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81.
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Immunization of mice with a synthetic GM3-lactam-BSA (bovine serum albumin) conjugate (designed to emulate the corresponding natural GM3-lactone conjugate), followed by fusion of splenocytes with myeloma cells, gave rise to more than 300 monoclonal hybridomas producing antibodies to GM3-lactam-BSA, which did not react with Glc-BSA and BSA. Eight antibody clones were randomly chosen from the positive 300 hybridomas. The eight clones, all belonging to the IgG class, were unreactive against GM3-ganglioside, whereas two antibodies (P5-1 and P5-3, both IgG1, ) reacted with GM3-ganglioside lactone. Binding of these two antibodies to the GM3-lactam-BSA conjugate was inhibited by soluble glycosides of GM2-, GM3-, and GM4-lactam and by GM3- and GM4-lactam, respectively, but not by Gb3 or asialo-GM1 and GM2-saccharides. A third antibody (P3; IgG2b, ) was inhibited by GM2-, GM3-, and GM4-lactam, but did not recognize GM3-ganglioside lactone.  相似文献   
84.
The aim of this study was to clarify whether or not arachidonic acid metabolic disorders are caused by a substrate inavailability and whether such disorders might contribute to circulatory disturbances in the diabetic myocardium. Norepinephrine induced a decrease in the conductivity of both coronary arterial bed and myocardial microcirculation in alloxan-diabetic dogs. It was markedly (p < 0.05) attenuated both by indomethacin and acetylsalicylic acid pretreatments indicating an imbalance among the vasoactive prostanoids in diabetes. TXA2 release from the diabetic coronary rings was found to be elevated and could be normalized after the blockade of vascular adrenoceptors by phentolamine (p < 0.05). PGIZ synthesis was also enhanced by adrenergic blockade in the diabetic arterial rings. After pretreatment with l4C arachidonic acid, in order to measure substrate availability, the arachidonic acid metabolic rate was less in the diabetic coronary arteries than in healthy vessels (p < 0.05). Ten µmol/1 norepinephrine decreased arachidonic acid metabolism in the presence of prelabelled substrate in the diabetic animals, compared to an increase observed in metabolically healthy dogs. Therefore diabetes appears to diminish arachidonic acid metabolism and uptake independent of adrenoceptors and to induce an imbalance between vasoconstrictor and vasodilator cyclooxygenase products, resulting in elevated TXA2 release controlled by adrenergic mechanisms which may contribute to an impairment in myocardial microcirculation.Abbreviations 6-oxo-PGF1 6-oxo prostaglandin F1 - HPLC High Pressure Liquid Chromatograph - LAD Left Anterior Descending (coronary artery) - PGI2 Prostacyclin - TXA2 Thromboxane  相似文献   
85.
Summary Multiple endocrine neoplasia type 1 (MEN1) is characterized by neoplasia of the parathyroids, the pancreas, and the pituitary. Tumorigenesis involves unmasking of a recessive mutation at the MEN1 locus, which has been mapped to the centromeric part of chromosomal region 11q. In order to localize the MEN1 gene further and to make its isolation possible, a number of new markers were isolated. Two radiation-reduced somatic cell hybrids were identified that only contained markers close to and flanking the MEN1 region. DNA from these hybrids was used for the construction of a cosmid library, and clones containing human inserts were isolated. In addition, cosmid clones were isolated for locus expansion of 7 other markers that were mapped to the 11q12–13.2 region. The 33 newly isolated clones together with 25 previously published markers from this region were analyzed in a panel of radiation-reduced somatic cell hybrids. From the hybridization pattern, the region was divided into 11 parts. New restriction fragment length polymorphisms were identified in 7 of the newly isolated cosmid clones and in one plasmid. These were then used to sublocalize meiotic cross-overs more precisely in two MEN1 families, thus refining the mapping of the disease gene.  相似文献   
86.
Summary In the superposition eyes of the sphingid moth Deilephila and the neuropteran Ascalaphus, adjustment to different intensities is subserved by longitudinal migrations of screening pigment in specialized pigment cells. Using ophthalmoscopic techniques we have localized the light-sensitive trigger that controls pigment position.In both species, local illumination of a small spot anywhere within the eye glow of a dark-adapted eye evokes local light adaptation in the ommatidia whose facets receive the light. Details of the response pattern demonstrate that a distal light-sensitive trigger is located axially in the ommatidium, just beneath the crystalline cone, and extends with less sensitivity deep into the clear zone. The distal trigger in Deilephila was shown to be predominantly UV sensitive, and a UV-absorbing structure, presumably the distal trigger, was observed near the proximal tip of the crystalline cone.In Ascalaphus we also found another trigger located more proximally, which causes local pigment reaction in the ommatidia whose rhabdoms are illuminated (the centre of the eye glow). The light-sensitive trigger for this response appears to be the rhabdom itself.  相似文献   
87.
88.
Summary The sperm chromosomes of a man heterozygous for inv(20)(p13q11.2) were analyzed. Twenty-six sperm chromosome complements were examined, of which fourteen contained the normal chromosome, and twelve the inverted chromosome. None of the sperm complements contained a recombinant chromosome 20. The frequency of structural chromosomal aberrations unrelated to the inversion was 11.5% (3/26). Numerical aberrations were not observed. The percentages of X- and Y-bearing sperm were 56% and 44%, respectively, which was similar to the expected 11 ratio.  相似文献   
89.
Summary Twenty-five patients with von Willebrand's disease (vWD) type III were analysed with regard to blood coagulation variables and possible deletions. Nine of the probands and their families were further investigated with DNA linkage analyses. Different patterns of heredity can be suggested in our families with vWD type III, on the basis of blood coagulation analyses. The findings suggest homozygosity in five families and the possibility of compound heterozygosity or a new mutation in the proband in three families. The linkage analyses confirm the results of the coagulation analyses. The segregation of the von Willebrand factor (vWF) gene can be followed in the families, and carrier diagnosis can be made in several of the probands' relatives. The possibility of large deletions in the vWF gene of the probands and their parents was investigated with probes representing the whole vWF cDNA. No deletions were found.This study was approved by the Ethics Committee of the Karolinska Hospital (No. 84:1)  相似文献   
90.
The immune system furnishes the organism with the utmost effective defence mechanisms against foreign and changes in self without doing self-harm. However, optimized efficacy in the defence against the immense variety of foreign antigens generates a higher risk for inadvertent self challenge. Such inherent short-comings are the inevitable burden traded for the benefits of an optimally organized defence system. The central molecules involved in specific immune reactions include antigen receptors of B and T lymphocytes, and antigen-presenting proteins encoded by the major histocompatibility complex (MHC; in man HLA). The genetics and evolution of these multigene families is discussed here with respect to their potential contributions to disturbances of self recognition. Simple molecular biological tools and procedures for efficiently screening the immunologically relevant genes are described.Dedicated to Professor Dr. U. Wolf on the occasion of his 60th birthday  相似文献   
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