Role of ventilation in airborne transmission of infectious agents in the built environment - a multidisciplinary systematic review

There have been few recent studies demonstrating a definitive association between the transmission of airborne infections and the ventilation of buildings. The severe acute respiratory syndrome (SARS) epidemic in 2003 and current concerns about the risk of an avian influenza (H5N1) pandemic, have made a review of this area timely. We searched the major literature databases between 1960 and 2005, and then screened titles and abstracts, and finally selected 40 original studies based on a set of criteria. We established a review panel comprising medical and engineering experts in the fields of microbiology, medicine, epidemiology, indoor air quality, building ventilation, etc. Most panel members had experience with research into the 2003 SARS epidemic. The panel systematically assessed 40 original studies through both individual assessment and a 2-day face-to-face consensus meeting. Ten of 40 studies reviewed were considered to be conclusive with regard to the association between building ventilation and the transmission of airborne infection. There is strong and sufficient evidence to demonstrate the association between ventilation, air movements in buildings and the transmission/spread of infectious diseases such as measles, tuberculosis, chickenpox, influenza, smallpox and SARS. There is insufficient data to specify and quantify the minimum ventilation requirements in hospitals, schools, offices, homes and isolation rooms in relation to spread of infectious diseases via the airborne route. PRACTICAL IMPLICATION: The strong and sufficient evidence of the association between ventilation, the control of airflow direction in buildings, and the transmission and spread of infectious diseases supports the use of negatively pressurized isolation rooms for patients with these diseases in hospitals, in addition to the use of other engineering control methods. However, the lack of sufficient data on the specification and quantification of the minimum ventilation requirements in hospitals, schools and offices in relation to the spread of airborne infectious diseases, suggest the existence of a knowledge gap. Our study reveals a strong need for a multidisciplinary study in investigating disease outbreaks, and the impact of indoor air environments on the spread of airborne infectious diseases.

Relation of synovitis to knee pain using contrast-enhanced MRIs

BACKGROUND

It has been suggested that synovitis causes joint pain. On non-contrast-enhanced MRIs synovial thickening cannot be assessed and on these images synovitis has been inconsistently associated with pain.

OBJECTIVE

To assess synovial thickening in relation to knee pain severity among subjects in the Multicenter Osteoarthritis Study (MOST) using contrast-enhanced (CE) MRI.

METHODS

MOST is a cohort study of people who have, or are at high risk of, knee osteoarthritis (OA). An unselected subset of 535 participants who volunteered underwent CE 1.5 T MRI of one knee. Synovitis was scored in six compartments and a summary score was created. Knee pain severity was assessed using the maximum item score on the Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain scale. The association between synovitis and pain severity was examined using a logistic regression model adjusting for age, sex, body mass index (BMI), MRI bone marrow lesions and effusions in the whole sample and in a subgroup without radiographic OA.

RESULTS

454 of the 535 subjects undergoing CE MRI had complete data on synovitis and WOMAC pain. Mean age was 59 years, mean BMI 30 and 48% were women. In knees with moderate pain, 80% had synovitis. For knee pain, synovitis conferred a 9.2-fold increased odds compared with those without synovitis. In knees without radiographic OA (n=329), there was also an association of synovitis with an increased prevalence of pain.

CONCLUSION

Synovitis has a strong relation with knee pain severity, an association detected more clearly with CE MRI than suggested by previous studies using non-CE MRI measures of synovitis.

Change in MRI-detected subchondral bone marrow lesions is associated with cartilage loss: the MOST Study. A longitudinal multicentre study of knee osteoarthritis

OBJECTIVES

To describe the natural history of subchondral bone marrow lesions (BMLs) in a sample of subjects with knee osteoarthritis (OA) or at risk of developing it. Additionally, to examine the association of change in BMLs from baseline to 30-month follow-up with the risk of cartilage loss in the same subregion at follow-up.

METHODS

1.0 T MRI was performed using proton density-weighted, fat-suppressed sequences. BML size and cartilage status were scored in the same subregions according to the WORMS system. Subregions were categorised based on comparison of baseline and follow-up BML status. A logistic regression model was used to assess the association of change in BML status with cartilage loss over 30 months using stable BMLs as the reference group.

RESULTS

395 knees were included. 66% of prevalent BMLs changed in size; 50% showed either regression or resolution at follow-up. The adjusted odds ratios (95% confidence intervals) of cartilage loss in the same subregion at follow-up for the different groups were 1.2 (0.5 to 1.6) for regressing BMLs, 0.9 (0.5 to 1.6) for resolving BMLs, 2.8 (1.5 to 5.2) for progressing BMLs, 0.2 (0.1 to 0.3) for subregions with no BMLs at baseline and follow-up and 3.5 (2.1 to 5.9) for newly developing BMLs. BML size at baseline was associated with risk of subsequent cartilage loss.

CONCLUSIONS

The majority of pre-existing BMLs decreased in size at follow-up. Absence of BMLs was associated with a decreased risk of cartilage loss, while progressing and new BMLs showed a high risk of cartilage loss in the same subregion.

Is obesity a risk factor for progressive radiographic knee osteoarthritis?

OBJECTIVE

To examine whether obesity increases the risk of progression of knee osteoarthritis (OA).

METHODS

We used data from the Multicenter Osteoarthritis Study, a longitudinal study of persons with or at high risk of knee OA. OA was characterized at baseline and 30 months using posteroanterior fixed-flexion radiographs and Kellgren/Lawrence (K/L) grading, with alignment assessed on full-extremity films. In knees with OA at baseline (K/L grade 2 or 3), progression was defined as tibiofemoral joint space narrowing on the 30-month radiograph. In knees without OA at baseline (K/L grade 0 or 1), incident OA was defined as the development of radiographic OA at 30 months. Body mass index (BMI) at baseline was classified as normal (<25 kg/m(2)), overweight (25-<30 kg/m(2)), obese (30-<35 kg/m(2)), and very obese (>or=35 kg/m(2)). The risk of progression was tested in all knees and in subgroups categorized according to alignment. Analyses were adjusted for age, sex, knee injury, and bone density.

RESULTS

Among the 2,623 subjects (5,159 knees), 60% were women, and the mean +/- SD age was 62.4 +/- 8.0 years. More than 80% of subjects were overweight or obese. At baseline, 36.4% of knees had tibiofemoral OA, and of those, only one-third were neutrally aligned. Compared with subjects with a normal BMI, those who were obese or very obese were at an increased risk of incident OA (relative risk 2.4 and 3.2, respectively [P for trend < 0.001]); this risk extended to knees from all alignment groups. Among knees with OA at baseline, there was no overall association between a high BMI and the risk of OA progression; however, an increased risk of progression was observed among knees with neutral but not varus alignment. The effect of obesity was intermediate in those with valgus alignment.

CONCLUSION

Although obesity was a risk factor for incident knee OA, we observed no overall relationship between obesity and the progression of knee OA. Obesity was not associated with OA progression in knees with varus alignment; however, it did increase the risk of progression in knees with neutral or valgus alignment. Therefore, weight loss may not be effective in preventing progression of structural damage in OA knees with varus alignment.

Protein kinase inhibitors: the tyrosine-specific protein kinases

Inhibitors for tyrosine-specific protein kinases ultimately may constitute a novel family of medicinally active agents. Unfortunately, the challenges associated with the acquisition of inhibitors for these enzyme targets are unlike any that have ever been encountered in medicinal chemistry. Protein kinases pose a variety of obstacles in regard to inhibitor design, nearly all of which deal with, in one fashion or another, the issue of specificity. The protein kinase family is extraordinarily large, with estimates that the human genome codes for as many as 2000 protein kinases. Furthermore, inhibitors that are directed to the ATP-binding sites of these enzymes must contend with the presence of a large number of other ATP-utilizing proteins and, in addition, must compete with the high intracellular concentrations of ATP. Although specificity ultimately may prove to be less of a concern with peptide-based inhibitors, these agents neither are readily bioavailable nor do they bind with the requisite affinity to the protein-binding domains of protein kinases. In the face of these challenges, an enormous number of inhibitors have been synthesized and evaluated for the tyrosine-specific protein kinases. The advantages and disadvantages associated with inhibitors that are targeted to the ATP-binding site, the protein-binding site, and nonactive site regions required for appropriate subcellular localization are discussed. The handful of tyrosine-specific protein kinases that have been selected as targets to date and their roles in various disease processes are described as well.

Synovitis and the risk of knee osteoarthritis: the MOST Study

OBJECTIVE

To identify the independent relation of synovitis with incident radiographic knee osteoarthritis (OA) after adjusting for other structural factors known to cause synovitis.

DESIGN

We examined MRIs from knees that developed incident radiographic OA from the Multicenter Osteoarthritis Study (MOST) and compared these case knees with controls that did not develop OA. We examined baseline MRIs for knees developing OA at any time up to 84 months follow-up. We scored lesions in cartilage, meniscus, bone marrow and synovitis. Synovitis scores were summed (0-9) across three regions, suprapatellar, infrapatellar and intercondylar region, each of which was scored 0-3. After bivariate analyses examining each factor's association with incidence, we carried out multivariable regression analyses adjusting for age, sex, BMI, alignment and cartilage and meniscal damage.

RESULTS

We studied 239 case and 731 control knees. In bivariate analyses, cartilage lesions, meniscal damage, synovitis and bone marrow lesions were all risk factors for OA. After multivariable analyses, synovitis was associated with incident OA. A higher synovitis score increased the risk of incident OA (adjusted OR per unit increase 1.1; (95% CI 1.0, 1.2, P = .02)), but increased risk was associated only with synovitis scores of ≥3 (adjusted OR 1.6; 95% CI 1.2, 2.1, P = .003).

CONCLUSIONS

Synovitis, especially when there is a substantial volume within the knee, is an independent cause of OA.

First-in-human phase 1 study of the anti-TIGIT antibody vibostolimab as monotherapy or with pembrolizumab for advanced solid tumors, including non-small cell lung cancer

BACKGROUND

In this first-in-human phase 1 study, we investigated the safety and efficacy of the anti-TIGIT antibody vibostolimab as monotherapy or in combination with pembrolizumab.

METHODS

Part A enrolled patients with advanced solid tumors and part B enrolled patients with non-small cell lung cancer (NSCLC). Patients received vibostolimab 2.1-700 mg alone or with pembrolizumab 200 mg in part A and vibostolimab 200 mg alone or with pembrolizumab 200 mg in part B. Primary end points were safety and tolerability. Secondary end points included pharmacokinetics and objective response rate (ORR) per RECIST v1.1.

RESULTS

Part A enrolled 76 patients (monotherapy, 34; combination therapy, 42). No dose-limiting toxicities were reported. Across doses, 56% of patients receiving monotherapy and 62% receiving combination therapy had treatment-related adverse events (TRAEs); grade 3-4 TRAEs occurred in 9% and 17% of patients, respectively. The most common TRAEs were fatigue (15%) and pruritus (15%) with monotherapy and pruritus (17%) and rash (14%) with combination therapy. Confirmed ORR was 0% with monotherapy and 7% with combination therapy. In part B, 39 patients had anti-PD-1/PD-L1-naïve NSCLC (all received combination therapy) and 67 had anti-PD-1/PD-L1-refractory NSCLC (monotherapy, 34; combination therapy, 33). In patients with anti-PD-1/PD-L1-naive NSCLC: 85% had TRAEs-the most common were pruritus (38%) and hypoalbuminemia (31%); confirmed ORR was 26%, with responses occurring in both PD-L1-positive and PD-L1-negative tumors. In patients with anti-PD-1/PD-L1‒refractory NSCLC: 56% receiving monotherapy and 70% receiving combination therapy had TRAEs-the most common were rash and fatigue (21% each) with monotherapy and pruritus (36%) and fatigue (24%) with combination therapy; confirmed ORR was 3% with monotherapy and 3% with combination therapy.

CONCLUSION

Vibostolimab plus pembrolizumab was well tolerated and demonstrated antitumor activity in patients with advanced solid tumors, including patients with advanced NSCLC.

Bone marrow lesions and joint effusion are strongly and independently associated with weight-bearing pain in knee osteoarthritis: data from the osteoarthritis initiative

OBJECTIVE

It is widely believed that there are multiple sources of pain at a tissue level in osteoarthritis (OA). Magnetic Resonance Images (MRIs) provide a wealth of anatomic information and may allow identification of specific features associated with pain. We hypothesized that in knees with OA, bone marrow lesions (BMLs), synovitis, and effusion would be associated with weight-bearing and (less so with) non-weight-bearing pain independently.

METHODS

In a cross-sectional study of persons with symptomatic knee OA using univariate and multivariate logistic regressions with maximal BML, effusion, and synovitis defined by Boston Leeds Osteoarthritis Knee Score as predictors, and knee pain using weight-bearing and non-weight-bearing Western Ontario and McMaster University OA Index pain questions as the outcome, we tested the association between MRI findings and knee symptoms.

RESULTS

160 participants, mean age 61 (+/-9.9), mean body mass index (BMI) 30.3 (+/-4.7) and 50% female, stronger associations were seen with weight-bearing compared with non-weight-bearing knee pain with adjusted risk ratios (RRs) of weight-bearing knee pain, for increasing maximal BML scores of 1.0 (referent) (maximal BML=0), 1.2, 1.9, and 2.0 (P for trend=0.006). For effusion scores, adjusted RRs of knee pain were 1.0, 1.7, 2.0, and 2.6 (P for trend=0.0004); and for synovitis scores, adjusted ORs were 1.0, 1.4, 1.5, and 1.9 (P for trend=0.22).

CONCLUSION

Cross-sectionally, maximal BML and effusion scores are independently associated with weight-bearing and less so with non-weight-bearing knee pain, supporting the idea that pain in OA is multifactorial. These MRI features should be considered as possible new treatment targets in knee OA.

Osteophytes and progression of knee osteoarthritis

OBJECTIVES

Osteophytes are thought to stabilize an osteoarthritic joint, thereby preventing structural progression. Meagre longitudinal data suggest, however, that they are associated with an increased risk of structural progression. Our objective was to evaluate the effect of osteophyte size on radiographic progression in osteoarthritis (OA).

METHODS

Using data from a natural history study of persons with symptomatic knee OA, we obtained fluoroscopically positioned postero-anterior (PA) radiographs at baseline, 15 and 30 months. Using an atlas, osteophyte size was scored on a scale of 0-3 at each of four sites on the PA film and, for each knee, both compartment-specific (i.e. medial; lateral) and overall osteophyte scores were computed. Progression was defined as an increase over follow-up in medial or lateral joint space narrowing, based on a semiquantitative grading. Mechanical alignment was assessed using long limb films at the 15 month examination. Logistic regression was used to evaluate the relation of osteophyte size with progression, adjusting for age, gender and body mass index, and with and without adjustment for alignment.

RESULTS

Of 270 subjects who had 470 eligible knees with follow-up, 104 (22%) knees showed progression. Overall, osteophyte score modestly increased the risk of progression [odds ratio (OR) per S.D. increase of osteophyte score=1.4 (95% CI 1.1, 1.8, P=0.02)], but this effect weakened and became non-significant after adjustment for limb alignment (OR=1.3). Compartment osteophyte score was strongly associated with malalignment to the side of the osteophyte (e.g. medial osteophyte and varus). Compartment-specific osteophyte score markedly increased the risk of ipsilateral progression (e.g. medial osteophytes --> medial progression) [OR per S.D.=1.9 (95% CI 1.5, 2.5, P<0.001)] and decreased the risk of contralateral progression [OR per S.D.= 0.6 (95% CI 0.5, 0.8, P=0.002)], but these associations diminished when we adjusted for limb alignment (OR=1.5 and 0.7 respectively).

CONCLUSIONS

Large osteophytes do not affect the risk of structural progression. They are strongly associated with malalignment to the side of the osteophyte, and any relation they have with progression is partly explained by the association of malalignment with progression.

Cigarette smoking and the risk for cartilage loss and knee pain in men with knee osteoarthritis

OBJECTIVE

To examine the effects of smoking on cartilage loss and pain at the knee in individuals with knee osteoarthritis.

METHODS

159 men with symptomatic knee osteoarthritis who participated in a 30-month, prospective, natural history study of knee osteoarthritis were examined. The more symptomatic knee was imaged using magnetic resonance imaging (MRI) at baseline, and again at 15 and 30 months of follow-up. Cartilage was scored using the Whole-Organ MRI Score semiquantitative method at the medial and lateral tibiofemoral joints and at the patellofemoral joint. At baseline and follow-up visits, the severity of knee pain was assessed using a Visual Analogue Scale pain score (0-100 mm).

RESULTS

Among the 159 men, 19 (12%) were current smokers at baseline. Current smokers were younger (mean (standard deviation (SD)) age 62 (9) v 69 (9) years) and leaner (mean (SD) body mass index (BMI): 28.9 (3.2) v 31.3 (4.8) kg/m(2)) than men who were not current smokers. When adjusted for age, BMI and baseline cartilage scores, men who were current smokers were found to have an increased risk for cartilage loss at the medial tibiofemoral joint (odds ratio (OR) 2.3, 95% confidence interval (CI) 1.0 to 5.4) and the patellofemoral joint (OR 2.5, 95% CI 1.1 to 5.7). Current smokers also had higher adjusted pain scores at baseline (60.5 v 45.0, p<0.05) and at follow-up (59.4 v 44.3, p<0.05) than men who were not current smokers.

CONCLUSIONS

Men with knee osteoarthritis who smoke sustain greater cartilage loss and have more severe knee pain than men who do not smoke.

The association between patellar alignment and patellofemoral joint osteoarthritis features--an MRI study

OBJECTIVE

The aim of our study was to evaluate the association between patellar alignment (using standard MRI images of extended knees) and MRI indices of patellofemoral (PF) osteoarthritis (OA) features.

METHODS

In this cross-sectional observational study, subjects were recruited to participate in the Boston Osteoarthritis of the Knee Study (BOKS). The association of patellar alignment [patellar length ratio (PLR), sulcus angle (SA), lateral patellar tilt angle (LPTA) and bisect offset (BO)] with measures of PF OA [cartilage morphology and bone marrow lesion (BML) in the medial and lateral PF compartment] were examined using a logistic regression model while adjusting for age, sex and BMI.

RESULTS

Study sample comprised 126 males (mean age 68.0, BMI 31.2) and 87 females (mean age 64.7, BMI 31.6). All measurements of patellar alignment were statistically significantly associated with cartilage morphology and BML in the lateral compartment of PF joint. PLR and SA were significantly associated with medial cartilage loss. With increasing PLR there was an increased prevalence of lateral and medial cartilage loss as well as of lateral BML. Increasing SA was positively associated with increased lateral and medial cartilage loss and lateral BML. LPTA range was negatively associated with lateral cartilage loss and BML. More laterally displaced patella (higher BO) was associated with increased lateral cartilage loss and BML.

CONCLUSIONS

The results of our study clearly indicated that patellar alignment is associated with manifestations of PF OA such as cartilage thickness loss and BML.

High systemic bone mineral density increases the risk of incident knee OA and joint space narrowing, but not radiographic progression of existing knee OA: the MOST study

OBJECTIVES

Previous studies suggest that high systemic bone mineral density (BMD) is associated with incident knee osteoarthritis (OA) defined by osteophytes but not with joint space narrowing (JSN), and are inconsistent regarding BMD and progression of existing OA. The association of BMD with incident and progressive tibiofemoral OA was tested in a large prospective study of men and women aged 50-79 years with or at risk for knee OA.

METHODS

Baseline and 30-month weight-bearing posteroanterior and lateral knee radiographs were scored for Kellgren-Lawrence (K-L) grade, JSN and osteophytes. Incident OA was defined as the development of K-L grade > or =2 at follow-up. All knees were classified for increases in grade of JSN and osteophytes from baseline. The association of gender-specific quartiles of baseline BMD with risk of incident and progressive OA was analysed using logistic regression, adjusting for covariates.

RESULTS

The mean (SD) age of 1754 subjects was 63.2 (7.8) years and body mass index was 29.9 (5.4) kg/m(2). In knees without baseline OA, higher femoral neck and whole body BMD were associated with an increased risk of incident OA and increases in grade of JSN and osteophytes (p<0.01 for trends); adjusted odds were 2.3-2.9-fold greater in the highest compared with the lowest BMD quartiles. In knees with existing OA, progression was not significantly related to BMD.

CONCLUSIONS

In knees without OA, higher systemic BMD was associated with a greater risk of the onset of JSN and K-L grade > or =2. The role of systemic BMD in early knee OA pathogenesis warrants further investigation.

Change in cartilage morphometry: a sample of the progression cohort of the Osteoarthritis Initiative

OBJECTIVE

The performance characteristics of hyaline articular cartilage measurement on magnetic resonance imaging (MRI) need to be accurately delineated before widespread application of this technology. Our objective was to assess the rate of natural disease progression of cartilage morphometry measures from baseline to 1 year in knees with osteoarthritis (OA) from a subset of participants from the Osteoarthritis Initiative (OAI).

METHODS

Subjects included for this exploratory analysis are a subset of the approximately 4700 participants in the OAI Study. Bilateral radiographs and 3T MRI (Siemans Trio) of the knees and clinical data were obtained at baseline and annually in all participants. 160 subjects from the OAI Progression subcohort all of whom had both frequent symptoms and, in the same knee, radiographic OA based on a screening reading done at the OAI clinics were eligible for this exploratory analysis. One knee from each subject was selected for analysis. 150 participants were included. Using sagittal 3D DESSwe (double echo, steady-state sequence with water excitation) MR images from the baseline and 12 follow-up month visit, a segmentation algorithm was applied to the cartilage plates of the index knee to compute the cartilage volume, normalised cartilage volume (volume normalised to bone surface interface area), and percentage denuded area (total cartilage bone interface area denuded of cartilage).

RESULTS

Summary statistics of the changes (absolute and percentage) from baseline at 1 year and the standardised response mean (SRM), ie, mean change divided by the SD change were calculated. On average the subjects were 60.9 years of age and obese, with a mean body mass index of 30.3 kg/m2. The SRMs for cartilage volume of various locations are: central medial tibia -0.096; central medial femur -0.394; and patella -0.198. The SRMs for normalised cartilage volume of the various locations are central medial tibia -0.044, central medial femur -0.338 and patella -0.193. The majority of participants had a denuded area at baseline in the central medial femur (62%) and central medial tibia (60%). In general, the SRMs were small.

CONCLUSIONS

These descriptive results of cartilage morphometry and its change at the 1-year time point from the first substantive MRI data release from the OAI Progression subcohort indicate that the annualised rates of change are small with the central medial femur showing the greatest consistent change.

Integrin alphanvbeta6 acts as a prognostic indicator in gastric carcinoma

AIMS

To investigate the relationships between integrin alphanubeta6 expression and the clinical-pathological features of gastric carcinoma and whether integrin alphanubeta6 can act as a prognostic indicator in gastric carcinoma.

MATERIALS AND METHODS

We generated the microarray of 300 human gastric carcinoma specimens, and used the method of immunohistochemistry to investigate the expression of alphanubeta6 in them and the relationships between the expression of alphanubeta6 and the clinical-pathological features of the tumours. Meanwhile, we retrospectively analysed the relationship between alphanubeta6 expression and the survival times of the patients.

RESULTS

The expression of alphanubeta6 was detected in 36.7% of gastric carcinomas, and the expression was associated with Lauren type, differentiation, N stage and TNM stage of the tumours (the P values were 0.004, 0.035, 0.024 and 0.001, respectively). The Kaplan-Meier plot showed that patients who were alphanubeta6 negative had much longer survival times than those who were alphanubeta6 positive (P<0.0001). The survival estimates showed a striking difference in median survival between the negative and positive alphanubeta6 expression patients, especially in early stage tumours. Univariate analysis indicated that significant factors for prognosis included alphanubeta6 expression, differentiation, TNM stage, T stage, N stage, M stage and R classification (R0: potentially curative resection; R1: had residual microscopic disease after resection; R2: had residual macroscopic disease after resection), whereas in multivariate analysis using the Cox regression model, only alphanubeta6 expression, M stage, TNM stage and R classification retained significance for prognosis.

CONCLUSIONS

Positive alphanubeta6 expression in gastric carcinoma is linked to significantly reduced survival times and, even more important, is that its value as a prognostic marker is significant for early stage tumours.

Trapeziometacarpal subluxation predisposes to incident trapeziometacarpal osteoarthritis (OA): the Framingham Study

OBJECTIVE

Osteoarthritis (OA) of the thumb carpo-metacarpal joint is a common condition that can lead to substantial pain, instability, deformity, and loss of motion. It has been hypothesized that instability of the trapeziometacarpal joint combined with strenuous use can potentially lead to OA. However, as yet there have been no longitudinal evaluations to determine if this hypothesis is true. We examined the relation of radial subluxation to the risk of radiographic OA at trapeziometacarpal joint.

METHODS

We conducted a nested case-control study. We restricted our evaluation of cases to subjects with no radiographic trapeziometacarpal OA at baseline (1967). We defined incident trapeziometacarpal OA as the development of a modified Kellgren and Lawrence grade>or=2 in that joint at a later examination (1992-1993). Radial subluxation of the base of the first metacarpal off the trapezium and the amount of the base of the first metacarpal covering the articulating surface of the trapezium were measured using a digital calculation caliper. We examined the relation of gender-specific quartile groups of radial subluxation to the risk of trapeziometacarpal OA using a conditional logistic regression model.

RESULTS

We assessed 203 men and 431 women. After adjusting for age, handedness, number of other joints with OA, and grip strength, the odds ratios for the risk of trapeziometacarpal OA in men were 1.0, 1.8, 2.7, and 3.1 from the lowest quartile of radial subluxation to the highest quartile, respectively (P for trend=0.015). There was no significant relationship between radial subluxation quartiles and incident trapeziometacarpal OA in women.

CONCLUSION

This study provides evidence that radial subluxation predisposes to subsequent OA of the trapeziometacarpal joint in men.

Efficacy and safety of continuous 4-year telbivudine treatment in patients with chronic hepatitis B

In the phase-III GLOBE/015 studies, telbivudine demonstrated superior efficacy vs lamivudine during 2-year treatment in HBeAg-positive and HBeAg-negative chronic hepatitis B (CHB). After completion, 847 patients had an option to continue telbivudine treatment for further 2 years. A total of 596 (70%) of telbivudine-treated patients, who were serum HBV DNA positive or negative and without genotypic resistance to telbivudine at the end of the GLOBE/015 trials, were enrolled into a further 2-year extension study. A group of 502 patients completed 4 years of continuous telbivudine treatment and were included in the telbivudine per-protocol population. Amongst 293 HBeAg-positive patients, 76.2% had undetectable serum HBV DNA and 86.0% had normal serum ALT at the end of 4 years. Notably, the cumulative rate of HBeAg seroconversion was 53.2%. Amongst 209 HBeAg-negative patients, 86.4% had undetectable HBV DNA and 89.6% had normal serum ALT. In patients who had discontinued telbivudine treatment due to HBeAg seroconversion, the HBeAg response was durable in 82% of patients (median 111 weeks of off-treatment follow-up). The cumulative 4-year resistance rate was 10.6% for HBeAg-positive and 10.0% for HBeAg-negative patients. Most adverse events were mild or moderate in severity and transient. Renal function measured by estimated glomerular filtration rate (eGFR) increased by 14.9 mL/min/1.73 m(2) (16.6%) from baseline to 4 years (P < 0.0001). In conclusion, in HBeAg-positive and HBeAg-negative CHB patients without resistance after 2 years, two additional years of telbivudine treatment continued to provide effective viral suppression with a favourable safety profile. Moreover, telbivudine achieved 53% of HBeAg seroconversion in HBeAg-positive patients.

Cyclic AMP-independent activation of protein kinase A by vasoactive peptides

Protein kinase A (PKA) is an important effector enzyme commonly activated by cAMP. The present study focuses on our finding that the vasoactive peptide endothelin-1 (ET1), whose signaling is not coupled to cAMP production, stimulates PKA in two independent cellular models. Using an in vivo assay for PKA activity, we found that ET1 stimulated PKA in HeLa cells overexpressing ET1 receptors and in aortic smooth muscle cells expressing endogenous levels of ET1 receptors. In these cell models, ET1 did not stimulate cAMP production, indicating a novel mechanism for PKA activation. The ET1-induced activation of PKA was found to be dependent on the degradation of inhibitor of kappaB, which was previously reported to bind and inhibit PKA. ET1 potently stimulated the nuclear factor-kappaB pathway, and this effect was inhibited by overexpression of the inhibitor of kappaB dominant negative mutant (IkappaBalpham) and by treatment with the proteasome inhibitor MG-132. Importantly, IkappaBalpham and MG-132 had similar inhibitory effects on ET1-induced activation of PKA without affecting G(s)-mediated activation of PKA or ET1-induced phosphorylation of mitogen-activated protein kinase. Finally, another vasoactive peptide, angiotensin II, also stimulated PKA in a cAMP-independent manner in aortic smooth muscle cells. These findings suggest that cAMP-independent activation of PKA might be a general response to vasoactive peptides.

Interaction of heterotrimeric G13 protein with an A-kinase-anchoring protein 110 (AKAP110) mediates cAMP-independent PKA activation

Heterotrimeric G proteins and protein kinase A (PKA) are two important transmitters that transfer signals from a wide variety of cell surface receptors to generate physiological responses. The established mechanism of PKA activation involves the activation of the Gs-cAMP pathway. Binding of cAMP to the regulatory subunit of PKA (rPKA) leads to a release and subsequent activation of a catalytic subunit of PKA (cPKA). Here, we report a novel mechanism of PKA stimulation that does not require cAMP. Using yeast two-hybrid screening, we found that the alpha subunit of G13 protein interacted with a member of the PKA-anchoring protein family, AKAP110. Using in vitro binding and coimmunoprecipitation assays, we have shown that only activated G alpha 13 binds to AKAP110, suggesting a potential role for AKAP110 as a G alpha subunit effector protein. Importantly, G alpha 13, AKAP110, rPKA, and cPKA can form a complex, as shown by coimmunoprecipitation. By characterizing the functional significance of the G alpha 13-AKAP110 interaction, we have found that G alpha 13 induced release of the cPKA from the AKAP110-rPKA complex, resulting in a cAMP-independent PKA activation. Finally, AKAP110 significantly potentiated G alpha 13-induced activation of PKA. Thus, AKAP110 provides a link between heterotrimeric G proteins and cAMP-independent activation of PKA.

Integrin-mediated signalling of gelatinase B secretion in colon cancer cells

The progression of colon cancer has been linked to both cell adhesion molecules called integrins and matrix-degrading enzymes called metalloproteinases. Herein we report that the alpha v beta 6 integrin expressed in colon cancer cells induces gelatinase B secretion through the C-terminal cytoplasmic extension unique to the beta 6 integrin subunit, and that this ligand-independent event involves activation of the protein-kinase-C pathway.

Cartilage loss occurs in the same subregions as subchondral bone attrition: a within-knee subregion-matched approach from the Multicenter Osteoarthritis Study

OBJECTIVE

By magnetic resonance imaging (MRI), subchondral bone attrition (SBA) can be seen in early osteoarthritis (OA), but the significance of this is unknown. We therefore evaluated whether SBA was associated with cartilage loss within the same subregion of the knee.

METHODS

The Multicenter Osteoarthritis Study is a cohort of individuals who have or are at high risk for knee OA. At baseline and 30 months, participants' knee MRIs were graded using the Whole-Organ Magnetic Resonance Imaging Score in the 10 subregions of the tibiofemoral joint for cartilage morphology and SBA. We conducted analyses within a knee to eliminate between-person confounding, using an M:N (cases:controls) matched case-control approach with the 10 subregions of a person's knee forming a matched set. Cases within a knee were defined as subregions with cartilage loss, while controls were subregions in that same knee without cartilage loss. We evaluated the association of cartilage loss over 30 months with the presence of baseline SBA in the same subregion within that knee using conditional logistic regression.

RESULTS

SBA was associated with an odds ratio of 7.5 (95% confidence interval 5.6-9.9, P < 0.0001) for cartilage loss in the same subregion compared with subregions without any baseline SBA in our sample of 459 knees from participants, 64% of whom were women, with a mean age of 63 years and a mean body mass index of 30.5 kg/m(2).

CONCLUSION

SBA is strongly associated with cartilage loss within the same subregion of a knee. SBA may directly influence overlying cartilage loss or serve as a marker of an area undergoing great compressive stress and in which cartilage loss is inevitable.

Knee osteoarthritis and all-cause mortality: the Wuchuan Osteoarthritis Study

BACKGROUND

Previous studies showed that knee osteoarthritis (OA) is associated with increased mortality in Caucasians. While prevalence of knee OA is higher in Chinese than in Caucasians, no study has examined whether knee OA increases mortality in Chinese population.

METHODS

Between 8/2005-10/2005 1025 residents aged ≥50 years were recruited in randomly selected rural communities in Wuchuan, China. Subjects completed a home interview and had weight-bearing posteroanterior semiflexed view of radiographs at tibiofemoral joints and skyline view of radiographs at patellofemoral joints, and were followed until end of 2013. A knee was defined as having radiographic osteoarthritis (ROA) if either Kellgren/Lawrence (KL) score at tibiofemoral joint ≥2 or presence of OA at patellofemoral joint based on OARSI criteria. Symptomatic knee osteoarthritis (SxOA) was defined if both pain (i.e., knee pain occurred on most days in past month) and ROA were present at the same knee. We examined the relation of knee SxOA and knee ROA to the all-cause mortality, respectively, using Cox-proportional hazard models adjusting for potential confounders.

RESULTS

Over the follow-up period 99 subjects died. The mortality rates were 32.6 (95% confidence interval (CI): 19.6-54.0) and 10.9 (95% CI: 8.8-13.5) per 1000 person-years among subjects with and without SxOA, respectively. Multivariable adjusted hazard ratio of all-cause mortality for knee SxOA was 1.9 (95% CI: 1.0-3.5). However, no such association was observed for knee ROA (hazard ratio = 1.2, 95% CI: 0.7-1.9).

CONCLUSIONS

Knee SxOA was associated with an increased risk of all-cause mortality among the residents in the rural areas of China.