Co-localization of patched and activated sonic hedgehog to lysosomes in neurons

We demonstrate co-localization of the Patched 1 (Ptc1) receptor and its ligand sonic hedgehog (Shh) in lysosomes suggests an intracellular sorting mechanism for this receptor and its ligand. Treatment of murine brain primary cultures and a human teratoma cell line with the N-terminal activated form of Shh (ShhNT), a Ptc1-Shh complex was observed in lysosomes. Consistent with this interaction, Western immunoblot analysis revealed intracellular localization of native Ptc1 and ShhNT. Examination of the topological model of the Ptc1 receptor revealed a number of Yxxphi lysosomal targeting sequences consistent with our observations for Ptc1 sorting.     

Epicardial coronary artery responses to acetylcholine are impaired in hypertensive patients.

Hypertension is a risk factor for coronary atherosclerosis possibly via an adverse effect on the vascular endothelium. Endothelium-mediated relaxation is impaired in animal models of hypertension. However, the effects of hypertension on human coronary artery endothelial cell function are unknown. To test whether endothelium-mediated relaxation is impaired in the coronary arteries of patients with hypertension, we studied 14 patients with essential hypertension requiring therapy and 15 nonhypertensive control patients undergoing cardiac catheterization. All had angiographically normal, smooth-appearing coronary arteries. Patients were matched for age and other coronary atherosclerosis risk factors. To assess endothelial cell function, the endothelium-dependent vasodilator acetylcholine (ACh, 0.01, 0.1, and 1.0 microM) and the endothelium-independent vasodilator nitroglycerin (40 micrograms) were selectively infused into the left anterior descending or circumflex coronary artery. Diameter change (expressed as percent) was assessed using quantitative angiography. There was a marked vasoconstrictor response to serial doses of ACh in hypertensive patients (-7%, -21%, and -27%) compared with control patients (-4%, -5%, and -7%) (p less than 0.02). The vasodilator response to nitroglycerin was preserved in hypertensive patients (+29%) and control patients (+25%) (p = NS), suggesting that endothelial cell dysfunction accounted for the differences in response to ACh. Thus, patients with hypertension have an accentuated coronary vasoconstrictor response to ACh, suggesting that endothelium-mediated regulation of coronary vascular tone is impaired by essential hypertension. This may reflect more generalized coronary endothelial changes contributing to the pathogenesis of atherosclerosis as well as hypertension.     

SCAI expert consensus update on best practices in the cardiac catheterization laboratory

The current document commissioned by the Society for Cardiovascular Angiography and Interventions (SCAI) and endorsed by the American College of Cardiology, the American Heart Association, and Heart Rhythm Society represents a comprehensive update to the 2012 and 2016 consensus documents on patient-centered best practices in the cardiac catheterization laboratory. Comprising updates to staffing and credentialing, as well as evidence-based updates to the pre-, intra-, and post-procedural logistics, clinical standards and patient flow, the document also includes an expanded section on CCL governance, administration, and approach to quality metrics. This update also acknowledges the collaboration with various specialties, including discussion of the heart team approach to management, and working with electrophysiology colleagues in particular. It is hoped that this document will be utilized by hospitals, health systems, as well as regulatory bodies involved in assuring and maintaining quality, safety, efficiency, and cost-effectiveness of patient throughput in this high volume area.     

Pathology of head trauma

This article reviews the essential primary and secondary injuries attributable to traumatic brain injury (TBI) which causes one third of all injury deaths in the United States. Motor vehicle crashes, falls, assaults, guns, sports, and recreational activities are the major causes of TBI. Secondary peak incidences of TBI occur in infants and children and the elderly. Conditions that increase risk for accidents include alcoholism, prior head injury, prior meningitis, seizure disorders, mental retardation, and psychiatric disorders. However, gunshot wounds to the head are steadily increasing and since 1990 have caused more deaths each year than motor vehicle accidents. The incidence, severity, etiology, and specific types of injuries have been assessed in clinicopathologic studies of head injuries. The pathologic features of both the primary and secondary lesions attributed to TBI should be understood by anyone caring for head-injured patients. The computed tomography (CT) and magnetic resonance (MR) images mirror the pathologic abnormalities found in head trauma. Radiologists must accurately interpret the CT and MR images of injured patients. Forensic pathologists have long appreciated the characteristic focal lesions, such as coup and contracoup contusions, that occur in falls or vehicle accidents, but the understanding of diffuse injuries has been more elusive. Understanding the nature of the focal and diffuse injuries is critical to understanding the morbidity and mortality of brain injury.     

Apoptosis,PCNA and p53 in hepatocellular carcinoma

BACKGROUND/AIMS: The regulation of cell number is present in normal tissues but is lost in malignant neoplasms. The real meaning of these alterations is not well known. Apoptosis is the programmed cell death. p53, a tumor suppressor gene, has an important function in DNA repair and in regulation of apoptosis. Mutations of p53 were described in malignant tumors and can be the cause of the alterations of this balance. Proliferating cell nuclear antigen is an auxiliary protein present during G1-late phase and S phase. The aim of this study was to compare cell proliferation, apoptosis and expression of p53 in hepatocellular carcinoma. METHODOLOGY: Fifteen patients with hepatocellular carcinoma were included. Ten patients were men. The mean age of the patients was 55.53 years old. Cirrhosis was positive in nine patients, 5 were HBsAg positive and none were anti-HCV positive. The mean level of AST and ALT were respectively, 62.79 and 50.64. Formalin-fixed and paraffin-embedded tissues from these patients were examined retrospectively. Apoptosis were measured by counting the number of apoptotic bodies in 500 tumoral cells. The expression of p53 oncogene and the PCNA were determined by immunohistochemical method, using avidin-biotin method (DAKO). The p53 were considered positive when the number of positive nuclei was more than 5% of the tumoral cells. The proliferative activity was determined by proliferating cell nuclear antigen labeling index. RESULTS: The proliferating cell nuclear antigen-labeling index ranged from 0.48 and 0.95 (mean: 0.82). The p53 was positive in five patients. The number of apoptotic bodies counted ranged from 0 to 15 (mean: 4.20). There were no differences among p53 and the mean levels of proliferating cell nuclear antigen labeling index or p53 and the number of apoptotic bodies. CONCLUSIONS: A high index of proliferation has been shown in the patients studied. Positivity of p53 was seen in less than a half of the patients (35.71%). The index of apoptotic bodies observed was very low. Our results suggest that high-grade proliferation is not associated with increase of apoptosis in hepatocellular carcinoma.     

The conserved PI3'K/PTEN/Akt signaling pathway regulates both cell size and survival in Drosophila

Akt (or PKB) is an oncogene involved in the regulation of cell survival. Akt is regulated by phosphatidylinositol 3-OH kinase (PI3'K) signaling and has shown to be hyperactivated through the loss of the PTEN tumor suppressor. In Drosophila, insulin signaling as studied using the Drosophila IRS-4 homolog (Chico) has been shown to be a crucial regulator of cell size. We have studied Drosophila Akt (Dakt1) and have shown that it is also involved in the regulation of cell size. Furthermore we have performed genetic epistasis tests to demonstrate that in Drosophila, PI3'K, PTEN and Akt comprise a signaling cassette that is utilized during multiple stages of development. In addition, we show that this signaling cassette is also involved in the regulation of cell survival during embryogenesis. This study therefore establishes the evolutionary conservation of this signaling pathway in Drosophila. Oncogene (2000) 19, 3971 - 3977.     

Congenital cholesteatoma of the middle ear in children

Congenital cholesteatoma, once considered to be a rarity, has shown an exponential increase in its incidence as evidenced by numerous clinical studies over the past decade. No explanation has been offered for this phenomenon. A review of the literature indicates that the definition of "congenital cholesteatoma" has strayed from the original one formulated by Derlacki and Clemis, which included a cholesteatoma medial to an intact tympanic membrane, without prior history of aural infections. Allowing patients with recurrent otitis media into studies may have contributed to a "false positive" rise in the incidence of this condition. This article reviews 19 cases of cholesteatomas behind intact tympanic membranes, treated at the Montreal Children's Hospital over a 10-year period. They represent 22% of the entire cholesteatoma population. There appears to be two groups of patients, each with a distinct clinical presentation that correlates well with the surgical outcome. Whether this implies different pathogenetic mechanisms remains unclear.     

Left ventricular hypertrophy with outflow tract obstruction-a complication of dexamethasone treatment for subglottic stenosis

To our knowledge, this is the 1st reported case of steroid-induced obstructive cardiomyopathy in a child being treated for subglottic stenosis. As well, although born at 27 weeks, our patient was over 4 kg and 4 months of age (44 weeks corrected gestational age). This appears to be a phenomenon chiefly involving premature babies in the neonatal period with no reports of this occurring in patients greater than 40 weeks corrected gestational age. Signs of cardiac hypertrophy include tachycardia, new cardiac murmur, increased oxygen requirements, decreased urine output, and decreased peripheral perfusion. Diagnosis and eventual recovery was confirmed with serial echocardiograms. Knowledge of this serious side effect of dexamethasone will allow otolaryngologists to intervene early and prevent a potentially deadly complication.     

Sleep and breathing on the first night after adenotonsillectomy for obstructive sleep apnea

Adenotonsillectomy (T&A) has established effectiveness for the treatment of obstructive sleep apnea (OSA). However, more than 20% of children with OSA have respiratory compromise requiring medical intervention in the postoperative period. The reasons for this complication are not well-defined. We aimed to compare the nature and severity of sleep-disordered breathing in children with mild and severe OSA on the first night following adenotonsillectomy. Ten children were classified into groups of mild and severe OSA, based on preoperative testing. On the first night after T&A, they underwent polysomnography, including electroencephalograph, submental electromyography, bilateral electro-oculograms, monitoring of respiratory movements, heart rate, ECG, and oxygen saturation. Sleep-disordered breathing was assessed by the apnea-hypopnea index, the SaO(2) nadir, and the desaturation index, including dips in saturation below 90% (DI(90)). Sleep quality was assessed by sleep efficiency, time spent in each sleep state, and respiratory arousal index. Obstructive events occurred postoperatively in all children, but were more frequent in those with severe OSA preoperatively: the median (interquartile range) mixed/obstructive apnea/hypopnea indicies were 6.9 (2.2-9.8) events/hr and 21.5 (15.1-112.1) events/hr for the mild OSA group and the severe OSA group, respectively (P = 0.009). Obstructive events were the major cause of desaturation during sleep postoperatively. Sleep quality was severely disrupted in both groups, with reductions in both slow-wave sleep and rapid eye movement sleep. In conclusion, despite removal of obstructing lymphoid tissue, upper airway obstruction occurred on the first postoperative night in children with OSA. This study is the first to demonstrate the mechanism of respiratory compromise after adenotonsillectomy, a common postoperative complication in children with severe OSA.