Treatment of cutaneous angiosarcoma of the scalp and face in Chinese patients: local experience at a regional hospital in Hong Kong.

INTRODUCTION: Angiosarcoma is a rare aggressive sarcoma that occurs mostly in the skin of the head and neck in the elderly population. The optimal management is dubious and most studies are from Caucasian populations. We aimed to examine the treatment and outcome of this disease in Chinese patients. METHODS: Data of patients with histopathologically verified cutaneous angiosarcoma of the head and neck during December 1997 to September 2016 were retrieved from our hospital cancer registry. The demographic data, clinicopathological information, modality of treatment, and outcomes were reviewed. RESULTS: During the study period, 17 Chinese patients were treated. Their median age was 81 years. The tumours were present in the scalp only (n=11), face only (n=4), or both scalp and face (n=2). Only two patients had distant metastases. The modalities of treatment were surgery (n=6), surgery and adjuvant radiotherapy (n=1), palliative radiotherapy (n=5), or palliative chemotherapy (n=3). The remaining two patients refused any treatment initially. Of the seven patients treated surgically, there were four local and two regional recurrences. The median time to relapse was 7.5 months. Overall, 16 patients had died; causes of death were disease-related in 12 whereas four other patients died of inter-current illnesses. One patient was still living with the disease. The median overall survival was 11.1 months and the longest overall survival was 42 months. CONCLUSION: The outcome of angiosarcoma in our series is poor. A high index of suspicion is mandatory for prompt diagnosis. Adjuvant radiotherapy is recommended following surgery. The benefit and role of systemic treatment in various combinations with surgery or radiotherapy require further study.

A cluster of chilblains in Hong Kong.

OBJECTIVE: To report a recent clustering of chilblain cases in Hong Kong. DESIGN: Case series. SETTING: A regional hospital and a social hygiene clinic in the New Territories West, Hong Kong. PATIENTS: Patients with a clinical diagnosis of chilblains in February 2008. RESULTS: Eleven patients with chilblains were identified; seven (64%) gave an antecedent history of prolonged exposure to cold. They all presented with erythematous or dusky erythematous skin lesions affecting the distal extremities, especially fingers and toes. Laboratory tests revealed elevated antinuclear antibodies titres in two, positive rheumatoid factor in two, presence of cold agglutinins in one, and a raised anti-DNA titre (>300 IU/mL) in one. Skin biopsies were performed in six patients, four of them showed typical histopathological features of chilblains. In the patient with systemic lupus erythematosus, features of vasculitis were suspected, and in the one with pre-existing juvenile rheumatoid arthritis, there were features of livedo vasculitis. In 10 (91%) of the patients, the skin lesions had resolved when they were last assessed (at the end of March 2008), but had persisted in the patient who had pre-existing systemic lupus erythematosus. CONCLUSION: The recent clustering of chilblains was possibly related temporally to the prolonged cold weather at the end of January to mid-February. In our series, most of the patients developed chilblains as an isolated condition and resolved spontaneously within a few weeks. Laboratory tests and skin biopsies for chilblains are not necessary, unless the condition persists, the diagnosis in doubt or an underlying systemic disease is suspected.

The characteristics of near prism induced fixation disparity curve in Hong Kong Chinese.

The characteristics of prism induced fixation disparity curve at near were studied in 56 asymptomatic young adult Hong Kong Chinese (average age 21 years). The percentage distribution of types of fixation disparity curves was found to be similar to some previous studies, with a higher prevalence of Type I curve (64.3%), followed by Type II (28.6%) and Type III (7.1%) curves. No Type IV curve was revealed from the sample. Two modified measurement approaches were applied to study the effect of measurement techniques on the parameters of fixation disparity curve obtained. A thorough description of the techniques was given. Although a significant difference in the x- and y-intercepts was obtained between different methods, the curve type and slope were not affected. The average y-intercepts (fixation disparity) were 2.72 min of arc and 3.54 min of arc from two methods respectively. Forty-one subjects had x-intercept (associated phoria) found from the curve. The average values were 2.42 delta base-out and 3.54 delta base-out from two methods respectively.

Optimization of the parallelogrammic grating diffraction efficiency for normally incident waves.

The diffraction directivity of parallelogrammic gratings with second-order pitch is examined for a plane wave normally incident upon a corrugated waveguide structure. The three diffracted components are assumed to be in the form of guided waves, which permits a self-consistent calculation. The efficiencies of diffraction into the horizontal components are obtained. Also, the dependence of efficiency on grating thickness, waveguide thickness, grating pitch, and angle of inclination is determined. The approach provides a useful simulation tool for optimizing the design parameters for waveguide couplers with an orthogonal source.

Complementary mutations in an antigenic peptide allow for crossreactivity of autoreactive T-cell clones.

T cells recognize antigen by formation of a trimolecular complex in which the T-cell receptor (TCR) recognizes a specific peptide antigen within the groove of a major histocompatibility complex (MHC) molecule. It has generally been assumed that T-cell recognition of two distinct MHC-antigen complexes is due to similarities in the three-dimensional structure of the complexes. Here we report results of experiments examining the crossreactivity of TCRs recognizing the myelin basic protein peptide MBPp85-99 and several of its analogs in the context of MHC. We demonstrate that single conservative amino acid substitutions of the antigenic peptide at the predominant TCR contact residues at positions 91 and 93 totally abrogate reactivity of specific T-cell clones. Yet, when a conservative substitution is made at position 91 concomitant with a substitution at position 93, the T-cell clones regain reactivity equivalent with that of the original stimulating peptide. Thus, the exact nature of the amino acid side chains engaging one TCR functional pocket may change the apparent selectivity of the other predominant TCR functional pocket, thus suggesting a remarkable degree of receptor plasticity. This ability of the TCR-MHC-peptide complex to undergo conformational changes provides a conceptual framework for reconciling the apparent paradox of the extreme selectivity of the TCR and its remarkable crossreactivity with different MHC-peptide complexes.