[Clinical features and molecular diagnosis of three patients with DiGeorge anomaly].

OBJECTIVE: To investigate the clinical features and molecular diagnostic methods of three patients with DiGeorge anomaly. METHOD: The clinical manifestations and immunological features of the three cases with DiGeorge anomaly were analyzed. We detected the chromosome 22q11.2 gene deletion by fluorescence in situ hybridization (FISH). RESULT: (1) CLINICAL MANIFESTATIONS: All three cases had varying degrees of infection, congenital heart disease and small thymus by imaging; two cases had significant hypocalcemia (1.11 mmol/L and 1.22 mmol/L, respectively), accompanied by convulsions; only 1 case had cleft palate and all had no significant facial deformity. (2) Immunological characteristics: All three cases had varying degrees of T-cell immune function defects (percentage of T lymphocytes was 24% - 43%, absolute count was 309 - 803/µl), and levels of immunoglobulin G, A, M, and percent of B lymphocytes and absolute count were normal. (3) Detection of the chromosome 22q11.2 gene deletion: 400 cells of each case were detected. All cells showed two green and one red hybridization signal, indicating the presence of gene deletions in chromosome 22q11.2. (4) OUTCOME: All three cases were treated with thymosin, and appropriate clinical intervention for cardiac malformations, hypocalcemia, and were followed-up for 4 - 18 months, the prognosis was good. CONCLUSION: DiGeorge anomaly showed diverse clinical manifestations. We should consider the disease if patients had congenital heart disease, thymic hypoplasia, hypocalcemia and/or impaired immune function. FISH for detecting chromosome 22q11.2 gene deletion can be used as accurate and rapid diagnostic method. Thymosin treatment and other clinical intervention may help to improve the prognosis of patients with partial DiGeorge anomaly.

Percutaneous absorption of arsenic from environmental media.

Current knowledge of percutaneous absorption of arsenic is based on studies of rhesus monkeys using soluble arsenic in aqueous solution, and soluble arsenic mixed with soil (Wester et al., 1993). These studies produced mean dermal absorption rates in the range of 2.0-6.4% of the applied dose. Subsequently, questions arose as to whether these results represent arsenic absorption from environmental media. Factors such as chemical interactions, the presence of other metals, and the effects of weathering on environmental media all can affect the nature of arsenic and its potential for percutaneous absorption. Therefore, research specific to more relevant matrices is important. The focus of this effort is to outline study design considerations, including particle size, application rates, means of ensuring skin contact and appropriate statistical evaluation of the data. Appropriate reference groups are also important. The potential for background exposure to arsenic in the diet possibly obscuring a signal from a dermally applied dose of arsenic will also be addressed. We conclude that there are likely to be many site- or sample-specific factors that will control the absorption of arsenic, and matrix-specific analyses may be required to understand the degree of percutaneous absorption.