Effect of Polishing Technique and Brushing on Surface Roughness of Acrylic Resins

Purpose: This study evaluated the abrasion resistance of acrylic resin to routine dental brushing procedures using different dentifrices after the resin surface had been chemically or mechanically polished.
Materials and Methods: Eighty specimens were prepared using heat-polymerizing (HP) and autopolymerizing (AP) acrylic resin, and immediately submitted to grinding with abrasive stones and disks. The specimens were divided into two groups: the first group was mechanically polished (MP) using pumice slurry, and the second group was chemically polished (CP) using heated monomer. After polishing, the specimens were submitted to 30,000 brushing cycles. Surface roughness was measured after polishing and brushing procedures, using a Surfcorder SE 1700 rugosimeter. Data were statistically analyzed by ANOVA (α= 0.05).
Results: There were significant differences in surface roughness between polishing with MP and CP ( p < 0.05). Significant differences in surface roughness were also found between brushing with MFP dentifrice and Tartar Control dentifrice ( p < 0.05).
Conclusion: MP produced smoother surfaces than CP, and surface roughness as a result of polishing technique was not influenced by acrylic resin type. Even though MP resulted in smoother surfaces initially, subjecting the acrylic resin to dentifrice brushing negated this advantage.     

Generalized osteoporosis in a patient with oculocutaneous hypopigmentation syndrome (OOCHS), without cerebral defects A new syndrome?

An 8-year-old male patient presented a unique pattern of congenital anomalies. Prominent findings included a combination of severe osteoporosis and congenital oculocutaneous hypopigmentation. The patient may represent a hitherto undescribed syndrome of unknown etiology.     

Effect of food restriction on hemorheological variables in a rat model of spontaneous hypertriglyceridemic obesity and diabetes

Few studies have been performed in humans to investigate the effect of caloric restriction and consequent biomass reduction on hemorheologic parameters and their results are not concurrent. In a previous paper we analyzed the rheological behavior of the blood in the IIMb/Fmbeta inbred obese and hypertriglyceridemic strain in relation to its eumetabolic control [G.N. Hernández, C. Dabin, M.C. Gayol and M.L. Rasia, Hemorheological variables in a rat model of hypertriglyceridemic obesity and diabetes, Veterinary Res. Commun. 26 (2002), 625-635]. In this obese line it was shown a higher blood and plasma viscosity and an impaired red cell deformability compared to the eumetabolic one. The increased plasma viscosity was significantly and positively associated with fibrinogenaemia and lipidaemia and the impaired erythrocyte deformability with cholesterolemia and hypertriglyceridaemia. The present study has been designed to find out the effect of a 30% food restriction on several biochemical and hemorheological parameters of these obese rats. Restriction resulted in a mean body weight 45% lower than ad libitum controls, preventing obesity and hypertriglyceridemia with minimal effect on glucose metabolism. Regarding hemorheological parameters, caloric restriction led to a decrease in blood viscosity, due to the reduction in erythrocyte concentration, but not because of any improvement in erythrocyte deformability.     

Eye movement-related modulation of trigeminal neuron activity during active sleep and wakefulness

The amplitude of electrically-evoked mass action potentials recorded in the spinal cord and brainstem has been reported to decrease only during eye movement events of active sleep. In contrast, we have reported that the response of trigeminal sensory neurons to peripheral stimuli is modulated throughout the behavioral state of active sleep. It is unclear whether eye movement events contribute to the modulation of trigeminal sensory neuron activity during active sleep. In the present study, eye movement events were demarcated in order to investigate how these events affect peripheral input to trigeminal sensory neurons in chronic, intact, behaving cats. When compared with wakefulness, the mean response of 45 trigeminal sensory neurons to low-intensity electrical stimulation of the canine tooth pulp was significantly suppressed by 28% during periods of active sleep where no eye movement activity was present and by 41% during periods of active sleep with eye movement events. Hence, during active sleep, tooth pulp-evoked responses were significantly decreased by 16% during eye movement events when compared with non-eye movement active sleep. To investigate whether presynaptic inhibition played a role in this phenomenon, the excitability of eight individual tooth pulp afferent terminals during eye movement periods was compared with non-eye movement periods of active sleep. No evidence of eye movement-related depolarization of tooth pulp terminals was detected. When compared to wakefulness, the responses of six trigeminal sensory neurons to air puff stimulation of facial hair mechanoreceptors were significantly increased by 96% during periods of active sleep where no eye movement activity was present but were significantly decreased by 15% during eye movement events when compared with non-eye movement active sleep. The results of the present study indicate that neuronal responses to both tooth pulp and facial hair mechanoreceptor stimulation are significantly attenuated during eye movement events of active sleep.     

Detection of secreted cysticercal antigen: a useful tool in the diagnosis of inflammatory neurocysticercosis

Neurocysticercosis is a common parasitic disease of the human central nervous system. It is particularly prevalent in developing countries, where it has a serious public health and economic impact. A major diagnostic problem with neurocysticercosis is its pleomorphic nature. Conventional diagnosis of neurocysticercosis still requires brain-computed tomography and/or magnetic resonance imaging, which are definitive but often prohibitively expensive and inaccessible in endemic areas. Herein, the monoclonal antibody HP10 antigen-trapping enzyme-linked immunosorbent assay, which has been used successfully to detect viable Taenia solium cysticercosis, was evaluated using cerebrospinal fluid (CSF) from Mexican neurocysticercosis patients with various defined pathologies. Sensitivity was higher in cases of inflammatory compared with non-inflammatory disease (94.1% vs. 33.3%) and in cases of multiple- compared with single-cyst cysticercosis (85% vs. 33.3%). Positivity was a strong indicator of active, inflammatory, multiple-cyst neurocysticercosis detecting 100% (15/15) of such cases. The overall specificity, as determined using CSF samples from patients with other neurological symptoms, was 97.7% (42/43). Since the assay only detects viable infection, it is of known value in the follow-up of treated patients to determine whether treatment has been successful. Thus, antigen detection may be of particular value in the assessment of symptomatic patients, who may potentially benefit from rapid treatment.     

An approach to minimize postoperative enterocolitis in Hirschsprung's disease

Background/Purpose

Enterocolitis (EC) is a common and severe complication after pull-through for Hirschsprung's disease; its pathogenesis remains unclear, but the role of coexistent intestinal neuronal dysplasia (IND) in the proximal colon may be relevant. This study evaluated the relationship between postoperative EC and IND and assessed whether a surgical protocol including resection of coexistent IND could prevent postoperative EC.

Methods

Between June 1993 and June 2002, 36 patients with aganglionosis were submitted to definitive surgical treatment. There were 2 sequential sets of patients: group I (n = 17), in whom the resection was confined to the aganglionic colon, and group II (n = 19), who were additionally submitted to resection of the coexistent IND segment; excision was restricted to the hepatic flexure in long segmental IND. The prevalence of postoperative EC and anorectal function were evaluated and compared between the 2 groups.

Results

There was no mortality. Fifteen patients had isolated aganglionosis, and 21 presented with aganglionosis plus proximal IND. All 6 children who developed postoperative EC had coexistent IND. In group I, 9 patients had coexistent IND and 5 developed postoperative EC (5/17, 29%). In group II, 12 patients had coexistent IND but only 1 patient, with long segmental IND, developed postoperative EC (1/19, 5%). Among the patients with proximal IND, the prevalence of postoperative EC was 29%; but it was significantly lower in group II than in group I (1/12 or 8% vs 5/9 or 56%; P = .02). Anorectal function was excellent or good in more than 80% of the patients in both groups.

Conclusions

Postoperative EC was associated with retained proximal IND, suggesting that coexisting IND may be, at least, a predictive marker for this complication. Histochemical characterization of the proximal colon with no radical resection of the IND segment seems to be an effective and safe approach to minimize the prevalence of postoperative EC.     

Restoration of Spermatogenesis in Dibromochloropropane (DBCP)-Treated Rats by Hormone Suppression

The exposure of men to the nematocide dibromochloropropane (DBCP)has caused prolonged oligo- and azoospermia, which occasionallyreverses spontaneously. We recently demonstrated that in testesof rats treated with a dose of DBCP sufficient to reduce thepercentage of tubules producing differentiating germ cells (tubuledifferentiation index, TDI) to 20%, the tubules lacking differentiatingcells contained type A spermatogonia. To determine whether thesetype A spermatogonia could be stimulated to differentiate, ashad been demonstrated previously in other models of toxicant-inducedsterility, we suppressed intratesticular testosterone and serumfollicle stimulating hormone (FSH) levels with the GnRH agonistLupron (leuprolide). When the GnRH agonist was given for 10weeks starting immediately after DBCP exposure, the TDI wasmaintained at 94%. Even when GnRH-agonist treatment was stoppedat week 10, the TDI remained between 65 and 80% 10 weeks later.Late spermatid counts averaged 10 x 10⁶ per testis for the GnRH-agonist–treatedrats at week 20 compared with 1.7 x 10⁶ per testis in rats treatedwith only DBCP. To determine whether spermatogonial differentiationcould be stimulated after the TDI had declined to below 30%,we initiated GnRH-agonist treatment 6 weeks after DBCP exposure.The GnRH treatment increased the TDI to 53% at week 16. Theseresults indicate that, if the same principles apply to humans,suppression of testosterone may be applied to restore spermatogenesisin men rendered azoospermic by DBCP or other reproductive toxicants.     

Duodenal intubation with secretin stimulus for diagnosis of giardiasis.

The use of secretin to facilitate the demonstration of Giardia lamblia in duodenal juice was studied in children under investigation for chronic diarrhoea. 30 children aged 3 months to 13 years, whose stools were negative for G. lamblia, were studied. G. lamblia was demonstrable in a sample of duodenal juice in 1 of the 30 children before an intravenous injection of secretin (1 or 2 mg/kg), but in 9 of the 30 children after secretin. It is concluded that examination of duodenal juice after secretin stimulus is an effective method of showing giardial infestation.     

Treatment for children with severe aplastic anemia and sickle cell disease in low income countries in Latin America: a report on the recent meetings of the Monza International School of Pediatric Hematology/Oncology (MISPHO): Part III

Treatment of hematologic disorders in low-income countries (LIC) is difficult. This report summarizes treatment of sickle cell disease and aplastic anemia by pediatric hematologists from 15 LIC who participate in the Monza International School of Pediatric Hematology/Oncology (MISPHO). Patients with severe sickle cell disease were treated with low dose hydroxyurea, which safely reduced vaso-occlusive crises. Patients with severe aplastic anemia fared poorly due to lack of availability and high cost of anti-thymocyte globulin and cyclosporine and lack of access to stem cell transplantation. Appropriate therapy was most likely to occur in MISPHO centers with an active twinning program with a center in a high-income country.