Citations

OBJECTIVETo evaluate hearing outcomes and effects of stimulation rate on performance with the Nucleus Freedom cochlear implant (Cochlear Americas, Denver, CO).STUDY DESIGN AND SETTINGRandomized, controlled, prospective, single‐blind clinical study using single‐subject repeated measures (A‐B‐A‐B) design at 14 academic centers in the United States and Canada and comparison with outcomes of a prior device by the same manufacturer.PATIENTSSeventy‐one severely/profoundly hearing impaired adults.RESULTSSeventy‐one adult recipients were randomly programmed in two different sets of rate: ACE or higher rate ACE RE. Mean scores for Consonant Nucleus Consonant words is 57%, Hearing in Noise Test (HINT) sentences in quiet 78%, and HINT sentences in noise 64%. Sixty‐seven percent of subjects preferred slower rates of stimulation, and performance did not improve with higher rates of stimulation using this device.CONCLUSIONSSubjects performed well, and there was no advantage to higher stimulation rates with this device.SIGNIFICANCEHigher stimulation rates do not necessarily result in improved performance.

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection causes apoptosis of infected CD4 T cells as well as uninfected (bystander) CD4 and CD8 T cells. It remains unknown what signals cause infected cells to die. We demonstrate that HIV-1 protease specifically cleaves procaspase 8 to create a novel fragment termed casp8p41, which independently induces apoptosis. casp8p41 is specific to HIV-1 protease-induced death but not other caspase 8-dependent death stimuli. In HIV-1-infected patients, casp8p41 is detected only in CD4 + T cells, predominantly in the CD27 + memory subset, its presence increases with increasing viral load, and it colocalizes with both infected and apoptotic cells. These data indicate that casp8p41 independently induces apoptosis and is a specific product of HIV-1 protease which may contribute to death of HIV-1-infected cells.

Abstract A group of 500 patients with a presumptive diagnosis of primary hyperparathyroidism (HPT) was operated upon at the Mayo Clinic between September 1974 and May 1980 using a standardized operative strategy. Clinical profiles, biochemical data, operative findings and pathological changes are reviewed. Of the 500 patients, 461 (92·2 per cent) were cured after primary cervical exploration. One patient died during the postoperative period, 1 had a permanent unilateral vocal cord paralysis and 10 (2 per cent) had protracted hypoparathyroidism. Owing to the continuing controversy regarding the appropriate therapeutic management of asymptomatic, uncomplicated and mild (‘biochemical’) primary HPT, we further evaluated this surgical experience by comparing the results of operation in two groups of patients: those with (‘biochemical’) HPT (serum calcium < 11 mg/dl) and those with ‘non-biochemical’ HPT (symptomatic or complicated disease or serum calcium > 11 mg/dl). The cure rate in each patient group was greater than 90 per cent. A statistically significant increase in the incidence of negative cervical exploration (4 normal parathyroid glands identified and biopsied) was noted in the ‘biochemical’ group. However, parathyroid disease was found at operation in 92 per cent of these patients. We conclude that cervical exploration in all patients with primary HPT, including those with ‘biochemical’ disease only, is safe and that such an aggressive management policy is justified.

Abstract Although multiple hormones and cytokines regulate various aspects of osteoclast formation, the final two effectors are osteoprotegerin ligand (OPG-L)/osteoclast differentiation factor (ODF), a recently cloned member of the tumor necrosis factor superfamily, and macrophage colony–stimulating factor. OPG-L/ODF is produced by osteoblast lineage cells and exerts its biological effects through binding to its receptor, osteoclast differentiation and activation receptor (ODAR)/receptor activator of NF-κB (RANK), on osteoclast lineage cells, in either a soluble or a membrane-bound form, the latter of which requires cell-to-cell contact. Binding results in rapid differentiation of osteoclast precursors in bone marrow to mature osteoclasts and, at higher concentrations, in increased functional activity and reduced apoptosis of mature osteoclasts. The biological activity of OPG-L/ODF is neutralized by binding to osteoprotegerin (OPG)/osteoclastogenesis inhibitory factor (OCIF), a member of the TNF-receptor superfamily that also is secreted by osteoblast lineage cells. The biological importance of this system is underscored by the induction in mice of severe osteoporosis by targeted ablation of OPG/OCIF and by the induction of osteopetrosis by targeted ablation of OPG-L/ODF or overexpression of OPG/OCIF. Thus, osteoclast formation may be determined principally by the relative ratio of OPG-L/ODF to OPG/OCIF in the bone marrow microenvironment, and alterations in this ratio may be a major cause of bone loss in many metabolic disorders, including estrogen deficiency and glucocorticoid excess. That changes in but two downstream cytokines mediate the effects of large numbers of upstream hormones and cytokines suggests a regulatory mechanism for osteoclastogenesis of great efficiency and elegance.

OBJECTIVE:To assess the magnetic resonance imaging (MRI) safety of titanium middle ear prostheses at 3.0 tesla (T).STUDY DESIGN AND SETTING:Titanium middle ear prostheses from 3 commercial vendors were examined for magnetic field interactions at 3 T. Initially, ex vivo studies were performed to test for rotational motion and forward displacement (translational motion) of the prostheses in a static magnetic field. If movement was observed during this screening study, then the prosthesis was tested to determine the translational or rotational force acting upon the prosthesis. In addition to testing for prosthesis displacement, temperature changes of the prostheses were measured to assess for radiofrequency heating during imaging.RESULTS:Twenty‐one of the 24 titanium prostheses tested revealed no movement when tested in the 3 T static magnetic field. Three prostheses revealed minimal movement during the screening study. A translational force test (string test) was performed upon these 3 prostheses, and the measured angle of displacement was used to determine the force. This calculated force acting upon each prosthesis was essentially zero. Therefore, we conclude that the magnetic field interaction is negligible. A positive control with a ferromagnetic stainless steel prosthesis demonstrated obvious displacement during the screening study, as well as deflection of the prosthesis by 90° in the translational force test. Last, heating of the titanium prostheses did not occur in the 7 models tested.CONCLUSIONS:Middle ear prostheses made from titanium are safe, neither deflecting nor heating during magnetic resonance examinations conducted at 3 T. EBM rating: C‐1.

Abstract OBJECTIVE AND IMPORTANCE We report the case of a 29-year-old man with Gardner syndrome and an isolated, giant cerebellopontine angle craniopharyngioma. Our description of this patient is only the second case report of a craniopharyngioma arising primarily in the cerebellopontine angle. CLINICAL PRESENTATION The patient presented with a 1-year history of progressive neurological impairment and headache. On the basis of the patient's history of multiple dermal fibromas, a cranial osteoma, familial adenomatous polyposis (FAP), a total abdominal colectomy, and an adenoma of the ampulla of Vater, we diagnosed the patient's condition as Gardner syndrome. INTERVENTION Magnetic resonance imaging showed a large cerebellopontine angle tumor, which was removed through a suboccipital retromastoid craniotomy. The pathological features were those of an adamantinomatous craniopharyngioma. The patient has done well postoperatively and has no new neurological deficits. A careful retrospective review of the preoperative imaging shows that this tumor was located exclusively in the posterior fossa and was not an extension of a sellar, suprasellar, or clival craniopharyngioma. CONCLUSION We present the second reported case of FAP and craniopharyngioma. There is no known genetic link between FAP and craniopharyngioma. Now that the patient has manifested a primary tumor of the central nervous system with FAP, it is unclear whether he should be classified as having Turcot syndrome. For this patient, we recommended vigilant follow-up imaging and forgoing external beam radiotherapy unless there is a documented recurrence of his craniopharyngioma.