Reversible skeletal abnormalities in gamma-glutamyl transpeptidase-deficient mice

Gamma-glutamyl transpeptidase (GGT) is a widely distributed ectopeptidase responsible for the degradation of glutathione in the gamma-glutamyl cycle. This cycle is implicated in the metabolism of cysteine, and absence of GGT causes a severe intracellular decrease in this amino acid. GGT-deficient (GGT-/-) mice have multiple metabolic abnormalities and are dwarf. We show here that this latter phenotype is due to a decreased of the growth plate cartilage total height resulting from a proliferative defect of chondrocytes. In addition, analysis of vertebrae and tibiae of GGT-/- mice revealed a severe osteopenia. Histomorphometric studies showed that this low bone mass phenotype results from an increased osteoclast number and activity as well as from a marked decrease in osteoblast activity. Interestingly, neither osteoblasts, osteoclasts, nor chondrocytes express GGT, suggesting that the observed defects are secondary to other abnormalities. N-acetylcysteine supplementation has been shown to reverse the metabolic abnormalities of the GGT-/- mice and in particular to restore the level of IGF-1 and sex steroids in these mice. Consistent with these previous observations, N-acetylcysteine treatment of GGT-/- mice ameliorates their skeletal abnormalities by normalizing chondrocytes proliferation and osteoblastic function. In contrast, resorbtion parameters are only partially normalized in GGT-/- N-acetylcysteine-treated mice, suggesting that GGT regulates osteoclast biology at least partly independently of these hormones. These results establish the importance of cysteine metabolism for the regulation of bone remodeling and longitudinal growth.     

Appropriateness of therapy for active Crohn's disease: Results of a multidisciplinary international expert panel—EPACT II

The increasing number of trials testing management strategies for luminal Crohn's disease (CD) has not filled all the gaps in our knowledge and thus, in clinical practice, many decisions for CD patients have to be taken without the benefit of high-quality evidence.MethodsA multidisciplinary European expert panel used the RAND Appropriateness Method to develop and rate explicit criteria for the management of individual patients with active, steroid-dependent (ST-D) and steroid-refractory (ST-R) CD.ResultsOverall, 296 indications pertaining to mild-to-moderate, severe, ST-D, and ST-R CD were rated. In anti-TNF naïve patients, budesonide and prednisone were found to be appropriate for mild-moderate CD, and infliximab (IFX) was appropriate when these had previously failed or had not been tolerated. In patients with a prior successful treatment by IFX, this drug, with or without co-administration of a thiopurine analog, was favoured. Other anti-TNFs were appropriate in the presence of intolerance or resistance to IFX. High-dose steroids, IFX or adalimumab were appropriate in severe active CD. For the 105 indications for ST-D or ST-R disease, the panel considered the thiopurine analogs, methotrexate, IFX, adalimumab, and surgery for limited resection, to be appropriate, depending on the outcome of prior therapies. Anti-TNFs were generally considered appropriate in ST-R.ConclusionSteroids, including budesonide for mild-to-moderate CD, remain the first-line therapy for active luminal CD. Anti-TNFs, in particular IFX as shown by the amount of available evidence, remain the second-line therapy for most indications. Thiopurine analogs, methotrexate and anti-TNFs are favoured in ST-D patients and ST-R patients.     

Outcome of diabetic foot infections treated conservatively: a retrospective cohort study with long-term follow-up

BACKGROUND: Diabetic foot lesion is associated with increased morbidity and high resource use. Although early amputation has been advocated in case of osteomyelitis, conservative treatment is a more attractive alternative. OBJECTIVE: To identify criteria predictive of failure of conservative treatment of diabetic foot ulcer at time of admission to the hospital. METHODS: We conducted a 5-year retrospective cohort study with prospective long-term follow-up of all diabetic patients admitted for a foot lesion at a large (1600-bed) teaching institution. Predetermined criteria were used for the diagnosis and classification of diabetic foot lesions (Wagner classification). Study variables included patient demographics and clinical parameters related to infection and diabetes. The average follow-up after hospital discharge was 2 years. Failure of conservative treatment was the main outcome measure. Independent predictor variables were selected by logistic regression analysis. RESULTS: A total of 120 diabetic patients were admitted for foot lesions; complications of contiguous osteomyelitis, deep tissue involvement, and/or gangrenous lesions occurred in 78 (74%) of the 105 patients for whom charts were available. Fourteen patients (13%) underwent immediate amputation. Conservative treatment was successful for 57 (63%) of the 91 remaining patients. Success was achieved in 21 (81%) of 26 patients presenting with skin ulcer, 35 (70%) of 50 patients with deep tissue infection or suspected osteomyelitis, and 1 (7%) of 15 patients with gangrene (P<.001, chi2 for trend). Independent factors predictive of failure were the presence of fever (odds ratio [OR]=1.1 per degrees Celcius; 95% confidence interval [CI], 1.0-1.2) and increased serum creatinine level (OR=1.002 per micromoles per liter; 95% CI, 1.0020-1.0021) on admission, prior hospitalization for diabetic foot lesion (OR=1.4; 95% CI, 1.2-1.6), and gangrenous lesion (OR=1.8; 95% CI, 1.5-2.2). Other patient characteristics, demographics, duration of diabetes mellitus, neutrophil count, or the anatomical site of the lesion failed to predict outcome. CONCLUSIONS: Conservative treatment, including prolonged, culture-guided parenteral and oral antibiotics, is successful without amputation in a large proportion of diabetic patients admitted for a foot skin ulcer or suspected osteomyelitis. Future studies comparing early amputation with novel therapeutic strategies for severe diabetic foot infection should take into account currently identified factors that predicted failure of conservative treatment on admission to the hospital.     

Do we know all there is to know about Familial Adenomatous Polyposis?

Familial Adenomatous Polyposis (FAP) and Attenuated FAP (AFAP) are caused by a germline mutation in the Adenomatous polyposis coli (APC) gene. Recently, a new pathway characterized by a biallelic mutation in the MYH gene, with a recessive model of inheritance was discovered for this inherited syndrome. This report describes a Tunisian patient with an attenuated FAP phenotype, presenting seven colon polyps and an adenocarcinoma but no detectable germline mutations in the FAP target genes. A well known somatic mutation was found in the APC mutation cluster region (MCR). This case shows that further studies are needed to fully understand all the pathways of the FAP syndrome.     

Adaptive response of Yersinia pestis to extracellular effectors of innate immunity during bubonic plague

Yersinia pestis causes bubonic plague, characterized by an enlarged, painful lymph node, termed a bubo, that develops after bacterial dissemination from a fleabite site. In susceptible animals, the bacteria rapidly escape containment in the lymph node, spread systemically through the blood, and produce fatal sepsis. The fulminant progression of disease has been largely ascribed to the ability of Y. pestis to avoid phagocytosis and exposure to antimicrobial effectors of innate immunity. In vivo microarray analysis of Y. pestis gene expression, however, revealed an adaptive response to nitric oxide (NO)-derived reactive nitrogen species and to iron limitation in the extracellular environment of the bubo. Polymorphonuclear neutrophils recruited to the infected lymph node expressed abundant inducible NO synthase, and several Y. pestis homologs of genes involved in the protective response to reactive nitrogen species were up-regulated in the bubo. Mutation of one of these genes, which encodes the Hmp flavohemoglobin that detoxifies NO, attenuated virulence. Thus, the ability of Y. pestis to destroy immune cells and remain extracellular in the bubo appears to limit exposure to some but not all innate immune effectors. High NO levels induced during plague may also influence the developing adaptive immune response and contribute to septic shock.     

The genome sequence of the probiotic intestinal bacterium Lactobacillus johnsonii NCC 533

Lactobacillus johnsonii NCC 533 is a member of the acidophilus group of intestinal lactobacilli that has been extensively studied for their "probiotic" activities that include, pathogen inhibition, epithelial cell attachment, and immunomodulation. To gain insight into its physiology and identify genes potentially involved in interactions with the host, we sequenced and analyzed the 1.99-Mb genome of L. johnsonii NCC 533. Strikingly, the organism completely lacked genes encoding biosynthetic pathways for amino acids, purine nucleotides, and most cofactors. In apparent compensation, a remarkable number of uncommon and often duplicated amino acid permeases, peptidases, and phosphotransferase-type transporters were discovered, suggesting a strong dependency of NCC 533 on the host or other intestinal microbes to provide simple monomeric nutrients. Genome analysis also predicted an abundance (>12) of large and unusual cell-surface proteins, including fimbrial subunits, which may be involved in adhesion to glycoproteins or other components of mucin, a characteristic expected to affect persistence in the gastrointestinal tract (GIT). Three bile salt hydrolases and two bile acid transporters, proteins apparently critical for GIT survival, were also detected. In silico genome comparisons with the >95% complete genome sequence of the closely related Lactobacillus gasseri revealed extensive synteny punctuated by clear-cut insertions or deletions of single genes or operons. Many of these regions of difference appear to encode metabolic or structural components that could affect the organisms competitiveness or interactions with the GIT ecosystem.     

Role of the Yersinia pestis plasminogen activator in the incidence of distinct septicemic and bubonic forms of flea-borne plague

Yersinia pestis is transmitted by fleas and causes bubonic plague, characterized by severe local lymphadenitis that progresses rapidly to systemic infection and life-threatening septicemia. Here, we show that although flea-borne transmission usually leads to bubonic plague in mice, it can also lead to primary septicemic plague. However, intradermal injection of Y. pestis, commonly used to mimic transmission by fleabite, leads only to bubonic plague. A Y. pestis strain lacking the plasmid-encoded cell-surface plasminogen activator, which is avirulent by intradermal or s.c. injection, was able to cause fatal primary septicemic plague at low incidence, but not bubonic plague, when transmitted by fleas. The results clarify a long-standing uncertainty about the etiology of primary septicemic plague and support an evolutionary scenario in which plague first emerged as a flea-borne septicemic disease of limited transmissibility. Subsequent acquisition of the plasminogen activator gene by horizontal transfer enabled the bubonic form of disease and increased the potential for epidemic spread.     

Management of unsuccessful thrombolysis in acute massive pulmonary embolism

BACKGROUND: The management of patients with acute massive pulmonary embolism (PE) who do not respond to fibrinolytic therapy remains unclear. We aimed to compare rescue surgical embolectomy and repeat thrombolysis in patients who did not respond to thrombolysis. METHODS: We conducted a prospective single-center registry of PE patients who underwent thrombolytic therapy. Lack of response to thrombolysis within the first 36 h was prospectively defined as both persistent clinical instability and residual echocardiographic right ventricular dysfunction. Patients underwent surgical embolectomy or repeat thrombolysis, at the discretion of the attending physician. The clinical end point was a combined end point including recurrent PE, bleeding complications, or PE-related death, which was defined as death from recurrent PE or cardiogenic shock. Long-term adverse outcomes included death, recurrent thromboembolic events, and congestive heart failure. RESULTS: From January 1995 to January 2005, 488 PE patients underwent thrombolysis, of whom 40 (8.2%) did not respond to thrombolysis. Fourteen patients were treated by rescue surgical embolectomy, and 26 were treated by repeat thrombolysis. There was no significant difference in baseline characteristics between the two groups. The in-hospital course was uneventful in 11 of the surgically treated patients (79%) and in 8 patients (31%) treated by repeat thrombolysis (p = 0.004). There was a trend for higher mortality in the medical group than in the surgical group (10 vs 1 deaths, respectively; p = 0.07). There were significantly more recurrent PEs (fatal and nonfatal) in the repeat-thrombolysis group (35% vs 0%, respectively; p = 0.015). While no significant difference was observed in number of major bleeding events, all bleeding events in the repeat-thrombolysis group were fatal. The rate of uneventful long-term evolution was the same in the two groups. CONCLUSION: Rescue surgical embolectomy led to a better in-hospital course when compared with repeat thrombolysis in patients with massive PE who have not responded to thrombolysis. The transfer of patients who have not responded to thrombolysis to tertiary cardiac surgery centers could be considered as an alternative option.     

Evidence-based model for hand transmission during patient care and the role of improved practices

Hand cleansing is the primary action to reduce health-care-associated infection and cross-transmission of antimicrobial-resistant pathogens. Patient-to-patient transmission of pathogens via health-care workers' hands requires five sequential steps: (1) organisms are present on the patient's skin or have been shed onto fomites in the patient's immediate environment; (2) organisms must be transferred to health-care workers' hands; (3) organisms must be capable of surviving on health-care workers' hands for at least several minutes; (4) handwashing or hand antisepsis by the health-care worker must be inadequate or omitted entirely, or the agent used for hand hygiene inappropriate; and (5) the caregiver's contaminated hand(s) must come into direct contact with another patient or with a fomite in direct contact with the patient. We review the evidence supporting each of these steps and propose a dynamic model for hand hygiene research and education strategies, together with corresponding indications for hand hygiene during patient care.     

Outcome of treated advanced non-small cell lung cancer with and without central airway obstruction

OBJECTIVE: In patients with advanced non-small cell lung cancer (NSCLC) treated with chemotherapy, we compared survival in patients with treated central airway obstruction to those who did not have central airway obstruction. METHODS: One hundred forty-four patients with advanced and inoperable NSCLC were included. These consisted of 52 consecutive patients treated with therapeutic bronchoscopy plus chemotherapy with or without radiotherapy (group A) and 92 consecutive patients who did not have central airway obstruction treated with chemotherapy alone (group B). Chemotherapy consisted of cisplatin or carboplatin, and one third-generation chemotherapy agent. RESULTS: There was no significant difference in the survival of patients with and without central airway obstruction (p = 0.395). There was no influence of the histologic subtype on survival in both groups combined and also in each group separately. Median survival in patients belonging to group A was 8.4 months and those in group B was 8.2 months; 3-, 6-, and 12-month survival rates in patients in group A were 90%, 71%, and 40%, respectively, and those in group B were 82%, 63%, and 34%. CONCLUSION: Patients having advanced NSCLC with locally treated malignant central airway obstruction in combination with chemotherapy do not have a worse survival compared to those with advanced NSCLC without central airway obstruction. Therapeutic bronchoscopy should be offered to patients with NSCLC and central airway obstruction.