Radiographic evaluation of destructive periodontal disease in blue mink in relation to age and blood morphology

In this study, blood samples and jaws were collected from 2 genotypes of blue mink (n = 289) in order to examine phenotypic expression of specific characteristics of Chediak-Higashi Syndrome (C-HS). Blood samples were subjected to differential counts to assess the proportion of abnormal polymorphonuclear leukocytes characteristic for CH-S (C-HS-leukocytes). Abnormal leukocytes with characteristic signs of C-HS were found in blood smears from all mink included in this study. Four teeth in one half of the mandible (P3, P4, M1, M2) were subjected to quantitative radiographic evaluation of alveolar bone loss and tooth loss. There was a high prevalence of destructive periodontal disease among blue mink included in this study. Mild to moderate periodontal disease (defined by less than 50% alveolar bone loss related to 1 or more teeth) affected 73.7% of young mink (age = 7 mo) and 67.9% of older animals (age > or = 19 mo). Severe periodontal disease (defined by more than 50% bone loss related to one or more teeth) was not detected in mink aged 7 mo, but affected 15.3% of mink aged 19 mo and 39.6% of mink aged 31 mo. The positive relationship between age and periodontal disease was statistically significant (P < 0.01). The prevalence of tooth loss was found to be high among blue mink aged > 19 mo (21.6%) and was also significantly related to age (P < 0.01). A significant positive interaction between alveolar bone loss and tooth loss (P < 0.01), implies that the highly prevalent tooth loss in the mink was related to and possibly caused by destructive periodontal disease. There was no significant difference in the prevalence of periodontal disease between the 2 genotypes and age was found to be the only statistical predictor of poor production results (P < 0.01) in blue mink.

Characterization of spontaneous dermatitis in beige rats with IgE hyperproduction

BACKGROUND

Atopic dermatitis (AD) is a common skin disease characterized by chronic recurrent eczematous lesions, but its exact etiology and mechanism are unclear. We found that beige rats (DAbg/bg), a mutant model of Chediak-Higashi syndrome, develop skin lesions characterized by pruritus, excoriation, erosion and alopecia. We describe the beige rat and examine its possible usefulness as an AD model.

METHODS

Beige rats of 4, 8, 13, 16, 26 and 52 weeks were used. Histological analysis of the skin was performed. Plasma IgE and cytokines were measured. Th1 and Th2 cytokines and RANTES mRNA expression of skin and lymph nodes were evaluated. Passive cutaneous anaphylaxis (PCA) reactions were examined, and maximization tests were conducted.

RESULTS

Skin lesions begin to develop with increases in serum IgE levels and the expression of IL-4 mRNA in the lymph node and skin. Histologically, skin lesions are characterized by acanthosis, ulceration and inflammatory cell infiltration in the dermis. Inflammatory cells consist of CD3+, CD4+, ED1+, ED2+ and I-A+ mononuclear cells, eosinophils, degranulated mast cells and neutrophils accompanying interleukin (IL)-4, interferon (IFN)-gamma and RANTES mRNA expressions of the skin. Inflammatory cells are reduced during chronification with decreased expressions of IL-4, IFN-gamma and RANTES mRNA. In addition, the rats show a high sensitivity to PCA reactions and maximization tests.

CONCLUSIONS

Our results show that some of the skin lesions of beige rats are morphologically similar to human AD, being characterized by inflammatory cell composition in the acute phase, and increased IgE and RANTES levels. However, the inflammatory process and cytokine expression pattern are different from those in human AD.

Platelet dysfunction in Chediak-Higashi syndrome-affected cattle

A serious symptom of cattle affected with Chediak-Higashi syndrome (CHS) is a bleeding tendency. This diathesis is characterized by insufficient platelet aggregation as a result of depressed response to collagen. One possible cause for the depression is a decrease in contribution of endogenous agonists such as ADP or thromboxane A(2), which are released following collagen stimulation. However, these endogenous agonists play only a minor role in collagen-induced aggregation of bovine platelets. More importantly, activation of phospholipase C as a result of a direct action of collagen is depressed, leading to a depression of Ca(2+) mobilization, in platelets from CHS-affected cattle. Several types of collagen receptor are proposed to work in concert to induce aggregation. Among them, glycoprotein VI (GPVI) and GPIa/IIa (integrin alpha2 beta1) have been supposed to play dominant roles in collagen-induced aggregation. However, there are arguments about the role of each receptor, especially the role of GPIa/IIa, and the crosstalk between receptors. Recently, we reported that the Ca(2+) signaling produced by rhodocytin, which had been first reported to be an agonist for the collagen receptor GPIa/IIa, produced much less Ca(2+) signaling in CHS platelets than in normal ones, whereas that produced by GPVI activators was normal. These suggest that GPIa/IIa or the rhodocytin-associated pathway is impaired in CHS platelets. CHS platelets are valuable to reassess the mechanism of collagen-dependent signal transduction system and to delineate the inter-relationship among collagen receptors.

A defect in collagen receptor-Ca2+ signaling system in platelets from cattle with Chediak-Higashi syndrome

Decreased platelet aggregation to collagen is a cause for bleeding diathesis of Chediak-Higashi syndrome (CHS). We investigated whether the collagen receptor-Ca2+ signaling system was impaired in platelets from cattle affected with CHS. A collagen-induced increase in cytosolic Ca2+ ([Ca2+]i) was depressed in CHS platelets, which was accompanied by a decrease in the production of inositol 1,4,5-trisphosphate. When the influences of endogenous arachidonic acid metabolites and ADP were excluded, convulxin or collagen-related peptide, which are specific agonists for the collagen receptor GPVI, increased [Ca2+]i in both normal and CHS platelets. In contrast, rhodocytin, which was thought to activate another collagen receptor GPIa/IIa, increased [Ca2+]i in CHS platelets to a lesser extent than in normal ones. Cytochalasin D, an actin polymerization inhibitor, depressed the response to collagen or rhodocytin but not the response to convulxin. Adhesion of CHS platelets to acid soluble type I collagen, which was mediated by GPIa/IIa, was similar to that of normal platelets. These results suggest that a defect in the rhodocytin-sensitive pathway is responsible for decreasing the response to collagen in CHS platelets. It remains to be determined which receptor is associated with the mechanism.

Localization of the locus responsible for Chediak-Higashi syndrome in cattle to bovine chromosome 28

Chediak-Higashi syndrome in Japanese black cattle is a hereditary disease with prolonged bleeding time and partial albinism. In the present study, we mapped the locus responsible for the disease (CHS) by linkage analysis using microsatellite genotypes of paternal half-sib pedigrees obtained from commercial herds. Analysis revealed significant linkage between the CHS locus and marker loci on the proximal end of bovine chromosome 28. The CHS locus was mapped on the region incorporating the microsatellite markers BMC6020, BM2892, and RM016 with recombination fraction 0 and lod score 4.9-11.2. We also assigned the bovine CHS1/LYST, the homologue of the gene responsible for human Chediak-Higashi syndrome, to bovine chromosome 28 using a bovine/murine somatic cell hybrid panel. These findings suggest that a mutation in the CHS1/LYST gene is likely to be responsible for Chediak-Higashi syndrome in Japanese black cattle.

Chediak-Higashi syndrome mutation and genetic testing in Japanese black cattle (Wagyu)

Chediak-Higashi Syndrome (CHS) is an autosomal recessive disorder that affects several species including mice, humans, and cattle. Evidence based on clinical characteristics and somatic cell genetics suggests that mutations in a common gene cause CHS in the three species. The CHS locus on human chromosome 1 and mouse chromosome 13 encodes a lysosomal trafficking regulator formerly known as LYST, now known as CHS1, and is defective in CHS patients and beige mice, respectively. We have mapped the CHS locus to the proximal region of bovine chromosome 28 by linkage analysis using microsatellite markers previously mapped to this chromosome. Furthermore, we have identified a missense A:T-->G:C mutation that results in replacement of a histidine with an arginine residue at codon 2015 of the CHS1 gene. This mutation is the most likely cause of CHS in Wagyu cattle. In addition, we describe quick, inexpensive, PCR based tests that will permit elimination of the CHS mutation from Wagyu breeding herds.

Cloning of bovine LYST gene and identification of a missense mutation associated with Chediak-Higashi syndrome of cattle

An inheritable bleeding disorder with light coat color caused by an autosomal recessive gene has been reported in a population of Japanese black cattle. The disease has been diagnosed as Chediak-Higashi Syndrome (CHS) of cattle which correspond to a human inheritable disorder caused by mutation in LYST gene. To characterize the molecular lesion causing CHS in cattle, cDNAs encoding bovine LYST were isolated from a bovine brain cDNA library. The nucleotide and deduced amino acid sequences of bovine LYST had 89.6 and 90.2% identity with those of the human LYST gene, respectively. In order to identify the mutation within the LYST gene causing CHS in cattle, cDNA fragments of the LYST gene were amplified from an affected animal by RT-PCR and their nucleotide sequences were completely determined. Notably, a nucleotide substitution of A to G transition, resulting in an amino acid substitution of histidine to arginine (H2015R) was identified in the affected animal. The presence of the substitution was completely corresponding with the occurrence of the CHS phenotype among 105 members of pedigrees of the Japanese black cattle and no cattle of other populations had this substitution. These findings strongly suggested that H2015R is the causative mutation in CHS of Japanese black cattle.

Impaired cytosolic calcium mobilization and aggregation in response to collagen in platelets from Japanese black cattle with Chediak-Higashi syndrome

OBJECTIVE

To examine whether impaired aggregation of platelets from Japanese Black cattle with Chediak-Higashi syndrome (CHS) was attributable to mobilization of cytosolic Ca2+.

ANIMALS

4 healthy Japanese Black cattle and 3 Japanese Black cattle with CHS.

PROCEDURE

Aggregation and mobilization of cytosolic Ca2+ in response to various receptor agonists was measured in platelets from healthy cattle and cattle with CHS. Involvement of endogenous ADP and arachidonic acid in collagen-induced responses was examined. Cytosolic Ca2+ concentration was measured after platelets were loaded with the Ca2+ indicator fura-PE3. Platelet aggregation was measured with an aggregometer.

RESULTS

Collagen (3 to 15 micrograms/ml)-induced increases in cytosolic Ca2+ concentration and aggregation were markedly impaired for platelets from cattle with CHS, compared with values for platelets from healthy cattle. Although aggregation and the sustained phase of the cytosolic Ca2+ response to ADP were also decreased in platelets from cattle with CHS, these decreases were small, compared with those in response to collagen. A cyclooxygenase inhibitor and a phospholipase A2 inhibitor did not have any effect on peak cytosolic Ca2+ concentration or collagen-induced aggregation of platelets from healthy cattle. Responses to a P2 tau-purinoceptor antagonist suggested that decreased release of endogenous ADP was only partially involved in the impaired response to collagen among platelets from cattle with CHS.

CONCLUSIONS AND CLINICAL RELEVANCE

Marked inhibition of collagen-induced Ca2+ mobilization, rather than decreased release of endogenous substances, appeared to be the major cause of impaired platelet response to collagen and the hemorrhagic tendency in cattle with CHS.

Clinical, morphologic, and biochemical characteristics of Chediak-Higashi syndrome in fifty-six Japanese black cattle

OBJECTIVE

To characterize Chediak-Higashi syndrome (C-HS) in Japanese Black cattle.

ANIMALS

56 of 200 cattle with a bleeding disorder and giant granules in leukocytes.

PROCEDURE

Clinical observation, CBC, hemostatic screening test, platelet aggregometry, electron microscopy, platelet constituent analysis, and ophthalmoscopic examination were done.

RESULTS

Affected Japanese Black cattle had increased bleeding tendency and abnormal granules in their leukocytes. Susceptibility to infection was not increased. Cutaneous albinism was evident in 6 new-born calves, but not in most affected cattle. In all affected cattle, the tapetal fundus was pale and the nontapetal fundus was almost devoid of pigment. By electron microscopy, a remarkable decrease in the number of dense granules in platelets was observed. Functionally, collagen-induced platelet aggregation was markedly reduced.

CONCLUSIONS

This bleeding disorder was diagnosed as C-HS. With regard to susceptibility to infection, albinism, and mortality, clinical manifestations of C-HS in Japanese Black cattle were moderate, compared with C-HS in human beings and Hereford cattle.

CLINICAL RELEVANCE

Because an autosomal recessive mode of inheritance was documented and recessive homozygotes could be easily detected, C-HS in Japanese Black cattle can be controlled.

Spontaneous skin lesions in beige rats (Chediak-Higashi syndrome of rats)

Beige rats, a model animal of Chediak-Higashi syndrome (CHS), frequently developed the skin lesions consisting of crust formations and alopecia in the skin around the neck from about 4 months of age. Erosion and ulceration were also observed in advance of the skin lesions. In severe cases, the lesions spread to all of the dorsum of the trunk. Skin tissues with or without lesions were studied histopathologically in 41 beige rats comparing with normal skin from 26 age-matched DA rats. Microscopically, epidermal lesions consisted of spongiosis, pustules and erosions with crust. Inflammatory cells in pustules consisted predominantly of eosinophil, and colonization of gram-positive cocci was occasionally observed in the surface area. Mites on the epidermis were also seen in some cases. Dermal lesions were superficial perivascular inflammatory cell infiltrations of eosinophils, neutrophils and mastocytes, and edema under the epidermal lesions. Follicles in the alopecic area showed resting stage and atrophic hair germ, but inflammatory changes were slight. Morphologic characters were very similar to those of chronic eosinophilic dermatitis or spongiotic dermatitis.

Inhibition of collagen-induced platelet aggregation in Japanese black cattle with inherited platelet disorder, Chediak-Higashi syndrome

Aggregation properties of platelets were examined in Japanese Black cattle with Chediak-Higashi syndrome (CHS) and normal control cattle. Platelet aggregation induced by collagen was decreased in platelets of the cattle with CHS, but not ADP (10-20 microM), thrombin (0.5-1.0 U/ml) and phorbol-12-myristate 13-acetate (PMA, 3.2 microM). The aggregation response induced by collagen in CHS platelets lacks the change in shape which usually occurs in normal platelets. Simultaneous stimulation by collagen (10 micrograms/ml) + ADP (10 microM) is effective in restoring collagen-induced aggregating response in CHS platelet, although pretreatment of ADP (10 microM) could not restore the collagen (10 micrograms/ml)-induced aggregating response, suggesting that there is a certain threshold of stimulation intensity above which collagen-induced aggregation of CHS platelet can begin. Control normal platelets, previously exposed to ADP (10 microM) and collagen (10 micrograms/ml), showed no further response to exposure to a third aggregating agent (arachidonic acid, 5 mM). On the other hand, the final agent was able to elicit aggregating responses in CHS platelets, suggesting that the arachidonate aggregating system may be suppressed in CHS cattle, but fully activated in control animals. Furthermore, normal platelets showed a significant decrease in aggregating response to collagen when pretreated with a cyclooxygenase inhibitor, indomethacin (10(-5) M), whereas CHS platelet was insensitive to indomethacin. This indomethacin-treated normal platelet mimicked the CHS collagen-induced aggregation pattern. These data suggest that a signal transduction process from receptor-operated events to arachidonate metabolism is suppressed in collagen-induced CHS platelet aggregation.

Inheritance of Chediak-Higashi syndrome in Japanese black cattle

Fifty-six Japanese black cattle affected with Chediak-Higashi syndrome (C-HS) have been referred to Miyazaki University Veterinary Teaching Hospital during the past 12 years, and 44 pedigree records were collected. In pedigree analysis, the parents had no clinical sign, the affected dams had clinically normal calves, and approximately equal numbers of males and females were affected, we therefore considered this syndrome to be an autosomal recessive trait. Quantitative genetic analyses were then made in a restricted area. Segregation analysis by the a priori method in 8 families showed that C-HS was a simple autosomal recessive trait. Furthermore, 36 dams and their 257 offspring (including 8 C-HS affected cattle) were analyzed using population genetics in the same area. The result was the same as in the former analysis.

Primary immunodeficiencies of food animals

Although there are few, well-characterized PIDs of food animals, these diseases are important because they tend to be severe and with no cure. Most animals with PID do not receive the intensive and aggressive care required for survival: Veterinarians may be consulted only when the animals are in the terminal stages of illness; it is generally not economically practical for livestock producers or practitioners to pay for the exhaustive laboratory tests required to detect and characterize these anomalies. Another reason for the small numbers of characterized clinical cases of PID is that they are rare. It is possible, however, that intensive artificial insemination and embryo transfer could select for heterozygous carriers of these autosomal traits. As seen with bovine leukocyte adhesion deficiency, as the frequency of an allele increases in the population, the numbers of affected animals increase. Furthermore, other immunodeficient syndromes are likely to exist. Veterinarians therefore should be aware of these disorders and should seek laboratory assistance to arrive at a correct diagnosis. Because of the inheritable nature of PID, livestock producers need assistance from veterinarians to identify carriers and establish sound breeding and control programs. One positive outcome from studies of PID is that research scientists and veterinarians learn much about immune systems from these afflicted animals. In fact, these animals may become models for gene therapy or marrow reconstruction procedures.

Defective in vitro motility of polymorphonuclear leukocytes of homozygote and heterozygote Chediak-Higashi cats

The in vitro migratory responses of neutrophils of homozygote and heterozygote Chediak-Higashi cats were defective in an under-agarose assay when compared to the behavior of phagocytes of control cats. The linear distances traversed by the leading front of migrating Chediak-Higashi neutrophils toward streptococcal culture supernatant, zymosan-activated serum or buffer were reduced and smaller numbers of Chediak-Higashi phagocytes populated the resulting migration areas than did cells of control animals. The relative migration parameters of the Chediak-Higashi phagocytes, however, did not differ from the corresponding parameters of control neutrophils in the presence of streptococcal culture supernatant. Therefore, phagocytes of homozygote and heterozygote Chediak-Higashi cats recognized and responded equally well to the bacterial stimuli as did cells of control animals but traveled shorter distances primarily because of a reduced inherent motility. Similar results were also obtained when the feline phagocytes were attracted by zymosan-activated serum. In addition the relative migration parameters of the neutrophils of homozygote Chediak-Higashi cats were reduced and the normalized spatial distributions of their migrating cells were significantly different in the presence of 100% and 20% zymosan-activated serum when compared to the corresponding migration parameters of carrier and control animals. Defective recognition or responses to the higher concentrations of these host-derived attractants complicated, therefore, the already reduced inherent motility of the phagocytes of homozygote Chediak-Higashi cats.

Restoration of neutrophil and platelet function in feline Chediak-Higashi syndrome by bone marrow transplantation

Allogeneic bone marrow transplantation (BMT) was successfully performed in four Chediak-Higashi (CHS) syndrome affected cats. Preparatory regimens included selective intestinal flora decontamination, fractionated total body irradiation for myeloablation, and prophylactic treatment for graft-versus-host disease with cyclosporin A. Neutrophil chemotaxis under-agarose and whole-blood platelet aggregation/secretion were characterized prior to BMT and after engraftment of donor-origin marrow cells. Liver and kidney biopsies were obtained and evaluated by light and electron microscopy before, and at 6 months post-BMT to determine what effect BMT might have on abnormal lysosome fusion in hepatocytes and renal tubule cells. The platelet storage pool defect was resolved by day 40 post-BMT. In vitro neutrophil migration in all cats appeared to improve with time after BMT and complete restoration was evident by day 175 post-BMT. No apparent differences were evident in either the liver or the kidney at 6 months post-BMT. One cat developed seizures and one developed posterior paresis 5 months post-BMT; neurologic impairment ultimately resulted in death of two cats at 6 and 8 months post-BMT, respectively. Neurologic lesions in both cats were characterized by non-suppurative encephalitis. Allogeneic BMT successfully corrected the neutrophil migration defect and platelet storage pool deficiency but had no effect on lysosome distribution in liver and kidney cells of CHS cats.

Identification of dense granule specific membrane proteins in bovine platelets that are absent in the Chediak-Higashi syndrome

Platelets from cattle with the Chediak-Higashi syndrome (CHS) have a platelet dense granule deficiency. One hypothesis for the platelet dense granule deficiency is that the granule is simply not formed in CHS megakaryocytes (MK). Alternative hypotheses include that the granule is assembled in CHS MK but a functional amino-nucleotide-cation storage complex cannot be formed or that the dense granule or its precursor fuses with other granules. This study was undertaken to determine if membrane proteins specific for platelet dense granules can be identified in membranes of other granules in CHS platelets. Platelets were disrupted; a mixed-granule fraction and alpha-granule enriched, mitochondrial-enriched, and dense granule-enriched subfractions were obtained. Membrane proteins in these intact granules were radiolabeled and the granule underwent hypotonic lysis. Membrane proteins were extracted from granule "ghosts", separated, and then visualized by autoradiography. Three major proteins were identified in platelet dense granule membrane subfractions. Two of these proteins could be identified in membrane extracts from the mixed-granule fraction from normal platelets. They could neither be identified in extracts from the mixed granule fraction of CHS platelets nor in membranes from alpha granule-enriched and mitochondrial-enriched subfractions. The absence of dense granule membrane proteins in membranes of other organelles within CHS platelets suggests that fusion of dense granules or its precursor with other granules cannot account for the platelet dense granule deficiency in CHS platelets.

Primary and secondary lysosomes in megakaryocytes and platelets from cattle with the Chediak-Higashi syndrome

The ultrastructure of lysosomes from megakaryocytes (MK) and platelets of cattle with the Chediak-Higashi syndrome (CHS) was characterized using acid phosphatase histochemistry with beta-glycerophosphate as substrate and cerium as a capturing agent. Acid phosphatase was localized in the trans aspect of the Golgi complex and/or granules in MK at all stages of maturation. Morphometric analysis of the diameter of each lysosome was performed on MK from CHS cattle and compared to MK from normal cattle. Lysosomes in CHS MK were neither enlarged nor different with respect to classification as secondary lysosomes, which composed 35% of the lysosomes in CHS MK. Lysosomes were demonstrated in 22% of the CHS platelet sections and appeared similar to those from normal cattle, 56% of them being classified as secondary lysosomes. Why lysosomes are not enlarged in bovine CHS MK and platelets, whereas they are enlarged in most other cell types, remains unknown.

Compartmentation of 4,6-difluoro-5HT studied by nuclear magnetic resonance in normal and CHS bovine platelets

A platelet storage pool deficiency (SPD) is present in platelets from cattle with the Chediak-Higashi syndrome (CHS). The most plausible hypothesis for the SPD is that dense granule precursors are simply not formed in CHS megakaryocytes. There is, however, evidence that some recently acquired 5-hydroxytryptamine (5HT) is located in granules and that the granules have an acidic interior. To obtain a greater understanding of the processing of 5HT by SPD platelets, normal and CHS platelets were incubated with 4,6-difluoro-5HT and studied by 19F NMR at 188 mHz. Normal platelets contained 2 compartments for 4,6-difluoro-5HT as indicated by 2 well-developed resonances for each 19F. The resonances were unequal in magnitude. The predominant resonance broadened with lower temperatures and was absent in CHS bovine platelets; it was, therefore, the dense granule compartment. There was only 1 resonance for each 19F in CHS platelets. The chemical shift was identical to the minor resonance, or non-dense granule resonance, found in normal bovine platelets but the resonance width was increased, indicating that some non-dense granule 4,6-difluoro-5HT was in a more restricted environment within CHS platelets than it was in normal platelets.

Adenine nucleotides, serotonin, and aggregation properties of platelets of blue foxes (Alopex lagopus) with the Chediak-Higashi syndrome

Bleeding times, concentrations of serotonin in whole blood, and concentrations of adenine nucleotides as well as aggregation properties of platelets were examined in 18 blue foxes with Chediak-Higashi-like syndrome (CHS) and 16 controls. A claw of each ketamine-sedated fox was cut until bleeding started and the bleeding time was recorded as the time from the first to the last drop. The bleeding time was greatly increased in CHS foxes. Platelet counts of CHS foxes were normal, but aggregation induced by adenosine diphosphate (ADP), serotonin, collagen, and arachidonate was impaired. Adrenaline and serotonin was impaired. Adrenaline and serotonin potentiated the aggregatory effect of ADP on control as well as on CHS platelets. The mean concentration of ADP in CHS platelets was about one-third that in controls, whereas adenosine triphosphate (ATP) was approximately one-half that in controls. Serotonin could not, in most cases, be detected in blood of CHS foxes. These findings suggest that the prolonged bleeding time in the CHS foxes is, at least partly, due to a storage pool deficiency. The drastically reduced, and in some cases absent, aggregation of CHS platelets in response to arachidonate suggests that defective arachidonate metabolism contributes to the impaired hemostasis.

Systemic candidosis in beige mice

Systemic spread of Candida albicans after intravenous inoculation was compared in beige mice and their functionally normal littermates. The number of colony forming units (c.f.u.) recovered from the kidneys, livers, and spleens of beige mice was substantially greater (100 to 1000-fold) than the number cultured from the respective organs of their functionally normal littermates. Pre-treatment with silica did not alter the number of c.f.u. recovered from the organs of either beige mice or their normal littermates. These results are consistent with the hypothesis that normally functioning polymorphonuclear leukocytes are crucial to the innate defenses that control the proliferation of this fungus.

Storage pool deficiency in cattle with the Chédiak-Higashi syndrome results from an absence of dense granule precursors in their megakaryocytes

Platelets from cattle with the Chédiak-Higashi syndrome (CHS) have a storage pool deficiency and virtual absence of platelet dense granules. Megakaryocytes (MKs) from five control (n = 135) and five CHS (n = 133) cattle were evaluated using standard transmission electron microscopy. Osmiophilic dense granules were not observed in control or CHS MKs. In MKs from normal cattle, clear vesicles of 200- to 650-nm diameter bounded by a sharp membrane were observed. They were easily differentiated from the demarcation membrane system, endoplasmic reticulum, and alpha granules. The clear vesicles were virtually absent in MKs from CHS cattle at all stages of maturation. MKs in bone marrow samples from two control (n = 91) and two CHS (n = 61) cattle that had been processed for the uranaffin reaction were also evaluated. The clear vesicles were replaced by uranaffin-positive granules in MKs from control cattle, but positive uranaffin granules were not observed in CHS MKs. These findings indicate that the platelet dense granule storage pool deficiency in CHS cattle results from an anatomic absence of dense granule precursors in maturing and mature CHS MKs.

Lesions in Brangus cattle with Chediak-Higashi syndrome

Hair, peripheral blood leukocytes, and other tissues from two related Brangus calves with phenotypic characteristics of Chediak-Higashi syndrome were examined by light and electron microscopy. Enlarged, pleomorphic, cytoplasmic granules, morphologically compatible with lysosomes, were seen in several neutrophils, many eosinophils, renal tubular epithelial cells, and Kupffer cells. Hair shafts of the calves showed irregular distribution and clumping of melanin granules. Severe infection and a possible hemorrhagic tendency were recognized. These Brangus calves represent the third breed of cattle affected with this genetic disease.

Neutropenia in cats with the Chediak-Higashi syndrome

Thirteen cats with Chediak-Higashi syndrome and 22 control cats from the same colony, were evaluated for neutropenia. The absolute neutrophil counts of the Chediak-Higashi syndrome cats were significantly less (P less than 0.05) than those of the control cats. It is concluded that Chediak-Higashi syndrome cats, like Chediak-Higashi syndrome humans, have a neutropenia associated with the other manifestations of the syndrome. Lysozyme activity which was undetectable in the serum of both Chediak-Higashi syndrome and control cats was not of use for determining if the neutropenia was the result of neutrophil destruction.

Ultrastructure and stereology of leukocytes and platelets of normal foxes and a fox with a Chediak-Higashi-like syndrome

Peripheral blood leukocytes and platelets from five normal foxes (Vulpes vulpes) and a fox with phenotypical characteristics of Chediak-Higashi syndrome (CHS) were examined by electron microscopy. Lymphocytes, monocytes, neutrophils, eosinophils, and platelets from the affected fox contained giant membrane-bound granules that resembled lysosomes. In eosinophils and neutrophils from the affected fox and a normal fox, relative cell volume occupied by granules and number of granules per unit area were calculated. Relative cell volume occupied by granules was the same in both foxes, but there were significantly fewer granules per unit area in the affected fox. This result is consistent with the idea that the giant granules arose from fusion of pre-existing, normal-sized granules, as occurs in CHS. In platelets from the affected fox, no osmiophilic granules were seen. Our findings agree with those from studies of CHS-affected blood cells in other species.

Age-related changes of the retinal pigment epithelium of cats with Chediak-Higashi syndrome

The eyes of 7, 9, and 11-year-old Chediak-Higashi syndrome (CHS)-affected cats were examined by light, fluorescence, and electron microscopy. Numerous round to oval bodies of various sizes were associated with the retinal pigment epithelium (RPE). These bodies stained positively with periodic acid-Schiff. They also displayed a bright yellow autofluorescence and stained positively with a prolonged Ziehl-Neelsen acid-fast method for demonstration of lipofuscin, suggesting that they contained lipofuscin or a lipofuscin-like material. Ultrastructural examination disclosed the bodies to be secondary lysosomes and large to giant-sized residual bodies. Many of the residual bodies were extracellular and formed drusen-like mounds, covered by deposits of basal lamina, beneath the RPE. Also evident were scattered degenerated RPE cells and other RPE cells that had detached and migrated into the interphotoreceptor space. The presence of drusenoid bodies, and the loss of cells from the RPE monolayer in CHS eyes have not been reported previously. Many of the changes in the CHS cat eyes resemble those in non-CHS aging eyes of man and other species.

Animal model. Light and electron microscopy of hepatocytes of cats with Chediak-Higashi syndrome

Cats with a condition resembling human Chediak-Higashi syndrome (CHS) are the most recently described of five species of animals with similar syndromes. In this study, hepatocytes of cats with CHS were examined by light microscopy, histochemistry, and transmission electron microscopy. Enlarged cytoplasmic granules, morphologically consistent with lysosomes, were present in many of the CHS cat hepatocytes. The enlarged lysosomes were generally larger and more numerous in centrilobular hepatocytes and were generally larger in older cats. The lesions were similar to those reported in other species with CHS suggesting that CHS cats are a valid animal model of human CHS.

Aberrant melanosome development in the retinal pigmented epithelium of cats with Chediak-Higashi syndrome

The Chediak-Higashi syndrome is a genetic disorder characterized by greatly enlarged cytoplasmic granules, including lysosomes and melanosomes. Eyes of humans and animals with Chediak-Higashi syndrome are hypopigmented to various degrees. Intraocular melanin granules vary in size, with some being massively enlarged. Electron microscopic examination of retinal pigmented epithelium of kittens with Chediak-Higashi syndrome disclosed a number of abnormalities of premelanosomes and melanosomes. Few premelanosomes were present. Most of the melanin granules were giant sized, but their structures varied. Some of the giant granules were composed of several premelanosomes and melanosomes in different stages of maturation. Others contained randomly oriented melanofilaments between melanosomes. There were also complex giant granules consisting of both melanosomal and lysosomal components. Inappropriate fusion of cytoplasmic granules appears to be the most likely mechanism for formation of the giant granules. Fusion of premelanosomes with lysosomes and resultant destruction of the premelanosomes probably is a major cause of the ocular hypopigmentation of Chediak-Higashi syndrome.

[Chédiak-Higashi syndrome]

As the Chédiak-Higashi Syndrome (CHS) is rare in various species of mammal and occurs almost only in very young to young animals, it is virtually unknown and may therefore pass unnoticed. For this reason, the symptoms as reported for example in man, cattle, cats and mink are brought together and compared in the present paper. The most important symptoms are dilution of the pigment of skin and fur and increased susceptibility to infection. Enlarged granules are found in leukocytes and various other types of cell. The basis for this defect should be sought at the level of the microtubules. Moreover this report is concerned with genetic features of this type of defect. The criteria to be applied in the diagnosis of the CHS are discussed.

Secondary amyloidosis in a bull with Chediak-Higashi syndrome

A ten year old Hereford bull with Chediak-Higashi syndrome was examined at necropsy after a lifelong history of recurrent bacterial infections. Amyloidosis, which has not been previously reported in Chediak-Higashi, was identified in liver, spleen and kidney.

Serotonin accumulation in granules of storage pool-deficient platelets of Chediak-Higashi cattle

Platelets from cattle with the Chediak-Higashi (CH) syndrome are virtually devoid of dense granules, serotonin (5-HT), and stored ATP and ADP. The present study determined how the handling of 5-HT in normal cattle platelets differed from that in CH cattle platelets. Normal and CH platelets accumulated 5-[14C]HT to the same extent. After normal and CH platelets were incubated with 5-HT for 12 h most 5-HT is still intact, indicating that it was protected from metabolism. Part of the newly acquired 5-HT in normal and CH platelets was in a pool that was rapidly released by 5 U/ml of thrombin, suggesting that 5-HT was, in part, within granules. Subcellular fractionation studies showed that, whereas most of the newly acquired 5-HT in normal platelets was located in the dense granule fractions, about one fourth was found in the lighter granule fraction that was enriched in alpha-granules. The dense granule fraction was virtually absent in CH platelets, and most of the granule 5-HT was associated with the lighter granule fraction. The mixed granule fraction from CH platelets accumulated 5-HT but the uptake was about 10% of that from normal platelets. Unlike normal granules the uptake of 5-HT by CH granules was only slightly inhibited by reserpine but was reversed by NH4Cl and nigericin treatment.

Ultrastructure of resting and activated storage pool deficient platelets from animals with the Chédiak-Higashi syndrome

The ultrastructural of platelets from Chédiak-Higashi (CH) and normal cattle, mink, and cats at rest was studied. Platelets from CH animals had a virtual absence of platelet dense granules. Alpha granules, amorphous membrane-surrounded structures, mitochondria, and microtubules of CH bovine platelets were similar in number and appearance to those in normal bovine platelets. Giant CH granules, present in other cells and considered diagnostic of the syndrome, could not be identified in platelets from CH animals. The open canalicular system and dense tubule system were not readily identifiable in resting bovine platelets. The ultrastructure of normal and CH cattle platelets was evaluated at various stages of ADP-induced aggregation. After platelets changed shape during the first phase of aggregation, the ultrastructural appearance of CH platelets was similar to that of normal platelets. The CH platelets composing the aggregates during irreversible aggregation did not appear as activated as did normal platelets, even though the aggregation tracings were similar. Normal and CH cattle platelets treated with thrombin appeared morphologically similar and were characterized by centrifugal movement of granules.

Inheritance of the Chediak-Higashi syndrome in cats

The phenotypes with respect to the Chediak-Higashi syndrome (CHS) of 245 cats from 67 matings were analyzed. It was determined that the gene for feline CHS, like that in other species with CHS, is inherited in an autosomal recessive manner with complete penetrance. We propose the symbol ch for the gene for CHS in cats. Additional studies revealed enlarged periodic acid-Schiff positive granules in renal tubule cells in CHS cats, which provides further evidence of the homologous nature of CHS among the various species in which it occurs.

Prolonged bleeding time in Aleutian mink associated with a cyclo-oxygenase-independent aggregation defect and nucleotide deficit in blood platelets

A prolonged mean template bleeding time of 13 minutes was present in nine Aleutian mink affected with Chediak-Higashi syndrome (CHS) compared with 4 minutes in dark control mink. The concentrations of blood platelets in normal and affected animals did not differ significantly. However, in mink with CHS, a marked disturbance of platelet response to collagen was present. Administration of aspirin and indomethacin completely blocked CH platelet response to collagen. Blood platelet adenosine triphosphate and adenosine diphosphate values from mink with CHS were significantly less than those of normal mink, and the platelet adenosine triphosphate/adenosine diphosphate ratios were 10.31 in affected mink and 2.74 in normal mink. These findings are consistent with our previous investigations in affectd cattle and persons and indicate that a "storage pool disease" of platelets exist in the mink with CHS.

Characterization of platelets from normal mink and mink with the Chediak-Higashi syndrome

Bleeding times of mink with the Chediak-Higashi (CH) syndrome was markedly prolonged. Platelet counts were normal but there was an impaired platelet aggregation response to collagen. The metabolic adenine nucleotide pool of platelets from normal and CH mink was labeled with 14C-adenine and the platelets were gel-filtered. Gel-filtered platelets (GFP) from CH mink contained only 37.9% of the adenosine triphosphate (ATP) and 9.6% of the adenosine diphosphate (ADP) found in normal platelets and the ATP/ADP ratio was similar to the 14C-ATP/14C-ADP ratio. Platelet content of Ca2+, Mg2+, and in particular 5-hydroxytryptamine was decreased. When GFP were incubated with thrombin to induce maximal secretion, only negligible amounts of ATP and ADP were released. The specific activity of the extracellular nucleotides approximated that within the platelet. These findings suggest that the stored nucleotide pool in CH platelets is virtually absent and that the abnormalities in platelet function may be due, in part, to the essential absence of secretable ADP and serotonin. The release of Ca2+ and Mg2+ by CH platelets was 56% and 27.8% of normal, respectively.

Ocular manifestations of the Chédiak-Higashi syndrome in four species of animals

Ocular examinations were performed on cattle, cats, mink, and mice affected with Chédiak-Higashi syndrome (CHS). Bovine eyes were examined grossly and with an indirect ophthalmoscope, and Schirmer tear tests were performed. Feline eyes were examined grossly as well as with an indirect opthalmoscope and a slit lamp biomicroscope, and Schirmer tear tests were done on them. Postrotatory nystagmus was induced and measured in clinically normal Siamese cats, in clinically normal Persian and domestic short-haired cats, and in cats with CHS. Mink and mouse eyes were examined grossly with focal illumination. The animals with CHS had photophobia, pale irises, and fundic hypopigmentation associated with red fundic light reflections. Cats with CHS also had cataracts. Spontaneous nystagmus was observed in four of nine cats with CHS, and the duration of induced nystagmus was longer in the cats with CHS and in Siamese cats than in clinically normal cats that were not Siamese. Tear secretion appeared to be normal in all species of animals with CHS. The ocular manifestations of CHS in these animals were compared with those reported in man and were found to be similar.

Partial oculocutaneous albinism in Mystromys albicaudatus: nonhomology with the Chediak-Higashi syndrome

Partially albinic Mystromys albicaudatus were examined to determine if the condition in these animals was homologous with the Chediak-Higashi syndrome. Tissues and cells from partially albinic and normal Mystromys albicaudatus were studied by light and electron microscopy. No evidence of cytoplasmic granule enlargement, which is characteristic of the Chediak-Higashi syndrome, was detected in the cells of the partially albinic rats when compared to controls. It was concluded that the inherited condition of partial albinism of Mystromys albicaudatus was not homologous with the inherited partially albinic disease known as the Chediak-Higashi syndrome.

Reported causes of death of captive killer whales (Orcinus orca)

Inquiries were made to all oceanaria that maintain killer whales in North America. Causes of death determined at necropsy included mediastinal abscesses, pyometra, pneumonia, influenza, salmonellosis, nephritis, Chediak-Higashi syndrome, fungus infection, ruptured aorta, cerebral hemorrhage and a perforated post-pyloric ulcer. Captive females appear to have a higher rate of mortality than males. Growth rates for whales that died were greater than for those that survived.

The Chediak-Higashi syndrome of cats

Initial clinical, genetic, cytochemical and ultrastructural studies have characterized the Chediak-Higashi syndrome in cats. Three cats with Chediak-Higashi syndrome were found in a single line of 27 Persian cats, and three additional affected cats were produced from two prospective breedings of the original line. The disorder was characterized genetically as an autosomal recessive condition. All cats in the line with the combination of yellow eye color and "blue smoke" hair color exhibited the disorder. Four of the five cats examined had bilateral nuclear cataracts as early in life as 3 months of age. No increased susceptibility to infectious disease was observed. A bleeding tendency was noted. Abnormally large eosinophilic, sudanophilic, peroxidase-containing granules were observed in the neutrophils of the granulocytic series of blood and bone marrow by electron and light microscopy. Granules of eosinophils and basophils were also enlarged. Light microscopic studies of hair and skin revealed enlarged melanin granules. These manifestations were similar to those in man, mink, cattle, mice, and the killer whale with Chediak-Higashi syndrome. Cats are the sixth species in which this genetic disease has been reported.

Ultrastructural and morphometric studies of platelets from cattle with the Chediak-Higashi syndrome

This study revealed that the lesions in platelets from cattle with the Chediak-Higashi syndrome (CHS) are not morphologically analogousto those present in the other granule-containing cells in cattle and other species with CHS. There was no evidence of enlargement of the lysosomal granules in bovine CHS platelets...

The Chediak-Higashi (beige) mutation in two mouse strains. Allelism and similarity in lysosomal dysfunction

A mutation called beige, with a phenotype similar to that of the human Chediak-Higashi syndrome, has occurred independently in two inbred strains of mice. Beige-J (bgj) occurred as a spontaneous mutation in the C57B1/6J strain and beige (bg) was radiation-induced in mice of heterogenous background which were then inbred as strain SB/Le (bg/bg), the subject of the present study. As in the previously characterized C57Bl/6J beige-J mutant, there is a correlation between abnormal lysosome structure and defective lysosome function in SB/Le beige mice. They secrete much less than normal amounts of lysosomal enzymes from proximal tubule cells and, hence, have increased lysosomal enzyme activity in kidney. In addition, after treatment of either beige strain with androgen, numerous giant beta-glucuronidase-containing lysosomes are present in kidney proximal tubule cells near the corticomedullary border. By directly measuring the rate of beta-glucuronidase synthesis in androgen-treated SB/Le beige mouse kidney, it was shown that the greater accumulation of this lysosomal enzyme in proximal tubule cells was not due to an increase in its rate of synthesis. Genetic analysis of the beige mutations in the two mutant strains demonstrated that both mutant genes are recessive and, in fact, are allelic. The results suggest that both beige strains are defective in intracellular motility of lysosomes and/or their fusion with cellular membranes, and that both mutant strains are suitable experimental models for the human Chediak-Higashi syndrome.

Leukocyte dysfunction in the bovine homologue of the Chediak-Higashi syndrome of humans

The increased susceptibility to pyogenic infections noted in cattle with the Chediak-Higashi syndrome trait has been related to an impairment of leukocyte function at the cellular level. Investigations of the relationship of abnormal granule formation to increased susceptibility to infection, conducted with cell suspensions containing high concentrations of polymorphonuclear leukocytes, revealed a bactericidal defect that was associated with abnormal intracellular killing and not due to defective particle ingestion. The in vitro bactericidal defect was associated with a metabolic anomaly in the hexose monophosphate shunt, but not with an alteration in the capacity to reduce nitroblue tetrazolium dye. Ultrastructural histochemical studies of phagocytosis and phagolysosome formation in polymorphonuclear leukocytes suggest that the impairment in bactericidal capacity is correlated also with either a delay or failure of primary granules to degranulate.