Prevalence and characterization of leukotoxin-producing Staphylococcus intermedius in Isolates from dogs and pigeons

Staphylococcus intermedius isolates from dogs (n = 44) and pigeons (n = 62) were categorized into 12 types by intergenic ribosomal DNA spacer polymorphism analysis. All isolates from pigeons were lukS positive and all isolates from dogs were lukS and lukF positive by dot blot analysis. The mean leukotoxicity titer for dog isolates was at least 129-fold higher than that for pigeon isolates.     

Developmental changes in concentrations and distributions of neurotrophins in the monkey cerebellar cortex

Neurotrophins are involved in the survival, differentiation, migration and neurite outgrowth of various neuronal populations. Neurotrophins and their receptors are widely expressed in the developing cerebellum of various experimental animals. To gain some insight into the possible roles played by these molecules in monkey cerebellum, we examined the protein levels of BDNF, NT-4/5 and NT-3 and distributions of those neurotrophins and TrkC, a high affinity receptor for NT-3, in the cerebellum of developing macaque monkeys using ELISAs and immunohistochemical methods. We found that the level of BDNF increased during development, while the level of NT-3 was higher during embryonic stages and decreased toward adulthood. The level of NT-4/5 increased from embryonic stages to infant stages and gradually declined with age. Among the three neurotrophins, BDNF immunoreactivity was found in all kinds of cerebellar neurons, including all inhibitory interneurons, throughout the postnatal periods examined, indicating that BDNF may be an essential factor for the maintenance of cerebellar neural functions. The Bergmann glial fibers and the internal part of the external granule cell layer were strongly NT-3 immunopositive at the early postnatal stages, and more weakly immunoreactive toward adulthood. In addition, we found that the premigratory precursors of the granule cells were TrkC immunopositive at early postnatal stages. These findings suggest that NT-3 in Bergmann glial fibers may be involved in the migration of the premigratory granule cells.     

Severe Neutropenia in Japanese Patients with X-Linked Agammaglobulinemia

X-linked agammaglobulinemia (XLA) is clinically characterized by recurrent bacterial infections during early infancy. Although it is not a phagocytic disorder, XLA is sometimes associated with neutropenia. We conducted a nation-wide survey to determine the frequency of neutropenia among Japanese XLA patients. Responses were received from 87 (86%) of 101 patients in which BTK mutations were previously identified, and of these, 16 (18%) had neutropenia. All episodes of neutropenia occurred before initiation of intravenous immunoglobulin (IVIG) replacement therapy. Two XLA patients died of multiple organ failure caused by severe neutropenia and Pseudomonas sepsis before initiation of IVIG replacement therapy. These results suggest that, in some cases, severe bacterial infections in XLA patients might be caused not only by antibody deficiencies but also by neutropenia.     

Clinical heterogeneity of neonatal intrahepatic cholestasis caused by citrin deficiency: case reports from 16 patients

A deficiency of citrin, which is encoded by the SLC25A13 gene, causes both adult-onset type II citrullinemia (CTLN2) and neonatal intrahepatic cholestasis (NICCD). We analyzed 16 patients with NICCD to clarify the clinical features of the disease. Severe intrahepatic cholestasis with fatty liver was the most common symptom, but the accompanying clinical features were variable, namely; suspected cases of neonatal hepatitis or biliary atresia, positive results from newborn screening, tyrosinemia, failure to thrive, hemolytic anemia, bleeding tendencies and ketotic hypoglycemia. Laboratory data showed elevated serum bile acid levels, hypoproteinemia, low levels of vitamin K-dependent coagulation factors, and hypergalactosemia. Hypercitrullinemia was detected in 11 out of 15 patients examined. Most of the patients were given a lactose-free and/or medium chain triglycerides-enriched formula and lipid-soluble vitamins. The prognosis of the 16 patients is going fairy well at present, but we should observe these patients carefully to see if they manifest any symptom of CTLN2 in the future.     

Case of postradiation osteosarcoma with a short latency period of 3 years

Osteosarcoma is one of the neoplasms that may occur following exposure to radiation. A case of osteosarcoma arising in the craniofacial bone with a short latency period of 3 years after radiotherapy for maxillary squamous cell carcinoma is described. A 64-year-old-man underwent right partial maxillectomy and chemoradiotherapy due to squamous cell carcinoma of his right maxillary sinus. Histologically, the tumor was composed of moderately differentiated squamous cell carcinoma with a component of spindle cell carcinoma. Three years later, osteosarcoma developed in the craniofacial bone within the irradiation field of the first tumor. Detailed histological examination demonstrated that there was no component of osteosarcoma in the first tumor or squamous cell carcinoma in the second tumor. Radiation-induced osteosarcoma usually occurs after a long latency period of more than 10 years after the radiotherapy. In this case, osteosarcoma was possibly a radiation-induced osteosarcoma with a short latency period of 3 years.     

Mitochondrial aspartate glutamate carrier (citrin) deficiency as the cause of adult-onset type II citrullinemia (CTLN2) and idiopathic neonatal hepatitis (NICCD)

 By using homozygosity mapping and positional cloning, we have shown that adult-onset type II citrullinemia (CTLN2) is caused by mutations of the SLC25A13 gene, which is localized on chromosome 7q21.3 and encodes a mitochondrial solute carrier protein named citrin. So far, we have reported nine mutations, most of which cause loss of citrin, and we have established several methods for DNA diagnosis. These methods have shown that more than 90% of the patients diagnosed as suffering from CTLN2 by enzymatic analysis carry SLC25A13 mutations in both alleles, indicating that CTLN2 is caused by citrin deficiency. Furthermore, by using the same DNA diagnosis methods, we discovered that 70 neonates or infants suffering from a particular type of neonatal hepatitis carry the same SLC25A13 mutations. Since the symptoms of the neonates are different from those of the more severe CTLN2 and usually ameliorate without special treatment, we designated the neonatal disease neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). We conclude that citrin deficiency causes NICCD in neonates and CTLN2 in adults through the additional effects of genetic or environmental modifiers. Since the function of citrin, together with that of an isoform, aralar, was found to be as a mitochondrial aspartate glutamate carrier, the various symptoms of NICCD and CTLN2 may be understood as caused by defective aspartate export from the mitochondria to the cytosol and defects in the malate aspartate shuttle. It is, however, still difficult to understand the cause of the hepatic deficiency of argininosuccinate synthetase protein in CTLN2. Received: March 20, 2002 / Accepted: March 28, 2002     

Significance of beta-catenin and pRB pathway components in malignant ovarian germ cell tumours: INK4A promoter CpG island methylation is associated with cell proliferation

To clarify the mechanisms underlying cell cycle promotion in malignant germ cell tumours of the ovary (MGCTOs), beta-catenin and components of the pRB pathway, cyclin D1 and p16, were analysed in relation to cell proliferation. Immunohistochemically, p16 protein was not expressed in a number of MGCTOs (9 of 42 tumours: 21.4%) and was associated with p16 gene (INK4A) promoter 5'-CpG islands methylation. Amplification of the cyclin D1 gene (CCND1) was detected in a small number of MGCTOs (5 of 42 tumours: 13.5%). Reduced expression of p16 due to promoter methylation correlated significantly with increased cell proliferation as evidenced by Ki-67 labelling index (p < 0.001) and mitotic index (p < 0.01). In some tumour types, nuclear localization of beta-catenin has been reported to be associated with beta-catenin gene (CTNNB1) mutation, cyclin D1 overexpression, and increased cell proliferation. Nuclear localization of beta-catenin, which was observed in MGCTOs other than dysgerminoma, was not associated with cyclin D1 expression and increased cell proliferation, but appeared to be related to tumour differentiation. Furthermore, CTNNB1 mutations were not detected in any of the MGCTOs examined. Our results suggest that reduced expression of p16 due to INK4A promoter methylation is one of the principal factors that promote cell proliferation in MGCTOs. Thus, p16 may be a novel target for gene therapies to treat MGCTOs.     

Melanocyte lysis by cytotoxic T lymphocytes recognizing the MART-1 melanoma antigen in HLA-A2 patients with Vogt Koyanagi Harada disease

The MART-1/Melan-A melanoma antigen recognized by the majorityof HLA-A2-restricted tumorinfiltrating lymphocytes is a selfantigen expressed on melanocytes and the retina. We have investigatedwhether Vogt–Koyanagi–Harada (VKH) disease and sympatheticophthalmia (SO), systemic inflammatory disorders affecting variousorgans containing melanocytes, are autoimmune diseases directedtoward the MART-1 antigen. In two of three patients with VKHdisease and one patient with SO, CD8⁺ T cell clones (TCC) fromintraocular fluid of HLA-A2⁺ patients lysed T2 cells when pulsedwith a HLA-A2-binding MART-1 peptide, but not a HLA-A2-bindingpMel-17 or tyrosinase peptide, in a HLA-A2-restricted manner.These CD8⁺ TCC lysed both melanocytes and melanoma cells ina HLA-A2-restricted manner. In addition, CD8⁺ TCC recognizinga HLA-A2-binding MART-1 peptide were also established from peripheralblood mononuclear cells of a patient with VKH disease. In contrast,either CD4⁺ TCC from these patients or CD8⁺ TCC from the intraocularfluid of HLA-A2⁺ patients with uveitis associated with Behcet'sdisease or HTLV-I uveitis did not show this cytotoxicity. Theresults demonstrate that the MART-1 peptide-specific cytotoxicT lymphocytes lyse melanocytes in the eye of patients with VKHdisease or SO, suggesting that these diseases are autoimmunediseases directed toward the MART-1 antigen in HLA-A2⁺ patients.     

Spontaneous wheel running attenuates cardiovascular responses to stress in rats

We investigated the effect of chronic, 10-week spontaneous wheel running (SWR) exercise on stress-induced cardiovascular responses in free-moving male rats, using a biotelemetry system. During cage-switch stress or immobilization stress, blood pressure and heart rate were significantly increased in both the SWR (P<0.001 for each stress) and control groups (P<0.001 for each stress). However the blood pressure response was attenuated significantly in the SWR group (P<0.001) during cage-switch stress, and the blood pressure and heart rate responses were attenuated significantly in the SWR group (P<0.0001 and 0.01, respectively) during immobilization stress. The plasma norepinephrine (NE) response induced by immobilization stress tended to be attenuated in the SWR group, but the groups showed no significant differences in the plasma NE and epinephrine (E) responses to both stresses. These results suggest that daily SWR in rats has beneficial effects in suppressing excessive blood pressure and heart rate responses induced by two different types of stress. The mechanisms responsible for the greater resistance to these stresses in the SWR rats should be investigated further.     

DNA analysis of two patients with a non-fluorescent y chromosome

Summary Results of DNA study on two patients of gonadal dysgenesis with a 45,X/46,X,Ynf (non-fluorescent Y chromosome) karyotype are described. In one patient who developed gonadoblastoma, all 12 loci on the non-fluorescent part of Yq were detected. Another patient did not have gonadoblastoma at 20 years, and only the proximal 6 loci out of 12 were detected.