Biochemical and cardiovascular measures in subjects with noise-induced hearing loss

Reports on a potential relationship between noise-induced hearing loss (NIHL) and cardiovascular as well as biochemical measures are controversial. This study compares the means of certain cardiovascular and biochemical measures in subjects with NIHL with those in subjects exposed to similar occupational noise, but demonstrating normal hearing. This might indicate certain predisposing factors for NIHL. Eight hundred noise-exposed subjects were divided into two age-matched hearing groups (NIHL and normal hearing). The results showed that the mean values of all the variables examined in both hearing groups were within the normal range. No significant differences were found between the two groups in terms of the distribution of subjects for the indices measured.

[Hearing loss as a result of basic military training]

Exposure to noise is unfortunately inevitable in military training. The incidence of hearing loss due to basic training was examined in a sample of 1000 recruits before enlistment and after 4 months of basic training. Audiometric tests and personal questionnaires revealed that after basic training 33.7% had developed hearing loss in the high frequency range (6-8 KHz), 3% had noise-induced hearing loss (2-5 KHz), while 60% still had normal hearing and 3.5% had hearing impairment due to various other causes. The left ear was more often affected and there was a tendency towards greater damage to hearing in lightly pigmented subjects. An initial hearing loss at 6-8 KHz may be related to individual susceptibility to noise-induced hearing loss.

Effects of hypothermia on auditory brain-stem and somatosensory evoked responses. A model of a synaptic and axonal lesion

Auditory nerve brain-stem (ABR) and somatosensory evoked responses (SER) were recorded in cats as body temperature was uniformly lowered from 37 to 27 degrees C. Analysis of the results showed that the alterations in the evoked responses were due to disturbances induced both in axonal propagation and synaptic transmission by the hypothermia. By studying the first wave of the SER, which is solely an axonal event, and by assuming reasonable values for the total synaptic delay and axonal propagation times along the ABR pathway, it was concluded that this lesion model induced an effect on synaptic transmission 1.3-1.7 times greater than that on axonal propagation. There was a strong inverse correlation between wave latency and body temperature, with slightly steeper slopes for the longer latency waves. Wave amplitudes were not correlated with temperature. Furthermore, the wave latencies and amplitudes were generally not dependent on stimulus rate.

Structure and organization of the pel genes from Erwinia chrysanthemi EC16

The pelA and pelC genes from Erwinia chrysanthemi EC16 were sequenced and overexpressed in Escherichia coli cells. These genes and two others from the same strain that were characterized previously encode catalytically related pectate lyase proteins that are involved with the maceration and soft-rotting of plant tissue. The pel genes of strain EC16 were organized as two loosely linked clusters, with two structurally homologous genes in each. The pelA/E cluster also contained the remains of an additional pel gene, the 5' portion of which had been removed by a prior deletion event. Each of the four functional pel genes but not the deleted one contained an efficient rho-independent transcriptional terminator after the translational stop. These and other data indicate that the pel genes are all independently regulated despite their structural homology and tandem clustered organization. Two of the genes, pelA and pelE, encoded proteins that differed greatly in their isoelectric points and ability to macerate plant tissue. A recombinant gene constructed with the 5' portion of pelE and the 3' portion of pelA yielded a chimeric protein with high pectate lyase activity but relatively low maceration activity. This result raised the possibility that the poor maceration ability of the pelA gene product may involve other properties in addition to its low isoelectric point.

Psychoanalysis and the acquisition of knowledge

From the myth of Prometheus to the trial of Galileo, history and literature are replete with examples of the clash between institutionally-bound power structures which exploit ignorance and ignore reality, and those that attempt to develop some movement towards scientific and personal truth. Within society as we know it, the genius or messiah figure and the establishment are bound together in an attempt to establish a relationship which can be of constructive relevance to both. The challenge of incorporating new and disruptive, though not necessarily disintegrative thought on the one hand, is contrasted with an uncompromising attack upon those who would lay claim to the previously exclusive rights of the established organisation and the power which accrued from them. Psychoanalysis today is joined in the battle with internal and external prohibitions against the acquisition of knowledge, which may in time point towards the truth of human personality, behaviour and existence.

Surgical resection of giant metastatic leiomyosarcoma of the heart

A 44-year-old woman underwent a hysterectomy for leiomyosarcoma in 1969. Cardiac invasion was detected in 1981 but the tumor was considered inoperable. In 1985, 16 years after hysterectomy, malignant tamponade developed as a result of a massive tumor arising from the left ventricle. Emergency decompression by median sternotomy and tube thoracostomy was followed a week later by tumor resection and simultaneous excision of a lung metastasis with the aid of cardiopulmonary bypass. The cardiac tumor weighed 719 gm. A residual pelvic tumor found on a computed tomographic scan was subsequently removed. She is alive and well 22 months after the operation. Aggressive surgical resection of cardiac and other metastases of this slowly growing tumor can be lifesaving.

Maturation of auditory brainstem potentials in neonates and infants

Auditory brainstem evoked potentials (ABP) were recorded in 59 healthy neonates and infants whose age ranged from 3 days to 18 months (6 age groups). Latencies of individual waves and the interpeak latencies (IPL) of I-III, III-V and I-V were analysed. A different maturational pattern was observed in the pontomedullary and the pontomesencephalic segments of the brainstem. Latencies of all waves except wave I were longer in male than in female babies. Establishment of normative data related to the technical variables employed by the individual team is a sine qua non prerequisite for adequate neurological evaluation of ABP.

Effects of body temperature elevation on auditory nerve-brain-stem evoked responses and EEGs in rats

ABRs and EEGs were recorded in anaesthetized rats during whole body hyperthermia. ABR amplitudes were decreased during warming, with little recovery as body temperature was lowered. The latencies of the ABR waves decreased with warming and increased with subsequent cooling. The major latency changes were in the later ABR waves. Warming was accompanied by suppression of the EEG. These results point out that ABR evaluation of patients must take into account elevated body temperatures. Since it has been shown that the rat can serve as a model of the effects of heat on man, an attempt is made to relate these ABR and EEG findings in rats to studies of human psychomotor performance during heat exposure.

Radiographic findings in progressive necrotizing "malignant" external otitis

Twenty-three cases of progressive necrotizing (malignant) external otitis were reviewed. Radiographic evaluation was correlated with clinical disease. CT scanning accurately demonstrated subtle foci of involvement in the skull base which may be clinically unsuspected or go undetected with other studies. Central skull base erosion indicates advanced disease and selects those patients requiring extended antibiotic therapy. Soft tissue thickening of the parapharyngeal space and roof of the nasopharynx also implies advanced disease requiring prolonged therapy. Soft tissue improvement can be visualized on CT. While CT scanning demonstrates the progression of bony disease, it cannot be used to follow resolution of central skull base osteomyelitis. Radionuclide scans provide information regarding the overall extent of the inflammatory process.

Hyperactivity, learning disabilities, and alcohol

The United States Food and Drug Administration had issued a warning to women that alcohol consumed during the prenatal period may cause deleterious effects on offspring. The present article examines the professional literature in regard to the history of and research in alcohol consumption by pregnant women. New research findings suggest that maternal alcohol consumption may be the cause for behaviors in children that have led to their being diagnosed as learning disabled. Hyperactivity, short attention span, and emotional lability in children may be the direct result of mothers' drinking during pregnancy. The present paper reaffirms the Food and Drug Administration's warning to pregnant women and potential mothers of the hazards of even mild or moderate drinking during pregnancy and the possible negative effects it may cause on a child's learning and behavior.

Projective identification: the container and reverie as concepts in applied psychoanalysis

This paper discusses theoretical and clinical problems experienced in the assessment and treatment of two borderline patients admitted to a psychotherapeutic community. It is proposed that difficulties encountered were related first to the inability of the therapeutic couple (therapist and nurse) to develop a capacity for reverie and containment essential if pathological projections were to be detoxified and made available for reintrojection by the patient. Second, it is proposed that failure relates to the patients' difficulties in developing normal symbol formation with respect either to thought or behaviour, related retrospectively to excessive splitting and pathological projective identification and prospectively to an inability to experience whole object relationships. This in turn is linked to the patients' attack on those capacities which are present in the therapeutic couple.

Pontomedullary vs pontomesencephalic transmission time. A diagnostic aid in multiple sclerosis

Caudal vs rostral transmission time has been studied in patients with multiple sclerosis (MS). In the majority of the cases, prolongation in latency was more severe in the caudal segment, which suggests that this part of the brainstem is more commonly affected in MS. The difference between pontomedullary and pontomesencephalic transmission time yields a variable that may prove a valuable adjunct in the electrodiagnosis of MS.

Auditory brain stem responses in thyroid dysfunction

A characteristic pattern of ABR was observed in hyper-and hypofunction of the thyroid gland. The most conspicuous change took place in the BSCT. Its value correlated well with the level of serum T4. Dynamic changes of ABR pattern were recorded during the development of myxedema and on return to an euthyroid state. This preliminary study suggests that examinations of ABR may serve as a tool in the overall assessment of thyroid status.

Auditory function of Friedreich's ataxia. Electrophysiologic study of a family

Hearing function and auditory brainstem potentials were evaluated in nine members of three generations of a family affected with Friedreich's ataxia. The characteristic findings were high-frequency sensorineural hearing impairment of varying severity and diminished or absent N1, N2, and N3 responses. These electrophysiologic aberrations correlate topographically with previously reported pathological observations.

Speech discrimination scores at low sensation levels as a possible index of malingering

Persons referred to the clinic for hearing evaluation, aged 17--35 yrs, who during the evaluation yielded inconsistent pure-tone and speech data and were suspected of malingering, were given a monosyllabic Hebraic PB test at 5, 10, 15, and 20 db re their admitted SRT. Group performances were compared at every presentation level to those of normal-hearing young adults. Both groups performed better as levels increased, but the suspected malingerers yielded SDSs at 5, 10, and 15 db significantly higher than controls by 20.8, 12.5, and 5.2 percentage points, respectively. The higher SDSs at low sensation levels (SLs) yielded by the suspected malingerers were assumed to be due to the exaggerated SRTs admitted by them. Furthermore, the performance - vs - level curve of the normals corresponded to that in the literature for English material, while the curve of the suspected malingerers was, in contrast, essentially different. It was concluded that with careful standardization and wide clinical and experimental use, collecting SDSs at low SLs re admitted SRT might produce a potentially valuable additional tool for uncovering malingering.

Auditory brain stem responses in cerebellopontine angle tumors

The characteristic features of auditory brain stem responses (ABSR) are described in seven cases of cerebellopontine angle tumors: five acoustic neuromas, one congenital cholesteatoma, and one meningioma. An attempt is made to correlate the N1 response with the degree of auditory nerve involvement, to gain information about the presence of brain stem displacement, and to evaluate the cranial extension of the lesion by recording responses to contralateral stimuli. The empirical nature of deductions based on crossed stimulation is emphasized. In tumors originating from the VIIIth nerve, the ABSR pattern is characterized by a well-defined N1 complex, indistinct or absent additional responses, and prolonged brain stem conduction time (BSCT) on the affected side whenever its assessment is feasible. Recording from the affected side on stimulation of the contralateral side may show normal responses from stations central to the auditory nerve in cases of small-sized tumors. Medium or large tumors may be accompanied by abnormal N2 and/or N3 responses suggesting involvement of these stations.

Assessment of functional integrity of brain stem auditory pathways by stimulus stress

The effect of increasing the repetition rate of click stimuli on auditory brain stem responses has been studied in young subjects with normal hearing, in old people and in patients with multiple sclerosis. The most conspicuous effects have been observed in the amplitude of the responses, especially waves II and V, and in the value of the brain stem conduction time. Increased stimulation rates may serve as a method for the assessment of the functional status of the lower auditory pathways in diverse pathological conditions.