The root meristem is shaped by brassinosteroid control of cell geometry.

Growth extent and direction determine cell and whole-organ architecture. How they are spatio-temporally modulated to control size and shape is not well known. Here we tackled this question by studying the effect of brassinosteroid (BR) signalling on the structure of the root meristem. Quantification of the three-dimensional geometry of thousands of individual meristematic cells across different tissue types showed that the modulation of BR signalling yields distinct changes in growth rate and anisotropy, which affects the time that cells spend in the meristem and has a strong impact on the final root form. By contrast, the hormone effect on cell volume was minor, establishing cell volume as invariant to the effect of BR. Thus, BR has the highest effect on cell shape and growth anisotropy, regulating the overall longitudinal and radial growth of the meristem, while maintaining a coherent distribution of cell sizes. Moving from single-cell quantification to the whole organ, we developed a computational model of radial growth. The simulation demonstrates how differential BR-regulated growth between the inner and outer tissues shapes the meristem and thus explains the non-intuitive outcomes of tissue-specific perturbation of BR signalling. The combined experimental data and simulation suggest that the inner and outer tissues have distinct but coordinated roles in growth regulation.

Approaches to Investigating Complex Genetic Traits in a Large-Scale Inbred Mouse Aging Study.

Inbred mice are a unique model system for studying aging because of the genetic homogeneity within inbred strains, the short life span of mice relative to humans, and the rich array of analytic tools that are available. A large-scale aging study was conducted on 28 inbred strains representing great genetic diversity to determine, via histopathology, the type and diversity of spontaneous diseases that aging mice develop. A total of 20 885 different diagnoses were made, with an average of 12 diagnoses per mouse in the study. Eighteen inbred strains have had their genomes sequenced, and many others have been partially sequenced to provide large repositories of data on genetic variation among the strains. This vast amount of genomic information can be utilized in genome-wide association studies to find candidate genes that are involved in the pathogenesis of spontaneous diseases. As an illustration, this article presents a genome-wide association study of the genetic associations of age-related intestinal amyloidosis, which implicated 3 candidate genes: translocating chain-associated membrane protein 1 (Tram1); splicing factor 3b, subunit 5 (Sf3b5); and syntaxin 11 (Stx11). Representative photomicrographs are available on the Mouse Tumor Biology Database and Pathbase to serve as a reference when evaluating inbred mice used in other genetic or experimental studies to rule out strain background lesions. Many of the age-related mouse diseases are similar, if not identical, to human diseases; therefore, the genetic discoveries have direct translational benefit.

Extremity compartment syndrome and fasciotomy: a literature review.

Trauma surgeons frequently encounter injured limbs at risk for compartment syndrome. This article reviews data regarding the pathophysiology of compartment syndrome, factors in measuring compartment pressures, thresholds for performing fasciotomies, and outcomes from the development of compartment syndromes and performing fasciotomies.

Social deprivation and statin prescribing: a cross-sectional analysis using data from the new UK general practitioner 'Quality and Outcomes Framework'.

We aimed to study the relationship between the prescribing of lipid-lowering medication, social deprivation and other general practice characteristics. We conducted a cross-sectional survey of all general practices in England, 2004-05. For each practice, the following variables were obtained: standardized cost and volume data for lipid-lowering medication, descriptors of general practices, Index of Multiple Deprivation, 2004, ethnicity data from the 2001 Census and Quality and Outcomes Framework data. A regression model was constructed which explained 34.5% of the variation in statin prescribing by general practitioners. The most powerful predictors were higher social deprivation, higher prevalence of coronary heart disease and achievement of cholesterol targets for diabetics. Negative regression coefficients were demonstrated for the proportion of elderly patients in the practice and, to a lesser extent, for the proportion of south Asian and Afro-Caribbean patients. In conclusion, contrary to previous local studies, we found that statin prescribing was higher in more deprived communities, even after adjustment for increased disease prevalence and practice variables associated with deprivation. Statin prescribing was also independently associated with success at achieving cholesterol targets in established disease (secondary prevention). However, our findings suggest under-prescribing of statins to the elderly and possibly also to ethnic minorities.

Alms1-disrupted mice recapitulate human Alström syndrome.

Mutations in the human ALMS1 gene cause Alström syndrome (AS), a progressive disease characterized by neurosensory deficits and by metabolic defects including childhood obesity, hyperinsulinemia and Type 2 diabetes. Other features that are more variable in expressivity include dilated cardiomyopathy, hypertriglyceridemia, hypercholesterolemia, scoliosis, developmental delay and pulmonary and urological dysfunctions. ALMS1 encodes a ubiquitously expressed protein of unknown function. To obtain an animal model in which the etiology of the observed pathologies could be further studied, we generated a mouse model using an Alms1 gene-trapped ES cell line. Alms1-/- mice develop features similar to patients with AS, including obesity, hypogonadism, hyperinsulinemia, retinal dysfunction and late-onset hearing loss. Insulin resistance and increased body weight are apparent between 8 and 12 weeks of age, with hyperglycemia manifesting at approximately 16 weeks of age. In addition, Alms1-/- mice have normal hearing until 8 months of age, after which they display abnormal auditory brainstem responses. Diminished cone ERG b-wave response is observed early, followed by the degeneration of photoreceptor cells. Electron microscopy revealed accumulation of intracellular vesicles in the inner segments of photoreceptors, whereas immunohistochemical analysis showed mislocalization of rhodopsin to the outer nuclear layer. These findings suggest that ALMS1 has a role in intracellular trafficking.

Cavitary endoscopy in trauma: 2001.

Laparoscopy and thoracoscopy have been used in the evaluation of injured patients for over 30 years. Despite this long history, indications for use of these techniques remains controversial. The widespread availability of videoscopic equipment which followed the introduction of laparoscopic cholecystectomy increased interest and utilization of minimally invasive techniques in evaluation of trauma patients. Laparoscopy has been most beneficial in the evaluation of hemodynamically stable victims of stabbings and gunshots. This technique has primarily been used to detect peritoneal penetration in tangential wounds of the abdominal wall and for evaluation of the diaphragm in patients with thoracoabdominal wounds. Laparoscopic evaluation in blunt trauma patients is of unproven utility, but has been used in the assessment of patients with documented solid organ injury and in the evaluation of patients with suspected hollow viscus injury. Small subsets of patients are candidates for therapeutic laparoscopic interventions, i.e., suture repair of diaphragmatic lacerations. Thoracoscopy or videoassisted thoracic surgery (VATS) is useful for evaluation of the diaphragm, early evacuation of clotted hemothorax, and assessment of ongoing bleeding.

Haploinsufficient Bmp4 ocular phenotypes include anterior segment dysgenesis with elevated intraocular pressure.

BACKGROUND: Glaucoma is a blinding disease usually associated with high intraocular pressure (IOP). In some families, abnormal anterior segment development contributes to glaucoma. The genes causing anterior segment dysgenesis and glaucoma in most of these families are not identified and the affected developmental processes are poorly understood. Bone morphogenetic proteins (BMPs) participate in various developmental processes. We tested the importance of Bmp4 gene dosage for ocular development and developmental glaucoma. RESULTS: Bmp4+/- mice have anterior segment abnormalities including malformed, absent or blocked trabecular meshwork and Schlemm's canal drainage structures. Mice with severe drainage structure abnormalities, over 80% or more of their angle's extent, have elevated IOP. The penetrance and severity of abnormalities is strongly influenced by genetic background, being most severe on the C57BL/6J background and absent on some other backgrounds. On the C57BL/6J background there is also persistence of the hyaloid vasculature, diminished numbers of inner retinal cells, and absence of the optic nerve. CONCLUSIONS: We demonstrate that heterozygous deficiency of BMP4 results in anterior segment dysgenesis and elevated IOP. The abnormalities are similar to those in human patients with developmental glaucoma. Thus, BMP4 is a strong candidate to contribute to Axenfeld-Rieger anomaly and other developmental conditions associated with human glaucoma. BMP4 also participates in posterior segment development and wild-type levels are usually critical for optic nerve development on the C57BL/6J background. Bmp4+/- mice are useful for studying various components of ocular development, and may allow identification of strain specific modifiers affecting a variety of ocular phenotypes.

Targeted Disruption of the Myocilin Gene (Myoc) Suggests that Human Glaucoma-Causing Mutations Are Gain of Function.

Glaucoma is a heterogeneous eye disease and a major cause of blindness worldwide. Recently, primary open angle glaucoma (POAG)-associated mutations have been found in the trabecular meshwork inducible glucocorticoid response gene (TIGR), also known as the myocilin gene (MYOC), at the GLC1A locus on chromosome 1q21-q31. These mutations occurred in a subset of patients with juvenile- and adult-onset POAG and exhibited autosomal dominant inheritance. Ocular expression and its involvement in POAG suggest that TIGR/MYOC may have a role(s) in regulating intraocular pressure (IOP). Here, we report the generation and analysis of mice heterozygous and homozygous for a targeted null mutation in Myoc. Our study shows that Myoc mutant mice are both viable and fertile. Our in vivo findings further demonstrate that Myoc is not required for normal IOP or normal ocular morphology. The lack of a discernable phenotype in both Myoc-heterozygous and Myoc-null mice suggests that haploinsufficiency is not a critical mechanism for POAG in individuals with mutations in MYOC. Instead, disease-causing mutations in humans likely act by gain of function.

Telemedicine and trauma care.

Advances in technology have made it possible for telemedicine to be used in multiple areas of medicine, including trauma care. Teleradiology and teleconsultation are becoming standard operating procedure for many rural facilities. Future uses of telemedicine include teleproctoring and telepresence surgery. The medicolegal and financial impact of telemedicine remains to be determined. The potential influence of telemedicine in the care of future trauma patients will likely be important and may alter patterns of referral, consultation, and treatment.

Intraocular pressure in genetically distinct mice: an update and strain survey.

BACKGROUND: Little is known about genetic factors affecting intraocular pressure (IOP) in mice and other mammals. The purpose of this study was to determine the IOPs of genetically distinct mouse strains, assess the effects of factors such as age, sex and time of day on IOP in specific strain backgrounds, and to assess the effects of specific candidate gene mutations on IOP. RESULTS: Based on over 30 studied mouse strains, average IOP ranges from approximately 10 to 20 mmHg. Gender does not typically affect IOP and aging results in an IOP decrease in some strains. Most tested strains exhibit a diurnal rhythm with IOP being the highest during the dark period of the day. Homozygosity for a null allele of the carbonic anhydrase II gene (Car2n) does not alter IOP while homozygosity for a mutation in the leptin receptor gene (Leprdb) that causes obesity and diabetes results in increased IOP. Albino C57BL/6J mice homozygous for a tyrosinase mutation (Tyrc-2J) have higher IOPs than their pigmented counterparts. CONCLUSIONS: Genetically distinct mouse strains housed in the same environment have a broad range of IOPs. These IOP differences are likely due to interstrain genetic differences that create a powerful resource for studying the regulation of IOP. Age, time of day, obesity and diabetes have effects on mouse IOP similar to those in humans and other species. Mutations in two of the assessed candidate genes (Lepr and Tyr) result in increased IOP. These studies demonstrate that mice are a practical and powerful experimental system to study the genetics of IOP regulation and disease processes that raise IOP to harmful levels.

IL-8 production in human lung fibroblasts and epithelial cells activated by the Pseudomonas autoinducer N-3-oxododecanoyl homoserine lactone is transcriptionally regulated by NF-kappa B and activator protein-2.

The destructive pulmonary inflammation associated with Pseudomonas aeruginosa colonization is caused, in part, by the production of the chemokine IL-8, which recruits neutrophils into the lung. The Pseudomonas autoinducer, N-3-oxododecanoyl homoserine lactone (3-O-C12-HSL), is a small lipid-soluble molecule that is essential in the regulation of many P. aeruginosa virulence factors, but little is known about how it affects eukaryotic cells. In this report we demonstrate that 3-O-C12-HSL is a potent stimulator of both IL-8 mRNA and protein from human fibroblasts and epithelial cells in vitro. The IL-8 produced from these 3-O-C12-HSL-stimulated cells was found to be functionally active by inducing the chemotaxis of neutrophils. To determine a mechanism for this IL-8 induction, deletion constructs of the IL-8 promoter were examined. It was found that the DNA region between nucleotides -1481 and -546 and the transcription factor NF-kappaB were essential for the maximal induction of IL-8 by 3-O-C12-HSL. This was confirmed by EMSAs, where 3-O-C12-HSL induced a shift with both AP-2 and NF-kappaB consensus DNA. The activation of NF-kappaB and subsequent production of IL-8 were found to be regulated by a mitogen-activated protein kinase pathway. These findings support the concept that the severe lung damage that accompanies P. aeruginosa infections is caused by an exuberant neutrophil response stimulated by 3-O-C12-HSL-induced IL-8. Understanding the mechanisms of 3-O-C12-HSL activation of lung structural cells may provide a means to help control lung damage during infections with P. aeruginosa.

The mouse anterior chamber angle and trabecular meshwork develop without cell death.

BACKGROUND: The iridocorneal angle forms in the mammalian eye from undifferentiated mesenchyme between the root of the iris and cornea. A major component is the trabecular meshwork, consisting of extracellular matrix organized into a network of beams, covered in trabecular endothelial cells. Between the beams, channels lead to Schlemm's canal for the drainage of aqueous humor from the eye into the blood stream. Abnormal development of the iridocorneal angle that interferes with ocular fluid drainage can lead to glaucoma in humans. Little is known about the precise mechanisms underlying angle development. There are two main hypotheses. The first proposes that morphogenesis involves mainly cell differentiation, matrix deposition and assembly of the originally continuous mesenchymal mass into beams, channels and Schlemm's canal. The second, based primarily on rat studies, proposes that cell death and macrophages play an important role in forming channels and beams. Mice provide a potentially useful model to understand the origin and development of angle structures and how defective development leads to glaucoma. Few studies have assessed the normal structure and development of the mouse angle. We used light and electron microscopy and a cell death assay to define the sequence of events underlying formation of the angle structures in mice. RESULTS: The mouse angle structures and developmental sequence are similar to those in humans. Cell death was not detectable during the period of trabecular channel and beam formation. CONCLUSIONS: These results support morphogenic mechanisms involving organization of cellular and extracellular matrix components without cell death or atrophy.

What is normal intra-abdominal pressure?

The causes and effects of increased intra-abdominal pressure and abdominal compartment syndrome have been well documented. However, there have been no large series to determine normal intra-abdominal pressure in hospitalized patients. The purpose of this study was to determine normal intra-abdominal pressure in randomly selected hospitalized patients and to identify factors that predict variation in normal intra-abdominal pressure. A total of 77 patients were prospectively enrolled between September 1998 and July 1999. Data obtained included patient demographics (i.e., age, gender, height, weight, and body mass index), reason for hospitalization and bladder catheterization, previous and current surgical status, comorbidities, and intra-abdominal pressures. Intra-abdominal pressure readings were obtained through an indwelling transurethral bladder (Foley) catheter. Data were analyzed by analysis of variance and multiple regression analysis. There were 36 females and 41 males with a mean age of 67.7 years. Average weight, height, and body mass index were 79.6 kg, 1.70 m, and 27.6 kg/m2, respectively. Mean intraabdominal pressure was 6.5 mm Hg (range 0.2-16.2 mm Hg). Body mass index was positively related to intra-abdominal pressure (P < 0.0004). Gender, age, and medical and surgical histories did not significantly affect intra-abdominal pressure. However, using multiple regression analysis, a relationship between intra-abdominal pressure, body mass index, and abdominal surgery was discovered. Intra-abdominal pressure is related to a patient's body mass index and influenced by recent abdominal surgery. Thus, the normal intra-abdominal pressure can be estimated in hospitalized patients by using the derived equation. Knowledge of the expected intra-abdominal pressure can then by used in recognizing when an abnormally high intra-abdominal pressure or abdominal compartment syndrome exists.

Characterization of Corn1 mice: Alteration of epithelial and stromal cell gene expression.

PURPOSE: Corn1 is an autosomal recessive mutation characterized by corneal epithelial hyperplasia and stromal neovascularization. The aim of the present study is to examine the expression patterns of specific epithelial and stromal proteins in corn/corn1 mutant mice. METHODS: Immunohistochemistry with antibodies directed against keratins 1, 4, 5, 12, and 14 as well as loricrin, filaggrin, and involucrin were performed in corn1/corn1 and wild type, A.By/SnJ strain, mice at 4 weeks of age. Western blot hybridization was performed to confirm the presence of involucrin in corneas. In situ and northern blot hybridization were used to evaluate the expression of keratin 12, lumican, and keratocan in these mice. RESULTS: In corn1/corn1 mice, focal areas of corneal epithelial hyperplasia alternate with epithelium with normal appearance. Both regions of normal and hyperplastic corneal epithelium were labeled by anti-keratin 12 antibodies through all corneal epithelial layers. The anti-keratin 14 antibody only labeled the basal cell layer in normal epithelial areas, whereas it labeled both basal and suprabasal cell layers in hyperplastic areas. In wild type mice, anti-keratin 12 antibodies labeled all corneal epithelial layers, whereas anti-keratin 14 labeled the basal corneal epithelial cells only. Positive staining by anti-involucrin antibody was demonstrated in the basal corneal epithelial layer of wild type mice and normal areas of corn1/corn1 mice. Similarly, as observed with anti-keratin 14 antibody, the anti-involucrin antibody labeled both basal and suprabasal cell layers of hyperplastic corneal epithelium of corn1/corn1 mice. Antibodies against keratin 1, keratin 4, loricrin, and fillagrin did not label the corneas of wild type mice or corn1/corn1 mice. Northern hybridization indicated that the expressions of keratocan and lumican mRNA levels were up regulated in corn1/corn1 mice, but keratin 12 mRNA remained similar to that of the wild type mice. In situ hybridization revealed that the lumican mRNA was detected in epithelial and stromal cells of corn1/corn1 mice, whereas keratocan mRNA was only detected in stromal cells. CONCLUSIONS: Hyperproliferative epithelial cells of corn1/corn1 mice have increased levels of expression of keratin 14 and involucrin, but do not exhibit the phenotypical characteristics of cornification. These observations indicate that factors associated with the phenotypes of corn1/corn1 mice do not alter the cornea-type epithelial differentiation of keratin 12 expression, but cause aberrant expression of lumican by corneal epithelial cells.

Genetic modification of glaucoma associated phenotypes between AKXD-28/Ty and DBA/2J mice.

BACKGROUND: Glaucoma is a common disease but its molecular etiology is poorly understood. It involves retinal ganglion cell death and optic nerve damage that is often associated with elevated intraocular pressure. Identifying genes that modify glaucoma associated phenotypes is likely to provide insights to mechanisms of glaucoma. We previously reported glaucoma in DBA/2J mice caused by recessive alleles at two loci, isa and ipd, that cause iris stromal atrophy and iris pigment dispersion, respectively. A approach for identifying modifier genes is to study the effects of specific mutations in different mouse strains. When the phenotypic effect of a mutation is modified upon its introduction into a new strain, crosses between the parental strains can be used to identify modifier genes. The purpose of this study was to determine if the effects of the DBA/2J derived isa and ipd loci are modified in strain AKXD-28/Ty. RESULTS: AKXD-28/Ty mice develop glaucoma characterized by intraocular pressure elevation, retinal ganglion loss, and optic nerve excavation. In AKXD-28/Ty, isa causes an iris stromal atrophy phenotype as in DBA/2J. However, the iris pigment dispersion phenotype associated with ipd in DBA/2J does not occur in AKXD-28/Ty. Additionally, a greater severity and speed of retinal and optic nerve damage following intraocular pressure elevation in AKXD-28/Ty compared to DBA/2J mice suggests that AKXD-28/Ty is more susceptible to pressure-induced cell death. CONCLUSIONS: The consequences of the ipd and isa mutations are modified in the AKXD-28/Ty background. These strains provide a resource for the identification of modifier genes that modulate pigment dispersion and susceptibility to pressure-induced cell death.

Mice deficient in methylenetetrahydrofolate reductase exhibit hyperhomocysteinemia and decreased methylation capacity, with neuropathology and aortic lipid deposition.

Hyperhomocysteinemia, a risk factor for cardiovascular disease, is caused by nutritional and/or genetic disruptions in homocysteine metabolism. The most common genetic cause of hyperhomocysteinemia is the 677C-->T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene. This variant, with mild enzymatic deficiency, is associated with an increased risk for neural tube defects and pregnancy complications and with a decreased risk for colon cancer and leukemia. Although many studies have reported that this variant is also a risk factor for vascular disease, this area of investigation is still controversial. Severe MTHFR deficiency results in homocystinuria, an inborn error of metabolism with neurological and vascular complications. To investigate the in vivo pathogenetic mechanisms of MTHFR deficiency, we generated mice with a knockout of MTHFR: Plasma total homocysteine levels in heterozygous and homozygous knockout mice are 1.6- and 10-fold higher than those in wild-type littermates, respectively. Both heterozygous and homozygous knockouts have either significantly decreased S-adenosylmethionine levels or significantly increased S-adenosylhomocysteine levels, or both, with global DNA hypomethylation. The heterozygous knockout mice appear normal, whereas the homozygotes are smaller and show developmental retardation with cerebellar pathology. Abnormal lipid deposition in the proximal portion of the aorta was observed in older heterozygotes and homozygotes, alluding to an atherogenic effect of hyperhomocysteinemia in these mice.

Mouse models for the Wolf-Hirschhorn deletion syndrome.

Wolf-Hirschhorn syndrome (WHS) is a deletion syndrome caused by segmental haploidy of chromosome 4p16.3. Its hallmark features include a 'Greek warrior helmet' facial appearance, mental retardation, various midline defects and seizures. The WHS critical region (WHSCR) lies between the Huntington's disease gene, HD, and FGFR3. In mice, the homologs of these genes map to chromosome 5 in a region of conserved synteny with human 4p16.3. To derive mouse models of WHS and map genes responsible for subphenotypes of the syndrome, five mouse lines bearing radiation-induced deletions spanning the WHSCR syntenic region were generated and characterized. Similar to WHS patients, these animals were growth-retarded, were susceptible to seizures and showed midline (palate closure, tail kinks), craniofacial and ocular anomalies (colobomas, corneal opacities). Other phenotypes included cerebellar hypoplasia and a shortened cerebral cortex. Expression of WHS-like traits was variable and influenced by strain background and deletion size. These mice represent the first animal models for WHS. This collection of nested chromosomal deletions will be useful for mapping and identifying loci responsible for the various subphenotypes of WHS, and provides a paradigm for the dissection of other deletion syndromes using the mouse.

Splenic clearance mechanisms of rehydrated, lyophilized platelets.

A variety of platelet substitutes (e.g., rehydrated, lyophilized (RL) platelets, thromboerythrocytes, plateletsomes, infusible platelet membranes, synthocytes, fibrinogen-coated microcapules) are potentially useful as hemostatic agents in transfusion medicine. However, as "foreign" particles, platelet substitutes interact to varying extents with elements of the reticulo-endothelial system for clearance, reducing hemostatic efficacy. Experiments were performed to better understand the interaction of RL platelets with elements of the innate and acquired immune systems. The infusion of heterologous RL platelets into rats resulted in rapid clearance from the free circulation with half-life values of minutes. The clearance of RL platelets was inhibited when macrophages were rendered apoptotic with gadolinium. Transmission EM analysis of splenic tissue after infusion of lyophilized cells, as well as in vitro mixing studies with splenic macrophages and RL platelets, indicated that macrophage-mediated phagocytosis mechanisms were operant in RL platelet clearance by the reticulo-endothelial system. Studies with IV IgG, as a competitive inhibitor of the macrophage Fc receptor, provides evidence that RL platelet destruction is in part mediated by platelet surface bound IgG. This hypothesis was further supported by the finding that RL platelets react with IgG class antibodies that are pre-existing in naïve animals. These studies provide a rational basis for prolonging the circulation time of RL platelets and other platelet substitutes.

Defects in the cappuccino (cno) gene on mouse chromosome 5 and human 4p cause Hermansky-Pudlak syndrome by an AP-3-independent mechanism.

Defects in a triad of organelles (melanosomes, platelet granules, and lysosomes) result in albinism, prolonged bleeding, and lysosome abnormalities in Hermansky-Pudlak syndrome (HPS). Defects in HPS1, a protein of unknown function, and in components of the AP-3 complex cause some, but not all, cases of HPS in humans. There have been 15 inherited models of HPS described in the mouse, underscoring its marked genetic heterogeneity. Here we characterize a new spontaneous mutation in the mouse, cappuccino (cno), that maps to mouse chromosome 5 in a region conserved with human 4p15-p16. Melanosomes of cno/cno mice are immature and dramatically decreased in number in the eye and skin, resulting in severe oculocutaneous albinism. Platelet dense body contents (adenosine triphosphate, serotonin) are markedly deficient, leading to defective aggregation and prolonged bleeding. Lysosomal enzyme concentrations are significantly elevated in the kidney and liver. Genetic, immunofluorescence microscopy, and lysosomal protein trafficking studies indicate that the AP-3 complex is intact in cno/cno mice. It was concluded that the cappuccino gene encodes a product involved in an AP-3-independent mechanism critical to the biogenesis of lysosome-related organelles. (Blood. 2000;96:4227-4235)