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Biomedical subjects

A Carvalho

Publications and source records attributed to A Carvalho.

70 records · Page 4Linked to original sources
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The lupus anticoagulant.

The clinical and laboratory experience with the lupus anticoagulant was reviewed in 37 patients. The anti-coagulant is thought to act by blocking the activation of prothrombin by the prothrombin activator comlex of factors Xa, V, and phospholipid. Although the anticoagulant has been principally associated with diseases of immune origin, 14 of the present patients had disorders not thought to be immune in nature. Eighteen patients underwent twenty-one operative procedures with only a single episode of excessive bleeding. In the author's experience, the lupus anticoagulant is a rare cause of bleeding.

Blood Coagulation↗
PubMedDate not supplied

The Ito "Flow-Through" Centrifuge. A new device for long-term (24 hours) plasmapheresis without platelet deterioration.

An efficacious procedure for continuous plasmapheresis in long-term extracorporeal circulation has not yet been devleoped. This technique could be important in plasma exchange or cross-exchange and in artificial organ support if it could be accomplished safely using heparin as the anticoagulant. When sheep were connected to the Celltrifuge for 23 hours and administered 150 units/kg per hour heparin anticoagulant, we found gross platelet clumping in separated plasma and a 60 per cent fall in platelet count. When 120,000 units of heparin were directly injected into the centrifuge bowl at the onset of the centrifugation followed by hourly heparin administration at 500 units/kg, there was no platelet clumping but the platelet count fell to 52 per cent. Under identical conditions the Ito Flow-Through Centrifuge, a new continuous flow centrifuge with no rotating seals, was used. We found no platelet aggregates and no drop in platelet count, and there was a 100 per cent recovery of platelets in the separated plasma. Platelets sampled from arterial blood and separated plasma were found to have normal function in vitro, and responded 100 per cent to both collagen and ADP. These results indicate that the Ito Flow-Through Centrifuge can be used in plasmapheresis with heparin anticoagulation with no donor platelet loss and normal function in separated plasma.

Animals↗
PubMedDate not supplied

Activity of natural killer cells during HIV-1 infection in Brazilian patients.

UNLABELLED: Natural killer cells are increasingly being considered an important component of innate resistance to viruses, but their role in HIV infection is controversial. Some investigators have found that natural killer cells do not confer a protective effect during the progression of HIV disease, whereas others have shown that natural killer cells may be protective and retard the progression of the disease, either through their lytic activity or by a chemokine-related suppression of HIV replication. In this study, we analyzed functional alterations in the activity of natural killer cells during HIV-1 infection using a natural killer cells activity assay with K562 cells as targets. RESULTS: Our results show that the activity of natural killer cells decreases only in the advanced phase of HIV infection and when high (40:1) effector cell-target cell ratios were used. The depression at this stage of the disease may be related to increased levels of some viral factors, such as gp120 or gag, that interfere with the binding capacity of natural killer cells, or to the decreased production of natural killer cells -activity-stimulating cytokines, such as IFN-a and IL-12, by monocytes, a subset of cells that are also affected in the late stage of HIV infection. The data suggest that decreased natural killer cells cell activity may contribute to the severe impairment of the immune system of patients in the late stages of HIV infection.

Adult↗
PubMedDate not supplied

[Inflammatory mediators, cell counts in nasal lavage and computed tomography of the paranasal sinuses in atopic children]

OBJECTIVE: The aims of this study were to evaluate inflammatory cells, the profile of inflammatory mediators in nasal lavage (NL), and the involvement of the paranasal mucosa in atopic infants with no symptoms of sinusitis. METHODS: 48 atopic patients with allergic rhinitis (AR), and 33/48 patients with asthma were studied; the control group consisted of 13 nonatopic children. Those individuals with acute, chronic or recurrent sinusitis were excluded. The involvement of the paranasal mucosa was assessed by coronal computed tomography (CT) and graded by a standard protocol (0-30). A CT score greater than or equal to 12 indicated extensive involvement. Nasal lavage was used to quantify total and differential nasal cell counts. An aliquot of the supernatant was used for determining inflammatory mediators: interleukin-8 (IL-8), myeloperoxidase (MPO), and eosinophil cationic protein (ECP). Albumin was used as a marker for increased vascular permeability. These measurements were performed on all of the atopic patients and in 6/13 patients in the control group. The three groups were submitted to spirometry and complete blood cell count. RESULTS: Extensive involvement of the paranasal mucosa was observed in 7/33 (21%) of asthmatic patients (Group I) and 2/15 (13%) of those with allergic rhinitis (Group II). The highest CT score in the control group (Group III) was 7. Total cell and eosinophil count/ml and albumin concentration in nasal fluid were higher in asthmatic patients whose CT score was greater than 12. Interleukin-8 concentration, number of neutrophils and epithelial cells/ml in nasal fluid were similar in the three groups. A positive correlation between CT score, peripheral blood eosinophilia, number of eosinophils/ml and eosinophil cationic protein concentration was found in the nasal fluid of atopic children (n=48). There was an association between number of neutrophils and titers of interleukin-8 and myeloperoxidase, and between interleukin-8 and eosinophil count. CONCLUSIONS: in asthmatic patients with no symptoms of sinusitis, the extensive involvement of the paranasal mucosa is associated with blood and nasal lavage eosinophilia and cellular activation. Neutrophil infiltration and activation were not related to increased involvement of the paranasal mucosa.

Journal Article↗
PubMedDate not supplied

[Prevalence of markers of hepatitis B infection in the adult population of the district of Coimbra].

AIM: To assess the prevalence of hepatitis B markers in the adult population of the Coimbra district, in the central region of Portugal. METHODS: The study included 657 subjects chosen aleatorily from 4 characteristic councils of the Coimbra district. They were questioned regarding risk factors and blood samples were taken for HBsAg, anti-HBs and anti-HBc testing. Anti-HCV was previously determined and it was positive in 0.45% of the cases. RESULTS: HBsAg was found in 0.91%. Anti-HBs and anti-HBc were both positive in 6.08%, anti-HBc without anti-HBs was found in 1.82% and anti-HBs without anti-HBc was found in 1.67% (11 cases, 8 vaccinated). The general prevalence of hepatitis B markers was 9.3%. Higher prevalences were found in the subjects over 50 years of age, 13.5% (p < 0.05), and in the urban area, 13.2% (p < 0.05). CONCLUSIONS: 1. The HBsAg prevalence in our region is 0.9%; 2. The general prevalence of hepatitis B markers is 9.3%; 3. HBsAg prevalence is higher than anti-HCV prevalence calculated in the same sample; 4. The prevalence of hepatitis B markers in our region is lower than in other Southern European countries.

Adult↗
PubMedDate not supplied

[Human alfa-2b in rabbit's eyes].

The toxicity of human interferon alpha 2b in rabbit's vitreous and conjonctiva is studied through electroretinography, echography, angiography and histological examination. Interferon was injected in increasing doses 150,000 UI, 500,000 UI and 1,000,000 UI. The results from examinations in the rabbits are presented and the conclusion is drawn, that good tolerance is achieved, even at higher doses.

Animals↗
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Plasma heparin neutralizing activity in patients with valvular stenosis and prosthetic heart valves.

Patients with mitral and aortic valvular stenosis had plasma heparin neutralizing activity (HNA) which were comparable to the control group. In contrast, plasma HNA was elevated in patients with prosthetic valves, particularly in the group with prosthetic aortic valves. Neither the type nor the size of the valve appeared to influence the HNA level. No correlation was evident between plasma HNA levels and a history of systemic arterial embolism. It remains to be determined whether elevated plasma HNA levels result from platelet aggregation on the valve surface, or from platelet lysis due to turbulence around the prosthetic valve.

Aortic Valve↗
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[Percutaneous transluminal angioplasty. An efficient alternative in the treatment of peripheral obstructive arteriopathy].

At the present, patients with obstructive vascular disease in the lower extremities can be treated with percutaneous procedures without surgery. By what is called Interventional Radiology. Three patients with iliac or femoral arterial obstructions were treated with Percutaneous Transluminal Angioplasty (PTA). For all of them, claudication was the principal symptom and was treated with PTA due the failure of regular treatment. The dilatation was performed with high pressure balloon. Both technical and clinical results showed success and there were no complications.

Aged↗
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[Inter-hospital transfer in pediatrics].

We present the results of a prospective study of the technical and human characteristics of the transport of children transferred from other Hospitals to our PICU. During eight months of 1994, 153 children were transferred and 138 included in our study. Their ages varied between one month and fourteen years and the majority (60%) were males. 67% of the patients transferred required Pediatric specialties and 30% required surgical specialties. Accidents were the most common pathology (40%), followed by neurologic, respiratory and infectious situations (15% each) The most frequently used means of transport was an ambulance, in 88% of the cases. Only 12% of these were medically equipped and 10% had CPR material available. In 23% of the transports the patient was accompanied by both a nurse and a medical doctor. In 25% by a nurse only and in 14% by a medical doctor. None of them had training in transport medicine. The length of the transport varied between 30 min. and 14 h, with a mean of 2h. Ten patients had major complications during transfer. Their CCS on arrival at the PICU was > or = 3 in 55% of the cases. Based on these results we discuss the obvious need for a Pediatric Transport System in our country.

Adolescent↗
PubMedDate not supplied

[Individualized monitoring of the therapy with gentamycin using pharmacokinetic methods. Which method to choose?].

Gentamicin has an excellent cost/efficacy ratio for gram negative infections treatment. Its use is often limited in clinical practice by its narrow safety margins and a high incidence of toxicity. Gentamicin related nephrotoxicity is a major adverse effect, mostly in patients with other concomitant potential risk factors. As many other Authors we have found in our Internal Medicine Service during 1992 a gentamicin related nephrotoxicity incidence of 22.5%. Various empiric methods and nomograms have shown a significant incidence of error in predicting individualized gentamicin dosage regimens. Pharmacokinetics methods have demonstrated much better results regarding efficacy and toxicity. The aim of this prospective study carried out during 1993-1994 was to individualize by pharmacokinetics methods dosage regimens of gentamicin in patients with one or more concomitant risk factors of nephrotoxicity. The purpose of pharmacokinetics dosage regimens has been to achieve trough serum concentrations of gentamicin in therapeutics range-0.5 to 2 micrograms/ml-on the first 24 to 48 hours of treatment, and the maintenance in this range during all the treatment, avoiding both toxic and under therapeutic levels. The incidence of gentamicin related nephrotoxicity has been evaluated in this population. Twenty patients were studied: 18 males and 2 females aged 59.6 years (19 to 85). All had one or more potential risk factors for nephrotoxicity-65 years or more: 13, previous renal failure: 6, other nephrotoxic drugs: 10, diuretics: 4, dehydration: 5, congestive heart failure: 5, diabetes: 3, hypertension: 3. For the first 10 patients gentamicin dosage regimens have been determined by Sawchuk-Zaske pharmacokinetics method and for the subsequent 10 patients by Bayesian method. The two subpopulations had no significant differences regarding mean age, sex and potential risk factors for nephrotoxicity. Results of Sawchuk-Zaske method: 53 trough gentamicin serum concentration were obtained; 86.8% were within the therapeutic range, 7.5% were toxic and 5.7% were under therapeutic. Results of Bayesian method: 44 determinations of gentamicin through concentrations were obtained; 86.3% within therapeutic range, 2.4% were toxic and 11.3% were under therapeutic. A great variability in pharmacokinetic patient's profile has been found and explains the great variability of individualized dosage regimens of gentamicin (30 to 320 mg/day). No patients had gentamicin related nephrotoxicity. Both pharmacokinetics methods lead to a efficient and save employment of gentamicin in patients with previous renal failure and other potential risk factors for nephrotoxicity.

Adult↗
PubMedDate not supplied

[Nosocomial infection in a pediatric intensive care unit].

UNLABELLED: Patients in intensive care units (ICU) are 3 to 4 times more prone to nosocomial infection (NI) than patients in general wards owing to the severity of their pathology and the frequent use of invasive procedures. The aim of this study was to establish the incidence of NI in an ICU and the associated risk factors. PATIENTS AND METHODS: During 18 months, all patients with severity scores III and IV (Clinical Classification System) were studied, (n = 575). The admissions were mainly due to accidents (24.7%), neurological (19.1%), surgical (17.2%), respiratory (11.1%) and infectious (7.0%) disease. The mean duration of stay was 2.4 days. The mortality was 5.2%. The evaluation protocol of these patients included determination of the PRISM score, registration of every invasive procedure and daily search for clinical and laboratory signs of infection. NI was defined according to the criteria of the Centers for Disease Control. Both the intrinsic and extrinsic risk factors were analysed and in the statistical analysis the null hypothesis was rejected at the significance level of p < 0.05. RESULTS: The incidence of NI was 7.6%. The infections occurred in the respiratory tract in 20 patients, bloodstream in 8, genito-urinary tract in 2, central nervous system in 2, skin in 2, gastrointestinal tract in 2, eyes in 1 and surgical wound in 1. There were isolates in 60.6%. The mean duration of stay was longer in patients with NI (9.8 versus 1.9). The factors most closely associated with NI were higher PRISM scores, malnutrition, immunodeficiency failure of 2 or more organs, administration of antibiotic since admission or corticosteroids and simultaneous use of 3 or more invasive procedures. The risk of pneumonia was significantly increased in patients with mechanical ventilation and all the patients with bacteremia had central venous catheters. The mortality was higher in the group with NI (18.2%) than in the group without NI (4.4%). CONCLUSIONS: The incidence of NI is acceptable in our ICU. The most frequent location was the respiratory tract (52.6%). The pathogens most frequently isolated in this ICU were Gram negative rods. The risk of NI increased in more debilitated patients with more severe disease who were administered antibiotic or corticosteroids and submitted to more invasive procedures.

Adolescent↗