Specific amino acids in the N-terminus of the gp41 ectodomain contribute to the stabilization of a soluble, cleaved gp140 envelope glycoprotein from human immunodeficiency virus type 1

The HIV-1 envelope glycoprotein is expressed on the viral membrane as a trimeric complex, formed by three gp120 surface glycoproteins non-covalently associated with three membrane-anchored gp41 subunits. The labile nature of the association between gp120 and gp41 hinders the expression of soluble, fully cleaved, trimeric gp140 proteins for structural and immunization studies. Disruption of the primary cleavage site within gp160 allows the production of stable gp140 trimers, but cleavage-defective trimers are antigenically dissimilar from their cleaved counterparts. Soluble, stabilized, proteolytically cleaved, trimeric gp140 proteins can be generated by engineering an intermolecular disulfide bond between gp120 and gp41 (SOS), combined with a single residue change, I559P, within gp41 (SOSIP). We have found that SOSIP gp140 proteins based on the subtype A HIV-1 strain KNH1144 form particularly homogenous trimers compared to a prototypic strain (JR-FL, subtype B). We now show that the determinants of this enhanced stability are located in the N-terminal region of KNH11144 gp41 and that, when substituted into heterologous Env sequences (e.g., JR-FL and Ba-L) they have a similarly beneficial effect on trimer stability. The stabilized trimers retain the epitopes for several neutralizing antibodies (b12, 2G12, 2F5 and 4E10) and the CD4-IgG2 molecule, suggesting that the overall antigenic structure of the gp140 protein has not been adversely impaired by the trimer-stabilizing substitutions. The ability to increase the stability of gp140 trimers might be useful for neutralizing antibody-based vaccine strategies based on the use of this type of immunogen.     

Induction of host protective Th1 immune response by chemokines in Leishmania donovani-infected BALB/c mice

The resolution from leishmanial infection is dependent on the coordinated interactions between the components of the cell mediated immune system and the activation of T-cell population into appropriate cytokine production and the activation of macrophages. Earlier reports established that C-C chemokines particularly macrophage inflammatory protein (MIP)-1alpha and macrophage chemoattractant protein (MCP)-1 restrict the parasitic burden via the regulation of impaired protein kinase C (PKC) signalling and induction of free-radical generation in murine leishmaniasis. This study explored the role of MIP-1alpha and MCP-1 in the induction of T helper 1 (Th1) immune response and suppression of T helper 2 (Th2) response in Leishmania donovani-infected BALB/c mice. These chemokines induced the known pro-inflammatory cytokine interleukin (IL)-12 secretion and inhibited the secretion of anti-inflammatory cytokines IL-10 and transforming growth factor-beta in infected macrophages. Impaired antigen presentation capability of infected macrophages was also restored by the chemokine treatment. C-C chemokine treatment resulted in reduced levels of mRNA expression of IL-10, but increased levels of mRNA expression of IL-12p40, interferon (IFN)-gamma, tumour necrosis factor-alpha and inducible nitric oxide synthase in both liver mononuclear cells as well as in splenocytes, reflecting a switch of CD4+ differentiation from Th2 to Th1. Flow cytometric analysis of infected spleen cells suggested that C-C chemokine treatment enhances the CD4+ T cells to produce increased levels of IFN-gamma. These studies hypothesize a promising immuno-prophylactic effect of chemokines against leishmaniasis by induction of Th1 cytokine release imparting a long-term resistance.     

Atypical presentations of melioidosis as emerging threat: a case report

We report two atypical presentations of melioidosis as mediastinal lymphadenitis and prostatic abscess with Burkholderia pseudomallei, the emerging category 2 organism which led to diagnostic and therapeutic dilemma and thereby, delay in appropriate management. Any similar presentation should always be supported by microbiological opinion without any delay, which can help in instituting proper antibiotics with successful outcome.     

Implementing and validating a care protocol for older adults with cancer in resource limited settings with a newly developed screening tool

BackgroundCancer in the aging population presents manifold challenges. In the resource-limited settings of developing countries, concrete steps to optimize care for older adults with cancer are required.Materials and methodThis prospective, observational study was divided in two parts. In the first part, older adults (≥60 years) with a tissue diagnosis of cancer underwent a preliminary, detailed assessment of relevant geriatric domains. The patients were followed up at 4, 12 and 24 weeks, and their survival status was recorded. In the second part a newly developed screening tool, “SCreening of the Older PErson with Cancer”, Version1 (SCOPE-C) was validated on patients with similar characteristics.Results419 participants were enrolled in the study. The mean age of the participants was 66.6 ± 6.2 years, 75% had functional impairment, 35% had malnutrition, and 64% had more than one co-morbidity. The median survival time was 22 weeks from the index visit. Male gender, functional decline, cognitive impairment, malnutrition, and treatment modality were found to be independently associated with survival. Individual Scores on the SCOPE-C Version1 scale were correlated with survival status at 24 weeks, and a cutoff score of 64 had a 72.2% sensitivity and 77.3% specificity for better prognosis.ConclusionThe present study is a comprehensive attempt to assess older adults with cancer with limited resources in a busy health system. A preliminary assessment with a prognostic screening tool may streamline care in resource-limited settings and aid clinicians in making treatment decisions.     

Central neuropathic itch from spinal-cord cavernous hemangioma: a human case, a possible animal model, and hypotheses about pathogenesis

Cavernous hemangiomas (cavernomas) of the spinal cord are rare congenital malformations that comprise less than 5% of all intramedullary lesions. Despite this rarity, we describe the third case of central neuropathic itch associated with intramedullary cavernoma. Since fewer than 10 cases of central spinal itch from all causes have been published, this concurrence suggests the possibility of a specific association. A middle-aged man developed chronic disabling neuropathic itch and pain affecting his left shoulder and arm after frank hemorrhage of a midcervical cavernoma. We hypothesize that the relatively rostro-dorsal location of his lesion increased its likelihood of causing itch as well as pain. The microscopic pathology of cavernomas, specifically their gliotic rim containing hemosiderin-laden phagocytes, fosters ectopic firing of nearby neurons and makes cranial cavernomas highly epileptogenic. We hypothesize that these pathological features predispose cavernomas to cause central itch if they are located near, but spare, the central itch projection neurons in lamina I of the dorsal horn. Quisqualate injections into the deeper layers (neck) of the dorsal horns of rats produce pathologically similar lesions. Such rats develop unilateral dermatomal hyperalgesia and self-injurious scratching and biting (autotomy). Although this pathological grooming is currently interpreted as a response to chronic pain, we propose that it more likely models scratching provoked by central neuropathic itch, as seen in our patient and others. Study of quisqualate-injected rats may provide leads towards new treatments for neuropathic itch.     

Emergency physicians can reliably assess emergency department patient cardiac output using the USCOM continuous wave Doppler cardiac output monitor

Objectives: 1 To develop a training package for ultrasonic cardiac output monitor (USCOM) cardiac output assessments and determine the number of proctored studies necessary for skill acquisition. 2 To develop criteria for acceptance of cardiac output results obtained with the USCOM. 3 To evaluate the reliability of USCOM cardiac output assessments in the ED. Methods: The authors developed an audiovisual training package. Four emergency physicians and one geriatrician subsequently underwent hands‐on training, and skill acquisition was assessed at the fifth, 10th, 15th and 20th examinations. Six image‐scoring criteria were developed to assess acoustic image quality. Upon completion of training a protocol was developed to optimize interassessor reliability. Two trained emergency physicians then performed blinded examinations on ED patients using the protocol and interassessor reliability was evaluated. Results: During training average image score improved between the fifth and 20th assessed patient from 4.6 (95% CI 4.0–5.3) to 5.5 (95% CI 5.0–6.0, P_t‐test = 0.02) out of 6 and average intra‐assessor cardiac output difference improved from 17% (95% CI 4–25) to 5% (95% CI 0–11, P_t‐test = 0.02). Analysis of 52 cardiac output assessments in 21 ED patients demonstrated excellent interassessor correlation (r = 0.96, 95% CI 0.90–0.98, P < 0.001). The average interassessor difference in cardiac output and index was 0.2 L/min (4%, 95% CI 3–6) and 0.1 L/min/m² (4%, 95% CI 2–6), respectively. Conclusion: Emergency physicians with no prior ultrasonographic experience can be trained to obtain reliable cardiac output estimations upon conscious ED patients with the USCOM over the course of 20 patient assessments.