First Measurement of a Long-Lived π

The adapted DIRAC experiment at the CERN PS accelerator observed for the first time long-lived hydrogenlike π^{+}π^{-} atoms, produced by protons hitting a beryllium target. A part of these atoms crossed the gap of 96 mm between the target and a 2.1 µm thick platinum foil, in which most of them dissociated. Analyzing the observed number of atomic pairs, n_{A}^{L}=436_{-61}^{+157}|_{tot}, the lifetime of the 2p state is found to be τ_{2p}=(0.45_{-0.30}^{+1.08}|_{tot})×10^{-11} s, not contradicting the corresponding QED 2p state lifetime τ_{2p}^{QED}=1.17×10^{-11} s. This lifetime value is three orders of magnitude larger than our previously measured value of the π^{+}π^{-} atom ground state lifetime τ=(3.15_{-0.26}^{+0.28}|_{tot})×10^{-15} s. Further studies of long-lived π^{+}π^{-} atoms will allow us to measure energy differences between p and s atomic states and so to discriminate between the isoscalar and isotensor ππ scattering lengths with the aim to check QCD predictions.

A biopsy procedure for determining filet and predicting whole-fish mercury concentration.

Although mercury contamination of fish is a widespread phenomenon, its regional evaluation is hindered by the reluctance of permitting agencies to grant collection permits, problems in securing adequate freezer space, and time to process whole, large fish or filets. We evaluated mercury concentrations in 210 filet biopsies from 65 sites in 12 western states relative to whole-body mercury concentration in the same fish. We found a highly significant relationship (r(2) = 0.96) between biopsy and whole-fish mercury concentrations for 13 piscivorous and nonpiscivorous fish species. We concluded that relative to conventional fish-tissue sampling and analysis procedures for whole fish or filets, the biopsy procedure for mercury in fish tissue is nonlethal, less cumbersome, more likely to be permitted by fisheries agencies, and a precise and accurate means for determining both filet and whole-fish mercury concentrations.

A retrospective study on chemical and radioactive synovectomy in severe haemophilia patients with recurrent haemarthrosis.

Between 1970 and 1994, 116 chemical and 90 radioactive synovectomies were performed in 107 patients with severe haemophilia and two with type 3 von Willebrand's disease. The products used were osmic acid (OA) in 100 cases, 90-Yttrium in 35 cases, 186-Rhenium in 48, 169-Erbium in two, hexacetonide triamcinolone in 16 and radioactive gold in five cases. The use of radioactive colloids is not allowed in France in patients under 15 years of age. Twenty-nine patients had more than one synovectomy per joint. All patients were evaluated for 6 months post-synovectomy, using both a clinical and a radiological score. Six months after synovectomy, a good or excellent result was obtained for 81% of the joints treated with isotopes, compared with 44% of those treated with OA, P<0.001. This superiority of isotopes over osmic acid was still observed after 6 months for the 89 joints that were re-evaluated, with follow-up ranging from 1 to 9 years. It was possible to calculate a radiological score in 84 cases. With OA the best results were from the joints with the lowest scores pre-synovectomy (<7). No correlation could be established between the clinical and the radiological scores, due to the small size of the sample. In summary: (1) chemical and radioactive synovectomy are simple and safe procedures for haemophilic arthropathy, (2) in our series, after 6 months the efficacy of isotopic synovectomy was greater than that of chemical synovectomy, and this benefit seems to persist after 6 months, and up to 9 years in the group of patients with longer-term follow-up.

Nonsurgical synovectomy in the treatment of arthropathy in Von Willebrand's Disease.

Von Willebrand's disease is the most common inherited bleeding disorder, with an overall prevalence in the general population of 0.8% to 1.3%. Hemarthrosis occurs mainly in the severest forms of the disease (type III), with a frequency of 3.5% to 11%, and can cause severe arthropathy similar to that seen in hemophilia. We retrospectively reviewed our experience with nonsurgical synovectomy in the treatment of recurrent hemarthrosis with arthropathy in patients with von Willebrand's disease. Four of our six patients had type III disease and the remaining two had type II disease. The age range was 13 to 63 years. The frequency of hemarthrosis prior to synovectomy was one to four per month. One (n = 2) or both (n = 1) knees were treated in 4 cases, one (n = 1) or both (n = 1) ankles in 3 cases and an elbow in one case. We used yttrium 90 in a dose of 5 mCi for one knee, rhenium 186 in a dose of 2 mCi for two ankles and the elbow and osmic acid for two knees and one ankle. Clinical and radiological results were evaluated six months after synovectomy using the World Federation of Hemophilia score. Radiologic lesions remained stable and clinical manifestations improved in every case (p < 0.05). Five patients achieved a complete remission. Safety was satisfactory. The clinical efficacy of synovectomy done, using radiocolloids or osmic acid in arthropathy due to von Willebrand's disease, seems similar to that in hemophilia.

Lymphadenitis in Sowda.

Sowda is a form of onchocerciasis in Yemen characterized by unilateral dermatitis of one limb, with enlargement of the regional lymph nodes. Previous pathologic studies of lymph nodes from cases of Sowda describe only follicular hyperplasia without microfilariae in the lymph nodes. This contrasts with African onchocerciasis, where the lymph nodes tend to be atrophic and microfilariae are usually present. In the present report, a case of Sowda with microfilariae in the lymph nodes is described and the implications of this finding are discussed.

Artificial rearing of rat pups with a protein-enriched formula.

Neonatal Long-Evans hooded rat pups were assigned to one of three groups: 1) pups normally reared, 2) pups implanted with intragastric cannulas and artificially reared with a common milk replacement formula, 3) pups implanted with intragastric cannulas and artificially reared with a protein-enriched milk formula. Daily body weights were recorded, as were the ontogeny of various reflexes. On day 18, the animals were behaviorally tested and then killed. There were no differences among the three groups in daily body weights, nor in the ontogeny of reflexive behavior. There were no differences in the wet weights of caudal brain sections, but the normally reared animals had significantly larger rostral brain sections than either artificially reared group. While cerebella of normally reared animals were significantly larger than those of the two artificially reared groups, there was a significant trend towards more normal cerebellar weights with the addition of protein in the formula of artificially reared animals. Behavioral tests indicated that the animals artificially reared have significantly different behavior than normally reared animals. However, compared to animals artificially reared using a common milk formula, animals artificially reared with additional protein in their formula behave more like normally reared animals.