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Biomedical subjects

M E Cruz

Publications and source records attributed to M E Cruz.

At least 37 records · Page 2Linked to original sources
PubMed1995

EEG abnormalities, malnutrition, parasitism and goitre: a study of schoolchildren in Ecuador.

We report on data collected in a sample of 194 schoolchildren (9-13 years of age) residing in a mountainous community in Ecuador. This study was part of an ongoing epidemiological inquiry into the prevalence of parasitism, malnutrition, neurocysticercosis, goitre, iodine levels and EEG abnormalities, and the relationships among these factors. Data were obtained by a local medical team supported by specialized personnel. The results showed that 34% of the EEG tracings were abnormal, with higher rates among girls. The best fitted log-linear model to explain the results was the combination of EEG status, parasite infection, goitre and gender. The best predictor of EEG abnormalities was found to be a diagnosis of goitre.

Adolescent↗
PubMed1995

Prevalence of neurological disorders in Haute-Vienne department (Limousin region-France).

The Limousin region had at present one of the largest elderly populations in France and in Europe. To determine the frequency of certain neurological disorders in the elderly, a neuroepidemiological survey was conducted in 1986-1987 on a representative sample of the population in Haute-Vienne (the most population-dense department in the Limousin region). This study used a WHO protocol which was first introduced at the beginning of the 1980s. It had been previously tested in France on a pilot population in 1984. The prevalences of the principal neurological disorders encountered per 100,000 inhabitants were as follows: nonmigraine headache 5,059, migraine 4,270, epilepsy 788, completed stroke 1,445, transient ischemic attacks 657, neuropathy 1,642, Parkinson's disease 328, and dementia 197.

Adolescent↗
PubMed1995

Neurocysticercosis and performance on neuropsychologic tests: a family study in Ecuador.

Neurocysticercosis (NCC) is a common neurologic disorder in developing countries, where it may pose a major public health challenge. Recently, the disorder has become more commonly diagnosed in developed countries as a result of the influx of migrants from countries where the disease is endemic. The clinical syndrome associated with NCC includes neurologic, physical, and functional problems. Since the locus of the infection is mainly the central nervous system, there is a risk of neuropsychologic dysfunction. This study was conducted in Ecuador in a group of 123 subjects (49 males and 74 females, 9-62 years of age) from a community sample that was part of a larger neuroepidemiologic inquiry. A discriminant function procedure was used to select the tests that would be most sensitive at distinguishing between affected and nonaffected individuals. The results suggest that behavioral functions that include aspects of inhibitory control, motor, and visual-motor output are impaired in adolescent and adult subjects with NCC.

Adolescent↗
PubMed1994

Asymmetrical changes in the choline acetyltransferase activity in the preoptic-anterior hypothalamic area during the oestrous cycle of the rat.

There is evidence that the cholinergic system modulates, in a circadian and asymmetric way, the neural activity involved in the regulation of ovulation. In the present study we measured choline acetyltransferase (ChAT) activity during the oestrous cycle in both sides of the preoptic-anterior hypothalamic area (POA-AHA) of the rat. The right side of POA-AHA showed significant changes in ChAT activity during the oestrous cycle. The activity of the enzyme was higher in the right side on the day of oestrous (47.3 +/- 3.2 nmol mg-1 protein 1 h-1 vs 25.8 +/- 2.4, p < 0.05), whilst on the second day of dioestrous the activity was higher in the left one (30.6 +/- 3.4 vs 20.0 +/- 1.5). The differences in the activity of ChAT observed support the idea of the existence of asymmetry in the POA-AHA cholinergic system which varies during the oestrous cycle.

Animals↗
PubMed1994

Liposomal palmitoyl-L-asparaginase: characterization and biological activity.

A new derivative of L-asparaginase, palmitoyl-L-asparaginase (palmitoyl-L-ASNase), has been incorporated in liposomes. For this purpose we modified the dehydration-rehydration method and optimized the liposomal composition. The pharmacokinetics, toxicity, and in vivo antitumor activity against P1534 lymphoma of different liposomal palmitoyl-L-ASNase formulations were studied. Liposomal encapsulation of palmitoyl-L-ASNase as compared with free palmitoyl-L-ASNase resulted in a prolongation of the blood half-life (from 2.88 h to longer than 23.7 h), abrogation of acute toxicity, and preservation of in vivo antitumor activity.

Animals↗
PubMed1994

Differences in the ovulatory response to unilateral lesions in the preoptic or anterior hypothalamic area performed on each day of the estrous cycle of adult rats.

The effects of a unilateral lesion made on the right or left side of the preoptic area (POA) or anterior hypothalamic area (AHA) made on each day of the estrous cycle, were analyzed. Ovulation rate decreased among the animals with a lesion performed on the day of estrous on the right side of POA (1/7 vs. 7/7, p < 0.05) and in animals with a lesion on diestrus-1 on each side AHA (4/9, 4/9 vs. 7/7, p < 0.05). Ovulation was restored by GnRH injection, while estradiol benzoate administration restored ovulation only in rats with a lesion on the right side of POA or AHA. We suggest that the participation of POA and AHA in the regulation of ovulation is asymmetric, lateralized, and changes during the estrous cycle. The estrogen-positive feedback needs the integrity of the left side of AHA on diestrus-1.

Animals↗
PubMed1994

Efficacy of 28-day and 40-day regimens of sodium stibogluconate (Pentostam) in the treatment of mucosal leishmaniasis.

The efficacy and toxicity of two regimens of antimony, 28 and 40 days of 20 mg of antimony/kg/day, were compared in the treatment of culture-positive mucosal leishmaniasis involving more than one anatomic site. Forty consecutive eligible Peruvians with infiltrative or ulcerative mucosal disease of the lips, nose, palate-uvula-pharynx, or larynx-epiglottis were randomized to receive either 28 days (P28) or 40 days (P40) of sodium stibogluconate (Pentostam). Treatment was prematurely terminated due to thrombocytopenia in three patients and two patients did not complete six months of follow-up. At one month post-treatment, 13% (2 of 16) of the P28 patients and 16% (3 of 19) of the P40 patients no longer had infiltrates or ulcers and were initially considered cured. During a further 11 months of follow-up, infiltrated lesions healed in eight more P28 patients and in 10 more P40 patients. The cure rate after 12 months of follow-up was therefore 63% for both groups (10 of 16 in the P28 group and 12 of 19 in the P40 group). The total of 13 patients who had infiltrates or ulcers at the 9-12-month follow-up were considered failures. All seven patients (three in the P28 group and four in the P40 group) whose lesions were culture-positive for Leishmania at some point in the 12 months after treatment, and who were thereby parasitologic failures, were also clinical failures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Human subcutaneous Taenia solium cysticercosis in an Andean population with neurocysticercosis.

Subcutaneous involvement by the larval stages of the pork tapeworm Taenia solium in patients suffering from neurocysticercosis (neurocysticercosis) is well-described. It has been a clinical but undocumented impression that subcutaneous nodules are less common in cases of neurocysticercosis in Latin American than in Africa or Asia. We report on the absence of subcutaneous nodules found in a screened population of 2,891 residents of an Andean village in Ecuador with a prevalence rate for neurocysticercosis of 144 per thousand. Thirty-four patients with multiple intracranial calcifications and or cystic or encephalitic parenchymal lesions of neurocysticercosis were examined and questioned about subcutaneous nodules. Only one patient described nodules and this computed tomography plain films are presented. Several hypotheses are presented as to why nodules may be less common in this Andean community with a high prevalence of neurocysticercosis.

Adolescent↗
PubMed1992

A comparative analysis of the neuroendocrine mechanisms regulating ovulation, affected by a unilateral implant of atropine in the preoptic-anterior hypothalamic area, in intact and hemiovariectomized adult rats.

The effects were analysed of a unilateral implant of atropine on ovulation in intact and hemiovariectomized adult rats, together with the response of the atropine-implanted rats to hormone replacement. An outer cannula directed to the left or right preoptic (POA)-anterior-hypothalamic area (AHA) was implanted into cyclic adult rats. A group of animals in oestrus was hemiovariectomized and some were also implanted with a cannula. After two consecutive 4-day cycles, the hemiovariectomized animals were implanted with atropine (23 +/- 4 micrograms) or cholesterol (25 +/- 2 micrograms) on the day of oestrus. Atropine implanted into the left side of the POA-AHA blocked ovulation and compensatory ovarian hypertrophy, whilst implants in the right side had no effects. Administration of gonadotrophin-releasing hormone (GnRH; 3.7 micrograms/kg) at 13.00 h on the expected day of pro-oestrus induced ovulation in six out of seven treated animals. Of 19 rats with an implant of atropine in the left side of the POA-AHA, one ovulated after treatment with pregnant mare serum gonadotrophin (PMSG) on oestrus, or oestradiol benzoate or human chorionic gonadotrophin (hCG) on day 2 of dioestrus. The effects on ovulation of a unilateral implant of atropine into the POA-AHA of cyclic adult rats and the responses of such rats to GnRH, PMSG, hCG and oestradiol benzoate replacement were also studied. Ovulation was induced in rats with a unilateral implant of atropine and which had been treated with GnRH or hCG at 13.00 h on the expected day of pro-oestrus after the implant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Efficacy and toxicity of sodium stibogluconate for mucosal leishmaniasis.

OBJECTIVE: To determine the efficacy and toxicity of the World Health Organization's (WHO) recommended treatment for mucosal leishmaniasis: antimony, 20 mg/kg body weight per day for 28 days. DESIGN: Open trial with 12-month follow-up. SETTING: Inpatient unit of a regional referral hospital in a developing country. PATIENTS: Twenty-nine consecutive eligible patients with culture-confirmed infection of the mucosa with Leishmania species who were otherwise healthy. Eight patients (28%) had mild to moderate disease (confined to the nasal mucosa). Twenty-one patients (72%) had severe disease (including the oropharynx as well as the nasal mucosa). INTERVENTION: Antimony, 20 mg/kg body weight intravenously every day for 28 days. Patients received antimony in the form of sodium stibogluconate. MEASUREMENTS AND MAIN RESULTS: Initial results of therapy were as follows: 63 of 72 lesions (88%) healed or markedly improved; all lesions were culture-negative for parasites; and 18 of 29 patients (62%) showed complete clinical and parasitologic cure of all lesions. By the 12-month follow-up examinations, however, 37 lesions had recurred, 8 new lesions had appeared, and only 8 patients (30%) showed clinical cure of all lesions. Of the 8 patients with mild to moderate disease, 6 were cured compared with only 2 of the 21 patients with severe disease. Side effects of this treatment regimen included T-wave inversion on electrocardiogram (4 patients), abnormal liver function tests (10 patients), and musculoskeletal pain (24 patients). No side effects occurred during week 1 of therapy. CONCLUSIONS: The only recommended treatment for mucosal leishmaniasis is ineffective in patients with severe disease. The acceptable toxicity of the regimen suggests that longer courses of therapy with antimony, or that trials with other antileishmanial agents alone or combined with antimony be evaluated as initial therapy for this disease.

Adult↗
PubMed1990

Clinical pattern and the genetics of the fetal iodine deficiency disorder (endemic cretinism): results of a field study in Highland Ecuador.

The clinical manifestations of various degrees of mental retardation, spastic diplegia, and deaf mutism are known as the neurologic type of endemic cretinism (EC), occurring in countries with high goiter endemicity. Maternal iodine deficiency has been established as the major cause in EC, whereas a genetic predisposition has not been well-documented. Genetic data on 70 families with EC from Highland Ecuador are reported. A segregation analysis of 49 fully classified families yielded an estimate of P = 0.245 (var [P] = 0.00167). Half-sibs were all unaffected and no significant birth order effect was observed among 101 probands. The data indicate an autosomal recessive predisposition as a major etiological factor. Because the neurologic type of EC represents a defined section of the spectrum of iodine deficiency disorders (IDD), the term fetal iodine deficiency disorder (FIDD) rather than cretinism is suggested. The clinical findings in 70 patients were used to delineate the minimal diagnostic criteria of FIDD.

Abnormalities, Multiple↗
PubMed1990

Acylation of L-asparaginase with total retention of enzymatic activity.

Acylation of L-asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) with complete retention of catalytic activity was achieved. Several parameters of the acylation method, based on the binding of palmitoyl residues to epsilon-NH2 groups of protein, were optimized. The correlation between the acylation degree of L-asparaginase and the retention of catalytic activity was established. For a palmitoyl chloride/protein molar ratio ranging from 50 to 900, a degree of modification of 10 to 30% and a retention of catalytic activity of 98 to 60% respectively, was observed. Hydrophobicity of 30% acylated protein was correlated with turbidity in water and octanol and was compared with the native protein. Acylated protein incorporated into liposomes, showed an increase in catalytic activity in intact form as compared to the native enzyme. By the introduction of a sequential acylation cycle, an improvement of the degree of modification with a maximal value at 50% was obtained. Total retention of catalytic activity was achieved by acylation in the presence of 8 mM L-asparagine in a reactional medium.

Acylation↗
PubMed1990

Differences in spontaneous ovulation in rats with unilateral lesion of the hypothalamus.

The effects of unilateral lesion of the anterior (AH), median (MH) or posterior hypothalamus (PH) performed on diestrus 1, on ovulation and estrous cycle were analyzed in virgin rats. Only rats showing two consecutive estrous cycles of the same length were used. The lesion of AH decreased the ovulation rate (number of ovulating/number of treated rats) (14/26 vs. 24/24 of sham-operated group, p less than 0.01, Chi-square test), and the number of released ova per rat (5.0 +/- 1.1 vs. 10.3 +/- 0.8, p less than 0.05). Meanwhile, for ovulating animals no differences in the number of ova shed were observed. Lesions of the MH or PH did not modify the ovulation rate nor the number of ova shed. The left ovary of rats with MH and PH lesions, however, shed less ova than the left ovary of the control group (MH: 4.1 +/- 0.5; PH: 3.9 +/- 0.6; control: 5.7 +/- 0.5, p less than 0.05). These results suggest that neural information arising from the AH, MH or PH plays different roles in the regulation of ovulation.

Animals↗
PubMed1990

Differential effects of a unilateral hypothalamic lesion on ovulation and compensatory ovarian hypertrophy in hemiovariectomized adult rats.

The effects were analysed of a unilateral lesion in the anterior or medial hypothalamus made on the day of oestrus on right or left hemicastrated rats. On the day of oestrus after two consecutive oestrous cycles of the same length, the ovulation rate in rats with lesions in the anterior left hypothalamus was lower than in control hemicastrated animals (5/16 vs 18/20; P less than 0.01), and normal in those rats with lesions in the right side (14/18). None of the animals with lesions in the left side of the anterior hypothalamus and with the left ovary in situ ovulated (0/7), but 5/9 with the right ovary in situ did ovulate (P less than 0.05). Lesions on either side of the medial hypothalamus did not modify ovulation rate. Compensatory ovulation was reduced in those animals with lesions in the right anterior hypothalamus and with the right ovary in situ. Lesions in either side of the medial hypothalamus reduced compensatory ovulation. Lesions in the right side of the anterior and medial hypothalamus increased compensatory ovarian hypertrophy in the left ovary and decreased it in the right ovary. Lesions in the left side of the anterior hypothalamus increased compensatory ovarian hypertrophy in the left ovary only, whereas lesions in the left side of the medial hypothalamus reduced compensatory ovarian hypertrophy in the right ovary. The results suggest that the information arising in each side of the anterior and medial hypothalamus plays different roles in the ipsi-and contralateral ovary, when either the left or the right ovary is absent.

Animals↗
PubMed1989

Asymmetric ovulatory response induced by a unilateral implant of atropine in the anterior hypothalamus of the cyclic rat.

The effects were analysed, on ovulation at the next oestrus, of unilaterally implanting atropine in the anterior hypothalamus of rats on each day of the oestrous cycle. Implantation on day 1 of dioestrus on either side of the anterior hypothalamus blocked ovulation. Implantation on the left side of the hypothalamus on day 2 of dioestrus blocked ovulation in all animals, whereas implantation on the right side allowed 71% of the animals to ovulate (0/4 vs 5/7; P less than 0.05). Implantation at pro-oestrus on either side of the hypothalamus did not modify the rate of ovulation. When implantation was carried out on the day of oestrus on the right, none of the animals ovulated, but all ovulated when the implant was on the left (0/8 vs 8/8; P less than 0.01). The results suggest the existence of a cholinergic hypothalamic lateralization in the mechanism regulating ovulation which depends on the day of the oestrous cycle.

Animals↗
PubMed1987

Differences in the ovulation rate of the right or left ovary in unilaterally ovariectomized rats: effect of ipsi- and contralateral vagus nerves on the remaining ovary.

The possible existence of peripheral asymmetry in the neuroendocrine mechanisms participating in the response of the ovary to gonadotrophins, and the participation of the vagus nerve, was investigated. At oestrus, the ovulation rate (number of ovulating/number of treated rats) of the left ovary in right unilaterally ovariectomized rats was lower than that in the right ovary in left unilaterally ovariectomized rats (42 vs 84%). No differences in the number of ova shed per ovulating animal nor in compensatory ovarian hypertrophy (COH) were observed. Bilateral section of the vagus nerve resulted in reduced COH only in those animals with the left ovary in situ (right unilaterally ovariectomized). Section of the left vagus nerve induced different effects depending upon which ovary was left in situ. When the left ovary was in situ an increase in ovulation rate, COH and number of ova shed was observed; however, when the right ovary was left in place the above three parameters decreased. Section of the right vagus nerve produced a decrease only in COH in both right and left unilaterally ovariectomized animals. It is concluded that in the unilaterally ovariectomized rat the right ovary seems more able to react to compensatory regulatory systems than does the left. The character of the information carried by the left and right vagus nerve is different.

Animals↗