Clotting Problems with the Teflon-Silastic Arteriovenous Shunt in Patients on Regular Haemodialysis

Episodes of clotting that occurred in 22 patients on regular haemodialysis were studied over a six-month period. The venous pressure during dialysis and the radiology of the Teflon-Silastic arteriovenous shunt were found to be satisfactory guides for the management of the shunt. The failure of the shunt during the early stage was mainly due to technical reasons. Histological study of the excised vessels in removed long-term shunts showed that these had failed because of rigidity and thickening of the vessel wall due to calcium and iron deposits or chronic inflammation, or both.     

Deoxyribonucleic Acid Base Compositions of Selected Mycoplasmas and L-Phase Variants

Deoxyribonucleic acid base compositions were determined for 25 Mycoplasma strains and 6 L-phase variant strains. Values obtained correlated well with the results of other investigators.     

Isolation, Composition, and Structure of Membrane of Listeria monocytogenes

The plasma membrane of Listeria monocytogenes strain 42 was prepared by osmotic lysis of protoplasts with tris(hydroxymethyl)aminomethane (Tris) buffer, pH 8.2, containing MgCl₂ and glucose, followed by washing with NaCl and MgCl₂ in Tris buffer. Electron microscopy showed that the preparation was not contaminated with cytoplasmic material. The membrane preparation was composed of 55 to 60% protein, 1.5% ribonucleic acid, 0.1% deoxyribonucleic acid, 1.3 to 2.3% carbohydrate, 0.17 to 0.38% amino sugar, 0.2 to 0.4% rhamnose, 3.5 to 4.0% phosphorus, 10.5 to 12.0% nitrogen, and 30 to 35% lipid. Amino acid composition of the washed membrane showed some variation from that of the whole cells. Sulfur-containing amino acids were not present in the membrane hydrolysate. The membrane carbohydrate contained glucose, galactose, ribose, and arabinose. The membrane lipid was 80 to 85% phospholipid and 15 to 20% neutral lipid. The lipid contained 2.3 to 3.0% phosphorus, 2.5 to 3.0% carbohydrate, and a very small amount of nitrogen (0.2 to 0.3%). The phospholipid was of the phosphatidyl glycerol type. Electron micrographs of the washed membrane showed three layers. The outer and inner layers varied in thickness from 25 to 37 A and the middle layer from 20 to 25 A. The total thickness varied between 85 and 100 A. These preparations contained many vesicles which stained heavily with lead citrate. Some vesicles were also attached to the protoplast ghosts in the form of extrusions or intrusions, or both. Membrane preparations obtained by lysis of protoplasts in the absence of MgCl₂ were fragmented and contained less lipid (20 to 22%) and ribonucleic acid (0.3 to 0.5%) than preparations prepared with MgCl₂.     

Survey of the U.S. Gulf Coast for the Presence of Clostridium botulinum

In sediments and animals collected during warm weather months between Key West, Fla., and Brownsville, Tex., Clostridium botulinum, predominantly type E, was demonstrable. Incidence was somewhat higher in the eastern Gulf animals, but the organism was present to the southernmost limits of both Texas and Florida. Types A and F were never detected in warm weather. No bottom type or any single species seemed exclusively vulnerable. In samples collected during colder weather, the east-west incidence differential was minimized in animals but not in sediments, overall incidence was lowered, all known types were present, and type E no longer predominated. Detection by fluorescent-antibody techniques was found to be inadequate.     

Cervical Traction in the Home

The indications for and contraindications to cervical traction are discussed. The social and economic advantages to be obtained from carrying out such treatment at home are obvious. A special technique is described which does not make use of weights and in which traction is applied in a position of flexion rather than of extension.     

Protein carboxyl methyltransferase activity specific for age-modified aspartyl residues in mouse testes and ovaries: Evidence for translation during spermiogenesis

An antiserum prepared against the purified protein carboxyl methltransferase (PCMT) from bovine brain has been used to compare testicular and ovarian levels of the enzyme and to study the regulation of PCMT concentrations during spermatogenesis. The PCMT, which specifically modifies age-damaged aspartyl residues, is present at a significantly higher concentration in mature mouse testis than in ovary. However, the PCMT is present at nearly equal concentrations in extracts of germ cell-deficient ovaries and testes obtained from mutant atrichosislatrichosis mice. In normal testis, the concentration of the PCMT increases severalfold during the first 4–5 weeks after birth, paralleling the appearance and maturation of testicular germ cells. Both immunochemical and enzymatic measurements of PCMT specific activities in purified spermatogenic cell preparations indicate that PCMT levels are twofold and 3.5-fold higher in round spermatids and residual bodies, respectively, than in pachytene spermatocytes. The results are consistent with the enhanced synthesis and/or stability of the PCMT in spermatogenic cells and with the continued translation of the PCMT during the haploid portion of spermatogenesis. The relatively high levels of PCMT in spermatogenic cells may be important for the extensive metabolism of proteins accompanying spermatid condensation or for the repair of damaged proteins in translationally inactive spermatozoa.