Biomedical subjects

H M Müller

Publications and source records attributed to H M Müller.

111 records · Page 7Linked to original sources

PubMedDate not supplied

[Measures for lessening the mycotoxin formation and concentration in feed].

Procedures for lowering the production of mycotoxins in cereals before harvest are not available. Breeding of cereal varieties which are resistant to fusaria is a promising approach. Development of storage fungi and fusaria after harvest can be inhibited by drying with warm or ambient air, refrigerated storage, chemical preservation (e.g. by propionic acid, urea), and airtight storage. For the quantitative determination of fungal growth in feedstuffs a chemical indicator such as ergosterol must be determined. A preservation procedure can be regarded as effective only if it is able to inhibit mold growth completely. This is concluded from the observation that an initial toxin-free phase of growth which has been found in mold cultures with liquid medium could not be detected during refrigerated storage of wheat. Under these conditions the production of ochratoxin A and other mycotoxins by Penicillium strains started simultaneously with the production of ergosterol. For an effective ambient air drying of cereals the depth of the whole bulk and the velocity of air must afford complete drying within 8-10 days. During refrigerated storage of cereals maximal storage periods which depend on moisture content and temperature should not be exceeded. Maximal storage periods based on ergosterol determinations are described for wheat with an initial moisture content between 18 and 26% and storage temperatures of 4 and 10 degrees C. The effect of propionic acid concentration on the development of molds is described, recommendations for selecting optimal acid dosages are given.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMedDate not supplied

Determination of ergosterol in cereals, mixed feed components, and mixed feeds by liquid chromatography.

A sensitive, rapid, reproducible, and reliable liquid chromatographic (LC) method is described for determination of ergosterol in feedstuffs. The sample is saponified directly and the saponified mixture is extracted with n-hexane. Ergosterol is determined without further purification or cleanup steps by using a liquid chromatograph with a 250 X 4.6 mm column packed with LiChrosorb Si 60, 5 microns, and a high pressure column prefilter. The ultraviolet detector is set at 282 nm. The limit of detection was 0.1 ppm; recovery ranged between 96.7 and 102.2%. Diode array technology is used for identification and peak purity control. Under strong UV irradiation (254 nm) and oxygen or nitrogen atmosphere ergosterol was converted almost quantitatively to ergocalciferol. Under the described conditions of the method, ergosterol proved to be stable. Ergosterol was determined in cereals, mixed feeds (e.g., for swine and poultry), and their components of plant and animal origin. It was not found in carcass meal, meat-and-bone meal, citrus pulps, or molasses; only traces were detected in fish meal.

Animal Feed↗

PubMedDate not supplied

Prevalence and serological manifestation of hepatitis C virus infection in patients with hepatitis non-A, non-B: a follow-up study.

OBJECTIVES: Sera of patients with acute hepatitis non-A, non-B prospectively followed for a mean of 11.4 years (range 9 to 15 years) were assayed for anti-hepatitis C virus (HCV) by first- and second-generation enzyme-linked immunosorbent assay (ELISA) and second-generation recombinant immunoblot assay (RIBA) to study the patterns of antibody response in relation to the outcome of disease. METHODS: From 1974 through 1981, 112 patients with acute hepatitis non-A, non-B were enrolled in a prospective study. Sera of 45 patients taken during the acute phase of hepatitis, as well as taken during follow-up in 1983 and 1990 were still available for evaluation. Sera were assayed by first- (ELISA-1) and second-generation (ELISA-2) anti-HCV ELISA, second-generation RIBA (RIBA-2) and HCV RNA by RT-polymerase chain reaction (PCR). RESULTS: Based on anti-HCV seropositivity by RIBA-2 in acute hepatitis and/or during follow-up, a total of 22/45 patients with HNANB (48.8%) were considered to have confirmed HCV infection. By ELISA-1, 11/22-patients with HCV infection (50%) were positive for anti-HCV within 6 weeks of the onset of illness, 18/22 sera (82%) were reactive by ELISA-2. Confirmation by RIBA-2 was obtained in 12 (55%) cases, while one additional patient was RIBA-2 indeterminate. In 1983, a disappearance of anti-HCV tested by RIBA-2 was observed in 7/12 resolved patients but in none of the patients with chronic hepatitis (p = 0.0018) while loss of anti-HCV was observed in 2/12 cases with resolved hepatitis and none with chronic hepatitis by ELISA (not significant). In 1990, all patients with chronic hepatitis were still positive by either ELISA or RIBA-2 but 9/12 (75%), 6/12 (50%) and 10/11 (91%) patients with resolved hepatitis had lost anti-HCV seropositivity tested by ELISA-1 (p = 0.0004), ELISA-2 (p = 0.0124) or RIBA-2 (p < 0.0001), respectively. Mostly, RIBA-2 reactivity was lost prior to ELISA-2 reactivity during follow-up. Rates of antibody loss as detected by ELISA-1, ELISA-2 and RIBA-2 were 4.1, 2.9 and 5.8 per 100 person years, respectively. CONCLUSIONS: This study shows that the continuing presence of HCV is necessary to maintain anti-HCV seropositivity. In contrast, anti-HCV reactivity is progressively lost over time in resolved patients. In addition, albeit more specific, the RIBA-2 is less sensitive than the ELISA and RIBA seroconversion to negative seems to be the earliest serological marker of a resolved HCV infection.

Adult↗