Identification of two subtypes in the rat type I angiotensin II receptor.

A rat adrenal cDNA library was screened by colony hybridization using a rat cDNA fragment of type I angiotensin II receptor (AT1A) previously isolated from the kidney. Two cDNA clones were identified, designated as AT1B, to have a nucleotide sequence highly homologous to and yet distinct from AT1A. The amino acid sequence of AT1B consists of 359 amino acid residues and has 96% identity with AT1A. No conspicuous difference in the ligand binding characteristics was observed between AT1A and AT1B. The mRNA for AT1B was expressed in many tissues as is the case with AT1A, and most abundantly expressed in the adrenal glands in the Sprague-Dawley rats. The existence of two subtypes in the rat type I angiotensin II receptor might explain the diverse actions of angiotensin II in various tissues.     

New Plasmid-Mediated Phosphorylation of Gentamicin C in Staphylococcus aureus

A clinical isolate of Staphylococcus aureus resistant to gentamicin, kanamycin and 3′,4′-dideoxykanamycin B contained two enzymes capable of inactivating gentamicin, i.e., an aminoglycoside 2″-phosphotransferase and aminoglycoside acetyltransferase.     

Sequence-dependent hydrolysis of RNA using modified oligonucleotide splints and RNase H

To cleave RNA molecules using RNase H in a site-specific manner, a short deoxyoligonucleotide (3-5mer) joining with 2'-O-methyl oligonucleotide(s) was designed as a DNA splint to be used. Model experiments were carried out using ribooligonucleotide substrates (9 and 18 mer). It was found that the use of this type of splints (9 mer) causes a unique cleavage by RNase H. For example, when 3'm (GA)d(AGAA)m(GGU)5' was used as a hybridization strand, 32pUCUUUCUUCUUCCAGGAU was cleaved specifically between U11 and C12 to yield 32pUCUUUCUUCUU. This method will have a variety of applications for the study of RNA.     

A new solid-phase synthesis of oligoribonucleotides by the phosphoro-p-anisidate method using tetrahydrofuranyl protection of 2''-hydroxyl groups.

Six nonaribonucleotides containing the 5'-splice site, one complementary nonamer and an octadecamer containing the 3'-splice site have been synthesized on a polymer support using the phosphoro-p-anisidate method. A 5'-linked 2'-O-tetrahydrofuranyl-N-protected nucleoside 3'-(o-chlorophenyl)phosphoro-p-anisidate was used as the starting nucleotide, and the chain elongated in the 3'-direction by removing the p-anisidate protecting group with isoamyl nitrite under neutral conditions. The octadecamer has been synthesized using dinucleotide blocks and a 3'-terminal trinucleotide.     

Demonstration by light and ultrastructural immunoperoxidase study of alpha-fetoprotein-positive non-hepatoma cells and hepatoma cells during 3'-methyl-4-dimethylaminoazobenzene hepatocarcinogenesis

Immunoreaction of alpha-fetoprotein (AFP) has been described in cholangiolar "oval" cells in the early stage of 3'-methyl-4-dimethylaminoazobenzene hepatocarcinogenesis. The subcellular location of AFP in the oval cells was in the perinuclear space, rough endoplasmic reticulum and Golgi apparatus. In livers with hyperplastic nodules there were two different types of foci containing AFP-positive cells. One type had a normal nucleocytoplasmic ratio and was seen in well-preserved hepatic trabecular structures, and the other had less cytoplasm and occurred in trabecular structures in disarray. AFP-immunoreactivity in the former type was visible in the perinuclear space and rough endoplasmic reticulum but scarce in the Golgi apparatus, and in the latter type it was present in the proliferative smooth endoplasmic reticulum and in several parts of Golgi apparatus in the submembranous or pericanalicular areas. In livers with hepatocarcinoma, AFP immunoreaction was detected in well-differentiated hepatocellular carcinomas, and the subcellular location of AFP was in the perinuclear space, rough endoplasmic reticulum and many developed Golgi complexes. Therefore, AFP-positive cells in livers with hyperplastic nodules are a new cell population in hepatocarcinogenesis, and each type is morphologically different from the oval cell.     

T cells subsets responsible for clearance of Sendai virus from infected mouse lungs

T cell subsets responsible for clearance of Sendai virus from mouse lungs determined by adoptive transfer of immune spleen cell fractions to infected nude mice. T cells with antiviral activity developed in spleens by 7 days after intranasal infection. Spleen cell fractions depleted of Lyt-2+, Lyt-1+, or L3T4+ cells showed antiviral activity in vivo, although the degree of the activity was lower than that of control whole spleen cells. The antiviral activity of the Lyt-2+ cell-depleted fraction was consistently higher than that of L3T4+ (Lyt-1+)-depleted cells. In vitro cytotoxic activity against Sendai virus-associated, syngeneic lipopolysaccharide-blast cells was detected in stimulated cells from intraperitoneally immunized mice but was lost after depletion of Lyt-2+ cells. Multiple injection of anti-Sendai virus antibody into infected nude mice had no effect on lung virus titer. These results indicate that L3T4+ (Lyt-1+) and Lyt-2+ subsets are cooperatively responsible for efficient clearance of Sendai virus from the mouse lung.     

Clinical studies on cell-mediated immunity in patients with renal cell carcinoma: interleukin-2 and interferon-γ production of lymphocytes

Summary The authors examined interleukin-2 (IL-2) production and interferon (IFN) production of peripheral blood mononuclear cells in 28 patients with renal cell carcinoma and 17 control subjects. The peripheral blood was obtained prior to the initiation of therapeutic procedures. The patients were divided into two groups according to tumor size, 5 cm and >5 cm. The production of IL-2 and IFN was measured by immunoradiometric assay. As a result, in the patients with tumors >5 cm, IL-2 and IFN production was impaired. However, in the patients with tumors 5 cm, IFN production was enhanced, though IL-2 production was not significantly different from that of the control subjects. There was no significant correlation between IL-2 production and IFN production.     

Incomplete proviral genome of mouse mammary tumour virus is present on chromosome Y of NIH Swiss and some genetically related mouse strains.

An incomplete proviral genome of endogenous mammary tumour virus (MMTV) was found in DNA of several strains of mice. This MMTV-related sequence was assigned to the Y chromosome since it was clearly observed in male mice only. This MMTV provirus contained a sequence related to LTR (long terminal repeat), but not to gag-pol and env genes. NFS, NIH Swiss/S, STS/A, and DD/Tbr mice have this sequence but BALB/cHeA, SHN, SLN, C57BL/6NJcl, C3H/HeNJcl and CBA/JJcl mice are negative. In the strains containing this sequence, a DNA test for the sequence makes it possible to easily distinguish the DNAs of male or female mice.     

Nalidixic acid-resistant mutations of the gyrB gene of Escherichia coli

Summary DNA fragments of 3.4 kb containing the gyrB gene were cloned from Escherichia coli KL-16 and from spontaneous nalidixic acid-resistant mutants. The mutations (nal-24 and nal-31) had been determined to be in the gyrB gene by transduction analysis. Nucleotide sequence analysis of the cloned DNA fragments revealed that nal-24 was a G to A transition at the first base of the 426th codon of the gyrB gene, resulting in an amino acid change from aspartic acid to asparagine, and nal-31 was an A to G transition at the first base of the 447th codon, resulting in an amino acid change from lysine to glutamic acid. This indicates that mutations in the gyrB gene are responsible for nalidixic acid resistance.