Neutrophil-to-lymphocyte ratio and prognosis in patients undergoing percutaneous coronary intervention for acute coronary syndrome

OBJECTIVE

The purpose of this study was to characterize Acute Coronary Syndrome (ACS)-associated inflammation by investigating correlates of the neutrophil-to-lymphocyte ratio (NLR), a surrogate marker of inflammation, and its relation to 1-year mortality in a cohort of patients undergoing percutaneous coronary intervention (PCI) for ACS at a single institution.

METHODS

We performed a single-institution, retrospective, observational study of all-comer ACS patients who underwent PCI and were discharged home before the COVID-19 pandemic between September 23, 2011 and July 31, 2017 for who outcomes data were available.

RESULTS

NLRhigh group tended to be older, white patients, less likely to smoke, more likely to have a history of heart failure and cardiac arrest, higher creatinine values, lower LVEF, and higher CK-MB (a surrogate for infarct size). Linear regression model demonstrated a strong correlation between increasing NLR and white race (B = 1.103, p = 0.001, hemoglobin (B = -0.30, p < 0.001), peak CK-MB (B = 0.004, p = 0.02), LVEF (B = -0.048, p < 0.001), and serum creatinine (B = 0.47, p = 0.03). There were a total of 87 deaths at one year. NLR > 3.4 was associated with worse one-year survival post-PCI (91.4 % vs. 95.4 %, log-rank p < 0.004), which was confirmed on multivariate analysis.

CONCLUSION

Our data confirm the independent prognostic significance of inflammation to mortality after ACS and may provide some insight into the putative benefits of inflammation modulation.

The Relationship of Duffy Gene Polymorphism, High Sensitivity C-Reactive Protein, and Long-term Outcomes

Background

Black adults have higher incidence of all-cause death and worse cardiovascular outcomes when compared to other populations. The Duffy chemokine receptor is not expressed in a large majority of Black adults and the clinical implications of this are unclear.

Methods

Here, we investigated the relationship of Duffy receptor status, high-sensitivity C-reactive protein (hs-CRP), and long-term cardiovascular outcomes in Black members of two contemporary, longitudinal cohort studies (the Jackson Heart Study and Multi-Ethnic Study of Atherosclerosis). Data on 4,307 Black participants (2,942 Duffy null and 1,365 Duffy receptor positive, as defined using Single Nucleotide Polymorphism (SNP) rs2814778) were included in this analysis.

Results

Duffy null was not independently associated with elevated levels of serum hs-CRP levels once conditioning for known CRP locus alleles in linkage disequilibrium with the Duffy gene. Duffy null status was not found to be independently associated with higher incidence of all-cause mortality or secondary outcomes after adjusting for possible confounders in Black participants.

Conclusions

These findings suggest that increased levels of hs-CRP found in Duffy null individuals is due to co-inheritance of CRP alleles known to influence circulating levels hs-CRP and that Duffy null status was not associated with worse adverse outcomes over the follow-up period in this cohort of well-balanced Black participants.

Mixed Warm and Cold Autoimmune Hemolytic Anemia With Concomitant Immune Thrombocytopenia Following Recent SARS-CoV-2 Infection and Ongoing Rhinovirus Infection

Mixed-type autoimmune hemolytic anemia (AIHA) is a term used to describe hemolysis occurring in the context of both warm and cold reactive autoantibodies to red blood cells. Immune thrombocytopenia (ITP) is an acquired form of thrombocytopenia potentially complicated by hemorrhage due to autoantibodies reactive with platelets and megakaryocytes. Diagnosis of ITP requires exclusion of other known causes of thrombocytopenia. AIHA and ITP may be primary disorders or associated with lymphoproliferative, autoimmune, or viral infections. Here, we report a rare case of simultaneous mixed-type autoimmune hemolytic anemia with immune thrombocytopenia following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection treated with Paxlovid followed by Rhinovirus infection.

Higher- or Usual-Volume Feedings in Infants Born Very Preterm: A Randomized Clinical Trial

OBJECTIVE

To determine whether higher-volume feedings improve postnatal growth among infants born very preterm.

STUDY DESIGN

Randomized clinical trial with 1:1 parallel allocation conducted from January 2015 to June 2018 in a single academic medical center in the US. In total, 224 infants with a birth weight 1001-2500 g born at <32 weeks of gestation were randomized to higher-volume (180-200 mL/kg/d) or usual-volume (140-160 mL/kg/d) feedings after establishing full enteral feedings (≥120 mL/kg/d). The primary outcome was growth velocity (g/kg/d) from randomization to study completion at 36 weeks of postmenstrual age or hospital discharge if earlier.

RESULTS

Growth velocity increased among infants in the higher-volume group compared with the usual-volume group (mean [SD], 20.5 [4.5] vs 17.9 [4.5] g/kg/d; P < .001). At study completion, all measurements were higher among infants in the higher-volume group compared with the usual-volume group: weight (2365 [324] g, z score -0.60 [0.73] vs 2200 [308] g, z score -0.94 [0.71]; P < .001); head circumference (31.9 [1.3] cm, z score -0.30 [0.91] vs 31.4 [1.3] cm, z score -0.53 [0.84]; P = .01); length (44.9 [2.1] cm, z score -0.68 [0.88] vs 44.4 [2.0], z score -0.83 [0.84]; P = .04); and mid-arm circumference (8.8 [0.8] cm vs 8.4 [0.8] cm; P = .002). Bronchopulmonary dysplasia, patent ductus arteriosus, necrotizing enterocolitis, or other adverse outcomes did not differ between groups.

CONCLUSIONS

In infants born very preterm weighing 1001-2500 g at birth, higher-volume feedings increased growth velocity, weight, head circumference, length, and mid-arm circumference compared with usual-volume feedings without adverse effects.

TRIAL REGISTRATION

ClinicalTrials.gov; NCT02377050.

The Malay version of smartphone addiction scale: Development, factor structure and validation of a short form for Malaysian adolescents

INTRODUCTION

This study aimed to validate the Malay version of the short form Smartphone Addiction Scale (SAS-M-SF) and to examine its psychometric properties in a cohort of pre-university adolescents.

METHODS

We obtained the validity and reliability evidence for the SAS-M-SF using a group of 307 pre-university students in Universiti Putra Malaysia (UPM), Serdang, Selangor, Malaysia with a mean age of 18.4±0.2 years (70.4% female and 29.6% male). A questionnaire containing the Malay version of Smartphone Addiction Scale (SAS-M), the Malay version of the short form Smartphone Addiction Scale (SAS-M-SF), and the Malay version of the Internet Addiction Test (IAT-M) was administered on the adolescents.

RESULTS

The SAS-M-SF displayed good internal consistency (Cronbach's α=0.80). Using principle component analysis, we identified a 4-factor SAS-M-SF model. A significant correlation between the SAS-M-SF and the IAT-M was found, lending support for concurrent validity. The prevalence of smartphone addiction was 54.5% based on cut-off score of ≥36 with a sensitivity of 70.2% and a specificity of 72.5%.

CONCLUSIONS

The 10-item SAS-M-SF is a valid and reliable screening tool for smartphone addiction among adolescents. The scale can help clinicians or educators design appropriate intervention and prevention programs targeting smartphone addiction in adolescents at clinical or school settings.

Alzheimer's disease: insights for risk evaluation and prevention in the Chinese population and the need for a comprehensive programme in Hong Kong/China

With the ageing of the global population, China is projected to be impacted significantly by the rising number of patients with Alzheimer's disease (AD). A cure for AD is not yet available, so society should be prepared for an increasing AD-related burden. In this review, we examine this impending problem and provide overviews on (a) the magnitude of the problem of AD in Hong Kong/China in the near future; (b) the genetic and lifestyle risk factors that contribute to AD; (c) current diagnostic approaches and the potential of newly discovered genetic biomarkers for early detection; (d) medications, non-pharmacological interventions, and possible preventive measures; and (e) the need for social and psychological care from the community. In Hong Kong, primary care and AD-related support for at-risk individuals, patients, and caregivers are inadequate. A joint effort from the medical community, government, universities, non-governmental organisations/charities, and industry should initiate the development of a long-term programme for AD. Finally, we outline recommendations for the relevant parties to consider.

Cognitive Frailty and Its Association with Nutrition and Depression in Community-Dwelling Older People

BACKGROUND

Cognitive frailty is a condition where physical frailty and mild cognitive impairment (MCI) co-exist. It is associated with increased risk of dementia and dependency. Previous studies reported that malnutrition and depression are associated with physical frailty and MCI; however, their relationships with cognitive frailty remained to be explored. The aims of this study were to examine the association of nutrition and depression with cognitive frailty, in comparison to having physical frailty or MCI alone.

METHODS

This study employed a cross-sectional design. Data collection was conducted in the community settings on the older people without dementia. Dependent variables were cognitive frailty, physical frailty, and MCI. The independent variables were depression and nutrition. Multi-nominal regression was employed to examine the relationships between the dependent and independent variables. The associations were adjusted by four known co-variates, including age, gender, education and APOE ε4 carrier status.

RESULTS

A total of 185 participants were recruited from four community centres and one elderly hostel and completed the data collection. Approximately 44.9% of the older people with physical frailty and 82.5% of elderly with MCI belonged to cognitive frailty. Multi-nominal regression models showed that depression is positively associated with cognitive frailty and with physical frailty, but not associated with solely MCI. Nutrition is negatively associated with cognitive frailty, but not associated with physical frailty or MCI alone.

CONCLUSION

Cognitive frailty is associated with malnutrition and depression. Therapeutic interventions managing depression and malnutrition may focus the older people with cognitive frailty to improve efficacy and cost-effectiveness.

Exposure of neonatal mice to bromine impairs their alveolar development and lung function

The halogen bromine (Br₂) is used extensively in industry and stored and transported in large quantities. Its accidental or malicious release into the atmosphere has resulted in significant casualties. The pathophysiology of Br₂-induced lung injury has been studied in adult animals, but the consequences of Br₂ exposure to the developing lung are completely unknown. We exposed neonatal mouse littermates on postnatal day 3 (P3) to either Br₂ at 400 ppm for 30 min (400/30), to Br₂ at 600 ppm for 30 min (600/30), or to room air, then returned them to their dams and observed until P14. Mice exposed to Br₂ had decreased survival (S) and had decreased weight (W) at P14 in the 400/30 group (S = 63.5%, W = 6.67 ± 0.08) and in the 600/30 group (S = 36.1%, W = 5.13 ± 0.67) as compared with air breathing mice (S = 100%, W = 7.96 ± 0.30). Alveolar development was impaired, as evidenced by increased mean linear intercept at P14. At P14, Br₂ exposed mice also exhibited a decrease of arterial partial pressure of oxygen, decreased quasi-static lung compliance, as well as increased alpha smooth muscle actin mRNA and protein and increased mRNA for IL-1β, IL-6, CXCL1, and TNFα. Global gene expression, evaluated by RNA sequencing and Ingenuity Pathway Analysis, revealed persistent abnormalities in gene expression profiles at P14 involving pathways of "formation of lung" and "pulmonary development." The data indicate that Br₂ inhalation injury early in life results in severe lung developmental consequences, wherein persistent inflammation and global altered developmental gene expression are likely mechanistic contributors.

Prevalence and factors associated with internet addiction among medical students - A cross-sectional study in Malaysia

INTRODUCTION

Internet is important to university students, especially for medical students who use it to search for literature and relevant information. However, some of the users are experiencing a gradual loss of the ability to reduce the duration and frequency of their internet activities, despite the negative consequences. The literature on internet usage among Malaysian medical students is limited. This study aims to determine the prevalence and factors associated with internet usage among medical students in a public university in Malaysia.

METHODS

This cross-sectional study was performed among all the medical students (Year 1-5). Students were assessed on their internet activities using the internet addiction questionnaires (IAT). A Multiple Logistic Regression was used for data analysis.

RESULTS

The study was conducted among 426 students. The study population consisted of 156 males (36.6%) and 270 females (63.4%). The mean age was 21.6 ±1.5 years. Ethnicity distribution among the students was: Malays (55.6%), Chinese (34.7%), Indians (7.3%) and others (2.3%). According to the IAT, 36.9% of the study sample was addicted to the internet. Using the multivariate logistic regression analysis, we have found that the use of internet access for entertainment purposes (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.05-12.00), male students (OR 1.8, 95% CI 1.01-3.21) and increasing frequency of internet usage were associated with internet addiction (OR 1.4, 95% CI 1.09- 1.67).

CONCLUSION

Internet addiction is a relatively frequent phenomenon among medical students. The predictors of internet addiction were male students using it for surfing and entertainment purposes.

Fibrotic-like changes in degenerate human intervertebral discs revealed by quantitative proteomic analysis

OBJECTIVE

Intervertebral disc degeneration (IDD) can lead to symptomatic conditions including sciatica and back pain. The purpose of this study is to understand the extracellular matrix (ECM) changes in disc biology through comparative proteomic analysis of degenerated and non-degenerated human intervertebral disc (IVD) tissues of different ages.

DESIGN

Seven non-degenerated (11-46 years of age) and seven degenerated (16-53 years of age) annulus fibrosus (AF) and nucleus pulposus (NP) samples were used. Proteins were extracted using guanidine hydrochloride, separated from large proteoglycans (PGs) by caesium chloride (CsCl) density gradient ultracentrifugation, and identified using liquid chromatography (LC) coupled with tandem mass spectrometry (MS/MS). For quantitative comparison, proteins were labeled with iTRAQ reagents. Collagen fibrils in the NP were assessed using scanning electron microscopy (SEM).

RESULTS

In the AF, quantitative analysis revealed increased levels of HTRA1, COMP and CILP in degeneration when compared with samples from older individuals. Fibronectin showed increment with age and degeneration. In the NP, more CILP and CILP2 were present in degenerated samples of younger individuals. Reduced protein solubility was observed in degenerated and older non-degenerated samples correlated with an accumulation of type I collagen in the insoluble fibers. Characterization of collagen fibrils in the NP revealed smaller mean fibril diameters and decreased porosity in the degenerated samples.

CONCLUSIONS

Our study identified distinct matrix changes associated with aging and degeneration in the intervertebral discs (IVDs). The nature of the ECM changes, together with observed decreased in solubility and changes in fibril diameter is consistent with a fibrotic-like environment.

Anhedonia among patients with Major Depressive Disorder: A comparison between patients on escitalopram and healthy controls

BACKGROUND AND AIMS

Escitalopram has widely been recognized as one of the most frequently used antidepressants, with superior tolerability and great efficacy in preventing major depressive disorder (MDD) relapse and recurrence. However, anhedonia, which is a core symptom of MDD, remains difficult to treat. This study investigates the hedonic levels of MDD patients treated with Escitalopram.

MATERIALS AND METHODS

A total of 108 participants, 26 of whom with MDD on Escitalopram, were recruited in this cross sectional study. They were evaluated using the Snaith-Hamilton Pleasure Scale (SHAPS) and Beck Depression Inventory (BDI) questionnaires to assess their hedonic state, general mental health condition and level of depression.

RESULTS

Our study shows that most items in the SHAPS scores are significantly different between MDD patients on Escitalopram and the controls.

CONCLUSIONS

The hedonic capacity remains different between the two groups despite patients with MDD are put on Escitalopram treatment. Escitalopram fails to alleviate the hedonic state of MDD patients. Antidepressants that improve both depressive symptoms and hedonic states should be considered when treating MDD patients in clinical settings.

Molecular-cloning of the human cycg1 gene encoding a g-type cyclin - overexpression in human osteosarcoma cells

Cyclins constitute a growing family of regulatory proteins that complex with, and activate, protein kinases involved in cell cycle control. Dysregulation of cyclin expression and/or cyclin-dependent kinase (cdk) activities may play a pivotal role in oncogenesis. In this report, we characterize a novel human cyclin gene by molecular cloning. This gene, designated CYCG1, encodes a human homologue of the rat G-type cyclin, exhibiting structural features and conserved sequence motifs of identified G(1) cyclins. The CYCG1 gene is expressed constitutively in synchronized human WI-38 fibroblasts and MG-63 osteosarcoma cells, which is reminiscent of CLN3 in Saccharomyces cerevisiae. Marked overexpression of CYCG1 is observed in a subset of human osteosarcoma cells, providing a potential link to cancer.

Inter-rater reliability between musculoskeletal radiologists and orthopedic surgeons on computed tomography imaging features of spinal metastases

INTRODUCTION

The primary objective of this pilot study was to examine the inter-rater reliability in scoring the computed tomography (ct) imaging features of spinal metastases in patients referred for radiotherapy (rt) for bone pain.

METHODS

In a retrospective review, 3 musculoskeletal radiologists and 2 orthopedic spinal surgeons independently evaluated ct imaging features for 41 patients with spinal metastases treated with rt in an outpatient radiation clinic from January 2007 to October 2008. The evaluation used spinal assessment criteria that had been developed in-house, with reference to osseous and soft tissue tumour extent,presence of a pathologic fracture,severity of vertebral height loss, andpresence of kyphosis.The Cohen kappa coefficient between the two specialties was calculated.

RESULTS

Mean patient age was 69.2 years (30 men, 11 women). The mean total daily oral morphine equivalent was 73.4 mg. Treatment dose-fractionation schedules included 8 Gy/1 (n = 28), 20 Gy/5 (n = 12), and 20 Gy/8 (n = 1). Areas of moderate agreement in identifying the ct imaging appearance of spinal metastasis included extent of vertebral body involvement (κ = 0.48) and soft-tissue component (κ = 0.59). Areas of fair agreement included extent of pedicle involvement (κ = 0.28), extent of lamina involvement (κ = 0.35), and presence of pathologic fracture (κ = 0.20). Areas of poor agreement included nerve-root compression (κ = 0.14) and vertebral body height loss (κ = 0.19).

CONCLUSIONS

The range of agreement between musculoskeletal radiologists and orthopedic surgeons for most spinal assessment criteria is moderate to poor. A consensus for managing challenging vertebral injuries secondary to spinal metastases needs to be established so as to best triage patients to the most appropriate therapeutic modality.

Environmental Applications of Xanes: Speciation of Tc In Cement After Chemical Treatment and Se After Bacterial Uptake

XANES (X-ray Absorption Near Edge Spectroscopy) has been employed to evaluate the efficacy of a process designed to encapsulate and reduce TcO4-in cement matrices, thereby immobilizing Tc. The oxidation state of Se following bioremediation of Se by bacteria has also been determined by XANES. The XANES measurements were performed at the Stanford Synchrotron Radiation Laboratory (SSRL) and the National Synchrotron Light Source (NSLS) at the respective K edges of Tc (21.0 keV) and Se (12.7 keV). Comparison of the XANES spectra of Tc in untreated cement to Tc in slag treated cement and to the chemical shifts of reference materials, shows that the oxidation state of Tc is the same in both cements. Thus, the addition of a reducing agent to the cement formulation does not significantly reduce the TcO4-. The common soil bacterium,Bacillus subtilis, is known to incorporate Se on or within the cell wall when exposed to a Se(IV) solution. The Se XANES spectra ofB. subtilis, as well as bacillus isolated from selenium rich soil, show that the organisms reduce selenite to the red allotrope of elemental Se.

Percutaneous cementoplasty of lytic metastasis in left acetabulum

Minimally invasive procedures such as percutaneous cementoplasty can provide immediate pain relief and can restore mechanical stability for patients with bone metastases who are not candidates for surgery or who show resistance to radiotherapy or analgesic treatment. Here, we examine a case of percutaneous cementoplasty to treat a lytic lesion of the acetabulum from breast cancer. Good filling was observed, and no complications occurred. A research assistant recorded the patient’s scores on the Karnofsky Performance Scale, Townsend Functional Assessment Scale, and Brief Pain Inventory before surgery and at days 1, 2, and 4 and weeks 1, 2, and 4 post-procedure. Improvement in pain and walking ability was demonstrated within the first 48 hours of treatment, and that improvement remained constant throughout follow-up. These findings echo the literature, in that percutaneous cementoplasty provides immediate and long-term pain relief with few complications. We recommend that percutaneous cementoplasty be used as an additional tool for palliative treatment of patients with bone metastases.

New multidisciplinary prostate bone metastases clinic: first of its kind in Canada

Prostate cancer is the most common non-skin malignancy in men. Almost all men who die from prostate cancer have hormone-refractory prostate cancer with metastasis to bone. Emerging supportive treatments—including chemotherapy, bisphosphonates, and surgery—require integration that is optimized in a multidisciplinary setting. A multidisciplinary clinic for bone metastases has been in place at Toronto–Sunnybrook Regional Cancer Centre since 1999, combining orthopedic surgery, radiation oncology, interventional radiology, and palliative medicine for all patients with bone metastases. The addition of a prostate-focused multidisciplinary clinic integrates these services for patients with advanced prostate cancer.

Two cases of acrometastasis to the hands and review of the literature

This paper reports two cases of acrometastasis to the hands. The first case involved a 78-year-old woman with a permeative osteolytic lesion in her proximal second metacarpal. A biopsy of this lesion suggested a diagnosis of non-small-cell lung carcinoma with secondary osseous metastasis. This was the first presentation of the woman’s primary diagnosis. A single 8-Gy fraction of palliative radiotherapy was delivered to the patient’s left hand. The treatment proved successful: the woman soon experienced pain relief and regained the use of her hand. The second case involved a 69-year-old woman with extensive lytic destruction involving the proximal two thirds of her third metacarpal. This patient had been diagnosed with carcinoma of the breast in 1990. She also received a single 8-Gy fraction of radiation, which improved both her pain and her hand mobility.

An extensive review of the literature uncovered 257 previously reported cases of acrometastasis. Articles were analyzed based on age and sex of the patient, site of the primary carcinoma, metastatic locations within the hand and affected appendage or appendages, the treatment given, and the patient’s length of survival. Men were almost twice as likely to experience acrometastasis as women, and the median age of the patients overall was 58 years (range: 18 months–91 years). Lung, kidney, and breast carcinoma were the three most prevalent primary diagnoses reported in the literature. Cancers of the colon, stomach, liver, prostate, and rectum affected the remainder of the population.

Overall, the right hand was more often host to the metastatic lesions. In addition, almost 10% of the patients experienced lesions in both hands. The third finger was the digit most affected by osseous metastases reported in the literature. Lesions of the thumb, fourth finger, second finger, and fifth finger were less commonly reported. The region of the digit most often affected within the patient population was the distal phalanx. The metacarpal bones, proximal phalanges, and middle phalanges comprised the remainder of the four most frequent acrometastatic sites. In the literature, single lesions were more prevalent than multiple bony lesions.

Based on the reported cases, amputation appeared to be the preferred method of treatment. Radiation, excision, and systemic therapy were the next most frequently used treatments. Patient survival was not well documented within the literature. However, the median survival of patients in the reported cases was 6 months. Thus, our review suggested that a diagnosis of hand metastasis is an indication of poor prognosis.

This report serves to emphasize the importance of properly diagnosing acrometastases. Identifying and effectively treating these metastases in a timely manner can lead to a dramatic improvement in a patient’s quality of life.

The do-not-resuscitate order: incidence of documentation in the medical records of cancer patients referred for palliative radiotherapy

Patients with symptomatic metastases referred for outpatient palliative radiotherapy for symptom control at the Rapid Response Radiotherapy Program (RRRP) and the Bone Metastases Clinic (BMC) at the Toronto-Sunnybrook Regional Cancer Centre have a limited life expectancy. Relevant medical information is missing from the files of many referred patients when they arrive at the clinics, potentially causing delayed treatment and ambiguity in the best management of their needs in situations of worsening condition. Clear documentation of the do-not-resuscitate (DNR) order is imperative to avoid panic and the taking of unnecessarily aggressive measures in situations in which cardiopulmonary resuscitation (CPR) has no benefit or is not desired. Here, we report the current practices of CPR code status documentation for patients referred to the RRRP and the BMC for out-patient palliative radiotherapy.We reviewed referral notes and accompanying medical records for 209 consecutive patients seen in the RRRP and the bmc during May-August 2004 for documentation of CPR-related advance directives. Patient demographics and cancer history were also recorded.Only 13 (6.2%) of the 209 patients had any documented reference to CPR code status. Of these 13 patients, 8 were DNR-coded, and 5 were full code. As compared with patients having no documented cpr code status, patients with documented status were significantly older (median age: 77 years; p = 0.0347), had poorer performance status (median Karnofsky performance status score: 40; p = 0.0001), and were more likely to be referred hospital inpatients (69%, p = 0.0004).Only a small proportion of symptomatic advanced cancer patients had any documentation of CPR code status upon referral for outpatient palliative radiotherapy. In future, our clinics plan to request information about CPR code status on our referral form.

Optimization of resolution and sensitivity of 4D NOESY using multi-dimensional decomposition

Highly resolved multi-dimensional NOE data are essential for rapid and accurate determination of spatial protein structures such as in structural genomics projects. Four-dimensional spectra contain almost no spectral overlap inherently present in lower dimensionality spectra and are highly amenable to application of automated routines for spectral resonance location and assignment. However, a high resolution 4D data set using conventional uniform sampling usually requires unacceptably long measurement time. Recently we have reported that the use of non-uniform sampling and multi-dimensional decomposition (MDD) can remedy this problem. Here we validate accuracy and robustness of the method, and demonstrate its usefulness for fully protonated protein samples. The method was applied to 11 kDa protein PA1123 from structural genomics pipeline. A systematic evaluation of spectral reconstructions obtained using 15-100% subsets of the complete reference 4D 1H-13C-13C-1H NOESY spectrum has been performed. With the experimental time saving of up to six times, the resolution and the sensitivity per unit time is shown to be similar to that of the fully recorded spectrum. For the 30% data subset we demonstrate that the intensities in the reconstructed and reference 4D spectra correspond with a correlation coefficient of 0.997 in the full range of spectral amplitudes. Intensities of the strong, middle and weak cross-peaks correlate with coefficients 0.9997, 0.9965, and 0.83. The method does not produce false peaks. 2% of weak peaks lost in the 30% reconstruction is in line with theoretically expected noise increase for the shorter measurement time. Together with good accuracy in the relative line-widths these translate to reliable distance constrains derived from sparsely sampled, high resolution 4D NOESY data.

Photodynamic therapy for the treatment of metastatic lesions in bone: studies in rat and porcine models

This study represents the first reported use of photodynamic therapy (PDT) for metastatic bone lesions and specifically, as a treatment for spinal metastases. A model of bone metastasis in rat confirmed the efficacy of benzoporphyrin derivative-monoacid-mediated PDT for treating lesions within the spine and appendicular bone. Fluorimetry confirmed the selective accumulation of drug into the tumor(s) at 3 h post-injection. 48 h post-light delivery into the vertebral body of the rat spine loss of bioluminescent signal and histological analyses of sectioned spine confirmed MT-1 tumor cell kill in vivo as previously confirmed in vitro using an established cell viability assay. Porcine vertebrae provided a model comparable to that of human for light propagation and PDT response. Histological examination of vertebrae 48 h post-PDT revealed a necrotic radius of 0.6 cm with an average fluence rate of 4.3 mW/cm2. Non-necrotic tissue damage was evident up to 2 cm out from the treatment fiber. Results support the application of PDT to the treatment of primary or metastatic lesions within bone.

Statin use in Type 2 diabetes mellitus is associated with a delay in starting insulin

AIMS

It has been suggested that HMG Co-A reductase inhibitors ('statins') may reduce the risk of developing Type 2 diabetes mellitus. This study was designed to evaluate whether use of statins would also delay progression to insulin therapy.

METHODS

This was a retrospective cohort study using Saskatchewan Health databases to identify subjects newly started on oral antidiabetic agents from 1991 to 1996.

SUBJECTS

< 30 years of age or with previous lipid-lowering drug use were excluded. Medications known to influence glycaemic control, co-morbidity, and demographic data were collected. Statin exposure was defined as at least 1 year of use. Primary outcome was starting insulin treatment. Multivariate Cox proportional hazards models were used to examine the association between statin use and starting insulin.

RESULTS

The final cohort included 10,996 new users of oral antidiabetic agents, of which 484 (4.4%) used statins. Mean age was 64 years and 55% were male. Mean duration of follow-up was 5.1 years; 11.1% (n = 1221) eventually started insulin treatment. Statin users were no less likely than non-users to start insulin treatment eventually (11.6% vs. 11.1%, P = 0.74). After multivariate adjustment, however, statin use was associated with a 10-month delay before newly treated diabetic subjects needed to start insulin treatment (adjusted hazard ratio 0.74; 95% confidence interval 0.56, 0.97, P = 0.028).

CONCLUSION

The use of statins is associated with a delay in starting insulin treatment in patients with Type 2 diabetes initially treated with oral antidiabetic agents. Whether this relationship exists for patients at high risk of developing diabetes should be examined in a randomized trial.

NMR structure determination and structure-based functional characterization of conserved hypothetical protein MTH1175 from Methanobacterium thermoautotrophicum

The solution structure of MTH1175, a 124-residue protein from the archaeon Methanobacterium thermoautotrophicum has been determined by NMR spectroscopy. MTH1175 is part of a family of conserved hypothetical proteins (COG1433) with unknown functions which contains multiple paralogs from all complete archaeal genomes and the archaeal gene-rich bacterium Thermotoga maritima. Sequence similarity indicates this protein family may be related to the nitrogen fixation proteins NifB and NifX. MTH1175 adopts an alpha/beta topology with a single mixed beta-sheet, and contains two flexible loops and an unstructured C-terminal tail. The fold resembles that of Ribonuclease H and similar proteins, but differs from these in several respects, and is not likely to have a nuclease activity.

Integrin-linked kinase, a promising cancer therapeutic target: biochemical and biological properties

Integrin-linked kinase (ILK) is an ankyrin repeat-containing Ser/Thr kinase that interacts with the cytoplasmic domains of beta(1) and beta(3) integrins. ILK is widely expressed in tissues throughout the body, and, as might be expected, appears to mediate a diversity of functions relating to its role in coupling integrins and growth factor receptors to downstream signaling pathways. Through its downstream targets protein kinase B/Akt and glycogen synthase kinase-3beta, ILK appears to be involved in several oncogenesis-related events, including suppression of apoptosis and promotion of cell survival, as well as cell migration and invasion. Over-expression of ILK in epithelial cells results in anchorage-independent cell growth with increased cell cycle progression. Inoculation of nude mice with ILK over-expressing cells leads to tumor formation. Furthermore, increased ILK expression and activity have been correlated with malignancy in several human tumor types, including breast, prostate, brain, and colon carcinomas. Based on these findings, ILK represents an excellent therapeutic target for the prevention of tumor progression. Here, we provide an overview of the physical and biochemical properties of ILK, and present data describing the impact of small-molecule ILK inhibitors on several ILK-mediated cellular functions.

Integrin-linked kinase, a promising cancer therapeutic target: biochemical and biological properties

Integrin-linked kinase (ILK) is an ankyrin repeat-containing Ser/Thr kinase that interacts with the cytoplasmic domains of beta(1) and beta(3) integrins. ILK is widely expressed in tissues throughout the body, and, as might be expected, appears to mediate a diversity of functions relating to its role in coupling integrins and growth factor receptors to downstream signaling pathways. Through its downstream targets protein kinase B/Akt and glycogen synthase kinase-3beta, ILK appears to be involved in several oncogenesis-related events, including suppression of apoptosis and promotion of cell survival, as well as cell migration and invasion. Over-expression of ILK in epithelial cells results in anchorage-independent cell growth with increased cell cycle progression. Inoculation of nude mice with ILK over-expressing cells leads to tumor formation. Furthermore, increased ILK expression and activity have been correlated with malignancy in several human tumor types, including breast, prostate, brain, and colon carcinomas. Based on these findings, ILK represents an excellent therapeutic target for the prevention of tumor progression. Here, we provide an overview of the physical and biochemical properties of ILK, and present data describing the impact of small-molecule ILK inhibitors on several ILK-mediated cellular functions.

Statistical model relating CA3 burst probability to recovery from burst-induced depression at recurrent collateral synapses

When neuronal excitability is increased in area CA3 of the hippocampus in vitro, the pyramidal cells generate periodic bursts of action potentials that are synchronized across the network. We have previously provided evidence that synaptic depression at the excitatory recurrent collateral synapses in the CA3 network terminates each population burst so that the next burst cannot begin until these synapses have recovered. These findings raise the possibility that burst timing can be described in terms of the probability of recovery of this population of synapses. Here we demonstrate that when neuronal excitability is changed in the CA3 network, the mean and variance of the interburst interval change in a manner that is consistent with a timing mechanism comprised of a pool of exponentially relaxing pacemakers. The relaxation time constant of these pacemakers is the same as the time constant describing the recovery from activity-dependent depression of recurrent collateral synapses. Recovery was estimated from the rate of spontaneous transmitter release versus time elapsed since the last CA3 burst. Pharmacological and long-term alterations of synaptic strength and network excitability affected CA3 burst timing as predicted by the cumulative binomial distribution if the burst pace-maker consists of a pool of recovering recurrent synapses. These findings indicate that the recovery of a pool of synapses from burst-induced depression is a sufficient explanation for burst timing in the in vitro CA3 neuronal network. These findings also demonstrate how information regarding the nature of a pacemaker can be derived from the temporal pattern of synchronous network activity. This information could also be extracted from less accessible networks such as those generating interictal epileptiform discharges in vivo.

Phenotypic differentiation of TGF-beta1-responsive pluripotent premesenchymal prehematopoietic progenitor (P4 stem) cells from murine bone marrow

On the horizon of modern molecular medicine is the requisite technology to capture multipotent human stem cells that are capable of self-renewal and to direct these stem cells along defined lineages for therapeutic purposes. In this article, we describe the hematopoietic and mesenchymal differentiation potential of a unique population of transforming growth factor-beta1 (TGF-beta1)-responsive stem cells derived from murine bone marrow. Stringent selection of the stem cells was accomplished under low serum conditions by virtue of an inherent survival response to a TGF-beta1-vWF fusion protein that was bound to collagen matrices. The TGF-beta1-responsive stem cells initially exhibited a non-adherent and uniformly blastoid morphology, underwent expansion into colonies upon serum reconstitution, and were capable of overt cytodifferentiation along fibrogenic, osteogenic, chondrogenic, or adipogenic lineages upon growth factor stimulation. Remarkably, these stem cells also underwent rapid expansion in the presence of either hematopoietic stem cell factor (SCF) or interleukin3 (IL-3), and differentiated into myeloid and lymphoid phenotypes upon exposure to the latter. Taken together, these results support the hypothesis that pluripotent premesenchymal prehematopoietic progenitor cells, designated P4 stem cells, are present postnatally in murine bone marrow and, thus, may be summarily isolated for various cell-based experimental therapies.

Diffusion and calibration properties of microdialysis sampling membranes in biological media

The diffusion and calibration properties for three commercially available microdialysis membranes (polycarbonate-polyether (PC), polyacrylonitrile (PAN), and cuprophan (CUP)) were evaluated. The analytes studied had molecular weights between 94 (phenol) and 1355 (vitamin B12). For each analyte-membrane pair, an effective membrane diffusion coefficient was calculated. Effective membrane diffusion coefficients varied considerably between the microdialysis membranes. For Vitamin B12, CUP and PAN membranes gave relative recovery values of greater than 20% at 0.5 microl min(-1), while the PC membrane had a 1% recovery. When backpressure was applied. PC and PAN membranes exhibited more ultrafiltration than CUP membranes. Ultrafiltration did not affect analyte relative recovery through either PC or PAN membranes. Effective membrane diffusion coefficients were not significantly altered for some membrane-analyte combinations when exposed to 4% bovine serum albumin or 0.3% fibrinogen. These data suggest that reductions in relative recovery during long-term microdialysis sampling experiments may be due to other physiologically relevant proteins or to tissue reactions near the dialysis membrane.