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Biomedical subjects

J A Costa

Publications and source records attributed to J A Costa.

At least 19 recordsLinked to original sources
PubMed2001

Action of selective serotonin reuptake inhibitor on aggressive behavior in adult rat submitted to the neonatal malnutrition.

The effect of the malnutrition during suckling on the aggressiveness was investigated in adult rats treated or not with citalopram, a selective serotonin reuptake inhibitor (SSRI). The animals were divided into two groups according to the diet used: nourished group - the rats received the control diet with 23% protein during the life; and malnourished group - the rats had its mothers submitted to diet with 7.8% protein during suckling. At 120 days of age, each group was sub-divided according to the treatment: acute - consisting a single i.p. injection of saline solution or 20-mg/Kg citalopram; chronic - consisting the single injections (1 per day during 14 days) of saline or 20 mg/Kg citalopram. The acute or chronic treatment with SSRI reduces aggressive response in nourished rats, but not in malnourished ones. Thus, the malnutrition during the critical period of brain development seems to induce durable alterations in the function of the serotoninergic neurotransmission

Aggression↗
PubMed2001

Reduction of intraspecific aggression in adult rats by neonatal treatment with a selective serotonin reuptake inhibitor.

Most studies suggest that serotonin exerts an inhibitory control on the aggression process. According to experimental evidence, this amine also influences growth and development of the nervous tissue including serotoninergic neurons. Thus, the possibility exists that increased serotonin availability in young animals facilitates a long-lasting effect on aggressive responses. The present study aimed to investigate the aggressive behavior of adult rats (90-120 days) treated from the 1st to the 19th postnatal day with citalopram (CIT), a selective serotonin reuptake inhibitor (20 mg/kg, s.c., every 3 days). Aggressive behavior was induced by placing a pair of rats (matched by weight) in a box (20 x 20 x 20 cm), and submitting them to a 20-min session of electric footshocks (five 1.6-mA - 2-s current pulses, separated by a 4-min intershock interval). When compared to the control group (rats treated for the same period with equivalent volumes of saline solution), the CIT group presented a 41.4% reduction in the duration of aggressive response. The results indicate that the repeated administration of CIT early in life reduces the aggressive behavior in adulthood and suggest that the increased brain serotoninergic activity could play a role in this effect.

Aggression↗
PubMed2000

Methylene blue inhibits polymerase 1 enzyme and sensitizes Escherichia coli bacteria to X-rays.

PURPOSE: To investigate the mechanism of methylene blue-induced radiosensitization in Escherichia coli cells. MATERIALS AND METHODS: Bacteriophage lambda15 was irradiated with X-rays in the presence or absence of methylene blue (MB) and infected into bacteria with different repair capabilities preincubated with or without MB. The survival of the bacteriophage in each bacterial strain was used to quantify MB-induced radiosensitization. DNA repair in bacteria irradiated with X-rays and incubated with or without MB was examined by alkaline and neutral sucrose gradients. An in vitro repair system of pBR322 plasmid DNA irradiated with X-rays was designed to determine the repair enzyme targeted by MB. CONCLUSIONS: MB impairs the repair activity of the polymerase 1 enzyme in E. coli cells, sensitizing these bacteria to the lethal effects of ionizing radiation. Since MB accumulates preferentially in some malignant tumours, it will be of interest to investigate its effects on the repair of irradiated human cells.

Centrifugation, Density Gradient↗
PubMed2000

Spinal cord neuromodulation for voiding dysfunction.

A clear understanding of the pathophysiology and neurophysiologic effect of neuromodulation is lacking. Apparently there is a balance of efferent and afferent negative and positive feedback loops that are augmented by external electrical stimulation. This effect may be dramatic even in patients who have have not benefited from virtually every other form of treatment.

Electric Stimulation Therapy↗
PubMed1999

Estimating the number of clusters in multivariate data by self-organizing maps.

Determining the structure of data without prior knowledge of the number of clusters or any information about their composition is a problem of interest in many fields, such as image analysis, astrophysics, biology, etc. Partitioning a set of n patterns in a p-dimensional feature space must be done such that those in a given cluster are more similar to each other than the rest. As there are approximately Kn/K! possible ways of partitioning the patterns among K clusters, finding the best solution is very hard when n is large. The search space is increased when we have no a priori number of partitions. Although the self-organizing feature map (SOM) can be used to visualize clusters, the automation of knowledge discovery by SOM is a difficult task. This paper proposes region-based image processing methods to post-processing the U-matrix obtained after the unsupervised learning performed by SOM. Mathematical morphology is applied to identify regions of neurons that are similar. The number of regions and their labels are automatically found and they are related to the number of clusters in a multivariate data set. New data can be classified by labeling it according to the best match neuron. Simulations using data sets drawn from finite mixtures of p-variate normal densities are presented as well as related advantages and drawbacks of the method.

Algorithms↗
PubMed1995

Pregnancy and kidney transplantation: experience in a developing country.

Between January 1968 and December 1992, 136 kidney transplants were performed in the University Hospital of Ribeirão Preto, with women of childbearing age (14 to 40 years) as receptors. From this population, 19 patients became pregnant at least once after transplantation, and 2 were transplanted inadvertently during the first trimester of their pregnancies. There was a total of 25 pregnancies and 27 offspring. The mean age at the time of conception was 28.6 years (23 to 41 years), with a mean interval of 3.5 years from transplant to conception (< 1 to 16 years). All patients continued their immunosuppressive regimens during the entire pregnancy, but only 5 of 25 were taking cyclosporine. There were two miscarriages (8%) and two therapeutic abortions (8%); of those that passed the 20th week of pregnancy, the mean gestation time at delivery was 35 weeks (range, 28 to 38 weeks) with an incidence of prematurity (gestation < 37 weeks) of 67%, and their offspring weighed from 670 to 3,100 g (mean, 2,236 g), presenting a very high incidence of low birthweight (64%). There was one stillborn and one neonatal death. The most common complications that occurred during pregnancy were infections (especially urinary tract and vaginal mycotic infections) followed by hypertension. The obstetric complications were distributed as follows: premature rupture of membranes in 27%, fetal distress in 24%, preterm labor in 24%, and oligohydramnios in 10%. Lower segment cesarean section was necessary in 16 of 21 cases (76%), and all were for obstetric reasons. One patient died during the puerperium because of sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Neonatal treatment with naloxone causes permanent hyperalgesia in rats.

The effect of treatment with naloxone early in life on pain responsiveness was studied in Wistar rats. Litters of six rats were divided equally into groups of 3 pups receiving daily naloxone (50 mg/kg, sc) and 3 pups receiving saline from the 3rd to 18th day of life. On days 30, 50, 70 and 90, one group of animals previously injected during suckling with naloxone (N = 21) and another with saline (N = 21) were submitted to the hot-plate test to measure the latency to paw licking. Other groups of rats also treated during suckling with naloxone (N = 13) and saline (N = 14) were assessed for the antinociceptive effect of morphine (10 mg/kg,sc). The naloxone group displayed a lower latency than the saline group in all test sessions and a diminished analgesic response to morphine. The results indicate that the use of naloxone (an antagonist opioid) during suckling, the brain growth spurt period, facilitates a long-lasting increased pain responsiveness and alters antialgesic mechanisms. In this respect, the opioid and non-opioid effects of naloxone on the ontogeny of neural systems should be taken into account.

Animals↗
PubMed1987

Sciatic nerve conduction velocity of malnourished rats fed the human "basic regional diet" of the northeast of Brazil.

1. Rats were fed the "basic regional diet" (BRD) utilized by some human populations in northeastern Brazil, which contains only 7.8% protein (mainly from beans), to produce a form of malnutrition. The effects of chronic malnutrition on nerve impulse conduction velocity was studied in the sciatic nerve of young (121-143 days) and old (420-540 days) rats. 2. BRD rats presented a 50% reduction in sciatic nerve conduction velocity compared to controls fed a diet containing 22% casein. 3. Rats chronically fed a commercially available diet (CD group) containing an intermediate level of protein (14%) presented conduction velocities intermediate between values obtained from control and BRD rats (62% to 76% of the control values). 4. The conduction velocities of animals belonging to the same nutritional group were independent of sex, body weight or age. 5. Nutritional restriction imposed only in adult life by increasing the number of rats per cage in the casein group did not have any effect on the conduction velocity of nerve impulses. 6. The severity of the effects observed in the malnourished rats may be related to the quantity and quality of protein in the diet. In this respect, the present data agree with those reported in the literature on human and animal experiments. 7. The present results justify the use of the foods ingested by malnourished human populations for the development of experimental animal models of malnutrition.

Age Factors↗
PubMed1984

[Basal cell epithelioma of the vulva in chronic endemic regional arsenic poisoning].

A 65 years old patient with vulvar basal cell carcinoma and cutaneous manifestations of chronic arsenicism is reported; by its endemic origin is considered as hidroarsenicism ( ERCHA = endemic regional chronic hidroarsenicism ). The unusual presentation of this type of cancer is resalted , and it's attributed to its general disease . The principal characteristics of arsenical skin cancer are considered.

Aged↗
PubMed1984

[Liver ultrastructure in congenital atresia of the extrahepatic bile ducts].

Seven patients with diagnosis of biliary atresia (BA) and two patients with neonatal hepatitis were studied by electron microscopy. In all patients the diagnosis was done by clinical examinations, laboratory assays, histological studies by punch or surgical biopsies and or surgical examinations combined with intraoperatory cholangiography. The ultrastructural alterations found in both groups of patients were essentially similar to those described in other forms of cholestasis. In patients suffering from biliary atresia the main features found at hepatocytic livel were: Finely granular deposits of electron dense substance sometimes conforming lamellar structures; 2) Some increase and vesiculation of smooth endoplasmic reticulum membranes; 3) Reductions in number and length of sinusoidal microvilli; in some areas was also detected basal membrane and an increase in the amount of collagen fibers in the space of Disse; 4) Marked bile canaliculi dilatations with reduction of microvilli and thickening of the pericanalicular surrounding area, some canaliculi were constitued by several hepatocytes. Ductules were found in only 3 cases with the following alterations: 1) Intracytoplasmic electron dense deposits of granular material without limiting membranes; 2) A marked increase in the number of microfilaments mainly located in the apical portion of the cell or in the vicinity of the nuclei; 3) Inflammatory cells in the duct epithelium or in direct contact with the hepatocytes. The ultrastructural findings in the two cases of neonatal hepatitis (NH) resembled those described in the biliary atresia.(ABSTRACT TRUNCATED AT 250 WORDS)

Bile Ducts↗
PubMed1983

[Subcutaneous fat necrosis of the newborn infant. Apropos of 2 cases].

Two cases of subcutaneous fat necrosis of the newborn are reported, an infrequent disease characterized by nodules or cutaneous endurated plaques that appears a few days after birth, which histopathologic studies shows fat necrosis with formation of giant cells granulomas strange body type and the presence of needle shaped clefts corresponding to fat crystals. This is a benign disease that has to be to differentiated from sclerema neonatorum, a serious entity which coexists with another disease so we also think it could be more a symptom than an authentic thickness. The two entities are vinculated physiopathologically by the injury of the fat tissue with a minor quantity of oleic acid and a major relative proportion of palmitic and stearic acid; than that of the adult, which conditions its easy solidification.

Fat Necrosis↗
PubMed1983

[Angiokeratomas. Apropos of 8 cases].

Eight patients with angiokeratomas are reported; three of them with angiokeratoma circumscriptum present at birth, three angiokeratoma Fordyce type with vulvar location, another one with scrotum location all these appeared by the third decade and the other one a solitary angiokeratoma which age of onset was forty-one years. The clinical and histopathological aspects of the angiokeratoma are studied.

Adult↗
PubMed1983

[Autoimmunity factor in chronic gastritis: incidence of antiparietal cell antibodies and their relation to antral histology and basal blood gastrins].

In 118 patients with histological proven chronic gastritis, was performed a study of seric antibodies against parietal cells (ACCP), following the indirect inmuno-fluorescence method. The results were positives in 36 cases (30%). Four positives cases were found in 40 normal controls (10%), two of them were compensated diabetics, one have the thyrohyoid Hashimoto's disease, and the remainder, brother of a patient with chronic gastritis, was a positive ACCP. A major positiveness (44.4%) was obtained in 9 cases of gastric atrophy than in 65 cases with atrophic gastritis (32%) and in 44 cases of superficial gastritis (25%); although due to the few cases of gastric atrophy regarding other histological types, conclusions cannot be obtained about the incidence of ACCP and histological variety of chronic gastritis. If we do group the patients according to their acid secretory debit, 53 achlorhydric patients had a positiveness of ACCP of 45%, while over 63 with decreased secretory capability, only 18.4%, was positive. The distribution by age groups, shows a major incidence of ACCP about the 4th and 5th decade of life. Thirty seven patients with chronic atrophic gastritis and achlorhydria, and seven with chronic superficial gastritis and hypochlorhydria, besides the antibodies study were on a basal dosage of gastrinemia and antral endoscopic biopsy, finding out that, achlorhydric patients (15 on 19) with normal or slightly altered antrus, have gastrinemia (222 +/- 123 Pgo/oo) and the majority of patients with normal gastrinemia (32 +/- 16 pgo/oo) have more important antral lesions. The ratio between antral histology and ACCP in auto--immune gastritis (Type A), conciliates only partially with the observation by Strickland et al., as only 52.4% of achlorhydric patients and ACCP have a normal antrus or al least with mild lesions. Our results suggest the possibility of that on auto--immune gastritis could act other pathogenic factors of antral lesion.

Adult↗