Bone nodules on chitosan-polygalacturonic acid-hydroxyapatite nanocomposite films mimic hierarchy of natural bone

The ultimate goal of bone tissue engineering is to develop bony tissues on tissue engineered constructs that mimic the native bone. Nanoscale characterization of in vitro generated bony tissues on engineered scaffolds is essential to understanding both the physical and mechanical characteristics of the engineered bone. Bone nodule formation, a typical early indicator of bone formation was observed on chitosan-polygalacturonic acid-hydroxyapatite (Chi-PgA-HAP) nanocomposite films without the use of differentiating media. Thus, the Chi-PgA-HAP substrates designed are osteoinductive and provide an appropriate microenvironment for cell organization and tissue regeneration. Imaging using atomic force microscopy revealed several levels of hierarchical structures of bone in the bone nodules, consisting of mineralized collagen fibers, fibrils and mineral deposits in extrafibrillar spaces. The nanoscale elastic properties of the collagen and mineral crystals were found to be in close agreement with the experimental and simulations results on natural bone reported in the literature. Fourier transform infrared spectroscopy experiments indicate the presence of collagen and biological apatite in bone nodules exhibiting the characteristics of newly precipitated, immature bone. Collectively, our structural, chemical, and mechanical analyses support the conclusion that synthetic bone nodules mimic the hierarchy of natural bone.     

A rare case of coexistent carcinoma of the colon with tuberculosis

This is a case report of a 35-year-old female who presented with acute intestinal obstruction initially diagnosed as ileocaecal tuberculosis. She was submitted to exploratory laparotomy with a right hemicolectomy for a non-passable ileocaecal mass. Histopathology showed colon cancer with tuberculosis both in the colon as well as the mesenteric lymph node. In addition to its pathological rarity, this case is of particular interest, because it highlights the diagnostic dilemma and therapeutic challenge associated with such a condition.     

Treatment of partial-thickness burns: a prospective, randomized trial using Transcyte

BACKGROUND: The purpose of the present study was to compare the effectiveness of three burns dressings (TransCyte, a bio-engineered skin substitute; Biobrane; and Silvazine cream (silver sulphadiazine and 0.2% chlorhexidine)), in treating children with partial-thickness burns. The primary objective was to determine the days until > or =90% re-epithelialization. The secondary objectives were to evaluate the number of wounds requiring autografting and the number of dressing changes/local wound care required. METHODS: Study wounds were identified on each patient and the patients were randomized to receive TransCyte or Biobrane or Silvazine. Assessment of study wound closure began at 2 days after treatment and continued at least every other day thereafter until the wounds re-epithelialized or were autografted. A laser Doppler imaging system was used as an adjunct to assessing the depth of the burn. RESULTS: Thirty-three patients with 58 wound sites enrolled in the study (TransCyte, n = 20, Biobrane, n = 17; Silvazine, n = 21). Mean time to re-epithelialization was 7.5 days for TransCyte, 9.5 days for Biobrane, and 11.2 days for Silvazine. The number of wounds requiring autografting were 5/21 (24%) for Silvazine, 3/17 (17%) for Biobrane, and 1/20 (5%) for TransCyte. CONCLUSIONS: When used in partial-thickness burns in children, TransCyte promotes fastest re-epithelialization and required less overall dressings then Biobrane or Silvazine. Patients who received Silvazine or Biobrane require more autografting than those treated with TransCyte.     

Coronary Artery Disease in Patients with Ischemic Stroke and TIA

Background and ObjectivesIschemic stroke (IS) and coronary artery disease (CAD) share common risk factors and one may be the harbinger of the other. We aimed to study prevalence of symptomatic and asymptomatic CAD in a cohort of consecutive patients with IS and assess its relationship with intracranial and extracranial large artery cerebrovascular disease (LAD).MethodsAll consecutive eligible IS and Transient Ischemic Attack (TIA) patients were recruited into the study. Both clinically suspected and asymptomatic patients (N = 259) underwent myocardial Stress-rest Gated Technetium-99m (Tc99m) MIBI Myocardial Perfusion SPECT scan performed on a dual head SPECT-CT to estimate evidence of myocardial ischemia.ResultsThree hundred patients completed the study. Forty one patients were previously diagnosed cases of definitive CAD. Twelve patients were clinically suspected to have CAD and 247 patients were asymptomatic. Among these, 12 patients (4.81%) had a positive SPECT. The overall prevalence of CAD was 17.67% (n = 53). Presence of diabetes was an independent predictor of CAD (OR 1.98, 95% CI 1.07-3.67. P .02). No significant association was found between the presence of LAD and CAD in all subgroup comparisons. However, there was a suggestion of higher LAD among patients with known CAD compared with others.ConclusionsCAD is prevalent in patients with ischemic stroke. No definitive relationship was found between CAD and intracranial or extracranial LAD. Population based stratification tools are needed to further assess the need to detect subclinical CAD in patients with stroke.     

Proximal humeral reconstruction using nail cement spacer in primary and metastatic tumours of proximal humerus

Limb salvage surgery for malignant tumours of proximal humerus is an operative challenge, where the surgeon has to preserve elbow and hand functions and retain shoulder stability with as much function as possible. We treated 14 consecutive patients with primary malignant or isolated metastasis of proximal humerus with surgical resection and reconstruction by nail cement spacer. There were 8 females and 6 males, with a mean age of 28.92 years (range 16–51 years) and a mean follow-up of 30.14 months (range 12–52 months). The diagnosis was osteosarcoma in 8 patients, chondrosarcoma in 4 patients and metastasis from thyroid and breast carcinoma in 1 patient each. One of our patients had radial nerve neuropraxia, 1 developed inferior subluxation and 3 developed distant metastasis. Two patients died of disease and one developed local recurrence leading to forequarter amputation, leaving a total of 11 patients with functional extremities for assessment at the time of final follow-up which was done using the Musculoskeletal Tumour Society (MSTS) score. Though we were able to preserve the elbow, wrist and hand functions in all patients, the abductor mechanism, deltoid muscle and axillary nerve were not salvageable in any of cases. The mean MSTS score at the time of final follow-up was 19.09. Thus, proximal humeral reconstruction using nail cement spacer is a technical simple, cost-effective and reproducible procedure which makes it a reliable option in subset of patients where the functions around the shoulder cannot be preserved despite costlier prosthesis.     

Differential effects of fluoxetine and venlafaxine on memory recognition: possible mechanisms of action

Serotonin-specific reuptake inhibitors (SSRI) and serotonin-norepinephrine reuptake inhibitors (SNRI) are antidepressant drugs commonly used to treat a wide spectrum of mood disorders (Wong and Licinio, 2001). Although they have been clinically used for more than 50 years, the molecular and cellular basis for the action of SSRIs and SNRIs is not clear. Considering that the changes in gene expression involved in the action of antidepressant drugs on memory have not been identified, in this study we investigated the impact of chronic treatment with a SSRI (fluoxetine) and a SNRI (venlafaxine) on the mRNA expression of genes related to memory cascade in the mouse hippocampus, namely, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), nitric oxide synthase 1 (NOS1), neurotrophic tyrosine kinase receptor type 2 (TrKB), mitogen-activated protein kinases (MAPK/ERK) and serotonin transporter (SERT). Animals treated with fluoxetine 10 mg/Kg/day for 28 days showed a significant decrease in the percentage of time spent in the novel object recognition test (p≤0.005) and induced MAPK1/ERK2 down-regulation (p=0.005). Our results suggest that the effect on cognition could probably be explained by fluoxetine interference in the MAPK/ERK memory pathway. In contrast, chronic treatment with venlafaxine did not reduce MAPK1/ERK2 expression, suggesting that MAPK1/ERK2 down-regulation is not a common effect of all antidepressant drugs. Further studies are needed to examine the effect of chronic fluoxetine treatment on the ERK-CREB system, and to determine whether there is a causal relationship between the disruption of the ERK-CREB system and the effect of this antidepressant on memory performance.     

Mechanisms of Flushing Due to Niacin and Abolition of These Effects

There are many factors that increase the risk of cardiovascular disease, and a prominent factor among these is dyslipidemia. The following literature review focuses on the use of niacin therapy in order to treat dyslipidemia and how to control the associated niacin flush. The associated studies gathered are reviews and randomized control trials. They were obtained by using electronic searches. Certain keywords took precedence, and articles focusing on niacin therapy were chosen. Recent research has found promising insight into more effective prevention of the niacin-mediated flush through a selective antagonist for the prostaglandin D2 receptor, laropiprant. Aspirin (or NSAIDs) also provide some prevention for flushing, although recent studies have shown that it is not as effective as laropiprant. There is a need for further research in order to come to a clear conclusion regarding combined therapies of aspirin and laropiprant pretreatment, as well as exact dosage requirements.     

Basis for the preferential activation of cardiac sympathetic nerve activity in heart failure

In heart failure (HF), sympathetic nerve activity is increased. Measurements in HF patients of cardiac norepinephrine spillover, reflecting cardiac sympathetic nerve activity (CSNA), indicate that it is increased earlier and to a greater extent than sympathetic activity to other organs. This has important consequences because it worsens prognosis, provoking arrhythmias and sudden death. To elucidate the mechanisms responsible for the activation of CSNA in HF, we made simultaneous direct neural recordings of CSNA and renal SNA (RSNA) in two groups of conscious sheep: normal animals and animals in HF induced by chronic, rapid ventricular pacing. In normal animals, the level of activity, measured as burst incidence (bursts of pulse related activity/100 heart beats), was significantly lower for CSNA (30 ± 5%) than for RSNA (94 ± 2%). Furthermore, the resting level of CSNA, relative to its maximum achieved while baroreceptors were unloaded by reducing arterial pressure, was set at a much lower percentage than RSNA. In HF, burst incidence of CSNA increased from 30 to 91%, whereas burst incidence of RSNA remained unaltered at 95%. The sensitivity of the control of both CSNA and RSNA by the arterial baroreflex remained unchanged in HF. These data show that, in the normal state, the resting level of CSNA is set at a lower level than RSNA, but in HF, the resting levels of SNA to both organs are close to their maxima. This finding provides an explanation for the preferential increase in cardiac norepinephrine spillover observed in HF.