Microfabricated high-throughput electronic particle detector.

We describe the design, fabrication, and use of a radio frequency reflectometer integrated with a microfluidic system, applied to the very high-throughput measurement of micron-scale particles, passing in a microfluidic channel through the sensor region. The device operates as a microfabricated Coulter counter [U.S. Patent No. 2656508 (1953)], similar to a design we have described previously, but here with significantly improved electrode geometry as well as including electronic tuning of the reflectometer; the two improvements yielding an improvement by more than a factor of 10 in the signal to noise and in the diametric discrimination of single particles. We demonstrate the high-throughput discrimination of polystyrene beads with diameters in the 4-10 microm range, achieving diametric resolutions comparable to the intrinsic spread of diameters in the bead distribution, at rates in excess of 15 x 10(6) beads/h.

Diffusion-based electron thermometry using a three-junction single-electron transistor.

We describe a new mK-range nanoscale thermometer, based on a unique three-junction radio frequency single-electron transistor. The three-junction geometry allows separation of the thermal and electronic pathways, providing a potentially significant reduction of measurement-induced Joule heating. A radio frequency embedding tank circuit allows very fast readout. We demonstrate electronic and thermal operation, supported by numerical simulations. Applications to minimal back-action calorimetry and bolometry are discussed.

A feasible approach to all-electronic digital labeling and readout for cell identification.

We present two critical innovations that enable a unique, purely electronic approach to microfluidic whole-cell analysis, focusing on the problem of cell identification and sorting. We used fully-scalable lithographic techniques to microfabricate digital barcodes, providing a means for low-cost, large volume production. We have demonstrated molecular functionalization of the barcodes, using biotin-streptavidin, as well as human CD4 antibody, and we have successfully linked the barcodes to polystyrene beads using the biotin-streptavidin complex. This functionalization allows unique barcodes to be attached to specific cell types, based on phenotype. We have also implemented an electronic barcode readout scheme, using a radio frequency microsensor integrated in an elastomeric microfluidic channel, that can read individual barcodes at rates in excess of 1000 labels s(-1). The barcodes are biologically compatible, and coupled with the electronic sensing technology, provide a route to compact, inexpensive, disposable cell identification, sorting and purification.

Gold nanoparticle decoration of DNA on silicon.

Electrostatic assembly of cationic nanoparticles onto the negatively charged backbone of double-stranded DNA has been shown to produce one-dimensional chains with potential use as nanoelectronic components. In this paper, micron long DNA templates stretched on aminosilane- and hexamethyldisilazane-modified silicon surfaces are used to assemble 3.5 nm gold nanoparticles passivated with cationic thiocholine. Atomic force microscopy is used to analyze the density and defects along the approximately 5 nm high structures, with comparison between positively charged and neutral surfaces. Low background adsorption of nanoparticles is facilitated by both these surface chemistries, while the neutral surface yields a more densely packed assembly.

Teaching multiplication facts to students with learning disabilities.

Multiple baseline designs were used to examine the effects of an instructional package on accuracy of performance in solving multiplication facts by 3 students with learning disabilities. The instructional package included the following components: (a) a modified instructional sequence in which multiplication facts were grouped into the zeros, ones, doubles, fives, and nines categories, and those remaining; (b) identification of the category in which each fact belonged; (c) mnemonic strategies associated with solving facts in each category; and (d) steps to be completed for solving facts in each category. Results indicated that the instructional package produced substantial and immediate effects. After receiving instruction, a participant's accuracy was often 100%, and this was maintained throughout the evaluation even as other strategies were introduced. Comparable results occurred across students, demonstrating replication of the effects of the instructional package.

Tc-99m sestamibi uptake in infiltrating ductal carcinoma of the breast in a male patient.

A 73-year-old man had an asymptomatic, slowly growing breast nodule. The mammographic appearance was highly suspicious of a malignancy, but the patient refused to undergo a biopsy. Because breast carcinoma has been previously described to accumulate Tc-99m MIBI in women, mammoscintigraphy was performed as a complementary examination. Uptake of the agent was noted.

Results of treatment of stage I-III breast cancer in black Americans. The Cook County Hospital experience, 1973-1987.

Whether the prognosis for black women with breast cancer differs from that of nonblack women remains controversial. The treatment results of 526 black women who received definitive therapy for Stage I-III breast cancer at Cook County Hospital, 1973 through 1987 are presented. The 5-year and 10-year projected survival rates for 272 node-negative patients (83.9% and 76.6%, respectively) and for 72 node-positive nonadjuvant treated patients (58.1% and 35.2%, respectively) are similar to those reported in the literature for nonblack patients. Adjuvant therapy improved the projected relapse-free (P = 0.0744) and overall survival curves (P = 0.0448) for 182 node-positive patients compared with nonadjuvant patients. The greatest benefit was seen for patients greater than 50 years of age with one to three positive nodes. The incidence of estrogen and progesterone receptors was found to be similar to those reported for nonblack patients. Once breast cancer has been diagnosed and appropriately treated, there appear to be few differences in the natural history of breast cancer between black and nonblack patients.

Effects of phorbol esters on endothelial cell microfilaments: laser scanning confocal microscopy and quantitative morphometry of dose dependent changes.

Phorbol esters are known to alter microfilaments but it is not clear if the changes correspond to modulation of the phosphoinositide turnover/protein kinase C system. The novel technique of laser scanning confocal epifluorescence was used to study fiber orientation in phorbol ester treated cells. We treated endothelial cells with control agents and agents known to stimulate protein kinase C: 4 alpha-phorbol, phorbol 12-myristate 13-acetate (PMA), phorbol dibutyrate (PDB), or lipopolysaccharide. After incubation with the test agents, the endothelial cell microfilaments were stained with rhodamine pholloidin and viewed by conventional epifluorescence and by laser scanning confocal epifluorescence microscopy. The images obtained by the confocal microscopy corresponded to a thin optical section through the cells, 300 nm or more in thickness. The microfilaments extended predominantly in the plane of focus. After exposure of the cells to phorbol esters, the stress fibers became more nearly parallel in arrangement or were shortened, but remained in the plane of focus. The modification of microfilaments in response to phorbol esters was quantitated by a single blind analysis. In order to compare the morphological changes with a biochemical action of the phorbol esters, we measured phosphoinositide turnover. The dose-dependence of morphological changes was compared and contrasted to the dose-dependent effect of phorbol esters on bradykinin-stimulated phosphoinositide turnover. PMA had about the same EC50 (1-5 nM) for both biochemical and morphological processes. PDB was less potent in inducing the disruption of microfilament structure than in inhibiting phosphoinositide turnover. Lipopolysaccharide was ineffective in inducing a morphological change under these conditions. A simple activation of protein kinase C is insufficient to explain the dose-dependent effects of phorbol esters. Thus a morphometric analysis can help distinguish the potency of cytoskeleton modulators.

Cutaneous thick melanoma. Prognosis and treatment.

Among proponents of elective lymph node dissection (ELND) for clinical stage I melanoma, controversy exists as to whether there is an upper limit of tumor thickness beyond which ELND should not be considered. We reviewed 169 patients with clinical stage I and II melanoma that was greater than or equal to 3.0 mm thick and who were treated at the University of Illinois Hospital, Chicago. Of 139 patients with clinical stage I disease, 117 underwent ELND. Five- and ten-year survival rates were 55.7% and 48.9%, respectively. Multifactorial analysis demonstrated that anatomical location, level, pathologic stage, and ulceration were the best predictors of survival. Thickness did not emerge as a significant variable. Our findings do not support basing treatment decisions, eg, ELND in this group of patients, solely on the thickness of the primary tumor. We continue to recommend ELND in patients with either intermediate or thick melanomas.

Soft tissue sarcomas of the adult thoracic wall.

Forty-nine adult patients with soft tissue sarcomas of the thoracic wall have been treated by the Division of Surgical Oncology at the University of Illinois. Fibrosarcoma was the most common histologic type (20%). Patients with dermatofibrosarcoma protuberans had the longest mean overall survival time (150.8 months). The mean overall survival time for all patients was 98.2 months, and the disease-free 2-, 5-, and 10-year survival rates were 68%, 51%, and 34%, respectively. Wide excision was the treatment of choice; selected patients also received adjuvant radiotherapy, chemotherapy, or both. In all 10-year survivors, the sarcomas were low grade and well differentiated, or were less than or equal to 5.0 cm in diameter. Aggressive treatment afforded these patients good long-term results.

Soft tissue sarcomas of the distal extremities.

Multimodality therapy and limb salvage procedures constitute a significant advance in the treatment of soft tissue sarcoma of the extremity. The applicability of these procedures to soft tissue sarcoma of the distal extremities was evaluated in a retrospective study of 159 such cases treated during a 10-year period. Thirty-seven patients were treated by operation alone, 57 had operation and adjuvant chemotherapy, and 65 had multimodal therapy. The distal extremities are unusual sites for soft tissue sarcomas and accounted for only 20% of our patients with sarcoma. The majority of patients were younger than 50 years and the sex distribution was approximately equal. The major histologic types were synovial cell sarcoma (18.2%), fibrosarcoma (15%), liposarcoma (13.8%), and rhabdomyosarcoma (13.8%). The 5-year survival rate was 72% with multimodality therapy, 72% for operation and chemotherapy, and 51% for operation alone. The local recurrence rate was 13% with operation alone, 9% with operation and adjuvant chemotherapy, and 12% with multimodality therapy. Based on our review, wide local excision and adjuvant chemotherapy proved to be as effective as multimodal therapy.

Pelvic exenteration.

Sixty-eight patients at the University of Illinois, Cook County, and the West Side Veterans Administration hospitals underwent pelvic exenteration for advanced pelvic malignancies during the 15-year period from 1969 to 1984. Thirty-two had colorectal cancers, eleven cervical, seven bladder, and six vulvar; in twelve the cancers were in miscellaneous pelvic sites. Forty-five exenterations were done with intent to cure, and twenty-three for palliation of patients with bulky, necrotic tumors that had caused symptomatic fistulae, local sepsis, chronic bleeding, or severe localized pain. The total 30-day postoperative mortality was 4.4% (3/68). The 5-year survival rate of patients who underwent curative exenteration was 33% (median 27 months). Pelvic exenteration appears to be a feasible surgical procedure for a variety of advanced malignancies as well as for palliation of severely symptomatic patients.

Detection of pancreatic tumors by ultrasound during surgery.

Real-time B-mode ultrasonic scanning was performed during 14 operations for pancreatic tumors. All operations were for adenocarcinoma, except in one patient with a Zollinger-Ellison tumor. The ultrasonic tissue appearance of pancreatic carcinoma was not specific. However, ultrasonic signs of pancreatic duct dilation, striction or invasion of the superior mesenteric veins, and common bile duct involvement may help to establish the diagnosis of malignancy. A triad of ultrasound signs indicative of malignant obstruction of the common bile duct consisted of (1) dilation, (2) absence of biliary stones, and (3) a distinctive termination pattern of the duct. Operative ultrasound was used to guide a biopsy needle to obtain pancreatic tissue samples. The Zollinger-Ellison tumor of the pancreas produced a sonolucent appearance that clearly distinguished it from the surrounding tissue.

Ultrasonic imaging during biliary and pancreatic surgery.

Real-time ultrasound scanning was used during operations on the biliary tract and pancreas. The principal application in biliary surgery was to evaluate the common bile duct for presence of calculi. Our initial experience indicates that operative ultrasonography compares favorably with operative cholangiography. In pancreatic operations, ultrasound has been helpful in the management of pseudocysts and chronic pancreatitis. For pseudocysts, ultrasonography has indicated cyst wall thickness and the presence of adjacent anatomic structures. Ultrasound has distinguished the fluid loculations of the pseudocyst from swelling due to inflammatory edema. In surgery for chronic pancreatitis, ultrasonography has revealed the size and location of pancreatic ducts. This information has been useful in helping select sites for internal drainage of pseudocysts and in chronic pancreatitis with ductal dilatation. Operative ultrasonography is a relatively simple procedure which has the potential for providing the surgeon with early information and decreasing the need for dissection and radiographic imaging.