Dihydrofolate reductase gene expression characterized by the PCR assay in human leukemia cells

A modified enzymatic amplification (PCR) method has been used to detect overexpression of the dihydrofolate reductase gene in human leukemic cells resistant to methotrexate (MTX) from both patient samples and cell lines in culture. Quantitation of DHFR mRNA by the PCR assay has been demonstrated to be more accurate and more sensitive than Northern blotting. This assay be useful in screening patients relapsing with drug resistance.

Cyclosporin A suppresses cisplatin-induced oncogene expression in human cancer cells

Most cancer chemotherapeutic agents are designed to damage DNA directly or indirectly. One mechanism of cellular resistance to these agents is enhanced DNA repair. Human ovarian carcinoma cells resistant to cisplatin (A2780DDP) respond to cisplatin treatment with a 3-6-fold increase in gene expression for oncogenes, DNA repair enzymes and enzymes necessary for the synthesis of thymidine. Cyclosporin A has been shown to reverse drug resistance, but its mechanism of action is unclear. In this study, weekly exposures of A2780DDP cells to cyclosporin A resulted in the evolution of a revertant cell line A2780DDP/CSA that was sensitive to cisplatin again and suppressed the induction of genes necessary for the repair of drug-induced DNA damage.

Diminished superoxide production of synovial fluid neutrophils in patients with rheumatoid arthritis following piroxicam treatment

Superoxide production by polymorphonuclear leukocytes (PMNs) and macrophages was inhibited by piroxicam and other non-steroidal anti-inflammatory drugs both in vitro and in vivo. Hitherto, data have only been available on blood PMNs and macrophages. In order to investigate the situation in the joint, PMNs were isolated from synovial fluid before and after 24 h of piroxicam treatment in patients with rheumatoid arthritis. Isolated PMNs were stimulated with PMA and serum-treated zymosan. The capacity of synovial fluid PMNs to produce superoxide decreased by 30% after piroxicam treatment. A similar decrease was found for blood PMNs. No difference in superoxide production was found between blood PMNs and synovial fluid PMNs which were obtained simultaneously. From the fact that the piroxicam concentration in synovial fluid was 40% of the serum value, it can be concluded that piroxicam probably became bound to PMNs before they entered the joint cavity. These results indicate that at the site of the inflammation the superoxide production by PMNs is inhibited by piroxicam treatment. The inhibition of superoxide production is probably important in the effect of piroxicam and other non-steroidal anti-inflammatory drugs in rheumatoid arthritis.

[The blocking and partial agonistic actions of jatrorrhizine on alpha-adrenoceptors]

Jatrorrhizine (Jat) competitively antagonised the effects of phenylephrine on rabbit aortic rings and clonidine on electrically stimulated rat vas deferens with pA2 values of 5.73 and 5.86, respectively. It (5 mg/kg iv) also diminished the pressor responses induced by either thoracic sympathetic stimulation (T7-T9) or noradrenaline (2 micrograms/kg iv) in pithed rats. Furthermore the dose-response curves for methoxamine and B-HT 920 were shifted parallely to the right by iv Jat 10 mg/kg. Below 1 mumol/L, Jat alone showed the depression of the contraction of rat vas deferens stimulated electrically. This effect, however, was less evident at higher concentrations of Jat and was reversed by yohimbine (0.1 mumol/L). Similarly, at very low concentration (1 nmol/L), Jat shifted the dose-response curves for clonidine parallely to the left. In pithed rats, the increase of heart rate evoked with electrical stimulation of spinal segment (C7-T1) was attenuated by Jat (1 mg/kg) and clonidine (30 micrograms/kg), but argumented by large doses of Jat (10 mg/kg) and yohimbine (50 micrograms/kg). The above results showed that: firstly, Jat has blocking actions on both alpha 1- and alpha 2-adrenoceptors, which may be relevant to its hypotensive and anti-arrhythmic actions; secondly, the demonstration of dualistic actions of Jat on adrenoceptors, which has never been documented before, may be also present in other homologues of the protoberberines.

RFLP analysis of HLA-DR beta and -DQ beta genes in the Korean patients with insulin-dependent diabetes mellitus

Human genomic DNA samples from 19 Korean patients and 31 controls of known serological DR antigen specificity were studied for insulin-dependent diabetes mellitus (IDDM)-associated variation in HLA-DR beta and -DQ beta restriction fragment length polymorphisms (RFLPs). Genotyping allowed for accurate assignment of HLA-DR types. For HLA-DRw6, a 12kb/DR beta/Taq I fragment was decreased in Korean IDDM (p less than 0.05). However, we could not find an increased frequency of a 12kb/DQ beta/Bam HI fragment or decreased frequency of a 3.7kb/DQ beta/Bam HI fragment in Korean IDDM. These results suggest a possible protective role of the HLA-DRw6 specificity in IDDM, irrespective of ethnic background, the absence of a specific DQ beta RFLP pattern associated with IDDM in Koreans, and the difference of the Korean population in the genetic of IDDM, compared to the Caucasoid population.

Complement (C3) metabolism in rheumatoid arthritis in relation to the disease course

Metabolic turnover studies of the third component of complement, C3, were performed in 23 patients with rheumatoid arthritis (RA) to get a direct insight in the dynamics of complement synthesis and catabolism. Results of these turnover studies were related to the serum level of the total amount of C3 as well as to that of the activation product C3d. A hypercatabolism of C3 was observed in 12 of the 23 patients studied. Six of these 12 patients showed signs of extra-articular RA; only one patient with extra-articular manifestations had a normal catabolism of C3. Decreased serum levels of C3 were not found in any of the patients with a hypercatabolism of C3, indicating that the accelerated turnover was compensated by an increased synthesis. In RA patients levels of the activation product C3d could not correlate with the turnover of C3. However, in selected RA patients without signs of nodules or extra-articular manifestations, they could. Thus, our results indicate that serum levels of C3 and C3d do not reflect C3 metabolism in RA patients. Furthermore, the existence of extra-articular manifestations is accompanied by a more pronounced activation of the complement system.

An analysis of the levels of complement components in the synovial fluid in rheumatic diseases

A linear relationship between the synovial fluid to serum concentration ratios and log molecular weight was found for six plasma proteins, which are largely synthesized by the liver. Production or utilization of a given protein in the joint can, therefore, be determined by its deviation from the calculated diffusion line. Based on this diffusion model the role of the complement system was investigated in the joint effusions of 48 patients with rheumatoid arthritis (RA), 6 patients with osteoarthritis (OA) and 7 patients with meniscus lesions (ML). Among these three groups quantitative differences were found in the metabolism or utilization of several complement components, based on the fact that the ratios were lower than expected for diffusion of proteins of similar molecular weight. The ratios for the RA group were the lowest. In the three patient groups, results showed increased consumption mainly of C3 and C4 locally in the joint. The existence of a real complement activation in the joints of the three different patient groups was further proved by the elevated levels of C3 breakdown products (C3d). Overall this kind of calculation provides us with a method for studying the role of other proteins which may be important in the inflammatory process of the joint.

HLA and insulin-dependent diabetes mellitus in Koreans

Specific allelic associations vary among ethnic groups. We studied the distribution of HLA-A, -B, -C and -DR antigens in 41 patients with insulin-dependent diabetes mellitus (IDDM) and 280 unaffected persons in Korea. HLA typing was performed by the standard microlymphocytotoxicity test using antisera supplied by the Third Asia-Oceania Histocompatibility Workshop Conference (3rd AOHWC, 1986). There was no association between HLA-A, -B, or -C and IDDM. However, the frequencies of HLA-DR3 and HLA-DR4 were increased in the patients as compared with the controls (19.5% vs 4.3%, RR 5.4, corrected p < 0.005 for DR3 and 61.0% vs 36.4%, RR 2.7, corrected p < 0.05 for DR4). Also a decreased frequency of HLA-DR2 was found in the patients with IDDM (9.8% vs 32.1%, RR 0.3, corrected p < 0.05). These results emphasize the differences in HLA-IDDM associations among different ethnic groups.

The chromosome constitution of plants derived from pollen of hexaploid triticale X common wheat F1 hybrids

The anthers of three F1 hybrids of hexaploid triticale and common wheat ('Rosner' X 'Kedong 58', 'Beagle' X 'Kedong 58' and 'Beagle' X 'Jinghua No. 1') were cultured on four media in vitro. More than 900 green plants were obtained. The chromosome numbers ranged from 17 to 27 for haploid derivatives and from 38 to 52 for diploid regenerates. The chromosome constitutions of the pollen plants reflect those of the gametes found in the donor plants (genome formula: AABBDR). The value of such pollen plants for genetical analysis of rye wheat addition and substitution lines, as well as for breeding purposes, is discussed.

Spirocerca lupi (Rudolphi, 1809) nodule in the rectum of a dog from Connecticut

A small nodule causing repeated rectal prolapse was surgically removed from a four year old Dachshund residing for her entire life in Connecticut. Histologic examination of the biopsy specimen revealed sections of Spirocerca lupi (Rudolphi 1809) surrounded by a granulomatous reaction and fibrous wall.