Strong formulations and cutting planes for designing digital data service networks

This paper deals with the problem of designing a least-cost digital data service (DDS) network that connects a given set of locations through digital switching offices with bridging capabilities. We present several alternative mixed 0–1 integer programming formulations and evaluate analytically their relative strengths by comparing their respective linear programming relaxations. By exploiting the structures inherent in a particularly strong formulation, we develop several classes of valid inequalities and cutting planes in order to tighten the initial formulation. For several problems of real-world data, computational results show that the strong formulation with valid inequalities and cutting planes generates a very tight lower bound (over 98% of the optimality) and so finds an optimal solution well within an acceptable time bound.     

Intrathecal granuloma complicating chronic spinal infusion of morphine. Report of three cases

OBJECTIVE: To assess the frequency of methotrexate (MTX)-induced pancytopenia in rheumatoid arthritis (RA). METHODS: A MEDLINE literature search was conducted to identify articles published during the last 15 years (1980-1995) that presented data on MTX-associated pancytopenia. Two case reports of our own experience are also presented. In addition, articles that examined risk factors associated with MTX-related pancytopenia were identified. RESULTS: A total of 70 patients with pancytopenia related to MTX therapy were identified (68 reported in the literature, 2 from our own experience). Sixty-one of the patients were described in published case reports, 7 patients were from 5 long-term prospective studies. In many of these cases, predisposing factors for the development of pancytopenia were described. The 5 long-term prospective studies reported toxicity data on patients who had been treated with MTX for at least 13 weeks. A total of 511 patients were included in the prospective trials, yielding an overall incidence of pancytopenia of 1.4% (7 of 511). Of the 70 cases reported, 12 patients died (17%). Most of them had impaired renal function, hypoalbuminemia, concurrent infection, and/or concomitant medication with more than 5 drugs. The minimal cumulative MTX dose leading to fatal pancytopenia was 10 mg, observed in one of our patients. CONCLUSION: Pancytopenia is not an uncommon side effect of low-dose pulse MTX therapy in RA. It can lead to serious complications, including death.     

Inhibitory action of YJA20379, a new proton pump inhibitor on Helicobacter pylori growth and urease

The use of an episiotomy for vaginal delivery is a controversial topic in modern obstetrics. If one is done, however, correct technique of perineal trauma repair is important. The usual episiotomy has traditionally been closed with interrupted suture. The use of a less reactive material, e.g. polyglycolic acid (Dexon), seem to be suitable for subcutaneous skin closure and beneficial in terms of acute postpartum discomfort and healing. The comparison of healing and patient comfort parameters between interrupted and subcutis polyglycolic acid suture used for episiotomy repair after delivery was done. Patients had follow-up during hospital stay, and two months after delivery a self administered questionnaire was sent to all women who participated, enquiring about perineal pain, resumption of sexual intercourse and cosmetics of suture line. Of 52 patients who had repair with interrupted suture, 21 were lost to follow-up. Of 65 gravidas who had repair with subcutis suture, 23 were lost to follow-up. At the 3rd day postpartum examination, patients with subcutis sutures had significantly better healing. An inflammatory process was present in 2 of 52 patients with interrupted sutures comparable with 1 of 65 in the subcutis group, and a gaping wound in 0 of 52 and 1 of 65, respectively. Recovery of function, measured by resumption of sexual activity by 8 weeks, was demonstrated in 5 of 31 patients with interrupted sutures versus 24 of 42 patients who had subcutis sutures. Episiotomy repair with subcutis polyglycolic acid (Dexon) offers significant advantages over traditional interrupted suture, both in terms of wound healing and resumption of sexual activity.     

Mutations in new cell cycle genes that fail to complement a multiply mutant third chromosome of Drosophila

We have simultaneously screened for new alleles and second site mutations that fail to complement five cell cycle mutations of Drosphila carried on a single third chromosome (gnu, polo, mgr, asp, stg). Females that are either transheterozygous for scott of the antartic (scant) and polo, or homozygous for scant produce embryos that show mitotic defects. A maternal effect upon embryonic mitoses is also seen in embryos derived from females transheterozygous with helter skelter (hsk) and either mgr or asp. cleopatra (cleo), fails to complement asp but is not uncovered by a deficiency for asp. The mitotic phenotype of larvae heterozygous for cleo and the multiple mutant chromosome is similar to weak alleles of asp, but there are no defects in male meiosis. Mutations that failed to complement stg fell into two complementation groups corresponding to stg and a new gene noose. Three of the new stg alleles are early zygotic lethals, whereas the fourth is a pharate adult lethal allele that affects both mitosis and meiosis. Mutations in noose fully complement a small deficiency that removes stg, but when placed in trans to certain stg alleles, result in late lethality and mitotic abnormalities in larval brains.