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Biomedical subjects

S Y Chang

Publications and source records attributed to S Y Chang.

At least 55 records · Page 3Linked to original sources

Carbon dioxide laser microsurgery for tongue cancer: surgical techniques and long-term results.

Thirty-seven consecutive patients with cancer of the anterior two-thirds of the tongue without clinical neck lymph nodes or distant metastasis were treated with transoral carbon dioxide (CO2) laser microsurgery. During the operation, a monopolar coagulation-suction device was applied to achieve a clear surgical field. Under a surgical microscope, we repeatedly palpated the soft tissue to identify the tumour margins, in particular the deep margin, to maintain adequate safe margins in three dimensions. We resected the tumour by en bloc procedures rather than by vaporization or debulking. Of the 28 patients in the T1 and T2 groups, 26 patients did not receive postoperative radiotherapy. The local control rate calculated by the methods of Kaplan and Meier in all 37 patients at 5 years was 93.6%. No local recurrence occurred in the T1 or T2 cases. Nine patients suffered from neck recurrence and the neck control rate at 5 years was 74.6%. Eight of these nine patients were salvaged by surgery with adjuvant radiotherapy, and six of them finally achieved disease-free status. The 5-year disease-free survival rate for our series was 88%. Our surgical techniques using CO2 laser microsurgery are effective and advantageous methods for excision of oral tongue cancer, especially stage I and II lesions.

Adult↗

ADP-ribosylating binary toxin genes of Clostridium difficile strain CCUG 20309.

The cdt genes that encode a binary ADP-ribosylating toxin in Clostridium difficile were first characterized from a toxigenic C. difficile strain CD196 in 1997. We report here C. difficile strain CCUG 20309 (ATCC 8864), a strain that produces toxin B but not toxin A, also carry a complete set of cdtA and cdtB genes. These genes were sequenced by cycle sequencing method. The 2 ORFs and the intergenic sequences of these 2 strains have a homology of 99.6%. Interestingly, 9 extra bases were found within the cdtA gene of strain CCUG 20309 which do not affect the downstream region of the ORF. Using the same homologous primers, the highly toxigenic reference strain VPI 10463 was found to carry only parts of the 2 ORFs while a nontoxigenic strain ATCC 8884 does not carry any of the cdt genes. Though it remains to be determined whether these genes are expressed, it is significant that strain CCUG 20309 contains the complete set of cdt genes. We speculate that the putative expressed proteins may contribute to pathogenesis, for example, enterotoxicity, of this unique strain of bacteria.

ADP Ribose Transferases↗

Growth pattern of renal angiomyolipoma on computed tomography: report of two cases.

The incidence of renal angiomyolipoma is increased in patients with tuberous sclerosis. Renal angiomyolipomas frequently exhibit both intratumoral and subcapsular or perirenal hemorrhage when they grow into the extrarenal space. Evidence of serial morphologic change is crucial to decision-making for surgical exploration in patients with growing renal angiomyolipomas. We report two cases of angiomyolipoma of the kidney with expansion of an angiomyolipoma into the subcapsular region. Neither patient had tuberous sclerosis and both developed bleeding when the mushroom-shaped tumor reached the extrarenal space. These cases suggest that expansion of the tumor into the subcapsular region is indicative of impending rupture of a renal angiomyolipoma.

Adult↗

Prenatal diagnosis of persistent fetal bradycardia: report of four cases.

Persistent fetal bradycardia is infrequent in prenatal life and difficult to manage optimally. It is generally attributable to sinus bradycardia due to fetal distress, blocked atrial extrasystoles, and congenital complete heart block. We reported four cases of persistent fetal bradycardia from 1995 to 1999 in our hospital. The first, second, and third cases of sustained fetal bradycardia had congenital complete heart block with positive titers for anti-Ro/SSA antibodies in both mothers and fetuses. Because of progressive fetal hydrops in the second case, the pregnancy was terminated. The first and third cases were isolated congenital complete heart block without structural anomaly. After prenatal examination the babies were followed up closely until term and both had a good prognosis without any implantation of pacemaker. In the fourth case there was no clinically known etiology associated with sustained fetal bradycardia. The fetal heart rate returned to normal after 6 weeks of follow-up and the baby was delivered without any cardiac problems. Congenital complete heart block is the most common cause of persistent fetal bradycardia. Prenatal detailed monitoring until delivery is necessary before heart failure develops. Treatment strategies (corticosteroids, ritodrine, and plasmapheresis) are debatable and may include prophylactic therapy for high-risk pregnant women.

Adrenal Cortex Hormones↗

The expression of neuropeptides in hyperplastic and malignant prostate tissue and its possible clinical implications.

PURPOSE: We characterized the incidence and pattern of distribution of neuroendocrine differentiated tumor cells in prostatic hyperplastic and carcinomatous tissue, correlated neuroendocrine differentiation with prostate specific antigen (PSA) and assessed whether neuroendocrine cells have value as an independent indicator of poor prognosis in patients with prostate carcinoma. MATERIALS AND METHODS: We immunohistochemically evaluated hyperplastic and carcinomatous prostate specimens for chromogranin A, neuron specific enolase and serotonin expressing tumor cells. The expression of various markers in cells was analyzed and correlated with tumor DNA ploidy, disease grade and stage, PSA and clinical course in patients with prostate cancer. RESULTS: Enrolled in our study were 31 patients with hyperplastic prostate tissue and 30 with prostatic carcinoma. Followup in cancer cases was 1 to 9 years (mean 3.7). During followup 9 patients (30%) died of cancer. We noted DNA content aneuploidy in 5 cases (16.7%) of prostate carcinoma. Chromogranin A, neuron specific enolase and serotonin were expressed in 80%, 43% and 77% of cases of prostate carcinoma and in 29%, 10% and 36% of hyperplastic tissue, respectively. Larger prostates had no higher content of various neuroendocrine cells than smaller prostates. There was higher expression of neuropeptides in carcinomatous than in hyperplastic tissue. Of the 3 peptides chromogranin A was significantly related to all parameters, including Gleason score, tumor stage, PSA and patient survival. In addition to PSA, neuron specific enolase was also closely associated with other clinicopathological parameters. Serotonin was significantly related to patient survival only but we noted no correlation with Gleason score, tumor stage or PSA. In regard to factors predictive of patient prognosis expression of the 3 neuropeptides in tumor cells, Gleason score, tumor stage and PSA were closely related to patient survival in this study CONCLUSIONS: The growth of hyperplastic prostate tissue is related to neuroendocrine cell activity. The chromogranin A marker has the highest expression in prostate cancer. Neuroendocrine cells may represent an independent indicator of poor prognosis in patients with prostate carcinoma.

Aged↗

Complestatin is a noncompetitive peptide antagonist of N-methyl-D-aspartate and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate receptors: secure blockade of ischemic neuronal death.

Complestatin, a peptide derived from Streptomyces, was found to protect cultured cortical neurons from excitotoxicity induced by N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), or kainate. This neuroprotective behavior of complestatin was attributed to a blockade of Ca2+ ion entry and accumulation, after the activation of NMDA and AMPA/kainate receptors. Complestatin reversibly interfered with NMDA- and AMPA-mediated excitatory synaptic transmission. Complestatin also protected cortical neurons from prolonged deprivation of oxygen and glucose, more effectively than combined antagonists of NMDA and AMPA/kainate receptors. Neurotoxicity, evolving within 1 to 2 days after continuous exposure to combined NMDA and AMPA/kainate antagonists, was not observed in cortical cell cultures that were exposed to complestatin. Finally, complestatin dose dependently prevented neuronal death evolving within the inner nuclear and ganglion cell layers, after transient retinal ischemia. We conclude that complestatin possesses novel pharmacological properties that effectively prevent excitotoxicity under certain pathological conditions.

Animals↗

Waveforms of the ductus venosus blood flow in normal human fetuses aged 8-38 weeks.

BACKGROUND: We attempted to establish normal Doppler flow velocity waveform patterns in the human fetal ductus venosus (DV), and also to establish a standardized measurement technique. METHODS: Ductus venosus blood flow was measured in a prospective study involving 545 fetuses aged between 8 and 38 weeks in utero, the mothers of whom received prenatal care in Kaohsiung Chang Gung Memorial Hospital in a 12-month period in 1998-1999. Several DV hemodynamic parameters were assessed, including peak systolic velocity (DVP), peak systolic/diastolic (S/D) ratio, time-averaged velocity (TAMX), maximum velocity during atrial contraction (DVM), pulsatility index (PI), Pourcelot's resistance index (RI), and fetal heartbeat (FHB). RESULTS: Technically acceptable ductus venosus blood flow velocity waveform patterns were collected from 490 of 545 pregnant women (89.9%). The mean +/- SD value for the peak systolic DV velocity during the time period of 8 to 38 weeks in utero was 0.33 +/- 0.11 meters/sec (m/s), the TAMX being 0.24 +/- 0.09 m/s. The maximum velocity during atrial contraction was 0.15 +/- 0.09 m/s, and the peak S/D velocity ratio was 2.5 +/- 1.01. The PI, Pourcelot's RI and fetal heart beat were, 0.67(+/- 0.21), 0.64 (+/- 0.11), and 163.3 (+/- 18.82 bpm), respectively. Significant increases in DVP, TAMX, and DVM with advancing gestational age were established, and decreases in PI, RI, S/D, and FHB with advancing gestational age were also observed. CONCLUSIONS: Further investigation of DV hemodynamics throughout pregnancy may enable a greater understanding of normal placental perfusion, the fetal venous return to the heart and associated cardiac function.

Adolescent↗

Isolated craniosynostosis: prenatal ultrasound of scaphocephaly with polyhydramnios.

Craniosynostosis is an abnormal shape or dimension of the skull caused by premature closure of one or more skull sutures. It includes scaphocephaly, brachycephaly, oxycephaly, plagiocephaly, trigonocephaly, turricephaly, and a cloverleaf-shaped head. The only cases of craniosynostosis that have been reported concern fetuses with complex and marked craniosynostosis syndromes such as acrocraniofacial dysostosis, Apert's syndrome, Beare-Stevenson cutis gyratum syndrome, Calabro's syndrome, etc. Isolated or simple craniosynostosis, however, is a developmental anomaly rarely found on routine ultrasound examination. We present a case that was diagnosed as scaphocephaly with moderate polyhydramnios by prenatal ultrasound. No other structural anomaly was detected, and the karyotyping was normal. So isolated sagittal craniosynostosis was diagnosed prenatally and was confirmed by postnatal skull radiography as well as 3-dimensional computed tomography. The infant underwent bilateral parietal craniectomy at the age of 3 months. He obtained a good result with no mental problems 4 years after the operation. To our knowledge, this is the second report on the prenatal detection of an isolated form of craniosynostosis.

Adult↗

Definition and measurement of child malnutrition.

Child Malnutrition has been defined or described in many ways. To summarize the common points, child malnutrition may be defined as a pathological state resulting from inadequate nutrition, including undernutrition (protein-energy malnutrition) due to insufficient intake of energy and other nutrients; overnutrition (overweight and obesity) due to excessive consumption of energy and other nutrients; deficiency diseases due to insufficient intake of one or more specific nutrients such as vitamins or minerals. In the assessment of child malnutrition, a large number of measures are available. Among these measuring methods, Z-score, growth charts, weight-for-length index (WLI), height standard weight, body mass index, skin fold thickness and clinical grading diagnosis standard for child malnutrition are selected for discussion. The same set of anthropometry data of a group of preschool children was analyzed by using different methods. The results showed that it was very difficult to determine the nutritional state of children using a single index. For a given group of children, Z-score method is recommended to observe their height, weight and weight for height at the same time in order to have a comprehensive understanding.

Anthropometry↗

Dietary intake of some essential micronutrients in China.

OBJECTIVE: Based on the data collected in the 1992 national nutrition survey in China, the food consumption and nutrients intake were calculated, and the consumption of some micronutrients was evaluated. METHOD: Dietary data were obtained by using a three days' inventory change plus food weighing in combination with 24 hours recall method for three consecutive days. The food consumption and nutrients intake were calculated in accordance with the Chinese food composition table. The consumption of some micronutrients was evaluated in reference to the Chinese RDAs. RESULTS: The average intakes of niacin, ascorbic acid and vitamin E were sufficient, whereas that of zinc, selenium and thiamin were between 80% and 90% RDAs. The consumption of calcium, retinol equivalent and riboflavin was low compared with the Chinese RDAs. Calcium was the most insufficient nutrient in Chinese diet. CONCLUSION: Food fortification seems necessary for improving the nutritional status of some micronutrients in China.

Adolescent↗

Transcriptional analysis of multiple sclerosis brain lesions reveals a complex pattern of cytokine expression.

Multiple sclerosis (MS) is a common and severe neurological disorder associated with an autoimmune response directed against myelin components within the CNS. Lymphocyte activation, extravasation, and recruitment, as well as effector function, involves the turning on and off of a number of genes, thus triggering specific transcriptional pathways. The characterization of the transcriptome in MS lesions should provide a better understanding of the mechanisms that generate and sustain the pathogenic immune response in this disease. Here we performed transcriptional profiling of 56 relevant genes in brain specimens from eight MS patients and eight normal controls by kinetic RT-PCR. Results showed a high transcriptional activity for the gene coding for myelin basic protein (MBP); however, it was not differentially expressed in MS samples, suggesting that remyelination is an active process also in the noninflammatory brain. CD4 and HLA-DRalpha transcripts were dramatically increased in MS as compared with controls. This reveals a robust MHC class II up-regulation and suggests that Ag is being presented locally to activated T cells. Although analysis of cytokine and cytokine receptor genes expression showed predominantly increased levels of several Th1 molecules (TGF-ss, RANTES, and macrophage-inflammatory protein (MIP)-1alpha) in MS samples, some Th2 genes (IL-3, IL-5, and IL-6/IL-6R) were found to be up-regulated as well. Similarly, both proinflammatory type (CCR1, CCR5) and immunomodulatory type (CCR4, CCR8) chemokine receptors were differentially expressed in the MS brain. Overall, our data suggest a complex regulation of the inflammatory response in human autoimmune demyelination.

Algorithms↗

Interaction between HIV type 1 glycoprotein 120 and CXCR4 coreceptor involves a highly conserved arginine residue in hypervariable region 3.

Several seven-transmembrane chemokine receptors are known to function as entry coreceptors for human immunodeficiency virus type 1. CCR5 and CXCR4 are the major coreceptors for non-syncytium-inducing (NSI) and syncytium-inducing (SI) viruses, respectively. During the natural course of infection, the emergence of variants with a phenotypic transition from NSI to SI and rapid disease progression is associated with expanded coreceptor usage to CXCR4. Characteristic amino acids at several positions in the hypervariable region 3 (V3) of gp120 have been linked to CXCR4 utilization. Previously, we reported that a highly conserved arginine residue of V3 played an important role in CCR5 utilization. In this study, the possible involvement of the same arginine residue in CXCR4 utilization was investigated. Amino acid substitutions introduced to this arginine on R5X4 viruses were found to have a significant effect on their utilization of CXCR4. These results, taken together with those reported previously, suggest that this highly conserved arginine may contribute to the functional convergence of chemokine coreceptor utilization by human immunodeficiency viruses and may represent a unique target for future antiviral design.

Amino Acid Sequence↗

Enhancing effect of polyoxyethylene alkyl ethers on the skin permeation of ibuprofen.

The influence of polyethoxylated non-ionic surfactants on the transport of ibuprofen across rat skin was investigated. The skin permeation of ibuprofen from a series of 17 polyoxyethylene (POE) alkyl ethers containing 5% ibuprofen was determined using Franz diffusion cells fitted with excised rat skins. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were performed for the physicochemical characterization of ibuprofen-surfactant interaction. In vitro transdermal flux through excised rat skin was found in the decreasing order of POE(5)cetyl/oleyl ether (110.24 microg/cm(2)/h)>POE(2)lauryl ether (99.91 microg/cm(2)/h)>POE(2)oleyl ether (67.46 microg/cm(2)/h)>POE(10)stearyl ether (66.19 microg/cm(2)/h). POE(2)oleyl ether showed the longest lag time (2.47 h). The enhancers containing the EO chain length of 2-5, HLB value of 7-9 and an alkyl chain length of C16-C18 were effective promoters of ibuprofen flux. FT-IR and DSC studies to probe the nature of the interaction between the ibuprofen and surfactant indicated that the hydrogen bonding state of ibuprofen was changed from the dimeric form to the carbonyl-hydroxyl (C=O-HO) hydrogen bond form in the presence of excess POE alkyl ether. These results indicated that this new system may be used in developing a transdermal formulation with improved skin permeation of ibuprofen.

Algorithms↗

Human immunodeficiency virus type 1 subtype E envelope recombinant peptides containing naturally immunogenic epitopes.

A series of recombinant peptides of the human immunodeficiency virus type 1 (HIV-1) subtype E envelope were used to address the question of whether immunogenic epitopes similar to those described for the subtype B envelope are also present in structurally analogous regions of another HIV-1 subtype with divergent sequences. Five recombinant peptides, covering the V2 and V3 domains of gp120, the cysteine-loop region of gp41, a gp41 region involved in oligomerization, and the cytoplasmic tail of gp41, were found to react with >50% of the serum samples analyzed. All but the V2 region in the HIV-1 subtype B envelope have been reported to contain continuous epitopes that are highly immunogenic during natural infection. This finding suggests that, despite the sequence divergence between subtype E and B envelopes, most of the continuous epitopes that are highly immunogenic during natural infection are located at structurally analogous regions of the envelope.

Epitopes↗

Analysis of baclofen by capillary electrophoresis with laser-induced fluorescence detection.

A new analytical method for baclofen (4-amino-3-p-chlorophenylbutyric acid) based on capillary electrophoretic separation and laser-induced fluorescence detection has been developed. Naphthalene-2,3-dicarboxaldehyde was used for precolumn derivatization of the non-fluorescent drug. Optimal separation and detection were obtained with an electrophoretic buffer of 50 mM sodium borate (pH 9.5) and a He-Cd laser (excitation at 442 nm, emission at 500 nm). Linearity (r > or = 0.99) over three orders of magnitude was generally obtained and the concentration limit of detection was in the nanomolar level. Coupled with a simple cleanup procedure, the method was successfully applied to the analysis of baclofen in human plasma. Recovery of spiked baclofen in plasma was 98%. The relative standard deviation values on peak size and migration time were 7.9% and 0.4%, respectively. The limit of detection of baclofen in plasma was 10 ng/ml.

Baclofen↗