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Biomedical subjects

R Ehrlich

Publications and source records attributed to R Ehrlich.

At least 235 records · Page 13Linked to original sources
PubMed1987

Tissue-specific expression and structure of a divergent member of a class I MHC gene family.

The class I gene family of the major histocompatibility complex (MHC) of the miniature swine (SLA) contains seven members. Six of these are highly homologous, whereas the seventh, PD6, is only distantly related. A genomic clone containing PD6 has been isolated and characterized. The PD6 SLA gene, although only 55% homologous to the other SLA class I sequences, is still a member of the family; its size and exon/intron organization are similar to other class I genes. When aligned with other SLA genes, exons 1 to 6 of PD6 have open reading frames; exon 7 contains a termination codon. PD6 is transcribed in transfected mouse L cells where its expression is enhanced by interferon. In vivo expression of PD6 is observed in a variety of tissues, with the highest levels in mature lymphoid tissues. Peripheral T cells contain high levels of PD6-specific RNA relative to B cells, whereas no PD6 transcripts are detectable in thymocytes.

Amino Acid Sequence↗
PubMed1987

Dynamic and structural characterisation of multiple steps during complex formation between E. coli RNA polymerase and the tetR promoter from pSC101.

Kinetic, functional and structural studies of the recognition of the tetR promoter from pSC101 by E. coli RNA polymerase allowed the characterization of several steps in the specific complex formation and transcription initiation process. First, enzyme and DNA enter in a short life-time complex. An isomerization will convert this unstable complex into a closed stable one where RNA polymerase is tightly attached without establishing stable chemical contacts with the bases. In the next step, stable close contacts appear between both macromolecules involving mainly the downstream part of the promoter. A further isomerization will lead to an open complex where DNA is locally melted and the system is able to initiate transcription. This latter process is accompanied by changes in the upstream part of the promoter. Finally, in vitro transcription assays showed that the position of the major transcription start sites depends on temperature. From the reported results, it appears that the recognition event is a sequential process where different structural elements of the promoter, that can be located apart in the sequence, are involved in a concerted manner in each stage.

Cytosine↗
PubMed1987

Echocardiographic estimate of left atrial pressure in children.

Echocardiographic estimates of left atrial pressure using the Q-MVC/AVC-E ratio were obtained from 21 patients in the early postoperative period and compared to simultaneously recorded mean left atrial pressure. A good correlation was obtained between mean left atrial pressure and the Q-MVC/AVC-E ratio (r = 0.81, p less than 0.001) with a regression equation of: left atrial pressure = 11.09 (Q-MVC/AVC-E) + 0.84. The present data compared to those of previous investigators reveal that, although there are quantitative differences between each of the studies, the correlation coefficient of each study is good. Echocardiography provides a useful noninvasive estimate the left atrial pressure; however, each laboratory must establish its own normals.

Blood Pressure↗
PubMed1987

Structure and expression of class I MHC genes in the miniature swine.

The genome of the miniature swine, unlike other species, contains a relatively small class I MHC gene family, consisting of only seven members. This provides an excellent system in which to identify and characterize the regulatory mechanisms which operate to both coordinately and differentially regulate the expression of a multi-gene family. The structure of class I SLA genes, like other class I genes, consists of eight exons encoding a leader sequence, three extracytoplasmic domains, a transmembrane domain and intracytoplasmic domains. Despite the common structure, two sub-families of class I genes can be distinguished within the SLA family. One, containing the closely related PD1 and PD14 genes, encodes the classical transplantation antigens. Another contains the highly divergent PD6; the functions of the products of this subfamily, if any, are not known. The class I SLA genes share some common regulatory mechanisms, as evidenced by the fact that all three genes analyzed are transcribed in mouse L cells. Furthermore, interferon treatment of transfected mouse L cells enhances expression of all three genes. Both PD1 and PD6 are transcribed in vivo, where the highest levels of expression are observed in lymphoid tissues. Superimposed on the common patterns of class I gene expression are distinct ones, as evidenced by the findings that PD1 is preferentially expressed in B cells, whereas PD6 is preferentially expressed in T cells. These differences may reflect the extensive divergence of the 5' flanking sequences of these genes. Future studies will be aimed at elucidating the precise molecular interactions and mechanisms which give rise to the observed differential expression.

Animals↗
PubMed1987

Intellectual outcome in children with fetal hypothyroidism.

Eighty children with congenital hypothyroidism detected by newborn screening were grouped for presence of fetal hypothyroidism using skeletal maturity at the time of diagnosis as the index. Forty-five children with bone age less than 36 weeks were assigned to the delayed group; 35 with bone age 37 weeks to term were assigned to the nondelayed group. Although most children with athyrosis were found in the delayed group, the groups did not differ in birth weight, hormone levels, or family background. Assessments of intellectual and behavioral characteristics at 1, 2, 3, 4, and 5 years of age revealed that, although children in the delayed group performed within the normal range, their scores were significantly lower than those of the nondelayed group from age 2 years on. Perceptual-motor, visuospatial, and language areas were most affected. There were no differences in behavior or temperamental characteristics.

Age Determination by Skeleton↗
PubMed1987

Ethanol: an enhancer of major histocompatibility complex antigen expression.

Ethanol enhances expression of cell surface class I major histocompatibility complex (MHC) antigens in a variety of cell lines; up to an eightfold increase is observed in an embryonic cell line. In ethanol-treated L cells, increased cell surface expression of MHC antigens occurs with a concomitant increase in steady-state RNA levels. This effect is promoter dependent and restricted, because not all gene products are elevated. The effective ethanol concentration (1%) is physiologically attainable, leading to speculations about the role of elevated MHC antigens in alcohol-related diseases.

Animals↗
PubMed1987

Fallout sheltering: is it feasible?

The feasibility of sheltering the U.S. population from fallout resulting from a large-scale nuclear attack is assessed using a mathematical model. The model is used to calculate the reduction in cumulative dose received by a sheltered survivor, as a function of five adjustable parameters. Three time periods are postulated: time in the shelter, a transition period during which time out of the shelter increases and a final period in which half the time is spent outside the shelter. The parameters are varied independently, and the resulting dose reduction factor is compared with what seems to be necessary for survival in different regions of the country under the postulated attack. Another model developed by K.S. Gant and C.V. Chester is compared with this one. Similarities and differences are pointed out, and where possible the results of the two are checked for compatibility. An important question addressed in this paper is whether under the conditions of a large-scale nuclear attack sheltering a relatively unprepared population is at all feasible. Sensitivity tests of the various parameters in our model show that relatively low protection factor areas such as basements or inner rooms already existing in homes or other buildings could quite adequately serve as shelters for most of the area of the contiguous United States. Furthermore, continuous stays in these shelters of more than three weeks do not seem to be necessary for these large parts of the United States.

Humans↗
PubMed1987

Behaviour problems in children with diabetes as a function of sex and age of onset of disease.

Twenty-seven children with early onset (less than or equal to 3 years) diabetes (EOD), 24 with late onset (greater than or equal to 4 years) diabetes (LOD) and 30 sibling controls were compared on measures of psychosocial adjustment. These included parent rating scales of behaviour problems and temperament; direct measures of self-esteem, body image and school achievement; and indices of diabetic control. Results indicated that LOD boys showed increased incidence of behaviour problems, 83% of whom could be assigned a diagnostic classification and more distortions of body image. The results were not related to any indices of diabetic control.

Adolescent↗