Distribution and self-organization of photosynthetic pigments in micelles: implication for the assembly of light-harvesting complexes and reaction centers in the photosynthetic membrane

The addition of bacteriochlorophylls and bacteriopheophytins to formamide/water, 3:1 (vol/vol), (or water) containing small spherical micelles of Triton X-100 leads to the reorganization of the detergent into micelles that consist of 5000-40,000 amphiphilic molecules. The pigment distribution within the micelles was determined by modified Poisson statistics taking into consideration the various sizes of micelles. Pigment dimerization occurred in micelles with more than a single occupant and was driven by a free-energy change of -4.5 kcal/mol (1 cal = 4.184 J) for bacteriochlorophyll a in formamide/water, -7.6 kcal/mol for bacteriopheophytin a in formamide/water, and -6.6 kcal/mol for bacteriopheophytin a in water. These values correspond to the room temperature equilibrium constants 2.2 x 10(3) M-1, 3.9 x 10(5) M-1, and 7.5 x 10(4) M-1, respectively. The incorporation of bacteriochlorophylls with attached small formamide polymers and the subsequent dimerization of these pigments in the lipid phase provide a model for studying the synergetic organization of polypeptides and bacteriochlorophyll clusters in the photosynthetic membrane.     

Blunt traumatic hematuria in children. Is a simplified algorithm justified?

PURPOSE: We determined whether radiographic evaluation is indicated in all children with traumatic hematuria. MATERIALS AND METHODS: We retrospectively reviewed the records of 110 children from 1992 to 1999 diagnosed with blunt trauma and hematuria. It is routine practice at our emergency department to perform radiographic evaluation in all children with hematuria regardless of the degree. Each chart was evaluated for the mechanism of injury, degree of hematuria, hypotension, imaging studies, renal injury, renal anomalies, associated injuries and outcome. RESULTS: A total of 110 patients 1 to 18 years old (mean age 9) were identified. The most common mechanism of injury was motor vehicle accident in 37 children (34%), followed by a fall in 32 (29%). Grades I to V renal injury was present in 5, 6, 6, 6 and 1 cases, respectively (22%), while 1 (0.9%) involved ureteropelvic junction avulsion. No child had renal pedicle injury. In 9 patients renal anomalies were detected incidentally. Of the 110 patients 101 underwent radiographic evaluation, including computerized tomography in 97 (88%). The 24 patients (22%) with significant renal injury and all with incidentally diagnosed renal anomalies had 50 or greater red blood cells per high power field on urinalysis, while 1 with ureteropelvic junction avulsion presented without hematuria. Hypotension was present in only 3 patients (2.7%), who also had associated injuries, including 2 who presented with renal injury. All 3 with associated injuries. Associated injuries were identified in 11 of 25 patients (44%). The 9 patients (8%) who did not undergo radiographic imaging had negative results on repeat urinalysis with an excellent outcome. CONCLUSIONS: We recommend that radiological evaluation consisting of abdominal and pelvic computerized tomography should be performed only in patients with 50 or greater red blood cells on urinalysis, hypotension at presentation to the emergency room or based on the severity of mechanism of injury, for example high speed motor vehicle accident deceleration injuries. The patient who presented with ureteropelvic junction avulsion without hematuria would have undergone imaging considering the mechanism of injury and number of associated injuries.     

Laser tissue soldering for hypospadias repair: results of a controlled prospective clinical trial

PURPOSE: Laser tissue soldering has been shown to provide safe and effective tissue closure by creating an immediate leak-free anastomosis with minimal scar formation. We compared the results of laser tissue soldering and conventional suturing for hypospadias repair. MATERIALS AND METHODS: A consecutive group of 138 boys 4 months to 8 years old (mean age 15 months) was divided into a standard suturing (84) and a sutureless laser (54) hypospadias repair group. Urethral repair was defined as simple (Thiersch-Duplay or Snodgrass) and complex (onlay island flap or tube) in 101 and 37 cases, respectively. Laser tissue soldering was performed with 50% human albumin solder doped with 2.5 mg./ml. indocyanine green dye using an 808 nm. diode laser at 0.5 W. In the laser group sutures were used for tissue alignment only. At surgery neourethral and penile length, operative time for neourethral construction and the number of sutures or throws were measured. Postoperatively patients were examined for complications of wound healing, stricture or fistula. RESULTS: Mean patient age, urethral defect severity, type of repair, neourethral length and stenting time plus or minus standard error of mean were not significantly different in the 2 groups. Mean operative time was a fifth as long for laser tissue soldering in simple and complex hypospadias repair compared to controls (1.5 +/- 0.1 and 5.1 +/- 0.3 versus 8.5 +/- 0.8 and 26.7 +/- 1.7 minutes, respectively, p <0.001). The mean number of sutures used for tissue alignment in the laser group for simple and complex repair was significantly less than in controls (3.0 +/- 0.2 and 8.2 +/- 0.6 versus 8.5 +/- 0.8 and 23.2 +/- 1.5, respectively, p <0.001). All patients were followed a mean of 12 months (minimum 6, maximum 22). The complication rate was 4.7% in the laser group and 10.7% in controls with fistula in 2 of 54 cases, and fistula and meatal stenosis in 7 and 2 of 84, respectively. CONCLUSIONS: These preliminary results indicate that laser tissue soldering for hypospadias repair may be performed in almost sutureless fashion and more rapidly than conventional suturing. The ease of the laser technique and the lower complication rate in the laser group indicate that laser tissue soldering is an acceptable means of tissue closure in hypospadias repair.     

A simple cuvette for densitometric scanning of polyacrylamide gel electrophoresis cylinders. Quantitation of aggregates in preparations of human serum albumin

A simple and inexpensive cuvette for the densitometric evaluation of polyacrylamide gel electrophoresis is described. The method has been tested using preparations of human serum albumin and its aggregates as a model. The principle of the technique is not restricted to one particular densitometer.     

Urological manifestations of Down syndrome

PURPOSE: We identified the urological anomalies seen in patients with Down syndrome. MATERIALS AND METHODS: We reviewed the literature on Down syndrome and its associated genitourinary pathology. RESULTS: Associated defects have been reported throughout the genitourinary tract. The most common renal anomalies seen are renal hypoplasia, obstructive uropathy and glomerular microcysts. Decreased creatinine clearance has also been noted. Developmental anomalies, such as megaureter and vesicoureteral reflux, have been reported. Dysfunctional voiding and urinary retention have been found in these patients. Posterior urethral valves and hypospadias have also been seen. The testicular abnormalities most frequently reported are cryptorchidism, testicular cancer and infertility. CONCLUSIONS: Improved understanding and identification of the various urological anomalies associated with Down syndrome will aid in the care of these patients. In addition, an awareness of perioperative issues will further facilitate a smooth clinical course.     

Pharmacology of the urotensin-II receptor antagonist palosuran (ACT-058362; 1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt): first demonstration of a pathophysiological role of the urotensin System

Urotensin-II (U-II) is a cyclic peptide now described as the most potent vasoconstrictor known. U-II binds to a specific G protein-coupled receptor, formerly the orphan receptor GPR14, now renamed urotensin receptor (UT receptor), and present in mammalian species. Palosuran (ACT-058362; 1-[2-(4-benzyl-4-hydroxy-piperidin-1-yl)-ethyl]-3-(2-methyl-quinolin-4-yl)-urea sulfate salt) is a new potent and specific antagonist of the human UT receptor. ACT-058362 antagonizes the specific binding of (125)I-labeled U-II on natural and recombinant cells carrying the human UT receptor with a high affinity in the low nanomolar range and a competitive mode of antagonism, revealed only with prolonged incubation times. ACT-058362 also inhibits U-II-induced calcium mobilization and mitogen-activated protein kinase phosphorylation. The binding inhibitory potency of ACT-058362 is more than 100-fold less on the rat than on the human UT receptor, which is reflected in a pD'(2) value of 5.2 for inhibiting contraction of isolated rat aortic rings induced by U-II. In functional assays of short incubation times, ACT-058362 behaves as an apparent noncompetitive inhibitor. In vivo, intravenous ACT-058362 prevents the no-reflow phenomenon, which follows renal artery clamping in rats, without decreasing blood pressure and prevents the subsequent development of acute renal failure and the histological consequences of ischemia. In conclusion, the in vivo efficacy of the specific UT receptor antagonist ACT-058362 reveals a role of endogenous U-II in renal ischemia. As a selective renal vasodilator, ACT-058362 may be effective in other renal diseases.