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R L Buck

Publications and source records attributed to R L Buck.

17 recordsLinked to original sources
PubMed1993

Performance of a fluorescence polarization immunoassay for teicoplanin in serum.

Teicoplanin is a new glycopeptide antibiotic that is structurally related to vancomycin, but has six major components and is > 90% protein bound. We have developed a competitive homogeneous fluorescence polarization immunoassay (FPIA) for the quantitative determination of teicoplanin in serum. The teicoplanin FPIA uses six serum-based calibrators over the range 0-100 micrograms/ml, with the lowest teicoplanin concentration at 5 micrograms/ml and a lower limit of detection of < 1.5 micrograms/ml. Samples with concentrations > 100 micrograms/ml can be analyzed after 1:5 dilution with serum. Intra- and interassay precision are < 2% and < 4.5%, respectively, for controls at 7.5, 35, and 75 micrograms/ml on an automated FPIA analyzer. Recovery results for 30 samples prepared from the teicoplanin analytical reference standard over the range 3.4-358 micrograms/ml were linearly correlated with target concentrations; the linear regression equation and correlation coefficient are FPIA = 0.976 x target + 0.120, r = 0.999. Abnormal levels of bilirubin, hemoglobin, albumin, triglycerides, or cholesterol did not significantly affect recovery. Cross-reactivity with vancomycin was < 0.2%, and there was no significant interference from above therapeutic levels of likely concomitant medications. Results on patient samples from the teicoplanin FPIA were highly correlated with both a high-performance liquid chromatography (HPLC) method (FPIA = 1.032 x HPLC + 2.79, r = 0.979, n = 203) and the reference teicoplanin microbiologic assay method (orthogonal regression; FPIA = 1.111 x bioassay + 2.107, r = 0.969, n = 1014). A version of the teicoplanin FPIA for use with a modular clinical research FPIA analyzer showed comparable performance in all respects to the automated assay.

Fluorescence Polarization Immunoassay↗
PubMed1991

A case of granulomatous hepatitis after intravesical bacillus Calmette-Guerin administration.

A 61-year-old man received intravesical bacillus Calmette-Guerin (BCG) as treatment for superficial bladder carcinoma. High spiking relapsing fevers began 39 days after the initial treatment. A liver biopsy revealed noncaseating granuloma. Deoxyribonucleic acid hybridization of the bone marrow was positive for Mycobacterium tuberculosis complex. Pressure exerted to instill the BCG may have favored dissemination.

Administration, Intravesical↗
PubMed1987

Diagnostic value of a single, pre-treatment Widal test in suspected enteric fever cases in the Philippines.

101 patients with a clinical suspicion of typhoid or paratyphoid (enteric) fever admitted to San Lazaro Hospital, Manila, Philippines, were studied by bacteriological culture of blood, rectal swab, urine and duodenal string capsule; 35 also had bacteriological culture of bone marrow aspirate. 44 of the patients were culture-confirmed as having enteric fever; the remainder were classified as non-enteric fever cases. Analysis of the pretreatment Widal agglutination titres of all patients revealed that using as a diagnostic criterion an antibody titre of greater than or equal to 1:80 to the O antigen of Salmonella typhi yielded a test specificity of 100%, although the corresponding sensitivity was only 64%. The sensitivity of the test could be increased to 80% by using different cut-off values for titres to flagellar antigens, but this concomitantly decreased the test specificity from 100 to 82%. The data indicate that a single pretreatment Widal test in suspected enteric fever cases is of definite diagnostic value, but that the results must be interpreted with caution and foreknowledge of the test's shortcomings and limitations.

Adolescent↗
PubMed1987

In vitro drug response of Plasmodium falciparum in the Philippines: increased resistance to amodiaquine.

A long term study was carried out at San Lazaro Hospital, Manila, Philippines, monitoring the in vitro response of Plasmodium falciparum to chloroquine, amodiaquine, mefloquine, and quinine. The in vitro effective dose giving 50% inhibition of schizogony was: 0.68 X 10(-6) M/liter blood for chloroquine; 0.18 X 10(-6) for amodiaquine; 0.2 X 10(-6) for mefloquine; and 1.12 X 10(-6) for quinine. The percent of isolates determined to be resistant in vitro was 85.2% for chloroquine, and 1.2% for both mefloquine and quinine. These figures were relatively unchanged over the course of 3 years studied. The in vitro resistance rate to amodiaquine increased from 5.1% in 1982 to 22.2% in 1984.

Amodiaquine↗
PubMed1985

Studies of resistance to chloroquine, quinine, amodiaquine and mefloquine among Philippine strains of Plasmodium falciparum.

One hundred cases of slide-confirmed Plasmodium falciparum malaria admitted to the San Lazaro Hospital, Manila, Philippines were screened for in vitro resistance to chloroquine, quinine, amodiaquine and mefloquine using the microtechnique. 59 of the 100 primary parasite isolates produced schizonts, whereas the remaining 41 isolates did not. 51 of the 59 isolates tested were resistant in vitro to chloroquine and eight were sensitive. In contrast, three of the primary isolates were resistant to quinine, three showed resistance to amodiaquine and four were mefloquine-resistant. 43 of the strains judged chloroquine-resistant in vitro were fully in vitro sensitive to amodiaquine, quinine and mefloquine. One chloroquine-resistant isolate was also resistant to quinine alone. Three isolates that were resistant to chloroquine were also resistant to amodiaquine. An additional three were cross-resistant to chloroquine and mefloquine. A single isolate was found to be resistant to chloroquine, quinine and mefloquine and another was cross-resistant to chloroquine, quinine and amodiaquine. All strains demonstrating in vitro resistance to amodiaquine, quinine or mefloquine also showed in vitro resistance to chloroquine. The parasites in 22 patients showed in vivo resistance to chloroquine therapy. 86% were of the R1 type, 9% were R2 and 5% R3. All 22 patients demonstrating in vivo resistance to chloroquine showed in vitro resistance.

Amodiaquine↗
PubMed1983

Malaria at San Lazaro Hospital, Manila, Philippines, 1979-1981.

Results are presented from the 1,000 slide-confirmed malaria cases seen during the period August 1979-September 1981 at San Lazaro Hospital, in Manila, Philippines; 56% were caused by Plasmodium falciparum, 38% by P. vivax, 6% were mixed infections, and 0.1% by P. malariae. The overall case fatality rate was 1%, all due to P. falciparum. Cerebral involvement occurred in 7% and the case fatality rate was 20% compared to a case fatality rate of 0.2% among P. falciparum cases without cerebral involvement. In vivo chloroquine-resistant P. falciparum was seen in 4% of the cases, but of those treated in 1981, 9% of the cases showed resistance. The distribution of chloroquine-resistant cases by province in the Philippines is shown, with resistance being reported for the first time from Isabela, Bulacan, Zambales, Rizal and Bataan provinces. Diagnostic, clinical, and epidemiologic aspects of the cases are discussed, as well as the trend in malaria cases over the last 20 years.

Adolescent↗
PubMed1983

Chloroquine resistant Plasmodium falciparum: effect of rabbit serum and incubation time on the in vitro (microtechnique) prediction of in vivo resistance.

A study of chloroquine resistance of 54 isolates of Plasmodium falciparum is reported. Sixty-four percent of the isolates tested produced schizonts in vitro (micro-technique), whereas the remaining 36 percent did not. The accuracy of the in vitro test to predict in vivo resistance was increased when the primary parasite isolates were cultured in the presence of rabbit serum and when the cultures were allowed to incubate for more than 48 hours. Thirteen isolates of P. falciparum that showed in vitro resistance were confirmed in vivo resistant. Eleven of these cases were identified as R-I and two as R-II. Only one case of in vivo resistance (R-II) was observed among the 19 isolates that failed to produce schizonts in vitro.

Animals↗
PubMed1982

Chloroquine and quinine resistant Plasmodium falciparum on the island of Mindoro, Philippines, 1982.

A field study was conducted on the island of Mindoro, Republic of the Philippines in which over 800 persons were screened for malaria and approximately 8% were found positive. The in vitro microtechnique was used to test for sensitivity to chloroquine, amodiaquine, mefloquine and quinine in 20 slide-confirmed P. falciparum cases. Sixteen of these cases were also followed for in vivo chloroquine sensitivity. Four cases showed in vitro resistance to chloroquine; 2 also showed resistance to quinine. All showed in vitro sensitivity to mefloquine and amodiaquine. The results of in vivo test were consistent with either a sensitive (S) or R-1, resistant response to chloroquine. Taken together, the in vitro and in vivo chloroquine tests indicate 4 cases of chloroquine resistance at the R1 level.

Chloroquine↗
PubMed1982

Cerebral malaria at San Lazaro Hospital, Manila, Philippines.

Forty cases of cerebral Plasmodium falciparum malaria seen at San Lazaro Hospital, Manila, Philippines from 1979-1981 were reviewed. These cases represented 7% of all Plasmodium falciparum cases seen during this period. All of the patients had fever and headache, 73% confusion, 70% chills, 68% jaundice or abdominal pain, 60% sweats. Findings more frequent in the fatal compared to the non-fatal cases were: the presence of schizonts in the peripheral smear, oliguria, coma, convulsions, urinary incontinence, jaundice, pulmonary symptoms and vomiting. Fatal cases were less likely to be clinically diagnosed as malaria and more likely to be diagnosed as hepatitis than malaria. The treatment and management of these cases is discussed.

Adolescent↗