Phosphorylation of pRb: mechanism for RB pathway inactivation in MYCN-amplified retinoblastoma.

A small, but unique subgroup of retinoblastoma has been identified with no detectable mutation in the retinoblastoma gene (RB1) and with high levels of MYCN gene amplification. This manuscript investigated alternate pathways of inactivating pRb, the encoded protein in these tumors. We analyzed the mutation status of the RB1 gene and MYCN copy number in a series of 245 unilateral retinoblastomas, and the phosphorylation status of pRb in a subset of five tumors using immunohistochemistry. There were 203 tumors with two mutations in RB1 (RB1-/- , 83%), 29 with one (RB1+/- , 12%) and 13 with no detectable mutations (RB1+/+ , 5%). Eighteen tumors carried MYCN amplification between 29 and 110 copies: 12 had two (RB1-/- ) or one RB1 (RB1+/- ) mutations, while six had no mutations (RB1+/+ ). Immunohistochemical staining of tumor sections with antibodies against pRb and phosphorylated Rb (ppRb) displayed high levels of pRb and ppRb in both RB1+/+ and RB1+/- tumors with MYCN amplification compared to no expression of these proteins in a classic RB1-/- , MYCN-low tumor. These results establish that high MYCN amplification can be present in retinoblastoma with or without coding sequence mutations in the RB1 gene. The functional state of pRb is inferred to be inactive due to phosphorylation of pRb in the MYCN-amplified retinoblastoma without coding sequence mutations. This makes inactivation of RB1 by gene mutation or its protein product, pRb, by protein phosphorylation, a necessary condition for initiating retinoblastoma tumorigenesis, independent of MYCN amplification.

Compliance with pharmacotherapy and direct healthcare costs in patients with Parkinson's disease: a retrospective claims database analysis.

BACKGROUND: Parkinson's disease (PD) is a progressive neurological disorder for which, at present, there is no cure. Current therapy is largely based on the use of dopamine agonists and dopamine replacement therapy, designed to control the signs and symptoms of the disease. The majority of current treatments are administered in tablet form and can involve multiple daily doses, which may contribute to sub-optimal compliance. Previous studies with small groups of patients suggest that non-compliance with treatment can result in poor response to therapy and may ultimately increase direct and indirect healthcare costs. OBJECTIVE: To determine the extent of non-compliance within the general PD population in the USA as well as the patient characteristics and healthcare costs associated with compliance and non-compliance. METHODS: A retrospective analysis from a managed care perspective was conducted using data from the USA PharMetrics patient-centric claims database. PharMetrics claims data were complete from 31 December 2005 to 31 December 2009. Patients were included if they had at least two diagnoses for PD between 31 December 2005 and 31 December 2008, were older than 18 years of age, were continuously enrolled for at least 12 months after the date of the most recent PD diagnosis, and had no missing or invalid data. The follow-up period was the most recent 12-month block of continuous enrollment that occurred between 2006 and 2009. Patients were required to have at least one PD-related prescription within the follow-up period. The medication possession ratio (MPR) was used to categorise patients as compliant or non-compliant. Direct all-cause annual healthcare costs for patients with PD were estimated for each patient, and regression analyses were conducted to determine predictors for non-compliance. RESULTS: A total of 15,846 patients were included, of whom 46 % were considered to be non-compliant with their prescribed medication (MPR <0.8). Predictors of non-compliance included prescription of a medication administered in multiple daily doses (p < 0.0001), a period of <2 years since the initial PD diagnosis (p = 0.0002), a diagnosis of gastrointestinal disorder (p < 0.0001), and a diagnosis of depression (p < 0.0001). Non-compliance was also found to be related to age, with a lower odds of non-compliance in patients aged 41-80 years than in patients aged ≥81 years (p < 0.05). Although total drug mean costs were higher for compliant patients than non-compliant patients (driven mainly by the cost of PD-related medications), the mean costs associated with emergency room and inpatient visits were higher for patients non-compliant with their prescribed medication. Overall, the total all-cause annual healthcare mean cost was lower for compliant ($77,499) than for non-compliant patients ($84,949; p < 0.0001). CONCLUSION: Non-compliance is prevalent within the general USA PD population and is associated with a recent PD diagnosis, certain comorbidities, and multiple daily treatment dosing. Non-compliance may increase the burden on the healthcare system because of greater resource usage compared with the compliant population. Treatments that require fewer daily doses may have the potential to improve compliance, which in turn could reduce the economic burden associated with PD.

Differential calcium dependence of axonal versus somatodendritic dopamine release, with characteristics of both in the ventral tegmental area.

Midbrain dopamine (DA) neurons in the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) exhibit somatodendritic release of DA. Previous studies indicate a difference between the Ca(2+) dependence of somatodendritic DA release in the SNc and that of axonal DA release in dorsal striatum. Here, we evaluated the Ca(2+) dependence of DA release in the VTA and nucleus accumbens (NAc) shell for comparison with that in the SNc and dorsal striatum. Release of DA was elicited by single-pulse stimulation in guinea-pig brain slices and monitored with subsecond resolution using carbon-fiber microelectrodes and fast-scan cyclic voltammetry. In dorsal striatum and NAc, DA release was not detectable at extracellular Ca(2+) concentrations ([Ca(2+)](o)) below 1 mM; however, a progressive increase in evoked extracellular DA concentration ([DA](o)) was seen with [Ca(2+)](o) ≥ 1.5 mM. By contrast, in SNc and VTA, robust increases in [DA](o) could be elicited in 0.25 mM [Ca(2+)](o) that were ∼60% of those seen in 1.5 mM [Ca(2+)](o). In SNc, a plateau in single-pulse evoked [DA](o) was seen at [Ca(2+)](o) ≥ 1.5 mM, mirroring the release plateau reported previously for pulse-train stimulation in SNc. In VTA, however, evoked [DA](o) increased progressively throughout the range of [Ca(2+)](o) tested (up to 3.0 mM). These functional data are consistent with the microanatomy of the VTA, which includes DA axon collaterals as well as DA somata and dendrites. Differences between axonal and somatodendritic release data were quantified using Hill analysis, which showed that the Ca(2+) dependence of axonal DA release is low affinity with high Ca(2+) cooperativity, whereas somatodendritic release is high affinity with low cooperativity. Moreover, this analysis revealed the dual nature of DA release in the VTA, with both somatodendritic and axonal contributions.

Bacteriology of blood, wound, and sputum cultures from non-US casualties treated in a combat support hospital in Iraq.

A review of culture results from non-US casualties in Iraq revealed gram-negative bacteria were the most commonly isolated pathogens. Cultures of respiratory fluid yielded positive results earlier than cultures of wound or blood samples and potentially serve as an earlier marker of future infections. Continued aggressive infection control for non-US casualties is needed.

Community meetings for emergency research community consultation.

OBJECTIVE: To survey attendees at community meetings for an emergency research protocol and determine whether these meetings aid participants' understanding and decision to support the proposed emergency research. DESIGN: Postmeeting questionnaire. SETTING: Three community meetings for the PolyHeme study in San Antonio area. SUBJECTS: One hundred fifty community meeting attendees. INTERVENTIONS: PolyHeme research team representatives made a study presentation concerning exception to informed consent regulations. In addition, institutional review board (IRB) members attended these meetings and made a separate presentation about the IRB approval of research and the exception to informed consent in emergency research. The IRB members requested attendees to voluntarily complete an additional Community Consultation Survey assessing demographics, community meeting satisfaction, and impact of the community meeting on their attitudes toward emergency research studies. MEASUREMENTS AND MAIN RESULTS: Feedback to the PolyHeme investigators with their validation questions indicated that 35% of the respondents objected to research without prior consent, but 82% gave approval for the study in the local community; 137 attendees completed the additional Community Consultation Survey. The average score on the adequacy of information provided about the PolyHeme study was 0.58 on a 5-point Likert scale (-2 to +2). Adequacy of IRB background information on human subjects research received an average score of 0.56, and the overall clarity of the information on community consultation was 0.91. Although 80% of respondents felt there was a potential benefit from PolyHeme, <67% would either want to participate or enroll their family members with or without prior consent. CONCLUSIONS: The majority of community meeting attendees understand basic concepts and regulations of emergency research without prior consent. Despite an 82% concurrence with the study in their community, approximately 30% of persons would not willingly choose to participate in emergency research or provide consent for their family members despite knowledge about the process.

Acinetobacter pneumonia: a review.

Acinetobacter species are becoming a major cause of nosocomial infections, including hospital-acquired and ventilator-associated pneumonia. Acinetobacter species have become increasingly resistant to antibiotics over the past several years and currently present a significant challenge in treating these infections. Physicians now rely on older agents, such as polymyxins (colistin), for treatment. This paper reviews the epidemiology, treatment, and prevention of this emerging pathogen.

Atypical Q fever in US soldiers.

Q fever is an emerging infectious disease among US soldiers serving in Iraq. Three patients have had atypical manifestations, including 2 patients with acute cholecystitis and 1 patient with acute respiratory distress syndrome. Providers must be aware of Q fever's signs and symptoms to avoid delays in treatment.

Ehrlichiosis: making the diagnosis in the acute setting.

Human monocytic ehrlichiosis (HME) is a tick-borne disease transmitted during the summer months in the mid-Atlantic, southeastern and south-central United States. A large proportion of patients presenting with ehrlichiosis must be hospitalized because of the severity of their presenting signs, symptoms and lab abnormalities. We report a case of HME presenting with negative serologies and positive DNA PCR for Ehrlichia chaffeensis during the acute illness. The patient was empirically treated with doxycycline before the availability of diagnostic test results and had a rapid recovery. This report summarizes the common findings of ehrlichiosis on presentation, diagnostic strategies, and treatment options. This case emphasizes the importance of considering tick-borne diseases in the differential diagnosis for patients presenting with nonspecific febrile syndromes in endemic areas and using the clinical scenario to determine whether empiric treatment for a tick-borne disease is necessary. Delaying treatment while awaiting confirmatory tests is unnecessary, and may result in a less favorable patient outcome.

Ertapenem susceptibility of extended spectrum beta-lactamase-producing organisms.

BACKGROUND: Infections caused by multiply drug resistant organisms such as extended spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae are increasing. Carbapenems (imipenem and meropenem) are the antibiotics commonly used to treat these agents. There is limited clinical data regarding the efficacy of the newest carbapenem, ertapenem, against these organisms. Ertapenem susceptibility of ESBL-producing E. coli and K. pneumoniae clinical isolates were evaluated and compared to imipenem to determine if imipenem susceptibility could be used as a surrogate for ertapenem susceptibility. METHODS: 100 ESBL isolates (n = 34 E. coli and n = 66 K. pneumoniae) collected from 2005-2006 clinical specimens at WRAMC were identified and tested for susceptibility by Vitek Legacy [bioMerieux, Durham, NC]. Ertapenem susceptibility was performed via epsilometer test (E-test) [AB Biodisk, Solna, Sweden]. RESULTS: 100% of ESBL isolates tested were susceptible to ertapenem. 100% of the same isolates were also susceptible to imipenem. CONCLUSION: These results, based on 100% susceptibility, suggest that ertapenem may be an alternative to other carbapenems for the treatment of infections caused by ESBL-producing E. coli and K. pneumoniae. Clinical outcomes studies are needed to determine if ertapenem is effective for the treatment of infection caused by these organisms. However, due to lack of resistant isolates, we are unable to conclude whether imipenem susceptibility accurately predicts ertapenem susceptibility.

In harm's way: infections in deployed American military forces.

Hundreds of thousands of American service members have been deployed to Afghanistan and Iraq since 2001. With emphasis on the common infections and the chronic infections that may present or persist on their return to the United States, we review the data on deployment-associated infections. These infections include gastroenteritis; respiratory infection; war wound infection with antibiotic-resistant, gram-negative bacteria; Q fever; brucellosis; and parasitic infections, such as malaria and leishmaniasis.

Limited regulation of somatodendritic dopamine release by voltage-sensitive Ca channels contrasted with strong regulation of axonal dopamine release.

The mechanism underlying somatodendritic release of dopamine (DA) appears to differ from that of axon-terminal release. Specifically, somatodendritic DA release in the substantia nigra pars compacta (SNc) persists in low extracellular Ca2+ concentrations that are insufficient to support axonal release in striatum, suggesting that limited Ca2+ entry is necessary to trigger somatodendritic release. Here, we compared the role of voltage-dependent Ca2+ channels in mediating DA release in striatum versus SNc using specific blockers of N-, P/Q-, T-, R- and L-type Ca2+ channels individually and in combination. Release of DA evoked by a single stimulus pulse in the dorsal striatum and SNc of guinea-pig brain slices was monitored in real time using carbon-fiber microelectrodes with fast-scan cyclic voltammetry. Single-pulse evoked DA release was shown to be independent of regulation by concurrently released glutamate or GABA acting at ionotropic receptors in both regions. Under these conditions, striatal DA release was completely prevented by an N-type channel blocker, omega-conotoxin GVIA (100 nm), and was decreased by 75% by the P/Q-type channel blocker omega-agatoxin IVA (200 nm). Blockade of T-type channels with Ni2+ (100 microm) or R-type channels with SNX-482 (100 nm) decreased axonal release in striatum by 25%, whereas inhibition of L-type channels with nifedipine (20 microm) had no effect. By contrast, none of these Ca2+-channel blockers altered the amplitude of somatodendritic DA release in the SNc. Even a cocktail of all blockers tested did not alter release-signal amplitude in the SNc, although the duration of the release response was curtailed. The limited involvement of voltage-dependent Ca2+ channels in somatodendritic DA release provides further evidence that minimal Ca2+ entry is required to trigger the release process, compared with that required for axon-terminal release.

The remote diagnosis of malaria using telemedicine or e-mailed images.

We determined the ability of blinded remote expert microscopy to identify malaria parasites through transmission of malaria smear images via telemedicine and as e-mail attachments. Protocols for malaria smear transmission included: (1) transmission of sender-selected televised smears at various bandwidths (Bw), (2) transmission of remote reader-directed televised smears at various Bw, and (3) transmission of digital photomicrographs as e-mail attachments. Twenty (14%) of 147 sender-selected, and 13 (6%) of 221 reader-directed, images were deemed unreadable by slide readers. The presence or absence of malaria was correctly identified in 98% of the remaining images. Sixty-four (34%) of 190 digital microphotographs were deemed unreadable, while the presence or absence of malaria was correctly identified in 100% of the remaining images. Correct speciation ranged from 45% to 83% across various transmission methods and Bw. The use of telemedicine and e-mail technology shows promise for the remote diagnosis of malaria.

Infectious diseases during wartime.

PURPOSE OF REVIEW: The infectious disease challenges of war include pathogens endemic to the geographic area of operations as well as wound infections with common environmental microorganisms. This review summarizes papers, unpublished data and personal communications from 2004-2005 pertaining to infectious diseases during war with a focus on the current operations in Iraq and Afghanistan. RECENT FINDINGS: To date, there have been several hundred cases of cutaneous leishmaniasis and five cases of visceral leishmaniasis among US military personnel serving in southwest Asia. There have been reports of malaria in soldiers serving in Afghanistan and an outbreak of acute eosinophilic pneumonia among soldiers serving in or near Iraq. Diarrheal illness is a well-known threat to military operations and remains problematic for combatants throughout the theater of operations. Infectious complications caused by multiply drug-resistant Acinetobacter baumannii have been particularly challenging for healthcare providers managing the wounded evacuated from Iraq. We are now facing outbreaks of nosocomial infection with this pathogen in military treatment facilities in Europe and the USA. SUMMARY: Historically, infectious diseases have had significant impact on the conduct of military operations, and the conflict in southwest Asia is no exception. Physicians caring for returning military personnel should be aware of the diseases prevalent in this campaign, particularly cutaneous leishmaniasis and infections with multiply drug-resistant A. baumannii.

Multidrug-resistant Acinetobacter extremity infections in soldiers.

War wound infection and osteomyelitis caused by multidrug-resistant (MDR) Acinetobacter species have been prevalent during the 2003-2005 military operations in Iraq. Twenty-three soldiers wounded in Iraq and subsequently admitted to our facility from March 2003 to May 2004 had wound cultures positive for Acinetobacter calcoaceticus-baumannii complex. Eighteen had osteomyelitis, 2 burn infection, and 3 deep wound infection. Primary therapy for these infections was directed antimicrobial agents for an average of 6 weeks. All soldiers initially improved, regardless of the specific type of therapy. Patients were followed up to 23 months after completing therapy, and none had recurrent infection with Acinetobacter species. Despite the drug resistance that infecting organisms demonstrated in this series, a regimen of carefully selected extended antimicrobial-drug therapy appears effective for osteomyelitis caused by MDR Acinetobacter spp.

Vesicular reuptake inhibition by a synaptotagmin I C2B domain antibody at the squid giant synapse.

Synaptotagmin (Syt) I, a ubiquitous synaptic vesicle protein, comprises a transmembrane region and two C2 domains. The C2 domains, which have been shown to be essential for both synaptic vesicle exocytosis and endocytosis, are also seen as the Ca(2+) sensors in synaptic vesicular release. In a previous study, we reported that a polyclonal antibody raised against the squid (Loligo pealei) Syt I C2B domain, while inhibiting vesicular endocytosis, was synaptic release neutral at the squid giant synapse. Recent reports concerning the C2B requirements for synaptic release prompted us to readdress the role of C2B in squid giant synapse function. Presynaptic injection of another anti-Syt I-C2B antibody (using recombinant whole C2B domain expressed in mammalian cell culture as an antigen) into the presynaptic terminal reproduced our previous results, i.e., reduction of vesicular endocytosis without affecting synaptic release. This set of results addresses the issue of the geometrical arrangement of the Ca(2+) sensor, allowing the C2B domain antibody to restrict Ca(2+)-dependent C2B self-oligomerization without modifying the Ca(2+)-dependent release process.

Devices for rapid diagnosis of Malaria: evaluation of prototype assays that detect Plasmodium falciparum histidine-rich protein 2 and a Plasmodium vivax-specific antigen.

The ParaSight F test was developed as a pioneer industry effort in the large-scale, process-controlled production of a device for the rapid diagnosis of malaria. This device performed well in field settings but was limited to the detection of a single malaria species, Plasmodium falciparum. The ParaSight F+V assay advanced upon the ParaSight F test format by incorporating a monoclonal antibody directed against a proprietary Plasmodium vivax-specific antigen, in addition to the antibody directed against P. falciparum histidine-rich protein 2, which was used in the ParaSight F assay. The modified assay was developed to add the capability to detect P. falciparum and P. vivax in a single-test-strip format. The present study evaluated three distinct ParaSight F+V prototypes with samples from symptomatic patients in regions of Thailand and Peru where malaria is endemic. Over a 2-year enrollment period (1998 and 1999), a total of 4,894 patients consented to participation in the study. Compared with the results for duplicate microscopic examinations of Giemsa-stained blood smears as the reference diagnostic standard, each successive prototype showed substantial improvement in performance. The final ParaSight F+V prototype, evaluated in 1999, had an overall sensitivity for detection of asexual P. falciparum parasites of 98%. The sensitivity of the device was 100% for P. falciparum densities of >500 parasites/ micro l, with a sensitivity of 83% for parasite densities of 5,000/ micro l, 92% for parasite densities of 1,001 to 5,000/ micro l, 94% for parasite densities of 501 to 1,000/ micro l, and 55% for parasite densities of 1 to 500/ micro l. The specificity for the exclusion of P. vivax was 87%. The areas under the receiver operating characteristic curves for the diagnostic performance of the assay for the detection of P. falciparum and P. vivax were 0.8907 and 0.8522, respectively. These findings indicate that assays for rapid diagnosis have the potential to enhance diagnostic capabilities in those instances in which skilled microscopy is not readily available.