Pharmacological treatment of Alzheimer disease: from psychotropic drugs and cholinesterase inhibitors to pharmacogenomics

For the past 20 years the scientific community and the pharmaceutical industry have been searching for treatments to neutralize the devastating effects of Alzheimer disease (AD). During this period important changes in the etiopathogenic concept of AD have occurred and, as a consequence, the pharmacological approach for treating AD has also changed. During the past 2 decades only 3 drugs for AD have been formally approved by the FDA, although in many countries there are several drugs which are currently used as neuroprotecting agents in dementia alone or in combination with cholinesterase inhibitors. The interest of the pharmaceutical industry has also shifted from the cholinergic hypothesis which led to the development of cholinesterase inhibitors to enhance the bioavailability of acetylcholine at the synaptic cleft to a more "molecular approach" based on new data on the pathogenic events underlying neurodegeneration in AD. In our opinion, the pharmacological treatment of AD should rely on a better understanding of AD etiopathogenesis in order to use current drugs that protect the AD brain against deleterious events and/or to develop new drugs specifically designed to inhibit and/or regulate those factors responsible for premature neuronal death in AD. The most relevant pathogenic events in AD can be classified into main categories: primary events (genetic factors, neuronal apoptosis), secondary events (beta-amyloid deposition in senile plaques and brain vessels, neurofibrillary tangles due to hyperphosphorylation of tau proteins, synaptic loss), tertiary events (neurotransmitter deficits, neurotrophic alterations, neuroimmune dysfunction, neuroinflammatory reactions) and quaternary events (excitotoxic reactions, calcium homeostasis miscarriage, free radical formation, primary and/or reactive cerebrovascular dysfunction). All of these pathogenic events are potential targets for treatment in AD. Potential therapeutic strategies for AD treatment include palliative treatment with nonspecific neuroprotecting agents, symptomatic treatment with psychotropic drugs for noncognitive symptoms, cognitive treatment with cognition enhancers, substitutive treatment with cholinergic enhancers to improve memory deficits, multifactorial treatment using several drugs in combination and etiopathogenic treatment designed to regulate molecular factors potentially associated with AD pathogenesis. This review discusses the conventional cholinergic enhancers (cholinesterase inhibitors, muscarinic agonists), noncholinergic strategies that have been developed with other compounds, novel combination drug strategies and future trends in drug development for AD treatment. Stem-cell activation, genetically manipulated cell transplantation, gene therapy and antisense oligonucleotide technology constitute novel approaches for the treatment of gene-related brain damage and neuroregeneration. The identification of an increasing number of genes associated with neuronal dysfunction along the human genome together with the influence of specific allelic associations and polymorphisms indicate that pharmacogenomics will become a preferential procedure for drug development in polygenic complex disorders. Furthermore, genetic screening of the population at risk will help to identify candidates for prevention among first-degree relatives in families with transgenerational dementia.

Danazol treatment of idiopathic myelofibrosis with severe anemia

BACKGROUND AND OBJECTIVE

Severe anemia is an important problem in patients with idiopathic myelofibrosis (IM). When other therapeutic measures are unsuccessful or not applicable, 40-50% favorable responses are obtained with androgen therapy. Oxymetholone is the drug usually employed, but good results have also been reported with danazol, although the experience is limited to a few patients. The aim of the present study was to evaluate the effect of danazol on the anemia of IM.

DESIGN AND METHODS

Seven out of 22 consecutive IM patients were eligible for danazol treatment because of severe anemia not treatable with (four cases) or refractory to (three cases) other therapies. Danazol (600-800 mg/day) was given orally for six months and thereafter progressively tapered to the minimum effective dose in responding patients or discontinued in non-responders. Complete response was considered cessation of transfusion requirements with normalization of hemoglobin (Hb) values; partial response was defined as a > 30% reduction in transfusional needs or an increase > 10 g/L in the Hb. The effect on platelet counts was also analyzed.

RESULTS

One patient splenectomized three years earlier achieved a complete response and three a partial response, giving an overall response rate of 57 %. A significant increase in platelet counts was also observed in three responders. The responses were first seen between three and six months after the start of treatment, which was usually well tolerated.

INTERPRETATION AND CONCLUSIONS

Danazol, given at an appropriate dosage for a sufficient time, is an effective treatment for a substantial proportion of IM patients with severe anemia without marked splenomegaly or who have been previously splenectomized.

Influence of serum from healthy or breast tumor-bearing women on the growth of MCF-7 human breast cancer cells

Sera from women healthy (HW) or with breast (BCW), ovarian or endometrial cancer, were added (10%) to the culture media of MCF-7 cells and cell proliferation assessed 4 days later to verify: a) whether sera from BCW, obtained before or 8 days after tumor ablaction, influence the proliferation of these cells, b) whether the effects of serum from BCW are specific for mammary tumor cells. Sera from BCW, but not sera from women with ovarian or endometrial cancer, increased MCF-7 cell proliferation in comparison with sera from HW. After surgical ablation of the breast tumors, serum's ability to increase MCF-7 cell proliferation decreased significantly. These effects cannot be explained by differences on serum levels of estradiol or melatonin. These results suggest the presence of growth-promoting substances of possible tumoral origin in serum of BCW, a fact that should be considered as support for the surgical treatment of tumor masses.

[Ethical considerations on human cloning. A psychoanalytic perspective]

A brief review of ethical issues related to two types of human cloning is presented: cloning embryonic cells not intended to culminate in the birth of a new individual and cloning human beings. Advantages and objections related to both types of human cloning are analyzed from an ethical point of view. Repercussions on individuals born by the technique of cloning are discussed from a psychoanalytical perspective. It can be concluded that cloning embryonic cells could be admissible, while not cloning considered as a reproductive option.

Cyclosporin A upmodulates the alpha-subunit of the interleukin-2 receptor and the metastatic ability of murine B16F10 melanoma cells

In the present study, the effect of in vitro cyclosporin A (CsA) treatment on IL-2R expression and the metastatic behavior of B16F10 melanoma cells has been reported. CsA treatment was found to increase the percentage of B16F10 cells expressing the alpha-subunit of IL-2R on the cell surface and also at the mRNA level. Moreover, CsA treated B16F10 cells also express the beta-subunit of IL-2. In vivo experiments showed that CsA increases the affinity of B16F10 metastazing cells for the liver and decreases that for the lung. CsA modulated the expression of MHC class I and class II antigens, but no significant differences in the resistance of CsA-treated B16F10 cells to NK lysis were observed. Finally, proliferation of B16F10 cells in the presence of several doses of CsA did not vary and CsA increased the amount of IL-1beta mRNA expression. These results suggest that CsA, through the modulation of cytokines and MHC antigen expression on B16F10 cells, could have an effect upon the metastatic progression of the B16F10 melanoma.

[Pathological laughter after the brainstem infarction]

We report a case of 'fou rire prodromique' heralding a brainstem infarct with favorable prognosis after thrombolysis. Different clinical forms of pathological laughter, the pathophysiological mechanisms and clinico-anatomical correlations of this rare phenomenon are discussed.

The cytolytic effect of a glycoconjugate extracted from corms of saffron plant (Crocus sativus) on human cell lines in culture

Corms of Crocus sativus L. (Iridaceae) contain a glycoconjugate that shows cytotoxic activity on tumoral cells in culture. Studies of intracellular calcium fluctuations, and release of lactate dehydrogenase in human cervical epitheloid carcinoma cells, showed that this compound caused plasma membrane damage, allowing movements of both calcium and macromolecules, and leading to cell lysis. Analysis of DNA fragmentation showed that cell death was not mediated by apoptosis. This molecule is active against human tumoral cells derived from fibrosarcoma, cervical epithelioid carcinoma and breast carcinoma, with IC50 values of 7, 9 and 22 micrograms/ml, respectively. The proteoglycan is about 8 times more cytotoxic for malignant cells than for their normal counterparts. In addition, 100 micrograms/ml of proteoglycan produced 50% in vitro lysis of normal human erythrocytes, whereas 320 micrograms/ml induced about 60% cell death on cultured human hair follicles. Altogether, these results suggests a distinctive cytotoxic activity of this molecule on different human cell types.

Relative sensitivity of direct antiglobulin test, antibody's elution and flow cytometry in the serologic diagnosis of immune hemolytic transfusion reactions

BACKGROUND AND OBJECTIVE

Current immunohematology practice dictates that serologic diagnosis of immune hemolytic transfusion reactions (IHTR) is based on the finding of a positive post-transfusion direct antiglobulin test (DAT). However, since DAT may fail to detect antibody-coated cells when they constitute a minor population amid a large number of non-sensitized ones, we investigated whether antibody detection in eluates or by flow cytometry is more sensitive than DAT in this context.

DESIGN AND METHODS

Ten samples of red blood cells sensitized with allo- or autoantibodies were diluted in non-sensitized red blood cells to final concentrations ranging from 10% to 0.1%. DAT, antibody detection in eluates, and immunofluorescence by flow cytometry were performed on each mixture.

RESULTS

DAT failed to detect sensitized cells in all but two cases in that only the 10% dilution yielded a positive DAT. Antibody detection in eluates and by flow cytometry was able to detect up to 1% sensitized cells in most cases.

INTERPRETATION AND CONCLUSIONS

Antibody detection in eluates and by flow cytometry is more sensitive than DAT for detecting minor populations of IgG-coated cells. These techniques should be included in the routine investigation of suspected cases of IHTR.

Inhibition of PKB/Akt1 by C2-ceramide involves activation of ceramide-activated protein phosphatase in PC12 cells

Accumulation of ceramide has been reported in stress- and receptor-induced apoptosis in the nervous system. However, its role in apoptosis signaling remains elusive. We describe here the inhibition of the NGF-activated phosphoinositide 3-kinase (PI3K)-PKB/Akt1 survival pathway by the cell permeable analog C2-ceramide. C2-ceramide did not inhibit ERK, PI3K, or PDK1 activities and did not alter the translocation of PDK1 and Akt1 to the plasma membrane, but blocked nuclear translocation of Akt1. Down-regulation of the Akt pathway was due to enhanced dephosphorylation of Akt1 at residues T308 and S473. Moreover, Akt1 was dephosphorylated in vitro by a cation-independent phosphatase involving ceramide-activated protein phosphatase (CAPP). Membrane-anchored Akt1 was more resistant to dephosphorylation/inactivation by C2-ceramide than wild-type Akt1. Consistently, N-myristylated-Akt1 conferred resistance to the apoptosis induced by C2-ceramide in PC12 cells. These results provide a novel mechanism for induction of apoptosis by ceramide in nerve-derived cells.

[Neurophysiological clinical study of 70 patients with type 2 spinocerebellar ataxia]

INTRODUCTION

The prevalence of hereditary ataxia in Holguín, Cuba, is 43 per 100,000 inhabitants, but in some regions reaches 503 per 100,000 inhabitants, a figure never previously recorded in the international literature.

OBJECTIVES

To evaluate the part played by non-cerebellar structures and vias in causing some of the clinical signs of the disorder by means of clinico-electro physiological correlation.

PATIENTS AND METHODS

A neurological examination, peripheral nerve conduction studies and somato-sensorial evoked potentials of the median and posterior tibial nerves were done in 70 patients with type 2 spinocerebellar ataxia.

RESULTS

The commonest clinical signs were ataxia on walking, dysarthria, dysmetria and adiadochokinesia. Correlation analysis showed that the variable most significantly correlated with the degree of ataxia and Romberg's sign was latency of the P40 component, whilst tendon reflexes were best correlated with H reflex latency. However, the duration of the disease was not found to have statistical correlation.

CONCLUSIONS

These results suggest that degeneration of long peripheral nerves and sensory paths contributes to the degree of ataxia and other clinical signs. At present no correlation has been found between the duration of the illness and increasing electrophysiological changes, and therefore seems not to have a major effect on neurodegenerative mechanisms.

Non-Hodgkin's lymphoma following untreated essential thrombocythemia

The coexistence of essential thrombocythemia (ET) and non-Hodgkin's lymphoma (NHL) is an extremely rare event, with only two such cases having been reported in the medical literature. We describe here a 25-year old woman who developed high-grade B-cell NHL of the stomach three years after the diagnosis of ET, for which she had received no treatment, due to her young age and the lack of thrombotic risk factors other than thrombocytosis. The lymphoma showed a favorable response to CHOP chemotherapy, whereas the thrombocytosis remained unchanged throughout the patient's clinical course. The possible etiologic and pathogenetic mechanisms leading to the association of these two disorders are discussed. Given the relative frequency of ET and the fact that the present case represents only the third reported instance of NHL developing in such patients, the coincidental ocurrence of both diseases is a possibility that cannot be excluded.

Phase II trial of vinorelbine in patients with advanced and/or recurrent cervical carcinoma: an EORTC Gynaecological Cancer Cooperative Group Study

The objective of this phase II study was to assess the efficacy and toxicity of vinorelbine administered as a single agent in the treatment of chemonaïve cervical cancer patients. 46 patients (41 eligible) with cervical cancer (epidermoid or adenocarcinoma) and measurable metastatic and/or recurrent disease localised outside irradiated areas were treated with weekly intravenous (i.v.) vinorelbine 30 mg/m2 infused over 20 min. No prior chemotherapy was allowed. Median age was 53 years (range: 33-73), and performance status 1 (0-2). 31 patients (76%) had prior radiation therapy. There were 7 partial responders (17, 95% confidence interval (CI) 7-32) and 8 stable diseases (20%). Median duration of response was 5 months (4-11). Granulocytopenia was the major toxicity, with 47% of patients exhibiting grade 3 or 4 toxicity. Dose reduction and/or treatment delay was necessary in 28 patients (78%). Peripheral neuropathy reported in 10 patients was mild (grade 1 in 9 patients and grade 2 in 1 patient). In conclusion, single agent vinorelbine has moderate activity in recurrent or metastatic cervical cancer, but its reduced neurotoxicity warrants further study in combination with cisplatin.

Antigenic and genetic characterization of a putative hybrid transferrin-binding protein B from Neisseria meningitidis

The transferrin-binding protein Bs (TbpBs) from the bacterium Neisseria meningitidis have been divided into two families according to genetic and antigenic features. TbpB from meningococcal strain B385 showed a molecular mass similar to that exhibited by TbpBs belonging to the high molecular mass family of TbpBs. TbpB was recognized by immunoassay using a specific serum directed against the TbpB of the reference strain for this family (strain M982). It was also recognized by a serum elicited against the TbpB of the reference strain for the low molecular mass family (strain B16B6). The tbpB gene from strain B385 was cloned and sequenced. The highest degree of sequence homology was found to be with the TbpBs belonging to the high molecular mass family, although a region of 14 amino acids that is only present in the TbpB from strain B16B6 was also found. This report illustrates a TbpB that shows hybrid antigenic and genetic behaviour.

Gastric antisecretory and antiulcer activities of an ethanolic extract of Bidens pilosa L. var. radiata Schult. Bip

Bidens pilosa var. radiata Schult. Bip. is used in folk medicine to treat stomach disorders including peptic ulcers. The ethanolic extract (0.5-2 g/kg) decreased the gastric juice volume, acid secretion, as well as pepsin secretion in pylorus ligated rats. B. pilosa extract showed antiulcer activity against indomethacin-induced gastric lesions. The extract effectively inhibited gastric haemorrhagic lesions induced by ethanol, and with an effective dose of 2 g/kg being more potent than sucralfate (400 mg/kg). In contrast, ranitidine (50 mg/kg) failed to reduce these lesions. These results indicate that B. pilosa ethanolic extract exerts a cytoprotective effect in addition to its gastric antisecretory activity that could be due, partly at least, to the presence of flavonoids of which quercetin was identified by HPLC.

Molecular modeling of the amyloid-beta-peptide using the homology to a fragment of triosephosphate isomerase that forms amyloid in vitro

The main component of the amyloid senile plaques found in Alzheimer's brain is the amyloid-beta-peptide (A beta), a proteolytic product of a membrane precursor protein. Previous structural studies have found different conformations for the A beta peptide depending on the solvent and pH used. In general, they have suggested an alpha-helix conformation at the N-terminal domain and a beta-sheet conformation for the C-terminal domain. The structure of the complete A beta peptide (residues 1-40) solved by NMR has revealed that only helical structure is present in A beta. However, this result cannot explain the large beta-sheet A beta aggregates known to form amyloid under physiological conditions. Therefore, we investigated the structure of A beta by molecular modeling based on extensive homology using the Smith and Waterman algorithm implemented in the MPsrch program (Blitz server). The results showed a mean value of 23% identity with selected sequences. Since these values do not allow a clear homology to be established with a reference structure in order to perform molecular modeling studies, we searched for detailed homology. A 28% identity with an alpha/beta segment of a triosephosphate isomerase (TIM) from Culex tarralis with an unsolved three-dimensional structure was obtained. Then, multiple sequence alignment was performed considering A beta, TIM from C.tarralis and another five TIM sequences with known three-dimensional structures. We found a TIM segment with secondary structure elements in agreement with previous experimental data for A beta. Moreover, when a synthetic peptide from this TIM segment was studied in vitro, it was able to aggregate and to form amyloid fibrils, as established by Congo red binding and electron microscopy. The A beta model obtained was optimized by molecular dynamics considering ionizable side chains in order to simulate A beta in a neutral pH environment. We report here the structural implications of this study.

[A cost-effectiveness analysis of strategies for the diagnosis-treatment of Helicobacter pylori-associated peptic ulcer in primary care]

OBJECTIVES

To undertake an economic evaluation of three strategies for diagnosing and treating Helicobacter pylori (HP)-related peptic ulcers (PU), and to find the most efficacious and efficient combination of medication for the most cost-effective strategy.

DESIGN

Cost-effectiveness analysis based on retrospective information (systematic review of the literature) and Markov models for the simulation of a hypothetical cohort of patients with PU.

PATIENTS

Patients seeking medical care at the primary level for an acute PU attack. The costs and health effects of the management of an attack were evaluated in a hypothetical cohort of adults (> 18 years old) with symptomatic peptic ulcer confirmed endoscopically and not associated with consumption of non-steroidal anti-inflammatory drugs (NSAIDs).

INTERVENTIONS

Three strategies for handling PU patients were compared: pre- and post-treatment diagnosis of HP, pre-treatment diagnosis and empirical treatment. Then the most efficient strategy for comparing 6 combinations of antibiotics was used.

RESULTS

The empirical treatment strategy was markedly less costly (saving of between 15000 and 39000 pesetas per patient treated) than the diagnosis strategies, and obtained equivalent effectiveness under all analytical hypotheses. In comparing drug combinations, the classic triple therapies based on bismuth subcitrate were more effective and less costly than other therapies.

CONCLUSIONS

Empirical treatment with combinations of irradicatory drugs was the most efficient strategy for tackling the diagnosis/therapy of patients with HP-related PU. In terms of efficiency, the choice between the various combinations of irradicatory drugs with over 80% success depends basically on the cost of the drugs.

Inhibition of tau phosphorylating protein kinase cdk5 prevents beta-amyloid-induced neuronal death

The key target of this study was the tau protein kinase II system (TPK II) involving the catalytic subunit cdk5 and the regulatory component p35. TPK II is one of the tau phosphorylating systems in neuronal cells, thus regulating its functions in the cytoskeletal dynamics and the extension of neuronal processes. This research led to demonstration that the treatment of rat hippocampal cells in culture with fibrillary beta-amyloid (Abeta) results in a significant increase of the cdk5 enzymatic activity. Interestingly, the data also showed that the neurotoxic effect of 1-20 microM Abeta on primary cultures markedly diminished with co-incubation of hippocampal cells with the amyloid fibers plus the cdk5 inhibitor butyrolactone I. This inhibitor protected brain cells against Abeta-induced cell death in a concentration dependent fashion. Moreover, death was also prevented by a cdk5 antisense probe, but not by an oligonucleotide with a random sequence. The cdk5 antisense also reduced neuronal expression of cdk5 compared with the random oligonucleotide. The studies indicate that cdk5 plays a major role in the molecular path leading to the neurodegenerative process triggered by the amyloid fibers in primary cultures of rat hippocampal neurons. These findings are of interest in the context of the pathogenesis of Alzheimer's disease.

Nonviral transfer of genes to pig primary keratinocytes. Induction of angiogenesis by composite grafts of modified keratinocytes overexpressing VEGF driven by a keratin promoter

Cultured epithelial grafts have proven to be life-saving in the treatment of large skin losses. It has become apparent that one of the main difficulties of this technology is the overall poor take of the grafts as a consequence of severely damaged dermal beds. Skin substitutes providing both cultured keratinocytes, as an epidermal layer, and a dermal analogous offer a more suitable material for skin repair. Ex vivo transfer of stroma regeneration-promoting genes to keratinocytes appears to be an attractive strategy for improving the therapeutic action of these grafts. The use of epidermal-specific promoters as expression drivers of exogenous genes results in both high expression levels and stratum specificity, as shown in transgenic mice studies. Most current gene transfer protocols to primary keratinocytes involve transduction of epidermal cells with retroviral vectors. However, transfer of gene constructs harboring these long DNA fragment promoters cannot be achieved through viral transduction. In this paper, we describe a protocol consisting of lipid-mediated transfection, G418 selection and an enhanced green fluorescence protein (EGFP)-based enrichment step for obtaining high levels of transgene-expressing primary keratinocytes. Using this protocol, the cDNA for vascular endothelial growth factor (VEGF), a potent endothelial cell mitogen driven by the 5.2 kb bovine keratin K5 promoter, was stably transfected into pig primary keratinocytes. Genetically modified keratinocytes, expanded on live fibroblast-containing fibrin gels and transplanted to nude mice as a composite material, elicited a strong angiogenic response in the host stroma as determined by fresh tissue examination and CD31 immunostaining. Since the formation of a well-vascularized wound bed is a crucial step for permanent wound closure, the use of an 'angiogenic' composite material may improve wound bed preparation and coverage with cultured keratinocyte grafts.

[The autologous transplantation of hematopoietic precursors on an outpatient basis: an analysis of its feasibility at the Hospital Clínic de Barcelona]

BACKGROUND

Autologous stem cell transplantation (ASCT) is increasingly performed on an outpatient basis. Preliminary results show a significant financial saving without modifying the therapeutic results. The aim of this study has been to evaluate the feasibility of this procedure in our the Hospital Clínic of Barcelona, Spain.

PATIENTS AND METHODS

All patients in whom an ASCT due to a hematological malignancy, having a good performance status, a caregiver 24 h per day, a lodging near to the hospital and an appropriate cultural and social environment, were offered an outpatient management starting the day after stem cell administration (day +1).

RESULTS

During the study period (April, 1997-June, 1998) 64 ASCT were performed. Fifteen patients (23%) were managed on an outpatient basis. The remaining patients were not included in the study due to patient preference (26%), medical reasons (22%), distant home (18%) and social problems (9%). Seven patients (47%) had to be readmitted in the hospital due to fever (n = 4), nausea (n = 2) or respiratory distress (n = 1). Patients receiving total body radiation (TBI) in the conditioning regimen did not have a higher readmission rate than those conditioned without TBI. The median hospital stay (since day +1) was 6 (range: 0-22) and 17 (13-117) days for outpatient and inpatients respectively (p = 0.0016). This reduction would imply a saving of 65% in hospitalization charges and of 12% in total charges. All patients having elected the outpatient management were very satisfied by having made that choice.

CONCLUSION

With an appropriate patient selection, outpatient ASCT is a feasible method that may improve the quality of life of the patients and can reduce the costs of the procedure.

Lack of association of MICA transmembrane region polymorphism and Behçet's disease in Spain

We have analyzed the distribution of the major histocompatibility complex (MHC) class I chain-related gene A (MICA) transmembrane alleles among 58 Spanish patients with Behçet's disease (BD) and in 194 ethnically matched healthy controls. The study included the characterization of A4, A5, A5.1, A6 "new" and "old" and A9 MICA-TM alleles using polymerase chain reaction. As previously reported, the serological B51 specificity was increased among this BD patient group (36.25% vs. 19.6% in controls; P=0.009; OR=2.33). The MICA-TM alleles A6 ("new" and "old"), in linkage disequilibrium with HLA-B51 and HLA-B14 respectively, were only slightly increased among patients (70.7% vs. 61.3% in controls; P=NS). We conclude that, in contrast to previous finding reporting a strong association of MICA-TM genes and Behçet disease in Japanese patients, in our population HLA-B51 is more closely associated to Behçet susceptibility than MICA-TM genes. Finally, our data show that in Spain, as occurs in other populations, some MICA-TM alleles exhibit strong linkage disequilibrium with certain alleles of the HLA-B locus.