Biomedical subjects

N Tachi

Publications and source records attributed to N Tachi.

At least 37 records · Page 2Linked to original sources

PubMed2000

[Clinical features of idiopathic macular holes].

PURPOSE: The purpose of this study was to evaluate the clinical features of idiopathic macular holes. MATERIALS AND METHODS: The clinical features were examined in consequentive 526 eyes of 480 patients with idiopathic macular hole who underwent vitrectomy. RESULTS: Sixty-seven% of the patients were female. The mean onset age was 64.4 years of age and 60% of the cases were in their 60's at the time of onset. The mean refractive value was -0.66 dioptor and 40% of the cases were emmetropia with a refractive value between -1.0 dioptor and +1.0 dioptor. The onset age was positively correlated with refractive value. The visual acuity was negatively correlated with onset age, duration after onset, and the size of the macular hole. The duration was positively correlated with onset age. The size of the macular hole was positively correlated with age and duration. The factors for good visual acuity were determined by bilaterality, youth, or small size. Also we found the factors for large size of macular holes to be female gender, long duration of the hole, being in stage 4, and low visual acuity. CONCLUSIONS: The incidence of idiopathic macular hole is seen more in eyes of patients in their 60's and in emmetropic eyes. Patients with myopic eyes tend to have younger onset. The size of the macular hole in females tends to be larger than in males.

Adult↗

PubMed1999

Charcot-Marie-Tooth disease type 1A duplication by PCR analysis.

By generating new junctional fragments from the recombinant Charcot-Marie-Tooth (CMT) 1A-REPs in CMT1A patients, a 3.2-kb recombination hot spot is observed in three quarters of CMT1A patients. By a polymerase chain reaction (PCR) method the authors analyzed eight patients CMT1A duplication, confirmed by Southern blot, to detect a recombination hot spot. Four patients had a novel 3.2-kb junctional fragment by PCR analysis. These four patients with a novel 3.2-kb junctional fragment had an abnormal 1789-bp fragment in addition to 1986-bp fragment after NsiI digestion (type 1). One patient who demonstrated no novel 3.2-kb junctional fragment had an abnormal 336-bp fragment in addition to 265 bp (type 2). Three patients with CMT1A duplication were not diagnosed as having CMT1A on the basis of PCR analysis. The PCR-based DNA test is valuable for screening to detect CMT1A duplication.

Adolescent↗

PubMed1999

Vitrectomy for macular edema combined with retinal vein occlusion.

This study was performed in order to evaluate the effect of vitrectomy in eyes with retinal vein occlusion associated with macular edema. Twenty-nine years eyes (27 patients) with branch retinal vein occlusion (BRVO), and 14 eyes (13 patients) with central retinal vein occlusion (CRVO) both associated with macular edema underwent phacoemulsification, intraocular lens implantation, pars plana vitrectomy and peeling of the posterior hyaloid membrane. Follow-up ranged from 12 to 32 months. Macular edema was reduced, and visual improvement was observed (p < 0.0001 in BRVO, p = 0.0257 in CRVO, paired t-test). Visual outcome was better in eyes with better visual acuity before surgery. Early vitrectomy may be recommended for retinal vein occlusion associated with macular edema.

Aged↗

PubMed1999

Cystotomy for diabetic cystoid macular edema.

The purpose of this study was to evaluate the role of vitrectomy with cystotomy in the treatment of diabetic cystoid macular edema (CME). Among 22 eyes of 21 patients with diabetic CME underwent phacoemulsification, intraocular lens implantation, pars plana vitrectomy, induction of posterior vitreous detachment, and cystotomy or cystectomy. Follow-up ranged from 3 to 29 months. Under biomicroscopic examination, Cystoid macular edema was eliminated in 16 of 22 eyes during the follow-up period. Ring-shaped residual edema was observed in one eye. Corrected visual acuity improved in 7 of 22 eyes by more than one Snellen line (P = 0.0391, paired t-test), remained the same in 13 eyes, and decreased by more than one line in 2 eyes. This pilot study shows that cystotomy may have a role in the treatment of cystoid macular edema in diabetic patients.

Aged↗

PubMed1999

Keratoacanthoma centrifugum marginatum arising from a scar after skin injury.

Among the variants of solitary keratoacanthoma, keratoacanthoma centrifugum marginatum (KCM) is characterized by the lack of a tendency toward spontaneous remission and by continuous centrifugal spread. We describe a case of KCM arising from the scar after an old skin injury. The lesion appeared on the dorsum of the right hand, grew peripherally for 30 months, and became a tumor with a multinodular margin and central atrophy. A biopsy specimen from the edge of the tumor showed features resembling typical solitary keratoacanthoma.

Aged↗

PubMed1999

Expression of the myotonic dystrophy locus-associated homeodomain protein in congenital myotonic dystrophy.

DM locus-associated homeodomain protein (DMAHP), a newly recognized homeodomain protein, is a candidate flanking gene and expressed in various tissues. We examined the expression of the DMAHP in tissues from a congenital myotonic dystrophy patient in comparison to that of control tissues by using semiquantitative reverse transcriptase-polymerase chain reaction. Reduced expression of DMAHP was observed in tissues from the patient with congenital myotonic dystrophy. This finding supports that reduced expression of DMAHP is related to the CTG repeat expansion.

Female↗

PubMed1998

A small direct tandem duplication of the myelin protein zero gene in a patient with Dejerine-Sottas disease phenotype.

We present a male patient with Dejerine-Sottas disease phenotype, who had a small direct tandem duplication of the Po gene. The pathology of the sural nerve showed hypomyelinated fibers with absence of active demyelination and onion-bulb formations composed of two parallel layers of basement membrane, consistent with congenital hypomyelination neuropathy (CHN). However, his clinical features were more severe than those of previously reported CHN patients. A GGCA insertion was identified at the position of nucleotide 560 in the myelin protein zero (Po) gene. This insertional mutation was located in exon 4 coding for the transmembrane domain of the Po gene and caused a shift of reading frame, creating a stop codon. The mutation of the transmembrane domain probably has the largest impact on Po function. The mutation was not identified in both parents.

Child↗

PubMed1998

A child case of haemophagocytic syndrome associated with cryptococcal meningoencephalitis.

A previously healthy 12-year-old Japanese girl developed meningoencephalitis due to Cryptococcus neoformans. During the course of her illness she suffered persistent high fever, severe pancytopenia, hypercytokinemia and liver dysfunction. Laboratory findings, including results of a bone marrow examination, strongly indicated complication by haemophagocytic syndrome (HPS). The preceding cryptococcal infection was thought to be a cause of the HPS because no other viral or bacterial infection could be confirmed. The girl died of acute respiratory failure during the progressive course of HPS. This may be the first reported case of HPS due to cryptococcal infection in an otherwise healthy child.

Child↗

PubMed1998

Phenotypic variability in a family with a mitochondrial DNA T8993C mutation.

Two patients are described in a family with a mitochondrial DNA T8993C point mutation. Patient 1, the proband, was a 4-year-old male, and his clinical features were consistent with those of Leigh syndrome, including lactic acidosis, motor development delay, and symmetric basal ganglia lesions on magnetic resonance imaging (MRI). His mental development was delayed mildly, but he has not demonstrated neurologic deterioration. Patient 2 was his maternal aunt. She developed her first neurologic sign at 18 months of age, thereafter her development ceased and regressed. She had lost her head control and become bedridden by 4 years of age and died at 20 years of age, demonstrating a more severe clinical course than that of Patient 1. Analysis of mitochondrial DNA from peripheral leukocytes of Patient 1 revealed a T8993C mutation of 99%. Patient 2 was demonstrated to have the same mutation at high abundance (99%) in the frozen myocardium and in the formaldehyde preserved spinal cord, with only 18% mutant mitochondrial DNA present in the formaldehyde preserved sciatic nerve. The mother of Patient 1, who was phenotypically normal (sister of Patient 2), had 35% mutant mitochondrial DNA in peripheral leukocytes. The authors' findings suggest that T8993C phenotypes are highly variable and that the proportion of the mutant mitochondrial DNA may vary among tissues and not correlate well with clinical severity.

Base Sequence↗

PubMed1998

Fine mapping of de novo CMT1A and HNPP rearrangements within CMT1A-REPs evidences two distinct sex-dependent mechanisms and candidate sequences involved in recombination.

The molecular mechanism resulting in the duplication or deletion of a 1.5 Mb region of 17p11.2-p12, associated, respectively, with Charcot-Marie-Tooth type 1A (CMT1A) and hereditary neuropathy with liability to pressure palsies (HNPP), has been proposed to be an unequal crossing-over during meiosis between the two chromosome 17 homologues generated by misalignment of the proximal and distal CMT1A-REP repeats, two homologous sequences flanking the 1.5 Mb CMT1A/HNPP monomer unit. In a recent study of a large series of de novo cases of CMT1A and HNPP, two distinct sex-dependent mechanisms were identified. Rearrangements of paternal origin, essentially duplications, were indeed generated by unequal meiotic crossing-over between the two chromosome 17 homologues, but duplications and deletions of maternal origin resulted from an intrachromosomal process, either unequal sister chromatid exchange or, in the case of deletion, excision of an intrachromatidal loop. In order to determine how these recombinations occur, 24 de novo crossover breakpoints were localized within the 1.7 kb rearrangement hot spot by comparing the sequences of the parental CMT1A-REPs with the chimeric copy in affected offspring. Nineteen out of 21 paternal crossovers were found in a 741 bp hot spot. All the breakpoints of maternal origin (n = 3), however, were located outside this interval, but in closely flanking sequences, supporting the hypothesis that two distinct sex-dependent mechanisms are involved. Several putative recombination promoting sequences in the hot spot, which are rare or absent in the surrounding 7.8 kb, were identified.

Charcot-Marie-Tooth Disease↗

PubMed1998

Surgical management of macular edema.

Macular edema, often a component of diabetic retinopathy, can be complicated by many other diseases. It is considered to be multifactorial and difficult to treat. The relation of the vitreous and macular edema is discussed. We examined many eyes of patients with diabetic macular edema that improved after spontaneous posterior vitreous detachment or vitrectomy for proliferative diabetic retinopathy. Recent advances in vitreous surgery have enabled us to treat surgically eyes with good visual acuity. We began surgical treatment for macular edema without the fibrous membrane in 1990. Here we discuss our experience in surgical treatment of macular edema as contrasted to photocoagulation therapy. This review is based on the published and unpublished results of our cases of more than 100 eyes that underwent vitrectomy for diabetic macular edema.

Diabetic Retinopathy↗

PubMed1998

Long-term effects of zonisamide in the treatment of epilepsy in children with intellectual disability.

Zonisamide is a new drug with broad-spectrum antiepileptic activity against partial as well as generalized seizures. The purpose of the present study was to compare the long-term efficacy of zonisamide in the treatment of epilepsy in children with intellectual disability (ID) with those with normal intelligence (NI). One hundred and thirty children (74 ID, 56 NI) were included in the study. Fifteen of the subjects were eliminated from the study because of adverse effects or aggravation of seizures. The remaining 115 children (66 ID, 49 NI) were followed up for more than one year. Twenty-eight children (6 ID, 22 NI) were in zonisamide monotherapy. The mean numbers of different antiepileptic drugs were 4.5 and 3 for the ID and NI groups, respectively. The overall improvement rates, defined as a >50% reduction in the number of seizures, were 41% (ID) and 67% (NI) (P<0.01). Side-effects were observed in 27% and 30% of subjects in the ID and NI groups, respectively. However, in the monotherapy group, side-effects were observed in 50% (ID) and in 27% (NI). In conclusion, the effectiveness of zonisamide was weaker in children with ID than those with NI. This is in agreement with the known phenomenon that epileptic children with ID are likely have more intractable seizures than those with NI.

Adolescent↗

PubMed1997

Tomaculous neuropathy in Charcot-Marie-Tooth disease with myelin protein zero gene mutation.

Mutation of the myelin protein zero (MPZ) gene is associated with a small number of Charcot-Marie-Tooth (CMT) patients. We present a patient with Lys 130 Arg substitution in the extracellular domain who showed tomacula formation in biopsied sural nerve. CMT patients with mutations Ly 96 Glu, Lys 130 Arg and Ile 135 Leu showed tomaculous neuropathy. Present and previously reported investigations suggest that the pathological phenotypes of peripheral nerve are probably related to the mutations of the MPZ gene.

Amino Acid Substitution↗

PubMed1997

Congenital muscular dystrophy with partial deficiency of merosin.

We present a Japanese patient who has congenital muscular dystrophy, with partial merosin deficiency. The patient had characteristic findings of clinical features and brain MRI. Muscle biopsy showed advanced muscular dystrophy, with greatly reduced muscle fibers and massive infiltration of interstitial connective and fatty tissues. On immunostaining for cytoskeletal proteins, merosin was greatly reduced. The other cytoskeletal proteins, including dystrophin and 50 kDa alpha-sarcoglycan were normally expressed around all muscle fibers.

Child, Preschool↗

PubMed1997

Facilitated diagnosis of CMT1A duplication in chromosome 17p11.2-12: analysis with a CMT1A-REP repeat probe and photostimulated luminescence imaging.

Charcot-Marie-Tooth disease type 1A (CMT1A) is a common autosomal dominant demyelinating peripheral neuropathy. Most patients with CMT1A have been found to have a 1.5 megabase tandem DNA duplication in chromosome 17p11.2-12. Meiotic unequal crossover mediated by the CMT1A-REP repeat is a proposed mechanism for generation of the duplication in CMT1A and a reciprocal deletion seen in hereditary neuropathy with liability to pressure palsies. Testing for the CMT1A duplication is frequently the first step in the molecular diagnosis of patients with suspected inherited demyelinating neuropathy. We used a 1.0 kb EcoRI-PstI DNA fragment (pHK1.0P) from the proximal CMT1A-REP repeat as a probe for Southern blot analysis and detected increased gene dosage in CMT1A by determining measuring radioactivity ratios with a photostimulated luminescence imaging plate. We found that this method is useful for rapid diagnosis of the DNA duplication associated with CMT1A.

Autoradiography↗

PubMed1997

Detection of the CTG repeat expansion in congenital myotonic dystrophy.

Myotonic dystrophy (DM) is caused by an abnormal expansion of an unstable CTG trinucleotide repeat in the 3' untranslated region of mRNA encoding a putative serine/threonine protein kinase. We analyzed 59 patients with DM (28 congenital DM families: 27 families with maternal transmission and 1 paternal transmission) and 27 normal control subjects to evaluate their CTG repeat size between DM patients and the normal controls, and to search for a correlation between the clinical characteristics of congenital DM (CDM) and CTG repeat expansions. Analysis was on the basis of the Southern blot and polymerase chain reaction (PCR) methods, and by direct sequencing of PCR amplified CTG repeats. Analysis of intergenerational differences in the CTG repeat size for mother-child pairs showed a positive correlation (y = 1.0384x + 1265.2, r2 = 0.311). In addition to the strong parental bias, this group showed genetic anticipation. There was a significant correlation of the CTG repeat expansion with disease severity. The largest CTG repeat expansion (2,293 CTG repeats) on average belonged to the severe CDM group, and the smallest (129 CTG repeats) to the subclinical DM group. The mutant allele of an asymptomatic father in the paternally transmitted pedigree revealed 75 CTG repeats, demonstrating that he was a DM protomutation carrier.

Blotting, Southern↗

PubMed1997

Molecular and pathological studies in Charcot-Marie-Tooth disease 1A.

We analyzed a 1.5-Mb duplication of the p11.2-12 region of chromosome 17, including the PMP-22 gene (CMT1A duplication), seven families with Charcot-Marie-Tooth disease type I (CMT I) and six sporadic patients with suspected CMT I by Southern blot analysis. In order to detect the CMT 1A duplication, probe pVAW409R3a, probe PMP-22 cDNA and reference probe SF85 were used for Southern hybridization. In six out of seven families with CMT I, CMT1A duplication was identified. One of six sporadic CMT patients had CMT1A duplication. The probe pVAW4O9R3a was more informative than PMP-22 cDNA and SF85 for detecting CMT1A duplication. In pathological study of biopsied sural nerve, thickened myelin sheath was observed in some myelinated fibers in patients with CMT1A duplication.

Adolescent↗

PubMed1997

Haplotype analysis of congenital myotonic dystrophy patients from asymptomatic DM father.

We report a family with congenital myotonic dystrophy (CDM) transmitted from an asymptomatic DM father; we analyzed the haplotype of this family by using polymorphism within and by flanking the DM protein kinase locus. One patient with congenital DM was homozygous for all markers studied, except for the expanded CTG repeats. Two other patients with congenital DM were heterozygous. One patient with congenital DM who was homozygous had greater clinical severity and more expanded CTG repeats than other CDM patients who were heterozygous. The asymptomatic father had a DM protomutation.

Child↗