Modulation of mechanosensory responses by motoneurons that regulate skin surface topology in the leech

Central regulation of somatosensory signals has been extensively studied, but little is known about their regulation in the periphery. Given the widespread exposure of the skin sensory terminals to the environment, it is of interest to explore how somatosensory sensitivity is affected by changes in properties of the skin. In the leech, the annuli that subdivide the skin can be erected under the control of the annulus erector (AE) motoneurons. To analyze whether this surface change influences mechanosensory sensitivity, we studied the responses of low threshold mechanosensory T cells to mechanical stimulation of the skin as AE motoneurons were activated. In segments of the body wall connected to the corresponding ganglion and submerged in an aqueous environment, T cells responded to localized bubbling on the skin and to water flow parallel to its surface. Excitation of AE motoneurons diminished these responses in a way that depended on the motoneuron firing frequency. Video recordings established that the range of AE firing frequencies that produced effective annulus erection coincided with that influencing T cell responses. In isolated ganglia, AE firing had no effect on T cell excitability, suggesting that annulus erection diminished T cell responsiveness to mechanical input. Counteracting this effect, mechanosensory inputs inhibited AE motoneurons. However, because depolarization of AE cells caused a decrease in their input resistance, the more active the motoneuron, the less sensitive it became to inhibitory signals. Thus when brought to fire, AE motoneurons would stay "committed" to a high activity level, and this would limit sensory responsiveness to incoming mechanical signals.     

The pattern of cardiovascular alterations induced by infusion of platelet-activating factor in rabbit is modified by pretreatment with H1-H2 receptor antagonists but not by cyclooxygenase inhibition

The intravenous infusion of platelet activating factor (PAF) (0.8 g/kg b.w.) induced ECG and hemodynamic alterations characterized by the following sequential three phases. Phase I (15 sec) consisted of a transient bradycardia with reduction in left ventricular pressure (LVPs), mean arterial pressure (MAP) and cardiac output (CO). Phase II developed within 30 sec and consisted of a rise in cardiac frequency, increase in LVPs, MAP and total peripheral resistances (TPR), which were associated with a decrease in CO. Finally, phase III, that occurred about 90 sec after PAF infusion, was characterized by marked ECG changes (ST segment depression and conduction arrhythmias), a decrease in LVPs and MAP, as well as a rise in TPR and in right atrial pressure (RAP). All these alterations were reversible within 30–60 min. Pretreatment with promethazine and cimetidine, as H₁ and H₂ histamine receptor antagonists, markedly prevented the development of phase II, namely the rise in cardiac frequency, LVPs, MAP and TPR, but did not significantly modify phase I and III. In contrast, pretreatment with indomethacin, an inhibitor of cyclooxygenase, moderatively attenuated, but did not abolish, the three phases of cardiovascular changes induced by PAF infusion.     

Heterogeneous pattern of chromosomal breakpoints involving the MYC locus in multiple myeloma

Chromosomal rearrangements of the MYC locus, which often involve the IG loci, are recurrent events in multiple myeloma (MM) and plasma cell leukemia (PCL). We used dual-color fluorescence in situ hybridization (FISH) to characterize the breakpoint locations of chromosomal translocations/rearrangements involving the MYC locus at 8q24 found in a panel of 14 MM cell lines and 70 primary tumors (66 MM and 4 PCL). MYC locus alterations were observed in 21 cases: MYC/IG (mainly IGH@) fusions in 11 cell lines and three patients (2 MM and 1 PCL), and extra signals and/or abnormal MYC localizations in seven patients (5 MM and 2 PCL). Fourteen of these cases were investigated by FISH analyses by use of a panel of BAC clones covering about 6 Mb encompassing the MYC locus. The breakpoints were localized in a region 100-250 kb centromeric to MYC in four cases, a region 500-800 kb telomeric to the gene in four cases, and regions > or = 2 Mb centromeric or telomeric to MYC in five cases. Two different breakpoints were detected in the KMS-18 cell line, whereas the insertion of a MYC allele was found in a complex t(16;22) chromosomal translocation in the RPMI8226 cell line. Our data document a relatively high dispersion of 8q24 breakpoints in MM.     

Laparoscopic ICG-guided RALPPS procedure for HCC on cirrhosis with 3D reconstruction implementation: a case report

We present a fully laparoscopic partial RALPPS (radiofrequency-assisted liver partition with portal vein ligation for staged hepatectomy) on a cirrhotic 71-year...     

Assessing parasitic infestation of vegetables in selected markets in Metro Manila,Philippines

ObjectiveTo assess the parasitic infestation of vegetables in selected markets in Metro Manila, Philippines.MethodsA total of 80 vegetables were purchased from public and private markets in Munoz, Quezon City, and Alabang, Muntinlupa City. Vegetables were washed, and the washings were collected and examined for parasitic organisms.ResultsIn all vegetables examined, 36 of 80 (45.0%) were infested with parasitic organisms. Vegetables obtained from Muntinlupa City showed that 17 of 40 (42.5%) have parasitic infestation as compared with those obtained from Quezon City with 19 of 40 (47.5%). Significant differences on the parasitic organisms existed between the public and private markets and between the two locations (P<0.05).ConclusionsFindings indicate that vegetables can be potential source of parasitic infection. There is a need to be vigilant in ensuring that foodstuffs sold in our market systems are safe and fit for consumption.