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J Miles

Publications and source records attributed to J Miles.

At least 73 records · Page 4Linked to original sources
PubMed1992

Protein affinity chromatography with purified yeast DNA polymerase alpha detects proteins that bind to DNA polymerase.

We have overexpressed the POL1 gene of the yeast Saccharomyces cerevisiae and purified the resulting DNA polymerase alpha polypeptide in an apparently intact form. We attached the purified DNA polymerase covalently to an agarose matrix and used this matrix to chromatograph extracts prepared from yeast cells. At least six proteins bound to the yeast DNA polymerase alpha matrix that did not bind to a control matrix. We speculate that these proteins might be DNA polymerase alpha accessory proteins. Consistent with this interpretation, one of the binding proteins, which we have named POB1 (polymerase one binding), is required for normal chromosome transmission. Mutations in this gene cause increased chromosome loss and an abnormal cell morphology, phenotypes that also occur in the presence of mutations in the yeast alpha or delta polymerase genes. These results suggest that the interactions detected by polymerase affinity chromatography are biologically relevant and may help to illuminate the architecture of the eukaryotic DNA replication machinery.

Chromatography, Affinity↗
PubMed1992

Evidence that POB1, a Saccharomyces cerevisiae protein that binds to DNA polymerase alpha, acts in DNA metabolism in vivo.

Potential DNA replication accessory factors from the yeast Saccharomyces cerevisiae have previously been identified by their ability to bind to DNA polymerase alpha protein affinity matrices (J. Miles and T. Formosa, Proc. Natl. Acad. Sci. USA 89:1276-1280, 1992). We have now used genetic methods to characterize the gene encoding one of these DNA polymerase alpha-binding proteins (POB1) to determine whether it plays a role in DNA replication in vivo. We find that yeast cells lacking POB1 are viable but display a constellation of phenotypes indicating defective DNA metabolism. Populations of cells lacking POB1 accumulate abnormally high numbers of enlarged large-budded cells with a single nucleus at the neck of the bud. The average DNA content in a population of cells lacking POB1 is shifted toward the G2 value. These two phenotypes indicate that while the bulk of DNA replication is completed without POB1, mitosis is delayed. Deleting POB1 also causes elevated levels of both chromosome loss and genetic recombination, enhances the temperature sensitivity of cells with mutant DNA polymerase alpha genes, causes increased sensitivity to UV radiation in cells lacking a functional RAD9 checkpoint gene, and causes an increased probability of death in cells carrying a mutation in the MEC1 checkpoint gene. The sequence of the POB1 gene indicates that it is identical to the CTF4 (CHL15) gene identified previously in screens for mutations that diminish the fidelity of chromosome transmission. These phenotypes are consistent with defective DNA metabolism in cells lacking POB1 and strongly suggest that this DNA polymerase alpha-binding protein plays a role in accurately duplicating the genome in vivo.

Amino Acid Sequence↗
PubMed1991

Measurement of plasma acetate kinetics using high-performance liquid chromatography.

Previous studies suggest that plasma acetate may be an important fuel in man, accounting for approximately 10% of energy expenditure. Available methods for the determination of plasma acetate kinetics are difficult and time consuming. We describe here a procedure for the determination of plasma acetate concentration and specific activity using automated high-performance liquid chromatography that is precise and sensitive and accommodates large numbers of samples. The procedure involves extraction from plasma with diethyl ether, derivatization with bromoacetophenone, and separation on a C-18 reversed-phase column. The specific activities of D-beta-hydroxybutyrate and lactate can also be determined. Acetate turnover was measured in four dogs and was similar to that previously reported in sheep and humans. Transport of [14C]acetate into red blood cells was negligible.

3-Hydroxybutyric Acid↗
PubMed1991

Give us a daily bed.

Explore the source record for details and available documents.

Ambulatory Surgical Procedures↗
PubMed1990

Intractable complex partial seizures associated with occult temporal lobe encephalocele and meningoangiomatosis: a case report.

Occult congenital temporal lobe encephalocele has rarely been reported in association with medically intractable complex partial seizures. The four previously reported cases were unsuspected preoperatively. We present the case of an 18-year-old woman with intractable complex partial seizures since age 13. Seizure onset was electrically localized to the right temporal lobe. Preoperative neuroimaging studies revealed a middle fossa defect and inferior herniation of the right temporal lobe. Pathologic examination of the resected encephalocele revealed prominent features of meningoangiomatosis. We believe this to be the first case of temporal lobe encephalocele and epilepsy to be diagnosed preoperatively, and the first case also to be associated with meningoangiomatosis. The relevant literature on meningoangiomatosis and on temporal lobe encephalocele as a cause of epilepsy is reviewed.

Adolescent↗
PubMed1990

The effect of picture priming on event-related potentials of normal and disabled readers during a word recognition memory task.

Normal and one subtype of disabled readers were compared in their visual event-related potentials (ERPs) that were elicited by primed and unprimed words during a recognition memory task. The primed words were preceded by a picture having the same denotative meaning, while unprimed words were preceded by a picture having a non-associated meaning. Normal readers exhibited consistently greater amplitude than the disabled readers to unprimed words with a negative wave at 455 ms (N400). For the disabled readers, this N400 was evident, though somewhat smaller, than for controls, at fronto-central placements, but absent at the lateral parietal and occipital sites. Priming a word with a picture reduced N400 amplitude for both the normal and disabled readers. There were no remarkable differences between groups in their ERPs to the pictures. The pattern of ERP results obtained seems to reflect a failure of this subtype of disabled readers to engage long-term, semantic memory, while their short-term linguistic processing is intact.

Arousal↗
PubMed1990

Isoflurane and whole body leucine, glucose, and fatty acid metabolism in dogs.

Following 4 h of general anesthesia with halothane [1.5 minimum alveolar concentration (MAC)]-nitrous oxide (50% in oxygen), whole body protein synthesis is decreased and the rate of leucine oxidation is increased in dogs. To evaluate the effects of general anesthesia with isoflurane on whole body fuel metabolism and the effects of duration of anesthesia on these processes, eight dogs were studied, once in the conscious state (over 9 h) and again prior to and during isoflurane anesthesia (1.5 MAC) for 3.5 h (n = 8). Three additional dogs were studied in the conscious state and over 5 h of anesthesia. Changes in protein, fatty acid, and glucose metabolism were estimated using isotope dilution techniques, employing simultaneous infusions of L-[1-14C]leucine, [6-3H]glucose and [9,10-3H]palmitate. Ten minutes after the beginning of the administration of isoflurane, total leucine carbon flux, leucine oxidation, and leucine incorporation into proteins decreased (P less than 0.05), resulting in a slight decrease in the ratio of leucine oxidation to nonoxidative leucine disappearance (LOX/NOLD, P less than 0.05), an indicator of leucine catabolism. Throughout the 5 h of anesthesia, whole body protein synthesis remained decreased (P less than 0.01), whereas leucine flux and oxidation increased progressively throughout the remainder of the study, resulting in a more than 80% increase in the ratio of LOX/NOLD. After 10 min of isoflurane anesthesia, both plasma free fatty acid concentrations and palmitate turnover had decreased by more than 70% (P less than 0.001) and remained suppressed (P less than 0.001) throughout the remainder of the anesthesia, consistent with decreased lipolysis. Glucose production was increased 10 min (P less than 0.05) following induction of anesthesia and peripheral glucose utilization was decreased following 3.5 h of isoflurane anesthesia (P less than 0.05). These data strongly suggest a widespread and immediate metabolic effect of isoflurane anesthesia, which includes peripheral insulin resistance to glucose disposal, decreased lipolysis, and a progressive increase in protein wasting with increasing duration of anesthesia.

Anesthesia, General↗
PubMed1990

Helping people prepare. Catholic healthcare facilities can give patients advice on advance directives.

Although state courts have tended recently to allow surrogates to make healthcare treatment decisions for incompetent patients, the Missouri Supreme Court went against the trend by denying Nancy Cruzan's family the right to withdraw her artificial nutrition and hydration. The U.S. Supreme Court upheld the Missouri decision. At the same time, however, the Court's opinions strongly implied that it would uphold other state courts' decisions affirming the right of surrogates to make treatment decisions for incompetent patients. In his majority opinion, moreover, Chief Justice William Rehnquist upheld a competent person's liberty interest in refusing medical treatment, including artificial nutrition and hydration. Catholic healthcare facilities should be prepared to provide information to the many patients and long-term care residents seeking advice on advance directives as a result of the Court's ruling. Because living wills are proving to be less effective than many at first thought they would be, providers can best help individuals by giving them information on preparing proxy documents.

Advance Directives↗
PubMed1990

Fat-body-specific expression of the Drosophila Lsp-2 gene.

The larval serum protein-2 gene (Lsp-2) of Drosophila melanogaster is expressed at a very high level in the fat body of third-instar larvae. Here we report that Lsp-2 transcription in adult flies produces a unique mRNA localized in the adult adipose tissue of the head in both sexes. To identify regulatory regions of this Drosophila gene, Lsp-2 5'-flanking DNA sequences were fused to the E. coli beta-galactosidase gene (lacZ). Transient expression of the hybrid gene in third-instar larvae indicates that 230 bp just upstream from the 'TATA box' of the Lsp-2 gene are sufficient for larval fat body-specific expression.

Animals↗
PubMed1989

A simple system for image directed stereotaxis.

A simple system for CT directed stereotaxis has been developed. This technique represents a true three-dimensional solution to the problems of CT stereotaxis and is therefore free of positional constraints relating to the orientation of the patient/stereotactic instrument/CT scan plane, but is not dependent on the relatively complicated mathematical methods required by existing techniques. The preliminary series of 17 procedures are presented, 13 of these were designed to obtain tissue diagnosis. One patient had effective stereotactic aspiration of a colloid cyst of the third ventricle. The stereotactic instrument itself is lightweight and easy to use, a wide range of target trajectories including low sites are possible. The design of this instrument would be particularly well suited for MR directed stereotaxis.

Biopsy↗
PubMed1988

Cytogenetic analysis in renal cell carcinoma: correlation with tumor aggressiveness.

Twenty-eight tissue specimens from 26 patients with renal cell carcinoma were subjected to cytogenetic analysis using a newly developed combined method of enzymatic technique and short term tissue culture. Of the 28 tumor samples studied, 21 were chromosomally abnormal. Four (including two oncocytomas) were normal, and three did not grow in tissue culture. Of the 21 tumors with abnormal chromosomes, the most frequent abnormality was either trisomy or tetrasomy of chromosome 7 (18 of 21 tumors). In four of these tumors, trisomy 7 was the only visible abnormality. Ten tumors contained abnormalities of chromosome 3. Three showed a previously reported chromosome 3 interstitial deletion, five were hyperdiploid, and two revealed a monosomy 3. Of these 10 patients, six have had disease progression, compared to one of the 16 remaining patients without an abnormal chromosome 3. These data suggest that abnormalities of chromosome 7 represent a primary abnormality, and that when these abnormalities are present in association with abnormalities involving chromosome 3, they may correlate with a more aggressive clinical course and a corresponding higher stage of disease at diagnosis.

Carcinoma, Renal Cell↗
PubMed1988

Quantification of the glycolytic origin of plasma glycerol: implications for the use of the rate of appearance of plasma glycerol as an index of lipolysis in vivo.

To assess whether plasma glycerol could be directly derived from plasma glucose, nine postabsorptive dogs were infused with [U-14C] glucose and [2-3H] glycerol to measure the rates of appearance of plasma glucose and glycerol and the conversion of plasma glucose to glycerol before (basal) and after two hours of infusion of glucose (45 mumol/kg/min). Basally (plasma glucose 4.9 +/- 0.2 mmol/L; plasma insulin 5.9 +/- 0.2 microU/mL), rates of appearance of plasma glucose and glycerol were 20 +/- 2 and 5.9 +/- 1.3 mumol/kg/min, respectively, and 1.6 +/- 0.6% of plasma glycerol was derived from plasma glucose. After glucose infusion (plasma glucose 9.1 +/- 0.7 mmol/L; plasma insulin 21.1 +/- 1.9 microU/mL), the rate of appearance of plasma glycerol decreased 80% to 1.1 +/- 0.3 mumol/kg/min and the percent of plasma glycerol from glucose increased significantly to 6.9 +/- 2.9. However, the absolute rate of conversion of glucose to glycerol did not change (0.09 +/- 0.03 v 0.07 +/- 0.03 mumol/kg/min). We conclude that even under conditions of stimulated glycolysis and inhibited lipolysis, only a small amount of plasma glycerol is derived from plasma glucose. Thus, rates of appearance of plasma glycerol can be used as a measure of rates of overall lipolysis in vivo.

Animals↗
PubMed1988

Genomic defects in nonfamilial renal cell carcinoma. Possible specific chromosome change.

Using a newly developed combined method of enzymatic technique and short-term tissue culture, 30 tumor specimens from 26 patients with nonfamilial renal cell carcinoma were subjected to cytogenetic analysis. Of the 26 patients, 19 had chromosomally abnormal tumors, four (including two oncocytomas) were normal, and three did not grow. The modal chromosome numbers ranged from 44 to 98 (including two pseudotetraploids). Banding analysis revealed 38 clonal aberrations and ten nonclonal aberrations. Abnormalities were of structure and number. The most consistent clonal abnormality was a trisomy or tetrasomy chromosome 7 occurring in tumors from 15 of the 19 patients with cytogenetically abnormal tumors. In four cases, trisomy 7 was the only visible abnormality observed, and in an additional five it was the only abnormality in two or more cells. An abnormal chromosome 3 was found in ten (38%) of the cases. Two were trisomic for #3, two were monosomic, three were hyperdiploid, and three had interstitial deletions with breakpoints clustered from p11 to p25. In only one case was a deleted #3 the only abnormality observed in a clone of cells. Loss of the sex chromosome was seen in eight (35%) of the 23 chromosomally abnormal cases including all four (100%) patients with bilateral disease. One of the patients with bilateral disease had an abnormal clone with monosomy X as the only abnormality. These data suggest that trisomy or tetrasomy 7 more often represents the specific primary abnormality than abnormalities of either chromosome 3 or the sex chromosomes. From this, a model of chromosomal progression may be constructed for nonfamilial renal cell carcinoma, which could assist in pathologic classification and prognostic and therapeutic considerations.

Carcinoma, Renal Cell↗