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M C Chang

Publications and source records attributed to M C Chang.

At least 127 records · Page 7Linked to original sources
PubMed1997

N-arachidonylethanolamine (anandamide) formation from N-arachidonylphosphatidylethanolamine in rat brain membranes.

Labeled L-N-arachidonylphosphatidylethanolamine (L-N-arachidonyl PE), a likely precursor of N-arachidonylethanolamine (anandamide), as well as its D-isomer, were synthesized using [14C]arachidonic acid. Anandamide was formed by incubating L-N-arachidonyl PE and rat brain membrane with phenylmethylsulfonyl fluoride (PMSF), an inhibitor of anandamide amidohydrolase. Formation of anandamide from L-N-arachidonyl PE was inhibited by p-chloromercuriphenylsulfonic acid (p-CMPS), sulfhydryl reagent, and heat inactivate pre-treatment. D-N-Arachidonyl PE, an unnatural analog for N-arachidonyl PE, did not form anandamide.

Animals↗
PubMed1997

One-stage reconstruction of skin defect and patellar tendon rupture after total knee arthroplasty. A new technique.

A case is presented herein in which infected total knee arthroplasty associated with a skin defect and patellar tendon rupture was reconstructed with lateral gastrocnemius-Achilles tendon complex after infection was controlled. The results were satisfactory, and the technique proposed herein is highly promising for treating such complicated circumstances after total knee arthroplasty, as not reported previously.

Aged↗
PubMed1997

Changes in cerebral acyl-CoA concentrations following ischemia-reperfusion in awake gerbils.

Transient global cerebral ischemia affects phospholipid metabolism and features a considerable increase in unesterified fatty acids. Reincorporation of free fatty acids into membrane phospholipids during reperfusion following transient ischemia depends on conversion of fatty acids to acyl-CoAs via acyl-CoA synthetases and incorporation of the acyl group into lysophospholipids. To study the effect of ischemia-reperfusion on brain fatty acid and acyl-CoA pools, the common carotid arteries were tied for 5 min in awake gerbils, after which the ligatures were released for 5 min and the animals were killed by microwave irradiation. Twenty percent of these animals (two of 10) were excluded from the ischemia-reperfusion group when it was demonstrated statistically that brain unesterified arachidonic acid concentration was not elevated beyond the range of the control group. Brain unesterified fatty acid concentration was increased 4.4-fold in the ischemic-reperfused animals, with stearic acid and arachidonic acid increasing the most among the saturated and polyunsaturated fatty acids, respectively. The total acyl-CoA concentration remained unaffected, indicating that reacylation of membrane lysophospholipids is maintained during recovery. However, there was a substantial increase in the stearoyl- and arachidonoyl-CoA and a marked decrease in palmitoyl- and docosahexaenoyl-CoA. These results suggest that unesterified fatty acid reacylation into phospholipids is reprioritized according to the redistribution in concentration of acyl-CoA molecular species, with incorporation of stearic acid and especially arachidonic acid being favored.

Acyl Coenzyme A↗
PubMed1997

Cardiac preload, splanchnic perfusion, and their relationship during resuscitation in trauma patients.

INTRODUCTION: Low gastric intramucosal pH (pHi) after shock resuscitation is associated with organ dysfunction and death in trauma patients. However, the relationship between hemodynamic performance, global oxygen transport, and pHi is unclear. Our purpose was to evaluate the relationship between intravascular volume status, splanchnic hypoperfusion, and outcome after shock resuscitation in trauma patients. DESIGN/SETTING: Cohort study of 79 consecutive critically ill patients at a Level I trauma center stratified by normal (NORM, > or = 7.32) or low (LOW, < 7.32) pHi when lactate normalized (< 2.2 mmol/L). MAIN OUTCOME MEASURES: Differences during resuscitation in mean values of right ventricular end-diastolic volume index (RVEDVI), pulmonary artery occlusion pressure, cardiac index, oxygen delivery index, and oxygen consumption index. The incidence of multiple organ failure and death in the NORM and LOW groups were analyzed via odds ratio and chi 2. RESULTS: Patients in the NORM group (n = 45) had a lower incidence of multiple organ failure (4 of 45 vs. 11 of 34, odds ratio 5.0, p < 0.01) and death (5 of 45 vs. 11 of 34, odds ratio 3.8, p < 0.05) than patients in the LOW group (n = 34). NORM patients had a higher initial RVEDVI (116 +/- 31 vs. 95 +/- 25 mL/m2, p < 0.001) and maintained a significantly higher RVEDVI (114 +/- 27 vs. 97 +/- 17 mL/m2, p = 0.003) throughout resuscitation than the LOW group did. There were no differences in the other studied variables. CONCLUSIONS: Supranormal levels of preload during shock resuscitation are associated with better outcome. Maintaining a RVEDVI higher than 100 mL/m2 during shock resuscitation may be of benefit in critically injured patients.

Adult↗
PubMed1997

Clinical application of ventricular end-systolic elastance and the ventricular pressure-volume diagram.

The ability to clinically assess myocardial contractility in a load-independent fashion facilitates the selection of appropriate inotropes, when needed, during shock resuscitation. Within the framework of the ventricular pressure-volume diagram, the slope of the ventricular end-systolic pressure-volume relationship (expressed as ventricular end-systolic elastance, Ees), has been shown to accurately reflect ventricular inotropic state, and to be insensitive to loading conditions. It has not, however, been widely used at the bedside. Our goal was to evaluate the clinical utility of Ees and the ventricular pressure-volume diagram as bedside methods of hemodynamic assessment. We performed a prospective study of 123 hemodynamic interventions in 100 trauma patients during shock resuscitation in which contractility (Ees), preload (left ventricular end-diastolic volume index), and afterload (effective arterial elastance) were calculated before and after addition of inotropes, fluid bolus, and afterload reduction. Mean values of each variable were compared before and after each type intervention using the paired t test. The ventricular pressure-volume diagram was used to predict changes in the studied variables, and the experimental results were compared with predicted changes. Ees (mmHg/mL/m2) increased significantly with inotropes (4.7 +/- 3.2 to 10 +/- 8.7, p < .0001), but was not affected by clinically significant fluid administration (7.0 +/- 4.7 to 8.3 +/- 8.0, p = .10) or afterload reduction (9.6 +/- 5.2 to 9.2 +/- 4.7, p = .72). Left ventricular end-diastolic volume index (mL/m2) improved with fluid administration (54 +/- 8.9 to 62 +/- 9.8, p < .0001) and effective arterial elastance (mmHg/mL/m2) decreased with afterload reduction (3.3 +/- .9 to 2.6 +/- .7, p < .0001). We conclude that Ees is a load-independent measure of contractility, which is measurable at the bedside. The pressure-volume diagram is a useful method of monitoring hemodynamic changes associated with interventions during shock resuscitation.

Adult↗
PubMed1997

Cloning and sequence analysis of a novel hemolysin gene (vllY) from Vibrio vulnificus.

A gene (vllY) encoding a novel hemolysin of Vibrio vulnificus CKM-1 has been cloned and sequenced. When the vllY gene was expressed in minicells, a unique peptide of approximately 40 kDa was identified. Subcellular fractionation of Escherichia coli cells carrying the vllY gene indicated that the VllY protein was distributed in both the cytoplasmic and the periplasmic fractions, with the notable ability to appear in the latter compartment. Nucleotide sequence analysis predicted a single open reading frame of 1,071 bp encoding a 357-amino acid polypeptide with an estimated pI of 5.02. The deduced amino acid sequence of VllY showed high similarity to the sequence of legiolysin, responsible for hemolysis, pigment production, and fluorescence in Legionella pneumophila. The enzyme also exhibited sequence homology to the MelA protein sequence of Shewanella colwelliana and the sequences of 4-hydroxyphenylpyruvate dioxygenase family proteins from various organisms. PCR screening and Southern blotting of V. vulnificus strains revealed that all of the 41 V. vulnificus clinical isolates contained vllY-like genes.

Amino Acid Sequence↗
PubMed1997

Plasmids isolated from marine sediment microbial communities contain replication and incompatibility regions unrelated to those of known plasmid groups.

Two hundred ninety-seven bacteria carrying plasmids that range in size from 5 to 250 kb were identified from more than 1,000 aerobic heterotrophic bacteria isolated from coastal California marine sediments. While some isolates contained numerous (three to five) small (5- to 10-kb) plasmids, the majority of the natural isolates typically contained one large (40- to 100-kb) plasmid. By the method of plasmid isolation used in this study, the frequency of plasmid incidence ranged from 24 to 28% depending on the samples examined. Diversity of the plasmids occurring in the marine sediment bacterial populations was examined at the molecular level by hybridization with 14 different DNA probes specific for the incompatibility and replication (inc/rep) regions of a number of well-characterized plasmid incompatibility groups (repB/O, FIA, FII, FIB, HI1, HI2, I1, L/M, X, N, P, Q, W, and U). Interestingly, we found no DNA homology between the plasmids isolated from the culturable bacterial population of marine sediments and the replicon probes specific for numerous incompatibility groups developed by Couturier et al. (M. F. Couturier, F. Bex, P. L. Bergquist, and W. K. Maas, Microbiol. Rev. 52:375-395, 1988). Our findings suggest that plasmids in marine sediment microbial communities contain novel, as-yet-uncharacterized, incompatibility and replication regions and that the present replicon typing system, based primarily on plasmids derived from clinical isolates, may not be representative of the plasmid diversity occurring in some marine environments. Since the vast majority of marine bacteria are not culturable under laboratory conditions, we also screened microbial community DNA for the presence of broad- and narrow-host-range plasmid replication sequences. Although the replication origin of the conjugally promiscuous broad-host-range plasmid RK2 (incP) was not detectable in any of the plasmid-containing culturable marine isolates, DNA extracted from the microbial community and amplified by PCR yielded a positive signal for RK2 oriV replication sequences. The strength of the signal suggests the presence of a low level of the incP replicon within the marine microbial community. In contrast, replication sequences specific for the narrow-host-range plasmid F were not detectable in DNA extracted from marine sediment microbial communities. With the possible exception of mercuric chloride, phenotypic analysis of the 297 plasmid-bearing isolates did not demonstrate a correlation between plasmid content and antibiotic or heavy metal resistance traits.

Basidiomycota↗
PubMed1997

Ultrasound-guided fine needle aspiration biopsy in the diagnosis of chronic pulmonary infection.

Fourteen patients, with abnormalities on their chest radiographs found over a period of > or = 4 weeks and diagnosed as chronic pulmonary infections in the follow-up, underwent ultrasound-guided fine-needle aspiration biopsy (US-guided FNAB). Six patients also underwent color Doppler ultrasound examination before needle aspiration biopsy. Nine patients had a confirmed diagnosis [tuberculosis (n = 1), cryptococcosis (n = 3), actinomycosis (n = 2), and aspergillosis (n = 1)] or a suggestive diagnosis [caseating granulomatous inflammation (n = 1) and caseous necrosis (n = 1)] made after US-guided FNAB. The remaining 5 patients were finally diagnosed by US-guided large-bore cutting biopsy (n = 1, tuberculosis) and surgical resection [aspergillosis and organized pneumonia (n = 1), mucormycosis and organized pneumonia (n = 1), penicillium infection and organized pneumonia (n = 1), and cryptococcosis (n = 1)]. In 8 patients receiving gray scale US examination only, complications developed in 2 patients after US-guided FNAB [minimal pneumothorax (n = 1) and hemoptysis (n = 1)]. Of the 6 patients who also underwent color Doppler US examination, 4 had detectable blood vessels within the lesion. Thus, the site for US-guided FNAB was changed in 2 patients to prevent injury to prominent blood vessels. There were no complications observed following color Doppler US examination. We conclude that US-guided FNAB is useful for diagnosing chronic pulmonary infections, and color Doppler US is valuable for preventing injury to blood vessels.

Adult↗
PubMed1997

Sand aspiration with near-drowning. Radiographic and bronchoscopic findings.

Sand and foreign-body aspiration may accompany drowning and near-drowning, but few details regarding such patients are available in the literature. We report a 26-yr-old woman who suffered near-drowning after a motor-vehicle accident. Initial attempts at ventilation were compromised by increased peak airway pressures, which decreased following the removal of large amounts of sand from the patient's endotracheal tube. Chest radiographs and computed tomographic (CT) scans of the patient obtained upon her arrival in the emergency department demonstrated sand bronchograms within the lower lobes of both lungs, and sand within the maxillary sinuses and stomach. We present the radiographic, bronchoscopic, and microbiologic findings within hours after this patient's accident, with a review of the literature and provisional recommendations for the management of such patients.

Accidents, Traffic↗
PubMed1997

Incorporation of [U-14C]palmitate into rat brain: effect of an inhibitor of beta-oxidation.

We examined the effect of a clinically therapeutic dose of methyl 2-tetradecylglycidate (McN-3716, methyl palmoxirate, MEP) (2.5 mg/kg), an inhibitor of beta-oxidation of fatty acids, on incorporation of radiolabeled palmitic acid ([U-14C]PAM) from plasma into brain lipids of awake rats. Four hour pretreatment with 2.5 mg/kg MEP significantly increased the incorporation of [U-14C]PAM into brain lipids and substantially decreased aqueous radiolabeled metabolites in brain that can constitute unwanted background signal when analyzed by quantitative autoradiography. MEP treatment increased the lipid to aqueous background radioactivity from 0.8 to 3.0. Net rate of incorporation, k*, was significantly increased (60%) by MEP and was attributed to incorporation of [U-14C]PAM into phospholipid and triglyceride brain compartments. MEP treatment did not affect the size of the fatty acyl-CoA pool or the distribution of the various molecular acyl-CoA species. These results indicate that MEP, at a dose of 2.5 mg/kg (per os), can be used to increase incorporation of [1-(11C)]PAM for studying brain lipid metabolism in humans by positron emission tomography (PET).

Acyl Coenzyme A↗
PubMed1997

Optimal surgical strategy for potentially curable serosa-involved gastric carcinoma with intraperitoneal free cancer cells.

BACKGROUND: Radical gastrectomy with systematic lymphadenectomy (RG) remains controversial in the treatment of gastric carcinoma. On the other hand, the prognosis of gastric carcinoma, in the presence of intraperitoneal free cancer cells, is poor. The optimal surgical strategy for serosa-involved gastric carcinoma with intraperitoneal free cancer cells remains undefined. STUDY DESIGN: A prospective study of intraperitoneal cytologic washing was conducted on 134 patients with potentially curable serosa-involved gastric carcinoma who underwent RG. During the same period, 28 patients with resectable tumors who received palliative simple gastrectomies because of the presence of gross incurable conditions (eg, multiple hepatic metastases, peritoneal carcinomatosis, or extra-abdominal metastasis) were used as controls. RESULTS: Intraperitoneal free cancer cells were found in 26 patients (19.4 percent). Compared with the remaining 108 patients without free cancer cells, there were no significant differences in the clinicopathologic characteristics and pathologic stages. No patients died after palliative resection, but five patients died after RG. The patients with free intraperitoneal free cancer cells had a poorer long-term prognosis after RG than those without free cancer cells (p < 0.0001). The prognosis for such patients was similar to the prognosis of those who underwent palliative resection. CONCLUSIONS: A peritoneal washing cytologic examination is mandatory before resection for potentially curable serosa-involved gastric carcinoma. When free cancer cells appear in the washing fluid, the cancer is incurable. Simply gastrectomy without additional lymphadenectomy is the optimal strategy for treatment.

Aged↗
PubMed1997

Mouse skin damage caused by a recombinant extracellular metalloprotease from Vibrio vulnificus and by V. vulnificus infection.

Vibrio vulnificus wound infection is characterized by an intense acute cellulitis which spreads along the subcutaneous tissue with severe tissue destruction. Toxins produced by the bacteria appear to be involved in the pathogenesis of skin necrosis and to facilitate microbial dissemination in vivo. We report microscopic studies of mouse skin damage caused by a single intradermal injection of V. vulnificus or of an extracellular metalloprotease isolated from this organism. The gene encoding this metalloprotease has been cloned and expressed in Escherichia coli. The crude metalloprotease extract obtained from the periplasmic fraction by osmotic shock was used in this study. Intradermal injection of this preparation resulted in marked edematous changes of the skin, which extended throughout the dermis and subcutaneous tissues and into adjacent muscles. The collagen and elastic fibers degenerated and some muscle cells even appeared necrotic. Blood vessels became congested, with moderate perivascular neutrophil and mononuclear cell infiltration. There was no evidence of necrotic changes in the blood vessel itself. These results show that the damage to the connective tissues caused by V. vulnificus is at least partly attributable to its protease. Therefore, the protease seems to be an important virulence factor of this microbe.

Animals↗
PubMed1997

Intraosseous epidermoid cyst in distal phalanx of finger: a case report.

Bone tumor in distal phalanx of finger is rare. Differential diagnosis includes glomus tumor with bone erosion, enchondroma, osteomyelitis, aneurysmal bone cyst and metastasis. We herein present a case with intraosseous epidermoid cyst in distal phalanx which has rarely been reported.

Bone Diseases↗
PubMed1997

Core decompression in treating ischemic necrosis of the femoral head.

BACKGROUND: The application of core decompression in the treatment of ischemic necrosis of femoral head (INFH) is to preserve the joint at early stage of the disease. Although excellent results have been obtained in many series, its effectiveness is questionable because of high rates of failure. This study is to evaluate the effectiveness of this technique in our patients with INFH receiving core decompression as the sole treatment. METHODS: Although 91 patients were treated with core decompression in Veterans General Hospital-Taipei from 1980 to 1993, only 71 were considered as the valid cases after having been followed for 24 to 165 months (mean 56.7 months). Of 84 hips treated, 49 hips were steroid induced, 20 idiopathic, 14 alcohol related, and one related to trauma. Twenty-five hips were at Steinberg stage I, 32 at stage II, nine at stage III, 17 at stage IV, and one at stage VI. RESULTS: The results were poor in 22 (26.19%) hips since the patients required hip prosthesis. Fair results were rated in 37 (44.05%) hips since progressive collapse occurred in the femoral head and the patients suffered from moderate hip pain. Good results were found in nine (10.71%) hips since the lesion showed no progression and the patients had only occasional pain. Excellent results were obtained in 16 (19.05%) hips since the patients had no pain and the lesion had no progressive change. The satisfactory rate in the nonsteroid-related hips (33% or 12/35) was significantly higher than in the steroid-related hips (27% or 13/49). The overall satisfactory result was only 30%. CONCLUSIONS: Although core decompression may not be effective in preventing progression of INFH, it may relieve temporary pain and delays the need for hip arthroplasty in some patients.

Adolescent↗
PubMed1996

Lithium decreases turnover of arachidonate in several brain phospholipids.

In vivo rates of incorporation and turnover of palmitate and arachidonate in brain phospholipids were measured in awake rats treated chronically with lithium, following intravenous infusion of radiolabeled palmitate and arachidonate, respectively. Chronic lithium, at a brain level considered to be therapeutic in humans, decreased turnover of arachidonate within brain phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine by up to 80% (P < 0.001). In contrast, lithium had a minimal effect on turnover of palmitate, causing only a 26% reduction in turnover in phosphatidylcholine (P < 0.01). These results suggest that a major therapeutic effect of lithium is to reduce turnover specifically of arachidonate, possibly by inhibiting phospholipase A2 involved in signal transduction. The effect may be secondary to the known action of lithium on the phosphoinositide cycle, by inhibiting the activity of inositol monophosphatase.

Animals↗
PubMed1996

In vivo imaging of cortical membrane remodeling in rats with chronic unilateral ablation of nucleus basalis magnocellularis: use of radiolabeled palmitic acid.

Membrane remodeling was imaged in vivo in brains of rats with a 2-week-old right-sided ablation of the nucleus basalis magnocellularis (NBM). To do this, [9,10-3H]palmitic acid ([3H]PAM) was injected intravenously and regional brain incorporation k* of tracer was determined with quantitative autoradiography after 20 min circulation. In NBM-lesioned animals, k* was elevated significantly (by up to 17%) in 11 ipsilateral frontal or parietal cortical regions, more so in layer 1 than in layers IV and V. Unoperated animals showed no right-left difference in k*, whereas sham-operated animals showed some unilateral effects of damage due to the needle track. Circulating [3H]PAM is incorporated into sn-1 positions of brain phospholipids, mainly phosphatidylcholine, and its rate of turnover is thought to reflect turnover of neuronal and glial membranes. These results, when related to published evidence of altered cortical phospholipid metabolism in NBM-lesioned rats, suggest that images of increased [3H]PAM incorporation into ipsilateral cortex reflect increased membrane remodeling involving phospholipids.

Animals↗
PubMed1996

Integrin alpha v beta 3 and phospholipase C regulate prostacyclin formation of endothelial cells caused by ancrod-generated fibrin.

Ancrod-generated fibrin has been shown to stimulate prostacyclin synthesis of human umbilical vein endothelial cells (Chang et al., 1994, Biochem. Biophys. Res. Commun. 203, 1920). We further investigated its mechanism of action. The increment of 6-keto prostaglandin F1 alpha stimulated by ancrod-generated fibrin was almost completely inhibited when endothelial cells were either pretreated with 50 microM 8-(N,N'-diethylamino)octyl-3,4,5- trimethoxybenzoate (TMB-8) or preloaded with 15 microM 1,2-bis(2- aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). 6-Keto prostaglandin F1 alpha production during 2 and 10 h incubation period was also inhibited by 1.2 mM ethyleneglycol-bis-(beta-aminoethylether)-N,N,N',N'-tetraace tic acid (EGTA) (41 +/- 12 and 53 +/- 17% inhibition, respectively). Further, ancrod-generated fibrin caused a rapid-onset increase in [3h]inositol monophosphate (IP1) formation in endothelial cells. This increase in IP1 was significantly inhibited by 1 mM Gly-Pro-Arg-Pro, 1 mM neomycin or 100 ng/ml pertussis toxin. At the same time, neomycin and pertussis toxin also significantly inhibited 6-keto prostaglandin F1 alpha synthesis of endothelial cells stimulated by ancrod-generated fibrin. Additionally, the increment of IP1 production as well as prostacyclin production were significantly inhibited by monoclonal antibodies directed against alpha v beta 3. These results suggest that intra- and extra-cellular Ca2+ participate in prostacyclin synthesis stimulated by ancrod-generated fibrin. Ancrod-generated fibrin stimulates pertussis toxin-sensitive G-protein regulated phosphoinositide breakdown, which is responsible for prostacyclin synthesis. This augmentation in prostacyclin synthesis and phosphoinositide breakdown caused by ancrod-generated fibrin area, at least in part, mediated by fibrin binding to integrin alpha v beta 3 on endothelial cells.

6-Ketoprostaglandin F1 alpha↗