Visualizing dynamic three-dimensional changes of human reticular dermal collagen under mechanical strain

In clinical practice, plastic surgeons are often faced with large skin defects that are difficult to close primarily. Management of large skin wounds e.g. burns or traumatic lacerations requires knowledge of skin biomechanic properties. Research into skin microstructural adaptation to mechanical deformation has only been performed using static regimes due to technical limitations. Here, we combine uniaxial stretch tests with fast second harmonic generation imaging and we apply this for the first time to investigate dynamic collagen rearrangement in reticular human dermis.Ex vivohuman skin from the abdomen and upper thigh was simultaneously uniaxially stretched while either periodically visualizing 3D reorganization, or visualizing 2D changes in real time. We determined collagen alignment via orientation indices and found pronounced variability across samples. Comparing mean orientation indices at the different stages of the stress strain curves (toe, heel, linear) showed a significant increase in collagen alignment during the linear part of the mechanical response. We conclude that fast SHG imaging during uni-axial extension is a promising research tool for future studies on skin biomechanic properties.

Impact of COVID-19 pandemic on inequalities in mortality: an analysis in Piedmont and Emilia-Romagna

Background

Italy was heavily hit by the COVID-19 pandemic. According to official statistics, during 2020 there were more than 75,000 excess deaths compared to the average expected mortality in 2015-2019. General mortality (GM) is a good measure of both the direct and indirect effects of the pandemic because it's exempt from potential bias due to misclassification of events. Evidence shows a greater burden of disease and mortality attributable to COVID-19 among disadvantaged populations, with the risk of an exacerbation of existing health inequalities. We aim to analyse the trend of social inequalities in mortality during the first pandemic year in two Italian regions (Piedmont and Emilia-Romagna) using data from Administrative Population Registries (APR) and statistical databases.

Methods

Data on deaths occurred between Jan 2015 and Jan 2021 in subjects ≥65, stratified by educational level, were obtained from Regional APR and the Census. Using a time series approach, we computed Standardized Mortality Rates (SMR), Relative Index of Inequalities (RII) and Slope Index of Inequalities (SII), adjusted by age, gender, month and region. SMR, RII and SII from March 2020 were forecasted using Holt-Winters method and compared to the observed values in the same period.

Results

SMRs were higher than expected during the two 2020 epidemic waves (Mar-Apr, Oct-Dec) in both regions. RII didn't increase significantly. Absolute inequalities instead rose in Piedmont during both pandemic waves, mostly among women, and in Emilia-Romagna in March among men.

Conclusions

The impact of the pandemic on inequalities in GM has been at least of the same size of the impact of other mechanisms of unequal mortality. APR coupled with sociodemographic data are a quick and reliable source for assessing the unequal impact of the COVID-19 pandemic on health. Further research is needed to explore mechanisms underlying these effects e.g. inequalities in cause-specific mortality and access to health services.

Key messages

Development of Three Molecular Diagnostic Tools for the Identification of the False Codling Moth (Lepidoptera: Tortricidae)

Three molecular protocols using qPCR TaqMan probe, SYBR Green, and loop-mediated isothermal amplification (LAMP) methods were set up for the identification of larvae and adults of an African invasive moth, Thaumatotibia leucotreta (Meyrick, 1913) (Lepidoptera: Tortricidae). The DNA extracts from larval and adult samples of T. leucotreta were perfectly amplified with an average Ct value of 19.47 ± 2.63. All assays were demonstrated to be inclusive for T. leucotreta and exclusive for the nontarget species tested; the absence of false positives for nontarget species showed a 100% of diagnostic specificity and diagnostic sensitivity for all assays. With the SYBR Green protocol, the Cq values were only considered for values less than 22 (cutoff value) to prevent false-positive results caused by the late amplification of nonspecific amplicons. The limit of detection (LoD) for the qPCR probe protocol was equal to 0.02 pg/µl while a value equal to 0.128 pg/µl for the qPCR SYBR Green assay and LAMP method were established, respectively. The intrarun variabilities of reproducibility and repeatability in all the assays evaluated as CV%, ranged between 0.21 and 6.14, and between 0.33 and 9.52, respectively; the LAMP values were slightly higher than other assays, indicating a very low interrun variability. In order for an operator to choose the most desirable method, several parameters were considered and discussed. For future development of these assays, it is possible to hypothesize the setup of a diagnostic kit including all the three methods combined, to empower the test reliability and robustness.

Life expectancy in the Emilia-Romagna region: an analysis of social and geographical variability

Italy and the Emilia-Romagna region record among the highest life expectancy worldwide. However, differences among geographical areas, social strata and genders have been reported at regional level. The aim of this work is to measure both geographic (among provinces) and social (among education levels) inequalities in life expectancy and to evaluate the association between education and cause-specific mortality, in the Emilia-Romagna region during the period 2012-2016.

The data source is an integrated dataset based on the linkage at individual level of the regional health population register, the mortality register, and the 2011 census; this system of microdata, which is the base of the Emilia-Romagna Longitudinal Study, allows a precise calculation of the person-time at risk. The study population consisted of all individuals who were residents in the Emilia-Romagna region at the 1/1/2012 and took part to the 2011 census.

Life expectancy was estimated through mortality tables reconstructed with a mixed cohort-period approach and combined with the Kannisto's method. Inequalities in mortality were estimated using a longitudinal approach and Poisson models.

Educational disparities were evident even in the Emilia-Romagna region in the early 2010s; life expectancy was shorter among low-educated subjects and the gap varied: 3 years among men and approximately 1.5 years among women. Life expectancy varied also among provinces, although the gaps were smaller and men and women were closer, and there was an indication of an interaction between education and geographical areas. The risk of dying revealed social pattern and disparities were greater for respiratory diseases and for some cancers, particularly among men.

This study is the first attempt to describe, through the Emilia-Romagna Longitudinal Study, educational and geographical disparities in life expectancy in the region and to suggest entry points for actions to tackle these differences.

Key messages

Geographical and social inequalities in life expectancy have been reported at regional level. Those inequalities and the mortality relative risks within Emilia-Romagna during 2012-2016 were estimated. The estimates by the Emilia-Romagna Longitudinal Study highlighted disparities in life expectancy in the Emilia-Romagna region and suggest entry points for actions to tackle these differences.

Norovirus gastroenteritis and seizures: an atypical case with neuroradiological abnormalities

We describe an 8-year-old boy admitted because of prolonged seizures during norovirus gastroenteritis without any signs of encephalopathy. Blood tests were normal and cerebrospinal fluid examination resulted negative for both bacteria and viruses. A reverse transcriptase polymerase chain reaction revealed norovirus RNA in a stool sample. A cerebral computed tomography turned out to be normal whereas subsequent cerebral magnetic resonance imaging showed transitory signal abnormalities consistent with vasogenic edema. The post-ictal electroencephalogram revealed normal background activity with sporadic left posterior delta waves. The child was discharged after 10 days with an unremarkable physical examination. A cerebral magnetic resonance imaging and an electroencephalogram after 1 month were both negative. We report a new case of benign infantile convulsions due to norovirus gastroenteritis with neuroradiological abnormalities to the pertinent literature in order to improve knowledge about this disorder and increase the possibility of clarifying its pathogenesis.

Experimental evidence of signal-optical noise interferencelike effect in underwater amplitude-modulated laser optical radar systems

We report experimental evidence that in an amplitude-modulated laser optical radar system for underwater 3D imaging the observed contrast oscillations as a function of the modulation frequency originate from an interference-like effect between target signal VT and water backscattered radiation VW. The demonstration relies on the ability to perform a direct measurement of VW in a 25 m long test tank. The proposed data processing method enables one to remove the contribution of water backscattering from the detected signal and drastically reduce signal fluctuations due to the medium. Experiments also confirm the possibility to improve the signal to optical noise ratio and contrast by increasing the modulation frequency.

Improvement in underwater phase measurement of an amplitude-modulated laser beam by polarimetric techniques

The phase of the amplitude-modulated radiation reflected by a Lambertian target immersed in water was measured by using a linearly and circularly polarized sounding laser beam. Different values of the water extinction coefficient in the range of 0.06 - 2 m(-1) were realized by adding skim milk as a scattering element. It is shown that very efficient rejection of optical noise, resulting in reliable phase measurements, is accomplished with a cross-polarized and copolarized detection scheme for linear and circular polarization, respectively. The experiment demonstrates that phase measurements are very sensitive to optical noise suppression and that, as far as single scattering is the main involved mechanism, significant improvements can be achieved by adopting a polarization control on both the transmitter and the receiver stages of the apparatus.

Thrombophilic risk factors and unusual clinical features in three Italian CADASIL patients

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetically transmitted cerebrovascular disease. Typically, the first clinical manifestation is migraine and the full clinical spectrum of the disease with recurrent strokes of the subcortical type, cognitive, and mood disorders is seen during the fourth and fifth decades of life. Vascular risk factors are usually absent in CADASIL patients and the diagnosis of the disease is particularly suspected in young adults with cerebrovascular events of unknown cause, diffuse leukoencephalopathy on computed tomography or magnetic resonance imaging, and a history of cerebrovascular diseases or dementia in many family members. We describe three Italian CADASIL patients who presented to medical attention for cerebrovascular events occurred after the age of 55 and had, in addition to hypertension and hyperlipidemia, thrombophilic risk factors such as hyperhomocysteinemia, elevated levels of lipoprotein(a), and antiphospholipid antibodies. Symptoms possibly related to cortical involvement, such as dysphasia and visual field deficits, were reported by two of these patients. We conclude that a diagnosis of CADASIL should not be disregarded in patients with vascular risk factors and presenting with symptoms not immediately referable to subcortical damage at ages more advanced than commonly reported.

Longitudinal evaluation of leukoaraiosis with whole brain ADC histograms

FLAIR and diffusion-weighted MRI were obtained twice (mean interval 20 +/- 4 months) in 10 patients with leukoaraiosis. At follow-up, visual extension of leukoaraiosis was unchanged, whereas the median of whole brain apparent diffusion coefficient (WB-ADC) histogram was increased (p= 0.008) and brain volume index (BVI) was decreased (p = 0.006). WB-ADC histogram and BVI are sensitive to leukoaraiosis and might be considered for monitoring progression of the disease.

Pulmonary function in non-insulin-dependent diabetes mellitus

BACKGROUND

In type I diabetes mellitus, lung function has been investigated in several clinical studies, but there are few data concerning pulmonary function abnormalities in patients with non-insulin-dependent diabetes mellitus (NIDDM).

OBJECTIVES

The aim of this study was to assess the presence of pulmonary function abnormalities in patients with NIDDM and to verify the possible associations between diabetic renal microangiopathy, retinopathy and diabetes control.

METHOD AND PATIENTS

Thirty patients with NIDDM were collected and divided into two similar groups: subjects with retinopathy and/or diabetic glomerulopathy (group 1, n = 15) and patients without any complications (group 2, n = 15). 17 were males and 13 females, aged from 45 to 81 years. They had had diabetes for 3-23 years and were studied at the Division of Internal Medicine, with an outpatient service for diabetic patients. All patients were non-smokers. The presence of diabetic glomerulopathy was determined by measuring the 24-hour protein excretion rate using the nephelometric method. The presence of retinopathy was determined by using ophthalmoscopy. Glycosylated hemoglobin was measured as an indicator of glycemic control. We performed a global spirometry and measured pulmonary diffusion capacity by the single-breath method corrected by alveolar volume.

RESULTS

We found a significant reduction in lung diffusion capacity for carbon monoxide (DL(CO)) in the group of patients with other signs of diabetic microangiopathy (p < 0.005) and a significative correlation between DL(CO )and the grade of albuminuria (r = -0.83, p < 0.001).

CONCLUSIONS

Pulmonary function abnormalities, in particular a reduction in diffusion capacity, are common in patients with NIDDM and signs of diabetic microangiopathy. A possible explanation is related to an impaired pulmonary microvasculature and alveolar epithelial basal lamina.

Performance assessment of new multiplex probe assay for identification of mycobacteria

A new DNA probe assay (INNO LiPA Mycobacteria; Innogenetics, Ghent, Belgium) for the simultaneous identification, by means of reverse hybridization and line-probe technology, of Mycobacterium tuberculosis complex, Mycobacterium kansasii, Mycobacterium xenopi, Mycobacterium gordonae, the species of the Mycobacterium avium complex (MAC), Mycobacterium scrofulaceum, and Mycobacterium chelonae was evaluated on a panel of 238 strains including, besides representatives of all the taxa identifiable by the system, a number of other mycobacteria, some of which are known to be problematic with the only other commercial DNA probe system (AccuProbe; Gen-Probe, San Diego, Calif.), and two nocardiae. The new kit, which includes a control probe reacting with the whole genus Mycobacterium, correctly identified 99.6% of the strains tested; the one discrepancy, which remained unresolved, concerned an isolate identified as MAC intermediate by INNO LiPA Mycobacteria and as Mycobacterium intracellulare by AccuProbe. In five cases, because of an imperfect checking of hybridization temperature, a very slight, nonspecific, line was visible which was no longer evident when the test was repeated. Two strains whose DNA failed amplification at the first attempt were regularly identified when the test was repeated. Interestingly, the novel kit dodged all the pitfalls presented by the strains giving anomalous reactions with AccuProbe. A unique feature of INNO LiPA Mycobacteria is its ability to recognize different subgroups within the species M. kansasii and M. chelonae, while the declared overlapping reactivity of probe 4 with some M. kansasii and Mycobacterium gastri organisms and of probe 9 with MAC, Mycobacterium haemophilum, and Mycobacterium malmoense, may furnish a useful aid for their identification. The turnaround time of the method is approximately 6 h, including a preliminary PCR amplification.

Comparison of Mycobacterium tuberculosis susceptibility testing performed with BACTEC 460TB (Becton Dickinson) and MB/BacT (Organon Teknika) systems

The recently introduced automated culture systems MB/BacT (Organon Teknika, Belgium) was compared with radiometric BACTEC 460TB (Becton Dickinson, USA) to test antimicrobial susceptibility of Mycobacterium tuberculosis to first line drugs. On 113 strains 97.5% agreement was obtained, with the difference being not significant. Concordance was practically complete for the most important drugs, isoniazid and rifampin. The two methods however significantly differed for the time needed to complete the test; in fact MB/BacT required on the average five days more than BACTEC 460TB. Despite the delay in the completion of the test, the excellent reliability along with the elimination of radioactivity and full automation make MB/BacT an attractive alternative for susceptibility testing of M. tuberculosis.

Effects of histamine H3 receptor agonists and antagonists on cognitive performance and scopolamine-induced amnesia

In previous research we found that pre-training administration of histamine H3 receptor agonists such as (R)-alpha-methylhistamine and imetit impaired rat performance in object recognition and a passive avoidance response at the same doses at which they inhibited the release of cortical acetylcholine in vivo. Conversely, in the present study we report that the post-training administration of (R)-alpha-methylhistamine and imetit failed to affect rat performance in object recognition and a passive avoidance response, suggesting that H3 receptor influences the acquisition and not the recall processes. We also investigated the effects of two H3 receptor antagonists, thioperamide and clobenpropit, in the same behavioral tasks. Pre-training administration of thioperamide and clobenpropit failed to exhibit any procognitive effects in normal animals but prevented scopolamine-induced amnesia. However, also post-training administration of thioperamide prevented scopolamine-induced amnesia. Hence, the ameliorating effects of scopolamine-induced amnesia by H3 receptor antagonism are not only mediated by relieving the inhibitory action of cortical H3 receptors, but other mechanisms are also involved. Nevertheless, H3 receptor antagonists may have implications for the treatment of degenerative disorders associated with impaired cholinergic function.

Effect of subchronic treatment with metrifonate and tacrine on brain cholinergic function in aged F344 rats

The effects of 21-day treatment with the acetylcholinesterase inhibitors metrifonate (80 mg kg(-1) per os (p.o.)) and tacrine (3 mg kg(-1) p.o.), twice daily, on cortical and hippocampal cholinergic systems were investigated in aged rats (24-26 months). Extracellular acetylcholine levels were measured by transversal microdialysis in vivo; choline acetyltransferase and acetylcholinesterase activities were measured ex vivo by means of radiometric methods. Basal cortical and hippocampal extracellular acetylcholine levels, measured 18 h after the last metrifonate treatment, were about 15 and two folds higher, respectively, than in control and tacrine-treated rats. A challenge with metrifonate further increased cortical and hippocampal acetylcholine levels by about three and four times, respectively. Basal extracellular acetylcholine levels, measured 18 h after the last treatment with tacrine were not statistically different from those of the control rats. A challenge with tacrine increased cortical and hippocampal extracellular acetylcholine levels by about four and two times. A 75% inhibition of cholinesterase activity was found 18 h after the last metrifonate administration, while only a 15% inhibition was detectable 18 h after the last tacrine administration. The challenge with metrifonate or tacrine resulted in 90 and 80% cholinesterase inhibition, respectively. These results demonstrate that in aging rats a subchronic treatment with metrifonate results in a long-lasting, cholinesterase inhibition, and a persistent increase in acetylcholine extracellular levels which compensate for the age-associated cholinergic hypofunction. Metrifonate is therefore a potentially useful agent for the cholinergic deficit accompanying Alzheimer's disease.

Reticulocytes and reticulated platelets: simultaneous measurement in whole blood by flow cytometry

Reticulated platelets are a fraction of newly released circulating elements characterized by a residual amount of RNA. It has been suggested that the reticulated platelet count, providing an estimate of thrombopoiesis in the same way as erythrocyte reticulocyte count is a measure of erythropoiesis, may be useful in the study of thrombocytopenic disorders. Reticulated red cells and platelets can be analyzed by flow cytometry using specific stains for nucleic acids such as Thiazole Orange and Auramine-O. The aim of our work was to perform the simultaneous evaluation of reticulated elements in whole blood using a standard flow cytometer and to correlate the results obtained with a dedicated cytometer. A group of 14 patients with abnormal absolute reticulocyte counts (range 1.1-11%) and a group of 41 patients showing a platelet discrimination error when analyzed with a dedicated flow cytometer (Sysmex R1000) were enrolled. Linear amplification of both scatter and fluorescence was used to perform reticulocyte count. A gate was set on platelet dimensions, and logarithmic amplification of scatter and fluorescence was used to count reticulated platelets. A good correlation was obtained both for results of reticulocyte count (r2 = 0.9825) and for reticulated platelets (r2 = 0.8717) between our method and those using dedicated instruments. These data show that reticulated platelet count may be easily introduced in clinical laboratories that routinely perform reticulocyte count by flow cytometry.

Acetylcholine release from the frontal cortex during exploratory activity

The activation of the cortical cholinergic system was investigated in 3- and 25-month-old male Wistar rats, by measuring by transversal microdialysis the changes in cortical extracellular acetylcholine (ACh) levels during the performance of simple spontaneous tasks involving exploratory activity and working memory. Two days after implantation of the microdialysis probe in the frontal cortex, object recognition was investigated by either moving the rats from the home cage to the arena containing the objects or keeping the rats in the arena and introducing the objects. Spontaneous alternation was investigated in a Y runway. Young rats discriminated between familiar and novel objects and alternated in the Y runway, while aged rats were unable to discriminate. Whenever rats were moved from the home cage to the arena, ACh release increased (+70-80%) during the exploratory activity. Handling per se had no effect on extracellular ACh levels. When young rats were left in the arena, introduction of the objects caused some exploratory activity and object recognition but no increase in ACh release. ACh release increased by about 300% during spontaneous alternation. In aging rats basal extracellular ACh levels and their increase after placement in the arena were less than half that in young rats. Our work demonstrates that a novel environment activates the cortical cholinergic system, which presumably is associated with arousal mechanisms and selective attentional functions. It also demonstrates that in aging rats the cortical cholinergic hypofunction is associated with a loss of non-spatial working memory.

Tacrine administration enhances extracellular acetylcholine in vivo and restores the cognitive impairment in aged rats

The effect of oral tacrine administration on cortical and hippocampal extracellular acetylcholine (ACh) levels has been investigated by a microdialysis technique, coupled to a HPLC method, in 6- and 22-24-month-old rats. In order to assess whether the increase in extracellular ACh levels was associated with an improvement in the age-related cognitive impairment, the object recognition and step-trough passive avoidance tests were carried out in the treated rats. The extracellular ACh levels measured in the cortex and hippocampus of aged rats without cholinesterase inhibitor in the perfusion Ringer solution were 39 and 54% lower, respectively, than in the young rats. At the dose of 3 mg kg-1, tacrine brought about a three- to four-fold increase in extracellular ACh levels, both in young and aged rats, which peaked 60-80 min after administration and disappeared within the next 60 min. At the same dose, tacrine caused a twofold increase in extracellular ACh levels in the hippocampus of young rats and a sixfold increase in aged rats. The absolute ACh levels at the peak in aged rats were not significantly different from those of young rats. In the object recognition test, aging rats were unable to discriminate between the familiar and novel object. Discrimination was restored by the administration of tacrine at the dose of 1 and 3 mg kg-1, but not 0. 3 mg kg-1 given 30 min before the first trial. Tacrine (3 mg kg-1 p. o.) administered to aging rats before the training trial significantly improved the acquisition of the passive avoidance conditioned response. Our findings demonstrate that tacrine increased both cortical and hippocampal extracellular ACh levels and improved behavioural functions in aged rats.

Effect of metrifonate on extracellular brain acetylcholine and object recognition in aged rats

The effects of metrifonate were investigated in 4-6- and 22-24-month-old rats. Extracellular acetylcholine levels were measured by transversal microdialysis in vivo. Baseline extracellular acetylcholine levels in the cerebral cortex and hippocampus were 42% and 60% lower, respectively, in old than in young rats. Old rats did not discriminate between familiar and novel objects. In old rats, metrifonate (80 mg/kg p.o.) brought about 85% inhibition of cholinesterase activity in the cortex and hippocampus, a 4-fold increase in extracellular acetylcholine levels in the cortex only, and restored object recognition. In young rats, metrifonate caused 75% cholinesterase inhibition in the cerebral cortex and hippocampus, a 2-fold increase in cortical and hippocampal extracellular acetylcholine levels, and no effect on object recognition. The slight cholinesterase inhibition following metrifonate (30 mg/kg) in aged rats had no effect on cortical acetylcholine levels and object recognition. In conclusion, metrifonate may improve the age-associated cholinergic hypofunction and cognitive impairment.

Inhibition of cortical acetylcholine release and cognitive performance by histamine H3 receptor activation in rats

1. The effects of histamine and agents at histamine receptors on spontaneous and 100 mM K(+)-evoked release of acetylcholine, measured by microdialysis from the cortex of freely moving, rats, and on cognitive tests are described. 2. Local administration of histamine (0.1-100 microM) failed to affect spontaneous but inhibited 100 mM K(+)-stimulated release of acetylcholine up to about 50%. The H3 receptor agonists (R)-alpha-methylhistamine (RAMH) (0.1-10 microM), imetit (0.01-10 microM) and immepip (0.01-10 microM) mimicked the effect of histamine. 3. Neither 2-thiazolylethylamine (TEA), an agonist showing some selectivity for H1 receptors, nor the H2 receptor agonist, dimaprit, modified 100 mM K(+)-evoked release of acetylcholine. 4. The inhibitory effect of 100 microM histamine was completely prevented by the highly selective histamine H3 receptor antagonist, clobenpropit but was resistant to antagonism by triprolidine and cimetidine, antagonists at histamine H1 and H2 but not H3 receptors. 5. The H3 receptor-induced inhibition of K(+)-evoked release of acetylcholine was fully sensitive to tetrodotoxin (TTX). 6. The effects of intraperitoneal (i.p.) injection of imetit (5 mg kg-1) and RAMH (5 mg kg-1) were tested on acetylcholine release and short term memory paradigms. Both drugs reduced 100 mM K(+)-evoked release of cortical acetylcholine, and impaired object recognition and a passive avoidance response. 7. These observations provide the first evidence of a regulatory role of histamine H3 receptors on cortical acetylcholine release in vivo. Moreover, they suggest a role for histamine in learning and memory and may have implications for the treatment of degenerative disorders associated with impaired cholinergic function.

Somatostatin infusion suppresses GH secretory burst frequency and mass in normal men

In attempting to elucidate the neuroendocrine mechanisms that regulate pulsatile growth hormone (GH) secretion, we measured serum GH concentrations by an ultrasensitive immunofluorometric method in blood collected every 10 min for 8 h in 11 young healthy male volunteers (age range 21-31 yr) before and during somatostatin (SS) administration (an iv bolus dose of 350 micrograms followed by a continuous infusion at the rate of 6 micrograms.kg-1.h-1, which increases the circulating SS levels to approximately 570 pg/ml). Pulsatile GH secretion was analyzed using the computer-assisted pulse detection program cluster method and deconvolution analysis. The area and frequency of GH peaks were significantly reduced during SS infusion compared with basal values, but detectable pulsatile episodes were still present. These data suggest that, in adult males, SS controls pulsatile GH secretion and can decrease the mass and frequency of GH secretory bursts.

Aniracetam restores object recognition impaired by age, scopolamine, and nucleus basalis lesions

Object recognition was investigated in adult and aging male rats in a two-trials, unrewarded, test that assessed a form of working-episodic memory. Exploration time in the first trial, in which two copies of the same object were presented, was recorded. In the second trial, in which one of the familiar objects and a new object were presented, the time spent exploring the two objects was separately recorded and a discrimination index was calculated. Adult rats explored the new object longer than the familiar object when the intertrial time ranged from 1 to 60 min. Rats older than 20 months of age did not discriminate between familiar and new objects. Object discrimination was lost in adult rats after scopolamine (0.2 mg/kg SC) administration and with lesions of the nucleus basalis, resulting in a 40% decrease in cortical ChAT activity. Both aniracetam (25, 50, 100 mg/kg os) and oxiracetam (50 mg/kg os) restored object recognition in aging rats, in rats treated with scopolamine, and with lesions of the nucleus basalis. In the rat, object discrimination appears to depend on the integrity of the cholinergic system, and nootropic drugs can correct its disruption.

Differential effects of amyloid peptides beta-(1-40) and beta-(25-35) injections into the rat nucleus basalis

The nucleus basalis of male Charles River Wistar rats was injected with 10 micrograms of the beta-amyloid peptides beta-(1-40) and beta-(25-35) and changes in the morphology of the lesioned area, the release of acetylcholine from the cortex, and in behavior were investigated. Injections of saline and a scrambled (25-35) peptide were used as controls. One week after lesioning, a Congo Red-positive deposit of aggregated material was found at the beta-peptides injection site, which lasted for about 21 days in the case of the beta-(25-35) peptide and at least two months for beta-(1-40). No deposit was detected after scrambled peptide injection. At one week post injection, an extensive glial reaction surrounded the injection site of all peptides and saline as well. Such a reaction was still present but rather attenuated after two months. A decrease in the number of cholinergic neurons was detected in the nucleus basalis after one week with all treatments except saline. After two months, a reduction in the number of choline acetyltransferase-immunopositive neurons was still detectable in the rats injected with beta-(1-40) but not in the beta-(25-35)-or scrambled-injected. The reduction in choline acetyltransferase immunoreactivity was closely paralleled by a decrease in basal acetylcholine release from the parietal cortex ipsilateral to the lesion. Disruption of object recognition was observed in the first weeks after beta-(25-35) peptide injection, whereas the beta-(1-40) peptide impaired the performance only two months after lesion. Rats with lesions induced by beta-peptides may be a useful animal model of amyloid deposition for investigation of the pathogenetic mechanisms leading to Alzheimer's disease.

Nerve growth factor increases extracellular acetylcholine levels in the parietal cortex and hippocampus of aged rats and restores object recognition

Male Wistar rats (3- and 20-month-old) were perfused i.c.v. with 1.5 micrograms of either nerve growth factor (NGF) or cytochrome C daily for 14 days. At the end of the infusion, the object-recognition test was carried out and extracellular acetylcholine levels (ACh) were measured in the cortex and hippocampus by transversal microdialysis technique. In 20-month-old control rats, the cortical and hippocampal ACh levels were 35 and 45% lower, respectively, than in 3-month-old rats and the ability to discriminate between a familiar and new object was impared. In the old rats treated with NGF, the ACh release as well as the behavioral performance showed no difference from those of young rats. These findings indicate that both ACh levels and memory impairment are improved in aged rats by NGF treatment and suggest that there is a relationship between object recognition and the activity of the forebrain cholinergic system.

Long-term ethanol consumption by rats: effect on acetylcholine release in vivo, choline acetyltransferase activity, and behavior

The extent and duration of cholinergic hypofunction induced by long-term ethanol consumption was investigated in the rat. Ethanol (20% v/v) was administered to male adult Wistar rats as a sole source of fluid for three or six months. Control rats received tap water. The body weight, food and fluid intake in ethanol-treated rats were lower than in control rats throughout the treatment. After three months of ethanol consumption, and one week withdrawal, acetylcholine release in freely moving rats, investigated by microdialysis technique coupled to high-performance liquid chromatography quantification, was significantly decreased by 57 and 32% in the hippocampus and cortex, respectively, while choline acetyltransferase activity was significantly decreased (-30%) only in the hippocampus. A complete recovery of choline acetyltransferase activity and acetylcholine release was found after four ethanol-free weeks. Conversely, after four weeks of withdrawal following six months of ethanol treatment, the recovery in acetylcholine release was not accompanied by that in choline acetyltransferase activity, which remained significantly lower than in control rats in both cortex and hippocampus. The ability of rats to negotiate active and passive avoidance conditioned response tasks, tested after four ethanol-free weeks, was strongly impaired in both three- and six-month ethanol-treated rats. In conclusion, our experiments demonstrate that the development of a long-lasting cholinergic hypofunction requires at least six months of ethanol administration. The hypofunction affects choline acetyltransferase activity and acetylcholine release differently, and undergoes a remarkable recovery.

Effect of scopolamine and nootropic drugs on rewarded alternation in a T-maze

The effects of different doses of scopolamine, and of the nootropic drugs oxiracetam and aniracetam, were investigated on the performance of male Wistar rats in a T-maze requiring a spatial discrimination in the stem (reference memory) and an alternate discrimination in the arms (working memory). Criterion (90% correct responses) was reached within 3 days of daily training for stem and 9 days for arm discrimination. Scopolamine (0.1, 0.2, 0.6, and 1.0 mg/kg, SC, 60 min before session) significantly impaired working memory, as shown by a decrease in the number of correct alternations, without affecting reference memory. Both nootropic drugs (25-50 and 100 mg/kg PO) 30 min before scopolamine) attenuated the working memory impairment induced by scopolamine.

GM1 ganglioside counteracts cholinergic and behavioral deficits induced in the rat by intracerebral injection of vincristine

The intracerebroventricular injection of 0.5 mg of vincristine sulphate in adult male Wistar rats caused within 11 days the impairment of motor and reflexive behavior, evaluated by the elevated platform and hanging wire tests, a decrease in food consumption and loss of body weight, a 45% decrease in hippocampal choline acetyltransferase (ChAT) activity and a 35% decrease in the rate of high-affinity choline uptake (HACU) in the injected side. The latter effects are due to the death of neurons in the respective hemiseptum. Intrafimbrial injection of vincristine caused the same decrease in ChAT activity without behavioral alterations. Daily i.p. administration of GM1 ganglioside, beginning immediately after the vincristine injection, prevented dose dependently the decrease in ChAT activity and HACU rate. Prevention was complete with the 60 mg/kg dose. The same dose was equally active on ChAT activity when given s.c. but was inactive p.o. The ChAT decrease was also prevented when GM1 treatment began 5 days after vincristine. GM1 60 mg/kg i.p. also reduced the behavioral toxicity of vincristine. The possibility that GM1 might prevent vincristine toxicity by antagonizing its disruption of neurofilaments and axonal flow is discussed.

Unilateral and bilateral nucleus basalis lesions: differences in neurochemical and behavioural recovery

The neurochemical and behavioural recovery following unilateral and bilateral lesions of the nucleus basalis was investigated in adult male Wistar rats 20 days and 6 months after surgery. The lesions were made by stereotaxic injections of ibotenic acid. Twenty days after surgery there was a statistically significant choline acetyltransferase decrease in the frontal and parietal ipsilateral cortex of the unilaterally lesioned rats and in the cortex of both hemispheres after bilateral lesions. Cortical high affinity choline uptake rate was significantly decreased 4 days after lesions but showed a rapid recovery within 20 days post-lesion in unilaterally and bilaterally lesioned rats. However, at this time both groups of lesioned rats showed a marked impairment in the acquisition of passive and active (shuttle-box) avoidance conditioned responses. Six months after surgery the decrease in choline acetyltransferase activity was smaller and statistically significant in the ipsilateral frontal cortex only in the unilaterally lesioned rats and in the frontal and parietal cortex of both hemispheres in the bilaterally lesioned rats. High affinity choline uptake was increased in the contralateral hemispheres of the unilaterally lesioned rats and was significantly larger than in the bilaterally lesioned rats. There was no difference in the acquisition of both passive and active avoidance conditioned responses between the sham operated and unilaterally lesioned rats, while the bilaterally lesioned rats could only negotiate the active avoidance conditioned response. In conclusion, our experiments demonstrate a remarkable neurochemical and behavioural recovery within 6 months in rats with a unilateral lesion of the nucleus basalis and only a limited recovery in the bilateral lesioned rats.

Effects of ganglioside treatment in rats with a lesion of the cholinergic forebrain nuclei

The effects of GM1 ganglioside (30 mg/kg i.p.) administration for 22 days on choline acetyltransferase (ChAT) activity and noradrenaline (NA) levels in the cerebral cortex and on the acquisition of active and passive avoidance-conditioned responses were investigated in both sham-operated rats and in rats with a unilateral electrolytic lesion of the magnocellular forebrain nuclei (MFN). A statistically significant ChAT decrease in cortical areas ipsilateral to the lesion was found in saline-treated lesioned rats. In the lesioned GM1-treated rats, ChAT activity was only reduced in the frontoparietal areas and was significantly increased in the ipsilateral parietooccipital areas as well as in both contralateral regions. NA levels in the cortex were neither significantly affected by the lesion nor by GM1 treatment. The lesion impaired the acquisition of active and passive conditioned avoidance responses. GM1 treatment improved acquisition of the active avoidance response in the lesioned rats as indicated by a larger number of avoidances and a smaller number of escape failures during training in comparison with saline treatment. Ganglioside had no effect on the passive avoidance responses. These results demonstrate that GM1 administration facilitates the recovery of the cortical cholinergic system and of behavioral responses impaired by an electrolytic lesion of the cholinergic forebrain nuclei.

Lesions of cholinergic forebrain nuclei: changes in avoidance behavior and scopolamine actions

The acquisition of active (shuttle-box) and passive avoidance conditioned responses and the effects of scopolamine on acetylcholine (ACh) output in freely moving rats and on conditioned responses were investigated 20 days after placing a unilateral lesion in the magnocellular forebrain nuclei (MFN). In the lesioned rats spontaneous ACh output from the cerebral cortex ipsilateral to the lesion was slightly decreased, while on the other hand the increase in ACh output elicited by scopolamine was strongly reduced. Sham operated rats always performed more active avoidance responses than MFN lesioned rats in the daily training shuttle-box sessions, and the facilitating effect of scopolamine (1 mg/kg IP) on the shuttle-box performance was suppressed. However the lesion did not disrupt the shuttle-box performance whenever training had taken place before the lesion. In the lesioned rats retested 30 min after the training trial, an impairment of the passive avoidance response was found. The effect of the lesion was potentiated by scopolamine. The results show therefore that MFN lesions impair the cortical cholinergic mechanisms, whose activity seems to play an important role in cognitive functions.

A possible mechanism for cholesteryl ester formation during demyelination: lecithin:cholesterol acyltransferase (LCAT) activity in rat brain

Lecithin:cholesterol acyltransferase (LCAT) activity has been examined in the rat by using a brain homogenate preparation as the phospholipid substrate and blood plasma as the enzyme source. LCAT activity was detected on using 60 mul of serum onwards. Successive experiments have also shown that LCAT activity is present in the edematous rat brain tissue homogenate when incubated with inactivated rat plasma as substrate. The results are discussed in relation to cholesteryl ester accumulation in brain during demyelinating diseases.