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Biomedical subjects

B H Chen

Publications and source records attributed to B H Chen.

At least 19 recordsLinked to original sources
PubMed2000

Anterior cervical fusion: a finite element model study on motion segment stability including the effect of osteoporosis.

STUDY DESIGN: Three-dimensional, nonlinear finite element models were used to evaluate the stability of the mid cervical spine after anterior fusion in patients with and without osteoporosis. OBJECTIVES: The objective of this study was to compare the change in flexibility of C5-C6 after anterior discectomy with both loose-fitting and tight-fitting fusion graft. SUMMARY OF BACKGROUND DATA: Many factors such as surgical technique, osteoporosis, and excess neck motion during the postoperative period may contribute to fusion failure. Knowledge about changes in biomechanical properties after the surgical procedure is important for selection of grafts with appropriate strength and for guiding patients in postoperative care and rehabilitation. METHODS: Analyses with anterior fusion models with both loose-fitting and tight-fitting graft were performed in a normal and an osteoporotic spine. The motion of the C5 vertebra in relation to the C6 vertebra were calculated, after multidirectional moment loads of 0.5 Nm combined with a compressive preload of 105 N. RESULTS: Loose-fitting graft produced both an increase and a decrease in motion under various external moment loads, with graft compressive stress below the compressive strength of the graft material. A reduction in motion was observed under all moment loads when a tight-fitting graft was used. The compressive stress in the tight-fitting graft was higher than the strength of the graft material. Osteoporosis increased the principal motions with both the loose-fitting graft and tight-fitting graft. Maximum increase in motion with a loose-fitting graft construct was observed under extension and axial torsion moment loads. CONCLUSIONS: Anterior discectomy and insertion of the loose graft resulted in increased motion. A tight-fitting graft is beneficial in reducing motion, but the stress within the graftincreases beyond the graft strength. The presence of osteoporosis was nominally significant when the graft was tight fitting.

Adult↗
PubMed1999

The influence of age at onset and gender on the HLA-DQA1, DQB1 association in Chinese children with insulin dependent diabetes mellitus.

Certain alleles of human leukocyte antigen (HLA)-DR and -DQ genes have been strongly associated with susceptibility and resistance to insulin- dependent diabetes mellitus (IDDM). To further clarify the association of HLA DQ alleles with IDDM and the influence of age at onset and gender on the association with IDDM, we investigated the association of HLA-DQA1, -DQB1 in 54 childhood onset Chinese (21 male) IDDM patients and 65 normal controls by using polymerase chain reaction-sequence specific primer (PCR-SSP). The mean age plus or minus SD at onset of IDDM patients was 8.37+/-3.54 year old. Our results revealed that the frequencies of DQA1 *0301, *0302, DQB1 *0201, and *0302 in IDDM patients were significantly higher than that in the control group (p < 0.025, < 0.005, < 0.001, and < 0.001, respectively). The frequency of DQA1 *0301, *0302, DQB1 *0201, and *0302 were susceptible alleles to IDDM with relative risks of 2.0, 3.5, 5.0 and 4.3, respectively. The protective alleles to IDDM were DQA1 *0101, *0103, DQB1 *0301, *0503, and *0602. We divided IDDM patients into three groups according to age at onset (1-5, 6-10, and 11-15 years old). The frequency of DQA1 *0302 decreased as age increased, and the frequency of DQA1 *0501 increased as age increased. Our results also showed that male IDDM patients had higher frequencies of DQA *0501, DQB1 *0201 than female IDDM patients (p < 0.025 and < 0.025, respectively), while female IDDM patients had higher frequencies of DQB1 *0502 than male IDDM patients (p < 0.05). In our study significant susceptibility haplotypes to IDDM were DQA1 *0301-DQB1 *0302, DQA1 *0501-DQB1 *0201, DQA1 *0301-DQB1 *0201, and DQA *0302-DQB1 *0201.

Adolescent↗
PubMed1999

Virtual endoscopy using perspective volume-rendered three-dimensional sonographic data: technique and clinical applications.

OBJECTIVE: We present a technique for obtaining three-dimensional external and virtual endoscopy views of organs using perspective volume-rendered gray-scale and Doppler sonographic data, and we explore potential clinical applications in the carotid artery, the female pelvis, and the bladder. CONCLUSION: Using the proposed methods, radiologists will find it possible to create virtual endoscopy and external perspective views using sonographic data. The technique works well for revealing the interior of fluid-filled structures and cavities. However, expected improvements in computer performance and integration with existing sonographic equipment will be necessary for the technique to become practical in the clinical environment.

Carotid Arteries↗
PubMed1999

Formation of heterocyclic amines in a model system during heating.

The formation of heterocyclic amines (HAs) in a model system during heating at 100, 150, or 200 degrees C for varied lengths of time was studied. The following systems were used: (i) phenylalanine, (ii) creatinine, (iii) phenylalanine and glucose, (iv) phenylalanine and creatinine, (v) glucose and creatinine, and (vi) phenylalanine, glucose, and creatinine. Results showed that HAs could only be found in both systems of glucose and creatinine, and of phenylalanine, glucose, and creatinine. Both 2-amino-9H-pyrido-[2,3-b]indole (AalphaC) and 2-amino-3-methyl-9H-pyrido-[2,3-b]indole (MeAalphaC) were observed in the former system, and the formation rate of AalphaC was higher than MeAalphaC. For the latter system, 2-amino-3-dimethylimidazo[4,5-f]quinoxaline (IQx), 9H-pyrido-[4,3-b]indole (Norharman), 1-methyl-9H-pyrido-[4,3-b]indole (Harman), AalphaC, and MeAalphaC were present. The formation rate of AalphaC was the highest at 200 degrees C, followed by MeAalphaC, Harman, Norharman, and IQx. In addition, the varieties of HAs increased both with increasing heating time and temperature. The amounts of HAs formed were less in the model system of glucose and creatinine than that of phenylalanine, glucose, and creatinine. The same trend was also observed for the formation rate of HAs. At 150 or 200 degrees C, the amounts of IQx, Harman, Norharman, AalphaC, and MeAalphaC increased in the initial period of heating and then reached a plateau. The results of this study provided a basic understanding of the conditions that result in the formation of HAs during cooking of meat and fish products.

Amines↗
PubMed1999

Effect of different anticoagulant, underfilling of blood sample and storage stability on selected hemogram.

We collected blood samples from 94 adult non-hematological outpatients and inpatients for complete blood count (CBC) without any flagging at Kaohsiung Medical College Hospital in order to investigate the effect of (1) different anticoagulants with Na2 EDTA vs K3 EDTA (2) the underfilling of blood collection volume (2 ml, 3. 5 ml vs standard 5 ml) (3) the difference in storage stability between 1 hour, 4 hours, 8 hours and 12 hours after venesection at room temperature on some selected hemogram parameters (WBC, RBC, hemoglobin, hematocrit, MCV, MCH, MCHC, platelet, percentage of neutrophil and lymphocyte). The automated hematology analyzer we used was SYSMEX NE-8000, (TOA, Japan). All the EDTA collection vacutainer tubes were supplied by Becton-Dickinson (New Jersey, U. S. A.) with the same lot number. Paired t- test was used for statistics. We found that values of hemoglobin, hematocrit, MCV and lymphocyte percentage collected in Na2 EDTA tubes were significantly higher than those collected in K3 EDTA (P < 0.05 for hemoglobin and lymphocyte percentage, and P all < 0.01 for others), while values of MCHC collected in Na2 EDTA were significantly lower than those collected in K3 EDTA (P < 0.05). For underfilling of blood sample, values of hematocrit and MCV with 2 ml blood volume were significantly lower than those with 5 ml blood volume (both P < 0.01), while values of MCHC with 2 ml blood volume were significantly higher than those with 5 ml blood volume (P < 0.01). When the collection blood volume was increased to 3.5 ml, there were no significant difference between values for 3.5 ml and 5ml blood volume (P all > 0.05). In the storage stability study, there was a significant sequential increase of hematocrit and MCV between 1 hour, 8 hours and 12 hours (P < 0.05 and < 0.01, respectively, for 8 hours, P all < 0.01 for 12 hours). There was also a significant sequential decrease of neutrophil percentage between 1 hour and 4, 8, 12 hours' storage at room temperature (P all < 0.01).

Adult↗
PubMed1999

Diabetes insipidus in Langerhans' cell histiocytosis: report of a case.

The incidence of diabetes insipidus secondary to Langerhans' cell histiocytosis (LCH) varies among different reports, ranging from 9.5 to 50%, but it has never been reported in literature in Taiwan. Therefore, we presented a case suffering from polyuria, polydipsia, body weight loss for more than one year and seborreic dermatitis-like skin lesions over the scalp and trunk for more than two years. Her body weight and body length were both less than 3 percentile. Fluid restriction and vasopressin test were performed to differentiate nephrogenic from neurogenic diabetes insipidus. Skin biopsy revealed picture of LCH and LCH with complete central diabetes insipidus was diagnosed. Brain MRI and other laboratory examinations were all within normal limits. She received nasal DDAVP treatment and chemotherapy with TPOG-H 94 protocol. After 3 months treatment, her skin lesions disappeared and daily urine amount returned to normal range.

Child, Preschool↗
PubMed1999

Seroprevalence of CMV antibodies in a blood donor population and premature neonates in the south-central Taiwan.

Infection of cytomegalovirus (CMV) via contaminated blood may endanger immunocompromised patients that require transfusion therapy. The aim of this study is to determine the prevalence of CMV antibodies in the blood donor population in Southern-central Taiwan. A total of 1800 consecutive sera, obtained from Tainan Blood Center of Chinese Blood Services Foundation (CBSF), were tested for CMV antibodies by two commercial enzyme immunoassays (EIAs). Of the sera tested, 150 (8.3%) were found to be CMV seronegative. The frequency of CMV seropositivity revealed no significant difference between male and female donors. The frequency of CMV seronegativity showed a stepwise decrease with the increase of donor age. In addition, the prevalence of HBsAg, antibodies to hepatitis C virus (anti-HCV), antibodies to human immunodeficiency viruses type 1 and 2 (anti-HIV 1 + 2) and antibodies to human T-cell lymphotropic viruses type I and II (anti-HTLV I/II) were compared between CMV seropositive and seronegative groups. Our results showed that there was no significant difference in seroprevalence of these markers between CMV seropositive and seronegative groups. Our findings also showed that six out of twenty (30.0%) premature neonates were CMV-seropositive. These premature specimens and those EIA discrepancy samples were confirmed by specific nucleic acid amplification using polymerase chain reaction (PCR). Our results suggest that a program which aims to supply CMV seronegative blood or blood components to the patients, should not solely depend on current antibody screening methods in an area where CMV infection is highly endemic. Amendments such as PCR testing, leukocyte reduction by filtration before transfusion may be more practical.

Adolescent↗
PubMed1999

Comparison of serum copper, magnesium, zinc and calcium levels between G6PD deficient and normal Chinese adults.

Minerals are important for normal hematopoiesis and may play a role in acute hemolytic anemia induced by G6PD deficiency. To compare serum magnesium, copper, zinc and calcium levels between G6PD deficiency and normal control adults, we investigated 69 G6PD deficient (28 male, 41 female) and 61 age- matched G6PD normal adults (26 male, 35 female). Serum magnesium, copper, zinc and calcium levels were determined by atomic absorbance spectrometry. Our results revealed that male adults with G6PD deficiency had significantly higher serum copper and magnesium levels than those of the control group (P < 0.01, < 0.05, respectively). In G6PD normal adults, serum copper levels were significantly lower in males than in females (P < 0.01). In the group of G6PD deficiency adults, serum copper levels in males (103.0 +/- 10.4 ug/dL) were significantly lower than those in females (139.0 +/- 34.3 ug/dL) (P < 0.01). Serum magnesium values and zinc values in males (2.42 +/- 0.38 mEq/L and 102.2 +/- 26.5 ug/dL) were significantly higher than those in females (2.07 +/- 0.20 mEq/L and 87.0 +/- 14.9 ug/dL) (P all < 0.01). Female adults with G6PD deficiency had significantly higher serum calcium levels and lower magnesium levels than those of the control group (P all < 0.01). The significantly higher levels of serum copper and magnesium in G6PD deficient male adults may play some role concerning red blood cells in resistance to plasmodium falciparum.

Adult↗
PubMed1998

Production of a chimeric form of CD23 that is oligomeric and blocks IgE binding to the Fc epsilonRI.

The low affinity receptor for IgE (Fc epsilonRII/CD23) has previously been shown to interact with IgE with a dual affinity. Three chimeric constructs were created containing the lectin domain (amino acids 172-188) or the "neck" and lectin domain (amino acids 157-188) attached to subunits of oligomeric proteins. All chimeras were incapable of interacting with IgE with either a high or low affinity, indicating that the alpha-helical stalk of CD23 is important for orienting the lectin heads such that an interaction with IgE can occur. This concept received further support in that a chimeric CD23 composed of the human CD23 stalk and the mouse CD23 lectin head bound mouse IgE with a dual affinity, but could only bind rat IgE with a low affinity. Effort was next concentrated on a construct consisting of the entire extracellular (EC) region of CD23. A mutation to the first cleavage site of CD23 (C1M) resulted in a more stable molecule as determined by a decrease of soluble CD23 release. A soluble chimeric EC-C1M was prepared by attaching an isoleucine zipper to the amino terminus (lzEC-C1M). The interaction with IgE by lzEC-C1M was found to be superior to that seen with EC-CD23. The lzEC-C1M could inhibit binding of IgE to both CD23 and the high affinity receptor for IgE, Fc epsilonRI, providing further evidence for a strong interaction with IgE. Fc epsilonRI inhibition (approximately 70%) was seen at equimolar concentrations of lzEC-C1M, implying the effectiveness of this chimera and suggesting its potential therapeutic value.

Animals↗
PubMed1998

International Programme on Chemical Safety (IPCS) environmental health criteria on boron human health risk assessment.

The International Program on Chemical Safety (IPCS), a collaborative program of the United Nations Environment Program, the International Labour Organization (ILO), and the World Health Organization (WHO), includes the Environmental Health Criteria (EHC) Program inaugurated in 1973 by WHO. These EHC are integrated evaluations of the human health and environmental risks from exposure to specific chemicals carried out by a group of international scientists. Boron (B) was evaluated at an IPCS Task Group (TG) convened in November 1996. All TGs are convened under WHO rules and procedures. These procedures relate the overall process used to prepare an EHC including transparency of the process, conflict of interest, the roles of Members and Observers, and the conduct of the TG. The scope and purpose of an EHC, for an element such as B, and its possible role in national and international chemical safety programs will be discussed. In the early 1990s, countries asked that IPCS request TGs to prepare, where data permit, health-based guidance values (GVs) (both total daily intake and to recommend health-based guidelines for various environmental media). This final evaluation in an EHC reflects the collective consensus view of the TG Members. To foster the use of consistent methodology by TGs, IPCS prepared in 1994 an EHC on the methodology for the preparation of GVs for human exposure limits (EHC 170). In developing their final evaluation, TGs have been asked to consider using this methodology. This was done by the TG on B, and a total daily intake for humans of 0.4 mg/kg body wt was derived from animal studies of reproductive and developmental effects in rodents and pharmacokinetic data from both animals and humans. The application of the methodology described in EHC 170 regarding choice of critical effect and uncertainty factors will be discussed.

Animals↗
PubMed1998

Simultaneous multiple viral infections in childhood acute lower respiratory tract infections in southern Taiwan.

Thirty paediatric patients with acute lower respiratory tract infections (ALRI) caused by simultaneous multiple viral infections (SMV) in a 3-year interval were reviewed. Twenty patients were infected with two viruses simultaneously; nine patients with three viruses; and one patient with four viruses. The frequency of individual viruses were: adenovirus, 18 (60 per cent); respiratory syncytial virus, 7 (23 per cent); influenza virus type A, 6 (20 per cent); influenza virus type B, 15 (50 per cent); parainfluenza virus type 1, 11 (37 per cent); parainfluenza virus type 3, 13 (43 per cent). There was no difference between the clinical presentations of ALRI with SMV and those of ALRI with a single virus. In conclusion, SMV was not uncommon in children with ALRI; the clinical presentations of multiple viral infection were similar to those of single viral infection.

Acute Disease↗
PubMed1998

Formation of heterocyclic amines in cooked chicken legs.

The effects of frying and microwave cooking on generation of heterocyclic amines (HAs) in chicken legs with skin and without skin were studied. Chicken legs were microwave-cooked at 2,450 MHz for 5, 10, and 15 min with an output power of 700 W. Frying of chicken legs was conducted at 100 and 150 degrees C for 15 min and at 200 degrees C for 5, 10, and 15 min. The various HAs were analyzed by HPLC with diode-array detection. Results showed that both the varieties and contents of HAs and the weight losses of chicken legs increased along with increasing cooking temperature and time. With skin both the amounts of HAs and weight losses of chicken legs were less than those without skin under the same heating conditions. The weight losses of microwave-cooked chicken legs were higher than those of fried chicken legs. The formation of the aminomethylimidazoquinoline type of HAs could be reduced by choosing microwave cooking in place of frying. Frying led to the formation of both the aminomethylimidazoquinoline and the carboline types of HAs.

Amines↗
PubMed1998

Cleidocranial dysplasia: a rare case associated with congenital hypothyroidism and severe neonatal hyperbilirubinemia.

Cleidocranial dysplasia is an autosomal dominant disorder affecting skeletal ossification and tooth development. This disorder can be rarely associated with blood, intestinal and vascular anomalies. There has been no case reported in previous literature that discusses this disorder in association with congenital hypothyroidism and severe neonatal hyperbilirubinemia. Herein, we report on a 4-year-old boy who in an outpatient clinic was diagnosed as having cleidocranial dysplasia, with defective ossification over bilateral hypoplastic clavicles, narrowed thoracic cage on chest x-ray and prominent wormian bones over the lambdoid sutures on skull x-ray. Physical examination revealed a 4-fb wide open anterial fontanel, frontal bossing and malalignment of teeth. He was a primpara with birth weight of 2350 gm and gestation age of 33 weeks. He had received blood exchange transfusion on the 4th postnatal day at Ping-Tong Christian Hospital because of severe neonatal hyperbilirubinemia. Congenital hypothyroidism was diagnosed on the 10th day. He was then treated with thyroxine and transferred to our hospital. Thyroid scan revealed diffusely decreased radioactivity in bilateral lobes of the thyroid gland. According to out clinic findings at his regular follow ups, with continued use of thyroxine supplement, he now has a normal thyroid function and has a body length of about 50 percentile.

Child, Preschool↗
PubMed1998

Molecular characterization of Chinese G6PD deficiency by using polymerase chain reaction/single strand conformation polymorphism.

Using the polymerase chain reaction/single strand conformation polymorphism (PCR/SSCP), we studied the molecular characterization of 97 (86 male and 11 female) glucose-6-phosphate dehydrogenase (G6PD) deficient Chinese newborn babies and infants in southern Taiwan. Movement shifts were clearly seen in exon 2, 5, 6 and 12, respectively. No movement shift was seen in exon 9. Mutation confirmations were followed by direct sequencing. Using this approach we identified the molecular defect in 90 of the 97 above samples. Our results show a total of seven variants, the most common being at nucleotide (nt) 1376 mutation G-->T 42.3% (41/97) and at nt 1388 mutation G-->A 34.0% (33/97). The other mutation sites were at nucleotide 95 A--G (5.2%), nucleotide 392 G-->T (4.1%), nucleotide 493 A-->G (3.1%) and two new variants with mutation at nucleotide 371 A-->G (2.1%) and nucleotide 519 C-->G (2.1%). Still 7.2% (7/97) remained unidentified. There was no significant difference in G6PD activity among the different mutations. Simple and fast, PCR/SSCP may be suitable for molecular screening for G6PD deficiency in Chinese and other people.

Female↗
PubMed1998

Dysfunctional uterine bleeding.

Abnormal uterine bleeding is a common, debilitating condition. Dysfunctional uterine bleeding (DUB) is the diagnosis given to women with abnormal uterine bleeding in whom no clear etiology can be identified. DUB has been observed in both ovulatory and anovulatory cycles. Medical treatments include nonsteroidal anti-inflammatory drugs, oral contraceptive pills, progestins, danazol (a synthetic androgen), GnRH agonists, and antifibrinolytic drugs. The drawback to medical therapy, in addition to side effects, is that the benefit lasts only while the patient takes the medication. Surgical options have concentrated mainly on endometrial ablation and hysterectomy, and it is unclear whether one is superior to the other in terms of long-term outcome and patient satisfaction. Newer and less invasive ablation techniques, such as thermal balloon ablation, offer more treatment alternatives.

Adolescent↗
PubMed1997

Pyruvate-extended amino acid derivatives as highly potent inhibitors of carboxyl-terminal peptide amidation.

Carboxyl-terminal amidation, a required post-translational modification for the bioactivation of many neuropeptides, entails sequential enzymatic action by peptidylglycine monooxygenase (PAM, EC 1.14.17.3) and peptidylamidoglycolate lyase (PGL, EC 4.3.2.5). The monooxygenase, PAM, first catalyzes conversion of a glycine-extended pro-peptide to the corresponding alpha-hydroxyglycine derivative, and the lyase, PGL, then catalyzes breakdown of this alpha-hydroxyglycine derivative to the amidated peptide plus glyoxylate. We now introduce the first potent inhibitors for peptidylamidoglycolate lyase. These inhibitors, which can be viewed as pyruvate-extended N-acetyl amino acids, constitute a novel class of compounds. They were designed to resemble likely transient species along the reaction pathway of PGL catalysis. A general synthetic procedure for preparation of pyruvate-extended N-acetyl amino acids or peptides is described. Since these compounds possess the 2,4-dioxo-carboxylate moiety, their solution tautomerization was investigated using both NMR and high performance liquid chromatography analyses. The results establish that freshly prepared solutions of N-Ac-Phe-pyruvate consist predominantly of the enol tautomer, which then slowly tautomerizes to the diketo form when left standing for several days in an aqueous medium; upon acidification, formation of the hydrate tautomer occurs. Kinetic experiments established that these novel compounds are highly potent, pure competitive inhibitors of PGL. Kinetic experiments with the ascorbate-dependent copper monooxygenases, PAM and dopamine-beta-monooxygenase, established that these compounds also bind competitively with respect to ascorbate; however, pyruvate-extended N-acyl-amino acid derivatives possessing hydrophobic side chains are much more potent inhibitors of PGL than of PAM. Selective targeting of N-Ac-Phe-pyruvate so as to inhibit the lyase, but not the monooxygenase, domain was demonstrated with the bifunctional amidating enzyme of Xenopus laevis. The availability of potent inhibitors of PGL should facilitate studies regarding the possible biological role of alpha-hydroxyglycine-extended peptides.

Amides↗
PubMed1997

[Relieving effect of sodium thiosulfate on transarterial chemotherapeutic emesis].

It was reported that sodium thiosulfate (STS) was contributed to antivomiting effect in 20 transarterial chemotherapic patients. The antitumor sensitivity of STS (< 500 micrograms/ml) adjuncting to the ADM, MMC, CDDP and other four agens (1 x PPC/ml) individually on two tumor cells studied by MTT test in vitro and no antitumor activity of adjuvant of STS were obviously obliterated (P > 0.05) except for CDDP clinically, to comparing the adjuncting effects of STS (iv. 30 min ahead) or metochlopramidum (im. 30 min ahead) to ADM, MMC and CDDP on HCC (40 cases), the degrees of vomiting in hepatoma patient after transcatheter arterial chemoem bolization with ADM, MMC and CDDP were statisticaly analysec. It have been proven that STS was contributed to the low incidence of vomiting and superior to metocloe pramidum, without worsening of the chemotherapy of HCC. It is worth futher studying adjuvant STS to other antitumor drugs and exploring potential application of chematherapy in cancer.

Adult↗