Neuropeptide interactions and REM sleep: a role for Urotensin II?

Urotensin II (UII) is a peptide with structural similarity to the somatostatin family with potent vasoconstrictor activity. UII receptor is expressed broadly in the periphery, and most notably in the heart and microvessels. In the brain, the UII receptor can be detected in the spinal cord and in cholinergic nuclei in the brainstem known to be involved in REM sleep regulation. Recent data suggest that, in addition to their vasoactive properties, UII receptor ligands may have excitatory activity on a selective group of neurons that modulate REM sleep. This review focuses on the implications of these findings for the neurobiology of REM sleep regulation and discusses the possible impact of UII and other neuropeptides on the balance of the alternation between sleep states.     

Type II diabetes of early onset: a distinct clinical and genetic syndrome?

The inheritance of non-insulin-dependent (type II) diabetes was studied by a continuous infusion of glucose test in all available first degree relatives of 48 diabetic probands of various ages and with differing severity of disease. In an initial study of 38 type II diabetic subjects and their first degree relatives six islet cell antibody negative patients with early onset disease (aged 25-40 at diagnosis) were found to have a particularly high familial prevalence of diabetes or glucose intolerance. Nine of 10 parents available for study either had type II diabetes or were glucose intolerant. A high prevalence of diabetes or glucose intolerance was also found in their siblings (11/16;69%). In a second study of the families of a further 10 young diabetic probands (presenting age 25-40) whose islet cell antibody state was unknown a similar high prevalence of diabetes or glucose intolerance was found among parents of the five islet cell antibody negative probands (8/9; 89%) but not among parents of the five islet cell antibody positive probands (3/8;38%). Islet cell antibody negative diabetics with early onset type II disease may have inherited a diabetogenic gene or genes from both parents. They commonly need insulin to maintain adequate glycaemic control and may develop severe diabetic complications. Early onset type II diabetes may represent a syndrome in which characteristic pedigrees, clinical severity, and absence of islet autoimmunity make it distinct from either type I diabetes, maturity onset diabetes of the young, or late onset type II diabetes.     

Simultaneous open rhinoplasty and alar base excision: is there a problem with the blood supply of the nasal tip and columellar skin?

In a prospective study, 15 consecutive patients who underwent simultaneous open rhinoplasty and alar base excision were included to investigate whether there is a problem with the blood supply of the nasal tip and columellar skin. During the surgical procedure in these patients, there was transection of the columellar arteries and external nasal arteries, and frequently of the alar branches of the angular artery. Yet, none of the patients had any evidence of ischemia of the nasal tip or columellar skin, and there was primary wound healing with a thin-line transcolumellar scar in all patients. Techniques to avoid injury to the lateral nasal artery and nasal tip plexus are discussed. It was concluded that simultaneous open rhinoplasty and alar base excision is safe as long as certain surgical principles are applied.     

MicroRNA and brain tumors: a cause and a cure?

Malignant brain tumors, including high-grade gliomas, are among the most lethal of all cancers. Despite considerable advances, including multi-modal treatments with surgery, radiotherapy, and chemotherapy, the overall prognosis remains dismal for patients diagnosed with these tumors. With the discovery of RNA interference (RNAi) for target-specific gene silencing via small interfering RNA (siRNA), a novel method to target malignant gliomas has been exposed, an endeavor that is aggressively being carried out in numerous laboratories. However, practical difficulties in tissue- or organ-specific targeting of therapeutic quantities of siRNA still preclude its applicability in a clinical setting. MicroRNA (miRNA), an endogenously expressed form of siRNA, not only presents an alternate method to induce RNAi in a given diseased tissue or organ, but also exposes a unique set of diagnostic markers that can be used to identify, and then differentiate between tumor grades. Thus, miRNA can be considered the cells' answer to siRNA. Discovered over a decade ago, miRNA is fast becoming recognized as crucial in regulating gene expression in cancers. Therein lies the therapeutic potential of miRNA, as it may now be possible to induce or inhibit RNAi in a given diseased cell population by controlling the cells' miRNA expression profile. This review outlines the potential of miRNA as a therapeutic strategy against high-grade gliomas, and also the technological hurdles that need to be addressed before this promising technique can be administered in a clinical setting.     

Microalgae and biofuels: a promising partnership?

Microalgae have much higher lipid yields than those of agricultural oleaginosous crops, and they do not compromise arable land. Despite this, current microalga-based processes suffer from several constraints pertaining to the biocatalyst and the bioreactor, which hamper technologically and economically feasible scale-up. Here, we briefly review recent active research and development efforts worldwide, and discuss the most relevant shortcomings of microalgal biofuels. This review goes one step further relative to related studies, because it tackles otherwise scarcely mentioned issues - for example, heterotrophic versus autotrophic metabolism, alkane versus glyceride synthesis, conduction versus bubbling of CO(2), and excretion versus accumulation of lipids. Besides promising solutions that have been hypothesized and arise from multidisciplinary approaches, we also consider less conventional ones. Microalgae and biofuels hold indeed a promising partnership, but a fully competitive technology is not expected to be available before the end of this decade, because the need for one order of magnitude increase in productivity requires development of novel apparatuses and transformed cells.     

Myopia and intelligence:a pleiotropic relationship?

Summary The well-established association between myopia and superior intelligence in the general population was investigated in a group of intellectually gifted children and their less gifted full siblings to determine whether the relationship of myopia to psychometric intelligence is consistent with the hypothesis of pleiotropy, i.e., both characteristics are affected by the same gene or set of genes. Failure to find a difference in degree of myopia, assessed as a metric variable, between intellectually gifted and nongifted siblings would contradict pleiotropy. A variety of possible causal pathways, both genetic and environmental, have been hypothesized in the literature to explain the relationship between intelligence and myopia, and these still cannot be ruled out. It is theoretically noteworthy, however, in view of the independent evidence for the considerable heritability of both intelligence and myopia, that the highly significant gifted-nongifted sibling difference in myopia found in the present study is consistent with the hypothesis that intelligence and myopia are related pleiotropically.     

Hybrid speciation in sparrows II: a role for sex chromosomes?

Homoploid hybrid speciation in animals is poorly understood, mainly because of the scarcity of well‐documented cases. Here, we present the results of a multilocus sequence analysis on the house sparrow (Passer domesticus), Spanish sparrow (P. hispaniolensis) and their proposed hybrid descendant, the Italian sparrow (P. italiae). The Italian sparrow is shown to be genetically intermediate between the house sparrow and Spanish sparrow, exhibiting genealogical discordance and a mosaic pattern of alleles derived from either of the putative parental species. The average variation on the Z chromosome was significantly reduced compared with autosomal variation in the putative parental species, the house sparrow and Spanish sparrow. Additionally, divergence between the two species was elevated on the Z chromosome relative to the autosomes. This pattern of variation and divergence is consistent with reduced introgression of Z‐linked genes and/or a faster‐Z effect (increased rate of adaptive divergence on the Z). F_ST‐outlier tests were consistent with the faster‐Z hypothesis: two of five Z‐linked loci (CHD1Z and PLAA) were identified as candidates for being subject to positive, divergent selection in the putative parental species. Interestingly, the two latter genes showed a mosaic pattern in the (hybrid) Italian sparrow; that is, the Italian sparrow was found to be fixed for Spanish sparrow alleles at CHD1Z and to mainly have house sparrow alleles at PLAA. Preliminary evidence presented in this study thus suggests that sex chromosomes may play a significant role in this case of homoploid hybrid speciation.     

Endonuclease II of coliphage T4: a recombinase disguised as a restriction endonuclease?

EndoII shares with restriction endonucleases the property of cleaving foreign DNA while leaving the endonuclease-encoding genome intact, ensuring the survival of one DNA species in the cell. In addition, in vivo EndoII cleaves a specific DNA sequence and cleavage is context dependent. These context effects extend over at least 1000 bp, largely limiting cleavage to once within this distance. Like homing endonucleases, in vivo EndoII recognizes a long, asymmetric and degenerate consensus sequence which has two distinct parts. Recognition of one part of the consensus sequence involves base-specific bonds, and recognition of the other involves sequence-dependent helical structure. EndoII fulfils an obvious short-term survival role in ensuring the dominance of phage DNA in an infected cell, but may also have a long-term evolutionary role, producing gene-size fragments of foreign DNA to be enrolled in the phage genetic repertoire.     

ROCs and SOCs: what's in a name?

There is currently a great deal of interest in the relative contributions of external and internally sequestered Ca(2+) in various physiological responses. However, this field is losing clarity due to inattentive use of terms. In particular, the terms "receptor-operated channels" and "store-operated channels" (ROCs and SOCs, respectively) are becoming ambiguous through over-use. In this paper, we will first consider basic principles of channel gating in order to set the stage for defining criteria which can be used to distinguish precisely between different channel-related functions. We will then focus on recurring examples of adventurous use of terminology, or of blurring of the distinctions between channel types, and propose solutions to this quandary.     

Proteolysis and cell migration: creating a path?

Both serine and metalloproteinases have been implicated in the complex integrated events underlying cell migration but no definitive single mechanism has emerged. Work over the past two years linking both membrane and soluble proteinases with integrins and other adhesion proteins and with intracellular signalling systems could herald the beginnings of a potential expansion of our understanding of the role and regulation of proteolysis in cell migration.