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Biomedical subjects

H Ichikawa

Publications and source records attributed to H Ichikawa.

At least 19 recordsLinked to original sources
PubMed1996

Leukocyte depletion attenuates reperfusion injury in patients with left ventricular hypertrophy.

BACKGROUND: Reperfusion injury can occur after a long period of aortic cross-clamping in patients with left ventricular hypertrophy during open-heart surgery, even with the most up-to-date techniques of myocardial protection. In the present study, we examined whether leukocyte depletion as an adjunct to terminal blood cardioplegia (LDTC) attenuates reperfusion injury in patients with left ventricular hypertrophy (LV mass, >300 g; left ventricular end-systolic volume index, >100 mL/m2) in a group of 30 patients undergoing aortic valve replacement. METHODS AND RESULTS: We used basic cold potassium crystalloid cardioplegic solution. Terminal blood cardioplegic solution (TC) or LDTC was accomplished by mixing a cold potassium crystalloid cardioplegic solution with warm arterial blood obtained through cardiopulmonary bypass and administered to the aortic root for the first 10 minutes of reperfusion. During delivery of LDTC, warm arterial blood was passed through a leukocyte-removal filter. Patients were randomized into one of three groups for reperfusion: whole blood (WB) (n=10), TC (n=10), and LDTC (n=10). Left ventricular biopsies were obtained before ischemia, at the end of ischemia, and 15 minutes after reperfusion. Semiquantitative scoring for ultrastructural alterations indicated that the LDTC group achieved significantly better recoveries of both scores at reperfusion for myocyte damage and for endothelial cell damage of capillaries than did the WB and TC groups. The LDTC group had significantly fewer neutrophils adhering to endothelial cells at reperfusion and a lower level of malondialdehyde derived from myocardium than did the WB and TC groups. Regarding the clinical data, the LDTC group had a lower maximum creatine kinase-MB, a higher percentage of spontaneous defibrillation, a lower pulmonary capillary wedge pressure, and a lower requirement for dopamine that did the WB group, whereas the TC group failed to do better than the WB group. CONCLUSIONS: These results demonstrate that leukocyte-depleted reperfusion is potentially beneficial as an adjunct to terminal cardioplegia during cardiac surgery to attenuate reperfusion injury in patients with left ventricular hypertrophy.

Adult↗
PubMed1996

Two transcripts with different sizes derived from a rice homeobox gene, OSH1.

A rice homeobox gene, OSH1, contains two functionally independent promoters which generate a larger transcript and a smaller transcript. In Arabidopsis, each promoter can drive the expression of a reporter gene in a different manner, indicating that the expression of different sized transcripts is independently regulated by each promoter. Over-expression of the larger transcript in transformed plants caused altered morphologies (Matsuoka et al., Plant Cell, 1993, 5, 1039-1048); in contrast, over-expression of the smaller transcript did not cause any morphological changes. The results suggest that the product of the smaller transcript fails to alter the expression of its target gene(s) in the transformants, while that of the larger transcript is capable of altering the expression of its target gene(s).

Amino Acid Sequence↗
PubMed1996

Calbindin-D28k-immunoreactivity in the trigeminal ganglion neurons and molar tooth pulp of the rat.

The cell body size and coexpression of carbonic anhydrase (CA), calretinin (CR) and calcitonin gene-related peptide (CGRP) of primary neurons with calbindin-D28k (CB) was examined in the trigeminal ganglion (TG) of the rat. CB-immunoreactive (-ir) cells were mostly large and preferentially distributed in the maxillary and mandibular divisions of the TG. 48% of CB-ir TG cells exhibited enzyme CA activity. 10% of CB-ir TG cells contained CR-ir. Most TG cells coexpressing CB- and CR-irs were localized to the maxillary and mandibular divisions and exhibited CA activity. 6.5% of CB-ir TG cells coexisted with CGRP-ir. 46% of TG cells coexpressing CB and CGRP exhibited CA activity. The innervation of the molar tooth pulp by CB-ir TG primary neurons was also examined. CB-ir thick and smooth nerve fibers projected from the root pulp to the pulp horn and the roof of the pulp chamber, where they became thinner and rarely entered the subodontoblastic layer. However, they could not be traced to the odontoblastic layer, predentin or dentine. The distribution pattern of CB-ir pulpal fibers was different from that of CR-ir ones. The trigeminal neurons cells retrogradely labeled with fast blue (FB) from the maxillary molar tooth pulp contained CB- and CR-irs. 23% and 1% of the labeled cells were immunoreactive for CB and CR, respectively. The coexpression of CB- and CR-immunoreactivities (-irs) in FB-labeled cells was negligible. An immunoelectron microscopic method revealed that 21% of pulpal nerve fibers were immunoreactive for CB, and that all CB-ir nerve fibers in the root pulp were myelinated. The present study indicated that the tooth pulp primary neurons contained CB-ir but did not coexpress CB- and CR-irs and that these neurons projected their myelinated axons to the pulp.

Animals↗
PubMed1996

A 1.6-Mb P1-based physical map of the Down syndrome region on chromosome 21.

The Down syndrome (DS) region on chromosome 21, which is responsible for the main features of DS such as characteristic facial features, a congenital heart defect, and mental retardation, has been defined by molecular analysis of DS patients with partial trisomy 21. The 2. 5-Mb region around the marker D21S55 between D21S17 and ERG in 21q22 is thought to be important, although contributions of other regions cannot be excluded. In this region, we focused on a 1.6-Mb region between a NotI site, LA68 (D21S396, which is mapped distal to D21S17) and ERG, because analysis of a Japanese DS family with partial trisomy 21 revealed that the proximal border of its triplicated region was distal to LA68. We constructed P1 contigs with 46 P1 clones covering more than 95% of the 1.6-Mb region. A high-resolution restriction map using BamHI was also constructed for more detailed analysis. Our P1 contig map supplements other physical maps previously reported and provides useful materials for further analysis including gene isolation and sequencing of the DS region.

Base Sequence↗
PubMed1996

Identification of a novel human gene containing the tetratricopeptide repeat domain from the Down syndrome region of chromosome 21.

The Down syndrome (DS) region on chromosome 21, which is responsible for the DS main features, has been defined by analysis of DS patients with partial trisomy 21. Within the DS region, we constructed a 1.6-Mb P1 contig map previously. To isolate gene fragments from the 1.6-Mb region, we performed direct cDNA library screening and exon trapping using the P1 clones and a human fetal brain cDNA library, and obtained 67 cDNA fragments and 52 possible exons. Among them, 23 cDNA fragments and 4 exons were interpreted to be derived from a single gene by localization on P1 clones and by Northern analysis. To obtain the full-length cDNA sequence, longer cDNA clones were further screened from another human cDNA library which was enriched with longer cDNA species. These clones were sequenced and assembled to a sequence of 9045 bp. This transcribed sequence encodes a novel 2025 amino-acid protein containing tetratricopeptide repeat (TPR) motifs and therefore the gene was designated as TPRD (a gene containing the TPR motifs on the Down syndrome region). The TPR domain has been found in a certain protein phosphatase and in other proteins involved in the regulation of RNA synthesis or mitosis. The TPRD gene, the novel gene which was proved to be in the 1.6-Mb region and to have the interesting features described above, is a candidate for genes responsible for the DS phenotypes.

Amino Acid Sequence↗
PubMed1996

Transient reperfusion with acidic solution affects postischemic functional recovery: studies in the isolated working rat heart.

This isolated working rat heart study was designed to investigate the effect of duration of reperfusion and degree of acidity of the reperfusate on myocardial protection. The experimental time course was as follows: 20 minutes of perfusion with the heart working, 3 minutes of infusion with the St. Thomas' Hospital cardioplegic solution followed by global ischemia for 33 minutes at 37 degrees C, and 20 minutes of Langendorff reperfusion followed by 20 minutes of working perfusion. During the initial 3 minutes of Langendorff reperfusion, the pH of the reperfusate was changed to 5.6, 6.8, and 7.5 by addition of sodium hydroxide into Krebs-Henseleit nonbicarbonate HEPES buffer. A respiratory acidic reperfusate was used for the initial 0.5, 1, 2, 3, 5, and 15 minutes during reperfusion. The results were as follows: (1) Reperfusion with a mildly acidic solution (i.e., pH 6.8) yielded better recovery than reperfusion with solutions having pH levels of 5.8 or 7.5. (2) Reperfusion for less than 3 minutes with a reperfusate having a pH level of 6.8 provided better recovery, although reperfusion for longer than 3 minutes exacerbated reperfusion injury. In conclusion, the effects of reperfusion with acidic solution were influenced by degree and duration with biphasic response characteristics.

Analysis of Variance↗
PubMed1996

Myocardial troponin T levels in patients with diabetic nephropathy.

We investigated myocardial troponin T (TnT) level as a marker for myocardial injury at various stages of diabetic nephropathy, including end-stage renal failure. One hundred and four diabetic patients were included in this study. These patients were divided into 5 groups as follows: Group I, composed of 41 patients without nephropathy who served as controls; Group II, composed of 15 patients with micro-albuminuria; Group III, composed of 15 patients with macroalbuminuria; Group IV, composed of 8 patients with renal failure who were not receiving hemodialysis; and Group V, composed of 25 patients who were receiving hemodialysis for renal failure. The following markers of myocardial injury were measured in these patients: myocardial TnT, creatine kinase (CK), myoglobin (Mb), and myosin light chain-1 (MCL-1). Our results showed that as the disease state of diabetic nephropathy advanced to renal failure, myocardial TnT levels became elevated. Group V showed significantly higher myocardial TnT levels than either Group I, Group II or Group III. Group IV showed significantly higher myocardial TnT levels than either Group II or Group III. The rate of ischemic changes on electrocardiograms also tended to increase with advance to renal failure in these patients. However, there was no correlation between myocardial TnT levels and serum Cr levels, used as an index for renal function. Myocardial TnT levels had a higher specificity for cardiac muscle than other markers for myocardial injury and are not significantly influenced by renal function. Myocardial TnT may be useful as a marker of myocardial injury for patients with chronic renal failure.

Adult↗
PubMed1996

[Left ventricular rupture following aortic and mitral valve replacement in a patient with osteogenesis imperfecta: a case report].

Intraoperative left ventricular rupture (type I) occurred following aortic and mitral valve replacement in 62-year-old man with osteogenesis imperfecta. Re-replacement of the mitral valve and the repair of left ventricular rupture were successfully performed. However, the patient died suddenly 3 days after the operation. Retroperitoneal bleeding due to the insertion of a continuous hemofiltration catheter via the femoral vein was detected at autopsy. Seven patients who underwent double valve replacements for aortic and mitral disease with osteogenesis imperfecta were reported with poor surgical results. We report our patient and discuss the relationship between osteogenesis imperfecta and left ventricular rupture.

Aortic Valve↗
PubMed1996

Plasma concentrations of natriuretic peptides in patients on hemodialysis.

The usefulness of plasma atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and cyclic guanosine 3',5'- monophosphate (cGMP) as markers of fluid overload was examined in hemodialysis (HD) patients without diabetes mellitus. Plasma concentrations of ANP, BNP, CNP, and cGMP all decreased significantly during HD. Before HD, there was a strong correlation between plasma concentrations of ANP and those of BNP, and plasma concentrations of cGMP correlated significantly with those of all three natriuretic peptides. The cardiothoracic ratio also correlated significantly with plasma concentrations of ANP and those of BNP before HD. Systolic blood pressure correlated significantly only with plasma concentrations of CNP, both before and after HD. Changes in body weight during HD correlated only with those in plasma ANP; there was thus no correlation between changes in body weight and those in plasma CNP. In conclusion, only plasma ANP is a useful marker of the proper volume and dry weight of HD patients. Furthermore, CNP may participate in cardiovascular regulation in HD patients in a manner different from those of ANP and BNP.

Adult↗
PubMed1995

Assignment of the E4TF1-60 gene to human chromosome 21q21.2-q21.3.

The gene encoding human transcription factor E4TF1-60 was previously mapped to chromosome 21q21. We analyzed the localization of the E4TF1-60 gene in more detail by genomic Southern hybridization and determined the sequence of the exons and the regions surrounding the intron boundaries. We report here that E4TF1-60 locates in the long arm of chromosome 21 at q21.2-q21.3 and contains a total of ten exons.

Chromosomes, Artificial, Yeast↗
PubMed1995

Localization of cDNAs to a region poorly represented in the CEPH chromosome 21 YAC contig: candidate genes for genetic diseases mapped to 21q22.3.

Fifty-three cDNA fragments previously obtained by hybridization selection from random clones in the chromosome 21 cosmid library LL21CNO2 failed to identify clones in the chromosome 21 YAC contig described by Chumakov et al. (1992, Nature 359: 380-387). Using an expanded panel of somatic cell hybrids, we have verified that the majority of these cDNAs map to chromosome 21 and that in particular a very high proportion, approximately 85%, localize to a 5-Mb region of distal 21q22.3. Pulsed-field analysis coupled with information from the NotI restriction map of the region further indicate that 17 cDNA fragments map within 650 kb of the PFKL gene and thus may be candidates for genetic diseases linked to this gene. This work helps to characterize a region poorly represented in the CEPH YAC contig and adds to the number of cDNAs useful in analysis of chromosome 21-associated diseases.

Animals↗
PubMed1995

Parvalbumin- and calretinin-immunoreactive trigeminal neurons innervating the rat molar tooth pulp.

Calcium-binding proteins and neuropeptides were examined in trigeminal neuronal cell bodies retrogradely labeled with Fast blue (FB) from the maxillary molar tooth pulp of the rat. FB-labeled cells were located in the maxillary division of the trigeminal ganglion. Approximately 30 and 50% of the labeled cells were immunoreactive for parvalbumin and calcitonin gene-related peptide (CGRP), respectively. The coexpression of these substances was observed in 9.5% of FB-labeled cells. On the other hand, 2.4% of FB-labeled cells exhibited calretinin-immunoreactivity (CR-ir) and 20% tachykinin (TK)-ir. The coexpression of CR and TK was observed in 1.9% of FB-labeled cells, i.e., most of CR-ir FB-labeled neurons coexpressed TK-ir. An immuno-EM method revealed that all parvalbumin-ir nerve fibers in the root pulp were myelinated and that CGRP-ir nerve fibers were both myelinated (15%) and unmyelinated (85%). The present study indicated that primary nociceptors innervating the rat molar tooth pulp contained parvalbumin and CR and coexpressed these calcium-binding proteins and neuropeptides. It was suggested that peripheral axons of parvalbumin-ir tooth pulp primary neurons are all myelinated. Most peripheral CR-ir axons are probably unmyelinated because TK-ir myelinated axons have never been demonstrated in any peripheral organ.

Animals↗
PubMed1995

CGRP in peripherally axotomized mesencephalic trigeminal neurones of the rat.

Immunoreactivities for substance P (SP-ir) and calcitonin gene-related peptide (CGRP-ir) were examined in neurones in the mesencephalic trigeminal tract nucleus of nerve-injured rats. One week following unilateral transection of the trigeminal root, the masseteric nerve (MN) or the inferior alveolar nerve (IAN), CGRP-ir but not SP-ir was detected in these neurones bilaterally with ipsilateral dominance. Most of the CGRP-ir (immunoreactive) neurones were retrogradely labelled when fluorogold (FG) had been applied to the proximal stump of the MN or the IAN. Sham surgery including insult to the masseter muscle induced CGRP-ir while skin incision did not.

Animals↗
PubMed1995

Parvalbumin and calbindin D-28k in vagal and glossopharyngeal sensory neurons of the rat.

Parvalbumin- and calbindin D-28k-immunoreactivities (ir) were examined in the glossopharyngeal and vagal sensory ganglia (petrosal, nodose and jugular ganglia), the carotid sinus nerve and the carotid body. Parvalbumin-ir nerve cells were mostly localized in the petrosal and nodose ganglia and were rare in the jugular ganglion. Calbindin D-28k-ir nerve cells were found in moderate and large numbers in the petrosal and nodose ganglia, respectively. Only a few calbindin D-28k-ir nerve cells were observed in the jugular ganglion. The carotid sinus nerve and carotid body contained numerous calbindin D-28k-ir nerve fibers but few parvalbumin-ir nerve fibers. Studies of the coexistence of these calcium-binding proteins with calcitonin gene-related peptide (CGRP)- and tyrosine hydroxylase (TH)-ir showed that CGRP-ir was rarely colocalized in parvalbumin- or calbindin D-28k-ir nerve cells in the petrosal or nodose ganglion. Moreover, TH-ir was not generally contained in parvalbumin-ir nerve cells in the petrosal, nodose and jugular ganglia while a portion (15-19%) of calbindin D-28k-ir neurons in the petrosal and nodose ganglia colocalized TH-ir. These findings are consistent with the involvement of calcium-binding proteins, particularly calbindin D-28k, in the function of visceral sensory neural systems of the glossopharyngeal and vagus nerves and, perhaps, in baro- and chemoreceptor neurotransmission.

Animals↗
PubMed1995

YAC analysis and minimal tiling path construction for chromosome 21q.

We have undertaken a detailed analysis of several hundred YACs from widely available YAC libraries which map to human chromosome 21 with the goal of improving the physical map of chromosome 21 and determining the feasibility of producing a minimal tiling path of well characterized, stable, non-chimeric YACs spanning the long arm of the chromosome (21q). We report information on over 500 YACs known to contain STS from 21q including information on size, stability, chimerism, marker content, and NotI restriction sites. YACs derive from the CEPH and St. Louis YAC libraries, and STSs include the set of 198 markers originally used do assemble a YAC contig of 21q, as well as additional anonymous probes and gene markers. This information has assisted in refinements of STS order, has defined a region of general instability in 2lq22.3, has identified an increased number of NotI restriction sites, and has defined cryptic gaps, particularly in 2lq2l, for which few or no markers are available. These results have allowed us to develop and assess a minimal tiling path of overlapping YACs consisting of 59 YACs (and two PI clones), largely non chimeric, stable, and of verified STS content. They total 30 mb of non-overlapping DNA, and contain all chromosome 21 specific STSs originally used to define the 810 YAC 21q YAC contig. When integrated with the analysis of a somatic cell hybrid mapping panel of chromosome 21 reported in the accompanying manuscript, a greatly enhanced understanding of the physical map of chromosome 21 is obtained.

Chromosome Mapping↗