Localization of acetylcholine receptors and cholinesterase on nerve-contacted and noncontacted muscle cells grown in the presence of agents that block action potentials

The possible role of nerve activity in triggering changes in the localization of acetylcholine receptors (AChRs) and cholinesterase (ChE) on nerve-contacted Xenopus muscle cells has been assessed. The localization of these molecules was examined on nerve-contacted and noncontacted muscle cells in cultures of spinal cord and myotomal muscle derived from Xenopus embryos. Sites of high AChR density were revealed by staining with fluorescent alpha-bungarotoxin and sites of ChE localization were revealed histochemically. Localization of AChRs and ChE at sites of nerve-muscle contact occurred when the culture medium contained 1.2 micron tetrodotoxin (TTX), 1.2 micron TTX, 10 mM magnesium, and no calcium salts, 1.2 micron TTX and 2 mM manganese, or 106 mM potassium methyl sulfate instead of sodium chloride. The nerve-contacted muscle cells in each of these modified culture media also exhibited a reduced incidence of AChR and ChE patches away from the site of contact. It is concluded that the neural factor(s) that triggers the local and remote changes in AChR and ChE distribution can be supplied to the neurites and externalized in the absence of nerve impulses, and that the nerve and muscle cells can interact even when they are largely depolarized.     

Localized osteolysis in stable, non-septic total hip replacement

We are reporting four cases of extensive, localized bone resorption adjacent to a rigidly anchored, cemented total hip replacement. None of these hips showed evidence of infection on clinical, bacteriological, or pathological evaluation. The tissue from the regions of osteolysis showed sheets of macrophages and foreign-body giant cells invading the femoral cortices. Abundant methylmethacrylate particulate debris was present in the tissues, but polyethylene wear debris was absent. The histological appearance of this tissue resembled that reported about loosened total hip implants with the exception of the synovial-like layer at the cement surface. The cases reported here show that aggressive bone lysis may occur around stable cemented total hip arthroplasties without the presence of sepsis or malignant disease.     

Study on extensive lymph node dissection: metastatic lymph nodes in papillary carcinoma of the thyroid

Bilateral cervical lymph node dissection was performed in 71 cases of papillary thyroid carcinoma, considered to be relatively early cases because of mobility, irrespective of the size of tumor or presence of node enlargement. Of these, 33 cases received additional node dissection of the anterosuperior mediastinum through longitudinal sternotomy. The number of lymph nodes examined per subject averaged 89.9, the number of metastatic nodes was 13.8, and metastasis was noted in 88.7% of all cases. Lymph node metastasis tended to be more frequent on the affected side, but was simultaneously scattered over the whole cervical area. As to sites, metastasis of paratracheal nodes on the affected side occurred at a frequency of 66.2%, inferior and superior jugular nodes at 62.0% and 59.0% respectively, pretracheal nodes at 50.7%, and tracheoesophageal nodes at 47.9%. The high incidence of para- and pretracheal nodes suggests that the lymph flow in this direction is of great importance in metastasis. In fact, lymph nodes in the mediastinum, which were directly continuous with these nodes, showed as high as 39.4% metastasis in cases of anterosuperior mediastinal extirpation. This extensive node dissection is considered to be very preferable as at least the agony of survival with carcinoma can be lessened.     

The transcranial Doppler in the adult. Preliminary results in 31 patients

Non-invasive transcranial Doppler US investigation in adult patients was first described by Aaslid et al. (1982). The apparatus consists in a 2 MHz bidirectional pulsed Doppler with spectrum analyser. Middle and anterior cerebral arteries were insonated by transtemporal exploration, basilar artery by occipital foramen. The criteria of identification were: position and angulation of the probe, direction of the flow, depth of sample volume. The authors present a first series of 31 patients, all with cervical CW Doppler and B-mode Echo. The percentage of identification was: MCA 72%; ACA 69%; BA 54%. Some clinical cases are illustrated. The interest of the method is emphasized in spite of constraints depending on probe position and anatomical variability of the circle of Willis: ambulatory and non-invasive methods; assessment of intracranial blood flow in various conditions: cerebral ischemia and infarction, intracerebral angioma; complementarity with other non-invasive and non-expensive techniques: EEG and cervical US investigation.     

The influence of alcohol on the outcome of automated static perimetry

It is well known that perimetric findings fluctuate within a single examination. There is additional fluctuation between perimetric examinations. The cause of this fluctuation is not yet fully understood, but such things as changes in attention, patient cooperation, or drugs have been discussed. To study such possible factors, we carried out perimetry on subjects who had consumed alcohol and who had not. The results indicate that alcohol, at a blood concentration of approximately 0.08%, barely influences the results of static automated perimetry. Differential light sensitivity remained unchanged by alcohol at all eccentricities tested. A decrease in the ability to cooperate was manifested by a significant higher score of false-positives in catch trials. There was also a tendency toward an increase in false-negative responses in catch trials, an increase in the number of stimuli presentations required, and higher short-term fluctuation. Lack of the influence of alcohol on the differential light threshold does not necessarily mean that alcohol has no influence on visual function. It indicates, however, that differential light sensitivity, as measured with the automated perimeter Octopus, is not influenced by moderate alcohol ingestion.     

Comparison of onset and steady-state responses of hearing aids: implications for use of the auditory brainstem response in the selection of hearing aids

Input-output (I/O) functions of hearing aids were measured in response to a 2000-Hz tone burst, having 0.5 ms rise/fall time and 10 ms duration. I/O functions, measured with a hearing-aid analyzer, served as reference conditions. Hearing-aid outputs at onset and during the steady-state portion of the waveform differed; these differences often depended upon stimulus rate. The relation between onset and steady-state estimates of output were not always predictable from hearing-aid attack and release times. These findings indicate that the steady-state output limitation characteristics of hearing aids cannot be estimated from their onset responses. In turn, this suggests that ABR measurements may not provide accurate estimates of the compressive characteristics of hearing aids.     

Quantity of Eimeria spp. oocyst elimination in sheep

In the present paper, the results obtained are shown after a study by means of multivariant statistical analysis, of the quantity of Eimeria spp. oocyst elimination in sheep, bearing in mind the variations observed in the different areas, in the different age-groups, from month to month, and from year to year. Climatic factors, development of immunity, lambing seasons, and poor hygienic conditions seem to be the factors responsible for the statistically significant differences found when analysing the aforementioned main effects.