SummarySubclavian ‘steal’ phenomenon is a function of the proximal subclavian artery (SA) steno-occlusive disease, with subsequent retrograde blood flow in the ipsilateral vertebral artery (VA). The symptoms from the compromised vertebrobasilar and brachial blood flows constitute the subclavian steal syndrome (SSS), and include paroxysmal vertigo, drop attacks and/or arm claudication. Once thought to be rare, the emergence of new imaging techniques has drastically improved its diagnosis and prevalence. The syndrome, however, remains characteristically asymptomatic and solely poses no serious danger to the brain. Recent studies have shown a linear correlation between increasing arm blood pressure difference with the occurrence of symptoms. Atherosclerosis of the SA remains the most common cause. Doppler ultrasound is a useful screening tool, but the diagnosis must be confirmed by CT or MR angiography. Conservative treatment is the initial best therapy for this syndrome, with surgery reserved for refractory symptomatic cases. Percutaneous angioplasty and stenting, rather than bypass grafts of the subclavian artery, is the widely favored surgical approach. Nevertheless, large, prospective, randomized, controlled trials are needed to compare the long-term patency rates between the endovascular and open surgical techniques.
The superior mesenteric artery (SMA) syndrome is a rare but potentially life-threatening gastrointestinal condition. Over the years, it has been referenced by several names, the most common of which is Wilkie's syndrome. These numerous terminologies have made it difficult to estimate its true frequency in the general population. Common symptoms associated with this syndrome include intermittent postprandial abdominal pain, nausea, and bilious vomiting. Our review revealed that although it is currently well-defined in the literature, the diagnosis of SMA syndrome remains challenging as other disorders can mimic its presentation. However, CT angiography is currently favored in the literature for diagnosis as it can not only show the narrowed aorto-mesenteric angle and distance, but also the extent of duodenal obstruction. In addition, we found no consensus on the preferred mode of therapy once SMA syndrome is diagnosed. The agreement among authors is that the treatment options should be based on severity of the disease, using conservative measures as the first line of therapy in mild SMA syndrome. Duodenojejunostomy is the preferred surgical approach when conservative management fails, or in severe cases.
Introduction Grisel's syndrome (GS) is a rare otolaryngologic condition that involves rotatory subluxation of the atlantoaxial joint in the absence of trauma. Sir Charles Bell was the first to describe this condition in 1830. However, it was named after Pierre Grisel, a French ENT specialist who in 1930 described three such cases in children. Methods Using standard search engines, we reviewed the most recent literature regarding GS with special attention to its pathogenesis, natural history, and recent treatment options. Results Although defined over 80 years ago, the exact pathogenesis leading to GS is still not completely understood. Nevertheless, it occurs mainly as a complication of upper respiratory tract infections and/or surgical interventions in the head and neck. Most recent studies postulate that the spread of septic emboli from such infection nidus via the pharyngovertebral veins to the periodontoid vascular plexus could be the most likely cause. The diagnosis of GS is made by both clinical assessment as well as radiologic confirmation with either CT scan or MRI. Our review found out that most authors favor immobilization with a soft collar and antibiotics over surgical correction in the initial management of GS. Surgery is reserved for severe and refractory cases. Conclusion GS remains a rare, but potentially lethal children condition. Early diagnosis and treatment is crucial to its management and prognosis.
Sigmoid volvulus (SV) is the third leading cause of colon obstruction in adults. In infants and children, it is exceedingly rare with only sporadic cases reported so far. SVs from secondary causes, with congenital megacolon being the most important, are nevertheless more common in young people. The etiology of this disorder is not completely understood. It is known to occur in the setting of redundant sigmoid loop, which rotates around its narrow and elongated mesentery. Although the latter occurs in the setting of constipation, a congenitally elongated colon, and other predisposing factors, there is no consensus on the precipitating factor leading to SV formation. The symptoms are suggestive of small bowel obstruction, but the presentations can be acute or indolent. Plain abdominal radiography is used to diagnose SV in most cases with computed tomography scan or magnetic resonance imaging as the confirmatory tests when necessary. After it has been untwisted, the definitive and standard therapy for SV is sigmoid resection and primary anastomosis. The nonresective alternatives have also been widely used with mixed success, but a large, randomized controlled trial is needed to compare their efficacy with resection and primary anastomosis. Laparoscopic surgery in SV management is unwarranted and costly. Complications of SV include hemorrhagic infarction, perforation, septic shock, and death. The mortality data from SV vary, but the latest literature cites an overall range of 14 to 45 per cent.
From our study, we can conclude that contrary to previous reports indicating a plateau in the incidence rates of pediatric brain tumors since the mid-1980s, there has been an increase from 1973 to 2008. Potential causes include environmental carcinogens, but more research is needed to investigate the factors behind this sustained rise in incidence over the years.
Lungs receive the bulk of their blood supply through the pulmonary arteries. The bronchial arteries, on the other hand, vascularize the bronchi and their surroundings. These two arteries anastomose near the alveolar ducts. Contrary to the pulmonary circulation which is fairly well studied, the bronchial arteries have been appreciated more by their absence, and in some cases, by an interruption in the pulmonary arterial flow. Therefore, a more accurate anatomical and functional knowledge of these atherosclerosis-resistant vessels is needed to help surgeons and clinicians to avoid iatrogenic injuries during pulmonary interventions. In this review, we have revisited the anatomy and pathophysiology of the bronchial arteries in humans, considering the recent advances in imaging techniques. We have also elaborated on the known clinical applications of these arteries in both the pathogenesis and management of common pulmonary conditions.
The ganglion impar is often overlooked as a component of the sympathetic nervous system. Despite its obscurity, this ganglion provides a pathway for neurons by accommodating postganglionic sympathetics, visceral afferents, and somatic fibers traveling to and from the pelvis. Its classic anatomic location as described in the 1720's held up until recently, with the current literature now revealing a great deal of anatomical variability. This variation becomes important when the ganglion impar is used as a treatment target for patients with chronic pelvic pain - its primary clinical implication. The aim of this review was to provide a better understanding of the anatomy of ganglion impar, accounting for variation in size, shape, and location. In addition, the clinical importance and treatment modalities associated with the ganglion impar are outlined.
In this computational study, geometric factors are calculated by applying semi-empirical methods (PM3) that support experimental evidence from this lab where bryostatins can bind trivalent iron with six Fe-O bonds forming an octahedral geometry. The geometric factors are calculated for all 20 structures (Fe3+ bound to bryostatin 1-20) as a neutral, monovalent, and divalent species. The average Fe-O bond distances and bond angles are compared to those of known marine and terrestrial siderophores. From these two data sets, we then examined other known marine natural products (MNPs) that can form a hexavalent complex with six Fe-O bonds and draw conclusions about their potential biological role as marine siderophores. This computational data indicates that Fe(III) strongly bonds to a host of MNPs, increasing their water solubility, contracting their structure, hence allowing transport through cell membranes more readily, and in some cases, stabilizing ester bonds that are susceptible to hydrolysis. It is argued that administering medicinally bryostatin, its analogs or other MNPs as a ferric complex, holds some fundamental chemical advantages compared to its administration as a neutral uncomplexed species.
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