CMSS-VEPs: Contrast modulated steady state visual evoked potentials: Its neuronal origin and clinical use

CMSS-VEPs are presented as a sensitive, non-invasive functional investigation technique of the visual function, applicable in clinical practice. New improvements of the technique are presented. The underlying neuronal mechanisms are discussed. The clinical use is illustrated in a case of optic neuritis.     

A Disseminated Alveolar Rhabdomyosarcoma in a 9-Year-Old Boy Disclosed by Chromosomal Translocation (2;13) (q35;q14)

A 9-year-old boy presented with a small subcutaneous tumor of the trunk and diffuse bone marrow involvement. The first histological diagnosis given was undifferentiated malignancy possibly of neural crest origin and chemotherapy was started immediately using vincristine, cyclophosphamide, cisplatin, and teniposide (OPEC). Complete response was achieved after four courses of chemotherapy. Histological slides were then reviewed and the final diagnosis of alveolar rhabdomyosarcoma (RMS) was retained. Moreover, chromosome analysis of malignant cells in the bone marrow revealed a translocation involving chromosomes 2 and 13:t(2;13) (q35;q14). This specific karyotype finding has been recently reported in a few cases and could be specific for alveolar RMS. The patient had a relapse 7 months after diagnosis and died 4 months later.     

Selective modification at the N-terminal region of human growth hormone that shows antagonistic activity

A new analogue of recombinant human growth hormone (hGH), hGH des(1–6,14) was expressed in Escherichia coli, refolded and purified to homogeneity. The mutation decreased the hormone's ability to bind lactogenic and somatogenic receptors through its site 1, and almost completely abolished its ability to bind these receptors through site 2, as evidenced by both binding and gel-filtration experiments. More specifically, the binding to prolactin receptors (PRLRs) from various species or their soluble recombinant extracellular domains (ECDs) was decreased 1.5–4-fold, whereas the binding to hGH receptor (hGHR) was decreased 10–85-fold. These changes caused an almost total loss of hormone agonistic activity in several in vitro bioassays and subsequently, the hGH des(1–6,14) analogue acquired antagonistic properties. This antagonistic activity was dependent upon modification of site 1. In those cases in which the binding was reduced only slightly, e.g. binding to rabbit PRLRs, hGH des(1–6,14) acted as a strong antagonist, whereas in others in which the binding of site 1 was reduced to a higher degree, such as other PRLRs and, in particular, hGHR, the antagonistic activity was correspondingly weaker. Circular dichroism spectra of the analogue suggested that these changes do not result from a decrease in overall -helix content, but rather from minor local structural modifications at the N-terminus.     

Impact of mandibular condyle preservation on patterns of failure in head and neck cancer.

OBJECTIVE: To determine the role of native condyle preservation in local recurrence after segmental mandibulectomy in patients with head and neck squamous cell carcinoma. METHODS: Retrospective chart review with main outcome measuring local control of cancer. RESULTS: Between 1994 and 2003, 72 patients (48 men, 24 women) with an average age of 73.5 years without previous treatment underwent segmental mandibulectomy. Fifty-four cases (n = 54) involved the mandible posterior to the mental foramen and are the subject of this review. In 36 patients, the condyle was preserved and mandibular continuity was restored. In 18 patients, condyle and ramus were resected without mandibular reconstruction. Reconstructive modalities included primary closure (3), split-thickness skin graft (3), pedicle flap (19), and free tissue reconstructions (29). Overall local-regional recurrence rate was 22 percent (12 of 54); no recurrences were identified in patients who underwent condylar resection. Recurrences were observed in patients with mandibular reconstruction by both plate and pedicle flap (5 of 9) or (osteo) myocutaneous free flap (7 of 27). CONCLUSION: Condylar preservation may predispose patients to local recurrence after segmental mandibulectomy. This does not translate into overall reduction in survival.     

Dosimetry associated with exposure to non-ionizing radiation: very low frequency to microwaves

The interpretation of the effects in biological systems exposed to electromagnetic (EM) fields requires knowledge of the internal fields and absorbed energy. The quantification of the specific absorption rate (SAR) is called dosimetry. The SAR given in units of watts per kilogram is a complex function of the source configuration, shape and size of the exposed subjects, orientation of the subject with respect to the source, and the frequency. The average and maximum SAR in the exposed subject may vary over many orders of magnitude for a given exposure level. In order to relate observed biological effects in exposed laboratory animals to safe exposure levels for man, both the fields within the environment and SAR within the exposed tissues must be determined. The environmental fields and the SAR can often be determined from EM theory, but in most cases one must rely on instrumentation such as field survey meters for quantifying the exposure fields and electric field probes, thermocouples, thermistors, fiber optic probes, thermography, and calorimetry for quantifying the SAR in the tissues or equivalent models. A combination of techniques, each valid for a particular model over a particular frequency range, have been used to determine average and peak SARs in humans and animals exposed to plane wave radiation. Though it has been considerably more difficult to quantify these quantities for near field and partial-body exposure conditions, progress is continually being made in this area.     

Lung cancer in Newfoundland, Canada

In this study 1,466 cases of primary lung cancer diagnosed between 1974 and 1983 and reported to the Provincial Tumour Registry, were reviewed. The incidence of lung cancer in Newfoundland has been lower than that in Canada as a whole. The age-adjusted rates for Canadian males and females were 56 and 14 per 100,000 compared to 45 and 7 in Newfoundland. Census division rates showed no association with socioeconomic indicators. The rate in one census division was higher (63 vs 53) most probably because of the higher risk of men who worked in the St. Lawrence fluorspar mines. Although Newfoundland's current smoking rates (39% of men over 15 and 29% of women over 15) are high, this is not reflected in lung cancer rates. Smoking was not widely accepted in rural areas until the time of World War II, and Newfoundland's lower rates may be due to this delay in exposure.     

The depressing effect of tetracaine and ryanodine on the slow outward current correlated with that of contraction in voltage-clamped frog muscle fibres

The effects of tetracaine (10–50 M) and ryanodine (0.1–10 M) were tested on the slow outward K⁺ current (I _so) and the mechanical tension of isolated frog muscle fibres in a voltage-clamp device (double mannitol-gap) connected to a mechanoelectric transducer. In the concentration range tested, both drugs induced a simultaneous inhibition of tension and current. In all cases the effect on tension was twice that on current. The tetracaine-induced current and tension blocks were fully reversible and dose-dependent. In contrast the ryanodine effects on current and tension were not reversible and did not exhibit a dose dependence except for the delay before the onset of the response, which was shortened when the concentration was raised. Linear regression analysis of the time-dependent and dose-dependent effects of both drugs indicated a strong correlation between the decreases in tension and current. It is concluded that the slow outward current is partly under the control of the Ca²⁺ release from sarcoplasmic reticulum during contraction.     

Echography and scintigraphy using technetium 99m pyrophosphate in the diagnosis of cardiac amyloidosis

The diagnosis of amyloid cardiomyopathy was only based, until the last few years, on the results of invasive techniques. It seems presently that the combined contribution of cardiac sonography and scintigraphy using technetium 99m pyrophosphate, makes, most of the time, this diagnosis possible without need for additional examinations. This notion is illustrated by a typical case-report and data from the literature. Demonstration on the cardiac sonogram of a thickening of the walls-while the context and especially the electrocardiogram are not in favor of a left ventricular hypertrophy--associated with a very particular "hyperechoing" aspect and an abnormal fixation on the scintigram, may be considered specific of this disease.     

Fibrillar beta-amyloid peptide Aβ1–40 activates microglial proliferation via stimulating TNF-α release and H2O2 derived from NADPH oxidase: a cell culture study

Background  

Alzheimer's disease is characterized by the accumulation of neuritic plaques, containing activated microglia and β-amyloid peptides (Aβ). Fibrillar Aβ can activate microglia, resulting in production of toxic and inflammatory mediators like hydrogen peroxide, nitric oxide, and cytokines. We have recently found that microglial proliferation is regulated by hydrogen peroxide derived from NADPH oxidase. Thus, in this study, we investigated whether Aβ can stimulate microglial proliferation and cytokine production via activation of NADPH oxidase to produce hydrogen peroxide.     

Nociceptive stimulation activates locus coeruleus neurones projecting to the somatosensory thalamus in the rat

In the thalamus, noradrenergic output from the pontine nucleus locus coeruleus (LC) may actively shape the response properties of various sensory networks en route to the cortex. Little is known, however, about the involvement of ascending noradrenergic innervation of the somatosensory thalamus in the processing of nociceptive information. To address this question, we combined the study of Fos expression upon nociceptive tooth pulp stimulation in the anaesthetized rat, with the detection of retrogradely traced neurones from the somatosensory thalamus. Cell bodies labelled retrogradely from the left thalamus were observed on both sides of the LC, with an ipsilateral predominance ( n = 8). Electrical stimulation of the right incisor pulp ( n = 4) provoked a significantly stronger Fos expression (around twice) than sham surgery ( n = 4), in both the ipsi- and contralateral LC. Significantly larger numbers of double labelled neurones were counted in the LC of tooth-pulp-stimulated animals (representing around 30% of retrogradely labelled cells in LC) than in the LC of sham animals. They were found bilaterally, but with a clear, significant, ipsilateral (i.e. left) predominance. The present data offer an anatomical framework to understand how the LC is involved in the sensory processing of nociceptive information in the thalamus. For the first time, it is shown that nociceptive stimulation activates LC neurones projecting to the somatosensory thalamus. This suggests a new role for LC in modulating nociception within the thalamus.