Appropriateness of use of indwelling urinary catheters in patients admitted to the medical service.

Of 836 medical admissions evaluated over a 1-month period, 89 (10.7%) had a urinary catheter placed within 24 hours; 34 placements (38%) had no justifiable indication. Risk for inappropriate catheterization was independent of age, gender, functional status, and mental status at admission. Preventive measures should focus on increasing awareness among healthcare providers.     

Factors influencing women’s decision making in hysterectomy

Objective

To explore factors influencing how well-informed women felt about hysterectomy, influences on their decision making, and on them receiving a less-invasive alternative to open surgery.

Issue Information

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency disease, and its prevalence varies significantly among different population. Minority of CVID patients present a familial aggregation suggesting a higher probability of heritable genetic defects. A total of 235 registered CVID patients were evaluated in this cohort study. Familial and sporadic patients were stratified, and demographic information, clinical records, laboratory and molecular data were compared among these two groups of patients. Multiple cases were identified in 12 families (30 patients) and sporadic presentation in 120 cases. The rate of parental consanguinity (83.3%) and clinical presentation of lymphoid malignancy (20.7%) were predominant in familial CVID patients, whereas significantly increased recurrent upper respiratory infections were recorded in sporadic patients (0.3 infections per year). Probands of familial group were presented with a higher severity score resulting in a profound mortality rate (41.7% after 30‐year follow‐up) comparing to the non‐proband CVID patients in the same families with a lowered diagnostic delay. Familial CVID patients had a specific signature in clinical presentation and immunologic profile, and a high consanguinity in this group of patients suggests a Mendelian trait with an autosomal recessive inheritance pattern. Diagnosis of an index patient within a multiple case families significantly improves the diagnostic process and outcomes of the yet asymptomatic patients.     

Announcement

Selective immunoglobulin A deficiency (SIgAD) is the most common primary antibody deficiency. Although more patients with SIgAD are asymptomatic, selected patients suffer from different clinical complications such as pulmonary infections, allergies, autoimmune diseases, gastrointestinal disorders and malignancy. Pathogenesis of SIgAD is still unknown; however, a defective terminal differentiation of B cells and defect in switching to IgA‐producing plasma cells are presumed to be responsible. Furthermore, some cytogenic defects and monogenic mutations are associated with SIgAD. There is no specific treatment for patients with symptomatic IgA deficiency, although prophylactic antibiotic therapy along with circumstantial immunoglobulin replacement with justification and supportive care (using a product that contains minimal IgA) could be helpful for patients with a severe phenotype. The epidemiology, pathogenesis, clinical phenotype, diagnosis, prognosis, management and treatment in patients with SIgAD have been reviewed.     

Interleukin-4 Modulation of Platelet-Derived Growth Factor–Induced Smooth Muscle Cell Urokinase Plasminogen Activator

Platelet-derived growth factor (PDGF) stimulates smooth muscle cell (SMC) migration owing to stimulation of SMC tissue plasminogen activator (t-PA) production. In this study we examined the effects of the T-cell lymphokine interleukin-4 (IL-4) on PDGF induction of human aortic SMC antigen levels of urokinase-type plasminogen activator (u-PA) and those of plasminogen activator inhibitor-1 (PAI-1), the endogenous inhibitor of t-PA and u-PA, measured by enzyme-linked immunosorbent assays (ELISAs). u-PA antigen levels from human aortic SMC incubated with PDGF 100 ng/mL and IL-4 500 U/mL were significantly greater than those incubated with PDGF 100 ng/mL alone. Coincubation of PDGF with IL-4 did not significantly increase SMC u-PA antigen levels in cellular lysates. Coincubation with PDGF 100 ng/mL and IL-4 500 U/mL did not significantly affect SMC PAI-1 antigen levels in conditioned media or cellular lysates. Therefore, interleukin-4 modulates vascular SMC u-PA production induced by PDGF.     

From the Cover: Administration of thimerosal-containing vaccines to infant rhesus macaques does not result in autism-like behavior or neuropathology

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder. Some anecdotal reports suggest that ASD is related to exposure to ethyl mercury, in the form of the vaccine preservative, thimerosal, and/or receiving the measles, mumps, rubella (MMR) vaccine. Using infant rhesus macaques receiving thimerosal-containing vaccines (TCVs) following the recommended pediatric vaccine schedules from the 1990s and 2008, we examined behavior, and neuropathology in three brain regions found to exhibit neuropathology in postmortem ASD brains. No neuronal cellular or protein changes in the cerebellum, hippocampus, or amygdala were observed in animals following the 1990s or 2008 vaccine schedules. Analysis of social behavior in juvenile animals indicated that there were no significant differences in negative behaviors between animals in the control and experimental groups. These data indicate that administration of TCVs and/or the MMR vaccine to rhesus macaques does not result in neuropathological abnormalities, or aberrant behaviors, like those observed in ASD.Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder presenting in early childhood with a current prevalence ranging from 0.7% to 2.64% in the United States (1). ASD is defined by the presence of marked social deficits, specific language abnormalities, and stereotyped repetitive patterns of behavior (2). Genetic and environmental factors have been found to play a role in the disorder (3, 4). The neuropathology of autism is now beginning to be understood; however, there is still much to be learned. Thus far, the major neuropathological changes observed in autism are changes in neuronal size in the limbic system; decreased numbers of Purkinje cells in the cerebellum; abnormalities in the brainstem, neocortex, amygdala, and hippocampus; features of cortical dysgenesis or migration disturbances; and alterations in GABAergic and cholinergic systems [see Gadad et al. (3) and Amaral (5) for reviews]. In many autism studies, comorbid conditions such as seizure disorders or intellectual disabilities contribute to the heterogeneity of the neuropathology.An association between exposure to thimerosal-containing vaccines (TCVs) and developmental abnormalities has been debated since 1999 when the US Food and Drug Administration determined that children receiving multiple TCVs at a young age were at risk for exceeding the Environmental Protection Agency’s safe exposure limits for methylmercury (MeHg). Results from an Institute of Medicine (IOM) review on the safety of childhood vaccines found that there was not sufficient evidence to render an opinion on the relationship between exposure to TCVs or the measles, mumps, rubella (MMR) vaccine and developmental disorders in children (IOM 2001) (6). The IOM review did, however, note the possibility of such a relationship and recommended further studies be conducted. A more recent second review of TCVs and autism (IOM 2004) (7) came to the same conclusion reached earlier: that there was no epidemiological data to support a relationship between TCVs and childhood developmental disorders. Several epidemiological studies sought to determine whether TCVs resulted in neurodevelopmental disorders including autism; however, both nonsignificant and significant associations have been reported (8–12). Significant associations have been reported by Thompson et al. (11), who investigated the association between TCVs and immune globulins early in life and neuropsychological outcomes in children at 7–10 y of age. The data included the evaluation of 1,047 children and their biological mothers and 24 neuropsychological tests. The only variable that was statistically significant was tics; children who were exposed to higher doses of thimerosal were more likely to exhibit tics. In a follow-up study by Barile et al. (12) examining a subset of the data from Thompson et al. (11), they found a significant association between thimerosal dosage and tics, but only in boys. They found no statistically significant associations between thimerosal exposure from vaccines early in life and six of the seven neuropsychological constructs examined.Concern regarding the safety of childhood vaccines has had a major impact on immunization rates (13–16). It is of great importance to determine whether TCVs play a significant role in altering brain development and/or behaviors that mimic changes observed in autism. The present study provides a comprehensive analysis of the influence of TCVs on the brain and behavior in a nonhuman primate model. The study includes 79 rhesus macaques in six groups (n = 12–16 per group): (i) Control, a control group given saline injections; (ii) 1990s Pediatric, replicating the pediatric vaccination schedule used for infants in the 1990s that included several TCVs; (iii) 1990s Primate, replicating the pediatric vaccination schedule used in the 1990s but accelerated fourfold representing the faster development of infant macaques; (iv) TCVs, only TCVs and no MMR; (v) MMR, only the MMR vaccine; and (vi) 2008, the expanded pediatric schedule used in 2008 (and very similar to that used today, which also includes a prenatal influenza vaccine; 17).

Table 1.

Vaccination schedules used for the six groups of animals

Polytypism,polymorphism, and superconductivity in TaSe2?xTex

Polymorphism in materials often leads to significantly different physical properties—the rutile and anatase polymorphs of TiO₂ are a prime example. Polytypism is a special type of polymorphism, occurring in layered materials when the geometry of a repeating structural layer is maintained but the layer-stacking sequence of the overall crystal structure can be varied; SiC is an example of a material with many polytypes. Although polymorphs can have radically different physical properties, it is much rarer for polytypism to impact physical properties in a dramatic fashion. Here we study the effects of polytypism and polymorphism on the superconductivity of TaSe₂, one of the archetypal members of the large family of layered dichalcogenides. We show that it is possible to access two stable polytypes and two stable polymorphs in the TaSe_2−xTe_x solid solution and find that the 3R polytype shows a superconducting transition temperature that is between 6 and 17 times higher than that of the much more commonly found 2H polytype. The reason for this dramatic change is not apparent, but we propose that it arises either from a remarkable dependence of T_c on subtle differences in the characteristics of the single layers present or from a surprising effect of the layer-stacking sequence on electronic properties that are typically expected to be dominated by the properties of a single layer in materials of this kind.The MX₂ layered transition-metal dichalcogenides (TMDCs, M = Mo, W, V, Nb, Ta, Ti, Zr, Hf, or Re and X = Se, S, or Te), have long been of interest due to the rich electronic properties that emerge due to their low dimensionality (1–9). Structurally, these compounds can be regarded as having strongly bonded (2D) X–M–X layers, with M in either trigonal prismatic or octahedral coordination with X, and weak interlayer X–X bonding of the van der Waals type. Many of these materials manifest charge-density waves and competition between charge-density waves (CDWs) and superconductivity, e.g., refs. 5–9. Among the TMDCs, the 2H (H: hexagonal) polytype of tantalum diselenide (2H-TaSe₂) is considered one of the foundational materials (8–18), showing a transition from a metallic phase to an incommensurate charge-density wave (ICDW) phase at 123 K, followed by a “lock-in” transition to a commensurate charge-density wave (CCDW) phase at 90 K. It finally becomes a superconductor with a rather low transition temperature (T_c) of 0.15 K. Although detailed studies have been performed on the physics of CDWs and superconductivity in 2H-TaSe₂ (16–18), a comparative study of the superconductivity of the polytypes and polymorphs of TaSe₂ from the chemical perspective has not been done.TaSe₂ is highly polymorphic, possibly the most polymorphic of the TMDCs (19). In some of its forms, notably the 2H and 3R (R: rhombohedral) polytypes (Fig. 1A), Ta is found in trigonal prismatic coordination in Se-Ta-Se layers that are stacked along the c axis of the hexagonal (or rhombohedral) cell. The 2H and 3R polytypes differ only in their stacking periodicity—the structure repeats after two layers in the 2H form and three layers in the 3R form (20–22). The 3R form can be synthesized, but it is not the stable variant (the 2H form is) and so has been the subject of little study. In one of the other polymorphs, the 1T (T: trigonal) type, Ta is found in octahedral coordination in the Se-Ta-Se layers and the layer stacking along the c axis of the trigonal cell such that the structure repeats after only one layer (23) (Fig. 1A). Again, the 1T form has not been the subject of much study. Here we show that the 3R and 1T polymorphs are both quite stable in the TaSe_2−xTe_x system and that they are both superconducting. For pure TaTe₂, the monoclinic structure is 1T based (Fig. 1A), but is distorted such that there are two nonequivalent Ta and three nonequivalent Te positions in the unit cell (24); we find TaSe_2−xTe_x in this polymorph to be nonsuperconducting down to 0.4 K.Open in a separate windowFig. 1.Structural characterization and analysis of the polytypes and polymorphs of TaSe_2−xTe_x. (A) The crystal structures of 2H-TaSe₂, 3R-TaSe_1.65Te_0.35, 1T-TaSeTe, and monoclinic TaTe₂. (B) Powder X-ray diffraction pattern for 3R-TaSe_1.65Te_0.35. Inset shows the reduced lattice parameter ratio, (c/n)/a, where n = number of layers per cell, for 2H-TaSe₂ (38) and 3R-TaSe_2−xTe_x. (C) Powder X-ray diffraction pattern for 1T-TaTeSe. Inset shows the reduced lattice parameter ratio, (c/n)/a, for 1T-TaSe_2−xTe_x. (D) The variation of in-plane lattice parameter, a, with x for 2H-, 3R-, and 1T-TaSe_2−xTe_x. (E) The variation of reduced stacking-direction lattice parameter, c/n, with x for 2H-, 3R-, and 1T-TaSe_2−xTe_x. (F) The variation of the TaX₂ slab thickness, ((c·(∆z)), with x for 2H-, 3R-, and 1T-TaSe_2−xTe_x. (G) The variation of the van der Waals gap (vdWG) thickness with x for 2H-, 3R-, and 1T-TaSe_2−xTe_x.We report the structures and superconducting properties of TaSe_2−xTe_x for 0 ≤ x ≤ 2. The 2H, 3R, 1T, and monoclinic distorted 1T-structure forms were successfully synthesized. Only a small amount of Te doping (x = 0.02) changes 2H-TaSe₂ into the 3R polytype. Within the 3R polytype, TaSe_2−xTe_x shows the coexistence of a CDW and superconductivity above 0.4 K for 0.1 ≤ x ≤ 0.35. The Te-rich limit of the 3R-TaSe_1.65Te_0.35 polytype shows the highest T_c in the system, 2.4 K, which is 17 times higher than that of 2H-TaSe₂. For 0.8 ≤ x ≤ 1.3, 1T-type TaSe_2−xTe_x emerges and shows a lower T_c, of 0.5–0.7 K. At higher Te substitutions (1.8 ≤ x ≤ 2), TaSe_2−xTe_x changes again, into the monoclinic polymorph, and shows normal metallic behavior to 0.4 K. We argue that the isovalent Te/Se substitution acts to tune the anisotropy of the layers, inducing the 3R to 1T transition, consistent with what has been proposed previously (25). The driving force for the 2H to 3R transition currently remains obscure.