Perceptual simulations can be as expressive as first-order logic.

Theories asserting that human reasoning is based on perceptual simulations often suppose these simulations are of concrete individual objects and the specific relations that hold among them. However, much human knowledge involves assertions about which relations do not hold, generalities over large numbers of objects and conditional facts. Can simulation theories explain how the mind represents these forms of knowledge, or are they inferior in their expressive power to knowledge representation schemes based on logical formalisms designed specifically to deal with negative, conditional and quantificational knowledge? In this paper, we show how assertions about mental simulations can in fact straightforwardly express all the concepts that comprise first-order logic, including negation, conditionals and both universal and existential quantification. We also speculate on how to extend this approach to deal with probabilistic and more expressive logics.

HIV positivity, protease inhibitor exposure and subclinical atherosclerosis: a systematic review and meta-analysis of observational studies.

CONTEXT: Patients with HIV may have increased risk of atherosclerotic cardiovascular disease owing to multiple biological mechanisms. OBJECTIVE: To evaluate the evidence for subclinical atherosclerosis among patients with HIV. DESIGN: Systematic review of observational studies. DATA SOURCES: We searched Medline, Cochrane DSR, ACP Journal Club, DARE, CMR, HTA, NHSEED, Embase and the Cochrane Controlled Trials Register for studies published before November 2008. STUDY SELECTION: Eligible studies were cross-sectional, cohort, or case-control studies reporting carotid ultrasound intima-media thickness (CIMT), focal plaque incidence, or coronary artery calcium (CAC), as determined by HIV positivity or protease inhibitor (PI) exposure. DATA EXTRACTION: Two independent reviewers abstracted data using a standardised form. The primary outcome was weighted mean difference (WMD) for CIMT comparing HIV positive versus negative patients. Other outcomes included WMD by PI exposure and the odds ratio (OR) for a focal carotid plaque or CAC. Data from six cross-sectional, seven case-control and 13 cohort studies were included, involving 5456 HIV positive and 3600 HIV negative patients. RESULTS: The weighted mean CIMT was 0.04 mm thicker among patients with HIV than among non-HIV patients (95% CI 0.02 to 0.06; p<0.001). HIV positivity was not associated with carotid plaque or CAC. PI exposure did not significantly affect CIMT, carotid plaque, or CAC. There was evidence of publication bias and stratified analysis and meta-regression showed outcomes were influenced by study design, age, gender and smoking. However, HIV positivity slightly increased CIMT even after sensitivity analyses. CONCLUSIONS: HIV infection and PI exposure are not strong independent risk factors for subclinical atherosclerosis. Confounding may contribute to overestimation of the risk associated with HIV and PI exposure.

Importance of TURP in diagnosing prostate cancer in men with multiple negative biopsies.

OBJECTIVE: Patients with persistently elevated PSA and multiple negative TRUS guided 12-core biopsies, present a clinical conundrum. We evaluated the efficacy of transurethral biopsy and/or resection in abetting prostate cancer diagnosis. PATIENTS AND METHODS: Eleven patients who had prostate cancer diagnosed only on TURP following TRUS guided (24-48 cores) negative biopsies, including five who underwent radical prostatectomy were assessed. Extent and site of tumour was analysed in relation to the TURP cavity. RESULTS: Mean age was 61.8 years (PSA range: 3.8-20.9 ng/ml.). Patients had TURP for worsening LUTS with chippings diagnosing invasive prostate cancer. Organ confined anterior prostate cancer was diagnosed in five who had radical prostatectomy. CONCLUSION: Anteriorly directed transurethral biopsies and/or TURP help in the diagnosis of prostate cancer in patients with multiple negative biopsies. Patients with anterior prostate cancer tend to have organ-confined disease even with higher PSA.

Granulocytic sarcoma of the breast antedating acute myelogenous leukemia.

We report a rare case of granulocytic sarcoma of the breast presenting as an isolated breast lump antedating bone marrow manifestation of acute myelogenous leukaemia.

Development of the Crash Injury Research and Engineering Network.

The Crash Injury Research and Engineering Network has developed a computer database and wide area network for data sharing and analysis among 8 trauma centers. The computer database extends the National Highway Traffic Safety Administration's National Automotive Sampling System with medical- and trauma-related variables in a relational/object database system. The medical data include injury location details, injury subclassification systems, and medical images for better biomechanical injury evaluation. Key data elements are migrated to a core repository so that all centers can review the status of case acquisition across the network. Cases, whole or in part, may be migrated between centers so that individual center expertise may be shared in evaluating the cause of injury. Electronic rounds, where cases are reviewed simultaneously across multiple centers, are possible.

Emphysematous cystitis.

A case of emphysematous cystitis in a diabetic female is described. Its presentation is non-specific and the prognosis depends on then degree of aggressiveness at presentation. Early diagnosis and aggressive medical and surgical management of gas-forming organisms are vital.

Lack of role of TGF-beta 1 in decreased lymphoproliferative response in HIV-1 infection.

We investigated whether reduction of the phytohemagglutinin (PHA)-induced proliferative response of lymphocytes from HIV type-1 (HIV-1)-infected (HIV+) individuals could be explained by overproduction of transforming growth factor-beta 1 (TGF-beta 1), a strong inhibitor of T cell proliferation. PHA-stimulated PBMC from 40 HIV- and 42 HIV+ homosexual men from the Baltimore Center of the Multicenter AIDS Cohort Study (MACS) were studied using Northern blot analysis of expression of TGF-beta 1 mRNA and determining the effects of anti-TGF-beta 1 neutralizing antibody on PHA-induced proliferative responses. Compared to the HIV- donors, HIV+ donors did not show increased expression of TGF-beta 1 mRNA in unstimulated or PHA-stimulated PBMC. Furthermore, a neutralizing antibody to TGF-beta 1 did not reverse the decreased proliferative response of PBMC from HIV+ individuals to PHA or interleukin-2. These results indicate that TGF-beta 1 is not involved in T cell proliferation defects seen in HIV+ donors.

Relationship between IL-2 receptor expression and proliferative responses in lymphocytes from HIV-1 seropositive homosexual men.

Previous studies have shown that exogenous IL-2 does not correct the reduction in phytohaemagglutinin (PHA)-induced proliferation of lymphocytes from HIV-1 infected (HIV+) individuals. We investigated the mechanism of this reduction to determine if reduced expression of the complete IL-2 receptor (IL-2R) was responsible. In a series of experiments, PHA-stimulated lymphocytes from a total of 89 HIV- and 93 HIV+ homosexual men from the Baltimore Multicentre AIDS Cohort Study (MACS) were studied to determine the expression of messages for the alpha and beta subunits of the IL-2R, the binding of 125I-IL-2 to high affinity IL-2R, and the effect of IL-2 on cell proliferation. Compared to HIV- donors, PHA-stimulated lymphocytes from most HIV+ donors demonstrated (i) a reduction in high affinity IL-2R expression that correlated with the reduction in the IL-2-induced proliferative response; and (ii) a reduction in expression of both IL-2R alpha- and beta-chain mRNA which may be responsible for decreased high affinity IL-2R expression. However, lymphocytes from some HIV+ individuals had borderline low IL-2-induced proliferation despite normal or elevated expression of high affinity IL-2R. These results suggest that decreased expression of IL-2R may account, at least in part, for the lower proliferative response of cells from HIV+ donors.

Mucinous cystadenocarcinoma of the pancreas: diagnosis by fine-needle aspiration cytology.

Two cases of mucinous cystadenocarcinoma of the pancreas are described in which the diagnosis was made from the material obtained by a computed tomography-guided fine-needle aspiration cytology examination. It is strongly felt that aspiration cytology, when performed under imaging guidance, is sensitive and specific in the diagnosis of mucinous cystadenocarcinoma and allows for a relatively simple yet confident diagnostic interpretation of this uncommon pancreatic tumour.

Renal cell carcinoma--an unusual presentation and sequel.

A 30 year old woman presented with an abscess in the renal fossa 4 years after nephrectomy for an incidentally discovered renal cell carcinoma.

Low dose low osmolar intravenous urography.

A prospective double blind randomised trial using 25 ml of Hexabrix 320 (ioxaglate, May and Baker), Niopam 370 (iopamidol, Merck) or Omnipaque 350 (iohexol, Nycomed) intravenous urography was carried out. The results showed no perceptible difference in the diagnostic quality of urograms with each of the media. An additional 25 ml of contrast medium was required by 4% of patients in order to obtain a satisfactory examination. We recommend that a dose of 25 ml of low-osmolar medium be used for all patients with the exception of the obese, those taking diuretics or those who have renal impairment.

An evaluation of the post-micturition radiograph following intravenous urography.

A prospective study of the post-micturition radiograph in 539 consecutive intravenous urograms was performed. In only 1% of patients was a post-micturition residue demonstrated only on this radiograph and not on the control radiograph. The post-micturition radiograph helped in making a firm diagnosis in two out of six patients with vesico-ureteric junction calculi, which were suspected but could not be confidently diagnosed without it. It was also helpful in two out of 13 bladder patients with carcinoma, enabling a confident diagnosis to be established where the lesion had only been suspected. It would seem pertinent to restrict the post-micturition radiograph to cases of haematuria and possible vesico-ureteric calculi.

Bladder neurofibromas causing ureteric obstruction in Von Recklinghausen's disease.

A case of bladder involvement by Von Recklinghausen's disease with consequent hydronephrosis and hydroureters is presented. The intravenous urographic and ultrasonic appearances are correlated.

[Lymphocyte sensitivity to brain specific glycoprotein in multiple sclerosis]. / Lymphocyten-Sensibilisierung gegen hirnspezifisches Glykoprotein bei Multipler Sklerose

The lymphocytes of seven out of eight multiple sclerosis patients were sensitized to brain-specific glycoproteins that had been isolated from extracts of human white matter and purified by means of affinity chromatography utilizing specific antibodies as immunoadsorbents. The diagnosis of multiple sclerosis for the eighth patient, whose lymphocytes were not sensitized, was doubtful. A significant correlation between the severity of the disease and degree of lymphocyte sensitization was not obtained, although the most disabled patient showed the greatest sensitization.