Epidemiology of obesity and hypertension and related risk factors in Uzbekistan

OBJECTIVE

This study examined the prevalence of obesity and hypertension and associated behavioral risk factors in adult men and women in Uzbekistan. The study also examined the association between obesity and hypertension.

METHOD

The analysis used data from the 2002 Uzbekistan Health Examination Survey, which included a nationally representative sample of 2333 men aged 15-59 years and 5463 women aged 15-49 years. The survey measured height, weight and blood pressure and included questions on physical activity, dietary habits, tobacco smoking, alcohol use and other characteristics. The analysis was conducted using binary and multinomial logistic regression methods, separately for men and women.

RESULTS

Eating animal source protein and tobacco smoking in the past were positively associated with obesity, but there were no consistent associations with other dietary indicators, physical activity level or alcohol use. Obese men and women were about three times as likely to suffer from hypertension as those with a normal BMI (odds ratio (OR)=3.01; 95% confidence interval (CI): 1.67-5.44; P<0.001 for men and OR=2.82; 95% CI: 2.05-3.86; P<0.001 for women), independent of physical activity level, dietary habits, tobacco smoking and other factors. For men, the risk of hypertension was strongly positively associated with BMI only at BMI levels above 25 kg/m(2), but for women a positive relationship was observed at all BMI levels.

CONCLUSION

The study found a strong positive association between obesity and hypertension in adult men and women in Uzbekistan. The shape of the relationship between BMI and hypertension is different for women than for men, requiring further research to explore this relationship.

Selective repression of low-density lipoprotein receptor expression by SP600125: coupling of histone H3-Ser10 phosphorylation and Sp1 occupancy

In this study, we show that exposure of human hepatocellular HepG2 cells to SP600125 rapidly and dramatically reduced global histone H3-Ser10 phosphorylation, without significantly affecting the global acetylation of neighboring lysines. The loss of phosphorylation is not due to changes in cell cycle distribution and/or apoptosis and is mediated independent of either p46/54(JNK) or MSK-1/2 inhibition. Moreover, SP600125 repressed the basal expression of the endogenous LDL receptor in a gene-specific manner, whereas the expression of squalene synthase, sterol response element-binding protein-1, and beta-actin was not altered by SP600125. Finally, chromatin immunoprecipitation and in vivo footprinting assays provided direct evidence that localized histone H3-Ser10 dephosphorylation at the low-density lipoprotein receptor promoter was associated with a significant decrease in the occupancy of the Sp1 binding site, with a slight reduction in the occupancy of RNA polymerase II. Together, our findings show that SP600125 is an efficient inhibitor of histone H3-Ser10 phosphorylation in vivo, and our results led us to hypothesize that this modification plays a novel role in regulating transcriptional control by modulating promoter accessibility to maintain basal expression in a gene-specific manner.

Application of in vitro methods for selection of Lactobacillus casei strains as potential probiotics

Probiotics have established their efficacy as dietary adjuncts providing benefits to consumers, but the selection of probiotics before incorporation in diet requires close scrutiny in the form of in vitro as well as in vivo tests. The present study was undertaken to check different in vitro characteristics of seven Lactobacillus casei strains. The characteristics studied include acid and bile tolerance, adhesion and cell surface hydrophobicity, antimicrobial effect on common pathogens and cholesterol reduction. All strains were able to resist pH 3 for 3 h, though resistance to pH 2 was exhibited by NCDC 17, C1 and Y strains only. NCDC 63 and VT strains were able to tolerate 1% and 2% bile concentrations for 12 h. There was wide variation in ability of strains to adhere to isolated rat epithelial cells. The index was highest for C1 at 66%. The electron microscopic adhesion studies on the stainless steel chips did not reveal any specific attachment to surfaces by any of strains. The hydrophobic character for octane was highest for strain C1 at 54.06% and lowest for strain C2 at 4.65%. The ability to antagonize common pathogens was observed in all strains but this activity was attributed to production of organic acids and no specific compound caused the inhibitory effect. The cholesterol reducing ability varied not only for strains but also for time of incubation. NCDC 17 showed maximum reduction in cholesterol level after 48 h of incubation with buffalo plasma as the source of cholesterol. Overall there existed variations in different strains with respect to different characters of significance to be a probiotic.

Cost of autologous peripheral blood stem cell transplantation: the Norwegian experience from a multicenter cost study

High-dose therapy with autologous blood progenitor cell support is now routinely used for patients with certain malignant lymphomas and multiple myeloma. We performed a prospective cost analysis of the mobilization, harvesting and cryopreservation phases and the high-dose therapy with stem cell reinfusion and hospitalization phases. In total, 40 consecutive patients were studied at four different university hospitals between 1999 and 2001. Data on direct costs were obtained on a daily basis. Data on indirect costs were allocated to the specific patient based on estimates of relevant department costs (ie the service department's costs), and by means of predefined allocation keys. All cost data were calculated at 2001 prices. The mean total costs for the two phases were US$ 32,160 (range US$ 19,092-50,550). The mean total length of hospital stay for two phases was 31 days (range 27-37). A large part of the actual cost in the harvest phase was attributed to stem cell mobilization, including growth factors, harvesting and cryopreservation. In the high-dose chemotherapy phase, the most significant part of the costs was nursing staff. Average total costs were considerably higher than actual DRG-based reimbursement from the government, indicating that the treatment of these patients was heavily subsidized by the basic hospital grants.

Efficacy of 2-(3,4-dimethyl-2,5-dihydro-1h-pyrrole-2-yl)-1-methylethyl pentanoate in a murine model of invasive aspergillosis

2-(3,4-Dimethyl-2,5-dihydro-1H-pyrrole-2-yl)-1-methylethyl pentanoate, an antifungal compound, was found to be nontoxic to RAW cells up to a concentration of 312.5 microg/ml, whereas amphotericin B was lethal to all cells at 37.5 microg/ml. The treatment of Aspergillus fumigatus-infected mice with a dose of 200.0 mg of compound/kg of body weight increased their survival rate by 60%, with a decrease in CFU in organ tissues. The protection afforded by the compound against experimental aspergillosis was found to be dose dependent.

Effect of obesity on asthma among adult Indian women

OBJECTIVE

Both obesity and asthma are on the rise worldwide. This study examined the association between obesity and asthma prevalence in adult women in India.

METHODS

The analysis used information on 82 464 nonpregnant, ever-married women aged 15-49 y, included in India's 1998-99 National Family Health Survey. The effects of measured Body Mass Index (BMI) on reported asthma were estimated using logistic regression, after adjusting for tobacco smoking (active and passive), cooking smoke, age, education, work status, media habits, food habits, house type, separate kitchen, indoor crowding, religion, caste/tribe, household living standard, urban/rural residence, and geographic region.

RESULTS

Obese women (BMI>/=30.0 kg/m(2)) were about twice as likely as those with a normal BMI (18.5-25.0 kg/m(2)) to report suffering from asthma (OR=1.92; 95% CI: 1.40-2.65). The association between obesity and asthma remained strong and statistically significant even when the effects of other selected risk factors and potential confounders were controlled (OR=1.85; 95% CI: 1.30-2.63). Overweight women (25.0</=BMI<30.0 kg/m(2)) also reported significantly higher adjusted asthma prevalence than those with a normal BMI (OR=1.32; 95% CI: 1.07-1.63). Results hold in separate analysis for younger (15-29 y) and older (30-49 y) women.

CONCLUSION

The study finds a strong positive association between obesity and asthma among adult Indian women. To validate this relationship and to establish causality, prospective epidemiological studies, with better measures of overweight conditions and clinical measures of asthma, are needed in developing-country settings.

Design of liposomal aerosols for improved delivery of rifampicin to alveolar macrophages

The present study was aimed at preparation, characterization, and performance evaluation of rifampicin-loaded aerosolized liposomes for their selective presentation to alveolar macrophages, that being the most dense site of tuberculosis infection. Egg phosphatidylcholine (PC)- and cholesterol (Chol)-based liposomes were modified by imparting negative charge (using dicetylphosphate, DCP) or by coating them with alveolar macrophage-specific ligands (maleylated bovine serum albumin, MBSA; and O-steroyl amylopectin, O-SAP). The prepared formulations were characterized in vitro for vesicle morphology, mean vesicle size, and percent drug entrapment. Pressurized packed systems based on preformed liposomal formulations in chlorofluorocarbon aerosol propellants were prepared. In vitro airway penetration efficiency of the liposomal aerosols was determined by percent dose reaching the base of the lung, it was recorded 1.5-1.8 times higher as compared to plain drug solution-based aerosol. Percent viability of Mycobacterium smegmatis inside macrophages (in vitro) after administration of drug (in vivo) was in the range of 7-11% in the case of ligand-anchored liposomal aerosols, while it was recorded to be 45.7 and 31.6% in case of plain drug and plain neutral liposomal aerosol (based on PC:Chol)-treated macrophages. Results suggest the preferential accumulation of MBSA- and O-SAP-coated formulations in the lung macrophages, which was further reflected in the periodically monitored in vivo tissue distribution studies. Higher lung drug concentration was recorded in case of ligand-anchored liposomal aerosols and negatively charged liposomal aerosols (based on PC:Chol:DCP) as compared to plain drug and plain liposome-based aerosols. The drug was estimated in the lung in high concentration even after 24h. The drug localization index calculated after 6h was nearly 1.4- and 3.5-fold, respectively, for both ligand-appended liposome-based systems as compared to negatively charged and plain neutral liposome-based aerosolized systems. These results suggest that the ligand-anchored liposomal aerosols are not only effective in rapid attainment of high-drug concentration in lung with high population of alveolar macrophages but also maintain the same over prolonged period of time. The significance of targeting potential of the developed systems was established.

Results of displaced subcapital fractures treated by primary total hip replacement

We present morbidity, mortality and functional outcome in mobile, socially independent and alert patients with displaced subcapital hip fractures, treated by primary total hip replacement (THR). Fifty-one consecutive socially independent and mentally alert patients with displaced subcapital fractures were treated by primary THR, from April 1997 to March 2000, at a single hospital. Most patients were female (45/51) with an average age of 74 years. Patient hospital records were reviewed and patients interviewed by telephone. Functional outcome was assessed using Oxford hip score (OHS), short form 12 (SF12), and patient satisfaction. This study had a mean follow-up of 33 months (range 20-54). One patient with early dislocation went on to have recurrent dislocations. Two patients underwent revision surgery. Three patients died within 1 year of sustaining fracture. Function was comparable to elective THR in osteoarthritic patients. OHS correlated well with both SF12 and patient satisfaction. This study has the lowest reported dislocation rate (2%) and an acceptable 1-year mortality (6%) confirming the place of primary THR in treatment of these selected patients with a displaced hip fracture. The OHS proved a valuable instrument to assess function following THR in fracture patients.

Uric acid reduces exercise-induced oxidative stress in healthy adults

Uric acid (UA) possesses free-radical-scavenging properties, and systemic administration is known to increase serum antioxidant capacity. However, it is not known whether this protects against oxidative stress. The effects of raising UA concentration were studied during acute aerobic physical exercise in healthy subjects, as a model of oxidative stress characterized by increased circulating 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha) concentrations. Twenty healthy subjects were recruited to a randomized double-blind placebo-controlled crossover study, and underwent systemic administration of 0.5 g of UA in 250 ml of 0.1% lithium carbonate/4% dextrose vehicle or vehicle alone as control. Subjects performed high-intensity aerobic exercise for 20 min to induce oxidative stress. Plasma 8-iso-PGF2alpha concentrations were determined at baseline, after exercise and after recovery for 20 min. A single bout of high-intensity exercise caused a significant increase in plasma 8-iso-PGF2alpha concentrations from 35.0 +/- 4.7 pg/ml to 45.6 +/- 6.7 pg/ml (P<0.01). UA administration raised serum urate concentration from 293 +/- 16 to 487 +/- 16 micromol/l (P<0.001), accompanied by increased serum antioxidant capacity from 1786+/-39 to 1899 +/- 45 micromol/l (P<0.01). UA administration abolished the exercise-induced elevation of plasma 8-iso-PGF2alpha concentrations. High UA concentrations are associated with increased serum antioxidant capacity and reduced oxidative stress during acute physical exercise in healthy subjects. These findings indicate that the antioxidant properties of UA are of biological importance in vivo.

Influence of core suture material and peripheral repair technique on the strength of Kessler flexor tendon repair

The purpose of our study was to determine the most favourable combination of core suture material and peripheral repair technique for Kessler tendon repair. Thirty freshly thawed pig flexor tendons were repaired by a Kessler technique, either with braided polyester or monofilament nylon suture. A peripheral augmentation was done using one of the three techniques-running, cross-stitch and Halsted. All repairs were tested by cyclic loading, followed by load-to-failure. During cyclic loading six of the 15 tendons with a nylon core failed, but none with a braided polyester core. Irrespective of peripheral technique, the monofilament nylon core suture allowed early central cyclic gapping, resulting in failure of the repair. During load-to-failure testing, the running stitch proved weakest and the cross-stitch repair toughest.

Cost analysis of autologous peripheral blood stem cell transplantation for multiple myeloma

High-dose chemotherapy (HDC) with autologous peripheral blood stem cell (PBSC) support is a common but expensive treatment for various hematological malignancies. A prospective cost analysis of evaluation/mobilization and the HDC + PBSC phase for patients with multiple myeloma was performed. Eleven consecutive patients at the National University Hospital Oslo, taking part in a Nordic treatment protocol, were included in the analysis during the period from May 1999 to December 2000. Clinical and resource use data were obtained prospectively on a daily basis registration and from patient records. The total cost for the evaluation/mobilization and the HDC + PBSC phase varied from 22,999 US dollars to 61,722 US dollars (mean 38,186 US dollars; median 30,569 US dollars). The mean length of hospital stay for the evaluation/mobilization phase was 8 days (range 4-17 days) and for the HDC + PBSC phase 19 days (range 14-29 days). A statistically significant correlation was found between the length of hospital stay and hospital costs for both phases (P < 0.003 and P < 0.010, respectively). A large part of the actual cost in the harvest phase was attributed to stem cell mobilization, including growth factors, harvesting and cryopreservation. In the HDC + PBSC phase, the most important part of the cost was paying nursing care personnel.

Resolving appendicitis: role of CT

BACKGROUND

We assessed the role of computed tomography (CT) in the resolution of appendicitis.

METHODS

This was a retrospective study over 2.5 years involving 155 patients and 172 CT scans for suspected appendicitis in an emergency setting.

RESULTS

Sixty-nine studies were positive for appendicitis by CT criteria. Of these, 53 underwent surgery: 48 were positive for appendicitis, four had other pathologies (two with colon cancer, one with colitis, one with infectious enteritis), and one had a normal appendix that was removed. Three of the 69 patients were released or left the emergency room against medical advice. Twelve patients demonstrated acute appendicitis by CT criteria but were treated conservatively because their clinical conditions were stable; four of those patients had follow-up CT that showed resolution of findings. Six patients were followed clinically, without recurrence of symptoms, and two were lost to follow-up.

CONCLUSION

Resolving appendicitis is an entity that should be considered in a patient who has signs positive for appendicitis on CT but is doing well clinically. CT positive for appendicitis does not necessarily indicate surgery, and the decision for operation should depend on clinical and radiologic features.

Orthopaedic surgery in severe bleeding disorders: a low-volume, high-cost procedure

As more and more nations are scrutinizing their health care costs, attention has been focused on high-cost low-density disease. Assessment of actual total cost of care for haemophilia and its positive outcome becomes essential to justify support for these patients. In this study, we assessed hospital cost and diagnosis-related group (DRG) reimbursement for patients undergoing elective orthopaedic surgical procedures from May 1999 to December 1999. Hospital cost was assessed by a prospective microcost-analysis method. To identify real hospital costs, we performed registration of preoperative phase, operative phase and 1-year follow-up costs. Hospital cost included personnel costs and costs for clinical and laboratory procedures, blood products, prosthetic implants, coagulation factor concentrates and drugs. These data were compared with hospital DRG reimbursement. We included nine consecutive patients, with a mean age 38 years (19-54 years) who had had 10 major orthopaedic surgical procedures performed during the study period. Six patients had haemophilia A, two had haemophilia B and one had factor VII deficiency. Data analysis showed a mean cost of US$ 54,201 (range US$ 25,795-105,479; 1US$ = 8.5 NOK). The average actual hospital revenue (50% DRG reimbursement + income related to length of stay) was $4,730 (range $ 1,308-13,601). Our study confirms that orthopaedic surgery in patients with severe bleeding disorders puts the hospital to a considerable expense. Activity-based financing, as used in Norway, does not provide a proper reimbursement for this part of the haemophilia care.

Ureteric obstruction caused by pelvic actinomycosis

Ureteric obstruction is a well-known complication of actinomycosis, however its management in previous case reports has been very variable and sometimes mutilating. We report a rare case presenting with ischiorectal abscess that was successfully treated by JJ stenting and penicillin.

Enzymes and operons mediating xenobiotic degradation in bacteria

Aromatic hydrocarbons constitute a major group of environmental pollutants. Bioremediation appears to be the only viable alternative for large-scale decontamination. A number of bacteria have been identified that can degrade a variety of xenobiotics. Extensive studies of the enzymes and genes involved in degradation of aromatic hydrocarbons have revealed that the degradative enzymes could be broadly grouped into two major categories, peripheral and ring-cleavage enzymes. The peripheral enzymes are the ones that catabolize the pollutants initially to a metabolite that is further degraded. A majority of peripheral enzymes are oxygenases that hydroxylate the aromatic compounds, rendering them susceptible to the enzymes of ring-cleavage pathway. The genes of ring-cleavage enzymes have been shown to be highly conserved between different bacterial species. Presently, a number of constraints limit the use of available strains for efficient bioremediation. This review describes the enzymes and genes involved in xenobiotic degradation and underscores the importance of understanding the expression and regulation of genes encoding peripheral enzymes and their intelligent manipulation using recombinant DNA technology for efficient degradation of aromatic compounds.

A prospective cost evaluation related to allogeneic haemopoietic stem cell transplantation including pretransplant procedures, transplantation and 1 year follow-up procedures

The Norwegian Ministry of Health and Social Affairs recently introduced activity-based financing for hospitals partly based on diagnosis-related groups (DRG). We soon observed that there seemed to be a considerable discrepancy between the reimbursement amount and the real cost of allogeneic haemopoietic stem cell transplantation. It was therefore decided to undertake a prospective micro-cost analysis to define a more realistic reimbursement. To identify real costs, we undertook a registration of pre-transplant procedures, transplantation and 1 year follow-up costs, including harvesting, personnel costs, clinical and laboratory procedures, together with blood products and drugs related to patients and donors. These data were compared to hospital DRG reimbursement. This information was registered for 17 consecutive patients, with a mean age 40 years (range 17-58 years). Ten patients had chronic myeloid leukaemia, three had acute lymphatic leukaemia, two had acute myeloid leukaemia and two had myelodysplastic syndrome. The data analysis showed a mean cost of US$ 106825 (NOK 901982), (range US$ 42376-362430). The average actual hospital revenue (50% DRG reimbursement + income related to length of stay + special procedure funding) was US$ 36404 (range US$ 26228-55998). Activity-based financing as applied in Norway, under-compensates hospital costs for allogeneic bone marrow transplantation. The government should make realistic estimates of real costs before introducing financial reforms in the health care system.

A comparison of actual registered costs and costs derived from diagnosis-related groups (DRGs) for patients undergoing heart transplantation, lung transplantation, and thoracotomy for other lung diseases

The Norwegian health care system, like other health care systems in the world, is in the midst of a changing financial environment for hospital reimbursement for patient care. Since 1997 the Norwegian government has introduced a new financing model of block grant and activity-based financing. In this model, diagnosis-related groups (DRGs) play an important role in hospital financing. The initial motive for developing the DRGs was to improve hospital productivity and efficiency and to develop a tool to control increasing hospital costs better. We raised the question as to whether the DRG system in fact covers actual costs in patient groups undergoing heart transplantation (n = 12), lung transplantation (n = 4), and thoracotomy for other diseases (n = 10). A new prospective cost model was developed to measure actual costs related to individual patients. The patients were closely observed and the related data collected during the hospital stay. Each patient's hospital stay was divided into four different categories of resource requirements, defined as heavy intensive care, light intensive care, intermediate care, and ordinary care. In addition, the number of staff involved and the duration of surgery and procedures were recorded, as were medicine costs and material costs. Based on these data, the actual costs for each patient were calculated. These were then compared with the respective DRG reimbursement (100 % coverage) for the corresponding group. We found that the median cost for heart transplantation was US$ 50,590 (1 US$ = 7.5 NOK based on the exchange rate at the time of the study), while the respective DRG reimbursement was US$ 65,662. For lung transplantation, the respective figures were US$ 46,668 vs US$ 65,662, and for thoracotomy, US$ 24,307 vs. US$ 11,004. We found that our method was applicable to a hospital setting. DRG coverage for heart and lung transplantation seems to overestimate the actual costs. For the thoracotomy procedure, the DRG coverage did not cover the actual costs.

Ligand directed macrophage targeting of amphotericin B loaded liposomes

Two types of ligand anchored multilamellar liposomes (MLVs) containing amphotericin B (Amp B) were prepared. The MLVs consisting of soya phosphatidylcholine (PC) and cholesterol (Chol) were coated with O-palmitoyl mannan (OPM). Similarly, the MLVs with the same Amp B content consisting of soya PC, Chol and phosphatidylethanolamine (PE) were prepared and covalently anchored with p-aminophenyl-mannopyranoside (PAM). The surface modified MLVs and their plain counterparts were characterised for size, shape, lamellarity, entrapment efficiency and ligand density. The stability in serum and in vivo bio-distribution in albino rats were also determined. It was observed that extent of accumulation of liposomal Amp B in macrophage rich organs, particularly liver, spleen and lungs was significantly high when compared against the free drug. The rates and extent of accumulation were found to increase further on ligand anchoring. In either of the cases, the macrophagic uptake of ligand anchored liposomes was inhibited significantly on pre-injection of hydrolysed mannan, being suggestive of receptor mediated uptake of ligand anchored liposomes. Comparison of biodistruibution pattern of ligand anchored MLVs revealed that PAM linked liposomes exhibited a higher hepato-splenic accumulation where as drug accumulation in lungs was highest in the case of OPM coated liposomes. It was thus observed that mannopyranoside is a specific ligand for targeting bioactives to the macrophages of liver and spleen while OPM could preferentially negotiate the targeting of bioactives to the alveolar macrophages.

Anticonvulsant activity of p-chlorophenyl substituted arylsemicarbazones--the role of primary terminal amino group

A series of p-chlorophenyl substituted arylsemicarbazones were synthesized and evaluated for anticonvulsant activity. Most of the compounds provided significant protection against maximal electroshock-induced seizures (MES) at 100 mg/kg after 0.5 h and at 300 mg/kg after 4 h in both MES and pentetrazole-induced (PTZ) seizures. In the strychnine-induced seizures (scSTY), the majority of the compounds showed protection at 30 mg/kg. The compound 2 was active in both MES and PTZ tests. The study has shown that the terminal primary amino group is not necessary for anticonvulsant activity.

Need for bringing in a change in biochemistry curriculum to make it clinically oriented?

OBJECTIVES

This study was conducted to (a) assess the views of medical students and doctors regarding relevance of biochemistry training, (b) explore if they have any suggestion to bring in any improvement in contents of biochemistry curriculum and mode of teaching.

METHODS

In 1997-98, a structured questionnaire was filled up by 114 medical students and 118 doctors.

RESULTS

As many as 62/114 (55%) medical students and 40/118 (34%) doctors believed that it is not important to remember minute details of biochemical reactions (p value < 0.0001). Among medical students, 108/110 (98.2%) agree that a clinician should be invited to seminars for developing skills of interpretation of laboratory investigations; whilst 110/118 (93.2%) doctors expressed similar view, p value ns. Approximately 92% responders favored that departments biochemistry and physiology should co-ordinate on the topics of common interest in order to save time and effort. What is the most informative and effective way of teaching biochemistry?' in response to this question only 0.9% responders opted lecture as the best option. Seminars with active participation of medical students was preferred by 93.2% responders. About 6.9% responders reckoned that symposium prepared by a more than one teacher. In response to the question whether it is possible to cover pre-clinical subjects in 12 months so as to allow spiral mode of curriculum, 73% of all the responders agreed that it would be good idea, there was no difference of opinion among the doctors and medical students. On the other hand, 27% were strongly opposed to this suggestion.

CONCLUSIONS

We suggest that there is a need to modify the contents, methods of teaching, and curriculum organization of training in clinical biochemistry. How best the curriculum can be made problem oriented needs to be debated among medical educationists.

Controlled and targeted drug delivery strategies towards intraperiodontal pocket diseases

Advances in the understanding of the aetiology, epidemiology, pathogenesis and microbiology of periodontal pocket flora have revolutionized the strategies for the management of intraperiodontal pocket diseases. Intra-pocket, sustained release, drug delivery devices have been shown to be clinically effective in the treatment of periodontal infections. Several degradable and non-degradable devices are under investigation for the delivery of antimicrobial agents into the periodontal pocket including non-biodegradable fibres, films (biodegradable and non-biodegradable), bio-absorbable dental materials, biodegradable gels/ointments, injectables and microcapsules. With the realization that pocket bacteria accumulate as biofilms, studies are now being directed towards eliminating/killing biofilm concentrations rather than their planktonic (fluid phase) counterparts. Intraperiodontal pocket drug delivery has emerged as a novel paradigm for the future research. Similarly, bioadhesive delivery systems are explored that could significantly improve oral therapeutics for periodontal disease and mucosal lesions. A strategy is to target a wide range of molecular mediators of tissue destruction and hence arrest periodontal disease progression. Research into regenerating periodontal structures lost as a result of disease has also shown substantial progress in the last 25 years.

Analgesic activity of thioureido derivatives of arylsemicarbazones

The synthesis of a series of novel arylsemicarbazones derived from 4-aminoacetophenone and their evaluation for analgesic activity are described. The p-chloro-substituted derivatives (12-15) are extremely potent compounds as compared to standard drugs currently being used.

Synthesis of aryl semicarbazone of 4-aminoacetophenone and their anti-HIV activity

The thioureido derivative of 4-aminoacetophenone aryl semicarbazone have been prepared. These derivatives have been characterised on the basis of different physicochemical evidences. The anti-HIV-1 (HTLV-IIIB) and -HIV-2 (ROD) activity and cytotoxicity of the compounds were tested. The compound VII and VIII showed maximum protection among the series.

Self-Preservation of the Drop Size Distribution Function and Variation in the Stability Ratio for Rapid Coalescence of a Polydisperse Emulsion in a Simple Shear Field

Coalescence of oil-in-water emulsion droplets in a simple shear flow produced by a Couette device is considered. A phase Doppler anemometer was used to measure the droplet size distribution as a function of time for shear rates ranging from 55 to 213 s-1 and for sodium chloride salt concentrations from 0.095 to 0.6 M. The initial droplet size distribution was log-normal. During the coalescence process, the size distribution was self-preserving in accordance with D. L. Swift and S. K. Friedlander's analysis [J. Colloid Sci. 19, 621 (1964)]. In the limiting case of negligible repulsive force due to the electric double layer, the calculated stability ratios, corrected for droplet polydispersity, agree well with the theoretical analyses of G. R. Zeichner and W. R. Schowalter [AIChE J. 23, 243 (1977)] and D. L. Feke and W. R. Schowalter [J. Fluid Mech. 133, 17 (1983)] for the case of solid particle aggregation. The good agreement between the stability ratios for the case of coalescence of droplets in the present study and those for aggregation of solid particles indicates that resistance to film deformation and thinning present in the case of coalescence is not important compared with the collision process. Copyright 1998 Academic Press. Copyright 1998Academic Press

Anticonvulsant activity of thioureido derivatives of acetophenone semicarbazone

A series of thioureido derivatives of acetophenone semicarbazone were synthesized and evaluated for anticonvulsant activity. Some compounds provided significant protection against maximal electroshock (MES) and subcutaneous pentylenetetrazol (scPTZ) induced seizures. The compound (2e) was the most active compound in the series with a dose of 30 mg kg-1 and ED50 23.5 mg kg-1 and equipotent to phenytoin ED50 23.2 mg kg-1. The toxicity of the compounds was assessed by determination of their approximate TD50 and LD50 values in order to have a better assessment of their pharmacological profile and protective index.

Anisotropy of an 192iridium high dose rate source measured with a miniature ionization chamber

The anisotropy of a high dose rate (HDR) 192Ir source was measured in air and in water using a miniature (0.147 cm3) ionization chamber. Measurements were made at a distance of 5 cm from the source center at polar angles from 10 degrees-170 degrees. The anisotropy was found to be less pronounced in water, and the anisotropy is asymmetric about the transverse axis. The results agree with previous ionization chamber and TLD measurements to within +/- 4%. Mean anisotropy factors were determined at each angle from all existing data at 5 cm distance, and compared to published Monte Carlo calculations, and to the values used in the microSelectron HDR brachytherapy planning system (BPS). The Monte Carlo photon transport code appears to systematically underestimate the anisotropy factor by up to 4% in the forward direction and overestimate it by up to 3% in the backward direction. The mean anisotropy factors also indicate that the BPS systematically underestimates the anisotropy factor by up to 3% in the forward direction, and overestimates it by up to 15% in the backward direction. However, the 15% difference occurs at 180 degrees where it is not likely to be clinically significant.

Quantitative evaluation of radiochromic film response for two-dimensional dosimetry

Radiochromic film (RCF) is attractive as a thin, high resolution, 2D planar dosimeter. We have studied the uniformity, linearity, and reproducibility of a commercially supplied RCF system (model MD-55). Forty 12 cm long strips of RCF were exposed to uniform doses of 6 MV x rays. Optical density (OD) distributions were measured by a helium-neon scanning laser (633 nm) 2D densitometer and also with a manual densitometer. All film strips showed 8%-15% variations in OD values independent of densitometry technique which are evidently due to nonuniform dispersal of the sensor medium. A double exposure technique was developed to solve this problem. The film is first exposed to a uniform beam, which defines a pixel-by-pixel nonuniformity correction matrix. The film is then exposed to the unknown dose distribution, rescanned, and the net OD at each pixel corrected for nonuniformity. The double exposure technique reduces OD/unit dose variation to a 2%-5% random fluctuation. RCF response was found to deviate significantly from linearity at low doses (40% change in net OD/Gy from 1 to 30 Gy); a finding not previously reported. To study the tradeoff between statistical noise and spatial resolution, OD was averaged over blocks of adjacent 50 microns pixels (ranging from 1 x 1 to 10 x 10 pixels). Reproducibility, defined as the standard deviation of repeated single-pixel measurements on separate film pieces, was 2% at 30 Gy for a resolution of 0.25 mm. With careful correction for nonlinearity and nonuniformity, RCF is a promising quantitative 2D dosimeter for radiation oncology applications.

Experimental validation of Monte Carlo dose calculations about a high-intensity Ir-192 source for pulsed dose-rate brachytherapy

Despite widespread use of high-intensity Ir-192 remotely afterloaded sources, no published measured or calculated dose-rate tables for currently used source designs are available. For a pulsed dose-rate Ir-192 source, both transverse axis (0.5-10 cm) and two-dimensional polar dose-rate profiles (1.5, 3, and 5 cm) were measured with thermoluminescent dosimetry in a solid water phantom. Dose rates were normalized to measured air-kerma strength, and the source geometry was verified by pinhole autoradiography and transmission radiography. At each measurement point, dose rates were calculated by a Monte Carlo photon transport (MCPT) code, which realistically modeled the experimental phantom, source, and detector geometry. Agreement between MCPT absolute dose-rate calculations and measurements averaged 3% and was less than 5%, demonstrating that Monte Carlo simulation is an accurate and powerful tool for two-dimensional dosimetric characterization of high activity Ir-192 sources.

Instrumentation and dosimeter-size artifacts in quantitative thermoluminescence dosimetry of low-dose fields

Thermoluminescence dosimetry is extensively used for quantitative dose measurements in various irradiation fields such as dosimetry of brachytherapy sources. In this application, small doses on the order of 0.5 cGy must be accurately measured, which requires careful control of instrumentation, energy-dependence, and nonlinearity of detector response. Several investigators have observed the presence of some undesirable signals when the thermoluminescent dosimeters (TLDs) were read without any nitrogen gas flow in the TLD reader. Others have indicated that the "prereadout" annealing technique is the same as the "preirradiation" technique for doses above 10 cGy, but they have not extended their study to lower doses. The goal of this study is to investigate dependence of sensitivity and linearity of the TLD response to the flow of nitrogen gas in the TLD reader at low dose level, annealing technique, and TLD size. The effect of nitrogen flow sensitivity and linearity of two different sizes of lithium fluoride TLD-100 chips has been studied. Our data indicate a large standard deviation of TLD sensitivity, up to a factor of 2, when TLDs were read without nitrogen gas flow in the TLD reader. In addition, a large deviation from linearity was observed for doses below 5 cGy. When the reading-chamber was purged with nitrogen gas, dispersion of the responses of the TLDs that were exposed to the same dose fell to within 5%. At precision levels of 2% and 5%, the low dose limits are 1 cGy and 0.5 cGy, respectively, for large chips and 15 cGy and 1 cGy for small chips, if TLDs are read with nitrogen gas flow in the TLD reader.(ABSTRACT TRUNCATED AT 250 WORDS)

A secondary air kerma strength standard for Yb-169 interstitial brachytherapy sources

Ytterbium-169 (169Yb) is a promising new intermediate low-energy isotope for interstitial implantation. To date, no air kerma strength (SK) standard for this source exists that can serve as a sound foundation for comparing various dose measurements and theoretical calculations. We have solved this problem by adapting the free air measurement technique of Goetsch et al, originally developed for 192Ir. Using a 100 cm3 spherical ion chamber with NIST traceable external beam calibrations in a free air geometry, we have measured the air kerma strength of six different source batches (two type 6 batches, three type 8 batches, and one experimental high-intensity source). Room scatter corrections, derived from an empirical fit to the data (following Goetsch et al) and/or directly by Monte Carlo simulation, yielded identical results with a reproducibility of 1%. The ratio [SK/Avendor] of measured SK to the vendor's contained activity assay averaged 1.554 cGy cm2 mCi-1 h-1 (0.0420 microGy m2 MBq-1 h-1), in conflict with the expected value of 1.34 (0.0362), derived from Monte Carlo calculations. The measured [SK/Avendor] for the type 8 seeds varies by as much as 10% whereas the SK/dose calibrator reading ratio varies by no more than 0.3%, suggesting that the reproducibility of Avendor is relatively poor. These discrepancies may help explain the variation (as large as 28%) in published dose rate constants for 169Yb.

A comparative study of dosimetric properties of Plastic Water and Solid Water in brachytherapy applications

In this study the dosimetric properties of Plastic Water and Solid Water phantom materials are evaluated using Monte Carlo photon transport simulations. In particular, their water-equivalence with respect to absorption and attenuation of photons in the brachytherapy energy range are examined. For the given chemical compositions of the materials, the linear attenuation coefficients were calculated for photons of 1 keV-2 MeV. Moreover, absorbed doses to water in each phantom material were calculated at distances of 0.5-12.0 cm from point sources of 20 keV to 60Co gamma rays. These results show that at low photon energies (below 100 keV), there are substantial differences (up to a factor of 5) between the absorbed dose in Plastic Water and that in liquid water. The differences decrease as photon energy increases, and they become insignificant at 60Co gamma rays, as claimed by the manufacturer. In contrast, calculations show that the difference in absorbed dose in Solid Water from that in liquid water, over the entire range of photon energies employed in this study, is less than 25%. The results of this study demonstrate the necessity of careful dosimetric evaluation of a new phantom material, before its clinical application, particularly in energy ranges outside those referred to by the manufacturer.

Necrotizing enteritis simulating Pig-Bel disease in northern India

OBJECTIVE

A clinicopathological study of patients presenting with necrotizing enteritis, similar to the Pig-Bel disease of Papua New Guinea.

METHODS

A clinicopathological study of 95 patients presenting in last ten years with acute abdominal pain with diarrhea and/or bleeding per rectum and vomiting and found to have lesions similar to Pig-Bel disease.

RESULTS

89% of the patients were young adult vegetarians from lower socio-economic strata. 94% of cases presented between May and August every year showing a marked seasonal variation. Jejunum was the most common site (95%) involved. Gross examination showed blackish brown 'skip' lesions with gangrene and perforations. Histology showed marked necrosis and congestion of all the layers with mucosal ulcerations.

CONCLUSION

A disease simulating Pig-Bel disease occurs in India. It is more common in young adult vegetarians and may have a different etiology from that proposed in endemic regions.

Dosimetric characteristics, air-kerma strength calibration and verification of Monte Carlo simulation for a new Ytterbium-169 brachytherapy source

PURPOSE

Ytterbium-169 (169Yb) is a promising new isotope for brachytherapy with a half life of 32 days and an average photon energy of 93 KeV. It has an Ir-192-equivalent dose distribution in water but a much smaller half-value layer in lead (0.2 mm), affording improved radiation protection and customized shielding of dose-limiting anatomic structures. The goals of this study are to: (a) experimentally validate Monte Carlo photon transport dose-rate calculations for this energy range, (b) to develop a secondary air-kerma strength standard for 169Yb, and (c) to present essential treatment planning data including the transverse-axis dose-rate distribution and dose correction factors for a number of local shielding materials.

METHODS AND MATERIALS

Several interstitial 169Yb sources (type 6) and an experimental high dose-rate source were made available for this study. Monte-Carlo photon-transport (MCPT) simulations, based upon validated geometric models of source structure, were used to calculate dose rates in water. To verify MCPT predictions, the transverse-axis dose distribution in homogeneous water medium was measured using a silicon-diode detector. For use in designing shielded applicators, heterogeneity correction factors (HCF) arising from small cylindrical heterogeneities of lead, aluminum, titanium, steel and air were measured in a water medium. Finally, to provide a sound experimental basis for comparing experimental and theoretical dose-rate distributions, the air-kerma strength of the sources was measured using a calibrated ion chamber. To eliminate the influence of measurement artifacts on the comparison of theory and measurement, simulated detector readings were compared directly to measured diode readings. The final data are presented in the format endorsed by the Interstitial Collaborative Working Group.

RESULTS

The in-air calibration revealed that the air-kerma strength per unit activity (mCi), as quoted by the vendor, varied from 1.30 to 1.57 cGy.cm2/mCi.h depending on seed design. The maximum difference between measured and MCPT-simulated absolute diode readings on the transverse axis was less than 2%, indicating that MCPT accurately predicts dose rate in medium for brachytherapy sources in this energy range. Comparison of measured and simulated HCFs for each of the 16 different cylindrical heterogeneities demonstrated 1-3% agreement. The HCFs vary by as much as 200% with respect to distance and by as much as 48% as a function of disk diameter, showing that HCF is strongly dependent on heterogeneity location and lateral dimensions as well as thickness. The dose-rate constant for water medium was found to be 1.225 cGy/h per kerma unit air-strength and 1.962 cGy/h per unit mCi as measured by the vendor.

CONCLUSION

Monte Carlo simulation is an accurate and powerful tool for dosimetric characterization of brachytherapy sources in this energy range. Thin lead foils produce shielding factors comparable to standard shielded applicators for 137Cs. Meaningful theoretical absolute dose calculations in brachytherapy require accurately implemented air-kerma strength standards.

Prolonged peritoneal dialysis in acute renal failure using Tenckhoff catheter

The changing spectrum of acute renal failure (ARF), in children has necessitated the support by peritoneal dialysis (PD) for a longer duration. Use of permanent catheters like Tenckhoff catheter can overcome many of the problems associated with the prolonged use of temporary catheters. Thirty one infants and children with mean (SD) age of 49.3(39.4) months were subjected to PD using surgically placed Tenckhoff catheter. Catheters were put under general anesthesia in 28 patients and under local anesthesia in 3 patients. The technique of catheter insertion has been described in detail. All the catheters, except one, functioned immediately after the insertion. There was no intraperitoneal hemorrhage, dialysate leak or poor catheter drainage. The mean (SD) duration of catheter placement for PD was 11.3 (16.1) days (range 2.90 days). There were 6 episodes of infections (19.2%), peritonitis in 4 (12.8%) and exit site infection in 2 (6.4%). In 2 patients, infection episodes did not respond to antibiotics and the catheter had to be removed. There was no mortality due to complications of PD procedure and catheter insertion. Acute intermittent PD using surgically placed Tenckoff catheter was done safely for prolonged duration and also had additional advantages of good catheter drainage and no intraperitoneal hemorrhage.