Determination of Non-Recrystallization Temperature for Niobium Microalloyed Steel.

In the present investigation, the non-recrystallization temperature (TNR) of niobium-microalloyed steel is determined to plan rolling schedules for obtaining the desired properties of steel. The value of TNR is based on both alloying elements and deformation parameters. In the literature, TNR equations have been developed and utilized. However, each equation has certain limitations which constrain its applicability. This study was completed using laboratory-grade low-carbon Nb-microalloyed steels designed to meet the API X-70 specification. Nb- microalloyed steel is processed by the melting and casting process, and the composition is found by optical emission spectroscopy (OES). Multiple-hit deformation tests were carried out on a Gleeble® 3500 system in the standard pocket-jaw configuration to determine TNR. Cuboidal specimens (10 (L) × 20 (W) × 20 (T) mm3) were taken for compression test (multiple-hit deformation tests) in gleeble. Microstructure evolutions were carried out by using OM (optical microscopy) and SEM (scanning electron microscopy). The value of TNR determined for 0.1 wt.% niobium bearing microalloyed steel is ~ 951 °C. Nb- microalloyed steel rolled at TNR produce partially recrystallized grain with ferrite nucleation. Hence, to verify the TNR value, a rolling process is applied with the finishing rolling temperature near TNR (~951 °C). The microstructure is also revealed in the pancake shape, which confirms TNR.

Activating autoantibodies to the ß1/2-adrenergic and M2 muscarinic receptors associate with atrial tachyarrhythmias in patients with hyperthyroidism.

We have previously demonstrated that activating autoantibodies to ß1-adrenergic receptor (ß1AR) and M2 muscarinic receptor (M2R) facilitate atrial fibrillation (AF) in patients with Graves' disease (GD). The objectives of this expanded study were to examine the prevalence of ß1AR, ß2AR, and M2R autoantibodies in hyperthyroidism subjects. Sera from 81 patients including 31 with GD and AF, 36 with GD and sinus rhythm, 9 with toxic multinodular goiter, 5 with subacute thyroiditis, and 10 control subjects were examined for these autoantibodies by ELISA. Sera from 20 ELISA-positive GD subjects, 10 with AF and 10 with sinus rhythm, were assayed for autoantibody bioactivity using cell-based bioassays. In patients with GD and AF, 45, 65, and 77 % were ELISA positive for ß1AR, M2R, and ß2AR autoantibodies, respectively. In patients with GD and sinus rhythm, 17, 39, and 75 % were ELISA positive for ß1AR, M2R, and ß2AR autoantibodies, respectively. ß1AR and M2R autoantibodies were co-present in 39 % of patients with GD and AF compared to 14 % in GD with sinus rhythm (p = 0.026). Patients with toxic multinodular goiter or subacute thyroiditis had a low prevalence of autoantibodies. The mean ß1AR and M2R autoantibody activity was elevated in both GD groups but higher in those with AF than those with sinus rhythm. ß2AR autoantibody activity was also increased in both groups. In conclusion, ß1AR, ß2AR, and M2R autoantibodies were elevated in GD. ß1AR and M2R autoantibodies appear to be related to concurrent AF, while ß2AR autoantibodies were equally prevalent in those with a sinus tachycardia and those with AF.

Autoimmune basis for postural tachycardia syndrome.

BACKGROUND: Patients with postural tachycardia syndrome (POTS) have exaggerated orthostatic tachycardia often following a viral illness, suggesting autoimmunity may play a pathophysiological role in POTS. We tested the hypothesis that they harbor functional autoantibodies to adrenergic receptors (AR). METHODS AND RESULTS: Fourteen POTS patients (7 each from 2 institutions) and 10 healthy subjects were examined for α1AR autoantibody-mediated contractility using a perfused rat cremaster arteriole assay. A receptor-transfected cell-based assay was used to detect the presence of ß1AR and ß2AR autoantibodies. Data were normalized and expressed as a percentage of baseline. The sera of all 14 POTS patients demonstrated significant arteriolar contractile activity (69±3% compared to 91±1% of baseline for healthy controls, P<0.001) when coexisting ß2AR dilative activity was blocked; and this was suppressed by α1AR blockade with prazosin. POTS sera acted as a partial α1AR antagonist significantly shifting phenylephrine contractility curves to the right. All POTS sera increased ß1AR activation (130±3% of baseline, P<0.01) and a subset had increased ß2AR activity versus healthy subjects. POTS sera shifted isoproterenol cAMP response curves to the left, consistent with enhanced ß1AR and ß2AR agonist activity. Autoantibody-positive POTS sera demonstrated specific binding to ß1AR, ß2AR, and α1AR in transfected cells. CONCLUSIONS: POTS patients have elevated α1AR autoantibodies exerting a partial peripheral antagonist effect resulting in a compensatory sympathoneural activation of α1AR for vasoconstriction and concurrent ßAR-mediated tachycardia. Coexisting ß1AR and ß2AR agonistic autoantibodies facilitate this tachycardia. These findings may explain the increased standing plasma norepinephrine and excessive tachycardia observed in many POTS patients.

Autoimmune mechanisms activating the angiotensin AT1 receptor in 'primary' aldosteronism.

CONTEXT: The mechanisms causing excessive aldosterone production and hypertension in primary aldosteronism (PA) are complex and often incompletely recognized. Autoantibodies to the angiotensin AT1 receptor (AT1R) have been reported in some PA patients with an aldosterone-producing adenoma but not with idiopathic adrenal hyperplasia. OBJECTIVE: We investigated whether these autoantibodies will activate AT1R and thereby potentially contribute to the pathophysiology of PA. DESIGN: AT1R autoantibody activity in sera and/or IgG purified from 13 biochemically confirmed PA patients was measured using AT1R-transfected cells, and their contractile effects were assayed using perfused rat cremaster arterioles. Aldosterone stimulation was measured in vitro using isolated human adrenal carcinoma (HAC15) adrenal cells. These data were compared with sera obtained from a group of normotensive control subjects who were expected to have negligible AT1R autoantibodies. RESULTS: Sera from each of the 13 PA patients significantly increased AT1R activation in AT1R-transfected cells compared with 20 control subjects, and this activity was inhibited by the selective AT1R blocker losartan. Sera and IgG purified from AT1R autoantibody-positive sera demonstrated significant vasoconstrictive effects in isolated rat cremaster arterioles and were blocked by losartan. Moreover, the AT1R autoantibody-positive IgG directly stimulated aldosterone production in the cultured adrenal cells and enhanced angiotensin-induced aldosterone production in these cells, and these effects were blocked by candesartan. CONCLUSIONS: These data support a probable pathophysiological role for AT1R autoantibodies in PA and thereby raise important etiological and therapeutic implications.

Laparoscopic trans-peritoneal pyelolithotomy in a pelvic kidney.

Urinary lithiasis is one of the most common and the oldest known afflictions of the urinary tract. The management of renal stones has undergone radical changes in recent years, the latest being the minimally invasive procedures like extra-corporeal shock wave lithotripsy and percutaneous nephrolithotomy, making the open surgical procedures relatively obsolete. However, there are situations where the above-mentioned minimally invasive procedures prove to be lacking in achieving the cure; laparoscopic pyelolithotomy caters to such group of patients, e.g. the presence of calculi in malrotated or malpositioned kidneys. Herein, we report a case of pelvic kidney with a large calculus managed by laparoscopic trans-peritoneal pyelolithotomy.

Agonistic autoantibodies as vasodilators in orthostatic hypotension: a new mechanism.

Agonistic autoantibodies to the ß-adrenergic and muscarinic receptors are a novel investigative and therapeutic target for certain orthostatic disorders. We have identified the presence of autoantibodies to ß2-adrenergic and/or M3 muscarinic receptors by ELISA in 75% (15 of 20) of patients with significant orthostatic hypotension. Purified serum IgG from all 20 of the patients and 10 healthy control subjects were examined in a receptor-transfected cell-based cAMP assay for ß2 receptor activation and ß-arrestin assay for M3 receptor activation. There was a significant increase in IgG-induced activation of ß2 and M3 receptors in the patient group compared with controls. A dose response was observed for both IgG activation of ß2 and M3 receptors and inhibition of their activation with the nonselective ß blocker propranolol and muscarinic blocker atropine. The antibody effects on ß2 and/or M3 (via production of NO) receptor-mediated vasodilation were studied in a rat cremaster resistance arteriole assay. Infusion of IgG from patients with documented ß2 and/or M3 receptor agonistic activity produced a dose-dependent vasodilation. Sequential addition of the ß-blocker propranolol and the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester partially inhibited IgG-induced vasodilation (percentage of maximal dilatory response: from 57.7±10.4 to 35.3±4.6 and 24.3±5.8, respectively; P<0.01; n=3), indicating that antibody activation of vascular ß2 and/or M3 receptors may contribute to systemic vasodilation. These data support the concept that circulating agonistic autoantibodies serve as vasodilators and may cause or exacerbate orthostatic hypotension.

Autoantibody activation of beta-adrenergic and muscarinic receptors contributes to an "autoimmune" orthostatic hypotension.

BACKGROUND: Orthostatic hypotension (OH) is characterized by an abnormal autonomic response to upright posture. Activating autoantibodies to ß1/2-adrenergic (AAß1/2AR) and M2/3 muscarinic receptors (AAM2/3R) produce vasodilative changes in the vasculature that may contribute to OH. METHODS: Immunoglobulin (Ig)G from 6 patients with idiopathic OH harboring autoantibodies and from 10 healthy control subjects were examined for: 1) ß1AR and M2R activity with a perfused Purkinje fiber assay and PKA assay in H9c2 cells and 2) vasodilator ß2AR and M3R activity using a pressurized cremaster resistance arteriole assay. Changes in IgG activity with and without propranolol, atropine, and L-NAME were used to estimate AAßAR, AAM2R, and AAM3R activation of their respective functions. RESULTS: All six patients had elevated enzyme-linked immunosorbent assay titers to at least one of the receptors compared with controls. ßAR-mediated contractility activity and M2R activity were increased in five of the six patients. IgG from all six patients produced a direct vasodilator effect on cremaster arterioles. ßAR and nitric oxide synthase blockade led to near normalization of IgG-induced vasodilation. CONCLUSION: AAß1/2AR and AAM2/3R are present in some patients with idiopathic OH compatible with an in vivo effect. These autoantibodies and their cardiovascular effects provide new mechanistic insights into the pathophysiology of OH.

Laparoscopic trans-mesocolic pyeloplasty in children: initial experience from a center in India.

The aim of the present study is to report our experience with laparoscopic pyeloplasty via trans-mesocolic approach in children with left pelvi-ureteric junction (PUJ) obstruction. Between May 2007 and May 2008, 12 children aged between five and 16 years, with documented PUJ obstruction on the left side, underwent laparoscopic pyeloplasty via trans-mesocolic approach. The outcome was assessed by post-operative isotope renal scan. The mean age of the study patients was eight years, ranging between five and 16 years. There were five males and seven females in the study. All children underwent Anderson Hynes Pyeloplasty by a single surgeon. All cases were stented with a JJ stent for a period of six weeks post-operatively. The procedures were completed successfully in all patients without need for conversion to open pyeloplasty in any patient. The mean operative time was 95 min, with a range of 80-140 min. The average blood loss was 57 mL. The mean hospital stay was 3.5 days with a range of 2.5 to six days. All children returned back to school within nine days following surgery. The mean follow-up period was 12 months (range, nine to 14 months). Eleven of the patients were completely asymptomatic, while one reported mild flank pain. All children underwent renal scans and renal ultrasound three months after stent removal. Ten had improved function on the scan while in one patient, the function remained the same and, in another, it showed obstructed response to diuretic, although the symptoms had improved. In all the cases, renal ultrasound showed a decrease in the severity of hydronephrosis by at least one degree. These results confirm that laparoscopic pyeloplasty by trans-mesocolic approach in children for left-sided PUJ obstruction is safe and feasible.

Use of pneumatic lithotripsy for managing difficult CBD calculi.

INTRODUCTION: About 7-12% of patients who harbor gallbladder calculi concomitant common bile duct (CBD) calculi are present. The treatment of gallbladder calculi has standardized in the form of laparoscopic cholecystectomy but management of CBD calculi is still evolving. Endoscopic removal of CBD calculi <2 cm in diameter is successful in 90-100% of cases but patients harboring stones >2 cm in diameter high failure rates can be seen. Traditionally, laparoscopically one can achieve success rate comparable to endoscopic surgery but large and impacted calculi may cause failures. If one uses pneumatic lithotripsy during laparoscopic management of CBD calculi one can achieve 100% stone clearance irrespective of size, degree of hardness and impaction. This study evaluates the feasibility of using pneumatic lithotripsy for CBD calculi. To our knowledge this is the 1st reported series of using pneumatic lithotripsy for CBD calculi. MATERIAL AND METHODS: From June 2002 to June 2010 96 laparoscopic CBD explorations (LCBDE) were done for CBD calculi. Patients having choledocholithiasis with CBD diameter of >10 mm were taken for LCBDE while in patients with CBD diameter of <10 mm were referred for endoscopic clearance. Additionally ERCP failure cases were also subjected to LCBDE. Rigid nephroscope was used for LCBDE and usually calculi were removed by forceps only. In patients having large, hard &/or impacted calculi pneumatic lithotripsy were used for fragmentation. RESULTS: Out of the 96 patients in 12 (12.5%) cases pneumatic lithotripsy was used for stone fragmentation. Out of these 12 cases 5 (41.6%) were ERCP failure cases. At a mean hospital stay of 2.5 days 100% stone clearance was achieved in all cases with no perioperative complication. CONCLUSION: The present study shows how successfully pneumatic lithotripsy can be used to fragment large, hard &/or impacted CBD calculi. Pneumatic lithotripsy being user friendly easily available can reliably fragment CBD calculi in one session.

Retroperitoneal laparoscopic ureterolithotomy--a single centre 10 year experience.

INTRODUCTION: The management of ureteric stones has standardized with the introduction of ureteroscopy (URS), shock wave lithotripsy(SWL) and HO:YAG laser. But still one may need to use laparoscopic ureterolithotomy for failed URS/SWL cases or as a primary procedure for large impacted stones. At centers which do not have access to expensive equipment needed in URS and SWL, laparoscopic ureterolithotomy may be used as a primary procedure. The aim of this article is to share our 10 year long experience and the lessons learnt from performing retroperitoneal laparoscopic ureterolithotomy (RLU) which we believe is the better route than transperitoneal one. METHODS: From January 2000 to January 2010, 820 cases of ureteric stones were managed at our centre. RLU was performed for 126 cases. Most common indication for RLU was as a primary procedure for large impacted upper or mid ureteric stones 86(68.25%) followed by failed URS in 28(22.23%) and failed SWL in 12(9.52%) cases. RESULTS: With a mean operative time of 88(45-120) min RLU was successful in 123(97.6%) cases. There was no major intra or postoperative complication. Most common complication of the procedure was the inadvertent peritoneotomy 15(11.9%). Mean hospital stay was 2.8(2-13) days and there were 3(2.38%) cases of prolonged urinary drainage which were managed conservatively. CONCLUSION: RLU is a very effective minimally invasive modality of treating ureteral calculi. Unlike URS this procedure can give 100% stone clearance in one session. Its role in advanced urological centers is primarily as a salvage procedure for failed URS/SWL but in developing nations which usually do not have access to URS and SWL RLU can be used as a primary procedure for managing upper and mid ureteric stones with excellent results and with minimal resources.

Thrombosis of the dorsal vein of the penis (Mondor's Disease): A case report and review of the literature.

Superficial thrombophlebitis of the dorsal vein of the penis (penile Mondor's Disease) is an important clinical diagnosis that every family practitioner should be able to recognize. Dorsal vein thrombosis is a rare disease with pain and induration of the dorsal part of the penis. The possible causes comprise traumatism, neoplasms, excessive sexual activity, or abstinence. The differential diagnosis must be established with Sclerotizing lymphangitis and peyronies disease and doppler ultrasound is the imaging diagnostic technique of choice. Proper diagnosis and consequent reassurance can help to dissipate the anxiety typically experienced by the patients with this disease. We describe the symptoms, diagnosis, and treatment of the superficial thrombophlebitis of the dorsal vein of the penis.

Retroperitoneal versus transperitoneal laparoscopic pyeloplasty: our experience.

OBJECTIVE: Laparoscopic pyeloplasty, which has been quoted to have a success rate equivalent to open pyeloplasty for ureteropelvic junction obstruction (UPJO), can be performed transperitoneally and retroperitoneally. The aim of the present study is to report our experience with these 2 routes of laparoscopic pyeloplasty and to further improve our understanding of the merits and demerits of these 2 routes. PATIENTS AND METHODS: A total of 47 laparoscopic pyeloplasties were performed at our center from June 2000 to August 2009. Twelve pyeloplasties were performed transperitoneally and 35 retroperitoneally. RESULTS: In the retroperitoneal group, we had a success rate of 91.5% after a mean follow-up of 22 months, and in the transperitoneal group, we had a success rate of 91.7% after a mean follow-up of 48 months. The mean operative time was 156 min in the retroperitoneal group and 195 min in the transperitoneal group. CONCLUSION: This study shows a success rate comparable with open pyeloplasty and favors the retroperitoneal route with a shorter operative time, less dissection needed, a higher sensitivity of detecting crossing vessels, a decreased risk in visceral injury and an early start of oral feeds.

Laparoscopic and open incisional hernia repair using polypropylene mesh - a comparative single centre study.

INTRODUCTION: Repair of incisional hernias continues to be a challenging surgical procedure for general surgeons. Currently open mesh repair and laparoscopic repair are the two main options available for general surgeon for managing this complication. Laparoscopic repair though offers all the advantages of minimal access surgery but is a costly procedure especially due to the use of costly composite mesh. The present study is aimed to compare the open and laparoscopic repair of incisional hernia and at the same time evaluate the safety and feasibility of using comparatively cheaper polypropylene mesh. METHODS: Between December 2005 and December 2009 80 patients underwent incisional hernia repair, 40 open repairs and 40 laparoscopic repair. The results of the two procedures were compared with a mean follow up of 26 months for open repair and 28 months for laparoscopic repair. RESULTS: Obstetrical or gynecological procedure was the most common index surgery leading to incisional hernia and lower midline incision was the most common site of hernia. The mean defect size in open repair group was 55.2 cm(2) and 62.2 cm(2) in laparoscopic repair group. Polypropylene mesh was used in all cases. We had 1(2.5%) major complication of enterotomy and 1(2.5%) conversion in laparoscopic repair group. Postoperative complications were most commonly seen in open repair group 10(25%) and 2(5%) in laparoscopic repair group. Mean hospital stay in open repair group is 4.33 days and 1.53 days in laparoscopic repair group. We had 1(2.5%) recurrence in both groups. CONCLUSION: Laparoscopic repair of incisional hernia is a much better procedure for curing incisional hernia as compared to open mesh repair and additionally intraperitoneal use of polypropylene mesh was not associated with any significant complication.

Retroperitoneal laparoscopy for the management of renal hydatid cyst.

Hydatid disease is one of the common parasitic afflictions seen in sheep rearing areas of world, with certain areas in northern India showing a very high incidence. It is caused by the larval/cyst stage of Echinococcus granulosus, in which humans are an intermediate host. The cysts are located in liver 75% times, lungs 15%, other organs 10%. Isolated involvement of kidneys is rare and forms 2-4% of cases. The treatment usually requires some form of intervention ranging from minimally invasive percutaneous aspiration techniques to laparoscopic and the maximally invasive, open techniques. Herein, we describe two cases of isolated renal hydatid cysts that were treated successfully by retroperitoneal laparoscopic approach to prevent the soiling of peritoneal cavity. One of the cases had a preoperative diagnosis of simple renal cyst. No complications occurred at peroperative and postoperative periods. The patients were given 3 cycles of Albendazole (10 mg/kg in two divided doses), each for a period of four weeks followed by a weeks rest. The patients are under strict follow-up and no recurrence has been documented yet.

Total renal replacement lipomatosis.

Renal replacement lipomatosis can be defined as the proliferation of fibrofatty tissue which subsequently replaces the renal parenchyma. It is usually unilateral and occurs as a result of severe atrophy or destruction of the renal parenchyma, mostly due to a calculus with secondary proliferation of renal sinus, renal hilus, and perirenal fatty tissue to a variable extent. There may be moderate replacement of renal tissue by fat as in renal sinus lipomatosis or in severe cases the whole of the renal parenchyma may be replaced by fat and is referred to as renal replacement lipomatosis. Herein we report a case of total renal replacement lipomatosis. The possible pathogenic mechanisms and the treatment are also discussed.

Use of rigid nephroscope for laparoscopic common bile duct exploration-a single-center experience.

BACKGROUND: Increasingly, laparoscopic biliary surgeons are undertaking laparoscopic cholecystectomy and laparoscopic common bile duct exploration for patients with cholelithiasis and choledocholithiasis. In laparoscopic common bile duct exploration a flexible choledochoscope is ordinarily used, and with this instrument the surgeon usually fails to remove large impacted stones. In contrast with use of a rigid nephroscope it is possible to remove all common bile duct stones irrespective of size and degree of impaction. The present study evaluates the efficiency of rigid nephroscope for managing common bile duct stones laparoscopically. METHODS: In the present study laparoscopic common bile duct exploration for stones was performed in 80 patients via standard laparoscopic cholecystectomy port sites. Patients with a common bile duct diameter >10 mm were included in this study. The rigid nephroscope was passed through the epigastric port and negotiated into the common bile duct through a choledochotomy. Stones were removed with graspers. Large hard stones were fragmented by pneumatic lithotripsy. RESULTS: Of the 80 patients treated in this manner, 72 (90%) had multiple common bile duct calculi, and 8 (10%) had a solitary common bile duct calculus. Mean common bile duct diameter was 15.3 mm (range: 10-37 mm). Conversion to open common bile duct exploration was necessary in 1 case (1.25%) because of difficult dissection secondary to extensive dense adhesions. In 7 patients (8.75%) a pneumatic lithotripter was used to fragment stones. Choledochotomy was managed by placing a T-tube in 21 (26.25%) patients, by effecting primary closure in 58 (72.5%) patients, and by choledochoduodenostomy in 1 (1.25%) patient. The mean operative time in this series was 83 min (range: 53-135 min). The mean postoperative hospital stay was 4.2 days (range: 3-19 days). One patient (1.25%) developed cholangitis 5 months after laparoscopic common bile duct exploration; the cause was a residual common bile duct stone. CONCLUSIONS: A rigid nephroscope can be used for managing all types of common bile duct calculi irrespective of site, size, composition, or degree of impaction. Its use can be expected to become the standard for laparoscopic common bile duct exploration, especially for removing large calculi from a dilated common bile duct.

Retroperitoneal laparoscopic uretero-pyelostomy for symptomatic yo-yo reflux.

Incomplete ureteric duplication is usually an incidental finding. However, this condition may occasionally be symptomatic and warrant surgical correction. Various surgical procedures are used to treat this condition with varying degrees of success. We present the case report of a 21-year-old female who had right-sided symptomatic incomplete ureteric duplication and was managed by retroperitoneal laparoscopic ureteropyelostomy. To our knowledge, this is the first reported case of such a procedure.

Innovative technique for ureteral stenting during retroperitoneal laparoscopic ureterolithotomy.

Large calculi in the upper and mid ureter are best managed by laparoscopic ureterolithotomy. Stenting after laparoscopic ureterolithotomy is difficult because of the curls and pliability of the double-J stent. To make the procedure easy, we have devised a double-J stent, closed at both ends, that is threaded on a guidewire, the length of which is 1 cm greater than the stent. The guidewire is passed from the sideholes in the stent, leaving 1 or 2 cm of the guidewire outside. This guidewire makes the stent taut so that it is easily negotiated up and down the ureter. After the stone has been extracted by incising the ureter, the straightened stent on the guidewire is passed in the retroperitoneal space through a 5-mm port. The stent is passed down the ureter into the bladder first and then up the ureter to the renal pelvis. The portion of the guidewire lying outside the stent is positioned at the site of ureterolithotomy. The guidewire is pulled out with a grasper after insertion of stent, and the two ends of the stent coil up in the bladder and the kidney. This innovative technique with the modified stent and guidewire has made stenting during laparoscopic ureterolithotomy easy and saves precious time.