Glutamate Toxicity: An Experimental and Theoretical Analysis

In slices of 8-day-old rat cerebellum, the lowest concentration of glutamate that induced toxicity (30 min exposure; 90 min recovery) was 100 microM, but the damage only occurred in the outermost regions. As the concentration was raised, the band of necrosis became progressively deeper until, at 3 mM, it was uniform across the slice thickness. At a test concentration of 300 microM, the width of the necrotic band did not change when either the exposure time or the recovery period was varied between 30 min and 3 h. These results are predicted by a theoretical model in which the diffusion of glutamate into brain tissue is countered by cellular uptake of the amino acid, and they argue against the idea that glutamate toxicity is inherently self-propagating. When slices were examined immediately after exposure (300 microM), a prominent swelling of glial cells was present at the slice surface. Swelling per se did not appear to compromise their uptake function, and the model predicts that cellular swelling, by reducing the rate of diffusion of glutamate, protects against glutamate toxicity. The damage produced by 3 mM glutamate, which was primarily exerted against granule cells, was prevented by N-methyl-d-aspartate (NMDA) receptor blockade, whereas antagonists acting at alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors were ineffective. Under conditions of energy deprivation, the neurotoxic potency of glutamate was markedly enhanced and a normally non-toxic concentration (30 microM) became maximally toxic towards granule cells. Dark vacuolar degeneration of Purkinje cells was also present, and this could be inhibited by blocking AMPA receptors. The results and theoretical analysis suggest that intact brain tissue is remarkably resistant to glutamate toxicity, chiefly because of the formidable properties of the uptake system. However, under special circumstances, glutamate can become a potent neurotoxin and its toxicity can then involve both NMDA and AMPA receptors.     

What is the effect and mechanism of kinesiology tape on muscle activity?

Objective

This study aimed to evaluate the effects of kinesiology tape, anesthesia, and kinesiology tape along with anesthesia, on motor neuron excitability.

Effect of anodal and cathodal microamperage direct current electrical stimulation on injury potential and wound size in guinea pigs

Injury potential may have a regulatory role in the wound healing process, and exogenous electrical stimulation (ES) may mimic natural endogenous bioelectric current that can improve wound healing. Until now, the influence of externally applied ES on injury potential has not been demonstrated during the healing of acute wounds. Thirty-nine male guinea pigs were randomly divided into a control group (sham treatment) and two experimental groups: anodal and cathodal direct current (DC). A 2.5 cm-long full-thickness skin incision was made on each animal's dorsal region. Differential skin surface potential was measured before and immediately after the injury and also through day 21 of the healing period; wound surface area (WSA) was also measured throughout the 21-day healing period. Immediately after injury, wound potential significantly increased in all three groups, reaching a maximum on day 1 for the control and cathodal groups and day 3 for the anodal group (p < 0.05), then decreasing through the healing period. Wound potential returned to preinjury levels by the end of the healing period in the anodal group only. By days 19 and 21, wound potential had decreased more for the anodal group than the control group (p < 0.05). By day 15 for the anodal group and day 17 for the cathodal group, WSA had decreased more compared with the control group (p < 0.05). Anodal microamperage DC ES is appropriate for improving the healing of acute skin wounds because it causes both the wound surface to close and the wound potential to return to preinjury levels faster.     

Sites ofd-[H]aspartate accumulation in mouse cerebellar slices

Slices of mouse cerebellar vermis, cut in the parasagittal plane, were incubated for various times (up to 3 h) in the presence of 1μMd-[³H]aspartate, a non-metabolized substrate for the glutamate/aspartate carrier in brain tissue. Light microscopic autoradiography indicated that in regions away from the cut edges of the slices the amino acid accumulated in glia and granule cells. Relatively few grains were seen over Purkinje, Golgi, stellate and basket cells or over white matter. Grain counts over the granule cell layers in the middle parts of the sliced indicated that after short (15 min) exposures to the labelled substrate, non-granule cell areas (which included glia) contained, on average, slightly more grains than granule cells but wit longer exposures (1.5 and 3 h) the relative grain density over granule cells became much higher, possibly because glial uptake preventsd-[³H]aspartate gaining access to neuronal sites in adequate amounts during short incubations and/or because the longer incubations allow time for retrograde migration of the label from parallel fibre terminals to occur. The demonstration of selective uptake ofd-[³H]aspartate into granule cells contrasts with previous autoradiographic results (possible reasons for which are discussed) and supports the notion thatl-glutamate is the transmitter of granule cells. The results also have a bearing on the importance of the metabolic compartmentation of glutamate in relation to its proposed transmitter role.     

Pessary use in advanced pelvic organ prolapse

The objective of this study was to review our experience with pessary use for advanced pelvic organ prolapse. Charts of patients treated for Stage III and IV prolapse were reviewed. Comparisons were made between patients who tried or refused pessary use. A successful trial of pessary was defined by continued use; a failed trial was defined by a patients discontinued use. Thirty-two patients tried a pessary; 45 refused. Patients who refused a pessary were younger, had lesser degree of prolapse, and more often had urinary incontinence. Most patients (62.5%) continued pessary use and avoided surgery. Unsuccessful trial of pessary resorting to surgery included four patients (33%) with unwillingness to maintain, three patients (25%) with inability to retain and two patients (17%) with vaginal erosion and/or discharge. Our findings suggest that pessary use is an acceptable first-line option for treatment of advanced pelvic organ prolapse.     

Fine-needle aspiration cytology and flow cytometric immunophenotyping in diagnosis and classification of non-Hodgkin lymphoma in comparison to histopathology

This prospective study aimed to compare the value of fine needle aspiration (FNA) cytology (FNAC) and flow cytometric immunophenotyping (FCI) with histopatopathology (HP) in the diagnosis and classification of non-Hodgkin lymphoma (NHL). Twenty-nine excised lymph nodes suspected of NHL were evaluated using FNAC, FCI, and HP. Specimens were divided into two equal parts; one for HP and the other for FNAC and FCI. Results were compared in terms of diagnosis (malignant, benign or reactive, and metastatic) and NHL class. With combined FNAC/FCI, 11 (37.9%) cases were diagnosed as NHL, 11 cases (37.9%) as reactive lymph node, six cases (20.6%) as Hodgkin's lymphoma, and one case (3.4%) as metastasis. HP revealed nine cases (31%) of NHL, five cases (17.2%) of reactive lymph nodes and all the diagnosed metastatic and Hodgkin's lymphoma. Considering histology as a gold standard method in diagnosis, the sensitivity, specificity, PPV and NPV of FNAC/FCI in differentiate malignant and benign lesion were 73.9%, 83.3%, 94.4%, and 45.5%, respectively and in differentiate NHL from others were 75%, 93.8%, 90%, and 83.3%, respectively. Cytology and HP in addition to FCI and HP are significantly different from determination of NHL lesions point of view (P = 0.001 and P < 0.0001, respectively). However, FCI can be considered as an adjunctive method for Cytology especially because Cytology is not competent enough to differentiate between benign lesions and Lymphoma. Additionally, FCI is shown to be an accurate method in classifying NHL.     

Automatic evaluation of pressure sore status by combining information obtained from high-frequency ultrasound and digital photography

In this study, the different phases of pressure sore generation and healing are investigated through a combined analysis of high-frequency ultrasound (20 MHz) images and digital color photographs. Pressure sores were artificially induced in guinea pigs, and the injured regions were monitored for 21 days (data were obtained on days 3, 7, 14, and 21). Several statistical features of the images were extracted, relating to both the altering pattern of tissue and its superficial appearance. The features were grouped into five independent categories, and each category was used to train a neural network whose outputs were the four days. The outputs of the five classifiers were then fused using a fuzzy integral to provide the final decision. We demonstrate that the suggested method provides a better decision regarding tissue status than using either imaging technique separately. This new approach may be a viable tool for detecting the phases of pressure sore generation and healing in clinical settings.     

Prevalence of bacterial vaginosis in pregnant and non-pregnant Iranian women: a systematic review and meta-analysis

Purpose

Bacterial vaginosis (BV) is a vaginal disorder which occurs either symptomatic or asymptomatic because of an imbalance between H₂O₂-producing Lactobacillus and Gardnerella vaginalis in the vagina. This systematic review and meta-analysis is the first to determine the prevalence of BV in pregnant and non-pregnant women in Iran.

Methods

We used national (SID, Irandoc, Iranmedex and Magiran) and international (PubMed, Scopus, Google Scholar and ISI web of knowledge) electronic databases to systematically search and collect available studies using related keywords (up to 1 December 2017). Inclusion and exclusion criteria were defined to select eligible studies.

Results

The overall prevalence of BV among Iranian women was 18.9% (95% CI 14–25). Gardnerella vaginalis was the most prevalent isolated bacteria. The prevalence of BV in non-pregnant women was 28% (95% CI 15.1–45.9) which was higher compared with pregnant women who had a prevalence of 16.5% (95% CI 12.5–21.6).

Conclusion

The present review revealed a high prevalence of BV in non-pregnant women. Given that BV is associated with a series of reproductive complications such as infertility, taking preventive measures such as awareness of patients as well as monitoring and controlling of syndrome are essential.