Response of the unattached 218Po activity size distribution in H2O-SO2-N2 atmospheres.

The response of the unattached 218Po activity size distribution to variations in H2O and SO2 concentration was investigated in a high-purity N2 atmosphere. Lognormal size distributions were reconstructed from screen diffusion battery data using a random search and optimization procedure. For relative humidities of 1% to 90%, SO2 concentrations of 0-6 ppm, and residence times of 38 s, median diameters of the unattached mode ranged from 0.50 (+/- 0.04) to 0.80 (+/- 0.06) nm, corresponding to diffusion coefficients of 0.1-0.05 cm2 s-1. Increases in water vapor concentration resulted in an enhanced rate of ion neutralization and suppression of ion cluster formation. Decreases in cluster diameter with increasing humidity were therefore observed. Addition of SO2 at constant relative humidity resulted in an initial increase in diameter, with a subsequent decrease. Geometric standard deviations averaged 1.05 (+/- 0.01) to 1.06 (+/- 0.01) in all cases, with the unattached fraction comprising 83% to 88% of the total distribution. Results suggest that increases in water vapor concentration enhance neutralization in the immediate vicinity of the recoil path through water radiolysis. Conversion of OH to H2OSO4 on addition of SO2 provides a binary condensable phase capable of clustering around the ion at low relative humidities, increasing particle size. High H2O and SO2 concentrations enhance neutralization through electron scavenging and subsequent ion collision near the end of the recoil path, decreasing the number of available cluster sites and suppressing cluster formation. This reduction is more significant than the increasing size of the stable ion cluster, with increasing H2O and H2SO4 concentrations as predicted by Raes, resulting in decreases in both median diameter and distribution spread.     

The importance of intraoperative cholangiography during laparoscopic cholecystectomy

Laparoscopic cholecystectomy (LC) using electrocoagulation was successfully performed in 56 out of 58 selected patients. Cholangiography was performed in 53 patients. Six patients had common duct stones; five were unsuspected preoperatively. After the gallbladder was removed, three patients underwent open common duct exploration. In another five cases, anatomical anomalies were discovered. Cholangiography performed via the cystic duct before any structures are divided can prevent the most serious complication--common duct injury. Cholangiography should be attempted on all patients undergoing LC.     

Retrospective multicenter analysis of 3i endosseous dental implants placed over a five‐year period

Osseointegrated dental implants have now become an accepted form of treatment for patients with a fully or partially missing dentition. The purpose of this study was to evaluate the performance of 3i threaded and cylindrical implants. During a 5-year period, a total of 1969 3i endosseous implants were placed at 6 centers in the United States and 2 elsewhere in the edentulous and partially edentulous jaws of 653 consecutive patients ranging in age from 18 to 82 years. Of the total number of implants placed, 1341 were commercially pure titanium threaded implants and 628 were titanium plasma-sprayed implants with a cylindrical configuration. A total of 28 patients with 110 implants were lost to follow-up. Implants in these patients were considered neither a success nor a failure. Success was predicated on the osseointegration of each and every implant followed in this analysis rather than the persistence of prosthetic function. Confirmed bone anchorage was considered essential for success. A total of 625 patients with 1871 implants remain in the study with a follow-up period ranging from 6 to 60 months. A total of 93 implants (5.0% of the total implants followed) were considered as failures. A mean implant survival rate was 95.0% for both the threaded and the cylindrical implant was calculated. The success rate of threaded implants was 97.0% in the mandible and 93.8% in the maxilla. The success rate for the 3.3mm cylindrical implants was 96.0% in the mandible and 95.5% in the maxilla, and the success rate of 4.0mm diameter cylindrical implants was 95% in the mandible and 92.0% in the maxilla. Causes of failure consisted of loss of osseointegration 2.3%crestal bone loss requiring periodontal therapy after the first year of function 1.7% and mechanical problems associated with the prosthesis 0.9%. This retrospective analysis of the 3i endosseous implant system is comparable to previous reports on other implant systems in terms of implant survival and prosthesis stability. It is demonstrated that 3i implants are predictable and can provide lasting osseointegration leading to improvement of oral function if the recommended surgical and restorative protocol is followed.     

Attitudes and behaviors of African-American and Mexican-American women delivering newborns in inner-city Los Angeles.

To study some of the factors relating to the care of mothers and newborns in an inner-city hospital, three sources of information were reviewed: an obstetric database including information on prenatal care and perinatal mortality, a database of all admissions to the hospital neonatal intensive care unit over the past 5 years, and a detailed questionnaire concerning attitudes and behaviors of recently delivered women. While analyses from these hospital-based data are not conclusive, the results add evidence for the following propositions: 1) Optimal prenatal care is infrequently obtained by mothers delivering at inner-city hospitals. Lack of prenatal care is clearly associated with increased perinatal mortality. While the need for prenatal care is appreciated by 98% of the mothers in this sample, the most frequent reasons why prenatal care is not obtained earlier or more frequently involve knowledge about and access to prenatal care. 2) Inner-city mothers, in general, manifest attitudes and behaviors that promote the welfare of their pregnancies and newborns. These attitudes and behaviors are in stark contrast to those that are frequently attributed to inner-city women by the media. 3) Acute perinatal medical and nursing care are perceived by many postpartum women as suboptimal, particularly in terms of the lack of respect shown to patients by nurses and doctors. 4) Improved acute obstetric and neonatal care improves perinatal morbidity and mortality of infants delivered at inner-city hospitals.     

Symmetrical interdigital keratoderma of the hands

We report the case of a 26-year-old man affected by a symmetrical keratoderma localized to the interdigital spaces of the fingers. No occupational, traumatic, or irritant factors were discovered. Clinical and histological features were consistent with the diagnosis of symmetrical interdigital hyperkeratosis, a sporadic disorder described by Frei in 1926. We believe this condition to be less rare than the few cases reported in the literature would suggest.     

VASOCONSTRICTOR RESPONSES TO COMPONENTS OF THE RENIN-ANGIOTENSIN SYSTEM IN CYCLOSPORIN-INDUCED HYPERTENSION IN THE RAT

1. Since plasma renin activity is increased in cyclosporin A (CsA)-induced hypertension in the rat, the role of the vascular renin-angiotensin system (RAS) in CsA-induced hypertension was investigated in rat mesenteric resistance vessels. 2. Female Wistar rats received CsA (10 mg/kg per day, s.c.) or vehicle for 30 days. CsA treatment increased tail-cuff systolic blood pressure (CsA treated 135 ± 3 mmHg vs control 125 ± 1 mmHg, P<0.0001). 3. Mesenteric resistance arteries (200–300 μm) were isolated and mounted in a microvessel myograph. Concentration-response curves to tetradecapeptide renin substrate (10-¹¹-10^?6 mol/L), angiotensin I (10-^l1-10^?6 mol/L) and angiotensin II (10-¹²-10^?6 mol/L) showed no differences between CsA-treated and control groups. 4. Mesenteric vascular angiotensin-converting enzyme (ACE) characteristics were determined by radioligand binding. There were no differences in the content or affinity of ACE between CsA-treated and control rats. 5. These results suggest that the mesenteric vascular RAS does not play a major role in CsA-induced hypertension in the rat.