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C C Lu

Publications and source records attributed to C C Lu.

At least 91 records · Page 5Linked to original sources
PubMed1995

Schedule-induced polydipsia increased both mesotelencephalic-dopaminergic and pontine-noradrenergic activities in the rat brain.

We have demonstrated previously that the activity of schedule-induced polydipsia (SIP) was persistently depressed after successive lesions of the bilateral symmetrical locus coeruleus and the ventral tegmental area. The hypothesis that central catecholaminergic neurons mediate animal behaviors in arousal or coping processes, e.g., SIP, was tested by the demonstration of concomitant changes of transmissions in regions of appropriate nerve terminals. By using the high performance liquid chromatography coupled with electrochemical detection methods, the current experiments were designed to examine the regional turnover of monoamines in the performance of SIP of the control rats by measurements of the biochemical derivatives including dopamine (DA), norepinephrine (NE), serotonin (5-HT), 3,4-dihydroxyphenylacetic acid (DOPAC), dihydroxyphenylalanine (DOPA), 4-hydroxy-3-methoxyphenylglycol-4-sulfate (MHPG-SO4) and 5-hydroxyindoleacetic acid (5-HIAA). It was found that rats in the performance of SIP, the DA levels and DA synthesis and utilization in the limbic area were increased and that the NE level and NE synthesis in the several pontine NE projected areas, e.g., limbic area, hippocampus, cortex and pons were also increased. Conversely, both NE and 5-HT metabolism in the hippocampus and the cortex were decreased. We concluded that the enhanced actions of the DA-limbic system and NE-pontine system in the rats are both important for the maintenance of SIP performance.

Animals↗
PubMed1995

Diminished actin polymerization of neonatal neutrophils determined by a microvolume whole blood method.

To investigate the actin response to chemotactic stimulation of neonatal neutrophils, we developed a new procedure to measure neutrophil F-actin content directly in microvolume whole blood (100 microliters sample each test). Using this procedure, we compared neutrophil actin response to N-formyl-methyonyl-leucyl-phenylalanine (FMLP) between groups of normal neonate and adult volunteers. Relative F-actin content (FMLP/control ratio) of neonatal neutrophils is significantly lower than those of adult volunteers' neutrophils both at 30 sec (1.94 +/- 0.34 vs. 2.25 +/- 0.31; n = 16, p < 0.05, t test) and 60 sec (2.23 +/- 0.19 vs. 2.40 +/- 0.27; n = 16, p < 0.05, t test) after FMLP stimulation. These results provide new evidence of impairment of neutrophil actin response in the neonate, which may partially explain the observed chemotactic defect in neonatal neutrophils.

Actins↗
PubMed1994

Calcitonin inhibits testosterone and luteinizing hormone secretion through a mechanism involving an increase in cAMP production in rats.

Effects of calcitonin peptides, including human calcitonin (hCT), salmon calcitonin (sCT), and calcitonin gene-related peptide (CGRP), on the secretion of testosterone and luteinizing hormone (LH) in male rats were studied. Male rats were injected intravenously with human chorionic gonadotropin (hCG), calcitonin peptides, or hCG plus calcitonin peptides. Blood samples were collected at several intervals following hormone challenge. In an in vitro experiment, testis blocks were incubated with hCG (0, 0.05, 0.5, or 5 IU/ml) or hCG (0.5 IU/ml) plus calcitonin peptides (0-10(-9) or 10(-6) M) at 34 degrees C for 30 minutes. Both medium and plasma samples were extracted by ether and analyzed for testosterone by radioimmunoassay (RIA). The concentration of calcium in each plasma sample was measured by an automatic calcium analyzer. The anterior pituitary gland (AP) was incubated with or without calcitonin peptides (0-10 nM) at 37 degrees C for 30 minutes. They were then incubated with gonadotropin releasing hormone (GnRH, 10 nM) for a further 30 minutes. The concentration of LH in AP medium was measured by RIA. The accumulation of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in both testicular tissues and APs were measured by RIA. A single intravenous injection of calcitonin peptides decreased the basal and hCG-stimulated levels of plasma testosterone gradually from 60 to 180 or 360 minutes after challenge. The plasma calcium was not altered by the injection of calcitonin peptides and/or hCG. Administration of calcitonin peptides in vitro resulted in a dose-dependent inhibition of both basal and hCG-stimulated release of testosterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in Chinese infants with or without severe neonatal hyperbilirubinaemia.

To characterize mutations in the glucose-6-phosphate dehydrogenase (G6PD) gene in Chinese infants, we studied 213 G6PD-deficient infants without blood exchange transfusion (BET) therapy, and 34 patients who required BET therapy for their severe hyperbilirubinaemia after birth. Nine different point mutations were characterized in all infants. Of these mutations, the G to T substitution at cDNA nucleotide (nt) 1376, which accounts for the mutations in 131 (53.0%) neonates, followed by G to A substitution at nt 1388 in 18 (10.5%) infants, A to G substitution at nt 493 in 17 (6.9%) infants, A to G substitution at nt 95 in 10 (4.1%) infants, C to T substitution at nt 1024 in six (2.4%) infants, and G to T substitution at nt 392 in three (1.2%) infants, G to A substitution at nt 487 in two (0.8%) infants, C to T substitution at nt 1360 in two (0.8%) infants and C to T substitution at nt 592 in two (0.8%) infants. Mutations in 48 (19.5%) G6PD-deficient infants were not characterized. Most (64.7%) mutations in the G6PD-deficient infants who required BET therapy after birth result from a G to T substitution at nt 1376. The enzyme activity of G6PD deficient infants who required BET therapy is significantly lower than for those who did not, even in a group with the same variant (as in 1376 mutation). Severe neonatal jaundice requiring BET therapy can take place with the majority of variants encountered in this area.

Base Sequence↗
PubMed1994

Ectopic gastric mucosa in the upper esophagus: detection and radiographic findings.

PURPOSE: To detect and characterize the appearance of islands of ectopic gastric mucosa in the upper esophagus at routine examination of the upper gastrointestinal (GI) tract. MATERIALS AND METHODS: Well-distended upper esophagus was documented with spot radiographs obtained with routine double-contrast examination performed after administration of high-density barium in nine patients. Detected lesions were confirmed by means of endoscopy and biopsy. RESULTS: Twelve lesions were detected. Radiographic findings were characterized by either a discrete, shallow depression surrounded by a subtle, rimlike elevation on double-contrast images or by a pair of small indentations on the same wall on full-column, single-contrast images at the level of the thoracic inlet. Endoscopic examination revealed well-circumscribed areas of reddish mucosa located 15-26 cm from the incisors. CONCLUSION: Ectopic gastric mucosa in the upper esophagus is easily demonstrated at routine examination of the upper GI tract. Diagnosis can be based on location and characteristic radiographic appearance.

Adult↗
PubMed1994

Effect of human calcitonin on the secretion of luteinizing hormone in orchiectomized rats.

The effect of human calcitonin (hCT) on the secretion of luteinizing hormone (LH) was examined in castrated rats. Male rats were orchiectomized (Orch) 2 weeks before they were treated with a single bolus injection of gonadotropin-releasing hormone (GnRH, 1 microgram/kg of body weight), hCT (3.4 ng/kg), or the combination of GnRH and hCT through a right jugular vein catheter. Blood samples (0.5 ml each time) were collected immediately before (0-min) and then at 15, 30, 60, 120 and 180 min after hormone injection. Plasma LH concentration was measured with a radioimmunoassay technique. Plasma calcium concentration was determined in an automatic analyzer. hCT significantly diminished both the basal and GnRH-stimulated levels of plasma LH without any relation to the reduced plasma levels of calcium. These results clearly demonstrated a plasma calcium-unrelated inhibitory effect of hCT on LH secretion.

Animals↗
PubMed1994

Insulin autoimmune syndrome in a patient with methimazole and carbimazole-treated Graves' disease: a case report.

Insulin autoimmune syndrome (IAS) includes fasting or reactive hypoglycemia, hyperinsulinemia and the presence of insulin-binding antibodies in patients who have never been exposed to exogenous insulin. The report concerns a 34-year-old male patient with Graves' disease who had history of having taken methimazole for two months, without any consequence, 4 years previously. However, when methimazole was again administered for three weeks followed by a week of carbimazole, the patient suffered hypoglycemia 4 times during the next 4 weeks. He denied history of diabetes mellitus (DM), of taking any oral hypoglycemic agent or of having received insulin injection. Laboratory data showed total serum insulin level > 320 microU/mL, free insulin 55 microU/mL and insulin antibody 88.3%. Oral glucose tolerance test (OGTT) revealed DM pattern. Since the patient had history of allergy to anti-thyroid drugs before this event, so he was treated with radioiodine (131I). There was no episode of hypoglycemic attack during 15 months of follow-up.

Adult↗
PubMed1993

The lung contents of endothelin are altered by thyroid hormone status in rat.

Endothelin-1 (ET-1) is a 21-residue peptide isolated from the conditioned medium of cultured porcine endothelial cells and is widely distributed throughout the body, with relatively high levels in the kidney and lung. Animal studies have revealed that the lung appears to have the largest capacity for ET-1 removal from the blood stream. In this study we have examined the possible influence of thyroid status on immunoreactive endothelin (IR-ET) levels in the plasma and lung of the male rats. 3 weeks after the surgical removal of the thyroid gland from male rats, the IR-ET levels in the lung were reduced by 39%. Similarly, IR-ET levels were decreased 46% in the lung of rats rendered hypothyroid by treatment with 0.1% (w/w) PTU in the drinking water for 30 days, and replacement with daily L-thyroxine (T4) injections (5 micrograms/100 g) prevented this decrease. However, thyrotoxicosis induced by daily L-T4 injections (10 micrograms/100 g) also caused a decrease of the lung IR-ET levels by 49%. Nevertheless, the plasma IR-ET levels are similar in each group. Fast protein liquid chromatography study verified the presence of ET-1 immunoreactivity in both rat plasma and lung tissue extracts. This study demonstrates that euthyroid status is required for the maintenance of physiological concentrations of IR-ET in the lung of male rats.

Animals↗
PubMed1993

Purification and amplification of DNA from Penaeus monodon-type baculovirus (MBV).

The purpose of this paper was to purify and amplify the DNA fragment of Penaeus monodon-type baculovirus (MBV). Using 30-50% caesium chloride gradients, MBV virions and occlusion bodies with density parameters of 1.28-1.29 and 1.32-1.33 g/ml, respectively, were purified. Two oligonucleotide primers have been successfully designed and utilized for the amplification of a DNA fragment of MBV. After 35 amplification cycles of the MBV DNA fragment, a large amount of amplified product with an approximate molecular weight of 600 bp was obtained. This is the first successfully published work on the amplification of MBV using the polymerase chain reaction (PCR). Using the same primers, DNA extracted from MBV noninfected P. monodon, P. japonicus, and P. orientalis had a negative PCR response. However, a positive PCR response was obtained from DNA extracted from MBV-infected postlarval P. monodon. DIG-dot blot hybridization technique using PCR product obtained from the present study as a probe further confirmed that the product is originated from a portion of MBV polyhedrin gene. It is also suggested that PCR product may be beneficial for an accurate and early diagnosis of MBV infection in larval shrimp.

Animals↗
PubMed1993

Midgut volvulus as a complication of intestinal malrotation in adults.

Seven adults with midgut volvulus as a complication of malrotation are presented. All patients were men with an average age of 33 years. Four presented with long histories of intermittent abdominal pain. In three patients, the twisted, corkscrew appearance of the barium column in the duodenum and proximal jejunum in an upper gastrointestinal series made the diagnosis. In the remaining patient, small-bowel follow-through performed three years before surgery showed intestinal malrotation. Three patients presented with the acute onset of severe abdominal pain. Plain films showed small-bowel obstruction and pneumatosis intestinalis in two patients and only nearly complete small-bowel obstruction in the third. Barium studies were not done in this group because of the need to proceed to exploratory laparotomy and the risk of perforation. In one patient, abdominal angiography suggested the diagnosis by showing abnormal courses of the mesenteric vessels to the volvulized segment of small bowel. All three of these patients showed ischemic segments of bowel at laparotomy.

Abdomen, Acute↗
PubMed1993

Signal fidelity requirements for deriving impedance cardiographic measures of cardiac function over a broad heart rate range.

Our findings indicate that the impedance cardiogram spectrum extends from DC to 50 Hz. Any amplifier with an upper band limit less than 50 Hz can be expected to produce attenuation and distortion of the impedance cardiogram. This signal attenuation may be systematically enhanced under conditions of high heart rate when a greater proportion of signal energy will be in the upper frequency range of the impedance cardiogram spectrum. Therefore, the present study was designed to assess the influence of amplifier bandwidth on dZ/dtmax, stroke volume, and systolic time intervals (LVET, PEP, QZ, QX). Simultaneously measured delta Z and dZ/dt signals from two impedance cardiographs, with corner frequencies of 120 and 60 Hz for the delta Z and 50 and 15 Hz for dZ/dt channels, were contrasted over a broad range of heart rate (70-150 bpm). In addition to the analog dZ/dt signals obtained from the instruments, the delta Z signals were digitally converted to dZ/dt by off-line digital differentiation with a 50 Hz corner frequency. The results demonstrated that the measurements with the 15 Hz corner frequency, when compared with the 50 Hz corner frequency measurements, systematically attenuated the dZ/dtmax amplitude and stroke volume measurements as heart rate increased. The attenuation of dZ/dtmax and stroke volume ranged from about 13% to 26% as heart rate increased from 70 to 150 bpm. When the upper bandlimit was 50 Hz, the dZ/dt signal had greater resolution of waveform events and produced less prolonged systolic time intervals. The 15 Hz amplifier differentially influenced the B point, Z-peak and X minimum, having no apparent effect on the temporal location of the B point, but delaying the Z-peak about 21.7 ms and the X minimum about 7.4 ms. These findings indicate that impedance cardiographs with insufficient upper bandlimits will differentially influence ICG-derived measurements as heart rate varies.

Adult↗
PubMed1993

Tissue contents of endothelin vary according to thyroid hormone status in rat.

Endothelin-1 (ET-1) is a 21-residue peptide isolated from the conditioned medium of cultured porcine endothelial cells and is widely distributed throughout the body, with relatively high levels in the kidney and lung. In this study we examined the influence of thyroid hormone status on immunoreactive endothelin (ir-ET) levels in the plasma, lung, and kidney tissues of rats. Three weeks after surgical removal of the thyroid gland from male rats, the ir-ET levels in the lung and kidney were reduced by 39% and 42%, respectively. Similarly, ir-ET levels were decreased by 46% in the lung and 45% in the kidney of rats rendered hypothyroid by treatment with 0.1% (wt/wt) n-propylthiouracil (PTU) in the drinking water for 30 days. Replacement with daily L-thyroxine (T4) injections (5 micrograms/100 g) prevented this decrease. However, thyrotoxicosis induced by daily L-T4 injections (10 micrograms/100 g) also caused a decrease of the lung ir-ET levels by 49%, but had no significant effect on the renal ir-ET levels. However, the plasma ir-ET levels were similar in each group. Fast protein liquid chromatography study verified the presence of ir-ET-1 in the plasma and tissue extracts. This study demonstrates that thyroid hormone status affects tissue levels of ir-ET differently and that a euthyroid status is required for the maintenance of physiologic concentrations of ir-ET in the lung of male rats.

Animals↗
PubMed1993

Silicone fluid-induced pulmonary embolism.

Silicone fluid injection for mammary augmentation is a well-known illegal procedure. It has been associated with many complications, including local tissue granulomatous reaction, chronic infection, and sclerosis, but pulmonary involvement in human beings has been documented in only six cases. We describe three more such cases of pulmonary embolism. These three patients were all female, young, and previously healthy. They received the procedures only for cosmetic reasons. Unfortunately, one of them died and another lived with the sequelae of pulmonary fibrosis. The mortality rate of the nine total patients with pulmonary embolism induced by silicone fluid, including our three cases, is 33%. Because of this high mortality rate and long-term sequelae of pulmonary fibrosis, no silicone fluid injection should be given for cosmetic reasons, especially in mammary augmentation in which a large volume of silicone fluid is more likely to be used, and the early use of corticosteroid therapy may be helpful.

Adult↗
PubMed1993

[Applied anatomy of the second dorsal metacarpal artery island flap].

50 specimens of the adult hand were dissected to study the origin, course, anastomosis and supplying area of the second dorsal metacarpal artery. The island fasciocutaneous flap of dorsum of the hand, based on second dorsal metacarpal artery, has been designed for the repair of soft tissue defects in the hand. We have successfully used four neurovascular flaps. The anatomy and clinical use of the axial pattern flap based on the second dorsal metacarpal artery are described.

Adult↗
PubMed1992

Role of locus coeruleus and serotonergic drug actions on schedule-induced polydipsia.

Schedule-induced polydipsia (SIP) poses a general buffering property to reduce the heightened arousal produced by a schedule of intermittent feeding. It thus provides a unique opportunity to study CNS integration in stress-coping reactions. In the present study, we examined the role of the locus coeruleus (LC) and the pharmacological actions of serotonergic (5-HT2) analogs on SIP. Water intake, licking, and bar presses per minute in rats were recorded as indices of SIP activity after they had been subjected to 1-h performance of a fixed-interval 1-min operant pellet conditioning. Our results showed that SIP was progressively decreased after lesions were placed bilaterally in the LC areas and then followed by further lesioning in the bilateral ventral tegmental area. Neurotoxin DSP-4 also had an inhibitory action on the SIP potency. In addition, SIP was attenuated by 2,5-dimethoxy-4-iodoamphetamine (0.1, 0.5, or 1.0 mg/kg, IP), a 5-HT2 agonist, and activated by ritanserin (2.5 mg/kg, IP), a 5-HT2 agonist. After bilateral LC lesions, SIP was attenuated and the activating effect of RIT was abolished. Our data suggest that the LC is involved in the central integration of SIP and that the modulating effects of 5-HT2 receptors on SIP depend upon the integrity of LC function.

Animals↗
PubMed1992

Imaging of the biliary sump syndrome.

Side-to-side choledochoduodenostomy is a safe and effective surgical technique to improve biliary drainage in selected patients. The segment of common bile duct between the anastomosis and the ampulla of Vater may act as a stagnant reservoir or sump. When debris, stones, or infected bile accumulates in the sump, usually because of malfunction of the ampulla of Vater, recurrent abdominal pain or symptoms of cholangitis, pancreatitis, or biliary obstruction may develop. This uncommon (0.14-1.30%) complication is known as the sump syndrome. On imaging studies, diagnostic findings are debris or stone(s) in the common bile duct. Suggestive findings are dilated bile or pancreatic ducts, and changes due to pancreatitis, cholangitis, or liver abscess. Patients with this syndrome frequently have multiple imaging studies before the condition is recognized. The purpose of this essay is to illustrate the imaging findings of this syndrome.

Adult↗
PubMed1992

CT diagnosis of small-bowel obstruction: efficacy in 60 patients.

We retrospectively compared the CT findings in patients with and without surgically proved small-bowel obstruction to evaluate the role of CT in diagnosing the presence and cause of obstruction. In the patients with obstruction, we compared the CT findings with findings on plain abdominal radiographs and contrast studies of the small intestine. CT criteria used for the diagnosis of obstruction were dilated small-bowel loops proximal to the suspected site of obstruction and collapsed or normal-appearing loops of small bowel distal to the obstruction. Receiver-operating-characteristic analysis suggested the optimum balance of sensitivity and specificity was achieved when 2.5 cm was used to indicate dilatation of the small bowel. On the basis of these criteria, the presence of obstruction was correctly diagnosed in 27 (90%) of 30 patients with proved obstruction, and obstruction was not diagnosed in the patients without obstruction. The cause of the obstruction was evident on CT in 14 of the 30 obstructed patients: abscess (five), neoplastic lesion (three), peritoneal carcinomatosis (three), and other (three). Adhesions were responsible for the obstruction in 13 of 15 patients in whom the cause was not shown on CT. In six patients in whom findings on plain abdominal radiographs were normal, the CT scan was positive for obstruction. However, in the three patients whose CT scans were falsely negative for obstruction, findings suggesting obstruction were seen on plain films. Of 15 patients who had both CT and contrast studies of the small intestine, CT offered more information concerning the cause of obstruction in six (40%), primarily by demonstrating significant extraluminal abnormalities. CT and gastrointestinal contrast studies gave concordant results in eight patients with obstruction. In only one patient did the gastrointestinal contrast study give more diagnostic information. We conclude that CT scanning demonstrates accurately the presence of high-grade small-bowel obstruction and may be the technique of choice when extraluminal abnormalities are suspected or when prompt, efficient, and comprehensive evaluation is required.

Adult↗