Selective release of glutamate from cerebellar granule cells differentiating in culture

The aim of the present study was to assess whether endogenous and newly synthesized glutamate can be released from differentiating cultured cerebellar granule cells in a way compatible with a neurotransmitter role. Granule cells from 8-day-old rat cerebella were grown in basal Eagle's medium with 10% fetal calf serum for 2-12 days in vitro (DIV), then washed with Krebs-Ringer medium, and labeled for 45 min with tracer amounts of radioactive glutamine. Subsequently, the release of endogenous glutamate and of newly formed radioactive glutamate was measured in basal conditions and upon depolarization with elevated K⁺ concentration or veratridine. At 2 DIV, the release of endogenous and newly synthesized glutamate evoked by high K⁺ concentration was small and Ca²⁺ independent, but it progressively and steadily increased (up to 8- to 10-fold) and became Ca²⁺ dependent (up to 80-85%) at later stages (4, 8, and 12 DIV). Veratridine was almost ineffective with cells at 2 DIV but greatly increased glutamate release (endogenous and neosynthesized) at 8 DIV, and its action was totally antagonized by tetrodotoxin. The level and synthesis of glutamate remained fairly constant in cells from 2 to 12 DIV. γ-Aminobutyric acid synthesis from radioactive glutamine was about 3% of that of glutamate, and γ-aminobutyric acid release (endogenous and neosynthesized) was not measurable. Aspartate synthesis was about 10% of that of glutamate, and the high K⁺ concentration-evoked release of this amino acid was modest and scarcely affected by Ca²⁺. Neither high K⁺ concentration nor veratridine was able to induce glutamate release from confluent cerebellar astrocyte cultures at 14 DIV, although the level and synthesis of the amino acid were comparable to those in granule cells. In conclusion, the data show that a stimulus-coupled release of endogenous and neosynthesized glutamate is progressively expressed by cerebellar granule cells differentiating in culture, and this strongly supports the concept that glutamate is the neurotransmitter of these cells.     

Human herpesvirus 7 is a T-lymphotropic virus and is related to, but significantly different from, human herpesvirus 6 and human cytomegalovirus.

An independent strain (JI) of human herpesvirus 7 (HHV-7) was isolated from a patient with chronic fatigue syndrome (CFS). No significant association could be established by seroepidemiology between HHV-7 and CFS. HHV-7 is a T-lymphotropic virus, infecting CD4+ and CD8+ primary lymphocytes. HHV-7 can also infect SUP-T1, an immature T-cell line, with variable success. Southern blot analysis with DNA probes scanning 58.8% of the human herpesvirus 6 (HHV-6) genome and hybridizing to all HHV-6 strains tested so far revealed homology to HHV-7 with only 37.4% of the total probe length. HHV-7 contains the GGGTTA repetitive sequence, as do HHV-6 and Marek's disease chicken herpesvirus. DNA sequencing of a 186-base-pair fragment of HHV-7(JI) revealed an identity with HHV-6 and human cytomegalovirus of 57.5% and 36%, respectively. Oligonucleotide primers derived from this sequence (HV7/HV8, HV10/HV11) amplified HHV-7 DNA only and did not amplify DNA from other human herpesviruses, including 12 different HHV-6 strains. Southern blot analysis with the p43L3 probe containing the 186-base-pair HHV-7 DNA fragment hybridized to HHV-7 DNA only. The molecular divergence between human cytomegalovirus, on the one hand, and HHV-6 and HHV-7, on the other, is greater than between HHV-6 and HHV-7, which, in turn, is greater than the difference between HHV-6 strains. This study supports the classification of HHV-7 as an additional member of the human beta-herpesviruses.     

Implementing Community-Based Diabetes Programs: The Scripps Whittier Diabetes Institute Experience

Diabetes affects a large and growing segment of the US population. Ethnic and racial minorities are at disproportionate risk for diabetes, with Hispanics and non-Hispanic Blacks showing a near doubling of risk relative to non-Hispanic Whites. There is an urgent need to identify low cost, effective, and easily implementable primary and secondary prevention approaches, as well as tertiary strategies that delay disease progression, complications, and associated deterioration in function in patients with diabetes. The Chronic Care Model provides a well-accepted framework for improving diabetes and chronic disease care in the community and primary care medical home. A number of community-based diabetes programs have incorporated this model into their infrastructure. Diabetes programs must offer accessible information and support throughout the community and must be delivered in a format that is understood, regardless of literacy and socioeconomic status. This article will discuss several successful, culturally competent community-based programs and the key elements needed to implement the programs at a community or health system level. Health systems together with local communities can integrate the elements of community-based programs that are effective across the continuum of the care to enhance patient-centered outcomes, enable patient acceptability and ultimately lead to improved patient engagement and satisfaction.