Subdental synchondrosis and anatomy of the axis in aging: a histomorphometric study on 30 autopsy cases

During skeletal development the two ossification centers of the odontoid process are separated from the corpus of the axis by a subdental synchondrosis. This synchondrosis is thought to close and disappear spontaneously in adolescence although this has never been studied in detail. The basis of the dens is of clinical relevance as type II dens fractures are located here. To characterize the morphological architecture of the axis with particular attention to the subdental synchondrosis, the complete axis was harvested from thirty age-matched and gender-matched patients of the three different age groups at autopsy. The subdental synchondrosis and the bone structure of the dens, the basis of the dens and the body of C2 were analyzed by radiography, histology and quantitative histomorphometry. At the macroscopic level the persistency of the subdental synchondrosis in the adult cervical spine was detected in 87% (26 of 30) of the specimens. Histomorphometry revealed a residual disc blastema with an average size of 25.8% of the sagittal depth of the basis of the dens at this level. Bony integration of the synchondrosis was poor throughout all ages. Histologically a cartilaginous matrix composition of the subdental synchondrosis persisted throughout all groups. The trabecular microarchitecture demonstrated a significant reduction of bone volume and trabecular number as well as an increased trabecular separation within the basis of the dens as compared to the corpus or the dens of C2. This histomorphometric data regarding a poor integration of the synchondrosis into the trabecular network and the reduced bone mass within the basis of the dens might offer a previously underestimated explanation for the occurrence of type II dens fractures and their association with pseudoarthrosis, respectively.Matthias Gebauer and Christian Lohse contributed equally to this study and therefore share first authorship.     

The REPAIR-AMI and ASTAMI trials: cell isolation procedures: reply

It obviously escaped the notion of Egeland and Brinchman thatthe protocols additionally differ with regard to the washingsteps and buffer components used in the     

Aging pathways for organophosphate-inhibited human butyrylcholinesterase, including novel pathways for isomalathion, resolved by mass spectrometry.

Some organophosphorus compounds are toxic because they inhibit acetylcholinesterase (AChE) by phosphylation of the active site serine, forming a stable conjugate: Ser-O-P(O)-(Y)-(XR) (where X can be O, N, or S and Y can be methyl, OR, or SR). The inhibited enzyme can undergo an aging process, during which the X-R moiety is dealkylated by breaking either the P-X or the X-R bond depending on the specific compound, leading to a nonreactivatable enzyme. Aging mechanisms have been studied primarily using AChE. However, some recent studies have indicated that organophosphate-inhibited butyrylcholinesterase (BChE) may age through an alternative pathway. Our work utilized matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry to study the aging mechanism of human BChE inhibited by dichlorvos, echothiophate, diisopropylfluorophosphate (DFP), isomalathion, soman, sarin, cyclohexyl sarin, VX, and VR. Inhibited BChE was aged in the presence of H2O18 to allow incorporation of (18)O, if cleavage was at the P-X bond. Tryptic-peptide organophosphate conjugates were identified through peptide mass mapping. Our results showed no aging of VX- and VR-treated BChE at 25 degrees C, pH 7.0. However, BChE inhibited by dichlorvos, echothiophate, DFP, soman, sarin, and cyclohexyl sarin aged exclusively through O-C bond cleavage, i.e., the classical X-R scission pathway. In contrast, isomalathion aged through both X-R and P-X pathways; the main aged product resulted from P-S bond cleavage and a minor product resulted from O-C and/or S-C bond cleavage.     

Granulomatous jellyfish dermatitis

The induction of a granulomatous inflammation by jellyfish toxins is rare. More typically, acute toxic and urticarial reactions are seen. An 11-year-old boy developed a striated urticarial erythema on the left cheek after contact with a gelatinous mass while swimming in the sea in Croatia. After initial erosion, a striated induration developed in the area of contact. Histological examination revealed a granulomatous inflammation with some eosinophils. While topical steroid-based antiinflammatory and antibacterial therapy over several weeks was not effective, topical therapy with tacrolimus 0.1% for two two-week treatment periods led to healing of the skin changes with a slight scar. There was no clinical recurrence after 5 month of follow-up.     

Pharmacokinetics and haemodynamic effects of ISDN following different dosage forms and routes of administration

The pharmacokinetics and haemodynamic effects of isosorbide dinitrate (ISDN) have been investigated following administration of single doses as a sublingual (SL) spray (2.5 mg), sublingual tablet (5 mg) and peroral tablet (10 mg) in a randomised, placebo-controlled double-blind cross-over trial in 16 healthy volunteers.After the sublingual spray C_max was higher (39.0 ng·ml^-1) and t_max was shorter (3.9 min) than after the sublingual (22.8 ng·ml^-1 and 13.8 min) and peroral (16.9 ng·ml^-1 and 25.6 min) tablets. The AUC of ISDN did not differ following any of the three formulations (1031; 879; 997 ng·ml^-1·min, for the spray, SL tablet and PO-tablet, respectively). Mononitrate metabolites of ISDN (IS-2-MN and IS-5-MN) and total nitrates in plasma increased in proportion to the administered dose. This indicates that the fraction of the dose absorbed was the same for all the formulations but that the extent of first-pass metabolism increased in the order sublingual spray < sublingual tablet < peroral tablet. Thus, compared to the spray, the relative bioavailability of ISDN was 48% and 28% from the sublingual and peroral tablets, respectively.The haemodynamic effects were quantified using the a/b ratio of the finger pulse wave and the systolic blood pressure and heart rate under orthostatic conditions. For the a/b ratio of the finger pulse, the maximal effect was higher (e_max=130%) and the time to e_max (t_emax) shorter (16.6 min) after the spray than the sublingual tablet (84.4% and 25.5 min) or peroral tablet (90.2 and 31.3 min). The onset of effect was within 3, 5 and 7.5 min after the spray, sublingual and peroral tablets, respectively. A larger change in the orthostatically-induced decrease in systolic blood pressure and increase in heart rate was obtained following peroral than sublingual administration despite the similar plasma concentrations of ISDN. This probably reflects the larger amount of pharmacodynamically active mononitrate metabolites formed after oral dosing. The integrated effect following administration of 2.5 mg ISDN as spray was similar to that of a sublingual tablet of 5 mg.     

Implantation of posterior chamber lenses in eyes with phakodonesis and lens subluxation

Unilateral posterior chamber intraocular lens (IOL) implantation was performed after phacoemulsification or extracapsular cataract extraction in ten of 11 patients with phakodonesis or lens subluxation, which was bilateral in two cases. To facilitate placement of the IOL, the anterior capsule was opened with a YAG laser in nine patients. Intraoperative vitrectomy was performed in two patients, and posterior chamber IOL implantation was accomplished with fixation in the ciliary sulcus. Postoperative follow-up studies failed to demonstrate significant decentration or dislocation of the IOLs. Phakodonesis and lens subluxation are no longer considered absolute contraindications to implantation of posterior chamber IOLs.