Effect of stenosis and dilatation on the hemodynamic parameters associated with left coronary artery.

BACKGROUND AND OBJECTIVE: The main objective of the work is to examine the curvature effects of stenosis/dilatation region pertaining to left coronary artery. The hemodymamic features during the cardiac cycle is thoroughly examined. METHODS: A numerical fluid structure interaction model incorporating multi- layered elastic artery wall, non-Newtonian blood viscosity and pulsating boundary conditions is developed. The composite arterial wall consists of a thin layer tunica intima, atheroma and a thick wall. Higher stiffness of atheroma is captured by using higher Young's modulus. The CFD and FSI models are validated with available experimental and analytical data. Computations are done with five different non-Newtonian models and arterial wall with various elasticity levels. The local and time averaged WSS, velocity contours downstream of stenosis, wall pressure and pressure drop during various phases of cardiac cycle are provided in detail. RESULTS: The influence of non-Newtonian effects of blood viscosity is found to be significant especially at stenosis regions. The flexible wall caused wall deformation and the associated flow and pressure wave propagation affecting WSS and pressure drop compared to the rigid wall. Flow recirculation is noticed at stenosis downstream locations and its strength increases with increased severity of the stenosis. A stenosis is characterised by a sudden drop in wall pressure and a slower two stage recovery during peak velocity periods of the cardiac cycle. CONCLUSIONS: The pressure drop, local WSS at stenosis centre, and radial velocity increase are significantly higher for stenosis cases and the effect is severe during peak diastole. The variation in hemodynamic parameters is found to be less significant for dilatation. Significantly lower WSS is noticed for the recirculation regions downstream of stenosis which can enhance the tendency for monocytes to attach to the endothelium. The radius of curvature of the stenosis is found to be the most sensitive parameter affecting the hemodynamic characteristics rather than the detailed geometry of the stenosis. The main effect of variation of artery wall stiffness is noted at recirculation regions present downstream of stenosis. The results from the study may be useful for predicting wall shear stress signatures associated with stenosis/dilatation changes and the management of specific cases.

Occurrence of 210Po in periwinkle (Littorina undulata, Gray, 1839) collected from Kudankulam (Gulf of Mannar (GOM), Southeast coast of India).

Polonium-210 activity concentration was analysed in the whole body tissue of periwinkle Littorina undulata collected from intertidal rocky shore along Kudankulam coast. We carried out the study for a period of 12 months (2011-2012) focusing on three seasons. (210)Po was found non-uniformly distributed among the periwinkles depending on the allometry. The (210)Po accumulation showed a significant difference between seasons (p<0.05). Smaller sized winkles registered higher activity of (210)Po compared to larger ones (p<0.05). The overall activity range of (210)Po varied from 13.5 to 58.9 Bq/kg (wet). The activity of (210)Po was also quantified in seawater and intertidal sediments to calculate the biological concentration factor (BCF) and radiation dose rate. The dose rate to the winkles was performed using ERICA Assessment Tool and it was within the prescribed limit. The intake of (210)Po through periwinkles delivered an effective dose in the range of 2.2-9.6 µSv/y to human beings.

Medial joint line bone bruising at MRI complicating acute ankle inversion injury: what is its clinical significance?

AIM: To assess the incidence and clinical significance of medial joint line bone bruising following acute ankle inversion injury. MATERIALS AND METHODS: Forty-five patients who underwent ankle magnetic resonance imaging (MRI) within 2 weeks of acute ankle inversion injury were included in this prospective study. Integrity of the lateral collateral ligament complex, presence of medial joint line bone bruising, tibio-talar joint effusion, and soft-tissue swelling were documented. Clinical follow-up at 6 months was carried out to determine the impact of injury on length of time out of work, delay in return to normal walking, delay in return to sports activity, and persistence of medial joint line pain. RESULTS: Thirty-seven patients had tears of the anterior talofibular ligament (ATFL). Twenty-six patients had medial joint line bone bruising with altered marrow signal at the medial aspect of the talus and congruent surface of the medial malleolus. A complete ATFL tear was seen in 92% of the patients with medial joint line bone bruising (p = 0.05). Patients with an ATFL tear and medial joint line bone bruising had a longer delay in return to normal walking (p = 0.0002), longer delay in return to sports activity (p = 0.0001), and persistent medial joint line pain (p = 0.0003). There was no statistically significant difference in outcome for the eight patients without ATFL tears. CONCLUSION: Medial joint line bone bruising following an acute ankle inversion injury was significantly associated with a complete ATFL tear, longer delay in the return to normal walking and sports activity, as well as persistent medial joint line pain. Its presence should prompt detailed assessment of the lateral collateral ligament complex, particularly the ATFL.

Audit on breast ultrasound in women under 25 years.

BACKGROUND: Women younger than 30 years with a focal breast finding have a low incidence of malignancy. Targeted ultrasound is an accurate primary imaging test. MATERIALS AND METHODS: All breast ultrasounds performed from July 1, 2011 to September 30, 2011 were reviewed. All ultrasounds in patients under 25 years were reviewed with regard to indication, imaging findings, and pathology results. RESULTS: Over a 3-month period, 855 breast ultrasounds were performed; 4.1 % breast ultrasounds were performed in a patient under 25 years. Twenty patients had imaging features consistent with a fibroadenoma. Pathology confirmed the diagnosis of fibroadenomas in 15 of the patients. Five patients did not have biopsies performed due to young age or presence of bilateral fibroadenoma. CONCLUSION: A breast nodule in a patient under the age of 25 years with benign clinical findings and imaging features consistent with a fibroadenoma does not require biopsy.

Three Tesla MRI for the diagnosis of meniscal and anterior cruciate ligament pathology: a comparison to arthroscopic findings.

AIM: To assess the accuracy of 3T magnetic resonance imaging (MRI) in the evaluation of meniscal and anterior cruciate ligament (ACL) injury. MATERIALS AND METHODS: Sixty-one consecutive patients were identified who were referred for evaluation of suspected intra-articular pathology with a 3T MRI and who, subsequently, underwent an arthroscopic procedure of the knee were included for the study. Two musculoskeletal radiologists interpreted the images. The sensitivity, specificity, positive predictive value, and negative predictive value were then calculated for the MRI versus the arthroscopic findings as a reference standard. RESULTS: The sensitivity and specificity for the overall detection of meniscal tears in this study was 84 and 93%, respectively. The results for the medial meniscus separately were 91 and 93% and for the lateral 77 and 93%. The evaluation of ACL integrity was 100% sensitive and specific. The meniscal tear type was correctly identified in 75% of cases and its location in 94%. CONCLUSION: This study demonstrates good results of 3T MRI in the evaluation of the injured knee. Caution should still be given to the interpretation on MRI of a lateral meniscus tear, and it is suggested that the standard diagnostic criteria of high signal reaching the articular surface on two consecutive image sections be adhered to even at these higher field strengths.

Endoscopic ultrasound-guided biopsies of pancreatic masses: comparison between fine needle aspirations and needle core biopsies.

Endoscopic ultrasound-guided fine needle aspiration (EUS-guided FNA) is a highly sensitive and specific method for diagnosing pancreatic masses. Alternatively, EUS-guided needle core biopsies (NCB) have also been introduced. We sought to determine efficacies of pancreatic EUS-guided FNAs and NCBs. Records of consecutive EUS-guided FNAs received over a 24-mo-period were reviewed. Cases with concurrent NCBs were selected for the study. The diagnoses from the two modalities were compared and designated concordant (CC) or discordant (DC). Of 252 cases, 52 had concurrent NCBs. The final diagnoses included primary and secondary tumors. Of the 52 cases, 29/52 (55.8%) were CC and 23/52 (44.2%) were DC. The sensitivities for FNAs and NCBs were 95.0% and 67.6%, respectively. Both modalities were 100% specific. Direct comparison between EUS-guided FNAs and NCBs demonstrated that the former are more sensitive for diagnosing pancreatic neoplasms, both primaries and metastases. There was no correlation between CC/DC cases and type of neoplasm.

Utility of CD138 (syndecan-1) in distinguishing carcinomas from mesotheliomas.

CD138 (Syndecan-1) is a transmembrane heparan sulfate proteoglycan present on the surface of plasma cells and epithelial cells. CD138 is also expressed in some hematopoietic neoplasms and has recently been observed in carcinomas. We characterized CD138 expression in cell-block preparations of fluids/effusions, focusing on the distinction between carcinoma and mesothelioma. One hundred formalin-fixed, paraffin-embedded cell-block sections of fluids/effusions consisting of 58 metastatic carcinomas, 24 mesotheliomas, 11 reactive mesothelial cell proliferations, 3 lymphomas, 3 metastatic sarcomas, and 1 metastatic melanoma were stained with a monoclonal antibody against CD138. CD138 staining was observed in 32/58 (55%) metastatic carcinomas and 2/24 (8%) mesotheliomas; all reactive mesothelial cells, lymphomas, sarcomas, and melanoma were negative. CD138 is a highly specific marker in the differential diagnosis of carcinoma vs. mesothelioma. Distinct membranous staining without background staining of most inflammatory cells makes CD138 an ideal marker for cell-block preparations of fluids/effusions. It should be an integral component of the epithelial-mesothelial antibody panel.

Paraplegia secondary to fracture-subluxation of the thoracic spine sustained playing rugby union football.

Fractures of the spinal column during rugby matches of all codes are rare but catastrophic, especially when associated with spinal cord injury. The cervical spine is vulnerable during trauma to the head and neck in contact sports. Spinal injuries reported during rugby matches have almost exclusively involved the cervical region, often with neurological sequelae. This is the first reported case of paraplegia caused by a fracture-dislocation of the thoracic spine resulting from a low velocity rugby union injury.

Antiapoptotic Cdc42 mutants are potent activators of cellular transformation.

Cdc42 is a small GTP-binding protein which has been implicated in a number of cellular activities, including cell morphology, motility, cell-cycle progression, and malignant transformation. While GTPase-defective forms of Cdc42 inhibit cell growth, a mutation [Cdc42(F28L)] that allows the constitutive exchange of GDP for GTP and is GTPase-competent induces cellular transformation. These results suggest that Cdc42 must cycle between its GTP- and GDP-bound states to stimulate cell growth. In attempting to design Cdc42 molecules with more potent transforming activity, we set out to generate other types of Cdc42 mutants capable of constitutive GDP-GTP exchange. Here, we describe one such mutant, generated by changing a conserved aspartic acid residue at position 118 to an asparagine. The Cdc42(D118N) protein exchanges GDP for GTP more rapidly than wild-type Cdc42, but significantly more slowly than the Cdc42(F28L) mutant. Despite its slower rate of activation, the Cdc42(D118N) mutant is more potent at inducing cellular transformation than the Cdc42(F28L) protein, and causes a significant loss in actin stress fibers, reminiscent of what is observed with fibroblasts transformed by oncogenic Ras mutants. Effector-loop mutations made within the D118N background inhibit Cdc42-induced transformation and Cdc42-mediated antiapoptotic (survival) activity to similar extents. In addition, mutating aspartic acid 121 (to asparagine), which forms part of a caspase cleavage site (DLRD, residues 118-121 of Cdc42), in combination with the F28L mutation generates a Cdc42 molecule [Cdc42(F28L/D121N)] with transforming activity significantly stronger than that of Cdc42(F28L). Thus, mutations that combine some capacity for cycling between the GTP- and GDP-bound states with increased survival against apoptotic signals yield Cdc42 molecules with the maximum capability for inducing cellular transformation.

In vitro fertilization following natural cycles in poor responders.

This prospective study was designed to examine the feasibility of natural cycle in vitro fertilization (IVF) in poor responders, and the clinical factors that may predict successful outcome. Twenty-two poor responders underwent IVF treatment with 44 unstimulated cycles. The results of the natural cycles were compared with those of the 55 low-response stimulated cycles of these patients during the 12 months prior to the study. Eighteen (82%) patients had at least one oocyte retrieved, while nine (41%) had at least one cycle with embryo transfer. Two (9%) patients each gave birth to a healthy term baby. These results are comparable with those of the stimulated cycles. Serum early follicular follicle stimulating hormone (FSH) level was found to be the only reliable predictor of oocyte recovery and overall outcome in each specific natural cycle. However, because of great variability in basal FSH levels among different cycles of the same patient, this is not a reliable predictor of outcome in future cycles. We conclude that poor responders are a unique group of patients who may benefit from natural-cycle IVF treatment.

Digital chest radiography with a selenium-based flat-panel detector versus a storage phosphor system: comparison of soft-copy images.

OBJECTIVE: We compared the soft-copy images produced by a digital chest radiography system that uses a flat-panel X-ray detector based on amorphous selenium with images produced by a storage phosphor radiography system for the visualization of anatomic regions of the chest. MATERIALS AND METHODS: Two chest radiologists and two residents analyzed 46 pairs of posteroanterior chest radiographs on high-resolution video monitors (2560 x 2048 x 8 bits). In each pair, one radiograph was obtained with a storage phosphor radiography system, and the other radiograph was obtained with a selenium-based flat-panel detector radiography system. Each pair of radiographs was obtained at the same exposure settings. The interpreter rated the visibility and radiographic quality of 11 different anatomic regions. Each pair of images was ranked on a five-point scale (1 = prefer image A, 3 = no preference, 5 = prefer image B) for preference of technique. Statistical significance of preference was determined using the Wilcoxon's signed rank test. RESULTS: The interpreters had a statistically significant preference for the selenium-based radiography system in six (unobscured lung, hilum, rib, minor fissure, heart border, and overall appearance) of 11 anatomic regions (p<0.001) and for the storage phosphor system in two regions (proximal airway and thoracic spine) (p<0.05). Chest radiologists strongly preferred selenium-based images in eight regions, and they did not prefer storage phosphor images in any region. CONCLUSION: The soft-copy images produced by the selenium-based radiography system were perceived as equal or superior to those produced by the storage phosphor system in most but not all anatomic regions.

Effects of gonadotrophin-releasing hormone agonists on human ovarian steroid secretion in vivo and in vitro-results of a prospective, randomized in-vitro fertilization study.

The aim of this prospective randomized study was to compare the effects of two gonadotrophin-releasing hormone (GnRH) agonists, buserelin and triptorelin, on human ovarian follicular steroidogenesis, oocyte fertilization and IVF treatment outcome. Ovulatory, healthy women undergoing IVF were treated either with human menopausal gonadotrophin (HMG) alone or with HMG and one of the two GnRH agonists. Serum and follicular fluid hormonal concentrations and cultures of luteinizing granulosa cells obtained during follicular aspiration were analysed. GnRH agonist treatment significantly affected steroidogenesis both in serum and follicular fluid. In follicular fluid, progesterone and oestradiol concentrations were significantly elevated while testosterone concentrations were significantly lower in the triptorelin group. The ratios of testosterone/progesterone, oestradiol/progesterone but not oestradiol/testosterone concentrations were significantly affected by GnRH agonist administration. Similarly, the steroidogenic activity of luteinizing granulosa cells in vitro was significantly decreased in women treated with GnRH agonists. Women treated with GnRH agonists had significantly more fertilized oocytes and cleaving embryos. The results indicate a marked effect of GnRH agonists on the pattern of ovarian follicular steroidogenesis that cannot be explained solely by changes in gonadotrophin concentrations.

Cortisol concentrations in follicular fluid of 'low responder' patients.

The study was undertaken to examine any differences existing in total cortisol concentrations in the follicular fluid (FF) of pre-ruptured follicles between 'low responder' patients (group 1, n = 20) and 'good responder' patients (group 2, n = 15). The groups were defined according to how many oocytes had been retrieved during the previous in-vitro fertilization procedure (group 1: three or fewer; group 2: more than three) and total oestradiol concentration at previous in-vitro fertilization (IVF) (group 1: < or = 500 pg/ml; group 2: > 500 pg/ml). All patients were aged 36-43 years (group 1 mean +/- SD: 38.2 +/- 4.7; group 2: 32.1 +/- 3.8 years) and were diagnosed with tubal or unexplained infertility. The total FF cortisol concentrations obtained in conjunction with an IVF procedure were assayed and related to oocyte fertilization. Follicular fluid was analysed for total cortisol content. Only follicles between 19 and 20 mm diameter were analysed in both groups. After aspiration of blood-free FF, total cortisol concentrations were measured by radioimmunoassay, designed for the quantitative measurement of cortisol, and related to oocyte fertilization. Total cortisol concentration in FF from fertilized oocytes was 9.7 +/- 0.6 microg/ml (mean +/- SD) in group 1 compared to 9.2 +/- 4.4 microg/ml in group 2 (not statistically significant). Total cortisol concentrations were not associated with oocyte fertilization and no difference between the groups was found in total cortisol concentrations in the FF of unfertilized oocytes or empty follicles.

[Microcirculatory disturbances in normotensive stage of endotoxin shock].

Red blood cell (RBC) deformability is necessary for maintenance of normal oxygenation in microcirculation. To evaluate oxygen utilization in the early stage of endotoxin shock, we observed RBCs from a rheological point of view in mesenteric microcirculation in rats. Endotoxin shock was induced by Shwaltzman reaction. The velocity of RBC decreased from 1.33 mm.sec-1 to 0.55 mm.sec-1 at 60 min after the provoking injection. RBC could not change its shape in capillaries. In contrast, the mean blood pressure remained at 110 mmHg throughout this observation. In hemorrhagic shock the deformability of RBC in capillaries was not impaired even though mean blood pressure decreased to 43 mmHg. In vitro, we examined the index of RBC deformability with or without endotoxin by the modified Reid's method. The index was decreased significantly by endotoxin. We conclude that impaired deformability of RBC may be a factor of insufficient oxygen utilization in the early stage of endotoxin shock.

[The effects of prostaglandin E1 infusion on the viscosity and pH of gastric fluid during general anesthesia].

We studied the protective effect of prostaglandin E1 (PGE1)-induced hypotensive anesthesia on gastric mucosa in 30 elective surgical patients. Three groups, each composed of 10 patients, received PGE1, nitroglycerin or none during general anesthesia. Then we measured the viscosity and pH of gastric fluid continuously in each group. In the PGE1 group the viscosity and pH increased significantly and rapidly (P less than 0.05) as compared with the other groups. This suggests that PGE1 offers prophylactic effect against postoperative acute gastric mucosal lesion (AGML).