Optimization and theoretical modeling of polymer microlens arrays fabricated with the hydrophobic effect.

High-performance polymer microlens arrays were fabricated by means of withdrawing substrates of patterned wettability from a monomer solution. The f-number (f(#)) of formed microlenses was controlled by adjustment of monomer viscosity and surface tension, substrate dipping angle and withdrawal speed, the array fill factor, and the number of dip coats used. An optimum withdrawal speed was identified at which f(#) was minimized and array uniformity was maximized. At this optimum, arrays of f/3.48 microlenses were fabricated with one dip coat with uniformity of better than Deltaf/f +/- 3.8%. Multiple dip coats allowed for production of f/1.38 lens arrays and uniformity of better than Deltaf/f +/-5.9%. Average f(#)s were reproducible to within 3.5%. A model was developed to describe the fluid-transfer process by which monomer solution assembles on the hydrophilic domains. The model agrees well with experimental trends.

Characterization of a polymer microlens fabricated by use of the hydrophobic effect.

We report a means of fabricating hydrophilic domains in a hydrophobic background by lithographically patterning an adhesive hydrophobic layer. Polymer microlenses were fabricated on these substrates by use of a dip-coating technique. Various lens shapes (circular, elliptical, square) were fabricated on a variety of substrates (SiO(2), SiN, GaAs, InP, etc.), ranging in size from 2 to 500 microm in diameter, with fill factors of up to 90%. Plano-convex and double-convex lenses were fabricated, with f-numbers as low as 1.38 and 1.2, respectively. Optimum lens surfaces deviated from spherical by just +/-5 nm . The lenses are stable at room temperature and exhibit minimal degradation after 24 h at 105 degrees C. The transfer of these polymer lenses to an underlying substrate was also demonstrated.

Lower urinary tract injury during the Burch procedure: is there a role for routine cystoscopy?

OBJECTIVE: This study was undertaken to evaluate the use of intraoperative cystoscopy for the detection of incidental bladder or ureteral injuries during abdominal urethropexy procedures and to determine whether the incidence of injuries warrants the routine use of cystoscopy. METHODS: We reviewed the medical records of 109 consecutive patients who underwent abdominal urethropexy procedures between November 1990 and February 1996 at a teaching institution. Each underwent intraoperative cystoscopy. We determined the incidence of cystotomy and ureteral obstruction and attempted to determine surgical factors that might be associated with an increased risk of injury. RESULTS: Ten of 109 patients (9%) had bladder or ureteral injury, including 1 cystotomy during retropubic dissection, 6 cases of a transvesical suture noted during cystoscopy, 1 cystotomy recognized before closure, 1 case of ureteral obstruction found during cystoscopy, and 1 case of ureteral obstruction not recognized at cystoscopy. Cystoscopy allowed detection of 7 of 9 (78%) otherwise unrecognized events. The only injury that resulted in significant postoperative morbidity was the unrecognized ureteral obstruction. There was no association between incidence of lower urinary tract injuries and surgical risk factors. CONCLUSION: Intraoperative bladder or ureteral injuries during urethropexy procedures are not uncommon, with an incidence of 9% in our series. There is minimal morbidity if these injuries are detected and corrected during the operation, whereas morbidity may be significant if they remain unrecognized. With a potential for unrecognized injury in 8% of Burch procedures without the use of cystoscopy, routine use of cystoscopy during urethropexy procedures appears to be warranted.

Morbidity of osteoporosis--can estrogen use make a public health impact?

The personal morbidity and economic burden associated with osteoporosis is substantial. Estrogen has been shown to have positive effects on the prevention and treatment of this disabling disease. Information is available with regard to when to initiate estrogen therapy, how long to maintain treatment, and how best to identify those women who will benefit most from its use.

Chemosensitivity testing of human tumors using a microplate adenosine triphosphate luminescence assay: clinical correlation for cisplatin resistance of ovarian carcinoma.

An ATP luminescence assay (TCA 100) was used to measure chemotherapeutic drug sensitivity and resistance of dissociated tumor cells cultured for 6 days in serum-free medium and 96-well polypropylene microplates. Studies were performed with surgical, needle biopsy, pleural, or ascitic fluid specimens using 10,000-20,000 cells/well. ATP measurements were used to determine tumor growth inhibition. Single agent and drug combinations were evaluated using the area under the curve and 50% inhibitory concentration (IC50) results for a series of test drug concentrations. The ATP luminometry method had high sensitivity, linearity, and precision for measuring the activity of single agents and drug combinations. Assay reproducibility was high with intraassay and interassay coefficients of variation of 10-15% for percentage of tumor growth inhibition, 5-10% for area under curve, and 15-20% for IC50 results. Good correlation (r = 0.93) between the area under the curve, and IC50 results was observed. Cytological studies with 124 specimens demonstrated selective growth of malignant cells in the serum-free culture system. Studies with malignant and benign specimens also showed selective growth of malignant cells in the serum-free medium used for assay. The assay had a success rate of 87% based on criteria for specimen histopathology, magnitude of cell growth, and dose-response drug activity. Cisplatin results for ovarian carcinoma are presented for 81 specimens from 70 untreated patients and 33 specimens from 30 refractory patients. A model for interpretation of these results based on the correlation of clinical response with the area under the curve and IC50 results indicates that the assay has > 90% accuracy for cisplatin resistance of ovarian carcinoma. Additional studies are in progress to evaluate the clinical efficacy of this assay.

TCA-100 tumour chemosensitivity assay: differences in sensitivity between cultured tumour cell lines and clinical studies.

The BATLE LE TCA-100 tumour chemosensitivity assay has been used to evaluate chemotherapeutic drug sensitivity of cultured tumour cell lines. Studies were performed using test drug concentrations calibrated to discriminate sensitivity and resistance of clinical specimens. Strong sensitivity which appeared to be inconsistent with clinical experience was detected for some drugs and cell lines. Findings of strong sensitivity were consistent with basic differences between sensitivity testing cultured cell lines and clinical specimens. Results with cell lines frequently may not apply directly to clinical applications. Characterization of differences between cell lines and clinical specimens may assist in application of cell line findings to clinical trials.

Massive hydronephrosis mimicking theca lutein cysts in association with partial hydatidiform mole.

We present an unusual case of partial hydatidiform mole in which extensive, multiple cystic structures encompassing the entire right abdomen and pelvis, initially thought to represent theca lutein cysts, were subsequently shown to consist of massive unilateral right hydronephrosis. Percutaneous nephrostomy decompression bypassing the ureteropelvic obstruction revealed functional renal parenchyma.

Microbioluminometry assay: determination of erythromycin activity in plasma or serum.

A microbioluminometry assay (MBA) was developed for the quantitative analysis of erythromycin activity in human plasma or serum. The MBA method is adapted from turbidimetric methods and utilizes an enzyme-catalyzed bioluminescence reaction to quantitate the growth of Staphylococcus aureus in liquid culture medium. Statistical analysis of data obtained in method validation studies and in more than 500 assays of standard curve and control samples demonstrates consistent reproducibility and accuracy within theoretical limits. The MBA was shown to be more sensitive than agar diffusion assays with a lower limit of sensitivity less than 20.0 ng/mL and coefficients of variation less than 10%. Cumulative results of 178 assays of spiked control plasma samples in the range of 0.14-2.18 micrograms/mL show 11.2% of individual determinations are greater than +/- 15% the expected value, and 5.6% of individual determinations are greater than +/- 20% the expected value. Bioavailability profiles obtained with MBA are consistent with reported data for erythromycin. Values for 206 subject samples analyzed by MBA and agar diffusion assays showed a high degree of correlation (r = 0.9525) between the two methods. The MBA technique provided high sample throughput because of the use of microtiter plate technologies; it is also economical since it requires less sample and reagents.