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Biomedical subjects

R Costa

Publications and source records attributed to R Costa.

At least 127 records · Page 7Linked to original sources
PubMed1992

[Infection by avian chlamydiosis in breeding pigeons in New Caledonia].

An epidemiological survey on avian chlamydiosis, carried out by serological probing in 8 pigeon breeders representative of New Caledonian livestock, combined with bacteriological research on pigeon organs and droppings was set up in New Caledonia in order to determine the prevalence rate of this infection and to adapt sanitary regulations concerning pigeon imports. All sera collected (230) were analysed by complement fixation test (CFT). The organs were diluted in sucrose solution, then stored frozen (-70 degrees C), until inoculation of the yolk-sac of 3 6-8-day-old embryonated eggs (2 blind passages). Yolk-sac smears stained according to the Gimenez method were made in order to detect intracellular chlamydial organisms. Seventeen sera out of 230 were found to be positive, ie 7.4% of the test sample (confidence interval to 95% = 4.0 to 10.8%). The carrier pigeons were significantly more infected (17.8%) than pigeons of other breeds in New Caledonia. These results resulted in the sanitary authorities easing restrictions on imports of seropositive pigeons by imposing a 45-day compulsory quarantine with daily administration of chlortetracycline at the rate of 150 mg per 1 of drinking water.

Animals↗
PubMed1992

[Effects of fenoverine on biliary kinetics evaluated by hepatobiliary scintigraphy with 99mTc-Br-IDA].

Hepatobiliary scintigraphy was used to evaluate the action of fenoverine in 16 patients suffering from dyskinesia of the biliary tract; the drug was administered in doses of 300 mg per day per os for 20 days, the patients being subjected to hepatobiliary scintigraphy before and after treatment. The following parameters--accurate indicators of the motor coordination of the biliary tract--were evaluated: tracer appearance time in the gallbladder (Tc) and in the intestine (Ti). After treatment there was a normalization of these two parameters which initially were extended. Statistical analysis showed a highly significant reduction in these times. Stress is laid on the importance of hepatobiliary scintigraphy in the diagnosis of biliary dyskinesia and on the effectiveness of fenoverine in the treatment of this conditions.

Administration, Oral↗
PubMed1991

[The role of atrial natriuretic factor in cardiovascular physiopathology].

In this review, the authors examine the biochemical mechanism involved in synthesis and release of ANF and its physiological effects concerning kidney and cardiovascular system. In addition, the authors underline the possible interactions of ANF with other hormones, particularly with the renin-angiotensin-aldosterone system and with vasopressin. Finally, the authors consider the possible physiopathological implications of ANF in the genesis of hypertension and hydrosaline retention.

Animals↗
PubMed1991

[Br-IDA in the evaluation of papillo-sphincterotomy and choledochoduodenostomy].

Twenty-three patients who had undergone surgery for non-neoplastic pathologies of the terminal choledochus were studied using 99mTc Br-IDA. This method is used to study patients operated for PST of CDS because: 1) is not invasive and does not cause allergies; 2) it allows a physiological evaluation of biliary flow to be obtained; 3) it is not influenced by the patient's body structure, by the presence of intestinal gas or costo-chondral calcification; 4) the radiation dose absorbed by the patient is very low; 5) it does not require any special preparation of the patient. Papillosphincterotomy was performed in 16 patients and choledochoduodenostomy in 7 patients. Follow-up varied between a minimum of two and maximum of eight years. The morphology of the biliary tract remained normal in all cases or was only slightly dilated. Captation and excretion time remained within normal values. Marker activity in the duodenum appeared early in all cases. A duodenogastric reflux was only observed in one patient among those undergoing PST, whereas it was observed almost constantly following CDS.

Adult↗
PubMed1991

Length polymorphism in the threonine-glycine-encoding repeat region of the period gene in Drosophila.

Single-fly polymerase chain reaction amplification and direct DNA sequencing revealed high levels of length polymorphism in the threonine-glycine encoding repeat region of the period (per) gene in natural populations of Drosophila melanogaster. DNA comparison of two alleles of identical lengths gave a high number of synonymous substitutions suggesting an ancient time of separation. However detailed examination of the sequences of different Thr-Gly length variants indicated that this divergence could be understood in terms of four deletion/insertion events. In Drosophila pseudoobscura a length polymorphism is observed in a five-amino acid degenerate repeat, which corresponds to melanogaster's Thr-Gly domain. In spite of the differences between D. melanogaster and D. pseudoobscura in the amino acid sequence of the repeats, the predicted secondary structures suggest evolutionary and mechanistic constraints on the per protein of these two species.

Amino Acid Sequence↗
PubMed1991

The genotoxicity of nitrilotriacetic acid (NTA) in a somatic mutation and recombination test in Drosophila melanogaster.

The genotoxicity of a chelating agent, the trisodium salt of nitrilotriacetic acid (NTA), was assessed in a somatic mutation and recombination test (SMART) in Drosophila melanogaster employing the wing hair markers mwh and flr3. The experiments were performed in parallel in two different laboratories (Padua, Italy and Schwerzenbach, Switzerland). The effectively absorbed doses of NTA, which was administered by feeding to larvae, were determined by a sensitive method employing [3H]leucine which allowed individual consumption levels to be measured. The particular pattern of clone induction produced by this compound suggests that NTA is active in inducing mitotic recombination and possibly aneuploidy in somatic cells of Drosophila. This is discussed in relation to the data present in the literature regarding the genotoxicity of NTA in a variety of experimental systems.

Animals↗
PubMed1991

Poland's syndrome associated with chronic granulocytic leukemia.

Poland's syndrome has been sporadically associated with haematological neoplasms, namely acute lymphoblastic and myeloblastic leukaemias and non-Hodgkin's lymphomas. The authors present the case of a child in whom this syndrome coexists with a Philadelphia negative, chronic granulocytic leukaemia, which has only required one course of treatment with busulphan in two and a half years of follow-up.

Blood Cell Count↗
PubMed1990

[Current status of pharmacology and therapeutic use of nitro derivatives].

Nitro derivates are effective agents for the treatment of myocardial ischemia. The effectiveness of these compounds in anginal disease is due to their ability to induce dilatation of veins which results in decreased left and right ventricular and diastolic pressure. Furthermore nitro derivates also bring about coronary vasodilatation which is present also in conditions of stenosis of epicardial arteries. In these conditions either coronary flow increases or its redistribution is more favorable. As the vasodilatory effect of nitro derivates does not involve sound arterioles, no "theft" of blood occurs. The dilatation of veins induced by nitrates explains also their effectiveness in patients suffering from heart failure with high left ventricular pressure. Mononitrates seem more effective than dinitrates since variability problems due to hepatic metabolism disappear. Nitrate plasters do not appear favourable since they produce constant blood levels and therefore could favour the development of tolerance.

Angina Pectoris↗
PubMed1990

[Stress and heart].

The interrelation, based on several studies in man and animals, between various types of stressors and the onset of cardiovascular illness have been reported. Physiopathological mechanisms whereby stress seems to be able to damage the heart are described. Finally, the possible therapeutic approaches for "stress related" cardiovascular illness are discussed.

Animals↗
PubMed1990

[Cardiotoxicity of emetine].

Emetine is still an important agent for the treatment of invasive intestinal amebiasis and amebic liver abscess. Its most relevant side effect is its well documented cardiotoxicity. The authors review the hypotheses that have been suggested concerning the mechanism of this cardiotoxic action.

Animals↗
PubMed1990

[Effect of clebopride on gastric emptying studied using a physiologic meal marked with Tc 99m colloid in subjects with non-ulcer dyspepsia].

The authors studied the action of clebopride on gastric emptying in subjects with non-ulcer dyspepsia by using radioactive isotopes. Eighteen subjects complaining of dyspeptic symptoms were studied in whom the tests undertaken had not shown organic lesions of the digestive tract. Tests with radioactive isotopes were performed before and after administration of clebopride (0.5 mg, three times daily for 15 days). In all patients gastric emptying time was normalized and gastric peristalsis became regular. In addition, in 85% of the patients, symptoms disappeared or were markedly reduced. Side effects requiring withdrawal of the drug were not observed. The above study, therefore, showed clebopride to be a useful drug for the treatment of non-ulcer dyspepsia, thus confirming data found in the literature.

Adult↗
PubMed1990

A concerted approach to the study of the aneuploidogenic properties of two chelating agents (EDTA and NTA) in the germ and somatic cell lines of Drosophila and the mouse.

The genetic effects of nitrilotriacetic acid (NTA) and ethylenedinitrilotetraacetic acid (EDTA), two widely used chelating agents, were investigated by using a somatic mutation and recombination test (SMART) after treatment of larvae and the FIX test for aneuploidy after treatment of adult female Drosophila melanogaster. Chloral hydrate (CH) and 5-fluorodeoxyuridine (FdUr) were used as positive controls. Effectively absorbed amounts of the test compounds assayed in Drosophila were estimated at the single fly level by a method using 3H-leucine. NTA and EDTA were also assayed in tests for aneuploidy based on chromosome counting in mouse germ and somatic cells. We previously showed that NTA was able to induce aneuploidy (chromosomal gain) in the germ cells of both Drosophila and the mouse when tested at the exposure levels of 5 x 10(-2) M and 275 mg per kg body weight, respectively [Costa et al., Environ Mol Mutagen 12:397-407, 1988]. In the present experiments, EDTA was assayed at 2.5 x 10(-2) M and 7.5 x 10(-3) M in the FIX test adopting a three-stage brooding scheme. Significant increases (with respect to controls) in chromosomal loss were observed in the second brood and in the combined three-brood total for both exposure levels of EDTA. In the SMART test, treatments with EDTA in the same exposure range produced negative results over all end-points, whereas significant increases in the frequency of small single spots (possibly due to aneuploidy) were produced by NTA 5 x 10(-2) M. In the cytogenetic assays for aneuploidy both in the germ and somatic cells of the mouse, negative results were also obtained following the i.p. administration of 93 and 186 mg EDTA per kg b.w. The previously observed induction of germ cell aneuploidy by NTA (275 mg per kg b.w.) was confirmed in the present experiments on a different strain of mice. NTA (138-275 mg per kg b.w.) did not induce aneuploidy in somatic cells of the mouse [Russo et al., Mutat Res 226: 111-114, 1989], however. These results are compared and discussed with reference to the characteristics of the different test systems used and to the different chelating properties of NTA and EDTA.

Acetates↗
PubMed1990

Enlarged adenomectomy for enclosed prolactinomas: a preliminary study of 26 cases.

Preliminary results obtained from 26 cases of prolactinomas less than 20 mm in diameter after treatment by enlarged adenomectomy are described. The operation consisted in removal of the adenoma, a layer of normal pituitary at the outer edge of the tumour and the pituitary capsule in contact with the sellar meninges. 24 women and 2 men were involved whose prolactin levels (PRL) were less than 200 ng/ml. All presented abnormal PRL responses to Thyrotropin releasing hormone (TRH) and Metoclopramide (MCP) tests and an absence of a nocturnal rise in the sleep cycle study. Postoperatively, three patients developed transitory diabetes insipidus and five transitory adrenal insufficiency. Gonadotropin reserve was always found normal. All 24 women resumed normal menstrual cycles and two became pregnant within one year. From a serological viewpoint, after surgery 100% of patients were found to be normal for levels of prolactin but only 85% turned to normal dynamic tests. The results of this small series of enlarged adenomectomies seem better than those obtained using selective adenomectomy, but must be confirmed with time.

Adolescent↗