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Biomedical subjects

H L Chan

Publications and source records attributed to H L Chan.

At least 91 records · Page 5Linked to original sources
PubMed1994

Sweet's syndrome: clinicopathologic study of eleven cases.

BACKGROUND: The clinicopathologic manifestations of Sweet's syndrome associated with malignancy have been rarely studied in a large series. METHODS: We describe the clinical features of Sweet's syndrome in 11 patients seen during the past 12 years. Histopathologic findings of these patients are discussed. The clinicopathologic manifestations of 249 cases of Sweet's syndrome reported in the literature were reviewed. RESULTS: The clinicopathologic manifestations of Sweet's syndrome associated with hematologic disorders (HSS) were more severe and characterized by bullous pyoderma with more pronounced epidermal changes and ulceration, anemia, giant platelets and abnormal platelet counts. Approximately 40% of the Sweet's syndrome reported in the literature were associated with hematologic malignancy, and the other 7% of patients had solid tumors. CONCLUSIONS: Sweet's syndrome can be classified into three types: (1) association with hematologic disorders (HSS); (2) association with solid tumors (SSS); and (3) idiopathic or associated with various other disorders (ISS).

Adenocarcinoma, Follicular↗
PubMed1994

'Pregnancy tumour' of the nasal septum.

The origins of pyogenic granulomas are subject to much debate. It is viewed as overexuberant growth of epithelium and capillary loops (i.e. granulation tissue) in response to trauma by some authorities, and is considered a capillary haemangioma with a unique lobular organization by others. Although the pathogenesis of the lesion is unclear, marked variation in sexual distribution suggests a hormonal factor, and the profound metabolic and endocrine changes in pregnancy seem to provide especially fertile soil for its growth. Its appearance and rapid rate of growth might easily lead the practitioner to mistake its identity for something more ominous.

Adult↗
PubMed1994

Immunohistochemical analysis of dermal mononuclear cell infiltrates in cutaneous lupus erythematosus, polymorphous light eruption, lymphocytic infiltration of Jessner, and cutaneous lymphoid hyperplasia: a comparative differential study.

Cutaneous lupus erythematosus (LE), polymorphous light-eruption (PMLE), lymphocytic infiltration of Jessner (LIJ), and cutaneous lymphoid hyperplasia (CLH) are often difficult to differentiate from one another by light microscopic examination. We conducted an immunohistochemical analysis of the mononuclear cell infiltrates in 13 LE, 12 PMLE, 10 LIJ, and 13 CLH with various antibodies. Antibodies L26, UCHL1, and S100 achieved statistically significant differences among the four diseases, but because of the overlaps in the number of UCHL1(+) T cells and S100 protein (+) cells in individual cases, these two antibodies were not useful. Only CLH could be distinguished from LE, PMLE, and LIJ by a greater number of CD20(+) B cells. The latter three conditions could not be differentiated. Contrary to previous reports, plasmacytoid-monocytes were not found to be increased in LIJ for the differentiation of the latter from LE and PMLE. Our results support the conclusion that CLH is a reactive lymphoid hyperplastic process with proliferation of both B and T cells, whereas the T cell was the predominant cell type in the infiltrates of LE, PMLE, and LIJ, indicating that they were related to T cell disorders. The histiocyte was only a minor component cell. The plasmacytoid monocyte in general was not significantly present in all four conditions, but relatively more plasmacytoid monocytes were present in CLH.

Analysis of Variance↗
PubMed1994

Dermal mast cell density and pruritus in end-stage renal failure.

Skin mast cell density was determined in two age- and sex-matched groups of patients with end-stage renal failure, one with severe uraemic pruritus (n = 9) and the other without (n = 9). In each group, seven patients were on chronic haemodialysis. In uraemic patients without pruritus, skin mast cell density was similar to that in eight healthy controls (40.1 +/- 10.2 mm2 versus 46.5 +/- 20.6 mm2; P = 0.44), a result also obtained when only the patients on haemodialysis were considered (39.3 +/- 14.7 versus 46.5 +/- 20.6; P = 0.46), showing that haemodialysis per se did not cause mast cell proliferation. In contrast, uraemic patients with itch had significantly higher dermal mast cell counts when compared with those without itch (71.8 +/- 36.4 mm2 versus 40.1 +/- 12.9 mm2; P = 0.01). However, there was no difference in serum parathyroid hormone (PTH) and calcium or phosphate concentrations between the two groups. In addition, there was no significant correlation between dermal mast cell density and serum PTH, calcium or phosphate concentrations. These data suggest that uraemic pruritus may be related to mast cell proliferation in the skin.

Adult↗
PubMed1994

Polymyositis associated with symptomless nasopharyngeal carcinoma.

We describe a 42-year-old Chinese patient with polymyositis and nasopharyngeal carcinoma. The polymyositis was complicated by respiratory failure needing mechanical ventilation despite conventional therapy. Treatment of the carcinoma was associated with recovery of muscle strength. To our knowledge this is the first reported association of polymyositis with nasopharyngeal carcinoma.

Adult↗
PubMed1993

Sequence, transcriptional mapping, and overexpression of p47, a baculovirus gene regulating late gene expression.

A 2.8-kb region of the Autographa californica nuclear polyhedrosis virus genome was sequenced and found to contain an open reading frame (p47) which was capable of rescuing a previously characterized temperature-sensitive mutant, ts317 (S. Partington, H. Yu, A. Lu, and E. B. Carstens, Virology 157:91-102, 1990). Transcriptional mapping demonstrated that an early 4.2-kb RNA encoded the p47 open reading frame and probably overlapped the 39K delayed-early gene. The p47 open reading frame was cloned behind the polyhedrin promoter in a baculovirus transfer plasmid, which was then used to prepare a recombinant baculovirus overexpressing the p47 polypeptide. The overexpressed polypeptide was used to prepare p47-specific monoclonal antibodies. These antibodies detected a polypeptide of 47 kDa in A. californica nuclear polyhedrosis virus-infected cells, demonstrating that p47 is expressed as an authentic viral product. The p47 gene product was localized to the nucleus of infected cells, supporting the hypothesis that it is involved in regulating viral transcription at late times postinfection.

Amino Acid Sequence↗
PubMed1992

Fixed drug eruptions due to co-trimoxazole.

Co-trimoxazole is a less common cause of fixed drug eruption (FDE). The offending drug is usually sulfamethoxazole but reactions to trimethoprim have been reported. Fixed drug eruption is uncommon in children compared to adults as the drugs most commonly responsible are seldom or never used in children. We report four patients with FDE to co-trimoxazole, three of whom were children. All were given the offending drug for upper respiratory tract infections. Each of the patients had several episodes of FDE before the diagnosis was suspected. The patients, as well as the general practitioners, initially thought that the skin lesions were related to the infections rather than the drugs. One of the patients had FDE to trimethoprim and the intensity of his reaction appeared to be dose-related. As co-trimoxazole is being used more commonly, we would expect to see more FDE, even among the paediatric age group.

Adolescent↗
PubMed1992

A scanning and transmission electron microscopic study of the membranes of chicken egg.

Questions regarding the structure of the inner and outer shell membranes of the chicken egg were addressed in this study by correlating observations from light microscopy and scanning and transmission electron microscopy. The egg membrane had a limiting membrane, which measured .9 to .15 microns in thickness and appeared to be a continuous and an impervious layer, but the shell membrane did not. Under the SEM, each membrane was seen to be made up of several fibre layers. In the tear preparations viewed under the SEM two layers were observed in the egg membranes and three to five layers in the shell membrane, with an apparent plane of cleavage between each layer. Each fibre was made up of a central core and an outer mantle layers. The central core was perforated by channels which measured .08 to 1.11 microns in diameter and ran longitudinally along the length of the fibre. Between the mantle layer and the fibre core was a gap or cleft measuring between .03 to .07 microns. The diameter of the fibres of the inner layer of the egg membrane ranged between .08 to .64 microns, whereas those of the outer layer of the same membrane ranged from .05 to 1.11 microns. Fibres in the shell membrane ranged from .11 to 4.14 microns diameter.

Animals↗
PubMed1992

The toxic strept syndrome: two case reports.

We describe two patients with group A beta hemolytic streptococcal septicemia from minor foci in the skin. They developed extreme toxemia, mental obtundation and multi-system organ failure associated with diffuse erythema. They both survived after appropriate antibiotic and intense supportive therapy. These are examples of the "toxic strept syndrome" which is similar to staphylococcal toxic shock.

Anti-Bacterial Agents↗
PubMed1991

Atrophie blanche. A clinicopathological study of 27 patients.

Twenty seven patients (8 males and 19 females) with atrophie blanche were observed in the past 7-years. The mean age at onset was 32 years (ranging from 23 years to 57 years) and 19 years (ranging from 11 years to 36 years) for male and female patient, respectively. The mean disease duration was 2.5 years (ranging from 2 months to 16 years) prior to their consultation. Sixty-three percent of them had summer exacerbation. Four patients had essential cryoglobulinemia, one of whom also developed bilateral iliofemoral artery stenosis one year later. Twelve patients also manifested concurrent purpura pigmentosa chronica (PPC)-like lesions. The observation of the natural course and clinical morphology, being divided into white atrophy-predominant and ulcer-predominant type, led to the impression that atrophie blanche and livedo vasculitis are synonyms with the same disease spectrum. Furthermore, white atrophy is not ulcer scars but lesions de novo suggesting dermal vasculopathy. An attempt was made to explain the uniqueness of clinical morphology. First line treatment included local wound care, bed rest and low-dose aspirin plus dipyridamole. Thirteen patients responded to these treatment either at the first attack or the recurrent episodes. Heparin (5000 units subcutaneous injection once daily) was effective for control of intractable painful ulceration in active stage in 70% of the remaining patients.

Adolescent↗
PubMed1991

[Evaluation of molluscicidal effect of nicotinanilide against Oncomelania snails].

Both nicotinanilide hydrochloride and nicotinanilide sulfate are water-soluble, their IC50 and LC90 against Oncomelania snails being around 0.3 mg/L and 0.5 mg/L, respectively, during 24 hour exposure at 25 degrees C followed by a 7-day recovery period. The laboratory tests and field trials showed that over 90% of snails were killed within 3 days exposure at 1-2 mg/L, and that 18.4%-100% snails on moist soil were killed at over 20 degrees C, exposed to spraying dosage of 1-2 g/m2 for 1-3 days. The chemical is highly effective against snails eggs at early stage (cell stage). The LC50 of nicotinanilide to Aristichthys nobilis and Pseudorasbora parva is about 200 mg/L. The acute oral LD50 in mice is about 2 g/kg. Plants tolerate the chemical at 1-2 g/m2, but some leaves wilted at greater than or equal to 5 g/m2, dicotyledon in particular. Dermatitis has been reported in individuals frequently exposing to nicotinanilide wettable powder during massive spraying.

Animals↗