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Biomedical subjects

T Shono

Publications and source records attributed to T Shono.

At least 55 records · Page 3Linked to original sources
PubMed1999

Silver and thallium(I) complexation with dibenzo-16-crown-4.

Dibenzo-16-crown-4 (1) indicates high silver and thallium(I) ion selectivity over sodium, potassium, and rubidium ion evaluated from the solvent extraction of metal picrates, while its cation-binding ability is lower than those of dibenzo-18-crown-6 (2) and dibenzo-22-crown-6 (3). Taking account of the highest thallium(I) ion selectivity for 1 obtained from extraction experiments, PVC membrane thallium(I)-selective electrodes based on 1 are prepared. The electrode shows the best potentiometric selectivity coefficients for thallium(I) over potassium and rubidium than those of 2 and 3, and commercially available bis(crown ether)s (4).

Crown Ethers↗
PubMed1999

Anisatin modulation of the gamma-aminobutyric acid receptor-channel in rat dorsal root ganglion neurons.

1. Anisatin, a toxic, insecticidally active component of Sikimi plant, is known to act on the GABA system. In order to elucidate the mechanism of anisatin interaction with the GABA system, whole-cell and single-channel patch clamp experiments were performed with rat dorsal root ganglion neurons in primary culture. 2. Repeated co-applications of GABA and anisatin suppressed GABA-induced whole-cell currents with an EC50 of 1.10 microM. No recovery of currents was observed after washout with anisatin-free solution. 3. However, pre-application of anisatin through the bath had no effect on GABA-induced currents. The decay phase of currents was accelerated by anisatin. These results indicate that anisatin suppression of GABA-induced currents requires opening of the channels and is use-dependent. 4. Anisatin suppression of GABA-induced currents was not voltage dependent. 5. Picrotoxinin attenuated anisatin suppression of GABA-induced currents. [3H]-EBOB binding to rat brain membranes was competitively inhibited by anisatin. These data indicated that anisatin bound to the picrotoxinin site. 6. At the single-channel level, anisatin did not alter the open time but prolonged the closed time. The burst duration was reduced and channel openings per burst were decreased indicating that anisatin decreased the probability of openings.

Affinity Labels↗
PubMed1999

Induction of gene expression of antibacterial proteins by chitin oligomers in the silkworm, Bombyx mori.

Activation of antibacterial protein genes by various chitin oligomers (from dimer to hexamer) was investigated by Northern blot analysis using cDNAs encoding cecropin B, attacin and lebocin from Bombyx mori as probes. All chitin oligomers tested were found to strongly trigger expression of cecropin B, attacin and lebocin genes. Furthermore, gene expression triggered by chitin oligomers was confirmed to occur specifically in the fat body and haemocytes. These results suggest that chitin oligomers have the same characteristics as those of lipopolysaccharide (LPS) and peptidoglycan in triggering gene expression of insect antibacterial proteins.

Animals↗
PubMed1999

Does maternal stress induce abnormal descent of the testis in prepubertal rats?

OBJECTIVE: To investigate whether prenatal maternal stress, considered to alter plasma testosterone concentration and induce a lack of testosterone surge in male rat fetuses, has any effect on the growth of the processus vaginalis and testicular descent in male offspring. MATERIALS AND METHODS: Pregnant rats were divided into two groups. In group 1, the rats were placed three times daily for 60 min each session in Plexiglas rat holders (13x6x8 cm) illuminated by two 150-W flood lights from day 14 to day 18 of gestation during the dark phase of the animals' light (12 h) and dark (12 h) cycle. In group 2, pregnant females were not handled and acted as controls. After birth, the anogenital distance of both the male and female rats was measured, and the length of the processus vaginalis was measured at 7 days of age in some rats. Thereafter, at 21, 24, 27 and 30 days of age, testicular descent was assessed in the remaining male rats. RESULTS: In group 1, at 21, 24, 27 days of age, testicular descent was delayed in the stressed rats compared with the control rats. At 30 days of age, five of 36 stressed male offspring showed abnormal testicular descent; three testes were in the superficial inguinal position and two were above the scrotum. Both the anogenital distance and the length of the processus vaginalis were significantly less in the stressed male rats than in the controls. CONCLUSIONS: Maternal stress induced a female-like anogenital distance in male rat fetuses, and caused delayed and abnormal descent of the testis, by inhibiting the growth of the processus vaginalis after birth. Prenatal stress may therefore be involved in the delay of testicular descent in neonatal rats by inducing a mild anti-androgenic effect in the fetus.

Animals↗
PubMed1999

Does proximal genitofemoral nerve division induce testicular maldescent or ascent in the rat?

OBJECTIVE: To investigate whether the division of the proximal genitofemoral nerve (GFN) in neonatal rats induces testicular undescent or ascent in adulthood. MATERIALS AND METHODS: Neonatal Wistar King A rats underwent a unilateral proximal GFN transection on either the right or left side. At the age of 30 days, testicular descent was examined in all rats and the position of the testis recorded. The animals were allowed to develop further and the position of the testis re-examined at the age of 90-180 days, when the testes were removed and weighed. Sham-operated rats were used as controls. RESULTS: At the age of 30 days, four of the 46 (9%) operated rats showed a unilateral undescended testis on the operated side. At the age of 90-180 days, 43 rats were re-examined (three rats died before re-examination); 34 (79%) of these rats showed undescended testes on the operated side. The occurrence of cryptorchidism was significantly higher in the 90-180-day-old mature rats than in 30-day-old prepubertal rats (P<0.01). The mean (sd) weight of the undescended testes, at 2.36 (0.21) mg/g body weight, was significantly less than that of the contralateral scrotal testes, at 3.83 (0.23) mg/g; P<0.01) and of the control testes at the age of 90-180 days. In the sham-operated rats, all testes were located at the bottom of the scrotum at 30 days of age and no rats showed any testicular ascent thereafter. CONCLUSIONS: The proximal division of the GFN in neonatal rats not only causes inguinoscrotal testicular maldescent but may also induce testicular ascent in adulthood. Testicular ascent may thus be caused by some intrauterine disorders of the GFN in patients with ascending testis.

Animals↗
PubMed1999

Pituitary abscess secondary to isolated sphenoid sinusitis.

Intracranial complications from isolated sphenoid sinusitis are rare but nevertheless demonstrate both a high morbidity and mortality. We herein report a case of a pituitary abscess secondary to sphenoid sinusitis in a 12-year-old boy. This patient presented with an acute onset of moderate fever and headache, followed by progressive right ptosis. An emergency endoscopic endonasal sphenoidotomy with sinus drainage and postoperative antibiotic therapy resulted in a satisfactory recovery.

Brain Abscess↗
PubMed1999

Paraganglioma of the urinary bladder: A case report and review of the Japanese literature.

We describe a patient with primary paraganglioma of the urinary bladder associated with typical clinical symptoms. Systolic blood pressure frequently increased to 300 mm Hg immediately after micturition. Levels of urinary vanillylmandelic acid excretion and serum norepinephrine were significantly elevated. The tumor was removed by partial cystectomy. Histological examination of the tumor revealed paraganglioma of the urinary bladder. Compared with a review of 53 similar cases reported in Japan, the distribution of age, sex and tumor location in the bladder differed from those described worldwide.

Cystectomy↗
PubMed1999

Macrophage infiltration and heme oxygenase-1 expression correlate with angiogenesis in human gliomas.

Macrophages are key participants in angiogenesis. In this study on human brain tumors, we first investigated whether macrophage infiltration is associated with angiogenesis and malignant histological appearance. Immunostaining of macrophages and small vessels in resected glioma specimens indicated that numbers of infiltrating macrophages and small vessel density were higher in glioblastomas than in astrocytomas or anaplastic astrocytomas. Macrophage infiltration was closely correlated with vascular density in human gliomas. Heme oxygenase-1 (HO-1), which is the rate-limiting enzyme in heme catabolism, was also associated with activated macrophages. Expression of mRNA encoding HO-1 was correlated with macrophage infiltration and vascular density in human glioma samples. Infiltrating macrophages were positively stained with anti-HO-1 antibody by immunohistochemical analysis, and in situ hybridization for HO-1 indicated that HO-1 was expressed in infiltrating macrophages in gliomas. HO-1 gene may be a useful marker for macrophage infiltration as well as neovascularization in human gliomas.

Adolescent↗
PubMed1999

[Influence of scalp shaving on prevention of postoperative intracranial infection].

Shaving of the whole scalp is ordinarily performed prior to neurosurgical operation. Although it is performed in order to prevent postoperative intracranial infection, there has been no apparent basis for this practice published in previous reports. We examined whether shaving the whole scalp reduced the rate of postoperative infection or not. We divided 274 cases, who received their first intracranial operation in the last 2 years, into two groups; a whole shaving group and a partial shaving group. We compared the rate of postoperative intracranial infection between the two groups according to age, diagnosis, operation, operation time and placement of drainage. Overall, 12 cases out of 274 (4.38%) had postoperative intracranial infection. The long operation time and the long term placement of drainage mechanism increased the postoperative intracranial infection rate. There was no postoperative intracranial infection in 74 patients who received burr-hole/twist-drill operation. As for craniotomy/craniectomy operations, 7 cases out of 83 (8.4%) in the partial scalp-shaving group whole scalp shaving group and 5 cases out of 117 (4.2%) had postoperative intracranial infections. Thus, there was no significant difference in the rate of postoperative intracranial infection between the two groups, if anything, the whole scalp shaving group tended to show a higher rate. According to these results, partial scalp shaving did not increase the rate of postoperative intracranial infection. Considering that patients who have lost their hair find it embarrassing to return to society, it is well to know that the whole scalp shaving is not absolutely necessary for all first craniotomy.

Craniotomy↗
PubMed1998

Dieldrin and picrotoxinin modulation of GABA(A) receptor single channels.

The insecticide dieldrin is known to suppress the GABA(A) receptor-channel complex in a manner similar to that of picrotoxin. To elucidate the more detailed mechanisms of dieldrin and picrotoxin interactions with the GABA system, single-channel patch clamp experiments were performed using rat dorsal root ganglion neurons in primary culture. Dieldrin did not alter the open time distribution and mean current amplitude or the distribution of burst duration and the mean burst duration. However, the mean closed time was prolonged indicating that dieldrin decreased the channel open probability. Previous studies have demonstrated that dieldrin and picrotoxin share the common binding site on the GABA receptor. Thus, the effects of picrotoxinin on the GABA(A) receptor single channels were also examined. Dieldrin and picrotoxinin had similar effects at the single-channel level. These changes of single-channel parameters explain the suppressive effects of these chemicals on GABA-induced whole-cell currents.

Animals↗
PubMed1998

Novel biological functions of interleukin-4: formation of tube-like structures by vascular endothelial cells in vitro and angiogenesis in vivo.

The effect of interleukin-4 (IL-4) on angiogenesis was studied in vitro and in vivo. Human recombinant IL-4 significantly stimulated the formation of tube-like structures in collagen gels by bovine aortic endothelial cells as well as by human microvascular endothelial cells. Human recombinant IL-4 at 50-500 U/ml stimulated by about two- to threefold the formation of tubes by bovine aortic endothelial cells; the rate was comparable to that of basic fibroblast growth factor. Tube formation was almost completely inhibited by the addition of IL-4 receptor neutralizing antibody. Administration of rat recombinant IL-4 led to neovascularization when implanted in the rat cornea. Findings suggest that IL-4 may be a mediator of the immune system as well as an inducer of angiogenesis.

Animals↗
PubMed1998

In vitro metabolism of pyriproxyfen by microsomes from susceptible and resistant housefly larvae.

Levels of cytochrome P450 and b5 were investigated in microsomal enzymes of houseflies from the gut and fat body of the third instar larvae of a pyriproxyfen-resistant strain (YPPF) and two pyriproxyfen-susceptible strains (YS and SRS). In comparison to the YS and SRS strains, YPPF microsomes had higher levels of total cytochrome P450s in both the gut and fat body. Furthermore, microsomes from the gut and fat body of YPPF larvae were found to have a much greater ability to hydroxylate aniline than YS larvae. In vitro metabolism studies of pyriproxyfen indicated that the metabolic rates were much higher in both the gut and fat body of YPPF larvae than of YS and SRS larvae. The major metabolites of pyriproxyfen in houseflies were identified to be 4'-OH-pyriproxyfen and 5"-OH-pyriproxyfen. Cytochrome P450 inhibitors, piperonyl butoxide (PB) and 2-propynyl 2,3,6-trichlorophenyl ether (PTPE), decreased the metabolic rates significantly in all three strains. This study confirmed that microsomal cytochrome P450 monooxygenases play an important role in the pyriproxyfen resistance of the housefly. Furthermore, it suggests that the fat body must be as important as the gut for the metabolism of pyriproxyfen in resistant housefly larvae.

Adipose Tissue↗
PubMed1998

A new synthetic matrix metalloproteinase inhibitor modulates both angiogenesis and urokinase type plasminogen activator activity.

Proteolytic degradation of the extracellular matrix is essential to angiogenesis. Two families of proteases, the serine proteases of plasminogen activator/plasmin system and the matrix metalloproteinases (MMPs) are closely involved in these processes. The treatment of mice with a diet containing a new synthetic MMP inhibitor, OPB-3206: 3S-[4-(N-hydroxyamino)-2R-isobutylsuccinyl] amino-1methoxy-3, 4-dihydrocarbostyril, abrogated the development of new vessels in a rat corneal assay, and in a mouse Matrigel assay. In an in vitro angiogenesis model, OPB-3206 inhibited the migration and the tube formation of bovine aortic endothelial cells at 10-100 times lower concentrations than those required to inhibit the growth of these cells. OPB-3206 as well as other MMP inhibitory drugs, batimastat/BB-94 and marimastat/BB-2516, also selectively inhibited tubular morphogenesis in vitro. OPB-3206 reduced the activities of interstitial collagenase and type IV collagenase, but the concentrations of 50% inhibition against these MMPs were much higher than those of BB-94 and BB-2516. However, this new compound also inhibited urokinase type plasminogen activator activity on fibrin zymogram, while BB-94 and BB-2516 did not. Furthermore, the addition of urokinase type plasminogen activator reduced the inhibitory effect of the tubular morphogenesis of vascular endothelial cells by OPB-3206. The treatment of mice with a diet containing this new compound also reduced the growth of implanted mammary carcinomas as well as the lung metastasis of colon carcinoma. The anti-angiogenic effect of OPB-3206 appeared to be associated with its inhibition of tumor growth and metastasis.

Journal Article↗
PubMed1998

Molecular cloning and nucleotide sequence of a cytochrome P450 cDNA from a pyrethroid-resistant mosquito, Culex quinquefasciatus say.

A novel cDNA clone encoding a cytochrome P450 was screened from a gut cDNA library of permethrin-resistant Culex quinquefasciatus larvae. Nucleotide sequence of the clone designated CYP6E1 was determined. This is the first full-length sequence of a mosquito P450 cDNA. Comparison of the deduced amino acid sequence of CYP6E1 to those of other known cytochrome P450s indicates that this clone belongs to CYP6 family. In addition, a phylogenetic analysis of CYP6E1 primary structure showed that it is related to CYP6A and CYP6C subfamilies. Polymerase chain reaction (PCR) using primers designed on the basis of the nucleotide sequence of the cDNA showed that mRNA encoding CYP6E1 is present in permethrin-susceptible larvae as well as -resistant larvae, suggesting the ubiquitous distribution of CYP6E1.

Amino Acid Sequence↗
PubMed1998

Fertility and histological studies in a unilateral cryptorchid rat model during early and late adulthood.

OBJECTIVE: To investigate the effect of age on fertility and testicular development in rats with untreated unilateral undescended testes. MATERIALS AND METHODS: Newborn male Wistar King-A rats were divided into two groups. In group 1, a mechanical model of unilateral undescended testis was created by performing extra-abdominal fixation of the gubernaculum in the neonatal period, and in group 2, sham-operated rats were used as controls. At 90 days old (early adulthood), the fertility of both groups was assessed by mating the rats with mature virgin females for 2 weeks. Thereafter, some of the rats were killed and their testes examined histologically, while the remaining rats were allowed to develop further. At the age of 180 days (late adulthood), fertility was re-assessed in the same way. All the rats were then killed and their testes removed for histological examination. RESULTS: There was no significant difference in pregnancy rate of females mated with males from either group in early adulthood. However, in late adulthood there was a significant reduction in pregnancy rate in females coupled with cryptorchid rats compared with that of females coupled with control rats. There was a significant degeneration of the unilateral cryptorchid testes compared with control testes in both early and late adulthood. In contrast, there were no significant changes in histological development between the contralateral scrotal testes and the controls in early adulthood, although they were significantly different from the controls in late adulthood. CONCLUSION: These results suggest that fertility is affected by ageing in untreated unilateral cryptorchidism; this may be induced by extensive damage not only in the undescended testes, but also in the contralateral scrotal testis, in this mechanically induced model of unilateral cryptorchidism.

Aging↗
PubMed1998

Fertility and histological studies of the contralateral testes in two different intra- and extra-abdominal rat models of unilateral cryptorchidism.

OBJECTIVE: To investigate the effect of location of the testis on both testicular development and fertility in unilateral cryptorchidism. MATERIAL AND METHODS: Forty-nine Wistar King A newborn male rats were divided into three groups. In group 1 (15 rats) intra-abdominal unilateral cryptorchidism were created by the intra-abdominal fixation of the testis in the neonatal period. In group 2 (16 rats) extra-abdominal unilateral cryptorchidism was created by extra-abdominal fixation of the gubernaculum in the neonatal period. In group 3, 18 rats underwent a sham operation as controls. At 90 days of age, fertility was then assessed in each rat by housing it with two mature virgin females for 2 weeks. Thereafter, at 115-120 days of age, the rats were killed and their testes removed for histological examination. RESULTS: There was no significant difference in the pregnancy rate between females coupled with rats from any group, but the mean number of offspring was significantly lower in females coupled with rats in group 1 than in group 2. Furthermore, histological examination of both the cryptorchid and contralateral scrotal testes showed more severe changes in the intra-abdominal than the extra-abdominal testes. CONCLUSION: These results suggest that intra-abdominal cryptorchid testes are significantly more impaired than extra-abdominal cryptorchid testes, and that such impairment might be caused by exposure of the testis to a higher temperature. The more severely impaired undescended testes may thus induce the degeneration of the contralateral scrotal testis and thereby cause subfertility in the intra-abdominal unilateral cryptorchid rat model.

Animals↗
PubMed1998

Modulation of the neuronal nicotinic acetylcholine receptor-channel by the nitromethylene heterocycle imidacloprid.

Nitromethylene heterocycle insecticides are known to act on the nicotinic acetylcholine receptor-channel. The effects of the nitromethylene heterocycle, imidacloprid, on the nicotinic acetylcholine receptor-channel of clonal rat phaeochromocytoma (PC12) cells were studied using whole-cell and single-channel patch clamp methods. Imidacloprid suppressed carbachol-induced whole-cell currents in a dose-dependent manner, and this compound itself generated small currents. Multiple conductance states of single-channel currents were also evoked by imidacloprid at the nicotinic acetylcholine receptor-channels. The most frequently generated single-channel currents showed two conductance states, 25.4 and 9.8 pS, which were identical to the conductance states of acetylcholine-generated currents. The mean open time and burst duration of the main conductance currents induced by imidacloprid were shorter than those induced by acetylcholine. Co-application of imidacloprid and acetylcholine caused some interactions at the two conductance states. Mean open time and mean burst duration of the main conductance state currents evoked by acetylcholine were decreased by the co-application of imidacloprid as compared with those induced by acetylcholine alone. In conclusion, imidacloprid has both multiple agonist and antagonist effects on the neuronal nicotinic acetylcholine receptor-channels.

Acetylcholine↗