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1.
The results of a detailed analysis of 100 supernumerary limbs generated by 180° ipsilateral rotation (on the same limb stump) of regeneration blastemas is presented. The limbs were analyzed in terms of their position of origin, frequency, cartilage structure by Victoria blue staining, and muscle structure by serial sections. Single, double, or triple supernumeraries can be produced at no unique position of origin, although the posterodorsal quadrant was preferred. Four classes of supernumerary limbs were generated by such operations—normal; double dorsal or double ventral; part normal/part mirror imaged; part normal/part inverted in approximately equal frequencies. After amputation of these supernumeraries the same muscle patterns are faithfully regenerated. A hypothesis to explain the production of these abnormal limbs is proposed based on the observed phenomenon of fusion of supernumerary blastemata, but their regenerative behaviour presents problems for current models of pattern formation. Similar results have been obtained with developing limb buds and the relation between development and regeneration is discussed. 相似文献
2.
Matthias Kirsch Mustafa B. A. Djamgoz Hans-Joachim Wagner 《Cell and tissue research》1990,260(1):123-130
Summary A negative feedback interaction between luminosity type horizonatal cells (HCs) and green-sensitive cones generates the long-wavelength-sensitive depolarizing response in biphasic chromaticity type HCs. This interaction is suppressed in the dark and is potentiated by light adaptation of the retina. HCs are morphologically plastic; during light adaptation, their dendritic terminals within cone pedicles extend, giving rise to spinules. This paper examines whether there is a quantitative correlation between the time course of light-dependent formation of the spinules and enhancement of the feedback interaction. The strength of the feedback interaction in isolated retinac of the roach was determined as the neutral wavelength at which reversal of spectral response polarity occurred in biphasic HCs. A good correlation was found between the neutral wavelength and the spinule/ribbon ratios of retinae. Biphasic HCs were intracellularly stained with horseradish peroxidase and the correlative ultrastructure of the contacted pedicles was examined. Neutral wavelength was found to be correlated with the spinule number, weighted according to the number of synaptic contacts mediating feed-forward transmission. The latter was estimated from the total number of labelled Cb/H2 HC processes (central and lateral) at synaptic triads. A model in which spinules mediate the negative feedback interaction of HCs in the retina of cyprinid fish is presented. 相似文献
3.
Mustafa Özilgen 《Applied microbiology and biotechnology》1988,29(6):536-543
Summary Large amounts of data indicated that most of the metabolic processes of the acidogenic (acid producing) and the solventogenic (solvent producing) fermentations were regulated by product accumulation. A simple unstructured model simulated microbial growth, product formation and substrate utilization in six different fermentations, where five different microorganisms produced various combinations of ten different products. Specific growth rates of these microorganisms decreased proportionally with overall product accumulation. The products were excreted in non-growth associated pattern. Excretion of some of these products were inhibited by the overall product accumulation similarly as the microbial growth. A substrate consumption model which considered the biomass and individually all the products as separate substrate sinks simulated the data satisfactorily. 相似文献
4.
A protein antigen of Mycobacterium leprae is related to a family of small heat shock proteins. 总被引:15,自引:4,他引:11 下载免费PDF全文
A H Nerland A S Mustafa D Sweetser T Godal R A Young 《Journal of bacteriology》1988,170(12):5919-5921
The gene encoding an immunologically important 18-kilodalton protein antigen of Mycobacterium leprae has been sequenced, and the amino acid sequence of the antigen has been deduced. The 18-kilodalton antigen is strikingly similar in size and sequence to a family of eucaryotic heat shock proteins. 相似文献
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7.
S J Mustafa M M Mansour 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1984,176(1):22-26
This study was undertaken in an attempt to further understand the relationship between adenosine and H+ ion. Using Langendorff hearts from male rabbits, the perfusion fluid pH was lowered from 7.4 to 7.1 and 6.8 with CO2. A 31 and 86% increase in coronary flow with a simultaneous increase in the release of adenosine by 61 and 128% was observed at pH 7.1 and 6.8, respectively. A direct relationship between adenosine release and coronary flow with a correlation coefficient of 0.99 was found at pH values of 7.4, 7.1, and 6.8. The degradation products of adenosine namely inosine and hypoxanthine were unchanged at 7.1 and 6.8 from 7.4. These data support a role for adenosine in the regulation of coronary flow and suggest a relationship between adenosine and H+ ion. 相似文献
8.
Nabil Elsayed Allen Hacker Mohammad Mustafa Klaus Kuehn Gerhard Schrauzer 《Biochemical and biophysical research communications》1982,104(2):564-569
The effects of reducing glutathione peroxidase activity in the lung by changing dietary selenium intake has been investigated. In animals that were exposed to room air, selenium effects were confined to glutathione peroxidase activity, whereas under conditions of oxidant stress (ozone) the decrease in glutathione peroxidase activity prevented the stimulation of the pentose phosphate cycle (assayed by measuring glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities) which has been reported to increase in response to oxidant stress. The suppression of glutathione peroxidase activity was found to depend on dietary selenium concentration. The physiological significance of this observation may be related to the process of injury and repair in the lung. 相似文献
9.
Transient receptor potential ion channel melastatin subtype 8 (TRPM8) is activated by cold temperature and cooling agents,
such as menthol and icilin. Compounds containing peppermint are reported to reduce symptoms of environmental cold stress such
as cold allodynia in dorsal root ganglion (DRG) neuron; however, the underlying mechanisms of action are unclear. We tested
the effects of physiological heat (37°C), anthralic acid (ACA and 0.025 mM), 2-aminoethyl diphenylborinate (2-APB and 0.05)
on noxious cold (10°C) and menthol (0.1 mM)-induced TRPM8 cation channel currents in the DRG neurons of rats. DRG neurons
were freshly isolated from rats. In whole-cell patch clamp experiments, TRPM8 currents were consistently induced by noxious
cold or menthol. TRPM8 channels current densities of the neurons were higher in cold and menthol groups than in control. When
the physiological heat is introduced by chamber TRPM8 channel currents were inhibited by the heat. Noxious cold-induced Ca2+ gates were blocked by the ACA although menthol-induced TRPM8 currents were not blocked by ACA and 2-APB. In conclusion, the
results suggested that activation of TRPM8 either by menthol or nociceptive cold can activate TRPM8 channels although we observed
the protective role of heat, ACA and 2-APB through a TRPM8 channel in nociceptive cold-activated DRG neurons. Since cold allodynia
is a common feature of neuropathic pain and diseases of sensory neuron, our findings are relevant to the etiology of neuropathology
in DRG neurons. 相似文献
10.