All measured tests are good at predicting the presence of disease on final pathology, but none are able to reliably predict a pathologic complete response.

Tuberculosis patients may harbor both drug-susceptible and -resistant bacteria, i.e., heteroresistance. We used mixtures of rifampin-resistant and -susceptible Mycobacterium tuberculosis strains to simulate heteroresistance in patient samples. Molecular tests can be used for earlier discovery of multidrug resistance (MDR), but the sensitivity to detect heteroresistance is unknown. Conventional phenotypic drug susceptibility testing was the most sensitive, whereas two line probe assays and sequencing were unable to detect the clinically important 1% resistant bacteria. Patients with tuberculosis (TB) that harbor drug-susceptible Mycobacterium tuberculosis strains may also have a small proportion of drug-resistant bacteria that develops spontaneously during replication, normally at a rate of 10 Ϫ8 to 10 Ϫ9 mutations/ cell division (1). For rifampin (Rif) resistance, mutations are almost exclusively found in a single gene, rpoB (2). Conventional drug susceptibility testing (DST) aims to determine if 1% or more of the bacterial population in clinical specimens is drug resistant (3, 4). In this study, cultures that contain both susceptible and at least 1% resistant bacteria are defined as heteroresistant. Heteroresistance is thought to be an early stage in the development of drug-resistant TB in a patient. In such cases, failing to detect resistance may lead to insufficient treatment and treatment failure. As a consequence, spread of resistant bacteria may occur in the future (5). The prevalence of heteroresistance is unknown and is presumably dependent on the local resistance epidemiology. Findings of heteroresistance are accidental, and simple methods for the detection are needed (6).In recent years, a number of genotypic methods have become available for rapid detection of mutations that may confer resistance. Molecular tests have been recommended for use worldwide, with the objective of earlier discovery of multidrug resistance (MDR) (http://www.who.int/tb/features_archive/policy _statement.pdf). These assays are important for the global scaling up of detection of MDR-TB. However, little is known of the sensitivity of these methods to detect resistance in heteroresistant specimens. The aim of the present study was to evaluate the ability of different DST methods to detect Rif resistance when heteroresistance is present.Two freeze-dried strains each of the spoligo families Haarlem and Beijing were obtained from the WHO Tropical Disease Research (TDR) TB Strain Bank. The Haarlem strain TB-TDR-063 was susceptible, and TB-TDR-165 was Rif resistant with the rpoB H526Y mutation. The Beijing strain TB-TDR-077 was susceptible, and TB-TDR-068 was Rif resistant with the rpoB S531L mutation. The susceptible strains from both families had wild-type (WT) DNA in rpoB. The strains were subcultured in Dubos with 0.045% Tween 80 (SSI Diagnostika, Hilleroed, Denmark) with 1 mg/ml Rif (BD, Franklin Lakes, NJ) diluted in water for the resistant strains. After 2 weeks of incubation at 37°C, the bacterial concentrations in liquid medi...

It is now accepted that neurons contain and release multiple transmitter substances. However, we still have only limited insight into the regulation and functional effects of this co-transmission. Given that there are 200 or more neurotransmitters, the chemical complexity of the nervous system is daunting. This is made more-so by the fact that their interacting effects can generate diverse non-linear and novel consequences. The relatively poor history of pharmacological approaches likely reflects the fact that manipulating a transmitter system will not necessarily mimic its roles within the normal chemical environment of the nervous system (e.g., when it acts in parallel with co-transmitters). In this article, co-transmission is discussed in a range of systems [from invertebrate and lower vertebrate models, up to the mammalian peripheral and central nervous system (CNS)] to highlight approaches used, degree of understanding, and open questions and future directions. Finally, we offer some outlines of what we consider to be the general principles of co-transmission, as well as what we think are the most pressing general aspects that need to be addressed to move forward in our understanding of co-transmission.

A prospective observational nationwide investigation was performed from September 2005 to August 2006 to study the epidemiology of candidaemia in Sweden. From 385 patients, 403 isolates were recovered, yielding an incidence of 4.2 cases per 100 000 inhabitants. Candida albicans was the most common species (61%), followed by Candida glabrata (20%) and Candida parapsilosis (9%). The rates of resistance to fluconazole were ≤ 1% in C. albicans and 6-29% in non-albicans species other than C. glabrata and Candida krusei. Resistance to voriconazole was rare, except for C. glabrata and C. krusei. Only three isolates had reduced susceptibility to amphotericin B, and one had reduced susceptibility to caspofungin.

Mycobacterium chimaera was present at high rates (>80%) in heater–cooler units (HCUs) from all 5 thoracic surgery departments in Denmark. Isolates were clonal to HCU-associated isolates from the United States (including some from patients) and United Kingdom. However, M. chimaera from 2 brands of HCU were genetically distinct.

Abstract. Contact freezing of single supercooled water droplets colliding with kaolinite dust particles has been investigated. The experiments were performed with droplets levitated in an electrodynamic balance at temperatures from 240 to 268 K. Under relatively dry conditions (when no water vapor was added) freezing was observed to occur below 249 K, while a freezing threshold of 267 K was observed when water vapor was added to the air in the chamber.The effect of relative humidity is attributed to an influence on the contact freezing process for the kaolinite-water droplet system, and it is not related to the lifetime of the droplets in the electrodynamic balance. Freezing probabilities per collision were derived assuming that collisions at the lowest temperature employed had a probability of unity. Mechanisms for contact freezing are briefly discussed.

No abstract

Spinal locomotor networks in the lamprey are modulated by tachykinin neuropeptides. A single 10 min application of the tachykinin substance P evokes a short-term (ϳ1 hr) presynaptic facilitation of glutamate release and the postsynaptic potentiation of NMDA responses. The latter effect induces a long-term (Ͼ24 hr) protein synthesis-dependent increase in the frequency of network activity. Tachykinins are contained in a ventromedial spinal plexus into which the medial dendrites of network neurons project. Neurons in this plexus also contain colocalized dopamine and 5-HT. Here, dynamic plasticity evoked by modulator interactions has been examined by investigating the effects of 5-HT and dopamine on specific cellular, synaptic, and network effects of substance P.Preapplied 5-HT blocked the substance P-mediated increase in the network burst frequency and the potentiation of NMDAevoked cellular responses that underlies its induction. 5-HT also blocked the presynaptic facilitation of glutamatergic synaptic transmission by substance P. The presynaptic, but not postsynaptic, effect of 5-HT was reduced by the protein phosphatase 2B inhibitor cypermethrin.Dopamine did not directly modulate the effects of substance P. However, it reduced the presynaptic interactive effect of 5-HT and thus gated the presynaptic potentiation of glutamatergic inputs by substance P. However, the substance P-mediated potentiation of NMDA responses was not gated by dopamine, and thus the long-term network modulation was not induced.Neuromodulator effects and their interactions can thus be modulated. By selecting components from the modulatory repertoire of substance P, these interactions evoke dynamic changes in short-and long-term synaptic and network plasticity.