[Association between mild cognitive impairment and all-cause mortality in elderly population in China: a Meta analysis]

Objective: To quantitatively evaluate the association between mild cognitive impairment and all-cause mortality. Methods: The research papers of the association between cognitive impairment and all-cause mortality in the elderly in the databases of PubMed, EMBASE, Wang Fang data and CNKI published as of August 1, 2021 were comprehensively retrieved. Software R 4.02 was used for Meta-analysis. Results: A total of 9 research papers were included, involving 48 709 patients. The quality of included papers was high. The results of Meta-analysis showed that the association between mild cognitive impairment and the increased risk of all-cause mortality was statistically significant. Compared with the normal cognitive population, the risk of mortality in the elderly with mild cognitive impairment increased by 39% (HR=1.39, 95%CI: 1.18-1.63). Conclusions: The current research evidence showed that mild cognitive impairment assessed by MMSE screening scale can be used as an independent predictor of the increased risk of all-cause mortality in the elderly population in China. However, due to the limitation of the number of included studies and sample size, the conclusions need to be supported by more evidence studies.

Prussian Blue Analogue-derived co/fe bimetallic nanoparticles immobilized on S/N-doped carbon sheet as a magnetic heterogeneous catalyst for activating peroxymonosulfate in water

While Co is the most effective metal for activating PMS, extensive efforts are made to develop Co/Fe species (CF) (e.g., CoFe₂O₄) for imparting magnetic properties and facilitating recovery of catalysts. When carbon substrates are doped with heteroatoms (e.g., S and N) and CF is embedded within the heteroatom-doped carbon matrix, synergies can occur to boost catalytic activities. This study proposes an alternative CF-bearing carbonaceous composite, a cobalt-containing Prussian Blue Analogue (PBA) (Co₃[Fe(CN)₆]₂) is employed as a precursor for preparing CF species embedded in N-doped carbon matrix and immobilized on S/N-co-doped carbon (SNC). Specifically, PBA in-situ grows on SNC by a heat treatment of trithiocyanuric acid to form PBA@SNC, which is then carbonized into CF species@SNC (CF@SNC). By adopting Amaranth degradation as a model reaction, CF@SNC shows a higher catalytic activity (k_app = 0.230 min^-1) than CF (k_app = 0.152 min^-1) and SNC (k_app = 0.016 min^-1) for activating PMS. In comparison with Co₃O₄, CF@SNC exhibits a higher catalytic activity for PMS activation. CF@SNC renders a relatively low E_a value (53 kJ/mol) for Amaranth degradation in comparison to other reported catalysts. These comparisons demonstrate the advantageous features of CF@SNC as a magnetic and efficient catalyst for PMS activation.

Bendable Network Built with Ultralong Silica Nanowires as a Stable Separator for High-Safety and High-Power Lithium-Metal Batteries

Separators are key safety components for electrochemical energy storage systems. However, the intrinsic poor wettability with electrolyte and low thermal stability of commercial polyolefin separators cannot meet the requirements of the ever-expanding market for high-power, high-energy, and high-safety power systems, such as lithium-metal, lithium-sulfur, and lithium-ion batteries. In this study, scalable bendable networks built with ultralong silica nanowires (SNs) are developed as stable separators for both high-safety and high-power lithium-metal batteries. The three-dimensional porous nature (porosity of 73%) and the polar surface of the obtained SNs separators endue a much better electrolyte wettability, larger electrolyte uptake ratio (325%), higher electrolyte retention ratio (63%), and ∼7 times higher ionic conductivity than that of commercial polypropylene (PP) separators. Moreover, the pore-rich structure of the SNs separator can aid in evenly distributing lithium and, in turn, suppress the uncontrollable growth of lithium dendrites to a certain degree. Furthermore, the pure inorganic structure endows the SNs separators with excellent chemical and electrochemical stabilities even at elevated temperatures, as well as excellent thermal stability up to 700 °C. This work underpins the utilization of SNs separators as a rational choice for developing high-performance batteries with a metallic lithium anode.

Cobalt-impregnated biochar produced from CO2-mediated pyrolysis of Co/lignin as an enhanced catalyst for activating peroxymonosulfate to degrade acetaminophen

-While sulfate radical (SO₄^-)-based processes are useful to degrade acetaminophen (ACE), studies of using peroxymonosulfate (PMS) to degrade ACE are quite limited. In addition, although Co is validated as the most effective metal for activating PMS, very few Co catalysts have been developed and investigated for activating PMS to degrade ACE. Since carbon is a promising substrate to support Co nanoparticles (NPs) to form Co/carbon composite catalysts, most existing carbon substrates require delicate fabrications. As biochar is an easy-to-obtain but versatile carbon material, pyrolysis of Co/lignin affords an advantageous Co-impregnated biochar (CoIB) as an attractive catalyst for PMS activation. Specifically, as CO₂ substitutes N₂ as a reaction medium for pyrolysis of Co/lignin, the syngas production from pyrolysis can be substantially improved and a magnetic CoIB is afforded. This CoIB consists of evenly-distributed Co nanoparticles (NPs) impregnated in carbon matrices of biochar, and possesses several superior characteristics, such as high porosity, large surface area and magnetism, enabling CoIB a promising catalyst for activating PMS to degrade ACE. CoIB also shows a much higher catalytic activity of PMS activation than CoIBN₂, and Co₃O₄ for degrading ACE. CoIB is also recyclable for activating PMS to effectively degrade ACE for multiple cycles. The ACE degradation pathway by this CoIB-activated PMS is proposed according to the degradation products. These findings validate that CoIB is assuredly an advantageous heterogeneous catalyst, which can be easily prepared from pyrolysis of Co/lignin in CO₂ with concomitant enhanced syngas production for effectively activating PMS to degrade ACE.

Measurement of the Electron Antineutrino Oscillation with 1958 Days of Operation at Daya Bay

We report a measurement of electron antineutrino oscillation from the Daya Bay Reactor Neutrino Experiment with nearly 4 million reactor ν[over ¯]_{e} inverse β decay candidates observed over 1958 days of data collection. The installation of a flash analog-to-digital converter readout system and a special calibration campaign using different source enclosures reduce uncertainties in the absolute energy calibration to less than 0.5% for visible energies larger than 2 MeV. The uncertainty in the cosmogenic ^{9}Li and ^{8}He background is reduced from 45% to 30% in the near detectors. A detailed investigation of the spent nuclear fuel history improves its uncertainty from 100% to 30%. Analysis of the relative ν[over ¯]_{e} rates and energy spectra among detectors yields sin^{2}2θ_{13}=0.0856±0.0029 and Δm_{32}^{2}=(2.471_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the normal hierarchy, and Δm_{32}^{2}=-(2.575_{-0.070}^{+0.068})×10^{-3}  eV^{2} assuming the inverted hierarchy.

Ferrocene-modified iron-based metal-organic frameworks as an enhanced catalyst for activating oxone to degrade pollutants in water

Ferrocene (Fc) has been regarded as a useful catalyst for activating Oxone to generate sulfate radicals (SR) in degradation of organic pollutants. Nevertheless, direct usage of Fc molecules in aqueous solutions may lead to difficult recovery and aggregation. While a few attempts have immobilized Fc on several substrates, these substrates exhibit very low surface areas/porosities and, especially, do not offer significantly additional contributions to catalytic activities. In this study, a Fe-containing metal organic frameworks (MOFs), MIL-101, is particularly selected for the first time as a support to immobilize Fc chemically. Through the Schiff base reaction, ferrocenecarboxaldehyde can react with amine-functionalized MIL-101 (namely, MIL-101-NH₂) to form Fc-modified MIL-101 (Fc-MIL). As Fc-MIL consists of both Fe from MIL-101 and Fc and also exhibits high surface areas, it appears as a promising catalyst for activating Oxone. Catalytic activities for Oxone activation by Fc-MIL are studied using batch-type experiments of amaranth dye degradation. Fc-MIL shows higher catalytic activities than its precursor MIL-101-NH₂ owing to the modification of Fc, which equips with MIL-101 with more catalytic sites for activating Oxone. Besides, Fc-MIL also outperforms the benchmark catalyst of Oxone activation, Co₃O₄, to degrade amaranth. In comparison to the other reported catalysts, Fc-MIL shows the much smaller activation energy for amaranth degradation, proving its advantage over other catalysts. The synthesis technique proposed here can be also employed to develop other Fc-modified MOFs for other environmental catalysis applications.

Cobalt ferrite nanoparticles supported on electrospun carbon fiber as a magnetic heterogeneous catalyst for activating peroxymonosulfate

Cobalt ferrite (CF) nanoparticle (NP) represents a promising alternative to Co3O4 NP for peroxymonosulfate (PMS) activation in view of its strong magnetism for easy recovery. As CF NPs in water are prone to agglomerate, a few attempts have been made to immobilize CF NPs on substrates. While carbonaceous supports are more favorable owing to their earth abundancy, the study of carbon-supported CF for PMS activation is limited to graphene-based CF, which, however, requires complicated protocols to prepare. As carbon-supported CF, by straightforward preparation, is still greatly desired, this study aims to employ electrospinning techniques for preparing carbon-supported CF by carbonizing an electrospun CF-embedded polyacrylonitrile (PAN) fiber. After carbonization, the CF-PAN fiber is converted into CF-embedded carbon nanofiber (CF@CNF), which contains well distributed CF NPs, high magnetism and stable carbon support, making CF@CNF a highly promising catalyst for activating PMS. As amaranth decolorization is used as a model reaction, CF@CNF is able to activate PMS for generating sulfate radicals and then decolorize amaranth in water. Amaranth decolorization by CF@CNF-PMS is also substantially facilitated at elevated temperature, and enhanced under the weakly acidic condition. CF@CNF also remains effective to activate PMS even in the presence of salts and surfactants, and re-usable over multiple cycles. Compared to other reported catalysts, CF@CNF also exhibited a much lower Ea value (35.8 kJ/mol) for amaranth decolorization. These features validate that CF@CNF is an advantageous and convenient catalyst for activating PMS.

Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW_{th} reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective ^{239}Pu fission fractions F_{239} from 0.25 to 0.35, Daya Bay measures an average IBD yield σ[over ¯]_{f} of (5.90±0.13)×10^{-43}  cm^{2}/fission and a fuel-dependent variation in the IBD yield, dσ_{f}/dF_{239}, of (-1.86±0.18)×10^{-43}  cm^{2}/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the ^{239}Pu fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1σ. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes ^{235}U, ^{239}Pu, ^{238}U, and ^{241}Pu. Based on measured IBD yield variations, yields of (6.17±0.17) and (4.27±0.26)×10^{-43}  cm^{2}/fission have been determined for the two dominant fission parent isotopes ^{235}U and ^{239}Pu. A 7.8% discrepancy between the observed and predicted ^{235}U yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

Limits on Active to Sterile Neutrino Oscillations from Disappearance Searches in the MINOS, Daya Bay, and Bugey-3 Experiments

Searches for a light sterile neutrino have been performed independently by the MINOS and the Daya Bay experiments using the muon (anti)neutrino and electron antineutrino disappearance channels, respectively. In this Letter, results from both experiments are combined with those from the Bugey-3 reactor neutrino experiment to constrain oscillations into light sterile neutrinos. The three experiments are sensitive to complementary regions of parameter space, enabling the combined analysis to probe regions allowed by the Liquid Scintillator Neutrino Detector (LSND) and MiniBooNE experiments in a minimally extended four-neutrino flavor framework. Stringent limits on sin^{2}2θ_{μe} are set over 6 orders of magnitude in the sterile mass-squared splitting Δm_{41}^{2}. The sterile-neutrino mixing phase space allowed by the LSND and MiniBooNE experiments is excluded for Δm_{41}^{2}<0.8  eV^{2} at 95%  CL_{s}.

Improved Search for a Light Sterile Neutrino with the Full Configuration of the Daya Bay Experiment

This Letter reports an improved search for light sterile neutrino mixing in the electron antineutrino disappearance channel with the full configuration of the Daya Bay Reactor Neutrino Experiment. With an additional 404 days of data collected in eight antineutrino detectors, this search benefits from 3.6 times the statistics available to the previous publication, as well as from improvements in energy calibration and background reduction. A relative comparison of the rate and energy spectrum of reactor antineutrinos in the three experimental halls yields no evidence of sterile neutrino mixing in the 2×10^{-4}≲|Δm_{41}^{2}|≲0.3  eV^{2} mass range. The resulting limits on sin^{2}2θ_{14} are improved by approx imately a factor of 2 over previous results and constitute the most stringent constraints to date in the |Δm_{41}^{2}|≲0.2  eV^{2} region.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

This Letter reports a measurement of the flux and energy spectrum of electron antineutrinos from six 2.9 GWth nuclear reactors with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls in the Daya Bay experiment. Using 217 days of data, 296 721 and 41 589 inverse β decay (IBD) candidates were detected in the near and far halls, respectively. The measured IBD yield is (1.55±0.04) ×10(-18)  cm(2) GW(-1) day(-1) or (5.92±0.14) ×10(-43)  cm(2) fission(-1). This flux measurement is consistent with previous short-baseline reactor antineutrino experiments and is 0.946±0.022 (0.991±0.023) relative to the flux predicted with the Huber-Mueller (ILL-Vogel) fissile antineutrino model. The measured IBD positron energy spectrum deviates from both spectral predictions by more than 2σ over the full energy range with a local significance of up to ∼4σ between 4-6 MeV. A reactor antineutrino spectrum of IBD reactions is extracted from the measured positron energy spectrum for model-independent predictions.

New measurement of antineutrino oscillation with the full detector configuration at Daya Bay

We report a new measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9×10^{5} GW_{th}  ton days, a 3.6 times increase over our previous results. Improvements in energy calibration limited variations between detectors to 0.2%. Removal of six ^{241}Am-^{13}C radioactive calibration sources reduced the background by a factor of 2 for the detectors in the experimental hall furthest from the reactors. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. The uncertainties in our estimates of sin^{2}2θ_{13} and |Δm_{ee}^{2}| were halved as a result of these improvements. An analysis of the relative antineutrino rates and energy spectra between detectors gave sin^{2}2θ_{13}=0.084±0.005 and |Δm_{ee}^{2}|=(2.42±0.11)×10^{-3}  eV^{2} in the three-neutrino framework.

Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

Sequence and molecular analysis of the rpoA cluster genes from Xanthomonas campestris pv. campestris

The Xanthomonas campestris rpsM (S13)-rpsK (S11)-rpsD (S4)-rpoA (alpha)-rplQ (L17) cluster, encoding RNA polymerase alpha-subunit and four ribosomal proteins, reside in a 3164-bp DNA region. The N-terminal sequence of the authentic alpha-protein determined chemically matches that predicted from the nucleotide sequence. rplQ is monocistronic, instead of being co-transcribed with the other genes as in Escherichia coli. Antiserum against the His-tagged alpha-protein cross-reacted with the E. coli alpha-protein.

Sequence analysis and expression of the filamentous phage phi Lf gene I encoding a 48-kDa protein associated with host cell membrane

One viral strand of phi Lf, a filamentous phage of Xanthomonas campestris pv.campestris, the open reading frame (ORF440) behind gene VI was identified as gene I. This gene codes for pI protein (440 aa, 48 kDa) which was shown to be membrane-bound in the phi Lf-infected host cell by Western blot analysis using the antibody raised against the protein expressed in Escherichia coli. Its predicted amino acid sequence has a nucleotide-binding motif in the N-terminal 97 aa and a membrane-spanning domain (aa 221 to 236). These structural features are characteristic of pIs of several filamentous phages which are transmembrane proteins required for phage assembly. Thus far, nine phi Lf genes have been identified which are organized in the order GII-gX-gV-gVII-gIX-gVIII-gIII-gVI-gI, similar to the genome organization of E. coli filamentous phages.

Isolation and characterization of the Xanthomonas campestris rpoH gene coding for a 32-kDa heat shock sigma factor

Degenerate oligonucleotide primers corresponding to the conserved regions of bacterial heat shock sigma factor RpoH (sigma 32) were used to amplify a 190-bp fragment by PCR on the X. campestris pv. campestris strain 11 chromosome. Using this fragment as a probe, plasmid pXC57 carrying a 4.7-kb insert was isolated from a genomic library of Xc11. Sequence analysis of a stretch of 2,053 bp from the pXC57 insert revealed an ORF encoding a polypeptide of 291 aa (32,854 dal) which displays 59.6% and 57.3% identity to the rpoH gene products of E. coli and P. aeruginosa, respectively. The Xc11 rpoH gene was able to complement the RpoH deficient E. coli strain A7448. Both amino acid and mRNA sequences deduced from the Xc11 rpoH gene show structural features characteristics of the corresponding sequences from those of the gamma subgroup proteobacteria. The RpoH levels in Xc11 were demonstrated to increase transiently in response to heat shock treatment by immunoblot analysis using the polyclonal antibody raised against the purified Xc11 RpoH.

Purification and expression of the gene III protein from filamentous phage phi Lf

The gene III protein (pIII) from phi Lf, a filamentous phage of Xanthomonas campestris pv.campestris, was purified by gel filtration with FPLC. The gIII coding region was amplified by PCR, which was then cloned into pUC18 and expressed in Escherichia coli. The size of both pIII, purified from phage particle and expressed in E. coli, is similar to the value deduced from the nucleotide sequence as shown by Western blot analysis. This is different from the case in Ff phages (f1, fd, and M13), in which the size of pIII observed in SDS-polyacrylamide gel electrophoresis is substantially larger than the deduced value. Upon infection of X. c. pv. vesicatoria carrying cloned phi Lf gIII with phi Xv, a filamentous phage of pv. vesicatoria, the progeny particles in supernatant were able to infect both pv. campestris carrying cloned phi Lf gIII and pv. vesicatoria, indicating that a mixture of authentic phi Xv and chimeric phage consisting of phi Xv DNA and phi Lf pIII was produced. These results suggest pIII to be the adsorption protein required for host recognition.

Identification of gene VI of filamentous phage phi Lf coding for a 10-kDa minor coat protein

ORF95 in the filamentous phage phi Lf genome, locating behind gIII, was identified to be the gene (gVI) coding for minor coat protein pVI (95 amino acids, 10,245 dal). It was shown to be virion associated by Western blot analysis of chloroform-treated phage particles. Computer analysis predicted two transmembrane regions for this protein. Since no signal peptide was suggested and the size estimated by SDS-polyacrylamide gel electrophoresis matches that deduced from nucleotide sequence, it appears to be incorporated into the phage particle as its primary translational product. After completion of this study, eight genes organizing into an order of gVII-gX-gV-gVII-gIX-gIII-gIII-gVI have been identified for phi Lf.

Central core disease associated with scoliosis: report of one case

A 13 year-old girl with scoliosis and central core disease is reported. She was noted to have mild psychomotor developmental delay since early infancy. Scoliosis with minimal muscle weakness was noted at about five years old. The neurological examination disclosed absent knee jerk. The spine MRI showed no significant finding. The serum CK revealed 518 U/L. The muscle biopsy obtained from the quadriceps femoris muscle showed Type 1 fiber atrophy and predominance, as is commonly seen in congenital myopathies. Under nicotinamide adenine dinucleotide dehydrogenase (NADH) and succinate dehydrogenase (SDH) stains, core structures were identified and the diagnosis of central core disease (CCD) was made. Since kyphoscoliosis usually becomes prominent as muscle weakness progresses to loss of ambulation in other myopathies, the disproportionate spinal involvement in central core disease appears to be a striking feature. We suggest that all patients with idiopathic scoliosis deserve a thorough neurological evaluation if congenital myopathies are suspected. Muscle biopsy should also be recommended for a confirmatory diagnosis even if only minimal muscle weakness present. Besides, early detection of CCD helps us to identify the population who are at a higher risk for malignant hyperthermia.

Clinical analysis of 22 infants with afebrile cluster seizures

The inclusion criteria for afebrile cluster seizures in infancy are defined as follows: (1) frequency of afebrile seizures at least 2 episodes within 72 hours; (2) seizure onset between 2 months and 3 years of age; (3) excluding febrile convulsion, central nervous system infections, status epilepticus, well-known epileptic syndromes in infancy (e.g. early myoclonic encephalopathy, early infantile epileptic encephalopathy, benign myoclonic epilepsy, infantile spasms. Lennox-Gastaut syndrome), electrolyte imbalance, watery diarrhea, head injury and intoxication. From 1986 to 1996, retrospectively and prospectively 22 patients were collected who fulfilled the above criteria. Based on whether or not a strong family history was present and a history of mild diarrhea was associated with seizure onset, they were divided into three groups: Group I, benign infantile familial convulsions (4 patients); Group II, cluster seizures with mild diarrhea in infancy (5 patients); Group III, cluster seizures without diarrhea in infancy (13 patients). Before seizure onset and during follow-up, all of the patients had normal development. The seizure pattern in all was generalized, most tonic type with duration of seizure less than five minutes in the majority. Recurrence rate was 100% in Group I and no recurrence in Group II. In 16 patients who were seizure-free over 12 months, the duration of persistence varied from 1 day to 8 months, and was shortest in Group II (range, 1 to 3 days). It was concluded that the vast majority of afebrile cluster seizures in infancy are benign in nature. Whether anticonvulsant therapy is justified must be individualized.

Cloning, sequencing, and expression of the rpoD gene encoding the primary sigma factor of Xanthomonas campestris

A DNA fragment encoding the primary sigma factor from Xanthomonas campestris pv. campestris was cloned and sequenced. The gene (rpoD) encodes a polypeptide of 622 amino acids with a calculated MW of 70,700. The deduced amino acid sequence exhibits extensive sequence homology to the conserved regions of the primary sigma factors from bacteria. The gene product expressed in Escherichia coli, detected by Western blot analysis, had a MW similar to that estimated for the purified protein in SDS-PAGE. The NH2-terminal amino acid sequence determined chemically matched with that deduced from the nucleotide sequence of the rpoD gene. The calculated pI value (9.31) for the X. campestris primary sigma factor is much higher than the values observed for the analogous proteins from other bacteria.

Clinical experience of esophageal ulcers and esophagitis in AIDS patients

In Taiwan, numbers of patients with the acquired immunodeficiency syndrome (AIDS) have been increasing in recent years. We present esophageal disease of different causes in 5(16%) heterosexual men among 31 AIDS patients over a 5-year period. Major symptoms included mild dysphagia in 4 (80%) patients and odynophagia in 3 (60%) patients. The duration of symptoms varied from 3 days to 6 months. The symptoms occurred before the diagnosis of AIDS in 3 patients. At esophagogastroduodenoscopy (endoscopy), all 5 patients had esophagitis and/or esophageal ulcers proved by histopathologic evaluation. Four had Candida esophagitis, 3 had cytomegalovirus esophagitis/ulcers and 2 had idiopathic esophageal ulcerations (IEU). Three patients had different esophagitis/ulcers at the same time or during follow-up. The median CD4 lymphocyte count at the time of diagnosis of esophageal disease was 12.2 cells/mm3 (range, 3 to 35 cells/mm3). The endoscopic pictures of the different causes of esophagitis/ ulcers lack uniformity in number, size and appearance. These observations make a conclusion that all AIDS patients with an esophageal disease should undergo endoscopy with biopsy to obtain a definitive diagnosis.

Cerebellar dysgenesis in infants and children: an experience of 22 cases

There were a total of 22 cases of cerebellar dysgenesis documented by brain sonogram, and/or brain computer-tomography scan, and/or brain magnetic resonance imaging (MRI) in our department over the past 10 years. There were ten males and twelve females. The mean age at diagnosis was 5.79 months. The follow-up period ranged from 2 days to 132 months. Seven cases were suspected upon prenatal examination. Three cases presented with isolated cerebellar hypoplasia, one with Dandy- Walker malformation and three with Joubert syndrome. Seven cases presented with cerebellar dysgenesis complicated with supratentorial brain dysgenesis. Among them, three had vermis hypoplasia with hypoplasia of the corpus callosum, 1 had vermis hypoplasia with holoprosencephaly, 1 had cerebellar hypoplasia with lissencephaly and hypoplasia of corpus callosum, 1 had vermis hypoplasia, agenesis of the corpus callosum and pachygyria, and 1 had cerebellar hypoplasia, hypoplasia of corpus callosum and midline cystic malformation. They all showed severe psychomotor retardation. Six cases showed chromosome anomalies. The neurological outcome for cases with isolated cerebellar hypoplasia was better than the outcome of the complicated cases. MRI is recommended for patients with microcephaly to check for the possibility of combined supratentorial brain dysgenesis. When performing MRI, a median sagittal view should be included. A classification for clinical approach was presented at the same time. In this retrospective study, this classification seemed to have benefits in prediction of clinical outcomes.

Genetic analysis of the HPRT mutation of Lesch-Nyhan syndrome in a Chinese family

BACKGROUND

The Lesch-Nyhan syndrome is an X-linked recessive inherited disease caused by a complete deficiency of hypoxanthine guanine phosphoribosyl-transferase (HPRT) activity. Many different mutations throughout the HPRT coding region of Lesch-Nyhan patients have been described, including single base substitutions, partial or entire gene deletions, gene insertions or endoduplication of exons. However, study of gene mutation in Chinese patients has rarely been reported in Taiwan.

METHODS

Polymerase chain reaction (PCR) and nucleotide sequence analysis were used to identify the location and the nature of the mutation at the HPRT locus in two brothers affected with Lesch-Nyhan syndrome. The HPRT cDNA, amplified from total RNA of patient's peripheral blood by reverse transcription-polymerase chain reaction, was cloned into a pGEM-3Zf(-) vector and then sequenced. Family study involved initial screening using single-strand conformation polymorphism, and further confirmation by direct sequencing of the exon encompassing the mutation.

RESULTS

The mutation identified in these two affected siblings was a single nucleotide substitution, from cytosine to guanine, in exon 3 of the HPRT coding region. This transversion putatively caused a single amino acid substitution from phenylalanine to leucine at codon 74 in the translated protein. This base change was further confirmed by direct sequencing of both the HPRT cDNA fragment and the exon 3 of HPRT gene amplified from genomic DNA. The family study revealed that the patient's mother was a heterozygous carrier, and the mutation seemed to have occurred de novo in a germinal cell from one of the maternal grandparents.

CONCLUSIONS

This is the first family study on Chinese patients with Lesch-Nyhan syndrome identified by molecular analysis in Taiwan. The mutation described herein is a novel substitution which occurs in a suggested "hotspot" of mutation (exon 3) of the HPRT gene. The application of molecular analysis of HPRT-gene allows not only DNA diagnosis by directly detecting the mutant alleles, but also prenatal diagnosis and carrier identification within individual families affected by Lesch-Nyhan syndrome.

Transcription termination at the Escherichia coli thra terminator by spinach chloroplast RNA polymerase in vitro is influenced by downstream DNA sequences

We have investigated the mechanism of transcription termination in vitro by spinach chloroplast RNA polymerase using templates encoding variants of the transcription-termination structure (attenuator) of the regulatory region of the threonine (thr) operon of Escherichia coli. Fourteen sequence variants located within its d(G+C) stem-loop and d(A+T)-rich regions were studied. We found that the helix integrity in the stem-loop structure is necessary for termination but that its stability is not directly correlated with termination efficiency. The sequence of the G+C stem-loop itself also influences termination. Moreover, the dA template stretch at the 3' end of the terminator plays a major role in termination efficiency, but base pairing between the A and U tract of the transcript does not. From the studies using deletion variants and a series of mutants that alter the sequences immediately downstream from the transcription termination site, we found that termination of transcription by spinach chloroplast RNA polymerase was also modulated by downstream DNA sequences in a sequence-specific manner. The second base immediately following the poly(T) tract is crucial for determining the termination efficiency by chloroplast RNA polymerase, but not of the T7 or E.coli enzymes.

Transcription termination at the thr attenuator. Evidence that the adenine residues upstream of the stem and loop structure are not required for termination

The Escherichia coli thr operon attenuator has a structure similar to other Rho-independent terminators. The DNA sequence immediately 5' to the termination site is dG+dC-rich and contains a region of dyad symmetry that, when transcribed into RNA, encodes a hairpin structure in the transcript. It also contains a stretch of 9 consecutive dA-dT residues immediately distal to the region of dyad symmetry which encode uridine residues at the 3' end of the terminated transcript. In addition, the thr attenuator has a stretch of 6 dA-dT residues immediately upstream of the region of dyad symmetry which encode 6 adenines. These adenines could potentially pair with the distal uridines to form a hairpin structure extended by as much as 6 A-U base pairs. In this report we have examined the role of the upstream adenines in transcription termination. We used templates that specify mismatches or create new base pairs in the potential A-U secondary structure of the transcript as well as templates that delete segments of the A residues upstream of the hairpin. We conclude that A-U pairing is not required for efficient transcription termination at the thr attenuator. This conclusion is likely to apply to other Rho-independent terminators that contain hairpin-proximal dA-dT residues.

Leigh syndrome presenting with dystonia: report of one case

A 22-month-old female presented with developmental delay and dystonia. The T2 weighted image of the brain MRI showed bilateral symmetrical high signal lesions over the putamen. An increased serum lactate pyruvate ratio (29.25) and a positive oral glucose lactate stimulation test were noted. Electron microscopic examination showed abnormal mitochondrial aggregation with band cristae in the subsarcolemmal area. These findings were indicative of clinical Leigh's syndrome. However, unusually the mt DNA analysis showed a point mutation at the nucleotide position 8344.

Selection of mutations altering specificity in restriction-modification enzymes using the bacteriophage P22 challenge-phage system

A method for selecting mutants of site-specific DNA-binding proteins has been applied to the study of the EcoRI and RsrI restriction-modification enzymes. Catalytically inactive variants of both endonucleases are shown to function as pseudo-repressors in the bacteriophage P22 challenge-phage assay, and, upon further mutagenesis of the gene encoding R.EcoRI, a variant of that enzyme has been selected which appears to bind EcoRI-methylated GAATTC sequences to the exclusion of unmethylated sites: this specificity is the opposite of that belonging to the native enzyme. Variants of the EcoRI methylase have also been found that lack either catalytic activity or both binding and catalytic activities.

Congestive gastropathy in cirrhotic patients: correlation between endoscopic and histological findings

Congestive gastropathy is a common cause of gastrointestinal bleeding in cirrhotic patients. Forty-six patients with cirrhosis of the liver and 225 control subjects matched in age and sex without cirrhosis of the liver entered the study. We studied the prevalence of congestive gastropathy in cirrhotic patients, and the relationship between endoscopic and histological findings. Congestive gastropathy seen endoscopically was found to be more common in the cirrhotic group than in the control (85% vs. 5%, P < 0.05). The sensitivity, specificity and positive predictive value were 85%, 95% and 76%, respectively. The presence of endoscopic congestive gastropathy was correlated with the severity of liver disease (P < 0.05), but not to the etiology of cirrhosis and the size of esophageal varices with or without red color sign. Endoscopic congestive gastropathy showed no correlation with the histological features including gastritis, interstitial edema, vessel ectasia/congestion and hemosiderin in endoscopic biopsy specimens. In conclusion, congestive gastropathy is a common finding in cirrhotic patients. Its appearance is closely correlated with the severity of liver disease. There is no good correlation between endoscopic congestive gastropathy and mucosal histology.

Lesch-Nyhan Syndrome: report on two brothers

Lesch-Nyhan syndrome is a rare X-linked disease characterized by over-production of uric acid and a central nervous system (CNS) disorder consisting of mental retardation, spasticity, choreoathetosis, and a compulsive form of self-mutilation. A deficiency in hypoxanthine-guanine phosphoribosyl transferase (HPRT) provides the underlying metabolic basis for this disease. A 12 month-old male baby who had orange crystals over the diapers since he was 3 months old was brought to our hospital due to developmental delay. Mental retardation and athetosis were also noted. Chemical analysis revealed hyperuricemia (uric acid 8.6 mg/dl). Urine routine showed microscopic hematuria and uric acid crystals. The activity of HPRT in erythrocyte lysates of parents were both within normal limits, but that of the patient was very low (0.0547 nm/min/mg protein, < 0.05% of control). His younger brother was born 2 months after this disorder diagnosed in this patient. The younger brother was noted to have uric acid crystals over the diapers when he was 40 days old and hyperuricemia (10.6 mg/dl) showed up later. He was also a case of Lesch-Nyhan syndrome since the activity of HPRT in erythrocyte lysates was also low (0.0327 nmol/min/mg protein, < 0.05% of control). Further studies, including carrier detection and deoxyribonucleic acid (DNA) analysis, could be helpful for genetic counseling. This syndrome is rare among Chinese, and this may be due to underdiagnosis.

Salmonella infections in infants and children

BACKGROUND

Salmonella is an important pathogen for infants and children of which multiply resistant strains were recently reported. Our interest was the annual variation of clinical manifestations, serotype and the sensitivity rate for antibiotics during the past decade. Increased incidence of bacteremia in infants is reported. In order to find the predisposing factors of patients with acute gastroenteritis complicated with bacteremia, we conducted a retrospective analysis.

METHODS

We reviewed the records of documented patients who had positive culture for Salmonella in our Pediatric Department from September 1982 to September 1992. Those patients with acute gastroenteritis were divided into two groups: I, those complicated with bacteremia and II, non-bacteremic cases. Then we compared the age, body temperature, severity of clinical symptoms, white blood cell count and Salmonella serotype of these two groups.

RESULTS

There were 180 cases of Salmonella infection in our Pediatric Department during the past decade. The mean age was 14.80 months. Most (88.9%) patients were under two years old and 146 subjects were victims of acute gastroenteritis. Six cases had infection of the central nervous system (CNS). Five cases presented typhoid fever. Of three mortal cases, two died from meningitis with sepsis and one was a victim of malignant lymphoma and septic arthritis complicated with sepsis. Salmonella group B was the most common pathogen. There were no cases of typhoid fever after 1989. The sensitivity to ampicillin, chloramphenicol, and ceftriaxone for group B were 25.7%, 26.1% and 100% respectively. Multiply resistant Salmonella species were not present in our cases. The severity of clinical symptoms varied in significantly between those who had acute gastroenteritis with bacteremia (Group I) and those who had acute gastroenteritis without bacteremia (Group II). However, there was a significant distinction in the average age of the two groups (P = 0.005).

CONCLUSIONS

Although the annual number of cases did not decrease in recent years, the number of cases of typhoid fever did decrease. Most patients were infants and acute gastroenteritis was most common. In our series, the relative sensitivity for ampicillin, chloramphenicol was small over the past decade. Multiply resistant Salmonella species were not found, which may be due to the small sample size.

Congenital tracheal stenosis: a report of two cases

Congenital tracheal stenosis (CTS) is a rare, potentially lethal condition. Two cases were diagnosed in this hospital between 1986 and 1992. Diagnosis was confirmed by endoscopy and radiography. These two cases were noted to have symptoms of airway obstruction after an infectious process. Their outcomes were quite different. The first patient, a victim of CTS diagnosed at two years old, still lives well and has been asymptomatic for subsequent six years, though he has received no surgical intervention. The second patient, a three-month-old female, exhibited an exacerbation after bronchoscopy and died in spite of intensive care. Prompt recognition of symptoms and a thorough evaluation of airway, as well as other anomalies, is essential for proper management of children with CTS. The diagnostic modalities, management and risk factors are discussed.

[Treatment of male breast cancer: an analysis of 41 cases]

41 male patients with breast cancer confirmed pathologically were treated. Of these, 35 were treated by radical mastectomy and 6 by modified radical mastectomy. The patients with axillary lymphatic metastasis were treated by postoperative radiotherapy, chemotherapy. The overall 5-, 10- and 15-year survival rates were 67.6%, 53.3% and 55.0%, respectively. The 15 year survival rates of TNM stage I-II and III patients were 55% and 50% respectively. We conclude that radical or modified radical mastectomy is the rational therapy for male breast cancer. The patients in stage III will benefit from postoperative adjuvant therapy in terms of improving prognosis.

Arthrogryposis multiplex congenita: report of a case of amyoplasia

Arthrogryposis multiplex congenita is a congenital syndrome characterized by multiple congenital joint contractures; and refers to a large heterogeneous group of disorders. We present a 40 days old male baby who has had multiple fixed contractures of joints since birth. Midline capillary hemangioma, internal rotation of bilateral shoulders, extension contracture of elbows, flexed wrists with pronation deformity, flexion and internal rotation of hips, equinovarus of feet were noted. A series of examinations for differential diagnosis including brain sonogram, echocardiogram, muscle echogram, muscle biopsy, chromosome study were performed and all showed normal findings. Amyoplasia was impressed. Early rehabilitation was arranged. Normal intelligence and a normal life span are expected.

Molybdenum requirement of female rats

Sixty 3-wk-old female Sprague-Dawley rats were randomly divided into six groups of 10 animals each. Group 1 was fed for 8 wk purified AIN-76A diet (basal diet) containing 0.025 mg molybdenum/kg diet. Groups 2-6 were fed the same basal diet supplemented with sodium molybdate to provide total dietary Mo of 0.050, 0.100, 0.200, 0.400 and 0.800 mg/kg diet, respectively. Molybdenum concentration in liver and brain increased linearly up to the 0.200 mg Mo/kg diet level. Beyond this level, no further significant increase occurred. Dietary Mo of 0.100 mg/kg elevated the Mo concentration in heart to its maximal level. Supplementation with 0.025 mg Mo/kg to a total of 0.05 mg Mo/kg diet significantly increased Mo concentration in spleen and kidney; higher levels of dietary Mo did not result in further significant responses. Molybdenum supplementation significantly increased the activities of xanthine dehydrogenase/oxidase (XDH), sulfite oxidase and superoxide dismutase in the liver, and of XDH in small intestinal mucosa. Maximal activities were attained at 0.050, 0.050, 0.200 and 0.100 mg Mo/kg diet, respectively. Dietary Mo of 0.200 mg/kg diet was estimated as the Mo requirement of rats fed the AIN-76A diet.

Isolation and footprint analysis of the Escherichia coli thr leader paused transcription complex

The E. coli thr operon leader region contains a cluster of transcription pause sites upstream of the attenuator. In this report, we determine the exact sites of pausing and analyze the structure of the ternary complex by footprint techniques. Under synchronized transcription initiation conditions in vitro, three closely-spaced transcription pause sites were identified. These pause sites appeared downstream of the first region of dyad symmetry, which encodes an RNA hairpin in the transcript, and occurred at positions G112, G114 and A116 of the thr leader RNA. The results showed that the half-life of the thr paused complexes at G112 and G114 could be enhanced by limiting the concentration of the nucleoside triphosphate GTP in the transcription reactions. In addition, the half-life of the paused complexes was shown to increase in the presence of NusA protein. The thr leader complex that paused immediately before residues G112 and G114 of the nascent transcript was isolated and its structure was analyzed with enzymatic and chemical cleavage reagents. The footprinting studies using DNase I showed that there were approximately 35 nucleotides on both strands of the DNA that were protected by RNA polymerase from DNase I cleavage. The DNA segment protected by RNA polymerase is approximately 19 nucleotides upstream and 14 nucleotides downstream of the pause sites. The results from hydroxyl radical footprints also showed a similar pattern of protection at the transcription pause sites. However, no significant differences in the footprinting patterns were observed in the presence or absence of NusA protein.

Hepatic, placental, and fetal trace elements following molybdenum supplementation during gestation

The effect of dietary Mo (Na2Mo(4)2H2O) added to drinking water at levels of 0, 5, 10, 50, or 100 mg on hepatic (gestating dams), placental, and fetal Mo, Cu, Zn, and Fe contents of Sprague-Dawley rats was studied. These elements were determined by a polarographic catalytic procedure for Mo and by atomic absorption spectrophotometry for Cu, Fe, and Zn. Hepatic Mo increased two to sixfold (5-100 mg Mo). There was a 1.5-fold increase in hepatic Cu, significant only at the 50 to 100 mg Mo/L treatment levels. Although the hepatic Fe content of the gestating rats significantly increased with Mo supplementation, the extent of the increase appeared to be influenced by the litter size, fetal weights, and the degree of fetal resorption. Zinc values did not differ at any of the treatment levels. Placental Mo increased 3-76-fold, Cu one to threefold. No differences were observed in placenta Fe or Zn. Fetal Mo increased two to six-fold (10-100 mg/L) and Cu increased one to fivefold. There were no differences in the Fe and Zn content although both of these elements appeared to decline as the level of supplemental Mo increased. Significant correlations were also observed between hepatic, placental, and fetal Mo, Cu, Fe, and Zn. These results suggest that changes in trace mineral status in gestation, owing to high Mo intake, do occur and such occurrences are also reflected in the fetus.

Transcription termination directed by heteroduplex thr attenuator templates. Evidence that the transcript stem and loop structure is the termination signal

We have constructed both homoduplex and heteroduplex restriction fragment templates that contained mutations in the G + C-rich region of dyad symmetry in the Escherichia coli thr operon attenuator and have studied their termination properties in an in vitro transcription system. We found that the DNA sequence of the template strand determines the transcription termination efficiency. We also constructed two double mutant heteroduplex templates to examine the role of possible complementary base pairs between the nontranscribed DNA strand and the nascent RNA in the transcription bubble. There was no indication that the potential DNA-RNA interactions in the G + C-rich region are involved in transcription termination. Taken together, our results are consistent with and extend those obtained by Ryan and Chamberlin (Ryan, T., and Chamberlin, J. (1983) J. Biol. Chem. 258, 4690-4693) for the trp operon attenuator and argue strongly against models that propose that DNA hairpin formation in the nontranscribed DNA strand or pairing of the nascent RNA with the nontranscribed DNA strand are important for transcription termination.

Effect of molybdenum supplementation on hepatic trace elements and enzymes of female rats

The effects of molybdenum (Mo) supplementation in the drinking water at the levels of 0.1, 0.5, 1.0, 2.0, 5.0 and 10.0 mg/l on the hepatic trace element concentrations and enzyme activities of female Sprague-Dawley rats were studied. The mean hepatic Mo concentration increased significantly in the rats supplemented with 0.1 mg Mo/l as compared to the nonsupplemented rats, but a further significant increase did not occur until the supplementation level reached 5-10 mg Mo/l drinking water. Hepatic copper concentration of the group given 0.1 mg Mo/l and hepatic iron content of the groups given 0.1 or 0.5 mg Mo/l were significantly higher than those of the other groups. The hepatic xanthine dehydrogenase/oxidase activity was not significantly affected by Mo supplementation. The hepatic sulfite oxidase (SOX) activity of the group given 0.1 mg Mo/l was significantly higher than that of the nonsupplemented group. The SOX activities of all the other supplemented groups were at a significantly different level intermediate between the first two. The hepatic superoxide dismutase (SOD) activity was significantly higher in the group given 0.1 mg/l than in the other groups. These results indicated that molybdenum enzymes and SOD might not be participants in previously reported anticarcinogenic activity of Mo, as supplementation at the level of 0.1 mg/l had been observed to be inefficacious in inhibiting N-nitrosomethylurea-induced mammary tumor incidence.

Percutaneous superfine-needle aspiration biopsy of intrathoracic lesions guided by simulator

The result of percutaneous superfine-needle aspiration biopsy in 100 patients with intrathoracic lesions guided by simulator is reported. The success rate of aspiration biopsy was 94%, and no major complication was observed. The method of localization by simulator had advantages such as accuracy in localization, no limitation of mass size and site, and a high rate of puncture success. Cell smears obtained by superfine needle were similar to those obtained by fine- or large-bore needles, but fewer complications were encountered. This is a useful technique that can provide early cytological diagnosis, especially for the peripheral type of pulmonary mass.

Comparative study of long-term effects of surgical excision and excision combined with radiotherapy or chemotherapy in breast cancer: an analysis of 192 cases

Clinical data of 192 patients with breast cancer with a primary lesion of 2-5 cm (stage II according to the criteria recommended by the UICC) and with histopathologically confirmed positive axillary lymph nodes were analyzed. The patients were divided into three groups: 1) surgical excision alone; 2) surgery plus irradiation; and 3) surgery plus chemotherapy. It was shown that the 5-year survival rates for these groups were 40.5%, 61.0%, and 62.0%, respectively (P less than .05).

Measures for improving therapeutic results of esophageal carcinoma in stage III: preoperative radiotherapy

Surgical therapeutic results of esophageal carcinoma stage III in 245 cases admitted to our hospital from 1966 to 1982 are reported in this paper. In this series, 171 cases were treated by surgery alone and 74 cases treated with a combination of preoperative radiotherapy and surgery. Of the entire group, 184 cases underwent gastroesophagostomy or colon interposition for esophageal reconstruction preceded by resection of the cancerous esophageal segment. The resectability rate was 75.1%, and the resection operative mortality rate was 7.1%. The 5- and 10-year survival rates were 30.0 and 25.8%, respectively. In the group of 171 cases treated by surgery alone, the resectability rate was 73.1% (125/171), and the resectability in the middle third esophageal carcinoma was only 64.7% (44/68), while in the group of 74 cases treated by combination treatment, the resectability increased to 79.7% (59/74) and the resectability in the middle third esophageal carcinoma increased to 79.3% (46/58). The 5-year survival rate in the combination-therapy group (60.1%) was 42.9% higher than that of the group treated by surgery alone (17.2%) (p less than 0.01). However, the differences in the rates of resection operative mortality and operative complications between these two groups were not significant. Therefore, we think that preoperative radiotherapy for esophageal carcinoma in stage III is an effective measure for improving resectability and survival rate.

Proton magnetic resonance spectroscopy of Klebsiella capsular polysaccharides

The presence of acetate and pyruvate groups in Klebsiella capsular polysaccharides may be demonstrated and estimated quantitatively by running the proton magnetic resonance spectrum of the polysaccharide (as sodium salt) in deuterium oxide at 95 C. Such spectra also permit an assessment to be made of the number of alpha- and beta-linkages in the repeat unit of the polysaccharide structure.