Diagnosis of myiasis by fine needle aspiration cytology: a case report

BACKGROUND: Myiasis is the infestation of tissues and organs by dipteran larvae and is endemic in tropical areas. Diagnosis usually is made by demonstration of a larva or larvae in infected tissue, generally recognizable to the naked eye. In our case, diagnosis was based on fine needle aspiration cytology (FNAC). CASE: A 59-year-old female patient with a painful neck mass was examined at an otorhinolaryngologic department after symptoms for several weeks. The lesion was found to be an absceding lymphadenitis, based on clinical symptoms, palpation and imaging (ultrasound and computed tomography). The lesion did not improve with repeated courses of antibiotics, so surgery was performed. Pus cultures collected after incision were negative, leaving origin of the inflammation undetermined. Smears from FNA of the residual mass demonstrated a worm-like pathogen alien to most European pathologists' experience. The pathogen was identified as a dipteran larva, leading to accurate etiologic diagnosis of myiasis. More scrupulous examination of the patient's history revealed she had spent her vacation in Australia, where she probably acquired the infection. CONCLUSION: Our case demonstrates the growing importance of the pathology of infectious diseases. One reason for this may be the ever-increasing possibility, frequency and distance of travel.     

The Medicago truncatula ortholog of Arabidopsis EIN2, sickle, is a negative regulator of symbiotic and pathogenic microbial associations

The plant hormone ethylene negatively regulates bacterial infection and nodule formation in legumes in response to symbiotic rhizobia, but the molecular mechanism(s) of ethylene action in symbiosis remain obscure. We have identified and characterized multiple mutant alleles of the MtSkl1 gene, which controls both ethylene sensitivity and nodule numbers. We show that this locus encodes the Medicago truncatula ortholog of the Arabidopsis ethylene signaling protein EIN2. In addition to the well-characterized role of MtSkl1 in rhizobial symbiosis, we show that MtSkl1 is involved in regulating early phases of the symbiotic interaction with mycorrhizal fungi, and in mediating root responses to cytokinin. MtSkl1 also functions in the defense against Rhizoctonia solani and Phytophthora medicaginis , with the latter interaction likely to involve positive feedback amplification of ethylene biosynthesis. Overexpression of the C-terminal domain of MtEIN2 is sufficient to block nodulation responses, consistent with previous reports in Arabidopsis on the activation of ethylene signaling. This same C-terminal region is uniquely conserved throughout the EIN2 homologs of angiosperms, which is consistent with its role as a higher plant-specific innovation essential to EIN2 function.     

Design and synthesis of peptide inhibitors of blood coagulations

Inhibition of blood coagulation by peptide aldehydes has been studied. Amino acid sequences were assembled from the P1-P2 portion of the cleavage sites(s) of clotting factors and residues selected experimentally. The thrombin-fibrinogen reaction could effectively be inhibited by D-Phe-Pro-Arg-H (GYKI-14,166) and Boc-D-Phe-Pro-Arg-H (GYKI-14,451). Plasmin digestion of fibrin could be retarded by Boc-Gln-Phe-Lys-H (GYKI-14,605) derived from a susceptible fragment, i.e. Asn-Phe-Lys decreases to Ser. However, such peptides could not retard the zymogen activations proceeding in Ca++ complexes (which seemed to be uneffected by heparin-antithrombin III, too). Inhibition of enzymes by peptide aldehydes showed marked substrate dependence.     

Restoration Ecology: Two-Sex Dynamics and Cost Minimization

We model a spatially detailed, two-sex population dynamics, to study the cost of ecological restoration. We assume that cost is proportional to the number of individuals introduced into a large habitat. We treat dispersal as homogeneous diffusion in a one-dimensional reaction-diffusion system. The local population dynamics depends on sex ratio at birth, and allows mortality rates to differ between sexes. Furthermore, local density dependence induces a strong Allee effect, implying that the initial population must be sufficiently large to avert rapid extinction. We address three different initial spatial distributions for the introduced individuals; for each we minimize the associated cost, constrained by the requirement that the species must be restored throughout the habitat. First, we consider spatially inhomogeneous, unstable stationary solutions of the model’s equations as plausible candidates for small restoration cost. Second, we use numerical simulations to find the smallest rectangular cluster, enclosing a spatially homogeneous population density, that minimizes the cost of assured restoration. Finally, by employing simulated annealing, we minimize restoration cost among all possible initial spatial distributions of females and males. For biased sex ratios, or for a significant between-sex difference in mortality, we find that sex-specific spatial distributions minimize the cost. But as long as the sex ratio maximizes the local equilibrium density for given mortality rates, a common homogeneous distribution for both sexes that spans a critical distance yields a similarly low cost.     

New sub-family of lysozyme-like proteins shows no catalytic activity: crystallographic and biochemical study of STM3605 protein from Salmonella Typhimurium

Phage viruses that infect prokaryotes integrate their genome into the host chromosome; thus, microbial genomes typically contain genetic remnants of both recent and ancient phage infections. Often phage genes occur in clusters of atypical G+C content that reflect integration of the foreign DNA. However, some phage genes occur in isolation without other phage gene neighbors, probably resulting from horizontal gene transfer. In these cases, the phage gene product is unlikely to function as a component of a mature phage particle, and instead may have been co-opted by the host for its own benefit. The product of one such gene from Salmonella enterica serovar Typhimurium, STM3605, encodes a protein with modest sequence similarity to phage-like lysozyme (N-acetylmuramidase) but appears to lack essential catalytic residues that are strictly conserved in all lysozymes. Close homologs in other bacteria share this characteristic. The structure of the STM3605 protein was characterized by X-ray crystallography, and functional assays showed that it is a stable, folded protein whose structure closely resembles lysozyme. However, this protein is unlikely to hydrolyze peptidoglycan. Instead, STM3605 is presumed to have evolved an alternative function because it shows some lytic activity and partitions to micelles.     

Voltage-gated sodium channel Nav1.7 maintains the membrane potential and regulates the activation and chemokine-induced migration of a monocyte-derived dendritic cell subset

Expression of CD1a protein defines a human dendritic cell (DC) subset with unique functional activities. We aimed to study the expression of the Nav1.7 sodium channel and the functional consequences of its activity in CD1a(-) and CD1a(+) DC. Single-cell electrophysiology (patch-clamp) and quantitative PCR experiments performed on sorted CD1a(-) and CD1a(+) immature DC (IDC) showed that the frequency of cells expressing Na(+) current, current density, and the relative expression of the SCN9A gene encoding Nav1.7 were significantly higher in CD1a(+) cells than in their CD1a(-) counterparts. The activity of Nav1.7 results in a depolarized resting membrane potential (-8.7 ± 1.5 mV) in CD1a(+) IDC as compared with CD1a(-) cells lacking Nav1.7 (-47 ± 6.2 mV). Stimulation of DC by inflammatory signals or by increased intracellular Ca(2+) levels resulted in reduced Nav1.7 expression. Silencing of the SCN9A gene shifted the membrane potential to a hyperpolarizing direction in CD1a(+) IDC, resulting in decreased cell migration, whereas pharmacological inhibition of Nav1.7 by tetrodotoxin sensitized the cells for activation signals. Fine-tuning of IDC functions by a voltage-gated sodium channel emerges as a new regulatory mechanism modulating the migration and cytokine responses of these DC subsets.     

Hawthorne Effect with Transient Behavioral and Biochemical Changes in a Randomized Controlled Sleep Extension Trial of Chronically Short-Sleeping Obese Adults: Implications for the Design and Interpretation of Clinical Studies

Objective

To evaluate the effects of study participation per se at the beginning of a sleep extension trial between screening, randomization, and the run-in visit.

Design

Subjects were screened, returned for randomization (Comparison vs. Intervention) after 81 days (median), and attended run-in visit 121 days later.

Setting

Outpatient.

Patients

Obese (N = 125; M/F, 30/95; Blacks/Whites/Other, N = 73/44/8), mean weight 107.6±19.7 kg, <6.5 h sleep/night.

Intervention

Non-pharmacological sleep extension.

Measurements

Sleep duration (diaries and actigraphy watch), sleep quality (Pittsburgh Sleep Quality Index), daily sleepiness (Epworth Sleepiness Scale), fasting glucose, insulin and lipids.

Results

Prior to any intervention, marked improvements occurred between screening and randomization. Sleep duration increased (diaries: 357.4 ±51.2 vs. 388.1±48.6 min/night; mean±SD; P<0.001 screening vs. randomization; actigraphy: 344.3 ±41.9 vs. 358.6±48.2 min/night; P<0.001) sleep quality improved (9.1±3.2 vs. 8.2±3.0 PSQI score; P<0.001), sleepiness tended to improve (8.9±4.6 vs. 8.3±4.5 ESS score; P = 0.06), insulin resistance decreased (0.327±0.038 vs. 0.351±0.045; Quicki index; P<0.001), and lipids improved, except for HDL-C. Abnormal fasting glucose (25% vs. 11%; P = 0.007), and metabolic syndrome (42% vs. 29%; P = 0.007) both decreased. In absence of intervention, the earlier metabolic improvements disappeared at the run-in visit.

Limitations

Relatively small sample size.

Conclusions

Improvements in biochemical and behavioral parameters between screening and randomization changed the “true” study baseline, thereby potentially affecting outcome. While regression to the mean and placebo effect were considered, these findings are most consistent with the “Hawthorne effect”, according to which behavior measured in the setting of an experimental study changes in response to the attention received from study investigators. This is the first time that biochemical changes were documented with respect to the Hawthorne effect. The findings have implications for the design and conduct of clinical research.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00261898","term_id":"NCT00261898"}}NCT00261898.     

Chemically induced carcinogenesis affecting chromatin structure in rat hepatocarcinoma cells

A new, chemically induced animal tumor cell line (HeDe) was established and characterized by its property of causing aggressively growing tumors in specific strain of rats and changes in the chromatin structure. Results show that (1) the nuclear material in nuclei of normal resting (G0) hepatocytes consists mainly of decondensed veil-like chromatin, chromosomes being clustered in six lobular domains; (2) nuclei of HeDe cells contain primarily supercoiled chromatin; or (3) the nuclear material of tumor cells undergoes apoptosis seen as apoptotic bodies. Heterogeneity of chromatin structures was expressed as contour/area ratio and was nine times higher in apoptotic cells and two times higher in tumor cells compared to resting cells.     

Cell culture density dependent toxicity and chromatin changes upon cadmium treatment in murine pre-B-cells

Murine pre-B-cells grown in the presence of lower (1 μM) or higher (5 μM) concentration of cadmium chloride were separated into 13 fractions by centrifugal elutriation. The rate of DNA synthesis after cadmium treatment determined in permeable cells was dependent on cell culture density during cadmium treatment. Cell cycle analysis revealed a shift in the profile of DNA synthesis from replicative to repair DNA synthesis upon cadmium treatment. The study of the relationship between cell culture density and cell diameter at lower and higher cell densities in the presence of 1 μM cadmium chloride concentration showed that a. at 5×10⁵ cell/ml or lower densities cells were shrinking indicating apoptotic changes, b. at higher cell culture densities the average cell size increased, c. the treatment of cells with low CdCl₂ concentration (1 μM) at higher cell culture density (>5×10⁵ cell/ml) did not change significantly the average cell diameter. At 5 μM cadmium concentration and higher cell culture densities (>5×10⁵ cell/ml) the average cell size decreased in each elutriated fraction. Most significant inhibition of cell growth took place in early S phase (2.0–2.5 C value). Apoptotic chromatin changes in chromatin structure after cadmium treatment were seen as large extensive disruptions, holes in the nuclear membrane and stickiness of incompletely folded chromosomes.     

Nitric oxide mediates T cell cytokine production and signal transduction in histidine decarboxylase knockout mice

Histamine is a key regulator of the immune system. Several lines of evidence suggest the role of histamine in T cell activation and accelerated Th1 immune response is a hallmark of histidine decarboxylase knockout (HDC-KO) mice, with a complete lack of endogenously produced histamine. According to our previous work, T lymphocytes produce NO upon activation, and NO is necessary for effective T cell activation. To study the role of histamine in T cell activation, we investigated cytokine production and T cell signal transduction in HDC-KO and wild-type (WT) mice. In the absence of histamine, an elevated IFN-gamma mRNA and protein levels of splenocytes (p < 0.001; p = 0.001, respectively) were associated with a markedly increased (2.5-fold, p = 0.0009) NO production, compared with WT animals. Furthermore, histamine treatment decreased the NO production of splenocytes from both WT and HDC-KO mice (p = 0.001; p = 0.0004, respectively). NO precursor (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl) amino] diazen-1-ium-1,2-diolate-diethylenetriamine elicited IFN-gamma production (p = 0.0002), whereas NO synthase inhibitors N(G)-monomethyl-L-arginine and nitronidazole both inhibited IFN-gamma production (p = 0.002 and p = 0.01, respectively), suggesting the role of NO in regulating IFN-gamma synthesis. Cytoplasmic Ca(2+) concentration of unstimulated T cells was increased in the HDC-KO mice (p = 0.02), whereas T cell activation-induced delta Ca(2+)-signal was similar in both HDC-KO and WT animals. Our present data indicate that, in addition to its direct effects on T lymphocyte function, histamine regulates cytokine production and T cell signal transduction through regulating NO production.