Interpreting the results of chemical stone analysis in the era of modern stone analysis techniques

INTRODUCTION AND OBJECTIVE: Stone analysis should be performed in all first-time stone formers. The preferred analytical procedures are Fourier-transform infrared spectroscopy (FT-IR) or X-ray diffraction (XRD). However, due to limited resources, chemical analysis (CA) is still in use throughout the world. The aim of the study was to compare FT-IR and CA in well matched stone specimens and characterize the pros and cons of CA. METHODS: In a prospective bi-center study, urinary stones were retrieved from 60 consecutive endoscopic procedures. In order to assure that identical stone samples were sent for analyses, the samples were analyzed initially by micro-computed tomography to assess uniformity of each specimen before submitted for FTIR and CA. RESULTS: Overall, the results of CA did not match with the FTIR results in 56 % of the cases. In 16 % of the cases CA missed the major stone component and in 40 % the minor stone component. 37 of the 60 specimens contained CaOx as major component by FTIR, and CA reported major CaOx in 47/60, resulting in high sensitivity, but very poor specificity. CA was relatively accurate for UA and cystine. CA missed struvite and calcium phosphate as a major component in all cases. In mixed stones the sensitivity of CA for the minor component was poor, generally less than 50 %. CONCLUSIONS: Urinary stone analysis using CA provides only limited data that should be interpreted carefully. Urinary stone analysis using CA is likely to result in clinically significant errors in its assessment of stone composition. Although the monetary costs of CA are relatively modest, this method does not provide the level of analytical specificity required for proper management of patients with metabolic stones

Legionella DotM structure reveals a role in effector recruiting to the Type 4B secretion system

Legionella pneumophila, a causative agent of pneumonia, utilizes the Type 4B secretion (T4BS) system to translocate over 300 effectors into the host cell during infection. T4BS systems are encoded by a large gene cluster termed dot/icm, three components of which, DotL, DotM, and DotN, form the “coupling complex”, which serves as a platform for recruitment of effector proteins. One class of effectors includes proteins containing Glu-rich/E-block sequences at their C terminus. However, the protein or region of the coupling complex mediating recruitment of such effectors is unknown. Here we present the crystal structure of DotM. This all alpha-helical structure exhibits patches of positively charged residues. We show that these regions form binding sites for acidic Glu-rich peptides and that mutants targeting these patches are defective in vivo in the translocation of acidic Glu-rich motif-containing effectors. We conclude that DotM forms the interacting surface for recruitment of acidic Glu-rich motif-containing Legionella effectors

Mechanism of effector capture and delivery by the type IV secretion system from Legionella pneumophila

Legionella pneumophila is a bacterial pathogen that utilises a Type IV secretion (T4S) system to inject effector proteins into human macrophages. Essential to the recruitment and delivery of effectors to the T4S machinery is the membrane-embedded T4 coupling complex (T4CC). Here, we purify an intact T4CC from the Legionella membrane. It contains the DotL ATPase, the DotM and DotN proteins, the chaperone module IcmSW, and two previously uncharacterised proteins, DotY and DotZ. The atomic resolution structure reveals a DotLMNYZ hetero-pentameric core from which the flexible IcmSW module protrudes. Six of these hetero-pentameric complexes may assemble into a 1.6-MDa hexameric nanomachine, forming an inner membrane channel for effectors to pass through. Analysis of multiple cryo EM maps, further modelling and mutagenesis provide working models for the mechanism for binding and delivery of two essential classes of Legionella effectors, depending on IcmSW or DotM, respectively

Linkage of murine (T,G)-A- -L-specific idiotypic determinants to the heavy chain constant region allotypic markers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46735/1/251_2005_Article_BF01567784.pd

Specificity and crossreactivity of idiotypes of murine antibodies induced by poly(Tyr,Glu)-poly(DLAla)-poly(Lys) and poly(Phe,Glu)-poly(DLAla)-poly(Lys)

Antibodies elicited against the two synthetic polypeptides, poly(Tyr,Glu)-poly(DLAla)-poly(Lys) [(T,G)-A-L] and poly(Phe,Glu)-poly(DLAla)-poly(Lys) [(Phe,G)-A-L], are crossreactive although the humoral responses to these immunogens are under different genetic controls. The fine specificity of the antibodies elicited by the two polypeptides was studied in the present work. Antisera against (Phe,G)-A-L bind both (125)I-labeled (T,G)-A-L and iodinated modified (Phe,G)-A-L. However, while the binding to (T,G)-A-L could be inhibited completely with the two antigens, the binding to (Phe,G)-A-L was inhibited completely with (Phe,G)-A-L and only partially with (T,G)-A-L. The binding of (125)I-labeled (T,G)-A-L to antisera against (T,G)-A-L was inhibted more efficiently by the homologous antigen than by (Phe,G)-A-L although both antigens completely inhibited the binding. (T,G)-A-L specific antibodies were purified on (T,G)-A-L immunoadsorbents from antisera of high and low responder mice to (T,G)-A-L immunized with (Phe,G)-A-L. (Phe,G)-A-L specific antibodies that did not bind (T,G)-A-L were isolated from the effluent of these columns. By use of anti-idiotypic antibodies of guinea pig against C3H.SW antibodies to (T,G)-A-L it was shown that (T,G)-A-L specific antibodies isolated from antisera against (Phe,G)-A-L of C3H.SW and C3H/DiSn mice possess part of the idiotypic determinants existing on antibodies of C3H.SW obtained by immunization with (T,G)-A-L. In contrast, antibodies to (Phe,G)-A-L that did not bind (T,G)-A-L did not share idiotypic determinants with C3H.SW antibody molecules against (T,G)-A-L. These results suggest that the B cell repertoire expressed by high and low responders to (T,G)-A-L after immunization with (Phe,G)-A-L is similar and represents only part of that of high responders immunized with (T,G)-A-L

Corneal autograft patches for covering exposed transscleral sutures

This article details the authors' experience with a relatively unknown technique for covering exposed ends of transscleral sutures. During combined transscleral suturing of a posterior chamber intraocular lens (PC IOL) with a penetrating keratoplasty, buttons from the excised recipient cornea are sutured with 10-0 nylon over the protruding suture ends. This technique has been used successfully in four cases

Herpes simplex virus keratitis after laser in situ keratomileusis

PURPOSE: To report two cases of herpes simplex virus (HSV) keratitis after laser in situ keratomileusis (LASIK). METHODS: Interventional small case series. Two patients underwent uneventful LASIK. History of herpes labialis in one patient and herpetic eye disease >10 years prior to intervention in the other patient was reported. Both patients developed stromal herpetic keratitis 6 weeks and 2 years after the procedure, respectively. RESULTS: Treatment consisting of topical steroid drops and topical and systemic antiviral therapy was administered. Recurrences of the herpetic keratitis were seen after tapering of the topical steroids; four and three recurrences were observed, respectively. Final visual acuity was >6/9 in both cases. CONCLUSIONS: Herpetic keratitis after LASIK is an uncommon, possibly under-reported, entity. Even patients without history of herpetic eye disease can present with this complication. Oral antiviral prophylaxis may be appropriate when performing LASIK on patients with a history of ocular or systemic HSV infection

Videokeratography findings in children with vernal keratoconjunctivitis versus those of healthy children

Purpose: To determine videokeratographic topography of eyes with vernal keratoconjunctivitis (VKC) and to assess whether the severity of the VKC is related to the presence of changes compatible with keratoconus. Participants: Seventy-six persons aged 6 to 21 years: 40 patients with VKC and 36 healthy controls. Design: A comparative, observational case series. Methods: We examined 76 persons, of whom 40 were patients with VKC and 36 were control subjects, and compared the outcomes of videokeratography (VKG) patterns (EyeSys Laboratories, Houston, TX), numerical corneal indices, and spherical equivalent refraction. Main Outcome Measures: Corneal topographic patterns, corneal numeric indices, and corneal mirror imagery. Results: We found many more abnormal patterns on VKG among the VKC patients than expected when compared with 'normal' eyes (P = 0.02 for the right eye and P = 0.001 for the left eye). Videokeratography allowed us to define a subgroup of patients with infraclinical keratoconus. A trend of superior corneal steepening ('superior keratoconus') was also found. Conclusions: Vernal keratoconjunctivitis patients have more abnormal corneal topographic patterns than non VKC controls. Videokeratography may help decide how to follow-up and treat a presumed self-limiting disease