1. This is a carefully done study and the findings are of considerable interest. A few minor revision are list below.
2. This is a well-written paper containing interesting results which merit publication. For the benefit of the reader, however, a number of points need clarifying and certain statements require further justification. There are given below
3. Although these observation are interesting, they are rather limited and do not advance our knowledge of the subject sufficiently to warrant publication in PNAS. We suggest that the authors try submitting their findings to specialist journal such as –
4. Although this paper is good, it would be ever better if some extra data were added
5. This manuscript is not suitable for publication in the journal of – because the main observation it describe was reported 3 years ago in a reputable journal of - .
6. Please ask someone familiar with English language to help you rewrite this paper. As you will see, I have made some correction at the beginning of the paper where some syntax is not satisfactory.
7. We feel that this potentially interesting study has been marred by an inability to communicate the finding correctly in English and should like to suggest that the authors seek the advice of someone with a good knowledge of English, preferable native speaker.
8. The wording and style of some section, particularly those concerning HPLC, need careful editing. Attention should be paid to the wording of those parts of the Discussion of and Summary which have been underlined.
9. Preliminary experiments only have been done and with exception of that summarized in Table 2, none has been repeated. This is clearly unsatisfactory, particularly when there is so much variation between assays.
10. The condition of incubation are poorly defined. What is the temperature? Were antibody used?