We previously demonstrated that a wild-type alternatively spliced p53 (p53as) RNA exists in mouse cultured cells and normal mouse tissues at approximately 25 to 33% of the level of the major p53 RNA form. The alternative RNA transcript is 96 nucleotides longer than the major transcript as a result of alternative splicing of intron 10 sequences. The protein expected to be generated from the p53as transcript is 9 amino acids shorter than the major p53 protein and has 17 different amino acids at the carboxyl terminus. We report here that p53as protein exists in nontransformed and malignant epidermal cells and is localized to the nucleus. In addition, p53as protein is preferentially expressed during the G2 phase of the cell cycle and in cells with greater than G2 DNA content compared with the major p53 protein, which is preferentially expressed in G1. The p53as immunoreactivity is elevated and shifted to the G1 phase of the cell cycle following actinomycin D treatment of nontransformed cells but not malignant cells. In view of the dimerization and tetramerization of p53 protein which may be necessary for its DNA binding and transcriptional activation activities, the presence of p53as protein in cells has important implications for understanding the physiological function(s) of the p53 gene.

Alternative Splicing↗

PubMed1994

Regulation of ACE gene expression and plasma levels during rat postnatal development.

Angiotensin I-converting enzyme (kininase II, ACE) is a transmembrane ectoenzyme of vascular endothelial cells that is also secreted in plasma. To understand why plasma ACE levels are elevated in children compared with adults, the age-related changes in ACE mRNA and enzyme levels were studied in 1-day- to 3-mo-old rats. In the lung, a rich source of endothelial ACE, the abundance of ACE mRNA and the microsomal ACE concentration increased progressively and tripled during the first 3 mo. This large increase reflects, at least in part, development of the capillary network. In plasma, ACE levels rose dramatically a few days after birth and decreased toward adult values after the 14th day of life. Because the elevation of ACE in plasma was contemporary to thyroid maturation, the effect of perinatal suppression of thyroid function by propylthiouracil was studied. Hypothyroidism slightly delayed the evolution of ACE in lung but blunted the postnatal rise in plasma ACE levels. A 3,5,3'-triiodothyronine injection to 14-day-old hypothyroid rats failed to alter ACE mRNA levels in the lung. Thus thyroid hormones are involved in the postnatal rise in plasma ACE levels but act probably on the posttranslational proteolytic pathway involved in ACE secretion by endothelial cells or on an unknown extrapulmonary ACE source. ACE gene expression is also developmentally regulated in epithelia and male germinal cells. In the intestine, ACE mRNA levels and ACE activity were very high at birth and then decreased dramatically during the next 2 wk. In the kidney, they were low and decreased further during growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1994

Tissular expression and regulation of type 1 angiotensin II receptor subtypes by quantitative reverse transcriptase-polymerase chain reaction analysis.

Recent studies have revealed that angiotensin II (Ang II) interacts with two pharmacologically different types of seven-transmembrane domain receptors, hence named Ang II type 1 and type 2 (AT1 and AT2) receptors. cDNAs for the AT1 receptor have been cloned, and the existence of two receptor subtypes, AT1A and AT1B, has been revealed in rat and mouse. This study presents a new approach for the specific quantification of AT1A and AT1B receptor mRNAs by reverse transcription and polymerase chain reaction amplification in the presence of an AT1 receptor mutant cRNA as internal standard. Absolute quantities of mRNA are then determined by extrapolation using the standard curve generated with the internal standard. Moreover, addition of this internal standard to each tube controls for both reverse transcription and polymerase chain reaction amplification in each sample. In male Wistar rats, the highest absolute AT1A receptor mRNA levels were found in liver and kidney and those for AT1B receptor mRNA in the pituitary. Expressed as a percentage of total AT1A+AT1B receptor mRNA content, AT1A receptor mRNA content was 100% in liver, 85% in lung, 73% in kidney, 65% in aorta, 48% in adrenals, and 15% in the hypophysis. Since this approach can determine absolute AT1A and AT1B receptor mRNA quantities in different organs, it allows the study of the regulation of their expression under different pathophysiological conditions. After sodium depletion, known to induce hyperactivity of the renin-angiotensin system, adrenal AT1A and AT1B receptor mRNA levels were increased by 60% and 110%, respectively. In contrast, in renovascular hypertension (two-kidney, one clip), also associated with elevated circulating plasma renin activity, adrenal AT1B receptor mRNA levels decreased by 50%, whereas there was no change in those of AT1A. Therefore, the differential distribution and regulation of these two receptor subtypes suggest that each of them might be involved in the mediation of different biological effects of Ang II.

Adrenal Glands↗

PubMed1994

Discrepancy between plasma and lung angiotensin-converting enzyme activity in experimental congestive heart failure. A novel aspect of endothelium dysfunction.

The renin-angiotensin and cardiac natriuretic systems play an important role in the pathophysiology of congestive heart failure (CHF). The status of the membrane-bound pulmonary and renal activities of three ectoenzymes involved in the regulation of these systems-angiotensin-converting enzyme (ACE), neutral endopeptidase (NEP), and aminopeptidase A (APA)-was investigated in Wistar rats 3 months after induction of myocardial infarction (MI) and in sham-operated (control) rats. Plasma renin activity and ACE activity, plasma angiotensin II (Ang II) levels, and atrial natriuretic factor levels were simultaneously determined. The lung ACE activity was decreased in MI rats compared with control rats (P < .0001), and this decrease depended on the severity of the heart failure. In contrast, plasma ACE activity was increased in MI rats (P < .01), and this increase was also proportional to the severity of MI. Northern blot analysis showed that the lung ACE mRNA level in severe MI rats was half that of the control rats. Renal ACE activity of the MI rats was not affected, and neither renal or pulmonary NEP nor pulmonary APA activities were altered. Thus, lung ACE gene expression appears to be both organ- and enzyme-specifically regulated during CHF. Whereas plasma renin was increased in heart failure rats, plasma Ang II levels were not different from those of control rats. Thus, decreased lung ACE activity could possibly contribute to keeping plasma Ang II levels in the normal range. The decrease in lung ACE activity and mRNA levels, combined with increased plasma ACE activity, represents a novel aspect of endothelial dysfunction in CHF.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1994

Histocytochemistry of glycoconjugates in nasal inverted papilloma.

In order to investigate the changes in cellular distribution of the glycocalyces in nasal inverted papilloma, formalin-fixed, paraffin-embedded biopsy specimens of inverted papilloma were analyzed by the avidin-biotin-peroxidase complex technique for the demonstration of peanut agglutinin (PNA) receptors, concanavalin A (Canavalia ensiformis agglutinin; ConA) receptors, carcinoembryonic antigen (CEA), and keratin, and compared with normal nasal mucosa, nasal polyps, and papillary adenocarcinoma. The inverted papillomas were positive for PNA and CEA, to the same degree as papillary adenocarcinoma. Their PNA binding was related to the degree of dysplasia. The ConA reaction was intermediate between that of normal mucosa and adenocarcinoma. The results suggest that the alteration of cellular glycoprotein structure in inverted papilloma is associated with its biologic characterization.

Adult↗

PubMed1994

Thermal stabilities of hemoglobins crosslinked with different length reagents.

Bis(3,5-dibromosalicyl) succinate and glutarate were used to crosslink met-, oxy- and deoxyhemoglobins. The added flexibility of these reagents compared to the fumarate analog resulted in a more heterogeneous product but did not greatly affect the maximum thermal stability of the crosslinked hemoglobins.

Aspirin↗

PubMed1994

Evidence for guanosine triphosphate--binding proteins in Trypanosoma cruzi.

The transformation of the parasite Trypanosoma cruzi from the blood-borne trypomastigote to the intracellular amastigote constitutes a key clinical feature in the pathophysiology of Chagas' disease. That this transition occurs without change in the integrity of the plasma membrane of the parasite suggests the presence of biochemical structures, i.e., signal transduction systems, that convey information regarding the external milieu of the host so as to facilitate this transformation. In higher eukaryotes, it has been found that a heterotrimeric GTP-binding protein (G-protein), composed of alpha beta gamma subunits, constitutes a critical component of this complex. Two closely related groups of G-proteins are substrates for cholera toxin (CT)- (Gs) and pertussis toxin (PT)- (Gi1-3 and Go) dependent ADP ribosylation. In concert, they link plasma membrane receptors to adenylate cyclase, resulting in the stimulation or inhibition, respectively, of cAMP generation. In this report, we demonstrate the presence of both groups of G-proteins. Cholera toxin-dependent ADP ribosylation of 42- and 45-kD proteins was demonstrable in amastigotes (AMAST), in the cytosol of epimastigotes (EPI), and weakly in trypomastigotes (TRYP), suggesting the presence of the stimulatory GTP-binding protein, Gs, in T. cruzi. Antisera generated against the alpha s subunit of the Gs heterotrimeric protein (anti-alpha s) bound to a 45-kD protein CT substrate in the rank order TRYP >> AMAST approximately EPI cytosol. Immunoprecipitation of CT-32P-ADP-ribosylated membranes with anti-alpha s resulted in 42- and 45-kD proteins. However, no Gs-mediated activation of adenylate cyclase was demonstrable in reconstitution studies using cyc- lymphoma cells, which lack a functional Gs but possess a beta-adrenergic receptor and adenylyl cyclase enzyme. Pertussis toxin-catalyzed ADP ribosylation was demonstrable in 39-40-kD particulate proteins of EPI, less strongly in AMAST, and least in TRYP, consistent with the presence of inhibitory (Gi) and Go GTP-binding proteins. In support of this observation, immunochemical analysis of the PT substrates identified the presence of alpha o and alpha i1-2-3 in EPI, AMAST and TRYP, although, with the exception of alpha i3, both toxin and associated immunochemical PT substrates are decreased in AMAST and TRYP relative to EPI. Although the functions of these putative G-proteins in T. cruzi are still unclear, their expression may be regulated by the state of parasite differentiation.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenosine Diphosphate↗

PubMed1994

[Fine needle aspiration cytology and influencing factors in breast cancer].

The results of 200 women with primary breast cancer who had fine needle aspiration cytology prior to definitive surgery at the Peking Union Medical College Hospital were presented. Among them, aspiration cytology was positive and suspicious in 87% (174/200) and pseudonegative in 13% (26/200). Clinical factors relating to the success of these aspiration were evaluated. The most significant factor was which physician performed the aspiration. Size of the lesion and type of the cancer were also important influences on the aspiration. Experiences in aspiration cytology were introduced by author.

Adenocarcinoma↗

PubMed1994

[Study on auto-solidified tumor vaccine].

In order to evaluate the immune effect of Auto-solidified tumor vaccine induced by thermal doses of 65 degrees C for 5 minutes on the killing and inactivation of cancer cells in operation, a series of experimental and clinical studies were carried out, the results showed that Balb/c mice immunized with ASTV could tolerate the aggression of H22 3 x 10(8) cancer cells with efficiency of 93.3% (28/30), the inoperable advanced hepatic cancer proved in operation was hypothermited and ASTV was made for immune injection postoperatively, with the clinical efficiency 76.8% (53/69), and 5-year survival rate 23% (9/39), the difference with control group is significant. In recent years, it is recognized once again that tumor can induce specific immunity. The most important matter is how to stimulate the host to produce effective cellular immunity. Our results showed that the thermal biological effect could inactivate cancer cell and change nuclear antigen in host net-like immunity system. Under gene regulation, the host can obtain the cellular immune effect against cancer cells.

Adult↗

PubMed1994

[Identification of microsporidian pathogen in Chinese medicinal insect Martianus dermestoides Chevr].

Explore the source record for details and available documents.

Animals↗

PubMed1994

Mechanisms of brain injury with deep hypothermic circulatory arrest and protective effects of coenzyme Q10.

Sixteen dogs, divided randomly into a control group and coenzyme Q10 group (10mg/kg, intraperitoneally before the operation), underwent deep hypothermic circulatory arrest with cardiopulmonary bypass, as is done clinically. At four time points cerebral cortex and cerebrospinal fluid specimens were collected to study free radical formation, energy metabolism, and ultrastructure. During cardiopulmonary bypass cerebral electron spin resonance spectra and malondialdehyde contents were progressively higher than before bypass, especially at the 60 minutes of circulatory arrest and 30 minutes of reperfusion (p1 < 0.01, p2 < 0.05). In the coenzyme Q10 group at the latter two time points, they had increased less than in the control group at same time points (p1 < 0.02, p2 < 0.005). Adenosine triphosphate content in the cortex during bypass decreased gradually from the prebypass level (p1 < 0.02, p2 = p3 < 0.001), while lactate in cerebrospinal fluid increased (p1 < 0.05, p2 = p3 < 0.001). In the coenzyme Q10 group, adenosine triphosphate at the latter two time points was greater than that in the control group (p1 = p2 < 0.05), while the lactate changes were not significantly different from control at each time point (all p > 0.05). Ultrastructure of the cortex was normal before bypass and almost normal during bypass, but it was obviously abnormal at 60 minutes of circulatory arrest and more seriously abnormal at 30 minutes of reperfusion. In the coenzyme Q10 group the abnormality was obviously reduced. The results suggest that oxygen-derived free radicals and abnormal energy metabolism might play critical roles in brain ischemia/reperfusion injury. Coenzyme Q10 could protect the brain by improving cerebral metabolism.

Adenosine Triphosphate↗

PubMed1994

[Determination of E. coli with MUG (Fluorocult)-lauryl sulfate broth for the testing of microbial contamination in drugs].

A test method for the determination of Escherichia coli in plant materials with the MUG (Fluorocult)-lauryl sulfate broth is described. It was found that more than 75% of the commonly used vegetable drugs exhibit fluorescence quench effects to different degrees when determining E. coli with the MUG-lauryl sulfate broth. Therefore a simple combination of two procedures was evaluated in order to avoid the matrix interferences: in a first step the drug sample was diluted eight times in a proportion of 1:10 with MUG-lauryl sulfate broth in eight separate tubes from 1 g down to 10(-7) g/tube (1st test series) and the resulting samples were incubated for 40 h at 36 degrees C. Subsequently, the tubes were tested for fluorescence. If the first tube of this series was found without fluorescence, in a second step a subsequent series of MUG-lauryl sulfate broth (2nd test series) was inoculated with 0.5 ml of the incubated culture from each of the first three tubes of series 1 and incubated again for 24 h at 36 degrees C. The results were evaluated from gas production, fluorescence as well as indole formation. Thus, the method allowed a simple and reproducible enumeration of E. coli for the test on microbial contamination in medicinal plant materials. The method was successfully applied to samples of 38 vegetable drugs for quantitative determination of E. coli (8 samples were found being contaminated with E. coli).

Culture Media↗

PubMed1994

Derivatives of 3-alkyl-N-hydroxysuccinimide: probing the effect of structure on bioactivity toward human leukocyte elastase.

A structure-activity relationship study was conducted in order to probe the nature of the interaction between some 3-alkyl-N-hydroxysuccinimide derivatives and human leukocyte elastase. The structural features in substituent X (structure I) that lead to the manifestation and optimization of inhibitory activity have been examined. The data suggest that the presence of an alkyl or aryl(sulfonyloxy) group in the active compounds may serve a triple purpose, namely, it functions as a good leaving group as dictated by the established mechanism of action of this class of compounds, secondly, it may enhance binding by assuming a favorable spatial orientation and, thirdly, it may increase the chemical reactivity of the carbonyl carbon in the bioactive compounds.

Chemical Phenomena↗

PubMed1994

Immune responses to Epstein-Barr virus in atomic bomb survivors: study of precursor frequency of cytotoxic lymphocytes and titer levels of anti-Epstein-Barr virus-related antibodies.

Precursor frequencies of cytotoxic lymphocytes to autologous Epstein-Barr virus-transformed B cells and serum titers of anti-Epstein-Barr virus-related antibodies were measured in 68 atomic bomb survivors to clarify the immune mechanism controlling Epstein-Barr virus infection. The precursor frequency was negatively correlated with the titer of anti-early antigen IgG, which is probably produced at the stage of viral reactivation. A positive correlation between the precursor frequency and titer of anti-Epstein-Barr virus-associated nuclear antigen antibody was also observed, indicating that the precursor frequency reflects the degree of in vivo destruction by T cells of the virus-infected cells. These results suggest that T-cell memory specific to Epstein-Barr virus keeps the virus under control and that the precursor frequency assay is useful for the evaluation of immune responses to Epstein-Barr virus. However, no significant effect of atomic bomb radiation on the precursor frequency was observed in the present study, probably due to the limited number of participants.

B-Lymphocytes↗