The formation of Ca++-dependent complexes of platelet membrane glycoproteins IIb and IIIa in solution as determined by crossed immunoelectrophoresis

Triton X-100 soluble proteins from 125I-labeled human platelets were studied by crossed immunoelectrophoresis employing a multispecific rabbit antibody raised against whole normal platelets. Emphasis was placed upon an analysis of immunoprecipitates containing 125I-labeled major membrane glycoproteins, and in particular, a prominent immunoprecipitate containing a glycoprotein antigen (s) previously designated as protein 16. SDS-polyacrylamide gel electrophoresis of protein 16 precipitated by a monospecific alloantibody. IgG L . . . , confirmed the presence of both glycoproteins IIb and IIIa. 125I-IgG L . . . , at concentration below that capable of precipitating protein 16 by itself, bound specifically to the precipitate containing protein 16 produced by the multispecific rabbit antibody. No other precipitates formed by the rabbit antibody contained either glycoprotein IIb or IIIa. When platelet proteins, incubated with optimum concentrations of ethylenediamine tetraacetic acid (EDTA) or ethyleneglycol bis (B- aminoethylether) NN1-tetraacetic acid (EGTA), were electrophoresed against the rabbit antibody, previously unobserved immunoprecipitates that contained either free glycoprotein IIb or free glycoprotein IIIa were detected. Upon readdition of excess Ca++, but not Mg++, to the same protein samples, a single immunoprecipitate containing both glycoproteins was once again observed. It is thus demonstrated that glycoproteins IIb and IIIa can form Ca++-dependent complexes (protein 16) in Triton X-100 extracts of normal platelets. The potential significance of the reversible association of these glycoproteins to normal platelet function is discussed.     

A locus for autosomal dominant anterior polar cataract on chromosome 17p

Inherited cataract is a clinically and genetically heterogeneous disease. Here we report the identification of a new locus for an autosomal dominant anterior polar cataract on the short arm of chromosome 17. To map this new locus we performed genetic linkage analysis with microsatellite markers in a four-generation pedigree. After exclusion of seven candidate loci for cataract, we obtained significant positive LOD scores for markers D17S849 (Z = 4.01 / theta = 0.05) and D17S796 (Z = 4.17 / theta = 0.05). Multipoint analysis gave a maximum LOD score of 5.2 (theta max = 0.06) between these two markers. From haplotype analysis, the cataract locus lies in the 13 cM interval between markers D17S849 and D17S796. This study provides the first genetic mapping of an autosomal dominant anterior polar cataract.      

Surface shield: device to reduce personnel radiation exposure

A simple device is described that can reduce personnel exposure from scatter radiation by up to 75%. The device consists of an oblong piece of shielding (0.75-mm lead equivalent) that is taped to the side of the patient during percutaneous renal stone removal and other interventional procedures. Contrary to other shields and barriers, this does not interfere with access to the patient. Scatter exposure data from phantom studies are presented and the rationale for surface shielding discussed.     

Selectivity of retrogasserian glycerol rhizotomy in the treatment of trigeminal neuralgia.

The possibility of obtaining a selective effect on different trigeminal branches by glycerol rhizotomy was studied in the treatment of trigeminal neuralgia. Transcutaneous electrical stimulation was used to quantify sensory impairment. An attempt was made to direct the neurotoxic effect by maintaining the patient's head in different positions during and after glycerol injection. The amount of glycerol injected varied according to the estimated size of the trigeminal cistern and/or to which branch that was involved. The study demonstrated a good selective effect on the ophthalmic branch, less selective on the maxillary, and a poorly selective effect on the mandibular branch. However, the clinical result following glycerol rhizotomy was equal regardless of the affected trigeminal branch.     

Comparison of weekly and daily incremental protocols of narrowband ultraviolet B phototherapy for psoriasis

BACKGROUND: Different protocols have been used for narrowband ultraviolet B (UVB) therapy, commonly used in the treatment of psoriasis; however, more effective and reliable protocols are still required. OBJECTIVE: The aim of this study was to compare the weekly and daily dose increment protocols of narrowband UVB phototherapy in psoriasis patients. METHODS: Thirty patients with plaque psoriasis underwent narrowband UVB treatment three times a week and 15 patients selected consecutively among these patients underwent a weekly (once in three treatments) dose increment whereas the remaining 15 patients underwent a daily dose increment. Patients were monitored for 10 weeks and evaluated by the Psoriasis Area Severity Index (PASI). RESULTS: When the two groups were evaluated according to median PASI scores prior to the treatment and during 10 weeks of treatment, there was no statistically significant difference between the groups (P > 0.05). During the treatment lasting for 10 weeks, four patients in the group with a weekly dose increment and three patients in the group with a daily dose increment recovered and no statistically significant difference was detected between the groups (P > 0.05). The groups were also evaluated according to the median cumulative dose. The median cumulative dose was higher in the group with a daily dose increment and the difference between the groups was statistically significant (P = 0.002). CONCLUSION: The application of daily dose increments was no better than that of weekly dose increments in narrowband UVB treatment for psoriasis. Therefore, although our results may need to be supported by large-series studies, we conclude that application of weekly dose increments with a lower cumulative dose having the same efficacy is preferred in narrowband UVB treatment of psoriasis.     

Sensory disturbance following percutaneous retrogasserian glycerol rhizotomy

Nineteen patients with tic douloureux were treated with glycerol injection in the trigeminal cistern. Facial sensibility was measured with an electrical stimulator one day before and one day after the glycerol treatment. The thresholds for perception and pain, and the maximal pain tolerance rose by about 50% (p less than 0.01, 0.01, and 0.001, respectively). The hypaesthesia and hypalgesia were most marked just below the eye, whereas the mandibular division showed only slight sensory impairment. In 13 patients a follow-up sensimetry study was done 1-7 months after surgery. Thirteen patients became completely free of pain and one almost completely free from pain (74%). Two had no pain relief. Twelve patients had no subjective complaints of the treatment. Three reported on dysaesthesiae (16%) over the previously painful area. Seven patients (37%) had subjective sensations of diminished or altered sensibility: numbness and hypalgesia in the face. Corneal hypaesthesia was recorded in ten patients (53%). Glycerol has a non-specific neurotoxic effect which is equal for tactile and nociceptive fibres. Sensory impairment may be a conditio sine qua non for a good clinical result.     

Thrombosed synthetic hemodialysis access fistulas: failure of fibrinolytic therapy

Seven episodes of acute thrombosis occurring in five patients with polytetrafluoroethylene dialysis fistulas were treated with local infusions of low-dose streptokinase. Bleeding from previous dialysis puncture sites necessitated stopping the infusion in six out of seven patients, although in one of these six, the graft reopened. The seventh patient had never been dialyzed through the graft and thrombolysis was achieved without incident. Surgery was avoided in only one patient. The authors contend that in these patients the risks of fibrinolytic therapy outweigh the benefits. Surgical thrombectomy, coupled with intraoperative angiography and possible angioplasty, is the preferred method of treating these patients. Venography prior to the creation of the fistula helps the surgeon avoid diseased vessels and may avert early failure of the fistula.