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Biomedical subjects

K F Wong

Publications and source records attributed to K F Wong.

At least 19 recordsLinked to original sources
PubMed1992

Clonal evolution in primary 5q-syndrome.

Primary 5q-syndrome is a type of myelodysplastic syndrome characterized by refractory anemia, thrombocytosis, and hypolobulated megakaryocytes. The risk of leukemic transformation is low. A case of 5q- syndrome that occurred in a 42-year-old woman and was complicated by leukemic transformation 7 years after the initial diagnosis is reported. An additional clonal karyotypic anomaly, del(7q), was seen in the leukemic cells. The literature on leukemic and karyotypic evolution of primary 5q- syndrome is reviewed and the implication of karyotypic evolution is discussed.

Acute Disease↗
PubMed1992

Influence of phospholipid asymmetry on fusion between large unilamellar vesicles.

The ability of lipid asymmetry to regulate Ca(2+)-stimulated fusion between large unilamellar vesicles has been investigated. It is shown that for 100-nm-diameter LUVs composed of dioleoylphosphatidylcholine, dioleoylphosphatidylethanolamine, phosphatidylinositol, and dioleoylphosphatidic acid (DOPC/DOPE/PI/DOPA; 25:60:5:10) rapid and essentially complete fusion is observed by fluorescent resonance energy transfer techniques when Ca2+ (8 mM) is added. Alternatively, for LUVs with the same lipid composition but when DOPA was sequestered to the inner monolayer by incubation in the presence of a pH gradient (interior basic), little or no fusion is observed on addition of Ca2+. It is shown that the extent of Ca(2+)-induced fusion correlates with the amount of exterior DOPA. Further, it is shown that LUVs containing only 2.5 mol % DOPA, but where all the DOPA is in the outer monolayer, can be induced to fuse to the same extent and with the same rate as LUVs containing 5 mol % DOPA. These results strongly support a regulatory role for lipid asymmetry in membrane fusion and indicate that the fusogenic tendencies of lipid bilayers are largely determined by the properties of the monolayers proximate to the fusion interface.

Calcium↗
PubMed1992

Reactive hemophagocytic syndrome--a clinicopathologic study of 40 patients in an Oriental population.

PURPOSE: The purpose of this investigation was to assess the clinical spectrum and outcome of reactive hemophagocytic syndrome (RHS) in an Oriental population. PATIENTS AND METHODS: The investigation was a retrospective study of 40 consecutive patients with RHS diagnosed over a 4-year period in Queen Elizabeth Hospital, a community-based hospital in Hong Kong. RESULTS: The incidence of RHS in Hong Kong appeared to be comparable with that of Western countries. However, the spectrum of diseases associated with RHS was distinctly different. Forty percent of the cases were associated with malignant lymphoma. Another 40% of the cases were associated with infection, often due to bacteria, and infection due to the herpes group of viruses was uncommon, probably reflecting ethnic and geographic differences from the white population. Two patients had the acute lupus hemophagocytic syndrome, a distinctive form of RHS that occurs in patients with systemic lupus erythematosus. Treatment was basically supportive, with specific therapy also given for the underlying disease if present. Eighteen patients (45%) died of the acute disease, mostly as a result of complications of RHS or the underlying diseases. The development of disseminated intravascular coagulopathy was a poor prognostic factor. CONCLUSIONS: RHS is an uncommon disorder in Hong Kong and is often associated with malignant lymphoma or bacterial infection. A rigorous search for an underlying malignancy or infection is thus warranted once this diagnosis is made.

Adolescent↗
PubMed1992

CD56 (NKH1)-positive hematolymphoid malignancies: an aggressive neoplasm featuring frequent cutaneous/mucosal involvement, cytoplasmic azurophilic granules, and angiocentricity.

CD56 (NKH1) expression is a rare phenomenon in malignant lymphomas, mostly confined to those occurring in the nasal or nasopharyngeal region. In this study we provide a detailed clinicopathologic analysis of nine patients with CD56-positive hematolymphoid malignancies occurring in sites other than the upper aerodigestive tract. The disease occurred predominantly in young and middle-aged men (mean age, 40 years) who often presented with swinging fever, skin rash, and/or hepatosplenomegaly, usually in the absence of peripheral lymphadenopathy. There was frequent involvement of the skin and mucosal sites, such as the salivary gland, lungs, and small intestine. The disease pursued a highly aggressive course, with most patients dying within weeks despite cytotoxic therapy. Although the cytologic appearances and immunophenotypic profile varied from case to case, the group of tumors could be unified by two morphologic features, namely, the presence of azurophilic granules in the cytoplasm of the neoplastic cells and the frequent occurrence of angiocentric and angiodestructive infiltrates. Since CD56 reactivity appears to confer a poor prognosis in hematolymphoid malignancies, we recommended inclusion of CD56 antibody in the routine panel for immunophenotypic analysis.

Adult↗
PubMed1992

Multiple myeloma with tadpolelike cells and rosette formation.

A 65-year-old man with lower back pain was found to have multiple myeloma. Unique findings in the marrow aspirate smears of this patient were tadpolelike plasma cells and cellular rosettes simulating those seen in neuroblastoma. This case documents yet another facet of the broad morphologic spectrum of neoplastic plasma cells in multiple myeloma.

Aged↗
PubMed1992

Liver changes in reactive haemophagocytic syndrome.

Hepatomegaly and deranged liver functions are common findings in reactive haemophagocytic syndrome (RHS). We report the findings of 12 fatal cases of RHS in which histological materials of the liver are available for study. The underlying diseases of these patients included lymphoma/leukaemia (6 cases), disseminated undifferentiated carcinoma of the ovary (1 case), disseminated nasopharyngeal carcinoma complicated by tuberculosis (1 case), adenovirus pneumonia (1 case), pneumococcal pneumonia (1 case), typhoid fever (1 case), and possible drug intoxication (1 case). Ten patients had involvement of the liver by the underlying disease process which contributed to the marked hepatic derangement. Non-specific reactive hepatitis, sinusoidal dilatation and steatosis resulting from systemic or local effects of the associated diseases and the haemophagocytosis also added to the high incidence of liver abnormalities. A diffuse Kupffer cell hyperplasia with haemophagocytosis is characteristic of the syndrome, as all the cases showed increased numbers of bland-looking histiocytes within the hepatic sinusoids and haemophagocytosis which was moderate to marked in 8 cases and mild in 4. Thus the finding of Kupffer cell hyperplasia with prominent haemophagocytosis in liver biopsy is indicative of an element of RHS and warrants clinical monitoring. Differential diagnoses of haemophagocytosis in liver are also discussed.

Adolescent↗
PubMed1991

The acute lupus hemophagocytic syndrome.

OBJECTIVE: To characterize an unusual mode of presentation of systemic lupus erythematosus: acute and severe pancytopenia related to reactive hemophagocytosis. DESIGN: Retrospective case series. SETTING: Two general community hospitals in Hong Kong. PATIENTS: Six patients presenting with a reactive hemophagocytic syndrome, identified over a 3.5 year period, diagnosed with systemic lupus erythematosus according to the criteria of the American Rheumatism Association. RESULTS: In addition to severe pancytopenia and marrow hemophagocytosis, other characteristic features were fever, hypocomplementemia, high antinuclear antibody titer, and cutaneous and visceral vasculitis. There was no evidence of an underlying infection. The pancytopenia responded dramatically to treatment with steroids. CONCLUSION: Recognition of the acute lupus hemophagocytic syndrome and distinction from an infection-associated hemophagocytic syndrome is important because it responds well to steroid therapy. The evaluation of patients presenting with a hemophagocytic syndrome should include serologic tests for systemic lupus erythematosus.

Acute Disease↗
PubMed1991

Anaplastic large cell Ki-1 lymphoma involving bone marrow: marrow findings and association with reactive hemophagocytosis.

This report describes the bone marrow findings in four patients whose marrow was involved by anaplastic large-cell Ki-1 lymphoma, an uncommon event in this type of lymphoma. In the marrow aspirate smears, the involvement was subtle, and was in the form of isolated large cells with irregular nuclear configuration, coarse chromatin, prominent nucleoli, and basophilic cytoplasm which might be vacuolated. One case showed paradoxically massive involvement in the trephine biopsy taken from the same site as the marrow aspirate. Reactive histiocytic proliferation with hemophagocytosis was also present. Since marrow aspirate or biopsy may be the first pathologic specimen examined in patients having anaplastic large-cell Ki-1 lymphoma, it is important to be able to recognize the small population of neoplastic cells, which should lead to prompt treatment or further investigations as deemed necessary.

Adolescent↗
PubMed1991

Concurrent acute myeloid leukemia and systemic mastocytosis.

A 51-year-old woman presented with concurrent systemic mastocytosis and acute myeloid leukemia associated with a clonal karyotypic anomaly of t(8;21). Cytochemical, histologic, and cytogenetic studies helped in the distinction from a recently described entity: acute myeloid leukemia with marrow basophilia. Although the leukemia responded well to aggressive chemotherapy, the mastocytosis component worsened, illustrating the inherent resistance of mastocytosis to chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Are 'dysplastic' and hypogranular megakaryocytes specific markers for myelodysplastic syndrome?

Dysmegakaryocytopoiesis is an integral component of myelodysplastic syndrome (MDS), and has been shown in some studies to be an independent prognostic factor. Megakaryocytic hypogranulation, a feature we have noticed for some time to be fairly common in MDS and acute myeloid leukaemia (AML), has received little attention in the literature as a dysplastic feature of megakaryocytes. This study was performed to determine how frequently this feature was observed in MDS and the specificity of its occurrence. On review of archival materials, hypogranular megakaryocytes were observed in 80.3% of MDS, 30.6% of AML and 1.4% of controls. On the other hand, the other well-recognized dysmegakaryocytopoietic features (hypolobulation, multiple separate nuclei, micromegakaryocyte), though frequent in MDS or AML, were also observed in 20% of controls. We therefore propose including megakaryocytic hypogranulation as a cytological feature of myelodysplasia.

Acute Disease↗
PubMed1990

Protein-liposome conjugates with defined size distributions.

Conjugation of protein to liposomes by two coupling protocols is shown to result in vesicle aggregation. The degree of aggregation is directly related to the levels of protein conjugated to the liposomes. In an attempt to develop a method of generating stable, homogeneously sized protein-conjugated vesicles, highly aggregated liposome-protein conjugates were extruded through filters of defined pore size distributions, with no loss of protein binding. The extruded samples are relatively stable with respect to size and are easily prepared for various protein to lipid ratios. Liposome size has been shown to be a major factor in determining the in vivo blood circulation times of liposomes. A corresponding, significant enhancement in the blood circulation lifetimes for extruded versus aggregated streptavidin-liposome conjugates is observed. Furthermore, the stability of streptavidin-liposome conjugates in vivo was shown by the binding of biotin to liposomes isolated from plasma 1 and 4 h post-injection. In conclusion, extrusion of the aggregated systems obtained on coupling proteins to liposomes provides a convenient and general method for generating homogeneously sized protein-liposome conjugates.

Animals↗