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Biomedical subjects

Y C Chu

Publications and source records attributed to Y C Chu.

At least 37 records · Page 2Linked to original sources
PubMed2000

Autologous bone marrow transplantation for patients with acute myeloid leukaemia: prospective follow-up study.

OBJECTIVE: To study the use of autologous bone marrow transplantation to treat acute myeloid leukaemia when complete remission had been achieved and when no human leukocyte antigen matched related donor was available. DESIGN: Prospective follow-up study. SETTING: Government hospital, Hong Kong. PATIENTS: Eight patients (median age, 34 years [range, 16-45 years]) with acute myeloid leukaemia in whom complete remission had been achieved. INTERVENTION: Conditioning regimen of carmustine, amsacrine, etoposide VP-16, cytarabine, and infusion of unpurged marrow. MAIN OUTCOME MEASURES: Median time taken to reach neutrophil and platelet counts of > or =0.5 x 10(9) /L and > or = x 10(9) /L, respectively; mortality and relapse rates; and follow-up regimens used. RESULTS: Engraftment was successfully achieved in all patients and there were no early procedure-related mortalities. The median times required to reach a neutrophil count of > or =0.5 x 10(9) /L and a platelet count of > or =20 x 10(9) /L were 30 days (range, 18-36 days) and 38 days (range, 15-53 days), respectively. The median duration of hospital stay was 37 days (range, 25-43 days). Two patients died of a relapse of leukaemia at 6 and 9 months post-transplantation. Two patients experienced relapses: one at 8 months post-transplantation, for which conventional chemotherapy was restarted, and one at 18 months; treatment with all-trans-retinoic acid and conventional chemotherapy achieved a third complete remission in the latter patient, who had acute promyelocytic leukaemia. Continuous remission has been achieved in four of the eight patients after a median follow-up duration of 26 months (range, 6-43 months). CONCLUSION: Autologous bone marrow transplantation is an acceptable treatment for patients with acute myeloid leukaemia who lack a human leukocyte antigen-matched related donor.

Acute Disease↗
PubMed2000

[Effect of jiaweiyiguanjian decoction on hypothalamus-pituitary-thyroid gland (HPT) in rat model with Yin-deficiency of liver and kidney induced by slow irritation].

OBJECTIVE: To explore the mechanism of Jiaweiyiguanjian decoction in nourishing the liver and kidney. METHOD: A rat model with Yin-deficiency of liver and kidney was made by way of slow irritation. Thyrotropin-releasing-hormone(TRH) of thyron and blood, TSH of pituitary and blood, thyroxine, 3,5,3',5-tetraiodothyronine(FT4) and 3,3',5-traiodothyronine(FT4), 3,3',5-traiodothyronine(rT3) were used as indexes to study the effect of the decoction on HPT. RESULT: The TRH Secretion from hypothalamus increased (P < 0.05), TSH of pituitary and blood reduced(P < 0.05), FT3 and FT4 of blood decreased at the same time and rT3 of blood, increased. The indexes of the treatment group were found almost the same as the those of the normal control group. CONCLUSION: Jiaweiyiguanjian Decoction could adjust HPT.

Animals↗
PubMed1999

Gastric malignant stromal tumor with long stalk impacted into duodenum.

Most GIST have traditionally been classified as submucosal origin by upper gastrointestinal series (UGIS) or endoscopy. However, we experienced a gastrointestinal mesenchymal origin tumor expressed by polypoid mass with a long stalk. The gastric outlet was obstructed by the polypoid mass on the duodenum. The microscopic findings of the resected mass showed a stromal cell component by immunohistochemical stain. We experienced gastric stromal tumor found as a polypoid mass with long stalk which was easily detected by endoscopy. It would not have been suspected as a stromal tumor as a result of endoscopic findings only.

Aged↗
PubMed1999

Comparison of recovery characteristics of sevoflurane and halothane for outpatient surgery in infants.

BACKGROUND: Sevoflurane, a newly approved potent inhaled anesthetic in Taiwan, provides rapid emergence from anesthesia in adults and children. Clinically, it is difficult to accurately assess the rate of recovery from anesthesia in infants. This study was designed to compare the emergence characteristics of halothane with those of sevoflurane having recourse to a respiratory agent monitor in infants undergoing outpatient surgery. METHODS: Forty infants of ASA class I, scheduled for day-case urologic surgery were studied. Patients were randomly allocated to two groups of 20. Sevoflurane or halothane was used as the inhaled anesthetic. Toward the end of surgery, sevoflurane or halothane was turned off. The concentrations of exhaled sevoflurane or halothane were read every minute after its discontinuation until extubation. The decay curve of the exhaled concentration of either agent was recorded minute by minute for 10 minutes. The time intervals from discontinuation of the inhalation agent to spontaneous movement and tracheal extubation were recorded. Untoward side-effects during emergence were also compared. RESULTS: Sevoflurane was eliminated faster than halothane. Based on the decay curves of the exhaled concentrations of the two agents, the time constant for halothane was 2.59 minutes and that for sevoflurane was only 1.43 minutes. The time from discontinuation of agent to extubation was also shorter for sevoflurane. Postoperative restlessness or agitation occurred more frequently in infants who received sevoflurane, although the difference was of no statistical significance. CONCLUSIONS: Sevoflurane is superior to halothane for rapid elimination in infant outpatient surgery as gauged by observation of end-tidal concentration elimination curves recorded with a respiratory agent monitor. No other postoperative side-effect was evident in sevoflurane anesthesia.

Ambulatory Surgical Procedures↗
PubMed1998

Splenic lymphoma with villous lymphocytes showing del(7) and inv(10).

A 49-year-old woman presented with splenic lymphoma with villous lymphocytes (SLVL) that showed a clonal abnormality of del(7)(q22q32) in addition to inv(10)(p13q23), the latter being a previously undescribed abnormality in chronic lymphoproliferative disorders. A review of the literature on cytogenetic abnormalities of SLVL indicates that del(7q) is strongly associated with SLVL and may be important in the pathogenesis of this disorder.

Chromosome Deletion↗
PubMed1998

Mini-proinsulin and mini-IGF-I: homologous protein sequences encoding non-homologous structures.

Protein minimization highlights essential determinants of structure and function. Minimal models of proinsulin and insulin-like growth factor I contain homologous A and B domains as single-chain analogues. Such models (designated mini-proinsulin and mini-IGF-I) have attracted wide interest due to their native foldability but complete absence of biological activity. The crystal structure of mini-proinsulin, determined as a T3R3 hexamer, is similar to that of the native insulin hexamer. Here, we describe the solution structure of a monomeric mini-proinsulin under physiologic conditions and compare this structure to that of the corresponding two-chain analogue. The two proteins each contain substitutions in the B-chain (HisB10-->Asp and ProB28-->Asp) designed to destabilize self-association by electrostatic repulsion; the proteins differ by the presence or absence of a peptide bond between LysB29 and GlyA1. The structures are essentially identical, resembling in each case the T-state crystallographic protomer. Differences are observed near the site of cross-linking: the adjoining A1-A8 alpha-helix (variable among crystal structures) is less well-ordered in mini-proinsulin than in the two-chain variant. The single-chain analogue is not completely inactive: its affinity for the insulin receptor is 1500-fold lower than that of the two-chain analogue. Moreover, at saturating concentrations mini-proinsulin retains the ability to stimulate lipogenesis in adipocytes (native biological potency). These results suggest that a change in the conformation of insulin, as tethered by the B29-A1 peptide bond, optimizes affinity but is not integral to the mechanism of transmembrane signaling. Surprisingly, the tertiary structure of mini-proinsulin differs from that of mini-IGF-I (main-chain rms deviation 4.5 A) despite strict conservation of non-polar residues in their respective hydrophobic cores (side-chain rms deviation 4.9 A). Three-dimensional profile scores suggest that the two structures each provide acceptable templates for threading of insulin-like sequences. Mini-proinsulin and mini-IGF-I thus provide examples of homologous protein sequences encoding non-homologous structures.

Amino Acid Sequence↗
PubMed1998

Acute myeloid leukemia with a novel (7;11)(q36;q13) translocation.

A 79-year-old female presented with acute myeloblastic leukemia without maturation. Cytogenetic studies showed a previously undescribed abnormality of t(7;11)(q36;q13). The significance of the involvement of 11q13 in the pathogenesis of myeloid leukemia is discussed.

Aged↗
PubMed1998

Abnormal erythropoiesis in erythroleukemia: a fluorescence in situ hybridization study.

Erythroleukemia is an uncommon leukemia with heterogeneous morphologic and karyotypic features. Some cases might actually represent acute myeloid leukemia with a reactive erythroid hyperplasia. In this report, we described a 68-year-old woman with erythroleukemia and monosomy 7 and showed by fluorescence in situ hybridization that both myeloid and erythroid lineage were clonally involved and that both normal and abnormal erythroid populations coexisted, albeit indistinguishable by morphological examination. These findings may account for the variation in the erythropoietic activity observed in the clinical course of erythroleukemia.

Aged↗
PubMed1998

Effect of BL-10 (tianzhu), BL-11 (dazhu) and GB-34 (yanglinquan) acuplaster for prevention of vomiting after strabismus surgery in children.

BACKGROUND: Stimulation of P6 (Neiguan) acupoint can prevent nausea and vomiting in adults. However, there is no antiemetic effect in children undergoing strabismus surgery. The effect of P6 may act only on hollow organs; in contrast, BL-10 (Tianzhu), BL-11 (Dazhu) and GB-34 (Yanglinquan) are more related to the meridians of the eye. Therefore these three more relevant acupoints, BL-10, BL-11 and GB-34 were stimulated to evaluate the antiemetic effect in children undergoing strabismus surgery. METHODS: Sixty-five children, ASA physical status I, between 3 and 14 years of age, were randomly divided into two groups as follows: placebo group (n = 31) and acuplaster group (n = 34). Bilateral acupressure using the Vital Point Needleless Acuplaster (Koa, Japan) was applied to BL-10, BL-11 and GB-34 points the night before surgery. Anesthesia was induced and maintained with halothane and nitrous oxide in oxygen. Postoperative emesis was assessed at early (at PACU) and late (at ward) phases, and was recorded by an investigator blind to the treatment characteristics. RESULTS: In the early emesis phase, the incidence of vomiting was 35.5% for placebo group, compared with 14.7% for acuplaster group. In the late emesis phase, acuplaster patients had a significantly lower incidence of vomiting (23.5% vs. 58.1% in placebo patients, p < 0.05). The overall postoperative vomiting incidence in the acuplaster patients in a 24 h period which was significantly decreased was 29.4% as opposed 64.5% in the placebo group (p < 0.05). CONCLUSIONS: The results demonstrated that prophylactic use of bilateral noninvasive acuplaster on the BL-10, BL-11, and GB-34 acupoints significantly reduces vomiting after strabismus correction. The mechanism may be dispersal of these three acupoints, thus diminishing the parasympathetic stimulation resulting from surgical traction of eye muscles.

Acupressure↗
PubMed1998

The neuromuscular effects of mivacurium in adults with priming technique during nitrous oxide-fentanyl anesthesia: a randomized comparative study with succinylcholine.

BACKGROUND: We investigated the neuromuscular effects of equipotent dose (3 x ED90) of mivacurium either given as a single bolus or under the influence of priming technique, comparing with that of succinylcholine in adults undergoing elective surgery during nitrous oxide-narcotic anesthesia. METHODS: Sixty ASA class I patients of either sex with age between 16 to 49 years were randomly assigned to 3 groups for a trial of mivacurium under nitrous oxide-narcotic anesthesia. Group I (non-priming group, n = 20) received mivacurium 0.25 mg/kg straight as a single intubating dose; Group II (priming group, n = 20) received an intubating dose of 0.225 mg/kg mivacurium which was preceded by 0.025 mg/kg 3 min earlier; and Group III received an intubating bolus of succinylcholine 1 mg/kg. Thenar electromyogram response to supramaximal train-of-four stimulation of the ulnar nerve at 12-s intervals was used to determine neuromuscular blockade. Blood pressure and heart rate were recorded before and at 1-min interval for 3 min after injection of drugs. Data were presented as mean +/- standard deviation. P value < 0.05 was considered statistically significant. RESULTS: The onset time of mivacurium was accelerated by priming procedure in comparison with the nonpriming technique (2.0 min vs. 2.7 min), but it was much slower than that of succinylcholine (0.8 min). The priming procedure did not influence the duration of action or recovery. Side effects of mivacurium, such as cutaneous flushing and hypotension, were minimal at this dose in our patients. CONCLUSIONS: Priming technique (with 10% of the total dose as the priming dose, and 3 min as the priming interval) can hasten the onset of mivacurium in adults during nitrous oxide-narcotic anesthesia without influencing the duration of action and recovery time.

Adolescent↗
PubMed1997

Improved treatment outcome in adult acute lymphoblastic leukemia using the intensive German protocol, a preliminary report.

Thirty-nine consecutive patients with acute lymphoblastic leukemia were treated with an intensive chemotherapy protocol. There were 23 males and 16 females with a median age of 37 years (range: 15-65). Eighteen patients had common ALL, seven had pre-B ALL, three early-precursor B ALL, seven T-ALL and four had aberrant expression of myeloid antigens (c-ALL in three and pre-B ALL in one). The median initial leukocyte count was 11.8 x 10(9)/l (range: 0.65-295). Cytogenetic result of the marrow was available in 16 of 39 patients (41 per cent) and showed Philadelphia positivity in six, a normal result in six and one each of t(4,11), t(1,19), hyperdiploidy and del 12p. Hepatosplenomegaly was present in about 20 per cent of the patients. L-Asparaginase-related hepatic toxicity was the commonest toxicity (48.7 per cent) during phase I of induction. Prolonged pancytopenia and hypoplastic death were common during phase II. With the use of growth factors during the neutropenic period of phase II induction, the rate of hypoplastic death was reduced from 40 per cent to 3 per cent. Common causes of treatment failure included early hypoplastic death (27.8 per cent) and leukemia relapses (50 per cent) while primary refractory leukemia, hepatic failure and perforated peptic ulcer contributed to 11.1, 5.5 and 5.5 per cent of the other deaths. A high complete remission (CR) rate (87.4 per cent) was achieved after phase I induction. The median event-free survival (EFS) was 8 months and the 3-year event-free survival was 43 per cent. This result compared favourably to the other regimens previously employed in our institution. In conclusion, satisfactory survival can be achieved with this intensive regimen. Good supportive care was however, essential to minimize toxicities.

Adolescent↗
PubMed1997

Dedifferentiated liposarcoma: a clinicopathological analysis of 155 cases with a proposal for an expanded definition of dedifferentiation.

We studied 155 cases of dedifferentiated liposarcoma to define its clinicopathologic features and behavior, in particular how the extent and grade of dedifferentiation affected outcome. Tumors occurred in late adult life (median, 61.5 years: range, 21-92 years), most commonly in the retroperitoneum (106 cases), extremities and trunk (32 cases), and scrotum/spermatic cord (13 cases). The majority of dedifferentiated liposarcomas presented as de novo lesions, whereas the remainder developed as a late complication of a preexisting well-differentiated liposarcoma after an average interval of 7.7 years. At the time of presentation, most of the dedifferentiated liposarcomas displayed extensive areas of high-grade dedifferentiation resembling malignant fibrous histiocytoma or high-grade fibrosarcoma, whereas a minority contained only areas of low-grade dedifferentiation resembling fibromatosis or well-differentiated fibrosarcoma. Divergent myosarcomatous or osteosarcomatous differentiation was observed focally in six cases. The behavior of dedifferentiated liposarcomas was that of a high-grade sarcoma with a local recurrence rate of 41%, a metastatic rate of 17%, and disease-related mortality of 28%. The most important prognostic factor was location in that retroperitoneal tumors had significantly worse survival than those in other sites. Tumors were divided into those having less than or those with more than 25% dedifferentiation, and dedifferentiated zones were classified into low grade or high grade. Neither low-grade dedifferentiation nor a low percentage of dedifferentiation was associated with an improved outcome for the tumors examined in this study; however, in no cases was the absolute size of the dedifferentiated focus <2 cm. Therefore, this study did not determine a minimum, or threshold, amount of dedifferentiation below which outcome was more favorable. The behavior of liposarcomas in which the dedifferentiated component was entirely low grade was more similar to that of traditional dedifferentiated liposarcoma than to that of well-dedifferentiated liposarcoma. Our study supports the expansion of the definition of dedifferentiated liposarcoma to include tumors with low-grade dedifferentiation and also suggests that low-grade dedifferentiation represents a precursor lesion of high-grade dedifferentiation.

Adult↗
PubMed1997

Priming technique accelerates the onset time of mivacurium in children during halothane anesthesia.

BACKGROUND: Mivacurium is considered a relaxant suitable for tracheal intubation in children due to its rapid onset. We compared the neuromuscular effects of mivacurium, with and without priming, in children undergoing elective surgery during halothane anesthesia. METHODS: Forty pediatric patients (2-10 yr, ASA class I) were randomly into 2 groups and studied under halothane anesthesia. The non-priming group (n = 20) received mivacurium 0.25 mg/kg, and the priming group (n = 20) received a priming dose of mivacurium 0.025 mg/kg, followed by an intubating dose of 0.225 mg/kg 3 min later. Thenar Electromyogram responsive to supramaximal train-of-four stimulation of the ulnar nerve at 12 s intervals was used as neuromuscular monitoring. RESULTS: The onset time in the priming group was significantly faster than in the non-priming group (1.04 min vs. 1.7 min). The mean time from injection of intubating dose to spontaneous recovery to 25%, 50% and 75% twitch were not influenced by priming technique. Side effects, such as cutaneous flushing and hypotension, were unremarkable at this dose in children. CONCLUSIONS: Priming technique can significantly accelerates the onset of mivacurium in the pediatric patients under halothane anesthesia.

Anesthesia, Inhalation↗
PubMed1996

Mapping the functional surface of insulin by design: structure and function of a novel A-chain analogue.

Functional surfaces of a protein are often mapped by combination of X-ray crystallography and mutagenesis. Such studies of insulin have yielded paradoxical results, suggesting that the native state is inactive and reorganizes on receptor binding. Of particular interest is the N-terminal alpha-helix of the A-chain. Does this segment function as an alpha-helix or reorganize as recently proposed in a prohormone-convertase complex? To correlate structure and function, we describe a mapping strategy based on protein design. The solution structure of an engineered monomer ([AspB10, LysB28, ProB29]-human insulin) is determined at neutral pH as a template for synthesis of a novel A-chain analogue. Designed by analogy to a protein-folding intermediate, the analogue lacks the A6-A11 disulphide bridge; the cysteine residues are replaced by serine. Its solution structure is remarkable for segmental unfolding of the N-terminal A-chain alpha-helix (A1 to A8) in an otherwise native subdomain. The structure demonstrates that the overall orientation of the A and B chains is consistent with reorganization of the A-chain's N-terminal segment. Nevertheless, the analogue's low biological activity suggests that this segment, a site of clinical mutation causing diabetes mellitus, functions as a preformed recognition alpha-helix.

Amino Acid Sequence↗
PubMed1996

All-trans retinoic acid (ATRA) in the treatment of acute promyelocytic leukemia (APL).

Acute promyelocytic leukemia is characterized by the reciprocal translocation of chromosomes 15 and 17. All-trans retinoic acid (ATRA) efficiently induces differentiation of the abnormal promyelocytes. In this study, we had used ATRA as the primary induction therapy for 17 newly diagnosed patients, and as the salvage therapy for 11 patients who relapsed from or were resistant to chemotherapy. All patients received subsequent consolidation chemotherapy. Complete remission (CR) rate, early death rate (within 28 days of diagnosis) were then compared to an historical control of 50 APL patients treated with combination chemotherapy; and event-free survival of the 17 newly diagnosed patients was compared to the historical control. In the ATRA group, 26 of the 28 patients (93 per cent) attained complete remission. Two of 28 (7 per cent) died within 28 days of ATRA therapy. There was no case of primary resistance to ATRA. Combination chemotherapy was added to ATRA in five patients due to rapidly increasing leucocyte count. There was one case of retinoic acid syndrome which resolved with steroid. When compared to the 50 cases of historical control, there is significant improvement in the overall CR rate (92 per cent versus 59 per cent, p = 0.001) and a significant reduction in the early mortality rate (7 per cent versus 41 per cent, p = 0.001). Moreover, when the survival result of the 17 newly diagnosed patients were compared with the control, there is a significant improvement in the projected EFS at 3 years (64 per cent versus 25 per cent, p = 0.007). In conclusion, ATRA was shown to improve the CR rate, reduce induction mortality and significantly prolong the event-free survival.

Adolescent↗
PubMed1996

Terbutaline inhalation suppresses fentanyl-induced coughing.

PURPOSE: To study the suppressive effect of inhalation of a selective beta 2-adrenergic bronchodilator terbutaline, and the effect of an intravenous anticholinergic, atropine, on fentanyl-induced coughing. METHODS: We studied 131 ASA class I patients, aged 16-45 yr, scheduled for elective surgery, randomized into four groups. Fifteen minutes before bolus fentanyl (5 micrograms.kg-1, iv), patients inhaled either normal saline (4 ml; Group I, n = 30) or terbutaline (5 mg in 2 ml normal saline; Group 2, n = 34) via a jet nebulizer. After inhalation of normal saline, patients in Group 3 (n = 32) received sterile water iv instead of fentanyl. Patients in Group 4 (n = 35) were pretreated with atropine (0.01 mg.kg-1, iv) 10 min before iv fentanyl bolus. The onset, frequency and intensity of cough were observed immediately by an anaesthetist blinded to the study. RESULTS: The cough frequency was higher in Groups I (43%) and 4 (46%) than in Groups 2 (3%) and 3 (0%) (P < 0.05). The onset time and intensity of cough showed no difference among groups. No truncal rigidity was observed in patients receiving fentanyl bolus iv. The blood pressure, heart rate, and peripheral oxygen saturation did not change in Groups 1, 2, and 3, while patients in Group 4 showed an increase in heart rate (25.5 +/- 15.2%). CONCLUSIONS: The inhalation of a selective beta 2-adrenergic bronchodilator, terbutaline, effectively inhibited fentanyl-induced cough, whereas atropine, an antimuscarinic vagolytic, had no efficacy. Our results suggest that bronchoconstriction may underlie the mechanism on fentanyl-induced cough.

Administration, Inhalation↗
PubMed1996

Pure red cell aplasia: clinical features and treatment results in 16 cases.

Pure red cell aplasia (PRCA) is a rare hematological disease characterized by selective marrow erythroid aplasia. We report the clinical features and treatment results of 16 Chinese patients with PRCA. Nine (56%) cases were not associated with any underlying disorders and were considered idiopathic, while seven patients (44%) had associated diseases, three involving the thymus, two with T large granular lymphocyte leukemia (T-LGLL), and one each with Stevens-Johnson syndrome and acute hepatitis A. Conventional-dose corticosteroid therapy resulted in complete remission in three of 13 patients. Cyclosporin A was used in six patients. There were three complete and one partial remissions. High-dose methylprednisolone was ineffective in four patients who failed conventional-dose corticosteroids but achieved complete remission in one patient with thymoma who did not respond to thymectomy. Antithymocyte globulin was used in four patients, resulting in partial remission in only one patient with concomitant T-LGLL. Intravenous gamma globulin and danazol were ineffective in three patients. Thymectomy was performed in two patients, with one patient remitting. This is the largest series of PRCA reported in an oriental population. Our results indicate that treatment of PRCA may still be problematic and better therapeutic strategy will have to be defined.

Adrenal Cortex Hormones↗