Does increased postural threat lead to more conscious control of posture?

Although it is well established that postural threat modifies postural control, little is known regarding the underlying mechanism(s) responsible for these changes. It is possible that changes in postural control under conditions of elevated postural threat result from a shift to a more conscious control of posture. The purpose of this study was to determine the influence of elevated postural threat on conscious control of posture and to determine the relationship between conscious control and postural control measures. Forty-eight healthy young adults stood on a force plate at two different surface heights: ground level (LOW) and 3.2-m above ground level (HIGH). Centre of pressure measures calculated in the anterior-posterior (AP) direction were mean position (AP-MP), root mean square (AP-RMS) and mean power frequency (AP-MPF). A modified state-specific version of the Movement Specific Reinvestment Scale was used to measure conscious motor processing (CMP) and movement self-consciousness (MSC). Balance confidence, fear of falling, perceived stability, and perceived and actual anxiety indicators were also collected. A significant effect of postural threat was found for movement reinvestment as participants reported more conscious control and a greater concern about their posture at the HIGH height. Significant correlations between CMP and MSC with AP-MP were observed as participants who consciously controlled and were more concerned for their posture leaned further away from the platform edge. It is possible that changes in movement reinvestment can influence specific aspects of posture (leaning) but other aspects may be immune to these changes (amplitude and frequency).

Cognition and behavior in children with benign epilepsy with centrotemporal spikes (BECTS).

Characteristics of cognitive deficits in benign childhood epilepsy with centrotemporal spikes (BECTS) remain unclear. The authors screened 200 BECTS children presenting for a clinical trial, finding relative weaknesses in fine motor control, visual learning, and attention in the presence of overall normal intellect, with simple partial seizures associated with more difficulty. Parental concerns for psychosomatic and learning problems were noted. Monitoring select cognitive and behavioral features in BECTS appears appropriate.

The basic helix-loop-helix domain of the aryl hydrocarbon receptor nuclear transporter (ARNT) can oligomerize and bind E-box DNA specifically.

The aryl hydrocarbon receptor nuclear transporter (ARNT) is a basic helix-loop-helix (bHLH) protein that contains a Per-Arnt-Sim (PAS) domain. ARNT heterodimerizes in vivo with other bHLH PAS proteins to regulate a number of cellular activities, but a physiological role for ARNT homodimers has not yet been established. Moreover, no rigorous studies have been done to characterize the biochemical properties of the bHLH domain of ARNT that would address this issue. To begin this characterization, we chemically synthesized a 56-residue peptide encompassing the bHLH domain of ARNT (residues 90-145). In the absence of DNA, the ARNT-bHLH peptide can form homodimers in lower ionic strength, as evidenced by dynamic light scattering analysis, and can bind E-box DNA (CACGTG) with high specificity and affinity, as determined by fluorescence anisotropy. Dimers and tetramers of ARNT-bHLH are observed bound to DNA in equilibrium sedimentation and dynamic light scattering experiments. The homodimeric peptide also undergoes a coil-to-helix transition upon E-box DNA binding. Peptide oligomerization and DNA affinity are strongly influenced by ionic strength. These biochemical and biophysical studies on the ARNT-bHLH reveal its inherent ability to form homodimers at concentrations supporting a physiological function and underscore the significant biochemical differences among the bHLH superfamily.

Autotransplantation as an effective therapy for the loin pain-hematuria syndrome: case reports and a review of the literature.

PURPOSE: The loin pain-hematuria syndrome is a well recognized but poorly understood clinical condition in which patients have progressive loin pain accompanied by hematuria but they maintain stable renal function. We present 2 cases effectively treated with renal autotransplantation, as well as a review of the literature, and a coherent algorithm for the diagnosis and treatment of this condition. MATERIALS AND METHODS: The medical literature concerning the loin pain-hematuria syndrome was reviewed. In 1994 we performed renal autotransplantation on 2 patients with the loin pain-hematuria syndrome at our institution. RESULTS: Extensive urological evaluation revealed no obvious underlying abnormalities in patients with the loin pain-hematuria syndrome. Theories for the pathogenesis of this condition range from thrombotic phenomena to autoimmune processes. Treatment efforts have been directed primarily towards pain management. Narcotic dependence becomes progressive as the pain becomes debilitating. In extreme cases nephrectomy is performed despite normal renal function. Several invasive methods of nerve block and enervation provide only temporary relief. Renal autotransplantation provided lasting cessation of loin pain in both of our patients with followup of 1.5 and 2.5 years, and this intervention has been shown to provide the most durable pain relief in other series. CONCLUSIONS: Renal autotransplantation provides the most durable, nonnarcotic, nephron sparing relief for patients with the loin pain-hematuria syndrome. Further investigation is necessary to elucidate the pathophysiology of this debilitating condition.

Leptomeningeal carcinomatosis: a sequela of cholangiocarcinoma.

Leptomeningeal carcinomatosis is a rare and deceptive presentation of systemic cancer. We report the treatment of a patient with a Klatskin's tumor by surgical resection. The patient presented with symptoms suggestive of liver failure in the early postoperative period. He rapidly developed progressive, multineuroaxis symptoms and died. Routine gastrointestinal evaluation failed to demonstrate any intraabdominal pathologic process that could be responsible for his decline. A MRI of the brain was also unremarkable. Serial lumbar punctures, however, documented leptomeningeal carcinomatosis consistent with a gastrointestinal primary. The clinical presentation of leptomeningeal carcinomatosis is subtle and may masquerade as another disease state. The hallmark of this lethal process is the finding of progressive neurologic deficits at more than one level of the neuroaxis. Serial cerebrospinal fluid examination is often diagnostic. This is the first known report of leptomeningeal carcinomatosis secondary to primary cholangiocarcinoma.

Endoscopic treatment of pediatric urolithiasis.

Children have been slow to benefit from the improvements in stone therapy. Despite the success of less invasive techniques, open surgery for pediatric urolithiasis is still commonly practiced. The authors' goal was to evaluate the indications, efficacy, and complications of endourologic surgery in the treatment of pediatric urolithiasis. They reviewed the treatment of 53 children who had upper tract calculi. Open nephro- and ureterolithotomy were avoided in all cases. The management of 25 children whose stones were not amenable to extracorporeal shock wave lithotriopsy is presented. Seventeen children (19 stones) were treated with miniature ureteroscopes and lasertripsy. Only one (6%) of the patients required ureteral dilation, and only five (29%) needed a postoperative internal stent. Eight children with large renal calculi were treated percutaneously, without transfusion, complication, or evidence of persistent renal damage. All 25 patients were rendered stone-free. The hospital stay was shorter and secondary procedures were less common in comparison to other series of endoscopic lithotripsy. With significant experience in adult endourology and proper instrumentation, one can apply the same techniques to children and achieve equal if not greater benefit. Nephrolithiasis in children is uncommon and should be managed in an institution where endourologists and multiple treatment modalities are available.

Complications of the afferent antireflux valve mechanism in the Kock ileal reservoir.

PURPOSE: Since 1982 the Kock ileal reservoir has been the primary form of urinary diversion in patients requiring lower urinary tract reconstruction at our institution. The intussuscepted afferent nipple valve of the Kock ileal reservoir is designed to prevent reflux and protect the upper urinary tract. Problems associated specifically with the afferent antireflux valve have been few. We defined and characterized all complications associated with the Kock pouch antireflux nipple valve. MATERIALS AND METHODS: From November 1984 through July 1992, 802 patients underwent construction of a continent Kock ileal reservoir. All complications associated with the afferent antireflux valve in this group and their management were identified. RESULTS: Overall, 79 of 802 patients (9.8%) had a total of 84 complications of the afferent antireflux valve (10.4%), including formation of stones on staples securing the afferent nipple valve in 42 cases (5.2%), stenosis of the afferent valve in 35 (4.3%) and prolapse of the valve in 7 (0.9%). A total of 81 patients required surgical intervention to correct the afferent valve complication: 56 (7.0%) were treated endoscopically and 25 (3.1%) required open surgical revision. CONCLUSIONS: We report an overall complication rate of 10.4% associated with the afferent antireflux nipple valve in the Kock ileal reservoir. Most complications can be treated endoscopically without difficulty on an outpatient basis with the use of local sedation. With these results, and only a 3% incidence of open surgical correction of all afferent nipple problems, we encourage the continued use of the intussuscepted afferent nipple valve whenever continent urinary diversion is performed.

Neurofibromatosis and arterial aneurysms.

Neurofibromatosis (NF) is a common autosomal dominant disease characterized by the development of hamartomatous or neoplastic lesions due to the proliferation of neural crest cells. An association of aneurysmal arterial lesions with NF, which may have catastrophic complications, has been rarely reported. Our recent experiences with the diagnosis and management of three male NF patients with aneurysms is described. A 19-year-old-man with refractory hypertension due to unilateral, complex, unreconstructable renal artery aneurysms was successfully treated by nephrectomy. Histopathology demonstrated intramural renal artery Schwann cell proliferation. A 44-year-old patient underwent ligation of a ruptured superior mesenteric artery aneurysm. Finally, a femoral-popliteal artery saphenous vein bypass graft with aneurysm exclusion was performed in a 58-year-old-man with a 3.5 cm symptomatic popliteal artery aneurysm. In NF, the underlying pathology in large arteries is intramuscular Schwann cell proliferation with secondary fibrosis. Mesodermal dysplasia may affect small arteries resulting in stenosis, post-stenotic dilatation, or aneurysmal degeneration. Clinicians should be aware of the unusual association of NF with aneurysms, particularly the occult development of visceral and renal artery aneurysms. These lesions are subject to sudden rupture with potentially devastating consequences, and they mandate a high index of suspicion in NF patients.

Nucleated erythrocytes in maternal blood: quantity and quality of fetal cells in enriched populations.

The discovery of nucleated erythrocytes in maternal circulation provides a potential source for non-invasive prenatal diagnosis. We have evaluated the use of a three-stage procedure to determine the number of cells that are of fetal rather than maternal origin. First, monoclonal antibodies specific for CD45 and CD14 were used in conjunction with a magnetic (MACS) column to deplete unwanted leukocytes from maternal blood. This was followed by a positive MACS enrichment for nucleated erythrocytes, using an anti-CD71 (transferrin receptor) monoclonal antibody. To discriminate between fetal nucleated erythrocytes and those of maternal origin, enriched fractions were simultaneously stained with an anti-fetal haemoglobin (HbF) antibody and hybridized with probes specific for X and Y chromosomes. Samples were then subjected to blind analysis along with negative control samples from non-pregnant volunteers. Using this dual analysis, we were able to determine that less than one nucleated erythrocyte per ml of maternal blood was of fetal origin. Small numbers of these fetal cells were found in 87.5% of pregnancies, ranging from 6 to 35 weeks gestational age. Comparison of HbF and X/Y probe data also suggests that the fetal cells are less suitable for fluorescence in-situ hybridization (FISH) analysis than similar preparations from other sources.

Management and evaluation of localized amyloidosis of the bladder: two case reports.

Localized amyloidosis of the bladder is a rare cause of hematuria, which is often confused with bladder cancer. We present case histories of two patients which illustrate the evaluation and management of this entity. The diagnosis is usually made with biopsy and subsequent pathologic examination. Conservative management is attempted initially but must be individualized according to the clinical course of each patient. Transurethral resection will suffice in most instances but occasionally cystectomy is indicated to control local disease.

Stenosis of the afferent antireflux valve in the Kock pouch continent urinary diversion: diagnosis and management.

Between August 1982 and May 1988, 503 patients underwent construction of a continent ileal reservoir (Kock pouch) for cutaneous urinary diversion at our university. Stenosis of the afferent antireflux valve resulted in upper urinary tract obstruction in 11 patients (2%). In addition, 2 patients underwent Kock pouch diversion elsewhere and upon referral to our institution they had afferent valve stenosis. To date 13 patients have been identified with this problem. Hydronephrosis was present in 100% of the functional kidneys in these patients. Radiographs of the Kock pouch were uniformly normal without evidence of reflux or other pathological condition. The most common presenting symptom was flank pain in 7 patients (54%) and the most common presenting sign was creatinine elevation above baseline in 7 (54%). Infections recurred with or without sepsis in 5 patients (38%). Ureteroileal anastomotic strictures were not present in any patient. The interval from creation of the Kock pouch to the diagnosis of stenosis ranged from 2 to 75 months (mean 39). All patients underwent endoscopic evaluation of the Kock pouch confirming stenosis of the afferent antireflux valve, and subsequent mechanical dilation of the stenotic valve. Dilation procedures were repeated in 6 patients (46%), 4 of whom subsequently required open surgical revision of the afferent valve. Of these patients 3 are clinically stable and 1 died of the primary malignancy. The remaining 2 patients are clinically and radiographically stable after multiple dilations. Of the 7 patients (54%) requiring only a single dilation 6 are clinically stable and 1 died of the primary malignancy. Stenosis of the afferent antireflux valve of the Kock pouch, previously unreported to our knowledge, is a rare late complication leading to flank pain, hydronephrosis, recurrent infection and elevation of serum creatinine levels. Approximately 50% of the patients respond to a single dilation of the nipple valve. However, most patients who require repeat dilation will need open surgical revision.

Technique of mitomycin C instillation in the treatment of upper urinary tract urothelial tumors.

The use of topical agents in the treatment and prophylaxis of transitional cell carcinoma of the bladder is well described. Several physicians have reported the use of these materials in the upper urinary tract for treatment of transitional cell carcinoma. We present our treatment protocol using mitomycin C as topical therapy following endoscopic resection of superficial urothelial tumors of the renal pelvis or ureter. A total of 7 patients was treated during the last 4 years. No systemic side effects due to perfusion with mitomycin C occurred. We believe that our treatment method provides a safe means of delivering topical agents to the upper urinary tract and suggest its use when such treatment is believed to be necessary.

PCR amplification of the 3' external transcribed and intergenic spacers of the ribosomal DNA repeat unit in three species of Saccharomyces.

Two spacer regions outside the ribosomal DNA (rDNA) transcriptional unit in three species of Saccharomyces, S. cerevisiae, S. carlsbergensis and S. pastorianus, were amplified using the polymerase chain reaction. These regions were composed of the 3' external transcribed spacer (ETS) and the intergenic spacer (IGS). Primers were developed from sequence alignments and by taking the reverse complement of a previously described sequence. The region amplified spanned base position 3110 on the 26S rRNA to base position 27 on the 5S rRNA of S. cerevisiae. Nine of the twelve strains used in this study exhibited different restriction profiles, showing that the spacers are highly variable between species. The results suggest that PCR fingerprinting of the non-coding spacer regions can be used to distinguish between closely related Saccharomyces species and may have potential in DNA profiling of other yeasts.

Ureteroscopy: a new asset in the management of postoperative ureterovaginal fistulas.

Iatrogenic ureteral injury, an uncommon entity, is primarily caused by complications of gynecologic surgery. This report describes a case of ureterovaginal fistula discovered 13 days after a vaginal hysterectomy. Ureteroscopy was performed, with passage of an indwelling ureteral stent for 6 weeks. The patient immediately became continent of urine and the fistula healed, thus avoiding the need for further surgery.

Clinical trials of the Northgate SD-3 dual-purpose lithotriptor for renal calculi.

The Northgate SD-3 is a bathless, portable shock wave lithotriptor made in the United States. It uses ultrasound localization and spark-gap, electrode-generated shock waves to fragment calculi in the upper urinary tract. Since October 1987, 312 treatments have been performed on 281 patients (286 kidneys) with stone burdens less than 2 cm. during clinical trials at 6 investigational sites in the United States. A fragmentation rate of 94% was achieved. Of the treatments 78% were judged successful (stone-free or fragments of less than 5 mm. remaining in an asymptomatic patient) and a 3-month stone-free rate of 58% was noted. The retreatment rate was 9% and the ancillary procedure rate was 5%. The complications (hematuria, ecchymosis, pain, obstruction) were mild and not unlike those seen in patients undergoing lithotripsy with other devices.

Endoscopic management of complications of continent urinary diversion.

The Kock pouch continent ileal reservoir has become a therapeutic option for those patients requiring urinary diversion. Complications of this procedure do occur but fortunately many of these may be managed endoscopically without need for open surgical exploration. This report describes experience with 55 patients treated by endoscopic surgery for complications of Kock pouch urinary diversion. This includes 45 patients with stones, 3 with stenotic afferent nipple valves, 3 with suspicion of ureteral or renal pelvic tumor, and 4 with retained upper urinary tract stents. These patients may be treated with intravenous sedation only on an outpatient basis. The procedure was successful in all but 2 patients. One complication occurred when extravasation was noted from the afferent limb. The patient was treated by internal diversion, and follow-up urogram done in forty-eight hours was normal. This experience confirms that endoscopic surgery is an attractive option for treatment of many of the complications resulting from creation of a Kock pouch ileal reservoir.

The effects of extracorporeal shock wave lithotripsy on renal growth, function and arterial blood pressure in an animal model.

The long-term effects of extracorporeal shock wave lithotripsy (ESWL*) on children treated for renal calculi are unclear. To study the long-term bio-effects of this mode of treatment on the immature animal we evaluated 30 New Zealand white rabbits at 7 weeks of age for weight, serum blood urea nitrogen and creatinine, and arterial blood pressure after which they underwent left nephrectomy. Each group of 5 rabbits received ESWL of varying levels (500 to 3,000 shock waves) to the remaining right kidney using the Northgate SD3 lithotriptor (spark gap mediated). One control group received no shock waves. At maturity (16 weeks) the aforementioned parameters were measured again, and the kidneys and any grossly abnormal adjacent organs were examined. We found no significant change in total animal growth, renal growth, renal function or perirenal organs in the post-ESWL groups versus the control group. All post-ESWL groups had an increase in mean arterial blood pressure versus the control group with 3 of 6 groups showing significant increases (p less than 0.05). Histological renal changes, seen at all energy levels of ESWL delivered, included interstitial fibrosis, tubular atrophy, glomeruli destruction, capsular thickening, perivascular fibrosis and mild arteriole wall thickening. Changes were proportional to the number of shocks received. We conclude that ESWL delivered to immature animals does not significantly affect renal growth and function but it can cause significant permanent histological renal changes even at low doses and may result in an increase in adult mean arterial blood pressure.

Urinary tract stones: a complication of the Kock pouch continent urinary diversion.

Urinary tract stone disease has been found to be a later complication associated with the construction of the Kock pouch continent urinary diversion. Of 383 patients who underwent Kock pouch diversion between August 1982 and December 1986 stones developed in the pouch in 64 (16.7%), usually on exposed staples or eroded Marlex used to construct the nipple valves. Stones have recurred in 13 of the 64 patients (22%). Most stones were removed endoscopically with techniques similar to those used for percutaneous stone removal. Risk factors for stone formation include Marlex collar erosion and acute pyelonephritis. Changes in surgical techniques with elimination of the Marlex collar and a reduction in the number of staples have reduced the incidence of this later complication to 10%.

Ureteroscopic retrieval of proximally located ureteral stents.

Indwelling self-retaining ureteral stents are important for the maintenance of urinary drainage in the ureter threatened by obstruction by neoplasm, edema, or calculus. Proximal migration of the stent into the ureter prevents simple cystoscopic retrieval and necessitates removal by other techniques. In this series both rigid and flexible ureteroscopes were used to remove stents from locations ranging from the renal pelvis to the distal ureter in 16 patients. Three-pronged wire graspers was the retrieval instrument most frequently used. Stents were removed in all patients without complication. Ureteroscopy provides the most convenient and least invasive technique for removing stents proximally located in the upper urinary system.