Biomedical subjects

J S Sham

Publications and source records attributed to J S Sham.

At least 109 records · Page 6Linked to original sources

PubMed1991

The efficacy of fiberoptic endoscopic examination and biopsy in the detection of early nasopharyngeal carcinoma.

Fiberoptic endoscopic examination and biopsy of the nasopharynx was done in 130 patients as a prospective study. They all had elevated titers of antibodies against the viral capsid antigen of Epstein-Barr virus but no symptoms or signs of nasopharyngeal carcinoma. Each underwent a biopsy from six fixed sites in the nasopharynx. Of the 780 biopsy specimens taken from seven patients, 11 showed the presence of nasopharyngeal carcinoma. Techniques to improve the yields of such biopsies with fiberoptic endoscopy are discussed. The presence of tumor was unrelated to the macroscopic endoscopic findings. The highest incidence of subclinical tumor is in the pharyngeal recess.

Adult↗

PubMed1991

Role of bone scanning in detection of subclinical bone metastasis in nasopharyngeal carcinoma.

One hundred thirty-two new patients with nasopharyngeal carcinoma and no evidence of distant metastases were evaluated for bone metastases with bone scanning. Forty-four patients had abnormal hypercaptation. These abnormal findings were considered related to benign diseases in 39 patients after correlating clinical examinations and skeletal radiographs. The remaining five patients had positive bone scanning which was suggestive of bone metastasis. There were 13 patients who developed symptomatic bone metastases over a follow-up period of 0.2-41 months. In three of these, the bone metastases corresponded to the sites of abnormal hypercaptation in the initial positive bone scanning. In view of the low sensitivity and specificity of bone scanning in this setting, routine bone scanning for staging nasopharyngeal carcinoma is not recommended. But in the research setting, baseline scanning is useful to make subsequent scanning more valuable, and it reduces false-positive results.

Bone Neoplasms↗

PubMed1991

The cytological diagnosis of nasopharyngeal carcinoma using a silk swab stick.

A prospective study was carried out to investigate the efficacy of exfoliative cytology for the diagnosis of nasopharyngeal carcinoma. Exfoliated nasopharyngeal cells were collected from patients with a clinical suspicion of carcinoma by scraping the nasopharyngeal mucosa with a piece of silk wrapped around one end of a wooden stick. Ninety-eight patients were investigated in this manner, and the results of cytological investigation compared with the histological findings. The sensitivity of cytological investigation was 71% and the overall accuracy was 86%. The combined use of cytology and serology as a method of screening for nasopharyngeal carcinomas is discussed.

Adolescent↗

PubMed1991

Nasopharyngeal carcinoma: treatment of neck node recurrence by radiotherapy.

The records of 91 nasopharyngeal carcinoma patients who were treated with external radiotherapy for recurrent neck node disease were reviewed. All patients had received prior radiotherapy for cervical nodal disease or prophylactic neck irradiation. The node size (product of the greatest perpendicular diameters) at the time of treatment for nodal relapse ranged from 1cm2 to 35cm2 (median 2.25cm2). The radiation dose ranged from 823 RETs to 1949 RETs (median 1520 RETs). The recurrent node size and radiation dose were found significant prognostic factors for local control. The local tumour control for nodes 4cm2 or smaller was 51% at five years, for nodes greater than 4cm2 was 16% at 18 months (p = 0.01). The overall 5 year survival was 19.7%. Radiation dose greater than 1600 RETs was significantly associated with better survival for patients with recurrent nodes measured 4cm2 or smaller, but higher radiation dose did not improve the survival of patients with recurrent nodes greater than 4cm2. Because of the dilemma of suboptimal control resulting from inadequate radiation dose when compared with surgical treatment, and possible radiation complication from higher dose, surgery should be the treatment of choice for neck node recurrence after primary radiotherapy for nasopharyngeal carcinoma.

Carcinoma↗

PubMed1991

Radical neck dissection in nasopharyngeal carcinoma.

We report a series of 37 patients who had radical neck dissection for residual or recurrent lymph node metastasis from nasopharyngeal carcinoma after radiotherapy. The operation was performed despite high doses of pre-operative radiotherapy. There was no operative mortality and the morbidity was 13% (2 prolonged chylous drainage, 3 sloughing of neck flap). The risk of sloughing of neck flap was significantly related to previous lymph node biopsy, which should be avoided if at all possible. In 35% of patients, the lymph node was densely adherent to neighbouring structures. In the 28 patients who had single lymph node clinically, 29% had multiple neck node involvement noted during operation; another 14% were documented only on histological examination. Radical neck dissection rather than excision alone is justified for the clinically solitary lymph node.

Adult↗

PubMed1991

Phospholamban mediates the beta-adrenergic-enhanced Ca2+ uptake in mammalian ventricular myocytes.

To probe the molecular mechanism responsible for the relaxant effect of catecholamines in heart muscle, we studied the effect of a monoclonal antibody (2D12) against phospholamban in intact whole cell clamped guinea pig ventricular myocytes, in which intracellular Ca2+ transient and Ca2+ current were simultaneously measured. The antibody stimulated Ca2+ uptake in guinea pig ventricular sarcoplasmic reticular vesicles, shifting the apparent dissociation constant for activation by Ca2+ from 200 to 60 nM. The stimulatory effect of the antibody could be mimicked by the catalytic subunit of adenosine 3',5'-cyclic monophosphate-dependent kinase and could be blocked by phospholamban peptide 2-25. Dialysis of ventricular myocytes with the antibody enhanced the rate of uptake of Ca2+ and significantly suppressed the ability of isoproterenol to enhance the rate of uptake and release of Ca2+ by depolarizing pulses. These data suggest that not only is phosphorylation of phospholamban crucial in sequestration of Ca2+ by the sarcoplasmic reticulum, but that this process may account for the catecholamine-enhanced rate of Ca2+ uptake release in heart muscle.

Adrenergic beta-Agonists↗

PubMed1991

Nasopharyngeal carcinoma and lymphoinfiltration.

Originally referred to as 'lymphoepithelioma', undifferentiated and poorly differentiated nasopharyngeal carcinoma (NPC) tissues showed intense lymphoinfiltration. In a study of cryosections from 15 NPC tissues, we found that infiltrating lymphoid elements were comprised predominantly of lymphocytes, but plasma cells, follicular dendritic cells, and eosinophils were also commonly seen. Subpopulations of lymphocytes having the same phenotypes tend to aggregate, forming clusters or secondary follicles in stromatous tissues. The tumor areas were mainly infiltrated by T cells. Tumor cells and/or apparently normal epithelium in the paratumorous areas frequently expressed CD21, CD23, CD40 and a B lymphocytes carcinoma cross-reacting antigen (BLCa), all of which are involved in B cell activation and proliferation. CD21 and BLCa were strongly expressed near the surface of both squamous and columnar epithelium by those epithelial cells which are at advanced stage of differentiation, while CD40 was expressed by epithelial cells at earlier stages of differentiation located at or near the basement membrane. CD23 was mainly expressed by columnar cells and basal cells underlying squamous epithelium, but not, or weakly so, by flattened squamous cells or reserve cells underlying columnar epithelium. The large majority of tumor cells expressed CD40 and BLCa. A substantial proportion of them also expressed CD23, but the tumor cells were not reactive for CD21. Despite eosinophilic infiltration, IL-6 was not detected in tumor tissues. IL-1 was, however, detected in abundance in the cytoplasm of follicular dendritic-like cells and in the intercellular spaces in tumor areas and surrounding stromatous tissues. The immunobiology of NPC is discussed in the light of these observations.

Antibodies, Monoclonal↗

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

Choroid metastasis from nasopharyngeal carcinoma.

A case of choroid metastasis from nasopharyngeal carcinoma (NPC) is presented. If loss of vision in patients with NPC is not associated with proptosis or weakness of the extra-ocular eye muscles after radiotherapy, investigations to exclude choroid metastasis should be carried out. Choroid metastasis, in contrast to the more common causes of loss of vision in such a situation, radiation retinopathy and optic neuropathy, is amenable to treatment to prevent irreversible blindness and enucleation for intractable glaucoma pain.

Adult↗

PubMed1991

Breast metastasis from nasopharyngeal carcinoma.

The first two cases of breast metastases from anaplastic carcinoma of the nasopharynx are presented. In both cases the breast metastasis was solitary, but there was no delay in confirming their metastatic nature since both lesions manifested after the documentation of disseminated disease. The difference in histology, since 99% of our nasopharyngeal carcinoma patients have anaplastic carcinoma of poorly differentiated carcinoma subtype, makes it easy to differentiate them from primary breast cancer by cytology or histology.

Adult↗

PubMed1990

Osteosarcoma of the maxilla in Hong Kong Chinese postirradiation for nasopharyngeal carcinoma. A report of four cases.

Postirradiation osteosarcoma of the maxilla was seen in four Hong Kong Chinese patients treated for nasopharyngeal carcinoma. These cases represent four of 42 (9%) cases of osteosarcoma at all sites in this institution during the period 1979 to 1989, when more than 1000 patients were treated with radiotherapy for nasopharyngeal carcinoma. The latent periods varied from 8 to 11 years from completion of radiotherapy treatment to development of osteosarcoma. The radiation dosage varied from 6000 to 6280 cGy in three of the patients. These cases fit the criteria for diagnosis of postirradiation sarcomas. Maxillary osteosarcomas after irradiation for nasopharyngeal carcinoma do not appear to have been described. The very high incidence of nasopharyngeal carcinoma (for which radiotherapy is the treatment of choice) in Hong Kong Chinese would make the occurrence of such tumors more likely in Hong Kong, although the small risk does not contraindicate the use of radiation in the treatment of nasopharyngeal carcinoma in view of its well-documented efficacy.

Adult↗

PubMed1990

Nasopharyngeal carcinoma in young patients.

Seventy-one Chinese patients ranging in age from 9 to 20 years who had histologically verified nasopharyngeal carcinoma were reviewed. The presenting symptoms were often multiple, comprising nasal (77.5%) and ear (73.2%) symptoms, headache (60.6%), and neck swelling (63.4%). The median duration of these symptoms was 2 to 3 months, and 90.1% of the patients were Stage III or IV at presentation. All patients were treated primarily by radiotherapy. Forty-four of the 71 patients died of the disease; the median time to death was 18 months. Nasopharyngeal carcinoma in the young patients in Hong Kong does not appear to be different from that of the adult population in Hong Kong in terms of histology, pattern of relapse, and survival. Compared with the adult patients, however, the current series of young patients presented with more advanced-staged disease. The incidence of nasopharyngeal carcinoma in Hong Kong was compared with Chinese populations in other parts of the world, and the general pattern was comparable. The only postadolescent peak was found in the Chinese population of San Francisco.

Adolescent↗

PubMed1990

Detection of subclinical nasopharyngeal carcinoma by fibreoptic endoscopy and multiple biopsy.

Of 6054 people who had high titres of antibodies against the viral capsid antigen of Epstein-Barr virus but no symptoms or signs of nasopharyngeal carcinoma as assessed by conventional methods, 130 were randomly recruited and examined by fibreoptic endoscopy and biopsy of several sites of the nasopharynx. 7 cases of nasopharyngeal carcinoma were detected. The tumours were largely confined to the pharyngeal recess, which suggests that it is the area of the nasopharynx most prone to the development of the tumour. Tumour was found in both recesses in 1 subject, who also had evidence of transition from severe epithelial dysplasia to carcinoma in a sample from the left roof, which suggests that the disease was multifocal in origin. This study showed that endoscopy and biopsy of several sites of the nasopharynx are more effective than the conventional approach in the detection of subclinical nasopharyngeal carcinoma among seropositive individuals at high risk of the disorder.

Adult↗

PubMed1990

Nasopharyngeal carcinoma. Pattern of tumor regression after radiotherapy.

The primary tumor regression pattern of 50 patients with nasopharyngeal carcinoma was reported. The tumor regression was monitored either by indirect nasopharyngeal mirror examination and biopsy or fiberoptic endoscope and biopsy. Fiberoptic endoscope and biopsy was found to be more accurate in noting residual tumor. It is recommended that booster radiation dose to the residual primary tumors be withheld unless positive biopsy samples persist at 10 or more weeks after radiotherapy.

Biopsy↗

PubMed1990

Split-palate approach for gold grain implantation in nasopharyngeal carcinoma.

Although nasopharyngeal carcinoma is radiosensitive, local failure after external radiotherapy is not uncommon and management of persistent or recurrent disease is a therapeutic challenge. The present review reports the use of brachy-therapy in the form of gold grain (198Au) implants in the treatment of 23 patients with recurrent or persistent primary nasopharyngeal carcinoma. The split-palate approach was employed in the insertion of the gold grains. This approach allows adequate exposure of the nasopharynx and accurate positioning of the implants. Implantation was successful in 21 patients, and local tumor control was achieved in 17 patients (81%) after a median follow-up of 23 months. Palatal fistula developed in 6 patients (26%): 5 healed with conservative management, and 1 had no functional disturbance. There was no operative mortality, and morbidity of the operation was minimal.

Brachytherapy↗

PubMed1990

Efficacy of fine-needle aspiration and sampling of lymph nodes in 1,484 Chinese patients.

A retrospective study of 1,855 fine-needle aspirations of the lymph node (LN) from 1,484 Chinese patients in Queen Mary Hospital over a period of 11.5 yr (January 1, 1976, to June 30, 1987) was reviewed and analyzed. Positive cytologic results diagnosed malignancies in 49.3%. Sensitivity and specificity of cytology reached 95% and 96.5%, respectively. The order of frequency of the metastatic tumors according to primary sites was analyzed. The most common metastatic carcinomas in various groups of LNs were nasopharyngeal carcinoma in the cervical LN, breast carcinoma in the axillary LN, and cervical carcinoma in both the groin and pelvic LNs. Tuberculosis (TB) is an important differential diagnosis; FNAC showed a sensitivity of 76.9% in the detection of TB lymphadenopathy.

Adolescent↗

PubMed1990

Nasopharyngeal carcinoma: orderly neck node spread.

A prospective study of 271 consecutive patients with newly diagnosed nasopharyngeal carcinoma was undertaken to assess the pattern of cervical nodal involvement with reference to 10 cervical nodal groups and three levels of neck; 204 (75.3%) patients were found to have cervical lymphadenopathy at presentation. Fifty-four (26.5%) of these patients had right cervical lymphadenopathy, 70 (34.3%) had left cervical lymphadenopathy, and 80 (39.2%) had bilateral cervical lymphadenopathy. The occurrence of lymphadenopathy in the 10 cervical nodal groups and the mean size of nodes in these nodal groups were computed. The subdigastric and upper jugular group was involved in more than 95% of cases. The lower the position in the neck, the less frequently the nodal group was involved. The mean size of nodes was largest in the subdigastric and upper jugular region compared with the other groups. The nodes in the upper neck were generally larger than those in the lower neck. The lower two levels of neck were involved without involvement of the upper level of the ipsilateral neck in fewer than 4% of cases. The present study indicates that neck node involvement by nasopharyngeal carcinoma is by orderly spread down the neck, which explains the adverse prognostic significance of neck node involvement in the lower neck. The orderly involvement of the neck nodes suggests that prophylactic irradiation of the neck should be given at least one level beyond the clinical extent of disease, which for patients with no clinically palpable node would mean prophylactic irradiation of the upper neck.

Head and Neck Neoplasms↗

PubMed1990

Efficacy of radical neck dissection for the control of cervical metastasis after radiotherapy for nasopharyngeal carcinoma.

Fifty-one patients who had persistent or recurrent neck disease from nasopharyngeal carcinoma after radiotherapy underwent radical neck dissection. The follow-up period ranged from 0.5 to 9 years (median: 2 years). Multiple cervical lymph node involvement was present in 51% of the patients (26 of 51). Malignant cells were detected in 88% of the resected specimens (45 of 51). The clinical sign of fixation of lymph node is the only factor that affects the successful control of neck disease (p = 0.04). Extracapsular extension of the nodal disease was present, and 35% of the lymph nodes were adherent to surrounding structures at operation (18 of 51). There was one hospital mortality and the overall morbidity was minimal. The actuarial survival at 5 years was 38%, and the probability of control of neck disease was 66%. Radical neck dissection is effective in controlling post-irradiation cervical metastasis from nasopharyngeal carcinoma.

Adult↗