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Biomedical subjects

K Masada

Publications and source records attributed to K Masada.

At least 19 recordsLinked to original sources
PubMed1999

Effects of adrenomedullin and PAMP on adrenal catecholamine release in dogs.

We examined the effects of proadrenomedullin-derived peptides on the release of adrenal catecholamines in response to cholinergic stimuli in pentobarbital sodium-anesthetized dogs. Drugs were administered into the adrenal gland through the phrenicoabdominal artery. Splanchnic nerve stimulation (1, 2, and 3 Hz) and ACh injection (0.75, 1.5, and 3 microgram) produced frequency- or dose-dependent increases in adrenal catecholamine output. These responses were unaffected by infusion of adrenomedullin (1, 3, and 10 ng. kg-1. min-1) or its selective antagonist adrenomedullin-(22-52) (5, 15, and 50 ng. kg-1. min-1). Proadrenomedullin NH2-terminal 20 peptide (PAMP; 5, 15, and 50 ng. kg-1. min-1) suppressed both the splanchnic nerve stimulation- and ACh-induced increases in catecholamine output in a dose-dependent manner. PAMP also suppressed the catecholamine release responses to the nicotinic agonist 1, 1-dimethyl-4-phenylpiperazinium (0.5, 1, and 2 microgram) and to muscarine (0.5, 1, and 2 microgram), although the muscarine-induced response was relatively resistant to PAMP. These results suggest that PAMP, but not adrenomedullin, can act as an inhibitory regulator of adrenal catecholamine release in vivo.

Acetylcholine↗
PubMed1999

Role of ET(B) receptors and nitric oxide in adrenal catecholamine secretion in anesthetized dogs.

We examined the effects of sarafotoxin 6c (S6c), an endothelin-B (ET(B)) receptor agonist, on adrenal catecholamine secretion in response to cholinergic stimuli in pentobarbital sodium-anesthetized dogs. Drugs were administered intra-arterially into the adrenal gland through the phrenicoabdominal artery. Infusion of S6c attenuated increases in adrenal catecholamine output induced by splanchnic nerve stimulation. The inhibitory effect of S6c on the catecholamine secretion response was suppressed with a selective ET(B) receptor antagonist N-cis 2, 6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D-1-methoxycarbonyl tryptophanyl-D-norleucine (BQ-788), a nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine methyl ester, and a neuronal NOS inhibitor 7-nitroindazole monosodium salt (7-NINA). Similar results were obtained with the catecholamine secretion response induced by injection of ACh. 7-NINA alone did not affect these catecholamine secretion responses. These results suggest that ET(B) receptors play an inhibitory role in adrenal catecholamine secretion by activating neuronal NOS, whereas neuronal NOS is unlikely to be involved in regulation of adrenal catecholamine secretion in the absence of simultaneous ET(B) receptor stimulation.

Acetylcholine↗
PubMed1998

Role of K+ channels in adrenal catecholamine secretion in anesthetized dogs.

We examined the role of K+ channels in the secretion of adrenal catecholamine (CA) in response to splanchnic nerve stimulation (SNS), acetylcholine (ACh), 1,1-dimethyl-4-phenyl-piperazinium (DMPP), and muscarine in anesthetized dogs. K+ channel blockers and the cholinergic agonists were infused and injected, respectively, into the adrenal gland. The voltage-dependent K+ channel (KA type) blocker mast cell degranulating (MCD) peptide infusion (10-100 ng/min) enhanced increases in CA output induced by SNS (1-3 Hz), but it did not affect increases in CA output induced by ACh (0.75-3 micrograms), DMPP (0.1-0.4 microgram), or muscarine (0.5-2 micrograms). The small-conductance Ca(2+)-activated K+ (SKCa) channel blocker scyllatoxin infusion (10-100 ng/min) enhanced the ACh-, DMPP-, and muscarine-induced increases in CA output, but it did not affect the SNS-induced increases in CA output. These results suggest that KA channels may play an inhibitory role in the regulation of adrenal CA secretion in response to SNS and that SKCa channels may play the same role in the secretion in response to exogenously applied cholinergic agonists.

Acetylcholine↗
PubMed1997

Osteosynthesis for the treatment of non-union of the lateral humeral condyle in children.

We reviewed the results of osteosynthesis for the treatment of an established non-union of the lateral humeral condyle in sixteen children whose average age was nine years (range, four to thirteen years) at the time of the operation. The average interval between the injury and the operation was five years (range, five months to ten years). The presenting symptoms were pain in the elbow in seven patients, apprehension in nine, a cubitus valgus deformity in six, limitation of motion in three, and dysfunction of the ulnar nerve in four. The average duration of follow-up was eleven years (range, four to thirty-two years). Osseous union was achieved after the initial operation in thirteen patients. Of the three patients who had a persistent non-union, two had a second operation and the third, who was asymptomatic, refused additional operative intervention. The result was rated excellent in eight patients, good in seven, and poor in one, with use of a modification of the functional rating index of Broberg and Morrey. The patient who had a poor result had evidence of avascular necrosis of the fragment.

Adolescent↗
PubMed1993

Isolated fracture-dislocation of the sacrum: case report.

An unusual case of isolated fracture-dislocation of the sacrum is reported. A 19-year-old woman had a fracture-dislocation of S-1-2 combined with two longitudinal fractures of the sacrum, but no other pelvic fractures were identified. The possible mechanisms of fracture-dislocation of the sacrum are discussed. The fracture site was identified accurately on a CT scan. Pain relief was obtained by application of an external fixator. A mild neurologic deficit in the S-1 root distribution disappeared uneventfully.

Adult↗
PubMed1992

Perceptions of psychological researchers and clinicians: a questionnaire based on empirical data and theory.

Clinical and research psychologists continue to be regarded stereotypically even by 187 students currently anticipating careers in psychology and closely related fields. This article gives data for 10 issues on which clinicians and researchers are perceived to differ. Specifically, a 10-item questionnaire is described which allows such stereotypes to be further explored or explained.

Adult↗
PubMed1992

Lymphangioma of the upper extremity.

Lymphangioma of the upper extremity is rare; its treatment is unstandardized. We reviewed five female and one male patient with cavernous lymphangioma of the hand and forearm. Each of them underwent at least one surgical procedure. Five patients had satisfactory results with cosmesis and hand function. Satisfactory results are expected in those treated initially in early childhood, as most lymphangiomas tend to increase gradually in size and infiltrate previously uninvolved normal tissues.

Arm↗
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

Constrained total elbow arthroplasty.

In 1972, the senior author designed a condylar-sparing constrained hinge elbow prosthesis with a high-density polyethylene bushing. The condylar-sparing design allows both intercondylar and intramedullary fixation of the humeral component with methylmethacrylate cement. Reattachment of the muscles and collateral ligaments to the preserved condyles provides further stability. The clinical experience spans more than 16 years in 42 elbows with a relatively low loosening rate of 7%. The implant was removed and not replaced in three elbows: one for late infection, one for posttraumatic comminuted fracture of the distal humerus, and one for loosening of a humeral component. A series of 27 patients (31 elbows) with 24-204 months of follow-up study (average, 77 months) had excellent pain relief and an average range of motion of 129 degrees flexion, -44 degrees extension, 69 degrees pronation, and 61 degrees supination.

Bone Cements↗
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

Effect of early synovectomy on the course of rheumatoid arthritis.

Ninety-one patients with rheumatoid arthritis were retrospectively assigned to 3 subsets according to the number of joints with erosion (NJE). The subsets were least erosive (LES); more erosive (MES); most erosive involving multilating disease (MUD). In the early stages of disease the subsets were distinct (p less than 0.001) regarding mean values of annual reduction of carpal height (delta CHR) and serum Clq levels. Patient assessment (radiographic and clinical) continued to deteriorate in the MES and MUD subsets over the 1-5 year interval after synovectomy. Apparent stabilization of knee disease in the LES subset may be a feature of this subset rather than a result of synovectomy. Although synovectomy may offer short term symptomatic relief, we found no evidence that it retards the bony destruction or the disease process.

Adult↗
PubMed1991

Collateral ligament reconstruction of the metacarpophalangeal and proximal interphalangeal joints using porous dacron tendon.

We are encouraged by the favorable preliminary results of ligamentous reconstruction using the porous Dacron tendon. It provides a stable construct in cases where there is insufficient local autogenous tissue, and obviates the need for a tendon graft. Early active range of motion is permitted. Current investigation for additional applications for the use of the porous Dacron tendon include volar plate reconstruction following disruption, capsuloligamentous reconstruction of the trapezial metacarpal joint (with trapezium implant arthroplasty as well as for isolated disruption of the volar oblique ligament), intercarpal ligament repair or augmentation, and distal radioulnar joint stabilization.

Arthritis↗
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

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

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↗