Johns Hopkins University School of Medicine

About: Johns Hopkins University School of Medicine is a healthcare organization based out in Baltimore, Maryland, United States. It is known for research contribution in the topics: Population & Cancer. The organization has 44277 authors who have published 79222 publications receiving 4788882 citations.

Mental rotation of the neuronal population vector.

Abstract: A rhesus monkey was trained to move its arm in a direction that was perpendicular to and counterclockwise from the direction of a target light that changed in position from trial to trial. Solution of this problem was hypothesized to involve the creation and mental rotation of an imagined movement vector from the direction of the light to the direction of the movement. This hypothesis was tested directly by recording the activity of cells in the motor cortex during performance of the task and computing the neuronal population vector in successive time intervals during the reaction time. The population vector rotated gradually counterclockwise from the direction of the light to the direction of the movement at an average rate of 732 degrees per second. These results provide direct, neural evidence for the mental rotation hypothesis and indicate that the neuronal population vector is a useful tool for "reading out" and identifying cognitive operations of neuronal ensembles.

Spinal cord stimulation versus repeated lumbosacral spine surgery for chronic pain: a randomized, controlled trial.

Abstract: OBJECTIVE Persistent or recurrent radicular pain after lumbosacral spine surgery is often associated with nerve root compression and is treated by repeated operation or, as a last resort, by spinal cord stimulation (SCS). We conducted a prospective, randomized, controlled trial to test our hypothesis that SCS is more likely than reoperation to result in a successful outcome by standard measures of pain relief and treatment outcome, including subsequent use of health care resources. METHODS For an average of 3 years postoperatively, disinterested third-party interviewers followed 50 patients selected for reoperation by standard criteria and randomized to SCS or reoperation. If the results of the randomized treatment were unsatisfactory, patients could cross over to the alternative. Success was based on self-reported pain relief and patient satisfaction. Crossover to the alternative procedure was an outcome measure. Use of analgesics, activities of daily living, and work status were self-reported. RESULTS Among 45 patients (90%) available for follow-up, SCS was more successful than reoperation (9 of 19 patients versus 3 of 26 patients, P <0.01). Patients initially randomized to SCS were significantly less likely to cross over than were those randomized to reoperation (5 of 24 patients versus 14 of 26 patients, P=0.02). Patients randomized to reoperation required increased opiate analgesics significantly more often than those randomized to SCS (P <0.025). Other measures of activities of daily living and work status did not differ significantly. CONCLUSION SCS is more effective than reoperation as a treatment for persistent radicular pain after lumbosacral spine surgery, and in the great majority of patients, it obviates the need for reoperation.

Comprehensive Discharge Planning With Postdischarge Support for Older Patients With Congestive Heart Failure: A Meta-analysis

Abstract: ContextComprehensive discharge planning plus postdischarge support may reduce readmission rates for older patients with congestive heart failure (CHF).ObjectiveTo evaluate the effect of comprehensive discharge planning plus postdischarge support on the rate of readmission in patients with CHF, all-cause mortality, length of stay (LOS), quality of life (QOL), and medical costs.Data SourcesWe searched MEDLINE (1966 to October 2003), the Cochrane Clinical Trials Register (all years), Social Science Citation Index (1992 to October 2003), and other databases for studies that described such an intervention and evaluated its effect in patients with CHF. Where possible we also contacted lead investigators and experts in the field.Study SelectionWe selected English-language publications of randomized clinical trials that described interventions to modify hospital discharge for older patients with CHF (mean age ≥55 years), delineated clearly defined inpatient and outpatient components, compared efficacy with usual care, and reported readmission as the primary outcome.Data ExtractionTwo authors independently reviewed each report, assigned quality scores, and extracted data for primary and secondary outcomes in an unblinded standardized manner.Data SynthesisEighteen studies representing data from 8 countries randomized 3304 older inpatients with CHF to comprehensive discharge planning plus postdischarge support or usual care. During a pooled mean observation period of 8 months (range, 3-12 months), fewer intervention patients were readmitted compared with controls (555/1590 vs 741/1714, number needed to treat = 12; relative risk [RR], 0.75; 95% confidence interval [CI], 0.64-0.88). Analysis of studies reporting secondary outcomes found a trend toward lower all-cause mortality for patients assigned to an intervention compared with usual care (RR, 0.87; 95% CI, 0.73-1.03; n = 14 studies), similar initial LOS (mean [SE]: 8.4 [2.5] vs 8.5 [2.2] days, P = .60; n = 10), greater percentage improvement in QOL scores compared with baseline scores (25.7% [95% CI, 11.0%-40.4%] vs 13.5% [95% CI, 5.1%-22.0%]; n = 6, P = .01), and similar or lower charges for medical care per patient per month for the initial hospital stay, administering the intervention, outpatient care, and readmission (−$359 [95% CI, −$763 to $45]; n = 4, P = .10 for non-US trials and −$536 [95% CI, −$956 to −$115]; n = 4, P = .03, for US trials).ConclusionComprehensive discharge planning plus postdischarge support for older patients with CHF significantly reduced readmission rates and may improve health outcomes such as survival and QOL without increasing costs.

Patched acts catalytically to suppress the activity of Smoothened

Abstract: Mutations affecting the transmembrane proteins Patched (Ptc) or Smoothened (Smo) that trigger ligand-independent activity of the Hedgehog (Hh) signalling pathway are associated with human tumours such as basal cell carcinoma (BCC) and medulloblastoma. Despite extensive genetic studies demonstrating the importance of these receptor components in embryonic patterning and cancer, the mechanism by which Ptc regulates Smo is not understood. Here we report that Ptc and Smo are not significantly associated within Hh-responsive cells. Furthermore, we show that free Ptc (unbound by Hh) acts sub-stoichiometrically to suppress Smo activity and thus is critical in specifying the level of pathway activity. Patched is a twelve-transmembrane protein with homology to bacterial proton-driven transmembrane molecular transporters; we demonstrate that the function of Ptc is impaired by alterations of residues that are conserved in and required for function of these bacterial transporters. These results suggest that the Ptc tumour suppressor functions normally as a transmembrane molecular transporter, which acts indirectly to inhibit Smo activity, possibly through changes in distribution or concentration of a small molecule.