Reduced focal fiber collinearity in the cingulum bundle in adults with obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a disabling condition, often associated with a chronic course. Given its role in attentional control, decision-making, and emotional regulation, the anterior cingulate cortex is considered to have a key role in the pathophysiology of the disorder. Notably, the cingulum bundle, being the major white matter tract connecting to this region, has been historically a target for the surgical treatment of intractable OCD. In this study, we aimed to identify the extent to which focal-more than diffuse-abnormalities in fiber collinearity of the cingulum bundle could distinguish 48 adults with OCD (mean age [SD] = 23.3 [4.5] years; F/M = 30/18) from 45 age- and sex-matched healthy control adults (CONT; mean age [SD] = 23.2 [3.8] years; F/M = 28/17) and further examine if these abnormalities correlated with symptom severity. Use of tract-profiles rather than a conventional diffusion imaging approach allowed us to characterize white matter microstructural properties along (100 segments), as opposed to averaging these measures across, the entire tract. To account for these 100 different segments of the cingulum bundle, a repeated measures analysis of variance revealed a main effect of group (OCD < CONT; F_[1,87] = 5.3; P = 0.024) upon fractional anisotropy (FA, a measure of fiber collinearity and/or white matter integrity), in the cingulum bundle, bilaterally. Further analyses revealed that these abnormalities were focal (middle portion) within the left and right cingulum bundle, although did not correlate with symptom severity in OCD. Findings indicate that focal abnormalities in connectivity between the anterior cingulate cortex and other prefrontal cortical regions may represent neural mechanisms of OCD.

The simultaneous role of an alveolus as flow mixer and flow feeder for the deposition of inhaled submicron particles

In an effort to understand the fate of inhaled submicron particles in the small sacs, or alveoli, comprising the gas-exchange region of the lung, we calculated the flow in three-dimensional (3D) rhythmically expanding models of alveolated ducts. Since convection toward the alveolar walls is a precursor to particle deposition, it was the goal of this paper to investigate the streamline maps' dependence upon alveoli location along the acinar tree. On the alveolar midplane, the recirculating flow pattern exhibited closed streamlines with a stagnation saddle point. Off the midplane we found no closed streamlines but nested, funnel-like, spiral, structures (reminiscent of Russian nesting dolls) that were directed towards the expanding walls in inspiration, and away from the contracting walls in expiration. These nested, funnel-like, structures were surrounded by air that flowed into the cavity from the central channel over inspiration and flowed from the cavity to the central channel over expiration. We also found that fluid particle tracks exhibited similar nested funnel-like spiral structures. We conclude that these unique alveolar flow structures may be of importance in enhancing deposition. In addition, due to inertia, the nested, funnel-like, structures change shape and position slightly during a breathing cycle, resulting in flow mixing. Also, each inspiration feeds a fresh supply of particle-laden air from the central channel to the region surrounding the mixing region. Thus, this combination of flow mixer and flow feeder makes each individual alveolus an effective mixing unit, which is likely to play an important role in determining the overall efficiency of convective mixing in the acinus.

Temperature-Sensitive Resistance to Wheat streak mosaic virus in CO960333 and KS06HW79 Wheat

Temperature-sensitive resistance (TSR) that can protect against losses to Wheat streak mosaic virus (WSMV) has been described in elite wheat germplasm. A TSR identified in the advanced breeding line CO960333 and its derivative KS06HW79 was examined in growth-chamber tests conducted under constant temperature regimes of 18, 21, and 24°C against an array of WSMV isolates. At 18°C, all tested isolates systemically infected the pedigree parents, while the progeny line CO960333 remained free of symptoms; at 24°C, all lines were susceptible. At the intermediate temperature of 21°C, the TSR of KS06HW79 was effective in contrast to the TSRs of KS03HW12 and 'RonL'. In field trials conducted in 2011 and 2012, the TSR expressed in KS06HW79 conferred complete protection against yield losses from inoculation with the Sidney 81 isolate of WSMV, while the TSR of RonL conferred similar protection in 2012 but allowed small losses in 2011. The resistance expressed by KS06HW79 is likely not due to the Wsm1 gene because it did not contain the tightly linked J15 sequence-characterized amplified region (SCAR) DNA marker. These findings suggest that KS06HW79 could be an additional TSR source of value to wheat-breeding programs seeking to control losses from WSMV.

Low-Reynolds-number swimmer utilizing surface traveling waves: analytical and experimental study

Microscale slender swimmers are frequently encountered in nature and are now used in microrobotic applications. The swimming mechanism examined in this paper is based on small transverse axisymmetric traveling wave deformations of a cylindrical long shell. The thin-shelled device is assumed to be inextensible at the middle surface and extensible at the surface wetted by the fluid. Assuming low-Reynolds-number hydrodynamics, an analytical solution is derived for waves of small amplitudes compared with the cylinder diameter. We show that swimming velocity increases with β(1) (the ratio of cylinder radius to wavelength) and that swimming velocity is linearly dependent on wave propagation velocity, increasing to leading order with the square of the ratio of wave amplitude to wavelength β(2) and decreasing with the wall thickness. A fourth-order correction in β(2) was also calculated and was found to have a negative effect on the swimming velocity. The results for a shell of negligible-wall thickness were compared with Taylor's solution for an inextensible two-dimensional flat membrane undergoing a waving motion and Felderhof's results [Phys. Fluids 22, 113604 (2010)] for an unbounded flow field and negligible-wall thickness. We show that Taylor's analytic solution is a particular limiting case of the present solution, assuming zero wall thickness and infinite values of β(1). The present mechanism was also compared with Taylor's well known solutions of waving planar and helical circular tails. We show that the present approach yields higher velocities as β(1) increases, whereas, the opposite occurs for waving tails. Indeed, in the region where β(1)>15, the present approach yields velocities nearly as fast as Taylor's helical waving tail while consuming less power and with a design that is considerably more compact. In this regime, the axisymmetric swimmer is twice as fast as Taylor's planar-tail swimmer for an additional investment of only one-third of the power. Experiments were conducted using a macroscale autonomous model immersed in highly viscous silicone fluid. We outlined how the proposed mechanism was realized to propel an elongated, yet finite, swimmer. Measured data demonstrate the effects of wave velocity and wavelength on swimming speed, showing good agreement with analytical results.

Isolation and characterization of virus-specific double-stranded DNA from tissues infected by bean golden mosaic virus

A double-stranded (ds) DNA which may be a replication intermediate was isolated from bean (Phaseolus vulgaris L. "Top Crop") leaves systemically infected with bean golden mosaic virus, a whitefly-transmitted plant virus with a genome of circular single-stranded (ss) DNA. The isolation method used phenol/chloroform extraction, hydroxyapatite column chromatography, and rate-zonal centrifugation. The dsDNA had sequences complementary to those of viral DNA. The guanine-plus-cytosine content was 35%, and the sedimentation coefficient in alkaline sucrose density gradients was similar to that of viral ssDNA. Digestion of the dsDNA by Hha I endonuclease produced fragments that corresponded exactly in number and size with those produced by complete digestion of circular viral ssDNA by Hha I, when the fragments were denatured and analyzed on polyacrylamide gels. The dsDNA molecule was a circular structure with one discontinuity in one strand; hybridization results suggest that some of a the dsDNA has a discontinuity in the viral strand and some has a discontinuity in the nonviral strand. On the basis of these structures for the dsDNA, a preliminary model for replication of viral DNA is discussed.

Identification of Variants of the High Plains virus Infecting Wheat in Kansas

The properties of two virus isolates (U04-82 and U04-83) obtained from two wheat (Triticum aestivum) plants expressing mosaic symptoms were investigated using enzyme-linked immunosorbent assay (ELISA), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), time-of-flight mass spectrometry (TOFMS), and infection of wheat with resistance to Wheat streak mosaic virus (WSMV). The coat protein mass was estimated by SDS-PAGE as approximately 32 kDa for U04-82 and 30 kDa for U04-83. The amino acid sequence of the coat protein of U04-82 was 99.6 and 85.5% identical to two isolates, ABC58222 and TX96, respectively, of High Plains virus (HPV) described from Texas. U04-82 was transmitted by wheat curl mites and caused significant yield reductions in wheat resistant to WSMV. U04-83 was actually two distinct virus isolates whose capsid protein amino acid sequences were only 57 and 50% similar to that of TX96. Antiserum prepared to a synthetic peptide from the sequence of the U04-83 isolate recognized the two U04-83 isolates, but not the U04-82 isolate.

Temperature-Sensitive Wheat streak mosaic virus Resistance Identified in KS03HW12 Wheat

Wheat streak mosaic virus (WSMV) infection reduces seed yield and quality in wheat. These losses can be alleviated significantly by exploiting genetic host plant resistance. A new source of temperature-sensitive resistance to WSMV, KS03HW12, and its parental lines (KS97HW29/ KS97HW131//KS96HW100-5) were evaluated in both greenhouse and field conditions. Parental wheat lines were exposed to WSMV pressure under different temperatures in growth chambers to determine the stability of the resistance, and 2 years of field yield trials were conducted to confirm effectiveness. To determine the effectiveness of its resistance against a spectrum of isolates, KS03HW12 was tested against six different WSMV isolates of different geographic origins. Among the three pedigree parents, only one, KS97HW29, was resistant. The parental lines of KS97HW29 are not available for testing; therefore, the presumed origin of the resistance could not be further confirmed. None of the six tested WSMV isolates systemically infected KS03HW12 at 18°C. Yield of KS03HW12 in field tests was not different from healthy controls. Thus, the elite winter wheat KS03HW12 appears to be a stable and effective source of temperature-sensitive resistance to WSMV and should be useful for wheat breeding programs.

Dissipative particle dynamics simulation of flow generated by two rotating concentric cylinders: boundary conditions

The dissipative particle dynamics (DPD) method was used to simulate the flow in a system comprised of a fluid occupying the space between two cylinders rotating with equal angular velocities. The fluid, initially at rest, ultimately reaches a steady, linear velocity distribution (a rigid-body rotation). Since the induced flow field is solely associated with the no-slip boundary condition at the walls, we employed this system as a benchmark to examine the effect of bounce-back reflections, specular reflections, and Pivkin-Karniadakis no-slip boundary conditions, upon the steady-state velocity, density, and temperature distributions. An additional advantage of the foregoing system is that the fluid occupies inherently a finite bounded domain so that the results are affected by the prescribed no-slip boundary conditions only. Past benchmark systems such as Couette flow between two infinite parallel plates or Poiseuille flow in an infinitely long cylinder must employ artificial periodic boundary conditions at arbitrary upstream and downstream locations, a possible source of spurious effects. In addition, the effect of the foregoing boundary conditions on the time evolution of the simulated velocity profile was compared with that of the known, time-dependent analytical solution. It was shown that bounce-back reflection yields the best results for the velocity distributions with small fluctuations in density and temperature at the inner fluid domain and larger deviations near the walls. For the unsteady solutions a good fit is obtained if the DPD friction coefficient is proportional to the kinematic viscosity. Based on dimensional analysis and the numerical results a universal correlation is suggested between the friction coefficient and the kinematic viscosity.

Temperature Sensitivity and Efficacy of Wheat streak mosaic virus Resistance Derived from CO960293 Wheat

Wheat yields often are limited by infection by Wheat streak mosaic virus (WSMV). Host plant resistance to WSMV can reduce losses. This study was conducted to characterize a new source of temperature-sensitive resistance found in CO960293 wheat. The source of the temperature-sensitive resistance in CO960293 is unknown. Parental and other wheat lines were tested for WSMV resistance using 51 WSMV isolates under different temperatures to determine the stability of the resistance, and yield trials were conducted in the field for 3 years. All parental wheat lines became infected by WSMV at all temperatures and were infective in back assay to 'Tomahawk' wheat. No WSMV isolate defeated the resistance of CO960293 at 18°C. Yield of CO960293 in field trials was reduced in only 1 of 3 years. Our data demonstrate that this wheat line can be a valuable source of resistance to WSMV in wheat programs, particularly in areas where temperatures are cool following planting in the fall.

Une étude exploratoire des pratiques et des comportements radiologiques devant la découverte d’une anomalie « probablement bénigne » sur la mammographie : à propos de 176 radiologues

OBJECTIVES

To evaluate mid-term management of patients with category 3 findings (probably benign, ACR BI-RADS) at mammography three months after a CME course on breast cancer.

METHODS

A questionnaire (33 items) was sent to 529 radiologists, three months after the CME course (May-December 2002). The answers were analysed using the chi-square test.

RESULTS

A total of 176 radiologists completed the questionnaire; 63 were part of an organized screening mammography program; 162 used the BI-RADS classification. In the presence of a class 3 finding, 158 radiologists recommended short term follow-up, 28 recommended biopsy, 9 upgraded the level of abnormality, 116 consulted another radiologist, 42 consulted an expert mammographer, 36 submitted the case to a multidisciplinary committee and 12 asked for an overread. Management with short term interval follow-up was worrisome to 91 radiologists for fear of unfavorable outcome, and to 47 radiologists because of possible litigation. Twenty-six radiologists had difficulty explaining to patients the need for short term follow-up. The median score for perceived stress by the radiologists was 3 (0=low and 10=high).

CONCLUSION

The practices of this sample of French radiologists are consistent with the recommendations presented during the CME course and by the ANAES. They may have some difficulty in communicating with patients the need for follow-up. The ethics of radiology are based on "primum non nocere".

Characterization of a distinct Johnsongrass mosaic virus strain isolated from sorghum in Nigeria

A virus isolated from sorghum in Nigeria has been partially characterized. It was tested by enzyme-linked immunosorbent assay (ELISA) using antisera to Maize dwarf mosaic virus, Johnsongrass mosaic virus (JGMV), Sugarcane mosaic virus strain-MDB, Sorghum mosaic virus, and Zea mosaic virus. A partial host range, symptom phenotypes for selected sorghum lines, and the mass of the coat protein (CP) subunit was analyzed by sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and its amino acid (aa) sequence determined by time-of-flight mass spectrometry (TOFMS). The Nigerian isolate was positive in ELISA to only JGMV antiserum. It infected sorghum and smooth brome but not oat or johnsongrass. It caused necrosis in 12 of 13 tested sorghum lines, while the USA JGMV isolate caused necrosis in only one sorghum line. In SDS-PAGE, the mass of the Nigerian virus CP was 3,000 Da smaller than that of JGMV-MDO. Moreover, TOFMS analyses showed that, while residues 1-7 of the CP aa sequence were identical to those of JGMV (GenBank #A27631), and residues 57-293 were almost identical to residues 67-303 of JGMV, the intermediate region exhibited significant differences, including a 10 aa deletion. These data indicate that the virus should be considered a distinct isolate of JGMV (JGMV-N) and expands the known range of JGMV to Africa.

Biological and Molecular Variability Among High Plains virus Isolates

The High Plains virus (HPV), vectored by the wheat curl mite (WCM) (Aceria tosichella), causes a severe disease of maize (Zea mays) in the U. S. High Plains. In the present study, five HPV isolates from five states were separated from co-infecting Wheat streak mosaic virus and their molecular and biological variability studied. Molecular studies involved time-of-flight mass spectrometry (TOFMS) to determine amino acid sequence variability of the 32-kDa nucleoprotein (32 np) of the isolates. Biological studies involved testing the ability of the five HPV isolates to infect a maize line previously shown to have resistance. Inoculations of the HPV isolates were conducted using vascular puncture inoculation (VPI) and viruliferous WCM. TOFMS analyses demonstrated an 18-amino acid sequence in the isolates at the N-terminus of the 32 np, the presence of amino acid sequence differences among the isolates, and variability among amino acid sequences of the 32 np of some isolates. Three of the five HPV isolates infected the resistant maize inbred, B73, using VPI, and two of the same three HPV isolates infected this line using WCM inoculation, albeit low numbers of plants were infected by each technique.

Gravitational deposition in a rhythmically expanding and contracting alveolus

In a previous simulation, our laboratory demonstrated that the flow induced by a rhythmically expanding and contracting alveolus is highly complex (Haber S, Butler JP, Brenner H, Emanuel I, and Tsuda A, J Fluid Mech 405: 243-268, 2000). Based on these earlier findings, we hypothesize that the trajectories and deposition of aerosols inside the alveoli differ substantially from those previously predicted. To test this hypothesis, trajectories of fine particles (0.5-2.5 microm in diameter) moving in the foregoing alveolar flow field and simultaneously subjected to the gravity field were simulated. The results show that alveolar wall motion is crucial in determining the enhancement of aerosol deposition inside the alveoli. In particular, 0.5- to 1-microm-diameter particles are sensitive to the detailed alveolar flow structure (e.g., recirculating flow), as they undergo gravity-induced convective mixing and deposition. Accordingly, deposition concentrations within each alveolus are nonuniform, with preferentially higher densities near the alveolar entrance ring, consistent with physiological observations. Deposition patterns along the acinar tree are also nonuniform, with higher deposition in the first half of the acinar generations. This is a result of the combined effects of enhanced alveolar deposition in the proximal region of the acinus due to alveoli expansion and contraction and reduction in the number of particles remaining in the gas phase down the acinar tree. We conclude that the cyclically expanding and contracting motion of alveoli plays an important role in determining gravitational deposition in the pulmonary acinus.

The place of the thalamus in frontal cortical-basal ganglia circuits

The thalamus has long been thought to convey subcortical information to the cortex. Indeed, models of basal ganglia function attribute the primary role for the thalamus to a simple relay of information processed in the basal ganglia to the cortex. The thalamic nuclear groups that are associated primarily with this function are the ventral anterior and ventral lateral nuclei and the mediodorsal thalamic nucleus. However, recent studies have shown that the corticothalamic projection is important for the dynamics of the thalamocortical processing. Furthermore, the relay nuclei that carry basal ganglia output to the cortex have recently been shown to project back to the basal ganglia directly. These two recent developments indicate a more dynamic role for the thalamus in basal ganglia information processing than a passive relay.

Determination of the complete amino acid sequence for the coat protein of brome mosaic virus by time-of-flight mass spectrometry. Evidence for mutations associated with change of propagation host

Time-of-flight mass spectrometry (TOFMS) has been applied to determine the complete coat protein amino acid sequences of a number of distinct brome mosaic virus (BMV) isolates. Ionization was carried out by both electrospray ionization and matrix-assisted laser desorption/ionization (MALDI). After determining overall coat protein masses, the proteins were digested with trypsin or Lys-C proteinases, and the digestion products were analyzed in a MALDI QqTOF mass spectrometer. The N terminus of the coat protein was found to be acetylated in each BMV isolate analyzed. In one isolate (BMV-Valverde), the amino acid sequence was identical to that predicted from the cDNA sequence of the "type" isolate, but deviations from the predicted amino acid sequence were observed for all the other isolates analyzed. When isolates were propagated in different host taxa, modified coat protein sequences were observed in some cases, along with the original sequence. Sequencing by TOFMS may therefore provide a basis for monitoring the effects of host passaging on a virus at the molecular level. Such TOFMS-based analyses assess the complete profiles of coat protein sequences actually present in infected tissues. They are therefore not subject to the selection biases inherent in deducing such sequences from reverse-transcribed viral RNA and cloning the resulting cDNA.

Effect of endogenous beta-hydroxybutyrate on glucose metabolism in the diabetic rabbit brain: a (13)C-magnetic resonance spectroscopy study of [U-(13)C]glucose metabolites

The neurological consequences of diabetes mellitus have recently been receiving greater attention in both clinical and experimental settings. The deleterious effect of hyperglycemia and altered oxidative substrate availability on the diabetic brain is the subject of many studies. The aim of the present study was to examine the effect of the altered metabolic environment, namely, hyperglycemia and hyperketonemia, on glucose metabolism in the diabetic brain. More specifically, we examined the effect of diabetes on the glucose flux via the pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC) pathways and subsequent metabolism in the tricarboxylic acid cycles in neurons and glia. To this end, [U-(13)C]glucose was infused into the circulation of alloxan-induced diabetic young adult rabbits, and the [(13)C]glucose metabolites were subsequently studied in brain extracts by (13)C-NMR. Significantly elevated brain glucose levels were found. In the hyperketonemic rabbits, elevated cerebral levels of beta-hydroxybutyrate (beta-HBA) were found. Alterations in the labeling patterns of glutamine in the hyperketonemic group lead to the conclusion that the elevated beta-HBA levels inhibit glucose metabolism, mostly in glia. This results in accumulation of glucose in the diabetic brain. In addition, altered levels of glutamine, glutamate, and GABA were also attributed to the effect of beta-HBA on brain metabolism. The possible role of these metabolic perturbations in causing neurological damage remains to be investigated.

Energy fuel utilization by fetal versus young rabbit brain: a 13C MRS isotopomer analysis of [U-(13)C]glucose metabolites

The principle substrate for brain metabolism is glucose, which provides both energy and the carbon skeletons of glutamate and glutamine, via the TCA cycle. The existence of two distinct cerebral metabolic compartments, neurons and glia, involved in glutamate and glutamine synthesis, respectively, is a widely accepted concept. In previous work, the relative glucose flux via pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC) in adult rabbit brain, using 13C NMR isotopomer analysis of glutamate and glutamine, was quantified. In this work, manifestation of cerebral compartmentation in the near-term fetal rabbit was investigated, using the above approach. Following infusion of [U-13C]glucose into maternal circulation (1 mg/kg per min) for 60-70 min, fetal brains were excised and brain extracts were studied by 13C NMR. The labelling patterns of fetal cerebral metabolites differed from those observed in the young adult brain. The most significant differences were found for glutamine labelling patterns. We suggested that these differences are a result of increased utilization of non-labeled fuels, mainly beta-hydroxybutyrate (beta-HBA) in the glia, the site of glutamine synthesis. In addition, we have shown that acute exposure to elevated beta-HBA levels leads to increased uptake, but not utilization, into the fetal rabbit brain; no increase in uptake is observed in the adult brain. We have also demonstrated that during short-term starvation, although no changes are detected in plasma and cerebral glucose levels in the fetal and young adult brain, amino acid levels and energy metabolism are altered in the young adult brain.

Effect of acute insulin-induced hypoglycemia on fetal versus adult brain fuel utilization, assessed by (13)C MRS isotopomer analysis of [U-(13)C]glucose metabolites

Tight glycemic control during diabetic pregnancy has been shown to significantly reduce the occurrence of congenital malformations and other effects of maternal diabetes on the offspring. However, intensive insulin therapy often causes recurring acute maternal hypoglycemia, which has been found to be harmful to the developing fetus, although the mechanisms involved are not clear. The aim of our work was to study the effect of acute insulin-induced maternal hypoglycemia on glucose metabolism in the fetal brain. To this end, near-term pregnant New Zealand rabbits were rendered hypoglycemic, and [U-(13)C]glucose was infused into maternal circulation. The metabolic fate of the (13)C-labeled glucose was then studied in fetal brain extracts by (13)C NMR isotopomer analysis, together with conventional biochemical assays of glucose and lactate levels in both plasma and brain. For comparison [U-(13)C]glucose was also administered to insulin-induced hypoglycemic young adult rabbits. Our results showed that while plasma glucose levels were significantly reduced (approximately 70%) relative to controls, no changes in cerebral glucose levels could be detected. Lactate levels were found to be significantly decreased in hypoglycemic fetal plasma and brain. No differences in lactate levels between control and hypoglycemic young rabbit plasma and brain were observed. These differences were attributed to the utilization of lactate as an energy substrate in the fetal brain, but not in the adult brain. Higher relative (13)C enrichments of most glucose metabolites, except lactate, in the hypoglycemic fetal and young rabbit brains, observed by (13)C NMR, stem from reduced endogenous plasma glucose pools, thereby diluting the labeled glucose to a lower extent. The relative glucose (or glucose-derived lactate) flux via the pyruvate carboxylase and pyruvate dehydrogenase pathways (PC/PDH ratio) was not altered under hypoglycemic conditions in the fetal brain for both glutamine and glutamate, but significantly increased in the adult brain for both glutamine and glutamate. The presented data indicate the ability of the fetal brain to maintain energy metabolism during acute hypoglycemia, via lactate utilization. The increase in the adult PC/PDH ratio was suggested by us to stem from increased PC activity, in order to replenish TCA cycle intermediates.

Characterization of a novel potyvirus isolated from maize in Israel

A potyvirus (proposed name of Zea mosaic virus [ZeMV]) isolated from maize in Israel was analyzed by serology, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of capsid proteins, symptomatology, and sequencing. Parts of the nuclear inclusion b, coat protein, and 3' regions were sequenced; the amino acid sequence of ZeMV capsid was determined by time-of-flight mass spectrometry (TOFMS). The results of these analyses were compared with those of similar analyses of the following potyviruses: Maize dwarf mosaic virus (MDMV), Sugarcane mosaic virus strain MDB (SCMV-MDB), Johnsongrass mosaic virus(JGMV), Sorghum mosaic virus (SrMV), and an isolate of MDMV from Israel. Indirect enzyme-linked immunosorbent assay using ZeMV antiserum detected only ZeMV, and reciprocal tests using MDMV, JGMV, or SrMV antisera failed to detect ZeMV. ZeMV cross-reacted weakly when SCMV-MDB antiserum was used. The mass of ZeMV capsid was determined to be 36,810 Da by SDS-PAGE and 34,216 Da by TOFMS. The ZeMV systemically infected johnsongrass (Sorghum halepense), but did not infect oat (Avena sativa), pearl millet (Pennisetum glaucum), barley (Hordeum vulgare), or rye (Secale cereale). Necrosis was caused in 19 sorghum lines by SrMV, in 15 by ZeMV, in 14 by MDMV, and in 5 by JGMV and SCMV-MDB. The nucleic acid and amino acid sequences of ZeMV clearly showed that it is not a strain of JGMV, MDMV, SCMV, or SrMV.

Immunocytochemical localization of the dopamine transporter in human brain

The dopamine transporter (DAT) was localized in normal human brain tissue by light microscopic immunocytochemistry by using highly specific monoclonal antibodies. Regional distribution of DAT was found in areas with established dopaminergic circuitry, e.g., mesostriatal, mesolimbic, and mesocortical pathways. Mesencephalic DAT-immunoreactivity was enriched in the dendrites and cell bodies of neurons in the substantia nigra pars compacta and ventral tegmental area. Staining in the striatum and nucleus accumbens was dense and heterogeneous. Mesocortical DAT immunoreactivity in motor, premotor, anterior cingulate, prefrontal, entorhinal/perirhinal, insular, and visual cortices was detected in scattered varicose and a few nonvaricose fibers. Varicose fibers were relatively enriched in the basolateral and central subnuclei of amygdala, with sparser fibers in lateral and basomedial subnuclei. Double-labeling studies combining DAT and tyrosine hydroxylase (TH) immunostaining in the ventral mesencephalon showed two subpopulations of dopaminergic neurons differentiated by the presence or absence of DAT-immunoreactivity in the A9 and A10 cell groups. In other dopaminergic cell groups (All, A13-A15), TH-positive hypothalamic neurons showed no detectable DAT-immunoreactivity. However, fine DAT-immunoreactive axons were scattered throughout the hypothalamus, particularly concentrated along the medial border, with more coarse axons present along the lateral border. These findings demonstrate that most mesotelencephalic dopamine neurons of human brain express high levels of DAT throughout their entire somatodendritic and axonal domains, whereas a smaller subpopulation of mesencephalic dopamine cells and all hypothalamic dopamine cell groups examined express little or no DAT. These data indicate that different subpopulations of dopaminergic neurons use different mechanisms to regulate their extracellular dopamine levels.

Pharmacotherapy of photorefractive keratectomy

PURPOSE

To compare the pharmacotherapeutic practices of high-volume photorefractive keratectomy (PRK) surgeons with suggested practices gleaned from the current literature.

SETTING

York Finch Eye Associates, Toronto, Canada.

METHODS

Seventy-five ophthalmic surgeons believed by the authors to do a high-volume of PRKs were surveyed over the summer of 1994 about their pharmacotherapeutic practices. The results were compared with suggested practices extracted from a review of the current literature.

RESULTS

Relatively consistent approaches to the management of post-PRK pain and prevention of acute post-PRK subepithelial infiltrative keratitis were reported. The administration of topical steroids after PRK was almost universally employed. Post-PRK analgesia was most commonly achieved with nonsteroidal anti-inflammatory drugs (NSAIDs) and a soft contact lens, but surgeons were not convinced of the benefits of long-term NSAID administration to control myopic regression and haze. There seemed to be no agreed-on solution to the infrequent problems of severe haze and regression and steroid-induced elevated intraocular pressure after PRK; however, many useful suggestions for the management of these problems were proposed.

CONCLUSION

In general, high-volume PRK surgeons use topical steroids, NSAIDs, and a soft contact lens in the immediate postoperative period, although they are uncertain about the long-term effectiveness of NSAIDs in controlling regression and haze.

Aerosol transport and deposition in the rhythmically expanding pulmonary acinus

Little is known about factors controlling the dynamics of aerosol dispersion and deposition in the lung periphery, though this knowledge becomes increasingly important in many fields such as environmental and occupational exposure, diagnostic applications, and therapeutic deliver of drugs via aerosols. For the last several years, we have been studying aerosol behavior in the pulmonary acinus, where the airway structure and the associated fluid mechanics are distinctly different from those in the conducting airways. Our major research efforts have been focused on the basic physics underlying acinar fluid mechanics and particle dynamics, which are likely to be conditioned by the two key geometric factors of acinar airways: structural alveolation and rhythmic expansion and contraction of the alveolar walls. A combination of computational and experimental analyses revealed that due to these unique geometric features acinar flow can be extremely complex despite the low Reynolds number, and can have substantial effects on particle dynamics. In particular, chaotic mixing can occur in the lung periphery. In the course of such a mixing process, the inhaled aerosol particles quickly mix with the residual alveolar gas in a manner that is radically different from the previously considered classical diffusion process. The objective of this paper is to briefly review our current understanding of these processes, to discuss existing deposition models, and to describe our ongoing research efforts toward a basic understanding of aerosol behavior in the pulmonary acinus.

Tracing intrinsic fiber connections in postmortem human brain with WGA-HRP

Modern methods for tracing central nervous system pathways depend largely on active axonal transport mechanisms and are carried out in in vivo animal experiments. This report describes the ability to trace axons and label cell bodies in postmortem human material, using injections of wheat germ agglutinin horseradish peroxidase. Furthermore, it demonstrates the compatibility of this method with immunocytochemical techniques for localizing neurotransmitters. Thus it is possible to study the intrinsic circuitry or short connections in brain regions such as cortex in both normal and pathological material, and, using double label methods, determine the transmitter systems involved. It also raises the issue of the mechanisms which are involved in the movement of the tracer molecule.

Anatomical relationship between the basal ganglia and the basal nucleus of Meynert in human and monkey forebrain

Previous immunohistochemical studies have provided evidence that the external segment of the globus pallidus extends ventrally beneath the transverse limb of the anterior commissure into the area of the substantia innominata. Enkephalin-positive staining in the form of "woolly fibers" has been used as a marker for the globus pallidus and its ventral extension. Acetylcholinesterase staining of both fibers and cell bodies, frequently used as a marker for the basal nucleus of Meynert, is also found in the area of the substantia innominata. This study describes the differential distribution of enkephalin-positive woolly fibers and acetylcholinesterase staining on adjacent sections in both the monkey and human basal forebrain area in an attempt to define the relationship between the basal ganglia and the basal nucleus of Meynert. The results show that while both occupy large regions of the basal forebrain, they overlap very little. In both species investigated, dense concentrations of acetylcholinesterase-positive neurons lie, for the most part, outside the boundaries of the pallidal fibers. However, some scattered acetylcholinesterase cells do lie within the confines of the dorsal pallidum, and a more prominent group is found in the subcommissural ventral pallidum. These cells may constitute a group separate from the more densely packed acetylcholinesterase-positive cells in woolly fiber-free regions in that they may receive direct striatal input.

Evaluation of Arizona Health Care Cost Containment System, 1984-85

In this article, we describe the evaluation of the Arizona Health Care Cost Containment System (AHCCCS), Arizona's alternative to the acute care portion of Medicaid. We provide an assessment of implementation of the program's innovative features during its second 18 months of operation, from April 1984 through September 1985. Included in the evaluation are assessments of the administration of the program, provider relations, eligibility, enrollment and marketing, information systems, quality assurance and member satisfaction activities, the relationship of the county governments to AHCCCS, the competitive bidding process, and the plans and their financial status.

Fetal neuronal grafts in monkeys given methylphenyltetrahydropyridine

Fetal substantia nigra cells of two different gestational ages were successfully transplanted into the brains of three methylphenyltetrahydropyridine-treated monkeys with severe parkinsonian motor and behavioural deficits. Functional improvement continued for 10 weeks after cell grafts into the striata of two monkeys with substantial numbers of tyrosine-hydroxylase-positive fetal neurons at necropsy. Behavioural improvement was correlated with increases in cerebrospinal fluid (CSF) homovanillic acid (HVA) concentrations after the transplants. A control monkey with inappropriately placed transplanted cells of an earlier gestational age remained severely parkinsonian and died during a similar period. CSF HVA fell slightly in this monkey from the low level seen before the transplants. Fetal dopamine neurons of two different gestational ages appear to survive transplantation in primates and have biochemical and functional effects.

Antigen presentation by hapten-specific B lymphocytes. II. Specificity and properties of antigen-presenting B lymphocytes, and function of immunoglobulin receptors

The studies described in this paper were designed to examine the ability of hapten-binding murine B lymphocytes to present hapten-protein conjugates to protein antigen-specific, Ia-restricted T cell hybridomas. BALB/c B cells specific for TNP or FITC presented hapten-modified proteins (TNP-G1 phi, TNP-OVA, or FITC-OVA) to the relevant T cell hybridomas at concentrations below 0.1 microgram/ml. Effective presentation of the same antigens by B lymphocyte-depleted splenocytes, and of unmodified proteins by either hapten-binding B cells or Ig spleen cells, required about 10(3)-to 10(4)-fold higher concentrations of antigen. The use of two different haptens and two carrier proteins showed that this extremely efficient presentation of antigen was highly specific, with hapten specificity being a property of the B cells and carrier specificity of the responding T cells. The presentation of hapten-proteins by hapten-binding B lymphocytes was radiosensitive and was not affected by the depletion of plastic-adherent cells, suggesting that conventional APCs (macrophages or dendritic cells) are not required in this phenomenon. Antigen-pulsing and antibody-blocking experiments showed that this hapten-specific antigen presentation required initial binding of antigen to surface Ig receptors. Moreover, linked recognition of hapten and carrier determinants was required, but these recognition events could be temporally separated. Finally, an antigen-processing step was found to be necessary, and this step was disrupted by ionizing radiation. These data suggest a role for B cell surface Ig in providing a specific high-affinity receptor to allow efficient uptake or focusing of antigen for its subsequent processing and presentation to T lymphocytes.

Antigen presentation by hapten-specific B lymphocytes. II. Specificity and properties of antigen-presenting B lymphocytes, and function of immunoglobulin receptors

The studies described in this paper were designed to examine the ability of hapten-binding murine B lymphocytes to present hapten-protein conjugates to protein antigen-specific, Ia-restricted T cell hybridomas. BALB/c B cells specific for TNP or FITC presented hapten-modified proteins (TNP-G1 phi, TNP-OVA, or FITC-OVA) to the relevant T cell hybridomas at concentrations below 0.1 microgram/ml. Effective presentation of the same antigens by B lymphocyte-depleted splenocytes, and of unmodified proteins by either hapten-binding B cells or Ig spleen cells, required about 10(3)-to 10(4)-fold higher concentrations of antigen. The use of two different haptens and two carrier proteins showed that this extremely efficient presentation of antigen was highly specific, with hapten specificity being a property of the B cells and carrier specificity of the responding T cells. The presentation of hapten-proteins by hapten-binding B lymphocytes was radiosensitive and was not affected by the depletion of plastic-adherent cells, suggesting that conventional APCs (macrophages or dendritic cells) are not required in this phenomenon. Antigen-pulsing and antibody-blocking experiments showed that this hapten-specific antigen presentation required initial binding of antigen to surface Ig receptors. Moreover, linked recognition of hapten and carrier determinants was required, but these recognition events could be temporally separated. Finally, an antigen-processing step was found to be necessary, and this step was disrupted by ionizing radiation. These data suggest a role for B cell surface Ig in providing a specific high-affinity receptor to allow efficient uptake or focusing of antigen for its subsequent processing and presentation to T lymphocytes.

Numerical analysis of the thermochemical tooth damage induced by laser radiation

A numerical model is developed to predict zones of thermochemical tooth damage induced by laser radiation. Particular attention is devoted to pulp denaturation, enamel fracture and caries sterilization treatment dependence on laser energy and other beam parameters.

Evaluation of the Arizona health care cost-containment system

This article evaluates Arizona's alternative to the acute portion of Medicaid, the Arizona Health Care Cost-Containment System (AHCCCS), during its first 18 months of operation from October 1982 through March 1984. It focuses on the program's implementation and describes and evaluates the program's innovative features. The features of the program outlined in the original AHCCCS legislation included: Competitive bidding, prepaid capitation of providers, capitation of the State by the Health Care Financing Administration, assignment of gatekeepers, beneficiary copayment, private administration, inclusion of private and public employees and county financed long-term care. An assessment of implementation during the second 18 months of the program reporting on more recent developments and is now being prepared by SRI International.

Epidemiology, health policy, and resource allocation: the Israeli perspective

Israel represents a developed country as far as demand and consumption of health services are concerned. The analysis of the Israeli health system reveals a significant trend of expansion in the intensity and the utilization of health services as well as an accelerated development of sophisticated technology, while the percentage of Gross National Product used for health expenditure remained constant and even decreased. Competing needs, reflecting population growth, a rapid aging process, new areas of treatment, and changes in use of health services, illustrate the aggravating issue of setting priorities. The permanent dilemma of the health system is oscillation between opposite trends: enlargement of public eligibility and technological capabilities and economic reduction and budget limitations. Is there a possibility that the insufficiencies of the system are built into patterns of thinking of those in the system, into its structure, and into its organization of health services delivery? Does the formulation of health policy influence, in terms of the outcomes of the system, priorities and allocation of resources? Does the process of decisionmaking reflect in an appropriate manner the epidemiologic data? Under the objective constraints, decisionmaking and health policy formulation become critical determinants of the ability to cope more efficiently and effectively with growing and changing needs. The authors suggest an alternative strategy of health decisionmaking that is more instrumental in order to prevent setbacks and to open new horizons for the future.

The distribution of enkephalin immunoreactive neuronal cell bodies in the monkey brain: preliminary observations

The distribution of enkephalin immunoreactive cell bodies was studied in the central nervous system of colchicine-treated monkeys. They followed a distribution pattern similar to enkephalin immunoreactive nerve fibers and terminal fields, and were found throughout much of the spinal cord and brain. Large numbers of enkephalin immunoreactive cell bodies were seen in the brainstem, hypothalamus and in telencephalic nuclear areas. In most regions, the distribution of enkephalin immunoreactive cell bodies in the monkey brain was similar to that reported for the rat.

The distribution of enkephalin immunoreactive fibers and terminals in the monkey central nervous system: an immunohistochemical study

Using immunohistochemical techniques, the distribution of met-enkephalin fibers and terminals was studied in the central nervous system of adult old-world monkeys. Areas which showed the greatest density of immunoreactivity included substantia gelatinosa, nucleus tractus solitarius, nucleus parabrachialis, substantia nigra, median eminence, globus pallidus (external segment), patches within the striatum and the region of nucleus accumbens and the olfactory area. Striking and discrete zones of enkephalin immunoreactive fibers and terminals which did not conform to known nuclear boundaries were observed in the latter areas. The distribution of enkephalin in the monkey is compared to what has been described in the rat central nervous system. In general, the two species are similar, however, differences were observed in some areas including the hypoglossal nucleus, substantia nigra and in the region of the nucleus accumbens and olfactory area. The results are discussed with regard to the possible functional significance of enkephalin localization in regions related to regulation of pain, mood, and autonomic function.