Decreased necrotizing fasciitis capacity caused by a single nucleotide mutation that alters a multiple gene virulence axis.

Single-nucleotide changes are the most common cause of natural genetic variation among members of the same species, but there is remarkably little information bearing on how they alter bacterial virulence. We recently discovered a single-nucleotide mutation in the group A Streptococcus genome that is epidemiologically associated with decreased human necrotizing fasciitis ("flesh-eating disease"). Working from this clinical observation, we find that wild-type mtsR function is required for group A Streptococcus to cause necrotizing fasciitis in mice and nonhuman primates. Expression microarray analysis revealed that mtsR inactivation results in overexpression of PrsA, a chaperonin involved in posttranslational maturation of SpeB, an extracellular cysteine protease. Isogenic mutant strains that overexpress prsA or lack speB had decreased secreted protease activity in vivo and recapitulated the necrotizing fasciitis-negative phenotype of the DeltamtsR mutant strain in mice and monkeys. mtsR inactivation results in increased PrsA expression, which in turn causes decreased SpeB secreted protease activity and reduced necrotizing fasciitis capacity. Thus, a naturally occurring single-nucleotide mutation dramatically alters virulence by dysregulating a multiple gene virulence axis. Our discovery has broad implications for the confluence of population genomics and molecular pathogenesis research.

Blindness and auditory impairment caused by loss of the sodium bicarbonate cotransporter NBC3.

Normal sensory transduction requires the efficient disposal of acid (H+) generated by neuronal and sensory receptor activity. Multiple highly sensitive transport mechanisms have evolved in prokaryotic and eukaryotic organisms to maintain acidity within strict limits. It is currently assumed that the multiplicity of these processes provides a biological robustness. Here we report that the visual and auditory systems have a specific requirement for H+ disposal mediated by the sodium bicarbonate cotransporter NBC3 (refs. 7,8). Mice lacking NBC3 develop blindness and auditory impairment because of degeneration of sensory receptors in the eye and inner ear as in Usher syndrome. Our results indicate that in certain sensory organs, in which the requirement to transduce specific environmental signals with speed, sensitivity and reliability is paramount, the choice of the H+ disposal mechanism used is limited.

Evaluation of the toxicity of intravenous delivery of auroshell particles (gold-silica nanoshells).

Gold nanoshells (155 nm in diameter with a coating of polyethylene glycol 5000) were evaluated for preclinical biocompatibility, toxicity, and biodistribution as part of a program to develop an injectable device for use in the photothermal ablation of tumors. The evaluation started with a complete good laboratory practice (GLP) compliant International Organization for Standardization (ISO)-10993 biocompatibility program, including cytotoxicity, pyrogenicity (US Pharmacopeia [USP] method in the rabbit), genotoxicity (bacterial mutagenicity, chromosomal aberration assay in Chinese hamster ovary cells, and in vivo mouse micronucleus), in vitro hemolysis, intracutaneous reactivity in the rabbit, sensitization (in the guinea pig maximization assay), and USP/ISO acute systemic toxicity in the mouse. There was no indication of toxicity in any of the studies. Subsequently, nanoshells were evaluated in vivo by intravenous (iv) infusion using a trehalose/water solution in a series of studies in mice, Sprague-Dawley rats, and Beagle dogs to assess toxicity for time durations of up to 404 days. Over the course of 14 GLP studies, the gold nanoshells were well tolerated and, when injected iv, no toxicities or bioincompatibilities were identified.

Mycobacterium kansasii Isolated from Tuberculinpositive Rhesus Macaques (Macaca mulatta) in the Absence of Disease.

Mycobacterial infections are of primary health concern in NHP colonies in biomedical research. NHP are constantly monitored and screened for Mycobacterium spp. We report 6 Chinese-origin rhesus macaques infected with Mycobacterium kansasii that exhibited positive tuberculin skin tests in the absence of disease. Two of these macaques were being used for research purposes; the remaining 4 macaques were residing at the contract quarantine company. Histopathology and acid-fast staining of fixed tissues from all macaques showed that all were free of disease. Thoracic radiographs were negative for any signs of disease or infection. Samples from bronchial lavage and tissues including lung, spleen, hilar and mesenteric lymph nodes tested negative by PCR assay for Mycobacterium spp. One of the research macaques tested culture-positive for M. kansasii and a poorly characterized M. avium complex organism. One macaque from the contract quarantine facility tested culture positive for M. kansasii. Genomic testing and target gene RNA expression analysis of the 2 M. kansasii isolates were performed to evaluate possible kinship and affected genes that might contribute to susceptibility to mycobacterial infection. Genotyping of the 2 isolates revealed 2 genetically distinct strains (strains 1 and 4). The presence of positive tuberculin skin tests in the absence of disease raises serious concerns regarding diagnostic methods used for infected NHP.

Disruption of the NAD(P)H:quinone oxidoreductase 1 (NQO1) gene in mice causes myelogenous hyperplasia.

NAD(P)H:quinone oxidoreductase1 (NQO1) is a cytosolic protein that reduces and detoxifies quinones and their derivatives, thus protecting cells against redox cycling and oxidative stress. Disruption of the NQO1 gene in mice caused myeloid hyperplasia of bone marrow and highly significant increases in blood neutrophils, eosinophils, and basophils. NQO1-null mice also showed a decrease in lymphocytes and WBCs as compared with wild-type mice. Various techniques also demonstrated an increase in megakaryocytes without an increase in blood platelets. Histological analysis of liver, kidney, spleen, and thymus did not demonstrate a difference between wild-type and NQO1-null mice or a sign of infection. Blood cultures and urine analysis also did not demonstrate any sign of infection in NQO1-null and wild-type mice. Additional analysis of the bone marrow from NQO1-null mice revealed that loss of NQO1 alters the intracellular redox status because of accumulation of NAD(P)H, cofactors for NQO1. This causes a reduction in the levels of pyridine nucleotides and tumor suppressor proteins p53 and p73, and a decrease in apoptosis. The decrease in apoptosis causes myelogenous hyperplasia in NQO1-null mice. These results demonstrate that NQO1 acts as an endogenous factor in the protection against myelogenous hyperplasia. This is significant because 2-4% of human individuals without known abnormalities, and >25% of individuals with benzene poisoning and acute myelogenic leukemia are homozygous for a mutant allele (P187S) of NQO1 and lack NQO1 protein/activity.

Bone Marker-Directed Dosing of Zoledronic Acid for the Prevention of Skeletal Complications in Patients with Multiple Myeloma: Results of the Z-MARK Study.

PURPOSE: Zoledronic acid (ZOL) given every 3 to 4 weeks can reduce skeletal-related events (SRE) in patients with bone lesions from multiple myeloma. This study evaluated efficacy and safety of less-frequent ZOL dosing based on bone turnover markers in patients with 1 to 2 years of prior bisphosphonate therapy. EXPERIMENTAL DESIGN: Patients received ZOL (4 mg) every 4 or 12 weeks based on urinary N-telopeptide of type 1 collagen (uNTX) levels (every 4 weeks if uNTX ≥50 nmol/mmol creatinine, every 12 weeks if uNTX < 50). RESULTS: Of 121 patients enrolled (mean age, 63.8 years; median follow-up, 21 months), 4 patients started ZOL every 4 weeks and 117 received ZOL every 12 weeks based on uNTX at study entry. All 4 patients who initiated ZOL every 4 weeks switched to every 12 weeks due to decreased uNTX. Thirty-eight of 117 patients who initiated ZOL every 12 weeks switched to ZOL every 4 weeks due to disease progression (n = 20), increased uNTX (n = 14), and SREs (n = 4). Overall SRE incidence was low; 7 (5.8%) and 5 (4.9%) patients experienced an SRE during years 1 and 2, respectively. Mean (SD) SRE rate at year 2 was 0.01 (0.03) per person-year. The 2-year incidence rate for osteonecrosis of jaw was 3.3%. Four deaths were reported, none related to ZOL. CONCLUSIONS: Less frequent ZOL dosing (every 12 weeks over 2 years) maintains a low SRE rate and can be safely administered for up to 4 years.

Predicting psychological distress in patients with leukaemia and lymphoma.

This study examines the relationship between coping style, quality of life (QOL) and psychological distress in a sample of patients with leukaemia and lymphoma. Fifty-one consecutive in-patients, day cases and haematology out-patient attenders entered the study and completed a 10-item self-report questionnaire, the Hospital Anxiety and Depression Scale (HADS), the Mental Adjustment to Cancer Scale (MACS) and the Schedule for the Evaluation of Individual Quality of Life (SEIQOL). Fifty-one percent of patients reached caseness for moderate distress. Fourteen percent of patients reached caseness for severe distress. Twenty-seven percent of patients were identified as having adjusted poorly to their diagnosis having low scores on the Fighting Spirit subscale of the MAC and high scores on the Hopeless/Helpless subscale. There was a significant association between patients who scored highly on the HADS and dissatisfaction with the information provided. Use of a logistic regression model showed that those patients most likely to be suffering from severe psychological distress were those with a worse coping style, measured by MAC. The clinical implications of these findings are discussed.

Spontaneous Renal Cell Carcinoma in a New Zealand White Rabbit.

The incidence of primary renal neoplasia in animals is quite low. Carcinomas are the most common primary renal tumors of dogs, cattle, and sheep. Among rabbit tumors, only uterine adenocarcinomas occur more frequently than do embryonal nephromas. However, spontaneous renal cell carcinomas in laboratory rabbits have only been reported once previously. We here report a second occurrence of a renal cell carcinoma in the laboratory rabbit.

Individual quality of life in patients with leukaemia and lymphoma.

With increasingly sophisticated chemotherapy regimes being prescribed the quality of life of cancer patients has become a key outcome measure. Little has been reported concerning the experience of patients with haematological malignancy receiving chemotherapy. The objective of this study was to evaluate the clinical usefulness of a novel quality of life measure-the Schedule for the Evaluation of Individual Quality of Life-Direct Weighting (SEIQoL-DW) in a sample of patients with either leukaemia or lymphoma. Fifty-one patients from the haematology clinic and in-patient unit at The Royal Devon and Exeter Hospital completed the SEIQoL-DW; in addition, each patient completed the Hospital Anxiety and Depression Scale (HADS) and a ten item questionnaire covering aspects of their treatment and satisfaction with information provided. The practical application of the SEIQoL-DW is described and two patients quality of life profiles are illustrated for comparison. The relationship between quality of life, satisfaction with information provided and psychological distress as measured by the HADS is discussed.