Conservation of position and exclusive expression of mouse Xist from the inactive X chromosome

X-chromosome inactivation in mammals is a regulatory phenomenon whereby one of the two X chromosomes in female cells is genetically inactivated, resulting in dosage compensation for X-linked genes between males and females. In both man and mouse, X-chromosome inactivation is thought to proceed from a single cis-acting switch region or inactivation centre (XIC/Xic). In the human, XIC has been mapped to band Xq13 (ref. 6) and in the mouse to band XD (ref. 7), and comparative mapping has shown that the XIC regions in the two species are syntenic. The recently described human XIST gene maps to the XIC region and seems to be expressed only from the inactive X chromosome. We report here that the mouse Xist gene maps to the Xic region of the mouse X chromosome and, using an interspecific Mus spretus/Mus musculus domesticus F1 hybrid mouse carrying the T(X;16)16H translocation, show that Xist is exclusively expressed from the inactive X chromosome. Conservation between man and mouse of chromosomal position and unique expression exclusively from the inactive X chromosome lends support to the hypothesis that XIST and its mouse homologue are involved in X-chromosome inactivation.

The E6 protein of human papillomavirus type 16 binds to and inhibits co-activation by CBP and p300

The co-activators CBP and p300 are important for normal cell differentiation and cell cycle progression and are the targets for viral proteins that dysregulate these cellular processes. We show here that the E6 protein from the oncogenic human papillomavirus type 16 (HPV-16) binds to three regions (C/H1, C/H3 and the C-terminus) of both CBP and p300. The interaction of E6 with CBP/p300 was direct and independent of proteins known to bind the co-activators, such as p53. The E6 protein from low-risk HPV type 6 did not interact with C/H3 or the C-terminus but associated with the C/H1 domain at 50% of the level of HPV-16. HPV-16 E6 inhibited the intrinsic transcriptional activity of CBP/p300 and decreased the ability of p300 to activate p53- and NF-kappaB-responsive promoter elements. Interestingly, some mutations in HPV-16 E6 abrogated C/H3-E6 interactions, but did not alter the ability of E6 to associate with the C/H1 domain, suggesting that these modified proteins could be used to delineate the functional significance of the C/H1 and C/H3 domains of CBP/p300.

Expression of Xist during mouse development suggests a role in the initiation of X chromosome inactivation

The mouse Xist gene maps to the X inactivation center (Xic) region and is expressed exclusively from the inactive X chromosome. It is thus a candidate gene for the Xic. We show that the onset of Xist expression in mouse development precedes X chromosome inactivation and may therefore be a cause rather than merely a consequence of X inactivation. The earliest Xist expression in morulae and blastocysts is imprinted, resulting in specific expression of the paternal Xist allele. Imprinted Xist expression may thus be the cause of nonrandom inactivation of the paternal X in trophectoderm. Strong Xce alleles can act to reduce the effect of imprinted Xist expression in the trophectoderm. The imprint on Xist expression is lost shortly before gastrulation when random X inactivation occurs. Our data support a direct role for Xist in the initiation of X inactivation.

Connexin30 in rodent, cat and human brain: selective expression in gray matter astrocytes, co-localization with connexin43 at gap junctions and late developmental appearance

We previously presented evidence [Nagy et al. (1997) Neuroscience 78, 533-548] that, in addition to their ubiquitous expression of connexin43, astrocytes produce a second connexin suggested to be connexin30, a recently discovered member of the family of gap junction proteins. A connexin30 specific antibody was subsequently developed and utilized here to confirm and extend our earlier observations. On western blots, this antibody detected a 30,000 mol. wt protein in rat, mouse, cat and human brain, and exhibited no cross-reaction with connexin43, connexin26 or any other known connexins expressed in brain. Immunohistochemically, connexin30 was localized in astrocytes, at gap junctions between these cells and on the astrocyte side of gap junctions between astrocytes and oligodendrocytes. Double labelling revealed co-localization of connexin30 and connexin43 at astrocytic gap junctions. Punctate immunolabelling patterns for both connexins were qualitatively similar, but differences were evident. In contrast to regional connexin43 expression, diencephalic and hindbrain areas exhibited considerably greater expression than forebrain areas, subcortical perivascular astrocytic endfeet were more heavily labelled for connexin30, white matter tracts such as corpus callosum, internal capsule and anterior commissure were devoid of connexin30, and appreciable levels of connexin30 during development were not seen until about postnatal day 15. These results indicate that connexin30 is expressed by gray, but not white matter astrocytes, its distribution is highly heterogeneous in gray matter, it is co-localized with connexin43 at astrocytic gap junctions where it forms homotypic or heterotypic junctions, and its emergence is delayed until relatively late during brain maturation. Taken together, these results suggest that astrocytic connexin30 expression at both regional and cellular levels is subject to regulation in adult brain as well as during brain development.

Immunogold evidence that neuronal gap junctions in adult rat brain and spinal cord contain connexin-36 but not connexin-32 or connexin-43

Physiological and ultrastructural evidence indicates that gap junctions link many classes of neurons in mammalian central nervous system (CNS), allowing direct electrical and metabolic communication. Among at least six gap junction-forming connexin proteins in adult rat brain, connexin- (Cx) 32, Cx36, and Cx43 have been reported to occur in neurons. However, no connexin has been documented at ultrastructurally defined neuronal gap junctions. To address this question directly, freeze-fracture replica immunogold labeling (FRIL) and immunofluorescence (IF) were used to visualize the subcellular and regional localization of Cx36 in rat brain and spinal cord. Three antibodies were generated against different sequences in Cx36. By Western blotting, these antibodies detected protein at 36 and 66 kDa, corresponding to Cx36 monomer and dimer forms, respectively. After double-labeling for Cx36 and Cx43 by FRIL, neuronal gap junctions in inferior olive, spinal cord, and retina were consistently immunogold-labeled for Cx36, but none were labeled for Cx43. Conversely, Cx43 but not Cx36 was detected in astrocyte and ependymocyte gap junctions. In >250 Cx32/Cx43 single- and double-labeled replicas from 10 CNS regions, no neuronal gap junctions were labeled for either Cx32 or Cx43. Instead, Cx32 and Cx43 were restricted to glial gap junctions. By IF, Cx36 labeling was widely distributed in neuropil, including along dendritic processes and within neuronal somata. On the basis of FRIL identification of Cx36 in neuronal gap junctions and IF imaging of Cx36 throughout rat brain and spinal cord, neuronal gap junctions containing Cx36 appear to occur in sufficient density to provide widespread electrical and metabolic coupling in adult CNS.

Functional analysis of bone morphogenetic protein type II receptor mutations underlying primary pulmonary hypertension

A wide range of mutations in the type II receptor for bone morphogenetic protein (BMPR-II) have been shown to underlie primary pulmonary hypertension. To determine the mechanism of altered BMPR-II function, we employed transient transfection studies in cell lines and primary cultures of pulmonary vascular smooth muscle cells using green fluorescent protein (GFP)-tagged wild-type and mutant BMPR2 constructs and confocal microscopy to localize receptors. Substitution of cysteine residues in the ligand binding or kinase domain prevented trafficking of BMPR-II to the cell surface, and reduced binding of (125)I-BMP4. In addition, transfection of cysteine-substituted BMPR-II markedly reduced basal and BMP4-stimulated transcriptional activity of a BMP/Smad responsive luciferase reporter gene (3GC2wt-Lux), compared with wild-type BMPR-II, suggesting a dominant-negative effect of these mutants on Smad signalling. In contrast, BMPR-II containing non-cysteine substitutions in the kinase domain were localized to the cell membrane, although these also suppressed the activity of 3GC2wt-Lux. Interestingly, BMPR-II mutations within the cytoplasmic tail trafficked to the cell surface, but retained the ability to activate 3GC2wt-Lux. Transfection of mutant, but not wild-type, constructs into a mouse epithelial cell line (NMuMG cells) led to activation of p38(MAPK) and increased serum-induced proliferation compared with the wild-type receptor, which was partly p38(MAPK)-dependent. We conclude that mutations in BMPR-II heterogeneously inhibit BMP/Smad-mediated signalling by diverse molecular mechanisms. However, all mutants studied demonstrate a gain of function involving upregulation of p38(MAPK)-dependent proproliferative pathways.

Stronger inflammatory/cytotoxic T-cell response in women identified by microarray analysis

Women develop chronic inflammatory autoimmune diseases more often than men. The mechanisms causing the increased susceptibility are incompletely understood. Chronic immune stimulation characterizes many autoimmune disorders. We hypothesized that repeated stimulation may cause a different T cell response in women than men. Microarrays were used to compare gene expression in T cells from healthy men and women with and without repeated stimulation. Four days following a single stimulation only 25% of differentially expressed, gender-biased genes were expressed at higher levels in women. In contrast, following restimulation 72% were more highly expressed in women. Immune response genes were significantly over-represented among the genes upregulated in women and among the immune response genes, the inflammatory/cytotoxic effector genes interferon gamma (IFNG), lymphotoxin beta (LTB), granzyme A (GZMA), interleukin-12 receptor beta2 (IL12RB2), and granulysin (GNLY) were among those overexpressed to the greatest degree. In contrast, IL17A was the only effector gene more highly expressed in men. Estrogen response elements were identified in the promoters of half the overexpressed immune genes in women, and in <10% of the male biased genes. The differential expression of inflammatory/cytotoxic effector molecules in restimulated female T cells may contribute to the differences in autoimmune diseases between women and men.

Early and longitudinal evaluations of treated infants and children and untreated historical patients with congenital toxoplasmosis: the Chicago Collaborative Treatment Trial

Between December 1981 and May 1991, 44 infants and children with congenital toxoplasmosis were referred to our study group. A uniform approach to evaluation and therapy was developed and is described herein along with the clinical characteristics of these infants and children. In addition, case histories that illustrate especially important clinical features or previously undescribed findings are presented. Factors that contributed to the more severe disabilities included delayed diagnosis and initiation of therapy; prolonged, concomitant neonatal hypoxia and hypoglycemia; profound visual impairment; and prolonged, uncorrected increased intracranial pressure with hydrocephalus and compression of the brain. Years after therapy was discontinued, three children developed new retinal lesions (without loss of visual acuity when therapy for Toxoplasma gondii was initiated promptly), and three children experienced a new onset of afebrile seizures. Most remarkable were the normal developmental, neurological, and ophthalmologic findings at the early follow-up evaluations of many--but not all--of the treated children despite severe manifestations, such as substantial systemic disease, hydrocephalus, microcephalus, multiple intracranial calcifications, and extensive macular destruction detected at birth. These favorable outcomes contrast markedly with outcomes reported previously for children with congenital toxoplasmosis who were untreated or treated for only 1 month.

Risk factors and opportunities for prevention of early-onset neonatal sepsis: a multicenter case-control study

BACKGROUND

Early-onset group B streptococcal (GBS) prevention efforts are based on targeted use of intrapartum antibiotic prophylaxis (IAP); applicability of these prevention efforts to infections caused by other organisms is not clear.

METHODS

Multicenter surveillance during 1995 to 1996 for culture-confirmed, early-onset sepsis in an aggregate of 52 406 births; matched case-control study of risk factors for GBS and other sepsis.

RESULTS

Early-onset disease occurred in 188 infants (3.5 cases per 1000 live births). GBS (1.4 cases per 1000 births) and Escherichia coli (0.6 cases per 1000 births) caused most infections. GBS sepsis less often occurred in preterm deliveries compared with other sepsis. Compared with gestation-matched controls without documented sepsis, GBS disease was associated with intrapartum fever (matched OR, 4.1; CI, 1.2-13.4) and frequent vaginal exams (matched OR, 2.9; CI, 1.1-8. 0). An obstetric risk factor-preterm delivery, intrapartum fever, or membrane rupture >/=18 hours-was found in 49% of GBS cases and 79% of other sepsis. IAP had an adjusted efficacy of 68.2% against any early-onset sepsis. Ampicillin resistance was evident in 69% of E coli infections. No deaths occurred among susceptible E coli infections, whereas 41% of ampicillin-resistant E coli infections were fatal. Ninety-one percent of infants who developed ampicillin-resistant E coli infections were preterm, and 59% of these infants were born to mothers who had received IAP.

CONCLUSIONS

Either prenatal GBS screening or a risk-based strategy could potentially prevent a substantial portion of GBS cases. Sepsis caused by other organisms is more often a disease of prematurity. IAP seemed efficacious against early-onset sepsis. However, the severity of ampicillin-resistant E coli sepsis and its occurrence after maternal antibiotics suggest caution regarding use of ampicillin instead of penicillin for GBS prophylaxis.

Evidence that random and imprinted Xist expression is controlled by preemptive methylation

The mouse Xist gene is expressed exclusively from the inactive X chromosome and may control the initiation of X inactivation. We show that in somatic tissues the 5' end of the silent Xist allele on the active X chromosome is fully methylated, while the expressed allele on the inactive X is completely unmethylated. In tissues that undergo imprinted paternal Xist expression and imprinted X inactivation, the paternal Xist allele is unmethylated, and the silent maternal allele is fully methylated. In the male germline, a developmentally regulated demethylation of Xist occurs at the onset of meiosis and is retained in mature spermatozoa. This may be the cause of imprinted expression of the paternal Xist allele. A role for methylation in the control of Xist expression is further supported by the finding that in differentiating embryonic stem cells during the initiation of X inactivation, differential methylation of Xist alleles precedes the onset of Xist expression.

NMR studies of DNA (R+)n.(Y-)n.(Y+)n triple helices in solution: imino and amino proton markers of T.A.T and C.G.C+ base-triple formation

High-resolution exchangeable proton two-dimensional NMR spectra have been recorded on 11-mer DNA triple helices containing one oligopurine (R)n and two oligopyrimidine (Y)n strands at acidic pH and elevated temperatures. Our two-dimensional nuclear Overhauser effect studies have focused on an 11-mer triplex where the third oligopyrimidine strand is parallel to the oligopurine strand. The observed distance connectivities establish that the third oligopyrimidine strand resides in the major groove with the triplex stabilized through formation of T.A.T and C.G.C+ base triples. The T.A.T base triple can be monitored by imino protons of the thymidines involved in Watson-Crick (13.65-14.25 ppm) and Hoogsteen (12.9-13.55 ppm) pairing, as well as the amino protons of adenosine (7.4-7.7 ppm). The amino protons of the protonated (8.5-10.0 ppm) and unprotonated (6.5-8.3 ppm) cytidines in the C.G.C+ base triple provide distinct markers as do the imino protons of the guanosine (12.6-13.3 ppm) and the protonated cytidine (14.5-16.0 ppm). The upfield chemical shift of the adenosine H8 protons (7.1-7.3 ppm) establishes that the oligopurine strand adopts an A-helical base stacking conformation in the 11-mer triplex. These results demonstrate that oligonucleotide triple helices can be readily monitored by NMR at the individual base-triple level with distinct markers differentiating between Watson-Crick and Hoogsteen pairing. Excellent exchangeable proton spectra have also been recorded for (R+)n.(Y-)n.(Y+)n 7-mer triple helices with the shorter length permitting spectra to be recorded at ambient temperature.(ABSTRACT TRUNCATED AT 250 WORDS)

Connexin26 in adult rodent central nervous system: demonstration at astrocytic gap junctions and colocalization with connexin30 and connexin43

The connexin family of proteins (Cx) that form intercellular gap junctions in vertebrates is well represented in the mammalian central nervous system. Among these, Cx30 and Cx43 are present in gap junctions of astrocytes. Cx32 is expressed by oligodendrocytes and is present in heterologous gap junctions between oligodendrocytes and astrocytes as well as at autologous gap junctions between successive myelin layers. Cx36 mRNA has been identified in neurons, and Cx36 protein has been localized at ultrastructurally defined interneuronal gap junctions. Cx26 is also expressed in the CNS, primarily in the leptomeningeal linings, but is also reported in astrocytes and in neurons of developing brain and spinal cord. To establish further the regional, cellular, and subcellular localization of Cx26 in neural tissue, we investigated this connexin in adult mouse brain and in rat brain and spinal cord using biochemical and immunocytochemical methods. Northern blotting, western blotting, and immunofluorescence studies indicated widespread and heterogeneous Cx26 expression in numerous subcortical areas of both species. By confocal microscopy, Cx26 was colocalized with both Cx30 and Cx43 in leptomeninges as well as along blood vessels in cortical and subcortical structures. It was also localized at the surface of oligodendrocyte cell bodies, where it was coassociated with Cx32. Freeze-fracture replica immunogold labeling (FRIL) demonstrated Cx26 in most gap junctions between cells of the pia mater by postnatal day 4. By postnatal day 18 and thereafter, Cx26 was present at gap junctions between astrocytes and in the astrocyte side of most gap junctions between astrocytes and oligodendrocytes. In perinatal spinal cord and in five regions of adult brain and spinal cord examined by FRIL, no evidence was obtained for the presence of Cx26 in neuronal gap junctions. In addition to its established localization in leptomeningeal gap junctions, these results identify Cx26 as a third connexin (together with Cx30 and Cx43) within astrocytic gap junctions and suggest a further level of complexity to the heterotypic connexin channel combinations formed at these junctions.

Doppler color flow "proximal isovelocity surface area" method for estimating volume flow rate: effects of orifice shape and machine factors

Previously described Doppler color flow mapping methods for estimating the severity of valvular regurgitation have focused on the distal jet. In this study, a newer Doppler color flow technique, focusing on the flow proximal to an orifice, was used. This method identifies a proximal isovelocity surface area (PISA) by displaying an aliasing interface. Volume flow rate (cm3/s) can be calculated as PISA (cm2) x aliasing velocity (cm/s). For planar circular orifices, a hemi-elliptic model accurately approximated the shape of PISA. Clinically, however, orifice shapes may be noncircular. In vitro flow experiments (n = 226) using orifices of various shapes (ellipse, square, triangle, star, rectangle) were performed. Volume flow rate calculated using a hemi-elliptic model for PISA was accurate, with average percent differences from actual flow rate = +4.3% for a square, -4.2% for a triangle, -4.7% for a star, -4.5% for an ellipse and -2.8% for a rectangle. However, average percent differences for calculated volume flow rates using a hemispheric model for PISA shape ranged from -11.6% (square) to -34.8% (rectangle). In addition, to evaluate whether PISA is influenced by machine factors, in vitro studies (n = 83) were performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Contrasting structural impacts induced by cis-syn cyclobutane dimer and (6-4) adduct in DNA duplex decamers: implication in mutagenesis and repair activity

The relative biological importance of cis--syn cyclobutane dimer and pyrimidine(6-4)pyrimidone photoadduct ([6-4] photoadduct) appears to be dependent on the biological species, dipyrimidine sites and local conformational variation induced at the damaged sites. The single-strained deoxynucleotide 10-mers containing the site-specific (6-4) adduct or cis--syn cyclobutane dimer of thymidylyl(3'-->5')-thymidine were generated by direct photolysis of d(CGCATTACGC) with UVC (220-260 nm) irradiation or UVB (260-320 nm) photosensitization. Three-dimensional structures of the duplex cis--syn and (6-4) decamers of d(CGCATTACGC)xd(GCGTAATGCG) were determined by NMR spectroscopy and the relaxation matrix refinement method. The NMR data and structural calculations establish that Watson-Crick base pairing is still intact at the cis--syn dimer site while the hydrogen bonding is absent at the 3'-side of the (6-4) lesion where the T-->C transition mutation is predominantly targeted. Overall conformation of the duplex cis--syn decamer was B-DNA and produced a 9 degree bending in the DNA helix, but a distinctive base orientation of the (6-4) lesion provided a structural basis leading to 44 degree helical bending. The observed local structure and conformational rigidity at the (6-4) adduct of the thymidylyl(3'-5')-thymidine (T-T [6-4]) lesion site suggest the potential absence of hydrogen bonding at the 3' sides of the (6-4) lesion with a substituted nucleotide during replication under SOS conditions. Contrasting structural distortions induced ny the T-T (6-4) adduct with respect to the T-T cis--syn cyclobutane pyrimidine photodimer may explain the large differences in mutation spectrum and repair activities between them.

ELAV protein HuA (HuR) can redistribute between nucleus and cytoplasm and is upregulated during serum stimulation and T cell activation

ELAV proteins are implicated in regulating the stability and translation of cytokine and growth regulatory mRNAs such as GM-CSF, IL-2, c-myc, c-fos and GLUT1 by binding to their AU-rich 3′UTRs. The tissue-specific ELAV protein HuB (aka. Hel-N1) is predominantly cytoplasmic and has been shown to stabilize GLUT1 and c-myc mRNAs and to increase their translation following ectopic expression in 3T3-L1 cells. We report that the most widely expressed mouse ELAV protein, mHuA, is predominately nuclear in cultured NIH-3T3 cells, but is localized in the cytoplasm during early G1 of the cell cycle. Therefore, much like the primarily cytoplasmic HuB, HuA becomes temporally localized in the cytoplasm where it can potentially regulate the stability or translation of bound mRNAs. Moreover, we report that stimulation of mouse spleen cells using either mitogenic or sub-mitogenic levels of anti-CD3/CD28 resulted in a dramatic increase in the level of HuA. Upregulation of HuA corresponds to previously documented increases in cytokine expression which are due to increased mRNA stability following T cell activation. Consistent with these findings, HuA was down regulated in quiescent cells and upregulated in 3T3 cells following serum stimulation. The increase of murine HuA during the cell cycle closely resembles that of cyclin B1 which peaks in G2/M. Together with our earlier studies, these data indicate that mammalian ELAV proteins function during cell growth and differentiation due in part to their effects on posttranscriptional stability and translation of multiple growth regulatory mRNAs. This supports the hypothesis that ELAV proteins can function as transacting factors which affect a default pathway of mRNA degradation involved in the expression of growth regulatory proteins.

Racial differences in the distribution of anterior circulation occlusive disease

We compared clinical and angiographic features of 26 white and 45 black patients with symptomatic occlusive cerebrovascular disease. White patients had more transient ischemic attacks, carotid bruits, and more severe occlusive disease of the internal carotid artery origin. Blacks had more severe disease of the middle cerebral artery stem and supraclinoid internal carotid arteries. Differences were not explained by racial differences in the prevalence of hypertension, diabetes, hypercholesterolemia, or ischemic heart disease. Since the middle cerebral artery lesions in blacks do not correlate with other accepted epidemiologic, clinical, and laboratory markers of atherosclerosis, the lesions may arise from a disorder that differs from atherosclerosis.

Obesity as a risk factor for Alzheimer's disease: weighing the evidence

Alzheimer's disease (AD) is the sixth leading cause of death in the USA today; therefore, it is imperative that public health initiatives and clinical strategies are developed to prevent and effectively treat AD. Despite the enormous impact that AD has on individuals, families, society, and the health care system, there are no biomarkers to clearly identify those at risk for AD, public health prevention strategies in place, or treatments to address the underlying pathology or stop the progression of AD. There is ample scientific as well as empirical evidence that obesity and its metabolic and vascular comorbidities are related to AD and likely in the causative pathway. Obesity prevention and treatment could prove to be an efficacious and safe approach to preventing AD, a serious and daunting epidemic disease. In this review, we present the current pathophysiological and clinical evidence linking obesity and obesity-related comorbidities (eg, insulin resistance, hyperglycaemia, and type 2 diabetes) with AD. Additionally, we discuss which population to target and when to consider treatment for AD. Finally, we summarize the current evidence regarding the efficacy of anti-obesity and anti-diabetic pharmacotherapeutic agents for the treatment of AD.

Evolutionary origins of apoB mRNA editing: catalysis by a cytidine deaminase that has acquired a novel RNA-binding motif at its active site

The site-specific C to U editing of apolipoprotein B100 (apoB100) mRNA requires a 27 kDa protein (p27) with homology to cytidine deaminase. Here, we show that p27 is a zinc-containing deaminase, which operates catalytically like the E. coli enzyme that acts on monomeric substrate. In contrast with the bacterial enzyme that does not bind RNA, p27 interacts with its polymeric apoB mRNA substrate at AU sequences adjacent to the editing site. This interaction is necessary for editing. RNA binding is mediated through amino acid residues involved in zinc coordination, in proton shuttling, and in forming the alpha beta alpha structure that encompasses the active site. However, certain mutations that inactivate the enzyme do not affect RNA binding. Thus, RNA binding does not require a catalytically active site. The acquisition of polymeric substrate binding provides a route for the evolution of this editing enzyme from one that acts on monomeric substrates.

The DNA sequence and biological annotation of human chromosome 1

The reference sequence for each human chromosome provides the framework for understanding genome function, variation and evolution. Here we report the finished sequence and biological annotation of human chromosome 1. Chromosome 1 is gene-dense, with 3,141 genes and 991 pseudogenes, and many coding sequences overlap. Rearrangements and mutations of chromosome 1 are prevalent in cancer and many other diseases. Patterns of sequence variation reveal signals of recent selection in specific genes that may contribute to human fitness, and also in regions where no function is evident. Fine-scale recombination occurs in hotspots of varying intensity along the sequence, and is enriched near genes. These and other studies of human biology and disease encoded within chromosome 1 are made possible with the highly accurate annotated sequence, as part of the completed set of chromosome sequences that comprise the reference human genome.

Occlusive disease of the middle cerebral artery

We studied 20 patients with severe occlusive disease of the mainstem middle cerebral artery (MCA) or its major division branches, and 25 patients with internal carotid artery (ICA) disease. MCA disease patients were more often black, female, younger, and had fewer TIAs than the ICA disease patients. Neurologic signs in patients with MCA disease evolved progressively during days to weeks, whereas ICA disease patients more often had an acute onset of nonprogressive deficits. CT commonly showed restricted subcortical or wedge-shaped infarcts in MCA disease patients. All MCA disease patients had stroke, but 40% of ICA disease patients had no infarction. MCA lesions usually affected the mainstem MCA or its major superior division. Patients with MCA disease seldom had recurrent ischemia in the same vascular territory as the stroke and had a low incidence of subsequent cardiac death.

Fixed- or controlled-dose mycophenolate mofetil with standard- or reduced-dose calcineurin inhibitors: the Opticept trial

Mycophenolate mofetil (MMF) was developed with cyclosporine as a fixed-dose immunosuppressant. More recent data indicate a relationship between mycophenolic acid (MPA) exposure in individuals and clinical endpoints of rejection and toxicity. This 2-year, open-label, randomized, multicenter trial compared the efficacy and safety of concentration-controlled MMF (MMF(CC)) dosing with a fixed-dose regimen in 720 kidney recipients. Patients received either (A) MMF(CC) and reduced-level calcineurin inhibitor (MMF(CC)/CNI(RL)); (B) MMF(CC) and standard-level CNI (MMF(CC)/CNI(SL)); or (C) fixed-dose MMF and CNI(SL) (MMF(FD)/CNI(SL)). Antibody induction and steroid use were according to center practice. The primary endpoint was noninferiority (alpha= 0.05) of group A versus group C for treatment failure (including biopsy-proven acute rejection [BPAR], graft loss and death) at 1 year. Although mean CNI trough levels in group A did not reach the prespecified targets, they were statistically lower than those in groups B and C (p < or = 0.01 for each comparison). BPAR rates (8.5%) were low across groups. Group A had 19% fewer treatment failures (23% vs. 28%, p = 0.18). MMF doses were highest (p < 0.05), with withdrawals for adverse events the fewest (p = 0.02), in group A. Of the 80% of subjects taking tacrolimus (Tac), those with higher MPA exposure had significantly less rejection (p < 0.001) and diarrhea correlated with Tac, but not with MPA levels. Thus, MMF(CC) with low-dose CNI resulted in outcomes not inferior to those with standard CNI exposure and MMF(FD), indicating potential utility of MMF(CC) in CNI-sparing regimens.