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Biomedical subjects

C C Chen

Publications and source records attributed to C C Chen.

At least 253 records · Page 14Linked to original sources
PubMed1998

Long latency responses in pure sensory stroke due to thalamic infarction.

OBJECTIVES: Our study was designed to clarify the role of the thalamus in the generation of the electrically elicited long-latency reflexes (LLR) in voluntarily activated hand muscles. MATERIALS AND METHODS: EMG responses of the thenar muscles were evoked by electrical stimulation of the median nerve at the wrist at motor threshold intensity in 10 patients with acute pure sensory stroke due to thalamic infarction. Concomitant recording of somatosensory evoked potentials (SEPs) was performed. The subjects were asked to steadily abduct the thumb at 20-30% of maximal force against a force transducer. Rectified and averaged EMG activities were recorded. RESULTS: The LLR II was missing completely or significantly attenuated in the majority of the patients (9 of 10), of whom 3 also had delayed latency. Abnormal SEPs were documented in 7 patients (7 of 10). In the follow-up, 5 patients had partial reversal of LLR II. LLR II was still pathological in 1 fully recovered patient. CONCLUSION: Our results further confirm the transcortical generation of LLR II and imply that a thalamic relay is present in the afferent limb of the LLR.

Adult↗
PubMed1998

Gingival crevicular fluid lactoferrin levels in adult periodontitis patients.

The present study was designed to determine in a cross-sectional study whether there was any relationship between the levels of lactoferrin in gingival crevicular fluid and clinical periodontal parameters. Crevicular fluid was collected from individual sites using standardized filter paper strips (clinically healthy sites, N = 23; periodontitis sites, n = 66) and evaluated for lactoferrin by enzyme-linked immunosorbent assay. The data showed that: (1) the total amounts of lactoferrin were 0.003-0.021 ng (30 second sample) (average 0.009 +/- 0.005 ng) in a clinically healthy periodontium group and 0.016-3.847 ng (30 second sample) (average 0.575 +/- 0.069 ng) in adult periodontitis patients (statistically significantly higher in adult periodontitis patients); and (2) the total amounts of lactoferrin were significantly correlated with clinical parameters, especially a strong positive correlation with gingival crevicular fluid volume (r = 0.85, p < 0.01) and with probing depth (r = 0.71, p < 0.01). These results indicated that quantification of lactoferrin in gingival crevicular fluid may be a more sensitive indicator of periodontal pathology than traditional clinical indices.

Adult↗
PubMed1998

Possible involvement of protein kinase c inhibition in the reduction of phorbol ester-induced neutrophil aggregation by magnolol in the rat.

The influence of the plant product magnolol on neutrophil aggregation has been investigated in the rat. Magnolol inhibited phorbol 12-myristate 13-acetate (PMA)-activated rat neutrophil aggregation in a concentration-dependent manner with an IC50 (concentration resulting in 50% inhibition) of 24.2 +/- 1.7 microM. Magnolol suppressed the enzyme activity of neutrophil cytosolic and rat brain protein kinase C (PKC) over the same range of concentrations at which it inhibited the aggregation. Magnolol did not affect PMA-induced cytosolic PKC-alpha and -delta membrane translocation or trypsin-treated rat-brain PKC activity, but attenuated [3H]phorbol 12,13-dibutyrate binding to neutrophil cytosolic PKC. These results suggest that the inhibition of PMA-induced rat neutrophil aggregation by magnolol is probably attributable, at least in part, to the direct suppression of PKC activity through blockade of the regulatory region of PKC.

Animals↗
PubMed1998

Partial characterization of the Streptomyces lividans xlnB promoter and its use for expression of a thermostable xylanase from Thermotoga maritima.

Xylanase activity assays were used to screen a Streptomyces coelicolor genomic library in Escherichia coli, and a xylanase gene that is 99% identical to the xylanase B gene (xlnB) of S. lividans (GenBank accession no. M64552) was identified. The promoter region of this gene was identified by using a transcriptional fusion between the upstream region of the S. coelicolor xlnB gene and the xylE reporter gene. Transcription from the xlnB promoter was found to be induced by xylan and repressed by glucose. A single apparent transcription start site was identified by both primer extension analysis and in vitro run off transcription assays. Analysis of deletions of the promoter identified a region required for glucose repression. By using the transcriptional and protein localization signals of the Streptomyces xlnB gene, an in-frame translational fusion between the end of the xlnB signal sequence and the ATG of the Thermotoga maritima xynA gene was constructed. The xynA gene encodes a thermostable xylanase that has been demonstrated to be useful in the bleaching of Kraft pulp. The xlnB-xynA gene fusion was expressed in Streptomyces, and the activity of the protein produced was thermostable and was localized to the supernatant fraction of harvested cells.

Amino Acid Sequence↗
PubMed1998

Bone metastases in patients with gastrinomas: a prospective study of bone scanning, somatostatin receptor scanning, and magnetic resonance image in their detection, frequency, location, and effect of their detection on management.

PURPOSE: To determine whether bone scan, magnetic resonance imaging (MRI), or somatostatin receptor scintigraphy (SRS) is best for identifying bone metastases in patients with gastrinomas, as well as their frequency and location, whether their detection affects management, and what patient subgroups should be examined. MATERIALS AND METHODS: One hundred fifteen patients with gastrinoma were prospectively studied. Patients were examined yearly and those with liver metastases were reexamined every 3 months. Based on clinical history, histology, growth pattern, and development of new bone lesions, possible bone metastases were classified as to whether they were or were not bone metastases. Imaging results were correlated at different times in the disease course and with disease extent. RESULTS: Bone scan was positive in 52 patients, MRI in seven, and SRS in six. Eight patients (7%) were determined to have bone metastases and MRI was correctly positive in seven, SRS in six, and bone scan in five. SRS or MRI was positive in all patients with bone metastases. Bone scan had significantly lower specificity and sensitivity, and a higher rate (P < .02) of false-negative results than MRI or SRS. Bone metastases occurred in 31% of patients with liver metastases and 0% with only lymph node metastases. The initial bone metastases were in the spine or sacrum (75%) followed in descending order by the pelvis or sacroiliac joints (38%), scapula or shoulder, and ribs. In all cases, detection of bone metastases changed the management. CONCLUSION: SRS and MRI, because of high sensitivity and specificity, are recommended over bone scanning to screen for bone metastases in patients with gastrinomas. However, because bone metastases can occur initially outside the axial skeleton, SRS is the recommended initial localization method of choice. Bone metastases occur in 7% of all patients and 31% of patients with liver metastases, only occur in patients with liver metastases, are usually in the axial skeleton initially, and their detection changes management in all cases. Patients with pancreatic endocrine tumors with liver metastases should undergo SRS every 6 months to 1 year to detect bone metastases.

Adolescent↗
PubMed1998

Visualization of fibrous dysplasia during somatostatin receptor scintigraphy.

Somatostatin receptor scintigraphy was performed on a patient with McCune-Albright syndrome and acromegaly. No evidence of pituitary disease was found, but uptake of (111)In-pentetreotide was noted in areas of fibrous dysplasia. This uptake was not changed after 6 mo of octreotide therapy. The patient's bone disease also remained stable. The possible implications of these findings are discussed.

Bone and Bones↗
PubMed1998

Severe colonic complications in acute pancreatitis.

BACKGROUND: Colonic complications in patients with acute pancreatitis may be very severe and have rarely been analyzed in Chinese patients. METHODS: We retrospectively evaluated 1,637 patients with acute pancreatitis who were admitted to the Veterans General Hospital-Taipei from January 1986 to December 1995 in order to identify those with severe colonic complications. The clinical, radiologic and pathologic features and surgical findings in these patients are reviewed. RESULTS: Eight of 1,637 patients with acute pancreatitis had severe colonic complications. Six of them were diagnosed between two and eight weeks after the onset of clinical pancreatitis. All had a Ranson's score of at least 3. Four patients, including one with hematochezia, had a strong positive reaction for occult blood in stool specimens. Computed tomography (CT) revealed necrotizing pancreatitis and colonic wall swelling in all eight patients. Colonic involvement was discovered by CT in two patients prior to surgery, one with colocutancous fistula and the other with colonic perforation. The other six patients were found to have colonic involvement incidentally at the time of laparotomy. All of the colonic involvements were located near the splenic flexure. In addition to necrosectomy, three patients underwent segmental hemicolectomy and the remaining five patients had simple closure of the perforation. Diverting loop ileostomy or colostomy was also carried out in all patients. Three patients (34%) died of overwhelming sepsis superimposed on the subsequent multiple organ failure between 44 and 122 days after the onset of pancreatitis. CONCLUSIONS: Severe colonic complications of acute pancreatitis are rare. Although preoperative diagnosis is difficult, CT may be helpful to make an early diagnosis. These complications should be suspected in patients with severe acute pancreatitis when acute lower gastrointestinal hemorrhage or positive stool occult blood is found two to eight weeks after the onset of pancreatitis or when CT reveals necrotizing pancreatitis and colonic wall swelling; this will allow early surgical intervention.

Acute Disease↗
PubMed1998

Factors affecting postoperative fecal soiling in Hirschsprung's disease.

We retrospectively assessed the factors that may contribute to fecal soiling after surgery for Hirschsprung's disease. Fifty-eight patients underwent surgery for Hirschsprung's disease and returned for follow up. The patients were divided into two groups based on the presence or absence of fecal soiling. The postoperative period, level of bowel pulled through, stool frequency, stool character, presence or absence of anorectal surgical complications, and manometric findings of the two groups were compared. Forty-three patients (40 boys, 3 girls, mean age 9.5 yr) had soiling and 15 (10 boys, 5 girls, mean age 10.2 yr) did not. Patients with soiling had significantly higher rates of anorectal surgical complications (60% vs 7%), abnormal stool character (75% vs 7%), stool frequency greater than three times per day (63% vs 20%), absence of rectoanal inhibitory reflex (33% vs 2%), and narrow anorectal pressure gradient (60% vs 13%) than those without. The results of manometric study suggested that a damaged internal sphincter or irritable neorectum might have contributed to fecal soiling. In conclusion, although anorectal surgical complications might result in both irritable neorectum and damaged internal sphincter, their effect on the neorectum (significantly increased rate of high resting rectal pressure) seemed to outweigh that on the internal sphincter. A competent anal sphincter and a less irritable neorectum after operation may therefore lower the likelihood of fecal soiling.

Adolescent↗
PubMed1998

The predictors of long-term care service utilization among older Americans.

Long-term care for the elderly has recently become an area of great interest for practicing social workers because of the increasing number of aged persons and the important role of government in financing and regulating their care. Therefore, the purpose of this study was to provide a set of estimates on patterns in long-term care service use among older Americans over an eight-year period. This study applied multinomial logistic regression to analyzing the data from the National Long-Term Care Survey of 1982-1989 (NLTCS). The results of this study showed a number of differences from the results with cross-sectional studies. Of the 6,393 sample persons, more than half (56.5%) died over the eight years from 1982 to 1989. The rate of entering nursing homes (12.6%) was low. The rate of using community-based care services was fairly low. About 10.4 percent of the sample received care from helping professional personnel or paid helpers. As expected, the number receiving care from kin and other informal support was high. Long-term care services in the United States were distributed very unequally among various social groups. The indicator of need was not the only determinant of service utilization. Other variables such as number of household members, race, age and education were also important for service utilization. The predictors of deceased versus informal help were need, age, number of household member, gender and marital status. The predictors of nursing home care versus informal help were need, age, number of household members, education, attitude toward nursing home and race. The predictors of community-based help care versus informal help were need, number of household members, and education.

Aged↗
PubMed1998

A SPECT study of patients with gait apraxia without evidence of frontal lobe dysfunction.

BACKGROUND: The pathogenesis of gait apraxia (GA) is unknown. Even though imaging studies provide excellent assessment of brain morphology, there is still a lack of congruous results. Single photon emission computed tomography (SPECT) using Tc-99m hexamethylpropyleneamine oxime (HMPAO) may show alterations in regional cerebral blood flow (rCBF) and provide indirect information about brain metabolism. METHODS: We conducted a SPECT study of GA patients and evaluated the related cortical function. rCBF was assessed in 16 GA patients (15 male, one female; age range 65-79 years, mean 70.5 years) by SPECT using HMPAO. Mean HMPAO cortical or basal ganglia/cerebellum activity ratios were calculated. The regions of interest included the frontal lobe, parietal lobe and basal ganglia. A battery of GA tests and magnetic resonance imaging (MRI) of the brain were also performed in these 16 patients. RESULTS: Nine of the patients had equilibrium disorder, and all 16 patients had locomotion disorder. The MRI findings were lacunar infarct (16/16 in basal ganglia, or 6/16 in thalamus), leukoaraiosis (4/16), enlarged ventricle (3/16), frontal lesion (3/16) and parietal lesion (1/16). Lower rCBF was noted in the frontal lobe (3/16), occipital lobe (1/16, thalamus (7/16) and basal ganglia (9/16). Though SPECT showed decreased rCBF in nine patients (9/16), mean cortical and basal ganglia regional uptake ratios in the patient group were not significantly different from values in the control group (cortical p = 0.0613; basal ganglia p = 0.0576, by Student's t-test). CONCLUSIONS: Though only a small number of patients were studied, it was clear that brain SPECT and MRI did not show any significant abnormalities in the frontal or parietal lobes of patients with GA. Thus, the pathogenesis of GA and its related anatomic lesion should be further investigated.

Aged↗
PubMed1998

[Interleukin-6 production by human gingival fibroblasts following stimulation with Actinobacillus actinomycetemcomitans].

Actinobacillus actinomycetemcomitans(Aa), elaborating a multiplicity of virulence factor and tissue-damaging products, is considered an etiological agent in periodontal disease. Serotype b is the most frequently isolated serotype in localized juvenile periodontitis patients, suggesting a particularly high periodontopathic potential for serotype b strains. Interleukin-6(IL-6) plays an important role in the mediation of inflammatory and immune responses as well as in the osteoclastic bone resorption. However, there is little information regarding the effect of the different serotypes of Aa on IL-6 production by human gingival fibroblasts (HGF). Therefore, the purpose of this study was to compare the ability of the three serotypes (a, b, and c) of Aa sonicates to induce the production of IL-6 by HGF. In fibroblast cultures, confluent monolayers of HGF were incubated with sonic extracts of Aa-511 (serotype a), Aa-Y4 (serotype b), and Aa-652 (serotype c) at various concentrations for 48 h at 37 degrees C in 5% CO2 and air. At the end of the culture period, supernatants were collected and analysed for IL-6 content by using EIA and bioassay. In order to compare the effects of non-lipopolysaccharide (LPS) activation of Aa sonicates on IL-6 production by HGF, we added polymyxin B in cultures with Aa sonicates to bind LPS. The results were summarized as follows. (1) All three serotypes of Aa sonicates had similar dose-dependent stimulant effects on IL-6 production by HGF, and the biological activities of IL-6 correlated with their immunoreactivities. (2) The maximum releases of IL-6 by HGF were achieved at concentrations of 10 to 100 micrograms protein/mL of Aa sonicates, and the ability of Aa-Y4 to induce the release of IL-6 was higher than that of Aa-511 and Aa-652 at these concentrations. (3) Polymyxin B (50 micrograms/mL) effectively decreased the amounts of IL-6 produced by stimulation of the HGF with 10 micrograms protein/mL of Aa sonicates. However, the polymyxin B-treated Aa-Y4 sonicate showed a higher ability to induce the release of IL-6 than the other two strains. These results indicate that Aa-Y4 (serotype b) has a higher potency to induce HGF secretion of IL-6; thus contributing to a comparatively stronger efficacy to the destruction of periodontal tissue in periodontitis.

Adult↗
PubMed1998

Self-reported flushing and genotypes of ALDH2, ADH2, and ADH3 among Taiwanese Han.

The aims of this study are to investigate whether self-reported facial flushing postalcohol consumption (PAC) among subjects with ALDH2*1/*1 can be attributed to ADH2 or ADH3 and whether the prediction of ALDH2 genotype can be improved by examining the combination of flushing and other accompanying reactions of PAC sensitivity. Fifty-eight subjects of Han ancestry in Taiwan were interviewed for alcohol-sensitivity reactions and their blood samples were genotyped for ALDH2, ADH2, and ADH3. For subjects with ALDH2*1/*1 (n = 46), 70% reported to have no flushing PAC and 30% reported flushing PAC. When subjects with ALDH2*1/*1 had ADH2*1/*1 (n = 11), all reported to have no flushing; otherwise, 35% (for ADH2*1/*2, n = 17) and 44% (for ADH2*2/*2, n = 18) reported flushing. For subjects with ALDH2*1/*1 and at least one ADH2*2 allele, the genotype of ADH3 was not associated with self-reported flushing. PAC flushers with ALDH2*1/*1 (50%) were more likely to report nausea than those with ALDH2*1/*2 (8%). The probability of ALDH2*1/*1 given flushing reported was 0.29, while the probability of ALDH2*1/*1 given both flushing and nausea reported was 0.71. The results indicate that self-reported flushing is determined by both ALDH2 and ADH2 and that prediction of ALDH2 genotype on the basis of self-reported flushing and nausea can help identify subjects at increased risk for alcoholism.

Adult↗
PubMed1998

A surface measure for probabilistic structural computations.

Computing three-dimensional structures from sparse experimental constraints requires method for combining heterogeneous sources of information, such as distances, angles, and measures of total volume, shape, and surface. For some types of information, such as distances between atoms, numerous methods are available for computing structures that satisfy the provided constraints. It is more difficult, however, to use information about the degree to which an atom is on the surface or buried as a useful constraint during structure computations. Surface measures have been used as accept/reject criteria for previously computed structures, but this is not an efficient strategy. In this paper, we investigate the efficacy of applying a surface measure in the computation of molecular structure, using a method of probabilistic least square computations which facilitates the introduction of multiple, noisy, heterogeneous data sources. For this purpose, we introduce a simple purely geometrical measure of surface proximity called maximal conic view (MCV). MCV is efficiently computable and differentiable, and is hence well suited to driving a structural optimization method based, in part, on surface data. As an initial validation, we show that MCV correlates well with known measures for total exposed surface area. We use this measure in our experiments to show that information about surface proximity (derived from theory or experiment, for example) can be added to a set of distance measurements to increase significantly the quality of the computed structure. In particular, when 30 to 50 percent of all possible short-range distances are provided, the addition of surface information improves the quality of the computed structure (as measured by RMS fit) by as much as 80 percent. Our results demonstrate that knowledge of which atoms are on the surface and which are buried can be used as a powerful constraint in estimating molecular structure.

Animals↗
PubMed1998

Cutaneous sinus tracts of dental origin: clinical review of 37 cases.

Cutaneous sinus tracts in the face and neck region are often dental in origin. The purpose of this study was to characterize the clinical features and treatment of 37 consecutive cases of odontogenic cutaneous sinus tracts, collected and reviewed in a 15-year period. More than half of the patients (21 cases, 57%) were referred from medical doctors, particularly plastic surgeons and dermatologists. The sinus tracts were associated with caries (26 cases), incomplete endodontic treatment (7), crown fracture (2), vertical root fracture (1) and impacted mandibular third molar (1). They occurred most often in adolescents and adults (30 cases, 81%). The most common causative teeth were mandibular teeth (34 teeth, 85%). The chin, submental, and cheek areas were the most common sites of sinus tracts (30 cases, 81%). The majority of causative teeth (32 teeth, 80%) were treated endodontically. All fistulas healed uneventfully after proper dental treatment, without cosmetic surgery. In 63% (20 cases) of the recorded cases, complete resolution occurred within 8 weeks. Half of the patients had had fistulas for more than 6 months before receiving dental treatment, demonstrating that delays in proper diagnosis and treatment were common. As most patients suffered from unnecessary medication or surgery due to the delay of dental treatment, early dental consultation and treatment is important. Conventional endodontic treatment should be the treatment of choice if the tooth is salvageable. The increasing incidence of incomplete endodontic treatment in association with the occurrence of sinus tracts indicates that standardized endodontic therapy should be emphasized for prevention.

Adolescent↗
PubMed1998

Prevention of coughing induced by endotracheal tube during emergence from general anesthesia--a comparison between three different regimens of lidocaine filled in the endotracheal tube cuff.

BACKGROUND: "Deep" extubation, administration of intravenous (i.v.) narcotics, i.v. lidocaine and forestalling local spray of lidocaine have been used to help diminish coughing during emergence. However, the respective efficacy of these techniques has not been concluded. Sconzo et al. indicated that endotracheal tube (ETT) cuff might serve as a reservoir for local anesthetic. Alkalizing and warming are two techniques frequently used to increase in the proportion of uncharged drugs available. Matias indicated that alkalization could prompt a 63-fold increase of the rate of diffusion of lidocaine across the ETT cuff. Huang et al. also observed that alkalization together with warming could achieve a 118-fold increase further. However, the in vivo effects of ETT-cuff lidocaine have not been studied. METHODS: Eighty patients of ASA Class I-II undergoing elective surgeries were included. They were randomly assigned into four groups. After tracheal intubation, the ETT cuff was filled with one of the following solutions: normal saline 6 ml (Group A), 4% lidocaine 6 ml at room temperature (Group B), 4% lidocaine 5 ml + 7% sodium bicarbonate 1 ml at room temperature (Group C), and 4% lidocaine 5 ml + 7% sodium bicarbonate 1 ml warmed to 38 degrees C (Group D). Changes of vital signs as well as the times of coughing in the course of extubation and post-extubation complications were recorded. One way ANOVA (SPSS for windows) was used for data analysis. RESULTS: The respective number of coughing per patient in the experimental groups (Group B, C and D) was significantly less than the saline or control group (mean = 9.70, 9.15 and 3.95, respectively, p < 0.05). The incidence of sore throat in Group C and Group D was significantly less than the control group (35% and 25%, respectively, p < 0.05). Regarding the hemodynamic changes, systolic arterial pressure (SAP) and mean arterial pressure (MAP) were higher in Group B and C (p < 0.05) before extubation. CONCLUSIONS: Alkalized and warmed lidocaine prestored in the endotracheal tube (ETT) cuff can greatly reduce ETT-induced coughing and thus promote a smoother emergence from general anesthesia with endotracheal intubation.

Adolescent↗
PubMed1997

Antisense oligonucleotides against rat brain alpha1E DNA and its atrial homologue decrease T-type calcium current in atrial myocytes.

Low voltage-activated, or T-type, calcium currents are important regulators of neuronal and muscle excitability, secretion, and possibly cell growth and differentiation. The gene (or genes) coding for the pore-forming subunit of low voltage-activated channel proteins has not been unequivocally identified. We have used reverse transcription-PCR to identify partial clones from rat atrial myocytes that share high homology with a member of the E class of calcium channel genes. Antisense oligonucleotides targeting one of these partial clones (raE1) specifically block the increase in T-current density that normally results when atrial myocytes are treated with insulin-like growth factor 1 (IGF-1). Antisense oligonucleotides targeting portions of the neuronal rat alpha1E sequence, which are not part of the clones detected in atrial tissue, also block the IGF-1-induced increase in T-current, suggesting that the high homology to alpha1E seen in the partial clone may be present in the complete atrial sequence. The basal T-current expressed in these cells is also blocked by antisense oligonucleotides, which is consistent with the notion that IGF-1 up-regulates the same gene that encodes the basal current. These results support the hypothesis that a member of the E class of calcium channel genes encodes a low voltage-activated calcium channel in atrial myocytes.

Animals↗