Deficits in motor performance after pedunculopontine lesions in rats – impairment depends on demands of task

Anatomically and functionally located between basal ganglia and brainstem circuitry, the pedunculopontine tegmental nucleus (PPTg) is in a pivotal position to contribute to motor behavior. Studies in primates have reported akinesia and postural instability following destruction of the PPTg. In humans, the PPTg partially degenerates in Parkinson's disease and stimulation of this region is under investigation as a possible therapeutic. Studies in rats report no crude motor impairment following PPTg lesion, although a detailed assessment of the role of the PPTg in rat motor function has not been reported. Our studies applied motor tests generally used in rodent models of Parkinson's disease to rats bearing either excitotoxic damage to all neuronal populations within PPTg, or selective destruction of the cholinergic subpopulation created with the toxin Dtx‐UII. Neither lesion type altered baseline locomotion. On the rotarod, excitotoxic lesions produced a persistent impairment on the accelerating, but not fixed speed, conditions. In the vermicelli handling task (a quantitative measure of fine motor control and effective behavioral sequencing) excitotoxic lesions produced no single impairment, but globally increased the number of normal and abnormal behaviors. In contrast, depletion of cholinergic PPTg neurons produced impairment on the accelerating rotarod but no changes in vermicelli handling. Together, these results show that while PPTg lesions produce no impairment in the execution of individual motor actions, impairments emerge when the demands of the task increase. Results are discussed in terms of PPTg acting as part of a rapid action selection system, which integrates sensory information into motor output.     

Photodynamic antibacterial effect of graphene quantum dots

Synthesis of new antibacterial agents is becoming increasingly important in light of the emerging antibiotic resistance. In the present study we report that electrochemically produced graphene quantum dots (GQD), a new class of carbon nanoparticles, generate reactive oxygen species when photoexcited (470 nm, 1 W), and kill two strains of pathogenic bacteria, methicillin-resistant Staphylococcus aureus and Escherichia coli. Bacterial killing was demonstrated by the reduction in number of bacterial colonies in a standard plate count method, the increase in propidium iodide uptake confirming the cell membrane damage, as well as by morphological defects visualized by atomic force microscopy. The induction of oxidative stress in bacteria exposed to photoexcited GQD was confirmed by staining with a redox-sensitive fluorochrome dihydrorhodamine 123. Neither GQD nor light exposure alone were able to cause oxidative stress and reduce the viability of bacteria. Importantly, mouse spleen cells were markedly less sensitive in the same experimental conditions, thus indicating a fairly selective antibacterial photodynamic action of GQD.     

Force–velocity relationship of leg extensors obtained from loaded and unloaded vertical jumps

Purpose

Resent research has suggested that loaded multi-joint movements could reveal a linear force–velocity (F–V) relationship. The aim of the present study was to evaluate the F–V relationship both across different types of vertical jumps and across different F and V variables.

Methods

Ten healthy subjects performed maximum various vertical jumps that were either loaded or unloaded by constant external forces of up to 30 % of their body weight. Both the maximum and averaged F and V data were recorded.

Results

The observed F–V relationships proved to be strong (median correlation coefficients ranged 0.78–0.93) and quasi-linear. Their F- and V-intercepts and the calculated maximum power (P) were highly reliable (0.85 < ICC < 0.98), while their concurrent validity with respect to their directly measured values was on average moderate-to-large. The obtained F–V relationships also revealed that (1) the assessment of maximum F and P could be somewhat more reliable and valid than the assessment of maximum V, (2) natural countermovement jumps should be employed rather than the jumps performed from a fixed squat position, while (3) both maximum and averaged F and V variables could be used despite revealing markedly different regression parameters.

Conclusions

The data generally reveal a reliable, valid, strong and quasi-linear F–V relationship across variety of vertical jumps and the recorded F and V variables. Therefore, we conclude that the loaded vertical jumps could be developed into a routine method for testing the force, velocity, and power generating capacity of leg extensors.     

Trisomy 15 mosaic derived from trisomic conceptus: Report of a case and a review

We report on a fetus with 47,XX,+15 chromosome abnormality detected on chorionic villus sampling (CVS). The pregnancy was terminated at 15.5 weeks of gestation and chromosome analysis done on amniocytes and fetal tissues showed a karyotype 46,XX/47,XX,+15. Autopsy showed multiple abnormalities. Short-arm polymorphisms of the three number 15 chromosomes were highly informative in the delineation of parental origin and the stage of meiotic error. Using fluorescent in situ hybridization (FISH) with D15Z1 and a chromosome 15 painting probe, in addition to DA/DAPI and G-banding, we were able to show that the trisomic conceptus was derived through maternal meiosis I error. The trisomic state was then partially corrected by the loss of one of the two maternal 15s resulting in mosaicism without uniparental disomy (UPD). Striking differences in the proportion of trisomic cells in kidneys, blood, intestine, and skin, and lower proportions of trisomic cells in transformed and frozen than in fresh tissues, illustrate the continuing cell selection in this fetus in favour of the normal cell line. Trisomy 15 conceptions are usually aborted spontaneously in the first trimester of pregnancy. The longer survival of this fetus is most probably the result of a chromosome 15 loss from the trisomic zygote. To the best of our knowledge, the presence of this lethal trisomy has been reported in only five live-born infants, and in five fetuses including the present case, it was detected prenatally and the pregnancies were terminated. © 1996 Wiley-Liss, Inc.     

Predictors of Mucosal and Muscle Pain in Vulvodynia: A Cross-Sectional Analysis From the National Vulvodynia Registry

Diagnostic criteria for provoked vestibulodynia (PVD) rely on mucosal pain in the vulvar vestibule, with less emphasis on pain from pelvic floor muscles. It is unknown how psychosocial variables associated with PVD are differentially associated with mucosal versus muscle pain. Analysis of data from the National Vulvodynia Registry (n = 202) revealed several factors associated with increased mucosal pain: pain duration (P = .043), the McGill sensory subscore (P = .0086) and the Gracely pain scale (P< .001). Increased mucosal pain was also associated with decreased arousal (P = .036). On the other hand, factors significantly associated with greater muscle pain included number of comorbid pain conditions (P = .001), decreased intercourse frequency post PVD onset (P = .02) and higher scores on the McGill sensory (P = .0001) and affective (P = .0002) subscores, the Gracely pain scale (P = .0012), and state anxiety (P < .001). Sexual function was also significantly impacted by high pelvic floor muscular pain, with lower scores for arousal (P = .046), orgasm (P = .0014) and satisfaction (P = .013), and higher pain (P = .01). Significant differences in the relationship between muscle and mucosal pain for pain duration (P = .005), McGill affective score (P = .001), orgasm (P = .049), change in intercourse frequency (P = .027), and state anxiety (P = .030) suggest the possibility of mucosal or muscle pain predominant PVD subtypes.PerspectivePatients with higher pelvic floor muscle pain scores than mucosal pain scores may represent different subgroups or characteristics of patients with provoked vestibulodynia. This research highlights the importance of assessment of the pelvic floor muscles in addition to the cotton swab test of the vestibule.     

Acquired C1 esterase inhibitor deficiency

Acquired C1 esterase inhibitor deficiency is a rare condition associated with autoimmune or low-grade lymphoproliferative disorders. Adults or elderly patients are most commonly affected. The diagnosis is suspected when patients present with recurrent angioedema and low serum levels of C4 with normal levels of C3. Low levels of C1q and low C1 esterase inhibitor activity confirm the diagnosis. In this paper, we summarize experience with 22 cases of acquired C1 esterase inhibitor deficiency in the context of a review of the published literature on diagnosis and treatment of this condition.