Binding of conserved islet peptides by human and murine MHC class II molecules associated with susceptibility to type I diabetes

The major histocompatibility complex (MHC) is the most important susceptibility locus for type I diabetes in humans and NOD mice. NOD mice express a single MHC class II molecule (I-Ag7) which carries a unique beta chain sequence. In humans, DQ alleles that encode DQ8 and DQ2 confer the highest risk for the disease. Soluble DQ8 and I-Ag7 were used to directly compare the binding specificity of these MHC molecules. Peptides from three islet antigens--insulin, GAD 65 and HSP 60--bound to both CQ8 and I-Ag7. These peptides included epitopes that are immunodominant in NOD mice, namely insulin (9-23), GAD (206-220) and HSP 60 (441-460). All of these peptide sequences are highly conserved between the human and murine antigens. The binding specificity of DQ8 and I-Ag7 was similar, but not identical, since two peptides eluted from splenocytes of NOD mice did not bind to DQ8. DQ8 formed long-lived complexes with the majority of these peptides, indicating that DQ8 is not a poor peptide binder. These results demonstrate functional similarities between human and murine MHC class II molecules that confer susceptibility to type I diabetes.     

Pathologic evaluation of sentinel lymph nodes in colorectal carcinoma

BACKGROUND: The identification of lymph node metastases in colorectal resection specimens is necessary for accurate tumor staging. However, routine lymph node dissection by the pathologist yields only a subset of nodes removed surgically and may not include those nodes most directly in the path of lymphatic drainage from the tumor. Intraoperative mapping of such sentinel lymph nodes (SLNs) has been reported in cases of melanoma and breast cancer. We applied a similar method to cases of colorectal carcinoma, with emphasis on the pathology of the SLNs. METHODS: Eighty-three consecutive patients with colorectal carcinoma were evaluated after intraoperative injection of 1 to 2 mL of 1% isosulfan blue dye (Lymphazurin) into the peritumoral subserosa. Blue-stained lymph nodes were suture-tagged by the surgeon within minutes of the injection for identification by the pathologist, and a standard resection was performed. Designated SLNs were sectioned at 10 levels through the block; a cytokeratin immunostain (AE1) was also obtained. To evaluate the possibility that increased detection of metastases in the SLN might be solely due to increased histologic sampling, all initially negative non-SLNs in the first 25 cases were sectioned also at 10 levels. RESULTS: Sentinel lymph nodes were identified intraoperatively in 82 (99%) of 83 patients and accounted for 152 (11.9%) of 1275 lymph nodes recovered, with an average of 1.9 SLNs per patient. A total of 99 positive lymph nodes (38 positive SLNs and 61 positive non-SLNs) were identified in 34 node-positive patients. The SLNs were the only site of metastasis in 17 patients (50%), while 14 patients (41%) had both positive SLNs and non-SLNs. Three patients (9%) had positive non-SLNs with negative SLNs, representing skip metastases. In patients with positive SLNs, 91 (19%) of 474 total lymph nodes and 53 (12%) of 436 non-SLNs were positive for metastasis. In patients with negative SLNs, 8 (1%) of 801 total lymph nodes and 8 (1.2%) of 687 non-SLNs were positive for metastasis. Multilevel sections of 330 initially negative non-SLNs in the first 25 patients yielded only 2 additional positive nodes (0. 6%). All patients with positive SLNs were correctly staged by a combination of 4 representative levels through the SLN(s) together with a single cytokeratin immunostain. CONCLUSIONS: Intraoperative mapping of SLNs in colorectal carcinoma identifies lymph nodes likely to contain metastases. Focused pathologic evaluation of the 1 to 4 SLNs so identified can improve the accuracy of pathologic staging.     

Neuronal and inducible nitric oxide synthase expressions and activities in the hippocampi and cortices of young adult,aged cognitively unimpaired,and impaired Long-Evans rats

Nitric oxide (NO) is a neurosignaling molecule that appears to play a significant role in learning and memory. This molecule has also been implicated in neurotoxicity due to its oxidative properties. Previous experiments from our laboratories have demonstrated elevated hippocampal and cortical neuronal nitric oxide synthase (NOS) mRNA levels in aged cognitively unimpaired and impaired Long-Evans rats, which could represent either increased neuronal NOS activity thereby leading to NO-mediated neurotoxicity, or a compensatory response by aged neurones to maintain physiological nitric oxide output. The current study measured the protein expression and activity levels of neuronal and inducible NOS in young adult (6 months) and aged (24-26 months) Long-Evans rats by means of western blotting and NOS activity assay. Aged animals were assigned as either cognitively unimpaired or aged with moderate cognitive impairments based on their performances in the Morris water maze behavioural task. Our results showed that hippocampal and cortical neuronal NOS expressions were significantly decreased in aged animals. These aged animals also exhibited increased hippocampal and cortical inducible NOS expressions. Between the two aged animal groups, cognitively impaired rats showed significantly lower hippocampal and cortical neuronal but higher hippocampal inducible NOS expressions. Young adult rats exhibited significantly higher hippocampal and cortical NOS activities than the aged animals. Aged animals with cognitive deficits showed significantly lower hippocampal NOS activity than cognitively unimpaired aged rats.Our data indicate that aging is associated with a decline in neuronal but elevated inducible NOS functioning in brain areas involved in learning and memory. These phenomena could contribute to the cognitive deficits observed in a sub-population of aged animals.     

Use of the SOS chromotest, the Ames-fluctuation test and the newt micronucleus test to study the genotoxicity of four trihalomethanes

Three short-term assays (the SOS chromotest, the Ames-fluctuationtest and the newt micronucleus test) were carried out to evaluatethe genotoxicity of four trihalomethanes (chloroform, bromodichloromethane,chlorodibromomethane and bromoform). With the SOS chromotest,all the chemicals studied except chloroform were found to induceprimary DNA damage in Escherichia coli PQ37. In the Ames-fluctuationtest, only bromoform showed mutagenic activity on Salmonellatyphimurium strain TA100. The newt micronucleus assay detecteda clastogenic effect on the peripheral blood erythrocytes ofPleurodeles waltl larvae for bromodichloromethane and bromoform.It appeared that the presence of bromine substituent(s) generallyled to significant genotoxic activity. Moreover, the use ofthe metabolic system significantly increased the genotoxicityof the brominated trihalomethanes in the SOS chromotest. Unlikeprevious investigations in which the SOS chromotest was alwaysthe least interesting assay, this study exhibited the good efficiencyof this in vitro test on E.coli for the detection of trihalomethaneswith bromine substituents. ⁴To whom correspondence should be addressed at: Institut Pasteur de Lille, Laboratoire de Toxicologie génétique, 1 rue du Professeur Calmette, BP 245, 59019 Lille Cedex, France     

Bactericidal activity of human lactoferrin: sensitivity of a variety of microorganisms

Lactoferrin is an iron-binding protein that has been detected in secretions that bathe human mucosal tissues. Previous studies have shown that, when this protein is in the iron-free state, it is capable of a direct bactericidal effect on Streptococcus mutans and Vibrio cholerae. The present study demonstrates variable susceptibilities for a variety of different microorganisms. The list of susceptible organisms includes gram-positive and gram-negative microbes, rods and cocci, facultative anaerobes, and aerotolerant anaerobes. Similar morphological and physiological types are represented among the lalctoferrin-resistant bacteria. S. mutans was more resistant to lactoferrin when grown on a sucrose-contaning medium than when it was grown on brain heart infusion broth without added scurose. When a lactoferrin-sensitive, avirulent strain of Streptococcus pneumoniae was passed through mice, the resultant virulent culture became lactoferrin resistant. Since organisms of the same species and even of the same strain (S. pneumoniae) can differ in susceptibility to lactoferrin, it appears that accessibility to the lactoferrin target site may account for differences in susceptibility. It appears that there may be a relation between virulence and resistance to lactoferrin.     

Assessing the Feasibility and Effectiveness of an App in Improving Knowledge on Oral Cancer—an Interventional Study

Although current oral health care initiatives have proved to be quite successful, a great number of individuals are unaware of how their choice of daily activities compromises their oral health. That is why newer technologies like WhatsApp can definitely serve as a platform to communicate dental advice, thereby strengthening the bridge between health and technology. The objective of the study was to assess the effectiveness of WhatsApp as a tool for providing health education on tobacco and oral cancer as compared to the conventional health education via PowerPoint. The study was a cluster randomized controlled trial, single-center study. The students of 18–24 years of age with WhatsApp application active in their mobile phones were included. Four classes with 182 students were randomly divided into intervention and control groups. Control group received health education on oral cancer using a PowerPoint presentation weekly, for a total of 4 weeks. Intervention group received health education through WhatsApp messaging thrice a week for 4 weeks. Pre- and post-health education knowledge scores were assessed using a questionnaire and compared using unpaired and paired two-sample t tests. Statistically significant increase in knowledge scores was seen in both groups, with highly significant improvement in the intervention group (p value = 0.00). Intergroup comparison showed no significant difference in knowledge scores at baseline, but a significant difference in post intervention knowledge scores (t = -15.05 p<0.001) WhatsApp can be a more effective tool for providing dental education on tobacco and oral cancer as compared to conventional audio-visual aids.     

CLINICAL APPLICATION OF FLOW CYTOMETRY IN LIVE RELATED DONOR RENAL TRANSPLANTATION

To monitor the activity of the humoral component in graft dysfunction following renal transplantation using live related donors, flowcytometric cross-match procedure was adopted. Antidonor antibodies were detected in the sera of both pre- and post-transplant patients using conventional serological cytotoxicity cross-match and flowcytometric cross-match assays. In the 52 pretransplant samples no significant differences were observed in flowcytometric and cytotoxicity tests except in 2 secondary transplant cases which were negative by cytotoxicity test. However, in post-transplant samples, floweytometry was found to be a more objective and useful test than cytotoxicity testing in distinguishing 6 out of 7 mild acute-graft-rejection episodes. Both tests were found to be negative in alt 5 cases of cyclosporin-A nephrotoxicity, 7 cases of acute tubular necrosis and 10 out of 11 cases of chronic rejection.KEY WORDS: Flowcytometry, Cross-match, Graft dysfunction, Kidney transplantation     

Comparison of mobile lithotripters at one institution: healthtronics lithotron, Dornier MFL-5000, and Dornier Doli

BACKGROUND AND PURPOSE: Extracorporeal shockwave lithotripsy (SWL) has replaced most surgical and endourologic procedures for upper urinary tract stone disease. Our institution contracted with mobile lithotripter companies to provide SWL. We reviewed the outcomes of 50 patients treated on each machine with regard to efficacy, complications, and retreatment rates. PATIENTS AND METHODS: One hundred fifty patients over 21 years of age were treated at Ochsner Foundation Hospital from April 1995 through June 1998. All stones were in either the kidney or the upper ureter, and all were <20 mm. Three mobile lithotripters-the Dornier MFL-5000 (4/95-9/96), the Dornier Doli (9/96-11/97), and the HealthTronics Lithotron (12/97-4/98)-were each used to treat 50 patients. Conscious monitored intravenous sedation was used in all patients. Post-treatment evaluations were made at 2 weeks, 1 month, and 3 months. RESULTS: A successful outcome (stone free or fragments <4 mm) was achieved in 72% (MLF-5000), 68% (Doli), and 80% (Lithotron) of patients (P = 0.39). Treatments that were followed by retreatments or other further procedures (ureteroscopy or percutaneous nephrolithotomy) were counted as failures. The retreatment rate was 10%, 22%, and 10%, respectively. There were three significant complications with the Doli unit: two large perirenal hematomas (4%) and one delayed splenic rupture in a patient with a history of pelvic surgery that necessitated transfusions and urgent splenectomy. The minor complication rates with all three lithotripters were similar to those reported in the literature. The three-month efficiency quotients were 0.55 for the Lithotron and MFL-5000 and 0.41 for the Doli. CONCLUSIONS: Statistically equivalent success rates were achieved with all three machines. The electromagnetic unit (Doli) had higher rates of retreatment and significant complications than the electrohydraulic lithotripters (MFL-5000, Lithotron).     

Prevention of Alzheimer's disease

Delaying the emergence of Alzheimer's disease (AD) symptoms by 5 to 10 years would have a significant public health impact in the long term. Data generated from large scale epidemiological studies on risk as well as protective factors for AD are leading to treatment strategies that can be tested in transgenic animal models as well as human populations at higher genetic risk.