[病理讀書會]第一章3/3, 細胞,組織的變化/老化

看板Medicine (醫學生物)作者HIbaby (燃燒吧! 嗨~北鼻!)時間16年前 (2008/06/06 11:26)推噓0(0推 0噓 0→)

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接下來要看得是最後的部份, 要看細胞受傷後細胞內的反應細胞間的一些堆積疾病引起的鈣還有細胞的老化 ------------------------------------- 細胞內的變化 LYSOSOMAL CATABOLISM lysosome會分解一些物質,透過下面兩種形式 Heterophagy : 分解由endocytosis吞入的一些東西 Autophagy: 分解細胞內部自己的東西. 雖然lysosome有許多酵素可以分解東西,但非萬能有些東西無法分解,則會造成lysosome堆積, 有些藥物也會造成lysosome pH值上升,導致lysosome功能異常 INDUCTION (HYPERTROPHY) OF SMOOTH ENDOPLASMIC RETICULUM sER是有一些分解毒物酵素所在地,所以細胞受到毒害, 這邊也是挺忙的 MITOCHONDRIAL ALTERATIONS mit.在細胞受傷或是死亡中扮演重要角色在壓力下 number, size, and shape of mitochondria都會改變 CYTOSKELETAL ABNORMALITIES 細胞骨架失常後,會影響細胞的運動,也在細胞內堆積一些骨架原料除此之外, 像是Thin filaments受損,也會影響一些蛋白質的調節 ---------------- 接下來談細胞間的一些堆積 Intracellular Accumulations 正常細胞會堆積一些water, lipids, proteins, and carbohydrates 而不正常的細胞會作些 abnormal synthesis or metabolism 所產生的東西和pigment Lipid堆積許多種類的脂質都可以堆積, 例如CCl4等傷害肝臟後,造成 triglyceride 堆積形態上, 在肝臟和心臟常出現 fatty change, 而造成在肝細胞(實質) 內出現泡狀油滴.這類可以用Red-O染色染出. 肝臟堆積lipid, 會大到3-6kg, 且呈現黃色(脂肪肝) 油滴堆積在心肌細胞, 則會出現small droplets.常由缺氧或是心肌炎導致另外, 膽固醇堆積也常在動脈硬化, 黃疸, 發炎等疾病中發現. protein堆積表徵是 unded, eosinophilic droplets, vacuoles, or aggregates in the cytoplasm 有幾種情況可以看到這樣的現象 1.腎臟近曲小管發生滲漏protein. 導致protein堆積 2.細胞合成過量的分泌性蛋白質,例如為了製造免疫球蛋白 3.Defects in protein folding HYALINE CHANGE The term hyaline usually refers to an alteration within cells or in the extracellular space, which gives a homogeneous, glassy, pink appearance in routine histologic sections stained with hematoxylin and eosin. 在細胞外在HE染色下會出現玻璃狀. 當一些膠源蛋白所引起的fibrosis會出現這樣的變化 GLYCOGEN 在醣類代謝異常時會出現glycogen的堆積.periodic acid schiff (PAS)的染色可以染出 PIGMENTS Exogenous Pigments 常見的就是一些空氣污染的碳和煤渣所引起.macrophage會去吞這些髒東西 Endogenous Pigments 1. Lipofuscin is composed of polymers of lipids and phospholipids complexed with protein. lipofusin 可能是由lipid過氧化,或是未飽和lipid的 membrane所衍生而來. 呈現棕色. 2.Melanin; 成因: non-hemoglobin-derived, brown-black pigment formed when the enzyme tyrosinase catalyzes the oxidation of tyrosine to dihydroxyphenylalanine in melanocytes 3.Hemosiderin; 成因: 鐵的一些沈積所造成. hemoglobin-derived, golden yellow-to-brown, granular or crystalline pigment in which form iron is stored in cells. 以下的一些狀況, 會造成鐵在組織器官的堆積, 稱為 hemosiderosis (1) increased absorption of dietary iron, (2) impaired use of iron, (3) hemolytic anemias, and (4) transfusions because the transfused red cells constitute an exogenous load of iron. 可以看切片圖,對於形態上的描述 Iron pigment appears as a coarse, golden, granular pigment lying within the cell's cytoplasm ------------------ Pathologic Calcification 鈣化對於鈣化, 書上就先定義一下 Pathologic calcification is the abnormal tissue deposition of calcium salts, together with smaller amounts of iron, magnesium, and other mineral salts. It is a common process occurring in a variety of pathologic conditions. 書中介紹兩種鈣化的原因 DYSTROPHIC CALCIFICATION 只存在於necrosis細胞附近的鈣化形態上: the calcium salts have a basophilic, amorphous granular, sometimes clumped, appearance. 一但發生, 單一necrosis便會成回結晶的來源, 然後層層延伸. 形成psammoma bodies. Pathogenesis成因: 兩個phase: 1) initiation (or nucleation) 胞內mit因為細胞死後,開始堆積鈣質 2) propagation 有下面幾步驟 (1) calcium ion binds to the phospholipids present in the vesicle membrane, (2) phosphatases associated with the membrane generate phosphate groups, which bind to the calcium, (3) the cycle of calcium and phosphate binding is repeated, raising the local concentrations and producing a deposit near the membrane, and (4) a structural change occurs in the arrangement of calcium and phosphate groups, generating a microcrystal, which can then propagate and perforate the membrane. METASTATIC CALCIFICATION 蔓延到正常組織的鈣化當發生 hypercalcemia 時候會有這樣的鈣化情況發生. 造成hypercalcemia原因, 書上提了四點 (1) increased secretion of parathyroid hormone (PTH) with subsequent bone resorption, as in hyperparathyroidism due to parathyroid tumors, and ectopic secretion of PTH-related protein by malignant tumors (Chapter 7); (2) destruction of bone tissue, occurring with primary tumors of bone marrow (e.g., multiple myeloma, leukemia) or diffuse skeletal metastasis (e.g., breast cancer), accelerated bone turnover (e.g., Paget disease), or immobilization; (3) vitamin D-related disorders, including vitamin D intoxication, sarcoidosis (in which macrophages activate a vitamin D precursor), and idiopathic hypercalcemia of infancy (Williams syndrome), characterized by abnormal sensitivity to vitamin D; and (4) renal failure, which causes retention of phosphate, leading to secondary hyperparathyroidism. 這在身體的各組織中都可以見到. ---------------------------------- 終於到了這章的末節要談得是細胞老化當細胞老化會有生理和結構上的改變, 並且減緩proliferation. 接下來分成幾個部份來談 Structural and Biochemical Changes with Cellular Aging. 老化細胞減弱了吸收營養的能力, 導致於削弱修復DNA功能. 而胞內也出現了許多變化不正常的lobed nuclei, pleomorphic vacuolated mitochondria, decreased endoplasmic reticulum, and distorted Golgi apparatus. 然後沈積一些色素 Replicative Senescence. 這個主要建立在一個細胞具有有限的DNA複製能力, 然後提到telomer變短然後慢慢造成cell cycle休止 Genes That Influence the Aging Process. 有些基因會跟老化有關係, 例如Foxo family Accumulation of Metabolic and Genetic Damage. 最後談到當細胞/DNA累積許多傷害到一定的程度,會開始讓細胞出現老化現象. 第一章導讀大概就是這樣 ^^ ※ 編輯: HIbaby 來自: 133.11.70.112 (06/12 15:25)