摘要:

The mas oncogene receptor has been reported to confer angiotensin (Ang) responsiveness in NG115-401L neuronal cell line. To test if mas oncogene encodes an Ang receptor in peripheral tissue, Balb 3T3 and rat aortic vascular smooth muscle cells (VSMC) were cotransfected with a plasmid containing the mas oncogene (pSM422) and a plasmid expressing a selectable marker (pRSV-Neo). Transfected cells (Balb/mas and VSMC/mas) expressed the appropriate 2.4 Kb mas transcript, which was not present in parental cells. Both Balb/mas and VSMC/mas cells acquired Ang II and Ang III responsiveness as documented by Ang-stimulated increased [Ca2+]i. The ED50for these peptides were relatively high (4−6 × 10−5M). Ang III was approximately two times more potent than Ang II in stimulating45Ca efflux from Balb/mas cells, and its effect was not blocked by SarI, Ile8-Ang II. In contrast, substance P and a substance P analogue ([D-Arg1, D-Pro2, D-Trp7,9, Leu11] substance P) behaved as agonists, resulting in the stimulation of45Ca efflux and [Ca2+]iin Balb/mas cells without affecting control cells. The rank order potency for stimulating45Ca efflux in Balb/mas cells was substance P analogue»Ang III, substance P>Ang II. In summary, the authors show that although Ang III can stimulate biochemical events in mas transfected cells, which are known to be essential for Ang receptor signal transduction in other cell types, ie, [Ca2+]iand pHitransients, as well as inositol triphosphate formation, it did that at supraphysiological concentrations of the peptide.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The authors evaluated the in vitro and in vivo efficacy and photosensitizing effects of zinc deuteroporphyrin 2,4-bis glycol (ZnBG) as an inhibitor of adult Wistar rat tissue heme oxygenase (HO) activity and bilirubin production. Concentrations of 0.02-0.05 µM ZnBG inhibited the HO activity in postmitochondrial supernatants of liver, spleen, brain, and kidney by at least 50%. Administration of 4 jumole ZnBG/ kg body weight to adult rats significantly reduced the total body carbon monoxide (CO) excretion, an index of bilirubin formation, from 1 to 6 hours posttreatment. At 6 hours posttreatment, the HO activity in postmitochondrial supernatants of the liver and spleen, but not of the brain, was significantly lowered. ZnBG also behaved as an in vitro photooxidizer by degrading, in the presence of cool white light, the reduced form of nicotinamide adenine dinucleotide phosphate and histidine to CO and other nonidentified products. ZnBG also enhanced the natural photodegradation of bilirubin. Furthermore, administration of ZnBG to 1-day-old neonatal rats caused mortality within 12 hours in light-exposed animals, with a lethal dose 50 of 23 µM/ kg body weight.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The authors evaluated the assay performances and clinical usefulness of a newly developed solid phase radioimmunoassay (RIA) for total renin concentration (TRC) in human plasma. The direct total renin RIA was performed by a sandwich technique with a pair of anti-human renin monoclonal antibodies. Renin activation with trypsin did not change TRC. The RIA showed satisfactory assay performances and demonstrated full compatibility with a direct RIA-kit for active renin concentration (ARC) in human plasma. The values of TRC were 105.3 ± 8.6 pg/mL in normal subjects and 136.5 ± 14.6 pg/mL in patients with essential hypertension. The values of TRC and the ratios of ARC to TRC were high in patients with renovascular hypertension and were low in patients with primary aldosteronism. Although the TRC value in diabetic patients was 134.4 ± 14.8 pg/mL, the ratio of ARC to TRC was low. The RIA procedure was simple since prior purification or activation of renin was not required. These results suggest that the total renin RIA and its combined use with the active renin RIA may be helpful in understanding the renin-angiotensin system in human plasma.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The authors hypothesized that rat plasma or tissue glutathione metabolism could change with age due to possible decreases in glutathione- related enzyme activities. To test this hypothesis, the authors measured plasma and tissue concentrations of glutathione and glutathione- related enzymes. Animals were 3 months, 12 months, or 24 months old at the time of experiments. Plasma glutathione was found to be significantly increased in both the 12-month-old and 24-month-old groups compared to the 3- month-old rats. Tissue enzyme measurements showed no significant differences between the groups in lung or liver glutathione peroxidase or glutathione S-transferase. 7-Glutamyl transpeptidase activity was significantly decreased in kidney and lung with aging. Decreases in tissue 7-glutamyl transpeptidase activity occur with age; this may contribute to increases in plasma glutathione concentrations.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

To evaluate their policy of discontinuing broad spectrum antibiotics in patients with negative cultures who become afebrile but remain neutropenic, the authors retrospectively reviewed the charts of all pediatric patients diagnosed with cancer between 1980 and 1986. Two hundred seventy-one children had 385 admissions for infectious complications during the study period. In 39 of those episodes (9%), the patients had negative cultures, became afebrile, and were discharged with absolute neutrophil counts of<1000 cells/mm3 (mean 390 cells/ mm3). They received relatively short courses of antibiotics with a median duration of 4 days. Only four of these patients became febrile during the followup period and there were no fatalities. Given the benign course of these patients, recommendations for prolonged antibiotic courses should be reconsidered.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

In five separate sessions over a 13- month period, the authors monitored the handwashing habits of doctors, nurses, and other healthcare professionals in the nursery. Compliance rates regarding three specific items related to handwashing prophylaxis were noted by a group of observers without the knowledge of the subjects involved. Good handwashing prophylaxis was carried out by the doctors only 37.5% prior to handling infants, and 29.2% after contact with inanimate objects, whereas for these items the nurses complied 53.9% and 29.2%, respectively. Wrist ornaments were removed prior to handwashing in 72.7% and 75.3% of contacts. The data for other healthcare professionals were generally similar. The information from this study was used for educational purposes, which seemed to have had an impact on handwashing habits. The compliance rates during the later part of the study for the first two items combined improved from 28.4% to 62.6% (p<0.001). The authors conclude that in the newborn units, the compliance with handwashing is generally poor. They believe that with continued monitoring and educational efforts, it may be possible to improve habits regarding handwashing prophylaxis.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

The role of salivary epidermal growth factor (sEGF) in the maintenance of the esophageal mucosal mucus coat and its permselective properties was investigated for this study. Eighteen Sprague-Dawley male rats underwent sialoadenectomy (SAD), while 18 others with sham operation served as a control. Nine SAD rats in each group received EGF in a dose of 15µg/kg/d for five consecutive days prior to sacrifice. Esophageal mucosa dissected from the muscle layer was placed in the central port of a specially designed permeability chamber filled on both sides with equimolar solutions of NaCl or HCl (0.155 M). The rate of hydrogen ion diffusion from the mucosal to the serosal side was estimated by continuous recording of pH in the NaCl compartment. In addition, the mucosal mucus coat was evaluated by Alcian blue uptake methodology. SAD led to a 108% increase in the rate of permeability of the esophageal mucosa to hydrogen ion. Simultaneously, an 83% decrease in the mucus content on the surface of the esophageal mucosa was observed. A five-day supplementation of EGF substantially improved the permeability of esophageal mucosa (67%) and the mucous layer of esophagus (41%). sEGF seems to play an important physiological role in the maintenance of the functional integrity of the esophageal mucosa.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

Hereditary fructose intolerance (HFI) is a recessive genetic disorder with an estimated disease frequency of 1 in 20,000 and a carrier frequency of 1 in 70. Affected individuals are unable to assimilate fructose from fruit sugars and may develop severe hypoglycemia, metabolic problems, and death if misdiagnosed. Those who survive childhood learn to avoid sweets, effectively preventing further symptoms and complications. The disease is caused by a genetically defective hepatic enzyme, aldolase B. Traditionally, diagnosis has been made by intravenous fructose challenge or by liver biopsy, both difficult and risky invasive tests. Identification of mutations of the aldolase B gene by analysis of DNA from blood leukocytes is now possible, allowing for potential noninvasive diagnosis of subjects at risk in the future. The authors demonstrate heterozygosity for an aldolase B gene mutation in a patient with HFI.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

A 26-year-old ABO-O positive patient with aplastic anemia received a bone marrow transplant from his genotypically HLA identical, but ABO-A positive, brother. Engraftment of myeloid and megakaryocytic lineages occurred within 4 weeks but pure red cell aplasia and transfusion dependent anemia persisted for 160 days. The authors postulated that the failure of erythropoiesis was due to a high titer of anti- A isohemagglutinins. They tested this hypothesis with clonal cell cultures and flow cytometric analysis of ABO antigen expression by colony forming cells in vitro. During the period of prolonged red cell aplasia, the patient had normal numbers (85 ± 1 2 per 106cells) of circulating donor derived, burst forming units-erythroid (BFU-E). Immunophenotypic analysis of erythroid burst colonies derived from culture of the patient's bone marrow cells showed that 91 ± 5% of 274 nucleated red cells were A-antigen positive, confirming full donor engraftment. Autologous plasma and complement added on day 1 of culture did not affect the colony growth (82.5 ±15 per 106cells). However, when the addition of complement was delayed until day 7 of culture, there was 90% inhibition of BFU-E (7.5 ± 5 per 106cells) compared to controls (p<0.0004). Based on this, the authors propose a model for expression of ABO antigens during erythropoiesis, in which BFU-E do not express ABO antigens but their progeny do. The data support the hypothesis that the mechanism of prolonged pure red cell aplasia after ABO-incompatible bone marrow transplantation is complement mediated immune destruction of erythroid progenitors past the stage of BFU-E in differentiation.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID

摘要:

While acute splenic sequestration and splenic infarction are commonly observed in infants and young children with sickle cell anemia, they are rarely experienced by adult hemoglobin S homozygotes because the recurrent splenic infarction that takes place during childhood is typically followed by scarring, atrophy, and splenic fibrosis. Both acute splenic sequestration and splenic infarction do remain relatively common in adults with the other sickle hemoglobinopathies. These episodes are almost certainly a consequence of the persistently enlarged and distensible spleens that often remain present in these conditions. In this report, the authors describe two adult patients with hemoglobin SC disease: one who developed acute splenic sequestration and one with splenic infarction. In neither case was there a history of recent air travel or exposure to altitude. The clinical course of these two syndromes is presented, and the hematologic, radiologic, and pathologic manifestations are discussed. Because they can sometimes be difficult to distinguish from one another, and because a failure to identify acute splenic sequestration can be catastrophic, these two entities must be included in the differential diagnosis for any hemoglobin SC patient who present with an unexplained fall in hemoglobin, left upper quadrant pain, unexplained fever, or symptomatic splenomegaly.

ISSN:0002-9629    

出版商:OVID    

年代:1991

数据来源: OVID