The N-DSK gamma-chain binds to immunoprecipitated GP IIb-IIIa

The CNBr-split N-terminal disulphide knot of the fibrinogen molecule (N-DSK) binds to ADP-stimulated gel-filtered platelets and immunoprecipitated fibrinogen receptor. To investigate which part of the N-DSK molecule that is involved in this binding, the glycoprotein IIb-IIIa complex (the fibrinogen receptor) was immunoprecipitated in crossed immunoelectrophoresis of Triton X-100 extracts of platelets against rabbit antibodies to whole platelet proteins. The immunoelectrophoresis plates were incubated with solubilized, carboxymethylated 125I-labelled A alpha -, B beta - or gamma-chains of N-DSK, and investigated for binding by autoradiography. The N-DSK gamma-chain, but not the A alpha - or B beta -chains demonstrated binding to the GP IIb-IIIa complex. These results show that the fibrinogen molecule contains a third sequence of amino acids, in addition to the two previously reported ones that can be involved in binding of fibrinogen to the fibrinogen receptor on the platelets.     

Puncture technique and postural postdural puncture headache. A randomised, double-blind study comparing transverse and parallel puncture

Background: This clinical study was conducted in order to investigate the effect of two different orientations of the bevel during dural puncture on development of postural postdural puncture headache (PPDPH).
Methods: Two hundred and eighteen patients aged 18 to 50 years scheduled lor minor non-obstetric surgery using spinal anaesthesia (SA) were included in this randomised, double-blind study. Dural puncture was performed using a 0.42 mm O.D. (27-g) Quincke spinal needle with the orientation of the bevel parallel or transverse relative to the longitudinal axis of the dural cylinder. All patients were blinded with regard to the puncture technique, and so was the anaesthesiologist performing a telephone interview 5 to 7 days postoperatively. The occurrence and duration of headache, backache and other complaints were recorded. Headache was classified as PPDPH or non-PPDPH, and intensity of the headache was registered using a numerical rating scale (NRS) from 0 to 10.
Results: Two hundred and twelve patients with a mean age of 35.3 years completed the study, 106 in each group. The two groups were comparable with regard to mean age, sex, local anaesthetics used and surgical procedure performed. Headache occurred in 44 patients postoperatively. PPDPH was diagnosed in 4/106 patients (3.8%) in the parallel group and 24/106 (22.6%) in the transverse group ( P <0.0002). Postoperative backache occurred in 31 and 20 patients (parallel compared to transverse) (NS).
Conclusions: Dural puncture with the bevel of the needle transverse to the longitudinal axis of the dural cylinder gave significantly more cases of PPDPH than puncture with the bevel parallel to this axis even when using a 27-g Quincke needle. When using Quincke bevelled needles care must be taken to assure that the orientation of the bevel is parallel to the longitudinal axis of the dural sac.     

Identification of platelet antigens by monoclonal antibodies using crossed immunoelectrophoresis with immunoblotting of the monoclonal antibody

A method is described for the identification of antigens by monoclonal antibodies. This is applicable whenever precipitating antibodies to the same antigens from a different species are available. The method is based upon: Separation and immunoprecipitation of cellular proteins with a polyspecific antiserum in crossed immunoelectrophoresis in the presence of the non-denaturing detergent Triton X-100 and the monoclonal antibody. Coprecipitation of the monoclonal antibody with its antigen. Subsequent passive transfer of the monoclonal antibody in the antibody-antigen complex onto a nitrocellulose membrane. Visualization of the blotted antibody using an enzyme-linked secondary antibody and a chromogenic substrate. Identification of the corresponding antigen by comparisons to the immunoprecipitate pattern of the original immunoplate. To test this method we have analyzed the detection of the antigens recognized by six previously described monoclonal antibodies against platelet membrane proteins and von Willebrand factor. Specific immunoblots were obtained in each case using small amounts of monoclonal antibodies. Thus, the technique provides an alternative when epitopes are denatured by SDS, and avoids the use of radioactively labelled monoclonal antibodies.     

The comparison of 2-18F-2-deoxyglucose and 15-(ortho-123I-phenyl)-pentadecanoic acid uptake in persisting defects on thallium-201 tomography in myocardial infarction

The myocardial uptake of glucose and fatty acids into 201Tl redistribution defects were studied in 32 patients with myocardial infarction by tomography using 2-18F-2-deoxyglucose (FDG) and 15-(ortho-123I-phenyl)-pentadecanoic acid (oPPA). A total of 1153 segments were analyzed, 408 (35%) of which showed a persistent thallium-defect in stress-redistribution images. Of the segments with a decreased 201Tl uptake in these redistribution tomograms, 50.5% had a decreased uptake of both FDG and oPPA; in 21.8% FDG as well as oPPA uptake was within normal range. Normal FDG uptake but decreased oPPA uptake was detected in 17.4%, whereas 10.3% of the segments had normal oPPA uptake but decreased FDG uptake (chi-square test, p less than 0.001). A significant correlation of FDG and oPPA uptake (r = 0.51) was found in the segments with persistent 201Tl defect. Thus, a substantial fraction of persistent thallium-defects after healed myocardial infarction exhibit FDG as well as oPPA uptake, probably due to residual fatty acid metabolism in partially ischemic regions.     

Phosphorylation of the estradiol receptor in MCF-7 human breast cancer cells in culture

Double labelling and Western blot techniques were used to demonstrate phosphorylation of estradiol receptor. Cells in monolayer culture were incubated with [32P]orthophosphate for 18 h followed by covalent whole cell labelling of the estradiol receptor with tritiated tamoxifen aziridine [( 3H]TA). Labelled receptor was precipitated with the monoclonal antibodies H222 or JS 34/32, coupled to protein A-Sepharose, and purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), or transferred to nitrocellulose paper. Receptor protein was detected on the Western blot with the monoclonal antibody H222 and rabbit anti-rat peroxidase conjugate. Phosphorylated receptor was visualized by autoradiography. Tritium and 32P activities were monitored in the gels. Two phosphorylated forms of the receptor (molecular weights 67 and 50 kDa) have been detected in MCF-7 cells. Estradiol treatment of the cells was found to increase phosphorylation of the receptor. In estradiol-treated cells both phosphorylated receptor forms were present mainly in the nuclear extract. Both forms bound [3H]TA as evidence by SDS-PAGE. [3H]TA binding was abolished by excess non-radioactive estradiol. In addition two phosphorylated proteins of approximately 120 and 90 kDa were regularly coprecipitated with receptor in cytosol. These proteins did not bind [3H]TA. The 90 kDa phosphorylated protein was identified as a heat shock protein (hsp-90).     

Can the F‐Response be Volitionally Repressed during Functional Electrical Stimulation?

Objective The purpose of this study was to test if the F‐response can be repressed volitionally. Normally, the F‐response is used for clinical diagnostics but it also has an important influence on the design of a neural prosthesis involving functional electrical stimulation (FES) and the use of volitional myoelectric signal (MES) for control. Methods Ten neurologically normal subjects were trained to reduce the level of the F‐response from the anterior tibial muscle. The nerve to the anterior tibial (TA) muscle was stimulated with constant intensity and frequency (16.6 pulses per second) and the surface myoelectric signal (MES) from the muscle was digitally processed to estimate the F‐level. Training was carried out by giving the subject visual feedback on a computer screen of the F‐level during the stimulation with the task of keeping the level as low as possible. Each subject had five sessions consisting of 20 stimulation tests, lasting 30 sec each. The subjects acted as their own control and changes in the F‐level during the stimulation tests, sessions, and trials, were analyzed. Results There was a significant (p < 0.001) increase in the F‐response level within the test period of constant stimulation, but a significant (p < 0.001) decrease from the first to the last test in the session was found. From the first to the last session of a trial, the change was found not significant. Conclusion The level of the F‐response may change locally, but there is no indication that a subject can volitionally learn to repress the response, even when given feedback information about the actual level. Therefore the F‐waves in the myoelectric signal from a stimulated muscle has to be accounted for when designing devices using a stimulated muscle response for myoelectric control such as eliminating the F‐interval from the recorded signal.     

Proteinuria, hematuria, and leukocyturia in children with mixed urinary and intestinal schistosomiasis

Quantitative parasitological assessment and quantitative analysis of proteinuria, hematuria, and leukocyturia were carried out in 182 Sudanese schoolboys with mixed urinary and intestinal schistosomiasis. Pathological proteinuria was found in 73% of patients (median = 380, 95% confidence limits = 200 to 500 mg/liter). The median protein/creatinine ratio was 0.54. SDS polyacrylamide gel electrophoresis showed an excretion of albumin, transferrin, and IgG consistent with a postrenal pattern of proteinuria. Pathological erythrocyturia occurred in 84% of patients (median = 255, 95% CL = 95 to 629 cells/microliter) and leukocyturia in 77% of patients (median = 148, 95% CL = 93 to 246 cells/microliter). Phase contrast microscopy revealed intact erythrocytes, suggestive of postrenal hemorrhage. Proteinuria, erythrocyturia, and leukocyturia correlated significantly with the ova excretion in the urine, but not with egg excretion in the stool. Oxamniquine reduced ova excretion in the stool but did not influence pathological urine findings. In patients treated effectively with Praziquantel or Metrifonate, pathological PU, EU, and LU decreased markedly 1 month post treatment. PU in severely proteinuric patients reached physiological values 5 months post therapy. We suggest that the proteinuria, erythrocyturia, and leukocyturia in mixed schistosomiasis were of postrenal origin.