Perioperative or only adjuvant gemcitabine plus nab-paclitaxel for resectable pancreatic cancer (NEONAX)-a randomized phase II trial of the AIO pancreatic cancer group.

BACKGROUND: Data on perioperative chemotherapy in resectable pancreatic ductal adenocarcinoma (rPDAC) are limited. NEONAX examined perioperative or adjuvant chemotherapy with gemcitabine plus nab-paclitaxel in rPDAC (National Comprehensive Cancer Network criteria). PATIENTS AND METHODS: NEONAX is a prospective, randomized phase II trial with two independent experimental arms. One hundred twenty-seven rPDAC patients in 22 German centers were randomized 1 : 1 to perioperative (two pre-operative and four post-operative cycles, arm A) or adjuvant (six cycles, arm B) gemcitabine (1000 mg/m2) and nab-paclitaxel (125 mg/m2) on days 1, 8 and 15 of a 28-day cycle. RESULTS: The primary endpoint was disease-free survival (DFS) at 18 months in the modified intention-to-treat (ITT) population [R0/R1-resected patients who started neoadjuvant chemotherapy (CTX) (A) or adjuvant CTX (B)]. The pre-defined DFS rate of 55% at 18 months was not reached in both arms [A: 33.3% (95% confidence interval [CI] 18.5% to 48.1%), B: 41.4% (95% CI 20.7% to 62.0%)]. Ninety percent of patients in arm A completed neoadjuvant treatment, and 42% of patients in arm B started adjuvant chemotherapy. R0 resection rate was 88% (arm A) and 67% (arm B), respectively. Median overall survival (mOS) (ITT population) as a secondary endpoint was 25.5 months (95% CI 19.7-29.7 months) in arm A and 16.7 months (95% CI 11.6-22.2 months) in the upfront surgery arm. This difference corresponds to a median DFS (mDFS) (ITT) of 11.5 months (95% CI 8.8-14.5 months) in arm A and 5.9 months (95% CI 3.6-11.5 months) in arm B. Treatment was safe and well tolerable in both arms. CONCLUSIONS: The primary endpoint, DFS rate of 55% at 18 months (mITT population), was not reached in either arm of the trial and numerically favored the upfront surgery arm B. mOS (ITT population), a secondary endpoint, numerically favored the neoadjuvant arm A [25.5 months (95% CI 19.7-29.7months); arm B 16.7 months (95% CI 11.6-22.2 months)]. There was a difference in chemotherapy exposure with 90% of patients in arm A completing pre-operative chemotherapy and 58% of patients starting adjuvant chemotherapy in arm B. Neoadjuvant/perioperative treatment is a novel option for patients with resectable PDAC. However, the optimal treatment regimen has yet to be defined. The trial is registered with ClinicalTrials.gov (NCT02047513) and the European Clinical Trials Database (EudraCT 2013-005559-34).

Surgical technique for placement of the automated low flow ascites pump (Alfapump).

Approximately 10% of patients with ascites associated with cirrhosis fail to respond to dietary rules and diuretic treatment and therefore present with refractory ascites. In order to avoid iterative large-volume paracentesis in patients with contraindication to TIPS, the automated low flow ascites pump system (Alfapump) was developed to pump ascites from the peritoneal cavity into the urinary bladder, where it is eliminated spontaneously by normal micturition. This manuscript reports the surgical technique for placement of the Alfapump.

Clinical spectrum and outcomes of patients with encephalitis requiring intensive care.

BACKGROUND AND PURPOSE: Our aim was to characterize the clinical profile, temporal changes and outcomes of patients with severe encephalitis. METHODS: A retrospective cohort study was conducted on adult patients with encephalitis admitted to the medical intensive care unit (ICU) of a university hospital over a 20-year period. Patients' characteristics and outcomes were compared between two 10-year periods: (i) 1991-2001 and (ii) 2002-2012. Multivariate logistic regression was used to analyze factors associated with a poor outcome, as defined by a modified Rankin scale (mRS) score of 4-6 (severe disability or death) 90 days after admission. RESULTS: A total of 279 patients were studied. Causes of encephalitis were infections (n = 149, 53%), immune-mediated causes (n = 41, 15%) and undetermined causes (n = 89, 32%). The distribution of causes differed significantly between the two periods, with an increase in the proportion of encephalitis recognized to be of immune-mediated causes. At day 90, 208 (75%) patients had an mRS = 0-3 and 71 (25%) had an mRS = 4-6. After adjustment for functional status before admission, the following parameters were independently associated with a poor outcome: coma [odds ratio (OR) 7.09, 95% confidence interval (95% CI) 3.06-17.03], aspiration pneumonia (OR 4.02, 95% CI 1.47-11.03), a lower body temperature (per 1 degree, OR 0.72, 95% CI 0.53-0.97), elevated cerebrospinal fluid protein levels (per 1 g/l, OR 1.55, 95% CI 1.17-2.11) and delayed ICU admission (per 1 day, OR 1.04, 95% CI 1.01-1.07). CONCLUSIONS: Indicators of outcome in adult patients with severe encephalitis reflect both the severity of illness and systemic complications. Our data suggest that patients with acute encephalitis may benefit from early ICU admission.

Infective endocarditis with symptomatic cerebral complications: contribution of cerebral magnetic resonance imaging.

BACKGROUND: Cerebral complications are well-identified causes of morbidity and mortality in patients with infective endocarditis (IE). Few studies have analysed the impact of brain magnetic resonance imaging (MRI) in IE patients with neurological manifestations. OBJECTIVES: The aims of this study were to assess the MRI contribution to the management of patients with IE neurological manifestations and to compare cerebral CT and MRI findings. MATERIAL AND METHODS: Patients with definite or probable IE and neurological manifestations were prospectively enrolled from 2005 to 2008, in a university hospital (Bichat Claude Bernard Hospital, Paris). Clinical and radiological characteristics and echocardiographic findings were systematically recorded. Brain MRI with angiography was performed and compared to available CT scans. The contribution of MRI results to cerebral involvement staging and to therapeutic plans was evaluated. RESULTS: Thirty patients, 37-89 years old, were included. Nineteen suffered from pre-existing heart disease. Blood cultures were positive in 29 cases and the main micro-organisms were streptococci (n = 14) and staphylococci (n = 13). The IE was mainly located on mitral (n = 15) and aortic valves (n = 13). Neurological events were strokes (n = 12), meningitis (n = 5), seizures (n = 1), impaired consciousness (n = 11) and severe headache (n = 1). MRI findings included ischaemic lesions (n = 25), haemorrhagic lesions (n = 2), subarachnoid haemorrhage (n = 5), brain abscess (n = 6), mycotic aneurysm (n = 7), vascular occlusion (n = 3) and cerebral microbleeds (n = 17). In 19/30 cases, neurological manifestations were observed before the diagnosis of IE. MRI was more sensitive than CT scan in detecting both clinically symptomatic cerebral lesions (100 and 81%, respectively) and additional asymptomatic lesions (50 and 23%, respectively). Therapeutic plans were modified according to MRI results in 27% of patients: antibiotherapy regimen modifications in 7% (switch for molecules with high cerebral diffusion) and surgical plan modifications in 20% (indication of valvular replacement due to the embolic nature of the vegetations revealed by MRI or postponement of surgery due to haemorrhagic lesions). None of the 16/30 (51%) operated-on patients experienced postoperative neurological worsening. In-hospital death occurred in 4 patients. CONCLUSION: In patients with IE neurological manifestations, MRI revealed a broader involvement of the brain (type and number of lesions) than indicated by clinical signs and/or CT scan. With a better disease staging of neurological manifestations, MRI brain imaging may help in patient management and the decision-making process especially for cardiac surgery indication and timing of valve replacement.

Cardiac specific effects of thyroid hormone analogues.

There is significant interest in development of thyroid hormone analogues to harness specific properties as therapeutic agents for a variety of clinical indications including obesity, hypercholesterolemia, heart failure, and thyrotoxicosis. To date, most analogues have been designed to target liver specific effects, which can promote weight loss and lipid lowering through either tissue specific uptake or thyroid hormone receptor (TR) ß isoform selectivity at the same time minimizing the unwanted cardiac and bone effects. We have developed a molecular biomarker assay to study the induction of the transcription of the cardiac specific α-myosin heavy chain (MHC) gene as a more sensitive and specific measure of thyroid hormone action on cardiac myocytes. We tested 5 TRß and 1 TRα selective agonists as well as 2 putative TR antagonists in our α-MHC hnRNA assay. Using reverse transcription and polymerase chain reaction, we measured the induction of the α-MHC primary transcript in response to administration of drug. The TRα and only 2 of the TRß agonists were highly active, when compared to the effect of T3, at the level of the cardiac myocyte. In addition, our data suggests that the reason that the antagonist NH-3 is not able to block the T3-mediated induction of α-MHC is that it does not get transported into the cardiac myocyte. Our data suggest that this assay will be useful in preclinical studies of the potential cardiac specific effects of thyroid hormone analogues and that predictions of function based on structure are not necessarily accurate or complete.

Hypoplasia or stenosis: Usefulness of high-resolution MRI.

INTRODUCTION: Hypoplastic basilar (BA) and vertebral arteries (VA) can cause posterior circulation infarctions. Distinction between hypoplastic and atherosclerotic BA can be difficult with usual angiographic methods (MR, CT or conventional angiographies), only showing arterial luminogram. High-resolution MRI (HRMRI) of the arterial wall is promising in identifying intracranial artery plaques. OBSERVATION: A 70-year-old man with vascular risk factors suddenly presented with vertigo. MRI showed no brain infarction. Contrast-enhanced MRA showed small and irregular BA lumen compatible with severe atherosclerotic stenosis. An associated persistent primitive trigeminal artery was noticed. HRMRI of the BA rectified the initial angiographic diagnosis by showing a normal vessel wall without any thickening that could suggest atherosclerotic plaque. CONCLUSION: In the event of BA lumen narrowing, HRMRI may help distinguish between hypoplastic and atherosclerotic artery.

Blended cognitive behaviour therapy for children and adolescents with mitochondrial disease targeting fatigue (PowerMe): study protocol for a multiple baseline single case experiment.

BACKGROUND: Mitochondrial disease is a rare, hereditary disease with a heterogeneous clinical presentation. However, fatigue is a common and burdensome complaint in children and adolescents with mitochondrial disease. No psychological intervention targeting fatigue exists for paediatric patients with a mitochondrial disease. We designed the PowerMe intervention, a blended cognitive behaviour therapy targeting fatigue in children and adolescents with mitochondrial disease. The aim of the intervention is to reduce perceived fatigue by targeting fatigue-related cognitions and behaviours. METHODS: A multiple baseline single case experiment will be conducted in five children (8-12 years old) and 5 adolescents (12-18 years old) with mitochondrial disease and severe fatigue. Patients will be included in the study for 33 weeks, answering weekly questions about the fatigue. Patients will be randomly assigned a baseline period of 5 to 9 weeks before starting the PowerMe intervention. The intervention consists of face-to-face and online sessions with a therapist and a website with information and assignments. The treatment will be tailored to the individual. Each patient will work on their personalized treatment plan focusing on personally relevant goals. The primary outcome is perceived fatigue. Secondary outcomes are quality of life, school presence and physical functioning. DISCUSSION: The results of the PowerMe study will provide information on the efficacy of a blended cognitive behaviour therapy on reducing perceived fatigue and its impact on daily life in children and adolescents with mitochondrial disease. Strengths and limitations of the study design are discussed. TRIAL REGISTRATION: Dutch Trial Register NTR 7675. Registered on 17 December 2018. Identifier https://www.trialregister.nl/trial/7433.

Molecular cytogenetic characterization of the human cerebral microvessel endothelial cell line hCMEC/D3.

The immortalized human cerebral microvessel endothelial cell line hCMEC/D3 has been repeatedly used as a model of human blood-brain barrier (BBB). hCMEC/D3 cells between passage 25 and 35 are most often applied in research, remained phenotypically nontransformed, and cells maintained many characteristics of human brain endothelial cells. Also hCMEC/D3 was thought to have conserved a normal diploid karyotype over all these passages. Here we characterized the cell line using high-resolution multicolor fluorescence in situ hybridization (FISH) approaches and revealed a complex karyotype in the 30th passage. Clonal cryptic unbalanced structural rearrangements and numerical aberrations were discovered and described as follows: 45 approximately 48,XX, -X,del(5)(q11)[2],del(9)(q11)[3],+9[3],del(11)(q13 approximately 14)[2], der(14)t(14;21)(q32.33;q22.3)[28],der(15)t(9;15)(p11;p11)[13], dup(15)(p11q11)[5],der(21)t(17;21)(p12;q22)[9],-22[6][cp28]. In summary, a complex karyotype with clonal unbalanced chromosomal rearrangements is present in hCMEC/D3. Thus, we solicit to include molecular cytogenetics in the testing of all cell lines prior to application of their use in complex studies.

Aseptic meningitis and ischaemic stroke in Fabry disease.

BACKGROUND: Fabry disease (OMIM 301 500) is an X-linked lysosomal storage disease. Neurological symptoms in Fabry disease mainly include stroke, acroparesthesia, cranial nerve palsies and autonomic dysfunction. We report on aseptic meningitis in Fabry patients. METHODS: Clinical analysis, brain magnetic resonance imaging, cerebrospinal fluid analysis, treatment and outcome data were analysed in three cases of meningitis associated with Fabry disease. FINDINGS: Mean age at meningitis onset was 26.6 (24-28) years. Headache was present in all cases and fever in two cases. Meningitis was always diagnosed before Fabry disease. A familial history of Fabry disease was present in two cases. Non-neurological symptoms caused by Fabry disease were present in all cases. All patients also suffered stroke and sensorineural hearing loss. Cerebrospinal fluid (CSF) analysis showed pleocytosis (mean, 36; range: 8-76 cells/mm(3)) and a high protein level (mean, 63; range, 47-70 mg/dl). C-reactive protein blood levels and erythrocyte sedimentation rate were raised. Diagnosis was assessed by low alpha-galactosidase A dosage and/or gene mutation analysis in all cases. All patients were treated with enzyme replacement therapy (ERT). In two cases, lumbar puncture was repeatedly performed and there was no normalisation of CSF under ERT alone, at 9 and 24 months of follow-up, respectively. One patient who suffered intracranial hypertension was treated efficiently with steroids, associated with azathioprine. The fact that Fabry disease could be an auto-inflammatory disorder is discussed. INTERPRETATION: Fabry disease may cause aseptic meningitis.

[Cardiac diffusion MRI of recent and chronic myocardial infarction: preliminary results]. / IRM de diffusion cardiaque dans l'infarctus du myocarde récent et chronique: expérience préliminaire.

PURPOSE: To use diffusion weighted MR imaging (DWI), a technique routinely used in patients with stroke, for diagnosis of myocardial infarction (MI). MATERIALS AND METHODS: A breath hold ECG gated DWI sequence (b = 300 sec/mm2) was developped and applied to 7 patients with recent MI (3-15 days), 3 patients with chronic MI (> 6 months) and 4 patients with valvular heart disease without MI (control cases). DWI data were correlated to T2W, first pass perfusion and delayed enhancement data. RESULTS: In all patients with recent MI, DWI showed an area of increased signal with reduction of ADC relative to normal myocardium. Hyperintense lesion on DWI corresponded to areas of delayed enhancement. The diffusion images were normal in patients with chronic MI or no MI. CONCLUSION: Even though no animal model or other reference method is available, these preliminary results indicate that DWI could assist clinicians in detecting recent MI.

[Cardiac damage due to scorpion envenomation: case involving atrial flutter]. / Envenimation scorpionique avec atteinte cardiaque: à propos d'une observation de flutter atrial.

The purpose of this report is to describe a case of scorpion envenomation observed in northern Chad in a 24-year-old-man with no medical history. The victim rapidly developed supraventricular arrhythmia due to catecholaminergic storm induced by the neurotoxic activity of the venom. Cardiomyopathy that can lead to fatal acute heart failure is a risk after scorpion envenomation. Heart damage is observed in 1% of scorpion envenomation cases and can result from several mechanisms, i.e., adrenergic myocarditis (as in the patient herein), toxic myocarditis or myocardial ischemia. Few articles describing supraventricular arrhythmia following scorpion envenomation have been published. It is paroxystic and regresses spontaneously in case of transient catecholaminergic storm. Occurrence of atrial flutter, even if not associated with heart failure, is an indication of severe scorpion envenomation and requires close patient monitoring and symptomatic treatment using betablocking drugs. The efficacy of specific treatment for scorpion envenomation, i.e., immunotherapy, remains controversial.

Progressive renal disease despite immunosuppressive therapy in a patient with Wegener s granulomatosis.

We present a patient with Morbus Wegener and crescentic glomerulonephritis. Treatment with cyclophosphamide and prednisolone resulted in the disappearance of signs and symptoms of systemic inflammation. However, renal function deteriorated. Renal biopsy showed evidence of continuing capillary necrosis. Renal function improved with added plasmapheresis treatment. This case report illustrates that in patients with vasculitis necrotizing glomerulonephritis may remain active despite immunosuppressive therapy, even in the absence of extrarenal disease activity.

[Acute stroke imaging before IV thrombolysis: what modality of imaging for France in 2007?]. / Thrombolyse IV et ischémie cérébrale: quelle imagerie en France en 2007?

PURPOSE: To report the results of a radiological survey of the management of acute stroke prior to intravenous thrombolysis. MATERIAL AND METHODS: A questionnaire on imaging as used in the management of stroke was sent to 80 stroke units across France at the beginning of 2007 and included the first imaging modality used (CT or MRI), the imaging protocol before treatment and the exclusion criteria followed for thrombolysis. RESULTS: CT was most often used as the first modality for the management of acute stroke (by 70% of the 53 responding centers) and 26 centers (49%) used both CT and MRI. Only 12 centers (22%) routinely performed MRI to screen for acute stroke. However, more than half the patients who had received thrombolysis in 2006 had been examined using MRI. In fact, after three-hour poststroke, intravenous thrombolysis was predominantly decided upon from MRI data. The survey showed that imaging criteria are well standardized for CT, whereas they are more variable for MRI. Furthermore, the majority (28 of 38) of the centers considered that thrombolysis could be applied despite a clinical contraindication (such as unknown time of onset or convulsions) if MRI categorically diagnosed an acute stroke. CONCLUSION: This survey showed that CT-based screening of acute stroke before thrombolysis remains the standard modality in France, with a consensus on decision-making criteria. The survey also revealed a change in imaging management, with a growing role for MRI as the first examination.

Randomized clinical trial comparing liver resection with and without perioperative assessment of liver function.

BACKGROUND: Liver function tests may help to predict outcomes after liver surgery. The aim of this study was to evaluate the clinical impact on postoperative outcome and patient management of perioperative liver function testing using the LiMAx® test. METHODS: A multicentre RCT was conducted in six academic liver centres. Patients with intrahepatic tumours scheduled for open liver resection of at least one segment were eligible. Patients were randomized to undergo additional perioperative liver function tests (LiMAx® group) or standard care (control group). Patients in the intervention arm received two perioperative LiMAx® tests, one before the operation for surgical planning and another after surgery for postoperative management. The primary endpoint was the proportion of patients transferred directly to a general ward. Secondary endpoints were severe complications, length of hospital stay (LOS) and length of intermediate care/ICU (LOI) stay. RESULTS: Some 148 patients were randomized. Thirty-six of 58 patients (62 per cent) in the LiMAx® group were transferred directly to a general ward, compared with one of 60 (2 per cent) in the control group (P < 0·001). The rate of severe complications was significantly lower in the LiMAx® group (14 per cent versus 28 per cent in the control group; P = 0·022). LOS and LOI were significantly shorter in the LiMAx® group (LOS: 10·6 versus 13·3 days respectively, P = 0·012; LOI: 0·8 versus 3·0 days, P < 0·001). CONCLUSION: Perioperative use of the LiMAx® test improves postoperative management and reduces the incidence of severe complications after liver surgery. Registration number: NCT01785082 ( https://clinicaltrials.gov).

Trifluoperazine inhibits the contraction of cultured rat cardiac cells and the phosphorylation of myosin light chain.

Cultured, spontaneously beating heart cells were used to study the role of calmodulin in regulating cardiac contraction. Trifluoperazine (TFP), an antipsychotic drug that binds to calmodulin, reversibly inhibited myocardial contraction. This effect occurred over a TFP concentration range of 5-100 muM with half maximal activity at approximately 15 muM TFP. When the phosphoprotein profile of TFP-treated cells was compared with control cultures, there was a significant decrease in (32)P content of the 20,000-D myosin light chain. As measured by two-dimensional gel electrophoresis, the fraction of phosphorylated myosin light chain decreased from 0.31+/-0.06 in control to 0.16+/-0.05 in TFP-treated cells (P < 0.05). This inhibition of protein phosphorylation was relatively selective, as two other phosphoproteins ( approximately 41,000 and 36,000 D) were unaffected, and a third protein ( approximately 28,000 D) showed an increase in (32)P activity. In contrast, the cessation of spontaneous beating by 50 mM KCl did not reproduce these changes. This inhibition of contraction mediated by TFP associated with alterations in the phosphorylation of certain cardiac phosphoproteins suggests a role for calmodulin and for the myosin light chain in the regulation of cardiac cell contraction.

Effects of thyroid hormone on cardiac size and myosin content of the heterotopically transplanted rat heart.

Infrarenal heterotopic cardiac isografts maintain structural and functional integrity. We have used this transplantation model to further explore the mechanisms of thyroid hormone-induced cardiac hypertrophy. Thyroid hormone administration, 1-thyroxine (T4) 10 micrograms/animal per d, led to a significant 30% increase in total heart weight and a 40% increase in the myosin content of the in situ heart when compared with control. In contrast, T4 treatment was without effect on the heart weight, protein content, rate of protein synthesis, or calculated myosin content of the heterotopic, nonworking heart. Heterotopic hearts demonstrated a significant decrease in the percentage of the V1 myosin isoenzyme from 95% to 61%. This shift occurred in euthyroid animals but was prevented by T4 treatment. These results suggest that thyroxine-induced cardiac hypertrophy is mediated indirectly via changes in cardiac work. Myosin isoenzyme expression can be altered by changes in work load but is still responsive to increased levels of thyroid hormone.

Activation of myocardial adenyl cyclase by histamine in guinea pig, cat, and human heart.

Histamine has positive inotropic and chronotropic effects on the heart which are not abolished by beta adrenergic-blocking agents. Since the positive inotropic and chronotropic effects of other hormones on the heart are thought to be mediated by cyclic 3',5'-AMP, we examined the effect of histamine on adenyl cyclase in particulate preparations of guinea pig, cat, and human myocardium. Histamine at the peak of its dose-response curve, 3 x 10(-4)moles/liter, produced approximately a 300% increase in cyclic 3',5'-AMP accumulation in the guinea pig, 60% in the cat, and 90% in the human heart particles. Half-maximal activity for the histamine mediated activation of adenyl cyclase in the guinea pig was 9 x 10(-6)moles/liter, almost identical with that observed for norepinephrine in the same preparation. DL-Propranolol, 1 x 10(-5)moles/liter, did not abolish the activation of adenyl cyclase produced by histamine but did abolish the activation produced by norepinephrine. In contrast, diphenhydramine hydrochloride, Benadryl, 8 x 10(-5)moles/liter, abolished the activation of adenyl cyclase by histamine but not that produced by norepinephrine. These data suggest that there are at least two receptor sites in guinea pig heart mediating the activation of adenyl cyclase, one responsive to histamine, the other to norepinephrine. In addition, combined maximal doses of histamine and norepinephrine produced completely additive effects on the activation of adenyl cyclase, which suggests that at least two separate adenyl cyclase systems are present in the heart, each responsive to one of these hormones. However, definitive proof would require physical separation of the two enzymes.

Solubilized myocardial adenylate cyclase. Restoration of histamine responsiveness by phosphatidylserine.

We have recently described the preparation of a solubilized cat myocardial adenylate cyclase which is unresponsive to histamine, norepinephrine, glucagon, and thyroxine, the hormones which activate the particulate enzyme. Since hormone receptors may consist of proteins and phospholipids, we determined the effect of several phospholipids on restoring the responsiveness of the solubilized adenylate cyclase to histamine. The addition of phosphatidylserine completely restored the histamine-mediated activation of the solubilized enzyme in contrast to phosphatidylethanolamine and phosphatidylinositol which were without effect. The concentration of histamine producing half-maximal activation of adenylate cyclase, 2 x 10(-5) M, was virtually identical with that observed in the particulate preparation. The antihistamine, diphenhydramine, 8 x 10(-5) M, abolished activation of adenylate cyclase by histamine in both the solubilized and particulate preparations. Phosphatidylserine also restored glucagon responsiveness, but did not restore norepinephrine responsiveness. It would appear that phosphatidylserine produced the necessary molecular configuration of the adenylate cyclase for histamine binding and activation of the enzyme.

Hemodynamic regulation of myosin heavy chain gene expression. Studies in the transplanted rat heart.

Cardiac work is a major determinant of heart size and growth. Heterotopic cardiac isografts are hemodynamically unloaded and undergo atrophy. To determine the molecular changes that occur as a result of hemodynamic unloading, we have studied the rate of synthesis of total cardiac proteins and myosin heavy chain (MHC) and the expression of the myosin heavy chain gene as reflected in the messenger RNA levels for alpha- and beta-MHC isoforms. 72 h after transplantation there is a significant decrease in left ventricular size accompanied by a 27% decrease in the rate of total cardiac protein synthesis and a 53% decrease in the rate of myosin heavy chain synthesis. In contrast to isografts 14 d after transplantation which have a decrease in protein synthetic capacity, simultaneous measurements of 18S ribosomal RNA and myosin messenger RNA suggest that after 3 d the decrease in synthesis is due to a change in the efficiency of protein translation. While the working in situ heart expresses primarily alpha-MHC mRNA (97%) hemodynamic unloading leads to a 43% decrease in alpha-MHC mRNA concentration and the de novo expression of the beta-MHC mRNA. Total MHC mRNA (alpha plus beta) concentration analyzed by a quantitative S1 nuclease protection assay was similar in the two groups of hearts. Thus, in association with hemodynamic unloading there are changes in cardiac myosin heavy chain content as a result of both gene transcription and protein translation mechanisms.