A plethora of carbene interconversions on the C(5)H(4)S energy surface: a computational study.

The potential energy surface for the reaction of atomic carbon with thiophene has been studied computationally. Intermediates which are energetically viable include the 2- and 3-thienylcarbenes 8 and 11, thiacyclohexa-3,5-dien-2-ylidene, 10, and thiacyclohexa-2,3,5-triene, 6. In accord with experimental data, 6 and 8 are in equilibrium. The lowest-energy pathway for rearrangement of 6 to 8, which is endothermic by 14.5 kcal/mol, involves ring opening to Z-2-penten-4-ynthial which then recloses to carbene 8. A 1,4 addition of C across the diene system in thiophene generates an ylid which rearranges with little or no barrier to cyclopentadienethione, the global minimum on this potential energy surface.

Modified ice study: a phase II study of an intensive, modified ICE regimen (ifosfamide, carboplatin and etoposide) in patients with better prognosis, small cell lung cancer.

A total of 30 with good prognosis small cell lung cancer were treated with a modified 'ICE' (ifosfamide, carboplatin and etoposide) chemotherapy regimen in an attempt to achieve a high response rate with less toxicity than is seen with the full 'ICE' regimen. This was given every 4 weeks for a maximum of six cycles. In total 25 patients (83%, 95% CI (70-97%)) experienced a partial or complete response at some stage of their treatment. Of these patients, 12 (40%, 95% CI (22-58%)) showed a complete response. A total of 19 patients (63%) had to have their dose reduced and/or delayed at some point due to toxicity. Nadir blood counts showed that 19 patients (63%, 95% CI (46-81%)) had WHO grade 3 or 4 thrombocytopenia, and 24 (86%, 95% CI (73-99%)) had grade 3 or 4 neutropenia. A total of 17 patients (53%) completed six cycles of chemotherapy. In total 3 patients died during treatment all due to treatment-related complications. Median survival was 12.6 months (95% CI (11.6, 14.7 months)). Nausea, vomiting, dysphagia, activity, mood and overall condition, as recorded using daily diary cards, were worse at the beginning of each chemotherapy cycle. Both response rates and survival were clinically acceptable. However, neutropenia and thrombocytopenia, although reduced from rates reported with the full ICE regimen, were still high. A prospective randomised controlled trial is now needed to assess this regimen in more detail.

Prognosis in lung cancer: physicians' opinions compared with outcome and a predictive model.

BACKGROUND: Although the study of prognostic factors in small cell lung cancer has reached the stage where they are used to guide treatment, fewer data are available for non-small cell lung cancer. Although correct management decisions in non-small cell lung cancer depend upon a prognostic assessment by the supervising doctor, there has never been any measurement of the accuracy of physicians' assessments. METHODS: A group of consecutive patients with non-small cell lung cancer was studied and the predictions of their physicians as to how long they would survive (in months) was compared with their actual survival. A prognostic index was also developed using features recorded at the patients' initial presentation. RESULTS: Two hundred and seven consecutive patients diagnosed and managed as non-small cell lung cancer, who did not receive curative treatment for their condition, were studied. Of the 196 patients whose date of death was known, physicians correctly predicted, to within one month, the survival of only 19 patients (10%). However, almost 59% of patients (115/196) had their survival predicted to within three months and 71% (139/196) to within four months of their actual survival. Using Cox's regression model, the sex of the patient, the activity score, the presence of malaise, hoarseness and distant metastases at presentation, and lymphocyte count, serum albumin, sodium and alkaline phosphatase levels were all identified as useful prognostic factors. Three groups of patients, distinct in terms of their survival, were identified by the use of these items. When the prediction of survival made by the physician was included as a prognostic factor in the original model, it was shown to differentiate further between the group with a poor prognosis and the other two groups in terms of survival. CONCLUSIONS: Physicians were highly specific in identifying patients who would live less than three months. However, they had a tendency to overestimate survival in these patients, failing to identify almost half the patients who actually died within this time. Both the physicians and the prognostic factor model gave similar performances in that they were more successful in identifying patients who had a short time to survive than those who had a moderate or good prognosis. Physicians appear to use information not identified in the prognostic factor analysis to reach their conclusions.

Preemptive oral treatment with sumatriptan during a cluster period.

This multinational, multicenter, randomized, double-blind, placebo-controlled study in 169 patients investigated the effect of a 7-day period of preemptive treatment with oral sumatriptan (100 mg tid) on the frequency and severity of cluster headache attacks occurring during an established cluster headache period. Safety and tolerability were also assessed. Cluster headache patients who were not taking prophylactic medication and had experienced seven or more attacks in the preceding observation week, treated a cluster headache attack at home with subcutaneous sumatriptan 6 mg using an autoinjector device. Patients were then randomized to take sumatriptan 100 mg or placebo at 8-hourly intervals for a 7-day period. Cluster headaches occurring during this period could be treated 5 minutes after onset with rescue medication (100% oxygen or simple analgesics). Diary cards were used to record details of the cluster headache pattern during the observation and study treatment weeks. Preemptive oral treatment with sumatriptan 100 mg tid for 7 days did not produce a significant reduction in the number or severity of cluster headache attacks occurring during an established cluster headache period. Oral treatment with sumatriptan 100 mg tid over a 7-day period was not associated with an increased or altered adverse event profile from that previously reported.

Subcutaneous sumatriptan during the migraine aura. Sumatriptan Aura Study Group.

This double-blind, placebo-controlled, multicenter, parallel-group study assessed whether subcutaneous sumatriptan administered during the migraine aura would prolong or modify the aura and prevent or delay development of the headache. One hundred seventy-one patients (88 receiving 6 mg sumatriptan, 83 receiving placebo) treated a single attack of migraine with typical aura at home, by self-injection. The median duration of aura following the first injection was 25 minutes for the sumatriptan group and 30 minutes for the placebo group (NS). The aura symptom profile was similar for the two treatment groups. The proportion of patients who developed a moderate or severe headache within 6 hours after dose administration was similar in the two groups--68% among those receiving sumatriptan and 75% among those receiving placebo (NS). Sumatriptan given during the aura did not prolong or alter the nature of the migraine aura and did not prevent or significantly delay headache development.

The formation of amino acid precursors in the reaction of atomic carbon with water and ammonia at 77 K.

When atomic carbon is condensed on a surface at 77 K containing ammonia and water, glycine, N-methylglycine, alanine, beta-alanine, aspartic acid and serine are generated. It is postulated that these reactions may mimic those which occur when an extraterrestrial carbon atom condenses on a frozen surface coated with water and ammonia and may provide a route to extraterrestrial amino acids. Experiments designed to elucidate the mechanisms of amino acid formation under these conditions have been carried out.

The architecture of actin filaments and the ultrastructural location of actin-binding protein in the periphery of lung macrophages.

A highly branched filament network is the principal structure in the periphery of detergent-extracted cytoskeletons of macrophages that have been spread on a surface and either freeze or critical point dried, and then rotary shadowed with platinum-carbon. This array of filaments completely fills lamellae extended from the cell and bifurcates to form 0.2-0.5 micron thick layers on the top and bottom of the cell body. Reaction of the macrophage cytoskeletons with anti-actin IgG and with anti-IgG bound to colloidal gold produces dense staining of these filaments, and incubation with myosin subfragment 1 uniformly decorates these filaments, identifying them as actin. 45% of the total cellular actin and approximately 70% of actin-binding protein remains in the detergent-insoluble cell residue. The soluble actin is not filamentous as determined by sedimentation analysis, the DNAase I inhibition assay, and electron microscopy, indicating that the cytoskeleton is not fragmented by detergent extraction. The spacing between the ramifications of the actin network is 94 +/- 47 nm and 118 +/- 72 nm in cytoskeletons prepared for electron microscopy by freeze drying and critical point drying, respectively. Free filament ends are rare, except for a few which project upward from the body of the network or which extend down to the substrate. Filaments of the network intersect predominantly at right angles to form either T-shaped and X-shaped overlaps having striking perpendicularity or else Y-shaped intersections composed of filaments intersecting at 120-130 degrees angles. The actin filament concentration in the lamellae is high, with an average value of 12.5 mg/ml. The concentration was much more uniform in freeze-dried preparations than in critical point-dried specimens, indicating that there is less collapse associated with the freezing technique. The orthogonal actin network of the macrophage cortical cytoplasm resembles actin gels made with actin-binding protein. Reaction of cell cytoskeletons and of an actin gel made with actin-binding protein with anti-actin-binding protein IgG and anti-IgG-coated gold beads resulted in the deposition of clusters of gold at points where filaments intersect and at the ends of filaments that may have been in contact with the membrane before its removal with detergent. In the actin gel made with actin-binding protein, 75% of actin-fiber intersections labeled, and the filament spacing between intersections is consistent with that predicted on theoretical grounds if each added actin-binding protein molecule cross-links two filaments to form an intersection in the gel.(ABSTRACT TRUNCATED AT 400 WORDS)