Biomedical subjects

H Kawabata

Publications and source records attributed to H Kawabata.

At least 19 recordsLinked to original sources

PubMed1992

Enhancing effect of heterocyclic amines and beta-carbolines on UV or chemically induced mutagenesis in E. coli.

Most heterocyclic amines and beta-carbolines--harman, norharman, harmine, harmaline--enhanced UVC (254 nm) induced mutagenesis without microsomal activation in E. coli B/r WP2. 3-Amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) was most effective and increased UVAB (295-400 nm) induced mutations as well as UVC induced ones. Trp-P-1 enhanced the frequencies of mutations induced by not only UV but also 4-nitroquinoline-1-oxide (4NQO) or 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF2), while it showed little effect on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or gamma-ray induced mutagenesis. Trp-P-1 decreased the survival of UVC irradiated cells of CM571recA. However, these effects of Trp-P-1 on UVC induced mutagenesis and lethality were not observed in WP2suvrA which is excision repair deficient. The alkaline sucrose gradient sedimentation analysis demonstrated that Trp-P-1 blocked the incision step in DNA excision repair. Further, pretreatment with Trp-P-1 before UVC irradiation showed no effect on UVC induced mutagenesis. Similar effects were also seen in the case of harman or norharman. These results suggest that heterocyclic amines and beta-carbolines inhibit DNA excision repair directly or indirectly, thus enhancing UV or chemically induced mutagenesis.

Amines↗

PubMed1992

Experimental Borrelia burgdorferi infection of outbred mice.

Infectivity of Borrelia burgdorferi strain 297 in normal outbred ddY mice was examined. Strain 297 was inoculated intraperitoneally in 3-week-old outbred ddY mice. B. burgdorferi was routinely cultured from the heart and urinary bladder 5 to 84 days postinoculation. The combined isolation rate from both heart and urinary bladder was significantly higher than the rate from spleen, kidney, liver, urine, and blood samples. Three- and 10-week-old mice were infected with inocula of 10(4) and 10(5) or more, respectively. Passive transfer of undiluted and 10-fold-diluted anti-297 rabbit serum and active immunization of 50 to 100 micrograms of lyophilized whole cells completely protected mice from infection with B. burgdorferi. These results suggest that the outbred mouse is a convenient model for experimental infection with B. burgdorferi.

Animals↗

PubMed1992

[The significance of soluble IL-2 receptors in rheumatoid arthritis with interstitial pneumonia].

Interstitial pneumonia is well known as one of the complications of rheumatoid arthritis (RA). While interleukin-2 (IL-2) regulates the immune response through IL-2 receptor (IL-2R), the exact role of the soluble form of IL-2R (sIL-2R), recognized as a part of the alpha chain or IL-2R, is still obscure. So, the immunological significance of sIL-2R in serum and in bronchoalveolar lavage fluid (BALF) of those of RA patients with or without interstitial pneumonia was studied. The sIL-2R was measured with an ELISA kit (T-Cell Science Ltd). The levels of sIL-2R in the sera of RA patients without interstitial pneumonia were significantly higher than those of normal controls. Furthermore, the levels of sIL-2R showed a statistically significant correlation with ESR and Lansbary's index. The levels of sIL-2R of RA patients with interstitial pneumonia were higher than in those without interstitial pneumonia although the evaluation of class and stage of arthritis in those RA patients with or without interstitial pneumonia revealed no significant difference. A high sIL-2R/albumin ratio in BALF of RA patients with interstitial pneumonia was shown in comparison with those of normal control. These data indicate that the estimation of sIL-2R in RA patients could be useful in estimating the disease activity and that high levels of sIL-2R reflect the active immune response in the lungs of RA patients with interstitial pneumonia.

Arthritis, Rheumatoid↗

PubMed1991

Experience with calcium antagonists nitrendipine, diltiazem, and verapamil and beta 2-agonist salbutamol in salvaging ischemic skin flaps in rabbits.

This study investigated the efficacy of selected agents in the salvage of experimental skin flaps in rabbits after 21 hours of 25 degrees C ischemia. Calcium channel antagonists nitrendipine, diltiazem, and verapamil increased ischemic skin flap survival in rabbits from 33.3% for buffered saline infused controls to 71.4% (P less than 0.05), 71.4% (P less than 0.05), and 50.0% (not significant) respectively. The beta 2-adrenoceptor agonist salbutamol produced an increase in survival to 64.3%, which narrowly missed statistical significance. All four test agents invoked a vasodilatory response (greatest for nitrendipine, diltiazem, and salbutamol), a slight fall in blood pressure, and a small increase in heart rate. It is concluded that the vasodilatory response in the microcirculation of the ischemic flap helped to minimize the risk of occlusion due to thrombosis or cell sludging during reperfusion, thus leading to improved flap survival.

Albuterol↗

PubMed1991

Prostacyclin and prostanoid modifiers aid ischemic skin flap survival.

Prostacyclin, the stable prostacyclin analogue carbacyclin, the thromboxane synthetase inhibitor UK-38,485, and the phosphodiesterase inhibitor dipyridamole were tested on rabbit epigastric free flaps for their ability to improve flap survival after a period of ischemia. Control flaps infused with a balanced salt solution had a 39.9% survival, whereas prostacyclin, carbacyclin, and dipyridamole significantly increased flap survival to 68.4% (P less than 0.05), 66.4% (P less than 0.05), and 66.9% (P less than 0.05), respectively. UK-38,485 improved survival slightly to 47.6% although not significantly. The improved flap survival correlated with the vasodilatory properties of the three successful agents whereas the antithrombotic properties of UK-38,485 were not sufficient, on their own, to increase flap survival.

Animals↗

PubMed1991

Rupture of the flexor pollicis longus in von Recklinghausen's disease.

An unusual cause of inability to flex the interphalangeal joint of the thumb in a patient with von Recklinghausen's disease is reported. A tumor in the cubital fossa and the basic characteristics of this disease led to a preoperative misdiagnosis of anterior interosseous nerve paralysis. However, surgical exploration and histological examination showed that the correct diagnosis was rupture of the flexor pollicis longus tendon caused by intratendinous proliferation of a neurofibroma. This is the first report in the English-language literature of a flexor tendon rupture caused by intratendinous tumor proliferation.

Adult↗

PubMed1991

Topical use of Xylocaine for relieving vasospasm: effect of concentration.

The spasmolytic and antispasmodic effects of Xylocaine in different concentrations were studied. Twenty-five Wistar rats were divided into five groups according to the concentrations of Xylocaine used (2 percent, 4 percent, 10 percent, 20 percent, and 40 percent). The diameters of rat femoral arteries were measured with vernier calipers under the microscope. Effects were evaluated by the percentage of the test arterial diameter compared with that of the control contralateral artery. Vasospasm of both femoral arteries was produced by administration of the fresh blood of other rats. After immersion in the blood for 10 min. Xylocaine was administered into the right femoral artery for 10 min to examine its spasmolytic effect. The effects of the concentrations shown by the percent diameter were 106 percent, 108 percent, 107 percent, 111 percent, and 106 percent, respectively. There was no significant statistical difference between each agent and its control. Thirty minutes after removal of the agent, 2 percent Xylocaine failed to maintain its spasmolytic effect, while 4 percent, 10 percent, 20 percent, and 40 percent Xylocaine did maintain it. Next, blood was again administered after vessel immersion in the agent to examine its antispasmodic effect. The effects of the concentrations were 100 percent, 114 percent, 124 percent, 152 percent, and 146 percent. There were statistically significant differences, except in the case of 2 percent Xylocaine. Twenty-percent Xylocaine demonstrated a superior antispasmodic effect. The duration of the spasmolytic effect and the antispasmodic effect were concentration-dependent, up to approximately 20 percent.

Animals↗

PubMed1991

Antigenic and genomic comparisons of some feline parvovirus subspecies strains.

Fourteen feline parvovirus (FPV) strains isolated from cats, mink and dogs were comparatively examined on their antigenic and genetic diversities by using monoclonal antibodies against feline panleukopenia virus (FPLV) and restriction enzyme analysis of viral DNA. Mink enteritis virus (MEV) strains recently isolated in the northeastern area of the People's Republic of China were found to possess more similar antigenic and genetic properties to the antigenic variant virus of canine parvovirus (CPV) ("new" antigenic type CPV), than to FPLV strains and MEV Abashiri strain of Japan. A feline isolate detected in normal cat feces was considered to be rather CPV because of its antigenic and genetic characteristics. An early isolate of "new" antigenic type CPV strains showed a similar cleavage pattern to those of "old" antigenic type CPV strains when digested with HinfI. The results including some features above-mentioned suggest the presence of antigenic heterogeneities and genomic polymorphisms among FPV subspecies viruses.

Animals↗

PubMed1990

The salvage of rabbit ischaemic epigastric free flaps using the vasodilator calcitonin gene-related peptide.

The rabbit epigastric free flap, subjected to 21 hours of warm (25 degrees C) ischaemia, was used as an experimental model to test the ability of two endothelium-dependent vasodilators, calcitonin gene-related peptide (CGRP) and carbamyl beta-methylcholine chloride (MCh, bethanechol chloride, the stable acetylcholine analogue) to improve flap viability. After the period of ischaemia, flaps were infused intra-arterially with either Hanks balanced salt solution (controls), CGRP or MCh for 30 minutes, and received additional intravenous boluses of these drugs at 2 and 32 minutes after revascularisation. The area of flap surviving improved significantly (p less than 0.025) from 39.9% (n = 18) for controls to 70.2% (n = 14) for CGRP treatment at 2 micrograms/kg, but was unchanged at 47.1% (n = 14) for MCh treatment at 50 micrograms/kg. Both CGRP and MCh significantly increased blood flow (p less than 0.05) resulting in 34% lower peripheral resistances compared with controls. These results suggest that CGRP has considerable clinical potential for the salvage of ischaemic flaps. CGRP must have several, as yet undefined, beneficial effects on the ischaemic tissue, since MCh invoked a vasodilatory response but failed to salvage ischaemic flaps.

Abdominal Muscles↗

PubMed1990

DNA strand scission by neocarzinostatin: molecular recognition process responsible for site-specificity.

A series of hexanucleotides possessing A-T, G-C, inosine (I)-C and 2-aminoadenine (ANH2)-T base pairs at 5'-side of the target thymine were prepared and their selectivity for C-5' and C4' oxidation in the NCS-mediated degradation was investigated. Quantitative product analysis indicated that preferential C5' oxidation of deoxyribose moiety of the target T occurs at -5'-AT- and 5'-IT- sites, whereas C5' and C4' oxidation occurs competitively at T of -5'-GT- and -5'-ANH2T- sites. Based on the experimental results, an intercalation model that permits competitive hydrogen abstraction from C5' and C4' of deoxyribose moiety has been proposed.

Base Sequence↗

PubMed1990

Osteosynthesis for old, established non-union of the lateral condyle of the humerus.

In thirty elbows that had an established non-union of a fracture of the lateral humeral condyle that had occurred more than five years before, treatment consisted of one of three operations: anterior transposition of the ulnar nerve (nine patients), corrective osteotomy of the humerus and anterior transposition of the ulnar nerve (four patients), or osteosynthesis of the non-union combined with neurolysis and anterior transposition of the ulnar nerve, with or without corrective osteotomy of the humerus (seventeen patients). Of the thirty patients, fifteen had been apprehensive when using the elbow, due to lateral instability, or had had pain in the elbow. In thirteen of these fifteen patients, the non-union was treated by osteosynthesis. Afterward, the pain and apprehension disappeared, but the range of motion of the elbow decreased in all but three patients. Three patients had clicking between the humerus and radius, and the bone failed to unite in three others. Osteosynthesis is indicated for the treatment of non-union of the lateral humeral condyle only if the patient has serious pain in the elbow or apprehension when using the elbow, due to lateral instability.

Adolescent↗

PubMed1990

[Changes in myocardial energy charge following cardiac arrest and subsequent resuscitation].

Cardiac resuscitation becomes more difficult as time of arrest is prolonged. This study was designed to investigate changes in energy charge (EC) during cardiac arrest and subsequent resuscitation periods. The experiment was divided into 2 parts. In the first part, 36 rats were divided into 6 groups. Control rats were anesthetized only with pentobarbital and the heart was extirpated. In other rats, an acute exsanguination was carried out until mean arterial pressure (MAP) fell to 0, and then the rats were divided into 5 groups according to the time of extirpation following the cardiac arrest: 1, 5, 10, 15 and 20 minutes, respectively. The extirpated hearts were rapidly frozen with liquid nitrogen. ATP, ADP and AMP were enzymatically measured and EC was calculated. ECG was monitored to ascertain complete electrical arrest. Disappearance of ECG activity was observed about 9 minutes after MAP reaching zero. In the second part; 36 rats were also divided into 6 groups. After the same manipulation as in the first part, the extirpated heart was perfused for 30 minutes using Langendorff method and both cardiac function (LVP, LV dp/dt and HR) and EC were investigated. Total adenine nucleotide (TAN) was already diminished at 1 minute and decreased progressively. On the contrary, EC was well maintained around control level until ECG activity disappeared completely, and an abrupt decrease in EC occurred after electrical arrest. When the heart was perfused about 30 minutes, EC recovered almost to the control level in the groups in which perfusion was started within 10 minutes, but its recovery was incomplete in the groups in which perfusion was begun after 10 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Revision of residual deformities after operations for duplication of the thumb.

We treated thirty-six patients (thirty-eight thumbs) who had residual deformity after ablation of a duplicated thumb. The deformities were classified into three groups: interphalangeal (eight thumbs), metacarpophalangeal (sixteen thumbs), and zigzag (fourteen thumbs). The indication for operation was primarily cosmetic; only eight patients had a functional disability, and that was mild. At the most recent follow-up, the results were rated good except for three fair results in the group that had an interphalangeal deformity, two fair results in the group that had a metacarpophalangeal deformity, and two poor and seven fair results in the group that had a zigzag deformity.

Adult↗

PubMed1989

Factors involved in salvaging ischaemic rabbit skin flaps: ATP and free radicals but not thromboxane.

Rabbit epigastric free flaps were subjected to ischaemia at 25 degrees C for 24 hours. At the time of revascularisation the flaps were infused intra-arterially with one of the following: Hanks balanced salt solution (control), the high energy phosphates PEP/ATP, the thromboxane synthetase inhibitor dazoxiben hydrochloride, the free radical scavenger SOD and a combination of all these agents (treated groups). Control ischaemic flap survival at post-ischaemia day 7 was 23.5%, while the other treatments resulted in improved flap survival of 43.5% (p less than 0.025), 23.5% (not significant), 38.6% (p less than 0.05) and 35.7% (p less than 0.05) respectively. None of these agents improved post-ischaemic blood flow significantly. These results would support the use of PEP/ATP or SOD in the clinical treatment of failing ischaemic skin flaps but do not support the use of dazoxiben hydrochloride.

Adenosine Triphosphate↗

PubMed1989

Computer-aided analysis of Z-plasties.

Various Z-plasties were evaluated with a mathematical analytical method called the finite-element method. The lengthening and shortening effects on the skin proved to depend on the tip angle. Serial Z-plasties diminished the stress concentration after pairs of flaps had been transposed. Subdivided Z-plasties proved to be the most effective for lengthening. The finite-element method provided a good simulation of Z-plasties on a skin with complex properties. The lengthening and shortening effects on anisotropic skin were influenced not by the degree but by the direction of the anisotropy, whereas the total force required for transposing the two flaps was vice versa. The finite-element method was found to be useful for finding analytical solutions for biomechanical skin problems.

Animals↗

PubMed1989

Operations for forearm deformity caused by multiple osteochondromas.

We reviewed 36 cases of forearm deformity caused by multiple osteochondromas in 30 patients and classified them into three types: Type I showed a combination of ulnar shortening and bowing of the radius secondary to osteochondromas of the distal ulna (22 forearms). Type II showed dislocation of the radial head, either with osteochondromas of the proximal radius (Type IIa, two forearms) or secondary to more distal involvement (Type IIb, five forearms). Type III had relative radial shortening due to osteochrondromas at the distal radius (seven forearms). Operations were performed on 16 forearms in 13 patients, with 92% of satisfactory results. For Type I deformity, excision of osteochondromas, immediate ulnar lengthening and corrective osteotomy of the radius are recommended. For Type IIa, excision of the radial head is necessary, and for Type IIb, we advise gradual lengthening of the ulna using an external fixator. Excision of osteochondromas alone gave good results in Type III deformity. Our classification gives a reliable indication of the prognosis and is a guide to the choice of surgical treatment.

Adolescent↗

PubMed1989

Stretching of the brachial plexus in rabbits.

The brachial plexus of rabbits was stretched until mechanical failure. The level and site of rupture varied according to the direction of the stretching force. Upward and lateral traction of the forelimbs caused spinal nerve-root avulsions combined with nerve-trunk ruptures distal to the dorsal root ganglions. In such tractions the C5 nerves consistently exhibited postganglionic nerve-trunk rupture. The C6, C7, and C8 nerves had root avulsions. The T1 nerve was avulsed from the spinal cord in 7 cases out of 10; the other 3 cases had postganglionic nerve-trunk rupture. Downward traction of the forelimbs caused nerve avulsions from the scapulohumeral muscles innervated by the terminal branches of the brachial plexus and peripheral nerve ruptures in the course of the arm. The force producing trunk rupture of the C6 nerve was twice as great as that for root avulsion. The required stain was similar for nerve trunk rupture and root avulsion.

Animals↗

PubMed1989

DNA strand scission by antitumor antibiotics. Detection of C-4'-hydroxylated abasic sites in DNA.

Detection of C-4'-hydroxylated abasic site in calf thymus DNA was investigated. Upon heating with neutral hydrazine (90 degrees C, 5 min) C-4'-hydroxylated abasic site formed by photo-excited Co(III)bleomycin was converted to the fragments having 3'-phosphoro-3''-pyridazinylmethylate as illustrated on Scheme 1. Subsequent enzymatic digestion of the reaction mixture provided four kinds of pyridazine mononucleotides (1, 2, 3, and 4). The fact that the amount of free bases released from calf thymus DNA corresponded well to the amount of pyridazines indicates this reaction can be used for detection of C-4'-hydroxylated abasic site in DNA. By this assay, we first identified the formation of C-4'-hydroxy abasic sites in calf thymus DNA by neocarzinostatin.

Antibiotics, Antineoplastic↗