Edge State, Band Topology, and Time Boundary Effect in the Fine-Grained Categorization of Chern Insulators

We predict novel topological phases with broken time-reversal symmetry supporting the coexistence of opposite chiral edge states, which are fundamentally different from the photonic spin-Hall, valley-Hall, and higher-order topological phases. We find a fine-grained categorization of Chern insulators, their band topologies characterized by identical Chern numbers are completely different. Furthermore, we prove that different topologies cause zeros in their Bloch wave function overlaps, which imprint the band gap closing and appear at the degenerate points of topological phase transition. The Bloch wave function overlaps predict the reflection and refraction at a topological time boundary, and the overlap zeros ensure the existence of vanishing revival amplitude at critical times even though different topologies before and after the time boundary have identical Chern numbers. Our findings create new opportunities for topological metamaterials, uncover the topological feature hidden in the time boundary effect as a probe of topology, and open a venue for the exploration of the rich physics originating from the long-range couplings.

Discovery of New Isotopes ^{160}Os and ^{156}W: Revealing Enhanced Stability of the N=82 Shell Closure on the Neutron-Deficient Side

Using the fusion-evaporation reaction ^{106}Cd(^{58}Ni,4n)^{160}Os and the gas-filled recoil separator SHANS, two new isotopes _{76}^{160}Os and _{74}^{156}W have been identified. The α decay of ^{160}Os, measured with an α-particle energy of 7080(26) keV and a half-life of 201_{-37}^{+58}  μs, is assigned to originate from the ground state. The daughter nucleus ^{156}W is a β^{+} emitter with a half-life of 291_{-61}^{+86}  ms. The newly measured α-decay data allow us to derive α-decay reduced widths (δ^{2}) for the N=84 isotones up to osmium (Z=76), which are found to decrease with increasing atomic number above Z=68. The reduction of δ^{2} is interpreted as evidence for the strengthening of the N=82 shell closure toward the proton drip line, supported by the increase of the neutron-shell gaps predicted in theoretical models.

[Efficacy and outcomes of shunt surgery for secondary hydrocephalus]

Records of secondary hydrocephalus patients undergoing shunt surgery in the Department of Neurosurgery of Peking Union Medical College Hospital from September 2012 to April 2022 and their clinical characteristics and outcomes were retrospectively reviewed and analyzed. Among 121 patients who received first time shunt placement, the most common causes of secondary hydrocephalus were brain hemorrhage (55, 45.5%) and trauma (35, 28.9%). Cognition decline (106, 87.6%), abnormal gait (50, 41.3%) and incontinence (40, 33.1%) were the most prevalent manifestations. Postoperative central nervous system infection (4, 3.3%), shunt obstruction (3, 2.5%) and subdural hematoma/effusion (4, 3.3%) were the most frequent neurological complications. Overall incidence of postoperative complications was 9% (11 cases) in the current cohort. And 50.5% (54/107) of the patients receiving shunting achieved a Glasgow outcome scale (GOS) score of at least 4. Shunt surgery is preferred for secondary hydrocephalus, especially for secondary normal pressure hydrocephalus. Moreover, it is recommended to complete cranioplasty in staged operation or one-stage operation for the patients with decompressive craniectomy.

Mass Measurement of Upper fp-Shell N=Z-2 and N=Z-1 Nuclei and the Importance of Three-Nucleon Force along the N=Z Line

Using a novel method of isochronous mass spectrometry, the masses of ^{62}Ge, ^{64}As, ^{66}Se, and ^{70}Kr are measured for the first time, and the masses of ^{58}Zn, ^{61}Ga, ^{63}Ge, ^{65}As, ^{67}Se, ^{71}Kr, and ^{75}Sr are redetermined with improved accuracy. The new masses allow us to derive residual proton-neutron interactions (δV_{pn}) in the N=Z nuclei, which are found to decrease (increase) with increasing mass A for even-even (odd-odd) nuclei beyond Z=28. This bifurcation of δV_{pn} cannot be reproduced by the available mass models, nor is it consistent with expectations of a pseudo-SU(4) symmetry restoration in the fp shell. We performed ab initio calculations with a chiral three-nucleon force (3NF) included, which indicate the enhancement of the T=1 pn pairing over the T=0 pn pairing in this mass region, leading to the opposite evolving trends of δV_{pn} in even-even and odd-odd nuclei.

Observation of a Strongly Isospin-Mixed Doublet in ^{26}Si via β-Delayed Two-Proton Decay of ^{26}P

β decay of proton-rich nuclei plays an important role in exploring isospin mixing. The β decay of ^{26}P at the proton drip line is studied using double-sided silicon strip detectors operating in conjunction with high-purity germanium detectors. The T=2 isobaric analog state (IAS) at 13 055 keV and two new high-lying states at 13 380 and 11 912 keV in ^{26}Si are unambiguously identified through β-delayed two-proton emission (β2p). Angular correlations of two protons emitted from ^{26}Si excited states populated by ^{26}P β decay are measured, which suggests that the two protons are emitted mainly sequentially. We report the first observation of a strongly isospin-mixed doublet that deexcites mainly via two-proton decay. The isospin mixing matrix element between the ^{26}Si IAS and the nearby 13 380-keV state is determined to be 130(21) keV, and this result represents the strongest mixing, highest excitation energy, and largest level spacing of a doublet ever observed in β-decay experiments.

Direct Measurement of the Astrophysical ^{19}F(p,αγ)^{16}O Reaction in the Deepest Operational Underground Laboratory

Fluorine is one of the most interesting elements in nuclear astrophysics, where the ^{19}F(p,α)^{16}O reaction is of crucial importance for Galactic ^{19}F abundances and CNO cycle loss in first generation Population III stars. As a day-one campaign at the Jinping Underground Nuclear Astrophysics experimental facility, we report direct measurements of the essential ^{19}F(p,αγ)^{16}O reaction channel. The γ-ray yields were measured over E_{c.m.}=72.4-344  keV, covering the Gamow window; our energy of 72.4 keV is unprecedentedly low, reported here for the first time. The experiment was performed under the extremely low cosmic-ray-induced background environment of the China JinPing Underground Laboratory, one of the deepest underground laboratories in the world. The present low-energy S factors deviate significantly from previous theoretical predictions, and the uncertainties are significantly reduced. The thermonuclear ^{19}F(p,αγ)^{16}O reaction rate has been determined directly at the relevant astrophysical energies.

New α-Emitting Isotope ^{214}U and Abnormal Enhancement of α-Particle Clustering in Lightest Uranium Isotopes

A new α-emitting isotope ^{214}U, produced by the fusion-evaporation reaction ^{182}W(^{36}Ar,4n)^{214}U, was identified by employing the gas-filled recoil separator SHANS and the recoil-α correlation technique. More precise α-decay properties of even-even nuclei ^{216,218}U were also measured in the reactions of ^{40}Ar, ^{40}Ca beams with ^{180,182,184}W targets. By combining the experimental data, improved α-decay reduced widths δ^{2} for the even-even Po-Pu nuclei in the vicinity of the magic neutron number N=126 are deduced. Their systematic trends are discussed in terms of the N_{p}N_{n} scheme in order to study the influence of proton-neutron interaction on α decay in this region of nuclei. It is strikingly found that the reduced widths of ^{214,216}U are significantly enhanced by a factor of two as compared with the N_{p}N_{n} systematics for the 84≤Z≤90 and N<126 even-even nuclei. The abnormal enhancement is interpreted by the strong monopole interaction between the valence protons and neutrons occupying the π1f_{7/2} and ν1f_{5/2} spin-orbit partner orbits, which is supported by the large-scale shell model calculation.

Short-Lived α-Emitting Isotope ^{222}Np and the Stability of the N=126 Magic Shell

A new, very short-lived neutron-deficient isotope ^{222}Np was produced in the complete-fusion reaction ^{187}Re(^{40}Ar,5n)^{222}Np, and observed at the gas-filled recoil separator SHANS. The new isotope ^{222}Np was identified by employing a recoil-α correlation measurement, and six α-decay chains were established for it. The decay properties of ^{222}Np with E_{α}=10016(33)  keV and T_{1/2}=380_{-110}^{+260}  ns were determined experimentally. The α-decay systematics of Np isotopes is improved by adding the new data for ^{222}Np, which validates the N=126 shell effect in Np isotopes. The evolution of the N=126 shell closure is discussed in the neutron-deficient nuclei up to Np within the framework of α-decay reduced width.

New Isotope ^{220}Np: Probing the Robustness of the N=126 Shell Closure in Neptunium

A new short-lived neutron-deficient isotope ^{220}Np was synthesized in the fusion-evaporation reaction ^{185}Re(^{40}Ar,5n)^{220}Np at the gas-filled recoil separator SHANS. Based on the measurement of the correlated α-decay chains, the decay properties of ^{220}Np with E_{α}=10040(18)  keV and T_{1/2}=25_{-7}^{+14}  μs were determined, which are in good agreement with theoretical predictions. From the new experimental results coupled with the recently reported α-decay data of ^{219,223}Np, the α-decay systematics for Np isotopes around N=126 was established, which allows us for the first time to test the robustness of the N=126 shell closure in Z=93 Np isotopes. The results also indicate that, in the region of nuclei with Z≥83, the proton drip line has been reached for all odd-Z isotopes up to Np.

[Diagnostic values of BRAF(V600E) mutation analysis and Bethesda system for reporting thyroid cytopathology in thyroid nodules with TIRADS 4 and 5]

Objective: To evaluate the diagnostic efficacies of BRAF(V600E) testing and Bethesda system for reporting thyroid cytopathology (BSRTC) in thyroid nodules with thyroid imaging reporting and data system (TIRADS) category 4 and 5. Methods: A total of 187 thyroid nodules in 187 patients underwent the examinations of ultrasound-guided fine needle aspiration cytology (FNAC) and BRAF(V600E) mutation were analyzed retrospectively. Receive operating characteristic (ROC) curve was used to investigate the diagnostic values of both methods and the clinical application of BRAF(V600E) combined with BSRTC was evaluated. SPSS17.0 software was used to analyze the data. Results: Among 187 thyroid nodules, 123 were malignant nodules confirmed with histopathological examination and 64 benign nodules determined by FNAC, histopathological examination, or long-term follow-up. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of BRAF(V600E) test were better than those of BSRTC [69.1%, 98.4%, 98.8%, 62.4%(χ(2)=77.3, P=0.000) vs 62.6%, 93.8%, 95.1%, 56.6%(χ(2)=54.4, P=0.000)]. While the sensitivity, specificity, PPV and NPV of the combined test of BRAF(V600E) and BSRTC for diagnosis of malignant thyroid nodules were 87.8%, 92.2%, 95.6%, 79.7%(χ(2)=112.6, P=0.000), respectively. The area under the ROC curve for the combined test was higher than that for each of tests (0.900 vs 0.858 or 0.838). Conclusions: The combined test of BRAF(V600E) mutation and BSRTC has a higher diagnostic efficacy for malignant thyroid nodules compared with BRAF(V600E) mutation or BSRTC alone.

[Prediction of occult carcinoma in contralateral nodules based on the ultrasonic features of unilateral papillary thyroid carcinoma]

Objective: To investigate the occurrence of occult carcinoma in contralateral lobes based on the ultrasonic features of unilateral papillary thyroid carcinoma. Methods: The study included 202 consecutives cases of unilateral papillary thyroid carcinoma with benign nodules in the contralateral lobe identified by preoperative ultrasound or fine-needle aspiration from June 2014 to December 2015. All patients received total thyroidectomies, and with postoperative pathological examination they were divided into two groups, one including 60 cases with positive occult cancer and another one consisting of 142 cases with negative occult cancer. Univariate and multivariate analyses were performed to analyze the sonographic features of unilateral papillary thyroid carcinoma relevant to the occurrence of occult carcinoma in the contralateral nodules. Results: Univariate analysis indicated occult carcinoma in the contralateral lobes was associated with Hashimoto's thyroiditis(χ(2)=3.955, P=0.047), unclear border (χ(2)=4.375, P=0.036)and multifocality in the ipsilateral(χ(2)=7.375, P=0.007), but not with tumors maximum size, location, A/T, shape, internal structure, internal echo, acoustic halo, calcification, capsular invasion and blood flow signal in the lobe with carcinoma on another side. Multivariate analysis showed unclear border (OR=2.727, P=0.010) and multifocality in the ipsilateral(OR=2.807, P=0.005)of carcinoma were independent predictive factor for contralateral occult PTC. Conclusions: Unclear border and multifocality of PTC in the ipsilateral were closely relevant to the occurrence of occult carcinoma in the contralateral nodules.

Identification of the Lowest T=2, J^{π}=0^{+} Isobaric Analog State in ^{52}Co and Its Impact on the Understanding of β-Decay Properties of ^{52}Ni

Masses of ^{52g,52m}Co were measured for the first time with an accuracy of ∼10  keV, an unprecedented precision reached for short-lived nuclei in the isochronous mass spectrometry. Combining our results with the previous β-γ measurements of ^{52}Ni, the T=2, J^{π}=0^{+} isobaric analog state (IAS) in ^{52}Co was newly assigned, questioning the conventional identification of IASs from the β-delayed proton emissions. Using our energy of the IAS in ^{52}Co, the masses of the T=2 multiplet fit well into the isobaric multiplet mass equation. We find that the IAS in ^{52}Co decays predominantly via γ transitions while the proton emission is negligibly small. According to our large-scale shell model calculations, this phenomenon has been interpreted to be due to very low isospin mixing in the IAS.

Sheep YAP1 temporal and spatial expression trend and its relation with MyHCs expression

RT-PCR was used to study the temporal and spatial pattern of Yes-associated protein 1 (YAP1) and myosin heavy chain (MyHC) expression in four different skeletal muscles (i.e., longissimus dorsi muscle, soleus muscle, gastrocnemius muscle, and extensor digitorum longus) and three growth stages (i.e., 2 days old, 2 and 6 months old) of Hu Sheep. The results showed that YAP1 was differentially expressed in skeletal muscles of sheep, that expression increased gradually with age, and that there were high levels of expression in the gastrocnemius muscle and lower levels in the longissimus dorsi muscle. MyHCI was expressed at high levels in the soleus muscle and at lower levels in the longissimus dorsi muscle. In contrast, MyHCIIA and MyHCIIX were expressed at high levels in the extensor digitorum longus and at lower levels in the soleus muscle. The expression of MyHCI and MyHCIIA decreased with increasing age while that of MyHCIIX increased. YAP1 expression was negatively correlated with MyHCII (P < 0.01) and positively correlated with MyHCIIX (P < 0.01) across all growth stages and skeletal muscle types studied. We speculate that after birth, the thicker muscle fiber diameter is associated with the high expression of MyHCIIX. Therefore, we conclude that YAP1 expression affects sheep muscle fiber development after birth and provides important genetic information for the selection candidate genes for sheep muscle growth.

Thermal conductivity of the diamond-chain compound Cu₃(CO₃)₂(OH)₂

Thermal conductivity (κ) of a distorted spin diamond-chain system, Cu3(CO3)2(OH)2, is studied at low temperatures down to 0.3 K and in magnetic fields up to 14 T. In zero field, the κ(T) curve with heat current along the chain direction has very small magnitudes and shows a pronounced three-peak structure. The magnetic fields along and perpendicular to the chains change the κ strongly in a way having good correspondence to the changes of magnetic specific heat in fields. The data analysis based on the Debye model for phononic thermal conductivity indicates that the heat transport is due to phonons and the three-peak structure is caused by two resonant scattering processes by the magnetic excitations. In particular, the spin excitations of the chain subsystem are strongly scattering phonons rather than transporting heat.

A simple scheme for injection and extraction in compact rings

There has been great interest in building compact synchrotrons for various applications, for example, inverse Compton scattering X-ray sources. However, the beam injection and extraction in compact rings require careful design for the lack of space. In this paper, we propose a simple combined injection-extraction scheme exploiting the fringe field of existing dipole magnets instead of additional septum magnets. This scheme is illustrated by using the 4.8 m ring proposed for Tsinghua Thomson scattering X-ray source as an example. Particle tracking is applied to demonstrate the validity of this scheme.

Mass measurements of the neutron-deficient 41Ti, 45Cr, 49Fe, and 53Ni nuclides: first test of the isobaric multiplet mass equation in f p-shell nuclei

Isochronous mass spectrometry has been applied to neutron-deficient 58Ni projectile fragments at the HIRFL-CSR facility in Lanzhou, China. Masses of a series of short-lived T(z)=-3/2 nuclides including 41Ti, 45Cr, 49Fe, and 53Ni have been measured with a precision of 20-40 keV. The new data enable us to test for the first time the isobaric multiplet mass equation (IMME) in fp-shell nuclei. We observe that the IMME is inconsistent with the generally accepted quadratic form for the A=53, T=3/2 quartet. We perform full space shell model calculations and compare them with the new experimental results.

Direct mass measurements of short-lived A=2Z-1 nuclides (63)Ge, (65)As, (67)Se, and (71)Kr and their impact on nucleosynthesis in the rp process

Mass excesses of short-lived A=2Z-1 nuclei (63)Ge, (65)As, (67)Se, and (71)Kr have been directly measured to be -46,921(37), -46,937(85), -46,580(67), and -46,320(141)  keV, respectively. The deduced proton separation energy of -90(85)  keV for (65)As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of (65)As suggest that the majority of the reaction flow passes through (64)Ge via proton capture, indicating that (64)Ge is not a significant rp-process waiting point.

Isospin diffusion and the nuclear symmetry energy in heavy ion reactions

Using symmetric 112Sn+112Sn, 124Sn+124Sn collisions as references, we probe isospin diffusion in peripheral asymmetric 112Sn+124Sn, 124Sn+112Sn systems at an incident energy of E/A=50 MeV. Isoscaling analyses imply that the quasiprojectile and quasitarget in these collisions do not achieve isospin equilibrium, permitting an assessment of isospin transport rates. We find that comparisons between isospin sensitive experimental and theoretical observables, using suitably chosen scaled ratios, permit investigation of the density dependence of the asymmetry term of the nuclear equation of state.

Isotopic scaling in nuclear reactions

A three parameter scaling relationship between isotopic distributions for elements with Z< or =8 has been observed. This allows a simple description of the dependence of such distributions on the overall isospin of the system. This scaling law (termed isoscaling) applies for a variety of reaction mechanisms that are dominated by phase space, including evaporation, multifragmentation, and deeply inelastic scattering. The origins of this scaling behavior for the various reaction mechanisms are explained. For multifragmentation processes, the systematics is influenced by the density dependence of the asymmetry term of the equation of state.

In situ hybridization detection of calcitonin mRNA in routinely fixed, paraffin-embedded tissue sections: a comparison of different types of probes combined with tyramide signal amplification

In situ hybridization (ISH) is a powerful molecular tool used to visualize nucleic acids in tissues and cells. However, its use is limited by the relative lack of sensitivity in detecting low copy numbers of nucleic acids. Several strategies have been developed to improve the threshold levels of in situ detection of nucleic acid by amplification of either target nucleic acid sequences before ISH (such as in situ polymerase chain reaction) or after the hybridization procedure (such as tyramide signal amplification [TSA]). The authors compared the use of different types of probes to detect calcitonin mRNA in 10 cases of formalin-fixed, paraffin-embedded medullary thyroid carcinoma with and without TSA. In addition, dot blot hybridization was used to compare the signal amplification by TSA with oligonucleotide. cDNA, and cRNA probes. These results show that cRNA probes are the most sensitive types of probes for detecting mRNA molecules in formalin-fixed, paraffin-embedded tissue sections and that tyramide amplification can increase the sensitivity for detection of calcitonin mRNA in formalin-fixed, paraffin-embedded tissue sections at least 2- to 4-fold with cRNA probes.

N-Propionyl-1,2-benzisoselenazol-3(2H)-one

The title compound, C(10)H(9)NO(2)Se, crystallizes as flat molecules linked by selenium-oxygen interactions [Se.O = 3.189 (4) A] into a linear chain along the a axis of the triclinic cell. The bond dimensions that are derived from ab initio geometry optimization calculations are similar to those determined from the diffraction measurements.

Isospin fractionation in nuclear multifragmentation

Isotopic distributions for light particles and intermediate mass fragments have been measured for 112Sn+112Sn, 112Sn+124Sn, 124Sn+112Sn, and 124Sn+124Sn collisions at E/A = 50 MeV. Isotope, isotone, and isobar yield ratios are utilized to estimate the isotopic composition of the gas phase at freeze-out. Analyses within the equilibrium limit imply that the gas phase is enriched in neutrons relative to the liquid phase represented by bound nuclei. These observations suggest that neutron diffusion is commensurate with or more rapid than fragment production.

In situ hybridization detection of low copy nucleic acid sequences using catalyzed reporter deposition and its usefulness in clinical human papillomavirus typing

In situ hybridization (ISH) detection of low copy DNA and RNA sequences using nonisotopic probes has been difficult in the past because of a lack of sensitivity. Several techniques, such as ISH with radioisotopic-labeled probes, in situ polymerase chain reaction, in situ reverse transcription polymerase chain reaction, self-sustained sequence replication, and chemiluminescence, have allowed increased sensitivity but have required specialized and often expensive equipment, lengthy protocols, and in the case of radioactive probes, there has been an associated increased health risk. Catalyzed reporter deposition (CARD) combined with ISH (CARD-ISH) increases the signal-generating potential of labeled hybridized probes and allows the detection of low copy sequences of nucleic acids in formalin-fixed, paraffin-embedded tissue sections. To determine the sensitivity of CARD-ISH to detect nucleic acids in routinely processed specimens, we analyzed the detection of HPV 16 and 18 infection in formalin-fixed, paraffin-embedded sections of cultured cell lines, including CaSki cells with 400-600 copies of HPV 16, HeLa 229 cells with 10-50 copies of HPV 18, and SiHa cells with 1-2 copies of HPV 16 using a conventional ISH method and by CARD-ISH. In addition, 20 cases of clinical specimens previously analyzed for HPV 6, 11, 16, 18, 31, 33, and 51 with the Enzo PathoGene kit (Enzo Diagnostics, Inc., Farmingdale, NY, U.S.A.) were reexamined with the CARD-ISH method. The CARD-ISH system detected one to two copies of HPV 16 in the SiHa cells whereas the conventional ISH method did not. Both methods detected HPV 16 and 18 in CaSki and HeLa 229 cells, respectively. Three clinical cases that were previously negative and two weakly positive cases of HPV infection were all strongly positive with the CARD-ISH system, a 25% increase in the detection of positive cases by CARD-ISH. We also showed for the first time that a cocktail of six biotinylated oligonucleotide probes was capable of detecting one to two copies of HPV 16 in SiHa cells. These results show that the CARD-ISH method increases the sensitivity of nonisotopic ISH to the level of detecting one to two copies of HPV DNA in formalin-fixed, paraffin-embedded tissue sections using biotinylated cDNA or oligonucleotide probes.

Donor lazaroid pretreatment improves viability of livers harvested from non-heart-beating rats

BACKGROUND

Lazaroids are potent inhibitors of lipid peroxidation. Whether the compounds can benefit the liver procured from non-heart-beating donors (NHBDs) is unknown.

METHODS

Donor rats were pretreated with lazaroid U74006F (4.5 mg/kg) 1 hour before cardiac arrest, and transplantation was performed in the rats with donor cardiac arrest from 0 to 60, 100, 120, 140, and 160 minutes as lazaroid pretreated groups. The same number of liver transplantations were done in each paired control group without donor lazaroid pretreatment. Recipient survival rates, bile secretion, serum enzymes, and a lidocaine metabolism test were analyzed.

RESULTS

Donor lazaroid pretreatment significantly increased recipient 3-day survival rates in groups with 60, 100, and 120 minutes of warm ischemia and 7-day survival with 60 minutes of warm ischemia. Also, the pretreatment increased bile secretion and reduced serum aspartate aminotransferase and lactate dehydrogenase levels in the lazaroid-pretreated groups.

CONCLUSIONS

Donor U74006F pretreatment improves viability of livers procured from NHBDs.

Study of rat liver transplantation from non-heartbeating cadaver donors

BACKGROUND

The aim of this study was to determine if livers could tolerate prolonged warm ischemia and to determine optimum timing of intervention in the cadaver donor to preserve liver viability. Livers harvested from non-heartbeating donors (NHBDs) would greatly expand the donor pool for transplantation. However, sensitivity of the donor liver to warm ischemia is a major obstacle for successful use of livers from NHBDs. The limit of non-heartbeating time in the donor remains unknown.

STUDY DESIGN

Hepatic transplantation was performed in ten groups of rats with stepwise increase of cardiac arrest time in the donor from zero to 180 minutes with 20-minute intervals. The cardiac arrest time was counted from ligation of the base of the donor's heart to the beginning of cold flushing of the liver. Bile flow, bile acid outputs, hepatic functions, and rat survival rates in each group were compared.

RESULTS

Survival rates from groups 1 to 10 were 83.3, 100, 83.3, 50, 66.7, 50, 16.7, 16.7, zero, and zero percent, respectively. The stepwise increase of non-heartbeating time significantly reduced recipient survival rates after 100 minutes. In addition, the increase caused a stepwise decrease of bile flow rates and bile salt outputs and an increase of serum aspartate aminotransferase and lactate dehydrogenase activities.

CONCLUSIONS

The liver is less sensitive to warm ischemia than formerly believed. Rat livers can be used for transplantation after cardiac arrest up to 140 minutes with a chance of survival.

In vivo cholesterol kinetics in apolipoprotein E-deficient and control mice

The in vivo total body cholesterol transport of homozygous apoE-deficient (-/-) and control (+/+) mice was evaluated by compartmental analysis of plasma cholesterol decay. Body cholesterol fractional catabolic rates of chow fed mutants were less (-/-, 0.17 +/- 0.02; +/+, 0.51 +/- 0.06 day-1) and body cholesterol contents greater (-/-, 68 +/- 5; +/+, 48 +/- 5 mumol) than controls. The body cholesterol expansion of the chow-fed mutant was extracellular with at least half in plasma. Cholesterol transport, i.e., the mass entering, moving through, and exiting the body each day, was similar (-/-, 6.9 +/- 0.7; +/+, 8.5 +/- 0.9 mumol/day) for homozygotes and controls on chow, and both tripled with cholesterol feeding. Differing from controls, however, mutants had considerable expansions of plasma and body cholesterol (-/-, 166 +/- 21; +/+, 59 +/- 11 mumol) with increments in peripheral tissue cholesterol contents. Cholesterol feeding increased control hepatic cholesterol without a change in plasma, whereas mutants had large increments in plasma cholesterol with no change in liver. Consistent with impaired hepatic uptake of cholesterol, mutants had much slower plasma clearance of lipoprotein cholesterol, as well as slower transfer to catabolic pools than normals. Treatment of homozygotes with lovastatin doubled both plasma cholesterol concentration and body cholesterol transport indicating the importance of apoE-dependent cell cholesterol transfer in synthetic down-regulation with this agent. These data indicate that mice lacking apoE have lower affinity hepatic uptake of plasma remnant cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Conservative management of spontaneous ruptured hepatocellular carcinoma

Because most emergent surgical operations for patients with spontaneous ruptured hepatocellular carcinoma (HCC) achieved hemostasis only, a conservative approach was chosen for management of initial bleeding in our institute. Elective surgery was performed in selected patients to attempt resection of the HCC after stabilization of the hemorrhage. From 1971, 68 of 87 patients with ruptured HCC received the conservative treatment, and 19 were treated by emergent surgery during the same period. Overall, one week and one month mortality rates were 26.5 per cent, 48.5 per cent in the conservative group, and 31.6 per cent, 47.4 per cent in the emergent operative group, respectively. Two patients in the emergent operative group underwent partial hepatectomy for a resectability of 10.5 per cent. Fifteen patients in the conservative group received elective laparotomy 1-3 weeks after control of the initial bleeding. Six underwent partial hepatectomy with a resectability of 40.0 per cent. In conclusion, conservative management is an effective approach for control of intraperitoneal hemorrhage in patients with ruptured HCC. Elective surgery on selected patients after hemostasis will increase the cancer resection rate in patients who undergo laparotomy and will give a better life expectancy than emergent laparotomy in patients with ruptured HCC.

Prostaglandin E1 increases survival with extended anhepatic phase during liver transplantation

OBJECTIVE

The authors investigated the intraoperative treatment effects of Prostaglandin E1 (PGE1) for extension of the anhepatic phase and improvement of survival in a rat liver transplant model.

BACKGROUND

Cross-clamping the inferior vena cava and the portal vein during liver transplantation causes severe pathophysiologic changes during surgery. The time of the anhepatic phase is strictly limited and results in a very tenuous period during the liver transplant operation.

METHODS

Prostaglandin E1 was infused at 0.5 microgram/kg/min into five subgroups of rats with 20, 30, 40, 60, and 80 minutes of anhepatic phase during transplantation. Bile secretion, serum aspartate transaminase (AST), lactic dehydrogenase (LDH), and blood gas analysis were studied in the 30-minute subgroup. The results were compared with the sham-operated and control groups.

RESULTS

Intraoperative treatment with PGE1 extended the maximal anhepatic phase from 30 minutes in the sham-operated group up to 80 minutes, and increased survival. Significant changes in the PGE1 treated rats in the 30-minute subgroup included an increase of bile flow and bile salt output and decrease of AST and LDH activities after surgery. Blood gas analysis showed a decrease in acidosis and hypercarbia at the end of the anhepatic phase.

CONCLUSIONS

The PGE1 treatment increased survival with extended anhepatic phase during rat liver transplantation. The beneficial effects can be attributed to its biologic activities.

Study of donor-recipient liver size match for transplantation

OBJECTIVE

This animal experiment investigated the donor-recipient liver size match for safe liver transplantation.

BACKGROUND

In spite of refinements in surgical techniques in reduced liver transplantation, the liver size disparity remains one of the most common complications in pediatric patients. Optimal size matching remains unknown.

METHODS

The experiment compared eight groups of liver-transplanted rats with designated ratios of donor and recipient liver weights. Donor livers harvested from rats weighing 420-520 g were reduced to the designated size by liver lobectomy and implanted in rats weighing 170-240 g. Bile secretion and serum aspartate aminotransferase (AST) activities in groups 2, 4, and 6 were studied after surgery.

RESULTS

Stepwise increase of the ratio of donor and recipient liver weights from 1.04:1 in group 4 to 1.26:1 in group 3, 1.56:1 in group 2, and 2.04:1 in group 1 caused stepwise decrease of survival rates from 83.3% to 66.7%, 16.7%, and 0%, respectively. Stepwise decrease of the ratio from 1.04:1 in group 4 to 0.79:1 in group 5, 0.53:1 in group 6, 0.35:1 in group 7, and 0.24:1 in group 8 also caused stepwise reduction of survival rates from 83.3% to 66.7%, 50%, 0%, and 0% in each group.

CONCLUSION

The range of ratios of donor and recipient liver weights for successful rat liver transplantation is from 0.53:1 to 1.26:1. Increase and decrease of ratios of donor-recipient liver weights from equal size do not increase the recipient survival rates. Recipients of reduced donor liver weights tend to have a higher survival rate than recipients of increased donor liver weights.

Bile secretion and liver regeneration in partially hepatectomized rats

OBJECTIVE

The purpose of this research was to study the correlation between bile secretion and the liver regeneration in the partially hepatectomized rat.

SUMMARY BACKGROUND DATA

Significant alteration in bile formation and secretion is expected in the liver after hepatectomy. There is scant literature, however, about the effects of liver regeneration in bile secretion.

METHODS

The work was done in rats with 50% hepatectomy, 75% hepatectomy, and sham operation as the control. A chronic common bile duct fistula and a duodenal cannula were established for bile collection and the sample analysis on days 1, 3, 5, 7, and 9.

RESULTS

With size reduced in the liver after 50% and 75% hepatectomy, the total bile volume decreased 45.9% and 51.5%, bile salt independent flow decreased 59.3% and 64.9%, bile salt secretion rate decreased 36.1% and 43.4%, bile salt basal synthesis rate decreased 52.3% and 56.4%, phospholipid secretion rate decreased 52.6% and 68.0%, and cholesterol secretion rate decreased 54.3% and 72.4% from control on day 1, respectively. All changes returned to the control level in 3 to 9 days with accompanying increasing liver size during regeneration.

CONCLUSION

Alterations of total bile flow, bile salt independent flow, bile salt secretion rate, bile salt basal synthesis rate, and biliary lipid secretion after partial hepatectomy correlate with the liver regeneration rate in rats. Partial hepatectomy reduces the bile salt independent fraction calculated as per 100 g body weight rather than the dependent fraction. The study of bile salt and biliary lipid secretion is a useful method for monitoring synthetic function in liver regeneration in vivo.

Physiologic study of bile salt and lipid secretion in rats after liver transplantation

OBJECTIVE

This experiment determined the effects of liver transplantation on bile salt kinetics and biliary lipid secretion.

SUMMARY BACKGROUND DATA

Depression of bile secretion in the three main components and bile cholesterol supersaturation with a high incidence of cholesterol stone formation have been documented in patients with end stage liver diseases after transplantation. However, physiologic changes of bile salt and lipid secretion in recipients remain unclear.

METHODS

The study was done using a rat liver transplant model with 1 and 6 hours of donor liver cold preservation in saline. A chronic common bile duct fistula and a duodenal cannula were established for bile collection and the sample biochemical study for 6 days.

RESULTS

Altered bile salt kinetics in liver grafted rats included depressed bile flow for 1-3 hours after the revascularization, decreased bile salt concentration and outputs, reduced bile salt basal synthesis rate, and reduced bile salt pool size during the early postoperative period. Phospholipid concentration and secretion rate depressed for 1-3 days without altered cholesterol level. The uncoupling change of the cholesterol and the other bile components resulted in an increased lithogenic indices in bile on days 2 and 3.

CONCLUSION

Alterations of bile composition and bile salt kinetics occur in liver transplanted rats. The changes may result from injuries of the liver microcirculation and parenchymal cells caused by cold preservation. The study of bile secretion is helpful for evaluation of the initial graft function. The changed ratio of three bile components may be important for cholesterol stone formation in the liver transplant recipient.

A simple method for bile duct anastomosis and interval bile collection in the liver-transplanted rat

A mini T-tube is introduced for the bile duct anastomosis of rat liver transplantation as well as interval bile collection. The validity of the T-tube was evaluated in 14 liver-transplanted rats and compared to 14 rats using traditional stent for bile duct anastomosis. Changes of biliary tree after the T-tube anastomosis were examined by T-tube cholangiography on sample rats at 4 days and at 4 months after liver grafting. Additionally, bile volumes and rates of bile salt secretion were compared in the continuously flowing cannula and the chronic T-tube fistula in normal rats. The results show that the mini T-tube facilitates bile duct anastomosis and study of bile secretion after liver transplantation in rats without increase in surgical difficulty or interference of biliary enterohepatic circulation.

Improved stabilization of conventional (Brooke) ileostomies with the stapler technique

The rate of functional complications of conventional (Brooke) ileostomy is high and endangers the complete postoperative rehabilitation of the patients. About half of these complications (retraction with/without stenosis, intermittent recession, and prolapse) occur within the classical prominent stoma and are caused by displacement of the serosa surfaces. We have stabilized conventional ileostomies in 39 patients with rows of staples placed paramesenterially and longitudinally. The ileum was everted in the classical way in the primary construction of ileostomies in 19 patients. On the other hand, in 11 patients the prominence of the stoma was established by pulling the ileum out through the previously plane-sutured stoma. In addition, 9 patients with ileostomies which were not primarily stabilized were corrected with the stapler technique to treat complications. With follow-up ranging from 0.2 years to 4.2 years, there have been no complications due to sliding of the nipple in these 39 patients. In contrast, there were complications in 37% of 38 patients with non-stabilized ileostomies with follow-up to the second postoperative year. It was more easily reproducible, more exact, and less traumatic to create the stoma prominence by pulling the intestine out from a primarily plane stoma than with classical eversion. With use of the stapler in repairing complications, local ileostomy constructions were no longer required in every second patient. Consequently, a Brooke ileostomy can be constructed more easily with the stapler technique, ensuring long-term function or restoration of function.

Beneficial effects of prewarming the donor liver for rat liver transplantation

Cold preservation of donor liver can injure the microcirculation enough to impair the function and survival of the transplanted liver. In this study, prewarming the donor liver to 10 degrees C to 12 degrees C after cold storage prior to implantation significantly increased survival rates in rats 1 week after surgery. Following 6, 8, or 9 hours of cold storage in chilled normal saline, prewarming increased survival rates from 40% to 78.6%, from 0% to 35.7%, and from 0% to 14.3%, respectively. The results suggest that pretreatment of the donor liver with warmth following cold storage and before implantation will improve the survival rate of liver transplanted rats.

[Ileostomy--stabilization by stapler technique]

In order to prevent nipple-sliding of the everted small bowel, conventional Brooke ileostomies in 26 patients were stabilized on both sides of the mesentery by longitudinal rows of staples. There were no early complications. With respect to historical controls with unstapled ileostomies, late complications (retraction, prolapse) could be reduced from about 16 to 0% in a median observation time of 2 years. The ileostomies were stable in size and form and therefore appliances were facilitated.

Viable but nonculturable bacteria in drinking water

Klebsiella pneumoniae, Enterobacter aerogenes, Agrobacterium tumefaciens, Streptococcus faecalis, Micrococcus flavus, Bacillus subtilis, and Pseudomonas strains L2 and 719 were tested for the ability to grow and maintain viability in drinking water. Microcosms were employed in the study to monitor growth and survival by plate counts, acridine orange direct counts (AODC), and direct viable counts (DVC). Plate counts dropped below the detection limit within 7 days for all strains except those of Bacillus and Pseudomonas. In all cases, the AODC did not change. The DVC also did not change except that the DVC, on average, were ca. 10-fold lower than the AODC.

Survival and viability of nonculturableEscherichia coli andVibrio cholerae in the estuarine and marine environment

Plating methods for estimating survival of indicator organisms, such asEscherichia coli, and water-borne pathogens includingVibrio cholerae, have severe limitations when used to estimate viable populations of these organisms in the aquatic environment. By combining the methods of immunofluorescent microscopy, acridine orange direct counting, and direct viable counting, with culture methods such as indirect enumeration by most probable number (MPN) estimation and direct plating, it was shown that bothE. coli andV. cholerae undergo a "nonrecoverable" stage of existence, but remain viable. Following 2-week incubations in saltwater (5-25%o NaCl) microcosms, total counts, measured by direct microscopic examination of fluorescent antibody and acridine orange stained cells, remained unchanged, whereas MPN estimates and plate counts exhibited rapid decline. Results of direct viable counting, a procedure permitting estimate of substrate-responsive viable cells by microscopic examination, revealed that a significant proportion of the nonculturable cells were, indeed, viable. Thus, survival of pathogens in the aquatic environment must be re-assessed. The "die-off" or "decay" concept may not be completely valid. Furthermore, the usefulness of the coliform and fecal coliform indices for evaluating water quality for public health purposes may be seriously compromised, in the light of the finding reported here.