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Biomedical subjects

W K Ng

Publications and source records attributed to W K Ng.

At least 37 records · Page 2Linked to original sources
PubMed1998

Raised serum hCG in a male patient caused by primary jejunal choriocarcinoma.

A rare case of primary choriocarcinoma of the jejunum occurred in a 45 year old Chinese man. This tumour was associated with massive melaena and a markedly raised serum human chorionic gonadotrophin (beta-hCG) concentration. Necropsy examination showed no primary lesion in other possible sites including testes, mediastinum, and pineal gland. Histologically, the tumour showed morphology typical of choriocarcinoma with no adenocarcinomatous element identified. The presence of choriocarcinoma in non-gonadal sites may be explained by retrodifferentiation or metaplasia of a conventional carcinomatous component to primitive trophoblasts. Serum beta-hCG level may represent a useful marker in earlier diagnosis and monitoring of this potentially treatable disease.

Biomarkers, Tumor↗
PubMed1997

Diagnostic significance and possible pitfalls of nuclear grooves in extrathyroid cytology.

The diagnostic significance of grooved nuclei in the cytology of extrathyroid lesions is not well-described in the literature. Isolated cases of metastatic adult granulosa cell tumor, reactive mesothelial hyperplasia, Langerhans' cell histiocytosis, recurrent renal cell carcinoma, and round cell liposarcoma were reviewed, and their cytologic features were discussed. While nuclear grooving can be present to a different extent in all these conditions, the significance of this feature in diagnostic cytology varies. The integration of clinical information, radiologic findings, different morphologic features, and immunohistochemistry is necessary before a final conclusion is reached.

Adolescent↗
PubMed1997

Cutaneous epithelioid angiosarcoma: a potential diagnostic trap for cytopathologists.

We report on the cytologic features of a rare case of cutaneous epithelioid angiosarcoma of the scalp occurring in a 65-yr-old Chinese male. The prominent epithelioid features may cytologically mimic poorly-differentiated carcinoma, malignant melanoma, and even epithelioid sarcoma. Recognition of subtle cytologic features of vasoproliferation, immunohistochemical demonstration of endothelial markers, and ultrastructural examination are necessary before a final conclusion may be drawn.

Aged↗
PubMed1997

Coronary revascularisation in young adults.

OBJECTIVE: To evaluate the long-term outcome of coronary artery bypass surgery (CABG) in patients < 40 years old and to determine factors predictive of adverse outcomes. METHODS: Retrospective review of data on 220 patients who underwent isolated CABG at Green Lane Hospital, New Zealand from 1970 to 1992. RESULTS: The actuarial survival after surgery was 91, 74 and 50% at 5, 10 and 15 years, respectively. Recurrence of ischaemic symptoms occurred at a median time of 72 months, and only 20% of patients remained asymptomatic 10 years after CABG. Univariate analysis of potentially adverse surgical factors showed that patients who had prolonged bypass time (> or = 100 min, P < 0.007) had increased late mortality. There were two distinct operative eras with respect to the use of IMA conduits (4% pre 1985, 87% post 1984) The relationship between IMA conduits use and survival was significant on time independent analysis (P < 0.02), but was not using the log-rank test. Preoperative clinical characteristics associated with increased late mortality were impaired left ventricular function (end-systolic volume (ESV) > or = 80 ml, P = 0.008; ejection fraction < 40%, P = 0.0005), and lack of aspirin use either pre- or post-operatively (P < 0.0001). Multivariate analysis indicated that reduced ejection fraction (P = 0.04) and prolonged bypass time (P = 0.05) was associated with an increased risk of late death. Aspirin therapy (P = 0.001) was associated with decreased late mortality. Cumulative events rate of reintervention and mortality was reduced in female patients (P = 0.0009). At review, 45% of patients had total cholesterol > 6.5 mmol/l. CONCLUSION: To avoid the early recurrence of symptoms, the need for reintervention and late mortality, young patients should receive IMA conduits, cardioplegia as myocardial protection, aspirin and therapy to modify/ameliorate their risk factors including dyslipidaemia, diabetes and left ventricular dysfunction.

Actuarial Analysis↗
PubMed1997

Chromic oxide inclusion in the diet does not affect glucose utilization or chromium retention by channel catfish, Ictalurus punctatus.

This study was conducted to determine if the level of dietary chromic oxide will affect glucose utilization and tissue chromium retention by channel catfish. Purified diets containing graded levels of supplemental chromic oxide (0, 50, 100, 200, 400, 1000, 5000 and 10,000 mg/kg diet) and glucose as the carbohydrate source were fed to channel catfish fingerlings for 10 wk. Another diet containing dextrin as the carbohydrate source and without chromic oxide supplementation was also fed and served as the control diet. Fish fed the dextrin diet had significantly (P < 0.05) greater weight gain, feed efficiency ratio and protein efficiency ratio but lower plasma glucose concentrations than fish fed the glucose diets irrespective of the level of chromic oxide supplementation. The growth performance and postprandial plasma glucose concentrations of channel catfish fed glucose diets supplemented with various chromic oxide levels were not significantly different. No obvious trends were observed in the whole-body composition of fish fed glucose diets containing various chromic oxide levels. Carbohydrate source or the level of dietary chromic oxide did not significantly affect chromium concentrations in the whole-fish carcass. These results suggest that the level of dietary chromic oxide had no significant effect on glucose utilization or chromium retention by channel catfish. It is suggested that chromic oxide is sufficiently inert to be used as an external marker in digestibility studies in channel catfish.

Animals↗
PubMed1997

A technique of acrylic nail fixation in multilayered silicone finger prostheses.

A technique for the secure fixation of acrylic nails in multilayered silicone finger prostheses is described. The secure fixation of the nail to the prosthesis is achieved by a method of "sandwiching" portions of the nail between the silicone layers of the prosthesis akin to the overlapping of the nail by the anatomical nail fold and nail wall. In addition the use of a cynoacrylate adhesive ensures strong surface to surface bonding.

Acrylic Resins↗
PubMed1996

Cytologic Diagnosis of "CASTLE" of thyroid gland: report of a case with histologic correlation.

We report on the cytologic and histologic features of a rare form of lymphoepithelioma-like carcinoma of the thyroid i.e., carcinoma showing thymus-like element (CASTLE). Sixteen cases of cervical lymph node aspirates with metastatic nasopharyngeal carcinoma are also reviewed. While it is important to recognize CASTLE of the thyroid because of its distinctly good prognosis, its cytologic features closely resemble those in metastatic nasopharyngeal carcinoma.

Adult↗
PubMed1996

Crescentic nodular glomerulosclerosis secondary to truncated immunoglobulin alpha heavy chain deposition.

Nodular glomerulosclerosis secondary to deposition of monoclonal immunoglobulin (Ig) light chains with or without heavy chains is a recognized clinicopathological entity. Recent reports have demonstrated that an identical glomerular lesion may also occur as a result of truncated tau Ig heavy chain deposition. We investigated the nature of Ig deposits in a patient who presented with rapidly progressive renal failure secondary to crescentic nodular glomerulosclerosis. This patient had a relapsing clinical course responsive to treatment with steroid and cyclophosphamide therapy. In this case, both the glomeruli and tubular basement membrane contained granular immune deposits that were reactive to polyclonal antibodies against alpha but not tau or mu Ig heavy chains and nonreactive to anti-kappa and anti-lambda light chain reagents. A monoclonal population of plasma cells secreting alpha and kappa chains was present in the patient's marrow despite the finding of a normal percentage of plasma cells. Serum Immunoelectrophoresis was normal, but immunofixation demonstrated the presence of a monoclonal alpha/kappa band. Immunoblot under dissociating and nondissociating conditions showed that both the patient's urine and serum contained Ig fragments that comprised dimer or monomer of an abnormally short alpha Ig heavy chain (approximately 26 kd) with or without associated kappa light chain. The identity of the abnormal serum alpha Ig heavy chain with that of the glomerular Ig deposits was supported by the finding that both were nonreactive against alpha 1 and alpha 2 subclass-specific monoclonal antibodies despite their reactivity to polyclonal antibodies. Because these monoclonal antibodies would react with structural determinants, which differ between alpha 1 and alpha 2 Ig heavy chains but not those common between them, and because the differences in amino acid sequence between the two largely lie in the CH1 and CH2 domains of the alpha Ig heavy chain, it is hypothesized that the abnormally short alpha Ig heavy chain produced by plasma cells in this patient contains deleted CH1 and CH2 domains similar to the findings in patients with tau Ig heavy chain deposition disease.

Biopsy↗
PubMed1996

Collision tumour of the oesophagus: a challenge for histological diagnosis.

An unusual case of mantle cell lymphoma metastasising to squamous cell carcinoma of the oesophagus, in a 62 year old Chinese man, is reported. A histological diagnosis based on examination of a small endoscopic biopsy specimen, in the absence of detailed clinical information, may be difficult, as the lymphoma component can be mistaken for reactive lymphoid infiltrate which is sometimes present adjacent to squamous cell carcinoma. Correlation with the clinical history, careful assessment of the subtle histological changes, and use of ancillary methods such as immunohistochemistry are most helpful in making the correct diagnosis. This case also illustrates further the possible occurrence of lymphomatous infiltrates surrounding other lesions in patients with a previous or concurrent history of lymphoma.

Carcinoma, Squamous Cell↗
PubMed1996

Spinal dural arteriovenous malformation: a cause of myelopathy.

Spinal vascular malformation is an uncommon but potentially treatable cause of myelopathy. We describe two cases of angiographically proven spinal vascular malformation in Malaysia. The first case is a 47-year-old man who had a progressive myelopathy and the second a 60-year-old man with intermittent attacks of transient paraparesis leading to paraplegia. As the clinical presentation of spinal vascular malformation is variable, it should be considered as a cause of patients with myelopathy.

Angiography↗
PubMed1995

Langerhans' cell histiocytosis: possible association with malignant germ cell tumour.

A rare case of adult onset Langerhans' cell histiocytosis associated with dysgerminoma in a 35 year old Chinese woman is reported. The patient had a history of dysgerminoma of left ovary 15 years previously and had undergone surgery followed by radiotherapy and an uneventful recovery. She presented again in March 1994, this time with a left clavicular mass, which was shown histologically to be Langerhans' cell histiocytosis. The report illustrates the probable association between the two lesions, with some discussion on the underlying pathogenesis.

Adult↗
PubMed1995

Elevated serum alpha-fetoprotein in a patient with undifferentiated carcinoma of the gall bladder.

An uncommon case of undifferentiated carcinoma of the gall bladder in a 65 year old Chinese man, who presented with an increased serum alpha-fetoprotein concentration, is reported. Histologically, the tumour had a primitive appearance and was composed of a pavement-like array of poorly differentiated columnar/polygonal cells. Alpha-fetoprotein was demonstrated in some of the tumour cells using an immunoperoxidase technique. Alpha-fetoprotein secretion in this instance may have occurred because the gall bladder and the liver are of similar embryological origin. Alpha-fetoprotein may also be related to the resurgent expression of oncofetal antigens. This tumour may represent another rare cause of increased serum alpha-fetoprotein concentrations.

Aged↗
PubMed1995

Postirradiation colitis cystica profunda. Case report and literature review.

We report a rare case of rectosigmoid stricture associated with colitis cystica profunda that occurred 21 years after local therapeutic irradiation given for carcinoma of the bladder. We reviewed the literature and compared the clinical features, etiology, and macroscopic findings. The pathogenesis of the lesion may be related to repeated ulceration and regeneration, while chronic colonic ischemia may also play a role. The recognition of this rare entity is important because of its low-power "penetrating" architecture, which may be mistaken histologically as well-differentiated adenocarcinoma.

Aged↗