Biomedical subjects

M Ikegami

Publications and source records attributed to M Ikegami.

At least 73 records · Page 4Linked to original sources

PubMed2000

Lung injury and surfactant metabolism after hyperventilation of premature lambs.

We asked whether lung injury and surfactant metabolism differed in preterm lambs after a 1-h period of hyperventilation to P(CO2) values of 25-30 mm Hg. The lambs then were surfactant treated and conventionally ventilated (CV) or high-frequency oscillatory ventilated (HFOV) for an additional 1 or 8 h. The results were compared with lambs that were not hyperventilated or surfactant treated but were ventilated with CV or HFOV. The 1-h hyperventilation resulted in increased alveolar protein, increased recovery of intravascular [131I]albumin in the lungs, and an increase in tumor necrosis factor-alpha mRNA. There were no differences between CV or HFOV in alveolar or total lung recoveries of saturated phosphatidylcholine (Sat PC), tracer doses of [14C]Sat PC and [125I]surfactant protein-B, or in percent Sat PC in large aggregate surfactant in surfactant-treated lambs. The lambs not hyperventilated or treated with surfactant had lower large aggregate pools and lower recoveries of [14C]Sat PC and [125I]surfactant protein-B in total lungs than for the surfactant-treated lungs, but there were no differences between the CV and HFOV groups. Hyperventilation followed by surfactant treatment resulted in a mild injury, but the subsequent use of CV or HFOV did not result in differences in surfactant metabolism.

Animals↗

PubMed2000

Antenatal glucocorticoids alter postnatal preterm lamb renal and cardiovascular responses to intravascular volume expansion.

We assessed renal and cardiovascular function in preterm newborn lambs after antenatal glucocorticoid exposure. Pregnant ewes were randomly assigned to receive betamethasone or saline via either direct fetal or maternal injection at 122 d gestation. Lambs were delivered 15 h later, and cardiovascular and renal function was assessed. Two hours after delivery, baseline urine flow, urinary sodium excretion, and urinary osmolar clearance were similar in all groups. Volume expansion (saline, 2.5% of body weight, for 10 min) increased values for urine flow (0.23 +/- 0.04 to 0.58 +/- 0.09 mL x min(-1) x kg(-1)), urinary sodium excretion (29.7 +/- 5.8 to 76.2 +/- 12.3 microEq x min(-1) x kg(-1)), and osmolar clearance (12.2 +/- 1.2 to 24.3 +/- 1.6 mL/100 mL GFR) in the fetal group. Increases in urine values were also observed in the maternal group, but control values did not change significantly. Mean arterial pressure was increased in both betamethasone-treated groups relative to controls. Short-term antenatal betamethasone exposure 1) augments preterm newborn kidney adaptive responses to acute volume expansion, and 2) increases postnatal blood pressure in preterm newborn lambs.

Aldosterone↗

PubMed2000

Prolonged survival in hereditary surfactant protein B (SP-B) deficiency associated with a novel splicing mutation.

Hereditary surfactant protein B (SP-B) deficiency has been lethal in the first year of life without lung transplantation. We tested the hypothesis that SP-B gene mutations may result in milder phenotypes by investigating the mechanisms for lung disease in two children with less severe symptoms than have been previously observed in SP-B deficiency. Immunostaining patterns for pulmonary surfactant proteins were consistent with SP-B deficiency in both children. DNA sequence analysis indicated that both children were homozygous for a mutation in exon 5 that created an alternative splice site. Reverse transcriptase PCR and sequence analysis confirmed use of this splice site, which resulted in a frameshift and a premature termination codon in exon 7. The predominant reverse transcriptase PCR product, however, lacked exon 7, which restored the reading frame but would not allow translation of the exons that encode mature SP-B. Western blot analysis detected reduced amounts of mature SP-B as well as an aberrant SP-B proprotein that corresponded to the size expected from translation of the abnormal transcript. We conclude that a novel splicing mutation was the cause of lung disease in these children and that hereditary SP-B deficiency can be the cause of lung disease in older children.

Female↗

PubMed2000

Antenatal endotoxin and glucocorticoid effects on lung morphometry in preterm lambs.

In utero inflammation may accelerate fetal lung maturation but may also play a role in the pathogenesis of chronic lung disease. We examined the impact of endotoxin, a potent proinflammatory stimulus, on structural and functional maturation of preterm sheep lungs. Date bred ewes received 20 mg Escherichia coli endotoxin or saline by ultrasound guided intra-amniotic injection at 119 d gestation. A comparison group of animals received 0.5 mg/kg betamethasone, a known maturational agent, at 118 d gestation. Lambs were delivered by cesarean section at 125 d (term = 150 d) and ventilated for 40 min. Lung function data are reported elsewhere. Total and differential white cell counts were performed on amniotic fluid and fetal lung fluid samples. Morphometric analyses were performed on inflation fixed right upper lobes. Total cell count increased slightly but not significantly in both amniotic fluid and fetal lung fluid. Both endotoxin and betamethasone had similar effects on alveolarization: average alveolar volume increased by approximately 20% and total alveolar number decreased by almost 30%. Both treatments led to thinning of alveolar walls, although this was statistically significant in the betamethasone-treated group only. Although antenatal endotoxin leads to striking improvements in postnatal lung function, this may be at the expense of normal alveolar development.

Amniotic Fluid↗

PubMed2000

Sodium ATPase and sodium/proton antiporter are not obligatory for sodium homeostasis of Enterococcus hirae at acid pH.

Enterococcus hirae grows in a broad pH range from 5 to 11. An E. hirae mutant 7683 lacking the activities of two sodium pumps, Na+-ATPase and Na+/H+ antiporter, does not grow in high Na+ medium at pH above 7.5. We found that 7683 grew normally in high Na+ medium at pH 5.5. Although an energy-dependent sodium extrusion at pH 5.5 was missing, the intracellular levels of Na+ and K+ were normal in this mutant. The Na+ influx rates of 7683 and two other strains at pH 5.5 were much slower than those at pH 7.5. These results suggest that Na+ elimination of this bacterium at acid pH is achieved by a decrease in Na+ entry and a normal K+ uptake.

Adenosine Triphosphatases↗

PubMed2000

[Clinical evaluation of low dose glucocorticoid therapy for hormone-refractory prostate cancer].

Fifteen cases with hormone-refractory metastatic carcinoma of the prostate were treated by the combination therapy of LH-RH analogue and low-dose glucocorticoid. Prior treatments of the patients were composed of maximum androgen blockade (MAB) therapy (14 cases) and bilateral orichiectomy (1 case). Nine of 15 cases underwent estramustine based treatment or anti-cancer chemotherapy as the second-line therapy. As a glucocorticoid (steroid) therapy, 1.5 or 2.0 mg of dexamethasone or 10 mg of predonisolone were given for a median period of nine months. Clinical responses were evaluated by the determination of serum PSA, EOD score and QOL scales. PSA responses were classified as CR, PR and PD according to the following categories; CR : PSA level decreased to less than 2 ng/ml, PR : PSA level decreased to less than half values of pretreatment level, PD: 20% or more increased to pretreatment level. PSA responses (CR + PR) were observed in eight of 15 patients for a median period of six months. Responses are seemed to be correlated with the Gleason scores. No apparent improvement on EOD scores by bone scintigraphy was seen, however, definite improvement of bone pain was identified in eight of 11 cases. The steroid therapy was considered as one of the useful treatment choice for patients with hormone-refractory prostate cancer.

Aged↗

PubMed2000

[Color Doppler ultrasonography in the diagnosis of the acute scrotum].

PURPOSE: To determine the value of color Doppler ultrasonography (CDUS) in the diagnosis of acute scrotum. MATERIALS AND METHODS: 10 patients referred to our hospital with acute scrotal pain were included in this study. All patients were evaluated with CDUS after the initial clinical examinations. Blood flow of the involved testis was compared semiquantitatively to that of the opposite testis. Patients with a diagnosis of testicular torsion by CDUS underwent surgical exploration. Patients with CDUS diagnosis of epididymitis were treated with intravenous antibiotics. RESULTS: Of the 10 patients evaluated, CDUS diagnosed 5 patients with testicular torsion and 5 patients with epididymitis. All cases of torsion were confirmed intraoperatively. 2 cases with no intratesticular blood flow on CDUS had necrotic testes and underwent orchiectomy with orchiopexy of the contralateral testes. A case with absent flow and 2 cases with decreased flow had bilateral orchiopexy. CDUS findings of normal or increased flow were present in all patients with epididymitis. No cases of testicular atrophy were encountered on long-term follow up in patients with epididymitis. CONCLUSION: CDUS is helpful in detecting the perfusion of the testis as well as in getting anatomical information. CDUS is a very useful device which causes a minimal burden to the patient with acute scrotum. In most cases it will rapidly provides us the correct information although it may not be regarded as the definitive adjunct.

Acute Disease↗

PubMed2000

[Giant bladder stone: a case report].

An 88-year-old woman was hospitalized with the chief complaints of lower abdominal pain, miction pain and pollakisuria. Radiographs showed a giant bladder stone shadow, 12.0 x 9.0 cm in size. Cystolithotomy was performed under the diagnosis of bladder stone. The extirpated stone weighed 510 g, and measured 10.0 x 7.5 x 6.0 cm in size. The stone had four compartments of stratified lamellae composed of calcium phosphate and magnesium ammonium phosphate. The postoperative course was uneventful and the bilateral hydronephrosis improved markedly on DIP.

Aged↗

PubMed1999

Enterococcus hirae vacuolar ATPase is expressed in response to pH as well as sodium.

The Enterococcus hirae ntp operon encodes both a vacuolar ATPase, which transports Na+ as well as Li+, and the KtrII K+ transporter. A plasmid, in which the chloramphenicol acetyltransferase gene (CAT) was placed downstream of the ntp promoter, was introduced into a mutant totally defective in Na+ extrusion. The CAT activity of this transformant was increased preferentially by addition of NaCl, but not by LiCl, in the media or by elevating the medium pH, correlating well with the increase in amounts of the ATPase subunits observed by Western blotting. The physiological significance of these responses of the ntp promoter is discussed.

Chloramphenicol O-Acetyltransferase↗

PubMed1999

Bis-N-nitroso-caged nitric oxides: photochemistry and biological performance test by rat aorta vasorelaxation.

Three new caged nitric oxides (NOs)-BNN3, BNN5Na, and BNN5M were tested for biological use. BNNs have a strong ultraviolet (UV) absorption band (lambda(max): 300 nm, epsilon: 13.5 mM(-1) cm (-1)) extended to 420 nm and produce NO upon irradiation with 300-360 nm light in quantum yields about 2. A photoexcited BNN molecule yields two NOs with time constants of less than 10 ns for phase 1 and less than 20 micros for phase 2 at 37 degrees C, suggesting usefulness of BNNs for measuring in vivo and in vitro fast NO reactions. Upon irradiating with UV light, caged nitric oxides-loaded rat aortic strips maintained in a state of active tonic contraction effectively relaxed ( < 3 microM BNN5M loading solution concentration). BNN3 is incorporated in the lipid membrane. BNN5Na, insoluble in organic solvents but water soluble, localizes in the water phase. BNN5M, is muscle-cell-permeable and hydrolysed to BNN5Na to remain in cytosol. BNNs were thermally stable and demonstrated no observable toxicity.

Animals↗

PubMed1999

Overexpression of rck/p54, a DEAD box protein, in human colorectal tumours.

The RCK gene is a target of the t(11;14)(q23;q32) chromosomal translocation observed in human B-cell lymphoma, and the overexpression of its protein (rck/p54) by the translocation was shown to cause malignant transformation. The rck/p54 protein belongs to the DEAD box protein/RNA helicase family, which has a variety of functions such as translation initiation, pre-mRNA splicing and ribosome assembly. The expression of rck p54 in colorectal adenocarcinoma cells was examined by immunohistochemistry and Western blot analysis. The rck/p54 protein was found to be overexpressed in tumour tissues resected from 13 (50%) out of 26 cases of colorectal adenocarcinomas and two out of two (100%) cases of colonic severe dysplastic adenomas. In view of activities of rck/p54 determined in other tissue types, we suggest that rck/p54 may contribute to the cell proliferation and carcinogenesis at the translational level in the development of colorectal tumours.

Adenocarcinoma↗

PubMed1999

Mucin histochemical analysis of minute gastric differentiated adenocarcinoma.

Fifty-six surgically resected intramucosal differentiated adenocarcinomas (DA) of the stomach with a maximum diameter of less than 5 mm were analyzed by mucin histochemistry. Gastric type phenotypic expression was observed in 41.1% of cases, intestinal type in 28.6% and gastric-intestinal type in 28.6% of all cancers. Gastric type phenotypic expression was the most frequent. As the tumor diameter increased, the incidence of DA with gastric phenotype tended to decrease. Intestinal metaplasia of the cancer's surrounding mucosa was absent or slight in DA with gastric phenotype, but moderate to severe in DA with gastric-intestinal phenotype and intestinal phenotype. Morphologically and mucin histochemically, intestinal metaplasia surrounding DA with gastric phenotype was immature and incomplete compared with DA with gastric-intestinal phenotype or intestinal phenotype. It is suggested that a large amount of DA with gastric phenotype is histogenetically derived from the gastric gland proper without intestinal metaplasia. However, as the tumor grows and intestinal metaplasia progresses, intestinal type phenotypic expression appears and then DA with gastric phenotype changes into DA with gastric-intestinal phenotype or intestinal phenotype.

Adenocarcinoma↗

PubMed1999

Renal responses to angiotensin II receptor blockade in ventilated preterm newborn lambs.

UNLABELLED: Renal and cardiovascular immaturity has been linked with poor outcomes in the premature human newborn. Despite extensive study in the fetus, the contribution of the renin-angiotensin system to renal and cardiovascular function in the premature newborn has not been well characterized. To evaluate the angiotensin II contribution to preterm newborn renal and cardiovascular functions, preterm (120-day) and near-term (136-day) lambs were Caesarean delivered and ventilated. One hour following delivery, animals were randomized to receive angiotensin II receptor-blockade (saralasin; 20 microg kg(-1) min(-1)) or saline (CON). Prior to blockade, mean +/- SEM values for urine flow (U(Flow)), urinary sodium excretion (U(NaV)), and fractional excretion of sodium (FENa) were similar in all groups. Angiotensin II receptor-blockade decreased U(Flow), U(NaV) and FENa in the 120-day group with no changes in the 136-day animals. No changes in mean arterial pressure, or plasma angiotensin II, aldosterone, and renin activity levels were noted at either gestational age. CONCLUSIONS: (1) angiotensin II contributes to the regulation of renal function in 120-day preterm lambs without changing blood pressure and (2) angiotensin II-mediated feedback inhibition of renin release is uncoupled in preterm newborns.

Aldosterone↗

PubMed1999

Complete nucleotide sequence and the genome organization of tobacco leaf curl geminivirus from Japan.

The genomic DNA of tobacco leaf curl geminivirus (TLCV) from tomato plants with leaf curl disease in Japan has been sequenced. The single circular DNA molecule comprises 2,761 nucleotides. TLCV DNA contains six open reading frames (ORFs) capable of encoding proteins with a molecular weight greater than 10 K. In total nucleotide sequence comparisons with other geminiviruses, TLCV was most closely related to tomato leaf curl virus from Taiwan (TwToLCV) (76% identity), tomato leaf curl virus from Bangalore (ToLCV-Ba) (74%) and agerantum yellow vein virus (AYVV) (74%), all possessing a monopartite genome. The significant but relatively low sequence similarity in the genomic DNA between TLCV and other geminiviruses suggests it is a distinct geminivirus in genus Begomovirus.

Base Sequence↗

PubMed1999

Aerosolized GM-CSF ameliorates pulmonary alveolar proteinosis in GM-CSF-deficient mice.

Surfactant proteins and phospholipids accumulate in the alveolar spaces and lung tissues of mice deficient in granulocyte-macrophage colony-stimulating factor (GM-CSF), with pathological findings resembling the histology seen in the human disease pulmonary alveolar proteinosis (PAP). Previous metabolic studies in GM-CSF-deficient [GM(-/-)] mice indicated that defects in surfactant clearance cause the surfactant accumulation in PAP. In the present study, GM(-/-) mice were treated daily or weekly with recombinant mouse GM-CSF by aerosol inhalation or intraperitoneal injection for 4-5 wk. Lung histology, alveolar macrophage differentiation, and surfactant protein B immunostaining returned toward normal levels in the GM-CSF aerosol-treated mice. Alveolar and lung tissue saturated phosphatidylcholine and surfactant protein B concentrations were significantly decreased after treatment with aerosolized GM-CSF. Cessation of aerosolized GM-CSF for 5 wk resulted in increased saturated phosphatidylcholine pool sizes that returned to pretreatment levels. In contrast, PAP did not improve in GM(-/-) mice treated daily for 5 wk with larger doses of systemic GM-CSF. Aerosolized GM-CSF improved PAP in the GM(-/-) mice, demonstrating that surfactant homeostasis can be influenced by local administration of GM-CSF to the respiratory tract.

Administration, Inhalation↗

PubMed1999

CCSP deficiency does not alter surfactant homeostasis during adenoviral infection.

Clara cell secretory protein (CCSP) deficiency in mice is associated with increased susceptibility to pulmonary inflammation after hyperoxia or viral infection. Because adenoviral exposure perturbs pulmonary surfactant homeostasis in vivo, we hypothesized that CCSP deficiency would influence surfactant metabolism after pulmonary infection. Alveolar and total lung saturated phosphatidylcholine pool sizes were similar in CCSP-deficient [CCSP(-/-)] and wild-type [CCSP(+/+)] mice before and 7 days after intratracheal administration of adenovirus. Radiolabeled choline and palmitate incorporation into saturated phosphatidylcholine was similar, and there was no alteration by previous infection 7 days before the incorporation measurements. Furthermore, CCSP deficiency did not influence clearance of [(14)C]dipalmitoylphosphatidylcholine and (125)I-labeled recombinant surfactant protein C. Increased persistence of alveolar capillary leak was observed in CCSP(-/-) mice after adenoviral infection. Surfactant lipid homeostasis was not influenced by CCSP before or after administration of adenovirus to the lung. Persistence of alveolar capillary leak in CCSP(-/-) mice after adenovirus provides further evidence for the role of CCSP in the regulation of pulmonary inflammation.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1999

Surfactant protein C in fetal and ventilated preterm rabbit lungs.

The developing lung contains surfactant protein (SP) C mRNA levels comparable to term values before mature type II cells and alveolar surfactant lipids are detectable. Estimates of the amount of mature SP-C in the alveolar lavages of preterm lungs are not available. We used an antibody to a recombinant human SP-C to measure the amount of SP-C in alveolar lavages of preterm fetal rabbits, ventilated preterm rabbits, and term rabbits. The amounts of SP-C were compared with the amounts of saturated phosphatidylcholine (Sat PC). Median Sat PC amounts increased about 680-fold, and median SP-C values increased by over 5,000-fold in alveolar washes from 27 days gestation to term. There was no increase in Sat PC or SP-C with ventilation at 27 and 28 days gestation, but ventilation increased both Sat PC and SP-C at 29 days gestation. The molar percent of SP-C relative to Sat PC also increased with gestational age and with ventilation at 29 days gestation. proSP-C was abundant in a membrane fraction from lung tissue at 27 and 28 days gestation when minimal mature SP-C was detected in alveolar washes. At 29 days and at term, proSP-C decreased in membrane fractions. The preterm lung that is surfactant lipid deficient is also severely deficient in mature SP-C.

Animals↗

PubMed1999

Developmental and glucocorticoid regulation of surfactant protein mRNAs in preterm lambs.

Glucocorticoid treatment increases content of surfactant protein (SP) A and SP-B in lung tissue and lavage fluid of preterm lambs. To investigate this process, we determined the ontogeny and glucocorticoid induction of SP mRNAs. In separate treatment protocols, each with its own controls, sheep were injected with betamethasone 15 h, 48 h, or weekly for 1-4 doses before preterm delivery. Using ovine SP cDNAs, we found an increase equal to or more than threefold in basal levels of all three SP mRNAs between 125 days and term. After betamethasone treatment, SP-B and SP-C mRNA levels increased by 15 h and all SP mRNAs were elevated after 24 h (>/=2-fold); mRNA levels in fetuses delivered 1-3 wk after betamethasone were not different from control. We conclude that in vivo betamethasone rapidly induces a coordinated increase in SP mRNAs, which is fully reversible within 7 days despite repetitive doses of betamethasone. Similar increases in mRNA and protein contents for SP-A and SP-B suggest that glucocorticoid regulation of these SPs in vivo is primarily pretranslational.

Animals↗