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Binding and Fusion: HIV begins its life cycle
when it binds to a CD4 receptor and one of two
co-receptors on the surface of a CD4+
Tlymphocyte. The virus then fuses with the host
cell. After fusion, the virus releases RNA, its
genetic material, into the host cell.
Reverse Transcription: An HIV enzyme
called reverse transcriptase converts the singlestranded HIV RNA to double-stranded HIV DNA.
Integration: The newly formed HIV DNA
enters the host cell's nucleus, where an HIV
enzyme called integrase "hides" the HIV DNA
within the host cell's own DNA. The integrated
HIV DNA is called provirus. The provirus may
remain inactive for several years, producing few or
no new copies of HIV
Transcription: When the host cell receives a
signal to become active, the provirus uses a host
enzyme called RNA polymerase to create copies of
the HIV genomic material, as well as shorter
strands of RNA called messenger RNA (mRNA).
The mRNA is used as a blueprint to make long
chains of HIV proteins.
Assembly: An HIV enzyme called protease cuts
the long chains of HIV proteins into smaller
individual proteins. As the smaller HIV proteins
come together with copies of HIV's RNA genetic
material, a new virus particle is assembled.
Budding: The newly assembled virus pushes out
("buds") from the host cell. During budding, the new
virus steals part of the cell's outer envelope. This
envelope, which acts as a covering, is studded with
protein/sugar combinations called HIV
glycoproteins. These HIV glycoproteins are
necessary for the virus to bind CD4 and coreceptors. The new copies of HIV can now move
on to infect other cells.
Hemophilia A, also called factor VIII (FVIII) deficiency or classic hemophilia, is a genetic disorder caused by missing or defective factor VIII, a clotting protein. Although it is passed down from parents to children, about 1/3 of cases are caused by a spontaneous mutation, a change in a gene. According to the US Centers for Disease Control and Prevention, hemophilia occurs in approximately 1 in 5,000 live births. There are about 20,000 people with hemophilia in the US. All races and ethnic groups are affected. Hemophilia A is four times as common as hemophilia B while more than half of patients with hemophilia A have the severe form of hemophilia.
How do you make a working human heart? Scientists can turn stem cells into beating heart cells, but getting them to organize into a 3D heart requires a scaffold. At the Massachusetts General Hospital in Boston, Harald Ott and his team are reusing the scaffold that nature provides. They’re stripping away all the living cells from dead hearts, before filling in the leftover matrix with healthy new cells. In this video, Brendan Maher finds out how the technique could be used to develop parts of the heart, like the aortic root and valve, for transplant.
Intestinal malrotation is a developmental anomaly that occasionally causes an unusual array of symptoms in adults. The delay in diagnosis that is common in patients with malrotation frequently results in a ruptured appendix. Appendicitis should be considered when characteristic signs and symptoms are present, even if the location of abdominal pain is atypical.
protecting the body from damage caused by hyperglycemia cannot be overstated. In the United States, 57.9% of diabetic patients have one or more diabetes complications, and 14.3% have three or more.1 Strict glycemic control is the primary method of reducing the development and progression of microvascular complications, such as retinopathy, nephropathy, and neuropathy. Aggressive treatment of dyslipidemia and hypertension decreases macrovascular complications.2-4 Glycemic Control There are two primary techniques available for physicians to assess the quality of a patient’s glycemic control: self-monitoring of blood glucose (SMBG) and interval measurement of hemoglobin A1c (HbA1c).
This procedure describes one of the most versatile approaches to the anterior skull base for large tumors of the sinonasal cavity. It may be used with or without a craniofacial resection. The benefits of this approach are: wide access around the tumor; good postoperative cosmesis; & decreased operative & postoperative morbidity. We have used this approach for many bilateral tumors of the nasal & sinus cavities that approach &/or invade the skull base & brain. This video show the resection of a large esthesioneuroblastoma.
This video: Rhomboid muscle strain and spasm causes upper back pain between the shoulder blades. Some patients describe the muscle spasms and discomfort as knots in the back. Early treatment is important to speed healing and recovery. Ice therapy for the first few days followed by moist heat can help relieve symptoms.Oct 12, 2015