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Biomedical subjects

J Wu

Publications and source records attributed to J Wu.

At least 1,549 records · Page 86Linked to original sources
PubMed1986

The lability of estrogen receptor: correlation of estrogen binding and immunoreactivity.

We compared the Abbott enzyme immunoassay method for estrogen receptor with a standard dextran-coated charcoal method, and studied the effects of treatments causing denaturation. Estrogen receptor values were slightly higher by the Abbott method, but the methods agreed with regard to receptors being present or absent in 94-98% of 50 cases. Heat lability of immunoreactivity by the Abbott enzyme immunoassay is comparable to the lability of estrogen binding by the estrogen receptor. Estrogen and molybdate substantially stabilized estrogen receptor during the assay, but improper handling of tissue before the assay may cause similar, substantial decreases in estrogen receptor by either method. The Abbott method is easier to use than the dextrancoated charcoal method, requires less tissue, and measures receptor with or without endogenously bound estrogen, but reagent cost is high.

Breast Neoplasms↗
PubMed1985

Structure of wild-type and mutant repressors and of the control region of the rbt operon of Klebsiella aerogenes.

Pentitol metabolism in Klebsiella aerogenes is encoded by continuous ribitol (rbt) and D-arabitol (dal) operons transcribed in bipolar fashion and sandwiched between long stretches of homologous DNA. The operons are separated by a central control region (2.2 kb) which encodes both the repressors and all the control sequences. The rbt repressor (270 amino acids) shows homology to the Escherichia coli lac repressor and other DNA-binding proteins. It is transcribed from the strand opposite the rbt operon and the intervening control region (254-bp) contains features which reflect the complex regulation. A rbt-constitutive mutant strain used in previous studies of experimental enzyme evolution encodes a truncated rbt-peptide of 133 residues due to a frameshift mutation.

Amino Acid Sequence↗
PubMed1985

Topographic EEG changes with benzodiazepine administration in generalized anxiety disorder.

The regional cerebral effects of an anxiolytic (clorazepate) in 20 patients with generalized anxiety disorder were assessed using 16-channel electroencephalogram (EEG) power spectral estimate maps of the left hemisphere. Patients were studied with double-blind random assignment to placebo or drug and were assessed at baseline, day 7, and day 14 with EEG and Hamilton Anxiety Ratings. Ten age- and sex-matched normal controls were also tested. Hamilton Anxiety Ratings were decreased significantly more in the drug group than in the placebo group. Topographic maps of EEG activity revealed decreases in occipital alpha and parietal delta, together with increases in posterior frontal (central EEG leads) and parietal beta. Decreases in delta are consistent with a lack of sedation; the reciprocal beta increases in parietal cortex are similarly consistent. This pattern of regional EEG changes in the direction of alert attentiveness, together with individual differences, observed in frontal/parietal and occipital alpha activity, suggests the importance of at least these two cortical regions for anxiolytic action. Differences between patients with generalized anxiety disorder and normals were restricted to the occipital and temporal regions. These results suggest the importance of multilead recording in assessing EEG correlates of drug action.

Adult↗
PubMed1985

Role of progesterone in the control of female sexual receptivity in Anolis carolinensis.

The synergism of progesterone (P) with estrogen (estradiol benzoate, EB) in the facilitation of receptivity in female green anole lizards (Anolis carolinensis) is independent of time since ovariectomy, but is dependent on the time interval between EB and P administration and on the time of year. There is a brief window of time during which P facilitates receptivity in females primed with a subthreshold dose of EB. Sexual receptivity is induced if the time interval between EB and P is 24 hr but not if it is 48 hr. Furthermore, female A. carolinensis appear to be more sensitive to hormone treatment during different times of the year. Ovariectomized green anole females injected with EB and P during the summer are sexually receptive, but if given the same hormone regimen during the winter, they remain unreceptive.

Animals↗
PubMed1985

Tubulin genes of the African trypanosome Trypanosoma brucei rhodesiense:nucleotide sequence of a 3.7-kb fragment containing genes for alpha and beta tubulins.

Most tubulin genes of the African trypanosome Trypanosoma rhodesiense are contained in 3.7-kb tandemly repeating units. One member of the 3.7-kb repeat family has been isolated from a T. rhodesiense genomic library, cloned, and sequenced. The 3646-bp fragment contains a complete alpha-tubulin gene and portions of two beta-tubulin genes. No introns are present. The genes are separated by 634- and 333-bp intergenic regions, which lack typical eukaryotic promoter and poly(A) signal sequences. However, both intergenic regions exhibit some structural similarity with sequences proposed to be involved in transcription termination and poly(A) addition in yeast. The 634-bp intergenic region shows homology to the "mini-exon" sequence associated with variable surface glycoprotein (VSG) and other trypanosome mRNAs. A comparable sequence is not found in the 333-bp intergenic region. T. rhodesiense alpha and beta-tubulins exhibit about 84-85% amino acid (aa) sequence homology with tubulins of mammals; the genes show about 74-75% nucleotide sequence homology. The alpha-tubulin contains 451 aa and the beta tubulin 442 aa; both have tyrosine as the C-terminal aa.

Amino Acid Sequence↗
PubMed1985

Serial cell culture and cytogenetic studies of marrow cells from a patient with monosomy 7 syndrome.

Serial bone marrow cell culture studies, with cytogenetic characterization, were performed in an 18-month-old boy with monosomy 7 syndrome--a condition that usually converts to nonlymphoblastic leukemia. Over a 12-month course, his marrow demonstrated: decreased colony formation and increased cluster formation in vitro with disease progression (consistent with preleukemia); persistence of only the monosomy 7 karyotype in direct marrow studies; and in contrast, proliferation of both 46,XY and monosomy 7 cells in in vitro marrow cultures. The findings indicate that certain dormant marrow cell populations may be expressed under in vitro culture conditions and suggest the need for determining factors which would allow their expression in vivo.

Bone Marrow↗
PubMed1984

Positron emission tomographic image measurement in schizophrenia and affective disorders.

Two analytical methods for assessing regional glucography with positron emission tomography were compared in 16 patients with schizophrenia and 11 patients with affective disorders. Patients were off all medication a minimum of 14 days and an average of 39.8 days. The subjects were administered fluorine-18-labeled 2-deoxyglucose just before receiving a 34-minute one-per-second series of unpleasant electrical stimuli to their right forearm while resting with their eyes closed in a darkened, acoustically attenuated psychophysiological testing chamber. Following monitored stimulation in the controlled environment, the subjects were scanned and the images were converted to values of glucose use in micromoles per 100 grams per minute, according to Sokoloff's model. Data were analyzed by a four-way analysis of variance (ANOVA) for independent groups (normal subjects, schizophrenic patients, and patients with affective disorders) and for repeated measures of slice level (supraventricular, midventricular , and infraventricular ), hemisphere (right, left), and anteroposterior position (four sectors). Normal individuals and patient groups both showed a significant anteroposterior gradient in glucose use, with the highest values in the sector farthest to the front. Patients with schizophrenia and those with affective illnesses showed less of an anteroposterior gradient than normal individuals, especially at superior levels, which was statistically confirmed by ANOVA. Neither the group differences in whole-brain glucose use nor the left-right asymmetries reached statistical significance. A second technique, involving reconstruction of the lateral cortical surface, also revealed differences between schizophrenics and normal individuals in the superior frontal cortex. These results are consistent with our earlier reports of a relative hypofrontal function in schizophrenia compared with controls; they also extend the finding to the affective illnesses, the other group of major psychoses.

Adult↗
PubMed1984

Acid and isoproterenol cause serotonin release by acting on opposite surfaces of duodenal mucosa.

Although most bodily serotonin (5-HT) is stored in intestinal enterochromaffin (EC) cells, the mechanism of its release is only now being elucidated. It has previously been reported that such stimuli as luminal acidification or exposure of both sides of a rabbit duodenal mucosal sheet to certain autonomic agonists stimulate release from the mucosal surface in the Ussing chamber model. The hypothesis in the present study is that acid acts only on the mucosal surface, whereas neural receptor agonists and antagonists act specifically on the serosal surface, as would be predicted by the location of acid in the gut lumen and nerve terminals at the bases of the EC cells. 5-HT release was measured by radioimmunoassay from the mucosal surface bathing solution. Duodenal mucosal sheets were exposed separately on the mucosal or serosal surfaces to acid (citric phosphate buffer, pH 5) or to isoproterenol (10(-5) M). The effect of atropine (10(-6) M) and propranolol (10(-6) M) on acid-stimulated mucosal release was studied by combining luminal acid stimulation with one of these antagonists, on either the mucosal or serosal surface. The results demonstrate significant (P less than 0.01) mucosal serotonin release (56 +/- 9 ng cm-2 hr-1) only with mucosal acidification. On the other hand, isoproterenol causes significant (P less than 0.05) serotonin release (12.4 +/- 3 ng cm-2 hr-1) only when introduced onto the serosal surface. Finally, the antagonists, atropine and propranolol, blocked acid-stimulated serotonin release only when added to the serosal surface. Since acid-induced serotonin release has been shown to be partially mediated by cholinergic and beta-adrenergic mechanisms, these findings suggest interconnection of mucosal acid receptors with submucosal neurons which mediate serotonin release by acting on the basal surface of the enterochromaffin cell.

Animals↗