人类活动影响下新疆生态环境的一些变化

人类活动引起的新疆生态环境变化主要有以下几方面:1.河流流程缩短,河水矿化度和泥沙含量增加;2.湖泊水位下降,湖面缩小或变干,湖水矿化度升高;3.森林破坏,面积缩小;4.草场的产草量降低,牧草质量下降; 5.土壤次生盐渍化、沼泽化和肥力下降;6.土地沙漠化不断扩大。     

Imaging erythrocytes under physiological conditions by atomic force microscopy

Since its invention in the mid 1980s atomic force microscopy has revolutionised the way in which surfaces can be imaged. Close to atomic resolution has been achieved for some materials and numerous images of molecules on surfaces have been recorded. Atomic force microscopy has also been of benefit to biology where protein molecules on surfaces have been studied and even whole cells have been investigated. Here we report a study of red blood cells which have been imaged in a physiological medium. At high resolution, the underlying cytoskeleton of the blood cell has been resolved and flaws in the cytoskeleton structure may be observed. Comparison of the normal 'doughnut' shaped cells with swollen cells has been undertaken. Differences in both the global properties of the cells and in the local features in cytoskeleton structure have been observed.     

Synthesis, resolution and charge-donor properties of six tryptophan analogues.

In order to investigate the special function of tryptophan in peptide hormones, six tryptophan analogues have been synthesized, in which structural resemblance has been grossly retained and potentially essential properties have only partially been varied. The L-enantiomers have been isolated after enzymatic digestion of racemic dipeptide derivatives, and charge-transfer properties of the compounds have been studied.     

THE ACCUMULATION OF ELECTROLYTES : VII. ORGANIC ELECTROLYTES PART 2

Analyses have been made of the inorganic constituents of the juices expressed from the leaves of Rheum, Rumex, and Oxalis. It has been shown that in all cases there is a large excess of inorganic cations over anions in the sap, the average ratio of cations to anions being 3.8 (Part 1, p. 239). The ash analyses of plant tissues (chiefly leaves) reported in the literature have been examined critically, and it has been shown that the preponderance of inorganic cations over inorganic anions in the ash and in the sap is general. It has been concluded that the excess of inorganic cations is consistent with the view that cations pass into the protoplasm chiefly in the form of hydroxides, and are accumulated either in the form of organic salts (such as the oxalates) or in non-polar linkage. It has been concluded that practically all the potassium and sodium found in plant ash must have been present originally in the form of soluble ionogenic compounds, but that a considerable part of the calcium and magnesium may have been present originally in the form of insoluble salts or as components of non-polar compounds. The methods whereby the cations, particularly potassium, may have been accumulated have been discussed, and it has been concluded that as it does not seem very probable that they enter chiefly as nitrates or bicarbonates we may suppose that they go in to a large extent as hydrates: this is highly probable in the case which has been most carefully investigated (Valonia).     

Diagnosis of Helicobacter pylori

The different invasive and noninvasive diagnostic tests for Helicobacter pylori have been applied mainly in emerging countries. Molecular methods have been developed, especially a test for detection of H. pylori and its clarithromycin resistance directly from stools. The long-term effects of eradication on histologic lesions have been studied in a meta-analysis and the prognostic value of post-treatment in gastric mucosa-associated lymphoid tissue lymphoma has been assessed. An operating link for gastritis assessment (the OLGA staging) has also been published. Attempts to simplify the urea breath test protocol have been made, and new stool antigen tests have been proposed and compared to those previously available.     

Upper lobe lobectomy and concomitant thoracoplasty in pulmonary tuberculosis. A preliminary report

In this, a preliminary report, the advantages and disadvantages of upper lobe lobectomy and concomitant thoracoplasty in tuberculosis have been summarized. There has been no undue increase in the operative hazard, there have been no complications, and the immediate results have been entirely satisfactory.Twenty-six patients were subjected to a combined operation (17 upper lobectomy-thoracoplasty and nine pneumonectomy-thoracoplasty) with one postoperative death. Indications for primary lobectomy have been discussed. The technique of resection and concomitant thoracoplasty has been briefly described.     

Intermediate filament structure.

In the past year, several new developments concerning the structure of intermediate filament proteins and their assembly into intact intermediate filaments have been made: the coiled-coil structure of a rod domain has been elucidated; the basis of the chain interaction and its role in intermediate filament assembly has been specified; the organization of nearest-neighbour molecules in keratin intermediate filaments has been determined; and the glycine loop structures of the terminal domains of epidermal keratin chains have been defined. In addition, mutations in intermediate filament chains that promote pathology have been reported for the first time.     

Postoperative hypoparathyroidism: risk of complications]

For assessing the risk of adverse complications of surgery the group of 130 patients with post-operational hypoparathyroidism was analysed. Surgical hypoparathyroidism has been diagnosed in 51% of operated on thyroid gland patients. Laryngeal nerves have been damaged in 46.6% of patients. The injury to laryngeal nerves has been irreversible in 2/3 of patients, and reversible in the remaining 1/3. Cataract, nephrolithiasis and vitamin D3 intoxication have been observed in some cases before surgery. Their incidence increased in severe surgical hypoparathyroidism. Osteoporosis of the spine has been diagnosed in 49% of patients including some with vertebral fractures. No correlation between the degree of spine osteoporosis and diagnosis before surgery, number of operations on thyroid gland, and type of therapy has been noted. The symptoms of hypercalcemia have been diagnosed in 5 patients out of which hypercalcemia has been transient in 2 patients, and lasted for 1-5 months in the remaining 3 patients. The results of 7,873 analyses of mineral metabolism have been assessed. Hypocalcemia has been found in 38.4%, hypercalcemia in 1.6%, hypomagnesemia in 25.7%, hyperphosphatemia in 41.5%, decreased alkaline phosphatase serum activity in 28.7%, and hypercalciuria in 22.4% of cases. Surgical hypoparathyroidism is frequently accompanied by surgical hypothyroidism and injury to the recurrent laryngeal nerves.     

Photomyoclonic seizures in the baboon, Papio papio.

The inborn seizure response of Papio papio to intermittent light stimulation has been reviewed as a model of human epilepsy. The electrographic and clinical features have been described and useful methodology has been outlined. A diurnal cyclicity in seizure responsiveness has been described with greatest seizure severity at 8 AM in parallel with a rise in urinary output of cortisol. Hormonal influences on the seizure response have been described for ethinyl estradiol, thyroxin, and triiodothyronine. Evidence regarding neurotransmitter involvement has been reviewed. Data regarding use of the animal for anticonvulsant testing in single and chronic doses has been discussed. Particular advantages of the model for study of age-related drug effects and the assessment of the effects of chronically administered anticonvulsant agents on learning and memory have been described.     

Zinc level in the blood of children with nephrotic syndrome and correction of its deficiency with animal blood preparation Livex]

Serum and erythrocyte zinc levels have been assayed in in 45 children with steroid-dependent nephrotic syndrome in both acute phase and remission. Out of these children a group of 22 has been distinguished. These patients have been treated with Livex--animal blood preparation containing amino acids and trace elements, including zinc. It was found, that serum zinc has been significantly lowered in children with the acute phase of nephrotic syndrome who were not treated with Livex. Erythrocyte zinc levels have been normal in these patients. A significant increase in both serum and erythrocyte zinc levels has been noted during remission, but they have still been lower that in healthy children. A three-month cure with Livex produced statistically significant increase in zinc levels in children during remission.     

Prevalence of HIV antigens in cerebrospinal fluid and in serum of patients with both asymptomatic and symptomatic HIV infection]

Prevalence of HIV-Ag in both serum and CSF has been determined in 19 HIV infected patients, including 7 patients without any symptoms or only generalized lymphadenopathy, 5 patients with ARC and 7 patients with AIDS. The results have been correlated with clinically evident neurological disorders. HIV-Ag have been detected in 9 out of 12 patients with ARC (AIDS Related Complex) and AIDS. In 8 of them neurological disorders have been present. Out of the remaining 7 patients in only one HIV-Ag has been detected in CSF (p < 025). No correlation between the presence of HIV antigen in CSF and serum has been noted.     

Cytosolic and non-cytosolic carbonic anhydrase enzymes from bovine leukocytes.

In this study, carbonic anhydrase (CA) enzyme has been purified and separately characterized according to bound form in 4 steps as outer peripheral, cytosolic, inner peripheral, and integral from bovine leukocyte. Affinity chromatography has also been used for purification of the enzyme in four steps. CA has been found for each step. Measurment of enzyme activity has been done by CO2 hydratase activity and esterase activity methods. Optimum pH and optimum temperature have been defined for each step of purified enzyme. The behaviors of CA with specific inhibitors, such as KSCN and NaN3 have been investigated. In each step, molecular weight and purity have been determined by gel filtration and SDS-PAGE electrophoresis. In addition, enzyme K(M) and Vmax values have been determined with the method of Lineweaver-Burk.     

Upper Lobe Lobectomy and Concomitant Thoracoplasty in Pulmonary Tuberculosis—A Preliminary Report

In this, a preliminary report, the advantages and disadvantages of upper lobe lobectomy and concomitant thoracoplasty in tuberculosis have been summarized. There has been no undue increase in the operative hazard, there have been no complications, and the immediate results have been entirely satisfactory.Twenty-six patients were subjected to a combined operation (17 upper lobectomy-thoracoplasty and nine pneumonectomy-thoracoplasty) with one postoperative death.Indications for primary lobectomy have been discussed.The technique of resection and concomitant thoracoplasty has been briefly described.     

Uridine insertion/deletion RNA editing in trypanosome mitochondria: a complex business

The basic mechanism of uridine insertion/deletion RNA editing in mitochondria of kinetoplastid protists has been established for some time but the molecular details remained largely unknown. Recently, there has been significant progress in defining the molecular components of the editing reaction. A number of factors have been isolated from trypanosome mitochondria, some of which have been definitely implicated in the uridine insertion/deletion RNA editing reaction and others of which have been circumstantially implicated. Several protein complexes have been isolated which exhibit some editing activities, and the macromolecular organization of these complexes is being analyzed. In addition, there have been several important technical advances in the in vitro analysis of editing. In this review we critically examine the various factors and complexes proposed to be involved in RNA editing.     

Studies on the Chemical Components of Oxytropis ochrocephala Bunge

Oxytropis ochrocephala Bunge has been characterized as one of the most destructive plants to livestock in the North-Western China. Its chemical components have not been studied. We have been isolated four flavonoids from the aerial parts of Oxytropis ochrocephala Bunge. They have been identified as quercetin, rhamnocitrin, isoquercitrin and rhamnocitrin-3-glucoside by UV, IR, 1HNMR and MS spectra of these flavonoids. Their acetyl derivatives have been prepared and their 1HNMR and MS spectra are fully in accord with this conclusion. The rhamnocitrin-3-glucoside has been found first of all in Oxytropis species. It is perhaps valuable for chemotaxonomy of Oxytropis genus.     

Circadian rhythmicity of prolactin secretion in Huntington's chorea

Prolactin circadian secretion has been studied in 16 males and in 8 females with Huntington's Chorea, in order to evaluate changes of the hormone's titres and of their periodicity in a condition where alterations of neurotransmission have been documented. Prolactin levels have been found normal, enhanced and low levels have been observed in one male case. Sleep connected surge has been found to be present in all cases. A harmonic analysis of periodical changes has been performed by a Fourier's cosines series. The changes in the occurence of different harmonic frequencies in respect to normal controls are not significant. No correlation could be drawn among clinical indices, hormone levels and the feature of the occurring harmonics.     

Measurement and study of the nose and face and their correlations in the young adult of Han nationality

The measurement of 13 items in the face and nose of 220 young adults (110 males and 110 females) of the Han nationality between the ages of 18 and 21 years has been done in the Henan Province of China. The means and standard deviations have been obtained, and the significant differences in many items between males and females have been proved. Some items influencing outer nasal shape have been analyzed. The correlations between nose height, nose length, and morphologic facial height and physiognomic facial height have been discussed. The ratio and amount of nasal breadth to facial breadth and nasal breadth to interocular breadth have been compared and analyzed, and the differences among the different races and between the sexes have been explained.     

QT/QS2 index in patients with arterial hypertension, mitral valve prolapse and hyperthyroidism]

QT/QS2 ratio has been assessed in 26 patients with both borderline and mild hypertension and mitral valve prolapse syndrome (19 patients), and hyperthyroidism (16 patients) in comparison with method control groups. The following polycardiographic parameters have been analyzed: QT, QTp, QS2, QT/QS2, and QTp/QS2. Higher values of QT/QS2 ratio have been noted in patients with mitral valve prolapse syndrome and hyperthyroidism than that in the control group. There has been no difference in patients with mild hypertension while the values of the analyzed parameter have been significantly lower in patients with borderline hypertension. QT has been longer than QS2 (QT)QS2 1/in 9 (56%) patients with hyperthyroidism. A positive correlation between QT/QS2 ratio and ++thyroxine levels have been noted in these patients. QT values have been higher than QS2 values only in 1 patient with mild hypertension. It seems that QT/QS2 value has limited value as an indirect index of the adrenergic activity in the dysfunction of the autonomic nervous system.     

Sedimentation equilibrium of proteins in density gradients.

The technique of sedimentation equilibrium in density gradients in the analytical ultracentrifuge has been applied to the study of proteins. A variety of effects and procedures including the use of density marker beads, the effects of pressure on buoyant density and pH, and the calculation of compositional density gradient proportionality constants and density--refractive index relations have been developed. The buoyant densities of twenty-four proteins have been measured and hydration values computed. The buoyant titrations of six proteins have been measured. These data have been interpreted in terms of the buoyant titrations which have been obtained for six ionizable homopolypeptides, five copolypeptides, two non-ionizable homopolypeptides and three chemically modified proteins. Spectropolarimetry and potentiometric titrations were employed to further interpret these data. Approximate values for dissociation constants, numbers of ionizable residues, and the nature of ions bound or dissociated upon ionization have been obtained. The relation between potentiometric and buoyant titrations and the use of density gradient centrifugation as a probe for protein structure have been explored.