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Biomedical subjects

E Baker

Publications and source records attributed to E Baker.

At least 217 records · Page 12Linked to original sources
PubMed1990

An expanded mouse-human hybrid cell panel for mapping human chromosome 16.

A mouse/human hybrid cell panel of human chromosome 16 has been extended to a total of 31 hybrids. These hybrids were derived from constitutional translocations and deletions ascertained during clinical cytogenetic studies. This panel of hybrids, together with four fragile sites, have the potential to divide chromosome 16 into 38 regions. Rapid detailed physical mapping of gene probes or anonymous DNA probes is possible using this hybrid panel. This hybrid cell panel also allows the physical mapping of other chromosomes with three breakpoints on chromosomes 1, 4, 11 and 13 and two on chromosomes 3, 10 and 18.

Animals↗
PubMed1990

Reassessment of two apparent deletions of chromosome 16p to an ins(11;16) and a t(1;16) by chromosome painting.

Two apparent deletions of the short arm of chromosome 16 were studied by in situ hybridisation using biotinylated DNA from a chromosome 16 specific cosmid library (chromosome painting). One abnormality was delineated as a t(1;16)(p36;p12) and the other as a ins(11;16)(q13;p13.13p13.3). Apparently unbalanced de novo abnormalities detected by classical cytogenetic procedures should be interpreted with caution. In situ hybridization using DNA from chromosome specific libraries provides the appropriate technology to delineate such abnormalities.

Adult↗
PubMed1990

Chromosomal localization of the human alpha-L-iduronidase gene (IDUA) to 4p16.3.

The lysosomal hydrolase alpha-L-iduronidase (IDUA) is one of the enzymes in the metabolic pathway responsible for the degradation of the glycosaminoglycans heparan sulfate and dermatan sulfate. In humans a deficiency of IDUA leads to the accumulation of glycosaminoglycans, resulting in the lysosomal storage disorder mucopolysaccharidosis type I. A genomic subclone and a cDNA clone encoding human IDUA were used to localize IDUA to chromosome 4p16.3 by in situ hybridization and this was confirmed by Southern blot analysis. This localization is different from that of a previous report mapping IDUA to chromosome 22 and places the gene for IDUA in the same region of chromosome 4 as the Huntington disease gene. Measurement of expressed human IDUA activity in human-mouse hybrid cell lines confirmed that IDUA is on chromosome 4.

Animals↗
PubMed1990

Erythroid 5-aminolevulinate synthase is located on the X chromosome.

The gene for erythroid 5-aminolevulinate synthase has been mapped to Xpter-Xq26 by Southern blot hybridization analysis of a mouse/human hybrid cell panel. In situ hybridization maps the gene to Xp21-Xq21, with the most likely location being on band Xp11.2. The mapping of the erythroid 5-amino-levulinate synthase gene to the X chromosome suggests that a defect in this gene may be the primary cause of X-linked sideroblastic anemia.

5-Aminolevulinate Synthetase↗
PubMed1990

The isochromosome 18p syndrome: confirmation of cytogenetic diagnosis in nine cases by in situ hybridization.

Nine cases are described of tetrasomy 18p resulting from the presence of an isochromosome 18p [i(18p)]. The initial diagnosis of i(18p) was by standard cytogenetic techniques and was confirmed by in situ hybridization with a biotinylated alphoid probe (L1.84) specific for the pericentric region of chromosome 18 and with a tritium-labeled chromosome 18 probe (B74) which hybridizes to the D18S3 locus situated at 18p11.3. The clinical features of the cases are summarized and shown to constitute a distinct and recognizable syndrome. Common features were low birth weight, a characteristic facies, neonatal hypotonia with subsequent limb spasticity, short stature, microcephaly, mental retardation, and seizure disorders. On the basis of size and cytogenetic banding a marker chromosome can be suspected to be an i(18p). In situ hybridization with the alphoid probe L1.84 provides confirmation of chromosome 18 origin. This more precise diagnosis will be an advantage in situations of pre- and postnatal diagnosis, since parents can be provided with a more confident prognosis for their child.

Abnormalities, Multiple↗
PubMed1989

A new DNA marker tightly linked to the fragile X locus (FRAXA).

The fragile X syndrome is the most common cause of familial mental retardation. Genetic counseling and gene isolation are hampered by a lack of DNA markers close to the disease locus. Two somatic cell hybrids that each contain a human X chromosome with a breakpoint close to the fragile X locus have been characterized. A new DNA marker (DXS296) lies between the chromosome breakpoints and is the closest marker to the fragile X locus yet reported. The Hunter syndrome gene, which causes iduronate sulfatase deficiency, is located at the X chromosome breakpoint that is distal to this new marker, thus localizing the Hunter gene distal to the fragile X locus.

Animals↗
PubMed1989

Assignment of anonymous DNA probes to specific intervals of human chromosomes 16 and X.

Anonymous DNA probes mapping to human chromosome 16 and the distal region of the human X chromosome were isolated from a genomic library constructed using lambda EMBL3 and DNA from a mouse/human hybrid. The hybrid cell contained a der(16)t(X;16)(q26;q24) as the only human chromosome. Fifty clones were isolated using total human DNA as a hybridisation probe. Forty six clones contained single copy DNA in addition to the repetitive DNA. Pre-reassociation with sonicated human DNA was used to map these clones by a combination of Southern blot analysis of a hybrid cell panel containing fragments of chromosomes 16 and X and in situ hybridisation. One clone mapped to 16pter----16p13.11, one clone to 16p13.3----16p13.11, four clones to 16p13.3----16p13.13, two clones to 16p13.13----16p13.11, one clone to 16p13.11, seven clones to 16p13.11----16q12 or 16q13, four clones to 16q12 or 16q13, three clones to 16q13----16q22.1, four clones to 16q22.105----16q24, and nineteen clones to Xq26----Xqter. Two clones mapping to 16p13 detected RFLPs. VK5 (D16S94) detected an MspI RFLP, PIC 0.37. VK20 (D16S96) detected a TaqI RFLP, PIC 0.37 and two MspI RFLPs, PIC 0.30 and 0.50. The adult polycystic kidney disease locus (PKD1) has also been assigned to 16p13. The RFLPs described will be of use for genetic counselling and in the isolation of the PKD1 gene. Similarly, the X clones may be used to isolate RFLPs for genetic counselling and the isolation of genes for the many diseases that map to Xq26----qter.

Animals↗
PubMed1989

A skills training approach to smoking prevention among Hispanic youth.

The present study was designed to test the feasibility, acceptability, and effectiveness of a 15-session smoking prevention intervention with a predominantly hispanic (74%) sample of seventh-grade students (N = 471) in eight urban schools in the New York area. The smoking prevention curriculum teaches social resistance skills within the context of a broader intervention promoting general personal and social competence and was implemented in this study by regular classroom teachers. Results of logistic regression analyses provided preliminary evidence of the efficacy of this type of smoking prevention strategy with urban minority youth when implemented with a reasonable degree of fidelity. The significance of these findings is that they provide support for the generalizability of an approach previously found to be effective with white middle-class populations to a predominantly hispanic inner-city population.

Adolescent↗
PubMed1989

Pyridoxal isonicotinoyl hydrazone and analogues. Study of their stability in acidic, neutral and basic aqueous solutions by ultraviolet-visible spectrophotometry.

The ultraviolet-visible absorption spectra of the orally effective iron chelator, pyridoxal isonicotinoly hydrazone (PIH), and three analogues, pyridoxal benzoyl hydrazone (PBH), pyridoxal p-methoxybenzoyl hydrazone (PpMBH) and pyridoxal m-fluorobenzoyl hydrazone (PmFBH) have been measured in aqueous solution with various concentrations of added acid or alkali. Assignment of absorption bands to various molecular species in equilibrium in aqueous solution is made by reference to their acid ionisation constants. All four hydrazones were stable at physiologial pH, but hydrolysed in strongly acidic and basic solutions, resulting in the liberation of pyridoxal and the acid hydrazide. In acidic solutions this resulted in a dramatic decrease in the intensity of absorption at wavelengths of 225 nm and above 300 nm, allowing a quantitative estimate of the degree of acid-catalysed hydrolysis of the ligands. These results indicate that for oral administration the chelator should be administered with calcium carbonate or provided with an enteric coating to minimise acid-catalysed hydrolysis in the stomach. At high pH, base-catalysed hydrolysis occurred, resulting in a decrease in the absorption at a wavelength of 387 nm.

Drug Stability↗
PubMed1989

Iron chelators of the pyridoxal isonicotinoyl hydrazone class. III. Formation constants with calcium(II), magnesium(II) and zinc(II).

Formation constants for the calcium(II), magnesium(II) and zinc(II) complexes of the orally effective iron chelator, pyridoxal isonicotinoyl hydrazone (PIH) and three analogues, pyridoxal benzoyl hydrazone (PBH), pyridoxal p-methoxybenzoyl hydrazone (PpMBH) and pyridoxal m-fluorobenzoyl hydrazone (PmFBH) have been determined by potentiometry at 25 degrees C and I = 0.1 M [KNO3]. The four ligands bind calcium(II) weakly and magnesium(II) only slightly more strongly, as a 1:1 complex which is formed at pH greater than 8. The chelation of zinc(II) for all the ligands studied was greater than that for calcium(II) and magnesium(II), with complexation generally becoming significant at about pH 5. Thus, chelation of zinc(II) but not calcium(II) or magnesium(II) at physiological pH, 7.4 may be expected. Calculated values of the concentration of uncomplexed metal ion indicate that the selectivity of these ligands towards Fe(III) is comparable to that of the clinically used chelator desferrioxamine.

Calcium↗
PubMed1989

Processing of visual syntax in a globally aphasic patient.

A globally aphasic patient was trained on a computerized visual communication system. His ability to comprehend reversible locative prepositional phrases after training was studied and compared with the performance of Broca's aphasics on a similar task. This patient's ability to generalize symbols for actions was also investigated. The results demonstrate our patient's capacity to master a formal visual syntax in the absence of natural language and illustrate how this capacity may be used successfully in a visual communication system. A problem in generalizing symbols for actions is demonstrated, suggesting that certain heuristic and cueing capabilities in the approach may be helpful.

Aphasia↗
PubMed1989

Acalculous cholecystitis in Crohn's disease.

A 15-year-old boy with Crohn's ileocolitis developed marked gallbladder enlargement. Ultrasonographic findings were consistent with acalculous cholecystitis (AAC) or hydrops. At laparotomy a gangrenous gallbladder was found. The diagnostic modalities currently used to distinguish between hydrops, a benign condition generally treated expectantly, and AAC, a potentially life-threatening condition requiring surgical treatment are reviewed. Failure to distinguish between these two conditions with acalculous gallbladder enlargement and similar clinical and radiologic features may have serious consequences.

Acute Disease↗
PubMed1989

Dimensions of assertiveness: differential relationships to substance use in early adolescence.

We tested a multidimensional formulation of assertiveness and substance (tobacco, alcohol, and marijuana) use in 3 metropolitan-area school samples of adolescents aged 12-14 years. Three studies (N = 675, N = 1,430, and N = 5,545) included inner-city and surburban settings and included White, Black, and Hispanic students. Factor analysis of versions of the Gambrill-Richey Assertion Inventory indicated five independent dimensions of assertive behavior. Multiple regression analysis indicated that a dimension of Substance-specific Assertiveness was inversely associated with substance use, whereas dimensions of Social Assertiveness and Dating Assertiveness were positively associated with substance use. A dimension of General Assertiveness was unrelated to substance use. Interaction effects indicated that relations were stronger for girls for Substance and Social Assertiveness and for boys for Dating Assertiveness. Implications of the findings for models of assertive behavior and for design of primary prevention programs are discussed.

Adolescent↗
PubMed1989

The gene for human leukemia inhibitory factor (LIF) maps to 22q12.

The gene for human leukemia inhibitory factor (LIF) has been mapped by Southern analysis of a series of mouse/human somatic cell hybrids and by in situ hybridization to the chromosomes of two normal males and some individuals with chromosomal rearrangements. The gene maps to 22q11-q12.2, between the Philadelphia translocation BCR gene and the breakpoint of the translocation in cell line GM2324 at 22q12.2. From the grain distribution over high resolution chromosome preparations, the most likely location is 22q12.1----q12.2. Southern analysis of DNA from one Ewing sarcoma with t[11;22][q24;q12] showed that the breakpoint on chromosome 22 is more than 15 kb 5' or 8 kb 3' from the LIF gene. The location of the LIF gene indicates that translocations of this gene are unlikely to play a role in myeloid leukemia and myeloproliferative disorders.

Blotting, Southern↗
PubMed1989

Smokeless tobacco use among adolescents: correlates and concurrent predictors.

Seventh grade students (N = 1539) from three regions of New York State were surveyed to determine the prevalence of smokeless tobacco use and its relationship to seven background variables, 13 substance use variables, and 19 psychosocial variables. Significant correlations with smokeless tobacco use were found within each of these variable domains. Concurrent predictors for each domain were determined using logistic regression analysis. The resulting three models were combined in a stepwise fashion in an effort to determine the most complete prediction model. The final model indicated that individuals at the highest risk for using smokeless tobacco were rural males who had smoked more than four cigarettes in their lifetime, were more heavily involved with alcohol, had a lower degree of assertiveness and social anxiety, and had reported eating as a coping response. Implications for prevention are discussed.

Adolescent↗