Effect of levofloxacin on glycosaminoglycan and DNA synthesis of cultured rabbit chondrocytes at concentrations inducing cartilage lesions in vivo

We investigated the toxic effect of levofloxacin (LVFX), a quinolone antibacterial agent, on cartilage by examining aspects of its in vivo toxicokinetics and effect on the function of cultured chondrocytes of the femoral articular cartilage from juvenile New Zealand White rabbits. Repeated administration of LVFX (100 mg/kg) orally for 7 days induced focal necrosis and superficial erosion in the articular cartilage of the femoral condyle, but 30 mg/kg did not. Concentrations of LVFX in the cartilage were highest at the first sampling point (30 min) after a single administration, being 4.93 and 12.2 micrograms/g in the 30- and 100-mg/kg groups, respectively. The arthropathic concentration of LVFX in the cartilage was then shown to be 12.2 micrograms/g or more. For an in vitro study, chondrocytes were separated from the articular cartilage of the rabbit femoral condyle and cultured for 7 days until confluence. 35SO4 uptake by cultured chondrocyte sheets was most susceptible to LVFX, decreasing at drug concentrations of 5 micrograms/ml or more in 24- and 48-h cultures but not in a 72-h culture. Furthermore, 3H-thymidine uptake was decreased at concentrations of 10 micrograms/ml or more in a 48-h culture but not in 24- and 72-h cultures. Rhodamine 123 accumulation was susceptible to inhibition in cultured chondrocytes at an LVFX concentration of 10 micrograms/ml or more. These results suggest that LVFX inhibits glycosaminoglycan synthesis initially and DNA synthesis and mitochondrial function secondarily at actual arthropathic concentrations in cultured rabbit chondrocytes but that these changes are reversible and not enough to kill the cells.

Disruption of the function of tumor-suppressor gene p53 by the hepatitis B virus X protein and hepatocarcinogenesis

The X gene of the hepatitis B virus codes for a small basic protein and is able to transactivate viral and cellular genes, although the X protein exhibits no DNA-binding activity. The mechanism of transactivation by X protein has been suggested to be via protein-protein interaction(s). We first demonstrated that X protein had amino acid sequences homologous to the functionally essential domain of Kunitz-type serine protease inhibitors and that those sequences were indispensable for the transactivation function. We demonstrated that X protein exhibited an inhibitor activity against hepatic serine proteases, and subsequently found that the protein activated X gene transcription in HepG2 cells and that the X responsive element was localized in the minimal promoter of the X gene. In contrast, the tumor-suppressor gene p53, but not mutant p53, remarkably reduced transcription from the minimal promoter. This p53 repression on the X gene promoter was cancelled by X gene co-expression, probably indicating that the X protein disrupts the p53 tumor suppressor function in the nucleus. All data suggest that X protein leads to transactivation of cellular oncogenes by preventing an interaction between p53 and cellular transcription factor(s) consisting of the basal transcriptional machinery.

[A case of remission of recurrent carcinosarcoma of the uterus with massive ascites by carboplatin]

A case of remission of recurrent carcinosarcoma of the uterus with massive ascites by chemotherapy using carboplatin (CBDCA) is reported. A 75-year-old female was diagnosed with cancer of the uterine body. She underwent abdominal total hysterectomy with bilateral salpingo-oophorectomy, which revealed carcinosarcoma of the uterus penetrating the myometrium and reaching the serosa of the uterus. Eight weeks after, she developed abdominal distension, obstruction of bilateral ureters and bleeding tumor measuring 5 cm in diameter at the vaginal cuff ending. Acute retention of bloody ascites of more than 2500 ml was demonstrated. Abdominal centesis, aspiration of ascites and intraperitoneal administration of 600 mg of CBDCA were performed. Two weeks after single use of CBDCA, the ascites completely disappeared and there was recovery from anuria. The remission has lasted more than 4 months, which has suggested the efficacy of CBDCA for uterine carcinosarcoma.

Detection of aberrations in androgen receptor gene by analysis of single-stranded conformation polymorphisms in polymerase chain reaction products

Analysis of single-stranded conformation polymorphisms in polymerase chain reaction (PCR) products (PCR-SSCP) is a sensitive method for detecting point mutations in genomic DNA. To investigate its utility in examining the androgen receptor gene, we analyzed data on a patient with the testicular feminization syndrome (TFS) with a known point mutation in exon C. We detected mobility shifts of fragments of the corresponding region. Since examination of the subject's brother (legally sister), who also has TFS, revealed an identical shift pattern, we sequenced the exon C of the sibling and detected a mutation identical to that in the former. We conclude that PCR-SSCP is available for screening mutations of the androgen receptor gene.

Receptor-mediated transfer of pSV2CAT DNA to a human hepatoblastoma cell line HepG2 using asialofetuin-labeled cationic liposomes

Asialofetuin-labeled liposomes (AF-lps) were developed as a vector for gene transfer to hepatocytes. Plasmid pSV2CAT DNA which encodes bacterial chloramphenicol acetyltransferase (CAT) was associated with (meaning, in this report, the sum of 'to be adsorbed on the surface of' and 'to be encapsulated into the internal phase of') AF-lps (AF-lps-pSV2CAT) prepared by a tandem combination of the detergent removal and freeze-thaw methods. Ninety-six percent of input pSV2CAT was associated with AF-lps containing N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, and approx. two-thirds of the associated DNA was encapsulated into the internal phase. The uptake of AF-lps by the cultured human hepatoblastoma cell line HepG2, having asialoglycoprotein receptors (AGPR) on their plasma membrane, was decreased by the addition of free AF and cytochalasin B. AF-lps bound to HepG2 cells through specific interaction with AGPR, and were internalized into the cells by the receptor-mediated endocytotic pathway. HepG2 cells transfected by AF-lps-pSV2CAT showed a significantly higher CAT activity than those transfected by pSV2CAT associated with non-labeled control lps (N-lps-pSV2CAT) or a mixture of pSV2CAT and empty AF-lps. Pretreatment with EDTA-encapsulated AF-lps increased the transfection efficiency of AF-lps-pSV2CAT. The CAT activity in A431 and Swiss/3T3 cells transfected with AF-lps-pSV2CAT was low and almost the same as those transfected with N-lps-pSV2CAT. Since DNA encapsulated in lps is likely to be protected against digestion by nucleases in the blood circulation, AF-lps could be used as a gene transfer vector targeting the hepatocytes in vivo.

[Ischemic cerebrovascular disease in patients with atrial fibrillation]

The purpose of this retrospective study was to elucidate 1) which subgroups are prone to have ischemic cerebrovascular disease (CVD) among patients with atrial fibrillation (Af), 2) vulnerable period of CVD after the diagnosis of chronic Af and 3) the clinical efficacy of antiplatelet therapy in chronic nonvalvular Af patients. During 9 years, a total of 479 patients included 124 cases with paroxysmal Af, 30 cases with paroxysmal Af initially which later changed to chronic Af and 325 cases with chronic Af were enrolled. Among these 355 cases with chronic Af, 57 cases had valvular heart disease (VHD). The results were as follows: 1) The high risk subgroups (incidence rate/100 person-years is more than 6) were chronic Af with VHD or hypertension. The low risk subgroups (less than 2) were paroxysmal Af under 60 years of age, chronic Af with mitral valve prolapse syndrome or with hyperthyroidism. 2) There was no vulnerable period for occurrence of CVD during 9 years' follow-up from the onset of Af. 3) No significant difference in the incidence of CVD was seen in the groups with antiplatelet therapy and without.

Application of a spray drying technique in the production of TRH-containing injectable sustained-release microparticles of biodegradable polymers

Copoly (dl-lactic/glycolic acid) microparticles for sustained release of a water-soluble drug (Thyrotropin releasing hormone: TRH) were prepared by a spray drying method. A higher entrapment ratio was achieved with the spray drying method with the in-water drying method. In order to avoid agglomeration of the microparticles, a double-nozzle spray drying method was designed using mannitol as an anti-adherent. The surface of the spray-dried microparticles was coated with mannitol, and the extent of agglomeration was decreased. Acetonitrile was the most suitable solvent for microencapsulation using the double-nozzle spray drying method because the initial burst of TRH from the microparticles during the first day was the smallest. When PLGA with a weight-average molecular weight of 14,000 was used, constant release of TRH continued for one month with a small initial burst. In conclusion, the production of biodegradable microparticles by the double-nozzle spray drying method appears to be an attractive alternative to conventional microencapsulation methods.

Different effect of cyclosporin A on arthritides induced by a muramyl dipeptide analogue or the complete adjuvant in rats

Muramyl dipeptide-Lys(L18) given by daily subcutaneous injection for 14 days induced arthritis in male Lewis, Fischer and nude rats, to a lesser degree in the last two than in the first strain. On the other hand, a single intradermal administration of Freund's complete adjuvant induced arthritis in Lewis and Fischer but not nude rats. Cyclosporin A (CsA) co-administered for 14 days markedly exacerbated the muramyl dipeptide-Lys(L18) induced arthritis (MIA) in rats of all three strains, but completely blocked the development of the adjuvant induced arthritis (AIA) in Lewis rats. Furthermore, AIA was transferred to recipient Lewis rats through spleen cells obtained from the donors with AIA, whereas MIA was not. Antibodies against type II collagen and DNA were not detected in sera from MIA or AIA rats. These data show a clear difference between MIA and AIA in the pattern of development of arthritis and suggest that delayed hypersensitivity reactions may be involved in the pathogenetic mechanisms of AIA, but not in MIA.

Histological examination on Achilles tendon lesions induced by quinolone antibacterial agents in juvenile rats

We examined the effects of the quinolone antibacterial agents pefloxacin (PFLX) and ofloxacin (OFLX) on the Achilles tendon of Sprague-Dawley rats. A single oral administration of PFLX 300 and 900 mg/kg or OFLX 900 mg/kg induced edema with mononuclear cell infiltration mainly in the inner sheath of the inner Achilles tendon just proximal to the tuber calcanei in rats killed on the next day. Cell infiltration was also seen in the adjacent synovial membrane and joint space. With progression of severity, the lesions extended to the surface tendon tissue, wherein irregularly arranged collagen bundles were detached from each other and nuclei of fibroblasts were pyknotic and fragmented. After 2-wk repeated administration, these lesions were replaced by fibrotic foci with regenerated tendon fibroblasts, and the incidence and severity were reduced in the OFLX but not PFLX groups. Coadministration of cyclosporin A with OFLX 300 mg/kg induced these lesions despite the fact that neither induced lesions alone. The tendon lesions were induced in juvenile rats (4 wk of age) but not in young adults (12 wk). The articular cartilage of juvenile rats showed focal degeneration and/or cavitation in the tarsal joints after a single and 2-wk administration of PFLX or OFLX. Hydrocortisone slightly increased the incidence of OFLX-induced lesions in both the tendon and cartilage after a 2-wk administration. The occurrence of the tendon lesions is different from that of the Achilles tendon disorders reported in older humans, but they are thought to be a useful model for them.

Preventive effects of dexamethasone on hypoxic-ischemic brain damage in the neonatal rat

To clarify the preventive effects of glucocorticoid on perinatal hypoxic-ischemic (HI) brain damage, an experiment was carried out on 4-day-old rats pretreated for 4 consecutive days with 3 different regimens; namely, a low dose dexamethasone (Dex) (0.1 mg/kg/day), a high dose Dex (0.5mg/kg/day), and a saline administration. On the 7th postnatal day, after ligation of the left common carotid artery, the rats were exposed to 8% oxygen and decapitated on the 10th, 14th, 21st and 28th postnatal days. Ligated side brain damage was observed in 75, 7 and 3% of the rats in the saline, low and high dose Dex groups, respectively. However, a high mortality rate (42%) was noted in the high dose Dex group. The cumulative number of animals with poor outcome (death or brain damage) was 49 (80%), 13 (33%) and 24 (44%) in the saline, low and high dose Dex groups, respectively. On the 10th and 14th postnatal days, the rats in both the Dex groups showed delayed neuronal maturation and myelination in the non-ligated side motor cortex, however, these maturational differences disappeared on the 21st postnatal days. Otherwise, the number of cortical cells in both the Dex groups were significantly lower than that in the saline group on the 28th postnatal days (P < 0.05 in each). These findings suggest that the pretreatment with Dex protects the developing brain from HI injury through the suppression of the neuronal maturation. However, a decreased number of cortical cells may give rise to psychomotor retardation later.

[Value of 123I-BMIPP scintigraphy in patients with ischemic heart disease: comparison with exercise 201Tl SPECT]

To evaluate 123I labeled beta-methyl-branched fatty acid (BMIPP) myocardial uptake at rest in the segment with and without stress induced ischemia in patients with coronary artery disease, 123I-beta-methyl-branched fatty acid myocardial scintigraphy was performed at rest and was compared with the findings of stress-reinjection 201Tl myocardial scintigraphy in 31 patients with coronary artery disease. In 159 ischemic myocardial segments, equally decreased uptake on both reinjection 201Tl and fatty acid images was observed in 64 segments, more severely decreased uptake of fatty acid in 76 segments, and more severely decreased uptake of reinjection thallium in 19 segments. On the other hand, in 53 non-reversible defects, each patterns was observed in 41, 3, and 9 segments respectively. When comparing the ischemic segments with more reduced uptake of fatty acid than reinjection thallium (Group 1) and the ischemic segments with equally or less reduced fatty acid uptake than reinjection thallium (Group 2), wall motion was more severely impaired in Group 1 than in Group 2 (severe hypo- to dyskinesis was present in 32 of 54 segments in group 1 and in 21 of 75 segments in group 2, p < 0.005). In conclusion, in patients with coronary artery disease, resting fatty acid uptake was frequently more reduced than reinjection 201Tl in the segments with stress induced ischemia and wall motion was more impaired in these segments. BMIPP myocardial imaging may provide information on metabolic alterations at rest independent of perfusion abnormalities in patients with coronary artery disease.

A direct role of transcription factor E2F in c-myc gene expression during granulocytic and macrophage-like differentiation of HL60 cells

The transcription factor E2F is known to play an important role in cell cycle progression through interaction with retinoblastoma protein. HL60 cells are able to differentiate into a granulocytic lineage by prolonged exposure to retinoids and into a macrophage-like lineage by exposure to tumor promoter 12-O-tetradecanoylphorbol 13-acetate, with a rapid decrease of c-myc gene expression. In this study, we assessed the changes of the E2F-binding pattern to the P2 promoter region of the c-myc gene during differentiation into both lineages. The observed changes of the E2F-binding pattern were a decrease of free E2F and an appearance of retinoblastoma protein-containing E2F complexes in both lineages. The effects of the anti-c-myc antibody and the recombinant c-Myc protein on the E2F-binding patterns suggest that the c-Myc protein is not involved directly in these changes. These changes also led the suppression of transcriptional initiation from the P2 promoter. The results indicate that, in the course of HL60 cell differentiation, E2F plays a direct role in the transcriptional control of the c-myc gene through interaction with the retinoblastoma protein. A potential role for the c-Myc protein is discussed in relation to an existing state of E2F and E2F-RB complexes in the HL60 cells.

Biochemistry and functions of hepatitis B virus X protein

Hepatitis B virus X gene codes for a small basic cytoplasmic protein and is able to transactivate viral and cellular genes, although X protein exhibits no DNA-binding activity. The mechanism of transactivation by X protein has been suggested to be via protein-protein interaction(s). X protein had amino acid sequences homologous to the functionally essential domain of Kunitz-type serine protease inhibitors, and these sequences were indispensable for transactivation function. X protein activated X-gene transcription itself and an X-responsive element were localized in their minimal promoter. Furthermore, tumor suppressor gene product p53, but not mutant p53, repressed X-gene transcription from the minimal promoter, indicating that X protein disrupts the function of normal p53, which represses transcription of X gene or cellular gene. Data suggest that inhibition of a hepatic serine protease by X protein leads to eliminate the suppressor effect of p53 on the basic transcription machinery in nucleus.

Effects of maternal administration of dexamethasone and thyrotropin-releasing hormone on fetal rat pulmonary surfactant synthesis

To determine the effects of maternal administration of dexamethasone (DEX) and thyrotropin-releasing hormone (TRH) on fetal lung maturation, 16 pregnant rats were divided into the following four groups: 20 micrograms/kg TRH twice a day was given intraperitoneally to the TRH group rats, 0.5 mg/kg/day DEX to the DEX group and both DEX and TRH to the DEX + TRH group for 3 consecutive days from gestational day 17. The control rats were given an equivalent volume of saline. The pregnant rats were sacrificed on gestational day 20 and the fetal lungs were removed. The relative amounts of surfactant protein A (SP-A), B (SP-B) and C (SP-C) mRNAs were analyzed by Northern blotting and the total lung disaturated phosphatidylcholine (DSPC) contents were determined using an enzymatic method. The SP-B and -C mRNA and DSPC contents in the DEX and DEX + TRH groups were significantly higher than those in the control group, whereas the SP-A mRNA levels did not differ significantly among the four groups. The SP-B and -C mRNA and DSPC contents in the DEX and DEX + TRH groups did not differ significantly. These findings suggest that TRH has no effects on the regulation of surfactant protein mRNAs or DSPC contents in the fetal rat lung and has no additive effects when combined with DEX.

Effects of alcohol ingestion on vestibular function in postural control

In order to define the acute effects of a moderate quantity of alcohol on balance, related to the vestibular function, vestibulo-ocular reflex (VOR) test, caloric test and dynamic posturography (EquiTest) were performed. Ten healthy male volunteers aged 19-27 average 22.8) years old imbibed 1.5 ml whisky (alcohol content 43%) per kilogram of body weight within 5 min. Blood alcohol level (BAL) was measured before administration and then after 30, 90, and 150 min. Equilibrium examinations were performed immediately after each blood sample was taken. At the highest alcohol level, significant reductions were found in VOR gain, in the maximum slow-phase velocity of the caloric test and in the equilibrium score of the sensory organization test in condition 5, when compared with those before drinking. In some typical cases, the subjects' response in all tests were most disturbed at the time when the highest alcohol level was measured. From our results, we conclude that a moderate quantity of alcohol affects not only the oculomotor system but also the vestibular system. Furthermore, it was suggested that one of the reasons for postural instability after drinking alcohol may be reduced vestibular function.

Three sites of the hepatitis B virus X protein cooperatively interact with cellular proteins

The X protein of hepatitis B virus is known to be a trans-activator of viral and cellular genes and to be a serine protease inhibitor as well. X protein has no DNA-binding activity, but is postulated to exert its trans-activation function by interacting with cellular proteins. To investigate interaction sites of X protein with cellular proteins, we carried out an immunoprecipitation inhibition assay using several different anti-X antibodies in the presence or absence of cellular proteins. Results elucidated three separate sites (aa 65-72, aa 105-115, and aa 131-142; U22, X1, and Z44 sites, respectively) of the X protein that cooperatively interacted with cellular proteins. Analyses with a series of mutant X proteins also supported the interactions at the U22, X1, and Z44 sites. Based on the CAT activity assay, the essential regions for the trans-activation function of X protein overlapped with these three interaction sites. Furthermore, these interaction sites also coincide with the structures necessary for the serine protease inhibitor activity. Thus, the trans-activation function and serine protease inhibitor activity of X protein may be exerted by interaction with cellular proteins through at least these three sites.

Role of nuclear histone-H1 kinase in regeneration of rat liver

The activities of nuclear histone-H1 kinase and C-kinase as well as the amount of phosphate bound to histone-H1 following partial hepatectomy were studied in rat. It was found that the nuclear histone-H1 kinase activity increased twice within 80 h, first 20 to 30 h, and second at 50 to 70 h after partial hepatectomy. The timing of increase of the enzyme activity correlated with increased amount of bound phosphate. On the other hand, the increase of the C-kinase activities occurred between 5 and 15 h after partial hepatectomy. Antibodies raised against human cdk2, human cyclin-A and mouse cdc2 kinase showed no detectable effect on the nuclear histone H1 kinase activity. These results suggest that phosphorylation of histone-H1 in liver regeneration may be catalysed by a putative kinase(s).

Experimental control of axial pattern in the chick blastoderm by local expression of Wnt and activin: the role of HNK-1 positive cells

Small grafts from transfected mammalian cell lines that secrete activin or express Wnt-1 RNA were made to the marginal zone of entire chick blastoderms in culture. Grafts from appropriate control cell lines produced no effects on development. The activin-secreting grafts, implanted before streak formation, could cause the streak to form opposite their marginal position even when this was 180 degrees distant around the blastoderm from the original presumptive streak site. Alternatively, opposed twin streaks were observed, one at the original presumptive site and one in relation to the graft. Wnt-expressing grafts implanted early could also reposition axis formation, but only to graft sites within approximately 100 degrees of angular distance from the host's presumptive streak origin. No Wnt-induced twinning was observed. Grafts of both experimental cell types intermixed were the most effective in reorientating, twinning, or globally disturbing the axial pattern and led to second axes with the least delay, relative to normal development, in reaching headfold stages. The incidence and distribution of cells positive for the epitope HNK-1 was investigated during early stages of normal and of experimentally twinned development. Only two nonhypoblast regions of HNK-1 expression were consistently observed in normal early development; a sector in the germ wall area opaca, behind the site of streak formation, and then a localised region of intensely, newly expressing cells arising in epiblast and in anteriormost parts of the (epiblast-derived) streak at the half-length streak stage. Both "activin only" and "activin/Wnt" mixed grafts, although not control grafts, became surrounded by new sectors of "germ wall" HNK-1 positivity. Such positivity may therefore mark a cell group with a signaling role (but no anatomical participation) in streak initiation. However, there was no change of the local background incidence of epiblastic HNK-1 positivity in the structure of streaks induced by "activin only" grafts. This indicates that most cells of the streak are specified by relatively local induction, rather than deriving from selective aggregation. Only grafts including the Wnt-expressing cells gave rise to obvious new HNK-1 expression within epiblast-derived cells anteriorly, as does the complete normal streak. This suggests that the Wnt class of response pathway can complement the activin one in producing rostrocaudally complete axial pattern, as has been suggested for amphibian development.

Occupational exposure to solvent mixtures: effects on health and metabolism

Exposure monitoring by personal diffusive samplers, biological monitoring of toluene exposure by urinary hippuric acid determination, haematology, serum biochemistry for liver function, and a subjective symptom survey by questionnaire were conducted on 303 male solvent workers. They were exposed to a mixture of solvents including toluene (geometric mean 18 ppm), methyl ethyl ketone (MEK; 16 ppm), isopropyl alcohol (IPA; 7 ppm), and ethyl acetate (9 ppm). The intensity was mostly below unity using the additiveness formula based on current Japanese occupational exposure limits, but more than eight times unity at the maximum. The results were compared with the findings in 135 non-exposed male workers of similar ages. Haematology and liver function tests did not show any exposure related abnormality, and subjective symptoms were mostly related to central nervous system depression and local irritation. Further analysis suggested that the irritation effects were not related to exposure to MEK. Analysis of the relation between toluene exposure and hippuric acid excretion in urine showed that there was no metabolic interaction between MEK and toluene, or between IPA and toluene. Overall, therefore, it is concluded that there was no sign or symptom detected to suggest anything other than toluene toxicity, that there was no evidence to indicate any modification of toluene toxicity or metabolism due to coexposure, and that the additiveness assumption is reasonable for risk assessment for the combination of solvents under these exposure conditions.