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Biomedical subjects

C Chao

Publications and source records attributed to C Chao.

At least 55 records · Page 3Linked to original sources
PubMed1996

Sexual dimorphism of cardiovascular responses to early blockade of bradykinin receptors.

To assess whether the cardiovascular effects induced by early blockade of bradykinin B2-receptors with Hoe 140 (D-Arg[Hyp3,Thi5,D-Tic7,Oic8]-bradykinin) are influenced by sex, Wistar rats of both sexes received the antagonist (300 nmol/d per kilogram body wt) or vehicle from 2 days to 7 weeks of age by subcutaneous injection and then by intraperitoneal infusion. Compared with control rats, Hoe 140-treated female rats showed higher systolic blood pressure levels at 7 and 9 weeks of age (125 +/- 2 versus 111 +/- 2 mm Hg and 132 +/- 3 versus 116 +/- 2 mm Hg, respectively, P < .05), whereas in male rats a difference was found at 7 weeks (122 +/- 4 versus 108 +/- 4 mm Hg, P < .05) but not at 9 weeks. At this stage, the mean blood pressure of Hoe 140-treated rats was higher than that of control animals, and this difference was more pronounced at 12 weeks in female rats (121 +/- 2 versus 100 +/- 3 mm Hg in control animals, P < .01) compared with males (116 +/- 3 versus 104 +/- 2 mm Hg in control animals, P < .05). After the first week of life, body weight gain was greater in Hoe 140-treated female rats than in control rats, whereas a group-difference was detected in male rats only after weaning. In Hoe 140-treated female rats, heart weight was already increased at 9 weeks (330 +/- 6 versus 305 +/- 5 mg/100 g body wt in control rats, P < .05), whereas it was necessary to prolong Hoe 140 administration in male rats to develop heart hypertrophy (300 +/- 4 versus 275 +/- 4 mg/100 g body wt in control rats at 12 weeks, P < .05). Tissue kallikrein mRNA levels were higher in the kidney of adult female rats, whereas no sex difference was detected in the heart. The finding of a sexual dimorphism in the cardiovascular response to early blockade of bradykinin receptor suggests that endogenous kinins play a role in the regulation of cardiovascular function in both sexes, but they may be functionally more important in the female rat.

Animals↗
PubMed1995

A role for endothelin ETA receptors in regulation of renal function in spontaneously hypertensive rats.

While there is evidence to suggest that endothelin-1 is involved in regulation of kidney function and blood pressure, the importance of endothelin ETA receptors in this area has not been clearly defined. The novel, non-peptide endothelin ETA receptor antagonist, BMS-182874, (5-(dimethylamino)-N-(3,4- dimethyl-5-isoxazolyl)-1-naphthalene sulfonamide) was used to examine effects of endothelin ETA receptor blockade on renal function in spontaneously hypertensive rats. Preliminary studies were conducted to determine an effective dose of BMS-182874. Infusion of BMS-182874 (10 mumol/kg/min, i.v.) inhibited effects of exogenous endothelin-1 on glomerular filtration rate, renal blood flow, and mean arterial pressure in Sprague-Dawley rats. Administration of BMS-182874 (10 mumol/kg/min, i.v.) to anesthetized, male, spontaneously hypertensive rats decreased renal blood flow by approximately 50% (1.2 +/- 0.11 ml/min/100 g body weight) compared to vehicle (2.7 +/- 0.23). There was no effect of BMS-182874 on glomerular filtration rate (0.5 +/- 0.05 ml/min/100 g body weight; vehicle: 0.7 +/- 0.06). Mean arterial pressure decreased significantly after BMS-182874 (123 +/- 3.8 mm Hg; vehicle: 162 +/- 4.8). Urine flow and renal vascular resistance were unchanged by BMS-182874. Endothelin ETA receptor density was increased approximately 50% in spontaneously hypertensive rat kidneys compared to normotensive kidneys, with no change in equilibrium dissociation constant. Endothelin ETB receptor density and equilibrium dissociation constant were similar in the two rat strains. Plasma immunoreactive endothelin was higher in hypertensive (5.9 +/- 0.31 fmol/ml) than normotensive rats (2.8 +/- 0.15). The results suggest endothelin ETA receptors may play a role in the regulation of renal function in this model of hypertension.

Animals↗
PubMed1995

Activation of the p21 pathway of growth arrest and apoptosis by the beta 4 integrin cytoplasmic domain.

The integrin alpha 6 beta 4, a receptor for members of the laminin family of basement membrane components, contributes to the function of epithelial cells and their oncogenically transformed derivatives. In our efforts to study alpha 6 beta 4-mediated functions in more detail and to assess the contribution of the beta 4 cytoplasmic domain in such functions, we identified a rectal carcinoma cell line that lacks expression of the beta 4 integrin subunit. This cell line, termed RKO, expresses alpha 6 beta 1 but not alpha 6 beta 4, and it interacts with laminin-1 less avidly than similar cell lines that express alpha 6 beta 4. We expressed a full-length beta 4 cDNA, as well as a mutant cDNA that lacks the beta 4 cytoplasmic domain, in RKO cells and isolated stable subclones of these transfectants. In this study, we report that subclones that expressed the full-length beta 4 cDNA in association with endogenous alpha 6 exhibited partial G1 arrest and apoptosis, properties that were not evident in RKO cells transfected with either the cytoplasmic domain mutant or the expression vector alone. In an effort to define a mechanism for these observed changes in growth, we observed that expression of the alpha 6 beta 4 integrin induced expression of the p21 (WAF1; CiP1) protein, an inhibitor of cyclin-dependent kinases. These data suggest that the beta 4 integrin cytoplasmic domain is linked to a signaling pathway involved in cell cycle regulation in the beta 4 transfected RKO cells.

Antigens, CD↗
PubMed1995

Expression of kappa opioid receptors in human and monkey lymphocytes.

mRNA encoding the kappa opioid receptor gene sequence was identified and isolated from various human lymphocytic cells: CEM x174 (a hybrid of T and B origin) cells, Jurkat-T4 cells, human peripheral blood mononuclear cells (PBMC) and purified CD4+ cells. Analyzing the cDNA sequences of RNA transcripts spanning the putative second extracellular loop, which has reported dynorphin specificity, and the seventh transmembrane domain revealed a 100% and 95% homology in amino acid sequence to corresponding kappa opioid receptor sequences in human placenta and rat brain, respectively. Expression of a similar kappa opioid receptor sequence could be detected in normal monkey PBMC but not in monkey PBMC in which the CD4+/CD8+ cell ratio (or CD4+ cell number) was significantly reduced due to prolonged SIV infection. These findings suggest that human and monkey lymphocytes constitutively express kappa opioid receptor mRNA.

Amino Acid Sequence↗
PubMed1995

[A case of hepatocellular carcinoma with bone metastasis responding to oral administration of UFT].

A 63-year-old male patient with a mass in the left chest wall was referred to our hospital. An osteoclastic area was found in the mass of the left 4th rib by computed tomography; the mass was hard and little movable. There was an irregular and poorly demarcated low-density area, 5 cm in diameter, in the liver anterior superior segment. Aspiration from the mass of the chest wall indicated adenocarcinoma (class V) and forecast of metastatic lesion. The titer of serum AFP showed an extremely high level of 1,100 ng/ml. According to these findings, the patient was diagnosed as having hepatocellular carcinoma with bone metastasis and treated by the administration of oral UFT (300 mg/day). Six months later, the mass in the left chest wall was completely eliminated, the size of the hepatic lesion changed to 2.5 cm, and the titer of AFP decreased to the normal range (8.4 ng/ml). Treatment of hepatocellular carcinoma with bone metastasis is often ineffective, but this is a rare case showing the clinical effectiveness of oral administration of UFT.

Administration, Oral↗
PubMed1995

Complete two-handed laparoscopic appendectomy: report of 100 cases.

A complete two-handed technique for laparoscopic appendectomy is described. From April 1992 to July 1994, 100 patients with suspected acute appendicitis were selected to undergo this approach. This technique allows the surgeon to manipulate instruments with both hands for dissecting, transecting and removing the appendix. The appropriate placement of three cannulas in the lower abdominal midline makes this technique possible. Monopolar cautery is used to dissect the mesoappendix and to cauterize the appendicular vessels. Two ligatures are placed at the junction of the appendix with the cecum. The appendix is clamped at its base by ratchet forceps and is extracted along with the forceps immediately after transection. None of the patients selected for this procedure required conversion to open appendectomy. Postoperative complications occurred in four patients, two with umbilical wound infections and two with intra-abdominal abscesses; 12 patients had perforated appendicitis. The results of this study suggest that a complete two-handed laparoscopic appendectomy can be safely and successfully accomplished in patients with suspected acute appendicitis.

Acute Disease↗
PubMed1994

Improved myocardial function using cardiopulmonary support in resuscitation for hemorrhagic shock.

OBJECTIVES: To clarify the pathophysiologic characteristics of hemorrhagic shock and to assess methods of resuscitation. DESIGN: An animal experiment using sheep subjected to hemorrhagic shock and fibrillation to compare various resuscitation techniques. SETTING: An experimental laboratory setting meant to simulate hemorrhagic shock secondary to trauma. STUDY GROUPS: Group 1 animals (n = 6) were controls that were not subjected to shock and fibrillation. Group 2 animals (n = 6) were subjected to shock and fibrillation and were resuscitated with volume replacement. Group 3 animals (n = 6) were also subjected to shock and fibrillation but were resuscitated with epinephrine hydrochloride infusion. Group 4 animals (n = 6) were subjected to shock and fibrillation but were resuscitated with cardiopulmonary support. INTERVENTIONS: The shock was to a mean arterial pressure of 25 mm Hg for 1 hour followed by 5 minutes of fibrillation. Group 2 animals were resuscitated for 1 hour. Group 3 animals were supported for 6 hours on epinephrine after the shock period. Group 4 animals were supported for 1 hour on cardiopulmonary support, then were observed for another 5 hours. All animals were sedated and intubated, and a median sternotomy was performed. MAIN OUTCOMES MEASURED: Survival, hemodynamic function, lactate production, myocardial blood flow, and water content. RESULTS: Group 1 sheep showed no detrimental effects in any of the measured variables. Group 2 sheep could not be resuscitated. Group 3 sheep could be supported with epinephrine but had a 60% depression in left ventricular function and an ultimately high mortality rate (67%) when the infusion of epinephrine was discontinued. Group 4 sheep had a 100% survival rate and only a 20% deterioration in left ventricular function. CONCLUSIONS: Cardiopulmonary support improves survival and preserves left ventricular function compared with volume resuscitation with or without inotropic support in this model of hemorrhagic shock.

Animals↗
PubMed1993

Transaxillary endoscopic sympathectomy--a report of experience in 150 patients with palmar hyperhidrosis.

We report our 1-year experience with transaxillary endoscopic sympathectomy in 150 patients with palmar hyperhidrosis (PH). The double-puncture technique of video laparoscopy was used in a transaxillary approach to perform the sympathectomy by either electrocautery (EC; 93.3%) or electroresection (ER; 7.7%). The procedure was successfully completed in 299 operated limbs and required conversion to open surgery in 1 operated limb because of extensive pleural adhesions. The mean operative time of EC was significantly less than that of ER. In a total of 29 procedures, there were three technical complications. Most patients (92.7%) were discharged after an overnight hospital stay. On the seventh postoperative day, the cure rate was 99.3%. During the mean follow-up period of 200.1 days, there was no recurrence in 130 patients. Apparent compensatory hyperhidrosis occurred in 28 patients (21.5%). In conclusion, transaxillary endoscopic sympathectomy offers a simple and effective treatment to patients with PH, resulting in a shorter hospital stay and convalescent period.

Adolescent↗
PubMed1992

Functional alterations of swine peripheral blood mononuclear cells by methadone.

In vitro exposure of the synthetic opiate drug methadone allowed evaluation of putative immunomodulatory activities of swine peripheral blood mononuclear cells. Respiratory burst, an index of microbicidal activity, was suppressed by methadone in a dose-dependent manner following exposure for 48 h. The suppression was blocked by the opiate antagonist naloxone. Another macrophage function phagosome-lysosome fusion was impaired by exposure to methadone. A primary lymphocyte-mediated function natural killer cell activity was also affected. In contrast, the macrophage function antibody-mediated phagocytosis was not affected. Because the functions affected by methadone are critical to host defenses against pathogenic organisms, our findings suggest that opiate-mediated immunomodulation merits further study. Moreover, our studies suggest that swine may provide an ideal model for the investigation of opiate-mediated suppression of immune cell functions.

Animals↗
PubMed1992

Effect of propranolol on calcium, phosphorus, and magnesium metabolic disorders in Graves' disease.

The purpose of this study was to determine whether propranolol alone can improve mineral metabolic disorders in thyrotoxicosis. Ten Graves' disease patients and 11 normal age- and sex-matched controls participated in the study. In the untreated Graves' patients, serum levels of calcium (Ca), calcium x phosphorus product (Ca x P), urinary Ca, phosphorus (P), magnesium (Mg), and hydroxyproline (Hp) were higher than in control subjects (P less than .05), intestinal Ca absorption was lower than in control subjects (P less than .05), and Ca, P, and Mg balance were negative (P less than .05). After 40 mg propranolol four times per day (qid) for 28 days, serum triiodothyronine (T3) had decreased (P less than .05), serum reverse triiodothyronine (rT3) increased (P less than .05), serum thyroxine (T4) remained unchanged (P greater than .05), serum Ca and urine Ca and Mg decreased (P less than .05), intestinal Ca absorption increased, Ca balance was corrected, and P and Mg balance was improved (P less than .05). Our results indicate that propranolol can improve the metabolic disorders in addition to the symptomatic manifestations of Graves' disease. The mechanism responsible for the improved mineral balance is unclear, but may be related to beta-adrenergic blockade, increased membrane stability, or a decrease in the thyrotoxic state caused by the therapeutically induced decrease in serum T3.

Adolescent↗
PubMed1992

Acute and chronic morphine administration in swine.

Functional responses to acute and chronic morphine administration in domestic swine were examined and correlated with pharmacokinetic profiles. Acute effects of morphine sulfate were monitored in pigs for 24 h and the chronic actions of morphine alkaloid were monitored for 21 days. Serum morphine levels, nociception, locomotor activity, respiratory rate, body temperature, and body weight were monitored during all studies. To assess nociception in a large laboratory animal, a portable thermal stimulating device was constructed. Morphine sulfate administered IV and SC had a half-life of approximately 1 h whereas delayed-release morphine alkaloid delivered SC had a half-life of 28 h. The degree of antinociception paralleled decline in blood morphine levels for both SC- and IV-administered animals. Tolerance occurred to both antinociception as well as weight gain despite morphine levels remaining constant over the 21-day period. Morphine dependence was demonstrated by precipitation of an abstinence syndrome using naloxone. Animals in withdrawal displayed consistent signs, including wet-dog shakes, posture changes, vocalization, and salivation. Collectively, these results indicate that swine may be reliably employed as a model to study the actions of morphine and opiate-like compounds.

Analgesics↗
PubMed1992

Radiation therapy as a treatment for benign lymphoepithelial parotid cysts in patients infected with human immunodeficiency virus-1.

Patients who are infected with the human immunodeficiency virus (HIV) may develop benign lymphoepithelial cysts within the parotid gland that cause severe facial deformity. Standard treatment for this disorder has been superficial parotidectomy, repeated fine-needle aspirations or observation alone. These approaches are unsatisfactory because elective surgery in immunocompromised patients should be avoided, the cysts recur soon after aspiration, and observation alone for a treatable deforming facial process is unacceptable. Radiotherapy's proven effectiveness in treating other benign disorders of the parotid gland led us to evaluate its usefulness as a treatment for this disorder. Eight patients with parotid enlargement, who were seropositive for HIV, received 8-10 Gy to the parotids in 1 week. Five patients had complete response and three patients had partial response. All were very satisfied with the cosmetic result. Treatment-related toxicity was well tolerated and consisted of mild xerostomia and transient taste loss. In all cases, these side effects resolved within 1 month. Radiation therapy thus appears to be an effective and well-tolerated treatment for AIDS-related parotid enlargement.

Adult↗
PubMed1992

Computed tomographic finding in adenomyomatosis of the gallbladder.

We report on an uncommon case of symptomatic generalized adenomyomatosis of the gallbladder. It was initially suspected by ultrasonography and further confirmed by computed tomography (CT). A postcontrast CT scan at the level of the gallbladder body demonstrated the characteristic rosary sign. The rosary sign is formed by the enhanced proliferative mucosal epithelium with the intramural diverticula surrounded by the unenhanced hypertrophied muscle coat of the gallbladder. Similar CT scans were obtained sequentially in the caudal direction. These CT scan findings indicated generalized adenomyomatosis of the gallbladder. The patient received a cholecystectomy. The pathologic report showed specific changes of adenomyomatosis corresponding to the findings on the CT scan. Generalized adenomyomatosis of the gallbladder, therefore, can be accurately diagnosed by CT.

Adult↗
PubMed1992

Adjunctive choledochoduodenostomy to choledocholithotomy in the treatment of calculous biliary tract disease.

Between 1986 and 1991, 16 selected patients with calculous biliary tract disease (CBTD) underwent side-to-side choledochoduodenostomy (CDS) as an adjunct to either primary (10 patients) or secondary (six patients) choledocholithotomy. Patients selected for adjunctive CDS were those with common bile duct dilatation > or = 1.5 cm in size. All operations were elective procedures. The stoma of the CDS was about 3.0 cm in size, measured directly. There were no operative deaths. There were no early complications related to the CDS procedure itself, except for two (12.5%) wound infections. CDS significantly eliminates bile stasis which is indicated by a fall in both the serum levels of alkaline phosphatase (from 228 +/- 118 to 72 +/- 22 IU/L, p < 0.01) and total bilirubin (from 4.7 +/- 4.7 to 0.9 +/- 0.2 mg/dL, p < 0.01) postoperatively. Late complications (ascending cholangitis or sump syndrome) of CDS or recurrent symptoms of CBTD were not encountered during the average follow-up period of 21 +/- 18 months. From our clinical results, we suggest that adjunctive CDS to choledocholithotomy is a safe and effective procedure in the treatment of selected patients with CBTD.

Adult↗
PubMed1990

Bilateral simultaneous transaxillary sympathectomy in treatment of palmar hyperhidrosis: report of 60 cases.

Bilateral simultaneous transaxillary sympathectomies (BSTS) were established in order to achieve a one-stage transaxillary sympathectomy in the treatment of palmar hyperhidrosis. The features of the BSTS were the patient's supine operative position, parapectoral incision, and bilateral simultaneous procedures. BSTS were safely performed on 60 patients during a 5-year period. No serious complications or recurrences were encountered. The clinical results suggest that BSTS is the technique of choice for one-stage transaxillary sympathectomy in the treatment of palmar hyperhidrosis.

Adolescent↗
PubMed1989

Tumor necrosis factor-alpha is a potent ACTH secretagogue: comparison to interleukin-1 beta.

Tumor necrosis factor-alpha (TNF) and interleukin-1 beta (IL-1) are secreted by activated monocytes and other immune cells. Since IL-1 has been shown to elevate rat plasma ACTH and both of these cytokines induce similar acute-phase responses, the present studies of TNF were undertaken to characterize the ACTH response to this immune cell product. Human rTNF, administered iv at doses (100-1000 ng) which failed to affect blood pressure, food consumption or prolactin levels, resulted in significant peak elevations of rat plasma ACTH within 20 min (mean +/- SE 304 +/- 94 and 958 +/- 128 pg/ml for 100 and 1000 ng, respectively, compared to 53 +/- 16 pg/ml for vehicle). rTNF from two different sources produced similar elevations of ACTH as an equivalent amount of rIL-1. TNF failed to affect cultured anterior pituicytes, and it did not modify the response to CRF. When administered into the upper third cerebroventricle, TNF 20 ng failed to affect ACTH levels whereas IL-1 30 ng raised ACTH to 638 +/- 79 pg/ml compared to 177 +/- 24 pg/ml for vehicle (p less than .001). Furthermore, intraparenchymal injection of IL-1, directly above the median eminence, elevated ACTH to 484 +/- 93 pg/ml; again, TNF was completely ineffective. Thus, TNF-alpha and IL-1 beta are both potent ACTH secretagogues with complementary modes of action; however, the proximate target of TNF action appears to be peripheral to the CNS and pituitary whereas that of IL-1 appears to be the median eminence.

Adrenocorticotropic Hormone↗
PubMed1987

Coinduction of glucose-regulated proteins and doxorubicin resistance in Chinese hamster cells.

The glucose-regulated protein (GRP) system in mammalian cells is induced by glucose deprivation, anoxia, the calcium ionophore A23187, and 2-deoxyglucose. In Chinese hamster ovary cells the major GRPs are approximately equal to 76, 97, and 170 kDa. Removal of each of these four GRP-inducing stresses leads to the coordinate repression of GRPs and induction of the major heat shock proteins at 70 and 89 kDa. The application of each of these four GRP-inducing conditions leads to a significant induction of resistance to the drug doxorubicin. Removal of each GRP-inducing condition results in the rapid disappearance of this resistance in a manner that correlates with the repression of the GRPs. The retention of doxorubicin by GRP-induced cells does not explain the induced drug resistance. When the RIF in vitro/in vivo tumor system is probed with an antibody against the 76-kDa GRP, a significant increase in this GRP is observed in cells obtained from the central regions of tumors. Since hypoxia and/or nutrient deprivation can occur during tumor development, a GRP-induced state in the tumor may confer resistance to doxorubicin treatment.

Animals↗