GnRH molecular variants in the brain and pituitary gland of pejerrey, Odontesthes bonariensis (Atheriniformes). Immunological and chromatographic evidence for the presence of a novel molecular variant

Gonadotropin-releasing hormone (GnRH) molecular variants in the brain and pituitary gland of pejerrey, Odontesthes bonariensis (Atheriniformes), were characterized by gradient reverse phase high performance liquid chromatography (RP-HPLC). Eluted fractions were tested in radioimmunoassays with different antisera. The results show that the brain extract contains three forms of GnRH: one is immunologically and chromatographically similar to cIIGnRH (chicken II), and another is similar to sGnRH (salmon). A third GnRH appears to be chromatographic and immunologically different from the nine other known forms of the vertebrate hormone. This is the only variant present in the pituitary gland.     

Classification of the effectiveness of combination treatments

According to FDA regulations, a combination drug is not efficacious unless each component contributes to the claimed effects. For a univariate endpoint, this implies that the combination at specific doses must be superior to each of its components at the same doses. More demanding is the property of synergy, in which the effect of the combination must be superior to the effect expected based on those of its components. If it is equal to those effects, it is additive, and if it is inferior, it is antagonistic. We give regions in the combination dose plane where these concepts are well defined. If the effect of the combination is greater than the greatest effect achievable by any of its components it is therapeutically synergistic. A combination can be antagonistic, yet its components can still contribute to the claimed effects. If it is additive, synergistic or therapeutically synergistic, its components must contribute to the claimed effects. We relate these concepts and provide designs and sequential procedures for determining whether a combination is therapeutically synergistic, synergistic, additive, antagonistic and contributing or antagonistic and non-contributing.     

A strategy for improving patient satisfaction by the intensive training of residents in psychosocial medicine: a controlled, randomized study

PURPOSE: To use a controlled, randomized design to assess the effect on patient satisfaction of an intensive psychosocial training program for residents. METHOD: Twenty-six first-year residents, in two internal medicine and family practice community-based programs affiliated with the Michigan State University College of Human Medicine, were randomly assigned during 1991 and 1992 to a control group or a one-month intensive training program. Experiential teaching focused on many psychosocial skills required in primary care. A 29-item questionnaire administered before and after the residents' training evaluated their patients' satisfaction regarding patient disclosure, physician empathy, confidence in physician, general satisfaction, and comparison of the physician with other physicians. Analyses of covariance with groups and gender as factors and pre-training patient satisfaction scores as the covariate evaluated the effect of the training. RESULTS: The patients of the trained residents expressed more confidence in their physicians (p = .01) and more general satisfaction (p = .02) than did the patients of controls. The effect of training on patient satisfaction with patient disclosure (p < .01) and physician empathy (p < .05) was greater for female than for male residents. CONCLUSION: The intensive psychosocial training program for residents improved their patients' satisfaction.     

Demonstration of Epstein-Barr viral DNA in paraffin-embedded tissues of Burkitt's lymphoma from Argentina using the polymerase chain reaction and in situ hybridization

Burkitt's lymphoma (BL) is the most frequent non-Hodgkin's lymphoma in children in Argentina. Although epidemiologic studies have linked Epstein-Barr virus (EBV) to more than 90% of African BL cases but to only 10-20% of American and French cases, increased EBV-specific antibody titers were demonstrated in 73% of Argentinian patients with BL. To characterize the relationship between EBV and BL in Argentina, we analyzed paraffin-embedded tissues from 16 cases of BL for the presence of EBV DNA using the polymerase chain reaction (PCR) and in situ hybridization (ISH). PCR analysis showed that only 4 of 16 specimens contained the EBV BamW fragment, and these specimens were all from cases diagnosed in 1984. Results of ISH performed with a specific biotinylated DNA probe against the NotI/PstI fragment of EBV correlated with the PCR findings. EBV sequences were detected with ISH in 70-90% of the tumor cells from the 4 positive cases. These data may suggest an epidemic outbreak of EBV-related BL in 1984 superimposed on sporadic cases of BL, for which EBV may not have been an essential factor. This study also demonstrates the value of using molecular techniques on archival tissue to track epidemiologic trends.     

Learning navigational maps through potentiation and modulation of hippocampal place cells

We analyze a model of navigational map formation based on correlation-based, temporally asymmetric potentiation and depression of synapses between hippocampal place cells. We show that synaptic modification during random exploration of an environment shifts the location encoded by place cell activity in such a way that it indicates the direction from any location to a fixed target avoiding walls and other obstacles. Multiple maps to different targets can be simultaneously stored if we introduce target-dependent modulation of place cell activity. Once maps to a number of target locations in a given environment have been stored, novel maps to previously unknown target locations are automatically constructed by interpolation between existing maps.     

Improving outcomes using dental implants: integrating improvements in clinical practice

Modern restorative dentistry is confronted with many challenges related to implant use in the craniofacial region, such as attempting to place implants in esthetically critical sites or anatomically limiting regions of the jaw. To assure a successful implant placement that is satisfactory to both the patient and the dentist, four key areas need to be improved: diagnostic procedures, surgical procedures and outcomes, esthetic results, and prosthetic complications. This article discusses how an integrated approach to these areas can improve clinical practice.