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Biomedical subjects

L Louie

Publications and source records attributed to L Louie.

31 records · Page 2Linked to original sources
PubMed1998

Amphotericin B in lipid emulsion: stability, compatibility, and in vitro antifungal activity.

Newer formulations of amphotericin B (AmB) complexed with liposomes or lipid suspensions have been developed. Preliminary studies have suggested that AmB in Intralipid (IL) may be as effective as, but less toxic than, conventional formulations of AmB, but few data are available regarding its stability, compatibility, or in vitro antifungal activity. A compatibility study was done to evaluate the effects of AmB concentrations in IL containing either 10 or 20% soybean oil. The effects of temperature, shaking, and AmB and IL concentrations on the stability of AmB-IL suspensions were analyzed by visual inspection and liquid chromatography. The in vitro antifungal activity of AmB-IL, compared to that of AmB alone against reference strains of Candida species was determined by using a broth macrodilution method in accordance with National Committee for Clinical Laboratory Standards guidelines (M27-T). Samples of AmB-IL which were lightly shaken retained more than 90% of the AmB concentration over 21 days when stored at either 4 or 23 degrees C. Varying the AmB concentration did not appear to affect the stability of AmB-IL. However, a precipitate was formed when mixtures with more than 30% lipid as a proportion of the total volume were centrifuged. AmB-IL and AmB alone had similar in vitro antifungal activities against reference strains of yeasts. Further pharmacologic and clinical studies with AmB-IL are warranted, although AmB should not be combined with IL in concentrations capable of producing a precipitate.

Amphotericin B↗
PubMed1998

Application of multiplex PCR for detection of non-O157 verocytotoxin-producing Escherichia coli in bloody stools: identification of serogroups O26 and O111.

Primers were designed to amplify sequences of verocytotoxin genes and eaeA genes of Escherichia coli O26:H11, O111:H8, and O157:H7 in a multiplex PCR assay. This assay successfully detected E. coli O26:H11 in bloody stool specimens in which other enteric pathogens were not detected by culture-based methods. Rapid assays to detect non-O157:H7 verocytotoxin-producing E. coli is important to improve methods for the etiologic diagnosis of hemorrhagic colitis.

Adhesins, Bacterial↗
PubMed1998

Diagnosis of group A streptococcal necrotizing fasciitis by using PCR to amplify the streptococcal pyrogenic exotoxin B gene.

This study evaluated a PCR assay for detection of the streptococcal pyrogenic exotoxin B (speB) gene from tissue biopsy specimens of patients with necrotizing fasciitis. speB was detected in specimens from all 10 patients with necrotizing fasciitis due to group A streptococcus. The assay was negative for all 11 patients without culture or serologic evidence of streptococcal infection. These results suggest that the detection of speB by PCR may be useful for confirming group A streptococcal infection when cultures are negative or not available.

Bacterial Proteins↗
PubMed1998

A tobacco and alcohol use profile of San Francisco's Chinese community.

Relatively little is known about Asian American tobacco and alcohol use patterns. This is particularly true of Chinese living in the United States--either U.S.-born or non-U.S.-born Chinese. This article presents data from a research project studying tobacco and alcohol use patterns in San Francisco's Chinese community. Data were secured both from focus groups and a self-report telephone survey of a random sample of 1,808 Chinese residents in San Francisco. This results indicate that the prevalence of both tobacco and alcohol use is lower for San Francisco's Chinese population than for the general population. Moreover, those persons who report smoking tend to be different from those who report consuming alcohol. The study concludes that specific, culturally relevant tobacco and alcohol prevention programs should be designed to better reach this target population.

Adolescent↗
PubMed1997

Antifungal susceptibility testing of yeast isolates from blood cultures by microbroth dilution and the E test.

The results of microbroth dilution were compared with those of the E test for 169 yeast isolates tested for their susceptibility to antifungal agents. All isolates were tested by both methods against amphotericin B, ketoconazole, fluconazole, and itraconazole. The E test results generally correlated well with those obtained by the reference method. There was at least 80% agreement of minimum inhibitory concentration results within two dilutions for all yeast species and agents tested, except for Cryptococcus neoformans tested with fluconazole (8% agreement). The E test appears to be a suitable alternative antifungal susceptibility test method for yeasts, although improvements are required for testing Cryptococcus neoformans against fluconazole.

Antifungal Agents↗
PubMed1997

Nosocomial Neisseria meningitidis: molecular analysis of a clinical problem.

Over a 1-week period, Neisseria meningitidis serogroup B was recovered from two patients in the intensive-care unit (ICU). A cross-infection was presumed when one patient developed invasive meningococcal disease and another patient was found to be colonized. Investigation by molecular typing showed that these cases were not related, demonstrating the value of molecular typing when investigating potential cross-infections in a closed environment such as the ICU.

Cross Infection↗
PubMed1997

Investigation of a pseudo-outbreak of Nocardia asteroides infection by pulsed-field gel electrophoresis and randomly amplified polymorphic DNA PCR.

Molecular strain typing by pulsed-field gel electrophoresis and by randomly amplified polymorphic DNA analysis was used to investigate a cluster of four Nocardia asteroides isolates associated with the BACTEC 460 TB system. An instrument motor drive misalignment resulted in inadequate needle sterilization and cross-contamination of BACTEC vials. This pseudo-outbreak illustrates the importance of proper BACTEC 460 needle sterilization and maintenance and confirms the usefulness of molecular typing methods for epidemiologic investigations.

Bacterial Typing Techniques↗
PubMed1995

Comparison of E test and agar dilution for antimicrobial susceptibility testing of Stenotrophomonas (Xanthomonas) maltophilia.

Currently recommended dilution test methods for the determination of antimicrobial susceptibility of Stenotrophomonas (Xanthomonas) maltophilia are labor-intensive and often impractical in many clinical laboratories. We compared the E test with the agar dilution method for susceptibility testing of 176 clinical isolates of S. maltophilia against 16 antimicrobial agents. The MICs obtained by E test correlated well with those determined by the agar dilution method, with an overall agreement of 94%. Very major and major errors occurred infrequently (0.6 to 2.9%) when testing beta-lactam agents, tobramycin, trimethoprim-sulfamethoxazole, and fluoroquinolones. The E test was found to be accurate and easy to perform. For most antimicrobial agents tested against S. maltophilia, the E test is an acceptable alternative susceptibility test method.

Agar↗
PubMed1992

Genetic risk factors for perinatally acquired HIV-1 infection.

This study evaluates genetic influence on susceptibility to perinatal HIV-1 infection among 106 Black infants from New York and San Francisco born to mothers infected with HIV-1. Genes tested by molecular techniques are HLA class II loci DRB1, DPB1 and DQA1; HLA class III loci complement C4A and C4B; alpha and beta interferons; and the constant region of the T-cell receptor beta chain. Of the 106 infants analysed, 54 are infected with HIV and 52 remain uninfected at age 15 months and older. Genotypes in the HLA region appear to influence risk of HIV infection. Specifically, infants with the amino acid sequence -asp-glu-ala-val- at DPB1 positions #84-87 are more likely to be infected (P = 0.001) and infants with the allele DQA1*0102 are less likely to be infected (P = 0.031). Combinations of these two risk factors show a strong dose response (P = 0.0005). HLA DPB1 and DQA1 may play a direct role in immune response associated with HIV-1 infection, or the critical region may be located between these two genes. Characterisation of other class II HLA genes in these infants will allow more precise determination of the role of HLA loci in susceptibility to HIV-1 infection.

Alleles↗
PubMedDate not supplied

Laboratory tests during resuscitation.

The drawing of laboratory tests is often overlooked in the moribund patient. In patients with medical problems, potassium and other electrolyte abnormalities are often of significance and may be the cause of the arrest. Patients without circulation begin to develop severe abnormalities of PT, PTT, and potassium. These measurements will sometimes demonstrate that a patient's condition is hopeless. When laboratory tests show a situation to be hopeless, an early cessation of resuscitation efforts will be possible, and the justification for such actions will be documented. Laboratory tests drawn early in the resuscitation effort may prove that resuscitation could not have been successful.

Blood Chemical Analysis↗
PubMedDate not supplied

Influence of host genetics on the severity of coccidioidomycosis.

Coccidioidomycosis, a mild flulike illness in approximately 40% of infected persons, progresses to severe pulmonary or disseminated disease in 1% to 10% of symptomatic cases. We examined host genetic influences on disease severity among class II HLA loci and the ABO blood group. Participants included African-American, Caucasian, and Hispanic persons with mild or severe disseminated coccidioidomycosis from Kern County, California. Among Hispanics, predisposition to symptomatic disease and severe disseminated disease is associated with blood types A and B, respectively. The HLA class II DRB1*1301 allele marks a pre-disposition to severe disseminated disease in each of the three groups. Reduced risk for severe disease is associated with DRB1*0301-DQB1*0201 among Caucasians and Hispanics and with DRB1*1501-DQB1*0602 among African-Americans. These data support the hypothesis that host genes, in particular HLA class II and the ABO blood group, influence susceptibility to severe coccidioidomycosis.

ABO Blood-Group System↗