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Biomedical subjects

C Y Lo

Publications and source records attributed to C Y Lo.

At least 55 records · Page 3Linked to original sources
PubMed1999

Surgical implications of underestimation of adrenal tumour size by computed tomography.

BACKGROUND: Size of adrenal mass is an important consideration during adrenal surgery, with regard to the choice of surgical approach and management of adrenaloma. The aim of the present study was to evaluate the precision of preoperative computed tomography (CT) on the size estimation of adrenal lesions and to review its potential implications on surgical decision making. METHODS: Records of 110 patients who underwent adrenalectomy for various adrenal pathologies from 1981 to 1997 were reviewed retrospectively. Patients (n = 92) who had documented dimensions of adrenal mass by both preoperative CT and pathological examination were selected for analysis. RESULTS: CT overall underestimated the actual size of adrenal lesions by 16 per cent compared with measurement of resected specimens (mean 3.1 versus 3.6 cm; P < 0.001). There was a significant underestimation of the actual size of adrenal lesions measuring less than 6 cm by CT but not for lesions larger than 6.0 cm. Phaeochromocytoma (n = 17) was the only pathological condition consistently underestimated by CT. CONCLUSION: Conventional CT overall underestimates the real size of adrenal lesions, in particular phaeochromocytoma and adrenal tumours of less than 6.0 cm in size. Surgical decision making based on size should take this limitation into account.

Adrenal Gland Neoplasms↗
PubMed1999

Teratoma in the region of adrenal gland: a unique entity masquerading as lipomatous adrenal tumor.

BACKGROUND: The aim of this study was to establish the clinical and pathologic aspects of 3 atypical lipomatous lesions in the region of the adrenal gland. METHODS: Three young Chinese patients (ages 18, 18, and 37 years) were seen for nonspecific back pain. Radiologic examination revealed a lipomatous lesion in the region of the adrenal gland, and hormonal assessment was normal. Calcification was noted in 2 of the 3 lesions. Adrenalectomy was performed because of the size (diameter 7.5, 10, 11 cm) of the tumors with suspected local symptoms. RESULTS: On gross examination 2 tumors were cystic and 1 was solid. In all 3 patients the diagnosis was mature teratomas. The tumors were composed of mature tissues arising from more than 1 germinal layer. There was no evidence of immature elements or malignancy. Adipose tissue was the predominant component in the tumors. There was no evidence of recurrent diseases in all these patients during follow-up. CONCLUSIONS: To our knowledge, this is the first report of teratomas occurring in the adrenal region. Teratoma should clinically and radiologically be included in the differential diagnoses of lipomatous adrenal lesions. Excision of the teratoma is advocated.

Adolescent↗
PubMed1999

Telomerase activity in thyroid malignancy.

Telomerase activity seems to play a role in the development and pathogenesis of thyroid carcinoma. Its incidence of expression and its application as a tumor marker remain to be elucidated. Thyroid tissues obtained during thyroidectomy from 1996-1998 were rapidly frozen and stored at -80 degrees C until processed. Telomerase activity was determined using telomeric repeat amplification protocol (TRAP). Histology of the tissue examined (67 benign and 59 malignant) was reviewed. Telomerase activity was detected in 15 of 52 papillary carcinomas (29%); 1 of 1 thyroid lymphoma (100%); 1 of 2 anaplastic carcinomas (50%); and 2 of 16 lymphocytic thyroiditis specimens (13%). Telomerase activity was not detectable in 35 normal thyroid, 9 follicular adenoma, 7 nodular hyperplasia, 2 follicular carcinoma, and 2 medullary carcinoma. Lymphocytic thyroiditis was detected in 8 of 37 (22%) apparently normal thyroid tissues adjacent to papillary thyroid carcinoma and telomerase activity was present in 2 of these 8 specimens (25%). In conclusion, telomerase does not appear to be frequently activated in papillary thyroid carcinoma. The association of lymphocytic thyroiditis with papillary thyroid carcinoma may limit its clinical usefulness as a tumor marker.

Adolescent↗
PubMed1999

Malignant lymphoma of the thyroid. A 30-year clinicopathologic experience and an evaluation of the presence of Epstein-Barr virus.

Lymphoma of thyroid is uncommon, and Epstein-Barr virus (EBV) is found in many lymphomas. We studied the clinicopathologic characteristics in Hong Kong Chinese and analyzed the presence of EBV in thyroid lymphomas by reviewing data collected during 3 decades. We studied EBV gene expression by in situ hybridization and immunohistochemistry. Primary thyroid lymphomas were found in 23 patients (diffuse large B-cell lymphoma, 18; marginal zone B-cell lymphoma, 4; plasmacytoma, 1), and secondary lymphomas were found in 9 patients (diffuse large B-cell lymphoma, 3; Burkitt lymphomas, 2; Burkitt-like lymphoma, 1; hairy cell leukemia, 1; nasal T-cell and natural killer cell lymphoma, 1; and intestinal T-cell lymphoma, 1). Primary thyroid lymphomas were large (mean, 7 cm), found commonly in older women, and often misdiagnosed as undifferentiated carcinomas. Fine-needle aspiration was not helpful for diagnosis. Fifteen patients had Hashimoto thyroiditis. A history of thyrotoxicosis was found in 3 patients, and coexistence of 3 diseases (papillary microcarcinomas, primary thyroid lymphoma, and Hashimoto thyroiditis) was found 4 patients. The 5-year survival rate for primary thyroid lymphoma was 53%. Combined surgery and radiotherapy seemed to be the best treatment. Secondary thyroid lymphomas often were asymptomatic. EBV messenger RNAs were detected in 1 primary and 1 secondary thyroid lymphoma. The EBV gene expression in primary thyroid lymphoma showed a type II latency pattern. Thyroid lymphomas in Chinese had important clinicopathologic features. EBV may have a role in a subset of cases.

Aged↗
PubMed1999

From open to laparoscopic adrenalectomy: a review of 16-year experience.

OBJECTIVE: To review the experience with adrenal surgery which was associated with significant morbidity and notable mortality in the past, although laparoscopic approach is beginning to be accepted as the procedure of choice. METHODS: The indications and results of adrenalectomy in 104 patients (36 men, 68 women) over the past 16 years were reviewed. Any potential improvement of surgical results over time was analyzed. RESULTS: Ninety-three patients (89%) had functional problems while malignancy was present in 11 patients (11%). Anterior approach was employed in 27 patients, posterior in 56, lateral in 10, and laparoscopic in 11. One patient required conversion from laparoscopic to anterior approach. No operative mortality was seen, but the morbidity occurred in 16.7%. Complication rate decreased significantly in this study period (1981-1990 versus 1991-1996, 22% versus 5%; P = 0.02). Laparoscopic adrenalectomy was successfully performed for 59% of the patients requiring adrenalectomy recently, compared to 68% of posterior adrenalectomy in the past. CONCLUSIONS: Adrenal surgery is a safe procedure, associated with acceptable morbidity, which has decreased over time. Laparoscopic adrenalectomy is becoming the preferred approach for the majority of patients requiring adrenalectomy.

Adolescent↗
PubMed1998

Mechanism of protective immunity against influenza virus infection in mice without antibodies.

There is considerable interest in developing viral vaccines intended to induce T cell immunity, especially cytotoxic CD8+ T lymphocytes, when Abs are not protective or are too narrow in viral strain specificity. We have studied protective immunity in doubly inactivated (DI) mice devoid of Abs and mature B cells. When infected with influenza B virus, these mice cleared the virus in a process dependent upon CD8+ T lymphocytes. Cytotoxic activity was detected in lung lymphocytes of DI mice after primary or secondary infection, and was abrogated by depletion of CD8+ cells in vivo. Challenge experiments showed that DI mice could be protected by immunization against reinfection 1 mo later, and protection was virus specific. Depletion of CD4+ or CD8+ T cells in vivo during the challenge period partially abrogated, and depletion of both subsets completely abrogated, the protection. This indicates that both CD4+ and CD8+ T cells are required effectors in the optimal control of virus replication. Thus, when Abs fail to protect against varying challenge viruses, as is the case with variant strains of influenza and HIV, there is hope that T cells might be able to act alone.

Animals↗
PubMed1998

Surgical strategy for insulinomas in multiple endocrine neoplasia type I.

BACKGROUND: Hyperinsulinemia in multiple endocrine neoplasia type I (MEN-I) is a rare but potentially curable condition that presents difficulties not encountered in sporadic cases. METHODS: The present report documents our surgical approach to 3 MEN-I patients with hyperinsulinemia. RESULTS: Primary hyperparathyroidism was manifested in all 3 patients at the time of presentation. Distal subtotal pancreatectomy with enucleation of tumor at the head of pancreas detected intraoperatively resulted in immediate cure of 2 patients. Persistent disease occurred in 1 patient after enucleation of tumor at the head of the pancreas guided by preoperative imaging elsewhere. The patient was subsequently cured by distal subtotal pancreatectomy. Pathology revealed multiple tumors (4 to 14) in all patients. CONCLUSIONS: A different surgical strategy with an aim of distal subtotal pancreatectomy and enucleation of any tumor identified in the head of pancreas is the treatment of choice for hyperinsulinemia in MEN-I patients.

Adult↗
PubMed1998

Posterior or laparoscopic approach for adrenalectomy.

BACKGROUND: The pathologies and size of adrenal lesions removed through the open posterior and laparoscopic routes share remarkable similarities. This study aims at comparing the relative merits of these two approaches. METHODS: Patients with adrenal tumors operated on by posterior approach (n = 56) and transabdominal laparoscopic approach (n = 12) between January 1981 and May 1997 were retrospectively reviewed. RESULTS: The two groups were comparable in terms of age, and the position, size, and weight of the tumor. The operative time of posterior adrenalectomy was significantly shorter than that of laparoscopic adrenalectomy (median 120 minutes versus 160 minutes), whereas laparoscopic adrenalectomy was associated with less parenteral analgesic requirement (median 0 mg versus 225 mg), a shorter hospital stay (median 3 days versus 5 days), and a shorter duration off work (median 11 days versus 26 days). The estimated blood loss was also significantly reduced in the laparoscopic group (median 50 mL versus 150 mL). CONCLUSIONS: Laparoscopic adrenalectomy is replacing posterior adrenalectomy to become the procedure of choice for the majority of patients undergoing adrenalectomy.

Adolescent↗
PubMed1998

Benefits of exercise training in patients on continuous ambulatory peritoneal dialysis.

We examined the effects of a 12-week exercise program on the exercise tolerance, blood biochemistry, blood pressure (BP) control, cardiac function, and quality-of-life (QOL) scores in 13 patients undergoing continuous ambulatory peritoneal dialysis (CAPD; six men, seven women; mean age, 46.5+/-12.8 years; mean duration on dialysis, 4.8+/-3.8 years). The patients underwent exercise training on treadmill, bike, and arm ergometers thrice weekly. Seven CAPD patients matched for age, sex, and duration on dialysis served as controls. The mean peak aerobic capacity (VO2peak) of the exercisers increased by 16.2% after training (pre- and postexercise, 17.2+/-5.2 v 20.0+/-6.4 mL/kg/min; P=0.004). Although there were no significant changes in serum urea, creatinine, albumin, and hematocrit levels; left ventricular diastolic/systolic diameters; and ejection fraction, an increasing trend of high-density lipoproteins (HDLs) was observed in the exercisers (baseline v postexercise, 33+/-11 v 40+/-14 mg/dL; P=0.06). Twenty-four-hour ambulatory BP monitoring showed a significant increase in daytime systolic BP in the exercisers (pre- and postexercise, 142+/-26 v 157+/-22 mm Hg; P=0.003), but no significant changes could be found in the ambulatory daytime diastolic BP, nocturnal BP, and resting clinic BP. The patients' QOL improved after training, with better scores in two Kidney Disease Quality of Life scales (KDQOL): burden of kidney disease and physical functioning. Two mild and uncomplicated hypotensive episodes were reported in two patients immediately after training. No changes occurred in exercise capacity, blood biochemistry, BP profile, and QOL scores in the controls. We conclude that structured aerobic exercise is safe and can improve the exercise tolerance and QOL outcomes in CAPD patients.

Adult↗
PubMed1998

Postoperative hypocalcemia in patients who did or did not undergo parathyroid autotransplantation during thyroidectomy: a comparative study.

BACKGROUND: Permanent hypoparathyroidism is a recognized complication of thyroidectomy. Apart from preservation of parathyroid glands in situ by meticulous dissection, parathyroid autotransplantation (PTHAT) has been performed increasingly to avoid permanent hypoparathyroidism. METHODS: From January 1995 to October 1997, PTHAT was performed routinely for devascularized or inadvertently removed glands in 98 (36%) of 271 patients undergoing thyroidectomy. Potential risk factors and the impact of PTHAT on postoperative hypocalcemia were studied. RESULTS: Postoperative hypocalcemia occurred in 40 patients (14.8%), whereas 5 patients (1.8%) had permanent hypocalcemia during a median follow-up of 9 months. The incidence of transient hypocalcemia (n = 35) was higher in patients who underwent PTHAT (21.4%) than in patients who did not undergo PTHAT (8.1%) (P < .01). Permanent hypocalcemia occurred only in patients who did not undergo PTHAT. None of the 21 patients who had postoperative hypocalemia after PTHAT had permanent hypoparathyroidism compared with 26% (5/19) of patients who did not undergo PTHAT (P = .018). When the resected thyroid gland was examined for parathyroid tissue, the incidence of positive identification was higher in patients who did not undergo PTHAT (13%) than in patients who did undergo PTHAT (4%) (P = .015). CONCLUSIONS: Patients with postoperative hypocalcemia after PTHAT have virtually no risk of having permanent hypoparathyroidism. A more careful examination of the resected thyroid tissue can help to identify inadvertently removed parathyroid glands for autotransplantation.

Adolescent↗
PubMed1998

Role of p53 tumor suppressor gene in pancreatic endocrine tumors of Chinese patients.

OBJECTIVE: The molecular genetic of pancreatic endocrine tumor (PET) has rarely been studied in depth because of its rarity. The aim of this study is to determine if there is any implication of p53 overexpression on the pathogenesis and clinicopathological parameters of PET. METHODS: This study examines the immunohistochemical expression of the p53 gene product in 52 PETs (32 insulinomas, three gastrinomas, two glucagonomas, one carcinoid, and 14 nonfunctional tumors) from Chinese patients (27 men, 25 women) collected over a 23-yr period. Of these, 21% were malignant. RESULTS: Irrespective of their demographic data, clinical behavior, hormonal status, or pathological features, none of the 52 PETs showed p53 overexpression. CONCLUSIONS: This observation, together with an analysis of the literature, suggests that p53 gene aberrations may not be important in the pathogenesis of PET.

Adenoma, Islet Cell↗
PubMed1998

Rapid cytomegalovirus pp65 antigenemia assay by direct erythrocyte lysis and immunofluorescence staining.

A rapid cytomegalovirus (CMV) pp65 antigenemia assay with direct erythrocyte lysis (DL) with 0.8% NH4Cl, followed by indirect immunofluorescence staining (IF), was evaluated with 82 blood samples from renal transplant recipients, and the results were compared to those of the conventional antigenemia assay with dextran sedimentation and two-cycle alkaline phosphatase, anti-alkaline phosphatase staining (DS-APAAP). The DL-IF modification gave a higher leukocyte yield compared to DS-APAAP (75.4 versus 54.9%; P < 0.05), with similar leukocyte viability rates of >95%. The DL-IF methodology involved fewer technical steps, and the assay time was shortened from 5 h to less than 3 h. Nineteen of the 82 samples concordantly tested positive for pp65 antigenemia by both assays, and the readings showed a good correlation (r = 0.996; P < 0.01). No discordant results were observed. We conclude that the CMV pp65 antigenemia assay by this novel DL-IF modification is technically simpler, cheaper, and less time-consuming but yields results comparable to those of the conventional DS-APAAP assay. The shortened assay time and increased capacity to handle more samples confer distinct advantages in the rapid diagnosis and prompt treatment of CMV disease in immunosuppressed patients.

Antigens, Viral↗