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Biomedical subjects

Hirohiko Kakizaki

Publications and source records attributed to Hirohiko Kakizaki.

At least 19 recordsLinked to original sources
PubMed2006

The lower eyelid retractor consists of definite double layers.

PURPOSE: To examine whether the lower eyelid retractor consists of a single layer or multiple layers. DESIGN: Retrospective clinical case series and dissectional study. PARTICIPANTS: Fifty-one lower eyelid retractors (31 right, 20 left) of 44 patients (ages, 63-95 years) during entropion surgeries and 10 lower eyelids (5 right, 5 left) of 5 Oriental cadavers (73-91 years old at death) were observed macroscopically. Specimens from 20 postmortem lower eyelids of 12 Orientals (11 right, 9 left; 66-96 years old at death) were used for microscopic observations. METHODS: Macroscopically, we bluntly or, in parts, sharply dissected lower eyelid retractors into 2 layers during entropion surgeries. Cadaveric lower eyelids also were used to investigate relationships between the lower eyelid retractor and the Lockwood ligament. Cadaveric lower eyelids with sagittal full-thickness sections of the central part were examined microscopically using Masson trichrome staining. MAIN OUTCOME MEASURES: Anatomical findings in the lower eyelid retractor. RESULTS: Lower eyelid retractors easily were detached into 2 layers. Macroscopically, the anterior layer was defined as a coarse tissue continuing from the Lockwood ligament, which joined with the lower orbital septum, and constituted the lower conjoined fascia. The posterior layer appeared to be a dense fibrous sheet with a lustrous surface. Microscopically, the lower eyelid retractor consisted of a definite double layer. The anterior layer, a coarse fibrous tissue, consisted of the suborbicularis fascial layer, orbital septum, and superficial part of the capsulopalpebral fascia, which continued to the anterior lamellae of the lower eyelids. The posterior layer consisted of dense fibers of the capsulopalpebral fascia with smooth muscle continuing to the tarsus. CONCLUSIONS: The lower eyelid retractor consists of a definite double layer. The posterior dense layer containing smooth muscle is the main tractional component of the lower eyelid retractor.

Aged↗
PubMed2006

Histopathology of blepharoptosis induced by prolonged hard contact lens wear.

PURPOSE: To clarify histopathologically the structural features of blepharoptosis in prolonged hard contact lens wearers. DESIGN: Retrospective case-control study. METHODS: Biopsy specimens from identical sites at the levator aponeurosis and Mueller muscle from 15 long-term hard contact lens wearers were examined histopathologically (group 1). They comprised two men and 13 women with bilateral blepharoptosis ranging in age from 26 to 59 years (mean +/- SD, 44.4 +/- 10.70 years). The average length of hard contact lens wear was 25.4 years (range 12 to 40 years), and the average spherical equivalent refractive error was -9.100 diopters (range -2.825 to -20.375 diopters). We also examined specimens from 15 patients with involutional blepharoptosis who underwent levator resection; they comprised three men and 12 women ranging in age from 64 to 79 years (mean +/- SD, 72.3 +/- 4.38 years). RESULTS: All patients in group 1 manifested fibrosis and negligible fatty degeneration in Mueller muscle. In group 2, we detected mild fibrosis in Mueller muscle and fatty degeneration of the aponeurosis and Mueller muscle. CONCLUSIONS: Prolonged hard contact lens wear induces fibrosis in Mueller muscle and may result in contact lens-induced blepharoptosis.

Adult↗
PubMed2006

Adult medial orbital wall trapdoor fracture with missing medial rectus muscle.

We report the case of a 28-year-old man presenting with a medial orbital wall trapdoor fracture with a missing medial rectus muscle. We believe this to be the first case report of an adult medial orbital wall trapdoor fracture. Trapdoor fractures most commonly occur in the pediatric population, and those involving the medial orbital wall generally occur in areas with less developed ethmoid air cells. Since the present case followed neither pattern, a different injury mechanism was considered. The ethmoid air cells in this case were well developed, which may have played an important role in the pathogenesis of this adult medial orbital wall trapdoor fracture. Based on our findings, we propose a possible mechanism for a medial orbital wall trapdoor fracture in an adult. The cellular frames enable the medial bone to shift just minimally, regardless of the high orbital pressure during a blow. The excess volume of the orbital content escapes into the cells through narrow cracks; therefore, after a blow, it cannot move back completely into the orbit. Consequently, it pushes the shifted bone towards the orbit, becoming trapped in a manner similar to that of a check-valve mechanism.

Adult↗
PubMed2006

An anomalous muscle linking superior and inferior rectus muscles in the orbit.

Dissections of the bilateral orbits in a 45-year-old female cadaver, who had no ocular movement disorders in her lifetime, revealed anomalous muscles linking the superior and inferior rectus muscles. The muscles, situated between the optic nerve and the lateral rectus muscle, originated from the annulus of Zinn and branched off two heads; one inserted into the medial inferior side of the superior rectus muscle and the other inserted into the central superior side of the inferior rectus muscle. Each insertion was located on a distal site of the myoneural junction of each rectus muscle. Histological investigations showed that the muscles had a striated muscle structure. No definite nerve insertion was observed in the muscles. Although this type of anomalous muscle has been reported in a few Caucasian cases, the present study is the first report in an Asian person. Anomalous orbital structures, which are a rare cause of strabismus, are important in the differential diagnosis of intra-orbital space-occupying lesions, rather than the differential diagnosis of strabismus.

Asian People↗
PubMed2006

Myoneural junctions of extraocular muscles: distances from the orbital rim and widths.

PURPOSE: To examine both the distances from the orbital rim to the myoneural junctions (MNJs) and the widths of the MNJs of all extraocular muscles. METHODS: Six orbits of 3 post-mortem cadavers were used. The cadavers (1 female and 2 males) were all Japanese with an average age of 76.3 years. The MNJs of the extraocular muscles and their motor nerves were exposed, and then the distance from the orbital rim to each MNJ and the width of each MNJ were examined. RESULTS: The distance from the orbital rim to each MNJ in the 6 extraocular muscles ranged from 24.4 to 33.6 mm and the width of each MNJ ranged from 5.0 to 8.5 mm. CONCLUSIONS: It is essential for orbital surgeons to understand both the distance from the orbital rim to MNJs and the widths of MNJs. This information not only aids the understanding of MNJ damage, but also prevents iatrogenic nerve impairment during orbital surgery.

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PubMed2006

Lateral canthal support system in Japanese.

The present study aimed to elucidate microscopically the precise structure of the generally termed 'lateral canthal tendon' (LCT). Specimens from 9 post-mortem lower eyelids of 6 Japanese aged from 72 to 91 years old at death were fixed in 10% buffered formalin, and microscopically examined. Specimens were excised as exenterated samples including an area 5 mm wider than the orbital aperture. The removed contents were further incised longitudinally on the central eyelid and also incised parallel to the upper eyelid margin on the site 3 mm from its margin. After the preparation of microscopical examination, sections of all 9 eyelids were stained with Hematoxylin and Eosin. We found that the structure generally termed LCT consisted of two definitive different layers microscopically. The superficial layer was only an orbital septum (septal band). It was mainly constituted of thick fibers between adipose-rich tissues. The deep layer continued from the tarsus and projected posteriorly; which was a ligament (tarsoligamentous band). This tissue was constituted by thin, minute fibers with little adipose tissues. The structure generally termed LCT is not a tendon but a complex constitution of an orbital septum and a ligament; which we named, in a mass, 'lateral canthal bands', cooperatively supporting the lateral canthus.

Aged↗
PubMed2005

Expression profile of heat shock protein 108 during retinal development in the chick.

In the developing chick retina, heat shock protein 108 (HSP108), which exhibits transferrin binding activity, has been demonstrated at the mRNA level, while transferrin shows two expression peaks. Here, we investigated the expression profile of HSP108 in the developing chick retina at the protein level. The localization of HSP108 in embryonic days 15 (E15), E18, and postnatal day 2 (P2) chick retina was examined immunohistochemically using monoclonal antibody 9G10 specific for chick HSP108, while the expression levels of HSP108 in developing chick retina from E12 to P2 and adult were measured by Western blot analysis. HSP108 was expressed in the ganglion cell layer, inner nuclear layer, outer plexiform layer, outer nuclear layer, inner segments of photoreceptors and retinal pigment epithelium. Two peaks of HSP108 expression were found at around E13 and E18, respectively. Since the two HSP108 peaks appeared to be correlated with the transferrin expression peaks during retinal development, HSP108 may be associated with iron metabolism during the development of the retina.

Animals↗
PubMed2005

The lacrimal canaliculus and sac bordered by the Horner's muscle form the functional lacrimal drainage system.

PURPOSE: To clarify the relationship between the orbicularis oculi muscle, lacrimal canaliculus, and lacrimal sac and to propose a new theory of the lacrimal drainage system. DESIGN: Dissection study. PARTICIPANTS: Sixteen Asian cadavers (29 upper eyelids). METHODS: Gross dissections of the orbicularis oculi muscle in the medial canthus of 10 Asian cadavers were performed, and the relationship between the orbicularis oculi muscle, lacrimal canaliculus, and lacrimal sac was examined. The upper eyelids of the remaining 6 cadavers were dissected grossly, and sections of the lacrimal sac, common lacrimal canaliculus, and upper canaliculus were examined microscopically. The relationship between the lacrimal passage and its surrounding tissues also was examined. RESULTS: The lacrimal canaliculus and sac both were divided into 2 distinct compartments in relation to the Horner's muscle. The upper half of the lacrimal sac was related to the Horner's muscle through the posterior branch of the medial canthal tendon and connective tissue, and the lower half was related to the capsulopalpebral fascia and orbital fat. The lateral part of the lacrimal canaliculus was covered with the Horner's muscle. The medial part of the lacrimal canaliculus, namely the common lacrimal canaliculus, was not covered by the Horner's muscle, but was covered by the preseptal and orbital parts of the orbicularis oculi muscle on the anterior surface. CONCLUSIONS: The lacrimal canaliculus and sac were divided into 2 distinct compartments by the Horner's muscle, and it is possible that both contribute to the lacrimal drainage system.

Aged↗
PubMed2005

Fibrous connective tissue between Müller's muscle and the palpebral conjunctiva as a reinforcement structure and a natural barrier for the upper eyelid.

This study was performed to illustrate and discuss the significance of fibrous connective tissue between the Müller's muscle and the palpebral conjunctiva. Nine upper eyelids of 6 Oriental cadavers were microscopically examined; ages at death ranged from 72 to 91 years. Tissue of the posterior lamella of the upper eyelid was removed without the orbital septum and orbital fat. Removed eyelids were incised perpendicularly at the center of the eyelid. After pretreatment, sliced sections were stained with Hematoxylin and Eosin and examined microscopically. A thick fibrous connective tissue was found to exist between the Müller's muscle and the palpebral conjunctiva. The connective tissue continued proximally to the intermuscular transverse ligament and was distally attached to the posterior site of the upper aspect of the tarsus. All cases showed infiltration of lymphocytes from the conjunctiva; however, these were completely blocked by the fibrous connective tissue and never reached Müller's muscle. This connective tissue supports eyelid traction and is a natural barrier for the Muller's muscle against conjunctivitis.

Aged↗
PubMed2005

The levator aponeurosis consists of two layers that include smooth muscle.

PURPOSE: To investigate the two-fold structure of the levator aponeurosis, which is partly composed of independent smooth muscles. MATERIALS AND METHODS: Fifteen upper eyelids of 12 Asian postmortems, with age at death ranging from 72 to 91 years, were examined. In 9 eyelids, posterior lamella tissue of the upper eyelid was removed to observe the stratified structures of the levator aponeurosis. Six full-thickness eyelids were used to observe the attachment site or the continuity between the levator aponeurosis and its surrounding tissues. The eyelids were incised perpendicularly in the center of the eyelid; samples were stained with Masson trichrome and antismooth muscle actin antibody and examined microscopically. RESULTS: Masson trichrome staining demonstrated the two-layered nature of the levator aponeurosis. The anterior layer was characterized by thick, robust fibrous tissue, and the posterior by thinner fibrous tissue. Although both layers contained muscle structures, the posterior layer contained more than the anterior. Immunostaining with antismooth muscle actin antibody revealed that the muscle in both layers was smooth muscle. The anterior layer continued to the orbital septum and the submuscular fibroadipose tissue; the posterior layers, located in front of Müller muscle and its tendon, attached to the anterior inferior one-third of the tarsus. Part of the anterior layer went through the orbicularis oculi muscle and attached to the subcuticular tissue. CONCLUSIONS: The levator aponeurosis is stratified, consisting of two layers than contain smooth muscle components in their proximal portions. It pulls mainly the preaponeurotic fat and anterior eyelid lamella. This partially regulates the tension of the eyelid and contributes to the ordered movement of the upper eyelid.

Actins↗
PubMed2005

The levator aponeurosis consists of two layers that include smooth muscle.

PURPOSE: To investigate the two-fold structure of the levator aponeurosis, which is partly composed of independent smooth muscles. MATERIALS AND METHODS: Fifteen upper eyelids of 12 Asian postmortems, with age at death ranging from 72 to 91 years, were examined. In 9 eyelids, posterior lamella tissue of the upper eyelid was removed to observe the stratified structures of the levator aponeurosis. Six full-thickness eyelids were used to observe the attachment site or the continuity between the levator aponeurosis and its surrounding tissues. The eyelids were incised perpendicularly in the center of the eyelid; samples were stained with Masson trichrome and antismooth muscle actin antibody and examined microscopically. RESULTS: Masson trichrome staining demonstrated the two-layered nature of the levator aponeurosis. The anterior layer was characterized by thick, robust fibrous tissue, and the posterior by thinner fibrous tissue. Although both layers contained muscle structures, the posterior layer contained more than the anterior. Immunostaining with antismooth muscle actin antibody revealed that the muscle in both layers was smooth muscle. The anterior layer continued to the orbital septum and the submuscular fibroadipose tissue; the posterior layers, located in front of Müller muscle and its tendon, attached to the anterior inferior one-third of the tarsus. Part of the anterior layer went through the orbicularis oculi muscle and attached to the subcuticular tissue. CONCLUSIONS: The levator aponeurosis is stratified, consisting of two layers than contain smooth muscle components in their proximal portions. It pulls mainly the preaponeurotic fat and anterior eyelid lamella. This partially regulates the tension of the eyelid and contributes to the ordered movement of the upper eyelid.

Actins↗
PubMed2004

Causes of undercorrection of medial palpebral fissures in blepharoptosis surgery.

PURPOSE: To ascertain the cause of undercorrection of the medial palpebral fissure in blepharoptosis surgery. METHODS: Twelve upper eyelids of 6 Asian cadavers, 4 male and 2 female (average age at death, 77.5 years), were studied. After exposing the levator muscle by removing bone of the superior orbital rim, the levator muscle and medial and lateral horns of aponeurosis were observed. RESULTS: The levator muscle was located in the anterolateral direction. Bifurcation angles of the medial horn were steeper than those of the lateral horn, but the lateral horn was wider than the medial horn (Student's t test; P < 0.0001). The inferior edge of the superior expansion of the aponeurosis extensively covered the lateral horn but only slightly covered the medial horn. Accordingly, most of the medial horn was constituted by only the thin structure of the middle and inferior expansion of the aponeurosis. CONCLUSIONS: Because the medial horn is structurally weaker and less dynamic than the lateral horn, the lateral side of the aponeurosis is pulled more strongly than the medial, often resulting in medial undercorrection in blepharoptosis surgery. To prevent this, the medial part should be fixed more widely than the lateral.

Aged↗