Search PubMed⌕ Search

Biomedical subjects

K Iwatsuki

Publications and source records attributed to K Iwatsuki.

At least 127 records · Page 7Linked to original sources
PubMed1993

Phylogenetic relationships of ferns deduced from rbcL gene sequence.

Part of the large subunit of the ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) gene (rbcL) was sequenced from three fern species: Adiantum capillus-veneris, Botrypus strictus, and Osmunda cinnamomea var. fokiensis. This region included 1,333 base pairs, about 90% of the gene. Maximum likelihood analysis of the deduced amino acid sequences indicated that (1) Botrypus (Ophioglossaceae) clustered monophyletically with other ferns (Adiantum, Angiopteris, Osmunda); the closest relative to Botrypus among the three species was Osmunda, which did not support the hypothesis that the Ophioglossaceae are linked to the progymnosperm-seed plant lineage. (2) Eusporangiate ferns containing Botrypus (Ophioglossaceae) and Angiopteris (Marattiaceae) were a paraphyletic group. (3) Seed plants and the four fern species examined formed a monophyletic group, but ferns and bryophytes (liverwort) did not. Variations in rates of substitution for synonymous and nonsynonymous codons were found in fern lineages.

Amino Acid Sequence↗
PubMed1993

Dynamic expression of pemphigus and desmosomal antigens by cultured keratinocytes.

Dynamic expression of pemphigus antigens by cultured human and mouse keratinocytes was compared with that of desmosome-associated molecules and cellular markers relating to epidermal differentiation. Plakoglobin was detected in localized areas of keratinocyte sheets in low Ca2+ (0.15 mM) KGM medium. In minimum essential medium (MEM) containing 1.8 mM Ca2+, plakoglobin was expressed in the intercellular spaces (ICS) throughout the keratinocyte sheet. Desmoplakin I and II, which were present in the cytoplasm of keratinocytes in the low Ca2+ medium, moved to the cell surface after the medium was changed to MEM. Desmoglein 1 and pemphigus vulgaris (PV) antigens were observed in the ICS of both the monolayers and stratified areas in the MEM. Pemphigus foliaceus (PF) antigens, frequently together with desmoglein 1, involucrin and keratins specific for the upper layer of the epidermis, were expressed by stratified keratinocytes but not the cells in the monolayers. The Western blotting study of the cultured keratinocyte extract showed 160- and 130-kDa bands positive for desmoglein 1 antigens and a 130-kDa band stained with PV sera. These findings suggest that although desmoglein 1 molecules bear PF antigenic sites, their expression pattern by cultured keratinocytes is closely related to that of PV rather than PF antigens. The PF antigenic sites may be formed on desmoglein 1 during epidermal differentiation.

Animals↗
PubMed1993

Extramedullary plasmacytoma: cytological and genotypic studies.

A 62-year-old woman had multiple plasmacytomas in the skin and lymph nodes, without Bence-Jones protein or a monoclonal peak of serum immunoglobulins. Infiltrating plasmacytoid cells expressed cytoplasmic IgG (lambda) and surface CD38, without any B-cell markers. There was no visceral or bone marrow involvement suggestive of multiple myeloma. Southern blot analysis of extracted DNA from the cutaneous lesions showed two rearranged bands with an immunoglobulin, but not a T-cell receptor, gene probe. The patient showed a poor response to chemotherapy, and died of bronchopneumonia. The clinical course and cytological features differentiate multiple cutaneous extramedullary plasmacytomas from solitary cutaneous extramedullary plasmacytoma and cutaneous lesions associated with multiple myeloma.

Female↗
PubMed1993

Epidermal antigens and complement-binding anti-intercellular antibodies in pemphigus vegetans, Hallopeau type.

The serum of a 34-year-old woman with the Hallopeau type of pemphigus vegetans (PVg) contained antibodies against a 130-kDa polypeptide in human epidermal lysates, as revealed by Western blot analysis. The serum strongly fixed complement in vitro, and the PVg lesional skin contained a predominance of complement-fixing IgG2 and IgG4. Although the antigens reactive with sera from PVg and pemphigus vulgaris were the same, strong fixation of complement by PVg antibodies, due to the presence of complement-dependent IgG subclasses, and subsequent in situ activation of complement, might explain the marked infiltration of neutrophils and eosinophils in PVg.

Adult↗
PubMed1992

Effects of YM435, a novel dopamine D1 receptor agonist, on pancreatic exocrine secretion in anesthetized dogs.

The effects of YM435, a novel dopamine (DA) D1 receptor agonist, on pancreatic exocrine secretion were investigated in anesthetized dogs. Each drug was injected i.a. as a single bolus. Graded doses of YM435 (0.3-30 nmol) produced dose-dependent increases in the rate of secretion of pancreatic juice, with a maximum effect at approximately 10 nmol, and with a high concentration of bicarbonate and low concentration of protein. SCH23390 (3-30 nmol), a selective D1 receptor antagonist, caused a progressive parallel shift to the right of the dose-response curve for YM435-stimulated pancreatic secretion without changing the maximum response. Schild analysis of the data indicated that the inhibitory constant (Ki) value was 2.9 nmol, and that SCH23390 inhibited YM435-stimulated pancreatic secretion in a competitive manner. Both DA (0.01-3 mumol) and SKF38393 (0.3-30 mumol), a selective D1 receptor agonist, also increased the secretory rate and bicarbonate concentration, and decreased the protein concentration to the same extent as YM435. These results suggest that YM435 is a potent stimulant of pancreatic exocrine secretion by acting on DA D1 receptors of the pancreas in dogs.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1992

Structural rearrangements of the chloroplast genome provide an important phylogenetic link in ferns.

The chloroplast genome of most land plants is highly conserved. In contrast, physical and gene mapping studies have revealed a highly rearranged chloroplast genome in species representing four families of ferns. In all four, there has been a rare duplication of the psbA gene and the order of the psbA, 16S, and 23S rRNA genes has been inverted. Our analysis shows that the described rearrangement results from a minimum of two inversions within the inverted repeat. This chloroplast DNA structure provides unambiguous evidence that phylogenetically links families of ferns once thought to belong to different major evolutionary lineages.

Chloroplasts↗
PubMed1992

TRH regulation of tracheal tension through vagal preganglionic motoneurons.

TRH-immunoreactive nerve terminals innervate the ambiguous nucleus in the rabbit. Vagal preganglionic motoneurons that innervate the trachea, were revealed by HRP histochemistry in the rostral part of the ambiguous nucleus and the dorsal motor nucleus of the vagus. HRP histochemistry plus TRH immunocytochemistry revealed that TRH-immunoreactive axon terminals synapsed on ambiguous nucleus neurons retrogradely labeled by HRP injection into tracheal smooth muscle and the superior laryngeal nerve. Microinjection of 50 ng TRH into the rostral ambiguous nucleus caused slight dilation followed by constriction, which was inhibited by atropine and vagotomy. Results show that central TRH-containing neurons regulate tracheal tension through synapses on vagal preganglionic motoneurons that innervate tracheal smooth muscle.

Animals↗
PubMed1992

Excitation of inspiratory neurons by preinspiratory neurons in rat medulla in vitro.

In brain stem-spinal cord preparations isolated from newborn rats, we examined synaptic connections to inspiratory neurons from preinspiratory (Pre-I) neurons, by spike-triggered averaging. Potentials were simultaneously recorded intracellularly from inspiratory neurons, and extracellularly from Pre-I neurons in the ipsilateral ventrolateral medulla. The Pre-I neuron pulses were used to trigger computer averaging of potential changes. A total of 16 pairs were analyzed, and EPSP-like depolarizing potentials locked to the triggering Pre-I spikes were obtained from three pairs. Latency from the Pre-I spikes was 3.4-4.5 ms, and the amplitude was 0.07-0.4 mV. These connections were concluded to be monosynaptic, because the antidromic latency was 3.6 +/- 1.5 ms. The present results suggest the presence of excitatory synaptic connections from Pre-I neurons to inspiratory neurons in the ventrolateral medulla. These excitatory synaptic connections are probably important in the initiation of inspiratory burst activity.

Animals↗
PubMed1991

Effects of the cyclic nucleotide phosphodiesterase inhibitors, rolipram, 3-isobutyl-1-methylxanthine, amrinone and zaprinast, on pancreatic exocrine secretion in dogs.

The effects of the cyclic phosphodiesterase (PDE) inhibitors, rolipram, 3-isobutyl-1-methylxanthine (IBMX), amrinone and zaprinast on pancreatic exocrine secretion were investigated in anesthetized dogs. Rolipram (1-30 nmol), IBMX (44-440 nmol) or zaprinast (1-10 mumol) injected i.a. elicited a dose-dependent increase in the secretion of pancreatic juice, but amrinone (up to 53 mumol) did not. The bicarbonate concentration in pancreatic juice was increased and the protein concentration was decreased by rolipram and IBMX, but neither was affected by zaprinast. Rolipram elicited more than the respective additive secretory response when added together with secretin, although the stimulatory effects of CCK-8 with rolipram were additive. Rolipram and IBMX, but not zaprinast, increased cyclic AMP concentration but did not affect cyclic GMP concentration. These results suggest that rolipram, IBMX and zaprinast have direct secretory properties on pancreatic exocrine glands of the dog, which may be mediated through the increase of intracellular cyclic AMP concentration, by inhibiting PDE activity. Furthermore, the pancreatic PDE enzyme in the dog pancreas may be mainly a type IV.

1-Methyl-3-isobutylxanthine↗
PubMed1991

Can pemphigus vulgaris become pemphigus foliaceus?

Among 31 patients with pemphigus, we observed two women with clinical and histologic features characteristic of pemphigus vulgaris that later became those of pemphigus foliaceus. Western blot study indicated that serum from one patient, when she had the cutaneous manifestations of pemphigus foliaceus, contained antibodies reactive with a desmosomal antigen, suggestive of desmoglein 1, the same as recognized by pemphigus foliaceus serum. The present study suggests that two distinct types of pemphigus can occur in the same person simultaneously or separately.

Acantholysis↗
PubMed1991

Autoantigens for IgA anti-intercellular antibodies of intercellular IgA vesiculopustular dermatosis.

A new disease characterized by the presence of in vivo bound and/or circulating IgA anti-intercellular (IC) antibodies has recently been identified. We propose the term intercellular IgA vesiculopustular dermatosis (IAVPD) for this entity, which seems to be divided clinicopathologically into at least two distinct subtypes: intraepidermal neutrophilic IgA dermatosis (IEN type) and subcorneal pustular dermatosis-like cases (SPD type). Using immunoblot technique, we examined the antigen substances for the IgA anti-IC antibodies in the sera from one Japanese patient with IEN type of IAVPD and three Japanese patients with SPD type. A serum from a patient with IEN type reacted exclusively with a 120-kD protein in both the normal human skin extract and the bovine desmosome sample. Sera from three patients with SPD type reacted specifically with a doublet of 115-kD and 105-kD proteins, which appeared to be identical to desmocollins I and II, well known desmosomal core proteins, in the bovine desmosome sample. IgA antibody from our patients with IAVPD bound to neither pemphigus vulgaris antigen nor pemphigus foliaceus antigen. From these results, we suggest that IAVPD is different from pemphigus and is heterogeneous in terms of the antigens to which IgA autoantibodies bind.

Autoantibodies↗
PubMed1991

Distinct types of IgG and IgA anti-intercellular autoantibodies from patients with pemphigus and vesiculopustular dermatosis.

The pattern of binding of two different types of IgA class pemphigus-like antibodies was compared with that of the true IgG class pemphigus antibody. The IgG antibodies from pemphigus vulgaris (PV) and pemphigus foliaceus (PF) sera bound to the intercellular spaces in normal human epidermis, whereas only the PV antibody reacted with monolayers of keratinocytes derived from human foreskin. Both IgG and IgA antibodies from a patient with PF were found in the intercellular spaces of the epidermis and only the IgA antibody reacted with the cultured keratinocytes. The IgA antibody from a patient with a vesiculopustular eruption and whose serum contained IgA intercellular space antibody alone, bound to the upper epidermis but not to the monolayers of keratinocytes. These findings indicate that PV but not PF antigens can be expressed by monolayers of cultured human keratinocytes and that there are at least two distinct types of IgA intercellular antibodies.

Autoantibodies↗
PubMed1991

Direct and indirect stimulation of pancreatic exocrine secretion by neurotensin in anaesthetized dogs.

1. The effects of neurotensin on pancreatic exocrine secretion were investigated both in the intact whole pancreas and in the isolated, blood-perfused pancreas ex vivo in anaesthetized dogs. 2. Intravenous (i.v.) injections of neurotensin (0.01-1 nmol/kg) elicited dose-dependent increases in the secretory rate of pancreatic juice without changes in plasma levels of cholecystokinin (CCK). The concentration of bicarbonate in the pancreatic juice induced by neurotensin was increased, but the protein concentration was scarcely changed. 3. The neurotensin-induced secretion was inhibited by SCH23390, a dopamine D-1 antagonist, but not by domperidone, phentolamine, propranolol, atropine, cimetidine, or L-364,718, a CCK antagonist. 4. Intra-arterial (i.a.) injections of neurotensin (0.1-3 nmol/kg) also elicited dose-dependent increases in the secretory rate of pancreatic juice flow, but did not change bicarbonate or protein concentration. The secretory activities were less effective and 1 nmol/kg of neurotensin i.a. was approximately equal to that of 0.03 nmol/kg of neurotensin i.v. 5. These results suggest that neurotensin mainly stimulates pancreatic secretion by acting indirectly. Neurotensin-induced secretion is, at least in part, mediated by endogenously released dopamine which activates dopamine D-1 receptors on the pancreas. In addition to its indirect action, neurotensin has a weak direct action to stimulate pancreatic secretion.

Animals↗
PubMed1991

Ultrastructural binding site of pemphigus foliaceus autoantibodies: comparison with pemphigus vulgaris.

We studied in vivo binding sites of pemphigus foliaceus (PF) autoantibodies by immuno-gold labelling technique, and compared them with those of pemphigus vulgaris (PV). In early acantholytic lesions of PF, the bound antibodies indicated by 5 nm protein A-colloidal gold particles were observed on the surface of keratinocytes, with particular affinity for desmosomes and separated attachment plaques. Nondesmosomal cell surfaces were sparsely labeled with the gold particles. A similar binding pattern was seen in the epidermal sheets obtained from a PV patient utilizing the Nikolsky phenomenon. These findings indicate that both PF and PV antigen-antibody complexes are densely located on the desmosomal areas in early pemphigus lesions, suggesting the pathogenic importance of functional impairment of desmosomes by the autoantibodies.

Aged↗
PubMed1991

Systematized keratotic nevus with finger contracture.

A case of systematized keratotic nevus which is a peculiar form of epidermal nevus is reported. The present case is rare because of the dysfunction of incomplete flexion of fingers by systematized keratotic nevus. Furthermore, it involved mixed clinical and histological changes of epidermal nevus from fingers to elbow. An operation with full-thickness skin graft was undertaken.

Adult↗
PubMed1991

[Localization of HTLV-I-associated antigens in adult T cell leukemia cells and HTLV-I-infected cell line cells].

Localization of HTLV-I-associated antigens was studied in adult T cell leukemia (ATL) cells and HTLV-I-infected cell line cells using monoclonal and human polyclonal antibodies against the viral-related antigens. Two monoclonal antibodies that we obtained by hybridoma technique reacted with HTLV-I-virus core antigens, P19 and P24, respectively. Human anti-HTLV-I-antibodies, which were purified from sera from ATL patients reacted with not only HTLV-I virus particles but also their precursors located in the cytoplasm. In tumor cells freshly isolated from ATL patients, no expression of the virus antigens was observed. When the cells were cultured for several days, the virus antigens were defined in about 3-5% of the cultured cells by the monoclonal antibodies, and in 5-10% by the purified human anti-HTLV-I antibodies. Addition of 5-iodo-2'-deoxyuridine to the culture inhibited cell growth, and at the same time, increased the percentage of the virus antigen-positive cells. Established HTLV-I-infected cell lines showed different cytological profiles from the original ATL cells in the viral replication and morphology.

Antibodies, Monoclonal↗
PubMed1990

Enhanced production of endogenous prostaglandin in obstructive jaundiced pancreas in dogs.

Endogenous pancreatic prostaglandin production in control and obstructive jaundice was investigated using isolated and perfused dog pancreas. In both groups, spontaneous production of prostaglandin E2 and prostaglandin I2 was recorded, and the levels did not change in both groups. The production of both prostaglandins in jaundice, however, was higher than that in the control on stimulation by 8 x 10(-11) mol of cholecystokinin-octapeptide. Amylase release with cholecystokinin-octapeptide at an amount of 8 x 10(-11) mol in jaundice was higher than in the control. The amylase release in both groups, however, showed further elevation on indomethacin pretreatment. On incubation of pancreatic dispersed cells in both groups, prostaglandin production in jaundiced cells was higher than that in control cells. These data showed that enhanced endogenous prostaglandin in obstructive jaundice might be caused by the characteristic change of pancreatic cells, which increased susceptibility to cholecystokinin-octapeptide because of long-term exposure to abnormal blood components, and enhanced prostaglandins might act as a cytoprotector of acinar cells in the pancreas damaged by cholecystokinin-octapeptide administration.

6-Ketoprostaglandin F1 alpha↗