Biomedical subjects

K Fujiwara

Publications and source records attributed to K Fujiwara.

At least 199 records · Page 11Linked to original sources

PubMed1999

Expression of MAGE-1 and -3 genes and gene products in human hepatocellular carcinoma.

MAGE gene family encodes peptides recognized by autologous cytotoxic T lymphocytes in a major histocompatibility complex (MHC) class-I restricted fashion. In the present study, we have performed reverse-transcription polymerase chain reaction (RT-PCR) for the genes, as well as immunohistochemical analysis and Western blotting of MAGE-1 and -3 proteins in 33 surgically resected hepatocellular carcinomas (HCCs). MAGE-1 and -3 mRNAs were constitutively expressed exclusively in 78 and 42% of HCCs respectively. On immunohistochemistry with monoclonal antibodies, 77B for MAGE-1 and 57B for MAGE-3, MAGE-1 and -3 proteins were recognized in cytoplasm of only six among 33 (18%) and two of 29 HCCs (7%) respectively. The distribution pattern was mostly focal in HCC nodules. By contrast, the Western blot analysis revealed that the MAGE-1 (46 kDa) and -3 proteins (48 kDa) were expressed in 80 and 60% of 15 HCCs examined respectively. The proteins of MAGE-1 and -3 were also expressed exclusively in HCCs regardless of the histological grading and clinical staging. Our results indicate that the detection of the genes by RT-PCR or the proteins by Western blotting is useful for differentiating early HCCs from non-cancerous lesions, and that the peptides derived from MAGE-1 and -3 proteins might be suitable targets for immunotherapy of human HCC.

Adult↗

PubMed1999

Association of Fc gamma receptor IIIB, but not of Fc gamma receptor IIA and IIIA polymorphisms with systemic lupus erythematosus in Japanese.

Human Fc gamma receptor (Fc gamma R) genes form a clustered gene family on chromosome 1q21-24. Although the association of Fc gamma R polymorphisms with systemic lupus erythematosus (SLE) has been extensively studied, the results are often contradictory. In this study, Fc gamma RIIA-131H/R, Fc gamma RIIIA-176F/V and Fc gamma RIIIB-NA1/2 genotypes were determined in the Japanese patients with SLE (n = 81) or rheumatoid arthritis (RA, n = 115) as well as in healthy individuals (n = 217), and possible association with the disease was tested using case-control analysis. Unlike in other populations, significant difference was not observed in the frequencies of Fc gamma RIIA and Fc gamma RIIIA genotypes between patients with SLE and healthy individuals. However, significant difference was detected in the frequencies of Fc gamma RIIIB genotypes between SLE and healthy individuals (P = 0.008). The odds ratio [OR] of the Fc gamma RIIIB-NA2/NA2 homozygotes for the development of SLE was 2.52 (95% confidence interval [CI]: 1.33-4.79). Among the patients with SLE, individuals with NA2/2 were significantly more likely to have lupus nephritis (P = 0.007). No association was observed between any of the Fc gamma R polymorphisms and RA. Significant linkage disequilibrium was detected between Fc gamma RIIIA and IIIB, but neither between IIA and IIIA, nor between IIA and IIIB. These observations may underscore the relevance of defective immune complex handling in the pathogenesis of SLE, or may suggest the presence of primarily associated gene(s) in linkage disequilibrium with Fc gamma R genes.

Adolescent↗

PubMed1999

Molecular cloning, structural characterization and chromosomal localization of human lipoyltransferase gene.

Lipoyltransferase catalyzes the transfer of the lipoyl group from lipoyl-AMP to the lysine residue of the lipoate-dependent enzymes. We isolated human lipoyltransferase cDNA and genomic DNA. The cDNA insert contained a 1119-base pair open reading frame encoding a precursor peptide of 373 amino acids. Predicted amino acid sequence of the protein shares 88 and 31% identity with bovine lipoyltransferase and Escherichia coli lipoate-protein ligase A, respectively. Northern blot analyses of poly(A)+ RNA indicated a major species of about 1.5 kb. mRNA levels of lipoyltransferase were highest in skeletal muscle and heart, showing good correlation with those of dihydrolipoamide acyltransferase subunits of pyruvate, 2-oxoglutarate and branched-chain 2-oxo acid dehydrogenase complexes and H-protein of the glycine cleavage system which accept lipoic acid as a prosthetic group. The human lipoyltransferase gene is a single copy gene composed of four exons and three introns spanning approximately 8 kb of genomic DNA. Some alternatively spliced mRNA species were found by 5'-RACE analysis, and the most abundant species lacks the third exon. The human lipoyltransferase gene was localized to chromosome band 2q11.2 by fluorescence in situ hybridization.

Acyltransferases↗

PubMed1999

The amino-terminal region of the Escherichia coli T-protein of the glycine cleavage system is essential for proper association with H-protein.

T-protein is a component of the glycine cleavage system and catalyzes the tetrahydrofolate-dependent reaction. Our previous work on Escherichia coli T-protein (ET) showed that the lack of the N-terminal 16 residues caused a loss of catalytic activity [Okamura-Ikeda, K., Ohmura, Y., Fujiwara, K. and Motokawa, Y. (1993) Eur. J. Biochem. 216, 539-548]. To define the role of the N-terminal region of ET, a series of deletion mutants were constructed by site-directed mutagenesis and expressed in E. coli. Deletions of the N-terminal 4, 7 and 11 residues led to reduction in the activity to 42, 9 and 4%, respectively, relative to the wild-type enzyme (wtET). The mutant with 7-residue deletion (ETDelta7) was purified and analyzed. ETDelta7 exhibited a marked increase in Km (25-fold) for E. coli H-protein (EH) accompanied by a 10-fold decrease in kcat compared with wtET, indicating the importance of the N-terminal region in the interaction with EH. The role of this region in the ET-EH interaction was investigated by cross-linking of wtET-EH or ETDelta7-EH complex with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, a zero-length cross-linker, in the presence of folate substrates. The resulting tripartite cross-linked products were cleaved with lysylendopeptidase and V8 protease. After purification by reversed-phase HPLC, the cross-linked peptides were subjected to Edman sequencing. An intramolecular cross-linking between Asp34 and Lys216 of wtET which was not observed in wtET alone and an intermolecular cross-linking between Lys288 of wtET and Asp-43 of EH were identified. In contrast, no such cross-linking was detected from the cross-linked product of ETDelta7. These results suggest that EH, when it interacts with ET, causes a change in conformation of ET and that the N-terminal region of ET is essential for the conformational change leading to the proper interaction with EH.

Amino Acid Oxidoreductases↗

PubMed1999

The effect of electrolyzed strong acid aqueous solution on hemodialysis equipment.

We reported the high effectiveness of electrolyzed strong acid aqueous solution (ESAAS) in cleaning hemodialysis lines. Although ESAAS has a strong bactericidal action, one concern is its strong acidity. It has a pH of 2.3-2.7, more than 1,000 mV in oxidation-reduction potential (ORP), and 10-50 ppm of available chlorine. The possibility of metal corrosion, degradation of synthetic resins, chorine gas emission, or dissolving calcium carbonate (CaCO3) deposits due to ESAAS's acidity was tested using in vitro experiments. The bactericidal and antiviral effects of various ESAAS's were also tested. Metal corrosion and synthetic resin degradation, although they occurred, were not serious. There were no problems with chlorine gas emission and dissolving of CaCO3 deposits. Each type of ESAAS showed almost the same bactericidal and antiviral effect, but in some cases differences were observed.

Acetic Acid↗

PubMed1999

The cleaning and disinfecting of hemodialysis equipment using electrolyzed strong acid aqueous solution.

In general, sodium hypochlorite, formalin, and Dialox (Teijin Gambro Medical, Ltd., Tokyo, Japan [main ingredients: H2O2, CH3CHOOOH, CH3COOH, H2O]) are used to clean and disinfect hemodialysis pipelines. In this study, the suitability of electrolyzed strong acid aqueous solution (ESAAS), which has attracted considerable interest in Japan because of its strong disinfecting properties, was examined. The crossover method was used to investigate the effectiveness of ESAAS in disinfecting the dialysis pipelines in comparison to that of sodium hypochlorite (200 ppm) used alternately with 1% acetic acid. The number of bacteria and the concentration of endotoxin (Et) were measured over an approximately 3 year period, starting in September 1994. Until then, 200 ppm sodium hypochlorite had been used alternately with 1% acetic acid, and the contamination of the pipeline had been marked. However, after switching to the ESAAS disinfection method, the dialysis pipelines very rapidly became cleaner. Therefore, the decision to develop an automated ESAAS cleaning system for long-term use was made. During the development period, the original disinfectants (200 ppm sodium hypochlorite used alternately with 1% acetic acid) were used as a stopgap. After confirmation of its performance and safety, the automated ESAAS cleaning system was introduced. To find out whether the decrease in bacteria secondarily caused a decrease in the Et concentration or whether the ESAAS directly inactivated the Et, an in vitro experiment was carried out. Highly concentrated Et, which had been left in the reverse osmosis (RO) drainage pipeline, was used as a sample to investigate the effects of ESAAS on Et at various concentrations and temperatures and on the recovery test. The results showed that ESAAS directly inactivated Et. This paper reports the results of the crossover test. The results of parallel tests carried out over an approximately 4 year period have already been reported. No significant problems occurred in the dialysis. The automated ESAAS cleaning system that was developed proved to be more economical than the conventional disinfecting method.

Acetic Acid↗

PubMed1999

Increased urinary phosphate excretion in pseudohypoparathyroidism type II with long-term treatment with phosphodiesterase inhibitor.

A 58-year-old woman was diagnosed to have pseudohypoparathyroidism (PHP) type II because of the absence of an increase of urinary phosphate secretion, despite a marked increase in urinary cAMP excretion on the Ellsworth-Howard test. We treated the patient with a cyclic-nucleotide phosphodiesterase inhibitor, theophylline, resulting in increased urinary phosphate and cAMP excretions. Dibutyl cAMP administration induced the increase in the urinary phosphate excretion. In this case, the unresponsiveness of the urinary phosphate secretion to cAMP was recovered by a high dose of cAMP or long-term administration of a phosphodiesterase inhibitor. These data imply that cAMP responsiveness to renal tubular phosphate reabsorption should be more strictly elucidated in the patient with PHP type II.

Bucladesine↗

PubMed1999

Histamine monoclonal antibody for brain immunocytochemistry.

Among five monoclonal antibodies (AHA-1 to 5 mAbs) prepared against glutaraldehyde (GA)-conjugated histamine (HA) in our previous study, only mAb AHA-2 was found to detect HA specifically in rat brain neurons by an immunocytochemistry method (ICC) using GA as a tissue fixative. All the other mAbs, except for AHA-5, reacted with HA in the enterochromaffin-like cells (ECL cells) of rat stomach [Fujiwara et al. (1997) Histochem. Cell Biol. 107, 39-45]. Enzyme-linked immunosorbent assay (ELISA) binding and inhibition tests demonstrated that AHA-2 is specific for HA, with almost no detectable cross-reaction with any other established or putative amino acid neurotransmitters, LH-RH, TRH, or peptides with N-terminal histidines. ELISA assays also suggested that the AHA-2 mAb recognizes a HA epitope structure different from the one recognized by the AHA-1 mAb. The immunostaining patterns with AHA-2 mAb, as seen in the five subgroups of the tuberomammillary nuclei in the rat posterior hypothalamus, were very similar to those described by Inagaki et al. [(1988) Brain Res. 439, 402-405; (1990) Exp. Brain Res. 80, 374-380] and Panula et al. [(1984) Proc. Natl. Acad. Sci. USA 81, 2572-2576; (1988) J. Histochem. Cytochem. 36, 259-269] using polyclonal anti-HA serum. However, it was also noted that moderate numbers of immunoreactive nerve fibers projected into the median eminence. The present HA ICC method using AHA-2 mAb allows highly sensitive HA detection in brain, and thus might permit detailed studies of HA localization hitherto impossible using previously available anti-HA polyclonal antibodies produced against carbodiimide-conjugated HA.

Animals↗

PubMed1999

Glutaraldehyde (GA)-hapten adducts, but without a carrier protein, for use in a specificity study on an antibody against a GA-conjugated hapten compound: histamine monoclonal antibody (AHA-2) as a model.

In our recent study on monoclonal antibodies (mAbs AHA-1-5) against glutaraldehyde (GA)-conjugated histamine (HA), we identified one mAb (AHA-2) which can detect neuronal HA in the rat brain with an immunocytochemistry method (ICC) [Fujiwara et al. (1999) J. Biochem. 126, 503-509]. In the present study the specificity of AHA-2 mAb for use for ICC has been examined by means of competitive experiments involving HA and analogs, all of which had been allowed to react with GA followed by sodium borohydride, but not allowed to couple with the carrier protein. It was demonstrated that the antibody distinguished alterations in the chemical structure of the molecule, showing decreased immunoreactivity with all the GA-adducts of (R)-(-)-alpha-methylhistamine, 1- and 3-methylhistamine, L-histidine, and 1- and 3-methyl-L-histidine. On the other hand, AHA-1 mAb only reacted with GA-adducts of 3-MeHA (3-MeHA-GA) and HA (HA-GA), to almost the same degree, in relatively high concentration ranges. AHA-3, 4, and 5 mAbs reacted about 10-times more strongly with 1-MeHA-GA than with HA-GA, but reacted very little or not at all with the other analogs. These results may suggest that AHA-2 mAb recognized both the non-substituted imidazole and alpha-methine groups of a HA molecule in addition to the conjugation site of GA including the part(s) reduced with NaBH(4), and especially the imidazole group more strictly than the other mAbs. This may partly explain why AHA-2, among the five AHA mAbs, can detect neuronal HA with an ICC method. The present ELISA method for GA-hapten adducts should be applicable to other antibodies against GA-conjugated biologically active amines or amino acids, thus allowing the study of antibody specificity for ICC more easily and accurately than was previously possible with hapten-protein conjugates as antigens.

Animals↗

PubMed1999

Clinical results of transcatheter arterial infusion for uterine cervical cancer.

The effects of transcatheter intraarterial infusion of anticancer drugs on the prognosis of cervical cancer were retrospectively studied. Two or three sessions of transcatheter arterial infusion therapy were performed for 68 patients with primary uterine cervical cancer. The number of patients with stage I, II, III, or IV disease were 13, 22, 24, and 9, respectively. Patients with squamous cell carcinoma comprised 3, 17, 17, and 5 of the respective groups, and the patients with stage I and II disease had either adenocarcinoma or adenosquamous carcinoma, or bulky tumor (>4 cm). The drugs infused were cisplatin (60-70 mg/m2), doxorubicin hydrochloride (30-40 mg/m2), mitomycin (15 mg/m2), and 5-fluorouracil (500 mg/body). They were infused via the bilateral internal iliac arteries. Fifty-eight of the 68 patients (85%) received a radical hysterectomy after transcatheter arterial infusion: 12 of 13 with stage I disease, 21 of 22 with stage II disease, 20 of 24 with stage III disease, and five of nine with stage IV disease. Two patients with stage III disease received radical radiotherapy. The other eight patients (one with stage I disease, one with stage II disease, two with stage III disease, and four with stage IV disease) did not receive an operation after transcatheter arterial infusion because they had distant metastases at the time of operation. Thirty-two of 58 patients (56%) received postoperative radiotherapy. The complete histologic response rates (no active cancer cells) after transcatheter arterial infusion were: 2 of 12 patients with stage I disease, 3 of 21 patients with stage II disease, 5 of 20 patients with stage III disease, and one of five patients with stage IV disease. Tumors with squamous cell carcinoma disappeared at a significantly better rate (10/36, 28%) than did tumors with adenocarcinoma or adenosquamous cell carcinoma (1/22, 5%; p < 0.05). The overall 5-year survival rates of the patients with stages I, II, and III disease were 92.3%, 62.2%, and 71%, respectively. The 5-year survival rates of the patients who underwent surgery with stage I, II, and III disease were 100%, 66.3%, and 71.5%, respectively. Leukocytopenia and thrombocytopenia occurred as an acute complication in 75% and 79% of the patients, respectively. As a late complication, ileus occurred in 7%. Transcatheter arterial infusion may improve the prognosis of patients with cervical cancer without increasing the incidence of late complications.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1999

Renal afferent and efferent arteriolar dilation by nilvadipine: studies in the isolated perfused hydronephrotic kidney.

Although calcium antagonists are believed to exert preferential vasodilator action on the renal preglomerular afferent arteriole, we recently demonstrated that efonidipine, a novel calcium antagonist, vasodilates both afferent and efferent arterioles. Nilvadipine also is reported to increase renal blood flow and reduce filtration fraction, suggesting indirectly afferent and efferent arteriolar vasodilation. No direct investigation, however, has been conducted examining the renal microvascular action of nilvadipine. We therefore characterized the renal microvascular reactivity to nilvadipine, by using the isolated perfused rat hydronephrotic kidney. The administration of angiotensin II (0.3 nM) caused marked vasoconstriction of afferent (from 13.5 +/- 0.6 to 9.2 +/- 0.6 microm, p < 0.01, n = 6) and efferent arterioles (from 11.5 +/- 1.0 to 7.4 +/- 0.7 microm, p < 0.01; n = 5). The subsequent addition of nilvadipine (10 nM, 100 nM, and 1 microM) caused 37 +/- 5%, 91 +/- 4%, and 95 +/- 8% reversal of afferent arteriolar constriction, respectively. Similarly, efferent arterioles manifested 59 +/- 12% reversal by 1 microM nilvadipine. Thus unlike nifedipine, which we previously reported to cause modest efferent arteriolar dilation (21 +/- 1% reversal at 1 microM), nilvadipine possesses the greater ability to dilate efferent arterioles (p < 0.01 vs. nifedipine), although both antagonists cause similar magnitudes of afferent arteriolar vasodilation. Variable effects on the efferent arteriole suggest the heterogeneity in the calcium antagonist with regard to the renal microvascular action of this agent.

Anesthesia↗

PubMed1999

Supernumerary ovary found by ultrasonogram and FSH measurement after an extensive operation for a yolk sac tumor of the ovary.

A rare case of supernumerary ovary found by a transvaginal ultrasonogram and follicle-stimulating hormone (FSH) measurement is presented. The patient was a 32-year-old female who underwent an extensive operation for a yolk sac tumor of the ovary. An asymptomatic cystic tumor was found during follow-up. There was no evidence of recurrence or metastasis of the yolk sac tumor. Although histological confirmation was not possible because the patient refused removal of the mass, a diagnosis of supernumerary ovary was made because changes in the shape of the cystic mass completely correlated with changes in the serum FSH level.

Adult↗

PubMed1999

Determination of granulocyte-specific antigens on neutrophil FcA receptor IIIb by PCR-preferential homoduplex formation assay, and gene frequencies in the Japanese population.

BACKGROUND AND OBJECTIVES: Granulocyte-specific antigens play an important role in provoking immune neutropenia and transfusion reactions. We developed a new DNA-typing method, PCR-preferential homoduplex formation assay (PHFA), to determine granulocyte-specific antigens on the neutrophil Fcgamma receptor IIIb (FcgammaRIIIb, CD16b), namely, the NA1, NA2, and SH antigens and their gene frequencies in the Japanese population. MATERIALS AND METHODS: Four hundred unrelated healthy Japanese blood donors were typed using PCR-PHFA. To confirm the accuracy of the results of FcgammaRIIIB genotyping using PCR-PHFA, PCR-sequence-specific primer (SSP) typing and PCR-restriction fragment length polymorphism (RFLP) typing were carried out in another 20 samples for comparison. RESULTS: The results of PCR-PHFA typing agreed well with other methods. The frequencies of the FcgammaRIIIB alleles were 62.2, 37.8, 0 and 0% for NA1, NA2, SH, and 'NA-null', respectively. CONCLUSION: The PCR-PHFA method can be semi-automated easily with computer-based assignment and is suitable for typing both small and large numbers of samples. In the Japanese population, the frequency of NA1 is about double that in Caucasians (32.5%), and the SH allele is rare.

Alleles↗

PubMed1999

Altered pressure-natriuresis in obese Zucker rats.

It has not been examined whether the pressure-natriuresis response is altered in the insulin-resistant condition. Furthermore, despite an important role of nitric oxide (NO) in modulating pressure-natriuresis, no investigations have been conducted assessing the renal interstitial NO production in insulin resistance. The present study examined whether pressure-natriuresis was altered in insulin-resistant obese Zucker rats (OZ) and assessed the cortical and medullary nitrate/nitrite (NOx) levels with the use of the renal microdialysis technique. In OZ, serum insulin/glucose ratio (23.0+/-4.0x10(-8), n=9) and blood pressure (119+/-3 mm Hg) were greater than those in lean Zucker rats (LZ; 7.0+/-1.9x10(-8) and 103+/-4 mm Hg, n=9). The pressure-natriuresis curve in OZ was shifted to higher renal perfusion pressure (RPP), and the slope was blunted compared with that in LZ (0.073+/-0.015 vs 0.217+/-0.047 microEq/min kidney weight/mm Hg, P<0.05). The basal renal NOx level was reduced in OZ (cortex, 4.032+/-0.331 micromol/L; medulla, 4. 329+/-0.515 micromol/L) compared with that in LZ (cortex, 7.315+/-1. 102 micromol/L; medulla: 7.698+/-0.964 micromol/L). Furthermore, elevating RPP increased the medullary NOx in LZ, but this pressure-induced response was lost in OZ. Four-week treatment with troglitazone, an insulin-sensitizing agent, improved hyperinsulinemia, systemic hypertension, and basal renal NOx levels (cortex, 5.639+/-0.286 micromol/L; medulla, 5.978+/-0.284 micromol/L), and partially ameliorated the pressure-natriuresis curves; the slope of pressure-natriuresis curves and elevated RPP-induced NOx, however, were not corrected. In conclusion, our study suggests that insulin resistance is closely associated with abnormal pressure-natriuresis and hypertension. These deranged renal responses to insulin resistance are most likely attributed to impaired medullary NO production within the medulla.

Animals↗

PubMed1999

Immunocytochemical localization of histamine in enterochromaffin-like (ECL) cells in rat oxyntic mucosa: a transmission electron microscopy study using monoclonal antibodies and conventional glutaraldehyde-based fixation.

Histamine (HA), contained in the enterochromaffin-like (ECL) cells of the gastric mucosa in animals, plays an important role in gastric acid secretion, although methods for its exact morphological localization are still lacking. We used a pre-embedding indirect immunoperoxidase approach to define the fine structural localization of HA in rat oxyntic mucosa that was fixed with a glutaraldehyde-based fixative and HA monoclonal antibodies (MAbs AHA-1 and 2). Transmission electron microscopy showed that the peroxidase endproduct not only was concentrated in the cores of cytoplasmic granules but also was distributed to a high degree in the cytoplasm peripheral to the granules of the ECL cells. These results suggest that in ECL cells HA is enzymatically synthesized in the cytoplasm, then is transported and stored in the cores of the granules before its release from the basal lamina. The present HA immunoelectron microscopic method with MAbs would be applicable more generally to the ultrastructural identification of HA-containing cells.

Animals↗

PubMed1999

Immunocytochemical localization of prolactin-releasing peptide in the rat brain.

A hypothalamic peptide that stimulates PRL release has recently been found as a ligand of an orphan receptor and named PRL-releasing peptide (PrRP). PrRP and its receptor were mainly detected in the hypothalamus and pituitary gland, respectively. Its characteristics suggested PrRP to be a novel hypophysiotropic peptide that stimulates the anterior pituitary PRL cell; however, this remained to be confirmed morphologically. We therefore performed an immunocytochemical study to locate PrRP in the rat brain using the region-specific monoclonal antibodies, P2L-1C and P2L-1T, which recognize the C-terminal and the internal sequence of PrRP, respectively. Our results clearly show that dense immunoreactive nerve fiber networks are present in the paraventricular hypothalamic nucleus, supraoptic nucleus, paratenial thalamic nucleus, basolateral amygdaloid nucleus, and bed nucleus of the stria terminalis. A small number of PrRP nerve fibers was also observed in the neural lobe of the hypophysis. However, no immunopositive fiber was observed in the external region of the median eminence, which is known to be the release site of the classical hypophysiotropic hormones. Also, the distribution of PrRP was not changed during the estrous cycle. We therefore concluded that PrRP probably differs from classical hypothalamic releasing hormones. We found the immunoreactive cell bodies to be mainly in the caudal portion of the dorsomedial hypothalamic nucleus and solitary nucleus. A double immunocytochemical procedure revealed that some PrRP-positive neurons showed synaptic contact with oxytocin-positive cell bodies in the paraventricular hypothalamic nucleus, which suggests that PrRP regulates the function of oxytocin neurons. This is the first report to demonstrate the localization of the novel hypothalamic peptide, PrRP, and we therefore suggest that it takes part in a variety of brain functions. However, it is not yet known how PrRP is transported to the pituitary gland, which is the site that contains the greatest concentration of receptors to this new peptide. Therefore, additional work will be required to resolve this discrepancy between ligand and receptor site location.

Animals↗

PubMed1999

Impaired nitric oxide-independent dilation of renal afferent arterioles in spontaneously hypertensive rats.

Sustained hypertension alters vasomotor regulation in various vascular beds. We studied whether nitric oxide (NO)-dependent and NO-independent vasodilator mechanisms are altered in renal microvessels in hypertension. To directly visualize the renal microcirculation, the isolated perfused hydronephrotic rat kidney model was used. After pretreatment with indomethacin (100 micromol/l), afferent arterioles were constricted by norepinephrine (NE) or by increasing renal arterial pressure (i.e., myogenic constriction; from 80 to 180 mmHg). Acetylcholine (ACH) was then added, and the renal microvascular response was assessed by computer-assisted video image analysis. A similar protocol was conducted in the presence of nitro-L-arginine methylester (L-NAME; 100 micromol/l). During NE constriction, ACH caused dose-dependent and sustained vasodilation of the afferent arteriole, similar in magnitude in Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). In the presence of L-NAME, ACH (0.01-1 micromol/l) elicited only transient dilation, and the degree of vasodilation was very low in SHR. During myogenic constriction, afferent arterioles from WKY and SHR kidneys responded to ACH with only transient vasodilation, which was unaffected by NO inhibition; the transient vasodilative responses elicited by ACH (0.1-1 micromol/l) were smaller in SHR than in WKY. In conclusion, ACH has both sustained and transient vasodilative effects on the afferent arteriole. Sustained vasodilation is attributed to NO generation, which is similar in WKY and SHR. In contrast, transient vasodilation, mediated by NO-independent vasodilator factors, is impaired in SHR. Deranged vasodilatory mechanisms in hypertension may disturb the renal microcirculation, which may result in renal injury.

Acetylcholine↗

PubMed1999

Naturally occurring Tyzzer's disease in a calf.

Naturally occurring Clostridium piliforme infection (Tyzzer's disease) was found in a calf. Light microscopic examination revealed multifocal coagulative necrosis in the liver, catarrhal gastroenteritis, tracheitis and pneumonia, and thymic atrophy. Warthin-Starry staining clearly showed large filamentous bacilli in bundles or criss-cross patterns within the hepatocytes and epithelium and smooth muscle cells of the ileum and cecum. Immunohistochemistry using anti-C. piliforme RT and MSK strain antisera showed positive reaction against the bacilli. Electron microscopic examination revealed bacilli within the hepatocytes that demonstrated a characteristic vegetative form, with peritrichous flagella, and spores. The polymerase chain reaction (PCR) study using the paraffin-embedded liver sections, the 196-bp DNA fragment specific to 16S ribosomal RNA of C. piliforme was amplified. The characteristics of these bacilli are consistent with those of of C. piliforme. The PCR technique using paraffin-embedded sections should be useful for confirming C. piliforme infection in spontaneous cases.

Animals↗