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Biomedical subjects

L J Harris

Publications and source records attributed to L J Harris.

At least 73 records · Page 4Linked to original sources
PubMed1991

Demographic and risk factors associated with chronic dieting in adolescents.

A comprehensive, school-based survey was administered to 36,320 Minnesota public school students in grades 7 through 12 during the 1987-1988 school year. Self-reported chronic dieting was much higher in girls than in boys (12.1% of all girls vs 2.1% of boys). For girls, the percentage of chronic dieters was significantly less in grades 7 and 8 (7.8%) than in grades 9 and 10 (13.5%) or grades 11 and 12 (14.3%). There were no differences among urban, suburban, or rural youth. Black girls were less likely to diet compared with white girls. Chronic dieters were more likely than other students to report maladaptive weight-loss techniques, such as self-induced vomiting (relative risk, 9.92 for girls and 9.40 for boys), laxative use (relative risk, 7.18 for girls and 11.00 for boys), ipecac use (relative risk, 8.33 for girls and 11.00 for boys), and diuretic use (relative risk, 7.30 for girls and 13.5 for boys). It is suggested that chronic dieting may serve as a screening marker for more severe eating and weight-loss behaviors.

Adolescent↗
PubMed1991

Cerebral control for speech in right-handers and left-handers: an analysis of the views of Paul Broca, his contemporaries, and his successors.

According to several recent historical accounts, Broca (1865a) stated that left-handers are the mirror-reverse of right-handers for cerebral control of speech, with the right hemisphere being dominant in left-handers, and the left hemisphere dominant in right-handers. The same accounts then note Broca's error in light of current evidence that the majority of left-handers are left-dominant for speech just as are nearly all right-handers. Eling (1984) has called such statements misrepresentations of Broca's position and has argued that Broca's analysis actually was more compatible with the current view that there is a disjunction, meaning an absence of an intimate anatomical relationship, between cerebral control for handedness and speech. The current paper looks again at Broca's work, describes the context in which his views were first articulated, and traces the development of the mirror-reversal principle. The conclusion is reached that, judged by a narrow reading of the 1865 paper, Broca's views could indeed be construed as an anticipation of the modern disjunction principle. However, judged by a broader reading, by consideration of his other writing, and in the context of the philosophical and scientific tradition that shaped his work, it is suggested that it was the mirror-reversal principle to which Broca was actually disposed.

Cerebral Cortex↗
PubMed1991

Genetic analysis of B-Peru, a regulatory gene in maize.

The B locus in maize is required for the accumulation of anthocyanin pigments. Numerous B alleles have been described: each determines a particular pattern of pigment synthesis with respect to the tissues that are pigmented and the time during development that pigment synthesis begins. We report here a genetic analysis of one B allele, B-Peru, which regulates synthesis of pigments in both kernel and plant tissues. We used stocks with active Mutator transposable elements to produce eight mutations in B-Peru. All eight alter pigment synthesis in all the kernel and plant tissues pigmented by B-Peru, suggesting that each mutation has disrupted a region of the gene required for expression in all tissues. Six of the mutations cause a colorless phenotype, while two cause a reduction in pigment in both kernel and plant tissues. Four of the mutations are unstable, and four are stable upon self-pollination. Multiple independent revertants were isolated from each unstable allele. DNA blot analysis demonstrated that all eight mutants are the result of insertions within an approximately 5-kb region that encodes the B-Peru transcript. One of the four unstable alleles contains a Mu element, Mu1.7. Two others contain insertions related to the Spm family of transposable elements. Thus, our Mutator stocks also contained active transposable elements from the unrelated Spm family. Our experiments suggest that the B-Peru allele is not complex, but contains a single coding region that regulates pigment synthesis in multiple tissues.

Alleles↗
PubMed1991

Evolutionarily conserved regions in Caenorhabditis transposable elements deduced by sequence comparison.

In this paper we present the sequence of an intact Caenorhabditis briggsae transposable element, Tcb2. Tcb2 is 1606 base pairs in length and contains 80 base pair imperfect terminal repeats and a single open reading frame. We have identified blocks of T-rich repeats in the regions 150-200 and 1421-1476 of this element which are conserved in the Caenorhabditis elegans element Tc1. The sequence conservation of these regions in elements from different Caenorhabditis species suggests that they are of functional importance. A single open reading frame corresponding to the major open reading frame of Tc1 is conserved among Tc1, Tcb1, and Tcb2. Comparison of the first 550 nucleotides of the sequence among the three elements has allowed the evaluation of a model proposing an extension of the major open reading frame. Our data support the suggestion that Tc1 is capable of producing a 335 amino acid protein. A comparison of the sequence coding for the amino and carboxy termini of the 273 amino acid transposase from Caenorhabditis Tc1-like elements and Drosophila HB1 showed different amounts of divergence for each of these regions, indicating that the two functional domains have undergone different amounts of selection. Our data are not compatible with the proposal that Tc1-related sequences have been acquired via horizontal transmission. The divergence of Tc1 from the two C. briggsae elements, Tcb1 and Tcb2, indicated that all three elements have been diverging from each other for approximately the same amount of time as the genomes of the two species.

Amino Acid Sequence↗
PubMed1991

Sternal wound infections and use of internal mammary artery grafts.

Previous studies have provided conflicting evidence as to whether an increased risk of mediastinitis is associated with use of the internal mammary artery as a coronary bypass graft. In this study the effects of internal mammary artery grafts on wound complications were analyzed in a prospective, nonrandomized fashion. At New York University Medical Center from January 1985 through May 1988, 2356 patients underwent isolated coronary revascularization. Among these patients 1394 received one or more internal mammary artery grafts (group I) and 962 had vein grafts only (group II). Group I had a mean age of 59.5 years versus 67.7 years in group II; diabetes was equally present in both groups (22.7% versus 24.7%). Operative mortality rate was 1.3% in group I and 5.6% in group II. Sternal infection was significantly more prevalent in group I (2.2%, 31/1394) than in group II (0.8%, 8/962). Multivariate analysis revealed that aortic crossclamp time, use of a single internal mammary artery graft, use of a double mammary graft, and diabetes were associated with increased risk of sternal infection. The use of bilateral internal mammary artery grafting doubled the odds ratio of the risk compared with use of a single mammary graft, and the combination of diabetes and double internal mammary artery grafts increased the odds ratio 13.9-fold. Patients with an internal mammary artery graft who had sternal infection had a longer period of hospitalization than patients without a mammary artery graft who had sternal infection. We conclude that the risk of sternal infection is increased by the use of an internal mammary artery graft, especially use of double mammary grafts in the presence of diabetes.

Aged↗
PubMed1990

Isolation and sequence analysis of Caenorhabditis briggsae repetitive elements related to the Caenorhabditis elegans transposon Tc1.

We have identified two repetitive element families in the genome of the nematode Caenorhabditis briggsae with extensive sequence identity to the Caenorhabditis elegans transposable element Tc1. Five members each of the TCb1 (previously known as Barney) and TCb2 families were isolated by hybridization to a Tc1 probe. Tc1-hybridizing repetitive elements were grouped into either the TCb1 or TCb2 family based on cross-hybridization intensities among the C. briggsae elements. The genomic copy number of the TCb1 family is 15 and the TCb2 family copy number is 33 in the C. briggsae strain G16. The two transposable element families show numerous genomic hybridization pattern differences between two C. briggsae strains, suggestive of transpositional activity. Two members of the TCb1 family, TCb1#5 and TCb1#10, were sequenced. Each of these two elements had suffered an independent single large deletion. TCb1#5 had a 627-bp internal deletion and TCb1#10 had lost 316 bp of one end. The two sequenced TCb1 elements were highly conserved over the sequences they shared. A 1616-bp composite TCb1 element was constructed from TCb1#5 and TCb1#10. The composite TCb1 element has 80-bp terminal inverted repeats with three nucleotide mismatches and two open reading frames (ORFs) on opposite strands. TCb1 and the 1610-bp Tc1 share 58% overall nucleotide sequence identity, and the greatest similarity occurs in their ORF1 and inverted repeat termini.

Animals↗
PubMed1990

Multiple aneurysms of the coronary arteries in a patient with systemic aneurysmal disease.

A case of multiple coronary artery aneurysms in a patient with an abdominal aortic aneurysm and bilateral popliteal artery aneurysms is reported. As diagnosis and treatment of coronary artery disease become more aggressive, a higher incidence of detection of coronary artery aneurysms in conjunction with peripheral vascular lesions is likely. The role of coronary sinus cardioplegia in minimizing the risk of embolization from the coronary aneurysms during surgical repair is emphasized.

Aged↗
PubMed1990

Mixed speech dominance in the Intracarotid Sodium Amytal Procedure: validity and criteria issues.

An international survey was conducted of 55 epilepsy surgery programs (from 10 countries) that conduct the Intracarotid Sodium Amytal Procedure (IAP). Respondents reported large differences in the prevalence of mixed speech dominance (MSD) in their patient populations. These differences are shown to be due in part to disagreement about the criteria for the demonstration of speech production from the non-speech-dominant hemisphere. The disagreement may be related to differences in the administration and interpretation of the IAP as well as the validity of the construct of MSD. The prevalence of MSD in various patient populations cannot be determined until standard procedures for the administration of the IAP are adopted and until the validity of criteria for MSD is demonstrated. Clinical implications of these results are discussed.

Amobarbital↗
PubMed1989

Structural analysis of Tc1 elements in Caenorhabditis elegans var. Bristol (strain N2).

The transposable element Tc1 in the genome of Caenorhabditis elegans var. Bristol strain N2 is very stable. In order to investigate possible causes of Tc1 immobility in this strain 17 individual isolates have been cloned and characterized with regard to their structure and genomic environment. Ten of 16 elements examined had identical restriction maps, and at least 1 of these (#7) showed a high level of somatic excision. Two of the elements had altered restriction sites, 2 had different internal deletions of about 700 bp, 1 had an 89-bp terminal deletion, and 1 a 54-bp insertion. When DNA sequences flanking the N2 Tc1 elements were used as probes in genomic hybridizations, it was found that most N2 elements are located in regions of repetitive DNA. Furthermore when hybridizations to DNA from N2 and var. Bergerac strain B0 were performed, a major band of the same size was observed in both strains. Two flanking sequences identified strain polymorphic sites hP2(IV) and hP3(IV). In at least one of these cases, a rearranged Tc1 was present in the B0 strain at the same location. The fact that all or most of the Tc1 elements are in the same location in N2 and B0 adds support to the hypothesis that the high copy number B0 strain arose from amplification of Tc1 copies in a N2-like strain. The N2 Tc1 elements are highly conserved; however, intact elements had fewer nucleotide changes than the rearranged elements. These results may indicate that the intact Tc1 elements in N2 are functionally active and subject to selective pressure.

Animals↗
PubMed1989

Hand preference in gestures and signs in the deaf and hearing: some notes on early evidence and theory.

Research has shown that when persons with normal hearing accompany their speech with gestures, right-handers use more right-hand gestures, and left-handers use more left-hand gestures, although to a lesser extent (D. Kimura, 1973a, 1973b, Neuropsychologia, 11, 45-50, 51-55.). Comparable differences have been found in deaf persons when signing, with the direction of hand dominance for signing in both right- and left-handers corresponding to that for nonlinguistic actions (J. Vaid, D. Schemenauer, U. Bellugi, & H. Poizner, 1984, Hand dominance in a visual-gesture language. Paper presented at BABBLE, March, Niagara Falls, Ontario, Canada). In this paper, I recount early theories and observational data about hand dominance for gesture and signing, both in the hearing and the deaf. Several of these early theories and observations anticipate current work and also suggest new avenues for investigation.

Deafness↗
PubMed1989

Footedness in parrots: three centuries of research, theory, and mere surmise.

In contemporary debates about laterality in animals, the parrot (Psittaciformes) is often cited as an exemplar--possibly unique--of laterality in limb function at the population level comparable in kind and strength to handedness in man. This conclusion rests on just two reports (Friedman & Davis, 1938; Rogers, 1980) that most species of parrots are left-footed, that is, that they preferentially perch on the right foot and hold food with the left. In fact, speculation about and scientific study of laterality in parrots go well beyond these two investigations. The question itself dates from at least the 17th century, after which, beginning in the 1860s, it became the subject of broad interest and debate. In our own time, it also has continued to occupy the attention of at least a small number of ornithologists and field biologists whose work, like that of their predecessors, is not cited in the current neuropsychological literature on this topic. To fill out the historical as well as contemporary record for consideration by neuropsychologists today, these other observations and theoretical analyses are reviewed, and new questions about laterality in parrots raised by this work are presented.

Animals↗
PubMed1989

Ten-year operative experience with 165 aneurysms of the ascending aorta and aortic arch.

Results of surgery in 165 patients with aneurysms of the ascending aorta and aortic arch during 1978-1988 were analyzed retrospectively. Etiology included 29% dissection, 22% atherosclerosis, 22% cystic-medial necrosis, and 27% other causes. Concomitant procedures on the aortic valve were performed in 65% of patients (valvular replacement in 37%, valve-conduit in 23%, and valvular resuspension in 5%), and 13% underwent concomitant coronary artery bypass surgery. Major changes in our operative technique for such aneurysms have been introduced during the last 5 years, especially use of a continuous suture-graft-inclusion technique in 99% of patients, use of circulatory arrest in 59%, and use of an open hemiarch repair in 32%. Hospital mortality dropped from 17.9% during the first 5 years of the study period to 12.3% in the last 5 years despite increasing complexity of the cases encountered. Operative mortality was 7.6% for ascending aortic aneurysmal repair; 5.3% for valve-conduit procedure; 8.8% for open hemiarch repair; and 30.8% for repair of extensive aneurysms involving the aortic arch and significant portions of the descending aorta. Multivariate analysis showed that, of the variables examined, significant predictors of increased operative risk were age (p less than 0.05) and extension of an ascending aortic aneurysm to the descending aorta or involvement of the aortic arch (p less than 0.001). The incidence of stroke was 2.4%, with only one stroke since 1983 despite more extensive use of circulatory arrest since that time. Follow-up was 94% complete, with a mean (+/- SD) follow-up interval of 28 +/- 24 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Food habits and dietary change of Southeast Asian refugee families living in the United States.

Food habits and changes in food consumption patterns were assessed among 60 Southeast Asian refugee families (Cambodian and Hmong) living in the United States. With the use of a structured interview schedule, in-home interviews were conducted by a Hmong or a Cambodian bilingual staff person with the adult having primary responsibility for family meal preparation. Results indicated that while food buying practices have changed drastically in the U.S., Southeast Asian refugee families have maintained strong ties to their native foods and traditional diets. In the U.S., as in Southeast Asia, rice remains the staple food in their diet. High status foods in Cambodia and Laos, such as fruits, meats, and soft drinks, remain highly preferred foods in the U.S. and are consumed frequently. Although most adults prefer eating their native foods, their children prefer both American and native foods. Thirty percent of the adolescents in the home had major responsibility for evening meal preparation.

Adolescent↗
PubMed1988

Sequence identity between an inverted repeat family of transposable elements in Drosophila and Caenorhabditis.

The Tc1-like transposable elements, originally described in Caenorhabditis elegans, have a much wider phylogenetic distribution than previously thought. In this paper, we demonstrate that Tc1 shares sequence identity in its open reading frame and terminal repeats with a new transposable element Barney (also known as TCb1-Transposon Caenorhabditis briggsae 1). Barney was detected and isolated by Tc1 hybridization from the closely related nematode species, Caenorhabditis briggsae. The conserved open reading frames of Tc1 and Barney share identity with a structurally similar family of elements named HB found in Drosophila melanogaster, after the introduction of 3 small centrally located deletions in HB1. These reading frames would code for proteins with 30% amino acid identity (42% when conservative changes are included). Tc1, Barney and HB1 contain highly conserved blocks of amino acids which are likely to be in the functional domains of the putative transposase.

Amino Acid Sequence↗
PubMed1988

The relationship between cerebral lateralization and cognitive ability: suggested criteria for empirical tests.

Many recent investigations in cognitive neuropsychology have been devoted to a fundamental question: are individual differences in cerebral lateralization reliably associated with differences in cognitive ability? The results have been highly inconsistent and inconclusive, with some studies showing a relationship, others not. We propose that research on this question has been hampered by inadequate clarification of the criteria required for a proper test. We suggest what these criteria should be, and, for purposes of illustration, we evaluate representative tests of the lateralization--cognition hypothesis in light of these criteria. We conclude that studies that meet our criteria lend at least a modest measure of support for the hypothesis.

Cognition↗
PubMed1988

Food preferences, beliefs, and practices of Southeast Asian refugee adolescents.

Food preferences, beliefs, and practices were assessed among 207 Southeast Asian refugee high school students, all of whom had been in the U.S. five years or less. Questionnaires typed both in English as well as their native language of either Cambodian, Vietnamese, or Hmong, were administered to all students in a classroom setting. Results indicated Southeast Asian refugee youth have maintained strong ties to their native foods and traditional meal patterns. In the U.S., as in Southeast Asia, rice remains the staple food in their diet. High status foods in Southeast Asia such as fruits, meats, and soft drinks remain highly preferred in the U.S. While milk is well-liked, cheese remains a strongly disliked food item. Fruits and vegetables are frequently consumed. Nutritionally weak American foods such as candy bars, cake, and potato chips are not consumed frequently. However, soft drinks are consumed daily by almost one-third of the students. Breakfast was missed by almost 60% of females and 37% of males. Forty-five percent of the youth reported they had primary responsibility for evening meal preparation.

Adolescent↗