Collagen fibrillogenesis in situ: fibril segments become long fibrils as the developing tendon matures

Tissue architecture, stability, and mechanical attributes are all determined by the structure and organization of collagen fibrils. Therefore, the characterization of fibril growth steps and determination of how this growth is regulated is essential to the elucidation of how tissues are assembled. We have proposed that fibril segments are intermediates in the formation of mature fibrils. The purpose of this study was to determine the length and structure of fibrils within a relatively mature tendon. The in situ determination of length performed here was only the second direct determination of fibril length in a vertebrate connective tissue and the first for a relatively mature tissue. The data demonstrate that the fibrils were discontinuous at 18 days of tendon development. However, both ends were not present in any of the analyzed fibrils within the 18-day tendon. Because the data set was 50-60 microm, this indicates a mean fibril length greater than 60 microm. These data are in contrast to data from the 14-day tendon, in which 80% of the fibrils had both ends in a 26-microm data set and the mean segment length was shown to be 10-30 microm. There were equal numbers of alpha and beta ends in the 18-day tendon. The structure of the ends was comparable to that in the less mature tendon. The data also indicate that fibril asymmetry and structure were maintained. The increase in fibril length is interpreted as being the result of a post-depositional, regulated assembly of segments via a lateral association/fusion to form mature fibrils. This hypothesis predicts an increase in diameter at this stage of development. The diameter increases have been documented, but this is the first demonstration of increases in length and maintenance of segment structure during this important stage of tendon development.

A post hoc analysis of dalteparin versus oral anticoagulant (VKA) therapy for the prevention of recurrent venous thromboembolism (rVTE) in patients with cancer and renal impairment

Venous thromboembolism (VTE) is a common and serious complication in patients with cancer; treatment guidelines recommend extended therapy of ≥6 months with low-molecular-weight heparin (LMWH) for treatment and prevention of recurrent VTE (rVTE) in this population. This post hoc analysis used data from the CLOT study—a phase III, randomized, open-label, controlled study (N = 676)—to compare the efficacy and safety of dalteparin, a LMWH, versus vitamin K antagonist (VKA) for prevention of rVTE in patients with cancer and renal impairment (creatinine clearance <60 ml/min). Overall, 162/676 (24 %) patients had renal impairment at baseline. Patients received subcutaneous dalteparin 200 IU/kg once daily during month 1, followed by 150 IU/kg once daily for months 2–6; or VKA once daily for 6 months, with initial overlapping subcutaneous dalteparin 200 IU/kg once daily for ≥5 days until international normalized ratio was 2.0–3.0 for 2 consecutive days. Endpoints included the rates of rVTE (primary) and bleeding events. Overall, fewer dalteparin-treated patients (2/74 [2.7 %]) experienced ≥1 adjudicated symptomatic rVTE compared with VKA-treated patients (15/88 [17.0 %]; hazard ratio = 0.15 [95 % confidence interval 0.03–0.65]; p = 0.01). Bleeding event rates for both treatments were similar (p = 0.47). In summary, compared with VKA, dalteparin significantly reduced risk of rVTE in patients with cancer and renal impairment (p = 0.01) while exhibiting a comparable safety profile. This analysis supports dosing patients with renal impairment in accordance with patients with normal renal function; however, anti-Xa monitoring could be considered to further support safety in selected patients, particularly those with very severe renal impairment.

Combined phacoemulsification and transpupillary drainage of silicone oil: results and complications

AIM

To review retrospectively 74 consecutive cases of combined phacoemulsification and transpupillary drainage of silicone oil.

METHODS

Candidate patients for intraocular silicone oil removal and cataract extraction underwent combined phacoemulsification and transpupillary drainage of silicone oil through a planned posterior capsulorrhexis and without the use of a pars plana infusion line.

RESULTS

The retina remained attached in 59 (79.7%) patients postoperatively. In this success group, the postoperative visual acuity improved in 42 (71.2%) patients. There was no association between age, duration of silicone oil tamponade, preoperative diagnosis, macular status or number and nature of previous surgery, and the incidence of redetachment following silicone oil removal.

CONCLUSION

Combined phacoemulsification and transpupillary drainage of silicone oil is a safe and reliable technique that offers the main advantage of diminished surgical trauma.

Patients with Epilepsy: A High-Risk Population Prone to Severe Burns as a Consequence of Seizures While Showering

We document the severe burns sustained by three patients with epilepsy who suffered seizures while showering. On the basis of the circumstances of these accidents, we suggest preventative measures to help other patients with epilepsy avoid similar burn injuries. Patient data collected from January 1987 to May 2004 by the Burn Unit of the Department of Plastic Surgery, University of Aachen, Germany, were reviewed. Three patients with epileptic disorders were found who suffered severe burn injuries caused by seizures that occurred while showering. Scald location and depth was assessed. Three patients (two women, one man) sustained extensive scald injuries after epileptic seizures while showering. Burn extent ranged from 20% to 35% TBSA. Scalds primarily affected the trunk, legs, arms, and buttocks. Two of the three patients used showers with levers for controlling water temperature. Safety devices for limiting water temperature were absent. All patients used shower cubicles. Patients with epilepsy may sustain serious burns, typically affecting the trunk, legs, arms, and buttocks, when a seizure occurs while showering. We suggest that individuals with epilepsy use showers designed with pirouetting taps, rather than levers, to regulate water temperature. Pirouetting taps are less likely to be shifted out of position during a seizure. We also recommend that epileptic patients have safety devices installed in their water heaters that limit maximum water temperature. Such safety devices prevent scald injury. And, finally, we suggest that people with comparable disorders generally avoid using shower cubicles. Instead, showers with curtains should be used, which may allow occupants to escape from dangerously hot shower water more easily.

Impaired inhibition of NF-kappaB activity by melanoma-associated p16INK4a mutations

The cyclin-dependent kinase inhibitor p16INK4a has been identified as tumor suppressor and melanoma predisposition gene. While its cell cycle inhibitory ability is important in protecting cells from uncontrolled growth and possible tumor formation, other functions of p16INK4a are likely to contribute to its nature as a tumor suppressor. p16INK4a binding and inhibition of the transcription factor NF-kappaB has been shown and is consistent with the reports of abnormally increased NF-kappaB activity in various cancers including melanoma. Here, we present evidence that wild type p16INK4a binds to the NF-kappaB subunit RelA more efficiently than melanoma-associated p16INK4a mutations. Furthermore, whereas wild type p16INK4a strongly inhibits NF-kappaB transcriptional activity, a subset of melanoma-associated p16INK4a mutants show reduced NF-kappaB inhibitory function. p16INK4a does not affect NF-kappaB nuclear translocation or DNA binding, suggesting a mechanism that reduces NF-kappaB transactivation activity.

Low-molecular-weight-heparin versus a coumarin for the prevention of recurrent venous thromboembolism in high- and low-risk patients with active cancer: a post hoc analysis of the CLOT Study

In patients with active cancer and acute venous thromboembolism (VTE), the low-molecular-weight-heparin (LMWH) dalteparin is more effective than vitamin K antagonist (VKA) in reducing the risk of recurrent venous thromboembolism (rVTE) without increasing the risk of bleeding. However, the relative benefit of LMWH versus VKA in patients with active cancer at high or low risk of rVTE and bleeding is unclear. This post hoc analysis used data from the CLOT study to explore the efficacy and safety of LMWH versus VKA in preventing recurrent thrombosis in high- and low-risk patients with active cancer. High-risk patients were defined by metastatic disease and/or antineoplastic treatment at baseline; low-risk patients presented with neither. Among high-risk patients, rVTE occurred in 25/318 (8%) (LMWH) versus 53/314 (17%) (VKA) (hazard ratio, 0.44; p = 0.001). No significant difference was detected in the rate of major or any bleeding. The 6-month mortality rate was 40% (LMWH) versus 41% (VKA). In low-risk patients, 2/20 (10%) (LMWH) had rVTE versus 0/24 (0%) (VKA) (hazard ratio, not estimable; p = 0.998). No significant difference was detected in the rate of major or any bleeding. The 6-month mortality rate was 20% (LMWH) versus 29% (VKA). In patients with cancer-associated thrombosis at high risk of rVTE and bleeding, the LMWH dalteparin was more effective than VKA in reducing the risk of rVTE without increasing the risk of bleeding. No difference in rate of rVTE or bleeding was observed between LMWH and VKA among low-risk patients.

Obesity is associated with a slower response to initial phenprocoumon therapy whereas CYP2C9 genotypes are not

BACKGROUND

Initiation of phenprocoumon therapy is associated with a variable individual response. The CYP2C9 genotype has been shown to influence the response to warfarin therapy, but such an effect on phenprocoumon therapy remains uncertain.

METHOD

Two hundred sixty hospital patients started on phenprocoumon were recruited for this study. Body mass index (BMI), waist and hip circumference, dietary habits, comorbidity, and comedication were initially assessed. A 5' exonuclease assay (TaqManR) was used to analyze the presence of five polymorphisms of the CYP2C9 gene in each of the study patients. Study endpoints included the time necessary to achieve the international normalized ratio (INR) target (INR >2) and the total drug amount required to attain target INR. For 250 of 260 patients, the subsequent required daily maintenance dose of phenprocoumon was also recorded.

RESULTS

Both the necessary time and total dose required to attain target INR correlated significantly with BMI. The leaner the patient, the shorter the required time interval [BMI <22 (n=31), 5.48+/-2.49 days; BMI 22-25 (n=70), 6.09+/-2.40; BMI 25-30 (n=113), 6.76+/-3.61; BMI >30 (n=46), 8.50+/-5.75; p=0.001] and the lower the required dosage until the therapeutic range was achieved [BMI <22 (n=31), 23.8+/-12.1 mg; BMI 22-25 (n=70), 25.9+/-11.4 mg; BMI 25-30 (n=113), 29.6+/-25.2; BMI >30 (n=46), 35.8+/-19.7; p=0.027]. Overweight and waist circumference as a surrogate marker for abdominal fat were also associated significantly with these two parameters. Moreover, obesity was associated with a lower body-weight-adjusted maintenance dosage. All CYP2C9 genotypes that were tested failed to reveal an association with individual response variability.

CONCLUSION

Patient obesity appears to directly correspond to the amount of phenprocoumon required during initiation of therapy. The CYP2C9 genotype was not shown to influence the necessary therapeutic dosage.

Suppression of MHD fluctuations leading to improved confinement in a gun-driven spheromak

Magnetic fluctuations have been reduced to approximately 1% during discharges on the Sustained Spheromak Physics Experiment by shaping the spatial distribution of the bias magnetic flux in the device. In the resulting quiescent regime, the safety factor profile is nearly flat in the plasma and the dominant ideal and resistive MHD modes are greatly reduced. During this period, the temperature profile is peaked at the magnetic axis and maps onto magnetic flux contours. Energy confinement time is improved over previous reports in a driven spheromak.

New mode of operating a magnetized coaxial plasma gun for injecting magnetic helicity into a spheromak

By operating a magnetized coaxial plasma gun continuously with just sufficient current to enable plasma ejection, large gun-voltage spikes (approximately 1 kV) are produced, giving the highest sustained voltage approximately 500 V and highest sustained helicity injection rate observed in the Sustained Spheromak Physics Experiment. The spheromak magnetic field increases monotonically with time, exhibiting the lowest fluctuation levels observed during formation of any spheromak (B/B>/=2%). The results suggest an important mechanism for field generation by helicity injection, namely, the merging of helicity-carrying filaments.

Dalteparin or vitamin K antagonists to prevent recurrent venous thromboembolism in cancer patients: a patient-level economic analysis for France and Austria

BACKGROUND

International guidelines recommend extended duration secondary prophylaxis in cancer patients who develop primary venous thromboembolism (VTE). Agent selection is guided in part by one large randomized trial (i.e., CLOT; Lee et al., N Engl J Med 349:146-53, 2003) which demonstrated that dalteparin reduced the relative risk of recurrence by 52% compared with oral vitamin K antagonists (VKA; HR = 0.48, 95% CI, 0.30 to 0.77). In a subgroup analysis from that same trial, patients with renal impairment also derived benefit with dalteparin (VTE rates = 3% vs. 17%; p = 0.011). To measure the economic value of secondary VTE prophylaxis with dalteparin, a patient-level pharmacoeconomic analysis was conducted from the Austrian and French healthcare system perspectives.

METHODS

Chapter 1 Healthcare resource use collected during the CLOT trial was extracted and converted into direct cost estimates. Incremental cost differences between the dalteparin and VKA groups were then combined with health state utilities to measure the cost per quality-adjusted life year (QALY) gained.

RESULTS

The dalteparin group had significantly higher costs than the VKA group in both countries (Austria: dalteparin = €2687 vs. VKA = €2012; France: dalteparin = €2053 vs. VKA = €1352: p < 0.001). However, when the incremental costs were combined with the utility gain, dalteparin had a cost of €6600 and €4900 per QALY gained in Austria and France, respectively. The analyses in patients with renal impairment suggested an even better economic profile, with the cost per QALY gained being less than €4000 in both countries.

CONCLUSIONS

Secondary prophylaxis with dalteparin is a cost-effective alternative to VKA for the prevention of recurrent VTE in patients with cancer.

Dalteparin versus vitamin K antagonists for the prevention of recurrent venous thromboembolism in patients with cancer and renal impairment: a Canadian pharmacoeconomic analysis

Background

Patients with cancer are at increased risk of venous thromboembolism (VTE) and the risk is further elevated after a primary VTE. To reduce the risk of recurrent events, extended prophylaxis with vitamin K antagonists (VKA) is available for use. However, in a large randomized trial (Comparison of Low-Molecular-Weight Heparin versus Oral Anticoagulant Therapy for the Prevention of Recurrent Venous Thromboembolism in Patients with Cancer [CLOT]; Lee et al), extended duration dalteparin reduced the relative risk of recurrent VTE by 52% compared to VKA (p=0.002). A recent subgroup analysis of patients with moderate-to-severe renal impairment also revealed lower absolute VTE rates with dalteparin (3% vs. 17%; p=0.011). To measure the economic value of dalteparin as an alternative to VKA, a patient-level cost utility analysis was conducted from a Canadian perspective.

Methods

Resource use data captured during the CLOT trial were extracted and linked to 2015 Canadian unit cost estimates. Health state utilities were then measured using the Time-Trade-Off technique in 24 randomly selected members of the general Canadian public to estimate the gains in quality-adjusted life years (QALYs).

Results

For the entire CLOT trial population (n=676), the dalteparin group had significantly higher mean costs compared to the VKA group ($Can5,771 vs. $Can2,569; p<0.001). However, the utility assessment revealed that 21 of 24 respondents (88%) selected dalteparin over VKA, with an associated gain of 0.14 (95% confidence interval [CI]: 0.10–0.18) QALYs. When the incremental cost of dalteparin was combined with the QALY gain, dalteparin had a cost of $Can23,100 (95% CI: $Can19,200–$Can25,800) per QALY gained. The analysis in patients with renal impairment suggested even better economic value with the cost per QALY gained being <$14,000.

Conclusion

Extended duration dalteparin is a cost-effective alternative to VKA for the prevention of recurrent VTE in patients with cancer, especially in those with renal impairment.

Increasing the magnetic helicity content of a plasma by pulsing a magnetized source

By operating a magnetized coaxial gun in a pulsed mode it is possible to produce large voltage pulses of duration approximately 500 mus while reaching a few kV, giving a discrete input of helicity into a spheromak. In the sustained spheromak physics experiment (SSPX), it is observed that pulsing serves to nearly double the stored magnetic energy and double the temperature. We discuss these results by comparison with 3D MHD simulations of the same phenomenon.

Low-molecular-weight heparins for the prevention of recurrent venous thromboembolism in patients with cancer: A systematic literature review of efficacy and cost-effectiveness

Background

Patients with cancer have an elevated risk of venous thromboembolism. Importantly, patients with cancer, who have metastatic disease, renal insufficiency, or are receiving anticancer therapy, have an even higher risk of a recurrent event. Similarly, the risk of recurrent venous thromboembolism is higher than the risk of an initial event. To reduce the risk, extended duration of prophylaxis for up to six months with low-molecular-weight heparins such as dalteparin, enoxaparin, nadroparin, and tinzaparin is recommended by international guidelines. In this paper, the clinical and economic literature is reviewed to provide evidenced based recommendations based on clinical benefit and economic value.

Methods

A systematic review of major databases was conducted from January 1996 to October 2016 for randomized controlled trials evaluating the four distinct low-molecular-weight heparins against a vitamin K antagonists control group for the prevention of recurrent venous thromboembolism in patients with active cancer. This was then followed by the application of the National Institute of Health and Clinical Excellence guidance to assess the quality of all trials that met the inclusion criteria. Finally, the cost-effectiveness literature supporting the value proposition of each product was reviewed.

Results

Six randomized trials met the inclusion criteria. There were one, two, and three trials that compared dalteparin, tinzaparin, and enoxaparin to a vitamin K antagonists control group. However, there were no trials for nadroparin in the setting of secondary venous thromboembolism prevention. In addition, only the dalteparin and one of the tinzaparin trials were of high quality and adequately powered. Of the two studies, only the dalteparin trial reported a statistically significant benefit in terms of venous thromboembolism absolute risk reduction when compared to a vitamin K antagonists control group (HR = 0.48; p = 0.002). In addition, there was robust pharmacoeconomic data from Canada, the Netherlands, France, and Austria supporting the cost-effectiveness of dalteparin for this indication. There were no such studies for any of the other agents.

Conclusions

The totality of high-quality clinical and cost-effectiveness data supports the use of dalteparin over other low-molecular-weight heparins for preventing recurrent venous thromboembolism in patients with cancer.

Interactive or tailored digital interventions to increase uptake in cervical, breast, and colorectal cancer screening to reduce health inequity: a systematic review

BACKGROUND AND OBJECTIVES

Significant health inequities exist in screening uptake for certain types of cancer. The review question was to identify and describe interactive, tailored digital, computer, and web-based interventions to reduce health inequity in cancer screening and review the effectiveness of such interventions in increasing screening rates versus usual care.

METHODS

We searched four medical literature databases for randomized control trials (RCTs) published until 12 January 2023 that evaluated interventions aimed at increasing the percentage of breast, prostate, cervical, or colorectal cancer screening uptake. Meta-analysis was not conducted due to heterogeneity among studies.

RESULTS

After screening 4200 titles and abstracts, 17 studies were included. Studies focused on colorectal ( n  = 10), breast ( n  = 4), cervical ( n  = 2), and prostate ( n  = 1) cancer screening. All were based in the USA except two. Most studies focused on ethnicity/race, while some included low-income populations. Intervention types were heterogeneous and used computer programs, apps, or web-based methods to provide tailored or interactive information to participants about screening risks and options. Some studies found positive effects for increasing cancer screening uptake in the intervention groups compared to usual care, but results were heterogeneous.

CONCLUSION

Interventions that use individual and cultural tailoring of cancer screening educational material should be further developed and investigated outside of the USA. Designing effective digital intervention strategies, with components that can be adapted to remote delivery may be an important strategy for reducing health inequities in cancer screening during the coronavirus disease 2019 pandemic.

Economic Analysis Comparing Dalteparin to Vitamin K Antagonists to Prevent Recurrent Venous Thromboembolism in Patients With Cancer Having Renal Impairment

BACKGROUND

In a randomized trial (ie, Comparison of Low-Molecular-Weight Heparin versus Oral Anticoagulant Therapy for the Prevention of Recurrent Venous Thromboembolism in Patients with Cancer [CLOT]) that evaluated secondary prophylaxis of recurrent venous thromboembolism (VTE) in patients with cancer, dalteparin reduced the relative risk by 52% compared to oral vitamin K antagonists (VKAs; hazard ratio = 0.48, P = .002). A recent subgroup analysis in patients with moderate to severe renal impairment also revealed lower absolute VTE rates with dalteparin (3% vs 17%; P = .011). To measure the economic value of dalteparin in these populations, a pharmacoeconomic analysis was conducted from the Dutch health-care system perspective.

METHODS

Resource utilization data contained within the CLOT trial database were extracted and converted into direct cost estimates. Univariate analysis was then conducted to compare the total cost of therapy between patients randomized to dalteparin or VKA therapy. Health state utilities were then measured in 24 members of the general public using the time trade-off technique.

RESULTS

When all of the cost components were combined for the entire population (n = 676), the dalteparin group had significantly higher overall costs than the VKA control group (dalteparin = €2375 vs VKA = €1724; P < .001). However, dalteparin was associated with a gain of 0.14 (95% confidence interval [CI]: 0.10-0.18) quality-adjusted life years (QALYs) over VKA. When the incremental cost was combined with the utility gain, dalteparin had a cost of €4,697 (95% CI: €3824-€4951) per QALY gained.

CONCLUSION

Secondary prophylaxis with dalteparin is a cost-effective alternative to VKA for the prevention of recurrent VTE in patients with cancer.