Search PubMed⌕ Search

Biomedical subjects

E C Jenkins

Publications and source records attributed to E C Jenkins.

At least 37 records · Page 2Linked to original sources
PubMed1996

Tissue differences in fragile X mosaics: mosaicism in blood cells may differ greatly from skin.

The fragile X mutation is diagnosed from the structure of the FMR1 gene in blood cell DNA. An estimated 12 to 41% of affected males are mosaics who carry both a "full mutation" allele from which there is no gene expression and a "premutation" allele which has normal gene expression. We compared the DNA in blood cells and skin fibroblasts from four mosaic fragile X males to see if there was a difference in the relative amounts of premutation and full mutation alleles within the tissues of these individuals. Two of these males showed striking differences in the ratio of premutation to full mutation in different tissues while the other two showed only slight differences. These observations conform with the widely accepted hypothesis that the fragile X CGG repeat is unstable in somatic tissue during early embryogenesis. Accordingly, the mosaicism in brain and skin, which are both ectodermal in origin, may be similar to each other but different from blood which is not ectodermal in origin. Thus, the ratio of full mutation to premutation allele in skin fibroblasts might be a better indicator of psychological impairment than the ratio in blood cells.

Blood Cells↗
PubMed1995

Light and electron microscopic immunocytochemical localization of two major proteins in garlic bulb.

Garlic is known as a potent spice and a medicine with broad therapeutic properties ranging from antibacterial to anticancer, antidiabetic, and anticoagulant. Two major proteins of 40 KD and 14 KD constituting approximately 96% of total garlic proteins have been recently purified at our Institute. This immunocytochemical and ultrastructural study revealed that the 40 KD protein was localized in the parenchyma sheath cells (PSC) of garlic bulbs, whereas the 14 KD protein was present in the cortical cells (CC). Immunogold electron microscopy study indicated that the 40 KD protein was specifically localized in the globular granules of the cytoplasmic area of PSC. Each globular granule was amorphous and homogenous with membrane limiting its outermost layer. The yellowish color of PSC in freshly cut slices of garlic bulb suggested that PSC may have sulfur-containing compounds such as allicin, the primary contributor of the pungency and medicinal properties of garlic. Ellman's reagent test quantitatively revealed that there were 17.8 n moles sulfhydryl (SH)/ml of 40 KD garlic protein. Microtubule tubulin in mitotic figures from PHA-stimulated human short-term whole blood cultures reacted strongly with antitubulin antibody but reacted negatively with anti-40 KD garlic protein antibodies and therefore was not related to the 40 KD garlic protein immunocytochemically.

Antibodies, Monoclonal↗
PubMed1994

Fragile X induction systems in CVS cultures: effect on cytogenetic, PCR, and genomic Southern Blot DNA analyses of the FMR-1 gene.

Low fragile X frequencies have been commonly observed in chorionic villus sample (CVS) cultures, compared to subsequent analysis in whole blood or products of conception (POC). To investigate possible mechanisms for this effect, CVS cultures from a previously identified fragile X positive male, were restudied and compared to subsequent POC cultures from lung, muscle, skin, and thymus. Cultures were exposed, for the last 24 hours before harvesting, to FUdR, excess thymidine, and a combination of both. For CVS, only those cultures that were exposed to a combination of FUdR and excess thymidine showed positive cytogenetic findings (1/90 or 1.1%), agreeing with our original positive cytogenetic results (2/86 or 2.3%) for cultures exposed to excess thymidine. Fragile X frequencies in the POC tissues from this fetus increased to an average of 14%. PCR analyses showed full mutations (> 200 CGG repeats) in uninduced CVS cultures but induced cultures exhibited apparently smaller sizes in the range of 120-180 repeats. The results showed variability. In one instance, the banding pattern from one of the uninduced cultures was similar to the results where cultures were exposed to a double induction system. When PCR analyses were conducted on induced POC cultures, full mutations were observed in virtually all samples. Southern blot genomic analysis using probe StB12.3 showed an unmethylated full mutation in CVS cultures. Southern blot patterns from cultures of muscle revealed size variations of DNA bands in the premutation range representing unmethylated DNA as well as methylated full mutations. Finally, variations were also observed in lung and skin cultures, compared to CVS and muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Southern↗
PubMed1994

Effect of aluminum chloride on mitogenesis, mitosis, and cell cycle in human short-term whole blood cultures: lower concentrations enhance mitosis.

Aluminum, the third most common element in the earth's crust (second to oxygen and silicon) and recently suspected by some investigators to be implicated in Alzheimer disease etiology, has been studied in relation to its effect on mitogenesis, mitosis, and cell cycle. We have observed that 2-4 mM concentrations of AlCl3 have decreased the number of cells that undergo mitogenesis (PHA-induced blast transformation) and mitosis in human short term whole blood cultures. We have also shown that the rate of the cell cycle was slowed down, i.e., cell cycle time was increased in the presence of AlCl3. Also, we have demonstrated a reversible effect on aluminum-induced reduced mitotic index in long-term EBV-transformed lymphoblastoid cultures. Although safeguards such as limiting aluminum serum concentrations have been recommended to protect individuals undergoing dialysis, it should be realized that concentration accumulations of aluminum may increase over chronic exposures. Accordingly, if the number of cells stimulated by PHA is reduced in the presence of AlCl3, there may be a reduction of immune competence, since the degree of PHA stimulation has been used as an indicator of immune response. Similar reductions in mitotic index could affect every tissue involved with cell division. Although it may not be the same for higher concentrations, from our results, we have also shown that decreased mitotic rates were reversible in long-term EBV-transformed lymphoblastoid cultures. Increased numbers of mitoses were observed in human short-term whole blood cultures that were exposed to 2 microM concentrations of aluminum chloride.(ABSTRACT TRUNCATED AT 250 WORDS)

Aluminum Chloride↗
PubMed1994

Characterization of a strain of cerebral endothelial cells derived from goat brain which retain their differentiated traits after long-term passage.

A strain of cerebral endothelial cells was established from isolated cortical microvessels of caprine brain. These cells, which are referred to as EC1 cells, can be routinely subcultured to 32 passages without the loss of differentiated morphologic and immunologic traits. The ability to routinely subculture EC1 cells is an important asset, given that isolated cerebral endothelial cells in mammals generally lose their differentiated traits after only 2 to 3 passages. EC1 cells were shown to contain Factor VIII-related antigen, which is a specific marker for cells of endothelial origin. EC1 cells morphologically demonstrated a scarcity of pinocytotic vesicles on their apical surfaces, a lack of trans-cytoplasmic vesicles, and the ability to form in culture confluent monolayers with tight junctional complexes. Therefore, EC1 cells possess specific antigenic and ultrastructural features which classify them as being small vessel endothelial cells of the blood-brain barrier type. Cytogenetic evaluation of EC1 cells demonstrated a normal female goat 60,XX karyotype and confirmed the apparent non-transformed nature of EC1 cells due to the lack of chromosome abnormalities or rearrangements. Using scanning electron microscopy, EC1 cells were also shown to form confluent monolayers on mixed nitrocellulose filters, a feature that will enable the development of an in vitro system to study trans-endothelial transport. Given that EC1 cells are readily subcultured and grow well on nitrocellulose filters, and that they resemble cerebral endothelium in vivo, it seems evident that EC1 cells can be used as a versatile model for the study of blood-brain barrier function, regulation, and pathology.

Animals↗
PubMed1993

Rapid fragile X carrier screening and prenatal diagnosis using a nonradioactive PCR test.

OBJECTIVE: To develop a rapid, nonradioactive test using the polymerase chain reaction (PCR) capable of detecting full fragile X mutations, premutations, and resolving normal alleles and to apply this to prenatal diagnosis and carrier screening of pregnant women at risk for fragile X carrier status. DESIGN: Prenatal and blood sample PCR analysis with confirmation by direct Southern blotting and cytogenetic techniques. SETTING: Samples sent to a DNA diagnostic research laboratory at a tertiary referral center. PARTICIPANTS: Pregnant women with a family history of undiagnosed mental retardation or known fragile X syndrome and controls. RESULTS: A rapid, nonradioactive PCR screening protocol for the fragile X mental retardation-1 gene for both normal and mutant alleles was developed. Analysis of 570 control X chromosomes showed a modal number of 30 CGG repeats (range, 12 to 52 repeats) and a calculated heterozygosity of approximately 80%. No excess of homozygosity was found, indicating the test was accurate for normal allele resolution. In addition, 150 unrelated pregnant women were screened. Within known fragile X families, five of 20 pregnant women were diagnosed as carriers. Two new fragile X families were diagnosed among relatives of 130 females with family histories of undiagnosed mental retardation, although no carriers were identified. Prenatal PCR testing of 28 carriers accurately detected nine fetuses with full mutations. CONCLUSIONS: This rapid, nonradioactive PCR protocol allows accurate resolution of normal alleles as well as simultaneous detection of carrier alleles and full mutations. With this approach, efficient screening of pregnant women at risk for fragile X carrier status, subsequent genetic counseling of identified carriers, and reliable prenatal diagnosis can be offered.

Base Sequence↗
PubMed1993

Cytogenetic and molecular identification of a de novo direct duplication of the long arm of chromosome 4(q21.3-->q31.3).

We report on a 3-year-old boy with moderate developmental retardation, microcephaly, and malformations of ears, lids, mouth, and thumbs. Cytogenetic analysis demonstrated a direct duplication of chromosome subregion 4(q21.3-->q31.3). Confirmation of this specific rearrangement was performed by fluorescent in situ hybridization (FISH) with a chromosome painting probe and by means of quantitative Southern hybridization with DNA probes localized within the chromosome 4 region presumed to be duplicated.

Abnormalities, Multiple↗
PubMed1992

Proposed guidelines for diagnosis of chromosome mosaicism in amniocytes based on data derived from chromosome mosaicism and pseudomosaicism studies.

Currently, accepted protocol which has been developed at the Prenatal Diagnosis Laboratory of New York City (PDL) requires that when a chromosome abnormality is found in one or more cells in one flask, another 20-40 cells must be examined from one or two additional flasks. Chromosome mosaicism is diagnosed only when an identical abnormality is detected in cells from two or more flasks. In a recent PDL series of 12,000 cases studied according to this protocol, we diagnosed 801 cases (6.68 per cent) of single-cell pseudomosaicism (SCPM), 126 cases (1.05 per cent) of multiple-cell pseudomosaicism (MCPM), and 24 cases (0.2 per cent) of true mosaicism. Pseudomosaicism (PM) involving a structural abnormality was a frequent finding (2/3 of SCPM and 3/5 of MCPM), with an unbalanced structural abnormality in 55 per cent of SCPM and 24 per cent of MCPM. We also reviewed all true mosaic cases (a total of 50) diagnosed in the first 22,000 PDL cases. Of these 50 cases, 23 were sex chromosome mosaics and 27 had autosomal mosaicism; 48 cases had numerical abnormalities and two had structural abnormalities. Twenty-five cases of mosaicism were diagnosed in the first 20 cells from two flasks, i.e., without additional work-up, whereas the other 25 cases required extensive work-up to establish a diagnosis (12 needed additional cell counts from the initial two culture flasks; 13 required harvesting a third flask for cell analysis). Our data plus review of other available data led us to conclude that rigorous efforts to diagnose true mosaicism have little impact in many instances, and therefore are not cost-effective. On the basis of all available data, a work-up for potential mosaicism involving a sex chromosome aneuploidy or structural abnormality should have less priority than a work-up for a common viable autosomal trisomy. We recommend revised guidelines for dealing with (1) a numerical versus a structural abnormality and (2) an autosomal versus a sex chromosome numerical aneuploidy. Emphasis should be placed on autosomes known to be associated with phenotypic abnormalities. These new guidelines, which cover both flask and in situ methods, should result in more effective prenatal cytogenetic diagnosis and reduced patient anxiety.

Amniocentesis↗
PubMed1992

Reassessment of a chromosome 12q+ marker by fluorescent in situ hybridization (FISH).

We present a case previously described by Jenkins et al. (1983) as atypical Down syndrome (DS). The initial diagnosis was first made on the basis of phenotypic and cytogenetic data. This analysis was supported by studies of superoxide dismutase (SOD1) activity that maps to band 21q22.1. Results from phenotypic, chromosome banding and SOD1 studies suggested a karyotype of 46,XX,-12,+t(12pter to 12qter::21q21 to 21q22.?2). Using fluorescent in situ hybridization (FISH) for chromosome painting with DNA libraries derived from sorted human chromosomes to stain selectively the chromosomes No. 21 and No. 12, we demonstrate that the marker chromosome 12q+ has no chromosome 21 content but it is derived from chromosome 12.

Abnormalities, Multiple↗
PubMed1991

Why are autism and the fragile-X syndrome associated? Conceptual and methodological issues.

Investigations of the association between autism and the fragile-X syndrome have yielded conflicting results with some studies indicating a strong correlation and others indicating no relation between the disorders. In this paper, we review the relevant research on this controversy and discuss the conceptual and methodological problems involved in such an inquiry. We conclude that autism and fragile X are associated and that this relation will prove fruitful in understanding the role of the X chromosome in a variety of behavior disorders and in unraveling various theoretical accounts on the etiology of autism.

Autistic Disorder↗
PubMed1990

Study of spindle microtubule reassembly in cells from Alzheimer and Down syndrome patients following exposure to colcemid.

Numerous intraneuronal neurofibrillary tangles and senile (neuritic) plaques are the two characteristic lesions in Alzheimer disease (AD) and adult Down syndrome (DS). Evidence indicates that microtubule assembly is impaired in AD. We studied spindle microtubule repolymerization rates in EBV-transformed lymphoblasts from AD, DS, and control individuals after colcemid exposure. The distinctive arrangement of microtubules in spindle and its size make this structure an obvious choice for study. Recovery trends in the three patient groups differed significantly; in particular, the controls showed an earlier appearance of intact spindle microtubules than AD. Other researchers found similar results using AD fibroblasts. The results from the DS cells were inconsistent and difficult to interpret. It is unclear how the AD microtubules differ from controls, or whether a relationship exists between the altered microtubule repolymerization kinetics observed in this study and the presence of neurofibrillary tangles in AD patients. A difference in repolymerization rates can be the basis for a diagnostic test for AD if it can be verified.

Alzheimer Disease↗
PubMed1990

Progress toward an internal control system for fragile-X induction by 5-fluorodeoxyuridine in whole-blood cultures.

We have been attempting to develop a consistently reliable internal control to assure the effectiveness of the 5-fluorodeoxyuridine (FUdR) fragile-X [fra(X)] induction system. We carried out a systematic study of whole-blood specimens cultured from 56 individuals from two different laboratories. An analysis of nearly 9,000 cells demonstrated: (1) the importance of establishing baseline levels of fragile sites in each laboratory, and (2) that a combination of common fragile sites (different for each laboratory) could serve as a consistently reliable indicator of the effectiveness of the FUdR fra(X) induction system. It was suggested that a non-FUdR culture(s) should be incorporated into a laboratory's fra(X)-screening protocol, so that if there are any doubts about the effectiveness of the FUdR system a comparison to background or spontaneously occurring fragile sites can be made within the laboratory. Repeat cultures are recommended where no increase in common fragile-site frequency is observed in the FUdR induction system, and where fra(X) was strongly suspected but not found. In addition, the necessity of using more than one fra(X) induction system in whole-blood cultures was demonstrated, including the effectiveness of an FUdR/excess thymidine double-induction system. Finally, 2 cases of apparent mosaicism for Klinefelter syndrome in fra(X) individuals were observed.

Blood Cells↗