An αIIb ß3 antagonist prevents thrombosis without causing Fc receptor γ-chain IIa-mediated thrombocytopenia.

Essentials FcγRIIa-mediated thrombocytopenia is associated with drug-dependent antibodies (DDAbs). We investigated the correlation between αIIb ß3 binding epitopes and induction of DDAbs. An FcγRIIa-transgenic mouse model was used to evaluate thrombocytopenia among anti-thrombotics. An antithrombotic with binding motif toward αIIb ß-propeller domain has less bleeding tendency. SUMMARY: Background Thrombocytopenia, a common side effect of Arg-Gly-Asp-mimetic antiplatelet drugs, is associated with drug-dependent antibodies (DDAbs) that recognize conformation-altered integrin αIIb ß3 . Objective To explore the correlation between αIIb ß3 binding epitopes and induction of DDAb binding to conformation-altered αIIb ß3 , we examined whether two purified disintegrins, TMV-2 and TMV-7, with distinct binding motifs have different effects on induction of αIIb ß3 conformational change and platelet aggregation in the presence of AP2, an IgG1 inhibitory mAb raised against αIIb ß3 . Methods We investigated the possible mechanisms of intrinsic platelet activation of TMV-2 and TMV-7 in the presence of AP2 by examining the signal cascade, tail bleeding time and immune thrombocytopenia in Fc receptor γ-chain IIa (FcγRIIa) transgenic mice. Results TMV-7 has a binding motif that recognizes the αIIb ß-propeller domain of αIIb ß3 , unlike that of TMV-2. TMV-7 neither primed the platelets to bind ligand, nor caused a conformational change of αIIb ß3 as identified with the ligand-induced binding site mAb AP5. In contrast to eptifibatide and TMV-2, cotreatment of TMV-7 with AP2 did not induce FcγRIIa-mediated platelet aggregation and the downstream activation cascade. Both TMV-2 and TMV-7 efficaciously prevented occlusive thrombosis in vivo. Notably, both eptifibatide and TMV-2 caused severe thrombocytopenia mediated by FcγRIIa, prolonged tail bleeding time in vivo, and repressed human whole blood coagulation indexes, whereas TMV-7 did not impair hemostatic capacity. Conclusions TMV-7 shows antiplatelet and antithrombotic activities resulting from a mechanism different from that of all other tested αIIb ß3 antagonists, and may offer advantages as a therapeutic agent with a better safety profile.

Immunostaining of glutamine synthetase is a sensitive and specific marker for diagnosing focal nodular hyperplasia in needle biopsy.

AIMS: Focal nodular hyperplasia (FNH) has characteristic histological features which may not be seen in needle biopsy specimens. We investigate the diagnostic role of glutamine synthetase (GS) in needle biopsy specimens. METHODS: Sixty-one hepatic tumours were categorised into 20 'definite' FNHs, 13 'probable' FNHs, and 28 cases without specific diagnosis. Needle biopsy specimens of 92 non-tumourous lesions, 25 well-differentiated hepatocellular carcinomas (WDHCCs), and 4 high-grade dysplastic nodules (HGDNs) and resection specimens of 10 macroregenerative nodules were also selected for immunohistochemical stain of GS for comparison. RESULTS: All 20 'definite' FNHs, nine 'probable' FNHs, and five cases without specific diagnosis expressed typical map-like staining pattern of GS. The demographic data of these five cases were similar to those of FNH. All cases of chronic hepatitis B and C, cirrhosis, macroregenerative nodule and peritumourous liver tissue showed normal pericentral/periseptal pattern. Fifteen of 25 WDHCCs and one HGDN showed diffuse pattern. Ten WDHCCs and two HGDNs showed negative staining. One HGDN showed mosaic pattern. CONCLUSIONS: Immunohistochemical staining of GS increases the diagnostic sensitivity of FNH in needle biopsy, especially in those without typical morphology. It also helps in differentiating FNH from other tumourous and non-tumourous lesions.

[Clinical experience of nerve-sparing radical prostatectomy].

A total of 18 patients underwent nerve-sparing radical prostatectomy for clinical stage B1 or B2 prostatic cancer. An operation was performed according to the modified technique originally described by Walsh and associates. The operative technique involved three steps: 1) accurate ligation of dorsal vein complex, which makes a relatively bloodless field and makes it possible to dissect the lateral pelvic fascia from the prostate; 2) the incision in the lateral pelvic fascia is made anterior to the neurovascular bundle; 3) the lateral pedicle is divided close to the prostate. There were no major intraoperative complications such as rectal perforation or ureteral injury. The mean blood loss was 802 g (340-1600 g) and the average duration of surgery was 173 minutes. Eleven patients had no blood transfusions. Postoperatively, there was a wound infection in one case. Mild bladder neck contracture in one case responded to single dilatation. Sexual function was evaluated in 16 of the patients who have been followed for more than three months and who had not received hormone therapy postoperatively. Of 16 patients 6 (37%) had return of erectile function. Return of erections required 3-15 months (average 9 months). Patients under 70 years old had a higher incidence (80%) of return of erections than those over 70 years old. Four of the 6 patients had tumor involvement confined to the prostate. Initially most patients had significant amounts of stress incontinence. This resolved within the first or second postoperative month. Finally 4 had slight stress urinary incontinence but no patients had total incontinence. The results suggest that nerve-sparing radical prostatectomy is an anatomically safe approach. It can contribute to the quality of life in men at a stage when it is still curable.

[Clinical experience with the Kock continent ileal urinary reservoir].

From May 1985 through July 1987, 22 patients underwent Kock continent ileal reservoir for urinary diversion. There were 19 males and 3 females, between 38 and 82 years old (mean age 63.1 years). A one-stage radical cystectomy and Kock pouch construction were performed in 21 patients. One patients was converted from standard ileal conduit to this new reservoir. The keys to success of the Kock pouch are creation and maintenance of the nipple valve to prevent reflux and to ensure continence. Mesenteric fat is removed with CUSA for 8 cm along the afferent-efferent limbs of the pouch and exclusion of mesentery is limited for only 3-4 cm. This important modification will ensure adequate ileal intussusception and vascular supply to the valves. To prevent eversion and prolapse, the nipple valve is anchored to the wall of reservoir. A strip of sauvage filamentous Dacron serves as a collar to fix the afferent-efferent limbs to the pouch. There were 2 postoperative deaths and two major early complication: 1 acute renal failure and 1 intestinal fistula, both of which were treated conservatively. Late complications occurred in 6 patients. Of these 6 patients, 1 required reoperation and revision of the continence valve mechanism and 1 required hospitalization for entero-pouch fistula. Serum electrolytes and vitamin B12 remained normal in all patients. Patients perform self-catheterization every 4-6 hours during the day and once at night for volumes ranging up to 1,000 ml. The end result in 19 of 20 patients was excellent.(ABSTRACT TRUNCATED AT 250 WORDS)

[Penile implantation surgery for organic impotence due to radical cystectomy or prostatectomy].

Implantation surgery was performed twelve times in eleven patients with organic impotence, mainly due to radical cystectomy and prostatectomy against malignancy, between March, 1982 and April, 1987. A self-contained type prosthesis (AMS Hydroflex(TM] was used in 7 cases, reservoir type inflatable prosthesis (AMS 700TM) in 2, malleable semirigid type (ESKA-Jonas Silicon Silver(TM) Trimming Tip Version) in 2, and nonmalleable semirigid type (Fuji system Finney type) in 1 case. In the last case, the prosthesis was replaced by AMS Hydroflex 4.5 years later at patient's wish. Excellent results and good patients' acceptance were gained with inflatable-type prosthesis (AMS 700 and Hydroflex) in 7 out of 8 cases (88%), whereas concealment problems were produced by semirigid type prosthesis (Finney and Jonas). Experience with AMS Hydroflex penile implantation is reported for the first time in the Japanese literature. Intraoperatively, it was sometimes difficult to implant a pair of Hydroflex rods into both of the corpus cavernosum. Postoperative perineal pain was almost constantly seen and in one patient, penile edema continued for three weeks and subsided spontaneously in two months. In another patient, the length of the prosthesis (15 cm) was short, and exchange to the longer one (17 cm) was necessary. In this patient, the longer Hydroflex caused erosion of the glans to necessitate its removal on one side. From our experience, the diameter (11 mm) of the Hydroflex seems to be too big for the average Japanese patient. The operative procedures and results of each kind of the prostheses are briefly discussed.

[Experimental and clinical studies on calcium urolithiasis: (I) Animal model for calcium oxalate urolithiasis using ethylene glycol and 1-alpha (OH) D3].

As calcium oxalate stones are the most important component in urolithiasis, an experimental model has to be designed to clarify the pathogenesis and aid in their prevention. Hyperoxaluria as well as hypercalciuria were produced in rats by administering ethylene glycol (0.5%, in drinking water administered ad libitum) and 1-alpha (OH) D3 (0.5 micrograms/rat given every other day), respectively, for three to four weeks. Neither drug alone produced stones efficiently as did the combination regimen of these two compounds. The occurrence of stones was 77.3%, and with only a moderate degree of renal functional impairment. Biochemical and histological data were obtained using this model.

[Ultrasound-guided renal cyst puncture and 95% ethanol instillation. Part 2: Morphological and functional alterations].

Ultrasound-guided renal cyst puncture was performed on 22 cysts which were then 95% ethanol instilled to prevent recurrence of cystic fluid. Cystic lesions disappeared on the ultrasonogram in the follow-up period of 3 to 28 months. On CT, cystic lesions became smaller size but did not disappear. Average CT numbers of the cyst were 8.75 +/- 3.83 before and 12.96 +/- 3.27 after ethanol instillation. The cystic wall became thicker. Caliceal distortion and/or pelvis compression by cystic lesions improved on IVP 2 to 3 days after ethanol instillation. The renal image on Tc-99m-DMSA scintigram showed morphological improvement and DMSA renal uptake rate increased slightly but significantly 2 to 4 weeks after ethanol instillation. There were no major complications with this procedure except for one case in which the tip of the catheter became stuck in the cyst and broke off when the catheter was removed. A slight local irritable pain was noticed in all cases. Half of the patients had hot flushes and/or somewhat drunken sense but these symptoms were only temporary. Antabuse phenomenon appeared in one case with concomitant use of a cephem antibiotics after ethanol instillation. This method of therapy is a safe non-surgical approach to treat renal cysts. 95% ethanol instillation in the cyst seems to prevent recurrence of cystic fluid.

Parathyroid cysts with primary hyperparathyroidism: report of a case.

Cysts of the parathyroid glands are uncommon, and, moreover functioning parathyroid cysts that cause primary hyperparathyroidism are rare. Herein is reported a 53-year-old female with primary hyperparathyroidism accompanied by 2 parathyroid cysts, in one of which adenoma was noticed. Forty-two cases of parathyroid cysts were found in the Japanese literature. Twelve of them were in the hyperparathyroid state, but infarction of the adenoma lead to cystic degeneration in most of such cases and so the cyst wall were lined with adenoma cells. In only 2 cases including our case were the cyst walls lined with cuboid cells and the adenoma evident in the wall. The pathogenesis of our case seems to be a common embryonic defect or dilatation of vestigial remnants rather than a degenerative change of the adenoma.

Inhibition of active sodium transport by cytochalasin B in rat jejunum in vitro.

The effects of cytochalasin B on electrophysiological properties and sodium transport in rat jejunum in vitro are described. Stripped paired rat jejunal segments were maintained in Ussing chambers with Leibovitz's (L-15) tissue culture medium bubbled with 100% oxygen. L-15 medium contains galactose as the only sugar, and an assortment of amino acids and cofactors to nourish the tissue. Electrophysiological parameters of short-circuit current (Isc) and transepithelial potential difference could be maintained for up to 4 h in control tissues. Upon application of cytochalasin B (20 micrograms/ml), on the mucosal side, Isc and potential difference fell within 1 h from 1.93 +/- 0.12 to 1.09 +/- 0.14 (mean +/- S.E.) muequiv./cm2 per h and from 5 to 2.5 mV. Tissue resistance remained unchanged at approx. 110 omega X cm2 for up to 4 h. 22Na net flux was 4.1 +/- 0.9 muequiv./cm2 per h during the last control period and fell to zero within 1 h after cytochalasin B treatment. Transmission electron micrographs revealed no gross morphological changes at this dose. Absorptive junctional morphology was apparently not altered by cytochalasin B treatment, a finding which was consistent with the stable transepithelial electrical resistance observed during exposure to this drug. Active sodium transport processes coupled to hexose, amino acid, and chloride movements are all possible in L-15 medium. However, following exposure to 20 micrograms/ml cytochalasin B, all net sodium transport is completely inhibited. The data are consistent with the hypothesis of a common regulator for active sodium transport processes which is modulated through structural changes in cytoskeletal organization.

Effects of cyclic AMP, ouabain and furosemide on ion transport in isolated canine gastric mucosa.

1. Cyclic AMP (10 mM), present in the serosal solution of isolated dog gastric mucosa, increased potential difference (p.d.), short-circuit current (ISC), net flux of Na+ from the mucosal to serosal side, and the unidirectional flux of K+ from the mucosal to serosal side. Cyclic AMP did not stimulate H+ or Cl- secretion. 2. Dibutyryl cyclic AMP (DBcAMP, 1 mM) or theophylline (2 mM), present in the serosal solution, stimulated H+ and Cl- secretion, decreased p.d., ISC and electrical resistance. These compounds had no effect on Na+ transport. The stimulatory effect of DBcAMP on H+ secretion was still present after pretreatment with cimetidine or atropine. 3. Ouabain abolished both the p.d. and ISC of the histamine-stimulated gastric mucosa. The mucosal to serosal flux of Na+ and the serosal to mucosal flux of Cl- were significantly decreased in the presence of ouabain. Ouabain caused an increase in the serosal to mucosal flux of K+ and high concentrations caused a significant reduction in H+ secretion. 4. Furosemide (10(-4) M) decreased p.d., ISC and net flux of Na+. Higher concentrations inhibited the net flux of Cl- from the serosal to mucosal side. 5. These results suggest that in isolated dog gastric mucosa, (1) both DBcAMP and theophylline may increase intracellular cyclic AMP to stimulate H+ and Cl- secretion, (2) cyclic AMP, outside the serosal membrane, stimulates active transport of Na+; in contrast, ouabain inhibits this active process predominantly, (3) the selective action of furosemide on Na+ transport indicates that Na+ and Cl- move via separate transport pathways across the serosal border.

Acute effects of N-methyl-N'-nitro-N-nitrosoguanidine on canine gastric mucosa.

The electrophysiological effects of the chemical gastric carcinogen N-methyl-N'-nitro-N-nitrosoquanidine (MNNG) were determined in an in vivo chambered canine stomach and in an in vitro canine gastric mucosal preparation. In the in vivo stomach, the topical application of 2.5 mg MNNG/ml decreased the transmural electrical potential difference, and the systemic blood pressure was essentially unchanged. In the in vitro preparation, exposure of the mucosal side of the isolated canine gastric mucosa to 0.25 and 2.5 mg MNNG/ml for 1 hour sequentially or exposure of the serosal side to 2.5 mg MNNG/ml for 2 hours inhibited net Na+ and Cl- fluxes. With longer duration, the undirectional fluxes of Na+ and Cl- increased, indicating an increase in permeability. These findings suggested that inhibition of active transport in the gastric mucosa may have an important function in the gastric carcinogenicity of MNNG.

Inhibition of ion transport by bile salts in canine gastric mucosa.

Studies were conducted with in vivo and in vitro canine stomach preparations. Instillation of 5, 10, and 20 mM bile salts in TES bufer (pH 7.4) into the nonsecreting stomach in vivo caused a progressive decrease in electrical potential difference (PD) and an increase in electrical resitance (R). The rate of acid secretion, determined by the pH-stat method in the histamine-stimulated stomach, decreased with 5 and 20 mM bile salts. Mucosal adenosine triphosphate (ATP) content of the nonsecreting or secreting stomach was reduced by bile salts. In vitro flux studies demonstrated that within the first hour after 1 mM bile salts were added to the mucosal side of the chamber, PD decreased, R increased, and net sodium transport decreased. In the second hour, unidirectional fluxes of sodium increased, indicating an increase in permeability of the gastric mucosa to sodium. These results demonstrate that the initial action of bile salts is inhibition of ion transport, which is followed by an increase in permeability.

Mechanism of action of aspirin on canine gastric mucosa.

Using an in vivo chambered canine stomach preparation, exposure of the gastric mucosa to 5, 10, and 20 mM aspirin(pH 3.0) resulted in a decrease in electrical potential difference (PD) and in an increase in resistance (R) within 30 min. In vitro, exposure of the mucosal side of the isolated canine gastric mucosa to 5, 10, and 20 mM aspirin (pH 3.0) for 1 h or of 1 mM aspirin (pH 3.0) for longer than 1 h resulted in marked permeability changes, i.e., increases in the undirectional fluxes of Na+ and Cl-, as well as inhibition of net ion fluxes. These concentrations of nonionized aspirin (pH 3.0) also reduced the R and PD. However, 1 mM aspirin (pH 3.0) or 20 mM ionized aspirin (pH 7.4) depresses the active transport of ion, increases R, but does not increase the ionic permeability. Mucosal adenosine triphosphate (ATP) content is reduced by mucosal instillation of aspirin (pH 3.0). These results demonstrate that the initial action of aspirin is inhibition of ion transport which is followed by an increase in permeability.