Potential gravity-induced deformations of polyacrylamide matrices during gelling were investigated in two different initiator systems based on (i) photopolymerization with 100 microM methylene blue, 1 mM sodium toluene sulfinate (reducer) and 50 microM diphenyliodonium chloride (oxidizer) (photopolymerization) and (ii) chemical polymerization, utilizing the standard persulfate N,N,N',N'-tetramethylethylenediamine. In both systems, it is seen that convective flows are imprinted in the final gel structure above a critical gelling layer thickness, set at ca. 3 mm. In both systems, progressive increments of the solution density, from normodense (density = 1.0) up to isodense with the growing polymer chains (density = 1.3) do not inhibit the appearance of strong convective flows. However, gel inhomogeneities are completely abolished even in 10 mm gelling layers if polymerization is performed in presence of density gradients, notably of sucrose, from 0 to 20%, 0 to 40% and 0 to 60%. Even the shallower gradient (0-20% sucrose) is able to completely abolish convective flows in persulfate-driven polymerization. It is hypothesized that such disturbances are not created by sedimentation of the growing polymer chains in the gravitational field, but are produced by the reaction exothermality, which produces strong buoyancy-driven flows. It is additionally demonstrated that persulfate polymerization is sensitive to oxygen absorbed from the top liquid layers, which should be carefully protected by an overlay of organic solvent. Methylene blue-induced polymerization appears to offer a series of unique advantages over chemical initiation with persulfate.

Acrylic Resins↗

PubMedDate not supplied

Roach's mathematical equations in predicting pathological stage in men with clinically localized prostate cancer.

AIMS AND BACKGROUND: The therapeutic choice in patients with clinically localized prostate cancer depends on preoperative clinical stage. Diagnostic instruments currently available for such an evaluation--considered separately--have not shown enough efficacy. Roach has recently introduced three simple mathematical equations that--on the basis of prostate-specific antigen and the biopsy Gleason score--are aimed at calculating the definitive pathological stage. We retrospectively analyzed our radical prostatectomy data base to assess the accuracy of the equations in predicting the final stage in patients with clinically localized prostate cancer. METHODS STUDY DESIGN: The study included 173 patients who had undergone radical retropubic prostatectomy at our Institution. Patients were divided into 25 groups, depending on preoperative PSA and the biopsy Gleason score. The risk of extracapsular neoplastic growth, seminal vesicle involvement and lymph node involvement was calculated for each group by means of Roach's equations. On the basis of definitive histological examinations, we compared the expected risk to the observed risk. RESULTS: The observed risk fell within the interval of expected risk in 16 of 17 groups (94%) regarding the evaluation of extracapsular growth, in 15 of 17 (88%) regarding the analysis of seminal vesicle involvement, and in 14 of 17 (82%) regarding the evaluation of lymph node involvement. Therefore, the observed event was in agreement with the expected event in 45 of 51 groups (88%). CONCLUSIONS: The equations represent a practical and effective instrument for preoperative clinical staging in patients with localized prostate cancer. By means of these mathematical formulas, one can assess the correct prognosis and--above all--plan the best therapeutic approach.

Aged↗

PubMedDate not supplied

Occult HBV infection and suppression of HCV replication in the early phase of combination therapy for chronic hepatitis C.

BACKGROUND: Occult HBV infection in subjects with chronic hepatitis C is related to more severe disease outcome. It has been suggested that it might reduce sensitivity to antiviral treatment. AIMS: To assess in HBsAg negative subjects with chronic hepatitis C any effect of the presence of HBV genomes in the liver on the early kinetics of HCV-RNA under PEG-IFN plus ribavirin. PATIENTS AND METHODS: Twenty-two anti-HCV and HCV-RNA positive subjects, with biopsy-proven chronic hepatitis C (M/F 15/7; 50 +/- 8.6 years, 16 genotype 1b) were given PEG-IFN alpha 2b 1.0 microg qw plus ribavirin (800 to 1,200 mg daily according to body weight) for an intended 52 week period. Early virological response was assessed over the first 4 weeks of therapy by quantifying HCV-RNA. Occult HBV infection was assessed by testing for HBV-DNA in the liver before therapy. RESULTS: HBV genomes were found in the liver of 7 of 22 (31.4%) patients, unrelated to anti-HBc status. Kinetics of HCV-RNA during the first 4 weeks of antiviral treatment was unaffected by occult HBV infection, both in terms of absolute reduction of viral load and of number of cases with a reduction of > or = 2 log10 on treatment. CONCLUSIONS: Occult HBV infection does not affect the early phase of response to combination therapy. Further follow-up of patients into the maintenance phase of antiviral treatment and after stopping it will clarify if and when occult HBV has a role in reducing sustained virological response.

Adult↗

PubMedDate not supplied

[Treatment of biliary stenosis with expandable metallic prostheses].

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Bile Duct Diseases↗

PubMedDate not supplied

[Bacterial isolation in infants hospitalized for acute diarrhea].

Bacteria were investigated in stools of 156 children under two years of age admitted to the pediatric wards of a general hospital at the western metropolitan area of Santiago, Chile, because of acute diarrhea with only one stool sample. A known pathogenic agent was isolated from 115 cases (73.7%), this being a bacteria in 87/115 (75.6%). Most prevalent microorganisms were Enteropathogenic Escherichia coli (EPEC). (65.5%), specially serogroups 0111, 0119 and 055, Enterotoxigenic Escherichia coli (ETEC) (18.4%), Campylobacter yeyuni (13.8%), Salmonellae (9.2%) and Shigellae (6.9%). Invasive Escherichia coli (EIEC) and Aeromonas hydrophila were observed in only one case. Yersinia enterocolitica was not isolated. Age was under one year in 92% of patients and 83% were normally or slightly under nourished. Fecal leucocytes were abnormally increased (greater than 5 per high power field) in 41.4% of positive bacterial isolates, in 83% of children with Shigellae, in 50% of those with EPEC and Salmonellae and in 25% of the Campylobacter yeyuni group.

Acute Disease↗

PubMedDate not supplied

[Current microbiology of oro-maxillofacial infections].

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Abscess↗

PubMedDate not supplied

On-site colposcopy services in a family practice residency clinic: impact on physician test-ordering behavior, patient compliance, and practice revenue generation.

BACKGROUND: Using colposcopy as a model, we examined the impact of introducing a new diagnostic technology into the ambulatory primary care setting. METHODS: Records of patients with abnormal findings on Papanicolaou smears were reviewed from three study periods: 1 year before, 1 year after, and 5 years after initiation of on-site colposcopy services. Data analyzed include physician management decisions, site of colposcopic service, and patient compliance. Practice revenue estimates were based upon patterns of physician management and patient compliance found during each study period. RESULTS: Management of low-grade squamous intraepithelial lesions varied during each study period. By period 3, however, most patients were undergoing colposcopy (P = 0.03). High-grade squamous intraepithelial lesions were uniformly managed with colposcopy during all study periods (P < 0.001). Introduction of on-site colposcopic services resulted in a rapid shift to the on-site location for evaluation of low-grade squamous intraepithelial lesions and a more gradual shift to the on-site location for evaluation of high-grade squamous intraepithelial lesions. Patient compliance was not affected by the introduction of on-site services. On-site colposcopy resulted in a nearly 100 percent transfer of revenue to the practice, but the economic benefit was quite modest. CONCLUSIONS: Although offering on-site colposcopy services might have had some impact on physician management of low-grade squamous intraepithelial lesions, the lack of benefit regarding patient compliance, the relatively small patient volume for this procedure, and its modest impact on practice revenue cause us to question the value of including colposcopy in everyday practice.

Adult↗