[Determination of 14 volatile organic compounds in urine by headspace gas chromatography-mass spectrometry].

Objective: To establish a automatic headspace gas chromatography-mass spectrometry (HS/GC-MS) method for the determination of 14 volatile organic compounds in urine. Methods: In September 2022, 10 ml urine sample was taken into a 20 ml headspace bottle, balanced for 30 min at 65 ℃, and then detected by HS/GC-MS and quantified by external standard method. Results: The 14 volatile organic compounds showed good linearity at 0.2-8.0 µg/L and 0.1-4.0 µg/L, with correlation coefficients ranging from 0.9956-0.9999. The recoveries were 79.8%-113.1% with relative standard deviations 0.05%-0.27% when three different concentration levels were added. Detection limit was 0.03-0.05 µg/L. Conclusion: The method is simple and convenient, and the recovery and precision meet the requirements. It can be used for the determination of common volatile organic compounds in urine.

[Green channel construction mode and development of stroke center in China].

Stroke poses a social and economic burden worldwide.Intravenous thrombolytic therapy and endovascular interventional therapy are recommended as early as possible for patients with acute ischemic stroke in many national and international guidelines, however, their clinical applications are limited due to their strong time dependence.To date, the treatment of acute stroke in China has many problems, such as backward development of hospital treatment process and shortage of stroke professionals.Establishing a complete stroke green channel and maintaining its smooth operation contributes to the most important and effective way to promote thrombolytic therapy, which requires setting a clear target time, appropriately adjusting the hospital layout and hardware and software investment, attaching importance to team building and clear job responsibilities.Moreover, the most important task is to improve the green channel process through replacing the "serial mode" with the "parallel mode", making full use of the first aid map of stroke, bridging the gap between pre-hospital and in-hospital treatment, and popularizing stroke-related knowledge.In recent years, considerable progress has been made in the construction of stroke green channel in China.The implementation of the above-mentioned reform mode may minimize pre-hospital and in-hospital delays, expand the benefit population of stroke and thus improve the early treatment rate of acute ischemic stroke.

[Value of contrast - enhanced ultrasonography and acoustic radiation force impulse elastography in identification of boundary range and viability of hepatic alveolar echinococcosis].

OBJECTIVE: To investigate the biologic viability and boundary range of hepatic alveolar echinococcosis (HAE) by the contrast-enhanced ultrasonography (CEUS) and acoustic radiation force impulse elastography (ARFI). METHODS: Totally 27 HAE patients confirmed by pathology underwent CEUS and ARFI examinations. RESULTS: Gray scale sonography of HAE showed unclear boundary, inhomogeneous, and middle hyperechoic nodules, and the maximum area was (6.08 ± 4.47) cm2 in 27 lesions. CEUS of HAE showed non-enhancement in three phases and black hole sign. Circumferential enhancement on the pe riphery of the lesion was synchronized with the liver parenchyma and showed "fast in and slow out". The maximum area was (8.87 ± 4.83) cm2. The area of ECUS was larger than gray scale sonography in HAE (t = 2.20, P = 0.03). The mean shear wave velocities (SWVs) of the interior, the boundary range, and the surrounding liver tissues of HAE were statistically different by ARFI (F = 84.538, P < 0.001), and the interior had the highest values. CONCLUSIONS: CEUS and ARFI examinations can detect the biologic viability and boundary range of migrating zone around HAE, which is valuable for guiding treatment, judging curative effect, and predicting prognosis.

Isolated cortical vein thrombosis: a widely variable clinicoradiological spectrum.

BACKGROUND/AIMS: The aim of this study is to highlight the variable clincoradiological spectrum of isolated cortical vein thrombosis (ICoVT), which seems to remain a challenge to clinicians. CASES REPORTS: We reported 3 patients with this diagnosis. One presented with only an epileptic seizure, one with worsening headache, seizures, mental disorder, speech disturbance and right-sided weakness, and the other with seizures and fluctuating paralysis in her left-sided limbs. Brain images were manifested with a strand-like abnormal signal, a large hemorrhagic infarction and a continuously enlarged space-occupying massive edema, respectively. CONCLUSIONS: Neurologic features and brain imaging of ICoVT are highly variable, which might be partly responsible for the underestimation of ICoVT. Clinical diagnosis should probably be evoked more often.

Somatostatin receptors SSTR2 and SSTR5 are expressed in the human thoracic duct.

Somatostatin and its analog octreotide have been used successfully to treat postoperative chylothorax, and it has been shown that octreotide binds with high affinity to somatostatin receptor (SSTR) subtypes 2 and 5. Therefore, we investigated expression of SSTR2 and SSTR5 in the human thoracic duct by immunohistochemistry. Normal rat pancreas was used as a positive control for antibodies against SSTR2 and SSTR5, and Factor VIII-related antigen, SMA, actin, elastin, or collagen type II, III, IV or V antibodies were used to identify cell types and structures within the human thoracic duct. The antibodies against SSTR2 and SSTR5 worked well and yielded positive staining in control rat islets. In the human thoracic duct, SSTR2 was present in smooth muscle cells and some scattered structures which were stained by antibodies against Factor VIII-related antigen, SMA, actin, elastin or collagen type II, III, IV or V. SSTR5 was also present in smooth muscle cells. The presence of SSTR2 and SSTR5 in the human thoracic duct sheds light on the mechanism of somatostatin and octreotide use in the successful treatment of chylothorax and offers new molecular pathways to explore for potential future therapies.

NMR studies of the association of cytochrome b5 with cytochrome c.

In an effort to gain greater insight into the molecular mechanism of the electron-transfer reactions of cytochrome b(5), the bovine cytochrome b(5)-horse cytochrome c complex has been investigated by high-resolution multidimensional NMR spectroscopy using (13)C, (15)N-labeled cytochrome b(5) expressed from a synthetic gene. Chemical shifts of the backbone (15)N, (1)H, and (13)C resonances for 81 of the 82 residues of [U-90% (13)C,U-90% (15)N]-ferrous cytochrome b(5) in a 1:1 complex with ferrous cytochrome c were compared with those of ferrous cytochrome b(5) in the absence of cytochrome c. A total of 51% of these residues showed small, but significant, changes in chemical shifts (the largest shifts were 0.1 ppm for the amide (1)H, 1.15 for (13)C(alpha), 1.03 ppm for the amide (15)N, and 0.15 ppm for the (1)H(alpha) resonances). Some of the residues exhibiting chemical shift changes are located in a region that has been implicated as the binding surface to cyt c [Salemme, F. R. (1976) J. Mol. Biol. 10, 563-568]. Surprisingly, many of the residues with changes are not located on this surface. Instead, they are located within and around a cleft observed to form in a molecular dynamics study of cytochrome b(5) [Storch, E. M., and Daggett, V. (1995) Biochemistry 34, 9682-9693](.) The rim of this cleft can readily accommodate cytochrome c. Molecular dynamics simulations of the Salemme and cleft complexes were performed for 2 ns and both complexes were stable.

Surgical treatment of Boerhaave's syndrome: when, how and why?

Ten cases of Boerhaave's syndrome have been treated in this hospital from 1983-1998. Nine patients underwent surgery resulting in complete recovery in seven cases and two postoperative deaths. One was treated with a satisfactory outcome. Vomiting was considered to be the determinative factor for the illness in eight cases. The relationship between the rupture of the esophagus and vomiting and the mechanism of its occurrence based on anatomy and pathophysiology is discussed. It is believed that the most beneficial time to perform surgery is based on the general condition of the patient. The surgical procedure should consist of closure of the lacerated esophagus, a complete clearance of the fibrinous coating on the surface of the pleura, mobilization of a pedicled omentum pad and a gastrostomy. The chest should be entered from the side where the esophagus was lacerated or the X-ray examination showed hydrothorax or hydropneumothorax. The most important factor to guarantee a successful outcome for surgery is a complete clear off of the empyema and early expansion of the lung in addition to effective nutritional support.

Lipids may not be involved in the recognition of apocytochrome C during its transportation.

It was shown that apocytochrome c was less insertion into monolayers from outer mitochondrial membrane lipids than into those from microsomal membrane lipids; the alpha-helix content of apocytochrome c induced by small unilamellar vesicles prepared from outer mitochondrial membrane lipids was less than by those from microsomal membrane lipids; the import efficiency of apocytochrome c into large unilamellar vesicles from outer mitochondrial membrane lipids was also lower than into those from microsome membrane lipids. No specific affinity between apocytochrome c and outer mitochondrial membrane lipids could be found. Import of apocytochrome c across the intact mitochondria, sealed outer mitochondrial membrane and microsome membrane vesicles was compared. Results showed that apocytochrome c was accumulated only in mitochondria, but not the other two kinds of vesicles.

New thymidine triphosphate analogue inhibitors of human immunodeficiency virus-1 reverse transcriptase.

Several novel imidotriphosphate analogues of thymidine have been synthesized and have been shown to be effective inhibitors of human immunodeficiency virus-1 reverse transcriptase (HIV-1 RT). When the alpha,beta-bridging oxygens of thymidine triphosphate (TTP) and 3'-azido-3'-deoxythymidine 5'-triphosphate (AZTTP) were replaced by a nitrogen, the resulting analogues were no longer substrates but instead became competitive inhibitors of HIV-1 RT. The most potent of the alpha,beta-imidotriphosphate derivatives tested was thymidine 5'-[alpha,beta-imido]triphosphate (TMPNPP, 1a). This analogue has a Ki value of 2.4 microM, inhibiting HIV-1 RT 400-fold more potently than it inhibits DNA polymerase I large fragment (Klenow). 3'-Azido-3'-deoxythymidine 5'-[alpha,beta-imido]triphosphate (AZTMPNPP, 1b) gave a Ki value about 10-fold greater than that for TMPNPP, indicating that a 3'-azido substituent decreases the affinity of AZTTP to HIV-1 RT relative to the normal 3'-OH substituent. Dideoxythymidine 5'-[alpha,beta-imido]triphosphate (ddTMPNPP, 1c) was intermediate in potency, giving a Ki value of 15 microM. In contrast, substitution at the beta,gamma-bridging oxygen by nitrogen did not block the enzymatic cleavage of the adjacent alpha,beta-phosphate linkage, and 3'-azidothymidine 5'-[beta,gamma-imido]triphosphate (AZTMPPNP, 1e), the 5'-[beta,gamma-imido]triphosphate analogue of AZTTP, is therefore both a substrate for and a potent inhibitor of HIV-1 RT with an observed Ki value of 87 nM. Further nitrogen substitution of the bridging oxygens in the phosphate chain decreases the inhibitory potency by approximately 10-fold, as in the case of thymidine 5'-[alpha,beta:beta,gamma-diimido]triphosphate (TMPNPNP, 1d).

The observed inhibitory potency of 3'-azido-3'-deoxythymidine 5'-triphosphate for HIV-1 reverse transcriptase depends on the length of the poly(rA) region of the template.

The inhibitory potency of 3'-azido-3'-deoxythymidine 5'-triphosphate (AZTTP) against HIV-1 reverse transcriptase (HIV-1 RT) has been further evaluated. The results indicate that the previously reported low Ki values for AZTTP against HIV-1 RT (2.35 nM) are due neither to the to the direct tight binding of AZTTP to HIV-1 RT nor to the interaction of the enzyme with AZTMP moiety terminated primer-templates, but instead they are an artifact of the use of a homotemplate-primer [poly(rA).oligo(dT)]. With a set of RNAs of defined sequence as templates, we demonstrate that the observed Ki value for AZTTP depends on the length of the poly(rA) region following the primer in the RNA template. The more adenosyl residues in the RNA template that are available for processive incorporation of TMP moieties, the lower is the observed Ki value for AZTTP. Since the potencies of new inhibitors of HIV-1 RT are usually compared with that for AZTTP, these results have important consequences for the process of discovery of new HIV inhibitors that are of potential use in AIDS therapy.

The TIS11 primary response gene is a member of a gene family that encodes proteins with a highly conserved sequence containing an unusual Cys-His repeat.

The TIS11 primary response gene is rapidly and transiently induced by both 12-O-tetradecanoylphorbol-13-acetate and growth factors. The predicted TIS11 protein contains a 6-amino-acid repeat, YKTELC. We cloned two additional cDNAs, TIS11b and TIS11d, that contain the YKTELC sequence. TIS11, TIS11b, and TIS11d proteins share a 67-amino-acid region of sequence similarity that includes the YKTELC repeat and two cysteine-histidine containing repeats. TIS11 gene family members are not coordinately expressed: (i) unlike TIS11, the TIS11b and TIS11d mRNAs are detectable in quiescent Swiss 3T3 cells and are not dramatically induced by 12-O-tetradecanoylphorbol-13-acetate; (ii) cycloheximide superinduction does not occur for TIS11b and TIS11d; and (iii) unlike TIS11, TIS11b expression is extinguished in PC12 pheochromocytoma cells.

Stabilization and activation of recombinant human immunodeficiency virus-1 reverse transcriptase-P66.

Human immunodeficiency virus-1 reverse transcriptase-p66 is surprisingly unstable at 4 degrees C in a typical reverse transcriptase buffer that provides complete stability when enzyme is frozen at -70 degrees C. Incorporation of (rA)n(dT)12-18 template-primer in the buffer vastly improved solution stability of dilute enzyme. Incorporation of 1.0 M ammonium phosphate in the buffer promoted an unexpected and reproducible approximately 260% activation of enzyme. In addition, even enzyme that had been inactivated to 13% of its initial activity could be reactivated to the same approximately 260% higher activity level indicating a reversible interconversion of two forms of the enzyme. The effects of chaotropic and antichaotropic salts coupled with a prior observation of p66 monomer-dimer equilibrium provide suggestive evidence that these two forms of enzyme are monomeric and dimeric p66.

Specificity of S-adenosylmethionine synthetase for ATP analogues mono- and disubstituted in bridging positions of the polyphosphate chain.

The entire family of ATP analogues that are either mono- or disubstituted with imido and methylene bridges in the polyphosphate chain of ATP have been investigated as substrates and inhibitors of S-adenosylmethionine synthetase (ATP:L-methionine S-adenosyltransferase). The disubstituted analogues adenosine 5'-(alpha,beta:beta,gamma-diimidotriphosphate) (AMPNPNP) and adenosine 5'-(alpha,beta:alpha,beta'-diimidotriphosphate) [AMP(NP)2] have been synthesized for the first time, and a new route to adenosine 5'-(alpha,beta:beta,gamma-dimethylenetriphosphate) (AMPCPCP) has been developed. S-Adenosylmethionine synthetase catalyzes a two-step reaction: the intact polyphosphate chain is displaced from ATP, yielding AdoMet and tripolyphosphate, followed normally, but not obligatorily, by the hydrolysis of the tripolyphosphate to pyrophosphate and orthophosphate. Uniformly, the imido mono- or disubstituted derivatives are both better substrates and better inhibitors than their methylene counterparts. AMPNPNP reacts rapidly to give a single equivalent of product per active site, but subsequent turnovers are at least 1000-fold slower, enabling it to be used to quantify enzyme active site concentrations. In contrast, AMPCPCP is not detectably a substrate (less than 10(-5)% of ATP). AMP(NP)2, a branched isomer of linear AMPNPNP, was not a substrate but was a linear competitive inhibitor, greater than 100 fold more potent than ADP, indicating a reasonable degree of bulk tolerance at the alpha-phosphoryl group binding site.(ABSTRACT TRUNCATED AT 250 WORDS)