Biomedical subjects

K Kani

Publications and source records attributed to K Kani.

At least 37 records · Page 2Linked to original sources

PubMed1996

A new method to selectively injure the optic nerve using argon-laser photocoagulation.

To create a model by noninvasive means for the study of Wallerian and transneuronal degeneration of the central nervous system, we devised a two-step argon laser photocoagulation (ALP) procedure with which we could selectively injure the optic nerve in rats. Changes in the optic nerve distal to the site of injury were studied histologically to evaluate this method; we succeeded in selectively and completely injuring the optic nerve. We found this ALP technique to be superior to either the panretinal or one-step photocoagulation method. Changes within astrocytes of the intracerebral optic tract and the lateral geniculate body in animals were also studied immunohistochemically following ALP and compared with those which follow enucleation. Reactive astrocytes with enhanced immunoreactivity for glial fibrillary acidic protein (GFAP) increased in number in the intracerebral optic tract and in the lateral geniculate body on the contralateral side of the optic injury in both groups of animals. The increased GFAP immunoreactivity was sustained for 6 weeks following injury; the proliferative tendency of the glial cells, shown by the bromodeoxyuridine method, peaked 3 days after injury and then decreased gradually. These glial responses in the optic tract and lateral geniculate body of animals subjected to ALP are similar to those of animals following enucleation. Our results indicate that this new technique for selectively and noninvasively injuring the optic nerve with ALP is applicable to the study of Wallerian and transneuronal degeneration.

Animals↗

PubMed1996

Volume measurement of horizontal extraocular muscles with magnetic resonance imaging.

The horizontal extraocular muscle volume of 11 normal adults and 3 ophthalmoplegic patients was measured with magnetic resonance imaging (MRI), using a 1.5 Tesla superconductive system which can provide T1 weighted images of 3 mm gapless slices of the orbit with the spin echo technique. The MRI film was projected and magnified on Kent paper with an overhead projector; muscle shapes were traced and cut from the paper. Muscle volume was defined as the total weight of the Kent paper shapes representing the muscles from all MRI slices. The average volumes of the medial and lateral rectus muscles (MRM, LRM) of the 11 subjects were 690 +/- 87 mm3 and 734 +/- 77 mm3. In two patients with peripheral nerve palsy, the small muscle volume was classified as atrophic; in the one patient with orbital myositis, the large muscle volume was classified as hypertrophic. This measurement technique is useful for evaluation of the extraocular muscles, especially in ophthalmoplegia.

Adult↗

PubMed1995

Histamine actions in dog retinal central arteries as compared to those in middle cerebral and temporal arteries.

PURPOSE: Mechanisms underlying the relaxant response to histamine were compared in isolated dog retinal arteries (branch of internal and external carotid arteries), middle cerebral arteries (branch of internal carotid artery) and superficial temporal arteries (branch of external carotid artery). METHODS: Changes in the isometric tension of helical strips of the arteries with and without the endothelium were recorded. RESULTS: Histamine produced concentration-related biphasic (phasic and sustained) relaxations in retinal arterial strips contracted partially with prostaglandin (PG)F2 alpha. Relaxations induced by histamine were not dependent on the endothelium. Treatment with cimetidine attenuated the sustained relaxation, whereas chlorpheniramine or indomethacin depressed the phasic relaxation. In addition, the phasic relaxant response to histamine was attenuated by tranylcypromine, a PGI2 synthesis inhibitor. In contrast, the amine-induced relaxant responses in dog middle cerebral arterial branch and temporal arteries were markedly suppressed by cimetidine alone. CONCLUSIONS: In dog retinal arteries, the phasic relaxation caused by histamine is mediated by PGI2 in association with activation of the H1 receptor subtype in subendothelial tissues, possibly smooth muscle, and the sustained relaxation is evoked by direct stimulation of the H2 receptor subtype in smooth muscle. The histamine-induced relaxation in temporal and distal middle cerebral arteries is associated solely with a stimulation of H2 receptors in smooth muscle.

Animals↗

PubMed1995

[Incidence of acute idiopathic optic neuritis and its therapy in Japan. Optic Neuritis Treatment Trial Multicenter Cooperative Research Group (ONMRG)].

Data on the incidence of and treatment for acute idiopathic optic neuritis were obtained by questionnaire sent to departments of ophthalmology, university hospitals, and general hospitals throughout Japan. Inquiry was made as to the number of cases which developed idiopathic optic neuritis from April 1992 to March 1993 along with their clinical features. The response rate was 53.6%. There were a total of 550 cases, and the male to female ratio was 1:1.22. Patients 14 to 55 years old were 65.9%; bilateral involvement: 28.2%; recurrence: 18.6%; positive past history of the other eye; 7.5%. Assuming the answering rate to be 100% and two thirds of the patients to be included, annual incidence of this disease (the annual number of patients) was determined to be 1.62 for an adult population of 100,000 (1.03 cases/100,000 people). Tochigi, Tokyo, Kanagawa, Hyogo, Wakayama, Okayama, Yamaguchi, Tottori, Shimane, Ehime, and Fukuoka showed an annual incidence exceeding 2.0/100,000 adults. At more than 95% of all medical institutions questioned, patients with optic neuritis were usually treated with systemic corticosteroids. Oral corticosteroid therapy, which was shown in a recent study in USA to be contraindicated, was still being used at 15% of the institutions.

Acute Disease↗

PubMed1994

Dipeptidyl peptidase IV from porcine seminal plasma: purification, characterization, and N-terminal amino acid sequence.

Dipeptidyl peptidase IV (DPP IV) was purified to homogeneity from porcine seminal plasma by polyacrylamide gel electrophoresis (PAGE). The molecular weight of the purified enzyme was calculated to be approximately 290,000 on PAGE in the absence of sodium dodecyl sulfate (SDS) and 310,000 on Sephacryl S-300 HR column chromatography, and to be 115,000 and 105,000 on SDS-PAGE in the absence and presence of beta-mercaptoethanol. The enzyme is suggested to be composed of three identical subunits. The enzyme rapidly hydrolyzed the substrate Gly-Pro-MCA, and weakly the substrate Lys-Ala-MCA. It was strongly inhibited by diisopropylphosphofluoridate (DFP), and moderately by both phenylmethyl-sulfonyl fluoride (PMSF) and 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF). It was also strongly inhibited by zinc ion. The amino acid sequence of the first 18 residues of the enzyme was Asn-Lys-Gly-Thr-Asp-Asp-Ala-Ala-Ala-Asp-Ser-Arg-Arg- Thr-Tyr-Thr-Leu-Thr-. This sequence was highly homologous to the sequences in the rear of the transmembrane site of human and rat liver DPP IVs and mouse thymus DPP IV. The native DPP IV is suggested to be released into the seminal plasma after the cleavage of the hydrophobic N-terminal domain by chymotrypsin-like or pepsin-like enzymes. Other properties of DPP IV including kinetic parameters, pH stability and heat stability were characterized.

Amino Acid Sequence↗

PubMed1993

Appearance of calretinin-immunoreactive neurons in the upper layers of the rat superior colliculus after eye enucleation.

The effects of retinal deafferentation on a calcium-binding protein, calretinin, in the upper layers (superficial gray layer and optic nerve layer) of the rat superior colliculus were examined. In intact rats and on the ipsilateral side of unilaterally eye-enucleated rats, the superficial gray layer and optic nerve layer contained a few dispersed calretinin-immunoreactive cells. On the contralateral side to the enucleation, the number of immunostained cells in the superficial gray layer and optic nerve layer was increased. These findings suggest that retinal deafferentation results in an increase in contents of calretinin in some cell bodies within the upper layers of the superior colliculus.

Afferent Pathways↗

PubMed1993

Nitric oxide-mediated retinal arteriolar and arterial dilatation induced by substance P.

PURPOSE: The present study was undertaken to compare vasodilatations caused by substance P in retinal arterioles in vivo and in the extraocular retinal central arteries in vitro, and to analyze the mechanisms of its action. METHODS: In the in vivo study, changes of the retinal arteriolar diameter were continuously measured using a retinal fundus camera. In the in vitro study, changes in the isometric tension were recorded in helical strips of extraocular retinal arteries with and without the endothelium, exposed to aerated bathing media. RESULTS: In anesthetized dogs, infusions of substance P into the carotid artery produced a dose-dependent dilatation of the intraocular retinal arteriole; the maximal response was obtained about 15 seconds later. The vasodilator response was significantly attenuated by treatment with NG-nitro-L-arginine (L-NA), a nitric oxide (NO) synthase inhibitor, and the inhibition was reversed by L-arginine. On the other hand, vasodilatations caused by nitroglycerin were not influenced by L-NA and L-arginine. In the isolated retinal artery just before entering into the eyeball, the addition of substance P produced a concentration-dependent relaxation only when the endothelium of the strips was intact. Removal of the endothelium abolished the response. The peptide-induced relaxation was abolished by L-NA, whereas relaxations caused by NO and nitroglycerin were unaffected. The inhibitory effect of L-NA was reversed by L-arginine but not by D-arginine. Treatment with methylene blue or oxyhemoglobin abolished the relaxation induced by substance P, NO, and nitroglycerin. CONCLUSIONS: Substance P-induced retinal arteriolar dilatation in vivo appears to be mediated by NO synthesized from L-arginine possibly in the endothelium. The endothelium-dependency would be supported by the findings obtained from isolated retinal arteries.

Animals↗

PubMed1993

Long-term corneal endothelial changes after intraocular lens implantation. Anterior vs posterior chamber lenses.

The use of semiflexible anterior chamber intraocular lenses, widespread during the early 1980's, has been abandoned due to the many complications associated with their use. Patients who received these lenses currently represent the majority of patients with pseudophakic bullous keratopathy. We studied the morphologic characteristics of the corneal endothelium in 20 patients who had undergone extracapsular cataract extraction followed by anterior chamber or posterior chamber intraocular lens implantation. Specular microscopy and computer-assisted morphometry were performed preoperatively, 3 months postoperatively, and once a year thereafter. The follow-up period for each subject was 5 years or longer. The endothelial cell density of the central cornea in the anterior chamber lens group decreased from 304 to 196 (x 10 cells/mm2), and in the posterior chamber lens group decreased from 315 to 269 (x 10 cells/mm2). Four patients in the anterior chamber lens group developed pseudophakic bullous keratopathy 6 or 7 years after surgery. Severe endothelial cell loss and morphologic change were seen in patients who received anterior chamber lenses.

Aged↗

PubMed1993

[Volume measurement of the horizontal extraocular muscles using magnetic resonance imaging].

The volume of the horizontal extraocular muscles of 11 normal adults and three patients with ophthalmoplegia was measured using magnetic resonance imaging (MRI). The MRI examinations were carried out with a Signa Advantage, 1.5 tesla superconductive magnetic system manufactured by General Electric. This method employs the spin echo technique with a 3.0 mm gapless slice, a 350 ms. repetition time, and a 17.0 ms. echo time. The MRI films were projected and magnified on Kent paper using an overhead projector. Then the shapes of the horizontal extraocular muscles were traced. The volume of the muscles was measured as the total weight of Kent papers which were cut out from muscle shapes in all the slices. The average volume of the normal medial and lateral rectus muscles was 690 +/- 87 mm3 and 734 +/- 77 mm3, respectively. Two cases with peripheral nerve palsy showed typical atrophy of the paretic muscles. A case with orbital myositis showed typical hypertrophy of the inflamed muscles. This measurement may prove useful in the analysis and evaluation of extraocular muscles, especially in ophthalmoplegia.

Adult↗

PubMed1992

Immunohistochemical localization of calretinin in the rat lateral geniculate nucleus and its retino-geniculate projection.

In the present study, we examined the distribution of calretinin-immunoreactive neuronal cell bodies and fibers in the lateral geniculate nucleus of the rat. In normal rats, clusters of immunoreactive cell bodies were found in: (i) the rostral portion of the ventral lateral geniculate nucleus pars medialis (VLGM), (ii) the intergeniculate leaflet (IGL), (iii) the intermediate region between the VLGM and the ventral lateral geniculate nucleus pars lateralis (VLGL), (iv) the caudomedial portion of the VLGM, and (v) the caudolateral portion of the VLGM. In the dorsal lateral geniculate nucleus (DLG), immunoreactive cell bodies were rarely observed. After uni- or bilateral eye enucleation, no significant alteration in the morphological features or distribution of immunoreactive cell bodies was detected in the lateral geniculate nucleus. In normal rats, immunoreactive fibers formed dense plexuses in: (i) the DLG, (ii) the external layer of the VLGL, (iii) the internal layer of the VLGL, (iv) the IGL, (v) the caudomedial portion of the VLGM, and (vi) the optic tract. After unilateral eye enucleation, immunoreactive fibers in the external layer of the VLG and in the optic tract almost totally disappeared on the contralateral side to the lesion. Unilateral eye enucleation caused a significant decrease of immunoreactive fibers in the DLG and in the internal layer of the VLGL, but a substantial number of immunoreactive fibers still remained there. In the IGL and the caudomedial portion of the VLGM, no observable alteration in the distribution of immunoreactive fibers was detected after uni- or bilateral eye enucleation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Transient patterns of serotonergic innervation in the rat visual cortex: normal development and effects of neonatal enucleation.

The transient aggregation of serotonin (5-HT)-containing fibers in the early development of rat visual cortex was examined immunohistochemically. The aggregation of 5-HT immunoreactive (IR) fibers consisted of three stages which were classified according to the course of time and degree of space occupied. The primary aggregation appeared in the subplate and moved upward along the development of the cortex. The aggregation proceeded to the secondary stage in presumptive layer IV. The fibers extended in a column-like structure following the secondary aggregation and formed the tertiary aggregation. The upper edge of the tertiary aggregation formed a lattice-like pattern in layer I and its structure was recognized to be similar to the structure of a 'blob' which characterizes the primary visual cortex in monkey. This transient aggregation of 5-HT-IR fibers began in the subplate of the anterior visual cortex on postnatal day 2 (PND 2) and progressed towards the posterior. On PND 11, the secondary and tertiary aggregations were completed in the entire region. No further aggregation of 5-HT-IR fibers was observed on PND 15. The anterior-to-posterior axis in the aggregation process corresponds to the direction of differentiation in the layer structure of cortex. In order to investigate the relationship between the transient aggregation of 5-HT-IR fibers and the development of the visual pathway, the secondary and tertiary aggregation on PND 11 were observed after postnatal monocular or binocular enucleation. Enucleation of eye balls did not affect either the area occupied by the 5-HT-IR fibers in the secondary aggregation or the number of column structures in the tertiary aggregation. However, the contralateral and ipsilateral cortices of monocularly enucleated cases were irregularly shaped in the secondary aggregation. The distribution of 5-HT-IR fiber terminals in the binocular area (Oc1B) increased in density on the contralateral side in the monocular enucleation, while that of both sides in the binocular enucleation was of non-homogeneous density and were shaped irregularly. The above results suggest that the transient aggregation of 5-HT-IR fibers observed in the early stage of development of visual cortex is regulated primarily by the intrinsic factors, and that extrinsic factors, such as visual pathway input, affect the aggregation within the boundary of such intrinsic factors. That is, the visual pathway input and the input balance from both eyes affect the distribution density of 5-HT-IR fibers and the shape of the visual cortex, respectively.

Animals↗

PubMed1992

[Transient patterns of serotonergic innervation in the rat visual cortex--normal development and effects of enucleation].

Serotonergic innervation formed transient dense aggregation in all rat primary sensory areas during early postnatal development. In the normal rat visual cortex, there were three stages in the transient aggregation of serotonin immunoreactive fibers from postnatal day (PND) 2 to 15. Primary aggregates appeared in the subplate prior to the differentiation of layer IV, and moved upward to the lower layer of cortical plate to form secondary aggregates. Secondary aggregation gave rise to ascending fibers on the cortical surface which were roughly grouped in columns (tertiary aggregation). The serotonin fibers of the tertiary aggregates were arranged in a lattice-like pattern in layer I, and were significantly altered either in size of distribution area or column number after monocular or binocular enucleation. These data indicate that the lattice-like pattern of serotonin innervation in neonatal rats may be an evolutionary precursor of the "blobs" seen in the higher primates.

Animals↗

PubMed1991

Investigations of origins of serotonergic projection to developing rat visual cortex: a combined retrograde tracing and immunohistochemical study.

The present study investigated whether the raphe neurons which give rise to the transient serotonergic fibers in the visual cortex of neonatal rats persist or disappear as the rats mature. Three experiments were performed employing the WGA-apoHRP-Au retrograde transport technique in conjunction with 5-HT or WGA-HRP immunohistochemical staining. WGA-apoHRP-Au was injected into the primary visual cortex of all rats 9 days postnatally. In the first experiment, the animals were examined after 2 days; retrogradely labeled cells were observed in the dorsal raphe nucleus (DR), the median raphe nucleus (MR), and in the B9 and B6 cell groups; the majority (82.5%) of the cells was serotonergic. In the second experiment, the examinations took place following a survival time of 8 weeks: virtually all of the original raphe-visual cortical serotonergic neurons were found to the present. In the third experiment, also performed after 8 weeks relabeling the raphe-visual cortical neurons by WGA-HRP, it was found that 37.2% of the raphe neurons which had projected to the neonatal visual cortex no longer possessed such projections.

Aging↗

PubMed1991

Significant non-serotonergic raphe projection to the visual cortex of the rat. An immunohistochemical study combined with retrograde tracing.

The present study investigated the distribution of serotonergic and non-serotonergic raphe neurons with direct projections to the visual cortex. The study employed the WGA-apoHRP-Au retrograde transport technique combined with 5-HT immunohistochemical staining. Retrogradely labeled cells were observed in the dorsal raphe nucleus, the median raphe nucleus, and in the B9 and B6 cell groups. One notable finding was the great number of retrogradely labeled, non-5-HT immunoreactive cells. The average percentages of such cells in the various raphe regions were as follows: DR: 52% (n = 401); MR: 35% (n = 311); B9: 24% (n = 129); B6: 95% (n = 200). The present study demonstrated the presence of a significant proportion of non-serotonergic raphe region neurons projecting to the primary visual cortex in the rat. It is suggested that these neurons may complement the aminergic neurons as part of the ascending system which controls the functions of the visual cortex.

Animals↗

PubMed1991

[A double-labeling study of serotonin neurons that project to the visual cortex of developing rat brain].

Immunohistochemical studies of developing rat brains revealed aggregation of serotonin terminal fibers in the visual cortex at from 7 to 14 postnatal days. This aggregation is transient, disappearing 2 weeks after birth. The cells of origin of these serotonin terminals were investigated using double-labeling with retrogradely transported WGA-apoHRP-Au and serotonin immunohistochemistry. WGA-apoHRP-Au was injected into the rat visual cortex on the 9th day after birth. The rats were allowed to survive for 2 days and sacrificed with perfusion. Cryostat sections of the brain were processed with silver-enhancement to develop the retrogradely transported WGA-apoHRP-Au, and then serotonin immunohistochemistry was performed. Double-labeled cells that were labeled with WGA-apoHRP-Au and serotonin-immunoreactive were found mostly in the raphe medianus and raphe dorsalis in rostral and caudal sections of the mesencephalon, respectively.

Animals↗

PubMed1990

A multipurpose dye laser photocoagulation system.

We modified a single argon/dye laser photocoagulator by adding two optical fibers so that it could be used with a slit-lamp microscope, an operating microscope, and with an endophotocoagulation probe. One fiber is attached to a nearby slit-lamp microscope; the other extends approximately 70 m and can be connected to either an operating microscope or an endophotocoagulation probe. An electrically-operated mirror inside the machine controls which of the two fibers the laser beam passes through. Separate control boxes for each fiber permit direct regulation of the photocoagulation process in all situations.

Argon↗

PubMed1990

[Computed tomography of skeletal muscles in myotonic muscular dystrophy].

The computed tomography (CT) of skeletal muscles was performed on 12 patients with myotonic muscular dystrophy (MyD). We have sliced at seven levels; those are 1. neck level-at the level of thyroid cartilage 2. shoulder girdle level-at the level of upper edge of sternum 3. upper arm level-at the level of middle of upper arm 4. abdominal level-at the level of L3 vertebra 5. pelvic girdle level-at the level of middle inguinal ligament 6. thigh level-at the level of middle of thigh 7. lower leg level-at the maximum size level of lower leg. The characteristic changes of MyD are; the sternocleidomastoid muscles are most severely affected, and the paravertebral and straight abdominal muscles also tend to be severely atrophied with lower CT density. Concerning thigh levels, the deeply located muscles and muscles for extension are predominantly affected. At the lower leg levels, the calf muscles are severely affected. The muscles of levator scapulae, trapezius, psoas major, iliopsoas, gluteus, and tibialis posterior tend to be preserved. In the tight, the compensatory hypertrophy is observed often in the rectus femoris muscles and rarely in the gracilis muscles with the involvements of the agonist muscles. It might be also important to examine the changes of muscles as a whole and to know the grade of atrophy for planning the life style. The CT examination would be recommended by this standpoint.

Adult↗

PubMed1989

Dopaminergic cells in the superior cervical ganglion of the rat: light and electron microscopic study using an antibody against dopamine.

So-called small intensely fluorescent (SIF) cells were visualized immunohistochemically using a newly developed anti-dopamine (DA) serum in the rat superior cervical ganglia (SCG), both light and electron microscopically. Specificity of the anti-DA serum was tested in a control test and enzyme-linked immunosorbent assay (ELISA). DA-immunoreactivity was found in a subpopulation of SIF cells, but not in principal neurons. Ultrastructurally, DA-immunoreactivity was noticed in the cytoplasmic matrix and vesicles of perikarya, dendritic processes and terminals of SIF cells. DA-labeled terminals made symmetrical synaptic contacts with unlabeled principal neurons. These findings provide a morphological basis for the role of dopaminergic SIF cells as interneurons.

Animals↗