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T Ikeda

Publications and source records attributed to T Ikeda.

At least 271 records · Page 15Linked to original sources
PubMed2000

Dramatic synergism between excess soybean intake and iodine deficiency on the development of rat thyroid hyperplasia.

The effects of defatted soybean and/or iodine-deficient diet feeding were investigated in female F344 rats. Rats were divided into four groups, each consisting of 10 animals, and fed basal AIN-93G diet in which the protein was exchanged for 20% gluten (Group 1), iodine-deficient gluten (Group 2), 20% defatted soybean (Group 3) and iodine-deficient defatted soybean (Group 4). At week 10, relative thyroid gland weights (mg/100 g body wt) were significantly (P < 0.01) higher in Groups 2 (15.5 +/- 1.3) and 4 (81.7 +/- 8.6) than in Group 1 (8.4 +/- 2.0) and pituitary gland weights (mg/100 g body wt) were significantly (P < 0.01) higher in Groups 3 (9.1 +/- 0. 6) and 4 (9.7 +/- 1.5) than in Group 1 (6.5 +/- 1.5). Serum biochemical assays revealed thyroxine to be significantly (P < 0.05) lower in Groups 2 and 4 than in Group 1. On the other hand, serum thyroid-stimulating hormone (TSH) was significantly (P < 0.01) higher in Groups 3 and 4 than in Group 1. This was particularly striking for TSH (ng/ml) at week 10 in Group 4 (126 +/- 11) as compared with Groups 1 (4.36 +/- 0.30), 2 (4.84 +/- 0.80) and 3 (5. 78 +/- 0.80). Histologically, marked diffuse follicular hyperplasia of the thyroid was evident in Group 4 rats. Proliferating cell nuclear antigen labeling indices (%) were significantly higher (P < 0.05) in Groups 2 (4.8 +/- 2.5) and 4 (13.2 +/- 1.1) than in Group 1 (0.4 +/- 0.5). Ultrastructurally, severe disorganization and disarrangement of mitochondria were apparent in thyroid follicular cells of Group 4. In the anterior pituitary, dilated rough surfaced endoplasmic reticulum and increased secretory granules were remarkable in this group. Our results thus strongly suggest that dietary defatted soybean synergistically stimulates the growth of rat thyroid with iodine deficiency, partly through a pituitary-dependent pathway.

Animals↗
PubMed2000

Effects of aging and dietary restriction on mRNA levels of receptors for growth hormone-releasing hormone and somatostatin in the rat pituitary.

Aging impairs and dietary restriction may modulate pituitary response to growth hormone (GH)-releasing hormone (GHRH) and somatostatin (SRIH) for GH secretion. Using the semiquantitative reverse-transcription polymerase chain reaction method, we analyzed the mRNA levels of the GHRH receptor (grfr) and SRIH receptor subtype 2 (sstr2) and subtype 5 (sstr5) in anterior pituitaries of male rats fed ad libitum or 30% dietary restricted. Aging reduced the mRNA levels of these receptors in a slightly different manner. The levels of grfr progressively decreased between 6 and 24 months, whereas those of sstr2 and sstr5 declined after 16 months. Dietary restriction did not diminish the aging-dependent changes, although it slightly augmented the levels of grfr, but not sstr2 and sstr5. The present results suggest that the aging-dependent impairment in pituitary response for GH secretion could result mostly from a decline in grfr rather than relative increase of sstrs. Although DR could slightly enhance the pituitary sensitivity to GHRH, the antiaging action may be minor at the level of gene expression.

Aging↗
PubMed2000

Impact of dialysis therapy on insulin resistance in end-stage renal disease: comparison of haemodialysis and continuous ambulatory peritoneal dialysis.

BACKGROUND: Insulin resistance contributes to the pathogenesis of atherosclerotic cardiovascular disease and, thus, has an important impact on the mortality of uraemic patients. Haemodialysis (HD) is known to improve insulin resistance observed in uraemia. However, it is not known whether continuous ambulatory peritoneal dialysis (CAPD) alleviates insulin resistance in adult uraemic patients. The objective of this study was to compare the effect of two different dialysis modalities, HD and CAPD, on insulin resistance in adult uraemic patients and to identify the possible predictive factors for changes in insulin resistance. METHODS: Insulin resistance was examined in 19 non-diabetic patients with end-stage renal disease (ESRD) before and after dialysis therapy (HD, n=10; CAPD, n=9), as well as in 10 healthy controls using the hyperinsulinaemic euglycaemic glucose clamp technique. The glucose disposal rate (GDR mg/kg/min) was used as an index of insulin sensitivity during the clamp technique. We also determined which of various biochemical parameters might be associated with change in insulin resistance by carrying out multiple logistic regression analysis. RESULTS: GDR was significantly lower (6.44+/-1.76) in ESRD subjects than in normal subjects (9.90+/-2.01). HD and CAPD therapies significantly normalized GDR from 6.53+/-1.84 to 9.74+/-2.88 and from 6.35+/-1.65 to 8.18+/-1.76 respectively. Multiple logistic regression analysis showed that changes in BUN, haematocrit and plasma bicarbonate were significant predictive factors for the change in insulin resistance. CONCLUSION: CAPD therapy, in spite of its possible adverse effects in patients with atherosclerotic disease, has been shown to improve insulin resistance in adult uraemic patients, similarly to HD therapy.

Adult↗
PubMed2000

Possible relationship between phototoxicity and photodegradation of sitafloxacin, a quinolone antibacterial agent, in the auricular skin of albino mice.

We compared the phototoxic potential of the quinolone antibacterial agent sitafloxacin with those of lomefloxacin and sparfloxacin. Female BALB/c mice were given a single intravenous administration of sitafloxacin, lomefloxacin, or sparfloxacin at 10 or 40 mg/kg, followed by ultraviolet-A (UVA) irradiation for 4 h (21.6 J/cm(2)). At 10 mg/kg, all quinolones induced either none or minimum inflammation in the auricle. At 40 mg/kg, sitafloxacin induced mild phototoxic inflammation in the dermal skin, while lomefloxacin and sparfloxacin induced very severe inflammation. In particular, 2/5 animals of the lomefloxacin group showed partial necrosis in the dermis and epidermis. We then determined the time course change of sitafloxacin concentrations in serum and auricular tissue by high performance liquid chromatography. Sitafloxacin concentrations in the auricle were markedly decreased under UVA irradiation, whereas those in sera were not affected. Furthermore, we examined the severity of sitafloxacin-induced phototoxicity under varied duration of UVA irradiation. The severity of phototoxicity increased with increasing duration of UVA irradiation, and statistical analysis showed a close correlation between the severity and the decreased area under the drug concentration curve under UVA irradiation (DeltaAUC(auricle)). The severity was decreased with delay in commencement of UVA irradiation, indicating the importance of commencement time of irradiation in the experimental condition of the phototoxicity study. It might be attributed to the decrease in DeltaAUC(auricle) after administration. These results suggest that sitafloxacin possesses milder phototoxic potential than lomefloxacin or sparfloxacin and is degraded in the auricular skin under UVA irradiation, and that the severity of phototoxicity is directly proportional to the DeltaAUC(auricle).

Animals↗
PubMed2000

Investigation of effective anesthesia induction doses using a wide range of infusion rates with undiluted and diluted propofol.

BACKGROUND: The influence of infusion rate on the induction dose-response relation has not been investigated over a wide range of infusion rates. In this study, the authors defined the effect of different propofol infusion rates on the times and doses necessary to reach clinical induction of anesthesia. METHODS: The subjects of the study were 250 patients classified as American Society of Anesthesiologists physical status I or II aged 25-55 yr. For induction with undiluted propofol, 180 patients were allocated randomly to one of two groups of 90 patients each (A and B). Each group was further divided into nine subgroups (10 patients each) that were administered propofol infusion at rates of 10, 15, 20, 30, 40, 60, 100, 200, and 300 mg/kg-1/h-1. The remaining 70 patients (group C) were allocated randomly into seven subgroups (10 patients each), and these groups were induced with diluted propofol (0.5 mg/ ml) at the rates of 10, 15, 30, 60, 100, 200, and 300 mg/kg-1/ h-1. Group B was given crystalloid at the same infusion rates as group C via a catheter in the opposite arm. Induction time, induction dose, plasma arterial propofol concentration at loss of consciousness, and percentage decrease of systolic blood pressure were measured. A previously reported three-compartment model with an effect-site rate constant for propofol of 0.456/min was used to predict the induction time and dose at each infusion rate. RESULTS: The differences between predicted induction time and dose and the observed time and dose could be explained by factoring in the lag time from infusion site to central compartment (lag time circulation) and the amount of propofol in transit during this time (residual dose circulation). Residual dose circulation and lag time circulation correlated with infusion time from 20 to 60 s for undiluted and from 0 to 40 s for diluted propofol. At the infusion rates greater than 80 mg/kg-1/h-1, rapid circulation because of incomplete mixing in the central compartment decreased the excess induction time and dose. The use of diluted propofol significantly attenuated the decrease in systolic blood pressure provoked by the residual dose circulation. CONCLUSIONS: Induction dose and time are dependent on infusion rate in a complex manner, and residual dose circulation was a factor in overdose and hemodynamic depression. Hypotension during induction was attenuated by diluted propofol.

Adult↗
PubMed2000

Optimal propofol plasma concentration during upper gastrointestinal endoscopy in young, middle-aged, and elderly patients.

BACKGROUND: Suitable propofol plasma concentrations during gastroscopy have not been determined for suppressing somatic and hemodynamic responses in different age groups. METHODS: Propofol sedation at target plasma concentrations from 0.5 to 4.0 microgram/ml were performed randomly in three groups of patients (23 per group) who were undergoing elective outpatient gastroscopy: ages 17-49 yr (group 1), 50-69 yr (group 2), and 70-89 yr (group 3). Plasma propofol concentration in which 50% of patients do not respond to these different stimuli were determined by logistic regression: verbal command (Cp50ls), somatic response to gastroscopy (Cp50endo), and gag response to gastroscopy (Cp50gag). Hemodynamic responses were also investigated in the different age groups. RESULTS: Cp50ls concentrations were 2.23 microgram/ml (group 1), 1.75 microgram/ml (group 2), and 1.40 microgram/ml (group 3). The Cp50endo values in groups 1 and 2 were 2.87 and 2.34 microgram/ml, respectively, which were significantly higher than their respective Cp50ls values. Cp50endo value in group 3 was 1.64 microgram/ml, which was close to its Cp50ls value. Because of a high degree of interpatient variability, Cp50gag could not be defined. Systolic blood pressure response decreased with increasing propofol concentrations. CONCLUSIONS: The authors determined the propofol concentration necessary for gastroscopy and showed that increasing age reduces it. Propofol concentration that suppresses somatic response induces loss of consciousness in almost all young patients.

Adolescent↗
PubMed2000

Marked reduction of mortality in salt-loaded Dahl salt-sensitive rats by the new, selective endothelin ETA receptor antagonist, J-105859.

OBJECTIVE: To examine the chronic effects of a newly synthesized, potent and selective endothelin (ET) ETA receptor antagonist, J-1 05859, on mortality in salt-loaded Dahl salt-sensitive (DS) rats and to confirm the potential of this compound as an ETA antagonist METHODS: Vehicle and J-105859 were administered to salt-loaded DS rats for 12 weeks. Throughout the experimental period, blood pressure was measured continuously using a telemetry system and the survival rate was determined. The surviving animals were subsequently sacrificed and autopsy was performed. Binding and functional assays were also carried out to characterize J-1 05859. RESULTS: The Ki values of J-1 05859 for cloned human ETA and ETB were 0.025 and 48 nmol/l, respectively. J-105859 inhibited ET-1-induced contractions in rabbit iliac artery (pA2 = 10.08) and BQ-3020 (ETB agonist)-induced contractions in pulmonary artery (pA2 = 7.63). The pressor response to intravenous (i.v.) ET-1 (0.5 nmol/kg) was significantly inhibited by J-1 05859 at a dose of 0.03 mg/kg i.v. Chronic treatment with J-1 05859 [0.1 and 1 mg/kg per day orally (p.o.)] from the prehypertensive stage decreased the mortality of salt-loaded DS rats and markedly inhibited the development of brain lesions. The survival rates in the control and J-1 05859 (0.1 and 1 mg/kg per day) groups were 34, 80 and 100%, respectively. Development of hypertension was markedly inhibited at a dose of 1 mg/kg per day. CONCLUSION: J-105859 is a selective, potent, orally active ETA-selective antagonist ETA antagonists may reduce morbidity as well as mortality in salt-sensitive hypertension.

Alkanes↗
PubMed2000

Antihypertensive effects of a mixed endothelin-A- and -B-receptor antagonist, J-104132, were augmented in the presence of an AT1 -receptor antagonist, MK-954.

The single oral administration of a mixed endothelin-A-and -B- (ETA/ETB) receptor antagonist, J-104132 (L-753,037) decreased the blood pressure in conscious spontaneously hypertensive rats (SHR), stroke-prone SHR (SHRSP) and Dahl salt-sensitive hypertensive rats fed high-salt diet (DS-H) at doses of 3 and 10 mg/kg, with a duration of approximately 24 h. The magnitude of the antihypertensive effects was greater in DS-H than in SHR and SHRSP Preproendothelin-1 mRNA expression in the kidney and aorta was greater (about twofold) in DS-H than that in nonnotensive Dahl salt-resistant rats fed high-salt diet (DR-H), while there was no difference in preproendothelin-1 mRNA expression between SHR and Wistar Kyoto rats (WKY). An AT1-receptor antagonist, MK-954 (Losartan), also attenuated hypertension in SHR and SHRSP at oral doses of 3 and 10 mg/kg, but bad no effect in DS-H. The concomitant treatment with MK-954 and J-104132 showed additive antihypertensive effects in SHR and SHRSP. In DS-H, MK-954 potentiated the antihypertensive effects of J-104132. From these results, we suggest that: (1) the contribution of endothelin (ET) to the maintenance of hypertension is greater in salt-sensitive hypertensive models than in SHR and SHRSP; (2) the antihypertensive efficacy of ETA/ETB blockade is augmented by AT1-receptor blockade; (3) ET blockers alone or in combination with AT1 antagonists could be useful in the treatment of hypertension for patients who do not respond adequately to renin-angiotensin system inhibitors alone.

Angiotensin Receptor Antagonists↗
PubMed2000

Intravenous low-dose native tissue plasminogen activator for distal embolism in the middle cerebral artery divisions or branches: a pilot study.

OBJECTIVE: We prospectively evaluated the safety and efficacy of an intravenous infusion of low-dose native tissue plasminogen activator for distal embolisms in the middle cerebral artery divisions or branches. METHODS: Twenty patients were selected according to the following computed tomographic and angiographic criteria and treated with intravenous infusion of 7.2 mg of tisokinase: 1) no early ischemic changes on the initial computed tomographic scan, and 2) embolic occlusion of the middle cerebral artery divisions or branches without the involvement of the lenticulostriate arteries. For comparison, the records of 12 patients from previous years who met the above inclusion criteria but underwent no thrombolytic therapy were reviewed retrospectively. The degree of neurological recovery was assessed using the National Institutes of Health Stroke Scale at 24 hours after admission. Major neurological improvement was defined as a decrease in the stroke score by 4 points or more. RESULTS: There was no significant difference in stroke scores at the time of admission between the treatment group (mean +/- standard deviation, 12.8 +/- 2.8) and the untreated group (14.0 +/- 2.4). In the treatment group, major neurological improvement was seen in 17 (85%) of 20 patients, whereas in the untreated group only 5 (41.7%) of 12 patients showed major neurological improvement (P < 0.05). The mean score at 24 hours in the treatment group (3.6 +/- 3.5) was significantly lower than that in the untreated group (9.4 +/- 7.3) (P < 0.05). There was no hemorrhagic complication with neurological exacerbation in the treatment group. CONCLUSION: Even with delayed initiation (>3 h after symptom onset), intravenous infusion of low-dose tisokinase may be safe and effective for small distal emboli in the middle cerebral artery divisions or branches, when early ischemic changes on computed tomographic scans and involvement of the lenticulostriate arteries are absent.

Aged↗
PubMed2000

Thresholds of ischemia salvageable with intravenous tissue plasminogen activator therapy: evaluation with cerebral blood flow single-photon emission computed tomographic measurements.

OBJECTIVE: This study investigated the cerebral blood flow (CBF) thresholds of ischemic cortices that were salvageable with intravenous tissue plasminogen activator (t-PA) infusion therapy. METHODS: We retrospectively reviewed data for 20 patients who were treated with intravenous low-dose (7.2 mg) native t-PA infusion therapy for distal embolic occlusions of middle cerebral artery divisions or branches, without early computed tomographic ischemic changes. All patients underwent pretreatment single-photon emission computed tomographic CBF measurements using (99m)Tc-N,N'-(1,2-ethylenediyl)bis-L-cysteine diethylester. Intravenous t-PA infusion was initiated within 6 hours (average, 3 h) after symptom onset for 14 patients and 6 to 14 hours (average, 8.8 h) after the last time the patient was noted to be in normal condition for the other 6 patients. Pretreatment single-photon emission computed tomographic and 3-month post-treatment computed tomographic scans were compared using computerized coregistration. Ischemic cortices in single-photon emission computed tomographic scans were divided into areas of reversible and irreversible ischemia. The degree of hypoperfusion was analyzed with an asymmetry index (AI). The AI was calculated as C(a)/C(b) x 100%, where C(a) represents the mean reconstructed counts for the ipsilateral ischemic area and C(b) represents the mean reconstructed counts for the corresponding contralateral area. RESULTS: Partial recanalization, with clinical improvement, at 60 minutes was confirmed by angiography for 14 of the 20 patients (70%). Seventeen of the 20 patients (85%) exhibited major neurological improvements (defined as decreases in National Institutes of Health Stroke Scale scores of > or =4 points) at 24 hours, suggesting that recanalization occurred within 24 hours for almost all patients. AIs for the 25 irreversible lesions ranged from 15.0 to 53.4% (37.3 +/- 11.6%), whereas AIs for the 38 reversible lesions ranged from 45.0 to 83.1% (69.3 +/- 8.6%). There was a significant difference in the AIs for these two groups (P < 0.0001). The ischemia in tissue with AIs of more than 53.4% was reversible. In contrast, ischemic tissue with AIs of less than 45.0% could not escape cerebral infarction with our treatment. The ischemia in tissue with AIs between 45.0 and 53.4% was reversible in some patients and irreversible in others. CONCLUSION: To save ischemic tissue with our intravenous t-PA infusion therapy, residual CBF should be at least 45% of the contralateral presumed normal CBF value. CBF thresholds for ischemia that would be surely salvageable with our intravenous t-PA infusion therapy might be approximately 50 to 55% of the contralateral presumed normal CBF values.

Acute Disease↗
PubMed2000

Effects of EPC-K1 on lipid peroxidation in experimental spinal cord injury.

STUDY DESIGN: A study in which levels of lipid peroxidation were measured, the thiobarbituric acid-reactive substances were estimated in an experimental rat model, and the recovery was assessed. OBJECTIVE: To ascertain the occurrence of thiobarbituric acid-reactive substances in the damaged spinal cord, and to investigate the effectiveness of a hydroxyl radical scavenger EPC-K1, a phosphate diester linkage of vitamins E and C, in attenuating the severity of spinal cord injury. SUMMARY OF BACKGROUND DATA: Lipid peroxidation has been reported to play an important role in spinal cord injury. There is no report on the use of EPC-K1 to attenuate the severity of spinal cord injury in either animal or human studies. METHODS: Spinal cord injury was induced by placing a 25-g weight on T12, and the animals were divided into six groups. Group 1 (sham) received only laminectomy. Group 2 (control) received spinal cord injury. Group 3 received EPC-K1 5 minutes before injury. Group 4 received it 5 minutes after injury. Group 5 received it 3 hours after injury. Group 6 received it five times, respectively: at 5 minutes, then 1, 2, 3, and 4 hours after injury. The levels of thiobarbituric acid-reactive substances were measured in the spinal cord, and the recovery was assessed. RESULTS: The thiobarbituric acid-reactive substances content increased after injury, with two peaks, at 1 and 4 hours. Concentration at the 4-hour peak was lower in nitrogen mustard-induced leukocytopenia rats than in the control rats. The EPC-K1 injection reduced thiobarbituric acid-reactive substances content at 1 and 4 hours after injury in Group 3 (respectively, 34.3% and 42.7% vs. control) and only that at 4 hours in Group 6 (24.9% vs. control). Motor function recovery and histologic findings were better in these two groups than in Group 2. CONCLUSION: Repeated injection of EPC-K1 attenuated the severity of spinal cord injury.

Alkylating Agents↗
PubMed2000

Description of Mogibacterium pumilum gen. nov., sp. nov. and Mogibacterium vescum gen. nov., sp. nov., and reclassification of Eubacterium timidum (Holdeman et al. 1980) as Mogibacterium timidum gen. nov., comb. nov.

A new genus, Mogibacterium, is proposed for anaerobic, non-spore-forming, Gram-positive, rod-shaped bacteria which have been isolated from the periodontal pockets of adult human patients with periodontal disease and infected root canals. The novel isolates, strains D2-18T, BA11a-f and D5-2T, were inert in most of the conventional biochemical tests and phenotypically resemble asaccharolytic Eubacterium species. The protein profiles of whole cells on SDS-PAGE gels and Western immunoblotting reaction analysis distinguished these organisms from type strains belonging to the previously described Eubacterium species. The G + C content of the DNA is 45-46 mol% for Mogibacterium pumilum and 46 mol% for Mogibacterium vescum. The levels of DNA-DNA relatedness of these new species to other Eubacterium species, including Eubacterium limosum, Eubacterium brachy, Eubacterium lentum, Eubacterium nodatum, Eubacterium saphenum, and the more recently proposed Eubacterium minutum and Eubacterium exiguum (reclassified as Slackia exigua), are less than 2%. The DNA-DNA hybridization value between M. pumilum and M. vescum was 30%. Eubacterium timidum exhibited DNA homologies with Mogibacterium species which were low (17 and 18%) but clearly higher than with all the other Eubacterium species. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the closest phylogenetic neighbour of Mogibacterium species was E. timidum, and that these three species represent a novel lineage distinct from the previously described genera of Gram-positive, rod-shaped bacteria. On the basis of phenotypic characteristics and 16S rRNA gene sequence comparisons, it is also proposed that E. timidum is transferred to the genus Mogibacterium gen. nov. as Mogibacterium timidum gen. nov., comb. nov. (type strain ATCC 33093T).

Adult↗
PubMed2000

Detection of lymphocytes productively infected with Epstein-Barr virus in non-neoplastic tonsils.

Epstein-Barr virus (EBV) persists for life in the infected host. Little is known about EBV reactivation and regulation of virus persistence in healthy individuals. We examined tonsils of chronic tonsillitis patients to detect EBV transcripts, EBV genomes and lytic proteins. LMP1 transcripts were observed in 11 of 15 specimens and BZLF1 transcripts were detected in six. Multiple copies of EBV genome equivalents per cell, and ZEBRA- and viral capsid antigen-positive cells were also detected in tonsillar lymphocytes. These results indicate that EBV productively infected cells may survive in the face of immune surveillance in the tonsils. Thus, EBV replication may occur in tonsillar lymphocytes, and tonsillar lymphoid tissues may play a role in the maintenance of EBV load in vivo.

DNA, Viral↗
PubMed2000

Lack of modification by environmental estrogenic compounds of thyroid carcinogenesis in ovariectomized rats pretreated with N-bis(2-hydroxypropyl)nitrosamine (DHPN).

The effects of environmental estrogenic compounds, soy isoflavone mixture (SI), genistein (GEN), and nonylphenol (NP), and the possible goitrogen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), on thyroid carcinogenesis were investigated in ovariectomized (OVX) female rats. Five-week-old OVX F344 rats were given a single subcutaneous injection of N-bis(2-hydroxypropyl)nitrosamine (DHPN; 2400 mg / kg, body weight) or vehicle alone. Starting 1 week later, GEN (250 or 25 ppm in diet), SI (400 ppm in diet), NP (250 or 25 ppm in diet), MX (30 ppm, in drinking water), sulfadimethoxine (SDM), a known thyroid tumor-promoter (1000 ppm in drinking water), or beta-estradiol 3-benzoate (EB), a synthetic estrogen (0.5 mg in cholesterol pellet, s.c.) were administered for 12 weeks. SDM and EB were included as positive controls. At sacrifice the major organs including the thyroid, pituitary, liver, kidney, uterus, vagina, brain and pancreas were collected and histopathological observation was performed. Thyroid weights were significantly increased (P < 0. 001) only in the SDM treatment group and pituitary weights were elevated with SDM (P < 0.05) and EB (P < 0.001). Kidney and uterus weights were also significantly increased (P < 0.05) by EB. Histopathologically, proliferative lesions of the thyroid were only observed in the SDM treatment group and of the pituitary in the SDM or EB treatment groups. Renal tubule lesions, uterine squamous metaplasia, vaginal keratinization and telangiectasia of pancreatic islets were also observed with EB. There were no organ weight changes or histopathological lesions in the major organs, including the thyroid, in the GEN, SI, MX or NP treatment groups. Our results thus indicated a lack of modifying effects on thyroid carcinogenesis in female OVX rats, in agreement with our previous finding in males.

Aminoacridines↗
PubMed2000

Lack of modifying effects of environmental estrogenic compounds on the development of thyroid proliferative lesions in male rats pretreated with N-bis(2-hydroxypropyl)nitrosamine (DHPN).

The modifying effects of various environmental estrogenic compounds on thyroid carcinogenesis were investigated in a rodent two-stage carcinogenesis model. The compounds examined were a soy isoflavone mixture (SI) and genistein (GEN) as phytoestrogens, nonylphenol (NP) as a xenoestrogen, 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) as a thyroid carcinogen and sulfadimethoxine (SDM) as a known thyroid tumor promoter. Five-week-old male F344 rats were given a single subcutaneous injection of N-bis(2-hydroxypropyl)nitrosamine (DHPN; 2800 mg / kg, body weight) or the vehicle alone. Starting one week thereafter, GEN (250 or 25 ppm in diet), SI (400 ppm in diet), NP (250 or 25 ppm in diet), MX (30 ppm, in drinking water) or SDM (1000 ppm in drinking water) was administered for 12 weeks. Major organs including the thyroid, pituitary, liver, kidney, testis, brain and pancreas were weighed and histopathological observation was performed. Thyroid weights were significantly increased (P < 0.001) only in the SDM treatment groups, especially with DHPN pretreatment. Kidney weights were slightly increased in the NP or MX treatment groups, albeit without statistical significance. Histopathologically, thyroid proliferative lesions were only observed in the SDM alone or DHPN + SDM group with significant focal hyperplasias, adenomas and adenocarcinomas limited to the combined treatment case. There were no organ weight changes or histopathological lesions in the major organs including the thyroid in the GEN, SI, NP, and MX treatment groups regardless of DHPN pretreatment. Our results thus indicate that the weakly estrogenic compounds GEN, SI and NP and the environmental rat thyroid carcinogen MX do not exert any modifying effects on thyroid carcinogenesis in rats under the present experimental conditions.

Animals↗
PubMed2000

Antepartum evaluation of monochorionic diamniotic (MD) twins; MD-twin score: a new scoring method for perinatal outcome.

OBJECTIVE: Our purpose was to establish a new scoring method to survey monochorionic diamniotic (MD) twins during antepartum periods. STUDY DESIGN: A retrospective study was performed regarding MD twins delivered between January 1992 and July 1996. Maternal and neonatal records were assessed for the following 5 perinatal variables; birth-weight discordance, amniotic-fluid discordance, hydrops fetalis, umbilical-cord insertion, and fetal-heart-rate monitoring. Each variable was coded as normal or abnormal and then assigned an arbitrary weight of 0 if normal and 1 if abnormal, yielding a range of scores from 0 (all normal) to 5 (all abnormal). The relationships between individual variables and their combinations and the outcome of pregnancy was determined. A poor pregnancy outcome consisted of intrauterine death, neonatal death, or neurological sequelae of at least one twin. The 5-variable combination was termed as the MD-twin score. A chi-square test and logistic regression analysis were used to determine statistical significance. RESULTS: There were 59 MD pregnancies, of which 13 pregnancies resulted in a poor outcome. The single variable that most likely contributed to a poor outcome was amniotic-fluid discordance. All 35 pregnancies with an MD-twin score of < or = 2 had a good outcome. There were 14 pregnancies with a score of 3, and 21% of them had a poor outcome. All of the pregnancies with a score of > or = 4 had a poor outcome. When we chose the MD-twin score of 3 as the critical point for a poor outcome, the likelihood ratio statistics became the highest of any single variable or any combination of variables. CONCLUSION: The MD-twin score predicted poor outcomes better than did any single variable or combination of variables.

Amniotic Fluid↗
PubMed2000

Involvement of an extracellular protease in algicidal activity of the marine bacterium Pseudoalteromonas sp. strain A28.

The marine bacterium Pseudoalteromonas sp. strain A28 was able to kill the diatom Skeletonema costatum strain NIES-324. The culture supernatant of strain A28 showed potent algicidal activity when it was applied to a paper disk placed on a lawn of S. costatum NIES-324. The condensed supernatant, which was prepared by subjecting the A28 culture supernatant to ultrafiltration with a 10,000-M(w)-cutoff membrane, showed algicidal activity, suggesting that strain A28 produced extracellular substances capable of killing S. costatum cells. The condensed supernatant was then found to have protease and DNase activities. Two Pseudoalteromonas mutants lacking algicidal activity, designated NH1 and NH2, were selected after N-methyl-N'-nitrosoguanidine mutagenesis. The culture supernatants of NH1 and NH2 showed less than 15% of the protease activity detected with the parental strain, A28. The protease was purified to homogeneity from A28 culture supernatants by using ion-exchange chromatography followed by preparative gel electrophoresis. Paper-disk assays revealed that the purified protease had potent algicidal activity. The purified protease had a molecular mass for 50 kDa, and the N-terminal amino acid sequence was determined to be Ala-Thr-Pro-Asn-Asp-Pro. The optimum pH and temperature of the protease were found to be 8.8 and 30 degrees C, respectively, by using succinyl-Ala-Ala-Pro-Phe-p-nitroanilide as a substrate. The protease activity was strongly inhibited by phenylmethylsulfonyl fluoride, diisopropyl fluorophosphate, antipain, chymostatin, and leupeptin. No significant inhibition was detected with EDTA, EGTA, phenanthroline or tetraethylenepentamine. These results suggest that Pseudoalteromonas sp. strain A28 produced an extracellular serine protease which was responsible for the algicidal activity of this marine bacterium.

Amylases↗