Role of a peptidase in phagocyte chemotaxis.

The potencies of N-formylmethionyl (fMet) peptides as chemotactic agents for phagocytes are related to the rates at which they are hydrolyzed. Furthermore, chloromethyl ketones inhibit chemotaxis as do the products of hydrolysis of fMet peptides. The directed migration of cells in response to such peptides is probably brought about by the binding of the peptide to a cell receptor with subsequent cleavage by peptidase specific for aromatic residues, a process that allows the chemical gradient to be detected.     

A role for a ternary complex in nucleating a mineral phase

A mineral phase is precipitated at an accelerated rate from supersaturated solutions of calcium and phosphate in the presence of low concentrations of an heavy metallic cation (Fe²⁺) and a complexing agent (norepinephrine). Data from titration studies and visible absorption spectra of solutions containing the metallic cation, complexing agent and phosphate suggest the formation of a nucleating ternary complex of these components.

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Zusammenfassung Aus an Calcium- und Phosphationen übersättigten Lösungen wird in Gegenwart von geringen Konzentrationen an Fe²⁺-Ionen und komplexbildenden Agentien (Norepinephrin) eine mineralische Phase in beschleunigtem Maße abgeschieden. Im sichtbaren Bereich gemessene Spektren und Titrationen von Lösungen, die metallische Kationen, komplexbildende Agentien und Phosphationen enthalten, legen die Bildung eines keimbildenden Komplexes aus diesen drei Komponenten nahe.

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Résumé Une phase minérale est précipitée a une vitesse accelérée a partir de solutions supersaturées de calcium et de phosphate en présence des basses concentrations d'un cation de métal lourd (Fe²⁺) et d'un agent de liaison (norepinephrine).Les données provenant d'études de titrage et du spectre visible d'absorption des solutions contenant le cation métallique, l'agent de liaison et le phosphate indiquent la formation d'un complexe ternaire initiateur de ces composants.

     

Pathophysiology and assessment of neuropathic pain in Fabry disease

Severe neuropathic pain and hypohidrosis are important symptoms of Fabry disease, particularly in the first three decades of life. The pain is associated with a length-dependent small-fibre neuropathy that also causes a selective deficiency of cold perception. Cold exposure often accentuates the pain and worsens thermal perception. The hypohidrosis leads to poor exercise and heat tolerance. The mechanisms by which alpha-galactosidase A deficiency causes these physiological abnormalities are poorly understood. The stored glycolipid (globotriaosylceramide) may interfere with the function of cellular membrane proteins, such as ion channels, or may lead to cytotoxicity. The characteristic neuropathic pain can be symptomatically treated with various types of anticonvulsant drugs, such as carbamazepine. Improvement in neuropathic pain as a primary outcome measure has been useful in demonstrating that enzyme replacement therapy is effective in improving pain-related quality of life in Fabry disease. CONCLUSIONS: The dysfunction of the peripheral nervous system is easily assessable and more readily reversible with specific therapy than the destructive processes that occur in organs such as the kidney. In future, therefore, it is likely that neuropathic pain, quantitative sensory testing and hypohidrosis will serve as clinical outcome measures for studies of specific and effective therapies for Fabry disease.     

Enzyme replacement therapy in Fabry disease: a randomized controlled trial

CONTEXT: Fabry disease is a metabolic disorder without a specific treatment, caused by a deficiency of the lysosomal enzyme alpha-galactosidase A (alpha-gal A). Most patients experience debilitating neuropathic pain and premature mortality because of renal failure, cardiovascular disease, or cerebrovascular disease. OBJECTIVE: To evaluate the safety and efficacy of intravenous alpha-gal A for Fabry disease. DESIGN AND SETTING: Double-blind placebo-controlled trial conducted from December 1998 to August 1999 at the Clinical Research Center of the National Institutes of Health. PATIENTS: Twenty-six hemizygous male patients, aged 18 years or older, with Fabry disease that was confirmed by alpha-gal A assay. INTERVENTION: A dosage of 0.2 mg/kg of alpha-gal A, administered intravenously every other week (12 doses total). MAIN OUTCOME MEASURE: Effect of therapy on neuropathic pain while without neuropathic pain medications measured by question 3 of the Brief Pain Inventory (BPI). RESULTS: Mean (SE) BPI neuropathic pain severity score declined from 6.2 (0.46) to 4.3 (0.73) in patients treated with alpha-gal A vs no significant change in the placebo group (P =.02). Pain-related quality of life declined from 3.2 (0.55) to 2.1 (0.56) for patients receiving alpha-gal A vs 4.8 (0.59) to 4.2 (0.74) for placebo (P =.05). In the kidney, glomeruli with mesangial widening decreased by a mean of 12.5% for patients receiving alpha-gal vs a 16.5% increase for placebo (P =.01). Mean inulin clearance decreased by 6.2 mL/min for patients receiving alpha-gal A vs 19.5 mL/min for placebo (P =.19). Mean creatinine clearance increased by 2.1 mL/min (0.4 mL/s) for patients receiving alpha-gal A vs a decrease of 16.1 mL/min (0.3 mL/s) for placebo (P =.02). In patients treated with alpha-gal A, there was an approximately 50% reduction in plasma glycosphingolipid levels, a significant improvement in cardiac conduction, and a significant increase in body weight. CONCLUSION: Intravenous infusions of alpha-gal A are safe and have widespread therapeutic efficacy in Fabry disease.     

Evidence for neuroaxonal injury in patients with proteolipid protein gene mutations

The authors used proton MRS to investigate neuropathologic correlates in nine patients with proteolipid protein (PLP) gene mutations who did not show cerebral atrophy on cranial MRI. When compared with 16 age-matched control participants, patients with PLP mutations had significant and widespread decreased brain N-acetyl aspartate, a neuronal marker. The authors conclude that PLP mutations cause neuroaxonal injury, which in turn contributes to the neurologic deficit observed in these patients.     

Inactivation of adenosine A2A receptor impairs long term potentiation in the accumbens nucleus without altering basal synaptic transmission.

The nucleus accumbens is considered to be critically involved in the control of complex motivated behaviors. By modulating its glutamatergic excitatory input, mesolimbic dopaminergic afferents have been implicated in the reinforcing properties of drugs of abuse. However, they might not represent the only path for influencing the accumbens output. The aim of this study was to investigate possible modulation of synaptic transmission at this glutamatergic synapse by adenosine receptors. The standard field potential recording technique was used on brain slices from wild-type and A2A receptor-deficient mice. Neither the stimulus-response relationship nor paired-pulse facilitation was altered in the mutant mice. In both genotypes, the activation of A1 receptors by 2-chloro-N6-cyclopentyladenosine reduced the field excitatory postsynaptic potential (fEPSP) slope to a similar extent. In wild-type slices, activation or blockade of A2A receptors by 2-[4-(carboxyethyl)phenylethylamino]-5'-N-ethylcarboxamidoadenosine and 4-(2-[7-amino-2-(2-furyl)[1,2,4]-triazolo-[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol, respectively, did not modify the synaptic transmission. Moreover, a long lasting pre-activation of these A2A receptors did not influence the A1 receptor-mediated reduction in fEPSP slope. Long term potentiation (LTP) of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionate (AMPA) receptor-mediated synaptic transmission could be elicited in both wild-type and A2A receptor-deficient mice. However, LTP appeared to be quantitatively modulated by the A2A receptor pathway since the level of potentiation was reduced in A2A receptor-deficient mice as well as in slices of wild-type mice in which the A2A receptor pathway was blocked. The involvement of the cAMP-dependent protein kinase was supported by the reduction in potentiation level in slices of wild-type mice treated with adenosine 3',5'-cyclic monophosphorothiotate, 8-(4-chlorophenylthio)-Rp isomer, an inhibitor of this enzyme.These data provide evidence that the adenosine acting at the A2A receptor is implicated in events directly or indirectly related to LTP induction in the accumbens whereas it is not involved in the regulation of the basal AMPA receptor-mediated excitatory synaptic transmission.     

The Effect of Neoadjuvant Chemotherapy on Perioperative Outcomes in Patients Who Have Bladder Cancer Treated with Radical Cystectomy: A Population-based Study

Background

Although therapeutic guidelines recommend the use of neoadjuvant chemotherapy before radical cystectomy (RC) in patients who have muscle-invasive bladder cancer (MIBC), this approach remains largely underused. One of the main reasons for this phenomenon might reside in concerns regarding the risk of morbidity and mortality associated with neoadjuvant chemotherapy.

Objective

To compare perioperative outcomes between patients receiving neoadjuvant chemotherapy and those treated with RC alone.

Design, setting, and participants

Relying on the Surveillance Epidemiology and End Results–Medicare-linked database, 3760 patients diagnosed with MIBC between 2000 and 2009 were evaluated.

Intervention

RC alone or RC plus neoadjuvant chemotherapy.

Outcome measurements and statistical analysis

Complications occurred within 30 and 90 d after surgery. Heterologous blood transfusions (HBTs), length of stay (LoS), readmission, and perioperative mortality were compared. To decrease the effect of unmeasured confounders associated with treatment selection, propensity score–matched analyses were performed.

Results and limitations

Overall, 416 (11.1%) of patients received neoadjuvant chemotherapy. Following propensity score matching, 416 (20%) and 1664 (80%) patients treated with RC plus neoadjuvant chemotherapy and RC alone remained, respectively. The 30-d complication, readmission, and mortality rates were 66.0%, 32.2%, and 5.3%, respectively. The 90-d complication, readmission, and mortality rates were 72.5%, 46.6%, and 8.2%, respectively. When patients were stratified according to neoadjuvant chemotherapy status, no significant differences were observed in the rates of complications, HBT, prolonged LoS, readmission, and mortality between the two groups (all p ≥ 0.1). These results were confirmed in multivariate analyses, where the use of neoadjuvant chemotherapy was not associated with higher risk of 30- and 90-d complications, HBT, prolonged LoS, readmission, and mortality (all p ≥ 0.1). Our study is limited by its retrospective nature.

Conclusions

The use of neoadjuvant chemotherapy is not associated with higher perioperative morbidity or mortality. These results should encourage wider use of neoadjuvant chemotherapy when clinically indicated.

Patient summary

Chemotherapy before radical cystectomy in patients with muscle-invasive bladder cancer does not increase the risk of complications or death. The use of chemotherapy should be strongly encouraged, as recommended by clinical guidelines, given its benefits.     

Tumor cell motility

Tumor cell motility is required for invasion and metastasis. The locomotory machinery of the cell includes cell projections called pseudopodia which are regulated by a complicated linkage between cell surface receptors or sensors and the internal cytoskeleton. Recently a new class of motility stimulating cytokines have been identified. These cytokines can function as autocrine motility factors and require a pertussis toxin sensitive G protein pathway to transduce a random motile response.