Renal blood flow measurement by positron emission tomography using 15O-labeled water

BACKGROUND: Only few noninvasive methods have the potential to quantitate renal blood flow (RBF) in humans. Positron emission tomography (PET) is a clinical imaging method that can be used to measure the tissue blood flow noninvasively. The purpose of this study was to validate PET measurement of RBF using 15O-labeled water (H215O), a tracer that allows repeated measurements at short time intervals. METHODS: RBF was measured in six pigs by PET and by radioactive microspheres (MS). Three measurements were performed in each pig at baseline (BL), during vascular expansion and dopamine infusion (DA; 20 microg. kg-1. min-1 intravenously), and during angiotensin II (Ang II) infusion (50 ng. kg-1. min-1 intravenously). RBF was estimated from aortic and renal tracer kinetics using a model adapted from the blood flow model described by Kety and Smith. RESULTS: PET and MS values correlated strongly (y = 0.79x + 42, r = 0.93, P < 0.0001) over the RBF range from 100 to 500 mL. min-1. 100 g-1. Pharmacologically induced changes were significant and were measured equally well by PET and MS: 38 and 39%, respectively, below BL (P < 0.005 and P < 0.05) under Ang II, and 47 and 48%, respectively, above BL (P < 0.005 and P < 0.01) under DA. A Bland and Altman representation showed a low average difference of -17 +/- 45 mL. min-1. 100 g-1 (mean +/- SD). CONCLUSION: To our knowledge, this study provides the first validation of RBF measurement by PET using H215O over a large range of RBF values (100 to 500 mL. min-1. 100 g-1), which correspond to RBF values in both healthy subjects and in patients suffering from chronic renal failure.     

Spatial encoding properties of subnucleus reticularis dorsalis neurons in the rat medulla

Denervation of the synergists of the medial gastrocnemius (MG) muscle in the cat hind leg results in a progressive increase in the magnitude of burst activity in the MG muscle during walking. The increase in burst magnitude is associated with an increase in the slope of the relationship between the magnitude of individual MG bursts and the amplitude of ankle flexion during stance. This finding is consistent with the hypothesis that the increase in MG burst magnitude is due to an increase in gain of reflex pathways reinforcing the activation of MG. The increase in slope is use-dependent since it was not observed when the leg was released from a cast that immobilized the leg for 6 days.     

Pulmonary edema in meningococcal septicemia associated with reduced epithelial chloride transport.

OBJECTIVES: To test the hypothesis that meningococcal septicemia-related pulmonary edema is associated with a systemic abnormality of epithelial sodium and chloride transport and to investigate an association with hormones regulating Na transport. DESIGN: Prospective observational study. SETTING: The 24-bed pediatric intensive care unit and pediatric wards of Royal Liverpool Children's Hospital. PATIENTS: Consecutive children admitted to the pediatric intensive care unit and pediatric wards with a diagnosis of meningococcal septicemia and children (controls) with noninfectious critical illness receiving ventilatory support in the pediatric intensive care unit. MEASUREMENTS AND MAIN RESULTS: We measured sweat and saliva electrolytes, renal electrolyte excretion, nasal potential difference, and aldosterone, thyroxine, and cortisol levels. Pulmonary edema was diagnosed by chest radiography and its severity quantified by calculation of ventilation index at admission and duration of mechanical ventilation. We recruited 17 patients with severe meningococcal septicemia (nine patients with pulmonary edema), 14 patients with mild meningococcal septicemia, and 20 controls. Sweat and saliva Na and Cl concentrations and renal Na excretion were significantly (p < .05) higher in patients with pulmonary edema compared with controls. Nasal potential difference and amiloride response in patients with pulmonary edema were not significantly different to controls, but response to a low Cl solution was reduced in the nasal airway of patients with pulmonary edema (p < .05). Sweat and saliva chloride concentrations correlated significantly and better with ventilation index and duration of ventilation than sodium concentrations. Aldosterone, thyroxine, and cortisol levels were not significantly different between groups. CONCLUSIONS: We have confirmed that meningococcal septicemia-related pulmonary edema is associated with reduced systemic sodium and chloride transport. Features of reduced Cl transport were most closely associated with markers of respiratory compromise, and this was supported by the reduced chloride channel function detected on nasal potential difference measurement.     

Neuroimaging findings in infantile GM1 gangliosidosis

GM1 gangliosidosis is an autosomal recessive glycosphingolipid storage disease caused by defects in the enzyme beta-galactosidase. Three clinical forms (infantile-, juvenile-, and adult-onset) of the disease are recognized. Patients with infantile GM1 gangliosidosis present at birth or shortly thereafter with somatic and bony changes, followed by severe neurological deterioration ultimately leading to death within the first 2 years of life. We present the brain CT, MRI and MR spectroscopy (MRS) findings in a 17-month-old Turkish girl with infantile GM1 gangliosidosis. Neuroimaging findings in patients with infantile GM1 gangliosidosis have been reported only in a few cases. In this study, MRS of the thalamus was performed to study the metabolic changes in GM1 gangliosidosis. We showed a a decreased NAA/Cr ration and an increased Cho/Cr ratio. To our knowledge, this is the first report of magnetic resonance spectroscopy findings in type-1 GM1 gangliosidosis.     

Spinal arachnoiditis leading to recurrent reversible myelopathy: A case report

Context: A patient followed in the outpatient spinal cord injury support clinic at a VA Medical Center with a prior remote history of a gunshot wound to the back and multiple prior myelograms presented with a recurrent waxing and waning weakness of the left lower extremity and intermittent incontinence of bowel and bladder.Findings: During the evaluation, the patient experienced an immediate albeit temporary improvement in symptoms after a diagnostic lumbar puncture performed for CT myelogram. The symptoms of myelopathy reoccurred several weeks, but then the patient had a similar experience with rapid improvement in symptoms after an accidental fall down a flight of steps. Subsequently, the foot weakness and incontinence returned one week later. The patient ultimately developed permanent improvement in signs and symptoms after surgical intervention which included intradural lysis of adhesions, incision of the arachnoid membrane and resection of a cystic lesion.Clinical relevance: Patients who experience unexpected, albeit transient improvement in myelopathic symptoms who are known or suspected to have arachnoiditis should be evaluated for surgically remediable lesions. Remediation of these lesions can potentially improve long term outcome.     

Antioxidant,anticholinesterase and tyrosinase inhibition activities,and fatty acids of Crocus mathewii – A forgotten endemic angiosperm of Turkey

Context We report the first ever chemical/biochemical study on Crocus mathewii Kerndorff (Iridaceae) – a Turkish endemic angiosperm. This plant has never been explored for its phytochemistry and bioactivities.

Objective This study explores C. mathewii corm and aerial parts for the chemical and biological properties of hexane, ethyl acetate, methanol and water fractions of the extracts.

Material and methods Plant material (20 g) was extracted by methanol (250?mL?×?5, 3 days each) and fractioned into hexane, ethyl acetate, methanol and water. All fractions were subjected to β-carotene–linoleic acid, DPPH^·, ABTS^·+, CUPRAC, metal chelating and tyrosinase inhibition activities. Hexane fractions were submitted to GC–MS analysis.

Results Ethyl acetate fractions showed excellent IC₅₀ values in DPPH^· (aerial 36.21?±?0.76 and corm 33.87?±?0.02?mg/L) and ABTS^·+ (aerial 33.01?±?0.79 and bulb 27.87?±?0.33?mg/L); higher than the IC₅₀ of the standard α-tocopherol (DPPH 116.25?±?1.97; ABTS 52.64?±?0.37?mg/L), higher than BHA in DPPH (57.31?±?0.25?mg/L), but slightly lower in ABTS (19.86?±?2.73?mg/L). Methanol extract of aerial parts also showed higher activity than α-tocopherol in DPPH (85.56?±?11.51?mg/L) but slightly less (72.90?±?3.66?mg/L) than both the standards in ABTS. Linoleic (aerial 53.9%, corm 43.9%) and palmitic (aerial 22.2%, corm 18%) were found as the major fatty acids.

Discussion and conclusion Some fractions of C. mathewii showed higher antioxidant activities than the standards. There is a need to explore more about this plant.     

Long-term use of gonadotropin-releasing hormone analogues before IVF in women with endometriosis

PURPOSE OF REVIEW: To discuss the relationship between endometriosis and infertility, the impact of endometriosis on assisted reproductive techniques and also the benefits of prolonged use of gonadotropin-releasing hormone analogue before IVF in women with endometriosis. RECENT FINDINGS: The available evidence suggests that endometriosis is strongly associated with infertility. Many studies indicate lower pregnancy and implantation rates even in assisted reproductive cycles in women with endometriosis. It is well known that medical suppression of endometriosis does not appear to be warranted for endometriosis-associated infertility. Prolonged pretreatment with gonadotropin-releasing hormone analogue before IVF has been reported to improve clinical pregnancy rates in infertile women with endometriosis. SUMMARY: Based on the recently published data, infertile women with endometriosis may benefit from long-term pretreatment of gonadotropin-releasing hormone analogue prior to IVF.     

Percutaneous placement of biliary metallic stents in patients with malignant hilar obstruction: unilobar versus bilobar drainage

PURPOSE: To evaluate the necessity of draining more than one hepatic duct in malignant hilar obstructions. MATERIALS AND METHODS: Two hundred seventeen self-expandable uncovered metallic stents (144 biliary Wallstents and 73 Memotherm nitinol stents) were placed percutaneously in 138 patients with unresectable malignant hilar obstructions. The patients included 76 men and 62 women, with a median age of 76 years (range, 43-82 years). Single-duct drainage was achieved in 74 patients (54%) by placing one stent (n = 59) or by placing an additional stent inserted telescopically through the first one (n = 15) to achieve an adequate stent length for long strictures (group 1). In 64 patients (46%), to maintain two-duct drainage, two stents were inserted through dual transhepatic tracts in a "Y" configuration (n = 41; group 2Y) or a single transhepatic tract in a "T" configuration (n = 23; group 2T). RESULTS: The overall technical success rate was 100%, and early clinical response was obtained in 89% of patients. The overall rate of major complications was 5.7% and did not show a statistically significant difference among groups 1, 2Y, and 2T in Bismuth type II, III, and IV obstructions. The patency rate was not statistically significant among groups 1, 2Y, and 2T in Bismuth type II and III obstructions (P >.05). However, in Bismuth type IV obstructions, the patency rate was significantly higher in group 2Y (P =.03; Kruskal-Wallis test). CONCLUSION: There is no need to place more than one stent in Bismuth type I, II, and III hilar obstructions. In Bismuth type IV obstructions, deployment of two parallel stents through dual transhepatic tracts should be performed.     

Thoracic splenosis: Case report of a symptomatic case

Thoracic splenosis is the autotransplantation of splenic tissue in the left thoracic cavity as a result of a splenic injury. This rare pathology is usually asymptomatic and may be discovered on incidental imaging, but the diagnosis often requires invasive procedures such as surgery in order to eliminate a neoplasic origin. We report a rare symptomatic case of a 39-year-old man presenting with chest pain and multiple nodules revealed on a computed tomography scan. The patient underwent a surgical exploration and the pathological studies concluded to a thoracic splenosis. Indeed, the previous medical history of the patient revealed a left thoraco-abdominal traumatism during childhood. The aim of this paper is to emphasize that the diagnosis can now be performed using only imaging techniques such as technetium-99 sulfur colloid or labelled heat-denatured red blood cell scintigraphy to avoid unnecessary invasive procedures including thoracotomy.