Acquired bilateral naevus of Ota-like macules: an immunohistological analysis of dermal melanogenic paracrine cytokine networks

BACKGROUND

Acquired bilateral naevus of Ota-like macules (ABNOM) is similar to melasma with regard to their clinical features, including female predominance, acquired onset, and predominant involvement of the malar area. The similar clinical features suggest the possibility of a shared pathogenesis. Dermal factors including vascularity and melanogenic paracrine networks such as the stem cell factor (SCF)/c-kit pathway have recently been suggested to play an important role in the pathogenesis of melasma. However, the role of dermal factors in ABNOM remains unknown.

OBJECTIVES

To provide a novel view on the pathogenesis of ABNOM, we studied the expression of melanogenic paracrine cytokines such as SCF/c-kit, and assessed dermal vascularity.

METHODS

Thirty-seven patients with ABNOM and 20 patients with melasma were enrolled in this study. Skin samples were obtained from lesional and perilesional normal skin. Immunohistochemistry was performed.

RESULTS

Solar elastosis was slightly more intense in the lesional skin of ABNOM. In contrast to dermal pigmentation and melanocytes, the amounts of epidermal pigmentation and melanocytes were not increased in the lesional skin of patients with ABNOM. The expression of dermal SCF and c-kit was increased; however, the expression of epidermal SCF and c-kit and dermal factor VIII-related antigen was not increased in the lesional skin of ABNOM.

CONCLUSIONS

These results suggest that the increased expression of the SCF/c-kit pathway between dermal fibroblasts and dermal melanocytes may play an important role in the pathogenesis of ABNOM.

Observations on unaided smoking cessation after deep brain stimulation of the nucleus accumbens

AIMS

We explore whether clinical research on deep brain stimulation (DBS) of the nucleus accumbens (NAc) to treat addiction is justified besides theoretical speculation.

METHODS

Since 2004, 10 patients who were also smokers were treated at the University of Cologne for Tourette's syndrome (TS), obsessive-compulsive disorders (OCD) or anxiety disorders (AD) by DBS of the NAc. We assessed their smoking behavior after DBS and (in retrospection) before by the Fagerstrom Test for Nicotine Dependence (FTND) and additional items.

RESULTS

Three male patients were able to quit smoking after DBS. They were less dependent and higher motivated compared to the rest of the sample. They are stimulated with a higher voltage. During 1-year, 2-year, and 30-month follow-ups, we found a higher rate of successful smoking cessation (20, 30 and 30%) compared to unaided smoking cessation in the general population (13, 19 and 8.7%).

CONCLUSIONS

Albeit the results of the study are severely limited by the method of retrospective self-assessment of psychiatric patients, further research of DBS of the NAc to treat addiction seems justified. In addition to biological mediators, psychosocial factors should be assessed in further prospective studies.

Base excision DNA repair defect in Gadd45a-deficient cells

As one of a number of p53-regulated genes, Gadd45a (growth arrest and DNA damage inducible gene) has been shown to delay carcinogenesis and decrease mutation frequency. Gadd45a is known to regulate nucleotide excision DNA repair (NER) in response to UV radiation. Here, we report an emerging role for Gadd45a in base excision repair (BER). Gadd45a-null mouse embryo fibroblasts MEF and gadd45a-deficient human colon cancer cells exhibited slow BER after treatment with methyl methanesulfonate (MMS) a pure base-damaging agent. In addition, removal of AP sites by apurinic/apyrimidinic endonuclease 1/redox factor 1 (APE1/Ref1) was significantly delayed in gadd45a-null cells. Moreover, the localization of APE1/Ref1 within the nucleus was observed in gadd45a wild-type cells, whereas APE1 become mainly distributed in the cytoplasm, and there is a reduced interaction with proliferating cell nuclear antigen (PCNA) in Gadd45a-deficient cells. Inasmuch as p53 has been shown to regulate BER in addition to the NER pathway, our data suggest that p53-regulated gene Gadd45a contributes to the BER response by affecting the interaction of cellular APE1/Ref1 with PCNA. Gadd45a might be a key component gene of the p53 pathway involved in protection from carcinogenic base damage and maintenance of genomic stability, although the downstream mechanism including APE1/Ref1 will need further study.

Exclusive measurement of the nonmesonic weak decay of the lambda(5)He hypernucleus

We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay of lambda(5)He formed via the 6Li(pi+, K+) reaction. The energies of the two nucleons and the pair number distributions in the opening angle between them were measured. In both np and nn pairs, we observed a clean back-to-back correlation coming from the two-body weak reactions of lambda p --> np and lambda n --> nn, respectively. The ratio of the nucleon pair numbers was N(nn)/N(np) = 0.45 +/- 0.11(stat) +/- 0.03(syst) in the kinematic region of cos theta(NN) < -0.8. Since each decay mode was exclusively detected, the measured ratio should be close to the ratio of gamma(lambda p --> np)/gamma(lambda n --> nn). The ratio is consistent with recent theoretical calculations based on the heavy meson and/or direct-quark exchange picture.

Barriers to the use of a personal health record by an elderly population

Personal health records(PHRs) are proposed as a strategy to make health care delivery increasingly patient-centered. Yet little work has been done in understanding the workflows of patients in their own homes, or influence of access, cognitive, physical, or literacy barriers on workflow and outcomes of using health records. Many populations may require assistance in using PHRs to improve their health out-comes. We studied PHR use by an elderly and disabled population and describe those barriers encountered by our patients.

An electron microbeam cell-irradiation system at KIRAMS: performance and preliminary experiments

An electron microbeam cell-irradiation (EMCI) system is now ready for routine operation in Korea. The system components include an electron gun operating at 1-100 keV, a beam transport chamber delivering a micron-sized beam, a cell image acquisition and positioning part and an automatic system control section. The present choice of source beam energy is 30 keV so that the radiation impact is conveyed to the targeted cells with a minimum spatial dispersion. The beam is available at 5 microm in diameter now, but can be changed in the range of 1-200 microm. The cellular dose is delivered with a standard deviation of 30% at 0.1 Gy, 10% at 1 Gy and 3% at 10 Gy. The cells are recognised by over 98% in a 1 mm x 1 mm area and the system is capable of irradiating up to 30,000 cells h(-1).

Electron track simulation using ETMICRO

A new Monte Carlo code ETMICRO (Electron Transport code for MICROdosimetry) is now available for tracing the electrons down to 10 eV in liquid water. ETMICRO employs much the same frame of track construction as the previous programs except that the plasmon excitation is left out of consideration and thus there is no delocalisation of energy deposition. The inverse mean free path data and the corresponding differential values (DIMFPs) were prepared by adopting the Drude model parameters that were derived from a new optical data set for liquid water. The potential of electrons causing direct damage on DNA has been estimated as functions of the energy of electrons and their distance from DNA in an arbitrary direction.

Beam characterisation of the KIRAMS electron microbeam system

An electron microbeam system has been installed at the Korea Institute of Radiological and Medical Sciences (KIRAMS) for use in radiation biology studies. The electron beam is produced from a commercial electron gun, and the beam size is defined by a 5 microm diameter pinhole. Beam energy can be varied in the range of 1-100 keV, covering a range of linear energy transfer from 0.4 to 12.1 keV microm-1. The micrometer-sized electron beam selectively irradiates cells cultured in a Mylar-bottomed dish. The positioning of target cells one by one onto the beam exit is automated, as is beam shooting. The electron beam entering the target cells has been calibrated using a Passivated Implanted Planar Silicon (PIPS) detector. This paper describes the KIRAMS microbeam cell irradiation system and its beam characteristics.

Intercellular adhesion molecule-1 polymorphisms in Korean patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by synovial proliferation and the accumulation of inflammatory cells in the affected joints. Intercellular adhesion molecule-1 (ICAM-1) is readily detected in RA synovial tissues and helps recruit inflammatory cells to the joint. ICAM-1 shows genetic polymorphisms at codons 241 (R241G) and 469 (K469E). In order to investigate the association between ICAM-1 gene polymorphisms and RA, we genotyped ICAM-1 R241G and ICAM-1 K469E polymorphisms in 143 Korean patients with RA, and in 138 healthy controls, by using the polymerase chain reaction-restriction fragment length polymorphism method. No polymorphism of R241G was found in Korean subjects. However, the frequency of the K469 allele was found to be significantly lower in RA patients than in healthy controls. Allele frequency of K469 was lower in RA patient group, compared to that in healthy controls, regardless of the shared epitope status. Distribution of K469E allele frequencies was not different whether the patient had rheumatoid factor, radiographic erosion or extra-articular complications. In conclusion, this study shows lower frequency of the ICAM-1 K469E allele in Korean patients with RA than that in healthy controls.

A microdosimetric approach to the thermal neutron fluence prescription for clinical BNCT

A microdosimetric estimation has been performed to investigate the stochastic variations in doses to the target cell nuclei in boron neutron capture therapy (BNCT). The 9L gliosarcoma cells and the capillary endothelial cells were the targets of our interest. More than 80% of tumour control and less than 50% of myeloparesis incidence were taken as the biological endpoints to be accomplished. Estimation was performed for two major boron carriers, sulfhydryl borane (BSH) and boronophenylalanine (BPA). From the macrodosimetric point of view, the effective thermal neutron fluence in BNCT ranges from 3.96 x 10(12) to 5.17 x 10(12). From the microdosimetric point of view however, the prescription regarding thermal neutron irradiation becomes much more complex. According to the microdosimetric analysis, the difference between the tumour and the normal tissue in BSH or BPA concentration is not large enough to guarantee the 80% control of 9L gliosarcoma along with the myeloparesis incidence limited below 50%.

Treadmill exercise increases cell proliferation in hippocampal dentate gyrus in alcohol-intoxicated rats

AIM

Effect of treadmill exercise on hippocampal cell proliferation under normal conditions has been well documented; however, this effect under alcohol intoxication conditions is not clarified, yet. In the present study, the effect of treadmill exercise on cell proliferation in the dentate gyrus in alcohol-intoxicated rats was investigated.

METHODS

EXPERIMENTAL DESIGN

comparative investigation on number of 5-bromo-2'-deoxyuridine (BrdU)-positive cells in the dentate gyrus 8 days after commencement.

SETTING

animal laboratory.

PARTICIPANTS

male Sprague-Dawley rats of 5 weeks in age weighing 150+/-10 g.

INTERVENTION

animals were divided into 4 groups: the control-rest group, the control-exercise group, the alcohol-treated-rest group, and the alcohol-treated-exercise group. Animals of the alcohol-treated groups were injected intraperitoneally with alcohol (2 g/kg) once a day for 3 days. All animals were injected BrdU (50 mg/kg) intraperitoneally, and rats of exercise groups were made to run on treadmill for 30 min each day for 5 days following alcohol administration.

MEASURES

mean number of BrdU-positive cells in dentate gyrus was observed via immunohistochemistry.

RESULTS

Treadmill exercise significantly increased the number of BrdU-positive cells in the dentate gyrus. Also, treatment with alcohol for 3 days inhibited cell proliferation and treadmill exercise alleviated alcohol-induced inhibition of new cell formation.

CONCLUSION

These results suggest the possibility that treadmill exercise may help in improvement following alcohol-induced brain damage.

Successful treatment of bcr/abl-positive acute mixed lineage leukemia by unmanipulated bone marrow transplantation from an HLA-haploidentical (3-antigen-mismatched) cousin

We describe a patient with bcr/abl-positive acute mixed lineage leukemia who successfully underwent transplantation in primary induction failure, using unmanipulated bone marrow from a human leukocyte antigen (HLA)-haploidentical cousin. The tumor burden was successfully reduced by the administration of imatinib mesylate (STI571) before transplantation. As graft-versus-host disease (GVHD) prophylaxis, a combination of tacrolimus and a short course of methotrexate, methylprednisolone, and mycophenolate mofetil was used. Hematopoietic reconstitution was rapid, and acute GVHD was limited to the skin (grade I). The patient is still in complete remission past day +400. This successful case suggests that HLA-haploidentical transplantation using unmanipulated marrow from a distantly related relative can be considered for patients in urgent situations who do not have HLA-identical donors.

Sigma-nucleus potential in A=28

We have studied the (pi(-),K+) reaction on a silicon target to investigate the sigma-nucleus potential. The inclusive spectrum was measured at a beam momentum of 1.2 GeV/c with an energy resolution of 3.3 MeV (FWHM) by employing the superconducting kaon spectrometer system. The spectrum was compared with theoretical calculations within the framework of the distorted-wave impulse approximation, which demonstrates that a strongly repulsive sigma-nucleus potential with a nonzero size of the imaginary part reproduces the observed spectrum.

Auricular acupuncture increases cell proliferation in the dentate gyrus of Sprague-Dawley rats

In a previous study, we have reported that acupuncture increases cell proliferation in the dentate gyrus after transient global ischemia in gerbils. In the present study, the effect of auricular acupuncture (AA) on dentate cell proliferation was examined in appropriately fed and food-deprived adult Sprague-Dawley (S-D) rats. 5-Bromo-2'-deoxyuridine-5'-monophosphate (BrdU) immunohistochemistry revealed a significant increase in cell birth in the dentate gyrus of both groups after AA treatment. In addition, the effect of AA on cell proliferation in the dentate gyrus was more profound in the food-supplied group. These findings demonstrate that AA enhances cell proliferation in the dentate gyrus of adult rats.

Isolation and properties of arginase from a shade plant, ginseng (Panax ginseng C.A. Meyer) roots

Arginase (EC 3.5.3.1) was purified to homogeneity from root tissues of three-year-old ginseng (Panax ginseng C.A. Meyer), shade plant, and was found to be an extraordinarily large molecule relatively stable to heat. The enzyme was decameric having a molecular mass of 352,000 Da, with an optimal temperature and pH of 60 degrees C and 9.5, respectively. Analogues of arginine could not replace it as substrate, and a cysteine residue is at or near the active site. Maximum activity was obtained with Mn(2+) and Co(2+) also activated the proteins, whereas, both agmatine and 5'-deoxy-methylthioadenosine were inhibitors. Specific activities of the enzyme in sliced ginseng roots were increased by plant hormones such as GA(3), IAA, kinetin and putrescine, whereas the activities of the purified enzyme were unaffected by putrescine. Increases in arginase activities by these plant hormones could affect metabolism of polyamine intracellularly.

Protective effects of puerariaeflos against ethanol-induced apoptosis on human neuroblastoma cell line SK-N-MC

Puerariaeflos (PF) is an oriental medical herb for alcohol abuse. To investigate whether PF possesses protective effects against ethanol (EtOH)-induced cytotoxicity in the central nervous system, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometric analysis, DNA fragmentation assay, and reverse transcription-polymerase chain reaction were performed on SK-N-MC human neuroblastoma cells. Cells treated with EtOH exhibited several apoptotic features, while those pre-treated with PF prior to EtOH exposure showed a decreased occurrence of apoptotic features. In addition, PF pre-treatment inhibited the EtOH-induced increase in caspase-3 mRNA expression. These results suggest that PF may exert protective effects against EtOH-induced apoptosis in human neuroblastoma cells.

Caffeine inhibits exercise-induced increase in tryptophan hydroxylase expression in dorsal and median raphe of Sprague-Dawley rats

Effect of caffeine on the expression of tryptophan hydroxylase (TPH), rate limiting enzyme of serotonin synthesis, in dorsal and median raphe was investigated via immunohistochemistry. In exercise groups, Sprague-Dawley rats were put on treadmill running for 30 min per day for 6 consecutive days. On the seventh day, animals of control-with-caffeine group were injected subcutaneously with 4 mg/kg caffeine, while control-without-caffeine group were injected with 0.9% NaCl, sacrificed 2 h later. Exercise-with-caffeine group and exercise-without-caffeine group were injected with caffeine and NaCl, respectively; all-out time was determined 1 h after injection, and then sacrificed. Caffeine increased all-out time in exercised rats, and inhibited the exercise-induced elevation in TPH expression. The suppressive effect of caffeine on TPH expression in exercised rats can be suggested as one possible ergogenic mechanism of caffeine.

Auricular acupuncture decreases neuropeptide Y expression in the hypothalamus of food-deprived Sprague-Dawley rats

The aim of the present study was to investigate whether stimulation of auricular acupuncture point has any effects on the expression of neuropeptide Y (NPY), appetite-inducing factor particularly abundant in the mammalian hypothalamus. In food-deprived condition, enhanced NPY expression was detected in both the arcuate nucleus (ARN) and the paraventricular nucleus (PVN) of the hypothalamus via immunohistochemistry in Sprague-Dawley rats. Needling the unfed rats on the auricular point resulted in decreased NPY levels in both the ARN and PVN, while it increased NPY levels in the ARN and PVN of fed rats. The present findings indicate that auricular acupuncture may affect NPY expression in the ARN and PVN of the hypothalamus.

Assembly and mixing of two-stage aqueous two-phase protein extractions

The effect of the order of system assembly was studied in two-stage aqueous two-phase systems loaded with whole bovine blood and BSA. Recovery in the bottom phase of the back extraction varied by up to 40% depending on the manner in which the forward extraction was assembled, significantly impacting upon the efficiency of the process. The effect of mixing intensity was investigated using a simple shear device. As expected, higher shear rates were found to facilitate mass transfer and shorten the time taken to reach equilibrium. Mixing at lower shear rates for extended periods resulted in a lower recovery of protein.

Anti-atherogenic effect of citrus flavonoids, naringin and naringenin, associated with hepatic ACAT and aortic VCAM-1 and MCP-1 in high cholesterol-fed rabbits

The anti-atherogenic effects of the citrus flavonoids, naringin and naringenin, were evaluated in high cholesterol-fed rabbits. At 3 months of age, 30 male New Zealand White (NZW) rabbits were divided into three groups (n = 10 per group). The rabbits were fed a 1% cholesterol diet alone (control group) or a diet supplemented with either 0.1% naringin or 0.05% naringenin for 8 weeks. The plasma lipoprotein levels, total cholesterol, triglyceride, and high-density lipoprotein showed no significant differences in the control and experimental groups. Hepatic acyl-CoA:cholesterol acyltransferase (ACAT) activity was slightly low in naringin (5.0%)- and naringenin (15.0%)-fed rabbits, compared to control group. The aortic fatty streak areas were significantly lower in both the naringin (19.2 +/- 5.6%)- and naringenin (18.1 +/- 6.5%)-supplemented groups than in the control group (60.4 +/- 14.0%). The expression levels of vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemotactic protein-1 (MCP-1), by semiquantitative RT-PCR analysis of the thoracic aorta, were significantly lower in the flavonoids supplemented groups than in the control group. These results suggest that the anti-atherogenic effect of the citrus flavonoids, naringin and naringenin, is involved with a decreased hepatic ACAT activity and with the downregulation of VCAM-1 and MCP-1 gene expression.

Conductivity of doped two-leg ladders

Recently, conductivity measurements were performed on the hole-doped two-leg ladder material S(r14-x)Ca(x)Cu(24)O(41). In this work, we calculate the conductivity for doped two-leg ladders using a model of hole pairs forming a strongly correlated liquid. Quantum interference effects are handled using renormalization group methods. We find that our model can account for the low-energy features of the experiments. However, at higher energies there are deviations from the predictions of this model. Using the results of our calculations as well as results on the ground state of doped two-leg ladders, we suggest a scenario to explain the experimental results.

Expression of MAGE-1, -2, and -3 genes in gastric carcinomas and cancer cell lines derived from Korean patients

We investigated the expression of MAGE-1, -2, and -3 genes in tissues of 51 gastric carcinomas from Korean patients and in 11 gastric cancer cell lines established in Korea using reverse transcriptase-polymerase chain reaction along with immunohistochemical analyses and DNA sequencing. Among the 51 gastric carcinomas, MAGE-1, -2, and -3 genes were expressed in 16 (31%), 22 (43%), and 17 (33%), respectively, and 31 (60%) expressed at least one of the three genes. In contrast, none of the three MAGE genes were expressed in normal sites of gastric tissue from each cancer patient. Out of 11 gastric cancer cell lines, MAGE-1, -2, and -3 genes were expressed in two (18%), five (46%), and four (36%), respectively. According to the clinicopathological analysis, the expression of any of the three MAGE genes was not significantly correlated with several clinicopathological factors except histologic types (p= 0.067). Immunohistochemical analyses identified positive staining with monoclonal antibodies 77B and 57B specifically against MAGE-1 and -3 proteins, respectively, in nuclei and cytoplasms of cells in mRNA-positive tumor tissue. These findings suggest the possibility as a target for tumor-specific immunotherapy for Korean patients.

Acupuncture increases cell proliferation in dentate gyrus after transient global ischemia in gerbils

The effects of acupuncture on cell proliferation in the dentate gyrus of gerbils after transient global ischemia were investigated in this study. Acupuncture was performed on Zusanli (ST36), which is a well known acupoint in animals and humans. In Oriental medicine, Zusanli has been commonly used for the enhancement of functional recovery in stroke patients. Through 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry, an increase in cell birth in the dentate gyrus of gerbils after ischemic injury was detected. Interestingly, acupunctural treatment in ischemic gerbils resulted in a significant increase in the number of BrdU-positive cells in the dentate gyrus. The present findings indicate that acupuncture may affect cell proliferation in the dentate gyrus of gerbils after ischemic injury.

Immunoglobulin variable-region diversity in the zebrafish

As part of an investigation of the immune system in the developing zebrafish, Danio rerio, we cloned and characterized a genomic V(H) segment and a number of cDNAs encoding IgM heavy chains. The genomic V(H) has the characteristic features of V(H) in other vertebrates, including a leader segment interrupted by a short intron, and regulatory and recombination signal sequences. The V(H) sequences of 75 cDNA clones fell into four distinct groups or families. All of these families cluster most closely with other teleost V(H); one of the families, V(H)3, is also closely related to other vertebrate V(H). Analysis by Southern blotting suggests that there are a number of germline genes corresponding to each family. Most variability within the V(H)1 family is confined to codons 30-32, at the end of the first framework region and in the beginning of the first complementarity-determining region. The nucleotide sequence of the genomic V(H) in this region contains motifs associated with a relatively high frequency of somatic mutation. There is much variability in segments of the clones corresponding to the third complementarity-determining region. The cDNA sequences encoding the fourth framework region are consistent with the contribution of four distinct J(H) segments.

NK-1 receptor desensitization and neutral endopeptidase terminate SP-induced pancreatic plasma extravasation

Substance P (SP) induces plasma extravasation and neutrophil infiltration by activating the neurokinin-1 receptor (NK1-R). We characterized the mechanisms regulating this response in the rat pancreas. Anesthetized rats were continuously infused with SP, and plasma extravasation was quantified using Evans blue (EB) dye. Continuous infusion of SP (8 nmol. kg(-1). h(-1)) resulted in a threshold increase in EB at 15 min, a peak effect at 30 min (150% increase), and a return to baseline by 60 min. The NK1-R antagonist CP-96,345 blocked SP-induced plasma extravasation. After 60 min, the NK1-R was desensitized to agonist challenge. Resensitization was first detected at 20 min and increased until full recovery was seen at 30 min. Inhibition of the cell-surface protease neutral endopeptidase (NEP) by phosphoramidon potentiated the effect of exogenous SP; therefore endogenous NEP attenuates SP-induced plasma extravasation. Thus the continuous infusion of SP stimulates plasma extravasation in the rat pancreas via activation of the NK1-R, and these effects are terminated by both desensitization of the NK1-R and the cell-surface protease NEP.

Structural characterization of beta-D-(1 --> 3, 1 --> 6)-linked glucans using NMR spectroscopy

Nondestructive structural analysis of a series of beta-D-(1 --> 3, 1 --> 6)-linked glucans (laminaran, curdlan, yeast glucan, scleroglucan, etc.) was performed using two-dimensional NMR spectroscopy. The relative ratios of H-1 at different AGUs provided the information about DPn and DB. The alpha-, and beta-anomeric protons on reducing terminals were assigned at 5.02 to approximately 5.03 ppm (J 3.6 to approximately 3.7 Hz), and 4.42 to approximately 4.43 ppm (J 7.6 to approximately 7.9 Hz), respectively, whereas the H-1 protons of internal AGUs and beta-(1 --> 6)-branched AGUs appeared at 4.56 to approximately 4.59 ppm (J 7.6 to approximately 7.8 Hz), and 4.26 to approximately 4.28 ppm (J 7.6 to approximately 10.6 Hz), respectively, in a mixed solvent of 6:1 Me2SO-d6-D2O at 80 degrees C. In the solvent, the OH peaks were eliminated from the spectra allowing the H-1 protons to appear clearly. In addition, the nonreducing terminal H-1 and H-1 at the AGU next to reducing terminal could be assigned at 4.45 to approximately 4.46 ppm (J 7.8 to approximately 7.9 Hz), and 4.51 to approximately 4.53 ppm (J 7.8 Hz), respectively. The DPn of the laminaran was 33 (polydispersity 1.12) and the DB was 0.07. The number of glucosyl units in the side chain of laminaran is more than one. The DPn and DB of the water-insoluble yeast glucan were 228 and 0.003, respectively. However the DPn of water soluble yeast glucan phosphate and curdlan was changed upon the number of freeze-drying processes and the content of water in the mixed solvent, respectively. And the DB of those were calculated as 0.02 and 0, respectively. The DB of scleroglucan was precisely calculated as 0.33, compared with the previously reported data. The H-1s at different AGUs of the various beta-D-(1 --> 3, 1 --> 6)-linked glucans having different DB can be exactly assigned by their chemical shifts in the mixed solvent system. This NMR analysis can be effectively used to determine the DP and DB of polysaccharides in a simple and non-destructive manner.

Substance P is a determinant of lethality in diet-induced hemorrhagic pancreatitis in mice

BACKGROUND

The neuropeptide substance P (SP) induces plasma extravasation and neutrophil infiltration by activating the neurokinin 1-receptor (NK1-R). SP-induced neurogenic inflammation is terminated by the cell surface enzyme neutral endopeptidase (NEP), which degrades SP. We determined whether genetic deletion of the NK1-R reduces mortality and, conversely, whether genetic deletion of NEP increases mortality in a lethal model of hemorrhagic pancreatitis.

METHODS

Necrotizing pancreatitis was induced by feeding mice a diet deficient in choline and supplemented with ethionine. We determined the length of survival, the severity of pancreatitis (by measuring the neutrophil enzyme myeloperoxidase [MPO] and by histologic evaluation), and the severity of pancreatitis-associated lung injury (lung MPO and histology) in NK1-R (+/+)/(-/-) and NEP (+/+)/(-/-) mice.

RESULTS

Genetic deletion of the NK1-R significantly improved survival (100% vs 8% at 120 hours, P <.001) and reduced pancreatic MPO and acinar cell necrosis. Conversely, genetic deletion of NEP significantly worsened survival (0% vs 90% at 120 hours, P <.001) and exacerbated pancreatic MPO and pancreatitis-associated lung injury.

CONCLUSIONS

Substance P is an important determinant of lethality in this model of necrotizing pancreatitis. Defects in NEP expression could lead to uncontrolled inflammation.

A TGF-beta-inducible cell adhesion molecule, betaig-h3, is downregulated in melorheostosis and involved in osteogenesis

Melorheostosis is a rare bone disease characterized by linear hyperostosis and associated soft tissue abnormalities. The skin overlying the involved bone lesion is often tense, shiny, erythematous, and scleodermatous. In order to look for genes differentially expressed between the normal and involved skin, we cultured skin fibroblasts from the skin lesions of several afflicted patients, and identified differentially expressed genes by reverse dot-blot hybridization. We found that the genes human TGF-beta-induced gene product (betaig-h3), osteoblast-specific factor 2, osteonectin, fibronectin, and type I collagen were all downregulated in the affected skin fibroblasts, with betaig-h3 the most significantly affected. The expression of betaig-h3 was induced by TGF-beta in both affected and normal fibroblasts. In an effort to determine the mechanism of bone and skin abnormalities in melorheostosis, we made recombinant betaig-h3. Both immobilized and soluble recombinant betaig-h3 proteins with or without an RGD motif inhibited bone nodule formation of osteoblasts in vitro. Taken together, our results suggest that altered expression of several adhesion proteins may contribute to the development of hyperostosis and concomitant soft tissue abnormalities of melorheostosis, with betaig-h3 in particular playing an important role in osteogenesis.

Human cytotoxic T-lymphocyte responses specific for peptides of the wild-type Wilms' tumor gene (WT1 ) product

The product of the Wilms' tumor gene WT1 is a transcription factor overexpressed not only in leukemic blast cells of almost all patients with acute myeloid leukemia, acute lymphoid leukemia, and chronic myeloid leukemia, but also in various types of solid tumor cells. Thus, it is suggested that the WT1 gene plays an important role in both leukemogenesis and tumorigenesis. Here we tested the potential of WT1 to serve as a target for immunotherapy against leukemia and solid tumors. Four 9-mer WT1 peptides that contain HLA-A2.1-binding anchor motifs were synthesized. Two of them, Db126 and WH187, were determined to bind to HLA-A2.1 molecules in a binding assay using transporter associated with antigen processing-deficient T2 cells. Peripheral blood mononuclear cells from an HLA-A2.1-positive healthy donor were repeatedly sensitized in vitro with T2 cells pulsed with each of these two WT1 peptides, and CD8(+) cytotoxic T lymphocytes (CTLs) that specifically lyse WT1 peptide-pulsed T2 cells in an HLA-A2.1-restricted fashion were induced. The CTLs also exerted specific lysis against WT1-expressing, HLA-A2.1-positive leukemia cells, but not against WT1-expressing, HLA-A2.1-negative leukemia cells, or WT1-nonexpressing, HLA-A2. 1-positive B-lymphoblastoid cells. These data provide the first evidence of human CTL responses specific for the WT1 peptides, and provide a rationale for developing WT1 peptide-based adoptive T-cell therapy and vaccination against leukemia and solid tumors.

Substance P inhibits pancreatic exocrine secretion via a neural mechanism

We investigated the effects of the sensory neuropeptide substance P (SP) on amylase and fluid secretion in the isolated vascularly perfused rat pancreas. SP inhibited CCK-induced amylase release and secretin-induced juice flow via the pancreatic duct in a dose-related fashion. Threshold inhibition occurred following addition of 10(-10) M SP to the perfusate, and maximal inhibition was seen with 10(-8) M SP. The effects of SP were partially blocked by both the neurokinin-1 (NK1) and neurokinin-2 (NK2) receptor antagonists. Atropine and TTX blocked SP-induced effects on both amylase secretion (26 and 63% blockade, respectively) and pancreatic juice flow (21 and 79% blockade, respectively). Excitation of pancreatic sensory nerves using capsaicin (in the absence of SP) inhibited both amylase and pancreatic juice flow via activation of the NK1 receptor. We conclude that SP inhibits exocrine secretion via an indirect neural mechanism.

Once-daily gentamicin dosing in newborn infants

OBJECTIVE

We developed a simplified gentamicin dosing protocol for all neonates using a loading dose and once-daily dosing that would have an equal or lower incidence of toxicity and an equal or improved effectiveness compared with a regimen with no loading dose that included use of divided daily dosing.

METHODS

All neonatal intensive care unit patients with a postnatal age </=7 days and started on gentamicin therapy at the discretion of the attending neonatologist were evaluated in this comparative cohort study. All peak and trough serum drug levels (SDL), pertinent demographic data, and markers of potential nephrotoxicity, ototoxicity, and cure were tracked prospectively during 132 consecutive, nonrandomized courses of therapy on a new gentamicin protocol. These were compared with data retrieved retrospectively throughout 103 consecutive, nonrandomized courses of therapy in a control group.

RESULTS

Initial measured peak SDL were higher (7.8 +/- 1.1 microgram/mL vs 6.1 +/- 1.0 microgram/mL) and trough SDL were lower (0.9 +/- 0.2 microgram/mL vs 2.7 +/- 0.6 microgram/mL) in the protocol term subset, compared with the control term subset (gestational age, >/=37 weeks; weight, >/=2500 g). One hundred percent of the initial and maintenance peak SDL in term protocol neonates were 5 to 12 micrograms/mL; compared with 84% of the initial and 61% of maintenance peak SDL in the term control group. One hundred percent of the initial and maintenance trough SDL were in the desired range of <2 micrograms/mL in term protocol neonates; compared with 70% of the initial and 94% of maintenance trough SDL in the term control group. No significant differences were found in any SDL in low birth weight neonates (gestational age <37 weeks or weight <2500 g and >1500 g) in the protocol compared with the control group. The very low birth weight (weight <1500 g) protocol neonates had a significantly higher mean initial trough SDL (2.3 +/- 0.7 micrograms/mL vs 1.5 +/- 0.6 micrograms/mL) and a lower incidence of initial trough SDL <2.0 micrograms/mL (30% vs 95%) than very low birth weight neonates in the control group. No differences were seen between groups in incidence of significant rise in serum creatinine or failure of hearing screen.

CONCLUSION

A loading dose followed by once-daily dosing was shown to result in SDL in the safe and therapeutic range in all term neonates in this study. In low birth weight neonates, this regimen resulted in peak and trough SDL throughout therapy that were similar to those observed in the control group. Delaying the initiation of maintenance once-daily dosing until 36 to 48 hours after the loading dose would be expected to result in a higher incidence of initial trough SDL in target range for very low birth weight neonates.

Successful treatment of relapsed T-cell non-Hodgkin's lymphoma with allogeneic peripheral blood stem cell transplantation with double conditioning

We report a patient with T-cell non-Hodgkin's lymphoma (NHL) who relapsed after treatment with relatively intensive third-generation chemotherapy, VACOP-B, and who was safely and effectively treated with allogeneic peripheral blood stem cell transplantation (allo PBSCT) with double conditioning. The first conditioning consisted of carboplatin and etoposide. Twenty-one days later, the second conditioning was performed with cytosine arabinoside, cyclophosphamide, and total body irradiation (AraC/Cy/TBI). Between the periods of the first and second conditioning, autologous (auto) PBSCT (4.4 x 10(5) colony-forming units granulocyte/macrophage (CFU-GM)/kg, 3.8 x 10(6) CD34+ cells/kg) was performed to rescue marrow aplasia after the first conditioning. After the second conditioning, allo PBSCT (2.1 x 10(5) CFU-GM/kg, 8.2 x 10(6) CD34+ cells/kg) was performed from a human leukocyte antigen-identical sibling. Marrow reconstitution after allo PBSCT was rapid. Grade I acute graft-vs.-host disease (GVHD) involving skin and chronic GVHD on the eye was observed. No severe transplantation-related complications occurred. With a follow-up of 22 months after allogeneic PBSCT, the patient is alive without evidence of the disease. This case shows that allo PBSCT with intensive double conditioning may become a new treatment strategy to achieve long-term disease-free survival for young NHL patients of resistant relapse with a great deal of tumor burden and invasion of lymphoma cells in bone marrow.

Constitutive expression of the Wilms' tumor gene WT1 inhibits the differentiation of myeloid progenitor cells but promotes their proliferation in response to granulocyte-colony stimulating factor (G-CSF)

Bone marrow (BM) cells that were concentrated for hematopoietic progenitor cells by in vivo treatment with 5-FU were infected with a recombinant retrovirus containing a human full-sized, non-spliced type WT1 (Wilms' tumor gene 1) cDNA and then colony-assayed in the presence of granulocyte-colony stimulating factor (G-CSF). Significantly more colony-forming units granulocyte-monocyte (CFU-GM), colony-forming units granulocyte (CFU-G), and colony-forming units monocyte (CFU-M) colonies were formed in response to G-CSF from the BM cells infected with the WT1-containing retrovirus than from the control BM cells infected with an empty vector. Furthermore, FACS analysis of cell surface differentiation markers showed the inhibition of differentiation by constitutive WT1 expression resulting from the infection with the WT1-containing retrovirus. These results thus showed that the constitutive WT1 expression promoted the proliferation of myeloid progenitor cells but inhibited their differentiation in response to G-CSF, suggesting the alteration of G-CSF signaling pathway. The results also supported our hypothesis that the WT1 gene performs an oncogenic rather than a tumor suppressor gene function in hematopoietic progenitor cells, although the WT1 gene potentially performs both functions. This finding implies an important role of the WT1 gene in leukemogenesis.

The Wilms' tumor gene WT1 is a good marker for diagnosis of disease progression of myelodysplastic syndromes

The Wilms' tumor gene, WT1, is a tumor marker for leukemic blast cells. The WT1 expression levels were examined for 57 patients with myelodysplastic syndromes (MDS) (refractory anemia (RA), 35; RA with excess of blasts (RAEB) 14; RAEB in transformation (RAEB-t), six; and MDS with fibrosis, two) and 12 patients with acute myeloid leukemia (AML) evolved from MDS. These levels significantly increased in proportion to the disease progression of MDS from RA to overt AML via RAEB and RAEB-t in both bone marrow (BM) and peripheral blood (PB). WT1 expression levels in PB significantly correlated with the evolution of RAEB or RAEB-t to overt AML within 6 months. Therefore, WT1 expression levels in PB were superior to those in BM for early prediction of the evolution to AML by means of quantitation of the WT1 expression levels. Furthermore, WT1 expression in PB of patients with overt AML evolved from MDS was significantly decreased by effective chemotherapy or allogeneic stem cell transplantation and became undetectable in long-term survivors. These results clearly showed that WT1 expression levels are a tumor marker for preleukemic or leukemic blast cells of MDS and thus reflect the disease progression of MDS. Therefore, monitoring of WT1 expression levels has made continuous assessment of the disease progression of MDS possible, as well as the prediction of the evolution of RAEB or RAEB-t to overt AML within 6 months. The results also showed that quantitation of WT1 expression levels is useful for diagnosis of minimal residual disease of MDS with high sensitivity, thus making it possible to evaluate the efficacy of treatment for MDS.

Expression of the Wilms' tumor gene WT1 in solid tumors and its involvement in tumor cell growth

To determine the role of the Wilms' tumor gene WT1 in tumorigenesis of solid tumors, expression of the WT1 gene was examined in 34 solid tumor cell lines (four gastric cancer cell lines, five colon cancer cell lines, 15 lung cancer cell lines, four breast cancer cell lines, one germ cell tumor cell line, two ovarian cancer cell lines, one uterine cancer cell line, one thyroid cancer cell line, and one hepatocellular carcinoma cell line) by means of quantitative reverse transcriptase-polymerase chain reaction. WT1 gene expression was detected in three of the four gastric cancer cell lines, all of the five colon cancer cell lines, 12 of the 15 lung cancer cell lines, two of the four breast cancer cell lines, the germ cell tumor cell line, the two ovarian cancer cell lines, the uterine cancer cell line, the thyroid cancer cell line, and the hepatocellular carcinoma cell line. Therefore, of the 34 solid tumor cell lines examined, 28 (82%) expressed WT1. Three cell lines expressing WT1 (gastric cancer cell line AZ-521, lung cancer cell line OS3, and ovarian cancer cell line TYK-nu) were further analyzed for mutations and/or deletions in the WT1 gene by means of single-strand conformation polymorphism analysis. However, no mutations or deletions were detected in the region of the WT1 gene ranging from the 3' end of exon 1 to exon 10 (the WT1 gene consists of 10 exons) in these three cell lines. Furthermore, when AZ-521, OS3, and TYK-nu cells were treated with WT1 antisense oligomers, the growth of these cells was significantly inhibited in association with a reduction in WT1 protein levels. Furthermore, constitute expression of the transfected WT1 gene in cancer cells inhibited the antisense effect of WT1 antisense oligomer on cell growth. These results indicated that the WT1 gene plays an essential role in the growth of solid tumors and performs an oncogenic rather than a tumor-suppressor gene function.

Wilms' tumor gene (WT1) competes with differentiation-inducing signal in hematopoietic progenitor cells

The WT1 gene is a tumor-suppressor gene that was isolated as a gene responsible for Wilms' tumor, a childhood kidney neoplasm. We have previously reported that the WT1 gene is strongly expressed in leukemia cells with an increase in its expression levels at relapse and an inverse correlation between its expression levels and prognosis, thus making it a novel tumor marker for leukemic blast cells. Furthermore, WT1 antisense oligomers have been found to inhibit the growth of leukemic cells. These results strongly suggested the involvement of the WT1 gene in human leukemogenesis. The present study was performed to prove our hypothesis that the WT1 gene plays a key role in leukemogenesis and performs an oncogenic function in hematopoietic progenitor cells, rather than a tumor-suppressor gene function. 32D cl3, an interleukin-3-dependent myeloid progenitor cell line, differentiates into mature neutrophils in response to granulocyte colony-stimulating factor (G-CSF). However, when transfected wild-type WT1 gene was constitutively expressed in 32D cl3, the cells stopped differentiating and continued to proliferate in response to G-CSF. As for signal transduction mediated by G-CSF receptor (G-CSFR), Stat3alpha was constitutively activated in wild-type WT1-infected 32D cl3 in response to G-CSF, whereas, in WT1-uninfected 32D cl3, activation of Stat3alpha was only transient. However, most interesting was the fact that G-CSF stimulation resulted in constitutive activation of Stat3beta only in wild-type WT1-infected 32D cl3, but not in WT1-uninfected 32D cl3. Thus, WT1 expression constitutively activated both Stat3alpha and Stat3beta. A transient activation of Stat1 was detected in both wild-type WT1-infected and uninfected 32D cl3 after G-CSF stimulation, but no difference in its activation was found. No activation of MAP kinase was detected in both wild-type WT1-infected and uninfected 32D cl3 after G-CSF stimulation. These results demonstrated that WT1 expression competed with the differentiation-inducing signal mediated by G-CSFR and constitutively activated Stat3, resulting in the blocking of differentiation and subsequent proliferation. Therefore, the data presented here support our hypothesis that the WT1 gene plays an essential role in leukemogenesis and performs an oncogenic function in hematopoietic progenitor cells and represent the first demonstration of an important role of the WT1 gene in signal transduction in hematopoietic progenitor cells.

Radionuclide therapy of skin cancers and Bowen's disease using a specially designed skin patch

Skin cancer is the most common malignancy in humans. Therapeutic modalities for skin cancer are local destruction, radiotherapy and surgery. External radiation therapy leads to good results, however, generally 5-6 wk of treatment is needed to deliver optimal radiation dose to tumors. In this study, a beta-emitting radionuclide, 166Ho, impregnated in a specially designed patch, was used on superficial skin cancers and Bowen's disease for local irradiation.

METHODS

Ten mice with chemically induced skin tumors were studied. Five-millimeter size patches containing 22.2-72.15 MBq (0.6-1.95 mCi) 166Ho were applied to the tumor surface for 1-2 hr. In a human trial, patients with squamous-cell carcinoma (n = 3), basal cell carcinoma (n = 1) and Bowen's disease (n = 1) were treated with patches containing 273.8-999 MBq (7.4-27 mCi) of 166Ho for 30 min to 1 hr. Pathologic examination was performed 4-7 wk after treatment in an animal model. Skin biopsy was performed 8 wk post-treatment in four patients.

RESULTS

Tumor destruction was seen 1 wk post-treatment, however, radiation dermatitis or ulceration developed at the site of radionuclide application. Those reactions healed gradually with fibrosis or epithelialization, which was confirmed pathologically. No significant adverse reaction to radiation except subcutaneous fibrosis was found.

CONCLUSION

Superficial skin tumors could be successfully treated by topical application of beta-emitting radionuclides.

Sulfonamide resistance gene in a transferable R plasmid of Pasteurella piscicida

The sulfonamide resistance (SAr) determinant was cloned from a transferable R plasmid of Pasteurella piscicida, pSP9351, and the sequence was determined. The resistance gene (pp-sul) was localized to an approximately 1-kb region that includes the PstI-EcoRI site in the restriction map. An open reading frame coding a sul II-type gene composed of 810 nucleotides was identified. A direct repeat sequence was shown in the 5' flanking region of pp-sul, and a plasmid recombinational event may have occurred during the construction of pSP9351. In the 3' flanking region of the gene, a sequence homologous to the 5' noncoding sequence of the trimethoprim resistance gene, dhfr IX was found.

Retrospective analysis of risks associated with an umbilical artery catheter system for continuous monitoring of arterial oxygen tension

We reviewed retrospectively the incidence of complications encountered with two different umbilical artery catheters (UACs): a silicone-rubber end-hole catheter and an electrode-tipped, side-hole catheter for continuous, invasive monitoring of arterial oxygen tension (PaO2). During calendar year 1989, there were 457 admissions to the neonatal intensive care unit: 168 patients had placement of a UAC. Two of these were admitted only briefly for cardiac catheterization and were eliminated from analysis. One patient had both types of catheters placed sequentially. Thus the data on 166 patients with 51 PaO2 monitors and 116 silicone-rubber UACs were evaluated. The patients who had a PaO2 monitor UAC had a lower mean birth weight than those in the other group (1621 +/- 1043 gm vs 1972 +/- 1048 gm; p = 0.0473). The catheter life span was not different between the groups, with a range of 1 to 16 days for PaO2 monitors and 1 to 27 days for silicone-rubber UACs. Inability to withdraw blood, poor blood pressure tracing, or both conditions resulted in catheter removal for 5 of 51 PaO2 monitor UACs and 4 of 116 end-hole UACs. The incidence of these problems did not differ significantly between the two groups. There were no cases of thromboembolic complications in the patients who had a PaO2 monitor UAC, whereas two of the silicone-rubber UACs were removed because of perfusion problems in the lower limbs, which resolved with decannulation. We conclude that the use of the PaO2 monitor UAC allows for continuous, invasive monitoring of PaO2 without any significant increase in risk compared with that for the silicone-rubber end-hole UAC.

Ras amplification in BHK-21 cells produces a host cell line for further rapid establishment of recombinant protein hyper-producing cell lines

To rapidly establish recombinant protein hyper-producing cell lines we introduced a reporter plasmid into BHK-21 cells that had been 'primed' by transfection and amplification of the ras oncogene. The reporter plasmid used carries the human interleukin-6 (hIL-6) gene which is under control of the human cytomegalovirus immediate early promoter. The primed BHK cell lines were shown to produce many stable hIL-6 hyper-producing cells achieving about 15 times higher productivity than the control BHK-21 cells.

E1A and ras oncogenes synergistically enhance recombinant protein production under control of the cytomegalovirus promoter in BHK-21 cells

The amplified ras oncogene greatly enhanced the production of recombinant human interleukin-6 (hIL-6) under control of the cytomegalovirus immediate early promoter (CMV promoter) in BHK-21 cells. When the adenovirus E1A oncogene was further transfected into the above mentioned ras-amplified hIL-6 hyperproducing BHK cells, the transfectants had about 10 times higher productivity than non-transfectants. However, the E1A gene alone did not enhance productivity. These results implicate a ras and E1A synergistic ability that acts to enhance hIL-6 production.

Experience with double-lumen umbilical venous catheters in the low-birth-weight neonate

Reliable vascular access can be problematic in sick low-birth-weight neonates. Umbilical venous catheters are one form of vascular access that can be used in this population. A retrospective review of experience with umbilical venous catheters in our neonatal intensive care unit from January 1989 through December 1991 was conducted. This included 128 patients: 70 with single-lumen (Gesco Umbilicath II) and 58 with double-lumen (Becton-Dickinson Careflow) catheters. Birth weight, gestational age, catheter life span, complications, and number of punctures for peripheral intravenous lines were analyzed. The mean birth weight, gestational age, and catheter life span did not differ significantly between catheter types. The incidence of catheter-related sepsis did not differ significantly (two single-lumen, three double-lumen) and occurred only in neonates with a catheter life span greater than 10 days. The number of intravenous punctures was significantly decreased in those neonates with double-lumen umbilical venous catheters (p < 0.0001). We conclude that in sick low-birth-weight infants the use of double-lumen umbilical venous catheters entails no greater risk than the use of a single-lumen umbilical venous catheter and may reduce iatrogenic stress associated with the starting of peripheral intravenous lines.

Ras oncogene enhances the production of a recombinant protein regulated by the cytomegalovirus promoter in BHK-21 cells

In order to enhance recombinant protein productivity in animal cells, we developed the oncogene activated production (OAP) system. The OAP system is based on the premise that oncogenes are able to enhance promoter activity. To this end, we constructed reported plasmids by fusing various promoters to the human interleukin-6 (hIL-6) cDNA, and the effector plasmids by inserting individual oncogenes, for example c-myc, c-fos, v-jun, v-myb and c-Ha-ras, downstream from the human cytomegalovirus immediate early (CMV) promoter. Results of transient expression experiments with BHK-21 cells suggest that the CMV promoter is the most potent promoter examined and that the ras product is able to transactivate the beta-actin, CMV and SR alpha promoters. Recombinant BHK-21 cells producing hIL-6 under the control of the CMV promoter were contransfected with the ras oncogene and dihydrofolate reductase gene, then selected with 50 nM methotrexate to coamplify the ras oncogene. We were able to rapidly establish a stable and highly productive clone which exhibited a 35-times higher production rate as compared to the control value.

The transposon-like structure of IS26-tetracycline, and kanamycin resistance determinant derived from transferable R plasmid of fish pathogen, Pasteurella piscicida

Tetracycline (pp-tet), and kanamycin (pp-kan) resistance genes were cloned from a transferable R plasmid of fish pathogen Pasteurella piscicida, and complete nucleotide sequences were determined. The pp-tet was a class D Tet determinant constructed with the tetA resistance gene of 1,182 bp encoding a protein with a deduced molecular mass of 41 kDa and the tetR repressor gene of 654 bp encoding a product of 24 kDa. The pp-tet was highly homologous to the tet(D) of plasmid RA1 isolated from Aeromonas hydrophila with two nucleotide differences in the tetR, and of plasmid pIP173 from Salmonella ordonez with two nucleotide differences in the tetA. The pp-kan contained 813 bp encoding a 31 kDa protein of 271 amino acids, and was classified into type aph-Ic. It was identical to the aphA7 in the IAB operon of pBWH77, in which was originally found an isolate of Klebsiella pneumoniae, in its nucleotide sequences and hybrid promoter construction. The genes were connected by an insertion sequence IS26 of 820 bp, and were flanked by repeated copies in direct orientation at the 3' flanking region of the pp-tetA and in inverted orientation at the 3' flanking region of the pp-kan. The genetic elements are organized like a complex transposon by close linkage of the IS26 and the pp-tet and -kan.