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PubMed1992

Cholesterol palmitate in amniotic fluid: confirmation of a simple, rapid, inexpensive, and reliable indicator of fetal pulmonary maturity.

The cholesterol test was previously described and preliminary experience suggested it might be a rapid, inexpensive, and reliable indicator of fetal lung maturity. In this expanded series of 1342 patients delivered of infants within 72 hours of amniotic fluid analysis, the predictive value for mature test was 98.6%. Predictive value for immature test was 55.4%. For the phospholipid profile the predictive value was 97.0% for a mature test result, 31.2% for an immature result. These observations, coupled with its methodologic simplicity, make the cholesterol palmitate test a good first step in a cascade scheme of tests for fetal lung maturity and a valuable test in a facility where the phospholipid profile is not available 24 hours a day.

Amniocentesis↗
PubMed2001

The impact of requisition design on laboratory utilization.

Laboratory utilization by clinician specialty groups serving outpatients was monitored before and after requisition redesign. Requisition changes were designed to address compliance and utilization issues and included implementation of test groupings and cascades or ordering algorithms. Data collected included the number of selected tests and test sets ordered during both time intervals and the number of patient office visits. Selected tests for monitoring included CBC counts, metabolic panels, thyroid function tests, hepatic function tests, urine analysis, and send-out testing. Statistical significance was measured using Poisson rates for test ordering. The composite effect was a significant decrease in the overall number of tests ordered per outpatient visit for most specialties, with a shift in ordering practices from panels to individual tests. Utilization rates by specialty groups were characterized by average number of laboratory tests ordered per patient visit.

Clinical Chemistry Tests↗
PubMedDate not supplied

Leadership styles across hierarchical levels in nursing departments.

BACKGROUND: Some researchers have reported on the cascading effect of transformational leadership across hierarchical levels. One study examined this effect in nursing, but it was limited to a single hospital. OBJECTIVES: To examine the cascading effect of leadership styles across hierarchical levels in a sample of nursing departments and to investigate the effect of hierarchical level on the relationships between leadership styles and various work outcomes. METHODS: Based on a sample of eight hospitals, the cascading effect was tested using correlation analysis. The main sources of variation among leadership scores were determined with analyses of variance (ANOVA), and the interaction effect of hierarchical level and leadership styles on criterion variables was tested with moderated regression analysis. RESULTS: No support was found for a cascading effect of leadership across hierarchical levels. Rather, the variation of leadership scores was explained primarily by the organizational context. Transformational leadership had a stronger impact on criterion variables than transactional leadership. Interaction effects between leadership styles and hierarchical level were observed only for perceived unit effectiveness. CONCLUSIONS: The hospital's structure and culture are major determinants of leadership styles.

Adult↗
PubMed1986

Fetal maturity cascade: a rapid and cost-effective method for fetal lung maturity testing.

One hundred ninety-three amniotic fluid samples were tested for fetal lung maturity using a maturity cascade scheme involving the sequential use of, in order, the shake test, fluorescence polarimetry, and lecithin: sphingomyelin (L:S) ratio. If any of these tests indicated maturity, the sequence was terminated and no further test was performed, and the fetus was considered mature. Seventy percent of the tests yielded mature values and of these, 85 (63%) required a shake test only, 37 (27%) had a shake test and a fluorescence polarimetry, and only 14 (10%) required all three tests. From these 193 amniocenteses, 111 patients delivered within 72 hours of the procedure. One of 94 infants had respiratory distress syndrome after a mature test (1% false maturity) and ten of 17 had respiratory distress syndrome after an immature cascade (41% falsely immature). This approach saves time and cost and by confirming immaturity with multiple tests only when necessary and may improve predictability of neonatal respiratory distress syndrome.

Amniocentesis↗
PubMed1990

Methylprednisolone in high doses gives different effects on the early and the late part of complement.

The effects of methylprednisolone (MP) on endotoxin-induced activation of complement were studied in citrated pool plasma. Complement activation was tested in two immunoassays: one evaluating C3 activation fragments (C3act) and the other the terminal complement complex (TCC). These components are indicators of initial and terminal complement activation, respectively. Plasma samples were obtained at 1, 2, 4 and 6 h of incubation. Plasma containing endotoxin (2.10(9) ng/l) without MP revealed a marked increase of both C3act and TCC after 1 h. MP in high doses (10 mg/ml) gave an additive effect on activation of the initial part of the complement cascade compared to test plasma containing only endotoxin. In contrast, endotoxin-induced activation of the terminal part of the complement cascade was inhibited by the same dose of MP. The influence of lower doses of MP (0.1 and 1 mg/ml) on endotoxin-induced activation of complement was insignificant. Interestingly, MP without endotoxin induced activation of the initial part of complement. In test plasmas containing 5 and 10 mg/ml of MP (without endotoxin) marked increases of C3act values were seen. Despite this obvious activation of the early part of complement, only insignificant changes were found in TCC values. Test plasmas containing 0.1 and 1 mg/ml of MP revealed only minor changes in both C3act and TCC. In conclusion, the present study shows that high doses of MP activate the initial part of complement and that the endotoxin-induced activation of this cascade system was facilitated by MP. The terminal part of complement was, on the other hand, inhibited by high doses of MP.

Complement Activation↗
PubMed1997

Is fluorescence polarization reliable and cost efficient in a fetal lung maturity cascade?

OBJECTIVE: The objective of the study was to compare the accuracy of the TDxFLM test (Abbott Laboratories) with the fetal lung maturity cascade (shake, foam stability index, lecithin/sphingomyelin tests) and to determine whether the TDxFLM test could increase the efficiency and reduce the cost without decreasing the reliability of a cascade. STUDY DESIGN: A prospective, single-blinded study was conducted. Uncontaminated amniotic fluid obtained by transabdominal amniocentesis for fetal lung maturity assessment was evaluated with use of the fetal lung maturity cascade and the TDxFLM test. At study completion the results of the TDxFLM test were compared with those of the maturity cascade with regard to hyaline membrane disease, which was defined by strict clinical and radiographic parameters. A power analysis was performed requiring a sample size of 100 infants delivered within 72 hours of amniocentesis with use of the 95% confidence interval. RESULTS: A total of 115 cases had a full maturity cascade performed, of which 40 (35%) had a positive shake or foam stability index and 75 cases required progression to a lecithin/sphingomyelin ratio because of negative results. The TDxFLM test result was > or = 70 mg/gm in 42 (37%) of these 115. One hundred eight newborns were delivered within 72 hours of the amniocentesis; 65% (71) of these were between 30 and 37 weeks of estimated gestational age. There were 7 cases of hyaline membrane disease in the 108 newborns. Of these 108, 87 had a mature original cascade versus 85 mature tests with use of a proposed TDxFLM test-lecithin/sphingomyelin ratio cascade with one case of respiratory distress syndrome and hyaline membrane disease. The sensitivity, specificity, and positive and negative predictive values for the original cascade were 86%, 84%, 27%, and 99%, respectively; for the proposed TDxFLM test-lecithin/sphingomyelin ratio cascade the values were 86%, 83%, 26%, and 99%, respectively. The TDxFLM test-lecithin/sphingomyelin ratio cascade would have resulted in a cost reduction of 24% with no significant delay in turnaround time. CONCLUSION: The TDxFLM test appears to be a reliable and accurate assessment of fetal lung maturity. Furthermore, by replacing the shake and foam stability index portion of the cascade with the TDxFLM test, a cost savings of 24% would occur without a decrease in safety. These results also reveal that it could enhance patient care and be cost efficient for institutions not currently doing fetal pulmonary maturity testing to undertake use of the TDxFLM test and to only send out specimens for a lecithin/sphingomyelin ratio that have an initial immature TDxFLM test result (< 70 mg/gm). Likewise, institutions currently only performing a lecithin/sphingomyelin ratio may consider a TDxFLM test-lecithin sphingomyelin ratio cascade. Although direct costs would increase, they would be counterbalanced by a significant reduction in laboratory technician time.

Amniocentesis↗
PubMedDate not supplied

Neural interactions between cone photoreceptors and horizontal cells in the turtle (Mauremys caspica) retina.

Horizontal cells and cone photoreceptors in the vertebrate retina are interconnected by a complex network of synapses leading to the generation of color-coded responses in chromaticity horizontal cells. A simple cascade model of excitatory feedforward and inhibitory feedback synapses had been suggested to underlie these observations. In this study, the photoresponses of cones and horizontal cells were recorded intracellularly from the turtle eyecup. Three different approaches were adopted in order to test quantitatively the cascade model. Comparing linearity functions between these neurons indicated multiple excitatory inputs to each type of horizontal cells. The depolarizing photoresponses of R/G C-type horizontal cells were considerably faster than those of L-type horizontal cells but slower than those recorded from L-cones. This observation disagrees with the basic assumption of the cascade model that assign the depolarizing photoresponses of R/G C-type horizontal cells to a negative feedback pathway from L-type horizontal cells onto M-cones. Finally, the action spectra of each of the three types of horizontal cells could not be solely accounted for by input from one spectral type of cones. Only by assuming excitatory and inhibitory inputs from all spectral types of cones, the action spectra of all types of horizontal cells could be reconstructed. These findings suggest that the negative feedback pathways from horizontal cells onto cones in the turtle retina cannot solely account for the chromatic properties of the horizontal cells and support a direct inhibitory inputs from cones to turtle horizontal cells.

Animals↗
PubMed1996

Ex-vivo in-vitro inhibition of lipopolysaccharide stimulated tumor necrosis factor-alpha and interleukin-1 beta secretion in human whole blood by extractum urticae dioicae foliorum.

An extract of Urtica dioica folium (IDS 23, Rheuma-Hek), monographed positively for adjuvant therapy of rheumatic diseases and with known effects in partial inhibition of prostaglandin and leukotriene synthesis in vitro, was investigated with respect to effects of the extract on the lipopolysaccharide (LPS) stimulated secretion of proinflammatory cytokines in human whole blood of healthy volunteers. In the assay system used, LPS stimulated human whole blood showed a straight increase of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) secretion reaching maximum concentrations within 24 h following a plateau and slight decrease up to 65 h, respectively. The concentrations of these cytokines was strongly positively correlated with the number of monocytes/macrophages of each volunteer. TNF-alpha and IL-1 beta concentration after LPS stimulation was significantly reduced by simultaneously given IDS 23 in a strictly dose dependent manner. At time 24 h these cytokine concentrations were reduced by 50.8% and 99.7%, respectively, using the highest test IDS 23 assay concentration of 5 mg/ml (p < 0.001). After 65 h the corresponding inhibition was 38.9% and 99.9%, respectively (p < 0.001). On the other hand IDS 23 showed no inhibition but stimulated IL-6 secretion in absence of LPS alone. Simultaneously given LPS and IDS 23 resulted in no further increase. In contrast to described effects on arachidonic acid cascade in vitro, tested Urtica dioica phenol carbon acid derivates and flavonoides such as caffeic malic acid, caffeic acid, chlorogenic acid, quercetin and rutin did not influence LPS stimulated TNF-alpha, IL-1 beta and IL-6 secretion in tested concentrations up to 5 x 10(-5) mol/l. These further findings on the pharmacological mechanism of action of Urticae dioica folia may explain the positive effects of this extract in the treatment of rheumatic diseases.

Adult↗
PubMed1997

A branch in the ToxR regulatory cascade of Vibrio cholerae revealed by characterization of toxT mutant strains.

Co-ordinate expression of genes associated with pathogenicity in Vibrio cholerae requires two transcription activators, ToxR and ToxT. Work carried out to date suggests that ToxR activates transcription of the toxT gene and that ToxT directly activates transcription of several genes whose products play a role in colonization or CT production by V. cholerae. Previous work also suggests that ToxR can directly activate transcription of the CT operon (ctxAB) independently of ToxT, thereby implying a degree of complexity in control of the cixAB operon not found with other genes of the ToxR regulon. We tested the regulatory cascade model of virulence gene expression by constructing strains of classical and El Tor V. cholerae deleted for the coding sequence for the putative DNA-binding domain of toxT. Phenotypic analysis of these strains suggests that V. cholerae has ToxT-dependent and ToxT-independent branches of its virulence regulon. The results also raise questions about the precise role for ToxR in activation of ctxAB transcription.

Adhesins, Bacterial↗
PubMed1984

Personal air samplers for measuring occupational exposures to biological hazards.

Microbiological air samplers, designed to be worn as personal samplers, were evaluated for studying occupational exposures to aerosols of infectious and allergenic materials. Gelatin filter media, an impinger sampler, and spiral and cascade impactors were tested for collection efficiency for small (less than or equal to 2 microns) latex spheres and for recovery of bacterial aerosols. Only 20% of an aerosol of 0.8 micron latex particles passed through the impinger uncollected, while recovery of bacteria equalled or exceeded collection in an all-glass impinger. Gelatin filters matched the collection efficiency of membrane filters, but were unsatisfactory for the isolation of bacteria sensitive to dehydration. The spiral sampler and the cascade impactor provide information on the size distribution of collected particles, although, at present, collection efficiencies for very small particles are too low for rigorously quantitative studies. Methods of collection, and sampling strategies for biological aerosols are similar to those used for measuring exposures of workers to chemical and mineral aerosols; however, preparation of samples and identification of isolates may have to be referred to experts in the fields of bacteriology, virology, and mycology.

Aerosols↗
PubMed1985

Inhibition by thiamine tetrahydrofurfuryl disulfide (TTFD) of the arachidonic acid cascade-line activation as evidenced in the heart-lung preparation of the dog.

The effects of thiamine tetrahydrofurfuryl disulfide (TTFD) on the gradual increase in the coronary blood flow (CBF) inherent in the canine heart-lung preparation were studied. TTFD is a disulfide-type derivative of thiamine reported to have an antiinflammatory effect in experimental animals. Since it was found that the substance could reverse the gradual increase in CBF, the possibility that the reversal was brought about through an inhibition of activation of the arachidonic acid cascade-line was tested, examining the effects of this substance on the CBF increase produced by arachidonic acid (AA) and prostacyclin (PGI2). The vasodilator response to AA, which was barely detectable at the start of the experiment at which CBF was at a physiological low level, became potentiated as the gradual increase in CBF occurred, returning to the initial magnitude after TTFD, while the vasodilator response to PGI2 remained essentially unchanged during the entire course of the experiment. It was concluded that TTFD reversed the gradual increase in CBF in the HLP through the inhibition of the arachidonic acid cascade-line activation.

Animals↗
PubMed1997

Induction of the primary dorsalizing center in Xenopus by the Wnt/GSK/beta-catenin signaling pathway, but not by Vg1, Activin or Noggin.

The molecular nature of the primary dorsalizing inducing event in Xenopus is controversial and several secreted factors have been proposed as potential candidates: Wnts, Vg1, Activin and Noggin. Recent studies, however, have provided new insight into the activity of the dorsalizing region, called the Nieuwkoop Center. (1) The activity of this dorsalizing center involves an entire signal transduction pathway that requires maternal beta-catenin (Heasman, J., Crawford, A., Goldstone, K., Garner-Hamrick, P., Gumbiner, B., McCrea, P., Kintner, C., Noro, C. Y. and Wylie, C. (1994) Cell 79, 791-803). (2) A transcription factor with potent dorsalizing activity, Siamois, is expressed within the Nieuwkoop Center (Lemaire, P., Garrett, N. and Gurdon, J. B. (1995) Cell 81, 85-94). We have used these two properties of the Nieuwkoop Center to evaluate the dorsalizing activity of the four secreted factors Wnt8, Vg1, Activin and Noggin. The requirement for beta-catenin was tested by coexpressing a cadherin, which sequesters beta-catenin at the cell membrane and specifically blocks its intracellular signaling activity (Fagotto, F., Funayama, N., Gluck, U. and Gumbiner, B. M. (1996) J. Cell Biol. 132, 1105-1114). Induction of Siamois expression was detected by RT-PCR. Of the four growth factors, only Wnt was sensitive to inhibition of beta-catenin activity and only Wnt could induce Siamois expression. Therefore, Wnt is able to induce a bonafide Nieuwkoop Center, while Vg1, Activin and Noggin probably induce dorsal structures by a different mechanism. To order the steps in the Nieuwkoop Center signaling cascade, we have tested the relationship between beta-catenin and GSK, a serine-threonine kinase that has been implicated in axis formation in a step downstream of Wnt. We found that GSK acts upstream of beta-catenin, similar to the order of these components in the Wingless pathway in Drosophila. We have also examined the relationship between the Wnt/beta-catenin pathway and Siamois. We show that beta-catenin induces expression of Siamois and that the free signaling pool of beta-catenin is required for normal expression of endogenous Siamois. We conclude that the sequence of steps in the signaling pathway is Wnt-->GSK-->beta-catenin-->Siamois.

Activins↗
PubMed1998

[Cognitive impairment and cardiovascular disease risk factors. Project CASCADE Kraków. III. Assessment of cognitive function in elderly women and men (65-78 years old)].

There are commonly used simple tests for cognitive function that allow for rather superficial assessment in population based study. The goal of the paper was to present the results of cognitive function assessment in elderly men and women recruited from Polish rural population obtained using the battery of tests designed for the CASCADE Project and to assess the relations between the results of tests included in the battery. Studied group were 182 persons at the age of 65-78 years. The battery of tests included: MMSE, Stroop Test, Test Purdue Pegboard (TPP), letter-digit substitution test, word recall test (3 word lists including one with distraction), word fluency test and prospective memory test. The battery allowed for the assessment of short, semantic and prospective memory, attention, speed of perception and processing, word fluency and motoric function. The results of all tests were strongly correlated and indicated for a decreased cognitive function in men and women at the age of 65-78 years with low level of education. Decreased level of cognitive function could be related both to physiological ageing of the brain and to the presence of pathological process.

Aged↗
PubMed1987

The 14CO2 breath test: facilities and limitations of a rapid and noninvasive method for in vivo evaluation of modified hepatic cytochrome P-450--a critique.

By means of the breath test technique the cascade from O-demethylations to CO2 was investigated after pretreatment of mice with warfarin, phenobarbital, cobaltous chloride, sodium vanadate and metyrapone. It was the intention to examine the validity of the technique with respect to cytochrome P-450 activity. Therefore three different radioactive labeled substrates, i.e., hydrogen carbonate, formate and xenobiotics, were applied at three different levels of the one-carbon pathway and were utilized to demonstrate possible interference of the modifiers with the sequence from O-demethylation to CO2. Real in vivo information about a modified cytochrome P-450 system can be obtained using model substrates carefully selected with regard to the type of expected modification of the monooxygenase system. In addition, a parallel monitoring of the consecutive reaction sequence by measuring the conversion of formate to CO2 is necessary in order to guarantee the validity of the in vivo technique in visualizing the activity of the hepatic monooxygenase system.

Animals↗
PubMed1997

Inhibition of Fas-induced apoptotic cell death by osmotic cell shrinkage.

Apoptosis is an active physiological mechanism permitting the elimination of cells by triggering an intracellular signalling cascade. Here, we tested whether osmotic alterations of cell volume interfere with apoptotic cell death in Jurkat T-lymphocytes. Apoptotic cell death of Jurkat cells was elicited by activation of the Fas receptor which results in sphingomyelinase stimulation, release of ceramide, activation of Ras, Rac-proteins and formation of O2. Osmotic cell shrinkage inhibited apoptotic cell death induced by the Fas receptor in Jurkat T-lymphocytes. Osmotic cell shrinkage did not interfere with Fas induced activation of the acidic sphingomyelinase or activation of Ras but impaired the formation of O2 suggesting an important function of cell volume in the synthesis of reactive oxygen intermediates upon Fas receptor ligation.

Apoptosis↗
PubMed1985

A discrete mathematical model of unlabelled granulocyte kinetics. A preliminary study of feedback control.

The equations used in formulating the continuous model of granulocyte kinetics developed by O'Fallon et al. (1971) were analyzed to see if they could be altered to simulate a feedback mechanism operating on the production and development of granulocytes. After extensive study and modification of the continuous model, it was found that a discrete model based on a Leslie matrix procedure was more effective for simulating the feedback system. This discrete model was used to show experimentally, from a mathematical view point, that a feedback mechanism of some kind must be operating on the production and development of granulocytes. Further, the discrete model was subjected to preliminary tests (simultaneous and cascading feedback) to demonstrate that it has the capability of responding to feedback control.

Animals↗