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.     

A 22-nucleotide spliced leader sequence in the human parasitic nematode Brugia malayi is identical to the trans-spliced leader exon in Caenorhabditis elegans.

The mRNAs encoding a 63-kDa antigen in the human parasitic nematode Brugia Malayi contain a spliced leader sequence of 22 nucleotides (nt) that is identical to the trans-spliced leader found on certain actin mRNAs in the distantly related nematode Caenorhabditis elegans. The 22-nt sequence does not appear to be encoded near the 63-kDa genes but is present in multiple copies in several locations within the parasite genome, including the 5S rRNA gene repeat. The 5S-linked copies of the 22-nt sequence are transcribed to yield a 109-nt nonpolyadenylated RNA with the 22-nt leader sequence at its 5' end. We suggest that the 22-nt leader is acquired by 63-kDa antigen mRNAs through trans-splicing. These results indicate that trans-splicing is widespread in nematodes and argue for the functional significance of the 22-nt spliced leader exon in nematode mRNA metabolism.     

HLA-DR and H-2E transgenes differentially mediate TCR-specific positive selection

The use of HLA transgenic mice in models of immunity and diseaseassumes that human MHC molecules are able to contribute towardthe positive selection of the mouse TCR repertoire. As an initialstep towards analysis of this we have compared the relativeability of DR/Eß or E/Eß complexes to induceT cell receptor (TCR) positive selection in H-2Ea and HLA-DRAtransgenic mice lacking endogenous E. The results show that,like E/Eß, the hybrid DR/ß complexes arecapable of mediating positive selection of V_ß2⁺;,V_ß6⁺, and V_ß10⁺ cells. However, differenceswere found between the effects of the two transgenes. Thus,while V_ß6⁺ cells were efficiently selected in bothH-2Ea and DRA transgenic mice, positive selection of V_ß10⁺cells was less apparent in the DRA transgenic mice. Variationbetween Ea and DRA transgenic mice is consistent with the notionthat this process is dependent on differential binding of endogenouspeptides to the E/Eß and DR/Eß complexes.Furthermore, contrary to expectations, in neither set of micewas positive selection limited solely to the CD4⁺ subset. Thus,examples were found in which V_ß-specific positiveselection was confined to either the CD4⁺ or CD8⁺ subsets, andothers in which both subpopulations were concomltantly increased.In the case of V_ß2 positive selection, H-2Ea transgenicmice showed expansion of these cells in both the CD4⁺ and CD8⁺subpopulations whlle in DRA transgenic mice this occurred predominantlyin the CD8⁺ subpopulatlon.     

Immunohistochemical characterization of an anti-epithelial monoclonal antibody (mAB lu-5)

Summary A mouse monoclonal antibody (mAB lu-5) was prepared using a lung cancer cell line as an antigen. The selected clone produces an IgG with a gamma-1 heavy chain and a kappa-light-chain. Immunohistochemical testing of mAB lu-5 on 117 normal tissue biopsies and 474 tumours revealed reactivity with an intracytoplasmic, formaldehyderesistant antigen present in most epithelial and mesothelial cells, but absent in mesenchymal cells. The antibody can therefore be used as a first order, pan-epithelial marker. It proved also useful for fast tumour diagnosis on frozen sections.     

The p150,95 molecule is a marker of human mononuclear phagocytes: comparison with expression of class II molecules

A new monoclonal antibody (mAb), named 3.9, is described that is specific for the p150,95 molecule, a member of the LFA-1, CR3, p150,95 family of human leukocyte differentiation antigens. The LFA-1 molecule participates in a variety of T cell interactions and the CR3 molecule is the receptor for the complement component iC3b, but little is known about the p150,95 molecule. Here we show that the expression of p150,95 is confined to myeloid cells. mAb 3.9 reacts variably with neutrophils, more strongly with monocytes and is most strongly expressed on tissue macrophages. Using this mAb and others, we have examined the heterogeneity of tissue macrophages. Cells such as Langerhans' cells, dendritic reticulum cells and osteoclasts failed to react with these mAb and thus, probably do not belong to the mononuclear phagocyte lineage. Using a new double-labeling technique, we investigated lymphoid tissue for dendritic cells bearing class II molecules which might function in interactions with T cells. In T cell areas macrophages expressing class II markers were seen but there was no evidence for other types of dendritic or interdigitating cells which expressed class II molecules but not macrophage epitopes. The conclusion from this survey was that the most prominent cell with dendritic morphology found in the T cell areas of lymphoid tissue was a macrophage.     

Binding of 3H-estradiol-17 beta-(beta-D-glucuronide), a cholestatic organic anion, to rat liver plasma membranes. Evidence consonant with identification of organic anion carriers

The binding of 3H-estradiol-17 beta(beta-D-glucuronide) (3H-E2 17G), a cholestatic organic anion, was examined in rat liver plasma membranes, and two saturable, specific binding sites were identified. The binding parameters are Kd1 = 3.9 X 10(-7) M, Bmax1 = 69 pmol/mg of protein; Kd2 = 4.90 X 10(-6) M, Bmax2 = 495 pmol/mg of protein according to Scatchard analysis of equilibrium experiments. Kinetic dissociation experiments showed that 3H-E2 17G binding was reversible and revealed two components. The dissociation rate constants did not vary with the method of dilution of radioligand, i.e., by "infinite" volume, or excess unlabeled ligand, ruling out the possibility of cooperativity. The rate of association of 3H-E2 17G binding was very rapid, so that maximal binding was reached within 15 sec at 4 degrees. Na+ was not required for binding and binding was not decreased in the presence of high osmolarity buffer (125 mM sucrose), indicating that transport into vesicles was not involved. The ability of a series of compounds to inhibit the binding of 3H-E2 17G was also examined. Taurocholate, cholate, taurodehydrocholate, and testosterone glucuronide were identified as ligands selective for the high affinity site (site 1). The A- and D-ring glucuronide conjugates of estradiol and estriol, bromosulfophthalein, dibromosulfophthalein, and the glucuronide conjugates of phenolphthalein, 4-methylumbelliferone, and menthol inhibited binding of 3H-E2 17G to both sites. Morphine glucuronide, estradiol, and glucuronic acid did not inhibit binding to either site. The substrate specificities of binding to the low affinity site (site 2) are consistent with data characterizing the transport of these substrates in hepatocytes and supports the postulate that site 2 represents a non-bile acid organic anion carrier. Site 1 is postulated to represent a carrier shared by the bile acids and non-bile acid organic anions.