Zinc Deficiency and Long-Term Outcome in Cases After Isolated Intestinal Transplantation in Taiwan

OBJECTIVES

The small intestine is the primary site for absorption of dietary zinc. Intestinal transplant recipients are at high risk for zinc deficiency because of the long process of posttransplant adaptation. We initiated an intestinal transplant program in Taiwan in 2007. In this study, we aimed to retrospectively investigate the incidence of zinc deficiency in recipients after intestinal transplantation.

METHODS

Twenty-one isolated intestinal transplants were performed in 20 patients with 1 retransplantation. The level of serum zinc was monitored periodically, and zinc supplements were administered when zinc level was below 700 ng/mL. Twelve patients with graft above 1-year survival and with available related data were enrolled for the analysis of zinc deficiency. The levels of serum zinc were tracked, and the protocol of zinc supplementation is discussed herein.

RESULTS

The survival rates of 20 transplant recipients for 1 year, 3 years, and 5 years were 85%, 75%, and 65%, respectively. In the 12 grafts that survived longer than 1 year, we found that zinc deficiency was highest during the third (41.7%) to sixth (50%) month after transplantation. Sustained supplementation of zinc was required for over 70% of patients throughout the 3-year period to maintain their zinc level around the lower normal limit.

CONCLUSION

The outcome of isolated small bowel transplantation is promising. Periodical monitoring and sufficient dosing of zinc supplements should be considered into the posttransplant protocol to prevent zinc deficiency after intestinal transplantation.

Effect of fetal hemodynamics on growth in fetuses with single ventricle or transposition of the great arteries

OBJECTIVES

As birth weight is a critical predictor of outcome in neonates with congenital heart defect (CHD), the common problem of poor fetal growth in this population is clinically important. However, it is not well understood and the impact of fetal hemodynamics on fetal growth and birth weight in those with CHD has not been assessed. In this study, we sought to evaluate the association between combined cardiac output (CCO) and fetal middle cerebral artery (MCA) and umbilical artery (UA) pulsatility indices (PIs) and fetal growth in different subgroups of CHD, and to study the effects of fetal hemodynamics on late gestational weight gain. We hypothesized that fetuses with CHD will have lower CCO and be smaller at birth.

METHODS

This was a retrospective review of fetal echocardiograms from 67 fetuses diagnosed with hypoplastic left heart syndrome (HLHS, n = 30), non-HLHS single ventricle (SV) (n = 20) or dextrotransposition of the great arteries (d-TGA, n = 17), compared with normal controls (n = 42). CCO was calculated using valvar area, velocity-time integral and heart rate and indexed to estimated fetal weight. MCA- and UA-PI were calculated using systolic, diastolic and mean velocities. Fetal biometry was recorded. Regression models were used to study trends in CCO, MCA- and UA-PI and fetal biometry over gestational age. To evaluate fetal weight gain in late gestation, Z-scores of estimated fetal weight at 30 weeks and birth weight were compared. Regression analysis was used to determine the associations of CCO, indexed CCO and MCA- and UA-PI at 30 weeks with birth weight, length and head circumference Z-scores, in addition to weight gain late in gestation. The gestational age of 30 weeks was chosen based on previous studies that found evidence of poor weight gain in fetuses with CHD in late gestation, starting at around that time.

RESULTS

CCO increased with gestation in all four groups but the rate was slower in fetuses with HLHS and in those with SV. MCA-PI was lower in fetuses with HLHS compared with in those with non-HLHS-SV throughout gestation, suggesting different cerebral blood distribution. At the end of gestation, rate of fetal weight gain slowed in those with HLHS and in those with SV (similar to CCO curves), and head circumference growth rate slowed in all groups but controls. CCO, indexed CCO and MCA- and UA-PI did not correlate with any of the birth measurements or with weight gain late in gestation in fetuses with CHD.

CONCLUSIONS

We found no associations of CCO or MCA- and UA-PI with late gestational weight gain or biometry at birth in fetuses with CHD. This does not support fetal hemodynamics as the primary driver of suboptimal fetal growth in fetuses with SV. Future research could further explain genetic and placental abnormalities that may affect fetal growth in those with CHD. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Theoretical modeling and experimental demonstration of Raman probe induced spectral dip for realizing a superluminal laser

We have demonstrated experimentally a Diode-Pumped Alkali Laser (DPAL) with a Raman resonance induced dip in the center of the gain profile, in order to produce an anomalous dispersion, necessary for making the laser superluminal. Numerical calculations match closely with experimental results, and indicate that the laser is operating superluminally, with the group index far below unity (~0.00526) at the center of the dip. The estimated factor of enhancement in the sensitivity to cavity length perturbation is ~190, approximately equaling the inverse of the group index. This enhancement factor can be made much higher via optimal tuning of parameters. Such a laser has the potential to advance significantly the field of high-precision metrology, with applications such as vibrometry, accelerometry, and rotation sensing.

Analyzing Health-Related Quality of Life in the EVOLVE Trial: The Joint Impact of Treatment and Clinical Events

BACKGROUND

The Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events (EVOLVE) clinical trial evaluated the effects of cinacalcet on clinical events in patients with secondary hyperparathyroidism (sHPT) who were on hemodialysis. Health-related quality of life (HRQoL) was assessed by a generic, preference-based health outcome measure (EQ-5D) at scheduled visits and after a study event. Here, we report the HRQoL analysis from EVOLVE.

METHODS

We assessed changes in HRQoL from baseline to scheduled visits, and estimated the acute (3 mo) and chronic (beyond 3 mo) effects of sHPT-related events on HRQoL using generalized estimating equation analysis controlling for baseline HRQoL and randomized assignment.

RESULTS

Data on HRQoL were available for 3547 of 3883 subjects, with 1650 events in the placebo and 1502 in the cinacalcet arm. At the study end, no difference in change from baseline HRQoL was observed in the direct comparison of EQ-5D by treatment arms. The regression analysis showed significant effects of events on HRQoL and a modest positive effect of cinacalcet. Estimated quality-adjusted life-year gains were of similar magnitude based on the observed data or the predictions from the model, with only a small gain in precision from the predicted analysis.

CONCLUSIONS

By contrast with a conventional comparison, a regression analysis demonstrated large decrements in HRQoL after events and a modest improvement in HRQoL with cinacalcet. As randomized controlled trials are rarely powered to detect differences in HRQoL, a prespecified regression analysis may be acceptable to improve precision of the effects and understand their origin.

High-speed modulation in ladder transitions in Rb atoms using high-pressure buffer gas

Modulators using atomic systems are often limited in speed by the rate of spontaneous emission. One approach for overcoming this limit is to make use of a buffer gas such as Ethane, which causes rapid fine structure mixing of the P(1/2) and P(3/2) states, and broadens the absorption spectra of the D1 and D2 lines in alkali atoms. Employing this effect, we show that one can achieve high speed modulation using ladder transitions in Rubidium. We demonstrate a 100-fold increase, due to the addition of the buffer gas, in the modulation bandwidth using the 5S-5P-5D cascade system. The observed bandwidth of ~200 MHz is within a factor of 2.5 of the upper bound of ~0.51 GHz for the system used, and is limited by various practical constraints in our experiment. We also present numerical simulations for the system and predict that a much higher modulation speed should be achievable under suitable conditions. In combination with a tapered nano fiber or a SiN waveguide, it has the potential to be used for high-speed, low-power all-optical modulation.

Optically controlled waveplate at a telecom wavelength using a ladder transition in Rb atoms for all-optical switching and high speed Stokesmetric imaging

We demonstrate an optically controlled waveplate at ~1323 nm using the 5S(1/2)-5P(1/2)-6S(1/2) ladder transition in a Rb vapor cell. The lower leg of the transitions represents the control beam, while the upper leg represents the signal beam. We show that we can place the signal beam in any arbitrary polarization state with a suitable choice of polarization of the control beam. Specifically, we demonstrate a differential phase retardance of ~180 degrees between the two circularly polarized components of a linearly polarized signal beam. We also demonstrate that the system can act as a Quarter Wave plate. The optical activity responsible for the phase retardation process is explained in terms of selection rules involving the Zeeman sublevels. As such, the system can be used to realize a fast Stokesmetric imaging system with a speed of ~3 MHz. When implemented using a tapered nano fiber embedded in a vapor cell, this system can be used to realize an ultra-low power all-optical switch as well as a Quantum Zeno Effect based all-optical logic gate by combining it with an optically controlled polarizer, previously demonstrated by us. We present numerical simulations of the system using a comprehensive model which incorporates all the relevant Zeeman sub-levels in the system, using a novel algorithm recently developed by us for efficient computation of the evolution of an arbitrary large scale quantum system.

Optically controlled polarizer using a ladder transition for high speed Stokesmetric Imaging and Quantum Zeno Effect based optical logic

We demonstrate an optically controlled polarizer at ~1323 nm using a ladder transition in a Rb vapor cell. The lower leg of the 5S(1/2),F = 1->5P(1/2),F = 1,2->6S(1/2),F = 1,2 transitions is excited by a Ti:Sapphire laser locked to a saturated absorption signal, representing the control beam. A tunable fiber laser at ~1323 nm is used to excite the upper leg of the transitions, representing the signal beam. When the control beam is linearly polarized, it produces an excitation of the intermediate level with a particular orientation of the angular momentum. Under ideal conditions, this orientation is transparent to the signal beam if it has the same polarization as the control beam and is absorbed when it is polarized orthogonally. We also present numerical simulations of the system using a comprehensive model which incorporates all the relevant Zeeman sub-levels in the system, and identify means to improve the performance of the polarizer. A novel algorithm to compute the evolution of large scale quantum system enabled us to perform this computation, which may have been considered too cumbersome to carry out previously. We describe how such a polarizer may serve as a key component for high-speed Stokesmetric imaging. We also show how such a polarizer, combined with an optically controlled waveplate, recently demonstrated by us, can be used to realize a high speed optical logic gate by making use of the Quantum Zeno Effect. Finally, we describe how such a logic gate can be realized at an ultra-low power level using a tapered nanofiber embedded in a vapor cell.

Cost per responder analysis in patients with secondary hyperparathyroidism on dialysis treated with cinacalcet

BACKGROUND

Growing financial pressure on US dialysis providers requires economic efficiency considerations. The objective of this study was to examine short-term economic efficiencies of a cinacalcet-based treatment approach for secondary hyperparathyroidism.

METHODS

This study retrospectively assessed cost per biochemical response of the OPTIMA trial. OPTIMA was conducted in end-stage renal disease patients to compare biochemical control in patients receiving cinacalcet in addition to vitamin D sterols and phosphate binders vs patients receiving vitamin D sterol and phosphate binders alone. It explored three laboratory measurement response definitions from baseline to week 23: (1) decreases in parathyroid hormone (PTH) ≥30%; (2) PTH ≤ 300 pg/ml; and (3) PTH ≤ 300 pg/mL, calcium <9.5 mg/dL and phosphorus <5.5 mg/dL. Medication use and costs were measured to calculate average costs and incremental cost per responder. Stratification by lower and higher baseline PTH assessed cost per response by disease severity.

RESULTS

There were 38-77% more responders with cinacalcet vs control, depending on response definition. Mean (SD) per patient total medication costs were $5423 ($3698) for cinacalcet and $2633 ($2334) for control, leading to a mean difference of $2790 over 23 weeks. When response was defined as a decrease in PTH ≥ 30% from baseline, the average cost per responder was $11,266 for control vs $7027 for cinacalcet. The incremental cost per incremental responder ranged from $5186-$9168. Across all response measures, cost per responder was lower in patients with lower baseline PTH.

CONCLUSIONS

Representing a more efficient allocation of economic resources over the short-term, cinacalcet-based treatment algorithm led to a lower cost per biochemical response, particularly in patients with lower disease severity, vs vitamin D sterols and phosphate binders alone. These findings should be interpreted alongside the study limitation of converting international trial-based medication utilization into US costs.

High efficiency optical modulation at a telecom wavelength using the quantum Zeno effect in a ladder transition in Rb atoms

We demonstrate a high-efficiency optical modulator at ~1323 nm using the quantum Zeno effect in a ladder transition in a Rb vapor cell. The lower leg of the transitions represents the control beam while the upper leg of the transitions represents the signal beam. The cross-modulation of the signal beam transmission is observed as the control beam is intensity modulated, and is explained in terms of the quantum Zeno effect. We observe a modulation depth of near 100% at frequencies up to 1 MHz and demonstrate modulation at speeds up to 75 MHz, with a 3 dB bandwidth of about 5 MHz, limited by the homogeneous linewidth of the intermediate state. We also describe how much higher modulation speeds could be realized by using a buffer gas to broaden the transitions. We identify and explain the special conditions needed for optimizing the modulation efficiency. Numerical simulations of modulation at ~1 GHz are presented. The maximum modulation speed is found to scale with the pressure-broadened linewidth of the intermediate state, so that much higher speeds should be attainable.

Fast-light in a photorefractive crystal for gravitational wave detection

We demonstrate superluminal light propagation using two frequency multiplexed pump beams to produce a gain doublet in a photorefractive crystal of Ce:BaTiO(3). The two gain lines are obtained by two-wave mixing between a probe field and two individual pump fields. The angular frequencies of the pumps are symmetrically tuned from the frequency of the probe. The frequency difference between the pumps corresponds to the separation of the two gain lines; as it increases, the crystal gradually converts from normal dispersion without detuning to an anomalously dispersive medium. The time advance is measured as 0.28 sec for a pulse propagating through a medium with a 2 Hz gain separation, compared to the same pulse propagating through empty space. We also demonstrate directly anomalous dispersion profile using a modified experimental configuration. Finally, we discuss how anomalous dispersion produced this way in a faster photorefractive crystal (such as SPS: Sn(2)P(2)S(6)) could be employed to enhance the sensitivity-bandwidth product of a LIGO type gravitational wave detector augmented by a White Light Cavity.

ETS transcription factor ER81 is required for the pacinian corpuscle development

ER81, a member of the ETS family of transcription factors, is involved in processes of specification of neuronal identity, control of sensory-motor connectivity, and differentiation of muscle spindles. Spindles either degenerate or are abnormal in mutant mice lacking ER81. We examined whether ER81 is required for the development of another class of mechanoreceptors, the Pacinian corpuscle. ER81 was expressed by the inner core cells of the corpuscles, as reflected by expression of the lacZ reporter gene in Er81(+/lacZ) mutants, thereby suggesting a role for ER81 in the corpuscle development. No Pacinian corpuscles or their afferent nerve fibers were present in the crus of Er81 null mice at birth. Legs of mutant embryos examined at E16.5 were also devoid of the corpuscles, but not of their afferents. Thus, Pacinian corpuscles do not form, and their afferents do not survive, in the absence of ER81. A deficiency of dorsal root ganglia neurons expressing calretinin, a marker for neurons subserving Pacinian corpuscles, correlated with the absence of corpuscles and their afferents in Er81 null mice. These observations indicate a requirement for ER81 in the assembly of Pacinian corpuscles and the survival of the sensory neurons that innervate them.

Electrical interaction between two cylinders with an ion-penetrable charged membrane in an oil/water interface

The electrical interaction between two long, parallel cylinders each is covered by an ion-penetrable charged membrane immersed in an oil/water interface is investigated. The effects of contact angle, radius of cylinder, and membrane thickness on the electrical interaction force are examined. The results of numerical simulation reveal that the following conditions lead to a greater electrical interaction force: (i) a larger contact angle, i.e. a larger fraction of a cylinder in the oil phase; (ii) a larger cylinder radius; and (iii) a thinner membrane. For a fixed ionic strength, the electrical interaction force is insensible to the type of electrolytes in the water phase, in general. However, if two cylinders are close enough, then the higher the valence of counterions the greater the electrical interaction force.

Electrophoretic mobility of a particle covered with an ion-penetrable membrane

The electrophoretic behavior of a planar particle covered by an ion-penetrable membrane, which simulates a biological entity, is investigated. We show that, in general, a point charge model will overestimate the electrophoretic mobility of a particle and the deviation increases with the increase in the concentration of fixed charge and with the decrease in the thickness of membrane layer. As in the case of a point charge model, the present model also predicts a local maximum in the absolute mobility as the thickness of membrane layer varies. If the sizes of counterions of various valences are the same, then the lower the valence of counterions, the larger the mobility, and the larger the counterions, the greater the mobility. The latter is consistent with the experimental observations in the literature. For the level of the concentration of fixed charge examined, the effect of coions on the mobility is negligible.

Electrokinetic flow in a planar slit covered by an ion-penetrable charged membrane

The electrokinetic flow of an electrolyte solution in a planar slit covered by an ion-penetrable charged membrane layer is analyzed theoretically. An approximate analytical expression for the spatial variation in the electrical potential is derived, and the electroosmotic velocity, the total electric current, and the streaming potential of the system under consideration are evaluated. The effects of epsilon' (relative permittivity of liquid phase/relative permittivity of membrane layer), eta' (viscosity of liquid phase/viscosity of membrane layer) and the valence of anions (coions) on the volumetric flow rate and total current are examined. We show that the effect of the valence of cations (counterions) on the volumetric flow rate is less significant than that of epsilon' and that of eta'. However, the effect of epsilon' on the total current is less significant than that of the valence of cations and that of eta'. The variation of total current as a function of ionic strength is found to have a local minimum, regardless of whether a pressure gradient is applied or not. The absolute streaming potential has a local maximum as the concentration of fixed charge varies, which was not found in previous studies.

Control of TH2 polarization by the chemokine monocyte chemoattractant protein-1

Activated T lymphocytes differentiate into effector cells tailored to meet disparate challenges to host integrity. For example, type 1 and type 2 helper (T(H)1 and T(H)2) cells secrete cytokines that enhance cell-mediated and humoral immunity, respectively. The chemokine monocyte chemoattractant protein-1 (MCP-1) can stimulate interleukin-4 production and its overexpression is associated with defects in cell-mediated immunity, indicating that it might be involved in T(H)2 polarization. Here we show that MCP-1-deficient mice are unable to mount T(H)2 responses. Lymph node cells from immunized MCP-1(-/-) mice synthesize extremely low levels of interleukin-4, interleukin-5 and interleukin-10, but normal amounts of interferon-gamma and interleukin-2. Consequently, these mice do not accomplish the immunoglobulin subclass switch that is characteristic of T(H)2 responses and are resistant to Leishmania major. These effects are direct rather than due to abnormal cell migration, because the trafficking of naive T cells is undisturbed in MCP-1(-/-) mice despite the presence of MCP-1-expressing cells in secondary lymphoid organs of wild-type mice. Thus, MCP-1 influences both innate immunity, through effects on monocytes, and adaptive immunity, through control of T helper cell polarization.

MCP-1 deficiency reduces susceptibility to atherosclerosis in mice that overexpress human apolipoprotein B

The earliest recognizable atherosclerotic lesions are fatty streaks composed of lipid-laden macrophages (foam cells). Circulating monocytes are the precursors of these foam cells, but the molecular mechanisms that govern macrophage trafficking through the vessel wall are poorly understood. Monocyte chemoattractant protein-1 (MCP-1), a member of the chemokine (chemotactic cytokine) family, is a potent monocyte agonist that is upregulated by oxidized lipids. Recent studies in hypercholesterolemic mice lacking apo E or the low-density lipoprotein receptor have suggested a role for MCP-1 in monocyte recruitment to early atherosclerotic lesions. To determine if MCP-1 is critically involved in atherogenesis in the setting of elevated physiological plasma cholesterol levels, we deleted the MCP-1 gene in transgenic mice expressing human apo B. Here we report that the absence of MCP-1 provides dramatic protection from macrophage recruitment and atherosclerotic lesion formation in apo B transgenic mice, without altering lipoprotein metabolism. Taken together with the results of earlier studies, these data provide compelling evidence that MCP-1 plays a critical role in the initiation of atherosclerosis.

Dynamic Interactions of Two Electrical Double Layers

The unsteady-state electrical potential and the concentrations of ions between two identical, negatively-charged particles immersed in an a:b electrolyte solution are investigated. In particular, the effects of ionic strength, I, the geometric mean of the diffusivities of counterions Dcon and coions Dco, D, the separation distance between two particles, H, and the surface charge density, sigma0, on these distributions are examined. We conclude that under the following conditions a system needs a longer time for ions to reach equilibrium distributions: (a) small I, (b) small D, (c) large H, and (d) large sigma0. The rate of approach of two particles is faster if both surfaces are maintained at constant potential than if both surfaces are at constant charge density. The dynamic behavior of the relaxation of ions in the double layers has the effect of retarding the motion of particles. The deviation in the contact time between two particles predicted by an equilibrium model, which assumes that the distributions of ions in a double layer reach the Boltzmann distribution instantly, from that estimated by the corresponding dynamic model is on the order of 10%. Copyright 1997 Academic Press. Copyright 1997Academic Press

F-actin disruption attenuates agonist-induced [Ca2+], myosin phosphorylation, and force in smooth muscle

Cytochalasins B and D (at 10 microM) inhibited stress development induced by 1 microM carbachol in bovine tracheal smooth muscle by 55% and 90%, respectively. Glucose depletion was ineffective in inhibiting carbachol-induced contraction, indicating that inhibition of glucose transport was not the cause. Cytochalasin D-treated smooth muscle cells appeared collapsed, with spiky protrusions from the cell membrane. Deconvolution of fluorescent images of fluorescein isothiocyanate-phalloidin-labeled smooth muscle cells revealed concentrations of actin filaments near the cell periphery, including near the spiky protrusions. Cytochalasin B attenuated carbachol-induced intracellular Ca2+ concentration ([Ca2+]), especially the initial peak intracellular [Ca2+]. Cytochalasin B also attenuated carbachol-induced myosin light chain phosphorylation. However, when the myosin phosphorylation data were plotted against time-matched intracellular [Ca2+] data, the two relationships in control and cytochalasin B-treated smooth muscle were similar, suggesting that the changes in myosin phosphorylation could be explained by the changes in intracellular [Ca2+]. These results suggest that actin filaments in smooth muscle cells are dynamic and may be an integral component of Ca2+ regulation and/or signal transduction in receptor-coupled mechanisms.

Reaction of ozone with protein tryptophans: band III, serum albumin, and cytochrome C

Treatment of red cell ghosts with ozone inhibited both AChE (marking the outside of the membrane) and G3PDH (marking the inside of the membrane). There was no change in tryptophan fluorescence of the ghosts after the ozone treatment. Band 3 protein was isolated from the ozone-treated ghosts. The protein was digested with trypsin to obtain water soluble peptides from the cytoplasmic N-terminal tail and the interhelical loops. Fluorescent peptides included GWVIHPLGLR from the outer loop between helices 7 and 8, and peptide WMEAAR from the N-terminal cytoplasmic tail. Neither one of these peptides was oxidized by ozone. This was true whether or not the ghosts were sealed. We conclude that the position of these tryptophans either in the membrane structure, or because of binding to other proteins in the cytoplasmic tail, protects them from oxidation by ozone. Treatment of horse heart cytochrome c with ozone did not change the absorbance spectrum in the heme region or the tryptophan absorbing region. HPLC of the ozone-treated cytochrome c showed that cytochrome c was being modified, indicated by a change in the elution time. Treatment of cytochrome c with ozone did not change the activity in the NADH-cytochrome c reductase assay. Digestion of the ozone-treated cytochrome c with trypsin gave peptides which demonstrated normal fluorescence. (Cytochrome c has abnormally low fluorescence, which is not changed by ozone exposure.) The peptides were separated by HPLC. The fluorescence of the tryptophan-containing peptide (GITWK) was not decreased by treatment of the cytochrome c by ozone. Amino acid analysis of the ozone-treated cytochrome c indicated that methionine was oxidized. We conclude that tryptophan in cytochrome c is protected from oxidation by ozone because of the interaction with the porphyrin ring. Bovine serum albumin and human serum albumin were treated with ozone. There was a monotonic decrease in tryptophan fluorescence in both cases. Digestion of BSA with trypsin produced two fluorescent peptides. The peptide FWGK was identified by coelution with the authentic peptide. The putative peptide AWSVAR was not the same as the chemically synthesized peptide. The peptide sequences FWGK and "AWSVAR" were both oxidized in ozone-treated bovine serum albumin, with no detectable discrimination. Tryptic digestion of the ozone-treated human serum albumin produced a single fluorescent peptide, which was oxidized by ozone. The putative peptide AWAVAR in the tryptic digest of HSA was distinct from chemically synthesized peptide. The oxidation of tryptophans in proteins by ozone is markedly influenced by position in tertiary structure, position in membrane structure, and by chemical interactions within the protein.

Rediscovering thalidomide: a review of its mechanism of action, side effects, and potential uses

Thalidomide, a hypnosedative drug introduced in the 1950s, has been used in a variety of dermatologic conditions during the past few decades. Although originally withdrawn from the world market on discovery of its teratogenic effect, it has since been selectively reintroduced for use in various disorders thought to have an autoimmune or inflammatory basis. A review of the literature focused on clinical uses of thalidomide in the treatment of dermatologic diseases was performed. Diseases for which thalidomide has been found effective include erythema nodosum leprosum, prurigo nodularis, actinic prurigo, discoid lupus erythematosus, aphthous stomatitis, Behçet's syndrome, and graft-versus-host disease. Side effects such as teratogenicity and peripheral neuropathy remain its limiting factor. Thalidomide is a useful addition to the therapeutic armamentarium for treatment-resistant dermatoses as long as proper vigilance for adverse effects is maintained.

Electrophoretic mobility of biological cells in asymmetric electrolyte solutions

The electrophoretic mobility of a particle covered by a membrane in an a:b electrolyte solution is modeled theoretically. The membrane, which simulates the surface of a biological cell, is ion-penetrable, and carries homogeneously distributed negative fixed charges. An approximate expression for the electrophoretic mobility is derived. Based on the results of numerical simulation, we conclude the following: (1) The absolute Donnan potential increases with the concentration of the fixed charges C0, but decreases with the ionic strength I. (2) The greater the valence of cation alpha, the lower the absolute potential distribution. (3) The greater the C0, the greater the absolute mobility of a particle, magnitude of mu, and the greater the friction coefficient of the membrane phase gamma, the smaller the magnitude of mu. (4) A large I or a large a leads to a small magnitude of mu. (5) The greater the ratio (permittivity of solution/permittivity of membrane phase), the smaller the magnitude of mu. (6) For a large gamma, magnitude of mu decreases with the thickness of membrane d under the condition of constant amount of fixed charges. However, if gamma is sufficiently small, the variation of magnitude of mu as a function of d exhibits a maximum. The classic result of Smoluchowski for the electrophoretic mobility of a rigid particle can be recovered as a limiting case of the present model.

Effect of butter, mono- and polyunsaturated fatty acid-enriched butter, trans fatty acid margarine, and zero trans fatty acid margarine on serum lipids and lipoproteins in healthy men

The effect of diets containing 50% of fat calories from butter, butter enriched with mono- and polyunsaturated fatty acids, and margarines with and without trans fatty acids on the serum lipids of 38 healthy men in a free-living condition have been determined. Serum lipid responses to the high level of individual dietary fats were unexpectedly small. The butter diet produced a small, but significant rise (5%) in the total serum cholesterol and low density lipoprotein (LDL)-cholesterol, relative to all other diets. Enrichment of butter with either olive oil (50/50) or sunflower oil (50/50) failed to reduce serum lipid levels below habitual diet values. Hard margarine, containing 29% trans fatty acids, caused a decrease in apolipoprotein A-I and B levels, but did not change total serum cholesterol or LDL-cholesterol levels, relative to habitual diet values. A soft margarine, high in linoleate, with no trans fatty acids reduced total cholesterol, LDL-cholesterol, and apolipoprotein B significantly, relative to all diets. Soft margarine high density lipoprotein (HDL)-cholesterol levels remained unchanged, but apolipoprotein A-I values were decreased relative to habitual and butter diets. The quantities of saturated fatty acids and the sum of monounsaturated and polyunsaturated fatty acids consumed on the hard and soft margarines were equal; therefore, the different response of serum cholesterol and LDL-cholesterol between these two diets is attributable to the trans fatty acids in the hard margarine. The data indicate that trans fatty acids are not metabolically equivalent to the natural cis isomers and that they affect the serum lipid profile adversely.

Implementing a strategic recruitment and retention plan

Nurse administrators were faced with how to staff for a rapid expansion in number of beds in the face of a 15% nurse vacancy rate. The authors discuss how they addressed this issue through their multifaceted strategic plan.

Modeling the repair of radiation-induced DNA double-strand breaks

A problem often overlooked in the study of the repair of radiation-induced DNA double-strand breads (DSBs) is the question of what the status of a regular site is in the DNA duplex immediately after a radiation treatment. Here, we suggest a mixed repair mechanism which consists of a gradual process and an instantaneous process. A comparison of the present kinetic model with those which have appeared in the literature shows that the former is a generalization of the latter. We have shown that different repair mechanisms may lead to equivalent mathematical representations. Therefore, care must be taken in interpreting the repair mechanism on the basis of the experimentally observed transient number of DSBs.

A kinetic analysis of the repair of radiation-induced DNA double-strand breaks

The repair of radiation-induced DNA double-strand breaks (DSBs) is analyzed kinetically. It is assumed that a fraction of the damaged sites in the DNA duplex are irreparable. The kinetic model takes the effect of radiation dose into account. The analysis of the available experimental data reveals that, although the number of irreparable DSBs is a quadratic function of radiation dose, the normalized number of irreparable DSBs correlates linearly with this variable.

A stochastic analysis of the repair of radiation-induced DNA double-strand breaks

A three-state stochastic model is described for the repair of radiation-induced double-strand breaks (DSBs) in DNA. If irradiated, a site or region in DNA is assumed to be in a potentially damaged state; this site may either become permanently damaged or be repaired after a certain period of time. The result of the analysis of the available experimental data reveals that the present two-parameter model is capable of interpreting the rapid decrease in the number of DSBs in the initial period, which cannot be predicted by previously proposed models. The stochastic analysis yields not only the temporal variation of the mean of the number of DSBs but also its variance, and therefore is a generalization of the conventional deterministic models.

A stochastic simulation of tumor growth

The growth of a tumor is described by a nonlinear stochastic representation. A systematic approach based on Taylor series expansion is adopted to solve the nonlinear master equation governing the variation of tumor weight as a function of time. The analysis of the available experimental data reveals that the growth rate of a tumor has a power law dependence on its weight.

Marketing: handle with care

Because hospitals offer the public a unique product--health care--they must be extremely careful how they market their services. The authors discuss current attitudes toward health care marketing and the ethical considerations that must temper the marketing strategies of voluntary, not-for-profit hospitals.

Managing strategic change: moving others from awareness to action

A recent study of 10 hospitals investigated how institutions actually manage change, and how their decisions and actions mesh with accepted formal planning and management processes. In every instance, strategic change was managed in different ways, reflecting variations in organizational capabilities, culture, values and traditions. However, there are underlying unities within the diversities of change. This article focuses on the change management process: how 10 hospitals moved from an awareness of the need to do something different to the actions taken to implement change. The theoretical underpinnings of the change management process will be reviewed in light of what actually happened at the study hospitals.

Antigenic activity of human urothelial tissue

Partially purified extracts from 71 human urothelial tumors and from 75 human urothelial non-tumor tissues were used as competing antigens in competition radioimmunoassay in an effort to detect the presence of 1 of the structural components of type C-ribonucleic and viruses, the p30 core protein. Testing of the tissue extracts was carried out by homologous and heterologous assay systems using 125I-labeled murine (Friend) and feline (Rickard) p30 antigens and anti-feline and anti-murine p30 antisera. The homologous assays were designed to detect the presence of p30 antigens in the human tissue extracts having similar characteristics to the p30 antigens of either the feline or murine type C viruses. The heterologous assay system was designed to detect interspecies antigenic determinants common to murine and feline viruses and also primate viruses. A competing antigen present in 28 per cent of the tissue extracts assayed demonstrated an antigenic protein that competed with the viral p30 protein used in the heterologous radioimmunoassay system and to a lesser extent in the homologous feline radioimmunoassay system. Antigenic competitor proteins were found in tumor and non-tumor tissue. These data suggest that some human urothelial tissues contain at least part of the genome of 1 or more type C viruses. Those tissues that are positive only in the heterologous assay system behave like viral p30 antigens already identified in tissues of several other primates. Those tissues that are positive in the heterologous assay system and the homologous system indicate that the p30 antigenic activity is closely related to that p30 present in feline C-type viruses. Further purification and more detailed characterization of those competing proteins are now under study.