Age-related neurochemical and behavioural changes in D409V/WT GBA1 mouse: Relevance to lewy body dementia

Heterozygous mutations in GBA1, the gene which encodes the lysosomal enzyme glucocerebrosidase (GCase), are a strong genetic risk factor for the development of Lewy body dementia (LBD). Until this point however, recapitulation of the symptoms and pathology of LBD has been limited to a homozygous GBA1 mouse model which genetically and enzymatically reflects the lysosomal storage disorder Gaucher's disease. This study reports for the first time cognitive impairment by two independent behavioural tests in heterozygous GBA1 mutant mice (D409V/WT) which demonstrate significant cognitive impairment by the age of 12 months. Furthermore, reductions in GBA1 GCase enzyme activity within the brain reflects levels seen in sporadic and GBA1 mutant LBD patients. While there is no overt deposition of Lewy bodies within the hippocampus, alterations to cholinergic machinery and glial proliferation are evident, both pathological features of LBD. Interestingly, we also describe the novel finding of significantly reduced GBA2 GCase enzyme activity specifically within the hippocampus. This suggests that reduced GBA1 GCase enzyme activity dis-equilibrates the finely balanced glycosphingolipid metabolism pathway and that reductions in GBA2 GCase enzyme could contribute to the pathological and behavioural effects seen. Overall, this study presents evidence to suggest that pathological hallmarks associated with LBD specifically affecting brain regions intrinsically linked with cognition are present in the D409V/WT mice. In the absence of Lewy body deposition, the D409V/WT mice could be considered an early pre-clinical model of LBD with potential for drug discovery. Since few robust pre-clinical models of LBD currently exist, with further characterization, the mouse model described here may contribute significantly to developments in the LBD field.

Diagnostic investigation of parotid neoplasms: a 16-year experience of freehand fine needle aspiration cytology and ultrasound-guided core needle biopsy

This study aimed to examine the diagnostic yield of fine needle aspiration cytology (FNAC) and ultrasound-guided core needle biopsy (USCB) in the diagnosis of parotid neoplasia. A 16-year retrospective analysis was performed of patients entered into our pathology database with a final diagnosis of parotid neoplasia. FNAC and USCB data were compared to surgical excision where available. One hundred and twenty FNAC, 313 USCB, and 259 surgical specimens were analyzed from 397 patients. Fifty-six percent of FNAC and 4% of USCB were non-diagnostic. One hundred and thirty-two (33%) patients had a final diagnosis made by USCB and did not undergo surgery. Surgery was performed in 257 (65%) patients, 226 (88%) of whom had a preoperative biopsy. Most lesions were benign, but there were 62 parotid and 13 haematological malignancies diagnosed; false-negative results were obtained in three FNAC and two USCB samples. The sensitivity and specificity of FNAC were 70% and 89%, respectively, and for USCB were 93% and 100%, respectively. This study represents the largest series of patients with a parotid neoplasm undergoing USCB for diagnosis. USCB is highly accurate with a low non-diagnostic rate and should be considered an integral part of parotid assessment.

Chronic inactive pulmonary tuberculosis and treatment sequelae: chest radiographic features

The chest radiograph (CXR) is a key initial tool in the diagnosis of many lung conditions, including pulmonary tuberculosis (TB). With proper use of anti-tuberculosis drugs, TB can be treated effectively and many CXR changes are limited. However, anti-tuberculosis drugs have not always been available, and in some cases they have not been started early in the disease process. The infection has then been able to take hold and cause significant radiologically visible damage, such as calcification and fibrosis. Before the use of anti-tuberculosis drugs, a variety of surgical techniques were employed to control pulmonary infection, including plombage, oleothorax, phrenic nerve crush and thoracoplasty. Each of these led to distinctive CXR features. This article sets out to describe the CXR features of chronic disease and surgical treatments, as their increasing rarity with the passage of time has meant that they can be misinterpreted. However, with increasing life expectancy and the revival of surgery due to the development of anti-tuberculosis drug resistance, the correct interpretation of these CXR changes is still of importance.

Towards defining parameters for a successful single embryo transfer in frozen cycles

BACKGROUND

Twin pregnancies in IVF should be avoided by transferring embryos one at a time, even for frozen cycles. In this study, we investigated the effect of blastomere lysis and cleavage in singleton frozen embryo transfer (sFET) cycles. Outcomes were compared with the transfer of two embryos in frozen transfer cycles (dFET).

METHODS

A retrospective analysis was performed on 891 FET cycles, involving 404 sFET and 487 dFET cycles.

RESULTS

Overall, in sFET cycles, the pregnancy and implantation rates were 8.9 and 8.7%. When blastomere lysis was more than 25% but no greater than 50%, the pregnancy and implantation rates were 3.2%. If blastomere lysis was greater than 50% there were no pregnancies. If blastomere lysis was less than 25%, but with no cleavage, the pregnancy and implantation rates were 4.1%. The results significantly improved (P = 0.007) in the group with less than 25% lysis, when cleavage occurred. The pregnancy and implantation rates for this group were 17.3 and 16.6%. This was not significantly different from unselected two embryo transfers (22 and 12.7%,P = 0.2 and 0.19, respectively). There were 21 twins with dFET (19.6% of pregnancies) and none in sFET.

CONCLUSION

Both blastomere lysis and cleavage affect the outcome in sFET. To avoid the risk of twins, sFET should be considered when the embryo shows less than 25% blastomere lysis and at least one blastomere cleaves.

Hemin and related porphyrins inhibit beta-amyloid aggregation

Porphyrins related to the naturally occurring pigment heme were found to effectively interfere with the aggregation of beta-amyloid peptides as determined by an immunoassay configured for the detection of beta-amyloid oligomers. Oligomerisation of beta-amyloid is believed to be a key event in the progression of Alzheimer's disease. Inhibition of this aggregation is thus an important strategy in combating this commonest form of senile dementia. Evidence was also generated for hemin and hematin mediated protection of cultured cells against the neurotoxic effects of beta-amyloid. These data are discussed with reference to the known pathology of Alzheimer's disease and the chemistry of porphyrins.

The search for donor eggs: a problem of supply and demand

Although seven babies who were conceived in vitro with donated oocytes have been born in the Monash-Epworth programme, the availability of this service is now threatened because of the scarcity of oocytes for donation. Previously oocytes were donated by infertile women undergoing oocyte collection in the in vitro fertilisation programme, but this supply has been severely curtailed since cryopreservation of their embryos has been made available to them. Other sources of donated oocytes have included collecting oocytes from women undergoing laparoscopic sterilization, infertile women finding their own (known) donors, and fertile women donating all their oocytes for altruistic reasons on an in vitro fertilisation programme. The latter two categories offer the greatest chance of collecting mature oocytes for donation.

Cross-over trial of superovulation protocols from two major in vitro fertilization centers

A study was undertaken as a controlled comparison of two different superovulation induction protocols currently in use in major Australian in vitro fertilization (IVF) clinics. Thirty patients each from the Monash University and the Royal Women's Hospital (RWH) IVF programs were stimulated for ovulation induction by the other program. Once timing for oocyte retrieval was scheduled, all care reverted to the program from which the patient first came. Results given as pregnancies per patient commencing stimulation were: RWH patients on Monash protocol, 27%; RWH control patients, 15%; Monash patients on RWH protocol, 7%; Monash control patients, 13%. In the year preceding the trial pregnancy rates were 16.9% at Monash and 10.6% at RWH. Stimulation protocols were also compared with respect to each of administration, cost, and patient stress. The results of this cross-over trial demonstrated major differences between the two ovulation induction protocols studied, although it was not possible to conclude that differences in pregnancy rate were due to stimulation alone.

The effect of progesterone supplementation around the time of oocyte recovery in patients superovulated for in vitro fertilization

A randomized control trial involving 42 superovulated in vitro fertilization (IVF) patients was carried out to investigate the effects of providing supplementary progesterone (P) around the time of laparoscopy. P was given 12 to 15 hours and 1 hour before and 24 hours after laparoscopy in one group (group B); human chorionic gonadotropin was given 12 hours before laparoscopy in another group (group C); and the remainder received no treatment in addition to normal IVF procedures (group A). There was no difference in fertilization rate, the proportion of normally developing embryos, pregnancy rate, or birth rate between the treatment groups, We conclude that in the superovulation schedule used, P supplementation around the time of laparoscopy does not affect success rate of IVF.