CAG expansions in a novel gene for Machado-Joseph disease at chromosome 14q32.1

We have identified a novel gene containing CAG repeats and mapped it to chromosome 14q32.1, the genetic locus for Machado-Joseph disease (MJD). In normal individuals the gene contains between 13 and 36 CAG repeats, whereas most of the clinically diagnosed patients and all of the affected members of a family with the clinical and pathological diagnosis of MJD show expansion of the repeat-number (from 68-79). Southern blot analyses and genomic cloning demonstrates the existence of related genes. These results raise the possibility that similar abnormalities in related genes may give rise to diseases similar to MJD.

GABAergic cell subtypes and their synaptic connections in rat frontal cortex

Physiological, morphological and immunohistochemical characteristics of non-pyramidal cells in frontal cortex of young rats were studied in vitro by whole-cell recording and biocytin injection. Several groups of GABAergic non-pyramidal cells were identified: (i) parvalbumin fast-spiking (FS) cells with low input resistances and spikes of short duration, including extended plexus (basket) cells and chandelier cells. These cells showed abrupt episodes of non-adapting repetitive discharges; (ii) late-spiking (LS) cells exhibiting slowly developing ramp depolarizations, including neurogliaform cells; (iii) the remaining groups contained both burst-spiking (BS) or regular-spiking (RS) non-pyramidal (NP) cells. BSNP cells exhibited bursting activity (two or more spikes on slow depolarizing humps) from hyperpolarized potentials. Both these physiological types corresponded to a range of morphologies: (i) somatostatin-containing Martinotti cells with ascending axonal arbors to layer I (some were also positive for calbindin D28k); (ii) VIP-containing double bouquet cells with descending axonal arbors as well as arcade cells (these included small cells immunoreactive for CCK or calretinin). Each subtype of cells made GABAergic synapses onto relatively specific portions of cortical cells, but similar domains were innervated by multiple classes of GABA cells.

Striatal interneurones: chemical, physiological and morphological characterization

The neostriatum is the largest component of the basal ganglia, and the main recipient of afferents to the basal ganglia from the cerebral cortex and thalamus. Studies of the cellular organization of the neostriatum have focused upon the spiny projection neurones, which represent the vast majority of neurones, but the identity and functions of interneurones in this structure have remained enigmatic despite decades of study. Recently, the discovery of cytochemical markers that are specific for each of the major classes of striatal interneurones, and the combination of this with intracellular recording and staining, has revealed the identities of interneurones and some of their functional characteristics in a way that could not have been imagined by the classical morphologists. These methods also suggest some possible modes of action of interneurones in the neostriatal circuitry.

A genome-wide search for human type 1 diabetes susceptibility genes

We have searched the human genome for genes that predispose to type 1 (insulin-dependent) diabetes mellitus using semi-automated fluorescence-based technology and linkage analysis. In addition to IDDM1 (in the major histocompatibility complex on chromosome 6p21) and IDDM2 (in the insulin gene region on chromosome 11p15), eighteen different chromosome regions showed some positive evidence of linkage to disease. Linkages to chromosomes 11q (IDDM4) and 6q (IDDM5) were confirmed by replication, and chromosome 18 may encode a fifth disease locus. There are probably no genes with large effects aside from IDDM1. Therefore polygenic inheritance is indicated, with a major locus at the major histocompatibility complex.

Susceptibility to human type 1 diabetes at IDDM2 is determined by tandem repeat variation at the insulin gene minisatellite locus

The IDDM2 locus encoding susceptibility to type 1 diabetes was mapped previously to a 4.1-kb region spanning the insulin gene and a minisatellite or variable number of tandem repeats (VNTR) locus on human chromosome 11p15.5. By 'cross-match' haplotype analysis and linkage disequilibrium mapping, we have mapped the mutation IDDM2 to within the VNTR itself. Other polymorphisms were systematically excluded as primary disease determinants. Transmission of IDDM2 may be influenced by parent-of-origin phenomena. Although we show that the insulin gene is expressed biallelically in the adult pancreas, we present preliminary evidence that the level of transcription in vivo is correlated with allelic variation within the VNTR. Allelic variation at VNTRs may play an important general role in human disease.

Intracortical facilitation and inhibition after transcranial magnetic stimulation in conscious humans

1. Changes in excitability of the motor cortex induced by a transcranial magnetic stimulation (TMS) were examined by simultaneous recording of the evoked corticospinal volley and the compound surface electromyographic (EMG) response in the biceps brachii following paired-pulse TMS in five conscious subjects. The effects of a varying interstimulus interval (ISI) and a conditioning stimulus intensity were also investigated. 2. A submotor threshold conditioning stimulus inhibited the test responses at ISIs of 2-5 ms. A supramotor threshold conditioning stimulus inhibited the test responses at ISIs of 100-200 ms. Both of these inhibitions were prominent in late I waves. 3. There was a facilitation of the test responses at an ISI of 25 ms that was prominent in late I waves. The facilitation evoked by the supramotor threshold conditioning stimulus was more prominent than that evoked by the submotor threshold conditioning stimulus. 4. It is concluded that single TMS induced the triphasic changes of the motor cortex excitability in conscious humans that resulted in changes in EMG responses following paired TMS.

Correlation of physiological subgroupings of nonpyramidal cells with parvalbumin- and calbindinD28k-immunoreactive neurons in layer V of rat frontal cortex

1. To test the hypothesis that physiologically and morphologically different cortical nonpyramidal cells express different calcium-binding proteins, whole-cell current-clamp recording in vitro was combined with intracellular staining and double immunofluorescence in layer V of frontal cortex of rats 16-20 days old. 2. Nonpyramidal cells were first characterized as fast-spiking (FS) or low-threshold spike (LTS) cells, injected with biocytin, and subsequently stained immunohistochemically for parvalbumin and calbindinD28k. 3. FS cells were identified by input resistances < 350 M omega, spike width at half amplitude < 0.8 ms, and virtually no spike frequency adaptation of spike trains by depolarizing pulses. LTS cells were identified by input resistances > 350 M omega, spike width at half amplitude > 0.8 ms, and the discharge of low-threshold spikes from hyperpolarized potentials. Repetitive firing could be induced by a combination of stimulation-induced excitatory postsynaptic potentials with depolarization in FS cells. Repetitive firing was not observed in LTS cells under these conditions. 4. After biocytin injection of layer V cells characterized in this way, subsequent double immunostaining showed that all biocytin-labeled parvalbumin-immunoreactive cells (n = 18) belonged to the FS cells (FS-PV cells), whereas all biocytin-labeled calbindinD28k-immunoreactive cells (n = 10) belonged to the LTS cells (LTS-Calb cells). 5. FS-PV cells had smooth or sparsely spiny dendrites, whereas LTS-Calb cells had dendrites with a modest number of spines but fewer than pyramidal cells. FS-PV cells showed denser axonal branches near their somata and extended axons in a more horizontal direction. Some of them could be identified as basket cells by the presence of terminal boutons surrounding somata of other cells. LTS-Calb cells extended their main axons more vertically up to layer I. 6. Double immunofluorescent staining revealed that very few cells in layer V showed immunoreactivity for both calcium-binding proteins but that most cells immunoreactive for the calcium-binding proteins in layer V were also immunoreactive for gamma-aminobutyric acid. 7. These results suggest that GABAergic nonpyramidal cells in layer V of neocortex can be divided into two functional groups on the basis of different firing modes, axonal distributions, and calcium-binding protein immunoreactivity: 1) FS-PV cells show repetitive firing by synaptic activation, have axonal arborizations that are more dense near their somata and oriented horizontally, and the cells exhibit parvalbumin immunoreactivity and 2) LTS cells show low-threshold spikes, have more vertical axonal arborizations up to layer I, and exhibit calbindinD28K immunoreactivity.

Fast spiking cells in rat hippocampus (CA1 region) contain the calcium-binding protein parvalbumin

Fast spiking cells in the CA1 region of the rat hippocampus were revealed as gamma-aminobutyric acid (GABA)ergic non-pyramidal cells containing the calcium-binding protein parvalbumin by intracellular injection of Lucifer yellow in vitro in combination with postembedding parvalbumin immunohistochemistry.

Evidence of association of the ecNOS gene polymorphism with plasma NO metabolite levels in humans

Nitric oxide (NO) synthesized by the vascular endothelium regulates mammalian blood vessels and other systems in humans. Recently, an endothelial nitric oxide synthase (ecNOS) gene polymorphism, the 27-bp repeat in intron 4 (ecNOS4), was reported to be related to the pathogenesis of coronary heart disease and terminal renal failure. We analyzed this polymorphism in a group of 413 healthy subjects, and measured their plasma nitrite and nitrate (NOx) levels. The frequency of the b allele was 89.8% , and the frequency of the a allele was 10.2%. The frequency of ecNOS4 b/b, ecNOS4 b/a, and ecNOS4 a/a in the healthy subjects in this study was 0.814 (n=336), 0.169 (n=70) and 0.017 (n=7), respectively. Using this polymorphism as a DNA marker, we found a strong association between the alleles of the ecNOS gene polymorphism and the plasma NOx levels. The basal NO metabolite levels were 28.8 micromol/L in subjects with ecNOS4 a/a, 31.4 micromol/L in those with ecNOS4 b/a, and 35.5 micromol/L in those with ecNOS4 b/b. The mean plasma NOx level of the subjects who were homozygous for the a allele was nearly 20% lower than in the subjects with the b allele. The plasma NOx level of the subjects with the a allele was 31.2+/-2.00 micromol/L, and significantly lower than the 35.5+/-0.93 micromol/L in those without the a allele (P <0.05). The results of this study indicate that the ecNOS4 gene locus may be responsible for variations in the genetic control of plasma NOx and that analysis of ecNOS4 gene polymorphism may be a useful tool for studying the relation between NO and diseases.

Intracellular recording of identified neostriatal patch and matrix spiny cells in a slice preparation preserving cortical inputs

1. The morphology, electrical membrane properties, and corticostriatal excitatory postsynaptic potentials (EPSPs) of two groups of neostriatal projection cells, patch cells, and matrix spiny cells were compared in the rat by the use of an in vitro slice preparation that preserves inputs from medial agranular cortex. Spiny cells were stained intracellularly with biocytin and identified as belonging to the patch (striosomal) compartment or to the matrix by immunohistochemistry for the 28 kD calcium-binding protein calbindin on the same sections. 2. Patch and matrix neurons had very similar axonal and dendritic morphology. Both patch and matrix cells extended their dendrites and local axon collaterals almost exclusively in their respective compartments. Patch cells and most matrix cells had local axon collaterals within or near the parent dendritic domain. However there was a class of matrix cells that extended axon collaterals over a much wider portion of the neostriatum but still restricted to the matrix compartment. 3. Input resistance and membrane time constant were estimated from the membrane response to intracellularly applied current pulses. The average values of matrix cells were and 8.41 ms. The values of patch cells were 31.8 M omega and 8.19 ms and were within the range of those of matrix cells. Both types of cells showed the same kinds of membrane nonlinearities when tested with the use of current pulses. Input resistance and time constant were both strongly affected by a fast anomalous rectification and were thus voltage-dependent, decreasing with membrane polarization. Slow ramplike depolarizing responses were observed in response to depolarizing current steps. 4. Repetitive firing was examined with the use of depolarizing current pulses. In both types of spiny cells, trains of action potentials showed little adaptation of spike frequency and linearly increased with current intensities less than 1 nA. The slopes frequency, calculated from the first and second intervals, were 115.0 and 107.2 Hz/nA, respectively, for matrix cells and 86.0 and 82.8 Hz/nA for patch cells. 5. Stimulation of the medial agranular cortex induced EPSPs in some striatal cells in both compartments. EPSP in matrix cells often showed both short-latency and long-latency components, corresponding to two early components of the response observed in vivo. Some matrix cells, and all patch cells, showed only the longer latency EPSP component. The average latency was 6.3 ms in matrix cells and 9.1 ms in patch cells. The relationship between EPSP amplitude and membrane potential was nonlinear, with EPSP amplitude and duration increasing with decreasing membrane polarization.(ABSTRACT TRUNCATED AT 400 WORDS)

Reversal of anemia by erythropoietin therapy retards the progression of chronic renal failure, especially in nondiabetic patients

Therapy with human recombinant erythropoietin (EPO) has been accepted as effective for renal anemia in dialysis patients. However, studies in rats have shown that correcting anemia with EPO may affect the progression of renal dysfunction. In humans, however, the effect of EPO on residual renal function is a matter of controversy. We, therefore, investigated whether the long-term administration of EPO to predialysis patients influences residual renal function. Anemic patients at the predialysis stage with a serum creatinine (Cr) concentration ranging from 2 to 4 (average 2.9) mg/dl and a hematocrit (Ht) of less than 30% were randomly assigned to two groups which consisted of anemic patients not treated with EPO (group I, untreated anemic controls, n = 31) and anemic patients treated with EPO (group II, treated anemics, n = 42). Patients with nonsevere or moderate anemia (Ht > 30%) with a Cr ranging from 2 to 4 (average 2.6) mg/dl were also recruited as nonanemic controls (group III, untreated nonanemic controls, n = 35). Blood pressure was controlled to the same degree among the three groups by combined treatment with calcium antagonists and angiotensin-converting enzyme inhibitors. All patients were kept strictly on a low-protein (0.6 g/kg/day) and a low-salt (7 g/day) diet. The degree of control of dietary protein and blood pressure and the frequency of angiotensin-converting enzyme inhibitor administration were comparable among the three groups. The primary end point for each patient was a doubling of the baseline Cr which yielded cumulative renal survival rates which were plotted against time. Ht rose significantly from 27.0+/-2.3 to 32.1+/-3.2% in group II (n = 42, p < 0.001) with a rate of increase of 0.4+/-0.06%/week. However, it declined from 27.9+/-1.8 to 25.3+/-1.9% in group I (n = 31, p < 0.001) and from 35.9+/-3.5 to 32.2+/-3.9% in group III (n = 35, p < 0.001). Cr doubled in 26 patients (84%) in group I as compared with 22 (52%) in group II and 21 (60%) in group III. The cumulative renal survival rates in groups II and III were significantly better than that in group I: p = 0.0003 (group I vs. group II) and p = 0.0024 (group I vs. group III). However, there was no difference in the renal survival rate between groups II and III (p = 0.3111). The better survival rate obtained in group II was attributable to the better survival rate for the nondiabetic patients in this group. The present study suggests that anemia, per se, is a factor in the progression of end-stage renal failure and that reversal of anemia by EPO can retard the progression of renal failure, especially in nondiabetic patients, provided that blood pressure control, rate of increase in Ht, and dietary protein restriction are appropriate.

Groupings of nonpyramidal and pyramidal cells with specific physiological and morphological characteristics in rat frontal cortex

1. Physiological and morphological properties of layer V non-pyramidal and pyramidal cells in isolated slices of frontal cortex from young rats (16-22 days postnatal) were studied by whole-cell, current-clamp recording of visualized cell bodies coupled with intracellular staining by biocytin at 26-27 degrees C. 2. Plotting of spike width at half amplitude against input resistance revealed two physiological categories of nonpyramidal cells. One class (n = 29) had input resistances lower than 400 M omega and spike widths at half amplitude shorter than 0.8 ms; the other (n = 22) had input resistances higher than 400 M omega and spike widths longer than 0.8 ms. According to their spike firing characteristics, the former are called fast-spiking (FS) cells, and the latter low-threshold spike (LTS) cells. 3. Resting potentials were more negative in FS cells than in LTS cells. Membrane time constants in LTS cells were four times larger than those of FS cells. Afterhyperpolarizations (AHPs) following action potentials consisted of a single component in FS cells, but two components with early and late peaks were observed in LTS cells. AHPs of FS cells had faster time-to-peak and larger amplitude than the early component of the AHPs of LTS cells. 4. Low-threshold spikes induced by depolarizing current pulses were observed at hyperpolarized potentials in LTS cells, but not in FS cells. The low-threshold spikes in LTS cells could be activated at hyperpolarized potentials by synaptic potentials. 5. Spike trains elicited by depolarizing current pulses in FS cells showed almost no spike-frequency adaptation, whereas those in LTS cells showed adaptation. 6. Excitatory postsynaptic potentials (EPSPs) of both groups of nonpyramidal cells contained N-methyl-D-aspartate (NMDA) receptor-mediated components. A combination of stimulation-induced EPSPs with depolarization caused repetitive firing in FS cells that was abolished by NMDA receptor blockers. Repetitive firing was not observed in LTS cells under these conditions. 7. The somal size of the two classes of nonpyramidal cells was similar. FS cells were all multipolar in shape, whereas LTS cells included both multipolar and bitufted types. The dendrites of some FS cells extended up into layers II/III, but there were also other FS cells with their dendrites restricted in layer V. Dendrites of LTS cells were mostly restricted to layer V. Dendrites of FS cells were mostly smooth, but those of LTS cells possessed a modest but consistent population of spines.(ABSTRACT TRUNCATED AT 400 WORDS)

Back muscle injury after posterior lumbar spine surgery. A histologic and enzymatic analysis

STUDY DESIGN

Back muscle injury after posterior lumbar surgery was studied by muscle histology and serum creatine phosphokinase MM isoenzyme activity.

OBJECTIVES

To investigate intraoperative factors influencing the magnitude of back muscle injury after posterior lumbar surgery.

SUMMARY OF BACKGROUND DATA

The authors previously have reported iatrogenic back muscle injury in an animal model and in humans. Serious injury of the back muscle has been shown by short-term and long-term follow-up evaluation.

METHODS

The retraction pressure was monitored, and the retraction pressure-time products were calculated in 24 patients. Early histologic changes of multifidus muscle, which were taken at completion of surgery, and serum creatine phosphokinase MM isoenzyme activity changes were examined.

RESULTS

The magnitude of back muscle injury was significant as the pressure-time product increased. Creatine phosphokinase MM isoenzyme activity increased after surgery and reached a plateau 1 day after surgery, followed by recovery to the normal value 1 week after surgery. Creatine phosphokinase MM isoenzyme activity tended to be high in cases with multilevel exposure and with high pressure-time product.

CONCLUSIONS

Back muscle injury occurs in all patients who underwent posterior lumbar surgery, and these injuries are related to the retraction pressure, time, and extent of exposure.

Immunohistochemical detection of advanced glycosylation end-products in the peritoneum and its possible pathophysiological role in CAPD

It has recently been suggested that advanced glycosylation end-products (AGEs) are formed in the peritoneum in patients on CAPD. However, the exact location of AGE accumulation, the relation with the duration of CAPD and its pathophysiological role in CAPD remain unclear. If the peritoneum is glycosylated, it could bring about altered peritoneal function. Therefore, the aim of this study is to clarify the localization of AGEs in the peritoneum in accordance with the duration of CAPD and to examine its relation to the peritoneal permeability. Fifteen non-diabetic patients were divided into three groups (each 5 patients) on the basis of the mean duration (D) of CAPD (Group 1, D = 0 month; Group II, D = 34 months; Group III, D = 84 months). The AGE staining by monoclonal anti-AGE antibody in the peritoneum and the four-hour peritoneal equilibration test (PET) were compared among these groups. AGE was absent or found only weakly in Group I. However, in groups II and III, AGE was moderately or strongly positive especially in the vascular walls and it was dominant in group III. PET revealed that peritoneal permeability for glucose, creatinine, beta2-microglobulin and albumin was increased in Group II as compared to Group I, and it was further increased in Group III. The results of this study indicate that AGEs become dominantly accumulated in the vascular wall in accordance with the prolongation of CAPD treatment, and this might play some roles for the increased permeability of the peritoneal membrane in CAPD.

Serial changes in trunk muscle performance after posterior lumbar surgery

STUDY DESIGN

Serial changes in trunk muscle performance were prospectively studied in 20 patients who underwent posterior lumbar surgery.

OBJECTIVE

To evaluate the influence of back muscle injury on postoperative trunk muscle performance and low back pain, to clarify the significance of minimization of back muscle injury during surgery.

SUMMARY OF BACKGROUND DATA

The current investigators have reported examination of iatrogenic back muscle injury in an animal model and in humans. However, definite impairment caused by such back muscle injury has not been clarified.

METHODS

The patients were divided into a short-retraction-time group (< 80 minutes; n = 12) and a long-retraction-time group (> or = 80 minutes; n = 8). Before surgery and 3 and 6 months after surgery, the degree of back muscle injury was estimated by magnetic resonance imaging, and trunk muscle strength was measured. In addition, the incidence and severity of low back pain were serially analyzed.

RESULTS

Back muscle injury was directly related to the muscle retraction time during surgery. The damage to the multifidus muscle was more severe, and the recovery of extensor muscle strength was delayed in the long-retraction-time group. In addition, the incidence of postoperative low back pain was significantly higher in the long-retraction-time group.

CONCLUSIONS

Postoperative trunk muscle performance is dependent on the muscle retraction time. Thus, it is beneficial to shorten the retraction time to minimize back muscle injury and subsequent postoperative low back pain.

Neurochemical features and synaptic connections of large physiologically-identified GABAergic cells in the rat frontal cortex

Physiological and morphological properties of large non-pyramidal cells immunoreactive for cholecystokinin, parvalbumin or somatostatin were investigated in vitro in the frontal cortex of 18-22-day-old rats. These three peptides were expressed in separate populations including large cells. Cholecystokinin cells and parvalbumin cells made boutons apposed to other cell bodies, but differed in their firing patterns in response to depolarizing current pulses. Parvalbumin cells belonged to fast-spiking cells. Parvalbumin fast-spiking cells also included chandelier cells. In contrast, cholecystokinin cells were found to be regular-spiking non-pyramidal cells or burst-spiking non-pyramidal cells with bursting activity from hyperpolarized potentials (two or more spikes on slow depolarizing humps). Large somatostatin cells belonged to the regular-spiking non-pyramidal category and featured wide or ascending axonal arbors (wide arbor cells and Martinotti cells) which did not seem to be apposed to the somata so frequently as large cholecystokinin and parvalbumin cells. For electron microscopic observations, another population of eight immunohistochemically-uncharacterized non-pyramidal cells were selected: (i) five fast spiking cells including one chandelier cell which are supposed to contain parvalbumin, and (ii) three large regular-spiking non-pyramidal cells with terminals apposed to somata, which are not considered to include somatostatin cells, but some of which may belong to cholecystokinin cells. The fast-spiking cells other than a chandelier cell and the large regular-spiking non-pyramidal cells made GABA-positive synapses on somata (4% and 12% of the synapses in two small to medium fast-spiking cells, 22% and 35% of the synapses in two large fast-spiking cells, and 10%, 18% and 37% of the synapses in three large regular-spiking non-pyramidal cells). A few terminals of the fast-spiking and regular-spiking non-pyramidal cells innervated GABAergic cells. About 30% of the fast-spiking cell terminals innervated spines, but few of the regular-spiking non-pyramidal cell terminals did. A fast-spiking chandelier cell made GABA-positive synapses on GABA-negative axon initial segments. These results suggest that large GABAergic cells are heterogeneous in neuroactive substances, firing patterns and synaptic connections, and that cortical cells receive heterogeneous GABAergic somatic inputs.

Herpes simplex virus 1 alpha regulatory protein ICP0 interacts with and stabilizes the cell cycle regulator cyclin D3

The herpes simplex virus 1 (HSV-1) infected-cell protein 0 (ICP0) has the characteristics of a promiscuous transactivator of genes introduced into cells by infection or transfection. To identify cellular proteins interacting with ICP0, we used a domain of exon II of ICP0 that is known to be crucial for regulatory function of the protein as bait in the yeast two-hybrid screen. Our results were as follows. (i) A cDNA in a positive yeast colony was found to encode cyclin D3, a cell cycle regulator of G1 phase. (ii) A purified chimeric protein consisting of glutathione S-transferase (GST) fused to cyclin D3 specifically formed complexes with ICP0 contained in HSV-1-infected cell lysate. (iii) To enhance the expression of cyclin D3, the gene was inserted into the viral genome and overexpressed in infected cells. The overexpressed cyclin D3 colocalized with ICP0 in nuclear structures characteristic of ND10 and which earlier have been reported to contain ICP0. (iv) The accumulation of cyclin D3 protein in Vero cells infected with an alpha0 deletion mutant was reduced relative to that of cells infected with wild-type virus or a recombinant virus in which the deleted alpha0 sequences were restored. (v) Lysates of Spodoptera frugiperda Sf9 cells doubly infected with baculoviruses genetically engineered to express cyclin D3 and cyclin-dependent kinase 4 (CDK4) phosphorylated GST fused to retinoblastoma protein (GST-pRb) but did not phosphorylate the GST-alpha0(20-241) or GST-alpha0(543-768) fusion protein or immunoprecipitated ICP0 proteins. Moreover, the chimeric GST-ICP0(exon II) protein shown to bind cyclin D3 had no effect on the activity of the kinase on GST-pRb when added to mixtures of lysates of Sf9 cells which coexpressed cyclin D3 and CDK4. These results indicate that ICP0 interacts with, colocalizes with, and stabilizes the cyclin D3 cell cycle regulator and does not affect its interaction with the cyclin-dependent kinase.

Role of the deletion of polymorphism of the angiotensin converting enzyme gene in the progression and therapeutic responsiveness of IgA nephropathy

Studies conducted over the last decade demonstrated variable therapeutic efficacy of angiotensin converting enzyme (ACE) inhibitor on the progression of glomerular diseases, including IgA nephropathy. In this study, among patients with biopsy-proven IgA nephropathy, 53 patients in whom creatinine clearance had been monitored over 5 yr were recruited for study. These patients were classified into two groups according to whether or not renal function had declined as determined by the slope of creatinine clearance against time: group 1 had stable renal function; group 2 had declining renal function (average: -6.7 +/- 1.3 ml/min/yr). 21 of 53 patients were treated with ACE inhibitor and followed for 48 wk. Gene polymorphism consisting of insertion (I) or deletion (D) of a 287-bp DNA fragment (presumed to be a silencer element) of the ACE gene was determined by PCR. 46 age-matched individuals without history of proteinuria were analyzed as controls. The DD genotype was significantly more frequent in group 2 (43%) than in controls (7%) or group 1 patients with stable renal function (16%). 48 wk after ACE inhibitor administration, proteinuria significantly decreased in patients with DD genotype but not in those with ID or II genotypes. The results indicate that deletion polymorphism in the ACE gene, particularly the homozygote DD, is a risk factor for progression to chronic renal failure in IgA nephropathy. Moreover, this deletion polymorphism predicts the therapeutic efficacy of ACE inhibition on proteinuria and, potentially, on progressive deterioration of renal function.

Chromosome-specific microsatellite sets for fluorescence-based, semi-automated genome mapping

To facilitate large-scale genetic mapping of the human genome, we have developed chromosome-specific sets of microsatellite marker loci suitable for use with a fluorescence-based automated DNA fragment analyser. We present 254 dinucleotide repeat marker loci (80% from the Généthon genetic linkage map) arranged into 39 sets, covering all 22 autosomes and the X chromosome. The average distance between adjacent markers is 13 centiMorgans, and less than 4% of the genome lies more than 20 cM from the nearest marker. Each set of microsatellites consists of up to nine marker loci, with allele size ranges that do not overlap. We selected marker loci on the basis of their reliability in the polymerase chain reaction, polymorphism content, map position and the accuracy with which alleles can be scored automatically by the Genotyper program.

Neostriatal cell subtypes and their functional roles

The neostriatum is considered to be involved in the induction of purposeful movements or in the suppression of other movements through the internal segment of the globus pallidus (GP; the entopeduncular nucleus in the rodents) and the substantia nigra (SN) to which the striatal spiny neurons project. To understand how the striatum fulfills these functions, it is necessary to know the physiological and morphological characteristics of its constituent neurons. Aspiny interneurons in the striatum are considered to receive various excitatory inputs and to contribute importantly to determining whether spiny projection neurons fire or not. Both spiny and aspiny striatal cells have been shown to be heterogeneous in their physiological, chemical and connection characteristics. In this article, how these cell subtypes are organized in the local circuitry of the striatum and their physiological roles in the basal ganglia are discussed.

The codon CUG is read as serine in an asporogenic yeast Candida cylindracea

Deviations from the universal genetic code have been reported for several microorganisms. Termination codons are used for coding some amino acids in Paramecium, Mycoplasma or Tetrahymena, and in Escherichia coli, the UGA termination codon is used to code for selenocysteine. In mitochondria, the changes of sense codons to termination codons or to codons encoding other amino acids have also been reported. Here we report another example of divergence from the universal code, this time in a non-spore-forming yeast Candida cylindracea, in which the universal codon for leucine, CUG, is used to code for serine. This conclusion is based on the observations that: (1) the amino-acid composition and the partial amino-acid sequences of an extracellular lipase from this yeast agreed with those deduced from the complementary DNA if CUG was assumed to specify serine; and (2) serine, but not leucine, was incorporated into a polypeptide in a cell-free translation system from this yeast in the presence of a synthetic CUG oligomer.

Selective cholinergic modulation of cortical GABAergic cell subtypes

Acetylcholine from the basal forebrain and gamma-aminobutyric acid (GABA) from intracortical inhibitory interneurons exert strong influence on the cortical activity and may interact with each other. Cholinergic or muscarinic agonists indeed induced GABAergic postsynaptic currents in pyramidal cells by exciting inhibitory interneurons that have recently been classified into several distinct subtypes on the basis of the physiological, chemical, and morphological criteria. Cholinergic effects on GABAergic cell subtypes were investigated of rat frontal cortex by in vitro whole cell recording with intracellular staining in frontal cortex of young rats. GABAergic cell subtypes were identified physiologically by firing responses to depolarizing current pulses and immunohistochemically as containing parvalbumin, somatostatin, vasoactive intestinal polypeptide (VIP), or cholecystokinin (CCK). Carbachol (10 microM) or (+)-muscarine (3 microM) affected the activities of peptide-containing GABAergic cells with regular- or burst-spiking characteristics, but not of GABAergic cells with fast-spiking characteristics containing the calcium-binding protein parvalbumin or GABAergic cells with late-spiking characteristics. Somatostatin- or VIP-immunoreactive cells were depolarized with spike firing. CCK-immunoreactive cells were affected heterogeneously by cholinergic agonists. Larger CCK cells were hyperpolarized, followed by a slow depolarization, whereas smaller CCK cells were only depolarized. These results suggest that the excitability of cortical GABAergic cell subtypes is differentially regulated by acetylcholine. Differences in cholinergic responses suggest a distinct functional role of each GABAergic cell subtype.

The Pro12 -->Ala substitution in PPAR-gamma is associated with resistance to development of diabetes in the general population: possible involvement in impairment of insulin secretion in individuals with type 2 diabetes

The allele frequencies for a Pro12-->Ala substitution in peroxisome proliferator-activated receptor-gamma differ among ethnic groups, and its relationship with diabetes and associated diseases is controversial. The prevalence of this polymorphism and its effects on clinical characteristics have now been evaluated with a large number of Japanese individuals with type 2 diabetes (n = 2,201) and normal control subjects (n = 1,212) recruited by 10 institutions located in seven different cities in Japan. The allele frequency for the Ala12 variant was significantly lower in the type 2 diabetic group than in the control group (2.39 vs. 4.13%, P = 0.000054). However, compared with subjects without the Ala12 variant, the diabetic subjects with this variant exhibited a significantly higher serum concentration of total cholesterol (P = 0.001), manifested a reduced capacity for insulin secretion as evaluated by homeostasis model assessment (P = 0.007), and tended to possess a higher level of HbA1c. These data suggest that the Ala12 variant is associated with a reduced risk for the development of diabetes in the general population, but that it may be also a risk factor for insulin deficiency and disease severity in individuals with type 2 diabetes.

Learning curve for laparoscopic major hepatectomy

BACKGROUND

Laparoscopic major hepatectomy (LMH) is evolving as an important surgical approach in hepatopancreatobiliary surgery. The present study aimed to evaluate the learning curve for LMH at a single centre.

METHODS

Data for all patients undergoing LMH between January 1998 and September 2013 were recorded in a prospective database and analysed. The learning curve for operating time (OT) was evaluated using the cumulative sum (CUSUM) method.

RESULTS

Of 173 patients undergoing major hepatectomy, left hepatectomy was performed in 28 (16·2 per cent), left trisectionectomy in nine (5·2 per cent), right hepatectomy in 115 (66·5 per cent), right trisectionectomy in 13 (7·5 per cent) and central hepatectomy in eight (4·6 per cent). Median duration of surgery was 270 (range 100-540) min and median blood loss was 300 (10-4500) ml. There were 20 conversions to an open procedure (11·6 per cent). Vascular clamping was independently associated with conversion on multivariable analysis (hazard ratio 5·95, 95 per cent c.i. 1·24 to 28·56; P = 0·026). The CUSUMOT learning curve was modelled as a parabola (CUSUMOT  = 0·2149 × patient number(2)  - 30·586 × patient number - 1118·3; R(2)  = 0·7356). The learning curve comprised three phases: phase 1 (45 initial patients), phase 2 (30 intermediate patients) and phase 3 (the subsequent 98 patients). Although right hepatectomy was most common in phase 1, a significant decrease was observed from phase 1 to 3 (P = 0·007) in favour of more complex procedures.

CONCLUSION

The learning curve for LMH consisted of three characteristic phases identified by CUSUM analysis. The data suggest that the learning phase of LMH included 45 to 75 patients.