intro to bmeg final review

what is the moral norm “beneficence”?

provision of benefits

what is the moral norm “nonmaleficence”?

avoidance of doing harm

what is a therapeutic experiment?

one which has direct benefit to the patient, ex: clinical trial of new chemotherapy drug

what is a nontherapeutic experiment?

provide additional knowledge without direct benefit to the patient, ex: study of the impact of hepatitis infection

what is the group assigned for human research?

IRB (institutional review board)

what is the procedure for human study research?

1. investigator: initiates human research study protocol

2. protocol submitted to IRB for approval

3. revisions returned to investigator

4. revised version resubmitted to IRB for approval

what is needed for an IRB review?

number of subjects (statistically appropriate), safety assurances, privacy protection, informed consent documents

what is the most important aspect governing the ethics of human research and what are the requirements?

informed consent: always obtained in writing, voluntary, competent, allowed to enroll/disenroll at any time, randomization or controls vs not, subject has to be informed of all details, not a minor

what committee regulates animal research?

IACUC: institutional animal care and use committee

what are the 3Rs of animal research and what do they mean?

replace: priority should be to not use animals at all or replace animal usage in as many steps of the research process as possible, reduce: if animal use is inevitable, use the smallest amount of animals possible in order to still gain reliable results, refine: preventing or minimizing any pain to the animal if replace and reduce have already been exhausted

what is the FDA?

food and drug administration

what is the bauer study?

statistical test that gives the correct amount of animals/people for significant data

what are the four routes for registering a new device in the US?

product development protocol, 510(k) notification, IDE, and PMA

what are the 3 device classifications?

class 1: no significant risk, class 2: moderate risk, class 3: significant risk

examples and requirements of class 1

elastic bandages, crutches, most exempt from FDA registration

examples and requirements of class 2

venipuncture materials, blood pressure cuffs, most require 510(k)

examples and requirements of class 3

pacemakers, stents, breast implants, require PMA

what is 510(k) notification?

clearance for class 1 and class 2, mainly class 2, must prove “substantial equivalence” to another device that is currently on the market and approved (therefore safe). If not substantially equivalent, goes to class 3

what is PMA?

pre-market approval, review necessary to evaluate safety and effectiveness of device, requires evidence that the possible benefits to health outweigh the possible risks and that the device will significantly help a large portion of the target population. Like a license that can not be sold to another company if they want to market the same product.

what is IDE?

investigational device exemption, required for US human study of a significant risk device, pre-clinical to clinical, include documents to show FDA safety and efficacy

what are the four stages of clinical studies?

phase 1: safety and immunogenicity studies (10s)

phase 2: dose-ranging studies (100s)

phase 3: effectiveness and additional safety data (1000s)

phase 4: after PMA, continued oversight during sales

what is HDE?

humanitarian device exemption, new regulatory pathway established in 1990 for class 3 devices intended for rare diseases and conditions. Device must receive recognition as a humanitarian use device

what is a de novo request?

for new types of devices that have not been previously classified, if would have been class 3 could be class 1 or 2 if approved. can’t use route to lower class 3 device classification

what application needs to be approved to go from pre-clinical to clinical with drugs?

IND: investigational new drug

what do you need for FDA approval in drugs?

NDA: new drug application

what is autograft? what are advantages and disadvantages?

take cells from own body (patient). adv: no immune rejection. disadv: impractical for certain types of tissues

what is allograft? what are advantages and disadvantages?

take cells from other human. adv: human source. disadv: scarce of source, immune incompatibility.

what is xenograft? what are advantages and disadvantages?

take cells from animal source. adv: readily available. disadv: immune incompatibility, different functions

what is tissue engineering?

a biomedical engineering discipline integrating biology with engineering to create tissues of cellular products outside the body or to use the gained knowledge to better manage the repair of tissues within the body

what is regenerative medicine?

uses body’s natural regeneration mechanisms to repair damaged tissues

what is facultative regeneration?

will only regenerate under trauma or disease

what are the major steps in tissue engineering?

1. extraction of cells

2. cell culturing

3. seeding onto scaffolds

4. implantation

5. degradation

6. extracellular matrix

7. new healthy tissue

what is scaffold guided tissue engineering?

use of a scaffold to provide a temporal 3D architecture for cells attachment, growth, and forming a new tissue

what are the two distinctive properties of stem cells?

self renewal: ability to make identical copies of themselves, and differentiation: ability to form other cell types

what are requirements for scaffolds?

biocompatible, biodegradable, and bioabsorbable

what are the different types of stem cells?

pluripotent stem cells: can form most types of cells in the body, besides extra embryonic tissue, multipotent/oligopotent stem cells: can form multiple cell types, induced pluripotent stem cells: pluripotent stem cells by somatic cell “reprogramming”, adult stem cells: multipotent stem cells found in the adult body that are responsible for homeostasis (“committed” stem cells)

what are primary cells?

directly from source, difficult to culture

what are immortalized cell lines?

transformed cells that are easier to culture, can become tumorigenic

examples of ECM

fibers: collagen and elastin, provide strength and flexibility, proteoglycans: protein polysaccharide complexes, providing a voluminous matrix, adhesive glycoproteins: “glue” cells and ECM

what are natural materials for ECM?

collagen, fibrin, hyaluronic acid

what are synthetic materials for ECM?

polylactic acid (PLA) and polyglycolic acid (PGA)

details of collagen/elastin porous scaffold

fabricated by crosslinking collagen and elastin and freeze-drying, for culture of smooth muscle cells to form blood vessels

details of pla/pga based scaffold for ear cartilage

fabricated by pressing pla fibers into ear shape, chondrocytes are seeded onto scaffold

what are the different types of cell signaling in tissues?

soluble, insoluble, and environmental

what are soluble signals?

dissolved growth factors, hormones, and small molecules, able to drive cell growth, cell differentiation, etc

what are insoluble signals?

signaling molecules that are presented through ECM or cell surfaces

what are environmental signals?

mechanical loading

what cell categories are there for different cell types?

1. by donor: autologous, allogeneic, xenogenic

2. by differentiated state: differentiated somatic cells (biopsy), stem cells

3. by immortality/source: primary, immortalized cell lines