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Biomedical subjects

N Isshiki

Publications and source records attributed to N Isshiki.

At least 37 records · Page 2Linked to original sources
PubMed1994

Involvement of lipid peroxidation in necrosis of skin flaps and its suppression by ellagic acid.

To evaluate the pathogenesis of lipid peroxidation in skin-flap necrosis and to select a novel herbal antioxidant to suppress lipid peroxidation and salvage the flaps, in vitro and in vivo experiments were instituted. In vitro studies revealed (1) the potentiality of the cutaneous microsomal system (vesicular fragment of endoplasmic reticulum) to generate oxyradicals by FeCl3 (oxidative agent), since NADPH-dependent lipid peroxidation was elevated time-dependently, (2) suppression of microsomal lipid peroxidation by herbal antioxidants (dose- and time-dependently), further supporting the theory of oxyradical-induced lipid peroxidation in the skin, and (3) that ellagic acid showed the strongest response, with curcumin, chlorogenic acid, and alpha-tocopherol (tocopherol) being moderate, and ferulic acid and gallic acid remaining weakest. Thus ellagic acid, curcumin, chlorogenic acid, and tocopherol at doses of 10, 60, 80 and 100 microM (twice I50, the dose which could inhibit lipid peroxidation by 50 percent) were chosen for in vivo assessments, respectively. In vivo studies were performed using rat back skin random flaps (70 x 15 mm and based anteriorly) and circular island flaps (20 mm in diameter and raised on superficial epigastric vessels). Control flaps were painted with a Tris-ethanol solution, and test flaps were painted with either ellagic acid, curcumin, chlorogenic acid, or tocopherol (above-mentioned doses per 250 microliters of Tris-ethanol per 300 mm2 of flap surface 1 hour before the operation and once a day for 3 postoperative days). Doses, frequency, and period of drug application were based on in vitro and in vivo pilot experiments. The results were as follows: (1) a direct and time-dependent relation was noticed between lipid peroxide levels and the rate of necrosis in both types of flap; (2) time-dependent elevation of lipid peroxide levels of skin, subcutaneous fat, and exudate of island flaps during ischemia and those of skin and subdermal fat after reperfusion indicated pre- and post-reflow states of lipid peroxidation rather than the original conception of merely reperfusion state; and (3) in good agreement with the results of in vitro experiments, ellagic acid exerted the strongest effect to suppress lipid peroxide levels of skin and to augment the viability of random flaps more than that of island flaps.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

The use of microsurgical planing to treat traumatic tattoos.

A traumatic tattoo results from an abrasion in which dirt, carbon, tar, asphalt, or other particles have become embedded beneath the superficial layer of the dermis. These embedded particles are difficult to remove completely. Under a microscope, rectangular epidermal and upper dermal grids including these pigments are made, and each section of the grid is removed. The microsurgical planing technique has the following advantages: it saves the maximum possible amount of normal skin, and the particles are completely removed. Twenty patients have been treated with this technique and have obtained excellent results.

Accidents, Traffic↗
PubMed1994

Tissue transfer with a distal to proximal arteriovenous anastomosis for venous drainage: microcirculatory analysis on the rabbit ear model.

An experimental study was conducted to find out the survival mechanism of tissue transfers drained by distal to proximal arteriovenous fistulas in 22 rabbit ear chambers using a videorecording system. In the first experiment (n = 12) the rabbit earlobe was cut at the base to eliminate blood and lymphatic flow. The central artery was reanastomosed and an anterior marginal distal to proximal arteriovenous anastomosis was created. In the second experiment (n = 10) the anterior marginal artery was reanastomosed, and a central distal to proximal arteriovenous fistula was created. In the first experiment, constant blood flow was observed postoperatively in arterioles, venules, capillaries and arteriovenous shunts, while in the second experiment, no blood was observed in any vessels. In conclusion, capillary blood circulation was experimentally confirmed in a tissue transfer with distal to proximal arteriovenous anastomosis, and selection of arteries, one for reanastomosis and one for anastomosis to a vein for drainage, seems to be of critical importance for the success of this tissue transfer.

Anastomosis, Surgical↗
PubMed1994

A new skin equivalent: keratinocytes proliferated and differentiated on collagen sponge containing fibroblasts.

Three types of artificial skin containing keratinocytic components were prepared and tested for comparison. Keratinocytes were cultured on the artificial skin dermis (collagen sponge) by the air-liquid interface culture method. In order to create continuous keratinocytic layers on the artificial skin dermis, pores of its uppermost layer were filled beforehand with type I collagen gel, Matrigel, or fibroblasts. A band of keratinocytes consisting of two to six cell layers was formed on collagen gel-coated artificial skin dermis. On Matrigel-coated artificial skin dermis, keratinocytes were piled up into about 20 cell layers, but cell differentiation was incomplete; cornified material was not fully developed, and the proportion of cuboidal cells was very high compared with normal epidermis. Keratinocytes formed continuous layers on the fibroblasts-artificial skin dermis complex without gel coating. Keratinocytes proliferated well and differentiated properly on this matrix, and their histologic appearance was similar to that of normal epidermis. Thus keratinocytes cultured on the fibroblast-artificial skin dermis complex seem to be a good skin equivalent.

Adult↗
PubMed1994

A new treatment for parrot beak deformity of the toe.

Two cases of congenital parrot beak deformity of the toe were treated by pushing back the nail plate, nailbed, matrix, and proximal skin fold in one piece as a flap. The proximal skin portion of this flap was deepithelialized to facilitate this shift, and thus no dog-ear deformity was produced. The distal skin defect of the pulp was covered by a palmar advancement flap. This method does not require augmentation of the fingertip or toetip and is very useful for correcting parrot beak deformities of the toes.

Adolescent↗
PubMed1993

Viability and quantitative dermofluorometry of experimental arterialised and non-arterialised venous flaps.

In an attempt to predict venous flap viability, uptake and excretion of fluorescein dye injected intravenously was followed quantitatively at 10 min intervals on flaps on the surface of rabbit ears, with the use of a fiberoptic dermofluorometer. This instrument is a reliable indicator of circulation in non-arterialised or arterialised venous flaps, as it is in conventional flaps. This work shows that arterialised venous flaps are more reliable and have a larger skin territory than non-arterialised ones. Survival of the arterialised venous flap can be attributed primarily to the blood circulation, while the non-arterialised venous flap relies for its survival on both blood circulation and plasmatic inhibition from the bed as well.

Animals↗
PubMed1993

Re-freeze dried bilayer artificial skin.

A bilayer artificial skin composed of a silicone sheet and a collagen sponge sheet was developed by us in 1986, modifying Yannas and Burke's technique. It was used in experimental animals and clinically, both with success; but the artificial skin was inconvenient for clinical use in terms of disinfection and preservation. In an attempt to reduce the drawbacks, we developed a re-freeze dried artificial skin. Experiments were conducted to examine whether the re-freeze dried material is equivalent to the prototype one. A significant difference between the two was found in tensile tests but not in experimental and clinical effects.

Adult↗
PubMed1993

Facial injuries from falling: age-dependent characteristics.

A retrospective analysis was undertaken of 108 patients with facial injuries from falling who presented at the Plastic Surgery Unit of the Toyo-oka Public Hospital from 1988 to 1990. Facial injuries from falling were common in little children, in those < 6 years of age comprising 45.4% of injuries. Age-dependent characteristic injury sites were found (i.e., in those < 2 years old, the forehead; in small children, the chin; in students, the lip; and in older persons, the cheek); this disparity can be explained by the mechanism of injury. The injury pattern also depended on age, varying activities, and tissue strength. In children of < 6 years of age, small lacerations on the forehead or chin were most common, but even conservative treatment could achieve good results. On the other hand, inadequate suturing by emergency room physicians brought on poor results. In adults, abrasions and traumatic tattoos occurring with late-night inebriation tended to develop some sequelae.

Accidental Falls↗
PubMed1992

Evaluation of a bilayer artificial skin capable of sustained release of an antibiotic.

A bilayer artificial skin, composed of an upper silicone sheet and a lower collagen sponge, has been developed by modifying a technique proposed by Yannas and Burke. We have applied it clinically with success, but infection sometimes occurred in the area where the artificial skin was placed. To use it safely in an infected wound, we developed a new type of artificial skin capable of sustained release of antibiotic. Microspheres of poly-L-lactic acid containing an antibiotic, were installed in the upper silicone sheet. The usefulness of the new type of artificial skin was suggested by in vitro studies.

Biocompatible Materials↗
PubMed1992

Time series analysis of glottal airflow in normal and pathological phonation.

Time series analysis of glottal airflow was carried out on 26 normal controls and 40 patients with voice disorders, using a modification of Isshiki's original technique which uses a hot-wire flowmeter, taking cycle-by-cycle fluctuations into consideration. The mean flow rate and mean AC/DC were shown to have significant differences among normal and patient groups. The standard deviations of AC/DC and AC/DC perturbation were calculated from the AC/DC value of 50 cycles and shown not to vary significantly among the normal and patient groups. The relationship between AC/DC and perceptual impression of voice was also studied among 20 selected patients with breathy voices. Using Spearman's rank correlation coefficient, this relationship was found to have statistical significance (P < .05).

Glottis↗
PubMed1992

Experimental studies on the viscoelasticity of the vocal fold.

Viscoelasticity of the vocal fold was assessed by analyzing the stress-strain relationship under several experimental conditions. The stiffness increased with greater tension of the vocal fold. Marked differences in the mechanical properties were noted between the "body" and the "cover" of the vocal fold, especially when tension was applied. Contraction of the thyroarytenoid muscle tended to make the vocal fold less stiff and more viscous. Dry vocal-fold mucosa was associated with greater stiffness. Submucosal injection of saline solution to simulate edema increased the stiffness and viscosity of the vocal fold.

Animals↗
PubMed1992

Mechanical properties of the vocal fold. Stress-strain studies.

The viscoelasticity of the vocal and ventricular folds was experimentally assessed by analyzing the stress-strain relationships obtained using a newly developed measuring system. The degree of stiffness of the mid-membranous portion of the vocal fold was less than that near the anterior commissure or the vocal process. The ventricular fold was much less stiff and significantly more viscous than the vocal fold. At the membranous portion of the vocal fold, the degree of stiffness was less and that of viscosity greater at 2 mm above and below the free margin than at the free margin itself.

Adult↗
PubMed1991

Salvage of distal flap necrosis by topical superoxide dismutase.

Significance of the reactive oxygen species in distal flap necrosis and the efficacy of superoxide dismutase (SOD) in salvaging necrosis have become indicated in recent studies. To enhance the therapeutic effect of SOD, topical application was designed. Water-soluble ointment containing 1% SOD was prepared, and three experiments were made to study the effect of topical SOD in improving flap survival. Simple application of SOD ointment to the upper surface of the flap had no effect, whereas its application to the under surface or occlusive dressing was effective. These effects were corroborated by assay of tissue SOD activity.

Administration, Topical↗
PubMed1991

Reconstruction of both eyelids following electrical burn.

A case of severe electrical burn of the unilateral upper and lower eyelids is reported, together with the surgical technique of reconstruction. A 25-year-old man suffered an electrical burn on his left eyelids. On admission, his left upper and lower eyelids were subtotally necrotic. Total eyelid reconstruction was performed 2 1/2 months later. A chondromucosal graft taken from the nasal septum was utilized as the deep layer of the upper eyelid, which was covered by sliding down the remaining levator muscle and connective tissues to maintain the blood supply to the composite graft. The outer layer of the upper lid was reconstructed with a free split-thickness skin graft. The lower lid was reconstructed with a local flap lined with a free mucosal graft. This sandwich method using the levator muscle as a core was found useful for reconstructing both the upper and lower eyelids.

Adult↗
PubMed1991

Electrical pacing for dynamic treatment of unilateral vocal cord paralysis. Experiment in long-denervated muscle.

In order to explore the possibility of clinical application of laryngeal pacing as a treatment for unilateral vocal cord paralysis, we examined the reactivity of atrophic muscle to electrical stimulation in dogs whose recurrent laryngeal nerves were damaged by crushing, dissection followed by resuturing, or a 3-cm neurectomy. The threshold level to induce enough vocal cord adduction reached the maximum at 2 weeks after nerve injury, decreased with time, and never surpassed 7 V in each case. On the basis of results of these preliminary probings, laryngeal pacing was conducted on a dog 15 months after resection of the laryngeal nerve. Adduction of the paralyzed vocal cord for synchrony with the intact cord was achieved by 7 V of electrical stimulation of the thyroarytenoid muscle that was triggered by signals from the cricothyroid muscle.

Animals↗
PubMed1991

Surgical treatment of laryngeal web with mucosa graft.

Surgical treatment of laryngeal webbing varies with the extent and site of the web. An extensive one seems to be best treated by laryngofissure and skin or mucosa transplantation. Recent experiences with four cases of thick glottal webbing indicated that a mucosa graft was better for the voice result than a skin graft. For success in the airway and voice results, the salient points in surgery include 1) precise midline thyrotomy, 2) shaping of the vocal cord under fiberoptic control, and 3) mucosa grafting with the combined use of a pliable stent or fibrin glue for fixation.

Adult↗