Non-harmonic potential of a single beam optical trap.

Since the invention of optical traps based on a single laser beam, the potential experienced by a trapped specimen has been assumed harmonic, in the central part of the trap. It has remained unknown to what extent the harmonic region persists and what occurs beyond. By employing a new method, we have forced the trapped object to extreme positions, significantly further than previously achieved in a single laser beam, and thus experimentally explore an extended trapping potential. The potential stiffens considerably as the bead moves to extreme positions and therein is not well described by simple Uhlenbeck theories.

New chromogenic agar medium for the identification of Candida spp.

A new chromogenic agar medium (Candida diagnostic agar [CDA]) for differentiation of Candida spp. is described. This medium is based on Sabouraud dextrose agar (Oxoid CM41) and contains (per liter) 40.0 g of glucose, 10.0 g of mycological peptone, and 15.0 g of agar along with a novel chromogenic glucosaminidase substrate, ammonium 4-(2-[4-(2-acetamido-2-deoxy-beta-D-glucopyranosyloxy)-3-methoxyphenyl]-vinyl)-1-(propan-3-yl-oate)-quinolium bromide (0.32 g liter(-1)). The glucosaminidase substrate in CDA was hydrolyzed by Candida albicans and Candida dubliniensis, yielding white colonies with deep-red spots on a yellow transparent background after 24 to 48 h of incubation at 37 degrees C. Colonies of Candida tropicalis and Candida kefyr were uniformly pink, and colonies of other Candida spp., including Candida glabrata and Candida parapsilosis, were white. CDA was evaluated by using 115 test strains of Candida spp. and other clinically important yeasts and was compared with two commercially available chromogenic agars (Candida ID agar [bioMerieux] and CHROMagar Candida [CHROMagar Company Ltd.]). On all three agars, colonies of C. albicans were not distinguished from colonies of C. dubliniensis. However, for the group containing C. albicans plus C. dubliniensis, both the sensitivity and the specificity of detection when CDA was used were 100%, compared with values of 97.6 and 100%, respectively, with CHROMagar Candida and 100 and 96.8%, respectively, with Candida ID agar. In addition, for the group containing C. tropicalis plus C. kefyr, the sensitivity and specificity of detection when CDA was used were also 100%, compared with 72.7 and 98.1%, respectively, with CHROMagar Candida. Candida ID agar did not differentiate C. tropicalis and C. kefyr strains but did differentiate members of a broader group (C. tropicalis, C. kefyr, Candida lusitaniae plus Candida guilliermondii); the sensitivity and specificity of detection for members of this group were 94.7 and 93.8%, respectively. In addition to the increased sensitivity and/or specificity of Candida detection when CDA was used, differentiation of colony types on CDA (red spotted, pink, or no color) was unambiguous and did not require precise assessment of colony color.

Vaginal vault suspension and enterocele repair by Richardson-Saye laparoscopic technique: description of training technique and results.

OBJECTIVES: To describe the Richardson-Saye technique for laparoscopic vaginal vault suspension and enterocele repair (vaginal apex reconstruction) and the appropriate training needed for performance of this technique. METHODS: Before using this technique, Drs Carter, Winter, and Mendelsohn first received training by observation of skilled surgeons performing the procedure, attending courses, and finally being tutored and proctored by Dr Saye on the appropriate performance of the technique. They then used this technique to surgically treat eight patients, 42 to 85 years of age, mean age 62 years, between March and September of 1999. RESULTS: We included eight patients in this study who underwent the Saye-Richardson vaginal vault suspension and enterocele repair (apical vaginal vault reconstruction) by the suture technique. In all patients at six-month follow-up, the vaginal apex remains intact and well supported. We describe here the entire vaginal vault suspension and enterocele repair procedure with all its relevant details. CONCLUSION: Laparoscopic reconstruction of the disrupted vaginal apex followed by reattachment to the previously broken uterosacral ligament with the use of permanent suture provides a secure and anatomically correct vault suspension. Before performing this technique, physicians should undergo proper training, including observation, courses, tutoring, and proctorship by a surgeon experienced in performing this technique.

Sites in the United States contaminated with radioactivity.

Over the century that radioactive materials have been mined, processed, produced, and utilized, many sites across the United States have become contaminated. Such sites include bases and installations of the Department of Defense, weapons production and research facilities of the Department of Energy, properties under the authority of other Federal agencies, privately-owned and governmental facilities that are licensed by the Nuclear Regulatory Commission and its Agreement States, and sites licensed by or the responsibility of states. This review reports on aspects of work by the Environmental Protection Agency, the Department of Defense, the Department of Energy, the Nuclear Regulatory Commission, and others to identify sites contaminated with radioactive materials. It also describes the principal programs that have been instituted to deal with them.

Funding realities: child abuse diagnostic evaluations in the health care setting.

OBJECTIVE: This study examines staffing, funding sources, reimbursement, and financing of medically-oriented child protection teams. METHOD: A 16-item questionnaire on the composition, size, and services of the team, program costs, revenue sources, reimbursement rates, and perceptions of funding stability was mailed to a sample of 118 medically-oriented child protection teams. RESULTS: After excluding 10 programs, an overall response rate of 68% was obtained. Teams varied in configuration, services, charges, and funding. Over 50% identified funding as being important, yet, demonstrated varying levels of awareness of budget and reimbursement issues. Many generally relied on patient care reimbursement from health care and government payers. Some programs seemed to be doing well financially while others were struggling. Approximately one-third of the respondents indicated that funding was unstable. CONCLUSIONS: Many programs are innovatively knitting together patch-works of funding and support to serve children and families in need. Team leaders should increase their knowledge of fiscal issues in order to be effective advocates at the institutional level for continued team support. A potential way of accomplishing this would be to utilize the existing structure of a national professional association and its national meeting to provide a forum for relatively successful programs to showcase their "ideal models" of team financing.

A novel chromogenic ester agar medium for detection of Salmonellae.

A novel agar medium, chromogenic Salmonella esterase (CSE) agar, for the differentiation of salmonellae is described. The agar contains peptones and nutrient extracts together with the following (grams per liter unless otherwise specified): 4-[2-(4-octanoyloxy-3, 5-dimethoxyphenyl)-vinyl]-quinolinium-1-(propan-3-yl carboxylic acid) bromide (SLPA-octanoate; bromide form), 0.3223; lactose, 14. 65; trisodium citrate dihydrate, 0.5; Tween 20, 3.0; ethyl 4-dimethylaminobenzoate, 0.035% (wt/vol), novobiocin, 70 mg liter-1. The key component of the medium is SLPA-octanoate, a newly synthesized ester formed from a C8 fatty acid and a phenolic chromophore. In CSE agar, the ester is hydrolyzed by Salmonella spp. to yield a brightly colored phenol which remains tightly bound within colonies. After 24 h of incubation at 37 or 42 degreesC, colonies of typical Salmonella spp. were burgundy colored on a transparent yellow background, whereas non-Salmonella spp. were white, cream, yellow or transparent. CSE agar was evaluated by using a panel of strains including a high proportion of Salmonella and non-Salmonella strains giving atypical reactions on other differential agars. The sensitivity (93.1%) of CSE agar for non-typhi salmonellae compared favorably with those of Rambach (82. 8%), xylose-lysine-deoxycholate (XLD; 91.4%), Hektoen-enteric (89.7%), and SM ID (91.4%) agars. The specificity (93.9%) was also comparable to those of other Salmonella media (SM ID agar, 95.9%; Rambach agar, 91.8%; XLD agar, 91.8%; Hektoen-enteric agar, 87.8%). Strains of Citrobacter freundii and Proteus spp. giving false-positive reactions with other media gave a negative color reaction on CSE agar. CSE agar enabled the detection of >30 Salmonella serotypes, including agona, anatum, enteritidis, hadar, heidelberg, infantis, montevideo, thompson, typhimurium, and virchow, which accounted for 91.8% of the salmonella isolates recorded by the Public Health Laboratory Service (Colindale, London, England) for 1997.

The accuracy of dental radiographic techniques used for evaluation of implant fixture placement.

Periapical, panoramic, linear tomographic, and computerized tomographic radiographs were made of a partially dentate human mandible with four implants in place. Measurements taken from the radiographs and computer-generated images were compared to measurements made directly on the cross-sectioned test specimen. Periapical radiographs produced the most accurate measurements. Computerized and linear tomographic images provided the unique advantage of cross-sectional views of anatomic structures, but image blurring inherent to linear tomography and volume-averaging error inherent to computerized tomography affected the accuracy of measurements made from these images. The use of a dense dimensional reference object helped to compensate for radiographic distortion and is appropriate when projection radiographic techniques are used. The CT reference scale provided the most accurate method for interpreting measurements made from the computerized tomogram. The use of a dense dimensional reference object is inappropriate with CT because of its volume-averaging error.

Bone grafting and guided bone regeneration for immediate dental implants in humans.

This study evaluated bone regeneration and osseointegration of hydroxyapatite (HA) coated and titanium plasma sprayed (TPS) implants placed in sockets immediately after extraction in 36 adults, mean age 55.2 years (range 26 to 81 years). Twelve TPS and 10 HA-coated implants in 20 patients were grafted with demineralized freeze-dried bone allograft (DFDBA), covered with a barrier material, and the facial flap coronally positioned to attain primary closure (experimental). The remaining 11 TPS and 10 HA-coated implants were placed similarly, except that no DFDBA was used (control). Osseous structures were measured at the initial placement and 6-month re-entry surgeries. At the 6-month re-entry, all implants placed were clinically osseointegrated. Bone resorption at the most coronal socket crest was -1.53 mm for the grafted group and -1.59 mm for the control group. Crestal bone apposition of 1.39 mm was noted at the most apical socket crest (ASC) for the grafted group, whereas crestal resorption of -0.11 mm was noted in the ungrafted control group (P < 0.02). Bone fill from the base of the deepest osseous defect was 5.68 mm for the grafted group and 3.18 mm for the control group (P < 0.04). Complete resolution of osseous defects occurred at 15 of 22 sites in the grafted group and at 9 of 21 sites in the control group. Clinical exposure of the barrier material and a subsequent inflammatory response at 27 of 43 sites, requires removal of the material prior to the 6-month re-entry and was associated with significantly more bone loss at the ASC sites (P < 0.01). There was no significant difference for any of the parameters when comparing the TPS with the HA-coated implants.

Febrile infants at low risk for serious bacterial infection--an appraisal of the Rochester criteria and implications for management. Febrile Infant Collaborative Study Group.

OBJECTIVE: Prospective studies were conducted to test the hypothesis that infants unlikely to have serious bacterial infections (SBI) can be accurately identified by low risk criteria. METHODS: Febrile infants (rectal T > or = 38 degrees C) < or = 60 days of age were considered at low risk for SBI if they met the following criteria: 1) appear well; 2) were previously healthy; 3) have no focal infection; 4) have WBC count 5.0-15.0 x 10(9) cells/L (5000-15,000/mm3), band form count < or = 1.5 x 10(9) cells/L (< or = 1500/mm3), < or = 10 WBC per high power field on microscopic examination of spun urine sediment, and < or = 5 WBC per high power field on microscopic examination of a stool smear (if diarrhea). The recommended evaluation included the culture of specimens of blood, cerebrospinal fluid, and urine for bacteria. Outcomes were determined. The negative predictive values of the low risk criteria for SBI and bacteremia were calculated. RESULTS: Of 1057 eligible infants, 931 were well appearing, and, of these, 437 met the remaining low risk criteria. Five low risk infants had SBI including two infants with bacteremia. The negative predictive value of the low risk criteria was 98.9% (95% confidence interval, 97.2% to 99.6%) for SBI, and 99.5% (95% confidence interval, 98.2% to 99.9%) for bacteremia. CONCLUSIONS: These data confirm the ability of the low risk criteria to identify infants unlikely to have SBI. Infants who meet the low risk criteria can be carefully observed without administering antimicrobial agents.

Combined dental implant and guided tissue regeneration therapy in humans.

This study evaluated wound healing and osseointegration of dental implants placed in immediate postextraction sockets in humans. Ten healthy adults had one or more teeth extracted and replaced with ITI dental implants, which were centered in the residual socket and covered with a polytetrafluoroethylene membrane and a flap to attain primary closure. Measurements were made to document the relationship of bone to implant at the time of implant placement and at the 6-month reentry. All implants were clinically osseointegrated at the 6-month reentry procedure; narrow bony defects showed complete bone fill, while wide defects showed partial bone fill. There was less bone regeneration in areas of thin cortical bone or preexisting dehiscences and in implant sites with early membrane exposure. Implants placed in immediate postextraction sockets demonstrated successful osseointegration with irregular bone-healing patterns, which were related to variations in existing bony anatomy and socket location.

Comparative study of collagen and expanded polytetrafluoroethylene membranes in the treatment of human class II furcation defects.

The purpose of this study was to compare the changes in clinical attachment when either a non-resorbable ePTFE membrane or an absorbable collagen membrane was used as a barrier during surgical treatment of class II molar furcation defects. Thirteen patients, mean age 43.2 years, with two comparable class II molar defects were treated using a split mouth design. Pre-surgical standardized probings were made using an automated probe at a constant force of 25 grams. Four to 6 weeks after initial therapy, the furcations were surgically debrided, the membranes placed to occlude separate furcation defects in each patient, and the sites closed. The ePTFE membrane was removed 6 weeks after placement. Six months postsurgery, the clinical measurements were repeated. Student t test was used to compare the results. There were no significant differences in the mean initial measurements between the treatment groups. The mean decrease in vertical probing depth was 1.40 +/- 1.68 mm for the collagen treated sites and 1.07 +/- 0.81 mm for the ePTFE treated sites. The decrease in horizontal probing depth was 1.49 +/- 1.97 mm for the collagen treated sites and 0.79 +/- 2.16 mm for the ePTFE treated sites. No significant differences were found between any of the clinical parameters measured. Based on the results of this short-term clinical study, the absorbable collagen membrane was statistically equivalent to the non-resorbable ePTFE membrane in the clinical resolution of class II furcation defects.

The dimensions of the human dentogingival junction.

This study examined the naturally occurring dimensions of the dentogingival junction in 10 adult human cadaver jaws. The connective tissue attachment, epithelial attachment, loss of attachment, and sulcus depth were measured histomorphometrically for 171 tooth surfaces. Mean measurements were 1.34 +/- 0.84 mm for sulcus depth; 1.14 +/- 0.49 mm for epithelial attachment; 0.77 +/- 0.32 mm for connective tissue attachment; and 2.92 +/- 1.69 mm for loss of attachment. These dimensions, as measured in this study, support the concept that the connective tissue attachment is a variable width within a more narrow distribution and range than the epithelial attachment, sulcus depth, or loss of attachment. The level of the loss of attachment was not predictive of the connective tissue attachment length.

The rectovaginal septum revisited: its relationship to rectocele and its importance in rectocele repair.

Using the descriptions of Uhlenhuth, and Milley and Nichols, we have been able to identify a sheet of strong connective-type tissue between the rectum and vagina. This layer has been named the rectovaginal septum, referred to, by some, as the rectovaginal fascia. As it is considered to be analogous to the rectovesical septum in men, first described by Denovilliers, some refer to it as Denonvilliers' fascia in the female. This layer is immediately beneath the vaginal mucosa and clearly is what many would consider part of the vaginal wall. Its principal attachments are peripheral--it merges superiorly with the cardinal/uterosacral complex, fuses laterally with the fascia over the levator muscle, and merges distally into the perineal body. Histologically, it contains collagen that is quite dense in places, some strands of smooth muscle, and a very dense network of heavy elastin fibers. It is this layer that acts as a supporting structure for the perineal body and prevents the rectum from bulging into the vagina. Rectoceles represent a defect in this layer that allows the rectum to bulge inward. The defects are usually isolated breaks that can be repaired directly with excellent and predictable results.

Interpretation of linear and computed tomograms in the assessment of implant recipient sites.

Tomography is a radiographic process that produces cross-sectional images of bony structures within the body. The purpose of this study was to evaluate the accuracy of diagnostic measurements made by dental implant team members from linear tomograms of human cadaver mandibles. Five partially edentulous cadaver mandibles were radiographed using linear tomography (LT) and computer-assisted tomography (CT). From the tomograms, each of four team members traced the perceived outer circumference of the mandible and the inferior alveolar canal. Tomogram tracings were compared to each other and to the equivalent CT cross-sectional image to determine the precision of the measurements. One mandible was sectioned to verify the accuracy of the CT images. Repeated measures analysis of variance of the measurements made from the LT and CT scans showed significant statistical differences between team members. Multiple cross-sectional views facilitated identification of the inferior alveolar canal in the majority of CT scans, whereas image blurring inherent to LT resulted in the inability of team members to identify the canal in 14% to 50% of the images. Volume averaging within the CT slice aperture was found capable of producing a magnification error of short dense objects. CT and LT must both be interpreted cautiously because of innate technique objects. CT and LT must both be interpreted cautiously because of innate technique pecularities that can lead to measurement errors. The wide variation in interpretation of the linear tomograms and frequent inability to identify the inferior alveolar canal made this technique less valuable than the reformatted CT when planning dental surgical procedures.

Risedronate activity in the fetal and neonatal mouse.

Otosclerosis, chronic otitis media with and without cholesteatoma, and Paget's disease of bone are just a few of the many diseases of the ear that exhibit abnormalities of bone modeling and remodeling. These diseases result in chronic infection, vestibular dysfunction, and hearing loss. Bisphosphonates are a promising new class of drugs potentially useful in the treatment of these disorders. Currently used in diseases with high rates of bone turnover (Paget's disease of bone, hypercalcemia of malignancy, and osteoporosis), they have been found to be strong inhibitors of bone resorption. A third generation bisphosphonate, 2-(3-pyrindyl)-hydroxyethylidene bisphosphonate (risedronate) is being investigated for toxicity, increased efficacy, and oral administration. In this study the in vitro and in vivo anti-resorptive activity of risedronate was quantified by measuring calcium release in a neonatal mouse calvarial culture system. This model was used to test direct in vitro effects, in vivo exposure in neonatal mice, and the possible effects of in utero and lacteal exposure. Calcium release activated by parathyroid hormone (PTH) was significantly inhibited when risedronate was only present in the pre-incubation media. When risedronate was administered subcutaneously to neonatal mice it resulted in a significant decrease in PTH-activated calcium release in explanted calvaria in vitro. Transplacental and lactational transfer of biologically effective risedronate was not demonstrated in this study; however, a paradoxic increase in PTH-stimulated calcium release in vitro from calvaria theoretically exposed transplacentally and lacteally was noted. This effect was unexplained by the data.

Small versus large particles of demineralized freeze-dried bone allografts in human intrabony periodontal defects.

Various particle sizes of demineralized freeze-dried bone allograft (DFDBA) are currently used to treat patients with periodontal osseous defects. However, the effect of particle size on the healing of human intrabony periodontal defects is unknown since there have been no direct clinical comparisons. The purpose of this study was to compare the bony defect resolution obtained using two different particle size ranges of DFDBA. Cortical bone from a single donor was processed and ground to final particle sizes of 250 mu to 500 mu or 850 mu to 1,000 mu using an analytic mill. Paired interproximal intrabony periodontal defects in 11 patients were grafted with DFDBA. Soft and hard tissue measurements were made using an electronic constant-force probe at the initial and reentry surgeries. Treated sites in 10 patients were reevaluated by reentry approximately 6 months postoperatively. Mean bony defect fill was 1.66 mm for the large particle group and 1.32 mm for the small particle group. There was no statistically significant difference in bony fill between defects grafted with the different particle sizes of DFDBA when used in humans.

Comparison of several new chromogenic galactosides as substrates for various beta-D-galactosidases.

The kinetic characteristics of beta-galactosidases from bovine liver and testes, Escherichia coli, Aspergillus niger and Jack bean were studied using five newly-developed colorimetric substrates. All the chromophores released by enzyme hydrolysis had high extinction coefficients in the visible region of the spectrum. Varying amounts of substrate inhibition were found with each of these substrates (VBzTM-Gal, VLM-Gal, VLPr-Gal, VQM-Gal and VQPr-Gal), but this was not a significant problem if the correct assay conditions were used. The substrates attached particularly tightly to the active centre of E. coli beta-D-galactosidase resulting in low Km values. The data suggest that the chemical properties of the heterocyclic portion of the aglycone distant from the glycosidic oxygen do not affect the substrate specificity and the substrate inhibition can be attributed to interactions not involving the catalytic site. When the product of the maximum observed velocity (Vm) and the molar absorption coefficient is calculated for each substrate, the relative merits of the substrates for the assay of each enzyme can be assessed. The beta-D-galactosidases from fungal and bacterial sources hydrolysed the substrates most efficiently, indicating that they may be of particular value in areas of molecular biology and biotechnology.

Thick free gingival and connective tissue autografts for root coverage.

Studies have shown partial to complete root coverage of denuded root surfaces with the use of thick free gingival autografts (FGGs) or subepithelial connective tissue autografts (CTGs). The purpose of this study was to determine which technique would result in more predictable root coverage of Miller Class I and II marginal tissue recession defects. Paired defects in 10 patients were randomly selected for treatment with either the FGG or the CTG. With stents as reference points, soft tissue recession was measured with a calibrated probe presurgically and 3 and 6 months postsurgically. No significant differences between paired sites in presurgical defect dimensions were found. One patient was dropped from the study for noncompliance with postoperative instructions. The mean percentage of root coverage for the CTG 3 and 6 months postsurgery for the remaining 9 patients was 78% and 80%, respectively. The mean percentage of root coverage for the FGG was 43% at both periods. The difference in root coverage between the 2 techniques was significant (P < 0.03). Complete root coverage was gained in 5 of 9 CTGs but only in one of 9 FGGs. Both techniques resulted in a significant improvement in keratinized tissue and probing attachment level, with most of the changes having occurred during the first three months postoperatively. Results suggest that the CTG may provide a greater percentage of root coverage than the FGG and that both techniques will effectively increase the width of keratinized tissue.