hypermutation, suggesting that cis-acting sequences outside the mutable region regulate and target mutation. However, almost nothing is known about the detailed molecular mechanisms or transacting proteins that are responsible for V-region hypermutation. Because the mutational process begins just downstream of the promoter and requires transcriptional en-hancers (Neuberger et al., 1998), it has...

OBJECTIVES Psychobiological sensitization and health worry appear to be involved in the etiology of clinical manifestations of subjective health complaints (SHCs) via amplified processing of health-related information. However, it is not clear whether sensitization and health worry are also associated with common SHCs, which are extremely prevalent and are responsible for a large part of both h...

Little is known about spinal visceral reflexes in brain-dead man, although they have been described in experimental animals. In 1983, 25 brain-dead individuals were observed during donor nephrectomy. It was confirmed that some of these donors, without higher centre modulation and not under significant pharmacological influence, had viscero-somatic motor reflexes and viscero-visceral cardiovascu...

We previously described T15H chain mutants that were impaired in assembly with L chain and in ability to be secreted from the cell. The unmutated T15L chain is unusual in that it is secretion-impaired in the absence of assembly with H chain. The T15L chain preferentially pairs with T15H in vivo, suggesting that if we introduced mutations that would allow secretion of free T15L chain, they might...

Recent modeling of spike-timing-dependent plasticity indicates that plasticity involves as a third factor a local dendritic potential, besides pre- and postsynaptic firing times. We present a simple compartmental neuron model together with a non-Hebbian, biologically plausible learning rule for dendritic synapses where plasticity is modulated by these three factors. In functional terms, the rul...

Somatic hypermutation (SHM) introduces nucleotide substitutions into immunoglobulin variable (Ig V) region genes at all four bases, but the mutations at C/G and A/T pairs are achieved by distinct mechanisms. Mutations at C/G pairs are a direct consequence of the C-->U deamination catalyzed by activation-induced deaminase (AID). Mutations at A/T pairs, however, require a second mutagenic process...

Understanding the fate of enteric viruses in water is vital for protection of water quality. However, the decay of enteric viruses is not well characterized, and its uncertainty has not been examined yet. In this study, the decay of coliphages, an indicator for enteric viruses, was investigated in situ under both sunlit and shaded conditions as well as in summer and winter. The decay rates of c...