Blood lymphocyte chimerism associated with IVF and monochorionic dizygous twinning: case report

We report on dizygotic (DZ) twins, conceived by IVF and ICSI with assisted hatching, who each had a mixture of 46,XX and 46,XY cells in blood lymphocytes. The female twin had mild genitalia abnormalities but further study revealed anatomically normal reproductive anatomy. Chromosome and fluorescence in situ hybridization studies of buccal, skin and ovarian tissue were normal, as were buccal tissue DNA studies. Fetal ultrasound and fetal membrane pathology were consistent with a monochorionic, diamniotic placenta (MCDAP). These twins thus have blood chimerism but are not chimeric in the other tissues studied. The mechanism for the chimerism could be due to either placental vascular anastamoses (after the development of the haematoblast stem cells) or due to an admixture of trophoblast cells during early blastocyst development. Such trophoblast cell admixtures would be restricted to the extraembryonic tissues so that general physical development in the fetus is normal and without somatic cell chimerism. This case in combination with others previously reported suggests that in IVF conceptions, the prevalence of blood chimerism associated with twinning, and the occurrence of DZ twinning associated with MCDAP, may be higher than previously thought.     

Different levels of polybrominated diphenyl ethers (PBDEs) and chlorinated compounds in breast milk from two U.K. Regions

Polybrominated diphenyl ether (PBDE) congeners are constituents of flame retardants, and there is growing concern regarding their persistence, bioaccumulation, and toxicity. We collected breast milk samples between late 2001 and early 2003 from 54 U.K.-resident mothers. Of these, 27 originated from southeast England (London), and the other 27 originated from northwest England (Lancaster). Analysis of milk-fat extracts by gas chromatography-mass spectrometry was performed to determine the levels of 15 PBDE congeners, 15 polychlorinated biphenyl (PCB) congeners, and other selected chlorinated compounds. PCB and organochlorine (OC) levels in southeast samples were consistently higher, and significant differences (p < 0.05) were observed. Sigma PBDE levels ranged from 0.3 to 69 ng/g lipid (geometric mean, 6.6 ng/g), and PBDE-47 was the most abundant congener. Sigma PCB levels ranged from 26 to 530 ng/g lipid (geometric mean, 150 ng/g) and were composed mainly of PCB-153 (26%), PCB-138 (20%), and PCB-180 (13%). OC levels for 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and its metabolites (Sigma DDX) ranged from 24 to 2,300 ng/g lipid (geometric mean, 160 ng/g);Sigma hexachlorocyclohexane levels ranged from 1.2 to 1,500 ng/g lipid (geometric mean, 16 ng/g). Using nuclear magnetic resonance-based metabonomics, samples (n = 7) containing the highest contaminant levels were compared with samples (n = 7) containing the lowest levels. Excellent separation along the first principal component implied that the chemical constituents of the two groups were significantly different. Although reasons for such differences remain obscure, lifestyle factors associated with a more heterogeneous London cohort could be responsible. Identifying primary routes of contaminant exposures and their biologic effects is of great importance. Key words: breast milk, flame retardants, gas chromatography-mass spectrometry, milk-fat extracts, organochlorines, PBDE-47, persistent contaminants, polybrominated diphenyl ethers, polychlorinated biphenyls, United Kingdom.     

Hydrogels for tissue engineering: scaffold design variables and applications

Polymer scaffolds have many different functions in the field of tissue engineering. They are applied as space filling agents, as delivery vehicles for bioactive molecules, and as three-dimensional structures that organize cells and present stimuli to direct the formation of a desired tissue. Much of the success of scaffolds in these roles hinges on finding an appropriate material to address the critical physical, mass transport, and biological design variables inherent to each application. Hydrogels are an appealing scaffold material because they are structurally similar to the extracellular matrix of many tissues, can often be processed under relatively mild conditions, and may be delivered in a minimally invasive manner. Consequently, hydrogels have been utilized as scaffold materials for drug and growth factor delivery, engineering tissue replacements, and a variety of other applications.     

The apoptotic profile of human cumulus cells changes with patient age and after exposure to sperm but not in relation to oocyte maturity

OBJECTIVE: To determine the expression of apoptosis-associated molecules on cumulus cells removed from individual oocytes of different maturity, inseminated oocytes and to investigate the possibility of an age-dependent expression. DESIGN: Analysis of apoptosis in cumulus cells isolated from oocytes of different stages of maturity. SETTING: Assisted reproductive technology program of the Birmingham Women's Hospital, Birmingham, UK. PATIENT(S): Patients undergoing intracytoplasmic sperm injection or IVF cycles. MAIN OUTCOME MEASURE(S): Percentage of positive cumulus cells when assessed for nuclear DNA damage using the terminal deoxyuridine nucleotide end-labeling assay or stained with antibodies [Fas, Fas ligand, the antiapoptotic protein Bcl-xl, and the RNA-binding protein (TIAR)]. RESULT(S): Cumulus cells collected from mature oocytes showed no significant difference in the percentage of apoptotic markers compared to those recovered from immature oocytes, whereas those from patients >/=38 years differed significantly. When cumulus cells were exposed to sperm the levels of apoptotic markers altered significantly from those not exposed to sperm. CONCLUSION(S): The results show that the cumulus cells of human oocytes are equipped with a mechanism to undergo apoptosis and that patient age and the exposure of cumulus cells to sperm can alter their profiles of apoptotic markers.     

Oral cancer knowledge and opinions among Maryland nurse practitioners

OBJECTIVES: As part of a Maryland statewide oral cancer needs assessment, a census of adult and family practice nurse practitioners was conducted to determine their knowledge of oral cancer risk factors, diagnostic procedures and related opinions. METHODS: Information was obtained through a pretested, 40-item, self-administered mail questionnaire of 389 nurse practitioners. A second complete mailing was sent three weeks after the initial mailing; two postal card reminders were mailed at 10 and 17 days after the second mailing, which yielded a response rate of 56 percent. RESULTS: Most nurse practitioners identified the use of tobacco, alcohol, and prior oral cancer lesions as real risk factors. But only 35 percent identified exposure to the sun as a risk for lip cancer. Respondents were not overly knowledgeable about the early signs of oral cancer, most common forms, or sites for oral cancer. Only 19 percent believed their knowledge of oral cancer was current. Nurse practitioners who reported having a continuing education course on oral cancer within the past two to five years were 3.1 times more likely to have a high score on knowledge of risk factors and 2.9 times more likely to have a high score on knowledge of both risk factors and of diagnostic procedures than were those who had never had a continuing education course. CONCLUSIONS: The reported knowledge of oral cancer, in conjunction with opinions about level of knowledge and training, point to a need for systematic educational updates in oral cancer prevention and early detection.     

The development of a national agreed minimum diabetes dataset for New Zealand

The development of a minimum diabetes dataset (MDD) for monitoring diabetes in New Zealand was intended to facilitate diabetes quality initiatives. Existing published datasets were reviewed and a draft MDD for New Zealand was distributed to all 147 specialist, general practice and relevant community groups. Data definitions were either identical or compatible with other datasets and dataset items included if there were at least six supportive replies. All groups were followed up by letter and telephone. A total of 26 (18%) replies were received. Comments were reviewed and the recommended MDD finalised. There was agreement that this dataset would be embedded into the software of at least three commercially available patient management systems. In conclusion, developling an agreed national MDD was difficult, in spite of its potential utility for local, regional and national collation of diabetes data allowing those involved to generate a picture of diabetes and its outcomes.