Review: A barnyard in the lab: prospect of generating animal germ cells for breeding and conservation.

In vitro gametogenesis (IVG) offers broad opportunities for gaining detailed new mechanistic knowledge of germ cell biology that will enable progress in the understanding of human infertility, as well as for applications in the conservation of endangered species and for accelerating genetic selection of livestock. The realisation of this potential depends on overcoming key technical challenges and of gaining more detailed knowledge of the ontogeny and developmental programme in different species. Important differences in the molecular mechanisms of germ cell determination and epigenetic reprogramming between mice and other animals have been elucidated in recent years. These must be carefully considered when developing IVG protocols, as cellular kinetics in mice may not accurately reflect mechanisms in other mammals. Similarly, diverse stem cell models with potential for germ cell differentiation may reflect alternative routes to successful IVG. In conclusion, the fidelity of the developmental programme recapitulated during IVG must be assessed against reference information from each species to ensure the production of healthy animals using these methods, as well as for developing genuine models of gametogenesis.

Impact of Carbamide Peroxide Whitening Agent on Dentinal Collagen.

Carbamide peroxide (CP) is widely used as a tooth-whitening agent in self-administered tooth-bleaching products. In this study, the effects of 5% and 10% CP on dentinal collagen structure and chemical properties were evaluated in vitro. Thirty-five intact teeth were exposed to 2 whitening protocols (2 or 4 h daily) with either 5% or 10% CP gel for 1 wk. Shade changes before and after the whitening protocol were captured colorimetrically using a spectroshade. Collagen scaffold models and demineralized dentine disc samples were prepared and exposed to CP droplets (5% or 10%). Structural changes were investigated using electron microscopy. Finally, mineralized dentine disc samples were prepared postbleaching to assess chemical changes resulting from CP exposure in dentinal collagen using Raman spectroscopy. Results showed a difference in tooth shade when exposed to 5% and 10% CP whitening protocols, with a significantly ( P ≤ 0.01) greater change reported for the 10% CP/4-h group. Imaging of the collagen scaffold model following exposure to CP showed a gelatinization process indicating that the free radical by-products from CP are able to disrupt the quaternary structure of noncrosslinked collagen. The most significant damage on the collagen scaffold was seen for the 10% CP exposure for 4 h. Imaging of the demineralized discs displayed the same glassy amorphous layer appearance as found in the collagen scaffold. Raman spectra of the mineralized dentine discs showed a significant decrease ( P ≤ 0.01) in the integrated area of amide I and amide III values in the 4 test groups following CP application. Amide I was more affected as both the exposure time and concentration of CP increased. Despite the claimed safety of whitening agents, this in vitro study concludes that even low concentrations of CP result in a deleterious change in dentinal collagen.

Degradation pattern of a porcine collagen membrane in an in vivo model of guided bone regeneration.

BACKGROUND AND OBJECTIVE: Although collagen membranes have been clinically applied for guided tissue/bone regeneration for more than 30 years, their in vivo degradation pattern has never been fully clarified. A better understanding of the different stages of in vivo degradation of collagen membranes is extremely important, considering that the biology of bone regeneration requires the presence of a stable and cell/tissue-occlusive barrier during the healing stages in order to ensure a predictable result. Therefore, the aim of this study was to investigate the degradation pattern of a porcine non-cross-linked collagen membrane in an in vivo model of guided bone regeneration (GBR). MATERIAL AND METHODS: Decalcified and paraffin-embedded specimens from calvarial defects of 18, 10-month-old Wistar rats were used. The defects were treated with a double layer of collagen membrane and a deproteinized bovine bone mineral particulate graft. At 7, 14 and 30 days of healing, qualitative evaluation with scanning electron microscopy and atomic force microscopy, and histomorphometric measurements were performed. Markers of collagenase activity and bone formation were investigated using an immunofluorescence technique. RESULTS: A significant reduction of membrane thickness was observed from 7 to 30 days of healing, which was associated with progressive loss of collagen alignment, increased collagen remodeling and progressive invasion of woven bone inside the membranes. A limited inflammatory infiltrate was observed at all time points of healing. CONCLUSION: The collagen membrane investigated was biocompatible and able to promote bone regeneration. However, pronounced signs of degradation were observed starting from day 30. Since successful regeneration is obtained only when cell occlusion and space maintenance exist for the healing time needed by the bone progenitor cells to repopulate the defect, the suitability of collagen membranes in cases where long-lasting barriers are needed needs to be further reviewed.

A physiotherapy specialist clinic in paediatric orthopaedics: is it effective?

A physiotherapy specialist clinic was set up to reduce waiting times for non-urgent, new paediatric orthopaedic referrals. The outcome was reviewed at a minimum of 12 months for 1046 referrals assessed in the physiotherapy support clinic to analyse its effectiveness. Altogether 114 patients failed to attend the clinic. The remaining 932 patients form the basis of this study. Ninety three percent of these patients were managed without direct consultant intervention-72% with advice and reassurance, 17% by referral to the physiotherapy department, and 4% with surgical appliances. Only 7% needed consultant evaluation. Median waiting time for non-urgent conditions was reduced from 72 weeks in May 1996 to five weeks in May 1999. A majority of the parents were satisfied with the clinic. The clinic was found to be cost effective. The success of the clinic was attributable to good cooperation between the consultant and physiotherapist and a well defined protocol for assessment and management of patients.

Traumatic hemipelvectomy associated with contralateral hip dislocation: case report.

A case of a 28-year-old man surviving traumatic hemipelvectomy is presented. This patient is the first reported survivor in Australia of traumatic hemipelvectomy and one of few survivors reported in the world literature. Accurate and rapid early management including good resuscitation, rapid transport to the operating room and an aggressive team surgical approach all contributed to survival. Acute complications can be kept to a minimum by adhering to the approach of rapid resuscitation and early intervention by a team of surgeons. Associated dislocation of the contralateral hip with sciatic nerve damage and subsequent heterotopic calcification has not been previously reported and presents a significant obstacle to rehabilitation. Early attention to the psychological status of the patient and early involvement of rehabilitation specialists is advocated.

Effect of electrohydraulic and extracorporeal shock waves on gastrointestinal cancer cells and their response to cytotoxic agents.

Electrohydraulic and extracorporeal shock waves were used to treat the colorectal and gastric cancer cell lines LIM 2412 and MKN45. The effect on viability, cell proliferation, and the action of antitumour drugs was studied. Results showed that electrohydraulic and extracorporeal shock waves were cytotoxic to all cell lines and also caused considerable inhibition of cell proliferation. A significant additional reduction in cell viability was achieved by shock waves in cancer cells treated with methotrexate, 5-fluorouracil, and vincristine. These data indicate that shock waves may be worthy of further evaluation in the treatment of gastrointestinal cancers.

Extracorporeal shock-wave lithotripsy for distal ureteric calculi.

The results of 67 consecutive patients referred to the New South Wales Lithotripter Centre with distal ureteric calculi were evaluated. All these patients were treated on the Dornier HM3 Lithotripter. Distal ureteric calculi were classified as those at, or distal to, the proximal margin of the sacro-iliac joint. Eleven patients with stones overlying the sacro-iliac joint were treated in the prone position, while 56 patients with stones distal to the sacro-iliac joint, were treated in the saddle (astride) position. Of the 64 patients in whom follow-up was available, 44 (69%) were rendered totally stone free by extracorporeal shock-wave lithotripsy (ESWL). Lithotripsy has proved an effective treatment for distal ureteric calculi and has rendered 69% of patients stone free with minimal morbidity. Stones overlying the sacro-iliac joint can be successfully treated in the prone position.

Differentiated teratoma of testis metastasizing as differentiated teratoma in adult.

An unusual case of adult teratoma of testis metastasizing in benign form in a thirty-one-year-old man is reported and the literature reviewed.

Management of refractory detrusor instability by transvesical phenol injection.

The results of transvesical phenol injection into the paravesical nerve plexuses are reported in 40 consecutive patients. A 58% success rate was achieved in the treatment of refractory detrusor instability and 73% success was seen in detrusor hyper-reflexia in 11 patients with multiple sclerosis. Urinary retention occurred in 8%. Troublesome complications were seen in 2 patients who had had previous pelvic radiotherapy, which should be regarded as an absolute contraindication to the procedure.

Selection of C3 alcohols by high and low ethanol selecting mouse strains and the effects on open field activity.

Mice of the high-ethanol selecting C57BL/6j strain consume significantly larger amounts of 10% solution of 1,2-propanediol and 1-propanol than the low-ethanol selecting DBA/2j strain. Both strains uniformly avoid a 10% solution of 1,3-propanediol and 2-propanol. Open field activity was tested 30 min after an IP injection of 3 different equimolar doses of each alcohol. An increase in activity was produced in the DBA/2j strain by high (0.003 ml/mg) and middle (0.0015 ml/lg) doses of 1,2-propanediol and by a low dose (0.0005 ml/mg) of 2-propanol. The C57BL/6j strain were unaffected by these doses. High doses of 2-propanol produced sleep in both strains with the DBA/2j strain sleeping significantly longer, and 1,3-propanediol produced depression in both strains. Death resulted in all animals following injections at the high (0.002 mg/gm) and medium (0.001 ml/gm) doses of 1-propanol while the low dose (0.0005 ml/gm) produced slight depression.