Biomedical subjects

N Suzuki

Publications and source records attributed to N Suzuki.

At least 379 records · Page 21Linked to original sources

PubMed1999

Proliferation of parathyroid cells negatively correlates with expression of parathyroid hormone-related protein in secondary parathyroid hyperplasia.

BACKGROUND: Parathyroid hormone-related protein (PTHrP) is now suspected to act as an autocrine or paracrine regulator of cell growth or differentiation, although it was originally reported as a hypercalcemic substance in malignancies. This study was performed to assess the relationship between PTHrP expression and cell proliferation in human parathyroid glands. METHODS: The localization of PTH and PTHrP was studied in 42 samples of hyperplastic parathyroid from 14 long-term hemodialysis cases with immunohistochemistry and in situ hybridization. Results were compared with proliferative activity (proliferating cell nuclear antigen index: counts of proliferating cell nuclear antigen-positive cells/100 cells). The localization of the PTH/PTHrP receptor was also examined. Ten normal glands were studied as controls. RESULTS: In hyperplasia, cells positive for PTH, PTHrP, or both were observed immunohistochemically. The areas expressing PTHrP mRNA completely coincided with those positive for PTHrP immunohistochemically. Oxyphilic or transitional oxyphilic cells were consistently positive for PTHrP. PTH/PTHrP receptors were located in the cytoplasmic membrane in most parathyroid cells. Proliferating cell nuclear antigen-positive cells were rare in normal glands with an index of 0. 22 +/- 0.09 (mean +/- sem). They were significantly increased in hyperplastic cases but less for PTHrP-positive than for -negative cells (1.25 +/- 0.16 as compared with 7.80 +/- 0.52; P < 0.0001). CONCLUSION: The observed low level of proliferation of PTHrP-positive cells suggests a functional role for PTHrP as a possible growth suppressor in the human parathyroid.

Adult↗

PubMed1999

Role of Ca(2+)-ATPase in spontaneous oscillations of cytosolic free Ca2+ in GH3 rat pituitary cells.

The relative contribution of voltage-sensitive Ca2+ channels, Ca(2+)-ATPases, and Ca2+ release from intracellular stores to spontaneous oscillations in cytosolic free Ca2+ concentration ([Ca2+]i) observed in secretory cells is not well characterized owing to a lack of specific inhibitors for a novel thapsigargin (Tg)-insensitive Ca(2+)-ATPase expressed in these cells. We show that spontaneous [Ca2+]i oscillations in GH3 cells were unaffected by Ca2+ depletion in inositol-1,4,5-trisphosphate (IP3)-sensitive Ca2+ stores by the treatment of Tg, but could be initiated by application of caffeine. Moreover, we demonstrate for the first time that these spontaneous [Ca2+]i oscillations were highly temperature dependent. Decreasing the temperature from 22 to 17 degrees C resulted in an increase in the frequency, a reduction in the amplitude, and large inhibition of [Ca2+]i oscillations. Furthermore, the rate of ATP-dependent 45Ca2+ uptake into GH3-derived microsomes was greatly reduced at 17 degrees C. The effect of decreased temperatures on extracellular Ca2+ influx was minor because the frequency and amplitude of spontaneous action potentials, which activate L-type Ca2+ channels, was relatively unchanged at 17 degrees C. These results suggest that in GH3 secretory cells, Ca2+ influx via L-type Ca2+ channels initiates spontaneous [Ca2+]i oscillations, which are then maintained by the combined activity of Ca(2+)-ATPase and Ca(2+)-induced Ca2+ release from Tg/IP3-insensitive intracellular stores.

Animals↗

PubMed1999

Selective accumulation of CCR5+ T lymphocytes into inflamed joints of rheumatoid arthritis.

Chemokines and their receptors play critical roles in the selective recruitment of various subsets of leukocytes. Recent studies have indicated that some chemokine receptors are differentially expressed on Th1 and Th2 cells. However, available data concerning the presence of T cells with a Th1 or a Th2 character and the expression of chemokine receptors on infiltrating T cells in the rheumatic joint are still limited. In this study, we investigated the expression of CC chemokine receptor 4 (CCR4) and CCR5, which have been shown to be preferentially expressed on Th2 and Th1 respectively on T cells from rheumatoid arthritis (RA) patients. Although both CCR5+ and CCR4+ CD4+ T cell populations were observed in peripheral blood mononuclear cells from healthy controls and osteoarthritis patients, these cell populations were decreased in patients with active RA. In contrast, the vast majority of synovial fluid (SF) T cells from active RA patients expressed CCR5 but not CCR4. CCR5 ligands, MIP-1alpha and RANTES, were found in RA SF at high levels. CCR5+ CD4+ T cells from SF mononuclear cells of RA patients produced IFN-gamma but not IL-4 in response to anti-CD3 stimulation in vitro. These results indicated that differential expression of chemokine receptors plays a critical role for selective recruitment of pro-inflammatory T cells into the joints of RA.

Adult↗

PubMed1999

Pain-relieving posterior rod fixation with segmental sublaminar wiring for Pancoast tumor invading the vertebrae.

We describe the case of a 44-year-old male patient with Pancoast lung cancer invading the vertebrae. Because irradiation did not relieve his symptoms, we conducted tumor resection with posterior rod fixation with segmental sublaminar wiring of the vertebrae. This enabled the patient to walk and to discontinue morphine immediately after surgery. Although the tumor recurred within the region of the fixation 4 months after surgery, the patient complained of no pain until his death. Although Pancoast lung cancer with extensive vertebral invasion cannot be cured surgically, posterior rod fixation with segmental sublaminar wiring with tumor resection can improve a patient's quality of life by providing immediate, long-term pain relief.

Adult↗

PubMed1999

Sequence analysis of cDNA and genomic DNA, and mRNA expression of the medaka fish homolog of mammalian guanylyl cyclase C.

We isolated the cDNA and genomic DNA encoding a membrane guanylyl cyclase of medaka fish (designated as OlGC6), and determined their complete nucleotide sequences. The open reading frame for OlGC6 cDNA predicted a protein of 1,075 amino acids. Phylogenetic analysis indicated that OlGC6 is a member of the enterotoxin/guanylin receptor family. We also determined the partial genomic structure of the gene of another membrane guanylyl cyclase of medaka fish, OlGC2, which is a member of the natriuretic peptide receptor family. The intron positions relative to the protein-coding sequence are highly conserved in the intracellular domains of OlGC6, OlGC2, mammalian GC-A, and GC-E. Despite their divergent primary structures, some intron positions also seem to be conserved in the extracellular domains of different membrane guanylyl cyclase genes. Northern blot analysis demonstrated that an OlGC6 transcript of 3.9 kb is only present in the intestine, while reverse transcription (RT)-PCR analysis demonstrated that the OlGC6 transcript is present in the kidney, spleen, liver, pancreas, gallbladder, ovary, testis, brain, and eye. RT-PCR also demonstrated that OlGC6 is only expressed zygotically and that transcripts are present from 1 day after fertilization, i.e. long before the intestinal tissues begin to develop.

Amino Acid Sequence↗

PubMed1999

Genomic structure and expression of the medaka fish homolog of the mammalian guanylyl cyclase B.

We have isolated a 3.9-kbp-long cDNA and approximately 93 kbp long genomic DNA encoding a membrane guanylyl cyclase (designated OlGC1) from the medaka fish Oryzias latipes, and determined their nucleotide sequences. The open reading frame for the OlGC1 cDNA predicts a protein of 1,055 amino acids. Phylogenetic analysis indicates OlGC1 to be a medaka fish homolog of mammalian guanylyl cyclase B (GC-B), a member of the natriuretic peptide receptor family. Northern blot analysis demonstrated 3.9 kb OlGC1 transcripts in the eye and brain, while reverse transcription-polymerase chain reaction (RT-PCR) analysis showed OlGC1 transcripts in a number of adult peripheral organs as well as embryos during early stages of development. The OlGC1 gene consists of 22 exons with an exon/intron organization similar to that of the human and rat GC-A genes, except that OlGC1 has several very large introns. The OlGC1 gene has no apparent TATA box or CAAT box in the region 1.2 kbp upstream of the putative transcription initiation point, but several consensus sequences for cis-regulatory elements, including an NF-IL6-binding element, a shear stress responsive element, and multiple GM-CSF-binding elements, are present in that region.

Amino Acid Sequence↗

PubMed1999

Expression of trophinin, tastin, and bystin by trophoblast and endometrial cells in human placenta.

Trophinin, tastin, and bystin comprise a complex mediating a unique homophilic cell adhesion between trophoblast and endometrial epithelial cells at their respective apical cell surfaces. In this study, we prepared mouse monoclonal antibodies specific to each of these molecules. The expression of these molecules in the human placenta was examined immunohistochemically using the antibodies. In placenta from the 6th week of pregnancy, trophinin and bystin were found in the cytoplasm of the syncytiotrophoblast in the chorionic villi, and in endometrial decidual cells at the utero placental interface. Tastin was exclusively present on the apical side of the syncytiotrophoblast. Tissue sections were also examined by in situ hybridization using RNA probes specific to each of these molecules. This analysis showed that trophoblast and endometrial epithelial cells at the utero placental interface express trophinin, tastin, and bystin. In wk 10 placenta, trophinin and bystin were found in the intravillous cytotrophoblast, while tastin was not found in the villi. After wk 10, levels of all three proteins decreased and then disappeared from placental villi.

Antibodies, Monoclonal↗

PubMed1999

Low-dose GnRH agonist therapy for the management of endometriosis.

OBJECTIVE: In order to examine whether treatment with a GnRH agonist alone can maintain estrogen levels within the "estrogen window" that inhibits endometriosis without influencing bone-mineral density, we studied the effects of GnRH agonist therapy and changes in bone-mineral density. METHODS: Buserelin acetate nasal spray was administered 3 times a day for 8 weeks (daily dose, 900 micrograms) to 21 women with endometriosis. The drug was then given twice a day for 16 weeks (daily dose, 600 micrograms). The total duration of treatment was 24 weeks. The bone-mineral density of the lumbar vertebrae was measured by dual-energy X-ray absorptiometry before treatment (baseline), at the end of treatment, and 24 weeks after the end of treatment. RESULTS: The bone-mineral density of the lumbar vertebrae at the end of treatment was 2.44% +/- 0.46% (mean +/- standard error) lower than the baseline value. The value at 24 weeks after the end of treatment was 1.10% +/- 0.64% lower than the baseline value. More than 80% of the patients had serum-estradiol levels of 45 pg/ml or less. During treatment, more than 90% of the patients had serum-estradiol levels of 60 pg/ml or less. Genital bleeding was inhibited in 90% of the patients. After 8 weeks of treatment, the clinical symptoms improved in 75% of the patients; such improvement persisted for the duration of the treatment. CONCLUSION: Decreasing the dose of GnRH agonist during treatment can minimize the loss of bone-mineral density without lessening the beneficial effects on endometriosis. This technique might be useful in the management of endometriosis.

Abdominal Pain↗

PubMed1999

[Bacteriological studies of traveller's diarrhoea (6). Analysis of enteropathogenic bacteria at Kansai Airport Quarantine Station from September 4th, 1994 through December 1996].

During the period of investigation from Sept. 4, 1994 to Dec, 1996, a total of 11,446,534 overseas travellers were quarantined at Kansai Airport Quarantine Station, and 22,187 voluntarily reported of episodes suffering from diarrhoea. Bacteriological examination of the stools a total of 9,299 individuals' was performed, and the following results were obtained. 1) Various enteropathogenic bacteria were isolated from 33.3% of the stools examined. Bacterial species isolated were as follows: Plesiomonas shigelloides, 2,066 cases (66.7%); Vibrio parahaemolyticus, 358 cases (11.6%); Aeromonas sobria, 360 cases (11.6%); Shigella spp., 291 cases (9.4%); Salmonella spp., 183 cases (5.9%); A. hydrophila, 126 cases (4.1%); and V. cholerae non-O1, 121 cases (3.9%). However, ETEC was not done with an object of test. 2) In 502 cases (16.2%), plural enteropathogenic bacteria were isolated from single patient, suggesting high frequency of a mixed infections. 3) From Feb. to Mar. 1995, thirteen cases cholera were found from patients who had travelled to Bali, Indonesia. Cases with enteropathogenic bacteria other than V. cholerae O1 were found without any seasonal variation. 4) The major regions where the travellers were infected with the pathogens are as follows: Vibrio spp., were from only Asia; Shigella, widely distributed but especially in India and Indonesia; P. shigelloides and Salmonella, widely distributed. 5) Among the Shigella strains, S. sonnei were isolated the most, followed by S. flexneri, S. boydii and S. dysenteriae. A strain of S. boydii provisional serovar E 16553 was isolated from a patient infected in India. 6) Among the Salmonella serovars, Salmonella Enteritidis was isolated the most frequently (49 cases, 25.7%). 7) 265 (89.2%) of 297 Shigella strains, 52 (27.2%) of 19] Salmonella strains, and 19 (95.0%) of 20 V. cholerae O1 were resistant to one or more drugs tested (SM. CP. TC. KM. ABPC. NA. OFLX). 8) All of the 20 V. cholerae O1 strains were Ogawa, E1 Tor. All of them were toxigenic strains. 9) The most frequently isolated serovar of V. parahaemolyticus was O3: K6. 89.8% of all V. parahaemolyticus strains were positive for thermostable direct hemolysin (TDH) gene, and 14.6% of them were positive for TDH-related hemolysin (TRH) gene by DNA-probe or PCR method.

Asia, Southeastern↗

PubMed1999

[An analysis of fever of unknown origin defined by newly proposed practical criteria. A prospective study of 56 cases].

The criteria proposed by Petersdorf has been in use internationally to define the fever of unknown origin (FUO) since 1961 and the research of FUO has progressed with this criteria. Mean-while, new diagnostic methods have been developed and illness behavior of febrile patients has changed considerablly. Accordingly, the definition by Petersdorf is becoming less matched to current clinical situation. Therefore, we have developed a new practical criteria of FUO; i.e., out-patients who are febrile more than 2 weeks, documented temperature higher than 37.5 degrees C at least on one occasion and undetermined diagnosis and in-patients who are febrile more than 1 week with documented temperature higher than 37.5 degrees C, and undetermined diagnosis. Between October 1, 1993, and October 31, 1996, we prospectively collected a series of febrile patients who fulfilled our new criteria. We identified 56 patients by our criteria (23 male and 33 female, age: 49.7 +/- 20.6. range 15 to 88). Of this 56 patients, 19 (32%) were found to have infections, 18 (31%) had collagen disorders, 5 (9%) had malignancy and 6 (10%) had died. Of 56 patients, 38 (68%) were in the newly added group. Of these 38 patients, 4 patients had subacute necrotizing lymphoadenitis, 4 cytomegalovirus infection, 3 polymyalgia rheumatica, 3 tuberculosis. Four patients (10%) died. With our criteria, febrile patients who previously had not been included were found to have as poor a prognosis as with the Petersdorf group.

Adolescent↗

PubMed1999

Roles of CD4(+) T cells and gamma interferon in protective immunity against Babesia microti infection in mice.

Babesia microti produces a self-limiting infection in mice, and recovered mice are resistant to reinfection. In the present study, the role of T cells in protective immunity against challenge infection was examined. BALB/c mice which recovered from primary infection showed strong protective immunity against challenge infection. In contrast, nude mice which failed to control the primary infection and were cured with an antibabesial drug did not show protection against challenge infection. Treatment of immune mice with anti-CD4 monoclonal antibody (MAb) diminished the protective immunity against challenge infection, but treatment with anti-CD8 MAb had no effect on the protection. Transfer of CD4(+) T-cell-depleted spleen cells resulted in higher parasitemia than transfer of CD8(+) T-cell-depleted spleen cells. A high level of gamma interferon (IFN-gamma), which was produced by CD4(+) T cells, was observed for the culture supernatant of spleen cells from immune mice, and treatment of immune mice with anti-IFN-gamma MAb partially reduced the protection. Moreover, no protection against challenge infection was found in IFN-gamma-deficient mice. On the other hand, treatment of immune mice with MAbs against interleukin-2 (IL-2), IL-4, or tumor necrosis factor alpha did not affect protective immunity. These results suggest essential requirements for CD4(+) T cells and IFN-gamma in protective immunity against challenge infection with B. microti.

Adoptive Transfer↗

PubMed1999

Cloning and expression of a 48-kilodalton Babesia caballi merozoite rhoptry protein and potential use of the recombinant antigen in an enzyme-linked immunosorbent assay.

A cDNA expression library prepared from Babesia caballi merozoite mRNA was screened with a monoclonal antibody BC11D against the rhoptry protein of B. caballi merozoite. A cDNA encoding a 48-kDa protein of B. caballi was cloned and designated BC48. The complete nucleotide sequence of the BC48 gene had 1,828 bp and was shown to contain no intron. Southern blotting analysis indicated that the BC48 gene contained more than two copies in the B. caballi genome. Computer analysis suggested that this sequence contained an open reading frame of 1,374 bp with a coding capacity of approximately 52 kDa. The recombinant protein expressed by the vaccinia virus vector in horse cells had an apparent molecular mass of 48 kDa, which was the same as that of the native B. caballi 48-kDa protein. Moreover, recombinant proteins expressed by the pGEX4T expression vector in Escherichia coli as glutathione S-transferase fusion proteins were used for antigen in an enzyme-linked immunosorbent assay (ELISA). The ELISA was able to differentiate very clearly between B. caballi-infected horse sera and B. equi-infected horse sera or noninfected normal horse sera. These results suggest that this simple and highly sensitive test might be applicable to the detection of B. caballi-infected horses in the field.

Amino Acid Sequence↗

PubMed1999

Mapping of a hypovirus p29 protease symptom determinant domain with sequence similarity to potyvirus HC-Pro protease.

Hypovirus infection of the chestnut blight fungus Cryphonectria parasitica results in a spectrum of phenotypic changes that can include alterations in colony morphology and significant reductions in pigmentation, asexual sporulation, and virulence (hypovirulence). Deletion of 88% [Phe(25) to Pro(243)] of the virus-encoded papain-like protease, p29, in the context of an infectious cDNA clone of the prototypic hypovirus CHV1-EP713 (recombinant virus Deltap29) partially relieved virus-mediated suppression of pigmentation and sporulation without altering the level of hypovirulence. We now report mapping of the p29 symptom determinant domain to a region extending from Phe(25) through Gln(73) by a gain-of-function analysis following progressive repair of the Deltap29 deletion mutant. This domain was previously shown to share sequence similarity [including conserved cysteine residues Cys(38), Cys(48), Cys(70), and Cys(72)] with the N-terminal portion of the potyvirus-encoded helper component-proteinase (HC-Pro), a multifunctional protein implicated in aphid-mediated transmission, genome amplification, polyprotein processing, long-distance movement, and suppression of posttranscriptional silencing. Substitution of a glycine residue for either Cys(38) or Cys(48) resulted in no qualitative or quantitative changes in virus-mediated symptoms. Unexpectedly, mutation of Cys(70) resulted in a very severe phenotype that included significantly reduced mycelial growth and profoundly altered colony morphology. In contrast, substitution for Cys(72) resulted in a less severe symptom phenotype approaching that observed for Deltap29. The finding that p29-mediated symptom expression is influenced by two cysteine residues that are conserved in the potyvirus-encoded HC-Pro raises the possibility that these related viral-papain-like proteases function in their respective fungal and plant hosts by impacting ancestrally related regulatory pathways.

Ascomycota↗

PubMed1999

Central motor reorganization in cerebral palsy patients with bilateral cerebral lesions.

Transcranial magnetic stimulation (TMS) has been used to describe cortical plasticity after unilateral cerebral lesions. The objective of this study was to find out whether cortical plasticity occurs after bilateral cerebral lesions. We investigated central motor reorganization for the arm and leg muscles in cerebral palsy (CP) patients with bilateral cerebral lesions using TMS. Seventeen patients (12 with spastic diplegia, 1 with spastic hemiplegia, and 4 with athetoid CP) and 10 normal subjects, were studied. On CT/MRI, bilateral periventricular leukomalacia was observed in all spastic patients with preterm birth. In two normal subjects, motor responses were induced in the ipsilateral tibialis anterior, but no responses were induced in any normal subject in the ipsilateral abductor pollicis brevis (APB) or biceps brachii (BB). Ipsilateral responses were more common among CP patients, especially in TMS of the less damaged hemisphere in patients with marked asymmetries in brain damage: in 3 abductor pollicis brevis, in 6 BBs, and in 15 tibialis anteriors. The cortical mapping of the sites of highest excitability demonstrated that the abductor pollicis brevis and BB sites in CP patients were nearly identical to those of the normal subjects. In patients with spastic CP born prematurely, a significant lateral shift was found for the excitability sites for the tibialis anterior. No similar lateral shift was observed in the other CP patients. These findings suggest that ipsilateral motor pathways are reinforced in both spastic and athetoid CP patients, and that a lateral shift of the motor cortical area for the leg muscle may occur in spastic CP patients with preterm birth.

Adolescent↗

PubMed1999

Diurnal rhythms of luteinizing hormone, follicle-stimulating hormone, and testosterone secretion before the onset of male puberty.

To investigate hormonal change before the onset of male puberty, we measured LH and FSH in serum samples drawn every 20 min for 24 h and measured testosterone hourly for 24 h. Forty-six boys (32 prepubertal and 14 pubertal) of short stature, between 4.4-19.3 yr of age, participated in this study. LH and FSH were measured using a time-resolved immunofluorometric assay, and testosterone was measured using high sensitivity RIA capable of detecting a testosterone concentration of 0.01 ng/mL. Diurnal rhythms of LH, FSH, and testosterone were apparent in all subjects, including those aged 4-5 yr. Serum LH and FSH concentrations showed night-day variation in a pulsatile fashion. The serum testosterone concentration was elevated at early morning in all subjects. Mean 24-h LH, FSH, and testosterone concentrations of prepubertal subjects who did not attain puberty for at least 3 yr were 0.10 U/L, 0.63 U/L, and 0.06 ng/mL, respectively, whereas those of prepubertal subjects who attained puberty within 1 yr (0.54 U/L, 1.68 U/L, and 0.10 ng/mL, respectively) were significantly higher. Furthermore, mean 24-h LH, FSH, and testosterone concentrations increased with developing puberty. All of the 46 subjects showed positive cross-correlation between the LH and testosterone time series. The mean lag time from the LH to the testosterone time series in the prepubertal subjects who attained puberty within 1 yr (4.7 +/- 2.4 h, mean +/- SD) was shorter than that in the prepubertal subjects who attained puberty after at least 3 yr (7.3 +/- 2.2 h). This lag time decreased with developing puberty, plateauing at 1.4 +/- 0.9 h at midpuberty. Thus, the diurnal rhythms of LH, FSH, and testosterone already exist at 4-5 yr of age; serum LH, FSH, and testosterone levels increase before the onset of puberty; and a time delay is observed between the LH and testosterone time series that decreases before the onset of puberty.

Adolescent↗

PubMed1999

Effects of thyroid hormones on apoptotic cell death of human lymphocytes.

Apoptosis plays a critical role in the development and homeostasis of tissues, especially those with high cell turnover such as the lymphoid system. We have examined the effects of thyroid hormones, TSH and TRH, on apoptosis of human T lymphocytes. We found that T lymphocytes cultured with T3 and T4, but not TSH nor TRH, in vitro showed enhanced apoptosis, evidenced by DNA ladder formation and characteristic morphological changes. In addition, prolonged cultivation with thyroid hormones of the lymphocytes further enhanced the extent of apoptosis. We also found that treatment with thyroid hormones of T lymphocytes induced reduction of mitochondrial transmembrane potential (delta psi) and production of reactive oxygen species, both of which are intimately associated with apoptotic cell death. In addition, cellular expression of antiapoptotic Bcl-2 protein was clearly reduced by the treatment of lymphocytes with thyroid hormones in vitro. Thus, T lymphocytes treated with thyroid hormones accompany reduction of Bcl-2 protein expression, production of reactive oxygen species, and reduction of mitochondrial delta psi, resulting in apoptotic lymphocyte death. Moreover, we found that lymphocytes in patients with Graves' disease showed enhanced apoptosis compared with those in normal individuals. These results suggest that thyroid hormones have the potential to induce apoptotic cell death of human lymphocytes in vivo and in vitro.

Adult↗

PubMed1999

Magnesium dynamics and sympathetic nervous system activity in patients with chronic heart failure.

This study was undertaken in patients with heart failure to investigate the relation between plasma norepinephrine (NE) concentration and Mg dynamics. The study subjects comprised 16 patients with chronic heart failure (mean age 64.9+/-10.0 years). Cardiopulmonary exercise testing was performed on all patients, and anaerobic threshold (AT), peak oxygen uptake (peak VO2) and peak exercise time were measured. Resting and peak values of plasma NE concentration and serum and erythrocyte magnesium concentration were also measured. The results were as follows: the serum Mg concentration was increased significantly immediately after exercise (p<0.01), and the erythrocyte Mg concentration showed a tendency to decrease (p<0.1). The resting plasma NE level was inversely correlated with AT (p<0.05, r=-0.57), peak VO2 (p<0.05, r=-0.55) and peak exercise time (p<0.01, r=-0.62). When the plasma NE concentration at rest was analyzed in 2 groups of patients, ie, those with higher than average and those with lower than average concentrations, the resting erythrocyte Mg concentration was significantly lower in the high-NE group (2.2+/-0.3 mg/dl) than in the low-NE group (2.7+/-0.5 mg/dl) (p<0.05). The data indicate that patients with chronic heart failure associated with high NE levels at rest who showed low exercise tolerance have intracellular hypomagnesemia, which may be caused by Mg migration from intracellular to extracellular spaces.

Adult↗

PubMed1999

Exercise-induced changes in plasma atrial natriuretic peptide and brain natriuretic peptide concentrations in healthy subjects with chronic sleep deprivation.

Recent observations have shown that plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) correlate with cardiac function or prognosis in heart failure patients. However, relatively little is known about changes in their plasma concentration during commonly occurring physiological states such as fatigue. Therefore, this study was designed to examine the physiological changes of plasma ANP and BNP concentrations using a chronic sleep-deprivation model. Bicycle ergometer cardiopulmonary exercise tests were performed in 10 healthy volunteers (mean age: 22.7 years). Blood samples for measuring ANP and BNP were drawn during the resting state and immediately after each exercise test. Cardiac output (CO) was measured during the exercise test by the impedance method. The study conditions were designed as follows: (A) a day following a period of normal sleep (control state) and (B) a day preceded by 1 month during which sleep lasted <60% of normal (chronic sleep-deprived state). Results were as follows. (1) Peak oxygen uptake and peak CO decreased during the sleep-deprived state compared with the control state. (2) There was no difference between peak heart rates measured during exercise under the 2 conditions. (3) Plasma ANP concentration during exercise increased significantly during the control state, whereas only a tendency toward increase was observed during the sleep-deprived state. (4) Plasma BNP concentration during exercise tended to increase in the control state compared with the resting state, whereas there was no difference in plasma BNP between after exercise and resting state in the sleep-deprived state. These results indicate that changes of ANP or BNP induced by exercise tended to be decreased by chronic sleep deprivation.

Adult↗