Positron re-emission, reflection, and diffraction from W(100) surface at very low energies

The energy distributions of scattered and re-emitted low-energy positrons from a W(100) surface were measured as a function of incident positron energy from 0 to 25 eV. Given that tungsten has a negative work function of about -3 eV for positrons, one can envisage three scenarios of very low-energy positron scattering from such a surface. First, a positron approaching the sample surface with energy say 1 eV above the vacuum level will see a potential barrier of about 2 eV height and will be reflected back to the vacuum. Second, when the energy of incident positrons increases up to the top of the surface potential barrier (positron work function), they start entering the solid and, therefore, the reflectivity of positrons from the surface reduces. Positrons entering the solid are thermalised within few picoseconds and have a chance to escape back to the vacuum with kinetic energy about 3 eV above the vacuum level undergoing so-calledre-emission. Third, coherent scattering of low-energy positrons may occur on the crystal surface, i.e. positron diffraction. All the three scenarios of low-energy positrons scattering are studied here experimentally. Measured spectra are very sensitive to the surface conditions of the sample: they change dramatically after surface oxidation or thin film deposition.

Distal clavicle autograft for anterior-inferior glenoid augmentation: A comparative cadaveric anatomic study

INTRODUCTION

The aim of this study was to anatomically compare distal clavicle and coracoid autografts and their potential to augment anterior-inferior glenoid bone loss.

METHODS

Ten millimeters of distal clavicle and 20 mm of coracoid were harvested bilaterally from 32 cadavers. Length, weight, and height were measured and surface area and density were calculated. For each graft, ipsilateral measurements were compared and the ability to restore corresponding glenoid bone loss was calculated.

RESULTS

Distal clavicle grafts were larger than coracoid grafts with respect to length (22.3 mm versus 17.7 mm; p < 0.001), height (12.49 mm versus 9.65 mm; p < 0.001), mass (2.72 g versus 2.45 g; p = 0.0437), and volume (2.36 cm³ versus 1.96 cm³; p = 0.002). Coracoid grafts had larger widths (14.56 mm versus 10.52 mm; p < 0.001) and greater density (1.24 g/cm³ versus 1.18 g/cm³; p < 0.001). Distal clavicle surface area was greater on both the articular (2.93 cm² versus 1.5 cm²; p < 0.001) and superior surfaces (2.76 cm² versus 1.5 cm²; p < 0.001) when compared to lateral coracoid surface area.

DISCUSSION

Distal clavicle grafts were larger and restored larger bony defects but had greater variability and lower density than coracoid grafts. Clinical studies are needed to compare these graft options.

Smoking habits of UK military personnel on deployment: Exercise SAIF SAREEA 3

INTRODUCTION

Changes of environment brought about by deployments are often attributed to an increase in smoking of service personnel. Electronic cigarettes are recognised as being a viable aid to quitting smoking but are currently banned from sale in Oman and were therefore banned during exercise SAIF SAREEA 3 (SS3). This paper sought to establish whether smoking increased on this exercise and for what reasons. Also, if deployed smoking cessation services are likely to be used, if available.

METHODS

Questionnaires were distributed to deployed troops at various locations in theatre for data collection.

RESULTS

Smoking prevalence increased by 5.2% (29) in the deployed population by the end of the exercise. The largest increase was seen in those smoking 20 cigarettes a day or more, rising by 269.8% (73) with a mean increase of 9 cigarettes per day. During the exercise the number of personnel using electronic cigarettes decreased and individuals' rate of electronic cigarette use also decreased. Those who smoked less during the exercise did mainly through choice (56.8%). 50% (280) of all individuals who increased smoking habits during the exercise did so out of boredom.

CONCLUSIONS

During exercise SS3 the number of individuals who smoked and the quantity they smoked increased. The ban on electronic cigarettes in Oman and while on exercise potentially had an effect on the increased smoking habits. There is an argument to include smoking cessation material in medical modules to prevent ex-smokers from restarting, continue to aid those quitting and potentially lessen severity of increasing smoking habits while deployed.

Adoption of Intramedullary Nail Fixation for Proximal Humerus Fractures: Assessment of Surgical Efficiency and Complications

Fixation of proximal humerus fractures (PHFs) with intramedullary (IM) nails potentially is a newer, less invasive technique. The purpose of this study was to report on the early adoption results of IM nail use for PHF. Retrospective chart reviews were performed on the first 60 patients treated with IM nails for acute PHFs by two shoulder surgeons. The first 15 patients treated by each surgeon were compared with the subsequent 15 patients. Surgical and fluoroscopic times, fracture type, union, and varus collapse were compared. The average operating time decreased (p = .002). Fluoroscopy time, radiographic alignment, union rate, complications, and reoperations were not influenced. Three- and four-part fractures had a higher complication rate than two-part fractures (53% vs. 20%). When considering implementing use of IM nails for treatment of PHFs, initial cases can have outcomes and complications similar to those performed with greater experience. IM nailing appears a good treatment option for two-part PHFs. (Journal of Surgical Orthopaedic Advances 28(2):121-126, 2019).

Psychomotor Testing for Orthopedic Residency Applicants: A Pilot Study

OBJECTIVE

The purpose of this study was to develop an objective motor skills testing system to aid in the evaluation of potential orthopedic residents.

DESIGN

Participants attempted a battery of 5 motor skills tests (4 novel tests and the Grooved Pegboard [GPT] Test) in one 10-minute session. A percentile-based scoring system was created for each test based on raw scores. One-way analysis of variance was used to compare testing scores among 3 cohorts. Each novel test and overall scores were compared with GPT scores as a relative measure of validity.

SETTING

The 2015 orthopedic surgery residency interview season at an academic institution.

PARTICIPANTS

Thirty orthopedic residents and 72 nonresidents (15 community volunteers and 57 orthopedic surgery residency applicants).

RESULTS

Overall, residents performed better than nonresidents (p < 0.0001) and applicants performed worse than residents or volunteers (p < 0.0001). There were positive correlations between the GPT score and overall battery score (r = 0.63), screw and nut test (r = 0.40), and mimic a structure test (r = 0.26). The fracture reduction test and drilling test scores did not correlate to performance on the GPT.

CONCLUSIONS

Psychomotor testing for surgical applicants is an area in need of study. This investigation successfully piloted a novel battery of tests, which is easily reproducible and thus may be feasible for use in the orthopedic surgery residency interview setting. Longitudinal evaluation is required to explore correlation with future operative skill.

Abrasiveness of high-strength sutures used in rotator cuff surgery: are they all the same?

BACKGROUND

The suture-tendon interface remains the most common point of failure in rotator cuff repairs via suture pullout. Several high-strength braided sutures are available for rotator cuff surgery and are more abrasive than monofilaments. However, a comparison of these sutures has not been performed in a tissue model.

METHODS

Ninety infraspinatus sheep tendons were randomized among 9 groups of sutures (n = 10), including FiberWire (Arthrex, Naples, FL, USA), Collagen Coated FiberWire (Arthrex), Orthocord (DePuy Mitek, Raynham, MA, USA), MaxBraid (Biomet, Warsaw, IN, USA), Force Fiber (Teleflex, Research Triangle Park, NC, USA), ULTRABRAID (Smith & Nephew, Memphis, TN, USA), Phantom Fiber BioFiber (Tornier, Bloomington, MN, USA), and Ti-Cron (Syneture, Mansfield, MA), with Surgipro (Syneture) monofilament as a control. Each suture was cycled 50 times through the tendon, which was fixed to a mechanical testing system under a constant load in saline solution. The distance cut through the tendon was measured and divided by the distance of suture sliding to determine displacement (mm/cm). Twist angle and picks per inch of each suture were measured using digital photography. One-way analysis of variance was used to compare the displacement and twist angle between sutures.

RESULTS

Collagen Coated FiberWire was the most abrasive of the high-strength sutures. Four of the sutures (Collagen Coated FiberWire, Phantom Fiber BioFiber, FiberWire, Ti-Cron) had a mean displacement rate greater than 0.150 mm/cm. The remainder of the sutures had a mean displacement rate less than 0.050 mm/cm (Orthocord, Force Fiber, MaxBraid, ULTRABRAID). The difference in the displacement rates between these 2 groups was significant (P < .0001) and was related to both the twist angle and the picks per inch.

CONCLUSION

Significant differences in suture abrasiveness were identified among high-strength braided sutures and correlated with lower twist angle and lower picks per inch.

Influence of polar groups in binary polymer blends on positronium formation

The present work studied the role of the polar group unconjugated oxygen on the inhibition of positronium (Ps) formation in two binary blends made from a set of chosen constituent polymers with polar and weakly polar groups (nonpolar). The polymer blend samples of PVC-EVA and PVC-SAN were investigated by coincidence Doppler broadening and positron lifetime techniques. The strong polar acetate group in the EVA contributed to positron annihilation with electrons of unconjugated oxygen (-C(+)=O(-)) as revealed by the momentum distribution curves peaking around 17 P(L) (10(-3) m(0)c). The ortho-Ps intensity indicated the unconjugated oxygen shows about a 28% Ps reduction even in the presence of a strong Ps inhibiting halogen (Cl(-)). In contrast, this effect was not seen in the PVC-SAN blends since SAN contains a weakly polar (nonpolar) acrylonitrile group (C≡N). Our results indicate the chlorine of PVC in the blends is a major contributor to Ps inhibition through the formation of a (Cl(-)-e(+)) bound state but the unconjugated oxygen in EVA of the PVC-EVA blend also plays a similar, but lesser, role.

Auger-mediated sticking of positrons to surfaces: evidence for a single-step transition from a scattering state to a surface image potential bound state

We present the observation of an efficient mechanism for positron sticking to surfaces termed here Auger-mediated sticking. In this process the energy associated with the positrons transition from an unbound scattering state to a bound image potential state is coupled to a valence electron which can then have sufficient energy to leave the surface. Compelling evidence for this mechanism is found in a narrow secondary electron peak observed at incident positron kinetic energies well below the electron work function.

Spatially resolved scanning probe electron energy spectroscopy for Ag islands on a graphite surface

The scanning probe electron energy spectra for micron-sized Ag islands on highly ordered pyrolytic graphite substrate are measured. One- and two-dimensional relative intensity distributions for Ag or graphite plasmon peaks have been acquired and a lateral resolution of 4.8+/-2.4 microm has been achieved. It is the first time for the scanning probe electron energy spectroscopy technique to obtain the spatially resolved electron energy spectra with elemental contrast for a surface, which demonstrates the possibility of the element identification for the scanning tunneling microscope.

Miniature electrostatic electron energy analyzers and S-shaped deflector

An instrument has been developed to avoid the rotation of large electron sources and detectors in quantum single particle scattering experiments. The rotation of an electron beam has been achieved by combining three small cylindrical electrostatic electron energy analyzers in series such that the first analyzer is fixed and the other two rotate together around the exit axis of the first; it is a development from an S-shaped deflector used by Hegemann et al. [J. Phys. B 26, 4607 (1993)]. Novel design and construction, using copper, aluminum, and stainless steel parts mounted on polyvinyl printed circuit board, enabled an efficient, small-sized high vacuum compatible instrument. The characteristics and versatility of the instrument have been shown by measurements of angular and spin asymmetries of electron scattering phenomena.

Endotoxin contamination in the dental surgery

Dental waterlines contain large numbers of Gram-negative bacteria. Endotoxin, a component of such organisms, has significant health implications. Paired samples of dental unit water and the aerosols generated during dental procedures were collected, and assayed for bacteria and endotoxin levels, using heterotrophic plate counts and the Limulus amoebocyte lysate test. Consistent with published studies, the extent of bacterial contamination in the dental waters sampled for this investigation surpassed the levels associated with potable water, with counts in excess of 2.0x10(6) c.f.u. ml(-1) in some samples. Correspondingly high concentrations of endotoxin [up to 15 000 endotoxin units (EU) ml(-1)] were present in the water. A statistically significant Spearman correlation coefficient of rho=0.94 between endotoxin (EU ml(-1)) and bacterial load (c.f.u. ml(-1)) was demonstrated. All of the aerosol samples contained detectable endotoxin. Further studies of the consequences of dental endotoxin exposure, and evaluation of means to prevent exposure, are warranted.

Clinical responses in human onchocerciasis: parasitological and immunological implications

Onchocerciasis can cause severe dermal and ocular disease due, it is thought, to the events surrounding the destruction of the microfilarial stage. The evolution of papular pruritic dermatitis and punctate keratitis is clearly related to the killing of microfilariae. Other more chronic changes such as dermal and epidermal atrophy are probably due to repeated episodes of microfilarial killing. It is common to find that not all patients are, at any one time, mounting clinically obvious destructive host responses against the microfilariae, and such individuals can carry very high loads of parasites without any apparent adverse effects. The immunological basis of the differences between these types of patients forms one of the most important questions in the pathogenesis of onchocerciasis today. Various explanations are now emerging. These include immunosuppressive factors and variation in the form of Onchocerca volvulus antigens presented to the host. Clinical presentations of this disease appear to reflect variations in host responses and can be used to provide information concerning the protective immune responses an individual can mount against this parasite.

Cell adherence to microfilariae of Onchocerca volvulus: a comparative study

The conditions were examined for in vitro antibody-mediated adherence of granulocytes to microfilariae of Onchocera volvulus and Dirofilaria immitis. Reactivity in human sera from patients in endemic foci in Sudan was specific for O. volvulus and no reactions were observed with heterologous Onchocerca species or with Mansonella perstans. Microfilariae from skin, nodules or adult female worms were satisfactory targets for cell adherence, and the cells involved were almost exclusively eosinophils. The reaction was inhibited by indomethacin but not by nordihydroguaiaretic acid, an inhibitor of leukotriene production. Agents that slowed or stopped microfilarial motility (e.g. nifedipine, lidocaine, chloroquine) inhibited the reaction, probably by reducing target/cell contact. Ivermectin did not enhance the reaction, and in the absence of cells exerted only slight effects on the movement of microfilariae at higher concentrations (greater than 10 micrograms/ml). Antibody activity was labile, and did not persist well through freeze-thaw cycles. Some differences between homologous and heterologous mixtures (microfilariae/cells/serum) were seen but they could not be resolved satisfactorily. There were no apparent geographical differences between microfilariae from different foci in Sudan. In the D. immitis system neutrophils were the dominant cell type adhering to microfilariae, and the activity was stable to storage and freeze-thaw. No enhancement was detectable with diethylcarbamazine. Antibody activity was absorbable with microfilarial antigens and was reduced by agents that inhibited microfilarial motility. In dogs, adherence-mediating antibody was seen only in amicrofilaraemic animals with occult infection, and in only a minority of these sera. In humans the relationship to clinical findings was less clear, but patients with punctate keratitis were the most likely to have positive serum and were the most reactive in the assay. This system may therefore offer some insights into disease mechanisms in vivo, and its molecular mechanisms deserve further characterization.

Effect of tensile prestrain on the yield locus of 1100-f aluminium

A series of combined stress tests in torsion-tension space is carried out on thin-walled tubes of 1100-F commercially pure aluminium. One initial and four subsequent yield loci are established to a maximum prestrain level of 14 per cent tensile plastic strain.

The results are analysed in terms of a proposed, rationally based, yield criterion constructed according to statistical reasoning.

It is shown that during prestrain a significant degree of geometrical distortion is undergone by the yield loci, accompanied by a strong Bauschinger effect and a flattening of part of the locus opposite to the loading point.

It is found that the yield locus does not rotate during prestrain and, contrary to the case for torsion prestrain, exhibits evidence of a sharply rounded corner developing at the loading point.

The proposed criterion is shown to fit the experimental results extremely well and the mechanism of distortion is explained in terms of a statistical model for work-hardening materials.

Effect of torsional prestrain on the yield locus of 1100-F aluminium

A series of combined stress tests in torsion-tension space is carried out on thin-walled tubes of 1100-F commercially pure aluminium, prestrained to a maximum level of 10 per cent torsional plastic strain. The results are analysed in terms of a proposed, rationally based, yield criterion constructed on statistical reasoning. It is shown that during prestrain, the yield loci undergo a significant degree of distortion, accompanied by a flattening of part of the locus opposite to the loading point.

It is found that the yield locus does not rotate under prestrain and, contrary to the findings for tensile prestrain, little evidence of the development of corners at the loading point is observed. The proposed criterion is shown to provide a good fit to the experimental results.

Energy- and momentum-resolved exchange and spin-orbit interaction in cobalt film by spin-polarized two-electron spectroscopy

Spontaneous ordering of electronic spins in ferromagnetic materials is one of the best known and most studied examples of quantum correlations. Exchange correlations are responsible for long range spin order and the spin-orbit interaction (SOI) can create preferred crystalline directions for the spins, i.e., magnetic anisotropy. Presented experimental data illustrate how novel spin-polarized two-electron spectroscopy in-reflection mode allows observation of the localization of spin-dependent interactions in energy-momentum space. Comparison of spin-orbit asymmetries in spectra of Co film and clean W(110) may indicate the presence of interface specific proximity effects providing important clues to the formation of preferred orientations for the magnetic moment of the Co film. These results may help to understand the microscopic origin of interface magnetic anisotropy.

Threshold electron-impact ionization mechanism for hydrogen atoms

The near-threshold evolution of electron-impact ionization of hydrogen is revealed with measurements of the angular and energy correlations of the outgoing electrons down to 0.05 eV. The single-, double-, and triple-differential cross sections in the perpendicular plane are measured simultaneously using a dual wedge-and-strip detector on a single-toroidal energy analyzer, avoiding many experimental problems. The experimental and calculated data are in excellent agreement, within the experimental precision of +/-10%, and provide further evidence that the accurate solution of the Schrödinger equation provides a complete description of the reaction dynamics of near-threshold ionization.

Pharmacology of ivermectin

Ivermectin is a semi-synthetic macrocyclic lactone (Fig. I) active in single low doses against many parasites - particularly nematodes and arthropods. It has been registered for animal health use since early 1985, and was earlier this year approved for human use by the French Directorate o f Pharmacy and Drugs. Of particular interest is ivermectin's potential as a micro filaricide for treatment o f onchocerciasis. Clinical trials leave little doubt about the potential o f ivermectin as a therapeutic tool for symptomatic relief from the effects o f infection with Onchocerca volvulus, and the drug is also recognized to have potential in reducing transmission o f the parasite. The manufacturers (Merck, Sharp and Dohme) recently arranged to provide the drug free o f charge to the WHO for mass trials against onchocerciasis in 12 African and Central American countries. In this article we focus on the pharmacological properties o f ivermectin, with a brief consideration of its absorption, fate, excretion and side-effects, and a discussion o f its micro filaricidal action.

Electron exchange in dissociative excitation of molecular hydrogen using polarized electrons

The effects of electron exchange and spin orbit interaction in dissociative excitation processes in H2 molecules have been explored using excitation by polarized electrons. Observations of the circular and linear Stokes polarizations of the Balmer-alpha photons determined the alignment and orientation of the excited atomic hydrogen atoms, the excited molecular states, and the dissociative excitation processes via predissociation with short and long range transitions.

E1A-Based Determinants of Oncogenicity in Human Adenovirus Groups A and C

A broad spectrum of genetic and molecular investigations carried out with group C, Ad2 and Ad5, and with group A, Ad12, have shown that early region1 (E1) gene products are sufficient for complete transformation of rodent cells in vitro by these viruses. During the past quarter century, the processes by which E1A proteins, in cooperation with E1B proteins, perturb the cell cycle and induce the transformed phenotype, have become well defined. Somewhat less understood is the basis for the differential oncogenicity of these two groups of viruses, and the processes by which the E1A proteins of Ad12 induce a tumorigenic phenotype in transformants resulting from infection of cells in vivo and in vitro. In this chapter we review previous findings and present new evidence which demonstrates that Ad12 E1A possesses two or more independent functions enabling it to induce tumors. One of these functions lies in its capacity to repress transcription of MHC class I genes, allowing the tumor cells to avoid lysis by cytotoxic T lymphocytes. We have shown that class I repression is mediated through increased binding of repressor COUP-TF and decreased binding of NF-kB to the class I enhancer. In addition to mediating immune escape, E1A also determines the susceptibility of transformants to Natural Killer (NK) cell lysis, and in this case, also, Ad12 transformants are not susceptible. By using Ad12 mutants containing chimeric E1A Ad12-Ad5 genes, point mutations, or a specific deletion, we have shown that the unique spacer region of Ad12 E1A is an oncogenic determinant, but is not required for transformation in vitro. Given that the E1A regions responsible for class I repression are first exon encoded, we have examined a set of cell lines transformed by these altered viruses, and have found that while they display greatly reduced tumorigenicity, they maintain a wildtype capacity to repress class I transcription. Whether the spacer contributes to NK evasion remains unresolved. Lastly, we discuss the properties of the Ad2/Ad5 E1A C-terminal negative modulator of tumorigenicity, and examine the effects on transformation, tumor induction and transformant tumorigenicity, when the Ad5 negative modulator is placed by chimeric construction in Ad12 E1A.

Mass spectrometric studies of the path of carbon in photosynthesis: positional isotopic analysis of (13)C-labelled C(4) to C(7) sugar phosphates

The (EIMS) electron ionization mass spectrometric fragmentation patterns of the methoxime- and ethoxime-trimethylsilyl (TMS) derivatives of C(4) to C(7) sugars involved as phosphates in the Calvin pathway of photosynthesis in plants were analysed by gas chromatography/EIMS using specifically labelled (13)C analogs. In general, most but not all of the major ions in the mass spectra arise from single carbon-carbon bond cleavages of the straight-chain derivatives. The results confirm that GC/MS of the alkoxime-TMS derivatives is a viable method for measuring (13)C incorporations at individual carbon atoms in each of the sugar phosphates during photosynthetic experiments with (13)CO(2).

An immunoablative regimen of fludarabine and cyclophosphamide prevents fully MHC-mismatched murine marrow graft rejection independent of GVHD

The prevention of graft rejection in the setting of nonmyeloablative transplant approaches might be mediated by chemotherapy-induced host immunoablation and by the graft-promoting effects of graft-versus-host disease (GVHD). To evaluate whether host immunoablation alone might allow for alloengraftment, we developed an F1-into-parent murine marrow rejection model using host preparative regimens of lethal total body irradiation (TBI; 950 cGy), sublethal irradiation (600 cGy), or combinations of fludarabine (Flu) and cyclophosphamide (Cy). A preparative regimen selectivity index (SI) was calculated to determine whether host lymphocytes were preferentially depleted relative to myeloid cells (SI = number of host myeloid/number host T lymphoid cells remaining after preparative regimen administration). Saline-treated recipients were assigned an SI value of 1.0. Recipients of lethal TBI had reduced myeloid cells relative to T cells (SI = 0.6). In contrast, all Flu/Cy regimens preferentially depleted host T cells: recipients of Flu (100 mg/kg per day)/Cy (50 mg/kg per day) for 10 days (SI = 28.1); recipients of Flu (100 mg/kg per day)/Cy (100 mg/kg per day) for 10 days (SI = 64.1); and recipients of Flu (100 mg/kg per day)/Cy (50 mg/kg per day) for 19 or 27 days (SI = 74.6). The 10-day regimen of Flu/Cy (50 mg/kg per day) did not severely reduce host T cell numbers, nor did it prevent F1 marrow rejection (<1% chimerism, n = 14). In contrast, the 10-day regimen of Flu/Cy (100 mg/kg per day) reduced T-cell numbers below that of lethal TBI recipients and prevented F1 marrow rejection (11.4% chimerism, n = 15); donor chimerism was predominant in lymphoid cells and was stable through day 240 post-BMT. Additionally, the 19- or 27-day regimen of Flu/Cy, which most selectively depleted host T cells, also prevented F1 marrow rejection (6.3% chimerism, n = 15). These results therefore demonstrate that optimized Flu-containing, immunoablative preparative regimens can prevent fully MHC-disparate marrow rejection independent of GVHD.

Treatment of androgen-independent prostate cancer using antimicrotubule agents docetaxel and estramustine in combination: an experimental study

BACKGROUND

Estramustine in combination with other chemotherapeutic agents has demonstrated synergy in hormone-refractory prostate cancer. Docetaxel has demonstrated antineoplastic activity in a variety of chemotherapeutic-unresponsive tumors. We evaluated the effects of estramustine and docetaxel in preclinical models of prostate cancer.

METHODS

Cell viability of PC-3 and MAT-LyLu (MLL) cells were assessed 48 hr after drug treatment. For in vivo studies, each flank of five animals in six groups was injected with 1 x 10(6) MLL cells: control, estramustine, docetaxel (low- and high-dose), and low- and high-dose docetaxel with estramustine. Animals were treated on days 4 and 11, and sacrificed on day 14.

RESULTS

The IC(50) value for docetaxel was 2 nM in the PC-3 cells and 40 nM in the MLL cells. The addition of 100 nM of estramustine did not alter the IC(50) value for PC-3 cells. In the MLL cells, however, the IC(50) value was lowered to 15 nM. In vivo, low-dose docetaxel with estramustine demonstrated antineoplastic activity similar to that of high-dose docetaxel alone, suggesting additive activity between the drugs.

CONCLUSIONS

These results demonstrate that when used in combination, docetaxel and estramustine can be more effective at lower dosages than when the individual drugs are used alone.

Infection-resistant nonleachable materials for urologic devices

Bacterial colonization is the primary clinical problem faced by the surgeon and medical device innovator. Despite the absence of effective systemic treatment, medical implants and devices have been deployed with increasing success over the past five decades. Infection-resistant materials (IRMs) are a relatively recent addition to the science of implant and device development. The first IRM utilized leachable antimicrobial agents. Nonleachable technologies are being developed, some of which have the potential to make organ replacement even more successful in the future.

fas-mediated lysis of chronic lymphocytic leukaemia cells: role of type I versus type II cytokines and autologous fasL-expressing T cells

Given the known role of the fas cytolytic pathway in B-cell regulation, we evaluated whether fas-fasL interactions might induce chronic lymphocytic leukaemia (CLL) cell death. De novo CLL cells expressed a low level of surface fas, and were not lysed by fasL-bearing cells. CLL cells cultured in media containing the type I cytokines interleukin (IL)-12 or interferon (IFN)-alpha had increased fas expression, and were readily lysed by fasL-bearing cells. In contrast, the type II cytokine IL-4 did not increase CLL cell fas, and abrogated type I cytokine-induced fas up-regulation. With prolonged culture, IL-4 exposed CLL cells expressed an intermediate level of fas; however, such CLL cells were resistant to fas-mediated lysis. These results indicate that IL-4 inhibits fas-mediated killing of CLL cells at the level of both fas receptor expression and post-receptor events. Additionally, we have defined in vitro culture conditions which generate fasL-bearing T cells from CLL patients; such T cells efficiently mediated fas-based lysis of autologous fas-positive CLL cells. We therefore conclude that type I and type II cytokines differentially regulate the fas pathway in CLL cells, and that a combination of type I cytokines and fasL-expressing T cells may represent a new approach to the immunotherapy of CLL.

Bombesin-like neuropeptides in nematodes

This paper reports evidence of members of the bombesin-like peptide family in a number of nematodes, including Caenorhabditis, Panagrellus, Dirofilaria, Onchocerca, Brugia, Haemonchus, Ostertagia, Toxocara, and Ascaris. One of these (Ostertagia) secretes the bombesin-like material into its environment. Specific binding of gastrin-releasing peptide to the hypodermis consistent with the presence of receptors was demonstrated. These data suggest that this class of peptides may play an important role in nematode hypodermal physiology.

Academic health centers can bridge the gulf between medicine and public health

The authors review why the gulf between clinical medicine and public health has existed since the first schools of public health were established in 1916. They emphasize that academic health centers (AHCs) have the potential to bring together these two perspectives--as well as the health services perspective--to clarify what they offer and to find creative ways to build upon their combined strengths. The authors describe institutional approaches that can be taken to narrow the gulf, with examples from the initiatives of this type that are under way at The George Washington University Medical Center in Washington, D.C. For example, the authors state and discuss in detail that an AHC's medical, public health, and health services institutions should be physically and institutionally close; that collaboration between them requires well-structured interaction; that institutional structures are needed to ensure cooperation when internal competition is likely; and that collaboration is fostered by new opportunities and the potential for new resources. The authors conclude by stating that the future will require that the health education and prevention perspective of public health, the treatment perspective of medicine, and the financial and management perspective of health services be developed and integrated into the work of AHCs, and give examples of specific activities that would be possible with such integration.

Interaction of tissue transglutaminase with nuclear transport protein importin-alpha3

Tissue transglutaminase is a multifunctional enzyme which has been involved in the regulation of cell growth, differentiation, and apoptosis. Recently, nuclear localization of tTG has been reported indicating the potential of active nuclear transport. In this study we use the yeast two-hybrid assay and co-immunoprecipitation to show that tTG interacts with the nuclear transport protein importin-alpha3. Using electron microscopy we demonstrate that nuclear expression of tTG in a non-small cell lung cancer cell line is induced by retinoic acid (RA). These data suggest that importin-alpha3 could mediate active nuclear transport of tTG which may be important for the regulation of critical cellular processes.

Laparoscopic adrenal cyst resection

Two patients with left adrenal cysts underwent laparoscopic resection. In one case an adrenal origin of the cyst was suspected. In the other case the cyst was thought to be renal in origin. Both patients were female, ages 16 and 40 years. Operative time was 150 and 160 minutes. Blood loss was 50 and 30 mL. One patient received 14 mg of morphine and 60 mg of ketorolac. The other patient did not require any parenteral analgesics. Hospital stay was 1 day for both patients. Return to normal activity occurred at 15 and 7 days postoperatively, respectively. Histology in both cases revealed benign adrenal cysts. Our experience supports the laparoscopic approach for resection of adrenal cysts.