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Biomedical subjects

M Carvalho

Publications and source records attributed to M Carvalho.

At least 37 records · Page 2Linked to original sources
PubMed2000

Reversible sympathetic vasomotor dysfunction in POTS patients.

BACKGROUND: Orthostatic intolerance refers to the development upon assuming an upright posture of disabling symptoms, which are partly relieved by resuming the supine position. Postural tachycardia syndrome (POTS) is an orthostatic intolerance syndrome characterized by palpitations due to excessive orthostatic sinus tachycardia, lightheadedness, tremor, and near-syncope. Patients usually undergo extensive medical, cardiac, endocrine, neurological and psychiatric evaluation, which usually fails to identify a specific abnormality. We investigated the autonomic and hemodynamic profile of POTS patients and the efficacy of bisoprolol and or fludrocortisone. METHODS AND RESULTS: We evaluated eleven female patients with POTS before and after medical treatment with a cardio-selective beta blocker (bisoprolol) and/or fludrocortisone, and eleven age-matched controls. Variability of heart rate and systolic blood pressure was assessed by Fast Fourier Transform, and spontaneous baroreceptor gain by temporal sequences slope and alpha index. Modelflow was used to quantify hemodynamics. All patients improved greatly after medication. The autonomic and hemodynamic impairment observed in patients with POTS, particularly after orthostatic stress, is treated effectively with bisoprolol and/or fludrocortisone. These results need further confirmation in a controlled double-blind study. CONCLUSIONS: Proper medical treatment dramatically improves the clinical and autonomic/hemodynamic disturbances observed in patients with POTS. The data support the hypothesis that POTS is due to a hyperadrenergic activation and/or hypovolemia during orthostasis.

Adolescent↗
PubMed2000

Role of autonomic nervous system and hemodynamics in cardiovascular homeostasis after orthostatic stress.

Autonomic control of hemodynamics is crucial to maintaining cardiovascular homeostasis after orthostasis. Our goal was to assess the effect of passive orthostatic stress on cardiovascular hemodynamics regulation by analysis of the autonomic nervous system (ANS) and gender influence on the variables. We used a passive 70 degrees tilt test as an orthostatic maneuver. For SNA measurements we used FFT for HRV and SBPV, temporal sequences and alpha index to calculate baroreceptor gain. Hemodynamic data was calculated non-invasively by modelflow. Orthostatic stress induces a rise in heart rate (+15%), total peripheral resistance (+28%), sympathetic tonus (LF_nu: +32%; LF_pas: +64%) and a reduction in cardiac output (-28%), systolic volume (-43%), and vagal activity both tonic (HF_nu:-115%) and reflex (BRG:-103%). Females had higher vagal activity regardless of position. We concluded that the autonomic nervous system plays a crucial role in cardiovascular hemodynamics control to maintain homeostasis after orthostatic stress.

Adult↗
PubMed1999

Population distribution of six PCR-amplified loci in Madeira Archipelago (Portugal).

Frequency data of the short tandem repeat (STR) loci HUMTH01, HUMVWA31/A, HUMF13A1, HUMFES/FPS, D12S391 and HUMFIBRA/FGA were determined in blood stains obtained from a population of unrelated individuals from the Madeira Archipelago. The observed genotype distribution showed no significant deviation from the Hardy-Weinberg equilibrium and there was no evidence for association of alleles among the six loci. Population data showed a combined discrimination power of 0.9999998 and a chance of exclusion of 0.99597. The frequencies are similar to those of other compared caucasian populations but significant differences were found between the Madeira population and Japanese, Chinese, Greenland Eskimos and Quechua Amerindians. The six loci studied, together proved to be highly discriminating and valuable for forensic cases.

Blood Stains↗
PubMed1999

Pemphigus vulgaris: benefits of tetracycline as adjuvant therapy in a series of thirteen patients.

BACKGROUND: Tetracycline is an antibiotic which has been proven beneficial as an immunomodulating drug in the treatment of autoimmune bullous diseases. METHODS: Thirteen hospitalized patients with pempigus vulgaris received tetracycline 2 g/day for 1 month, then 1 g/day for the following 4 weeks. Prednisone 0.5-1 mg/kg/day was then gradually reduced. The control group consisted of seven patients with pemphigus who had received prednisone and azathioprine. RESULTS: A total of 13 patients in the study group achieved cessation of new blister formation within 5.4 days, compared to 23.71 days (p < 0.0001). The average initial dose of prednisone was 76.53 mg/day for the study group and 118.57 mg/day in the control group (p < 0.014). The average number of days before reduction of the prednisone dosage could begin was 16.53 days for the study group compared to 31.28 days in the control (p < 0.049). Total hospitalization time was also significantly lower: 34.07 days (p < 0.001). The clinical response was not linked to the location of lesions nor to severity of disease. CONCLUSIONS: Tetracycline was shown to be effective as an adjuvant therapy for pemphigus with low toxicity and safety.

Adult↗
PubMed1999

Relationship between cell surface carbohydrates and intrastrain variation on opsonophagocytosis of Streptococcus pneumoniae.

Streptococcus pneumoniae undergoes spontaneous phase variation between a transparent and an opaque colony phenotype, the latter being more virulent in a murine model of sepsis. Opaque pneumococci have previously been shown to express lower amounts of C polysaccharide (cell wall teichoic acid) and in this study were shown to have a higher content of capsular polysaccharide by immunoelectron microscopy. This report then examined the relationship between expression of these two cell surface carbohydrate structures and their relative contribution to the increased virulence of opaque variants. Comparison of genetically related strains showed that the differential content of capsular polysaccharide did not affect the amount of teichoic acid as measured by a capture enzyme-linked immunosorbent assay (ELISA). In contrast, when the teichoic acid structure was altered by replacing choline in the growth medium with structural analogs, the quantity of capsular polysaccharide as measured by a capture ELISA was decreased, demonstrating a linkage in the expression of the two surface carbohydrate structures. A standardized assay was used to assess the relative contribution of cell surface carbohydrates to opsonophagocytosis. The opaque variants required 1.2- to 30-fold more immune human serum to achieve 50% opsonophagocytic killing than did related transparent variants (types 6B and 9V). The opsonophagocytic titer was proportional to the quantity of capsular polysaccharide rather than teichoic acid. The major factor in binding of the opsonin, C-reactive protein (CRP), was also the amount of capsular polysaccharide rather than the teichoic acid ligand. Only for the transparent variant (type 6B), which bound more CRP, was there enhanced opsonophagocytic killing in the presence of this serum protein. Increased expression of capsular polysaccharide, therefore, appeared to be the major factor in the decreased opsonophagocytic killing of opaque pneumococci.

Animals↗
PubMed1999

Population study of HUMTH01, HUMVWA31/A, HUMF13A1, and HUMFES/FPS systems in Azores.

The tetrameric short tandem repeat polymorphisms HUMTH01, HUMVWA31/A, HUMF13A1, and HUMFES/FPS were studied in blood stains obtained from a population of unrelated individuals from the Azores Archipelago (Portugal). Gene frequencies were determined and no deviation from the Hardy-Weinberg equilibrium was found. However, the allelic independence test between loci showed linkage disequilibrium between HUMVWA31/A and HUMFES/FPS. A combined discrimination power and chance of exclusion of, respectively, 0.9999 and 0.9534, reveal the high forensic interest of the four systems. No differences with other caucasoid populations were found, but comparison with some asiatic, eskimo, and amerindian populations showed significant statistical differences.

Amino Acid Sequence↗
PubMed1999

High Prevalence of Hepatitis C Virus Infection in Chronic Hemodialysis Patients.

Hepatitis C virus (HCV) infection is very common among hemodialysis (HD) patients. Transmission of infection in this setting has been related to the number of blood transfusions, the duration of hemodialysis and to nosocomial transmission of virus in the dialysis unit. We conducted a study of 74 HD patients to determine the frequency of HCV at a single point in time (cross-sectional analysis), and to evaluate the association between HCV infection and patients' demographic, clinical and biochemical features. Serum samples were tested for anti-HCV antibodies using a third-generation enzyme-linked immunosorbent assay (ELISA). In the case of a positive result, third-generation recombinant immunoblot and HCV RNA detection by polymerase chain reaction (PCR) tests were performed. Collected data included the patient's age, gender, time on HD, number of blood transfusions and serum alanine aminotransferase (ALT) activity. Twenty-nine patients (29/74.4%) were found to be HCV positive using a third-generation ELISA assay. Of these 29 patients, 27 were also positive by recombinant immunoblot assay and 2 patients had indeterminate results. In the anti-HCV ELISA-positive subgroup, 20 (69%) of the 29 patients had detectable HCV RNA. The HCV RNA-positive patients had received more blood transfusions (15&plusm;3 vs. 5&plusm;1 units of packed red blood cells, p<0.0001) and had been on HD for a longer period of time than the HCV RNA-negative patients (65&plusm;32 vs. 32&plusm;29 months, p<0.0001). Mean serum ALT levels were significantly higher in the HCV RNA positive group (30&plusm;18 vs. 15&plusm;9, p<0.0001). We were unable to determine the most likely mode of transmission in our unit, but these results emphasize the need for strict adherence to blood collecting and handling precautions, careful attention to hygiene in the dialysis units, and sterilization of dialysis machines in order to properly combat this frequent infection.

Journal Article↗
PubMed1998

CCU patient survey tool: all-out recovery.

Studies show that patients' recall of their CCU stays is extremely limited due to various factors. To monitor patient satisfaction in this area, a team of CCU managers developed a survey and began an "All-Out Recovery Program."

Coronary Care Units↗
PubMed1998

Effect of the British warning on contraceptive use in the General Medical Service in Ireland.

In October 1995 the UK Committee of Safety of Medicine (CSM) issued a warning about the safety (thromboembolic disease) of the third generation oral contraceptive steroids (OCS) recommending a switch to older agents except where women were intolerant of first and second generation OCS. Advice by the Irish regulatory authority (Irish Medicines Board) did not recommend such a switch. This pill scare lead to some UK users stopping OCS mid-cycle and a rise subsequently in abortions and pregnancies was noted. To determine whether local or UK advice was followed we obtained data from the General Medical Service (GMS) Scheme on the use of contraceptive steroids prescribed before and after the CSM's warning. The results show a clear shift from usage of the third generation OCS to the second generation OCS and norgestimate-containing OCS. We have also noted a marked fall in the overall use of the combined OCS, a trend that was noted in the U.K. It is clear that prescribers and pill users were influenced more by advice from the UK than by Irish regulatory authority. There is now a centralised European mechanism to licence drugs in the European Union (EU). We need to develop an EU perspective to issues of drug safety, as constituent nations are no longer isolated islands.

Adolescent↗
PubMed1998

Significance of vessel count and vascular endothelial growth factor in human esophageal carcinomas.

The purpose of this study was to determine the angiogenic profile of human esophageal carcinomas. The expression of vascular endothelial growth factor (VEGF) was examined in 6 esophageal carcinoma cell lines and 119 human esophageal carcinoma tissues by Northern blot analysis and immunohistochemistry, respectively. Immunohistochemistry using antibodies against CD34 (endothelial cell specific) was carried out on archival specimens, and microvessels were quantitated by counting vessels in a x200 field in the most vascular area of the tumor. All of the cell lines constitutively expressed VEGF mRNA at various levels. A total of 71 of 119 (59.7%) tumors showed intense VEGF immunoreactivity in the cytoplasm of cancer cells. Vessel count was significantly higher in the VEGF-positive tumors than it was in the VEGF-negative tumors. VEGF expression correlated with the depth of tumor invasion, tumor stage, venous invasion, and lymphatic invasion. The survival rate of patients with high vessel density in the tumor was significantly worse than that of patients with low vessel density in the tumor. There was a tendency for poorer prognosis in the group with VEGF-positive tumors compared with that of the group with VEGF-negative tumors. Overall, these results suggest that VEGF is associated with tumor progression by stimulating angiogenesis in human esophageal carcinoma.

Blotting, Northern↗
PubMed1997

Increased nuchal translucency thickness at 10-14 weeks of gestation as a predictor of severe twin-to-twin transfusion syndrome.

The study examines a possible association between increased nuchal translucency thickness at 10-14 weeks of gestation in monochorionic twin pregnancies and the subsequent development of severe twin-to-twin transfusion syndrome (TTS). In 132 monochorionic twin pregnancies, including 16 that developed severe TTS at 15-22 weeks of gestation and 116 that did not develop TTS, crown-rump length, nuchal translucency thickness and fetal heart rate were measured at 10-14 weeks. In those that developed severe TTS, the prevalence of nuchal translucency thickness above the 95th centile of the normal range and the intertwin difference in nuchal translucency thickness and fetal heart rate were significantly higher than in the non-TTS group; there were no significant differences between the groups in the inter-twin difference in crown-rump length. For fetal nuchal translucency above the 95th centile, the positive and negative predictive values for the development of TTS were 38% and 91%, respectively; the likelihood ratios of nuchal translucency above or below the 95th centile for the development of severe TTS were 4.4 (1.8-9.7) and 0.7 (0.4-0.9), respectively. These findings demonstrate that the underlying hemodynamic changes associated with TTS may manifest as increased fetal nuchal translucency thickness at 10-14 weeks of gestation.

Adult↗
PubMed1997

Fetal heart rate at 10 to 14 weeks and birthweight.

In 6644 singleton pregnancies resulting in live births, the fetal heart rate was measured at 10 to 14 weeks of gestation (median 12). There was no significant association between fetal heart rate and birthweight. These findings demonstrate that if there is an association between fetal heart rate, birthweight and subsequent development of cardiovascular disease the responsible intrauterine insult and/or the adaptive fetal response are not present at 10 to 14 weeks of gestation.

Birth Weight↗
PubMed1997

Telemedicine for airline passengers, seafarers and islanders.

Airline passengers, seafarers and islanders are three different examples of people who can benefit from telemedicine. However, the peculiar characteristics of each group require different applications. In 60 years of activity, the CIRM has assisted more than 37,000 patients. In the 10 years from 1986 to 1996 the Centre provided radio medical assistance to 7647 patients, of whom 6981 (91.3%) were sailors, 642 (8.4%) were people living in isolated areas (small italian islands) with few medical facilities, while only 24 patients (0.3%) were airline passengers. In the same period, the telecommunication service received or transmitted almost 80,000 medical messages.

Aircraft↗
PubMed1997

Prospective Evaluation of In Vitro Production of HIV-1 Specific Antibodies (IVAP), p24 Antigenemia and Viral Culture for the Diagnosis of HIV Infection in Children Born to HIV-1 Infected Mothers.

Three methods (IVAP, p24 antigenemia and viral cultivation) for the diagnosis of HIV-1 infection among children born to HIV-1 infected mothers were prospectively evaluated to determine the applicability of IVAP as a useful technique for that purpose. We tested 15 children (8 p0 and 7 pII) and 19 adults with well-established serological status for HIV infection. The children were followed for at least 1 year, unless tbey developed symptoms of clinical AIDS, or their HIV serology became negative. The IMP method was more sensitive and specific than the other 2 tests in determining whether or not the infants were infected with HIV. All negative test results (5/8) were confirmed during the follow-up period, while two-thirds of the IVAP positive children developed AIDS during the same time period. Despite the small sample studied, we conclude that IVAP is an inexpensive and simple technique potentially useful to establish whether or not HIV-seropositive children born to infected mothers are HIV infected.

Journal Article↗
PubMed1997

[A clinical case of restrictive myocarditis due to senile-type amyloidosis].

We describe the case of a patient with restrictive cardiomyopathy due to primary amyloidosis associated with aging. The patient had a complex myocardial function. A brief review is made of the etiology, diagnostic procedures and therapy of this clinical entity, which is an important rare cause of cardiac death in elderly patients.

Aged↗
PubMed1996

Post-abortion complications after interruption of pregnancy with misoprostol.

The high incidence of abortion in Brazil and the increased use of misoprostol among women having clandestine/unsafe abortions has led to an interest in evaluating whether there is an association between the use of misoprostol and the incidence of septic complications post-abortion. To test this association, a retrospective cohort study was conducted with 1840 women treated post-abortion at the Instituto Materno-Infantil de Pernambuco (IMIP) between 1988 and 1992. Incidence of infection (4.2%) was lower in women stating they had used misoprostol than in those stating that the abortion was not induced (7.9%) and twelve times lower than in women stating that they had used other methods (49.4%). These results suggest that misoprostol is a safe, inexpensive method for inducing abortion, and leads to fewer complications and consequently shorter hospital stays. Misoprostol should be considered a viable option in situations where induction of abortion is legal or medically indicated.

Abortion, Induced↗