Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Paediatric dacryocystorhinostomy

Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease.     

Renal filtration and catabolism of complement protein D

Complement protein D, a serine protease participating in the formation of the C3 convertase of the alternative complement pathway, has the lowest molecular weight (23,750) and serum concentration of all complement proteins. In normal serum, D is the rate-limiting protease of the alternative pathway of complement activation. We report that the serum concentrations of D in 20 patients with chronic renal failure (mean +/- S.D., 0.42 +/- 0.28 mg per deciliter) and in 16 patients on long-term dialysis (1.53 +/- 0.39 mg per deciliter) were significantly higher (P less than 0.001) than in 22 healthy adults (0.18 +/- 0.04 mg per deciliter). In chronic renal failure the serum concentration of D correlated with that of creatinine (r = 0.75, P less than 0.001). The serum concentrations of D found in patients with renal failure reached and in some cases exceeded those at which the protease is no longer rate-limiting. Thus, enhanced activity of the alternative pathway of complement should be expected in patients with advanced renal failure. Urinary D was undetectable (less than 0.2 micrograms per deciliter) in 17 normal adults and either undetectable or below the concentration expected from the degree of proteinuria in 10 patients with nephrotic syndrome. However, in a patient with Fanconi's syndrome the urinary concentration of D (1.3 mg per deciliter) was an order of magnitude higher than the serum concentration, representing 0.5 per cent of the total protein. The urinary D in this patient had normal hemolytic activity, antigenicity, and size. These results indicate that D is filtered through the glomerular membrane and is probably catabolized in the proximal renal tubules.     

Supernumerary marker chromosomes (SMCs) in Turner syndrome are mostly derived from the Y chromosome

DNA and FISH (fluorescence in situ hybridization) analysis were carried out in 12 patients with stigmata of Turner syndrome to determine whether the Supernumerary M arker C hromosome (SMC) found cytogenetically in each of these patients was derived from the Y chromosome. The presence of a Y chromosome in these patients may predispose them to develop gonadoblastoma. PCR-Southern blot analysis, followed by FISH, was used to detect the presence of Y chromosome material. The S ex determining R egion Y (SRY), T estis S pecific P rotein Y -encoded (TSPY) and Y -chromosome R NA R ecognition M otif (YRRM) genes, which map at Yp11.31, Yp11.1–11.2 and Yp11.2/Yq11.21–11.23, respectively, were selected as markers, because they span the whole Y chromosome, and more importantly, they are considered to be involved in the development of gonadoblastoma. It was shown that in 12 patients, all of whom had an SMC, the SMC of 11 was derived from the Y chromosome. Furthermore, the presence of the SRY, TSPY and YRRM gene sequences was determined and FISH analysis confirmed the Y origin of the SMCs. The methodology described in this report is a rapid, reliable and sensitive approach which may be easily applied to determine the Y origin of an SMC carried in Turner syndrome. The identification of an SMC is important for the clinical management and prognostic counseling of these patients with Turner syndrome.