Microscope history

Like many inventions today there are disputes in origins of the original inventors. The same dispute applies to who invented the microscope.

Dating back to the first century when glass was first invented, the Roman's were investigating the use of glass and how viewing objects through it, made the objects appear larger.

Then, in the 13th Salvino D'Armate from Italy, made the first eye glass, providing the wearer with an element of magnification to one eye.

The earliest simple forms of magnification were magnifying glasses, usually about 6x - 10x and were used for inspecting tiny insects such as fleas, hence these early magnifiers called "flea glasses".

Zacharias Jansen and the first compound microscope

Then, during the 1590's, two Dutch spectacle makers, Zacharias Jansen and his father Hans started experimenting with these lenses. They put several lenses in a tube and made a very important discovery. The object near the end of the tube appeared to be greatly enlarged, much larger than any simple magnifying glass could achieve by itself.

Their first microscopes were more of a novelty than a scientific tool since maximum magnification was only around 9x and the images were somewhat blurry. Although no Jansen microscopes survived, an instrument made for Dutch royalty was described as being composed of "3 sliding tubes, measuring 18 inches long when fully extended, and two inches in diameter". The microscope was said to have a magnification of 3x when fully closed, and 9x when fully extended.

ALS

  

What is amyotrophic lateral sclerosis?

Amyotrophic lateral sclerosis (ALS), sometimes called Lou Gehrig's disease, is a rapidly progressive, invariably fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles (muscle action we are able to control, such as those in the arms, legs, and face). The disease belongs to a group of disorders known as motor neuron diseases, which are characterized by the gradual degeneration and death of motor neurons.

?how to socialize better

Highly confident people believe in their ability to achieve. If you don’t believe in yourself, why should anyone else put their faith in you? To walk with swagger and improve your self-confidence, watch out for these fifteen things highly confident people don’t do.

1. They don’t make excuses.

Highly confident people take ownership of their thoughts and actions. They don’t blame the traffic for being tardy at work; they were late. They don’t excuse their short-comings with excuses like “I don’t have the time” or “I’m just not good enough”; they make the time and they keep on improving until they are good enough.

2. They don’t avoid doing the scary thing.

Duchenne Moscular Dystrophy

Overview

In the early stages, Duchenne MD affects the shoulder and upper arm muscles and the muscles of the hips and thighs. These weaknesses lead to difficulty in rising from the floor, climbing stairs, maintaining balance and raising the arms.

What is Duchenne muscular dystrophy?

Duchenne muscular dystrophy (DMD) is a genetic disorder characterized by progressive muscle degeneration and weakness. It is one of nine types of muscular dystrophy.

DMD is caused by an absence of dystrophin, a protein that helps keep muscle cells intact. Symptom onset is in early childhood, usually between ages 3 and 5. The disease primarily affects boys, but in rare cases it can affect girls.

What are the symptoms of DMD?

Muscle weakness can begin as early as age 3, first affecting the muscles of the hips, pelvic area, thighs and shoulders, and later the skeletal (voluntary) muscles in the arms, legs and trunk. The calves often are enlarged. By the early teens, the heart and respiratory muscles also are affected. For more about DMD symptoms, see Signs and Symptoms.

Becker muscular dystrophy (BMD) is a milder version of DMD. Its onset is usually in the teens or early adulthood, and the course is slower and less predictable than that of DMD.

What causes DMD?

Duchenne muscular dystrophy was first described by the French neurologist Guillaume Benjamin Amand Duchenne in the 1860s, but until the 1980s, little was known about the cause of any kind of muscular dystrophy. In 1986, MDA-supported researchers identified a particular gene on the X chromosome that, when flawed (mutated), leads to DMD. In 1987, the protein associated with this gene was identified and named dystrophin. Lack of the dystrophin protein in muscle cells causes them to be fragile and easily damaged.

DMD has an X-linked recessive inheritance pattern and is passed on by the mother, who is referred to as a carrier. For more about the way gene mutations cause Duchenne dystrophy, see Causes/Inheritance.

What are DMD 'carriers'?

DMD carriers are females who have a normal dystrophin gene on one X chromosome and an abnormal dystrophin gene on the other X chromosome. Most carriers of DMD do not themselves have signs and symptoms of the disease, but a minority do. Symptoms can range from mild skeletal muscle weakness or cardiac involvement to severe weakness or cardiac effects and can begin in childhood or adulthood. For more, read Females and DMD in Causes/Inheritance.

What is the life expectancy in DMD?

Until relatively recently, boys with DMD usually did not survive much beyond their teen years. Thanks to advances in cardiac and respiratory care, life expectancy is increasing and many young adults with DMD attend college, have careers, get married and have children. Survival into the early 30s is becoming more common, and there are cases of men living into their 40s and 50s. For more about living with DMD, see Medical Management.

What is the status of DMD research?

MDA-supported researchers are actively pursuing several exciting strategies in DMD, such as gene therapy, exon skipping, stop codon read-through and gene repair. Human clinical trials are under way for some of these strategies. For an overview of DMD research strategies and the latest research news, see Research.

CYSTIC FIBROSIS

Reviewed August 2012

What is cystic fibrosis?

Cystic fibrosis is an inherited disease characterized by the buildup of thick, sticky mucus that can damage many of the body's organs. The disorder's most common signs and symptoms include progressive damage to the respiratory system and chronic digestive system problems. The features of the disorder and their severity varies among affected individuals.

STAINING TECHNIQUES

 Staining Techniques

Because microbial cytoplasm is usually transparent, it is necessary to stain microorganisms before they can be viewed with the light microscope. In some cases, staining is unnecessary, for example when microorganisms are very large or when motility is to be studied, and a drop of the microorganisms can be placed directly on the slide and observed. A preparation such as this is called a wet mount. A wet mount can also be prepared by placing a drop of culture on a cover‐slip (a glass cover for a slide) and then inverting it over a hollowed‐out slide. This procedure is called the hanging drop.

DNA-genes-chromosomes

DNA

DNA (or deoxyribonucleic acid) is the molecule that carries the genetic information in all cellular forms of life and some viruses. It belongs to a class of molecules called the nucleic acids, which are polynucleotides - that is, long chains of nucleotides.

Each nucleotide consists of three components:

• a nitrogenous base: cytosine (C), guanine (G), adenine (A) or thymine (T)
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• a five-carbon sugar molecule (deoxyribose in the case of DNA)
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• a phosphate molecule