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Biomedical subjects

N Wang

Publications and source records attributed to N Wang.

At least 433 records · Page 24Linked to original sources
PubMed1990

Bovine dopamine beta-hydroxylase, primary structure determined by cDNA cloning and amino acid sequencing.

A cDNA clone encoding bovine dopamine beta-hydroxylase (DBH) has been isolated from bovine adrenal glands. The clone hybridizes to two oligonucleotide probes, one based on a previously reported active site peptide [DeWolf, W. E., Jr., et al. (1988) Biochemistry 27, 9093-9101] and the other based on the human DBH sequence [Lamouroux, A., et al. (1987) EMBO J. 6, 3931-3937]. The clone contains a 1.9-kb open reading frame that codes for the soluble form of bovine DBH, with the exception of the first six amino acids. Direct confirmation of 93% of the cDNA-derived sequence was obtained from cleavage peptides by protein sequencing and mass spectrometry. Differences were found between these two sequences at only two positions. Of the four potential N-linked carbohydrate attachment sites, two, Asn-170 and Asn-552, were shown to be partially and fully glycosylated, respectively. Within the 69% of the protein sequence confirmed by mass spectrometry, no other covalent modifications were detected.

Adrenal Glands↗
PubMed1990

Tubulin binds specifically to the signal-transducing proteins, Gs alpha and Gi alpha 1.

Participation of cytoskeletal elements in regulation of hormonal response and responsiveness has been suggested by several laboratories. Addition of dimeric tubulin to rat cerebral cortex synaptic membranes causes stable inhibition of adenylyl cyclase, and the molecular basis for this effect appears to require a direct interaction between tubulin and G proteins. To test whether such tubulin-G protein interaction occurred, several purified G proteins were bound to nitrocellulose, and 125I-tubulin overlay studies were performed. 125I-Tubulin bound to the alpha subunits of Gs and Gil with high specificity and an apparent Kd of approximately 130 nM. Other G protein alpha subunits (alpha i2, alpha i3, alpha 0, and transducin) displayed a much lower affinity for tubulin, despite the much closer relationship of those proteins to alpha il than to alpha s. Association of beta gamma subunits with alpha il or alpha s did not alter the binding of tubulin to these G protein heterotrimers, and the binding of a hydrolysis-resistant GTP analog to the alpha subunits was similarly without effect. These results suggest that tubulin forms complexes with specific G proteins and these complexes might provide a locus for the interaction of cytoskeletal components and signal transduction cascades. These results also provide evidence of a functional distinction among the closely related alpha i subtypes.

Animals↗
PubMed1990

Two identical active X chromosomes in human mammary carcinoma cells.

Chromosome G-banding analysis of two human mammary carcinoma cell lines, Elco and MCF-7, showed the existence of two X chromosomes in both cell lines. To determine the state of activity of the X chromosomes, a methylation-sensitive restriction endonuclease, HpaII, was used to distinguish the active X from the hypermethylated, inactive X chromosome with a probe for the phosphogalactokinase locus by Southern blot hybridization. DNA digested with the restriction enzymes PstI and BstXI showed a band at either 1.05 or 0.9 kilobases. After HpaII digestion, a 50% reduction in intensity was observed in the female controls, whereas total reduction of the band was observed for the tumor cell lines and the male control. This indicates the absence of an inactive X and the presence of only active X chromosomes in the mammary carcinoma cell lines and the male control. To investigate the mechanisms involved in the alteration of the X chromosome composition and activity, restriction fragment length polymorphism analyses of seven additional X chromosome markers (L1.28, DX13, p52A, pX65H7, L782, pA13.RI, and pXG-12) were performed on the DNA isolated from the tumor cells and controls. Heterozygosity for at least one of the seven markers was detected in the six female controls whereas only homozygosity was detected for each marker in the tumor cell lines and the male control. These results indicate that the two active X chromosomes identified in each of the two tumor cell lines are identical, resulting from duplication or nondisjunction of the active X and loss of the inactive X chromosome.

Blotting, Southern↗
PubMed1990

Transposition of the oncogene ets-1 in t(11;19) translocation in acute leukemia.

The specific chromosomal rearrangement t(11;19)(q23;p13) has been identified as a nonrandom chromosomal rearrangement in acute leukemia. The breakpoint, 11q23, coincides with the ets-1 oncogene locus. However, only very few studies have been done to verify the genomic alteration and transposition of ets-1 in the t(11;19) chromosomal rearrangement. In the present study, we identified the t(11;19)(q23;p13) translocation in two acute leukemic cases. One of the cases, biphenotypic leukemia, has been followed thoroughly. An abnormal karyotype was identified in the patient's blood and marrow samples at diagnosis and at relapse, while only normal karyotypes were identified at remission. In situ hybridization of chromosomal preparations with the ets-1 probe pHE5.4 resulted in silver grains nonrandomly localized to 19p13 in the metaphase spreads prepared from the blood sample taken at relapse, while no detectable grains were found on chromosome 19p13 in a sample taken at remission. To determine if genomic alterations of ets-1 are associated with this translocation, Southern blot hybridizations with the pHE5.4 probe were performed on deoxyribonucleic acid (DNA) isolated from blood or marrow samples of the patient at remission and relapse as well as on DNA from a disease-free normal control. Any DNA digested with AvaII, SstI, XbaI, and Bam HI, followed by hybridization with pHE5.4, demonstrated no genomic alterations or amplification of the ets-1 oncogene. Our study indicates that the ets-1 oncogene is transposed in the t(11;19) translocation without detectable alteration at the DNA level. The absence of ets-1 amplification in t(11;19) and its presence in the t(4,11) and t(9;11) translocations demonstrated by others suggests the possible existence of different molecular mechanisms involving the ets-1 oncogene in the pathogenesis of these leukemias.

Blotting, Southern↗
PubMed1990

Gas exchange across avian eggshells oscillates in phase with heartbeat.

Rahn et al. (J. Appl. Physiol. 69: 1546-1548, 1990) showed that the gas pressure in a plethysmograph containing an intact egg oscillates in phase with electrocardiogram (ECG) and that this pressure variation could be used as a noninvasive way to determine the heart rate of an avian embryo. One possible mechanism to account for the pressure oscillation is the mechanical movement of the embryonic heart, which leads to volume shifts of gas within the plethysmograph. Another possibility is that the oscillation of gas pressure with heartbeat is pulsatile gas exchange resulting from pulsatile blood flow. If gas exchange were transiently stopped, a pressure signal dependent on gas exchange should disappear, while a pressure signal dependent on cardiovascular motion should persist. Using a number of late-age hen eggs (at days 15-20 of incubation), we tested these hypotheses by suddenly changing the gas composition surrounding an egg and measuring the effect of the pressure oscillation. We found that 1) after 5% CO2-95% N2 was flushed into the plethysmograph (presumably halting gas exchange), pressure oscillations went almost to zero and the ECG signal remained; after air was flushed back to the plethysmograph, the pressure signal returned to control level; 2) after 20% CO2-20% O2-60% N2 was flushed into the plethysmograph (presumably increasing net gas exchange), the pressure signal increased 2.5-fold compared with that in air; and 3) after 1% CO2-99% N2 was flushed into the plethysmograph (presumably reversing gas exchange), the oscillation pressure decreased to one-fourth of that in air and the phase of pressure relative to ECG reversed compared with the phase in air.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pressure↗
PubMed1990

[Costs of dental care and medical care paid by the patients].

The National Health Insurance covers a minor part of the expenditures for adults' dental care in Norway. This paper describes the present principles for charging patients for health care services. The paper has 3 aims, 1) to describe patient charges assessed as personal expenditures for dental treatment, 2) to relate patient charges for dental treatment to patient charges for other health services, and thirdly 3) to compare the level of spending for dental care to other household-consumption. Patient charges are higher for dental care than for other non-institutionalized health services. There is an upper limit to patient charges for health services (dental services are not included). The upper limit was approximately 90 in 1987. Above that limit health services are free. Altogether 137,000 persons reached that level of personal expenditures for health services in 1987. The price per unit of dental services is considered rather low in Norway. However, approximately 600,000 adults had expenditures for dental services which exceeded 90. The inconsistency in the present level of patient charges is discussed.

Costs and Cost Analysis↗
PubMed1990

Modulation of rat Kupffer cells on high density lipoprotein receptors on hepatocytes.

The present study found that conditioned media from Kupffer cells preincubated with acetylated LDL or acetylated LDL and zymosan increased the number of HDL receptors on hepatocytes, using the method of conditioned media transfer. This indicated that the transferable factors produced by Kupffer cells modulate HDL receptors on hepatocytes.

Animals↗
PubMed1990

Epidermoid cyst of the spleen presenting as a generalized peritonitis.

In this report we reviewed 159 cases of epidermoid cyst of the spleen reported since 1929 and we added one case of our own with a unique clinical presentation. In these cases, the patients' age at presentation ranged from newborn to 51 years, with a mean age of 17.7 years. Female-to-male ratio was 2.0 to 1.0. Patients with this lesion usually present with asymptomatic abdominal mass and/or abdominal pain. Only in rare reports has there been infection (4 cases) or rupture (4 cases) of the cyst. In our case, the patient presented with an acute surgical abdomen and diffuse peritonitis. As in three of the previously reported cases associated with infection, Salmonella group organisms were cultured from the cyst abscess. Splenectomy is the surgical treatment of choice and the initial antibiotic regime should include Salmonella coverage.

Abscess↗
PubMed1990

[100,000 more adults visit the dentist: a few results of November 1989].

The aim of the present study was to describe the Norwegian adult population according to: 1. number of teeth present, 2. demand and utilization of dental services, 3. travel time from home to the dentist, 4. dental health behaviour, 5. fear for dental treatment. The analyses were performed on a set of national data collected in 1989, which was representative of the non-institutionalized Norwegian population 20 years and above. The sample size was 1260 individuals. About 75% of the people had 20 teeth or more present. Nine percent were edentulous. Seventy-seven percent who had demanded dental services during the last year. The average expenditure for dental treatment for those who had demanded the services during the last year was NOK 826. Fifty-three percent travelled 15 minutes or less from home to the dentist. Eighteen percent travelled 30 minutes or more. Almost everybody with their own teeth present brushed their teeth regularly once a day. Thirty-three percent of all dentate people used woodsticks regularly once a day, while 20% used toothfloss regularly. Seventy-five percent had no to mild fear of the dentist, while 7% had a strong fear. Fear of the dentist was higher among women than among men. Fear of the dentist decreased by increasing age. Few people, less than 4%, had cancelled a dental appointment because of dental anxiety. There has been an improvement in dental health and dental health behaviour in Norway during the 1970's and 1980's. These improvements are discussed with special attention paid to the findings from the present study.

Adult↗
PubMed1990

[A program for analysis of dose-response relationship with logistic model].

In order to avoid the defects in common methods for analysis of dose-response curves, we fit groups of dose-response curves simultaneously or separately on computer by using logistic model, with the EC50 and slope factor as the basic parameters. The pD2 and pA2 values were calculated from the best estimated EC50s. This method shows a good compatibility with the original experimental data. The BASIC program can be conveniently run on microcomputers.

Animals↗
PubMed1990

[Study on seasonality of 1-8 serotypes legionella pneumophila infections].

From March 1986 to May 1987, a seroepidemiological survey on seasonality of infection and transmission of legionella pneumophila serotypes 1-8 (Lp1-8) was performed among general populations in Wuhu area by cohort investigation (during spring and autumn, 203 paired sera), and in Nanjing area by monthly cross-sectional study (12 months, 1360 sera). The results showed that the seasonal prevalence peak of antibodies to Lp1-8 was in the summer and/or the autumn.

Adolescent↗
PubMed1989

Guanosine-5'-O-thiodiphosphate functions as a partial agonist for the receptor-independent stimulation of neural adenylate cyclase.

GTP-binding proteins (G proteins) have been implicated as mediators of several aspects of neuronal signal transduction including ion channels, phosphatidyl inositol turnover and the stimulation or inhibition of adenylate cyclase. Several investigators have employed the stable guanosine diphosphate (GDP) analog, guanosine 5'-O-thiodiphosphate (GDP beta S) to block putative G protein-mediated processes. Although GDP beta S is assumed to block G protein function, some investigators have reported partial activation of G protein-mediated processes by this compound. In this study we demonstrate that GDP beta S functions as a partial agonist for the adenylate cyclase system. In rat cerebral cortex membranes, GDP beta S activates adenylate cyclase with an EC50 similar to the hydrolysis resistant GTP analog, guanylylimidodiphosphate (GppNHp), but to a far lower extent. Further, GDP beta S antagonizes the activation of adenylate cyclase by high doses of GppNHp or GTP gamma S (another stable GTP analog) but potentiates adenylate cyclase activation by low doses of these nucleotides. High doses of GDP beta S provoke, only partially, exchange of nucleotides among G proteins, as measured by the transfer of the photoaffinity GTP analog, azidoanilido-GTP, between the inhibitory and stimulatory GTP-binding proteins. In the presence of the beta-adrenergic agonist, isoproterenol, GDP beta S fails to support stimulation of C6 glioma membrane adenylate cyclase and inhibits GppNHp- or GTP gamma S-mediated stimulation of that enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1989

Chromosomal evolution in the progression and metastasis of human malignant melanoma. A multiple lesion study.

In order to distinguish those chromosomal aberrations associated with tumorigenesis from those associated with tumor progression of malignant melanoma, chromosome analysis was performed on eight tumors derived from one patient. Three common marker chromosomes, a deletion of chromosome 1, a deletion of chromosome 9, and a translocation involving chromosomes 7 and 12, were identified in each tumor. The presence of common markers in these intrapatient tumors indicates the monoclonal origin of these tumors. Furthermore, the consistent and specific involvement of chromosome 9 in both interpatient and intrapatient studies suggests the crucial role that chromosome 9 plays during the development of human malignant melanoma. In addition to common markers, different overlapping markers including those involving chromosomes 2, 3, and 6, were also identified, suggesting that chromosomes 2, 3, and 6 are most likely associated with the progression, instead of the genesis, of the tumor. Finally, lesion-specific marker chromosomes were identified in each tumor indicating the nonrandom selection and modification of the metastatic process. The nature of chromosomal evolution among the eight tumors was clearly demonstrated by the retention and amplification of specific marker chromosomes, with the latter tumors containing more overlapping markers than the early tumors and the recurrence of identical markers in the different branches of evolution. One of the last three tumors obtained immediately before the death of the patient contained all the overlapping markers identified in other tumors, which may indicate that a plateau of chromosomal evolution of these tumors has been reached. These observations demonstrate a nonrandom or programmed chromosome evolution of human neoplasia that could be intrinsic to the aneuploid nature of neoplasia.

Chromosome Aberrations↗
PubMed1989

Carotid artery stump pressure: how reliable is it in predicting the need for a shunt?

Carotid artery stump pressure was measured in 84 cases of carotid endarterectomy. The operations were performed in 71 patients over a period of five years. An altered neurological status during temporary occlusion of the carotid artery, assessed with the patient under local anesthesia, was the sole criterion for shunt placement. Stump pressure (SP) was significantly higher in the 69 unshunted cases (mean of 53.3 mmHg) than the 15 shunted cases (mean of 34.2 mmHg). Shunt was required in two of 41 cases (5%) with SP of greater than 50 mmHg, eight of 36 cases (22%) with SP of 25-50 mmHg, five of seven cases (71%) with SP of less than 25 mmHg. The clinical presentation, including history of prior stroke, and the presence of contralateral disease (including complete carotid occlusion), did not influence the need for a shunt. In this series, carotid artery stump pressure has greater predictive value for shunt requirement when it is greater than 50 mmHg or less than 25 mmHg. However, monitoring the neurological status of the patient in the awake state is still the most reliable method of determining shunt requirement. In our experience, this is associated with minimal morbidity and no mortality.

Aged↗