~Teachingcenter的醫學筆記~

 Amino Acids (胺基酸)

Essential amino acids (必須胺基酸)
= Must be contained in diet because these amino acids cannot be synthesized.
--- Valine (Val) (BCAA)
--- Leucine (Leu) (BCAA)
--- Isoleucine (Ile) (BCAA)
* Branched-chain amino acid (支鏈胺基酸)
--- Lysine (Lys)
--- Methionine (Met)
--- Threonine (Thr)
--- Phenylalanine (Phe)
--- Tryptophan (Trp)

Conditionally essential amino acids (條件式必需胺基酸)
= Semi-essential amino acid (半必需胺基酸)
= Conditionally indispensable because low synthesis rates may exceed requirements under certain conditions, especially in infants.
--- Arginine (Arg): Essential depending on health status of individual and for infants because it cannot be synthesized quickly enough
--- Histidine (His): Previously considered essential for infants; now also considered essential for adults
--- Tyrosine (Tyr): Can be synthesized from phenylalanine
--- Cysteine (Cys): Can be synthesized from methionine
--- Glutamine (Gln): Major energy source for intestinal mucosa
--- Proline (Pro)

Nonessential amino acids (非必須胺基酸)
= Needs can be fully met by synthesis.
--- Alanine (Ala)
--- Asparagine (Asn)
--- Aspartate (Asp)
--- Glutamine (Glu)
--- Glycine (Gly)
--- Serine (Ser)
 

維他命和微量元素在外科中的角色

Vitamin A
= 功能
--- Cofactor in collagen synthesis and cross linking
--- Antioxidant
--- Immune stimulation
--- Macrophage extravasation
--- Mucosal integrity
--- Regulation of glycoprotein synthesis
= 缺乏
--- Dermatitis
--- Night blindness
--- Xerophthalmia (乾眼症)
--- Respiratory ailments (pneumonia, bronchopulmonary dysplasia)
--- Impaired gut epithelial integrity
= 與外科的關聯
--- Wound healing and epithelial regeneration
--- Deficiency can result in diminished activity of helper T cells
--- Impaired mucous secretion when deficiency
--- Retinol-binding protein sensitive to nutritional status of individuals

Vitamin D
= 功能
--- Promotes absorption of calcium and phosphorus (by intestine and kidney)
--- Bone growth and bone remodeling (by osteoblasts and osteoclasts)
--- Regulates the synthesis of several structural proteins, including type I collagen
= 缺乏
--- Bone demineralization
= 與外科的關聯
--- Deficiency and impairment, causing bone demineralization and osteopenia

Vitamin E
= 功能
--- Antioxidant properties promote cell membrane integrity
= 缺乏
--- Increased platelet aggregation
--- Decreased red blood cell survival
--- Hemolytic anemia
--- Neurologic abnormalities
--- Decreased serum creatinine level
--- Excessive creatinuria
= 與外科的關聯
--- Prolonged steatorrhea and neuronal degeneration

Vitamin K
= 功能
--- Essential for coagulation
--- Prerequisite for wound healing
= 缺乏
--- Bruising
--- Hemorrhage
= 與外科的關聯
--- Deficiency reported in long-term antibiotic therapy or TPN lacking fat emulsions or malabsorption

Vitamin B1 (Thiamin)
= 功能
--- Cofactor in collagen cross linking
---Facilitates entry of glucose into the TCA cycle
= 缺乏
--- Beriberi
--- Lactic acidosis
--- Anorexia
--- Fatigue
--- Peripheral neuropathy
--- Wernicke-Korsakoff syndrome
--- Cardiomegaly
= 與外科的關聯
--- Deficiency reported in depleted patients who receive sudden load of carbohydrates
--- Wound healing
--- Treated with 25~100 mg thiamine per day

Vitamin B5 (Pantothenic acid)
= 功能
--- Component of coenzymes involved in energy release from macronutrients and synthesis of heme and fat
= 缺乏
--- Fatigue
--- Sleep disturbances
--- Nausea and vomiting
--- Abdominal cramps
--- Diarrhea
--- Muscle cramps
--- Mental depression
--- Hypoglycemia
= 與外科的關聯
--- Deficiency leading to poor wound healing and skin graft take

Biotin
= 功能
--- Coenzyme in carboxylation reactions (Gluconeogenesis, fatty acid, propionate synthesis)
= 缺乏
--- Glossitis
--- Dermatitis
--- Pallor
--- Hair loss
= 與外科的關聯
--- Deficiency caused by long-term TPN
--- Deficiency caused by alcoholism
--- Deficiency caused by post-gastrectomy

Vitamin C
= 功能
--- Antioxidant
--- Protects against free radical damage
--- Collagen cross linking and hydroxylation of lysine and proline during collagen formation
--- Immune-mediated and antibacterial functions of white blood cells
--- DNA, RAN replication
--- Lymphocyte function
= 缺乏
--- Fatigue
--- Anorexia
--- Muscular pain
--- Scurvy (Anemia, hemorrhagic disorders, defective collagen in bone, cartilage, teeth, connective tissues, muscle degeneration, gingivitis, capillary weakness, impaired wound healing)
= 與外科的關聯
--- Crucial in wound healing
--- Facilitates tissue regeneration
--- Collagen formation in bone, teeth, and connective tissue

Calcium
= 功能
--- Remodeling and degradation of collagen rely on calcium-dependent collagenases
= 缺乏
--- Osteoporosis
= 與外科的關聯
--- Important in reducing osteopenia and function of collagenases
--- Deficiency leading to hypotension and cardiovascular collapse or dysrhythmias
--- Deficiency leading to unresponsiveness of fluids and pressors
--- Deficiency leading to PTH end-organ resistance

Copper
= 功能
--- Promotes cross linking of collagen and elastin synthesis
--- Scavenges free radicals
= 缺乏
--- Skeletal demineralization
--- Impaired glucose tolerance
--- Anemia
--- Neutropenia
--- Leucopenia
--- Changes in skin and hair pigmentation
--- Linked to fatal arrhythmias and poorer outcomes
= 與外科的關聯
--- Significant wound exudate
--- Losses of copper and zinc known to occur in pediatric burn patients

Iron
= 功能
--- Essential in heme-containing molecules for oxygen transport (Hemoglobin) and storage (Myoglobin)
--- Electron transport and redox reactions (Cytochromes)
= 缺乏
--- Anemia
--- Cheilosis
--- Glossitis
--- Hair loss
--- Brittle finger nails koilonychias
--- Pallor
--- Tissue hypoxia
--- Exertional dyspnea
--- Heart enlargement
= 與外科的關聯
--- Deficiency may occur because of anemia and blood loss
--- Inadequacy leading to reduced resistance to infection and cold intolerance

Magnesium
= 功能
--- Cofactor in protein and collagen synthesis
= 缺乏
--- Nausea
--- Muscle weakness
--- Irritability
--- Mental derangement
= 與外科的關聯
--- Deficiency can lead to cardiac arrhythmia
--- Deficiency can lead to increased nervous system irritability and tetany

Selenium
= 功能
--- Reduces intracellular hydroperoxides
--- Protects membrane lipids from oxidative damage
--- May reduce mortality in critically ill patients
= 缺乏
--- Growth retardation
--- Muscle pain and weakness
--- Myopathy
--- Cardiomyopathy
= 與外科的關聯
--- Important in cell-mediated immune function
--- Deficiency can lead to altered thyroid hormone metabolism
--- Increased plasma glutathione levels

Zinc
= 功能
--- Essential cofactor in a wide range of enzyme systems involved in protein synthesis
--- Metalloenzymes
--- DNA replication
--- Immune function
--- Collagen formation
--- Cross linking
= 缺乏
--- Hair loss
--- Dermatitis
--- Growth retardation
--- Delayed sexual maturation
--- Testicular atrophy
--- Decreased appetite
--- Depressed smell and taste acuity
--- Diarrhea
= 與外科的關聯
--- Deficiency can cause impaired wound healing
--- May affect bone formation
--- Wound exudate losses

Adapted from Norbury WB, Situ E, Herndon DN: Nutritional support in the critically ill. In Cameron JL (ed): Current surgical therapy, ed 9, Philadelphia, 2007, Mosby Elsevier, pp 1234-1245.