Unique cell adhesion and invasion properties of Yersinia enterocolitica O:3, the most frequent cause of human Yersiniosis

Many enteric pathogens are equipped with multiple cell adhesion factors which are important for host tissue colonization and virulence. Y. enterocolitica, a common food-borne pathogen with invasive properties, uses the surface proteins invasin and YadA for host cell binding and entry. In this study, we demonstrate unique cell adhesion and invasion properties of Y. enterocolitica serotype O:3 strains, the most frequent cause of human yersiniosis, and show that these differences are mainly attributable to variations affecting the function and expression of invasin in response to temperature. In contrast to other enteric Yersinia strains, invasin production in O:3 strains is constitutive and largely enhanced compared to other Y. enterocolitica serotypes, in which invA expression is temperature-regulated and significantly reduced at 37°C. Increase of invasin levels is caused by (i) an IS1667 insertion into the invA promoter region, which includes an additional promoter and RovA and H-NS binding sites, and (ii) a P98S substitution in the invA activator protein RovA rendering the regulator less susceptible to proteolysis. Both variations were shown to influence bacterial colonization in a murine infection model. Furthermore, we found that co-expression of YadA and down-regulation of the O-antigen at 37°C is required to allow efficient internalization by the InvA protein. We conclude that even small variations in the expression of virulence factors can provoke a major difference in the virulence properties of closely related pathogens which may confer better survival or a higher pathogenic potential in a certain host or host environment.

Monitoring of gene expression in bacteria during infections using an adaptable set of bioluminescent, fluorescent and colorigenic fusion vectors

A family of versatile promoter-probe plasmids for gene expression analysis was developed based on a modular expression plasmid system (pZ). The vectors contain different replicons with exchangeable antibiotic cassettes to allow compatibility and expression analysis on a low-, midi- and high-copy number basis. Suicide vector variants also permit chromosomal integration of the reporter fusion and stable vector derivatives can be used for in vivo or in situ expression studies under non-selective conditions. Transcriptional and translational fusions to the reporter genes gfp_mut3.1, amCyan, dsRed2, luxCDABE, phoA or lacZ can be constructed, and presence of identical multiple cloning sites in the vector system facilitates the interchange of promoters or reporter genes between the plasmids of the series. The promoter of the constitutively expressed gapA gene of Escherichia coli was included to obtain fluorescent and bioluminescent expression constructs. A combination of the plasmids allows simultaneous detection and gene expression analysis in individual bacteria, e.g. in bacterial communities or during mouse infections. To test our vector system, we analyzed and quantified expression of Yersinia pseudotuberculosis virulence genes under laboratory conditions, in association with cells and during the infection process.

Development of a progressive task regulation algorithm for robot-aided rehabilitation

Patient motivation is an important factor in rehabilitation. The difficulty level of the motor task, the awareness of the performance obtained, and the quantity and quality of feedbacks presented to the patient can influence patient motivation and produce different ways of acting and different performances. This study presents a Progressive Task Regulation algorithm able to evaluate the patient's performance during training and automatically change the features of the reaching movement, so as to adapt automatically the difficulty level of the motor task to the patient's ability. Use of the progressive task regulation algorithm should promote patient motivation throughout the course of treatment.

Lithium carbonate in amyotrophic lateral sclerosis: lack of efficacy in a dose-finding trial

BACKGROUND

A neuroprotective effect of lithium in amyotrophic lateral sclerosis (ALS) has been recently reported. We performed a multicenter trial with lithium carbonate to assess its tolerability, safety, and efficacy in patients with ALS, comparing 2 different target blood levels (0.4-0.8 mEq/L, therapeutic group [TG], vs 0.2-0.4 mEq/L, subtherapeutic group [STG]).

METHODS

The study was a multicenter, single-blind, randomized, dose-finding trial, conducted from May 2008 to November 2009 in 21 Italian ALS centers. The trial was registered with the public database of the Italian Agency for Drugs (http://oss-sper-clin.agenziafarmaco.it/) (EudraCT number 2008-001094-15).

RESULTS

As of October 2009, a total of 171 patients had been enrolled, 87 randomized to the TG and 84 to the STG. The interim data analysis, performed per protocol, showed that 117 patients (68.4%) discontinued the study because of death/tracheotomy/severe disability, adverse events (AEs)/serious AEs (SAEs), or lack of efficacy. The Data Monitoring Committee recommended stopping the trial on November 2, 2009.

CONCLUSIONS

Lithium was not well-tolerated in this cohort of patients with ALS, even at subtherapeutic doses. The 2 doses were equivalent in terms of survival/severe disability and functional data. The relatively high frequency of AEs/SAEs and the reduced tolerability of lithium raised serious doubts about its safety in ALS.

CLASSIFICATION OF EVIDENCE

The study provides Class II evidence that therapeutic (0.4-0.8 mEq/L) vs subtherapeutic (0.2-0.4 mEq/L) lithium carbonate did not differ in the primary outcome of efficacy (survival/loss of autonomy) in ALS. Both target levels led to dropouts in more than 30% of participants due to patient-perceived lack of efficacy and AEs.

Monocytes/macrophages and/or neutrophils are the target of IL-10 in the LPS endotoxemia model

IL-10 is a potent regulator of the innate and adaptive immune responses. Several cell types produce IL-10 and its receptor chains and these may regulate different immune responses. Here we report that inactivation of the IL-10 receptor (IL-10R1) gene in mice leads to an increased susceptibility to chemically induced colitis as in the classical IL-10-deficient mutant. To identify the cells regulated by IL-10 in immune responses, we generated several cell type specific IL-10R1-deficient mutants. We show that, in an IL-10-dependent LPS model of endotoxemia, dampening of the immune response requires expression of IL-10R1 in monocytes/macrophages and/or neutrophils but not in T cells nor B cells. As the macrophage and/or neutrophil-specific IL-10-deficient mutants also display the same phenotype, our results suggest that an autocrine loop in monocytes/macrophages is the most probable mechanism for the regulation of an LPS-induced septic shock. In contrast, in an IL-10-regulated T-cell response to Trichuris muris infection, IL-10 acting on T cells or monocytes/macrophages/neutrophils is not critical for the control of the infection.

Assessing mechanisms of recovery during robot-aided neurorehabilitation of the upper limb

OBJECTIVE

The present study aimed to qualify and quantify the different components of motor recovery in a group of stroke patients treated by robot-aided techniques. In addition, the learning model of each motor recovery component was analyzed.

METHODS

Two groups of poststroke patients were treated with the use of an elbow-shoulder manipulator, respectively, within (recent) and after (chronic) the first 6 months of their cerebrovascular accident. Both groups were evaluated by means of standard clinical assessment scales and a robot-measured evaluation method.

RESULTS

These findings confirm that motor training consisting of voluntary movements assisted by the robot device led to significant improvements in motor performance in terms of the kinematic and dynamic components of the arm movements. This corresponded to improvement of impairment as confirmed by the clinical scale results.

CONCLUSIONS

Knowledge of the recovery components and of the associated performance acquisition model may be useful in assessing and training stroke patients and should make it possible to precisely plan and, if necessary, modify the rehabilitation strategies.

Concurrent changes in shortening reaction latency and reaction time of forearm muscles in post-stroke patients

The objective was to confirm the hypothesis that shortening reaction (ShoRe), normally occurring on forcibly shortening a muscle, is depressed or delayed in post-stroke patients. Eight post-stroke patients and ten age-matched normal subjects had a 50 degrees wrist extension or flexion induced by a torque-motor in the affected and the non-affected upper limb. Patients were instructed either not to intervene or to assist displacement (reaction-time condition, RT). Frequency of occurrence and latency of stretch reflex (SR) and ShoRe, and RTs were measured from the electromyograms (EMG) of wrist flexor (FCR) and extensor (ECR) muscles. SR had higher than normal frequency in both muscles. ShoRe disappeared in ECR on the affected side but had normal frequency in FCR of both sides. ShoRe latency was prolonged in FCR and ECR, in both affected and unaffected sides. RTs were prolonged in both FCR and ECR, in both affected and unaffected sides. Across all patients, RTs and ShoRe latencies in the FCR were correlated. Neither RTs nor ShoRe latencies were correlated to Ashworth score. RTs were inversely correlated to Medical Research Council scores. The decreased and delayed ShoRe in post-stroke patients supports a role for the cortico-spinal pathway in its production or modulation. Monitoring of ShoRe can give insight into the recovery of the descending control of spinal reflexes.

Posterolateral instability of the elbow

The authors describe a rare case of recurrent posterior post-traumatic subdislocation of the elbow in a male aged 40 years. From a clinical point of view, it is a highly disabling condition, due to lesion of the ulnar portion of the radial collateral ligament. It is produced at minimum degrees of flexion movement in the elbow and depending on the entity of capsuloligamentous injury it may occur with episodes of instability, recurrent subdislocation or recurrent dislocation. Treatment is surgery and capsuloligamentous reconstruction according to the Osborne-Cotteril method, which has allowed for very satisfactory results to be obtained.

The shortening reaction of forearm muscles: the influence of central set

OBJECTIVE

The EMG of the forearm muscles shortened by an imposed wrist joint displacement has been studied at different levels and distribution of background muscle activity and with different instructions to the subjects, in order to test the hypothesis that the recorded EMG response (shortening reaction, ShoRe) could be deliberate in origin.

METHODS

Ten normal subjects were examined. A torque motor induced 50 degrees wrist extension or flexion at 500 degrees /s. The subjects were relaxed or exerted a 10% maximal voluntary contraction. They were instructed either not to intervene, or to oppose the displacement, or else to assist it. Several trials were repeated at different initial angles.

RESULTS

We found a short-latency reflex (SR) in the stretched muscle, be it flexor or extensor, and a later inconstant ShoRe in the antagonist. ShoRe latency was compatible with that of a reaction time (RT), and was not influenced by the initial wrist angle. When subjects assisted the movement, the EMG burst in the shortening muscle was in every respect a RT; when they opposed the movement, the ShoRe disappeared. There was a strict temporal relationship between SR duration and ShoRe latency.

CONCLUSIONS

We suggest that the brain would deliberately trigger the ShoRe on recognizing the displacement direction. The occurrence of such activity in the shortened muscle makes the SR to abruptly stop. The temporal relationship between the duration of the SR and onset of the ShoRe can be an expression of the inhibition on the SR burst by the cortical drive to the antagonist muscle being shortened, possibly through the action of spinal inhibitory interneurones. The ShoRe would complete the movement momentarily braked by the SR and redistribute the muscle tone across antagonists, appropriate for the new muscle length.

Loss of large-diameter spindle afferent fibres is not detrimental to the control of body sway during upright stance: evidence from neuropathy

Fifteen patients with Charcot-Marie-Tooth type 1A (CMT1A) disease and 46 normal controls were studied. In the patients, leg muscle strength, touch-pressure, vibration and joint position sense were reduced; lower limb tendon reflexes were absent in 12 or markedly decreased. Motor and sensory conduction velocity (CV) of leg nerves was either reduced or not measurable. The Neurological Disability Score and the Neuropathy Score were obtained from clinical and electrophysiological examination, respectively. Tilt of a supporting platform elicited short- (SLR) and medium-latency (MLR) responses to stretch in the foot muscle flexor digitorum brevis (FDB) in controls. In the patients, the former response was absent and the latter delayed. These findings are in keeping with the known loss of large-diameter myelinated fibres, with relative sparing of the smaller fibres. The MLR delay was fully accounted for by the slowed CV of the motor fibres. The MLR afferent time was similar to that in normal subjects. Body sway area (SA) during quiet stance was recorded with eyes open or closed, and with feet apart or together. Under all postural and visual conditions, SA was within normal range in the less severely affected patients, but was moderately increased in the patients with a more severe neuropathy score. Across all patients, no correlation was found between SA and muscle force, motor CV, touch pressure, vibration and joint position sense, considered either separately or as an aggregate. We suggest that: (1) functional integrity of the largest afferent fibres is not necessary for appropriate equilibrium control during quiet stance and (2) any unsteadiness is related to additional functional alterations in smaller fibres, most likely group II spindle afferent fibres.

Transcranial magnetic stimulation and silent period in spasmodic torticollis

OBJECTIVE

Our objective was to study the corticobulbar projections to neck muscles in cervical dystonia.

DESIGN

We compared both the motor evoked potentials and the electromyographic silent period after transcranial magnetic stimulation from sternocleidomastoid and trapezius muscles in a group of 13 patients with spasmodic torticollis with those of 20 healthy volunteers.

RESULTS

With the target muscle at rest, no changes of motor threshold, motor evoked potentials latency, and amplitude were observed in dystonic patients. With facilitation, the mean amplitude of the motor evoked potentials was increased in patients compared with controls, the significant difference being for the trapezius muscle, whereas the latency did not differ between groups. The cortical silent period was significantly shorter in dystonic patients than in healthy subjects in both muscles. The duration of the cortical silent period recorded from the sternocleidomastoid muscle showed a positive correlation with the degree of neurologic disability assessed by Tsui's scale. No abnormalities of both nerve conduction velocity and peripheral silent period by stimulation of accessory nerve were found.

CONCLUSIONS

These results indicate an impairment of the mechanisms of inhibitory motor control in patients with spasmodic torticollis, which could be the result of a decrease of the basal ganglia inhibitory output over the motor cortex.

Quantitative measures of spasticity in post-stroke patients

OBJECTIVE

Quantitative evaluation of muscle tone in post-stroke patients; correlation of biomechanical indices with conventional clinical scales and neurophysiological measures; characterization of passive and neural components of muscle tone.

METHODS

Mechanical stretches of the wrist flexor muscles of 53 post-stroke patients were imposed by means of a torque motor at constant speed. Patients were clinically studied using the Ashworth scale for spasticity and the Medical Research Council score for residual muscle strength. The neurophysiological measures were Hoffmann reflex latency, Hmax/Mmax ratio, stretch reflex threshold speed (SRTS), stretch reflex (SR) latency and area, passive (ISI) and total (TSI) stiffness indices.

RESULTS

Hmax/Mmax ratio, SR area, ISI and TSI values were significantly higher in patients, while SRTS was significantly lower. TSI, SRTS and SR area were highly correlated to the Ashworth score.

CONCLUSIONS

This EMG-biomechanical technique allows an objective evaluation of changes in muscle tone in post-stroke patients, providing easily measurable, quantitative indices of muscle stiffness. The linear distribution of these measures is particularly indicated for monitoring changes induced by treatment. The apparatus seems suitable to characterize neural stiffness, while difficulties were found in isolating the passive components, because of the occurrence of tonic EMG activity in most spastic patients.

Motor neuron disease: usefulness of transcranial magnetic stimulation in improving the diagnosis

Clinical upper motor neuron (UMN) involvement is sometimes difficult to detect in motor neuron disease (MND). For this reason we performed transcranial magnetic stimulation (TMS) to find out whether this technique may be useful in revealing signs of pyramidal tract impairment. Fifty-five MND patients, clinically divided into 22 amyotrophic lateral sclerosis (ALS), 18 ALS with probable UMN signs (ALS-PUMNS), 10 pure lower motor neuron syndrome (LMNS), and 5 progressive bulbar palsy (PBP), underwent standard TMS, recording from abductor digiti minimi and flexor allucis muscles. Prolongation of cortical motor evoked potential (MEP) latency and central conduction time (CCT) and absent MEP were considered as pathologic. ALS-PUMNS and LMNS patients were clinically reclassified after 1 year. TMS was abnormal in 95.4% of ALS, 72.2% of ALS-PUMNS, 50% of LMNS and 20% of PBP. Correlations between TMS parameters and both clinical signs of UMN involvement and disease severity were highly significant. TMS showed a high sensitivity, but lacked specificity. After 1 year, 11 patients among the ALS-PUMNS group were clinically reclassified as definite ALS: all of them had shown TMS abnormalities at the first examination. In conclusion, TMS provides important diagnostic information for an early prediction of ALS in those MND patients presenting with clinically equivocal UMN impairment.

Somatosensory and motor evoked potentials at different stages of recovery from severe traumatic brain injury

OBJECTIVE

To detect changes of somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) at different stages of recovery from severe brain injury and to determine whether they can be used to predict late functional outcome.

DESIGN

Correlational study on a prospective cohort.

SETTING

Brain injury rehabilitation center.

PATIENTS

Twenty-seven consecutively sampled patients with severe traumatic brain injury referred to the inpatient intensive rehabilitation unit of primary care in a university-based system.

MAIN OUTCOME MEASURES

(1) Glasgow Outcome Scale, Disability Rating Scale, and Functional Independence Measure; (2) SEPs and MEPs from upper limbs (ULs) and lower limbs (LLs). Outcome was assessed at 6 and 12 months after trauma. Correlations were computed with the nonparametric test of Spearman-Rank.

RESULTS

Both SEPs and MEPs showed dynamic changes (p < .02 for N20, p < .05 for N30, P40, and N45), with a trend toward a progressive normalization. N30 was more frequently abnormal than N20. SEPs from LLs were more frequently and more persistently abnormal than those from ULs. Clinical and functional outcome was strongly correlated with the degree of abnormality of SEPs from LLs (p < .002), whereas only mild relationships were found with SEPs from ULs. Both SEPs and MEPs showed a high negative predictive value (83% for N30 and 83% for P40), but only SEPs from LLs also had a high positive predictive value (72% for P40). Sensitivity was 88% both for N30 and P40. Specificity was 50% for N30 and 70% for P40).

CONCLUSION

SEPs from LLs can be very useful in monitoring the postacute phase of traumatic brain injury and in identifying patients who require further intensive rehabilitation. MEPs may be of questionable value.

Sympathetic skin response in amyotrophic lateral sclerosis

OBJECTIVES

The aim of our study was to verify the usefulness of the sympathetic skin response (SSR) as an instrument for assessing autonomic involvement in amyotrophic lateral sclerosis (ALS).

MATERIAL AND METHODS

- We studied palmar and plantar SSR in 31 patients with ALS (mean age: 58.4+/-9.3 years); 48 age-matched healthy subjects constituted the control group.

RESULTS

Palmar SSR was elicitable in all patients, and its latency and amplitude did not significantly differ from that of the controls. Plantar response was evoked in all but 7 patients. The lack of response was significantly related to the functional disability and duration of the disease.

CONCLUSIONS

We conclude that SSR, even the plantar response, cannot be considered a useful tool for detecting early autonomic involvement in ALS.

[Processes of speech production: Analysis of the methods and applications in a group of normal subjects (I)]

The measurement of reaction times in response to suitable stimuli may provide insight into the separate functional blocks corresponding to diverse speech production mechanisms. The quantitative evaluation of speech motor performance provides useful information for the early detection and long-term monitoring of many neurological diseases. The vocal reaction times (VRTs) technique and its application in the assessment of a group of normal subjects is presented. Speech motor performance and the effect of age were investigated by measuring VRTs and speech duration, in a group of thirty normal subjects divided into three age groups (18-44, 45-59, 60-80). VRTs were measured by using an immediate and delayed reaction stimulation paradigm. Analysis of the acoustic and electromyographic signals indicated that reaction times increased with age in both the immediate and delayed tasks; also the acoustic signal durations increased with age. The analysis of variance showed that the difference between the young and elderly groups was statistically significant. This technique may be considered a useful tool to provide qualitative and quantitative measures of the processes involved in speech production.

Quantitative evaluation of normal muscle tone

Forty-eight normal subjects were evaluated for the purpose of objectively quantifying muscle tone. Flexor carpi radialis and extensor digitorum communis electromyographic (EMG) activity was simultaneously recorded during wrist movements imposed by a torque motor. Each session was subdivided into three steps: (1) measurement of the 'intrinsic stiffness index' (ISI) at 10 degrees/s; (2) measurement of the 'total stiffness index' (TSI) at 500 degrees/s; (3) evaluation of the stretch reflex threshold speed (SRTS). No stretch reflex (SR) was found in about half of the subjects, even at the highest speed. ISI was higher in males (p < 0.001); significant differences in TSI were found between subjects with SR and those without (p < 0.02); no statistical differences in SRTS were found for either age or gender. ISI, TSI and SRTS, appear to be reliable indices of the range of normal muscle tone for its quantitative assessment.

[Effect of motor neuron density on the curve of motor neuron impoverishment in amyotrophic lateral sclerosis]

We have clinically and electromyographically examined, during a follow-up study, weakened muscles and still clinically normal muscles of 9 patients affected by amyotrophic lateral sclerosis (ALS) and of 3 patients affected by focal benign amyotrophy (FBA). MRC scores corrected with positive semiquantitative evaluations of the number of giant motor unit (MU) action potentials and with negative evaluations of the number of fasciculations and fibrillations potentials have been found to linearly correlate with the percentage of the residual MUs calculated from the mean amplitude and the spike number during maximal voluntary contraction. A main finding is that the loss of MUs slows down in the last 10 months of the disease. It follows that after a phase when the pathological process was accelerated by the toxic effect due to the abnormally high concentration of glutamate released by dead motoneurons, the residual cells because of the decreased motoneuronal density are less exposed to the possible neurotoxic damage.

Decreased heart rate variability in amyotrophic lateral sclerosis

Autoregressive spectral analysis of heart rate variability (HRV) was performed in 29 patients with amyotrophic lateral sclerosis (ALS) and 33 age-matched healthy subjects to evaluate the involvement of the autonomic nervous system. HRV analysis provides a means to recognize low (LF) and high (HF) frequency components, respectively mediated by sympathetic and parasympathetic heart control. An increase in the mean heart rate at rest (P < 0.001), a decrease in standard deviation of R-R interval as well as in PNN50 (P < 0.001), and an increase in the LF/HF component ratio (P < 0.01) were found in the ALS patients, indicating a vagal-sympathetic imbalance. These alterations were not related to the clinical features and to the duration of the disease. Our results suggest a subclinical involvement of the autonomic nervous system in ALS, particularly affecting parasympathetic cardiovascular control.

[Abdominal propriospinal myoclonus of unknown etiology]

We report the case of a 77-year-old woman with a two-year history of abdominal non rhythmic myoclonus. Neurological examination was normal. Bursts of myoclonic activity were recorded from the rectus abdominis muscle and then from the external oblique muscle after a delay of 40 ms. Magnetic resonance imaging of dorsal spine revealed T7-T8 and T9-T10 disc protrusions without root compression. Electroencephalography, back-averaging-EEG, brain computed tomography scan, motor and sensory evoked potentials revealed no abnormality, thus ruling out the possibility that the myoclonic jerks might be of cortical origin. Electromyography of the rectus abdominis and external oblique and of the T7-T8 paraspinal muscles did not show signs of denervation. Therefore a peripheral origin of the myoclonus could be excluded. In our patient the difference in latency of the EMG activity between the external oblique and the rectus abdominis muscles was possibly due to the caudal propagation of the myoclonus by slowly conducting pathways, supporting the hypothesis for its propriospinal origin, even though a known ethiologic factor could not be identified.

Multiparametric quantitative evaluation of the speech production system: a study in normal subjects

This paper describes a systems architecture developed for the study of the speech production system. The architecture utilizes two personal computers: the "Word-Image Presenter" (WIP) that presents a sequence of words to the subject under examination as visual stimulation, and the "Signal Acquisition System" that controls the WIP, acquires the acoustic signal, the oromandibular electromyographic signals, the kinematic lip and jaw signals and measures reaction times and durations. Thirty normal subjects divided into three age groups (18-44, 45-59, 60-80) underwent examination by means of the described system. During the test a random sequence of two words was presented to the subjects; the protocol consisted of an immediate reading task and two delayed reading tasks with variable foreperiods of 0.1 and 1.5 s for one task and 0.5 and 4 s for the other. The analysis of the resultant acoustic and electromyographic signals indicated that reaction times increased with age in both the immediate and delayed tasks. The analysis of variance showed that the difference between the young and elderly groups was statistically significant. The sample size of the groups, however, is too small to consider these results normative data.

[The clinical assessment and intensive treatment of meningoencephalitis in newborns and children of subsequent ages]

We focused on the best timing and management when admitting into intensive care unit a pediatric patient with central nervous system infection. The modified scales for pediatric patients did not prove satisfactory and reliable for making such decision. In fact the final score is obtained by adding the partial scores regarding the different clinical aspects. That bears a loss of informations. For this reason we think that the cardiorespiratory and metabolic parameters, assessed in a period of time, may indicate the moment when it is necessary to start an intensive care in these patients, regardless of consciousness. We therefore discussed the monitoring precociously required in these patients after assessing the initial clinical status. We also discussed the intensive care procedure employed in severely ill patients with cardio-circulatory and metabolic problems due to septic shock caused by bacterial meningoencephalitis (infants) and meningitis (other pediatric ages). In patients affected by infectious or post-infective encephalitis with respiratory failure and/or brain edema, it is essential to apply the organ protection procedures and particularly neuroprotection.

Deblocking effect of TRH-T in three cases of chronic progressive multifocal neuropathy

Three cases of acquired demyelinating multifocal neuropathy with persistent conduction blocks are reported. In one of them protyreline tartrate (TRH-T) had an evident deblocking effect; similar but milder effects were seen in the other two cases. The course and consistency of this effect is analyzed on the grounds of clinical and electromyographic findings. The nature of the THR-T responsive conduction block is analysed as a mild variant of CIDP with regard to its occurrence in a late and chronic phase without signs of active immune processes.

[Serum levels of IgG subclasses in critically ill premature infants treated with intravenous immunoglobulins]

Fifty eight premature infants, all needing intensive care and mechanical ventilation, were randomly allocated to two groups. Intravenous immunoglobulins (IVIG, 500 mg/kg Sandoglobulin) were administered to Group 1 while Group 2 received saline as placebo. IgG subclass serum levels were evaluated in both groups on admission, after two hours from the end of IVIG or saline infusion and from day 3 to 7 from birth. IgG subclasses were also measured in 10 healthy term neonates during the first day of life. Results show that after 2 hours from the end of IVIG administration all IgG subclasses reach levels comparable to term neonates. Comparing IgG values between treated and untreated preterm neonates it was observed that on day 3 only IgG1 and IgG3 subclasses were significantly higher in Group 1 than in Group 2. At day 5 no differences were observed between the two groups. IgG2 subclass rose reaching a significant difference between the two groups ad day 5 and 7. Our data show that IVIG single dose (500 mg/kg) administration doesn't produce a constant elevation in all IgG subclasses during the first week of life in the critically ill preterm infant.

EMG evaluation of motor neuron sprouting in amyotrophic lateral sclerosis

Collateral sprouting has been evaluated in amyotrophic lateral sclerosis (ALS) patients on the basis of: 1) Motor Unit action potential (M.U.A.P.) parameters evaluated by simultaneous EMG recordings using concentric needle electrodes and surface electrodes and 2) Motor Action Potential (M.A.P.) activated by graded electrical stimulation of nerve and recorded with the same electrodes. Mean values of duration and amplitude were calculated in 40 normal age-matched controls, 42 ALS patients in the early phase of the disease and in 5 muscles of three ALS patients during the whole course of the disease including the last paralytic phase. Percentage of M.U.A.P.s with linked potentials and highest amplitude was also calculated. The study confirms previous suggestions on collateral sprouting occurring in the early, middle and advanced phases of the disease and it shows, at variance with some recent claims, that it fails in the latest phase of paralysis.

[Nosocomial infections caused by methicillin-resistant Staphylococcus aureus in a pediatric intensive care unit]

We performed an epidemiological investigation owing to the appearance between February and March 1988, of subsequent MRSA infections in our ICU; we also started a checking scheme. At the same time we performed a retrospective-perspective study of 701 patients (310 newborns 391 not newborns) admitted into ICU from 1-1-1987 to 30-6-1988. This study allowed us to settle the presence of MRSA in ICU and the manner in which they become infected. From our study the 4.9% of our patients contracted hospital infections and the 34.2% of these were MRSA infections. The 39.7% of our colonized patients were MRSA. It is really significant the frequency of MRSA colonization (p less than 0.0005) among newborn patients compared with other age patients; in the meantime there is not statistical significance in the frequency of MRSA hospital infections among the two groups. The results of our study show that infections were probably transmitted by the hands of the members of staff and that the reservoir of MRSA are tracheostomized hosts or long term ventilated patients.

Ataxia in myxoedema: a neurophysiological reassessment

In a long-standing case of myxoedema with ataxia and dysarthria, neurophysiological investigations were carried out to assess how much of the ataxic dysbasic syndrome depended on the slowness of mechanical contraction and how much resulted from primary cerebellar involvement. It was observed that the Achilles reflexogram showed a marked prolongation of contraction and relaxation time and that in both quadriceps and triceps surae mechanical percussion induced a marked myxoedema and prolonged relaxation time. The EMG of these muscles during voluntary contraction and stopping reaction detected an excessive recruitment of the antagonistic muscles, starting without any abnormal delay, a finding at variance with a typical cerebellar pattern. Post-urographic analysis gave a pattern of oscillations still within the normal range. These findings suggest that the gait alterations of our patient depended on the increase in muscle contraction time and the consequent excessive recruitment of the antagonists.

[Apple peel small bowel: surgical correction and post-operative treatment]

The authors describe 6 cases of Apple Peel Small Bowel observed in the last ten year experience in Institute G. Gaslini of Genoa, Italy. They make a precision on early diagnosis and on surgical treatment, which is original, and also on post-operatory medical treatment. The importance of making an optimal nutritional support with total and partial parenteral nutrition for long time is of great significance to have a better outcome and psycho-physical development in such patients.

The identification of neuroapraxia, axonostenosis and trigger zone in facial nerve pathology

The classical electromyographic investigations and simultaneous recordings of voluntary activity and M responses from muscles of both the upper and lower branch of the facial nerve were carried out in 5 patients with Bell's palsy. R1 responses were also recorded. All investigations were extended to the healthy side. With the aim of localizing the point of axonostenosis with axonal atrophy we investigated the following parameters: conduction velocity (c.v.) in the fallopian canal, c.v. in the external facial nerve, side difference of R1-M. In one case of amyotrophic lateral sclerosis with previous Bell's palsy signs of collateral sprouting and of ephaptic transmission were detected.

Subcapital fractures of the femur. Treatment by reduction and fixation and 3 spongy bone screws

The authors reviewed 21 cases of subcapital fracture of the femur treated by reduction and fixation with 3 spongy bone screws (AO type) between 1980 and 1983. There were 4 failures (2 non-union and 2 ischaemic necrosis, one definite and one suspected). In all patients with a reasonable life expectancy the treatment should be reduction and fixation, but the technique must be extremely accurate. If open reduction is necessary to ensure perfect reduction, it must be by the anterior route so as not to inflict further damage on the blood supply. Fixation must be rigid and sustained. This can be best achieved by using 3 screws of the AO spongy type which also ensures a degree of compression which enhances consolidation.