population residing in a rural setting in Mexico and implicate rotavirus as a cause of diarrhea among students traveling to Mexico from the United States. The present study offers additional evidence that rotavirus infection in this population might be spread by a nonfood vehicle of transmission which differs from spread of enterotoxigenic E coli, Shigella, or Salmonella strains in the same population.

Adolescent↗

Systemic absorption of bacitracin after peritoneal lavage.

Nine patients underwent intraoperative peritoneal lavage with a solution containing 50,000 units of bacitracin in 200 ml of 0.9 per cent sodium chloride. The solution was removed by suction at 2 or 5 minutes, and venous blood samples were obtained at 15 minute intervals for 2 hours after lavage. Concentrations of bacitracin in serum were determined by agar diffusion assay. In the majority of patients, peak concentrations of bacitracin in serum occurred by 15 minutes post lavage. The mean peak serum concentration was 3.8 units/ml, which exceeds peak concentrations after intramuscular injection of 50,000 units. Due to potential nephrotoxicity, bacitracin should be used cautiously in peritoneal lavage solutions and should be abandoned in patients who have renal impairment in whom prolonged elevated serum concentrations could develop.

Absorption↗

Inhibition of human monocyte-macrophage and lymphocyte cytotoxicity to herpes simplex-infected cells by glucan.

The effect of short term in vitro incubation of glucan--a reticuloendothelial system stimulator--on subsequent cytotoxicity of human monocyte-macrophages (MP) and lymphocytes (L) to Herpes simplex virus-infected cells in a 51Cr-release assay was analyzed. Particulate, cell-associated glucan irreversibly inhibited MP antibody-dependent cellular cytotoxicity (ADCC). In contrast, the inhibition of L-ADCC and L-natural killer cytotoxicity could be reversed by dissociation of glucan and cells utilizing serum gradient centrifugation, a process which did not remove the glucan. These experiments reveal further basic differences between MP and L-ADCC using the reagent glucan.

Cytotoxicity, Immunologic↗

Effect of time and concentration upon interaction between gentamicin, tobramycin, Netilmicin, or amikacin and carbenicillin or ticarcillin.

An aminoglycoside antibiotic and carbenicillin or ticarcillin are widely used in the treatment of patients with gram-negative bacillus infections. This study evaluated the effect of time upon in vitro interaction between mixtures of four aminoglycosides at two concentrations with carbenicillin or ticarcillin at four concentrations. By linear regression analysis, the inactivation of each aminoglycoside was shown to be directly proportional to the concentration of carbenicillin (P < 0.001). Inactivation was significantly (P < 0.01) greater for gentamicin and tobramycin than for amikacin or netilmicin at all carbenicillin concentrations. At carbenicillin concentrations of 300 and 600 mug/ml, significantly (P < 0.005) less inactivation of amikacin occurred when compared to netilmicin. Ticarcillin produced a significant (P < 0.025) inactivation of gentamicin and tobramycin, with inactivation being directly proportional to ticarcillin concentration. No inactivation of amikacin or netilmicin activity occurred unless the ticarcillin concentration was 600 mug/ml. No significant change in aminoglycoside activity occurred when stored with ticarcillin or carbenicillin at concentrations ranging from 100 to 600 mug/ml at -70 degrees C for 56 days. When an aminoglycoside and carbenicillin or ticarcillin are indicated in patients with renal failure, this study supports the use of ticarcillin with either amikacin or netilmicin.

Amikacin↗

Amikacin pharmacokinetics in pediatric patients with malignancy.

The pharmacokinetics of amikacin were evaluated in 50 pediatric patients (1 to 17 years of age) with malignancies and normal renal function. Dosage regimens of 5 mg/kg per dose were administered intravenously (i) over 30 min every 8 h, (ii) over 60 min every 8 h, and (iii) over 60 min every 6 h. Administration of amikacin over 30 min produced concentrations in serum of 29.3 +/- 5.7 micrograms/ml at the end of the infusion and subtherapeutic concentrations 4 h after the infusion. The regimen of 20 mg/kg per 24 h, divided into doses given every 6 h infused over 60 min, achieved concentrations in serum at the end of the infusion of 17.2 +/- 1.7 micrograms/ml and at 6 h of 1.2 +/- 0.3 microgram/ml. The serum half-life was 1.24 +/- 0.09 h, volume of distribution was 0.26 +/- 0.02 liter/kg, and total body clearance rate was 131 +/- 10 ml/min per 1.73 m2. No accumulation of amikacin was noted, and no significant side effects could be attributed to the drug. This study suggests that the optimal initial dosage regimen of amikacin in children is 20 mg/kg per 24 h administered in equal doses every 6 h over 60 min; however, optimal therapy requires individualization of dosage based on measured serum concentrations and susceptibility data on bacterial pathogens isolated.

Adolescent↗

[Acute infectious gastroenteritis. Etiology and its correlation with clinical manifestations and fecal mucus].

343 children with acute diarrhea were studied from january 1976 to september 1977. Rotavirus was the agent most frequently isolated (18 per cent) followed by Shigella (12 per cent) and Salmonella (10 per cent). Enterotoxigenic E. coli was identified in 8 per cent and invasive E. coli only in two cases. 80 per cent of isolated rotavirus fell in the neonate group and 25 per cent in the infant group. Diarrhea caused by rotavirus had a short duration, fever was negligible and abundant liquid stools were present without leukocytes in the fecal mucus and with a high percentage (48 per cent) of transient lactose intolerance. Polymorphonuclear leukocytes were found in fecal mucus in 75 per cent of cases caused by Shigella and only in 40 per cent of cases where the causal agent was Salmonella.

Adenoviridae↗

Gastroenteritis due to enteropathogenic, enterotoxigenic, and invasive Escherichia coli: A review.

Escherichia coli that produce diarrhea can be divided into three groups: 1) enteropathogenic, 2) enterotoxigenic, and 3) enteroinvasive. The mechanism of disease production by enteropathogenic E. coli is unknown, but these strains are not presently known to be inherently pathogenic, although they may be important as a cause of gastroenteritis in infants. The two known mechanisms of disease production are elaboration of enterotoxin and mucosal invasion. Heat-labile toxin-producing E. coli are the main cause of diarrhea in travelers while heat-stable toxin-producing E. coli are a cause of scours among new-born swine and cattle. Enteroinvasive E. coli have not been shown to be an important cause of diarrhea in the United States. Enteropathogenic, enterotoxigenic, and enteroinvasive E. coli that currently are associated with diarrhea worldwide may each consist of relatively few serotypes different from those associated with out-breaks of diarrhea in the past. This implies a possible new role for sero-typing of E. coli.

Adult↗

Single-dose tetracycline therapy for shigellosis in adults.

Forty-two adults who had Shigella isolated from stool (26 symptomatic, 16 asymptomatic) received a single oral dose of tetracycline hydrochloride (2.5 g). Minimal inhibitory concentrations of the 42 isolates demonstrated that 41% were sensitive to tetracycline. Sixteen of 18 patients with diarrhea who had tetracycline-resistant Shigella and all eight patients with diarrhea who had tetracycline-sensitive Shigella were clinical well and had Shigella-negative stools 48 hours after therapy. Fifteen of 16 asymptomatic patients demonstrated clearing of Shigella from stool within 48 hours of therapy. Single-dose tetracycline therapy is effective in the treatment of Shigella regardless of clinical expression of illness or in vitro sensitive of the organism.

Adult↗

Intraventricular and parenteral gentamicin therapy for ventriculitis in children.

Five children with intraventricular shunts developed ventriculitis due to organisms resistant to multiple antimicrobial agents but sensitive to gentamicin sulfate. No gentamicin was detected in ventricular CSF of four patients at a time when gentamicin was being administered only intravenously. The intraventricular administration of 1 mg of gentamicin resulted in ventricular CSF concentrations greater than 20 microgram/ml one hour and 5 to 14 microgram/ml 36 hours after administration. Patients were treated with intraventricularly given gentamicin for an average of 16 days, with no apparent complications or relapses during the 12- to 24-month follow-up period. Intraventricularly administered gentamicin sulfate (1 mg every 24 to 36 hours) in conjunction with complete shunt removal was an effective means of therapy of ventriculitis caused by bacteria resistant to antibiotics that readily penetrate the blood-brain barrier.

Cerebral Ventricles↗

Effect of chemotherapeutic agents on metabolic and bactericidal activity of polymorphonuclear leukocytes.

Blood was obtained on 36 occasions from 12 healthy adult volunteers and the polymorphonuclear leukocytes (PMNL) were separated. PMNL hexose monophosphate shunt activity of whole blood and ability of separated cells to phagocytize and kill E. coli were evaluated when the PMNL were incubated with normal pooled sera and sera containing therapeutic concentrations of either 15 cancer chemotherapeutic drugs singly and in combination or 9 antibiotics. Resting and stimulated HMPS activity was significantly (p less than 0.025 to p less than 0.001) decreased by cyclophosphamide, carmustine (BCNU), high dose prednisone (pred), vinblastine (vinbl) and vincristine (vinc) and significantly (p less than 0.025 to p less than 0.01) increased by combinations of vinc-pred, vinc-predasparaginase, 6-mercaptopurine (6MP)-methotrexate (Mtx) and 6MP-Mtx-pred when compared to controls. No significant differences in HMPS activity of PMNL were found when exposed to various antimicrobial agents singly or in combination. The killing of E. coli by PMNL was significantly (p less than 0.001) decreased when exposed to BCNU, high concentration pred or combinations of 6MP-Mtx-pred, 6MP-Mtx and vinc-vinbl-pred but not when exposed to other chemotherapeutic agents. This study shows a disparity in results obtained when evaluating PMNL function by HMPS activity and bactericidal assay. In addition, a functional impairment in PMNL exposed to various antimetabolites occurred at a time when they exhibited normal morphology.

Anti-Bacterial Agents↗