滋阴药延缓衰老机制的研究进展＊

当代社会，老年人口比例呈现不断上升的趋势，老龄化问题日益严峻。因此，如何有效地延缓衰老不仅成为了世界医学研究的热点，也成为了全球亟待解决的问题。中医药在延缓衰老方面经验丰富，而滋阴药在此类研究中效果显著。本文通过整理滋阴药抗衰老作用机制的若干文献，对滋阴复方六味地黄丸、二至丸、左归丸及其他滋阴中药延缓衰老的机制研究进展进行综述。     

Coats plus syndrome (cerebroretinal microangiopathy with calcifications and cysts‐1): A case report

We present a 6‐year‐old girl with skin hyperpigmentation, leukoplakia, and onychodystrophy, the classic mucocutaneous triad usually associated with dyskeratosis congenita. The patient also had premature graying of the hair, bone marrow failure, hepatitis, exudative retinopathy, osteopenia with multiple long bone fractures, and intracranial calcifications and brain cysts. Coats plus syndrome is a rare disease with a clinical and genetic overlap with dyskeratosis congenita. This disease is reviewed, with a focus on the pathogenesis of the genetic anomalies and its background as a telomere biology disorder.     

常见植物药对结肠癌的防治作用及其作用机制

植物药对结肠癌具有良好的防治作用。姜黄素、多糖(苹果多糖、香菇多糖)、皂苷(重楼皂苷、人参皂苷)、白藜芦醇、槲皮素等植物药可通过不同信号通路抑制结肠癌细胞的增殖,促进细胞凋亡。此外,植物药还具有抗炎、抗氧化、抗血管生成、减轻化疗药物不良反应、逆转肿瘤细胞耐药等作用。了解植物药对结肠癌的防治作用及其可能的作用机制,能为结肠癌的临床防治提供更多的理论依据及治疗思路。     

Mechanisms mediating the brain stem control of somatosensory transmission in the dorsal horn of the cat's spinal cord: an intracellular analysis

Summary The effect of brainstem stimulation was studied on neurones recorded intracellularly in the superficial and deeper laminae of the lumbosacral dorsal horn of the spinal cord in anaesthetised cats. Stimulation in the nucleus locus coeruleus (LC) produced a hyperpolarisation in 4/13 multireceptive neurones and produced a biphasic action consisting of a hyperpolarisation which was followed by a depolarisation in 3/13 neurones. These actions were produced irrespective of whether the multireceptive neurone was located in the superficial or deeper laminae of the dorsal horn. Stimulation failed to produce postsynaptic potentials in the remaining 6/13 multireceptive neurones. The amplitude of hyperpolarisation was increased by the passage of depolarising pulses through the recording microelectrode and decreased by hyperpolarising pulses. Stimulation in other brainstem areas such as, the lateral (FTL), paralemniscal (FTP) and central (FTC) divisions of the tegmental field and the nuclei raphe magnus (NRM) and reticularis magnocellularis (RMc) also hyperpolarised neurones in the dorsal horn. The polarity of hyperpolarisation evoked from some brainstem areas (FTP, FTC, RMc) could be reversed to depolarisation by the passive diffusion of ions from the recording microelectrode containing 3M-KCl. Brainstem (LC, NRM, FTP, FTL) stimulation generated long lasting (700 ms) hyperpolarisation on 4/4 selectively nocireceptive neurones of lamina I. There was, however, no effect on the activity of 5/5 neurones recorded in laminae I/II which in addition to receiving excitatory cutaneous inputs were inhibited by heat stimuli. Stimulation in LC also produced dorsal root potentials (DRPs) and reduced the amplitude of simultaneously recorded excitatory postsynaptic potentials (EPSPs) generated by the activation of primary afferent fibres in 3 multireceptive neurones. It is concluded that inhibition of nociceptive transmission in the spinal cord from LC and other brainstem areas may involve both pre- and postsynaptic mechanisms.     

The nature of polymorphism of the HLA-DRB intron sequences is lineage specific

Abstract: The sequence database of HLA-DRB genes is mainly derived from mRNA analysis or has focused exclusively on the polymorphism of the 2nd exon. Little is known about the non-coding sequences of the different DRB alleles which represent about 94% of the genes. In this study we have determined the sequence of the 3' 500 bp intron 1 fragment adjacent to exon 2 in all serologically defined HLA-DRB genes and their most frequent allelic subtypes. The intron sequences turned out to be highly polymorphic. Similar to the class I introns, this variability was not characterized by random point mutations but by a highly systematic diversity reflecting the lineage-specific relationship of the HLA-DR alleles. With a few exceptions in DRB1*15, 13 and 08 as well as DRB 4 and 5, the variability mirrors the serological diversity. As well as delivering insight into the genetic relationship between the different DRB alleles, these sequences will provide an extremely valuable basis for developing advanced DRB sequencing strategies for clinical purposes.     

Cellular distribution of the iron-binding protein lactotransferrin in the mesencephalon of Parkinson’s disease cases

Changes in the distribution of the iron-binding protein lactotransferrin have recently been described in the central nervous system during a variety of neurodegenerative disorders. To investigate whether lactotransferrin is associated with the neuropathological changes that characterize Parkinson’s disease, we analyzed the distribution of this protein in the mesencephalon of neurologically normal individuals and patients affected with Parkinson’s disease using quantitative immunohistochemical methods. High levels of lactotransferrin were observed in a large population of neurons in the substantia nigra of control cases. Lactotransferrin-positive neurons were severely affected by the neurodegenerative process that occurs in Parkinson’s disease as indicated by a severe decrease in the number of immunolabeled neurons in all of these cases. Quantitative analysis also demonstrated higher immunolabeling levels of lactotransferrin in the surviving neurons in the substantia nigra and ventral tegmental area of Parkinson’s disease cases compared to control cases. These results suggest that lactotransferrin may participate actively in the mechanism of neuronal degeneration in Parkinson’s disease. Received: 16 October 1995 / Revised, accepted: 1 December 1995