An approach for fluorometric determination of glycosyltransferase activities.

A new strategy for the fluorometric determination of glycosyltransferase activities is reported. The method involves dansyl chloride derivatization of the reduced form (pNH2phenyl) of a hydrophobic, aglycon moiety covalently linked to a number of acceptor substrates (pNO2phenyl). Focusing on the Golgi enzyme core 2 N-acetyl-glucosaminyltransferase, we found that synthesis and fractionation of the dansylated substrate derivative were rapid, easy and inexpensive.

Pattern of anesthetic diffusion during peribulbar infiltration: a CT evaluation.

Purpose: The aim of this study was to evaluate the changes undergone by orbital structures during peribulbar anesthesia.

Methods: CT-thin slices were acquired and 8-9 ml of anesthetic, with a small part of low-density non-ionic water-soluble contrast medium were injected under CT guide once to follow extraconal spreading and diffusion to intraconal structures and above all, the surgically important structures such as recti muscles, orbicular and optic nerve sheath. Conjunctival sack involvement was assessed and conjunctival chemosis was rated.

[Iron accumulation in the liver of patients with thalassemia major assessed with low field strength magnetic resonance: correlation with clinico-instrumental parameters].

Eight transfusion dependent patients (3 women and 5 men) with thalassemia major undergoing long-term treatment with Desferoxamine were submitted to MRI, with T2* GE sequences and low field strength. The ratio between liver mean signal intensity and skeletal muscle (L/M) and the ratio between the former and subcutaneous fat (L/F) were calculated in all patients. The results were compared with those of a control group of 7 healthy volunteers (7 men).

[Biomechanical changes in and lesions of the lumbosacral spine in horse riding. Magnetic resonance assessment].

Spinal injuries account for 5-15% of sport-related traumas. Equestrian sports are considered, together with rugby, motor sport and diving, the riskiest sport for severe spinal injuries. We investigated the biomechanical changes and repeated microtraumas in equitation.

Purification and properties of human urinary beta-D-mannosidase.

Two forms of the lysosomal enzyme beta-mannosidase were identified and purified from human urine. The purification strategy employed allowed sufficient quantities of both forms to be obtained for subunit analysis and for further characterizations. The two beta-mannosidases were identified as beta-mannosidase B and A, in order of their elution from an ion-exchange column.

No evidence of the hook effect in peritoneal fluid CA 125 measurement using immunoenzymatic second generation assays: comparison with immunoradiometric assays.

Objective: To monitor the occurrence of the hook effect in measurements of peritoneal fluid CA 125 levels using two different immunoenzymatic second generation assays (ETI-II and EIA-II), and to compare these results with those obtained using the respective immunoradiometric versions of the assays (IRMA-II and ELSA-II).

Study Design: CA 125 levels were determined in peritoneal fluid and serum samples obtained from 45 women with gynecological diseases. The assays were carried out using IRMA-II and ETI-II (Sorin Biomedica) and ELSA-II and EIA-II (CIS Bio International) assays.

Neuromagnetic fields of the brain evoked by voluntary movement and electrical stimulation of the index finger.

Neuromagnetic fields from the left cerebral hemisphere of five healthy, right-handed subjects were investigated under two different experimental conditions: (1) electrical stimulation of the right index finger (task somatosensory evoked fields, task SEF's), and (2) voluntary movement of the same finger referred to as movement-related fields, (MRFs). The two conditions were, performed in random order every 5-8 s. In addition, the task SEF's were compared to control SEF's recorded at the beginning of the experiment in order to find the optimal dewar position for localizing the central sulcus.

[Computerized tomography assessment of bone damage following injury of the anterior cruciate ligament].

An ACL tear causes an anterior subluxation of the tibial bone which rotates with its fulcrum on the medial collateral ligament; consequently, the lateral femoral condyle impacts on the external tibial plateau. The presence of a subcortical lesion of the spongiform bone in the posterior external tibial plateau is an indirect sign of an ACL tear. On MR images, traumatic changes are depicted as changes in bone marrow signals.

Beta-N-acetylhexosaminidases A and S have similar sub-cellular distributions in HL-60 cells.

In HL-60 cells the most abundant isoenzymes of beta-N-acetyl-hexosaminidase are A (alpha beta) and S (alpha alpha). Sub-cellular fractionation of HL-60 cells by differential centrifugation showed that both A and S forms were present in the lysosomal and post-lysosomal (soluble) fractions in approximately equal abundance. Ion-exchange chromatography showed that a fraction enriched with plasma membranes had the A form, and a form of beta-N-acetylhexosaminidase less acidic than A, but there was no S.

A fluorescent assay for the determination of UDP-GlcNAc: Gal beta 1,3GalNAc-R (GlcNAc to GalNAc) beta 1,6-N-acetylglucosaminyltransferase activity.

A fluorescent assay for UDP-GlcNAc: Gal beta 1,3Gal-NAc-R beta 1,6-N-acetylglucosaminyltransferase (core 2 GlcNAc-T) activity has been developed involving dansylation of the enzyme reaction product. Core 2 GlcNAc-T detection was performed using unlabeled UDP-GlcNAc as the donor and Gal beta 1,3GalNAc alpha-pAp as the acceptor. The product, Gal beta 1,3(GlcNAc beta 1,6)-GalNAc alpha-pAp, was quantitatively derivatized with dansyl chloride at the NH2 moiety of the pAp group and the resultant fluorescent trisaccharide was separated on a Spherisorb ODS2 HPLC column.

Platelet glycohydrolase activities: characterization and release.

Granules containing acid hydrolases have been detected in human platelets but have not been thoroughly characterized. We have studied the activity and characteristics of glycohydrolases present in normal human platelets, evaluated their release upon stimulation with thrombin, and assessed the contribution of platelet - released lysosomal contents to the glycohydrolase activity present in normal serum. Platelets contained a remarkable glycohydrolase activity with a prevalence of beta - N-acetylhexosaminidase.

Partial sequence of the purified protein confirms the identity of cDNA coding for human lysosomal alpha-mannosidase B.

Human lysosomal alpha-mannosidase has been purified by a simple and rapid method in sufficient quantities for the analysis of its subunit composition and partial protein sequencing. Analysis of the N-terminal residues of the 30 kDa polypeptide has enabled us to confirm the identity of the recently cloned cDNA that was tentatively identified as that of lysosomal alpha-mannosidase [Nebes and Schmidt (1994) Biochem. Biophys.

Influence of cell differentiation and protein kinase C activation on sub-cellular distribution of beta-N-acetylhexosaminidases of HL 60 cells.

There have been several accounts regarding the alterations of the lysosomal enzyme beta-N-acetylhexosaminidase in human leukaemic cells. In addition to Hex A (alpha beta) and Hex B (beta beta) forms, leukaemic cells contain a third isoenzyme displaying many characteristics in common with Hex S, the alpha alpha dimer representing the residual activity in patients with Sandhoff's disease. In the human leukaemic cell line HL 60, A (alpha beta) and S (alpha alpha) are the most abundant forms.

GM2 activator protein expression in mouse tissues.

The GM2 activator protein is an essential cofactor of hexosaminidase A in the degradation of GM2 ganglioside and it is responsible for the variant AB of GM2 gangliosidosis in man. In this study GM2 activator protein and its mRNA were determined in different mouse tissues. It was found that this protein is expressed mostly in the spleen and testis followed by brain and kidney which represent the main source in man.

Organization of the gene for the alpha-subunit of mouse beta-N-acetylhexosaminidase (HEXa).

Genomic clones spanning the mouse HEXa gene were isolated and the exon-intron organization determined. The locations of all exon-intron junctions were identical to those of the human HEXa gene but the large intron 1 was shorter in the mouse (14Kb) than in the human gene (18Kb).

[Magnetic resonance imaging in denervated muscle. A preliminary study].

Ten patients with various forms of peripheral neuropathy and spinal radiculopathy were examined with MRI using a low-field permanent magnet (0.2 T) and spin echo (SE)/inversion recovery (IR) sequences, with an adequate inversion time to suppress healthy muscle signal. In acute denervation MR sensitivity was low on both sequences; in subacute denervation the damaged muscle was more intense than the healthy muscle only on IR sequences.

Advances in interventional radiology in oncology.

Interventional radiology (IR) includes all procedures performed percutaneously under US, fluoroscopy, CT or DSA guidance by a radiologist to obtain diagnostic and therapeutic achievements. According to the pathology under examination, these procedures may be applied alone, as a definite therapeutic tool, or together with other traditional techniques permitting an easier and more successful application. In this report the authors discuss briefly the IR possibilities in many oncological branches.

Different expression of beta-N-acetylhexosaminidase in mouse tissues.

The expression of genes encoding for the alpha and beta-subunits of the lysosomal enzyme beta-N-acetylhexosaminidase was investigated in different mouse tissues. It was found, using fluorogenic substrates, that the amounts of alpha and beta subunits were not the same in different tissues: alpha-subunit was more abundant in the brain, beta-subunit in epididymis and brain. The different isoenzyme patterns and specific activities in mouse tissues are due to the differences in the amount of hexosaminidase subunits.

Cloning and sequence analysis of a cDNA clone coding for the mouse GM2 activator protein.

A cDNA (1.1 kb) containing the complete coding sequence for the mouse GM2 activator protein was isolated from a mouse macrophage library using a cDNA for the human protein as a probe. There was a single ATG located 12 bp from the 5' end of the cDNA clone followed by an open reading frame of 579 bp.

Blood testosterone levels are correlated with beta-N-acetylhexosaminidase activity in human caput epididymis.

beta-N-acetylhexosaminidase exhibits a relatively high activity in human epididymis. Its isoenzymatic profile and immunological properties led us to conclude that the increased activity was not due to the expression of an isoform unrelated to the HEX A and B present in other human tissues. Measurement of enzyme levels in the three distinct epididymal regions revealed that in any given sample, activity was higher in the caput than in the corpus or cauda.

[MR staging in renal neoplasms. Comparison with surgical data].

Forty-six patients bearing renal lesions were studied with magnetic resonance (MR) imaging. A superconductive magnet (1.5 T) was used to stage the lesions according to Robson's criteria.

Percutaneous treatment of hepatic cysts by aspiration and sclerotherapy.

We treated 35 patients who had hepatic cysts (30 congenital cysts, 5 hydatid cysts) with percutaneous puncture and sclerotherapy. After puncture and drainage of the cyst, a 95% alcohol solution was instilled as sclerosing agent into the cystic cavity. In all the patients, cyst puncture and drainage was successful.