High throughput screen of small molecules as potential countermeasures to galactic cosmic radiation induced cellular dysfunction

Space travel increases galactic cosmic ray exposure to flight crews and this is significantly elevated once travel moves beyond low Earth orbit. This includes combinations of high energy protons and heavy ions such as ⁵⁶Fe or ¹⁶O. There are distinct differences in the biological response to low-energy transfer (x-rays) or high-energy transfer (High-LET). However, given the relatively low fluence rate of exposure during flight operations, it might be possible to manage these deleterious effects using small molecules currently available. Virtually all reports to date examining small molecule management of radiation exposure are based on low-LET challenges. To that end an FDA approved drug library (725 drugs) was used to perform a high throughput screen of cultured cells following exposure to galactic cosmic radiation. The H9c2 myoblasts, ES-D3 pluripotent cells, and Hy926 endothelial cell lines were exposed to a single exposure (75 cGy) using the 5-ion GCRsim protocol developed at the NASA Space Radiation Laboratory (NSRL). Following GCR exposure cells were maintained for up to two weeks. For each drug (@10µM), a hierarchical cumulative score was developed incorporating measures of mitochondrial and cellular function, oxidant stress and cell senescence. The top 160 scores were retested following a similar protocol using 1µM of each drug. Within the 160 drugs, 33 are considered to have an anti-inflammatory capacity, while others also indirectly suppressed pro-inflammatory pathways or had noted antioxidant capacity. Lead candidates came from different drug classes that included angiotensin converting enzyme inhibitors or AT1 antagonists, COX2 inhibitors, as well as drugs mediated by histamine receptors. Surprisingly, different classes of anti-diabetic medications were observed to be useful including sulfonylureas and metformin. Using a hierarchical decision structure, we have identified several lead candidates. That no one drug or even drug class was completely successful across all parameters tested suggests the complexity of managing the consequences of galactic cosmic radiation exposure.

The role of imaging in malignant pleural mesothelioma: an update after the 2018 BTS guidelines

Malignant pleural mesothelioma (MPM) is a primary malignancy of the pleura and is associated with a poor outcome. The symptoms and signs of malignant mesothelioma present late in the natural history of the disease and are non-specific, making the diagnosis challenging and imaging key. In 2018, the British Thoracic Society (BTS) updated the guideline on diagnosis, staging, and follow-up of patients with MPM. These recommendations are discussed in this review of the current literature on imaging of MPM. It is estimated MPM will continue to cause serious morbidity and mortality in the UK late into the 21st century, and internationally, people continue to be exposed to asbestos. We aim to update the reader on current and future imaging strategies, which could aid early diagnosis of pleural malignancy and provide an update on staging and assessment of tumour response.

Prenatal genetic carrier screening in the genomic age

The Society for Maternal-Fetal Medicine, American College of Obstetricians and Gynecologists (ACOG), and American College of Medical Genetics and Genomics (ACMG) held a workshop entitled "Prenatal Genetic Testing" on January 25, 2017 to address several questions arising from the increasing implementation of preconception and prenatal expanded carrier screening (ECS). ECS allows for identification of a greater number of genetic sequencing changes (not all of which cause disease) and simultaneous testing for an increased number of genetic conditions without limitation to specific ethnic groups. The workshop participants reached consensus on the following: ethnicity based testing cannot be completely abandoned in favor of panethnic ECS; the specific approach to screening should be a patient's choice and not driven solely by provider preference; organizations should work to develop a framework for vetting conditions that should be reported on ECS panels; compared with prenatal screening, preconception screening is ideal and, at this time, due to the costs and the need for timeliness associated with prenatal screening posttest counseling and testing, that when ECS is offered it should be presented as a preconception option; preconception and prenatal panels should be identical across the spectrum of patients, including those undergoing assisted reproduction; adult-onset conditions should not be included on ECS panels; partners should be offered next-generation sequencing to identify rare variants when the first partner screened is determined to be a carrier; re-screening in subsequent pregnancies is not indicated, despite the potential for expansion of carrier screening conditions and variants; and more education about ECS for providers and patients is necessary to implement prenatal carrier screening in a responsible way.

Prenatal detection of 10q22q23 duplications: dilemmas in phenotype prediction

OBJECTIVES

The phenotype for 10q22q23 duplication is diverse, ranging from intellectual disability and dysmorphism to normal development. Interpreting the clinical significance of the duplication identified in this region is difficult, especially in the prenatal setting. This study aimed to characterize the prenatal findings associated with this submicroscopic imbalance and discuss the dilemmas in predicting the phenotype of 10q22q23 duplications.

METHODS

This is a retrospective study of three cases of 10q22q23 duplications diagnosed prenatally by chromosomal microarray analysis. Detailed pregnancy outcome and pediatric follow-up were documented.

RESULTS

The genotypic and phenotypic features of the reported cases were discussed. 10q22q23 duplications are associated with an unpredictable and variable phenotypic outcome. Despite there was no phenotype found to be shared by 50% of the duplication cases, congenital heart defects, hypotelorism, and developmental delays including speech and motor delay seem to be more common.

CONCLUSIONS

The phenotype of 10q22q23 duplication is highly variable prenatally and postnatally. Identification of additional affected individuals with similar duplications is needed to provide further insights into the pathogenesis of this microduplication. © 2016 John Wiley & Sons, Ltd.

G9a histone methyltransferase inhibitor BIX01294 promotes expansion of adult cardiac progenitor cells without changing their phenotype or differentiation potential

OBJECTIVES

As a follow-up to our previous reports showing that the G9a histone methyltransferase-specific inhibitor BIX01294 enhances bone marrow cell cardiac potential, this drug was examined for its effects on cardiomyocytes and mouse cardiac progenitor cells (CPCs).

MATERIALS AND METHODS

Cardiomyocytes and cardiac explants were cultured ± BIX01294, and examined for changes in cardiac function, protein and gene expression. Additionally, enriched populations of CPCs, contained in the 'phase bright cell' component of explants, were harvested from non-treated and BIX01294-treated cardiac tissue, and assayed for differences in cell phenotype and differentiation potential. Mouse CPCs were cultured with rat cardiomyocytes to allow differentiation of the progenitors to be assayed using species-specific PCR primers.

RESULTS

While BIX01294 had no discernible effect on myocyte function and sarcomeric organization, treatment with this drug significantly increased CPC proliferation, as indicated by enhanced MTT metabolization and BrdUrd incorporation (4.1- and 2.0-fold, respectively, P < 0.001) after 48 h labelling, and increased Ki67 expression (4.8-fold, P < 0.001) after 7 days culture. Heart explants exposed to BIX01294 generated 3.6-fold (P < 0.005) greater yields of CPCs by 2 weeks culture. Importantly, CPCs obtained from non-treated and BIX01294-treated cultures did not differ in phenotype or differentiation potential.

CONCLUSIONS

These data indicate that BIX01294 can expand CPCs without undermining their capacity as cardiac progenitors, and suggest that this drug may have utility for generating large numbers of CPCs for cardiac repair.

Protocol for PIT: a phase III trial of prophylactic irradiation of tracts in patients with malignant pleural mesothelioma following invasive chest wall intervention

INTRODUCTION

Histological diagnosis of malignant mesothelioma requires an invasive procedure such as CT-guided needle biopsy, thoracoscopy, video-assisted thorascopic surgery (VATs) or thoracotomy. These invasive procedures encourage tumour cell seeding at the intervention site and patients can develop tumour nodules within the chest wall. In an effort to prevent nodules developing, it has been widespread practice across Europe to irradiate intervention sites postprocedure--a practice known as prophylactic irradiation of tracts (PIT). To date there has not been a suitably powered randomised trial to determine whether PIT is effective at reducing the risk of chest wall nodule development.

METHODS AND ANALYSIS

In this multicentre phase III randomised controlled superiority trial, 374 patients who can receive radiotherapy within 42 days of a chest wall intervention will be randomised to receive PIT or no PIT. Patients will be randomised on a 1:1 basis. Radiotherapy in the PIT arm will be 21 Gy in three fractions. Subsequent chemotherapy is given at the clinicians' discretion. A reduction in the incidence of chest wall nodules from 15% to 5% in favour of radiotherapy 6 months after randomisation would be clinically significant. All patients will be followed up for up to 2 years with monthly telephone contact and at least four outpatient visits in the first year.

ETHICS AND DISSEMINATION

PIT was approved by NRES Committee North West-Greater Manchester West (REC reference 12/NW/0249) and recruitment is currently on-going, the last patient is expected to be randomised by the end of 2015. The analysis of the primary end point, incidence of chest wall nodules 6 months after randomisation, is expected to be published in 2016 in a peer reviewed journal and results will also be presented at scientific meetings and summary results published online. A follow-up analysis is expected to be published in 2018.

TRIAL REGISTRATION NUMBER

ISRCTN04240319; NCT01604005; Pre-results.

Expanded carrier screening in reproductive medicine-points to consider: a joint statement of the American College of Medical Genetics and Genomics, American College of Obstetricians and Gynecologists, National Society of Genetic Counselors, Perinatal Quality Foundation, and Society for Maternal-Fetal Medicine

The Perinatal Quality Foundation and the American College of Medical Genetics and Genomics, in association with the American College of Obstetricians and Gynecologists, the Society for Maternal-Fetal Medicine, and the National Society of Genetic Counselors, have collaborated to provide education for clinicians and laboratories regarding the use of expanded genetic carrier screening in reproductive medicine. This statement does not replace current screening guidelines, which are published by individual organizations to direct the practice of their constituents. As organizations develop practice guidelines for expanded carrier screening, further direction is likely. The current statement demonstrates an approach for health care providers and laboratories who wish to or who are currently offering expanded carrier screening to their patients.

Chronic ethanol consumption increases myocardial mitochondrial DNA mutations: a potential contribution by mitochondrial topoisomerases

AIMS

Alcoholic cardiomyopathy (ACM) presents as decreased myocardial contractility, arrhythmias and secondary non-ischemic dilated cardiomyopathy leading to heart failure. Mitochondrial dysfunction is known to have a significant role in the development and complications of ACM. This study investigated if chronic ethanol feeding promoted myocardial mitochondrial topoisomerase dysfunction as one underlying cause of mitochondrial DNA (mtDNA) damage and mitochondrial dysfunction in ACM.

METHODS

The impact of chronic ethanol exposure on the myocardial mitochondria was examined in both neonatal cardiomyocytes using 50 mM ethanol for 6 days and in rats assigned to control or ethanol feeding groups for 4 months.

RESULTS

Chronic ethanol feeding led to significant (P < 0.05) decreases in M-mode Fractional Shortening, ejection fraction, and the cardiac output index as well as increases in Tau. Ethanol feeding promoted mitochondrial dysfunction as evidenced by significantly decreased left ventricle cytochrome oxidase activity and decreases in mitochondrial protein content. Both in rats and in cultured cardiomyocytes, chronic ethanol presentation significantly increased mtDNA damage. Using isolated myocardial mitochondria, both mitochondrial topoisomerase-dependent DNA cleavage and DNA relaxation were significantly altered by ethanol feeding.

CONCLUSION

Chronic ethanol feeding compromised cardiovascular and mitochondrial function as a result of a decline in mtDNA integrity that was in part the consequence of mitochondrial topoisomerase dysfunction. Understanding the regulation of the mitochondrial topoisomerases is critical for protection of mtDNA, not only for the management of alcoholic cardiomyopathy, but also for the many other clinical treatments that targets the topoisomerases in the alcoholic patient.

The transnational alliance for genetic counseling: promoting international communication and collaboration

The Transnational Alliance for Genetic Counseling seeks to promote communication and collaboration among genetic counselor educators, internationally. Connecting and building global relationships among colleagues also promotes the development of the genetic counseling profession. Genetic counselors everywhere can achieve deeper understanding of their work by seeking international perspectives.

Type II diabetes increases mitochondrial DNA mutations in the left ventricle of the Goto-Kakizaki diabetic rat

Mitochondrial dysfunction has a significant role in the development of diabetic cardiomyopathy. Mitochondrial oxidant stress has been accepted as the singular cause of mitochondrial DNA (mtDNA) damage as an underlying cause of mitochondrial dysfunction. However, separate from a direct effect on mtDNA integrity, diabetic-induced increases in oxidant stress alter mitochondrial topoisomerase function to propagate mtDNA mutations as a contributor to mitochondrial dysfunction. Both glucose-challenged neonatal cardiomyocytes and the diabetic Goto-Kakizaki (GK) rat were studied. In both the GK left ventricle (LV) and in cardiomyocytes, chronically elevated glucose presentation induced a significant increase in mtDNA damage that was accompanied by decreased mitochondrial function. TTGE analysis revealed a number of base pair substitutions in the 3' end of COX3 from GK LV mtDNA that significantly altered the protein sequence. Mitochondrial topoisomerase DNA cleavage activity in isolated mitochondria was significantly increased in the GK LV compared with Wistar controls. Both hydroxycamptothecin, a topoisomerase type 1 inhibitor, and doxorubicin, a topoisomerase type 2 inhibitor, significantly exacerbated the DNA cleavage activity of isolated mitochondrial extracts indicating the presence of multiple functional topoisomerases in the mitochondria. Mitochondrial topoisomerase function was significantly altered in the presence of H2O2 suggesting that separate from a direct effect on mtDNA, oxidant stress mediated type II diabetes-induced alterations of mitochondrial topoisomerase function. These findings are significant in that the activation/inhibition state of the mitochondrial topoisomerases will have important consequences for mtDNA integrity and the well being of the diabetic myocardium.

Chronically elevated glucose compromises myocardial mitochondrial DNA integrity by alteration of mitochondrial topoisomerase function

Mitochondrial dysfunction has a significant role in the development and complications of diabetic cardiomyopathy. Mitochondrial dysfunction and mitochondrial DNA (mtDNA) mutations are also associated with different types of cancer and neurodegenerative diseases. The goal of this study was to determine if chronically elevated glucose increase in mtDNA damage contributed to mitochondrial dysfunction and identify the underlying basis for mtDNA damage. H9c2 myotubes (a cardiac-derived cell line) were studied in the presence of 5.5, 16.5, or 33.0 mM glucose for up to 13 days. Tests of mitochondria function (Complex I and IV activity and ATP generation) were all significantly depressed by elevated media glucose. Intramitochondrial superoxide and intracellular superoxide levels were transiently increased during the experimental period. AnnexinV binding (a marker of apoptosis) was significantly increased after 7 and 13 days of high glucose. Thirteen days of elevated glucose significantly increased mtDNA damage globally and across the region encoding for the three subunits of cytochrome oxidase. Using mitochondria isolated from cells chronically exposed to elevated glucose, we observed significant increases in topoisomerase-linked DNA cleavage. Mitochondria-dependent DNA cleavage was significantly exacerbated by H(2)O(2) and that immunoprecipitation of mitochondrial extracts with a mtTOP1 antibody significantly decreased DNA cleavage, indicating that at least part of this activity could be attributed to mtTOP1. We conclude that even mild increases in glucose presentation compromised mitochondrial function as a result of a decline in mtDNA integrity. Separate from a direct impact of oxidative stress on mtDNA, ROS-induced alteration of mitochondrial topoisomerase activity exacerbated and propagated increases in mtDNA damage. These findings are significant in that the activation/inhibition state of the mitochondrial topoisomerases will have important consequences for mitochondrial DNA integrity and the well being of the myocardium.

Narcoleptic orexin receptor knockout mice express enhanced cholinergic properties in laterodorsal tegmental neurons

Pharmacological studies of narcoleptic canines indicate that exaggerated pontine cholinergic transmission promotes cataplexy. As disruption of orexin (hypocretin) signaling is a primary defect in narcolepsy with cataplexy, we investigated whether markers of cholinergic synaptic transmission might be altered in mice constitutively lacking orexin receptors (double receptor knockout; DKO). mRNA for Choline acetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT) and the high-affinity choline transporter (CHT1) but not acetylcholinesterase (AChE) was significantly higher in samples from DKO than wild-type (WT) mice. This was region-specific; levels were elevated in samples from the laterodorsal tegmental nucleus (LDT) and the fifth motor nucleus (Mo5) but not in whole brainstem samples. Consistent with region-specific changes, we were unable to detect significant differences in Western blots for ChAT and CHT1 in isolates from brainstem, thalamus and cortex or in ChAT enzymatic activity in the pons. However, using ChAT immunocytochemistry, we found that while the number of cholinergic neurons in the LDT and Mo5 were not different, the intensity of somatic ChAT immunostaining was significantly greater in the LDT, but not Mo5, from DKO than from WT mice. We also found that ChAT activity was significantly reduced in cortical samples from DKO compared with WT mice. Collectively, these findings suggest that the orexins can regulate neurotransmitter expression and that the constitutive absence of orexin signaling results in an up-regulation of the machinery necessary for cholinergic neurotransmission in a mesopontine population of neurons that have been associated with both normal rapid eye movement sleep and cataplexy.

Lost in transition: challenges in the expanding field of adult genetics

It is increasingly clear that medical genetics has broad relevance in adult clinical medicine. More adult patients with genetic conditions are being recognized, genetic testing for adult-onset genetic conditions is expanding, and children with genetic conditions are now more likely to survive to adulthood. While the number of patients who could benefit from medical genetic services increases, adult care providers are less well educated about clinical genetics and are not sufficiently prepared to meet the growing needs of this population. Genetics professionals may also be ill-suited for this challenge, since geneticists and genetic counselors have traditionally had greater experience in pediatric and prenatal settings. Communication between primary care physicians who treat adults and the genetics community is currently suboptimal and the identification and subsequent referral of adult patients for genetic services need improvement. Finally, published guidelines that address how to deliver genetic services to adult patients are unavailable for many genetic conditions. In this article we address the challenges of transitioning genetics services from traditional, and largely pediatric-based models to paradigms that can best address the needs of adult patients with genetic conditions. Potential solutions and the practicality of implementation of a team-based approach to adult genetic medicine, including the application of genetic counseling, are also discussed.

EGFR expression: associations with outcome and clinicopathological variables in malignant pleural mesothelioma

Malignant mesothelioma (MM) is a fatal tumour of increasing incidence which is related to asbestos exposure. This work evaluated expression in MM of Epidermal Growth Factor Receptor (EGFR) by immunohistochemistry in 168 tumour sections and its correlations with clinicopathological and biological factors. The microvessel density (MVD) was derived from CD34 immunostained sections. Hematoxylin and eosin stained sections were examined for intratumoural necrosis. COX-2 protein expression was evaluated with semi-quantitative Western blotting of homogenised tumour supernatants (n=45). EGFR expression was correlated with survival by Kaplan-Meier and log rank analysis. Univariate and multivariate Cox proportional hazards models were used to compare the effects of EGFR with clinicopathological and biological prognostic factors and prognostic scoring systems. EGFR expression was identified in 74 cases (44%) and correlated with epithelioid cell type (p<0.0001), good performance status (p<0.0001), the absence of chest pain (p<0.0001) and the presence of TN (p=0.004), but not MVD or COX-2. EGFR expression was a good prognostic factor in univariate analysis (p=0.01). Independent indicators of poor prognosis in multivariate analysis were non-epithelioid cell type (p=0.0001), weight loss, performance status and WBC>8.3x10(9)L(-1). EGFR status was not an independent prognostic factor. EGFR expression in MM correlates with epithelioid histology and TN. EGFR may be a target for selective therapies in MM.

In Vivo beta-adrenergic activation of atrial natriuretic factor (ANF) reporter expression

Isoproterenol (ISO) infusion increases ANF-mRNA levels and control of ANF expression lies at the level of transcription. In neonatal cardiomyocytes, previous investigations determined that the -125 to -100 region of the rat ANF 5' flanking region contained cis-elements critical for control of ISO induced ANF transcription. However, it is unclear if these same cis-elements regulate ANF transcription in vivo. To examine this question, reporter plasmids containing the ANF 5' flanking/promoter region were injected directly into the left ventricle. Following a recovery period, osmotic pumps were implanted to infuse vehicle or ISO (0.2 or 2.0 mg/kg/d). ISO significantly (p < .05) increased the LV/BW ratio in a dose dependent, but not a time dependent manner. ISO significantly (p < .05) increased ANF reporter expression in both a dose-dependent and time dependent manner. Injections into the midwall of the LV or into the apex did not lead to significant differences in ISO-induced ANF reporter expression. Using site-specific mutations of ANF reporter constructs, comparisons were made of ISO induced ANF transcription in vitro in neonatal cardiomyocytes and in vivo in the adult heart. Cis-elements critical for ISO activation in cultured cardiomyocytes were not essential for the increased expression of the ANF reporters in vivo. The results indicate that distinct differences in ANF transcriptional regulation exist in vivo in the adult heart as compared with neonatal cardiomyocytes, and suggest the recruitment of other signaling pathways beyond adrenergic-receptor mediated pathways.

Constitutional mosaic trisomy 21 and azoospermia: a case report

Constitutional full trisomy 21 is a common disorder in which abnormal spermatogenesis has been previously described. However, constitutional mosaic trisomy 21 in an otherwise normal but infertile male has not been explored. We report a case with low level mosaic trisomy 21 in a non-syndrome but azoospermic patient. We also propose that the patient's azoospermia may be related to the constitutional mosaic trisomy 21 and thus resulting in a late onset of testicular failure.

En-bloc chest wall and lung resection for non-small cell lung cancer. Predictors of 60-day non-cancer related mortality

OBJECTIVE

Predictors for early mortality after isolated pulmonary resection have been identified and clear guidelines regarding fitness for surgery have been produced. However, the additional risk of en-bloc chest wall resection has not been extensively studied.

AIM

We analyzed our total experience of combined chest wall and lung resection for non-small-cell lung cancer (NSCLC) to identify additional risk factors for early non-tumour related mortality.

PATIENTS AND METHODS

A retrospective review of 41 consecutive patients, with median age of 69 (range 37-84) years, operated by a single surgeon over a 4-year period. Univariate analysis was performed to assess the relationship of selected preoperative and operative variables on mortality within 2 months from surgery.

RESULTS

Low preoperative body mass index, age over 75 years, and preoperative FEV(1) of less than 70% of predicted were associated with a significantly increased 60-day mortality. In those patients with any of these risk factors 60-day mortality was 47% (8 of 17). In those with none of the above there was no mortality (of 24 patients) (P=0.0004).

DISCUSSION

En-bloc pulmonary and chest wall resection for NSCLC should be avoided in the elderly, those with limited respiratory reserve or significant weight loss. These factors render the patient highly susceptible to chest complications leading to increased mortality.

Matrix metalloproteinases 2 and 9 (gelatinases A and B) expression in malignant mesothelioma and benign pleura

Matrix metalloproteinases (MMPs), in particular the gelatinases (MMP-2 and -9), play a significant role in tumour invasion and angiogenesis. The expression and activities of MMPs have not been characterised in malignant mesothelioma (MM) tumour samples. In a prospective study, gelatinase activity was evaluated in homogenised supernatants of snap frozen MM (n=35), inflamed pleura (IP, n=12) and uninflammed pleura (UP, n=14) tissue specimens by semiquantitative gelatin zymography. Matrix metalloproteinases were correlated with clinicopathological factors and with survival using Kaplan-Meier and Cox proportional hazard models. In MM, pro- and active MMP-2 levels were significantly greater than for MMP-9 (P=0.006, P<0.001). Active MMP-2 was significantly greater in MM than in UP (P=0.04). MMP-2 activity was equivalent between IP and MM, but both pro- and active MMP-9 activities were greater in IP (P=0.02, P=0.009). While there were trends towards poor survival with increasing total and pro-MMP-2 activity (P=0.08) in univariate analysis, they were both independent poor prognostic factors in multivariate analysis in conjunction with weight loss (pro-MMP-2 P=0.03, total MMP-2 P=0.04). Total and pro-MMP-2 also contributed to the Cancer and Leukemia Group B prognostic groups. MMP-9 activities were not prognostic. Matrix metalloproteinases, and in particular MMP-2, the most abundant gelatinase, may play an important role in MM tumour growth and metastasis. Agents that reduce MMP synthesis and/or activity may have a role to play in the management of MM.

Pharmacological characterization of ionotropic glutamate receptors in the zebrafish olfactory bulb

The distribution of N-methyl-D-aspartate- (NMDA) and kainic acid- (KA) sensitive ionotropic glutamate receptors (iGluR) in the zebrafish olfactory bulb was assessed using an activity-dependent labeling method. Olfactory bulbs were incubated with an ion channel permeant probe, agmatine (AGB), and iGluR agonists in vitro, and the labeled neurons containing AGB were visualized immunocytochemically. Preparations exposed to 250 microM KA in the presence of a NMDA receptor antagonist (D-2-amino-5-phosphono-valeric acid) and an alpha-amino-3-hydroxyl-5-methylisoxazole-4-propionic acid (AMPA) receptor antagonist (sym 2206), revealed KA receptor-mediated labeling of approximately 60-70% of mitral cells, juxtaglomerular cells, tyrosine hydroxylase-positive cells and granule cells. A higher proportion of ventral olfactory bulb neurons were KA-sensitive. Application of 333 microM NMDA in the presence of an AMPA/KA receptor antagonist (6-cyano-7-nitroquinoxaline-2,3-dione) resulted in NMDA receptor-mediated labeling of almost all neurons. The concentrations eliciting 50% of the maximal response (effective concentration: EC(50)s) for NMDA-stimulated labeling of different cell types were not significantly different and ranged from 148 microM to 162 microM. These results suggest that while NMDA receptors with similar binding affinities are widely distributed in the neurons of the zebrafish olfactory bulb, KA receptors are heterogeneously expressed among these cells and may serve unique roles in different regions of the olfactory bulb.

Can pneumonectomy for non-small cell lung cancer be avoided? An audit of parenchymal sparing lung surgery

BACKGROUND

Lung cancer resection rates are suboptimal in the UK. Pneumonectomy has a higher perioperative mortality risk than lobectomy. To increase resection rates and improve outcomes we have implemented a policy of parenchymal sparing surgery for tumours involving a main stem bronchus.

METHODS

In a prospective 4 year study of 119 consecutive patients operated upon by a single surgeon the perioperative course, pathology and survival were compared for 81 patients undergoing pneumonectomy and 38 patients in whom pneumonectomy was avoided by bronchoplastic+/-angioplastic procedures.

RESULTS

The rate of pneumonectomy decreased significantly with increasing experience with parenchymal sparing surgery (R(2)=0.98, P<0.001) with 21 of the last 30 patients (70%) avoiding pneumonectomy. There were no significant inter-group differences in patient characteristics, perioperative course or outcome. One-year survival was 64% after pneumonectomy and 73% after sleeve lobectomy. However the perioperative loss of respiratory function was significantly lower in the patients in whom pneumonectomy was avoided (P=0.0003).

CONCLUSIONS

Pneumonectomy can be avoided in a large proportion of patients with non-small cell lung cancer of a main stem bronchus without adversely affecting outcome but with preservation of lung function

Towards a biological staging model for operable non-small cell lung cancer

Non-small cell lung cancer is the most common cause of cancer-related death in North America and Europe. Despite improvements in the diagnosis and treatment of the disease the prognosis remains poor, the overall 5-year survival being 4-14%. An increased understanding of the molecular biology of the disease may identify novel targets for drug development. We evaluated epidermal growth factor receptor (EGFR), HER-2/neu, matrix metalloproteinase (MMP)-2, MMP-9, p53 and bcl-2 expression and microvessel density (MVD) in patients who underwent surgery with curative intent in our department between 1991 and 1996. Co-expression of EGFR/MMP-9, MVD and bcl-2 were found to be independent prognostic variables, which allowed prediction of patient outcome independent of surgical stage. Other prognostic factors identified in our series were gender, surgical stage, platelet count, extent of necrosis, the hypoxia marker carbonic anhydrase-9 and beta-catenin. In collaboration with groups in Oxford and Greece, we were also able to establish the angiogenic growth factors vascular endothelial growth factor and platelet-derived endothelial growth factor as prognostic variables. The inter-relationships between these factors are currently being examined in an expanded patient series. Through this work we hope to be able to construct an integrated biological prognostic model which can be tested in prospective studies. This work has identified several potential targets for novel therapeutic agents currently in development.

Pressure overload induces heterologous expression of the atrial natriuretic factor (ANF) gene

Several investigations have demonstrated the regional heterogeneity of myocardial phenotype, and hypertrophy may also induce regionally disparate changes. We have utilized the direct DNA injection technique to study regional variations in overload-induced ANF expression. Pressure overload was induced by stenosis of the ascending aorta in canines. ANF promoter reporters were injected into the left ventricle; in different regions including the base, the midwall region, and the apex. Injections were made at different depths to include the epicardial and endocardial layers. The animals were sacrificed 7 days following surgery and the left ventricle harvested for tissue analysis. Under normotensive conditions, ANF reporter expression was similar throughout the heart. PO increased ANF expression and the increases were greater in the endocardium than in the epicardium. PO also significantly increased expression in the midwall and base regions, but not in the apex. It is unknown from these experiments, whether the greater increases in midwall expression are a function of greater wall stress, metabolic demand, or phenotypic differences in the midwall myocytes. These findings do indicate that regional differences in overload-induced changes in gene expression are evident and may be functionally important in determining myocardial response to increased functional demand.

Palliative surgical debulking in malignant mesothelioma. Predictors of survival and symptom control

OBJECTIVE

Malignant mesothelioma (MM) typically presents at an advanced stage. In the UK surgical intervention has been mostly reserved for tissue diagnosis or chemical pleurodesis. However, the role of debulking surgery in symptom control has not been fully explored.

METHODS

In a prospective cohort study, 51 consecutive patients presenting with MM underwent palliative surgical debulking for symptomatic relief (all patients presented with dyspnoea, 39 also had pain and two had a co-existing pleural empyema). Patients with early disease who underwent extrapleural pneumonectomy were excluded. The treatment aims were pleural drainage, lung re-expansion, pleurodesis and pleural debulking for symptom control. If the lung re-expanded after drainage of the effusion a subtotal parietal pleurectomy was performed via Video Assisted Thoracic Surgery (VATS). If the lung remained entrapped, a parietal and visceral decortication using VATS or thoracotomy was performed. The changes in subjective dyspnoea and pain scores were recorded at 6 weeks and 3, 6 and 12 months after surgery. Prognostic factors were analyzed to determine their influence on survival and symptom control.

RESULTS

VATS pleurectomy was possible in 17 patients (34%), whilst decortication was required in the remainder (three by VATS and 31 by thoracotomy). Median postoperative stay was 7 days (range 2-17) with 30-day mortality of 7.8% (four of 51 patients). Morbidity included postoperative empyema in two patients (4%) and prolonged air-leak in five (9.8%). Overall significant symptomatic benefit was obtained up to 3 months after surgery but subsequently increasing mortality offset these benefits. Epithelial cell type and absence of weight loss prior to surgery were found to predict longer survival and successful symptom control.

CONCLUSIONS

Debulking surgery has a beneficial role in symptom control for unresectable MM. However, this surgery should be reserved for those patients who present with epithelial cell type and before significant loss of weight.

Lobar volume reduction surgery: a method of increasing the lung cancer resection rate in patients with emphysema

BACKGROUND

Guidelines on patient selection for lung cancer resection identify a predicted postoperative forced expiratory volume in 1 second (ppoFEV(1)) of <40% as a predictor of high risk. Experience with lung volume reduction surgery suggests that ppoFEV(1) may be underestimated in those with concomitant emphysema.

METHODS

Anatomical lobectomy was performed in 29 patients with a resectable lung cancer within a poorly perfused, hyperinflated emphysematous lobe identified by radionuclide perfusion scintigraphy and computed tomographic scanning. Perioperative changes in spirometric parameters at 3 months were compared in 14 patients (group A) of mean age 69 years (range 48-78) with ppoFEV(1) <40% (mean (SD) 31.4 (7)%) and 15 patients (group B) with ppoFEV(1) >40% (mean (SD) 47 (5)%). The correlation between predicted and actual postoperative FEV(1) was also assessed.

RESULTS

In group B there was a significant perioperative reduction in FEV(1) (p=0.01) but in group A FEV(1) did not change significantly after lobectomy (p=0.87); mean difference in perioperative change between groups A and B 331 ml (95% CI 150 to 510). Despite the difference in ppoFEV(1) between the groups, there was no difference in actual FEV(1) at 3 months. In-hospital mortality was 14% in group A and zero in group B, but at a median follow up of 12 (range 6-40) months there was no difference in survival between the groups.

CONCLUSIONS

Selection for lung cancer resection in patients with emphysema using standard calculations of ppoFEV(1) may be misleading. The effect of lobar volume reduction allows for an extension of the selection criteria.

Angiogenesis is an independent prognostic factor in malignant mesothelioma

Angiogenesis is essential for tumour growth beyond 1 to 2 mm in diameter. The clinical relevance of angiogenesis, as assessed by microvessel density (MVD), is unclear in malignant mesothelioma (MM). Immunohistochemistry was performed on 104 archival, paraffin-embedded, surgically resected MM samples with an anti-CD34 monoclonal antibody, using the Streptavidin-biotin complex immunoperoxidase technique. 93 cases were suitable for microvessel quantification. MVD was obtained from 3 intratumoural hotspots, using a Chalkley eyepiece graticule at x 250 power. MVD was correlated with survival by Kaplan-Meier and log-rank analysis. A stepwise, multivariate Cox model was used to compare MVD with known prognostic factors and the EORTC and CALGB prognostic scoring systems. Overall median survival from the date of diagnosis was 5.0 months. Increasing MVD was a poor prognostic factor in univariate analysis (P = 0.02). Independent indicators of poor prognosis in multivariate analysis were non-epithelial cell type (P = 0.002), performance status > 0 (P = 0.003) and increasing MVD (P = 0.01). In multivariate Cox analysis, MVD contributed independently to the EORTC (P = 0.006), but not to the CALGB (P = 0.1), prognostic groups. Angiogenesis, as assessed by MVD, is a poor prognostic factor in MM, independent of other clinicopathological variables and the EORTC prognostic scoring system. Further work is required to assess the prognostic importance of angiogenic regulatory factors in this disease.

Prognostic factors for malignant mesothelioma in 142 patients: validation of CALGB and EORTC prognostic scoring systems

BACKGROUND

The incidence of malignant mesothelioma is increasing. There is the perception that survival is worse in the UK than in other countries. However, it is important to compare survival in different series based on accurate prognostic data. The European Organisation for Research and Treatment of Cancer (EORTC) and the Cancer and Leukaemia Group B (CALGB) have recently published prognostic scoring systems. We have assessed the prognostic variables, validated the EORTC and CALGB prognostic groups, and evaluated survival in a series of 142 patients.

METHODS

Case notes of 142 consecutive patients presenting in Leicester since 1988 were reviewed. Univariate analysis of prognostic variables was performed using a Cox proportional hazards regression model. Statistically significant variables were analysed further in a forward, stepwise multivariate model. EORTC and CALGB prognostic groups were derived, Kaplan-Meier survival curves plotted, and survival rates were calculated from life tables.

RESULTS

Significant poor prognostic factors in univariate analysis included male sex, older age, weight loss, chest pain, poor performance status, low haemoglobin, leukocytosis, thrombocytosis, and non-epithelial cell type (p<0.05). The prognostic significance of cell type, haemoglobin, white cell count, performance status, and sex were retained in the multivariate model. Overall median survival was 5.9 (range 0-34.3) months. One and two year survival rates were 21.3% (95% CI 13.9 to 28.7) and 3. 5% (0 to 8.5), respectively. Median, one, and two year survival data within prognostic groups in Leicester were equivalent to the EORTC and CALGB series. Survival curves were successfully stratified by the prognostic groups.

CONCLUSIONS

This study validates the EORTC and CALGB prognostic scoring systems which should be used both in the assessment of survival data of series in different countries and in the stratification of patients into randomised clinical studies.

Developing genetic privacy legislation: the South Carolina experience

The availability of presymptomatic and predisposition genetic testing has spawned the need for legislation prohibiting health insurance discrimination on the basis of genetic information. The federal effort, the Health Insurance Portability and Accountability Act (HIPAA) of 1996, falls short by protecting only those who access insurance through group plans. A committee of University of South Carolina professionals convened in 1996 to develop legislation in support of genetic privacy for the state of South Carolina. The legislation prevents health insurance companies from denying coverage or setting insurance rates on the basis of genetic information. It also protects the privacy of genetic information and prohibits performance of genetic tests without specific informed consent. In preparing the bill, genetic privacy laws from other states were reviewed, and a modified version of the Virginia law adopted. The South Carolina Committee for the Protection of Genetic Privacy version went a step further by including enforcement language and excluding Virginia's sunset clause. The definition of genetic information encompassed genetic test results, and importantly, includes family history of genetic disease. Our experience in navigating through the state legislature and working through opposition from the health insurance lobby is detailed herein.

Reduced subendocardial ryanodine receptors and consequent effects on cardiac function in conscious dogs with left ventricular hypertrophy

The goal of this study was to examine the transmural distribution of ryanodine receptors in left ventricular (LV) hypertrophy (LVH) and its in vivo consequences. Dogs were chronically instrumented with an LV pressure gauge, ultrasonic crystals for measurement of LV internal diameter and wall thickness, and a left circumflex coronary blood flow velocity transducer. Severe LVH was induced by chronic banding of the aorta (12+/-1 months), which resulted in a 78% increase in LV/body weight. When ryanodine was infused directly into the circumflex coronary artery, it did not affect LV global function or systemic hemodynamics; however, it reduced LV wall thickening and delayed relaxation in the posterior wall in control dogs but was relatively ineffective in dogs with LVH. In LV sarcolemmal preparations, [3H]ryanodine ligand binding revealed a subendocardial/subepicardial gradient in normal dogs. In LVH there was a 45% decrease in ryanodine receptor binding and a loss in the natural subendocardial/subepicardial gradient, which roughly correlated inversely with the extent of LVH and directly with regional wall motion. Both mRNA and Western analyses revealed similar findings, with a reduction of the transmural mRNA levels and a loss in the natural gradient between subendocardial and subepicardial layers in LVH. Thus, ryanodine receptor message and binding in LVH is reduced preferentially in the subendocardium with consequent attenuation of the action of ryanodine in vivo. The selectively altered ryanodine regulation subendocardially in LVH could reconcile some of the controversy in this field and may play a role in mediating decompensation from stable LVH.

A physiological comparison of flutter valve drainage bags and underwater seal systems for postoperative air leaks

BACKGROUND

A study was undertaken to compare the relative physiological effects of underwater seal (UWS) versus flutter valve (FV) pleural drainage systems in the treatment of postoperative air leaks.

METHOD

Fourteen patients with air leaks of 1-11 days duration, following lobectomy (n = 5), bullectomy (n = 4), decortication (n = 4), and pleural biopsy (n = 1) were analysed. Intrapleural pressure (IPP) measurements were made using an in-line external strain gauge connected directly to the intercostal tube. Patients were connected simultaneously to both UWS and FV drainage systems and pressures were measured sequentially, isolating each system in turn. Maximum (IPPmax) and minimum (IPPmin) intrapleural pressures were calculated from graphic traces. The degree of lung expansion was recorded by chest radiography.

RESULTS

At resting tidal volume IPPmax was significantly higher with the UWS system (mean difference 0.8 mm Hg, 95% CI 0 to 1.6, p = 0.046) and IPPmin was significantly lower with the FV system (1.8 mm Hg, 95% CI 0.3 to 3.3, p = 0.023). The lung was fully expanded in 50% of patients at the time of study. The mean difference in IPPmin between systems was significantly increased when the lung was fully expanded (mean 2.8 mm Hg, 95% CI 0.1 to 5.5, p = 0.042). The mean difference in IPPmax was not affected by the degree of lung expansion (0.79, 95% CI -0.83 to 2.4, p = 0.31).

CONCLUSION

The results of this study suggest that, when postoperative air leak exists without a persistent pleural space, the flutter valve may provide a physiologically more effective alternative to the underwater seal drainage system.

Systematic review and guide to selection of selective serotonin reuptake inhibitors

A meta-analysis of 20 short term comparative studies of 5 selective serotonin reuptake inhibitors (SSRIs; citalopram, fluoxetine, fluvoxamine, paroxetine and sertraline) has shown no difference in efficacy between individual compounds but a slower onset of action of fluoxetine. There were suggestions that fluoxetine caused more agitation, weight loss and dermatological reactions than the other SSRIs. More patients discontinued fluvoxamine and fewer patients stopped sertraline because of adverse effects than their comparator SSRIs. The most common adverse reactions to the SSRIs were gastrointestinal (especially nausea) and neuropsychiatric (particularly headache and tremor). Data from the Committee on Safety of Medicines showed more reports of suspected reactions (including discontinuation reactions) to paroxetine, and of gastrointestinal reactions to fluvoxamine and paroxetine, than the other SSRIs during their first 2 years of marketing. Prescription-event monitoring revealed a higher incidence of adverse events related to fluvoxamine than its comparators. There were higher incidences of gastrointestinal symptoms, malaise, sedation and tremor during treatment with fluvoxamine and of sedation, tremor, sweating, sexual dysfunction and discontinuation reactions with paroxetine. Fluoxetine was not associated with a higher incidence of suicidal, aggressive and related events than the other SSRIs. Patients have survived large overdoses of each of the compounds, but concern has been expressed over 6 fatalities following overdoses of citalopram. Drug interactions mediated by cytochrome P450 enzymes are theoretically less likely to occur during treatment with citalopram and sertraline, but there is a sparsity of clinical data to support this. Methodological difficulties and price changes do not allow choice for recommendations on the choice of SSRI based on pharmacoeconomic data. Taking into account the strengths and weaknesses of the methods used to compare drugs, guidelines to the selection of individual SSRIs in clinical practice are proposed. Citalopram should be avoided in patients likely to take overdoses. Fluoxetine may not be the drug of first choice for patients in whom a rapid antidepressant effect is important or for those who are agitated, but it may have advantages over other SSRIs in patients who are poorly compliant with treatment and those who have previously had troublesome discontinuation symptoms. Fluvoxamine, and possibly paroxetine, should not be used as first choice in patients especially prone to SSRI-related adverse reactions, while paroxetine should be avoided if previous discontinuation of treatment was troublesome. When in doubt about the risks of drug interactions, citalopram or sertraline should be considered given the lower theoretical risk of interactions.

Basic principles of cancer genetics

All cancer can be described as genetic, that is, due to altered DNA. Many of these mutations will be accumulated during the normal division of cells. However, some people may inherit abnormal genes, which predispose those individuals to high risk of certain malignancies. These individuals can sometimes be identified as having a family history of affected individuals, some of which might have early age of onset or multiple malignancies. Specific genes have been identified as being associated with certain of these malignancies. The hereditary cancers include (but are not limited to) ovary, breast, colon, endometrium, and to a lesser extent, prostate, skin and pancreas. Some of these cancer predisposing genes are highly penetrant with up to 80 to 90 percent of gene carriers developing the associated malignancy within a 70 year life expectancy. Molecular testing for the presence of cancer predisposing genes is available for many of the hereditary syndromes. While there currently is no way to correct a mutant gene, early detection and some techniques of chemoprevention are of clinical value. People who fear that they are at high risk only learn that they are not, can benefit from the relief of anxiety through the genetic counseling process.

Downregulation of caveolin by chronic beta-adrenergic receptor stimulation in mice

Caveolae, flask-shaped invaginations of cell membranes, are believed to play pivotal roles in transmembrane transportation of molecules and cellular signaling. Caveolin, a structural component of caveolae, interacts directly with G proteins and regulates their function. We investigated the effect of chronic beta-adrenergic receptor stimulation on the expression of caveolin subtypes in mouse hearts by immunoblotting and Northern blotting. Caveolin-1 and -3 were abundantly expressed in the heart and skeletal muscles, but not in the brain. Continuous (-)-isoproterenol, but not (+)-isoproterenol, infusion via osmotic minipump (30 micrograms.g-1.day-1) for 13 days significantly downregulated both caveolin subtypes in the heart. The expression of caveolin-1 was reduced by 48 +/- 6.1% and that of caveolin-3 by 28 +/- 4.0% (P < 0.01, n = 8 for each). The subcellular distribution of caveolin subtypes in ventricular myocardium was not altered as determined by sucrose gradient fractionation. In contrast, the expression of both caveolin subtypes in skeletal muscles was not significantly changed. Our data suggest that the expression of caveolin subtypes is regulated by beta-adrenergic receptor stimulation in the heart.

Microvilli elongate in response to hydrogen peroxide and to perturbations of intracellular calcium

Using scanning electron microscopy and fluorescence microscopy, we have found that apical microvilli of diverse cell types, including nonepithelial cells, elongate in culture in response to the oxidative stress of hydrogen peroxide. The microvilli induced in culture on retinal pigment epithelial cells display a 30-nm axial periodicity similar to that described for stable microvilli of intestinal brush border. Microvilli can also be induced to elongate by chelating intracellular Ca2+ and by the Ca(2+)-uptake inhibitor thapsigargin. Thus a response of microvillar protrusion occurs widely and may be related to depletion of intracellular calcium stores.

Identification of a cis-acting regulatory element conferring inducibility of the atrial natriuretic factor gene in acute pressure overload

To identify the cis-acting regulatory element(s) which control the induction of the atrial natriuretic factor (ANF) gene in acute pressure overload, DNA constructs consisting of promoter elements linked to a reporter gene were injected into the myocardium of dogs, which underwent aortic banding or were sham-operated. Expression of a reporter gene construct harboring the ANF promoter (-3400ANF) was induced 6-12-fold after 7 d of pressure overload. An internal deletion of 556 bp (nucleotide sequence -693 to -137) completely abrogated the inducibility of the ANF reporter gene construct. An activator protein-1 (AP1)-like site (-496 to -489) and a cAMP regulatory element (CRE) (-602 to -596) are located within the deleted sequence. Site-directed mutagenesis of the AP1-like site but not the CRE completely prevented the induction of this construct to acute pressure overload. Further, the AP1-like site was able to confer inducibility of a heterologous promoter (beta-myosin heavy chain) to higher values than controls. Gel mobility shift assay (GMSA) supershift analysis was performed using a radiolabeled probe of the ANF promoter (-506/-483) that included the AP1-like site (ATGAATCA) sequence, as well as a probe converted to contain an AP1 consensus sequence (ATGACTCA). GMSA analysis demonstrated that the ANF AP1-like element could bind both a constitutively expressed factor and the AP1 proteins, and conversion to a true AP1 site increased its affinity for AP1. However, 7 d after the onset of pressure overload, the AP1 proteins were present only at low levels, and the major complex formed by the ANF AP1-like probe was not supershifted by a jun antibody. Using a large animal model of pressure overload, we have demonstrated that a unique cis-acting element was primarily responsible for the overload induction of the ANF gene.

Hartman interferometer: versatile integrated optic sensor for label-free, real-time quantification of nucleic acids, proteins, and pathogens

The Hartman interferometer, a proprietary integrated optic sensor, provides a basis for a broad range of biomedical diagnostics, including antibody-based and gene probe-based assays. As with other evanescent-wave optical sensors, the interferometer measures the refractive index change resulting from biomolecular binding on a waveguide surface. The exciting promise of evanescent-wave sensors lies, in general, in their potential to be used as label-free, real-time transducers that can operate in a true mix-and-read fashion and provide fast, quantitative results. One of the major issues facing their development, however, is creating a simple, low-cost configuration for multianalyte testing. The Hartman interferometer addresses this challenge by relying on linearly polarized light and a planar waveguide format, thereby avoiding the problems associated with circular polarization and channel waveguides. We report preliminary experiments that demonstrate the applicability of this sensor configuration to detection of a wide range of protein, nucleic acid, and pathogen analytes.

Video-assisted thoracoscopy in the evaluation of penetrating thoracic trauma

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Divergence of beta-myosin heavy chain (betaMHC) expression in fetal rat cardiomyocytes in vitro and adult rat heart in vivo

The myosin heavy chain gene products are an important determinant of myocardial functional properties. Although a strong positive element (beta f1) within the betaMHC promoter region has previously been identified, to date no species comparisons in promoter strength have been made. To examine this question, we have used betaMHC deletion constructs, containing the rat or human beta f1 enhancer region, to determine expression both in vitro using rat fetal cardiomyocytes and in vivo by direct injection into adult rat heart. When reporter constructs were transfected into cultured fetal rat cardiomyocytes, the human beta reporter was expressed more than 3 fold above the equivalent rat construct. Exchange of the beta f1 enhancer indicated that the human sequence of the beta f1 enhancer was largely responsible. However, these findings were not replicated when the reporters were injected into the adult rat heart. In the adult myocardium the levels of reporter expression were similar for the betaMHC promoter reporters studied. These findings demonstrate a divergence between primary cardiomyocytes maintained in culture and the cardiomyocytes found within the intact adult heart.

Double-blind comparative study of the antidepressant, unwanted and cardiac effects of minaprine and amitriptyline

1. A double-blind, multicentre study comparing the efficacy and safety of minaprine and amitriptyline in patients with major depression was carried out. Five hundred and thirty-one patients were randomly assigned to treatment with either minaprine 100 mg, 200 mg or 300 mg day-1 or with amitriptyline 150 mg day-1 (75 mg during the first week). The medication was administered for 6 weeks. 2. Efficacy was assessed using the Hamilton rating scale for depression (HDRS), the Montgomery-Asberg depression rating scale (MADRS) and visual analogue assessments of depression carried out by both the investigators and patients. Unwanted effects were assessed by a questionnaire and spontaneous reporting. In a subgroup of patients cardiovascular effects were investigated by high speed ECG and systolic time intervals. 3. Patients in each treatment group showed a significant clinical improvement (P < 0.01) from baseline. The mean HDRS and MADRS scores adjusted for baseline differences, showed significantly less improvement in the minaprine 100 mg once daily (P < 0.01) and the minaprine 300 mg daily (P < 0.01) groups than in the amitriptyline group at both week 4 and week 6. The MADRS score at week 4 suggested that 200 mg day-1 minaprine was less effective than amitriptyline (P < 0.05), but there was no difference between the two groups at week 6 on either the HDRS or the MADRS. 4. Both drugs were well tolerated and there were no significant differences between treatment groups in any of the safety and tolerance assessments. In the ECG, amitriptyline produced a significant increase in the heart rate and PR interval while minaprine had no effect on electrocardiographic measurements. Neither drug produced changes in the systolic time intervals.

Cardiomyopathy in transgenic myf5 mice

To explore the compatibility of skeletal and cardiac programs of gene expression, transgenic mice that express a skeletal muscle myogenic regulator, bmyf5, in the heart were analyzed. These mice develop a severe cardiomyopathy and exhibit a significantly shorter life span than do their nontransgenic littermates. The transgene was expressed from day 7.5 post coitum forward, resulting in activation of skeletal muscle genes not normally seen in the myocardium. Cardiac pathology was not apparent at midgestation but was evident by day 2 of postnatal life, and by 42 days, hearts exhibited multifocal interstitial inflammation, fibrosis, cellular hypertrophy, and occasional myocyte degeneration. All four chambers of the heart were enlarged to varying degrees, with the atria demonstrating the most significant hypertrophy (>100% in 42-day-old mice). The transgene and several skeletal muscle-specific genes were expressed only in patchy areas of the heart in heterozygous mice. However, molecular markers of hypertrophy (such as alpha-skeletal actin and atrial myosin light chain- 1) were expressed with a wider distribution, suggesting that their induction was secondary to the expression of the transgene, In older (28-week-old) mice, lung weights were also significantly increased, consistent with congestive heart failure. The life span of bmyf5 mice was significantly shortened, with an average life span of 109 days, compared with at least a twofold longer life expectancy for nontransgenic littermates. Expression of the transgene was associated with an increase in Ca2+-stimulated myofibrillar ATPase in myofibrils obtained from the left ventricles of 42-day-old bmyf5 mice. Myocardial bmyf5 expression therefore induces a program of skeletal muscle gene expression that results in progressive cardiomyopathy that may be due to incompatibility of heart and skeletal muscle structural proteins.

Echocardiographic assessment of left ventricular mass and systolic function in mice

The increasing use of transgenic mouse models for investigating the mechanisms of cardiac growth and function has made it important to develop noninvasive methods for assessing murine cardiac anatomy, size, and function. At present, murine cardiac mass can be determined only at necropsy. Left ventricular (LV) function can be assessed by use of various catheterization techniques, but these approaches are usually terminal procedures and provide no information about chamber anatomy and dimensions. Although transthoracic echocardiography has been used to study the LVs of rats and larger animals, the considerably smaller LV masses and somewhat faster heart rates of mice pose significant challenges to obtaining good-quality echocardiograms. In this study we tested the hypothesis that transthoracic echocardiography can image the murine LV as well as provide assessments of LV mass and function. Our results in a series of 33 mice, including normal, transgenic, and aortic-banded subgroups, demonstrate the capability of transthoracic two-dimensionally directed M-mode echocardiography in mice to (1) obtain good-quality images, (2) produce estimates of LV mass having good correlations with directly determined LV mass in normal mice, (3) detect LV hypertrophy noninvasively in different experimental models, and (4) identify impaired LV systolic function. Thus, echocardiography appears to be a promising approach for noninvasively assessing LV mass and function in mice.