Distinct Cardiac Connexin-43 Expression in Hypertrophied and Atrophied Myocardium May Impact the Vulnerability of the Heart to Malignant Arrhythmias. A Pilot Study.

Our and other studies suggest that myocardial hypertrophy in response to hypertension and hyperthyroidism increases propensity of the heart to malignant arrhythmias, while these are rare in conditions of hypothyroidism or type-1 diabetes mellitus associated with myocardial atrophy. One of the crucial factors impacting the susceptibility of the heart to life-threatening arrhythmias is gap junction channel protein connexin-43 (Cx43), which ensure cell-to-cell coupling for electrical signal propagation. Therefore, we aimed to explore Cx43 protein abundance and its topology in hypertrophic and hypotrophic cardiac phenotype. Analysis were performed in left ventricular tissue of adult male spontaneously hypertensive rat (SHR), Wistar Kyoto rats treated for 8-weeks with L-thyroxine, methimazol or strepotozotocin to induce hyperthyroid, hypothyroid and type-1 diabetic status as well as non-treated animals. Results showed that comparing to healthy rats there was a decrease of total myocardial Cx43 and its variant phosphorylated at serine368 in SHR and hyperthyroid rats. Besides, enhanced localization of Cx43 was demonstrated on lateral sides of hypertrophied cardiomyocytes. In contrast, total Cx43 protein and its serine368 variant were increased in atrophied left ventricle of hypothyroid and type-1 diabetic rats. It was associated with less pronounced alterations in Cx43 topology. In parallel, the abundance of PKCepsilon, which phosphorylates Cx43 at serine368 that stabilize Cx43 function and distribution was reduced in hypertrophied heart while enhanced in atrophied once. Findings suggest that differences in the abundance of cardiac Cx43, its variant phosphorylated at serine368 and Cx43 topology may explain, in part, distinct propensity of hypertrophied and atrophied heart to malignant arrhythmias.

Simplified novel prognostic score for real-life older adults with multiple myeloma-registry-based analysis.

The main goal was to find a simple prognostic to evaluate overall survival of patients older than 65 years of age with myeloma. Retrospective registry-based analysis from the Registry of Monoclonal Gammopathies was conducted. Patients over 65 years with symptomatic myeloma were included. The four major parameters with impact on survival were identified: male gender, age > 75, creatinine > 152 µmol/L, and ECOG performance status 2-4. The patients were scored as good (0 points), intermediate good (1 point), intermediate poor (2 points), poor (3-4 points). Patients (1410 MM) were included. Median OS (months) was 65.7 (95% CI 49.8-81.7) for good, 51.0 (44.1-57.8) for intermediate good, 32.2 (26.2-38.2) for intermediate poor, and 18.9 (15.1-22.7) for poor. The differences in OS were statistically significant (p < 0.0001). Good score was used as reference for hazard ratios, which for each other score were 1.43 (1.09-1.84) for intermediate good, 2.58 (2.00-3.33) for intermediate poor, and 3.88 (2.94-5.10) for poor. Time to progression showed medians (months) 20.5 (17.4-62.4) for good, 19.3 (17.0-21.7) for intermediate good, 19.6 (16.2-23.0) for intermediate poor, and 13.0 (10.8-15.2) for poor. The suggested scoring system provides readily available information about the prognosis of MM patients above 65 years.

Intravenous thrombolysis in wake-up stroke: real-world data from the Austrian Stroke Unit Registry.

BACKGROUND AND PURPOSE: Data on real-world experience with intravenous thrombolysis (IV tPA) in wake-up stroke (WUS) are limited. The aim of this study was to examine the efficacy and safety of IV tPA in patients with WUS included in the Austrian Stroke Unit Registry. METHODS: Data from a large nationwide stroke unit registry including initial stroke severity, vascular risk factors, comorbidities, treatment with IV tPA, symptomatic intracerebral haemorrhage (sICH) and functional outcome were extracted and analysed. Patients with WUS were compared with patients with known-onset stroke (KOS) regarding the frequency of IV tPA treatment, neurological improvement (National Institutes of Health Stroke Scale score ≥4), sICH and 3-month functional outcome by modified Rankin Scale score using standard statistical tests. RESULTS: A total of 107 895 stroke patients entered the analysis, including 12 534 with WUS and 91 899 with KOS. Altogether, 904 (7.2%) patients with WUS received IV tPA as compared with 16 694 (18.2%) patients with KOS. Patients with WUS who received IV tPA treatment had twofold higher initial National Institutes of Health Stroke Scale score (median 8 vs. median 4) as compared with patients with KOS. There was no statistical difference in functional outcome by modified Rankin Scale score 0-1 at 3 months between patients with WUS and patients with KOS treated with IV tPA (adjusted odds ratio, 1.08; 95% confidence interval, 0.9-1.31). Also, the rate of sICH did not differ (4.1% vs. 4%, P = 0.852). CONCLUSIONS: In this large non-randomized comparison, the safety and efficacy of IV tPA in patients with WUS in the real-world setting seems to be comparable to patients with KOS.

Beta-blocker therapy is not associated with mortality after intracerebral hemorrhage.

BACKGROUND: Beta-blocker therapy has been suggested to have neuroprotective properties in the setting of acute stroke; however, the evidence is weak and contradictory. We aimed to examine the effects of pre-admission therapy with beta-blockers (BB) on the mortality following spontaneous intracerebral hemorrhage (ICH). METHODS: Retrospective analysis of the Helsinki ICH Study database. RESULTS: A total of 1013 patients with ICH were included in the analysis. Patients taking BB were significantly older, had a higher premorbid mRS score, had more DNR orders, and more comorbidities as atrial fibrillation, hypertension, diabetes mellitus, ischemic heart disease, and heart failure. After adjustment for age, pre-existing comorbidities, and prior use of antithrombotic and antihypertensive medications, no differences in in-hospital mortality (OR 1.1, 95% CI 0.8-1.7), 12-month mortality (OR 1.3, 95% CI 0.9-1.9), and 3-month mortality (OR 1.2, 95% CI 0.8-1.7) emerged. CONCLUSION: Pre-admission use of BB was not associated with mortality after ICH.

TAPP or TEP for Recurrent Inguinal Hernia? Population-Based Analysis of Prospective Data on 1309 Patients Undergoing Endoscopic Repair for Recurrent Inguinal Hernia.

BACKGROUND: Whether total extraperitoneal inguinal hernia repair (TEP) is associated with worse outcomes compared to transabdominal preperitoneal inguinal hernia repair (TAPP) for the treatment of recurrent inguinal hernia continues to be a matter of debate. The objective of this large cohort study is to compare complications, conversion rates and postoperative length of hospital stay between patients undergoing TEP or TAPP for unilateral recurrent inguinal hernia repair. METHOD: Based on prospective data of the Swiss Association of Laparoscopic and Thoracoscopic Surgery, all patients who underwent elective TEP or TAPP for unilateral recurrent inguinal hernia between 1995 and 2006 were included. The following outcomes were compared: conversion rates, intraoperative complications, surgical postoperative complications and duration of operation. RESULTS: Data on 1309 patients undergoing TEP (n = 1022) and TAPP (n = 287) for recurrent inguinal hernia were prospectively collected. Average age, BMI and ASA score were similar in both groups. Patients undergoing TEP had a significantly increased rate of intraoperative complications (TEP 6.3 % vs. TAPP 2.8 %, p = 0.0225). Duration of operation was longer for patients undergoing TEP (TEP 80.3 vs. TAPP 73.0 min, p < 0.0023) while postoperative length of hospital stay was longer for patients undergoing TAPP (TEP 2.6 vs. TAPP 3.1 day, p = 0.0145). Surgical postoperative complications (TEP 3.52 % vs. TAPP 2.09 %, p = 0.2239), general postoperative complications (TEP 1.47 % vs. TAPP 0.7 %, p = 0.3081) and conversion rates (TEP 2.15 % vs. TAPP 1.39 %, p = 0.4155) were not significantly different. CONCLUSION: This study is the first population-based analysis comparing outcomes of patients with recurrent inguinal hernia undergoing TEP versus TAPP in a prospective cohort of over 1300 patients. Intraoperative complications were significantly higher in patients undergoing TEP. The TEP technique was associated with longer operating times, but a shorter postoperative length of hospital stay. Nonetheless, the absolute outcome differences are small and thus, on a population-based level, both techniques appear to be safe and effective for patients undergoing endoscopic repair for unilateral recurrent inguinal hernia.

[Anakinra treatment in Schnitzler syndrome -  results of the first retrospective multicenter study in six patients from the Czech Republic]. / Lécba anakinrou u Schnitzler syndromu -  výsledky první retrospektivní multicentrické studie sesti pacientu z Ceské republiky.

BACKGROUND: Schnitzler syndrome is a very rare, acquired, autoinflammatory disease of mostly adult onset with characteristic combination of chronic recurrent urticaria and monoclonal immunoglobulin M or G gammopathy predisposing the patients to malignant lymphoproliferation. In this work, we analyzed the results of bio-logical therapy with anakinra on a national level aiming to supply data for effective pharmaco-economic estimates, lay the grounds of nationwide patient registry, raise awareness among professional public and optimize provided health care. PATIENTS AND METHODS: The retrospective study (10/ 2006- 9/ 2013) included six males with definite Schnitzler syndrome verified by the new Strasbourg criteria. All patients were pretreated with antihistamines, nonsteroidal antiinflammatory drugs and glucocorticoids. Four patients underwent two or more treatment lines including intravenous bisphosphonates, 2- chlorodeoxyadenosine (cladribine), interferonα, PUVA photochemotherapy, cyclosporine A, thalidomide, bortezomib, chlorambucil, cyclophosphamide, colchicine and methotrexate. Anakinra monotherapy was initiated in standard dosing (100 mg subcutaneously daily). RESULTS: Complete and partial remissions were achieved in five (83%) and one patients (17%), respectively. Complete remission was characterized by urticaria and pain regression (within hours), normalization of inflammatory markers (with--in days) and bone metabolism improvement assessed by the markers of osteoblastic osteoformation and osteoclastic osteoresorption in one case (within weeks). With normalized inflammatory markers (including interleukin6 and interleukin18), arthralgia and sporadic exacerbations of urticaria and fevers persist in the patient in partial remission with proven Q703K polymorphism in NLRP3 gene. The median treatment followup was 30.5 months (37.2 ± 31.2 (n = 6)). The dosing interval was prolonged in one case of complete remission to 48 hours. No serious adverse reactions occurred during anakinra application. CONCLUSION: In Schnitzler syndrome, anakinra represents an effective, verified and safe medication with potentionally longterm administration not compromising its original efficacy and subjective tolerance. Anakinra, blocking autonomous inflammatory reaction of the organism via interleukin1 pathway, is a generally accepted first line treatment that should be made available in standard dosing for all Schnitzler patients.

Cerebral vasospasm and delayed cerebral ischemia in intraventricular hemorrhage.

BACKGROUND: Intracerebral hemorrhage (ICH) with intraventricular extension (IVH) is a devastating disease with a particular high mortality. In some aspects, IVH may resemble subarachnoid hemorrhage. The incidence and role of cerebral vasospasm in ICH with IVH are poorly understood. Here, we aimed to analyze the incidence and relationship of cerebral vasospasm to clinical characteristics, in-hospital mortality, and functional outcome at 3 months in patients suffering ICH with IVH. METHODS: Patients with ICH and IVH treated on a neurological intensive care unit were prospectively enrolled in a single-center observational study. Vasospasm was defined using established ultrasound criteria. Delayed cerebral ischemia (DCI) was defined as a new hypodensity on follow-up cranial CT. Functional outcome at 3 months was assessed using the modified Rankin Scale. RESULTS: 129 patients with ICH and IVH were screened for the study. 62 patients entered the final analysis. The incidence of significant vasospasm was 37 %. A strong trend was found for the association between all cerebral vasospasm and DCI (P = 0.046). Early (up to 48 h) vasospasm was significantly associated with a DCI (P = 0.033). Overall mortality and outcome after 3 months did not differ between the groups. CONCLUSION: Cerebral vasospasm seems to be a frequent complication after ICH with IVH and might be associated with DCI. Larger studies are warranted to confirm this hypothesis.

Microalbuminuria: a potential prognostic marker for acute stroke.

INTRODUCTION: Stroke is potentially preventable through risk factor reduction. Over the past decade, the role of microalbuminuria (MA) as a risk factor for chronic diseases has become apparent. The aim of this study was to determine the prognostic value of MA in acute stroke patients. MATERIALS AND METHODS: Patients with acute ischemic stroke admitted to our stroke unit were included in this study. Clinical history and vascular risk factors were recorded. Severity of stroke and outcome were assessed by NIHSS and modified Rankin scale (mRS) upon admission and discharge. Urinary albumin excretion was measured in 24-h urine samples. Multivariate analysis was performed to investigate predictors of poor outcome. RESULTS: MA was found in 43% of 138 patients and was associated with elevated levels of C-reactive protein (CRP), glucose at baseline, and HbA1c; higher rates of diabetes mellitus and atrial fibrillation; higher systolic blood pressure; greater age; and higher premorbid mRS, NIHSS upon admission/discharge, and mRS upon discharge. In a multivariate analysis, MA (OR 5.07, 95%CI 2.18-11.77; p = 0.004), premorbid mRS (OR 2.030, 95%CI 1.369-3.011; p = 0.0001), and NIHSS upon admission (OR 1.116, 95%CI 1.044-1.193; p = 0.001) were independent predictors of poor outcome upon discharge. CONCLUSION: MA was frequently found in acute ischemic stroke patients. It was associated with severe neurological deficit upon admission and severe functional impairment upon discharge. MA in the acute phase was shown to be an independent predictor of poor outcome. The association between MA and CRP levels points to potential linkage of MA to the inflammatory response in acute stroke.

Association of non-diabetic hyperglycemia with autonomic shift in acute ischaemic stroke.

BACKGROUND AND PURPOSE: The etiology of hyperglycemia in acute stroke remains controversial. It is unclear whether hyperglycemia arises as an epiphenomenon of stroke or as a reflection of underlying diabetes. Autonomic shift to sympathetic overactivity has been repeatedly observed in acute stroke. We hypothesize that hyperglycemia in acute stroke relates to autonomic imbalance and that the respective deleterious effects on stroke outcome may be cross-linked. METHODS: A total of 75 non-diabetic patients with ischaemic stroke were included in a prospective study. Glucose levels at admission, fasting glucose, and glucose profiles were recorded. Autonomic function was quantified by the assessment of spontaneous baroreflex sensitivity (BRS) using a cross-correlation method. Demographic and clinical data including stroke volumes and admission National Institute of Heath Stroke Scale scores were included into the analysis. Functional outcome at 90 days was assessed using the modified Rankin Scale. RESULTS: Hyperglycemia was correlated with decreased BRS independent of stroke severity or volume (r = -0.46, P < 0.001). In two separate regression models, glucose levels and BRS independently predicted unfavorable outcome at 3 months (OR = 1.06, CI = 1.02-1.11, P = 0.004 and OR = 0.75, CI = 0.56-0.99, P = 0.04). However, combining the models, only glucose levels (OR = 1.06, CI = 1.02-1.11, P = 0.004) remained independent predictor of outcome at 3 months. CONCLUSIONS: We observed an association between hyperglycemia and decreased BRS in non-diabetic patients, suggesting that hyperglycemic reaction in acute stroke may reflect stroke-related autonomic changes. Moreover, outcome effects of autonomic changes and hyperglycemia seem to be interdependent, putatively having the sympatho-vagal imbalance as common underlying mechanism. The possible therapeutic relevance of this finding warrants further studies.

Loss of Penumbra by Impaired Oxygen Supply? Decreasing Hemoglobin Levels Predict Infarct Growth after Acute Ischemic Stroke: Stroke: Relevant Impact of Hemoglobin, Hematocrit and Transfusion (STRAIGHT) - An Observational Study.

BACKGROUND: The association of mortality and poor outcome with reduced levels of hemoglobin (Hb) and hematocrit (Hct) in patients admitted for ischemic stroke was recently demonstrated. The mechanisms behind this have remained unclear. AIMS: Here, we aimed to investigate a putative association between low Hb and Hct levels and infarct growth. METHODS: All consecutive patients who received intravenous thrombolysis based on multimodal magnetic resonance imaging during the years 1998-2009 were screened. Laboratory data as well as admission magnetic resonance images and follow-up computed tomography scans of 257 patients were assessed. Overall, data of 100 patients were of sufficient quality and further analyzed. RESULTS: Decrease in Hb and Hct as well as perfusion-weighted imaging volume, mismatch volume, and final infarct size on follow-up computed tomography were associated with infarct growth. A linear regression model revealed Hb decrease (ß = 0.23, p = 0.02) to be a predictor of infarct growth, independent of mismatch volume (ß = 0.27, p = 0.004) and minimum sodium (ß = -0.21, p = 0.03), and adjusted to the non-predicting variables age, National Institute of Health Stroke Scale score, maximum leucocytes and C-reactive protein, blood glucose, and Hct decrease. CONCLUSION: Hb levels that decrease after admission independently predict infarct growth in thrombolyzed stroke patients. The clinical implications of this relationship remain to be investigated.

[Intensive care management [corrected] of patients with intracerebral hemorrhage]. / Intensivmedizinische Versorgung von Patienten mit intrazerebraler Blutung.

Approximately 10-15% of acute strokes are caused by non-aneurysmatic intracerebral hemorrhage (ICH) and incidences are expected to increase due to an aging population. Studies from the 1990s estimated mortality of ICH to be as high as 50%. However, these figures may partly be attributed to the fact that patients suffering from ICH frequently received only supportive therapy and the poor prognosis may therefore be more a self-fulfilling prophecy. Recently it has been shown that treatment in a specialized neurological intensive care unit alone was associated with better outcomes after ICH. In recent years considerable efforts have been undertaken in order to develop new therapies for ICH and to assess them in randomized controlled trials. Apart from admission status, hemorrhage volume is considered to be the main prognostic factor and impeding the spread of the hematoma is thus a basic therapeutic principle. The use of activated factor VIIa (aFVIIa) to stop hematoma enlargement has been assessed in two large randomized controlled trials, however the promising results of the dose-finding study could not be confirmed in a phase III trial. Although hemostatic therapy with aFVIIa reduced growth of the hematoma it failed to improve clinical outcome. Similar results were found in a randomized controlled trial on blood pressure management in acute ICH. The link between reduction of hematoma growth and improved outcome is therefore still lacking. Likewise the value of surgical hematoma evacuation remains uncertain. In the largest randomized controlled trial on surgical treatment in ICH so far, only a small subgroup of patients with superficial hemorrhages seemed to benefit from hematoma evacuation. Whether improved intensive care can contribute to improved outcome after ICH will be shown by data obtained in the coming years.

Common disorders in the neurological emergency room--experience at a tertiary care hospital.

BACKGROUND: The profile of patients with neurological diseases referred to specialized emergency rooms (ER) has not been reported and it is unknown whether a setting of decentralized ERs is associated with a high number of referrals because of inappropriate admissions. METHODS: In this prospective study, consecutive patients of a specialized neurological ER were enrolled. Data encompassed time from symptom onset to admission, discharge diagnoses, data on hospitalization and on transfers to and from other ERs. RESULTS: Thousand seven hundred and forty-three patients were enrolled. Most common diagnoses were cerebrovascular events (26.5%), headache disorders (13%) and seizures (12.7%). Time since onset of symptoms depended on who referred the patient (P<0.001); seizure patients presented earlier than other patients (P<0.001) and 30.5% of patients with cerebrovascular events presented within 3 h after symptom onset but did not present sooner than patients with other diagnoses. In 18%, diagnoses did not match neurological disorders, 4.5% of patients suffered from cardiovascular events. Referrals to and from other ERs rarely occurred (10.3% vs. 5.9%). Only 20 patients with acute cerebrovascular events were referred via other ERs (1.1%). CONCLUSION: A system of a specialized neurological ER can quickly clear up uncertainties in interpreting neurological symptoms. Owing to the rising number of neurological patients in ERs, more studies are urgently needed comparing the different organizational forms for emergency services.

Microalbuminuria in cerebrovascular disease: a modifiable risk factor?

Stroke is potentially preventable through risk factor modification. Over the past decade, there has been considerable interest on microalbuminuria as a risk factor for chronic diseases. The concept of microalbuminuria was originally introduced, about 25 years ago, to clinical practice as a useful marker of nephropathy. Since then various studies reported an association of microalbuminuria with the increased risk of cardiovascular events and all cause of mortality in subjects with or without diabetes. The presence of microalbuminuria was related to left ventricular dysfunction, stroke, and myocardial infarction. Microalbuminuria may be a predictor of stroke but further studies are required. However data on prognostic significance and therapeutic consequence, particularly in haemorrhagic stroke are lacking. This review focuses on the importance of microalbuminuria for cerebrovascular disease, stressing the clinical and therapeutic implications using antihypertensive therapy to control the urinary albumin excretion.

[Obesity surgery--useful knowledge in indication and follow up]. / Adipositaschirurgie--Wissenswertes zu Indikation und Nachsorge.

In the last years, obesity has become one of the main problems of health care systems in Western countries. Among morbid obese patients, four out of five will develop comorbidities doubling the mortality risk in women and increase the numbers in men at a threefold risk. According to evidence based guidelines, nowadays surgery is the best and most effective treatment resulting in excellent long-term weight loss, reduction of comorbidities while extending expectation of life. A sound indication is the most important step for successful surgery. In this paper we focus on Swiss regulations and some special indications which have to be taken into consideration. After bariatric surgery clinical follow up on a regular basis is also of great importance. Furthermore, we explain typical mechanical and nutritional complications after different types of surgery and give some recommendations.

Intensive care management of acute stroke: general management.

For a long time, patients with severe stroke were facing therapeutic nihilism of the attending physicians. Implementation of do-not-resuscitate-orders may have lead to self-fulfilling prophecies and to a pessimistic overestimation of prognosis of severe stroke syndromes. However, there have been great advances in intensive care management of acute stroke patients and it has been shown that treatment on a specialised neurological intensive care unit improves outcome. In this review, we will present a summary of the current state-of-the-art intensive care management of acute stroke patients. After presenting an overview on general management of stroke intensive care patients, special aspects of neurological intensive care of acute large middle cerebral artery stroke, intracerebral haemorrhage and subarachnoid haemorrhage will be discussed. In part II of the review, surgical management options for acute stroke will be discussed in detail.

Adrenoleukodystrophy--a new mutation identified.

INTRODUCTION: X-linked adrenoleukodystrophy from the group of peroxisomal disorders presents with an extensive spectrum of phenotypes. The mutation affects the ABCD1 gene encoding a peroxisomal membrane protein. So far, its detailed function has not been clarified. However, it plays an essential role in the ethiopathogenesis of X-linked adrenoleukodystrophy. Its defect causes accumulation of the very long chain fatty acids in the tissues of the central and peripheral nervous system, adrenal glands and in the body fluids. PURPOSE: To review the clinical presentations and diagnostic issues in X-adrenoleukodystrophy diagnosed in the one affected family. METHODS: A case report. Measurement of very long chain fatty acids. Molecular analysis of the adrenoleukodystrophy gene. RESULTS: A new "unique" mutation in the initiation codon in the first'exon of ABCD1 gene was identified. We present a phenotype description of a patient with this mutation. CONCLUSIONS: X-linked adrenoleukodystrophy is a disease with the incidence rate approximately 1:16,800. Detection of new mutations contributes to better understanding of this rare disease and makes the diagnostic more available and precise. The importance of an adequate diagnosis is justified not only by a different therapeutic approach, but also by the need of prenatal diagnostics and the need of genetic counselling in the affected families. As demonstrated in our case, it is necessary to consider this diagnosis also in the adult age, e.g. within the differential diagnosis of spastic paraparesis (Tab. 1, Fig. 4, Ref 23). Full Text (Free, PDF) www.bmrj.sk.

Hydrogen-bonding interactions in the active sites of cytochrome P450cam and its site-directed mutants.

Resonance Raman spectroscopy is applied to the cyanide adducts of cytochrome P450cam and its T252A and D251N site-directed mutants, both in their substrate-free and camphor-bound forms, to probe active-site heme structure and, in particular, interactions of the FeCN fragment with potential active-site H-bond donors. In contrast to the ferrous CO and ferric NO adducts, which form only essentially linear (slightly distorted) FeXY fragments, the spectra of the ferric CN(-) adducts provide clear evidence the for the existence of an additional, rather highly bent, conformer; that is, the cyanide complexes form both linear and bent conformers in both the substrate-free and substrate-bound forms. Formation of this bent conformer is most reasonably attributed to the presence of off-axis H-bond donors, which induce distortion on the FeCN fragment but not the FeCO and FeNO fragments, which are poorer H-bond acceptors. For all three proteins, the substrate-free form exhibits a complex spectral pattern which arises because one of the modes associated with the FeCN fragment is coupled with two heme macrocycle deformation modes. Significantly, no evidence for such coupling is observed in the spectra of the camphor-bound forms. While various unknown factors may possibly give rise to selective activation of such coupling in the substrate-free derivative, given the known facts about the active-site architecture of this enzyme, a plausible explanation is that the bent conformer is oriented toward the water-filled substrate-binding site in the substrate-free form, but oppositely, toward the proposed proton delivery shuttle, in the substrate-bound form. Sensitivity of the FeCN modes to H(2)O/D(2)O exchange in the two camphor-bound mutants, which is apparently absent for the camphor-bound native protein, is most reasonably attributed to the known presence of extra water in the active sites of these mutants.

G1-Cdk activity is required for both proliferation and viability of cytokine-dependent myeloid and erythroid cells.

Hematopoietic cytokines are critically required for survival and cell proliferation of myeloid and erythroid progenitors. It is poorly understood how the apoptotic machinery of progenitor cells senses the absence of specific cytokines. Here we show that G1-Cdk activity is essential for cytokine-mediated viability of myeloid and erythroid progenitors. Cytokine deprivation is associated with rapid downregulation of G1-Cdk activity, cell cycle arrest, and apoptosis. Specific inhibition of G1-Cdk activity results in apoptotic cell death in the presence of saturating cytokine levels. In contrast, specific cell cycle arrest in G2/M does not affect viability. When cell proliferation is arrested by cytokine withdrawal, primary erythroid progenitors expressing v-ErbA maintain G1-Cdk activity and undergo delayed apoptosis. Cdk-inhibitors strongly enhance apoptosis in starved v-ErbA cells, indicating that sustained Cdk activity is required for protection from apoptosis by v-ErbA.

Method to recover a lipophilic drug from hydroxypropyl methylcellulose matrix tablets.

A reverse-phase high-performance liquid chromatographic (HPLC) method for recovery of the lipophilic drug, alprazolam, from matrix tablets containing the hydrophilic polymer hydroxypropyl methylcellulose (HPMC) was developed. Lipophilic drugs, such as alprazolam, are difficult to completely extract and quantitate from tablets containing HPMC polymer. The percentage of recoveries of alprazolam from placebo powder spiked with alprazolam stock solution and from placebo powder mixed with alprazolam powder were about 100% and 85% to 95%, respectively. The validated method using water to completely dissolve HPMC before the addition of a strong solvent to dissolve and extract the drug from the HPMC solution was shown to be the most reproducible method. Different molecular weight distributions of the HPMC polymer, such as HPMC-K4M and HPMC-K100LV, did not influence the dissolution results of alprazolam using this validated method. Similarly, the excipients composing the matrix tablet formulations, such as dicalcium phosphate dihydrate, dicalcium phosphate anhydrous, calcium sulfate dihydrate, sucrose, dextrose, and lactose monohydrate, did not influence the percent recovery of alprazolam. The recovery method reported herein was shown to be the most efficient to achieve complete recovery of alprazolam from powder blends and tablets containing a variety of excipients and different grades of HPMC.