The complex circuitry interconnecting different areas in the brain, known collectively as white matter, is composed of millions of axons organized into fascicles and bundles. Upon macroscopic examination of sections of the brain, it is difficult to discern the orientation of the fibers. The same is true for conventional imaging modalities. However, recent advancements in magnetic resonance imaging (MRI) make such task possible in a live subject. By sensitizing an otherwise typical MRI sequence to the diffusion of water molecules it is possible to measure their diffusion coefficient in a given direction1. Normally, the axonal membrane and myelin sheaths pose barriers to the movement of water molecules and, thus, they diffuse preferentially along the axon2. Therefore, the direction of white matter bundles can be elucidated by determining the principal diffusivity of water. The three-dimensional representation of the diffusion coefficient can be given by a tensor and its mathematical decomposition provides the direction of the tracts3; this MRI technique is known as diffusion tensor imaging (DTI). By connecting the information acquired with DTI, three-dimensional depictions of white matter fascicles are obtained4. The virtual dissection of white matter bundles is rapidly becoming a valuable tool in clinical research.

Our journey begins with a transverse section of tightly packed axons as seen through light microscopy. Although represented as a two-dimensional "slice", we see that these axons in fact resemble tubes. A simulation of water molecules diffusing randomly inside the axons demonstrates how the membranes and myelin hinder their movement across them and shows the preferred diffusion direction --along the axons. The tracts depicted through DTI slowly blend in and we ride along with them. As we zoom out even more, we realize that it is a portion of the corpus callosum connecting the two sides of the brain we were traveling on and the great difference in relative scale of the individual axons becomes evident. The surface of the brain is then shown, as well as the rest of the white matter bundles--a big, apparently chaotic tangle of wires. Finally, the skin covers the brain.

With the exception of the simulated water molecules, all the data presented in the animation is obtained through microscopy and MRI. Computer algorithms for the extraction of the cerebral structures and a custom-built graphics engine make our journey through the brain's anatomy possible in a living person.

Micrograph courtesy of Dr. Christian Beaulieu, University of Alberta.
Music by Mario Mattioli.

References:
1. Stejskal, E.O., et al., J. Chem. Phys., 1965. 42:
2. Beaulieu, C., NMR Biomed., 2002. 15:435-55.
3. Basser, P.J., et al., J. Magn. Reson. B, 1994. 103:247-54.
4. Mori, S., et al., NMR Biomed., 2002. 15:468-80.

Sinus infections caused by viruses can use home (over-the-counter, OTC) treatments such as pain and fever medications (acetaminophen [Tylenol]), decongestants, and mucolytics. In addition, some health-care professionals suggest nasal irrigation or a sinus rinse solution to help relieve symptoms of sinus infections, even chronic sinusitis symptoms.

Millions of sperms are deposited into the vagina during sexual intercourse. The sperms make their way through the cervix into the uterus and then on to the fallopian tubes. As they swim along this way their numbers decline. Only a few hundred sperm will get close to the egg. During the trip, sperm prepare themselves to meet the egg by subtle alterations of their heads and movement patterns. Once inside the fallopian tube, the sperm attracts the egg by releasing a chemical. The egg is surrounded by a protective covering called the zona pellucida, which allows only one sperm to penetrate it. Once inside the egg, the head of the fertilizing sperm releases its genetic contents, which fuses with the nucleus of the egg. Fertilisation is now complete. Sperm are able to survive for 2-3 days within the female's reproductive tract. The length of the time that a woman's egg can be fertilized by a man's sperm ranges from 12-24 hours.

HD Hip Replacement Surgery

Laser Dental Surgery HD

Ergometrine Childbirth Medication

AZT Mechanism of Antiviral Activity

Is it possible to prevent cytomegalovirus infection? Is there a CMV vaccine? Cytomegalovirus (CMV) infection facts CMV is a common virus in the same family as herpesvirus, and it can infect anyone. CMV is spread by direct contact of body fluids, such as saliva, blood, urine, semen, vaginal fluids, and breast milk. Thus breastfeeding, blood transfusions, organ transplants, and sexual contact are possible modes of transmission. Most healthy people do not experience any symptoms when infected with CMV, and it does not pose a serious health concern. A majority of adults have antibodies consistent with past infection. Most healthy children and adults who do have symptoms will recover from CMV infection without complications and do not require antiviral treatment.

Anatomy of The Shoulder and Arm Muscles

Histology of Aorta

Niemann-Pick disease is a condition that affects many body systems. It has a wide range of symptoms that vary in severity. Niemann-Pick disease is divided into four main types: type A, type B, type C1, and type C2. These types are classified on the basis of genetic cause and the signs and symptoms of the condition. Infants with Niemann-Pick disease type A usually develop an enlarged liver and spleen (hepatosplenomegaly) by age 3 months and fail to gain weight and grow at the expected rate (failure to thrive). The affected children develop normally until around age 1 year when they experience a progressive loss of mental abilities and movement (psychomotor regression). Children with Niemann-Pick disease type A also develop widespread lung damage (interstitial lung disease) that can cause recurrent lung infections and eventually lead to respiratory failure. All affected children have an eye abnormality called a cherry-red spot, which can be identified with an eye examination. Children with Niemann-Pick disease type A generally do not survive past early childhood.

Histology of Esophagus

Histology of Secretory Endometrium

Stephen Slade shows a 1 week post op patient after DSAEK. DSAEK is an excellent option for many patients with corneal disease. In DSAEK, only the thin, inner layer is replaced, so the healing is typically much faster than a full thickness cornea graft.

Wash your hands thoroughly with soap and water before and after treating the wound. Wash the area with mild soap and running water to reduce the risk of infection. Pat dry. Apply antibiotic ointment and cover with a clean bandage or sterile dressing. Antibiotic prophylaxis should be considered, especially if there is a high risk of infection, such as with cat bites, with puncture wounds, with wounds to the hand, and in persons who are immunosuppressed. Amoxicillin/clavulanate is the first-line prophylactic antibiotic.

Hemophagocytic lymphohistiocytosis is a rare but life threatening condition characterised by activation of macrophages which result in phagocytosis of RBCs and cytokine mediated tissue damage. This presentation aims to discuss the genetic basis, clinical features, diagnostic criteria and management options in this serious condition. The management options in HLH include Etoposide, Dexamethasone, Cyclosorine, Tacrolimus, Alemtuzumab and stem cell transplant.

Root canals are common procedures and can help save your tooth from extraction. Dentists at Aspen Dental practices have been safely and expertly performing root canal procedures for over two decades.

Scoliosis is a sideways curvature of the spine that occurs most often during the growth spurt just before puberty. While scoliosis can be caused by conditions such as cerebral palsy and muscular dystrophy, the cause of most scoliosis is unknown. Most cases of scoliosis are mild, but some children develop spine deformities that continue to get more severe as they grow. Severe scoliosis can be disabling. An especially severe spinal curve can reduce the amount of space within the chest, making it difficult for the lungs to function properly. Children who have mild scoliosis are monitored closely, usually with X-rays, to see if the curve is getting worse. In many cases, no treatment is necessary. Some children will need to wear a brace to stop the curve from worsening. Others may need surgery to keep the scoliosis from worsening and to straighten severe cases of scoliosis.

Treatment for kidney stones varies, depending on the type of stone and the cause. Small stones with minimal symptoms Most kidney stones won't require invasive treatment. You may be able to pass a small stone by: Drinking water. Drinking as much as 2 to 3 quarts (1.9 to 2.8 liters) a day may help flush out your urinary system. Unless your doctor tells you otherwise, drink enough fluid — mostly water — to produce clear or nearly clear urine. Pain relievers. Passing a small stone can cause some discomfort. To relieve mild pain, your doctor may recommend pain relievers such as ibuprofen (Advil, Motrin IB, others), acetaminophen (Tylenol, others) or naproxen sodium (Aleve). Medical therapy. Your doctor may give you a medication to help pass your kidney stone. This type of medication, known as an alpha blocker, relaxes the muscles in your ureter, helping you pass the kidney stone more quickly and with less pain. Large stones and those that cause symptoms Kidney stones that can't be treated with conservative measures — either because they're too large to pass on their own or because they cause bleeding, kidney damage or ongoing urinary tract infections — may require more extensive treatment. Procedures may include: Using sound waves to break up stones. For certain kidney stones — depending on size and location — your doctor may recommend a procedure called extracorporeal shock wave lithotripsy (ESWL). ESWL uses sound waves to create strong vibrations (shock waves) that break the stones into tiny pieces that can be passed in your urine. The procedure lasts about 45 to 60 minutes and can cause moderate pain, so you may be under sedation or light anesthesia to make you comfortable. ESWL can cause blood in the urine, bruising on the back or abdomen, bleeding around the kidney and other adjacent organs, and discomfort as the stone fragments pass through the urinary tract. Surgery to remove very large stones in the kidney. A procedure called percutaneous nephrolithotomy (nef-row-lih-THOT-uh-me) involves surgically removing a kidney stone using small telescopes and instruments inserted through a small incision in your back. You will receive general anesthesia during the surgery and be in the hospital for one to two days while you recover. Your doctor may recommend this surgery if ESWL was unsuccessful. Using a scope to remove stones. To remove a smaller stone in your ureter or kidney, your doctor may pass a thin lighted tube (ureteroscope) equipped with a camera through your urethra and bladder to your ureter. Once the stone is located, special tools can snare the stone or break it into pieces that will pass in your urine. Your doctor may then place a small tube (stent) in the ureter to relieve swelling and promote healing. You may need general or local anesthesia during this procedure. Parathyroid gland surgery. Some calcium phosphate stones are caused by overactive parathyroid glands, which are located on the four corners of your thyroid gland, just below your Adam's apple. When these glands produce too much parathyroid hormone (hyperparathyroidism), your calcium levels can become too high and kidney stones may form as a result. Hyperparathyroidism sometimes occurs when a small, benign tumor forms in one of your parathyroid glands or you develop another condition that leads these glands to produce more parathyroid hormone. Removing the growth from the gland stops the formation of kidney stones. Or your doctor may recommend treatment of the condition that's causing your parathyroid gland to overproduce the hormone.

Rheumatic heart disease (RHD) is the most common acquired heart disease in children in many countries of the world, especially in developing countries. The global burden of disease caused by rheumatic fever currently falls disproportionately on children living in the developing world, especially where poverty is widespread. RHD is a chronic heart condition caused by rheumatic fever that can be prevented and controlled. Rheumatic fever is caused by a preceding group A streptococcal (strep) infection. Treating strep throat with antibiotics can prevent rheumatic fever. Moreover, regular antibiotics (usually monthly injections) can prevent patients with rheumatic fever from contracting further strep infections and causing progression of valve damage. Consequences of rheumatic heart disease Acute rheumatic fever primarily affects the heart, joints and central nervous system. The major importance of acute rheumatic fever is its ability to cause fibrosis of heart valves, leading to crippling valvular heart disease, heart failure and death. The decline of rheumatic fever in developed countries is believed to be the result of improved living conditions and availability of antibiotics for treatment of group A streptococcal infection. Overcrowding, poor housing conditions, undernutrition and lack of access to healthcare play a role in the persistence of this disease in developing countries.