Computer-aided design of dry powder inhalers using computational fluid dynamics to assess performance

Dry powder inhalers (DPIs) are gaining popularity for the delivery of drugs. A cost effective and efficient delivery device is necessary. Developing new DPIs by modifying an existing device may be the simplest way to improve the performance of the devices. The aim of this research was to produce a new DPIs using computational fluid dynamics (CFD). The new DPIs took advantages of the Cyclohaler® and the Rotahaler®. We chose a combination of the capsule chamber of the Cyclohaler® and the mouthpiece and grid of the Rotahaler®. Computer-aided design models of the devices were created and evaluated using CFD. Prototype models were created and tested with the DPI dispersion experiments. The proposed model 3 device had a high turbulence with a good degree of deagglomeration in the CFD and the experiment data. The %fine particle fraction (FPF) was around 50% at 60?L/min. The mass median aerodynamic diameter was around 2.8–4?μm. The FPF were strongly correlated to the CFD-predicted turbulence and the mechanical impaction parameters. The drug retention in the capsule was only 5–7%. In summary, a simple modification of the Cyclohaler® and Rotahaler® could produce a better performing inhaler using the CFD-assisted design.     

Outcome of conservative treatment of primary vesicoureteral reflux in 87 Thai children in a single center

AIM: To evaluate the outcome of primary vesicoureteral reflux (VUR) using conservative treatment. METHODS: Eighty-seven children with primary VUR who had been treated with a conservative medical regimen and monitored through a yearly cystogram were recruited for the study. The study was conducted at the Pediatric Nephrology Clinic in Songklanagarind Hospital, the major tertiary care center in southern Thailand. Statistical analyses using Kaplan-Meier survival curves, chi-squared test, Fisher's exact test and multivariate analysis with Cox regression were performed. RESULTS: The study group consisted of 41 boys and 46 girls, with a total of 133 VUR. The age of the boys was significantly lower than that of the girls (P < 0.001). Resolution of the low grades (grades I-III) of VUR was significantly more frequent than that of the high grades (grades IV-V) (68/95, 72%vs 14/38, 37%; P < 0.001). Using the Kaplan-Meier survival analysis and log-rank test, the resolutions of VUR in boys versus girls, and age <1 years versus >or=1 years were not significantly different (P = 0.2252 and 0.4756, respectively). Low-grade VUR and unilateral VUR had significantly higher probabilities of resolution than high-grade VUR and bilateral VUR, respectively (P = 0.0041 and 0.0467, respectively). Multivariate Cox regression analysis indicated that among low-grade VUR, boys and unilateral VUR had significantly higher probabilities of resolution. Among the high-grade VUR, neither sex nor laterality had a significant effect on the probabilities of VUR resolution. CONCLUSION: This study offers more evidence that children with low-grade VUR have a higher chance of reflux resolution if they are boys and have only unilateral VUR. There is still no good guide for resolution of reflux in children with high-grade VUR.     

Rural-urban differentials of premature mortality burden in south-west China

Background  

Yunnan province is located in south western China and is one of the poorest provinces of the country. This study examines the premature mortality burden from common causes of deaths among an urban region, suburban region and rural region of Kunming, the capital of Yunnan.     

Dynamic mutation loci: allele distributions in different populations

To assess the relative contributions of trans -acting factors (replication and repair functions) and cis -acting elements (repeat and flanking DNA composition) to the mechanism of trinucleotide repeat sequence mutation we have analysed the distribution of copy number polymorphisms at 12 loci associated with dynamic mutations in 15 populations of different ethnic origins. Genome wide instability of repeats in a particular population would be evidence of trans -acting factor instigation of the mutation process, whereas instability at a particular locus (perhaps even in several populations) would be evidence that the composition of the particular locus was the most significant factor contributing to mutation. The FRA16A locus is highly polymorphic in only the European population. Some other loci exhibit distinct distributions of alleles between different populations. Therefore sequences in the vicinity of the repeat - the cis component of a particular locus - appear(s) to be more important in the mutation mechanism than sporadic genome-wide instability induced by trans -acting factors such as the DNA mismatch repair enzymes.     

Nonshaved cranial neurosurgery

BACKGROUND: Preoperative shaving for cranial neurosurgical procedures is still recommended in textbooks. There are reports demonstrating the success of nonshaved surgery. The objective of this study was to compare the surgical infection rate of cranial neurosurgical procedures with two different scalp preparations: shaved or nonshaved. METHODS: Clinical trials of nonshaved scalp preparation were performed in non-emergency cranial neurosurgical procedures at Songklanagarind Hospital from August 1994 to December 1996. Patients were entered in the nonshaved group using the following exclusion criteria: immunocompromised host, presence of infectious diseases, surgery with foreign material insertion, multiple operations within 1 month, and presence of traumatic wound around the operative site. Patients who survived less than 1 month after surgery were excluded except in cases where death resulted from intracranial infection. RESULTS: During the 29-month period, 225 of 1,244 cranial neurosurgical procedures were selected for study. Ages ranged from 4 to 86 years. Brain tumors were encountered in 57%. In the nonshaved group, there were 89 procedures (80 cases), compared with 136 procedures (123 cases) in the shaved group. Surgical infection rates were 3.37% and 5.88%, respectively (p>0.05). CONCLUSIONS: Nonshaved scalp preparation is recommended for nonemergency cranial neurosurgical procedures.     

Menopausal symptoms in a hospital-based sample of women in southern Thailand.

OBJECTIVE: To evaluate menopausal symptoms and quality of life in middle-aged women. STUDY DESIGN: Hospital-based, cross-sectional study. METHODS: A survey was conducted among 270 women aged 45-65 years who attended the gynecological and menopause clinic, Songklanagarind Hospital. We used the MENQOL questionnaire as the instrument. RESULTS: The average age at menopause of the postmenopausal women was 48.7 years (range 40-57 years). The prevalences of the classical menopausal symptoms--hot flushes, night sweats, and vaginal dryness--in the women aged 45-65 years were 36.8%, 20.8 and 55.3%, respectively. The three most prevalent symptoms in perimenopause were aching in muscles and joints, experiencing poor memory, and change in sexual desire. Within the four domains (vasomotor, psychological, physical, and sexual symptoms), more suffering was reported in the perimenopausal and postmenopausal subjects than in the premenopausal subjects (p < 0.001). CONCLUSIONS: Peri- and postmenopausal women had a significant decrease in quality of life compared to premenopausal women.     

Correlation between the median particle size of chewed frankfurter sausage and almonds during masticatory performance test

The correlation between chewing and gastric function is best reflected when the same food type is used during both tests. We proposed frankfurter sausage as test food for masticatory performance as it can also be used in gastric emptying test. The suitability of frankfurter sausage to determine masticatory performance, however, has never been examined. To examine the correlations between the median particle size of frankfurter sausage and almonds (as standard test food) after different numbers of chewing cycles. Twenty‐seven subjects performed masticatory performance tests by chewing 2 types of test foods, that is, a piece of almond or 5‐g frankfurter sausage cubes placed in a sealed latex bag, for 5 and 15 chewing cycles. For each individual, right and left sides were tested separately. Chewed samples obtained from both sides were pooled. Median particle sizes were determined using a multiple sieving method. Spearman’s rank correlation was used to examine any correlation between median particle sizes of the 2 test foods after 5 and 15 cycles. Median particle sizes after 5 and 15 cycles were 2.04 ± 0.87 and 0.95 ± 0.58 mm for almonds and 4.16 ± 0.19 and 3.73 ± 0.25 mm for frankfurter sausage, respectively. Significant correlations were observed between the median particle size of chewed frankfurter sausage after 15 cycles and that of chewed almonds after 5 and 15 cycles (r = .76, P < .01 and r = .52, P = .01, respectively). Frankfurter sausage chewed for 15 cycles may be suitable for the determination of masticatory performance in conjunction with gastric emptying test.