Evaluation of <Emphasis Type="Italic">Fusarium solani</Emphasis> Hyphae and Conidia Susceptibility to Amphotericin B and Itraconazole: Study of a Clinical Case

Fusarium species are hyaline moulds belonging to the hyalohyphomycosis group that are usually found in the soil and plants. This organism has emerged as a cause of disseminated invasive disease. The correlation between in vitro value and clinical efficacy is low and many patients remain unresponsive to treatment despite in vitro susceptibility. We determined growth control for Fusarium solani using the BioCell-Tracer system that measures the growth rate of a single fungal hypha, and the effect of different concentrations of amphotericin B and itraconazole. The MIC for these two drugs was also determined by a broth microdilution technique, using RPMI 1640. Different MICs for amphotericin B were obtained by the two different methods. This paper describes a case of infection due to Fusarium solani in an allogeneic bone marrow transplanted patient, the microbiological diagnostic, antifungal susceptibility tests for conidia and hypha and clinical correlation.     

Effects of neck and circumoesophageal connective lesions on posture and locomotion in the cockroach

Few studies in arthropods have documented to what extent local control centers in the thorax can support locomotion in absence of inputs from head ganglia. Posture, walking, and leg motor activity was examined in cockroaches with lesions of neck or circumoesophageal connectives. Early in recovery, cockroaches with neck lesions had hyper-extended postures and did not walk. After recovery, posture was less hyper-extended and animals initiated slow leg movements for multiple cycles. Neck lesioned individuals showed an increase in walking after injection of either octopamine or pilocarpine. The phase of leg movement between segments was reduced in neck lesioned cockroaches from that seen in intact animals, while phases in the same segment remained constant. Neither octopamine nor pilocarpine initiated changes in coordination between segments in neck lesioned individuals. Animals with lesions of the circumoesophageal connectives had postures similar to intact individuals but walked in a tripod gait for extended periods of time. Changes in activity of slow tibial extensor and coxal depressor motor neurons and concomitant changes in leg joint angles were present after the lesions. This suggests that thoracic circuits are sufficient to produce leg movements but coordinated walking with normal motor patterns requires descending input from head ganglia.Electronic Supplementary Material Supplementary material is available for this article at     

Baroreceptor reflex control of heart rate in rats studied by induced and autogenic changes in arterial pressure

The function of the arterial baroreflex has traditionally been assessed by measurement of reflex changes in heart rate (HR) or sympathetic nerve activity resulting from experimenter-induced manipulation of arterial blood pressure (the Oxford method, also termed the pharmacological method). However, logistical and flexibility limitations of this technique have promoted the development of new methods for assessing baroreflex function such as the evaluation of changes in spontaneous arterial pressure and HR. Although this new spontaneous method has been validated in dogs and humans, it has not been rigorously tested in rats. In the present study, the method of correlating spontaneous changes in systolic blood pressure and HR was evaluated in resting, normotensive Sprague-Dawley rats. This technique was found to be neither reliable nor valid under the conditions employed in the present protocol. We also tested a variation of the spontaneous method that evaluates particular sequences of data during which arterial pressure and pulse interval are changing in the same direction for at least three consecutive heartbeats (the sequence method). The sequence method did not provide extra reliability or validity over the spontaneous method. We conclude that due to the restricted range of variability obtained by measuring spontaneous blood pressure fluctuations, the spontaneous and sequence techniques do not provide data that are comparable to the traditional method of assessing HR changes triggered by arterial blood pressure increases and decreases induced by vasoactive drugs. However, it is possible that surgical stress obscured the relationship between blood pressure and HR, and therefore additional studies are needed to determine whether the spontaneous and sequence methods can be applied to rats during different behavioral states.     

Microbiological control in stem cell banks: approaches to standardisation

The transplant of cells of human origin is an increasingly complex sector of medicine which entails great opportunities for the treatment of a range of diseases. Stem cell banks should assure the quality, traceability and safety of cultures for transplantation and must implement an effective programme to prevent contamination of the final product. In donors, the presence of infectious micro-organisms, like human immunodeficiency virus, hepatitis B virus, hepatitis C virus and human T cell lymphotrophic virus, should be evaluated in addition to the possibility of other new infectious agents (e.g. transmissible spongiform encephalopathies and severe acute respiratory syndrome). The introduction of the nucleic acid amplification can avoid the window period of these viral infections. Contamination from the laboratory environment can be achieved by routine screening for bacteria, fungi, yeast and mycoplasma by European pharmacopoeia tests. Fastidious micro-organisms, and an adventitious or endogenous virus, is a well-known fact that will also have to be considered for processes involving in vitro culture of stem cells. It is also a standard part of current good practice in stem cell banks to carry out routine environmental microbiological monitoring of the cleanrooms where the cell cultures and their products are prepared. The risk of viral contamination from products of animal origin, like bovine serum and mouse fibroblasts as a “feeder layer” for the development of embryonic cell lines, should also be considered. Stem cell lines should be tested for prion particles and a virus of animal origin that assure an acceptable quality.     

HIV international clinical research: exploitation and risk

This paper aims to show that to reduce the level of exploitation present in (some) international clinical trials, research sponsors must aim to provide both an ex-ante expected gain in utility and a fair ex-post distribution of benefits for research subjects. I suggest the following principles of fair risk distribution in international research as the basis of a normative definition of fairness: (a) Persons should not be forced (by circumstance) to gamble in order to achieve or protect basic goods; (b) In cases where one party is gambling with basic goods and the other party is not, the distribution of benefits and burdens must be arranged so that they are of greatest benefit to the worst off; (c) In relationships where one party is gambling for basic goods and the other party is not, the party gambling for basic goods must be assured of some guaranteed benefits in addition to the chance of getting some practical benefits. These principles are applied to the case of HIV international research. I conclude that the research (as described) is mutually advantageous but still exploitative because the distribution of surplus benefits is unfair. It is unfair because research subjects are gambling with and for basic goods but they are not assured of a fair ex-post distribution of benefits. Principles (b) and (c) are not satisfied. Research participants are not accorded enough guaranteed benefits to outweigh the risks they undertake.     

<Emphasis Type="Italic">N</Emphasis>-methyl-<Emphasis Type="SmallCaps">D</Emphasis>-aspartate Receptors are Involved in the Quinolinic Acid,but not in the Malonate Pro-oxidative Activity <Emphasis Type="Italic">in vitro</Emphasis>

Oxidative stress plays a significant role in the neurotoxicity of a variety of agents that interact with the N-methyl-D-aspartate (NMDA) receptors. Here we investigated in a comparative way the pro-oxidative effects of quinolinic acid (QA) and malonate, two neurotoxic substances that act through distinct primary molecular mechanisms on the production of thiobarbituric acid reactive species (TBARS) by brain homogenates. In fact, QA is thought to activate directly the NMDA receptor, whereas malonate seems to act primarily by inhibiting oxidative metabolism. The malonate-induced TBARS formation was not modified by cyanide (CN^–) or 2,4-dinitrophenol. MK-801 did not reduce basal or malonate induced-TBARS production in fresh tissues preparations. However, in heat-treated preparations a significant effect of MK-801 against basal TBARS production was observed, but not on the malonate induced-TBARS production. QA induced-TBARS production was significantly prevented by MK-801 either in fresh or heat-treated preparations. The antioxidant effect of MK-801 on basal and QA-induced TBARS production increased as the temperatures used to treat S1 were increased. Succinate dehydrogenase (SDH) was inhibited by malonate but not by QA. Malonate was able to chelate iron(II) and the malonate-iron complex(es) is(are) active as measured by its(their) activity on deoxyribose degradation assay. These findings indicate that direct interactions of malonate with NMDA receptors are not involved in malonate pro-oxidative activity in vitro. QA pro-oxidative activity in vitro was related, at least in part, to its capability in stimulate NMDA receptors. Taken together, these findings indicated that malonate pro-oxidative activity in vitro could be attributed to its capability of changing the ratio Fe²⁺/ Fe³⁺, which is essential to TBARS production.     

Genotyping of Chromobacterium violaceum isolates by recA PCR-RFLP analysis

Intraspecies variation of Chromobacterium violaceum was examined by comparative sequence - and by restriction fragment length polymorphism analysis of the recombinase A gene (recA-PCR-RFLP). Primers deduced from the known recA gene sequence of the type strain C. violaceum ATCC 12472(T) allowed the specific amplification of a 1040bp recA fragment from each of the 13 C. violaceum strains investigated, whereas other closely related organisms tested negative. HindII-PstI-recA RFLP analysis generated from 13 representative C. violaceum strains enabled us to identify at least three different genospecies. In conclusion, analysis of the recA gene provides a rapid and robust nucleotide sequence-based approach to specifically identify and classify C. violaceum on genospecies level.     

The calcineurin inhibitor gossypol impairs growth, cell signalling and development in Dictyostelium discoideum

The Dictyostelium genome harbors single copy genes for both the catalytic and regulatory subunits of the Ca2+/calmodulin-dependent protein phosphatase calcineurin. Since molecular genetic approaches to reduce the expression of these genes have failed so far, we attempted to pharmacologically target calcineurin activity in vivo by using the recently described calcineurin inhibitor, gossypol. Up-regulation of expression of the gene for the Ca2+-ATPase PAT1 in conditions of Ca2+ stress was reduced by gossypol. Dictyostelium wild-type cells treated with 12.5-100 microM gossypol showed reduced growth rates and impaired development. In addition, cell signalling was affected. A cell line that overproduces the catalytic subunit of calcineurin was more resistant to gossypol.     

Reduced prevalence of Epstein-Barr virus-related lymphocryptovirus infection in sera from a new world primate

The recent discovery of an Epstein-Barr virus (EBV)-related lymphocryptovirus (LCV) naturally infecting common marmosets demonstrated that gamma-1 herpesviruses are not limited to human and Old World nonhuman primate hosts. We developed serologic assays to detect serum antibodies against lytic- and latent-infection marmoset LCV antigens in order to perform the first seroepidemiologic study of LCV infection in New World primates. In three different domestic colonies and in animals recently captured from the wild, we found that the seroprevalence of marmoset LCV infection was not as ubiquitous as with EBV or Old World LCV. These biologic differences in LCV infection of New World versus human and Old World primate hosts correlate with the evolution of the LCV viral gene repertoire.