Local substances regulating cochlear blood flow

The regulation of cochlear lateral wall blood flow was investigated in rats using histochemistry, immunohistochemistry and transmission electron microscopy. The contractile protein, tropomyosin (TM) was localized in the pericyte around the vessels of spiral ligament but little was seen around strial capillaries. Prostaglandin I2 (PGI2) is a vasodilatory substance produced by PGI2 synthase (PGI2S), which is present in the endothelium of the vessels of spiral ligament but not much is present around strial capillaries. Endothelial nitric oxide synthase (eNOS) was present in the endothelium of both the vessels of spiral ligament and strial capillaries. These findings indicate that the blood flow of the cochlear lateral wall is regulated mainly in the spiral ligament by locally produced substances and that strial blood flow is not significantly regulated by pericytes responsible for enlargement or constriction of capillaries.

Evaluation of the vertebrobasilar artery system by magnetic resonance angiography in the diagnosis of vertebrobasilar insufficiency

To evaluate the advantages of magnetic resonance angiography (MRA) in assessing the vertebrobasilar artery system for diagnosing vertebrobasilar insufficiency (VBI), we compared the MRA results of middle-aged and older VBI cases with those of age-matched peripheral disorder cases. There were no significant differences in the rate of complications associated with atherosclerosis between VBI cases and peripheral disorder cases. The MRA results were quantitatively assessed by scores determined on the basis of the severity of stenosis in the vertebral arteries and basilar artery. The MRA score was defined as the total score of these three arteries. The severity of stenosis and the MRA score of VBI cases were significantly higher than those of peripheral cases. MRA can therefore be of value as a screening examination for estimating vertebrobasilar blood flow and can provide helpful information for diagnosing VBI.

Cycloheximide blocks the toxic effect of streptomycin in guinea pig vestibular hair cells

Apoptosis has been suggested to be a predominant cell death process for streptomycin-induced degeneration of vestibular hair cells. However, the biochemical aspects of this have not been studied. The purpose of this study was to examine the biochemical aspects of apoptosis of vestibular hair cells caused by streptomycin. Cycloheximide is a widely used protein synthesis inhibitor in studies of apoptosis. We therefore investigated cycloheximide effects on degeneration of vestibular hair cells following streptomycin applications. Supplements of cycloheximide significantly prevented DNA fragmentation in hair cell nuclei and reduced the loss of hair cells. This suggests that cycloheximide possibly inhibits apoptosis of hair cells and attenuates streptomycin-induced degeneration of the vestibular epithelium.

Study of tuberculosis in the field of otorhinolaryngology in the past 10 years

Over the 10 years from 1988 to 1997, a total of 18 cases of tuberculosis of the head and neck (8 of the cervical lymph node, 5 of the larynx, 2 of the salivary glands, and 1 each of the hypopharynx, tongue and middle ear) were diagnosed in our department. Four cases were diagnosed in 1996 and 8 in 1997, indicating a rapid increase over these 2 years. Definitive diagnosis was based on histopathological examination in 14 cases, detection of M. tuberculosis in 1 case and exclusion diagnosis, mainly using the tuberculin skin test, in 3 cases. The length of time from the first examination to obtaining a definitive diagnosis was 14.2 +/- 6.5 days in five subjects in whom tuberculosis was suspected from the beginning or in whom tuberculosis was suggested by the physician in making a differential diagnosis, 25.3 +/- 17.2 days in the group in whom malignant tumour was suspected and 64.3 +/- 57.3 days in other cases. Although no significant difference was found (p = 0.077), the length of time until diagnosis tended to be shorter in the cases that were suspected of having tuberculosis from the beginning. Family history and past history of tuberculosis, contact with a tuberculous patient and abnormal findings at chest X-ray were examined as background factors, and some of these were present in nine out of the 18 cases. In the five cases diagnosed in the early stage, some of the background factors were found in four cases. However, no significant difference in the time until definitive diagnosis was found between the groups with or without background factors in all cases (p = 0.675). These results suggest the importance of considering tuberculosis when performing differential diagnoses.

Comparative assessment of cell proliferation and accumulation of extracellular matrix in nasal polyps

In nasal polyps constantly associated with chronic inflammation, a dysregulation of epithelial cell proliferation has been described. Involvement of extracellular matrix accumulation is also suggested in the formation and growth of nasal polyps. In this study, we attempted to evaluate the activity of the proliferation of epithelial cells and fibroblasts and the relation between fibronectin accumulation and these cell proliferations in nasal polyps. The pathological specimens of 30 patients were examined which manifested proliferating cell nuclear antigen (PCNA) expression in epithelial cells and fibroblasts and in fibronectin expression. PCNA expression was quantified by calculating the index for each sample. No significant difference in PCNA index was found between epithelial cells and fibroblasts. However, a significant correlation was found between the epithelial and fibroblastic PCNA index. In addition, fibronectin immunopositivity was well correlated with the activity of proliferation of fibroblasts. Therefore, proliferation of fibroblasts is also an important factor in the growth of nasal polyps, and its relationship with fibronectin accumulation may play a role in the pathogenesis of nasal polyposis.

Role of amino acids in cochlear degeneration: deprivation of cystine induces death of cochlear hair cells of guinea pigs in vitro

Redox regulation reportedly plays a role in maintaining cochlear homeostasis. However, little is known about the roles of oxidation-reduction systems in the cochlea. We examined the role of the cystine/cysteine oxidation-reduction system in survival of cochlea hair cells in vitro. The survival of hair cells was evaluated in cochlea specimens following incubation with the medium supplemented with various concentrations of cystine. Dying hair cells were detected by the trypan blue extrusion method. The rates of cell death for both outer and inner hair cells increased significantly with a decrease in the concentration of cystine. In addition, the rate of cell death of IHCs tended to be higher than that of OHCs. These findings suggest that the cystine/cysteine system might be required for maintenance of homeostasis in cochlear hair cells, especially in IHCs.

Role of amino acids in cochlear degeneration: morphological changes in cochlear outer hair cells following glutamate application

Glutamate is an excitatory neurotransmitter in the cochlea and has toxic effects on the organ of Corti in various pathological conditions. The toxic effects of glutamate have not been determined in detail. In this study, we examined morphological changes in the organ of Corti of guinea pigs following local application of glutamate. Morphological changes were noted in outer hair cells. Degeneration of outer hair cells was found 24 h after glutamate treatment. The extent of degeneration depended on exposure time. Inner hair cells did not exhibit any degeneration. In addition, no degenerative changes were detected in nerve endings attached to hair cells. These findings suggest that outer hair cells are the initial site of degeneration caused by application of excess glutamate to the inner ear.

Surgical treatment of cancer extending from the retromolar fossa to the masticator space

Cancer extending from the retromolar fossa to the masticator space with neck metastasis (T4N2M0, Stage IV) was surgically removed en bloc by maxillectomy using a mandibular swing technique. This approach allowed a wide surgical view and was useful as handling the external and internal pterygoid muscles and upper neck dissection could be combined. Though there have been several surgical approaches to the masticator space, in the case of tumors which are commonly malignant there, this approach is useful and satisfactory.

Cleavage product from the NO donor NOC-5 and inner ear hair cell damage

Nitric oxide (NO) is a neurotoxic gas which causes neuronal cell death. NO ototoxicity has also been reported, 1-Hydroxy-2-oxo-3-(3-aminopropyl)-3-isopropyl-1-triazene (NOC-5), NO donor, was used for studying NO. In this in vitro study, we examined whether NOC-5 and the cleavage products arising from it after production of No have ototoxic effects on the cochlea. The temporal bones of 55 guinea pigs were dissected and incubated in Dulbecco Modified Eagle's Medium (DMEM) with low glucose and 10% foetal bovine serum (FBS) perfused with various concentrations (100, 50, 10, 1 mM, 100 microM) of NOC-5 (pH 7.4) or the same concentrations of N-isopropyl 1-3 propanildiamine (R-NH2). Hair cell death was assessed using trypan blue staining. With NOC-5, percentages of outer hair cell death were 99.2, 98.0, 45.2, 40.5, and 20%, respectively, and percentages of inner hair cell death were 69.3, 70.2, 22.5. 11.1 and 0%, respectively. With R-NH2, percentages of outer hair cell death were 90.3, 81.1, 29.8, 21.0 and 19.3%, respectively, and percentages of inner hair cell death were 61.4, 48.1, 10.2, 5.4 and 0%, respectively. Ultramicroscopic examination showed that hair cell death was necrotic. Although NOC-5 is useful for study of NO, its cleavage products are also ototoxic.

High-dose ifosfamide, carboplatin and etoposide with autologous peripheral blood progenitor cell transplantation for small-cell lung cancer

BACKGROUND

We investigated the feasibility and efficacy of high-dose chemotherapy consisting of ifosfamide, carboplatin and etoposide (HD-ICE) facilitated by autologous peripheral blood progenitor cell transplantation (ABPCT) for the treatment of small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Eleven patients aged 44 to 63 years old (5 with extensive disease [ED] and 6 with limited disease [LD]) were entered into this study. Induction chemotherapy consisted of 3 to 4 cycles of cisplatin and irinotecan for ED-SCLC, and cisplatin and etoposide for LD-SCLC. Patients with LD-SCLC received concurrent chest radiotherapy along with the first cycle of induction chemotherapy. After induction therapy, peripheral blood progenitor cells (PBPC) were collected following G-CSF administration during a recovery phase from high-dose etoposide (1,500 mg/m2). Eight patients (4 with ED and 4 with LD) with adequate organ function were treated with HD-ICE (15 g/m2 ifosfamide, 1,200 mg/m2 carboplatin and 1,500 mg/m2 etoposide) followed by ABPCT.

RESULTS

Hematologic recovery was rapid and non-hematological toxicities were acceptable without treatment-related mortality. In ED-SCLC, all of the 4 patients achieved complete response (CR) or near CR but developed a relapse of the disease. In LD-SCLC, 2 of 4 patients with LD-SCLC are alive in continuous CR for 18 and 21 months after the beginning of induction therapy.

CONCLUSIONS

Despite a limited number of patients and short follow-up time, these preliminary results indicate that marrow-ablative therapy (HD-ICE) supported by ABPCT is feasible in the treatment of elderly patients with LD- and ED-SCLC.

Purification and activation of recombinant p38 isoforms alpha, beta, gamma, and delta

p38 is a proline-directed serine/threonine kinase that is activated by inflammatory cytokines and cellular stress. At present, four isoforms of p38 have been identified and termed alpha, beta, gamma, and delta. We expressed each p38 homolog in Escherichia coli and purified the recombinant isoforms. p38alpha and C-terminal Flag-tagged p38beta were purified by Q-Sepharose fast flow, hydroxyapatite, and Q-Sepharose high-performance chromatography. His-tagged p38gamma was purified using Ni2+-NTA resin followed by Mono Q chromatography. Glutathione S-transferase-Flag p38delta was purified using M2 affinity agarose and gel-filtration chromatography. Upstream activators of p38, constitutively active (ca) MKK3 and MKK6, were also cloned, purified, and used to activate each p38 isoform. p38 alpha, gamma, and delta were phosphorylated by both MKK6 and caMKK3. p38beta was phosphorylated only by MKK6. Mass spectrometry analysis and kinase assays showed that MKK6 was the superior reagent for phosphorylating and activating all p38 isoforms.

Cloning and characterization of cDNAs encoding S-RNases from almond (Prunus dulcis): primary structural features and sequence diversity of the S-RNases in Rosaceae

cDNAs encoding three S-RNases of almond (Prunus dulcis), which belongs to the family Rosaceae, were cloned and sequenced. The comparison of amino acid sequences between the S-RNases of almond and those of other rosaceous species showed that the amino acid sequences of the rosaceous S-RNases are highly divergent, and intra-subfamilial similarities are higher than inter-subfamilial similarities. Twelve amino acid sequences of the rosaceous S-RNases were aligned to characterize their primary structural features. In spite of their high level of diversification, the rosaceous S-RNases were found to have five conserved regions, C1, C2, C3, C5, and RC4 which is Rosaceae-specific conserved region. Many variable sites fall into one region, named RHV. RHV is located at a similar position to that of the hypervariable region a (HVa) of the solanaceous S-RNases, and is assumed to be involved in recognizing S-specificity of pollen. On the other hand, the region corresponding to another solanaceous hypervariable region (HVb) was not variable in the rosaceous S-RNases. In the phylogenetic tree of the T2/S type RNase, the rosaceous S-RNase fall into two subfamily-specific groups (Amygdaloideae and Maloideae). The results of sequence comparisons and phylogenetic analysis imply that the present S-RNases of Rosaceae have diverged again relatively recently, after the divergence of subfamilies.

Characterization of a protein kinase gene responsive to auxin and gibberellin in cucumber hypocotyls

By means of the PCR, cDNA clones encoding putative protein kinases have been obtained from cucumber hypocotyls. The abundance of the transcript of one of these genes, which was named CsPK3, increased on treatment with gibberellin (GA4) and/or auxin (IAA). We screened a cucumber cDNA library to clone CsPK3 cDNA. The cDNA clone (cCsPK3) encodes an open reading frame of 1,413 bp (471 amino acids), and its predicted amino acid sequence showed homology with those of serine/threonine protein kinases. Northern blot analysis indicated that IAA was more active than GA4 in increasing the level of CsPK3 mRNA in cucumber hypocotyls and that the increase in the level of CsPK3 mRNA on treatment with IAA was not inhibited by pretreatment with a protein synthesis inhibitor. The level of CsPK3 mRNA was high in hypocotyls of dark-grown cucumber seedlings and decreased to less than 50% of the original level within 15 min of the start of irradiation with white light.

Minimum light intensity required to suppress nocturnal melatonin concentration in human saliva

We set out to determine the minimum intensity of light able to suppress nocturnal melatonin levels as measured in normal human saliva. Five healthy male volunteers were exposed to light at different intensities (<10, 500, 1000, 2500, and 5000 lux) in a repeated measure design. Suppression of melatonin was dependent on both light intensity and duration of light exposure. Minimum intensities of light suppressing nocturnal melatonin levels were calculated as 393, 366, 339, and 285 lux for exposure durations of 30, 60, 90, and 120 min, respectively. Minimum effective intensity and duration of light exposure showed a linear inverse relationship. These results suggest that less intensity of light than previously reported suffices to suppress melatonin in humans, and that caution is required in interpreting studies using long exposure to dim light as a background condition.

Dose-dependent response of vestibular hair cells of guinea pigs following streptomycin ototoxiation

Although the involvement of apoptosis has been suggested in the loss of vestibular hair cells due to aminoglycosides, dose-dependent effects of aminoglycosides have not been determined. We therefore examined dose-dependent effects of streptomycin on the degeneration of hair cells of guinea pig ampullar cristae using TUNEL stain and Hoechst nuclear stain. Streptomycin induced apoptosis of hair cells in a dose-dependent manner. Even following high-dose applications, most of the affected cells showed apoptotic features. Apoptosis may therefore play a predominant role in the deletion of vestibular hair cells affected by aminoglycosides.

An alteration of ganglioside composition in cisplatin-resistant lung cancer cell line

Previously we established cell lines resistant to Adriamycin and cisplatin to elucidate the mechanisms involved in acquired drug-resistance. In this study, we investigated ganglioside composition in drug-resistant cell lines. The Adriamycin-resistant cell line, SBC-3/ADM100, exhibited a ganglioside composition ratio similar to that of the parent SBC-3 cells. Densitometric analysis by resorcinol showed a 1.61-fold increase of ganglioside GM2 in SBC-3/ADM100 cells, when compared to the parent SBC-3 cells. The cisplatin-resistant cell line, SBC-3/CDDP, showed a simplified ganglioside pattern, expressing only gangliosides GM3 and GM2. SBC-3/CDDP cells showed a marked increase in ganglioside GM3. These findings suggest that the alteration of ganglioside composition may be actively involved in the acquisition of drug-resistance.

Apoptosis of guinea pig cochlear hair cells following chronic aminoglycoside treatment

Although aminoglycosides have been investigated for their cochleotoxicity, it has still not been determined whether apoptosis or necrosis results in cochlear hair cell death following aminoglycoside treatment. To study possible mechanisms of cell death, we used in situ DNA break-labeling to examine guinea pig cochleae affected by Kanamycin ototoxicity. Chronic kanamycin treatment induced DNA fragmentation that was detectable in both outer and inner hair cells, suggesting the occurrence of apoptosis. These findings suggest that apoptosis achieves deletion of affected hair cells without disrupting tissue architecture in the organ of Corti.

IL-12 receptor (IL-12R) expression and accumulation of IL-12R beta 1 and IL-12R beta 2 mRNAs in CD4+ T cells by costimulation with B7-2 molecules

IL-12 is a crucial cytokine for the determination of a Th1/Th2 balance. It is important, therefore, to elucidate the mechanisms of IL-12R expression on Th cells. In this report, we present evidence to show that B7-2 costimulation plays a pivotal role in the expression of IL-12R on Th cells. A Th1 clone expressed a low density of IL-12R in a resting condition, the expression was enhanced by stimulation with specific Ag on splenic adherent cells and the enhancement was inhibited by anti-B7-2 or CTLA-4-Ig. When stimulated with anti-CD3 plus B7-2-transfected Chinese hamster ovary (CHO) cells, the clone strongly expressed IL-12R, although anti-CD3 by itself only weakly enhanced the expression. We obtained results that were similar to those in the Th1 clone in CD4+ CD45RB(low) memory T cells. In CD4+ CD44(low) naive T cells, costimulation with B7-2-CHO was found to play a more important role in IL-12R expression. The accumulation of both IL-12R beta 1 and -beta 2 chain mRNAs was detected in naive T cells only when they were costimulated with anti-CD3 and B7-2-CHO, but beta 2 mRNA was not expressed upon anti-CD3 stimulation alone. On the other hand, both Th1 clones and memory T cells expressed low amounts of these mRNA without any stimulation, and the expression was weakly enhanced by anti-CD3 stimulation alone. For the maximum expression of these mRNAs, however, these cells also required costimulation with anti-CD3 and B7-2-CHO.

Spontaneous biloma as a complication of small cell lung cancer

Biloma is an extraductular collection of bile within a defined capsular space. Prior reports have documented an association between biloma and abdominal trauma, and between biloma and iatrogenic injury resulting from abdominal surgery, percutaneous catheter drainage, or transhepatic cholangiogram. To our knowledge, bilomas have not previously been associated with lung cancer. We report a case of spontaneous biloma that developed as a complication of small cell lung cancer.

Two modes of auditory hair cell loss following acoustic overstimulation in the avian inner ear

To determine the type of cell death occurring and how the removal of damaged cells proceeds following overstimulation, we examined chick basilar papillae using an in situ DNA nick end labeling method and transmission electron microscopy. Two distinct modes of hair cell loss were identified. First, hair cells which had not progressed into typical cell death processes, apoptosis or necrosis, were deleted by extrusion from the epithelium just after sound exposure. Second, hair cells manifested degeneration through the process of apoptosis, then further deterioration within the epithelium after the beginning of the process of hair cell regeneration. The latter mode may contribute to the following repair processes.

Differential effects of LPS and CD40 ligand stimulations on the induction of IL-12 production by dendritic cells and macrophages

In this experiment, we have examined the IL-12 production of murine macrophages (Mphi) and dendritic cells (DC) in response to LPS and CD40 ligand (CD40L) stimulations. Splenic Mphi and DC were purified by sorting on the basis of Mac-1 and CD11c expression and stimulated with LPS or Chinese hamster ovary cells expressing CD40L. The results showed that the ligation of CD40 induced the enhancement of IL-12 p40 mRNA accumulation and IL-12 production in DC as well as in Mphi; however, neither the accumulation of IL-12 p40 mRNA nor the production of bioactive IL-12 was detected in DC stimulated with various concentrations of LPS, although Mphi produced IL-12 on LPS stimulation. There was a remarkable difference in the expression of LPS receptor CD14 between Mphi and DC. Mphi evidently expressed CD14 but the CD14 expression of DC was quite low. Possible mechanisms of the failure in IL-12 production of DC are discussed.

Direct intracerebral invasion from skull metastasis of large cell lung cancer

A 56-year-old Japanese woman was referred to us for the treatment of lung cancer. On admission, the patient showed multiple bone metastases, including the skull, without brain metastasis. During chemoradiotherapy for the primary tumor and bone metastasis involving the thoracic spine, she suffered a fatal intracerebral hemorrhage. Since the patient had no risk factors for intracerebral hemorrhage, the skull bone metastasis was thought to be responsible for this event. At autopsy, penetration of the metastatic tumor from the skull bone into the dura, with direct invasion of the brain tissue, was confirmed histologically. A hematoma also was identified at the same site adjacent to the skull bone metastasis. To our knowledge, direct tumor invasion to the brain from a skull metastasis of non-small cell lung cancer has not been previously reported.

Cloning and characterization of genes encoding an enzyme which oxidizes dimethyl sulfide in Acinetobacter sp. strain 20B

Acinetobacter sp. strain 20B was isolated based on the ability to utilize dimethyl sulfide as the sole sulfur source. Since strain 20B oxidized indole as well as dimethyl sulfide, indigo production by recombinant Escherichia coli clones carrying Acinetobacter DNA was used as a selection for cloning genes encoding dimethyl sulfide oxidation genes. The gene encoding an indole-oxidizing enzyme was also found to oxidize dimethyl sulfide. The dimethyl sulfide-oxidizing enzyme genes consisted of six open reading flames designated dsoABCDEF. The deduced amino acid sequences of dsoABCDEF were homologous with those of the multicomponent phenol hydroxylases. DsoABCDEF oxidized dimethyl sulfide to dimethyl sulfoxide, and dimethyl sulfoxide to dimethyl sulfone.

The product of a gas6 splice variant allows the release of the domain responsible for Axl tyrosine kinase receptor activation

The product of gas6 (Gas6) is a growth factor with high level of similarity to protein S and was identified as the ligand for Axl family of tyrosine kinase receptors. Gas6 contains an N-terminal gamma-carboxylated domain (Gla), four epidermal growth factor like domains and a large C-terminal D region. An alternative Gas6 spliced form (Gas6SV) having an additional 43 amino acids between fourth EFG like and D domain was characterised. Here we show data indicating that Gas6SV is specifically cleaved within the inserted sequence, thereby splitting the D domain from the remaining part of the protein. The resulting two proteolytic products of 36 kDa and 50 kDa were separated and the 50 kDa fragment corresponding to region D was shown to be responsible for Axl receptor activation. Furthermore a deletion mutant of Gas6 containing only the D domain was shown to similarly activate Axl receptor phosphorylation unequivocally demonstrating that D domain can act as a signalling molecule. The possible roles of the proteolytic processing of Gas6SV in the regulation of growth factor availability are discussed.

Small cell lung cancer can express CD34 antigen

In humans CD34 is a valid and reliable marker for hematopoletic stem and progenitor cells. In general, solid tumors, with the exception of endothelial cancers, do not express CD34. Accordingly, immunological selection of CD34+ hematopoietic stem/progenitor cells can be used to remove CD34- malignant cells in the setting of autotransplantation. To rule out CD34 expression on tumor cells from small cell lung cancer (SCLC), eleven SCLC cell lines were analyzed by flow cytometry. Interestingly, two of these were positive for CD34 and their expression of full-length CD34 was further confirmed by reverse transcriptase and polymerase chain reaction (RT-PCR). This finding indicates that prior to subjecting SCLC patients to the above treatment modality, preparing CD34+ hematopoietic stem/progenitor cells from SCLC patients for autotransplantation, CD34 expression on their tumor cells should be screened using immunohistochemistry and/or flow cytometry.

Identification and characterization of genes encoding carbazole 1,9a-dioxygenase in Pseudomonas sp. strain CA10

Nucleotide sequence analysis of the flanking regions of the carBC genes of Pseudomonas sp. strain CA10 revealed that there were two open reading frames (ORFs) ORF4 and ORF5, in the upstream region of carBC. Similarly, three ORFs, ORF6 to ORF8, were found in the downstream region of carBC. The deduced amino acid sequences of ORF6 and ORF8 showed homologies with ferredoxin and ferredoxin reductase components of bacterial multicomponent dioxygenase systems, respectively. ORF4 and ORF5 had the same sequence and were tandemly linked. Their deduced amino acid sequences showed about 30% homology with large (alpha) subunits of other terminal oxygenase components. Functional analysis using resting cells harboring the deleted plasmids revealed that the products of ORF4 and -5, ORF6, and ORF8 were terminal dioxygenase, ferredoxin, and ferredoxin reductase, respectively, of carbazole 1,9a-dioxygenase (CARDO), which attacks the angular position adjacent to the nitrogen atom of carbazole, and that the product of ORF7 is not indispensable for CARDO activity. Based on the results, ORF4, ORF5, ORF6, and ORF8 were designated carAa, carAa, carAc, and carAd, respectively. The products of carAa, carAd, and ORF7 were shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be polypeptides with molecular masses of 43, 36, and 11 kDa, respectively. However, the product of carAc was not detected in Escherichia coli. CARDO has the ability to oxidize a wide variety of polyaromatic compounds, including dibenzo-p-dioxin, dibenzofuran, biphenyl, and polycyclic aromatic hydrocarbons such as naphthalene and phenanthrene. Since 2,2',3-trihydroxydiphenyl ether and 2,2',3-trihydroxybiphenyl were identified as metabolites of dibenzo-p-dioxin and dibenzofuran, respectively, it was considered that CARDO attacked at the angular position adjacent to the oxygen atom of dibenzo-p-dioxin and dibenzofuran as in the case with carbazole.

Cloning of genes involved in carbazole degradation of Pseudomonas sp. strain CA10: nucleotide sequences of genes and characterization of meta-cleavage enzymes and hydrolase

The DNA fragment encoding meta-cleavage enzymes and the meta-cleavage compound hydrolase, involved in carbazole degradation, was cloned from the carbazole-utilizing bacterium Pseudomonas sp. strain CA10. DNA sequence analysis of this 2.6-kb SmaI-SphI fragment revealed that there were three open reading frames (ORF1, ORF2, and ORF3, in this gene order). ORF1 and ORF2 were indispensable for meta-cleavage activity for 2'-aminobiphenyl-2,3-diol and its easily available analog, 2,3-dihydroxybiphenyl, and were designated carBa and carBb, respectively. The alignment of CarBb with other meta-cleavage enzymes indicated that CarBb may have a non-heme iron cofactor coordinating site. On the basis of the phylogenetic tree, CarBb was classified as a member of the protocatechuate 4,5-dioxygenase family. This unique extradiol dioxygenase, CarB, had significantly higher affinity and about 20-times-higher meta-cleavage activity for 2,3-dihydroxybiphenyl than for catechol derivatives. The putative polypeptide encoded by ORF3 was homologous with meta-cleavage compound hydrolases in other bacteria, and ORF3 was designated carC. The hydrolase activity of CarC for 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid, the meta-cleavage compound of 2,3-dihydroxybiphenyl, was 40 times higher than that for 2-hydroxy-6-oxohepta-2,4-dienoic acid, the meta-cleavage compound of 3-methylcatechol. Alignment analysis and the phylogenetic tree indicate that CarC has greatest homologies with hydrolases involved in the monoaromatic compound degradation pathway. These results suggest the possibility that CarC is a novel type of hydrolase.

Triggers of hair cell regeneration in the avian inner ear

We performed an in vitro study in order to determine possible triggers of hair cell regeneration in the chick basilar papilla following degeneration. We compared the response of sensory epithelium damaged by collagenase treatment with that damaged by acoustic trauma. The former exhibited no proliferative activity, but the latter did. The basilar papillae damaged by acoustic trauma could have proliferating activity in medium containing fetal bovine serum (FBS) or epidermal growth factor (EGF) but not in the medium without FBS or EGF. These findings indicate that regeneration of basilar papillae depends on the manner of cell death and that FBS or EGF is required for regeneration.

Temporal bone pathology of a patient with cochlear implant

A 66-year-old man with profound total deafness received a 22-channel cochlear implant. After surgery, his hearing improved and the postoperative course was uneventful except transient vertigo. The patient died of lung cancer after 2.5 years. Twelve hours after death, the temporal bone was harvested for histological and electron microscopic examination. The mastoid air cells were preserved, although a few mucosal folds were present. The Dacron mesh tie had largely been absorbed, but part remained embedded in fibrous tissue. No inflammation was noted in the tympanic cavity or the round window through which the electrodes were inserted. In the cochlea, the scala tympani was filled with fibrous tissue at the site of electrode insertion. The scala media had collapsed, while the organ of Corti and stria vascularis showed degeneration. Osseous spiral bundles and spiral ganglion cells were noted, though reduced in number.

Nitric oxide synthase and contractile protein in the rat cochlear lateral wall: possible role of nitric oxide in regulation of strial blood flow

The present study demonstrated by histochemical and immunohistochemical methods that NADPH diaphorase reactivity, endothelial nitric oxide synthase (eNOS)-like immunoreactivity, and tropomyosin-like immunoreactivity, were located within the rat cochlear lateral wall. Both NADPH diaphorase reactivity and eNOS-like immunoreactivity were found mainly in the endothelium of the strial capillaries (ESC) and that of the vessels of the spiral ligament (ESL). These reaction products appeared to be somewhat more common in the ESC than in the ESL. On the other hand, tropomyosin-like immunoreactivity was localized in tissues outside the endothelium and its intensity was greater in the ESL than in the ESC. These findings suggest that nitric oxide (NO) produced by eNOS may play a role in regulating the blood flow of the cochlear lateral wall. In addition, NADPH diaphorase reactivity, eNOS-like immunoreactivity, and tropomyosin-like immunoreactivity showed different patterns of distribution between ESC and ESL. This suggests that in these two sites blood circulation is controlled by NO through two different mechanisms that are suitable for regulating strial blood flow.

Identification of stylar RNases associated with gametophytic self-incompatibility in almond (Prunus dulcis)

Stylar proteins of 13 almond (Prunus dulcis) cultivars with known S-genotypes were surveyed by IEF and 2D-PAGE combined with immunoblot and N-terminal amino acid sequence analyses to identify S-RNases associated with gametophytic self-incompatibility (SI) in this plant species. RNase activities corresponding to Sa and Sb, two of the four S-alleles tested, were identified by IEF and RNase activity staining. The Sa-RNase band reacted with the anti-S4-serum prepared from Japanese pear (Pyrus serotina); no reaction with the antiserum was observed with the Sb-RNase band. When the Sa-RNase band was excised from an IEF gel stained for RNase activity, subjected to SDS-PAGE, and detected by immunoblotting, it appeared that this band consisted of a single protein that reacted with the anti-S4-serum with M(r) of about 28 kDa. With 2D-PAGE and silver staining of the stylar extracts, all four S-proteins could be successfully distinguished from each other in the highly basic zone of the gel. Although Sb-, Sc-, and Sd-proteins had roughly the same M(r) of about 30 kDa, the Sc-protein seemed to be slightly smaller than the Sb-protein and slightly larger than the Sd-protein. In 2D-PAGE profiles as well, the Sa-protein had M(r) of about 28 kDa, apparently smaller than the other three proteins. A bud sport, in which one of the two S-alleles of the original cultivar is impaired, was visualized as a loss of Sc-protein, which is consistent with the previous pollination study. All four S-proteins reacted with the anti-S4-serum, probably because of the differing conformations of these S-proteins in the IEF and 2D-PAGE gels. The Sa-protein in 2D-PAGE appeared to be identical to Sa-RNase in IEF; both had the same M(r) and were reactive with the anti-S4-serum. N-terminal amino acid sequence analysis of the four S-proteins revealed that they were highly homologous to each other and similar to the S-RNases of Malus, Pyrus, Scrophulariaceae, and Solanaceae. Taken together, RNases in the style are strongly suggested to be associated with the gametophytic SI of almond. This is the first report identifying and characterizing S-RNase in almond.

Biosynthesis of GA73 Methyl Ester in Lygodium Ferns

Biosynthesis of GA73 methyl ester (GA73-Me), the principal antheridiogen in Lygodium ferns, was investigated. From the methanol extract of prothallia of Lygodium circinnatum, GA25, GA73, GA73-Me, GA88-Me, and a few unknown GA73 derivatives were detected by GC-MS. Because the presence of GA25 suggests that GA24, a direct precursor of GA25, could also be present in L. circinnatum prothallia, we used feeding experiments to investigate the possibility that GA24 is a precursor of GA73-Me. In L. circinnatum prothallia, [2H2]GA24 was converted into [2H2]GA73-Me and a trace amount of [2H2]GA9-Me, whereas [2H3]GA9 was converted into [2H3]GA9-Me and [2H3]monohydroxy-GA9-Me. Because GA73-Me, GA9-Me, and their monohydroxy derivatives had been identified by GC-MS from the culture medium of L. circinnatum prothallia, our results suggest that GA73-Me is biosynthesized from GA24 via GA73, and that neither GA9 nor GA9-Me is a precursor of GA73-Me. Though the possibility had been suggested that GA73-Me is biosynthesized from 9,15-cyclo-GA9 (GA103), [2H2]GA103 was not converted into [2H2]GA73-Me.

Subunit Ya-specific glutathione peroxidase activity toward cholesterol 7-hydroperoxides of glutathione S-transferases in cytosols from rat liver and skin

Dermal 7alpha- and 7beta-hydroperoxycholest-5-en-3beta-ols (cholesterol 7alpha- and 7beta-hydroperoxides), regarded as good aging markers in the rat (Ozawa, N., Yamazaki, S., Chiba, K., Aoyama, H., Tomisawa, H., Tateishi, M., and Watabe, T. (1991) Biochem. Biophys. Res. Commun. 178, 242-247), were reduced in the presence of glutathione (GSH) with concomitant formation of GSSG by cytosol from rat liver in which no detectable level of the hydroperoxides had been demonstrated to occur. The GSH peroxidase (GSH Px) activity toward the toxic steroid hydroperoxides was exerted to almost the same extent by both Alpha-class GSH S-transferases (GSTs), Ya-Ya and Ya-Yc, and by selenium-containing GSH Px (Se-GSH Px) in rat liver cytosol. None of three Mu-class GSTs, Yb1-Yb1, Yb1-Yb2, and Yb2-Yb2, and a Theta-class GST, Yrs-Yrs, from rat liver and a Pi-class GST, Yp-Yp, from rat kidney showed any appreciable GSH Px activity toward the hydroperoxides. The subunit Ya-bearing GSTs and Se-GSH Px purified from rat liver cytosol showed marked differences in apparent specific activity toward the cholesterol hydroperoxides (GSTs Ya-Ya > Ya-Yc >> Se-GSH Px). However, a kinetic study indicated that Se-GSH Px had a higher affinity for steroid hydroperoxides than did the GSTs, so that Se-GSH Px could catalyze the reduction of lower concentrations of cholesterol 7-hydroperoxides with approximately equal Vmax/Km values to those by the GSTs. Rat skin had no GST bearing the subunit Ya but contained only a very low concentration of Se-GSH Px, possibly resulting in the accumulation of cholesterol 7-hydroperoxides in the skin but not in the liver. From rat skin cytosol, GSTs Yc-Yc, Yb1-Yb1, Yb1-Yb2, Yb2-Yb2, and Yp-Yp were isolated, purified to homogeneity, and identified with the corresponding GSTs from liver and kidney. The GSTs accounted for 0.23% of total skin cytosolic protein, and the most abundant isoform of skin GSTs was Yb2-Yb2, followed by Yc-Yc, Yp-Yp, Yb1-Yb1, and Yb1-Yb2 in decreasing order.

Cell death caused by the acute effects of aminoglycoside and zinc in the ampullary cristae of guinea pigs

We reported that apoptosis occurred in the guinea pig vestibular hair cells after chronic aminoglycoside treatments. In the present study, we used in situ nick-end labeling to determine whether apoptosis was also induced by the acute effects of aminoglycosides in guinea pig ampullar cristae. In addition, we evaluated the effect of zinc supplements upon these ototoxic treatments. After a local application of streptomycin directly to the round window, we found labeled bodies in the vestibular hair cells. The zinc supplement increased the number of labeled bodies resulting in severe hair cell loss. These findings indicate that the acute effects of aminoglycosides also induce apoptosis of the vestibular hair cells, and that zinc enhances aminoglycoside ototoxicity. Consequently, we propose that an interaction with ion channels may play a key mechanism in the processes of apoptosis affecting the vestibular hair cells.

Induction of free radicals in the cochlea by an aminoglycoside antibiotic

Free radicals are known to cause damage to biological tissues. We used histochemical methods to examine the emergence of free radicals in kanamycin (KM)-treated guinea pig cochlea. As a preliminary in vitro study, the emergence of free radicals was observed in guinea pig cochlea incubated with KM. In an in vivo study, KM was placed on the guinea pig round window membrane and the emergence of free radicals was observed over time. The emergence of free radicals was observed along the luminal membrane and hair bundles of outer hair cells. The appearance and disappearance of free radicals in the cochlea coincided with the transport of KM into the inner ear. These findings suggest that the emergence of free radicals could be attributed to the administration of KM.

Gentamicin ototoxicity induced apoptosis of the vestibular hair cells of guinea pigs

To clarify mechanisms of inner ear cell death induced by aminoglycosides, we used an in situ nick-end labelling method to examine guinea pig vestibular epithelia after chronic systemic treatments with gentamicin to produce apoptosis. Such changes occurred in damaged hair cells, suggesting that this process may be crucial for subsequent repair and cell regeneration.

Asialo GM1-positive cells in mouse cochlea

The presence of ganglio-N-tetraosylceramide (asialo GM1)-positive cells in mouse cochlea was tested for using an immunohistochemical method with an anti-asialo GM1 antibody which reacts with natural killer cells and macrophages in mouse. Only a few asialo GM1-positive cells were present on the surface of the scala tympani of the basal turn near the collecting venules. Transmission electron microscopic study showed the internal structure of these cells to be that of macrophages. These findings suggest that asialo GM1-positive cells function as resident type macrophages against invasion by pathogens of the mouse cochlea.

Analysis of cumene (isopropylbenzene) degradation genes from Pseudomonas fluorescens IP01

We obtained the DNA fragments encoding 2-hydroxy-6-oxo-7-methylocta-2,4-dienoic acid (HOMODA) hydrolase in the cumene (isopropylbenzene) degrader Pseudomonas fluorescens strain IP01 via PCR using two synthesized oligonucleotides corresponding to the conserved regions within known meta-cleavage compound hydrolases. Following colony hybridization using the amplified DNA as a probe, a 4.5-kb HindIII fragment was isolated from P. fluorescens IP01. After determining the nucleotide sequence of this fragment, three open reading frames (ORF11 [cumH], ORF12 [cumD], and ORF13) were identified. The deduced amino acid sequence of ORF12 showed homology with meta-cleavage compound hydrolases encoded by the tod, dmp, xyl, and bph operons. Although the product of ORF12 was found to exhibit HOMODA and 2-hydroxy-6-oxohepta-2,4-dienoic acid (HOHDA) hydrolase activities, it did not exhibit 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoic acid (HOPDA) hydrolase activity. The deduced amino acid sequence of ORF11 showed 40.4% homology with the sequence of todX in Pseudomonas putida F1 (Y. Wang, M. Ralings, D. T. Gibson, D. Labbé, H. Bergeron, R. Brousseau, and P. C. K. Lau, Mol. Gen. Genet. 246:570-579, 1995). The nucleotide sequence of ORF13 and its flanking region showed strong homology (91.0%) with IS52 from Pseudomonas savastanoi (Y. Yamada, P.-D. Lee, and T. Kosuge, Proc. Natl. Acad. Sci. USA 83:8263-8267, 1982). By characterization of cumH and cumD, the entire cum gene cluster from the cumene-degrader P. fluorescens IP01 (cumA1A2A3A4BCEGFHD) has been identified.

[Chemotherapy for small-cell lung cancer]

Here we review the current treatments for small-cell lung cancer. Cisplatin and etoposide, combined with concurrent or alternating thoracic irradiation, have been considered to be the standard therapy for patients with limited disease. Dose-intensive weekly chemotherapy and high-dose chemotherapy with autologous stem cell transplantation have failed to increase survival in patients with extensive disease. Promising new drugs such as irinotecan and taxol may improve survival in patients with extensive disease.

Sphingosine inhibition of NADPH oxidase activation in a cell-free system

The effects of sphingoid bases, sphingosine and dihydrosphingosine, which are protein kinase C (PKC) inhibitors, on NADPH oxidase were examined in a cell-free system. The bases inhibited cell-free activation of NADPH oxidase by arachidonic acid at lower concentration than N-acetylsphingosine. Thus, positive charge in the molecules may play a critical role in inhibition of the oxidase. Sphingosine did not change the Km value for NADPH, but shifted the optimum concentration of arachidonic acid for activation of the oxidase. Moreover, sphingosine suppressed the translocation of p47-phox, one of the cytosolic components of the oxidase, to the membrane fraction, suggesting that the base inhibits the assembly of the components.

Molecular cloning and characterization of a cDNA encoding the gibberellin biosynthetic enzyme ent-kaurene synthase B from pumpkin (Cucurbita maxima L.)

The first committed step in the formation of diterpenoids leading to gibberellin (GA) biosynthesis is the conversion of geranylgeranyl diphosphate (GGDP) to ent-kaurene. ent-Kaurene synthase A (KSA) catalyzes the conversion of GGDP to copalyl diphosphate (CDP), which is subsequently converted to ent-kaurene by ent-kaurene synthase B (KSB). A full-length KSB cDNA was isolated from developing cotyledons in immature seeds of pumpkin (Cucurbita maxima L.). Degenerate oligonucleotide primers were designed from the amino acid sequences obtained from the purified protein to amplify a cDNA fragment, which was used for library screening. The isolated full-length cDNA was expressed in Escherichia coli as a fusion protein, which demonstrated the KSB activity to cyclize [3H]CDP to [3H]ent-kaurene. The KSB transcript was most abundant in growing tissues, but was detected in every organ in pumpkin seedlings. The deduced amino acid sequence shares significant homology with other terpene cyclases, including the conserved DDXXD motif, a putative divalent metal ion-diphosphate complex binding site. A putative transit peptide sequence that may target the translated product into the plastids is present in the N-terminal region.

cDNA cloning and characterization of a gibberellin-responsive gene in hypocotyls of Cucumis sativus L

A cDNA clone corresponding to a gibberellin-responsive gene (CRG16) was isolated from cucumber hypocotyls. CRG16 was deduced to encode an extremely hydrophobic protein of 65 amino acids. The deduced sequence exhibited no significant homology to other proteins. Levels of CRG16 mRNA reflected the gibberellin-induced elongation of cucumber hypocotyls.