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Biomedical subjects

C R Merril

Publications and source records attributed to C R Merril.

At least 109 records · Page 6Linked to original sources
PubMed1988

Use of two-dimensional electrophoretic protein maps in studies of schizophrenia.

High resolution two-dimensional electrophoresis (2DE) and silver staining have provided a technology capable of mapping large numbers of proteins from tissues and body fluids. Further identification of individual proteins that have been visualized by 2DE includes their characterization by immunodetection methods and by obtaining amino acid sequences from which antibody and synthetic oligonucleotide probes can be synthesized. As many as 3,500 individual proteins may be observed on a single electrophoretogram. This capacity to observe gene products permits the scanning of as many as 3.5 megabases of the protein coding regions of the genome for mutational events on each gel, and may also provide evidence concerning abnormal rates of protein synthesis or degradation, posttranslational modifications, and the presence of gene products of exogenous origin. The application of this technology has revealed a pair of abnormal cerebrospinal fluid (CSF) proteins (40KD) in one-third of schizophrenic patients screened. These abnormal proteins have never been observed in CSF from normal controls. However, they have been detected in some diseases of the central nervous system that may be of viral origin. Structural studies on these proteins should provide evidence of their origin, while ongoing studies of brain proteins may provide additional clues about this disease.

Cerebrospinal Fluid Proteins↗
PubMed1988

Creutzfeldt-Jakob disease following pituitary-derived human growth hormone therapy: a new American case.

A fourth histologically-confirmed American case of Creutzfeldt-Jakob disease (CJD) related to human growth hormone (hGH) therapy is reported. Like kuru, the illness was dominated by cerebellar signs and relatively little mental deterioration. The diagnosis was strongly supported premortem by the presence of two abnormal 30 kDa proteins in the CSF that are seen almost exclusively in CJD. The characteristic clinical picture coupled with such biochemical data allow a reasonably accurate premortem diagnosis of hGH-related iatrogenic CJD to be made.

Adult↗
PubMed1988

'Catalysts' for polyacrylamide gel polymerization and detection of proteins by silver staining.

The crosslinker diacrylyl-piperazine produces polyacrylamide gels which display improved electrophoretic separation of proteins and better physical strength. It also produces gels with improved detection of proteins by ammoniacal silver staining by reducing the background. This reduced background provided us with an opportunity to investigate residual background staining caused by the catalytic reagents utilized in the polymerization of acrylamide gels. The commonly used catalyst system, tetramethyl-ethylenediamine and ammonium persulfate was shown to be responsible for the yellow staining background found after a prolonged development time with silver staining. An alternate catalyst system has been designed to decrease further the formation of this background staining. Dimethyl-piperazine or tetramethylethylenediamine, potassium or ammonium persulfate, and sodium thiosulfate are shown to provide for gels which have excellent mechanical and staining characteristics. These catalytic systems produce little background staining despite prolonged development time with the ammoniacal silver stain, and they reduce background staining with the dichromate silver stain.

Acrylic Resins↗
PubMed1988

HDL particle associated proteins in plasma and cerebrospinal fluid: identification and partial sequencing.

The proteins from plasma HDL particles isolated by immunoaffinity chromatography on anti-apolipoprotein A-1 affinity columns have been analysed and purified by high resolution two dimensional gel electrophoresis. Two of the lipoprotein-associated proteins found in the HDL plasma fraction, previously referred to as NA1 and NA2, have also been found in cerebrospinal fluid. After separation by 2DGE, these two proteins were transferred to PVDF membranes, stained and cut out for N-terminal sequencing. The partial sequences (11 and 13 amino acids) obtained for the two HDL particle associated proteins do not match any of those included in the December 1987 National Biomedical Research Foundation (NBRF) database, and there are no significant sequence similarities.

Amino Acid Sequence↗
PubMed1987

Protein polymorphisms detected by two-dimensional electrophoresis: an analysis of overall informativeness of a panel of linkage markers.

Forty-two independent polymorphic loci are detectable by two-dimensional electrophoresis (2DE) of four peripherally accessible human tissues. Fifteen have been chromosomally mapped and, taken together, these constitute a useful panel of markers for genetic linkage studies in humans. An analysis of the overall informativeness for linkage of this panel of markers is presented, taking into account the effect of varying the number of families or matings studies. Use of 2DE polymorphic markers for linkage of genetically determined behaviour traits in humans and mice is reviewed.

Blood Proteins↗
PubMed1986

Abnormal proteins in the cerebrospinal fluid of patients with Creutzfeldt-Jakob disease.

We studied more than 300 cerebrospinal fluid proteins from 21 patients with Creutzfeldt-Jakob disease. We also examined cerebrospinal fluid from 100 normal controls and more than 400 patients with various neurologic disorders other than Creutzfeldt-Jakob disease. Four abnormal proteins that were identified in the patients with Creutzfeldt-Jakob disease were absent in the normal persons. Two of these proteins (Mr [relative molecular mass], 40,000; pl [isoelectric point], 5.7 and Mr 40,000; pl 5.9) were also present in some patients with multiple sclerosis, herpes simplex encephalitis, schizophrenia, Parkinson's disease, or Guillain-Barré or Behçet's syndrome. Two proteins (Mr 26,000; pl 5.2 and Mr 29,000; pl 5.1) were present in all patients with Creutzfeldt-Jakob disease and in 5 of 10 patients with herpes simplex encephalitis, but in none of the other control groups. A subsequent blinded study of these cerebrospinal fluid proteins from patients with Creutzfeldt-Jakob disease, Alzheimer's disease, Huntington's disease, multi-infarct dementia, parkinsonism dementia of Guam, or the specific dementia of the acquired immunodeficiency syndrome resulted in the ability to distinguish all cases of Creutzfeldt-Jakob disease from the other types of dementia. Although the identity and origin of the abnormal spinal fluid proteins are not yet known, these preliminary results suggest that their presence may help in the diagnosis of Creutzfeldt-Jakob disease.

Cerebrospinal Fluid Proteins↗
PubMed1986

A silver stain for the rapid quantitative detection of proteins or nucleic acids on membranes or thin layer plates.

A relatively simple silver stain which takes less than 15 min to perform has been developed for the detection of nanogram quantities of proteins and DNA on cellulose membranes and thin layer plates. This stain demonstrates a reproducible curvilinear relationship between silver density and the amount of protein or DNA, over an averaged concentration range from 1 to 300 ng for proteins and 10 to 710 ng for DNA. The ease of staining proteins and DNA on membranes, combined with the stain's sensitivity and reproducibility, permits the use of this procedure for the quantitative determination of nanogram amounts of proteins and DNA. The simplicity of this silver stain has also permitted a survey of the staining properties of individual amino acids, purine and pyrimidine bases, nucleosides, nucleotides, homopolymers, and small peptides of known sequence. This survey demonstrated the importance of the basic amino acids, particularly lysine and histidine, and the sulfur-containing amino acids in the detection of proteins. It also indicated that the purine bases may play an important role in the detection of DNA.

Chromatography, Thin Layer↗
PubMed1985

Genetic brain polypeptide variants in inbred mice and in mouse strains with high and low sensitivity to alcohol.

Twelve genetically determined brain polypeptide charge variants were identified by comparing cerebellar vermis of 7 inbred mouse strains and of mice selectively bred from 8 strains closely related to these 7 ancestral strains and one other for acute behavioral sensitivity to the sedative effects of ethanol. The selectively bred ethanol-sensitive (LS, long sleep) and insensitive (SS, short sleep) mice exhibited different allelic variants at 6 of these 12 gene loci expressed in the cerebellum. Variant polypeptide A1 (81 kdalton, pI 5.6) was shown to be associated with the membrane of synaptosomal mitochondria and to exhibit a basic variant in SS mice that is determined by a dominant allele. Other variant polypeptides showed codominant inheritance in F1 crosses. However, the phenotype of no single one of these brain polypeptides consistently correlated with the ethanol behavioral sensitivity of the 7 inbred mouse strains nor of 8 recombinant inbred (B X D, C57BL X DBA) strains. This finding supports the hypothesis that a substantial amount of inbreeding, leading to random fixation of alleles independent of selection for ethanol sensitivity, occurred during the breeding of the SS and LS mice. The present findings of a lack of a strong association between sleep time and a brain polypeptide variant do not preclude the existence of a major gene effect contributing to variation in acute sensitivity to ethanol but are consistent with reports that multiple loci are responsible for the difference in ethanol sensitivity between SS and LS mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Twenty-seven protein polymorphisms by two-dimensional electrophoresis of serum, erythrocytes, and fibroblasts in two pedigrees.

Twenty-seven independent polymorphic loci were detected by two-dimensional electrophoresis (2DE) of serum, erythrocytes, and fibroblasts in two large families and analyzed for linkage to classical genetic markers. We detected seven serum, four erythrocyte, and 17 fibroblast protein loci that exhibited charge variation in these two families and in a sample of unrelated individuals. The genetic basis of protein variants was confirmed by quantitative gene-dosage dependence and by conformance to Mendelian transmission in the two families, except for four rare variants for which transmission analysis was not possible. Linkage analysis demonstrated that each of the variants represent products of independent loci, with the exception of erythrocyte locus (RBC4), which we also detected in fibroblasts (NC27). Two allozyme polymorphisms, glyoxalase-1 (GLO1) and phosphoglucomutase-3 (PGM3) were specifically identified here based on genotypic concordance and molecular mass. Unknown fibroblast protein (NC22) may be linked to apolipoprotein E (lod score = 2.8 at theta m = theta f = 0), while a serum protein locus (SER1) may be linked to alpha-haptoglobin (lod score = 2.54 at theta m = .20, theta f = .01). Six of seven polymorphic serum loci were previously located on two-dimensional gels: alpha-1 antitrypsin (PI), Gc-globulin (GC), alpha-2 HS glycoprotein (HSGA), alpha-haptoglobin (HP), and two apolipoproteins (APOE and APOA4). Six of 17 polymorphisms detected in fibroblasts were positionally identical to polymorphic loci seen in lymphocytes. These studies indicate a minimum level of average protein charge heterozygosity of approximately 2.2% for the most predominant human cellular proteins and of 5.6% for the most predominant proteins of serum.

Alleles↗
PubMed1985

Differences in cerebrospinal fluid proteins between patients with schizophrenia and normal persons.

A survey of cerebrospinal fluid (CSF) proteins from normal persons and patients with schizophrenia reveals differences between the two populations. Computer-assisted densitometry of 68 proteins, resolved by two-dimensional electrophoresis and made visible by silver staining, shows six changes. Compared with their occurrence in the normal group, two proteins are increased in the schizophrenic patients by 22% and 27%, while four proteins are decreased by 29%, 46%, 20%, and 37% (p less than 0.005). Furthermore, two additional 40 000-Da proteins are found in CSF from 31.5% of the schizophrenic patients. Although these disease-associated proteins have not yet been found in 12 other neurological and psychiatric conditions, they have been found in patients with herpes simplex encephalitis (90%), Creutzfeldt-Jakob disease (67%), multiple sclerosis (13%), Parkinson's disease (12%), and a single case of Guillain-Barré syndrome. These two 40 000-Da proteins have never been found in CSF from any of 99 normal persons.

Adolescent↗
PubMed1984

Two-dimensional electrophoresis and "ultrasensitive" silver staining of cerebrospinal fluid proteins in neurological diseases.

Cerebrospinal fluid (CSF) proteins, as resolved by two-dimensional electrophoresis and made visible by silver staining, have been examined in patients with various neurological diseases and normal volunteers. The patterns for 15 of 20 patients with Parkinson's disease showed a protein (Mr 25 000) with charge similar to albumin, which was not seen in the patterns for any of 91 normal volunteers. Patterns for 21 of 22 multiple sclerosis patients showed novel immunoglobulin light chain proteins, also not present in the CSF of any normal volunteers. Quantitative analysis by computer-assisted densitometry in Parkinson's disease and multiple sclerosis showed that 20 of 68 and 33 of 85 proteins, respectively, were significantly altered as compared with proteins in the normal population. This ability to characterize both Parkinson's disease and multiple sclerosis molecularly provides a broad baseline for improved clinical diagnosis and may serve as an aid in exploring the underlying pathophysiology. These studies illustrate the potential of applying this methodology in the study of neurological diseases.

Adult↗
PubMed1984

"Ultrasensitive" silver stains: their use exemplified in the study of normal human cerebrospinal fluid proteins separated by two-dimensional electrophoresis.

We have developed a series of photochemical silver stains that are more than 100 times as sensitive as the Coomassie Blue stains. These stains facilitate the quantitative estimation of proteins in two-dimensional gel patterns. Recently, we discovered that by using light (photodevelopment) to catalyze the reduction of ionic silver to metallic silver, we could produce an image of proteins on polyacrylamide gels within 10 min after their electrophoretic separation. We used these stains to detect proteins resolved in two-dimensional electrophoretograms of lumbar cerebrospinal fluid from 51 normal human volunteers, finding no qualitative protein changes in the more than 300 CSF polypeptides resolved on each individual's electrophoretogram. We quantified 67 of these proteins per individual with computer-assisted densitometry, only five of which showed significant quantitative age-related alterations. We saw no sex-related differences. This consistency in the protein pattern for cerebrospinal fluid from normal individuals allows it to serve as a baseline for comparisons with disease states.

Adult↗
PubMed1983

Maternal transmission in Huntington's disease.

The effect of maternal transmission on age at onset of Huntington's disease (HD) was examined in 100 unrelated pedigrees. The age at which abnormal movement disorder first appeared could be estimated in 238 patients. More than twice as many of the late-onset cases (age 50 or later) inherited the HD gene from an affected mother than from an affected father. Affected offspring of late-onset females also had late-onset disease while those of late-onset males had significantly earlier ages of onset. This pattern of maternal inheritance suggests a model where the late-onset form of HD is related to a maternally transmitted factor such as the mitochondrion and its genome.

Adult↗
PubMed1983

Identification of a yellow gene-specific protein in Drosophila melanogaster by two-dimensional gel electrophoresis.

Analysis of temperature-sensitive mutants suggests that the yellow (y) gene in Drosophila melanogaster is expressed at a different time in each cell type that gives rise to the various structures of the adult cuticle. An important step in analyzing the regulation of this gene requires identification of the y structural protein. A polypeptide has been identified which correlates with the presence or absence of a functional y gene. Furthermore, this protein has the tissue distribution profile expected of the y structural gene product. The ability to locate this gene was facilitated by the use of coisogenic stocks, two-dimensional electrophoretic protein separation, and an ultrasensitive silver protein stain.

Animals↗