Reproducibility and Repeatability in Focus: Evaluating LVEF Measurements with 3D Echocardiography by Medical Technologists.

Three-dimensional echocardiography (3DE) is currently the preferred method for monitoring left ventricular ejection fraction (LVEF) in cancer patients receiving potentially cardiotoxic anti-neoplastic therapy. In Denmark, however, the traditional standard for LVEF monitoring has been rooted in nuclear medicine departments utilizing equilibrium radionuclide angiography (ERNA). Although ERNA remains a principal modality, there is an emerging trend towards the adoption of echocardiography for this purpose. Given this context, assessing the reproducibility of 3DE among non-specialized medical personnel is crucial for its clinical adoption in such departments. To assess the feasibility of 3DE for LVEF measurements by technologists, we evaluated the repeatability and reproducibility of two moderately experienced technologists. They performed 3DE on 12 volunteers over two sessions, with a collaborative review of the results from the first session before the second session. Two-way intraclass correlation values increased from 0.03 to 0.77 across the sessions. This increase in agreement was mainly due to the recognition of false low measurements. Our findings underscore the importance of incorporating reproducibility exercises in the context of 3DE, especially when operated by technologists. Additionally, routine control of the acquisitions by physicians is deemed necessary. Ensuring these hurdles are adequately managed enables the adoption of 3DE for LVEF measurements by technologists.

Empagliflozin to elderly and obese patients with increased risk of developing heart failure: Study protocol for the Empire Prevent trial program.

INTRODUCTION: Sodium-glucose cotransporter 2 (SGLT2) inhibitors have previously demonstrated cardioprotective properties in patients with type 2 diabetes, suggesting a preventive effect on heart failure (HF). The Empire Prevent trial program investigates the therapeutic potential for HF prevention by evaluating the cardiac, metabolic, and renal effects of the SGLT2 inhibitor empagliflozin in patients with increased risk of developing HF, but without diabetes or established HF. METHODS: The Empire Prevent trial program is an investigator-initiated, double-blind, randomized clinical trial program including elderly and obese patients (60-84 years, body mass index >28 kg/m2) with at least one manifestation of hypertension, cardiovascular or chronic kidney disease, but no history of diabetes or HF. The aims are to investigate the effects of empagliflozin on 1) physical capacity and left ventricular and atrial structural changes with peak oxygen consumption and left ventricular mass as primary endpoints (Empire Prevent Cardiac), and 2) cardiac-adipose tissue interaction and volume homeostasis with primary endpoints of changes in epicardial adipose tissue and estimated extracellular volume (Empire Prevent Metabolic). At present, 138 of 204 patients have been randomized in the Empire Prevent trial program. Patients are randomized 1:1 to 180 days treatment with empagliflozin 10 mg daily or placebo, while undergoing a comprehensive examination program at baseline and follow-up. DISCUSSION: The Empire Prevent trial program will mark the first step towards elucidating the potential of SGLT2 inhibition for HF prevention in an outpatient setting in elderly and obese patients with increased risk of developing HF, but with no history of diabetes or established HF. Furthermore, the Empire Prevent trial program will supplement the larger event-driven trials by providing mechanistic insights to the beneficial effects of SGLT2 inhibition. TRIAL REGISTRATION: Both parts of the trial program have been registered on September 13th 2021 (Clinical Trial Registration numbers: NCT05084235 and NCT05042973) before enrollment of the first patient. All patients will provide oral and written informed consent. The trial is approved by The Regional Committee on Health Research Ethics and the Danish Medicines Agency. Data will be disseminated through scientific meetings and peer-reviewed journals irrespective of outcome.

Dopamine Synthesis Capacity and GABA and Glutamate Levels Separate Antipsychotic-Naïve Patients With First-Episode Psychosis From Healthy Control Subjects in a Multimodal Prediction Model.

Background: Disturbances in presynaptic dopamine activity and levels of GABA (gamma-aminobutyric acid) and glutamate plus glutamine collectively may have a role in the pathophysiology of psychosis, although separately they are poor diagnostic markers. We tested whether these neurotransmitters in combination improve the distinction of antipsychotic-naïve patients with first-episode psychosis from healthy control subjects. Methods: We included 23 patients (mean age 22.3 years, 9 male) and 20 control subjects (mean age 22.4 years, 8 male). We determined dopamine metabolism in the nucleus accumbens and striatum from 18F-fluorodopa (18F-FDOPA) positron emission tomography. We measured GABA levels in the anterior cingulate cortex (ACC) and glutamate plus glutamine levels in the ACC and left thalamus with 3T proton magnetic resonance spectroscopy. We used binominal logistic regression for unimodal prediction when we modeled neurotransmitters individually and for multimodal prediction when we combined the 3 neurotransmitters. We selected the best combination based on Akaike information criterion. Results: Individual neurotransmitters failed to predict group. Three triple neurotransmitter combinations significantly predicted group after Benjamini-Hochberg correction. The best model (Akaike information criterion 48.5) carried 93.5% of the cumulative model weight. It reached a classification accuracy of 83.7% (p = .003) and included dopamine synthesis capacity (Ki4p) in the nucleus accumbens (p = .664), GABA levels in the ACC (p = .019), glutamate plus glutamine levels in the thalamus (p = .678), and the interaction term Ki4p × GABA (p = .016). Conclusions: Our multimodal approach proved superior classification accuracy, implying that the pathophysiology of patients represents a combination of neurotransmitter disturbances rather than aberrations in a single neurotransmitter. Particularly aberrant interrelations between Ki4p in the nucleus accumbens and GABA values in the ACC appeared to contribute diagnostic information.

Effects of an early intervention with Hyperbaric Oxygen Treatment on arm lymphedema and quality of life after breast cancer-an explorative clinical trial.

PURPOSE: Lymphedema (LE) is a common complication after breast cancer treatment, which negatively affects the quality of life (QOL). Hyperbaric Oxygen Treatment (HBOT) is an established treatment for radiation-induced tissue injury, but evidence of effect on breast cancer-related LE is inconclusive. We aimed to explore effects of HBOT on early breast cancer-related LE and the implications for QOL. METHODS: We invited women with breast cancer treated with surgery, axillary dissection and radiotherapy, who had participated in a randomized controlled trial and who presented with LE 1 year after surgery. In a prospective observational study design, change in LE was assessed with perometry, dual-energy X-ray absorptiometry (DXA) and lymphoscintigraphy, and QOL by validated self-report scales. Participants were offered 40 sessions of HBOT on every weekday for 8 weeks and were followed for 6 months. RESULTS: Out of 50 eligible participants, 20 women accepted participation. Nineteen women initiated and completed treatment and follow-up. None of the objective measures of LE severity showed consistent changes during the study period, but participants reported significant improvements in QOL (physical functioning, fatigue, insomnia and breast and arm symptoms), with improvements peaking at 6-month follow-up. CONCLUSION: Participants receiving HBOT experienced improved QOL without consistently significant changes in arm mass, volume or lymphatic drainage. These results call for studies into differential effect in patient sub-groups, and a large-scale, randomized placebo-controlled trial with long-term follow-up to assess the effect of HBOT in patients with soft tissue radiation injuries after breast cancer seems warranted. TRIAL REGISTRATION: Danish Health and Medicines Authority, EUDRACT no. 2015-000,604-25 Ethical committee of the Capitol Region, No. R96-A6604-14-S22.

Changes in quality of life 6 months after parathyroidectomy for primary hyperparathyroidism.

Objective: The extent of symptoms due to primary hyperparathyroidism (PHPT) depends on the population being studied. PHPT is mainly discovered incidentally through routine laboratory findings. Less is known about patient-experienced improvement following successful parathyroidectomy. The aim of our study was to assess the changes in the quality of life (QoL) after successful surgery using an SF-36 questionnaire. Design: This is a prospective cohort study based on questionnaires. Methods: Forty consecutive patients diagnosed with PHPT were prospectively administered an SF-36 questionnaire before and 6 months after successful parathyroidectomy. A subgroup of 18 patients answered the questionnaire at 1 and 3 months after surgery. Successful surgery was based on biochemistry and pathology reports as confirmed by an endocrinologist. Results of each SF-36 subcategory were compared to the results at baseline in order to detect changes in patient-reported QoL after successful surgery. Results: There were significant improvements in six of eight SF-36 subcategories: vitality (P = 0.0001), physical functioning (P = 0.04), general health perception (P = 0.004), physical role functioning (P = 0.04), social role functioning (P = 0.004), and mental health perception (P = 0.0001). Changes appeared within a month after surgery with no further significant changes at later time points. Conclusions: Parathyroidectomy significantly improves QoL as measured by a decrease in SF-36 scores as early as 1 month after successful parathyroidectomy. The SF-36 QoL questionnaire is suitable for monitoring changes in patient well-being after successful parathyroidectomy.

Dopaminergic Activity in Antipsychotic-Naïve Patients Assessed With Positron Emission Tomography Before and After Partial Dopamine D2 Receptor Agonist Treatment: Association With Psychotic Symptoms and Treatment Response.

BACKGROUND: Dopamine activity has been associated with the response to antipsychotic treatment. Our study used a four-parameter model to test the association between the striatal decarboxylation rate of 18F-DOPA to 18F-dopamine (k3) and the effect of treatment on psychotic symptoms in antipsychotic-naïve patients with first-episode psychosis. We further explored the effect of treatment with a partial dopamine D2 receptor agonist (aripiprazole) on k3 and dopamine synthesis capacity (DSC) determined by the four-parameter model and by the conventional tissue reference method. METHODS: Sixty-two individuals (31 patients and 31 control subjects) underwent 18F-DOPA positron emission tomography at baseline, and 15 patients were re-examined after 6 weeks. Clinical re-examinations were completed after 6 weeks (n = 28) and 6 months (n = 15). Symptoms were evaluated with the Positive and Negative Syndrome Scale. RESULTS: High baseline decarboxylation rates (k3) were associated with more positive symptoms at baseline (p < .001) and with symptom improvement after 6 weeks (p = .006). Subregion analyses showed that baseline k3 for the putamen (p = .003) and nucleus accumbens (p = .013) and DSC values for the nucleus accumbens (p = .003) were associated with psychotic symptoms. The tissue reference method yielded no associations between DSC and symptoms or symptom improvement. Neither method revealed any effects of group or treatment on average magnitudes of k3 or DSC, whereas changes in dopamine synthesis were correlated with higher baseline values, implying a potential effect of treatment. CONCLUSIONS: Striatal decarboxylation rate at baseline was associated with psychotic symptoms and treatment response. The strong association between k3 and treatment effect potentially implicate on new treatment strategies.

Enhanced Physiological Stress Response in Patients with Normal Tension Glaucoma during Hypoxia.

PURPOSE: To investigate whether patients with normal tension glaucoma (NTG) show an enhanced stress response to reduced oxygen supply compared to age-matched healthy controls, measured by serum adrenaline and endothelin-1 (ET-1) levels and changes in distal finger temperature. METHODS: A thorough clinical characterization of patients with NTG and age-matched controls was performed prior to inclusion in the study. Twelve patients with NTG and eleven healthy controls met the inclusion criteria and were enrolled in the study. All subjects underwent a two-day investigation. Participants were randomly exposed to either hypoxia or normoxia during the first visit. Hypoxia or normoxia was induced for two hours through a tightly fitting face mask. In addition, the peripheral circulation was assessed with a thermographic camera. Blood samples were obtained before, during, and after hypoxia or normoxia to evaluate systemic stress molecules such as catecholamines and ET-1 levels. RESULTS: In patients with NTG, reduced oxygen supply induced an increase in peripheral blood adrenaline (p < 0.05) and a decrease during recovery (p < 0.01). A difference in distal finger temperature was shown in patients with NTG under hypoxia compared to normoxia (exposure: p < 0.05; recovery: p < 0.05). Hypoxia induced an increase in peripheral blood ET-1 levels in both groups (NTG: p < 0.01; controls: p < 0.05). CONCLUSION: Patients with NTG had an enhanced physiological stress response as a consequence of hypoxia compared with age-matched controls. Although more studies are needed, the present study supports the involvement of vascular risk factors in the pathophysiology of NTG.

Locating hyperfunctioning parathyroid glands using 11C-Choline PET/CT: an inter- and intra-observer variation study.

BACKGROUND: Use of 11C-Choline PET/CT is gaining ground in detecting hyperfunctioning parathyroid glands in primary hyperparathyroidism. The purpose of this study was to evaluate the robustness of 11C-Choline PET/CT by assessing intra- and inter-observer agreement to determine whether the method was reader sensitive and therefore should only be performed at highly specialised sites with a high number of cases. PET/CT images of 40 patients diagnosed with primary hyperparathyroidism were anonymised and evaluated three times by three readers: an expert reader and two non-experts (non-experts were experienced in PET/CT imaging, but not in 11C-Choline PET/CT in the setting of primary hyperparathyroidism). Number of hyperfunctioning parathyroid glands, location relative to the thyroid gland and confidence of each assessment (low, moderate or high) were noted, and intra- and inter-observer agreement calculated using Fleiss' kappa method. Sensitivities and specificities of the non-experts were calculated using the expert reader as gold standard. RESULTS: Intra-observer agreement was 'good' to 'near perfect' for all readers. Inter-observer agreement was good between non-experts and the expert, with kappa values ≥ 0.74. Sensitivities between non-experts and the expert were high, > 81%, when assessing which side and 75% when assessing thyroid quadrant. All specificities were > 94%. Reader certainties were 'high' in > 80% of cases for the expert and > 70% and > 65%, respectively for the two non-experts. CONCLUSION: 11C-Choline PET/CT is not reader sensitive for the localisation of hyperfunctioning parathyroid glands and may therefore be safely implemented at sites that have a moderate number of cases. Access to a cyclotron laboratory is, however, a necessity for the production of 11C-Choline. The study was conducted in accordance with the Helsinki 2 declaration and The International Council for Harmonisation Guideline for Good Clinical Practice (ICH_GCP) clinical trial, approved by the Research Ethics Committee of the Capital Region of Denmark (Journal-nr.:H-18012490, date of approval: 18 June 2018) and the Danish Medicines Agency (EudraCT no. 2018-000726-63, date of approval: 6 June 2018). The GCP unit in Eastern Denmark has carried out regular monitoring of the trial according to GCP (ID: 2018-1050).

Vibration Perception Threshold and Heart Rate Variability as methods to assess chemotherapy-induced neuropathy in women with breast cancer - a pilot study.

PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) is a recognized adverse effect of standard (neo)adjuvant chemotherapy in breast cancer (BC) treatment. However, there is no consensus on a validated method for assessing CIPN. Heart rate variability (HRV) and vibration perception threshold (VPT) could be used as objective measures to describe CIPN. The aim of this pilot study was to investigate whether subjectively reported CIPN was associated with altered HRV and VPT in BC patients. METHODS: We performed a cross-sectional pilot study evaluating 30 BCE patients previously treated with chemotherapy, 26 BCE patients who did not receive chemotherapy, and 22 controls without breast cancer. Self-reported CIPN was registered for the BC patients. All participants were subjected to multi-frequency vibration analyses to determine VPT along with short ECG measurements to determine HRV measures. RESULTS: Self-reported CIPN was registered in 14 (46.6%) BC patients treated with chemotherapy. The VPT at 64 Hz (P = 0.022) and mean HR (P = 0.022) were significantly higher and the HRV measures SDNN (P = 0.023), RMSSD (P = 0.007), LF (P = 0.050) and HF (P = 0.045) were significantly lower in BC patients reporting CIPN compared to controls when adjusted for age. VPT at 64 Hz and 125 Hz were significantly higher in BC patients not reporting CIPN compared to controls when adjusted for age. CONCLUSION: We found elevated VPT and mean HR along with decreased HRV parameters in 14 BCE patients reporting CIPN. These findings support the need for further investigation into whether HRV and vibration analysis could contribute to an objective assessment of CIPN.

Denosumab vs. zoledronic acid treatment in post-menopausal breast cancer: a 2-year prospective observational study.

Adjuvant treatment for post-menopausal women with early breast cancer (BC) includes aromatase inhibitors (AI), known to decrease bone mineral density (BMD). In this study, we investigate whether denosumab is a valid second option for patients unable to receive standard adjuvant i.v. zoledronic acid (ZA). In total, 212 patients have been evaluated after they did not receive ZA. Of those 194 were included. After evaluation by an endocrinologist, all patients were offered ZA as their first choice and 15% accepted (N = 29). The remaining 85% were offered denosumab (N = 165). All patients were followed prospectively with blood tests up to 24 months. DXA scans were performed at baseline and 24 months. No difference was observed between the two treatment groups at baseline, with regard to anthropometry and standard biochemistry. Markers of bone turnover (p-PINP, p-CTX, p-bone-specific alkaline phosphatase and p-osteocalcin) all showed significant suppression compared to baseline and remained suppressed throughout the 2 years. BMD showed small and significant increases at the spine (0.024 g/cm2) and total hip (0.019 g/cm2) in the denosumab group but no change at the femoral neck(-0.011g/cm2). In the ZA group, we observed no significant change at the spine (0.015 g/cm2) and total hip (-0.001g/cm2) and a small significant decrease at the femoral neck (-0.037 g/cm2). However, when we compared BMD change between the treatment groups, we found no significant difference.Conclusions: Our data indicate that for BC patients in AI treatment who refused or were not able to receive ZA treatment, denosumab might be recommended as a second choice. Regarding markers of bone turnover and BMD denosumab is equal to ZA.Summary: Women with early breast cancer receiving anti-estrogen treatment are at risk of developing osteoporosis.We followed 194 women receiving zoledronic acid (ZA) or denosumab for up to 2 years.We find that with regard to bone protection, denosumab is a viable alternative to ZA and might be recommended as a second choice.

Infrared Thermography as a Method of Verification in Raynaud's Phenomenon.

Raynaud's phenomenon (RP) is characterized by the episodic whitening of the fingers upon exposure to cold. A recently described thermographic algorithm was proposed as a diagnostic replacement of the currently applied finger systolic pressure (FSP) test. The aim of the study was to evaluate the performance of the thermographic algorithm when applied in patients suspected of having RP. Forty-three patients were examined using thermographic imaging after local cooling of the hands in water of 10 °C for 1 min. The thermographic algorithm was applied to predict the probability of RP. The performance of the algorithm was evaluated with different cut-off levels. A new algorithm was proposed based on patients from the target population. The performance of the tested algorithm was noninferior to the FSP test, when a cut-off level of 0.05 was applied, yielding a sensitivity and specificity of 69% and 58%, respectively. The accuracy was 66%. The FSP test had a sensitivity and specificity of 77% and 37%, respectively, and the accuracy was 59%. The thermographic method proved useful for detecting RP and was able to replace the FSP test as a diagnostic test. The alternative algorithm revealed that other thermographic variables were more predictive of the target population, but this should be verified in future patients.

Heart rate variability and vibration perception threshold to assess chemotherapy-induced neuropathy in women with breast cancer - a systematic review.

BACKGROUND: It is well known that breast cancer (BC) patients often suffer from chemotherapy-induced peripheral neuropathy (CIPN). However, it is not always recognized that they have higher risk of falling, dizziness and other signs of dysfunctional autonomous nervous system. We performed a systematic review of the literature on vibration perception threshold (VPT) and heart rate variability (HRV) as methods to objectively assess (CIPN) in BC-patients. Could VPT and HRV describe coexisting sensory and autonomic nerve damage? MATERIALS AND METHODS: PubMed was searched in September 2019. The included studies had to address HRV and/or VPT in BC-patients who received chemotherapy. RESULTS: Seven studies assessed VPT and six studies assessed HRV in BC-patients. Studies showed lowered perception of vibrations after chemotherapy reflected in higher VPT and no changes in HRV after taxane-based chemotherapy. No studies evaluated VPT and HRV at the same time. CONCLUSION: The results were limited by short follow-up, small sample sizes, and different chemotherapy regimens which makes generalizability problematic. A standard assessment method of CIPN is still missing and further research is needed to evaluate if VPT and HRV could contribute to an objective assessment of CIPN. With higher survival rates for BC-patients autonomous and sensory nerve damage will be an increasing task. However, our literature review showed that no one have focused on the combination of autonomous and sensory affection measured by the simple methods VPT and HRV. Therefore, we encourage the development of international guidelines for the objective measure of nerve damage in BC-patients.

Effects of empagliflozin on estimated extracellular volume, estimated plasma volume, and measured glomerular filtration rate in patients with heart failure (Empire HF Renal): a prespecified substudy of a double-blind, randomised, placebo-controlled trial.

BACKGROUND: SGLT2 inhibitors are a promising treatment option in patients with heart failure and reduced ejection fraction. We aimed to investigate the effects of empagliflozin on estimated extracellular volume, estimated plasma volume, and measured glomerular filtration rate (GFR) in patients with heart failure and reduced ejection fraction. METHODS: Empire HF Renal was a prespecified substudy of the investigator-initiated, double-blind, randomised, placebo-controlled Empire HF trial. The study was done at Herlev and Gentofte University Hospital (Herlev, Denmark), with patients recruited from four Danish heart failure outpatient clinics. Patients with New York Heart Association class I-III symptoms, with a left ventricular ejection fraction of 40% or lower, and on guideline-directed heart failure therapy were randomly assigned (1:1) to receive either oral empagliflozin 10 mg or matched placebo once daily for 12 weeks. The allocation sequence was computer-generated. Patients and study investigators were masked to treatment allocation. The coprimary prespecified renal outcomes were the between-group difference in the changes in estimated extracellular volume, estimated plasma volume, and measured GFR from baseline to 12 weeks. All analyses were done in the intention-to-treat population (apart from safety analyses, which were done in patients who received at least one dose of study drug), with no interim analyses done during the trial. The Empire HF trial is registered with ClinicalTrials.gov, NCT03198585, and EudraCT, 2017-001341-27. FINDINGS: Between June 29, 2017, and July 15, 2019, we assessed 391 patients for eligibility, of whom 120 (31%) were randomly assigned to empagliflozin or placebo, including 105 (88%) without diabetes. In intention-to-treat analyses, 60 (100%) patients in the empagliflozin group and 59 (98%) patients in the placebo group were included for estimated extracellular volume and estimated plasma volume, and 59 (98%) patients in the empagliflozin group and 58 (97%) patients in the placebo group were included for measured GFR. Empagliflozin treatment resulted in reductions in estimated extracellular volume (adjusted mean difference -0·12 L, 95% CI -0·18 to -0·05; p=0·00056), estimated plasma volume (-7·3%, -10·3 to -4·3; p<0·0001), and measured GFR (-7·5 mL/min, -11·2 to -3·8; p=0·00010) compared with placebo. Five (8%) of 60 patients in the empagliflozin group and three (5%) of 60 patients in the placebo group had one or more serious adverse events. INTERPRETATION: In patients with heart failure and reduced ejection fraction, empagliflozin reduced estimated extracellular volume, estimated plasma volume, and measured GFR after 12 weeks. Fluid volume changes might be an important mechanism underlying the beneficial clinical effects of SGLT2 inhibitors. FUNDING: Research Council at Herlev and Gentofte University Hospital, Research and Innovation Foundation of the Department of Cardiology at Herlev and Gentofte University Hospital, Capital Region of Denmark, Danish Heart Foundation, and AP Møller Foundation for the Advancement of Medical Science.

11C-Choline PET/CT vs. 99mTc-MIBI/123Iodide Subtraction SPECT/CT for Preoperative Detection of Abnormal Parathyroid Glands in Primary Hyperparathyroidism: A Prospective, Single-Centre Clinical Trial in 60 Patients.

BACKGROUND: In patients with primary hyperparathyroidism (PHPT) locating hyperfunctioning glands (HPGs) is crucial when planning minimally invasive surgery. Dual-isotope subtraction scintigraphy with 99mTc-MIBI/123Iodide using SPECT/CT and planar pinhole imaging (Method A) has previously shown a sensitivity >93%. However, the method is costly and time consuming and entails a high radiation dose. 11C-Choline PET/CT (Method B) is an appealing candidate method unencumbered by these disadvantages. METHODS: Sixty patients with newly diagnosed PHPT participated and were scanned using both methods prior to parathyroidectomy. We investigated whether sensitivities of Method A and Method B are similar in a method-to-method comparison when using surgical findings as the true location. RESULTS: At the patient level, sensitivities were (A) 0.98 (95% CI: 0.90-1.00) and (B) 1.00 (95% CI: 0.93-1.00). At the gland level, sensitivities were (A) 0.88 (95% CI: 0.78-0.94) and (B) 0.87 (95% CI: 0.76-0.92). With a non-inferiority margin of ∆ = -0.1, we found a 1-sided p-value < 0.001. CONCLUSION: Our methods comparison study found that sensitivity of Method B was not inferior to Method A. We suggest that 11C-Choline PET/CT is a clinically relevant first-choice candidate for preoperative imaging of PHPT and that Method B can likely replace Method A in the near future.

Hypophosphatemic Hypovitaminosis D Induces Osteomalacia in the Adult Female Rat.

Osteomalacia is a bone-demineralizing disease of adulthood, often caused by hypovitaminosis D. Current animal models of the disease mimic osteomalacia as a consequence of gastric bypass or toxic exposure to metals, but a relevant model of diet-induced osteomalacia is lacking. For that purpose, 7-month-old female Sprague Dawley rats were randomly assigned into 2 weight-stratified groups and maintained for 4 months on synthetic diets containing negligible or normal levels of vitamin D. The dietary regimen resulted in vitamin D deficiency as measured by 25-hydroxyvitamin D serum levels; however, hypovitaminosis D per se did not affect biomarkers of calcium metabolism and bone turnover, nor did it result in increased osteoid. Thus, vitamin D depletion through the diet was found to be insufficient to induce an osteomalacia-like phenotype in the adult rat. After 4 months, the phosphate content of the vitamin D-depleted diet had decreased to 0.16% (calcium:phosphorus ratio of 5.85), resulting in an osteomalacic-like condition (trabecular osteoid surface/bone surface constituted 33%; CI, 26-40). The diet change also affected both metabolic and bone turnover biomarkers, including significantly suppressing serum fibroblast growth factor 23. Furthermore, decreased dietary phosphate in a vitamin D-depleted diet led to microarchitectural changes of trabecular and cortical bone, lower bone mass density, lower bone mass content and decreased bone strength, all indicating reduced bone quality. Taken together, our results show that osteomalacia can be induced in the adult female rat by depleting vitamin D and lowering phosphate content in the diet.

The relation between dopamine D2 receptor blockade and the brain reward system: a longitudinal study of first-episode schizophrenia patients.

BACKGROUND: Psychotic symptoms have been linked to salience abnormalities in the brain reward system, perhaps caused by a dysfunction of the dopamine neurotransmission in striatal regions. Blocking dopamine D2 receptors dampens psychotic symptoms and normalises reward disturbances, but a direct relationship between D2 receptor blockade, normalisation of reward processing and symptom improvement has not yet been demonstrated. The current study examined the association between blockade of D2 receptors in the caudate nucleus, alterations in reward processing and the psychopathology in a longitudinal study of antipsychotic-naïve first-episode schizophrenia patients. METHODS: Twenty-two antipsychotic-naïve first-episode schizophrenia patients (10 males, mean age 23.3) and 23 healthy controls (12 males, mean age 23.5) were examined with single-photon emission computed tomography using 123I-labelled iodobenzamide. Reward disturbances were measured with functional magnetic resonance imaging (fMRI) using a modified version of the monetary-incentive-delay task. Patients were assessed before and after 6 weeks of treatment with amisulpride. RESULTS: In line with previous results, patients had a lower fMRI response at baseline (0.2 ± 0.5 v. 0.7 ± 0.6; p = 0.008), but not at follow-up (0.5 ± 0.6 v. 0.6 ± 0.7), and a change in the fMRI signal correlated with improvement in Positive and Negative Syndrome Scale positive symptoms (ρ = -0.435, p = 0.049). In patients responding to treatment, a correlation between improvement in the fMRI signal and receptor occupancy was found (ρ = 0.588; p = 0.035). CONCLUSION: The results indicate that salience abnormalities play a role in the reward system in schizophrenia. In patients responding to a treatment-induced blockade of dopamine D2 receptors, the psychotic symptoms may be ameliorated by normalising salience abnormalities in the reward system.

Oxygen conserving mitochondrial adaptations in the skeletal muscles of breath hold divers.

BACKGROUND: The performance of elite breath hold divers (BHD) includes static breath hold for more than 11 minutes, swimming as far as 300 m, or going below 250 m in depth, all on a single breath of air. Diving mammals are adapted to sustain oxidative metabolism in hypoxic conditions through several metabolic adaptations, including improved capacity for oxygen transport and mitochondrial oxidative phosphorylation in skeletal muscle. It was hypothesized that similar adaptations characterized human BHD. Hence, the purpose of this study was to examine the capacity for oxidative metabolism in skeletal muscle of BHD compared to matched controls. METHODS: Biopsies were obtained from the lateral vastus of the femoral muscle from 8 Danish BHD and 8 non-diving controls (Judo athletes) matched for morphometry and whole body VO2max. High resolution respirometry was used to determine mitochondrial respiratory capacity and leak respiration with simultaneous measurement of mitochondrial H2O2 emission. Maximal citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HAD) activity were measured in muscle tissue homogenates. Western Blotting was used to determine protein contents of respiratory complex I-V subunits and myoglobin in muscle tissue lysates. RESULTS: Muscle biopsies of BHD revealed lower mitochondrial leak respiration and electron transfer system (ETS) capacity and higher H2O2 emission during leak respiration than controls, with no differences in enzyme activities (CS and HAD) or protein content of mitochondrial complex subunits myoglobin, myosin heavy chain isoforms, markers of glucose metabolism and antioxidant enzymes. CONCLUSION: We demonstrated for the first time in humans, that the skeletal muscles of BHD are characterized by lower mitochondrial oxygen consumption both during low leak and high (ETS) respiration than matched controls. This supports previous observations of diving mammals demonstrating a lower aerobic mitochondrial capacity of the skeletal muscles as an oxygen conserving adaptation during prolonged dives.