A microcomputer-based data acquisition system for continuous recording of feeding and drinking by rats

A monitoring system to continuously record the daily pattern of drinking and eating of rats is described. This system, based on a North Star microcomputer, can record the amount of food ingested with a temporal resolution of +/- 1.0 second and quantitative accuracy within +/- 5%. Drinking behavior is detected using a drinkometer which also has a temporal resolution of +/- 1.0 second. Data are analyzed by computer to determine absolute amounts of consumption and patterns of intake. The patterns of feeding and drinking recorded by this system are similar to those observed using other monitoring devices.     

Rat self administration of ethanol: Enhancement by darkness and exogenous melatonin

Using an FT 60 schedule, rats on 100% free feeding tested in the dark phase of a 12:12 light-dark cycle were trained to self-administer ethanol intravenously. The effect was dose-dependent with 20% ethanol being the preferred dose as measured by the number of infusions. Daily administration of 1.5 mg/kg melatonin significantly increased ethanol self-injection in the dark but not in the light. The time of day of testing and/or drug administration may be an important variable in studies on self-administration of drugs. Testing in the dark may eliminate the need for reducing body weight when inducing self-administration of ethanol.     

A novel ELISpot method for adherent cells

The purpose of this study was to develop an enzyme-linked immunospot assay (ELISpot assay) that can be used with human adherent cells. While standard enzyme-linked immunosorbent assays (ELISAs) are available and widely used and ELISpot assays are used for nonadherent lymphocytes, no ELISpot assay has been developed for adherent cells. We used primary human fibroblasts from four different tissues (myometrium, lung, gingiva, and orbit), either unstimulated or interleukin (IL)-1beta-activated, to evaluate an ELISpot assay. Antibody pairs for IL-6 and IL-8 were used and results were compared to a standard ELISA. We found that we could reliably detect IL-6 and IL-8 spots with as few as 10 fibroblasts. Optimal cell numbers were 50 cells per well incubated for 8 h, although spots appeared as early as 2 h after incubation. Spots were absent when cells, primary, or secondary anti-cytokine antibodies were omitted from the protocol. Spot number and size can be ascertained using current automated ELISpot reader technology. The frequency of IL-6 and IL-8-producing human fibroblasts could also be determined. For example, 60% of the lung fibroblasts express IL-6, but IL-8 can be detected from only 40% of the cells. Approximately 80% of the human orbital fibroblasts make IL-6, whereas approximately 50% generate IL-8 following IL-1beta stimulation. These new findings show that fibroblasts from different human tissues display different frequencies of cytokine production and this further supports the concept of fibroblast diversity. The sensitivity of this new ELISpot assay is adequate for cytokine detection in just a few cells, unlike the standard ELISA. It should permit ascertaining the frequency of fibroblasts and other adherent cells that produce cytokines and, if desired, can be used in tandem with a standard ELISA to determine total cytokine produced. Moreover, the assay is suitable for normal human adherent cells that are often short-lived and difficult to cultivate.     

Abnormal expression of the cell cycle regulators P16 and CDK4 in Alzheimer's disease.

In this study, we demonstrate that two important regulators of the cell cycle, cyclin-dependent kinase-4 and its inhibitor p16, are increased in the brains of cases of Alzheimer's disease patients compared with age-matched controls. Both proteins are increased in the pyramidal neurons of the hippocampus, including those neurons containing neurofibrillary tangles and granulovacuolar degeneration. As p16 is not normally found in terminally differentiated neurons, it seems paradoxical that it is increased in Alzheimer's disease unless it is responding to increases in cyclin-dependent kinase-4 or other cell cycle regulators. Induction of the latter, a protein that signals re-entry and progression through the cell cycle, may itself be the consequence of alpha response to a growth stimulus. Re-entry into the cell cycle is likely deleterious in terminally differentiated neurons and may contribute to the biochemical abnormalities, such as oxidative stress and hyperphosphorylated tau protein, as well as the neuronal degeneration characteristic of the pathology of Alzheimer's disease.     

Signaling mechanisms regulating self-renewal and differentiation of pluripotent embryonic stem cells

An ability to propagate pluripotent embryonic cells in culture is the foundation both for defined germline modification in experimental rodents and for future possibilities for broad-based cellular transplantation therapies in humans. Yet, the molecular basis of the self-renewing pluripotent phenotype remains ill-defined. The relationship between factors that influence embryonic stem cell propagation in vitro and mechanisms of stem cell regulation operative in the embryo is also uncertain. In this article we discuss the role of intracellular signalling pathways in the maintenance of pluripotency and induction of differentiation in embryonic stem cell cultures and the mammalian embryo.     

Congenital cytomegalovirus infection.

The overall prevalence of congenital cytomegalovirus infection among the offspring of a highly immune young female population was 2.4 per cent (23 of 939). To ascertain whether the presence of anticytomegalovirus antibodies protects the developing fetus, we examined the offspring of 239 prospectively studied women. Despite substantial levels of preconceptional antibodies, intrauterine cytomegalovirus infection occured in seven of 208 (3.4 per cent) seroimmune women. Three neonates with congenital infection were born to 31 initially seronegative women. All the congenitally infected infants had subclinical involvement. Maternal humoral immunity may not protect the fetus against congenital cytomegalovirus infection. Neutralization kinetics and restriction enzyme analysis with endonucleases (EcoR-1 and HinD 111) demonstrated antigenic and genetic homology between viral strains isolated from two siblings consecutively infected in utero, indicating that repeat maternal infection with the same virus is transmissible to sequential products of conception.     

Replacing the academic medical center's teaching hospital.

Addressing the need for updated teaching hospital facilities is one of the most significant issues that an academic medical center faces. The authors describe the process they underwent in deciding to build a new facility at the Medical University of South Carolina (MUSC). Initial issues included whether or not the teaching hospital would continue to play a role in clinical education and whether to replace or renovate the existing facility. Once the decision to build was reached, MUSC had to choose between an on-campus or distant site for the new hospital and determine what the function of the old hospital would be. The authors examine these questions and discuss the factors involved in different stages of decision making, in order to provide the academic medicine community guidance in negotiating similar situations. Open communication within MUSC and with the greater community was a key component of the success of the enterprise to date. The authors argue that decisions concerning site, size, and focus of the hospital must be made by developing university-wide and community consensus among many different constituencies. The most important elements in the success at MUSC were having unified leadership, incorporating constituent input, engaging an external consultant, remaining unfazed by unanticipated challenges, and adhering to a realistic, aggressive timetable. The authors share their strategies for identifying and successfully managing these complex and potentially divisive aspects of building a new teaching hospital.     

Abundance of Ixodes scapularis (Acari: Ixodidae) after the complete removal of deer from an isolated offshore island, endemic for Lyme Disease

Monhegan is an isolated 237-ha island lying 16 km off the coast of Maine. Introduced to the island in 1955, white-tailed deer, Odocoileus virginianus Zimmerman, reached a density of approximately 37/km2 by the mid-1990s. Black-legged ticks, Ixodes scapularis Say, first noticed in the late 1980s, flourished thereafter. Norway rats (Rattus norvegicus Berkenhout) on Monhegan are highly infected with Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt, and Brenner, the agent of Lyme disease. By 1996, 13% of year-round residents had contracted the disease. The community's subsequent decision to eliminate deer from the island provided a unique opportunity to monitor the abundance of vector ticks in response to the complete and permanent removal of the primary hosts of their reproductive stage. With the exception of humans and their dogs and cats, there are no other potential hosts for adult I. scapularis on Monhegan. From November 1996 to March 1999, all deer were removed from the island. Previous annual fall flagging of vegetation from 1990 to 1998 produced 6-17 adult ticks/h, of which 24-41% were infected with the Lyme disease spirochete. During this same period, up to 18 larvae and 4 nymphs were removed per Norway rat live-trapped on the island each July. With the absence of deer in the fall of 1999, both the density of host-seeking adult ticks and infection prevalence rose substantially to 28/h and 75.0%, respectively. By the summer of 2003, however, no sub-adult ticks were found on rats, and that fall, only 0.67 adult ticks/h were flagged. Of the 68 adults collected from 2002 to 2003, 20 (29.4%) were infected. Over this same period, adult tick abundance on a deer-populated, reference island continued to gradually increase.