Klotho as an Early Marker of Acute Kidney Injury Following Cardiac Surgery: A Systematic Review

Acute kidney injury is a common complication following cardiac surgery (CSA-AKI). Serum creatinine levels require a minimum of 24-48 h to indicate renal injury. Nevertheless, early diagnosis remains critical for improving patient outcomes. A PRISMA-compliant systematic review of the PubMed and CENTRAL databases was performed to assess the role of Klotho as a predictive biomarker for CSA-AKI (end-of-search date: 17 February 2024). An evidence quality assessment of the four included studies was performed with the Newcastle-Ottawa scale. Among the 234 patients studied, 119 (50.8%) developed CSA-AKI postoperatively. Serum Klotho levels above 120 U/L immediately postoperatively correlated with an area under the curve (AUC) of 0.806 and 90% sensitivity. Additionally, a postoperative serum creatinine to Klotho ratio above 0.695 showed 94.7% sensitivity and 87.5% specificity, with an AUC of 92.4%, maintaining its prognostic validity for up to three days. Urinary Klotho immunoreactivity was better maintained in samples obtained via direct catheterization rather than indwelling catheter collection bags. Storage at -80 °C was necessary for delayed testing. Optimal timing for both serum and urine Klotho measurements was from the end of cardiopulmonary bypass to the time of the first ICU lab tests. In conclusion, Klotho could be a promising biomarker for the early diagnosis of CSA-AKI. Standardization of measurement protocols and larger studies are needed to validate these findings.

Complete resolution of paraneoplastic syndrome of inappropriate antidiuretic hormone secretion following thymic small-cell carcinoma thoracoscopic resection

Thymic neuroendocrine tumours are rare anterior mediastinal neoplasms often associated with paraneoplastic syndromes. A patient presented with intractable hyponatraemia and a DOTATATE-avid mediastinal mass. Following medical optimization, she underwent thoracoscopic thymectomy with en bloc thymic small-cell carcinoma resection. Her symptoms resolved and her sodium levels normalized. In localized disease, curative-intent, minimally invasive thymic neuroendocrine tumour resection is safe and effective following preoperative staging and paraneoplastic syndrome management.

Role of Multimodality Imaging and Preoperative Management in Intrapericardial Paragangliomas

Intrapericardial paragangliomas are rare, highly vascular tumors that frequently adhere to adjacent structures and blood vessels, making surgical resection challenging. In this case series, we discuss the role of multimodality imaging and preoperative embolization in the management of 3 patients presenting with intrapericardial paragangliomas. (Level of Difficulty: Advanced.)

Robotic Mitral Valve Repair: A Decade of Experience with Echocardiographic Follow-up

BACKGROUND

Surgical approaches for mitral valve (MV) disease have evolved with the aim of developing minimally invasive techniques. While the safety of robotic procedures has been documented, there are limited data on long-term echocardiographic follow-up. This review demonstrates outcomes of 11 years of robotic MV repair at a single, tertiary institution.

METHODS

From 2008 to 2019, 843 patients underwent robotic MV repair at our institution. Repeated measures generalized least squares (GLS) modelling was used to assess the echocardiographic changes over time.

RESULTS

The median age was 58 years (IQR 50.8, 65.5) (591 males, 70.1%). Mechanism of MR was posterior leaflet prolapse in 479 (56.8%), bileaflet prolapse in 325 (38.6%), and anterior leaflet prolapse in 36 (4.3%). There were 3 early deaths (0.4%) and 24 early reoperations (2.8%). Echocardiographic follow up demonstrated left ventricular end systolic and diastolic dimensions, left atrial volume index and pulmonary pressure all continuously improvement up to 2 years postoperatively. Ejection fraction immediately declined postoperatively but then gradually improved to near normal over 2 years. Survival and freedom from reoperation at 10 years were 93% and 92.6%, respectively. When surveyed after dismissal, 93.4% reported their activity level at or above their peers and 93.3% reported no activity limitation from cardiac symptoms.

CONCLUSIONS

Robotic MV repair is safe and effective with excellent long-term results, including echocardiographic parameters that demonstrated early improvement in cardiac chamber size and maintenance of postoperative cardiac function. Exceedingly low mortality rates and freedom from reoperation are comparable to those of the standard open repair.

Meckel's Enterolith Causing Small Bowel Obstruction: A Useful Solution to a Unique Problem

Meckel’s diverticulum (MD) is the most common congenital anomaly of the gastrointestinal tract. Its course is usually benign but may also result in complications requiring surgical intervention. A diverticulum may also permit the removal of intraluminal objects without bowel resection and anastomosis.

A woman in her 50s was found to have a mechanical small bowel obstruction secondary to an intraluminal mass within the terminal ileum. On exploration, an MD was encountered proximal to the mass. A diverticulectomy was performed after maneuvering the enterolith into the diverticulum.

Meckel’s diverticulum with an associated enterolith is a rare cause of small bowel obstruction. Historic imaging may show long-standing stones in the bowel lumen and provide a diagnostic clue. Diverticulectomy may be performed to reduce the risks of small bowel resection and anastomosis. This technique can be used for other intraluminal objects requiring removal in the presence of an MD.

The Man Behind the Clagett Procedure: Dr Oscar Theron "Jim" Clagett

Dr O.T. "Jim" Clagett was a pioneer in surgery of the great vessels and thorax. The procedure that bears his name for treatment of postpneumonectomy empyema was only one of his many innovations in aortic, lung, and esophageal surgery. He performed over 35,000 operations and trained over 115 residents during his tenure at Mayo Clinic. His distinguished career highlights include: helping develop the field of cardiothoracic surgery during its infancy, starting the Thoracic Surgery Residency Program at Mayo Clinic, serving in numerous institutional and national leadership roles, and countless awards.

Patients undergoing surgery for oligometastatic oesophageal cancer survive for more than 2 years: bootstrapping systematic review data

OBJECTIVES

Oesophageal cancer oligometastasis is a state of limited systemic disease characterized by ˂5 metastases. Without surgery average survival is 4–12 months. We sought to estimate patient prognosis following the surgical resection of oligometastatic disease from oesophageal cancer.

METHODS

Eligible studies were identified through systematic search of PubMed and the Cochrane Library (end-of-search date: 20 November 2019). We estimated cumulative 1-, 3- and 5-year, as well as overall survival using bootstrap methodology with 1 000 000 repetitions per outcome.

RESULTS

We investigated six studies involving 420 patients who underwent metastasectomy for oligometastasis from oesophageal cancer. Adenocarcinoma [77.3%; 95% confidence interval (CI) 62.8–87.3] was the most prevalent histological type followed by squamous cell carcinoma (22.7%; 95% CI 12.7–37.2). Metastatic lesions were typically synchronous (91.5%; 95% CI 87.5–94.1). Overall, 73.5% (95% CI 67.5–78.6) of the patients underwent resection of the primary and metastatic tumours synchronously. Neoadjuvant chemoradiotherapy was utilized in the majority of the patients (66.7%; 95% CI 49.5–80.3) followed by neoadjuvant chemotherapy (33.3%; 95% CI 19.6–50.5). The mean overall survival was 24.5 months (95% CI 14.4–34.6). One-year survival was 88.3% (95% CI 85.6–90.8). Three-year survival and 5-year survival were 36.3% (95% CI 15.3–7.3) and 23.8% (95% CI 12.0–35.7), respectively.

CONCLUSIONS

Patients undergoing surgical resection of oesophageal oligometastasis survive for more than 24 months. Therefore, loco-regional control of oligometastatic disease appears to improve survival by at least 100%.

Minimally Invasive Surgery vs Device Closure for Atrial Septal Defects: A Systematic Review and Meta-analysis

Device closure is the first-line treatment for most atrial septal defects (ASDs). Minimally invasive cardiac surgery (MICS) has been found safe and effective for ASD closure with comparable mortality/morbidity and superior cosmetic results compared to conventional median sternotomy. Our goal was to compare percutaneous versus MICS of ASDs. A systematic review was performed using PubMed and the Cochrane Library (end-of-search date on May 22, 2019). Meta-analyses were conducted using fixed and random effects models. In the present systematic review, we analyzed six studies including 1577 patients with ASDs who underwent either MICS (n = 642) or device closure (n = 935). Treatment efficacy was significantly higher in the MICS (99.8%; 95% CI 98.9-99.9) compared to the device closure group (97.3%; 95% CI 95.6-98.2), (OR 0.1; 95% CI 0.02-0.6). Surgical patients experienced significantly more complications (16.2%; 95% CI 13.0-19.9) compared to those that were treated with a percutaneous approach (7.1%; 95% CI 5.0-9.8), (OR 2.0; 95% CI 1.2-3.2). Surgery was associated with significantly longer length of hospital stay (5.6 ± 1.7 days) compared to device closure (1.3 ± 1.4 days), (OR 4.8; 95% CI 1.1-20.5). Residual shunts were more common with the transcatheter (3.9%; 95% CI 2.7-5.5) compared to the surgical approach (0.95%; 95% CI 0.3-2.4), (OR 0.1; 95% CI 0.06-0.5). There was no difference between the two techniques in terms of major bleeding, hematoma formation, transfusion requirements, cardiac tamponade, new-onset atrial fibrillation, permanent pacemaker placement, and reoperation rates. MICS for ASD is a safe procedure and compares favorably to transcatheter closure. Despite longer hospitalization requirements, the MICS approach is feasible irrespective of ASD anatomy and may lead to a more effective and durable repair.

One Hundred and Counting: Dr Dwight C. McGoon's Enduring Legacy

Dr Dwight C. McGoon, a prolific surgeon at the Mayo Clinic in Rochester, Minnesota, achieved an amazing feat during the early days of cardiac surgery. In 1965, he reported a series of 100 consecutive aortic valve replacements with no in-hospital mortality. As a pioneer in adult and congenital cardiac surgery, his other contributions included novel uses of left ventricular and biventricular extracardiac conduits and describing repairs for mitral regurgitation resulting from ruptured chordae, transposition of the great arteries, truncus arteriosus, pulmonary stenosis, and pulmonary atresia. More than 50 years later, Dr McGoon is still remembered for his technical prowess, innovation, mentorship, and humanism.

Laparoscopic celiac plexus ganglioneuroma resection: A video case report

BACKGROUND

Ganglioneuromas are mature, benign neurogenic tumors that arise from neural crest-derived cells. Given the rarity of these tumors and their often close proximity to major vessels, there is a paucity of reports in the literature of minimally invasive resections of ganglioneuromas near the celiac plexus. We report a case of laparoscopic resection of a retroperitoneal ganglioneuroma adhering to the portal vein and celiac axis.

CASE SUMMARY

A 27-year-old female was referred to our medical center with a symptomatic retroperitoneal mass. Using high quality preoperative imaging and biopsies, we confirmed the diagnosis of a 4 cm ganglioneuroma abutting the celiac axis, portal vein, and the caudate lobe of the liver. We elected for laparoscopic resection after careful preoperative planning and discussions with the patient. Laparoscopy enhanced visualization of the tumor and its relationships to surrounding vital structures for optimal dissection. Ultrasonic energy devices and adjusting liver retraction to allow for manipulation of the mass facilitated a safe and effective resection in a tight space. There were no operative complications and the patient was discharged home on postoperative day 1 with no residual symptoms upon follow-up. With sufficient experience in laparoscopic surgery and preoperative imaging and diagnostics, a minimally invasive approach for removing this celiac plexus ganglioneuroma was successful.

CONCLUSION

In carefully selected patients, laparoscopic ganglioneuroma resection is appropriate, reducing postoperative morbidity, hospital length of stay, and recovery time.

Early Outcomes of Cardiac Surgery in Patients with Noonan Syndrome

There is a paucity of cardiac surgery outcomes data for patients with Noonan syndrome (NS). Our objective was to evaluate early results in these patients. Between January 1999 and December 2015, 29 patients (18 males, 62%) with NS underwent cardiac surgery at our institution. Mean age was 23 ± 17.9 years; 12 (41%) were under 18 years of age. Fourteen patients (48%) had prior sternotomies. The primary operations for the main diagnosis were pulmonary valve/conduit replacement/repair (n = 14, 48%), septal myectomy for obstructive hypertrophic cardiomyopathy (n = 7, 24%), aortic valve replacement/repair (n = 4, 14%), atrial septal defect (ASD) repair (n = 2, 7%), and cardiac transplantation (n = 2, 7%). Concomitant procedures were performed in 24 patients (83%), most commonly right ventricular outflow tract reconstruction (n = 13, 45%), mitral valve repair/replacement (n = 7, 24%), and ASD repair (n = 6, 21%). Mean bypass and cross-clamp times were 88.8 ± 51 minutes and 54.7 ± 67 minutes, respectively. There was 1 early death (3%). Postoperative morbidity occurred in 18 patients (62%), most commonly arrhythmias (n = 14, 48%) or respiratory insufficiency/pneumonia (n = 6, 21%). There were 2 early reoperations and 4 early readmissions. Univariate factors associated with morbidity included male gender (P = 0.03) and longer cross-clamp time (P = 0.02). Median length of hospital stay was 6 days (interquartile range 5-10.5 days). Patients with NS frequently have multiple cardiac lesions requiring a broad spectrum of operations. Early mortality is low despite procedure complexity. Although early postoperative morbidity is common, patients overall do well with reasonable hospital lengths of stay. Additional studies are needed to evaluate long-term outcomes and quality of life.

Pediatric Cardiac Trauma in the United States: A Systematic Review

Literature discussing cardiac injuries in children is limited. Systematic search of PubMed identified 21 studies enrolling 1,062 pediatric patients who experienced cardiac trauma in the United States during the period 1961 to 2012. The predominant type of injury was blunt cardiac contusion affecting 59.7% (n = 634/1,062) of the study population. Motor vehicle crashes (53.5%, n = 391/731) were the leading cause of blunt cardiac trauma, while gunshot wounds (50%, n = 150/300) accounted for most penetrating injuries. Overall mortality rate was 35.2% (n = 374/1,062).

Preventing pediatric cardiothoracic trauma: Role of policy and legislation

Data from the last 50 years suggest that pediatric patients typically suffer cardiothoracic injuries following blunt traumatic force (70%) in the setting of either motor vehicle crashes (53.5%) or vehicle-pedestrian accidents (18.2%). Penetrating trauma accounts for 30% of pediatric cardiothoracic injuries, half of which are gunshot wounds. Graduated driver licensing programs, gun-control legislation, off-road vehicle regulation, initiatives such as “Prevent the Bleed”, as well as professional society recommendations are key in preventing pediatric cardiothoracic injuries.

Initial Field Test of a Cloud-Based Cardiac Auscultation System to Determine Murmur Etiology in Rural China

A system for collection, distribution, and long distant, asynchronous interpretation of cardiac auscultation has been developed and field-tested in rural China. We initiated a proof-of-concept test as a critical component of design of a system to allow rural physicians with little experience in evaluation of congenital heart disease (CHD) to obtain assistance in diagnosis and management of children with significant heart disease. The project tested the hypothesis that acceptable screening of heart murmurs could be accomplished using a digital stethoscope and internet cloud transmittal to deliver phonocardiograms to an experienced observer. Of the 7993 children who underwent school-based screening in the Menghai District of Yunnan Province, Peoples Republic of China, 149 had a murmur noted by a screener. They had digital heart sounds and phonocardiograms collected with the HeartLink tele auscultation system, and underwent echocardiography by a cardiology resident from the First Affiliated Hospital of Kunming Medical University. The digital phonocardiograms, stored on a cloud server, were later remotely reviewed by a board-certified American pediatric cardiologist. Fourteen of these subjects were found to have CHD confirmed by echocardiogram. Using the HeartLink system, the pediatric cardiologist identified 11 of the 14 subjects with pathological murmurs, and missed three subjects with atrial septal defects, which were incorrectly identified as venous hum or Still's murmur. In addition, ten subjects were recorded as having pathological murmurs, when no CHD was confirmed by echocardiography during the field study. The overall test accuracy was 91% with 78.5% sensitivity and 92.6% specificity. This proof-of-concept study demonstrated the feasibility of differentiating pathologic murmurs due to CHD from normal functional heart murmurs with the HeartLink system. This field study is an initial step to develop a cost-effective CHD screening strategy in low-resource settings with a shortage of trained medical professionals and pediatric heart programs.

Estimation of influenza and severe acute respiratory illness incidence (burden) in three provinces of the Islamic Republic of Iran, 2012 and 2013

There are few estimates of influenza burden in the WHO Region for the Eastern Mediterranean. In this study we estimated the burden of severe acute respiratory infection (SARI) and influenza-associated SARI (F-SARI) in selected provinces of Islamic Republic of Iran, the trends of SARI and confirmed cases of influenza (F-SARI) over 12 months (seasonality), and the age groups most at risk. Using the electronic Iranian influenza surveillance system and data of cases in sentinel hospitals of 3 selected provinces, we estimated the monthly trend (seasonality) of incidence for SARI and F-SARI, overall incidence of SARI and F-SARI and their disaggregation by age with the aid using the Monte Carlo technique. The age groups most at-risk were children aged under 2 years and adults older than 50 years.

Assessing Bone Mineral Density Following Acute Hip Fractures: The Role of Computed Tomography Attenuation

OBJECTIVES

In older patients, bone mineral density (BMD) diminishes with age, increasing susceptibility to femoral neck fractures. Evidence has emerged that patients who should have dual x-ray absorptiometry scans to evaluate their bone health are not doing so. Because computed tomography (CT) attenuation has now been correlated with BMD thresholds relating to osteoporosis, virtually any existing CT scan that includes the L1 vertebra can be used to assess BMD. This study evaluates the utility of CT attenuation in characterizing BMD in patients after femoral neck fractures.

METHODS

The electronic medical records of adults who presented to a level I trauma center with hip fractures were evaluated for eligibility. Those with a CT scan of the abdomen or other CT scan with a complete view of the L1 vertebra were included. To measure attenuation, a region of interest was selected to include the body of the L1 vertebra in the axial plane and exclude the cortices and posterior venous complex.

RESULTS

Of the 589 patients reviewed, 217 met inclusion criteria; 112 were aged 18 to 64, while 105 were ≥65. Eight (7.1%) patients in the younger cohort had a mean CT attenuation below the 110-HU threshold set for 90% specificity, whereas 31 (29.5%) patients in the older cohort had a mean CT attenuation below this threshold. Using the 160-HU threshold set for 90% sensitivity, 39 (34.8%) patients of the younger cohort and 74 (70%) patients of the older cohort were osteoporotic; all differences in CT attenuation by age were strongly significant (P < .0001).

CONCLUSIONS

A significantly larger proportion of older patients with hip fractures had osteoporosis, helping validate the utility of CT attenuation in this context. In addition, a large proportion of these patients already had these images available, thus potentially helping limit cost and unnecessary medical investigations.

Personality influences quality-of-life assessments in adult patients after allogeneic hematopoietic SCT: results from a joint evaluation of the prospective German Multicenter Validation Trial and the Fred Hutchinson Cancer Research Center

The influence of personality on health related quality of life (QoL) and physical functioning in the setting of allogeneic hematopoietic SCT (alloHSCT) is unknown. We conducted a joint evaluation within two independent cohorts of alloHSCT recipients to investigate the impact of personality on reported QoL and physical functioning. Two-hundred-eight patients (median age 44 years, range 18-72) of cohort 1 and 93 patients (median age 55 years, range 19-79) of cohort 2 after alloHSCT were evaluated. Personality was assessed using the 24-adjective measure (AM), which measures the Big-Five personality domains and the Life Orientation Test-Revised (LOT-R), measuring optimism and pessimism. QoL was measured using the Functional Assessment of Cancer Therapy with bone marrow transplantation subscale (FACT-BMT), Short Form 36 (SF-36), the human activity profile (HAP), as well as the NIH criteria-based cGVHD activity assessment form and the Lee cGVHD symptom scale. Neuroticism was significantly associated with worse function measured by the HAP and FACT-BMT. Optimism significantly improved QoL captured by the FACT-BMT. Pessimism significantly impaired physical function captured by the HAP and SF-36. Extraversion was significantly associated with reduced depression and lower severity of cGVHD symptoms reported by the patient and the physician. The results suggest that personality traits and pre-treatment QoL assessments should be measured in clinical trials to facilitate the interpretation of QoL data.

Developing an educational scheme for undergraduate medical Curriculum: the unit of "infertility" as a sample

OBJECTIVES

To present our first experience in scheme development based on CPC philosophy in Iran.

HYPOTHESIS

One of the most important reasons of an obvious gap between medical education and professional expectations (outcomes) encountered by recent medical graduates is due to applying conventional curricula, which rely on hypothetical-deductive reasoning model. The University of Calgary has implemented a new curriculum which is organized according to 125 ways in which patients may present to a physician. In this study we will present our first experience in scheme development based on CPC philosophy in Iran.

METHODS

In 2007, research and clinical center for infertility (Yazd University of medical sciences, IRAN), began developing a full module for infertility (lesson plan) with fourteen components based on the new curricular philosophy. We recruited a scheme of infertility according to a specific way.

RESULTS

Thus, at the first step of the module creation, a scheme was made as the most important mainstay of presentation module, i.e. a structured scheme that includes all causative diseases of infertility.

CONCLUSIONS

Any effort in the organization of knowledge around schemes including in the domain of infertility would be valuable to meet some of the standards of WFME. Also, development of modules, by the teams composed of experts and students, can improve the quality of medical education.

Mortality from Pandemic Influenza A (H1N1) in Iran

BACKGROUND

Due to worldwide spread of influenza A (H1N1) virus, the World Health Organization declared the first pandemic of influenza in four decades. This study aims to report the mortality from pandemic influenza A (H1N1) in Iran population and its epidemiologic and clinical characteristics up to December 21, 2009.

METHODS

The data were obtained from all provinces and reported to center for disease control of Ministry of Health and Medical Education (MOHME) of Iran through nationwide surveillance system for influenza A (H1N1) was implemented by MOHME since April 2009.

RESULTS

Of 3672 confirmed cases of influenza A (H1N1) in Iran between 22 May and 21 December 2009, 140 (3.8%) deaths were reported, mostly in 15-65 year old (yo) age group (67%). The highest admission mortality rate was in > 65 yo group (107 deaths/1000 hospitalized cases). Of decedent patients, 54% had no long term condition or risk factor, 34% had one, 11% had two, and 1% had three. Diabetes mellitus, pregnancy, chronic respiratory diseases and hypertension were the most common underlying conditions. The most common clinical pictures of death were acute respiratory distress syndrome and viral pneumonia. Although 66% of decedent patients received oseltamivir, enough information was not available about time of onset of antiviral therapy.

CONCLUSION

As death due to influenza A (H1N1) occurs in all age groups and in those with and without any predisposing factors, we recommend health policy makers to provide influenza vaccination for people with underlying conditions and respiratory hygiene for all people.

A new classification for female infertility

Infertility is defined as the inability of a couple to conceive after 12 months of regular, unprotected intercourse. However infertility is a clinical presentation and not a disease. Thus to be able to offer a new classification, it is necessary to apply a clinical presentation (philosophy) suggested by the University of Calgary in 1991. In recent years several classification algorithms have been proposed which apply key predictors of clinical, imaging, or morphological types to determine the diseases that can cause infertility. On the other hand, an algorithm is a product of an expert's mind after many years of practice and experience, which is too difficult to understand by a medical student. However there has not been any simple schematic classification based on a logical justification applying integration of etiologies with basic science to break down etiologies into categories, subcategories and disease classes of this clinical presentation. Because etiology has also become an important criterion for the characterization of causes of infertility, a classification proposal is presented here that attempts to include all relevant (basic science) features of the causative diseases of this clinical presentation.

What kind of curriculum can better address community needs? Problems arisen by hypothetical-deductive reasoning

The aim of this study was to identify problems arisen by conventional curricula, the guidelines for development of an appropriate educational model for 21st century, and the advantages and disadvantages of the last two curricular models. The medical education literature published from 1995 through 2002 of four reputable journals in medical education were searched (Academic Medicine, Teaching and Learning in Medicine, Medical Education, and Medical Teacher). First the possibly best articles were identified. During the second screening process 76 of 180 articles were found to be highly relevant to our questions. A review of the chosen articles revealed a concept map which starts from currently applied hypothetical-deductive reasoning (HDR)-based curricula in many medical schools all around the world. Results revelaed that continuing cyclical process might be time consuming, enhance burden of faculty and might be stressful for students involved. Current issues in health care system are possibly attributable to current HDR-based curricular models including PBL. Advantages of reiterative PBL theory can not be denied, but it appears that its limited application should be mainly seen in some academic classes to develop some generic transferable skills simultaneously with other teaching methods. Therefore vast application of HDR in clinical settings is not recommended according to our study. However the relationships demonstrated between factors and outcomes mentioned in the concept map can be used to run some new studies to test some hypotheses.

LPA1 receptor-deficient mice have phenotypic changes observed in psychiatric disease

Several psychiatric diseases, including schizophrenia, are thought to have a developmental aetiology, but to date no clear link has been made between psychiatric disease and a specific developmental process. LPA(1) is a G(i)-coupled seven transmembrane receptor with high affinity for lysophosphatidic acid. Although LPA(1) is expressed in several peripheral tissues, in the nervous system it shows relatively restricted temporal expression to neuroepithelia during CNS development and to myelinating glia in the adult. We report the detailed neurological and behavioural analysis of mice homozygous for a targeted deletion at the lpa(1) locus. Our observations reveal a marked deficit in prepulse inhibition, widespread changes in the levels and turnover of the neurotransmitter 5-HT, a brain region-specific alteration in levels of amino acids, and a craniofacial dysmorphism in these mice. We suggest that the loss of LPA(1) receptor generates defects resembling those found in psychiatric disease.

In vivo characterization of basal amino acid levels in subregions of the rat nucleus accumbens: effect of a dopamine D(3)/D(2) agonist

Recent evidence demonstrates that two subdivisions of the nucleus accumbens, the dorsolateral core and the ventromedial shell can be distinguished by morphological, immunohistochemical and chemoarchitectural differences. In the present study, we measured basal levels of amino acids in microdialysates from both the shell and core subterritories of the nucleus accumbens in freely moving rats using HPLC with fluorescence detection. The effect of the dopamine D(3)/D(2) receptor agonist quinelorane (30 microg/kg s.c.) was then investigated in both subregions. With the exception of glutamate, histidine, and serine, which showed similar levels in both subterritories, alanine, arginine, aspartate, gamma-aminobutyric acid, glutamine, and tyrosine were significantly higher in the shell compared with the core. In contrast, taurine levels were significantly lower in the shell than in the core. A particularly striking difference across subregions of the nucleus accumbens was observed for basal GABA levels with a shell/core ratio of 18.5. Among all the amino acids investigated in the present study, quinelorane selectively decreased dialysate GABA levels in the core subregion of the nucleus accumbens. The results of the present study point to specific profiles of both shell and core in terms of: (1) basal chemical neuroanatomical markers for amino acids; and (2) GABAergic response to the DA D(3)/D(2) agonist quinelorane.

Effects of centrally administered orexin-B and orexin-A: a role for orexin-1 receptors in orexin-B-induced hyperactivity

RATIONALE

Orexin-A and orexin-B are hypothalamic neuropeptides derived from a 130-amino acid precursor, prepro-orexin, and are potent agonists at both the orexin-1 (OX1) and orexin-2 (OX2) receptors. Orexin-A has been ascribed a number of in vivo functions in the rat after intracerebroventricular (ICV) administration, including hyperphagia, neuroendocrine modulation and a role in the regulation of sleep-wake function. The in vivo role of orexin-B is not as clear.

OBJECTIVES

To investigate the behavioural, endocrine and neurochemical effects of orexin-B in in-vivo tests. In a number of experiments, these effects were compared with those of orexin-A.

METHODS

Experiments were carried out in male, Sprague-Dawley rats with a guide cannula directed towards the lateral ventricle. The effects of orexin-B (ICV) upon grooming behaviour were compared with those of orexin-A. The effects of orexin-B upon the motor activity response to both novel and familiar environments were assessed in an automated activity monitor. Orexin-B was tested upon startle reactivity and body temperature. Further, plasma hormones and [DOPAC+ HVA]/[DA] and [5-HIAA]/[5-HT] ratios in six brain areas were measured 40 min post-orexin-B or orexin-A.

RESULTS

The clearest behavioural response to orexin-B was increased motor activity in both novel and familiar environments. Orexin-B-induced hyperactivity was blocked by an OX1 receptor antagonist, SB-334867-A, implicating OX1 receptors in this behavioural response. In common with orexin-A, orexin-B reduced plasma prolactin and failed to influence startle reactivity. However, in contrast with orexin-A, orexin-B increased head grooming but failed to cause a robust whole body grooming response or increase plasma corticosterone levels. Further, orexin-B, but not orexin-A, increased plasma TSH and increased hypothalamic and striatal [5-HIAA]/[5-HT] ratios.

CONCLUSIONS

The present study has demonstrated a number of behavioural, neuroendocrine and neurochemical effects of orexin-B that distinguish it from orexin-A. Further, we have demonstrated a role for OX1 receptors in the actions of orexin-B upon motor activity.

Development of a protocol for the automated analysis of amino acids in brain tissue samples and microdialysates

An automated precolumn derivatisation method has been developed for the measurement of fourteen amino acids in brain tissue and microdialysate samples. The method involves labelling amino acids with naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide (CN-). The resulting highly stable N-substituted 1-cyanobenz[f]isoindole (CBI) derivatives were separated using a binary gradient elution profile and detected fluorometrically. The order of elution of the derivatised amino acids was confirmed by using liquid chromatography with fluorescence and mass spectrometric detection in tandem. Linear calibration plots were obtained for all amino acids in the range studied (0.2-12.5 microM). The limit of detection for CBI derivatives of amino acids was in the range 5-20 fmol (S/N=2) using a 5 microl injection volume. The method has been used for the measurement of amino acids in microdialysates from rat brain and tissue homogenates from different regions of mouse brain.

Orexin A activates locus coeruleus cell firing and increases arousal in the rat

The localization of orexin neuropeptides in the lateral hypothalamus has focused interest on their role in ingestion. The orexigenic neurones in the lateral hypothalamus, however, project widely in the brain, and thus the physiological role of orexins is likely to be complex. Here we describe an investigation of the action of orexin A in modulating the arousal state of rats by using a combination of tissue localization and electrophysiological and behavioral techniques. We show that the brain region receiving the densest innervation from orexinergic nerves is the locus coeruleus, a key modulator of attentional state, where application of orexin A increases cell firing of intrinsic noradrenergic neurones. Orexin A increases arousal and locomotor activity and modulates neuroendocrine function. The data suggest that orexin A plays an important role in orchestrating the sleep-wake cycle.

Characterization of functional domains within Smad4/DPC4

Smad proteins are a family of highly conserved, intracellular proteins that signal cellular responses downstream of transforming growth factor-beta (TGF-beta) family serine/threonine kinase receptors. One of these molecules, Smad4, originally identified as the candidate tumor suppressor gene dpc-4, reconstitutes TGF-beta- and activin-dependent transcriptional responses in Smad4 null cell lines and interacts in a ligand-dependent manner with other Smad family members in both TGF-beta, activin, and bone morphogenetic protein-2/-4 pathways. Here, we used an assay based on the restoration of ligand-dependent transcriptional responses in a Smad4 null cell line to characterize functional domain structures within Smad4. We showed that restoration of TGF-beta-induced transcriptional responses by Smad4 was inhibited by co-transfection with a kinase dead TGF-beta type II receptor and that constitutive activation was blocked with TGF-beta neutralizing antibodies, confirming the essential role of Smad4 in TGF-beta signaling. Using a series of Smad4 mutation, deletion, and Smad1/Smad4 chimera constructs we identified a 47-amino acid deletion within the middle-linker region of Smad4 that is essential for the mediation of signaling responses. In addition, we showed that the NH2-terminal domain of Smad4 augments ligand-dependent activation associated with the middle-linker region, indicating that there is a distinct ligand-response domain within the N terminus of this molecule.

Expression of a dominant-negative mutant TGF-beta type II receptor in transgenic mice reveals essential roles for TGF-beta in regulation of growth and differentiation in the exocrine pancreas

Using a dominant-negative mutant receptor (DNR) approach in transgenic mice, we have functionally inactivated transforming growth factor-beta (TGF-beta) signaling in select epithelial cells. The dominant-negative mutant type II TGF-beta receptor blocked signaling by all three TGF-beta isoforms in primary hepatocyte and pancreatic acinar cell cultures generated from transgenic mice, as demonstrated by the loss of growth inhibitory and gene induction responses. However, it had no effect on signaling by activin, the closest TGF-beta family member. DNR transgenic mice showed increased proliferation of pancreatic acinar cells and severely perturbed acinar differentiation. These results indicate that TGF-beta negatively controls growth of acinar cells and is essential for the maintenance of a differentiated acinar phenotype in the exocrine pancreas in vivo. In contrast, such abnormalities were not observed in the liver. Additional abnormalities in the pancreas included fibrosis, neoangiogenesis and mild macrophage infiltration, and these were associated with a marked up-regulation of TGF-beta expression in transgenic acinar cells. This transgenic model of targeted functional inactivation of TGF-beta signaling provides insights into mechanisms whereby loss of TGF-beta responsiveness might promote the carcinogenic process, both through direct effects on cell proliferation, and indirectly through up-regulation of TGF-betas with associated paracrine effects on stromal compartments.

Effects of Flt3 ligand and interleukin-7 on in vitro growth of acute lymphoblastic leukemia cells

We investigated the effects of Flt3/Flk-2 ligand (FL) and interleukin-7 (IL-7) on DNA synthesis and proliferation of blast cells from patients with acute lymphoblastic leukemia (ALL). After 7 days of serum-free suspension culture of 19 samples, FL induced maximal DNA synthesis in two cases, whereas the combination of FL and IL-7 did so in another eight samples with a stimulation index (SI) >2. However, the number of viable cells after 7 days of liquid culture decreased in all but one sample. In this case of a pre-pre-B-ALL with a translocation t(4;11), FL induced dose-dependent proliferation (maximal 100 ng/mL) and cells stimulated with FL could be cultured for up to 4 weeks. A homogeneous population with 98% CD19-positive cells was detected before and after culture, and there was no evidence of nonleukemic cell proliferation as determined by immunophenotyping. The flt3 gene was transcribed in all seven cases studied by reverse-transcriptase polymerase chain reaction (RT-PCR). In the ALL cells responsive to FL, the expression of functional Flt3 receptors was confirmed by demonstrating FL-dependent tyrosine phosphorylation of Flt3. Furthermore, FL-dependent tyrosine phosphorylation of cellular proteins of estimated molecular weights of 70, 115, and 140 kD was detectable in these cells. These data demonstrate the functional heterogeneity of ALL samples and show that functional Flt3 receptors capable of mediating FL-dependent mitogenic signaling are expressed in a subset of ALL.