Predictors of recurrent stroke in African Americans

BACKGROUND

Stroke incidence and mortality are disproportionately higher among African Americans than among whites.

OBJECTIVE

To describe the recurrent stroke characteristics and determine the predictability of known vascular risk factors for stroke recurrence in African Americans.

METHODS

The authors followed 1,809 African Americans in the African-American Antiplatelet Stroke Prevention Study with recent noncardioembolic ischemic stroke for recurrent stroke, recurrent stroke subtype, and disability.

RESULTS

Of the subjects, 10.6% experienced a recurrent stroke during follow-up. The mean interval between eligibility and recurrent stroke was 325 days (median 287 days, SD = 224 days). Stroke recurrence resulted in an average 1.5-point increase in the National Institute of Health Stroke Scale (p < 0.001) and a 3.5-point decrease in modified Barthel Index (p < 0.001). Of previously nondisabled subjects, 48% became disabled or died after stroke recurrence (p < 0.0001). Longitudinal analysis resulted in a hazard for recurrent stroke for each 10-mm Hg increase in systolic blood pressure of 1.103 (95% CI: 1.031 to 1.179, p = 0.004), pulse pressure 1.123 (95% CI: 1.041 to 1.213, p = 0.003), and mean arterial pressure 1.123 (95% CI: 1.001 to 1.260, p = 0.048). Multivariate analysis revealed increases in the recurrent stroke hazard for increases in baseline Glasgow Outcome Score (1.449, 95% CI: 1.071 to 1.961, p = 0.016) and increases in longitudinal pulse pressure (1.009, 95% CI: 1.001 to 1.017, p = 0.029).

CONCLUSION

Recurrent stroke leads to disability and disability predicts recurrent stroke. Hypertension is the most predictive modifiable stroke risk factor.

Location and removal of non-palpable Implanon® implants with the aid of ultrasound guidance

BACKGROUND

Implanon insertion appears to be an easy procedure, but in a small minority of cases difficulties have been encountered with removal if the rod is impalpable.

METHODS

Patients were referred to the contraceptive and sexual health service with non-palpable Implanon. Following a clinical assessment and examination of the arm where the implant had been inserted, an ultrasound examination was carried out to identify and locate the implant. These implants were subsequently removed, some under general anaesthesia and others under local anaesthesia.

RESULTS

Twenty-seven patients were referred to the unit with impalpable Implanon rods. In four cases the rods were palpable and were removed in the clinic setting without the need for further intervention. Positive identification of the implants was achieved in 21 of the remaining 23 cases using ultrasound. No implant was detected in two cases and etonogestrel was not demonstrated serologically in either woman, suggesting non-insertion. All 21 Implanon rods identified by ultrasound were successfully removed. In just over 52% of women a previous attempt at removal had been undertaken prior to referral.

CONCLUSIONS

It is possible to identify and locate impalpable Implanon rods with the aid of ultrasound, facilitating their subsequent safe removal. Although previous reports have identified the position of 'lost' implants using ultrasound, this is the first case series to discuss measuring the skin/implant depth. This parameter, together with the precise position of the implant (in muscle or fat), aids removal. All health professionals inserting and removing contraceptive implants should have been appropriately trained.

The development of an outpatient chemotherapy medication safety program

16005

Background: Through Institute of Medicine publications (To Err is Human) and through the public experience of a major cancer center, chemotherapy safety has been of concern. US Oncology, Inc. (USON) is the nations largest oncology management company, associated with over 900 medical, radiation, gynecologic and pediatric oncologists. In 2004 USON undertook a quality initiative with a principal objective a system-wide approach to medication safety. Methods: Medication safety was identified as a principal concern by a combined clinical/management committee. A questionnaire was prepared for each practice site to differentiate high performing practices in regards to variances from lower performing practices. 8 high performing practices and 8 lower performing practices were physically evaluated by team members. Neither the questionnaire nor onsite evaluation reliably differentiated quality processes. Three issues became apparent: no uniform reporting mechanism, multiple “double-check” interpretations and variable inclusion of medication safety into practice operations. The safety team undertook these first two issues. An online reporting tool was developed. “Double-check” was defined and processes mapped. Results: The team chose 1st hour of chemotherapy as the denominator for medication occurrence reporting. An online reporting tool was developed with now 1 year of experience. 83% of practice sites are reporting, accounting for 445,148 1st hours of chemotherapy. The occurrence rate is 0.66%. Of the total 0.13% is adverse drug reaction, 0.10% is near miss, 0.08% is miscalculation of dose, 0.05% is the wrong dose. Injury to a patient is a very rare event. Conclusions: The development of a culture of quality in an organization with affiliations of national scope is a formidable undertaking. These initial numbers have no comparative measure, as this is self-reporting using a novel denominator. However, there are within the network similar groups for comparison. The challenge continues to be developing a culture of reporting with systematic integration of those reports and quality processes into the fabric of the practice.

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The inter-relationship of hypoxia and phospho-Akt in the pathobiology of malignant pleural mesothelioma

17057

Background: Poor outcomes with conventional oncological treatments for malignant pleural mesothelioma (MPM) have driven the imperative to advance understanding of the disease pathobiology. Carbonic Anhydrase (CA)-IX is a surrogate marker of hypoxia over-expressed in solid tumours. Protein Kinase B, or Akt, known to have important intracellular roles including resistance to apoptosis, is activated in human malignancies and upregulated in hypoxic conditions. This study examined the expression of CA-IX and phosphorylated Akt (pAkt) in tumour samples from patients with MPM, correlating expression with established prognostic factors. The role of pAkt in the survival of an MPM cell line exposed to hypoxic conditions was also examined. Methods: Full local regional ethics committee approval was obtained for this work. Tumour samples from 200 patients with MPM were stained using pAkt and CA-IX specific antibodies. The effect of hypoxia on Akt and pAkt was evaluated in the JU77 mesothelioma cell line in the presence or absence of the phosphatidylinositol-3-kinase inhibitor, LY294002. Results: There was a positive association between the level of CA-IX and pAkt staining, implying that intra-tumoural hypoxia may be a stimulus for Akt phosphorylation. On multivariate analysis increased expression of nuclear pAkt was found to be associated with a poor survival. In-vitro cell culture work showed that, although pAkt is expressed in normoxic conditions in the JU77 cell line, the rates of apoptosis were significantly increased in hypoxic conditions when the phosphorylation of Akt was blocked by LY294002. Conclusions: This work provides evidence for the anti-apoptotic role of pAkt in hypoxic conditions in solid human malignancies. Phospho-Akt may represent a novel therapeutic target in MPM.

No significant financial relationships to disclose.

A hypermutation phenotype and somatic MSH6 mutations in recurrent human malignant gliomas after alkylator chemotherapy

Malignant gliomas have a very poor prognosis. The current standard of care for these cancers consists of extended adjuvant treatment with the alkylating agent temozolomide after surgical resection and radiotherapy. Although a statistically significant increase in survival has been reported with this regimen, nearly all gliomas recur and become insensitive to further treatment with this class of agents. We sequenced 500 kb of genomic DNA corresponding to the kinase domains of 518 protein kinases in each of nine gliomas. Large numbers of somatic mutations were observed in two gliomas recurrent after alkylating agent treatment. The pattern of mutations in these cases showed strong similarity to that induced by alkylating agents in experimental systems. Further investigation revealed inactivating somatic mutations of the mismatch repair gene MSH6 in each case. We propose that inactivating somatic mutations of MSH6 confer resistance to alkylating agents in gliomas in vivo and concurrently unleash accelerated mutagenesis in resistant clones as a consequence of continued exposure to alkylating agents in the presence of defective mismatch repair. The evidence therefore suggests that when MSH6 is inactivated in gliomas, alkylating agents convert from induction of tumor cell death to promotion of neoplastic progression. These observations highlight the potential of large scale sequencing for revealing and elucidating mutagenic processes operative in individual human cancers.

Parabolic pulse evolution in normally dispersive fiber amplifiers preceding the similariton formation regime

We show analytically and numerically that parabolic pulses and similaritons are not always synonyms and that a self-phase modulation amplification regime can precede the self-similar evolution. The properties of the recompressed pulses after SPM amplification are investigated. We also demonstrate that negatively chirped parabolic pulses can exhibit a spectral recompression during amplification leading to high-power chirp-free parabolic pulses at the amplifier output.

The effect of core asymmetries on the polarization properties of hollow core photonic bandgap fibers

We present the results of numerical simulations of the modal properties of Photonic Band Gap Fibers (PBGFs) in which a structural distortion of the silica ring surrounding the air core is gradually introduced. We demonstrate that surface modes supported within such fibers are very sensitive to structural distortions, and that any asymmetric change in the structure can break their degeneracy resulting in associated changes in the anticrossing behavior of the orthogonally polarized core modes, and the development of polarization dependent transmission properties. Our results provide insight into recent experimental observations of wavelength dependent PDL and birefringence in PBGFs.

A randomized clinical trial of activated charcoal for the routine management of oral drug overdose

BACKGROUND

Activated charcoal (AC) is commonly used for the routine management of oral drug overdose.

AIM

To determine whether the routine use of activated charcoal has an effect on patient outcomes.

DESIGN

Randomized controlled unblinded trial.

METHODS

We recruited all adult patients presenting with an oral overdose at The Canberra Hospital, excluding only transfers, late presenters, those who had ingested drugs not adsorbed by activated charcoal or where administration was contraindicated, and very serious ingestions (at the discretion of the admitting physician). Patients were randomized to either activated charcoal or no decontamination.

RESULTS

The trial recruited 327 patients over 16 months. Of 411 presentations, four refused consent, 27 were protocol violations and 53 were excluded from the trial. Only seven were excluded due to the severity of their ingestion. The most common substances ingested were benzodiazepines, paracetamol and selective serotonin reuptake inhibitor antidepressants. More than 80% of patients presented within 4 h following ingestion. There were no differences between AC and no decontamination in terms of length of stay (AC 6.75 h, IQR 4-14 vs. controls 5.5 h, IQR 3-12; p=0.11) or secondary outcomes including vomiting, mortality and intensive care admission.

DISCUSSION

Routine administration of charcoal following oral overdose did not significantly influence length of stay or other patient outcomes following oral drug overdose. There were few adverse events. This does not exclude a role in patients who present shortly after ingestion of highly lethal drugs.

Management of craniofacial abnormalities

A number of congenital and acquired conditions can affect the skull, face and jaws resulting in a wide range of craniofacial abnormalites that commonly present at birth or in early infancy. This article aims to outline the aetiology, pathogenesis, diagnosis and principles of management of those conditions that commonly present to a craniofacial unit namely the craniosynostoses.

Molecular epidemiology of simian T-cell lymphotropic virus type 1 in wild and captive sooty mangabeys

A study was conducted to evaluate the prevalence and diversity of simian T-cell lymphotropic virus (STLV) isolates within the long-established Tulane National Primate Research Center (TNPRC) colony of sooty mangabeys (SMs; Cercocebus atys). Serological analysis determined that 22 of 39 animals (56%) were positive for STLV type 1 (STLV-1). A second group of thirteen SM bush meat samples from Sierra Leone in Africa was also included and tested only by PCR. Twenty-two of 39 captive animals (56%) and 3 of 13 bush meat samples (23%) were positive for STLV-1, as shown by testing with PCR. Nucleotide sequencing and phylogenetic analysis of viral strains obtained demonstrated that STLV-1 strains from SMs (STLV-1sm strains) from the TNPRC colony and Sierra Leone formed a single cluster together with the previously reported STLV-1sm strain from the Yerkes National Primate Research Center. These data confirm that Africa is the origin for TNPRC STLV-1sm and suggest that Sierra Leone is the origin for the SM colonies in the United States. The TNPRC STLV-1sm strains further divided into two subclusters, suggesting STLV-1sm infection of two original founder SMs at the time of their importation into the United States. STLV-1sm diversity in the TNPRC colony matches the high diversity of SIVsm in the already reported colony. The lack of correlation between the lineage of the simian immunodeficiency virus from SMs (SIVsm) and the STLV-1sm subcluster distribution of the TNPRC strains suggests that intracolony transmissions of both viruses were independent events.

Detection and partial characterization of simian immunodeficiency virus SIVsm strains from bush meat samples from rural Sierra Leone

Human immunodeficiency virus type 2 (HIV-2) originated from simian immunodeficiency viruses (SIVs) that naturally infect sooty mangabeys (SMs; Cercocebus atys). In order to further investigate the relationship between HIV-2 and SIVsm, the SIV specific to the SM, we characterized seven new SIVsm strains from SMs sold in Sierra Leone markets as bush meat. The gag, pol, and env sequences showed that, while the viruses of all seven SMs belonged to the SIVsm-HIV-2 lineage, they were highly divergent viruses, in spite of the fact that most of the samples originated from the same geographical region. They clustered in three lineages, two of which have been previously reported. Two of the new SIVsm strains clustered differently in gag and env phylogenetic trees, suggesting SIVsm recombination that had occurred in the past. In spite of the fact that our study doubles the number of known SIVsm strains from wild SMs, none of the simian strains were close to the groups in which HIV-2 was epidemic (groups A and B).

Nitrate reduction byDesulfovibrio desulfuricans: A periplasmic nitrate reductase system that lacks NapB, but includes a unique tetrahemec-type cytochrome, NapM

Many sulphate reducing bacteria can also reduce nitrite, but relatively few isolates are known to reduce nitrate. Although nitrate reductase genes are absent from Desulfovibrio vulgaris strain Hildenborough, for which the complete genome sequence has been reported, a single subunit periplasmic nitrate reductase, NapA, was purified from Desulfovibrio desulfuricans strain 27774, and the structural gene was cloned and sequenced. Chromosome walking methods have now been used to determine the complete sequence of the nap gene cluster from this organism. The data confirm the absence of a napB homologue, but reveal a novel six-gene organisation, napC-napM-napA-napD-napG-napH. The NapC polypeptide is more similar to the NrfH subgroup of tetraheme cytochromes than to NapC from other bacteria. NapM is predicted to be a tetra-heme c-type cytochrome with similarity to the small tetraheme cytochromes from Shewanella oneidensis. The operon is located close to a gene encoding a lysyl-tRNA synthetase that is also found in D. vulgaris. We suggest that electrons might be transferred to NapA either from menaquinol via NapC, or from other electron donors such as formate or hydrogen via the small tetraheme cytochrome, NapM. We also suggest that, despite the absence of a twin-arginine targeting sequence, NapG might be located in the periplasm where it would provide an alternative direct electron donor to NapA.

Investigation of human contacts: a Mycobacterium bovis outbreak among cattle at a California dairy

BACKGROUND

In May 2002, a Mycobacterium bovis outbreak occurred among cattle at a California dairy. We investigated to determine whether persons were infected after working with the cattle or drinking their raw milk.

METHODS

We identified persons with potential contact with infected cattle, including dairy workers, their family members, and slaughterhouse workers. Persons were given a tuberculin skin test (TST), and their occupational and milk-drinking habits were recorded.

RESULTS

Of 88 potential contacts, 78 (90%) were given a TST; 33 (43%) had positive TST results, of whom 32 were Mexican-born (RR 15.8, 95%CI 2.3-108.8). No persons had active tuberculosis. Eighteen (72%) dairy workers, 11 (27%) family members, and four (33%) slaughterhouse workers had positive TST results. After adjusting for Mexican-birth and age, dairy workers were no more likely to have positive TST results than others (adjusted RR 1.2, 95%CI 0.6-2.1). Forty-one (62%) dairy staff and their family members drank raw milk from the dairy; 21 (51%) had positive TST results and were Mexican-born. All 13 US-born raw milk drinkers had negative TST results.

CONCLUSION

A high prevalence of positive TST results was documented among workers at the affected dairy, although results were not independently associated with contact with infected cattle or milk products. Further assessment of California dairy workers should be considered.

Cyclooxygenase-2 protein levels are independent of epidermal growth factor receptor expression or activation in operable non-small cell lung cancer

Both cyclooxygenase (COX)-2 and epidermal growth factor receptor (EGFR) are thought to play important roles in the pathogenesis of non-small cell lung cancer (NSCLC). A number of in vitro studies have postulated a link between EGFR activation and subsequent COX-2 upregulation. The relationship between these factors has not been established in patients with NSCLC. COX-2 and EGFR expression were studied in 172 NSCLC specimens using standard immunohistochemical techniques. Western blotting was used to determine COX-2 and EGFR levels in five NSCLC cell lines. The effect of treatment with EGF on COX-2 expression in A549 cells was assessed.

RESULTS

Both EGFR and COX-2 are overexpressed in NSCLC. The predominant pattern of COX-2 and EGFR staining was cytoplasmic. Membranous EGFR staining was seen in 23.3% of cases. There was no relationship between COX-2 and EGFR expression and survival or any clinicopathological features. No correlation was seen between EGFR expression and COX-2 expression in the immunohistochemical series or in the cell lines. Treatment with EGF did not upregulate COX-2 levels in A549 cells, either in serum free or serum-supplemented conditions.

CONCLUSIONS

Although COX-2 and EGFR are over-expressed in NSCLC neither was of prognostic significance in this series of cases. There is no correlation between these two factors in either tumour samples or cell lines. Although these factors show no correlation in NSCLC, they remain potential, though independent targets for treatment.