Developments in understanding and applying prebiotics in research and practice-an ISAPP conference paper

AIMS

The concept of using specific dietary components to selectively modulate the gut microbiota to confer a health benefit, defined as prebiotics, originated in 1995. In 2018, a group of scientists met at the International Scientific Association for Probiotics and Prebiotics annual meeting in Singapore to discuss advances in the prebiotic field, focussing on issues affecting functionality, research methodology and geographical differences.

METHODS AND RESULTS

The discussion ranged from examining scientific literature supporting the efficacy of established prebiotics, to the prospects for establishing health benefits associated with novel compounds, isolated from different sources.

CONCLUSIONS

While many promising candidate prebiotics from across the globe have been highlighted in preliminary research, there are a limited number with both demonstrated mechanism of action and defined health benefits as required to meet the prebiotic definition. Prebiotics are part of a food industry with increasing market sales, yet there are great disparities in regulations in different countries. Identification and commercialization of new prebiotics with unique health benefits means that regulation must improve and remain up-to-date so as not to risk stifling research with potential health benefits for humans and other animals.

SIGNIFICANCE AND IMPACT OF STUDY

This summary of the workshop discussions indicates potential avenues for expanding the range of prebiotic substrates, delivery methods to enhance health benefits for the end consumer and guidance to better elucidate their activities in human studies.

Post marathon cardiac troponin T is associated with relative exercise intensity

OBJECTIVES

This study aimed to investigate whether measures of cardiopulmonary fitness and relative exercise intensity were associated with high sensitivity cardiac troponin T (cTnT) rise after a road marathon.

METHODS

Fifty-two marathon runners (age 39±11 years, body mass 76.2±12.9kg, height 1.74±0.09m) attended the laboratory between 2 and 3 weeks prior to attempting the Brighton Marathon, UK. Running economy at 10kmh^-1 (RE10) and race pace (RERP), ventilatory threshold (VT) and VO₂max tests were completed. CTnT was measured within 48h prior to the marathon and within 10min of completing the marathon, using a high sensitivity assay. Heart rates (HR) were recorded throughout the marathon.

RESULTS

Runners demonstrated a significant increase in cTnT over the marathon (pre-race 5.60±3.27ngL^-1, post-race 74.52±30.39ngL^-1, p<0.001). Markers of endurance performance such as running economy (10kmh^-1 223±18mlkg^-1km^-1; race pace 225±22mlkg^-1km^-1), VT (38.5±6.4mlkg^-1min^-1) and V˙O₂max (50.9±7.7mlkg^-1min^-1) were not associated with post-race cTnT. Runners exercise intensity correlated with post-race cTnT (mean HR %VT 104±5%, r=0.50; peak HR %VT 118±8%, r=0.68; peak HR %V˙O₂max 96±6, r=0.60, p<0.05) and was different between the low, medium and high cTnT groups (p<0.05).

CONCLUSIONS

CTnT increases above reference limits during a marathon. Magnitude of cTnT rise is related to exercise intensity relative to ventilatory threshold and V˙O₂max, but not individuals' absolute cardiopulmonary fitness, training state or running history.

Screening a protein kinase inhibitor library against Plasmodium falciparum

Background

Protein kinases have been shown to be key drug targets, especially in the area of oncology. It is of interest to explore the possibilities of protein kinases as a potential target class in Plasmodium spp., the causative agents of malaria. However, protein kinase biology in malaria is still being investigated. Therefore, rather than assaying against individual protein kinases, a library of 4731 compounds with protein kinase inhibitor-like scaffolds was screened against the causative parasite, Plasmodium falciparum. This approach is more holistic and considers the whole kinome, making it possible to identify compounds that inhibit more than one P. falciparum protein kinase, or indeed other malaria targets.

Results

As a result of this screen, 9 active compound series were identified; further validation was carried out on 4 of these series, with 3 being progressed into hits to lead chemistry. The detailed evaluation of one of these series is described.

Discussion

This screening approach proved to be an effective way to identify series for further optimisation against malaria. Compound optimisation was carried out in the absence of knowledge of the molecular target. Some of the series had to be halted for various reasons. Mode of action studies to find the molecular target may be useful when problems prevent further chemical optimisation.

Conclusions

Progressible series were identified through phenotypic screening of a relatively small focused kinase scaffold chemical library.

Electronic supplementary material

The online version of this article (10.1186/s12936-017-2085-4) contains supplementary material, which is available to authorized users.

Discovery of a Quinoline-4-carboxamide Derivative with a Novel Mechanism of Action, Multistage Antimalarial Activity, and Potent in Vivo Efficacy

The antiplasmodial activity, DMPK properties, and efficacy of a series of quinoline-4-carboxamides are described. This series was identified from a phenotypic screen against the blood stage of Plasmodium falciparum (3D7) and displayed moderate potency but with suboptimal physicochemical properties and poor microsomal stability. The screening hit (1, EC₅₀ = 120 nM) was optimized to lead molecules with low nanomolar in vitro potency. Improvement of the pharmacokinetic profile led to several compounds showing excellent oral efficacy in the P. berghei malaria mouse model with ED₉₀ values below 1 mg/kg when dosed orally for 4 days. The favorable potency, selectivity, DMPK properties, and efficacy coupled with a novel mechanism of action, inhibition of translation elongation factor 2 (PfEF2), led to progression of 2 (DDD107498) to preclinical development.

Trisubstituted Pyrimidines as Efficacious and Fast-Acting Antimalarials

In this paper we describe the optimization of a phenotypic hit against Plasmodium falciparum, based on a trisubstituted pyrimidine scaffold. This led to compounds with good pharmacokinetics and oral activity in a P. berghei mouse model of malaria. The most promising compound (13) showed a reduction in parasitemia of 96% when dosed at 30 mg/kg orally once a day for 4 days in the P. berghei mouse model of malaria. It also demonstrated a rapid rate of clearance of the erythrocytic stage of P. falciparum in the SCID mouse model with an ED₉₀ of 11.7 mg/kg when dosed orally. Unfortunately, the compound is a potent inhibitor of cytochrome P450 enzymes, probably due to a 4-pyridyl substituent. Nevertheless, this is a lead molecule with a potentially useful antimalarial profile, which could either be further optimized or be used for target hunting.

Discovery of Inhibitors of Trypanosoma brucei by Phenotypic Screening of a Focused Protein Kinase Library

A screen of a focused kinase inhibitor library against Trypanosoma brucei rhodesiense led to the identification of seven series, totaling 121 compounds, which showed >50 % inhibition at 5 μm. Screening of these hits in a T. b. brucei proliferation assay highlighted three compounds with a 1H-imidazo[4,5-b]pyrazin-2(3H)-one scaffold that showed sub-micromolar activity and excellent selectivity against the MRC5 cell line. Subsequent rounds of optimisation led to the identification of compounds that exhibited good in vitro drug metabolism and pharmacokinetics (DMPK) properties, although in general this series suffered from poor solubility. A scaffold-hopping exercise led to the identification of a 1H-pyrazolo[3,4-b]pyridine scaffold, which retained potency. A number of examples were assessed in a T. b. brucei growth assay, which could differentiate static and cidal action. Compounds from the 1H-imidazo[4,5-b]pyrazin-2(3H)-one series were found to be either static or growth-slowing and not cidal. Compounds with the 1H-pyrazolo[3,4-b]pyridine scaffold were found to be cidal and showed an unusual biphasic nature in this assay, suggesting they act by at least two mechanisms.

The design and synthesis of potent and selective inhibitors of Trypanosoma brucei glycogen synthase kinase 3 for the treatment of human african trypanosomiasis

Glycogen synthase kinase 3 (GSK3) is a genetically validated drug target for human African trypanosomiasis (HAT), also called African sleeping sickness. We report the synthesis and biological evaluation of aminopyrazole derivatives as Trypanosoma brucei GSK3 short inhibitors. Low nanomolar inhibitors, which had high selectivity over the off-target human CDK2 and good selectivity over human GSK3β enzyme, have been prepared. These potent kinase inhibitors demonstrated low micromolar levels of inhibition of the Trypanosoma brucei brucei parasite grown in culture.

From on-target to off-target activity: identification and optimisation of Trypanosoma brucei GSK3 inhibitors and their characterisation as anti-Trypanosoma brucei drug discovery lead molecules

Human African trypanosomiasis (HAT) is a life-threatening disease with approximately 30 000–40 000 new cases each year. Trypanosoma brucei protein kinase GSK3 short (TbGSK3) is required for parasite growth and survival. Herein we report a screen of a focused kinase library against T. brucei GSK3. From this we identified a series of several highly ligand-efficient TbGSK3 inhibitors. Following the hit validation process, we optimised a series of diaminothiazoles, identifying low-nanomolar inhibitors of TbGSK3 that are potent in vitro inhibitors of T. brucei proliferation. We show that the TbGSK3 pharmacophore overlaps with that of one or more additional molecular targets.

Chemical proteomic analysis reveals the drugability of the kinome of Trypanosoma brucei

The protozoan parasite Trypanosoma brucei is the causative agent of African sleeping sickness, and there is an urgent unmet need for improved treatments. Parasite protein kinases are attractive drug targets, provided that the host and parasite kinomes are sufficiently divergent to allow specific inhibition to be achieved. Current drug discovery efforts are hampered by the fact that comprehensive assay panels for parasite targets have not yet been developed. Here, we employ a kinase-focused chemoproteomics strategy that enables the simultaneous profiling of kinase inhibitor potencies against more than 50 endogenously expressed T. brucei kinases in parasite cell extracts. The data reveal that T. brucei kinases are sensitive to typical kinase inhibitors with nanomolar potency and demonstrate the potential for the development of species-specific inhibitors.

Aspects of neural plasticity in the central nervous system-III. Methodological studies on the microdialysis technique

Some methodological aspects of the intracerebral microdialysis technique have been investigated: the existence of a pressure gradient at the level of the dialyzing membrane, the substance diffusion from the microdialysis probe and the extent of tissue damage induced by the implantation of the microdialysis probe. At the level of the dialyzing membrane a rough balance between the pressure inside the probe and the one present in the extracellular fluid compartment has been observed. The pattern of substance diffusion in the tissue showed a large variability depending on the substance used and the experimental conditions. Relevant deductions can be made by the use of labeled markers. By means of this approach, the diffusion pattern of tritiated ganglioside GM1 in the tissue around the probe could be shown to follow a biexponential pattern, suggesting a two-step process of diffusion. The degree of tissue damage induced by the microdialysis probe was assessed by analyzing the glial reaction, and was measured by means of semiquantitative immunocytochemistry of glial fibrillary acidic protein immunoreactivity. Only a limited area of neuronal damage was observed in the region surrounding the microdialysis probe. The amount of glial reaction after probe implantation was shown to be comparable with that induced by the implantation of a microinjection cannula.

IspE inhibitors identified by a combination of in silico and in vitro high-throughput screening

CDP-ME kinase (IspE) contributes to the non-mevalonate or deoxy-xylulose phosphate (DOXP) pathway for isoprenoid precursor biosynthesis found in many species of bacteria and apicomplexan parasites. IspE has been shown to be essential by genetic methods and since it is absent from humans it constitutes a promising target for antimicrobial drug development. Using in silico screening directed against the substrate binding site and in vitro high-throughput screening directed against both, the substrate and co-factor binding sites, non-substrate-like IspE inhibitors have been discovered and structure-activity relationships were derived. The best inhibitors in each series have high ligand efficiencies and favourable physico-chemical properties rendering them promising starting points for drug discovery. Putative binding modes of the ligands were suggested which are consistent with established structure-activity relationships. The applied screening methods were complementary in discovering hit compounds, and a comparison of both approaches highlights their strengths and weaknesses. It is noteworthy that compounds identified by virtual screening methods provided the controls for the biochemical screens.

Nuclear DBF-2-related kinases are essential regulators of cytokinesis in bloodstream stage Trypanosoma brucei

Nuclear DBF-2-related (NDR) kinases are essential regulators of cell cycle progression, growth, and development in many organisms and are activated by the binding of an Mps One Binder (MOB) protein partner, autophosphorylation, and phosphorylation by an upstream STE20 family kinase. In the protozoan parasite, Trypanosoma brucei, the causative agent of human African trypanosomiasis, the NDR kinase, PK50, is expressed in proliferative life cycle stages and was shown to complement a yeast NDR kinase mutant cell line. However, the function of PK50 and a second NDR kinase, PK53, in T. brucei has not been determined to date, although trypanosome MOB1 is known to be essential for cytokinesis, suggesting the NDR kinases may also be involved in this process. Here, we show that specific depletion of PK50 or PK53 from bloodstream stage trypanosomes resulted in the rapid accumulation of cells with two nuclei and two kinetoplasts, indicating that cytokinesis was specifically inhibited. This led to a deregulation of the cell cycle and cell death and provides genetic validation of these kinases as potential novel drug targets for human African trypanosomiasis. Recombinant active PK50 and PK53 were produced and biochemically characterized. Both enzymes autophosphorylated, were able to trans-phosphorylate generic kinase substrates in vitro, and were active in the absence of phosphorylation by an upstream kinase. Additionally, both enzymes were active in the absence of MOB1 binding, which was also demonstrated to likely be a feature of the kinases in vivo. Biochemical characterization of recombinant PK50 and PK53 has revealed key kinetic differences between them, and the identification of in vitro peptide substrates in this study paves the way for high throughput inhibitor screening of these kinases.

First administration to humans of a monoclonal antibody cocktail against rabies virus: safety, tolerability, and neutralizing activity

Immediate passive immune prophylaxis as part of rabies post-exposure prophylaxis (PEP) often cannot be provided due to limited availability of human or equine rabies immunoglobulin (HRIG and ERIG, respectively). We report first clinical data from two phase I studies evaluating a monoclonal antibody cocktail CL184 against rabies. The studies included healthy adult subjects in the USA and India and involved two parts. First, subjects received a single intramuscular dose of CL184 or placebo in a double blind, randomized, dose-escalation trial. Second, open-label CL184 (20IU/kg) was co-administered with rabies vaccine. Safety was the primary objective and rabies virus neutralizing activity (RVNA) was investigated as efficacy parameter. Pain at the CL184 injection site was reported by less than 40% of subjects; no fever or local induration, redness or swelling was observed. RVNA was detectable from day 1 to day 21 after a single dose of CL184 20 or 40IU/kg. All subjects had adequate (>0.5IU/mL) RVNA levels from day 14 onwards when combined with rabies vaccine. CL184 appears promising as an alternative to RIG in PEP.

[Importance of physical activity for prevention of chronic diseases]

A lot of epidemiological studies have shown that physical activity can prevent the development of chronic diseases such as obesity, diabetes, osteoporosis, cardiovascular diseases and cancer Physical activity can be classified by rate of energy expenditure: light intensity 1-3 METs, moderate 3-6 MET's, vigorous 6-9 MET's, very vigorous >9 MET's. Although it is evident that an active lifestyle has many health benefits and sedentary habits are associated with an increased risk of chronic diseases, the debate still continues as to how much, what type, how often, at what intensity physical activity should be performed to have a positive effect on the health. Reduction of cardiovascular risk is observed already with a moderate intensity physical activity (3-6METs); whilst to improve physical fitness training must be more vigorous (6-9 METs). In conclusion good goals are achieved when moderate levels of physical activity are performed on a regular basis (at least 3- 5 days a week for 30 minutes). But to reach also countable results on body weight control the frequency should be 5-7 days a week for 60 minutes.

Telecardiogram: still of matter in the modern cardiac imaging era?

The modern cardiovascular imaging era has seen the introduction in clinical practice of highly innovative and performing diagnostic features. The negative side of this outstanding evolution risks to be an under-assessment of well-established classical diagnostic techniques. Thereby, to support the actual relevance of a properly executed chest X-ray, this article describes two paradigmatic cases of exceptional cardiac abnormalities, in which X-rays played a key diagnostic role.

[Pendrin: physiology, molecular biology and clinical importance]

Pendrin, first identified in 1997, belongs to a superfamily of anion transporters localized in the thyroid gland, inner ear and kidney. Immunohistochemical studies have shown that pendrin is expressed at the apical surface of follicular thyroid cells, where it acts as a Cl-/I- exchanger regulating the chloride transport from the cytoplasm to the colloid space. In the inner ear, pendrin has been found in the stria vascularis of the cochlea and in the endolymphatic duct and sac, where it functions as a Cl- /HCO-3 exchanger. Finally, pendrin is expressed in the kidney, where it is localized in the apical membrane of type-B intercalated cells and non-A, non-B intercalated cells of the cortical collecting ducts and connecting tubules, where it again acts as a Cl /HCO-3 exchanger regulating the acid-base status and chloride homeostasis. Pendrin is encoded by the PDS gene, which is mapped on chromosome 7 (7q22-31.1). Mutations of PDS lead to the Pendred syndrome, a genetic disorder transmitted as an autosomal recessive trait characterized by sensorineural deafness and goiter. It is reasonable to hypothesize that patients affected by Pendred's syndrome may have disturbances of renal function, especially in the regulation of electrolytes and acid-base balance in stress conditions.

Coronary stenting and abciximab in primary angioplasty for ST-segment-elevation myocardial infarction

Advances in anti-platelet therapy and improvement of stent deployment techniques have improved the safety and efficacy of stenting in the setting of ST-segment-elevation myocardial infarction (STEMI). However, in randomized trials, routine coronary stenting does not reduce mortality and re-infarction, compared to balloon angioplasty. Further, the benefits in target vessel revascularization seem to be reduced when applied to unselected patients with STEMI. Direct stenting represents an attractive strategy with potential benefits in terms of myocardial perfusion. Future large randomized trials are needed to evaluate whether this strategy has a significant impact on outcome, and to provide a cost-benefit analysis of the unrestricted use of drug-eluting stents in this high-risk subset of patients. The additional use of abciximab reduces mortality in primary angioplasty. Since the feasibility of long-distance transportation has been shown in several randomized trials, early pharmacological pre-treatment may confer further advantages by early recanalization and shorter ischaemic time, particularly in high-risk patients. Further randomized trials are needed to clarify the potential benefits from early abciximab administration and the potential role of small molecules in primary angioplasty for STEMI.

[Transient erythroblastopenia in children: assessment of a hospital caseload]

Transient erythroblastopenia of childhood (TEC) is an acquired, self-limiting, uncommon disease, characterized by the temporary arrest of red cell production, resulting in moderate to several anemia. We retrospectively evaluated four cases of TEC, identified during an 8-year period of time in our Department of Pediatrics, including one patient, who developed TEC during the course of Kawasaki's syndrome. Clinical and hematological presentations of patients were analyzed and the most recent data of literature were reviewed. In conclusion, we suggest that a better knowledge of this rare and unique hematologic disorder of childhood may help make a correct diagnosis, avoiding unnecessary laboratory tests (e.g. bone marrow aspirate) and inappropriate therapeutic modalities.

Emergency medical services in mass gatherings: the experience of the Formula 1 Grand Prix 'San Marino' in Imola

Mass gatherings are special situations for which mass medical care must be preplanned. Acute emergencies occur at public gatherings and medical coverage on site has proven benefit. Responsibility of general plan, management of specific problems, transport planning, communications system, guidelines and protocols, special situations management, ancillary supports, sources of extra help for unforeseen needs are the most important items to consider. In mass gatherings the whole emergency medical service (EMS) planning and management has to depend on the emergency department direction, with its authority on all aspects of patient care in the EMS system. This report concerns the planning of EMS and of medical care in a situation at risk for mass casualties at the Formula I Grand Prix-Championship Racing 'San Marino' of Imola.

Multicenter study of Abbott AxSYM Digoxin II assay and comparison with 6 methods for susceptibility to digoxin-like immunoreactive factors

Performance characteristics of the Abbott nonpretreatment AxSYM Digoxin II assay were evaluated for quantification of digoxin at four independent sites. Correlation of digoxin measurements with the Abbott pretreatment AxSYM, Baxter Stratus II, Abbott TDx/ TDxFLx II, Abbott IMx, Emit 2000, and Beckman Synchron CX digoxin assays showed acceptable agreement, as indicated by: slope values > 0.84, r > 0.90, y-intercepts for all comparisons at or below the assay detection limit, and Sy/x ranging between 7.5% and 15.4% of the average digoxin value. Susceptibility to interference from digoxin-like immunoreactive factors (DLIFs) was examined in 233 samples from renal patients, liver disease patients, cord blood, and third-trimester pregnancies; the AxSYM Digoxin II assay demonstrated the least DLIFs interference. DLIF susceptibility for four of the methods was significantly greater (P < 0.05) than in the AxSYM Digoxin II assay; susceptibilities of the Stratus II and Emit 2000 methods were similar to the AxSYM Digoxin II assay.

Short- and long-term changes in striatal neurons and astroglia after transient forebrain ischemia in rats

BACKGROUND AND PURPOSE

The striatum is one of the regions most sensitive to transient forebrain ischemia. After 30-minute ischemia, areas of massive neuronal degeneration are clearly detectable a few hours after the insult and attain their maximal extension 24 hours after the insult. However, for most cellular and neurochemical parameters it is not known whether some recovery occurs at later times. We examined certain cell populations in the caudate putamen at different times after transient ischemia.

METHODS

Adult male Sprague-Dawley rats were subjected to 30-minute forebrain ischemia (four-vessel occlusion model). Six experimental groups were considered: control animals and ischemic animals killed 4 hours, 1 day, 7 days, 40 days, and 8 months after reperfusion. Three striatal cell populations were examined by means of immunocytochemistry coupled to computer-assisted image analysis: vulnerable medium spiny neurons, resistant aspiny neurons, and reactive astrocytes, labeled for their content of dopamine- and cAMP-regulated phosphoprotein mr32 (DARPP-32), somatostatin and neuropeptide Y, and glial fibrillary acidic protein, respectively.

RESULTS

(1) The area containing DARPP-32 immunoreactive neurons was markedly decreased (15% to 20% of control caudate putamen area) at 1 day after reperfusion and partially recovered at the following times (40% to 50% at 7 days and 50% to 60% at 40 days and 8 months after reperfusion). (2) The appearance of reactive astrocytes was precocious (4 hours to 1 day after ischemia) in the medial caudate putamen, the region in which DARPP-32 recovered within 40 days after ischemia, and late (7 to 40 days after ischemia) in the lateral caudate putamen, where no DARPP-32 recovery was detected. (3) Neuropeptide Y/somatostatin-containing neurons resisted the ischemic insult and could be detected in areas devoid of DARPP-32 immunoreactive neurons as long as 8 months after reperfusion.

CONCLUSIONS

The present results show a marked recovery of DARPP-32-positive neurons within 40 days after 30-minute forebrain ischemia in the medial, but not the lateral, caudate putamen. Medial caudate putamen also contains a high density of reactive astrocytes on the first day after ischemia, suggesting that astrocytic support has an important role in the spontaneous recovery of ischemic neurons.

Cabergoline in the treatment of early Parkinson's disease: results of the first year of treatment in a double-blind comparison of cabergoline and levodopa. The PKDS009 Collaborative Study Group

Cabergoline is a potent D2 receptor agonist with a half-life of 65 hours that may provide continuous dopaminergic stimulation administered once daily. In this study, we randomized de novo Parkinson's disease (PD) patients to treatment with increasing doses of cabergoline (0.25 to 4 mg/d) or levodopa (100 to 600 mg/d) up to the optimal or maximum tolerated dose. Decreases of > 30% in motor disability (Unified Parkinson's Disease Rating Scale Factor III) versus baseline were considered indicative of clinical improvement. If 30% improvement was not achieved, levodopa/ carbidopa could be added on an open basis. Of the 208 patients entered in the cabergoline group, 175 remained in the study for 1 year at a mean dose of 2.8 mg/d; in the levodopa group, 176 of the 205 patients entered were still on study after 1 year at a mean dose of 468 mg/d. The proportion of patients requiring additional levodopa/carbidopa increased in the cabergoline group from 18% at 6 months to 38% at 1 year versus 10% (p = 0.05) at 6 months and 18% (p < 0.01) at 1 year in the levodopa group. The proportion of patients showing clinical improvement did not differ significantly between the two groups, or between the subgroups on monotherapy, at any endpoint. Irrespective of levodopa/carbidopa addition, 81% of patients in the cabergoline group and 87% of patients in the levodopa group were clinically improved at 1 year (p = 0.189); the corresponding figures for the subgroup on monotherapy were 79% in the cabergoline-treated patients and 86% in the levodopa-treated patients (p = 0.199). The mean difference versus baseline in Unified Parkinson's Disease Rating Scale Factor III scores in patients who remained on monotherapy up to 1 year was 12.6 (95% confidence interval [CI]: 10.8, 14.3) in the cabergoline group and 16.4 (95% CI: 14.8, 18.0) in the levodopa group. Adverse events occurred in 76% of patients on cabergoline and in 66% of patients on levodopa. The severity profile for reported events was similar for the two agents. The results of this study indicate that cabergoline treatment for up to 1 year is only marginally less effective than levodopa in the proportion of patients who can be treated in monotherapy. More than 60% of de novo PD patients could be managed on cabergoline alone up to 1 year. In the patients in whom levodopa/carbidopa was needed, the combination therapy provided efficacy similar to that obtained with levodopa alone, with a relevant sparing of levodopa.

Cryoprostatectomy consistently elevates serum creatine kinase-MB isoenzyme

STUDY OBJECTIVE

To measure serum CK-MB, a market of myocardial infarction (MI), in elderly men before and after cryoprostatectomy.

DESIGN

Serum CK-MB was measured on each patient before and after cryoprostatectomy. Each patient's preoperative result was used as control measurement for comparison with measurements made after cryoprostatectomy.

SETTING

Inpatient operating room and postanesthetic recovery unit of a university-affiliated general hospital.

PATIENTS

38 male patients, mean (SEM) age 69.1 +/- 1.4 years, undergoing cryoprostatectomy.

INTERVENTIONS

All patients had a 12-lead ECG prior to surgery, in the recovery room, and 24 hours after surgery. Serum CK-MB was measured prior to induction of anesthesia, on arrival in the recovery room, and at 8 and 24 hours after surgery. Lactate dehydrogenase (LDH) and isoenzymes also were measured in 10 patients before and after cryoprostatectomy.

MEASUREMENTS AND MAIN RESULTS

All patients underwent uneventful cryoprostatectomy. No patients had new ECG changes after surgery. All patients had normal serum CK and CK-MB concentrations before surgery. Serum CK and CK-MB were significantly elevated after cryoprostatectomy (p < 0.001). Enzyme values were greatest 8 hours after surgery: total CK mean 1453 +/- 145 U/L (range 199 to 3,356 U/L); CK-MB mean 52 +/- 3 ng/ml (range 12 to 114 ng/ml) or 5.0 +/- 0.5% of total CK (range 1.6% to 12.4%). All patients had significant elevations of LDH after cryoprostatectomy but did not show an increase in the ratio of LDH1 to LDH2 isoenzymes. Finally, unlike patients with an acute MI, the activity of CK-MB isoenzyme when measured by gel electrophoresis was two to three times greater (mean, 2.6 +/- 0.7) than the concentration measured with the monoclonal antibody assay in patients after cryoprostatectomy.

CONCLUSION

Serum CK-MB is an unreliable test to diagnose an MI in patients who have undergone cryoprostatectomy.

Acute effects of TTFCA on capillary filtration in severe venous hypertension

The acute variation in capillary filtration [CF] was evaluated with strain-gauge plethysmography in patients with severe venous hypertension due to deep venous disease. Two groups were selected and randomly treated with a single oral dose or TTFCA (60 mg or 120 mg). CF was assessed again after 5 and 10 hours. Eleven patients were randomised in the 60 mg group and 9 in the 120 mg group. Also 5 normal subjects were studied with the same procedure to act as controls. No variations in CF were observed in normal limbs. In both groups of patients there was a significant decrease in CF after 5 and 10 hours. The percent decrease in CF after 10 hours was higher in the high dose group. These results indicate that TTFCA is acutely effective in reducing CF and oedema in subjects with venous hypertensive microangiopathy. The effects of TTFCA on CF appear to be dose related.

[The microcirculatory activity of Centella asiatica in venous insufficiency. A double-blind study]

In 87 patients with chronic venous hypertensive microangiopathy the efficacy of oral FTTCA (Centella asiatica) administered for 60 days was tested. The microcirculatory effects of two dosages (30 mg bid and 60 mg bid) versus placebo was assessed in a double blind study. The compound was well tolerated and no unwanted effects were observed. Microcirculatory parameters--peri-malleolar skin flux at rest (RF) and transcutaneous PO2 and PCO2--improved as did the abnormally increased RF, PCO2 decreased and PO2 increased in comparison with values measured at inclusion. These results confirm the efficacy of FTTCA in venous hypertensive microangiopathy. Furthermore the effects of FTTCA appear to be dose-related.

Involvement of alpha 2-receptors in the analgesia induced by transient forebrain ischemia in rats

Transient forebrain ischemia induced in rats by the four-vessel occlusion method produced analgesic effects in the hotplate test that persisted for 2 weeks. Ischemia-induced analgesia was attenuated by low doses of alpha 2-agonist clonidine (0.01-0.10 mg/kg, IP) and enhanced by low doses of alpha 2-antagonists yohimbine (1-2 mg/kg, IP) and idazoxan (0.25-1.00 mg/kg, IP) administration 7 days after ischemia. Ischemia-induced analgesia was not affected by methysergide, naloxone, propranolol, or phenoxybenzamine administered 7 days after ischemia, when motor control and arousal level of rats recovered to normal conditions. The enhanced response to yohimbine was antagonized by pretreatment with clonidine (0.75 mg/kg, IP) and naloxone (10 mg/kg, IP), suggesting the involvement of endogenous opioid peptides. The enhanced response to yohimbine was still present 2 months after ischemia, when preischemic hotplate threshold was restored. As alpha 2-agonists reduce and alpha 2-antagonists increase the outflow of central noradrenaline, it is suggested that activation of central noradrenergic systems is involved in the mediation of ischemia-induced analgesia.

Effects of polyamine synthesis blockade on neuronal loss and astroglial reaction after transient forebrain ischemia

Polyamines and ornithine decarboxylase, the polyamine biosynthetic enzyme, have been demonstrated to increase in the early phase of several types of brain lesion. However, their role in the pathogenesis of tissue damage is still debated. In the present paper the effects of treatments with alpha-difluoromethylornithine, a suicide inhibitor of ornithine decarboxylase, have been investigated in a model of transient forebrain ischemia. Three treatment schedules were used: alpha-difluoromethylornithine treatment was either started 3 hr before and repeated 1 hr after the insult, or started at the time of the insult and continued for 3 or 7 days after post-ischemic reperfusion. The rats were sacrificed 4 hr, 7 or 40 days after reperfusion, respectively. The acute experiment demonstrated that alpha-difluoromethylornithine can reduce the increase of glial fibrillary acid protein immunoreactivity, an early marker of astroglial reaction, in ischemic striatum. Subchronic and chronic alpha-difluoromethylornithine treatments induced a worsening of the morphological outcome of the ischemic lesion. In caudate-putamen a trend for an increase of the area of neuronal loss was present after both treatments. In the hippocampal formation, a significant increase in the severity of neuronal lesion was observed in the mildly lesioned CA3 field. In addition, other alterations of lesioned tissue were observed in alpha-difluoromethylornithine-treated animals, including increases of non-neuronal cells at 7 and especially 40 days post-lesion in striatum and CA3 hippocampal field. In conclusion, present data indicate that ornithine decarboxylase activation after ischemic lesion is a crucial factor for survival of mildly lesioned neurons and proper tissue reaction to the ischemic lesion. The experiment on acute alpha-difluoromethylornithine treatment suggests that these effects may be, at least in part, related to putrescine-induced activation of astroglial cells in the early post-lesion period.

Detection of free radicals during brain ischemia and reperfusion by spin trapping and microdialysis

Extracellular free radicals were detected in rat striatal perfusate samples by intracerebral microdialysis coupled to the spin trapping technique. Five Sprague-Dawley rats were subjected to 30 min of global ischemia followed by reperfusion; throughout the experimental period the intrastriatal dialysing probe was perfused with Ringer's solution containing the spin trap agent pyridyl-N-oxide-t-butylnitrone (100 mM) together with the iron chelating agent diethylentriaminepentacetic acid (100 microM). A radical adduct occurred during ischemia and early reperfusion, but not in basal conditions; the spin adduct was characterized as a carbon centered radical, consistent with the presence of an oxidative attack on membrane lipids. The direct evidence of the formation of free radicals supports the hypothesis that free radicals play a role in the pathogenesis of the histological damage during brain ischemia.

Siagoside selectively attenuates morphological and functional striatal impairments induced by transient forebrain ischemia in rats

BACKGROUND AND PURPOSE

Transient forebrain ischemia induced in rats by the four-vessel occlusion method is known to produce severe neural damage in the hippocampus and striatum and a behavioral syndrome the major symptom of which is a working memory deficit. Recent evidence suggests that monosialogangliosides can ameliorate postischemic symptoms. Our purpose was to study the effect of siagoside, the inner ester of GM1 ganglioside, on some behavioral and morphological impairments induced by four-vessel occlusion in rats.

METHODS

Rats were injected daily with 5 mg/kg i.p. siagoside starting 4 hours after the cerebral ischemia. After 14 days the rats were tested for working memory in a water T maze or scored for apomorphine-induced stereotypy. The rats were killed 21 days after the cerebral ischemia. Histological and computer-assisted morphometric analyses were performed on cresyl violet-stained brain sections, which were graded according to a neuropathologic score, and on sections stained with a monoclonal antiserum against dopamine and cyclic adenosine-3',5'-monophosphate-regulated phosphoprotein, a marker for striatal dopaminoceptive neurons.

RESULTS

Siagoside treatment reduced the stereotypy score induced by low doses of apomorphine and the extent of striatal lesions but did not affect the working memory deficit or the extent of hippocampal lesions.

CONCLUSION

Daily siagoside treatment after acute cerebral ischemia attenuates some morphological and functional deficits related to striatal damage. These effects can be interpreted as a selective protective action on striatal neural populations or as a modulatory action on neural systems involved in striatal control. These data are consistent with preliminary clinical reports showing that monosialogangliosides enhance motor recovery after acute ischemic stroke.

[Efficacy of TTFCA in reducing the ratio between lymphatic and plasma protein concentration in lymphatic and postphlebitic edema]

In subjects with lymphatic problems and postphlebitic edema there is a significant difference in the ratio between lymphatic and plasma concentration of protein (CL/CP) in the foot. Two groups of patients were studied (one group with lymphedema and the other with postphlebitic limbs) in order to assess the CL/CP ratio before and after TTCFA treatment (Centellase). The study confirmed the efficacy of treatment in achieving a significant reduction of CL/CP and distal edema.

The endurance triathlon: metabolic changes after each event and during recovery

We analyzed metabolic parameters in 11 volunteers after each segment of an endurance triathlon and, in a separate year, analyzed similar parameters in eight volunteers during 6 d of recovery following completion of an endurance triathlon. After the 2.4-mile ocean swim, serum lactate tripled, and albumin and muscle enzymes were increased. After the 112-mile bicycle ride, mild dehydration occurred, and muscle enzymes and uric acid levels increased markedly. Serum lactate was elevated over baseline but was lower then after the swim. After the 26.2-mile run, dehydration and muscle damage progressed; serum triglycerides dropped by 50%. Serum lactate remained elevated, but less than after either of the other segments. During recovery, muscle enzymes continued to rise and peaked (creatine phosphokinase on the day following the triathlon at 4920 +/- 685 U.ml-1; range 1321-16,746); creatine phosphokinase and lactate dehydrogenase remained significantly elevated at the end of the recovery period. Total protein and albumin decreased, suggesting alterations in their synthesis or their utilization for tissue repair. Serum cholesterol levels fell significantly until the 4th d. Serum triglycerides slowly increased to baseline over 4 d, suggesting their use as energy substrate during recovery. Thus, competition in an endurance triathlon causes skeletal muscle injury that appears early, increases as the triathlon progresses, and is still apparent even 6 d after completion of the triathlon. Changes in plasma proteins and lipid suggest that energy substrate utilization is shifted as the triathlon progresses and as the body repairs itself following completion of the event.

Decrease in mRNA levels but not in the density of D2 dopamine receptors in rat striatum after transient forebrain ischemia

D2 dopamine receptor mRNA was analyzed by in situ hybridization histochemistry in rat striatum 7 days after transient forebrain ischemia. A patchy disappearance of the D2 receptor mRNA was observed in the dorsolateral striatum. In the same area, a disappearance of D1 binding sites occurred in the absence of significant changes in D2 receptor density. These results suggest that, although D2 receptors seem to be apparently unaffected after forebrain ischemia, a long-lasting impairment of their neosynthesis may be present in striatal D2 dopaminoceptive neurons.

Changes in striatal mu and delta opioid receptors after transient forebrain ischemia: a quantitative autoradiographic study

Transient forebrain ischemia induces specific changes in several neurochemical markers in the dorsolateral striatum. In the present paper, the density and distribution of mu and delta opioid receptors were analyzed in rat striatum 7 days after 30 min forebrain ischemia using the 4-vessel occlusion model. A marked (about 70%) decrease in the density of both opioid receptor subtypes was found in the dorsolateral striatum overlapping the areas of histological damage and of D1 dopamine receptor disappearance. Moreover, the density of delta opioid receptors and of the diffuse mu opioid receptors was also affected (30% decrease) in the ventromedial striatum, an area which is substantially spared by the ischemic lesion. In contrast, the striatal patches of mu opioid receptors were not affected in the ventro-medial striatum and were preserved to a large extent in the area of lesion, although their area and receptor density resulted markedly reduced. The impairment of both opioid receptor subtypes suggests that opiate systems, like dopaminergic systems, are involved in the neurochemical changes observed in the striatum after transient forebrain ischemia.

Microdialysis and luminescent probe: analytical and clinical aspects

Immobilized enzymes are widely used in the clinical laboratory to assay several analytes and enzymes. The use of immobilized enzymes makes these reagents recoverable, disposable and in most cases increases their stability and catalytic activity. In conjunction with bioluminescent enzymes (firefly and bacterial luciferases) and chemiluminescent catalyst (peroxidase) we set up high-sensitive flow sensors based on the use of nylon tube coil or epoxy methacrylate column as solid support. For in-vivo determination a suitable microdialysis probe inserted directly into brain or blood allows continuous measurement of extracellular lactate levels by means of a bioluminescent flow detector system. This procedure performs more measurements in the same time interval than other systems (HPLC), e.g. to give a detailed description of the effects of ischemia, or other pathological events, on lactate concentration in the brain.

Evidence for a role of neosynthetized putrescine in the increase of glial fibrillary acidic protein immunoreactivity induced by a mechanical lesion in the rat brain

The effect of alpha-difluoromethylornithine (alpha-DFMO), an irreversible inhibitor of ornithine decarboxylase (ODC) the rate limiting enzyme of polyamine biosynthesis, was studied on the astroglial reaction in a model of mechanical brain injury. alpha-DFMO markedly decreased the astroglial activation induced by the microdialysis probe implantation in the striatum of the male rat, as studied by glial fibrillary acidic protein (GFAP) immunocytochemistry. This response was restored by putrescine (20 nmol/ml) administered via the microdialysis probe. These results suggest that the astroglial reaction and the polyamine biosynthesis activation induced by a localized mechanical lesion are causally linked phenomena.

Improvement of capillary permeability in patients with venous hypertension after treatment with TTFCA

The VSC (vacuum suction chamber) device, a new system to evaluate local capillary permeability, was used with laser Doppler flowmetry to study variations of permeability and of the microcirculation in 10 normal subjects; in 22 patients with moderate, superficial venous hypertension; and in 12 patients with postphlebitic limbs and severe venous hypertension. All these patients had distal (ankle and foot edema) in the evening. After a first assessment these subjects were studied again after two weeks without treatment and after two weeks' treatment with total triterpenic fraction of centella asiatica (TTFCA), tablets, 60 mg, tid. The VSC produces a wheal on the skin of the perimalleolar region that disappears (in average) in less than sixty minutes in normal subjects. The disappearance time (DT) is greater in conditions of increased capillary filtration and permeability. The three groups of subjects (normal and those with superficial and severe venous hypertension) had significantly different, increasing disappearance time of the wheals at the first observation. There were no significant changes after two weeks' observation, but after 2 weeks' treatment with TTFCA, there was a significant decrease of DT both in limbs with superficial and with deep venous incompetence. The improvement (decrease) of the abnormally increased capillary permeability was associated with a significant improvement of the microcirculation and symptoms (studied by an analogue scale line). In conclusion this study showed a combined improvement of the microcirculation and capillary permeability after treatment with TTFCA and the possibility of using the VSC to evaluate the effects of drugs (or other treatment) on local capillary permeability in patients with venous hypertension.

Cellular and synaptic alterations in the aging brain

The morphological and functional impairments observed in the aging brain are discussed in the framework of theoretical concepts, such as the existence of different modalities of intercellular communication and of specific trophic features in the central nervous system. The relevance of changes at the cellular level (disappearance of neuronal cell bodies and proliferation of astroglial cells) and at the synaptic level (alterations in neurotransmitter and receptor levels) is discussed. Two, non-mutually exclusive hypotheses are advanced to explain the frequent absence of correlation between neuropathological findings and functional deficits in aged patients. According to the first, the physiological reshaping of brain circuits during aging may lead to "wrong" readjustments of neural networks (e.g. due to less effective endogenous and exogenous orienting signals) causing minor morphological alterations but marked functional deficits. The second hypothesis maintains that the absence of correlation between neuropathological and functional deficits is due to the impairment of restricted neuronal populations ("pacemaker and command neurons") which play a special role in the hierarchical organization of neuronal networks. These neurons (inter alia, peptidergic neurons) may also be involved in volume transmission (diffusion of electrical and chemical signals in the extracellular fluid to reach distant targets). Moreover, the relevance of glial cells, not only as regulators of the extracellular medium but also on the basis of their trophic links with neurons, is considered. Finally, the interplay between trophic factors and therapeutical experience for the maintenance and/or recovery of an impaired function in elderly patients is discussed.

On the role of neuropeptide Y in information handling in the central nervous system in normal and physiopathological states. Focus on volume transmission and neuropeptide Y/alpha 2 receptor interactions

The NPY neurons play an important role in information handling in the CNS by their ability to interact in both wiring and volume transmission at the network, local circuit and synaptic level. The importance of NPY/alpha 2 receptor-receptor interactions in cardiovascular, neuroendocrine and vigilance control is emphasized. Alterations in these receptor-receptor interactions take place in the spontaneously hypertensive rats as well as in the ischemic brain, which may have profound consequences for the information handling and contribute to the functional alterations found in these pathophysiological states. Finally, in the aging brain there appears to exist a marked reduction in NPY transmission line, which may affect higher brain functions, such as learning and memory retrieval. The most impressive result is, however, the indications of a role for NPY in volume transmission, where NPY appears to produce syndromic actions via its conversion into biologically active fragments, which may have preferential actions at Y2 NPY receptors. These syndromic pathways may be altered in the spontaneously hypertensive rat and may be controlled by gonadal steroids and glucocorticoids. Glucocorticoid receptors have been demonstrated in all arcuate NPY neurons and all NA/NPY and A/NPY costoring neurons.

Capillary filtration and ankle edema in patients with venous hypertension treated with TTFCA

The variation of capillary filtration rate (CFR), ankle circumference (AC), and ankle edema (AE) was evaluated in three groups of patients with venous hypertension (ambulatory venous pressure greater than 42 mmHg) and in a group of normal subjects before and after treatment for four weeks with Total Triterpenic fraction of Centella Asiatica (TTFCA), a venoactive drug acting on the microcirculation and on capillary permeability. Group A (20 patients) was treated with TTFCA 60 mg tid; Group B (20 patients) was treated with 30 mg tid; Group C (12 patients) was treated with placebo; and Group D (10 normal subjects) was treated with TTFCA 60 mg tid in an open study. Capillary filtration rate was assessed by venous occlusion plethysmography, ankle edema by a new system called AECT (Ankle edema coin tester). Subjective symptoms of venous hypertension were assessed by an analogue scale line considering four symptoms: swelling sensation, restless lower extremity, pain and cramps, and tiredness. CFR, AC, and AE were significantly higher in patients in comparison with normal subjects. After four weeks of TTFCA treatment there was a significant decrease of the abnormally increased CFR, AC, and AECT time in patients. This was also greater in the higher dose group. No significant change was observed in the placebo group and in normal subjects treated with TTFCA. Symptoms were also significantly improved in the two groups treated with the active drug according to the dose. No significant changes were observed in the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)