Ear and hearing health in Aboriginal and Torres Strait Islander people aged 15 years and older: A scoping review

OBJECTIVE

Review empirical research investigating the prevalence, experiences and management of hearing loss and ear disease in Aboriginal and Torres Strait Islander adults.

DESIGN

Scoping review.

STUDY SAMPLES

Searches of four electronic databases, Advanced Google, and key webpages identified 16,373 studies - 21 met inclusion criteria: original research relating to hearing/ear health and Aboriginal and Torres Strait Islander adults.

RESULTS

Fourteen studies measured prevalence of hearing loss or middle-ear dysfunction, with a rate of hearing loss at an estimated 50% (reports ranging from 8% to 100%). Five studies reported views, attitudes, and experiences of hearing loss, with results showing hearing loss negatively impacted individual experiences in health and justice systems, and health professionals had limited understanding of the socioeconomic risk factors of middle ear disease. No articles directly reported on hearing loss management.

CONCLUSIONS

There is a lack of research into the hearing health of Aboriginal and Torres Strait Islander adults, despite its critical importance in addressing health and social inequities. Given the widely varying and imprecise estimated rates of hearing loss detected, urgent action is needed to obtain accurate prevalence estimates and, in partnership with Aboriginal and Torres Strait Islander communities, identify the best methods of screening and managing hearing loss.

Student perceptions of two simulated learning environments in paediatric audiology

Objective: To determine audiology student perceptions of two simulated learning environments (SLE) in paediatric audiology.Design: A one-shot case study design.Study sample: Fifteen audiology students who completed questionnaires after participating in two SLEs, one simulating auditory brainstem response (ABR) assessments of neonates in a hospital ward and one simulating visually reinforced orientation audiometry (VROA) assessments of young children in an audiology clinic.Results: The students responded positively to 11/11 areas of audiometric testing and client interaction in both SLEs, to 7/7 aspects of their interactions with the mannequins in both SLEs, and to 8/8 aspects of their interactions with fellow students playing the role of parent in the ABR SLE and 7/8 of these aspects in the VROA SLE. The students reported low levels of anxiety towards both SLEs but rated the ABR SLE more highly than the VROA SLE in areas of preparedness, effectiveness, realism, pre-SLE training, reinforcement of lecture content, and overall usefulness.Conclusions: The participating students responded positively to almost all aspects of both SLEs. Further research is warranted using research designs capable of determining if these SLEs directly improve student abilities as they transition from academic settings to clinical placements in paediatric audiology.

Use of BAER to identify loss of auditory function in older horses

OBJECTIVE

To use the brainstem auditory evoked response (BAER) to test the hypothesis that auditory function could be worse in older horses than in younger horses.

PROCEDURE

BAER waveforms in response to click stimuli were measured in five younger horses (5-8 years) and four older horses (17-22 years).

RESULTS

Compared with the younger horses, the older horses showed significantly (P < 0.02) worse BAER thresholds and significantly (P < 0.02) worse BAER wave V amplitudes to the 90 decibels above normal hearing level stimulus. These results were consistent with partial deafness in the older horse group.

CONCLUSION

BAER assessment can be used to identify partial deafness in older horses. Such horses should be managed appropriately, with particular care taken in noisy environments where hearing loss could put the horse and/or its owner at risk of harm.

NetRaVE: constructing dependency networks using sparse linear regression

NetRaVE is a small suite of R functions for generating dependency networks using sparse regression methods. Such networks provide an alternative to interpreting 'top n lists' of genes arising out of an analysis of microarray data, and they provide a means of organizing and visualizing the resulting information in a manner that may suggest relationships between genes.

AVAILABILITY

NetRaVE is freely available for academic use and has been tested in R 2.10.1 under Windows XP, Linux and Mac OS X.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Automatic grasp planning for visual-servo controlled robotic manipulators

Vision based grasping holds great promise for grasping in dynamic environments where the object and/or robot are moving. The paper introduces a grasp planning approach for visual servo controlled robots with a single camera mounted at the end effector. Sensory control, mechanical, and geometrical issues in the design of such an automatic grasp planner are discussed and the corresponding constraints are highlighted. In particular, the integration of visual feature selection constraints is emphasized. Some quality measures are introduced to rate the candidate grasps. The grasp planning strategy and implementation issues in the development of an automatic grasp planner (AGP) are described. Simulation and experimental results are presented to verify the correctness of the approach and its effectiveness in dealing with dynamic situations.

On the dual structure of the auditory brainstem response in dogs

OBJECTIVE

To use the over-complete discrete wavelet transform (OCDWT) to further examine the dual structure of auditory brainstem response (ABR) in the dog.

METHODS

ABR waveforms recorded from 20 adult dogs at supra-threshold (90 and 70dBnHL) and threshold (0-15dBSL) levels were decomposed using a six level OCDWT and reconstructed at individual scales (frequency ranges) A6 (0-391Hz), D6 (391-781Hz), and D5 (781-1563Hz).

RESULTS

At supra-threshold stimulus levels, the A6 scale (0-391Hz) showed a large amplitude waveform with its prominent wave corresponding in latency with ABR waves II/III; the D6 scale (391-781Hz) showed a small amplitude waveform with its first four waves corresponding in latency to ABR waves I, II/III, V, and VI; and the D5 scale (781-1563Hz) showed a large amplitude, multiple peaked waveform with its first six waves corresponding in latency to ABR waves I, II, III, IV, V, and VI. At threshold stimulus levels (0-15dBSL), the A6 scale (0-391Hz) continued to show a relatively large amplitude waveform, but both the D6 and D5 scales (391-781 and 781-1563Hz, respectively) now showed relatively small amplitude waveforms.

CONCLUSIONS

A dual structure exists within the ABR of the dog, but its relative structure changes with stimulus level.

SIGNIFICANCE

The ABR in the dog differs from that in the human both in the relative contributions made by its different frequency components, and the way these components change with stimulus level.

Ototoxicity and tolerance assessment of a TrisEDTA and polyhexamethylene biguanide ear flush formulation in dogs

Clinically healthy mixed breed dogs (n = 20) were used to determine if a Tris (tromethamine)-buffered test solution, Otinide (Trademark of Dermcare-Vet Pty-Ltd, Australia), containing disodium ethylenediamine tetraacetic acid (EDTA; 1.21 g/L) and polyhexamethylene biguanide (PHMB; 0.22 g/L) caused ototoxicity or vestibular dysfunction. The dogs were randomly assigned to either a control group (group A, n = 10) receiving saline, or a treatment group (group B, n = 10) receiving the test solution. Phase 1 of the study consisted of applying 5.0 mL of saline to both ears of the control group (group A) and 5 mL of test solution to both ears of the test group (group B), for 21 days. A bilateral myringotomy was then performed on each dog under deep sedation. Phase 2 of the study then consisted of applying 2.0 mL of the saline to both ears of the control group (group A) and 2.0 mL of the test solution to both ears of the test group (group B), for 14 days. Throughout the study, dogs were examined for clinical health, and underwent otoscopic, vestibular and auditory examinations. The auditory examinations included brainstem auditory evoked potential (BAEP) threshold and supra-threshold assessments using both click and 8 kHz tone burst stimuli. The absence of vestibular signs and effects on the BAEP attributable to the test solution suggested the test solution could be applied safely to dogs, including those with a damaged tympanic membrane.

The relationship between the auditory brain-stem response and its reconstructed waveforms following discrete wavelet transformation

OBJECTIVE

To examine the relationship between the auditory brain-stem response (ABR) and its reconstructed waveforms following discrete wavelet transformation (DWT), and to comment on the resulting implications for ABR DWT time-frequency analysis.

METHODS

ABR waveforms were recorded from 120 normal hearing subjects at 90, 70, 50, 30, 10 and 0 dBnHL, decomposed using a 6 level discrete wavelet transformation (DWT), and reconstructed at individual wavelet scales (frequency ranges) A6, D6, D5 and D4. These waveforms were then compared for general correlations, and for patterns of change due to stimulus level, and subject age, gender and test ear.

RESULTS

The reconstructed ABR DWT waveforms showed 3 primary components: a large-amplitude waveform in the low-frequency A6 scale (0-266.6 Hz) with its single peak corresponding in latency with ABR waves III and V; a mid-amplitude waveform in the mid-frequency D6 scale (266.6-533.3 Hz) with its first 5 waves corresponding in latency to ABR waves I, III, V, VI and VII; and a small-amplitude, multiple-peaked waveform in the high-frequency D5 scale (533.3-1066.6 Hz) with its first 7 waves corresponding in latency to ABR waves I, II, III, IV, V, VI and VII. Comparisons between ABR waves I, III and V and their corresponding reconstructed ABR DWT waves showed strong correlations and similar, reliable, and statistically robust changes due to stimulus level and subject age, gender and test ear groupings. Limiting these findings, however, was the unexplained absence of a small number (2%, or 117/6720) of reconstructed ABR DWT waves, despite their corresponding ABR waves being present.

CONCLUSIONS

Reconstructed ABR DWT waveforms can be used as valid time-frequency representations of the normal ABR, but with some limitations. In particular, the unexplained absence of a small number of reconstructed ABR DWT waves in some subjects, probably resulting from 'shift invariance' inherent to the DWT process, needs to be addressed.

SIGNIFICANCE

This is the first report of the relationship between the ABR and its reconstructed ABR DWT waveforms in a large normative sample.

On wavelet analysis of auditory evoked potentials

OBJECTIVE

To determine a preferred wavelet transform (WT) procedure for multi-resolution analysis (MRA) of auditory evoked potentials (AEP).

METHODS

A number of WT algorithms, mother wavelets, and pre-processing techniques were examined by way of critical theoretical discussion followed by experimental testing of key points using real and simulated auditory brain-stem response (ABR) waveforms. Conclusions from these examinations were then tested on a normative ABR dataset.

RESULTS

The results of the various experiments are reported in detail.

CONCLUSIONS

Optimal AEP WT MRA is most likely to occur when an over-sampled discrete wavelet transformation (DWT) is used, utilising a smooth (regularity >or=3) and symmetrical (linear phase) mother wavelet, and a reflection boundary extension policy.

SIGNIFICANCE

This study demonstrates the practical importance of, and explains how to minimize potential artefacts due to, 4 inter-related issues relevant to AEP WT MRA, namely shift variance, phase distortion, reconstruction smoothness, and boundary artefacts.

Development of a high-volume aerosol collection system for the identification of air-borne micro-organisms

AIMS

A high-volume aerosol collector was developed to efficiently capture airborne bacteria in order to assess levels of diversity in the air.

METHODS AND RESULTS

Particulate matter was collected on a device designed to filter 1.4 x 10(6) litres of air in a 24 h period on a 1-microm pore size polyester membrane. Methods were optimized for extraction of genomic DNA from the air filter concentrate. Preparation times of 90 s with 0.5-0. 05 mm diameter zirconia/silica beads yielded the highest concentration genomic DNA that was able to support PCR. A 24-h air sample was taken in Salt Lake City, Utah and the microbial composition was determined by the amplification and sequence analysis of 16S ribosomal DNA fragments.

CONCLUSIONS

Sequence analysis revealed a large diversity in the type of microbial species present including clones matching the sequence of Clostridium botulinum. The primary components of the aerosol sample included many different spore-forming bacteria as well as more fragile members of the Proteobacteria division.

SIGNIFICANCE AND IMPACT OF STUDY

The high-volume air collection and genomic DNA recovery system allows for the rapid detection of both cultivable as well as culture-resistant organisms in the environment.

Sequence-specific identification of 18 pathogenic microorganisms using microarray technology

We have developed a Multi-Pathogen Identification (MPID) microarray for high confidence identification of eighteen pathogenic prokaryotes, eukaryotes and viruses. Analysis of amplified products from pathogen genomic DNA using microarray hybridization allows for highly specific and sensitive detection, and allows the discrimination between true amplification products and false positive amplification products that might be derived from primers annealing to non-target sequences. Species-specific primer sets were used to amplify multiple diagnostic regions unique to each individual pathogen. Amplified products were washed over the surface of the microarray, and labelled with phycoerythrin-streptavidin for fluorescence detection. A series of overlapping 20-mer oligonucleotide probes hybridize to the entire diagnostic region, while parallel hybridizations on the same surface allow simultaneous screening for all organisms. Comparison to probes that differ by a single mismatch at the central position reduced the contribution of non-specific hybridization. Samples containing individual pathogens were analyzed in separate experiments and the corresponding species-specific diagnostic regions were identified by fluorescence among their highly redundant probe sets. On average, 91% of the 53 660 pathogen probes on the MPID microarray performed as predicted. The limit of detection was found to be as little as 10 fg of B. anthracis DNA in samples that were amplified with six diagnostic primer-pairs. In contrast, PCR products were not observed at this concentration when identical samples were prepared and visualized by agarose gel electrophoresis.

The importance of pre-analysis windowing on auditory brainstem response fast Fourier transform analysis

Analysis of auditory brainstem response (ABR) frequency content using fast Fourier transform (FFT) analysis has been used to improve ABR sensitivity and specificity as a diagnostic/site of lesion assessment tool, to improve our understanding of ABR components, and to guide ABR stimulus and recording parameter settings. Threatening this success, however, is the literature's poor control of pre-FFT windowing of the ABR prior to ABR FFT analysis. This study examined the significance of using no (NW), vs Blackman (BW), vs modified Blackman (MBW) pre-FFT windows on the FFT analysis of ABRs recorded from normal subjects. Pre-FFT windowing was shown to significantly reduce (p < 0.00005) ABR FFT magnitudes, but not frequencies, with BW causing greater reductions than MBW. The high significance of these results shows that choice of pre-FFT window is critical in any ABR FFT analysis.

Use of the CID W22 as a South African English speech discrimination test

South Africa currently lacks a pre-recorded South African English (SAE) specific speech discrimination test. In the absence of such a test, the SAE speaker recording (Tygerberg recording) of the American (USA) English (AE) CID W22 wordlists--in combination with the original American CID W22 normative data--is the most widely used alternative. The reliability and validity of this method, however, has never been formally assessed. This study assessed the performance of 15 normal hearing, female, first language SAE speakers on the first two full-lists of Tygerberg CID W22 recording at 20, 30, 40, 50, 60 and 70 dBSPL, and compared their scores to the American CID W22 wordlist normative data. Overall, the South African subjects performed worse than the original American normative data at the lower presentation intensities (< 50 dBSPL). Use of the Tygerberg CID W22 recording--with the original American CID W22 normative data--for near threshold assessment of SAE speaking subjects was therefore concluded to be problematic. Use at suprathreshold intensities (> 40 dBSPL), however, was considered a viable option. These results reiterate the need for large scale, South African specific normative studies for the CID W22 wordlists if they are to continue their role as the dominant speech discrimination wordlists in South Africa.

The auditory brainstem response--are South African ENT's missing the point?

The use and misuse of the auditory brainstem response (ABR) test by hearing professionals is often related to the extent and nature of the training they have received. This study used a postal survey based questionnaire to investigate the levels of training in, knowledge about, and appropriateness of referral for, ABR testing in Ear, Nose and Throat (ENT) surgeons and registrars in Gauteng, South Africa. Thirty-seven actively practising ENT specialists and registrars were sampled using a convenience sampling technique. Overall, a poor level of training and knowledge in ABR and its related areas of audiology was identified. This was mirrored by a high demand for further education. Considering the prevalence of auditory disorders in South Africa, and the push towards primary care and early intervention, this study's results highlight the need for improved training in ABR for ENT surgeons and registrars.

Acute Ginkgo biloba facilitates decision-making in a working memory task in rats

Rapid communication

Use of the NAL-AB wordlists as a South African English speech discrimination test

South Africa still lacks a South African English specific speech discrimination test. As an alternative, this study investigated the use of the Australian English, National Acoustic Laboratories Arthur Boothroyd (NAL-AB) wordlists to assess the speech discrimination of South African English speakers. Thirty South African English speakers were tested at 0, 5, 10, 20 and 25 dBHL (audiometer dial reading) and their performance-intensity functions were compared qualitatively to the NAL-AB wordlist normative data. Results showed three general patterns; similar performance for both groups; poorer performance by the South African English speakers at the low to mid presentation intensities only; and poorer performance by the South African English speakers across most presentation intensities. Use of the NAL-AB wordlists at threshold levels or for site of lesion assessment was therefore concluded to be unwise. Use of these wordlists at supra-threshold levels, however, would provide a valid and reliable option for the speech discrimination assessment of South African English speakers.

Regulation of the hypoxia-inducible transcription factor 1alpha by the ubiquitin-proteasome pathway

HIF-1alpha (hypoxia-inducible factor 1alpha) is a basic-helix-loop-helix PAS (Per/Arnt/Sim) transcription factor that, under hypoxic conditions, dimerizes with a partner factor, the basic-helix-loop-helix/PAS protein Arnt, to recognize hypoxia-responsive elements of target genes. It has recently been demonstrated that HIF-1alpha protein but not mRNA levels are dramatically up-regulated in response to hypoxia. Here we show that inhibitors of 26 S proteasome activity produced a dramatic accumulation of endogenous as well as transfected HIF-1alpha protein under normoxic conditions, whereas the levels of Arnt protein were not affected. HIF-1alpha was polyubiquitinated in vivo under normoxic conditions, indicating rapid degradation via the ubiquitin-proteasome pathway. This degradation process appeared to target a region within the C terminus of HIF-1alpha. Importantly, HIF-1alpha ubiquitination was drastically decreased under hypoxic conditions. Up-regulation of HIF-1alpha protein by proteasome inhibitors did not result in transcriptional activation of reporter genes, indicating either the requirement of additional regulatory steps to induce functional activity of HIF-1alpha or the inability of polyubiquitinated forms of HIF-1alpha to mediate hypoxic signal transduction. In support of both these notions, we demonstrate that HIF-1alpha showed hypoxia-dependent translocation from the cytoplasm to the nucleus and that this regulatory mechanism was severely impaired in the presence of proteasome inhibitors. Taken together, these data demonstrate that the mechanism of hypoxia-dependent activation of HIF-1alpha is a complex multistep process and that stabilization of HIF-1alpha protein levels is not sufficient to generate a functional form.

Assessment of Phenotypic Variability in Erwinia stewartii Based on Metabolic Profiles

One hundred twenty-four bacterial isolates originating from sweet corn or corn flea beetles in the northeastern, midwestern, and mid-Atlantic United States were verified as Erwinia stewartii (Pantoea stewartii subsp. stewartii) and characterized phenotypically by their respiratory response to 91 carbon sources. The unweighted pair group method of averages (UPGMA) was used to construct a dendrogram that revealed homogeneous metabolic profiles at 93% similarity. Two-thirds of the isolates formed 18 separate groups, each sharing the same metabolic profile. One-third of the isolates had distinct metabolic profiles. Most groups shared either isolation source, geographical location, and/or year of isolation. Members of some groups persisted through time and had been isolated from diverse geographical locations. Four representative strains of the proposed Pantoea stewartii subsp. indologenes were also characterized; their metabolic profiles were most similar to those of Erwinia herbicola (Pantoea agglomerans).

Utilization of the Denny-Brown collection: differential recovery of forelimb and hind limb stepping after extensive unilateral cerebral lesions

The Denny-Brown collection of primate lesion material was used to test the hypothesis that there is a difference in the rate of forelimb and hind limb recovery of locomotor movements after major unilateral cerebral ablation (pre/postcentral gyrus, decortication or hemispherectomy). The results indicate that, following major cerebral injury, hind limb recovery precedes that of the forelimb in adolescent and adult primates, but not in infants. This suggests that there is an underlying physiological basis to the widely-held belief that, in humans, lower limb recovery after stroke is generally more complete than that of the upper limb.

Perseverative errors and reversal of a visual discrimination following basal forebrain lesions in the rat

Rats with electrolytic lesions of the nucleus basalis magnocellularis were compared to sham-lesioned rats in the retention of a continuously reinforced lever-pressing response and in the acquisition and reversal of a visual discrimination task. The muscarinic agonist pilocarpine, in conjunction with the peripheral muscarinic antagonist methyl-scopolamine, was administered in three doses to subsets of each group during acquisition. The lesion interfered with retention of the lever-pressing response. It did not affect the rate of acquisition of the visual discrimination, but facilitated reversal, and increased the number of perseverative errors made by the rats. Pilocarpine's only notable effect was to increase the latency to respond.

Identification of Erwinia stewartii by a ligase chain reaction assay

A PCR-coupled ligase chain reaction (LCR) assay was developed to distinguish the plant pathogenic bacterium Erwinia stewartii from other erwiniae. This new technique allows discrimination to the species level on the basis of a single-base-pair difference in the 16S rRNA gene which is unique to E. stewartii. Portions of the 16S rRNA genes of E. stewartii and the closely related Erwinia herbicola were sequenced. From comparison of the two 16S rRNA gene regions, two primer pairs were constructed such that only E. stewartii DNA gave a product in the LCR assay. The ligated product was separated from the radioactively labelled primers by denaturing polyacrylamide gel electrophoresis and visualized by autoradiography. Twenty-four different Erwinia species and strains were tested by PCR-coupled LCR to verify the specificity of the assay, and only E. stewartii strains gave a positive reaction. In addition, infected and healthy plant material was also assayed. E. stewartii was detected in infected plant material, even when large populations of epiphytic bacteria were present. No enrichment was necessary for detection of the pathogen in corn leaves. This assay has potential as a diagnostic technique for the detection of E. stewartii in infected plant and vector material.

Expression and prognostic significance of estrogen and progesterone receptors in adenocarcinoma of the uterine cervix. An immunocytochemical study

BACKGROUND

Adenocarcinoma of the uterine cervix typically is an aggressive neoplasm with a propensity for early invasion and dissemination. Little data are available correlating histologic, histochemical, or immunocytochemical parameters with the biologic behavior of this neoplasm. Specifically, the implication of expression of estrogen and progesterone receptors in cervical adenocarcinoma is essentially undefined.

METHODS

An immunocytochemical hormone receptor assay using specific monoclonal antibodies against estrogen receptors (ER) and progesterone receptors (PgR) was used to study paraffin-embedded specimens from 54 patients with primary cervical adenocarcinomas. The specimens were evaluated for heterogeneity and intensity of staining. An attempt also was made to study the relationship between the pattern of hormone receptor expression and other established prognostic indicators.

RESULTS

In all patients, diffuse positive staining of benign endocervical epithelial or stromal cells was observed. Positive immunostaining was seen in the adenocarcinoma specimens of 16 of 54 (30%) patients for ER and 19 of 54 (35%) patients for PgR. Expression of ER and PgR statistically correlated with each other (P = 0.0001). Endocervical-type adenocarcinoma had the highest degree of staining for both ER and PgR. Clear cell carcinomas and intestinal-type carcinomas were negative for both receptors. Positivity for ER and PgR inversely correlated with histologic grade as defined by the International Federation of Gynecology and Obstetrics (FIGO). The relationship between hormone receptor expression and FIGO stage was not statistically significant. Survival was associated with clinical stage (P = 0.004) and with immunocytochemical status of ER expression (P = 0.032) and PgR expression (P = 0.009).

CONCLUSIONS

This study of 54 specimens from patients with cervical adenocarcinoma suggests that positive expression of ER and PgR is associated with prolonged survival.

Antibody to hepatitis C virus increases with time on hemodialysis

We studied whether chronic hemodialysis is associated with an increased risk of exposure to hepatitis C virus. Utilizing a first generation Elisa assay (C-100 Elisa, Ortho Diagnostic Systems, Raritan, NJ) and the Chiron RIBA HCV second generation assay (RIBA, Chiron, Emeryville, CA and Ortho Diagnostic Systems, Raritan, NJ), antibody to HCV was found in 31 of 87 hemodialysis patients (36%). Patients on hemodialysis less than 2 years had an antibody incidence of 15% (n = 46), as contrasted with a 59% incidence for patients on dialysis greater than or equal to 2 years (n = 41). We were unable to demonstrate a correlation of HCV-antibody positivity with history of blood transfusion. The overall incidence is higher than previously reported for hemodialysis patients in the United States. The very high incidence found in patients on dialysis greater than or equal to 2 years suggests that factors in the hemodialysis unit might contribute to the spread of virus.

Combined reconstruction of the anterior cruciate ligament in competitive athletes

Fifty-eight professional and competitive amateur athletes had a combined reconstruction of the anterior cruciate ligament, with use of the semitendinosus tendon for the intra-articular portion of the reconstruction and a strip of iliotibial band for the extra-articular augmentation. Thirty patients (thirty-two knees) were evaluated two to seven years postoperatively to assess the results and the ability to return to athletics. Follow-up consisted of an interview, clinical and roentgenographic examinations, and testing with an arthrometer. Six patients (20 per cent) had a rating of excellent; twenty-two (73 per cent), good; and two (7 per cent), fair. There were no poor results. Of the thirty-two knees, twenty had an associated injury: twenty meniscal tears in eighteen knees, three tears of the medial collateral ligament, four osteochondral fractures of the lateral femoral condyle, and two loose bodies. Combined reconstruction of the anterior cruciate ligament resulted in improved stability of the knee in these patients whose goal of treatment was to be able to resume sports at a highly competitive level.

Intraoperative autologous transfusion in revision total hip arthroplasty

The records of ninety-eight patients (100 hips) who had revision total hip arthroplasty were reviewed to evaluate the efficacy of intraoperative autologous transfusion in reducing homologous blood-transfusion requirements. In the fifty hips in the study group, a mean of 685 milliliters of autologous blood, or 47 per cent of the estimated loss of blood, was transfused intraoperatively. During the entire course of hospitalization, the mean of the total homologous blood-transfusion requirements was 795 milliliters in thirty-nine study-group patients, compared with 1160 milliliters in forty-six control-group patients who did not have autologous transfusion. This difference was statistically significant (p less than 0.029). Eleven patients in the study group and four patients in the control group did not receive homologous blood. Over-all, the use of intraoperative autologous transfusion was directly responsible for a 42 per cent reduction in the total amount of homologous blood that was transfused.

Synovial chondromatosis

Two patients were evaluated for a complaint of long-standing hip pain. No etiology of their progressively disabling symptoms was found by routine diagnostic studies. Hip arthrography and arthrotomography in each case, however, demonstrated multiple intraarticular filling defects consistent with nonradiopaque loose bodies. These were subsequently confirmed at arthrotomy. Synovial chondromatosis is a rare disease in which intrasynovial cartilage metaplasia results in multiple intracapsular loose bodies. Its presence in plain radiographs is uncommon, but has been previously documented. This can account for frequent long delays in accurate diagnosis. Arthrography and/or arthrotomography, however, can be key diagnostic tools. They are recommended in the evaluation of patients whose relatively normal initial clinical examination, laboratory, and roentgenographic studies fail to adequately explain the presence of genuinely disabling symptoms.

Effect of blood pressure on medial medulla-induced muscle atonia

Stimulation of the medial medullary reticular formation (MMRF) has long been reported to produce generalized inhibition of skeletal muscle activity. However, several studies have reported that in most cases MMRF stimulation produces only increases in muscle tone. In the present investigation we have found that blood pressure is a critical variable, determining whether MMRF stimulation will produce muscle excitation or inhibition. When mean arterial pressure (MAP) was greater than 80 mmHg but less than 148 mmHg, MMRF stimulation produced muscle antonia. Reductions of blood pressure by pharmacological or mechanical techniques induced a reversal of response to MMRF stimulation; stimulation that produced inhibition in base-line conditions produced excitation after MAP reduction. MAP reductions of as little as 10% could cause the reversal response. In contrast, the EMG reduction to MMRF stimulation was not changed or was augmented when MAP was raised. MMRF induced atonia, and its reversal by blood pressure reduction persisted after bilateral isolation of the carotid sinus combined with vagotomy, and in the 6-hydroxydopamine-treated cat. Spinal transection at the cervicothoracic junction did not block atonia or the reversal response. It is suggested that the reversal is mediated centrally.

High resolution surface coil magnetic resonance imaging of the spine: normal and pathologic anatomy

In a brief two year period, magnetic resonance imaging of the spine has developed from a single slice, low signal/noise ratio, extremely time consuming technique to a multiplanar, high resolution examination that can be performed in a time frame similar to that of CT imaging. MR has already assumed a primary imaging role in myelopathic states. It is premature to evaluate its place vis-a-vis CT and myelography in many other disease states of the spine, but clearly, MR is assuming an ever expanding role. As technical improvements continue, it is perhaps realistic to predict that magnetic resonance will, in the near future, assume a dominant role in the imaging of the spine for the demonstration of most types of spinal disease.

Postnatal development of respiratory and vocal responses during aversive classical conditioning in cats

Respiratory rate, respiration amplitude, and vocal responses were recorded in cats of different ages during classic conditioning. Vocal responses to the conditional stimulus (CS) appeared first in 8-week-old kittens, and became prominent at older ages. An increase in respiration rate occurred after the onset of the CS in cats of all ages. Similarly, the decrease of respiration amplitude was observed at all ages, but only in 8-week-old and older subjects did this response resemble an adult pattern. In 4-week-old kittens the response was characterized by an early and brief peak, suggesting an alpha conditional response (CR). Clear and significant discrimination between a warning and a safety signal was present in both respiratory and vocal responses after the age of 8 weeks.

Postnatal development of heart rate patterns elicited by an aversive CS and US in cats

Heart rate and motor responses were recorded in cats of different ages during classical conditioning. A deceleratory-acceleratory heart rate pattern observed during the CS-US interval in one- and four-week-old kittens is an alpha conditioned response, a potentiated original response to the CS. At eight weeks of age two new distinct patterns of pure acceleration or pure deceleration are acquired during conditioning and in the absence of motor learning. At 12 weeks of age and in adult subjects, heart rate patterns during the CS-US interval become more complex and conditioned motor responses can be observed. A covariance of HR acceleration and motor responses during the CS-US interval is absent in eight-week-old subjects, but quite high in 12-week-old subjects and adult cats. The data are interpreted as suggesting separate elicitatory mechanisms of HR and motor responses which may show synchrony later in ontogeny.