Effects of alfaxalone, propofol and isoflurane on cerebral blood flow and cerebrovascular reactivity to carbon dioxide in dogs: A pilot study

Propofol total intravenous anesthesia is a common choice to anesthetize patients with increased intracranial pressure, reducing cerebral blood flow while maintaining cerebrovascular reactivity to CO2. Propofol and alfaxalone are commonly used for total intravenous anesthesia in dogs, but the effects of alfaxalone on cerebral blood flow and cerebrovascular reactivity to CO2 are unknown. Our hypothesis was that alfaxalone would not be significantly different to propofol, while isoflurane would increase cerebral blood flow and decrease cerebrovascular reactivity to CO2. Six healthy hound dogs were evaluated in this randomized crossover trial. Dogs were anesthetized with 7.5 mg/kg propofol, 3 mg/kg alfaxalone or 8 % sevoflurane, mechanically ventilated and maintained with propofol (400 µg/kg/min), alfaxalone (150 µg/kg/min) or 1.7 % end-tidal isoflurane, respectively, with one week washout between treatments. Cerebral blood flow and cerebrovascular reactivity to CO2 during hypercapnic and hypocapnic challenges were measured using arterial spin labelling and blood oxygen level-dependent magnetic resonance imaging sequences, respectively. Median (interquartile range, IQR) normocapnic cerebral blood flow was significantly lower (P = 0.016) with alfaxalone compared to isoflurane, in the whole brain 15.39 mL/min/100 g (14.90-19.90 mL/min/100 g) vs. 34.10 mL/min/100 g (33.35-43.17 mL/min/100 g), the grey matter 14.57 mL/min/100 g (13.66-18.72 mL/min/100 g) vs. 32.37 mL/min/100 g (31.03-42.99 mL/min/100 g), the caudal brain 15.47 mL/min/100 g (13.37-21.45 mL/min/100 g) vs. 36.85 mL/min/100 g (32.50-47.18 mL/min/100 g) and the temporal lobe grey matter 18.80 mL/min/100 g (15.89-20.84 mL/min/100 g) vs. 43.32 (36.07-43.58 mL/min/100 g). Median (IQR) hypocapnic cerebrovascular reactivity to CO2 was significantly higher (P = 0.016) for alfaxalone compared to isoflurane 8.85 %S/mm Hg (6.92-10.44 %S/mm Hg) vs. 3.90 %S/mm Hg (3.80-4.33 %S/mm Hg). Alfaxalone maintained lower cerebral blood flow and higher hypocapnic cerebrovascular reactivity to CO2 than isoflurane.

Multidisciplinary early intervention in Down syndrome: a retrospective study

BACKGROUND

Scientific community agrees on the importance of early, global multidisciplinary family-based care in the neuropsychological development of children with disabilities, including those with Down Syndrome (DS). This study aim to assess whether a structured, multidisciplinary early intervention carried out at the outpatient service of Stella Maris I.R.C.C.S. can lead to better outcomes in children with DS, in development and cognitive functioning, compared to conventional care provided by the local health centres (ASL).

METHODS

We included in the study 20 children with DS. The experimental group received early treatment (0-36 months), while the control group only underwent cognitive assessments. In order to examine the outcome of long-term cognitive functioning, our study evaluated assessments of the children at 5 years of age, by administering the WPPSI-III scale.

RESULTS

In our result we can confirm the typical profile of children with Down Syndrome described in the literature. Comparing the results obtained in both groups, we see that the mean scores obtained by the experimental group, in all three of the quotients examined, are higher than the mean scores obtained by the control group.

CONCLUSIONS

This study makes it clear that early, structured, multidisciplinary interventions play a fundamental role in modifying neurocognitive outcomes in children with Down Syndrome. The results of this study thus confirm the usefulness of the outpatient service in the early management of individuals with DS, following a multidisciplinary, structured pathway focused on the child and his/her family.

Toward the Knowledge of the Epidemiological Impact of Acute Rheumatic Fever in Italy

Background: To estimate the incidence of Acute Rheumatic Fever (ARF) in Tuscany, a region of Central Italy, evaluating the epidemiological impact of the new diagnostic guidelines, and to analyse our outcomes in the context of the Italian overview. Methods: A multicenter and retrospective study was conducted involving children <18 years old living in Tuscany and diagnosed in the period between 2010 and 2019. Two groups were established based on the new diagnostic criteria: High-Risk (HR) group patients, n = 29 and Low-Risk group patients, n = 96. Results: ARF annual incidence ranged from 0.91 to 7.33 out of 100,000 children in the analyzed period, with peak of incidence registered in 2019. The application of HR criteria led to an increase of ARF diagnosis of 30%. Among the overall cohort joint involvement was the most represented criteria (68%), followed by carditis (58%). High prevalence of subclinical carditis was observed (59%). Conclusions: Tuscany should be considered an HR geographic area and HR criteria should be used for ARF diagnosis in this region.

Author Correction: Forearc carbon sink reduces long-term volatile recycling into the mantle

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

P657Anticoagulation strategies based on warfarin or direct oral anticoagulants compared to major hemorrhagic events: the relevance of patients aged 75 years or older

Objective

To evaluate rates of major bleeding (mBleed) associated with anticoagulant treatments in patients (pts) with age ≥75 years (y), referred to hospital in northwest Tuscany.

Methods

We analysed 4-y survey; 302,687 visits; catchment area 197,722 inhabitants, of whom 15,267 on Warfarin (W) and 10,397 on direct oral anticoagulants (DOACs). DOACs were available in the catchment area since 4 y (dabigatran and rivaroxaban), 3 y (apixaban), and 2 y (edoxaban). Overall, 3,373 pts received dabigatran, 4,046 rivaroxaban, 2,141 apixaban, and 839 edoxaban. Pts with hemorrhage were submitted to propensity score matching for mBleed and stratified according to age ≥75 y, and W or DOACs. Primary endpoint was one-month death in pts with age ≥75 y.

Results

Out of 1,919 mBleed enrolled, those of pts aged ≥75 y were 1,127 (59%) versus (vs) 792 (41%) aged <75 y, with 77 (4.0%) one-month death vs 20 (1.0%), respectively; p<0.0001.

Patients on W showed higher rate of mBleed (n=175; 9.1%) compared to DOACs (n=53; 2.8%); p<0.0001. One-month death accounted for 14 (0.7%) vs 1 (0.1%), respectively; p=0.0019. Pts aged ≥75 years were more likely to show female gender and comorbidities including atrial fibrillation; p<0.01. Among DOACs, edoxaban presented the lowest absolute rate of hospital admission for mBleed and dabigatran the highest, although without statistical differences within DOACs (p=0.6454). Interestingly, in the subset of pts aged ≥75 y, within DOACs, we found no statistical difference in one-month mortality, although edoxaban showed one death due to brain mBleed; conversely, we found statistical significance in rate of mBleed. Indeed, edoxaban vs dabigatran showed p=0.0008, edoxaban vs apixaban p=0.0242, edoxaban vs rivaroxaban p=0.0058, apixaban vs rivaroxaban p=0.7093, apixaban vs dabigatran p=0.2279, rivaroxaban vs dabigatran p=0.5087.

Warfarin or DOACs and outcomes Major Bleeding (pts ≥75 y) p value versus pts <75 y p value within group One-month death (pts ≥75 y) p value versus pts <75 y p value within group n=1,127 n=77 Warfarin 175 (9.1%) 0.0001 <0.0001 14 (1.2%) 0.514 0.0019 DOACS 53 (2.8%) 0.0001 1 (0.1%) 0.256 Dabigatran 21 (1.1%) 0.026 0.0088 0 (0%) 0.391 0.8012 Rivaroxaban 16 (0.8%) 0.121 0 (0%) 0.619 Apixaban 13 (0.7%) 0.033 0 (0%) 1 Edoxaban 3 (0.2%) 0.647 1 (0.1%) 0.191 Patients: pts; direct oral anticoagulants: DOACs; p value Yates' correction: p value.

Patients with age >75 years and bleeding

Conclusion

In pts with age ≥75 y, rate of mBleed and short-term mortality were significantly higher than in pts aged <75 y In those pts, DOACs showed significantly lower rate of mBleed, and short-term death. Within DOACs, edoxaban was more likely to show lower rate of mBleed.

P4636Major gastrointestinal haemorrhage of patients with ongoing anticoagulants presented to the emergency department of a community hospital: four-year survey

Objective

To look for outcomes of patients (pts) with major gastrointestinal haemorrhage (mGIH) and ongoing anticoagulants out of four-year survey of community hospital with catchment area 197,722 inhabitants, of whom 15,267 with Warfarin (W) and 10,397 with direct oral anticoagulants (DOACs). DOACs were available for prescription in the catchment area since 4 years (dabigatran and rivaroxaban), 3 years (apixaban), and 2 years (edoxaban).

Methods

Haemorrhage (n=1,919) were submitted to propensity score matching for major bleeding; mGIH were enrolled and stratified according to ongoing W or DOACs. Primary endpoint was one-month death.

Results

Out of 476 mGIH, 73 pts received anticoagulants; 22 DOACs and 51 W; p=0.0006. Of note mGIH on W accounted for 2.7% (51/1,919) per year of pts, and 0.08% (51/15,267) of the catchment area. Conversely, mGIH on DOACs accounted as follows: dabigatran (n=10/476) 0.53%, rivaroxaban (n=6/476) 0.32%, apixaban (n=5/476) 0.35%, and edoxaban (n=1/476) 0.11% per year of pts; p=0.117. Rate of mGIH and DOACs versus (vs) rate of mGIH and W as follows: less than (−) 5 fold (2.7x100/0.53) of dabigatran vs W, p=0.004; −8 fold (2.7x100/0.32) of rivaroxaban vs W, p=0.0002; −7 fold (2.7x100/0.35) of apixaban vs W; p=0.ehz745.10188, and −25 fold (2.7x100/0.11) of edoxaban vs W; p=0.ehz745.101801. However no difference versus the catchment area per year (0.723): 0.07% (10/3,373) dabigatran, 0.04% (6/4,046) rivaroxaban, 0.08% (5/2,141) apixaban, 0.06% (1/839) edoxaban.

Overall, one-month death accounted for 10/476 (2.1%). Of note 236 mGI were from the upper tract and 240 from the lower tract. Among upper tract, 10 pts received DOACs (4 dabigatran, 4 rivaroxaban, 2 apixaban, and 0 edoxaban) and 21 received W. One-month death was 0/10 DOACs versus 1/21 W, p=0.483. Among lower tract, 12 pts received DOACs (6 dabigatran, 2 rivaroxaban, 3 apixaban, and 1 edoxaban) and 30 pts received W; one-month death was 0 for every groop. Anticoagulant reversal treatment was given to 6/22 (27%) pts with DOACs versus 18/51 (35%) with W, p=0.014; transfusion to 6/22 (27%) versus 11/51 (22%), respectively, p=0.306; admission 19/22 (86%) versus 42/51 (82%), respectively, p=0.004. Sensitivity/specificity ratio of variables and biomarkers for aggressive pharmacological approach were obtained by area under ROC curve (AUC) >0.50. PTT value >37 sec (AUC 0.57) showed sensitivity 15%, specificity 90%; INR value >1.4 (0.50), sens 15%, spec 80%. In addition, warfarin (0.49) sens 15%, spec 80%; age ≥75 years (0.48) sen 60%, spec 40%.

Gastrointestinal bleeding: flow-chart.

Conclusion

Out of four-year survey, pts with ongoing DOACs were less likely to have mGIH when compared to W.

Patients with W were more likely to receive reversal tratment; pts with DOACs were more likely to undergo admission. Short-term mortality of pts with W was higher than DOACs. Aggressive pharmacological approach should be driven by PTT, INR, ongoing warfarin, and older age.

Expected and actual adverse drug-drug interactions in elderly patients accessing the emergency department: data from the ANCESTRAL-ED study

OBJECTIVE

This study was aimed at evaluating the frequency and describing the adverse drug-drug interactions (DDIs) recorded among elderly patients accessing the emergency department (ED).

METHODS

Patients aged ≥65 years, accessing the ED of Pisa University Hospital (Italy) from 1 January 2015 to 31 December 2015 within the ANCESTRAL-ED program, were included in this study. 'Expected' DDIs were assessed using Thomson Micromedex®. Each ED admission (discharge diagnosis) consistent with the signs and symptoms of an expected DDI for each patient was classified as an 'actual' DDI.

RESULTS

Throughout the study period, 3473 patients (3812 ED admissions, 58% females, mean age: 80.3) were recorded. The total number of expected DDIs was 12,578 (67 contraindicated; 3334 major; 8878 moderate; 299 minor) detected in 2147 (62%) patients. Overall 464 expected DDIs were found to be consistent with the ED admission in 194 patients (representing 9% of patients with expected DDIs).

CONCLUSIONS

More than one half of elderly patients admitted to ED presented at least one expected DDI at the time of ED presentation. However, 9% of the expected DDIs were identified as actual DDIs, based on the consistency of the expected event with the ED discharge diagnosis.

Anti-Mullerian hormone (AMH) and ovarian function in young breast cancer (BC) women receiving adjuvant chemoterapy (CT)

e11544

Background: Fertility loss is a main side effect of adjuvant CT in young women with BC. AMH was evaluated as a potential marker of residual ovarian function after CT. Method: AMH (ng/mL), FSH (mIU/mL), E2 (pg/mL) and menstrual activity were evaluated before CT and every 3 months after CT in pre-menopausal BC patients ( pts ) enrolled in a phase III study evaluating the role of triptorelin in the prevention of CT-induced early menopause. Means were compared with Student t test for paired data, anova or ancova. The effect of age, CT regimen, FSH and AMH on time to menstrual resumption was investigated by means of the Cox's proportional hazards model. Results: Among 26 evaluable pts at baseline, mean age was 39 years (range 27-45). Baseline mean values were: FSH 5.67 (SD 4.88), E2 151.81 (SD 134.9), AMH 2.67 (SD 1.85). Levels of AMH were significantly lower (1.26) in old pts ( ≥ 41 yrs) as compared to younger ones (2.97 and 3.63 in 25–36 yrs and 37–40 yrs old women, respectively) (p=0.018). After CT, mean value of AMH significantly decreased from 2.04 ( SD 1.44 ) to 0.59 ( SD 0.59 ) (p=0.0003 ); FSH value increased, from of 8.64 (SD 12.99) to 23.13 (SD 25.80) (p=0.017) and E2 values decreased from 159.71 (SD 147.03) to 73.29 (SD 129.53) (p=0.02). The mean decrease of AMH levels was not affected by the type of CT regimens: -1.50, -1.52 and -1.33 after FEC ⋄ Paclitaxel, FEC ⋄ Taxotere and FEC/CMF, respectively (p=0.97). Among 10 pts with both early (0–5 months) and delayed (6–11 months) post-CT evaluations, no change in AMH values was observed with longer follow up: mean values were 1.49, 0.35 and 0.36, at baseline, after 0–5 months and after 6–11 months, respectively. Menstrual activity resumption occurred in 48% of patients. At multivariate analysis factors significantly associated with the lower probability of menstrual activity resumption after CT were: old age (p=0.05) and chemotherapy with FEC ⋄ docetaxel ( p=0.05 ). In this preliminary analysis baseline and after CT values of AMH were not significantly associated with menstrual resumption. Conclusions: Adjuvant CT significantly affects the levels of AMH in young women with BC. Further studies are needed to assess the role of AMH as a surrogate of ovarian toxicity induced by CT.

No significant financial relationships to disclose.

Chest pain unit management of patients at low and not low-risk for coronary artery disease in the emergency department. A 5-year experience in the Florence area

In this study, we screened a total of 6723 consecutive patients with chest pain and ECG non-diagnostic for acute myocardial infarction (AMI) on presentation to the emergency department (ED). The aim of the study was to avoid missed AMI, improve safe early discharge and reduce inappropriate coronary care unit (CCU) admission. Chest pain patients were triaged using a clinical chest pain score and managed in a chest pain unit (CPU). Patients with a low clinical chest pain score were considered at very 'low-risk' for cardiovascular events and discharged from the ED; patients with a high chest pain score were submitted to CPU management. Observation and titration of serum markers of myocardial injury were obtained up to 6 hours. Rest or stress myocardial scintigraphy (SPECT) was performed in patients > 40 years or with > or = 2 major coronary risk factors. Exercise Tolerance Test (ETT) or Stress-Echocardiogram (stress-Echo) were performed in younger patients or with < 2 coronary risk factor, or unable to exercise, respectively We discharged directly from the ED the majority of patients (4454; 66%): in this group there was only a 0.2% final diagnosis of coronary artery disease (CAD) at follow-up. The remaining 34% of patients, with non-diagnostic or normal ECG, were managed in the CPU. In this group, 1487 patients (representing 22% of the overall study group) were found positive for CAD, two-thirds because of delayed ECG or serum markers of myocardial injury, and one-third by Echo, SPECT or ETT. In conclusion, CPU based management allowed 22% early detection of myocardial ischaemia and 78% early discharge from the ED avoiding inappropriate CCU admission and optimizing the use of urgent angiography.

[Subarachnoid hemorrhage and the heart]

Electrocardiographic abnormalities had been reported, in patients with subarachnoid hemorrhage, with variable percentage from 2% to 91%, according to several studies. The most common changes are T wave inversion, ST segment elevation or depression, QT prolongation, U waves, atrial flutter and fibrillation, ventricular fibrillation, supraventricular tachycardia, premature atrial and ventricular contractions. These findings occur within the first forty-eight hours after the onset of the symptoms; they usually are benign and transient. In a small percentage of cases generally in severe ESA, the ECG changes are associated with ventricular asynergy, coronary vasospasm or subendocardic necrosis. The arrhythmias could be produced either by autonomic discharges to the heart, during increased sympathetic activity due to ESA, or by a damage of cerebral areas with arrhythmogenic capacity. The importance of ECG abnormalities towards mortality and morbidity in patients with ESA has not yet been cleared; however, a careful monitoring is recommended to prevent severe cardiac complications and to obtain an indirect, further evaluation of the neurologic pathology.

[Carcinogens in the urban environment of Italian cities: benzene and benzo(a)pyrenes]

In Italian urban areas air pollution from benzene and benzo(a)pyrene-B(a)P--is mostly caused by traffic. The concentration limits in the atmosphere fixed by Italian legislation up to December 31, 1998 expressed as annual means are 15 micrograms/m3 and 2.5 ng/m3 for benzene and B(a)P respectively and, starting from January 1, 1999, 10 micrograms/m3 and 1 ng/m3. In the city of Florence the concentrations detected and expressed as annual means of benzene and B(a)P in an area with heavy traffic (32.1 micrograms/m3 and 3.5 ng/m3), in a densely populated area (9.2 micrograms/m3 and 1.86 ng/m3), and in a city park (6.0 micrograms/m3 and 0.25 ng/m3), suggest a marked progressive reduction in the atmospheric levels of these chemicals with the distance from the main roads. The environmental data obtained from densely populated areas of a number of Italian cities (Firenze, Milano, Roma, Bologna, Bolzano, Pavia, Modena), the only ones that allow evaluation of the health risk, show benzene concentrations ranging from 6.0 to 11.3 micrograms/m3 and B(a)P levels, measured in heavy traffic areas, from 1.0 to 3.5 ng/m3 respectively (annual mean in 1996). The data obtained in the city of Florence show that the population is exposed weekly to average concentrations of 14.3 micrograms/m3 for benzene and 2.0 ng/m3 for B(a)P. These results suggest that, regarding benzene and B(a)P pollution, the situation in Florence is far from being critical but not such as to ensure that long-term exposure is without adverse effects.

[Validity of the V/Q index in the monitoring of critical patients]

The Authors have controlled the validity of VQI to quantify pulmonary shunt (Qs/Qt). The survey involved (group A) patients who had undergone major surgery and (group B) patients hospitalized in ICU for cardiorespiratory failure. Four subgroups were identified in both the groups according to different values of SaO2. A good correlation, already described by Räsänen, was comproved in the groups and subgroups. However a progressive reduction of the coefficient of correlation from the lower to the higher values of SaO2 was noted. Finally the differences observed between group A and group B, are supposed to be dependent on a greater variability of haemoglobin, in the surgical group, in relation to the time of evaluation.

Pulsed Doppler verification of atrial contribution to ventricular filling in sequential pacing

We have used pulsed Doppler to ascertain effective atrial contribution to ventricular filling in sequential pacemaker rhythm. The technique is particularly valuable when electrocardiographic evidence of atrial capture is uncertain.

Congenital absence of pain

A 16-year-old boy had congenital absence of pain sensitivity and no impairment of other sensory modalities. Routine electrophysiologic investigation showed no abnormalities. The threshold and latency of electrically elicited corneal reflex and cortical potentials evoked by tooth pulp stimulation were normal, but suprathreshold electric stimulation of corneal mucosa and dental pulp, as well as electric stimulation of dorsal roots, did not elicit pain. The total CSF opioid activity was raised. However, naloxone hydrochloride administration failed to reverse the analgesia. The axon reflex to intradermal injection of histamine dihydrochloride was absent. Cutaneous nerve branches showed unspecific changes affecting part of unmyelinated axons. most of the unmyelinated as well as the myelinated axons were normal. We consider the case an example of congenital indifference to pain.

Cardiac rhythmicity of skin sympathetic activity recorded from peripheral nerves in man

In previous microelectrode recordings of sympathetic impulse activity in human peripheral nerves a marked cardiac rhythmicity has been found in the spontaneous firing of vasoconstrictor neurones supplying the vascular bed of skeletal muscles. Evidence has been presented that this rhythmicity depends on a potent baroreflex control of these neurones which are significantly involved in blood pressure regulation. In contrast, no cardiac rhythmicity has previously been seen in the spontaneous firing of sympathetic fibres supplying vessels and sweat glands in the human skin. The present study shows that when strong sudomotor activity is induced in skin nerves by a rise in ambient temperature, the sudomotor impulses tend to occur in volleys time-locked to the cardiac cycle. A similar cardiac rhythmicity is not exhibited by the skin vasoconstrictor fibres which can be activated by lowering of the ambient temperature. Induced falls in blood pressure do not produce any baroreflex modulations of the sudomotor outflow, suggesting that the cardiac rhythmicity of the sudomotor impulses is mot dependent on the action of this reflex.

Acute experimental dental pain: a technique for evaluating pain modulating procedures

A simple method for bipolar electrical stimulation of the tooth pulp for evaluating pain modulating procedures is described. Stimulation selectivity has been studied by means of cortical evoked potentials before and after gum anaesthesia. Results obtained by constant current and constant voltage stimulation have been compared. Constant voltage stimulation has proved to be more stable in time. This technique is able to differentiate the analgesic effect of a single dose of i.v. lysine acetylsalicylate from saline. Threshold sensation was judged as painful by about half of the subjects.

Thermoregulatory and rhythm-generating mechanisms governing the sudomotor and vasoconstrictor outflow in human cutaneous nerves

1. Recordings of multiunit sympathetic activity were made from human nerve fascicles supplying hairy and glabrous skin of the extremities in healthy subjects exposed to different ambient temperatures. Sudomotor and vasomotor events accompanying the neural activity were monitored by simultaneous recordings of electrodermal and pulse plethysmographic events (Pleth) in the neural innervation zones. 2. By exposing the subject to warm (43 degrees C) or cold (15 degrees C) environments, it was possible to obtain a selective activation of either the sudomotor or the vasoconstrictor neural system, respectively, with suppression of spontaneous activity in the other system. 3. Bursts of both vasoconstrictor and sudomotor nerve activity were found to occur at certain preferred intervals which were integer multiples of a period of about 0 . 6 sec (100 cycles/min). With high sudomotor or vasoconstrictor tone the 100 cycles/min rhythm was prominent but with decreasing tone slower subharmonic rhythms prevailed. Respiratory rhythms were also discerned as well as slower rhythms attributable to oscillatory tendencies in thermoregulatory servos. 4. Vasoconstrictor bursts had longer mean duration than sudomotor bursts, a finding attributed to a slower conduction velocity of vasoconstrictor as compared to sudomotor impulses. 5. With increasing incidence of bursts transient electrodermal or plethysmographic responses following individual bursts merged, and thus the fast neural rhythms were not discernible in either the electrodermal or Pleth traces. Given increments in firing rate of nerves produced less additional vasoconstriction at high than at low firing rates. The rhythm generating mechanisms may help to restrict rates of individual fibres to the low range which provides high gain in the neuroeffector transfer functions.

Regional similarities and differences in thermoregulatory vaso- and sudomotor tone

1. Skin nerve sympathetic activity was recorded simultaneously from the following pairs of nerves: left and right median, median and peroneal, left and right peroneal, posterior cutaneous antebrachial and superficial radial, posterior cutaneous antebrachial and median. The recordings were performed on healthy subjects exposed to different ambient temperatures. Electrodermal responses and pulse plethysmograms were recorded from the neural innervation zones. 2. Vasoconstriction impulse bursts recorded simultaneously from the median and peroneal nerves during exposure to a cold environment showed a striking similarity with respect to the timing and strength of individual bursts. A similar strong correlation was observed also among sudomotor bursts recorded simultaneously from the posterior cutaneous antebrachial and superficial radial nerve during exposure to a warm environment. 3. On some occasions, such as during exposure to a moderately warm environment or emotional stress, a temporal correlation was also observed between vasoconstrictor bursts recorded from the median and sudomotor bursts recorded simultaneously from the posterior cutaneous antebrachial nerve. 4. The double nerve recordings provided evidence that in the distal glabrous skin areas reflex thermoregulatory functions are mainly executed via vasoconstrictor fibres whereas sudomotor fibres are brought into action only at relatively high temperature. On the contrary, in the hairy skin on the dorsal side of forearm and hand reflex thermoregulation is to a large extent executed via sudomotor fibres.

Corneal reflex elicited by electrical stimulation of the human cornea

The corneal reflex can be elicited in humans by electrical stimulation of the cornea. This method is harmless and allows precise quantification of the reflex response. In 18 patients with trigeminal lesions, the reflex was abolished or significantly altered on the diseased side in all cases. Measurement of the threshold is the most significant characteristic.

[Monocular ocular bobbing]

The ocular bobbing phenomenon consists of involuntary, abrupt, usually conjugate, brisk downward eye movements followed by a slow return to midposition; it is most often observed in cases of coma due to pontine vascular lesions. In the patient reported here, with a coma after basilar thrombosis, the movement was initially conjugate and subsequently limited to one eye, as described by SUSAC and coworkers under the heading "monocular bobbing" in 1970. The movement was increased in amplitude and frequency by labirintine caloric stimulation as well as by non specific manoeuvres like neck skin pinching and visual stimulation. Post-mortem examination showed a large ischaemic infarction of the pons, of the middle cerebellar peduncles and of the white matter of one cerebellar hemisphere.

[Congenital analgesia]

The case of a 12 years old boy with a congenital anaesthesia covering all cutaneous and visceral districts is reported. There were no other neurological abnormalities apart a light mental retardation and loss of axon reflex after intradermal injection of hystamine. Notwithstanding this last finding a diagnosis of congenital indifference to pain was made. The differential diagnosis between indifference and insensitivity to pain is discussed.

[Multielectronic computerized EMG: technical notes on the recording and parallel off-line elaboration]

A Multielectrodic EMG analysis program is developing. The purpose is to get as short as possible the main EMG parameters (amplitude, duration, frequency) of most motor units, and to reach an estimation of the anatomical extent of single units. According to the muscle extent a variable number of electrodes are inserted crosswise the fibers. EMG signals are simultaneously recorded on a multichannel AMPEX FR1300 and then off-line processed by a 21MX HP minicomputer connected with a 5Mbytes disc drive. Some technical problems had to be solved:channel amplification adjustment to avoid any difference among preamplifiers calibration and filtering, severe hum filtering of main power that is specially strong in nultielectrodic recording systems, the need of sampling at the same Nyquist time the signals of different channels. The computer is instructed to identify the "sinchronous" units i.e. the motor units recorded from more than one channel. These motor units are detected, counted and deleted from all the channels, except the one where they show the maximum amplitude. The percentage of these sinchronous units depends upon the interelectrodic distance and their anatomical area, thus it can support an evaluation of motor unit anatomical spread.

Selective Activation of peripheral nerve fibre groups of different diameter by triangular shaped stimulus pulses

1. The differential block of cutaneous nerve fibres has been achieved with a simple method of electrical stimulation, employing a single pair of active electrodes. 2. The method allows the selective activation of 95% of small myelinated (delta) axons, without activation of the larger (beta) ones; and activation of unmyelinated (C) fibres, without A fibre activation. Asynchronous firing of myelinated axons was absent in the majority of the experiments. 3. The method employs triangularly shaped electrical pulses, with a steep rise front and a slow exponential decay. The outward flow of current at the cathode fires conducted impulses in both larger and smaller axons, and the inward flow inactivates differentially the conduction in the smaller ones. 4. The differential effect of anodal currents rests upon the greater internal conductance and greater conduction velocity of larger fibres. 5. The method has the advantage over the conventional polarization block of simpler surgical preparation, longer nerve survival and minimal latency distortion. However, it cannot be applied in experiments requiring physiological stimulation of peripheral receptors.