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Biomedical subjects

A Toth

Publications and source records attributed to A Toth.

At least 19 recordsLinked to original sources
PubMed2001

QRS Score: a composite index of exercise-induced changes in the Q, R, and S waves during exercise stress testing in patients with ischemic heart disease.

BACKGROUND: To detect ischemic heart disease, the exercise-induced ST-segment displacement is the most frequently used ECG parameter. However, the value of this marker was proven to be limited with varying sensitivity and specificity. A new parameter, called QRS score, emerged to improve the efficacy of exercise testing. METHODS: Our study aimed at evaluating the diagnostic value of QRS score in ischemic heart disease, investigating males and females separately, and examining the effects of heart rate and antiischemic medication. QRS score and cumulative ST depression were calculated in 212 patients and correlated to the findings of the stress myocardial perfusion SPECT (197 subjects) or coronary angiography (54 subjects). RESULTS: An inverse correlation could be found between the QRS score and the results of myocardial SPECT and coronary angiography in the whole population, especially in males; females did not show a significant relationship. In patients with conclusive tests (achieving 85% of the maximal predicted heart rate) QRS score correlated significantly with the results of the stress myocardial perfusion SPECT and coronary angiography. The sensitivity, specificity, and validity of the QRS score surpassed those of the cumulative ST depression in the entire population as well as in patients with conclusive tests. The antiischemic medication did not affect correlation values. CONCLUSION: QRS score was significantly related to the extent of myocardial ischemia and the severity of coronary heart disease, thus along with the analysis of ST-segment displacement may contribute to the more precise evaluation of exercise testing.

Coronary Angiography↗
PubMed2000

A novel model for the in vivo monitoring of uterine microcirculation and intracellular free calcium changes in rat.

The aim of this work was to develop a model to study the microcirculation and relative levels of intracellular free calcium in the myometrium of pregnant rats. On Day 21 of gestation a lobe of uterus was prepared free, flipped over, and mounted in a superfusion chamber leaving the radix and thereby the innervation and circulation intact. RBC velocity and arteriolar diameters were determined by means of intravital video microscopy before and after stimulation (norepinephrine). To study intracellular free calcium changes, the fluorescent dye Indo-1 AM was added to the superfusate in the chamber. Fluorescence images were recorded and ratios of the images collected at 400 and 506 nm were calculated and changes thereof were assumed to represent intracellular free calcium changes. RBC velocity and arteriolar diameter did not change for at least 1 h, while the response to norepinephrine was similar at the beginning of the experiment and after 120 min. In four separate interventions, the uterus was challenged with 5 x 10(-4) IU/ml oxytocin, 4.5 mM calcium, 5 x 10(-4) IU/ml oxytocin with 4.5 mM calcium, and 5 microM ionomycin, resulting in an increase of the 400/506 nm ratio of 27, 31, 76, and 103%, respectively, representing a relative increase in intracellular free calcium. This novel in vivo model is suitable for monitoring intracellular free calcium changes and to record RBC velocities and blood vessel diameters in the myometrium of pregnant rats.

Animals↗
PubMed2000

Cohesin's binding to chromosomes depends on a separate complex consisting of Scc2 and Scc4 proteins.

Cohesion between sister chromatids depends on a multisubunit cohesin complex that binds to chromosomes around DNA replication and dissociates from them at the onset of anaphase. Scc2p, though not a cohesin subunit, is also required for sister chromatid cohesion. We show here that Scc2p forms a complex with a novel protein, Scc4p, which is also necessary for sister cohesion. In scc2 or scc4 mutants, cohesin complexes form normally but fail to bind both to centromeres and to chromosome arms. Our data suggest that a major role for the Scc2p/Scc4p complex is to facilitate the loading of cohesin complexes onto chromosomes.

Cell Cycle Proteins↗
PubMed2000

Marshall Urist Award. Interstitial collagenase gene expression correlates with in vitro invasion in human chondrosarcoma.

Matrix metalloproteinases contribute to the processes of local invasion and metastasis by providing cells with the ability to traverse tissue boundaries. The levels of gene expression were quantitated for matrix metalloproteinases-1 and tissue inhibitors of metalloproteinases-1 in human chondrosarcoma cell lines, and the results were correlated with cell differentiation, collagenase activity, and in vitro invasion. Three well characterized human cell lines were used in this study, with the level of chondrocytic differentiation confirmed to be JJ012, FS090, and 105KC in increasing order on the basis of aggrecan and collagen gene expression. The matrix metalloproteinases-1/tissue inhibitors of metalloproteinases-1 ratio correlated with the level of differentiation in an inverse fashion. Collagenase activity paralleled matrix metalloproteinases-1/tissue inhibitors of metalloproteinases-1 gene expression and was associated with a more invasive phenotype in an in vitro assay. In this report, matrix metalloproteinase-1 and tissue inhibitors of metalloproteinases-1 expression in human chondrosarcoma tumor cell lines were quantitated, and it was shown that interstitial collagenase gene expression correlates inversely with chondrocytic differentiation. Differences in collagenase activity and in vitro invasion correlate inversely with the level of differentiation. These findings are consistent with the hypothesis that collagenase activity is associated with a poorer prognosis in chondrosarcoma by facilitating cell egress from the tumor matrix.

Antineoplastic Agents↗
PubMed2000

Detection of chlamydial antigenic material in ovarian, prostatic, ectopic pregnancy and semen samples of culture-negative subjects.

PROBLEM: The pathogenesis of long-term sequelae in Chlamydia trachomatis infection is poorly understood. While serology indicates previous chlamydial infection, culture studies are frequently negative. We wanted to know whether in chronic cases the bacterium is absent or persists in a dormant state where it evades detection. METHODS OF STUDY: Using immunoperoxidase (IP) staining and in situ hybridization (ISH), we examined tissues of culture-negative subjects. Ovarian biopsy specimens from 19 culture-negative women with pelvic adhesions and/or tubal infertility were analyzed by both methods. Samples of prostates from 10 culture-negative men undergoing prostatectomy for benign hypertrophy, two sets of semen samples from culture-negative sexual partners of 28 women with PID and/or bacterial vaginosis (BV), and ten endometrium-tube sample-pairs from ectopic pregnancies (EPs) were examined by IP only. RESULTS: Seven of the nineteen ovarian specimens tested positive for Chlamydia antigen or deoxyribonucleic acid (DNA) (36%). Of the 10 hypertrophic prostates examined, 4 (40%) were positive. Of the 28 semen samples examined, 10 (35%) tested positive. Tissue samples of 3 cases of EP were positive by IP. CONCLUSIONS: 1. C. trachomatis antigen and nucleic acid can be frequently demonstrated in asymptomatic, culture-negative men and women with chronic infection. 2. Chlamydia antigens may have an etiologic role in benign prostate hypertrophy and EP. 3. Antigenic material may be sexually transmissible. 4. IP and ISH identify temporarily inactive bacteria that may continue to act as immunostimulants and potentially reactivate as Chlamydia infection.

Adult↗
PubMed1996

Are there oxygen-deficient regions in resting skeletal muscle?

The purpose of this study was to determine whether there are local regions in resting skeletal muscle in which the oxygen delivery is insufficient to support oxidative metabolism. This hypothesis was tested by stopping the blood supply to the exteriorized cat sartorius muscle for 5 min while monitoring NADH fluorescence in localized tissue areas 15-25 microns in diameter. A rise in fluorescence was taken to indicate a shift to anaerobic metabolism. Tissue sites in the arteriolar and venular regions of the capillary network were selected for study. After flow stoppage, fluorescence did not change for an average of 48 +/- 22 (SD) s and then rose over a period of 61 +/- 27 s to an average value 55 +/- 19% above control for arteriolar and venular sites combined. Fluorescence began to rise within 5 s of flow stasis in only 1 of 61 sites and within 10 s in 2 sites. There was no difference in the time course or magnitude of fluorescence changes at arteriolar and venular sites. The data indicate that in resting skeletal muscle, oxygen supply appears sufficient to support oxidative metabolism in over 95% of the tissue.

Animals↗
PubMed1995

The utility of a bilateral breast pumping system for mothers of premature infants.

Mothers of premature infants have difficulty maintaining their milk supply as a result of the separation that occurs between the mother and the baby. The hypothesis in the present investigation is that use of a bilateral (simultaneous) breast pumping system will increase the volume of milk expressed in these mothers. Thirty-two breastfeeding mothers of premature infants were randomly assigned to either the control (single) or the experimental (bilateral) breast pump group. Mothers pumped at least four times a day. Data collection included a daily milk production log, weekly serum prolactin levels, and a weekly State-Trait Anxiety Inventory (STAI). Participation lasted from four to six weeks. Data analysis included average STAI scores; average prolactin levels; and weekly averages for number of pumping sessions, hours of pumping, and milk production in milliliters. The two groups did not differ on several demographic characteristics, STAI scores, prolactin levels, number of pumping sessions per week, or weekly milk production. The amount of time spent pumping, however, was statistically less for mothers who used the bilateral pump (7.6 +/- 3.0 hours/week) versus those who used the single pump (11.1 +/- 3.1 hours/week) (p = .003). Although use of either the single pump or the bilateral electric pump resulted in similar milk production, the bilateral pump significantly reduced the time invested in pumping. Health professionals should advocate use of the bilateral pump for mothers of premature infants. Additional studies are needed to determine strategies for increasing milk production in this population.

Adult↗
PubMed1994

Protection of immunosuppressed mice against translocation of Pseudomonas aeruginosa from the gut by oral immunization with recombinant Pseudomonas aeruginosa outer membrane protein I expressing Salmonella dublin.

AroA Salmonella dublin was used as recipient for a plasmid coding for the outer membrane protein I (OprI) of Pseudomonas aeruginosa. Oral immunization of Balb/c mice with recombinant S. dublin induced serum IgG and IgA antibodies against P. aeruginosa. In spleen and Peyer's patches anti-P. aeruginosa IgG- and IgA-secreting cells could be measured by the ELISPOT technique. In an oral challenge of immunosuppressed mice with P. aeruginosa the orally immunized animals had a 58-fold higher LD50 than control animals.

Administration, Oral↗
PubMed1992

Sumatriptan injection is superior to placebo in the acute treatment of migraine--with regard to both efficacy and general well-being.

The efficacy of subcutaneous injection of sumatriptan in the acute treatment of migraine was assessed in a double-blind, randomized, placebo-controlled cross-over study of 27 migraine patients. In addition, the patients were asked to give information about their well-being and subjective symptoms by means of a self-administered standardized questionnaire. A total of 22 migraine sufferers received a subcutaneous (sc) injection of 8 mg of sumatriptan and 24 received placebo. Of these patients, 19 received both treatments and thus completed the study. The primary efficacy end-point was a reduction in headache severity from severe or moderate to mild or no headache at 30, 60, 90 and 120 min. An effective response to treatment was achieved within 30 min in 63% and within 60 min in 84% of patients when treated with 8 mg sumatriptan sc, compared with 11% for placebo (p less than 0.001). Sumatriptan also provided significant relief from nausea and photophobia as compared with placebo. The proportion of patients that needed rescue medication after 120 min was significantly lower (p less than 0.001) with active treatment when compared with placebo. Sumatriptan was well tolerated and the majority of adverse events were mild and transient. The most frequent symptoms were those of malaise/fatigue or numbness. No changes in blood pressure or ECG readings were observed during the treatment. Compared with placebo, subcutaneous 8 mg sumatriptan also caused a substantial improvement in general well-being as revealed by the Minor Symptoms Evaluation Profile-acute (MSEP-acute) questionnaire.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1992

A multipurpose instrument for quantitative intravital microscopy.

An in vivo microscope system has been developed that can measure fluorescence emission and/or light absorption at up to five wavelengths in a tissue area of 18-30 microns diam while imaging adjacent microcirculatory vessels with a video system. The system also incorporates a computer-controlled stage and data acquisition system for rapid and repeated measurements from a number of tissue sites. The tissue area monitored for fluorescence or absorption can be defined further by a confocal arrangement of the microscope optics. Tests of the system for NADH fluorescence measurements show good agreement between the fluorescence at 450 nm and NADH concentration in vitro and in skeletal muscle. The instrument can also be used simultaneously for spectrophotometric determination of O2 saturation and hematocrit in microcirculatory vessels. In vitro tests indicate suitable accuracy for such measurements. The open architecture and modular arrangement of the instrument facilitates its use for a variety of simultaneous measurements of parenchymal cell and microcirculatory function.

Animals↗
PubMed1991

Pharmacokinetics of ceftriaxone in liver-transplant recipients.

The disposition of ceftriaxone was studied after a single 2 g intravenous dose in seven patients 3 to 5 days after liver transplantation. Ceftriaxone concentrations in plasma, urine, and bile were measured by HPLC, and plasma protein binding was determined by equilibrium dialysis. Plasma protein binding was nonlinear, and the unbound fraction varied between 0.05 and 0.56. Both capacity and affinity were markedly different from reported values for normal subjects. The pharmacokinetic parameters obtained were: total body clearance (TBC), 11.2 +/- 7.8 mL/hr/kg total and 44.8 +/- 29.1 mL/hr/kg unbound; volume of distribution (V(area)), 224 +/- 76 mL/kg total and 767 +/- 432 mL/kg unbound; steady-state volume of distribution (Vss), 212 +/- 68 mL/kg total and 651 +/- 368 mL/kg unbound; terminal disposition half-life (t1/2), 21.6 +/- 14.3 hour total and 16.3 +/- 11.1 hour unbound. TBC for both total and free drug was considerably lower than literature values for normal subjects. V(area) for total drug was greater than normal, whereas the corresponding value for free drug was smaller than normal. The plasma ceftriaxone concentrations at 12 and 24 hours were above the reported minimum inhibitory concentration (MIC). The fraction of the administered dose excreted in urine over 24 hours was 38 +/- 29% and did not differ markedly from that reported for normal subjects. Less than 2% of the administered dose was excreted in 24-hour bile; however, biliary concentrations were always above MIC. Ceftriaxone can be administered once or twice daily at a dose of 2 g/day for prophylaxis in liver transplant recipients.

Adult↗
PubMed1986

Effect of antimicrobial agents on root surface caries, alveolar bone loss, and microflora in rice rats.

Two antimicrobial agents, 9-aminoacridine (0.2%) and minocycline (0.2%), were evaluated for their efficacy in inhibiting root surface caries, bone loss, and microflora in rice rats. A solution of 5000 ppm fluoride was used as a positive control for the inhibition of root surface caries, and double-distilled water was used as a negative control group. Each rat was treated by having its molar teeth swabbed 2 X per day with the prescribed agent in its group for nine weeks. Root caries reduction in the minocycline and fluoride groups was not significantly different, but the reduction was significantly greater than in the 9-aminoacridine group, with the caries score in all three groups being significantly less than that in the water control. Bone loss reduction for the minocycline group was significantly greater than that for any other group.

Alveolar Process↗
PubMed1986

Outcome of subsequent pregnancies following antibiotic therapy after primary or multiple spontaneous abortions.

The course of the subsequent pregnancy and the maternal and fetal complications were evaluated in 254 couples who were seen in an infertility clinic after primary or multiple spontaneous abortions. The 100 couples who were treated with antibiotics after pregnancy loss showed a significantly better chance of achieving a subsequent pregnancy. The outcome of pregnancy was significantly better in the antibiotic treated group and the rate of spontaneous abortion recurrence was significantly lower (10 versus 38 per cent). The number of maternal complications was significantly less in the treated group--premature rupture of membranes, three (4 per cent) versus 30 (46 per cent), and postpartum fever, three (4 per cent) versus 23 (35 per cent), respectively. The untreated group experienced a significantly lower percentage of vaginal delivery (56 versus 69 per cent) (p less than 0.001). In the antibiotic treated group, there were significantly lower rates of fetal complications, including fetal distress, meconium, respiratory distress syndrome, neonatal infection and hyperbilirubinemia. The mean birth weight of infants in the antibiotic treated group was significantly higher (3,529 versus 3,090 grams; p less than 0.001). Prematurity and postdatism were significantly less frequent in the antibiotic treated group, and the corresponding Apgar scores were significantly better. We, thus, postulate that certain spontaneous abortions may be caused by bacteria present in the genital tract at the time of conception. These bacteria may have an adverse effect on the course of pregnancy and result in increased maternal and fetal complications.

Abortion, Incomplete↗