Other Epidemiology and Global Health Resources

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Database for QSAR of volatile organic chemicals (VOCs) - Message from Professor Alarie

  1. The database is for simple chemicals, all volatile organic chemicals of industrial importance. It was published in 1998 (copy attached).
  2. The total number of chemicals is 145 and divided in two categories, nonreactive volatile organic chemicals (nrVOCs) and reactive volatile organic chemicals (rVOCs).
  3. Each chemical was evaluated by exposing mice to known concentrations of the vapor of each chemical to obtain a concentration-response relationship for a specific effect. The potency of each chemical was obtained from linear regression analysis and the 50% response intensity was abbreviated RD50.
  4. This specific effect in mice has been described as “sensory irritation” resulting in a characteristic reflex decrease in respiratory rate due to stimulation of trigeminal nerve endings in the nasal mucosa. The potency, RD50, is the exposure concentration resulting in a decrease in respiratory rate of 50% from normal.
  5. From this database we have six orders of magnitude in potency (RD50s) for these chemicals, indicating very low to very high potencies.
  6. From the published 1998 database, you will see that we could obtain a good regression for potency for nrVOCs using physicochemical descriptors, but not for rVOCs.
  7. In 2015, an article published by Gupta et al. (copy attached) used the 1998 database, but now adding available descriptors for chemical reactivity, they were able to obtain an excellent QSAR for both nrVOCs and rVOCs.
  8. A 2016 lecture is available from the Society of Toxicology describing the above in details with the correlation of the potency in mice vs. potency in humans, also see below. This is available at the SOT site:

http://www.toxicology.org/education/edu/eminent.asp

At this site, scroll down and click on my name and then on “Recording” to start the lecture. Also you can download each slide as well as Tables 1 and 2 needed for QSAR approaches.

There is one aspect of this 1998 database which is quite important in toxicology for “safe exposure concentration for humans” for regulatory purposes or for emergency situations when such chemicals are released in accidents. Here is a brief summary:

  1. These chemicals listed in the 1998 database are widely produced, used, stored and transported. The basis for “safe exposure concentration for industrial workers” is sensory irritation. This is usually defined as Threshold Limit Values (TLVs), a list is updated and published yearly since 1946 by the American Conference of Governmental Industrial Hygienists (ACGIH). When the Occupational Safety and Health Act (OSHA) became law in 1970, the 1968 TLVs were adopted as Permissible Exposure Limits (PEL) for regulatory purposes. Other countries are using similar approaches.
  2. What has been established and published, is that there is a good correlation between a fraction of the RD50 concentration (0.03 x RD50) and the TLV concentration values for these chemicals. Therefore, with a little more work and with results from a QSAR approach, we should be able to eliminate the mouse bioassay and estimate a TLV for humans for new proposed chemicals and for many currently used chemicals for which we do not have a TLV. Provided obviously that they are VOCs.

There is also more information on this bioassay provided at the NTP site following their 2016 request for non-animal methods for acute systemic toxicity:

https://ntp.niehs.nih.gov/pubhealth/evalatm/test-method-evaluations/acute-systemic-tox/iv-data-req/index.html

On this page, scroll down and click on “Request for Data and Information…..”

At the bottom of this page you will see my name with the pdf file.

This file will provide you with a lot of information on what is available and it does also contain a link to the lecture I gave at SOT in 2016.

Another source of information is a recent article by Nielsen and Wolkoff on how sensory irritation results in humans or mice are used to established safe levels of exposure in humans (copy attached)

Let me know if you need more information or any question.

You can get another lecture prepared for students at www.pitt.edu/~rd50 by

Yves C. Alarie, Ph.D.  Professor Emeritus  University of Pittsburgh  Email:  rd50@pitt.edu 

There are other epidemiology and global health resources available, in the form of

Applying Quantitative Analysis to Development Issues conference https://www.bibalex.org/quantitativeanalysisconference/Home/Home.aspx

http://www.pcbs.gov.ps/site/lang__en/1005/default.aspx

ActivEpi Web, a free on-line interactive multi-media textbook on epidemiology concepts and methods.

ActivEpi Web can be accessed at http://activepi.herokuapp.com. The author’s website at http://www.activepi.com provides further details about the sign-up process for ActivEpi as well as freely available supporting materials including Power-Point presentations that can be used for classroom instruction. Also, this latter website describes how to freely access ActivEpi Espanol, which is a translation of the CD ROM into Spanish.

 

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Journals

 

The Central Asian Journal of Global Health (CAJGH), Official Journal of the Global Health Network Supercourse project

The Central Asian Journal of Global Health is the first official journal of the Global Health Supercourse network of over 50,000 individuals in 174 countries and a library of over 5200 lectures in public health and medicine. Our aim is to develop one of the leading journals in Central Asia and the world. The website is - http://cajgh.pitt.edu  


    NEW JOURNAL - Public Health Reviews

    Public Health Reviews was a journal published for approximately 30 years in Israel that has subsequently gone out of print. Our current mission is to relaunch the journal aiming for a broader scope and impact than the original. The journal will be published on a semesterly basis. PHR will be open source, available freely online, with printed copies provided for a fee.

    The website is www.publichealthreviews.eu

Conferences and Meetings

http://www.wcdrr.org/

Books

Other Internet Resources