Reflections on the Michigan splint and other intraocclusal devices

It seems obvious in retrospect that the treatment of disorders by interocclusal devices followed two paths: stabilization splints and functional orthopedic appliances. The dividing line between them is not always clear. Both have some function related to the position of the mandible. They may not differ significantly in their control of occlusal stability (e.g., telescoping devices anchored to stabilization splints). The stabilization splint, as well as other conservative measures, will play an increasing role in accepted therapy for TMD. The use of anterior repositioning devices for TMD, including MPD syndrome, will decrease. Research may provide answers that allow them to be used more specifically and predictably. Perhaps there will be but little change in their use where there is an association of TMD and Class II malocclusion. There will be an increase in the use of interocclusal devices for the treatment of snoring and obstructive apnea. Some additional directions seem to have emerged in the late 1980s and early 1990s: In the absence of pain and significant debilitation, treatment for TMD, if any, is to be reversible. Prevention or aggravation of TMD should be practiced to the extent possible during dental procedures. One long-term, well-designed, prospective study indicated that the incidence and severity of TMD could be reduced by appropriate occlusal adjustment. There is a small, but nevertheless important minority of patients with TMD who progress to persistent pain and/or dysfunction. Initial management of the vast majority of patents with TMD should be use of noninvasive reversible therapies. Surgery is indicated in only a relatively small percentage of cases of TMD. Research on interocclusal devices should not terminate simply because they are in part dental devices (i.e., biomechanical forms of treatment). The diagnosis and treatment of TMD has been called a dilemma, especially for those patients with chronic pain for whom no treatment has been effective. However, it would be ill-advised to abandon what treatment is already known to be effective by allowing those few but psychosocially important patients with chronic pain to determine what should be done for the vast majority of patients with TMD: reversible forms of treatment, including physiotherapy, pharmacologicals, and the stabilization occlusal bite plane splint.     

Some characteristics of a cellular receptor for virulent infectious bursal disease virus by using flow cytometry

A flow cytometric virus binding assay that directly visualizes the binding of infectious bursal disease virus (IBDV) to its target cells was established. The chicken B lymphoblastoid cell line, LSCC-BK3, which is permissive for IBDV infection, bound high levels of the virus. Another B lymphoblastoid cell line, LSCC-1104-B1, bound low levels of the virus, although it was nonpermissive. No virus binding was detected in nonpermissive T lymphoblastoid cell lines. In the binding assay to heterogeneous cell populations of chicken lymphocytes, IBDV (a highly virulent OKYM strain) bound to 94% cells in the lymphocytes prepared from the bursa of Fabricius, 37% cells in those prepared from the spleen, 3% cells in those prepared from the thymus, and 21% cells in those prepared from the blood. Most of the cells, which bound the virus, were surface immunoglobulin M (SIgM)-positive, but a small number of them were SIgM-negative. Additionally, the binding of IBDV to the LSCC-BK3 cells was affected by treatment of the cells with proteases and N-glycosylation inhibitors. These findings may indicate that the IBDV host range is mainly controlled by the presence of a virus receptor composed of N-glycosylated protein associated with the subtle differentiation stage of B-lymphocytes represented mostly by SIgM-bearing cells.     

Outcome criteria in strabismus surgery

PURPOSE: The authors describe the first case of delayed antimetabolite-related corneal epithelial toxicity after trabeculectomy and its successful treatment with limbal stem cell transplantation. METHODS: A 73-year-old woman underwent trabeculectomy with intraoperative mitomycin C. After surgery she received six 5-mg injections of subconjunctival 5-fluorouracil (5-FU) adjacent to the bleb. RESULTS: The patient had a functioning trabeculectomy and clear cornea until 30 months after surgery, at which time she developed a nonhealing superior corneal epithelial defect. After 4 months of conservative medical management, an autologous limbal stem cell transplantation was performed. The epithelial defect resolved completely within 1 week of limbal stem cell transplantation. CONCLUSIONS: Delayed corneal epithelial toxicity may be a late complication of antimetabolite-augmented trabeculectomy.     

Reevaluation of Cl-/HCO3- exchange in cultured bovine corneal endothelial cells

PURPOSE: To determine the apical versus basolateral polarity of the putative anion exchanger in cultured bovine corneal endothelial cells (BCECs) and to examine the influence of Cl--dependent membrane potential (Em) changes on HCO3- transport. METHODS: BCECs grown on permeable supports were used for independent perfusion of apical and basolateral surfaces. Intracellular pH (pHi) was measured using the fluorescent dye BCECF. Relative changes in Em were measured using the fluorescent dye bis-oxonol. Western blot analysis was used to detect immunoreactivity against the anion exchanger (AE1 or AE2). RESULTS: Cl- removal from apical and basolateral surfaces produced cellular alkalinization (apical side, 0.07 pH units; basolateral side, 0.06 pH units; both sides, 0.20 pH units). Application of 100 microM H2-4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonic acid (DIDS), an anion exchange inhibitor, on the apical side produced an alkalinization (0.02 pH units) followed by acidification (-0.05 pH units), whereas basolateral H2DIDS caused a substantial acidification (-0.16 pH units). In the absence of Na+, Cl- removal from the apical side caused a transient alkalinization (0.03 pH units) followed by a return to baseline; Cl- removal from the basolateral side caused a small (-0.03) acidification. In Na+-free Ringer, apical H2DIDS produced a transient alkalinization (0.02 pH units), whereas basolateral exposure had no effect. 5-Nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), N-phenylanthranilic acid (DPC), and niflumic acid (50-200 microM), known Cl- channel blockers, produced cellular acidification in control Ringer. Niflumic acid hyperpolarized Em and inhibited depolarization after Cl- removal. Western blot analysis failed to detect AE2 expression in cultured BCECs. However, fresh BCECs produced a trace response. CONCLUSIONS: Physiological activity of an apical anion exchanger is weak in cultured BCECs. Cultured BCECs have significant Cl- conductance. Thus, cellular alkalinization after Cl- removal is caused primarily by depolarization of Em, which drives HCO3- influx through the basolateral electrogenic Na+:nHCO3- cotransporter. In contrast with cultured BCECs, AE2 may be present in fresh cells.     

Fluctuations in visual neglect after stroke?

Clinical experience suggests that the visual neglect in stroke patients fluctuates over short periods of time. This fluctuation has been variously attributed to fatigue, time of day, previous activities, patient learning and compensation. Such fluctuations have clinical implications for the assessment and rehabilitation of visual neglect but do date no formal study has evaluated the extent of such fluctuation over the course of a day. Twenty-two patients with an acute stroke and 19 patients with convalescent stroke were examined for visual neglect twice on the same day using the Visual Neglect Recovery Index (VNRI), a valid and sensitive measure of the severity of neglect, which could be used to select acute patients for trials of treatment of neglect. The inter-test reliability was extremely high. In contrast to past clinical accounts most patients failed to show significant fluctuation. Although preliminary, this finding suggests that a single assessment of visual neglect, using the VNRI, could help select patients for treatment trials.     

The simplified two-pipette technique is more efficient than the conventional three-pipette method for blastomere biopsy in human embryos

Kell and Kx are two quantitatively minor proteins from the human erythrocyte membrane which carry blood groups antigens and are thought to be a metalloprotease and a membrane transporter, respectively. In the red cell membrane, these proteins form a complex stabilized by disulfide bond(s). Phosphorylation status of these proteins was studied, in the presence or absence of effectors of several kinases, either on intact cells incubated with [32P]-orthophosphate or on ghosts incubated with [gamma-32P]ATP. Purification of Kell-Kx complex, by immunochromatography on an immobilized human monoclonal antibody of Kell blood group specificity allowed to establish that (i) neither protein is phosphorylated on tyrosine; (ii) the Kell protein is a putative substrate for Casein Kinase II (CKII) and Casein Kinase I (CKI) but not for protein kinase C (PKC), whereas Kx protein is phosphorylated by CKII and PKC but not by CKI; (iii) Protein Kinase A neither phosphorylates the Kell nor the Kx proteins.     

Insulin-like growth factor binding protein-1 at mouse neuromuscular synapses

The insulin-like growth factor (IGF) signaling system includes the growth factors and their cell surface receptors, along with circulating IGF binding proteins (IGFBPs) that may alter and modulate the action of these neurotrophic hormones. These IGFBPs, along with IGFs and receptors, have been detected in various tissues including the brain. In this study, using polyclonal antibody to human IGFBP-1 or bovine IGFBP-2, we found that mouse muscle extracts contain similar-sized proteins that cross-react with these antibodies on Western immunoblots. After establishing that these antibodies reacted with the homologous murine IGFBPs, we performed immunocytochemistry to demonstrate the localization of IGFBP-1 at the neuromuscular junction, a model nicotinic, cholinergic synapse, as well as within intramuscular nerves. IGFBP-2, a distinct macromolecule, is present on the surface of muscle fibers and is not present within synapses or nerves.     

GaInP/GaAs HBTs for high-speed integrated circuit applications

The use of GaInP/GaAs heterojunction bipolar transistors (HBTs) for integrated circuit applications is demonstrated. The discrete devices fabricated showed excellent DC characteristics with low V_ce offset voltage and very low temperature sensitivity of the current gain. For a non-self-aligned device with a 3-μm×1.4-μm emitter area, f_T was extrapolated to 45 GHz and f_max was extrapolated to 70 GHz. The measured 1/f noise level was 20 dB better than that of AlGaAs HBTs and comparable to that of low-noise silicon bipolar junction transistors, and the noise bump (Lorentzian component) was not observed. The fabricated gain block circuits showed 8.5 dB gain with a 3-dB bandwidth of 12 GHz, and static frequency dividers (divide by 4) were operable up to 8 GHz