Acute-on-chronic renal failure in the rat: functional compensation and hypoxia tolerance

BACKGROUND: We hypothesized that chronic renal parenchymal disease may predispose to acute renal failure (ARF), facilitating the induction of hypoxic medullary tubular injury. METHODS: To induce chronic renal parenchymal injury, rats underwent sham operation (control) or bilateral 50-min clamping of the renal artery [ischemia-reperfusion (IR)]. One or 3 months later, both groups were subjected to an ARF protocol, consisting of radiocontrast and the inhibition of prostaglandin and nitric oxide synthesis. Renal function and morphology were determined 24 h later. RESULTS: Chronic tubulointerstitial changes (fibrosis, atrophy and hypertrophy) in the IR group correlated with baseline tubular function, but glomerular function was preserved. Functional deterioration after the ARF protocol was only marginally more pronounced in the IR group, and the degree of medullary acute tubular necrosis (ATN) was unaffected by prior IR. The extent of both tubular necrosis and chronic tubulointerstitial changes independently predicted the acute decline in renal function. Immunostaining of IR kidneys disclosed critically low medullary pO2 (determined by pimonidazole adducts), regional hypoxic cell response (hypoxia-inducible factors) and upregulation of endothelin-B receptors. CONCLUSIONS: Compensatory changes result in normal plasma creatinine 1 and 3 months after IR, despite diminished tubular function. Preexisting renal disease only marginally predisposes to ARF, and the extent of ATN is not significantly enhanced. These findings illustrate the complex interaction between chronic and acute renal injury and dysfunction and parallel the difficulty of their assessment in the clinical practice. Adaptive cellular responses to chronic hypoxia in conjunction with parenchymal loss and decreased oxygen demand might alleviate acute hypoxic injury.     

Thyrotrophin-responsive adenylate cyclase activity in thyroid toxic adenoma.

The adenylate cyclase system was studied in hyperfunctioning autonomous nodules in comparison with normal thyroid tissue. The basal, TSH- and NaF-stimulated adenylate cyclase activities were tested in purified plasma membrane preparations. Basal enzyme activity in membranes from hyperfunctioning nodules was variable and the response to TSH was either normal, low or absent. The present study demonstrates that an intact adenylate cyclase activity, hyporesponsive to TSH, may exist in the cell membrane of the adenoma.     

Action of gold thioglucose on pericapillary structures in the ventromedial hypothalamus.

The administration of GTG to mice leads to death of all structures in a circumscribed area of the VMH as a result of loss of blood circulation. The loss of circulation is due to damage by GTG of neural processes adjacent to some of the capillaries in this area; damage to these processes leads to abnormal capillary permeability. Pericapillary damage occurs under conditions where capillary damage and consequent necrosis are prevented. Abnormal capillary permeability appears to follow release of a vasoactive substance from the damaged neural processes. Damage to the pericapillary neural processes by GTG is insulin-dependent and is counteracted by glucocorticoids.     

Double-blind, crossover, placebo-controlled clinical trial with L-acetylcarnitine in patients with degenerative cerebellar ataxia

Despite the different genetic defects underlying degenerative ataxias, it has been suggested that mitochondrial energy production and antioxidative metabolism dysfunction may be common biochemical alterations related to these diseases. Acetylcarnitine, a cholinomimetic substance, is involved in oxidative metabolism and is a potential source of acetyl groups for the synthesis of acetylcholine in the mammalian brain. To determine whether treatment with L-acetylcarnitine may improve some clinical conditions of patients with ataxia, a double-blind crossover study with L-acetylcarnitine was performed in 24 patients with degenerative cerebellar diseases. Patients were selected from an ongoing prospective follow-up study at the Department of Neurology at the University of Florence, Italy. Each treatment phase with L-acetylcarnitine or placebo lasted 6 months, after which patients were crossed over to the other treatment phase. Ataxia was documented and quantified with use of a clinical score. After the trial, we observed a statistically significant improvement of some symptoms and a slow progression of the disease in both groups of patients.     

<Superscript>99m</Superscript>Tc sestamibi myocardial perfusion scintigraphy with the novel use of metamizol for the detection of perfusion reversibility

PURPOSE: This study aims to investigate whether induction with metamizol, an analgesic-antipyretic drug having spasmolitic activity, could be used to increase the detectability of ischemic/jeopardized myocardium during MPS (myocardial perfusion scintigraphy). MATERIALS AND METHODS: Metamizol-enhanced rest MPS (45 min after administration of 1 g metamizol orally, 740 MBq (99m)Tc sestamibi was injected, MPS was acquired 45 min later) was performed in 21 patients who had perfusion defects on their previous stress-rest (99m)Tc sestamibi MPS. Blood pressure was monitored at 15-min intervals. Stress, rest, metamizol-rest MPS images were interpreted on the model of 20 segments using a visual uptake score (VUS; 0 = normal, 1 = mild, 2 = moderate, 3 = significant decreases, 4 = no uptake). (99m)Tc sestamibi uptake ratios (MIBI-UR; mean counts in the region of the perfusion defect/mean counts in the region of the normal-perfused wall) were obtained on each MPS and compared with each other. Average MIBI-UR in each scintigraphic examination was calculated. MPS were compared with coronary angiography results. RESULTS: VUS and MIBI-UR results showed that metamizol-rest MPS displayed the defect reversibility better than rest MPS. Of the 14 segments with fixed perfusion defects on stress-rest MPS, 8 showed improvement of perfusion after metamizol induction. In 33 segments, lesion reversibility was better delineated on metamizol-rest MPS. Metamizol-induced sestamibi uptake was significantly higher (p < 0.001) than stress/baseline rest examinations as calculated by the MIBI-UR. Blood pressure remained unaltered. Coronary angiography results were in concordance with metamizol induced MPS. CONCLUSIONS: Metamizol-enhanced rest MPS increases detectability of ischemic/viable myocardium during MPS. Metamizol should be discontinued like nitrates before stress MPS since it may mask the visualization of ischemic perfusion defects.     

Risk factors related to intention to breastfeed, early weaning and suboptimal duration of breastfeeding

AIM: To identify maternal and infantile factors affecting intention to breastfeed, early weaning and duration of breastfeeding. DESIGN/SUBJECTS: In a prospective cohort study, 1049 mothers were interviewed after delivery and at 1, 3, 6, 9 and 12 months post-partum. RESULTS: Of 1049 mothers, 942 (89.7%) intended to breastfeed. Negative attitude was associated with lack of breastfeeding previous offspring, multiparity, admission to neonatal ward, tobacco use, prematurity and male gender (OR: 10.1, 2.67, 3.02, 2.63, 2.40 and 1.54, respectively). Six hundred and twenty-three mothers (60.7%) were breastfeeding at month 1. Early weaning was associated with lack of breastfeeding previous offspring, tobacco use, prematurity, admission to neonatal ward, caesarean section (OR: 12.3, 3.39, 2.33, 2.22, 1.34), low education (p < 0.0001) and young age (p = 0.034). Factors negatively affecting total duration of breastfeeding included lack of breastfeeding previous offspring (3.91 vs. 16.2 weeks, p < 0.001), tobacco use (6.78 vs. 15.9 weeks, p < 0.001), low education (p < 0.001), early re-employment (12.5 vs. 15.1 weeks, p < 0.01) and prematurity (p < 0.005). CONCLUSION: Maternal negative attitude, tobacco use and early re-employment are factors negatively affecting breastfeeding that can be liable to intervention. All health professionals involved in perinatal medicine share a part of responsibility in sustaining breastfeeding, particularly in high-risk groups of mothers.     

European ST80 community-associated methicillin-resistant Staphylococcus aureus orbital cellulitis in a neonate

Background

To report atypical features on Spectral domain optical coherence tomography (SD-OCT) in a case of non-familial pure adult nanophthalmos.

Case presentation

A 39?year old male hyperope was found to have biometric and fundus findings typical of nanophthalmos. The additional atypical features included serous pigment epithelial detachment (PED) in right eye and a cuff of subretinal fluid with underlying yellow deposits along superotemporal arcade in the left eye. Fundus flourescein angiogram showed hyperfluorescence due to window defect, dye pooling due to serous PED in right eye and leak superior to disc in right eye and superotemporally in left eye. Cirrus-SD OCT horizontal line scan passing through the fovea showed extensive inner limiting membrane corrugations causing distorted foveal contour in both eyes. A large juxtafoveal serous PED and a small extrafoval PED were seen with folds in the retinal pigment epithelium (RPE)-choriocapillary layer in the right eye.

Conclusion

Structural disruptions in the RPE-choriocapillary complex in the form of folds or juxtafoveal serous PED and RPE folds can be atypical features of nanophthalmic macula better discerned on high resolution OCT.