A characterization of approach and avoidance learning in alcohol-preferring and alcohol-nonpreferring rats

Although numerous biochemical and physiological differences have been shown to be correlated with alcohol preference, less is known about behavioral factors that may correlate with alcohol preference. Using a signaled barpressing task, alcohol-preferring (P; n = 18) and alcohol-nonpreferring (NP; n = 19) rats were compared for their ability to learn an appetitive and an aversive task. Results showed that P rats had difficulty learning the tasks in comparison with NP and nonselected, control rats when appetitive training was given first. However, if aversive training came first, the NP rats performed poorly in comparison with the P and nonselected rats. These results suggest that these lines of rats may differ in behavioral inhibition and sensitivity to conditioned fear. Furthermore, these behavioral differences may offer a richer analysis of the traits that were co-selected with the alcohol-seeking and alcohol-avoiding phenotypes.     

Otogenic brain abscess

BACKGROUND: Otogenic complications are rare but typical following acute or chronic ear infections like mastoiditis and cholesteatoma. A life-threatening sequela is the otogenic brain abscess located in the temporal lobe or cerebellum. PATIENTS: At the ENT Department of the Medical University of Hannover/Germany we treated 8 patients suffering from otogenic brain abscesses in the temporal lobe during the last three years. The average age of the 6 male and 2 female patients was 48 years. In 5 patients the abscess developed due to a cholesteatoma with superinfection. Three cases showed acute mastoiditis. All patients were operated using an otosurgical retroauricular approach, in five cases a classical radical mastoidectomy was performed. In two cases the abscess was reached via mastoidal approach and was subsequently drained. In two other cases the abscess was drained some days later by neurosurgical approach due to increased neurological symptoms. The other patients were treated with high-dosed antibiotics under regular clinical and radiological control. RESULTS: In 7 cases complete regression of the abscess was achieved. Five patients were discharged without further otological or central-nervous problems. One female patient developed severe meningitis with generalized thrombosis of the central blood sinus system and died in central circulatory failure. Two other patients developed a moderate psychopathologic syndrome and were admitted to rehabilitation institutions. CONCLUSIONS: The analysis of our patients shows that otogenic brain abscesses should be regarded especially as a severe complication of the untreated cholesteatoma. It is important to use modern imaging modalities like computer tomography or MRI for early detection of the intracerebral lesion and to perform an early otosurgical intervention. Under antibiotics and CT control, healing of this severe complication can be achieved in most cases. However, the danger of acute and chronic ear diseases has to be kept in mind in all medical disciplines.     

Neurofilament protein is differentially distributed in subpopulations of corticocortical projection neurons in the macaque monkey visual pathways

Previous studies of the primate cerebral cortex have shown that neurofilament protein is present in pyramidal neuron subpopulations displaying specific regional and laminar distribution patterns. In order to characterize further the neurochemical phenotype of the neurons furnishing feedforward and feedback pathways in the visual cortex of the macaque monkey, we performed an analysis of the distribution of neurofilament protein in corticocortical projection neurons in areas V1, V2, V3, V3A, V4, and MT. Injections of the retrogradely transported dyes Fast Blue and Diamidino Yellow were placed within areas V4 and MT, or in areas V1 and V2, in 14 adult rhesus monkeys, and the brains of these animals were processed for immunohistochemistry with an antibody to nonphosphorylated epitopes of the medium and heavy molecular weight subunits of the neurofilament protein. Overall, there was a higher proportion of neurons projecting from areas V1, V2, V3, and V3A to area MT that were neurofilament protein-immunoreactive (57-100%), than to area V4 (25-36%). In contrast, feedback projections from areas MT, V4, and V3 exhibited a more consistent proportion of neurofilament protein-containing neurons (70-80%), regardless of their target areas (V1 or V2). In addition, the vast majority of feedback neurons projecting to areas V1 and V2 were located in layers V and VI in areas V4 and MT, while they were observed in both supragranular and infragranular layers in area V3. The laminar distribution of feedforward projecting neurons was heterogeneous. In area V1, Meynert and layer IVB cells were found to project to area MT, while neurons projecting to area V4 were particularly dense in layer III within the foveal representation. In area V2, almost all neurons projecting to areas MT or V4 were located in layer III, whereas they were found in both layers II-III and V-VI in areas V3 and V3A. These results suggest that neurofilament protein identifies particular subpopulations of corticocortically projecting neurons with distinct regional and laminar distribution in the monkey visual system. It is possible that the preferential distribution of neurofilament protein within feedforward connections to area MT and all feedback projections is related to other distinctive properties of these corticocortical projection neurons.     

Nucleation and growth kinetics of reaction-product formation for copper–titanium and silver–titanium alloys on alumina

A nucleation and growth mechanism is proposed for the formation of the reaction product at the interface between polycrystalline alumina and liquid-metal alloy drops containing titanium. The reaction product had been previously identified to be an oxide of titanium. The growth of reaction product islands was clearly observed at the alumina–metal interface using optical microscopy after dissolving the metal droplets with acid. The fractional coverage was quantified as a function of time and, by assuming Avrami-type reaction kinetics, surface reaction rate constants, k, were calculated for copper–titanium and silver–titanium alloys on alumina. Reaction rate constants between 1.4 × 10^-4 and 18 × 10^-4 s^-2 were obtained for copper–titanium alloys on alumina. The k values for silver–titanium alloys were found to be an order of magnitude lower (2.5 × 10^-6 and 7.2 × 10^-6 s^-2) then the k values obtained for copper–titanium alloys on alumina. This revised version was published online in November 2006 with corrections to the Cover Date.     

Effect of training on endoscopic intracorporeal knot tying

Training in endoscopic, intracorporeal knot tying, was evaluated in 29 obstetrics and gynaecology trainees who performed 100 consecutive intracorporeal, two turn, flat, square knots. An obvious learning curve was observed. With training the quality of the knots increased, whereas the mean duration to tie a knot decreased from 277 +/- 114 to 67 +/- 27 s for the first 10 and the last 10 knots respectively. The initial and final duration of knot tying were lower in more experienced trainees, as estimated by the year of training or the Royal College of Obstetrics and Gynaecology (RCOG) level of experience. More specifically, duration of knot tying was shorter when more diagnostic laparoscopies, laparoscopic sterilizations or adnexectomies had been performed. This effect of previous experience was however limited compared with the overall effect of training. Previous passive experience, however, as determined by the number of assisted or observed surgical interventions, did not affect the learning curves. Speed of knot tying was slightly higher in trainees who spent more of their leisure time performing handicrafts than in trainees who were more interested in reading, but although significant, these differences were only marginal. In conclusion, the data show an important effect of training on the speed and quality of intracorporeal knot tying and confirm that learning curves improve with previous training.     

Pathobiology of lipopolysaccharide

Lipopolysaccharide is a component of the gram-negative bacterial cell wall that is responsible for 25,000-50,000 deaths in the United States each year. The sequelae of gram-negative infection and septicemia leading to death include fever, hypotension with inadequate tissue perfusion, and disseminated intravascular coagulation. It is clear that different cell types respond differently to lipopolysaccharide. Furthermore, various autacoids and cytokines are released that can affect cellular function even in cell types that do not recognize lipopolysaccharide. Despite advances made in the etiology of septic shock and organ failure, therapy is still for the most part supportive and largely ineffective. The aim of this review is to summarize the current understanding of the role of lipopolysaccharide in the development of septicemia by examining signal transduction and therapeutic approaches.     

Risk factors for acute myocardial infarction in Indians: a case-control study

BACKGROUND: South Asians who have settled overseas and those in urban India have an increased risk of ischaemic heart disease (IHD). Reasons for this increased risk are unclear. Most studies have been based on migrants to western nations, so their findings may not apply to most south Asians, who live in their own countries. Therefore, we assessed the relative importance of risk factors for IHD among South Asians in Bangalore, India. METHODS: We conducted a prospective hospital-based case-control study of 200 Indian patients with a first acute myocardial infarction (AMI) and 200 age and sex matched controls. We recorded prevalence of the following risk factors for IHD: diet, smoking, alcohol use, socioeconomic status, waist to hip ratio (WHR), blood glucose, serum insulin, oral glucose tolerance test, and lipid profile. FINDINGS: The most important predictor of AMI was current smoking (odds ratio [OR] 3.6, p < 0.001) of cigarettes or beedis (a local form of tobacco), with individuals who currently smoked 10 or more per day having an OR of 6.7 (p < 0.001). History of hypertension and of overt diabetes mellitus were also independent risk factors (OR 2.69 [p = 0.001] and 2.64 [p = 0.004], respectively). Among all individuals, fasting blood glucose was a strong predictor of risk over the entire range, including at values usually regarded as normal (OR adjusted for smoking, hypertension, and WHR 1.62 for 1 SD increase, p < 0.001). Abdominal obesity (as measured by WHR) was also a strong independent predictor across the entire range of measures (OR adjusted for smoking, hypertension, and blood glucose 2.24 for 1 SD increase; p < 0.001). Compared with individuals with no risk factors, individuals with multiple risk factors had greatly increased risk of AMI (eg, OR of 10.6 for the group with smoking and elevated glucose). Lipid profile was not associated with AMI. In univariate analyses, higher socioeconomic (income) status (OR 0.32, p = 0.005 highest vs lowest; OR 0.75 middle vs lowest) and vegetarianism (OR = 0.55, p = 0.006), seemed to be protective. The impact of vegetarianism was closely correlated with blood glucose and WHR. INTERPRETATION: Smoking cessation, treatment of hypertension, and reduction in blood glucose and central obesity (perhaps through dietary modification) may be important in preventing IHD in Asian Indians.     

Changes in the cellular energy state affect the activity of the bacterial phosphotransferase system

Synthetic oligonucleotide primers based on cDNA sequence were used to amplify the region spanning intron 2 of the alpha-globin gene of the bivalve mollusc Anadara trapezia. Amplification of this region from individual clams showed highly polymorphic patterns. The sequence of this intron was found to include a number of mono- [d(T)n and d(C)n], di- [d(CA)n and d(CT)n] and tetranucleotide d(CTGT)n repeats which were found to be polymorphic with respect to the types and numbers of repeats present. Two separate repeat-containing polymorphic regions were located near each end of this intron. The repeat at the 3' end consisted of an unusual example of a d(T)n polymorphism at the position of the polypyrimidine tract usually involved in intron splicing. Thirteen individual cloned intron 2 sequences, derived by PCR amplification from pooled genomic DNA, were sequenced without finding two identical sequences. All of the sequenced clones contained microsatellite sequences.