Perforation of terminal ileum diverticulitis: a case report and literature review.

Terminal ileum diverticulosis is a rare entity, but it can be complicated by diverticulitis and perforation, which clinically can be indistinguishable from acute appendicitis. A case report and review of the literature is presented.

The effect of helmets on the incidence and severity of head and cervical spine injuries in motorcycle and moped accident victims: a prospective analysis based on emergency department and trauma centre data.

The aim of this prospective study was to quantify the anatomic severity of head and cervical spine injuries in hospital admitted victims of motorcycle and moped accidents in relation to helmet use and controlled for non-head injuries (i.e. kinetic impact). Two hundred and twenty-three patients entered the study group, of which 152 were motorcyclists and 71 were moped riders. Our results reveal that helmets do prevent head injury in motorcycle and moped accidents, especially in those crashes involving relatively low kinetic energy transfers. Helmet use does not lead to an increase of the incidence or severity of cervical spine injury. As a result compulsory helmet laws should not be limited to motorcyclists but also focus on all moped riders and probably also bicyclists. This study illustrates that emergency departments can provide important epidemiological information for injury control purposes. However, the epidemiological use of emergency department data and hospital data in general requires cautiousness. Confounding is a common problem which should be dealt with during analysis.

Use of cyanoacrylate (super glue) for the fixation and prefabrication of nasal cartilage grafts.

BACKGROUND: Cartilage grafts are frequently too small to serve as dorsal grafts so that several segments must be secured together to achieve adequate dimensions. The suturing of graft segments is time-consuming and difficult. OBJECTIVE: This study examines the use of 2-octyl cyanoacrylate for the prefabrication and fixation of nasal cartilage grafts. METHODS: 2-octyl cyanoacrylate was used to prefabricate cartilage grafts and secure nasal tip grafts in 9 patients who underwent open rhinoplasty. RESULTS: Cartilage grafts appeared to maintain their volume and position. There was no evidence that 2-octyl cyanoacrylate led to inflammation, erythema, or fibrosis. CONCLUSIONS: 2-octyl cyanoacrylate is an effective method for prefabricating and securing nasal cartilage grafts. There were no negative sequelae associated with its use in this series of patients. (Aesthetic Surg J 2001;21:328-333.).

Purification and properties of a palmitoyl-protein thioesterase that cleaves palmitate from H-Ras.

H-Ras, the protein product of the cellular homologue of the Harvey ras oncogene, undergoes a complex series of post-translational modifications that include C-terminal isoprenylation, proteolysis, methylation, and palmitoylation. Palmitoylation has been shown to enhance the transformation efficiency of H-Ras about 10-fold in vivo. A recent study (Magee, A. I., Gutierrez, L., McKay, I. A., Marshall, C. J., and Hall, A. (1987) EMBO J. 6, 3353-3357) has provided strong evidence that the palmitate undergoes a dynamic acylation-deacylation cycle, but details concerning the enzymology of this process and its regulation are lacking. To begin to dissect this event, we have developed an assay for the enzymatic removal of palmitate from [3H]palmitate-labeled H-Ras. This substrate was produced in a baculovirus expression system and was used to purify to homogeneity a novel 37-kDa enzyme from bovine brain cytosol that removes the radiolabeled palmitate. The purified enzyme is sensitive to diethyl pyrocarbonate and insensitive to phenylmethylsulfonyl fluoride and N-ethylmaleimide. Interestingly, the thioesterase recognizes H-Ras as a substrate only when H-Ras is in its native conformation (bound to Mg2+ and guanine nucleotide). The palmitoylated alpha subunits of the heterotrimeric G proteins are also substrates for the enzyme.

Treatment philosophy and retreatment rates following piezoelectric lithotripsy.

Second generation lithotriptors offer the advantage of anesthesia-free fragmentation of renal and ureteral calculi but they frequently require multiple treatments to attain a stone-free status. However, excessive single lithotripsy sessions or multiple treatments may be associated with significant damage to the kidney. For some clinicians a common treatment philosophy involves evaluation of serial plain abdominal films every 24 hours after lithotripsy and immediate retreatment of all patients with incomplete fragmentation. To avoid unnecessary retreatments and, thus, minimize potential renal damage, we prospectively evaluated 100 patients undergoing lithotripsy on a Wolf Piezolith 2300 device. Patients were routinely treated with 4,000 shocks at 1,100 bar. Serial plain abdominal films were obtained at 1 day and 2 weeks after lithotripsy. The need for retreatment was determined by the plain abdominal film results. Additional therapy was considered necessary if there was no stone fragmentation or if residual fragments measured greater than 4 mm. Of the patients whose plain abdominal film at 24 hours indicated the need for a repeat treatment 43% were stone-free on the 2-week film. Thus, these patients were spared an unnecessary treatment by allowing adequate time for the stone fragments to pass spontaneously. Our data suggest that repeat treatments on second generation lithotriptors should not be performed within 24 hours. Rather, the patient should be reevaluated at least 1 to 2 weeks later to avoid unnecessary retreatment with the attendant potential for renal injury. In addition, when comparing the retreatment rates of various lithotriptors, one should also consider the treatment philosophy used at the particular institution and the timing of the radiographic studies used to determine the stone-free status.

Defective mannosylation of glycosylphosphatidylinositol in Lec35 Chinese hamster ovary cells.

The Lec35 mutation (previously designated PIR) of Chinese hamster ovary cells is a recessive mutation that affects the participation of mannose-P-dolichol (MPD) in dolichol-P-P-oligosaccharide biosynthesis in vivo, even though MPD and the respective MPD-dependent mannosyltransferases are present. The Lec35 phenotype can be partially corrected by disrupting Lec35 cells and performing the transferase reactions in vitro, suggesting that the defect may be related to mislocalization of MPD. In this study, we examined the effect of the Lec35 mutation on glycosylphosphatidylinositol (GPI) lipid biosynthesis, another pathway that requires MPD. Our data indicate that the first mannosylation reaction of GPI lipid biosynthesis is defective in Lec35 cells, with the accumulation of glucosaminylphosphatidylinositol having a fatty acyl group on inositol and a base-resistant alkyl group attached to glycerol. The same intermediate accumulates in Lec15 (MPD synthase-defective) cells. The defective mannosylation reaction of Lec35 cells was corrected in vitro and shown to require MPD. These results demonstrate that the Lec35 gene governs a general aspect of MPD metabolism affecting both GPI lipid and dolichol-P-P-oligosaccharide biosynthesis. To provide additional insight into the role of the Lec35 gene, we give evidence for an inefficient pool of MPD in Lec35 membranes.

Molecular cloning and expression of palmitoyl-protein thioesterase.

We have previously reported the purification of a palmitoyl-protein thioesterase (PPT) from bovine brain that removes palmitate from Ha-Ras (Camp, L. A., and Hofmann, S. L. (1993) J. Biol. Chem. 268, 22566-22574). In the current paper, we have isolated bovine and rat cDNA clones encoding PPT. The deduced amino acid sequence of PPT predicts a protein of 306 amino acids that contains amino acid motifs characteristic of thioesterases: "Gly-X-Ser-X-Gly" positioned near the NH2 terminus and "Gly-Asp-His" positioned near the COOH terminus of the protein. The identity of the PPT cDNA was further confirmed by expression in simian COS cells and insect Sf9 cells. Comparison of the DNA and protein sequence data suggests that a hydrophobic NH2-terminal sequence of 27 amino acid residues is removed from the primary translation product. Furthermore, the recombinant protein and the native protein purified from bovine brain contain complex asparagine-linked oligosaccharides and a large proportion of the expressed PPT is secreted from COS and Sf9 cells. Thus, while the palmitoyl-protein thioesterase will deacylate intracellular palmitoylated proteins such as Ha-Ras and the alpha subunits of heterotrimeric G proteins, the physiologic substrates are likely to be externally oriented or secreted proteins.

A second maternally expressed Drosophila gene encodes a putative RNA helicase of the "DEAD box" family.

Recently, a family of proteins containing the conserved motif Asp-Glu-Ala-Asp, the "DEAD box" proteins, has been identified. This family is typified by the eukaryotic translation initiation factor eIF4A, and its members are believed to share the functional property of ATP-dependent RNA unwinding. One of the previously identified members of this family (vasa) is the product of a maternally expressed gene from Drosophila melanogaster that is known to play a role in the formation of the embryonic body plan. We report here the isolation of a Drosophila gene that has an mRNA expression pattern somewhat similar to that of vasa and also encodes a DEAD box protein. We have termed this gene ME31B to reflect its maternal (ovarian germ-line) expression and its location within the 31B chromosome region. Comparisons with the other members of this family reveal that although ME31B is most like the protein Tif1/Tif2, which probably represents the Saccharomyces cerevisiae version of eIF4A, it is unlikely that ME31B represents the Drosophila eIF4A protein per se. A search for mutations in the ME31B gene has established that the P element which causes the female-sterile mutation flipper lies in the 3' flank of the ME31B gene.

Mutations in the palmitoyl protein thioesterase gene causing infantile neuronal ceroid lipofuscinosis.

Neuronal ceroid lipofuscinoses (NCL) represent a group of common progressive encephalopathies of children which have a global incidence of 1 in 12,500. These severe brain diseases are divided into three autosomal recessive subtypes, assigned to different chromosomal loci. The infantile subtype of NCL (INCL), linked to chromosome 1p32, is characterized by early visual loss and rapidly progressing mental deterioration, resulting in a flat electroencephalogram by 3 years of age; death occurs at 8 to 11 years, and characteristic storage bodies are found in brain and other tissues at autopsy. The molecular pathogenesis underlying the selective loss of neurons of neocortical origin has remained unknown. Here we report the identification, by positional candidate methods, of defects in the palmitoyl-protein thioesterase gene in all 42 Finnish INCL patients and several non-Finnish patients. The most common mutation results in intracellular accumulation of the polypeptide and undetectable enzyme activity in the brain of patients.

Functional importance of the amino terminus of Gq alpha.

Gq alpha is palmitoylated at residues Cys9 and Cys10. Removal of palmitate from purified Gq alpha with palmitoylthioesterase in vitro failed to alter interactions of Gq alpha with phospholipase C-beta 1, the G protein beta gamma subunit complex, or m1 muscarinic cholinergic receptors. Mutants C9A, C10A, C9A/C10A, C9S/C10S, and truncated Gq alpha (removal of residues 1-6) were synthesized in Sf9 cells and purified. Loss of both Cys residues or truncation prevented palmitoylation of Gq alpha. However, truncated Gq alpha and the single Cys mutants activated phospholipase C-beta 1 normally, while the double Cys mutants were poor activators. Loss of both Cys residues impaired but did not abolish interaction of Gq alpha with m1 receptors. These Cys residues are thus important regardless of their state of palmitoylation. When expressed in HEK-293 or Sf9 cells, all of the proteins studied associated entirely or predominantly with membranes, although a minor fraction of nonpalmitoylated Gq alpha proteins accumulated in the cytosol of HEK-293 cells. When subjected to TX-114 phase partitioning, a significant fraction of all of the proteins, including those with no palmitate, was found in the detergent-rich phase. Removal of residues 1-34 of Gq alpha caused a loss of surface hydrophobicity as evidenced by complete partitioning into the aqueous phase. The Cys residues at the amino terminus of Gq alpha are thus important for its interactions with effector and receptor, and the amino terminus conveys a hydrophobic character to the protein distinct from that contributed by palmitate.