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Biomedical subjects

V Castro

Publications and source records attributed to V Castro.

At least 37 records · Page 2Linked to original sources
PubMed1999

Frequencies of platelet-specific alloantigen systems 1-5 in three distinct ethnic groups in Brazil.

The human platelet antigen (HPA) systems are related to immune platelet disorders as well as to the development of occlusive vascular disease. Several distinct biallelic HPA systems are known, and a heterogeneous distribution of HPA alleles has been described among distinct ethnic groups. In this study we genotyped 320 carefully selected individuals from three distinct ethnic groups in Brazil (Caucasians, Blacks and Amazonian Indians) for the HPA-1, -2, -3, -4 and -5 systems. A similar prevalence for all HPA alleles was found in Brazilians of Caucasian and Black descent. These data contrast with those reported for similar ethnic groups in other countries. Among the Amazonian Indians, no b allele of the HPA-1, -4 and -5 systems was identified. The data presented here could be useful in the diagnosis of alloimmune platelet disease, in genetic counselling and in the development of screening programmes for HPA-related diseases.

Adolescent↗
PubMed1999

Primary amyloidosis presenting as extensor tenosynovitis.

Primary amyloidosis is a systemic disease. Amyloid arthropathy is an invalidating and uncommon form of presentation, but tenosynovitis is even rarer as the first sign of the disease. We report herein a case of unilateral amyloid deposit in the synovium of the extensor tendons of the hand, which was the first manifestation of a primary amyloidosis.

Aged↗
PubMed1998

Study of three sesquiterpene lactones from Tithonia diversifolia on their anti-inflammatory activity using the transcription factor NF-kappa B and enzymes of the arachidonic acid pathway as targets.

In Central America leaf extracts from the Asteraceae Tithonia diversifolia are used externally for the treatment of haematomas and wounds. Therefore, the main sesquiterpene lactones (Sls) of this species growing in Costa Rica, diversifolin (1), diversifolin methyl ether (2), and tirotundin (3), were studied for their anti-inflammatory activity. We determined whether these compounds inhibit cyclooxygenase-I, phospholipase A2, or the transcription factor NF-kappa B. Here we show that these Sls do not influence the enzymes of the arachidonic acid pathway, but inhibit the activation of NF-kappa B. Thereby, the synthesis of inflammatory mediators such as cytokines and chemokines is reduced. Our results indicate that the inhibitory activity of compounds 1-3 is due to alkylation of cysteine residues, which are probably located in the DNA binding domain of NF-kappa B. The Sls were also studied for their antibacterial activity, but only Sl 1 was moderately active against Bacillus subtilis in the agar plate diffusion test.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Reconstruction of pharyngostomes with a modified deltopectoral flap combining endoscopy and tissue expansion.

The problem of pharyngostomic closure is difficult to solve, as evidenced by the large number of techniques described. The authors present the reconstruction of pharyngostomes by using Bakamjian's deltopectoral flap modified by the use of endoscopically introduced expanders for those patients in whom other techniques of choice (such as vascularized free flaps) have failed or are inapplicable either because of previous radiotherapy or because of local conditions. Bakamjian's deltopectoral flap, previously expanded with an expander coated with a partial-thickness skin graft and introduced endoscopically, allowed the authors to lift the flap in one operation to close the pharyngostome. This method provides the two walls of the pharynx (the skin graft as the inner aspect and the skin flap as the outer aspect), and the donor deltopectoral area is covered and epithelialized due to the skin graft. Thus by means of endoscopic expansion we use a nonaggressive technique to increase the surface area of the donor site and to increase its vascularization (delay phenomenon). Because the expander was coated with the graft, the authors were able to cover the anterior wall of the pharyngostome and the donor site in one surgical step.

Aged↗
PubMed1998

Transconjunctival herniation of orbital fat.

The authors present 3 patients with subconjunctival fat prolapse treated at their oculoplastic unit. Albeit rare, orbital fat is a well-recognized entity, and is described in the literature as being associated with trauma and surgery. The 3 patients reported herein, however, presented with no history of trauma or surgery. This condition is produced by herniation of the intraconal fat between the conjunctiva and the sclera, presumably due to dehiscence of the Tenon's capsule. Differential diagnosis should be made with lacrimal gland ptosis, lacrimal gland tumors, and lymphoid tumors.

Adipose Tissue↗
PubMed1997

Effects of four organohalogen environmental contaminants on cytochrome P450 forms that catalyze 4- and 2-hydroxylation of estradiol in the rat liver.

The four environmental pollutants studied (3,3',4,4',5-pentachlorobiphenyl, 2,2',4,4'-tetrabromodiphenyl ether, Tris-(p-chlorophenyl)methanol, and 3,4,5-trichloroguaiacol) were all found to induce a significant increase in 4-hydroxylation of estradiol activity in male rat liver microsomes. However, only 3,3',4,4',5-pentachlorobiphenyl was found to significantly increase 4- and 2-hydroxylation of estradiol in female rat liver microsomes. 4-Hydroxylation has been suggested to be responsible for the development of estrogen-dependent tumors and, therefore, it cannot be excluded that these pollutants can be a risk for the development of estrogen-dependent tumors in humans and wildlife.

Animals↗
PubMed1997

Increased thyrotrophin levels and loss of the nocturnal thyrotrophin surge in Sheehan's syndrome.

OBJECTIVE: Since panhypopituitarism in patients with Sheehan's syndrome is due to massive pituitary necrosis with only minor hypothalamic involvement, we hypothesized that serum TSH levels would be low but its circadian rhythm preserved in these patients. DESIGN AND PATIENTS: Basal and TRH-stimulated mean afternoon (1500-1700 h) and nocturnal (0100-0300 h) TSH levels were determined in 10 patients with Sheehan's syndrome before and during T4/glucocorticoid replacement and in seven controls. MEASUREMENTS: Serum concentrations of T3, T4, free T4 (fT4) and cortisol were measured by radio-immunoassay; TSH, GH, PRL and LH were determined by immunofluorimetric assay. RESULTS: Afternoon TSH levels were markedly increased in Sheehan's syndrome patients compared with controls (3.3 +/- 1.0 vs 0.5 +/- 0.15 mU/l, respectively, P = 0.002). At night, TSH levels remained unchanged in Sheehan's syndrome patients (3.3 +/- 1.1 mU/l) but rose significantly in controls (1.1 +/- 0.34 mU/l, P = 0.016). The nocturnal TSH increment was significantly higher in controls than in patients (143 vs approximately 4.9%, respectively, P = 0.0001). In eight patients with normal serum fT4 levels during treatment, basal TSH levels decreased to 0.16 +/- 0.05 mU/l (P < or = 0.008), being barely detectable or undetectable in four patients. In the six patients with detectable TSH during treatment, nocturnal TSH increments were normal in four and blunted in two. There was a strong correlation between pre- and post-treatment basal TSH (r = 0.82, P = 0.012) and between pre- and post-treatment peak TSH after TRH (r = 0.91, P = 0.0017), but no significant correlation between TSH and thyroid hormone levels. The per cent ratio of peak TSH after TRH between treated patients and controls, an estimate of the relative size of the functional thyrotroph pool in Sheehan's syndrome patients, was 7%. CONCLUSIONS: Loss of TSH rhythm in Sheehan's syndrome is usually secondary to hormonal deficiency and results from maximally increased secretory activity of a decreased pool of thyrotrophs. The paradox of increased TSH levels and decreased thyroid function in Sheehan's syndrome could result from decreased TSH bioactivity and/or from a critically reduced thyrotroph population that fails to sustain sufficient TSH secretion in the face of rising serum thyroid hormone levels.

Adult↗
PubMed1997

Dose-response studies of interferon-alpha 2b on liver fibrosis and cholestasis induced by biliary obstruction in rats.

Interferons have been utilized widely in chronic liver diseases for their antiviral properties. In addition, there is evidence for their antifibrogenic actions. In this work we studied effects of various doses of interferon-alpha 2b on experimental liver fibrosis and cholestasis induced in the rat by biliary obstruction. Collagen was measured as hepatic hydroxyproline content. Cholestasis was determined by serum alkaline phosphatase and gamma-glutamyltranspeptidase activities and by bilirubin content. Glycogen was measured in the liver. Interestingly, the best effects (antifibrotic and anticholestatic) were observed in the group receiving the lowest dose of interferon. These results suggest that interferon-alpha 2b may be used at low doses, thereby decreasing side effects and costs.

Animals↗
PubMed1996

Neoadjuvant and adjuvant chemotherapy in the multidisciplinary treatment of oral cancer stage III or IV.

We performed a retrospective analysis on the effect of initial induction chemotherapy with two courses of cisplatin (each course 120 mg/m2 cisplatin on day 1, then 20 mg/m2 bleomycin (alone) per day for 5 days with 4 weeks between courses) in 75 consecutive patients with advanced cancer of the oral cavity or lip. Further local therapy consisted of surgery or radiation, depending on tumour location. In 18 resected patients adjuvant chemotherapy was added. This consisted of carboplatin, 400 mg/m2 on day 1 then ftorafur alone, 500 mg/m2/day for 30 consecutive days, repeated every month for 4 consecutive months. Among the patients treated in the neoadjuvant setting, complete response was observed in 10 out of 75 patients (13%), and partial response in a further 50 patients (67%) (partial plus complete rate 80%). Of all the patients, 43% in stage III and 26% in stage IV were long-term survivors. Improved survival was observed in surgical patients where adjuvant postoperative chemotherapy was added (P < 0.025). The main toxic effect was vomiting, observed in 71 patients. We noted a low rate of stomatitis (4%) and an important hearing loss (12%). Neoadjuvant and adjuvant cisplatin-based chemotherapy as part of a multidisciplinary approach have a high overall response rate and low toxicity, and should increase survival in cancer of the oral cavity or lip.

Adult↗
PubMed1994

Carboplatin plus ftorafur as a palliative treatment in locally advanced cancer of the oral cavity and lip.

Forty consecutive patients with local advanced cancer of the oral cavity and lip, heavily pretreated, were palliated with two courses of carboplatin, 400 mg/m2 intravenously once a month plus ftorafur, 500 mg/m2 daily per os for 30 days. Previous treatment consisted of surgery (17 patients), radiation therapy (23 patients), and chemotherapy with cisplatin plus bleomycin (15 patients). The main sites of primary tumor were the tongue (12 patients), hard palate (6 patients), retromolar area (6 patients), tonsils (6 patients), perioral skin and lip (5 patients), and floor of the mouth (5 patients). Complete response was observed in 3 patients, and partial response in 7. Symptomatic improvement was observed in 56% of the cases. Median duration of response was 9 months. Median survival was 7 months. The main toxic effects were nausea (39 cases), vomiting (35 cases), and thrombocytopenia (4 cases). We conclude that carboplatin plus ftorafur has a role as palliative chemotherapy in cancer of the oral cavity and lip in heavily pretreated patients when local therapies are not suitable.

Adult↗
PubMed1993

Expression of epidermal growth factor receptor (proto-oncogene c-erbB-1) and estrogen receptor in human breast carcinoma. An immunocytochemical study of 70 cases.

In vitro studies have shown that growth factors may mediate the growth stimulatory effect of estrogen in hormone-dependent human breast carcinomas while the constitutive expression of same growth factors might by-pass the need for estrogenic stimulus in hormone-independent neoplasms. We have performed immunocytochemical analysis of the expression of epidermal growth factor receptor (EGF-R or proto-oncogen c-erbB-1) and estrogen receptor (ER) in 70 cases of human breast carcinoma. We found an inverse relationship between the expression of EGF-R and ER (Kendall's tau b = -0.1997, P < 0.03), which prompts us to conclude that ER(-) breast carcinomas may grow in a hormone-independent manner through the over-expression of the proto-oncogene c-erbB-1, which is the receptor for epidermal (EGF) and alpha transforming (TGFalfa) growth factors.

Aged↗
PubMed1989

[Treatment of tubal pregnancy by laparoscopy].

Three cases of ectopic pregnancy early diagnosticated are treated successfully with laparoscopic fulguration. Useful of this procedure is discussed and the needs of more experience is suggested.

Adult↗