The restorative effect of naps on perceptual deterioration

Human performance on visual texture discrimination tasks improves slowly (over days) in the absence of additional training. This 'slow learning' requires nocturnal sleep after training and is limited to the region of visual space in which training occurred. Here, we tested human subjects four times in one day and found that with repeated, within-day testing, perceptual thresholds actually increased progressively across the four test sessions. This performance deterioration was prevented either by shifting the target stimuli to an untrained region of visual space or by having the subjects take a mid-day nap between the second and third sessions.     

Superantigen-induced T cell responses in acute rheumatic fever and chronic rheumatic heart disease patients

CD4+ and CD8+ T cells from healthy donors, acute rheumatic fever (ARF) and chronic rheumatic heart disease (CRHD) patients responded variably to a superantigen from Streptococcus pyogenes--Streptococcal pyrogenic erythrogenic toxin A (SPE-A). In vitro culture of CD4+ T cells from ARF patients (CD4-ARF) with SPE-A exhibited a Th1 type of response as they produced high levels of IL-2, while CD4+ T cells from CRHD patients (CD4-RHD) secreted IL-4 and IL-10 in large amounts, i.e. Th2 type of cytokine profile. The skewing of human CD4+ T cells (in response to SPE-A stimulation) to Th1 or Th2 type reflects the role of the two subsets in a disorder with differing intensities at the two extremes of the spectrum. Moreover, the anergy induction experiments revealed that CD8-ARF and CD8-RHD undergo anergy (to different extents), whereas CD4+ T cells do not, in response to re-stimulation by SPE-A. These results initially demonstrate that both CD4+ and CD8+ T cells respond differentially to SPE-A, and hence it is an important observation with respect to the pathogenesis of ARF/CRHD. Anergy in CD8+ T cells in the presence of SPE-A in vitro goes a step further to show the clinical relevance of these cells and their possible role in suppression of the disease.     

Microsmatic primates: reconsidering how and when size matters

The terms "microsmatic" and "macrosmatic" refer to species with lesser or greater levels, respectively, of olfactory function. Historically, primates are considered microsmats (olfactory sense reduced) with a concomitant increased emphasis on vision. The olfactory bulbs (forebrain centers that receive peripheral olfactory input) are proportionately smaller in primates compared to most other mammals. Similarly, the regions of the nasal cavity that are covered with olfactory epithelium (containing receptor cells) have proportionately less surface area in primates than other mammals. Thus, the generalization that primates are microsmatic is most frequently stated in terms of the proportional rather than absolute size of olfactory structures. Yet the importance of scaling to body size is unclear in regard to the chemical senses such as the olfactory or vomeronasal systems-do chemosensory structures such as olfactory bulbs and olfactory epithelium exhibit the same neural relationship to body mass that is seen for neural tissues that supply innervation to musculature or the skin? Previous studies examining neuronal density, volume, and/or surface area of the olfactory epithelium illustrate that different conclusions may be supported based on the parameter used. Plots of olfactory bulb volume versus body mass that generated for large-scale taxonomic studies or growth studies benefit from body mass (or total brain volume) with a comparative perspective. However, our examination of proportional versus absolute measurements implies that in comparisons within taxa, body size adjustments needlessly distort the data. As a final consideration, another embryonic derivative of the nasal placode, the vomeronasal organ, may warrant consideration regarding a definition of microsomia versus macrosomia.     

p-Dimethoxy-substituted trans-octahydrobenzo[f]- and -[g]quinolines: synthesis and assessment of dopaminergic agonist effects

The N-n-propyl homologues of the title compounds were prepared for further assessment of the ability of the "p-dimethoxy" moiety to confer dopaminergic agonism upon a variety of ring systems. Both the angularly and the linearly annulated trans-benzoquinoline ring derivatives displayed prominent DA2 dopaminergic effects on the peripheral sympathetic nerve terminal and displayed postjunctional dopamine receptor agonist properties in the striatum. It is speculated that the angular octahydrobenzo[f]quinoline derivative (but not the linear octahydrobenzo[g]quinoline derivative) may owe its dopamine-like effects to metabolic activation phenomena. In contrast, the cis-fused isomer of the angularly annulated benzoquinoline was inactive, as was the simple benzene derivative N,N-di-n-propyl-beta-(2,6-dimethoxyphenyl)ethylamine.     

Use of ivabradine for treatment of junctional ectopic tachycardia in post congenital heart surgery

Cardiac surgeries especially involving crux of the heart as performed in tetralogy of Fallot (TOF) and pulmonary stenosis are mainly responsible for junctional ectopic tachycardia (JET). Diversified antiarrhythmic agents have been used in an impressive way to treat JET but showed suboptimal efficacy and varied associated adverse effects. But, ivabradine has proved as final crusader for its treatment. We report our initial experience of 4 cases in last 6 months with ivabradine in the management of postoperative JET. Encouraged by various reports and our increasing experience with ivabradine in heart failure population, we have moved to ivabradine as the first drug of choice for postoperative JET. Bradycardia was the only significant adverse effect in our series. The availability of atrial and ventricular pacing wires or at least transvenous temporary pacing should be ensured before starting ivabradine.     

Gastric polyposis caused by multiple carcinoids and early carcinoma.

A case of gastric polyposis caused by multiple carcinoids with concurrent gastric carcinoma is reported in a 70 year old woman with severe atrophic gastritis and intestinal metaplasia. On microscopic examination, the carcinoids and gastric carcinoma arose separately thus representing "double primaries". Long-standing hypergastrinaemia probably plays a causative role in the development of carcinoma and carcinoids. Carcinoid tumours, although of low malignant potential, may be important as indicators of other unrelated high risk malignancies. Patients with carcinoids should be followed closely, especially as the incidence of these tumours seems to be on the increase.     

Bile-duct diameter at the porta hepatis and liver biopsies in Indian children with biliary atresia

Fibrous remnants from the porta hepatis and wedge biopsies of the liver were studied in 60 patients with biliary atresia. The patients were divided into three groups on the basis of bile duct diameter — I: no ducts; II: <50 m; III: >50 m. The liver damage was classified into three grades on the basis of ductular and parenchymal histopathologic changes and extent of inflammatory pathology. There was no correlation between severity of hepatic damage and duct diameter, although the levels of serum bilirubin and alkaline phosphatase varied in direct proportion to the degree of hepatic damage. There was an inverse relationship between age and duct diameter, but neither correlated with bile flow at surgery or in the postoperative period. The data suggest that Indian children with biliary atresia follow a different clinical course compared to those from Japan and Western countries. Correspondence to: V. Bhatnagar     

Giant ameloblastoma of the upper jaw

Ameloblastoma is the most frequently seen epithelial Odontogenic tumour, relatively uncommon, comprising about 1% of tumours and cysts arising from the Jaws.     

The effects of neonatal handling on the development of the adrenocortical response to stress: implications for neuropathology and cognitive deficits in later life

Several years ago Levine, Denenberg, Weininger, Ader, and others described the effects of postnatal "handling" on the development of behavioral and endocrine responses to stress. The handling procedure usually involved removing rat pups from their cages, placing the animals together in small containers, and 15-20 min later, returning the animals to their cages and their mothers. The manipulation was performed daily for the first 21 days of life. As adults, handled (H) rats exhibited attenuated fearfulness (e.g., decreased freezing, increased exploration) in novel environments and a less pronounced increase in the secretion of adrenal glucocorticoids in response to a variety of stressors. These findings clearly demonstrated that the development of rudimentary, adaptive responses to stress could be modified by environmental events. We have followed on these earlier handling studies, convinced that this paradigm provides a marvelous opportunity to examine how subtle variations in the early environment alter the development of specific biochemical systems in the brain, leading to stable individual differences in biological responses to stimuli that threaten homeostasis. In this work we have shown how early handling influences the neurochemical development of certain brain regions that regulate the adrenocortical response to stress. Neonatal handling increases the efficiency of this endocrine response to stress, preventing excessive exposure to the highly catabolic adrenal steroids. In later life, this effect appears to protect the animal from potentially damaging effects of these steroids, ensuring the anatomical integrity of brain structures involved in cognitive functioning.