Histamine H1-receptors mediate phosphoinositide hydrolysis in astrocyte-enriched primary cultures

Astrocyte-enriched primary cultures of newborn rat brain hemispheres, prelabeled with [³H]inositol, accumulated [³H]inositol phosphate but not [³H]inositol bis-and tris-phosphate, after exposure to histamine for 60 min in the presence of 10 mM LiCl. The response to histamine was not a function of contaminating meningeal fibroblasts since no accumulation of [³H]inositol phosphate was elicited by histamine in meningeal cultures. The stimulation of phosphoinositide hydrolysis by histamine in astrocytes was dose-dependent (EC₅₀ = 1.7 μM, maximal effect = 345% over basal levels) and was mimicked by several H₁-receptor agonists. The use of selectiver receptor antagonists confirmed that the histamine response was the result of activation of H₁-receptors. The histamine-induced [³H]inositol phosphate accumulation was completely abolished by omission of Ca²⁺ from the incubation medium. Astrocyte membranes specifically bound the radiolabeled H₁-antagonist, [³H]mepyramine with an affinity (K_d = 5.9 nM) and a density of binding sites (B_max = 113 fmol/mg protein) similar to rat brain. These results demonstrate the presence of functional histamine H₁-receptors in rat brain astrocytes and suggest a role for histamine as a neuromodulator of astrocyte function.     

Retrograde atrial kick in acute aortic regurgitation. study of mitral and pulmonary venous flow velocities by transthoracic and transesophageal echocardiography

Background and hypothesis: The purpose of this study was the comprehensive evaluation of the changes in pulmonary venous and mitral flow velocities of patients with acute and chronic severe aortic regurgitation. Transmitral flow velocities obtained with pulsed-wave Doppler echocardiography have been used to provide information on left ventricular (LV) filling and diastolic function. Pulmonary venous flow tracings are an important adjunct to LV inflow pattern in assessing LV diastolic function. Methods: Fourteen patients with severe aortic regurgitation (8 chronic and 6 acute) and in sinus rhythm were examined by transthoracic and transesophageal pulsed Doppler echocardiography. Mitral and pulmonary flow velocities were recorded and compared. All patients had ejection fractions > 40%. Results: Early mitral flow peak velocity was higher in patients with acute regurgitation (p<0.001). The mitral A wave was absent in five patients with acute regurgitation. In contrast, a prominent reverse atrial pulmonary systolic wave AR was demonstrated in these patients. Peak diastolic velocity of the pulmonary venous flow was greater in patients with acute aortic regurgitation (0.76 ± 0.13) than in patients with chronic aortic regurgitation (0.40 ± 0.09) (p<0.001). Peak systolic velocity did not differ significantly between the two groups. The systolic fraction of pulmonary venous flow in patients with acute aortic regurgitation was lower (0.43 ± 0.05) than that of patients with chronic regurgitation (0.63 ± 0.1) (p<0.01). All patients with acute aortic regurgitation had an S/D ratio < 1, while those with chronic regurgitation had an S/D >1 (p< 0.001) and an E/A<1. Conclusion: Patients with severe acute aortic regurgitation showed a retrograde atrial kick (absence of transmitral A wave with prominent pulmonary AR wave). These patients had an S/D ratio < 1 (restrictive Doppler pattern). Patients with chronic aortic regurgitation exhibited a Doppler pattern of abnormal LV relaxation (E/A <1, S/D > 1).     

Pentasomy 21 with two isochromosomes 21 in a case of acute myeloid leukemia without maturation.

Here, we report a 72-year-old male patient with acute myeloid leukemia (AML) without maturation. Cytogenetic study of a bone marrow culture revealed the following karyotype: 47,XX,+21,+i(21)(q10)x2. Fluorescence in situ hybridization study with a locus specific probe for 21q22 verified a pentasomy of 21q as a sole clonal cytogenetic abnormality. To our knowledge, this is the first report of pentasomy 21q in AML without Down syndrome.     

Evaluation of cutting patterns produced in primary teeth by an air-abrasion system.

OBJECTIVE: The aim of this in vitro study was to assess the effect of tip diameter, nozzle distance, and application time of an air-abrasion system for cavity preparation on the enamel of primary teeth. METHOD AND MATERIALS: Forty exfoliated primary teeth were air abraded with a microabrasion machine used with a handpiece with an 80-degree-angle nozzle, 50-micron abrasive particle size, and 80-psi air pressure. The effects of 0.38- or 0.48-mm inner tip diameter, 2- or 5-mm distance from tip to tooth surface, and 15 or 30 seconds of application time on cutting efficiency were evaluated. Cutting width and depth were analyzed and measured from scanning electron micrographs. RESULTS: Statistical analysis revealed that the width of the cuts was significantly greater when the tip distance was increased. Significantly deeper cavities were produced by a tip with a 0.48-mm inner diameter. The application time did not influence the cuts. CONCLUSION: The cutting patterns found in this study suggest that precise removal of enamel in primary teeth is best accomplished when a tip with a 0.38-mm inner diameter is used at a 2-mm distance.     

Congenital and acquired anomalies of the portal venous system.

Knowledge of the normal anatomy, most frequent variants, and congenital and acquired anomalies of the portal venous system is of great importance for liver surgery and interventional procedures such as creation of transjugular intrahepatic portosystemic shunts. Radiologic studies of the portal venous system include color Doppler ultrasonography (US), computed tomography (CT), magnetic resonance imaging, and arterial or direct portography. Among the most common branching variants of the portal vein are trifurcation, right anterior portal branch arising from the left portal vein, and right posterior portal branch arising from the main portal vein. Agenesis of the right or left portal vein is the most frequently reported congenital anomaly. Venous collateral vessels due to portal hypertension and cavernous transformation of the portal vein are best evaluated with cross-sectional imaging. Intrahepatic portosystemic, arterioportal, and arteriosystemic fistulas and associated perfusion anomalies have characteristic features at dual-phase helical CT. Color Doppler US is the single most useful tool for demonstration of aneurysms of the portal venous system and bland or neoplastic portal vein thrombosis. CT is also the best means of evaluating gas in the portal venous system, which is no longer an ominous sign and must be differentiated from aerobilia.     

Phacomatosis Pigmentovascularis: A New Syndrome? Report of Four Cases

We examined four patients who had a combination of extensive nevus flammeus, significant oculocutaneous pigmentation, and severe neurologic alterations. All cases were sporadic. The vascular and neurologic alterations were clinically similar to those observed in the Sturge-Weber syndrome. The capillary vessels are ultrastructurally different in phacomatosis pigmentovascularis from those of a nevus flammeus in the Sturge-Weber syndrome; however, melanocytes of normal aspect were present in the middle and deep dermis. The characteristic oculocutaneous pigmentation probably represented a noncoincidental association. The term phacomatosis pigmentovascularis seems appropriate for this apparently new neurocutaneous syndrome.     

A Cost-Effectiveness Analysis of a Peak Flow-Based Asthma Education and Self-Management Plan in a High-Cost Population

Background. Asthma education and action plans (AP) have been recognized as important components in the optimal management of asthma. Studies have differed on the importance of a peak flow-based self-management plans in reducing health care costs and use due to asthma exacerbation. Objective. To analyze the cost-effectiveness of peak flow-based action plans in reducing costs associated with ER visits and hospitalizations due to acute asthma exacerbation in a population of high-risk and high-cost patients, defined as patients with moderate to severe asthma with a history of recent urgent treatment in the ER or hospitalization due to asthma. Methods. A literature review of randomized clinical trials comparing peak flow-based (PFB) action plans, symptom-based (SB) action plans, and usual care/no action plan (NAP) was performed. Probability values regarding the effectiveness of each alternative (as measured by increase/decrease in ER visits and hospitalizations over a 6-month period) were derived. Incremental cost-effectiveness and cost-benefit ratios were calculated for each alternative. Sensitivity analyses were performed. Results. For high-risk and high-cost asthma patients, our analysis revealed that the most cost-effective alternative for reducing ER visits was a peak flow-based self-management plan. The peak flow-based self-management program had an incremental cost-effectiveness (C/E) ratio of $ 60.57 per ER visit averted compared to usual care/NAP and a C/E ratio of $31.46 compared to the SB-AP. The PFB-AP was also the most cost-effective in reducing asthma hospitalization costs with an incremental C/E ratio of $300 per hospitalization prevented, compared with usual care and a C/E ratio of $311, compared to a SB-AP. Analysis yielded a cost-benefit ratio of 13.79 for the PFB-AP compared to NAP; the SB-AP had a cost-benefit ratio of 11.53 compared to NAP. Conclusion. Cost-effectiveness and cost-benefit analyses reveal that for high-cost patients, a peak flow-based asthma education and self-management plan program is the most cost-effective alternative in reducing costs associated with ER visits and hospitalizations due to asthma exacerbation. Further refinements to this cost-effectiveness analysis including measuring changes in drug use and costs and patients' productivity losses need to be pursued and may demonstrate additional cost-savings due to peak flow-based asthma education plans.     

Hepatoprotective Activity of Xanthones and Xanthonolignoids Against tert-Butylhydroperoxide-Induced Toxicity in Isolated Rat Hepatocytes—Comparison with Silybin

Purpose. Synthesize and evaluate the protective activity against tert-butylhydroperoxide-induced toxicity in freshly isolated rat hepatocytes of trans-kielcorin, trans-isokielcorin B, as well as their respective building blocks 3,4-dihydroxy-2-methoxyxanthone and 2,3-dihydroxy-4-methoxyxanthone. Methods. Wistar rats, weighing 200-250g were used. Hepatocyte isolation was performed by collagenase perfusion. Incubations were performed at 37°C, using 1 million cells per milliliter in modified Krebs—Henseleit buffer. The protective activity was evaluated by measuring reduced and oxidized glutathione, lipid peroxidation and cell viability after inducing toxicity with tert-butylhydroperoxide (1.0 mM, 30 min), with or without the studied compounds in the concentrations of 0.025, 0.050, 0.100 and 0.200 mM. Silybin was tested in the same experimental conditions to serve as a positive control. Results. Using these concentrations, the tested compounds prevented tert-butylhydroperoxide-induced lipid peroxidation and cell death in freshly isolated rat hepatocytes. All compounds were also effective in preventing perturbation of cell glutathione homeostasis in some extent. 3,4-Dihydroxy-2-methoxyxanthone and 2,3-dihydroxy-4-methoxyxanthone were more effective than trans-kielcorin and trans-isokielcorin B respectively. Silybin was less effective in protecting cells against lipid peroxidation and loss of cell viability than the four xanthonic derivatives. Conclusions. The tested compounds protected the freshly isolated rat hepatocytes against tert-butylhydroperoxide-induced toxicity.     

Pediatric elbow fractures: MRI evaluation

Magnetic resonance imaging (MRI) was performed in eight patients under the age of 8 years who suffered elbow fractures, to assess possible fracture extension into the distal nonossified epiphysis of the humerus in seven cases and to determine the displacement and location of the radial head in one case. MRI allowed accurate depiction of the fracture line when it extended into the cartilaginous epiphysis. In four cases, MRI findings were confirmed at surgery. In five cases, surgery was obviated because no articular extension of the fracture was seen on MRI (4 cases) or because no displacement was noted (1 case). In one patient, the plain film diagnosis of a Salter type II fracture was changed to Salter type IV on the basis of the MRI findings. It is concluded that MRI might play a role in the preoperative evaluation of pediatric patients presenting with elbow trauma when extension of the fracture cannot be determined with routine radiographic studies. Elbow injuries in children may be difficult to diagnose by routine clinical and radiographic techniques [1, 4, 12, 14]. Diagnostic difficulty is due to the presence of multiple ossification centers of the distal humeral epiphysis and proximal radius and ulna; these are mostly cartilaginous until the age of 11–12 years and therefore invisible on radiographs. Following distal radial and distal tibial physeal fractures, epiphyseal elbow injuries are the most frequent epiphyseal injuries [8, 16]. These fractures tend to be unstable and often require surgical intervention. In addition, lasting sequelae such as cubitus valgus and delayed ulnar nerve palsy can occur if these fractures are not treated properly [8]. Most elbow fractures suspected to be unstable by clinical and radiographic evaluation are operated upon without additional imaging. Occasionally, arthrography or computed arthrography are used to assess epiphyseal extension and cartilaginous malignment [1, 3, 4]. Because of its ability to depict cartilage, MRI provides a noninvasive means of gaining information regarding the nonossified epiphysis. The purpose of this article is to present our preliminary experience using magnetic resonance imaging (MRI) for the detection of articular extension of elbow fractures and determination of displacement of fragments.