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Biomedical subjects

C C Chen

Publications and source records attributed to C C Chen.

At least 289 records · Page 16Linked to original sources
PubMed1997

Apomorphine induced alteration in corneofundal potentials in depression.

1. The role of dopamine (DA) in mood regulation remains controversial. 2. Previous studies have examined DA sensitivity by measuring neuroendocrine responses following an agonist challenge. For the most part the results of such tests have failed to provide convincing evidence of a DA abnormality in affective disorders. 3. Neuroendocrine responses, however, are subject to complex regulatory influences and respond to DA systems which differ from those thought to modulate mood. 4. Recent animal and human studies suggest that light-dark adaptive electrical responses of the retinal pigment epithelium may serve as a better model of dopaminergic function. 5. The present study reports neuroendocrine and ocular results prior to, and following, an apomorphine (APO; 0.75 mg sc) challenge in 12 depressed patients and 12 normal controls. 6. Apomorphine administration increased both light and dark retinal potentials in patients whereas those of controls decreased and this group difference was significant (p < 0.002). 7. No group differences were detected in any measure at baseline, or in prolactin, or growth hormone levels after the APO challenge. 8. The results indicate that the retina may serve as a more sensitive indicator of dopamine abnormalities in depressive illness.

Adult↗
PubMed1997

A model of transient hyperalgesia in the behaving monkey induced by topical application of capsaicin.

The aim of this study was to develop a model of transient hyperalgesia in the awake monkey performing operant tasks. An adult male rhesus monkey was trained to press a lever to receive food reward for detecting a light or to escape mechanical or thermal stimuli applied in the maxillary region of the face. A small contact thermode was positioned on one side of the face and a mechanical stimulator was placed on the other side. Noxious and innocuous thermal (43, 47 and 51 degrees C) or mechanical (245, 490, 736 and 1472 mN) stimuli of 4.5-s duration were presented in a pseudo-random order. The animal was tested before, 1 h and 24 h after topical capsaicin application (0.3 ml; 0.004 M). At the site of capsaicin application, the monkey escaped more thermal and mechanical stimuli 1 h after than before capsaicin, suggestive of thermal and mechanical hyperalgesia. At 24 h post-capsaicin, mechanical escape behavior had returned to baseline, but thermal escapes were still slightly elevated. Capsaicin had no significant effect on either mechanical or thermal escape behavior for stimuli presented to the contralateral site. Seven human subjects tested with these procedures reported higher pain intensity for similar stimuli after capsaicin application, in accordance with the monkey escape behavior. It is concluded that topical application of capsaicin on the maxillary face of the awake behaving monkey produces a transient thermal and mechanical hyperalgesia. The procedure is repeatable and produces no overt signs of distress. Thus it could provide an important tool for studying neural mechanisms of hyperalgesia and for testing analgesic treatments in primates.

Acute Disease↗
PubMed1997

Molecular characterization of a defensin gene from the mosquito, Aedes aegypti.

Insect immune proteins, defensins, are inducible anti-Gram-positive bacterial peptides. We report here the identification of two defensin genes from the mosquito, Aedes aegypti, which encode a large 541 bp transcript (AaDef Ala) and a small 473 bp transcript (AaDef Asm). The cDNA corresponding to AaDef Ala was cloned, sequenced, and compared with the previously reported AaDef Asm cDNA. The AaDef Ala gene was isolated through genomic library screening and characterized. It putative regulatory region contains a 64 bp intron, a TATA box and a putative arthropod initiator. Two 150 bp long direct and several palindromic repeats are present in this sequence. Similar to other insect immune peptide genes, the AaDef Ala gene contains numerous putative regulatory motifs with impressive similarity to elements of vertebrate acute phase response protein genes.

Aedes↗
PubMed1997

Human Taenia eggs develop into cysticerci in scid mice.

The intermediate hosts for Taenia saginata and T. solium are cattle and pigs (and humans for the latter), respectively. In vitro-hatched (but not activated) oncospheres of both Asian Taenia (T. saginata asiatica, a new subspecies of T. saginata or T. asiatica, a new species) and T. solium injected subcutaneously into the backs of mice with severe combined immunodeficiency (scid) developed into fully matured cysticerci. Five-month-old metacestodes of Asian Taenia had no hooklets and were bigger in size than those previously reported and similar to those of T. saginata. Their morphology suggested that the cysticerci were more advanced than those in the intermediate host animals. It is suggested that scid mice are valuable experimental animal models for studying human taeniid cestode infections.

Animals↗
PubMed1997

Effects of inhibitors of serine protease, phenoloxidase and dopa decarboxylase on the melanization of Dirofilaria immitis microfilariae with Armigeres subalbatus haemolymph in vitro.

The melanization of Dirofilaria immitis microfilariae in Armigeres subalbatus haemolymph in vitro is a two-step process. Firstly, the microfilariae are encased in a transparent capsule, then the capsule material is melanized later. Benzamadine HC1 and p-amidinophenylmethanesulfonyl fluoride, both serine protease inhibitors, inhibited the deposition of the transparent capsule material and melanization. Diethyldithiocarbamate, a phenoloxidase inhibitor, did not prevent the deposition of the transparent capsule material but it did inhibit melanization. m-Hydroxybenzylhydrazine, a dopa decarboxylase inhibitor, had no inhibitory action on the deposition of the transparent capsule material. However, the time for the transparent capsule to become melanized was delayed due to the presence of m-hydroxybenzylhydrazine in the test system. Immmunocytochemical localization showed that propheoloxidase and/or phenoloxidase was present in the transparent capsule material. These results suggest (1) that prophenoloxidase cascade is essential in the melanization of microfilariae in mosquitoes and its putative activation behaviour is similar to that of other insects and (2) that the deposition of transparent capsule material is the result of the activation of prophenoloxidase by serine proteases and the melanization of the transparent capsule material is due to the presence of active phenoloxidase in capsule.

Animals↗
PubMed1997

Selective cytotoxicity of ginkgetin from Selaginella moellendorffii.

Bioassay-directed fractionation of an ethanolic extract of Selaginella moellendorffii has led to the isolation of a known biflavone, ginkgetin (1). A dose-dependent inhibition was observed with 1 on the growth of OVCAR-3 (human ovarian adenocarcinoma) cells with 50% inhibition occurring at 1.8 micrograms/mL. Nonbioactive fractions yielded four additional known biflavones, amentoflavone 7,4',7",4"'-tetramethyl ether, kayaflavone, podocarpusflavone A, and amentoflavone.

Animals↗
PubMed1997

Two tandemly repeated telomere-associated sequences in Nicotiana plumbaginifolia.

Two tandemly repeated telomere-associated sequences, NP3R and NP4R, have been isolated from Nicotiana plumbaginifolia. The length of a repeating unit for NP3R and NP4R is 165 and 180 nucleotides respectively. The abundance of NP3R, NP4R and telomeric repeats is, respectively, 8.4 x 10(4), 6 x 10(3) and 1.5 x 10(6) copies per haploid genome of N. plumbaginifolia. Fluorescence in situ hybridization revealed that NP3R is located at the ends and/or in interstitial regions of all 10 chromosomes and NP4R on the terminal regions of three chromosomes in the haploid genome of N. plumbaginifolia. Sequence homology search revealed that not only are NP3R and NP4R homologous to HRS60 and GRS, respectively, two tandem repeats isolated from N. tabacum, but that NP3R and NP4R are also related to each other, suggesting that they originated from a common ancestral sequence. The role of these repeated sequences in chromosome healing is discussed based on the observation that two to three copies of a telomere-similar sequence were present in each repeating unit of NP3R and NP4R.

Base Sequence↗
PubMed1997

Mature teratoma arising from an intra-abdominal undescended testis presenting as a fetal abdominal mass.

Teratoma of the intra-abdominal testis is a rare finding in infants. We describe the case of a full-term newborn treated for a calcified abdominal mass which was observed unexpectedly on prenatal sonography. An undescended right testis was also noted. During laparotomy, a twisted retroperitoneal tumor was found just above the right deep inguinal ring. Histological analysis revealed a mature teratoma of the intra-abdominal right testis. The tumor was removed and there was no recurrence at follow-up 1 year later. A teratoma should be considered in cases of fetal abdominal mass, especially when the testes cannot be detected in the scrotum by the 8th month. Prenatal sonographic diagnosis might be possible.

Adult↗
PubMed1997

P2Y receptor linked to phospholipase C: stimulation of neuro 2A cells by UTP and ATP and possible regulation by protein kinase C subtype epsilon.

Incubation of Neuro 2A mouse neuroblastoma cells with UTP and UDP results in a concentration-dependent increase in the accumulation of inositol phosphates with equal potency and maximal effect; ATP, ADP, and 2-methylthioadenosine 5'-triphosphate were much less potent, indicating the expression of P2Y receptor in these cells. The effects of UTP and ATP were not affected by pretreatment of cells with pertussis toxin, indicating that the P2Y receptor in Neuro 2A cells is coupled to pertussis toxin-insensitive Gq protein. Short-term (10 min) treatment of cells with 1 microM 12-O-tetradecanoylphorbol 13-acetate (TPA) resulted in the inhibition of the UTP and ATP effects; this inhibitory effect was gradually attenuated with increased length of TPA treatment (1.5-6 h) and was not seen after long-term (24 h) treatment. Western blot analysis showed the expression of protein kinase C (PKC) alpha, epsilon, theta, and zeta in Neuro 2A cells. Translocation of PKC alpha, epsilon, and theta from the cytosol to the membrane was seen after 10 min or 1.5 h of treatment with TPA. However, partial and complete down-regulation of both membrane PKC alpha and theta were seen after 3 and 6 h of treatment, respectively. In contrast, the TPA-induced translocation of PKC epsilon was maintained after 3-6 h of treatment, and almost complete down-regulation occurred only after a 24-h treatment. The observed TPA-induced inhibition of UTP- or ATP-stimulated phosphoinositide hydrolysis, therefore, correlated well with the extent of translocation of PKC epsilon. Phosphoinositide hydrolysis induced by AlF4-, but not Ca2+ ionophores, was inhibited by a 10-min treatment with TPA. This was not seen after a 24-h treatment, indicating that the site of action of PKC epsilon in the P2Y receptor/Gq protein/phospholipase C beta pathway might be the Gq protein. This is the first study to show the existence of the P2Y receptor in Neuro 2A cells and the possible involvement of neuronal PKC epsilon in the regulation of the receptor-mediated phosphoinositide turnover.

Adenosine Triphosphate↗
PubMed1997

Value of somatostatin receptor scintigraphy: a prospective study in gastrinoma of its effect on clinical management.

BACKGROUND & AIMS: Recently [111In-DTPA-D-Phe1]-octreotide was approved for somatostatin receptor scintigraphy (SRS) of gastroenteropancreatic tumors. SRS and other tumor localization methods can be time consuming, expensive, and involve patient inconvenience. The role of SRS in comparison to other tumor localization modalities remains undefined because the relative effects of these methods on management have not been studied. The aim of this study was to determine whether SRS alters clinical management in Zollinger-Ellison syndrome. METHODS: One hundred twenty-two consecutive patients were studied prospectively. Each patient was assigned to one of five different clinical categories. Conventional imaging studies (ultrasonography, computerized tomography, magnetic resonance image, angiography, and bone scan) were performed, and the management was proposed. SRS was then performed. Clinical management was reassessed, and whether SRS altered management was determined based on six criteria. RESULTS: SRS was superior to any single imaging study. SRS altered management in 47% overall and in 22%-60% of patients in the five different clinical categories. Primary tumor localization and clarification of equivocal localization results from conventional studies were the principal reasons for altering management. SRS was equally useful in patients with or without metastatic liver disease. CONCLUSIONS: Because of the ability of SRS to alter clinical management combined with its superior sensitivity, high specificity, simplicity, and cost-effectiveness, SRS should be the initial imaging modality for patients with gastrinomas.

Adult↗
PubMed1997

Isometric muscle strength of Chinese young males in Taiwan.

This paper represents the results of an anthropometric measurement of the isometric muscle strength of Chinese young males in Taiwan aged from 16 to 20 years. The study uses a sample of 120 male students and measures four types of muscle strength: (1) right arm strength in exerting pull, push, adduction, abduction, lift, and press directions with five elbow angles (60, 90, 120, 150 and 180 degrees) in seated posture; (2) grip strength of both hands; (3) backlift strength: and (4) chest expanding strength. The obtained data are analysed and listed. Comparisons are made between the results of this study and those from domestic and foreign studies available in the literature. In general, their pattern is similar, but values obtained in this study are relatively smaller than those obtained in western countries.

Adolescent↗
PubMed1997

Reversed arterial flow in free flap surgery for leg reconstruction.

A lower leg open fracture with an accompanying extensive soft-tissue defect may require free flap transfer to resurface the wound. In open-leg fracture injuries the major arteries are frequently damaged during the injurious event. When the antegrade arterial blood flow is not available for arterial inflow to the free flap, end-to-side arterial anastomoses or a venous graft from a proximal healthy artery is an appropriate solution. Reversed arterial flow is another technique that may be used to provide arterial inflow to the free flap. We report 5 patients with open tibial fracture injuries that were successfully covered using latissimus dorsi muscle free flaps with reverse arterial inflow and either antegrade venous outflow (4 patients) or retrograde outflow (1 patient). This technique is indicated when (1) the defect is not located at the site adjacent to the residual antegrade artery, (2) a long vein graft might pass through severely scarred soft tissue, or (3) after failure in end-to-side anastomosis with accompanying insufficient antegrade proximal arterial flow but good distal arterial reflux.

Adolescent↗
PubMed1997

Postoperative MRI of anorectal malformation.

Twenty-five patients who had pull-through rectum (PTR) surgery, some of whom suffered from fecal incontinence, soiling or constipation were studied by magnetic resonance imaging (MRI) postoperatively. MRI demonstrated 14 patients with proper placement of the PTR between the puborectal muscle and external sphincter muscle; four patients with improper placement of the PTR outside the puborectal muscle and external sphincter muscle (one with excess perirectal fat); one patient with disruption of the puborectal muscle and external sphincter muscle; three with hypoplasia of the puborectal muscle and external sphincter muscle; three with asymmetric placement of PTR in the levator ani (one with excess perirectal fat). MRI also depicted seven patients with spine anomalies; five with tethered cord; and 10 with genitourinary tract anomalies. The patients with correct location of PTR all had good fecal continence except three patients (two with soiling and one with constipation) who had tethered cord and ganglion cell dysfunction at the PTR. The patients with improper placement of PTR or poorly developed pelvic muscles all had fecal incontinence. Our study emphasizes that MRI can depict the causes of postoperative incontinence, detect anomalies and help to plan further surgery.

Adolescent↗
PubMed1997

Morphine augmentation increases gallbladder visualization in patients pretreated with cholecystokinin.

UNLABELLED: The purpose of this study was to determine if a combination of cholecystokinin (CCK) pretreatment followed by morphine augmentation improved the detection of cystic duct patency compared with CCK pretreatment only. METHODS: One hundred fifty-five patients with suspected acute cholecystitis had scintigraphy performed with 185-481 MBq (5-13 mCi) 99mTc-mebrofenin adjusted to the patients' total bilirubin levels. All patients were pretreated with 0.02 microgram/kg sincalide injected intravenously over 3-5 min. Sequential imaging was performed until gallbladder activity was identified or up to 90 min postinjection of mebrofenin. If no gallbladder was identified, a second dose of mebrofenin was given as necessary to have tracer in the biliary system. Then, 0.04 mg/kg intravenous morphine sulfate was administered, followed by imaging for up to 30 min or until gallbladder visualization. RESULTS: Twenty-eight percent (43/155) of the patients pretreated with CCK had nonvisualization of the gallbladder at 90 min postinjection of radiotracer. After intravenous morphine, the gallbladder was identified in 42% (18/43) of these patients (p = 0.0001). CONCLUSION: Hepatobiliary imaging with CCK pretreatment and imaging for 90 min was insufficient to identify all patent cystic ducts. Morphine augmentation significantly increased the frequency of gallbladder visualization in patients pretreated with CCK.

Acute Disease↗
PubMed1997

The binge eating and emotional change in a patient with postinfectious encephalomyelitis.

Postinfectious encephalomyelitis is a kind of demyelinating disease with pathological characteristics and a monophasic clinical course. Herein, we describe a patient who had the symptoms of binge eating, fatigue, memory impairment, hypotalkativeness, hypoactivity, lethargy, incoherent speech, dysphoric mood, and episodic disorientation. Only elevation of CSF protein was noted upon initial admission; however, blurred vision of the eyes developed progressively after discharge. A magnetic resonance image (MRI) scanning of the brain demonstrated scattered lesions of low signal intensity on T1-weighted images and high areas on T2-weighted images in the left thalamus, bilateral hypothalamus and midbrain. The findings of MRI image, CSF, and clinical course all suggested postinfectious encephalomyelitis. After a treatment of prednisolone, a follow-up MRI revealed evidence of improvement, and the binge eating also improved.

Adult↗
PubMed1997

Periodontal manifestations and treatment of Sturge-Weber syndrome--report of two cases.

Encephalotrigeminal angiomatosis (Sturge-Weber syndrome) is a rather uncommon congenital condition characterized by the combination of venous angioma of the leptomeninges over the cerebral cortex with ipsilateral angiomatous lesions of the face and sometimes, the skull, jaws and oral soft tissues. Two patients came to the Kaohsiung Medical College Hospital's dental clinic with complaints of localized gingival enlargement or tumor-like swelling. Based on the presence of facial nevus flammeus, examinations of angiography, radiological evidence of calcific densities, and ipsilaterally intraoral vascular hyperplasia in the lip, cheek and gingiva, encephalotrigeminal angiomatosis was diagnosed. Dental management included plaque control instructions, scaling, root planing and periodontal surgery. Recurrence of gingival enlargement in both cases was noted, so periodontal surgery was performed a second time. Close follow up and complete plaque control have kept the periodontal condition fairly well under control in these two cases. We introduce the oral manifestations and the experience of treatments in these two cases.

Adolescent↗
PubMed1997

Collagen synthesis in idiopathic and dilantin-induced gingival fibromatosis.

Gingival fibromatosis is an uncommon but benign oral disease which causes progressive and non-hemorrhagic enlargement of the gingiva. There are two types of gingival fibromatosis: idiopathic gingival fibromatosis (GF), which is of unknown cause and may be associated with hereditary factors, and drug-induced gingival fibromatosis which is caused primarily by phenytoin intake. In cases of gingival fibromatosis, either the teeth are delayed in emergence or most of the crowns are embedded in the soft tissue even after full eruption. The objective of this study was to examine the basis of excess collagen formation in the two types of gingival fibromatosis in four patients admitted to the dental clinic at Kaohsiung Medical College Hospital, Kaohsiung, Taiwan. There were two male patients, aged ten (Case 1) and sixteen (Case 2), with idiopathic gingival fibromatosis and hypertrichosis, and two female patients, aged sixteen (Case 3) and eleven (Case 4), with Dilantin-induced gingival hyperplasia (DGH). Cultures of gingival fibroblast were established either from clinically excised hyperplastic tissues or from pre-orthodontic surgical normal gingiva. The synthesis of collagen and levels of prolyl hydroxylase, a key enzyme in collagen synthesis, were examined in the healthy and affected fibroblasts. Our studies showed that after two days in culture, fibroblasts from all four patients multiplied faster than healthy gingival fibroblasts, though the amount of DNA and protein per cell remained unchanged. In addition, all cultures (except Case 1) had a 2- to 3- fold increase of prolyl hydroxylase activity over that of the controls. As in the cases of prolyl hydroxylase activity, Case 1 did not show any change in collagen synthesis when compared to the control. However, Cases 2, 3, and 4 showed appreciable collagen increases in the cell and medium: 61% and 60% for Case 2; 16% and 36% for Case 3; and 21% and 80.7% for Case 4 respectively.

Adolescent↗