The JUMPFOOD study: additional effect of hydrolyzed collagen and vitamin C to exercise treatment for patellar tendinopathy (jumper's knee) in athletes-study protocol for a double-blind randomized controlled trial.

BACKGROUND: Patellar tendinopathy (PT) is a common problem in jumping athletes. Management can be challenging and treatment outcome is not always successful. In combination with tendon loading exercises, hydrolyzed collagen/vitamin C supplementation appears to have a promising effect on the recovery of tendinopathy. The aim of this study is to evaluate whether the use of oral supplementation of hydrolyzed collagen and vitamin C in combination with progressive tendon loading exercises (PTLE) is superior to PTLE and placebo on VISA-P score (which rates pain, function, sports participation) after 24 weeks for athletes with PT. METHODS: The JUMPFOOD study is a double-blinded, two-armed randomized controlled trial, in which the effectiveness of oral supplementation of hydrolyzed collagen/vitamin C combined with PTLE compared to PTLE with placebo on pain and recovery of function in athletes with PT will be investigated. Seventy-six athletes aged 16-40 years, with symptoms of PT for at least 12 weeks, who play sports at least once a week will be included. All participants will receive education, advice with regard to load management and a PTLE program according to the Dutch guidelines for anterior knee pain. In addition, the intervention group will receive daily 10 g hydrolyzed collagen and 40 mg vitamin C supplementation for 24 weeks whereas the control group receives 10 g maltodextrin placebo supplementation. Measurements will take place at baseline and at 12 and 24 weeks' follow-up. Primary outcome is the VISA-P score, which evaluates pain, function, and sports participation. For secondary outcome measures, data with regard to pain during functional tests, flexibility measurements, blood withdrawals, imaging characteristics of the tendon, and health questionnaires will be collected. During the follow-up period, participants will register sports participation, amount of training and tendon load, pain during sports, co-medication, and side-effects in a digital weekly diary. DISCUSSION: The JUMPFOOD study is the first large RCT to study the effectiveness of hydrolyzed collagen/vitamin C supplementation in combination with the PTLE program in athletes with patellar tendinopathy. If supplementation of collagen/vitamin C appears to be effective, this treatment can be implemented in daily sports medicine practice to improve the treatment outcome of patients with PT. TRIAL REGISTRATION: ClinicalTrials.gov NCT05407194. Registered on 7 June 2022.

[A multi-centre ROM study of the Guideline-Informed Treatment for Personality Disorders]. / Een ROM-studie van de Guideline-Informed Treatment for Personality Disorders in vier behandelcentra.

BACKGROUND: The Guideline-Informed Treatment for Personality Disorders (GIT-PD) is widely used in the Netherlands and Belgium in the care of people with personality disorders. To date, no evidence existed for the possible efficacy of this treatment framework.  METHOD: In an observational cohort study in four institutions, based on Routine Outcome Monitoring-data, improvements in symptom burden (BSI/OQ-45) and personality functioning (SIPP-SF) in 470 patients were examined.  RESULTS: Significant improvements were observed in each of the settings for both symptom burden and personality functioning. Effect sizes for improvement in overall symptom burden ranged from d = 0.55 to 1.05.  CONCLUSION: Treatment outcomes for GIT-PD are in line with treatment outcomes also seen for specialized treatments for personality disorders in similar practice studies. Possible differences between settings could be related to the intensity, structure and coherence of the GIT-PD program in question. .

Impact of pulmonary infarction in pulmonary embolism on presentation and outcomes.

BACKGROUND: Pulmonary infarction (PI) is relatively common in pulmonary embolism (PE). The association between PI and persistent symptoms or adverse events is largely unknown. AIM: To evaluate the predictive value of radiological PI signs at acute PE diagnosis on 3-month outcomes. METHODS: We studied a convenience cohort with computed tomography pulmonary angiography (CTPA)-confirmed PE for whom extensive 3-month follow-up data were available. The CTPAs were re-evaluated for signs of suspected PI. Associations with presenting symptoms, adverse events (recurrent thrombosis, PE-related readmission and mortality) and self-reported persistent symptoms (dyspnea, pain and post-PE functional impairment) at 3-month follow-up were investigated using univariate Cox regression analysis. RESULTS: At re-evaluation of the CTPAs, 57 of 99 patients (58 %) had suspected PI, comprising a median of 1 % (IQR 1-3) of total lung parenchyma. Patients with suspected PI more often presented with hemoptysis (11 % vs. 0 %) and pleural pain (OR 2.7, 95%CI 1.2-6.2), and with more proximal PE on CTPA (OR 1.6, 95%CI 1.1-2.4) than patients without suspected PI. There was no association with adverse events, persistent dyspnea or pain at 3-month follow-up, but signs of PI predicted more functional impairment (OR 3.03, 95%CI 1.01-9.13). Sensitivity analysis with the largest infarctions (upper tertile of infarction volume) yielded similar results. CONCLUSIONS: PE patients radiologically suspected of PI had a different clinical presentation than patients without those signs and reported more functional limitations after 3 months of follow-up, a finding that could guide patient counselling.

[How evidence-based is the guideline-informed treatment for personality disorders (GIT-PD)?] / Hoe bewezen effectief is de guideline-informed treatment for personality disorders (GIT-PD)?

BACKGROUND: The guideline-informed treatment for personality disorders (GIT-PD) was developed as an alternative to the specific treatments for personality disorders. Even though this form of treatment is widely used in health care and has been included in the Health Care Standard for Personality Disorders, its scientific evidence remains unclear. AIM: To review the indirect evidence for GIT-PD and compare it with the evidence for specific treatments. METHOD: Literature review including reviews and meta-analyses in the field of personality disorders. RESULTS: Although there is increasing evidence for specific treatments, the amount of studies remains limited and the quality of the evidence is rather low. There are indications that specific treatments are poorly implemented in clinical practice, which may detract from their efficacy. There is no clear evidence that specific treatments are on average no more effective than well-designed generic treatments that are similar to GIT-PD. There is considerable evidence for the role of the common factors on which GIT-PD is based. CONCLUSION: There is indirect evidence for the efficacy of GIT-PD. Good care on a broad scale needs both specific and generic forms of treatment, whereby the most relevant question becomes how clients can be optimally allocated to both forms of treatment.

Elucidation of the Genetic Cause in Dutch Limb Girdle Muscular Dystrophy Families: A 27-Year's Journey.

BACKGROUND: A Dutch cohort of 105 carefully selected limb girdle muscular dystrophy (LGMD) patients from 68 families has been subject to genetic testing over the last 20 years. After subsequent targeted gene analysis around two thirds (45/68) of the families had received a genetic diagnosis in 2013. OBJECTIVE: To describe the results of further genetic testing in the remaining undiagnosed limb girdle muscular dystrophy families in this cohort. METHODS: In the families of the cohort for whom no genetic diagnosis was established (n = 23) further testing using Sanger sequencing, next generation sequencing with gene panel analysis or whole-exome sequencing was performed. In one case DNA analysis for facioscapulohumeral dystrophy type 1 was carried out. RESULTS: In eight families no additional genetic tests could be performed. In 12 of the remaining 15 families in which additional testing could be performed a genetic diagnosis was established: two LGMDR1 calpain3-related families with CAPN3 mutations, one LGMDR2 dysferlin-related family with DYSF mutations, three sarcoglycanopathy families (LGMDR3-5 α-, ß- and γ-sarcoglycan-related) with SGCA/SGCB/SGCG mutations, one LGMDR8 TRIM 32-related family with TRIM32 mutations, two LGMDR19 GMPPB-related families with GMPPB mutations, one family with MICU1-related myopathy, one family with FLNC-related myopathy and one family with facioscapulohumeral dystrophy type 1. At this moment a genetic diagnosis has been made in 57 of the 60 families of which DNA was available (95%). CONCLUSION: A genetic diagnosis is obtained in 95% of the families of the original Dutch LGMD cohort of which DNA was available.

Clinical and computed tomography characteristics of COVID-19 associated acute pulmonary embolism: A different phenotype of thrombotic disease?

INTRODUCTION: COVID-19 infections are associated with a high prevalence of venous thromboembolism, particularly pulmonary embolism (PE). It is suggested that COVID-19 associated PE represents in situ immunothrombosis rather than venous thromboembolism, although the origin of thrombotic lesions in COVID-19 patients remains largely unknown. METHODS: In this study, we assessed the clinical and computed tomography (CT) characteristics of PE in 23 consecutive patients with COVID-19 pneumonia and compared these to those of 100 consecutive control patients diagnosed with acute PE before the COVID-19 outbreak. Specifically, RV/LV diameter ratio, pulmonary artery trunk diameter and total thrombus load (according to Qanadli score) were measured and compared. RESULTS: We observed that all thrombotic lesions in COVID-19 patients were found to be in lung parenchyma affected by COVID-19. Also, the thrombus load was lower in COVID-19 patients (Qanadli score -8%, 95% confidence interval [95%CI] -16 to -0.36%) as was the prevalence of the most proximal PE in the main/lobar pulmonary artery (17% versus 47%; -30%, 95%CI -44% to -8.2). Moreover, the mean RV/LV ratio (mean difference -0.23, 95%CI -0.39 to -0.07) and the prevalence of RV/LV ratio >1.0 (prevalence difference -23%, 95%CI -41 to -0.86%) were lower in the COVID-19 patients. CONCLUSION: Our findings therefore suggest that the phenotype of COVID-19 associated PE indeed differs from PE in patients without COVID-19, fuelling the discussion on its pathophysiology.

Management and treatment of deep vein thrombosis in special populations.

INTRODUCTION: Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third most frequent cardiovascular disease besides myocardial infarction and stroke. Because DVT may cause life-threatening conditions, treatment should be started as soon as possible. This comprises certain challenges in special populations. Areas covered: In cancer-associated VTE, current treatment is different from non-cancer VTE due to disease-related interventions and higher bleeding risks. In the treatment of patients with extensive DVT, the role of catheter-directed thrombolysis has been investigated in two randomized trials, but results do not yield a recommendation for standard thrombolysis. The diagnosis of suspected recurrent DVT is especially challenging in case of ipsilateral DVT. Treatment strategies in recurrent DVT are dependent on the case and on particular risk factors. Also discussed is the therapy for DVT in pregnant women, which is more complex as a result of anticoagulants crossing the placenta. Expert commentary: DVT treatment in special populations poses special challenges due to high thrombotic and bleeding risk. This will be discussed in more detail in this review.

Does Natural Mentoring Matter? A Multilevel Meta-analysis on the Association Between Natural Mentoring and Youth Outcomes.

In this meta-analytic review, we examined the relation between natural mentoring and youth outcomes in four domains: academic and vocational functioning, social-emotional development, physical health, and psychosocial problems. Natural mentoring relationships are thought to foster positive youth development and buffer against the risks associated with the tumultuous years of adolescence. Two separate meta-analyses were conducted on the presence of a natural mentor and the quality of the natural mentoring relationship, including thirty studies from 1992 to present. The findings indicated that the presence of a natural mentor was significantly associated with positive youth outcomes (r = .106). A larger effect size was found for the quality of the natural mentoring relationship in terms of relatedness, social support, and autonomy support (r = .208). The largest effect sizes were found for social-emotional development and academic and vocational functioning. Risk-status (e.g., teenage mothers, homeless youth, youth in foster care, and youth of alcoholic parents) did not moderate the relation between presence and quality of natural mentoring relationships and youth outcomes, which may indicate that natural mentors are generally beneficial for all youth regardless of risk-status. Implications for theory and practice concerning the quality of the natural mentoring relationship are discussed.

Smooth at one end and rough at the other: influence of object texture on grasping behaviour.

When picking up objects using a pinch grip, there are usually numerous places at which one could place the thumb and index finger. Yet, people seem to consistently place them at or close to the centre of mass (COM), presumably to minimize torque and therefore the required grip force. People also prefer to grasp objects by parallel surfaces and ones with higher friction coefficients (rough surfaces), to prevent the object from slipping when they lift it. Here, we examine the trade-off between friction and COM. Participants were asked to grasp and lift aluminium bars of which one end was polished and therefore smooth and the other was rough. Their finger positions were recorded to determine how they grasped the objects. The bars were oriented horizontally in the frontal plane, with the centre aligned with the participants' body midline. The bars varied in the horizontal offset between the COM and the edge of the rough region. The offset could be 0, 1 or 2 cm. We expected participants to grasp closer to the rough area than the centre of the bar. Completely rough bars and completely smooth bars served as control conditions. The slipperiness of the surface that was grasped affected the height of the grasping points, indicating that participants adjusted their grasping behaviour to the slipperiness of the surface. However, the tendency to grasp closer to the rough area was minimal. This shows that the judged COM largely determines how an object is grasped. Friction has very limited influence.

Muscle imaging in inherited and acquired muscle diseases.

In this review we discuss the use of conventional (computed tomography, magnetic resonance imaging, ultrasound) and advanced muscle imaging modalities (diffusion tensor imaging, magnetic resonance spectroscopy) in hereditary and acquired myopathies. We summarize the data on specific patterns of muscle involvement in the major categories of muscle disease and provide recommendations on how to use muscle imaging in this field of neuromuscular disorders.

What influences the decision to participate in colorectal cancer screening with faecal occult blood testing and sigmoidoscopy?

INTRODUCTION: Uptake is an important determinant of the effectiveness of population-based screening. Uptake of colorectal cancer (CRC) screening generally remains sub-optimal. AIM: To determine factors influencing the decision whether to participate or not among individuals invited for faecal occult blood test (FOBT) or flexible sigmoidoscopy (FS) screening. METHODS: A questionnaire was sent to a stratified random sample of individuals aged 50-74, previously invited for a randomised CRC screening trial offering FOBT or FS, and a reference group from the same population not previously invited (screening naïve group). The questionnaire assessed reasons for (non)-participation, individuals' characteristics associated with participation, knowledge, attitudes and level of informed choice. RESULTS: The response rate was 75% (n=341/452) for CRC screening participants, 21% (n=676/3212) for non-participants and 38% (n=192/500) for screening-naïve individuals. The main reasons for FOBT and FS participation were acquiring certainty about CRC presence and possible early CRC detection. Anticipated regret and positive attitudes towards CRC screening were strong predictors of actual participation and intention to participate in a next round. The main reason for non-participation in FOBT screening was lack of abdominal complaints. Non-participation in FS screening was additionally influenced by worries about burden. Eighty-one percent of participants and 12% of non-participants made an informed choice on participation. CONCLUSION: Only 12% of non-participants made an informed choice not to participate. These results imply that governments and/or organizations offering screening should focus on adequately informing and educating target populations about the harms and benefits of CRC screening. This may impact uptake of CRC screening.

Time requirements and health effects of participation in colorectal cancer screening with colonoscopy or computed tomography colonography in a randomized controlled trial.

BACKGROUND AND STUDY AIMS: Time limitations and unwanted health effects may act as barriers to participation in colorectal cancer (CRC) screening. The aim of the study was to measure the time requirements and health effects of colonoscopy and computed tomography colonography (CTC) screening. PATIENTS AND METHODS: This was a prospective diary study in a consecutive sample within a randomized controlled CRC screening trial, comparing primary colonoscopy and CTC screening for average-risk individuals aged 50 - 74 years. The diary ended when all screening-related complaints had passed. RESULTS: The diary was returned by 75 % (241/322) of colonoscopy and 75 % (127/170) of CTC screenees. The median interval between leaving home and returning from the examination was longer for colonoscopy (4 hours and 18 minutes [4:18], interquartile range [IQR] 3:30 - 5:00) than for CTC (2:30 hours, IQR 2:06 - 3:00; P < 0.001). Similarly, the time to return to routine activities was longer after colonoscopy (3:54 hours, IQR 1:48 - 15:00) than after CTC (1:36 hours, IQR 0:54 - 4:42). The duration of screening-related symptoms after the examination was shorter for colonoscopy (11:00 hours, IQR 2:54 - 20:00) than for CTC (22:00 hours; IQR 5:30 - 47:00; P < 0.001). Abdominal complaints were reported more frequently after CTC. Anxiety, pain, and quality of life worsened during the screening process, with no differences between the two examinations. CONCLUSIONS: Compared with colonoscopy, CTC screening required less time and allowed screenees to return to their daily activities more quickly. In contrast, CTC was associated with a twofold longer duration of screening-related symptoms. Feelings of anxiety, pain, and quality of life scores were similar during colonoscopy and CTC screening. These results should be incorporated into cost-effectiveness analyses of CRC screening techniques.

Quality of life in participants of a CRC screening program.

BACKGROUND: Little is known about the effect of participating in a colorectal cancer (CRC) screening programme on quality of life (QOL), neither for participants with a negative nor for those with a positive test result. These findings, however, are important to evaluate the impact of CRC screening. METHODS: Participants from CRC screening trials were sent a questionnaire, which included validated measures on generic health-related QOL, generic anxiety and screen-specific anxiety. Both faecal immunochemical test (FIT) and flexible sigmoidoscopy (FS) participants, either with negative or positive test results, were addressed. RESULTS: The response rate was 73% (1289 out of 1772) for FIT and 78% (536 out of 689) for FS participants, with mean ages varying from 63-66 years. Positive FIT participants had worse physical (PCS-12, 47.1 vs 48.3, P=0.02), but equal mental QOL scores (MCS-12, 51.1 vs 51.6, P=0.26). Positive and negative FS participants had similar QOL scores. Both FIT and FS participants with a positive test result reported more screen-specific anxiety than negative FIT and FS participants. Positive and negative FS participants had similar generic anxiety scores. CONCLUSION: Our findings indicate that the burden of participating in CRC screening may be limited. Conducting a prospective study to confirm these results is recommended.

Preferences for colorectal cancer screening strategies: a discrete choice experiment.

BACKGROUND: Guidelines underline the role of individual preferences in the selection of a screening test, as insufficient evidence is available to recommend one screening test over another. We conducted a study to determine the preferences of individuals and to predict uptake for colorectal cancer (CRC) screening programmes using various screening tests. METHODS: A discrete choice experiment (DCE) questionnaire was distributed among naive subjects, yet to be screened, and previously screened subjects, aged 50-75 years. Subjects were asked to choose between scenarios on the basis of faecal occult blood test (FOBT), flexible sigmoidoscopy (FS), total colonoscopy (TC) with various test-specific screening intervals and mortality reductions, and no screening (opt-out). RESULTS: In total, 489 out of 1498 (33%) screening-naïve subjects (52% male; mean age+/-s.d. 61+/-7 years) and 545 out of 769 (71%) previously screened subjects (52% male; mean age+/-s.d. 61+/-6 years) returned the questionnaire. The type of screening test, screening interval, and risk reduction of CRC-related mortality influenced subjects' preferences (all P<0.05). Screening-naive and previously screened subjects equally preferred 5-yearly FS and 10-yearly TC (P=0.24; P=0.11), but favoured both strategies to annual FOBT screening (all P-values <0.001) if, based on the literature, realistic risk reduction of CRC-related mortality was applied. Screening-naive and previously screened subjects were willing to undergo a 10-yearly TC instead of a 5-yearly FS to obtain an additional risk reduction of CRC-related mortality of 45% (P<0.001). CONCLUSION: These data provide insight into the extent by which interval and risk reduction of CRC-related mortality affect preferences for CRC screening tests. Assuming realistic test characteristics, subjects in the target population preferred endoscopic screening over FOBT screening, partly, due to the more favourable risk reduction of CRC-related mortality by endoscopy screening. Increasing the knowledge of potential screenees regarding risk reduction by different screening strategies is, therefore, warranted to prevent unrealistic expectations and to optimise informed choice.

What determines individuals' preferences for colorectal cancer screening programmes? A discrete choice experiment.

INTRODUCTION: In many countries uptake of colorectal cancer (CRC) screening remains low. AIM: To assess how procedural characteristics of CRC screening programmes determine preferences for participation and how individuals weigh these against the perceived benefits from participation in CRC screening. METHODS: A discrete choice experiment was conducted among subjects in the age group of 50-75 years, including both screening-naïve subjects and participants of a CRC screening programme. Subjects were asked on their preferences for aspects of CRC screening programmes using scenarios based on pain, risk of complications, screening location, preparation, duration of procedure, screening interval and risk reduction of CRC-related death. RESULTS: The response was 31% (156/500) for screening-naïve and 57% (124/210) for CRC screening participants. All aspects proved to significantly influence the respondents' preferences. For both groups combined, respondents required an additional relative risk reduction of CRC-related death by a screening programme of 1% for every additional 10 min of duration, 5% in order to expose themselves to a small risk of complications, 10% to accept mild pain, 10% to undergo preparation with an enema, 12% to use 0.75l of oral preparation combined with 12h fasting and 32% to use an extensive bowel preparation. Screening intervals shorter than 10 years were significantly preferred to a 10-year screening interval. CONCLUSION: This study shows that especially type of bowel preparation, risk reduction of CRC related death and length of screening interval influence CRC screening preferences. Furthermore, improving awareness on CRC mortality reduction by CRC screening may increase uptake.

Platform accelerations of three different whole-body vibration devices and the transmission of vertical vibrations to the lower limbs.

Physical whole-body vibration (WBV) exercises become available at various levels of intensity. In a first series of measurements, we investigated 3-dimensional platform accelerations of three different WBV devices without and with three volunteers of different weight (62, 81 and 100 kg) in squat position (150 degrees knee flexion). The devices tested were two professional devices, the PowerPlate and the Galileo-Fitness, and one home-use device, the PowerMaxx. In a second series of measurements, the transmission of vertical platform accelerations of each device to the lower limbs was tested in eight healthy volunteers in squat position (100 degrees knee flexion). The first series showed that the platforms of two professional devices vibrated in an almost perfect vertical sine wave at frequencies between 25-50 and 5-40 Hz, respectively. The platform accelerations were slightly influenced by body weight. The PowerMaxx platform mainly vibrated in the horizontal plane at frequencies between 22 and 32 Hz, with minimal accelerations in the vertical direction. The weight of the volunteers reduced the platform accelerations in the horizontal plane but amplified those in the vertical direction about eight times. The vertical accelerations were highest in the Galileo (approximately 15 units of g) and the PowerPlate (approximately 8 units of g) and lowest in the PowerMaxx (approximately 2 units of g). The second series showed that the transmission of vertical accelerations at a common preset vibration frequency of 25 Hz were largest in the ankle and that transmission of acceleration reduced approximately 10 times at the knee and hip. We conclude that large variation in 3-dimensional accelerations exist in commercially available devices. The results suggest that these differences in mechanical behaviour induce variations in transmissibility of vertical vibrations to the (lower) body.

Voluntary control and the dynamics of perceptual bi-stability.

Voluntary control and conscious perception seem to be related: when we are confronted with ambiguous images we are in some cases and to some extent able to voluntarily select a percept. However, to date voluntary control has not been used in neurophysiological studies on the correlates of conscious perception, presumably because the dynamic of perceptual reversals was not suitable. We exposed the visual system to four ambiguous stimuli that instigate bi-stable perception: slant rivalry, orthogonal grating rivalry, house-face rivalry, and Necker cube rivalry. In the preceding companion paper [van Ee, R. (2005). Dynamics of perceptual bi-stability for stereoscopic slant rivalry and a comparison with grating, house-face, and Necker cube rivalry. Vision Research] we focussed on the temporal dynamics of the perceptual reversals. Here we examined the role of voluntary control in the dynamics of perceptual reversals. We asked subjects to attempt to hold percepts and to speed-up the perceptual reversals. The investigations across the four stimuli revealed qualitative similarities concerning the influence of voluntary control on the temporal dynamics of perceptual reversals. We also found differences. In comparison to the other rivalry stimuli, slant rivalry exhibits: (1) relatively long percept durations; (2) a relatively clear role of voluntary control in modifying the percept durations. We advocate that these aspects, alongside with its metrical (quantitative) aspects, potentially make slant rivalry an interesting tool in studying the neural underpinnings of visual awareness.

NaDNA-bipyridyl-(ethylenediamine)platinum (II) complex: structure in oriented wet-spun films and fibers.

Complexes of NaDNA with bipyridyl-(ethylenediamine)platinum(II) (abbreviated [(bipy)Pt(en)](2+)) in solid, oriented films, prepared with a wet-spinning method, have been studied using x-ray diffraction, elastic neutron scattering, two-dimensional magic-angle-spinning nuclear magnetic resonance (NMR), infrared (IR) linear dichroism, and IR absorption. All of these experiments indicate that the DNA in this complex is in the B conformation. The neutron diffraction experiments reveal that the rise per residue is 3.31 A, indicating that the [(bipy)Pt(en)](2+) molecular ion causes a small distortion of the B conformation. The neutron data in the direction perpendicular to the helical axis are consistent with a centered orthorhombic unit cell with a=22.65 A and b=32.2 A. The NMR and IR experiments show that the orientation of phosphate groups in the DNA small middle dot[(bipy)Pt(en)](2+) complex is the same as that observed for pure DNA in the B conformation. The IR experiments also show that the [(bipy)Pt(en)](2+) molecular ion stabilizes the B conformation of DNA down to 59% relative humidity, a low water activity. Mechanochemical experiments on wet-spun NaDNA fibers in 68% ethanol with and without [(bipy)Pt(en)](2+) reveal a 9% elongation of the DNA fibers as the complex is formed.

BII nucleotides in the B and C forms of natural-sequence polymeric DNA: A new model for the C form of DNA.

A combination of solid-state (31)P and (13)C NMR, X-ray diffraction, and model building is used to show that the B and C forms of fibrous macromolecular DNA consist of two distinct nucleotide conformations, which correspond closely to the BI and BII nucleotide conformations known from oligonucleotide crystals. The proportion of the BII conformation is higher in the C form than in the B form. We show structural models for a 10(1) double helix involving BI nucleotides and a 9(1) double helix involving BII nucleotides. The 10(1) BI model is similar to a previous model of B-form DNA, while the 9(1) BII model is novel. The BII model has a very deep and narrow minor groove, a shallow and wide major groove, and highly inclined bases. This work shows that the B to C transition in fibers corresponds to BI to BII conformational changes of the individual nucleotides.