Ethical and medico-legal issues of TOETVA procedure and simulation on cadavers: a scoping review

Conventional open thyroidectomy is still considered the gold standard for thyroid surgery. Transoral endoscopic thyroidectomy vestibular approach (also known as TOETVA) is often considered to be more advantageous than the other approaches, such as minimally invasive video assisted thyroidectomy, thyroidectomy via breast/axillary/retroauricular access, bilateral axillo-breast approach and axillo-bilateral breast approach. In this scoping review, we discuss the risks and the benefits of this surgical approach and its medico-legal and ethical implications, particularly focusing on the importance of practice on cadavers. Currently, there is little scientific evidence supporting TOETVA, since there are few papers on the comparison with the traditional open thyroidectomy that have been published and thus little data on the long-term outcomes of TOETVA are available. Since the better cosmetic outcome currently represents the main indication for this surgical technique, substantial medico-legal and ethical issues arise. Moreover, practice on cadavers can help surgeons to develop the technical and non-technical skills required to perform efficiently and safely this new surgical procedure.

Transoral endoscopic thyroidectomy by a vestibular approach: cadaver simulation experience and ethicolegal issues

This article describes the use of transoral endoscopic thyroidectomy by a vestibular approach on cadavers to improve the technical and non-technical skills of surgeons.

Household disinfectant exposure during the COVID-19 pandemic: a retrospective study of the data from an Italian poison control center

OBJECTIVE

Since the beginning of the COVID-19 pandemic it has been recommended that chemical disinfectants are used to protect surfaces. This study aimed to determine whether the number of exposure calls related to household disinfectants (HD) received between January 30, 2020 to May 18, 2020 varied from the same time period in the previous year.

MATERIALS AND METHODS

A retrospective review of the poison control center database from the Fondazione Universitario Policlinico Agostino Gemelli IRCCS, Rome, Italy, was conducted. Calls from Italian citizens, hospitals, and general practitioners received during the same time period in 2019 and 2020 were compared.

RESULTS

The center received 1972 exposure calls during the study period. A 5% increase in calls regarding exposure to HDs was noted from 2019 to 2020 (9.8% to 15.2%, p<0.001). The majority of enquiries regarded bleach-containing products, hand sanitizers, ethanol, and hydrogen peroxide. Most calls were received from patients in their homes (n, 259; prevalence, 86%; increase, 107%) and concerned accidental exposure (n, 280; prevalence, 93%; increase, 76%), while cases of intentional exposure decreased (n, 14; prevalence, 5%; decrease, 33%). The main route of exposure was ingestion (n, 170; prevalence, 57%; increase, 45%), but the highest increase was observed in inhalation cases (n, 82; prevalence, 27%; increase, 122%).

CONCLUSIONS

As the incidence of enquiries regarding products that can represent an important health hazard, when improperly used, increased in 2020 suggests that the COVID-19 public health messaging on the proper use of HDs should be improved.

Immunoglobulins G modulate endothelial function and affect insulin sensitivity in humans

BACKGROUND AND AIMS

Data from animals suggest that immunoglobulins G (IgG) play a mechanistic role in atherosclerosis and diabetes through endothelial dysfunction and insulin resistance. Patients with common variable immunodeficiency (CVID), who have low circulating levels of IgG and are treated with intravenous polyclonal IgG (IVIgG), may provide an ideal model to clarify whether circulating IgG modulate endothelial function and affect insulin sensitivity in humans.

METHODS AND RESULTS

We studied 24 patients with CVID and 17 matched healthy controls (HC). Endothelial function was evaluated as flow mediated dilation (FMD) of the brachial artery at baseline and 1, 7, 14, and 21 days after IVIgG infusion in the CVID patients. We measured also plasma glucose, insulin, and calculated the HOMA-IR index. We also investigated the role of human IgG on the production of Nitric Oxide (NO) in vitro in Human Coronary Artery Endothelial Cells (HCAEC). Compared to HC, FMD of CVID patients was significantly impaired at baseline (9.4 ± 0.9 and 7.6 ± 0.6% respectively, p < 0.05) but rose above normal levels 1 and 7 days after IVIgG infusion to return at baseline at 14 and 21 days. Serum insulin concentration and HOMA-IR index dropped by 50% in CVID patients after IVIgG (p < 0.002 vs. baseline). In vitro IgG stimulated NO production in HCAEC.

CONCLUSIONS

Reduced IgG levels are associated with endothelial dysfunction and IVIgG stimulates endothelial function directly while improving insulin sensitivity. The current findings may suggest an anti-atherogenic role of human IgG.

Alopecia neoplastica as a sign of visceral malignancies: a systematic review

Alopecia neoplastica (AN) from visceral tumours is a rare form of cutaneous metastasis in which internal malignancies spread to the scalp. The diagnosis of AN may be very challenging, especially when its onset precedes the diagnosis of the primary tumour. We aimed to improve the knowledge on AN, highlighting that in case of scarring localized alopecia, a differential diagnosis with metastasis should always be considered. We performed a systematic review to describe the main demographic and clinical features associated with AN from visceral malignancies; a survival analysis was also performed. In 118 reports, accounting for 123 patients, we found that women were more affected by AN than men (53.7% vs. 46.3%). The most frequent site of the primary tumour was the gastrointestinal tract (24.4%), followed by breast (17.9%), kidney (8.1%), lung (7.3%), thyroid (7.3%), uterus (6.5%), central nervous system (6.5%), liver (3.3%) and other anatomic areas for 18.7% of cases. Furthermore, in more than half of the cases (66.1%), AN lesions were single and were mainly diagnosed after the primary visceral tumour (71.5%). Finally, survival analysis highlighted a lower progression-free survival in men; while, no significant differences in overall survival were reported among genders. In conclusion, metastatic skin disease should always be taken into consideration when dealing with patients with localized scarring alopecia.

Ficoll-hypaque separation vs whole blood lysis: Comparison of efficiency and impact on minimal residual disease analysis

INTRODUCTION

The high-throughput era remarkably changed molecular laboratory practice. Actually, the increasing number of processed samples requires to reduce the risk of operator biases, by automating or simplifying as much as possible both the analytical and the pre-analytical phases. Minimal residual disease (MRD) studies in hematology often require a simultaneous processing of many bone marrow and peripheral blood samples from patients enrolled in prospective, multicenter, clinical trials, monitored at several planned time points.

METHODS

In this study, we demonstrate that red blood cell lysis (RBL) pre-analytical procedure can replace the time-consuming Ficoll stratification as cell recovering step. Here, we show a MRD comparison study using both total white blood cells and mononuclear cells recovered by the 2 procedures from 46 follicular lymphoma (FL), 15 multiple myeloma (MM), and 11 mantle cell lymphoma (MCL) patients enrolled in prospective clinical trials.

RESULTS

The experiments were performed in the 4 laboratories of the Fondazione Italiana Linfomi (FIL) MRD Network and showed superimposable results, in terms of good correlation (R = 0.87) of the MRD data obtained by recovering blood cells by the 2 approaches.

CONCLUSION

Based on these results, the FIL MRD Network suggests to optimize the pre-analytical phases introducing RBL approach for cell recovery in the clinical trials including MRD analysis.

Pregabalin-induced first degree atrioventricular block in a young patient treated for pain from extrapulmonary tuberculosis

<p>Pregabalin, widely used in the treatment of several pain disorders, is usually well tolerated. Uncommonly, the drug may induce cardiac side effects, rarely prolongation of the PR interval. The latter has never been described in patients with healthy heart or normal renal function. We characterize a unique case of a young man with extrapulmonary tuberculosis and no detectable or known cardiac or kidney diseases, treated with pregabalin to control the severe pain due to the involvement of the spinal cord by the tuberculosis, showing an atrioventricular (AV) block due to pregabalin administration. The reported case emphasizes the need of monitoring PR interval during treatment with pregabalin, even in patients without background of cardiac or renal diseases. </p>

Relationship between Damage Accrual, Disease Flares and Cumulative Drug Therapies in Juvenile-Onset Systemic Lupus Erythematosus

Our objective was to investigate the pattern of damage accumulation in patients with juvenile-onset systemic lupus erythematosus (JSLE) and the relationship between damage accrual, disease flares and cumulative drug therapies. All patients with SLE followed prospectively in three tertiary care centres were identified. Only patients who presented within 12 months of diagnosis and were followed for at least three years were included. Damage was measures based on chart review using the SLICC/ACR damage index (SDI), which was modified (M-SDI) by adding the item growth failure. Mild-moderate and severe disease flares were defined by the increase in SLEDAI-2K. The cumulative duration of drug therapies was calculated in each patient. Fifty-seven patients were included. The mean M-SDI score for the whole patient group increased over time, from 0.1 at one year to 0.8 at three years to 1.5 at five years. Ocular and renal damage and growth failure were observed most frequently. Compared to patients with stable damage, patients who accrued new damage had a significantly greater frequency of severe disease flare in the first three years of follow-up. No significant difference was observed in any cumulative drug therapy between patients who accrued damage and those who did not. Damage accrual was associated with severe disease flares, suggesting that judicious use of immunosuppressive agents to achieve prompt control of severe exacerbation of disease activity is important in minimizing damage in patients with JSLE.

Real-Time PCR and Droplet Digital PCR: two techniques for detection of the JAK2(V617F) mutation in Philadelphia-negative chronic myeloproliferative neoplasms

INTRODUCTION

Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are clonal disorders that present JAK2(V617F) mutation in 50-95% of cases. The main objective of this study was the comparison of two PCR methods, real-time (qPCR) and droplet digital PCR (DD-PCR) for detection of the JAK2(V617F) mutation, to assess analytic sensitivity, specificity, and feasibility of the two methods.

METHODS

Ninety-nine patients with MPN of 225 presenting the JAK2(V617F) mutation by qPCR have been evaluated by DD-PCR also.

RESULTS

We demonstrated an absolute concordance in terms of specificity between the two methods, DD-PCR showing a higher sensitivity (half a log higher than qPCR). As expected, a progressive increase of mutant allele burden was observed from essential thrombocythemia (ET) to polycythemia vera (PV) and primary myelofibrosis (PMF) to secondary myelofibrosis (SMF).

CONCLUSION

In conclusion, our study showed that DD-PCR could represent a new and promising technological evolution for detection of JAK2 mutation in MPNs.

Vasculitides with cutaneous expression in children: clinico-pathological correlations

The most recent pediatric vasculitis classifications (EULAR/PRINTO/PRES) have proposed the use of an integration of clinical signs and symptoms, laboratory data, imaging and pathologic data. Pediatric vasculitis represent a peculiar clinical-diagnostic model, compared to the corresponding adult pathology chapter, and in particular, dermatopathologic aspects of these diseases identify more specific issues, made contingent by crucial variables such as duration of vasculitis lesion, site of the biopsy, proper biopsy depth, and possibility to correlate histopathological findings with immunopathological results. Possible additional diagnostic difficulties may arise from the fact that, in children, the same systemic disease, such as lupus erythematosus, may present with different clinical manifestations, with histopathological features of a precise type of vasculitis specific for that type of clinical manifestation. Examples are provided by hypocomplementemic urticarial vasculitis, cryoglobulinemic purpura, lymphocytic vasculitis of livedoid lesions. This paper describes the cutaneous histopathological findings of some vasculitis related pediatric diseases, be they pertaining to a systemic vasculitis with corresponding cutaneous vasculitis, to a systemic vasculitis with sporadic cutaneous vasculitic involvement, and to a systemic vasculitis without cutaneous vasculitic involvement. Type and level of histopathological vasculitic involvement, caliber of the vessel, type of vasculitis associated infiltrate, are likewise reliable integration in the complex diagnostic path of vasculitis in childhood. On the basis of these criteria dermatopathologists should be confident in identifying the type of the vasculitis and relate them to a specific pediatric disease.

Pompholyx of the hands after intravenous immunoglobulin therapy for clinically isolated syndrome: a paediatric case

Pompholyx is a common eruption of small vesicles on the palms, soles, and/or lateral aspects of the fingers. It has a multifactorial etiology, including genetic determinants, allergy to metals, and id reaction; rarely it is a drug-related side effect. We report a paediatric case of pompholyx of the hands related to the intravenous immunoglobulin (IVIG) therapy for Clinically Isolated Syndrome (CIS). A 10-year-old boy, received an IVIG therapy (Venital, Kedrion Spa, Italy) at a dose of 400 mg/kg daily for five days. The fifth day of IVIG infusion, a symmetrical vesicular eruption appeared on the palms of the hands and on lateral aspects of the fingers. The lesions improved with application of topical steroids in few days. The mechanism of induction of pompholyx by IVIG therapy is unknown. A review of the Literature suggests the hypothesis that dyshidrotic eczematous reactions may be related not only to the type of IVIG, to the dose and the rates of infusion, but also to an allergic response to excipients and preservatives contained in the drug, probably elicited by an underlying neurological disease in some cases.

The c.480C>G polymorphism of hOCT1 influences imatinib clearance in patients affected by chronic myeloid leukemia

The aim of the study was to investigate any possible influence of polymorphisms of transmembrane transporters human organic cation transporter 1 (hOCT1), ABCB1, ABCG2 on imatinib pharmacokinetics in 33 men and 27 women (median age and range, 56 and 27-79 years, respectively) affected by chronic myeloid leukemia. A population pharmacokinetic analysis was performed to investigate imatinib disposition in every patient and the role of transporter polymorphisms. Results showed that the α1-acid glycoprotein and the c.480C>G genotype of hOCT1 had a significant effect on apparent drug clearance (CL/F) being responsible, respectively, for a 20% and 10% decrease in interindividual variability (IIV) of CL/F (from 50.1 up to 19.6%). Interestingly, 25 patients carrying at least one polymorphic c.480 G allele had a significant lower CL/F value with respect to the 35 c.480CC individuals (mean±s.d., 9.6±1.6 vs 12.1±2.3 l h(-1), respectively; P<0.001). In conclusion, the hOCT1 c.480C>G SNP may significantly influence imatinib pharmacokinetics, supporting further analyses in larger groups of patients.

Migraine attack restores the response of vascular smooth muscle cells to nitric oxide but not to norepinephrine

AIM: To clarify whether the vasoconstrictory response is impaired and to study vascular function in patients with migraine during the headache attack.

METHODS: We studied vascular reactivity in the resistance arteries by using the forearm perfusion technique associated with plethysmography. We measured forearm blood flow by strain-gauge plethysmography during intra-brachial infusion of acetylcholine, sodium nitroprusside or norepinephrine in 11 controls and 13 patients with migraine, 11 of them (M) in the interval between the migraine attacks and 4 during a headache attack (MH). Written informed consent was obtained from patients and healthy controls, and the study was approved by the Ethics Committee of the University Federico II.

RESULTS: Compared to healthy control subjects, in patients with migraine studied during the interictal period, the vasodilating effect of acetylcholine, that acts through the stimulation of endothelial cells and the release of nitric oxide, was markedly reduced, but became normal during the headache attack (P < 0.05 by analysis of variance). The response to nitroprusside, which directly relaxes vascular smooth muscle cells (VSMCs), was depressed in patients with migraine studied during the interictal period, but normal during the headache attack (P < 0.005). During norepinephrine infusion, forearm blood flow decreased in control subjects (-40% ± 5%, P < 0.001). In contrast, in patients with migraine, either when studied during or free of the headache attack forearm blood flow did not change compared to the baseline value (-3% ± 13% and -10.4% ± 15%, P > 0.05).

CONCLUSION: In migrainers, the impaired relaxation of VSMCs is restored during the headache attack. The vasoconstrictory response is impaired and remains unchanged during the migraine attack.

Post-surgical lipophagic panniculitis: a specific model of traumatic panniculitis and new histopathological findings

Aim of this work was to define the histopathological features of post-surgical panniculitis. Dermal and hypodermal changes will be analyzed in detail, to understand the cascade of events that characterize the tissue response to surgical trauma. Cutaneous re-excision specimens of cases of basal cell carcinoma, squamous cell carcinoma, and melanoma consecutively seen from January 1, 2011 to June 30, 2011 at the Department of Dermatology, University of Pavia, were included in this study. Only the cases in which the first surgical procedure included the subcutaneous fat, were considered. In addition, the time elapsed from the first surgical procedure and the re-excision had to be included in a period of time from one to three months. All the specimens were stained with hematoxylin and eosin. Thirty cutaneous re-excision specimens were studied. Histopathologic examination revealed changes of epidermis, ranging from slight atrophy to moderate hyperplasia. In two cases focal ulceration was seen, with transfollicular elimination of foreign body material. The main dermal changes observed were the: 1) scar with well defined vertical orientation along the dermal suture line; 2) rounded cicatricial areas with radial branching septa of scarring tissue; 3) foreign body granuloma formation; 4) alignment of hystiocytes at the dermo-hypodermal border; 5) traumatic neuromas. The subcutaneous fat changes included: 1) lobular panniculitis with consistent presence of foam cells; 2) striking anisocytosis with pseudocystic degeneration and necrosis of adipocytes; 3) eritrocyte extravasation, mainly at the dermo-hypodermal border; 4) deep seated phlebitis. Post-surgical panniculitis is a lobular foam cell panniculitis characterized by simultaneous dermal and hypodermal changes, expression of the multi-faceted tissue response to a surgical trauma. This type of peculiar lipophagic response puts post-surgical panniculitis into the wider chapter of lipophage tissue response seen in atherosclerosis, glomerulosclerosis and some infectious models such as Mycobacterium tuberculosis and Chlamydia pneumoniae infections. Furthermore it may be seen as a reliable and convenient model for laboratory investigation on foam cell tissue response.

Panniculitis in children

This paper will give a comprehensive view of the most frequent panniculitides seen in childhood, with emphasis on the types exclusively found in infancy, and for all other types of panniculitides also found in adults. Aim of this paper is also to analyze the clinical differences between panniculitis in childhood and in adulthood, and to give reliable histopathologic criteria for a specific diagnosis. A review of the literature is here integrated by authors' personal contribution. Panniculitides in children is a heterogeneous group of diseases, as well as in adult life, characterized by inflammation of the subcutaneous fat. Only very few types of panniculitis are exclusively found in childhood, such as Sclerema neonatorum and subcutaneous fat necrosis of the newborn, while the vast majority of the other types may be found both in paediatric age and in adults. Furthermore, this paper will consider in detail panniculitis according to their frequency, such as Erythema nodosum, Lupus panniculitis, Cold panniculitis, panniculitis in Behçet disease, and poststeroid panniculitis. It will also describe rare forms of panniculitis, such as Eosinophilic panniculitis (a pathological entity debated by many authors), Subcutaneous panniculitis T-cell lymphoma, and the different forms of the so call "Lipophagic panniculitis", encompassing respectively the febrile relapsing panniculitis of Weber-Christian disease and the non-relapsing form of Rothmann-Makai disease. For each type of panniculitis considered concise information will be given about epidemiology, etiology, clinical findings, laboratory data, prognosis and therapy, while histopathologic findings will be described in detail.

The repetition timing of high frequency afferent stimulation drives the bidirectional plasticity at central synapses in the rat medial vestibular nuclei

In this study we show that high frequency stimulation (HFS, 100Hz) of afferent fibers to the medial vestibular nucleus (MVN) can induce opposite long-term modifications of synaptic responses in the type B neurons depending upon the stimulation pattern. Long burst stimulation (LBS: 2s) and short burst stimulation (SBS: 0.55s) were applied with different burst number (BN) and inter-burst intervals (IBI). It results that both LBS and SBS can induce either N-methyl-d aspartate receptors (NMDARs)-mediated long-term potentiation (LTP) or long-term depression (LTD), depending on temporal organization of repetitive bursts. In particular, the IBI plays a relevant role in guiding the shift from LTP to LTD since by using both LBS and SBS LTP is induced by shorter IBI than LTD. By contrast, the sign of long-term effect does not depend on the mean impulse frequency evaluated within the entire stimulation period. Therefore, the patterns of repetitive vestibular activation with different ratios between periods of increased activity and periods of basal activity may lead to LTP or LTD probably causing different levels of postsynaptic Ca(2+). On the whole, this study demonstrates that glutamatergic vestibular synapse in the MVN can undergo NMDAR-dependent bidirectional plasticity and puts forward a new aspect for understanding the adaptive and compensatory plasticity of the oculomotor responses.

Optimal public rationing and price response

We study optimal public health care rationing and private sector price responses. Consumers differ in their wealth and illness severity (defined as treatment cost). Due to a limited budget, some consumers must be rationed. Rationed consumers may purchase from a monopolistic private market. We consider two information regimes. In the first, the public supplier rations consumers according to their wealth information (means testing). In equilibrium, the public supplier must ration both rich and poor consumers. Rationing some poor consumers implements price reduction in the private market. In the second information regime, the public supplier rations consumers according to consumers' wealth and cost information. In equilibrium, consumers are allocated the good if and only if their costs are below a threshold (cost effectiveness). Rationing based on cost results in higher equilibrium consumer surplus than rationing based on wealth.

Neural 17β-estradiol facilitates long-term potentiation in the hippocampal CA1 region

In the hippocampal formation many neuromodulators are possibly implied in the synaptic plasticity such as the long-term potentiation (LTP) induced by high-frequency stimulation (HFS) of afferent fibers. We investigated the involvement of locally synthesized neural 17β-estradiol (nE(2)) in the induction of HFS-LTP in hippocampal slices from male rats by stimulating the Schaffer collateral fibers and recording the evoked field excitatory postsynaptic potential (fEPSP) in the CA1 region. We demonstrated that either the blockade of nE(2) synthesis by the aromatase inhibitor letrozole, or the antagonism of E(2) receptors (ERs) by ICI 182,780 did not prevent the induction of HFS-LTP, but reduced its amplitude by ∼60%, without influencing its maintenance. Moreover, letrozole and ICI 182,780 did not affect the first short-term post-tetanic component of LTP and the paired-pulse facilitation (PPF). These findings demonstrate that nE(2) plays an important role in the induction phase of HFS-dependent LTP. Since the basal responses were not affected by the blocking agents, we suggest that the synthesis of nE(2) is induced or enhanced by HFS through aromatase activation. In this context, the local production of nE(2) seems to be a very effective mechanism to modulate the amplitude of LTP.

Long-term potentiation of synaptic response and intrinsic excitability in neurons of the rat medial vestibular nuclei

Using intracellular recordings, we investigated the effects of high frequency stimulation (HFS) of the primary vestibular afferents on the evoked excitatory postsynaptic potential (EPSP) and intrinsic excitability (IE) of type-A and type-B neurons of the medial vestibular nucleus (MVN), in male rat brainstem slices. HFS induces long-term potentiation (LTP) of both EPSP and IE, which may occur in combination or separately. Synaptic LTP is characterized by an increase in the amplitude, slope and decay time constant of EPSP and IE-LTP through enhancements of spontaneous and evoked neuron firing and of input resistance (Rin). Moreover, IE-LTP is associated with a decrease in action potential afterhyperpolarization (AHP) amplitude and an increase in interspike slope steepness (ISS). The more frequent effects of HFS are EPSP-LTP in type-B neurons and IE-LTP in type-A neurons. In addition, the development of EPSP-LTP is fast in type-B neurons but slow in type-A, whereas IE-LTP develops slowly in both types. We have demonstrated that activation of N-methyl-d aspartate receptors (NMDARs) is only required for EPSP-LTP induction, whereas metabotropic glutamate receptors type-1 (mGluR1) are necessary for IE-LTP induction as well as the full development and maintenance of EPSP-LTP. Taken together, these findings demonstrate that brief and intense activation of vestibular afferent input to the MVN neurons may provoke synaptic LTP and/or IE-LTP that, induced in combination or separately, may assure the different selectivity of the MVN neuron response enhancement to the afferent signals.

Influence of testosterone on synaptic transmission in the rat medial vestibular nuclei: estrogenic and androgenic effects

In brainstem slices of young male rat, we investigated the influence of the neuroactive steroid testosterone (T) on the synaptic responses by analyzing the field potential evoked in the medial vestibular nucleus (MVN) by vestibular afferent stimulation. T induced three distinct and independent long-term synaptic changes: fast long-lasting potentiation (fLP), slow long-lasting potentiation (sLP) and long-lasting depression (LD). The fLP was mediated by 17β-estradiol (E(2)) since it was abolished by blocking the estrogen receptors (ERs) or the enzyme converting T to E(2). Conversely, sLP and LD were mediated by 5α-dihydrotestosterone (DHT) since they were prevented by blocking the androgen receptors (ARs) or the enzyme converting T to DHT. Therefore, the synaptic effects of T were mediated by its androgenic or estrogenic metabolites. The pathways leading to estrogenic and androgenic conversion of T might be co-localized since, the occurrence of fLP under block of androgenic pathway, and that of sLP and LD under estrogenic block, were higher than those observed without blocks. In case of co-localization, the effect on synaptic transmission should depend on the prevailing enzymatic activity. We conclude that circulating and neuronal T can remarkably influence synaptic responses of the vestibular neurons in different and opposite ways, depending on its conversion to estrogenic or androgenic metabolites.

Effects of 17beta-estradiol on glutamate synaptic transmission and neuronal excitability in the rat medial vestibular nuclei

We investigated the effects of the neurosteroid 17beta-estradiol (E(2)) on the evoked and spontaneous activity of rat medial vestibular nucleus (MVN) neurons in brainstem slices. E(2) enhances the synaptic response to vestibular nerve stimulation in type B neurons and depresses the spontaneous discharge in both type A and B neurons. The amplitude of the field potential, as well as the excitatory post-synaptic potential (EPSP) and current (EPSC), in type B neurons, are enhanced by E(2). Both effects are long-term phenomena since they outlast the drug washout. The enhancement of synaptic response is mainly due to facilitation of glutamate release mediated by pre-synaptic N-methyl-D-aspartate receptors (NMDARs), since the reduction of paired pulse ratio (PPR) and the increase of miniature EPSC frequency after E(2) are abolished under D-(-)-2-amino-5-phosphonopentanoic acid (AP-5). E(2) also facilitates post-synaptic NMDARs, but it does not affect directly alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and group I-metabotropic glutamate receptors (mGluRs-I). In contrast, the depression of the spontaneous discharge of type A and type B neurons appears to depend on E(2) modulation of intrinsic ion conductances, as the effect remains after blockade of glutamate, GABA and glycine receptors (GlyRs). The net effect of E(2) is to enhance the signal-to-noise ratio of the synaptic response in type B neurons, relative to resting activity of all MVN neurons. These findings provide evidence for a novel potential mechanism to modulate the responsiveness of vestibular neurons to afferent inputs, and so regulate vestibular function in vivo.

ACP1 and offspring sex ratio in smoking puerperae: a study at population level

BACKGROUND

Data from previous study by our group suggest that in smoking women sex ratio of offspring is higher in newborns carrying ACP1C allele than in other ACP1 genotypes, suggesting that differences observed among human population concerning the effect of smoking may depend in part on this genetic factor.

OBJECTIVES

In order to further explore this issue we have studied another population and have analysed the relationship between sex ratio and ACP1C gene frequency at population level.

METHODS

The analysis includes 719 consecutive births from Central Italy considered in a previous paper and 5510 consecutive births from Sardinia. Data from English and Japanese populations have also been considered in the analysis.

RESULTS

Among newborns not carrying ACP1C there is a decrease of SR among the offspring of smoking mothers, while among newborns carrying the ACP1C allele there is an increase of SR among the offspring of smoking mothers relative to non-smoking mothers. Considering Sardinian, Italian, English and Japanese population there is a linear positive relationship between C allele frequency and SR in smoking mothers.

CONCLUSIONS

The present observation suggests an interaction between smoking and ACP1 regarding their effects on sex ratio, by which the presence of the ACP1C allele appears to counteract the effect of smoking. This suggests that genetic background may modify the effects of toxic environmental factors on gamete production and functionality and/or on intrauterine survival.

Rapid single tube genotyping of ACP1 by FRET based amplification and dual color melting curve analysis

Erythrocyte acid phosphatase (ACP1), also named low molecular weight phosphotyrosine phosphatase (LMW-PTP) is an enzyme involved in signal transduction pathways of tyrosine kinase receptor. The precise physiological role of ACP1 remains to be elucidated, however recent advancements suggest that it may play an important role in the control of cell proliferation. ACP1 is a highly polymorphic enzyme that has been investigated by case-control studies for decades. Initially based on protein electrophoresis, the phenotype of ACP1 is now detected by DNA-based techniques. Here, we report a new rapid single tube genotyping method for ACP1 by FRET based amplification and dual color melting curve analysis. This method does not require a post-procedure amplification process and allows unambiguous genotyping of 30 samples in less than 1 h.

Hydrophilic interaction liquid chromatography–APCI–mass spectrometry determination of 5-fluorouracil in plasma and tissues

A simple and fast analytical method using hydrophilic interaction liquid chromatography (HILIC) coupled with mass spectrometry was developed to analyse 5-fluorouracil (5-FU) in plasma and tissues. The HILIC system overcomes problems reported in obtaining satisfactory retention of 5-FU with other types of HPLC systems. After addition of internal standard (IS) (5-Chlorouracil (5-CU)), plasma proteins were precipitated with acetonitrile, and tissue samples homogenised with a micro-dismembrator. The analysis was performed using a polymer-based column (Ashaipak NH2) and the compounds were eluted under gradient conditions at 1 ml/min using a mobile phase containing a mixture of ammonium formate and acetonitrile. MS detection used a API 4000 mass spectrometry with heated nebulizer source and multiple reaction monitoring operated in the negative ion mode. The mass transitions of 5-FU and its internal standard were 129 m/z-->42m/z and 145 m/z-->42 m/z, respectively. The lower limits of quantitation in plasma and tissues were about 5 ng/ml and 10 ng/g, respectively, using 25 microl of plasma and 50mg of tissue. Good linearity, accuracy and precision were obtained in all matrices tested. The suitability and robustness of the method for in vivo samples were confirmed by analysis of mouse plasma, muscle and tumour from animals dosed with 5-FU.

Contribution of self-motion perception to acoustic target localization

CONCLUSION

The findings of this study suggest that acoustic spatial perception during head movement is achieved by the vestibular system, which is responsible for the correct dynamic of acoustic target pursuit.

OBJECTIVE

The ability to localize sounds in space during whole-body rotation relies on the auditory localization system, which recognizes the position of sound in a head-related frame, and on the sensory systems, namely the vestibular system, which perceive head and body movement. The aim of this study was to analyse the contribution of head motion cues to the spatial representation of acoustic targets in humans.

MATERIAL AND METHODS

Healthy subjects standing on a rotating platform in the dark were asked to pursue with a laser pointer an acoustic target which was horizontally rotated while the body was kept stationary or maintained stationary while the whole body was rotated. The contribution of head motion to the spatial acoustic representation could be inferred by comparing the gains and phases of the pursuit in the two experimental conditions when the frequency was varied.

RESULTS

During acoustic target rotation there was a reduction in the gain and an increase in the phase lag, while during whole-body rotations the gain tended to increase and the phase remained constant. The different contributions of the vestibular and acoustic systems were confirmed by analysing the acoustic pursuit during asymmetric body rotation. In this particular condition, in which self-motion perception gradually diminished, an increasing delay in target pursuit was observed.

Contribution of eye position to movement perception

OBJECTIVE

To investigate the influence of gaze eccentricity on movement perception during asymmetric vestibular stimulation.

MATERIAL AND METHODS

Subjects (n = 10) were placed on a rotating platform and oscillated asymmetrically in the dark. Subjects were asked to reproduce with a pointer the location in space of a light spot that was turned off at the beginning of the oscillation. The target was presented in centric and eccentric (0 degrees, 20 degrees and 40 degrees) positions.

RESULTS

In the centric position a large shift from the real position of the target was observed in the opposite direction to that of the faster vestibular stimulation. The shift increased when the target was placed eccentrically toward the slower vestibular stimulation side and decreased when it was placed in the opposite direction.

CONCLUSION

The dependence of rotation perception on the target position suggests that the eye deviation, imposed by the eccentricity of the target, is able to influence the perception of body movement and may modulate the internal reference frame.

Role of cerebellar nodulus and uvula on the vestibular quick phase spatial constancy

We investigated the orientation of quick phases (QPs) of vestibularly-induced eye movements in rabbits in response to "off-vertical" sinusoidal vestibular stimulation. We also examined the possible role of the cerebellar nodulus and ventral uvula in controlling QP spatial orientation and modification. During "off-vertical" vestibular stimulation QPs remained aligned with the earth's horizontal plane, while the slow phases (SPs) were aligned with the plane of vestibular stimulation. This suggests that QPs are coded in gravito-inertial coordinates and SPs in head coordinates. When rabbits were oscillated in the light (20 degrees peak-to-peak; 0.2 Hz) about an "off-vertical" axis for 2 h, the QPs changed their trajectory, abandoning the earth's horizontal plane to approach the plane of the stimulus. By contrast, in the absence of conjunctive optokinetic stimulation, QPs remained fixed in the earth's horizontal plane even after 2 h of "off-vertical" stimulation. The conjunctive combination of optokinetic and vestibular stimulation caused QPs to change their plane of rotation. After lesion of the nodulus-uvula the ability of rabbits to reorient QPs during conjoint vestibular-optokinetic stimulation was maintained. We conclude that the space orientation and adaptation of QPs do not require cerebellar control.

Different contributions of platelet-activating factor and nitric oxide in long-term potentiation of the rat medial vestibular nuclei

In rat brainstem slices, we investigated the differential role of nitric oxide (NO) and platelet-activating factor (PAF) in long-term potentiation (LTP) induced in the ventral portion of the medial vestibular nuclei (MVN) by high-frequency stimulation (HFS) of the primary vestibular afferents. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO) and the PAF receptor antagonist ginkgolide B (BN-52021) were administered before and after induction of potentiation. The effect of carboxy-PTIO was to completely prevent LTP. By contrast, BN-52021 only reduced the amplitude of HFS potentiation, which could develop fully at the drug washout or decline to zero, becoming a short-term phenomenon, in the case of long-lasting PAF receptor block. Both drugs, when given after HFS, had no effect on the already established potentiation, but whilst BN-52021 showed an influence within 5 min of the LTP induction, carboxy-PTIO did not affect the response once HFS was delivered. Moreover, we showed that the NO donor, sodium nitroprusside, and methylcarbamyl PAF (mc-PAF) induced LTP which was associated with an increase in glutamate release as shown by reduction in the paired-pulse facilitation ratio. The mc-PAF LTP was prevented by the NO scavenger, while NO LTP was only reduced by BN-52021. We suggest that NO and PAF are implicated as retrograde messengers in two different phases of vestibular LTP: NO in the induction phase; and PAF in the full expression phase.

Exogenous glutamate induces short and long-term potentiation in the rat medial vestibular nuclei

In rat brain stem slices, high concentrations of exogenous glutamate induce long-term potentiation (LTP) of the field potentials evoked in the medial vestibular nuclei (MVN) by vestibular afferent stimulation. At low concentrations, glutamate can also induce short-term potentiation (STP), indicating that LTP and STP are separate events depending on the level of glutamatergic synapse activation. LTP and STP are prevented by blocking NMDA receptors and nitric oxide (NO) synthesis. Conversely, blocking platelet-activating factor (PAF) and group I metabotropic glutamate receptors only prevents the full development of LTP. Moreover, in the presence of blocking agents, glutamate causes transient inhibition, suggesting that when potentiation is impeded, exogenous glutamate can activate presynaptic mechanisms that reduce glutamate release.

Synaptic plasticity in the medial vestibular nuclei: role of glutamate receptors and retrograde messengers in rat brainstem slices

The analysis of cellular-molecular events mediating synaptic plasticity within vestibular nuclei is an attempt to explain the mechanisms underlying vestibular plasticity phenomena. The present review is meant to illustrate the main results, obtained in vitro, on the mechanisms underlying long-term changes in synaptic strength within the medial vestibular nuclei. The synaptic plasticity phenomena taking place at the level of vestibular nuclei could be useful for adapting and consolidating the efficacy of vestibular neuron responsiveness to environmental requirements, as during visuo-vestibular recalibration and vestibular compensation. Following a general introduction on the most salient features of vestibular compensation and visuo-vestibular adaptation, which are two plastic events involving neuronal circuitry within the medial vestibular nuclei, the second and third sections describe the results from rat brainstem slice studies, demonstrating the possibility to induce long-term potentiation and depression in the medial vestibular nuclei, following high frequency stimulation of the primary vestibular afferents. In particular the mechanisms sustaining the induction and expression of vestibular long-term potentiation and depression, such as the role of various glutamate receptors and retrograde messengers have been described. The relevant role of the interaction between the platelet-activating factor, acting as a retrograde messenger, and the presynaptic metabotropic glutamate receptors, in determining the full expression of vestibular long-term potentiation is also underlined. In addition, the mechanisms involved in vestibular long-term potentiation have been compared with those leading to long-term potentiation in the hippocampus to emphasize the most significant differences emerging from vestibular studies. The fourth part, describes recent results demonstrating the essential role of nitric oxide, another retrograde messenger, in the induction of vestibular potentiation. Finally the fifth part suggests the possible functional significance of different action times of the two retrograde messengers and metabotropic glutamate receptors, which are involved in mediating the presynaptic mechanism sustaining vestibular long-term potentiation.

Role of nitric oxide in long-term potentiation of the rat medial vestibular nuclei

In rat brainstem slices, we investigated the role of nitric oxide in long-term potentiation induced in the ventral portion of the medial vestibular nuclei by high-frequency stimulation of the primary vestibular afferents. The nitric oxide scavenger [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide ] and the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester were administered before and after induction of potentiation. Both drugs completely prevented long-term potentiation, whereas they did not impede the potentiation build-up, or affect the already established potentiation. These results demonstrate that the induction, but not the maintenance of vestibular long-term potentiation, depends on the synthesis and release into the extracellular medium of nitric oxide. In addition, we analysed the effect of the nitric oxide donor sodium nitroprusside on vestibular responses. Sodium nitroprusside induced long-term potentiation, as evidenced through the field potential enhancement and unit peak latency decrease. This potentiation was impeded by D, L-2-amino-5-phosphonopentanoic acid, and was reduced under blockade of synaptosomal platelet-activating factor receptors by ginkgolide B and group I metabotropic glutamate receptors by (R,S)-1-aminoindan-1, 5-dicarboxylic acid. When reduced, potentiation fully developed following the washout of antagonist, demonstrating an involvement of platelet-activating factor and group I metabotropic glutamate receptors in its full development. Potentiation induced by sodium nitroprusside was also associated with a decrease in the paired-pulse facilitation ratio, which persisted under ginkgolide B, indicating that nitric oxide increases glutamate release independently of platelet-activating factor-mediated presynaptic events. We suggest that nitric oxide, released after the activation of N-methyl-D-aspartate receptors, acts as a retrograde messenger leading to an enhancement of glutamate release to a sufficient level for triggering potentiation. Once the synaptic efficacy has changed, it becomes a long-lasting phenomenon only through a subsequent action of platelet-activating factor.

Platelet-activating factor and group I metabotropic glutamate receptors interact for full development and maintenance of long-term potentiation in the rat medial vestibular nuclei

In rat brainstem slices, we investigated the interaction between platelet-activating factor and group I metabotropic glutamate receptors in mediating long-term potentiation within the medial vestibular nuclei. We analysed the N1 field potential wave evoked in the ventral portion of the medial vestibular nuclei by primary vestibular afferent stimulation. The group I metabotropic glutamate receptor antagonist, (R,S)-1-aminoindan-1,5-dicarboxylic acid, prevented long-term potentiation induced by a platelet-activating factor analogue [1-O-hexadecyl-2-O-(methylcarbamyl)-sn-glycero-3-phosphocholine], as well as the full development of potentiation, induced by high-frequency stimulation under the blocking agent for synaptosomal platelet-activating factor receptors (ginkolide B), at drug washout. However, potentiation directly induced by the group I glutamate metabotropic receptor agonist, (R,S)-3,5-dihydroxyphenylglycine, was reduced by ginkolide B. These findings suggest that platelet-activating factor, whether exogenous or released following potentiation induction, exerts its effect through presynaptic group I metabotropic glutamate receptors, mediating the increase of glutamate release. In addition, we found that this mechanism, which led to full potentiation through presynaptic group I metabotropic glutamate receptor activation, was inactivated soon after application of potentiation-inducing stimulus. In fact, the long-lasting block of the platelet-activating factor and metabotropic glutamate receptors prevented the full potentiation development and the induced potentiation progressively declined to null. Moreover, ginkolide B, given when high-frequency-dependent potentiation was established, only reduced it within 5 min after potentiation induction. We conclude that to fully develop vestibular long-term potentiation requires presynaptic events. Platelet-activating factor, released after the activation of postsynaptic mechanisms which induce potentiation, is necessary for coupling postsynaptic and presynaptic phenomena, through the activation of group I metabotropic glutamate receptors, and its action lasts only for a short period. If this coupling does not occur, a full and long-lasting potentiation cannot develop.

Effects of metabotropic glutamate receptor block on the synaptic transmission and plasticity in the rat medial vestibular nuclei

In rat brainstem slices, we investigated the possible role of metabotropic glutamate receptors in modulating the synaptic transmission within the medial vestibular nuclei, under basal and plasticity inducing conditions. We analysed the effect of the metabotropic glutamate receptor antagonist (R,S)-alpha-methyl-4-carboxyphenylglycine on the amplitude of the field potentials and latency of unitary potentials evoked in the ventral portion of the medial vestibular nuclei by primary vestibular afferent stimulation, and on the induction and maintenance of long-term potentiation, after high-frequency stimulation. Two effects were observed, consisting of a slight increase of the field potentials and reduction of unit latency during the drug infusion, and a further long-lasting development of these modifications after the drug wash-out. The long-term effect depended on N-methyl-D-aspartate receptor activation, as D,L-2-amino-5-phosphonopentanoic acid prevented its development. We suggest that (R,S)-alpha-methyl-4carboxyphenylglycine enhances the vestibular responses and induces N-methyl-D-aspartate-dependent long-term potentiation by increasing glutamate release, through the block of presynaptic metabotropic glutamate receptors which actively inhibit it. The block of these receptors was indirectly supported by the fact that the agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid reduced the vestibular responses and blocked the induction of long-term potentiation by high-frequency stimulation. The simultaneous block of metabotropic glutamate receptors facilitating synaptic plasticity, impedes the full expression of the long-term effect throughout the (R,S)-alpha-methyl-4-carboxyphenylglycine infusion. The involvement of such a facilitatory mechanism in the potentiation is supported by its reversible reduction following a second (R,S)-alpha-methyl-4-carboxyphenylglycine infusion. The drug also reduced the expression of potentiation induced by high-frequency stimulation. Conversely the electrical long-term potentiation was still induced, but it was occluded by the previous drug potentiation. We conclude that metabotropic glutamate receptors play a dual functional role in the medial vestibular nuclei, consisting in the inhibition of glutamate release under basal conditions, and the facilitation of N-methyl-D-aspartate-dependent plasticity phenomena.

Role of platelet-activating factor in long-term potentiation of the rat medial vestibular nuclei

In rat brain stem slices, we investigated the role of platelet activating factor (PAF) in long-term potentiation (LTP) induced in the ventral part of the medial vestibular nuclei (MVN) by high-frequency stimulation (HFS) of the primary vestibular afferent. The synaptosomal PAF receptor antagonist, BN-52021 was administered before and after HFS. BN-52021 did not modify the vestibular potentials under basal conditions, but it reduced the magnitude of potentiation induced by HFS, which completely developed after the drug wash-out. The same effect was obtained by using CV-62091, a more potent PAF antagonist at microsomal binding sites, but with concentrations higher than those of BN-52021. By contrast both BN-52021 and CV-6209 had no effect on the potentiation once induced. This demonstrates that PAF is involved in the induction but not in the maintenance of vestibular long-term effect through activation of synaptosomal PAF receptors. In addition, we analyzed the effect of the PAF analogue, 1-O-hexadecyl-2-O- (methylcarbamyl)-sn-glycero-3-phosphocoline (MC-PAF) and the inactive PAF metabolite, 1-O-hexadecyl-sn-glycero-3-phosphocoline (Lyso-PAF) on vestibular responses. Our results show that MC-PAF, but not Lyso-PAF induced potentiation. This potentiation was prevented by D,L-2-amino 5-phosphonopentanoic acid, suggesting an involvement of N-methyl-D-aspartate receptors. Furthermore, under BN-52021 and CV-6209, the MC-PAF potentiation was reduced or abolished. The dose-effect curve of MC-PAF showed a shift to the right greater under BN-52021 than under CV-6209, confirming the main dependence of MC-PAF potentiation on the activation of synaptosomal PAF receptors. Our results suggest that PAF can be released in the MVN after the activation of postsynaptic mechanisms triggering LTP, and it may act as a retrograde messenger which activates the presynaptic mechanisms facilitating synaptic plasticity.

Low-frequency stimulation cancels the high-frequency-induced long-lasting effects in the rat medial vestibular nuclei

In rat brainstem slices, we investigated the effects of low-frequency stimulation (LFS) of the primary vestibular afferents on the amplitude of the field potentials evoked in the medial vestibular nuclei (MVN). LFS induced long-term effects, the sign of which depended on whether the vestibular neurons were previously conditioned by HFS. In unconditioned slices, LFS evoked modifications of the responses that were similar to those observed after HFS but had a smaller extension. In fact, LFS caused long-lasting potentiation of the N1 wave in the MVN ventral portion (Vp) and long-lasting depression of the N2 wave in the MVN dorsal portion (Dp), whereas it provoked small and variable effects on the N1 wave. By contrast, when the synaptic transmission was already conditioned, LFS influenced the synaptic responses oppositely, reducing or annulling the HFS long-term effects. This phenomenon was specifically induced by LFS, because HFS was not able to cause it. The involvement of NMDA receptors in mediating the LFS long-term effects was supported by the fact that AP-5 prevented their induction. In addition, the annulment of HFS long-term effects by LFS was also demonstrated by the shift in the latency of the evoked unitary potentials after LFS. In conclusion, we suggest that the reduction of the previously induced conditioning could represent a cancellation mechanism, useful to quickly adapt the vestibular system to continuous different needs and to avoid saturation.