Leakage of 4 resin-based root-canal sealers used with a single-cone technique.

OBJECTIVE: The aim of this study was to measure leakage of 4 resin-based sealers. STUDY DESIGN: Four groups of premolars (n = 60) were prepared using GT Rotary files and the crown-down technique and filled by the single-cone technique with AH26, AHPlus, EndoREZ, and an experimental MBP as sealer. Leakage was measured using the fluid filtration method after 15, 30, and 60 days and determined as microL/min(-1) x 10 psi. RESULTS: Statistical analysis by ANOVA and Tukey HSD test indicated that root fillings with AH Plus and the MBP showed lower leakage values after 15 days (P < .05). At 30 days, AH26 presented higher leakage values when compared to other sealers (P < .05). At 60 days, MBP and AH Plus presented the lower leakage values, differing significantly from EndoREZ (P < .05). CONCLUSION: It was observed that AH Plus and the experimental MBP showed lower leakage after 60 days than AH 26 and EndoREZ.     

Skin cancers and precancerous lesions in Parkinson's disease patients.

Our objective was to evaluate the frequency of neoplastic and preneoplastic skin lesions in Parkinson's disease (PD) patients when compared with an aged-matched population. We performed a cross-sectional survey in PD patients and in an age-matched control group. Patients and controls were examined by a movement disorder specialist and a dermatologist. 150 PD patients and 146 controls were included. Thirty-five PD patients (23.3%) presented skin lesions that could be classified as neoplastic or preneoplastic vs. 20 subjects in the control group (13.7%) (OR 95%, CI 1.92 [1.05, 3.51]). However, this difference lost statistical significance when adjusted for gender (recruitment of controls was matched just for age with an over representation of males in the PD group). Twenty-nine PD patients (19%) presented actinic keratosis and basal cell carcinoma was diagnosed in 4 patients (3%). Although nonconclusive, our results are in agreement with previous studies suggesting an increased risk of skin cancer in PD patients. The frequency of actinic keratosis in PD patients and the associated risk to develop melanoma recommends its screening in future epidemiological studies.     

THE IMPACT OF PRE-CLERKING CLINICS ON SURGICAL OPERATION CANCELLATIONS: A PROSPECTIVE AUDIT

Pre-clerking of all patients undergoing elective general surgical operations was introduced at our hospital in an attempt to reduce an unacceptably high operation cancellation rate. A prospective audit has been performed on the effect of this policy on the cancellation rate. Before the introduction of pre-clerking there was a marked seasonal variation in the number of patients who failed to attend for surgery, which could be explained by absence on holiday. This seasonal variation disappeared after the start of pre-clerking clinics, but there has been no reduction in the number of cancellations for medical reasons.     

Serum lipids levels and some risk factors of cardiovascular diseases in a population of the municipality of S?o Paulo, SP (Brazil)

An attempt was made to characterize lipemic levels according to sex, age and presence or absence of cardiovascular disease risk factors, in a population of 3,792 people between the ages of 20 and 59, in terms of smoking habits, obesity, family history of diabetes and use of oral contraceptives. Those individuals who did not present any of the risk factors mentioned were classified as "exempt". After submitting the data to variance analysis it was found that: for men between 20 and 49 years of age there were high significant differences in the averages obtained for the seric levels of total lipids, triglycerides and total cholesterol between "exempt" and obese and "exempt" and obese with a family history of diabetes; for the 50 to 59 age group there were significant differences in the average of the values corresponding to the seric levels of total lipids between "exempt" and those individuals in whom obesity appeared associated with smoking habits or associated with a family history of diabetes. The averages obtained for seric triglycerides were significantly different between "exempt" and non-obese with a family history of diabetes, obese, obese smokers and obese with a family history of diabetes. On the other hand, the averages relating to seric levels of total cholesterol were different, at significant levels, between "exempt" and obese smokers; the risk represented by the smoking habit showed no relevance with regard to the lipemic levels in any group except for that of men between 30 and 39 years of age. In their case, there were significant differences between the averages obtained for the seric levels of total lipids, triglycerides and total cholesterol, between "exempt" and smokers and between "exempt" and obese smokers. It is to be noted that the differences obtained with regard to the averages relating to lipemic levels as between "exempt" and obese were less those obtained between "exempt" and obese smokers, thus showing the possible relevance of the risk presented by the smoking habit; -- among the women there were less accentuated differences in the averages corresponding to the lipemic levels as between "exempt" and those who presented one or more risk factors. Thus, for the age group from 20 to 29 there were significant differences in the averages obtained for total lipids as between "exempt" and obese.(ABSTRACT TRUNCATED AT 400 WORDS)     

Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability

X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene. Disease-associated alleles (37-66 CAGs) change in length when transmitted from parents to offspring, with a significantly greater tendency to shift size when inherited paternally. As transgenic mice carrying human AR cDNAs with 45 and 66 CAG repeats do not display repeat instability, we attempted to model trinucleotide repeat instability by generating transgenic mice with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions in their genomic context. Studies of independent lines of AR YAC transgenic mice with CAG 45 alleles reveal intergenerational instability at an overall rate of approximately 10%. We also find that the 45 CAG repeat tracts are significantly more unstable with maternal transmission and as the transmitting mother ages. Of all the CAG/CTG repeat transgenic mice produced to date the AR YAC CAG 45 mice are unstable with the smallest trinucleotide repeat mutations, suggesting that the length threshold for repeat instability in the mouse may be lowered by including the appropriate flanking human DNA sequences. By sequence-tagged site content analysis and long range mapping we determined that one unstable transgenic line has integrated an approximately 70 kb segment of the AR locus due to fragmentation of the AR YAC. Identification of the cis - acting elements that permit CAG tract instability and the trans -acting factors that modulate repeat instability in the AR YAC CAG 45 mice may provide insights into the molecular basis of trinucleotide repeat instability in humans.      

Atropine and hexamethonium-sensitive,Ca/K-modulated,reversible swelling of mast cells in rat mesentery,due to feeding or exposure to carbachol

Transitory swelling of mesenteric mast cells was observed when 24 h-fasted rats were given access to food. Atropine, an anti-muscarinic drug given (1 mg/kg, i.p.) 60 min prior to feeding, prevented this response; carbachol, a cholinomimetic drug caused it to occur when given (2 g/kg, i.v., 10 min) to fasted rats. Mast cells in the mesentery excised from fasted rats, presented swellingin vitro within 1 min following exposure to 10^–7 M carbachol. This response was inhibited by atropine (10^–8 M) or hexamethonium (10^–8 M), indicating that stimulation of a parasympathetic nerve pathway, reported to exist in rat mesentery, could induce mast cell swelling. Exposure to a Ca²⁺ free medium also led to rapid swelling of mast cells in the mesentery excised from fasted rats. This result, as well as inhibition of the mast cell response to carbachol caused by increasing the Ca²⁺ (but not by increasing the Mg²⁺) content of the incubation medium, suggests that swelling was caused by a sudden decrease of Ca at mast cell membrane sites controlling ion/water fluxes. Mast cells swollen by feeding, carbachol, or Calack, reverted to their original condition within 20 min when incubated in balanced salt buffer. Such reversal did not occur in a KCl-enriched medium. An equivalent (in terms of ionic, strength), increase in NaCl, did not reproduce this effect, indicating that mast cells have K⁺-dependent means of compensating for endogenously or drug-induced volume changes. Swelling caused by cholinergic stimulation of mast cells was not accompanied by granule exocytosis. The, implication of these findings, as well as of the kininogen decrease previously reported to occur in carbachol-treated rat bloodin vivo orin vitro, is discussed in terms of putative mast cell-controlled, localized homeostasis in the rat mesentery.     

Chain conformation and compatibility in polymer blends. A small-angle X-ray scattering study of the system poly(propylene glycol)-poly(methyl methacrylate)

The thermodynamic compatibility of dilute, solid solutions of poly(propylene glycol) (PPG) (mass-average molar mass M?_w = 3900 g/mol) in poly(methyl methacrylate) (PMMA) (M?_w = 550000 g/mol) was investigated by means of small-angle X-ray scattering. The results of the analysis show that PPG is molecularly dispersed in the solid, amorphous matrix of PMMA, and that the molecules display the typical statistical coil macroconformation of polymers in dilute, liquid solution, whereby the numerical value of the second virial coefficient seems to point to the unperturbed nature of the coils. This behaviour, consistent with the concept of “interpenetration of segments”, is in total agreement with the experimentally measured compositional variation of the glass transition temperature of the blends.     

Production of type II heat-labile enterotoxin by Escherichia coli isolated from food and human feces.

Escherichia coli strains isolated in Sao Paulo, Brazil, from feces of patients with diarrhea and from food samples produced toxin(s) that was shown to be related both immunologically and genetically to the recently characterized type II heat-labile enterotoxin of E. coli. The new isolates of type II heat-labile enterotoxin-producing E. coli belonged to five different serotypes and did not represent a single clone.     

CD40 is required for the optimal induction of protective immunity to Mycobacterium avium

C57Bl/6 mice and mice deficient in the CD40 molecule were infected with three strains of Mycobacterium avium. Two of the M. avium strains proliferated more extensively in CD40-deficient (CD40-/-) mice than in control mice. The increased susceptibility to infection of CD40-/- mice was associated with the generation of poorer interleukin-12 (IL-12) p40 and interferon-gamma (IFN-gamma) responses as compared to the controls, suggesting a role for CD40 in the development of protective immunity. In contrast, direct triggering of CD40 on infected macrophages failed to induce any anti-mycobacterial activity in infected macrophages.