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Biomedical subjects

P M Yuen

Publications and source records attributed to P M Yuen.

At least 73 records · Page 4Linked to original sources
PubMed1998

A Chinese adolescent girl with Fechtner-like syndrome.

We describe a 15-y-old girl with Fechtner-like syndrome, who is the first Chinese reported to have this rare syndrome. She presented with left homonymous hemianopia and neuroimaging revealed haemorrhage in both parietal and occipital lobes. Peripheral blood smear showed macrothrombocytopenia and intracytoplasmic inclusion bodies inside leucocytes. Thrombocytopenia and proteinuria responded to intravenous immunoglobulin and pulsed methylprednisolone. This case illustrates that life-threatening haemorrhage can occur in patients with Fechtner syndrome. Although there was no effective treatment reported in the literature, high dose steroid and immunoglobulin seemed to be useful in our patient. Our patient also had nephritic-nephrotic syndrome with renal insufficiency, which is unusual in adolescent female patients.

Adolescent↗
PubMed1998

Is homozygous alpha-thalassaemia a lethal condition in the 1990s?

Two cases of homozygous alpha-thalassaemia who received active treatment in accordance with parental wishes are reported. One infant survived and the other, although successfully weaned off mechanical respiratory support, unexpectedly developed portal vein thrombosis and died. Homozygous alpha-thalassaemia, a condition previously considered to be universally fatal, and an indication for therapeutic abortion, is now potentially curable with advances in diagnostic technology and treatment. However, active management of these cases raises serious ethical questions and has major financial implications on the health-care system. Invasive prenatal and intensive postnatal interventions should remain experimental and cannot be recommended as routine clinical practice until the questions of long-term neurodevelopmental outcome, and the morbidity and mortality associated with bone-marrow transplantation have been fully addressed. As a result of advances in information technology, more and more parents of affected foetuses are likely to request active treatment.

Fatal Outcome↗
PubMed1998

Intraoperative laparoscopic sonography for improved preoperative sonographic pathologic characterization of adnexal masses.

This study compares the diagnostic accuracy of laparoscopic sonography and transvaginal sonography in the evaluation of adnexal masses. Fifty-eight women underwent transvaginal sonography, which showed 69 adnexal masses, and laparoscopic ultrasonography, which showed 68 adnexal lesions. Conventional gray-scale ultrasonography (using transvaginal sonography and laparoscopic ultrasonography) was performed with morphologic characterization of internal architecture, followed by color Doppler imaging with spectral Doppler analysis where possible. A specific diagnosis was obtained with transvaginal sonography and laparoscopic ultrasonography based on a combination of imaging features. The specific diagnosis obtained with each imaging modality was compared with the final histologic diagnosis as the gold standard in 57 patients with 68 adnexal masses who underwent cystectomy or oophorectomy. The ability of laparoscopic sonography to detect the contralateral ovary and any residual ovarian tissue in the presence of a mass was also compared with transvaginal sonography. The accuracy of laparoscopic ultrasonography in the characterization of adnexal masses was 83.8% and that of transvaginal sonography was 73.5% (P < 0.05). Laparoscopic sonography showed greater morphologic detail than that obtained with transvaginal sonography, allowed more precise and specific characterization of adnexal masses, and detected additional adnexal lesions not evident on preoperative transvaginal sonography. Laparoscopic ultrasonography showed the contralateral ovary in 86.2% of patients, compared with 81.0% using transvaginal sonography (P = 0.51). In addition, laparoscopic ultrasonography was able to demonstrate the presence of residual ovarian tissue in the side affected pathologically in 76.5% of patients compared with 59.4% using transvaginal sonography (P < 0.005). Laparoscopic sonography allows more precise morphologic characterization of internal architecture and histologic diagnosis of adnexal lesions, but it is as yet unable to increase the diagnostic accuracy of borderline or malignant lesions, possibly due to the small sample size. Laparoscopic sonography is superior to transvaginal sonography in the evaluation of residual ovarian tissue in the side affected pathologically, which may help in surgical planning between cystectomy and oophorectomy, and also in the identification of the contralateral ovary, which may potentially increase the detection of bilateral pathologic conditions.

Adnexal Diseases↗
PubMed1998

Routine analysis of plasma busulfan by gas chromatography-mass fragmentography.

Busulfan (BU) is a widely used alkylating agent for antineoplastic therapy and marrow ablation in preparation for bone marrow transplantation (BMT). High-dose BU often leads to successful preparation and low relapse but is associated with veno-occlusive disease of liver. We established a protocol to determine postdosage plasma BU concentrations by gas chromatography-mass fragmentography in an attempt to relate clinical outcome to plasma BU concentrations. We used nonisotopic pusulfan as the internal standard. After extraction into ethyl acetate, BU and pusulfan were iodinated into 1, 4-diiodobutane and 1,5-diiodopentane, respectively. Gas chromatography-mass spectrometry (GC-MS) analysis was carried out on an Hewlett-Packard (HP) 5890II gas chromatograph with a 30-m 100% methyl silicon narrow bore, fused-silica capillary column interfaced with an HP 5970A mass spectrometer. Helium was the carrier gas. The sample molecules were identified by total ion monitoring and quantified by selective ion monitoring of m/z 183 and 197. The calibration curve was linear to 4 mg/L. The limit of quantification was 0.04 mg/L, and the analytical recovery was approximately 97%. The within-day and between-day imprecision (CV) was <6% and 9%, respectively. In a preliminary study of 12 children, the BU areas under the BU-time curve were 616-949 micromol. min/L after the first dose and 793-1143 micromol. min/L after the fifth dose. We conclude that the GC-MS procedure is suitable for routine analysis of plasma BU.

Adolescent↗
PubMed1997

A randomized prospective study of laparoscopy and laparotomy in the management of benign ovarian masses.

OBJECTIVE: Our purpose was to compare the results of laparoscopy with laparotomy in the management of ovarian masses not suspected to be malignant. STUDY DESIGN: In a prospective randomized study 102 patients requiring surgical management of ovarian masses were randomly assigned to laparoscopy (52) or laparotomy (50) in a teaching hospital from July 1994 to September 1995. Inclusion criteria was tumor not suspected to be malignant with a diameter of < or = 10 cm as measured by ultrasonography. All operations were performed by trainees under the supervision of an experienced surgeon. Statistical analysis included t tests and chi2 tests. RESULTS: There were no differences in demographic characteristics between the two groups nor any difference in the size of ovarian masses, adnexal adhesion score, or frequency of bilateral disease. All the ovarian masses were benign. Endometriotic cysts and dermoid cysts were the most common disorder in the two groups. Cystectomy was performed in > 70% of cases in each group. Operating time was not increased with the laparoscopic approach, and the frequency of inadvertent rupture of the ovarian masses was just as high as in laparotomy. The laparoscopic approach was associated with a significant reduction in operative morbidity (odds ratio 0.34, 95% confidence interval 0.13 to 0.88), postoperative pain and analgesic requirement, hospital stay, and recovery period. Patients in general were satisfied with the operation, but significantly more patients were satisfied with the laparoscopy scar. CONCLUSION: Operative laparoscopy should replace laparotomy in the management of benign ovarian masses.

Adult↗
PubMed1997

Transfusion-related immunomodulation in Chinese children with thalassaemia.

BACKGROUND AND OBJECTIVES: Multiple transfusions can induce immunomodulation. This study was carried out to investigate the immunological status of 50 transfusion-dependent children with beta-thalassaemia, taking into account that lymphocyte characteristics are affected by sex, age and race. We paid particular attention to the influence of transfusion and serum ferritin on the lymphocyte subsets which may be affected by the exposure to foreign antigens. MATERIALS AND METHODS: By multicolour immunofluorescent analysis using flow cytometry, we determined lymphocyte characteristics with regard to major subsets (T lymphocytes, B lymphocytes and NK cells), activation (membrane IL-2 receptor CD25, HLA-D) and memory/naive T cells (CD45RO/CD45RA). Data from 51 age- and sex-balanced children served as controls. RESULTS: The normal Chinese children had higher NK levels than the beta-thalassaemia children. The levels of CD25 and HLA-D indicated a broad-based increase in activation status. Memory T cells were also increased when compared with their normal counterparts. We found additional and more marked alterations in the lymphocyte subsets of those who had received over 100 transfusions. While levels of NK cells were inversely correlated with the number of transfusions, CD25+ cells increased with transfusions. CONCLUSION: Many multitransfused beta-thalassaemia children have altered levels of lymphocyte subsets compared with normals. What remains to be investigated is the long-term consequence of possessing low NK and non-MHC-restricted T cells (CD3+CD56+CD16+) and a high activation status in terms of resistance of infections and development of malignancy.

Adjuvants, Immunologic↗
PubMed1997

Laparoscopic management of adnexal mass during pregnancy.

BACKGROUND: To assess the use of laparoscopy in the management of persistent adnexal mass during the second trimester of pregnancy. SUBJECTS: Six consecutive pregnant women undergoing laparoscopic surgery for persistent adnexal masses in the second trimester. RESULTS: Laparoscopic removal of an adnexal mass was successfully performed in all patients. The median operating time was 37.5 minutes. There were no intra- and post-operative complications. Tocolytic therapy was not required and no patients developed uterine contractions. All patients delivered normal infants vaginally at term without complications. CONCLUSION: With attention to the surgical technique, laparoscopic removal of persistent adnexal mass during the second trimester of pregnancy is safe and carries the same benefits over laparotomy as in non-pregnant women.

Adult↗
PubMed1997

A review of laparoscopy and laparotomy in the management of tubal pregnancy.

A retrospective review was performed of all women who had undergone operation for a tubal pregnancy at the Prince of Wales Hospital, Hong Kong, from November 1992 to March 1994. One hundred and five patients were included---61 were managed by laparoscopy and 44 by laparotomy. There were no differences in age, parity, gestational age, frequency of previous ectopic pregnancy, or laparotomy between the two groups. Sixty per cent of patients in the laparotomy group had a diagnostic laparoscopy prior to the laparotomy. The laparoscopy group had a lower incidence of haemoperitoneum (45.9% vs 75.0%, P<0.05). There was no difference in the mean operating time. The laparoscopic approach was associated with a significant reduction in: intra-operative blood loss (46.7plus minus76.8 mL vs 213.4plus minus149.3 mL. P<0.001), post-operative analgesia requirement (odds ratio 0.08, 95% CI, 0.02-0.32), post-operative morbidity (odds ratio 0.27, 95% CI, 0.12-0.58), length of hospital stay (2.9plus minus2.2 days vs 5.1plus minus1.2days, P<0.001) and recuperation period (11.0plus minus9.3days vs 21.7plus minus8.5 days, P<0.001). Operative laparoscopy has the advantage of combining diagnostic and therapeutic procedures in a single operation, and is a better approach than laparotomy in the management of tubal pregnancy.

Journal Article↗
PubMed1996

Cervical ripening before induction of labour in patients with an unfavourable cervix: a comparative randomized study of the Atad Ripener Device, prostaglandin E2 vaginal pessary, and prostaglandin E2 intracervical gel.

One hundred and nineteen women with singleton pregnancy and cephalic presentation requiring induction of labour in the presence of an unfavourable cervix (Bishop score < or = 4) were studied. Five patients were excluded because of failure to comply with the protocol. Cervical ripening was carried out using 3 different methods; 36 used the Atad Ripener Device, 39 received 0.5 mg PGE2 intracervical gel and 39 received at least one 3 mg PGE2 intravaginal pessary. There were no differences in the demographic characteristics and the indications for induction. Five patients developed complications during the ripening period necessitating intervention; 3 required emergency Caesarean section and 2 delivered vaginally. Although statistically there were no differences among the 3 methods of cervical ripening, the power of the study is probably not large enough to show the differences. The PGE2 pessary appears to be more effective with 68% of patients either going into labour during cervical ripening or succeeding in the cervical ripening compared to around 50% in the Atad and PGE2 gel groups. The vaginal delivery rate was 87.2% in the pessary group compared to 72.2% in the Atad group and 84.6% in the gel group. The duration of labour was also shorter in the pessary group with 73.5% delivered within 24 hours compared to 57.7% in the Atad group and 57.6% in the gel group. Although the results of the Atad device seem to be inferior, the risk of uterine hyperstimulation from the use of the device is probably lower than that of the PGE2 and may therefore be preferable in women with fetuses at high risk of fetal hypoxia.

Adult↗
PubMed1996

Is laparoscopically-assisted vaginal hysterectomy associated with low operative morbidity?

Seventy-one consecutive patients undergoing laparoscopically-assisted vaginal hysterectomy were prospectively evaluated with particular emphasis on the operative morbidity. Bipolar desiccation was the mainstay for haemostasis. Fibroids accounted for two-thirds of the uterine pathology and the average uterine weight was 238.0 g (SD 134.6). Mean operating time was 126.3 minutes (SD 36.9) and decreased with experience despite the progressive increase in uterine weight. The mean blood loss was 432 mL (SD 288) with a mean haemoglobin change of 2.3 g/dL (SD 1.5). Intraoperative complications occurred in 5 patients (7.0%), 2 with inferior epigastric artery injuries and 3 serosal bladder injuries. Postoperative complications occurred in 45 patients (63.4%). Febrile morbidity was the major complication and occurred some 50% of patients, 45% of whom had no underlying cause identified. Vault haematoma was the second most common complication and occurred in 31.0%. The mean hospital stay was 5.4 days (SD 2.7) and the readmission rate was 10%. Our results of laparoscopically-assisted vaginal hysterectomy did not conform with the benefits of reduced blood loss, shorter hospital stay and reduced postoperative complications reported in the literature. The true complication rate of laparoscopically-assisted vaginal hysterectomy should be carefully assessed before this can be considered as the approach of choice to hysterectomy.

Adult↗
PubMed1996

Unexpected ovarian malignancy diagnosed after laparoscopic surgery.

The main concerns for laparoscopic management of ovarian masses are unexpected malignancy and the spillage of the cyst content. Careful preoperative evaluation is important in proper patient selection. We report a case of unexpected ovarian malignancy managed by operative laparoscopy in a 29-year-old woman. The role of ultrasonographic and laparoscopic assessment and their limitations are discussed. The potential role of intraoperative laparoscopic ultrasonographic assessment of the ovarian masses is proposed.

Adult↗
PubMed1996

Paecilomyces varioti fungemia in a bone marrow transplant patient.

Paecilomyces varioti, a fungus resembling penicillium spp, has been described in conjunction with impaired host defence or foreign body implants. We report a case of Paecilomyces varioti catheter-related fungemia that occurred during neutropenia in an allogeneic BMT patient receiving antifungal prophylaxis with fluconazole. Successful treatment was achieved by removal of central venous catheter, intravenous amphotericin B and oral itraconazole.

Bone Marrow Transplantation↗
PubMed1996

A more immunosuppressive pre-transplant conditioning may be required for Chinese patients with thalassaemia.

Bone marrow transplantation was performed on 14 Chinese patients with transfusion dependent thalassaemia major (n = 13) and haemoglobin H disease (n = 1). The donors were HLA identical siblings. The source of haematopoietic stem cells were from bone marrow (n = 13) and umbilical cord blood (n = 1). The pre-transplant conditioning regimens were (1) busulphan 14 mg/kg and cyclophosphamide 200 mg/kg in two patients; (2) busulphan 16 mg/kg, cyclophosphamide 200 mg/kg and anti-thymocyte globulin 110 mg/kg in five patients; (3) busulphan 16 mg/kg, cyclophosphamide 150 mg/kg and anti-thymocyte globulin 110 mg/kg in seven patients. Graft-versus-host disease prophylaxis was cyclosporin A and methotrexate. All patients engrafted and achieved stable haematopoiesis except the one who underwent the umbilical cord blood transplant, who had autologous marrow recovery. One patient who had stable engraftment rejected the marrow graft and developed aplastic anaemia 4 months after BMT. This patient had a second BMT but rejection recurred again. She eventually died of septicaemia. The other 12 patients were transfusion independent and disease free. The majority have gone back to school or work. Disease-free and actuarial survival probability were 85 and 93%, respectively with a median follow-up time of 30 months (13 to 42 months). Our data suggest that BMT from HLA identical siblings for transfusion dependent thalassaemia gives a high chance of cure with acceptable mortality and morbidity, and that a more immunosuppressive pre-transplant conditioning schedule may be required to prevent rejection.

Adolescent↗