A Comparative, Prospective and Randomized Evaluation of Roux-en-Y Gastric Bypass With and Without the Silastic Ring: A 2-Year Follow Up Preliminary Report on Weight Loss and Quality of Life.

BACKGROUND: Currently, Roux-en-Y gastric bypass (RYGB) is one of the most widely used bariatric surgeries. Banding the pouch forms a banded gastric bypass operation, an accepted and frequently used variant. Placing a silastic ring around the pouch to band the gastric bypass operation increases the restriction mechanism. However, the ubiquitous use of the banded gastric bypass remains controversial. One of the controversies is the effect of the silastic ring on patients' perception of their well being after surgery because of the frequency of vomiting. A prospective, blindly randomized, comparative trial was undertaken to resolve this controversy. METHOD: Four hundred subjects scheduled for gastric bypass surgery were randomized into two arms of the trial, 200 with a silastic ring (WR) and 200 without (NR). After 2-year follow-up, the variables associated with the scores of Bariatric Analysis and Reporting Outcome System (BAROS) were analyzed. RESULTS: The initial median weight (125 kg), BMI (47), and age (36 years) were the same in both the NR and WR groups. The median excess weight loss, weight regain, and incidence of vomiting were 71, 10.5, and 7.75%, respectively, in the NR group vs. 75.4 and 1.1, and 24.4% in the WR group. The mean QOL score was 79% in the NR group vs. 80% in the WR group. CONCLUSION: After 2-year follow-up, silastic ring placement in the RYGB resulted in greater weight loss and weight stability and a threefold greater incidence of vomiting. There was no difference in the scores in the quality of life analysis.

Delivery of Apical Mesenchymal Stem Cells into Root Canals of Mature Teeth.

Regenerative endodontic procedures are stem cell-based treatments for immature teeth with pulp necrosis. The translation of regenerative endodontic procedures into treating mature teeth depends, among other factors, on the availability and delivery of mesenchymal stem cells (MSCs) into the root canal system. The aim of this clinical study was to evaluate whether evoked bleeding from the periapical tissues elicits the influx of MSCs into the root canal system in mature teeth with apical lesions. Participants included in this study (N = 20) were referred for endodontic treatment of mature teeth with apical lesions. Following chemomechanical debridement, intracanal bleeding from the periapical tissues was achieved, and intracanal blood samples were collected. A positive blood aspirate was also collected in the cartridges during local anesthesia. Total RNA was isolated and used as a template in quantitative reverse transcription polymerase chain reactions using MSC-specific arrays. Data were analyzed with the Wilcoxon signed-rank test, and correlation between gene expression and sex or age was tested with Spearman's rank correlation coefficient test. In addition, MSCs were isolated from an intracanal bleeding sample and subjected to flow cytometry and quantitative osteogenesis assay. Last, the presence and distribution of MSCs within periradicular lesions were evaluated with immunohistochemistry (n = 4). The MSC markers CD73, CD90, CD105, and CD146 were significantly upregulated, with median fold change values of 2.9, 31.7, 4.6, and 6.8, respectively. Conversely, the negative marker for MSCs, CD45, was significantly downregulated (median, -2.7). There was no correlation with age, sex, tooth type, or treatment for any of the evaluated genes. Isolated intracanal cells coexpressed MSC markers and demonstrated robust mineralizing differentiation potential. Finally, immunohistochemical analysis revealed that MSCs were found compartmentalized mainly within vasculature structures located in periapical lesions. Collectively, findings indicate that the evoked-bleeding technique delivers MSCs into the root canal system in mature teeth with apical lesions.

Nerve growth factor receptor (p75)-immunoreactivity in the normal adult feline trigeminal system and following retrogasserian rhizotomy.

The 75 kDa protein nerve growth factor receptor [NGFr(p75)] is a neurotrophin receptor that is able to bind different members of the neurotrophin family of molecules implicated in affecting neuronal survival. Here we describe the light microscopic distribution of NGFr(p75)-immunoreactivity (IR) within the feline trigeminal brainstem sensory nuclear complex and trigeminal ganglion of normal adult subjects and in subjects 10 and 30 days following retrogasserian rhizotomy. Within the trigeminal ganglion of normal subjects, numerous fibers and most of the neuronal cell bodies showed NGFr(p75)-IR that varied in intensity, while cells and fibers with NGFr(p75)-IR were less numerous within the mesencephalic trigeminal nucleus. Within the main sensory and spinal trigeminal nuclei, NGFr(p75)-IR formed a reproducible pattern that varied between the different subnuclei. The NGFr(p75)-IR consisted both of dense pockets and a low level NGFr(p75)-IR that was selective to the trigeminal neuropil. Following rhizotomy, most of the NGFr(p75)-IR was lost from the main sensory and spinal trigeminal nuclei, except in regions where the upper cervical roots and cranial nerves VII, IX, and X project. In contrast, examination of the central root that was still attached to the trigeminal ganglion showed increased NGFr(p75)-IR in fibers and supporting cells, as did the motor root within the peripheral mandibular division. These results indicate that the majority of the NGFr(p75)-IR within the main sensory and spinal trigeminal nuclei originates from primary trigeminal afferents and that retrogasserian rhizotomy leads to an up-regulation of NGFr(p75)-IR in the part of the central root that is contiguous with the ganglion.

Enhanced ultrastructural visualization of the horseradish peroxidase-tetramethylbenzidine reaction product.

Ultrastructural visualization of the horseradish peroxidase-tetramethylbenzidine (HRP-TMB) reaction product within trigeminal ganglion cells and brain stem axons and terminals following HRP injections into the pulpal chambers of cat teeth is enhanced by utilization of a modified osmication procedure that converts the reaction product to a markedly stable and electron-dense form. The results following the use of the modified osmication procedure (pH 5.0 phosphate buffer at 20 degrees C for 12 hours) are compared to results obtained by following Carson's osmication protocol (Carson KA, Mesulam M-M: J Histochem Cytochem 30:425, 1982; Carson KA, Mesulam M-M: In Tracing Neural Connections with Horseradish Peroxidase. Edited by M-M Mesulam. J Wiley, Chichester, England, 1982, p 153-184) (pH 6.0 phosphate buffer at 45 degrees C for 45 min). The results suggest that the conversion of the HRP-TMB reaction product to an electron-dense form during osmication is intimately associated with the pH of the phosphate buffer and the total time of osmication.

Toxic ricin demonstrates a dual dental projection.

Toxic ricin was used to study the central distribution of dental afferents in the cat. Following intrapulpal ricin injections ganglion cell degeneration is seen in the II and III ganglion divisions. Central argyrophilic degeneration occurs in the dorsal portion of all ipsilateral trigeminal nuclei. Ventral degeneration is seen in the pars interpolaris and pars caudalis. No contralateral degeneration was observed. The results are discussed with regard to previous studies of the central location of dental afferents.

The effect of experimental anesthetization of the temporomandibular joint superior cavity on bite force discrimination.

The purpose of this study was to determine whether bilateral experimental sensory impairment of the temporomandibular joints (TMJs), as induced by injecting 1.5 ml of two percent mepivacaine into the superior cavity of the TMJs would alter the subject's ability to discriminate among differences in their bite force. Assessment of bite force was measured isometrically, using the strain gauge scale, and isotonically, using the mechanical swing beam scale. Resistance forces of 500 and 1000 gms were selected as standards. For each task, subjects were given a series of paired resistance settings, one at a time, the first of each pair being the standard resistance and the second being a comparator resistance of some greater amount. Subjects reported whether biting against the comparator resistance was equal to, greater than, or less than the standard resistance. This procedure of paired comparisons was continued until the subject's threshold of discrimination (difference limen value) between two biting forces was established. The results revealed that the subject's ability to discriminate differences in their bite force, either isometrically or isotonically, was not significantly (p greater than 0.05) affected following anesthetization of the superior cavity of the TMJs. These findings suggest that the sensory receptors within the TMJ capsules are not significantly involved in the detection of forces that play a role in monitoring biting force.

Pulpitis increases the proportion of atypical nodes of Ranvier in human dental pulp axons without a change in Nav1.6 sodium channel expression.

Studies show a change in sodium channel (NaCh) expression after inflammatory lesions, and this change is implicated in the generation of pain states. We are using the extracted human tooth to study NaCh expression and here examine the expression of the major NaCh isoform located at nodes of Ranvier, Na(v)1.6, in normal and painful samples. Pulpal sections were double-labeled with human-specific Na(v)1.6 antibody and caspr antibody (paranodal protein to identify nodes). Confocal microscopy was used to obtain a z-series of optically-sectioned images of axon bundles surrounded by inflammatory cells in painful samples and of similar regions within the coronal pulp of normal samples. Nodes contained within these images were classified as typical or atypical as based on caspr staining relationships, and NIH ImageJ software was used to quantify the size and immunofluorescence staining intensity of Na(v)1.6 accumulations at these nodal sites. Results show no significant difference in the size or immunofluorescence staining intensity of Na(v)1.6 nodal accumulations located at either typical or atypical nodal sites (heminodes and split nodes) within axons in normal samples when compared to painful samples (n=9/each group). In contrast, there was a highly significant decrease in the proportion of typical nodal sites and an increase in atypical nodal sites in painful samples when compared to normal samples. The unchanged expression of Na(v)1.6 contrasts to our previous finding that showed an increased expression of Na(v)1.7 at both typical and atypical nodal sites within painful samples. Together, these findings suggest there is not a simple replacement of one isoform with another, but rather an increased co-expression of multiple isoforms at both intact and remodeling/demyelinating (atypical) nodal sites within the painful dental pulp. The resultant heterogeneous population of isoforms may produce unique axonal excitability properties that could contribute to spontaneous pain sensations that are common in toothache.

Central representation of dental structures in the kitten, including projections to the mesencephalic trigeminal nucleus.

Horseradish peroxidase (HRP) was injected into either a single maxillary or a single mandibular primary (deciduous) cuspid tooth of 8- to 10-week-old kittens. The large apex of the primary cuspid allowed for some leakage of the HRP from the pulpal chamber to the periodontal ligament (PDL). Thus, the injection procedure resulted in the application of HRP to the PDL as well as to the pulpal tissues. The transganglionic transport of HRP resulted in discrete terminal fields within the spinal trigeminal nucleus (STN) and the main sensory nucleus (MSN). These projections were clearly somatotopically organized within the STN, but less so within MSN. Within pars oralis (PO) and pars interpolaris (PI), mandibular cuspid dental structures (MdCDS) were represented in a dorsal position relative to the maxillary cuspid dental structures (MxCDS), whereas within pars caudalis (PC) and the adjacent reticular formation the somatotopic representation was not dorsoventral, but rather mediolateral, with the MdCDS represented more medially than the MxCDS. Areas of overlap between MxCDS and MdCDS were found within MSN and to a lesser degree within the superficial laminae of PC. In addition, the fiber pathway leading to labeled somata in the mesencephalic trigeminal (Mes V) nucleus was clearly identified. The majority of the fibers traced to the Mes V nucleus exited the spinal trigeminal tract at the level of the transition from PO to the MSN and traversed the nuclear region in a position dorsal to and separate from the trigeminal motor tract. As in STN, fibers within the caudal Mes V tract appeared to be somatotopically organized, with the fibers from the MdCDS generally more dorsal than the ones from the MxCDS. Labeled fibers, some with terminal arbors, were also identified in close association with the trigeminal motor tract. The findings show a complex pattern of central representation in the immature feline central nervous system for deciduous dental structures.

Light- and electron-microscopic localization of primary dental afferents to medullary dorsal horn (pars caudalis).

Light-microscopic (LM) and ultrastructural (electron-microscopic, or EM) identification of primary dental afferents to medullary dorsal horn (MDH) was demonstrated in the cat following injections of horseradish peroxidase (HRP) into pulpal chambers of unilateral maxillary and mandibular posterior teeth, including the cuspids. Use of a new osmication protocol improved and simplified the EM localization of reaction product within the brain stem terminals. LM examination showed that the projection pattern varied between the different levels of MDH. At caudal levels, the labeling was primarily confined to a narrow band consisting of a dense projection to the dorsomedial portion of laminae I and superficial II and a less intense projection to lamina V. The pattern to rostral levels became increasingly more dense and extensive within these same laminae. LM examination of the tooth apex region showed that a limited spread to the periodontal ligament occurred in some cases. EM investigation of the ipsilateral MDH demonstrated reaction product in terminals with synaptic vesicles that are presynaptic to small and medium-sized dendrites. Labeled axonal endings in close association with cell bodies were also observed. No labeled structures were identified in the contralateral MDH. Some of the reaction product found with EM was below the LM limit of resolution, and thus ultrastructural investigation is necessary for a complete analysis of any pathway when using HRP.

Ultrastructure of degenerative changes following ricin application to feline dental pulps.

The ultrastructure of degenerative changes within the ipsilateral trigeminal ganglion, and partes caudalis and interpolaris of the spinal trigeminal nucleus in the cat is described following the application of the potent toxin ricin to the tooth pulps of unilateral maxillary and mandibular posterior teeth, including the cuspids. Survival times ranged from 6 to 10 days. Typical changes identified within the ipsilateral trigeminal ganglion included myelin fragmentation and 'compartmentalization' of the axoplasm of medium-sized myelinated axons, while small myelinated and unmyelinated axons underwent a more variable response ranging from electron-lucent to electron-dense changes. The affected cell body was characterized by the presence of swollen, electron-lucent mitochondria, a reduction of cytoplasmic ribosomes and a filamentous hyperplasia. Other changes often included an eccentric nucleus and satellite cell proliferation. Degenerative changes often occurred in isolated elements surrounded by normal profiles, suggesting specificity of ricin within the trigeminal ganglion. Changes within brainstem axons showed both an electron-dense and a lucent, fragmenting type of axonal alteration. Terminal changes ranged from electron-dense to lucent and also included filamentous hyperplasia and 'hyperglycogenesis'. The altered axonal knobs contained round synaptic vesicles that were presynaptic to dendritic profiles and postsynaptic to terminals containing flattened synaptic vesicles. The above brainstem alterations were identified specifically in the following areas: ventrolateral, medial and dorsomedial pars interpolaris; the ventrolateral and mid-dorsal to dorsomedial areas of the marginalis and outer substantia gelatinosa layers of pars caudalis; and in ventral pockets corresponding to lamina V of the medullary dorsal horn. Dense alterations within terminals containing flattened synaptic vesicles that are typically presynaptic to primary afferents in these areas were rare findings, but along with vacuolization of dendritic profiles suggest a trans-synaptic effect possibly due to the exocytosis of ricin. The results are discussed in relation to different reports of dental projections and with regards to patterns of transganglionic degeneration.

Localization of nerve growth factor receptor immunoreactivity in the trigeminal nucleus of kittens.

A monoclonal antibody raised against the human nerve growth factor receptor (NGFr) was used to map the distribution of NGFr-immunoreactivity (IR) in the trigeminal nuclear complex of 8- to 10-week-old, immature felines. Somata and fibers show NGFr-IR within the trigeminal ganglion and the mesencephalic trigeminal nucleus. NGFr-IR is also found in fibers within the trigeminal root entry zone, the spinal trigeminal tract, and in fibers and terminals within all the central trigeminal sensory nuclei. The NGFr-IR found within the trigeminal sensory nuclei typically occurs in circumscribed zones that vary in position for the different subnuclei. NGFr-IR is found in the dorsomedial and ventrolateral subdivisions of the main sensory nucleus, in the dorsomedial and occasionally in ventral positions within pars oralis, in dorsal and ventral regions within pars interpolaris, and primarily in outer lamina II with fibers that project to lamina V within pars caudalis/medullary dorsal horn. These results show some overlap with the central distribution of trigeminal primary afferent nociceptive fibers such as those found from the tooth pulp and overlap with the central distribution of such peptides as calcitonin gene-related peptide and substance P, but NGFr-IR is more restricted. Thus, it appears that NGFr-IR is associated with the endings of primary afferent fibers in the brain stem, and that these fibers may represent a certain subclass of primary afferent nociceptors. It is speculated that fibers showing NGFr-IR may have the ability to alter their response to peripheral deafferentation when compared to fibers lacking NGFr-IR.