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Biomedical subjects

B Dimitrova

Publications and source records attributed to B Dimitrova.

15 recordsLinked to original sources
PubMed2006

Health service providers' perceptions of barriers to tuberculosis care in Russia.

The Russian Federation has witnessed a marked rise in rates of tuberculosis (TB) over the past decade. Public health TB control institutions remain broadly modelled along pre-1990 lines despite substantial programmes of investment and advocacy in implementing the World Health Organization's 'Directly Observed Treatment--short course' (DOTS) strategy. In 2002, we undertook a qualitative study to explore health care providers' perceptions of existing barriers to access to TB services in Samara Oblast in Russia. Six focus group discussions were conducted with physicians and nurses from facilities in urban and rural areas. Data were analyzed using a framework approach for applied policy research. Barriers to access to care were identified in interconnected areas: barriers associated with the health care system, care process barriers, barriers related to wider contextual issues, and barriers associated with patients' personal characteristics and behaviour. In the health care system, insufficient funding was identified as an underlying problem resulting in a decrease in screening coverage, low salaries, staff shortages, irregularities in drug supplies and outdated infrastructure. Suboptimal collaboration with general health services and social services limits opportunities for care and social support to patients. Worsening socioeconomic conditions were seen both as a cause of TB and a major obstacle to access to care. Behavioural characteristics were identified as an important barrier to effective care and treatment, and health staff favoured compulsory treatment for 'noncompliant' patients and involvement of the police in defaulter tracing. TB was profoundly associated with stigma and this resulted in delays in accessing care and barriers to ensuring treatment success.

Focus Groups↗
PubMed2005

Health system frailties in tuberculosis service provision in Russia: an analysis through the lens of formal nutritional support.

OBJECTIVE: The aim of this study was to describe health system challenges faced by tuberculosis (TB) treatment facilities in Russia through an analysis of formal institutional dietary provisions to patients in an inpatient facility that provides care for poor patients. METHODS: Analysis of formal dietary provisions by institutions and financing data from TB hospitals in Samara Oblast, Russia. RESULTS: Formal dietary provision for inpatients with TB has fallen substantially in recent years. In a hospital providing inpatient care for the poorest patients with fewest social support networks, this has been very pronounced. The likely reason for this is that financial support for other budget lines, principally salaries, has required protection. CONCLUSION: Formal institutional nutritional support in institutions providing care for the poorest patients with TB is unlikely to be enhancing the speed of recovery, or reducing the duration of infectiousness. Furthermore, the role that hospital may have played in the past in enabling patients to regain weight lost before admission may have been limited by reductions in formal financing. Reductions in state provision of food for patients may serve as an important illustration of wider TB control system frailties in the Russian Federation.

Budgets↗
PubMed2005

Increased risk of tuberculosis among health care workers in Samara Oblast, Russia: analysis of notification data.

SETTING: Samara Oblast, Russia. OBJECTIVE: To compare the rates of tuberculosis (TB) in health care workers (HCWs) working in TB services, general health services (GHS) and the general population in a region of the Russian Federation. DESIGN: Analysis of notification rates of TB among HCWs, GHS workers and the general population during the 9-year period from 1994 to 2002. RESULTS: During 1994-2002, TB incidence among staff employed at the TB services in Samara Oblast was ten times higher than among the general population, reaching 741.6/100 000 person years at risk. Staff working at in-patient TB facilities were found to be at highest risk, with an incidence rate ratio of 17.7 (95% CI 11.6-27.0) compared to HCWs at the GHS. CONCLUSIONS: HCWs at TB services in the Russian Federation are at substantially increased risk for TB, suggesting significant risks from nosocomial transmission. Control of institutional spread of TB in the Russian Federation is an area that requires urgent attention, especially given the epidemic of human immunodeficiency virus that Russia is currently witnessing.

Adult↗
PubMed2003

Tuberculosis control in Samara Oblast, Russia: institutional and regulatory environment.

SETTING: Tuberculosis control programme in Samara Oblast, Russia, funded in part by the government of the United Kingdom. OBJECTIVE: To identify and evaluate institutional and regulatory influences as well as incentives and disincentives that might be amenable to change in the promotion of the DOTS strategy. DESIGN: Multidisciplinary situational analysis through in-depth interviews of stakeholders and review of official federal and oblast documents. RESULTS: Interpretation of traditional notification data is complex because classification and reporting systems differ from World Health Organization principles. Regulations governing financing encourage lengthy hospitalisations and interventions, and provide few incentives to shift policy to ambulatory care. CONCLUSION: Accurate comparability of epidemiological trends and programmatic successes requires equivalent classification and reporting systems. If the DOTS strategy is to be sustainable, changes to financing systems will be needed.

Federal Government↗
PubMed2000

Reversed-phase high-performance liquid chromatography for evaluating the distribution of pharmaceutical substances in suppository base-phosphate buffer system.

The aim of this study was to assess the potency of the reversed-phase high-performance liquid chromatography (RP-HPLC) for in vitro evaluation of the distribution behavior of common drugs between one of the generally used suppository bases Witepsol H15 and the rectal liquid which is imitated by a phosphate buffer, pH 7.2. The distribution coefficients (log K) of nine compounds--paracetamol, caffeine, diclofenac, propyphenazone, indomethacin, codeine base, codeine phosphate, phenobarbital acid and phenobarbital sodium salt were determined by the classical shake-flask' method followed by RP-HPLC quantitative assay. The capacity factors log k' of the compounds were determined on reversed-phase C18 column at a number of methanol-5 mM phosphate buffer, pH 7.2 mobile phases containing different percentages of methanol (phiMeOH). The apparent capacity factors log k(w)app were derived by extrapolation of the methanol concentration to zero and using the correction for ionization, the real capacity factors log k'(w) were calculated. The lipophilicity of the compounds was assessed by the partition coefficients CLOGP and the distribution coefficients CLOGD7.2, calculated for the n-octanol-water system. Correlations between log k'(w) and CLOGP, log k(w)app and CLOGD7.2, log k(w)app and log K were found. The last correlation indicated that the parameter log k(w)app was suitable for evaluating the distribution behavior of the studied drugs in the examined Witepsol H15-rectal liquid system. The predictive power of this correlation was tested by a set of nine non-congeners. It was shown that the classical 'shake-flask' method for determination of the distribution behavior of the studied drugs between the suppository base Witepsol H15 and the phosphate buffer, pH 7.2 might be replaced by the RP-HPLC technique due to its priorities of rapid, stable and reproducible experiments.

Buffers↗
PubMed1996

Isocratic reversed-phase liquid chromatography of all-trans-retinoic acid and its major metabolites in new potential supplementary test systems for developmental toxicology.

An isocratic reversed-phase high-performance liquid chromatographic procedure for the determination of all-trans-retinoic acid (all-trans-RA) and its metabolites, all-trans-4-oxo-RA, 5,6-epoxy-RA, 9-cis-RA and 13-cis-RA, in mouse plasma and embryo and in new in vitro potential test systems for developmental toxicology has been developed. These compounds, their biological precursor retinol (vitamin A) and the internal standard were resolved on a Spherisorb ODS-2 (5 microns) column (250 x 4.6 mm I.D.) with acetonitrile-water-methanol-n-butyl alcohol (56:37:4:3, v/v) containing 100 mM ammonium acetate and 70 mM acetic acid as the elution system, with a total run time of 23 min. The assay was linear over a wide range, with a lower limit of quantitation of 50 ng/ml or 10 ng/mg of protein for all-trans-RA, 13-cis-RA and 9-cis-RA and of 25 ng/ml or 5 ng/mg protein for the 4-oxo- and 5,6-epoxy-metabolites. At these concentrations, intra-assay coefficients of variation (C.V.) of the retinoids were 3-9%. Mean intra-assay C.V. averaged 5-7% in the tissues studied. Its use is discussed for RA measurements in some of the new test systems--Drosophila melanogaster, sea urchin embryos and cultured human keratinocytes--that have to be evaluated in toxicological testing, supplementary to standard assays in mammals.

Animals↗
PubMed1995

Determination of the retinobenzoic acid derivative Am580 in rat plasma by high-performance liquid chromatography.

A specific liquid chromatographic method for the determination of 4-[[(5,6,7,8,8-tetrahydro-5,5,8,8-tetramethyl-2- naphthalenyl)carbonyl]amino]benzoic acid (Am580) in rat plasma is described. The procedure includes one-step isolation of the compound and the internal standard (naphthol AS) from protein precipitated with acetonitrile, resolution on a reversed-phase column (Supelcosil LC18-DB, 5 microns) with water-acetonitrile-methanol-n-butanol (45:40:14:1, v/v) containing 65 mM ammonium acetate as elution system and UV absorbance detection at 280 nm. The assay was linear over a wide range (25-5000 ng ml-1) and the limit of quantitation was 25 ng ml-1 using 0.2 ml of plasma. It was precise and reproducible enough for pharmacokinetic studies. Application to a preliminary disposition study in the rat indicated that Am580 was characterized by a relatively large apparent volume of distribution (1.1-1.5 1 kg-1) and small clearance (8.8-9.7 ml min-1 kg-1). Its pharmacokinetic behaviour was linear within the dose range considered (2 and 10 mg kg-1, i.p.).

Acetonitriles↗
PubMed1994

Determination of orally administered all-trans-retinoic acid in human plasma by high-performance liquid chromatography.

All-trans-retinoic acid (RA) is used successfully in the treatment of acute promyelocytic leukaemia (APL), although unexplained relapses occur in many of the patients. Pharmacokinetic studies may help in understanding the mechanism of resistance to RA and a simple and rapid procedure for its determination in biological samples may be advantageous. A high-performance liquid chromatographic procedure is described, involving one-step extraction of RA from plasma, isocratic elution from a reversed-phase column (LiChrosorb RP-18, 5-microns particle size) and UV detection at 340 nm. The calibration graph is linear over a wide range and the limit of detection is approximately 10 ng/ml, using 0.5 ml of human plasma. The method is selective for RA, accurate and robust and thus suitable for the routine analysis of plasma samples from patients undergoing RA therapy. Analysis of plasma in a patient on RA therapy (45 mg/m2 per day) confirmed that during continuous treatment with RA the drug plasma concentrations are markedly lower at the time of relapse than on the first day of treatment.

Administration, Oral↗
PubMed1990

[Pulmonary tumor embolism in primary cancer of the liver].

A case of a 73 years old man with macronodular liver cirrhosis, ascites, jaundice and a primary hepatocellular carcinoma is presented. The patient died suddenly and at the post mortem embolism of the pulmonary artery was found caused by tumor fragments. The tumor had infiltrated the wall and penetrated into the lumen of vena cava inferior.

Aged↗
PubMed1988

Symbolic trepanations of skulls from the Middle Ages (IXth-Xth century) in Bulgaria.

Symbolic trepanations (ST) of skulls (IXth-Xth century) found in north-eastern Bulgaria near the West coast of the Black Sea were Studied. It was established that trepanations were performed on subjects well over the age of thirty and cover 41% from the total material which is the highest frequency documented so far. Tracks of the ST are localized most often on and round the sagittal suture, bregma and lambda. Their number ranges from 1 to 9 per cranium with a diameter of 3-4 to 20-28 mm and a depth of 1 to 6 mm. They are usually round and encircled with a prominent ridge. In this article we try to explain the reasons for the symbolic trepanations as well as the link between the traditions of the ancient Turkish nations and Chinese medicine.

Adult↗
PubMed1987

Investigation of an alkylamine modified and pH-controlled mobile phase for separation of pyrazolone derivatives by high-performance liquid chromatography.

The separation of pyrazolone derivatives with different acid-base properties and polarities has been investigated in view of recent concepts about the retention mechanisms in reversed-phase liquid chromatography. It is shown that both the protonated (BH+) and uncharged (B) bases undergo a dual mechanism of retention due to solvophobic and silanophilic interactions. The latter are easily suppressed by the addition of an alkylamine modifier (dibutylamine) to the mobile phase. An ion-pairing mechanism is found to be valid in the retention of negatively charged (A-) pyrazolone derivatives, since the dibutylamine modifier (BH+) serves as an appropriate counter ion. The behaviour of these solutes can be predicted from the pH dependence of their capacity factors, and a new simple method is proposed for calculating the theoretical sigmoidal curves. It is shown that the elution order of the compounds can be changed by control of both the pH value and the modifier concentration in the mobile phase.

Ampyrone↗