BOOK REVIEWS 99

human populations. As such, it is suitable for undergraduate and graduate classes in human ecology. However, a conclusion one could draw from the volume is that season- ality as a general problem in human ecology remains poorly understood. This is in part due to the fact that seasonality is strongly behaviorally and culturally mediated. Thus its study would profit from more explicitly biocultural analyses. Without an apprecia- tion of intervening behavioral variables, the effects of seasonality may appear to be sig- nificant or insignificant in different studies. In other words, natural seasonal phenom- ena (e.g., rainfall) serve as proxies for more mechanistic factors (e.g., food shortage, la- bor outputs, infectious disease prevalence, etc.). Making clear these exact links would allow us to understand how seasonal changes in human biology can change as a function of other interventions. It is also worth noting that the very essence of sea- sonality-hange itself-is not dealt with in this volume. That is, rather than focusing on the biological effects of specific factors that are seasonal, perhaps the study of seasonal- ity would benefit from an attempt to under- stand how change-recurrent and mild, re- current and severe-might have long-term effects on human biology and thus presents an opportunity for adaptation.

ANDREA WTLEY Department of Sociology and Anthropology James Madison University Harrisonhurg, Virginia

Growth Factors. By J.K. Heath. x + 75 pp. Oxford: Oxford University Press. 1993. $14.95 (paper).

This is an information-packed monograph from the I n Focus series designed as “an up- to-date introduction” for undergraduates, research scientists, and clinicians. It is di- vided into four sections comprising a review of cell proliferation, description of the growth factors, description of the growth factor receptors and signals, and discussion of nuclear response mechanisms. There is a useful abbreviations list and a glossary, es- sential for the type of individual who would use this monograph as an introduction to the field. As a clinical investigator in growth, I found much useful information

which I will return to, and I will loan this to beginning fellows with certain caveats.

Inherent in any publication in such a fast moving field, much of the material is al- ready outdated, with the latest references being 1991. For example, the discussion of postreceptor mechanisms does not include the important Janus family of tyrosine kin- ases, the growth hormone and prolactin receptors are not recognized as members of the cytokine family, and the exciting newly discovered retinoid-x receptor does not ap- pear.

In the discussion of the phenomenon of cellular senescence, the author appears to have missed the point of the Hayflick phe- nomenon, that the numbers of cell doublings in vitro correlate with the age of the donor. In the discussions of insulin-like growth-fac- tor (IGF), IGF-I1 is portrayed as a relatively insignificant substance postnatally. In fact, there is three times as much IGF-I1 circulat- ing at all ages as IGF-I. He also indicates that the IGF-I1 receptor is a tyrosine kinase heterodimeric molecule, as are the insulin and IGF-I receptors. IGF-11 binds preferen- tially to the type I1 receptor which is struc- turally unrelated to the insulin and IGF-I receptors, although the effects of IGF-I1 may be partially or largely through cross-reactiv- ity with the type I (IGF-I) or insulin recep- tors. In the glossary, the definition of endo- crine as a system in which a signal produced by a cell acts upon an anatomically remote target cell is insufficiently precise; this defi- nition could just as well apply to the nervous system. The abbreviations list refers to TRE as the TPA response element but does not define TPA.

The author favors a pedantic style which includes an abundance of run-on sentences and results in difficult reading.

In sum, this monograph contains much useful information, but is a difficult read, and is inevitably outdated in a fast moving field. Up-to-date reviews of the topics pre- sented here are available from such sources as the Journal of Clinical Endocrinology and Metabolism and Trends in Endocrinol- ogy and Metabolism, although the entire scope will not be found in a single review, as attempted here.

ARLAN L. ROSENBLOOM Department of Pediatrics University of Florida Gainesuille, Florida