Differential immunofluorescent staining of polymorphonuclear leucocytes for discriminating between surface bound and internalised immunoglobulin

Discrimination between immunoglobulin on the surface of polymorphonuclear leucocytes and immunoglobulin internalised as a result of phagocytosis has been achieved by direct immunofluorescent staining with fluorescein and rhodamine antiglobulin conjugates of identical specificity applied sequentially to live cells in suspension and after fixation on microscope slides. Surface bound antigen is recognised by double staining whereas internalised material is stained only by the conjugate applied to the fixed preparation. This differential staining procedure was evaluated in a model system in which normal PMNs were exposed to small (< 20 s) and large (> 90 s) aggregates of human IgG.     

The role of radiology in extracorporeal shock wave therapy

Extracorporeal shock wave lithotripsy was used for the treatment of 1,252 kidneys and ureters with calculi during a 10-month period at the authors' medical center. Before lithotripsy was performed, excretory urography, radiography, renography, computed tomography, and ultrasound studies were done, when necessary, to locate the calculi. Nine calculi in five kidneys could not be fragmented with lithotripsy. Of 895 patients with calculi less than 2.5 cm in diameter, only 13 (1.5%) required interventional procedures to clear the calculi, whereas of 161 patients with calculi greater than or equal to 2.5 cm, 36 (22.4%) required nephrostomies. A column of calculous debris in the mid and distal portions of the ureter (steinstrasse) was seen in 171 instances (13.6%) after lithotripsy; 62% required interventions. The most common intervention required for successful lithotripsy was retrograde ureteral catheterization. Evaluation and treatment of patients with urolithiasis were largely dependent on radiography and excretory urography.     

Epidemiological features of a new strain of the influenza A virus--influenza A (H1N2) circulating in England and its public health implications

The UK influenza season of 2001/2002 was characterized by widespread geographic circulation of a new subtype of influenza A (H1N2) virus throughout the duration of the season. Younger children were predominantly infected, suggesting primary infection. Despite this, the public health impact of this new virus was minimal. It remains to be seen whether influenza A (H1N2) virus will persist and co-circulate with the previously circulating subtypes of influenza A (H1N1 and H3N2), or whether it was a sporadic recombination event that will disappear. Ultimately, the emergence of a new strain highlights the importance of continual surveillance of circulating viruses.     

The predicted 3D structure of the human D2 dopamine receptor and the binding site and binding affinities for agonists and antagonists

Dopamine neurotransmitter and its receptors play a critical role in the cell signaling process responsible for information transfer in neurons functioning in the nervous system. Development of improved therapeutics for such disorders as Parkinson's disease and schizophrenia would be significantly enhanced with the availability of the 3D structure for the dopamine receptors and of the binding site for dopamine and other agonists and antagonists. We report here the 3D structure of the long isoform of the human D2 dopamine receptor, predicted from primary sequence using first-principles theoretical and computational techniques (i.e., we did not use bioinformatic or experimental 3D structural information in predicting structures). The predicted 3D structure is validated by comparison of the predicted binding site and the relative binding affinities of dopamine, three known dopamine agonists (antiparkinsonian), and seven known antagonists (antipsychotic) in the D2 receptor to experimentally determined values. These structures correctly predict the critical residues for binding dopamine and several antagonists, identified by mutation studies, and give relative binding affinities that correlate well with experiments. The predicted binding site for dopamine and agonists is located between transmembrane (TM) helices 3, 4, 5, and 6, whereas the best antagonists bind to a site involving TM helices 2, 3, 4, 6, and 7 with minimal contacts to TM helix 5. We identify characteristic differences between the binding sites of agonists and antagonists.     

Fire ant venom alkaloid,isosolenopsin A,a potent and selective inhibitor of neuronal nitric oxide synthase

Massive, multiple fire ant, Solenopsis invicta, stings are often treated aggressively, particularly in the elderly, despite limited evidence of systemic toxicity due to the venom. Over 95% of the S. invicta venom is composed of piperidine alkaloid components, whose toxicity, if any, is unknown. To assess a possible pharmacological basis for systemic toxicity, an alkaloid-rich, protein-free methanol extract of the venom from whole ants was assayed for inhibitory activity on the following nitric oxide synthase (NOS) isoforms, rat cerebellar neuronal (nNOS), bovine recombinant endothelial (eNOS), and murine recombinant immunologic (iNOS). Cytosolic NOS activity was determined by measuring the conversion of [(3)H]arginine to [(3)H]citrulline in vitro. Rat nNOS activity was inhibited significantly and in a concentration-dependent manner by the alkaloid-rich venom extract. For nNOS, enzyme activity was inhibited by approximately 50% with 0.33 +/- 0.06 microg of this venom extract, and over 95% inhibition of the three isoforms, nNOS, eNOS, and iNOS, was found with doses of 60 microg in 60 microl reaction mixture. These results indicate that the alkaloid components of S. invicta venom can produce potent inhibition of all three major NOS isoforms. Isosolenopsin A (cis-2-methyl-6-undecylpiperidine), a naturally occurring fire ant piperidine alkaloid, was synthesized and tested for inhibitory activity against the three NOS isoforms. Enzyme activities for nNOS and eNOS were over 95% inhibited with 1000 microM of isosolenopsin A, whereas the activity of iNOS was inhibited by only about 20% at the same concentration. The IC(50) for each of three NOS isoforms was approximately 18 +/- 3.9 microM for nNOS, 156 +/- 10 microM for eNOS, and >1000 microM for iNOS, respectively. Kinetic studies showed isosolenopsin A inhibition to be noncompetitive with L-arginine (K(i) = 19 +/- 2 microM). The potency of isosolenopsin A as an inhibitor of nNOS compares favorably with the inhibitory potency of widely used nNOS inhibitors. Inhibition of NOS isoforms by isosolenopsin A and structurally similar compounds may have toxicological significance with respect to adverse reactions to fire ant stings.     

Bilateral primary renal lymphoma

Background Primary renal lymphoma is rare with no well-defined diagnostic criteria. Aim To describe the first reported case of bilateral and primary renal lymphoma and describe diagnostic criteria. Result and conclusion If a diagnosis of primary renal lymphoma is to be considered, then specific diagnostic criteria (as outlined) must first be satisfied.