Review of Nucleic Acid and Protein Chemistry

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A prerequisite to understanding, designing and troubleshooting virtually any aspect of recombinant DNA technology is to appreciate the structure of nucleic acids and their building blocks, nucleotides. Having a firm grasp on concepts like complementary base pairing, the antiparallel nature of duplex DNA (or RNA) and phosphodiester linkages must preceed manipulation of these macromolecules.
Similarly, understanding the basics of protein structure is essential to many of the applications of recombinant DNA technology. If you want to alter the function of a protein, you certainly need to appreciate at least something of how structure relates to function.
This section does not provide a detailed description of nucleic acid or protein chemistry. Rather, the goal is to provide concepts that are considered fundamental for the biotechnologist.
Core concepts for this review of biochemical structure are presented as the following topics:

SKIN MENIFESTATIONS IN HYPERLIPIDEMIA

-Severe hyperlipidemia, particularly primary forms of hyperlipidemia, can be associated with lipid deposits in the skin and in joints. However, a corneal arcus, an arcus lipoides, and may be present with normal cholesterol levels after the age of 40.

-Tendon xanthoma and palmar xanthoma occur in some of the primary dyslipoproteinemias.
Tendinous xanthomas are nodose, subcutaneous lesions attached to ligaments and tendons, particularly the Achilles tendon due to accumulations of lipid-laden macrophages (foam cells) in tendons.
The nodules may be yellowish, but are usually skin colored. They are often associated with other xanthomas, and indicate the presence of hypercholesterolemia or other lipid abnormality.

A 20-year-old student has a macular rash, generalized lymphadenopathy, apthous ulcers, and gray-white plaques around the anal area. A dark-field examination demonstrates spirochetes.The treatment of choice for this patient?
a.Penicillin
b.Ceftriaxone
c.Tetracycline
d.Interferon alpha  

e.Erythromycin

FROSBITE

Frostbite is the damage to tissues from freezing ;The blood vessels contract and cause loss of oxygen to the affected body parts.And results formation of ice crystals within cells, rupturing the cells and leading to cell death.
It most commonly affects areas that are further away from the body core and have less blood flow. These include your feet, hands, nose, and ears.

There are three degrees of cold injury: frostnip, superficial frostbite, and deep frostbite.

The affected skin may be slightly flushed. The skin changes to white or grayish yellow as the frostbite develops. Pain is sometimes felt early but subsides later. Often there is NO pain; the part being frostbitten simply feels intensely cold and numb.

In superficial frostbite, there will be an area that looks white or grayish and the surface skin will feel hard but the underlying tissue will be soft. With deeper involvement, large blisters appear on the surface, as well as in underlying tissue, and the affected area is hard, cold and insensitive. Destruction of the entire thickness of the skin will necessitate skin grafting and will constitute a medical emergency, because gangrene may result from loss of blood supply to the injured part.

CLUBBLING the procces

It is described clinically as a bulbous uniform swelling of the soft tissue of the terminal phalanx of a digit with subsequent loss of the normal angle between the nail and the nail bed.

Since Hippocrates first described digital clubbing in patients with empyema, digital clubbing has been associated with various underlying pulmonary, cardiovascular, neoplastic, infectious, hepatobiliary, mediastinal, endocrine, and gastrointestinal diseases. Finger clubbing also may occur, without evident underlying disease


CLUBBING CAUSES:..................CLUBBING

A 62-year-old female is brought to the emergency room by her husband with complaints of shortness of breath. Which of the following physical findings would be the most reliable indicator that she is experiencing heart failure?
a) A third heart sound (S3)
b) A fourth heart sound (S4)
c) Ascites
d) Orthopnea