Bryostatin 1 induces ubiquitin COOH-terminal hydrolase in acute lymphoblastic leukemia cells

It has been previously reported that Bryostatin 1 (Bryo1) induces differentiation of the human acute lymphoblastic leukemia (ALL) cell line, Reh, to a monocytoid B-cell stage. In this study we demonstrate that a novel protein, ubiquitin COOH-terminal hydrolase (UCH-L1), is associated with this differentiation. Reh cells were treated with 200 nmol/l of Bryo1 for 72 h and analyzed for changes in morphology, surface immunophenotype, acid phosphatase and terminal deoxynucleotidyl transferase. Protein patterns of the parent and differentiated cells, by two-dimensional polyacrylamide gel electrophoresis (2D PAGE), were studied. Bryo1-treated cells expressed morphologic, phenotypic and enzymatic features of the monocytoid B-cell stage. The UCH-L1 enzyme (MW-pl 34-5.3) was detected by 2 D PAGE in the differentiated, but not in parent cells. The presence of UCH-L1 in the Bryo1-treated cells was further confirmed by immunoblotting of 2 D PAGE using UCH-L1 polyclonal antibody. Ubiquitin expression was studied in parent and Bryo1-treated cells and was compared with 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated cells. Both agents, TPA and Bryo1, increased the level of ubiquitin expression as detected by flow cytometry. Sodium borohydride, an inhibitor of UCH-L1, inhibited the Bryo1-induced differentiating effect on Reh cells. To date, the mechanism by which Bryo1, exerts its B-cell differentiating effect is not fully understood. This study shows that UCH-L1 expression may play a major role in Bryo1-induced differentiation in pre-B-ALL.     

The contrast enhancement of brain and spinal cord tumors using Gd-DTPA in magnetic resonance tomography with an extra-low magnetic-field intensity

The contrasting agent Gd-DTPA (Magnevist, Schering AG, Germany) was tested when used in magnetic resonance tomography using extra-low (0.04 T) magnetic field intensity in 68 patients with various brain and spine tumors. The agent was injected intravenously in a dose of 0.1 mmol/kg. No complications were found. The tests showed its high efficiency in the diagnosis of brain neoplasms (particularly in malignant intracerebral disorders, meningiomas and neurinomas). Benign astrocytomas induced no noticeable signal intensification on post-contrasting T1-weighed tomograms. In all cases of spinal tumors, the application of Gd-DTPA could specify the extent of tumor invasions, the presence of cysts and identify accessory tumor nodes in one case.     

Recent developments in the synthesis and discovery of oligosaccharides and glycoconjugates for the treatment of disease

The development of the first automated oligosaccharide synthesizer, along with new methods for screening carbohydrate ligand arrays is likely to lead to a rapid acceleration in both our ability to synthesize these molecules, and understand the roles of oligosaccharides and glycoconjugates in biology. Consequently we may uncover new avenues for therapeutic intervention more rapidly. These recent developments are very important since our understanding of the role of glycoconjugates in nature has traditionally fallen far behind that of the other biopolymers such as proteins and nucleic acids as the formation of, for example, glycosylated proteins is not template driven. The chemical synthesis of oligosaccharides and glycoconjugates has provided us with new potential cancer vaccines, antibiotics and new biotechnological tools. Glycobiologists have employed many such tools to uncover new signalling roles for oligosaccharides and glycoconjugates. In this review we aim to highlight some emerging methods for glycoconjugate assembly and screening, and discuss innovative approaches to glycoconjugate based drug design and delivery, all of which are, and will continue to be, fruitful avenues for medicinal chemistry research.     

Poly-(L-lactic) acid membranes in palatal surgery in beagle dogs: clinical and histologic evaluation

This article reports on the histologic findings from a larger study that was designed to investigate whether the attachment of scar tissue to underlying bone, which is normally found after palatal surgery, can be prevented by using biodegradable poly-(L-lactic) acid membranes. Von Langenbeck's procedure was simulated in 12-week-old beagle dogs without clefts. In one group normal wound healing was allowed. In two groups, membranes were inserted immediately after surgery or 3 weeks thereafter. Sham and control groups were also included. Histologic evaluation was carried out at regular intervals. Reports have been published on other aspects, such as clinical wound healing, contraction and maxillary arch development in beagle dogs following this treatment. After direct implantation of membranes, wound healing was retarded. Disintegration of the membranes started soon after implantation and remaining particles were surrounded by a fibroblastic sheath and a fibrous capsule. At sites where membrane particles persisted, attachment of the scar tissue to the underlying bone by Sharpey's fibers was prevented.     

Neurotoxic effects of sodium nitroprusside in rat hippocampal slices

The effect of a permanent transection on myelin gene expression in a regenerating sciatic nerve and in an adult sciatic nerve was compared to establish the degree of axonal control exerted upon Schwann cells in each population. First, the adult sciatic nerve was crushed, and the distal segment allowed to regenerate. At 12 days post-crush, the sciatic nerve was transected distal to the site of crush to disrupt the Schwann cell-axonal contacts that had reformed. Messenger RNA (mRNA) levels coding for five myelin proteins were assayed in the distal segment of the crush-transected nerve after 9 days and were compared to corresponding levels in the distal segments of sciatic nerves at 21 days post-crush and 21 days post-transection using Northern blot and slot-blot analysis. Levels of mRNAs found in the distal segment of the transected and crush-transected nerve suggested that Schwann cells in the regenerating nerve and in the mature adult nerve are equally responsive to axonal influences. The crush-transected model allowed the genes that were studied to be classified according to their response to Schwann cell-axonal contact. The levels of mRNAs were 1) down-regulated to basal levels (P0 and MBP mRNAs), 2) down-regulated to undetectable levels (myelin-associated glycoprotein mRNAs), 3) upregulated (mRNAs encoding 2'3'-cyclic nucleotide phosphodiesterase and beta-actin), or 4) not stringently controlled by the removal of Schwann cell-axonal contact (proteolipid protein mRNAs). This novel experimental model has thus provided evidence that the expression of some of the important myelin genes during peripheral nerve regeneration is dependent on continuous signals from the ingrowing axons.     

Bilateral loss of vestibular function: clinical findings in 53 patients

The clinical presentations and aetiologies of a series of 53 cases of bilateral vestibular failure (BVF) seen by the authors over a decade were evaluated by retrospective review of the medical records. Thirty-nine per cent of patients had associated neurological disease; 13% had a progressive cerebellar syndrome with disabling gait ataxia, abnormal eye movements and cerebellar atrophy on neuro-imaging. BVF was usually unsuspected. Nine per cent had cranial or peripheral neuropathies and in this group there was no abnormality of brain stem/cerebellar oculomotor function, but hearing loss was common. Eleven per cent revealed BVF and hearing loss secondary to meningitis, and 6% had other neurological disorders. Idiopathic BVF was found in 21% of cases, characterised by paroxysmal vertigo and/or oscillopsia, but no abnormal clinical signs. Gentamicin ototoxicity accounted for a further 17%, while autoimmune disease was present in 9% of patients. Otological or neoplastic disease was diagnosed in the remaining 13% of patients. It was concluded that neurological, audiological and ocular motor assessments allow the probable cause of BVF to be defined in approximately 80% of cases. A group of BVF related to autoimmune pathologies is reported for the first time, indicating the need for immunological screening. Idiopathic BVF may present with only minor visual or vestibular symptoms, while in patients with cerebellar degeneration, BVF may be unsuspected and, thus, underdiagnosed.     

Immunolocalization of natriuretic peptide receptor B in the rat kidney

The natriuretic peptide receptor (NPR) family consists of three receptor subtypes: two transmembrane forms that contain a guanylyl cyclase intracellular domain (NPR-A and NPR-B), and one truncated form (NPR-C). Because of the lack of specific agonists and antagonists for each receptor subtype and to the difficulty to detect the presence of small quantities of NPR-B by ligand binding studies, polyclonal antibodies against a peptide whose sequence was chosen from a region of the extracellular domain of rat NPR-B that is not homologous to sequences in NPR-A and NPR-C were developed. Western blotting with affinity-purified anti-NPR-B (413-426)-Tyr revealed a polypeptide of approximately 120 kD on COS-1 cell membranes transfected with rat NPR-B cDNA. The antibody recognized a second polypeptide, approximately 5 to 10 kD smaller, which probably represents the unglycosylated receptor. Anti-NPR-B (413-426)-Tyr did not show crossreactivity to any other NPR. Western blotting analysis with anti-NPR-B (413-426)-Tyr also identified a protein of appropriate size in renal vascular membranes. These results were supported by immunohistochemistry findings that demonstrated staining for NPR-B on papillary and medullary capillaries, glomeruli, and renal arteries. This study concludes that NPR-B is present in the rat kidney, although it was only detected in vascular structures.