The 5-HT(2) receptor activation enhances impulsive responding without increasing motor activity in rats

The effects of 5-HT(2) receptor ligands on the performance of rats were investigated using a 5-choice serial reaction time (5-CSRT) task. Systemic administration of DOI (0.03 to 0.3 mg/kg subcutaneously [SC]), a 5-HT(2) receptor agonist, did not impair choice accuracy of well-performing rats under either baseline conditions or more demanding conditions of the task, in which the stimulus duration or intensity were reduced or the intertrial interval (ITI) was decreased. DOI (0.1 mg/kg or 0.15 mg/kg) increased premature responding (the probability of intertrial interval hole pokes) in all testing conditions, except under conditions of a short ITI when the rats did not make any hole responses. Ketanserin (0.1 to 0.3 mg/kg SC), a 5-HT(2A) receptor antagonist, had no marked effect on performance. When combined with ketanserin (0.2 mg/kg SC), however, DOI (0.1 mg/kg) did not increase premature responding. The lowest doses of DOI (0.05 and 0.1 mg/kg) that increase premature responding had no effect on open-field performance. Further, the effects of systemically administered DOI were not reproduced by bilateral administration of DOI into the anterior cingulate cortex. These data indicate that excessive activation of 5-HT(2A/2C) receptors interferes with response control rather than visual attention. Furthermore, the DOI-induced enhancement of impulsive responses are not due to locomotor hyperactivity, and the anterior cingulate cortex is not the primary site of action for this enhancement of premature responding.     

TRH-induced blood flow and mean arterial pressure changes in the rabbit are not dependent on the anaesthetic used.

1. The effects of thyrotropin releasing hormone (TRH) on regional cerebral blood flow were studied in rabbits anaesthetized with pentobarbitone or ketamine. The blood flow was determined with the labelled microsphere method before and after the i.v. administration of either 50 micrograms kg-1 or 2 mg kg-1 TRH. 2. In order to measure the cerebral O2 consumption the arteriovenous difference in oxygen saturation in the brain (CAVOD) was measured before and after the administration of 2 mg kg-1 TRH. 3. In animals under pentobarbitone anaesthesia 50 micrograms kg-1 TRH elicited an increase in mean arterial blood pressure (MAP) of about 1 kPa and 2 mg kg-1 TRH elevated the MAP by about 2 kPa. With ketamine as the anaesthetic the corresponding values were 0.5 kPa and 7 kPa, respectively. TRH induced significant vasoconstriction in several peripheral tissues. 4. The total cerebral blood flow (CBFtot) increased from 54 +/- 4 to 78 +/- 5 g min-1 100 g-1 after the administration of 50 micrograms kg-1 TRH in pentobarbitone-anaesthetized animals. An even greater effect was elicited by 2 mg kg-1 TRH, from 48 +/- 6 to 113 +/- 19 g min-1 100 g-1. In ketamine-anaesthetized rabbits, 50 micrograms kg-1 TRH tended to enhance the CBFtot and 2 mg kg-1 increased it from 71 +/- 6 to 141 +/- 19 g min-1 100 g-1. 5. In animals anaesthetized with pentobarbitone, the CAVOD decreased from 47.3 +/- 1.7% to 35.1 +/- 2.2% at 3 min after TRH delivery, and then gradually increased to the control level.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mucoid presentation of acute enterocolitis in children: a hospital-based case-control study

A hospital-based case-control study was carried out to clarify the characteristics of mucoid presentation of acute enterocolitis in children. One hundred sixty-eight cases of acute mucoid enterocolitis (study population) were compared with 200 cases of watery diarrhoea and 118 cases of blood dysentery (control groups) on the basis of clinical characteristics and findings on stool examination. Study and control groups were comparable with respect to age, body weight and nutritional status. There was no significant difference in clinical characteristics (duration of diarrhoea, stool frequency, presence of vomiting, fever and dehydration) between patients suffering from mucoid enterocolitis and blood dysentery. However, watery diarrhoea patients had significantly high frequencies of vomiting (p = 0.00001) and dehydration (p     

The relationship between moisture or mould observations in houses and the state of health of their occupants.

This work was conducted in order to study how the health of adults is affected by the presence of moisture or mould in the home. A random sample of 310 houses in Finland was studied during the years 1993-1994. The houses were investigated for visual signs of moisture by a surveyor, and observations of mould were reported by the occupants. A moisture problem was observed in 52% and a mould problem in 27% of the houses. Health data was collected by means of a postal questionnaire from 699 adults. Exposure to moisture was significantly associated with sinusitis, acute bronchitis, nocturnal cough, nocturnal dyspnoea and sore throat, and the exposed inhabitants had significantly more episodes of common cold and tonsillitis. Exposure to mould was significantly associated with common cold, cough without phlegm, nocturnal cough, sore throat, rhinitis, fatigue and difficulties in concentration. Building-related moisture or mould increased the risk of upper and lower respiratory infections and symptoms as well as of nonrespiratory symptoms.     

Prevention of zoonotic animal diseases: a step towards co-operation among Nordic authorities?

Aim  

With globalisation, the spreading and consequences of serious animal diseases will become an increasingly realistic threat, also to Nordic countries, their food animals and consumers. It has already been suggested that it might be useful to establish an army to manage all co-operations among countries, for instance, for medical co-operation needs. In light of this, it might also be important to guarantee the security of animal products and to fight together against animal diseases, some of which are potentially dangerous for human beings. The aim of this study was to investigate how the laws concerning animal diseases construct the reality of co-operation among authorities in different Nordic countries.     

Comparison of the effect of gluconate, lactose, and xylitol on bone recalcification in calcium-deficient rats

The therapeutic value of three calcium absorption promoting carbohydrates, lactose, gluconate and xylitol, in bone calcification was evaluated in 7-week-old male rats which were fed on a semisynthetic Ca-deficient diet for 3 weeks. Lactose + CaCO₃, xylitol + CaCO₃, Ca-gluconate, or CaCO₃ alone were administered to the Ca-deficient rats for 2 weeks; the carbohydrate and Ca contents of the diets were 5% and 0.5%, respectively. The Ca-deficient rats showed a decrease in serum total Ca and ionized Ca²⁺ and in tibial Ca, Mg, P and density, with a concomitant increase in bone hydroxyproline concentration. Bone and serum tartrateresistant acid phosphatase activities were increased 2-fold and the serum 1,25(OH)₂D₃ level 5-fold. Smaller increases were found in serum calcitonin, PTH, alkaline phosphatase and osteocalcin levels. These changes (except calcitonin) were reversed by the administration of Ca and the carbohydrates. It was observed that all three agents improved the recalcification of bones compared with the effect of CaCO₃ alone. The effect of lactose and xylitol was superior to that of gluconate. These results suggest advantages in the use of xylitol in Ca-supplements.     

Effect of lateral release on patellar motion in chondromalacia: An MRI study of 11 knees

Preoperatively and postoperatively, patellar motion in 11 knees with chondromalacia was analyzed by MRI at 0°, 10°, 20°, and 30° of knee flexion. The preoperative patellar position clearly deviated from normal at 0°-10° of knee flexion. The lateral release operation corrected this deviation.     

Amniotic fluid retinol concentrations in late pregnancy

The concentrations of retinol (vitamin A) were measured in 36 samples of human amniotic fluid obtained near term. Mothers with normal pregnancy had higher amniotic fluid retinol levels than patients with diabetes or toxemia. The results indicate that some maternal complications during pregnancy affect the transport of retinol into amniotic fluid, possibly due to reductions in the uteroplacental blood flow.     

Amniotic fluid 25-hydroxyvitamin D concentrations in normal and complicated pregnancy

The concentration of 25-hydroxyvitamin D (25(OH)D) was measured in 85 samples of amniotic fluid (AF) obtained near term from mothers with normal pregnancy, diabetes, pre-eclampsia or intrahepatic cholestasis of pregnancy. Significantly lower AF 25(OH)D levels were found in diabetic mothers than in the three other groups. Our results suggest that the vitamin D status of the fetoplacental unit may be somewhat impaired in diabetic pregnancy.