Position sensitivity of human muscle spindles: single afferent and population representations

The representation of joint position at rest and during movement was investigated in 44 muscle spindle primary afferents originating from the extensor carpi radialis brevis (ECRb) and extensor digitorum (ED) of normal human subjects. Position sensitivity was estimated for each afferent, and 43 of 44 were position sensitive. In each trial, six sequential ramp-and-hold movements (2-6 degrees, 2 degrees/s, total 24 degrees) flexed the relaxed wrist, beginning from the angle at which the afferent was just recruited. Joint position was represented by three specific features of afferent firing patterns: the steady-state firing rate during the 4-s hold period between ramps, the initial burst at the beginning of each ramp, and the ramp increase in firing rate later in the movement. The position sensitivity of the initial burst (1.27 +/- 0.90 pps/degree, mean +/- SD) was several times higher than that of the hold period (0.40 +/- 0.30 pps/degree) and not different from that of the ramp increase in firing rate (1.36 +/- 0.68 pps/degree). The wrist position sensitivities of ECRb and ED afferents were equivalent, as were their recruitment angles and angular ranges of position sensitivity. Muscle spindle afferents, both individually and as a population, were shown to represent static joint position via the hold rate and the initial burst. Afferents were recruited over the entire 110 degree range of wrist positions investigated; however, the angular range over which each feature represented joint position was extremely limited (approximately 15 degrees). The population response, based on the summed activity of the 43 afferents, was monotonically related to joint position, and it was strongly influenced by the afferent recruitment pattern, but less so by the position sensitivities of the individual afferents.     

Multi-rooted mandibular premolars: report of case

Differential growth of the epithelial diaphragm is needed for the formation of multiple roots in the primary and permanent dentitions. In most instances, the mandibular premolars possess a single root. It is a very unusual event to find a case of bilateral multi-rooted first and second mandibular premolars. This paper presents such a case.     

Risk of increase in nosocomial infections incidence in a surgical clinic. A case-control study

The complex activities of epidemiological surveillance of nosocomial infections (NI) have, among the main objectives, the identification of the causes and the assessment of risk factors. In 2002, the Clinic Hospital of Pneumology Iasi had 220 beds and was divided into the following units: Pneumophtisiology Unit (PPU), Thoracic Surgery Unit (TSU) and Intensive Care Unit (ICU). The global incidence of NI was of 0.85%. The incidence of cases with NI in the TSU and ICU increased to 5.39% in the interval April-June 2002 so that urgent epidemiological measures were applied to limit the phenomenon. After that, a case-control study was proposed in order to identify and assess the risk levels. The retrospective study met the methodological conditions such as case definitions for NI and post-surgical NI, for extrinsic and intrinsic risk factors, the selection of cases according to inclusion and exclusion criteria, the formation of the representative sample. The study included 16 patients with pleural NI and 55 controls with the pleurotomy performed between April-June in the TCU, as a common feature. The factors that increased the probability of a post-surgical NI development were: the external pleural drainage maintained more than 30 days (OR = 185.5; p < 0.0001 for CI = 95%), tuberculosis as the most important associated disease among the patients' pathological history records (OR = 28.0; p < 0.0001; CI = 95%); the antibiotherapy with multiple associations (OR = 3.30; p < 0.04; CI = 95%). The conclusions underlined that the patients suffered from tuberculosis since the very admission, which need pleurotomy have an increased risk to develop a NI. This fact should require an appropriate epidemiological, clinical and microbiological surveillance and the empirical antibiotic strategy or that conducted by the antibiogram results has to be performed adequately, according to the operative recommendations.     

Acute viral encephalitis. Experience of the Iaşi Infectious Disease Clinic between January 2000 and March 2003

We analyzed the patients files suffered from acute viral encephalitis in 39 months period: January 2000-march 2003. According to our data there was a total of 33 patients; one of them died. The most involved patients were male and of the 8-14 year group of age; for the first three month in 2003 were admitted 11 patients. Coma and seizures were the most frequent clinical signs. LCR had the usual abnormalities for the above mentioned disease; the treatment was mainly performed with corticosteroids; 28 cases were admitted more than 8 days period. The evolution of the clinical status was satisfactory for all 32 patients.     

Epidemiologic and clinical aspects of acute hepatitis B in the past decade

To study the clinical and epidemiological aspects of acute B hepatitis during the last 11 years. We retrospectively studied 1712 patient files, admitted in the Department of Infectious Diseases Ia?i, with acute B hepatitis between 1992-2002. The majority of the patients (69%) had an urban origin. Teenagers and young adults were predominantly affected (59% had between 15 and 34 years). A point of entry of the pathogen was identified only in 20% of the patients. The mean incubation period was 4 month. 24% of the patients had a prolonged form of the disease (over 30 days of jaundice). A fulminant evolution was noted in 1.2% of cases. Extrahepatic involvement was described in 25% of the patients. The global mortality was 1.15%. The number of patients with acute B hepatitis decreased by half during the last 11 years.