Biomedical subjects

T Sakamoto

Publications and source records attributed to T Sakamoto.

At least 19 recordsLinked to original sources

PubMed1998

Induction of plasminogen activator inhibitor type 1 and type 1 collagen expression in rat cardiac microvascular endothelial cells by interleukin-1 and its dependence on oxygen-centered free radicals.

BACKGROUND: Ischemia with or without reperfusion induces the release of diverse products from monocytes, including cytokines such as interleukin-1 (IL-1). To determine whether these phenomena modulate fibrinolysis and potentially exacerbate impairment of the macrocirculation, microcirculation, or both, we characterized the effects of IL-1 on the expression of fibrinolytic system and matrix proteins in rat cardiac microvascular endothelial cells (CMECs). METHODS AND RESULTS: Confluent CMECs were exposed to IL-1 in serum-free medium for 24 hours, and cell-conditioned medium was assayed for plasminogen activator inhibitor type 1 (PAI-1), the primary physiological inhibitor of plasminogen activators, and for type 1 collagen with Western blotting. IL-1 (2 ng/mL) specifically increased the accumulation of PAI-1 (4.4 +/- 0.6-fold; mean +/- SD; n = 9) without affecting tissue plasminogen activator (t-PA) or urokinase plasminogen activator (u-PA) levels, which remained unchanged. IL-1 increased the accumulation of collagen in conditioned media by 3.5 +/- 0.7-fold (n = 6). Conversely, the accumulation of both PAI-1 and collagen induced by IL-1 was inhibited with an IL-1 receptor antagonist (200 ng/mL; n = 6) and with cycloheximide (10 micrograms/mL; n = 6), implying that protein synthesis was a requirement for the effect. To determine whether the IL-1 effect was mediated by induction of oxygen-centered free radical production, known to be induced by IL-1, we exposed the cells to the hydroxyl radical scavenger tetramethylthiourea (10 mmol/L) and observed abolition of the IL-1-induced increase in the expression of PAI-1 and collagen (n = 6). Conversely, superoxides (generated with 10 mU/mL xanthine oxidase plus 0.6 mmol/L hypoxanthine, and 100 mumol/L hydrogen peroxide) induced the accumulation of PAI-1 and collagen (n = 6). IL-1 (1 microgram/kg body wt) and lipopolysaccharide (50 micrograms/kg body wt) administered in vivo increased PAI-1 protein in rat hearts as detected with Western blotting and PAI-1 immunostaining of rat heart microvessels, indicating the effects delineated in vitro were paralleled by effects in vivo. CONCLUSIONS: These results indicate that IL-1-induced oxygen-centered free radicals stimulate elaboration of PAI-1 and collagen by CMECs. Accordingly, microvascularly mediated inhibition of fibrinolysis may predispose to the persistence of microvascular thrombi, thereby contributing to impaired microcirculatory function, the no-reflow phenomenon, and cardiac dysfunction after ischemia and reperfusion.

Animals↗

PubMed1998

Retinal functional change caused by adenoviral vector-mediated transfection of LacZ gene.

We examined the effect of insertion of an exogenous gene on retinal function to assess the rationale of adenoviral vector-mediated gene transfer for future gene therapy. An adenoviral vector expressing bacterial LacZ (AdCALacZ) was injected into the eyes of adult rats either intravitreally (group A) or subretinally (group B), and the gene expression and retinal function were thus examined at different time points after gene transfer for 3 weeks. X-Gal histostaining showed that neural retinal cells were transfected in group A and that retinal pigment epithelial cells were transfected in group B. The gene transfer was more efficient in group B (54.4% of the fixed retinal area was stained) than in group A (10.4%). The electroretinogram (ERG) revealed retinal dysfunction in the AdCALacZ-transfected rats even at the stage in which the histological damage was not apparent by electron microscopy and immunohistochemical studies for cytokeratin, S-100 protein, and glial fibrillary acidic protein. The ERG change was correlated with the intensity of inflammation, and retinal function recovered to the original level by 3 weeks, along with a diminution of inflammation. Functional changes were more evident in eyes treated with AdCALacZ than in those infected with adenoviral vector with no exogenous gene; however, no histological difference was observed between these groups, indicating that the insertion of exogenous gene itself affects retinal function. The results showed that different kinds of retinal cells could be gene-transferred by an adenoviral vector, depending on the application method. The retinal dysfunction caused by each adenoviral transfection method was caused by inflammation and the insertion of exogenous gene, and this retinal dysfunction was recoverable. In future gene therapy, special attention should be given to the method of exogenous gene insertion in the retina.

Adenoviridae↗

PubMed1998

A new pseudo-peptide analogue of the Arg-Gly-Asp (RGD) sequence inhibits liver metastasis of colon 26-L5 carcinoma cells.

We have investigated the effect of the pseudo-peptide analogue (FC-336) of the Arg-Gly-Asp (RGD) sequence in a liver metastasis model by the inoculation of a highly liver-metastatic cell line of colon 26 carcinoma (colon 26-L5) into the portal vein of BALB/c mice. The intraportal injection of colon 26-L5 cells with FC-336 resulted in a marked suppression of liver metastatic colonies in a dose-dependent manner and it reduced the liver weights to a normal level. However, the co-injection of tumor cells with a high dose of RGDS tetrapeptide led to a slight inhibition of liver metastasis. The multiple i.v. administration of FC-336 after tumor inoculation as well as the injection of FC-336 with tumor cells caused significant inhibition of experimental metastasis in the liver. The multiple i.v. administration of the RGDS peptide did not show any inhibitory activity. FC-336 significantly enhanced the survival rate of mice compared with untreated controls when injected intraportally with tumor cells or when intravenously administered after tumor inoculation. Zymography analysis showed that FC-336 inhibited the degradation of gelatin substrate by matrix metalloproteinases (MMPs) produced by colon 26-L5 cells, while RGDS peptide did not affect the enzymatic degradation. These findings clearly indicate that the pseudo-peptides of the RGD sequence (FC-336) have a potent inhibitory activity on liver metastasis of colon 26-L5 carcinoma cells.

Animals↗

PubMed1998

Efficacy and safety of early coronary stenting for unstable angina.

To determine the efficacy and safety of early coronary stenting for unstable angina, we studied 91 consecutive patients with unstable angina. Thirty-one patients underwent stenting 72 h or more after admission, and another 60 patients underwent stenting within 72 h of admission. The clinical and angiographic follow-up had been done for 6 mo. There were no differences between the baseline clinical and angiographic characteristics of both groups. The maximum balloon pressure was higher (14.1 +/- 1.2 vs. 12.6 +/- 0.9, P < 0.01) and the hospital stay was shorter (9.7 +/- 2.7 vs. 18.7 +/- 5.8 d, P < 0.0001) in the early stenting group. These two groups were similar in the clinical success rate (90.0% vs. 93.5%), without any abrupt closure, subacute thrombosis, death, myocardial infarction, or coronary bypass surgery. These findings indicate that early stenting can be useful in patients with unstable angina.

Aged↗

PubMed1998

Analysis of lobectomy for small peripheral lung cancer supports extended segmentectomy.

We reviewed the records of 53 patients who underwent lobectomy for peripheral non-small cell lung cancer under 2 cm in diameter and established a rationale for segmentectomy with intraoperative lymph nodes dissection (extended segmentectomy). Five patients (9.4%) had intrapulmonary metastases. Nodal status was N0 in 34 patients (64.2%), N1 in 7 (13.2%), and N2 in 12 (22.6%). Based on examination of intraoperative frozen sections, 31 patients lacking lymph node metastases and visceral pleural involvement could have been candidates for extended segmentectomy. Twenty-seven had stage I disease on postoperative examination of paraffin-embedded sections. Of the remaining 4 patients, 1 had involvement of intrapulmonary lymph nodes in the segment where the primary lesion originated. Another patient had involvement only at the first mediastinal lymph node level, representing a "skipping metastasis". The remaining 2 patients had no lymph node involvement, but had intrapulmonary metastases in the same segments as the primary lesion. We conclude that an extended segmentectomy may be as effective as lobectomy for treatment of peripheral non-small cell lung cancer under 2 cm in diameter without evident lymph node involvement.

Adult↗

PubMed1998

[Open heart surgery without blood transfusion for cyanotic congenital cardiac defects].

Between November 1994 and January 1997, 42 cases of cyanotic congenital cardiac defects underwent definitive surgery at Matsudo Municipal Hospital. We evaluated 30 cases, each weighing from 7 to 20 kg. The procedures were performed at the age of 9 months to 6 years (mean age-2.4 years). The body weights were 7.7 to 20 kg (mean weight-11.4 kg). The preoperative diagnoses were Tetralogy of Fallot (TOF) in 19 cases, Fontan candidates in 6 and the others in 5. We classified them into 3 groups; Group A--15 cases were completed with non-blood transfusion, Group B--8 cases used only plasma protein fraction and Group C--7 cases used blood transfusion. Cardiopulmonary bypass (CPB) system is a semi-closed circuit and priming volume is 400 to 600 ml. There is no difference among the 3 groups in operative age, body weight, operation time, CPB time, aortic cross clamp time, bleeding and postoperative state. The same results were obtained in minimum base excess and urine output during CPB and the changes of hematocrit and total protein. In Groups A and B, CPB blood was returned to the patient as soon as possible after CPB was weaned, but in Group C, blood transfusion was performed without the return of CPB blood. In all groups, hemodynamics were stable. Retrospectively, it is thought that blood transfusion was not necessary in Group C and the use of the plasma protein fraction was not needed in Group B. In conclusion, the open heart surgery can be performed safely without blood transfusion for cyanotic congenital cardiac defects.

Blood Transfusion↗

PubMed1998

Elimination of neutrophils by apoptosis during the resolution of acute pulmonary inflammation in rats.

We evaluated the apoptosis of neutrophils during the resolution of acute pulmonary inflammation induced by exposure to ozone. The inflammatory response was assessed in rat lungs 0, 1, 3, and 7 days after 4-h exposure to air or 2 ppm ozone. Analysis of bronchoalveolar lavage fluid demonstrated significant increases in albumin concentrations on days 0 and 1 and in the number of lavageable neutrophils on days 0, 1, and 3, indicating the presence of acute pulmonary inflammation. These parameters returned to control values on day 7, which suggests that the acute pulmonary inflammation induced by ozone was reversible. On days 1 and 3, but not on day 0, the neutrophils showed morphologic evidence of apoptosis. Based on morphologic analysis, the proportion of apoptotic neutrophils was 23.3 +/- 2.2% on day 1 and 55.7 +/- 3.2% on day 3. Terminal deoxynucleotidyl transferase-mediated dUTP end labeling (TUNEL), in contrast, revealed that the proportion of apoptotic cells was 59.7 +/- 9.1% on day 1 and 68.0 +/- 4.3% on day 3. On day 3, light microscopy and electron microscopy demonstrated engulfment of the neutrophils by macrophages. These findings indicate that the apoptosis of neutrophils followed by their engulfment by macrophages contributes to the clearance of neutrophils from the sites of inflammation. Moreover, TUNEL detected apoptotic neutrophils with greater sensitivity compared with morphologic assessment.

Acute Disease↗

PubMed1998

Growth at low temperature causes nitrogen limitation in the cyanobacterium Synechococcus sp. PCC 7002.

The coloration of cells of the cyanobacterium Synechococcus sp. PCC 7002 changed from normal blue-green to yellow-green when cells were grown at 15 degrees C in a medium containing nitrate as the sole nitrogen source. This change of coloration was similar to a general response to nutrient deprivation (chlorosis). For the chlorotic cells at 15 degrees C, the total amounts of phycobiliproteins and chlorophyll a decreased, high levels of glycogen accumulated, and growth was arithmetic rather than exponential. These changes in composition and growth occurred in cells grown at low (50 microE m-2 s-1) as well as high (250 microE m-2 s-1) light intensity. After a temperature shift-up to 38 degrees C, chlorotic cells rapidly regained their normal blue-green coloration and normal exponential growth rate within 7 h. When cells were grown at 15 degrees C in a medium containing urea as the reduced nitrogen source, cells grew exponentially and the symptoms of chlorosis were not observed. The decrease in photosynthetic oxygen evolution activity at low temperature was much smaller than the decrease in growth rate for cells grown on nitrate as the nitrogen source. These studies demonstrate that low-temperature-induced chlorosis of Synechococcus sp. PCC 7002 is caused by nitrogen limitation and is not the result of limited photosynthetic activity or photodamage to the photosynthetic apparatus, and that nitrogen assimilation is an important aspect of the low-temperature physiology of cyanobacteria.

Bacterial Proteins↗

PubMed1998

Alteration of low-temperature susceptibility of the cyanobacterium Synechococcus sp. PCC 7002 by genetic manipulation of membrane lipid unsaturation.

Cyanobacteria acclimate to low temperature by desaturating their membrane lipids. Mutant strains of Synechococcus sp. PCC 7002 containing insertionally inactivated desA (Delta12 acyl-lipid desaturase) and desB (omega3 acyl-lipid desaturase) genes were produced, and their low-temperature susceptibility was characterized. The desA mutant synthesized no linoleic acid or alpha-linolenic acid, and the desB mutant did not produce alpha-linolenic acid. The desA mutant grew more slowly than the wild-type at 22 degrees C and could not grow at 15 degrees C. The desB mutant could not continuously grow at 15 degrees C, although no observable phenotype appeared at higher temperatures. It has been shown that expression of the desA gene occurs at 38 degrees C and is up-regulated at 22 degrees C, and that the desB gene is only expressed at 22 degrees C. These results indicate that the expression of the desA and desB genes occurs at higher temperatures than those at which a significant decline in physiological activities is caused by the absence of their products. The temperature dependency of photosynthesis was not affected by these mutations. Since chlorosis and inability to grow at 15 degrees C with nitrate was suppressed by the substitution of urea as a nitrogen source, it is very likely that the chilling susceptibility of the desaturase mutants is attributable to nutrient limitation.

Adaptation, Physiological↗

PubMed1998

Synergistic effect of electric pulses and bleomycin on cultured rabbit subconjunctival fibroblasts.

BACKGROUND: The combined effect of electric pulses (EP) and antiproliferative agents on the proliferation of rabbit Tenon's capsule fibroblasts was investigated. METHODS: Rabbit Tenon's capsule fibroblasts were cultured. Some of these cells were exposed to various intensities of EP alone (500-2500 V/cm). Other cells were then exposed for 30 min to an antiproliferative agent: bleomycin (BLM; 0.0005-50 mumol/l), mitomycin C (MMC; 0.0005-50 mumol/l), 5-fluorouracil (5-FU; 0.05-5000 mumol/l), or streptomycin (SM; 0.0005-50 mumol/l) with or without EP (2000 V/cm, 99 mus, eight pulses). Cell proliferation was assessed by cell counting on day 3 and by a 3H-thymidine uptake assay. DNA fragmentation was assessed by flow-cytometric analysis and agarose gel electrophoresis. RESULTS: A significant reduction in the cell number was observed only at 2500 V/cm (P < 0.05). BLM, MMC and 5-FU treatment inhibited cell proliferation in a dose-dependent manner either with or without EP (ID50: BLM alone, 0.029 mumol/l; BLM and EP, 0.00022 mumol/l; MMC alone, 41.6 mumol/l; MMC and EP, 27.5 mumol/l; 5-FU alone, 1045 mumol/l; 5-FU and EP, 690.2 mumol/l; P < 0.05). EP treatment induced an inhibitory effect of BLM on cell proliferation which was 100 times more prominent than BLM alone (0.0005 mumol/l of BLM alone 103.4 +/- 4.4%, 0.0005 mumol/l of BLM and EP 26.0 +/- 4.4%; P = 0.021). BLM treatment with EP also augmented the apoptotic-like DNA fragmentation in both a flow-cytometric DNA histogram and agarose gel-electrophoresis. CONCLUSION: EP treatment enhanced the inhibitory effect of BLM on the cell proliferation of Tenon's capsule fibroblasts of rabbits. The combination of electric pulses and antiproliferative drug treatments may therefore reduce the necessary dose of antiproliferative agents in filtering surgery.

Animals↗

PubMed1998

Ability of retroviral transduction to modify the angiogenic characteristics of RPE cells.

BACKGROUND: Retinal pigment epithelial (RPE) cells play an important role in the modulation of ocular angiogenesis. Transduction of RPE cells with retroviral vectors bearing modulating genes can result in long-term transgene expression and may alter the angiogenic characteristics of RPE cells. This study was designed to determine whether changes in angiogenic characteristics of RPE cells result from transduction with retroviral vectors bearing modulating genes, using in vitro angiogenic assays, including analysis of endothelial proliferation and wound healing. METHODS: Human RPE cells were transduced with retroviral vectors bearing either a urokinase-type plasminogen activator (u-PA) or a tissue-type plasminogen activator (t-PA) cDNA. Ten weeks after gene transfer, RPE cells transduced with the u-PA (u-PA-RPE cells) or the t-PA cDNA (t-PA-RPE cells), or untransduced (control) RPE cells, were cocultured with human umbilical vein endothelial cells (HUVECs) by contacting and non-contacting coculture methods. The effects of these cells on proliferation and in vitro "wound healing" of HUVECs were evaluated. RESULTS: Over 18 weeks, u-PA-RPE cells released large amounts of biologically active u-PA (total amount, 50.2 +/- 9.7 ng/10(6) cells/24 h), while t-PA-RPE cells released large amounts of functional t-PA (15.4 +/- 3.2 ng/10(6) cells/24 h). Control RPE cells did not release any detectable t-PA or u-PA. In the proliferation assay, u-PA-RPE cells stimulated HUVEC proliferation in contacting cell cultures, but not in non-contacting cell cultures. In contrast, t-PA-RPE cells, normal RPE cells or exogenous u-PA had no effect on HUVEC proliferation. In the wound healing assay, u-PA-RPE cells in contacting coculture and exogenous u-PA stimulated wound healing of HUVECs, while non-contacting u-PA-RPE cells, t-PA-RPE cells and normal RPE cells had no effect on HUVEC wound healing. RPE cells transduced with u-PA secreted large amounts of u-PA for as long as 18 weeks, and these cells stimulate HUVEC proliferation and in vitro wound healing. As a result, the angiogenic characteristics of RPE cells can undergo long-term changes. CONCLUSIONS: These results suggest that genetically modified RPE cells can be used to modulate ocular angiogenesis and may have potential for gene therapy of ocular diseases.

Cell Division↗

PubMed1998

A case of resection under the IVC-atrial venovenous bypass of a hepatoblastoma after intraarterial chemotherapy.

An 11-month-old infant with a huge hepatoblastoma occupying almost the entire liver was admitted to the hospital. Serum alpha fetoprotein (AFP) level was elevated to 685,120 ng/mL. Combination chemotherapy with continuous arterial infusion of tetrahydropyranyl Adriamycin (THP-Adriamycin) and cisplatin based on the 91B1 protocol of the Japanese Study Group For Pediatric Liver Tumor (JPLT) was administered as the adjuvant chemotherapy. The tumor responded to three courses of chemotherapy and shrank in size, although venocavography showed that the inferior vena cava (IVC) was completely occluded below the entry of the hepatic veins. Right hepatic trisegmentectomy was performed with an IVC-atrial venovenous bypass that prevented massive bleeding. In this case, it was recognized that the IVC-atrial venovenous bypass was advantageous in an infant. The procedure is very simple and the blood flow obtained by the bypass was sufficient. Two weeks postoperatively, three courses of chemotherapy were initiated after the protocol. The patient remains well without signs of recurrence 39 months postoperatively, and the AFP value has remained within 10 ng/mL.

Antibiotics, Antineoplastic↗

PubMed1998

L-arginine, a nitric oxide precursor, attenuates ischemia-reperfusion injury by inhibiting inositol-1,4,5-triphosphate.

OBJECTIVE: We evaluated the effect of pretreatment with nitric oxide precursor before ischemia on recovery with reperfusion in rat hearts. METHODS: Isolated rat hearts were perfused with Krebs-Henseleit buffer without (C group) or with 3 mmol/L L-arginine (A group) before 30 minutes of ischemia. The left ventricular function, including heart rate, developed pressure, maximal dp/dt, and coronary flow, were measured before pretreatment and after 10 and 30 minutes of reperfusion. Cyclic guanosine monophosphate (by radioimmunoassay), calcium (by absorption spectrophotometry), and inositol 1,4,5-triphosphate synthesized from tritiated myo-inositol (by ion-exchange chromatography preceding counting) were measured at the same times and immediately after ischemia. RESULTS: Recovery of ventricular function was significantly greater in the A group than in the C group. Pretreatment increased postischemic cyclic guanosine monophosphate content compared with the preischemic level (from 1.06 +/- 0.12 to 1.94 +/- 0.09 pmol/mg protein, p < 0.05). No change in cyclic guanosine monophosphate was evident in the C group. In the C group, inositol triphosphate content increased after 10 minutes of reperfusion beyond the preischemic level (from 0.53 +/- 0.023 to 1.15 +/- 0.045 cpm x 10(-3)/gm, p < 0.05) as did calcium at 30 minutes (from 4.12 +/- 0.164 to 6.86 +/- 0.544 mmol/gm dry weight). In the A group, both of these increases were significantly attenuated. CONCLUSION: These data suggest that L-arginine pretreatment may reduce calcium overload by increasing cyclic guanosine monophosphate production, which in turn downregulates inositol triphosphate synthesis during reperfusion.

Animals↗

PubMed1998

Incorporation of phencyclidine and its hydroxylated metabolites into hair.

The incorporation of phencyclidine(PCP) and its three major hydroxylated metabolites, 1-(1-phenylcyclohexyl)-4-hydroxypiperidine(PCHP), trans-4-phenyl-4-piperidinocyclohexanol(t-PPC) and trans-1-phenyl-1-(4'-hydroxypiperidino)-4-cyclohexanol(t-PCPdiol) into rat hair was studied. Three Dark Agouti male rats were intraperitoneally administered with PCP x HCl at a dose of 0.5 or 1.0 mg/kg once a day for 10 successive days. The plasma samples were collected from 5 min to 360 min after injection of each drug. The hair samples were collected 28 days after the first administration. The hair samples were extracted with methanol-5N hydrochloric acid(20:1) for 1 h under sonication. The plasma and hair extracts were extracted or purified with Bond Elut Certify and the extracts were silylated for the determination of PCP and its metabolites by GC/MS. The plasma AUCs were as follows; PCP(2.03 microg x min/ml) > t-PCPdiol(0.60 microg x min/ml) > PCHP(0.11 microg x min/ml) > t-PPC (0.065 microg x min/ml), while the hair concentrations were as follows; PCP(7.51 ng/mg) > PCHP (1.22 ng/mg) > t-PPC(0.10 ng/mg) > t-PCPdiol (0.05 ng/mg). In view of their AUCs, the hair concentration of t-PCPdiol was quite low, whereas that of PCP was so high. PCHP, t-PPC or t-PCPdiol was separately administered as the parent drug to the rats, and then the plasma and hair samples were analyzed in the same manner as PCP experiments. The incorporation rates ([hair concentration]/[AUC]) of PCP and its hydroxylated metabolites were as follows; PCP(2.29) > PCHP(0.79) > t-PPC(0.36) > t-PCPdiol(0.32). These data suggest that the decrease in lipophilicity caused by the hydroxylation of PCP suppresses the incorporation of the metabolites from blood into hair and the hydroxylation on cyclohexane ring(t-PPC) induces the decrease of the drug incorporation into hair more than that on piperidine ring(PCHP).

Animals↗

PubMed1998

Modulation of eosinophil chemotactic activities to leukotriene B4 by n-3 polyunsaturated fatty acids.

Eosinophil accumulation induced by leukotriene B4 appears to be involved in the pathogenesis of allergic diseases. We evaluated the effects of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) on chemotaxis to leukotriene B4 in guinea pig peritoneal eosinophils. Guinea pigs that were sensitized to polymyxin B were administered an intraperitoneal injection of polymyxin B (1 mg/animal) alone or combined with DHA (15 or 50 mg/kg, i.p.), EPA (50 or 100 mg/kg, i.p.), or with linoleic acid (LA) (100 mg/kg, i.p.). Forty hours later, eosinophils were obtained from the intraperitoneal lavage fluid and purified. The chemotactic and chemokinetic responses of eosinophils to leukotriene B4 were measured using a 96-well microchemotaxis chamber. DHA significantly decreased the chemotactic and chemokinetic responses of eosinophils in a dose-dependent fashion. A higher dose of EPA also significantly inhibited both of those responses, whereas LA had no effect. Our results suggested a possible mechanism for the improvement of allergic diseases by dietary supplementation with n-3 PUFA.

Animals↗

PubMed1998

Immunological determination of faecal haemoglobin concentrations in dogs.

Faecal haemoglobin (Hb) concentrations in apparently healthy experimental Beagle dogs and in dogs of various breeds kept in private households or at breeders were measured by reversed passive latex agglutination (RPLA) and enzyme-linked immunosorbent assay (ELISA) in an effort to define the physiological concentrations of faecal Hb in the dog. In 88% (53) of 60 experimental Beagle dogs (30 males and 30 females), the RPLA titres were 1:2 and 1:8 and the faecal Hb concentrations ranged from 40.0 to 431.5 (mean 184.1 +/- 92.6) micrograms/g faeces by ELISA. No significant difference was found in Hb levels or RPLA titres between males and females. Seven dogs (12%) had significantly greater RPLA titres and Hb concentrations by ELISA than the remaining dogs. In 84% (45) of the 53 dogs kept in private households or at breeders, the RPLA titres were < 1:1 to 1:8 and the faecal Hb concentrations ranged from 7.1 to 456.7 (mean 137.5 +/- 128.7) micrograms/g faeces in ELISA. Eight of these dogs (15.1% of 53 dogs) had significantly greater RPLA titres and Hb concentrations by ELISA than the remaining dogs. There were no significant differences between the Beagles and dogs kept in private households or at breeders. In conclusion, in 98 (86.7% of 113) dogs the physiological concentrations of RPLA titres were < 1:1 to 1:8 and the faecal Hb concentrations were 143.5-185.1 micrograms/g (95% confidence level). Approximately 13.3% of apparently healthy dogs had higher faecal Hb concentrations, suggesting the presence of subclinical haemorrhages. Four dogs suffering from colorectal cancer also had high faecal Hb concentrations.

Animals↗

PubMed1998

Molecular and biological characterization of rabbit mannan-binding protein.

Mannan-binding protein (MBP) is a member of the collectin family of protein. There are two types of MBP, MBP-A and MBP-C, which were found in rodent (rats and mice), rhesus monkey, and cynomolgus monkey, while chimpanzee and human have only one MBP. It was considered that the loss of one MBP gene occurred during hominoid evolution. In this article two rabbit MBP, a liver and serum MBP, were characterized biologically and genetically. Analyses by SDS-PAGE under reduced condition and their amino acid sequences of both MBPs showed that they have a same molecular weight of 32 kDa and their amino acid sequences were identical. A serum MBP has a higher ability to activate complement than does a liver MBP; however, a liver MBP inhibits hemagglutination by influenza virus as strongly as a serum MBP does. cDNA clones encoding the rabbit MBP were isolated from a rabbit cDNA liver library using whole cDNA of mouse MBP-C as a probe. The cDNA carried an insert of 744 bp coding for a protein of 247 acid residues with a signal peptide of 22 residues. The deduced amino acid sequence of the cDNA was identical to that of amino acid sequences of the 32 kDa proteins determined here. Northern blot analysis showed that mRNA transcripts of about 0. 9 and 3.0 kb were expressed only in the liver. The analysis of the phylogenetic tree of rabbit and bovine MBPs and other collectins indicates that the loss of MBP gene occurred not only during hominoid evolution but also at some points after the separation of birds and mammals.

Amino Acid Sequence↗

PubMed1998

Mild hypothermia can attenuate nitroglycerin-induced vasodilation of pial arterioles in the cat.

UNLABELLED: The purpose of the present study was to investigate the effect of mild hypothermia on nitroglycerin-induced vasodilation of cerebral vessels. The cranial window technique, combined with microscopic video recording, was used in an experiment involving 26 cats anesthetized with isoflurane. Animals were randomly assigned to either a normothermic or a mildly hypothermic group (33 degrees C). We administered three different concentrations of nitroglycerin (10[-6], 10[-5], 10[-4] M) under the window and measured the diameter of small (< 100 microm) and large (100-200 microm) pial arterioles. In the normothermic group (n = 13), nitroglycerin produced a significant dilation of both small and large arterioles in a dose-dependent manner. In the hypothermic group (n = 13), a significant dilation of arterioles was observed only after topical application of nitroglycerin at a concentration of 10(-4) M. The percent increase in diameter of small and large arterioles was less in the hypothermic group than the normothermic group. Our in vivo study demonstrates that topically applied nitroglycerin produces a dose-dependent dilation of pial arterioles in normothermic cats anesthetized with isoflurane, but the reduction of temperature to 33 degrees C significantly attenuates nitroglycerin-induced vasodilation of pial arterioles. IMPLICATIONS: Although nitroglycerin may be used in hypothermic patients, the effect of mild hypothermia on nitroglycerin-induced vasodilation of cerebral vessels is unknown. In this study, we investigated the effects of nitroglycerin on pial arteriolar diameter in normothermic and hyperthermic cats. Hypothermia was found to attenuate nitroglycerin-induced vasodilation.

Animals↗