Chagas disease reactivation in rheumatologic patients: association with immunosuppressive therapy and humoral response

Clinical Rheumatology - Evidence for Chagas disease reactivation (CDR) in rheumatologic patients under rheumatologic treatments (RTs) is scarce. To screen and follow-up patients with rheumatic...     

INAUGURAL ARTICLE by a Recently Elected Academy Member:Plant immunity: Rice XA21-mediated resistance to bacterial infection

In this article, we describe the development of the plant immunity field, starting with efforts to understand the genetic basis for disease resistance, which ∼30 y ago led to the discovery of diverse classes of immune receptors that recognize and respond to infectious microbes. We focus on knowledge gained from studies of the rice XA21 immune receptor that recognizes RaxX (required for activation of XA21 mediated immunity X), a sulfated microbial peptide secreted by the gram-negative bacterium Xanthomonas oryzae pv. oryzae. XA21 is representative of a large class of plant and animal immune receptors that recognize and respond to conserved microbial molecules. We highlight the complexity of this large class of receptors in plants, discuss a possible role for RaxX in Xanthomonas biology, and draw attention to the important role of sulfotyrosine in mediating receptor–ligand interactions.

Perception of extracellular signals by cell-surface receptors is of central importance to eukaryotic development and immunity. For example, in the absence of an adaptive immune system, plants rely on a repertoire of innate immune receptors to recognize potential pathogens and initiate defensive responses. A key research focus of the P.R. laboratory is to understand the principles and mechanisms that underlie the processes governing the immune response.Here we describe our 30-y effort to dissect the genetic and molecular basis of the innate immune response in the staple food crop and model organism rice Oryza sativa.     

Major hepatic resection for hilar cholangiocarcinoma: analysis of 46 patients

HYPOTHESIS: Major hepatectomy, bile duct resection, and regional lymphadenectomy for hilar cholangiocarcinoma are associated with actual long-term (>5 years) survival. DESIGN: Retrospective outcome study. SETTING: Single tertiary referral institution. PATIENTS: Between 1979 and 1997, 46 consecutive patients had resection of hilar cholangiocarcinoma by major hepatectomy, bile duct resection, and regional lymphadenectomy. MAIN OUTCOME MEASURES: Overall survival and tumor recurrence were correlated to clinicopathological factors, operative morbidity, and mortality. RESULTS: Twenty-five patients underwent left hepatectomy, 17 underwent right hepatectomy, and 4 had extended right hepatectomy. Eighteen patients underwent resection of segment 1. Negative (R0) resection margins were achieved in 37 patients (80%). The operative mortality rate was 9%, and the surgical morbidity rate was 52%. Actual 1-year, 3-year, and 5-year survival rates were 80%, 39%, and 26%, respectively. Factors adversely associated with patient survival rates included: male sex, lymph node metastases, tumor grade 3 or 4, elevated direct serum bilirubin level at diagnosis, elevated preoperative activated partial thromboplastin time, and more than 4 U of red blood cells transfused perioperatively. Tumor size and R0 resection approached significance for survival. Factors associated with tumor recurrence included: male sex, tumor grade 3 or 4, a low hemoglobin level both at diagnosis and preoperatively, and a low preoperative prothrombin time and low alkaline phosphatase level at diagnosis and preoperatively. Median time to recurrence was 3.6 years. Tumor recurrence was predominantly local and regional. CONCLUSIONS: The actual 5-year survival rate of 26% justifies major partial hepatectomy, bile duct resection, and regional lymphadenectomy for hilar cholangiocarcinoma. The high frequency of local and regional recurrence warrants investigation of adjuvant therapy.     

Hepatitis C: risk factors

Risk factors associated to at least 50% of hepatitis C cases are blood transfusion and injection-drug use. Less important factors are high-risk sexual behavior, job appointment in a healthcare setting and hemodialysis. Intra-familial and perinatal transmission are minor contributors to the overall prevalence of infection. The role of tattooing, acupuncture and piercing in hepatitis C transmission is controversial. There is still an important number of cases in whom no risk factor can be identified.     

Cellular basis for progesterone neuroprotection in the injured spinal cord

Progesterone (PROG) exerts beneficial and neuroprotective effects in the injured central and peripheral nervous system. In the present work, we examine PROG effects on three measures of neuronal function under negative regulation (choline acetyltransferase [ChAT] and Na,K-ATPase) or stimulated (growth-associated protein [GAP-43]) after acute spinal cord transection injury in rats. As expected, spinal cord injury reduced ChAT immunostaining intensity of ventral horn neurons. A 3-day course of intensive PROG treatment of transected rats restored ChAT immunoreactivity, as assessed by frequency histograms that recorded shifts from predominantly light neuronal staining to medium, dark or intense staining typical of control rats. Transection also reduced the expression of the mRNA for the alpha3 catalytic and beta1 regulatory subunits of neuronal Na,K-ATPase, whereas PROG treatment restored both subunit mRNA to normal levels. Additionally, the upregulation observed for GAP-43 mRNA in ventral horn neurons in spinal cord-transected rats, was further enhanced by PROG administration. In no case did PROG modify ChAT immunoreactivity, Na,K-ATPase subunit mRNA or GAP-43 mRNA in control, sham-operated rats. Further, the PROG-mediated effects on these three markers were observed in large, presumably Lamina IX motoneurons, as well as in smaller neurons measuring approximately <500 micro2. Overall, the stimulatory effects of PROG on ChAT appears to replenish acetylcholine, with its stimulatory effects on Na,K-ATPase seems capable of restoring membrane potential, ion transport and nutrient uptake. PROG effects on GAP-43 also appear to accelerate reparative responses to injury. As the cellular basis for PROG neuroprotection becomes better understood it may prove of therapeutic benefit to spinal cord injury patients.     

Parasite biodiversity in Rattus spp caught in wet markets

Rattus spp trapped in wet markets in Quiapo, Manila and Balayan, Batangas had ectoparasites, Echinolaelaps echidnius (mite), and Polyplax spinulosa (louse). The endoparasites identified were Hymenolepis diminuta; the acanthocephalan Moniliformis moniliformis; Taenia taeniaeformis strobilocercus larvae and Capillaria hepatica in liver; Trichosomoides crassicauda of the urinary bladder; Sarcocystis sp of muscle tissue; and two different species of stronglyloid-looking intestinal nematodes. Rats had 100% infection with C. hepatica and T. taeniaeformis, exhibiting high parasitemia. The co-existence of rats with diverse parasitic species is reflective of the host's capability to support parasites' behavioral, physiological, and developmental needs. Despite heavy infection with intestinal parasites, and marked hepatic tissue damage owing to severe capillariasis and strobilocercus larval infection, all rats appeared healthy and agile, suggestive of a well-established rat host-parasite relationship. In view of the diversity and zoonotic nature of rat parasites, and the impoverished conditions prevailing in communities where Rattus spp survive and proliferate, they can readily facilitate parasite transmission to humans and other susceptible animal hosts.     

Cell culture protection and<Emphasis Type="Italic">in vivo</Emphasis> neuroprotective capacity of flavonoids

Flavonoids are an important group of recognized antioxidants ubiquitous in fruits, vegetables and herbs. There are epidemiological evidences for the stroke-protecting capacity of flavonoids and while the neuroprotective power of complex extracts rich in flavonoids like those of Ginkgo biloba, green tea or lyophilized red wine have been demonstrated in several studies, neuroprotection by individual flavonoids has been poorly studiedin vivo. The neuroprotective capacity of individual flavonoids was studied in PC12 cells in culture and in a model of permanent focal ischemia (permanent Middle Cerebral Artery Occlusion — pMCAO). In thein vivo experiments, flavonoids were administered in lecithin preparations to facilitate the crossing of the blood brain barrier.