S.T. St. Jeor

D2 dopamine receptor gene and cigarette smoking: A reward gene?

There is now growing evidence that the less prevalent allele (A1) of the D2 dopamine receptor (DRD2) gene is strongly associated with severe alcoholism. Similarly, subjects who abuse illegal drugs or who are obese also show a significantly higher prevalence of the A1 DRD2 allele compared to controls. Moreover, cigarette smokers, both past and current, demonstrate significantly higher prevalence of the A1 allele than nonsmokers. In as much as alcohol, cocaine, opiates, nicotine and food are known to increase brain dopamine levels and activate the mesocorticolimbic dopaminergic reward pathways of the brain, it is hypothesized that an inherited deficit of D2 dopamine receptor numbers in brain reward areas of A1 allelic subject predisposes them to substance abuse problems.

Characterization of an Antisense Transcript Spanning the UL81-82 Locus of Human Cytomegalovirus

ABSTRACT In this study we present the characterization of a novel transcript, UL81-82ast, UL81-82 antisense transcript, and its protein product. The transcript was initially found in a cDNA library of monocytes from a seropositive donor. mRNA was obtained from monocytes isolated from a healthy donor with a high antibody titer against human cytomegalovirus (HCMV). The mRNAs were cloned into a lambda phage-derived vector to create the cDNA library. Using PCR, UL81-82ast was amplified from the library. The library was tested for the presence of numerous HCMV genes. Neither structural genes nor immediate-early genes were found. UL81-82ast was detected in five bone marrow samples from healthy antibody-positive donors. This same transcript was also found in in vitro-infected human fibroblasts early after infection but disappears at the same time that UL82 transcription begins. Not only was the transcript amplified using reverse transcription-PCR and sequenced but its protein product (UL82as protein) was detected by both Western blot and immunofluorescence. Phylogenetic studies using UL82as protein were conducted, showing a high degree of conservation in clinical isolates, laboratory strains of HCMV, and even in chimpanzee CMV. The transcript could be involved in the posttranscriptional regulation of the UL82 gene, affecting its mRNA stability or translation. Since the UL82 product, pp71, functions as an immediate-early transactivator, its posttranscriptional control could have some effect over latency reactivation and lytic replication.

Generation of a life-expanded rhesus monkey fibroblast cell line for the growth of rhesus rhadinovirus (RRV).

Summary. RRV, the rhesus macaque equivalent to HHV-8 or kaposi’s sarcoma-associated herpesvirus (KSHV) was recently isolated from a simian immuno-deficiency virus (SIV) infected macaque with a lymphoproliferative disorder. The growth of RRV in tissue culture requires propagation of primary rhesus monkey fibroblasts (RFs). In an effort to extend the life of these primary cells in tissue culture, the catalytic subunit of telomerase (hTERT) was introduced into RF cells using a recombinant retrovirus. This new cell line, Telo-RFs, have currently been passed in tissue culture over 80 times compared to a maximum passage number of 38 for wild type RFs, remain fully permissive for RRV DNA replication and production of infectious virus. Viral gene expression of immediate-early and early RNA transcripts was virtually identical to that observed in wild-type (wt) RFs. In addition, transfection experiments show that telo-RFs are easily and more efficiently transfected than wtRFs.

Phylogenetic relationships of dengue-1 viruses from Argentina and Paraguay.

Summary. We sequenced the Capsid-pre Membrane (C/prM) and the Envelope-Nonstructural protein 1 (E/NS1) regions of 24 recent isolates of dengue-1 (DEN-1) from South America. This included 12 Argentinean and 11 Paraguayan DEN-1 strains isolated in 2000 plus a Paraguayan strain isolated in 1988. These sequences were compared with published sequences of DEN-1 isolated worldwide to determine the origin of these isolates. Pairwise comparisons of strains from Paraguay and Argentina revealed a nucleotide divergence of 0–5% in the E/NS1 region and 0–3% in the C/prM region. Our results showed that these viruses belong to the same genotype, but can be separated into two clades. Interestingly, both clades circulated simultaneously in the same geographic area during the 2000 outbreaks. Amino acid differences were found between both clades in the C/prM region at position 100 (Lys vs. Arg) and in the E/NS1 region at positions 722 (Ala vs. Thr). Although the geographic movement of DEN-1 virus can not be unequivocally traced from the genetic relationship determined here, our results suggest that the recent epidemics in Argentina and Paraguay were due to the re-emergence of a previously circulating strain, or to the virus circulating unnoticed, rather than to the introduction of a new genotype.

Perivascular Stromal Cells as a Potential Reservoir of Human Cytomegalovirus

Human cytomegalovirus (HCMV) infection is an important cause of morbidity and mortality among both solid organ and hematopoietic stem cell transplant recipients. Identification of cells throughout the body that can potentially serve as a viral reservoir is essential to dissect mechanisms of cell tropism and latency and to develop novel therapies. Here, we tested and compared the permissivity of liver‐, brain‐, lung (LNG)‐ and bone marrow (BM)‐derived perivascular mesenchymal stromal cells (MSC) to HCMV infection and their ability to propagate and produce infectious virus. Perivascular MSC isolated from the different organs have in common the expression of CD146 and Stro‐1. While all these cells were permissive to HCMV infection, the highest rate of HCMV infection was seen with LNG‐MSC, as determined by viral copy number and production of viral particles by these cells. In addition, we showed that, although the supernatants from each of the HCMV‐infected cultures contained infectious virus, the viral copy number and the quantity and timing of virus production varied among the various organ‐specific MSC. Furthermore, using quantitative polymerase chain reaction, we were able to detect HCMV DNA in BM‐MSC isolated from 7 out of 19 healthy, HCMV‐seropositive adults, suggesting that BM‐derived perivascular stromal cells may constitute an unrecognized natural HCMV reservoir.

Prevention of Weight Gain through the Holidays

Abstract LEARNING OUTCOME: To test whether a liquid meal replacement plan can prevent weight gain during the holidays. It is a commonly held belief that Americans gain weight over the holidays (Thanksgiving to New Years), even though reliable data on holiday weight changes does not appear in recent literature. Retention of even small amounts of weight following every holiday season could contribute significantly to overall weight gain. The objective of this study was to apply a maintenance strategy which involved exchanging two regular meals with a commercial liquid meal replacement for each holiday eating event, such as parties and dinners, from Dec 15 to Jan 15. Male and female subjects (Ss) selected from a university population included staff, faculty, and students 25-60 years old Ss were randomized into treatment (N=27) and control (N=31) groups and matched by weight using a BMI of >27 for overweight. All Ss were given a baseline questionnaire designed to determine weight loss history including questions about their usual holiday weight gain. Ss reported to the clinic for a fasted morning weigh-in at the start and finish of the 4 week period. Control Ss tracked their holiday meals while treatment Ss tracked meal replacements, body weight, holiday-related eating events, and the perceived effectiveness of seven weight maintenance statements. Treatment Ss consumed an average of 16.3±7.8 meal replacement beverages during the study period. Treatment Ss lost 0.06+2.81bs while control Ss gamed 1.36±2.6 lbs (p

Teaching Nutrition Assessment to First Year Medical Students in a Practice Setting

Abstract LEARNING OUTCOME: To describe a method for integrating nutrition assessment and demonstrating its relevance in the primary care medical curriculum. In order provide medical students with earlier exposure to patients and generalist medicine an Introduction to Patient Care course was recently added to the curriculum. First and second year students learn basic interviewing and examination skills through didactic sessions and once a week participation with a generalist MD preceptor in their practice office. As part of this course, the students were given a nutrition assignment to be completed with a patient in the preceptors office. The timing was optimal in that a medical nutrition course was being taught concurrently. The objective for the assignment was to involve students and preceptors in nutrition assessment and counseling using practical tools and techniques. Each student discussed the assignment with their preceptor, selected a patient willing to fill out a questionnaire and food frequency and discuss nutrition recommendations, and submitted a write up of pertinent background information along with copies of the completed questionnaires and recommendations provided to their patient. All 51 students completed the assignment selecting patients ranging in age from 3 months to 79 years. The majority (78%) were regular office patients being seen for on-going care of an existing illness, well check ups, or treatment of a new illness or injury, and the remainder were co-workers or friends. One fourth of the patients selected had no diagnosis listed, but common diagnoses among others included diabetes, overweight, thyroid conditions and hypertension. Forty one of the students included the patients height and weight in their write up, but only 14 evaluated weight status. Most of the students (63%) chose to actively interview the patients using the questionnaires instead of having the patients fill them out themselves. Thoroughness of the write ups varied: 90% included some social history, 47% family history of disease, 71% medications, 59% exercise habits, and 59% included pertinent lab values. Eleven of the students used a nutrition analysis program available in the library to further evaluate their findings, and nine cited specific references. On average, each student provided their client with 5 recommendations, the majority of which were judged by the nutrition faculty member to be appropriate and practical. The overall quality of the completed assignments indicates that early involvement of medical students may enhance their interest in nutrition and secondarily reach community preceptors with information about new nutrition applications.

Relationships of Record Keeping, Levels of Reported Physical Activity and Body Composition with Weight Loss

Abstract Physical activity has been indicated for the reduction of body fat mass but its association with preservation of lean body mass has not been thoroughly examined. Thus, this study examined the relationships of different levels of physical activity measured by an activity monitor which counted steps (digiwalker) with record keeping on a monthly log and lean body mass (fat free mass and body cell mass) obtained by bioelectrical impedance. To study whether recording physical activity on the monthly record was associated with increased weight loss, data on 61 women (BMI 25 to 35; ages 30 to 50) currently participating in a one-year weight loss study were analyzed. A total of 42/61 (69%) of these women were classified as compliant (digiwalker recordings of ≥ 25%) and 19/61 (31%) were classified as non-compliant. Overall, the compliant women had lost an average of 2.5 Ibs. of fat (p=.037) determined by bioimpedance and 4.5 pounds (p=.033) in total weight more than the non-compliant women. Further, data from the 36/42 (86%) compliant women on whom complete data for a 21-week period were available were analyzed for relationships with body composition. Reported physical activity (digiwalker readings) on the monthly records were categorized into low, medium, or high levels based on the population studied ( 10,000 steps/day, respectively). The average weight loss at the end of the 21-week period was 8.5 ± 7.2 Ibs. Women who had reported low activity tended to significantly (p=.090) lose more fat free mass (−2.0 ± 1.5 Ibs.) than those reporting both medium and high activity levels (−3.0 ±1.5 Ibs.) and although body cell mass also tended to decrease more in those with low activity, these findings were not significant at the one-tail level. This study indicates that moderate to high levels of physical activity was related to preservation of lean body mass and is an important factor to consider when trying to lose weight. Additionally, record keeping was assumably related to level of physical activity and increased not only total weight loss, but also loss of fat mass and was shown to be a valuable tool in successful weight loss efforts.