9. Absorption Across Membranes
Polar head:
choline, serine,
ethanolamine,
inositol
phosphate
Glycerol
backbone
2 nonpolar
fatty acids
•The membrane is a phospholipid bi-layer
consisting of a polar head group, phosphate,
glycerol backbone and 2 fatty acid molecules
esterified to the glycerol backbone.
• hydrophobic compounds can diffuse across
the membrane
• hydrophilic compounds will not diffuse
across the membrane
11. Types of Transport
1. Passive Diffusion—no ATP required;
gradient driven
a. Simple Diffusion—hydrophobic molecules
passively diffuse across the membrane.
Rate of transport proportional to the
octanol/water partition coefficient or logP.
b. Facilitated Diffusion—saturable carrier-mediated
transport (e.g. glucose transporter
2. Active Transport—
a) chemicals are moved against an
electrochemical gradient;
b) b) the transport system is saturable;
c) c) requires the expenditure of energy.
17. Mechanisms of PbToxicity
• Lead exerts numerous adverse mechanisms of toxicity.
Lead has a high affinity for sulfhydryl groups. It is
therefore particularly toxic to multiple enzyme systems.
• Many of lead’s toxic effects also result from its inhibition
of cellular function requiring calcium.
• Lead binds to calcium-activated proteins with much
higher (105 times) affinity than calcium.ё
18. • The interaction of lead and calcium with cellular sites
depends on the concentration of free ions present (ie,
Pb2+ and Ca2+).
• Pb2+ and Ca2+ compete at the plasma membrane for
transport systems, which affect their entry or exit (ie,
Ca2+ channels and the Ca2+ pump.)
19. • Intracellular Ca2+ is buffered by proteins, endoplasmic
reticulum, and mitochondria; Pb2+ disturbs this
intracellular Ca2+ homeostasis. A (Ca2+)-(Pb2+) interaction
at the mitochondria has been described.
• Pb2+ interacts with a number of Ca2+ -dependent effector
mechanisms, such as calmodulin (a Ca2+ receptor
protein, which couples to several enzymes, eg,
phosphodiesterase, protein kinases), protein kinase C,
Ca2+ -dependent K+channels in the plasma membrane
and neurotransmitter release
27. Хорлогын үеийн ABC
Basic axiom of care is symptomatic and
supportive treatment
address underlying problem only once
patient is stable
• A Airway (consider stabilizing the C-spine)
• B Breathing
• C Circulation
• D1 Drugs
• ƒ.ACLS as necessary to resuscitate the patient
• ƒ.universal antidotes
28. Хорлогын үеийн ABC
• D2 Draw bloods
• D3 Decontamination (decrease absorption)
• E Expose (хордлогын өвөрмөц шинжийг
ажигла)/өвчтөнийг сайн шинжил
• F Full vitals, ECG monitor, Foley, x-rays, etc.
• G Give specific antidotes, treatments
• Ахин үнэл
• Хордлогын төврүү мэдэгдэх
• Гэр бүлийнхэн болон хөндлөнгийн харсан хүнээс
нотолгоотой асуумж авах
29. D1 – Universal Antidotes
Treatments that will not harm patients and may be essential
Oxygen
• • do not deprive a hypoxic patient of oxygen no matter what the
antecedent medical history
• (i.e. even COPD with CO2 retention)
• • if depression of hypoxic drive, intubate and ventilate
• • exception: paraquat or diquat (herbicides) inhalation or ingestion
(oxygen radicals increase
• morbidity)
Glucose
• • give to any patient presenting with altered LOC
• • measure blood glucose prior to glucose administration if possible
• • adults: 0.5-1.0 g/kg (1-2 mL/kg) IV of D50W
• • children: 0.25 g/kg (2-4 mL/kg) IV of D25W
30. Thiamine (Vitamin B1)
• • 100 mg IV/IM to all patients with IV/PO glucose
• • a necessary cofactor for glucose metabolism, but do not
delay glucose if thiamine unavailable
• • to prevent Wernicke-Korsakoff syndrome
• • must assume all undifferentiated comatose patients are at
risk
Naloxone (central μ-receptor competitive antagonist,
shorter t1/2 than naltrexone)
• • antidote for opioids: administration is both diagnostic and
therapeutic (1 min onset of action)
• • used for the undifferentiated comatose patient
31. D2 – Draw Bloods
essential tests (see Table 24)
• ƒCBC, electrolytes, BUN/creatinine, glucose, INR/PTT,
osmolality
• ƒ.ABGs, measure O2 sat
• ƒ. acetylsalicylic acid (ASA), acetaminophen, EtOH levels
potentially useful tests
• ƒ.drug levels – this is NOT a serum drug screen
• Ca, Mg, PO4
• ƒ.protein, albumin, lactate, ketones, liver enzymes, CK –
depending on drug and clinical presentation