An evaluation of two signal-processing hearing aids

Various forms of signal processing are used in modern ASP hearing aids. The present study investigated the relationship between sentence recognition ability and two types of signal processing used in commercially available hearing aids. Results indicated a significant improvement in sentence recognition ability employing an instrument with adaptive compression (variable release time) versus an instrument with an adaptive high-pass filter with short attack and release times. Data were obtained for a single-talker competing message at several message-to-competition ratios. The adaptive compression system may prove to be beneficial to hearing-impaired listeners in certain background noise environments.     

Molecular genetics and transfusion management in a child with Bernard Soulier syndrome.

We present a case of Bernard Soulier syndrome in a 9-year-old boy caused by a novel genetic mutation. This child was shown to be homozygous for a single nucleotide deletion (c.1077delG) in the GP1BA gene not previously reported. Clinically, the boy has become refractory to platelet transfusions with both allo-antibodies and iso-antibodies and a massive transfusion requirement for ongoing haemorrhage. We describe the critical role that the blood product transfusion continues to play in the management of Bernard Soulier syndrome and discuss therapeutic options in these patients.     

Using an artificial neural network to diagnose hepatic masses

Using abdominal ultrasonographic data and laboratory tests, radiologists often find differential diagnoses of hepatic masses difficult. A computerized second opinion would be especially helpful for clinicians in diagnosing liver cancer because of the difficulty of such diagnoses. A back-propagation neural network was designed to diagnose five classifications of hepatic masses: hepatoma, metastic carcinoma, abscess, cavernous hemangioma, and cirrhosis. The network input consisted of 35 numbers per patient case that represented ultrasonographic data and laboratory tests. The network architecture had 35 elements in the input layer, two hidden layers of 35 elements each, and 5 elements in the output layer. After being trained to a learning tolerance of 1%, the network classified hepatic masses correctly in 48 of 64 cases. An accuracy of 75% is higher than the 50% scored by the average radiology resident in training but lower than the 90% scored by the typical board-certified radiologist. When sufficiently sophisticated, a neural network may significantly improve the analysis of hepatic-mass radiographs.     

Antimicrobial activity of various immunomodulators: independence from normal levels of circulating monocytes and natural killer cells.

The effects of 89Sr treatment on the natural host resistance of CD-1 mice and the enhancement of resistance by immunomodulators to infection with Listeria monocytogenes or herpes simplex virus type 2 (HSV-2) were determined. In the CD-1 mouse, single-dose treatment with 89Sr caused a profound decrease in the number of circulating monocytes (Mo), lymphocytes, and polymorphonuclear leukocytes (PMN) within 1 week. There was also marked functional impairment of the Mo inflammatory response, as well as markedly decreased spontaneous and activatable cytotoxicity by splenic natural killer (NK) cells. Despite this profound cellular suppression, there was no significant change in natural resistance of CD-1 mice to L. monocytogenes or HSV-2 infection. Furthermore, prophylactic treatment of mice with the biologic immunomodulator Corynebacterium parvum or the synthetic immunomodulators maleic anhydride-divinyl ether or avridine in liposomes resulted in comparable enhancement of resistance in 89Sr-treated and normal mice. These data indicate that natural and immunomodulator-enhanced resistance of CD-1 mice to microbial infections do not depend on normal levels of Mo, PMN, or NK cells. The resistance enhancement may rely on activated tissue macrophages (M phi). In contrast to the early changes in circulating leukocytes, the resident peritoneal cell populations were not markedly altered until after day 30. There then was a distinct decline in lymphocytes and a gradual decline in M phi; the change in M phi was apparently due to the lack of an age-related increase in the peritoneal M phi population in 89Sr-treated mice in comparison with a slight increase in resident M phi in normal mice. After CD-1 mice were treated with 89Sr, the number of PMN and the function of NK cells generally recovered by about day 50 and was followed by partial recovery of circulating Mo, unless a second dose of 89Sr was administered.     

Effect of inapparent murine hepatitis virus infections on macrophages and host resistance

Inapparent infections of mice with murine hepatitis virus (MHV) altered host resistance to experimental infection with a second virus, encephalomyocarditis virus (EMC), reduced the protective effects of exogenously administered interferon against EMC infections, and it altered macrophage ectoenzyme phenotypes in two macrophage populations. Resident peritoneal macrophages from mice experimentally infected with one of two strains of MHV also demonstrated altered ectoenzyme phenotypes. These data demonstrate that inapparent infections with MHV alter several host resistance and macrophage parameters and directly demonstrate that effects of inapparent MHV infection on macrophage parameters can be reproduced experimentally.     

Intraosseous epidermoid inclusion cyst in a great toe. A case report and review of the literature

Epidermoid inclusion cysts are benign lesions that occasionally occur in the distal phalanges of the fingers but are less frequently identified and underreported in the toes. We describe a 55-year-old man with a history of work-related trauma followed by painful expansion of his right great toe, resulting in great anxiety. Imaging studies revealed a radiolucent lesion in the distal phalanx of his right hallux. Clinical differential diagnoses included the possibility of an intramedullary inclusion cyst and other various radiolucent lesions. During surgery, a cystic lesion that contained creamy material was discovered. Frozen section diagnosis of the lesion was an intraosseous epidermoid inclusion cyst. The lesion was removed and the patient recovered uneventfully. Although it has been reported that an unduly large number of phalangeal cysts have been treated by amputation, the judicious use of intraoperative frozen sections can prevent this scenario.     

Human granulocyte-macrophage colony-stimulating factor (hGM-CSF): identification of a binding site for a neutralizing antibody.

One approach to the localization of functionally active regions of human granulocyte-macrophage colony-stimulating factor (hGM-CSF) is to map the epitopes recognized by neutralizing anti-hGM-CSF monoclonal antibodies. We have defined the epitope recognized by one neutralizing antibody (LMM102) using proteolytic fragments obtained by enzymic digestion of bacterially synthesized hGM-CSF. RP-HPLC fractionation of a tryptic digest resulted in the identification of an immunoreactive "tryptic core" peptide containing 66 amino acids (52% of the protein). Further digestion of this "tryptic core" with S. aureus V8 protease produced a unique immunoreactive hGM-CSF product comprising two peptides, residues 86-93 and 112-127, linked by a disulfide bond between residues 88 and 121. The individual peptides, generated by reduction with dithiothreitol, were not recognized by the antibody. An analog of this peptide has been synthesized chemically and shown to have similar immunoreactivity to the epitope obtained by enzymic digestion. A series of modified peptides has also been synthesized to identify further the region required for antibody recognition.     

Assessment of bioequivalence after subcutaneous and intramuscular administration of urinary gonadotrophins

The objective was to demonstrate bioequivalence between s.c. and i.m. administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio 3:1). In two randomized, single-centre, cross-over studies, 18 healthy volunteers on each formulation were assigned to one of the two administration sequences. Subjects were given single doses of one of the above gonadotrophins after endogenous gonadotrophin production had first been suppressed using high-dose oral contraceptive. Subsequently, rate (Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax and AUC, analysis of variance (ANOVA) was performed on log-transformed data and for tmax ANOVA was performed on ranks. Intramuscular and s.c. injections of Humegon were bioequivalent with respect to the main pharmacokinetic parameters, being AUC and Cmax of FSH absorption. Intramuscular and s.c. injections of Normegon were bioequivalent with respect to the AUC of FSH and not bioequivalent with respect to the Cmax of FSH. For tmax of FSH as well as for most LH variables of both preparations, bioequivalence could not be proven due to the high intra- and interindividual variability and/or concentrations being close to the detection limit. Thus, the main pharmacokinetic FSH variables after i.m. and s.c. administration of Humegon and Normegon were bioequivalent.      

Indomethacin-mediated improvement following middle cerebral artery occlusion in cats. Effects of anesthesia

Focal cerebral ischemia initiates multiple detrimental effects in the brain. Chief among these are the regional development of ischemic edema, decreased local perfusion, altered neuronal function, and eventual infarction. To determine if pretreatment with the cyclo-oxygenase inhibitor, indomethacin, would result in improvement in these parameters, adult cats were given indomethacin or control solvent (4 mg/kg intraperitoneally twice daily) and were studied for periods up to 24 hours after right middle cerebral artery occlusion. The interaction of anesthetic agents with indomethacin was also examined in separate groups of experimental animals using pentobarbital and ketamine. In cats allowed to recover from pentobarbital anesthesia, indomethacin reduced gray and white matter edema at 6 and 24 hours after occlusion (p less than 0.05). This was noted in densely areas (indomethacin = 84.3%, control = 87.5%), "penumbra" regions (indomethacin = 82.5%, control = 85.3%), and in nonischemic zones (indomethacin = 81.5%, control = 82.3%) at 24 hours. Somatosensory evoked potential amplitude and central latency were also improved in the indomethacin group (p less than 0.05), as was cerebral perfusion (p less than 0.05). In animals anesthetized with continuous ketamine administration, cerebral edema and perfusion as well as evoked potentials were not significantly improved in any region by indomethacin. Regional cerebral blood flow in the group was increased by indomethacin in the nonischemic opposite hemisphere (indomethacin = 64.7 cc/100 gm/min, control = 48.5 cc/100 gm/min, p less than 0.05), but not in the penumbra region of the ischemic hemisphere (indomethacin = 15.0 cc/100 gm/min, control = 18.6 cc/100 gm/min, p less than 0.05), when measured 4 hours after occlusion. This suggested a steal phenomenon. Beneficial effects of indomethacin were evident in the presence of pentobarbital, but not after ketamine anesthesia. This suggests a synergism dependent on decreased arachidonic acid production from pentobarbital-stabilized membranes coupled with diminished production of cyclic endoperoxides from available arachidonate due to inhibition of cyclo-oxygenase with indomethacin.