EXHIBIT 10.8
                                                                    ------------

                              AMENDED AND RESTATED
                                 LOAN CONVERSION
                                       AND
                             COMMON STOCK AGREEMENT

THE ORIGINAL LOAN CONVERSION AND COMMON STOCK AGREEMENT  ("Agreement")  made and
effective July 31, 2000 by and between MedSolutions, Inc.(MSI) formerly known as
EnviroClean  International,  Inc. or Advanced EnviroTech Systems, Inc., and Mark
M.  Altenau,  M.D.  ("Altenau"),  the  Parties is hereby  AMENDED  AND  RESTATED
effective July 31, 2001.

Prior to July 31, 2000 MSI was indebted to Altenau in the amount of  One-Million
and no/100 Dollars  ($1,000,000.00)  for funds previously  loaned to MSI with an
extended maturity date of May 31, 2001 plus accrued interest.

MSI agreed to convert  such prior debt to Altenau into shares of common stock of
MSI as set forth below.

NOW THEREFORE, MSI and Altenau agreed as follows:

1. DEFINITIONS.

         A.       "Obligation". All of the interest, principal and other amounts
                  payable  under the Notes and  Agreements  between the parties,
                  dated prior to March 31, 1999, repayment of which was extended
                  until May 31, 2001, under a Loan Extension Agreement dated May
                  31, 1999.

         B.       "Extension".  The due and  payable  date on  above  referenced
                  notes was extended to May 31, 2001.

         C.       "Interest". The annual percentage rate of interest shall be no
                  more than ten percent (10%) per annum.

         D.       "Conversion".  All of the unpaid loan  principal  amounting to
                  One-Million and no/100 Dollars  ($1,000,000.00)  was converted
                  into   One-Million-Eight-Hundred-Fifty-Thousand    (1,850,000)
                  shares of ENVI Common  Stock par value  $0.001 per share at an
                  average price of fifty-four and five hundreth cents  ($0.5405)
                  per share.

         E.       "Accrued  interest".  All accrued interest associated with the
                  unpaid  loan to July 31,  2000 was paid to Altenau in the form
                  of     a     new      loan      in     the      amount      of
                  One-Hundred-Sixteen-Thousand-Six-Hundred-Sixty-Six Dollars and
                  Sixty-Seven  cents  ($116,666.67),   said  new  loan  to  bear
                  interest at no more than ten percent (10%) per annum and to be
                  payable on July 31, 2002.

         F.       "New Loan".  New loan will be secured by the  so-called  "IMCO
                  Contract being  negotiated  with the Kingdom of Saudi Arabia,"
                  specifically  from the royalties from the sale of an estimated
                  twenty (20) EnviroClean EC-500 Systems to said customer and by
                  the  patented  technology  known  as the  EnviroClean  Thermal
                  Oxidation.

         G.       "Repayment/Conversion."  No principal payments on the new loan
                  are allowed for a period of twenty-four  (24) months from July
                  31,  2000  until July 31,  2002.  The new loan  principal  and

<PAGE>

                  accrued  interest  thereon was convertible into shares of ENVI
                  Common  Stock  par value  $0.001  per share at the rate of One
                  dollar and Fifty cents ($1.50) per share on a pre split basis.

         H.       "Cash   Investment."  In  consideration   for  accepting  this
                  agreement,   Altenau   agreed  to  make  an  additional   cash
                  investment  in the  following  amount on July 31, 2000: A cash
                  investment of Fifty-Thousand  and no/100 Dollars  ($50,000.00)
                  in exchange for  Fifty-Thousand  (50,000) shares of MSI Common
                  Stock par  value  $0.001  per  share at a price of One  dollar
                  ($1.00) per share.

         I.       "Further Cash Investment." In consideration for Altenau making
                  further  cash loans or advances  available  to MSI for working
                  capital or other purposes during any period subsequent to July
                  31, 2000, Altenau and MSI amend this agreement as follows: (1)
                  that such further loans or advances be added to the balance of
                  the new loan principal and accrued interest discussed in items
                  C and E through  G above,  (2) that the  conversion  price per
                  share of the total of all loans and advances  plus any accrued
                  interest  thereon  be  changed  to permit  the  principal  and
                  accrued  interest  thereon to be converted  into shares of MSI
                  Common  Stock  par value  $0.001  per share at the rate of One
                  dollar and Twenty Five cents  ($1.25) per share,  and (3) that
                  the security  for the loans and advances and accrued  interest
                  thereon  be  extended  to  include  all  other   tangible  and
                  intangible  property  and assets of MSI and of any  subsidiary
                  thereof.


2. REPRESENTATIONS AND WARRANTIES OF MSI.
MSI  represents  and  warrants  to  Altenau  that  this  Agreement  is  in  full
satisfaction  of the  original  extended  obligation  to  Altenau.  MSI  further
represents  that it has used its best efforts to  negotiate on Altenau's  behalf
Altenau's right to sell up to $1,500,000.00  worth of common stock through Lilly
Beter  Capital  Group,  Inc.  (LBCG)  following  the  issuance  of the LBCG Firm
Commitment  Letter to ENVI by LBCG  under the terms  specified  in the Letter of
Intent dated June 26, 2000 and a successful Form SB10  registration by MSI which
results in MSI becoming a publicly traded stock on the OTC markets.

3. FINAL AGREEMENT.

This Amended and Restated Loan Conversion and Common Stock Agreement constitutes
the final agreement and understanding  between the parties on the subject matter
hereof and supersedes  all prior  understandings  or agreements  whether oral or
written.  This Agreement may be modified only by a further  writing that is duly
executed by both parties.

4. HEADINGS.
Headings used in this Amended and Restated Loan  Conversion and Preferred  Stock
Agreement  are provided for  convenience  only and shall not be used to construe
meaning or intent.

IN WITNESS WHEREOF, Mark M. Altenau,  M.D. and MedSolutions,  Inc. have executed
this Amended and Restated Loan Conversion and Common Stock Agreement on July 31,
2001.


                                               MEDSOLUTIONS, INC.


/s/ MARK ALTENAU                               By:  /s/ MATTHEW H. FLEEGER
------------------                                 -----------------------------
Mark Altenau, M.D.                                 Matthew H. Fleeger, President