Violet/blue light activates Nrf2 signaling and modulates the inflammatory response of THP-1 monocytes.

Several studies suggest that light in the UVA range (320-400 nm) activates signaling pathways that are anti-inflammatory and antioxidative. These effects have been attributed to Nrf2-mediated upregulation of "phase 2" genes such as heme oxygenase-1 (HO-1) that neutralize oxidative stress and metabolize electrophiles. Proteomics analysis previously had shown that small doses of blue light (400-500 nm) increased levels of peroxiredoxin phase 2 proteins in THP-1 monocytes, which led to our hypothesis that blue light activates Nrf2 signaling and thus may serve as an anti-inflammatory agent. THP-1 monocytes were treated with doses of blue light with and without lipopolysaccharide (LPS) inflammatory challenge. Cell lysates were tested for Nrf2 activation and HO-1 production. Treated cells were assessed for viability/mitochondrial activity via trypan blue exclusion and MTT assay, and secretion of two major pro-inflammatory cytokines, interleukin 8 (IL8) and tumor necrosis factor alpha (TNFα) was measured using ELISA. Blue light activated the phase 2 response in cultured THP-1 cells and was protective against LPS-induced cytotoxicity. Light pre-treatment also significantly reduced cytokine secretion in response to 0.1 µg ml-1 LPS, but had no anti-inflammatory effect at high LPS levels. This study is the first to report these effects using a light source that is approved for routine use on dental patients. Cellular responses to these light energies are worth further study and may provide therapeutic interventions for inflammation.

[Morphological description of distraction regenerates in children with congenital and acquired defects and facial skeleton bones hypoplasia].

Results of the morphological study of regenerates received after distraction upper and lower jaws in children were described. It was established that maternal bone and regenerate (retention during 3 months) in children of different age groups varied according to the stage of their structures differentiation; regenerate bone tissue was always less mature than maternal bone irrespective of its localization; lag in differentiation of new growth regenerate bone structures in the group of patients with congenital pathology if compared with the same indicator in the group of children with acquired pathology.

Assessment of fetal lung maturity. Practice parameter.

Despite the development of artificial surfactant and advances in respiratory support, respiratory distress syndrome (RDS) remains a major clinical concern. The relatively low prevalence of RDS requires test methods with very high diagnostic sensitivity and specificity for fetal lung maturity (FLM). Such methods often require sophisticated instrumentation, skilled staff, and long analytic times. This practice parameter discusses the usefulness of widely available methods and reaches several conclusions: (1) A satisfactory specimen of amniotic fluid is essential for effective laboratory assessment of FLM. (2) No test is immune from analytic interferences. (3) The lecithin/sphingomyelin (L/S) ratio or phosphatidylglycerol (PG) by thin-layer chromatography are unnecessary as obligatory panel components. (4) Either fluorescence polarization or lamellar body number density is an acceptable initial screening test. If maturity is indicated, no further testing is generally necessary. (5) If the result of the initial test in no. 4 is below but near the maturity criterion, the second rapid test usually can offer resolution; if the result is still immature, a third rapid test can be added (PG by Amniostat-FLM). (6) In the setting of poorly controlled diabetes, PG assessment by Amniostat-FLM should be performed to rule out false maturity predictions by the other rapid tests. Nevertheless, RDS will not develop in most fetuses in whom PG is not detected. (7) Clinical judgment remains the single most important criterion for fetal delivery.

The laboratory assessment of fetal lung maturity.

The assessment of fetal lung maturity by laboratory methods is reviewed, and the utility of the various approaches in the prediction of respiratory distress syndrome is discussed. Because of the relatively low prevalence of respiratory distress syndrome, methods with exceptionally high diagnostic sensitivity and specificity are required; such methods are rarely available for any diagnostic evaluation, and the methods with the greatest clinical acceptance in assessing fetal lung maturity have been those which require the most personnel time and skill. The consequences of laboratory testing in the environment of low prevalence diseases is discussed. Because of the clinical implications of an erroneous determination of fetal lung maturity, particularly in the case of incorrectly assessing the fetal lungs to be mature, a strong emotional overlay exists for accepting only the "reference method" or "gold standard" in this determination. This review briefly discusses the utility of commonly used methods in the context of the physical and chemical concepts. By reviewing the underlying principles of the methods, the origins of some of the frequently observed problems in this field are revealed. The emphasis is on practical application and issues of use both to clinician and laboratory in approaching this controversial and difficult area of assessment. It is demonstrated that there are several reasonably straightforward approaches which will provide appropriate clinical information more quickly, easily, and inexpensively than the methods generally requested.

Kinetics of bilirubin photodegradation with application to amniotic fluid.

By spectrophotometric methods we have studied the photodegradation of bilirubin in simple solution and in amniotic fluid and have found that: (1) the photodegradation process can be described by kinetics which are first-order in concentration and second-order in time; (2) the photodegradation products of bilirubin do not prevent the determination of the absorbance of the parent compound; (3) although the rate of the photodegradation process depends upon both the oxygen partial pressure and the irradiation intensity, the determination of the original bilirubin absorbance is independent of both of these parameters so long as they are constant over the period of photodegradation; (4) other chromagens in amniotic fluid (including hemoglobin and methemoglobin) experience little photodegradation in the time required to degrade bilirubin; (5) several absorbance measurements over a short (approximately five-minute) period of photodegradation are sufficient for the determination of the original bilirubin absorbance for the complete range of interest in amniotic fluid with an accuracy of about five percent.

Automatic calculation for the renal failure diet.

A logical scheme for algorithm for computation of the renal failure diet is presented along with its application to a programmable calculator. The program is user-interractive; the user may add or delete foods without re-entering previous data. Program outputs include water, protein, calories, carbohydrate, sodium, potassium, calcium, phosphorus, and the essential amino acids (EAA) in absolute and percentage terms. As an index of relative protein quality, the chemical score is computed on a meal-by-meal basis. Individual EAA scores are available to permit designation of the limiting EAA of a meal. A major benefit of the program is the ability to explore and document rapidly a wide variety of meal plans. Improvements in "user-friendliness" will facilitate application with patients.

Essential amino acid reference profile affects the evaluation of enteral feeding products.

The chemical score is a measure of the predicted metabolic usefulness of a protein in a food based on the comparison (ratio or percentage) of the concentrations of the essential amino acids (EAAs) to a "profile" assumed to reflect the true needs of the body. The score for the limiting EAA is taken to represent the value of the food. Such a chemical score is particularly useful for therapeutic diets where bioassay (such as nitrogen-balance studies) in a large number of patients may be unethical or impractical. Although a major limitation to the chemical-score method previously was scarcity and/or imprecision of data about EAA concentrations in foods, this situation has been mitigated by modern analytic methods. The validity of a chemical score is also exquisitely sensitive to the EAA profile used for comparison. Chemical scores published for a variety of enteral and parenteral feeding products implied a low (approximately 50%) protein value. These computations were based on the EAA profile of egg protein. This pattern is sufficient, in most cases, for body needs, but it may be far more than is necessary. Recently published profiles, based on measurements in human beings of actual protein and EAA requirements, point to a more realistic chemical-score computation. These profiles accommodate age and lifestyle factors and provide greater flexibility in the formulation of therapeutic diets.

Assessment of fetal lung maturity by laboratory methods.

I have reviewed many of the methods available for the assessment of fetal lung maturity. The difficulty of using diagnostic tests for diseases of low prevalence has been discussed. By reviewing the nature of the amniotic fluid surfactant material, and some of the principles underlying analytical methods, the bases of some of the recurring methodologic problems have been pointed out. It is concluded that a number of reasonably straightforward tests will provide information of essentially the same utility as more costly, difficult, and time-consuming assays commonly employed.

Cardiac energy considerations during intraaortic balloon pumping.

Cardiac oxygen availability and oxygen consumption were used in a theoretical study as indexes of myocardial energy supply and utilization, respectively. A detailed computer simulation of the closed-loop canine cardiovascular system was utilized to study the dependence of these indexes on timing of the intraaortic balloon pump. Oxygen availability exhibited higher sensitivity to balloon timing than oxygen utilization. While maximum augmentation of oxygen availability was 58 percent, oxygen consumption could be reduced by only 13 percent. Animal experiments were initiated to validate the theoretical results. The results of both the animal experiments and the computer simulation suggested that neither balloon timing which maximizes oxygen availability nor timing which minimizes oxygen consumption correlates with timing which minimizes aortic end diastolic pressure. Thus, end diastolic pressure, presently used as a determinant of proper timing in patients undergoing cardiac assistance, was found to be a poor index of ventricular energy consumption. A performance index comprised of clinically available variables, was formulated to reflect myocardial energy balance. In this performance index, mean diastolic pressure was used to represent energy availability and peak systolic pressure was used as an index of oxygen consumption. Their relationship to oxygen balance and their dependence on timing were studied using the computer simulation of the canine cardiovascular system and animal experiments. Theoretical and experimental results suggest that such an index is capable of representing O2 balance and can be used to control phasing of the device.

Optimal controller for intraaortic balloon pumping.

An optimal control algorithm was adapted to identify and track the optimal deflation time of the intraaortic balloon pump (IABP). Routines for handling physiologically imposed constraints were added to the algorithm which was implemented in a computer-controlled system. The system was designed to provide real time optimization for the clinical setting. The controller continuously maximizes a performance index while observing the constraints. The index is composed of clinically available hemodynamic variables which indicate changes in myocardial energy balance. Proper values for the algorithm parameters were determined and the system was tested in animal experiments. The results indicate that controlling deflation time relative to the R wave, which precedes the next ejection phase, reduces the time required for optimization when the heart rate varies.

Early absorption of enteral ranitidine after major laparotomy.

Thirty-six patients were studied following abdominal aortic surgery to determine if a commonly used medication could be absorbed from the gastrointestinal (GI) tract in the early postoperative period. Patients were randomized into two groups: Group I received ranitidine elixir 3 mg/kg via nasogastric tube every 12 hours; Group II received intravenous (IV) ranitidine 1 mg/kg every 8 hours. Ranitidine serum levels were measured with high performance liquid chromatography 1 hour after administration of the first three doses. Gastric pH was measured every 4 hours. It was found that serum ranitidine levels generally regarded as clinically effective were achieved in both groups. Although the levels were significantly higher following intravenous (IV) administration (Group II), there were no differences in average gastric pH. The authors conclude that within 24 hours of aortic surgery enterally administered ranitidine is effectively absorbed and provides prophylaxis equivalent to IV administration of the drug at lower cost. Other medications might be deliverable via the GI tract in the early postoperative period.

The effect of hemolysis on creatine kinase determination.

Hemolysis can cause falsely elevated creatine kinase (CK) values when spectrophotometric methods of measurement are used. This apparent increase in CK is due to the red blood cell enzyme adenylate kinase. In an attempt to reduce this interference, most commercial CK kits employ adenosine monophosphate and/or diadenosine pentaphosphate as adenylate kinase inhibitors. To determine whether hemolyzed specimens should be accepted for testing, we measured the CK values of 26 serum samples, each with six different concentrations of added hemolysate. The results showed that hemolysis had an additive effect on CK, with an average increase in CK of approximately 10 U/L for every 1 g/L of hemoglobin. In most settings, this increase is not clinically significant. In the case of massive hemolysis, the hemoglobin concentration of the serum can be measured to correct the apparent CK value. The exclusion of hemolyzed specimens is unnecessary.

Absence of hepatitis B surface antigenemia after vaccination.

Vaccination against hepatitis B is readily available and provides safe and effective immunization for individuals at increased risk for this disease. However, since the available vaccines employ a protein consisting of hepatitis B surface antigen, the question has arisen whether a detectable surface antigenemia might occur in recently vaccinated individuals. Employing two current immunoassays for hepatitis B surface antigen, we could not detect this marker in individuals either 1 hour or 24 hours after vaccination. We therefore conclude that the presence of surface antigen in the blood cannot be attributed to recent vaccination.

Performance optimization of left ventricular assistance. A computer model study.

Performance of temporary parallel left ventricular assistance was investigated and the theoretic conditions leading to optimal behavior of the mechanical system were explored. Computer models of nonpulsatile and pulsatile left ventricular assist devices (LVADs) were incorporated into a previously reported closed-loop simulation of the canine cardiovascular system. Assuming the assisted heart was capable of recovery, LVAD performance was assessed based on both myocardial oxygen balance and cardiac output. With a synchronous LVAD, and operating in a counterpulsation mode, these variables were sensitive to the phasing of pump ejection. Maximum reduction in cardiac oxygen consumption, maximum increase in oxygen availability, and maximum increase in cardiac output with the atrio-aortic device were obtained when pump ejection immediately followed aortic valve closure. These variables were directly proportional to the magnitude of bypass volume. The pulsatile asynchronous and nonpulsatile LVAD models affected oxygen balance in a similar manner, but neither performed so well as the synchronous model when equal bypass volumes were used. Ventricular uptake of blood provided a further 27% decrease in oxygen consumption and further 78% increase in oxygen availability than atrial uptake. In summary, the model predicted that the pulsatile synchronous LVAD, filling from the ventricle during heart systole and ejecting into either the ascending or descending aorta just after ventricular systole, would be most beneficial to both myocardial oxygen balance and cardiac output.

Evaluation of lamellar body number density as the initial assessment in a fetal lung maturity test cascade.

The objective of this study was to assess the sensitivity and specificity of lamellar body number density in the prenatal prediction of the respiratory distress syndrome. Seventy consecutive amniotic fluid specimens obtained by amniocentesis within 72 hours of delivery were assessed for lamellar body number density, optical absorbance at 650 nm, lecithin/sphingomyelin ratio and phosphatidylglycerol. A maturity criterion of > or = 46,000/microL for lamellar body number density yielded values for diagnostic sensitivity of 100% (7/7), specificity of 89% (49/55), positive predictive value of 54% (7/13) and negative predictive value of 100% (49/49). These values were also determined for the other analytes, with results similar to those reported elsewhere. Lamellar body number density is an effective and inexpensive first test for the rapid identification of the fetus at high risk for the respiratory distress syndrome. A cascade approach, using lamellar body number density as the first test and optical absorbance at 650 nm as the second test, improves the predictive value as compared to any single test of fetal lung maturity.

Variation of canine and feline frontal-plane QRS axes with lead choice and augmentation ratio.

The intraindividual variability in mean electric axis referable to choice of ECG leads and augmentation ratio was investigated by means of a digital computer program. Although, in theory, the choice of leads for determining the QRS axis should make no difference, the maximum intraindividual variation in axis angle was about 50 degrees for canine and feline subjects. The angle conputed for the lead combinations I and III and I and aVF will usually fall within 5 to 10 degrees of the mean of all lead combinations, but larger variations are seen at time. The application of an "augmentation ratio" for the augmented unipolar leads was most helpful when it was individually computed. Further methods of lead-vector improvement are discussed.

Lithium and symptomatic hyperparathyroidism.

Hyperparathyroidism with or without adenoma has occasionally been reported in association with lithium treatment, and in symptomatic patients depression, psychosis and an exacerbation of existing psychopathology may occur. Three lithium-treated patients with hyperparathyroidism are reported, in whom discontinuation of lithium in one and removal of parathyroid adenomata in two led to both a reduction in plasma calcium levels and an improvement in their psychopathology.

Contribution of cerebrospinal fluid to rheoencephalographic waveforms during hypoxic and +Gz stress.

Acceleration (G) forces generated by high performance aircraft induce a redistribution of blood and cerebrospinal fluid (CSF) in the head resulting in decreased visual function, and may lead to G-induced loss of consciousness (G-LOC). CSF provides a critical support function to the brain by equalizing the pressure changes occurring throughout the skull under G-stress, particularly to the venous system. While it has been acknowledged that understanding this role of the CSF system is essential in order to enhance G-tolerance, no such studies have been conducted since the 1940's, due to technical difficulties. We have shown that these can be surmounted through the development of rheoencephalography (REG), or impedance plethysmography of the head, to noninvasively monitor shifts in CSF under both hypoxic (oxygen deprivation in the laboratory) and actual +Gz stress (small centrifuge) conditions. Using surgical and physiologic techniques on New Zealand White rabbits, we have established the following: 1) REG contains information concerning the function of the vascular, CSF, and respiratory systems as they influence both beat-to-beat and bulk movement of cephalic fluids; 2) respiratory effects on cerebral blood volume and CSF pressure can be monitored with the REG; 3) REG waveforms obtained from rabbits under laboratory and +Gz stress conditions were similar to those obtained during human +Gz centrifuge exposures; 4) using (i) brief occlusions of blood flow into the head and (ii) withdrawals of CSF, it was estimated that the relative volumetric contributions of blood and CSF to the REG were 70% and 30%, respectively; and 5) physiologic responses to stress are reflected in changes in the frequency content of the REG.(ABSTRACT TRUNCATED AT 250 WORDS)

The physiologic changes of aging.

It is estimated that by the year 2030, 21.2% of the United States population will be 65 years of age or older. The elderly are the fastest growing segment of the population and use health care services extensively. Today 30% of all hospitalized individuals are elderly. The professional nurse must therefore be able to assess and assist elderly persons during the course of hospitalization. An important component of assessment is the ability to differentiate the normal physiologic changes of aging from the pathologic changes. To effectively intervene in a therapeutic plan of care the nursing professional must be aware of the limitations brought on by aging.