Correction of chromosomal point mutations in human cells with bifunctional oligonucleotides.

A sequence-specific genomic delivery system for the correction of chromosomal mutations was designed by incorporating two different binding domains into a single-stranded oligonucleotide. A repair domain (RD) contained the native sequence of the target region. A third strand-forming domain (TFD) was designed to form a triplex by Hoogsteen interactions. The design was based upon the premise that the RD will rapidly form a heteroduplex that is anchored synergistically by the TFD. Deoxyoligonucleotides were designed to form triplexes in the human adenosine deaminase (ADA) and p53 genes adjacent to known point mutations. Transfection of ADA-deficient human lymphocytes corrected the mutant sequence in 1-2% of cells. Neither the RD or TFD individually corrected the mutation. Transfection of p53 mutant human glioblastoma cells corrected the mutation and induced apoptosis in 7.5% of cells.     

Cytology of tracheobronchial amyloidosis

Localized amyloidosis of the respiratory tract is seldom diagnosed in cytologic specimens. This report describes a case of the tracheobronchial form of amyloidosis in which diagnostic material was present in a cytologic specimen obtained during bronchoscopy.     

The physical mapping of bacteriophage T5 transfer tRNAs.

Transfer RNAs, isolated from Escherichia coli F cells infected with T5 bacteriophage, were charged with radioactive amino acids and used in RNA-DNA hybridization studies to detect and locate T5 tRNA cistrons in the T5 DNA chromosome. Hybridization of 14 3H-aminoacyl-tRNA species, including purified T5 [35S]Met-tRNAm and [35S]Met-tRNAf, to the separated strands of T5+ DNA indicates that most, if not all, of the T5 tRNAs are transcribed from the continuous heavy strand of T5 DNA. Heteroduplex mapping of eight mutant T5 DNA deletions has enabled us to locate and determine the size of these deleted segments. By correlating this information with the presence and absence of specific tDNA sequences in these mutants, as determined by tRNA-DNA hybridization, we were able to define the physical limits of four tDNA-containing loci along the T5 DNA molecule. A physical map for 15 tRNA species examined indicates that the structural genes for these tRNAs are clustered within a segment length of T5 DNA that represents approximately 11.2% of the total wild type T5 DNA. The existence of the deletion mutants indicates that T5 tRNAs are dispensable for T5 replication under the growth conditions and for the host employed.     

Effects of Suanzaorentang on behavior changes and central monoamines

Previously, it was found that the ancient Chinese remedy of Suanzaorentang could be a promising anxiolytic drug (Chen and Hsieh, 1985a, Chen and Hsieh, 1985b). To understand the mechanism of the action of Suanzaorentang, the effects of Suanzaorentang on behavior changes and central monoamines and their metabolites were studied in rats. It was found that Suanzaorentang significantly (1) prolonged the period from the onset of clonic to tonic convulsions induced by pentylenetetrazol or picrotoxin, (2) prolonged the sleep duration induced by hexobarbital, (3) reduced locomotor activity, (4) enhanced the hypomotility induced by alpha-MT, (5) reduced the locomotor stimulation produced by levodopa plus benserazide, and (6) reduced central HVA, VMA, and 5-HIAA, but had no significant effects on central DA, NA, and 5-HT. These facts implied that Suanzaorentang decreased the turnover rate of central monoamines and central catecholaminergic activity.     

Microvascular pressures measured by micropuncture in isolated perfused lamb lungs

To investigate the influence of vasomotor tone and vessel compliance on pulmonary segmental vascular resistance, we determined the longitudinal distribution of vascular pressures in 15 isolated blood perfused lungs of newborn lambs. We measured pulmonary arterial and left atrial pressures and by micropuncture the pressures in 20- to 80-micron-diam subpleural arterioles and venules, both before and after paralyzing the vasculature with papaverine hydrochloride. In five lungs we also determined the microvascular pressure profile during reverse perfusion. In lungs with baseline vasomotor tone, approximately 32% of the total pressure drop was in arteries, approximately 32% in microvessels, and approximately 36% in veins. With elimination of vasomotor tone, arterial and venous resistances decreased to one-fifth and one-half of base-line values, respectively, indicating that vasomotor tone contributed mainly toward arterial resistance. During reverse perfusion, the pressure drop in veins was similar to that in arteries during forward perfusion, suggesting that the compliance of arteries and veins is comparable. We conclude that vascular tone and compliance are important factors that determine the distribution of segmental vascular resistance in lungs of the newborn.