Targeted disruption within the CD3 zeta/eta/phi/Oct-1 locus in mouse

To elucidate the role of the CD3 eta subunit of the T cell receptor (TCR) in thymic development, a CD3 eta -/- mouse was generated by gene targeting. Insertion of a neomycin resistance gene into exon 9 of the CD3 zeta/eta/phi locus disrupted expression of CD3 eta and CD3 phi without affecting the expression of CD3 zeta. Little difference was observed between wild type and CD3 eta -/- mice with regard to cellularity or subset composition in thymus and peripheral lymphoid organs. Furthermore, neither alloproliferative responses nor cytotoxic T lymphocyte generation and effector function was affected by the mutation. The effect of the CD3 eta -/- mutation on thymic selection was examined by crossing the CD3 eta knockout animals with anti-HY TCR transgenic animals: the absence of the CD3 eta subunit altered neither positive nor negative selection. Thus, CD3 eta is not required for thymic selection. Of note, the birth rate of the CD3 eta -/- animals was significantly lower than that of wild type or heterozygous animals (P = 0.041-0.002). This unexpected result is probably the consequence of an alteration in mRNA expression of the Oct-1 nuclear transcription factor in CD3 eta -/- animals. The CD3 zeta/eta/phi locus partially overlaps the gene encoding Oct-1 whose transcription is dysregulated by the CD3 eta -/- mutation. Our results clearly underscore the value of characterizing all products of a genetic locus disrupted by gene targeting.

Effectiveness and acceptability of three bowel cleansing regimens

The effectiveness and acceptability of three colon cleansing regimens for colonoscopy were compared in a prospective study in 271 patients stratified as in- and out-patients and randomly assigned to either I) a diet and Senna laxative (X-prep), combined with a saline enema (n = 88); II) 41 of a polyethylene glycol electrolyte lavage solution (Golytely) (n = 90); or III) a combined regimen of Cascara-Salax laxative (PicoSalax) and 1.51 Golytely (n = 93). Patients and colonoscopists indicated independently their overall impression of palatability and convenience and the completeness of the preparation, respectively, on 0- to 10-cm visual analogue scales. No differences were found between the regimens, either for the patients' impression of palatability or for the convenience of the preparation. A significantly cleaner colon was obtained with regimen II in outpatients than with regimen I (p = 0.02), whereas no differences were found either between regimens I and III or between regimens II and III. With regimen I, II, and III, 14%, 8%, and 12% of the patients, respectively, had scores indicating inadequate preparation. Outpatients (n = 175) had significantly cleaner colon than inpatients (n = 96) (p less than 0.001). In conclusion, no clinically important differences were found between the three bowel preparation regimens. An oral irrigation regimen is acceptable to the patients and may be preferable because it provides more flexibility to the endoscopic laboratory.

Involvement of the PPPGHR motif in T cell activation via CD2

Prior studies identified a segment of the CD2 cytoplasmic domain between amino acid (aa) residues 253 and 287 as important in T lymphocyte signal transduction. This region contains two repeats of the sequence motif PPPGHR, thought to form a "cage" structure involved in CD2-mediated signaling. To evaluate this segment, a series of mutant human CD2 molecules were produced by oligonucleotide-directed mutagenesis and inserted into the ovalbumin-specific, I-Ad-restricted murine T-T hybridoma 3DO54.8 using the DOL retroviral system. CD2 M1 (271-272), CD2 M2 (278-279), and CD2 M4 (264-265) mutants replaced the positively charged adjacent aa histidine and arginine (HR) in the wild-type CD2 sequence with aspartic and glutamic acid (DE) at positions 271-272, 278-279, and 264-265, respectively. In addition, a truncation mutant, CD2 M3 (268), containing only 57 of the 117 cytoplasmic aa and terminating before the second PPPGHR sequence, was generated. Stimulation of transfectants CD2 FL, CD2 M1 (271-272), and CD2 M2 (278-279) with anti-T11(2) + anti-T11(3) antibodies resulted in a rise in cytosolic-free calcium [( Ca2+]i) and subsequent interleukin 2 (IL-2) secretion. In contrast, CD2 M4 (264-265) transfectants could not be activated in either assay. Thus, alteration of histidine 264 and/or arginine 265 within the first PPPGHR motif affects the process of signal transduction via CD2, whereas identical mutations in residues at 271-272 or 278-279 were individually without effect. Consistent with these data, CD2 M3 (268) transfectants were able to generate a detectable amount of IL-2 via CD2 triggering. These data support the notion that the PPPGHR motif at aa 260-265 is important for activation of T lymphocytes via the CD2 molecule.

[Endoscopic hemostasis in hemorrhagic peptic ulcer. A review and pilot study of local thrombin injection combined with systemic fibrinolysis inhibition (with tranexamic acid)]

Today, most upper GI-haemorrhages can be handled without surgery. We discuss the available endoscopic haemostatic methods. Injection therapy seems to be as effective as laser-, heater probe- and bipolar electrocoagulation, and is often preferred because the equipment is inexpensive. In a pilot study of 37 patients with haemorrhage from peptic ulcer (13 with active bleeding and 24 with stigmata of recent hemorrhage) we injected thrombin in the ulcer base and treated the patients systemically with an antifibrinolytic drug (tranexamic acid) for five days. Endoscopic follow-up revealed stigmata of recent haemorrhage in 23 patients on day 1 and in eight patients on day 5. "Blood in stomach" was seen in eight patients on day 1 and in two patients on day 5. Four patients had clinical signs of rebleeding, but only one of them needed operation (definite hemostasis 97%). There were no obvious side effects of the treatment. Contrary to other endoscopic methods, local injection of thrombin does not damage the normal mucosa. However, the method has not been sufficiently explored as yet, and cannot be recommended without strict control and follow-up measures. Early control endoscopy seems to be a sensitive way of monitoring haemostasis.

Mercuric chloride activates latent, anion-dependent cation transport systems in the plasma membrane of Ehrlich ascites tumour cells

Electronic cell sizing of Ehrlich ascites tumour cells is presented as a biological test system for assessment of membrane associated effects of toxic compounds. Ehrlich ascites tumour cells readjust their cell volume after osmotic swelling in hypotonic media. This regulatory process (Regulatory Volume Decrease, RVD) involves a net loss of KCl from the cells. Addition of HgCl2 (1 microM) results in a Cl- -dependent acceleration of RVD in hypotonic medium. Cells in isotonic Cl- -containing medium shrink upon addition of HgCl2 due to a Cl- -dependent net loss of K+. In addition, a Cl- -dependent net uptake of Na+ was also seen in the presence of HgCl2. It is concluded that HgCl2 activates a latent K+, Cl- cotransport as well as Na+, Cl- cotransport in Ehrlich cells.

Norwalk virus in Norway: an outbreak of gastroenteritis studied by electron microscopy and radioimmunoassay

An outbreak of acute gastroenteritis affected approximately half of 40 children staying at a holiday centre in Southern Norway. By direct electron microscopy Norwalk-like viruses were demonstrated in 4/8 available stool specimens. No other pathogens were detected. Antibody against these viruses was demonstrated by immune electron microscopy in all of 7 convalescent phase sera but in none of 11 acute phase sera collected. Radioimmunoassay examination showed a rise in titre of Norwalk virus antibody in 6 available paired sera. This outbreak of Norwalk virus gastroenteritis in Norway was thus documented by a combined use of direct and immune electron microscopy and radioimmunoassay.

Evaluation of first 406 patients in urology department based Center for Male Sexual Dysfunction

Four hundred six patients with a complaint of erectile dysfunction were evaluated in a urology department based Male Sexual Dysfunction Center. Results of physical examination, medical and psychosexual history, nocturnal penile tumescence (NPT), penile blood pressure, visual sexual stimulation, hormonal screen, and partner interview were used in establishing the final diagnosis. A summary of the final diagnoses is as follows: organic impotence 117 (28.8%), psychogenic impotence 161 (39.7%), combined factors 102 (25.1%), and dysfunction of unknown origin 26 (6.4%). Data analysis confirms that to establish a diagnosis of organic erectile failure multiple objective measurements in combination with patient and partner history are necessary.