Theodore Zwerdling

Nondestructive Identification of Individual Leukemia Cells by Laser Trapping Raman Spectroscopy

Currently, a combination of technologies is typically required to assess the malignancy of cancer cells. These methods often lack the specificity and sensitivity necessary for early, accurate diagnosis. Here we demonstrate using clinical samples the application of laser trapping Raman spectroscopy as a novel approach that provides intrinsic biochemical markers for the noninvasive detection of individual cancer cells. The Raman spectra of live, hematopoietic cells provide reliable molecular fingerprints that reflect their biochemical composition and biology. Populations of normal T and B lymphocytes from four healthy individuals and cells from three leukemia patients were analyzed, and multiple intrinsic Raman markers associated with DNA and protein vibrational modes have been identified that exhibit excellent discriminating power for cancer cell identification. A combination of two multivariate statistical methods, principal component analysis (PCA) and linear discriminant analysis (LDA), was used to confirm the significance of these markers for identifying cancer cells and classifying the data. The results indicate that, on average, 95% of the normal cells and 90% of the patient cells were accurately classified into their respective cell types. We also provide evidence that these markers are unique to cancer cells and not purely a function of differences in their cellular activation.

COMPARISON OF REAL-TIME MICROVASCULAR ABNORMALITIES IN PEDIATRIC AND ADULT SICKLE CELL ANEMIA PATIENTS

The conjunctival microcirculation in 14 pediatric and eight adult sickle cell anemia (SCA) patients was studied using computer‐assisted intravital microscopy. The bulbar conjunctiva in SCA patients in both age groups exhibited a blanched/avascular appearance characterized by decreased vascularity. SCA patients from both age groups had many of the same abnormal morphometric [vessel diameter, vessel distribution, morphometry (shape), tortuosity, arteriole:venule (A:V) ratio, and hemosiderin deposits] and dynamic [vessel sludging/sludged flow, boxcar blood (trickled) flow, and abnormal flow velocity] abnormalities. A severity index (SI) was computed to quantify the degree of vasculopathy for comparison between groups. The severity of vasculopathy differed significantly between the pediatric and adult patients (SI: 4.2 ± 1.8 vs. 6.6 ± 2.4; P = 0.028), indicative of a lesser degree of overall severity in the pediatric patients. Specific abnormalities that were less prominent in the pediatric patients included abnormal vessel morphometry and tortuosity. Sludged flow, abnormal vessel distribution, abnormal A:V ratio, and boxcar flow appeared in high prevalence in both age groups. The results indicate that SCA microvascular abnormalities develop in childhood and the severity of vasculopathy likely progresses with age. Intervention and effective treatment/management modalities should target pediatric patients to ameliorate, slow down, or prevent progressive microvascular deterioration. Am. J. Hematol., 2010.

Monosomy 21q22.11‐q22.13 presenting as a Fanconi anemia phenotype

We report on a 5‐year‐old Caucasian female with multiple anomalies whose deletion, 46,XX,del(21)(q22.11q22.13), was determined by a 105K oligonucleotide‐based microarray. This case is a unique deletion that mimicked Fanconi anemia (combination of thrombocytopenia, thumb anomalies, congenital heart defects, borderline small head circumference, strabismus, hydronephrosis, and significant developmental delay) but testing for Fanconi anemia was negative, as was testing for a wide array of genetic/metabolic conditions. Microarray testing done at 5 months failed to demonstrate the interstitial deletion that was found on a newer generation microarray test performed after 3 years of age. When compared to other reported cases of partial monosomy 21q, the unique features of this case include: (1) cleft palate, although high palate is reported in other cases; (2) neonatal thrombocytopenia requiring platelet transfusion; (3) a platelet function defect, reported previously as platelet storage pool defect as part of a familial platelet disorder; and (4) an immune function defect. Similar to other reported patients with terminal 21q deletion, this child had significant developmental delay, and feeding and growth problems. This case also highlights the ability for newer technology microarrays to identify small interstitial deletions previously missed by an earlier version microarray. The advances in the microarray technologies are allowing us to better define new phenotypes and leading to the identification of a diagnosis for many patients who have been previously undiagnosed. Review of the genes involved in these novel deletions allows the caring physician to design surveillance strategies that are custom‐designed for these unique patients.

Anti‐tumor activity of the HSP90 inhibitor SNX‐2112 in pediatric cancer cell lines

HSP90 plays a central role in stabilizing client proteins involved in malignant processes. SNX‐2112 is an orally administered potent HSP90 inhibitor that has demonstrated pre‐clinical anti‐tumor activity in adult malignancies. As many childhood tumors depend upon HSP90 client proteins, we sought to test the pre‐clinical efficacy of SNX‐2112 in a panel of pediatric cancer cell lines both as a single‐agent and in combination with cisplatin (CP).

EXCHANGE TRANSFUSION THERAPY AND ITS EFFECTS ON REAL-TIME MICROCIRCULATION IN PEDIATRIC SICKLE CELL ANEMIA PATIENTS: AN INTRAVITAL MICROSCOPY STUDY

Periodic blood exchange transfusion is a treatment modality commonly used to manage pediatric sickle cell anemia at the University of California Davis Medical Center. The goal of exchange transfusion therapy is to ameliorate vasoocclusion and improve tissue perfusion by removing sickled red blood cells and introducing normal red blood cells. Using computer-assisted intravital microscopy, pretransfusion and posttransfusion microvascular characteristics were analyzed. In this study, the bulbar conjunctiva exhibited a “blanched” avascular appearance in all 6 pediatric sickle cell anemia patients before transfusion, indicative of tissue hypoperfusion and ischemia. Immediately after transfusion, substantial improvement in vascularization and tissue perfusion resulted, reflected by the enhanced appearance of capillaries and arterioles. In addition, a decrease in red cell velocity was observed. These observations provide evidence that exchange transfusion therapy is beneficial in ameliorating vasoocclusion and improving tissue perfusion. However, with the paradoxical posttransfusion decrease in red cell velocity presumably due to induced hyperviscosity from the large transfusion volume, blood flow is still impaired. This decreased velocity may thwart efforts to improve oxygen delivery through transfusion and may, to some extent, promote vasoocclusion instead. This paradoxical result warrants further investigation on the effects of transfusion volume and viscosity in the exchange transfusion process.

Floating–Harbor syndrome and intramedullary spinal cord ganglioglioma: Case report and observations from the literature†

We report on a 5‐year‐old male with expressive language delay, developmental delay, short stature, and facial anomalies consistent with Floating–Harbor syndrome (FHS). In addition, he developed an intramedullary ganglioglioma. This is the first reported case of a tumor associated with FHS, and may represent an as yet undefined genetic link between spinal cord tumors and FHS, adding this syndrome to the growing list of disorders with a predisposition for tumor development.