Characterization of melamine-containing and calcium oxalate crystals in three dogs with suspected pet food-induced nephrotoxicosis.

The histomorphologic characteristics and chemical composition of the crystals associated with suspected pet food-induced nephrotoxicosis in 3 dogs are described. Kidney specimens from 2 dogs, a 3-year-old Parson Russell Terrier and a 3-year-old Bernese Mountain Dog, were examined. Both developed acute renal failure after eating canned pet food on the 2007 Menu Foods recall list. The third case was a kidney specimen from a 1-year-old mixed-breed dog from a similar 2004 outbreak of canine renal failure in Taiwan, which occurred after eating a commercial dog food. Hematoxylin and eosin (HE), 72-hour Oil Red O (ORO72h), Alizarin Red S (pH 4.1-4.3), and Von Kossa stains; infrared (IR) spectroscopy; and scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDXA) were performed to determine the histomorphologic characteristics and chemical composition of the crystals observed in each case. Histomorphologic findings in each case included acute, marked tubular degeneration and necrosis with many intratubular birefringent crystals, and lymphoplasmacytic interstitial nephritis. In each case, most of the crystals were rough, pale brown, and stained with ORO72h but did not stain with Alizarin Red S (pH 4.1-4.3) or Von Kossa stains; these features were consistent with a plastic or lipid. IR spectroscopy and SEM/EDXA results were consistent with melamine-containing crystals. A second crystal type identified in each case was smooth and platelike with staining characteristics and IR spectroscopy and SEM/EDXA results consistent with calcium oxalate crystals. Melamine-containing crystals have distinct light microscopic, histochemical, and SEM/EDXA characteristics that facilitate their identification in tissue.

The surgical pathology and cytopathology of US Persian Gulf War military veterans.

BACKGROUND: Tens of thousands of Persian Gulf War veterans (GWVs) have presented with medical symptoms since Operation Desert Shield and Operation Desert Storm. The Kuwait Registry at the Armed Forces Institute of Pathology was established to act as a repository for surgical pathology, cytopathology, and autopsy material from GWVs. OBJECTIVE: To identify conditions known to be endemic to the theater of operations in our cohort of GWVs. METHODS: The Kuwait Registry database was searched by computer for listed conditions endemic to the Persian Gulf region included in the registry through December 31, 1997. RESULTS: Of the 2582 patients in this cohort, 1 patient with hepatitis B and 15 patients with hepatitis C were identified. Other known endemic conditions of the Persian Gulf region were not found. CONCLUSIONS: Viral hepatitis (B and C), which is prevalent in the US population, was the only listed endemic condition identified in surgical pathology or cytopathology specimens in our cohort of GWVs.

Pathology of human immunodeficiency virus infection: infectious conditions.

Infection with the human immunodeficiency virus (HIV) and the subsequent derangement of host immunity place affected patients at risk for secondary infections. Some of the secondary pathogens occur with such frequency or are so rare in the non-immunosuppressed population that they have become part of the Centers for Disease Control and Prevention (CDC) classification for HIV/acquired immune deficiency syndrome (AIDS). Other infectious agents not yet included in the CDC definition are being reported in the HIV-infected population with increased frequency. General observations of the degree of immunosuppression associated with specific secondary infections have been useful in developing classification systems for HIV disease such as that of the CDC. However, the specific alterations in host immunity that promote infection with specific secondary pathogens are generally unknown. Geographic differences in the types and frequency of secondary infections also have been reported. Variation in strains of HIV, effect of malnutrition, lack of appropriate medical treatment, prevalence of virulent infectious diseases, and epidemiologic differences are possible contributing factors. Some infections that seemed likely to be closely associated with HIV infection have not occurred more frequently in HIV-infected patients. This review summarizes the histopathology of infectious conditions in the current CDC classification and highlights some conditions seen in HIV-infected individuals that are not currently HIV/AIDS-defining infections, yet may be seen by practicing pathologists.

Chronic fibrosing pancreatitis in childhood: report of a case and literature review.

Chronic fibrosing pancreatitis in childhood is an uncommon condition of unknown etiology with a variety of clinical presentations, histopathologic features, and outcomes. The diagnosis is one of exclusion (of hereditary or secondary pancreatitis), which should include histological assessment. The histological features of this condition have been described, to our knowledge, in nine published cases. We report a case in a 13-year-old male, who presented with obstructive jaundice and subsequently had evidence of endocrine and exocrine pancreatic insufficiency, despite a surgical decompression of the pancreatic-biliary duct system.

The effects of retinoids on cartilage differentiation in micromass cultures of chick facial primordia and the relationship to a specific facial defect.

Retinoids produce facial defects in chicken embryos. Outgrowth of the frontonasal mass with accompanying cartilage differentiation and pattern formation is inhibited. In contrast, the development of the mandibular primordia that give rise to the lower beak proceeds normally. To investigate whether the upper beak defect is based on the inhibition of cartilage differentiation specifically in the frontonasal mass, the effects of retinoids on chondrogenesis in micromass (high density) cultures of cells from facial primordia have been studied. When either 10(-6) M retinoic acid or 10(-8) M (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-napthalenyl-1- propenyl]benzoic acid (TTNPB; a stable retinoid) is added to the culture medium, cartilage differentiation is inhibited. Both frontonasal mass and mandible cultures are equally affected. The concentration of TTNPB found in both facial primordia in vivo, after a treatment that produces the defect, is also about 10(-8) M. This rules out preferential accumulation of the retinoid by the frontonasal mass as an explanation for the defect. In fact, the concentration of retinoid found in vivo, should, from the culture studies, be sufficient to markedly inhibit chondrogenesis in both the frontonasal mass and mandibles. The effects of exposure to retinoids in the intact face appear to be different to those in culture. Furthermore, when cells from retinoid-treated facial primordia are cultured in micromass, the extent and pattern of chondrogenesis in frontonasal mass cultures is identical to that of cells from untreated primordia. Cartilage differentiation in mandible cultures is slightly affected. These findings suggest that retinoids do not produce the specific facial defect by directly interfering with cartilage differentiation.

The patterns on chondrogenesis of cells from facial primordia of chick embryos in micromass culture.

Chondrogenesis of mesenchymal cells from the frontonasal mass, mandibles and maxillae of stage-24 chick embryos has been investigated in micromass (high-density) cultures. Distinct differences in the amount and pattern of cartilage differentiation are found. In cultures of frontonasal mass cells, a central sheet of cartilage develops; in cultures of mandible cells, less cartilage differentiates and nodules form; while in cultures of maxillae cells, virtually no chondrogenesis takes place. The same patterns of cartilage are found in cultures established from stage-20 embryos. At stage 28, frontonasal mass cultures form cartilage nodules and the number of nodules in mandible cultures is markedly decreased. There are striking parallels between the chondrogenic patterns of cells from the face and limb buds in micromass culture. The frontonasal mass cell cultures of stage-20 and -24 chick embryos resemble those established from the progress zone of limb buds. The progress zone is an undifferentiated region of the limb in which positional cues operate. Cultures established from the frontonasal mass of stage-28 chick embryos and from the mandibles of all stages resemble cultures of whole limb buds. These contain a mixture of committed and uncommitted cells. Ectoderm from facial primordia locally inhibits chondrogenesis in micromass cultures and this could provide a positional cue. The differences in chondrogenic potential of cells from facial primordia may underlie the specific retinoid effects on the frontonasal mass.