Formation of difluorothionoacetyl-protein adducts by S-(1,1,2,2-tetrafluoroethyl)-L-cysteine metabolites: nucleophilic catalysis of stable lysyl adduct formation by histidine and tyrosine

19F NMR spectroscopy was used in conjunction with isotopic labeling to demonstrate that difluorothionoacetyl-protein adducts are formed by metabolites of the nephrotoxic cysteine conjugate S-(1,1,2,2-tetrafluoroethyl)-L-cysteine (TFEC). To determine which amino acid residues can be involved in adduct formation, the reactivity of TFEC metabolites with a variety of N-acetyl amino acids was also investigated. An N alpha-acetyl-N epsilon-(difluorothionoacetyl)lysine (DFTAL) adduct was isolated and characterized by 19F and 13C NMR spectroscopy and mass spectrometry. N alpha-Acetylhistidine and N-acetyltyrosine were found to act as nucleophilic catalysts to facilitate the formation of both the protein and DFTAL adducts. Adduct formation was greatly reduced when lysyl-modified protein was used as the substrate, indicating that lysyl residues are primary sites of adduct formation. However N alpha-acetyllysine, at concentrations of greater than 100-fold in excess compared to protein lysyl residues, was not effective in preventing binding of metabolites to protein. Therefore, nucleophilic catalysis at the surface of the protein may be an important mechanism for the binding of TFEC metabolites to specific lysyl residues in protein. TFEC metabolites were very reactive with the thiol nucleophiles glutathione and N-acetylcysteine. However, the predicted difluorodithioesters could not be isolated. Both stable difluorothioacetamide and less stable difluorodithioester protein adducts may play a role in TFEC-mediated nephrotoxicity.

[Expression, amplification and rearrangement of c-myc gene in human thyroid carcinoma]

The structure and expression of c-myc oncogene was analyzed by molecular hybridization in tumor tissues from 15 patients with primary thyroid carcinoma, 3 patients with thyroid adenoma and in tissues from 5 normal and 1 adjacent non-neoplastic thyroid. We found that in 9 of the 15 cancer patients, c-myc oncogene was overexpressed (ie, at levels 3-11 times higher than in normal thyroid tissues). Rearrangement of c-myc gene was observed in 4 cancer samples, of which one showed a 150-fold amplification of c-myc gene. Overexpression, amplification of c-myc gene were frequently detected in thyroid cancer patients with more malignant and unfavourable prognosis, which suggested that overexpression, amplification and rearrangement of c-myc oncogene may be associated with unfavourable prognosis of thyroid carcinoma. It has been shown that the activated c-myc oncogene may play an important role in the initiation and progress of thyroid carcinoma.

Biplane transesophageal echocardiography: imaging sections and anatomic segments

In order to recognize correctly the images of transesophageal echocardiography (TEE), in 410 subjects TEE was performed with uniplane or biplane transducer, and in 7 corpses the cardiac anatomic segments were observed, at various levels and in different directions, 9 transverse and 6 longitudinal views were compared with the corresponding cardiac anatomic segments. Based on this study, the authors reported the levels of segments, insertion depth, anatomic structure identification, image characteristics and clinical application of TEE, and the advantages of biplane TEE are discussed.

Structure-activity relationship of miltirone, an active central benzodiazepine receptor ligand isolated from Salvia miltiorrhiza Bunge (Danshen)

Twenty one o-quinonoid-type compounds and one coumarin-type compound related to miltirone (1) have been synthesized with the aim to identify the key structural elements involved in miltirone's interaction with the central benzodiazepine receptor. On the basis of their inhibition of [3H]flunitrazepam binding to bovine cerebral cortex membranes, it is apparent that ring A of miltirone is essential for affinity. Although increasing the size of ring A from six-membered to seven- and eight-membered is well-tolerated, the introduction of polar hydroxyl groups greatly reduces binding affinity. The presence of 1,1-dimethyl groups on ring A is, however, not essential. On the other hand, the isopropyl group on ring C appears to be critical for binding as its removal decreases affinity by more than 30-fold. It can, however, be replaced with a methyl group with minimal reduction in affinity. Finally, linking ring A and B with a -CH2CH2- bridge results in analogue 89, which is 6 times more potent than miltirone at the central benzodiazepine receptor (IC50 = 0.05 microM).

[Renal function of cations excretion in children predisposed to essential hypertension]

We studied the renal function of cations excretion in 86 normal children, aged 4-6 years old. 24-hour urinary excretion of sodium, potassium, calcium, magnesium, copper and zinc were measured before and after acute oral salt loading. The result showed that urinary sodium levels were significantly lower (101.88 mmol/24 h, 126.58 mmol/24 h, respectively, P less than 0.01) in children with family history of essential hypertension than in those without family history after salt loading. This suggests that the children with family history may have hereditary functional defect in the excretion of sodium before developing hypertension. We also found the renal excretions of potassium, calcium and zinc showed difference between children with and without family history of essential hypertension.

Immunological studies of osteoarthritis in bipedal rats

Osteoarthritis (OA) models in bipedal rats were used to study the immune response, including the changes of IgG, antibody dependent cytotoxicity tests toward articular chondrocytes and the matrix. The results revealed significant difference between the bipedal and the quadruped rats. Immunological studies have proved that the OA model of bipedal rats is appropriate for the study of OA.

Rate process parameters of albumen

Both egg white and egg yolk are excellent media for studying photocoagulation due to thermal response of tissue to laser light. They are readily available, consistently the same, and provide a standard biological medium for different labs to compare results. The irradiation parameters for laser coagulation of these media depend upon their optical properties and their temperature-dependent rate reactions. Estimates of the rate process damage coefficients were obtained from constant-temperature water bath experiments. The activation energy E for egg white was estimated to be 92,000 (cal/M*K] and the integration constant A was found to be 3.8 x 10(57) (second-1).

Spatial frequency tuning of human stereopsis

A masking paradigm was employed to measure the spatial frequency selectivity of channels underlying human stereopsis. Observers viewed spatially filtered (0.4 octave bandwidth) random-dot stereograms in which a disparate bar appeared in either the top or bottom half of the display; superimposed on one RDS half-image was a noise target whose spatial frequency content was varied relative to that of the RDS. A staircase procedure was used to measure the monocular noise energy (and hence the signal-to-noise ratio) at which observers could judge the location of the disparate bar on 71% of trials. Statistical analyses showed that the resulting stereoscopic masking functions could be grouped into two sets, one with peak sensitivity at 3 c/deg and the other with peak sensitivity at 5 c/deg. These two channels were observed for both crossed and uncrossed disparities ranging from coarse to fine. Essentially the same results were obtained with binocular noise and with stereo displays flashed too briefly to be affected by eye movements. Our results are inconsistent with models of stereopsis in which the disparity range to which a channel is sensitive varies with that channel's peak spatial frequency. These data imply that the spatial frequency selectivity of stereopsis differs from the tuning of spatial channels underlying the detection and discrimination of form.

A schematic analysis of the Unified Medical Language System

The UMLS is a complex collection of medical terms and relationships derived from standard classifications. Appreciating the scope and layout of these relations from text descriptions of relational schema is difficult. The graphical technique of Logical Data Structure (LDS) representation was employed to illustrate the UMLS schema as a data abstraction, affording additional insights that might otherwise escape notice. An LDS representation of the Metathesaurus offers the following advantages: 1) the separation of a viewpoint from physical data structures enables a global outline of the contents; 2) the graphical map makes the interrelation of data visible; and 3) the logical entities explicitly reflect the decision-making which was implicit or ambiguous in the relational scheme.

Latent Semantic Indexing of medical diagnoses using UMLS semantic structures

The relational files within the UMLS Metathesaurus contain rich semantic associations to main concepts. We invoked the technique of Latent Semantic Indexing to generate information matrices based on these relationships and created "semantic vectors" using singular value decomposition. Evaluations were made on the complete set and subsets of Metathesaurus main concepts with the semantic type "Disease or Syndrome." Real number matrices were created with main concepts, lexical variants, synonyms, and associated expressions. Ancestors, children, siblings, and related terms were added to alternative matrices, preserving the hierarchical direction of the relation as the imaginary component of a complex number. Preliminary evaluation suggests that this technique is robust. A major advantage is the exploitation of semantic features which derive from a statistical decomposition of UMLS structures, possibly reducing dependence on the tedious construction of semantic frames by humans.

Polysaccharide Fraction from Higher Plants which Strongly Interacts with the Cytosolic Phosphorylase Isozyme : I. Isolation and Characterization

From leaves of Spinacia oleracea L. or from Pisum sativum L. and from cotyledons of germinating pea seeds a high molecular weight polysaccharide fraction was isolated. The apparent size of the fraction, as determined by gel filtration, was similar to that of dextran blue. Following acid hydrolysis the monomer content of the polysaccharide preparation was studied using high pressure liquid and thin layer chromatography. Glucose, galactose, arabinose, and ribose were the main monosaccharide compounds. The native polysaccharide preparation interacted strongly with the cytosolic isozyme of phosphorylase (EC 2.4.1.1). Interaction with the plastidic phosphorylase isozyme(s) was by far weaker. Interaction with the cytosolic isozyme was demonstrated by affinity electrophoresis, kinetic measurements, and by (14)C-labeling experiments in which the glucosyl transfer from [(14)C]glucose 1-phosphate to the polysaccharide preparation was monitored.

[Plasma calcitonin gene-related peptide (CGRP) level in patients with essential hypertension]

Calcitonin gene-related peptide (CGRP) is a 37-amine acid bioactive polypeptide and known to be a powerful vascular relaxant. CGRP was measured in 45 cases with essential hypertension (EH). The results suggested that plasma CGRP level in patients with EH was lower than that in normal subjects (P less than 0.001). It was found that decrease of plasma CGRP was closely related with the severity of hypertension. However, the level of plasma atrial natriuretic factor (ANF) in EH patients was significantly increased as compared with normal subjects (P less than 0.01). A negative correlation between plasma CGRP and ANF (r = -0.3615, P less than 0.02) was found. These data suggested that decrease of plasma CGRP may play an important role in the pathogenesis of hypertension.

[A novel group of nucleolar organizer region associating proteins]

With the scleroderma autoantinucleolar antiserum which was discribed in our previous paper, we identified a novel group of nucleolar organizer associating proteins, ANOP. By means of immunoblotting, it was found that ANOP mainly consists of three polypeptides with molecular weights of 65, 76, and 78 KD respectively. Immunoelectron microscopy demonstrated that ANOP is localized in the shells of dense fibril components surrounding fibrillar centers of nucleolus. Moreover, indirect immunofluorescence studies on various cells of vertebrate animals indicated that ANOP is a group of highly conserved nucleolar antigens. The fibrillar centers of human, mouse, chinese hamster, chicken, frog and crucian carp cells can all be brightly stained by ANOP specific antiserum. However, it was found that in amphibian, the erythrocytes and the early embryo cells prior to gastrulation are devoid of ANOP. During gastrulation, ANOP begins to appear in the nuclei, and then, the content of ANOP in nucleoli apparently increases gradually. These phenomena suggest that ANOP may take a role in rRNA gene activity.

[Comparative studies on the component contents of shensuyin in the form of bag, pill and decoction]

The water extract, sugar and total volatile oil of Shensuyin have been determined and compared in the form of bag, pill and decoction. The volatile oil constituents have been analysed preliminarily by GC, thus providing an experimental basis for improving the preparation of the drug and controlling the quality.

[Relationship between hepatolithiasis and M phi, T cell subgroup reaction in the liver]

T Lymphocyte subpopulation and monocyte in the liver of 24 patients with hepatolithiasis were studied by ABC technique. It was found that there was a marked increase of the population of OKT8 and M phi positive cells in portal triads, and the ratio of OKT4 positive cells (helper/inducer T cells) to OKT8 positive cells (suppressor/cytotoxic T cells) was also higher than that in normal livers. T cells surrounding small bile ducts mainly had T4 phenotype, where as T8 cells seemed to predominate in small necrotic foci T8 cells in piecemeal necrotic foci were responsible for hepatocellular damage. These results suggest that in hepatolithiasis there was an enhancement of local cell immunoreaction and an imbalance of hepatic immunoregulatory T cells.

[Observation of efficacy of different dialytic therapies in renal transplantation preparation]

Fifty-seven cadaveric renal transplantations in fifty-five cases were analysed of them, thirty cases were prepared by continuous ambulatory peritoneal dialysis (CAPD group); twenty-seven transplantations in twenty-five cases were prepared by hemodialysis (HD group). Our data show that there is no significant difference in the survival duration between CAPD group and HD group; that there is also no significant difference in the survival duration between the two groups treated with the same immunosuppressive drugs, and that patients prepared by CAPD have a low risk of peritonitis after transplantation. It is better not to remove the Tenckhoff catheter until the graft function is stable so that it can be used for the transient peritoneal dialysis in the case of the insult of graft function or for the sampling of the peritoneal effusion for diagnosis of suspectable peritonitis after renal transplantation.