Regulation of cholesterol metabolism: New players for an old physiological process

Identified more than two centuries ago, cholesterol plays a pivotal role in human physiology. Since cholesterol metabolism is a physiologically significant process, it is not surprising that its alterations are associated with several pathologies. The discovery of new molecular targets or compounds able to modulate this sophisticated metabolism has been capturing the attention of research groups worldwide since many years. Endogenous and exogenous compounds are known to regulate cellular cholesterol synthesis and uptake, or reduce cholesterol absorption at the intestinal level, thereby regulating cholesterol homeostasis. However, there is a great need of new modulators and diverse new pathways have been uncovered. Here, after illustrating cholesterol metabolism and its well-known regulators, some new players of this important physiological process are also described.

Long-Lasting Impact of Sugar Intake on Neurotrophins and Neurotransmitters from Adolescence to Young Adulthood in Rat Frontal Cortex

The detrimental impact of fructose, a widely used sweetener in industrial foods, was previously evidenced on various brain regions. Although adolescents are among the highest consumers of sweet foods, whether brain alterations induced by the sugar intake during this age persist until young adulthood or are rescued returning to a healthy diet remains largely unexplored. To shed light on this issue, just weaned rats were fed with a fructose-rich or control diet for 3 weeks. At the end of the treatment, fructose-fed rats underwent a control diet for a further 3 weeks until young adulthood phase and compared with animals that received from the beginning the healthy control diet. We focused on the consequences induced by the sugar on the main neurotrophins and neurotransmitters in the frontal cortex, as its maturation continues until late adolescence, thus being the last brain region to achieve a full maturity. We observed that fructose intake induces inflammation and oxidative stress, alteration of mitochondrial function, and changes of brain-derived neurotrophic factor (BDNF) and neurotrophin receptors, synaptic proteins, acetylcholine, dopamine, and glutamate levels, as well as increased formation of the glycation end-products Nε-carboxymethyllysine (CML) and Nε-carboxyethyllysine (CEL). Importantly, many of these alterations (BDNF, CML, CEL, acetylcholinesterase activity, dysregulation of neurotransmitters levels) persisted after switching to the control diet, thus pointing out to the adolescence as a critical phase, in which extreme attention should be devoted to limit an excessive consumption of sweet foods that can affect brain physiology also in the long term.

Long-lasting impact of perinatal dietary supplementation of omega 3 fatty acids on mevalonate pathway: potential role on neuron trophism in male offspring hippocampal formation

Objective: We were aimed at evaluating the long-term impact of perinatal an omega-3 fatty acid-enriched diet on the mevalonate/cholesterol pathway in the brain of male offspring.Methods: Female rats were fed with standard or omega-3 fatty acid-enriched diet during pregnancy and lactation. Liver, brain and plasma were collected from infant, adolescent and adult male offspring for subsequent biochemical and morphological analyses.Results: The omega-3 enriched diet induced region-dependent changes of the 3-hydroxy 3-methylglutaryl Coenzyme A reductase in the brain and affected notably RhoA/CREB signaling and the nerve growth factor content in the hippocampus. Our data reveal a long-lasting impact of perinatal omega-3 fatty acid supplementation on hippocampal nerve growth factor levels mediated by reduced 3-hydroxy 3-methylglutaryl Coenzyme A reductase activation state and enhanced CREB signaling.Discussion: These data underline the importance of the perinatal omega-3 enriched diet for adult brain function and reveal a new pathway important for nerve growth factor regulation.

Serological biomarkers of zearalenone exposure in beef heifers receiving anti-mycotoxin additive

The inclusion of anti-mycotoxin additives (AMA) in the diet of production animals has been widely used to avoid mycotoxin exposure. In order to confirm the efficacy of such products in vivo, measurement of mycotoxins and/or their metabolites in biological fluids is preconized. This study aimed at determining the serological biomarkers of zearalenone (ZEN), α-zearalenol, β-zearalenol, α-zearalanol, β-zearalanol (β-ZAL) and zearalanone, to evaluate the efficacy of an AMA in beef heifers. The trial lasted 37 days: 11 days of adaptation, 21 days of actual experiment, and 5 days of regression. Twenty-four heifers were randomly assigned to receive one of the following treatments (n=6/group): (T1) basal diet (control); (T2) basal diet + 5 mg/kg of ZEN; (T3) basal diet + 5 mg/kg of ZEN + 2.5 kg/t of AMA; and (T4) basal diet + 5 mg/kg of ZEN + 5.0 kg/t of AMA. Blood sampling was performed on different days after the diet was given. The samples were centrifuged to obtain the blood serum, and then analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). β-ZAL was detected above the limit of quantification both in the unconjugated (>0.60 ng/ml) and conjugated (>0.90 ng/ml) forms. The remaining metabolites presented concentrations under the limit of detection. In the efficacy evaluation of the AMA, there was no significant difference (P>0.05) between the treatments with and without additive at the tested levels of inclusion. Thus, β-ZAL may be employed as a biomarker of ZEN exposure via diet to evaluate the efficacy of an AMA through serological parameters. The technique applied in this study proved to be an adequate alternative for in vivo confirmation of the efficacy of products in adsorbing the toxin.

Prenatal Exposure to BPA: The Effects on Hepatic Lipid Metabolism in Male and Female Rat Fetuses

Bisphenol A (BPA) is an organic chemical compound widely used for manufacturing plastics. BPA exposure originates principally from the diet, but it can also originate from dermal contact. In over 90% of individuals, including pregnant women, BPA is detectable in several body fluids. The effects of this exposure on the fetus are under active investigation in several research laboratories. The aim of our work was to study the impact of prenatal exposure to BPA in the liver of rat fetuses from a sex-dependent point of view. We particularly investigated the effects of prenatal BPA exposure on hepatic lipids because of their crucial role, not only for the liver, but also for the whole-body functions. Our results demonstrate that the liver of rat fetuses, in utero exposed to a very low dose of BPA (2.5 µg/kg/day), displays significant modulations with regard to proteins involved in cholesterol and fatty acid biosynthesis and trafficking. Moreover, an impact on inflammatory process has been observed. All these effects are dependent on sex, being observable only in female rat fetuses. In conclusion, this work demonstrates that maternal exposure to BPA compromises hepatic lipid metabolism in female offspring, and it also reveals the perspective impact of BPA on human health at doses currently considered safe.

Effects of Late-Life Caloric Restriction on Age-Related Alterations in the Rat Cortex and Hippocampus

Background: A major problem of aging is the disruption of metabolic homeostasis. This is particularly relevant in the brain where it provokes neurodegeneration. Caloric restriction is a physiologic intervention known to delay the deleterious consequences of aging in several species ranging from yeast to mammals. To date, most studies on experimental models have started this dietary intervention from weaning, which is very difficult to be translated to human beings. Here, we study the effects of a more realistic dietary regimen in rats, starting at an advanced age and lasting for six months. Methods: we analyzed in the cortex and hippocampus, the proteins involved in the energetic balance of the cells, cholesterol metabolism, oxidative stress response, inflammation, synaptic impairment, and brain trophism. Results: our results suggest that caloric restriction in late life can revert only some age-related changes studied here.

Laparoscopic surgery for benign adnexal conditions under spinal anaesthesia: Towards a multidisciplinary minimally invasive approach

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In general surgery locoregional anaesthesia increased laparoscopy advantages.

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28 women submitted to gynaecological laparoscopy for benign adnexal conditions.

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13 patients under spinal anaesthesia, 15 under general anaesthesia.

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Less postoperative pain and reduced need f opioids in the spinal anaesthesia arm.

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Earlier mobilization and return of bowel function in the spinal anaesthesia arm.

Background

Laparoscopic gynaecological surgery is commonly performed under general anaesthesia with endotracheal intubation. In general surgery, locoregional anaesthesia was applied to laparoscopic procedures, increasing minimally invasive surgery advantages.

Aims

To assess and compare postoperative pain after laparoscopic adnexal procedures for benign conditions under spinal anaesthesia (SA) versus general anaesthesia (GA). Furthermore, anaesthesiologic, surgical and clinical data were evaluated in both groups.

Materials and Methods

This is a prospective cohort study performed in a tertiary level referral centre for minimally invasive gynaecological surgery (Gynaecology and Human Reproduction Physiopathology, University of Bologna). Women scheduled for adnexal laparoscopic surgery for benign conditions between February and May 2019 were assigned to receive either SA or GA with endotracheal intubation. A sample size of 13 women per group was needed to detect a 2-point difference in pain scores.

Main findings

13 women were enrolled in the SA arm, 15 in the GA arm. In the SA cohort, the most common intraoperative adverse event was shoulder pain, reported by 3/12 women. At 1, 8, 12, 24 and 48 h after surgery pain was significantly lower in the SA arm (p < .05). Patients submitted to SA experienced no need for opioid drugs administration, unlike those receiving GA. Patients’ mobilization and return of bowel function were noted significantly earlier in the SA group (p < .05).

Conclusions

SA is a feasible, safe and effective anaesthesiologic technique for laparoscopic gynaecological procedures for benign conditions, allowing a better control of postoperative pain. Women undergoing SA achieve earlier mobilization and bowel canalization. During the Covid-19 pandemics, SA could be useful in reducing the need for invasive procedures on respiratory tract.

Inhibition of Bromodomain and Extraterminal Domain (BET) Proteins by JQ1 Unravels a Novel Epigenetic Modulation to Control Lipid Homeostasis

The homeostatic control of lipid metabolism is essential for many fundamental physiological processes. A deep understanding of its regulatory mechanisms is pivotal to unravel prospective physiopathological factors and to identify novel molecular targets that could be employed to design promising therapies in the management of lipid disorders. Here, we investigated the role of bromodomain and extraterminal domain (BET) proteins in the regulation of lipid metabolism. To reach this aim, we used a loss-of-function approach by treating HepG2 cells with JQ1, a powerful and selective BET inhibitor. The main results demonstrated that BET inhibition by JQ1 efficiently decreases intracellular lipid content, determining a significant modulation of proteins involved in lipid biosynthesis, uptake and intracellular trafficking. Importantly, the capability of BET inhibition to slow down cell proliferation is dependent on the modulation of cholesterol metabolism. Taken together, these data highlight a novel epigenetic mechanism involved in the regulation of lipid homeostasis.

Loss of Mevalonate/Cholesterol Homeostasis in the Brain: A Focus on Autism Spectrum Disorder and Rett Syndrome

The mevalonate (MVA)/cholesterol pathway is crucial for central nervous system (CNS) development and function and consequently, any dysfunction of this fundamental metabolic pathway is likely to provoke pathologic changes in the brain. Mutations in genes directly involved in MVA/cholesterol metabolism cause a range of diseases, many of which present neurologic and psychiatric symptoms. This raises the question whether other diseases presenting similar symptoms are related albeit indirectly to the MVA/cholesterol pathway. Here, we summarized the current literature suggesting links between MVA/cholesterol dysregulation and specific diseases, namely autism spectrum disorder and Rett syndrome.

Prenatal exposure to valproate induces sex-, age-, and tissue-dependent alterations of cholesterol metabolism: Potential implications on autism

Here, we investigated the protein network regulating cholesterol metabolism in the liver and brain of adolescent and adult male and female rats prenatally exposed to valproate (VPA), a well validated experimental model of autism spectrum disorders (ASD). We were aimed at studying whether prenatal VPA exposure affected the proteins involved in cholesterol homeostasis in a sex-dependent manner. To this aim the protein network of cholesterol metabolism, in term of synthesis and plasma membrane trafficking, was analyzed by western blot in the liver and different brain areas (amygdala, cerebellum, cortex, hippocampus, nucleus accumbens, and dorsal striatum) of adolescent and adult male and female rats prenatally exposed to VPA. Our results show that physiological sex-dependent differences are present both in the liver and in brain of rats. Interestingly, VPA affects specifically the brain in an age- and region-specific manner; indeed, cerebellum, cortex, hippocampus and nucleus accumbens are affected in a sex-dependent way, while this does not occur in amygdala and dorsal striatum. Overall, we demonstrate that each brain area responds differently to the same external stimulus and males and females respond in a different way, suggesting that this could be related to the diverse incidences, between the sexes, of some neurodevelopmental pathologies such as autism, which displays a 3:1 male to female ratio.

Frovatriptan for The Prevention of Postdural Puncture Headache

Efficacy of 5–day treatment with oral frovatriptan 2.5 mg/die for the prophylaxis of post-dural puncture headache (PDPH) was tested in 50 in-patients. A mild headache occurred in 7 (14%) patients for a total of 9 days (p < 0.01 vs. no-PDPH). Most episodes of PDPH occurred in the first days of treatment (only 1 patient had headache at dismissal): 5 patients had only 1 episode, while 2 had headache for 2 consecutive days. No other symptoms were recorded. Occurrence of PDPH in a subgroup of 6 (12%) patients previously submitted to a diagnostic lumbar puncture was also examined: 4 of them reported a PDPH on the previous lumbar puncture in absence of triptans. In only 1 of these 4 patients PDPH recurred under treatment with frovatriptan. In conclusion, our non-randomized open-label study suggests efficacy of oral frovatriptan for PDPH prevention. These results need to be confirmed in a randomized, controlled, double-blind study.

Sex pheromone components of the European goat moth,Cossus cossus

Female tip washings of the European goat moth,Cossus cossus L., were found to contain the following compounds that are structurally similar to known pheromone components of Lepidoptera (%): decyl acetate (1.5), (Z)-5-dodecenol (1), (Z)-5-dodecenyl acetate (66), dodecyl acetate (12), (Z)-5-tetradecenyl acetate (14), tetradecyl acetate (4), and hexadecyl acetate (1.5). The washes contained an average of 125 ng of (Z)-5-dodecenyl acetate per female equivalent. EAG responses to nanogram amounts of the identified products indicated that (Z)-5-dodecenyl acetate was the most potent olfactory stimulant followed by (Z)-5-tetradecenyl acetate and (Z)-5-dodecenol, whereas the saturated acetates caused only weak depolarization. A strong EAG response was also recorded for (Z)-3-decenyl acetate, which was not detected in the female tip washings. Field results showed that (Z)-5-dodecenyl acetate was essential for the attraction of the males and that (Z)-3-decenyl acetate improved the attractiveness of (Z)-5-dodecenyl acetate alone or in combination with (Z)-5-tetradecenyl acetate.

Frequency of headaches in patients over 80. A preliminary report

We evaluated 44 old patients (mean age 84 years) in order to study the frequency of headaches. The frequency found in our sample is higher in comparison to other studies. Further studies including a larger number of patients are needed to obtain more incisive results.

Predictors of epilepsy surgery outcome: a meta-analysis

The potential efficacy of temporal and extratemporal resection in patients with partial epilepsy uncontrolled by anti-epileptic drugs is undisputed. However, there are still uncertainties about which patients will benefit most. A systematic review of the available literature has been undertaken by four pairs of reviewers to assess the overall outcome of epilepsy surgery and to identify factors better correlated to seizure outcome. A Medline search for studies on epilepsy surgery published since 1984 was performed. Studies were included if they had a well-defined population and design, a sample size of at least 30 patients, an MRI performed in least 90% of cases, an expected duration of follow-up of at least one year, and a post-operative outcome measured as seizure remission. A good outcome was considered as seizure control or seizure-free status for at least one year or Engel class I. Based on the review of 47 articles meeting all the eligibility criteria, febrile seizures (odds ratio, OR, 0.48; 95% confidence interval, CI, 0.27-0.83), mesial temporal sclerosis (OR 0.47; 95% CI 0.35-0.64), tumors (OR 0.58; 95% CI 0.42-0.80), abnormal MRI (OR 0.44; 95% CI 0.29-0.65), EEG/MRI concordance (OR 0.52; 95% CI 0.32-0.83), and extensive surgical resection (OR 0.24; 95% CI 0.16-0.36) were the strongest prognostic indicators of seizure remission (positive predictors); by contrast, post-operative discharges (OR 2.41; 95% CI 1.37-4.27) and intracranial monitoring (OR 2.72; 95% CI 1.60-4.60) predicted an unfavorable prognosis (negative predictors). Firm conclusions cannot be drawn for extent of resection, EEG/MRI concordance and post-operative discharges for the heterogeneity of study results. Neuromigrational defects, CNS infections, vascular lesions, interictal spikes, and side of resection did not affect the chance of seizure remission after surgery. Despite a number of limitations, the results of the review provide some insight into the selection of the best surgical candidates in clinical practice but raise concerns on the quality of published reports, and may serve as the basis for the identification of better standards to assess surgical outcome in observational studies.

Chronic alcohol use and first symptomatic epileptic seizures

OBJECTIVE

To establish whether chronic alcoholism and alcohol consumption are risk factors for developing a first symptomatic epileptic seizure.

METHODS

Multicentre case-control study of 293 patients (160 men, 133 women) with a first seizure symptomatic (either acute or remote) of head trauma, stroke, or brain tumour, matched to 444 hospital controls for centre, sex, age (+/-5 years), and underlying pathology.

RESULTS

The risk of first seizure in alcoholics was no higher than in non-alcoholics for men (odds ratio 1.2, 95% confidence interval 0.4 to 3.2) or women (1.5, 0.1 to 54.4). The odds ratio (both sexes) was 1.2 (0.8 to 1.7) for an average intake of absolute alcohol of 1-25 g/day, 0.9 (0.5 to 1.5) for 26-50 g/day, 1.6 (0.8 to 3.0) for 51-100 g/day, and 1.4 (0.5 to 3.5) for >100 g/day.

CONCLUSIONS

We found no evidence of an association between alcohol use or alcoholism and a first symptomatic seizure.

Airway management in an infant with congenital centrofacial dysgenesia

The use of a laryngeal mask airway (LMA) on two occasions, in a 53-day-old and 270-day-old male infant with Tessier N.3 and N.4 facial defects, using sedation and topical anaesthesia is described. The LMA was used to manage the airway and facilitate inhalation induction of anaesthesia as the facial deformities were thought to be too extensive for the safe use of a facemask. The LMA is an alternative to a facemask and secures the airway and facilitates the inhalation induction of anaesthesia in paediatric patients with severe facial deformities.

Anaesthesia for laparoscopic surgery in paediatrics

Laparoscopic surgery is an emerging procedure in the treatment of many surgical pathologies. Laparoscopy in the paediatric patient reduces surgical trauma and improves cosmetic RESULTS. Physiological changes during laparoscopic surgery are mainly related to the increased intra-abdominal pressure (IAP) associated with CO2 insufflation of the abdomen, the patient's postural modifications (head-up or head-down) and CO2 absorption and its general effects. Increases in IAP affect both ventilation and circulation. Increased IAP induces a mechanical compression of the diaphragm that reduces pulmonary compliance, vital capacity, functional residual capacity (FRC) and total lung volume. Pneumoperitoneum in children has a major impact on cardiac volumes and function, mainly through the effect on ventricular load conditions. The acute increase in IAP affects both preload and afterload, while the systolic cardiac performance remains unchanged. During anaesthesia for videolaparoscopy it is important not to exceed an intrabdominal pressure of 6 mmHg in newborns and infants and 12 mmHg in older children. In our clinical experience the respiratory, cardiocirculatory and temperature parameters have been slightly influenced during laparoscopy, but have always been maintained within the normal ranges. Laparoscopic videosurgery in newborns, infants and paediatric age group patients can be performed safely and with satisfactory clinical results.

The Cochrane collaboration in neurology: acquisitions, research, and new initiatives

The Cochrane Collaboration (CC) is an international organization involving 16 national centers around the world, set up in response to the need for collecting all randomized controlled trials on health care interventions, with the aim of facilitating and coordinating the preparation, maintenance and dissemination of periodic systematic reviews of these trials. These are prepared by Collaborative Review Groups (CRGs) working together in an area of common interest under the guidance of an editorial team, supported by national Cochrane centers. Nine CRGs are involved in each neurological field, with more than 300 reviewers and members of editorial teams. For a review to be called a 'Cochrane review', it must be structured in the format outlined in the Cochrane Handbook. It is then published and disseminated through the Cochrane Database of Systematic Reviews (CDSR) in the Cochrane Library (CL). Each Cochrane review is prepared using the Review Manager software distributed to CRGs by CC. The editorial team is responsible for assembling an edited module of reviews prepared by CRGs for incorporation and dissemination using electronic media through the CDSR located in the CL. The CL contains information about the CC and 4 other databases: the Database of Abstracts of Reviews of Effectiveness, the Cochrane Controlled Trials Register, the Cochrane Review Methodology Database and the NHS Economic Evaluation Database. The authors use an example of Cochrane reviews about cerebrovascular disorders to illustrate that the CL is a powerful source of evidence for answering clinical questions and providing information as a basis for therapeutic decisions, for the improvement of neurological practice. A new initiative, the Cochrane Neurological Network, has recently been set up with the aim of improving communication among neurological CRGs, and between them and health care professionals interested in neurological diseases so as to update neurologists on the activity of the CC.

[Latex allergy in pediatric age: an interdisciplinary perioperative management and case reports]

BACKGROUND

Latex intraoperative allergy is more and more frequent, especially in at groups risk (patients with spina bifida or congenital genitourinary abnormalities, pluri-operated patients, atopic subjects) and in pediatric age. The main problem of this allergy consists in the necessity of a strict collaboration of many specialists, in order to identify and safeguard the patient.

METHODS

Our experience has pointed out an interdisciplinary perioperative management able to: 1. identify patients affected by latex allergy; 2. submit them to a latex-safe perioperative proceeding; 3. check their conditions with periodical tests. Selecting patients through a history and a list of questions, identifying profiles of typical risk patients, organizing the operating room with latex-free materials and equipment were the most important issues. Since November 1997 to December 1999 eighteen latex-safe perioperative proceedings have been carried out on 8 subjects (2 with esophageal atresia, 4 with bladder exstrophy and 2 with cloacal exstrophy); 2 of them were emergency cases.

RESULTS

No allergic reactions and no proceeding-linked complications have been registered. Operators have always been satisfied by materials and equipment. Anesthesiological and surgical times resulted equal to those without latex-safe management.

CONCLUSIONS

This perioperative management of potential or verified latex allergic patients turned out to be valid, safe and easy in practical application.

[Problems in anesthesia in pulmonary cystic adenomatosis]

Congenital cystic adenomatoid malformation (CCAM) of the lung is a rare disease. It is about an abnormal proliferation of mesenchymal elements and failure of maturation of bronchiolar structures, characterized by the replacement of normal pulmonary tissue with "cysts" in variable size and number. These lesions communicate with the tracheobronchial tree. During fetal period hydrops and polyhydramnios can be associated with CCAM. A cystic adenomatoid malformation can be detected by antenatal ultrasound, and, at the birth, it is confirmed by chest radiography. From January 1990 to December 1998, 24 cases with CCAM came to our observation; 16 of these patients underwent surgery and 14 have come to a complete recovery. The newborns, with CCAM, can show early acute respiratory distress for rapid expansion of the cysts leading to compression of normal lung and mediastinal shift. Conventional mechanical ventilation may cause further expansion of the involved lobe with a ball-valve effect: this take a clinical deterioration. Perioperative ventilatory management with high frequency oscillation (HFO) is useful to stabilize and to improve arterial blood gases of this patients. At the moment, thanks to the early prenatal sonographic diagnosis, it is possible, and strongly advisable, after adequate serial checkings during the pregnancy, to refer CCAM cases to a tertiary centre that is properly equipped, where a poly-specialist team consisting of obstetrician, neonatologist, pediatric anesthetist and pediatric surgeon, will be able to plan and arrange in the best treatment necessary for the newborn.

[Electroencephalographic changes during anesthesia with low-dose propofol]

The electroencephalographic changes of 12 patients submitted to anaesthesia with low dosages of propofol (4-2 mg/kg/h + fentanyl) for peripheral vascular surgery have been studied. The standard induction dose of propofol was 2 mg/kg for all the patients. The EEG recording was carried out during the whole length of anaesthesia and the EEG changes were analysed during induction and maintenance phases. During surgical anaesthesia it was always easy to read EEG and also to detect eventual cerebral suffering. On the basis of our results we can suggest this anesthesiologic technique for surgery (for example: carotid surgery) requiring a continuous monitoring of the cerebral function during intra and postoperative phases.

Multiple forms of protein kinase from normal human brain and glioblastoma

The biochemical characteristics of the protein kinase (PK; adenosine triphosphate-protein phosphotransferase, EC 2.7.1.37) isozymes in subcellular preparations from normal human brain cortex and glioblastoma were investigated after chromatography on diethylaminoethyl cellulose, and the following results have been obtained. Two major isozyme forms, eluted by 50 and 200 mM phosphate buffer, are present in both cytosol and membrane-derived preparations from cerebral cortex. Furthermore, these isozyme forms have properties similar to those referred to as type I and type II cyclic adenosine 3':5'-monophosphate-dependent PK. In these chromatographic isozymes, cyclic adenosine 3';5'-monophosphate is more active in stimulating the basal PK enzyme than is cyclic guanosine 3':5'-monophosphate. In glioblastoma, the PK activity from cytosol and particulate preparations is resolved by diethylaminoethyl cellulose in four peaks. In cytosol, the major portion of the enzyme is eluted with a 300 mM buffer (about 50% of the total basal PK activity) and is cyclic nucleotide dependent. On the contrary, in glioblastoma particulate, the PK enzyme is mainly eluted at 50 and 100 mM buffer; neither of these isozymes is cyclic nucleotide dependent. As for cytosol, only the particulate isozyme eluted at 300 mM buffer is strongly activated by cyclic nucleotides. Finally, in both glioblastoma subcellular preparations, only a type II cyclic adenosine 3':5'-monophosphate-dependent PK is present.

Characteristics of the cyclic AMP-phosphodiesterase activator in human brain tumours

The levels of the cyclic adenosine 3',5'-monophosphate (cyclic AMP)-phosphodiesterase (PDE) and the biochemical properties of its endogenous protein activator (PDEA) obtained from the human brain cortex and from different types of human cerebral tumours have been evaluated. The effects of the various PDEAs were studied measuring the activation of an activator-depleted cyclic AMP-PDE prepared from a normal brain cortex. The PDEA, obtained from normal and pathological tissues, did not change the affinity of the purified PDE for cyclic AMP, while it increased the Vmax of the enzyme. On the other hand, a cross-activation study showed that the PDEA lacked tissue specificity and was present in the tissue in excess over the enzyme. The levels of cyclic AMP-PDE and PDEA were much higher in normal than in tumoural tissues. The enzyme activity decreased in cerebral tumours more markedly than the protein activator. This biochemical pattern was more evident in the tumours of glial origin which are the most malignant.

Characterization of protein kinase system in human skeletal muscle

The properties and distribution of basal and cyclic nucleotide stimulated protein kinases have been studied in normal and diseased human muscles. In particulate fraction of muscles from neurogenic atrophy the PK activity is remarkably lower than in control tissues, whereas in the cytosol of the same tissues an increase of enzyme activity was observed. In Duchenne dystrophy the PK activities were slighly lower than in controls both in particulate and in soluble fractions. The authors suggest that the altered subcellular distribution found in neurogenic atrophy might be due to the loss of nerve trophic control.

Basal, cAMP- and cGMP-dependent protein kinases in human brain tumors

Since the effects of cyclic nucleotides are mediated via protein kinases activation, we have studied the properties and regulation of these enzymes in cytosol and particulate fraction of normal cerebral tissues and of some human brain tumors. We found that distribution and activity of cyclic nucleotide-dependent protein kinases are regulated differently among various brain tumors and in comparison to normal gray and white matter. Pathological tissues show an higher cGMP-dependent protein kinase and this biochemical pattern is particularly evident in tumors with more pronounced malignancy. These data further confirm the hypothesis of a correlation between the increase of cGMP function and cellular growth and malignancy.