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Biomedical subjects

B Harvey

Publications and source records attributed to B Harvey.

71 records · Page 4Linked to original sources
PubMed1983

Permeability of intact and dechorionated zebra fish embryos to glycerol and dimethyl sulfoxide.

Intact developing embryos of the zebra fish Brachydanio rerio were exposed to [14C]DMSO and [3H]glycerol (1 M in Fish Ringer) to assess the degree of permeation of these cryoprotectants. Glycerol enters the embryo more easily, although reaching only about 8% of the expected equilibrium level after 2 hr at room temperature; DMSO reaches only about 2.5% of this level. In an attempt to identify the barrier to permeation, dechorionated embryos were similarly exposed to isotopic DMSO. Permeation increased severalfold, indicating that the chorion retards the free exchange of solute. Embryos are unaffected by exposure to 1 M DMSO in Fish Ringer at 23 degrees C for up to 1 hr. The number of embryos hatching after 1-hr exposure to DMSO at varying concentrations was significantly reduced at 1.5 and 2 M. Embryos exposed to 1 M glycerol for 1 hr at 23 degrees C showed disruption of periblast cells and separation of the blastoderm; it was impossible to remove glycerol either by abrupt or very slow dilution.

Animals↗
PubMed1983

Cooling of embryonic cells, isolated blastoderms, and intact embryos of the zebra fish Brachydanio rerio to -196 degrees C.

Single cells from the developing embryo of the zebra fish survive freezing when protected with 1 M DMSO and cooled to -196 degrees C in two steps. Cell survival drops from 85 to 26% when clumps of 5-10 cells are similarly frozen, and to 2% when isolated blastoderms are treated in the same way. This drastic decrease in survival is interpreted as an example of the "scale-up problem," in which diffusional barriers prevent cryoprotectant equilibration and osmotic dehydration in large cell assemblanges. Isolated blastoderms develop considerably in culture, and retain some of this ability following cooling to -25 degrees C after protection with DMSO or glycerol. Intact embryos protected with high concentrations of glycerol (2.8 M) tolerate slow cooling to -196 degrees C surprisingly well, with most of the embryonic cells morphologically intact and actively extruding lobopodia. Glycerol could, however, only be removed from cells by disrupting the embryo so that diffusional barriers were removed. DMSO (2.8 M) was ineffective in preserving embryos or cells cooled to -196 degrees C.

Animals↗
PubMed1983

Need for measles revaccination in adolescents: correlation with birth date prior to 1972.

Measles hemagglutination inhibition (HI) antibody titers of less than 1:4 were significantly (P less than 0.05) more prevalent among subjects born from 1962 through 1971 and vaccinated with a single dose of live measles virus vaccine at 12 months of age (14.5%) than among subjects born during the same years but vaccinated at 13 months or older (2.3%). For subjects born in 1972 through 1976, however, this difference was not statistically significant; titers of less than 1:4 occurred in 6.2% of those vaccinated at 12 months, compared to 0% in those vaccinated at 13 months or older. A decline in maternally derived measles HI antibody may be related to the increased rate of HI antibody titers of 1:4 or greater following vaccination of more recently born subjects. Following revaccination of subjects whose measles HI antibody titers were less than 1:4, measles HI titers were lower than would be expected after successful primary vaccination. Nevertheless, measles HI antibody persisted at a level of 1:4 or more until the latest titer measurement of this study (one to two years after revaccination) in 87.5% of those whose initial vaccination had been at 11 or 12 months of age. No adverse reactions to revaccination occurred. Revaccination programs should be considered for adolescents and young adults born before 1972 who received live measles virus vaccine at or before 12 months. Children born from 1972 through 1976 who were vaccinated at 12 months or later are not in need of revaccination.

Adolescent↗
PubMed1977

Measles immunization. Successes and failures.

As a result of a large outbreak of measles, measles hemagglutination inhibition (HI) titers were measured in 465 immunized children. Titers of less than 1:4 were found in 14.6% of children immunized at 12 months of age as compared to 5.2% of those immunized at 13 months of age or later. Measles antibody titers were higher in the mothers of seronegative children who had been immunized at 11 or 12 months of age than in the mothers of seroposotive children. Measles HI titers of 1:4 or more were present in 94% of children immunized at 13 months of age or later between 1962 and 1964. The findings suggest that vaccine failure and not waning antibody accounts for the majority of titers of less than 1:4 in immunized children. Reimmunization programs should be considered for those who were immunized before 13 months of age.

Adolescent↗
PubMedDate not supplied

Complications of complicated grief in renal failure.

This paper sets out to bring together recurrent themes in the understanding and care of patients with Chronic/End Stage Renal Failure centering on the key issue of loss. A multi-disciplinary conceptual framework is proposed based on three perspectives--Systemic, Existential and Narrative. The integrated framework for understanding the complexity of grief issues for dialysis and pre-dialysis patients focuses on the perception of self and the inter-relationship with others directly involved in their care.

Adaptation, Psychological↗
PubMedDate not supplied

Characteristics of infants who undergo neonatal autopsy.

To identify factors associated with the performance of a neonatal autopsy, we surveyed autopsy practice patterns in a tertiary care neonatal intensive care unit for 1 year. After 56 neonatal deaths, 33 (59%) autopsies were performed. We used multivariable analysis to compare the clinical and demographic characteristics of infants who had an autopsy with those who did not. We found two variables to be negatively correlated with having an autopsy performed: birth asphyxia (p < 0.05) and Medicaid coverage (p < 0.05). Early neonatal death (< or = 2 days of age) was not correlated with lack of an autopsy. Pulmonary hypoplasia occurred more often in the group having autopsy. However, only birth asphyxia was significantly correlated with lack of an autopsy after adjusting for other variables in the analysis. The primary cause of death was not associated with performance of an autopsy. We found no significant association between consent for autopsy and the characteristics of the physician requesting it. These data suggest that the infant's socioeconomic status and diagnosis may influence parental consent for autopsy. There may be other characteristics of physicians who request it, parents who consent, or other socioeconomic factors influencing consent for the neonatal autopsy.

Adult↗