[Cardiac amyloidosis: pathological classification and clinical analysis of 48 cases]

Objective: To investigate the histological features and clinical manifestations in different types of cardiac amyloidosis to improve diagnostic accuracy. Methods: The histopathological features and clinical manifestations of 48 patients diagnosed with cardiac amyloidosis by Congo red stain and electron microscopy through endomyocardial biopsy were collected in West China Hospital of Sichuan University from January 2018 to December 2021. Immunohistochemical stains for immunoglobulin light chains (κ and λ) and transthyretin protein were carried out, and a review of literature was made. Results: The patients age ranged from 42 to 79 years (mean 56 years) and the male to female ratio was 1.1 to 1.0. The positive rate of endomyocardial biopsy was 97.9% (47/48), which was significantly higher than that of the abdominal wall fat (7/17). Congo red staining and electron microscopy were positive in 97.9% (47/48) and 93.5% (43/46), respectively. Immunohistochemical stains showed 32 cases (68.1%) were light chain type (AL-CA), including 31 cases of AL-λ type and 1 case of AL-κ type; 9 cases (19.1%) were transthyretin protein type (ATTR-CA); and 6 cases (12.8%) were not classified. There was no significant difference in the deposition pattern of amyloid between different types (P>0.05). Clinical data showed that ATTR-CA patients had less involvement of 2 or more organs and lower N-terminal pro-B-type natriuretic peptide (NT-proBNP) than the other type patients (P<0.05). The left ventricular stroke volume and right ventricular ejection fraction of ATTR-CA patients were better than the other patients (P<0.05). Follow-up data of 45 patients was obtained, and the overall mean survival time was 15.6±2.0 months. Univariate survival analysis showed that ATTR-CA patients had a better prognosis, while cardiac amyloidosis patients with higher cardiac function grade, NT-proBNP >6 000 ng/L, and troponin T >70 ng/L had a worse prognosis (P<0.05). Multivariate survival analysis showed that NT-proBNP and cardiac function grade were independent prognostic factors for cardiac amyloidosis patients. Conclusions: AL-λ is the most common type of cardiac amyloidosis in this group. Congo red staining combined with electron microscopy can significantly improve the diagnosis of cardiac amyloidosis. The clinical manifestations and prognosis of each type are different and can be classified based on immunostaining profile. However, there are still a few cases that cannot be typed; hence mass spectrometry is recommended if feasible.

Direct acceleration of collimated monoenergetic sub-femtosecond electron bunches driven by a radially polarized laser pulse

High-quality ultrashort electron beams have diverse applications in a variety of areas, such as 4D electron diffraction and microscopy, relativistic electron mirrors and ultrashort radiation sources. Direct laser acceleration (DLA) mechanism can produce electron beams with a large amount of charge (several to hundreds of nC), but the generated electron beams usually have large divergence and wide energy spread. Here, we propose a novel DLA scheme to generate high-quality ultrashort electron beams by irradiating a radially polarized laser pulse on a nanofiber. Since electrons are continuously squeezed transversely by the inward radial electric field force, the divergence angle gradually decreases as electrons transport stably with the laser pulse. The well-collimated electron bunches are effectively accelerated by the circularly-symmetric longitudinal electric field and the relative energy spread also gradually decreases. It is demonstrated by three-dimensional (3D) simulations that collimated monoenergetic electron bunches with 0.75° center divergence angle and 14% energy spread can be generated. An analytical model of electron acceleration is presented which interprets well by the 3D simulation results.

[Epithelioid glioblastoma with BRAF V600E mutation: a clinicopathological and molecular study]

Objective: To investigate the clinicopathological and molecular characteristics of the epithelioid glioblastoma (eGBM) with BRAF V600E mutation. Methods: Sixteen cases of eGBM with BRAF V600E mutation diagnosed at the West China Hospital of Sichuan University, China from 2012 to 2019 were collected. Their clinicopathological and molecular characteristics were analyzed. Results: The range of patients' age was from 7 to 61 years (median 31.5 years). There were 4 males and 12 females, with a male to female ratio of 1∶3. Eleven cases were newly diagnosed eGBM and five cases had a previous history of astrocytomas. Most of the tumors were located in the cerebral hemisphere, often in the frontal lobe, with an average diameter of 4.6 cm (2.0-8.0 cm). The tumors were composed of relatively uniform, closely packed epithelioid cells, some showing discohesion, with distinct cell membrane, eosinophilic cytoplasm, eccentric nuclei, distinct nucleoli and mitotic activity. Palisaded/coagulative necrosis was seen in all cases. Glomerular microvascular proliferation was seen in most of the cases, while mono-or multi-nucleated tumor giant cells were seen in some cases. Focal sarcomatoid area was seen in 2 cases, and focal pleomorphic xanthoastrocytoma (PXA)-like area was seen in 3 cases. Immunohistochemistry showed variable positivity for GFAP, Olig2 and p53. The median Ki-67 index was 30% (10%-50%). Only one case lost ATRX protein expression. Sanger sequencing identified the BRAF V600E mutation in all sixteen patients. Five cases also had mutations in the TERT gene promoter. No IDH1 (R132) or IDH2 (R172) mutation was detected. Surgical resection of the tumors was performed for all patients, and 3 patients also received adjuvant radiotherapy and chemotherapy. Follow-up data were available for 15 patients, with a follow-up time of 1-89 months (median 10 months). Among the 15 patients, 7 patients died of disease and another 5 patients had recurrences. The overall survival time of the patients under 35 years of age was significantly longer than that of the patients aged 35 years or older (P=0.014), but their progression-free survival was not statistically different (P=0.232). Conclusions: eGBM with BRAF V600E mutation is more commonly detected in young women than other the populations (i.e. elderly or male). The epithelioid morphology should include rhabdoid meningioma, anaplastic PXA, atypical teratoid/rhabdoid tumor, metastatic tumors, and melanoma in its differential diagnosis. PXA-like area is observed in some eGBM cases, suggesting a relationship of these two types of tumor. eGBM is a high-grade malignant tumor and most of the cases show recurrences or deaths in a short-period time. The younger patients have a relatively better prognosis than the older ones.

[Prognostic significance of combined TERT and IDH gene mutation analysis in diffusely infiltrating gliomas]

Objective: To investigate the status and prognostic significance of TERT and IDH1/2 genes mutations in diffusely infiltrating gliomas. Methods: Hot spot mutations of TERT and IDH1/2 genes were detected by DNA sequencing in 236 cases of gliomas at West China Hospital from 2012 to 2016, including pilocytic astrocytoma (WHO grade Ⅰ, 16 cases), diffuse astrocytoma and oligodendroglioma (WHO grade Ⅱ, 89 cases), anaplastic astrocytoma and oligodendroglioma (WHO grade Ⅲ, 72 cases) and glioblastoma (WHO grade Ⅳ, 59 cases). The prognostic significance of TERT and IDH1/2 hot spot mutations was evaluated. Results: No IDH or TERT mutations were detected in pilocytic gliomas. TERT promoter mutation frequency was higher in patients aged ≥40 years(60.8%, 93/153) than in patients aged <40 years (32.8%, 22/67; P<0.01). TERT promoter mutation rate was also significantly higher in oligodendroglioma (87.5% , 56/64) than that in astrocytoma(37.8%, 59/156; P<0.01). Young age (<40 years), oligodendroglioma and IDH1 mutation were favorable prognostic factors for diffusely infiltrating astrocytic and oligodendroglial tumors. TERT mutation alone was not of prognostic significance. Diffusely infiltrating astrocytic and oligodendroglial tumors were divided into four molecular subtypes according to TERT and IDH1 mutation status: IDH(+ )/TERT(+ ), IDH(+ )/TERT(-), IDH(-)/TERT(-) and IDH(-)/TERT(+ ). There was significant prognostic difference among the 4 subtypes. Conclusions: Combined IDH and TERT gene mutation analysis may be useful for prognostic subgrouping. Notably, IDH1 wild-type cases can be further subdivided into TERT(+ ) or (-) subgroups with significant prognostic difference.

Numerical investigation of the transverse instability on the radiation-pressure-driven foil

The development of transverse instability in the radiation-pressure-acceleration dominant laser-foil interaction is numerically examined by two-dimensional particle-in-cell simulations. When a plane laser impinges on a foil with modulated surface, the transverse instability is incited, and periodic perturbations of the proton density develop. The growth rate of the transverse instability is numerically diagnosed. It is found that the linear growth of the transverse instability lasts only a few laser periods, then the instability gets saturated. In order to optimize the modulation wavelength of the target, a method of information entropy is put forward to describe the chaos degree of the transverse instability. With appropriate modulation, the transverse instability shows a low chaos degree, and a quasi-monoenergetic proton beam is produced.

Generation of bright attosecond x-ray pulse trains via Thomson scattering from laser-plasma accelerators: errata

We report and correct a couple of calculation errors in the x-ray flux and maximum peak brightness in our paper [Opt. Express 22, 32098 (2014)].

Generation of bright attosecond x-ray pulse trains via Thomson scattering from laser-plasma accelerators

Generation of attosecond x-ray pulse attracts more and more attention within the advanced light source user community due to its potentially wide applications. Here we propose an all-optical scheme to generate bright, attosecond hard x-ray pulse trains by Thomson backscattering of similarly structured electron beams produced in a vacuum channel by a tightly focused laser pulse. Design parameters for a proof-of-concept experiment are presented and demonstrated by using a particle-in-cell code and a four-dimensional laser-Compton scattering simulation code to model both the laser-based electron acceleration and Thomson scattering processes. Trains of 200 attosecond duration hard x-ray pulses holding stable longitudinal spacing with photon energies approaching 50 keV and maximum achievable peak brightness up to 10²⁰ photons/s/mm²/mrad²/0.1%BW for each micro-bunch are observed. The suggested physical scheme for attosecond x-ray pulse trains generation may directly access the fastest time scales relevant to electron dynamics in atoms, molecules and materials.

Electron density compression and oscillating effects on laser energy absorption in overdense plasma targets

An analytical model for energy absorption during the interaction of an ultrashort, ultraintense laser with an overdense plasma is proposed. Both the compression effect of the electron density profile and the oscillation of the electron plasma surface are self-consistently included, which exhibit significant influences on the laser energy absorption. Based on our model, the general scaling law of the compression effect depending on laser strength and initial density is derived, and the temporal variation of the laser absorption due to the boundary oscillating effect is presented. It is found that due to the oscillation of the electron plasma surface, the laser absorption rate will vibrate periodically at ω or 2ω frequency for the p-polarized and s-polarized laser, respectively. The effect of plasma collision on the laser absorption has also been investigated, which shows a considerable rise in absorption with increasing electron-ion collision frequency for both polarizations.

Simultaneous generation of monoenergetic tunable protons and carbon ions from laser-driven nanofoils

Simultaneous generation of monoenergetic tunable protons and carbon ions from intense laser multi-component nanofoil interaction is demonstrated by using particle-in-cell simulations. It is shown that, the protons with the largest charge-to-mass ratio are instantly separated from other ion species and are efficiently accelerated in the "phase stable" way. The carbon ions always ride on the heavier oxygen ion front with an electron-filling gap between the protons and carbon ions. At the cost of widely spread oxygen ions, monoenergetic collimated protons and carbon ions are obtained simultaneously. By modulating the heavier ion densities in the foil, it is capable to control the final beam quality, which is well interpreted by a simple analytical model.

Effect of the prior distribution of SNP effects on the estimation of total breeding value

Background

Five main methods, commonly applied in genomic selection, were used to estimate the GEBV on the 15^th QTLMAS workshop dataset: GBLUP, LASSO, Bayes A and two Bayes B type of methods (BBn and BBt). GBLUP is a mixed model approach where GEBV are obtained using a relationship matrix calculated from the SNP genotypes. The remaining methods are regression-based approaches where the SNP effects are first estimated and, then GEBV are calculated given the individuals' genotypes.

Methods

The differences between the regression-based methods are in their prior distributions for the SNP effects. The prior distribution for LASSO is a Laplace distribution, for Bayes A is a scaled Student-t distribution, and the Bayes B type methods have a Spike and Slab prior where only a proportion (π) of SNP has an effect, following a given distribution. In this study, two different distributions were considered for the Bayes B type methods: (i) normal and (ii) scaled Student-t. They are referred here as the BBn and BBt methods, respectively. These prior distributions are defined by one or more parameters controlling their scale/rate (λ), shape (df) or proportion of SNP with effect (π). LASSO requires one (λ); two for Bayes A (λ, df) and Bayes Bn (λ, π); and three for Bayes Bt (λ, df, π). In this study, all parameters were estimated from the data. An extra scenario for Bayes A and BBt was included where df was not estimated but fixed to 4 (suffixed _4df). The implementation of GBLUP was done using ASREML, the heritability was also estimated from the data. All other methods were implemented using a MCMC approach.

Results

All Bayes A and B methods showed accuracy (correlation between True and Estimated BV) as high as 0.94 except for BA_4df (r = 0.91). Compared to the traditional BLUP using pedigree information, these methods improved the accuracy between 50 and 55%. GBLUP and LASSO were less accurate (0.81 and 0.85 respectively) and the improvements were 34 and 40% compared to BLUP.

Conclusions

Results of all methods were consistent and the accuracies for GEBV ranged between 0.81 and 0.94. When all parameters were estimated the results were similar for the Bayes A and Bayes B methods. Results showed that Bayes A was more sensitive to the changes in the shape parameter, and the parameter changes led to change in the accuracy of GEBV. However BBt was more robust to the change in this parameter. This may be explained by the fact that BBt estimates one extra parameter and it can buffer against a non-proper shape parameter.

Electron bow-wave injection of electrons in laser-driven bubble acceleration

An electron injection regime in laser wake-field acceleration, namely electron bow-wave injection, is investigated by two- and three-dimensional particle-in-cell simulation as well as analytical model. In this regime electrons in the intense electron bow wave behind the first bubble catch up with the bubble tail and are trapped by the bubble finally, resulting in considerable enhancement of the total trapped electron number. For example, with the increase of the laser intensity from 2 × 10(19) to 1 × 10(20) W/cm(2), the electron trapping changes from normal self-injection to bow-wave injection and the trapped electron number is enhanced by two orders of magnitude. An analytical model is proposed to explain the numerical observation.

Enhanced collimated GeV monoenergetic ion acceleration from a shaped foil target irradiated by a circularly polarized laser pulse

Using multidimensional particle-in-cell simulations we study ion acceleration from a foil irradiated by a circularly polarized laser pulse at 10;{22} W/cm;{2} intensity. When the foil is shaped initially in the transverse direction to match the laser intensity profile, three different regions (acceleration, transparency, and deformation region) are observed. In the acceleration region, the foil can be uniformly accelerated for a longer time compared to a usual flat target. Undesirable plasma heating is effectively suppressed. The final energy spectrum of the accelerated ion beam in the acceleration region is improved dramatically. Collimated GeV quasi-monoenergetic ion beams carrying as much as 19% of the laser energy are observed in multidimensional simulations.

CLONING OF THE FULL LENGTH PIGPIT1(POU1F1)CDNA AND A NOVEL ALTERNATIVEPIT1TRANSCRIPT, AND FUNCTIONAL STUDIES OF THEIR ENCODED PROTEINS

PIT1 is an essential regulatory gene of growth hormone (GH), prolactin (PRL) and thyrotropin beta subunit (TSHbeta). Previously, a partial pig PIT1 cDNA and a genomic clone of the entire 3' end of the PIT1 gene was isolated, and polymorphisms at PIT1 were associated with several performance traits in the pig. In order to understand the biological function of the pig PIT1 gene and its possible application in swine genetics, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to complete the cloning of the full length cDNA for pig PIT1. The pig PIT1 cDNA and its deduced protein sequence have approximately 90% and 95% identity, respectively, with the PIT1 cDNA and protein of other mammals (human, bovine, sheep and rodents). Surprisingly, sequence comparison to other pig PIT1 sequences indicated only approximately 93% identity. Additional sequencing confirmed our sequence, and identified a new polymorphism in exon 4. Phylogenetic analysis of several mammalian PIT1 sequences indicates sequencing errors may account for the discrepancies observed in the other pig sequences reported. Several PIT1 alternative spliced forms were also identified by RT-PCR. They were the delta3PIT1 (missing entire exon 3), delta4PIT1 (missing entire exon 4) and PIT1beta (additional 26 amino acids inserted in front of exon 2) transcripts. The delta4PIT1 and PIT1beta transcripts have been found to encode functionally different proteins in rodents. The delta3PIT1 transcript is a novel isoform of PIT1. Potentially different functions between pig delta3PIT1 and PIT1 were analyzed by expressing these proteins in bacteria. The E. coli-expressed PIT1 and delta3PIT1 proteins were used with rat growth hormone (rGH) and rat prolactin (rPRL) promoter DNA in DNA mobility shift assays. The results showed that pig PIT1 can specifically bind rGH and rPRL promoter regions, but that the pig delta3PIT1 cannot, even at very high protein concentrations. Possible protein-protein interactions between delta3PIT1 and PIT1 were tested by mixing protein extracts before the gel shift assay, and the results showed that delta3PIT1 protein did not affect PIT1 binding to its target DNA. These data demonstrate the functionality of the PIT1 cDNA cloned in this study, and identify a novel delta3PIT1 transcript which encodes a protein that cannot bind rGH/rPRL target sequences.

Genetic complementation to identify DNA elements that influence complement resistance in Leishmania chagasi

Past studies showed that Leishmania spp. promastigotes exhibit differential sensitivity to complement mediated lysis (CML) during development in vitro and in vivo. Leishmania chagasi promastigotes in cultures during logarithmic and stationary growth phases are CML-sensitive or CML-resistant when exposed to human serum, respectively, but only in cultures recently initiated with parasites from infected animals; serially passaged cultures become constitutively CML-sensitive regardless of growth phase. Building on these observations, a genetic screen was conducted to identify novel complement resistance factors of L. chagasi. A cosmid library containing genomic DNA was transfected into a promastigote line previously subjected to >50 serial passages. Selection with human serum for CML resistance yielded 12 transfectant clones. Cosmids isolated from 7 of these clones conferred CML resistance when transfected into an independent, high-passage promastigote culture; at 12% human serum, the mean survival of transfectants was 37% (+/- 11.6%), and that of control transfectants was about 1%. Inserts within the 7 cosmids were unique. Determination of the complete DNA sequence for 1 cosmid indicated that its 32-kilobase insert was 89% identical (overall) to a 31-kilobase region of Leishmania major chromosome 36, which is predicted to encode 6 genes, all of which encode hypothetical proteins.

Gamma-aminobutyric acid type A receptors modulate cAMP-mediated long-term potentiation and long-term depression at monosynaptic CA3-CA1 synapses

cAMP induces a protein-synthesis-dependent late phase of long-term potentiation (LTP) at CA3-CA1 synapses in acute hippocampal slices. Herein we report cAMP-mediated LTP and long-term depression (LTD) at monosynaptic CA3-CA1 cell pairs in organotypic hippocampal slice cultures. After bath application of the membrane-permeable cAMP analog adenosine 3',5'-cyclic monophosphorothioate, Sp isomer (Sp-cAMPS), synaptic transmission was enhanced for at least 2 h. Consistent with previous findings, the late phase of LTP requires activation of cAMP-dependent protein kinase A and protein synthesis. There is also an early phase of LTP induced by cAMP; the early phase depends on protein kinase A but, in contrast to the later phase, does not require protein synthesis. In addition, the cAMP-induced LTP is associated with a reduction of paired-pulse facilitation, suggesting that presynaptic modification may be involved. Furthermore, we found that Sp-cAMPS induced LTD in slices pretreated with picrotoxin, a gamma-aminobutyric acid type A (GABA(A)) receptor antagonist. This form of LTD depends on protein synthesis and protein phosphatase(s) and is accompanied by an increased ratio of failed synaptic transmission. These results suggest that GABA(A) receptors can modulate the effect of cAMP on synaptic transmission and thus determine the direction of synaptic plasticity.

A directed search for quantitative trait loci on chromosomes 4 and 7 in pigs

Improvements in the porcine genetic map and availability of resource families to study performance traits in pigs have made it possible to re-examine previous findings that linked certain traits to genes or chromosomal regions. Previous studies suggested that chromosomes 4 and 7 may be associated with growth and performance traits. To confirm these previous results, an interval mapping-regression approach was used to determine whether quantitative trait loci (QTL) exist in the Iowa State University reference/resource families. Traits measured were birth weight; body weight at 21 d; weaning weight (weight at 42 d); average daily gain; backfat at the first, 10th, lumbar, and last ribs and average backfat thickness; loin eye area; meat color; marbling; and firmness. The total number of F2 pigs used ranged from 241 to 330 and came from five Chinese x American resource families. Five markers (S0001, SW871, S0175, S0214, and SW445) were genotyped and mapped on chromosome 4, and so were 10 markers (S0064, tumor necrosis factor alpha [TNFalpha], S0102, S0078, S0158, S0066, SW304, SW1083, S0101, and S0212) on chromosome 7. Data were analyzed for each family (breed cross) separately and were also pooled. Experiment-wise thresholds were used to determine significance. Suggestive evidence of QTL on chromosomes 4 and 7 was observed for several traits in pooled and individual family analyses. Suggestive evidence of a QTL with a relatively large effect for average daily gain was detected on chromosome 4 in the pooled analysis. Significant (P < .05) evidence for QTL was seen on chromosome 7 for 10th-rib, last-rib, and average backfat thickness in the pooled data set in a region of the chromosome that was near TNFalpha. These results verify in part that chromosomes 4 and 7 contain QTL for growth and carcass traits.

Orphanin FQ/nociceptin inhibits synaptic transmission and long-term potentiation in rat dentate gyrus through postsynaptic mechanisms

Orphanin FQ/nociceptin (OFQ), a recently characterized natural ligand for the opioid receptor-like 1 (ORL1) receptor, shares structural similarity to the endogenous opioids. Our previous study found that OFQ, like classical opioids, modulated synaptic transmission and long-term potentiation (LTP) in the hippocampal CA1 region, suggesting a modulatory role for OFQ in synaptic plasticity involved in learning and memory. In the present study we investigated the action of OFQ in the dentate gyrus and explored possible underlying cellular mechanisms. Field potential recordings showed that OFQ significantly inhibited excitatory synaptic transmission and LTP induction in the dentate lateral perforant path. In the presence of OFQ, the excitatory postsynaptic potential (EPSP) slope-population spike (E-S) curve was shifted to the right, and no significant change was found in paired-pulse facilitation, suggesting a postsynaptic mechanism responsible for the inhibition of synaptic transmission. Under whole cell voltage-clamp conditions, bath application of OFQ activated K+ currents in most granule cells tested at a holding potential of -50 mV, suggesting that OFQ could reduce the excitability of dentate granule cells by hyperpolarizing cell membranes. OFQ also inhibited the amplitude of N-methyl-D-aspartate (NMDA) receptor-mediated excitatory postsynaptic currents (EPSCs) without affecting alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor-mediated EPSCs. This inhibition was not blocked by opioid receptor antagonists. Furthermore, the inward currents evoked by focal application of NMDA to granule cells were suppressed by OFQ in a dose-dependent manner, suggesting that OFQ may suppress LTP by inhibiting the function of postsynaptic NMDA receptors. These results demonstrate that OFQ may negatively modulate synaptic transmission and plasticity in the dentate gyrus through postsynaptic mechanisms, including hyperpolarization of granule cells as well as inhibition of the function of postsynaptic NMDA receptors/channels in dentate granule cells.

Orphanin FQ inhibits synaptic transmission and long-term potentiation in rat hippocampus

It is known that opioid peptides acting on opioid receptors can modulate hippocampal synaptic functions. Although a novel member of the opioid receptor family, ORL1 receptors, that displays high-sequence homology with classical opioid receptors is abundant in the hippocampus, little is known regarding its role in synaptic function. The present study was designed to investigate whether activation of the ORL1 receptor by its natural ligand, orphanin FQ, could modulate synaptic transmission and synaptic plasticity in the hippocampus. The actions of orphanin FQ in the CA1 and dentate gyrus were examined by field potential recordings in response to stimulation of Schaffer collaterals and perforant path, respectively. Our results showed that orphanin FQ, but not the inactive analog des-Phe1-orphanin FQ, reduced both the slope of the excitatory postsynaptic potentials and population spike amplitude. The inhibitory effect of orphanin FQ is dose dependent and probably involves a presynaptic mechanism, as suggested by the significantly increased paired-pulse facilitation evoked in the presence of orphanin FQ. In addition, orphanin FQ was found to inhibit the induction of long-term potentiation at the Schaffer collateral-CA1 synapse. These results demonstrate that orphanin FQ can function as an inhibitory modulator regulating synaptic transmission and synaptic plasticity in the hippocampus, suggesting that activation of ORL1 receptors may play an important role in synaptic plasticity involved in learning and memory.

Association of PIT1 polymorphisms with growth and carcass traits in pigs

PIT1, a member of the POU-domain family of genes, is a positive regulatory factor of growth hormone, prolactin, and thyrotroph-stimulating hormone beta in several mammals. Therefore, PIT1 was chosen as a candidate gene to investigate its association with growth and carcass traits in pigs. The five Iowa State University reference/resource three-generation families consisting of crosses of Meishan x Duroc, Meishan x Hampshire, Meishan x Landrace, Minzhu x Hampshire, and Minzhu x Landrace were used. The three PIT1 polymorphisms were based on two RFLP using a PIT1 POU-domain cDNA probe and the restriction enzymes BamHI and MspI and a PCR/RFLP using RsaI. Birth, 21-d, and 42-d weights, average daily gain, several backfat measurements, longissimus muscle area, muscle color, marbling, and firmness scores were evaluated for their association with the three PIT1 polymorphisms. Mixed-animal-model analyses were used with the informative family data in which the PIT1 polymorphisms were segregating. Results from mixed-model analyses revealed that pigs with the MspI CC genotype (P < .01) were associated with heavier birth weight (.12 kg) than DD genotype pigs. The MspI CC genotype pigs were also significantly associated with greater average backfat (.41 cm, P < .01), greater first-rib backfat (.45 cm, P < .01), greater last-rib backfat (.32 cm, P < .07), and greater last lumbar backfat (.46 cm, P < .10) than the DD genotype pigs. The CC genotype represents primarily Chinese alleles and may be useful for future genetic improvement in synthetic lines involving Chinese and American pigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Three-dimensional quantification of mossy-fiber presynaptic boutons in living hippocampal slices using confocal microscopy

Confocal laser scanning microscopy (CLSM) was used to visualize presynaptic elements of mossy-fiber synapses in living rat hippocampal slices. Mossy fiber (mf) axons and their boutons were labeled in transverse hippocampal slices by injecting one of three fluorescent dyes (diI, diA, or fast diI) into stratum granulosum of the dentate gyrus and/or stratum lucidum of CA3. Three-dimensional (3D) images of the mf boutons were obtained from serial optical sections in stratum lucidum. The 3D data were used to quantify and characterize the size and shape of the boutons based on their volumes (V) and surface areas (A), and the latter were compared with conventional 2D analyses. Various geometric models were fitted to the V-A relationship, one of which provided a reasonable approximation to the data. The results demonstrate that this approach is useful for quantifying and characterizing the size and shape of mf expansions and raise the possibility of detecting and analyzing in real time activity-dependent modifications in presynaptic structure.

Expression pattern, genomic cloning and RFLP analyses of the swine PIT-1 gene

The swine PIT-1 POU domain cDNA was used to study PIT-1 expression and to clone the PIT-1 genomic region to identify additional PIT-1 polymorphisms. PIT-1 was expressed only in the pituitary, confirming the swine cDNA identity. To study the PIT-1 genomic region, a clone containing 13.7 kb DNA was isolated. EcoRI fragments hybridizing to PIT-1 were sequenced, and the 3' portion of PIT-1 gene identified. Primers for polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis were then designed. Restriction analysis of PCR products identified a RsaI RFLP. In contrast to other PIT-1 RFLPs, the RsaI PCR-RFLP was widely distributed in American breeds. Thus, the RsaI RFLP and the previously reported PIT-1 RFLPs allow detection of PIT-1 alleles in most, if not all, breeds currently used in the US and European reference/resource pig mapping families.

Cloning and restriction fragment length polymorphism analysis of a cDNA for swine PIT-1, a gene controlling growth hormone expression

A partial swine cDNA which encodes the functional domain of PIT-1 was isolated by the polymerase chain reaction (PCR). The swine PIT-1 cDNA clone is 95% identical at the protein level to the rat Pit-1 gene. Thus, Pit-1's known function in control of rat growth hormone and prolactin expression is likely to be conserved in swine. This swine cDNA clone was used to investigate genetic variability at PIT-1 in several American and Chinese breeds. Polymorphic BamHI fragments were found in pure-bred Meishan animals (n = 13), but only monomorphic fragments in five American breeds (n = 36).