Mubarak Al-Shraim

Recent advances in benefits and hazards of engineered nanoparticles

Over recent decades, engineered nanoparticles are increasingly produced as the result of the rapid development in nanotechnology. They are currently used in a wide range of industrial and public sectors including healthcare, agriculture, transport, energy, materials, and information and communication technologies. As the result, an increasing concern has been raised over the potential impacts of engineered nanoparticles to human health. In the light of this, it is the purpose of the present review to discuss: (1) novel properties of engineered nanoparticles particularly in biomedical sciences, (2) most recently reported adverse effects of manufactured nanoparticles on human health and (3) different aspects of toxicological risk assessment of these nanoparticles.

Thymoquinone ameliorates lead-induced brain damage in Sprague Dawley rats.

The present study aims to investigate the protective effects of thymoquinone, the major active ingredient of Nigella sativa seeds, against lead-induced brain damage in Sprague-Dawley rats. In which, 40 rats were divided into four groups (10 rats each). The first group served as control. The second, third and fourth groups received lead acetate, lead acetate and thymoquinone, and thymoquinone only, respectively, for one month. Lead acetate was given in drinking water at a concentration of 0.5 g/l (500 ppm). Thymoquinone was given daily at a dose of 20mg/kg b.w. in corn oil by gastric tube. Control and thymoquinone-treated rats showed normal brain histology. Treatment of rats with lead acetate was shown to produce degeneration of endothelial lining of brain blood vessels with peri-vascular cuffing of mononuclear cells consistent to lymphocytes, congestion of choroid plexus blood vessels, ischemic brain infarction, chromatolysis and neuronal degeneration, microglial reaction and neuronophagia, degeneration of hippocampal and cerebellar neurons, and axonal demyelination. On the other hand, co-administration of thymoquinone with lead acetate markedly decreased the incidence of lead acetate-induced pathological lesions. Thus the current study shed some light on the beneficial effects of thymoquinone against neurotoxic effects of lead in rats.

Pancreatic Heterotopia in the Gallbladder Associated with Chronic Cholecystitis: A Rare Combination

CONTEXT Pancreatic heterotopia is a rare pathologic entity, previously reported in the stomach, duodenum and jejunum. It is mostly asymptomatic and rarely gives rise to complications. Localization of pancreatic heterotopia in the gallbladder is extremely rare and can be associated with cholecystitis or cholecystolithiasis. CASE REPORT We herein describe a case of a 39-year-old man who presented with biliary type pain with ultrasonographic evidence of a gallbladder polyp. Laparoscopic cholecystectomy was performed with uneventful recovery. Pathologic examination of the gallbladder detected a heterotopic focus of pancreatic tissue in its wall, associated with chronic cholecystitis with no gallstones. CONCLUSION Pancreatic heterotopia of the gallbladder is a very rare entity with unknown clinical significance. Awareness of this condition may facilitate its recognition which may shed more light on its clinical significance.

Recent advances in autophagy-based neuroprotection

Macroautophagy is a highly regulated intracellular process that, under certain circumstances, delivers cytoplasmic components to the lysosomes for degradation. It consists of several sequential steps including initiation and nucleation, double membrane formation and elongation, formation and maturation of autophagosomes and finally autophagosomes/lysosomes fusion and degradation of intra-autophagosomal contents by lysosomal enzymes. After decades of considering autophagy as a cell death pathway, it has recently been shown to have a survival function through clearing of protein aggregates and damaged cytoplasmic organelles in response to a variety of stress conditions. Most recently, there is increasing evidence from literature revealing that autophagy induction may combat neurodegeneration. In the light of this, our current review tried to address the recent advances in the role of induced autophagy in neuroprotection with a particular focus on its contribution in the most common neurodegenerative disorders like Alzheimer’s disease, Parkinson’s disease and Huntington’s disease.

Recent advances on the role of neurogenesis in the adult brain: therapeutic potential in Parkinson’s and Alzheimer’s diseases

BACKGROUND Generation of nascent functional neurons from neural stem cells in the adult brain has recently become largely accepted by the neuroscience community. In adult mammals including humans, the process of neurogenesis has been well documented in two brain regions; the subventricular zone of the lateral ventricles and the subgranular zone in the dentate gyrus of the hippocampus. METHOD Some evidence has indicated neurogenesis in other regions of the adult mammalian brain such as the neocortex, cerebellum, striatum, amygdala and hypothalamus. These discoveries question a long standing dogma on nervous system regeneration and provide medical science with potential new strategies to harness the process of neurogenesis for treating neurological disabilities and neurodegenerative diseases. CONCLUSION In this current review, we address the most recent advances on the role of neurogenesis in the adult brain and therapeutic potential in the two most common neurodegenerative disorders, Parkinsons and Alzheimers diseases.

Ultrastructural Changes of Smooth Muscles in Varicocele Veins

Background: Varicocele is a dilatation of the pampiniform venous plexus and internal spermatic veins. It affects about 15–20% of male population and can cause infertility. Objective: To describe the most significant ultrastructural changes of the smooth muscle cells in grade 3 varicocele veins. Methods: The authors analyzed 2- to 3-cm tracts of pampiniform venous plexus from 20 patients who underwent varicocelectomy for left varicocele. Light microscopic examination was performed with Van Gieson’s stain. Ultrastructural examination was done using scanning and transmission electron microscopy. Results: Light microscopic examination revealed irregularity and separation of medial smooth muscle cells by abundant collagen fibers in varicocele veins. On scanning electron microscopy, the medial layer of varicocele veins showed hypertrophy, irregularity, and separation of the outer longitudinal smooth muscle cells and deposition of numerous fatty globules in between muscle fibers. Transmission electron microscopy showed marked indentation and chromatin condensation of the nucleus, presence of clear vacuoles and myelin figures in the cytoplasm and plasmalemmal projections and formation of ghost bodies. Furthermore, smooth muscle cells were found to have pseudopodia-like projections around adjacent elastic and collagen fibers. Conclusions: The degenerative changes observed in smooth muscle cells and presence of abundant collagen fibers in the medial layer may contribute to the development of the varicocele of pampiniform venous plexus. Further molecular studies are required to shed more light for the underlying mechanism.

Acute occlusive mesenteric ischemia in high altitude of southwestern region of Saudi Arabia

BACKGROUND AND OBJECTIVES Mesenteric ischemia which can be acute or chronic depending on the rapidity of compromised blood flow produces bowel ischemia, infarction, bacterial transmigration, endotoxemia, multisystem organ failure and death. High altitude can precipitate thrombosis because of hypobaric hypoxia and its effect on coagulation system. The objectives of this study are to determine the risk factors, clinical presentation, type and pattern of acute occlusive mesenteric ischemia in high-altitude of southwestern region of Saudi Arabia. MATERIALS AND METHODS We reviewed the records of all the patients with acute occlusive mesenteric ischemia admitted to the Armed Forces Hospital, southern region, Kingdom of Saudi Arabia during the period of 2005 to 2010, and compiled data including demographics, clinical presentation, risk factors, preoperative investigations, management, histopathological examination, and complications. The cases of mesenteric ischemia resulting from conditions such as volvulus and strangulated hernias were excluded. RESULTS Our study included 21 patients, 10 (48%) men and 11 (52%) women with a mean age of 56 years (SD 14). Abdominal pain was the most common presenting symptoms. CT angiography depicted occlusive arterial disease in 8 patients (38%) and venous thrombosis in 13 patients (62%). Diabetes mellitus was the most frequent risk factor for arterial mesenteric ischemia. Chronic liver disease particularly liver cirrhosis was the most prominent risk factor for venous mesenteric thrombosis. Intestinal ischemia was confirmed by histopathological examination. CONCLUSION Acute occlusive mesenteric ischemia can mimic other more common intra-abdominal diseases clinically; therefore a high index of suspicion is required particularly for patients with relevant risk factors to prompt early diagnosis and intervention. Venous mesenteric thrombosis was more common than arterial mesenteric ischemia in our region.

Ultrastructural Changes of the Smooth Muscle in Esophageal Atresia

Abstract Esophageal atresia (EA) with or without tracheo-esophageal fistula (TEF) is a relatively rare congenital anomaly. Despite the advances in the management techniques and neonatal intensive care, esophageal dysmotility remains a very common problem following EA/TEF repair. Our current study aimed to describe the most significant ultrastructural changes of the smooth muscle cells (SMCs) trying to highlight some of the underlying mechanisms of esophageal dysmotility following EA/TEF repair. Twenty-three biopsies were obtained from the tip of the lower esophageal pouch (LEP) of 23 patients during primary repair of EA/TEF. Light microscopic examination was performed with hematoxylin and eosin (HE), and Van Gieson’s stains. Ultrastructural examination was done using transmission electron microscopy (TEM). Histopathological examination showed distortion of smooth muscle layer and deposition of an abundant amount of fibrous tissue in-between smooth muscles. Using TEM, SMCs exhibited loss of the cell-to-cell adhesion, mitochondrial vacuolation, formation of myelin figures, and apoptotic fragmentation. There were also plasmalemmal projections and formation of ghost bodies. Interestingly, SMCs were found extending pseudopodia-like projections around adjacent collagen fibers. Engulfed collagen fibers by SMCs underwent degradation within autophagic vacuoles. Degeneration of SMCs and deposition of abundant extracellular collagen fibers are prominent pathological changes in LEP of EA/TEF. These changes might contribute to the pathogenesis of esophageal dysmotility in patients who have survived EA/TEF.

Basidiobolomycosis of the Colon Masquerading as Stenotic Colon Cancer

Basidiobolus ranarum is a widespread saprophyte fungus with pathogenic potential. It affects mainly the subcutaneous tissues of the trunk and limbs. Relatively recently, occasional reports of gastrointestinal basidiobolomycosis appeared in the literature. Due to the rarity of the condition and the nonspecific presenting features, the correct diagnosis is usually hard to reach. In this paper, we describe the clinical course of an otherwise healthy female, who presented with a colonic mass. She received subtotal colectomy followed by oral itraconazole, with successful outcome.

Ultrastructural changes of kidney in Schistosoma mansoni-infected mice

ABSTRACT Schistosomiasis is the second threatening parasitic disease after malaria and among Schistosoma spp., Schistosoma mansoni (S. mansoni) affects about 100 million people in tropic regions in Africa and South America. The current study was carried out to investigate ultrastructural changes of the kidney in mice infected with cercariae of S. mansoni, in which 20 Swiss albino mice of 60-day-old were assigned into two groups (10 each). Control group received 1 ml normal saline by intraperitoneal route. Model group were intraperitoneally infected with 1 ml normal saline containing 40 cercariae of S. mansoni/mouse. After 60 days of infection, specimens from the kidneys of both control and infected mice were obtained and processed for transmission electron microscopy (TEM) examination. The main ultrastructural changes were observed in both glomeruli and tubules. Glomerular findings included irregular thickening and splitting of the glomerular basement membrane (GBM), flattening and effacement of the foot processes of podocytes, and proliferation of mesangial cells. Tubular changes were in the form of swelling, atrophy and vacuolation of tubular epithelial cells, and presence of autophagic vacuoles. In conclusion, adopting TEM shows a number of ultrastructural changes in the kidneys of mice infected with cercariae of S. mansoni, most notably thickening and splitting of GBM and flattening and effacement of foot processes of podocytes and tubular autophagic vacuoles. These changes are still unraveled well in the literature.