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Biomedical subjects

K Simon

Publications and source records attributed to K Simon.

At least 73 records · Page 4Linked to original sources
PubMed1994

The natural history of postischemic T-wave inversion: a predictor of poor short-term prognosis?

BACKGROUND: This study followed up the natural history of T-wave inversion and assessed the short-term prognosis associated with the condition. METHODS: Forty patients with acute ischemic syndrome, without infarction, and with postischemic T-wave inversion (group 1) were followed during the persistence (inverted T-wave period) and after the resolution of T-wave inversion (positive T-wave period). Another 40 patients with acute ischemic syndrome, without infarction and with normal T waves (group 2), were also followed. RESULTS: Postischemic inverted T waves showed resolution within 3-21 days of presentation in 31 patients from group 1 on medical treatment alone. Further ischemic events (acute myocardial infarction, acute ischemic syndrome, angina pectoris, silent ischemia), inducible ischemia (during treadmill test), wall-motion abnormalities (demonstrated by echocardiography), all developing in the primarily ischemic myocardial area, were more frequent (P < 0.02) in group 1 patients during the inverted T-wave period compared with those experienced in the positive T-wave period of group 1 patients, and compared with group 2 patients. CONCLUSION: In most patients on medical treatment, postischemic inverted T-waves tended to resolve within 3 weeks. The presence of postischemic inverted T waves appears to be an independent marker of further ischemic events.

Adult↗
PubMed1994

Interferon and tumor necrosis factor responses of HIV+ patients as markers for monitoring of the AIDS progression.

The blood samples taken from 31 HIV+ and AIDS patients were used to study interferon (IFN) and tumor necrosis factor (TNF) responses. The IFN and TNF levels in plasma were determined. In the whole blood assay (whole blood diluted 1:10 with culture medium) Newcastle disease virus (NDV) and phytohemagglutinin (PHA) were used as cytokine inducers. Blood leukocytes of HIV+ patients produced significantly less IFN-alpha after NDV stimulation than the cells of healthy (HIV-) individuals. On the other hand, the production of IFN-gamma in response to PHA was impaired only in AIDS patients with stage CDC IV and CD4+ cell number < 200/microliters. These patients had also increased IFN levels in plasma. Particularly, the high level of IFN in plasma was frequently detected in patients with progressing AIDS with CD4+ cell number < 50/microliters. This type of IFN was identified as a mixture of acid-labile and acid-stable IFN-alpha. The IFN responses of HIV+ patients may be considered as markers for monitoring progression of AIDS and therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1993

[Postischemic inverted T waves: does gradual regression indicate improved prognosis?].

This study has followed up the natural history of postischemic inverted T waves and assessed the prognosis. 40 consecutive patients with unstable angina with postischemic precordial inverted T waves in the noninfarcted, previously ischemic area were followed during the persistence (negative T wave period) and after resolution of inverted T waves (positive T wave period). The outcome with frequencies of acute myocardial infarction, acute ischemic syndrome, angina pectoris, positive exercise test, silent myocardial ischemia, anterior wall motion abnormalities on echocardiogram, positive coronary arteriography were determined and compared in the negative versus positive T wave periods. Postischemic inverted T waves showed resolution within the postischemic 3-21 days (at a mean of 10.6 days) in 31 patients on medical treatment alone during the whole study period. Frequencies of parameters/patients determined in negative versus positive T wave periods are as follows: acute myocardial infarction: 5/40 versus 0/31 (non significant), acute ischemic syndrome: 25/40 versus 2/31 (p < 0.001), angina pectoris: 32/40 versus 11/31 (p < 0.001), positive treadmill exercise test: 14/16 versus 14/30 (p < 0.02), silent myocardial ischemia: 14/14 versus 16/31 (p < 0.01), hypokinesis 26/34 versus 4/24 (p < 0.001), positive coronary arteriography: 4/4 versus 11/11 (non significant). In most patients on medical treatment, the postischemic inverted T waves tend to resolve within 3 weeks. Attention has to be paid to the patients with postischemic inverted T waves during the negative T wave period: the high ischemic risk gradually decreases with resolution of negative T waves.

Angina, Unstable↗
PubMed1993

Effect of intravenous infusion of ranitidine on intragastric acidity in fasting subjects: comparison with bolus or Gastrojet (pH-stat-adjusted) infusion.

This study was undertaken in nine fasting healthy volunteers to compare the effect of intravenous continuous infusion versus bolus injection of ranitidine on 12-h intragastric pH, and to compare the efficacy of these two modes of administration of pH-stat-adjusted infusion of ranitidine using the Gastrojet. Each volunteer had three study sessions with 12-h pH measurements. In the ranitidine infusion treatment arm (RAN-INF), ranitidine was continually infused intravenously using an IVAC-pump at a dose of 0.125 mg mg.kg over a 12-h period. In the ranitidine bolus treatment arm (RAN-BOL), ranitidine bolus 50 mg was given over 10 min, every 6 h. When ranitidine infusion was given by the pH stat method using the Gastrojet (RAN-JET), sufficient ranitidine was given to maintain a present value of pH > or = 5. The study was analysed with a 3 x 3 Latin square cross-over design with multiple measurements of each phase of the cross-over. No difference was found between RAN-INF and RAN-BOL in 12-h or in daytime (10.00-18.00 h) mean pH, median pH, or percentage of pH > or = 5. Using RAN-JET, 89.5% of the pH values were > or = 5., compared with 39.7% and 40.0% with RAN-INF or RAN-BOL. RAN-JET also gave higher (P < 0.05) mean and median 12-h or daytime pH values, as compared with RAN-INF or RAN-BOL. The mean doses of ranitidine given in the 12-h infusion periods were 100 mg, 109 mg and 112 mg (RAN-BOL, RAN-INF and RAN-JET, respectively). Thus, this superior inhibition of acid inhibition achieved with Gastrojet does not require higher mean doses of ranitidine. These findings cannot necessarily be applied to persons with duodenal ulcer disease or to patients in an intensive-care unit setting. However, the data do raise the possibility that much greater inhibition of acid inhibition can be achieved by individualizing the dose of ranitidine using the Gastrojet.

Adult↗
PubMed1993

Perceived stress of nonhospitalized children during the hospitalization of a sibling.

The purpose of this research was to examine nonhospitalized children's perceptions of the stress of the hospitalization of a sibling. The subjects were 45 nonhospitalized children (5-12 years of age), and their parents, who had a sibling hospitalized over 24 hours for a medical or surgical condition. The Child Drawing: Hospital (CD: H) was used to measure the perception of stress related to a sibling's hospitalization. The nonhospitalized children perceived the stress of hospitalization at a level of stress (anxiety) equal to the level of stress of hospitalized children and higher than children in a school setting found by previous investigators. Sex and age were not related to the degree of perceived stress (anxiety). The perception of stress varied significantly in relation to the type of sibling relationship, residence of the well sibling during the hospitalization, frequency of sibling visitation, and amount of parental behavior change as identified by the nonhospitalized children.

Adaptation, Psychological↗
PubMed1992

p53 mutations in human lung tumors.

Mutation of one p53 allele and loss of the normal p53 allele [loss of heterozygosity (LOH)] occur in many tumors including lung cancers. These alterations apparently contribute to development of cancer by interfering with the tumor suppressor activity of p53. We directly sequenced amplified DNA in the mutational hot spots (exons 4-8) of p53 in DNA samples from 40 lung cancers. Most (31 of 40) samples were preselected for LOH in the region of p53. We detected 23 p53 mutations within these exons in 22 lung cancers; no p53 mutations were found in normal tissue of the patients. One-half of the mutations were G to T transversions on the nontranscribed strand, consistent with mutagenesis by tobacco smoke. Mutations of C to A on the nontranscribed strand, which would result from G to T mutations on the transcribed strand, were detected only in one sample. Three of 23 mutations were nonsense mutations; to date, nonsense mutations of p53 have not been reported in lung cancer. Mutation of this p53-coding region was detected in 20 of 27 small cell lung cancer samples, representing a 70% occurrence. Mutation of the p53 gene is apparently very frequent in small cell lung cancers. When LOH in the p53 region could be determined, complete concordance occurred between a sample having both a p53 mutation and LOH in the region of p53 (18 of 18 samples). Twelve samples of lung cancer had LOH in the region of p53, but the samples had no detectable p53 mutations, suggesting either alterations outside the known mutational hot spots of p53 or alterations of another unidentified tumor suppressor gene in the region of p53.

Amino Acid Sequence↗
PubMed1992

Tolerance of self induced in thymus organ culture.

F liver protein occurs in serum at low concentration, and therefore induces tolerance of self only in T cells. T cells which mature in cultured thymus lobes in the absence of this protein become reactive towards it but can be prevented from doing so by exposure to the protein while in culture. The threshold of tolerance induction for this soluble antigen is estimated in this way at approximately 1 microgram/ml, which is slightly less than the threshold of response of primed T cells in a proliferation assay. Freshly isolated thymocytes do not display reactivity to self-F protein, indicating that T cells normally become tolerant while still within the thymus.

Animals↗
PubMed1992

[Treatment of chronic hepatitis B with interferon alpha (Wellferon) with and without previous corticosteroid therapy -- results of a multicenter, double blind study].

The present study was aimed to test the efficacy and safety of interferon alpha (Wellferon-Wellcome Foundation Ltd.) either alone, or in combination with short-term corticosteroid pretreatment in the therapy of chronic hepatitis B. 44 patients with documented chronic hepatitis type B (12 women and 32 men; mean age 37.5 years, range 23-59 years) and satisfying the entry criteria were subjects of the study. 30 patients had chronic active hepatitis on liver biopsy, while 14 had chronic persistent hepatitis. Consecutive patients were given either placebo or prednisone in a double-blinded manner for 4 weeks (0.6 mg/kg/day in the first two weeks, 0.45 mg/kg/day in the third week and 0.25 mg/kg/day in the last week), and then, after a 2 week pause, therapy with interferon was instituted for a total of 12 weeks. Interferon was given by intramuscular injection in a single daily dose of 10 x 10(6) IU for 5 days and three times weekly thereafter. However, because of side effects, the dose of interferon was occasionally reduced to 5 x 10(6) IU in most patients. Interferon induced a sustained cessation of HBV replication as judged by loss of DNA-polymerase activity in 26 (59%) patients, 20 (45%) patients seroconverted to anti-HBe. Additionally, 6 (14%) cases lost HBsAg and seroconverted to anti-HBs. Prednisone pretreatment did not seem to improve the efficacy of interferon therapy. The outcome of the treatment was unrelated to gender and pretreatment activity of transaminases, however, patients with low activity of HBV replication were more likely to respond to therapy than patients with high HBV replication.

Adult↗
PubMed1992

[Study of selegiline and related compounds with x-ray diffraction].

Selegiline and its parent compounds were studied by X-ray diffraction. It was established that the racemates of primary and secondary amines (p-fluoro-amphetamine, methamphetamine, p-fluoro-methamphetamine) hydrochloride do not form racemic compounds but crystalline as conglomerates, at the same time tertiary amines like selegiline and p-fluoro-selegiline hydrochlorides do. The crystalline structure of five enantiomeric hydrochlorides were determined, the CPhe-C-C-N torsion angle is anti-periplanar in all cases but in p-fluoro-amphetamine where it is gauche.

Amphetamines↗
PubMed1991

Expression of c-jun during macrophage differentiation of HL-60 cells.

Cellular transcription factors are important in the regulation of cellular genes. Recent studies have indicated that a class of cellular genes known as early response genes are important in the control of cellular growth properties. Two of these genes, c-jun and c-fos, play an important role in the control of cellular differentiation. Because the acute myelogenous leukemia cell line, HL-60, is capable of differentiating to either macrophages or granulocytes, it provides a good model to understand differential gene expression. To determine if the modulation of c-jun was important in the differentiation of HL-60 cells to either macrophages or granulocytes, expression of c-jun mRNA was determined by Northern analysis at various times following treatment with a variety of differentiating agents, including 12-tetradeconyl-phorbol 13-acetate (TPA), retinoic acid (RA), dimethyl sulfoxide (DMSO), or 1,25 dihydroxyvitamin D3 [1,25 (OH)2 D3]. Both TPA and 1,25(OH)2D3, which induce HL-60 cells to differentiate to macrophages, resulted in marked increases in c-jun mRNA; while RA and DMSO, which induce HL-60 cells to differentiate to granulocytes, did not greatly alter c-jun mRNA expression. HL-60 cell lines resistant to macrophage differentiation after exposure to either 1,25(OH)2D3 or TPA did not result in increases in c-jun mRNA. These results suggest that elevation of c-jun mRNA in HL-60 cells correlated temporally with differentiation to macrophages. Thus, c-jun may be a critical cellular transcription factor involved in macrophage differentiation.

Calcitriol↗
PubMed1991

[Significance of the ECG in the diagnosis of so-called "stunned myocardium"].

The common feature of these 3 case reports can be characterized by the negative symmetric giant T waves developing 1-2 days after an acute myocardial ischemic attack, producing no enzymatic evidence of necrosis, persisting for several days or some weeks. The negative transient T waves are considered to fulfil neither the classical electrocardiographic characteristics of acute or chronic myocardial ischemia nor the criteria of subendocardial necrosis, but are believed to designate the existence of myocardial stunning. The authors suggest, that transient Q waves having been declared as the only electrocardiographic marker of myocardial stunning, reflect severe "transmural stunning" and can be detected relatively rarely, for a short time. In contrast, the transient negative T waves reflect "subendocardial stunning" and can be documented more frequently, persist for a longer time, and therefore could be a simple and sensitive method in detection of myocardial stunning.

Adult↗
PubMed1991

The effect of D-penicillamine on CCl4-induced experimental liver cirrhosis.

The effect of D-penicillamine (Pe) on liver fibrosis-cirrhosis induced by chronic CCl4 and phenobarbital (Pb) administration in Fischer 344 male rats was studied. Morphometric analysis did not reveal a decrease in the amount of connective tissue fibers after Pe-treatment. Compared to the CCl4 and Pb-treated control groups, Pe had no significant effect on the concentrations of hydroxyproline, a parameter of collagen degradation, either; however, it increased the glycosaminoglycan concentrations. Lymphocyte stimulation by Con-A in the Pe-treated groups did not differ from that of the CCl4 and Pb-treated ones. According to our studies, Pe-treatment was ineffective in rats with liver fibrosis-cirrhosis induced by CCl4 and Pb administration. It seems that Pe can be effective only in the cirrhosis types accompanied by a considerable copper accumulation due to suppression of the toxic effects of copper.

Animals↗
PubMed1991

Liver damaging effect of suramin in normal and carbon-tetrachloride treated rats.

Male Fischer 344 (F344) rats were treated with phenobarbital + carbon tetrachloride (CCl4) for 16 weeks to induce liver cirrhosis. Another group of rats received 50 mg/kg iv suramin once a week for 16 weeks. The third group of rats was treated with both phenobarbital + CCl4 and suramin. After 16 weeks of suramin treatment, a massive periportal infiltration composed of macrophages, many of them containing glycosaminoglycans in their cytoplasm, mast cells, and other inflammatory cells were observed. This lesion was added to the liver cirrhosis caused by CCl4 in the group treated with suramin and CCl4. The changes in glycosaminoglycan metabolism caused by suramin did not influence the CCl4 cirrhosis. Since suramin has been reported to be a prototype of a new generation of antitumor compounds, we suggest caution in the use of chronic suramin treatment, especially in patients with livers which are already damaged.

Animals↗
PubMed1991

[Clinical characteristics of patients with AIDS treated at the Infectious Disease Clinic, Medical Academy, in Wrocław during the years 1989-1990].

In the period 1989-1990 15 patients with various stages of HIV infection were treated. Among them were: 8 (53.3%) i.v. drug users, 6 (40%) homo- and bisexual men, and 1 (6.1%) woman with post-transfusion infection. The undertaken medical and laboratory examination, on the basis of CDC/WHO criteria, revealed: 6 patients with PGL, 6-with IV A stage, 1-IVB, 1-IVd and 1-IVE. The group of homo and bisexual men had lover CD4 lymphocyte counts than other patients. From our group only 7 patients were treated unsuccessfully with Retrovir (600 mg daily/6 months) but without side effects. Three patients died to this day.

Acquired Immunodeficiency Syndrome↗