Study of freeze-dried quercetin-cyclodextrin binary systems by DSC, FT-IR, X-ray diffraction and SEM analysis

The inclusion behavior of 2-hydroxypropyl beta-cyclodextrin (HPbetaCD) and beta-cyclodextrin (betaCD), in solution and solid-state was studied towards a poorly water-soluble bioflavonoid, quercetin (QURC), chemically 3,3',4',5',7-pentahydroxy flavone. Drug-cyclodextrin solid systems were prepared by freeze-drying. Phase solubility study was used to evaluate the complexation in solution, of two cyclodextrins, i.e., betaCD and HPbetaCD. The stoichiometry and stability constants of QURC-betaCD (1:1 and 402M(-1)) and QURC-HPbetaCD (1:1 and 532M(-1)) complexes were calculated by phase solubility method. The formation of inclusion complexes with betaCD and HPbetaCD in the solid-state were confirmed by infrared spectroscopy, differential scanning calorimetry, X-ray diffractometry, and scanning electron microscopy (SEM).     

Effects of polyethyleneglycol-superoxide dismutase (PEG-SOD) and pentoxifylline on small intestinal anastomoses established in the 24th hour of reperfusion: an experimental study in rats

In a previous study, we had shown that anastomoses established in the 24th hour of reperfusion healed less than the ones established in earlier periods. In this study, we aimed to assess the impacts of polyethyleneglycol-superoxide dismutase (PEG-SOD), a free oxygen radical scavenger and of pentoxyfilline, a methyl-xanthine derivative on anastomotic healing at 24th hour of reperfusion. 18 Wistar-albino rats were divided into 3 groups (n = 6). In all groups superior mesenteric artery was occluded for 40 minutes and the intestine was reperfused for 24 hours. Rats were relaparotomized in the 24th hour and small intestinal anastomoses were established. In Sham group, saline (0.5ml); in Group PTX, pentoxyfilline (25mg/kg); and in Group PGS, PEG-SOD (1,500U/kg) was administered intravenously 20 minutes before anastomoses. In the 5th day, anastomotic healing was evaluated by bursting pressures and hydroxyproline contents. Results were analized by Mann-Whitney U test, p < 0.05 was considered significant. Both of average bursting pressures and average hydroxyproline contents were highest in Group PGS (240 mmHg +/- 23.9; 7.71 +/- 0.68 micromol/g-tissue), followed by sham group (168.3 +/- 18.3 mmHg; 5.94 +/- 0.62 micromol/g-tissue) and Group PTX (83.8 +/- 9.2 mmHg, 5.94 +/- 0.62 micromol/g-tissue). Differences of these two parameters between all groups were statistically significant (p < 0.05). Best anastomotic healing in the 24th hour of reperfusion was achieved by PEG-SOD administration, whereas pentoxyfilline did not favor the healing.     

Clinical and histopathological correlation of nasal polyps: are there any surprises?

Nasal polypectomy is a common operation. There is debate about whether all nasal polyps removed at operation should be sent for histopathological examination. To investigate this, a prospective study was performed to check the correlation of clinical and histopathological examination. Three hundred and forty-four nasal polypectomy specimens during the period from September 1997 to September 1999 were sent for histopathological diagnosis, with the clinical diagnosis documented on the pathology form. The clinical diagnosis was then correlated with the histological diagnosis. Three hundred and twenty-eight specimens were diagnosed as inflammatory polyps and 16 as tumours, of which seven were malignant. There was a good correlation between the clinical and histological findings in 340 cases. There was disagreement between the forms and reports in four cases. When the notes were consulted, three cases had forms that were incorrectly filled in. There was only one unsuspected case of inverted papilloma in a polyp specimen, which looked like a benign inflammatory polyp. This study indicates there is a 99.7% correlation between clinical and histopathological diagnosis.     

Osteopoiesis: the early development of bone cells

An understanding of the disorders of bone formation clearly requires insights into the complex regulatory events occurring during the evolution of bone precursor cells into osteoblasts. Moreover, a rational approach to therapeutic interventions that might alter the clinical course of bone disorders must take into consideration the exact nature of the developmental control mechanism(s) being affected during the disease process. The process of osteopoiesis involves the proliferation and maturation of primitive precursor cells into functional osteoblasts. The bone cell lineage originates from mesenchymal stem cells that commit to the osteogenic cell lineage becoming osteoprogenitor cells, preosteoblasts, osteoblasts, and osteocytes. In order to understand how different regulatory signals coordinate bone cell development, it is important to study the responses of bone progenitor cells to different microenviromental signals. This requires that lineage markers be identified for the various populations of bone cells and their precursors, that cell separation techniques be established so that cells of the osteogenic lineage can be purified at different stages of differentiation, and that these isolated cells are studied under serum-free, chemically defined conditions. This review focuses on the current understanding of bone progenitor cell development, examining the various types of precursor cells, their responses to cytokines and other extracellular influences, and recent observations on the biochemical and molecular control of lineage-specific gene expression. Although the emphasis is on human cells, the importance of work using rodent cells goes without saying, and is addressed where relevant.     

Bilateral defects of the tegmen tympani associated with brain and dural prolapse in a patient with pulsatile tinnitus

A pulsating ear drum is a rare otological finding and usually indicates a vascular pathology. We report the case of a woman who presented with pulsatile tinnitus following an upper respiratory tract infection. She was found to have bilateral pulsating tympanic membranes on otological examination, in association with bilateral dehiscence of the tegmen tympani and a spontaneous encephalocele on the right side and a meningocele on the left side, demonstrated on computerized tomography (CT) scan of her temporal bones.     

Acceptance and use of communal filtration units in guinea worm eradication

The use of cloth to filter drinking water for guinea worm prevention is a long-standing control strategy and part of a mixed approach that includes the provision of wells, chemical treatment of ponds and protection of water supplies. As the goal of eradication nears, filters are a useful component of the quick response needed to implement case containment at village level. Various designs of filters have been used. Individual hand-sewn filters (HSFs) using monofilament nylon cloth have played a central role in village-based control to date. Problems such as the need to continually reinforce correct habitual filtering behaviour have led to the design and testing of communal filtration units (CFUs) made from metal oil drums with filter cloth inserted in the top and spigots at the bottom. Approximately one year after the introduction of CFUs in the South-western Zone of Nigeria, village surveys were conducted to determine opinions about the two types of filters and reported use. Percentage use was calculated by dividing the number of times water was filtered in the week preceding the survey by the number of times water was collected in that week. Those respondents with access to CFUs filtered an average of 91.9% of the time compared to 75.7% of those with HSFs. Using the village as level of analysis since it was the main level of intervention, the average percent of times villagers in CFU villages filtered was 91.1% compared to 77.8% in HSF villages. Although CFUs were more expensive in the short run, their greater acceptance by villagers is a factor to recommend their wider implementation to speed up elimination of guinea worm from Nigeria.