The effect of sudden inversion stress on EMG activity of the peroneal and tibialis anterior muscles in the chronically unstable ankle

Residual symptoms resulting from recurrent episodes of inversion-type ankle sprains may be attributed to a decreased neuromuscular response of the peroneal or tibialis anterior muscles, thereby increasing the probability for reinjury. The purpose of this study was to examine the electromyographic (EMG) response time of the peroneal and tibialis anterior muscles in response to sudden plantar flexion/inversion stress in the chronically functional unstable and normal ankle. Subjects for this study consisted of 13 athletically active individuals (five males and eight females, mean age = 19.2 +/- 1.51 years) with a previous history of a unilateral inversion-type ankle sprain. A specially designed platform that allows each foot to drop into plantar flexion/inversion from a standing neutral position was used. Reaction time in milliseconds for the peroneal and tibialis anterior muscles to sudden plantar flexion/inversion was measured via surface EMG. A paired t test was performed with the Bonferroni-Dunn correction factor to determine differences between the peroneal and tibialis anterior as well as between the chronically unstable and contralateral normal ankle. The results indicated no significant differences between the stable and unstable ankles for the peroneal or the tibialis anterior muscles. The results also indicated no significant differences existed between the tibialis anterior and peroneal muscles in either the stable or unstable ankles. The findings from the present study suggest that self-reported functional ankle instability may not result in a diminished reflex response time of the peroneal and tibialis anterior muscles to sudden plantar flexion/inversion stress.

Cytotoxicity of copper complexes of 2-furaldehyde oxime derivatives in murine and human tissue cultured cell lines

The copper complexes of furan oxime derivatives were found to be potent cytotoxic agents in both murine and human tissue cultured cell lines which were either suspended or solid tumors. The ED50 values were frequently improved over the clinically useful antineoplastic agents. These copper complexes of 2-furaldehyde oximes were effective inhibitors of L1210 lymphoid leukemia DNA synthesis followed by RNA synthesis. Purine synthesis regulatory enzyme activities were markedly reduced by the compounds with marginal inhibition of t-RNA polymerase, and nucleoside kinases activities. L1210 DNA topoisomerase II activity was markedly reduced with IC50 values better than the standard VP-16, etoposide. Yet, the copper complexes caused no further protein linked breaks than VP-16 did, but did block phosphorylation activation of the topoisomerase II enzyme.

The bacillus subtilis dinR gene codes for the analogue of Escherichia coli LexA. Purification and characterization of the DinR protein

The Bacillus subtilis dinR gene encodes a 23-kDa protein that shares about 34% homology with the Escherichia coli LexA protein. We have purified the dinR gene product to near homogeneity, and we describe its activities. The purified DinR protein binds specifically to the promoter regions of three B. subtilis SOS genes: dinB, dinC, and recA. Electrophoretic mobility of DinR-promoter complexes in each case is identical to that of promoters bound by the B. subtilis SOS repressor (Lovett, et al., (1993) J. Bacteriol. 175, 6842-6849). Analysis of hydroxyl radical footprints of DinR bound to the dinC promoter indicates that DinR interacts with one side of the DNA providing access to the consensus operator site (5'-GAACN4GTTC-3') within two adjacent major grooves. Consistent with its proposed role as a transcriptional repressor, purified DinR displaces B. subtilis RNA polymerase from the recA promoter and represses transcription of the recA gene in vitro. We also show that purified DinR protein undergoes general base-catalyzed autodigestion as well as RecA-mediated cleavage at the peptide bond between Ala-91 and Gly-92. Corresponding to its cleavage by activated RecA following DNA damage, the level of DinR is significantly reduced in RecA+ B. subtilis cells following exposure to mitomycin C. Thus, the DinR protein is structurally and functionally analogous to the E. coli LexA protein, and accordingly, we propose renaming the protein B. subtilis LexA.

Free and complexed prostate-specific antigen serum ratios to predict probability of primary prostate cancer and benign prostatic hyperplasia

OBJECTIVES

Ratios of free to total prostate-specific antigen (f/t PSA ratio) improved differentiation of benign prostatic hyperplasia (BPH) from prostate cancer (CaP). Using sera obtained at least 1 month prior to biopsy-confirmed diagnosis and logistic regression adjusted for disease prevalence, probability curves are constructed to predict the presence of CaP.

METHODS

The patient population included 122 (44%) BPH sera and 155 (56%) prostate carcinoma sera collected prior to any therapy. The total PSA range = 2.0-20.0 ng/mL; median age = 69 years. External reference standards for both free and total PSA assays were used to standardize the assays and correct the ratio. Probability curves and tables for cancer incidence were formulated for a subset of the total test population (total PSA range = 2.0-10.0 ng/mL; 98 BPH, 118 CaP patients) by using logistic regression and prior cancer prevalence statistics derived from a published patient screening study.

RESULTS

Median f/t PSA ratios were 0.18 and 0.12 in the overall sample and 0.19 and 0.12 in the subset for BPH and CaP, respectively (P = 0.0001). The median total PSA concentrations for BPH and CaP were 5.8 and 6.7 ng/mL when total PSA range = 2.0-20.0 ng/mL and were 4.9 and 5.9 ng/mL when total PSA range = 2.0-10.0, respectively.

CONCLUSIONS

Cancer probability curves were constructed to help guide decisions concerning biopsy and other aspects of prostate cancer disease management. Further validation of this approach in another series of patients is necessary and is planned.

Ability to predict biochemical progression using Gleason score and a computer-generated quantitative nuclear grade derived from cancer cell nuclei

OBJECTIVES

To determine the ability to predict prostate cancer progression using shape, size, and chromatin texture nuclear grading features preselected by logistic regression analyses based on expert-selected prostate cancer cell nuclei captured using a computer-assisted image analysis system.

METHODS

One hundred fifteen patients with clinically localized prostate cancer were identified at the Johns Hopkins medical institutions. The mean follow-up period was 10.4 +/- 1.7 years in 70 patients without disease progression, whereas the mean time to progression for the entire group was 3.8 +/- 2.5 years. Using 5-microns Feulgen-stained tissue sections, approximately 150 cancer cell nuclei were selected and captured for each case using a CAS-200 Image Analysis System. Thirty-eight different nuclear morphometric descriptors (NMDs) were calculated for each cell nucleus. The variance of the NMDs for each tumor was examined by univariate and multivariate logistic regression analyses and by Cox survival analyses to assess their ability to predict prostate cancer progression.

RESULTS

Postoperative Gleason scoring was significantly correlated with disease progression (P < 0.00001; sensitivity, 73%; specificity, 84%; receiver operating characteristic curve area under the curve (ROC-AUC), 83%). Using backward stepwise logistic regression at a stringency of P < 0.05, the variances of 11 of the NMDs were found to be multivariately significant for progression prediction (P < 0.00001; sensitivity, 78%; specificity, 83%; ROC-AUC, 86%). A single value, termed the quantitative nuclear grade (QNG), was created from the variances of these, 11 multivariately significant NMDs using the logistic regression function. The QNG and the postoperative Gleason score were combined to create a model for the prediction of progression having a sensitivity of 89%, specificity of 84%, and ROC-AUC of 92%. These two parameters (QNG and Gleason score) clearly separated the patient sample into three statistically distinct risk groups and predicted the time to progression on the basis of Kaplan-Meier survival probability analysis.

CONCLUSIONS

The QNG, combined with the postoperative Gleason score, may assist in the more accurate stratification of patients undergoing radical prostatectomy into low-, moderate-, and high-risk groups for cancer recurrence and may permit the early initiation of adjuvant therapy.

An algorithm for predicting nonorgan confined prostate cancer using the results obtained from sextant core biopsies with prostate specific antigen level

PURPOSE

We determined the enhanced ability to predict nonorgan confined prostate cancer using several histopathological and quantitative nuclear imaging parameters combined with serum prostate specific antigen (PSA).

MATERIALS AND METHODS

Several independent pathological and quantitative image analysis variables obtained from sextant biopsy specimens, as well as preoperative PSA were used. The study population included 210 patients with pathologically staged disease (192 with PSA). All variables were examined by univariate and multivariate logistic regression analyses to assess ability to predict disease organ confinement status.

RESULTS

Univariate logistic regression analysis demonstrated that, in decreasing order, quantitative nuclear grade, preoperative PSA, total percent tumor involvement, number of positive sextant cores, preoperative Gleason score and involvement of more than 5% of a base and/or apex biopsy were significant (p < or = 0.006) for prediction of disease organ confinement status. Backward stepwise logistic regression was applied to these univariately significant variables, including deoxyribonucleic acid ploidy, to calculate a multivariate model for prediction of disease organ confinement status. This algorithm had a sensitivity of 85.7%, specificity 71.3%, positive predictive value 72.9%, negative predictive value 84.7% and area under the receiver operating characteristic curve 85.9%.

CONCLUSIONS

Information from pathological study of sextant prostate biopsies, preoperative PSA blood test and a new image analysis variable termed quantitative nuclear grade can be combined to create a multivariate algorithm that can predict more accurately nonorgan confined prostate cancer compared to previously reported methods.

Development of secondary structure, growth characteristics and cytogenetic analysis of human transitional cell carcinoma xenografts in scid/scid mice

PURPOSE

The growth of human bladder transitional cell carcinoma (TCC) in scid/scid mice was examined.

MATERIALS AND METHODS

Cystocopically obtained TCC biopsies were implanted in scid/scid mice, and successful xenografts were compared with original tumors for growth and genetic characteristics.

RESULTS

Low grade papillary tumors formed fluid-filled pseudobladders lined with malignant urothelium and papillary fronds containing fibrovascular cores recruited from the murine host. High grade xenografts grew without these secondary structures. When compared with the patient tumors, xenograft growth fractures, as measured by proliferating cell nuclear antigen, p53 expression and ploidy, were similar in each.

CONCLUSIONS

The scid/scid xenografts maintain phenotype and architecture. This model may be useful for studying factors determining tumor grade, angiogenesis and tissue organization.

Physical modelling of hip joint forces in stair climbing

A test device has been developed and validated to simulate physiologic loading of the hip during stair climbing. Forces about the hip joint were measured in static simulations of stair climbing using simulated extensor, abductor and adductor muscle groups to support the joint. Femoral flexion angle (to model step length and height) and applied hip flexion moment (to model trunk lean) were varied to examine the effects of different loading conditions on the hip. In stair climbing the maximum total joint force was six times body weight at 34 degrees of femoral flexion and 60 N m of hip flexion moment. Joint forces increased with hip flexion moment and varied little with femoral flexion angle, except for the posteriorly directed force. This component, which twists implants about the femoral shaft, increased with femoral flexion angle but changed little with hip flexion moment.

A Novel X-ray Diffractometer to Study the Texture of Materials

An X-ray energy-dispersive diffraction technique to study the texture of materials using synchrotron radiation has been developed. The design and commissioning of the diffraction instrument are described. The technique was first applied to study a drawn-wire aluminum sample which has a well known deformation texture. To demonstrate its capability further, results obtained from an erbium evaporated thin film are also presented.

Choosing practice management software. How sophisticated should you get?

In order to make informed purchasing decisions about practice management software, dental professionals must first assess their needs by determining the types of tasks they expect from a system and then compare that list against the features offered by each system. Because technology is changing rapidly, much of what was advanced a few years ago is now considered basic. Three general levels of sophistication are discussed, with attention to the complexity of features that can be expected to be found at each level.

Guided tissue regeneration using a biodegradable barrier membrane for new attachment: a clinical, histologic, and histometric study in dogs

Although nonbiodegradable barrier membranes have proven partially successful in achieving regeneration of lost periodontium through the principles of guided tissue regeneration, their use requires a second surgical procedure for their removal. The results of a study, in which a biodegradable collagen membrane was used to treat dehiscence defects in dogs, are presented. The membrane was an effective barrier to the downgrowth of gingival epithelium during the early stages of healing and tended to increase the regeneration of new cementum and connective tissue attachment. It was also biocompatible and biodegradable.

The disposition, tissue distribution, and cellular transport of N-[[(trimethylamino)boryl]carbonyl]-L-phenylalanine methyl ester in CF1 mice

The disposition and tissue distribution of 14C-labeled N-[[(trimethylamino)boryl]carbonyl]-L-phenylalanine methyl esther (1) determined in CF1 mice following i.v., p.o., and i.p. administration. Compound 1 was found to undergo rapid and extensive metabolism, and the majority of the radioactivity was found in the skin and carcass regardless of the route of administration. Approximately 55% of the radioactivity was recovered in urine and feces after 78 h; however, excretion via these routes was not complete. Degradation of compound 1 occurred at the amide bond at low pH (0.8) but at the ester bond a physiological pH. This difference in degradation was reflected in elevation of the blood radioactivity levels after p.o. administration compared to i.p. and i.v. administration.

The pregnant dental patient

This article summarizes current literature, interviews with experts and universally accepted methods of handling the dental needs of the pregnant patient. General guidelines are offered to help understand the medical constraints of the pregnant patient and provide for her care.

The cytotoxicity of 3'-aminocyanoborane-2', 3'-dideoxypyrimidines in murine and human tissue cultured cell lines

3'-Aminocyanoborane-2', 3'-dideoxythymidine (VIIa) and 3'-aminocyanoborane-2', 3'-dideoxyuridine (VIIIb) were successfully synthesized. The thymidine derivative (VIIIa) was shown to be a potent cytotoxic agent in murine and selected human suspended and solid tumor cell lines. Compound VIIIa inhibited L-1210 leukemia DNA and RNA synthesis with the protein synthesis requiring a higher concentration of drug for inhibition within 60 min. The purine pathway appeared to be the major target of Compound VIIIa with inhibition of IMP dehydrogenase and dihydrofolate reductase activities. The compound affected metabolic enzyme activities in the pyrimidine pathway as well as the nucleoside kinase activities. The DNA molecule did not appear to be target of the 3'-aminocyanoborane-2', 3'-dideoxythymidine (VIIIa), in that there was no change in ct-DNA viscosity, thermal denaturation or absorption of nucleosides of DNA nor was there any L-1210 DNA strand scission or inhibition of L-1210 DNA topoisomerase II activity when compound VIIIa was incubated at 100 microM.

Deoxyribonucleic acid ploidy analysis as a predictor of recurrence following radical prostatectomy for stage T2 disease

Deoxyribonucleic acid (DNA) ploidy image analysis was used postoperatively to predict recurrence of 112 clinically localized adenocarcinomas of the prostate. All men underwent radical retropubic prostatectomy between 1978 and 1991. Patients with positive lymph nodes or positive seminal vesicles were excluded because progression is nearly inevitable in these men. The minimum followup for men without progression was 5 years (range 5 to 15). Patients were considered to have clinically evident disease progression based on local recurrence (8%), distant metastases (4%) and/or an isolated elevation of serum prostate specific antigen (87%). Of the tumors 43% were diploid and 57% were nondiploid. In a multivariate analysis comparing grade, ploidy, capsular penetration and surgical margins, Gleason sum was the best predictor of progression (p < 0.0001). Nevertheless, a subset of patients remained with well to moderately differentiated Gleason grade tumors (Gleason sum 6 or less) who failed. DNA ploidy was able to predict recurrence in this particular group (p = 0.034). In addition, we compared different methods of tissue preparation to determine which best predicted progression. We found that ploidy analysis on tissue sections was more predictive than ploidy performed on disaggregated tissue. In summary, our study revealed that DNA ploidy analysis can offer additional prognostic information following radical prostatectomy for men with low grade prostatic adenocarcinoma.

The cytotoxic activity of 1-acyl- and 1,2-diacyl-4,4-diethyl-3,5-pyrazolidinediones

The 1-acyl- and 1,2-diacyl-4,4-diethyl-3,5-pyrazolinediones proved to be cytotoxic against the growth of a number of cell lines, including murine and human leukemias. HeLa suspended carcinoma, colon adencarcinoma SW480, KB nasopharynx and glioma tumors. Selected compounds were also active in the human lung bronchogenic MB-9812, and osteosarcoma TE418 screens. These derivatives were active in vivo in the Ehrlich ascites carcinoma screen in CF-1 mice at 8 mg/kg/day I.P. The mode of action in Tmol3 leukemia cells showed that the compounds reduced de novo synthesis of purines and pyrimidines and inhibited dihydrofolate reductase and ribonucleoside reductase activities. The DNA molecule was not a target although limited DNA strand scission may be possible.

Computing for synchrotron radiation experiments

Computing provision is of major concern to synchrotron radiation researchers. An overview is presented of the computing facilities for synchrotron radiation work at the Synchrotron Radiation Source, Daresbury Laboratory. Data acquisition, reduction and analysis are seen as an integrated activity essential for full utilization of beam time. We discuss the evolution of data-acquisition systems from stand-alone systems of limited computing power, to a unified project computing village using state-of-the-art equipment for combined-technique, high-data-rate experiments. A brief account of software packages for data reduction and analysis is also given.

Cytotoxicity of ribo-and arabinoside boron nucleosides in tissue culture cells

Ribose and arabinoside boron nucleoside derivatives were shown to be potent cytotoxic agents in murine and human suspended and solid tumor cell lines. The arabinoside derivative inhibited DNA and RNA synthesis with the protein synthesis requiring a higher concentration of drug for inhibition within 60 min. The purine pathway appeared to be the major target of the arabinoside 1 with inhibition of PRPP amido transferase and IMP dehydrogenase activities. Blockage of this pathway afforded reductions of deoxyadenosine and deoxyguanosine nucleotide pools. The DNA template did not appear to be target of the arabinoside 1, in that there was no change in DNA viscosity, thermal denaturation or absorption of nucleosides of DNA. However, compound 1 when incubated with L-1210 cells for 24 hr. showed a slight shift of the DNA in the gradient and moderate inhibition of ct-DNA topoisomerase II was demonstrated by 1 in vitro.

Guided tissue regeneration with and without decalcified freeze-dried bone in mandibular Class II furcation invasions

The purpose of this study was to compare periodontal soft and hard tissue repair using expanded polytetrafluoroethylene (ePTFE) membranes with and without decalcified freeze-dried cortical bone allografts (DFDBA). Six patients with 17 mandibular Class II buccal molar furcal invasions received oral hygiene instructions followed by scaling and root planing. Baseline soft tissue measurements with periodontal probes were made to assess probing depths (PD), recession (REC), and probing attachment levels (PAL). After non-surgical therapy, 10 teeth were randomly selected as test sites (ePTFE + DFDBA) and 7 as controls (ePTFE alone). Full-thickness flaps were elevated, and open surgical measurements were made to determine alveolar crestal height (CEJ-AC) and vertical (CEJ-BDF) and horizontal (HPDF) defect depth. The ePTFE membranes were removed at 6 weeks. After 6 months, all sites were reentered and both soft tissue and open surgical measurements recorded. The following mean changes (mm) were found for ePTFE and ePTFE + DFDBA treated sites respectively: decreased PD = 1.5, 2.2; increased REC = 1.3, 1.3; loss(-)/gain PAL = -0.2, 0.8; decreased CEJ-BDF = 3.8, 5.0; increased CEJ-AC = 0.5, 0.4; and decreased HPDF = 2.3, 2.4. None of the changes were statistically significant. The addition of DFDBA to the GTR procedure did not significantly improve any of the mean soft tissue and open surgical measurements between control (ePTFE alone) and test (ePTFE+DFDBA) groups in mandibular Class II buccal furcations. Both treatment procedures resulted in significant decreases in PD, CEJ-BDF, and HPDF and a significant increase in REC. There were no differences for PAL and CEJ-AC within control and test groups seen with this sample. Larger randomized clinical trials are needed to more fully evaluate whether combined graft and GTR procedures offer an advantage over GTR alone.