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Biomedical subjects

M L Herrera

Publications and source records attributed to M L Herrera.

6 recordsLinked to original sources
PubMed2001

Effect of cooling rate on nucleation behavior of milk fat--sunflower oil blends.

The effect of cooling rate on the crystallization behavior of mixes of high-melting milk fat fraction (HMF) and sunflower oil (SFO) was studied by following nucleation with laser-polarized turbidimetry. The initial crystals were photographed, and their thermal and polymorphic behaviors, as well as chemical composition, were investigated by calorimetry, X-ray diffraction, and capillary gas chromatography. Activation energies of nucleation were calculated using the Fisher-Turnbull equation. Despite small differences in Mettler dropping points for different ratios of SFO to HMF, induction times were significantly different between samples and were shorter at a slow cooling rate for the same supercooling. Rapidly cooled samples required more time at crystallization temperature to crystallize than slowly cooled samples because molecular organization prior to nuclei formation took place under different conditions. Regardless of cooling rate or composition, all crystals were in the beta' polymorph. However, morphology, thermal behavior, and chemical composition showed differences with cooling rate. Activation free energies of nucleation were of the same order of magnitude as those published for hydrogenated SFO.

Crystallization↗
PubMed1997

Comparative trial of 3 days of azithromycin versus 10 days of clarithromycin in the treatment of children with acute otitis media with effusion.

The authors compared the efficacy, safety and tolerance of azithromycin and clarithromycin in pediatric patients with acute otitis media. A randomized, open clinical trial was performed comparing azithromycin and clarithromycin in children aged 6 months to 12 years of age with acute otitis media with effusion. Patients were allocated to azithromycin at 10 mg/kg once daily for 3 days or to clarithromycin at 15 mg/kg day divided into two equal doses for 10 days. Clinical examinations and tympanometric evaluations were performed at baseline, day 3-5, day 10-14, day 28-30 and day 50-60. Tympanocentesis fluid cultures were collected at enrollment and urine and blood samples were obtained at baseline and day 10-14. Of 100 patients enrolled, 97 were considered evaluable. The most common middle ear pathogens were Streptococcus pneumoniae (60%), Haemophilus influenzae (15%) and Staphylococcus aureus (13%). Fifty patients (100%) treated with azithromycin and 45 (95.7%) patients treated with clarithromycin had a satisfactory clinical response. Rates of persistence of middle ear effusion and possible drug related side effects were comparable. Based on the efficacy and safety results, azithromycin for 3 days and clarithromycin for 10 days are considered to represent an attractive alternative for the treatment of children with acute otitis media.

Anti-Bacterial Agents↗
PubMed1986

[Morphological changes induced by ampicillin in Campylobacter].

Morphologic changes in Campylobacter fetus ssp. jejuni were evaluated as cultivated on thioglycollute broth, containing minimum of 0.1, 1.3 and 10 Ampicillin minimal inhibitory concentration (MIC). During the first four hours of incubation, no changes occurred in the presence of 0.1 MIC; but with the rest of the ampicillin doses, even at the first hour, a proportion larger than 5% of filament-policurved forms was found, and it increased with the incubation time. The greatest number of altered bacteria was found with the use of 10 MIC. No other morphologic changes were observed.

Ampicillin↗
PubMed1985

[Campylobacter fetus ssp. jejuni, Aeromonas hydrophila, helicoidal bacteria and coronavirus in the murine intestine].

Intestinal contents of 28 laboratory-bred white mice and 6 wild-caught rats were extracted and observed with phase-contrast and transmission electron microscopy; cultures were made in Butzler agar and aeromonas, incubated in microaerobiosis, at 37 degrees C for 5 days. In three mice and two rats, helicoidal bacteria were observed, with 8 to 11 periplasmic fibers and terminal branches of 8 to 11 structures, similar to flagella. In one of the rats, coronavirus-like particles were observed. Campylobacter fetus ssp. jejuni was isolated in cultures from two mice and Aeromonas hydrophila from two rats.

Aeromonas↗