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Biomedical subjects

S L Loke

Publications and source records attributed to S L Loke.

At least 37 records · Page 2Linked to original sources
PubMed1993

Histochemistry of mucin secreting components in mucoepidermoid and adenosquamous carcinoma of the oesophagus.

AIMS: To determine the direction of differentiation of the mucin secreting components in a rare group of oesophageal tumours--oesophageal squamous cell carcinomas with prominent mucin secreting components (mucoepidermoid carcinomas and adenosquamous carcinomas). METHODS: In a review of 617 cases of primary carcinoma of the oesophagus, 16 cases of squamous cell carcinoma with prominent mucin secreting components were studied using a battery of histochemical techniques. RESULTS: The mucin produced by these tumours was mixed and included a variable content of enzyme labile sialomucin (positive for mucicarmine, periodic acid Schiff, and alcian blue, and sensitive to sialidase digestion and negative for high iron diamine-alcian blue). Retrospective analysis of endoscopic biopsy specimens taken from these tumours showed that mucin was present in five (42%) cases. CONCLUSIONS: The glandular component of this group of tumours histochemically differentiated in the direction of oesophageal glands: examination of the mucin secreting component in squamous cell carcinoma in resected specimens is therefore required for recording the true incidence of this type of tumour.

Aged↗
PubMed1992

Epstein-Barr virus DNA in nasopharyngeal carcinomas from Chinese patients in Hong Kong.

AIMS: To investigate the presence of Epstein-Barr virus (EBV) in cases of nasopharyngeal carcinoma (NPC) in Chinese patients living in Hong Kong. METHODS: Nasopharyngeal biopsy specimens, formalin fixed and paraffin wax embedded, from 24 patients, eight with undifferentiated nasopharyngeal carcinoma, eight with well differentiated squamous carcinoma, and eight showing normal tissue histology, were analysed for the presence of Epstein-Barr virus (EBV) DNA by slot-blot hybridisation on extracted unamplified DNA, and also after amplification of EBV specific sequences by the polymerase chain reaction (PCR). RESULTS: DNA slot-blot analysis showed viral DNA in all the undifferentiated, five of the well differentiated tumours, and none of the normal biopsy specimens. PCR studies confirmed positivity in the eight undifferentiated tumours, but six of the well differentiated tumours and three of the normal biopsy specimens showed viral DNA by this method, illustrating its greater sensitivity. CONCLUSIONS: EBV genome is present in appreciable copy number in most cases of well differentiated NPC in Chinese patients in Hong Kong.

Base Sequence↗
PubMed1992

Clonal Epstein-Barr virus genome in T-cell-rich lymphomas of B or probable B lineage.

Seventeen nodal lymphomas (originally diagnosed as T-cell lymphomas based on histological features and immunohistochemical staining results) were studied for the presence of Epstein-Barr virus (EBV) genome, and the results correlated with immunoglobulin and T-cell receptor gene rearrangement analyses performed on the same tissue samples. All four EBV positive cases had clonal rearrangement of the joining region of the immunoglobulin heavy chain (IgJH) gene without clonal T-cell receptor beta-chain (TCR beta) gene rearrangement. Of these, two cases also showed clonally rearranged light chain gene, and they were reclassified as T-cell rich B-cell lymphomas (TRBL). The other two cases lacked clonal kappa or lambda light chain rearrangement and they were reclassified as T-cell rich lymphomas of probable B lineage, based on their isolated IgJH clonal rearrangement. These B-cell lymphomas may be easily misdiagnosed as T-cell lymphomas owing to the presence of an abundant reactive T-cell infiltrate masking the tumor population. The florid T-cell reaction may represent an unusual host response towards a clonal proliferation of EBV bearing B cells.

Blotting, Southern↗
PubMed1992

Clonal Epstein-Barr virus in lymphoepithelioma-like carcinoma of the stomach: demonstration of viral genome by in situ hybridization and Southern blot analysis.

Lymphoepithelioma (LE), originally described in the nasopharynx, is an undifferentiated carcinoma with heavy lymphocytic infiltrate. The tumor is common in Southeast Asia, particularly in southern China, where the Epstein-Barr virus (EBV) association has been documented more consistently than in Western countries. Tumors histologically similar to LE have been described also in other anatomical sites, mostly of fore-gut origin, such as salivary gland, tonsil, lung, thymus, and more recently stomach. We are reporting a case of poorly differentiated gastric adenocarcinoma with marked lymphocytic infiltrate resembling LE (LE-like carcinoma) in a Chinese without evidence of nasopharyngeal carcinoma. In situ hybridization for EBV revealed that the tumor cells but not the lymphoid cells harbored the virus. Tumor cells both in syncytial and glandular areas were positive for EBV. By Southern blot analysis EBV was demonstrated in the DNA extracted from the tumor, while the adjacent normal gastric tissue was negative. Moreover, analysis of the EBV termini revealed a clonal episomal form of the virus. Our case further supports the hypothesis that EBV is associated with LE-like gastric carcinoma. It also strongly suggests that EBV infection has preceded, and thus most likely contributed to, the clonal expansion in this tumor.

Aged↗
PubMed1991

Human papillomavirus 6, 11, and 16 in laryngeal papillomas.

Twenty-seven cases of benign laryngeal papillomas, both single and multiple variants, were analysed for human papillomavirus (HPV) by DNA slot-blot hybridization chiefly to determine the pattern of infection in Hong Kong Chinese. DNA was extracted from paraffin blocks of formalin-fixed tissue and probed separately for HPV 6, 11, 16, and 18. Sixteen cases (59 per cent) showed the presence of at least one of these four HPV genomes. Thirteen cases (48 per cent) were positive for HPV 11 only. Three other cases (11 per cent) showed triple positivity for HPV 6, 11, and 16. None were positive for HPV 18. The predominance of HPV 11 infection contrasts with other series which have shown either an almost equal distribution of HPV 6 and 11 or a predominance of HPV 6. The finding of HPV 16 in three cases was unexpected. Using the polymerase chain reaction (PCR) with primers complementary to the upstream regulatory region of the HPV 16 viral DNA, the presence of HPV 16 genome was confirmed in all three cases. As the number of HPV 16-positive cases in this study is small, analysis of more cases using fresh biopsy material and a wider range of HPV type-specific PCR primers is warranted to determine the relative incidence of HPV subtypes in these benign laryngeal papillomas.

Adolescent↗
PubMed1991

Intensive chemotherapy for adult lymphoblastic lymphomas.

A total of 20 adults patients presenting with previously untreated lymphoblastic lymphoma underwent an intensive chemotherapy protocol. Either the BACOP or the m-BACOD regimen was used for induction. If the patients achieved a complete clinical remission (CR) after three courses, they were given intensive consolidation and maintenance chemotherapy based on a protocol that was modified from the L10/L17M regimen of the Memorial Sloan-Kettering group for acute lymphoblastic leukaemia and lymphoblastic lymphoma. Patients exhibiting localised areas of bulky disease were given additional involved-field radiotherapy. In all, 15 (75%) men and 5 (25%) women were entered in this study. Their median age was 28 years (mean, 30 years; range, 12-64 years). Overall, 3 (15%) had stage II disease, 3 (15%) had stage III disease and 14 (70%) had stage IV disease; 7 (35%) patients exhibited B symptoms and 4 (20%) had bulky disease. The overall (CR) rate was 10/20 (20%), and that following BACOP and m-BACOD therapy was 4/8 (50%) and 6/12 (50%), respectively. In all, 7 of the 10 complete responders (70%) relapsed. The disease-free survival of the ten who achieved a CR was 23% at 3 years. The overall survival of all 20 patients at 3 years was only 37%, and there were very few long-term survivors. More effective treatment for adult lymphoblastic lymphoma is required.

Adult↗
PubMed1991

Chemotherapy for early-stage gastrointestinal lymphoma.

A total of 176 patients with gastrointestinal lymphomas were reviewed. According to a modified staging classification, 51 of them had stage I/II disease and the remaining 125 had stage III/IV disease. In most cases (68%), the histology was intermediate-grade according to the NIH working formulation, and the B-cell immunophenotype was involved in 89% of the 45 cases with a known immunophenotype. The primary site was the stomach in 56% of cases and the bowel in 44%. A significantly higher proportion (P = 0.001) of those with bowel lymphomas had stage III/IV disease (88% vs 57%). The primary gastrointestinal lesion was resected in 122 patients, including all 51 cases of stage I/II disease. In all, 8 stage I/II patients were given radiotherapy alone following surgery and the other 43 underwent chemotherapy; of the latter, 19 received additional radiotherapy following chemotherapy. Chemotherapy was also given to 112 stage III/IV patients, 42 of whom underwent additional radiotherapy. Factors associated with a poorer prognosis included advanced disease, bowel lymphoma and advanced age. Although the complete response (CR) rate according to disease stage was similar, stage I/II patients receiving chemotherapy showed a significantly lower relapse rate, better disease-free survival following CR and improved survival as compared with those receiving radiotherapy alone. However, additional radiotherapy following chemotherapy did not further improve the clinical outcome.

Adolescent↗
PubMed1991

Chemotherapy versus radiotherapy for stage I-II intermediate grade non-Hodgkin's lymphomas.

The clinical outcome of 149 patients with Stage I-II intermediate grade non-Hodgkin's lymphomas was analysed. There were 77 (52%) males and 72 (48%) females. Their median age was 58 years. Eighty patients (54%) had Stage I disease and 69 (46%) Stage II. Twenty-nine (20%) of them received radiotherapy only, 75 (50%) doxorubicin-containing chemotherapeutic regimens and 45 (30%) other less intensive chemotherapy. Sixty-two patients had additional radiotherapy following chemotherapy. Patients receiving other less intensive chemotherapy were significantly older (P = 0.0001) and those receiving radiotherapy alone had a significantly higher proportion of Stage I disease (P = 0.007). Patients receiving less intensive chemotherapy had a significantly low complete response (CR) rate. Patients receiving radiotherapy alone had a significantly high relapse rate and low disease-free survival following CR. However, there was no significant difference in overall survival regardless of the mode of therapy. This lack of survival advantage might be related to the effective salvage chemotherapy in some of the radiotherapy failures and the occasional chemotherapy-related mortality. Additional radiotherapy following chemotherapy did not appear to give further benefit.

Adolescent↗
PubMed1991

Non-Hodgkin's lymphomas involving the parotid gland.

Ten patients with lymphomas involving the parotid gland were studied. There were five males and five females. Their median age was 64 years. There were three cases of stage I disease, two stage II and five stage IV. The histology was small lymphocytic type in four of the five stage IV patients and two of them were associated with Sjögren's syndrome. The other stage IV patient had a diffuse small non-cleaved cell lymphoma. A different pattern of the histology was observed in the five stage I/II patients. They all had an intermediate grade histology and were not associated with Sjögren's syndrome. It was possible that at least some of the patients in the latter group might have their lymphomas arising from the lymph nodes within the gland rather than in the salivary gland parenchyma.

Aged↗
PubMed1991

Direct comparison of peripheral T-cell lymphomas with their B-cell counterpart.

The aim of this study was to determine the effect of immunophenotype on the clinical characteristics and prognosis of 144 adult Chinese patients with non-Hodgkin's lymphomas. Those entities with well-recognised immunophenotype and clinical characteristics were excluded. Significantly more patients with T-cell lymphomas had B symptoms (52 vs. 30%, p = 0.05) and fewer had bulky disease (7 vs. 25%, p = 0.04). Extranodal involvements of liver, spleen, marrow, nasal region and skin were significantly more common in T-cell lymphomas. On the other hand, gastro-intestinal involvement was more commonly seen in B-cell tumours. Induction chemotherapy of comparable intensity was used in treating these patients. The immunophenotype did not appear to affect significantly their prognosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Management of low-grade lymphomas in Hong Kong Chinese.

During a 14-year period, 122 of 840 (14.5) Hong Kong patients with non-Hodgkin's lymphomas were diagnosed to have low-grade lymphomas according to the Working Formulation. Only 28 (23%) of them had stage I and II disease and local radiotherapy appeared to be curative in some of them. Although remissions were achieved with chemotherapy in a majority of the stage III and IV patients, a pattern of continuous relapses was noted in their disease-free survival curve. Multivariate analysis revealed that clinical stage and presence of B symptoms were significant independent prognostic factors.

Adolescent↗
PubMed1991

Combined chemotherapy and radiotherapy for lymphomas of Waldeyer's ring.

The management of 47 patients with stage I and II Waldeyer's ring lymphomas was reviewed. Twenty-one of them received radiotherapy only, and the other 26 received combined chemotherapy and radiotherapy. Patients with primary disease in the nasopharynx, high-grade histology or advanced age were associated with poorer survival. Although the complete response rates were similar, the patients receiving combined chemotherapy and radiotherapy had significantly fewer relapses and a better disease-free survival. However, their survivals were similar. The lack of improvement in the overall survival might be due to the effectiveness of salvage chemotherapy in treating some of the radiotherapy failures and the occasional chemotherapy-related mortality.

Adult↗
PubMed1991

Nasopharyngeal carcinoma: role of marrow biopsy at diagnosis.

Twenty-seven new patients with advanced nasopharyngeal carcinoma were evaluated by marrow biopsy at diagnosis. The marrow trephines and blood clots were evaluated by morphology and immunohistochemical studies for cytokeratin and found negative in all cases. The median follow-up of this group of 27 patients was 22 months, and 7 of them had relapsed in the skeletal system. We conclude, in view of its poor sensitivity, that routine use of marrow biopsy for the staging of nasopharyngeal carcinoma is not recommended.

Biopsy↗
PubMed1991

T-lymphoblastic lymphoma arising in the small intestine.

The authors report the clinical, pathological and immunological features of a case of T-lymphoblastic lymphoma presenting with protein-losing enteropathy. There was extensive multifocal involvement of the duodenum, jejunum and ileum. The mediastinum was not enlarged; the peripheral blood picture and bilateral bone marrow trephine biopsies were unremarkable. The tumor cells were positive for terminal deoxynucleotide transferase, CD3, CD2, CD7 and CD10; they were negative for CD1, CD5, CD4, CD8 and HLA-DR. The immunophenotype was that of an immature thymic T-cell. Monocytic and B-cell markers were negative. Despite initial dose reduction in chemotherapy, the patient still developed massive intestinal hemorrhage and succumbed 2 wks after treatment. Postmortem examination confirmed absence of thymic involvement. The overall picture strongly suggests a primary intestinal origin of this T-lymphoblastic lymphoma which contradicts the conventional wisdom that T-lymphoblastic lymphoma arises in the thymus from primitive cortical lymphocytes before rapidly disseminating.

Adult↗
PubMed1991

A clinico-pathological analysis of seventeen cases of non-Hodgkin's lymphoma involving the orbit.

Seventeen patients with non-Hodgkin's lymphoma involving the orbit were studied. There were 12 males and 5 females and their median age was 53 years. Three cases were classified as stage I, two as stage II and 12 as stage IV. The histology was small lymphocytic type in 4 of the 5 stage I and II cases, and immunophenotyping, confirming their B-cell origin, was performed in two of these cases. All stage I and II patients responded favourably to local radiotherapy alone. The 12 stage IV patients had a marked male predominance and more commonly an intermediate grade histology and T-immunophenotype. Several of the orbital lesions seemed to represent extension of nasal lymphomas. The stage IV patients had a poorer survival than the stage I and II patients but the difference was not statistically significant, probably due to the small number of patients.

Adolescent↗