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1.
The premenstrual syndrome has been described briefly and the literature relating to its pathophysiology and treatment have been reviewed. The great number of theories as to etiology and many different kinds of treatments attest to our ignorance of the exact nature of this problem. Although it is obvious that the hypothalamo-pituitary-ovarian axis must be involved, the exact mechanism whereby the symptoms come about remains elusive. Progestin in the presence of estrogen appears to be essential. Excess estrogen may aggravate the condition. The popular theory of progesterone deficiency has not been supported by double blind trials of progesterone in various forms versus placebo. Because of the important placebo effect in this condition, double blind trials are essential in the assessment of any form of treatment.  相似文献   
2.
We have investigated the characteristics of platelet-activating factor (PAF)-stimulated protein tyrosine phosphorylation in rabbit platelets and its relationship to pp60c-src. 32P-Labeled platelets were challenged with PAF (10(-7) M) for 15 s, the reaction was killed by lysis at 4 degrees C, and samples were loaded onto a phosphotyrosine monoclonal antibody (Tyr(P)-mAb)-agarose column. The column was eluted with 10 mM phenyl phosphate, and the fractions were collected. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by autoradiography of the column fractions, showed that PAF increased the radioactivity of about a dozen protein bands with predominant ones of approximate molecular masses of 50, 60, 71, 82, and 300 kDa. When Tyr(P)-mAb-agarose column fractions were subjected to immunoblotting with pp60v-src mAb, it was observed that PAF treatment increased the reactivity of 50- and 60-kDa protein species. Immunoprecipitation with pp60v-src mAb further confirmed that PAF treatment increased phosphorylation of the 60- and 50-kDa proteins. Polyclonal antibody to G-protein (alpha-subunit) did not exhibit any reactivity to the column fractions and thus ruled out this protein as substrate for the tyrosine kinase. We next attempted to localize the pp60c-src. Platelet membrane particulate and cytosol fractions were separated from control and PAF-treated platelets, and it was observed that the immunoreactivity to pp60v-src mAb dramatically increased in the particulate membrane fraction from PAF-treated platelets. A concomitant decrease in the immunoreactivity in the cytosol fraction of PAF-treated platelets was also noted. It is concluded that PAF stimulates phosphorylation of pp60c-src tyrosine kinase and causes its rapid translocation from cytosol to membranes in rabbit platelets.  相似文献   
3.
The karyomorphology of Podophyllum hexandrum Royle (2n=2x=12) is described for the first time. The haploid set comprises one metacentric, three sub-metacentric and two acrocentric chromosomes. Metacentrics are the longest and acrocentrics the smallest in the complement. Secondary constrictions are located in the short arm of two meta-/submetacentrics and in the long arm of the two acrocentric chromosomes. The number of NORs is in agreement with the number of nucleoli organized per root tip nucleus.  相似文献   
4.
Summary In the progenies of the crosses between disomics and trisomies, two plants were isolated which carried an extra chromosome that was unlike any in the standard complement. The plants were not alike; while one carried a metacentric, the other had a telocentric extra chromosome. Their detailed structure and possible modes of origin are discussed.  相似文献   
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6.
Systems biology is an approach to explain the behaviour of a system in relation to its individual components. Synthetic biology uses key hierarchical and modular concepts of systems biology to engineer novel biological systems. In my opinion the next step in biology is to use molecule-to-phenotype data using these approaches and integrate them in the form a periodic table. A periodic table in biology would provide chassis to classify, systematize and compare diversity of component properties vis-a-vis system behaviour. Using periodic table it could be possible to compute higher-level interactions from component properties. This paper examines the concept of building a bio-periodic table using protein fold as the fundamental unit.  相似文献   
7.
It is well established that plasmids are involved in the expression of lipopolysaccharide in certain species of Shigella. In Shigella sonnei, both the biosynthesis of oligosaccharide side chains (O antigen), and cell invasiveness are controlled exclusively by a 120 megadalton (MDa) plasmid. In Shigella dysenteriae 1, a 10 kilobase (kb) plasmid is required for O-antigen production. Shigella dysenteriae 1 strains devoid of this plasmid lose the ability to synthesize O antigen. Interestingly, this 10-kb plasmid is not stably maintained in Escherichia coli K-12 strains, where it is lost spontaneously at a high frequency. Our genetic analyses of Shigella dysenteriae 1 strain IDBM11 and its derivatives indicate that the stability of this plasmid is associated with the histidine region of the chromosome which is unique to Shigella dysenteriae. Furthermore, the 10-kb plasmid is stably maintained in wild-type IDBM11 with an intact histidine locus. However, this plasmid is not stable in IDBM11 derivatives (e.g., IDBM11-1 and IDBM11-2), in which the his locus has been substituted with the histidine region of an E. coli K-12 chromosome. The S. dysenteriae IDBM11 strain, and its derivatives (lacking a 10-kb plasmid), displayed an invasive property as demonstrated by their internalization by HeLa cells in an in vitro assay. Thus the 10-kb plasmid of Shigella dysenteriae 1 is required for O-antigen synthesis but not for cell invasion.  相似文献   
8.
While progesterone metabolites have long been known to be potent anesthetics in pharmacological doses, there is no available information as to their effects on behaviour at physiological levels. In this study, 5 alpha- and 5 beta-pregnanediones in silastic capsules were implanted in ovariectomized rats. Approximately 4 mg/kg/day was absorbed over a 24-day period. Rats receiving 5 beta-pregnanedione had decreased motor activity (58% control, P less than or equal to 0.001) while those receiving the 5 alpha-isomer had increased activity (143% control, P = 0.01). These studies suggest that these progesterone metabolites may be responsible for some behavioural changes.  相似文献   
9.
The effect of new non-steroidal anti-inflammatory agents on lysosomal stability was studied by determining the activity of beta-glucuronidase, a typical lysosomal enzyme, in various sub-cellular fractions and its release from the lysosome-rich fraction. Adjuvant arthritic animals showed a significant increase in the beta-glucuronidase activity in sub-cellular fractions. The increased rate of the release of beta-glucuronidase from lysosome-rich fraction clearly suggested that arthritic syndrome caused decreased stability of the lysosomes. Administration of boswellic acids or salai-guggal to arthritic animals was found to increase the lysosomal stability by inhibiting the rate of release from lysosome-rich fraction and reducing beta-glucuronidase activity in various sub-cellular fractions. Of the two anti-inflammatory agents tested, salai-guggal was found to afford more therapeutic value than boswellic acids.  相似文献   
10.
Mutations in POLG account for one of the most frequent nuclear encoded causes of mitochondrial disorders to date. Individuals harboring POLG mutations exhibit fairly heterogeneous clinical presentations leading to increasing difficulties in classifying these patients into defined clinical phenotypes. This study aims to investigate the molecular basis of a mitochondrial cytopathy in a patient with 3-methylglutaconic aciduria and to expand the clinical phenotype associated with POLG mutations. Clinical, molecular and genetic analyses as well as neurophysiological examinations were carried out for a 23-year-old woman of mixed Caucasian and Latin American ancestry with a history of cataracts diagnosed at age 1 year, she had onset of distal muscle weakness at age 2 years progressing to atrophy and ovarian dysgenesis at puberty. The patient was found to have 3-methylglutaconic acid with normal 3 hydroxyisovaleric acid on urine organic acid analysis. POLG sequencing was done and a heterozygous variant, c.2851T>A (p.Y951N) was found which is predicted to be deleterious. There are limited reports of POLG mutations in individuals with 3-methylglutaconic aciduria. This case report of a young woman with a heterozygous mutation in POLG, presenting with muscle weakness and atrophy at a young age aims to aid clinicians in similar challenging diagnostic situations as well as enhances our understanding of POLG-related disease phenotypes.  相似文献   
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