Neurovascular hypoxia after mild traumatic brain injury in juvenile mice correlates with heart-brain dysfunctions in adulthood

AIM

Retrospective studies suggest that mild traumatic brain injury (mTBI) in pediatric patients may lead to an increased risk of cardiac events. However, the exact functional and temporal dynamics and the associations between heart and brain pathophysiological trajectories are not understood.

METHODS

A single impact to the left somatosensory cortical area of the intact skull was performed on juvenile mice (17 days postnatal). Cerebral 3D photoacoustic imaging was used to measure the oxygen saturation (sO₂ ) in the impacted area 4 h after mTBI followed by 2D and 4D echocardiography at days 7, 30, 90, and 190 post-impact. At 8 months, we performed a dobutamine stress test to evaluate cardiac function. Lastly, behavioral analyses were conducted 1 year after initial injury.

RESULTS

We report a rapid and transient decrease in cerebrovascular sO₂ and increased hemoglobin in the impacted left brain cortex. Cardiac analyses showed long-term diastolic dysfunction and a diminished systolic strain response under stress in the mTBI group. At the molecular level, cardiac T-p38MAPK and troponin I expression was pathologic modified post-mTBI. We found linear correlations between brain sO₂ measured immediately post-mTBI and long-term cardiac strain after 8 months. We report that initial cerebrovascular hypoxia and chronic cardiac dysfunction correlated with long-term behavioral changes hinting at anxiety-like and memory maladaptation.

CONCLUSION

Experimental juvenile mTBI induces time-dependent cardiac dysfunction that corresponds to the initial neurovascular sO₂ dip and is associated with long-term behavioral modifications. These imaging biomarkers of the heart-brain axis could be applied to improve clinical pediatric mTBI management.

Escherichia coli morphological changes and lipid A removal induced by reduced pressure nitrogen afterglow exposure

Lipid A is a major hydrophobic component of lipopolysaccharides (endotoxin) present in the membrane of most Gram-negative bacteria, and the major responsible for the bioactivity and toxicity of the endotoxin. Previous studies have demonstrated that the late afterglow region of flowing post-discharges at reduced pressure (1-20 Torr) can be used for the sterilization of surfaces and of the reusable medical instrumentation. In the present paper, we show that the antibacterial activity of a pure nitrogen afterglow can essentially be attributed to the large concentrations of nitrogen atoms present in the treatment area and not to the UV radiation of the afterglow. In parallel, the time variation of the inactivation efficiency quantified by the log reduction of the initial Escherichia coli (E. coli) population is correlated with morphologic changes observed on the bacteria by scanning electron microscopy (SEM) for increasing afterglow exposure times. The effect of the afterglow exposure is also studied on pure lipid A and on lipid A extracted from exposed E. coli bacteria. We report that more than 60% of lipid A (pure or bacteria-extracted) are lost with the used operating conditions (nitrogen flow QN2 = 1 standard liter per minute (slpm), pressure p = 5 Torr, microwave injected power PMW = 200 W, exposure time: 40 minutes). The afterglow exposure also results in a reduction of the lipid A proinflammatory activity, assessed by the net decrease of the redox-sensitive NFκB transcription factor nuclear translocation in murine aortic endothelial cells stimulated with control vs afterglow-treated (pure and extracted) lipid A. Altogether these results point out the ability of reduced pressure nitrogen afterglows to neutralize the cytotoxic components in Gram-negative bacteria.

Annexin II-dependent actin remodelling evoked by hydrogen peroxide requires the metalloproteinase/sphingolipid pathway

Actin remodeling is a dynamic process associated with cell shape modification occurring during cell cycle and proliferation. Oxidative stress plays a role in actin reorganization via various systems including p38MAPK. Beside, the mitogenic response evoked by hydrogen peroxide (H₂O₂) in fibroblasts and smooth muscle cells (SMC) involves the metalloproteinase (MMPs)/sphingomyelinase 2 (nSMase2) signaling pathway. The aim of this work was to investigate whether this system plays a role in actin remodeling induced by H₂O₂.

Low H₂O₂ dose (5 µM) rapidly triggered a signaling cascade leading to nSMase2 activation, src and annexin 2 (AnxA2) phosphorylation, and actin remodeling, in fibroblasts and SMC. These events were blocked by pharmacological inhibitors of MMPs (Ro28-2653) and p38MAPK (SB203580), and were lacking in MMP2^−/− and in nSMase2-mutant (fro) fibroblasts. Likewise, H₂O₂ was unable to induce actin remodeling in fro and MMP2^−/− fibroblasts or in cells pretreated with p38MAPK, or MMP inhibitors. Finally we show that nSMase2 activation by H₂O₂, depends on MMP2 and p38MAPK, and is required for the src-dependent phosphorylation of AnxA2, and actin remodeling.

Taken together, these findings indicate for the first time that AnxA2 phosphorylation and actin remodeling evoked by oxidative stress depend on the sphingolipid pathway, via MMP2 and p38MAPK.

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Low concentration of H₂O₂ activates matrix metalloproteinases MMP-2.

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MMP-2 activates p38MAPK, type 2 neutral sphingomyelinase.

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This signaling pathway induces annexin II phosphorylation via src.

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This pathway is involved in actin remodeling due to H₂O₂ stimulation.

Protein disulfide isomerase modification and inhibition contribute to ER stress and apoptosis induced by oxidized low density lipoproteins

AIMS

Protein disulfide isomerase (PDI) is an abundant endoplasmic reticulum (ER)-resident chaperone and oxidoreductase that catalyzes formation and rearrangement (isomerization) of disulfide bonds, thereby participating in protein folding. PDI modification by nitrosative stress is known to increase protein misfolding, ER stress, and neuronal apoptosis. As LDL oxidation and ER stress may play a role in atherogenesis, this work was designed to investigate whether PDI was inactivated by oxLDLs, thereby participating in oxLDL-induced ER stress and apoptosis.

RESULTS

Preincubation of human endothelial HMEC-1 and of macrophagic U937 cells with toxic concentration of oxLDLs induced PDI inhibition and modification, as assessed by 4-HNE-PDI adducts formation. PDI inhibition by bacitracin potentiated ER stress (increased mRNA expression of CHOP and sXBP1) and apoptosis induced by oxLDLs. In contrast, increased PDI activity by overexpression of an active wild-type PDI was associated with reduced oxLDL-induced ER stress and toxicity, whereas the overexpression of a mutant inactive form was not protective. These effects on PDI were mimicked by exogenous 4-HNE and prevented by the carbonyl-scavengers N-acetylcysteine and pyridoxamine, which reduced CHOP expression and toxicity by oxLDLs. Interestingly, 4-HNE-modified PDI was detected in the lipid-rich areas of human advanced atherosclerotic lesions. Innovation and

CONCLUSIONS

PDI modification by oxLDLs or by reactive carbonyls inhibits its enzymatic activity and potentiates both ER stress and apoptosis by oxLDLs. PDI modification by lipid peroxidation products in atherosclerotic lesions suggests that a loss of function of PDI may occur in vivo, and may contribute to local ER stress, apoptosis, and plaque progression.

Secular trend and intrapopulational variation in age at menopause in Spanish women

Menopause is associated with the general ageing process and marks the end of follicular depletion, a process that begins in the intrauterine stage and lasts throughout the lifetime of women until their reproductive senescence. Controversy persists about whether the age at menopause is sensitive to the ecological determinants prevailing during the lifecycle or whether it has a predominantly genetic component that would allow groups of women to be characterized with respect to particular menstrual characteristics manifested throughout their fertile life. By contrast, there is a definite secular trend in age at menarche in populations that have registered improvements in their environment: sexual maturation is closely associated with the general processes of growth and development. These aspects were analysed in a sample of Spanish women, mothers and daughters, born between 1883 and 1941. The results show (a) indications--although not conclusive--of a secular trend in the age at menopause, (b) a possible association between the age at menopause of mothers and their daughters, and (c) an association at the individual level between age at menarche, particular characteristics of ovarian function (fetal loss) and age at menopause. The reproductive ageing process therefore seems to result from the expression of the influence of ecological conditions in which the lifecycle of the women develops and of a degree of heritability that affects not only the age at menopause but also a range of characteristics of ovarian function.

Lifetime dietary change and its relation to increase in weight in Spanish women

INTRODUCTION

Changes in dietary patterns and a decrease in physical activity have occurred in Western countries. These are factors in the variation in body composition observed in populations, characterized by a progressive accumulation of fat with age and a consequent increase in the risk of suffering from common chronic illnesses such as obesity, cardiovascular disease and cancer.

OBJECTIVE

To investigate weight gain throughout the life-cycle and its relation to modifications in dietary patterns, analyzing the causes of these modifications and their implications for patterns of adult overweight and obesity.

DESIGN

Cross-sectional sample of Spanish women from a socio-economically disadvantaged class.

SUBJECTS

1037 healthy perimenopausal women (age: 45-65 y).

MEASUREMENTS

Juvenile body mass index (BMI), current BMI, food frequency questionnaire, retrospective food habits.

RESULTS AND CONCLUSIONS

Of these women, 48.8% had changed their dietary habits during their lifetime. A change in diet due to migration or marriage occurred at approximately 20 years of age and was characterized by an increased frequency of consumption of foods rich in protein and complex carbohydrates, while a change due to illness occurred at around 50 years of age and was characterized by a decrease in the consumption of these types of food. The change in dietary behavior due to migration was associated with weight gain. Weight gain was also inversely associated with BMI during youth; women who in their youth had a BMI<18.5 kg/m2 gained an average of 21.4 kg, compared with those with a BMI>27 kg/m2 in their youth, who gained an average of 5.4 kg. International Journal of Obesity (2000)24, 14-19

Characteristics of menstrual cycles in Moroccan girls: prevalence of dysfunctions and associated behaviours

Population studies on normal and dysfunctional characteristics of menstrual cycles are scarce for western populations and practically non-existent for non-western ones. Recent data suggest that the type of menstrual cycle can be relevant for later gynaecological problems in several ways. The type of menstrual cycle is related to menarcheal age in a way that those with early maturation show more menstrual disorders which are the largest diagnosis category accounting for hysterectomies in adult women. On the other hand menstrual pain is often cited as the main single cause of school absenteeism among adolescent girls. The aim of this study is to describe characteristics of menstrual cycles, prevalence of main dysfunctions and their relationship to the age of maturity. The sample comprises 495 adolescent girls from Marrakech (Morocco) aged 12-19 years. At 13 years, 40% of these girls had reached menarche. The median age at menarche is 13.04. The prevalences of abdominal pain, premenstrual symptoms and irregularity are 69.60, 51.20 and 23.03 respectively. Abdominal pain is significantly more frequent in girls with early menarche.

[Acute renal failure in the allogeneic transplantation of hemopoietic progenitors. The clinical characteristics in a series of 92 patients]

BACKGROUND

Analysis of clinical characteristics of acute renal failure (ARF) after allogeneic bone marrow transplantation (BMT).

PATIENTS AND METHODS

Analysis of 92 patients who developed ARF of 260 patients following BMT.

RESULTS

ARF incidence was 35.4%. Sixty three percent of ARF occurred before day 20 after BMT. Duration of ARF was less of 10 days in 72.8%. ARF was non oliguric in the 80.4% of cases. Most common ARF etiologies were: multifactorial (37%), nephrotoxicity (NPH) (33.7%) and veno-occlusive disease of the liver (VOD) (14.1%). ARF secondary to VOD was the most severe: and the longest, where the secondary to NPH was less lever and shorter. Hemodialysis (HD) was necessary in 22.8% of ARF. Mortality in ARF group was 45.6%, higher in HD group (80.9%) than in non-HD group (35.2%) (p < 0.0002).

CONCLUSIONS

ARF is a frequent complication following BMT. It occurs early, has short duration, is non oliguric, mainly hemodynamic and carries a whose prognosis.

Nephroprotective effect of cilastatin in allogeneic bone marrow transplantation. Results from a retrospective analysis

Cilastatin, an inhibitor of the tubular brush border enzyme dehydropeptidase-I, is added in a fixed combination to imipenem. Cilastatin has been demonstrated in different animal models and in one clinical trial, to reduce the nephrotoxicity associated with cyclosporin A. To evaluate a possible nephroprotective effect of cilastatin following allogeneic BMT we conducted a retrospective analysis of 104 patients transplanted in our BMT Unit from January 1991 to January 1995. Imipenem/cilastatin (I/C) was used in a non-randomized manner in 64 patients during this period. Acute renal failure (ARF) was diagnosed in 32 patients (30%). ARF was not associated with gender, sepsis, conditioning regimen, underlying disease, bilirubin, or age. VOD occurred in 12/32 (37.5%) of patients with ARF whereas it occurred in only 7/72 (9.7%) of patients without ARF (P < 0.0007). ARF was not correlated with use of aminoglycosides, vancomycin, ciprofloxacine, ceftazidime or amphotericin-B. However, 13 patients of 64 exposed to I/C (20.3%) developed ARF vs 19 of 40 patients (47.5%) who were not exposed to I/C (P < 0.003; OR 0.28). Stratified analysis and multiple logistic regression confirmed the I/C nephroprotective action. The mean cyclosporin A levels in the I/C group were significantly decreased (208.6 +/- 64.9) vs the non-I/C group (265 +/- 118). We conclude that these results suggest I/C may counteract acute cyclosporin A nephrotoxicity following BMT and further prospective clinical trials are needed to confirm if routine administration of cilastatine confers benefit in the BMT setting.

Influence of body mass index and slimming habits on menstrual pain and cycle irregularity

Using a cross-sectional sample of 1147 urban adolescents, aged between 14 and 20 years, the variability of some menstrual cycle indicators was related to weight loss. Nearly 40% of the adolescents tried to lose weight and the results showed that attempting to lose weight is significantly associated with increased prevalence of menstrual irregularity and menstrual pain. This finding is independent of body mass index.

Microscopic polyangiitis. A systemic vasculitis with a positive P-ANCA

A young girl presented with a purpuric rash on lower limbs, fever, eosinophilia, peripheral neuropathy and progressive renal insufficiency. She developed vesicles, purpuric macules and papules on the head, several nodules on the palmar sides of hands and fingers, splinter haemorrhages, and a disfiguring, facial oedema. A renal biopsy specimen disclosed a focal and segmental necrotizing glomerulonephritis with crescents. Peripheral ANCA with antimyeloperoxidase specificity [P-ANCA (MPO)] was positive and cytoplasmic ANCA with PR3 specificity was negative. Treatment with prednisone and cyclophosphamide was started with a good clinical response, stabilization of renal insufficiency and disappearance of P-ANCA (MPO). Our case fulfils the diagnostic criteria for microscopic polyangiitis (microscopic polyarteritis, MPA), namely a segmental necrotizing and crescentic glomerulonephritis associated with extrarenal vasculitis involving small-sized vessels, without granulomas or asthma. This is a rare disease, which has a poor prognosis in the absence of aggressive therapy, and is infrequently reported in dermatological journals.

Acute renal failure in patients following bone marrow transplantation: prevalence, risk factors and outcome

To assess the prevalence, risk factors, clinical causes and outcome of acute renal failure (ARF) following bone marrow transplantation (BMT), a retrospective analysis of 275 patients was undertaken. ARF was diagnosed in 72 patients (26%) and occurred in 81.9% within the first month. The three main clinical causes were multifactorial (36%), nephrotoxic (29%), and veno-occlusive disease of the liver (VOD) 15%. The prevalence was higher in allogeneic BMT (36%) than in autologous BMT (6.5%). Risk factors related to the development of ARF wee preexisting VOD and age older than 25 years. Logistic regression in allogeneic BMT confirmed this association (VOD, odds ratio 3.8; age offer than 25, odds ratio 1.9). Underlying disease, graft-versus-host disease, sepsis, conditioning therapy, and sex were not associated with ARF. Seventeen cases of ARF required hemodialysis (24%) mainly in association with VOD (70.5%). The overall morality from ARF was 45.8%, the dialyzed group having the highest mortality (88%). Survival in the ARF group was continuously worse up to 3 months and the actuarial survival at 10 years was 29.7 versus 53.2%. We conclude that ARF is a common complication mainly in allogeneic BMT and carries a grave prognosis. VOD and age were risk factors for ARF.

Physiological maturation, reproductive patterns, and female fecundability in a traditional Moroccan population (Amizmiz, Marrakech)

The interaction between age at menarche, adolescent motherhood, and subfecundity were evaluated in 496 Moroccan women 25-54 years of age from the province of Marrakech. Since this population is characterized by later sexual maturation and early marriage, significantly increased subfecundity, measured by the waiting time to first live birth and the incidence of fetal loss, was expected. Menstrual age was defined as the difference between age at marriage and age at menarche. Social access to reproduction was conditioned by age at menarche: early maturers married at a younger age, while late maturers had a significantly shorter menstrual age despite the fact that married at a significantly older age. Although there was a tendency for late maturers to have longer waiting times and more fetal loss, there were no significant differences for either variable according to menarcheal age. Women with a shorter menstrual age became pregnant within the first year after marriage significantly less frequently than women with a greater menstrual age, but did not experience a greater occurrence of fetal loss during their reproductive life. The results indirectly support the hypothesis that the regularity of ovarian function is similar among populations independent of the timing of menarche. © 1993 Wiley-Liss, Inc.

The pattern of reproductive life in a Berber population of Morocco

Reproductive patterns were studied from data collected in 1,450 Berber households in the province of Marrakesh, Morocco in 1984. Women aged 45-49 years had a mean of 8.9 pregnancies to achieve 5.7 living children. Social influences on fertility rates show the importance of tradition, particularly through time-dependent variables such as age at marriage, waiting time to first birth, interbirth intervals, and duration of breastfeeding. Birth control does not appear to affect the tempo of fertility; rather, its main use is to bring the reproductive period to a close. The comparison of two subsamples of women separated by a 25-year interval indicates an actual acceleration of the tempo of fertility by the reduction of waiting time to first birth and of interbirth intervals. The supposed ongoing process of demographic transition is not clearly observed in this population.

Development of systemic lupus erythematosus in a patient on hemodialysis

A case of systemic lupus erythematosus (SLE) that developed 2 years after beginning hemodialysis is reported. The patient had not been given any drug implicated in the production of SLE. She had been treated with deferoxamine, an in vitro inhibitory of DNA synthesis. The difficulty of the diagnosis is emphasized. Clinical improvement after prednisone treatment was impressive. SLE may appear even in patients receiving hemodialysis, despite immunological depression derived from chronic uremia.

Renal failure in temporal arteritis

We report a case of biopsy-proven temporal arteritis and polymyalgia rheumatica with improved clinical symptoms with steroid treatment but with subsequent renal failure while on steroids. Kidney biopsy showed focal segmental necrotizing glomerulonephritis with crescents and small-vessel vasculitis. Treatment with methylprednisolone and cyclophosphamide achieved normalization of renal function. We emphasize the importance of kidney biopsy because of its therapeutic implications. The previous literature concerning renal disease in temporal arteritis is discussed.

Acid-base derangements during sorbent regenerative hemodialysis in mechanically ventilated patients

OBJECTIVE

To assess acid-base derangements during sorbent regenerative hemodialysis in mechanically ventilated patients.

DESIGN

Consecutive case series; prospective study.

SETTING

An ICU in a university hospital.

PATIENTS

Seven patients undergoing hemodialysis for acute renal failure who required mechanical ventilation for acute respiratory failure.

INTERVENTIONS

Pulmonary and systemic hemodynamics, pH, and gas tensions in dialysate, arterial and mixed venous blood, and blood entering and leaving the dialyzer, were measured before, during, and after hemodialysis.

MEASUREMENTS AND MAIN RESULTS

During the first 2 hrs of hemodialysis, dialysate pH decreased from 6.91 +/- 0.14 to 6.06 +/- 0.37 and PCO2 increased to 437 +/- 111 torr (58.2 +/- 14.8 kPa). Simultaneously, the patients lost bicarbonate into the bath. As a result, pHa decreased from 7.38 +/- 0.02 to 7.31 +/- 0.02. At the end of dialysis, pHa returned to normal.

CONCLUSION

Sorbent hemodialysis in mechanically ventilated patients is accompanied by acidosis that may contribute to hemodynamic instability.

The role of urinary PGE2 and renin-angiotensin-aldosterone system in the pathogenesis of essential hypertension

In a group of 26 patients diagnosed as essential hypertensive (EH) and in a control group (CG) of 27 normotensive volunteers the urinary excretion of PGE2, plasma renin activity (PRA) and plasma aldosterone were measured. EH patients were classified into normoreninemic (NREH) (n = 21) and hyporeninemic (LREH) (n = 5) by the response of PRA to the combined stimuli of ambulation and furosemide. Urinary PGE2 excretion was higher in NREH than in CG (p less than 0.05) while LREH showed values lower than in CG (p less than 0.001). Plasma aldosterone levels were similar in the three groups. In CG and EH patients PRA and urinary PGE2 were closely related (CG r = 0.516, p less than 0.05, EH patients r = 0.674, p less than 0.001). Indomethacin administration induced a decrease of PGE2 in both CG (n = 8) and NREH (n = 8) (p less than 0.01). In contrast, indomethacin induced no changes in PGE2 excretion of LREH (n = 5). Furthermore in the group of patients with NREH indomethacin induced a significant increase in blood pressure (p less than 0.01) and body weight (p less than 0.01) while glomerular filtration rate, 24 hour natriuresis PRA and plasma aldosterone decreased (p less than 0.01). On the contrary, in LREH indomethacin did not alter any of the parameters measured. These results indicate that LREH and NREH may be regarded as two different populations distinguishable not only by different secretion of PRA but also by different excretion of PGE2 in urine and by their characteristic response to indomethacin.

Role of renal prostaglandin E2 in chronic renal disease hypertension

The role played by renal prostaglandin E2 in the maintenance of hypertension in chronic renal disease has been investigated through studying the response of body weight, blood pressure, glomerular filtration rate (GFR), 24-hour natriuresis, plasma renin activity (PRA), plasma aldosterone and urinary PGE2 excretion to the administration of indomethacin (2mg/kg daily, during 3 days). A group of 37 patients diagnosed as having chronic renal parenchymatous disease with creatinine clearance above 25 ml/min was included in the study. 21 of them were hypertensive (BP greater than 160/95). 27 normotensive volunteers were also studied and considered as the control group. The initial study disclosed similar levels of PGE2, PRA and plasma aldosterone in volunteers, normotensive patients and hypertensive patients, although the sodium intake was lower in the last two groups. A positive correlation between PRA and urinary PGE2 was found both in normotensive (r = 0.507, p less than 0.01) and in hypertensive patients (r = 0.609, p less than 0.01). The administration of indomethacin induced a diminution of PRA, plasma aldosterone and urinary PGE2 levels together with an increase in diastolic blood pressure (p less than 0.05-0.01) in both volunteers and patients. The remaining parameters measured did not change in volunteers or in normotensive patients. On the contrary, in hypertensive patients, during indomethacin administration, lower values of creatinine clearance (p less than 0.005) and 24-hour natriuresis (p less than 0.05) together with an increase in body weight (p less than 0.01) were observed. These results point to the existence of a protective role of renal prostaglandin E2 upon renal function when hypertension appears in the course of chronic renal parenchymatous disease.