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Biomedical subjects

M Pena

Publications and source records attributed to M Pena.

At least 19 recordsLinked to original sources
PubMed2001

Electrophysiological evidence for automatic phonetic processing in neonates.

At least two fundamental properties should be present in a network computing a phonetic representation: categorical perception and normalization across different utterances. Normalization processes were studied at birth by recording high density evoked potentials to strings of syllables in sleeping neonates. We compared the response to a change of phoneme when irrelevant speaker variation was present or absent. A mismatch response was recorded at the same latency in both cases, suggesting that relevant phonetic information was extracted from the irrelevant variation. Combined with our previous work showing that the mismatch response is sensitive to categorical perception in infants, this result suggests that a phonetic network like that of adults, is already present in the infant brain. Furthermore, efficient phonetic processing does not require attention.

Acoustic Stimulation↗
PubMed2001

Five novel RPGR mutations in families with X-linked retinitis pigmentosa.

X-linked forms of retinitis pigmentosa (XLRP) are among the most severe because of their early onset, often leading to significant visual impairment before the fourth decade. RP3, genetically localized at Xp21.1, accounts for 70% of XLRP in different populations. The RPGR (Retinitis Pigmentosa GTPase Regulator) gene that was isolated from the RP3 region is mutated in 20% of North American families with XLRP. From mutation analysis of 27 independent XLRP families, we have identified five novel RPGR mutations in 5 of the families (160delA, 789 A>T, IVS8+1 G>C, 1147insT and 1366 G>A). One of these mutations was detected in a family from Chile. Hum Mutat 17:151, 2001.

Carrier Proteins↗
PubMed2001

The effect of intranasal fentanyl on the emergence characteristics after sevoflurane anesthesia in children undergoing surgery for bilateral myringotomy tube placement.

UNLABELLED: Children undergoing placement of bilateral myringotomy tubes (BMT) often exhibit pain-related behavior (agitation) in the postanesthesia care unit. We compared the emergence and recovery profiles of pediatric patients who received sevoflurane with or without supplementary intranasal fentanyl for BMT surgery. By using a prospective, double-blinded design, 150 children 6 mo to 5 yr of age, scheduled for routine BMT surgery, were anesthetized with sevoflurane (2%-3%) in a 60% N(2)O/O(2) gas mixture. Patients were randomized to receive equal volumes of intranasal saline (Control), 1 microg/kg fentanyl or 2 microg/kg fentanyl. A blinded observer evaluated each patient using a previously described 4-point agitation scale and the Steward recovery scale. Response to parental presence was observed after a score of six (full recovery) was achieved on the Steward recovery scale. There were no significant differences among the three groups regarding age, weight, surgeon, duration of anesthesia, or ear condition. Recovery times and emergence characteristic scores were not statistically different. Agitation scores were significantly reduced in the 2-microg/kg Fentanyl group as compared with the Control group (P = 0.012). Fentanyl 2 microg/kg is recommended to reduce the incidence of agitation seen in these patients. IMPLICATIONS: We examined the use of nasally administered fentanyl for the relief of agitation or discomfort after placement of bilateral myringotomy tubes in 150 children ages 6 mo to 5 yr using a prospective, double-blinded design. Fentanyl 2 microg/kg was found to reduce the incidence of agitation in these patients.

Administration, Intranasal↗
PubMed1999

Mode of physical activity and self-efficacy in older adults: a latent growth curve analysis.

A randomized controlled trial examined the effect of two physical activity modes on changes in self-efficacy over the course of a 12-month period in older, formerly sedentary adults (N = 174, M age = 65.5 years). Participants were randomized into either an aerobic activity group or a stretching and toning group. Structural equation modeling was employed to conduct multiple sample latent growth curve analyses of individual growth in exercise and physical self-efficacy over time. Results revealed a curvilinear growth pattern for both types of efficacy with increases occurring over the first 6 months followed by declines at the 6-month follow-up. There was a significant treatment by mean level growth interaction for exercise efficacy with both groups increasing over time, but the aerobic group evidenced a twofold increase in growth over the stretching group. Structural analyses indicated that frequency of exercise participation was a significant predictor of overall growth in efficacy, and improvements in fitness were only related to exercise efficacy growth in the stretching group. Findings are discussed in terms of social cognitive theory and further application of latent growth curve modeling to studies of physical activity effects in older adults.

Activities of Daily Living↗
PubMed1997

Blood sample processing effect on eosinophil cationic protein concentration.

BACKGROUND: Asthma is considered to be an inflammatory disease. The most important cell involved in the inflammation is the eosinophil. These cells and their mediators, such as eosinophil cationic protein (ECP), are potential markers of the inflammation's severity. Eosinophil cationic protein may be used for monitoring antiasthma treatment. It is well known that sample processing conditions can affect the ECP blood levels. OBJECTIVE: The aim of this work is to study the effect of temperature, time, and anticoagulants on ECP levels. METHODS: We studied five asthmatic patients and five healthy controls. We obtained three different blood samples from each subject, one with heparin, one with EDTA, and one without anticoagulant. To evaluate the effect of temperature, serum samples were clotted for an hour, one at 0 degree C, one at room temperature, and the other at 37 degrees C. Plasma (heparin and EDTA) samples were treated as follows: one was immediately centrifuged, and two were stored for an hour, one at 0 degree C, and the other at room temperature. Eosinophil cationic protein levels were measured by fluoroimmunoassay (CAP-System ECP FEIA Pharmacia). RESULTS: A higher temperature during blood clotting resulted in a higher ECP concentration. There were no differences between ECP determination in serum samples and plasma samples with heparin, under the same conditions of time and temperature; so clotting may not be necessary for ECP release in vitro. Eosinophil cationic protein was not released in plasma samples with EDTA, neither at 0 degree C nor room temperature. CONCLUSIONS: More studies must be done to clarify the mechanism of the ECP release in vitro.

Adult↗
PubMed1997

[Anorexia nervosa in a patient with type-1 diabetes mellitus].

Female patient, 21 years of age, with diabetes mellitus type I, admitted due to progressive weight loss, with a recent history of impaired glycemic control, ketosis and amenorrhea for 12 months. Studies were conducted in order to exclude an endocrine or malignant disorder. After nutritional, endocrine and psychiatric evaluation, the diagnosis of anorexia nervosa, was made. Therapeutic results and clinical course after the first year are shown. The case raises important problems, especially within diabetic population, puzzling the clues for diagnosis and therapy.

Adult↗
PubMed1992

Mustard allergy. Two anaphylactic reactions to ingestion of mustard sauce.

Two cases of anaphylactic reactions set off by the ingestion of a small amount of mustard sauce are described. Mediation by specific IgE to mustard was determined by skin prick tests and radioimmunoassay, which suggested a type I hypersensitivity mechanism. Despite the antigenic potency of mustard, a spice that is consumed frequently, very few cases of hypersensitivity from ingestion have been described.

Adolescent↗
PubMed1991

Amino acid alterations and encephalopathy in the sepsis syndrome.

OBJECTIVE: To evaluate the role of amino acid profiles in septic encephalopathy. DESIGN: Retrospective analysis. SETTING: Medical wards and medical ICU of a university hospital. PATIENTS: Patients with infections and normal mental status were compared with patients with septic shock and altered sensorium. INTERVENTIONS: Plasma amino acid levels and Acute Physiology and Chronic Health Evaluation (APACHE II) scores were determined. MEASUREMENTS AND MAIN RESULTS: Patients with septic shock and altered sensorium had higher circulating concentrations of ammonia (425 +/- 55 vs. 127 +/- 7 mmol/L) and the aromatic amino acids phenylalanine (122 +/- 19 vs. 74 +/- 3 mmol/L) and tryptophan (97 +/- 7 vs. 32 +/- 13 mmol/L), and lower levels of the branch-chain amino acid isoleucine (48 +/- 7 vs. 68 +/- 5 mmol/L) than patients with infections and normal sensorium (p less than .05). Aromatic amino acid levels correlated with APACHE II scores (R2 = .4, p less than .001) and mortality. APACHE II scores were higher in the septic shock patients (30 +/- 2 vs. 8 +/- 1, p less than .001), and these patients had a higher mortality rate (71% vs. 12%, p less than .01). Patients with septic shock who died had higher levels of ammonia (524 +/- 58 vs. 227 +/- 40 mmol/L, p less than .05) and sulfur-containing amino acids (172 +/- 31 vs. 61 +/- 7 mmol/L, p less than .05) than patients who survived. CONCLUSIONS: Plasma amino acid profiles appear to be important in septic encephalopathy and the severity of septic disease.

Amino Acids↗
PubMed1991

Cancellation in elective orthopaedic surgery.

The management of operating theatre time is a crucial element in the size of surgical waiting lists, and this paper reports a survey of causes of the cancellation of operations for orthopaedic surgery. The results show that, although the majority of cancellations were due to medical causes, others were the result of extended theatre schedules. These findings suggest that closer co-operation between surgical staff, general practitioners and theatre staff could help to reduce this problem.

Appointments and Schedules↗
PubMed1990

Effects of progesterone on postovariectomy bone loss in aged rats.

The effects of progesterone on oophorectomy-induced bone loss in aged rats were evaluated. Female rats aged 12 months were divided into three groups: (1) sham-operated controls (SHAM); (2) oophorectomized (OVX); (3) OVX rats treated with progesterone (OVX + PROG). After 20 weeks the dry weight, bone ash, and calcium content of femur, tibia, and fourth lumbar vertebra were significantly lower in OVX than in sham rats. These reductions did not occur in OVX rats treated with PROG. There was no difference in the bone composition between the control and progesterone-treated rats. Vertebral bone histomorphometry showed increased bone resorption as well as increased bone formation parameters in OVX rats. Progesterone treatment inhibited the increased resorption indices, but the bone formation remained elevated. The results indicate that progesterone therapy prevents the postovariectomy bone loss in aged rats. The protective effect of progesterone is mediated by inhibition of bone resorption while maintaining the increased bone formation. These findings suggest that progesterone alone may be a valuable agent for management of postmenopausal osteoporosis.

Aging↗
PubMed1990

Etodolac: analgesic effects in musculoskeletal and postoperative pain.

Numerous clinical trials have shown etodolac to be an effective analgesic. The purpose of the present report is to review results of 14 studies that demonstrate the effectiveness of etodolac in a variety of painful conditions. Presented are the results of four postsurgical pain studies, one study of acute gouty arthritis and nine studies of acute musculoskeletal disorders: acute low back pain, acute painful shoulder, tendinitis and bursitis, and acute sports injuries. A single oral dose of etodolac (25, 50, 100, 200, or 400 mg) was compared with aspirin (650 mg) or a combination of acetaminophen (600 mg) plus codeine (60 mg) for the relief of pain up to 12 h following oral, urogenital or orthopedic surgery. In multiple dose studies of acute gouty arthritis and musculoskeletal conditions, etodolac 200 or 300 mg twice a day (b.i.d.) or 200 mg three times a day (t.i.d.) was compared with naproxen 500 mg b.i.d. or t.i.d., diclofenac 50 mg b.i.d. or t.i.d., and piroxicam 20 or 40 mg once a day (o.d.) administered over 5 to 14 days. The efficacy of etodolac was at least equal and in some ways superior to aspirin and acetaminophen plus codeine in the relief of postsurgical pain. In studies of acute gouty arthritis, significant improvement from baseline were seen for all efficacy parameters evaluated for both the etodolac- and naproxen-treated patients. All the present studies of musculoskeletal conditions have shown etodolac to be effective and comparable in analgesic efficacy to naproxen, diclofenac or piroxicam. In summary, etodolac therapy for pain following surgery, in acute gouty arthritis and in acute musculoskeletal conditions resulted in analgesia comparable to that provided by several well-established analgesic or anti-inflammatory agents.

Acetaminophen↗
PubMed1990

Clinical antecedents to in-hospital cardiopulmonary arrest.

While the outcome of in-hospital cardiopulmonary arrest has been studied extensively, the clinical antecedents of arrest are less well defined. We studied a group of consecutive general hospital ward patients developing cardiopulmonary arrest. Prospectively determined definitions of underlying pathophysiology, severity of underlying disease, patient complaints, and clinical observations were used to determine common clinical features. Sixty-four patients arrested 161 +/- 26 hours following hospital admission. Pathophysiologic alterations preceding arrest were classified as respiratory in 24 patients (38 percent), metabolic in 7 (11 percent), cardiac in 6 (9 percent), neurologic in 4 (6 percent), multiple in 17 (27 percent), and unclassified in 6 (9 percent). Patients with multiple disturbances had mainly respiratory (39 percent) and metabolic (44 percent) disorders. Fifty-four patients (84 percent) had documented observations of clinical deterioration or new complaints within eight hours of arrest. Seventy percent of all patients had either deterioration of respiratory or mental function observed during this time. Routine laboratory tests obtained before arrest showed no consistent abnormalities, but vital signs showed a mean respiratory rate of 29 +/- 1 breaths per minute. The prognoses of patients' underlying diseases were classified as ultimately fatal in 26 (41 percent), nonfatal in 23 (36 percent), and rapidly fatal in 15 (23 percent). Five patients (8 percent) survived to hospital discharge. Patients developing arrest on the general hospital ward services have predominantly respiratory and metabolic derangements immediately preceding their arrests. Their underlying diseases are generally not rapidly fatal. Arrest is frequently preceded by a clinical deterioration involving either respiratory or mental function. These features and the high mortality associated with arrest suggest that efforts to predict and prevent arrest might prove beneficial.

Female↗
PubMed1990

Normocaloric diet and exercise: a good choice for treating obese adolescents.

The results of a slimming treatment in which the main features were: energy intake according to expected body weight for height (normocaloric), exercise, education and psychological support, are evaluated after one year of experience. Twenty-four obese adolescents (15 boys and 9 girls), out of thirty who started treatment, completed this stage successfully. Pubertal changes occurred and growth continued normally, mainly of lean body mass, as shown by the increase of lean body weight and muscle area of the mid-upper arm. A substantial loss of fat, expressed in a reduction of fat weight, relative fatness and fat areas of the mid-upper arm was obtained. Body weight for height shifted to lower percentile channels. The results are promising in indicating the successful treatment of obese subjects in a period of rapid growth without affecting their normal development, profiting also from the usually-observed decrease in fatness at this age. In view of the success in motivating most of the subjects to maintain the continuity of diet and physical activity, this method is considered a good choice for treating obese adolescents without severe energy restriction, thus assuring lasting effects instead of the short-term ones commonly reported in the literature.

Body Composition↗