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Biomedical subjects

H Suenaga

Publications and source records attributed to H Suenaga.

At least 37 records · Page 2Linked to original sources
PubMed1999

Engineering a hybrid pseudomonad to acquire 3,4-dioxygenase activity for polychlorinated biphenyls.

We constructed a hybrid strain that acquired 3,4-dioxygenase activity for polychlorinated biphenyls (PCBs). This strain, KF707-D34, possessed a chimeric biphenyl dioxygenase gene, of which a portion of bphA1 (coding for a large subunit of biphenyl dioxygenase) of Pseudomonas pseudoalcaligenes KF707 was replaced with that of a PCB-degrader, Burkholderia cepacia LB400 by homologous recombination. KF707-D34 retained the ability to degrade 4,4'-dichlorobiphenyl via 2,3-dioxygenation in a fashion identical to that of KF707 and gained novel capability to degrade 2,5,4'-trichlorobiphenyl and 2,5,2',5'-tetrachlorobiphenyl via 3,4-dioxygenation in a fashion identical to that of LB400. Sequence analysis of bphA1 from KF707-D34 revealed that three nucleotides in the 3'-terminal region of KF707 bphA1 were changed to correspond to those in LB400 bphA1. The resulting BphA1 protein in KF707-D34 was changed at position 376 from threonine (Thr) to asparagine (Asn). The results demonstrate that a minor alteration of the amino acid sequence in BphA1 improved the PCB degradation capability in biphenyl-utilizing bacteria.

Journal Article↗
PubMed1999

Enhanced Ca2+ sensitization of the bronchial smooth muscle contraction in antigen-induced airway hyperresponsive rats.

To investigate the alteration in acetylcholine (ACh)-induced increase in Ca2+ sensitization of bronchial smooth muscle contraction concurrent with the airway hyperresponsiveness (AHR), the ACh-induced increases in cytosolic Ca2+ ([Ca2+]) level and contractile response were simultaneously determined by using Fura-2 loaded bronchial smooth muscle. The left main bronchi were isolated from AHR rats which were sensitized and repeatedly challenged with DNP-Ascaris antigen. The tissue ring preparations were incubated in loading solution containing 10 microM Fura-2AM for 3 hr at room temperature. Then the isometrical contraction and [Ca2+]i (F340/F380) were monitored. Although the ACh (10(-3) M)-induced contractile response in AHR group (322 +/- 60 % of 60 mM K+ induced contraction) was significantly greater than that in control animals (173 +/- 15 %, p<0.05), the ACh (10(-3) M)-induced increase in [Ca2+]i was without significant difference between the two groups (128 +/- 15 and 171 +/- 29% of 60 mM K+ -induced increase in [Ca2+]i, respectively). These findings suggest that an augmentation of ACh-induced Ca2+ sensitization may occur in bronchial smooth muscle of the rats with antigen-induced AHR.

Acetylcholine↗
PubMed1998

Lysophosphatidylcholine potentiates vascular contractile responses by enhancing vasoconstrictor-induced increase in cytosolic free Ca2+ in rat aorta.

We investigated the effects of palmitoyl-L-alpha-lysophosphatidylcholine on the contractile responses of the endothelium-denuded rat aorta to high K+, noradrenaline, UK14,304 (5-bromo-6-[2-imidazolin-2-ylamino]-quinoxaline) (a selective alpha2 adrenoceptor agonist) and phorbol 12-myristate 13-acetate (PMA). Lysophosphatidylcholine at concentrations from 10(-6) M to 10(-4) M did not contract aortic strips. However, lysophosphatidylcholine strongly potentiated the UK14,304-induced contraction. High K+ - and PMA-induced contractions were also potentiated. In contrast, the noradrenaline-induced contraction was only slightly potentiated by 10(-5) M lysophosphatidylcholine. In fura PE-3-loaded aortic strips, lysophosphatidylcholine (10(-5) M) markedly augmented the increase in both cytosolic free Ca2+ ([Ca2+]i) and contractile tension induced by UK14,304, high K+ and PMA. Nicardipine (10(-7) M) and 10(-6) M Ro-31-8220 (¿1-[3-(amidinothio)propyl-1H-indoyl-3-yl]-3-(1-methyl-1H-++ +indoyl-3-yl)-maleimide-methane sulfate) strongly inhibited the increase in [Ca2+]i and contractile tension induced by UK14,304 and in the presence of these inhibitors, the enhancing effects of lysophosphatidylcholine were attenuated. However, the enhancing effect on high K+ -induced contraction was not affected by Ro-31-8220. These results suggest that lysophosphatidylcholine may cause an augmentation of the increase in [Ca2+]i induced by UK14,304 which response is depend on protein kinase C activation and in this way potentiate contractile responses in the rat aorta. Protein kinase C independent mechanisms may also be involved in the enhancing effect of lysophosphatidylcholine on smooth muscle contraction.

Animals↗
PubMed1998

Enhanced degradation of polychlorinated biphenyls by directed evolution of biphenyl dioxygenase.

Biphenyl dioxygenases (BP Dox) from different organisms, which are involved in the initial oxygenation and subsequent degradation of polychlorinated biphenyls (PCB), are similar in structure but have different functions. The large subunit of BP Dox, encoded by the bphA1 gene, is crucial for substrate selectivity. Using the process of DNA shuffling, we randomly recombined the bphA1 genes of Pseudomonas pseudoalcaligenes KF707 and Burkholderia cepacia LB400 and selected for genes that expressed proteins with altered function. Upon expression in Escherichia coli, some of these evolved genes exhibited enhanced degradation capacity, not only for PCB and related biphenyl compounds, but for single aromatic hydrocarbons such as benzene and toluene, which are poor substrates for the original BP Dox.

Amino Acid Sequence↗
PubMed1998

Propagation of various tooth impacts in the human body.

The purpose of this study was to investigate how far tooth impacts were propagated in the body and whether the propagation would be influenced by posture. The impacts were propagated to all recording sites on the head and neck of the 10 examinees tested. In the recordings on the limbs, even at the most distal site, the number of examinees detecting the vibration was seven out of nine examinees. These results showed that the impacts exerted on the tooth were propagated to distal sites of limbs through the bones and soft tissues and implied that the propagated vibration would influence the whole of the body. On the other hand, as the amplitude of propagated vibration was influenced by posture and recording site, the posture during jaw functioning appears to be important.

Acromion↗
PubMed1998

Treatment of the survivors from the Nagoya air crash.

Six patients were taken to our hospital alive just after the air crash at Nagoya Airport in 1994. On admission, all patients suffered from profound shock which rapidly progressed. Serum albumin and hemoglobin levels, and platelet count decreased on admission or soon after. The four patients who died could not recover from the shock and associated rapid deterioration of neurological signs. However, two patients were successfully treated with massive transfusion of packed red blood cells, fresh frozen plasma, fresh blood, and/or platelet concentrate and survived to discharge. We recommend addition of albumin to the transfusate in such cases.

Accidents, Aviation↗
PubMed1996

GTP-binding protein regulates the contractile response elicited by the phorbol ester (PMA)-induced activation of protein kinase C in the isolated rat aorta.

1. The aim of the present study was to investigate the involvement of GTP-binding protein in the contractile response induced by activation of protein kinase C (PKC) in isolated rat aorta. The rats were treated with islet-activating protein (IAP) for 4 days prior to the experiments. 2. In the aorta from control rats, phorbol 12-myristate 13-acetate (PMA) produced biphasic contractions; twitch contraction superimposed on the slowly developing contraction. The twitch contraction was abolished by the removal of external Ca2+ or by treatment with nicardipine. In the aorta pretreated with IAP, PMA produced only a slowly developing contraction, and no twitch contraction was induced. 3. The application of Ca2+ to aortic strips in a Ca(2+)-free solution, that had been treated with 10(-6) M PMA caused concentration-dependent contraction, and the contraction was completely inhibited by IAP. 4. Pretreatment with IAP inhibited Ca(2+)-induced contraction of the aorta in Ca(2+)-free medium in the presence of 10(-6) M clonidine, but did not affect the Ca(2+)-induced contraction in the medium treated with 10(-6) M phenylephrine and 10(-7) M nicardipine. 5. These results suggest that the activation of PKC by PMA produces biphasic contractions in the rat aorta. The twitch contraction may be induced by the activation of voltage-dependent Ca(2+)-channels and the activation may be regulated by IAP-sensitive GTP-binding protein.

Animals↗
PubMed1995

Relationship between contractile responses and cytosolic free calcium levels in response to phorbol ester (PMA) in isolated rat aorta.

We examined the relationship between phorbol ester (PMA)-induced contractile response and cytosolic free calcium level in the rat aorta. PMA (10(-6)M) produced biphasic contraction, i.e., sustained contraction followed by a phasic response superimposed on the sustained contraction. Increase in [Ca2+]i was accompanied by a phasic but not sustained contraction. These results suggest that PMA-induced phasic contraction is dependent on Ca2+ influx but sustained contraction may be due to an increase in Ca2+ sensitivity of contractile protein.

Animals↗
PubMed1993

Phorbol ester (PMA)-induced biphasic contraction of the rat aorta and effects of sodium nitroprusside and forskolin on the contraction.

Effects of sodium nitroprusside (SNP) and forskolin on the contractile responses of aortic strips to phorbol 12-myristate 13-acetate (PMA) were investigated in the present study. PMA produced biphasic contraction in the rat aorta, i.e. sustained, slowly developing contraction followed by phasic contraction superimposed on the sustained contraction. Both sustained contraction and phasic response were completely abolished by treatment with staurosporine. Phasic contraction was completely inhibited by nicardipine or removal of external Ca2+, whereas sustained contraction was not affected by nicardipine. Both SNP and forskolin inhibited sustained contraction. Ca(2+)-induced contraction of the aorta which had been treated with PMA in Ca(2+)-free medium was completely inhibited by nicardipine and was partially inhibited by forskolin, but SNP had no effect on the Ca(2+)-contracture. These results suggest that 1) PMA contacts the rat aorta through stimulation of protein kinase C and activation of voltage-dependent Ca2+ channels; 2) there may be great differences in the effects of cyclic GMP and cyclic AMP on the protein kinase C-induced sustained and phasic contractions.

Adenylyl Cyclases↗
PubMed1993

Phorbol ester (PMA) activates voltage-dependent Ca(2+)-channels in helical but not ring preparation of the rat aorta.

Effects of phorbol 12-myristate 13-acetate (PMA) on the helical and ring preparations from rat thoracic aorta was investigated in the present study. In helical strips, PMA produced biphasic contraction, i.e., sustained contraction followed by a phasic response superimposed on the sustained contraction. The phasic contraction was completely inhibited by removal of external Ca2+, whereas sustained contraction was not affected by the treatment. In the ring preparation, PMA produced only sustained contraction, whereas phasic contraction was not induced. On the other hand, in the ring preparation which had been treated with 15 mM K+, PMA was able to produce phasic contraction. Contractile response of the aorta to norepinephrine (NE) or clonidine in the ring preparations was significantly weaker than that in the helical strips. In the presence of nifedipine, however, these different sensitivity to NE between ring and helical preparations was not shown. These results suggest that an activation of C-kinase by PMA is able to stimulate voltage-dependent Ca(2+)-channels in the helical strips but not ring preparation of the aorta. An increased contractile response of the aorta to agonists in helical strips may be responsible for an increased activities of voltage-dependent Ca(2+)-channels.

Animals↗
PubMed1992

[Laparoscopic nephrectomy. Preliminary report].

Laparoscopic surgery has been widely performed for removing the gallbladder and the pelvic lymph-nodes in recent years. We have applied laparoscopy technique to nephrectomy and here we describe our procedures and the clinical results. The patient is placed in the supine position under general anesthesia. After a 4 liter CO2 pneumoperitoneum is induced, five trocars are inserted into the abdominal cavity through the ipsilateral abdominal wall. The patient is then turned to the lateral position to displace the bowel medially. The ipsilateral colon is reflected medially after incision of the parietal peritoneum was made along the line of Todt to expose the retroperitoneum. The ureter was identified and dissected. It was secured with 4 clips (2 clips on the renal side and 2 on the distal side) and then cut with scissors. The renal vein and artery were then dissected and separately ligated with clips as described above. These vessels were also cut. The upper pole of the kidney was dissected out and the adrenal gland was left in place. The kidney thus became completely free within the abdomen. It was then grasped by the forceps through a 10 mm sheath positioned below the umbilicus. After incising the abdominal wall, the kidney was removed from the abdominal cavity with the grasping forceps and the sheath. By this procedure right nephrectomy was completely performed in a 56-year-old female patient and left nephrectomy in a 56-year-old male patient. The underlying disease was recurrent pyelonephritis secondary to renal calculi in both cases. The operative times were 221 min and 346 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1992

[A case report of aneurysm in the root of splenic artery of the spleno-mesenteric type treated with reanastomosis].

A 76-year-old woman with lumbo-abdominal pain as a chief complaint went through a series of examinations including ultrasonography, CT, and angiography, the final diagnosis being aneurysm of the splenic artery congenitally arising from the superior mesenteric artery (SMA). Since the SMA had to be clamped during the excision of the aneurysm, a biballoon intraluminal shunting was utilized to avoid the visceral ischemia. The splenic artery distal to the aneurysm then underwent end-to-side anastomosis to the SMA. This shunting procedure was considered convenient and applicable to other similar situations in the vascular surgery.

Aged↗
PubMed1985

A temperate phage of Streptomyces azureus.

A new phage, SAt1, was isolated from soil on Streptomyces azureus ATCC 14921. This phage was able to lysogenize S. azureus. The percentage of lysogenic responses was ca. 10%. Electron microscopic observation showed that this phage belonged to group B of Bradley's morphological classification. The molecular mass of SAt1 DNA was ca. 24 megadaltons. The guanine-plus-cytosine content and the density of SAt1 DNA were ca. 71% and 1.724 g/cm3, respectively. A cleavage map of SAt1 DNA was constructed with restriction endonucleases BanIII, BglII, HindIII, and XbaI. Furthermore, some other characteristics of this phage were investigated.

Bacteriophages↗