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Biomedical subjects

M Cervantes

Publications and source records attributed to M Cervantes.

At least 19 recordsLinked to original sources
PubMed2006

The effect of feeding low-phytate barley-soybean meal diets differing in protein content to growing pigs on the excretion of phosphorus and nitrogen.

An experiment was conducted with growing pigs to determine the excretion of P and N in 4 barley-based diets formulated to contain 18 or 15% CP by using a normal barley (NB) or a low-phytate barley (LPB). The NB contained 0.31% total P and 0.19% phytate P; the LPB contained 0.32% total P and 0.01% phytate P. The diets were supplemented, when so required, with lysine, methionine, threonine, and tryptophan to meet their apparent ileal digestible supplies according to the NRC (1998). The diets containing NB were supplemented with inorganic P to meet the NRC (1998) recommendation for available P (0.23%). The diets containing LPB were not supplemented with inorganic P because these contained sufficient available P (0.27%). Eight barrows with an average BW of 20.9 kg were assigned to the 4 dietary treatments according to a repeated 4 x 4 Latin square design. The diets were fed at a rate of 2.5 times the ME requirement for maintenance. The barrows were fed twice daily, at 0800 and 1500, equal amounts each meal. Water was added to the feed at a ratio of 2.5:1. Each experimental period consisted of a 7-d adaptation period followed by a 5-d collection of feces and urine. The substitution of NB with LPB decreased (P < 0.001) the total P excretion by 38 and 43% for the 18 and 15% CP diets, respectively. Reducing the CP content from 18 to 15% decreased (P < 0.001) the N excretion by 29 and 32% for the NB and LPB diets, respectively. With the reduction in CP content, there was a decrease (P < 0.001) in the amount of N retained. The N:P ratio in manure of pigs fed the LPB diets was greater (P < 0.001) than from pigs fed the NB diets. These data indicate that P and N excretion can be greatly reduced by substitution of NB by LPB, and also by the reduction of the CP content, in diets for growing pigs.

Animal Feed↗
PubMed2005

Effect of phytase supplementation to diets for weanling pigs on the digestibilities of crude protein, amino acids, and energy.

Four experiments were conducted with weanling pigs fitted with a simple T-cannula at the distal ileum, to determine the effect of phytase supplementation to four diets on the apparent ileal digestibilities (AID) of CP and AA, and the apparent total-tract digestibilities (ATTD) of CP and DE. Phytase (Natuphos, DSM Food Specialties, Delft, The Netherlands) was supplemented at rates of 0, 500 or 1,000 FTU/kg to the four diets. A 20% CP (as-fed basis) corn-soybean meal diet was used in Exp. 1; a 20% CP wheat-soybean meal diet in Exp. 2; a 20% CP wheat-soybean meal-canola meal diet in Exp. 3; and a 19% CP barley-peas-canola meal diet in Exp. 4. In each experiment, six barrows, fitted with a simple T-cannula at the distal ileum, were fed the basal plus phytase-supplemented diets according to a repeated 3 x 3 Latin square design. Each experimental period comprised 14 d. The piglets were at fed 0800 and 2000 daily, equal amounts for each meal, at a daily rate of at least 2.4 times the maintenance requirement for ME. Feces were collected from 0800 on d 8 until 0800 on d 12 of each experimental period. Ileal digesta were collected from 0800 to 2000 on d 12, 13, and 14. Chromic oxide was used as the digestibility marker. The average initial and final BW (average of all experiments) were 7.9 and 16.5 kg, respectively. Phytase supplementation did not improve the AID of CP and AA in Exp. 1, 2, and 4; however, there were improvements (P < 0.05) or tendencies (P < 0.10) toward improvements in the AID of CP and AA or the ATTD of CP and the content of DE with phytase supplementation in Exp. 3. These results suggest that the AA response factor to microbial phytase supplementation depends on diet composition.

6-Phytase↗
PubMed2005

Effect of phytase supplementation to a low- and a high-phytate diet for growing pigs on the digestibilities of crude protein, amino acids, and energy.

Supplementation of microbial phytase usually improves the digestibility and utilization of phosphorus in feedstuffs of plant origin. The effect of phytase supplementation on the digestibilities of AA also has been examined, but the results have been inconsistent. This study was carried out to determine the effect of phytase (Natuphos) supplementation, at a rate of 2,000 phytase units/kg, to two basal diets on the apparent ileal digestibilities (AID) of GE, CP, and AA, and on the apparent total-tract digestibilities (ATTD) of CP and GE. The basal diets contained 18% CP and were formulated (as-fed basis) to contain either a low (0.22%) or high content (0.48%) of phytate P. The high-phytate diet contained 20% rice bran, which is a rich source of phytate and has low intrinsic phytase activity. Eight barrows (average initial BW = 40.6 kg), fitted with a simple T-cannula at the distal ileum, were fed the four diets according to a replicated 4 x 4 Latin square design. The pigs were fed twice daily at 0800 and 2000, equal amounts each meal, at a rate of 2.4 times the daily maintenance requirement for ME. Each experimental period comprised 14 d. Ileal digesta were collected from 0800 to 2000 on d 12, 13, and 14. Feces were collected from 0800 on d 8 until 0800 on d 12. Chromic oxide was used as the digestibility marker. The AID of GE, CP, and AA and the ATTD of CP and GE were less in the high- than in the low-phytate diet (P < 0.01). With the exception of glutamic acid, phytase supplementation did not affect (P > 0.10) the AID of CP and AA. There was no effect (P > 0.05) of phytase on the ATTD of CP and GE. These results show that if a response occurs to phytase supplementation, it is independent of the dietary phytate content.

6-Phytase↗
PubMed2004

Ileal amino acid digestibility and performance of growing pigs fed wheat-based diets supplemented with xylanase.

Two experiments were conducted to determine the effect of supplementation of xylanase to a wheat-based diet on the apparent ileal digestibility (AID) of AA and the performance of growing pigs fed diets limiting in AA. In Exp. 1, eight pigs (average initial BW = 20.5+/-1.2 kg) fitted with a simple T-cannula at the distal ileum, were fed four diets according to a repeated 4 x 4 Latin square design. Diet 1 was a basal diet that contained 97.6% wheat. Diets 2, 3, and 4 were the basal diet supplemented with xylanase at rates of 5,500, 11,000, and 16,500 units of xylanase activity (XU), respectively (as-fed basis). There were linear and quadratic effects (0.062 < P < 0.001) of xylanase supplementation on the AID of CP and most of the AA. The largest increases in AID of CP and AA were obtained when xylanase was supplemented at a rate of 11,000 XU; no further increases were observed with xylanase supplementation at a rate of 16,500 XU. In Exp. 2, 30 pigs (average initial BW 21.4+/-1.8 kg) were randomly allotted to six dietary treatments. Diets 1 to 4 were similar to those used in Exp. 1. Diet 5 was the same as Diet 1, but supplemented with 0.53% lysine, 0.12% threonine, and 0.05% methionine. Diet 6 (positive control diet) was a wheat-soybean meal diet that contained 18.2% CP (as-fed basis). The total contents of lysine, threonine, and methionine were similar for Diets 5 and 6. There was a linear effect of xylanase supplementation on ADG (P = 0.093) and feed:gain ratio (P = 0.089), and a quadratic effect on ADG (P = 0.067) and feed:gain ratio (P = 0.074). But, the greatest response was obtained with the supplementation of 11,000 XU. The supplementation of lysine, threonine, and methionine to Diet 1 increased (P = 0.001) ADG and ADFI and improved (P = 0.01) feed:gain ratio. There was no difference (P = 0.508) in the performance of pigs fed the AA-supplemented or control diet. In conclusion, the supplementation of xylanase to a diet in which wheat provided the sole source of protein and energy improved the AID of AA, ADG, and feed:gain ratio; however, this improvement was very small compared with that obtained with the supplementation of synthetic amino acids.

Amino Acids↗
PubMed2002

Primary HIV type-1 infection misdiagnosed as Mediterranean spotted fever.

The case studies of four patients, two men and two women between the ages of 42 and 54 years, are described. They presented to a hospital emergency department during the summer months with acute fever and exanthema. These are the primary symptoms of Mediterranean spotted fever (MSF), an endemic rickettsial disease in the Mediterranean basin that is seen particularly during the summer. The patients were clinically diagnosed as having MSF, but their diagnoses were not confirmed by serological testing. One patient was diagnosed with primary human immunodeficiency virus type 1 infection (HIV-1) 10 days later. The remaining three patients were diagnosed with HIV infection years later, but it is very likely that they also had primary HIV infection when MSF was presumed. When a patient develops sudden onset of fever and a maculopapular rash that is characteristic of MSF, the possibility of primary HIV-1 infection should be considered.

Adult↗
PubMed2002

Place-learning, but not cue-learning training, modifies the hippocampal theta rhythm in rats.

Hippocampal theta activity accompanies behaviours such as running, swimming, head movements and spatially orientated responses in the rat. However, whether a relationship between this activity and information processing exists remains unclear. As place-learning depends on hippocampal integrity, whereas cue-learning does not, the hippocampal theta activity underlying each test was evaluated. Local CA1 hippocampal electroencephalograms (EEGs) were recorded over 6 days in a Morris maze for one place-learning test group of rats (n=10) and one cue-learning test group (n=8). The EEG of the corresponding test was taken during waking immobile, searching, and on-platform stages. The relative power (RP) values of EEGs were divided into 4-6.5Hz, 6.5-9.5Hz, and 9.5-12Hz frequency sub-bands. The place-learning training produced a separation of 4-6.5Hz and 6.5-9.5Hz sub-bands in searching and platform stages and a higher activity on the 6.5-9.5Hz sub-band during searching, compared with the basal record, while the cue-learning group did not show differences related either to the training or behavioural stage. As the motor activity and swimming velocity was similar in both groups, the results strongly suggest that the changes observed in theta activity reflect information processing by the hippocampus.

Action Potentials↗
PubMed2002

Reliability of different techniques to assess marginal defects of Class II restorations in retrieved primary molars: a visual-tactile, SEM, dye penetration and polarized light microscopy study.

The aims of the present article were to assess the reliability of different techniques to assess marginal defects in Class II restorations in retrieved primary molars, and to determine the degree of agreement between the various assessment modalities. The material evaluated was comprised of 18 exfoliated primary molars that had been restored 20 to 22 months previously with a resin-modified glass ionomer (Vitremer--7 teeth), a hybridized composite resin (Z100 + Scotchbond Multipurpose--9 teeth), and amalgam (Dispersalloy--2 teeth). No significant differences could be observed between the groups. The majority of the restorations rated A at the buccal and lingual margins, but poor adaptation was disclosed at the cervical margin of the three types of restorations. SEM evaluation revealed that the highest percentage of defects was seen at the cervical margins with no statistically significant difference between the groups. No or minimal leakage was present at the occlusal margins and severe penetration of dye was seen at the cervical margins in all groups. Significantly less demineralization was seen adjacent to the Vitremer and Z100 restorations when compared to the Dispersalloy but no difference was found between the esthetic restorations. Except for the visual tactile examination, small marginal defects could be disclosed by the three assessment techniques (SEM, dye penetration, and polarized light microscopy). A good degree of agreement was observed between the three evaluation techniques.

Child↗
PubMed2001

[Minimally invasive heart surgery].

Minimally invasive heart surgery encompasses a variety of techniques, each with its own objective (minimal incisions, absence of cardiopulmonary bypass and cost reduction). Postoperative care after such procedures are simpler, with early extubation and shortened hospital stays. A period of close observation in a postoperative intensive care recovery ward is still required.

Anesthesia, General↗
PubMed2000

Neoplasia of plasma cells with atypical presentation and infection by the human immunodeficiency virus. A presentation of two cases.

Neoplasia of plasma cells acquires special clinical characteristics in patients infected by human immunodeficiency virus (HIV). These patients are much younger at the time of diagnosis, and when they are compared with the general population they show an atypical clinical evolution, with a greater frequency of solitary plasmacytomas, less evidence of a monoclonal plasmatic component, or greater aggressiveness of the neoplastic process. This paper provides the most significant data on two patients infected by HIV and diagnosed for plasma cell neoplasia. Recent pathogenetic hypotheses for plasma cell neoplasias that include immune alterations, chronic viral infections, and hyperexpression of cytokines exist in patients infected by HIV, and this could suggest that this type of neoplasia is another malignant haematological process associated with AIDS.

Adult↗
PubMed2000

Evidence for a mate-attracting chemosignal in the dwarf African clawed frog Hymenochirus.

Many male frogs and toads possess sexually dimorphic skin glands (breeding glands). However, in most anuran species, the functional significance of the glands is unknown. Here we show that the breeding glands of male dwarf African clawed frogs (Hymenochirus sp. ) release a mate-attractant chemosignal. The mate-attractant activity was assessed using a two-choice aquatic Y-maze. Female Hymenochirus were allowed to choose between different treatment waters (e.g., plain water and water housing males) in the upstream arms of the maze, and the females' movements were monitored by computer-linked motion sensors. Females showed a positive chemotaxis to water housing males and to water containing homogenized breeding glands. Females showed no reaction to water housing conspecific females or to water housing breeding gland-ablated males. Additional choice tests demonstrated that females were more attracted to water housing males than to water housing females and to water containing homogenized breeding glands than to water housing breeding gland-ablated males. Males in the maze showed no response to water housing either females or other males, indicating that the attractant is specific for females and is therefore neither a species aggregation signal nor a food-related attractant. These results represent the first experimental demonstration of a mate-attractant function for anuran breeding glands. Because many anuran species possess breeding glands, these results suggest that pheromonal communication could be more widespread among frogs and toads than previously believed.

Animals↗
PubMed1998

Recurrent hydrochlorothiazide-induced pulmonary edema.

Hydrochlorothiazide-induced pulmonary edema is an unusual but life-threatening adverse reaction. It causes hypoxemia, hypotension, tachycardia, fever, and occasionally electrocardiographic and echocardiographic abnormalities. The mechanism of production is, probably, idiosyncratic.

Aged↗
PubMed1998

Characteristic frequency bands of the cortico-frontal EEG during the sexual interaction of the male rat as a result of factorial analysis.

The electrocorticogram (ECoG) from the prefrontal cortex was simultaneously recorded with the accelerometric signals of pelvic thrusting performed by male rats during sexual behavior. The changes in the prefrontal ECoG were precisely correlated in time with well defined elements of male rat copulation. Principal component analysis allowed to identify three distinct bands of frequencies in the frontal ECoG: the absolute power (AP) of the 4-16 Hz band was increased in the 500-ms periods before, during, and after the execution of pelvic thrusting in mount, intromission and ejaculation responses; the AP of the 18-24 Hz band was selectively increased during the execution of pelvic thrusting at the three copulatory responses, whereas the AP of the 26-32 Hz band was increased only during the pelvic moments of mount and intromission responses. These results show that the electroencephalographic activity of the prefrontal cortex of the male rat is related to the performance of sexual behavior, supporting the concept that this cortical area is involved in the organization of sequential behaviors, as sexual behavior.

Animals↗
PubMed1998

Progesterone: protective effects on the cat hippocampal neuronal damage due to acute global cerebral ischemia.

BACKGROUND: Barbiturates, benzodiazepines, and synthetic steroids having anesthetic properties, by enhancing the inhibitory GABAergic neurotransmission to the neuronal circuits of cerebral structures vulnerable to ischemia, reduce the damage induced by this condition. Some endogenous steroids resulting from progesterone (P4) biotransformation in the brain exert GABAergic effects, thus inhibiting neuronal excitability. Hence, P4 administration both before and after an experimentally induced ischemic episode may prevent or decrease the ischemic cerebral damage. METHODS: Ovariectomized adult cats were treated s.c. with either P4 (10 mg/kg/day) or corn oil during 7 days before and 7 days after being subjected to a period of acute global cerebral ischemia by 15 min of cardiorespiratory arrest followed by 4 min of reanimation. After 14 days of survival, animals were sacrificed and the brains perfused in situ and formalin-fixed for histological examination. RESULTS: Acute global cerebral ischemia resulted in a severe loss of neurons (54-85%), mainly in CA1 and CA2 subfields of oil-treated cats. Progesterone significantly reduced the neuronal loss in those areas (21-49%). CONCLUSIONS: Overall results suggest that progesterone exerts protective effects against the neuronal cerebral damage induced by acute global cerebral ischemia.

Animals↗
PubMed1997

Subcortical multiple unit activity changes during rat male sexual behavior.

Multiple unit activity (MUA) was recorded from the ventral tegmental area (VTA) and mesencephalic locomotor region (MLR) during copulatory behavior of freely moving male rats. Simultaneous accelerometric recordings of the copulatory pelvic thrusting performed by the male rat were taken to precisely correlate in time the changes in MUA with well defined elements of copulation. The baseline MUA firing rates recorded in the quiet-alert condition in the VTA and in the MLR were significantly increased during pursuit of the female by the male; significantly higher MUA firing rates were found in the VTA at the 500 ms periods before and during the execution of pelvic thrusting in mount, intromission, and ejaculation responses as compared to the baseline, and returned to this value when these responses ended. The maximum MUA firing rate in the MLR was obtained during the execution of pelvic thrusting in each copulatory response, and it remained significantly elevated, as compared to the baseline, after thrusting and at the postintromission and postejaculatory genital grooming, then decreasing to basal values at the initial part of the postejaculatory interval. The fact that the highest changes in MUA were related to pelvic thrusting suggests a major participation of both structures in the execution of motor copulatory responses.

Animals↗
PubMed1997

Computer programs to analyze brain electrical activity during copulatory pelvic thrusting in male rats.

Two microcomputer programs have been developed to simultaneously record and analyze the brain electrical activity: multiple unit activity (MUA) and electroencephalogram (EEG), and the accelerometric signals generated in relation to the pelvic thrusting that performs the male rat during the copulatory responses of mount, intromission, and ejaculation. CAPTUMUL is a program allowing the on line capture of the different signals and the further off line delimitation of the brain signals occurring in exact temporal relation with the accelerometric record of motor responses. The ANAMUA program allows the off line analysis of the neuronal firing rate in MUA records at different discrimination levels according to the amplitude of the neuronal spikes, and compare these data in various behavioral situations. The use of these programs provides a way of correlating in time the changes of brain electrical activity occurring in animals in free-movement with the brief motor events of copulation as well as with other behaviors (i.e., genital grooming, sniffing, running, walking). Advantages of this software include the recording of sequential events, a better and rapid handling of data and a reliable method to analyze the MUA with different discrimination levels according to the amplitude of the neuronal spikes.

Animals↗
PubMed1997

Immunological and virological activity of zalcitabine and zidovudine in combination in HIV-positive people with CD4 cell counts of between 200-500 cells/mm3.

We evaluated the effect of combination therapy with zidovudine (AZT) plus zalcitabine (ddC) in human immunodeficiency virus type 1 (HIV-1)-infected patients who had not previously received antiretroviral treatment ('naive' patients). The immunological and virological parameters evaluated were CD4 cell count, syncytium-inducing (SI) viral phenotype and plasma HIV-1 RNA copies/ml (HIV viral load). A total of 75 patients entered the study, with CD4 cell counts between 200 and 500 cells/mm3. All received zidovudine (200 mg) plus zalcitabine (0.75 mg) three times daily for 24 weeks. Treatment was well tolerated. However, four patients presented with anaemia (haemoglobin < 10.0 g/dl) and one patient had both anaemia and neutropenia (0.8 x 10(9) neutrophils/l). Combination therapy with zidovudine plus zalcitabine resulted in a pronounced improvement of virological and immunological markers. Approximately 25% of patients achieved undetectable plasma HIV RNA levels (< 200 copies/ml) at week 24. At the end of the study (24 weeks) a significant reduction (> 0.5 log) of plasma HIV RNA was observed in approximately 70% of patients and in 50% an even greater decrease (> 1 log) was achieved. The most significant decrease in mean plasma HIV RNA levels was observed at week 4, whereas the highest increase in CD4 cell count was found at week 24. Approximately 80% of patients who showed baseline plasma HIV RNA levels below 20000 copies/ml had less than 5000 copies/ml at week 24. The plasma HIV RNA reduction observed at week 4 was significantly maintained at week 24. Therefore, we can rapidly select those who will not respond to therapy and adjust the treatment after a short interval. Our study supports the idea of early therapy because all patients who reached undetectable levels of plasma HIV RNA at week 24 had at baseline a median plasma HIV RNA load of 2560 copies/ml. In conclusion, zidovudine in combination with zalcitabine was well tolerated in the majority of patients and led to a significant reduction in plasma HIV RNA copies in most of the patients with initial viraemia lower than 20000 copies/ml.

Anti-HIV Agents↗
PubMed1996

Serum vitamin A, vitamin E, and beta-carotene levels in preeclamptic women in northern nigeria.

We compared the serum levels of beta-carotene, vitamin A (retinol), and vitamin E (alpha-tocopherol) in healthy pregnant women and their counterparts who exhibited the signs and symptoms of preeclampsia or eclampsia, including: systolic blood pressure greater than 160 mm Hg, edema, and proteinuria. The study was conducted in the cities of Maiduguri and Bauchi, which are located in the semi-arid northeastern region of Nigeria. Most of the pregnant subjects: (1) were teenagers, though they ranged in age from 14 to 25 years; (2) had 2 or fewer prior pregnancies; and (3) were predominantly of the Muslim faith and members of the Hausa, Fulani, or Kanuri ethnic groups. Few of the women had received prenatal care. Serum levels of vitamins A and E and betacarotene were quantified using high pressure liquid chromatography. The serum vitamin A levels of the 9 preeclamptic women (15.3 mg/dL) and the 7 eclamptic women (8.3 mg/dL) were significantly reduced (p < 0.01) relative to the serum vitamin A levels of healthy women in the third trimester (24.2 mg/dL). For the healthy pregnant controls, the levels of vitamins A and E and beta-carotene were relatively constant throughout pregnancy. The mean serum beta-carotene levels for both the preeclamptic and eclamptic groups of subjects were half as high as those of healthy control women in the third trimester (p = 0.004). The serum vitamin E levels of the preeclamptic and eclamptic women were 15% and 30% lower, respectively, than those of the corresponding controls (p < 0.01). The serum levels of these three lipids in the healthy pregnant and non-pregnant women we studied are similar to values reported by others for North American and European women of childbearing age. These results support the hypothesis that preeclampsia-eclampsia deplete natural lipid antioxidants and suggest that the reduced levels of vitamin A in such women experiencing hypertension of pregnancy, if they happen to be infected with the HIV-1 virus, may place them at increased risk for mother-child transmission of the virus.

Adolescent↗