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F C Ho

Publications and source records attributed to F C Ho.

At least 37 records · Page 2Linked to original sources
PubMed1996

Primary B cell lymphoma of the mediastinum.

Primary B cell mediastinal lymphoma has been recognized as a distinct entity recently. This is a retrospective study to define the clinical features and treatment outcome over a 10-year period. Twenty-four consecutive patients (male/female: 11/13) with B cell lymphoma primarily involving the mediastinum were studied. The median age was 34 years. Symptoms were mainly referrable to the chest, with superior vena cava syndrome (SVCO) present in one-third of the patients. Bulky disease was present in over half (58 per cent) and B symptoms were present in 38 per cent of patients. The overall CR rate was 70 per cent and the 5-year OS rates were 56 per cent and 72 per cent for all and CR patients respectively. Five (71 per cent) primary refractory patients and four (66 per cent) relapsed patients died despite salvage therapy. Six relapses occurred at a median of 6 months from treatment. This study showed that primary large B cell lymphoma of the mediastinum is a clinically distinct entity affecting young patients. A significant proportion attained CR and overall, more than half achieved prolonged remission, and most of the relapses occurred early. However, those who failed to attain CR or relapsed still had a poor outcome. An intensive therapy such as autologous bone marrow transplant has to be considered in this subgroup of patients.

Adolescent↗
PubMed1996

Differences in T-cell-receptor gene rearrangement and transcription in nasal lymphomas of natural killer and T-cell types: implications on cellular origin.

Although nasal lymphomas showing midfacial destructive lesions had been classified as T-cell lymphomas, their exact cellular origin is still unclear. Although they usually express a restricted number of T-cell-related antigens, namely, CD2, CD43, and CD45RO, other pan-T or subset-T-lineage antigens, such as CD3 (membrane), CD5, CD4, CD8, and CD7, are frequently absent. Conversely, they often express a natural killer (NK) cell-associated antigen, CD56, but lack other mature NK markets. To study their cellular origin further, the authors analyzed T-cell receptor (TCR) gene transcription in three cases of nasal lymphomas and correlated the findings with the phenotype and gene rearrangement data. Two cases of nasal lymphomas with CD2+CD3(Leu4)-CD19-CD56+ phenotype were shown to express truncated 1.0-kb Tbeta and multiple unrearranged Tdelta transcripts with germline TCR beta, gamma, delta, and immunoglobulin heavy-chain joining region (JH) genes, consistent with NK cell lineage. In contrast, one case of nasal lymphoma with CD2+CD3(Leu4)+CD8+CD19-CD56+ phenotype expressed full-length Talpha, Tbeta, and Tgamma transcripts rearranged TCR beta, gamma, and deleted TCR delta genes, indicating T-lineage, These results support the view that nasal lymphomas can separated into NK-cell and T-cell neoplasms, based on differences genotypic characteristics. The possibility of these tumors being derived from a putative common precursor cell merits further investigation.

Gene Rearrangement, T-Lymphocyte↗
PubMed1996

Report of the Workshop on Nasal and Related Extranodal Angiocentric T/Natural Killer Cell Lymphomas. Definitions, differential diagnosis, and epidemiology.

A workshop jointly sponsored by the University of Hong Kong and the Society for Hematopathology explored the definition, differential diagnosis, and epidemiology of angiocentric lymphomas presenting in the nose and other extranodal sites. The participants concluded that nasal T/natural killer (NK) cell lymphoma is a distinct clinicopathologic entity highly associated with Epstein-Barr virus (EBV). In situ hybridization for EBV an be very valuable in early diagnosis, especially if tissue is sparse. The cytologic spectrum is broad, ranging from small or medium-sized cells to large transformed cells. Histologic progression often occurs with time. Necrosis is nearly always present, and angioinvasion by tumor cells is seen in most cases. Nasal T/NK cell lymphoma has a characteristic immunophenotype: CD2-positive, CD56-positive, but usually negative for surface CD3. Cytoplasmic CD3 can be detected in paraffin sections. Clonal T-cell receptor gene rearrangement is not found. Tumors with an identical phenotype and genotype occur in other extranodal sites, most commonly in the skin, subcutis, and gastrointestinal tract, and should be referred to as nasal-type T/NK cell lymphomas. The differential diagnosis includes lymphomatoid granulomatosis, blastic or monomorphic NK cell lymphoma/leukemia, CD56-positive peripheral T-cell lymphoma, and enteropathy-associated T-cell lymphoma.

Diagnosis, Differential↗
PubMed1996

Follicular dendritic cell tumor of the liver. Evidence for an Epstein-Barr virus-related clonal proliferation of follicular dendritic cells.

Tumors of the follicular dendritic cell are uncommon, and most occur as primary lymph node tumors. We report a case of primary follicular dendritic cell tumor of the liver that was initially reported as an inflammatory pseudotumor. The neoplasm recurred as two separate tumor masses 30 months after complete resection of the "hepatic inflammatory pseudotumor." It showed a wide spectrum of morphologic features ranging from areas with fascicles of very bland spindle cells amidst a background population of lymphocytes, reminiscent of inflammatory pseudotumor, to areas of dispersed sheets of highly pleomorphic tumor cells with a relative paucity of reactive inflammatory cells. The diagnosis was confirmed by positive immunohistochemical staining with CD21, CD35, R4/23, and Ki-M4 and by ultrastructural demonstration of convoluted interdigitating cell processes joined by desmosomes. The background lymphocytes were oligoclonal, CD8-positive T cells. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNA was positive in the tumor cells in the original and recurrent tumors. More importantly, the cells showed identical episomal clonal EBV on Southern blot analysis, implying that the initial and recurrent tumors are due to clonal proliferation of EBV-positive neoplastic follicular dendritic cells. The tumor cells expressed latent membrane protein but not EBV-encoded nuclear antigen 2 (EBNA2) or ZEBRA. Such gene expression is very similar to that of Hodgkin's disease and nasopharyngeal carcinoma. The strong expression of latent membrane protein restricted to the tumor cells and the clonality of the EBV suggest that the virus may be involved in the pathogenesis of this tumor and not present merely as a "bystander."

Adult↗
PubMed1996

Detection of Epstein-Barr virus-infected mucosal lymphocytes in nasal polyps.

Primary nasal lymphomas of T or NK cell origin are known to be associated with Epstein-Barr virus (EBV). However, it is not known whether EBV is normally present in nasal mucosa as distinct to nasopharyngeal tissue. This study investigates the prevalence of EBV infection in 13 cases of nasal polyps. EBV DNA was detected in 2 of 13 (15%) by Southern blot hybridization and in 9 of 13 (69%) by polymerase chain reaction. In situ hybridization for EBV-encoded small nuclear RNAs (EBER) was positive in 11 of 13 (85%) cases; the virus was present in stromal lymphocytes only and not in the epithelial cells. Immunohistochemistry for EBV proteins in 7 cases revealed EBV nuclear antigen (EBNA)-2, latent membrane protein (LMP)-1, and ZEBRA (the switch protein encoded by gene BZLF1) expression in rare isolated stromal lymphocytes in 3 cases. Double immunostaining in 1 case showed that the LMP-1+ cells were B or T cells. Immunohistochemistry for EBV lytic proteins showed very rare viral capsid antigen (VCA)+ and membrane antigen (MA)+ cells in 1 case and very rare diffuse early antigen (EA-D)+ and VCA+ cells in 1 other case. The expression of ZEBRA, EA-D, VCA, and MA suggested a disruption of latency in very rare stromal lymphocytes leading to a productive cycle. Although the incidence of EBV positivity in nasal polyps in our population is high (85%), very low numbers of EBV+ cells are found in each case. Nevertheless, they indicate that nasal mucosa could be one of the sites of EBV persistence through a low level of infection of the resident lymphocytes and thereby provide a possible setting for the emergence of virally associated tumors in this site.

Adult↗
PubMed1995

Epstein-Barr virus is localized in the tumour cells of nasal lymphomas of NK, T or B cell type.

Seven cases of nasal lymphoma were studied to identify the lineage of Epstein-Barr virus (EBV)+ cells using dual-labelling methods. Five cases were phenotypically and genotypically of natural killer cell (NK) type with germ-line configuration of T-cell receptor (TcR) beta-chain gene and immunoglobulin heavy-chain joining region (IgJH) gene, with one case each of T- and B-cell type showing rearranged TcR beta or IgJH and lambda-light chain genes respectively. EBV genome was clonal in all these cases except in the B-cell case where its clonality was undeterminable. Using in situ hybridization (ISH) for EBV-encoded small nuclear RNA 1 and 2 (EBER), signal was detected in 45% to 88% of nucleated cells in the tumours. Immunostaining for EBV latent membrane protein-I (LMP) also revealed numerous LMP+ cells in 3/5 NK-type cases and the T- and B-cell cases. Using ISH for EBER combined with immunostaining for CD markers and double immunohistochemistry for LMP and CD markers, the predominant lineage of the EBV+ cells was identified as: CD2+CD3-CD19-CD20- CD45R0 +/- CD56+CD68- in the NK-type cases, CD2+CD3 +/- CD19-CD20- CD45R0+CD56-CD68- in the T-cell case and CD20+CD45R0-CD68- in the B-cell case, in agreement with the genotype and phenotype of each tumour. These results show that, in EBV+ nasal lymphomas of NK, T- or B-cell lineage, EBV was consistently associated with the tumour-cell population and support the view that EBV serves a promoting role in the pathogenesis of different types of EBV+ nasal lymphoma.

Adult↗
PubMed1995

Evidence for lytic infection by Epstein-Barr virus in mucosal lymphocytes instead of nasopharyngeal epithelial cells in normal individuals.

Normal nasopharyngeal tissues from 23 individuals who died of causes unrelated to the upper respiratory system and had no evidence of Epstein-Barr virus (EBV)-related diseases were studied using in situ hybridisation (ISH) and immunohistochemistry for the detection of EBV RNA and expression of EBV proteins, respectively. ISH using 35S-labelled riboprobe for EBV EBER RNA showed occasional to a few EBER+ lymphocytes in the stroma of nasopharyngeal mucosa in 14/16 cases with available paraffin-embedded tissues. In addition, very rare intraepithelial EBER+ lymphocytes were also detected in 3/16 cases. However, in none of these cases was EBER detected in the epithelial cells. Similar results were obtained using a nonradioactive ISH method for EBER (Dako). In 3/23 cases, immunostaining using monoclonal antibodies for EBV proteins on cryostat sections showed occasional cells in the stroma expressing EBV nuclear antigen 2 (EBNA2), latent membrane protein-1 (LMP), and switch protein encoded by BZLF1 gene (ZEBRA) in two cases and only very rare LMP+ and ZEBRA+ cells in one other case. Double immunostaining combining alkaline phosphatase anti-alkaline phosphatase (APAAP) for CD markers and indirect immunofluorescence for LMP showed that the LMP+ cells were either CD19+ or less frequently CD3+, but none were CD68+. These results show that both B and T lymphocytes harbouring EBV can be found in the normal nasopharyngeal tissues. Interestingly, EBV proteins associated with lytic viral replication--diffuse early antigen (EA-D), viral capsid antigen (VCA), or membrane antigen (MA)--were also detected in rare cells in the stroma in one case, and in another case only one MA+ cell was detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Treatment outcome and prognostic factors for primary nasal lymphoma.

PURPOSE: To report our experience managing a large series of Chinese patients with primary nasal lymphoma. PATIENTS AND METHODS: From January 1975 to December 1993, 100 patients (median age, 50 years) with newly diagnosed primary nasal lymphoma were studied. There were four low-grade, 62 intermediate-grade, nine high-grade, and 25 unclassifiable lymphomas. Immunophenotyping was performed in 45 patients: eight B cell, 35 T cell, and two uncertain. All cases of angiocentric lymphoma that were typed were T cell. Fifty-two patients had stage I disease, 15 had stage II, four had stage III, and 29 had stage IV. Only 15 patients had B symptoms (weight loss, night sweats, and/or fever), and 11 had bulky disease. Thirty-nine patients with clinically localized stage I and II disease received local radiotherapy alone (before 1980), and the remaining 28 stage I and II patients received combination chemotherapy followed by local radiotherapy. The 33 patients with advanced stage III and IV disease were given combination chemotherapy, and additional radiotherapy was given to five of them who had bulky local disease. RESULTS: Significantly higher complete remission rates were observed in patients with early stages of disease and those without B symptoms. Superior disease-free survival after complete remission was observed in patients with stage I/II disease. Univariate factors associated with a better overall survival included age less than 60 years, stage I disease, and absence of B symptoms. Survival was significantly better in the subgroup of patients with stage I disease. CONCLUSION: Patients with nasal lymphoma, especially those with advanced disease, seemed to have a poor prognosis, and their clinical outcome was not improved significantly by the use of chemotherapy instead of radiotherapy or the use of doxorubicin-containing chemotherapeutic regimens.

Adolescent↗
PubMed1994

Epstein-Barr virus (EBV)-related lymphoproliferative disorder with subsequent EBV-negative T-cell lymphoma.

A 58-year-old Chinese man presented initially with generalized lymphadenopathy, and lymph-node biopsy showed disturbed architecture with preponderance of large B-blasts mixed with numerous CD8+ T lymphocytes, consistent with an acute Epstein-Barr virus (EBV) infection. Immunohistological and gene rearrangement studies confirmed the absence of clonal T or B cells. Polyclonal EBV with lytic infection was detected by Southern blot hybridization (SoBH). Expression of EBV proteins (EBNA2, LMP and ZEBRA) was detected in a proportion of cells by immunostaining. EBV-lytic proteins EA-D, VCA, MA were also detected in rare scattered cells. Double immunostaining showed that the LMP-positive cells were of B and of T phenotype: 73% CD19+, 26% CD2+, 23% CD3+, 8% CD4+, 17% CD8+. After biopsy, there was spontaneous regression of lymph-node enlargement, but lymphadenopathy recurred 8 months later, and the second lymph-node biopsy showed T-cell lymphoma, confirmed by detection of clonally rearranged T-cell-receptor beta-chain gene. However, EBV genome could not be detected in the second biopsy by SoBH, in situ hybridization for EBV-encoded EBER RNA, and immunostaining for EBNA2, LMP and ZEBRA was also negative. This case is of special interest because an EBV-negative T-cell lymphoma developed shortly after an acute episode of EBV-related lymphoproliferation, even though many EBV-positive T cells were detected during the acute episode. EBV was apparently not a direct cause of the lymphoma, but the close temporal association of the 2 lesions supports the hypothesis that EBV can act as a co-factor in lymphomagenesis.

Gene Rearrangement↗
PubMed1994

Anti-oral microbial activity of isoflavonoids in root bark of Ormosia monosperma.

From the root bark of Ormosia monosperma, 10 isoflavonoids including two new compounds 7,4'-dihydroxy-6",6"-dimethylpyrano-(2",3":5,6)-8-(3-methyl-1,3- butadienyl)isoflavone, named ormosidin, and dalbergion 4'-O-beta-D-glucopyranoside, were isolated. These structures were confirmed by spectroscopic analysis. 2,3-Dihydroauriculatin, one of the compounds isolated, showed moderate activities against oral-microbial organisms (Streptococcus mutans, Prophyromonas gingivalis and Actinomyces actinomycetemcomitans).

Anti-Infective Agents↗
PubMed1994

Evaluation of a histogenetic classification for thymic epithelial tumours.

We reviewed 87 thymic epithelial tumours from Chinese patients and typed them according to the Marino and Müller-Hermelink classification as updated by Kirschner and Müller-Hermelink in 1989. Related categories were grouped for statistical analyses: group 1, medullary thymoma and mixed thymoma; group 2, cortical predominant thymoma; group 3, cortical thymoma and well-differentiated thymic carcinoma; group 4, other thymic carcinomas; and group 5, unclassified. Group 3 tumours were more frequently associated with the myasthenia gravis syndrome compared with group 1 tumours (P = 0.001). They also presented at a more advanced stage. Groups 1 and 2 showed an excellent prognosis (100% survival at 10 years). The 10-year survival for groups 3 and 4 patients was 40% and 30% respectively. Pure medullary thymoma made up a higher proportion of our cases (10.3%) than those of a similar Caucasian study (5.3%). The eight thymic carcinomas (group 4) included two thymic lymphoepitheliomas. We conclude that the histogenetic classification evaluated shows a clear correlation with prognosis and clinical features, even when tested on separate geographic groups, where pathogenetic factors may be different. A common approach to classification of thymic epithelial tumours would greatly facilitate future studies on these possible differences.

Adult↗
PubMed1994

Immunohistochemical demonstration of c-erbB-2 oncoprotein in gastric adenocarcinoma: comparison of cryostat and paraffin wax sections and effect of fixation.

AIMS: To investigate the effects of fixation on the immunohistochemical demonstration of c-erbB-2 oncoprotein using paraffin wax and cryostat sections; to compare c-erbB-2 expression in non-neoplastic and neoplastic gastric tissues. METHODS: Adjacent blocks of tumour and non-neoplastic tissue from four gastrectomy specimens were put into a panel of 10 fixatives including acetone, B5, Bouin's fluid, Carnoy's fluid, buffered formalin, formol dichromate, zinc formalin, 4% paraformaldehyde, periodate-lysine-paraformaldehyde (PLP) and periodate-lysine-paraformaldehyde-dichromate (PLPD) before embedding in paraffin wax for sectioning. Similar tissue blocks were snap frozen and cryostat sections were postfixed in these fixatives, either alone or in combination, before immunostaining. RESULTS: In paraffin wax embedded sections the best fixative was PLP, and in frozen tissues the best results were obtained after fixation of cryostat sections in buffered formalin followed by cold methanol and acetone. Applying these fixatives to samples from a further 16 gastrectomy specimens, strong membrane staining of c-erbB-2 protein was found in the tumour in eight of 16 cases (50%) using paraffin wax sections, and staining was stronger in the better differentiated carcinomas. For frozen tissues, positive membrane staining was found in all gastric adenocarcinomas, but differential staining intensity associated with tumour differentiation could not be detected. CONCLUSIONS: These results indicate that fixation and paraffin wax embedding affect the results of immunohistochemical demonstration of c-erbB-2 in gastric cancer. The choice of fixative is critical in the demonstration and evaluation of c-erbB-2 protein expression by immunohistochemistry in gastric carcinomas. Staining results also vary depending on whether frozen or paraffin wax embedded tissues are studied.

Adenocarcinoma↗
PubMed1994

Lack of correlation between expression of Epstein-Barr virus (EBV) latent membrane protein and bcl-2 oncoprotein in vivo.

AIMS: To evaluate whether there is any correlation between the expression of Epstein-Barr virus (EBV) latent membrane protein (LMP) and oncoprotein bcl-2 in the lymph node biopsy specimens of a Chinese patient with EBV-related reactive lymphoproliferation who later developed T cell lymphoma after a short period of time. METHODS: Immunohistochemistry, with a standard alkaline phosphatase antialkaline phosphatase (APAAP) method and New Fuchsin as a chromogen, was used for single staining of bcl-2 or LMP. Double immunostaining combining APAAP and indirect immunofluorescence was performed for dual labelling of LMP and bcl-2. RESULTS: bcl-2 was expressed in 10-30% of cells in the first lymph node biopsy specimen (EBV-associated lymphoproliferative disorder) and 30-50% of cells in the second lymph node biopsy specimen (T cell lymphoma). LMP was expressed in the first biopsy specimen but not in the second. Double immunostaining results showed that around 78% of LMP positive cells were bcl-2 negative and 94% bcl-2 positive cells were LMP negative. Among the very small fraction of LMP and bcl-2 double positive cells, the intensity of bcl-2 staining was heterogeneous and was not always stronger than that observed in LMP negative bcl-2 positive cells. CONCLUSIONS: The expression of bcl-2 protein is independent of LMP protein status in vivo. Several mechanisms may be involved in EBV associated lymphomagenesis, and bcl-2 induction may occur independently of LMP expression.

Fluorescent Antibody Technique↗
PubMed1994

Improved double immunohistochemical staining method for cryostat and paraffin wax sections, combining alkaline phosphatase anti-alkaline phosphatase and indirect immunofluorescence.

AIMS: To develop and immunohistochemical staining method for cryostat and paraffin wax sections so that two different antigens in the same section of tissues could be detected by combining immunoenzyme and immunofluorescence techniques. METHODS: This double immunohistochemical staining method combines alkaline phosphatase-anti-alkaline phosphatase (APAAP) using New Fuchsin as a chromogen and indirect immunofluorescence. RESULTS: APAAP staining for one antigen of this double immunohistochemical staining method was observed under bright field conditions alternating with immunofluorescence for another antigen under ultraviolet light. The double exposed photograph of both easily identified the two signals within the same cell. CONCLUSIONS: This double immunohistochemical staining method can overcome the disadvantages of any masking effect of the double immunoenzymatic methods and the background problems of double immunofluorescence method especially when applied to paraffin wax sections. It also permits good morphological identification of the doubly stained cells which may be of crucial importance in studies on pathology specimens.

Alkaline Phosphatase↗
PubMed1993

Latent sites of Epstein-Barr virus infection.

Epstein-Barr virus (EBV) has been detected in a wide spectrum of tumors. This study investigates the detection rate of EBV-DNA by Southern blot hybridization analysis (SOBH) and polymerase chain reaction (PCR) in different tissues from persons without apparent EBV-related diseases. Of 20 tonsillectomy specimens studied, SOBH indicated positivity for EBV-DNA in 1 case, and PCR indicated positivity in 10. In autopsies performed on patients with no apparent evidence of EBV-related diseases, the viral DNA was only detected by PCR in the following: parotid gland (7/15), submandibular gland (8/20), nasopharynx (8/10), tonsil (8/10), larynx (5/6), lung (5/9), cervical lymph node (7/10), mediastinal lymph node (7/10), abdominal lymph node (4/10), spleen (6/10), thyroid (5/10), liver (1/10), pancreas (1/4), kidney (4/10), uterine cervix (1/4), ovary (1/5) and testis (1/3). These results provide a baseline for interpreting the role of EBV in carcinogenesis.

Adolescent↗
PubMed1993

Usefulness of follicular dendritic cell pattern in classification of peripheral T-cell lymphomas.

Classification of peripheral T-cell lymphomas based on morphological criteria can present problems due to overlap in histological features amongst the subtypes. An immunohistochemical study was designed to study the follicular dendritic cell patterns in 21 cases of peripheral T-cell lymphoma which had been classified using the updated Kiel classification. Three patterns of distribution were observed: 1 follicular dendritic cells not detected (3 cases); 2 follicular dendritic cells restricted to remnant follicle centres (7); 3 follicular dendritic cells present as an expanded network of cells exceeding the confines of germinal centres (11). Ten out of 11 angioimmunoblastic lymphomas showed an expanded network of follicular dendritic cells. The only negative case showed features which, on review, were in keeping with a pleomorphic, medium and large cell lymphoma showing an unusual proliferation of small venules. Other than angioimmunoblastic lymphomas, only one other case showed follicular dendritic cell hyperplasia. This was an unclassified peripheral T-cell lymphoma. We conclude that follicular dendritic cell hyperplasia may be used an an aid to diagnosis of the angioimmunoblastic type of peripheral T-cell lymphoma, and we recommend the routine staining of these cells in typing of T-cell lymphomas to facilitate comparison between centres.

Antibodies, Monoclonal↗