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Biomedical subjects

J C Carvalho

Publications and source records attributed to J C Carvalho.

At least 37 records · Page 2Linked to original sources
PubMed1997

Hypoxia and response of human umbilical artery strips to 5-hydroxytryptamine: role of prostaglandin F2 alpha.

1. This article examines the effects of hypoxia on the contractile response of isolated human umbilical artery strips to 5-hydroxytryptamine (5-HT). 2. Hypoxic conditions produce a large increase in the contractile response to 5-HT without a significant alteration of the sensitivity evaluated at the level of the pD2 value. Indomethacin (10 microM) reduced hypoxia-induced potentiation of the response to 5-HT and decreased the response to the monoamine under oxygenated conditions. 1-NAME (100 microM) did not further increase the effect of hypoxia on the vessel response to 5-HT and increased the response to 5-HT under oxygenated conditions. 3. Taken together, these results suggest that, at least partially, the response of human umbilical artery strips to 5-HT depends on 5-HT release of a contracting prostanoid which is a product of the cyclooxygenase pathway. Furthermore, during hypoxia in human umbilical artery strips, there appears to be impairment of the basal production and/or release of EDRF/NO. 4. A subthreshold concentration of prostaglandin F2 alpha (1 nM) potentiates the response to 5-HT in indomethacin-pretreated umbilical artery strips. The data raise the possibility that prostaglandin F2 alpha might be the prostanoid released during hypoxia, which in turn potentiates the response of the human umbilical artery to 5-HT.

Cell Hypoxia↗
PubMed1997

Effects of simulated myocardial ischemic conditions on the responses of isolated human umbilical artery strips to 5-hydroxytryptamine and prostaglandin F2 alpha.

1. The effects of simulated myocardial ischemic conditions on the contractile response of isolated human umbilical artery (HUA) strips to 5-hydroxytryptamine (5-HT) and prostaglandin F2 alpha (PGF2 alpha) were studied. 2. During simulated myocardial ischemic conditions the contractile response of HUA strips to 5-HT was lower than the response to the monoamine under oxygenated conditions. Under simulated ischemic conditions the response to 5-HT was further depressed by the cyclooxygenase inhibitor indomethacin (10 microM) and increased by the NO synthase inhibitor L-NAME (100 microM). 3. During simulated ischemic conditions the response of the HUA to a submaximal concentration of PGF2 alpha (3 microM) was reduced. Indomethacin (10 microM) further reduced the response to the prostanoid whereas L-NAME (100 microM) enhanced the response to PGF2 alpha. 4. It is concluded that during simulated myocardial ischemic conditions lactate negatively modulates the contractile response of HUA strips to 5-HT. Apparently, during simulated myocardial ischemic conditions in the HUA the production and/or release of EDRF/NO was not affected.

Culture Media↗
PubMed1997

Endogenous thromboxane A2 does not contribute to the contractile response of human umbilical artery strips to 5-hydroxytryptamine.

1. To investigate the possible role of endogenous thromboxane A2 (TXA2) in 5-hydroxytryptamine (5-HT)-induced contraction, human umbilical artery strips were suspended in isolated organ chambers for measurement of isometric force. 2. In endothelium intact strips, arachidonic acid (AA;1 microM) potentiates the contractile response to 5-HT, whereas the response was reduced by indomethacin (INDO;10 microM). De-endothelialized strips showed reduced responses to 5-HT. 3. Arachidonic acid-induced potentiation of the responses to 5-HT was prevented by INDO, and the TXA2 synthase inhibitor dazoxiben (DAZ;1 microM and 10 microM) was without effect on the responses to 5-HT in endothelium intact strips. 4. Taken collectively, these results suggest that, in human umbilical artery strips, the contractile response to 5-HT is at least partly dependent on the 5-HT induced release of an endothelium-derived contracting factor (EDCF), which is a cyclooxygenase metabolite. The lack of effect of DAZ indicates that TXA2 is not the EDCF released during the contractile response of human umbilical artery strips to 5-HT.

Endothelins↗
PubMed1996

Preliminary studies of analgesic and anti-inflammatory properties of Caesalpinia ferrea crude extract.

The crude aqueous extract of the fruits of Caesalpinia ferrea Mart. (Leguminosae) has been investigated for possible anti-inflammatory and analgesic properties. The carrageenan induced rat hind paw edema was significantly inhibited (P < 0.05) by oral administration of 300 mg/kg of this extract. A centrally mediated analgesic effect was not observed, however, there was a dose dependent reduction in the number of total writhes induced by acetic acid.

Acetic Acid↗
PubMed1996

Investigation of anti-inflammatory and antinociceptive activities of trans-dehydrocrotonin, a 19-nor-clerodane diterpene from Croton cajucara. Part 1.

The anti-inflammatory and antinociceptive effects of trans-dehydrocrotonin, isolated from the bark of Croton cajucara (Euphorbiaceae), were investigated using several animal models. The trans-dehydrocrotonin produced a significant inhibition of carrageenin-induced paw edema and cotton pellet granuloma in rats. It also inhibited the writhings in mice induced by acetic acid, but did not show a significant effect in the hot-plate test in mice. The LD50 of t-DCTN was 555.0 mg/kg (p.o.) for mice.

Analgesics↗
PubMed1996

Noise and the quality of sleep in two hospitals in the city of Belo Horizonte, Brazil.

Male patients of two hospitals in Belo Horizonte completed a questionnaire during an interview on the day of discharge in order to evaluate sleeping conditions related to noise during the previous night and were retested 24 h later. Patients had a worse perception of sleep at the noisier hospital, the University Hospital of the Federal University of Minas Gerais (N = 13), whose internal mean nocturnal noise level was Leq = 53.7 db(A), than at the quieter hospital, Baleia (N = 22), whose internal mean nocturnal noise level was Leq = 45.5 db(A). Noise was the only sleep-disturbing factor which was statistically significant.

Adolescent↗
PubMed1994

Restorative caries treatment patterns in Danish 20-year-old males in 1986 and 1991.

This study examines the restorative caries treatment pattern in Danish 20-year-old military conscripts in 1986 and 1991. The study groups comprised 85 and 164 males born in 1966 and 1971, respectively. The examination was performed as a part of the routine for each conscript according to directions from Dental Service, Danish Defense Forces and included surface recording of fillings on all teeth except third molars. Two bitewing radiographs were taken of all conscripts in the 1986-group and of those who gave permission (59) in the 1991-group. The mean number of filled surfaces was 10.2 and 8.8 in 1986 and in 1991, respectively. 80% of the occlusal surfaces on permanent first molars were filled in the 1986-group and filled or sealed in the 1991-group in contrast to 45% of permanent second molars. Data from maxillary molars indicated a tendency to placement of fillings related to tooth specific morphology whereas extended fillings involving the entire occlusal surface dominated on mandibular molars. The X-ray examination disclosed that the majority of approximal molar surfaces were classified as sound in both study groups. Less than 1% of the approximal molar surfaces were recorded as having lesions penetrating deep into the dentin. In 1981 and in 1986 the participants in the study groups were 15 yr old. In these years the mean number of filled surfaces in Danish children amounted to 11.0 and 6.9 respectively, which indicates that very few lesions in need of operative treatment developed from age 15 to age 20 in both study groups.

Adolescent↗
PubMed1994

Light-weight ocular prosthesis.

The authors propose a variation of the technique for making ocular protheses for large ophthalmic cavities introducing an expanded polystyrene (styrofoam) to the acrylic resin at the time of making the prosthetic sclera, aiming at reducing the weight of the prosthesis and thus improving mobility and aesthetics. This study compares the differences in weight, absorption of water and resistance to rupture by hydrostatic pressure of the pieces made of acrylic resin, chemically activated, heat activated and cross-linked by the proposed technique and by the technique for hollow ocular prothesis. The proposed technique presents advantages in manufacturing time and handling of the material.

Acrylic Resins↗
PubMed1993

Dental plaque and caries on permanent first molar occlusal surfaces in relation to sagittal occlusion.

This study examines the influence of sagittal occlusion on occlusal plaque formation in permanent first molars (PFM) in 72 7-10-yr-olds before loss of primary second molars. Of a total of 288 PFM, 140 (49%) were sealed and 23 (8%) filled. Occlusal plaque was recorded at two levels of examination: 1) visible plaque on the entire surface and 2) detailed macromorphologic mapping. Enamel caries was recorded after professional tooth cleaning. After 48 h without tooth brushing, plaque examinations were repeated. Stone models were used for 1) identification of interocclusal contact areas and 2) classification of sagittal molar occlusion. The detailed mapping of plaque on unfilled surfaces showed a clear pattern of preferential locations related to the macromorphology of the occlusal surfaces. Active caries was restricted to those anatomic structures where plaque accumulated. 48-h median plaque values on mandibular molars in normal and with one cusp distal occlusion were significantly lower (P < 0.01) compared to surfaces in 1/4, 1/2 and 3/4 distal molar occlusion. Maxillary molars with normal and with 1 cusp distal occlusion had lower median plaque values than other sagittal occlusion categories. In general, however, plaque scores were higher in maxillary teeth because more than 2/3 of these teeth were without occlusal contact in the distal part. Mandibular occlusal surfaces in normal and with one cusp distal occlusion had significantly fewer active lesions than teeth with 1/4, 1/2 and 3/4 cusp distal occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Chi-Square Distribution↗
PubMed1992

Results after 3 years of non-operative occlusal caries treatment of erupting permanent first molars.

The aim of the study was to describe the 3-yr results of a treatment program designed to control occlusal caries on the basis of intensive patient education and professional toothcleaning. The sample consisted of 56 children 6-8 yr old with their permanent right first molars in different stages of eruption. The results were compared with record data from 58 children of the same age who had received a traditional caries treatment program including fissure sealing (control group). After 1 yr a significant reduction of occlusal surfaces with visible plaque was noted in the study group as well as an increased proportion of arrested lesions. These results were maintained after 2 and 3 yr. Ten (9%) teeth were sealed and one filled during the study period. Examination of record data in the control group over a 3-yr period revealed that 76 (65%) first molars were sealed and 7 (6%) were filled. During the first year 1/3 of the children in the study group needed 5-6 recall visits, whereas in the following period all children were only seen 1-4 times. In contrast, 50% of the children in the control group needed 5-6 recalls in the 3rd yr. Our data indicate that professional care for erupting teeth on an individual basis has a long-term effect on occlusal surfaces as well. The alternative technique required less clinical time than the traditional application of sealants.

Child↗
PubMed1991

Results after 1 year of non-operative occlusal caries treatment of erupting permanent first molars.

The aim of this study was to evaluate a treatment program designed to control occlusal caries on the basis of intensive patient education and professional toothcleaning. The sample consisted of 56 6-8-yr-old children with their permanent right first molars in different stages of eruption. Data from the program were compared with previous data recorded in a similar sample of children. After 1 yr the majority of children in the study group had their permanent right first molars in full occlusion. A significant decrease of surfaces with easily detectable plaque and an increase of surfaces without plaque was observed. The proportion of arrested lesions increased and active enamel lesions decreased. Fissure sealing was only needed in two teeth in contrast to more than 2/3 of molars in a comparable sample of children. The program proved to be an efficient alternative to fissure sealing in preventing occlusal caries in erupting teeth.

Child↗
PubMed1989

Dental plaque and caries on occlusal surfaces of first permanent molars in relation to stage of eruption.

The occlusal surfaces of partly and fully erupted first right permanent molars were examined with respect to the occurrence and distribution of plaque and dental caries in a group of 57 six- to eight-year-old children. The children were classified into four groups ranging from one tooth partially erupted to full occlusion. Occlusal plaque was recorded at two levels of examination: (1) visible plaque and (2) detailed mapping by means of a plaque detector system. Dental caries was recorded after professional cleaning. The recording of plaque was repeated after 48 hr without oral hygiene. The findings showed a significant reduction in the easily detectable plaque in fully erupted teeth, compared with the three groups representing partly erupted teeth. The detailed mapping of plaque showed a clear pattern of preferential locations related to the macromorphology of the occlusal surfaces, and revealed reduction in the frequency of thick plaque accumulation in the fully erupted teeth. The proportion of active lesions was reduced in fully erupted teeth, and arrested lesions were mainly observed in the same group. This indicated that erupting teeth are more likely to develop dental caries, due to favorable conditions for plaque accumulation. Functional usage of teeth in addition to improved access for toothbrushing promoted arrestment of lesions initiated during eruption.

Child↗