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Biomedical subjects

W Zhang

Publications and source records attributed to W Zhang.

At least 901 records · Page 50Linked to original sources
PubMed1997

Glutamine protects function and improves preservation of small bowel segments.

BACKGROUND: Improved organ preservation is essential for the success of small bowel transplantation. Small bowel is usually preserved in UW (University of Wisconsin) solution which does not contain glutamine (Gln), the principal fuel for the enterocyte. We hypothesized that Gln-supplemented UW would improve mucosal function and structure of cold preserved small intestine. MATERIALS AND METHODS: Jejunum (40 cm) was harvested from Lewis rats and preserved for 18 hr at 4 degrees C in saline; UW solution only; UW with 1, 2, or 4% Gln; and UW containing 1, 2, or 4% isonitrogenous balanced nonessential amino acids (NEAA). 14C glucose transport, mucosal protein, mucosal maltase and alkaline phosphatase, jejunal villous height, and histologic damage were measured. RESULTS: UW with 2% Gln significantly increased glucose transport and mucosal protein when compared to the 2% NEAA and UW-only groups. Two percent Gln significantly decreased histologic damage of jejunum following cold preservation. Increasing Gln to 4% did not significantly increase its efficacy when compared to the UW with 2% Gln group. There were no significant differences in the activities of mucosal maltase and alkaline phosphatase among the various treatment groups. CONCLUSIONS: The addition of Gln, optimally provided at a concentration of 2%, to UW solution may protect the preserved small bowel segments from cold ischemic injury and improve mucosal function.

Alkaline Phosphatase↗
PubMed1997

Bamboozled again! Inadvertent isolation of fungal rDNA sequences from bamboos (Poaceae: Bambusoideae).

Polymerase chain reaction (PCR) amplification of the nuclear internal transcribed spacer (ITS) and 5.8S regions of rDNA from woody bamboos (Bambuseae) led to the recovery of fungal instead of bamboo sequences under a variety of PCR conditions and irrespective of whether the plant DNA was extracted from fresh leaves or silica gel-dried material. Phylogenetic analyses based on the 5.8S sequences indicated that the fungi were most likely basidiomycetes and that none was an ascomycete. A diverse assemblage of nonascomycetous fungi was isolated from different bamboos, and various fungi coexisted in the same host plant. There was no evidence that closely related fungi consistently associate with closely related host bamboos. Phylogenetic analysis based on 5.8S sequences showed that some fungi were in lineages near Volvariella, Lentinula, Peniophora, and Rhizoctonia, but the insufficiency of basidiomycete and zygomycete ITS sequences in sequence data bases precluded more precise fungal identifications. Bamboo ITS regions were amplified only when fresh leaves were surface sterilized before DNA extraction, suggesting that the fungal associates are epiphyllous rather than endophytic. This study highlights the possibility of inadvertent PCR amplification of contaminating DNAs in molecular phylogenetic studies, particularly when using "universal" amplification primers.

Base Sequence↗
PubMed1997

Osteosarcoma of the meninges in association with glioblastoma.

Primary intracranial osteosarcoma not originating in the skull is a distinctly rare tumour, as is post-irradiation sarcoma of short latency. The authors report the case of a 56 year old caucasian male who underwent resection of a glioblastoma of the left temporal region and was subsequently administered partial field external beam radiation therapy (XRT) to a total dose of 5940 cGy. Seven months following the completion of XRT, an enhancing region adjacent to the surgical site was noted on followup magnetic resonance images (MRI), one which increased in size on serial studies. Initial biopsy of the dural lesion adjacent to the temporal resection site revealed a sarcoma with a suggestion of osseous differentiation. Subsequent reoperation with resection of the lesion showed it to be a primary meningeal tumour, and histological evaluation of the lesion demonstrated an osteosarcoma. Immunohistochemical staining for p53 protein performed on both the original glioblastoma and the subsequently resected osteosarcoma showed widespread nuclear positivity. The clinical, radiographic and pathologic features of this unusual case are discussed. Meningeal osteosarcoma should be included among the rare secondary sarcomas of the meninges which may be associated with malignant glioma.

Bone Neoplasms↗
PubMed1997

The factors related to fungal peritonitis in patients on peritoneal dialysis.

Fungal peritonitis (FP) is a serious infectious complication of peritoneal dialysis (PD). This retrospective study was conducted in 11 cases of FP among 64 cases of patients with bacterial peritonitis (BP). Our results showed that age and sex underlying disease did not correlate significantly with the development of FP (P > 0.05), while long-term, repeated administration of antibiotics did (P < 0.01). It is suggested that the patients recently suffering from BP and being resistant to antibiotics were at great risk of suffering from FP. The key to prevent FP was to avoid BP, to use sensitive antibiotics with appropriate courses and to give nutritive treatment.

Aged↗
PubMed1997

Effects of the medium conditioned by endothelial cells under hypoxic condition on the phenotype of porcine pulmonary arterial smooth muscle cells.

The effects of the medium conditioned by endothelial cells under hypoxic condition on the phenotype modulation of pulmonary artery smooth muscle cells (PASMCs) were investigated by using cell culture and morphometrical analysis. The results showed that the number of diploid cells and alpha-sm-actin of PASMCs in the hypoxic endothelial cell conditioned medium group (HECCM) was lower and the myofibrilles were even less than that in normal endothelial cell conditioned medium group (NECCM). On the contrary, the volume density of rough endoplasmic reticulum (RER) and mitochondria of PASMCs in the HECCM group was higher than that in the NECCM group, i.e. altering from a contractile type to a synthetic type. However, under direct hypoxic condition for 24 h, the phenotype of cultured PASMCs remained unchanged, i.e. retained contractile type. It suggests that the HECCM can induce phenotype modulation of PASMCs, may be mediated by the pulmonary artery endothelial cells (PAECs) which can secrete some cytokins affecting the PASMCs.

Animals↗
PubMed1997

Meniscal injury in children: long-term results after meniscectomy.

Twenty-four children who underwent open total meniscectomy were reviewed and followed-up for an average of 16.1 years (range 6-33 years). There were 7 boys and 17 girls aged between 7 and 16 years (average 12.5 years). Excellent and good results were noted in 62.5% of the patients. Eighty-seven of the children showed radiographic degeneration of the knee joint. This study in a Chinese population indicates that meniscectomy is not a benign procedure in children, and total meniscectomy should be avoided as far as possible.

Adolescent↗
PubMed1997

Fluoride treatment increased serum IGF-1, bone turnover, and bone mass, but not bone strength, in rabbits.

We hypothesized that fluoride partly acts by changing the levels of circulating calcium-regulating hormones and skeletal growth factors. The effects of oral fluoride on 24 female, Dutch-Belted, young adult rabbits were studied. The rabbits were divided into two study groups, one control and the other receiving about 16 mg fluoride/rabbit/day in their drinking water. After 6 months of fluoride dosing, all rabbits were euthanized and bone and blood samples were taken for analyses. Fluoride treatment increased serum and bone fluoride levels by over an order of magnitude (P < 0.001), but did not affect body weight or the following serum biochemical variables: urea, creatinine, phosphorus, total protein, albumin, bilirubin, SGOT, or total alkaline phosphatase. No skeletal fluorosis or osteomalacia was observed histologically, nor did fluoride affect serum PTH or Vitamin D metabolites (P > 0.4). BAP was increased 37% (P < 0.05) by fluoride; serum TRAP was increased 42% (P < 0.05); serum IGF-1 was increased 40% (P < 0.05). Fluoride increased the vertebral BV/TV by 35% (P < 0.05) and tibial ash weight by 10% (P < 0.05). However, the increases in bone mass and bone formation were not reflected in improved bone strength. Fluoride decreased bone strength by about 19% in the L5 vertebra (P < 0.01) and 25% in the femoral neck (P < 0. 05). X-ray diffraction showed altered mineral crystal thickness in fluoride-treated bones (P < 0.001), and there was a negative association between crystal width and fracture stress of the femur (P < 0.02). In conclusion, fluoride's effects on bone mass and bone turnover were not mediated by PTH. IGF-1 was increased by fluoride and was associated with increased bone turnover, but was not correlated with bone formation markers. High-dose fluoride treatment did not improve, but decreased, bone strength in rabbits, even in the absence of impaired mineralization.

Acid Phosphatase↗
PubMed1997

Involvement of MHC class I molecule and ICAM-1 in the enhancement of adhesion and cytotoxic susceptibility to immune effector cells of tumor cells transfected with the interleukin (IL)-2, IL-4 or IL-6 gene.

To investigate the molecular and cellular mechanisms involved in the reduced tumorigenicity and increased immunogenicity of interleukin-2 (IL-2)-, IL-4- or IL-6-gene-transfected B16 melanoma vaccine, we have analyzed the functional and phenotypic properties of these genetically engineered melanoma cells in the present study. The cytokine-gene-transfected B16 melanoma cells showed stronger adhesion to the lymphokine-activated killer (LAK) cells or cytotoxic T lymphocytes (CTL), and higher sensitivity to cytotoxicity of LAK cells or CTL. Using fluorescence-activated cell sorting analysis, we found that both MHC class I and ICAM-1 expression were increased after IL-2, IL-4 or IL-6 gene transfection. The increased level of MHC class I and ICAM-1 expression seems to be responsible for the high sensitivity of these gene-transfected B16 cells to LAK or CTL cytotoxicity because anti-(MHC class I) or anti-ICAM-1 mAb could inhibit the adhesion and cytotoxicity increment simultaneously. The CTL induction was partly inhibited by anti-ICAM-1 mAb and was completely blocked by anti-MHC class I mAb. These results suggested that the decreased tumorigenicity of IL-2-, IL- 4-, and IL-6-gene-transfected B16 melanoma cells may be partly due to the increased sensitivity to effector cell cytotoxicity mediated by increased expression of ICAM-1 or MHC class I molecules on the tumor cell surface after cytokine gene transfection.

Animals↗
PubMed1997

Creation of chimeric hearts: a tool for testing the "passenger leukocyte" hypothesis.

BACKGROUND: Bone marrow-derived antigen-presenting cells (APCs) are thought to be a migratory component of organ allografts that activate the rejection response, and recently they have been postulated to play a critical role in tolerance induction. Our goal was to create chimeric hearts (organs with parenchyma and APCs of differing genotype) for use in models of transplantation to test the "passenger leukocyte" theory. METHODS: Murine bone marrow transplantation were performed in two fully major histocompatibility complex (MHC) mismatched strain combinations: C3H-->B10 and CBA-->BALB/c. Recipients were lethally irradiated (10 Gy) and then received 1 x 10(7) bone marrow cells intravenously. Bone marrow transplant survivors had their organ APCs isolated by digestion with collagenase D, followed by density gradient centrifugation. The APC-enriched fraction was stained with fluorescein-labeled monoclonal antibodies specific for either donor (I-Ak) or recipient (I-Ab/d) class II MHC antigens, which are expressed by all APCs but not by parenchymal cells. Donor and recipient class II expression was determined by flow cytometry. RESULTS: Sixty-nine of 100 (69.0%) of C3H-->B10 and 52/107 (48.6%) of CBA-->BALB/c bone marrow transplant recipients survived more than 100 days, whereas all B10 (n = 12) and BALB/c (n = 10) irradiation controls died within 14 days. Mortality appeared to be caused by engraftment failure as most recipients died before day 20. Flow cytometry demonstrated complete APC replacement in hearts (n = 17) and spleens (n = 40), as APC-enriched fractions stained only for donor class II MHC antigens. CONCLUSION: Bone marrow transplantation leads to replacement of heart APCs in two murine models. Chimeric hearts are now being used to test the role of APCs in allograft rejection and in tolerance induction.

Animals↗
PubMed1997

A myoglobin mutant designed to mimic the oxygen-avid Ascaris suum hemoglobin: elucidation of the distal hydrogen bonding network by solution NMR.

The solution 1H NMR structure of the active site and ligand dissociation rate for the cyanomet complex have been determined for a sperm whale myoglobin triple mutant Leu29(B10)-->Tyr, His64(E7)-->Gln, Thr67(E10)-->Arg that mimics the distal residue configuration of the oxygen-avid hemoglobin from Ascaris suum. A double mutant that retains Leu29(B10) was similarly investigated. Two-dimensional NMR analysis of the iron-induced dipolar shifts, together with the conserved proximal side structure for the two mutants, allowed the determination of the orientations of the paramagnetic susceptibility tensor for each complex. The resulting magnetic axes, together with paramagnetic relaxation and steady-state NOEs, led to a quantitative description of the distal residue orientations. The distal Tyr29(B10) in the triple mutant provides a strong hydrogen bond to the bound cyanide comparable to that provided by His64(E7) in wild-type myoglobin. The distal Gln64(E7) in the triple mutant is sufficiently close to the bound cyanide to severe as a hydrogen bond donor, but the angle is not consistent with a strong hydrogen bond. Dipolar contacts between the Arg67(E10) guanidinium group and the Gln64(E7) side chain in both mutants support a hydrogen-bond to the Gln64(E7) carbonyl group. The much lower oxygen affinity of this triple mutant relative to that of Ascaris hemoglobin is concluded to arise from side-chain orientations that do not allow hydrogen bonds between the Gln64(E7) side-chain NHs and both the ligand and Tyr29(B10) hydroxyl oxygen. Cyanide dissociation rates for the reduced cyanide complexes are virtually unaffected by the mutations and are consistent with a model of the rate-determining step as the intrinsically slow Fe-C bond breaking that is largely independent of any hydrogen bonds to the cyanide nitrogen.

Amino Acid Sequence↗
PubMed1997

Liposome-mediated gene transfer to lung isografts.

OBJECTIVES: Our objective were to determine the feasibility, efficacy, and safety of in vivo and ex vivo liposome-mediated gene transfer to lung isografts. METHODS: Fischer rats were divided into three main groups: (1) Nontransplant setting: Liposome-chloramphenicol acetyl transferase cDNA was intravenously injected, and lungs were harvested at different time points: 2, 6, 12, and 24 hours; 2, 5, 8, and 21 days (n = 3). Chloramphenicol acetyl transferase activity was determined in lungs, hearts, livers, and kidneys. The distribution and type of transfected cells were evaluated by in situ hybridization. Lung toxicity was assessed by arterial oxygen tension, histology, and tumor necrosis factor-alpha levels. (2) In vivo graft transfection: Left lungs were transplanted 6 hours, 4 hours, and 15 minutes after intravenous injection and were assessed for chloramphenicol acetyl transferase activity and arterial oxygen tension on postoperative day 2. (3) Ex vivo graft transfection: Grafts were infused ex vivo with either 660 micrograms (n = 3) or 330 micrograms (n = 3) of DNA complexed to liposomes and stored at 10 degrees C for 4 hours. Chloramphenicol acetyl transferase activity was assessed 44 hours after transplantation. RESULTS: Transgene expression was detected in endothelial cells, macrophages, and interstitial cells. Chloramphenicol acetyl transferase activity was present as early as 2 hours, increased significantly between 6 hours and 8 days, and then decreased to minimal levels by 21 days. Chloramphenicol acetyl transferase activity was greatest in donor lungs and hearts and minimal in livers and kidneys. Arterial oxygen tension was normal in treated animals. Inflammation was minimal, and tumor necrosis factor-alpha levels increased only sevenfold in treated animals. CONCLUSION: In vivo and ex vivo liposome-mediated gene transfer to lung isografts allows significant transgene expression with minimal effects on graft function.

Animals↗
PubMed1997

Pharmacologic inhibition of transglutaminase-induced cross-linking of Alzheimer's amyloid beta-peptide.

The brain of Alzheimer's disease (AD) patients contains deposits of amyloid beta-peptide (A beta). Recent studies have shown that A beta is a substrate for tissue transglutaminase (TGase), which induces the formation of cross-linked dimers and polymers, and that tacrine, indomethacin and deferoxamine, which have widely different chemical structures, attenuate the progression of symptoms of AD. This report evaluated the potential of a total of ten different pharmacological agents to inhibit TGase-induced cross-linking of A beta, including known TGase inhibitors (dansylcadaverine, spermine), non-steroidal anti-inflammatory drugs (indomethacin, meclofenamic acid, diflunisal, salicylic acid), monoamine oxidase inhibitors (tranylcypromine, phenelzine), an acetylcholinesterase inhibitor (tacrine), and an iron chelating agent (deferoxamine). All but one (salicylic acid) of these ten agents had an inhibitory effect on TGase-induced A beta cross-linking. These results suggest that inhibition of TGase-induced cross-linking of A beta is a potential pharmacologic target for the treatment of AD. A method is also presented for the determination of percent inhibition of TGase-induced A beta cross-linking based on the separated monomer, dimer and polymer bands on SDS-PAGE gels.

Amyloid beta-Peptides↗
PubMed1997

Pharmacologic characteristics of excitatory gamma-amino-butyric acid (GABA) receptors in a snail neuron.

1. The pharmacologic characteristics of excitatory gamma-aminobutyric acid (GABA) receptors, termed muscimol II type GABA receptors, found in a giant neuron type, v-LCDN (ventral-left cerebral distinct neuron), of an African giant snail (Achatina fulica Férussac), were studied using the mammalian GABA receptor agonists, antagonists and synergists and GABA uptake inhibitor using the voltage clamp technique. 2. GABA and its agonists, ejected by brief pressure, produced an inward current (Iin) of the following order of potency: trans-t-aminocrotonic acid (TACA) > GABA > muscimol > isoguvacine > 5-aminopentanoic acid and cis-4-aminocrotonic acid (CACA). (+/-)-Baclofen and 3-aminopropylphosphonic acid (APPA) were ineffective. The Iin values produced by GABA, TACA, isoguvacine and CACA were stable for at least 60 min, whereas the Iin induced by muscimol was not. 3. According to the dose-response curves of GABA, TACA, isoguvacine and CACA, measured by the varied pressure duration method, the ED50 value of CACA was larger than those of the other compounds, and Emax of TACA was larger than that of GABA, whereas Emax values of isoguvacine and CACA were smaller. 4. The perfusion of beta-alanine, pentobarbital and 5-aminopentanoic acid inhibited the Iin induced by GABA, whereas (-)-bicuculline, pitrazepin, diazepam and 2-hydroxysaclofen had no effect. 5. From the effects of beta-alanine on the dose-response curves of GABA, measured by the varied pressure duration method, beta-alanine competitively inhibited the Iin caused by GABA. According to the effects of pentobarbital on the dose-response curves of GABA, this drug noncompetitively inhibited the Iin using the varied pressure duration method, and partly competitively and partly noncompetitively using the Y-tube method. The effects of 5-aminopentanoic acid on the dose-response curves of GABA indicated that this drug noncompetitively inhibited the Iin using the varied pressure duration method, and partly noncompetitively and partly uncompetitively using the Y-tube method. 6. The pharmacologic features of the Achatina muscimol II type GABA receptors were similar to those of mammalian GABAC (GABAp1) receptors, except for the effects of pentobarbital.

Animals↗
PubMed1997

Ouabain-sensitive K(+)-dependent outward current caused by threo-beta-hydroxy-L-glutamic acid on a snail neuron.

1. An analog of L-glutamic acid, threo-beta-hydroxy-L-glutamic acid (threo-L-BHGA), was applied locally to the giant neuron of an Achatina snail by pneumatic brief pressure ejection and induced an outward current (Iout) on the ventral-left cerebral distinct neurone (v-LCDN). The present study aimed to elucidate the ionic mechanisms of the Iout caused by threo-L-BHGA (ItL-BHGA) of v-LCDN and the effects of ouabain on this current under voltage clamp. 2. The reversal potentials of ItL-BHGA (EtL-BHGA) of v-LCDN in varied K+o were fitted to the Nernst equation as ItL-BHGA = IK (K+ current) and were almost unchanged in Cl-o-free and Na+o-reduced (20% of normal) states. The ItL-BHGA is due to the increase in permeability of the neuromembrane to K+(K(+)-dependent) and is neither Na(+)- nor Cl-(-)-dependent. K(+)-channel blockers, a mixture of tetraethyl-ammonium (TEA) and 4-amino-pyridine (4-AP), blocked ItL-BHGA mainly in a noncompetitive and partly in an uncompetitive manner. 3. Unexpectedly, ItL-BHGA of v-LCDN was almost abolished in the Na+o-free state and significantly reduced in the Cl-o-free state. However, an Na(+)-channel blocker, tetrodotoxin, showed a tendency to enhance ItL-BHGA. On the other hand, ItL-BHGA was enhanced in K+o-free state. 4. Ouabain markedly inhibited ItL-BHGA in both noncompetitive and uncompetitive manners. Benzamil, an inhibitor of the Na(+)-Ca2+ exchange applied simultaneously with ouabain could not prevent ouabain inhibition on ItL-BHGA. The currents induced by other putative neurotransmitters, including a K(+)-dependent Iout caused by dopamine on v-LCDN, were not affected by ouabain. 5. According to our previous study, the threo-L-BHGA receptors are not linked with protein kinases or calmodulin. Then, ItL-BHGA could be produced by the receptor K+ channel complex or the receptor-G-protein-K+ channel combination. The present results indicate that the ATPase activity inhibited by ouabain and the presence of extracellular Na+ and Cl- are needed for threo-L-BHGA to activate the K(+)-dependent structure. Furthermore, the K+o-free state, which inactivates the Na(+)-K+ pump, and tetrodotoxin, which suppresses the Na+ channel at least partly, did not affect the structure to be activated.

4-Aminopyridine↗
PubMed1997

Modulation by APGW-amide, an Achatina endogenous inhibitory tetrapeptide, of currents induced by neuroactive compounds on Achatina neurons: amines and amino acids.

1. Modulatory effects of APGW-amide (Ala-Pro-Gly-Trp-NH2), proposed as an inhibitory neurotransmitter of Achatina neurons, perfused at 3 x 10(-6) M on the currents induced by small-molecule putative neurotransmitters were examined by using Achatina giant neuron types, v-RCDN (ventral-right cerebral distinct neuron), TAN (tonically autoactive neuron) and RAPN (right anterior pallial nerve neuron), under voltage clamp. These putative neurotransmitters were ejected locally to the neuron by brief pneumatic pressure. 2. Outward current (Iout) induced by erythro-beta-hydroxy-L-glutamic acid (erythro-L-BHGA) on v-RCDN, which was probably K+ dependent, was enhanced with membrane conductance (g) increase under APGW-amide. From dose (pressure duration)-response curves of erythro-L-BHGA measured in physiological solution (control curve) and with APGW-amide (drug curve), ED50 values of the two curves were nearly comparable, whereas Emax of the drug curve was significantly larger than that of the other. From a Lineweaver-Burk plot of these data, the cross point of the control line and the drug line was on the abscissa. 3. K(+)-dependent Iout caused by dopamine (DA) on v-RCDN was inhibited with a g increase by APGW-amide. The inhibition of this current caused by APGW-amide was mainly in a noncompetitive and partly uncompetitive manner. 4. 5-Hydroxytryptamine (5-HT) produced an inward current (Iin) with two (fast and slow) components on TAN, which was probably Na+ dependent. The fast component of the Iin was inhibited by APGW-amide. The inhibition was mainly in a noncompetitive manner. 5. The currents induced by acetylcholine, gamma-aminobutyric acid and L-glutamic acid on Achatina neuron types were not affected by APGW-amide. 6. The inhibitory effects of APGW-amide on the Iin (fast component) induced by 5-HT were nearly equipotent or a bit stronger than those on the Iout caused by DA. 7. The g increase produced by APGW-amide would be a cause for inhibiting the Iout induced by DA. In addition, we consider that APGW-amide affects intracellular signal transduction systems or ionic channels, thus modulating these currents.

Animals↗
PubMed1997

Modulation by APGW-amide, an Achatina endogenous inhibitory tetrapeptide, of currents induced by neuroactive compounds on Achatina neurons: peptides.

1. Modulatory effects of APGW-amide (Ala-Pro-Gly-Trp-NH2), proposed as an inhibitory neurotransmitter of Achatina neurons, perfused at 3 x 10(-6) M on the currents induced by neuroactive peptides, ejected by brief pressure, were examined by using Achatina giant neuron types, v-RCDN (ventral-right cerebral distinct neuron) and PON (periodically oscillating neuron), under voltage clamp. 2. Outward current (Iout) caused by FMRFamide (Phe-Met-Arg-Phe-NH2) on v-RCDN, which was probably K+ dependent, was inhibited with membrane conductance (g) increase by APGW-amide. From the dose (pressure duration)-response curves of FMRFamide and a Lineweaver-Burk plot of these data, the inhibition caused by APGW-amide was mainly in an uncompetitive manner. 3. Iout caused by APGW-amide on v-RCDN, which was probably K+ dependent, was inhibited with g increase by APGW-amide. The inhibition caused by APGW-amide was partly in a competitive manner and partly in a noncompetitive manner. 4. Iout caused by [Ser2]-Mytilus inhibitory peptide, [Ser2]-MIP (Gly-Ser-Pro-Met-Phe-Val-NH2) on v-RCDN, which was probably K+ dependent, was inhibited with g increase by APGW-amide. Because the modulation of this current was not so marked, a dose-response study of this compound was not carried out. Iin induced by oxytocin on PON was not affected by APGW-amide. 5. From the dose-response curves of APGW-amide, perfused consecutively, the inhibitory effects of APGW-amide on the Iout caused by APGW-amide were stronger than those on the Iout caused by FMRFamide. 6. The inhibition of the APGW-amide-induced Iout on v-RCDN by APGW-amide was partly due to the competition in the receptor sites and partly to the g increase. The inhibition by APGW-amide on the Iout induced by FMRFamide and [Ser2]-MIP would be partly due to the g increase. In addition, we consider that APGW-amide affects intracellular signal transduction systems or ionic channels, thus modulating these currents. 7. The currents modulated by APGW-amide were different from those modulated by achatin-1, another Achatina endogenous neuroexcitatory peptide. We consider that the mechanisms underlying the modulatory effects of APGW-amide are different from those of achatin-I.

Animals↗
PubMed1997

Measurement of a cross-sectional area of normal and stenotic arteries with videodensitometric quantitative arteriography and intravascular ultrasound.

RATIONALE AND OBJECTIVES: A videodensitometric technique that allows measurement of absolute cross-sectional area of any complex lesion was compared with an intravascular ultrasound (US) technique. METHODS: Stenotic devices (10-15 mm long) with cross sections of different shapes were placed in the distal aortas of five anesthetized pigs (weight, 40-50 kg). The stenotic devices were imaged by using an intravascular US probe after power injection of contrast material. RESULTS: A comparison of actual areas and measured cross-sectional areas of the stenotic devices showed that videodensitometry and intravascular US produced better results than edge-detection techniques for both unsubtracted and temporal subtraction images. CONCLUSION: These data suggest that the videodensitometric technique can be used to measure absolute cross-sectional areas of arteries with different shapes.

Absorptiometry, Photon↗