Biomedical subjects

K Y Lam

Publications and source records attributed to K Y Lam.

At least 91 records · Page 5Linked to original sources

PubMed1999

A randomized controlled trial comparing midwife-managed care and obstetrician-managed care for women assessed to be at low risk in the initial intrapartum period.

OBJECTIVE: To compare the efficacy of midwife-managed care and obstetrician-managed care for women assessed to be at low risk in the initial intrapartum period. METHODS: 1,050 women assessed to be at low risk on admission to labour ward in the Prince of Wales Hospital participated in this study. By computer-generated random allocation, 563 (54%) women were assigned to Group A (experimental) under midwifery care, and 487 (46%) women to Group B (control) under obstetrician care. The outcomes and complications between the 2 groups were compared. Data were analyzed by 2 x 2 contingency tables and Chi-square. RESULTS: 150 (26.6%) women in the experimental group were taken over by the obstetricians. 46 (30.7%) women were transferred to obstetrician-management for the preference of epidural analgesia. The other reasons for taken over the remaining 104 (69.3%) women were fetal distress, poor progress of labour, complications in first or second stage of labour. The experimental group had less oxytocic augmentation (Chi-square = 7.49, p = 0.006) and the insertion of intravenous infusion (Chi-square = 5.34, p = 0.02). Both groups had similar outcomes on normal delivery, operative vaginal delivery, caesarean section and complications. CONCLUSIONS: Midwife-managed care is as safe as obstetrician-managed care for women who were assessed to be at low risk in the intrapartum period. Routine visit by obstetrician is not necessary and the midwives are able to detect complications in the course of labour and alert the obstetrician for taking the necessary action.

Cesarean Section↗

PubMed1999

The clinicopathological significance of p21 and p53 expression in esophageal squamous cell carcinoma: an analysis of 153 patients.

OBJECTIVE: The p21 gene is thought to play a central role in tumor suppression. The aim of this study was to examine the clinicopathological role of p21 and p53 in esophageal squamous cell carcinomas. METHODS: The expression of p21 and p53 proteins in 153 Chinese patients (131 men, 22 women) with resected esophageal squamous cell carcinomas was investigated by the immunohistochemical method. Correlation between p21 and p53 expression and clinicopathological features was examined. RESULTS: The expression of p21 and p53 was detected in 70% and 64% of the tumors, respectively. The staining of p21 and p53 was also found in squamous carcinoma in situ, dysplasia, and nontumor epithelium. p21 expression was often weak in the suprabasal cells and found in better differentiated tumors. There was no significant correlation between the expression of p21 and the abnormal accumulation of p53. The prognosis of the patients depended on the size, stage, and p21 expression of the lesion. In stage III lesions with tumor diameter < or = 7.5 cm (n = 93), patients with loss of p21 expression had better survival. The survival rates of patients were worse if they had expression of both p21 and p53. CONCLUSIONS: Thus, p21 and p53 had prognostic value for esophageal squamous cell carcinomas. Loss of p21 expression was shown without p53 alternations, indicating that other mechanisms are also involved in turning off the gene. The pattern of p21 and p53 expression predicts an aggressive clinical course of esophageal squamous cell carcinomas.

Actuarial Analysis↗

PubMed1999

Oesophageal mesenchymal tumours: clinicopathological features and absence of Epstein-Barr virus.

BACKGROUND: Recent studies have suggested that the Epstein-Barr virus (EBV) is associated with smooth muscle tumours (leiomyoma and leiomyosarcoma) in patients with human immunodeficiency virus and in organ transplant recipients. Leiomyoma is the most common mensenchymal tumour found in the oesophagus. AIM: To report a single institution experience on oesophageal mesenchymal tumours and to determine whether EBV is associated with these tumours. METHODS: 40 sporadic oesophageal mesenchymal tumours were studied and their diagnosis confirmed on pathological review and immunohistochemical studies. Formalin fixed, paraffin was embedded tissues from these tumours were analysed for EBV using in situ hybridisation for two messenger RNA (mRNA) probes, EBER and BamH1 W. RESULTS: The oesophageal mesenchymal tumours comprised 36 leiomyomas, two undifferentiated stromal tumours, and two gastrointestinal autonomic nerve tumours (GANTs). Median age of the patients with leiomyoma (26 men, 10 women) was 62 years (range 30 to 85) and 81% of them had an asymptomatic lesion. The median longitudinal size was 1.2 cm. Multiple leiomyomas were seen in 11% of the patients and calcification was noted in one tumour. Coexisting squamous cell carcinoma was found in one third of cases. The stromal tumours were small, asymptomatic, and located in the lower third of the oesophagus, while the GANTs were large, symptomatic, and found in the upper third of the oesophagus. EBV mRNAs were not detected in all these tumours. CONCLUSIONS: The clinicopathological features of oesophageal leiomyoma, undifferentiated stromal tumour, and GANT were different. Some oesophageal leiomyomas were associated with oesophageal squamous cell carcinomas. EBV is not associated with sporadic oesophageal mesenchymal tumours.

Autonomic Nervous System Diseases↗

PubMed1999

Mutational analysis of the PTEN/MMAC1 gene in primary oesophageal squamous cell carcinomas.

AIM: To investigate whether PTEN/MMAC1 mutations play a role in the carcinogenesis of oesophageal squamous cell carcinoma. METHODS: A panel of 33 primary oesophageal squamous cell carcinoma tumour samples and 20 corresponding morphologically normal tissues was examined for mutations in all nine exons of the PTEN/MMAC1 gene by means of polymerase chain reaction single strand conformational polymorphism analysis (PCR-SSCP) and direct DNA sequencing methods. RESULTS: Only one of 33 oesophageal squamous cell carcinomas showed an aberrant SSCP band. Further sequencing analysis of this sample revealed an 802 -29 T-->C substitution in intron 7. PTEN/MMAC1 mutations were not found in the mutational "hot spot" in exon 5, even after direct sequencing of six oesophageal squamous cell carcinoma samples and three normal tissues. However, a deletion of one nucleotide T at position 492 +8 in intron 5 was seen in all samples. CONCLUSION: These results suggest that PTEN/MMAC1 mutations do not play a major role in the carcinogenesis of oesophageal squamous cell carcinoma.

Aged↗

PubMed1999

Molecular pathology and clinicopathologic features of penile tumors: with special reference to analyses of p21 and p53 expression and unusual histologic features.

OBJECTIVES: To examine the histologic features of p21 in penile tumors and to determine the role of p21 and p53 in the pathogenesis of this group of tumors. METHODS: The clinicopathologic features of 87 patients with penile tumors were studied. The expression of p53 and p21 proteins in 49 cases was investigated by immunohistochemistry. RESULTS: Of the 87 tumors studied, 84 represented primary penile tumors (72 malignant and 12 benign) and 3 represented secondary tumors (2 from bladder, 1 from nasopharynx). The primary malignant penile tumors included 66 surface carcinomas with squamous differentiation (92%), 3 cases of Paget disease (4%), 1 case of Bowen disease (1%), and 2 penile urethral squamous cell carcinomas (3%). The former group was subdivided into squamous cell carcinoma (n = 50), verrucous carcinoma (n = 8), basaloid squamous cell carcinoma (n = 3), adenoid squamous cell carcinoma (n = 3), spindle cell carcinoma (n = 1), and adenosquamous carcinoma (n = 1). The benign tumors were squamous cell papillomas (n = 10) and fibromatoses (n = 2). Expression of p21 and p53 was noted in 40% and 89%, respectively, of the 47 patients with primary surface penile carcinoma with squamous differentiation. Positive p21 and p53 expression was also seen in 2 cases of Paget disease. Staining for p21 was often weak and was found in the suprabasal region of carcinomas with squamous differentiation, while p53 expression was seen in the basal region of squamous cell carcinomas. Preinvasive lesions also showed p21 and p53 expression. An inverse correlation between p53 and p21 expression (p53(+)/p21(-) or p53(-)/p21(+)) was noted in half of the squamous cell carcinomas, 4 of 5 verrucous carcinomas, 2 of 3 basaloid squamous cell carcinomas, and in 1 spindle cell carcinoma. The other cases did not show this correlation. CONCLUSIONS: Penile tumors had different histologic variants and p21/p53 expression patterns. Expression of p21 did play a role in some tumors and could be dependent or independent of p53 expression.

Adult↗

PubMed1998

Expression of P-glycoprotein, a multidrug-resistance gene product, is induced by radiotherapy in patients with oral squamous cell carcinoma.

BACKGROUND: It has been observed that patients who have previously undergone radiotherapy have a lower rate of response to chemotherapy. METHODS: The authors investigated the effects of radiation on the expression of P-glycoprotein (Pgp), a multidrug-resistance gene product, in 56 patients with primary oral cancer. No patients received prior or concurrent chemotherapy. The 56 patients consisted of 3 groups: 1) 20 patients with preradiation or pretreatment specimens only, 2) 18 patients with both pre- and postradiation specimens, and 3) 18 patients with postradiation specimens only. Pgp expression was determined by immunohistochemistry with two monoclonal antibodies, C219 and C494. RESULTS: Among patients in Groups 1 and 2, only 1 (2.6%) and 2 (5.3%) patients had Pgp expression in their tumors before treatment with C219 and C494, respectively. For Group 2 patients, 66.7% and 72.2% had tumors that expressed Pgp with the two antibodies, respectively, only after and not prior to radiation. When patients in Groups 2 and 3 were combined, 63.9% and 72.2% had Pgp expression with the two antibodies, respectively, after radiation. Pgp expression was significantly induced after radiation compared with expression before treatment (P < 0.001). Overexpression of p53 protein, detected by immunohistochemistry with DO-7 antibody, was seen in the tumors of 40 patients (71.4%), and the status was quite consistent throughout radiotherapy. Pgp expression had no significant association with p53 protein expression. CONCLUSIONS: Pgp expression was significantly induced by radiation in human oral cancers. This induction of Pgp expression likely confers multidrug resistance to the cancer cells and may affect the efficacy of subsequent or concurrent chemotherapy. It may explain the lower rate of response to chemotherapy among patients who have previously had radiotherapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

Clinicopathological analysis of local spread of carcinoma of the tongue.

BACKGROUND: The aims of the study are three-dimensional analysis of mode and distance of local spread of oral tongue carcinoma. METHODS: The glossectomy specimens were examined in the coronal plane in 3 mm thickness section. RESULTS: There were 50 glossectomy specimens. The maximum spread was 1.8 cm. Ninety-six percent of specimens had local spread within 1.2 cm. The distance of spread was not correlated with tumor size, including the diameter, depth, and volume. The incidence of local recurrence was 27% with positive histological margin. Perineural infiltration was the most important prognostic factor for local recurrence and survival. CONCLUSIONS: A minimum of 1.5-cm surgical resection margin is recommended. A smaller margin is not recommended as it has significant risk of local recurrence. A maximum of 2-cm surgical resection margin is recommended; larger margins will increase the surgical morbidity without a significant advantage of local control.

Adolescent↗

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

Desmoplastic variant of ameloblastoma in Chinese patients.

Desmoplastic ameloblastoma is a rare tumour, and we know of only 43 previously reported cases. We report seven Chinese patients (five men and two women) with the desmoplastic variant of ameloblastoma, which makes up 9% of all ameloblastomas diagnosed during the years 1981-1995. The age ranged from 18 to 68 years (mean 43). Five of the tumours were in the maxilla and two were in the mandible. Five of them were situated anteriorly, the remaining two cases involving both anterior and posterior maxilla. The features of the 42 cases previously reported were reviewed and were compared with those in the present study. Our results differ in that we found a male predominance, wider age range and more tumours in the maxilla. Histologically, this variant of ameloblastoma is characterized by abundant collagenous stroma. Because the epithelial clusters may show prominent squamous metaplasia or may be compressed into thin strands in most areas, the appearance may mimic a squamous odontogenic tumour or odontogenic fibroma. The behaviour of this variant of ameloblastoma is likely to be the same as that of the classic ameloblastoma.

Adolescent↗

PubMed1998

C-erbB-2 protein expression in oesophageal squamous epithelium from oesophageal squamous cell carcinomas, with special reference to histological grade of carcinoma and pre-invasive lesions.

AIMS: C-erbB-2, an oncogene, is member of the growth factor receptor family. Its role in activation of oesophageal squamous cell carcinoma is poorly understood. The aim of this study was to evaluate the part played by c-erbB-2 in oesophageal squamous cell carcinoma in Hong Kong Chinese patients. METHODS: We examined the expression of the c-erbB-2 oncoprotein in 104 oesophageal squamous cell carcinomas from 89 men and 15 women, ranging in age from 41 to 89 years (mean 63). C-ercB-2 expression was studied with monoclonal antibody, using an antigen retrieval method. RESULTS: Focal c-erbB-2 membrane staining was present in 10 (10%) of 104 squamous cell carcinomas. Staining was also noted in the adjacent dysplastic epithelium (n=2) and non-tumour inflamed epithelium (n=2). In carcinomas, the c-erbB-2 membrane staining was identified only in superficial well-differentiated tumour cells and the expression did not predict biological behaviour. CONCLUSIONS: We conclude that the c-erbB-2 oncoprotein is expressed in a portion of oesophageal squamous cell carcinomas and precursor lesions. This suggests that c-erbB-2 activation plays a certain role, mostly probably during the early stages, in carcinogenesis in oesophageal squamous cell carcinomas from Hong Kong Chinese 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

Glomerulonephritis associated with basaloid squamous cell carcinoma of the oesophagus. A possible unusual paraneoplastic syndrome.

A 70-year-old man presented with rash, microscopic haematuria and proteinuria. The renal biopsy showed mesangial proliferative glomerulonephritis with mesangial IgA deposition. He was subsequently found to have basaloid squamous carcinoma of the oesophagus. This possible association between IgA nephropathy and oesophageal basaloid squamous carcinoma has never been reported.

Aged↗

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

Palatal pleomorphic adenoma with florid squamous metaplasia: a potential diagnostic pitfall.

We report a case of pleomorphic adenoma with extensive squamous metaplasia in the palate of a 52-year-old Chinese man. The dimensions of the tumor were 15 x 13 x 13 mm. More than 95% of the epithelial element in the tumor was composed of sheets of squamous cells with cyst formation. The pathogenesis, potential diagnostic pitfalls, proliferative activity and cytokeratin expression of this tumor are discussed.

Adenoma, Pleomorphic↗

PubMed1998

Metastatic tumors of the thyroid gland: a study of 79 cases in Chinese patients.

OBJECTIVE: To evaluate the clinical and pathologic impact of metastases to the thyroid gland. CASE MATERIAL: We studied the clinical/autopsy records and pathologic features of 79 Chinese patients (38 men, 41 women) with secondary tumors of the thyroid over a 26-year period. RESULTS: The incidence of thyroid secondaries at autopsy was 0.5% and at thyroidectomies for malignancy was 1.2%. Eighteen (23%) of the 79 patients presented with an enlarged mass in the thyroid. The diagnosis of metastasis in the thyroid gland was suspected clinically in six cases. Fine-needle aspiration cytology detected an 80% malignancy rate, but in only half of such cases was the diagnosis specific for secondary malignancy. Many of the metastatic lesions in the thyroid gland occurred shortly after the detection of primaries (mean latency period, 9 months). The time from diagnosis of the primary tumor to metastasis to the thyroid gland was greater than or equal to 3 years in only eight patients. The majority (81%) of the secondary tumors were carcinomas. Of these, the lung was the most common primary tumor site (43%), followed by the breast (9%) and stomach (8%). Rare sources of primary tumors, such as nasopharyngeal carcinoma, choriocarcinoma, malignant phylloides, and osteosarcoma, were also found. The metastatic lesions in the thyroid gland could be identified macroscopically in 43 patients (54%). Lesions were often solitary (n = 24) rather than diffuse (n = 8) or multiple (n = 11). Microscopic examination revealed that secondary thyroid tumors were often moderate or poorly differentiated adenocarcinomas (n = 42). All the patients died shortly after the appearance of metastatic lesions in the thyroid gland. CONCLUSIONS: Metastasis in the thyroid gland is uncommon and may be a diagnostic problem. Its presence often indicates a poor prognosis.

Adenocarcinoma↗

PubMed1997

Prevalence of HPV infection in esophageal squamous cell carcinoma in Chinese patients and its relationship to the p53 gene mutation.

Human papillomavirus (HPV), in particular types 16 and 18, is positively associated with anogenital cancers and may be an important etiologic factor in their pathogenesis. The goal of our study was to investigate the role of HPV infection in the pathogenesis of esophageal squamous cell carcinoma (ESCC) and its relationship with the p53 mutation. We have examined ESCC collected from Sichuan, China, for the presence of HPV infection and p53 mutation. The presence of HPV DNA was detected by PCR-Southern analysis while the p53 mutation was analyzed by PCR-SSCP. High-risk HPV (types 16 and 18) DNA was detected in 32 out of 152 cases of ESCC examined. In contrast, HPV DNA was not detected in normal esophageal tissues excised from the distant end (tumor free) of resected ESCC. Mutation of the p53 gene was detected in 22 out of 55 cases of ESCC. The distribution of the 22 p53 mutation was: 5 in exon 5, 1 in exon 6, 5 in exon 7, 10 in exon 8 and 1 in exon 10. The p53 mutation was detected at a significantly lower rate in ESCC with HPV infection. Our results support a role of HPV infection in the pathogenesis of ESCC from a high-incidence area.

Adult↗

PubMed1997

Prevalence and predictive value of p53 mutation in patients with oesophageal squamous cell carcinomas: a prospective clinico-pathological study and survival analysis of 70 patients.

The tissues from 70 Chinese patients with oesophageal squamous cell carcinoma were prospectively collected to study for the pattern of p53 mutations and its relationship with clinico-pathological features and prognosis using immunohistochemistry, polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis and DNA sequencing. p53 over-expression and p53 mutations were detected in 73% and 44% of the patients. These p53 aberrations had no relationship with the patient age, sex, smoking/drinking habits and tumor site, size or stage. The p53 over-expression was more intense in moderately/poorly-differentiated squamous cell carcinomas. Thirty-three p53 mutations were noted in 31 patients; 18.2% in exon 5, 15.2% in exon 6, 33.3% in exon 7 and 33.3% in exon 8. Mutations were primarily point mutations and common in codons 248, 273 and 285. There were 46% transversions, 36% transitions and 18% frameshift. The survival of the patients depended mainly on the extent of resection. In patients with stage III oesophageal cancer, the median survival of those with p53 mutations was 6.8 months whereas those without was 12.5 months. The results were of clinical importance although the value did not reach statistical significance. Thus, there was a definite role of p53 mutations in the pathogenesis of oesophageal squamous cell carcinomas. p53 mutations were not synonymous with p53 over-expression. The distribution of p53 mutations in oesophageal cancers suggested that the etiologic contribution might be complex and probably involve different exogenous and endogenous exposures. p53 mutations also appear to play a role in predicting the survival of patients with stage III oesophageal squamous cell carcinomas.

Adult↗

PubMed1997

Pancreatic insulinomas. A 15-year experience.

OBJECTIVE: To describe our experience in the management of patients with pancreatic insulinomas, emphasizing the need for preoperative localization and the outcome of surgical treatment. DESIGN: A case series. SETTING: A university hospital in Hong Kong. PATIENTS: From 1981 to 1995, 27 patients with pancreatic insulinomas were surgically treated; the mean follow-up was 25.4 months. MAIN OUTCOME MEASURES: Postoperative morbidity and euglycemia during the follow-up period. RESULTS: The accuracy of tumor localization by ultrasonography, computed tomography, and angiography was 33%, 44%, and 52%, respectively. Venous sampling for an insulin assay regionalized 90% of the tumors. In 24 patients with solitary tumors, most lesions detected or missed by preoperative localization could be either seen (n = 14) or palpated (n = 22). Intraoperative ultrasonography (n = 17) has been routinely performed since 1987; nonpalpable tumors were imaged in 2 of 15 patients with solitary tumors. Eight solitary occult tumors were detected by palpation alone or a combination of palpation and intraoperative ultrasonography. Operative mortality occurred in 1 (3.7%) of the 27 patients, while major morbidity developed in 9 (33%) of the patients. Euglycemia was achieved in 25 patients. Surgery cured all patients with benign insulinomas, whereas the cure rate for patients with malignant neoplasms was only 33%. The type of surgical treatment or correct preoperative localization did not affect the outcome of surgery. CONCLUSIONS: Pancreatic insulinomas can be readily localized intraoperatively despite failed preoperative localization studies. Surgical treatment cured benign adenomas but was associated with notable morbidity.

Adolescent↗