Influence of cold working on fatigue behavior of stainless steels used for prothesis: application to the study of wires with small sections.

Orthodontists mainly use stainless austenitic wires with a wide range of ultimate tensile strength. To characterize the dynamical behavior of these wires, the authors have perfected machines to test materials with their original surface roughness without any prior machining of surfaces. Fatigue limits are discussed through mechanical and structural properties of the austenitic steels, with special attention given to cold working. Typical features of fracture, and particularly of the first cracks, are shown by means of scanning electron microscopy.     

Pefloxacin: evolution of in vitro activity during 18 months of use in an intensive care unit

The MIC of pefloxacin against all the strains (3122) isolated in an intensive care unit during 18 months was studied. The MIC of pefloxacin was estimated by standard agar diffusion method in Mueller-Hinton agar. All the strains with a MIC lower than 2 mg/l were considered as sensitive, between 2 and 4 mg/l as "intermediary" and over 4 mg/l as resistant. Geometrical means of MICs were calculated for each month and for different species. The study continued for 18 months from the introduction of the drug which was in widespread and constant use as a first-choice antibiotic. No significant increase was detected in the incidence of resistant strains during the study; on the other hand, small, limited clusters of resistant strains were observed during minor nosocomial epidemics. The general features of quinolone activity, the spectrum of this new quinolone and the slow evolution of the bacterial population are discussed.     

Acetylcholine receptor antibody as a diagnostic test for myasthenia gravis: results in 153 validated cases and 2967 diagnostic assays.

Anti-acetylcholine receptor (AChR) antibody was undetectable in 26/153 (17%) sera from myasthenia gravis patients assayed by standard RIA using human acetylcholine receptor. Eight of these were found to be positive with a modified protocol using a mixture of normal and denervated AChR, reducing the proportion of "negative" sera to 12%. Many of these were from patients with a short history; two such patients later developed low positive values. Anti-AChR without clinical evidence of myasthenia was found in one of three monozygotic twins of myasthenia gravis patients, and in one of thirty other first degree relatives of a further 17 patients. Anti-AChR is a valuable and highly specific diagnostic test which, with the assay used here, is positive in about 88% of patients with clinical features of myasthenia gravis.     

Resorbable suture support for ventricular aneurysmectomy

The edge of tissue left after ventricular aneurysmectomy requires very careful placement and tying of the sutures. The use of Teflon felt as a support appears to redistribute the pressure and thus prevent the sutures from cutting through the vulnerable tissue. In many cases, Teflon felt reinforcement is preferred to direct unsupported closure because of perioperative of immediately postoperative bleeding complications. However, the unavoidable full immobilization of the sutured area, the possible risk of foreign body infection, and the extensive adhesions and calcification in the long term compelled us to search for a better alternative, combining the convenience of both methods and limiting the risks. PDS (polydioxine) resorbable pledgets and strips, provided by Ethicon GmbH, were used as a suture support during the past 2 years for closure of 29 ventricular aneurysmectomies and four ischemic ventricular septal defects, all except one in combination with coronary bypass grafting. The PDS material was easy and efficient to apply and caused no complications during and after the operation. In one case, we had the opportunity to review the supported scar during a second operation for new coronary grafts after 18 months. The formerly feared "linear scar petrification," usual after use of Teflon felt, was absent. The scar was free from difficult adhesions. Our initial experience suggests the further extensive use of this resorbable material as a support for various sutures at risk.     

A clinical, demographic and microbiologic study of ANUG patients in an urban dental school

35 ANUG patients were examined and compared clinically and demographically. Plaque removed from ulcerated sites in 20 patients was cultured using quantitative anaerobic procedures and examined by electron and darkfield microscopy. Patients were classified as having ANUG when presenting with ulceration and necrosis of interproximal papillae, pain and bleeding. The clinical symptoms of fetid odor, pseudomembrane formation, lymphadenopathy and elevated body temperature were present in 97%, 85%, 61% and 39% of the ANUG patients, respectively. 83% of the patients were smokers. The ANUG patients demonstrated a lower average age (24 years) than the general clinic population (32 years). There was a slightly higher % of male (54%) than female (46%) and the % of Caucasian (51%) and black (49%) ANUG patients were almost equal. Cultural studies revealed that gram-negative rods were the predominant cultivable micro-organisms present in the plaque, representing 78.2% of the total recoverable count. Of these, nearly half were strict anaerobes with Bacteroides gingivalis and Fusobacterium nucleatum accounting for 7.8% and 3.4%, respectively. Anaerobic and facultative gram-positive cocci (15.5%), gram-negative cocci (3.5%) and gram-positive rods (2.8%) were also isolated. Microscopic analysis of the morphologic composition of plaque revealed that rods (43%) constituted the greatest % of the total microorganisms observed followed by spirochetes (30%) and cocci (27%). 8 distinct types of spirochetal periplasmic flagellar arrangement were observed by electron microscopy, the "2-4-2" periplasmic flagellar arrangement being most numerous.     

Traumatic aneurysms of the descending thoracic aorta

From July 1979 to December 1985 we observed 51 patients with traumatic lesions of the descending thoracic aorta. Twenty-nine had acute ruptures, mostly accompanied by multiple injuries, and 27 had to be operated upon immediately. Twenty-two patients (19 males, 3 females) had chronic traumatic aneurysms of the descending thoracic aorta (more than six weeks after trauma). Mean age at the time of trauma was 24 years. Mean age at time of surgery was 36.5 years. Twelve patients were symptomatic. All were treated surgically. At surgery, complete aortic disruption was found in 15 patients and partial rupture in seven. We did not use aortic shunting of any kind, only aortic cross-clamping. Hypertension was controlled by intravenous drug infusion. The ruptured aortic segment was replaced in all cases by prosthetic Dacron graft. There were no operative deaths. One patient (age 77) died 11 weeks after surgery from multiple organ failure. One case of postoperative paraplegia was observed. This patient recovered almost completely from his neurological deficit.     

Treatment of malignant gliomas in adults with BCNU plus metronidazole

Summary Twenty-six adult patients with astrocytomas were treated with BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea) 180–240 mg/m² 1.V. every 6–9 weeks, with metronidazole 1.5 g/m² p. o. 12 h and 1 h before BCNU and again 6 h and 24 h after BCNU. Of twenty-two evaluable patients, 9 (41%) responded with evidence of reduced tumor size on CT scan, 3 (14%) stabilized and 10 (45%) failed. Patients with no prior chemotherapy or radiotherapy, good performance. status, low grade tumors, and age 50 years had the highest response rates, although differences were not statistically significant. Median survival and duration of response have not been reached with a median follow-up time of ten months. Hematological toxicity was dose-limiting and was probably not augmented by the metronidazole. There was one death from infection that was possibly drug-related. Gastrointestinal toxicity was substantial, and was probably increased by the metronidazole.While the combination of BCNU and metronidazole were tolerable, the response rate seen was no higher than that noted for BCNU alone, and further studies using this dose-schedule are not recommended in astrocytomas.Presented at the 13th International Congress of Chemotherapy, Vienna Austria, August 1983.     

Systematic review of accelerometer-based methods for 24-h physical behavior assessment in young children (0–5 years old)

Background

Accurate accelerometer-based methods are required for assessment of 24-h physical behavior in young children. We aimed to summarize evidence on measurement properties of accelerometer-based methods for assessing 24-h physical behavior in young children.

Methods

We searched PubMed (MEDLINE) up to June 2021 for studies evaluating reliability or validity of accelerometer-based methods for assessing physical activity (PA), sedentary behavior (SB), or sleep in 0–5-year-olds. Studies using a subjective comparison measure or an accelerometer-based device that did not directly output time series data were excluded. We developed a Checklist for Assessing the Methodological Quality of studies using Accelerometer-based Methods (CAMQAM) inspired by COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN).

Results

Sixty-two studies were included, examining conventional cut-point-based methods or multi-parameter methods. For infants (0—12 months), several multi-parameter methods proved valid for classifying SB and PA. From three months of age, methods were valid for identifying sleep. In toddlers (1—3 years), cut-points appeared valid for distinguishing SB and light PA (LPA) from moderate-to-vigorous PA (MVPA). One multi-parameter method distinguished toddler specific SB. For sleep, no studies were found in toddlers. In preschoolers (3—5 years), valid hip and wrist cut-points for assessing SB, LPA, MVPA, and wrist cut-points for sleep were identified. Several multi-parameter methods proved valid for identifying SB, LPA, and MVPA, and sleep.

Despite promising results of multi-parameter methods, few models were open-source. While most studies used a single device or axis to measure physical behavior, more promising results were found when combining data derived from different sensor placements or multiple axes.

Conclusions

Up to age three, valid cut-points to assess 24-h physical behavior were lacking, while multi-parameter methods proved valid for distinguishing some waking behaviors. For preschoolers, valid cut-points and algorithms were identified for all physical behaviors. Overall, we recommend more high-quality studies evaluating 24-h accelerometer data from multiple sensor placements and axes for physical behavior assessment. Standardized protocols focusing on including well-defined physical behaviors in different settings representative for children’s developmental stage are required. Using our CAMQAM checklist may further improve methodological study quality.

PROSPERO Registration number

CRD42020184751.

     

The Liver Retransplantation Risk Score: a prognostic model for survival after adult liver retransplantation

High-risk combinations of recipient and graft characteristics are poorly defined for liver retransplantation (reLT) in the current era. We aimed to develop a risk model for survival after reLT using data from the European Liver Transplantation Registry, followed by internal and external validation. From 2006 to 2016, 85 067 liver transplants were recorded, including 5581 reLTs (6.6%). The final model included seven predictors of graft survival: recipient age, model for end-stage liver disease score, indication for reLT, recipient hospitalization, time between primary liver transplantation and reLT, donor age, and cold ischemia time. By assigning points to each variable in proportion to their hazard ratio, a simplified risk score was created ranging 0–10. Low-risk (0–3), medium-risk (4–5), and high-risk (6–10) groups were identified with significantly different 5-year survival rates ranging 56.9% (95% CI 52.8–60.7%), 46.3% (95% CI 41.1–51.4%), and 32.1% (95% CI 23.5–41.0%), respectively (P < 0.001). External validation showed that the expected survival rates were closely aligned with the observed mortality probabilities. The Retransplantation Risk Score identifies high-risk combinations of recipient- and graft-related factors prognostic for long-term graft survival after reLT. This tool may serve as a guidance for clinical decision-making on liver acceptance for reLT.