A composite method for the determination of the chirality of single walled carbon nanotubes

An approach to the unambiguous determination of the conformation of individual single walled nanotubes utilizing high-resolution transmission electron microscopy and digital image processing is described. The exit plane wave of single walled nanotubes restored from a focal series of images is used in a stepwise characterization procedure utilizing both the phase of the real space restoration and its Fourier transform. A combination of these complementary characterization steps yields an accurate measurement of the chiral vector for an individual nanotube.

Comminuted fracture of the talus not visible on the initial radiograph

Fractures of the talus are rare injuries and fractures of the body of the talus are particularly rare. Diagnosis of these fractures is also difficult as initial radiographs may be normal, particularly with osteochondral talar dome fractures. Long term morbidity is common after fractures of the talus. A case is presented of a patient with a comminuted fracture of the body of the talus with non-diagnostic initial standard ankle radiographs. Accident and emergency doctors should be aware of this injury, and be suspicious that patients with an appropriate mechanism of injury and pronounced pain may require further investigation despite normal standard ankle radiographs, as an occult fracture of the talus may be present.

A phase II trial of edatrexate, vinblastine, adriamycin, cisplastin, and filgrastim (EVAC/G-CSF) in patients with non-small-cell carcinoma of the lungs: a North Central Cancer Treatment Group Trial

Edatrexate is an antifolate agent with improved in vitro antineoplastic activity as compared with methotrexate. A Mayo phase I trial of edatrexate (E), vinblastine (V), doxorubicin (Adriamycin) (A), cisplatin (C), and filgrastim (GCSF), (EVAC-GCSF) showed promising antineoplastic activity in non-small-cell lung cancer (NSCLC) (Colon-Otero G, et al. Cancer J Sci Am 1997;3:297-302) leading to a phase II trial of this regimen, the results of which are reported here. A total of 34 patients with stage IIIB or IV measurable or evaluable NSCLC were entered in this North Central Cancer Treatment Group phase II study. Treatment consisted of edatrexate 100 mg/m2 intravenously on day 1 and cisplatin 30 mg/m2/d on day 1 and day 2 followed by vinblastine 3 mg/m2 intravenously and doxorubicin 30 mg/m2 intravenously on day 2. Filgrastim was given at 300 microg subcutaneously daily from day 4 to day 18 or until an absolute neutrophil count of 2,000/mm3 or more was obtained. Cycles were repeated every 21 days until either progression or the development of intolerable toxicity. Sixteen of 34 evaluable patients responded to therapy, for a response rate of 47.1% with a 95% CI of 30.3% to 63.8%. Median time to disease progression was 132 days, median survival time was 219 days, and the estimated 1-year survival was 41.2% (95% CI of 27.6-61.5%). The EVAC/G-CSF regimen has significant antineoplastic activity as seen by the response rates for patients with NSCLC. However, this study had significant myelosuppressive toxicity; 56% patients had grade III or higher leukopenia with three treatment-related deaths observed. In addition, Quality of Life assessments indicate that patients experienced an overall decline in quality of life during the course of treatment. These mitigating factors need to be considered regarding further evaluation of this regimen in this patient population.

Deletion of the cnxE gene encoding the gephyrin-like protein involved in the final stages of molybdenum cofactor biosynthesis in Aspergillus nidulans

The Aspergillus nidulans cnxE gene, required for molybdenum cofactor biosynthesis, was isolated by functional complementation of an Escherichia coli mogA mutant strain. The deduced CnxE polypeptide consists of two domains which display similarity to the E. coli proteins MoeA and MogA, respectively, separated by a putative hinge region of around 58 amino acid residues which is notably histidine rich. A deletion mutant lacking the entire cnxE gene, including both MoeA-like and MogA-like domains, was identified. Compared to the wild type, a small increase in the intermediate precursor Z was observed in the deletion strain but was significant only under conditions in which the molybdoenzyme nitrate reductase was induced. Elevated levels of the pathway intermediate molybdopterin were found both under nitrate reductase-inducing and non-inducing conditions in the deletion mutant compared to the wild type. This increase is in contrast to previous results for cnxABC, cnxF, cnxG, and cnxH mutants, in which the levels of molybdopterin were substantially reduced, and therefore supports previously published classical genetic and biochemical studies that indicated that the CnxE protein is likely to be involved in the final stages of molybdenum cofactor biosynthesis. We have found no evidence during our chemical analysis for any involvement of this protein in the intermediate section of the molybdenum cofactor biosynthetic pathway (i.e. in the synthesis of molybdopterin from precursor Z), as has been suggested previously for E. coli MoeA. The 2.5-kb cnxE transcript is not abundant and appears to be expressed constitutively.

Phase I trial of gemcitabine and CPT-11 given weekly for four weeks every six weeks

BACKGROUND

Our previous studies have shown that the in vitro cytotoxicity of gemcitabine and SN-38, the active metabolite of irinotecan (CPT-11), is synergistic in human tumor cell lines.

PATIENTS AND METHODS

Twenty-four patients with solid tumors, refractory to standard chemotherapy or for whom no effective therapy existed (age range 31-74; 7 female, 17 male; ECOG PS 0 = 12, 1 = 11, 2 = 1), received gemcitabine and CPT-11 weekly for four weeks out of every six weeks. Fifty courses of treatment (median 2, range 1-8) were given through five dose levels of gemcitabine/CPT-11 (600/75, 800/75, 800/100, 1000/100, 1000/125 mg/m2).

RESULTS

Grade 3 and 4 neutropenia occurred in eight and two patients, respectively. Grade 3 and 4 thrombocytopenia occurred in one and three patients, respectively. Hematologic toxicity resulted in > or = 2 missed doses of treatment in two out of six patients and was therefore dose limiting at gemcitabine 1000 mg/m2 and CPT-11 125 mg/m2. Grade 3 and 4 diarrhea occurred in two and one patients, respectively. Other moderate non-hematologic toxicities included alopecia, anorexia, fatigue, nausea, vomiting, and weight loss.

CONCLUSIONS

The maximum tolerated dose for this study recommended for phase II testing is gemcitabine 1000 mg/m2 and CPT-11 100 mg/m2. A partial response was seen in transitional cell carcinoma.

Phase I trial of sequential administration of raltitrexed (Tomudex) and 5-iodo-2'-deoxyuridine (IdUrd)

Raltitrexed (Tomudex) is a specific inhibitor of thymidylate synthase with clinical activity in colorectal cancer. The combination of raltitrexed and 5-iodo-2'-deoxyuridine (IdUrd, a cytotoxic pyrimidine analog) resulted in increased IdUrd incorporation into DNA and exhibited in vitro synergism against colon and bladder human carcinoma cell lines. We designed a phase I trial to determine the MTD, pharmacokinetics, and biologic effects of escalating doses of the combination of IdUrd given as a 24-hour infusion after a raltitrexed 15-minute infusion every three weeks. Thirty-four patients received 95 courses of raltitrexed and IdUrd at doses ranging from raltitrexed 1 mg/m2 and IdUrd 750 mg/m2 to raltitrexed 2.5 mg/m2 and IdUrd 10,400 mg/m2. The median number of cycles administered was 2 (range 1-10). Dose limiting hematologic toxicity occurred at doses of raltitrexed 2.5 mg/m2 and IdUrd 10,400 mg/m2. In addition, we determined the mean plasma concentrations C(SS) of IdUrd, the iodouracil level at 22 hours and the IdUrd clearance. Raltitrexed did not appear to affect the pharmacokinetics of IdUrd in the dose range tested. The recommended phase II dose is raltitrexed 2 mg/m2 and IdUrd 10,400 mg/m2 repeated every three weeks. Evidence of potential antitumor activity was observed: 1 patient (with colon cancer) had a partial response while 15 others had stable disease.

An examination of psychometric properties of the mini-mental state examination and the standardized mini-mental state examination: implications for clinical practice

The Mini-Mental State Examination (MMSE), as developed by Folstein, Folstein, and McHugh (1975), is the most widely used of cognitive screening tools. An examination of the psychometric properties of the MMSE seems warranted because the accurate and comprehensive assessment of mental status can yield profound implications for the quality of life of cognitively impaired older adults (Danner, Beck, Heacock, & Modlin, 1993). In clinical practice, nurses must not only use a valid and reliable screening tool for assessing cognitive impairment, but they must also assess the physical disabilities that may affect client performance and, hence, the cognitive impairment score. The purpose of this study is to examine the psychometric properties of the MMSE in comparison to a more standardized tool and to identify implications of the tool for clinical practice.

Physician-owned imaging centers: the future is now

Although changes in the health care arena have made inroads in physicians' autonomy and reimbursement, new opportunities have also emerged. We describe basic principles that can help develop freestanding, independent, physician-owned imaging centers offering cost-competitive, high-quality services. To succeed, physicians must invest in their companies, think strategically, pursue clear objectives, examine data and be willing to assume a certain amount of risk. Marketing their services is critically important and requires careful attention to patients and referring physicians. We have found that, while these challenges are large, the rewards are substantial.

Discrete atom imaging of one-dimensional crystals formed within single-walled carbon nanotubes

The complete crystallography of a one-dimensional crystal of potassium iodide encapsulated within a 1.6-nanometer-diameter single-walled carbon nanotube has been determined with high-resolution transmission electron microscopy. Individual atoms of potassium and iodine within the crystal were identified from a phase image that was reconstructed with a modified focal series restoration approach. The lattice spacings within the crystal are substantially different from those in bulk potassium iodide. This is attributed to the reduced coordination of the surface atoms of the crystal and the close proximity of the van der Waals surface of the confining nanotube.

Evolution of a glucose-regulated ADH gene in the genus Saccharomyces

To determine when a glucose-repressed alcohol dehydrogenase isozyme and its regulatory gene, ADR1, arose during evolution, we surveyed species of the genus Saccharomyces for glucose-repressed ADH isozymes and for ADR1 homologues. Glucose-repressed ADH isozymes were present in all species of Saccharomyces sensu strictu and also in Saccharomyces kluyveri, the most distant member of the Saccharomyces clade. We cloned and characterized ADH promoters from S. bayanus, S. douglasii, and S. kluyveri. The ADH promoters from S. bayanus and S. douglasii had conserved sequences, including upstream regulatory elements, and an extended polydA tract. The expression of a reporter gene driven by the S. bayanus promoter was glucose-repressed and dependent on the major activator of transcription, ADR1, when it was introduced into S. cerevisiae. One S. kluyveri promoter was also glucose-repressed and ADR1-dependent in S. cerevisiae. The other S. kluyveri ADH promoter was expressed constitutively and was ADR1-independent. Although showing little sequence conservation with the S. cerevisiae ADH2 promoter, the glucose-repressed S. kluyveri promoter contains numerous potential binding sites for Adr1. The glucose-repressed ADH from S. kluyveri is a mitochondrial isozyme most closely related to S. cerevisiae ADHIII. ADR1 homologues from S. douglasii and S. paradoxus contain a trinucleotide repeat encoding polyAsn that is lacking in S. cerevisiae and S. bayanus. No ADR1 homologue could be detected in S. kluyveri, suggesting that the potential for Adr1 regulation may have arisen first, before ADR1 evolved.

Pilot evaluation of venlafaxine for the treatment of hot flashes in men undergoing androgen ablation therapy for prostate cancer

PURPOSE

Hot flashes may be a significant clinical problem in men undergoing androgen deprivation therapy with gonadotropin releasing hormone analogues, oral antiandrogens and/or surgical bilateral orchiectomy. Anecdotal information suggests that a low dose of the relatively new antidepressant venlafaxine may abrogate this clinical problem. We developed the current pilot trial to investigate further whether venlafaxine alleviates hot flashes in such men.

MATERIALS AND METHODS

The study included men in whom substantial hot flashes were associated with androgen deprivation therapy. Hot flash data were collected by daily diary questionnaires during a 1-week baseline period when no therapy was given for hot flashes, as well as for the next 4 weeks when study participants received 12.5 mg. venlafaxine orally twice daily. Questionnaires completed during the 4 weeks ofvenlafaxine therapy also documented data on potential drug toxicity.

RESULTS

Of the 16 evaluable patients who completed the study 10 (63%) had a greater than 50% decrease in hot flash score, as determined using the formula, frequency x severity, by week 4 of treatment versus the baseline week. Median weekly hot flash scores decreased 54% from baseline during week 4 of venlafaxine therapy. Average incidence of severe and very severe hot flashes was reduced from 2.3 daily at baseline to 0.6 daily at study end (p = 0.003). Therapy was generally well tolerated.

CONCLUSIONS

Venlafaxine hydrochloride appears to represent an efficacious new method for alleviating hot flashes in men undergoing androgen ablation therapy. Further evaluation of this compound for alleviating hot flashes is indicated.

Quality of life in hospice patients. A pilot study

The general public and the medical community often perceive dying patients' quality of life (QOL) as rapidly deteriorating before death. However, with appropriate palliative services, this effect may be positively modified. Objective data are lacking on the true experience of dying from the point of view of the patient that this pilot study begins to address. Patients caregivers, and staff in our hospice program completed questionnaires evaluating the patient's QOL every 2 weeks until the patient's death. This pilot study found that patients QOL was relatively high and stable over time. Primary caregivers rated the patient's QOL lower than patient self-ratings, whereas the hospice staff evaluated the patient's QOL similarly to the patient. Many dying patients suffer and are perceived as having no QOL in the final days by their caregivers. This perception may be modified to maintain one's QOL with the help of palliative medical services, thereby relieving the suffering of those who are actively facing death.

Doctor's assistants--do we need them?

OBJECTIVE

To investigate the potential for the doctor's assistant role within an accident and emergency (A&E) department in relation to consultant workload.

METHODS

A time and motion evaluation of the activities of four A&E consultants before and after a doctor's assistant was established as a team member within our department. A review of the literature was undertaken to allow comparisons with the American model of the physician assistant within the emergency department.

RESULTS

The initial evaluation indicated that over 20% of the consultant's time could have been saved if an assistant were available to perform a variety of non-medical tasks. The restudy performed once the assistant was in post indicated less time was spent by the doctors in "medical" clerical duties (6.7% v 11.5% time), telephone use (5.6% v 7.7%), and venepuncture/cannula insertion (0.4% v 2.1%), and more time was spent on consultation over cases (15.3% v 11.3%) and supervision of other staff (9.3% v 4.1%). These five areas changed significantly (p = 0.005 by paired t test).

CONCLUSIONS

The doctor's assistant may have a role in reprofiling the workload of senior doctors in A&E departments in the UK. They may also have a role in reducing the pressure on junior doctors, though this effect was not evaluated.