Patch-Clamp Analysis of Voltage-Activated and Chemically Activated Currents in the Vomeronasal Organ Of Sternotherus Odoratus (Stinkpot/Musk Turtle)

The electrophysiological basis of chemical communication in the specialized olfactory division of the vomeronasal (VN) organ is poorly understood. In total, 198 patch-clamp recordings were made from 42 animals (Sternotherus odoratus, the stinkpot/musk turtle) to study the electrically and chemically activated properties of VN neurons. The introduction of tetramethylrhodamine-conjugated dextran into the VN orifice permitted good visualization of the vomeronasal neural epithelium prior to dissociating it into single neurons. Basic electrical properties of the neurons were measured (resting potential, -54.5 +/- 2.7 mV, N=11; input resistance, 6.7 +/- 1.4 G Omega, N=25; capacitance, 4.2 +/- 0.3 pF, N=22; means +/- S.E.M.). The voltage-gated K(+) current inactivation rate was significantly slower in VN neurons from males than in those from females, and K(+) currents in males were less sensitive (greater K(i)) to tetraethylammonium. Vomeronasal neurons were held at a holding potential of -60 mV and tested for their response to five natural chemicals, female urine, male urine, female musk, male musk and catfish extract. Of the 90 VN neurons tested, 33 (34 %) responded to at least one of the five compounds. The peak amplitude of chemically evoked currents ranged from 4 to 180 pA, with two-thirds of responses less than 25 pA. Urine-evoked currents were of either polarity, whereas musk and catfish extract always elicited only inward currents. Urine applied to neurons harvested from female animals evoked currents that were 2-3 times larger than those elicited from male neurons. Musk-evoked inward currents were three times the magnitude of urine- or catfish-extract-evoked inward currents. The calculated breadth of responsiveness for neurons presented with this array of five chemicals indicated that the mean response spectrum of the VN neurons is narrow (H metric 0.11). This patch-clamp study indicates that VN neurons exhibit sexual dimorphism in function and specificity in response to complex natural chemicals.io

Surface morphology of AlGaN/GaN heterostructures grown on bulk GaN by MBE

In this report the influence of the growth conditions on the surface morphology of AlGaN/GaN heterostructures grown on sapphire-based and bulk GaN substrates is nondestructively investigated with focus on the decoration of defects and the surface roughness. Under Ga-rich conditions specific types of dislocations are unintentionally decorated with shallow hillocks. In contrast, under Ga-lean conditions deep pits are inherently formed at these defect sites. The structural data show that the dislocation density of the substrate sets the limit for the density of dislocation-mediated surface structures after MBE overgrowth and no noticeable amount of surface defects is introduced during the MBE procedure. Moreover, the transfer of crystallographic information, e.g. the miscut of the substrate to the overgrown structure, is confirmed. The combination of our MBE overgrowth with the employed surface morphology analysis by atomic force microscopy (AFM) provides a unique possibility for a nondestructive, retrospective analysis of the original substrate defect density prior to device processing

Understanding the evolution of native pinewoods in Scotland will benefit their future management and conservation

Scots pine (Pinus sylvestris L.) is a foundation species in Scottish highland forests and a national icon. Due to heavy exploitation, the current native pinewood coverage represents a small fraction of the postglacial maximum. To reverse this decline, various schemes have been initiated to promote planting of new and expansion of old pinewoods. This includes the designation of seed zones for control of the remaining genetic resources. The zoning was based mainly on biochemical similarity among pinewoods but, by definition, neutral molecular markers do not reflect local phenotypic adaptation. Environmental variation within Scotland is substantial and it is not yet clear to what extent this has shaped patterns of adaptive differentiation among Scottish populations. Systematic, rangewide common-environment trials can provide insights into the evolution of the native pinewoods, indicating how environment has influenced phenotypic variation and how variation is maintained. Careful design of such experiments can also provide data on the history and connectivity among populations, by molecular marker analysis. Together, phenotypic and molecular datasets from such trials can provide a robust basis for refining seed transfer guidelines for Scots pine in Scotland and should form the scientific basis for conservation action on this nationally important habitat

Dose homogeneity in the group of 15 patients undergoing fractionated total body irradiation

MethodsFractionated total body irradiation (FTBI) before bone marrow transplantation (BMT) was performed in 15 patients with different proliferative diseases.Common regimen of 12 Gy in 8 fractions (four days) was applied with the reduction of dose to lungs to 9.4 Gy.ResultsMidline dose discrepancies ranged from −15.9% to +9.9% and exceeded ±10% of prescribed dose in one patient. Outside midline dose discrepancies ranged from −16.5% to +19.8% and exceeded ±10% of prescribed dose in six patients.Dose determination error was estimated for between 2.8% and 5% depending on the body part.ConclusionsEstimated error of the dose determination increased dose deviations from prescribed values from between −1.6% and +4.8% to between −5.2% and +9.3% in midline and from −8.4% and +19.8% to between −12.0% and +24.8% across transverses

32 Porównanie rozkładu dawek w ciele chorego podczas napromienianiania całego ciała w technice radioterapiiCo-60 i akceleratorem X 15 MeV

Napromienianie całego ciała stosuje się w procesie leczenia chorych na niektóre nowotwory układu krwiotwórczego. Celem napromieniania jest wytrzebienie komórek nowotworowych rozsianych na całym ciele, wywołanie immunosupresji i przygotowanie miejsca pod nowo przeszczepiony szpik.MetodaNapromieniano dwudziestu chorych przy użyciu aparatu kobaltowego Co-60 i sześciu przy użyciu akceleratora X 15 MeV. Zastosowano pola boczne i przednio –tylne (AP/PA). W polach AP/PA stosowano osłony płuc. Łączna dawka wynosiła 12,6 Gy w całym ciele i 9 Gy w płucach. Ścianę klatki piersiowej w obu przypadkach dopromieniano elektronami o energii 6 MeV–10 MeV.Do pomiarów dawki in vivo zastosowano detektory termoluminescencyjne i półprzewodnikowe rozmieszczone w 10 przekrojach referencyjnych na wejściu i wyjsciu promieniowania do i z ciała.WynikiNiejednorodność dawki w przypadku stosowania promieniowania Co-60 wynosiła od −0,8% do +7,9% w linii środkowej ciała i od 0,5% do +5,8 dla promieniowania X 15 MV. Odpowiednio poza linią środkową ciała od −1,6% do +8,7% dla Co-60 i od −1,2% do +6,9% dla X 15 MeV.Wnioski-zastosowanie promieniowania X 15 MeV zmniejszyło niejednorodność dawki w całym ciele do −1,2%÷ +6,9%-zastosowanie promieniowania X 15 MeV skróciło czas napromieniania poprzez eliminację konieczności obracania chorego podczas pól AP/PA oraz przenoszenia chorego na drugi aparat (akcelerator) w celu dopromienienia ciała elektronami

Substantial heritable variation for susceptibility to Dothistroma septosporum within populations of native British Scots pine (Pinus sylvestris)

The threat from pests and pathogens to native and commercially planted forest trees is unprecedented and expected to increase under climate change. The degree to which forests respond to threats from pathogens depends on their adaptive capacity, which is determined largely by genetically controlled variation in susceptibility of the individual trees within them and the heritability and evolvability of this trait. The most significant current threat to the economically and ecologically important species Scots pine (Pinus sylvestris) is dothistroma needle blight (DNB), caused by the foliar pathogen Dothistroma septosporum. A progeny-population trial of 4-year-old Scots pine trees, comprising six populations from native Caledonian pinewoods each with three to five families in seven blocks, was artificially inoculated using a single isolate of D. septosporum. Susceptibility to D. septosporum, assessed as the percentage of non-green needles, was measured regularly over a period of 61 days following inoculation, during which plants were maintained in conditions ideal for DNB development (warm; high humidity; high leaf wetness). There were significant differences in susceptibility to D. septosporum among families indicating that variation in this trait is heritable, with high estimates of narrow-sense heritability (0.38–0.75) and evolvability (genetic coefficient of variation, 23.47). It is concluded that native Scots pine populations contain sufficient genetic diversity to evolve lower susceptibility to D. septosporum through natural selection in response to increased prevalence of this pathogen

Early post-BMT liver function in children conditioned for bone marrow transplantation with busulfan-containing and with hyperfractionated TBI-containing preparative regimens

Liver toxicity following preparatory regimen (prep-reg) for bone marrow transplantation (BMT) creates one of the major problems in the early post-BMT period, especially in patients (pts.) with pretransplant HCV and/or HBV infections, and liver dysfunction. This gave rise to the search for prep-reg, that would be less hepatotoxic, but would still have sufficient antileukemic effect. Therefore, we compared liver function in children prepared for allo-BMT with busulfan-containing and with hyperfractionated TBI-containing regimens.Patients and methodsSeventeen pts. have been conditioned with busulfan-containing prep-reg (10 with BuVpCy, 7 with BuCy) (Bu-group). Diagnosis consisted of ALL (6) and AML (11). All pts. fram Bu-group have been transplanted with bone marrow from HLA-identical, MLC non-reactive siblings. Pretransplant screening showed positive HBsAg in one patient, and HCV antibody in 6 pts. For GvHD prevention CsA+MTX have been given in 12 pts., CsA+MTX+PRED in 3 pts., and CsA alone in 2 pts. Acute GvHD II- IVO occured in 4 pts. Hyperfractionated TBI (hFTBI) (2 × 1,5 Gy on 4 consecutive days) was employed in 10 pts. (hFTBI+Cy in 6 pts., hFTBI+Vp in 4 pts.) (hFTBI-group). Nine pts. were transplanted for ALL, and one child for AML. Nine pts. from hFTBI-graup have been transplanted with bone marraw fram HLA-identical, MLC non-reactive siblings, and one child from a syngeneic twin. For GvHD prevention 5 pts. have been treated with CsA+MTX, 2 with CsA+PRED, and 2 with CsA alone (recipient of syngeneic bone marrow received no GvHD prophylaxis). Acute GvHD IIO was observed in one child. For HVOD prevention in all children from both groups continuous infusion of alprostadil and/or low-dose heparin (100 units/kg/day) has been administered. Total bilirubine concentration, alanine aminotransferase (AIAt) and aspartate aminotransferase (AspAt) activity were measured in serum on day −10, −1, +7, +14, +21, +28 and +35 by automated chemical analysis using standard reagents.ResultsOne child (AML, pos. HCV antibody, BuCy, CsA alone for GvHD prevention) from Bu-group developed on day +18 day recurrent form of severe HVOD leading to the death on day +102.ConclusionsAccording to liver function parameters observed till day +35 post-BMT, ie. during the period, when the risk of HVOD is highest, hFTBI seems to be less hepatotoxic than busulfan-containing prep-reg. Therefore BM-recipients with liver dysfunction observed prior to BMT should rather be prepared for transplantation with hFTBI

28. Comparison of doses measured by thermolumi-nescent and semiconductor detectors during total body irradiation at Cobalt-60 and 15 meV linear accelerator

In-vivo dosimetry is an important way of dose verification during total body irradiation (TBI).AimThe aim of this paper was to compare the doses measured in-vivo with two types of detectors: thermoluminescent (TLD) and semiconductor (SEM) during TBI.PatientsSince 1993, 38 patients have TBI performed, out of them – 22 on Cobalt-60 and 16 on 15 MeV linear accelerator. Total dose of 12,6 Gy was prescribed and delivered in 8 fractions during 4 days. Combination of lateral and anterior-posterior fields, with lung shields was used. Doses were measured with the aim to verify primarily calculated doses (in ten reference points in the body).MethodsMeasured doses were normalised to those pre-calculated. Mean doses and their standard deviations (SD) were calculated separately for each of ten sections, for doses measured with TLD and SEM detectors respectively. Analysis was carried out for doses measured in points lying on the beam to the body entry during irradiation at lateral fields.ResultsMean dose for the whole group of patients treated on Cobalt-60, for all ten sections together, measured with TLD detectors was equal to 1,05 (normalised to calculated dose) with standard deviation (SD) of 3,4% and for SEM was equal to 0,98 with SD = 2,5%. Respectively, for 15 MeV linear accelerator mean dose for TLD was 1,05 with SD = 3,1% and 1,02 with SD = 3,1%.ConclusionsMean differences between doses measured with TLD and SEM dosimeters at beam entry at lateral fields were equal to 6,8% for Cobalt-60 and 3,1% for 15 MeV

47. Allogeneic bone marrow transplantation in children with acute lymphoblastic leukemia in first and second complete remission conditioned with fractionated total body irradiation and etoposide or cyclophosphamide

Patients and methodsFrom 1993 to 2001 thirty two children underwent bone marrow transplantation (BMT) for ALL (12 in I CR and 20 in II CR after early BM or BM/organ relapse). Except 2 syngeneic all other were HLA-identical siblings transplants. All patients (pts) were conditioned with FTBI 2×1,5 Gy for 4 days (total dose 12 Gy) with lung shielding (9 Gy) and CY 60 mg/kg i.v for 2 days (total dose 120 mg/kg) (n=1 in I CR and n = 11 in II CR) or VP 60 mg/kg i.v (n = 11 in I CR and n = 9 in II CR), Pts in I CR have been given 1,1–4,9×108 MNC/kg (med. 2,7×108/kg), while pts in II CR 1,9–4,0×108 MNC/kg (med. 2,7×108/kg). For GvHD prevention CsA 3 mg/kg/d i.v was administered alone in 22 pts (n = 9 in I CR and n = 13 in II CR) or in combination with “short” MTX +/− PRED in 8 pts (n = 3 in I CR and n = 5 in II CR). Two pts transplanted with syngeneic BM received no GvHD prevention. Regimen related toxicity (RRT) was graded according to the system developed by Bearman et al. (1988).ResultsOnly mild or moderate expression of RRT was observed (GI toxicity, I°− 80%, II° −4%; stomatitis I° −40%, II° −20%; hepatic toxicity I°− 28%; renal, bladder and cardiac toxicity I°− 4%) and no transplant related deaths occured (TRM=0%). Among 12 pts transplanted in I CR only one child relapsed 4 months from BMT, while remaining 11 pts are alive in CCR with a median follow-up of 33months (range 6 to 66 months) and 92% probability of 5-year EFS. Of 20 children transplanted in II CR 6 relapsed 1–14 months from BMT (median 6,5 months). Fourteen of them remain in CCR with a median follow-up 19,5 months (range 1 to 96 months) and 66% probability of 8-year EFS.Conclusions1.In children with ALL the FTBI-12 Gy-containing regimen is well tolerated without the life-threatening toxic complications.2.FTBI-12 Gy-containing regimen demonstrates very good antileukemic efficacy for HR-ALL in I CR, but only limited for ALL in II CA.3.3. In context of good tolerance of FTBI in a total dose of 12 Gy and its limited antileukemic efficacy in children with ALL in II CR the escalation of FTBI total dose from 12 Gy to 13,2 Gy appears to be justified in those children. Supported by grant KBN 4 PO5E 108 18

Response of electrically coupled spiking neurons: a cellular automaton approach

Experimental data suggest that some classes of spiking neurons in the first layers of sensory systems are electrically coupled via gap junctions or ephaptic interactions. When the electrical coupling is removed, the response function (firing rate {\it vs.} stimulus intensity) of the uncoupled neurons typically shows a decrease in dynamic range and sensitivity. In order to assess the effect of electrical coupling in the sensory periphery, we calculate the response to a Poisson stimulus of a chain of excitable neurons modeled by $n$-state Greenberg-Hastings cellular automata in two approximation levels. The single-site mean field approximation is shown to give poor results, failing to predict the absorbing state of the lattice, while the results for the pair approximation are in good agreement with computer simulations in the whole stimulus range. In particular, the dynamic range is substantially enlarged due to the propagation of excitable waves, which suggests a functional role for lateral electrical coupling. For probabilistic spike propagation the Hill exponent of the response function is $\alpha=1$, while for deterministic spike propagation we obtain $\alpha=1/2$, which is close to the experimental values of the psychophysical Stevens exponents for odor and light intensities. Our calculations are in qualitative agreement with experimental response functions of ganglion cells in the mammalian retina.Comment: 11 pages, 8 figures, to appear in the Phys. Rev.