Biomedical subjects

H Morales

Publications and source records attributed to H Morales.

At least 19 recordsLinked to original sources

PubMed2007

Patulin accumulation in apples by Penicillium expansum during postharvest stages.

AIMS: The aim of this study was to assess the opportunities of Penicillium expansum to develop and produce patulin in apples during cold storage and in the steps prior to processing of apple products. METHODS AND RESULTS: Two lots of apples var. Golden with different ripeness degree were used. Half of each lot was fungicide treated. Apples were inoculated with P. expansum and stored at 1 degrees C for 6 weeks. The extent of lesions and patulin accumulation both at the end of cold storage and after 3 days at 20 degrees C were assessed. Short storage at 20 degrees C aimed to simulate the transport and storage steps at room temperature before processing. Lesion size significantly increased during the storage at 20 degrees C. An interaction between fungicide treatment and ripeness degree was found; efficiency of fungicide treatment was higher for ripe apples. Although lesions were evident after cold storage, no patulin was detected. Patulin was detected only when fruits were further stored at 20 degrees C. Neither ripeness degree nor fungicide treatment affected patulin accumulation. CONCLUSIONS: Cold storage periods of 6 weeks do not lead to patulin accumulation. SIGNIFICANCE AND IMPACT OF THE STUDY: Shortening preprocessing times at warm temperatures would result into a reduction in patulin content at initial steps of fruits entering the processing plants.

Food Handling↗

PubMed2006

Patulin distribution in Fuji and Golden apples contaminated with Penicillium expansum.

This work assesses the extent of patulin contamination in Penicillium expansum-infected apples stored at room temperature for short periods of time and its relationship with apple variety (Golden or Fuji), degree of ripeness and size of lesions. Inoculated apples were incubated at 20 degrees C. Patulin was determined in both sound and decayed tissue from cylindrical samples taken around the lesions and cut into 0.5-cm thick sections. Higher accumulation of patulin occurred in Golden apples, with less ripened apples showing higher concentrations. Total accumulated patulin was similar or higher in 4-cm compared to 2-cm lesioned apples, although a decrease in patulin concentration was observed in older lesion sections. Patulin accumulation occurred over a short period of time at room temperature, thus the stand-by period before processing should be minimised. Of total patulin, 2-6% migrated to the surrounding sound tissue, thus trimming tissue around the rotten part may be a good preventive practice for apple derivative production.

Food Analysis↗

PubMed2004

Farmers' perceptions, knowledge, and management of coffee pests and diseases and their natural enemies in Chiapas, Mexico.

Small farmers' perceptions of coffee Coffea arabica L. herbivores and their natural enemies, how those perceptions relate to field infestation levels, and pest management practices being implemented by members from two organic and nonorganic coffee grower organizations in the Soconusco region, southeastern Mexico, were analyzed through an interview survey, diagnostic workshops, and field sampling. The terms pest, disease, and damage were commonly used as synonyms. The major phytophagous species, as perceived by the interviewees, were Hypothenemus hampei (Ferrari), and to a lesser extent the fungi Corticium koleroga Cooke (Höhnel) and Hemileia vastatrix Berkeley & Broome. Among the nonorganic farmers, other nonpest-related constraints were regarded as more important. Awareness of the existence of natural enemies was low, despite more organic farmers have used the ectoparasitoid bethylid Cephalonomia stephanoderis Betrem against H. hampei. Labor supplied by household members was most frequent for pest control; only organic farmers exchanged labor for this purpose. The levels of infestation by H. hampei, Leucoptera coffeella Guérin-Méneville, and C. koleroga were lower within the organic coffee stands. However, a low effectiveness for pest control was commonly perceived, probably due to a feeling, among the organic farmers, of a low impact of their pest management extension service, whereas a lack of motivation was prevalent among the nonorganic farmers, shown by a concern with their low coffee yields and the emigration of youth. The importance of understanding farmers' perceptions and knowledge of pests and their natural enemies and the need for participatory pest management approaches, are discussed.

Agriculture↗

PubMed2003

Evolution of the immunomodulatory role of the heat shock protein gp96.

In mammals, certain heat shock proteins (hsps) participate in specialized responses to stressors associated with pathogens or tumors, and as such, act as agents of immune surveillance interacting with both innate and adaptive immunity. We are investigating the conservation of this role throughout the class of vertebrates. We have shown that in Xenopus as in mammals, gp96, the major resident of the endoplasmic reticulum, generates MHC-restricted thymus-dependent immunity in vivo and CR in vitro against minor histocompatibility (H) antigens. By as yet unclear mechanisms that may involve classical MHC-unrestricted cytotoxic CD8+ T cells, gp96 also elicits peptide-specific responses against MHC-class I-negative tumors in adult frogs that may involve cytotoxic NK, MHC-unrestricted CD8+ T and NK/T cells. In naturally MHC class I-deficient but immunocompetent Xenopus larvae, gp96 also generates an innate type of anti-tumor response that is independent of chaperoned peptides. Finally, in a subset of Xenopus sIgM+ B cells, a substantial fraction of gp96 is directed to the cell surface by an active process that is upregulated by bacterial stimulation. This may allow gp96 to access the extracellular compartment without necrosis. Given the dual abilities of gp96 to chaperone antigenic peptides and to modulate innate immune responses, we propose that stimulated B cells that are up-regulating surface gp96 can directly interact with antigen presenting cells (APC) and/or T helper (Th) cells to trigger or amplify immune responses.

Adjuvants, Immunologic↗

PubMed1999

Pyruvate prevents peroxide-induced injury of in vitro preimplantation bovine embryos.

The impact of oxidative stress on the in vitro development of bovine embryos in synthetic oviduct fluid medium (mSOF) was assessed by using H2O2 as a stress inducer. In a preliminary experiment, a chemiluminescent method was used to measure the antioxidative capacity of the mSOF culture medium. Pyruvate was the mSOF component displaying the highest H2O2 degrading ability. Essential and nonessential amino acids also significantly reduced the H2O2 concentration, whereas lactate and glutamine were ineffective. The effect on further development of a short exposure of zygotes, 9-16-cell stage embryos and blastocysts to 0 M; 10(-7) M ; 10(-6) M, and 10(-5) M H2O2 in pyruvate-free mSOF was evaluated. Developmental rates of the H2O2-treated zygotes to the 5-8-cell or blastocyst stages and survival of H2O2-treated blastocysts were reduced in a dose-dependent manner whereas the 9-16-cell embryos were unaffected by those treatments. Blastocysts treated with H2O2 also tended to have lower numbers of bisbenzimide-stained nuclei and showed increased nuclear fragmentation. Including pyruvate in the mSOF culture medium during a 10(-5) M H2O2 pulse highly reduced the H2O2 concentration as measured by chemiluminescence and improved zygote and blastocyst development, but failed to prevent blastocyst nuclei degradation. These experiments suggest that bovine embryos show developmental change in sensitivity to exogenous H2O2, the 9-16-cell embryos being more resistant than zygotes and blastocysts and that H2O2 and its toxic effects can be attenuated by including pyruvate in the medium.

Animals↗

PubMed1997

[Comparison of extra renal potassium management in hypertensive, diabetic and normal subjects].

BACKGROUND: Sodium and potassium ions are involved in the regulation of blood pressure and the genesis of hypertension. AIM: To assess internal potassium balance, as a measure of sodium pump activity, in subjects with essential hypertension and diabetic patients. PATIENTS AND METHODS: Eleven hypertensive subjects, 5 non-insulin-dependent diabetics and 16 age matched controls were studied. An acute oral load of 0.8 mEq/Kg body weight of KCl was administered and blood samples were drawn every 30 min thereafter, until 120 min, to measure plasma K+ levels. Urinary K+ excretion during this period was also measured. In eight hypertensive patients, the test was repeated after two week of supplementation with 60 mEq/day of KCl. The maximal increase in plasma potassium levels and the time required to achieve the maximum concentration was recorded. RESULTS: All patients had normal serum creatinine levels. Mean fasting blood glucose of diabetic patients was 133 +/- 15.1 mg/dl. No difference between patients and controls in maximal increase plasma potassium increase, was observed. In hypertensive patients the lapse to achieve the maximal potassium concentration was longer than in controls. After the period of potassium supplementation in hypertensive patients, there was a significant increase in basal plasma K+ levels and the temporal pattern of plasma potassium increase was similar to that of controls. Between 63 and 68% of retained K+ load was translocated to the intracellular space at 120 min in all study groups. CONCLUSIONS: Internal potassium balance is not significantly altered in subjects with essential hypertension or in non-insulin-dependent diabetics.

Adult↗

PubMed1993

[Multiple splenic abscesses. Report of 2 cases].

Splenic abscesses are infrequent and usually associated to sepsis and immunodepression. The diagnosis is commonly made in the necropsy. We report two cases of multiple splenic abscesses in type II diabetic patients that were diagnosed by ultrasound. Both patients were successfully managed with surgery (drainage of left subphrenic space in one and splenectomy in the other) and antimicrobial agents.

Abscess↗

PubMed1991

Analysis of class II MHC structure in thymic nurse cells.

During the course of thymocyte maturation, the processes of positive selection and tolerance induction are mediated by interactions between thymocyte T-cell receptors and MHC molecules on thymic stromal cells. The means by which these seemingly contrary processes can be mediated by interactions between the same molecules has long been a source of controversy. One idea which has been put forward is that the MHC molecules in different microenvironments of the thymus are not the same. We have tested this hypothesis by examining class II transcripts derived from thymic cortical epithelial cells known as thymic nurse cells, reasoning that alternative splicing of primary transcripts might give rise to a positively selecting MHC molecule. However, we found no evidence for alternative splicing of these transcripts. These results are presented and discussed with regard to implications for possible mechanisms of positive selection.

Amino Acid Sequence↗

PubMed1991

[Insulin sensitivity: absence of sexual differences when expressed as a function of lean body mass].

The hyperinsulinemic, euglycemic clamp technique was used to test the hypothesis that--when expressed per kilogram of lean body mass--there is a sex-difference in peripheral insulin-mediated glucose disposal (M), as proposed in the literature. Lean body mass was assessed with tetrapolar bioelectric impedance analysis. We studied 15 normal subjects (volunteers with normal glucose tolerance and body mass indices between 20-25 kg/m2) of both sexes, 9 women and 6 men, of 2 age-groups, 20-30 year-old and 40-50 year-old. Men and women were similarly aged (33.3 +/- 3.8 and 33.3 +/- 3.8 years, respectively). Body mass indices were similar in both sexes (22.5 +/- 0.6 in women and 23.6 +/- 0.7 in men, NS) but percentages of fat mass were not (29.4 +/- 1.2 in women and 20.6 +/- 1.6 in men, p less than 0.001). As no difference in M (mg of glucose metabolized per kilogram of body weight per minute) between age-groups was found (6.4 +/- 0.8 and 6.8 +/- 1.2 mg/kg/min, NS) the data from these 2 age-groups were pooled. When M values obtained in both sexes were compared no differences were found (7.1 +/- 1.5 mg/kg/min in women and 6.3 +/- 0.6 in men, NS). Similarly, when M was expressed in function of the prevailing insulin levels attained during steady-state, M/l, no differences were disclosed (8.98 +/- 2 mg/kg/min/microIU insulin in women and 7.8 +/- 1.2 in men, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

[Diabetes mellitus in chronic alcoholic liver damage].

We performed an oral glucose tolerance test and measured serum insulin levels in 38 patients with chronic alcoholic liver damage. A diabetic curve was obtained in 34% of subjects both obese and non obese. Insulin levels were elevated in comparison with normal subjects in all patients. The Turner index [(serum insulin x 100)/(blood sugar--30]) was lower than normal at all points of the GTT, suggesting a decreased insulin secretion in relation to serum glucose level. Blood glucose level at 120 min was correlated to age, serum bilirubin and prothrombin time. Thus, chronic liver damage is a risk factor for diabetes mellitus. The alteration of carbohydrate metabolism is correlated to the severity of liver disfunction. The initial pathogenic factor may be hyperinsulinism and resistance to insulin, followed by decreased secretion of the hormone.

Analysis of Variance↗

PubMed1989

[Intensive nutrition in ulcerative colitis. Influence on postoperative morbimortality].

Out of 103 consecutive patients with ulcerative cholitis, 37 required surgery. We compared perioperative morbidity and mortality in 18 patients receiving intensive nutritional care with 9 controls. An increase in serum albumin form 2.8 +/- 0.5 to 3.4 +/- 0.4 mg/dl (p less than 0.01) and lymphocytes from 1210 +/- 614 to 1736 +/- 770 (p less than 0.05) was observed in the first group, but not in the second. No deaths, shorter hospital stay and fewer complications were observed in the first group. We conclude that intensive nutritional care should be routinely used in patients with severe ulcerative cholitis requiring surgery.

Adult↗

PubMed1989

[Metabolic control of non insulin dependent diabetes mellitus in surgery].

We followed 50 type II diabetic patients undergoing various types of surgical procedures. Control of blood sugar was evaluated as percent of tests within an acceptable limit defined as 160 mg/dl in the preoperative period, 80-240 mg/dl in the early postoperative period and 80-120 mg/dl thereafter. Adequate control was present in 56% of tests in the first period, 95% in the second and 70% in the third. Only 2 subjects experienced hypoglycemia with no sequelae. No cases of ketoacidosis or hyperosmolar coma were observed. Overall mortality was 2% and complications included electrolyte alterations in 8%, acid base disturbance in 4% and infection in 16%. Thus, adequate metabolic control and low morbidity and mortality are possible in patients with type II diabetes undergoing surgery.

Adult↗

PubMed1982