Characterization of erythromycin resistance in Campylobacter jejuni and Campylobacter coli

The mechanism of resistance to erythromycin, the drug of choice in the treatment of campylobacter gastroenteritis, was investigated. Erythromycin resistance (MICs, greater than 1,024 micrograms/ml) in three clinical isolates of Campylobacter jejuni and one C. coli isolate was determined to be constitutive and chromosomally mediated. In vivo protein synthesis in erythromycin-susceptible C. jejuni and C. coli strains was completely inhibited by low levels of erythromycin (5 micrograms/ml), whereas a high concentration of the antibiotic (100 micrograms/ml) had no effect on protein synthesis in erythromycin-resistant strains. Biological assays showed that extracellular degradation of erythromycin was not responsible for erythromycin resistance in strains of Campylobacter species. The rates and amounts of uptake of [14C]erythromycin by resistant and susceptible campylobacter cells were determined to be similar. Binding assays with purified campylobacter 70S ribosomes as well as 50S ribosomal subunits showed that those from erythromycin-resistant strans bound much less [14C]erythromycin than did those from susceptible strains. Genomic DNA from C. coli UA585 was used to transform erythromycin resistance to C. coli UA417. The erythromycin resistance marker was associated with a 240-kb SmaI fragment of the C. coli UA585 genome. Our results rule out erythromycin inactivation or efflux and are not consistent with the production of an RNA methylase, although they are consistent with a mutational mechanism of resistance due to a change in a ribosomal protein gene. This study constitutes a detailed biochemical and genetic characterization of erythromycin resistance in Campylobacter species.

[Autologous bone marrow transplantation in acute myeloid leukemias: a report of 7 cases]

Seven patients with acute myeloid leukemias (AML) in complete remission (CR) were treated with high dose chemotherapy and/or total body irradiation (TBI) followed by autologous bone marrow transplantation (ABMT). The clinical status of the 7 cases at ABMT were as follows: 5 in CR1 (2 with standard risks and 3 with high risks) and 2 in CR2 (both with standard risks). The conditioning regimens used for ABMT were cyclophosphamide plus TBI in 3 cases, high dose busulfan plus cyclophosphamide in 3 cases, and BACT program chemotherapy in 1 case. All 7 cases showed hemopoietic reconstitution after ABMT; no death occurred within the post-transplantation aplasia period, but hepatotoxicity was observed with high dose busulfan. Up to December, 1989, 2 patients in CR1 with standard risk receiving transplants had survived, disease free, for 26 and 18 months, respectively; one of 2 patients in CR2 with standard risk receiving transplants had survived for 30 months, and the other died at the 9th month after ABMT with no sign of leukemia relapse. Two of the 3 patients with high risk relapsed at 5 months post-ABMT and the third was in continuous CR for 5.5 months.

Cmax/AUC is a clearer measure than Cmax for absorption rates in investigations of bioequivalence

In bioequivalence studies, the maximum concentration (Cmax) is shown to reflect not only the rate but also the extent of absorption. Cmax is highly correlated with the area under the curve (AUC) contrasting blood concentration with time. Therefore, use of the Cmax/AUC ratio is recommended for assessing the equivalence of absorption rates. The ratio is independent of both intrasubject variations and possible differences in the extent of absorption and reflects only the contrast between the absorption and disposition rate constants (ka/k).

Sizing and mapping of the genome of Campylobacter coli strain UA417R using pulsed-field gel electrophoresis

Agarose-immobilized chromosomal DNA from the nalidixic-acid-resistant Campylobacter coli strain UA417 and its streptomycin-resistant (StrR) derivative, UA417R, were digested with the restriction enzymes SalI (GTCGAC) and SmaI (CCCGGG). The sizes of the resulting fragments were determined using pulsed-field gel electrophoresis. The two genomes showed similar restriction patterns of seven and 13 fragments for the two respective enzymes and the total genome size was determined to be approx. 1.7 Mb. Analysis of partial digestion fragments, as well as Southern-blot hybridization, were used to construct a physical map of the C. coli UA417R genome. Natural transformation studies using DNA fragments extracted from UA417R, as well as the erythromycin-resistant (EryR) C. coli strain UA585, were used to locate the StrR and EryR resistance markers on the genomic map.

Pulsed-field gel electrophoresis of Campylobacter jejuni and Campylobacter coli genomic DNA and its epidemiologic application

Genomic DNA from 12 different Campylobacter jejuni and 10 Campylobacter coli isolates was digested with SmaI and analyzed by pulsed-field gel electrophoresis (PFGE) and 16S rRNA hybridization studies. Although the two Campylobacter species displayed species-specific restriction and hybridization patterns, significant intraspecies differences were observed. Combined PFGE and hybridization pattern analysis failed to provide any more epidemiologic information than was obtained from PFGE restriction profiles alone. Therefore, results from these studies indicate that PFGE analysis of SmaI-restricted genomic DNA provides a reliable means of differentiating C. jejuni from C. coli and may represent a more practical approach to epidemiologic studies than combining conventional DNA restriction digestion pattern with RNA hybridization procedures.

[Original botanical statistics and commercial study of the Chinese drug touguchao]

According to original botanical statistics, there are 42 species and 5 varieties belonging to 20 families called or used as Touguchao. Commercial investigation shows that 16 species belonging to 12 families are presently available on the market in China.

Mapping of transfer and H pilus coding regions of the IncHII plasmid pHH1508a

The IncHII plasmid pHH1508a (208 kilobases) encodes resistance to potassium tellurite, trimethoprim, and streptomycin. Conjugative pili encoded by pHH1508a were isolated, purified, and used for preparation of anti-H pilus antiserum. Immuno-gold labelling experiments using H pilus specific antiserum showed that antigenic determinants were located along the entire length of the H pilus. Immuno-gold labelling and lysis studies using pilH alpha, a bacteriophage specific for H pili, were used to investigate transfer-deficient mutants of pHH1508a obtained by Tn5 mutagenesis and an in vitro constructed derivative of 96 kilobases, pDT1178, which also conferred resistance to potassium tellurite, trimethoprim, and streptomycin. The transfer-deficient mutants did not specify H pili, whereas pDT1178, which transferred at low frequency (1 x 10(-4) transconjugants per recipient), specified a small number of H pili. A naturally occurring plasmid, pMG110, was found to encode the production of H pili, but was completely transfer deficient (less than 1 x 10(-7) transconjugants per recipient). This study suggests that genes required for H pilus production and assembly as well as low level transfer are located separately within the 96-kilobase fragment of pDT1178 and that other genes, located outside this region, are essential for the regulation and full expression of conjugative transfer.

Genetic characterization of kanamycin resistance in Campylobacter coli

The restriction map of plasmid pIP1433 from Campylobacter coli BM2509, isolated in France, was constructed and the location of the kanamycin (Km) and tetracycline (Tc) resistance markers determined using probes for aphA-3 and tetO genes, respectively. These DNA probes were used to study a second Km- and Tc-resistant strain C. coli UA696, isolated in Canada. In this strain, the Km resistance determinant was located in the chromosome. Like pIP1433, the Km resistance determinant in C. coli UA696 specified a 3'-aminoglycoside phosphotransferase of type III whereas the tetO gene was located on a non-transmissible plasmid.

Rabbit articular chondrocytes in soft agar are useful to test the effect of non-steroidal anti-inflammatory drugs on chondrocyte replication

The effect of non-steroidal anti-inflammatory drugs (NSAIDs) on rabbit articular chondrocyte proliferation was examined in soft agar and in conventional cultures on plastic dishes. Indomethacin, acetylsalicylate, and naproxen (10(-4) M) decreased the efficiency of colony formation by chondrocytes in soft agar in the presence of fibroblast growth factor, although the drugs had little effect on the proliferation of chondrocytes on plastic dishes. On the other hand, tiaprofenic acid (10(-4) M) did not have any adverse effect on chondrocyte replication in either culture the two systems. Rabbit articular chondrocyte growth in soft agar will be a useful test system for examining the effects of anti-arthritic drugs on cartilage metabolism and repair.

Characterization of transfer regions within the HII incompatibility group plasmid pHH1508a

A circular map of the 208-kilobase IncHII plasmid pHH1508a was constructed by using the restriction endonucleases XbaI, XhoI, and NotI. Tn5 insertion mutagenesis showed that transfer genes were distributed widely over the plasmid map. Analysis of the deletion mutant pDT1178 indicated that genes required for conjugative pilus production are located in a 96.0-kilobase region of the plasmid.

The study and clinical application of the osteocutaneous flap of fibula

In this article, four cases of free fibular osteocutaneous flap transfer are reported. The advantages of the bone-attached flap, its microsurgical anatomy, and its design and method of isolation are discussed in detail. Postoperative follow-up showed success in all four cases with satisfactory functional recovery.

Comparison of physiological responses to hypoxia at high altitudes between highlanders and lowlanders

This report deals with the differences and changes of physiological functions of the highlanders and the lowlanders at different altitudes during the period when the Chinese Mountaineering Team was climbing up and reached the peak of Qomolangma Feng. In a period of relaxation, there are no significant changes in ventilatory responsiveness to hypercapnia, electrocardiogram and electroencephalogram between highlanders and lowlanders with the changes at different altitudes. At 5,000 m a.s.l., however, electrocardiogram and the result of cardiac ventricular functional test show significant differences after the subjects are physically loaded. Those whose electrocardiogram readings show unusual changes, and whose cardiac ventricular functional tests show their physiological functions at low degree after physical activities at the altitude of 5,000 m, have a climbing ability hardly below 6,500 m, while those who have reached the altitudes above 8,200 m have no unusual changes in electrocardiogram, and the results of cardiac ventricular functional tests show that their physiological functions are at high degree.