Biomedical subjects

T Kamo

Publications and source records attributed to T Kamo.

At least 19 recordsLinked to original sources

PubMed2001

Mechanisms of hypotensive effects of a posture change from seated to supine in humans.

The hypothesis tested was that the hydrostatic stimulation of carotid baroreceptors is pivotal to decrease mean arterial pressure at heart level during a posture change from seated to supine. In eight males, the cardiovascular responses to a 15-min posture change from seated to supine were compared with those of water immersion to the xiphoid process and to the neck, respectively. Left atrial diameter and cardiac output (rebreathing) increased similarly during the posture change and water immersion to the xiphoid process and further so during neck immersion. Mean arterial pressure decreased by 12 +/- 2 mmHg during the posture change, by 5 +/- 1 mmHg during xiphoid immersion, and was unchanged during neck immersion. Arterial pulse pressure increased by 12 +/- 3 mmHg during the posture change (P < 0.05) and less during xiphoid and neck immersion by 7 +/- 3 mmHg (P < 0.05). Total peripheral vascular resistance decreased similarly during the posture change and neck immersion and slightly less during xiphoid immersion (P < 0.05). In conclusion, the hydrostatic stimulation of carotid baroreceptors combined with some additional increase in arterial pulse pressure, which also stimulates aortic baroreceptors, accounts for more than half of the hypotensive response at heart level to a posture change from seated to supine.

Adult↗

PubMed2001

Aspirin enhances the induction of type I allergic symptoms when combined with food and exercise in patients with food-dependent exercise-induced anaphylaxis.

We examined the effect of aspirin as a substitute for exercise in inducing urticaria/anaphylaxis in three patients with food-dependent exercise-induced anaphylaxis (FDEIA). Two of the patients had specific IgE antibodies to wheat and the other had antibodies to shrimp. Administration of aspirin before ingestion of food allergens induced urticaria in one patient and urticaria and hypotension in another, while aspirin alone or food alone elicited no response. The third patient developed urticaria only when he took all three items, i.e. aspirin, food and additional exercise, whereas provocation with any one or or two of these did not induce any symptoms. These findings suggest that aspirin upregulates type I allergic responses to food in patients with FDEIA, and further shows that aspirin synergizes with exercise to provoke symptoms of FDEIA. This is the first report of a synergistic effect of aspirin in inducing urticaria/anaphylaxis, which was confirmed using challenge tests in patients with FDEIA.

Adolescent↗

PubMed2001

PCR-based method for isolation and detection of Chlamydia pneumoniae DNA in cerebrospinal fluids.

Since current studies indicate the possible involvement of Chlamydia pneumoniae in the pathogenesis of multiple sclerosis (MS), demonstration of C. pneumoniae in the cerebrospinal fluid (CSF) of patients with MS is highly desirable. However, there is controversy concerning the detection of C. pneumoniae in CSFs from MS patients due to the lack of a standard protocol for extraction and detection of C. pneumoniae DNA. In this regard, we attempted to establish a highly effective extraction protocol for C. pneumoniae DNA from CSFs utilizing a commercial kit and a PCR detection method. The extraction and PCR detection protocol established in this study succeeded in detecting as few as 20 C. pneumoniae organisms in 200 microl of mock CSF. The use of this protocol to detect C. pneumoniae DNA in CSFs revealed that 68% of CSF samples obtained from patients with MS were positive (11 out of 16 samples) for chlamydia DNA. Thus, the protocol established here is sensitive enough to detect chlamydia DNA from CSFs and can be used by other laboratories for evaluation of the presence of chlamydiae in CSFs because the protocol is based on the use of a commercial kit.

Chlamydophila Infections↗

PubMed2001

Central volume expansion is pivotal for sustained decrease in heart rate during seated to supine posture change.

During prolonged, static carotid baroreceptor stimulation by neck suction (NS) in seated humans, heart rate (HR) decreases acutely and thereafter gradually increases. This increase has been explained by carotid baroreceptor adaptation and/or buffering by aortic reflexes. During a posture change from seated to supine (Sup) with similar carotid stimulation, however, the decrease in HR is sustained. To investigate whether this discrepancy is caused by changes in central blood volume, we compared (n = 10 subjects) the effects of 10 min of seated NS (adjusted to simulate carotid stimulation of a posture change), a posture change from seated to Sup, and the same posture change with left atrial (LA) diameter maintained unchanged by lower body negative pressure (Sup + LBNP). During Sup, the prompt decreases in HR and mean arterial pressure (MAP) were sustained. HR decreased similarly within 30 s of NS (65 +/- 2 to 59 +/- 2 beats/min) and Sup + LBNP (65 +/- 2 to 58 +/- 2 beats/min) and thereafter gradually increased to values of seated. MAP decreased similarly within 5 min during Sup + LBNP and NS (by 7 +/- 1 to 9 +/- 1 mmHg) and thereafter tended to increase toward values of seated subjects. Arterial pulse pressure was increased the most by Sup, less so by Sup + LBNP, and was unchanged by NS. LA diameter was only increased by Sup. In conclusion, static carotid baroreceptor stimulation per se causes the acute (<30 s) decrease in HR during a posture change from seated to Sup, whereas the central volume expansion (increased LA diameter and/or arterial pulse pressure) is pivotal to sustain this decrease. Thus the effects of central volume expansion override adaptation of the carotid baroreceptors and/or buffering of aortic reflexes.

Adaptation, Physiological↗

PubMed2001

Actinidic acid, a new triterpene phytoalexin from unripe kiwi fruit.

Seven phytoalexins (1-7), including a new compound, were isolated from the peel of unripe kiwi fruit (Actinidia deliciosa cv. Golden King) that had been wounded and inoculated with Colletotrichum musae. The new phytoalexin (1) was identified as 2alpha,3beta,23-trihydroxy-12,20(30)-ursadien-28-oic acid, and named actinidic acid. Phytoalexins 2-6 are known triterpenes but have not previously been described as phytoalexins. Phytoalexin 7 is the same triterpene as the phytoalexin of nectarine fruit.

Colletotrichum↗

PubMed2001

An adult case of congenital external carotid-jugular arteriovenous fistula with reversible circulatory insufficiency in the cerebellum and lower brain stem.

A 27-year-old man with congenital external carotid-jugular arteriovenous fistula presented with a diminished level of consciousness and an ataxic gait. Axial fluid-attenuated inversion-recovery (FLAIR) MR imaging revealed venous congestion, a dilated right jugular vein, and an area of high signal intensity in the brain stem and cerebellum. Angiography showed a dilated right external carotid artery and jugular vein and the presence of a fistula. After coil embolization of the fistula, axial MR FLAIR images showed only a few areas of high signal intensity in the brain stem and cerebellum. The causal factor was venous congestion in the inferior petrosal sinus and basilar plexus due to high blood pressure in the jugular vein. This case is presented for its unusual clinical and radiologic findings.

Adult↗

PubMed2000

Isolation and localization of type IIb Na/Pi cotransporter in the developing rat lung.

Differential display analysis of rat lung at different developmental stages identified a fragment, HG80, which appeared on embryonic day 16.5 and thereafter. A full-length cDNA derived from a cDNA library of newborn rat lung probed with HG80 was the rat counterpart of sodium-dependent phosphate transporter type IIb and was designated rNaPi IIb. In situ hybridization showed that rNaPi IIb was expressed in type II alveolar cells, suggesting a role in the synthesis of surfactant in the alveoli. The time-dependent changes in localization of this gene in the developing lung and its possible use as a type II pneumocyte marker are discussed.

Animals↗

PubMed2000

Triterpene phytoalexins from strawberry fruit.

Strawberry cv. Houkouwase is resistant to infection by Colletotrichum fragariae. The formation of antifungal compounds was observed in unripe fruit which had been wounded and inoculated with conidia of C. musae. Three antifungal compounds were isolated and identified as euscaphic acid, tormentic acid and myrianthic acid. Myrianthic acid inhibited the growth of C. musae at 3 microg, and euscaphic and tormentic acids showed inhibitory effects at 100 microg. A quantitative analysis of their contents showed that the triterpenes increased in wounded fruit, and in wounded and inoculated fruit, but not in non-treated fruit. These findings indicate that unripe fruit of Houkouwase produced the triterpenes as phytoalexins. The triterpene phytoalexins seem to be involved in the resistance of strawberry to the fungus.

Anti-Infective Agents↗

PubMed2000

Changes in the content and biosynthesis of phytoalexins in banana fruit.

Changes in the phytoalexin content in unripe fruit of banana, Musa acuminata, were analyzed after various treatments. The results show that level of hydroxyanigorufone started to increase 1-2 day after either wounding or inoculation with conidia of Colletotrichum musae. Inoculation followed by wounding induced the formation of many other phenylphenalenones. The accumulation of hydroxyanigorufone decreased, after its transient maximum, on ripening by exposure of the wounded fruit to ethylene. The level of production of hydroxyanigorufone in ripe fruit treated by wounding and/or by inoculation was much lower than that in unripe fruit. 2-Aminooxyacetic acid, an inhibitor of phenylalanine ammonia-lyase (PAL), inhibited the accumulation of hydroxyanigorufone in wounded fruit, and the PAL activity increased after wounding and ethylene treatment, respectively. Feeding experiments with [1-(13)C] and [2-(13)C]cinnamic acids, and [2-(13)C]malonate show that two molecules of cinnamic acid and one of malonate were incorporated into each molecule of hydroxyanigorufone. The phytoalexins isolated from fruit to which deuterated hydroxyanigorufone and irenolone had been administered revealed that 2-(4'-hydroxyphenyl)-1,8-naphthalic anhydride was biosynthesized from hydroxyanigorufone rather than from irenolone.

Chromatography, High Pressure Liquid↗

PubMed2000

Expression of the OGG1-type 1a (nuclear form) protein in cancerous and non-cancerous human cells.

The human OGG1 gene encodes 8-hydroxyguanine DNA glycosylase. By RT-PCR analysis, five novel type 1 transcripts, in addition to eight known types (OGG1-types 1a to 1c and 2a to 2e), were identified. Among them, only the type 1a isoform contains both a nuclear localization signal and the entire DNA binding motif, suggesting the involvement of type 1a in chromosomal DNA repair. By Western blot analysis using a monoclonal antibody prepared by immunizing the whole type 1a protein, a 39 kDa type 1a protein was detected in lung cancer cell lines and peripheral lymphocytes. The type 1a protein was expressed at a similar level, irrespective of its polymorphic types characterized by distinct repair activity. By an immunocytochemical study, the majority of type 1a protein was localized in the nucleus. These results indicate that OGG1-type 1a protein is involved in the repair of 8-hydroxyguanine in chromosomal double-stranded DNA and constitutively expressed in cancerous and non-cancerous human cells.

3T3 Cells↗

PubMed1999

Natural course of combined limb and palatal tremor caused by cerebellar-brain stem infarction.

After infarction of the left superior cerebellar peduncle and dentate nucleus, a patient developed tremor of the left upper limb beginning on the twelfth day followed by palatal tremor appearing 10 months after infarction. Surface electromyogram revealed a difference in the frequency of the tremor in the upper limb and soft palate. When the palatal tremor appeared, brain magnetic resonance T2-weighted images revealed high signal intensity of the contralateral, right inferior olivary nucleus. Subsequently, when the amplitude of palatal tremor became less severe, the high olivary signal intensity subsided whereas the hypertrophy of the nucleus remained. This patient provides useful information on the pathogenesis of skeletal and palatal tremor with brain stem or cerebellar lesions based on the differences in the onset and frequency of tremors and morphologic changes in the inferior olive.

Arm↗

PubMed1999

[A case of transverse myelitis caused by primary antiphospholipid antibody syndrome].

A 14-year-old man was admitted with sudden onset of paralysis in his lower extremities paralysis and of sensory loss below Th10 level. On admission, linear high intensity signals was seen in the spinal cord from Th 8 to Th 12 level on thoracic MRI T2 weighted image. Laboratory data on admission indicated existence of lupus anticoagrant in the patient's serum. Systemic lupus erythematodes was negative in his past history. The diagnosis of transverse myelitis caused by primary antiphospholipid syndrome was made accordingly. Plasmapheresis was performed to remove the lupus anticoagrant. After plasma pheresis coagulopathy was normalized with disappearance of the lupus anticoagrant. The lesion of the spinal cord is too extensive to be caused by single obstruction of any one blood vessel branch of the spinal cord. The transverse myelitis may be aggravated by the direct invasion of the lupus anticoagrant into nervous tissue from the vasculature whose blood brain barrier had been compromised by intravascular coagulation of this substance.

Adolescent↗

PubMed1998

Interaction of EphB2-tyrosine kinase receptor and its ligand conveys dorsalization signal in Xenopus laevis development.

The Eph class is the largest family of receptor tyrosine kinases and has been shown to play various roles in neural development including axon pathfinding and neural crest migration. EphB2 associates with transmembrane ligands Ephrin-B1 and -B2, which leads to tyrosine phosphorylation of both the ligands and receptor and is presumed to regulate cell-to-cell interactions by bidirectional signaling. We have investigated the biological effects of the EphB2-induced signal in the early stage of Xenopus laevis development. Xenopus EphB2 transcripts were detected maternally and were expressed at equal levels between the ventral and dorsal halves of the gastrulae, with expression increasing after the late gastrula stage. EphB2 mRNA expression in dorsal marginal zone explants from gastrulae increases during later development while that in ventral explants does not. We show here that microinjection of RNA encoding EphB2 into a ventral blastomere of embryos induced a partial secondary dorsal axis which consisted of neural tissues, notochord and somites. Analysis with molecular markers verified that the microinjected EphB2 dorsalized the mesoderm of ventral marginal zone explants. These dorsalizing effects of EphB2 in both the whole embryo and ventral explants were inhibited by the coinjection of RNA encoding the soluble form of Ephrin-B1. Furthermore, co-injection of EphB2 and Ephrin-B1 RNAs synergistically enhanced the dorsalization effect. These data show that the interaction between EphB2 and its ligands including Ephrin-B1 causes signaling events which lead to dorsal development, and strongly suggests the existence of proteins which mediate the dorsalization induced by EphB2 in early stage embryos of Xenopus laevis.

Amino Acid Sequence↗

PubMed1998

Vertical gaze palsy induced by midbrain lesions and its structural imaging.

We experienced four cases of vertical gaze palsy induced by midbrain lesions. Lesions commonly covered the rostral midbrain, including the rostral interstitial nucleus, dorsomedial to the red nucleus. Two of the four cases resulted from vascular insult, in which a single, unpaired perforator is supposed to innervate the rostral midbrain and medial thalamus bilaterally. One case showed vertical gaze palsy accompanied by bilateral ptosis. The findings agree with recent experimental evidence that a neural substrate in eyelid control lies in the supraoculomotor area immediately dorsal to the oculomotor nucleus. The remaining two cases, a brain hemorrhage and an inflammatory tumor, showed unilateral lesions of the rostral midbrain. In these cases, vertical gazes were not abolished, but were limited in an incomplete way. This may be explained by partial damages of the descending fibers, some of which decussate through the posterior commissure before it reaches the oculomotor nucleus. Thus, clinical signs and symptoms were clarified based on anatomical and physiological points of view.

Adult↗

PubMed1998

Study of the pharmacokinetics of cefpirome sulphate in the elderly.

OBJECTIVE: To determine the appropriate method of administration of the cephem antibiotic cefpirome sulphate in elderly patients. METHOD: We studied cefpirome's pharmacokinetics in patients with urinary tract infections. Patients received cefpirome sulphate 0.5 g by intravenous drip infusion over 30 mins. RESULTS: Patients with a creatinine clearance rate (Ccr) of 80 ml/min had an AUC of 96.7 microg.h/ml and a T1/2 of 2.36 h, whereas those with Ccr of 40-80 ml/min had an AUC of 172.0 microg.h/ml and a T1/2 of 3.45 h and those with Ccr of < 40 ml/min had an AUC of 152 microg.h/ ml and a T1/2 of 4.86 h. CONCLUSION: These results indicate that decreased kidney function can cause increases in the AUC and T1/2 of cefpirome. Thus in elderly patients and perhaps also in other patients with decreased kidney function, cefpirome should be administered at an initial dose of 0.5 g.

Aged↗

PubMed1998

Collagen and elastin synthesis by desmoid tumor in vitro.

In order to characterize human desmoid tumors in vitro, the production of collagen and elastin and the expression of collagen types alpha1(I), alpha1(III) and transforming growth factor (TGF)-beta1 mRNA were investigated in six desmoid tumors; five derived from familial adenomatous polyposis patients and one from a sporadic case. The proportion of collagen production to total protein production was determined by 3H-imino acid incorporation, an indicator of collagen synthesis, using high-performance liquid chromatography (HPLC). The proportion of collagen production to total protein production was much higher in all six desmoid tumors compared with human skin fibroblasts (HSF). Quantitatively, the rate of elastin synthesis in desmoid tumor cells monitored by valine-proline peptide was also significantly higher than in HSF. Pro-alpha1(I) collagen mRNA was highly expressed in both desmoid tumors and HSF at approximately the same level, whereas pro-alpha1(III) collagen mRNA was more abundant in some of the desmoid tumors than the normal skin fibroblastic cell lines. Tumor growth factor-beta1 mRNA, which is believed to stimulate collagen synthesis, was expressed in both desmoid tumors and HSF to the same extent. These results demonstrate the increased formation of collagen and elastin in desmoid tumors in vitro and suggest that the increased synthesis of elastin rather than of collagen and TGF-beta1 may be involved in increased fibrogenesis by desmoid tumors.

Adenomatous Polyposis Coli↗

PubMed1997

Origin of intraepithelial apoptotic cells in human colorectal adenomas.

The origin of intraepithelial apoptotic cells in human colorectal adenomas was examined using immunohistochemistry. Tissue sections of human colorectal adenomas obtained during surgery or endoscopy were stained by the streptavidinbiotin method using antibodies against carcinoembryonic antigen (CEA) and leukocyte common antigen (LCA). Approximately 15.7% of apoptotic bodies stained positive for CEA with immunoreactivity on the cytoplasm, whereas all cells stained negative for LCA. These findings suggest that intraepithelial apoptosis in human colorectal adenomas originates from adenoma cells rather than infiltrating lymphocytes as previously proposed, and that apoptotic cells maintained their cytoplasmic antigenicity in the early stages of apoptosis.

Adenoma↗

PubMed1997

[A patient with unilateral atrophy of trigeminal nerve-innervated muscle associated with contralateral glossopharyngeal and vagal neuropathy].

A 23-year-old woman was admitted to our hospital because of the left cheek swelling. On neurological examination, marked muscle atrophy of the right masseter muscle was recognized on chewing. The jaw was not deviated when she opened her mouth. Corneal reflex and the sensation on the face were intact. Curtain phenomenon was observed on the right side. The hypesthesia in the left palatal mucosa was observed. Routine laboratory data including cerebrospinal fluid analysis were normal. EMG from the right masseter muscle was not elicited, but normal in the left masseter muscle. The CT scan showed atrophy and low density areas in the right masseter, temporalis, lateral and medial pterygoid muscles, and hypertrophy in left masseter muscle. The MRI on T1 and T2 images confirmed the above muscle involvement. The etiology of trigeminal motor neuropathy, glossopharyngeal and vagal neuropathy were unknown. Masseter muscle hypertrophy was thought to be work hypertrophy compensated for the contralateral muscular atrophy.

Adult↗