Cytogenetic analysis of unfertilized human oocytes

Cytogenetic studies were carried out on 180 oocytes that appeared unfertilized after in-vitro fertilization. The majority of the 135 that were informative had grossly haploid second meiotic metaphases, two were grossly diploid, and five had a variety of different abnormalities. Twenty-one oocytes were abnormally fertilized and included prematurely condensed sperm chromosomes. The frequency of this phenomenon varied according to the stimulation protocol, those oocytes maturing longer in vivo showing less propensity to abnormal fertilizations. Thirteen per cent of the analysable haploid metaphases were hyperhaploid but none contained extra whole chromosomes. The extra components were a single chromatid (one case), or two single chromatids replacing a whole chromosome (four cases). The data suggest that the chromatids arose as a result of premature centromere division at meiosis I, and that this may be a major mechanism for trisomy formation rather than non-disjunction of whole bivalents at meiosis I, as generally believed.     

Gain of 1q and loss of 22 are the most common changes detected by comparative genomic hybridisation in paediatric ependymoma

Ependymomas are the third most common brain tumour in the paediatric population. Although cytogenetic and molecular analyses have pinpointed deletions of chromosomes 6q, 17, and 22 in a subset of tumours, definitive patterns of genetic aberrations have not been determined. In the present study, we analysed 40 ependymomas from paediatric patients for genomic loss or gain using comparative genomic hybridisation (CGH). Eighteen of the tumours (45%) had no detectable regions of imbalance. In the remaining cases, the most common copy number aberrations were loss of 22 (25% of tumours) and gain of 1q (20%). Three regions of high copy number amplification were noted at 1q24-31 (three cases), 8q21-23 (two cases), and 9p (one case). Although there was no association with the loss or gain of any chromosome arm or with benign versus anaplastic histologic characteristics, the incidence of gain of 7q and 9p and loss of 17 and 22 was significantly higher in recurrent versus primary tumours. This study has identified a number of chromosomal regions that may contain candidate genes involved in the development of different subgroups of ependymoma.     

Myositis associated with a newly described microsporidian, Trachipleistophora hominis, in a patient with AIDS.

Microsporidia are zoonotic protozoa which were rare human pathogens prior to 1985, when Enterocytozoon bieneusi was described in human immunodeficiency virus-infected patients with chronic diarrhea. Another species, Encephalitozoon (Septata) intestinalis, is associated with diarrhea and chronic sinusitis, and approximately 25 cases have been reported in the literature. However, other microsporidial infections in human immunodeficiency virus-infected patients remain extremely rare. We report the first case of a Pleistophora sp.-like microsporidian infection presenting as a progressive severe myosotis associated with fever and weight loss. The organism was demonstrated by light microscopy and electron microscopy in corneal scrapings, skeletal muscle, and nasal discharge. Electron microscopy showed an electron-dense surface coat with "sunflare"-like projections surrounding all stages of development of meronts (two to four nuclei, dividing by binary fission), sporonts, and sporoblasts. Division of sporonts, in which sporonts separate from the thick outer coat, creating a sporophorous vesicle, is by binary fission, differentiating this organism from Pleistophora sp. The spore measures 4.0 by 2.5 microns and has a rugose exospore. A new genus and species, Trachipleistophora hominis, has been established for this parasite. The patient was treated with albendazole, sulfadiazine, and pyrimethamine, and the clinical symptoms resolved.     

The generation of life events in recurrent and non-recurrent depression

BACKGROUND: The stress generation hypothesis proposed by Hammen (1991) holds that depressed individuals generate stressful conditions for themselves, which lead to recurrence. The original test of this hypothesis compared dependent life events in women with recurrent depression to medical and normal controls. Two further research questions emerged from this work: (a) do individuals with a history of many depressive episodes generate more dependent life events than depressives with fewer episodes?; and (b) what is the aetiological relevance of any stress that may be generated? METHODS: The present research tested differences in dependent and independent events between depressed individuals who had experienced: (a) no previous major depressive episodes; (b) one previous episode; and (c) two or more previous episodes. We predicted that, based on the stress generation hypothesis, recurrent depressives would show more dependent events than people without a depression history, and that these generated stressors would be of aetiological importance for precipitating recurrence (i.e. severe events in the 3 months preceding recurrence). RESULTS: Recurrent depressives experienced significantly more total dependent events than first-onset depressives in the 12 months, but not the 3 months, preceding their episode. CONCLUSIONS: Although the findings supported the general premise of stress generation, the aetiological relevance of the generated stress for recurrence requires further study.     

The Spoke-Hub-and-Node Model of Integrated Heart Failure Care

Heart failure (HF) is a significant public health concern. Specialized HF clinics provide the optimal environment to address the complex needs of these patients and improve outcomes. The current and growing population of patients with HF outstrips the ability of these clinics to deliver care. Integrated care is defined as health services that are managed and delivered so that people receive a seamless continuum of health promotion, disease prevention, diagnosis, treatment, disease management, rehabilitation, and palliative care services. This approach requires coordination across different levels and sites of care within and beyond the health sector, according to changing patient needs throughout their lives. The spoke-hub-and-node (SHN) model represents an organization of care that works collaboratively with the primary care sector and is highly integrated with community-based multidisciplinary teams of health care professionals and specialty care. The purpose of this article is to analyze the requirements for successful implementation of SHN models. We consider the respective roles of HF clinics, HF nurse specialists, pharmacists, palliative care teams, telemonitoring, and solo practitioners. We also discuss levels of care delivery and the importance of patient stratification and patient flow. The SHN approach has the potential to build on and improve the chronic care model (CCM) to deliver centralized services to preserve high-quality patient-centred care at affordable costs.     

Outcomes of Donation After Circulatory Death Heart Transplantation in Australia

Background

Transplantation of hearts retrieved from donation after circulatory death (DCD) donors is an evolving clinical practice.

Demonstrated Efficacy of a Pilot Heterologous Whole-Spore Vaccine against Microsporidial Gill Disease in Rainbow Trout

Intraperitoneal vaccines using whole viable spores of the microsporidian Glugea anomala or Glugea hertwigi reduced the numbers of branchial xenomas by 80% and 91%, respectively, after a standard experimental infection of juvenile rainbow trout with the microsporidian Loma salmonae. Similar significant results were obtained when killed-spore preparations were used.