Immunity to jellyfish venoms: suppression of venom-induced immune responses in ultraviolet B-irradiated mice

Lymph node and spleen cells from mice immunized with sea nettle (Chrysaora quinquecirrha) venom exhibited a proliferative response after exposure to the homologous antigen or that of a related jellyfish, Physalia (Portuguese man-o'-war). Native venom was a more effective stimulant than heated, non-lethal venom. Ultraviolet light treatments administered to the skin either before or after venom sensitization suppressed the proliferative response of these internal immune cells.     

Saccharomyces cerevisiae elongation factor 2. Mutagenesis of the histidine precursor of diphthamide yields a functional protein that is resistant to diphtheria toxin

Protein synthesis elongation factor 2 (EF-2) is the target of the ADP-ribosylating activity of diphtheria toxin which is responsible for cell killing. Diphthamide, an unique post-translationally modified histidine residue, is both required for and the site of this ADP-ribosylation. Although present in the EF-2 of all eukaryotes and archaebacteria, the function of diphthamide is unknown. Here we describe the site-specific mutagenesis of the histidine precursor of diphthamide, histidine 699, in yeast EF-2. Plasmid-borne EFT was randomly mutagenized at the histidine 699 codon, and the technique of plasmid shuffling was utilized to select strains that were maintained by the mutant EFT. These mutants were screened for diphtheria toxin resistance. Sequence analysis of the EFT in 49 toxin-resistant isolates showed that histidine 699 had been replaced by 1 of 4 amino acids: asparagine, glutamine, leucine, or methionine. All 11 of the possible codons corresponding to these 4 amino acids were found. The growth rates of cells sustained by the mutant forms of EF-2 were slightly slower than those of isogenic wild-type cells. We conclude that despite its strict conservation and universal post-translational modification, the histidine precursor of diphthamide is not essential to the function of yeast EF-2 in protein synthesis.     

Spinal anaesthesia with 0.5% hyperbaric bupivacaine in elderly patients: effect of site of injection on spread of analgesia

In this randomized, observer-blind study, we have examined, in elderly patients, the effect of site of injection on analgesia levels after spinal injection of 0.5% hyperbaric bupivacaine solution. Thirty male patients, aged 68-87 yr, undergoing minor urological surgery during spinal anaesthesia received 3 ml of a 0.5% hyperbaric bupivacaine solution at either the L3-4 (n = 15) or L4-5 (n = 15) interspace. The solution was injected with the patient in the sitting position. The patient remained sitting for 2 min and was then placed in the supine horizontal position. Analgesia levels were assessed bilaterally using pin-prick. The highest analgesia levels did not differ between groups (medians were approximately T7). There were no significant differences in the time to maximum cephalad spread of analgesia, maximum degree of motor block or haemodynamic changes. We conclude that injection at the L4-5 interspace has no advantage compared with injection at the L3-4 interspace.     

In vitro evaluation of a series of N-dodecanoyl-L-amino acid methyl esters as dermal penetration enhancers

A series of N-dodecanoyl-L-amino acid methyl esters (1-10) and n-pentyl N-acetylprolinate (11) were evaluated for dermal enhancement properties using an in vitro diffusion cell technique. Methods of synthesis of these compounds were described. Enhancers were applied 1 h prior to drug treatment. Hydrocortisone was used as the model drug and was applied to excised hairless mouse skin as a saturated suspension in propylene glycol. Enhancement ratios (ER) were determined for permeability coefficient, 24 h diffusion cell receptor concentration (Q24), and 24 h full-thickness skin steroid content. Controls received no enhancer pretreatment of the skin. N-Dodecanoyl-L-proline (10) showed the highest Q24 value for total steroid (ER 13.7) while N-dodecanoyl-L-phenylalanine (5) showed the highest total steroid skin retention (ER 16.5).     

Microtubule nucleation by gamma-tubulin-containing rings in the centrosome

The microtubule cytoskeleton of animal cells does not assemble spontaneously, but instead requires the centrosome. This organelle consists of a pair of centrioles surrounded by a complex collection of proteins known as the pericentriolar material (PCM). The PCM is required for microtubule nucleation. The minus, or slow-growing, ends of microtubules are embedded in the PCM and the plus, or fast-growing, ends project outwards into the cytoplasm during interphase, or into the spindle apparatus during mitosis. gamma-Tubulin is the only component of the PCM that is so far implicated in microtubule nucleation. Here we use immuno-electron microscopic tomography to show that gamma-tubulin is localized in ring structures in the PCM of purified centrosomes without microtubules. When these centrosomes are used to nucleate microtubule growth, gamma-tubulin is localized at the minus ends of the microtubules. We conclude that microtubule-nucleating sites within the PCM are ring-shaped templates that contain multiple copies of gamma-tubulin.     

Ureteral Stones Clinical Guidelines Panel summary report on the management of ureteral calculi. The American Urological Association

PURPOSE: The American Urological Association convened the Ureteral Stones Clinical Guidelines Panel to analyze the literature regarding available methods for treating ureteral calculi and to make practice policy recommendations based on the treatment outcomes data. MATERIALS AND METHODS: The panel searched the MEDLINE data base for all articles related to ureteral calculi published from 1966 to January 1996. Outcomes data were extracted from articles accepted after panel review. The data were then meta-analyzed to produce outcome estimates for alternative treatments of ureteral calculi. RESULTS: The data indicate that up to 98% of stones less than 0.5 cm. in diameter, especially in the distal ureter, will pass spontaneously. Shock wave lithotripsy is recommended as first line treatment for most patients with stones 1 cm. or less in the proximal ureter. Shock wave lithotripsy and ureteroscopy are acceptable treatment choices for stones 1 cm. or less in the distal ureter. CONCLUSIONS: Most ureteral stones will pass spontaneously. Those that do not can be removed by either shock wave lithotripsy or ureteroscopy. Traditional blind basket extraction, without fluoroscopic control and guide wires, is not recommended. Open surgery is appropriate as a salvage procedure or in certain unusual circumstances.     

Characterization of insulin receptor substrate 4 in human embryonic kidney 293 cells

We recently cloned IRS-4, a new member of the insulin receptor substrate (IRS) family. In this study we have characterized IRS-4 in human embryonic kidney 293 cells, where it was originally discovered. IRS-4 was the predominant insulin-elicited phosphotyrosine protein in these cells. Subcellular fractionation revealed that about 50% of IRS-4 was located in cellular membranes, and immunofluorescence indicated that IRS-4 was concentrated at the plasma membrane. Immunoelectron microscopy conclusively established that a large portion of the IRS-4 was located at the cytoplasmic surface of the plasma membrane in both the unstimulated and insulin-treated states. IRS-4 was found to be associated with two src homology 2 (SH2) domain-containing proteins, phosphatidylinositol 3-kinase and Grb2, the adaptor to the guanine nucleotide exchange factor for Ras. On the other hand, no significant association was detected with two other SH2 domain proteins, the SH2-containing protein tyrosine phosphatase 2 and phospholipase Cgamma. Insulin-like growth factor I acting through its receptor was as effective as insulin in eliciting tyrosine phosphorylation of IRS-4, but interleukin 4 and epidermal growth factor were ineffective.