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Biomedical subjects

R Tamura

Publications and source records attributed to R Tamura.

At least 73 records · Page 4Linked to original sources
PubMed1996

Coexistence of calcitonin gene-related peptide- and substance P-like immunoreactivity in retrogradely labeled superior spermatic neurons in the dog.

The coexistence of calcitonin gene-related peptide (CGRP) and substance P (SP) was determined in primary afferent neurons of the superior spermatic nerve of the dog. Testicular afferent neurons were visualized by retrograde labeling with the fluorescent dye fast blue. CGRP-like immunoreactivity (LI) was found in about 80% of testicular L1 and L2 dorsal root ganglion cells, and 81% of CGRP-positive neurons also contained SP. Conversely, SP-LI was found in 66% of testicular afferents, and 96% of SP-positive neurons simultaneously contained CGRP. Both CGRP- and SP-LI were observed in the whole size range of the testicular afferent neurons. No significant difference in the diameter was detected between CGRP- and SP-positive testicular afferent neurons. In contrast, the diameter of SP-positive cells was significantly smaller than that of CGRP-positive cells in the whole population of dorsal root ganglion (DRG) neurons. Compared to skin and muscle afferents, a larger population of the testicular afferents contain these peptides. This is considered to be one of the characteristic features of visceral afferents. Coexistence of CGRP and SP in testicular afferent neurons suggest a close functional relationship between these two neuropeptides in the sensory nervous system.

Amidines↗
PubMed1996

[Effect of timing of granulocyte-colony stimulating factor administration on leukopenia induced by systemic chemotherapy in patients with non-small-cell lung cancer--multi-center randomized crossover study].

Sixty-six chemotherapy-naive patients with non-small-cell carcinoma of the lung were given two courses of systemic chemotherapy consisting of mitomycin C, vindesine, and cisplatin. The effect of the timing of administration of grannulocyte colony-stimulating factor (G-CSF) on the incidence of neutropenic fever, the nadir leukocyte count, the duration of neutropenia ( < or = 1000/mm3), and the time needed for recovery from neutropenia was studied. Patients were assigned at random to begin receiving G-CSF (50 microns/m2, subcutaneously) either when the leukocyte count was less than or equal to 1000/mm3 (group I) or when it was between 1000/mm3 and 2000/mm3 (group II), in a crossover fashion. The nadir leukocyte count was lower in group I than in group II (859/mm3 and 1215/mm3, respectively). The duration of leukopenia (defined as a leukocyte count less than or equal to 1000/mm3) was greater in group I than in group II (1.5 days and 0.8 day, respectively), as was the time needed for recovery to a leukocyte count of 2000/mm3 (1.9 days and 1.6 days, respectively) (p < 0.05). No differences were found in the incidence of neutropenic fever (group I: 44%, group Ii: 45%), in the duration of fever (group I: 2.3 days, group II: 2.8 days), or in the duration of G-CSF use (group I: 6.3 days, group II: 6.8 days). There were no treatment-related deaths in either group. We conclude that when this type of combination chemotherapy is given for non-small-cell carcinoma of the lung, administration of G-CSF can be postponed without clinical problems until the leukocyte count is less than of equal to 1000/mm3.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

[An elderly patient with gastric cancer surviving long after chemotherapy using UFT alone].

A 77-year-old patient with low activity of daily life (ADL) having advanced gastric cancer was treated by low dose UFT alone (300 mg/day) for more than 11 years. He survived, and neither remarkable progression nor metastasis of the gastric cancer has been observed in more than an 11-year hospital-free survival period. He has maintained his low ADL, and no side effects of the chemotherapy were observed. This case is probably rare, but suggestive in the choice of treatment for elderly patients.

Activities of Daily Living↗
PubMed1995

A splice variant of alpha 6 integrin is associated with malignant conversion in mouse skin tumorigenesis.

The epithelial-specific integrin alpha 6 beta 4 is suprabasally expressed in benign skin tumors (papillomas) and is diffusely expressed in carcinomas associated with an increase in the proliferating compartment. Analysis of RNA samples by reverse transcriptase-PCR and DNA sequencing revealed that chemically or oncogenically induced papillomas (n = 8) expressed a single transcript of the alpha 6 subunit, identified as the alpha 6 A splice variant. In contrast, carcinomas (n = 13) expressed both alpha 6A and an alternatively spliced form, alpha 6B. Primary keratinocytes and a number of keratinocyte cell lines that vary in biological potential from normal skin, to benign papillomas, to well-differentiated slowly growing carcinomas exclusively expressed alpha 6A. However, I7, an oncogene-induced cell line that produces highly invasive carcinomas, expressed both alpha 6A and alpha 6B transcript and protein. The expression of alpha 6B in I7 cells was associated with increased attachment to a laminin matrix compared to cell lines exclusively expressing alpha 6A. Furthermore, introduction of an alpha 6B expression vector into a papilloma cell line expressing alpha 6A increased laminin attachment. When a papilloma cell line was converted to an invasive carcinoma by introduction of the v-fos oncogene, the malignant cells expressed both alpha 6A and alpha 6B, while the parent cell line and cells transduced with v-jun or c-myc, which retained the papilloma phenotype, expressed only alpha 6A. Comparative analysis of alpha 6B expression in cell lines and their derived tumors indicate that alpha 6B transcripts are more abundant in tumors than cell lines, and alpha 6B is expressed to a greater extent in poorly differentiated tumors. These results establish a link between malignant conversion and invasion of squamous tumor cells and the regulation of transcript processing of the alpha 6 beta 4 integrin.

Alternative Splicing↗
PubMed1995

Central motor reorganization after anastomosis of the musculocutaneous and intercostal nerves following cervical root avulsion.

In 4 patients with a complete upper limb palsy due to traumatic cervical root avulsion, surgical anastomosis of intercostal to musculocutaneous nerves was performed to restore function in the biceps brachii muscle. Four to 6 months after the operation, motor unit discharges were recorded from the biceps muscle on the operated side during deep breathing and by cortical magnetic stimulation. The motor unit discharges became independent from respirations gradually over 1 to 2 years. The latencies of the motor potentials evoked by cortical and thoracic root magnetic stimulation decreased gradually over 2 to 3 years. Motor cortex mapping of the reinnervated biceps muscle showed a gradual change over 4 to 33 months from the area of the intercostal muscles to that of the arm area, which was more lateral on the motor cortex. These findings suggest that reorganization of the motor cortex to arm flexor muscles occurs following peripheral nerve anastomosis.

Accidents, Traffic↗
PubMed1995

Isolated hyperechoic fetal bowel: significance and implications for management.

OBJECTIVE: The objective of this study was to determine the significance of isolated hyperechoic fetal bowel. STUDY DESIGN: Forty-five cases with prospective, ultrasonographic diagnosis of isolated hyperechoic fetal bowel were reviewed. Fetal variables, including aneuploidy, deoxyribonucleic acid studies for cystic fibrosis, congenital infection, growth retardation, and intrauterine death were reported. RESULTS: Thirty-four of the 45 cases (76%) resulted in live-born infants without detected abnormalities. However, hyperechoic bowel was associated with cystic fibrosis in two cases (4%), congenital infection in two cases (4%), and fetal alcohol syndrome in one case. Termination of pregnancy was elected in three cases and intrauterine fetal death occurred in three cases (7%). Growth retardation was observed in five of 39 (13%) live-born infants. CONCLUSION: Isolated hyperechoic fetal bowel is associated with significant pathologic disorders. Women whose fetuses are diagnosed as having isolated hyperechoic bowel should be offered additional prenatal diagnostic options, including maternal serologic studies for congenital infection, fetal karyotype, and deoxyribonucleic acid testing for cystic fibrosis. In addition, continuing ultrasonographic evaluation of fetal growth and antenatal biophysical assessment should be considered.

Cystic Fibrosis↗
PubMed1995

Neuronal responsiveness to various sensory stimuli, and associative learning in the rat amygdala.

Neuronal activities were recorded from the amygdala and amygdalostriatal transition area of behaving rats during discrimination of conditioned auditory, visual, olfactory, and somatosensory stimuli associated with positive and/or negative reinforcements. Neurons were also tested with taste solution and various sensory stimuli that were not associated with reinforcement. Of the 1195 neurons tested, 475 responded to one or more sensory stimuli. Of these, 256 neurons responded exclusively to a unimodal sensory stimulus, 128 to multimodal sensory stimuli, and the remaining 91 could not be classified. Distribution of unimodal neurons was correlated with anatomical projections to the amygdala from sensory thalamus or sensory cortices. Multimodal neurons were located mainly in the basolateral and central nuclei of the amgydala. Response latencies of neurons in the basolateral nucleus were longer than those in other nuclei and neurons in the central nucleus had both short and long latencies. Neurons responsive to a given stimulus were more frequently encountered in the amygdalas of the trained rats than in those of the rats not trained to associate that stimulus with a reinforcement. Multimodal neurons that responded to conditioned and/or unconditioned stimuli used in the associative learned tasks were concentrated in the basolateral and central nuclei. The results indicate that some amygdalar neurons receive exclusive single sensory information, and the others receive information from two or more sensory inputs. Considering the long latencies and multimodal responsiveness, the basolateral and central nuclei of the amygdala might be foci where various kinds of sensory information converge. It is also suggested that the basolateral and central nuclei of the amygdala have critical roles in associative learning to relate sensory information to reinforcement or affective significance.

Acoustic Stimulation↗
PubMed1995

Enhanced migration of fibroblasts derived from lungs with fibrotic lesions.

BACKGROUND: The migration and proliferation of fibroblasts may be important in the pathogenesis of pulmonary fibrosis. Considerable data are available on the proliferation of fibroblasts, but very few on their migration. METHODS: The migratory activity of fibroblasts obtained from lung biopsy specimens from 11 patients with idiopathic pulmonary fibrosis (IPF) was studied using a 96-well chemotaxis chamber. Fibroblasts from eight normal controls, seven patients with interstitial fibrosis associated with a collagen vascular disease (IP-CVD), and 13 patients with sarcoidosis were also examined. Migratory activity was tested in a serum-free medium in the presence and absence of platelet derived growth factor (PDGF), 30 ng/ml, as a chemoattractant. RESULTS: Migration of fibroblasts from patients with IPF was enhanced in serum-free maintenance medium alone (mean (SD) controls v IPF: 183 (86) v 689 (491) cells/field), and was also enhanced when cells were stimulated by PDGF (controls v IPF: 829 (222) v 1928 (600) cells/field). Fibroblasts from tissues with dense fibrosis had a greater capacity for migration than those from an earlier stage of fibrosis. No correlation was found between migratory activity and proliferative capacity of the individual cells. CONCLUSIONS: The fact that fibroblasts from fibrotic lungs migrate faster than those from controls suggests that migration is related to the initiation of the pulmonary fibrotic process. These in vitro studies suggest that fibroblasts derived from the lungs of patients with pulmonary fibrosis have a migratory phenotype. Such a change in fibroblast phenotype, if it occurred in vivo, may be important in the context of the pathogenesis of pulmonary fibrosis.

Adult↗
PubMed1995

[Two cases of intrapulmonary lymph node associated with either progressive systemic sclerosis or idiopathic pulmonary fibrosis].

We encountered 2 cases of intrapulmonary lymph node. Case 1 was in a 48-year-old woman who had been given a diagnosis of progressive systemic sclerosis. Case 2 was in a 49-year-old woman with idiopathic pulmonary fibrosis. In each patient, a follow-up chest CT scan showed a pulmonary nodule, which could not be seen on chest X-ray film. Each nodule has an irregular margin and a linear shadow resembling pleural indentation. Histological examination of the open biopsy specimens revealed that these nodules were intrapulmonary lymph nodes surrounded by interstitial pneumonia. Previous case reports and these 2 cases indicate that unless a thoracotomy is done intrapulmonary lymph nodes are difficult to distinguish from lung cancers.

Diagnosis, Differential↗
PubMed1994

Norepinephrine excitation of cutaneous nociceptors in adjuvant-induced inflamed rats does not depend on sympathetic neurons.

To test the contribution of sympathetic postganglionic neurons (SPGNs) to adrenergic excitation of cutaneous nociceptor activities in adjuvant-inflamed rats (AI rats), we studied the effects of norepinephrine (NE) in a group of sympathectomized AI rats. Sympathectomy was complete in 4-6 weeks by guanethidine (30-50 mg/kg). NE excited polymodal receptor units in the saphenous nerve at an incidence (25-30%) similar to that in AI rats, while CH-38083 blocked such excitation. These results show that alpha 2-adrenoceptors in SPGNs are not involved in the norepinephrine excitation of cutaneous nociceptors in AI rats.

Adrenergic alpha-Antagonists↗
PubMed1994

Arteriovenous malformation of the uterus associated with a missed abortion.

Arteriovenous malformation of the uterus is a rare uterine abnormality. This entity is generally associated with the presence of molar disease, choriocarcinoma and uterine surgery, but may be congenitally acquired. The presence of an arteriovenous malformation generally leads to unexplained profuse uterine bleeding. The diagnosis of this entity has traditionally been made by arteriography, and the treatment is usually hysterectomy. We present a patient with an arteriovenous malformation of the uterus whose prior delivery was by Cesarean section. The patient experienced episodes of heavy vaginal bleeding in the first month following the procedure of suction curettage for a first-trimester pregnancy loss. Chorionic villus sampling performed prior to the procedure showed a chromosomally normal fetus. The diagnosis of an arteriovenous malformation was made by color Doppler velocimetry and confirmed with arteriography. The patient desired to maintain her fertility. Interventional radiological techniques were successfully utilized to obliterate the arteriovenous malformation with the use of polyvinyl alcohol particles (250 micro m) and gelfoam. Discussion includes the presenting signs and symptoms along with the method of both diagnosis and conservative management.

Journal Article↗
PubMed1994

A monoclonal antibody inhibits adhesion to fibronectin and vitronectin of a colon carcinoma cell line and recognizes the integrins alpha v beta 3, alpha v beta 5, and alpha v beta 6.

Using whole viable human colon carcinoma HT29 cells as immunogen, we produced a monoclonal antibody (mAb) termed 69-6-5. The antibody was functionally selected on its anti-cell-spreading activity. By immunoprecipitation of surface radiolabeled cell lysates from HT29-D4 cells (an HT29 cell clone), mAb 69-6-5 recognized a molecular complex resembling integrin heterodimers. Sequential immunodepletions with mAb to the integrin alpha v subunit demonstrated that this complex was composed of alpha v-containing integrins. Accordingly, mAb 69-6-5 reacted with integrin alpha v beta 3 immunopurified from melanoma cells and integrins alpha v beta 5 and alpha v beta 6 immunopurified from pancreatic carcinoma cells. In cell adhesion assays, the 69-6-5 mAb was able to inhibit strongly in a dose-dependent manner arginine-glycine-aspartic acid-mediated adhesion of HT29-D4 cells to vitronectin, fibronectin, or ProNectin F but not to laminin or collagen. Immunoprecipitations with beta chain-specific antisera indicated that these cells express integrins alpha v beta 5 (receptor for vitronectin) and alpha v beta 6 (receptor for fibronectin) but neither alpha v beta 1 nor alpha v beta 3. In summary, these results indicated that mAb 69-6-5 reacts with several alpha v integrins and that it can effectively interfere with the adhesive functions of at least alpha v beta 5 and alpha v beta 6, which represent the major receptors on HT29-D4 cells responsible for their adhesion on vitronectin and fibronectin.

Amino Acid Sequence↗
PubMed1994

Integrin cytoplasmic domains mediate inside-out signal transduction.

We analyzed the binding of fibronectin to integrin alpha 5 beta 1 in various cells; in some cells fibronectin bound with low affinity (e.g., K562 cells) whereas in others (e.g., CHO), it bound with high affinity (Kd approximately 100 nM) in an energy-dependent manner. We constructed chimeras of the extracellular and transmembrane domains of alpha IIb beta 3 joined to the cytoplasmic domains of alpha 5 beta 1. The affinity state of these chimeras was assessed by binding of fibrinogen or the monoclonal antibody, PAC1. The cytoplasmic domains of alpha 5 beta 1 conferred an energy-dependent high affinity state on alpha IIb beta 3 in CHO but not K562 cells. Three additional alpha cytoplasmic domains (alpha 2, alpha 6A, alpha 6B) conferred PAC1 binding in CHO cells, while three others (alpha M, alpha L, alpha v) did not. In the high affinity alpha chimeras, cotransfection with a truncated (beta 3 delta 724) or mutated (beta 3(S752-->P)) beta 3 subunit abolished high affinity binding. Thus, both cytoplasmic domains are required for energy-dependent, cell type-specific affinity modulation. In addition, mutations that disrupted a highly conserved alpha subunit GFFKR motif, resulted in high affinity binding of ligands to alpha IIb beta 3. In contrast to the chimeras, the high affinity state of these mutants was independent of cellular metabolism, cell type, and the bulk of the beta subunit cytoplasmic domain. Thus, integrin cytoplasmic domains mediate inside-out signaling. Furthermore, the highly conserved GFFKR motif of the alpha subunit cytoplasmic domain maintains the default low affinity state.

Amino Acid Sequence↗