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Biomedical subjects

G Acocella

Publications and source records attributed to G Acocella.

18 recordsLinked to original sources

Tuberculosis and HIV infection association in a rural district of northern Uganda: epidemiological and clinical considerations.

59 (18.3%) of 323 patients with tuberculosis (TB) tested for HIV-1 antibody by ELISA technique (Wellcozyme) were seropositive. In the control group selected among the health personnel working in the Arua Hospital, 7.7% were found positive for HIV-1 antibody, thus showing a significantly lower prevalence compared with the TB patients (P < 0.005). The prevalence of HIV infection was 50% in the urban TB patients, 7% in TB patients living in rural areas surrounding Arua town and 1.6% in the peripheral rural setting. Of 27 TB patients with clinical AIDS, 18 died during the course of the study. The AIDS patients' survival rate was 46.4% 6 months after diagnosis, and 21.4% after 16 months, the median period of survival being 5.0 months. Risk factors, sputum conversion rate, clinical and radiological findings were analysed. No significant difference was found between seropositive and seronegative TB patients for clinical drug-related toxicity (P > 0.05).

Adolescent

Proposal of an improved score method for the diagnosis of pulmonary tuberculosis in childhood in developing countries.

210 children aged less than 5 years, referred to the Arua Regional TB Centre (Uganda) for suspected pulmonary tuberculosis (PTB), were examined by anamnesis, clinical examination, Mantoux test, gastric washing, chest X-ray. The response to treatment criterion was applied to the patients treated. According to the score method suggested by Ghidey and Habte, 31 children were diagnosed as PTB patients. 30 of the 31 children with PTB tested positive for alcohol acid-fast bacilli (AAFB) in the aspirated juice. The Mantoux test and X-rays gave a minor contribution to diagnosis. The clinical results are commented. A statistical analysis was carried out to evaluate the role of gastric washing in the diagnosis of PTB in children under 5 years of age (sensitivity, 96.8%; specificity, 92.2%; positive predictive value, 68.2%; negative predictive value, 99.4%). The response to treatment was also evaluated. A modified enlarged score method (based on gastric washing and including response to treatment) is proposed to be applied in developing countries where chest X-ray and other facilities are often lacking.

Antitubercular Agents

Comparison of three different regimens in the treatment of acute brucellosis: a multicenter multinational study.

The present study was undertaken to evaluate efficacy, safety and patient acceptability of three antibiotic regimens for the treatment of acute brucellosis. Six different centres were involved: three in France, one in Greece and two in Spain. The regimens were: oral rifampicin 900 mg/day plus oral doxycycline 200 mg/day for 45 days (A), oral doxycycline 200 mg/day for 45 days plus im streptomycin 1 g/day for 21 days (regimen B) [corrected] and the WHO regimen (C) combining oral tetracycline 2 g/day for 21 days plus im streptomycin, 1 g/day, for 14 days. Regimens A and B were randomly allocated in all centres, while regimen C was allocated only in two centres. All patients were suffering from acute brucellosis clinically and biologically proven. 143 patients were allocated for treatment and analysed. Their mean age was 41 years (range 13-70), 49 were female and 94 male, and their mean weight was 64 kg (range 35-98). Among these patients, 14% had localized disease (nine orchitis, eight osteo-articular involvement and one pleural effusion), but there was no statistical difference between the three regimens in regard to this localized disease. Forty-five per cent of the patients had positive blood cultures. The cure rate with regimen A was 95%, 96% with regimen B and 59% with regimen C. Thus regimen A presented the same efficacy rate as regimen B, but regimen C cannot be regarded as the treatment of choice for acute brucellosis.

Acute Disease

Comparative bioavailability of isoniazid, rifampin, and pyrazinamide administered in free combination and in a fixed triple formulation designed for daily use in antituberculosis chemotherapy. I. Single-dose study.

A comparative bioavailability study of the antituberculosis drugs isoniazid, rifampin, and pyrazinamide was carried out in a group of 10 healthy volunteers after administration of the three compounds, once in individual association and once in a combined, fixed preparation. The investigation was designed as an open, crossover study where each subject received five tablets of a preparation containing 50 mg isoniazid, 120 mg rifampin, and 300 mg pyrazinamide (corresponding to a total dose of 250 mg isoniazid, 600 mg rifampin, and 1,500 mg pyrazinamide). The same doses were administered in the session where the drugs were combined using the individual formulations. For each subject and experimental session, 15 blood samples were collected over a period of 24 h, and the plasma concentrations of the three drugs were assessed. The results indicated the absence of negative pharmacokinetic interactions between the drugs when administered in both free and this new, fixed combination.

Adult

Comparative bioavailability of isoniazid, rifampin, and pyrazinamide administered in free combination and in a fixed triple formulation designed for daily use in antituberculosis chemotherapy. II. Two-month, daily administration study.

The time course of the plasma concentrations of isoniazid, rifampin, and pyrazinamide was assessed in a group of 13 patients with lung tuberculosis treated over a period of 2 months on a continuous daily basis with a fixed triple combination of the same drugs. The blood kinetics of the three antituberculosis drugs were determined on Days 1, 15, 30, and 60 of treatment. The triple combination employed in this study contained 50 mg isoniazid, 120 mg rifampin, and 300 mg pyrazinamide per tablet, the number of tablets ranging from four to seven per day according to the body weight of the patients. Almost superimposable plasma concentration curves for isoniazid were observed during the 4 days of the study. For rifampin, a fall in the plasma concentrations at the time intervals after the peak was observed comparing the data on Day 1 with those on Days 15, 30, and 60, which did not differ from each other. This finding is thought to be due to the well-known phenomenon of self-induction, which leads to an increased rate of disposal of the antibiotic from the blood compartment within the first and second weeks of continuous treatment. For pyrazinamide, an equilibrium in the opposite sense as that of rifampin seemed to take place within the 2 months of the study. Because of the relatively high plasma levels observed 24 h after each administration, an increase in plasma concentrations with respect to those observed on Day 1 was found on Days 15, 30, and 60, the levels on these days no differing from each other.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Can rifampicin use be safely extended? Evidence for non-emergence of resistant strains of Mycobacterium tuberculosis.

Data on the incidence of primary resistance to rifampicin in Mycobacterium tuberculosis strains have been collected from various countries. Strains isolated from those countries where rifampicin is used for both tuberculous and non-tuberculous conditions (Italy, Argentina, Brazil, and Spain) did not show a higher incidence of primary resistance than did strains from other countries (France, U.K., and U.S.A.) where rifampicin use is confined to tuberculosis. It is concluded that there is no evidence to justify fears of an increased incidence of resistance to rifampicin in M. tuberculosis if rifampicin were used discreetly for treating non-tuberculous infections.

Antitubercular Agents

Serum and urine concentrations of rifampicin administered by intravenous infusion in man.

Two studies were carried out in man with the aim of assessing the serum and urine concentrations of rifampicin administered by i.v. infusion. In patients suffering from various diseases, a dose of 600 mg i.v. proved to be equieffective with a 600 mg oral dose. Repeated administration of a 600 mg dose by i.v. infusion for a week produced serum levels corresponding to those achieved by oral administration. With the i.v. preparation the drop in serum rifampicin levels during continuous administration was less marked than with the oral administration. The recovery of antibiotic in the urine seems to be lower with i.v. than with the oral preparation. The i.v. preparation was very well tolerated by all the patients.

Administration, Oral

Clinical pharmacokinetics of rifampicin.

After oral administration on an empty stomach, the absorption of rifampicin (rifampin) is rapid and practically complete. With a single 600mg dose, peak serum concentration of the order of 10microgram/ml generally occur 2 hours after administration. The half-life of rifampicin for this dose level is of the order of 2.5 hours. The amount of rifampicin extracted by the liver during its first passage through the hepatoportal system and transferred to bile is relevance for the time course of distribution of the antibiotic in the blood compartment. With dose of the order of 300 to 450mg, the excretory capacity of the liver for the antibiotic is saturated. As a consequence, increasing the dose of antibiotic results in a more than proportional increase in serum concentrations. On repeated administration, and most likely as a consequence of self-induced (autoinduction) metabolism, the rate of disappearance of rifampicin from the blood compartment increases in the early phase of treatment, the phenomenon affecting mainly the levels following the peak, with a consequent reduction in half-life. Approximately 80% of rifampicin is transported in blood bound to plasma proteins, mainly albumin. Rifampicin is well distributed, although to a different degree, in the various tissues of the human body. Probably in the hepatocyte, rifampicin undergoes a process of desacetylation. The metabolic derivative, desacetylrifampicin, is more polar than the parent compound, and microbiologically active. This metabolite accounts for the majority of the antibacterial activity in the bile Rifampicin is almost equally excreted in the bile and urine, the recovery in the 2 fluids being of the same order of magnitude. Administration of rifampicin to newborn infants and children is followed by blood levels generally lower than those found in adults for the same dose levels. In patients with impaired liver and kidney function the elimination of the antibiotic from the blood compartment is slower than in normal subjects. Rifampicin has been found to compete with bilirubin and other cholefil substances for biliary excretion, giving rise to transient and reversible increased bilirubin and BSP retention values. A kinetic model study on the transfer constants between various body compartments has indicated that rifampicin is rapidly absorbed from the intestine and that the absorption rate increases with time. Rifampicin as such is transferred into urine at a rate 3 times higher than the rate of transfer into bile. Desacetylrifampicin, the more polar metabolic derivative of rifampicin, behaves in the opposite way since its rate of transfer into bile is 4 times higher than that into urine. The rate of biotransformation of rifampicin into desacetylrifampicin is of the same order of magnitude as than of biotransformation of the latter into a further metabolic derivative, which could be a glucuronide conjugate...

Anticoagulants

Eskimo: an epidemiological simulation kinetic model for tuberculosis.

A simple, easy to use, kinetic model allowing the simulation of the main epidemiological parameters of tuberculosis and of the financial costs associated with the implementation of different anti-tuberculous policies, has been developed and described. The model, which has been denominated "ESKIMO" (Epidemiological Simulation Kinetic Model) can be utilized on a personal computer and requires, for its use, the knowledge of a series of easily available census data relative to a given country or geographical area, an essential epidemiological profile of the disease in the same area and data which characterize one or more antituberculous treatments in therapeutic and financial terms. The rationale of the model, which is a multicompartemental system, derive from an analysis of the relationships (transfer rates) between sub-populations of individuals in relation to tuberculosis either when the dynamic state of the system is governed by "natural forces" (no treatment) or when an external action is applied to it with an aim to alter its internal pathways in a favourable sense (vaccination, long-term hospitalization, chemotherapy). The model is based on the assumption that the main objective of any antituberculous program is the reduction in size of the subpopulation of patients who can infect other individuals and therefore perpetuate the disease. Validation and projection tests carried out through Eskimo seem to indicate that concentrating the analysis on the effect of various treatments on this group of patients simplifies the calculations while the relative precision of the estimates of other parameters is very satisfactory. The results of several simulations substantiate and quantify the opinions expressed by several experts in the past that the policy of applying cheap regimens of low efficacy to a relatively small fraction of the patients' population, as frequently done in developing countries, not only does not alter the trend of the disease but produces essentially negative results (increase in the number of new cases and in the frequency of resistant M. tuberculosis). Treatment with highly effective regimens of the same number of patients as those treated now (constant coverage) and therefore without the extra costs resulting from the improvement of the available sanitary infrastructures, produces much better results in clinical terms and overall saving of financial resources.

Computer Simulation

Past, present and future trends in tuberculosis epidemiology in a region of northern Italy. An analysis carried out through the application of a simulation model (Eskimo).

The epidemiological model Eskimo has been utilized to simulate some epidemiological parameters relative to tuberculosis in a restricted geographical area of northern Italy. After having identified a series of features relative to the regimens applied in the area in the period 1982-86 and which were found to be compatible with the observed data, this hypothesis has been utilized to project data on tuberculosis for the period 1986-1996. The results have indicated that the incidence in the area should stabilize around values of 20 new cases per year (per 100,000 population). A decrease in the incidence can be expected to occur only if the regimens so far employed are brought to a greater part of the patients' population (increasing coverage). The effects of importing the disease from developing countries through immigration and of the AIDS epidemic are likely to negatively affect the trend of tuberculosis incidence in the future.

Cohort Studies