Increased aneusomy and long arm deletion of chromosomes 5 and 7 in the lymphocytes of Chinese workers exposed to benzene

Two of the most common cytogenetic changes in therapy- and chemical- related leukemia are the loss and long (q) arm deletion of chromosomes 5 and 7. The detection of these aberrations in lymphocytes of individuals exposed to potential leukemogens may serve as useful biomarkers of increased leukemia risk. We have used a novel fluorescence in situ hybridization (FISH) procedure to determine if specific aberrations in chromosomes 1, 5 and 7 occur at an elevated rate in the blood cells of workers exposed to benzene. Forty-three healthy workers exposed to a wide range of benzene concentrations (median 31 p.p.m., 8 h time-weighted average) and 44 unexposed controls from Shanghai were studied. Whole blood was cultured and metaphase spreads were harvested at 72 h. Benzene exposure was associated with increases in the rates of monosomy 5 and 7 but not monosomy 1 (P < 0.001, P < 0.0001 and P = 0.94, respectively) and with increases in trisomy and tetrasomy frequencies of all three chromosomes. Long arm deletion of chromosomes 5 and 7 was increased in a dose-dependent fashion (P = 0.014 and P < 0.0001) up to 3.5-fold in the exposed workers. These results demonstrate that leukemia-specific changes in chromosomes 5 and 7 can be detected by FISH in the peripheral blood of otherwise healthy benzene-exposed workers. We suggest that aberrations in chromosomes 5 and 7 may be useful biomarkers of early biological effect for benzene exposure.      

Role of anionic proteins in kidney stone formation: interaction between model anionic polypeptides and calcium oxalate crystals

PURPOSE: We tested the effect of molecular weight and amino acid composition (aspartate versus glutamate) in model peptides on calcium oxalate dihydrate (COD) formation to understand how known urinary inhibitor proteins might control spontaneous crystallization. MATERIALS AND METHODS: Supersaturated solutions of CaCl2 and Na2C2O4 in HEPES buffered saline solution were prepared at various calcium (Ca) to oxalate (Ox) ratios, but constant supersaturation, in the presence of protein inhibitors (polyaspartic acid molecular weight series or polyglutamic acid). The resulting crystals were collected and evaluated with optical microscopy. RESULTS: With no added inhibitors, the crystal size increased with Ca to Ox ratio, while the number of crystals decreased. With protein inhibitors at equivalent mass concentrations, intermediate molecular weight proteins produced a greater proportion of COD in Ca rich conditions than did either extreme. In Ox rich conditions, the proportion of COD was directly related to protein molecular weight. However, at equivalent molar concentrations, the proportion of COD produced was directly related to molecular weight under all conditions. Larger protein concentrations were required to produce COD at high Ox conditions, in proportion to the increased number of crystals produced. Polyglutamic acid had a much weaker effect on crystal structure, but it changed the COM morphology. CONCLUSIONS: The results suggest that a discrete number of protein molecules per crystal were required to direct crystallization toward COD, and that a characteristic size of polypeptide chain can be defined. The charge of the side group was not the sole determinant of this effect, as polyglutamic and polyaspartic acids behaved differently. Calcium oxalate crystal nucleation rates appeared to increase with Ox content.     

Cross‐sector emergency planning for water supply utilities and healthcare facilities

The purpose of this article is to outline the criticality of water supply in sustained operations of healthcare facilities, particularly during community emergencies, and to advocate for enhanced cross‐sector support from the water utilities in meeting this need. Information and ideas presented here were developed in the course of a regional project sponsored by the Metropolitan Washington Council of Governments (MWCOG) for development of emergency water supply operations plans for critical water uses in the Washington, DC, area.     

The First Reported Case of Anti-Dob Causing an Acute Hemolytic Transfusion Reaction

The antibodies of the Dombrock blood group system have only rarely been encountered in transfusion practice, and anti-Do^b has not previously been implicated in an acute hemolytic transfusion reaction. We have encountered the first such case involving a chronically transfused black female with hemoglobin SS disease and multiple antibodies in her serum. During a previous admission for sickle cell crisis, the patient received 3 units of compatible blood with no untoward effects. Serum obtained 21 days later contained, in addition to the known antibodies, anti-S plus an unidentified antibody showing characteristics of HTLA. Blood lacking the E, K1, Fy(a), Jk(b) and S antigens was obtained, and 2 least incompatible units were transfused. While administering the second unit, the patient complained of fever and low back pain, and hemoglobinemia was detected. Anti-Do^b was identified in the post-reaction samples by absorption-elution tests, and the patient was confirmed to be Do(a+b–). The first unit transfused during this hemolytic episode tested Do (b+). This case, and a similar case involving anti-Do^a reported in 1986, strengthens the belief that Dombrock antibodies are clinically significant and illustrates the need for their differentiation, prior to transfusion from less clinically significant HTLA antibodies.