UTMB Department of Pathology

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Comparative and Environmental Pathology

My directions in pathology are influenced by lifelong interests in comparative anatomy and physiology, and ecology. In the clinical setting, these interests are expressed in studies defining the structural changes in organs over time, such as involution with age, and under the influence of modulators such as hormones and physical and chemical agents. This involves detailed histological study of clinical material derived from autopsies and surgical pathology specimens. Studies might include application of quantitative techniques, such as morphometry and computer assisted three-dimensional reconstruction.

In the research laboratory, my interests are best expressed as comparative and environmental pathology. Environment has been defined as the totality of elements affecting an individual, group, population or species. Health is the general state of well being of an organism in balance with its environment. Disease is a state of imbalance in which the organism responds to challenges or "injuries" produced by the environment. Environmental pathology is the study of the interrelationships between health and disease as they are influenced by the environment. Comparative pathology is the study of disease processes as they are influenced by variations in form and function, which are the result of adaptations taking place over the life history of the species.

The specific focus of my studies is the dolphin, an apex predator, as a monitor of the marine environment. Every year large numbers of dolphins are cast up on the beaches of the Texas Gulf Coast. My hypothesis is that these animals will accurately reflect by their diseases, by the arrays of microorganisms they carry, and the burden of toxins in their tissues, the general state of the coastal marine environment. This is important because we share that environment; we work in it, play in it, and eat its products. Stranded dolphins are collected, subjected to detailed post mortem examination, diagnosis made using both gross and microscopic methods, and toxicologic and microbiologic analyses made.

This information is correlated with age, sex, known food habits, and location of stranding to provide a comprehensive picture of the animal in its environment. Publications will address naturally occurring diseases, toxicology, and morphologic development.

1. Fuson AL, Cowan DF, Kanatous SB, Polasek LK and Davis RW: (2004) Adaptations to diving hypoxia in the heart, kidneys, and splanchnic organs of harbor seals (Phoca vitulina) J Exper Biol 206:4139-4154
2. Li T-J, Zhang Y-X, Wen J, Cowan DF, Hart, J and Xiao S-Y,: (2004) Basaloid squamous cell carcinoma of the esophagus with or without adenoid cystic features. Arch Pathol Lab Med 128:1124-1130
3. Garner MM, Schwetz S, Ramer JC, Rasmussen JM, Petrini K, Cowan DF, Raymond JT, Bossart GD and LevineGA Congenital diffuse hyperplastic goiter associated with perinatal mortality in 11 captive born bottlenose dolphins (Tursiops truncatus). J. Zoo Wildl Med 33:350-355. 2003
4. Clark LS, Cowan DF, Worthy GAJ, Haubold EM: An anatomical and pathological examination of the first recorded stranding of a Frasers dolphin (Lagenodelphis hosei) in the northwestern Gulf of Mexico. Gulf of Mexico Science, 20:3-43, 2002
5. Salahuddin S, Haque AH, Hawkins H and Cowan DF: Desmoplastic small round cell tumor of the pleura. Arch Pathol Lab Med, 126:1226-1228, 2002
6. Romano, T, Abella K, Cowan D, and Curry B., 2002. Investigation of the morphology and autonomic innervation of the lymphoid organs in the pantropical spotted, spinner, and common dolphins (Stenella attenuata, Stenella longirostris and Delphinus delphis) incidentally entangled and drowned in the tuna purse-seine fishery in the eastern tropical Pacific. Southwest Fisheries Science Center, Administrative Report LJ-02-25C. Available from NOAA/NMFS/SWFSC, 8604 La Jolla Shores Drive, La Jolla, CA, 92037
7. Cowan. D. F., and Curry BE: 2002. Histopathological assessment of dolphins necropsied onboard vessels in the eastern tropical Pacific tuna fishery. Southwest Fisheries Science Center, Administrative Report LJ-02-24C. Available from NOAA/NMFS/SWFSC, 8604 La Jolla Shores Drive, La Jolla, CA, 92037.
8. Haubold, EM, Cooper, CW Jr, Wen J, Mc Ginnis, MR, Cowan DF: Comparative morphology of Lacazia loboi (syn, Loboa loboi) in dolphins and humans. Medical Mycology 38:9-14, 2000
9. Cowan DF and Smith TL Morphology of the lymphoid organs of the bottlenose dolphin Tursiops truncatus J Anatomy 1999;194:505-517
10. Smith YL, Turnbull BS and Cowan DF: Morphology of the complex laryngeal gland in the Atlantic bottlenose dolphin, Tursiops truncatus. Anat Rec 254:98-106 1999
11. Haubold EM, Aronson JF, Cowan DF, McGinis MR and Cooper, CR: Isolation of fungal rDNA from bottlenose dolphin skin infected with Loboa loboi Med Mycol 36:263-267, 1999
12. Kanatous SB, Davis RW and Cowan DF: High aerobic capacities in the skeletal muscles of seals, sea lions and fur seals: an adaptation to diving hypoxia? J Appl Physiol 861:1247-1256, 1999
13. Sun, Z, Ying H, Lu J, Bell B, Cowan DF and Motamedi M: Automatic ultrasound determination of thermal coagulation front during tissue heating. Transactions on Ultrasonics, Ferroelectrics, and Frequency Control 1999;46:1134-1146
14. Turnbull BS, Cowan DF: Angiomatosis: a newly recognized disease of the bottlenose dolphin Tursiops truncatus from the Gulf of Mexico. Vet Path 1999;36; 28-34
15. Turnbull BS and Cowan DF: Synovial joint disease in stranded Cetaceans. J. Wildl Dis 1999;35:511-518
16. Cowan DF, Gray RZ, Campbell B: Validation of the Laboratory Information System. Arch Pathol Lab Med. 122:239-244, 1998
17. Turnbull BS and Cowan DF: Myocardial contraction band necrosis in stranded cetaceans. J Comp Path 118:317-327, 1998
18. Cowan DF: How templates improve quality and efficiency in surgical pathology. Laboratory Medicine 28: 263-267, 1997
19. Adesokan A, Adegboyega, PA, Cowan DF, Kocurek J, Neal DN Jr: The testicular "tumor" of the adrenogenital syndrome: A case report of an unusual association with myelolipoma and seminoma in a cryptorchid. Cancer 80:2120-2127, 1997
20. Kobs, DG, Crotty K, Orihuela A, and Cowan DF Renal adenomatosis in acquired renal cystic disease without dialysis. J Urol Pathol 4:273-281 1996
21. Villanueva-Meyer J, Leonard MH, Briscoe F, Cesani F, Ali SA, Rhoden S, Hove M, and Cowan D: Mammoscintigraphy with Technetium-99m-Sestamibi in suspected breast cancer. J Nucl Med 37: 926-930 1996
22. Pow-Sang M, Orihuela E, Motamedi M, Torres J Adesokan A, Cowan DF, Warren M Healing response of the canine prostate to Nd:YAG laser radiation. The Prostate 28:287-294, 1996
23. Imbing FD, Adesokan A, Adegboyega PA, Calhoun K, Cowan DF: Upper aerodigestive tract mucous membrane plasmacytosis. (Resident's Page) Arch Otol Head Neck Surg 122:1413-1415,1996
24. Orihuela E, Pow-sang M, Motamedi M, Cowan DF, Warren MM. Mechanism of healing of the human prostatic urethra following thermal injury. Urology 48:601-608, 1996
25. Orihuela E, Motamedi M, Cammack T, Torres JH, Pow-Sang M, LaHaye M, Cowan DF, Warren MM Comparison of Thermocoagulation effects of low power - slow heating vs high power - rapid heating Nd:YAG laser regimens in a canine prostate model. J Urol 153:196-200, 1995
26. Cowan DF, Smith TL Morphology of the complex lymphoepithelial organ of the anal canal ("anal tonsil") in the bottlenose dolphin Tursiops truncatus J Morphol 223:263-268 1995
27. Cowan DF, Orihuela E, Motamedi M, Pow-Sang M, Tbakhi A, LaHaye M. Histopatho-logic effects of laser radiation on the human prostate. Mod Pathol 8:716-721, 1995
28. Cowan DF: Amyloidosis in the bottlenose dolphin, Tursiops truncatus Vet Path 32:311-314 1995
29. Orihuela E, Pow-Sang M, Cammack T, LaHaye M, Cowan DF, Warren MM. Nd:YAG laser thermocoagulation of the prostate: The barbecue effect. Arch Esp de Urol 48:212-215, 1995
30. West DC, Orihuela E. Pow-sang M, Adekosan A, and Cowan DF: Villous adenoma-like lesion associated with invasive transitional cell carcinoma of the bladder. Urol Pathol 3:263-268, 1995
31. Motamedi M, Torres JH, Orihuela E, Pow-Sang M, Cowan DF, Warren MM. Laser photocoagulation of prostate: Influence of Dosimetry. Lasers Surg Med. 17:49-58, 1995
32. Orihuela E, Pow-Sang M, Johnson S, Cowan DF, Warren MM Motamedi M, Comparison of the extent of Nd:YAG and diode (810 nm) laser-induced thermal coagulation of human prostate: A histopathological analysis of acute response. SPIE Proceedings 2395:47-54 1995
33. Orihuela E, Motamedi M, Pow-Sang M, LaHaye M, Cowan DF, Warren MM. Histopathological evaluation of laser thermocoagulation in the human prostate: Optimization of laser irradiation for benign prostatic hyperplasia. J Urology 153:1531-1536, 1995
34. Pow-Sang M, Orihuela E, Motamedi M, Pow-Sang J, Cowan DF, Dyer R, and Warren M. Thermocoagulation effect of diode laser radiation in the human prostate: acute and chronic study. Urology 45: 790-794, 1995
35. LaHaye M, Motamedi M, Orihuela E, Pow-Sang M, Cowan D, Warren MM. Histological evaluaion of Nd:YAG laser irradiation of the human prostate. Lasers in Surgery and Medicine Supp 6:61, 1994
36. Kumar, D and Cowan DF: Cross-reactivity of antibodies to human antigens with tissues of the bottlenose dolphin Tursiops truncatus using immuno- peroxidase techniques. Marine Mammal Science 1994. 10:188-194
37. Kumar S, Kumar D, Cowan DF, Alperin MD Mycobacterial spindle cell pseudo-tumor of the spleen Amer J Clin Path 1994 102:863
38. Cowan DF: Involution and cystic transformation of the thymus in the bottlenose dolphin, Tursiops truncatus Vet Path 1994 31:648-653
39. Tbakhi A, Cowan DF, Kumar D and Kyle D. Recurring phyllodes tumor in aberrant breast tissue of the vulva. Amer J Surg Pathol 1993 17:946-950
40. Cowan DF. Lobo's disease in a bottlenose dolphin Tursiops truncatus from Matagorda Bay, Texas. J Wildl Dis 1993 29:488-489
41. Kumar S, Kumar D and Cowan DF: Transitional cell carcinoma with rhabdoid features. Amer J Surg Pathol 1992 16:515-521, 1992
42. Cowan DF: Implementing a regulation-compliant quality improvement program on a commercial laboratory information system. Analyt Quant Cytol Histol 14:407-414, 1992
43. Jow WW, Zeid MY, Cowan D, Malin B and DeBerry JL Renal oncocytoma: Long term followup and flow cytometric data analysis. J Surg Oncol 46:53-59 1991
44. Aferzon J, Chau RI and Cowan DF: A microcomputer-based system for three- dimensional reconstructions from tomographic or histologic sections. Analyt Quant Cytol Histol 13:80-88, 1991
45. Farahmand, S and Cowan DF: Elastosis in the normal aging breast: A histopathologic study of 140 cases. Arch Pathol Lab Med 115:1241-1246, 1991
46. Cowan DF: Quality assurance in anatomic pathology: An information systems approach. Arch Pathol Lab Med 114:129-134, 1990
47. Cowan DF and Herbert TA: Involution of the breast in women aged 50 to 104 years: a histopathological study of 102 cases. Surg Path 2:323-333, 1989
48. Green LK, Cowan DF, and Moore DG: Easy and rapid demonstration of parasites in tissues and fluids by Tinopal CBS-X. Histopathology 12:553-555, 1988.
49. Aferzon J, Chau RI and Cowan DF: A microcomputer based algorithm for digitized image simplification and information extraction. Analyt Quant Cytol Histol 10:229-234, 1988.
50. Young GP, Young I, Cowan DF, and Blei B: Reliability of fine needle aspiration biopsy in 250 lesions of the lung and mediastinum. Diag Cytopathol 3:1-7, 1987.
51. Cowan DF, Wu Brian, Young GP, and Khanna OP: Correlation of histopathologic, cytologic and flow cytometric findings in neoplastic and non-neoplastic lesions of the urinary bladder. J Urol 138:753-757, 1987
52. Boileau M, Hui KS and Cowan DF: Invasive verrucous carcinoma of the urinary bladder treated by irradiation. Urology 27:56-59, 1986
53. Young GP, Somers RG, Young I, Kaplan M, and Cowan DF: Experience with a modified fine needle aspiration biopsy technique in 533 breast cases. Diag Cytopathol 2:91-98, 1986
54. Cowan DF, Walker WA, and Brownell RL: Pathobiology of small Cetaceans stranded along southern California beaches. Ch 17, pp 323-367 Research in Dolphins MM Bryden and RJ Harrison, eds Oxford University Press, 1986
55. Close LG, and Cowan DF: Recurrent necrotizing sialometaplasia of the nasal cavity. Otolaryngol Head Neck Surg 93:422-425, 1985
56. Scott LD, Katz AR, Duke JH, Cowan DF, and Maklad NF: Oral contraceptives, pregnancy and focal nodular hyperplasia of the liver. JAMA 251:1461-1463, 1984
57. Monheit JE, Cowan DF, and Moore DG: Rapid examination of surgical specimens for fungi. Arch Pathol Lab Med 108:616-618, 1984
58. Horovitz AG, Kahlil KG, Verani RR, Guthrie AM, and Cowan DF: Primary intratracheal neurilemmoma. J Thorac Cardiovasc Surg 85:313-317, 1983
59. Cowan DF: Adaptation, maladaptation and disease. in Reproduction in captive reptiles (Symposium) JR Murphy, ed SSAR Contribution to Herpetology No.1, 1980.
60. Michie DD, Cowan DF, Cain CP, and Bell CC, Jr: Effects of implanted doppler flowmeters on femoral vein autografts. Ann Surg 183:285-291,1976
61. Arvy L and Cowan DF: Data on the renculi of Globicephala melaena. Invest Cetacea (Berne) VIII:155-163, 1975.
62. Cowan DF and Brownell RL: Gut-associated lymphoepithelial organ (anal tonsil) in the gray whale. in: Functional Anatomy of Marine Mammals vol II, pp 321-327 RJ Harrison, ed. Academic Press, 1974
63. Bowman HM, Cowan DF, Kovach G, and Hook JB: Renal effects of glucagon in Rhesus monkeys during hypovolemia. Surg Gynecol Obstet 137:937-941, 1972
64. Hirsch GH, Cowan DF, and Hook JB: Histological changes in normal and drug-induced development of renal PAH transport. Proc Soc Exp Biol Med 137:116-121, 1971.
65. Overbeck HW, Swindall BT, Cowan DF, and Fleck MD: Experimental renal hypertension in dogs. Forelimb hemodynamics. Circ Res 29:51-62, 1971
66. Boam GW, Sanger VL, Cowan DF, and Vaughan DP: Subcutaneous abscesses in Iguanid lizards. JAVMA 157:617, 1970.
67. Boam GW, Sanger VL, Cowan DF, and Vaughan DP: The pathogenicity for mice of two species of salmonella isolated from the green Iguana (Iguana iguana) JAVMA 157:689-690, 1970.
68. Cowan DF and Johnson WC: Amyloidosis in the white Pekin duck. I. Relation to social evnironmental stress. Lab Invest 23:551-553, 1970.
69. Cowan DF: Avian amyloidosis. I. General incidence in zoo birds. Path Vet 5:51-58, 1968.
70. Cowan DF: Avian amyloidosis. II. Incidence and contributing factors in the Family Anatidae. Path Vet 5:59-66, 1968
71. Cowan DF: Diseases of captive reptiles. JAVMA 153:848-859, 1968
72. Cowan DF: Abnormalities of the vasa vasorum in exotic mammals and birds. Am J Pathol 51:591-599, 1967
73. Cowan DF: Helminth parasites of the pilot whale, Globicephala melaena. (Traill 1809) J Parasitol 53:166-167, 1967
74. Cowan DF, Thurlbeck WM, and Laws RM: Some diseases of the hippopotamus in Uganda. Path Vet 4:553-567, 1967.
75. Cowan DF: Observations on the pilot whale, Globicephala melaena. Organ weight and growth. Anat Rec 155:623-628, 1966
76. Cowan DF: Pathology of the pilot whale, Globicephala melaena. A comparative survey. Arch Path 82:178-189, 1966
77. Cowan DF: Pancreatitis and pulmonary hemorrhage complicating close chest cardiac massage. CMAJ 95:976-977, 1966

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