Use of the Deane prosthesis in patients on long-term peritoneal dialysis

The Deane peritoneal prosthesis has been used successfully in the treatment of 21 patients with chronic renal failure who were maintained on peritoneal dialysis for periods of up to 20 months. All patients were dialyzed for 24 hours twice weekly. While the prosthesis was still in place, transplantation was carried out in seven patients and laparotomy in three. The prosthesis was also used temporarily whenever a permanent peritoneal catheter (Tenckhoff''s) failed because of infection; it was used until the signs of infection disappeared, then the permanent catheter could be replaced safely. From a total of 1136 dialyses 36 positive cultures were reported. Clinical peritonitis was found on only four occasions.     

A combined elastic, fibrin and collagen stain

A method is described which demonstrates nuclei, elastic fibers, red blood cells, collagen and fibrin. Nuclei and elastic fibers are stained by a modified Verhoeff's elastic tissue stain which was previously developed and used in the elastic-Masson combination. Both early fibrin and red blood cells are shown by lissamine fast yellow. Mature fibrin, some types of collagen and other cytoplasmic changes are stained by a combination of acid fuchsin, Biebrich scarlet and ponceau 2R, while old fibrin is demonstrated by the collagen stain. This method takes about 1 hr to perform and has the added advantage that several entities are clearly shown in a single slide.     

The murine aromatic hydrocarbon responsiveness locus: a comparison of receptor levels and several inducible enzyme activities among recombinant inbred lines

The aromatic hydrocarbon responsiveness (Ah) locus has been correlated with genetic differences in the risk of drug toxicity, teratogenesis, chemical carcinogenesis, and mutagenesis. Hepatic cytosolic Ah receptor levels, 2-amino-5-chlorobenzoxazole (zoxazolamine) paralysis time following beta-naphthoflavone treatment and aryl hydrocarbon hydroxylase (AHH3, acetanilide 4-hydroxylase (Ac4H), and NAD(P)H:menadione oxidoreductase (NMOR)4, induction by 3-methylcholanthrene were studied in (a) the progenitors C57BL/6J (Ahb/Ahb) and DBA/2J (Ahd/Ahd) and 25 BXD recombinant inbred lines, (b) the progenitors C57BL/6N and C3H/HeN and 14 B6NXC3N recombinant inbred lines, and (c) the progenitors C57BL/6J and C3H/HeJ and 12 BXH recombinant inbred lines. The Ahb phenotype exhibits greater than 5 femtomole receptor/mg of cytosolic protein, less than or equal to 15 minutes zoxazolamine paralysis time, and twofold to 15-fold induction of these three hepatic enzyme activities; the Ahd phenotype exhibits less than or equal to 2 fmol receptor/mg protein, greater than 15 minutes zoxazolamine paralysis time, and less than 30% induction of these three activities. Among the BXD lines but especially among the B6NXC3N and BXH lines, high frequencies of recombination were found; the phenotype of each of the five parameters did not segregate with the phenotype of each of the other parameters in four or more recombinant lines. This report shows for the first time that AHH induction by 3-methylcholanthrene can occur in the Ahd phenotype mouse. These data underline the complexity of this genetic system when genes from C57BL/6 and DBA/2 are combined and particularly when genes from C57BL/6 and C3H/He inbred mouse strains are combined.     

Silicification of developing internodes in the perennial scouring rush (Equisetum hyemale var. affine)

An electron microprobe (EMP) analysis of silica (SiO₂) deposition in the epidermis of developing internodes of the perennial scouring rush (Equisetum hyemale var. affine) indicates that SiO₂ is first detected in the stomatal apparatus beginning with internode 3, then the epidermal papillae (internode 8), and finally in radial cell walls of the long epidermal cells (internode 10). This process is initiated in the intercalary growth regions at the bases of the elongating internodes. The deposition of SiO₂ in long epidermal cell walls occurs after internodal extension has ceased and should therefore be considered as one of the final stages in internodal differentiation that involves strengthening the cellulosic framework of the cell wall. EMP measurements indicate that SiO₂ in stomata is equivalent to 30% of a pure SiO₂ standard and that SiO₂ in the radial walls of long epidermal cells averages twice that measured on the tangential walls of these same cells. This study supports the view that silicification plays a major role in strengthening the developing perennial scouring rush internodal system and that regulation of this process in this and other species of Equisetum, whose SiO₂ deposition patterns are markedly different, deserves further study.     

Paired sequence difference in ribosomal RNAs: evolutionary and phylogenetic implications

Ribosomal RNAs have secondary structures that are maintained by internal Watson-Crick pairing. Through analysis of chordate, arthropod, and plant 5S ribosomal RNA sequences, we show that Darwinian selection operates on these nucleotide sequences to maintain functionally important secondary structure. Insect phylogenies based on nucleotide positions involved in pairing and the production of secondary structure are incongruent with those constructed on the basis of positions that are not. Furthermore, phylogeny reconstruction using these nonpairing bases is concordant with other, morphological data.      

SCANNING ELECTRON MICROSCOPY AND ELECTRON MICROPROBE ANALYSIS OF SILICIFICATION PATTERNS IN INFLORESCENCE BRACTS OF AVENA SATIVA

Using scanning electron microscopy, we determined the kinds and distribution of epidermal cell types in Avena inflorescence bracts (glume, lemma, and palea). Electron microprobe analysis of silica deposition in these epidermal cells showed that silica cells constitute one of the important deposition sites. Probe ratio data indicate that the silica deposited is 74 % pure. Significant amounts of silica also become deposited in the trichomes and lesser amounts in the walls of long epidermal cells. None could be detected in the stomata. The possible functional significance of silica deposition in epidermal cells of these bracts is discussed.