Transmission of infection from non-isolated patients with COVID-19 to healthcare workers.

Insufficiently protected healthcare workers (HCWs), defined as high-risk contacts of patients with coronavirus disease 2019 (COVID-19), are routinely quarantined. This study evaluated the transmission of infection from a symptomatic patient with COVID-19 to 60 HCWs exposed at ≤2 m for ≥15 min or during aerosol-generating procedures. Following ≥106 unique high-risk contacts, none of the HCWs tested positive for severe acute respiratory syndrome coronavirus-2 RNA or developed antibodies. The HCWs reported adherence to basic infection control procedures. These results are in accordance with other reports, and should reassure HCWs and further stimulate broader evaluation of the foundation for the current practice of home quarantining non-symptomatic HCWs.

Multicentre study of multidisciplinary team assessment of pancreatic cancer resectability and treatment allocation.

BACKGROUND: Multidisciplinary team (MDT) meetings have been adopted widely to ensure optimal treatment for patients with cancer. Agreements in tumour staging, resectability assessments and treatment allocation between different MDTs were assessed. METHODS: Of all patients referred to one hospital, 19 patients considered to have non-metastatic pancreatic cancer for evaluation were selected randomly for a multicentre study of MDT decisions in seven units across Northern Europe. Anonymized clinical information and radiological images were disseminated to the MDTs. All patients were reviewed by the MDTs for radiological T, N and M category, resectability assessment and treatment allocation. Each MDT was blinded to the decisions of other teams. Agreements were expressed as raw percentages and Krippendorff's α values, both with 95 per cent confidence intervals. RESULTS: A total of 132 evaluations in 19 patients were carried out by the seven MDTs (1 evaluation was excluded owing to technical problems). The level of agreement for T, N and M categories ranged from moderate to near perfect (46·8, 61·1 and 82·8 per cent respectively), but there was substantial variation in assessment of resectability; seven patients were considered to be resectable by one MDT but unresectable by another. The MDTs all agreed on either a curative or palliative strategy in less than half of the patients (9 of 19). Only fair agreement in treatment allocation was observed (Krippendorff's α 0·31, 95 per cent c.i. 0·16 to 0·45). There was a high level of agreement in treatment allocation where resectability assessments were concordant. CONCLUSION: Considerable disparities in MDT evaluations of patients with pancreatic cancer exist, including substantial variation in resectability assessments.

Sigmoidostomy-related parastomal hernia.

BACKGROUND AND AIMS: The aim was to examine prevalence and treatment of parastomal hernias in patients with sigmoidostomy. MATERIALS AND METHODS: In 2009, the medical records of 447 consecutive patients operated with a sigmoidostomy from January 1999 to December 2008 were retrospectiely reviewed. 119 dead patients (26.6%) were excluded because of short follow up (n = 59) and insufficient clinical data (n = 60). 328 patients (73.4%) were followed-up, of whom 210 (64%) alive patients also were scrutinized for presence of parastomal hernia by phone interview. In 2010, 92 out of 153 alive patients (60.1%) without known parastomal hernia also underwent targeted clinical examination in the ambulatory unit. RESULTS AND CONCLUSION: Follow up from stoma operation in 328 patients was median 20 (range 1-129) months. 319 patients had an end sigmoidostomy and nine patients had a loop sigmoidostomy. Time to parastomal hernia in 66 patients (20.1%) was median 9 (1-54) months. Fourty four patients (66.7%) reported no symptoms, eight (12.1%) had mild discomfort, six (9.1%) leakage, six (9.1%) pain, and two (3%) episodes of intestinal obstruction. Eleven (16.7%) had a hernia operation, eight with onlay mesh repair complicated with bowel perforation and ventral hernia in one patient. Three with mesh repair (37.5%) developed recurrent parastomal hernia, of whom one had tissue repair and a second recurrence 6 months later. The only patient with initial tissue repair had a recurrent hernia successfully treated with mesh repair. Two patients had their stoma uneventfully reversed. Parastomal hernia rate, mainly treated with mesh repair, was fairly low in this heterogenous patient series.

In vitro testing of the deformation pattern and initial stability of a cementless stem coupled to an experimental femoral head, with increased offset and altered femoral neck angles.

The ability to vary femoral offset and neck angles in total hip arthroplasty increases the amount of flexibility in the mechanical reconstruction of the hip joint. The present study investigates the changes in strain pattern and bone-implant micromotion caused by increased femoral offset in combination with retroversion or reduced neck-shaft angle, made possible by a large experimental femoral head. A cementless femoral stem was inserted in 10 human cadaver femurs. Three femoral head configurations were tested: the standard situation, an increased offset combined with retroversion, and increased offset combined with reduced neck-shaft angle. The femurs were loaded in a hip simulator that was able to reproduce the conditions that correspond to one-legged stance and stair climbing. There was a statistically significant increase in strain for the experimental head at several strain gauge rosettes compared to the standard head. The largest significant increase in strain was 14.2 per cent on the anterior side of the femur. The largest mean total point motion was 44 microm in the distal coating area for the configuration with increased femoral offset and retroverted neck axis. The clinical relevance of the changes in strain distribution is uncertain. The femoral stem showed excellent initial stability for all test situations.

Increased strain in the femoral neck following insertion of a resurfacing femoral prosthesis.

The cortical strains on the femoral neck and proximal femur were measured before and after implantation of a resurfacing femoral component in 13 femurs from human cadavers. These were loaded into a hip simulator for single-leg stance and stair-climbing. After resurfacing, the mean tensile strain increased by 15% (95% confidence interval (CI) 6 to 24, p = 0.003) on the lateral femoral neck and the mean compressive strain increased by 11% (95% CI 5 to 17, p = 0.002) on the medial femoral neck during stimulation of single-leg stance. On the proximal femur the deformation pattern remained similar to that of the unoperated femurs. The small increase of strains in the neck area alone would probably not be sufficient to cause fracture of the neck However, with patient-related and surgical factors these strain changes may contribute to the risk of early periprosthetic fracture.

Steady-state solution of a two-species biofilm problem.

Through a thorough investigation of the boundary conditions for a general two-species biofilm model, a simple and fast method for solving the steady-state case is developed and presented. The methods used may be extended to biofilm models in which more than two species are considered. Four different sets of boundary conditions are possible for the two-species biofilm model. Each set is shown to be asymptotically stable. A biofilm model describing the competition between autotrophic and heterotrophic bacteria and a biofilm model considering only Nitrosomonas and Nitrobacter are used for illustration. A parameter L(crit), critical film thickness for bacterial coexistence, is introduced from which criteria on the bulk concentrations for coexistence are derived. From these criteria it is seen that the thinner the biofilm, the more restrictive the conditions are for steady-state coexistence. For thin biofilms there may, in many cases, be no point in considering more than one species in the biofilm model. Furthermore, the gradients of the bacterial concentrations are in many cases negligible in thin biofilms, and the biofilm may then be assumed to be homogeneous. The criteria on the bulk concentrations together with the four sets of boundary conditions provide the necessary information for a direct solution of the steady-state two-species biofilm model by means of an ordinary differential and algebraic equation solver.

Proteoglycan metabolism in normal and inflammatory human macrophages.

To study proteoglycan metabolism in inflammatory macrophages, primary cultures of human macrophages were cultured in the absence and presence of bacterial lipopolysaccharide (LPS). When exposed to [35S]sulfate, the cells incorporated the label almost exclusively into chondroitin sulfate proteoglycan (CSPG), which was recovered from the culture medium and the cell layer. Cells stimulated with LPS secreted approximately three times more [35]CSPG into the culture medium than control cells. Furthermore, cell adhesion was also found to promote proteoglycan secretion; when nonadherent monocytic cells were induced to adhere, the release of proteoglycan increased two times. The increased secretion seen in LPS-stimulated macrophages was partly due to increased biosynthesis, but was mostly due to increased sorting of CSPG to the secretory pathway. Only about 20% of the CSPG synthesized in unstimulated cells was secreted, whereas the corresponding figure in LPS-treated cells was 35%. In both cell types, the remaining [35S]CSPG was degraded, probably in the lysosomes. The degradation was a two-step process. First, the [35S]CSPG was rapidly cleaved to yield free glycosaminoglycan (GAG) chains (t1/2 = 15 to 30 minutes). Secondly, the GAG chains were completely depolymerized (t1/2 = 2 to 3 hours). Neither resting nor LPS-stimulated cells sorted CSPG to intracellular storage, as is evident in many hematopoietic cells. The LPS-treated cells synthesized [35S]CSPG of smaller molecular size than did control cells, with GAG chains of approximate molecular mass of 12 kD versus 16 kD in control cells. No difference was seen in the disaccharide composition of the GAG chains; both LPS-stimulated and unstimulated cells expressed a mixture of 80% to 90% chondroitin 4-sulfate and 10% to 20% chondroitin 4,6-disulfate. N-terminal sequence and Northern blot analysis indicate that the core protein of the CSPG secreted by human macrophages is serglycin.

Blood platelets stimulate the expression of chondroitin sulfate proteoglycan in human monocytes.

Mononuclear phagocytes synthesize chondroitin sulfate proteoglycan (CSPG), which is constitutively secreted. Because mononuclear phagocytes are known to interact with blood platelets, the effect of platelets on the release of CSPG in cultured human monocytes was investigated. After 6 days in vitro, the monocytes were supplied with fresh medium with different additions and subsequently exposed to [35S]sulfate for 24 hours before the medium fractions were harvested and analyzed for content of [35S]CSPG. Indirect evidence for the release of stimulatory factors from blood platelets was found when the addition of medium containing 50% serum made from platelet-rich plasma increased the expression of [35S]CSPG almost sevenfold compared with serum-free medium, whereas medium containing 50% serum made from platelet-depleted plasma increased the expression of [35S]CSPG about fourfold. Further, direct evidence for the stimulatory effect of platelets was found as the addition of autologous platelets to serum-free medium increased the expression of [35S]CSPG about threefold, and addition of supernatant from a corresponding number of thrombin-stimulated platelets was almost as efficient. The effect of five different platelet-derived factors (which are all present in serum) was investigated. Both platelet-derived growth factor (PDGF), platelet factor 4 (PF 4), and prostaglandin E2 (PGE2) used in physiologic concentrations were found to stimulate the expression of [35S]CSPG twofold to threefold, whereas transforming growth factor-beta had a slight inhibitory effect. 12-Hydroxyeicosatetraenoic acid had no significant effect on the expression of [35S]CSPG. Further evidence for the stimulatory effect of PDGF, PF 4, and PGE2 was found as serum depleted of these factors had significantly less stimulatory effect than control serum. The increased incorporation of [35S]sulfate into [35S]CSPG in cultures stimulated with serum or platelet-derived factors was not due to differences in molecular size or extent of sulfation of the proteoglycan molecules.