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Biomedical subjects

J Atwater

Publications and source records attributed to J Atwater.

At least 19 recordsLinked to original sources
PubMed2001

The use of indoor air measurements to evaluate intrusion of subsurface VOC vapors into buildings.

The implementation of a risk-based corrective action approach often requires consideration of soil vapor migration into buildings and potential inhalation exposure and risk to human health. Due to the uncertainty associated with models for this pathway, there may be a desire to analyze indoor air samples to validate model predictions, and this approach is followed on a somewhat frequent basis at sites where risks are considered potentially significant. Indoor air testing can be problematic for a number of reasons. Soil vapor intrusion into buildings is complex, highly dependent on site-specific conditions, and may vary over time, complicating the interpretation of indoor air measurements when the goal is to deduce the subsurface-derived component. An extensive survey of indoor air quality data sets highlights the variability in indoor volatile organic compound (VOC) concentrations and numerous sources that can lead to elevated VOC levels. The contribution from soil vapor is likely to be small relative to VOCs from other sources for most sites. In light of these challenges, we discuss how studies that use indoor air testing to assess subsurface risks could be improved. To provide added perspective, we conclude by comparing indoor air concentrations and risks arising from subsurface VOCs, predicted using standard model equations for soil vapor fate and intrusion into buildings, to those associated with indoor sources.

Air Pollution, Indoor↗
PubMed1992

Out of the laboratory and into the community. 26 years of applied behavior analysis at the Juniper Gardens Children's Project.

Application of Skinner's principles to socially significant human behavior had been well articulated by 1968 (Baer, Wolf, & Risley, 1968). Applications of these principles by Baer, Wolf, Risley, Hall, Hart, Christophersen, and their colleagues were in evidence as early as 1964 in the homes, schools, and clinics of inner-city Kansas City, Kansas, at the Juniper Gardens Housing Project. The work continues relatively uninterrupted, having contributed extensively to the literature of applied behavior analysis and the lives of community residents. This article describes the project and illustrates how applied behavioral research was initiated and extended, how the work addressed general concerns in psychology, and how it continues to address contemporary concerns within the community.

Behavior Therapy↗
PubMed1981

Globin chain synthesis in Hb J Baltimore-beta (+)-thalassemia.

An American black family in whom hemoglobin J Baltimore and beta (+)-thalassemia genes coexisted is described. The proposita is a 23-year-old woman with a hemoglobin (Hb) level of 11.5 g/dl, microcytic, hypochromic indices, increased values of Hbs A2 and F, and alpha/non-alpha synthetic ratio of 1.52. Hbs A and J Baltimore (beta 16 Gly---Asp) constituted 12% and 81.3%, respectively, of her total hemoglobin. Her sister had a very similar peripheral blood picture, but Hbs A and J Baltimore constituted 6.8% and 85.5%, respectively, of her total hemoglobin, and the alpha/non-alpha synthetic ratio was 1.39. The mother had beta(+)-thalassemia trait only, a moderate degree of anemia, and greater synthetic imbalance (alpha/non-alpha raio of 1.73). These findings suggest that the presence of the Hb J Baltimore gene ameliorates the effects of a coexistent beta-thalassemia gene.

Adult↗
PubMed1980

Globin synthesis studies in a person heterozygous for alpha-thalassemia-2, Hb S and Hb G Philadelphia.

A 21-year-old American black female with mild anemia was found to be triply heterozygous for alpha-thalassemia-2, hemoglobin S and hemoglobin G Philadelphia. Hemoglobin A comprised 39% of her total hemoglobin. The alpha-thalassemia gene was expressed by an alpha/non-alpha synthesis of ratio of 0.79 +/- 0.09 and was equally unbalanced in the peripheral blood and the bone marrow. Globin synthesis studies indicated that the percentage of Hb G and Hb S in the peripheral blood is about 32% and 31% respectively. These values are due to the coexistent alpha-thalassemia-2 gene with the following most likely genotype: --alpha G/alpha alpha, beta A/beta S (or --alpha/alpha G alpha, beta A beta S).

Adult↗
PubMed1980

Linkage of alpha G-Philadelphia to alpha-thalassemia in African-Americans .

We have studied the inheritance of the alpha-chain hemoglobin variant Hb G-Philadelphia (alpha 2(68 Asn leads to Lys)Beta 2) in two African-American families. Expression of the alpha-globin loci was monitored by the percentage of Hb G in these individuals. The variant represented approximately 33% of the total adult hemoglobin in some and 50% in others. alpha-Globin gene fragments were analyzed by using restricton endonucleases that cleave outside (EcoRI), within (HindIII), and between (Bgl II) the normal duplicated alpha-globin loci (alpha alpha/alpha alpha). Individuals having 33% variant lack one functioning alpha gene (alpha G/alpha alpha); those with 50% variant lack two genes, one missing on each chromosome (alpha G/alpha). Inheritance of alpha G was therefore linked to that of a chromosome with only one functional alpha-globin gene locus. This locus is probably the result of a nonhomologous crossover. Our results also suggest equal expression of the alpha-globin loci in humans because the percentages of the variant could be explained solely on the basis of the total number of alpha genes present. The percentages of Hb G as well as other hematologic data all were consistent with the number of alpha-globin genes identified by restriction endonuclease mapping. Gene mapping yields a more precise determination of the number of alpha-globin genes than does study of globin synthesis.

Africa↗
PubMed1980

alpha Thalassemia and the expression of hemoglobin G-Philadelphia.

The findings presented for these two families help to explain the inheritance of alpha thalassemia, alpha-chain variants, and the relative expression of alpha genes. An 18.0-kb EcoRI fragment contains only one functional alpha gene, whereas a 20.5-kb fragment contains two. Individuals homozygous for the 18.0-kb EcoRI fragment also lack the 4.1-kb HindIII fragment that normally connects the centers of the duplicated alpha genes. These findings are consistent with a deletion involving the 5' alpha-gene locus. Presence of alpha G-Philadelphia in both families was found in association with the 18.0-kb EcoRI fragment; this short fragment was also found in an individual with alpha A. Inheritance of alpha G-Philadelphia at one alpha-gene locus was therefore also linked to the inheritance of alpha thalassemia due to a deletion involving the second alpha gene. The high percentage (46% to 48%) of alpha G found in some family members was due to alpha-thalassemia trait, or deletion of two alpha genes (-alpha G/-alpha); others with levels of variant of 32% to 34% were shown to have three functional alpha genes (-alpha G/alpha alpha). The genetic expression of the four normal alpha genes therefore appears to be equal and furthermore implies the existence of separate independently functioning transcriptional units for each of these genes in humans. It would be interesting to analyze the alpha genes in Afro-Americans reported to have alpha G-Philadelphia in the 20% to 25% range to determine whether the inheritance of alpha G can be linked to a normal alpha gene.

Base Sequence↗
PubMed1980

Alpha-gene deletions in black newborn infants with Hb Bart's.

The presence of increased Hb Bart's (gamma 4) in cord blood is believed to be an indication of alpha-thalassemia. We have used restriction endonuclease nalyses of DNA to compare the number of alpha-genes with the percentage of Hb Bart's in 6 older children who had Hb Bart's at birth and 17 newborns. Four children with > 2% Hb Bart's had Eco R1 alpha-gene patterns and hematologic data consistent with the presence of two alpha-genes, one per chromosome. Of the remaining 19 children, all of whom had < 2% Hb Bart's, 8 had 3, while 11 had 4 alpha-genes. Three infants with Hb Bart's between 1% or less Hb Bart's. infants with 3 alpha-genes may therefore have elevated or normal levels of Hb Bart's at birth. DNA analysis is the definitive method for the determination of heterozygous alpha-thalassemia syndromes in newborns.

Black People↗
PubMed1979

Interaction of alpha-thalassemia genes with each other and with HbC in an American black family.

The relative rates of in vitro synthesis of hemoglobin chains have been studied in an American black family in which the mother is doubly heterozygous for alpha-thalassemia and HbC and the father is heterozygous for alpha-thalassemia. The alpha/non-alpha synthetic ratio was equally unbalanced in both the bone marrow and the peripheral blood of the mother. Although HbC comprised 35% of her hemoglobin (compared to 42.2 +/- 2.2 in individuals with HbC trait and balanced globin synthesis), synthetic data showed that the newly synthesized beta C chain was 44% of the total newly synthesized beta chains. Isolated membranes contained more newly synthesized beta C than beta A chains. Three of the offspring were within the normal range, and the remaining three had alpha-thalassemia. There were two spontaneous abortions during the second trimester of pregnancy. Hydrops fetalis did not occur, and none of the children had HbH disease or HbC trait.

Anemia↗
PubMed1978

A simple test for detection of sickle hemoglobin in the neonatal period.

The ease of denaturation by shaking of a solution of oxyhemoglobin S (oxy-Hb S) forms the basis for a simple and reliable test for confirmation or rapid detection of Hb S in children and adults. Comparison of results of this test with those from agar gel electrophoresis in capillary blood samples from 187 black neonates at 2 to 7 days of life showed no overlap of the amounts of hemoglobin precipitated between the group of neonates with Hb S (5.7--12.0%) and that without Hb S (0--4.7%). These results indicate that the shaking test, by virtue of being simple, reliable and inexpensive, may be used to detect and confirm Hb S in large numbers of neonates before their discharge from the nursery.

Anemia, Sickle Cell↗
PubMed1978

Study of a kindred with partial deficiency of red cell 2,3-diphosphoglycerate mutase (2,3-DPGM) and compensated hemolysis.

A kindred with partial deficiency of red cell 2,3-diphosphoglycerate mutase (2,3-DPGM) was studied. The propositus presented with indirect hyperbilirubinemia, normal hemoglobin (15.8 g/dl), and elevated reticulocyte count (4.6%). The red cell 51Cr survival was decreased (tau1/2 16 days). Incubated osmotic fragility was normal; autohemolysis was increased and corrected with glucose and ATP. The P50 was 18.5 mm Hg (normal 25.5 +/- 3), but the stability, electrophoresis, and fingerprinting of hemoglobin were normal. The concentration of 2,3-diphosphoglycerate (2,3-DPG) was reduced to 43% of normal. Red cell 2,3-DPGM was decreased to 59% of normal; 2,3-DPG phosphatase was similarly decreased. All red cell glycolytic and hexose monophosphate shunt enzymes, glycolytic intermediates other than 2,3-DPG, and glucose consumption and lactate production were normal. Five family members showed similar hematologic findings. The deficiency appears to be secondary to decreased enzyme synthesis and to be inherited as an autosomal dominant trait in this family. Partial deficiency of 2,3-DPGM should now be considered in the differential diagnosis of compensated hemolysis associated with increased oxygen affinity.

Adult↗
PubMed1977

Hemoglobin S-O Arab-alpha-thalassemia: globin biosynthesis and clinical picture.

A 22 year old American negro with mild anemia was found to be triply heterozygous for hemoglobin S, hemoglobin O Arab and alpha thalassemia. Hemoglobin A was not detected in the subject's hemolysate. The alpha thalassemia gene was expressed by an alpha/non-alpha synthesis ratio of 0.71 plus or minus 0.07 and was equally rates unbalanced in the peripheral blood and the bone marrow. The total radioactivity of the abnormal chains was equal, indicating equal rates of transcription and translation of the abnormal structural genes. Since the rate of synthesis of betaS and betaO was equal to the proportions of these abnormal chains in the peripheral blood, the abnormal gene products were equally stable. The mildness of the anemia, compared to that of the other reported S-O Arab double heterozygotes, may be due to the moderating influene of the alpha thal gene.

Adult↗
PubMed1972

Hemoglobin Lepore trait: globin synthesis in bone marrow and peripheral blood.

There was decreased synthesis of the beta-globin chain in the peripheral blood, and equal synthesis of alpha- and non-alpha-chains in the bone marrow of three patients with hemoglobin Lepore trait, similar to the findings in patients with heterozygous beta-thalassemia. There is a relative instability of the synthetic mechanism for normal beta-chain in these patients.

Bone Marrow↗
PubMed1972

-thalassemia in the American Negro.

In Italian and Chinese patients with the alpha-thalassemia syndromes the production of alpha-chain of normal hemoglobin is decreased relative to that of beta-chain in reticulocytes. In this study the relative rates of alpha- and beta-chain synthesis were determined in members of three Negro families with alpha-thalassemia. Two of the families had members with hemoglobin H disease and alpha-thalassemia trait, while the mother of several children with alpha-thalassemia trait in the third family was doubly heterozygous for alpha-thalassemia and an alpha-chain mutant. The alpha/beta ratios of globin synthesis in the patients with hemoglobin H disease and alpha-thalassemia trait indicated less severe biochemical defects in the peripheral blood than those previously determined in Italian and Chinese patients. In the third family, there was a heterogeneity of expression of the gene for alpha-thalassemia, including patients with normal red cell indices and synthesis ratios. These findings differ from those previously described in patients with alpha-thalassemia from other racial groups. Hydrops fetalis due to homozygous alpha-thalassemia may not occur in the Negro because of the relatively mild thalassemic defect.

Adolescent↗
PubMedDate not supplied

Perspectives on the transition from preschool to kindergarten for children with disabilities and their families.

This article addresses the transition of young children from preschool programs that provide special education services to kindergarten or alternative elementary school placements. The roles of the child, family, and service providers in transition preparation, planning, implementation, and evaluation are described. Successful transitions include assessments of children's skills in meeting the demands of kindergarten programs, teaching these skills to children, and actively encouraging parent participation in plans and programs. Barriers to successful transitions include lack of time and funding to coordinate both parent activities and between-school arrangements. A critical area for future research is the long-term evaluation of the procedures described as "best practice," as well as the definition of what constitutes a successful transition.

Child, Preschool↗