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I Bosch

Publications and source records attributed to I Bosch.

26 records · Page 2Linked to original sources
PubMed1987

Determination of alpha-alkyl-alpha-amino acids and alpha-amino alcohols by chiral-phase capillary gas chromatography and reverse-phase high-performance liquid chromatography.

The enantiomeric resolution by fused-silica capillary gas-liquid chromatography (GLC) of non-protein DL-alpha-alkyl-alpha-amino acids of the structure H2NCR1R2COOH (R1 = alkyl, R2 = alkyl, alkaryl) was investigated by using chiral [L-valine-tert.-butylamide, linked to a statistical polymer of dimethylsiloxane and (2-carboxypropyl)methylsiloxane, Chirasil-L-Val, and XE-60-S-Val-S-alpha-phenylethylamide] and non-chiral (methylphenylcyanopropylvinylpolysiloxane, CP-Sil-19 stationary phases. To evaluate the resolution coefficients, N-acylamino acid n-propyl esters (acyl = acetyl, propionyl, trifluoroacetyl, pentafluoropropionyl, heptafluorobutyryl) and diastereomeric esters with S(-)-2-methyl-1-butanol, S(+)-2-butanol and S(+)-2-octanol were used. Although alpha-alkyl-alpha-amino acids in general gave lower resolution coefficients than the enantiomers of protein amino acids, most alpha-alkyl-alpha-amino acids could be resolved by using suitable derivatization procedures and, preferably, isothermal conditions. In addition, a number of DL-alpha-alkyl-alpha-amino acids could be separated by ligand-exchange chromatography (L-hydroxyproline/Cu2+) by both thin-layer chromatography (Chiralplate) and high-performance liquid chromatography (HPLC) (Nucleosil Chiral-1). Further, a standard mixture composed of fifteen alpha-amino acids and eleven alpha-amino alcohols could be completely separated by C18 HPLC after derivatization with o-phthaldialdehyde-2-mercaptoethanol (OPA-2-ME). The time and temperature dependences of the relative fluorescence of the adducts were investigated kinetically.

Amino Acids↗
PubMed1978

Eosinophilic granulocytes in cerebrospinal fluid: analysis of 94 cerebrospinal fluid specimens and review of the literature.

Eosinophilic granulocytes in the CSF were observed in 94 of approximately 10,000 qualitative cytologic preparations. Those cases of eosinophilia which occurred in the context of a parasitic disease or a puncture-related hemorrhage were excluded. CSF eosinophilia exceeding 1% was found in 57.5% of the cases and 5% in 23.5%. Increased cell counts were observed in 67.7% of the cases; elevated CSF protein values, in 68% to 73%; blood eosinophils, in 10.4%. There was no reason to suspect a relationship between these findings and the number of eosinophils in the CSF.--Fifty-two percent of the cases involved inflammatory diseases of the nervous system; the 18 cases of abacterial inflammation of unknown etiology were particularly striking. In the remaining cases, eosinophils were found in conjunction with cerebral ischemia and hemorrhage, with tumors, and in a relatively high percentage of children (21%). The frequency of occurrence with drained or undrained hydrocephalus was striking. A review of the pathophysiological function of eosinophils indicated that revived or corpuscular antigens were present in all cases of CSF eosinophilia in which an eosinophilic reaction was induced. Nothing can be said at this time, however, concerning the classification of the antigens.

Cell Count↗
PubMedDate not supplied

Diagnosis of malaria by acridine orange fluorescent microscopy in an endemic area of venezuela.

Fluorescent (acridine orange) microscopical examination of capillary centrifuged blood (quantitative buffy coat [QBC] analysis) and Giemsa stained thick blood smears (GTS) were compared for diagnosis of malaria in blood specimens from adults living in malaria transmission areas of the States of Bolivar and Amazonas in southeastern and south Venezuela, respectively. Of a total of 198 GTS examined, 95 subjects (48%) showed parasitaemia. Among the 95 blood films with a positive GTS, 94 were judged positive by the QBC. However, positive QBC tubes were found in 29 out of 103 blood specimens with a negative GTS. Thus, relative to a GTS standard, the sensitivity and specificity of the QBC-test was 99.2% and 72%, respectively. Young trophozoites of Plasmodium vivax and P. falciparum could not be distinguished with certainty. It is confirmed that the QBC offers many advantages compared with the standard diagnosis of malaria parasites, specifically in the speed of staining and ease of interpretation. However, in places where P. falciparum and P. vivax occur, species and stage differentiation should be confirmed with the GTS.

Acridine Orange↗