Skin Flaps

To improve the reader's understanding of flap classification, the author has summarized the most commonly used classifications into 3 simplified categories: type of blood supply, type of tissue to be transferred, and location of donor site.
Blood supply:
The classification of flaps based on blood supply, including the Mathes and Nahai subclassification, can be summarized as follows:

• Random (no named blood vessel)
• Axial (named blood vessel) Mathes and Nahai classification
  • One vascular pedicle (eg, tensor fascia lata)
  • Dominant pedicle(s) and minor pedicle(s) (eg, gracilis)
  • Two dominant pedicles (eg, gluteus maximus)
  • Segmental vascular pedicles (eg, sartorius)
  • One dominant pedicle and secondary segmental pedicles (eg, latissimus dorsi)

A Severe Headache in a Young Woman

An ambulance brings a 39-year-old woman complaining of a severe occipital headache and vomiting from her workplace to the emergency department (ED).

Graft classification

Skin grafts can be

• Split-thickness - epidermis and variable amounts of dermis. Commonly taken from the thigh or buttocks. The donor site heals by re-epitheliasation from the dermis and surrounding skin and requires dressings.
• Full - thickness- epidermis and all the dermis. The donor site is either sutured directly or split-thickness skin grafted.
• Composite graft - small grafts containing skin and underlying cartilage or other tissue. Donor sites include, for example, ear skin and cartilage to reconstruct nasal alar rim defects.

wound classification

Clean: An uninfected operative wound in which no inflammation is encountered and the respiratory, alimentary, genital, or uninfected urinary tract is not entered.

Clean-Contaminated: An operative wound in which the respiratory, alimentary, genital, or urinary tracts are entered under controlled conditions and without unusual contamination.

Contaminated: Open, fresh, accidental wounds

Type of Fracture

Dyspnea on Exertion in a 46-Year-Old Man

A 46-year-old man presents to the emergency department with a 5-day history of progressively worsening breathlessness on exertion and mild, general flulike symptoms. He also complains about night sweats and an intermittent low-grade fever, both of which started about 2 weeks ago.

http://cme.medscape.com/viewarticle/732708?src=emed_case_nl_0&uac=149212BX

Muscle Contraction Mechanism(Skeletal and Cardiac Muscle)

http://en.wikipedia.org/wiki/Muscle_contraction

Interleukin

Interleukins are a group of cytokines (secreted proteins/signaling molecules) that were first seen to be expressed by white blood cells (leukocytes).
The majority of interleukins are synthesized by helper CD4+ T lymphocytes, as well as through monocytes, macrophages, and endothelial cells. They promote the development and differentiation of T, B, and hematopoietic cells.

http://en.m.wikipedia.org/wiki/Interleukin?wasRedirected=true

Fever and Joint Pain in a 48-Year-Old Man

A 48-year-old man presents to the emergency department (ED) with a 10-day history of intermittent subjective fever and pain in his hands. He has also noticed 2 swollen and painful areas on his thumbs. Concurrently with the fever, he reports weakness, malaise, watery diarrhea, weight loss, anorexia, and intermittent vomiting.





http://cme.medscape.com/viewarticle/731210?src=emed_case_nl_0&uac=149212BX

A 34-Year-Old Woman With Headache, Dizziness, and Poor Coordination

http://cme.medscape.com/viewarticle/730607?src=emed_case_nl_0&uac=149212BX

Tonicity

Tonicity is a measure of the osmotic pressure (as defined by the water potential of the two solutions) of two solutions separated by a semipermeable membrane.

facilitated diffusion

facilitated diffusion The transport of molecules across the plasma membrane of a living cell by a process that involves a specific transmembrane carrier (see transport protein) located within the plasma membrane but does not require expenditure of energy by the cell.

Osmotic pressure

Osmotic pressure is the pressure applied by a solution to prevent the inward flow of water across a semipermeable membrane.[1]

diffusion

diffusion (passive transport) The random movement of particles (e.g. molecules or ions) from an area of high concentration to an area of low concentration until an even distribution of particles (i.e. uniform concentration) is obtained

osmosis

Osmosis:the movement of water across a selectively permeable membrane from an area of high water potential (low solute concentration) to an area of low water potential (high solute concentration).

euthyroid

 Figure 3. Sonograms showing longitudinal (left panel) and transverse (right panel) images of the left lobe containing a degenerated thyroid nodule. Note the thick wall and irregularity. N=nodule, H=hemorrhagic degenerated region.

 Figure 4. The left panel shows an anterior scintiscan of a euthyroid patient who had a tense nodule in the left thyroid lobe. The nodule is "cold". * * * =nodule. The right panel shows a sonogram of the neck in the longitudinal plane revealing that the nodule is a smooth-walled cystic structure without internal echoes. between the + + symbols. Note the dark dense echoes distal to the cyst. C=cyst, L=thyroid lobe.

Figure 5. Sonogram of the neck in the longitudinal plane showing a hypoechogenic nodule that was surrounded by an echo free rim, called a halo. Doppler examination demonstrated great vascularity in the halo, identified as bright spots. Small blood vessels are also seen elsewhere. N=nodule, L=heterogenous thyroid lobe, m=muscle.

Thyroid hormone synthesis

Figure 3

  Schematic diagram of a follicular cell, illustrating the steps involved in thyroid hormone synthesis. TSH receptor (TSHR) bound to TSH stimulates iodide transport into the thyroid gland by the sodium iodide symporter (NIS). Subsequently, iodide is oxidised by hydrogen peroxide, generated by the recently discovered NADPH oxidase system (ThOX) and bound to tyrosine residues in thyroglobulin (TG) to form iodotyrosine (iodide organification). Some of these hormonally inactive iodotyrosine residues (monoiodotyrosine and diiodotyrosine) couple to form the hormonally active iodothyronines, T₄ and T₃. Thyroid peroxidase (TPO) catalyses the oxidation, organification, and coupling reactions. The exact function of pendrin, a chloride-iodide transporter, in thyroid hormone synthesis is as yet unknown but it is thought to transport iodide into the colloid from the thyrocyte. Defects in any of these steps lead to dyshormonogenesis, which manifests clinically as congenital hypothyroidism with goitre.

epigastric pain

A 21-year-old white man presents to the emergency department with a 10-hour history of epigastric pain that is radiating to the chest.



http://cme.medscape.com/viewarticle/729522?src=emed_case_nl_0&uac=149212BX

A 19-year-old white woman presents to the clinic after a hospital visit for headaches.

A 19-year-old white woman presents to the clinic after a hospital visit for headaches. She has had headaches for approximately 5 years and they have been progressively increasing in frequency.



http://cme.medscape.com/viewarticle/730007?src=emed_case_nl_0&uac=149212BX

Mauriceau–Smellie–Viet maneuver

Lovset's Maneuver

Open book fracture

• Most serious fracture
• destroys at least two elements
• high risk of arterial bleeding
• unstable 
• needs surgical repair

Sacral Fracture

• High Impact anterior or posterior truama
• fracture at or lateral to sacroiliac joints
• usually part of complex pelvic fracture
• causes open book  fracture when at least one other element is fracture
• unstable fracture

Dashboard Fracture

• Fracture of Posterior Ramus of Acetabulum by Femoral Head
• Associate severe knee injure

Ishcial Tuberosity Avulsion

• Ischial tuberosity Avulsion
• Effect Function of Sartorius, Rectus Femmorus or Hamstring Muscles
• Horizontal Trauma
• Usually Heals with Deformity

Straddle Fracture

• Fracture of bilateral inferior pubic rami
• Direct Horizontal
• Frequently Injures the Urethra

Aortic Disruption

• Wide mediasternum
• Apical Cap
• Lt Mainstem Bronchus Depress
• Rt Mainstem Bronchus Elevate
• Deviation of trachea
• Obliteration of Aortic knob(disappear of aortic arch)
• Absence of Aorticopulmonary window
• Widened Paratracheal stripe
• Left Hemothorax

X-Ray

Structures seen on a posteroanterior (PA) chest x-ray. 1 = first rib; 2–10 = posterior aspect of ribs 2–10; AK = aortic knob; APW = aortopulmonary window, BS = breast shadow (labeled only on right); C = carina; CA = colonic air; CPA = costophrenic angle, DA = descending aorta; GA = gastric air; LHB = left heart border (Note: Most of the left heart border represents the left ventricle; the superior aspect of the left heart border represents the left atrial appendage.); LPA = left pulmonary artery; RC = right clavicle (left clavicle not labeled); RHB = right heart border (Note: The right heart border represents the right atrium.); RHD = right hemidiaphragm (left hemidiaphragm not labeled); RPA = right pulmonary artery; T = tracheal air column.




Structures seen on a lateral chest x-ray. A = aorta; CPA = posterior costophrenic angle; LHD = left hemidiaphragm; PHB = posterior heart border (Note: The posterior heart border represents the left atrium superiorly and left ventricle inferiorly; the anterior heart border is not clearly defined on this film but represents the right ventricle.); RA = retrosternal airspace; RHD = right hemidiaphragm; RMF = right major fissure (left major fissure and minor fissures not well visualized on these films but can occasionally be seen); S = scapula; T = tracheal air column.

Pneumothorax

British professional guidelines have traditionally stated that the measurement should be performed at the level of the hilum (where blood vessels and airways enter the lung),^[4] while American guidelines state that the measurement should happen at the apex (tip) of the lung.^[9] The latter method may overestimate the size of a pneumothorax if it is located mainly at the apex, which is a common occurrence.^[4] The various methods correlate poorly, but are the best immediately available ways of estimating pneumothorax size.

Dens Fracture

 Radiologic evaluation is utilized to confirm the diagnosis and estimate the degree of spinal instability. Initial evaluation includes open-mouth, anterior-posterior, and flexion-extension lateral radiographs. Os odontoideum appears as a round or oval ossicle with a smooth, uniform cortex separated from the base of the axis by a wide gap. The ossicle border does not directly match up with the axis body. The gap separating the os and the axis proper should lie above the level of the superior articular facets. Orthotopic os odontoideum (see image below) may appear free and in a relatively anatomic position.^30,31,32

Clay Shoveler's Fracture

• oblique fracture
• Lower cervical spine process, usually C7
• caused by Hyperflexion (bending work)

Hangman's Fracture

- Bilateral posterior Pedicle Fracture of C2
-Associated with anterior dislocation of c2 vertebral body
-Caused by severe extension injury (face hitting windshield)

extension Tear Drop Fracture

• Fracture of the cervical spine caused by the sudden pull of the anterior longitudinal ligament on the anterior, inferior aspect of the vertebral body following extreme hyperextension of the neck
• Usually involves C2
  • Anterior longitudinal ligament inserts on anteroinferior aspect of C2
• Fracture of C2 is stable in flexion and unstable in hyperextension

Apical Cap in aortic injury

 The lateral margins of the lateral masses (inferior
articular facets of C1) should align with the lateral
margins of the structures below it (superior articular
facets of C2).  The space between these two facets is
the atlanto-axial joint.  In  this radiograph, the lateral
masses of C1 are displaced outward, indicating a
"bursting" of the ring of C1 (the Jefferson Fracture).

jefferson fracture

 The lateral margins of the lateral masses (inferior
articular facets of C1) should align with the lateral
margins of the structures below it (superior articular
facets of C2).  The space between these two facets is
the atlanto-axial joint.  In  this radiograph, the lateral
masses of C1 are displaced outward, indicating a
"bursting" of the ring of C1 (the Jefferson Fracture).

Different Between spinal and neurogenic shock?

neurogenic shock occure after spinal cord injury but spinal shock occure long time month or year after spinal cord injury

Subarachnoid Hemorrhage

Figure 3: Non-contrast CT scan of the brain demonstrating subarachnoid hemorrhage (SAH) in a patient with the sudden onset of a severe headache and stiff neck 1 hour prior to this scan.

Cerebral Contusion:

This is a scan of a patient who has sustained a severe head injury. There is extensive bruising of the right side of the brain, showing up as a large, diffuse grey area. You can also see that there are patches of white within the grey area. This represents bleeding. The grey area represents swelling (oedema). The area of the cortical contusion is outlined in purple. You will normally find a centimetre scale at the right hand side of a CT scan. This scan would be classified on the Early Outcome Form as "Cortical contusion - greater than 1cm in diameter.

Diffuse Axonal Injury:

One or more petechial haemorrhages within the brain
The presence of petechial haemorrhages is usually an indication of a very severe primary brain injury. Petechial haemorrhages tend to occur at the interface of grey and white matter. It can also occur in the dorsolateral quadrant of the midbrain at the middle orange arrow, as well as elsewhere within the brain substance. Note on this scan, that the lateral ventricles and the third ventricle are visible and there is no midline shift. It is often a characteristic of diffuse axonal injury, in which there are numerous petechial haemorrhages that there is no evidence of brain swelling, or midline shift. This scan would be classified as showing one, or more, petechial haemorrhages within the brain.

Acute Extradural Haematoma:

Intracranial haematoma - non-evacuated
This scan shows another intracranial haematoma, namely an extradural. You will note that this haematoma has a concave shape, a bit like the human lens and this is because it is occurring between the bone and the dura and is not actually lying on the surface of the brain itself. The points of attachment of the dura limit the extension of this haematoma anteriorly and posteriorly. You can see that there is shift of the midline. Look at the frontal horns in their relation to the falx cerebri (falx cerebri is outlined on the normal scan). This scan would be classified "Intracranial haematoma - non evacuated."

Acute Subdural Haematoma Demonstrating Midline Shift:

Midline shift >5mm
Intracranial haematoma - non evacuated
Cortical contusion >1cm in diameter
Obliteration of 3rd Ventricle (not seen - refer to normal CT scan)

This CT scan shows a right sided acute haematoma, as well as an associated cerebral contusion (bruising). The true midline has been outlined by yellow dots and you can see that the frontal horns of the lateral ventricles have been pushed over to the left. In addition, the third ventricle is now not visible and it is also extremely difficult to make out the basal cisterns. This scan demonstrates four of the features which are included on the Early Outcome Form, namely midline shift greater than 5mm, intracranial haematoma - non evacuated, cortical contusion greater than 1cm in diameter and obliteration of the third ventricle. This haematoma requires surgical evacuation, otherwise deterioration of the patient's condition is inevitable. 

Normal CT Scan:

It is worth spending a few minutes familiarising yourself with the appearances of a normal CT scan. It is much easier to detect abnormalities once you are accustomed to normal appearances. The scan below is a slice through the human brain and you should imagine that you are viewing it as if looking up from the patient's feet. Therefore, the patient's left is to the right of the screen. The shape of the ventricles is quite distinctive and they are shown outlined in green and orange. The presence of the third ventricle in the midline is one of the first things to look for. If the third ventricle is either not visible, or shows signs of shift away from the midline, this suggests that there is an abnormality. The basal cisterns is the fluid filled space around the back of the midbrain outlined here in purple. Blood clots, or swelling of the brain may cause this to become narrowed, or not visible altogether. Note in this scan, that the frontal horns of the lateral ventricles are symmetrical, with the septum between them in the midline.

Determination of the effector T cell response

T_h1/T_h2 Model for helper T cells. An antigen is ingested and processed by an APC. It presents fragments from it to T cells. The upper, T_h0, is a T helper cell. The fragment is presented to it by MHC2.^[1] IFN-γ, interferon γ; TGF-β, transforming growth factor β; mø, macrophage; IL-2, interleukin 2; IL-4, interleukin 4

	Type 1/ Th1	Type 2/ Th2
Main partner cell type	Macrophage	B-cell
Cytokines produced	interferon-γ and tumor necrosis factor-beta. (Interleukin-2 was classically associated with Th1 cells, but this association may be misleading; IL-2 is produced by all helper T cells early in their activation.)	interleukin-4, interleukin-5, interleukin-6, interleukin-10, interleukin-13
Immune stimulation promoted	Cellular immune system. Maximizes the killing efficacy of the macrophages and the proliferation of cytotoxic CD8+ T cells. Also produces opsonizing antibodies	Humoral immune system. Stimulates B-cells into proliferation, to induce B-cell antibody class switching, and to increase neutralizing antibody production.
Other functions	The Type 1 cytokine IFN-γ increases the production of interleukin-12 by dendritic cells and macrophages, and via positive feedback, IL-12 stimulates the production of IFN-γ in helper T cells, thereby promoting the Th1 profile. IFN-gamma also inhibits the production of cytokines such as interleukin-4, an important cytokine associated with the Type 2 response, and thus it also acts to preserve its own response.	The Type 2 response promotes its own profile using two different cytokines. Interleukin-4 acts on helper T cells to promote the production of Th2 cytokines (including itself; it is auto-regulatory), while interleukin-10 (IL-10) inhibits a variety of cytokines including interleukin-2 and IFN-γ in helper T cells and IL-12 in dendritic cells and macrophages. The combined action of these two cytokines suggests that once the T cell has decided to produce these cytokines, that decision is preserved (and also encourages other T cells to do the same).

CD4

CD4 (cluster of differentiation 4) is a glycoprotein expressed on the surface of T helper cells, regulatory T cells, monocytes, macrophages, and dendritic cells.
Note:Regulatory T cells (T_reg, sometimes known as suppressor T cells)
Function
CD4 is a co-receptor that assists the T cell receptor (TCR) to activate its T cell following an interaction with an antigen-presenting cell. Using its portion that resides inside the T cell, CD4 amplifies the signal generated by the TCR by recruiting an enzyme, known as the tyrosine kinase lck, which is essential for activating many molecules involved in the signaling cascade of an activated T cell. CD4 also interacts directly with MHC class II molecules on the surface of the antigen-presenting cell using its extracellular domain

Medical Robotics Bioports to the Human Body

http://www.youtube.com/watch?v=7RKnr6XXPps&feature=channel

IMRI & Positron Emission Tomography: A New Tool for Biomedical Imaging?

http://www.youtube.com/watch?v=jdBvPkJv1YM&feature=related

Phosphodiesterase

PDE substrate specificities by enzyme family. Both means it hydrolyzes both cAMP and cGMP.

Classification and nomenclature

The PDE superfamily of enzymes is classified into 11 families, namely PDE1-PDE11, in mammals. The classification is based on:

• amino acid sequences
• substrate specificities
• regulatory properties
• pharmacological properties
• tissue distribution.

Clinical significance
phosphodiesterase enzymes are often targets for pharmacological inhibition due to their unique tissue distribution, structural properties, and functional properties. ^[8]
Inhibitors of PDE can prolong or enhance the effects of physiological processes mediated by cAMP or cGMP by inhibition of their degradation by PDE

http://en.wikipedia.org/wiki/Phosphodiesterase#Clinical_significance

PCR

The polymerase chain reaction (PCR) is a scientific technique in molecular biology to amplify a single or few copies of a piece of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence
Developed in 1983 by Kary Mullis,^[1] PCR is now a common and often indispensable technique used in medical and biological research labs for a variety of applications.^[2][3] These include DNA cloning for sequencing, DNA-based phylogeny, or functional analysis of genes; the diagnosis of hereditary diseases; the identification of genetic fingerprints (used in forensic sciences and paternity testing); and the detection and diagnosis of infectious diseases. In 1993, Mullis was awarded the Nobel Prize in Chemistry for his work on PCR.^[

Prostagladin

what is the relationship between NSAIDs and Prostagladin (eicosanoids) ?

http://en.wikipedia.org/wiki/Eicosanoid
NSAID is a drug that block COX1 enzyme that convert Arachidonic Acid to Prostaglandin.
Prostaglandin Function:
- PGD2:Promotion of sleep
-PGE2: +Smooth muscle contraction;
             +inducing pain, heat, fever;
             +bronchoconstriction
-PGF2α:Uterine contraction
-PGI2: +Inhibition of platelet aggregation;
           + vasodilation; embryo implantation
http://en.wikipedia.org/wiki/Eicosanoid#Function_and_pharmacology

Ecosanoid

Ecosanoid

Eicosanoids


Origin and metabolism. The eicosanoids,

prostaglandins, thromboxane,

prostacyclin, and leukotrienes, are

formed in the organism from arachidonic

acid, a C20 fatty acid with four

double bonds (eicosatetraenoic acid).

Arachidonic acid is a regular constituent

of cell membrane phospholipids; it is

released by phospholipase A2 and forms

the substrate of cyclooxygenases and

lipoxygenases.

Synthesis of prostaglandins (PG),

prostacyclin, and thromboxane proceeds

via intermediary cyclic endoperoxides.

In the case of PG, a cyclopentane

ring forms in the acyl chain. The letters

following PG (D, E, F, G, H, or I) indicate

differences in substitution with hydroxyl

or keto groups; the number subscripts

refer to the number of double

bonds, and the Greek letter designates

the position of the hydroxyl group at C9

(the substance shown is PGF2!). PG are

primarily inactivated by the enzyme 15-

hydroxyprostaglandindehydrogenase.

Inactivation in plasma is very rapid;

during one passage through the lung,

90% of PG circulating in plasma are degraded.

PG are local mediators that attain

biologically effective concentrations

only at their site of formation.

Biological effects. The individual

PG (PGE, PGF, PGI = prostacyclin) possess

different biological effects.

Nociceptors. PG increase sensitivity

of sensory nerve fibers towards ordinary

pain stimuli (p. 194), i.e., at a given

stimulus strength there is an increased

rate of evoked action potentials.

Thermoregulation. PG raise the set

point of hypothalamic (preoptic) thermoregulatory

neurons; body temperature

increases (fever).

Vascular smooth muscle. PGE2

and PGI2 produce arteriolar vasodilation;

PGF2!, venoconstriction.

Gastric secretion. PG promote the

production of gastric mucus and reduce

the formation of gastric acid (p. 160).

Menstruation. PGF2! is believed to

be responsible for the ischemic necrosis

G-Protein Pathway

Receptor-Mediated Endocytosis

Schematic representation of the endocytic pathway and membrane trafficking. Ligands, such as hormones and growth factors, bind to specific surface receptors and are internalized in pinocytotic vesicles coated with clathrin and other proteins. After the liberation of the coating molecules, the pinocytotic vesicles fuse with the endosomal compartment, where the low pH causes the separation of the ligands from their receptors. Membrane with receptors is returned to the cell surface to be reused. The ligands typically are transferred to lysosomes. The cytoskeleton with motor proteins is responsible for all vesicle movements described.

Receptor-Mediated Endocytosis

Internalization of low-density lipoproteins (LDL) is important to keep the concentration of LDL in body fluids low. LDL, which is rich in cholesterol, binds with high affinity to its receptors in the cell membranes. This binding activates the formation of pinocytotic vesicles from coated pits. The vesicles soon lose their coating, which is returned to the inner surface of the plasmalemma: the uncoated vesicles fuse with endosomes. In the next step, the LDL is transferred to lysosomes for digestion and separation of their components to be utilized by the cell.

A 76-year-old man presents to the emergency department (ED) complaining of a sudden onset of abdominal pain.

A 76-year-old man presents to the emergency department (ED) complaining of a sudden onset of abdominal pain. The pain started about 4 hours before presentation to the ED and has been persistent; it is present in the upper abdomen and is centered in the epigastrium. He describes the pain as deep and burning. There is no associated nausea or vomiting. He does not report any changes in his bowel habits and has not experienced any recent fevers. The review of systems is also negative for any recent unintended weight loss or trauma. The patient also reports having had "indigestion" in the past that caused pain similar to what he is currently experiencing, though much less in intensity. His past medical history is significant for coronary artery disease and hypertension. He takes two medications, both for his high blood pressure, but does not drink excessively and does not smoke.
http://cme.medscape.com/viewarticle/727247?src=emed_case_nl_0&uac=149212BX

X-Ray of pneumopertoneum

Numerous signs are described for diagnosing pneumoperitoneum on plain radiographs. One of the best known, the Rigler sign (also known as the double-wall or bas-relief sign), is a visualization of the outer surface of a bowel loop wall resulting from free air in the peritoneal cavity. The intraluminal gas provides negative contrast and outlines the internal wall. The cupola sign, typically seen on supine radiographs, is an inverted cup-shaped arcuate lucency overlying the lower thoracic spine and projecting caudally to the heart. This sign is formed as air accumulates anteriorly in the median subphrenic space under the central leaf of the diaphragm. The umbilical ligaments, the urachus, and particularly the falciform ligament are sometimes identified as linear radiopaque structures in the presence of free air.[1,3,5,7]

cAMP dependent pathway Mechanism

http://en.m.wikipedia.org/wiki/Redox

Pancreatic artery