Fibronectin binding to thrombin-stimulated platelets: evidence for fibrin(ogen) independent and dependent pathways

Plasma fibronectin binds in a specific and saturable manner to thrombin- stimulated platelets. gamma-Thrombin stimulated 80% as much fibronectin binding to platelets as alpha-thrombin with conversion of less than or equal to 1% of platelet fibrinogen to fibrin. Afibrinogenemic and normal platelets bound similar quantities of fibronectin in the presence of calcium or magnesium-ethylene glycol tetra-acetic acid (EGTA). These observations indicate that fibronectin can interact with platelets without involvement of fibrin or fibrinogen. Nevertheless, two different effects of fibrin(ogen) on fibronectin binding were observed. First, exogenous fibrinogen inhibited fibronectin binding to thrombin-stimulated platelets. This inhibition was unidirectional, as fibronectin did not inhibit fibrinogen binding to ADP or thrombin- stimulated cells. Second, formaldehyde-fixed cells with surface- associated fibrin bound significant quantities of fibronectin. This interaction required calcium and did not occur on fixed cells with or without surface-bound fibrinogen. A portion of the ligand bound to fixed cells with surface-associated fibrin was modified to form a derivative with a molecular weight identical to that of the fibronectin subunit cross-linked to the alpha-chain of fibrin. This high mol wt derivative was also observed to a variable extent with living cells in the presence of magnesium or calcium but not in the presence of magnesium-EGTA. Thus, fibronectin binds to platelets by at least two mechanisms: (1) a fibrin(ogen)-independent pathway that requires divalent ions and is inhibited by exogenous fibrinogen; and (2) a fibrin-dependent pathway with an absolute calcium requirement. With nonaggregated, thrombin-stimulated platelets, the former pathway appears to predominate.     

Existential neuroscience: effects of mortality salience on the neurocognitive processing of attractive opposite-sex faces

Being reminded of the inherently finite nature of human existence has been demonstrated to elicit strivings for sexual reproduction and the formation and maintenance of intimate relationships. Recently, it has been proposed that the perception of potential mating partners is influenced by mortality salience. Using functional magnetic resonance imaging, we investigated the neurocognitive processing of attractive opposite-sex faces after priming with death-related words for heterosexual men and women. Significant modulations of behavioral and neural responses were found when participants were requested to decide whether they would like to meet the presented person. Men were more in favor of meeting attractive women after being primed with death-related words compared to a no-prime condition. Increased neural activation could be found under mortality salience in the left anterior insula and the adjacent lateral prefrontal cortex (lPFC) for both men and women. As previously suggested, we believe that the lPFC activation reflects an approach-motivated defense mechanism to overcome concerns that are induced by being reminded of death and dying. Our results provide insight on a neurocognitive level that approach motivation in general, and mating motivation in particular is modulated by mortality salience.     

Efficacy of Crocus sativus L. on reduction of cadmium‐induced toxicity on spermatogenesis in adult rats

Cadmium is a toxic heavy metal element, which probably cause infertility by impairment in spermatogenesis. The present work aimed (i) to study the toxic effect of cadmium on spermatogenesis in rat, as well as (ii) the protective effect of Crocus sativus L. on cadmium‐intoxicated rats. Cadmium chloride was administered intraperitoneally during 16 days at intervals of 48 h between subsequent treatments. Crocus sativus L. was pre‐treated in both of control and cadmium‐injected rats. Animals were sacrificed on day 17 after the first treatment. The left cauda epididymis was removed and immediately immersed into Hank's balanced salt solution for the evaluation of sperm count and viability, and left testis was fixed in 10% formalin for histological evaluation. Following contamination with cadmium, a decrease was observed in the number and viability of cauda epididymis sperm, which were increased by Crocus sativus L. pre‐treatment (P < 0.05). In addition, cadmium decreased both cell proliferation and Johnsen Scores in the seminiferous tubules, which were reversed by Crocus sativus pre‐treatment (P < 0.05). Furthermore, cadmium‐induced decrease in the amount of free serum testosterone as well as an increase in lipid peroxidation activity in the testicular tissue was reversed by Crocus sativus L. (P < 0.05). These findings may support the concept that Crocus sativus L. can improve the cadmium toxicity on spermatogenesis.     

Early and late visual prognosis in solar retinopathy

Background: Solar retinopathy was observed in a total of 86 eyes of 58 patients following the solar eclipse over Turkey in April 1976. The visual prognosis and the presence of late complications were evaluated at the early and late periods. Methods: Of the 58 patients, 34 (51 eyes) presented during the first week and came for follow-up examination in the succeeding week, also after 1, 3, 12 and 18 months. After that they were examined at yearly intervals (mean 4.2 years). Twenty-four patients (35 eyes) presented during the period between 1 and 11 years post-eclipse and were followed up for a mean period of 3.4 years. After a period of 15 years, all of the patients were invited for re-examination and nine patients (14 eyes) attended. Results: The improvement in visual acuity was observed to have taken place mostly during the first 2 weeks to 1 month after the eclipse. Further improvement in visual acuity was not observed in any of the eyes after the 18-month examination. The improvement in visual acuity was more prominent and earlier in the eyes that had visual acuity of 0.2 or better initially. Only the eyes with initial visual acuity equal to or better than 0.4 had a chance to improve their acuity to 10/10. Having observed the 51 eyes for mean period of 4.2 years and the 35 eyes for 3.4 years, no change in visual acuity was observed. Among the total of 86 eyes, 9 were found to have pseudolamellar macular holes. Conclusion: Correlation was found between initial visual acuity and the funduscopic appearance after the 2nd week. Fluorescein angiography was not found to be a conclusive test in solar retinopathy. No late complications were observed.     

Molecular Study of Sheep Malignant Theileriosis at Barka Region in the Sultanate of Oman

Background

We used the PCR technique based on the abovementioned primer pair and sequencing to demonstrate the Theileria infection in the sheep samples collected from Sultanate of Oman.

Methods

According to the frame work of “integrated control of ticks and tick borne diseases in globalized world managed by EU-ICTTD-3 project, the samples from blood, liver, spleen, lymph node and lung were sent to the laboratory of Iranian Research Center for Ticks and Tick-borne Diseases (IRCTTD). Samples from blood smear and impression smears from liver, spleen, lymph node, and lung were analyzed by Geimsa staining. The DNA was extracted from the abovementioned samples and analyzed by PCR technique using specific primers derived from the nucleotide sequences of 18S rRNA gene of T. lestoquardi, which can amplify the common region in other Theileria and Babesia spp. Subsequently the amplified DNA was sequenced.

Results

The analysis of blood smears of the sheep was negative for piroplasmosis performed through the Giemsa staining. The impression smears prepared from liver, spleen, lymph node, and lung showed suspicious structures mimicking Theileria schizonts in some cells. The results showed an expected PCR product of 428 bp in length, which is specific for Theileria spp. The PCR products were subsequently sequenced. The corresponding nucleotide sequence is registered under accession number {"type":"entrez-nucleotide","attrs":{"text":"JF309152","term_id":"323695911","term_text":"JF309152"}}JF309152 in GenBank. The sequence alignment in GenBank showed that the PCR products had 99% homology to the known T. lestoquardi registered under accession number {"type":"entrez-nucleotide","attrs":{"text":"AF081135","term_id":"7576455","term_text":"AF081135"}}AF081135 in the GenBank.

Conclusion

Oman sheep are highly susceptible for Theileria infection and the infected sheep mostly die before the microschizonts or erythrocytic form of Theileria appears in the nucleated or erytrocytic cells respectively.     

Decreased Basal Metabolic Rate Can Be an Objective Marker for Sarcopenia and Frailty in Older Males

Objectives

The aim of this study is to demonstrate the ability of the basal metabolic rate (BMR) to detect frailty and sarcopenia in older males.