Expression of the transcription factor Klf6 by thymic epithelial cells is required for thymus development

Thymic epithelial cells (TEC) control T cell development and play essential roles in establishing self-tolerance. By using Foxn1-Cre-driven ablation of Klf6 gene in TEC, we identified Klf6 as a critical factor in TEC development. Klf6 deficiency resulted in a hypoplastic thymus-evident from fetal stages into adulthood-in which a dramatic increase in the frequency of apoptotic TEC was observed. Among cortical TEC (cTEC), a previously unreported cTEC population expressing the transcription factor Sox10 was relatively expanded. Within medullary TEC (mTEC), mTEC I and Tuft-like mTEC IV were disproportionately decreased. Klf6 deficiency altered chromatin accessibility and affected TEC chromatin configuration. Consistent with these defects, naïve conventional T cells and invariant natural killer T cells were reduced in the spleen. Late stages of T cell receptor-dependent selection of thymocytes were affected, and mice exhibited autoimmunity. Thus, Klf6 has a prosurvival role and affects the development of specific TEC subsets contributing to thymic function.

A Knock-In Mouse Model of the Gcm2 Variant p.Y392S Develops Normal Parathyroid Glands

Context

The glial cells missing 2 (GCM2) gene functions as a transcription factor that is essential for parathyroid gland development, and variants in this gene have been associated with 2 parathyroid diseases: isolated hypoparathyroidism in patients with homozygous germline inactivating variants and primary hyperparathyroidism in patients with heterozygous germline activating variants. A recurrent germline activating missense variant of GCM2, p.Y394S, has been reported in patients with familial primary hyperparathyroidism.

Objective

To determine whether the GCM2 p.Y394S missense variant causes overactive and enlarged parathyroid glands in a mouse model.

Methods

CRISPR/Cas9 gene editing technology was used to generate a mouse model with the germline heterozygous Gcm2 variant p.Y392S that corresponds to the human GCM2 p.Y394S variant. Wild-type (Gcm2+/+) and germline heterozygous (Gcm2+/Y392S) mice were evaluated for serum biochemistry and parathyroid gland morphology.

Results

Gcm2 +/Y392S mice did not show any change compared to Gcm2+/+ mice in serum calcium and parathyroid hormone levels, parathyroid gland histology, cell proliferation, or parathyroid gland size.

Conclusion

The mouse model of the p.Y392S variant of Gcm2 shows that this variant is tolerated in mice, as it does not increase parathyroid gland cell proliferation and circulating calcium or PTH levels. Further investigation of Gcm2+/Y392S mice to study the effect of this variant of Gcm2 on early events in parathyroid gland development will be of interest.

Impact of large granular lymphocyte leukemia on blood DNA methylation and epigenetic clock modeling in Fischer 344 rats

Age-dependent differences in methylation at specific cytosine-guanosine sites (CpGs) have been used in "epigenetic clock" formulas to predict age. Deviations of epigenetic age from chronological age are informative of health status and are associated with adverse health outcomes, including mortality. In most cases, epigenetic clocks are performed on methylation from DNA extracted from circulating blood cells. However, the effect of neoplastic cells in the circulation on estimation and interpretation of epigenetic clocks is not well understood. Here, we explored this using Fischer 344 (F344) rats, a strain that often develops large granular lymphocyte leukemia (LGL). We found clear histological markers of LGL pathology in the spleens and livers of 27 out of 61 rats aged 17-27 months. We assessed DNA methylation by reduced representation bisulfite sequencing with coverage of 3 million cytosine residues. Although LGL broadly increased DNA methylation variability, it did not change epigenetic aging. Despite this, inclusion of rats with LGL in clock training sets significantly altered predictor selection probability at 83 of 121 commonly utilized CpGs. Furthermore, models trained on rat samples that included individuals with LGL had greater absolute age error than those trained exclusively on LGL-free rats (39% increase; p<0.0001). We conclude that the epigenetic signals for aging and LGL are distinct, such that LGL assessment is not necessary for valid measures of epigenetic age in F344 rats. The precision and architecture of constructed epigenetic clock formulas, however, can be influenced by the presence of neoplastic hematopoietic cells in training set populations.

A mouse model of Proteus syndrome

Proteus syndrome is a mosaic, progressive overgrowth disorder caused by a somatic activating variant c.49G > A p.(E17K) in AKT1. The presentation in affected individuals is variable, with a diversity of tissues demonstrating abnormalities. Common manifestations include skin and bony overgrowth, vascular malformations (VMs), cysts and benign tumors. We used two methods to create mouse models that had endogenously-regulated mosaic expression of the Proteus syndrome variant. Variant allele fractions (VAFs) ranged from 0% to 50% across numerous tissues in 44 Proteus syndrome mice. Mice were phenotypically heterogeneous with lesions rarely observed before 12 months of age. VMs were the most frequent finding with a total of 69 found in 29 of 44 Proteus syndrome mice. Twenty-eight cysts and ectasia, frequently biliary, were seen in 22 of 44 Proteus syndrome mice. Varying levels of mammary hyperplasia were seen in 10 of 16 female Proteus syndrome mice with other localized regions of hyperplasia and stromal expansion noted in several additional animals. Interestingly, 27 of 31 Proteus syndrome animals had non-zero blood VAF that is in contrast to the human disorder where it is rarely seen in peripheral blood. Identification of variant-positive cells by green fluorescent protein (GFP) staining in chimeric Proteus syndrome mice showed that in some lesions, hyperplastic cells were predominantly GFP/Akt1E17K-positive and showed increased pAKT signal compared to GFP-negative cells. However, hyperplastic mammary epithelium was a mixture of GFP/Akt1E17K-positive and negative cells with some GFP/Akt1E17K-negative cells also having increased pAKT signal suggesting that the variant-positive cells can induce lesion formation in a non-cell autonomous manner.

Cerebrospinal Fluid-Directed rAAV9-rsATP7A Plus Subcutaneous Copper Histidinate Advance Survival and Outcomes in a Menkes Disease Mouse Model

Menkes disease is a lethal neurodegenerative disorder of copper metabolism caused by mutations in an evolutionarily conserved copper transporter, ATP7A. Based on our prior clinical and animal studies, we seek to develop a therapeutic approach suitable for application in affected human subjects, using the mottled-brindled (mo-br) mouse model that closely mimics the Menkes disease biochemical and clinical phenotypes. Here, we evaluate the efficacy of low-, intermediate-, and high-dose recombinant adeno-associated virus serotype 9 (rAAV9)-ATP7A delivered to the cerebrospinal fluid (CSF), in combination with subcutaneous administration of clinical-grade copper histidinate (sc CuHis, IND #34,166). Mutant mice that received high-dose (1.6 × 1010 vg) cerebrospinal fluid-directed rAAV9-rsATP7A plus sc copper histidinate showed 53.3% long-term (≥300-day) survival compared to 0% without treatment or with either treatment alone. The high-dose rAAV9-rsATP7A plus sc copper histidinate-treated mutant mice showed increased brain copper levels, normalized brain neurochemical levels, improvement of brain mitochondrial abnormalities, and normal growth and neurobehavioral outcomes. This synergistic treatment effect represents the most successful rescue to date of the mo-br mouse model. Based on these findings, and the absence of a large animal model, we propose cerebrospinal fluid-directed rAAV9-rsATP7A gene therapy plus subcutaneous copper histidinate as a potential therapeutic approach to cure or ameliorate Menkes disease.

Outbreak of Opportunistic Ascending Pyelonephritis with Numerous Yeast after Experimental Humanization Surgery in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ and NOD.Cg-Rag1tm1Mom Il2rgtm1Wjl/SzJ Immunodeficient Mice

Unexpected mortality occurred in a group of 12 NOD.Cg-NOD.Cg-Prkdc^scidIl2rg^tm1Wjl/SzJ (NSG) and 12 NOD.Cg-Rag1^tm1Mom Il2rg^tm1Wjl/SzJ (NRG) immunodeficient mice. At 10 d after routine bone marrow-liver-thymus humanization surgery, 9 mice were found dead without observation of initiating clinical signs; 1 d later (day 11), 3 additional mice showed signs of morbidity, including severe hunching, lateral recumbency, slow movement, shallow respiration, and decreased response to external stimulus. All remaining mice rapidly decompensated and were found dead or were euthanized within 4 d after the first death. Histopathology revealed severe ascending pyelonephritis with numerous yeast. Cultures in some mice were positive for Enterococcus faecalis or Staphylococcus xylosus, 2 bacteria considered commensals in rodents. In addition, Candida albicans was cultured from some animals. Further investigation revealed that a restraining device used for tail vein injections was the likely fomite harboring Candida organisms. These findings indicate that ascending pyelonephritis, with Candida as the etiologic agent, can cause significant mortality in NSG and NRG immunodeficient mice.

Conditional deletion of nonmuscle myosin II-A in mouse tongue epithelium results in squamous cell carcinoma

To investigate the contribution of nonmuscle myosin II-A (NM II-A) to early cardiac development we crossed Myh9 floxed mice and Nkx2.5 cre-recombinase mice. Nkx2.5 is expressed in the early heart (E7.5) and later in the tongue epithelium. Mice homozygous for deletion of NM II-A (A^Nkx/A^Nkx) are born at the expected ratio with normal hearts, but consistently develop an invasive squamous cell carcinoma (SCC) of the tongue (32/32 A^Nkx/A^Nkx) as early as E17.5. To assess reproducibility a second, independent line of Myh9 floxed mice derived from a different embryonic stem cell clone was tested. This second line also develops SCC indistinguishable from the first (15/15). In A^Nkx/A^Nkx mouse tongue epithelium, genetic deletion of NM II-A does not affect stabilization of TP53, unlike a previous report for SCC. We attribute the consistent, early formation of SCC with high penetrance to the role of NM II in maintaining mitotic stability during karyokinesis.

Epidermal growth factor receptor as a novel molecular target for aggressive papillary tumors in the middle ear and temporal bone

Adenomatous tumors in the middle ear and temporal bone are rare but highly morbid because they are difficult to detect prior to the development of audiovestibular dysfunction. Complete resection is often disfiguring and difficult because of location and the late stage at diagnosis, so identification of molecular targets and effective therapies is needed. Here, we describe a new mouse model of aggressive papillary ear tumor that was serendipitously discovered during the generation of a mouse model for mutant EGFR-driven lung cancer. Although these mice did not develop lung tumors, 43% developed head tilt and circling behavior. Magnetic resonance imaging (MRI) scans showed bilateral ear tumors located in the tympanic cavity. These tumors expressed mutant EGFR as well as active downstream targets such as Akt, mTOR and ERK1/2. EGFR-directed therapies were highly effective in eradicating the tumors and correcting the vestibular defects, suggesting these tumors are addicted to EGFR. EGFR activation was also observed in human ear neoplasms, which provides clinical relevance for this mouse model and rationale to test EGFR-targeted therapies in these rare neoplasms.

Failure-to-thrive syndrome associated with tumor formation by Madin-Darby canine kidney cells in newborn nude mice

Tumors that formed in newborn nude mice that were inoculated with 10(7) Madin-Darby canine kidney (MDCK) cells were associated with a failure-to-thrive (FTT) syndrome consisting of growth retardation, lethargy, weakness, and dehydration. Scoliosis developed in 41% of affected pups. Pups were symptomatic by week 2; severely affected pups became moribund and required euthanasia within 3 to 4 wk. Mice with FTT were classified into categories of mild, moderate, and severe disease by comparing their weight with that of age-matched normal nude mice. The MDCK-induced tumors were adenocarcinomas that invaded adjacent muscle, connective tissue, and bone; 6 of the 26 pups examined had lung metastases. The induction of FTT did not correlate with cell-line aggressiveness as estimated by histopathology or the efficiency of tumor formation (tumor-forming dose 50% endpoint range = 10(2.8) to 10(7.5)); however, tumor invasion of the paravertebral muscles likely contributed to the scoliosis noted. In contrast to the effect of MDCK cells, tumor formation observed in newborn mice inoculated with highly tumorigenic, human-tumor-derived cell lines was not associated with FTT development. We suggest that tumor formation and FTT are characteristics of these MDCK cell inocula and that FTT represents a new syndrome that may be similar to the cachexia that develops in humans with cancer or other diseases.

L-threo-dihydroxyphenylserine corrects neurochemical abnormalities in a Menkes disease mouse model

OBJECTIVE

Menkes disease is a lethal neurodegenerative disorder of infancy caused by mutations in a copper-transporting adenosine triphosphatase gene, ATP7A. Among its multiple cellular tasks, ATP7A transfers copper to dopamine beta hydroxylase (DBH) within the lumen of the Golgi network or secretory granules, catalyzing the conversion of dopamine to norepinephrine. In a well-established mouse model of Menkes disease, mottled-brindled (mo-br), we tested whether systemic administration of L-threo-dihydroxyphenylserine (L-DOPS), a drug used successfully to treat autosomal recessive norepinephrine deficiency, would improve brain neurochemical abnormalities and neuropathology.

METHODS

At 8, 10, and 12 days of age, wild-type and mo-br mice received intraperitoneal injections of 200μg/g body weight of L-DOPS, or mock solution. Five hours after the final injection, the mice were euthanized, and brains were removed. We measured catecholamine metabolites affected by DBH via high-performance liquid chromatography with electrochemical detection, and assessed brain histopathology.

RESULTS

Compared to mock-treated controls, mo-br mice that received intraperitoneal L-DOPS showed significant increases in brain norepinephrine (p < 0.001) and its deaminated metabolite, dihydroxyphenylglycol (p < 0.05). The ratio of a non-beta-hydroxylated metabolite in the catecholamine biosynthetic pathway, dihydroxyphenylacetic acid, to the beta-hydroxylated metabolite, dihydroxyphenylglycol, improved equivalently to results obtained previously with brain-directed ATP7A gene therapy (p < 0.01). However, L-DOPS treatment did not arrest global brain pathology or improve somatic growth, as gene therapy had.

INTERPRETATION

We conclude that (1) L-DOPS crosses the blood-brain barrier in mo-br mice and corrects brain neurochemical abnormalities, (2) norepinephrine deficiency is not the cause of neurodegeneration in mo-br mice, and (3) L-DOPS treatment may ameliorate noradrenergic hypofunction in Menkes disease.

Heterogeneity of the tumorigenic phenotype expressed by Madin-Darby canine kidney cells

The mechanisms by which cells spontaneously immortalized in tissue culture develop the capacity to form tumors in vivo likely embody fundamental processes in neoplastic development. The evolution of Madin-Darby canine kidney (MDCK) cells from presumptively normal kidney cells to immortalized cells that become tumorigenic represents an example of neoplastic development in vitro. Studies of the mechanisms by which spontaneously immortalized cells develop the capacity to form tumors would benefit from quantitative in vivo assays. Most mechanistic correlations are evaluated by using single-dose tumor-induction experiments, which indicate only whether cells are or are not tumorigenic. Here we used quantitative tumorigenicity assays to measure dose-and time-dependent tumor development in nude mice of 3 lots of unmodified MDCK cells. The results revealed lot-to-lot variations in the tumorigenicity of MDCK cells, which were reflected by their tumor-inducing efficiency (threshold cell dose represented by mean tumor-producing dose; log(10) 50% endpoints of 5.2 for vial 1 and 4.4 for vial 2, and a tumor-producing dose of 5.8 for vial 3) and mean tumor latency (vial 1,6.6 wk; vial 2,2.9 wk; and vial 3,3.8 wk). These studies provide a reference for further characterization of the MDCK cell neoplastic phenotype and may be useful in delineating aspects of neoplastic development in vitro that determine tumor-forming capacity. Such data also are useful when considering MDCK cells as a reagent for vaccine manufacture.

Abstract 2417: A new mouse model for epithelial ear neoplasms based upon expression of mutant EGFRL858R/T790M

Epithelial neoplasms of the ear are rare and difficult to detect before the development of audiovestibular or facial nerve dysfunction. Complete resection is often difficult because of location and the late stage at diagnosis, so effective chemotherapy is required. No preclinical models exist for these tumors. During the generation of mice using CC10 or surfactant protein C (SP-C) promoters to drive expression of mutant EGFR (EGFRL858R/T790M) in lung tissues, we observed that no SP-C mice developed lung tumors, but approximately 30% of them developed head tilt and a circular gait by 25 wk. MRI scans showed bilateral ear tumors located in the tympanic cavity that partially invaded into temporal bone, which suggested the presence of middle ear tumors or endolymphatic sac tumors (ELSTs). Histology of the ear tumors showed well-differentiated adenocarcinomas with multiple papillary and microcystic structures. Immunohistochemical (IHC) analysis showed that the mutant EGFR was active and selectively expressed in the tumors, and that downstream components of EGFR signaling such as Akt, mTOR and ERK were activated. SP-C expression was also detected, suggesting that surfactant proteins are expressed in ear epithelium at specific times during tumor development. To determine if these tumors were addicted to EGFR signaling, EGFR-based therapies were tested in symptomatic mice. Consistent with the T790M mutation in EGFR conferring resistance to reversible EGFR tyrosine kinase inhibitors (TKI), erlotinib was ineffective. In contrast, the combination of an irreversible EGFR TKI (BIBW-2992) with an antibody against EGFR (cetuximab), or a chemically optimized analogue of BIBW-2992 (WZ4002) used alone, was highly effective. All mice treated with the combination or WZ4002 alone had normalization of gait and complete responses by MRI, suggesting that these tumors are dependent upon mutant EGFR. To assess the possible clinical relevance of this mouse model, 2 human middle ear adenocarcinomas and a human ELST were stained for active EGFR using IHC. 3/3 displayed increased EGFR activation. These studies describe a new mouse model for human epithelial ear tumors based on EGFR activation, and raise the possibility that EGFR-based therapies might have clinical efficacy in these rare neoplasms.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2417. doi:10.1158/1538-7445.AM2011-2417

Spontaneous Staphylococcus xylosus infection in mice deficient in NADPH oxidase and comparison with other laboratory mouse strains

Staphylococcus xylosus typically is described as a nonpathogenic common inhabitant of rodent skin. Reports of S. xylosus as a primary pathogen in human and veterinary medicine are scarce. Here we report 37 cases, affecting 12 strains of laboratory mice, of spontaneous infections in which S. xylosus was isolated and considered to be the primary pathogen contributing to the death or need for euthanasia of the animal. Infection with S. xylosus was the major cause of death or euthanasia in 3 strains of mice deficient in the production of phagocyte superoxide due to defects in NADPH oxidase. NADPH-oxidase-deficient mice (n = 21) were most susceptible to spontaneous S. xylosus infections. The infections were characterized by abscesses and granulomas in soft tissues, with bacterial migration to internal organs (primarily regional lymph nodes and lungs and, to a lesser degree, muscle, bone, and meninges). In contrast, 9 strains of phagocyte-superoxide-producing mice (n = 16) also had S. xylosus infections, but these were largely confined to eyelids, ocular conjunctiva, and skin and rarely involved other tissues or organs. Because exhaustive bacterial culture and isolation may not be performed routinely from mouse abscesses, S. xylosus infections may be underdiagnosed. S. xylosus should be considered in the differential diagnosis in laboratory mice with abscesses and other skin lesions. This report expands the range of mouse strains and tissues and organs susceptible to spontaneous S. xylosus infection and compares the pathology among various mice strains.

Comparison of carbon dioxide and argon euthanasia: effects on behavior, heart rate, and respiratory lesions in rats

In this study we compared rat (n = 16) responses to euthanasia with either gradual-fill CO(2) or rapid induction argon gas by evaluating the animals' heart rate via radiotelemetry, behavior, and vocalizations. We also evaluated the histologic effects of the gases. Rats were placed in an open test chamber 24 h before the start of the experiment. During baseline tests, rats were exposed to oxygen to evaluate the effects of the noise and movement of gas entering the chamber; 1 wk later, rats were euthanized by gas displacement with either 10%/min CO(2) or 50%/min argon gas. Rats tended to have higher heart rats and were more active during the baseline test, but these parameters were normal before the euthanasia experiment, suggesting that the rats had acclimated to the equipment. Heart rate, behavior, and ultrasonic vocalizations were recorded for 2 min after gas introduction in both groups. All rats appeared conscious throughout the test interval. The heart rates of rats exposed to argon did not change, whereas those of rats exposed to CO(2) declined significantly. Unlike those exposed to CO(2), rats euthanized with argon gas gasped and demonstrated seizure-like activity. There were no differences in the pulmonary lesions resulting from death by either gas. Our results suggest that argon as a sole euthanasia agent is aversive to rats. CO(2) using a 10%/min displacement may be less aversive than more rapid displacements. Future research investigating methods of euthanasia should allow sufficient time for the rats to acclimate to the test apparatus.

Antisense phosphorodiamidate morpholino oligomers targeted to an essential gene inhibit Burkholderia cepacia complex

BACKGROUND

Members of the Burkholderia cepacia complex (Bcc) cause considerable morbidity and mortality in patients with chronic granulomatous disease and cystic fibrosis. Many Bcc strains are antibiotic resistant, which requires the exploration of novel antimicrobial approaches, including antisense technologies such as phosphorodiamidate morpholino oligomers (PMOs).

METHODS

Peptide-conjugated PMOs (PPMOs) were developed to target acpP, which encodes an acyl carrier protein (AcpP) that is thought to be essential for growth. Their antimicrobial activities were tested against different strains of Bcc in vitro and in infection models.

RESULTS

PPMOs targeting acpP were bactericidal against clinical isolates of Bcc (>4 log reduction), whereas a PPMO with a scrambled base sequence (scrambled PPMO) had no effect on growth. Human neutrophils were infected with Burkholderia multivorans and treated with AcpP PPMO. AcpP PPMO augmented killing, compared with neutrophils alone and compared with neutrophils alone plus scrambled PPMO. Mice with chronic granulomatous disease that were infected with B. multivorans were treated with AcpP PPMO, scrambled PPMO, or water at 0, 3, and 6 h after infection. Compared with water-treated control mice, the AcpP PPMO-treated mice showed an approximately 80% reduction in the risk of dying by day 30 of the experiment and relatively little pathology.

CONCLUSION

AcpP PPMO is active against Bcc infections in vitro and in vivo.

Amelanotic melanoma in a New Zealand White Rabbit (Oryctolagus cuniculus)

A 3.5-year-old intact male double-transgenic New Zealand white rabbit (Oryctolagus cuniculus), apoA-I and LCAT (apolipoprotein and lecithin:cholesterol acyltransferase), was presented with a discrete, raised facial mass (0.5 x 1.0 x 1.0 cm). The mass was surgically excised, with reoccurrence to the same site 88 days later. A second surgical excision was performed, and the rabbit died 3 weeks later from respiratory distress. At necropsy, multiple varying-sized masses were observed in the ventral mandibular region and throughout the lungs, pleura, and diaphragm. On histopathology, the masses were composed of moderately anisocytotic and anisokaryotic polygonal to spindloid cells with moderate finely granular, lightly eosinophilic cytoplasm, having round to oval nuclei with one to several nucleoli and finely stippled chromatin. Mitotic figures were frequent. Lymphatic and venous invasion were noted with neoplastic cells metastasized to the submandibular lymph nodes, lungs, liver, and adventitial surface of the aorta. Fontana-Masson stain was negative for melanin, thereby necessitating immunohistochemistry and transmission electron microscopy. Positive staining with MART-1 (a melanocyte protein marker) combined with transmission electron microscopy revealing type II melanosomes confirmed the diagnosis of an amelanotic melanoma.

Safety of intracerebroventricular copper histidine in adult rats

Classical Menkes disease is an X-linked recessive neurodegenerative disorder caused by mutations in a P-type ATPase (ATP7A) that normally delivers copper to the developing central nervous system. Infants with large deletions, or other mutations in ATP7A that incapacitate copper transport to the brain, show poor clinical outcomes and subnormal brain copper despite early subcutaneous copper histidine (CuHis) injections. These findings suggest a need for direct central nervous system approaches in such patients. To begin to evaluate an aggressive but potentially useful new strategy for metabolic improvement of this disorder, we studied the acute and chronic effects of CuHis administered by intracerebroventricular (ICV) injection in healthy adult rats. Magnetic resonance imaging (MRI) after ICV CuHis showed diffuse T(1)-signal enhancement, indicating wide brain distribution of copper after ICV administration, and implying the utility of this paramagnetic metal as a MRI contrast agent. The maximum tolerated dose (MTD) of CuHis, defined as the highest dose that did not induce overt toxicity, growth retardation, or reduce lifespan, was 0.5mcg. Animals receiving multiple infusions of this MTD showed increased brain copper concentrations, but no significant differences in activity, behavior, and somatic growth, or brain histology compared to saline-injected controls. Based on estimates of the brain copper deficit in Menkes disease patients, CuHis doses 10-fold lower than the MTD found in this study may restore proper brain copper concentration. Our results suggest that ICV CuHis administration have potential as a novel treatment approach in Menkes disease infants with severe mutations. Future trials of direct CNS copper administration in mouse models of Menkes disease will be informative.

Demodex spp. in the hair follicles of rhesus macaques (Macaca mulatta)

The perineal or perineal and facial skin were evaluated on 53 rhesus macaques as part of a necropsy protocol. Microscopic evaluation of H & E stained skin sections revealed 19 animals positive for Demodex spp. Mites were seen within all portions of the hair follicles. Infestation varied from minimal to severe. Mites were found in macaques of all ages and in both sexes. Reaction to the mites ranged from no reaction, to minimal follicular epidermal hyperplasia to furunculosis. Immune status of the animal did not determine infestation but immune compromised macaques had more severe lesions. This is the first known report of Demodex spp. in rhesus macaques.