Magnolol, a major bioactive constituent of the bark of Magnolia officinalis, exerts antiepileptic effects via the GABA/benzodiazepine receptor complex in mice

BACKGROUND AND PURPOSE

The aim of this study was to evaluate the anti-convulsant effects of magnolol (6, 6', 7, 12-tetramethoxy-2, 2'-dimethyl-1-β-berbaman, C18H18O2) and the mechanisms involved.

EXPERIMENTAL APPROACH

Mice were treated with magnolol (20, 40 and 80 mg·kg(-1)) 30 min before injection with pentylenetetrazol (PTZ, 60 mg·kg(-1), i.p.). The anti-seizure effects of magnolol were analysed using seizure models of behaviour, EEG and in vitro electrophysiology and c-Fos expression in the hippocampus and cortex.

KEY RESULTS

Magnolol at doses of 40 and 80 mg·kg(-1) significantly delayed the onset of myoclonic jerks and generalized clonic seizures, and decreased the seizure stage and mortality compared with those of the vehicle-treated animals. EEG recordings showed that magnolol (40 and 80 mg·kg(-1)) prolonged the latency of seizure onset and decreased the number of seizure spikes. The anti-epileptic effect of magnolol was reversed by the GABA(A)/benzodiazepine receptor antagonist flumazenil. Pretreatment with flumazenil decreased the effects of magnolol on prolongation of seizure latency and decline of seizure stage. In a Mg(2+)-free model of epileptiform activity, using multi-electrode array recordings in mouse hippocampal slices, magnolol decreased spontaneous epileptiform discharges. Magnolol also significantly decreased seizure-induced Fos immunoreactivity in the piriform cortex, dentate gyrus and hippocampal area CA1. These effects were attenuated by pretreatment with flumazenil.

CONCLUSIONS AND IMPLICATIONS

These findings indicate that the inhibitory effects of magnolol on epileptiform activity were mediated by the GABA(A) /benzodiazepine receptor complex.

Ear size as a predictor of chronological age

It is generally observed that older people have bigger ears and noses. Cartilage is known to alter in structure with age. We conducted a cross sectional study to verify the trend between age and the size of two cartilaginous structures, ear and nose. A total of 100 young individuals were compared to older individuals with respect to their ear and nose sizes. We found that the greatest correlation coefficient of age was with ear circumference, and the linear regression equation being: Ear circumference = 88.1 + (0.51 x subject's age). Except for the ear tragus, which correlated insignificantly with age, anatomical variables of the ear had higher correlation with age than anatomical variables of the nose. This study supports the view that as people age, their ears get larger, particularly the ear circumference, which increases on average 0.51 mm per year. This enlargement is likely associated with aging changes of collagen. The knowledge from this study allows us to calculate the age of an individual based on ear size: Subject's age = 1.96 x (Ear circumference in millimeters - 88.1).

The retinal "lozenge" or "dull macular reflex" in Alport syndrome may be associated with a severe retinopathy and early-onset renal failure

BACKGROUND AND AIMS

Alport syndrome is an inherited disease with renal failure, and often a hearing loss, lenticonus and dot-and-fleck retinopathy. A retinal "lozenge" or "dull macular reflex" has been described in some patients. This study determined the prevalence and significance of this sign.

METHODS

Twenty-three patients from 14 families with X linked Alport syndrome and seven from four families with autosomal recessive disease underwent slit-lamp biomicroscopy for lenticonus, direct and indirect ophthalmoscopy, and photography for the retinopathy.

RESULTS

The lozenge was present in five males (38%) but no females with X linked Alport syndrome, as well as one individual with recessive disease (1/7, 14%). It resulted from the sharp demarcation between the normal fovea and a perifoveal annnulus of confluent dots and flecks that were obvious with magnification of retinal photographs. The lozenge was first noted in adolescence and was always associated with early-onset renal failure, hearing loss and lenticonus.

CONCLUSION

Clinicians must be aware that the "lozenge" or "dull macular reflex" described in Alport syndrome is not a normal variant but reflects a severe, almost confluent perimacular dot and fleck retinopathy. This sign is useful diagnostically and also prognostically, since it is associated with early-onset renal failure.

The design, characteristics and predictors of mortality in the North of England Cellulitis Treatment Assessment (NECTA)

AIMS

Cellulitis is a common cause of acute medical admissions in UK hospitals. The factors that determine susceptibility to an acute admission or to mortality following hospital admission are poorly defined.

METHODS

We studied a retrospective cohort of 568 patients with a diagnosis of cellulitis between 1 January 2001 and 31 December 2003 in the north-east of England to see whether we could determine these factors. We collected data on the factors that were associated with acute hospital admissions and survival. We used a primary end-point of deaths within 1 year of admission for cellulitis.

RESULTS

The characteristics that identified patients at high risk of mortality were present in 39.9% of the cohort studied. The four most common of these characteristics were lower limb oedema 30.1% (95% CI: -26.0 to 34.1), ulceration 24% (95% CI: -20.2 to 27.8), previous myocardial infarction (MI) 19.9% (95% CI: -16.3 to 23.4) and blunt injury 18.7% (95% CI: -15.3 to 22.2). Significant predictors of mortality were: patient's age (p < 0.001), presence of penetrating injury (p < 0.001), previous MI (p < 0.001), presence of liver disease (p = 0.003), presence of lower limb oedema (p = 0.01) and long-term use of drugs that caused sodium and water retention (p < 0.001). Treatment with i.v. flucloxacillin was found to be a significant predictor of survival (odds ratio = 3.43, z =3.42. p < 0.001) at 360 days.

CONCLUSION

Our results show that cellulitis as a cause of an acute medical admission may present with a variety of clinical features. Some of these clinical features can be used to predict mortality within 360 days of an acute hospital admission.

The effect of the major components of Salvia Miltiorrhiza Bunge on bone marrow cells

Salvia Miltiorrhiza Bunge (SMB), a traditional Chinese medicinal herb, has been alleged to support bone healing. However, the effects of the isolated major components of SMB on osseous cells and their corresponding effective doses are still unclear. In the present study, the effects of three components of SMB, including tanshinone IIA (Ts), salvianolic acid B (salB) and protocatechuic aldehyde (Pca), on mesenchymal bone marrow cells with the potential for osteoblastic differentiation were investigated. Various concentrations of Ts, salB and Pca were added to a rat bone marrow cell culture. The total metabolic activity and differentiation of bone marrow cells were evaluated by a metabolic assay and alkaline phosphatase (ALP) activity, respectively. The morphology and number of cells was observed by phase contrast microscopy and fluorescent microscopy after propidium iodide staining, respectively. Ts suppressed the growth and differentiation of bone precursor cells. SalB exhibited a biphasic effect: the high concentration of 160 microg/mL significantly depressed the population of bone marrow cells, however, lower concentrations (3-80 microg/mL) enhanced the total metabolic activity and their ALP expression. Pca suppressed the bone marrow cell population in a dose-dependent manner. Therefore, SalB has the potential to ameliorate bone healing by stimulating both the total metabolic activity and ALP activity of osteoblastic cells. Aqueous extracts, which preferably contain salB over Pca and are free of Ts therefore are recommended for bone formation.

Prospective prediction of spontaneous but not recurrent autoimmune diabetes in the non-obese diabetic mouse

AIMS/HYPOTHESIS

Type 1 diabetes is a T cell-mediated autoimmune disease with a clinically silent prodrome, during which prediction and treatment of disease are theoretically possible. Using retrospective analysis, spontaneous disease in the non-obese diabetic (NOD) mouse has been correlated with islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)-reactive CD8+ T cells in the peripheral blood. In this study, we determined prospectively whether IGRP-reactive T cells in peripheral blood could predict disease occurrence. Since recurrent autoimmunity is an important contributor to transplant failure, we also determined whether failure of islet grafts (syngeneic and allogeneic) could be predicted by the presence of circulating autoreactive T cells.

MATERIALS AND METHODS

Peripheral blood samples were taken weekly from female NOD mice between the ages of 8 and 30 weeks and from NOD mice transplanted with NODscid islets. Peripheral blood cells and islet grafts were analysed for the presence of IGRP-reactive CD8+ T cells by flow cytometry.

RESULTS

Prospective analysis of peripheral blood IGRP-reactive T cells in the prediabetic period predicted disease development with a sensitivity of 100% and a specificity of 60%, resulting in positive and negative predictive values of 85 and 100%, respectively. Significant proportions of IGRP-reactive T cells were found in the grafts, but not in peripheral blood of NOD mice undergoing syngeneic and allogeneic rejection.

CONCLUSIONS/INTERPRETATION

The occurrence of spontaneous diabetes can be predicted prospectively by measuring peripheral blood autoreactive T cells. Rejection of syngeneic or allogeneic islets is associated with large populations of autoreactive CD8+ T cells within islets, suggesting that immunodominant autoreactive T cells during the prediabetic period are also responsible for autoimmune graft rejection.

A non-invasive system for assessment of aortic stiffness in clinical practice

Previously aortic stiffness is frequently assessed through pulse pressure and pulse wave velocity (PWV) measurements. However, these methods need aortic pressure obtained by catheterization. A new model has been developed to rapidly determine the aortic pressure profile and simultaneously calculate aortic stiffness. Comparison between the aortic pressure result obtained from this and catheterization data demonstrates good agreement, while this method is non-invasive. This totally non-invasive method should be useful in assessing arteriosclerotic disease in clinical setting.