ALGORITHMIC SYNTHESIS OF GENERAL NON-SHARP SIMPLE DISTILLATION COLUMN SEQUENCES

An algorithmic approach was used to select recoveries for non-sharp sequence designs. Simple distillation columns were employed. The non-key component distribution was modeled using the Fenske equation. The combination of producing impure products and allowing non-key component distribution, results in a large search space. With this large search space size and software limitations, five problems were solved (see summary table in the Design Examples sub-section). The optimal non-key component distribution was found to be significant but not necessarily maximal. Parallel processing was selected as optimal in contrast to the more traditional sequential processing.     

Clinical trial of retrograde warm blood reperfusion versus standard cold topical irrigation of transplanted hearts

BACKGROUND: A prospective, randomized clinical study involving 34 patients undergoing heart transplantation compared myocardial preservation of donor hearts maintained with continuous reperfusion with retrograde warm blood cardioplegia during surgical implantation versus the standard cold topical irrigation. METHODS: Hearts in both groups were arrested with a standard crystalloid solution and maintained in a cold saline solution during transportation. In the retrograde group, cardioplegia was administered through a catheter in the coronary sinus during surgical implantation. An average of 471 +/- 30 mL of hyperkalemic crystalloid solution diluted 1:4 in warm blood from the oxygenator was infused. In the standard group, the heart was kept cold by topical irrigation of cold saline solution and was reperfused only when the ascending aorta was unclamped. RESULTS: Preoperative characteristics of donors and recipients were similar in the two cohorts. Ischemic time average 139 +/- 12 minutes in the retrograde group compared with 130 +/- 11 minutes in the standard group (p = 0.57). Cardiopulmonary bypass time averaged 89 +/- 4 minutes in the retrograde group and 110 +/- 12 minutes in the standard group (p = 0.12). Defibrillation at reperfusion was performed in 4 patients (4/17, 24%) in the retrograde group and 12 patients (12/18, 67%) in the standard group (p = 0.01). There were no deaths in the retrograde group (0/17), whereas in the standard group, 3 patients (3/17) died of early graft failure (p = 0.11). Four early graft failures occurred in the standard group (p = 0.06). Two patients (2/17, 12%) were weaned from bypass with ventricular assist devices in the standard group. The number of subendocardial necrotic cells in the first two weekly endomyocardial biopsy specimens averaged 2.7 +/- 0.8 cells/mm2 in the retrograde group and 5.9 +/- 2.4 cells/mm2 in the standard group (p = 0.12). CONCLUSIONS: Retrograde warm blood reperfusion appears to improve the initial recovery of transplanted hearts. The technique is easy to use and may be a useful approach to graft protection during surgical implantation.     

Organization of the genes encoding p-aminobenzoic acid synthetase from Streptomyces lividans 1326

The selective 5HT3 antagonist tropisetron was studied in 91 outpatients meeting DSM-III criteria for Generalized Anxiety Disorder. Following a placebo washout period of up to 1 week, one of three active treatments (tropisetron 0.5 mg, 5 mg, or 25 mg daily) or placebo was given for a further 3 weeks. After 7 days treatment termination rates due to inefficacy showed a statistically significant dose-related therapeutic effect of tropisetron. Similar effects were seen on the Hopkins Symptom Check List total score and the Global Impression Scale. The Hamilton Anxiety Scale showed a similar trend which, however, failed to reach statistical significance. At day 21 tropisetron showed significant dose-dependent effects on all anxiety-related outcome measures. The incidence of adverse events was low and the severity generally mild. Most frequent complaints were headache, nausea, constipation and nervousness. Laboratory tests and physical examination performed at baseline and study end showed no significant treatment effects.     

Hypophosphatemia and the development of rickets in osteopetrotic (op/op) mice

Our previous work has shown that op/op mice hyperabsorb dietary calcium in the vitamin D-deficient state and shunt that calcium into bone. Under these conditions, the op/op mice are hypocalcemic. The purpose of this study was to examine calcium metabolism and bone mineralization in vitamin D-deficient op/op mice. First, the op/op mice and their normal littermates were placed on a vitamin D-deficient, low phosphorus diet to limit bone mineralization. Under these circumstances, op/op mice survived, even when calcium was also removed from the diet. If the diet contained phosphate, op/op mice died from hypocalcemic tetany when calcium was also removed from the diet. Furthermore, serum calcium levels became similar to wild type in the op/op mice administered the vitamin D-deficient, low phosphorus diet, and op/op mice were able to increase serum calcium in response to 1,25-dihydroxyvitamin D3. The op/op mice developed rickets when their serum phosphorus level was too low to support bone mineralization. The op/op mice became hypophosphatemic on regimens in which normal mice were able to maintain normal serum phosphorus levels. It appears that the op/op mouse simply requires a higher dietary calcium and phosphorus level to prevent rickets and hypocalcemic tetany since the bone is not available as a source of these minerals. However, the ability of the op/op mouse to mineralize bone at low serum calcium and phosphorus levels remains unexplained.     

Allergic rhinoconjunctivitis treated with intramuscular injection of glucocorticoid

Effects and side effects of injectable depot steroid in the treatment of allergic rhinoconjunctivitis (hay fever) are described. A few controlled studies have shown injectable steroids to be superior to the effect of placebo and locally applied steroid. Over a period of 10 years from 1984-95 only 26 registered side effects were reported to the central Danish register for side effects of drugs (Laegemiddelstyrelsens Bivirkningsregister). Only eight concerned subcutaneous atrophy and in two cases the cutaneous changes persisted. Based on registration of number of treatments in the county of Funen 1996, it is estimated that the use of injectable depot steroids for treatment of hay fever accounts for about 535,000 DDD (defined daily doses corresponding to about 33,000 treatments per year). We conclude that the use of injectable corticosteroids in the treatment of hay fever is common and effective and side effects are very rare. However, injectable corticosteroids should only be used when conventional treatment is not sufficient to control symptoms.     

Effect of spinal cord transection on N-methyl-D-aspartate receptors in the cord

Spinal cord injury can lead to an exaggeration of transmission through spinal pathways, resulting in muscle spasticity, chronic pain, and abnormal control of blood pressure and bladder function. These conditions are mediated, in part, by N-methyl-D-aspartate (NMDA) receptors on spinal neurons, but the effects of cord injury on the expression or function of these receptors is unknown. Therefore, antibodies to the NMDA-R1 receptor subunit and binding of [3H]MK-801 were used to assess NMDA receptors in the spinal cord. Receptor density in rats with intact spinal cords was compared to that in rats 1 and 2 weeks after spinal cord transection (SCT) at the mid-thoracic level. At 1 and 2 weeks after SCT, [3H]MK-801 binding was reduced in most laminae in cord segments caudal to the injury, whereas no decrease in amount of R1 subunit immunoreactivity was observed. No significant changes in [3H]MK-801 binding and NMDA-R1 immunoreactivity could be seen rostral to the transection. Since [3H]MK-801 binding requires an open ion channel, the discrepancy between [3H]MK-801 binding and immunocytochemistry may indicate a loss of functional receptors without a consistent change in their total number. Therefore, the exaggerated reflexes that are well established in rats 2 weeks after cord injury must be mediated by a mechanism that withstands attenuation of NMDA receptor function.