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Biomedical subjects

P Valente

Publications and source records attributed to P Valente.

36 records · Page 2Linked to original sources
PubMed1990

Laser assisted fusion of the rat stomach: preliminary studies.

The purpose of this study was (1) to determine whether rat gastrotomies could be securely closed without sutures by CO2 laser-induced tissue fusion alone and (2) to compare some characteristics (physical, biochemical, histological) of laser-fused gastrotomies with sutured gastrotomies. Following pentobarbital anesthesia a 1.5-cm longitudinal anterior gastrotomy was made in the forestomach of male Sprague-Dawley rats. This wound was closed using either a sutureless tissue weld created by a microscope-mounted CO2 laser (153 W/cm2) (Group I, N = 61) or with a running 6-O polypropylene suture (Group II, N = 58). Animals were sacrificed on Postoperative Days 1, 2, 4, 7, and 11 and the wounds were studied. Survival to scheduled sacrifice was 95% in Group I and 93% in Group II. Although bursting pressure of laser-fused gastrotomies was significantly lower than that of sutured controls on Postoperative Day 1, measurement on subsequent days showed comparable wound strength between the laser and suture groups. Wound hydroxyproline content was significantly higher on Postoperative Day 1 and lower on Postoperative Day 11 in the laser group. Histologic examination of the laser-fused wounds revealed less inflammation and earlier reepithelialization than the sutured wounds, giving the microscopic appearance of a "neater" healing wound. These results suggest that laser-induced fusion is a feasible method of gastrointestinal wound closure which may complement standard suture techniques.

Animals↗
PubMed1990

Role of the placenta in perinatal transmission of HIV.

The role of the placental tissue in the perinatal transmission of HIV is still far from being understood. Significant data regarding transplacental infection have been collected, but differences in technique have led to controversy. It appears clear that many Hofbauer cells are CD4+ and can become infected with HIV. Less certain but probable is infection of trophoblasts themselves. Whether infection is CD4 mediated or via cell-cell fusion is not established. Transplacental traffic of virus and cells remains a little-studied possibility. Further data are needed regarding the fascinating concept of the placenta as a modulator of infection.

Female↗
PubMed1989

Carcinogenic risk assessment: some comparisons between risk estimates derived from human and animal data.

Carcinogenic risk assessment may be based on epidemiological as well as experimental data; the aim of the present study is to compare these two procedures and to verify the efficiency of some animal bioassays for the prediction of tumor incidence and relative risk in man. The predictability obtained from animal models has been found to be fairly consistent with the data obtained from epidemiological studies.

Animals↗
PubMed1978

Acute leukopenia associated with silver sulfadiazine therapy.

A patient with a 30% scald burn was treated with topical silver sulfadiazine (Silvadene). On two occasions, within 48 hours of treatment, the patient developed acute leukopenia. Bone marrow aspiration revealed cell maturation arrest. The possible mechanisms of this leukopenia are discussed. It is recommended that daily leukocyte counts be done in burn patients being treated with silver sulfadiazine.

Acute Disease↗
PubMedDate not supplied

Effects of coffees before and after special treatment procedure on cell membrane potentials in stomach cells.

Coffee, one of the most excessively used beverages worldwide, commences the risk of gastroesophageal reflux (GER), which may lead to gastric ulcers and increase the risk of gastric cancer. Many attempts have been made by the coffee industry to diminish the irritating effect on mucosa by means of altering the extraction methods concerning gerbic acids and the roasting processes. This paper describes the effect of differently produced coffees involving two brands of Darboven and two brands of other coffee roasters. The aim of this study was to prove the results of gastric potential measurements we found in literature by using human AGS gastric epithelial cells (human adenocarcinoma). All four coffee extracts tested differentially affected the membrane resting potential of AGS cells. Coffees no. 1 and no. 2 depolarized the cells, presumably by increasing the cation entry into the cytosol. In marked contrast, coffee no. 4 hyperpolarizes the cells, possibly by H(+) extrusion and/or Cl(-) influx, suggesting that this coffee might increase acidity in the stomach, which might negatively affect the stomach, especially in people with gastroesophageal reflux symptoms. Overall, our data suggest that different roasting methods of coffees affect the membrane potentials of AGS stomach cells, resulting in increased influx of H+ possibly resulting in decreased stomach acidity and thus reducing GER. These results are in good accordance with clinical pharmacological results from potential difference measurements in healthy volunteers we found in the literature.

Adenocarcinoma↗
PubMedDate not supplied

[Juvenile cutaneous polyarteritis nodosa associated with streptococcal infection].

Polyarteritis nodosa is a rare vasculitis of small and medium arteries. It can occur in a systemic form with multi-organ involvement, or as a limited form confined to the skin, muscles, joints and peripheral nerves called cutaneous polyarteritis nodosa. Both forms are rare in adults and even more in children. The caues of this vasculitis remain unknown but some viruses and bacteria have been implicated, specially, Streptococcus. We present the case of a 6-year-old child who developed cutaneous polyarteritis nodosa following a probable streptococcal infection.

Child↗
PubMedDate not supplied

In utero diagnosis of congenital infections by direct fetal sampling.

Counseling for infections during pregnancy has traditionally focused on the clinical and laboratory findings of infection in the mother and the estimated risk of fetal damage associated with possible transmission of infection to the child. Now, with the use of techniques for fetal sampling, it is possible to diagnose infections of the fetus in utero and to correlate that information with the occurrence of fetal damage. The techniques that are available for sampling include amniocentesis, cordocentesis and chorionic villus sampling. The laboratory tests include: a) isolation of the organism in appropriate laboratory systems; b) detection of the DNA or RNA of the organism directly or with amplification with techniques such as PCR; c) detection of the organism by fluorescence or in situ hybridization; and d) identification of IgM or IgA fetal antibody to the organism by ELISA or similar methods. In utero infections can be documented for agents such as rubella, cytomegalovirus, parvovirus, Toxoplasma gondii and human immunodeficiency virus type 1. Further information is needed concerning the sensitivities and specificities of these methods for identifying fetal infection and predicting fetal damage.

Amniocentesis↗
PubMedDate not supplied

Early diagnosis and immunologic changes in HIV-1 infected pregnant women and their children.

The diagnosis of HIV infection in pregnant women is usually based on the detection of HIV-specific antibodies. These tests become positive a few weeks to months after infection. In the United States, it is recommended that tests be offered to all women and encouraged where the rate of infection is > or = 1/1,000 or the woman is at increased risk for infection. The great majority of infected pregnant women are asymptomatic, and questioning patients about risk behavior will identify only about one-half of the infected women. In Washington, D.C. about 1.5% of the pregnant women who reside in the city are HIV positive. The diagnosis of HIV in the child in the first month of life is difficult and requires the use of polymerase chain reaction tests and/or culture. Other tests become positive later. Immunological tests in most HIV-infected mothers in the USA are normal; however, about 12% of patients are symptomatic and show decreased CD4 T cell counts and 6% have AIDS. These patients may have other evidence of decreased T cell responses and are at increased risk for opportunistic infections. At birth, almost all children of HIV-infected mothers have normal immunological findings. However, about 50 of these children become ill by 1 year of age and many develop decreased T cell counts and other immunological changes.

Female↗
PubMedDate not supplied

[Tuberculosis: a forgotten challenge].

Tuberculosis continues to be a serious problem in public health even thought eh causative bacillus was discovered over 100 years ago. The authors present a clinical case that illustrates the current concern regarding the disease. The case concerns a child of emigrant parents, who are drug addicts and whose illness has not been fully ascertained. The child was hospitalised at three and an half months with fever, malnutrition, opisthotonos and hepatosplenomegaly. After the diagnosis of disseminated tuberculosis affecting the central nervous system, treatment was started with five antituberculosis drugs and with corticosteroids. Respiration improved favourably, but after 19 days the patient suffered a partial tonic-clonic seizure. Subsequently, hydrocephalus was observed and a shunt was applied. Bacteriological examination of the gastric aspirate showed a strain of Mycobacterium tuberculosis resistant to isoniazid and streptomycin. In the eight month of therapeutics, three antituberculosis drugs were still being administered, the shunt was still present and the patient showed a severe psychomotor retardation. The child belonged to a risk group and presented a serious form of tuberculosis with multidrug-resistance, illustrating that this group of children is particularly vulnerable and reflect transmission of this illness among adults.

Central Nervous System Diseases↗
PubMedDate not supplied

[Cerebrovascular diseases in Portugal: some epidemiological aspects].

The Portuguese population is affected by the highest mortality rates in all the countries of the European Union. The highest mortality rates occur in some districts on the north coast where, in 1995, the rates standardised by age were above 200/100,000/annum, with the lowest figures in some districts in the interior and in Lisbon. These mortality rates have had a downward trend, but inferior to what is desired, or what occurs in other developed countries. The Autonomous Region of Madeira had a more significant percentage reduction (40%), followed by the Autonomous Region of the Azores (25%). Little is known of the effects of sporadic occurrences on the mortality associated to cerebrovascular disease. The consequences of two of these occurrences are described: the heat wave in June 1981 and the influenza epidemic in 1988-89. The number of deaths due to cerebrovascular diseases in the period corresponding to the heat wave was 2.2 times higher than expected, while during the influenza epidemic cerebrovascular diseases were the most common cause of death (25.8%) contributing to excess mortality. It is imperative that instruments be created to more accurately estimate the importance of this group of diseases in Portugal in what concerns incidence, resulting disability and health care requirements as well as social and financial costs for the individuals, the families and the community.

Age Distribution↗