ABSTRACT
PURPOSE: The objective of this study was to investigate the auditory pathway maturation monitored by auditory brainstem responses (ABR) in infants with hearing loss during the first year of life. ABR were used to estimate hearing thresholds and the effect of early intervention strategies using hearing aids (HA). METHODS: Click-evoked ABRs were measured in 102 infants aged from 0 to 12 months to determine their individual auditory threshold. Early therapy intervention was recommended before 12 months of age and analyzed. To evaluate the effect of hearing amplification on auditory maturation, different subgroups of infants with moderate hearing loss were analyzed and the auditory pathway maturation was determined based on IPL I-V shortening. RESULTS: Overall, 110 ears (54.0% of 204 ears) with mild to profound HL showed threshold changes of 10 dB up to 60 dB in the follow-up ABR testing. HA were prescribed at the age of 3.8 ± 3.9 months. Cochlear implantation (CI) was performed in cases of repeated profound HL at the age of 9.9 months ± 4.5 months. A significant shortening of IPL I-V in all subgroups of infants (with and without risk factors) who received HA was shown and assumed auditory pathway maturation. CONCLUSION: An early intervention using optimally fitted HA influenced auditory pathway maturation and may lead to improvements of hearing thresholds during the first year of life in infants. This study underscores the importance of not only providing HAs to infants, but also controlling for hearing threshold changes ensuring that HAs provide the optimal level of intervention or CI is indicated.
Subject(s)
Hearing Loss, Sensorineural , Hearing Loss , Auditory Pathways , Auditory Threshold , Evoked Potentials, Auditory, Brain Stem , Hearing Loss, Sensorineural/diagnosis , Hearing Loss, Sensorineural/therapy , Humans , InfantABSTRACT
Trimethylphosphate (TMPO) was administered to 50 male and 50 female Wistar rats through their drinking water at doses of 0, 1, 10, or 100 mg/kg body weight up to 30 months. The dosage of 100 mg/kg was reduced to 50 mg/kg in week 54 for reasons of tolerance, and the animals were euthanized in week 100. Additional 10 animals per dose and sex were treated for 12 months and then euthanized for interim analysis. Weakness of the hind limbs, increased incidences of sunken flanks, distended abdomen, and poor general condition were observed in both sexes of the 100/50 mg/kg group beginning with week 46. Food intake was reduced in high dose males. At 10 mg/kg body weights were up to 10% (males) and at 100/50 mg/kg up to 20% (males) or 15% (females) lower than in controls. Mortality was not affected in animals receiving up to 10 mg/kg. At 100/50 mg/kg it was markedly increased, reaching about 70% at week 100. Relatively slight hematologic changes (reduced hemoglobin, hematocrit, erythrocyte counts, increased reticulocyte numbers, and thrombocyte counts as well as a shift in the differential blood count) at 100/50 mg/kg are interpreted as changes most probably secondary to the other toxic effects. Increased cholesterol concentrations in plasma, shifts in the serum protein electrophoresis (males), increased organ weights (females), and an increased incidence of necroses and lymphocytic infiltrations point to a treatment-related effect on the liver at 100/50 mg/kg. Slightly increased protein excretion, increased relative kidney weights, and an increased incidence of chronic progressive nephropathy are considered treatment-related but rather secondary effects at 100/50 mg/kg. At 100/50 mg/kg an increased incidence and severity of bilateral tubular atrophy in the testes was diagnosed. The most important toxic effect was neurotoxicity, consisting of degeneration and loss of nerve fibers in the peripheral nerves and the spinal cord, associated with myopathic changes, and occurring at 100/50 mg/kg. The no-observed-adverse-effect-level, based on the suppression of body weight gain, is 1 mg/kg in males and 10 mg/kg in females. The incidence, time of occurrence, spectrum of types, and localizations of tumors provided no indication of a tumorigenic/carcinogenic effect of the test substance. TMPO is therefore considered not to be carcinogenic in Wistar rats.
Subject(s)
Carcinogens/toxicity , Organophosphates/toxicity , Animals , Body Weight/drug effects , Carcinogenicity Tests , Drinking/drug effects , Eating/drug effects , Eye/drug effects , Female , Male , Organ Size/drug effects , Rats , Rats, Wistar , Water SupplyABSTRACT
PURPOSE: Due to high soft-tissue contrast and multiplanar imaging capabilities MRI is an interesting modality to perform image-guided biopsies. We checked on the feasibility of MR-guided core biopsies of abdominal masses with an open low-field scanner (0.2 Tesla; vertical field axis). METHODS: 9 patients underwent MR-guided biopsies of abdominal target lesions (6 focal liver lesions, two adrenal masses, one pelvic mass). Different MR-compatible core biopsy instruments were used (needle diameters 14G-18G). MR scans during the procedures were obtained applying T1-weighted gradient echo sequences suitable for breath-hold imaging. RESULTS: In each case, needle guidance was reliable, so that the biopsy instrument could be positioned correctly. Multiplanar imaging capabilities enabled even angled approaches to upper abdominal masses to be realized safely. The combination of magnet design and table design offered suitable access to the patient. CONCLUSION: Using an open low-field scanner, MR-guided core biopsies of abdominal masses are practicable.
