Tuning interfacial Dzyaloshinskii-Moriya interactions in thin amorphous ferrimagnetic alloys

Skyrmions can be stabilized in magnetic systems with broken inversion symmetry and chiral interactions, such as Dzyaloshinskii-Moriya interactions (DMI). Further, compensation of magnetic moments in ferrimagnetic materials can significantly reduce magnetic dipolar interactions, which tend to favor large skyrmions. Tuning DMI is essential to control skyrmion properties, with symmetry breaking at interfaces offering the greatest flexibility. However, in contrast to the ferromagnet case, few studies have investigated interfacial DMI in ferrimagnets. Here we present a systematic study of DMI in ferrimagnetic CoGd films by Brillouin light scattering. We demonstrate the ability to control DMI by the CoGd cap layer composition, the stack symmetry and the ferrimagnetic layer thickness. The DMI thickness dependence confirms its interfacial nature. In addition, magnetic force microscopy reveals the ability to tune DMI in a range that stabilizes sub-100 nm skyrmions at room temperature in zero field. Our work opens new paths for controlling interfacial DMI in ferrimagnets to nucleate and manipulate skyrmions.

Ultrafast optically induced spin transfer in ferromagnetic alloys

The vision of using light to manipulate electronic and spin excitations in materials on their fundamental time and length scales requires new approaches in experiment and theory to observe and understand these excitations. The ultimate speed limit for all-optical manipulation requires control schemes for which the electronic or magnetic subsystems of the materials are coherently manipulated on the time scale of the laser excitation pulse. In our work, we provide experimental evidence of such a direct, ultrafast, and coherent spin transfer between two magnetic subsystems of an alloy of Fe and Ni. Our experimental findings are fully supported by time-dependent density functional theory simulations and, hence, suggest the possibility of coherently controlling spin dynamics on subfemtosecond time scales, i.e., the birth of the research area of attomagnetism.

Discerning Inter- and Intramolecular Vibrations of Sulfur Polyaromatic Compounds

Thiophenes are an important class of molecules in fields as diverse as petrochemistry, molecular electronics, and optoelectronics. Thiophenic submolecular motifs are thought to play a role in molecular association and nanoaggregation phenomena in both pure materials and natural and synthetic mixtures. Vibrational (infrared and Raman) spectroscopy provides the means to characterize these species. In this work far-infrared photoacoustic and low-frequency Raman spectra of a series of polycyclic aromatic hydrocarbons containing sulfur have been measured and interpreted using DFT calculations based on a perturbational-variational method coupled with potential truncation. The approach and outcomes illustrate how inter- and intramolecular vibrations for thiophenic systems in single and multicomponent mixtures can be discriminated. This work offers the perspective to search the inter- and intramolecular signatures of the main submolecular motifs and heteroelements postulated as being present in the asphaltenes.

Ferromagnetic resonance measurements of (Co/Ni/Co/Pt) multilayers with perpendicular magnetic anisotropy

Multilayers of [Co/Ni(t)/Co/Pt]×8 with varying Ni thickness were investigated for possible use as a free layer in magnetic tunnel junctions and spintronics devices. The thickness t of the Ni sub-layer was varied from 0.3 nm to 0.9 nm and the resulting magnetic properties were compared with (Co/Ni) and (Co/Pt) multilayers. As determined from magnetic force microscopy, magnetometry and ferromagnetic resonance measurements, all multilayers exhibited perpendicular magnetic anisotropy. Compared with (Co/Pt) multilayers, the sample with t of 0.9 nm showed almost the same anisotropy field of μ 0 H k = 1.15 T but the damping constant was 40% lower. These characteristics make these multilayers attractive for spin torque based magnetoresistive devices with perpendicular anisotropy.

A dynamic pressure view cell for acoustic stimulation of fluids--Micro-bubble generation and fluid movement in porous media

The development and baseline operation of an acoustic view cell for observing fluids, and fluid-fluid and fluid-solid interfaces in porous media over the frequency range of 10-5000 Hz is described. This range includes the industrially relevant frequency range 500-5000 Hz that is not covered by existing devices. Pressure waveforms of arbitrary shape are generated in a 17.46 mm ID by 200 mm and 690.5 mm long glass tubes at flow rates up to 200 ml/min using a syringe pump. Peak-to-peak amplitudes exceeding 80 kPa are readily realized at frequencies from 10 to 5000 Hz in bubble free fluids when actuated with 20 Vpp as exemplified using castor oil. At resonant frequencies, peak-to-peak pressure amplitudes exceeding 500 kPa were obtained (castor oil at 2100 Hz when actuated with 20 Vpp). Impacts of vibration on macroscopic liquid-liquid and liquid-vapour interfaces and interface movement are illustrated. Pressure wave transmission and attenuation in a fluid saturated porous medium, randomly packed 250-330 μm spherical silica beads, is also demonstrated. Attenuation differences and frequency shifts in resonant peaks are used to detect the presence and generation of dispersed micro-bubbles (<180 μm diameter), and bubbles within porous media that are not readily visualized. Envisioned applications include assessment of the impacts of vibration on reaction, mass transfer, and flow/flow pattern outcomes. This knowledge will inform laboratory and pilot scale process studies, where nuisance vibrations may affect the interpretation of process outcomes, and large scale or in situ processes in aquifers or hydrocarbon reservoirs where imposed vibration may be deployed to improve aspects of process performance. Future work will include miscible interface observation and quantitative measurements in the bulk and in porous media where the roles of micro-bubbles comprise subjects of special interest.

Non-intrusive, high-resolution, real-time, two-dimensional imaging of multiphase materials using acoustic array sensors

Two parallel multi-element ultrasonic acoustic arrays combined with sets of focal laws for acoustic signal generation and a classical tomographic inversion algorithm are used to generate real-time two-dimensional micro seismic acoustic images of multiphase materials. Proof of concept and calibration measurements were performed for single phase and two phase liquids, uniform polyvinyl chloride (PVC) plates, and aluminum cylinders imbedded in PVC plates. Measurement artefacts, arising from the limited range of viewing angles, and the compromise between data acquisition rate and image quality are discussed. The angle range of scanning and the image resolution were varied, and the effects on the quality of the reproduction of the speed of sound profiles of model solids and liquids with known geometries and compositions were analysed in detail. The best image quality results were obtained for a scanning angle range of [-35°, 35°] at a step size of 2.5° post processed to generate images on a 40 μm square grid. The data acquisition time for high quality images with a 30 mm × 40 mm view field is 10 min. Representation of two-phase solids with large differences in speed of sound between phases and where one phase is dispersed in the form of macroscopic objects (greater than 1 mm in diameter) proved to be the most difficult to image accurately. Liquid-liquid and liquid-vapor phase boundaries, in micro porous solids by contrast, were more readily defined. Displacement of air by water and water by heptane in natural porous limestone provides illustrative kinetic examples. Measurement results with these realistic cases demonstrate the feasibility of the technique to monitor in real time and on the micrometer length scale local composition and flow of organic liquids in inorganic porous media, one of many envisioned engineering applications. Improvement of data acquisition rate is an area for future collaborative study.

Phase behaviour and phase separation kinetics measurement using acoustic arrays

Speed of sound and acoustic wave attenuation are sensitive to fluid phase composition and to the presence of liquid-liquid interfaces. In this work, the use of an acoustic array comprising 64 elements as a non-intrusive sensor for liquid-liquid interface, phase separation kinetics measurement in bulk fluids, and local composition measurement in porous media is illustrated. Three benchmark examples: the phase behaviour of methanol + mixed hexanes and methanol + heptane mixtures at 25.0 °C and 1 bar, and Athabasca bitumen + heptane in a synthetic silica porous medium at 22.5 °C and 1 bar, illustrate the accuracy of liquid-liquid interface and potential research and industrial applications of the technique. Liquid-liquid interfaces can be detected independently using both speed of sound and acoustic wave attenuation measurements. The precision of the interface location measurement is 300 μm. As complete scans can be performed at a rate of 1 Hz, phase separation kinetics and diffusion of liquids within porous media are readily tracked. The technique is expected to find application where the fluids or porous media are opaque to visible light and where other imaging techniques are not readily applied, or are too costly. A current limitation is that the acoustic probes must be cooled to less than 315 K in order for them to operate.

Abstract PD03-05: A Novel Combination Therapy for Triple Negative Breast Cancer: Erlotinib and Metformin

Background: Triple negative breast cancer (TNBC) is defined by lack of expression of estrogen, progesterone and HER2 receptors and accounts for approximately 15% of breast cancer. TNBC patients have a poor prognosis and novel therapies are needed. The majority of TNBC are basal-like tumors that overexpress the epidermal growth factor receptor (EGFR). However, clinical use of EGFR inhibitors has yielded disappointing results likely due, in part, to downstream driving mutations including PTEN. TNBC occurs more frequently in type II diabetic patients indicating that aberrations in glucose metabolism may contribute to TNBC development. The type II diabetes drug metformin has been associated with a decreased incidence of breast cancer and enhanced response to chemotherapy. In this study, we explored the combined effect of erlotinib (an EGFR kinase inhibitor) and metformin on TNBC.

Results and Methods: Using the TNBC cell lines MDA-MB-468 and BT549 with known p53 mutation, PTEN mutation and EGFR expression, we observed the novel combination of metformin and erlotinib potently induced cell death in these TNBC cell lines in a 6-day proliferation assay. Using metformin or erlotinib alone at the same doses partially inhibited growth but was unable to induce cell death. In a cytotoxic clonogenic assay, erlotinib combined with metformin significantly suppressed formation of colonies compared with either drug alone, and compared with the TORC1 inhibitor rapamycin combined with erlotinib or metformin. In addition, as compared with control MCF10A cells (an immortalized nontransformed human mammary epithelial cell line), the combined treatment preferentially induced cell death in an MCF10A cell line modified with PTEN loss, expression of dominant negative p53 and increased expression of EGFR. Again, cell death was not observed when either drug was used alone. We showed through western blots that erlotinib as a single agent is very effective in down-regulating the activity of the MAPK pathway but is less effective in down-regulating the activity of the PI3K pathway. We demonstrated that metformin and erlotinib together potentiate the inhibition of AKT and downstream S6 ribosomal protein which might be one of the mechanisms contributing to the observed synergy of the drugs.

Discussion: A significant subset of TNBC expresses EGFR, has PTEN loss and mutated p53. This recurrent set of lesions possibly leads to a unique and aberrant signaling and metabolic signature that confers TNBC an advantage for survival. We demonstrated that erlotinib and metformin act synergistically to remove this survival advantage in basal breast cancer cell lines while having minimal effect on normal epithelial breast cells. This drug combination potently down-regulates both the MAPK and PI3K pathways which are often aberrantly activated in basal-like breast tumors. Our results provide a rationale for the continued assessment of combining EGFR inhibitors with metformin in the treatment of TNBC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD03-05.

Self-expanding metal stents as an alternative to surgical bypass for malignant gastric outlet obstruction

BACKGROUND

Gastroduodenal obstruction due to malignancy can be difficult to palliate. Self-expanding metal stents (SEMS) are gaining acceptance as an effective alternative to surgical bypass.

METHODS

Patients not suitable for surgical bypass, with complete gastric outlet obstruction as a result of malignancy, were offered palliation with SEMS from November 2004 to December 2008. The procedure was performed under fluoroscopic guidance and conscious sedation. Data were collected prospectively.

RESULTS

Seventy patients underwent SEMS placement (hepatobiliary and pancreatic malignancy, 44; antral gastric carcinoma, 19; other, seven). Follow-up was complete in 69 patients (99 per cent). Technical and clinical success rates were 93 and 95 per cent respectively. Median hospital stay was 2 (range 1-18) days, median survival was 1.8 (0.1-19.0) months, and 87 per cent had improved intake after SEMS placement, as determined by Gastric Outlet Obstruction Severity Score before and after stenting (P < 0.001). Complications included two episodes of minor bleeding.

CONCLUSION

The use of SEMS to alleviate complete malignant gastric outlet obstruction in patients with limited life expectancy is successful in re-establishing enteral intake in most patients, with minimal morbidity, no mortality and a short hospital stay.

Early rebleeding and death at 6 weeks in alcoholic cirrhotic patients with acute variceal bleeding treated with emergency endoscopic injection sclerotherapy

BACKGROUND

This study evaluated the incidence of rebleeding and death at 6 weeks after a first episode of acute variceal haemorrhage (AVH) treated by emergency endoscopic sclerotherapy in a large cohort of alcoholic cirrhotic patients.

METHODS

From January 1984 to December 2006, 310 alcoholic cirrhotic patients (242 men, 68 women; mean age 51.7 years) with AVH underwent 786 endoscopic variceal injection treatments (342 emergency, 444 elective) during 919 endoscopy sessions in the first 6 weeks after the first variceal bleed. Endoscopic control of initial bleeding, variceal rebleeding and survival at 6 weeks were recorded.

RESULTS

Endoscopic intervention controlled AVH in 304 of 310 patients (98.1%). Seventy-five patients (24.2%) rebled, 38 (12.3%) within 5 days and 37 (11.9%) within 6 weeks. No patient scored as Child-Pugh A died. Seventy-seven (24.8%) Child-Pugh B and C patients died, 29 (9.3%) within 5 days and 48 (15.4%) between 6 and 42 days. Mortality increased exponentially as the Child-Pugh score increased, reaching 80% when the score exceeded 13.

CONCLUSION

Despite initial control of variceal haemorrhage, 1 in 4 patients (24.2%) rebled within 6 weeks. Survival at 6 weeks was 75.2% and was influenced by the severity of liver failure, with most deaths occurring in Child-Pugh grade C patients.

402. Cryopreservation of oocytes and follicular cells of the cane toad Bufo Marinus

Amphibians are currently the most threatened of all vertebrate groups with more than 30% of all known species in decline, facing extinction or recently extinct. Cryobanking of amphibian germ cells and reproductive tissues could be used to manage threatened species and provide insurance against extinction. However, cryopreservation of fully developed amphibian oocytes and whole embryos has not been achieved due to technical problems freezing such large cellular structures. As an alternative approach, we investigated the feasibility of developing protocols for the slow-cool freezing, storage and retrieval of developmentally competent amphibian ovarian follicles containing Stage I and II oocytes which are much smaller in size than later developmental stages. Ovarian follicles from euthanased Cane Toads were incubated in cryodiluents containing either glycerol or DMSO to assess cryoprotectant toxicity and response to slow cooling freezing protocols. The fluorescent live cell stain SYBR 14 and its counter stain propidium iodide was used to score the proportion of viable follicle cells before and after cryopreservation. Cryoprotectant type, concentration and exposure time all had significant effects (P < 0.05) on the viability of follicle cells, with significant interactions between these variables. Overall, glycerol was less toxic to follicle cells than DMSO. At higher concentrations, glycerol exerted high osmotic stress on oocytes, and there was evidence that DMSO triggered apoptosis in oocytes. The most effective cryopreservation protocol for stage I and II oocyte follicles resulted in a post-thaw recovery of a mean 70% of viable follicular cells. This protocol involved cryopreservation in 15% v/v glycerol, inclusion of seeding and temperature holding periods during cryopreservation, coupled with rapid thawing in a 30°C water bath. The successful cryopreservation of intact follicles in this study indicates the potential to recover functional ovarian tissues post cryopreservation for continuation of amphibian oogenesis in vitro or in vivo.

Adaptations in cortical and trabecular bone in response to mechanical loading with and without weight bearing

Exercise that imparts rapid, high-magnitude mechanical loading is considered to be advantageous to bone health. Previous rodent studies have suggested that swimming may also be beneficial to bone. We investigated the differential effects of exercise with and without weight bearing on cortical and trabecular bone. Forty female Sprague-Dawley rats (120 days) were weight-stratified and randomized into four groups: swim control (Cs, n = 10), swim (S, n = 10), treadmill control (Ct, n = 10), and treadmill (T, n = 10). Treadmill speed was adjusted to match the average limb loading frequency used for swimming, and all training progressed to 1 hour/day, 5 days/week, for 12 weeks. Femurs and humeri were assessed for cortical morphometry by peripheral quantitative computed tomography, areal bone mineral density (BMD) by peripheral dual-energy X-ray absorptiometry, mineral content by ashing, strength by three-point bending, and trabecular volume (BV/TV) by micro-computed tomography. Swimming was associated with increases in cortical thickness and BMD in the humerus midshaft and trabecular BV/TV in the distal femur and proximal humerus compared with age-matched controls. Compared to swimming, treadmill training was associated with increases in percent ash of the femur and humerus and Young's modulus of the femur. Swimming appears to engender novel bone strains and osteogenic adaptations in the humerus and femur, which are different from those induced by normal cage activity. In summary, our findings suggest that when limb loading frequency is matched, swimming may afford greater benefits to cortical and trabecular bone than uphill treadmill work in rats.

Hydatid disease of the liver

Echinococcus granulosus remains a clinical problem in sheep and subsistence farming communities in South Africa. The most commonly affected organs are the liver and the lung. Most cysts remain clinically silent and are diagnosed incidentally or when complications occur. Clinical examination is unreliable in making the diagnosis. Serological testing has a broad range of sensitivity and specificity and is dependent on the purity of the antigens utilised. Ultrasound examination of the abdomen is gens utilised. Ultrasound examination of the abdomen is both sensitive and cost effective. Computed tomography and endoscopic retrograde cholangiopancreatography (ERCP) are reserved for complicated cases. The differential diagnosis includes any cystic lesion of the liver. Liver hydatid cysts can be treated by medical or minimally invasive (laparoscopic and percutaneous) means or by conventional open surgery. The most effective chemotherapeutic agents against the parasite are the benzimidazole carbamates, albendazole and mebendazole. Albendazole is more efficacious, but recommended treatment regimens differ widely in terms of timing, length of treatment and dose. Medical treatment alone is not an effective and durable treatment option. PAIR (puncture, aspiration, injection, reaspiration) is the newest and most widely practised minimally invasive technique with encouraging results, but it requires considerable expertise. Open surgery remains the most accessible and widely practised method of treatment in South Africa. The options are either radical (pericystectomy and hepatic resection) or conservative (deroofing and management of the residual cavity). Various scolicidal agents are used intraoperatively (Eusol, hypertonic saline and others), although none have been tested in a formal randomised controlled trial. Laparoscopic surgery trials are small and unconvincing at present and should be limited to centres with expertise. Complicated cysts (intrabiliary rupture and secondary infection) may require ERCP to obtain biliary clearance before surgery, and referral to a specialist centre may be indicated.

The Evolving Role of Endoscopic Treatment for Bleeding Esophageal Varices

The treatment of acute and recurrent variceal bleeding is best accomplished by a skilled, knowledgeable, and well-equipped team using a multidisciplinary integrated approach. Optimal management should provide the full spectrum of treatment options including pharmacologic therapy, endoscopic treatment, interventional radiologic procedures, surgical shunts, and liver transplantation. Endoscopic therapy with either band ligation or injection sclerotherapy is an integral component of the management of acute variceal bleeding and of the long-term treatment of patients after a variceal bleed. Variceal eradication with endoscopic ligation requires fewer endoscopic treatment sessions and causes substantially less esophageal complications than does injection sclerotherapy. Although the incidence of early gastrointestinal rebleeding is reduced by endoscopic ligation in most studies, there is no overall survival benefit relative to injection sclerotherapy. Simultaneous combined ligation and sclerotherapy confers no advantage over ligation alone. A sequential staged approach with initial endoscopic ligation followed by sclerotherapy when varices are small may prove to be the optimal method of reducing variceal recurrence. Overall, current data demonstrate clear advantages for using ligation in preference to sclerotherapy. Ligation should therefore be considered the endoscopic treatment of choice in the treatment of esophageal varices.

Preclinical evaluation of a prostate-targeted gene-directed enzyme prodrug therapy delivered by ovine atadenovirus

Gene-directed enzyme prodrug therapy (GDEPT) based on the Escherichia coli enzyme, purine nucleoside phosphorylase (PNP), provides a novel strategy for treating slowly growing tumors like prostate cancer (CaP). PNP converts systemically administered prodrug, fludarabine phosphate, to a toxic metabolite, 2-fluoroadenine, that kills PNP-expressing and nearby cells by inhibiting DNA, RNA and protein synthesis. Reporter gene expression directed by a hybrid prostate-directed promoter and enhancer, PSMEPb, was assayed after plasmid transfection or viral transduction of prostate and non-CaP cell lines. Androgen-sensitive (AS) LNCaP-LN3 and androgen-independent (AI) PC3 human CaP xenografts in nude mice were injected intratumorally with an ovine atadenovirus vector, OAdV623, that carries the PNP gene under PSMEPb, formulated with cationic lipid for enhanced infectivity. Fludarabine phosphate was then given intraperitoneally for 5 days at 75 mg/m2/day. PNP expression was evaluated by enzymic conversion of its substrate using reverse phase HPLC. OAdV623 showed excellent in vitro transcriptional specificity for CaP cells. In vivo, expression of PNP persisted for > 6 days after OAdV623 injection and a single treatment provided 100% increase in tumor doubling time and > 50% inhibition of tumor growth for both LNCaP-LN3 and PC3 lines, with increased tumor necrosis and apoptosis and decreased tumor cell proliferation. OAdV623 significantly suppressed the growth of AS and AI human CaP xenografts in mice.

Diagnostic laparoscopy and diverting sigmoid loop colostomy in the management of civilian extraperitoneal rectal gunshot injuries

Background

This prospective study reviews the management of isolated civilian extraperitoneal rectal gunshot injuries using a protocol of diagnostic laparoscopy and abdominal wall trephine diverting loop colostomy, without laparotomy, distal rectal washout and presacral drainage.

Methods

Patients admitted to the trauma unit at Groote Schuur Hospital between January 2000 and December 2002 with a rectal injury were evaluated. A rectal injury was confirmed by digital rectal examination and proctosigmoidoscopy. Missile peritoneal violation was excluded by diagnostic laparoscopy. Normal laparoscopy was followed by creation of a diverting sigmoid loop colostomy through an abdominal wall trephine, without a laparotomy. No distal rectal washout or presacral drainage was performed.

Results

Of the 104 patients admitted with 106 rectal injuries, 20 (19·2 per cent) qualified for inclusion in the study. All had sustained low-velocity gunshot injuries of which 18 exhibited a transpelvic trajectory. Diagnostic laparoscopy was normal and a trephine diverting loop sigmoid colostomy was performed in all 20 patients. No pelvic sepsis occurred. Two patients developed rectocutaneous fistulas, both of which resolved without surgical treatment. Nineteen stomas have since been closed.

Conclusion

Low-velocity gunshot injuries isolated to the extraperitoneal rectum can be managed safely by laparoscopic exclusion of intraperitoneal missile penetration and diverting sigmoid loop colostomy, without laparotomy, distal rectal washout or presacral drainage

Influence of hormone environment and donor age on cryopreserved common wombat (Vombatus ursinus) ovarian tissue xenografted into nude mice

Developmentally competent oocytes can be collected from xenografted ovarian tissues; however, optimal xenograft conditions need to be established for this technique to be of use in assisted reproduction. In the present study, common wombat ovarian tissue was xenografted under the kidney capsule of nude mice to clarify the role of recipient gonadal status and donor tissue age on graft establishment, follicle development and oocyte recovery. Eighty-nine per cent of all grafts were recovered; of these, 78% contained growing follicles. In female graft recipients, follicle development to the antral stage occurred earlier in ovariectomised recipients compared with intact graft recipients. Similarly, follicle development occurred earlier in recipients of pouch young ovarian tissue grafts when compared with subadult xenografts. Follicle development proceeded to the antral stage in subadult grafts placed under the kidney capsule of male recipient mice, albeit at a slower rate than subadult grafts placed in female recipients. Oocytes were collected from grafts placed in female and male recipients, but no mature oocytes were observed at the time of collection, nor could these oocytes be matured in vitro. The present study demonstrated that common wombat pouch young tissue xenografted to female recipient mice, and subadult ovarian tissue xenografted to male recipient mice, can develop to the antral stage and can therefore facilitate oocyte collection. However, mature oocytes were not obtained using the current protocol.

Terminology associated with vitrification and other cryopreservation procedures for oocytes and embryos

Over the past 30 years many cryopreservation procedures have been applied to oocytes, embryos, sperm, ovarian and testicular tissue. Over this time many, often specialized, terms have been developed for all aspects of these procedures. This can make it difficult for readers who are not familiar with the terminology or protocols to compare and evaluate different procedures. This paper describes the main cryopreservation procedures, the terminology associated with them, and briefly explains the underlying physical, chemical and biological processes. The aim is to help readers understand and interpret other papers on slow cooling, rapid cooling, ultrarapid cooling and vitrification.

Comparison of slow- and rapid-cooling protocols for early-cleavage-stage Macaca fascicularis embryos

Cryostorage of nonhuman primate embryos by time-consuming slow-cooling methods is often limited to early cleavage stages. Effective rapid-cooling methods have been developed for many species and represent valuable tools for laboratory- and field-based studies of nonhuman primate reproductive biology. However, few rapid-cooling protocols have been applied to nonhuman primate embryos in terms of comparing various developmental stages. Here we compare slow cooling vs. two- and three-step rapid cooling of two-, four-, and eight-cell Macaca fascicularis (Mf) embryos. Rapid cooling was conducted in open pulled straws (OPS) using cooling solutions containing reduced quantities of ethylene glycol (EG) and supplemented with either of two high-molecular-weight polymers, ficoll and dextran. The survival of the slow-cooled embryos, but not the rapid-cooled embryos, was independent of embryonic stage at cryostorage. Slow cooling was associated with greater cell survival (82%) post thaw compared to warming following rapid cooling (18-29%). Slow cooling resulted in a high proportion of embryo survival (18/20; 90%) and cleavage (15/18; 83%) post thaw. Rapid cooling resulted in significantly reduced percentages of embryo survival (26-32%) and embryo cleavage in culture (29-38%) after warming. Conventional slow cooling was more effective than the rapid-cooling protocols employed in this study for cryopreservation of early-cleavage-stage Mf embryos.

Structure and expression of the follicle-stimulating hormone receptor gene in a marsupial, Macropus eugenii

Follicle stimulating hormone (FSH) is essential for folliculogenesis. The function of FSH is mediated through its receptor (FSHr) and modulation of the receptor is thought to be the mechanism by which the responsiveness of follicles to gonadotrophins is regulated. FSHr is alternatively spliced to produce several transcripts in all eutherian species studied. However, controversy exists over the significance of alternatively spliced transcripts. In this study, we cloned and characterised the tammar wallaby (Macropus eugenii) FSHr gene and examined its expression. Comparison of gene structure and function between marsupials and eutherians enables identification of conserved features that are likely to be of functional significance. Tammar FSHr shares 94% amino acid similarity with human FSHr and is expressed in both the adult testis and ovary suggesting a similar function for this gene in both marsupials and eutherians. Tammar FSHr undergoes alternate splicing to produce four transcripts consistent with the splice variants seen in eutherians. These results strongly suggest that alternate splicing is of functional significance in the ovary since it has remained a highly conserved character of this gene for over 100 million years of divergent evolution.

Xenografting of canine ovarian tissue to ovariectomized severe combined immunodeficient (SCID) mice

Xenografting of ovarian tissue salvaged from valuable dogs to an immunologically incompetent recipient is a possible mechanism to allow the ovarian tissue to be used for recovery of fertilizable oocytes. In this study, follicular development was assessed after xenotransplantation of fresh canine ovarian tissue into immunodeficient mice. Fresh prepubertal canine ovarian tissue was grafted beneath the kidney capsule of 7-week-old ovariectomized severe combined immunodeficient mice. At intervals after grafting, the recipient mice were killed, necropsied and the xenografts were recovered. The number and stage of development of follicles were assessed quantitatively by histological examination of serial sections of the xenografts. By day 56 after grafting, recruitment of primordial follicles had occurred but follicular development to the antral stage was not observed. The recipients showed persistent vaginal cornification and uterine dilation, which indicates that the grafts were producing hormones. However, these changes are not consistent with the oestrous cycle of either bitches or mice, indicating that inappropriate communication may occur between the recipient hypothalamic-pituitary glands and the axis of the xenograft gonad.

Experimental models for ovarian tissue and immature follicles

Primordial and growing follicles are abundant within the ovaries of healthy young female mammals. While our understanding of follicular dynamics is based mainly on studies of normal ovaries in intact animals, techniques such as ovarian grafting and in vitro culture, in particular when used in combination with cryopreservation, have provided both significant additional insights and a source of mature oocytes. Primordial follicles are small, quiescent, and most commonly located within the collagen-rich outer portion of the ovary. Providing that appropriate collection, handling, freezing, and thawing methods are used, they can tolerate cryopreservation very well irrespective of whether they are frozen within a whole ovary (small species), as ovarian pieces, or as individual, isolated, follicles. Animal studies show that grafts of such fresh or frozen materials can, providing that they contain viable follicles, form mature fertilizable oocytes, produce hormones, and support pregnancies to term. Grafts can be returned to the original donor (autograft), but grafting between histocompatible individuals of the same species and between species (xenografts) is also possible. Cryopreservation and grafting are therefore useful both as practical and as experimental tools. Clinically, ovarian tissue has started to be collected and frozen for patients who are at risk of ovarian failure. Very recent case reports show that such frozen ovarian tissue autografts can support the return of menses and antral follicle formation in patients, although as yet no pregnancies have been established.

Influence of donor age on development of gonadal tissue from pouch young of the tammar wallaby, Macropus eugenii, after cryopreservation and xenografting into mice

Ovaries from a marsupial, the tammar wallaby (Macropus eugenii), were grafted into a eutherian recipient at known stages of development to ascertain whether normal development would occur. Xenografted ovaries from pouch young < 20 days old, before the onset of meiosis, retained few germ cells and developed tubule-like structures reminiscent of seminiferous cords. Ovaries from 50-day-old pouch young, which contain primordial follicles, developed into antral follicles and corpora lutea within the eutherian host, and produced hormones that stimulated the reproductive tract of the host. The timing of onset of antrum formation and the progress of follicle development were advanced relative to the timing of events in ovaries in situ. Frozen-thawed ovaries from 50-day-old donors developed into preantral follicles, but at a reduced rate and number. This finding shows that gonads of a marsupial species can develop as xenografts in a eutherian, forming large antral follicles. Accelerated follicular development in xenografts provides a potentially valuable model for studying the factors that control follicle development. Assisted reproduction of endangered marsupials may also be feasible using follicles from pouch young grown as xenografts in a eutherian host.

Bone mineral density of competitive male mountain and road cyclists

The purpose of this study was to compare the bone mineral density (BMD) of two types of trained male cyclists (n = 30) with recreationally active men (n = 15), aged 20-40 years. Sixteen of the cyclists regularly trained for, and competed in, cross-country mountain bike races. The other 14 cyclists trained and raced on the road. The cyclists had trained an average of 11 +/- 3 hours per week for 8 +/- 4 years. Fifteen recreationally active men volunteered as controls. Dual-energy X-ray absorptiometry (DXA) was used to assess BMD of the proximal femur, lumbar spine, and total body. Anthropometric, muscle strength and power, aerobic fitness, and sex hormone data assessments were conducted on all participants. Mountain cyclists were younger and weighed less than road cyclists and controls. BMD at all sites was comparable among the three groups (p > 0.05). When adjusted for body weight and controlled for age, BMD was significantly higher at all sites in the mountain cyclists compared with the road cyclists and controls. Some anthropometric, physical fitness, and sex steroid variables were predictive of BMD, but of these variables, only total body weight, total body fat, and aerobic fitness were different between the groups. In conclusion, endurance road cycling does not appear to be any more beneficial to bone health than recreational activity in apparently healthy men of normal bone mass. Higher BMD in the mountain cyclists suggests that mountain cycling may provide an osteogenic stimulus that is not inherent to road cycling.

Characterization of four CD18 mutants in leucocyte adhesion deficient (LAD) patients with differential capacities to support expression and function of the CD11/CD18 integrins LFA-1, Mac-1 and p150,95

Leucocyte adhesion deficiency (LAD) is a hereditary disorder caused by mutations in the CD18 (beta2 integrin) gene. Four missense mutations have been identified in three patients. CD18(A270V) supports, at a diminished level, CD11b/CD18 (Mac-1, alphaMbeta2 integrin) and CD11c/CD18 (p150,95, alphaXbeta2 integrin) expression and function but not CD11a/CD18 (LFA-1, alphaLbeta2 integrin) expression. Conversely, CD18(A341P) supports a limited level of expression and function of CD11a/CD18, but not of the other two CD11/CD18 antigens. CD18(C590R) and CD18(R593C) show a decreasing capacity to associate with the CD11a, CD11c and CD11b subunits. Transfectants expressing the CD11a/CD18 with the C590R and R593C mutations are more adhesive than transfectants expressing wild-type LFA-1, and express the reporter epitope of the monoclonal antibody 24 constitutively. Thus, the four mutations affect CD18 differently in its capacities to support CD11/CD18 expression and adhesion. These results not only provide a biochemical account for the clinical diversity of patients with leucocyte adhesion deficiency, but also offer novel insights into the structural basis of interaction between the alpha and beta subunits, which is an integral component in our understanding of integrin-mediated adhesion and its regulation.

Swim-trained rats have greater bone mass, density, strength, and dynamics

Weight-bearing exercise is traditionally recommended for improving bone health in postmenopausal women. Effects of swim exercise were studied as an alternative to weight-bearing exercise in ovariectomized rats. Rats in a swim group (Sw, n = 8) swam for 12 wk, 5 days/wk for 60 min per session. A control group (Con, n = 9) engaged in no structured exercise. Femurs were analyzed for bone mineral density and for bone mineral content by dual energy X-ray absorptiometry, biomechanical properties by three-point bending (Instron), and bone structure and formation by histomorphometry. Food intake did not differ among groups. Final body weights were significantly lower in Sw compared with Con (P < 0.05). Swimmers had significantly greater femoral shaft bone mineral density and content (P < 0.05) compared with Con. Femurs of the Sw group had greater mechanical properties (P < 0.05) compared with Con. Histomorphometric data were significantly better in the Sw group compared with Con after the 12-wk intervention (P < 0.05). In conclusion, data from this study demonstrate some beneficial effects of swim exercise on bone structure, turnover, and strength.

The N-terminal region and the mid-region complex of the integrin beta 2 subunit

In the primary sequence of the integrin beta subunit, the N-terminal region (NTR) and mid-region are separated by the I-like domain. To determine the spatial relationship and functional properties of the integrin beta(2) NTR and mid-region, we constructed beta(2)/beta(7) chimeras in which the NTR, I-like domain, and the mid-region of the beta(2) subunit were replaced by those of beta(7). Changing either the beta(2) NTR or mid-region, but not the I-like domain to that of beta(7) did not affect LFA-1 (alpha(L)beta(2)) formation and surface expression. Thus, the specificity of alpha(L)beta(2) pairing is conferred by the I-like domain but not the NTR or mid-region. Using these chimeras, the epitopes of six anti-beta(2) mAbs (H52, 7E4, AZN-L18, AZN-L27, KIM202, and MEM-148) were mapped. All except H52 require both the NTR and mid-region for epitope expression. Since these mAbs have distinct properties in terms of epitope expression and effect on LFA-1 binding to ICAM-1, we conclude that the beta(2) NTR and mid-region interact extensively. Although the I-like domain is located between the NTR and mid-region, its removal does not affect the folding of the beta(2) NTR/mid-region complex because this complex alone can be expressed as a soluble protein and precipitated by the appropriate mAbs. Finally, the mAbs H52 and 7E4, abrogated KIM185- but not Mg/EGTAinduced LFA-1/ICAM-1 binding and the epitope of MEM-148 is expressed on Mg/EGTA-activated but not resting LFA-1. These results suggest that the NTR/mid-region complex is involved in the regulation of LFA-1 function.

Defining the repeating elements in the cysteine-rich region (CRR) of the CD18 integrin beta 2 subunit

The cysteine-rich region (CRR) of the integrin beta subunits is organised into four repeating elements. By expression of a panel of truncated beta 2 subunits, and CRR segments fused to the C-terminal end of a CD4 soluble fragment, the segment required for the expression of two monoclonal antibody conformational epitopes was determined. This segment, E482-Q574, contains 16 cysteines representing two repeating units. We have thus defined the CRR unit motif of 'xC---C---C---CxCxxCxC---Cx', where 'x' represents a single residue, and '---' represents a stretch of four to 14 residues.

The GTPase effector domain sequence of the Dnm1p GTPase regulates self-assembly and controls a rate-limiting step in mitochondrial fission

Dnm1p belongs to a family of dynamin-related GTPases required to remodel different cellular membranes. In budding yeast, Dnm1p-containing complexes assemble on the cytoplasmic surface of the outer mitochondrial membrane at sites where mitochondrial tubules divide. Our previous genetic studies suggested that Dnm1p's GTPase activity was required for mitochondrial fission and that Dnm1p interacted with itself. In this study, we show that bacterially expressed Dnm1p can bind and hydrolyze GTP in vitro. Coimmunoprecipitation studies and yeast two-hybrid analysis suggest that Dnm1p oligomerizes in vivo. With the use of the yeast two-hybrid system, we show that this Dnm1p oligomerization is mediated, in part, by a C-terminal sequence related to the GTPase effector domain (GED) in dynamin. The Dnm1p interactions characterized here are similar to those reported for dynamin and dynamin-related proteins that form higher order structures in vivo, suggesting that Dnm1p assembles to form rings or collars that surround mitochondrial tubules. Based on previous findings, a K705A mutation in the Dnm1p GED is predicted to interfere with GTP hydrolysis, stabilize active Dnm1p-GTP, and stimulate a rate-limiting step in fission. Here we show that expression of the Dnm1 K705A protein in yeast enhances mitochondrial fission. Our results provide evidence that the GED region of a dynamin-related protein modulates a rate-limiting step in membrane fission.

Studies on replacing most of the penetrating cryoprotectant by polymers for embryo cryopreservation

Solutions used for vitrification or rapid cooling of embryos usually contain high concentrations of penetrating cryoprotectants. At these concentrations embryos can tolerate the penetrating cryoprotectants for only short periods of time without damage. This study designed and tested cryoprotectant solutions that combined high polymer concentrations with low penetrating cryoprotectant concentrations. Mouse 2-cell embryo development was not compromised by up to 15-min exposure to 30 wt% solutions of the polymers Ficoll 70,000 MW or dextran 69,000 MW at room temperature. However, our batches of polyvinylpyrrolidone (PVP) 10,000 and PVP 40,000 were embryo-toxic even after extensive dialysis against Milli-Q water. As both Ficoll and dextran contribute to a solution's physical vitrification properties, we formulated vitrifying solutions containing only 11 to 27 wt% ethylene glycol (EG) by including 34 to 49 wt% polymers (27 wt% EG + 34 wt% Ficoll, 27 wt% EG + 34 wt% dextran, 16 wt% EG + 39 wt% Ficoll, or 11 wt% EG + 49 wt% Ficoll, in phosphate-buffered saline (PBS)). Novel solutions were designed for 0.25 ml straw as a viscous matrix for encapsulation of embryos. These yielded high rates of development of 2-cell mouse embryos after rapid cooling and warming (> or = 96% expanded blastocysts in vitro and > or = 62% viable fetuses as assessed on day 15 of gestation in vivo) in all tested solutions. All control 2-cell embryos formed expanded blastocysts in vitro and 78% formed fetuses in vivo. Comparable results were obtained with both 4-cell and 8- to 16-cell mouse embryos. The lower toxicity of Ficoll and dextran may explain why these new solutions gave better results than had previously been reported for solutions containing 7.5% PVP and low concentrations of EG (2 M).

Yeast vectors for integration at the HO locus

We have constructed new yeast vectors for targeted integration of desired sequences at the Saccharomyces cerevisiae HO locus. Insertion at HO has been shown to have no effect on yeast growth, and thus these integrations should be neutral. One vector contains the KanMX selectable marker, and integrants can be selected by resistance to G418. The other vector contains the hisG-URA3-hisG cassette, and integrants can be selected by uracil prototrophy. Subsequent growth on 5-FOA permits identification of colonies where recombination between the hisG tandem repeats has led to loss of the URA3 marker and return to uracil auxotrophy. We also describe several new bacterial polylinker vectors derived from pUC21 (ampicillin resistance) and pUK21 (kanamycin resistance).

Body composition and physical self-concept in older women

We sought to determine the performance and anthropometric correlates of physical self-concept and self-esteem and to observe whether long-term resistance training would alter these variables in postmenopausal women. Forty-four nonsmoking, community-dwelling, Caucasian women aged 50-75 years participated in the study. Half of the subjects participated in a 9-month regimen of weight-bearing exercises performed 3 times per week which emphasized lower body muscle strength and power development. At baseline, total body fat was negatively associated with physical self-concept and perception of physical appearance but not with self-esteem. Perception of physical appearance improved in both exercisers and controls after the 9-month trial but was most noticeable in exercisers who had low self-esteem at baseline. The only predictor of improvement in perception of physical appearance was a decrease in lower body fat mass. Minimal or nonsignificant change in psychological measures associated with the training may be due to high initial values.

Follicular development in cryopreserved Common Wombat ovarian tissue xenografted to Nude rats

The Northern Hairy-nosed Wombat (Lasiorhinus krefftii) is a highly endangered marsupial species and every possible option for sustaining the species needs to be explored. One important approach may be the development of assisted reproductive technologies in the non-endangered Common Wombat (Vombatus ursinus) and Southern Hairy-nosed Wombat (Lasiorhinus latifrons) for application in breeding the Northern Hairy-nosed Wombat. In this study, it was examined whether cryopreserved Wombat ovarian tissue would develop following xenografting to immunologically deficient rats. Ovarian tissue was collected from Common Wombats (n = 3) and cryopreserved as small cortical pieces. After thawing the cortical pieces were grafted underneath the kidney capsule of Nude rats (n = 16). The grafts were recovered at 2, 4, and 10 weeks after transplantation and their gross and histological appearance investigated. Two weeks after grafting (n = 2), the tissue was revascularized and healthy primordial follicles were present. At week 4 (n = 2), some follicular development was present. At week 10, six rats received human chorionic gonadotrophin (hCG) to trigger follicle and oocyte maturation while another six rats were not given any treatment. The administration of hCG did not induce preovulatory follicles and oocyte maturation although type 5 follicles were present in ovarian tissue collected 10 weeks posttransplantation in both treated and untreated groups. This study demonstrates for the first time that Wombat ovarian tissue can survive and function when grafted into immunocompromized rats and that Wombat ovarian follicles can be recruited to growth and development in an ovarian xenograft. This model system has the potential to produce mature oocytes from endangered species for use in assisted reproductive technologies such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), and mature oocytes from non-endangered species for nuclear transfer which may be necessary for the preservation of critically endangered species.

A strategy for rapid cooling of mouse embryos within a double straw to eliminate the risk of contamination during storage in liquid nitrogen

Double packaging, in which an inner straw containing the specimen is inserted into an outer, larger straw (here termed 'straw-in-straw') to prevent the inner straw from coming into direct contact with liquid nitrogen provides a simple strategy for reducing or eliminating the potential contamination risk associated with storage in liquid nitrogen. This approach has in the past been used in conjunction with cryopreservation by slow cooling, but has not previously been tested for use throughout an entire rapid cooling and warming procedure. This study determined whether keeping the straw containing the embryos inside a second protecting container throughout the cryopreservation and storage protocol would compromise embryo viability. We established that a cryoprotectant containing a high polymer concentration (35% dextran or Ficoll) together with 25% ethylene glycol (as the penetrating cryoprotectant) was highly effective for day 2 and day 3 mouse embryos in both single and double straws. The survival and development of all cryopreserved embryos, as assessed both in vitro and in vivo, was not statistically different to their untreated controls. This established that a protein/serum-free cryoprotectant solution supplemented with polymers could provide complete protection of mouse embryos. It also shows, for the first time, that embryos can be cooled by direct immersion in liquid nitrogen and warmed by direct immersion into a waterbath within a double straw arrangement to reduce the likelihood of contamination.

The dynamin-related GTPase, Mgm1p, is an intermembrane space protein required for maintenance of fusion competent mitochondria

Mutations in the dynamin-related GTPase, Mgm1p, have been shown to cause mitochondrial aggregation and mitochondrial DNA loss in Saccharomyces cerevisiae cells, but Mgm1p's exact role in mitochondrial maintenance is unclear. To study the primary function of MGM1, we characterized new temperature sensitive MGM1 alleles. Examination of mitochondrial morphology in mgm1 cells indicates that fragmentation of mitochondrial reticuli is the primary phenotype associated with loss of MGM1 function, with secondary aggregation of mitochondrial fragments. This mgm1 phenotype is identical to that observed in cells with a conditional mutation in FZO1, which encodes a transmembrane GTPase required for mitochondrial fusion, raising the possibility that Mgm1p is also required for fusion. Consistent with this idea, mitochondrial fusion is blocked in mgm1 cells during mating, and deletion of DNM1, which encodes a dynamin-related GTPase required for mitochondrial fission, blocks mitochondrial fragmentation in mgm1 cells. However, in contrast to fzo1 cells, deletion of DNM1 in mgm1 cells restores mitochondrial fusion during mating. This last observation indicates that despite the phenotypic similarities observed between mgm1 and fzo1 cells, MGM1 does not play a direct role in mitochondrial fusion. Although Mgm1p was recently reported to localize to the mitochondrial outer membrane, our studies indicate that Mgm1p is localized to the mitochondrial intermembrane space. Based on our localization data and Mgm1p's structural homology to dynamin, we postulate that it functions in inner membrane remodeling events. In this context, the observed mgm1 phenotypes suggest that inner and outer membrane fission is coupled and that loss of MGM1 function may stimulate Dnm1p-dependent outer membrane fission, resulting in the formation of mitochondrial fragments that are structurally incompetent for fusion.

Dnm1p GTPase-mediated mitochondrial fission is a multi-step process requiring the novel integral membrane component Fis1p

Yeast Dnm1p is a soluble, dynamin-related GTPase that assembles on the outer mitochondrial membrane at sites where organelle division occurs. Although these Dnm1p-containing complexes are thought to trigger constriction and fission, little is known about their composition and assembly, and molecules required for their membrane recruitment have not been isolated. Using a genetic approach, we identified two new genes in the fission pathway, FIS1 and FIS2. FIS1 encodes a novel, outer mitochondrial membrane protein with its amino terminus exposed to the cytoplasm. Fis1p is the first integral membrane protein shown to participate in a eukaryotic membrane fission event. In a related study (Tieu, Q., and J. Nunnari. 2000. J. Cell Biol. 151:353-365), it was shown that the FIS2 gene product (called Mdv1p) colocalizes with Dnm1p on mitochondria. Genetic and morphological evidence indicate that Fis1p, but not Mdv1p, function is required for the proper assembly and distribution of Dnm1p-containing fission complexes on mitochondrial tubules. We propose that mitochondrial fission in yeast is a multi-step process, and that membrane-bound Fis1p is required for the proper assembly, membrane distribution, and function of Dnm1p-containing complexes during fission.

Suppressors of mdm20 in yeast identify new alleles of ACT1 and TPM1 predicted to enhance actin-tropomyosin interactions

The actin cytoskeleton is required for many aspects of cell division in yeast, including mitochondrial partitioning into growing buds (mitochondrial inheritance). Yeast cells lacking MDM20 function display defects in both mitochondrial inheritance and actin organization, specifically, a lack of visible actin cables and enhanced sensitivity to Latrunculin A. mdm20 mutants also exhibit a temperature-sensitive growth phenotype, which we exploited to isolate second-site suppressor mutations. Nine dominant suppressors selected in an mdm20/mdm20 background rescue temperature-sensitive growth defects and mitochondrial inheritance defects and partially restore actin cables in haploid and diploid mdm20 strains. The suppressor mutations define new alleles of ACT1 and TPM1, which encode actin and the major form of tropomyosin in yeast, respectively. The ACT1 mutations cluster in a region of the actin protein predicted to contact tropomyosin, suggesting that they stabilize actin cables by enhancing actin-tropomyosin interactions. The characteristics of the mutant ACT1 and TPM1 alleles and their potential effects on protein structure and binding are discussed.

Effect of integrin beta 2 subunit truncations on LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) assembly, surface expression, and function

LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18) are members of the beta2 integrins involved in leukocyte function during immune and inflammatory responses. We aimed to determine a minimized beta2 subunit that forms functional LFA-1 and Mac-1. Using a series of truncated beta2 variants, we showed that the subregion Q23-D300 of the beta2 subunit is sufficient to combine with the alphaL and alphaM subunits intracellularly. However, only the beta2 variants terminating after Q444 promote cell surface expression of LFA-1 and Mac-1. Thus, the major cysteine-rich region and the three highly conserved cysteine residues at positions 445, 447, and 449 of the beta2 subunit are not required for LFA-1 and Mac-1 surface expression. The surface-expressed LFA-1 variants are constitutively active with respect to ICAM-1 adhesion and these variants express the activation reporter epitope of the mAb 24. In contrast, surface-expressed Mac-1, both the wild type and variants, require 0. 5 mM MnCl2 for adhesion to denatured BSA. These results suggest that the role of the beta2 subunit in LFA-1- and Mac-1-mediated adhesion may be different.

Long-term exercise using weighted vests prevents hip bone loss in postmenopausal women

BACKGROUND

Bone mineral density (BMD) is a primary risk factor for hip fracture. We studied the effect of long-term weighted vest plus jumping exercise on hip BMD in postmenopausal women as a strategy for reducing hip fracture risk.

METHODS

Eighteen postmenopausal women (age = 64.1 +/- 1.6 years at baseline, 69.9 +/- 1.6 years at post-testing) who had participated in a 9-month exercise intervention volunteered for the long-term trial. Nine of the original group engaged in weighted vest plus jumping exercise three times per week for 32 weeks of the year over a period of 5 years. Nine of the original controls were active but not enrolled in the exercise program. BMD of the proximal femur was assessed by dual energy x-ray absorptiometry at baseline and after 5 years.

RESULTS

At baseline, groups were similar for age, weight, height, years past menopause, and BMD of the femoral neck, trochanter, and total hip. At follow-up, differences in BMD at all regions of the hip were higher in exercisers than controls. For exercisers, changes in BMD were + 1.54% +/- 2.37%, -0.24% +/- 1.02%, and -0.82% +/- 1.04% (means + SE) at the femoral neck, trochanter, and total hip, respectively; controls decreased at all sites (-4.43% +/- 0.93%. 3.43% +/- 1.09%, and -3.80% +/- 1.03%, respectively).

CONCLUSIONS

A 5-year program of weighted vest plus jumping exercise maintains hip BMD by preventing significant bone loss in older postmenopausal women. Furthermore, this particular program appears to promote long-term adherence and compliance, as evidenced by the commitment of the exercisers for more than 5 years.

A novel point mutation in CD18 causing the expression of dysfunctional CD11/CD18 leucocyte integrins in a patient with leucocyte adhesion deficiency (LAD)

Leucocyte adhesion deficiency type 1 (LAD-1) is characterized by the incapacity of leucocytes to carry out their adhesion functions via their CD11/CD18 antigens, which are also referred to as the leucocyte integrins. The patients generally suffer from poor wound healing and recurrent bacterial and fungal infections. In severe cases, the infections are often systemic and life-threatening. A LAD patient (AW) of moderate phenotype has been identified but, unlike most other cases, the level of CD11/CD18 antigens on her leucocytes are uncharacteristically high for a LAD patient. Molecular analysis revealed that she is a compound heterozygote for CD18 mutations. She has inherited a D231H mutation from her father and a G284S mutation from her mother. By transfection studies, it was established that the G284S mutation does not support CD11/CD18 antigen expression on the cell surface. In contrast, the D231H mutation does not affect CD18 forming integrin heterodimers with the CD11 antigens on the cell surface. However, the expressed integrins with the D231H mutation are not adhesive to ligands.

Gonadotrophin administration can benefit ovarian tissue grafted to the body wall: implications for human ovarian grafting

Ovarian grafting provides a strategy for clinical infertility treatment and is starting to be used in conjunction with ovarian tissue storage for patients at risk of early ovarian failure. As patients are starting to return for their frozen stored tissue we need to ascertain how to maximise follicle survival when this tissue is grafted back to the patient. For research purposes ovarian tissue is commonly grafted to the kidney capsule as the rich capillary bed at this site favours rapid graft revascularization. This is however not an ideal site for natural conceptions or for the harvest of mature oocytes for in vitro fertilization. While oocytes would be relatively easy to recover from grafts on the abdominal wall or subcutaneous tissue graft revascularization at these sites is slower and evidence indicates that fewer follicles survive. As gonadotropins can upregulate angiogenic growth factors in the ovary this study was designed to test whether the administration of exogenous gonadotropins would increase the number of surviving follicles in grafts placed at less vascularised sites. We showed that exogenous gonadotrophins, given to either the donor or the recipient, could increase the number of developing follicles but the magnitude of this effect was influenced by the timing of the injections relative to the time of grafting.

Evaluation of the long-term function of cryopreserved ovarian grafts in the mouse, implications for human applications

Ovarian tissue storage has several potentially very valuable clinical applications, including the management of young female patients that are at risk of premature menopause. Ovarian tissue collection, used alone or in combination with oocyte and embryo cryopreservation, may help these patients safeguard their own future fertility. All available evidence from animal studies indicates that grafting of frozen ovarian tissue should be feasible in the human. This study on the mouse shows that frozen thawed ovarian tissue grafts can restore long term fertility to previously ovariectomised recipients. This, and other available evidence, indicates that ovarian tissue collection and storage, used alone or in combination with oocyte or embryo collection, may help safeguard the fertility of patients at risk of premature menopause.

Fundamental cryobiology of mammalian oocytes and ovarian tissue

Embryo cryopreservation is a widely used and relatively well-established procedure. By contrast, ovarian tissue and unfertilized oocytes are only rarely cryopreserved, even though for germ line storage these often would be preferable to embryo cryopreservation. There are many reasons for this discrepancy. Unfertilized mature (MII) stage oocytes are more difficult to cryopreserve than cleavage stage embryos of the same species. Many factors contribute to this including the oocyte's surface to volume ratio, single membrane, temperature-sensitive metaphase spindle and zona, and its susceptibility to parthenogenetic activation and chill-injury. A completely different set of problems applies to primordial follicles. Oocytes in primordial follicles are very small and tolerate cryopreservation by slow cooling very well. The problem lies in the difficulty in producing mature oocytes from these primordial follicles. Better and/or more convenient cryopreservation procedures for both oocytes and ovarian tissue are being developed. This paper describes some of the advances in this area and outlines the relative merits and limitations of several currently available egg and ovarian tissue cryopreservation procedures.