The ABCs of Cellular Membrane Transport

This link and the website of which it is a part contain much useful information about ABC genes; an important family of genes involved in cell membrane transport functions. Quoting from the linked source (in red):

The ATP-binding cassette (ABC) genes represent the largest family of transmembrane (TM) proteins. These proteins bind ATP and use the energy to drive the transport of various molecules across all cell membranes (1–3) (Figure 1). Proteins are classified as ABC transporters based on the sequence and organization of their ATP-binding domain(s), also known as nucleotide-binding folds (NBFs).

The article goes on to explain that the NBFs, which are located on the cytoplasmic side of the cell membrane, enable a transfer of energy needed to transport certain substrates across cellular membranes. ABC proteins can be viewed as molecular pumps which primariliy pump in one direction- that direction being determined by the nature of the cell. For example, in prokaryotic organisms nutrients are pumped from the exterior of a cell to inside of it. This includes sugars, vitamins and metal ions.

There is greater complexity to flow in eukaryotic cells. ABC proteins transport compounds from inside to ouside cells but also move compounds from place to place within cells. In the cytoplasm compounds are transported to within organelles like endoplasmic reticulum or mitochondria.

References:

1. The Human ATP-Binding Cassette (ABC) Transporter Superfamily by Michael Dean; Introduction to ABC Protein and Gene Organization; http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mono_001.section.139

Reducing the Risk of Fatality from Breast Cancer by 50%

An article from Medical News Today entitled Diet And Exercise Key To Surviving Breast Cancer, Regardless Of Obesity, New UCSD Study Says, has some good news for those who have had breast cancer and wish to take measures that maximize their chances of overcoming it. From the linked article (in red):

Breast cancer survivors who eat a healthy diet and exercise moderately can reduce their risk of dying from breast cancer by half, regardless of their weight, suggests a new longitudinal study from the Moores Cancer Center at the University of California, San Diego (UCSD).

Previous studies have looked at the impact of diet or physical activity on breast cancer survival, with mixed results. This study, published in the June 10 issue of the Journal of Clinical Oncology, is the first to look at a combination of both in breast cancer.

You need not become an exercise fanatic or be forced to eat an exotic tasteless diet. Thirty minutes of walking six days a week and five servings of fruits and vegetables will do. Eating fruits and veggies more often has already proven to be beneficial in other ways. This is an added incentive.

Rheumatoid Arthritis Breakthrough?

Green Tea Compound Suppresses Factors Causing Cartilage, Bone Destruction In Arthritis is a Biocompare article which discusses the possible benefits that may be derived from a compound derived from green tea. The compound is known as epigallocatechin-3-gallate or the acronym EGCG. Its usefullness may lie in a capacity to treat rheumatoid arthritis. Rheumatoid arthritis is brought about as a result of a defective immunological response resulting in inflamation, pain and eventual destruction to bones and cartilage composing joints. It appears that the body attacks its own tissue rather than the invading pathogens it is designed to defend against.

What EGCG does is inhibit the production of specific biochemicals believed to be connected to inflamation. Two of these are interleukin-6 (IL-6) and prostaglandin E2. A related study was presented by a scientist named Dr. Salah-uddin Ahmed as part of a program of the American Society for Nutrition.

Biochemicals are involved in mechanisms, known as cell signaling pathways, which regulate immunological responses. It is such pathways that are studied in order to determine the effects of the green tea compound epigallocatechin-3-gallate. Possible future treatment of rheumatoid arthritis with EGCG are made possible by learning what specific parts of signaling pathways are inhibited and how. A next step will entail studies of mice and then perhaps humans. Further research results are awaited with anticipation.

Using Adult Stem Cells to Generate Knee Cartilage

A Science Daily article entitled System For Expanding Stem Cells To Form Cartilage Tissue Under Development offers hope to those suffering knee pain because of lost or damaged knee cartilage. Surgical procedures have been used to treat the problem but there are many disadvantages to surgery and current treatment options. Quoting from the article:

"Knee osteoarthritis affects 30 million people worldwide, causing pain and joint stiffness and in severe cases restricted mobility. The limited ability of this tissue to repair itself means that surgical intervention is usually required and over 600,000 surgical procedures are performed each year in the US.

Professor Mohamed Al-Rubeai, currently a UCD Professor of Biochemical Engineering and principal investigator with the Centre for Synthesis and Chemical Biology and UCD Conway Institute has developed an economical tissue engineering approach which could offer new possibilities for restoring damaged or lost knee cartilage tissue."


One of the current options is to grow tissue in vitro from mature cartilage cells obtained from a patient. Following cell multiplication a transplant operation would take place. The entire strategy necessitates two operations and is expensive.

A newer approach involves using adult stem cells to grow new tissue. It has the advantage of enabling greater production of cartilage tissue and lowering costs.