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Biomedical subjects

L H Chen

Publications and source records attributed to L H Chen.

At least 55 records · Page 3Linked to original sources
PubMed1998

Ankle arthrography and chronic lateral ankle instability.

Sixty-five ankle arthrograms of the patients who underwent surgical reconstruction for their chronic ankle instability from 1987 to 1995 were studied retrospectively by comparing their operative findings. There were 15 cases (23.1%) with definite positive arthrographic findings. In the remaining 50 cases (76.9%), the arthrograms showed a "tear-drop" extravasation of dye beneath the fibular tip which we called "suspectable positive". Of these all but one, which had normal ligament, proved to correspond to the operative finding. As there was only one false positive finding among our surgical cases with both the "definite" and "suspectable" positive arthrograms, we concluded that ankle arthrography is relatively reliable and may be worth doing even in chronic cases if only for reference. Even when other diagnostic methods are negative, arthrography might help surgeons make surgical decisions in clinical symptomatic cases.

Adolescent↗
PubMed1998

Effects of fish oil on cytokines and immune functions of mice with murine AIDS.

The effects of fish oil, which is rich in n-3 fatty acids, on cytokine levels in a murine model of acquired immune deficiency syndrome (AIDS) were studied. Thirty-two C57BL/6 female mice were divided into two dietary groups and fed either a corn oil diet or a fish oil diet. After 4 weeks, each diet group was further divided into two subgroups, and mice in one subgroup were injected i.p. with LP-BM5 murine retrovirus (MAIDS) stock. After 4 weeks, all mice were killed, blood samples were collected, and the spleens and the livers were excised. Splenocytes were isolated immediately and cultured in RPMI-1640 medium and stimulated by either lipopolysaccharide (LPS) or Concanavalin A (ConA) for 24 h. The supernatant was collected for cytokine assays. The results showed that MAIDS infection increased the levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1-beta (IL-1beta), while fish oil partially prevented this elevation. MAIDS infection depressed interleukin-2 (IL-2) and interferon-gamma (IFNgamma), while fish oil partially prevented the depression of IL-2. In addition, MAIDS infection depressed LPS- and ConA-stimulated cell proliferation, while fish oil partially prevented the depression. The results suggest that fish oil may slow down the progression of murine AIDS by modulating levels of cytokines including TNF-alpha, IL-1beta, and IL-2.

Animals↗
PubMed1998

Solitary osteochondroma of the lumbar spine with cord compression: a case report.

Solitary osteochondromas are usually of little significance. However, if they are located near neurologic structures, they may cause irritation due to compression. Spinal cord compression is a rare but potentially catastrophic manifestation of solitary osteochondromas. As far as can be ascertained, a solitary osteochondroma in the lumbar region with spinal cord compression has not been reported in Taiwan. This article includes the treatment of an 11-year-old girl with osteochondromas which was complicated by the late development of kyphoscoliosis and a review of the literature.

Child↗
PubMed1998

Pyomyositis in childhood: a case report.

Pyomyositis is a primary infection of skeletal muscle. We report the case of a previously healthy six-year-old who suffered from pyomyositis in the right lower back. He presented with lower back pain and low-grade fever for one week. After a series of laboratory and imaging studies, the diagnosis of right multifidus muscle pyomyositis with abscess formation was made. The patient recovered rapidly after incision and drainage therapy, accompanied by antibiotic treatment. Methicillin-resistant Staphylococcus aureus was cultured from the abscess discharge. It was strongly suspected that herbal medicines and common cold medication the patient had been prescribed before admission to our hospital produced a masking effect that delayed the diagnosis.

Child↗
PubMed1997

Human methionine synthase. cDNA cloning, gene localization, and expression.

Human cDNAs for methionine synthase (5-methyltetrahydrofolate:L-homocysteine S-transmethylase; EC 2.1.1. 13) have been isolated from fetal and adult liver and HepG2 libraries. The cDNAs span 7.2 kilobases (kb) and consist of a 394-base pair upstream untranslated region, a 3795-base pair open reading frame encoding a 1265-residue 140.3-kDa protein, and about 3 kb of 3' region. The deduced protein sequence shares 53 and 63% identity with the Escherichia coli and the presumptive Caenorhabditis elegans proteins, respectively, and contains all residues implicated in B12 binding to the E. coli protein. Several potential polymorphisms and a cryptic splice deletion were detected in the coding region of the cDNAs. A polymorphism that results in a D919G modification in the protein is fairly common in human DNA samples. Northern analyses of poly(A) mRNA indicated two major species of about 8 and 10 kb in human tissues and some minor, partially spliced species. mRNA levels were highest in the pancreas, skeletal muscle, and heart of the adult and in the kidney in the fetus and were low in adult liver. Genomic clones were isolated and the 5' region was analyzed. Exon 1 is preceded by a number of potential promoter sites, including an E box, CAAT boxes, and a GC box, but this region lacks a TATA element. The human methionine synthase gene was localized to chromosome region 1q42.3-43 by in situ hybridization.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1997

Molecular cloning, characterization, and regulation of the human mitochondrial serine hydroxymethyltransferase gene.

The human mitochondrial serine hydroxymethyltransferase (mSHMT) gene was isolated, sequenced, and characterized. The 4.5-kilobase gene contains 10 introns and 11 exons, with all splice junctions conforming to the GT/AG rule. The 5' promoter region contains consensus motifs for several regulatory proteins including PEA-3, Sp-1, AP-2, and a CCCTCCC motif common to many genes expressed in liver. Consensus TATA or CAAT sequence motifs are not present, and primer extension and 5'-rapid amplification of cDNA ends studies suggest that transcription initiation occurs at multiple sites. The mitochondrial leader sequence region of the deduced mRNA contains two potential ATG start sites, which are encoded by separate exons. The intervening 891-base pair intron contains consensus promoter elements suggesting that mSHMT may be transcribed from alternate promoters. 5'-Rapid amplification of cDNA ends analysis demonstrated that the first ATG is transcribed in human MCF-7 cells. However, transfection of Chinese hamster ovary cells deficient in mSHMT activity with the human mSHMT gene lacking exon 1 overcame the cell's glycine auxotrophy and restored intracellular glycine concentrations to that observed in wild-type cells, showing that exon 1 is not essential for mSHMT localization or activity and that translation initiation from the second ATG is sufficient for mSHMT import into the mitochondria. Mitochondrial SHMT mRNA levels in MCF-7 cells did not vary during the cell cycle and were not affected by the absence of glycine, serine, folate, thymidylate, or purines from the media.

Amino Acid Sequence↗
PubMed1997

Effect of infection brain edema on NMDA receptor binding in rat brain in vivo.

The purpose of this study was to determine the effect of infection brain edema (IBE) in the rat model induced by injecting pertussis bacilli (PB) into the left carotid artery. The specific binding of N-methyl-D-aspartate (NMDA) receptor with [3H] MK-801 was measured in the neuronal membrane of cerebral cortex. The Scatchard plots were performed. The Bmax values were 0.623 +/- 0.082 and 0.606 +/- 0.087 pmol/mg protein in the group that received normal saline (NS) and PB respectively (P < 0.05). The Kd values were 43.1 +/- 4.2 and 30.5 +/- 3.0 nM in the groups NS and PB respectively. The results indicated that the affinity of NMDA receptor was significantly higher in the group PB than group NS, whereas the total number of NMDA receptors had not changed in the IBE model. The increase of affinity of NMDA receptor can be blockaded by MK-801 pretreatment in vivo.

Animals↗
PubMed1997

Survivorship analysis of DKS instrumentation in the treatment of spondylolisthesis.

This retrospective study analyzed the survivorship of DKS instrumentation and the clinical outcomes in 185 patients with spondylolisthesis. These patients were treated with Zielke DKS instrumentation for a mean followup period of 3.5 years. Eight (4.3%) patients had late removal of implants, 25 (14%) had rod breakage, three (1.7%) had screw breakage, and 16 (8.7%) had nut loosening. The survivor rate of DKS instrumentation was 96% within 3 months after operation, 80% at 2 years, and 61% at 5 years after surgery. One hundred sixty-three (88%) patients had solid posterolateral fusion, and 167 (90%) patients had good to excellent results. Adjacent instability developed in 18 (9.7%) patients. Although Zielke DKS instrumentation has a smaller rod and relatively insecure locking system between the rod and screw, it is an effective implant for the treatment of spondylolisthesis.

Adult↗
PubMed1997

Acute toxicities and feasibility of altered fractionated radiotherapy in nasopharyngeal carcinoma.

BACKGROUND: Altered fractionated radiotherapy (AFR) has been used for many years in the treatment of cancer. Although AFR therapy improves tumor control, it also increases acute radiation toxicities, which may make patients withdraw from treatment. Here, we report on the efficacy of AFR in the treatment of nasopharyngeal cancer (NPC). METHODS: From September 1993 to October 1994, 68 NPC patients received AFR in Chang Gung Memorial Hospital-Linkou. The efficacy of two types of AFR were studied: (a) Hyperfractionated radiotherapy (HFT) in which irradiation was given twice a day throughout the radiotherapy course with a total radiation dose of 81.6 Gy/68 fractions in 7 weeks; and (b) Concomitant boost radiotherapy (CBT) in which additional concommitant radiotherapy was administered only during the last 2 weeks of the radiotherapy course. The total radiation dose of CBT was 72.3 Gy/42 fractions in 6 weeks. Twenty-six patients received HFT and 42 received CBT. RESULTS: The percentage of grade 3 complications was 73% in CBT and 65% in HFT. The mean number of treatment days was 57.1 in HFT (median, 53; range 48-63) and 43.9 in CBT (median, 43; range 40-60). No patient withdrew from or prolonged the treatment because of acute radiation toxicities. CONCLUSION: Our results demonstrated that NPC patients can tolerate HFT and CBT radiotherapy with sufficient psychological support. Further randomized trials will be continued in our institution.

Adolescent↗
PubMed1997

Three cases of fatal pulmonary embolism in obstetrics.

We conducted a retrospective analysis of maternal deaths in our hospital from January 1992 to December 1995. Cases of fatal pulmonary embolism were identified and analysed with respect to their past history, antenatal and peripartum progress, clinical presentation and investigation. There were 7 maternal deaths during this period and autopsies were performed in all cases. Pulmonary embolism was the leading cause of maternal mortality, responsible for 3 deaths. The incidence of fatal pulmonary embolism was 4.9 per 100,000 maternities. One case occurred antepartum and 2 occurred postpartum. The antepartum case occurred after a period of immobilisation, and both postpartum cases occurred after emergency Caesarean sections. Dyspnoea and sudden cardiovascular collapse were the commonest presentations. Electrocardiograph and arterial blood gases were abnormal in both patients in whom the tests were performed. Death occurred within 11 hours of presentation of symptoms in all 3 cases. Pulmonary embolism was more common among our population than previously reported, and was the leading cause of maternal mortality in our institution over the last 4 years. Immobilisation and Caesarean section were the major risk factors. Identification of high risk situation, antithrombotic prophylaxis and a high degree of suspicion were the key to reducing the incidence of fatal pulmonary embolism in obstetric patients.

Adult↗
PubMed1997

Surgical treatment of pathologic fracture of the femur.

A retrospective study of the surgical treatment of 32 metastatic lesions of the femur in 30 patients at the Kaohsiung Medical College Hospital was performed from 1987 to 1994. There were 16 women and 14 men with an average age of 61 years. A surgical technique combining internal fixation or prosthesis and methylmethacrylate cement was used in all cases. Adequate pain relief was achieved in thirty-one cases (97 %). Of the entire group, 20 cases (62%) remained ambulatory, 10 cases (31%) were confined to a wheelchair, only two cases had implant failure and one suffered from infection.

Adult↗
PubMed1997

Salvage operation for neglected ankle fractures.

From 1986 to 1993, 49 cases of untreated or poorly treated ankle fractures who received salvage surgery were followed up for an average of 36.4 months. The patients included 31 males & 18 females with an average age of 41.6y/o and the time interval from initial injury to reconstructive surgery average due 17.6 months. They were classified and treated according to their grade of reduction and degree of arthrosis. The surgical methods included arthrotomy & joint debridement, revised open reduction, lower tibial osteotomy and ankle arthrodesis, depending on different individual conditions. After surgery, all cases had symptomatic relief and functional improvement with an average score increased from 26.3 preoperatively to 86.8 at follow up. The goals of ankle fractures is as articular fractures, they are treated by surgical anatomic reduction with rigid fixation as early as possible in order to provide good functional results. Nevertheless they are varied in neglected ankle fractures according to their individual conditions: open reductions were performed on cases with no or little arthritic change even though arthrosis might occur later because, if necessary, future conversion to osteotomy or arthrodesis would be easier. As for late cases with advanced arthritis, ankle arthrodesis were done by compressive arthrodesis with necessary bone graft to secure fusion in an optimal position.

Adolescent↗
PubMed1997

Concurrent 5-fluorouracil, leucovorin, etoposide, cisplatin and radiotherapy for locally advanced non-small cell lung cancer.

BACKGROUND: The prognosis of Stage III unresectable non-small cell lung cancer may be improved by concurrent chemoradiotherapy. In this study, we attempted to evaluate the feasibility, tolerance, efficacy and toxicities of the combination of thoracic radiation and chemotherapy with a novel regimen that included 5-fluorouracil, leucovorin, etoposide and cisplatin (the FLEP regimen) in the treatment of this group of patients. PATIENTS AND METHODS: From July 1995 to September 1996, 20 untreated patients with locally advanced non-small cell lung cancer were enrolled in the study. Radiation at a dose of 44 Gy was initially delivered in daily fractions of 2 Gy 5 days a week to the tumor and mediastinum, followed by a boost to the tumor (20 to 26 Gy according to patients tolerance). Concurrently with thoracic irradiation, patients were treated with chemotherapy consisting of cisplatin at the dose of 60 mg/m2/d for 1 day, etoposide at the dose of 60 mg/m2/d for 2 days, and 5-FU 500 mg/m2/d plus leucovorin 50 mg/d infusion for 48 hours. Cycles of chemotherapy were repeated every 3 weeks for a maximum of 3 cycles. RESULTS: Seventeen of 20 patients were assessable. The overall response rate was 70.6% (95% confidence interval = 49-92%). No complete response was achieved. The median response duration for all responding patients is not yet estimable, with a range of 3.5 to 15.5+ months. Eleven patients remain progression-free for 4 to 15 months. The median survival for the entire group is not estimable. The major toxicity was esophagitis. Other grade 3 or 4 toxicities were not frequently observed. CONCLUSION: Combined-modality therapy with FLEP regimen and radiation is a promising treatment with a high response rate and acceptable toxicity for locally advanced non-small cell lung cancer.

Adult↗
PubMed1997

The efficacy of intrathecal coadministration of morphine and bupivacaine for labor analgesia.

BACKGROUND: Intrathecal (i.t.) opioids can provide labor analgesia, but the onset of pain relief is slow. Bupivacaine has the beneficial property of less motor blockade than other local anesthetics. This study retrospectively examined the efficacy of concomitant use of i.t. morphine and bupivacaine for labor pain relief. METHODS: Fifty five nulliparas who requested analgesia in the active phase (IA group) prior to a cervical dilation 3.9 +/- 0.6 cm and received i.t. morphine 0.5 mg and 0.1% bupivacaine 2.5 mg served as the treatment group, and 88 similar nulliparas who did not request and receive analgesia served as the control group. RESULTS: The mean onset time of analgesia was 2.6 +/- 0.5 min, the duration was 4-12 h and 93% of parturients did not request additional analgesia after a single injection of i.t. morphine and bupivacaine. The active phase of the first and second stages of labor in the treatment group were significantly longer [318 +/- 214 min vs. 176 +/- 120 min; 74 +/- 29 min vs. 37 +/- 26 min]. Frequency of instrument-assisted vaginal delivery was higher compared with the control group (30.9% vs. 14.1%). However, there were no significant differences in the rate of cesarean section and the Apgar scores of newborns at 1 min and 5 min between the treatment and control group. The major side effects of the treatment group included pruritus (48%), nausea (40%), vomiting (37%), somnolence (27%), shivering (27%), urinary retention (21%), hypotension (15%), and bradycardia (13%). Most of the side effects were mild and could be alleviated by naloxone. Neither post-spinal headache nor respiratory depression was noted. CONCLUSIONS: Our results showed that a single injection of i.t. morphine and bupivacaine provided rapid onset and effective analgesia with manageable side effects and without major complications. Thus, i.t. morphine and bupivacaine provides an alternative to epidural analgesia for most women in labor.

Adult↗
PubMed1997

[Role of cytosolic calcium balance on cell injury in cultured bovine aortic endothelial cells during hypoxia and reoxygenation].

Making use of an in vitro model of bovine aortic endothelial cell monolayers, the cell viability and changes of intracellukar calcium concentration of the preparation were submitted to hypoxia with or without reoxygenation. It was shown that the cell viability declined under hypoxia but increased under reoxygenation when the endothelial cells were incubated in calcium-free HBSS, as compared with control HBSS incubation. It was observed that a significant reduction of intracellular calcium from 99 to 69 nmol/L during 2 h of hypoxia, which was further decreased in Ca(2+)-free HBSS medium. After 4 h hypoxia followed by 40 min reoxygenation, [Ca2+]i recovered to the nomal concentration. It is speculated that the calcium homeostasis may be an important condition for cells to carry out normal function and either decrease or increase of [Ca2+]i may injury bovine aortic endothelial cells.

Animals↗
PubMed1997

[Differences between effects of hypoxia on rabbit aorta and pulmonary artery].

The difference of morphological injury between rabbit aorta and pulmonary artery was compared after the animal was exposed to the altitude 5 km (PO2 = 10.8 kPa) for 24 h. Hypoxia caused subendothelial edema, increased vacuoles and injured mitochondria and endoplasmic reticulums in both kinds of endothelial cells. The impairment of pulmonary artery was obviously more severe than aorta and its smooth muscle cells were also affected. Forthermore, the exposure increased mitochondria in pulmonary artery endothelial cells. Bubbled with a mixture air of 95% N2-5% CO2 (PO2 = 4 kPa) led to an increase of pulmonary in tension, while hypoxia to the same extent induced aorta relaxation. These results indicate that hypoxia produces the differential effects on these two kinds of vessels, providing a possible explanation for the production of hypoxic pulmonary hypertension.

Altitude↗
PubMed1996

Rabbit muscle creatine kinase: consequences of the mutagenesis of conserved histidine residues.

Creatine kinase (CK; EC 2.7.3.2) catalyzes the reversible conversion of creatine and MgATP to phosphocreatine and MgADP. In the absence of an X-ray crystal structure, we have used the sequence homology of creatine kinases and other guanidino kinases from a variety of sources to identify the conserved histidine residues in rabbit muscle CK, as well as to try to pinpoint a reactive histidine that has been implicated in the active site. This residue has been proposed to act as a general acid/base catalyst assisting in the phosphoryl transfer mechanism [Cook et al. (1981) Biochemistry 20, 1204-1210]. There are 17 histidine residues in rabbit muscle CK, and of these, only five have been conserved in all guanidino kinase sequences published to date [Mühlebach et al. (1994) Mol. Cell. Biochem. 133, 245-62]. In rabbit muscle CK, these residues are H96, H105, H190, H233, and H295. We have carried out site-specific mutagenesis of these five histidine residues, replacing each with an asparagine. Each of these mutants exhibited enzymatic activity but to varying degrees. The H105N, H190N, and H233N mutants displayed specific activities similar to that of the wild-type enzyme. H96N has high activity, but appears to be quite unstable, losing catalytic activity upon cell lysis by sonication and/or chromatographic steps involved in purification. H295N shows a significantly reduced catalytic activity relative to the native enzyme, due to marked decreases in kcat and the affinities for both substrates. Each of the five mutants is inactivated by diethyl pyrocarbonate (DEP), and inactivation is reversible upon incubation with hydroxylamine. However, only H295N shows a dramatically reduced rate of inactivation relative to native CK, consistent with H295 being the residue modified by DEP in the native enzyme. These intriguing results indicate that four of the conserved histidines (H96, H105, H295, and H233) are not essential for activity, and while H295 may be at the active site of CK, it is unlikely to play the role of a general acid/base catalyst.

Amino Acid Sequence↗