Residual inflammatory risk after contemporary lipid lowering therapy

BACKGROUND

Recently, there has been an increasing interest in targeting inflammation to reduce major adverse cardiovascular events (MACE) in patients with cardiovascular risk. Statins, PCSK9 inhibitors, and ezetimibe have been shown to reduce MACE owing to reduction in low-density lipoproteins cholesterol (LDL-c). Herein, we investigate whether the intensity of these agents is associated with (i) discernible reduction in inflammation measured by the levels of high-sensitivity C-reactive protein (hsCRP); (ii) reduction in MACE; (iii) if there is an association between the baseline hsCRP and MACE.

METHODS AND RESULTS

Electronic databases were searched for randomized controlled trials (RCTs) that compared statins, ezetimibe, PCSK9 inhibitors with placebos/active controls and reported MACEs and hsCRP (mg/L). Studies were stratified based on baseline hsCRP (<2, 2-3, >3) with subgroup analysis conducted across each stratum. Fourteen RCTs including 133 109 patients randomized into more intensive therapy (MIT) and less intensive therapy were selected. Meta-analysis did not demonstrate any significant differences between use of MIT and hsCRP levels (mean difference, -0.02; CI, -0.06, 0.02; P = 0.31). The MIT significantly reduced the risk of MACE (RR, 0.82; CI, 0.75, 0.91; P < 0.001). The relative risk and absolute risk remained consistent across the strata. However, there was a 0.5% statistically significant absolute risk reduction in all-cause mortality in patients with higher hsCRP (RD, -0.005; CI, -0.009, -0.001; P = 0.01).

CONCLUSION

Overall, LDL-c lowering therapies reduce relative risk of MACEs particularly in patients with higher baseline hsCRP. However, there appears to be a residual inflammatory risk despite the use of contemporary lipid lowering agents.

Effects of Influenza Vaccine on Mortality and Cardiovascular Outcomes in Patients With Cardiovascular Disease: A Systematic Review and Meta-Analysis

Background

Influenza infection causes considerable morbidity and mortality in patients with cardiovascular disease. We assessed the effects of the influenza vaccine on mortality and cardiovascular outcomes in patients with cardiovascular disease.

Methods and Results

We searched PubMed, Embase, and the Cochrane Library through January 2020 for randomized controlled trials and observational studies assessing the effects of influenza vaccine on mortality and cardiovascular outcomes in patients with cardiovascular disease. Estimates were reported as random effects risk ratios (RRs) with 95% CIs. Analyses were stratified by study design into randomized controlled trials and observational studies. A total of 16 studies (n=237 058), including 4 randomized controlled trials (n=1667) and 12 observational studies (n=235 391), were identified. Participants' mean age was 69.2±7.01 years, 36.6% were women, 65.1% had hypertension, 31.1% had diabetes mellitus, and 23.4% were smokers. At a median follow‐up duration of 19.5 months, influenza vaccine was associated with a lower risk of all‐cause mortality (RR, 0.75; 95% CI, 0.60–0.93 [P=0.01]), cardiovascular mortality (RR, 0.82; 95% CI, 0.80–0.84 [P<0.001]), and major adverse cardiovascular events (RR, 0.87; 95% CI, 0.80–0.94 [P<0.001]) compared with control. The use of the influenza vaccine was not associated with a statistically significant reduction of myocardial infarction (RR, 0.73; 95% CI, 0.49–1.09 [P=0.12]) compared with control.

Conclusions

Data from both randomized controlled trials and observational studies support the use of the influenza vaccine in adults with cardiovascular disease to reduce mortality and cardiovascular events, as currently supported by clinical guidelines. Clinicians and health systems should continue to promote the influenza vaccine as part of comprehensive secondary prevention.

Efficacy of photobiomodulation in the management of tinnitus: A systematic review of randomized control trials

There is a controversy in regards to the efficacy of photobiomodulation (PBM) in the management of tinnitus. The aim was to systematically review randomized controlled trials (RCTs) that assessed the efficacy of PBM (low-level laser therapy) in the management of tinnitus. The focused question was "Is PBM effective in the management of tinnitus?". Indexed databases were searched up to and including June 2020 using different combinations of the following key words: (a) laser; (b) diode; (c) low-level laser therapy; (d) photobiomodulation; (e) tinnitus; (f) medium-level laser; (g) photo-biomodulation; and (h) low-power laser; and RCTs performed on humans were included. Letters to the editor; case reports/series; commentaries; experimental studies and historic reviews were excluded. The risk of bias was assessed using the modified cochrane collaboration tool. The format of the current systematic review was personalized to summarize the appropriate information. Ten RCTs (2 single-blinded and 8 double-blinded) were included. One study reported 30% and 100% resolution of tinnitus using diode and Neodymium-doped Yttrium Aluminum Garnet lasers; respectively. One study reported that PBM was effective in relieving tinnitus for up to 3 months. Eight studies reported that PBM was ineffective in the management of chronic tinnitus. The risk of bias was high; medium and low in 4; 5 and 1 studies; respectively. The effectiveness of PBM in the management of tinnitus remains debatable. Further power-adjusted and well-designed RCTs with long-term follow-up are needed.

Review of Bone Modifying Agents in Metastatic Breast Cancer

Bone is the most common site for distant metastases in breast cancer and can cause significant morbidity and mortality. Bone modifying agents (BMAs) that include bisphosphonates (BPAs) and denosumab help in decreasing and delaying skeletal-related events (SREs) associated with metastatic breast cancer. BPAs approved for use by the Food and Drug Administration (FDA) in bone metastases (BM) in the United States are pamidronate and zolendronic acid, while clodronate and ibandronate are licensed for use in other countries. Current American Society of Clinical Oncology (ASCO) guidelines recommend denosumab 120 mg subcutaneously every four weeks, or zolendronic acid 4 mg every four weeks or every 12 weeks, or intravenous pamidronate 90 mg every four weeks. Current guidelines do not recommend one BMA over another, however, zolendronic acid and denosumab were the most commonly used BMAs in population-based studies. Side effects of BMAs include acute phase reactions, hypocalcemia, nephrotoxicity, osteonecrosis of jaw, etc. While other side effects are common with both BPAs and denosumab, the latter has less nephrotoxic potential and is preferred for use in patients with renal failure. Current ASCO guidelines recommend continuing BMAs indefinitely, however, in clinical practice, this decision needs to be individualized, especially since there is no data on the impact of long-term use of BMAs. Further studies would need to be developed to develop an algorithm of SRE risk assessment and to determine which patients would benefit from BMAs.

Representation of women, older patients, ethnic, and racial minorities in trials of atrial fibrillation

BACKGROUND

Representation trends of women, older adults, and ethnic/racial minorities in randomized controlled trials (RCTs) of atrial fibrillation (AF) are uncertain.

METHODS

We systematically reviewed 134 AF related RCTs (phase II and III) encompassing 149,162 participants using Medline and ClinicalTrials.gov through April 2019 to determine representation trends of women, older patients (≥75 years), and ethnic/racial minorities. Weighted data on the prevalence of AF from epidemiological studies were used to compare the representation of the studied groups of interest in AF RCTs to their expected burden of the disease.

RESULTS

Only 18.7% of the RCTs reported proportion of older patients, and 12.7% RCTs reported ethnic/racial minorities. The proportions of women in RCTs versus general population were 35.2% and 35.1%, of Hispanics were 11.9% and 5.2%, of Blacks were 1.2% and 5.7%, of American Indian/Alaskans were 0.2% and 0.2%, of Asians were 14.2% and 2.4%, of native Hawaiian/Pacific Islanders were 0.05% and 0.1% and of non-Whites were 19.5% and 22.5%, respectively. The weighted mean age (SD) across the trials was 65.3 (3.2) years which was less than the corresponding weighted mean age of 71.1 (4.5) years in the comparative epidemiological data.

CONCLUSION

The reporting of older patients and ethnic/racial minorities was poor in RCTs of AF. The representation of women and American Indian/Alaskan natives matched their expected population share of disease burden. Hispanics and Asians were over-represented and Blacks, native Hawaiian/Pacific Islanders and non-Whites were under-represented in RCTs of AF.

Bilateral Primary Marginal Zone Lymphoma of the Breast - A Rare Breast Malignancy

Extranodal marginal zone lymphoma (EMZL) presents only rarely within the breast, although the incidence of breast EMZL has increased in the past decade for unclear reasons. Due to its rarity, the etiology, course, and treatment response of this cancer are less studied. Case Report: We present the case of a 64-year-old female who had bilateral diffuse irregularity in a trabecular pattern on screening mammogram. Random ultrasound-guided breast biopsy of the right breast demonstrated an extra-nodal marginal zone B-cell lymphoma. She also had approximately 25% marrow involvement by mucosa-associated lymphoid tissue-type marginal zone lymphoma and splenomegaly. Clinically she remained asymptomatic during a 1-year follow-up. Although she presented with advanced-stage disease involving both breasts, spleen and bone marrow, given her lack of associated symptoms, she was observed with active surveillance. Conclusion: Asymptomatic cases of breast EMZL can be managed with close observation as exemplified by our case.

Fecal Microbiota Transplantation for Recurrent Clostridium difficile Infection in Patients With Multiple Comorbidities: Long-Term Safety and Efficacy Results From a Tertiary Care Community Hospital

Background

Cure rates of Clostridium difficile infection (CDI) with fecal microbiota transplant (FMT) have been promising. However, there is debate regarding success of FMT in patients with comorbidities.

Methods

Electronic chart review was done to collect data on patients who underwent FMT from January 2015 to August 2017. Charts were analyzed in November 2018 with a median follow-up of 25.4 months (interquartile range 20 - 31 months).

Results

Twenty patients underwent FMT. The primary success rate at our institution was 90% and overall success rate was 100%. Six patients (43%) had FMT failure (two early and four late).

Conclusions

This case series is a description of our center’s initial experience with FMT for treatment of recurrent CDI. Our high success rate reiterates the efficacy and safety of FMT in this population including patients with comorbidities.

Evaluating cortico-cancellous ratio using virtual implant planning and its relation with immediate and long-term stability of a dental implant- A CBCT-assisted prospective observational clinical study

BACKGROUND

Primary and long-term implant stabilities are crucial in predicting the success of dental implants. We aimed to evaluate corticocancellous ratio (CCR) around virtual implant using cone beam computed tomography (CT) and assess its relationship with immediate and long-term stability of the implants placed.

MATERIALS AND METHODS

A total of 135 image records of posterior mandibular implant sites planned for dental implant were included in our study. CCR was calculated using CT images and implants were placed after stent preparation. Implant stability was calculated immediately, 4 months later, and 2 years later.

RESULTS

Pearson's correlation test showed a significant correlation (P and lt; 0.001) between CCR and implant stability. ANOVA and post-hoc Tukey tests showed a significant difference in implant stability between groups with different CCRs at all follow-up timepoints. No significant difference was found between mean implant stability quotient values for low CCR at 2-year follow-up and high CCR immediately after implant placement.

CONCLUSIONS

Implant stability is improved with greater CCR. Cortical bone seems to be crucial factor for immediate and long-term stability of a dental implant. Virtual planning using CT can assess implant stability. Further histological studies are required to confirm the relation between CCR and implant stability. The escalating demand of the implant treatment in the dental practice necessitates measuring the several predictors of procedure success. This study introduces a novel predictor (CCR) around virtual implant for detecting the immediate and long-term stability of a dental implant.

MON-343 Nocardia Farcinia Adrenal Abscess Mimicking Adrenal Adenoma

Background: Infection by Nocardia in immunocompetent individuals is uncommon. Isolated adrenal involvement by Nocardia is rare. We report a case of unilateral Nocardia adrenal abscess that presented as lesion mimicking adrenal adenoma which resulted in dissemination in an immunocompetent host. Case Presentation: A 67 years old male with past medical history of coronary artery disease presented to his physician’s office with 5/10 pain in the left flank area for two weeks that radiated into the left upper quadrant. He had weight loss more than 10 pounds in one month, anorexia and night sweats. On examination, he was hemodynamically stable and there was no abdominal tenderness. Routine blood work and a computed tomography [CT] scan of abdomen was obtained that showed a heterogeneously enhancing 8.1 cm x 4 cm x 5 cm partially necrotic left adrenal mass [Figure 1]. Lab work revealed that serum aldosterone, serum renin, plasma metanephrine and urine free cortisol were in normal range. In a few days, patient presented with acute episode of hypotension to the Emergency department. A CT scan of abdomen was that revealed he had large retroperitoneal fluid collection. He received intravenous fluid resuscitation and was started on empiric treatment with Vancomycin and Piperacillin-tazobactam for concern of sepsis. He underwent surgical exploration, incision and drainage of left retroperitoneal abscess collection with removal of two liters of purulent fluid [Figure 2]. Initial gram stain had shown filamentous, acid fast bacteria. He was started on treatment empirically with Amikacin, Trimethoprim–sulfamethoxazole [TMP–SMX] and Imipenem- Cilastatin. The patient was found to have disseminated nocardiosis with positive blood cultures and abdominal abscess growing Nocardia farcinica. Antibiotics were tapered to Imipenem- Cilastatin, Amikacin and Moxifloxacin to complete six weeks of antibiotic therapy. CT scans of chest and head were obtained which did not reveal any signs of abscess. Patient recovered well with repeat imaging studies showing resolution of the abscess. Conclusion: Nocardia involvement of adrenal gland is a rare phenomenon, it can present as solitary adrenal lesion or with dissemination. This can mimic adrenal adenoma on CT scan. On review of existing medical research, less than ten cases of isolated Nocardia adrenal abscess leading to dissemination has been described so far. Isolated involvement of the adrenal gland poses diagnostic challenge because of non-localizing symptoms and late presentation with dissemination. Figure 1 Partially necrotic left adrenal massFigure 2 Retroperitoneal abscess

Aspirin for primary prevention of cardiovascular outcomes in diabetes mellitus: An updated systematic review and meta-analysis

BACKGROUND

The safety and efficacy of aspirin for the primary prevention of cardiovascular disease in patients with diabetes mellitus remains controversial.

DESIGN

A meta-analysis to investigate the effects of aspirin for the prevention of cardiovascular disease in diabetes mellitus.

METHODS

Ten randomized controlled trials were selected using MEDLINE, EMBASE and CENTRAL databases until 27 September 2018. Risk ratios (RRs) with 95% confidence intervals (CIs) and risk differences (RDs) reported as incident events per 1000 person-years were calculated.

RESULTS

In 33,679 patients, aspirin did not significantly reduce the risk of major adverse cardiovascular outcomes (RR 0.93, 95% CI 0.87-1.00, P = 0.06; RD -0.68 incident cases per 1000 person-years (95% CI -1.54, 0.17)), cardiovascular mortality (RR 0.95, 95% CI 0.83-1.09, P = 0.49; RD 0.11 incident cases per 1000 person-years (95% CI -0.80, 1.02)), myocardial infarction (RR 0.91, 95% CI 0.75-1.11, P = 0.36; RD -0.66 incident cases per 1000 person-years (95% CI -2.07, 0.75)), or stroke (RR 0.91, 95% C, 0.76-1.10, P = 0.33; RD -0.55 incident cases per 1000 person-years (95% CI -1.57, 0.47)). There was a significantly higher risk of total bleeding associated with aspirin (RR 1.29, 95% CI 1.07-1.55, P = 0.01; RD 1.49 incident cases per 1000 person-years (95% CI 0.36, 2.61)).

CONCLUSION

The use of aspirin for primary prevention of cardiovascular disease in patients with diabetes mellitus increases the risk of total bleeding without reducing the risk of major adverse cardiovascular outcomes.

The roles of homologous recombination and the immune system in the genomic evolution of cancer

A variety of factors, whether extracellular (mutagens/carcinogens and viruses in the environment, chronic inflammation and radiation associated with the environment and/or electronic devices/machines) and/or intracellular (oxidative metabolites of food, oxidative stress due to inflammation, acid production, replication stress, DNA replication/repair errors, and certain hormones, cytokines, growth factors), pose a constant threat to the genomic integrity of a living cell. However, in the normal cellular environment multiple biological pathways including DNA repair, cell cycle, apoptosis and the immune system work in a precise, regulated (tightly controlled), timely and concerted manner to ensure genomic integrity, stability and proper functioning of a cell. If damage to DNA takes place, it is efficiently and accurately repaired by the DNA repair systems. Homologous recombination (HR) which utilizes either a homologous chromosome (in G1 phase) or a sister chromatid (in G2) as a template to repair the damage, is known to be the most precise repair system. HR in G2 which utilizes a sister chromatid as a template is also called an error free repair system. If DNA damage in a cell is so extensive that it overwhelms the repair system/s, the cell is eliminated by apoptosis. Thus, multiple pathways ensure that genome of a cell is intact and stable. However, constant exposure to DNA damage and/or dysregulation of DNA repair mechanism/s poses a risk of mutation and cancer. Oncogenesis, which seems to be a multistep process, is associated with acquisition of a number of genomic changes that enable a normal cell to progress from benign to malignant transformation. Transformed/cancer cells are recognized and killed by the immune system. However, the ongoing acquisition of new genomic changes enables cancer cells to survive/escape immune attack, evolve into a more aggressive phenotype, and eventually develop resistance to therapy. Although DNA repair (especially the HR) and the immune system play unique roles in preserving genomic integrity of a cell, they can also contribute to DNA damage, genomic instability and oncogenesis. The purpose of this article is to highlight the roles of DNA repair (especially HR) and the immune system in genomic evolution, with special focus on gastrointestinal cancer.

Efficacy and safety of mechanical versus manual compression in cardiac arrest - A Bayesian network meta-analysis

AIM

To compare relative efficacy and safety of mechanical compression devices (AutoPulse and LUCAS) with manual compression in patients with cardiac arrest undergoing cardiopulmonary resuscitation (CPR).

METHODS

For this Bayesian network meta-analysis, seven randomized controlled trials (RCTs) were selected using PubMed/Medline, EMBASE, and CENTRAL (Inception- 31 October 2017). For all the outcomes, median estimate of odds ratio (OR) from the posterior distribution with corresponding 95% credible interval (Cr I) was calculated. Markov chain Monte Carlo (MCMC) modeling was used to estimate the relative ranking probability of each intervention based on surface under the cumulative ranking curve (SUCRA).

RESULTS

In analysis of 12, 908 patients with cardiac arrest [AutoPulse (2, 608 patients); LUCAS (3, 308 patients) and manual compression (6, 992 patients)], manual compression improved survival at 30 days or hospital discharge (OR, 1.40, 95% Cr I, 1.09-1.94), and neurological recovery (OR, 1.51, 95% Cr I, 1.06-2.39) compared to AutoPulse. There were no differences between LUCAS and AutoPulse with regards to survival to hospital admission, neurological recovery or return of spontaneous circulation (ROSC). Manual compression reduced the risk of pneumothorax (OR, 0.56, 95% Cr I, 0.33-0.97); while, both manual compression (OR, 0.15, 95% Cr I, 0.01-0.73) and LUCAS (OR, 0.07, 95% Cr I, 0.00-0.43) reduced the risk of hematoma formation compared to AutoPulse. Probability analysis ranked manual compression as the most effective treatment for improving survival at 30 days or hospital discharge (SUCRA, 84%).

CONCLUSIONS

Manual compression is more effective than AutoPulse and comparable to LUCAS in improving survival at 30 days or hospital discharge and neurological recovery. Manual compression had lesser risk of pneumothorax or hematoma formation compared to AutoPulse.

A Bayesian network meta-analysis of PCSK9 inhibitors, statins and ezetimibe with or without statins for cardiovascular outcomes

Background

The comparative effects of statins, ezetimibe with or without statins and proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors remain unassessed.

Design

Bayesian network meta-analysis was conducted to compare treatment groups.

Methods

Thirty-nine randomized controlled trials were selected using MEDLINE, EMBASE, and CENTRAL (inception – September 2017).

Results

In network meta-analysis of 189,116 patients, PCSK9 inhibitors were ranked as the best treatment for prevention of major adverse cardiovascular events (Surface Under Cumulative Ranking Curve (SUCRA), 85%), myocardial infarction (SUCRA, 84%) and stroke (SUCRA, 80%). PCSK9 inhibitors reduced the risk of major adverse cardiovascular events compared with ezetimibe + statin (odds ratio (OR): 0.72; 95% credible interval (CrI), 0.55–0.95; Grading of Recommendation Assessment, Development and Evaluation (GRADE) criteria: moderate), statin (OR: 0.78; 95% CrI: 0.62–0.97; GRADE: moderate) and placebo (OR: 0.63; 95% CrI: 0.49–0.79; GRADE: high). The PCSK9 inhibitors were consistently superior to groups for major adverse cardiovascular event reduction in secondary prevention trials (SUCRA, 95%). Statins had the highest probability of having lowest rates of all-cause mortality (SUCRA, 82%) and cardiovascular mortality (SUCRA, 84%). Compared with placebo, statins reduced the risk of all-cause mortality (OR: 0.88; 95% CrI: 0.83–0.94; GRADE: moderate) and cardiovascular mortality (OR: 0.84; 95% CrI: 0.77–0.90; GRADE: high). For cardiovascular mortality, PCSK9 inhibitors were ranked as the second best treatment (SUCRA, 78%) followed by ezetimibe + statin (SUCRA, 50%).

Conclusion

PCSK9 inhibitors were ranked as the most effective treatment for reducing major adverse cardiovascular events, myocardial infarction and stroke, without having major safety concerns. Statins were ranked as the most effective therapy for reducing mortality.

Implantable cardioverter defibrillator in nonischemic cardiomyopathy: A systematic review and meta-analysis

The evidence to support implantable cardioverter defibrillator (ICD) in subjects with nonischemic cardiomyopathy (NICM) for primary prevention of sudden cardiac death (SCD) is not robust. This meta-analysis intends to assess the impact of routine ICD implantation for primary prevention of mortality due to SCD in NICM based on all the published randomized clinical trials (RCTs). Six RCTs were selected using PubMed/Medline, EMBASE, and CENTRAL from inception to December 2016. Outcomes were calculated as random-effects relative risk (RR) and risk difference (RD) with 95% confidence interval (CI). Patients were randomized to ICD arm and control arm (usual care, medical treatment, and anti-arrhythmic drugs). ICD significantly reduced all-cause mortality in NICM patients (RR, 0.74, 95% CI, 0.56-0.97, P = .03, I2 = 40). Mortality benefit was achieved due to a significant reduction in sudden cardiac death (SCD) (RR, 0.47, 95% CI, 0.30-0.73, P < .001, I2 = 0). There were no statistical differences between two groups with regard to risk of noncardiac mortality, non-SCD, cardiac arrest, cardiac transplant, sustained ventricular tachycardia (VT), and VT requiring medical treatment. Our results support efficacy of ICDs at reducing all-cause mortality due to a reduction in SCD.

Meta-Analysis of the Safety and Efficacy of the Oral Anticoagulant Agents (Apixaban, Rivaroxaban, Dabigatran) in Patients With Acute Coronary Syndrome

The significance of adding new oral anticoagulants (NOACs) to antiplatelet therapy in patients with acute coronary syndrome (ACS) is unclear. We conducted a meta-analysis to assess the safety and efficacy of adding NOACs (apixaban, rivaroxaban, and dabigatran) to single antiplatelet agent (SAP) or dual antiplatelet therapy (DAPT) in patients with ACS. Seven randomized controlled trials were selected using PubMed or MEDLINE, Scopus, and Cochrane library (inception to August 2017). The summary measure was random effects hazard ratio (HR) with 95% confidence interval (CI). The primary safety outcome was clinically significant bleeding. The secondary efficacy outcome was major adverse cardiovascular events (MACE; composite of myocardial infarction, stroke, and all-cause mortality). In 31,574 patients, addition of NOAC to SAP did not increase the risk of clinically significant bleeding (HR 0.82, 95% CI 0.56 to 1.20, p = 0.31); however, the risk of clinically significant bleeding was significantly increased with NOAC plus DAPT (HR 2.24, 95% CI 1.75 to 2.87, p < 0.001). NOACs had no statistically beneficial effect on MACE when used with SAP (HR 0.82, 95% CI 0.66 to 1.04, p = 0.10); however, a modest reduction in MACE was observed when NOACs were combined with DAPT (HR 0.86, 95% CI 0.78 to 0.93, p < 0.001). In conclusion, in patients with ACS, the addition of NOAC to DAPT resulted in increased risk of clinically significant bleeding, whereas only a modest reduction in MACE was achieved. The addition of NOACs to SAP did not result in significant reduction of MACE or increase in clinically significant bleeding.

Atypical presentation of central pontine myelinolysis in hyperglycemia

Central pontine myelinolysis (CPM) usually occurs with rapid correction of severe chronic hyponatremia. Despite the pronounced fluctuations in serum osmolality, CPM is rarely seen in diabetics. This is a case report of CPM associated with hyperglycemia. A 45-year-old non-smoking and non-alcoholic African American male with past medical history of type 2 diabetes, hypertension, stage V chronic kidney disease and hypothyroidism presented with a two-week history of intermittent episodes of gait imbalance, slurred speech and inappropriate laughter. Physical examination including complete neurological assessment and fundoscopic examination were unremarkable. Laboratory evaluation was significant for serum sodium: 140 mmol/L, potassium: 3.9 mmol/L, serum glucose: 178 mg/dL and serum osmolality: 317 mosmol/kg. His ambulatory blood sugars fluctuated between 100 and 600 mg/dL in the six weeks prior to presentation, without any significant or rapid changes in his corrected serum sodium or other electrolyte levels. MRI brain demonstrated a symmetric lesion in the central pons with increased signal intensity on T2- and diffusion-weighted images. After neurological consultation and MRI confirmation, the patient was diagnosed with CPM secondary to hyperosmolar hyperglycemia. Eight-week follow-up with neurology was notable for near-complete resolution of symptoms. This case report highlights the importance of adequate blood glucose control in diabetics. Physicians should be aware of complications like CPM, which can present atypically in diabetics and is only diagnosed in the presence of a high index of clinical suspicion.

LEARNING POINTS

Despite the pronounced fluctuations in serum osmolality, central pontine myelinolysis (CPM) is rarely seen in diabetics. This case report of CPM associated with hyperglycemia highlights the importance of adequate blood glucose control in diabetics.Physicians should be aware of complications like CPM in diabetics.CPM can present atypically in diabetics and is only diagnosed in the presence of a high index of clinical suspicion.

Male breast carcinoma in United States: Survival rate and determinants of prognosis

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Background: Male breast cancer (MBC) is rare and accounts for less than 1% of all cancers in men. It causes significant morbidity and mortality due to late diagnosis. The primary objective of our study is to update information about the receptor status, pathology, survival rates, and prognostic factors for MBC. Our secondary objective is to determine racial differences in survival of MBC and compare tumor characteristics with female breast cancer (FBC) patients.

Methods: We analyzed a retrospective cohort of breast cancer patients included in National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) from 1990 to 2007. Differences between patient and disease characteristics at the time of diagnosis among MBC and FBC patients were compared using chi-square test. Overall survival was estimated using Kaplan-Meier method. Cox proportional hazards regression model was used to determine the independent variables that affect survival.

Results: We included 2,475 men and 393,259 women with breast cancer in our analysis. Median age at diagnosis was higher in men compared to women (67 vs 61years). Men had more frequent lymph node involvement (32% vs. 22%), ER positivity (66% vs. 57%) and PR positivity (57% vs. 49%) breast cancer than women (P<0.001). Overall median survival in MBC was 9 years, 5-year survival was 63% and 10-year survival was 43%. Increased age, larger tumor size, higher grade, lymph node involvement, ER and PR negative status were significantly associated with decreased survival in univariate analysis (P <0.05). In multivariate analysis, age > 65 years at the time of diagnosis, larger tumor size, positive lymph node status, ER negative status and poorly differentiated grade were associated with decreased survival (P <0.02). However PR status was not a significant predictor of survival. The median survival in African American males was lower as compared to Caucasians (7.08 vs. 9.2 yrs.) (P=0.02).

Conclusions: Male breast cancer differs from female breast cancer in important biological characteristics with a higher age at diagnosis and frequent lymph node involvement. Age greater than 65 years, tumor size, grade, lymph node involvement and ER status of the tumor are independent predictors of survival in MBC.

Exploration of the conformational space of oxytocin and arginine-vasopressin using the electrostatically driven Monte Carlo and molecular dynamics methods

Conformational analysis of the neurohypophyseal hormones oxytocin (OT) and arginine-vasopressin (AVP) has been carried out using two different computational approaches and three force fields, namely by the Electrostatically Driven Monte Carlo (EDMC) method, with the Empirical Conformational Energy Program for Peptides (ECEPP/3) force field or with the ECEPP/3 force field plus a hydration-shell model, and by simulated-annealing molecular dynamics with the Consistent Valence Force Field (CVFF). The low-energy conformations obtained for both hormones were classified using the minimal-tree clustering algorithm and characterized according to the locations of beta-turns in the cyclic moieties. Calculations with the CVFF force field located conformations with a beta-turn at residues 3 and 4 as the lowest energy ones both for OT and for AVP. In the ECEPP/3 force field the lowest energy conformation of OT contained a beta-turn at residues 2 and 3, conformations with this location of the turn being higher in energy for AVP. The latter difference can be attributed to the difference in the size of the side chain in position 3 of the sequences: the bulkier phenylalanine residue of AVP in combination with the bulky Tyr2 residue hinders the formation of a turn at residues 2 and 3. Conformations of OT and AVP with a turn at residues 3,4 were in the best agreement with the x-ray structures of deaminooxytocin and pressinoic acid (the cyclic moiety of vasopressin), respectively, and with the nmr-derived distance constraints. Generally, the low-energy conformations obtained with the hydration-shell model were in a better agreement with the experimental data than the conformations calculated in vacuo. It was found, however, that the obtained low-energy conformations do not satisfy all of the nmr-derived distance constraints and the nuclear Overhauser effect pattern observed in nmr studies can be fully explained only by assuming a dynamic equilibrium between conformations with beta-turns at residues 2,3, 3,4, and 4,5. The low-energy structures of OT with a beta-turn at residues 2,3 have the disulfide ring conformations close to the model proposed recently for a potent bicyclic antagonist of OT [M. D. Shenderovich et al. (1994) Polish Journal of Chemistry, Vol. 25, pp. 921-927], although the native hormone differs from the bicyclic analogue by the conformation of the C-terminal tripeptide. This finding confirms the hypothesis of different receptor-bound conformations of agonists and antagonists of OT.

Identification of a Drosophila G protein alpha subunit (dGq alpha-3) expressed in chemosensory cells and central neurons

We have identified another Drosophila GTP-binding protein (G protein) alpha subunit, dGq alpha-3. Transcripts encoding dGq alpha-3 are derived from alternative splicing of the dGq alpha locus previously shown to encode two visual-system-specific transcripts [Lee, Y.-J., Dobbs, M.B., Verardi, M.L. & Hyde, D.R. (1990) Neuron 5, 889-898]. Immunolocalization studies using dGq alpha-3 isoform-specific antibodies and LacZ fusion genes show that dGq alpha-3 is expressed in chemosensory cells of the olfactory and taste structures, including a subset of olfactory and gustatory neurons, and in cells of the central nervous system, including neurons in the lamina ganglionaris. These data are consistent with a variety of roles for dGq alpha-3, including mediating a subset of olfactory and gustatory responses in Drosophila, and supports the idea that some chemosensory responses use G protein-coupled receptors and the second messenger inositol 1,4,5-trisphosphate.

Solution structure of the pleckstrin homology domain of Drosophila beta-spectrin

BACKGROUND

The pleckstrin homology (PH) domain, which is approximately 100 amino acids long, has been found in about 70 proteins involved in signal transduction and cytoskeletal function, a frequency comparable to SH2 (src homology 2) and SH3 domains. PH domains have been shown to bind the beta gamma-subunits of G-proteins and phosphatidylinositol 4,5-bisphosphate (PIP2). It is conceivable that the PH domain of beta-spectrin plays a part in the association of spectrin with the plasma membrane of cells.

RESULTS

We have solved the solution structure of the 122-residue PH domain of Drosophila beta-spectrin. The overall fold consists of two antiparallel beta-sheets packing against each other at an angle of approximately 60 degrees to form a beta-sandwich, a two-turn alpha-helix unique to spectrin PH domains, and a four-turn C-terminal alpha-helix. One of the major insertions in beta-spectrin PH domains forms a long, basic surface loop and appears to undergo slow conformational exchange in solution. This loop shows big spectral changes upon addition of D-myo-inositol 1,4,5-trisphosphate (IP3).

CONCLUSIONS

We propose that the groove at the outer surface of the second beta-sheet is an important site of association with other proteins. This site and the possible lipid-binding site can serve to localize the spectrin network under the plasma membrane. More generally, it has to be considered that the common fold observed for the PH domain structures solved so far does not necessarily mean that all PH domains have similar functions. In fact, the residues constituting potential binding sites for ligands or other proteins are only slightly conserved between different PH domains.

Structural characterization of a three-disulfide intermediate of ribonuclease A involved in both the folding and unfolding pathways

Earlier studies of the unfolding pathway of native bovine pancreatic ribonuclease A (using dithiothreitol as the reducing agent) revealed that the three-disulfide species lacking the disulfide bond between cysteine 65 and cysteine 72 is the most highly populated intermediate [Rothwarf & Scheraga (1991) J. Am. Chem. Soc. 113, 6293-6294]. This unfolding intermediate is referred to as des-[65-72]-RNase A. In order to determine the role of des-[65-72]-RNase A, i.e. of the 65-72 disulfide bond, in the structural folding/unfolding processes of RNase A, the stability and structure of this unfolding intermediate were determined by examining its thermal transition curve and by using two- and three-dimensional homonuclear 1H NMR spectroscopy. The midpoint of the thermal transition of des-[65-72]-RNase A was found to be 17.8 degrees C lower than that of native RNase A. A set of conformations that are consistent with the NMR-derived constraints was obtained by minimizing, first, a variable-target function and, then, the conformational energy. These conformations exhibit a well-defined structure that is very similar to that of native ribonuclease A in regions where the native protein has a regular backbone structure such as a beta-sheet or a helix. Some of the loop regions of the several computed structures exhibit large deviations from each other as well as from native ribonuclease A. However, these results indicate that des-[65-72]-RNase A has a close structural similarity to RNase A in all regions with the only major differences occurring in a loop region comprising residues 60-72. This led to the conclusion that, in reduction pathways that include des-[65-72]-RNase A (at 25 degrees C, pH 8.0), the rate-determining step corresponds to a partial unfolding event in one region of the protein and not to a global conformational unfolding process. The results further suggest that, in the regeneration pathways involving des-[65-72]-RNase A, the loop region from 60 to 72 is the last to fold.

Amide H/D exchange in the thermal transition of bovine pancreatic ribonuclease A

The H/D exchange behavior of RNase A at pH 2.5 at a number of temperatures spanning the thermal transition region has been examined by NMR spectroscopy. The amide proton of V116 has a slow rate of H/D exchange even at temperatures above the midpoint of the thermal transition. The H/D exchange behavior of the peptide corresponding to residues 105-124 of RNase A and the peptide corresponding to residues 115-117 is compared with that of RNase A, showing that folding/unfolding cannot be described by a two-state model, and that both short- and long-range interactions are responsible for the slow rate of H/D exchange.