Informed consent for the study of retained tissues from postmortem examination following sudden infant death.

OBJECTIVE: To develop an approach for seeking informed consent to examine tissues retained from a previous study of sudden infant death syndrome (SIDS) as part of a study on asthma, and to document responses and participation rate. DESIGN: Pilot open-ended approach to 10 volunteer SIDS parents, followed by staged approach (newsletter, mail and telephone call) to seek consent from the target SIDS families for the asthma study. PARTICIPANTS: Parents (n = 10) of SIDS infants known to SIDS and Kids Victoria and parents of SIDS infants (n = 107) from the 1991-2 SIDS in Victoria case-control study. MAIN OUTCOMES: Qualitative responses of the piloted parents and study parents, and participation rates. RESULTS: The pilot group responses were used to refine the written material to be provided. Of the 72 families for which contact details were available, 45 gave verbal consent for contact by the Victorian Institute of Forensic Medicine regarding the asthma study, three refused and 24 did not respond to two letters. Thirty-three completed consent forms, all positive for participation in the asthma study, giving a positive response rate of 73% (33/45). CONCLUSIONS: The use of postmortem tissue for research is acceptable to the next of kin when an approach is sensitive to their concerns and needs and is made by experienced counsellors from a familiar organisation. Despite the painful memories evoked by the approach of the research group, the acceptance rate among those who could be contacted was high.

Expression of functional receptor-coupled TRPC3 channels in DT40 triple receptor InsP3 knockout cells.

The TRPC3 channel, an intensively studied member of the widely expressed transient receptor potential (TRP) family, is a Ca(2+)-conducting channel activated in response to phospholipase C-coupled receptors. Despite scrutiny, the receptor-induced mechanism to activate TRPC3 channels remains unclear. Evidence indicates TRPC3 channels interact directly with intracellular inositol 1,4,5-trisphosphate receptors (InsP(3)Rs) and that channel activation is mediated through coupling to InsP(3)Rs. TRPC3 channels were expressed in DT40 chicken B lymphocytes in which all three InsP(3)R genes were deleted (DT40InsP(3)R-k/o). Endogenous B-cell receptors (BCR) coupled through Syk kinase to phospholipase C-gamma (PLC-gamma) activated the expressed TRPC3 channels in both DT40w/t and DT40InsP(3)R-k/o cells. The diacylglycerol (DAG) analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG) also activated TRPC3 channels independently of InsP(3)Rs. BCR-induced TRPC3 activation was blocked by the PLC enzymic inhibitor, U-73122, and also blocked by wortmannin-induced PLC substrate depletion. Neither U-73122 nor wortmannin modified either OAG-induced TRPC3 activation or store-operated channel activation in DT40 cells. Cotransfection of cells with both G protein-coupled M5 muscarinic receptors and TRPC3 channels resulted in successful M5 coupling to open TRPC3 channels mediated by PLC-beta. We conclude that TRPC3 channels are activated independently of InsP(3)Rs through DAG production resulting from receptor-mediated activation of either PLC-gamma or PLC-beta.

Asymptomatic syndrome of polycythemic hyperviscosity: effect of partial plasma exchange transfusion.

We determined the cerebral hemodynamic changes in infants with asymptomatic polycythemic hyperviscosity syndrome and whether treatment with partial plasma exchange transfusion (PPET) would affect hemodynamics as well as outcome. From a routine cord blood hematocrit screening, 71 babies were identified as needing to be tested for polycythemic hyperviscosity. In addition to clinical evaluation, each infant had radial artery hematocrit and viscosity determinations, blood gas determinations, cerebral blood flow velocity studies, cranial ultrasonography, and noninvasive intracranial pressure determination. Babies with symptomatic hyperviscosity (n = 17) were treated by PPET, whereas those with asymptomatic hyperviscosity (n = 28) were randomly selected to have PPET (n = 14) or to be observed (n = 14). The remaining babies (n = 26) with normal viscosity served as control subjects. Both hematocrit and viscosity decreased after PPET but remained unchanged in babies with hyperviscosity who were merely observed. Reversal of cerebral blood flow velocity abnormalities was observed after PPET in the infants with symptomatic hyperviscosity, whereas those who had no symptoms had normal results on Doppler studies at the outset, and no significant changes occurred with either PPET or observation. There were two deaths in the group with symptoms. A total of 46 babies returned for follow-up evaluation at a mean age of 30 +/- 7.7 months. Outcome of the control group was no better than that of those who had hyperviscosity, and outcomes did not differ between the babies with symptomatic and those with asymptomatic hyperviscosity, nor between those treated with PPET and those who were only observed. Multivariate analysis revealed that other perinatal risk factors and race rather than polycythemia or PPET, significantly influenced long-term outcome.

Intact biliary excretion of gastrically administered prostaglandin F2 alpha in rats: developmental differences.

Tritium-labeled prostaglandin F2 alpha was administered via orogastric tube to bile duct-cannulated suckling and weanling rats to determine if maturational differences were present in the biliary excretion of prostaglandin F2 alpha and metabolites. Animals were killed 2 h after radioactivity administration. Characterization of radioactivity present in bile revealed age-related differences in biliary prostaglandin F2 alpha excretion. Suckling rats had a greater proportion of radioactivity migrating in chromatographic regions of greater polarity than prostaglandin F2 alpha. Compared with the weanling, a significantly greater amount of radioactivity cochromatographed with intact, unmetabolized prostaglandin F2 alpha (33.08 +/- 1.99 vs. 21.38 +/- 1.46). These results indicate that orogastrically administered prostaglandin F2 alpha can be absorbed from the gastrointestinal tract, transported to the liver, and subsequently excreted into bile and detected in an unmetabolized form in suckling and weanling rats. The enterohepatic circulation of milk-derived prostaglandin present in bile may contribute to the overall content of intestinal prostaglandins.

Partial plasma exchange transfusion improves cerebral hemodynamics in symptomatic neonatal polycythemia.

Cerebral arterial pulsatile flow changes and the effect of partial plasma exchange transfusion on these pulsatile flow patterns were studied in neonatal polycythemia/hyperviscosity syndrome by transcutaneous Doppler technique. Twenty-two infants with cord blood hematocrit greater than 58% (greater than 2 SD above the mean) were studied from a total of 2,400 infants who were screened for cord hematocrit over a 6-month period. Each of 22 infants had the following initial studies: radial artery hematocrit, viscosity, intracranial pressure measurement, and anterior cerebral arterial Doppler study to determine pulsatility index, mean systolic, mean end diastolic, and mean flow velocities, and area underneath the curve of the velocity tracings/min. Twelve of 22 infants had radial artery hematocrit less than 63%, were normoviscous (less than 13.5 cps, 11.25 sec-1) and were designated as control infants. Ten (study infants) were polycythemic (hematocrit greater than or equal to 63%) and hyperviscous (greater than or equal to 13.5 cps, 11.25 sec-1). All study patients were treated by partial plasma exchange transfusion. Initial studies were repeated after exchange transfusion. Control infants were not treated. Prior to exchange procedure, the polycythemic hyperviscous infants had significantly higher hematocrit, viscosity, and pulsatility index; the other Doppler measurements and heart rate were lower than those of control babies. The exchange procedure resulted in significantly decreased hematocrit, viscosity, and pulsatility index and increase in the other Doppler measurements, heart rate, and intracranial pressure. All postexchange measurements of study infants were not statistically different from the control infants. These data suggest that neonatal polycythemia/hyperviscosity syndrome may be associated with abnormal cerebral hemodynamics that could improve with partial plasma exchange transfusion.

Econometric Modeling Of Individual And Social Multi-Attribute Utility Functions.

Econometric techniques for estimating the parameters of individual and composite (group) multi-attribute utility (MAU) models are discussed. These techniques permit measurement of intra- and inter-individual heterogeneity with regard to the importance ascribed to the model attributes. Using data from an experimental task in a simulated university environment, which involved developing criteria for evaluating faculty teaching performance, it is shown that the usual method of ordinary least squares (OLS) can be inaccurate and information restrictive. Implications for design and staffing as well as optimization and implementation of organizational and societal decisions are discussed.

Effectiveness of audio-based instruction in medical pharmacology.

An audio-based method of instruction on the topic of diuretic drugs was compared with the lecture method using a random sample of 66 sophomore medical students. A cognitive test given to measure achievement as a result of the two treatments showed that the average score of 80 percent for the audio group was significantly higher (p smaller than 0.25) than the 75 percent for the lecture group. A comparison of the lowest quartile scores in each group revealed that the audio-based group also scored higher 13 points, p smaller than .05) than the lecture group; however, no difference was noted in the upper three quartile scores of the two groups. The amount of time spent studying did not appear to be a factor. A second test given to meausre attitudes toward the audio method showed strong positive views among students.

The strengths of the N(2)O bands near 4.5 micro.

The combined intensities at 300 degrees K of the N(2)O bands near 4.5 micro have been determined to be 1920 +/-50 cm(-1) (atm-cm NTP)(-1). The measurements were made on a grating, double beam, spectrophotometer. The tests made to estimate the accuracy and reproducibility of this instrument are described.