Developments in Time-Division Multiplexing of X-ray Transition-Edge Sensors.

Time-division multiplexing (TDM) is a mature scheme for the readout of arrays of transition-edge sensors (TESs). TDM is based on superconducting-quantum-interference-device (SQUID) current amplifiers. Multiple spectrometers based on gamma-ray and X-ray microcalorimeters have been operated with TDM readout, each at the scale of 200 sensors per spectrometer, as have several astronomical cameras with thousands of sub-mm or microwave bolometers. Here we present the details of two different versions of our TDM system designed to read out X-ray TESs. The first has been field-deployed in two 160-sensor (8 columns × 20 rows) spectrometers and four 240-sensor (8 columns × 30 rows) spectrometers. It has a three-SQUID-stage architecture, switches rows every 320 ns, and has total readout noise of 0.41 µΦ0/√Hz. The second, which is presently under development, has a two-SQUID-stage architecture, switches rows every 160 ns, and has total readout noise of 0.19 µΦ0/√Hz. Both quoted noise values are non-multiplexed and referred to the first-stage SQUID. In a demonstration of this new architecture, a multiplexed 1-column × 32-row array of NIST TESs achieved average energy resolution of 2.55±0.01 eV at 6 keV.

Effects of grazing residues or feeding corn from a corn rootworm-protected hybrid (MON 863) compared with reference hybrids on animal performance and carcass characteristics.

One grazing and two feeding experiments were conducted to compare the feeding value of corn residue or corn grain from a genetically enhanced corn hybrid (corn rootworm-protected; event MON 863) with nontransgenic, commercially available, reference hybrids. In Exp. 1, two 13.7-ha fields, containing corn residues from either a genetically enhanced corn root-worm-protected hybrid (MON 863), or a near-isogenic, nontransgenic control hybrid (CON) were divided into four equal-sized paddocks. Sixty-four steer calves (262 +/- 15 kg) were stratified by BW and assigned randomly to paddock to achieve a stocking rate of 0.43 ha/steer for 60 d, with eight steers per paddock and 32 steers per hybrid. A protein supplement was fed at 0.45 kg/steer daily (DM basis) to ensure protein intake did not limit performance. Steer ADG did not differ (P = 0.30) between steers grazing the MON 863 (0.39 kg/d) and CON (0.34 kg/d) corn residues for 60 d. The four treatments for the feeding experiments (Exp. 2 and 3) included two separate reference hybrids, the near-isogenic control hybrid (CON), and the genetically enhanced hybrid (MON 863) resulting in two preplanned comparisons of CON vs. MON 863, and MON 863 vs. the average of the reference hybrids (REF). In Exp. 2, 200 crossbred yearling steers (365 +/- 19 kg) were fed in 20 pens, with five pens per corn hybrid. In Exp. 3, 196 crossbred yearling steers (457 +/- 33 kg) were fed in 28 pens, with seven pens per corn hybrid. In Exp. 2, DMI and G:F did not differ (P > 0.10) between MON 863 and CON; however, steers fed MON 863 had a greater (P = 0.04) ADG than steers fed CON. Gain efficiency was greater (P = 0.05) for MON 863 cattle than for REF cattle in Exp. 2, but other performance measurements (DMI and ADG) did not differ (P > 0.10) between MON 863 and REF. No differences (P > 0.10) were observed for performance (DMI, ADG, and G:F) between MON 863 and CON or MON 863 and REF in Exp. 3. In terms of carcass characteristics, no differences (P > 0.10) were observed between MON 863 and CON, as well as MON 863 and REF, for marbling score, LM area, or 12th rib fat thickness in both Exp. 2 and 3. Overall, performance was not negatively affected in the corn residue grazing or feedlot experiments, suggesting the corn rootworm-protected hybrid (event MON 863) is similar to conventional, nontransgenic corn grain and residues when utilized by beef cattle.

Effect of feeding glyphosate-tolerant (roundup-ready events GA21 or nk603) corn compared with reference hybrids on feedlot steer performance and carcass characteristics.

Three experiments were conducted to compare the feeding value of genetically enhanced corn (Roundup Ready corn events GA21 and nk603) with nontransgenic hybrids. The four treatments included two separate reference hybrids (REF), the near-isogenic control hybrid (CON), and the genetically enhanced corn (RR), resulting in two preplanned comparisons of CON vs. RR and RR vs. the average of REF. In Exp. 1 (RR event GA21), 175 steers (BW = 427 kg) were fed in 25 pens with seven pens per corn hybrid, except CON, which contained four pens due to limited quantities of that hybrid. In Exp. 2 (RR event nk603), 196 steers (BW = 420 kg) were fed in 28 pens with seven pens per corn. In Exp. 3 (RR event nk603), 200 steers were fed in 20 pens, with a similar treatment design to Exp. 2 and five pens per corn. All experiments were conducted as completely randomized designs and utilized corn produced at University of Illinois (Exp. 1 and 2) and University of Nebraska (Exp. 3) research farms under identity-preserved protocols. In all experiments, DMI, ADG, and feed efficiency were similar (P > 0.30) between RR and REF. In Exp. 1 and Exp. 2, RR was not different (P > 0.25) than CON for growth performance. In Exp. 3, RR was not different from CON for ADG and DMI (P > 0.15) or for feed efficiency (P = 0.08). No differences were observed between RR and CON or RR and REF for carcass weight, longissimus dorsi area, and marbling scores in any of the experiments. Subtle differences were observed between RR and either CON or REF for fat depth in each experiment; however, cattle fed RR were not consistently greater and varied from either the CON or the REF (but not both contrasts) within an experiment. Based on these results, insertion of glyphosate-tolerant genes had no significant effect on nutritive quality of corn. Performance and carcass characteristics were not influenced, which suggests that Roundup Ready corn is similar to conventional, nontransgenic corn when fed to finishing feedlot cattle.

Adult attention-deficit/hyperactivity disorder: neuropsychological correlates and clinical presentation.

We compared the neuropsychological test performance of adult ADHD patients to the neurocognitive profiles of control subjects recruited from the general population. We administered a neuropsychological test battery consisting of measures considered sensitive to either orbitofrontal or dorsolateral-prefrontal (DLPF) dysfunction. Orbitofrontal hypoarousal is associated with behavioral disinhibition and a relative indifference to punishment. The DLPF region may function as a central executive system. Indeed, DLPF dysfunction may underlie many of the cardinal symptoms associated with ADHD. We tested the following hypotheses: (1) adult subjects meeting DSM-IV criteria for ADHD, predominantly hyperactive-impulsive type, would display neuropsychological deficits on tasks sensitive to orbitofrontal dysfunction; (2) adult subjects meeting DSM-IV criteria for ADHD, predominantly inattentive type, would perform poorly on measures sensitive to DLPF dysfunction; and (3) adult subjects meeting DSM-IV criteria for ADHD, combined type, would exhibit performance deficits on orbitofrontal measures and on DLPF tasks. Results partially confirmed our hypotheses. Subtyping ADHD patients revealed important group differences. Distinct neurocognitive and clinical profiles were observed.

Lactobacillus endocarditis: a case report of outpatient management.

A case of infective endocarditis due to Lactobacillus is presented. The diagnosis was established by positive blood cultures and transesophageal (but not transthoracic) echocardiography. The patient was cured with outpatient ceftriaxone therapy.

Aging differentially alters forms of long-term potentiation in rat hippocampal area CA1.

Long-term potentiation (LTP) of the Schaffer collateral/commissural inputs to CA1 in the hippocampus was shown to consist of N-methyl-D-aspartate receptor (NMDAR) and voltage-dependent calcium channel (VDCC) dependent forms. In this study, the relative contributions of these two forms of LTP in in vitro hippocampal slices from young (2 mo) and old (24 mo) Fischer 344 rats were examined. Excitatory postsynaptic potentials (EPSP) were recorded extracellularly from stratum radiatum before and after a tetanic stimulus consisting of four 200-Hz, 0.5-s trains given 5 s apart. Under control conditions, a compound LTP consisting of both forms was induced and was similar, in both time course and magnitude, in young and old animals. NMDAR-dependent LTP (nmdaLTP), isolated by the application of 10 microM nifedipine (a voltage-dependent calcium channel blocker), was significantly reduced in magnitude in aged animals. The VDCC dependent form (vdccLTP), isolated by the application of 50 microM D,L-2-amino-5-phosphonvalerate (APV), was significantly larger in aged animals. Although both LTP forms reached stable values 40-60 min posttetanus in young animals, in aged animals vdccLTP increased and nmdaLTP decreased during this time. In both young and old animals, the sum of the two isolated LTP forms approximated the magnitude of the compound LTP, and application of APV and nifedipine or genestein (a tyrosine kinase inhibitor) together blocked potentiation. These results suggest that aging causes a shift in synaptic plasticity from NMDAR-dependent mechanisms to VDCC-dependent mechanisms. The data are consistent with previous findings of increased L-type calcium current and decreased NMDAR number in aged CA1 cells and may help explain age-related deficits in learning and memory.

Flow cytometric cell sorting combined with molecular chimerism analysis to detect minimal recurrent leukemia: good news and bad news.

Allogeneic BMT offers the possibility of cure for a variety of hematopoietic malignancies, but disease relapse remains a major cause of treatment failure. This report describes two cases in which flow cytometric cell sorting (FACS) and molecular chimerism analysis were combined to increase the sensitivity of minimal residual disease (MRD) detection. In the first case this approach was used to demonstrate that a suspicious phenotype was not recurrent leukemia, thus preventing the use of potentially toxic therapy. In the second case the recurrence of a leukemia which was undetectable by conventional analysis was confirmed. The potential benefits of combining these MRD detection methods are discussed.

Trafficking of major histocompatibility complex class II molecules through intracellular compartments containing HLA-DM.

The endosomal site(s) where MHC class II molecules become competent to bind antigenic peptide has not been completely characterized. We identified endocytic compartments through which newly synthesized MHC class II molecules move prior to their expression on the plasma membrane. The compartments co-sediment with lysosomes in the most dense regions of Percoll gradients. The appearance of proteolytic fragments of the invariant chain (I chain), namely leupeptin-induced proteins (LIPs) and class-II-associated invariant chain peptides (CLIP), in this region of the gradient suggests that the release of MHC class II molecules from I chain association occurs within these vesicles. The formation of SDS-stable alpha beta dimers indicated that MHC class II molecules contained within these compartments are receptive to peptide binding. A majority of the HLA-DM protein was found in the same region of the Percoll gradient, consistent with its established function in MHC class-II-restricted antigen presentation. Immunoelectron micrographs of dense-sedimenting compartments indicated that I chain, MHC class II, and DM molecules are contained within both multivesicular and multilamellar vesicles. The final stages of I chain dissociation from MHC class II molecules and DM-mediated peptide loading probably occur in these compartments.

Assembly and intracellular transport of HLA-DM and correction of the class II antigen-processing defect in T2 cells.

MHC class II molecules expressed in T2 cells fail to acquire a normal complement of endocytically generated peptides. The defect is repaired by introducing HLA-DMA and HLA-DMB cDNA expression vectors, determined by the restoration of SDS stability of class II alpha beta dimers, restoration of a normal conformation for HLA-DR3 as detected by a monoclonal antibody, and by a reduction in class II-associated invariant chain peptides. The intracellular distribution of class II and invariant chain molecules is also restored to that of wild-type cells. The HLA-DMA and HLA-DMB products appear to form a heterodimer that, although transported at least to the medial Golgi, is not expressed at the cell surface. These findings are consistent with HLA-DM functioning intracellularly to facilitate class II-restricted antigen processing.

Persistent fever in association with infective endocarditis.

Fever persisting despite adequate antimicrobial therapy for endocarditis can be an ominous sign. To evaluate the significance of persistent fever in this situation, we reviewed the records of patients at three hospital affiliates of Albert Einstein College of Medicine. Twenty-six patients with 27 episodes of endocarditis and fever lasting for > or = 2 weeks despite appropriate antimicrobial therapy were identified and compared with a matched cohort of 26 patients with endocarditis but without prolonged fever. The median duration of fever in the former group was 35 days. Cardiac infection caused fever in 13 of these patients, seven of whom had myocardial abscesses. Additional causes of infection included drug treatment, nosocomial transmission of pathogens, and pulmonary emboli. Sixteen patients required cardiac surgery (seven on an emergent basis), whereas only two controls underwent such a procedure (P < .001). Twenty-two patients with persistent fever and five controls developed nosocomial complications (P < .001). Six patients with fever died, five from endocarditis-related complications. Thus persistent fever often indicates complicated endocarditis. We present an approach for the evaluation of the patients affected by this condition.

Neural cell adhesion molecule in aged mouse muscle.

Expression of the neural cell adhesion molecule was compared in endplate and non-endplate regions of skeletal muscles of mature and old CBF-1 mice, in order to determine whether age-related changes in neuromuscular morphology were correlated with age changes in neural cell adhesion molecule expression. Three muscles were examined: two (soleus and sternomastoid) showed age-related regionalization of nerve terminals as one manifestation of increased synaptic remodelling while the third (diaphragm) did not. Relative neural cell adhesion molecule content in these muscles was measured by densitometry of immunoblots after concentration by affinity chromatography. Expression of the major 140,000 mol. wt form of neural cell adhesion molecule, which was most abundant in the endplate region, was increased in sternomastoid and soleus of old compared to adult mouse, but was unchanged with age in diaphragm. A 70,000-80,000 mol. wt presumably proteolytic polypeptide fragment of neural cell adhesion molecule was increased in immunoblots of all old muscles. Immunocytochemical studies of skeletal muscles showed no difference in neural cell adhesion molecule cellular distribution in mature vs old mice, but in motor nerve of sternomastoid, the number of neural cell adhesion molecule-positive nerve fibers was increased in old mice. Several lines of evidence indicated that partial denervation was rare in old CBF-1 mice, and therefore could not account for the findings above. Selective increase of 140,000 mol. wt neural cell adhesion molecule expression in the junctional regions of those muscles of old mice which show neuromuscular remodelling indicates that this adhesion molecule may play a role in the age-related instability of motor nerve terminals.

Compensatory plasticity of aging at the neuromuscular junction.

Several age-related phenomena observed at the neuromuscular junction (NMJ) can be viewed as adaptations to cellular deficits. These compensatory mechanisms, which maintain functional and morphologic integrity, are those present in the adult animal. In the study of compensatory mechanisms with age, the choice of an appropriate animal model is important. Three adaptations are discussed: maintenance or increase of transmitter release despite reduced supply of synaptic vesicles; functional reactive sprouting after partial denervation despite reduced axonal transport; and maintenance of nerve terminal integrity in the face of increased outgrowth and retraction. In all cases, successful adaptation in old animals is obtained at the expense of a more fragile system. Either the compensations themselves or the resulting vulnerability may alter the reactions of the aging nervous system to changes in external and internal milieu.

Plasticity of presynaptic and postsynaptic elements of neuromuscular junctions repeatedly observed in living adult mice.

In order to assay the extent of ongoing synaptic remodelling in adult mouse neuromuscular junctions, dynamic structural changes of identified neuromuscular junctions were monitored in vivo over periods up to three months. Nerve terminal outgrowths as small as 1 micron were detectable with a new fluorescent tetanus toxin C-fragment stain combined with fluoresceinated alpha-bungarotoxin to stain postsynaptic acetylcholine receptors. With limited illumination, the new stain did not affect miniature endplate potential frequency, nor morphometric parameters of repeatedly observed neuromuscular junctions. At each observation, areas of presynaptic nerve terminal extending beyond underlying acetylcholine receptor ('preprojections'), and areas of acetylcholine receptor without overlying nerve terminal ('postprojections') were measured. Regions of the neuromuscular junction in which nerve terminal-postsynaptic acetylcholine receptor complexes either 'lengthened' or 'shortened' between observations were also measured. The total area of pre- and postprojections (relative to total junctional area) remained the same over three months but most had been replaced; only 20% of preprojections gave rise to lengthenings, the rest retracted or were unchanged. Lengthening and shortening of branches were about 1-2% of junctional area per month. These more permanent changes occurred against a background of ongoing transient nerve terminal outgrowth and retraction (which constituted 80% of all neuromuscular junction shape changes from one observation to the next, compared with 20% for the postsynaptic component). Breaks in the continuity of the underlying acetylcholine receptor were also observed between observations as were instances where acetylcholine receptor continuity was re-established. A newly observed form of plasticity was a shift in position and angle of pre-existing branches. Establishment of new acetylcholine receptor-positive synaptic regions was mostly preceded by nerve terminal outgrowth on the previous observation. In animals in which spontaneous wheel-running increased locomotor activity approximately tenfold over a period of 35 days, the findings were identical to those in unexercised mice. In summary, in the adult neuromuscular junction, the nerve terminal, not the postsynaptic component, is the dynamic entity, continually changing shape on the scale of micrometers, with relatively small permanent changes. These ongoing exploratory excursions may supply the substrate for synaptic plasticity, which would involve regulation of the dynamics or stability of nerve outgrowth.

Mode of enlargement of young mouse neuromuscular junctions observed repeatedly in vivo with visualization of pre- and postsynaptic borders.

The dynamics of structural remodelling during growth of synapses was studied in identified living neuromuscular junctions observed three times at four-day intervals in three- to five-week-old mice. Nerve terminals and acetylcholine receptors in pectineus muscle were stained and visualized with fluorescent ligands of tetanus toxin C-fragment and alpha-bungarotoxin, respectively. In most observations, about 2.5% of nerve terminal area was observed without underlying acetylcholine receptor (termed 'preprojection'), and about 0.4% of acetylcholine receptor without overlying nerve terminal ('post-projection'). Neither overall synaptic growth nor prevalence of pre- and postprojections was affected by repeated observation. In sequential observations, about 80% of the preprojection area at one observation had acquired underlying acetylcholine receptor four days later, while 20% retracted or showed no change. Although approximately one-half of postprojections were also precursors of synaptic regions, their absolute contribution to synaptic growth was small, and some had originated from nerve terminal retraction. Eight per cent of the disparities between pre- and postsynaptic components in second or third observations were the result of nerve terminal outgrowth or retraction. In the four-day intervals, there was about 7.5% lengthening but also about 3% shortening of synaptic area. Preprojectional induction of acetylcholine receptor accounted for at least 25% of lengthening, and apparent concurrent growth at ends or sides of branches accounted for most of the rest (although level of resolution limits this conclusion). Only about 10% of lengthening was attributable to central intercalary growth. In summary, the pectineus neuromuscular junction grows mainly by nerve terminal outgrowth giving rise four days later to underlying acetylcholine receptor and by conjoint lengthening of synaptic complexes but with relatively little contribution by initial acetylcholine receptor extension or intercalary growth. Growth of the neuromuscular junction is not monotonic: nerve terminals retract and synaptic branches shorten as net lengthening proceeds. Compared with non-growing adult neuromuscular junctions, nerve terminal preprojections in growing neuromuscular functions are more prevalent and more likely to give rise to new synaptic regions.

Differential effects of age on neuromuscular transmission in partially denervated mouse muscle.

The response of the neuromuscular junction to expansion of the motor unit after partial denervation (section of L5 root) was compared in soleus muscles from young (5-8 month) and old (25-30 month) mice. The object was to determine the relative capacity of young and old motor neurons to adapt to an enlarged functional field of innervation, and to delineate physiological parameters that are compromised under these conditions. Neuromuscular function was studied at 30, 60, and 120 d after partial denervation. The initial (18-23) and postoperative number (5-8) of motor units was the same in both age groups. Twitch strength declined in proportion to loss of motor units at 30 d but returned completely (young) or nearly completely (old) by 60 d. In old but not young muscle, the safety factor (assayed by twitch depression in low calcium) was decreased even before functional sprouting had occurred, indicating a reduced safety factor in nondenervated junctions. The proportion of fibers with "long" latencies (delay between stimulation and endplate potential) increased transiently (at 30 d) in young muscle but persisted without recovery at 120 d in regenerated junctions in old muscle. After partial denervation, decline in miniature endplate potential (mepp) amplitude, in mepp frequency, and in estimated quantal content of evoked release was relatively more pronounced in old than in young mice, and in the case of mepp amplitude and frequency, more persistent. Mepp amplitude was also decreased in presumed nondenervated junctions of old muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Age differences in morphology of reinnervation of partially denervated mouse muscle.

The effect of age on the ability of motor neurons to develop and maintain an enlarged total axonal and synaptic volume was compared in soleus muscles of 5-8-month and 25-30-month mice, 30-120 d after partial denervation. Before and after partial denervation (transection of the L5 root), the total number of muscle fibers was the same in all muscles. However, in young animals, there was only some transient atrophy and hypertrophy mostly receded by 120 d, whereas in old muscle, a more prominent early atrophy was followed by persistent hypertrophy. Ectopic endplates were not found. In zinc-iodide-osmium (ZIO) stained preparations, muscle fibers with small nerve terminals were present at 60 d and were still present in old muscle at 120 d. Fluorescent staining of nerve terminals and acetylcholine receptors revealed that in young muscle, postsynaptic sites were nearly or completely reoccupied by 60 d. In old muscle, about 22% of former junctions were denervated, with the remainder minimally to fully reinnervated. At 60 d and thereafter, collateral sprouts originated from nodes of Ranvier in both young and old muscle and were remyelinated in young but mainly unmyelinated and remarkably tortuous in old animals. These results, confirmed with immunofluorescent strains for myelin basic protein and neurofilaments, account for many of the physiological findings (Jacob and Robbins, 1990). Motor unit size expanded 2.5 times in young and 2 times in old muscle at 60 d after partial denervation. However, the increment in total quantal output and nerve terminal volume per motor neuron was 60-100% greater than control in young but only 20-25% greater in old muscle, with little further recovery. This inability of the motor neuron in old mice to expand the field of innervation may reflect a limitation imposed by reduced axonal transport. The present findings may elucidate the muscle weakness in postpolio syndrome and amyotrophic lateral sclerosis.

Motor nerve terminal restoration after focal destruction in young and old mice.

Regeneration of soleus motor nerve terminals after focal destruction by black widow spider venom (BWSV) or its active factor alpha-latrotoxin (LTx) was compared in young and old CBF-1 mice. The object was to determine whether previously reported delayed regeneration after nerve injury in old rodents was due to altered removal of debris, or delay or aberrancy in structural or functional restoration of the neuromuscular junction. In addition, the use of a new fluorescent technique permitted for the first time quantitation of the accuracy of early nerve terminal regeneration in mammalian muscle. Immunohistochemical and electron micrographic studies showed no age difference in destruction of terminals and removal of debris 2 days after toxin application. The indirect twitch and structural reinnervation (measured with flourescent techniques) returned to an equal extent in young and old mice beginning at 3 days after LTx treatment. BWSV (as opposed to LTx) delayed regeneration 1 day in young but not in old mice. On the first day of reinnervation, there was perisynaptic outgrowth in both young and old mice, although in the latter, there was a higher incidence of aberrant outgrowth. The relation between return of twitch strength and recovery of nerve terminal area (measured in teased zinc iodide-stained preparations) showed no age dependency. We conclude that factors cited to explain altered reactive sprouting in the aging CNS do not apply to regeneration of peripheral motor nerve terminals. However, it is possible that the aberrant regrowth observed at the neuromuscular junction in old mice will pertain to the aging CNS. Altered axonal rather than nerve terminal regeneration is the likely source of delayed peripheral nerve regeneration in old animals.

Hand protection and protection from hands: hand-washing, germicides and gloves.

A variety of soaps, detergents, germicides, and protective gloves are available for use by health care workers. Appropriate hand-washing and glove use will reduce the possibility of spread of infectious organisms from patient to staff, from patient to patient, and from staff to patient. Both hand-washing and glove use can have adverse effects. Excessive hand-washing, mechanical irritation from scrubbing, use of germicides, and wearing of gloves can result in irritant and allergic dermatitis. Dermatitis will result in an increased risk of infection to both the worker and the patient.