Membrane expression of platelet calpain

Platelet calpain has many platelet substrates, including external membrane proteins. We thus investigated whether platelet calpain II was associated with platelet membranes in unstimulated and thrombin- activated platelets. A monospecific, goat polyclonal antibody was reared to purified platelet calpain II. Sixteen whole platelet lysates were found to contain 4.5 +/- 0.7 micrograms calpain antigen II per 10(8) platelets (mean +/- SEM) as determined by a competitive enzyme- linked immunosorbent assay. Using the dipeptide fluorogenic substrate, Suc-Leu-Tyr-MCA, 17 human platelet lysates contained 3.6 +/- 0.4 micrograms calpain activity per 10(8) platelets. Platelet calpain II was associated with the Triton X-100 insoluble platelet cytoskeletons from both unstimulated and thrombin-activated platelets. When compared with the total cell content of platelet calpain II, calpain antigen (10% to 13%) and calpain activity (24% to 28%) was associated with platelet cytoskeletons in unstimulated and thrombin-activated platelets, respectively. On immunoblot, the heavy chain (80 Kd) of calpain II was detected in platelet cytoskeletons. Subcellular fractionation studies on both unstimulated and thrombin-activated platelets, revealed that half of the total platelet calpain II antigen was associated with cytosol, and the other half was associated with the membrane fraction. Platelet calpain II was not seen on the surface of unstimulated, paraformaldehyde fixed platelets by immunofluorescence. However, on thrombin-activated platelets, rim immunofluorescence was seen, indicating that activated platelets externalize their calpain. This observation was confirmed by the finding that about 2,000 molecules per platelet of an 125I-anti-calpain II Fab' specifically bound to thrombin-activated but not unstimulated platelets. Both dibucaine (1 mmol/L) and platelet activating factor (1.86 mumol/L) in the absence of external Ca++, but not collagen (5 micrograms/mL) or ionophore A23187 (2.5 mumol/L) in the absence of external Ca++, were also able to externalize platelet calpain II antigen, as indicated by a similar level of specific 125I-anti-calpain II Fab'-platelet binding. These combined studies indicate that platelet calpain II is a major protein, comprising 2% of total platelet protein, a substantial portion of which is membrane-associated. When platelets are activated by thrombin and platelet activating factor, calpain II antigen also becomes present on the external platelet surface.     

Evidence for a physiological role of gonadotropin-releasing hormone (GnRH) or GnRH-like material in the ovary

The possibility that GnRH or a GnRH-like material of ovarian origin may play a physiological role in follicular development was explored in immature hypophysectomized rats by testing whether a potent synthetic antagonist of GnRH action [( N-acetyl-dehydro-Pro1,D-p-chloro-Phe2,D-Trp3,6]GnRH), would potentiate FSH-induced maturation of ovarian follicles to an ovulable stage. Rats were hypophysectomized on day 25 of their life and implanted with a Silastic capsule containing diethylstilbestrol. On day 30, they were started on injections of 10 micrograms NIH FSH-S12 twice daily alone (control) or in combination with 10 micrograms of either native GnRH or GnRH antagonist. On day 35, all rats received 30 IU hCG to trigger ovulation and luteinization of mature follicles. Rats were killed 25.5-28 h later and inspected for number of ova in Fallopian tubes, ovarian weight, number of corpora lutea (CL) on ovarian surface, and appearance of hematoxylin-eosin-stained ovarian slices. In control animals (n = 6), we found some ovulations (mean +/- SEM, 3.2 +/- 1.1/rat), many more CL (16.5 +/- 4.5/rat), and ovarian weights of 37.7 +/- 1.1 mg/rat. In GnRH-treated rats (n = 5), there were no CL formed, no ova were found, and ovarian weights were 16.0 +/- 1.5 mg/rat. In contrast, in GnRH antagonist-treated rats (n = 5), 16.4 +/- 1.6 ova/rat were recovered from the Fallopian tubes, and ovaries contained 20.8 +/- 2.5 CL/rat and weighed 52.7 +/- 3.2 mg/rat. All changes were statistically significant. We conclude that an antagonist of GnRH action is able to potentiate the action of FSH on ovarian follicle development and suggest that it does so by inhibiting the action of an endogenous GnRH or GnRH-like substance that may play a role as a physiological atretic signal.     

Diabetes and orthopaedic surgery: a review

Diabetes mellitus (DM) is common, estimated to affect 425 million people worldwide in 2017. It is a condition that is continually growing in prevalence and is often associated with multiple co-morbidities. Its multi-system effects on the body mean that its management can pose a challenge, even to more experienced clinicians. In orthopaedic practice, diabetic patients are commonly encountered owing to their increased fracture risk and complications of the disease such as diabetic foot. An appropriate knowledge of diabetes, its pathophysiology, immunology and the pharmacology of medications used in its treatment is essential, as the consequences of mismanagement can be grave. Optimal treatment of diabetics can often require the involvement of a wider multidisciplinary team. Complications that can be encountered in the perioperative and postoperative periods include, diabetic ketoacidosis, hyperosmolar hyperglycaemic state, surgical site infection and venous thromboembolism. This review outlines current concepts in the perioperative management of diabetes and its manifestations within orthopaedic surgery, with a focus on outcomes and complications. A review of the available literature reveals conflicting conclusions between studies, with no clear effect or consensus yet established for many issues. There is a need for a greater number of well-designed, high-quality, appropriately powered trials to establish the true effect of diabetes on outcomes in orthopaedic surgery.     

Selenium Deficiency After Bariatric Surgery,Incidence and Symptoms: a Systematic Review and Meta-Analysis

Obesity Surgery - This study review the prevalence of selenium deficiency after bariatric surgery, incidence, and symptoms. A systematic literature search and meta-analysis was performed...     

Importance of catalase in the disposal of hydrogen peroxide within human erythrocytes

The catalase within normal, intact human erythrocytes was completely inactivated with amino triazole. The rate of 14CO2 evolution, when the cells were subsequently incubated with 14C-labeled glucose, provided a measure of the rate at which NADPH was being oxidized by the glutathione peroxidase/reductase system for the disposal of H2O2. This rate was determined in control cells and in catalase-inactivated cells while the cells were exposed to H2O2, which was generated at various constant and predetermined rates by glucose oxidase. The results indicated that catalase handles approximately half of the generated H2O2. The glutathione peroxidase/reductase mechanism accounted for the other half. These results are in agreement with our earlier findings on erythrocytes of a subject with a genetic deficiency of catalase. However, an unexpected result with the present approach was the finding that the increased dependence on the glutathione peroxidase/reductase mechanism did not occur until greater than 98% of the catalase had been inactivated. The latter observation indicates that catalase and the glutathione peroxidase/reductase system function intracellularly in a manner very different from that previously ascribed to them. An explanation of the findings requires that the two methods of H2O2 disposal function in a coordinated way, such as a sequential action in which the glutathione peroxidase/reductase system is the rate-limiting step.     

Antimicrobial Activities of Skincare Preparations from Plant Extracts

In this study, Tithonia diversifolia Helms. (A Gray), Aloe secundiflora (Miller) and Azadirachta indica (A. Juss) plant extracts were used to make herbal soaps while Thevetia peruviana (Schum) seed oil was used to make a herbal lotion for skincare. The soaps were tested for the growth inhibition of Escherichia coli, and Candida albicans. The lotion was evaluated against Staphylococcus aureus and E.coli. Although Tithonia diversifolia soap exhibited the highest inhibitory effect on the test bacterial strains, it had the least inhibition against C. albicans. Results from this study indicated that the ‘Tithonia diversifolia’ soap would have superior skin protection against the tested bacteria but would offer the least skin protection against C. albicans. The herbal lotion inhibited S. aureus and E. coli in a concentration dependent manner, however, the inhibitory effect was more pronounced on S. aureus.     

Association between the estrogen receptor beta gene and age of onset of Parkinson's disease

The purpose of this study was to investigate the potential contribution of genetic variants in the estrogen receptor beta gene to the aetiology of Parkinson's disease (PD). Several lines of evidence from human and animal studies suggest a protective role for estrogen in PD. Recently the estrogen receptor beta subtype was reported to be an important mediator of estrogen actions in the nigrostriatal dopamine system. Two single nucleotide polymorphisms at position 1730 and 1082 in the ER beta gene were genotyped, using pyrosequencing, in 260 patients with PD and 308 controls recruited from the Swedish population. Neither of the two estrogen receptor beta polymorphisms was associated with an increased risk for PD. However, the G allele of the A1730G polymorphism was more frequent in patients with an early age of onset than in patients with a late age of onset of PD (P = 0.006). Patients carrying the GG genotype had an odds ratio of 2.2 for having an early onset of PD compared to non-carriers. In conclusion, our results indicate that genetic variation in the estrogen receptor beta gene may influence the age of onset of PD.