A 512-channels, whole array readout, CMOS implantable probe for acute recordings from the brain.

The integration of implantable CMOS neural probes with thousands of simultaneously recording microelectrodes is a promising approach for neuroscience and might allow to literally image electrophysiological neuronal activity in multiple brain circuits as we have previously shown in vitro. Here, we present a complete system based on a fully multiplexed CMOS neural probe that was designed for in-vivo acute recordings with a scalable circuit architecture. In particular, a first prototype of a single-shaft probe with 512 electrodes was realized in a standard CMOS 0.18µm technology and post-processed to structure the shaft with a wedge-like geometry of 30µm in thickness at the tip and 80µm at the base. The design of the system and of the probe as well as the post-processing techniques are discussed. Finally, preliminary results on electrical, mechanical and implantation tests are presented to demonstrate the feasibility of our approach.

Peripheral neural activity recording and stimulation system.

This paper presents a portable, embedded, microcontroller-based system for bidirectional communication (recording and stimulation) between an electrode, implanted in the peripheral nervous system, and a host computer. The device is able to record and digitize spontaneous and/or evoked neural activities and store them in data files on a PC. In addition, the system has the capability of providing electrical stimulation of peripheral nerves, injecting biphasic current pulses with programmable duration, intensity, and frequency. The recording system provides a highly selective band-pass filter from 800 Hz to 3 kHz, with a gain of 56 dB. The amplification range can be further extended to 96 dB with a variable gain amplifier. The proposed acquisition/stimulation circuitry has been successfully tested through in vivo measurements, implanting a tf-LIFE electrode in the sciatic nerve of a rat. Once implanted, the device showed an input referred noise of 0.83 µVrms, was capable of recording signals below 10 µ V, and generated muscle responses to injected stimuli. The results demonstrate the capability of processing and transmitting neural signals with very low distortion and with a power consumption lower than 1 W. A graphic, user-friendly interface has been developed to facilitate the configuration of the entire system, providing the possibility to activate stimulation and monitor recordings in real time.

A multi-channel low-power system-on-chip for single-unit recording and narrowband wireless transmission of neural signal.

This paper reports a multi-channel neural recording system-on-chip (SoC) with digital data compression and wireless telemetry. The circuit consists of a 16 amplifiers, an analog time division multiplexer, an 8-bit SAR AD converter, a digital signal processor (DSP) and a wireless narrowband 400-MHz binary FSK transmitter. Even though only 16 amplifiers are present in our current die version, the whole system is designed to work with 64 channels demonstrating the feasibility of a digital processing and narrowband wireless transmission of 64 neural recording channels. A digital data compression, based on the detection of action potentials and storage of correspondent waveforms, allows the use of a 1.25-Mbit/s binary FSK wireless transmission. This moderate bit-rate and a low frequency deviation, Manchester-coded modulation are crucial for exploiting a narrowband wireless link and an efficient embeddable antenna. The chip is realized in a 0.35- εm CMOS process with a power consumption of 105 εW per channel (269 εW per channel with an extended transmission range of 4 m) and an area of 3.1 × 2.7 mm(2). The transmitted signal is captured by a digital TV tuner and demodulated by a wideband phase-locked loop (PLL), and then sent to a PC via an FPGA module. The system has been tested for electrical specifications and its functionality verified in in-vivo neural recording experiments.

[The activity of local health units in agriculture: promotion, prevention, control]. / Attività di promozione, prevenzione e controllo delle ASL/AUSL in ambito agricolo.

Agriculture shows an high proportion of injuries, mostly by machineries and instruments, and the highest proportion between fatal and total injuries. The Conference of Regions has adopted the National Agriculture and Forestry Prevention Plan, in application of the "Pact for health and safety in workplaces". The plan gives priority to actions improving the safety of agricultural machines, specially if more frequently involved in serious and fatal injuries. Goal is to achieve an homogenous intervention standard all over in the country, composed by a mix of information, support and control, addressed to farms and agricultural machines traders. Public prevention organizations of Local Health Units moreover will record homogenously the happen modality of fatal and serious accidents, will collaborate in joining prevention objectives with Rural Develop Plans and in drawing up good practices. At another level in some regions have been developed prevention activities for other risk factors: definition of exposition profiles of pesticides, development of professionally exposed workers formation, control of buildings and cattle breeding, medical and epidemiological periodic survey of employees.

[Role of a surveillance system developed by the Viareggio Local Health Unit in injury prevention]. / Ruolo di un osservatorio infortuni per l'azione di prevenzione del servizio di Prevenzione, Igiene e Sicurezza nei Luoghi di Lavoro (PISLL).

BACKGROUND: Statistics on occupational injuries published by INVAIL (National Insurance Institute for Occupational Accidents and Diseases) are not useful to plan appropriate preventive actions in local manufacturing sectors. METHODS: The injury surveillance system, developed by Viareggio Local Health Unit, collects data on all occupational injuries that occurred in the Versilia area, by enterprise, worksite and manufacturing sector. Enterprises operating in particular sectors (e.g. shipyards, construction) are classified differently than in the national injury surveillance system. After trend analysis and interpretation of injury data, the main results are available both in electronic and paper format. RESULTS AND CONCLUSIONS: Surveillance data are used by the Local Health Unit to promote and formulate specific preventive actions, such as: research and development of safer tools, promotion and control of safer use of specific tools, promotion and enforcement of good practices, control programmes in high risk manufacturing sectors and jobs.

Cytogenetic monitoring of a group of Italian floriculturists: no evidence of DNA damage related to pesticide exposure.

The induction of sister chromatid exchanges (SCE), structural chromosome aberrations (CA) or micronuclei (MN) was investigated in peripheral lymphocytes of a group of Italian floriculturists exposed to a mixture of pesticides. No statistically significant difference in the frequencies of cytogenetic damage was detected between exposed and control subjects. Assessment of the effect of confounding factors indicated that smoking affected both SCE and CA frequencies. Multiple regression analysis showed that in heavy smokers (> or = 20 cigarettes/day), SCE and CA levels increased significantly by 17% and 54%, respectively, as compared to non-smokers.

Cytogenetic biomonitoring of styrene-exposed plastic boat builders.

Earlier studies have produced evidence for an association between work-related styrene exposure and cytogenetic damage, while more recent studies have failed to show such an association. In the present study, chromosome aberrations (CA) and sister chromatid exchanges (SCE) were measured in peripheral blood lymphocytes of 46 male workers employed in a fiber-reinforced plastic boat building factory and exposed to styrene. Two groups of 23 workers each, characterized by different exposure levels (ranges: 2-120 mg/m3 and 86-1389 mg/m3 ambient air) were studied, fifty-one controls matched by sex, age and smoking habits were included. Randomized blood samples were analyzed for cytogenetic damage separately in two laboratories. Interlaboratory differences in the scoring of CA and SCE were noted. However, increases of the considered cytogenetic endpoints in exposed vs control groups were consistently observed in both laboratories. Multivariate statistical analysis of pooled data revealed increases of CA ranging between 19% (RR = 1.19; 95% C.I., 0.80-1.78; chromatid-type aberrations, low exposure group) and 144% (RR = 2.44; 95% C.I., 1.26-4.70; chromosome-type aberrations, high exposure group). Parallel excess of SCE in styrene exposed workers was also observed, although at a lesser extent (RR = 1.22; 95% C.I., 1.05-1.43, low exposure group; RR = 1.26; 95% C.I., 1.07-1.47, high exposure group). These findings suggest the presence of a causal association between occupational exposure to styrene and cytogenetic damage in the plastic boat building factory that was the object of the study.

Nitrate and nitrite exposure in Italian populations with different gastric cancer rates.

Exposure to nitrate and nitrite from dietary sources was estimated by questionnaire and measurement of salivary levels of the ions in residents of four regions of Italy with longstanding, contrasting, gastric cancer mortality rates. Whether using salivary levels or dietary questionnaire estimations no association was found between nitrate and nitrite exposure and gastric cancer mortality rates. For salivary nitrate and nitrite, the intra-provincial variation was greater than any inter-province difference. However, for dietary nitrate and nitrite intakes, there were significant differences between the regional groups (but not related to gastric cancer risk). Despite the limitations of the methods used, there was a weak positive association between salivary concentrations of nitrate and questionnaire assessment. Dietary factors are likely to play key roles at different stages of the gastric carcinogenic process. Nitrate may play a part but is unlikely to be a rate-limiting factor in all individuals or populations.

[Extraction of di-2-ethylhexylphthalate from PVC used in synthetic leather]. / Studio della cessione del di (2-etilesil) ftalato da finte pelli in PVC.

The extraction of the plasticizer di (2-ethylhexyl) phthalate (DOP) from PVC plastics was evaluated with a solvent mixture similar to that found in shoemaker's glues, sunflower oil, and in an aqueous emulsion resembling crude human sweat as far as the solubility of many organic compounds, including plasticizers is concerned. The aim was to evaluated the availability of plasticizers to be absorbed at skin level in PVC plastics, used as synthetic leather. The results indicated that the extraction of DOP is of practical importance only in the presence of a solvent mixture. Therefore the direct skin contact with PCV plastics containing DOP is much less significant as regards plasticizer absorption.

Impairment of nervous system in workers exposed to inorganic mercury.

Impairment of nervous functions has been investigated by clinical and neurophysiological methods in 55 workers exposed to inorganic mercury intoxication and 27 controls living in the same area. A polyneuropathy, mainly of sensory type, has been found in 6 exposed workers (10,9%) and 2 control (7,4%); a mono or multineuropathy of sensory or motor type was present in 15 exposed (27%) and 10 control (29,6%) subjects. Central N.S. involvement has been found in 7 out of 12 exposed workers examined and in 1 out of 7 controls by electronystagmography. Neurological examination demonstrated minor signs of cerebellar type in 3 instances.

Behavior of some psychological parameters in a population of a Hg extraction plant.

52 workers of a plant transforming Hg mineral were subjected to psychological investigation in order to detect behavioral alterations which might be related to Hg exposure. A group of 29 subjects living in the same area was used as the control. The test battery included reaction times, mental efficiency measures, and personality indexes for a total of 33 variables. Results were analyzed through statistical elaboration using parametric tests. Efficiency and memory measures could discriminate exposed individuals from controls; for the personality profiles, an interpretation explaining the differences observed is proposed in terms of a dynamic profile having different characteristics in the different groups studied. Reference to existing literature is made to verify any possible correlation with other authors' findings.

Effects of a xanthine derivative (BL 191) on insulin secretion in normal man.

A xanthine derivative, named BL-191, was administered iv in 8 healthy volunteers alone and in association with glucose (0.33 g/kg body weight iv) or glybenclamide (1 mg iv). BL-191 was infused iv at a constant rate in a dose of 200 mg during 45 minutes. Blood glucose, free fatty acids and immunoreactive insulin were measured during one hour. It was impossible to demonstrate neither a direct effect nor an enhancement of insulin secretion during drug administration; in another experiment (treatment F) a higher dosage of BL-191 (100 mg as a priming dose + 200 mg as infusion dose) was likely ineffective. It appears that some difference in insulin response may be present in the single subject (not evident in the mean), indicating a difference in the beta-cell cAMP-system sensitivity in individuals. These negative results allow some considerations on the importance of the beta-cell cAMP-system in healthy human beings.