Geroscience and Alzheimer's Disease Drug Development

Age is the most important risk factor for Alzheimer's disease (AD). The acceptable age range for participation in AD clinical trials is 50 to 90, and this 40-year span incorporates enormous age-related change. Clinical trial participants tend to be younger and healthier than the general population. They are also younger than the general population of AD patients. Drug development from a geroscience perspective would take greater account of effects of aging on clinical trial outcomes. The AD clinical trial pipeline has diversified beyond the canonical targets of amyloid beta protein and tau. Many of these interventions apply to age-related disorders. Anti-inflammatory agents and bioenergetic and metabolic therapies are among the well represented classes in the pipeline and are applicable to AD and non-AD age-related conditions. Drug development strategies can be adjusted to better inform outcomes of trials regarding aged individuals. Inclusion of older individuals in the multiple ascending dose trials of Phase 1, use of geriatric-related clinical outcomes and biomarkers in Phase 2, and extension of these Phase 2 learnings to Phase 3 will result in a more comprehensive understanding of AD therapies and their relationship to aging. Clinical trials can employ a more comprehensive geriatric assessment approach and biomarkers more relevant to aging at baseline and as exploratory outcomes. Greater attention to the role of aging and its influence in AD clinical trials can result in better understanding of the generalizability of clinical trial findings to the older AD population.

Indications of an electronic phase transition in two-dimensional superconducting YBa2Cu3O(7-x) thin films induced by electrostatic doping

We successfully tuned an underdoped ultrathin YBa2Cu3O(7-x) film into the overdoped regime by means of electrostatic doping using an ionic liquid as a dielectric material. This process proved to be reversible. Transport measurements showed a series of anomalous features compared to chemically doped bulk samples and a different two-step doping mechanism for electrostatic doping was revealed. The normal resistance increased with carrier concentration on the overdoped side and the high temperature (180 K) Hall number peaked at a doping level of p∼0.15. These anomalous behaviors suggest that there is an electronic phase transition in the Fermi surface around the optimal doping level.

Viscoelastic Properties of Healthy Human Artery Measured in Saline Solution by AFM-Based Indentation Technique

Using an Atomic Force Microscope with an attachment for indentation, we have measured local, in vitro mechanical properties of healthy femoral artery tissue held in saline solution. The elastic modulus (34.3 kPa) and viscoelastic response (τɛ = 16.9 s and τσ = 29.3 s) of the unstretched, intimal vessel wall have been determined using Sneddon theory and a three element model (standard linear solid) for viscoelastic materials. The procedures necessary to employ the indenting attachment to detect elastic moduli in the kPa range in liquid are described.

Nutrition support in clinical practice: review of published data and recommendations for future research directions

In the last 30 years, marked advances in enteral feeding techniques, venous access, and enteral and parenteral nutrient formulations have made it possible to provide nutrition support to almost all patients. Despite the abundant medical literature and widespread use of nutritional therapy, many areas of nutrition support remain controversial. Therefore, the leadership at the National Institutes of Health, The American Society for Parenteral and Enteral Nutrition, and The American Society for Clinical Nutrition convened an advisory committee to perform a critical review of the current medical literature evaluating the clinical use of nutrition support; the goal was to assess our current body of knowledge and to identify the issues that deserve further investigation. The panel was divided into five groups to evaluate the following areas: nutrition assessment, nutrition support in patients with gastrointestinal diseases, nutrition support in wasting diseases, nutrition support in critically ill patients, and perioperative nutrition support. The findings from each group are summarized in this report. This document is not meant to establish practice guidelines for nutrition support. The use of nutritional therapy requires a careful integration of data from pertinent clinical trials, clinical expertise in the illness or injury being treated, clinical expertise in nutritional therapy, and input from the patient and his/her family.

Nutrition support in clinical practice: review of published data and recommendations for future research directions. Summary of a conference sponsored by the National Institutes of Health, American Society for Parenteral and Enteral Nutrition, and American Society for Clinical Nutrition

In the last 30 years, marked advances in enteral feeding techniques, venous access, and enteral and parenteral nutrient formulations have made it possible to provide nutrition support to almost all patients. Despite the abundant medical literature and widespread use of nutritional therapy, many areas of nutrition support remain controversial. Therefore, the leadership at the National Institutes of Health, The American Society for Parenteral and Enteral Nutrition, and The American Society for Clinical Nutrition convened an advisory committee to perform a critical review of the current medical literature evaluating the clinical use of nutrition support; the goal was to assess our current body of knowledge and to identify the issues that deserve further investigation. The panel was divided into five groups to evaluate the following areas: nutrition assessment, nutrition support in patients with gastrointestinal diseases, nutrition support in wasting diseases, nutrition support in critically ill patients, and perioperative nutrition support. The findings from each group are summarized in this report. This document is not meant to establish practice guidelines for nutrition support. The use of nutritional therapy requires a careful integration of data from pertinent clinical trials, clinical expertise in the illness or injury being treated, clinical expertise in nutritional therapy, and input from the patient and his/her family. (Journal of Parenteral and Enteral Nutrition 21:133-156, 1997).

Nutrition support in clinical practice: review of published data and recommendations for future research directions. National Institutes of Health, American Society for Parenteral and Enteral Nutrition, and American Society for Clinical Nutrition

In the last 30 years, marked advances in enteral feeding techniques, venous access, and enteral and parenteral nutrient formulations have made it possible to provide nutrition support to almost all patients. Despite the abundant medical literature and widespread use of nutritional therapy, many areas of nutrition support remain controversial. Therefore, the leadership at the National Institutes of Health, The American Society for Parenteral and Enteral Nutrition, and The American Society for Clinical Nutrition convened an advisory committee to perform a critical review of the current medical literature evaluating the clinical use of nutrition support; the goal was to assess our current body of knowledge and to identify the issues that deserve further investigation. The panel was divided into five groups to evaluate the following areas: nutrition assessment, nutrition support in patients with gastrointestinal diseases, nutrition support in wasting diseases, nutrition support in critically ill patients, and perioperative nutrition support. The findings from each group are summarized in this report. This document is not meant to establish practice guidelines for nutrition support. The use of nutritional therapy requires a careful integration of data from pertinent clinical trials, clinical expertise in the illness or injury being treated, clinical expertise in nutritional therapy, and input from the patient and his/her family.

Transmission of Citrobacter koseri from mother to infant documented by ribotyping and pulsed-field gel electrophoresis

We describe a case in which Citrobacter koseri (formerly C. diversus) was transmitted from a pregnant mother with chorioamnionitis and bacteremia to her infant who was bacteremic at birth and in apparent septic shock. Two highly discriminating molecular methods, ribotyping and pulsed field gel electrophoresis, were used to examine restriction fragment length polymorphisms within the genomic DNA of maternal and infant isolates. Both techniques identified the maternal and infant isolates as the same strain, distinct from epidemiologically unrelated controls, thus confirming their common origin.

Magnetic resonance imaging of trabecular bone structure in the distal radius: relationship with X-ray tomographic microscopy and biomechanics

The contribution of trabecular bone structure to bone strength is of considerable interest in the study of osteoporosis and other disorders characterized by changes in the skeletal system. Magnetic resonance (MR) imaging of trabecular bone has emerged as a promising technique for assessing trabecular bone structure. In this in vitro study we compare the measures of trabecular structure obtained using MR imaging and higher-resolution X-ray tomographic microscopy (XTM) imaging of cubes from human distal radii. The XTM image resolution is similar to that obtained from histomorphometric sections (18 microns isotropic), while the MR images are obtained at a resolution comparable to that achievable in vivo (156 x 156 x 300 microns). Standard histomorphometric measures, such as trabecular bone area fraction (synonymous with BV/TV), trabecular width, trabecular spacing and trabecular number, texture-related measures and three-dimensional connectivity (first Betti number/volume) of the trabecular network have been derived from these images. The variation in these parameters as a function of resolution, and the relationship between the structural parameters, bone mineral density and the elastic modulus are also examined. In MR images, because the resolution is comparable to the trabecular dimensions, partial volume effects occur, which complicate the segmentation of the image into bone and marrow phases. Using a standardized thresholding criterion for all images we find that there is an overestimation of trabecular bone area fraction (approximately 3 times), trabecular width (approximately 3 times), fractal dimension (approximately 1.4 times) and first Betti number/ volume (approximately 10 times), and an underestimation of trabecular spacing (approximately 1.6 times) in the MR images compared with the 18-microns XTM images. However, even for a factor of 9 difference in spatial resolution, the differences in the morphological trabecular structure measures ranged from a factor of 1.4 to 3.0. We have found that trabecular width, area fraction, number, fractal dimension and Betti number/volume measured from the XTM and MR images increases, while trabecular spacing decreases, as the bone mineral density and elastic modulus increase. A preliminary bivariate analysis showed that in addition to bone mineral density alone, the Betti number, trabecular number and spacing contributed to the prediction of the elastic modulus. This preliminary study indicates that measures of trabecular bone structure using MR imaging may play a role in the study of osteoporosis.

Efficacy and pharmacokinetics of intravenous immune globulin administration to high-risk neonates

OBJECTIVE--To determine whether intravenous immune globulin (IVIG) administration modifies the incidence of infections in high-risk neonates. DESIGN--Randomized, double-blind study. SETTING--Neonatal intensive care unit at a tertiary care center.

PARTICIPANTS

A total of 170 infants were enrolled, 82 of whom received IVIG and 88 of whom received the placebo preparation. Infants were stratified by birth weight into one of three groups (category 1, those weighing less than 1000 g; category 2, those weighing between 1000 and 1500 g; and category 3, those weighing more than 1500 g). INTERVENTIONS--Intravenous immune globulin (750 mg/kg of body weight), or albumin placebo was administered within 72 hours of admission to the tertiary care center and every 14 days thereafter until discharge from the neonatal intensive care unit or age 3 months. Serum IgG levels were measured and data collected relating to the incidence of systemic and localized infections and to the course of hospitalization. MEASUREMENTS AND MAIN RESULTS--The administration of IVIG had no major side effects and resulted in higher serum IgG levels in infants in all birth weight categories compared with infants receiving the placebo. Systemic infections developed in five IVIG-treated infants and five placebo-treated infants. Administration of immunoglobulin had no significant effect on the rate of localized infections or necrotizing enterocolitis. It also did not affect hospital course of the infants as measured by length of hospitalization or the number of days on assisted ventilation, supplemental oxygen, or antibiotics was required. CONCLUSIONS--The general administration of IVIG using this dosage regimen has limited effects on the clinical course of infants in a neonatal intensive care unit.

High-level secretion of biologically active aprotinin from the yeastPichia pastoris

A synthetic gene encoding aprotinin (bovine pancreatic trypsin inhibitor) was fused to the Saccharomyces cerevisiae prepro alpha mating factor leader sequence at the dibasic amino acid processing site. Pichia pastoris strains were developed to express one or multiple copies of a methanol-inducible expression cassette containing the gene fusion. P. pastoris containing a single copy of the vector secreted approximately 150 mg/l of immunoreactive protein. A construct bearing five copies of the expression cassette secreted 930 mg/l of aprotinin. The purified aprotinin molecule was equipotent with the native molecule in a trypsin inhibition assay. Protein sequence analysis showed that the alpha factor-aprotinin fusion was not processed at the basic amino acid residues Lys-Arg. Instead, recombinant aprotinin had additional N-terminal amino acids derived from prepro alpha factor. The N-terminal extension was variably 11 or 4 amino acids. Inclusion of the spacer DNA sequence encoding Glu and Ala between aprotinin and the Lys-Arg processing site led to the secretion of a biologically active aprotinin containing only a Glu-Ala N-terminal extension.

Immunoglobulins and other modalities for the prevention and treatment of enteric viral infections

Viral infections of the gastrointestinal tract constitute a major health problem during the first years of life. In addition to causing acute diarrhea, rotaviruses and other enteric viruses may be involved in the pathogenesis of necrotizing enterocolitis and other neonatal enteric diseases. There are several potential methods for the prevention and treatment of gastrointestinal viral infections. Antiviral immune globulins, administered by the parenteral or oral route, might prove useful for the inhibition of intestinal viral replication. Alternatively, specific glycoprotein inhibitors of viral-cell binding might be used to prevent the productive infection of intestinal epithelial cells. In addition, since many enteric viruses require proteolytic enzymes for protein cleavage, protease inhibitors may prove to be effective agents for the inhibition of intestinal viral replication. At this point in time, these methods have proven useful for the inhibition of rotavirus infection in experimental animals. The successful application of these and other methods for the prevention of enteric infections in humans might substantially reduce the morbidity and mortality associated with enteric diseases.

Epidemiology and potential methods for prevention of neonatal intestinal viral infections

Viral infections of the gastrointestinal tract remain a major problem during the neonatal period. In addition to causing acute diarrhea, rotaviruses and other enteric viruses may be involved in the pathogenesis of necrotizing enterocolitis and other neonatal enteric diseases. There are several potential methods for the prevention and treatment of gastrointestinal viral infections. Antiviral immunoglobulins might be used to inhibit intestinal viral replication. Since only small concentrations of serum immunoglobulins are present at mucosal surfaces, oral administration of immunoglobulins might be utilized to maximize antiviral efficacy. Alternatively, inhibitors of specific glycoproteins of virus-cell binding might be used to prevent the productive infection of intestinal epithelial cells. In addition, since many enteric viruses require proteolytic enzymes for protein cleavage, protease inhibitors may prove effective for inhibition of intestinal viral replication. At this time, these methods have proven useful for the inhibition of rotavirus infection in experimental animals. The successful application of these and other methods for the prevention of enteric infections in humans might substantially reduce the morbidity and mortality associated with enteric diseases in high-risk neonates.

Identification of a group-reactive epitope of group B rotaviruses recognized by monoclonal antibody and application to the development of a sensitive immunoassay for viral characterization

Group B rotaviruses (GBRs) are fastidious agents which cause enteric disease in humans and a number of other animal species. Detailed study of the role of GBRs in human disease has been hampered by the lack of immunoreagents suitable for large-scale studies. We developed a monoclonal antibody which recognizes a group-reactive antigen contained in a number of strains of GBRs. When utilized in conjunction with a hyperimmune guinea pig antiserum to GBR, this monoclonal antibody can be used in an enzyme immunoassay system to detect a wide range of GBRs. Alternatively, this monoclonal antibody can be combined with sera obtained from GBR-infected animals to devise assays which are largely specific for the homologous strain of GBR. Reactivity was not noted in either system with strains of group A or group C rotaviruses or with other members of the family Reoviridae. These results indicate that GBRs contain both group-reactive and species-specific antigens which are distinct from those found in group A rotaviruses. The availability of well-defined immunoreagents will facilitate detailed studies of GBR infections in humans and animals.

Ventilatory physiology of patients with panic disorder

Thirty-one patients with DSM-III panic disorder or agoraphobia with panic attacks, 13 normal controls, and 12 patients with other anxiety disorders were studied during ventilatory challenge with room air hyperventilation and 5% carbon dioxide inhalation. Patients also underwent sodium lactate infusion. Among the patients with panic disorder, 58% panicked with sodium lactate, 39% with 5% CO2, and 23% with room air hyperventilation. Of the other patients, four panicked with sodium lactate, none with 5% CO2, and one with room air hyperventilation. One normal control panicked with both sodium lactate and 5% CO2. Panic with CO2 was associated with an exaggerated ventilatory response and increases in plasma norepinephrine level and diastolic blood pressure. Patients with panic disorder may have hypersensitive CO2 receptors that, when triggered, evoke a subjective panic associated with an exaggerated ventilatory response and consequent hypocapnic alkalosis.

Tremorous mouth movements in rats administered chronic neuroleptics

Oral movements (OMs) in rats administered chronic haloperidol (HAL) were quantified simultaneously by a human observer and via a computerized video analysis system which monitored the distance between the upper and low lips using TV images. The human observer data indicated that during HAL administration the total duration of OMs was initially decreased, gradually returned to levels slightly above controls, and then increased substantially upon drug withdrawal. The computer records confirmed these findings and further indicated that after prolonged HAL administration a syndrome developed in which large-amplitude OMs remained suppressed but OMs of the smallest detectable amplitudes increased. Upon drug withdrawal, these small OMs increased in amplitude and rhythmicity, developing into repetitive tremors.

Impediments to Alcohol Education

Two major forces mitigate against alcoholism education within the medical school curriculum. One relates to the structure and organization of academic medicine with its emphasis on disease states and pathophysiology; sophisticated and technologically complex diagnostic and treatment modalities; and an acute illness, cure-oriented focus rather than a chronic illness, adaptational approach to illness. The second constellation of factors relates to the alcoholism field's failure to identify with other issues in medical education that similarly challenge the Flexnerian curriculum; the lack of a conceptual basis for defining the physician-alcoholism specialist in relation to other medical disciplines; the clinical treatment field's competing craft and professional orientations; and the absence of a scientific vocabulary suited to the existing biopsychosocial paradigms. It is suggested that these impediments could be overcome if the alcoholism field defined the model for managing chronic illness that is implicit in alcoholism treatment.

Relapse among alcoholics who are alcoholism counselors

The incidence of relapse among alcoholics who are alcoholism counselors, their agency's response to this and the implications for patient care and personnel practices are examined.