Biotin deficiency in amino acid formula nutrition for an infant with milk protein allergy]

We reported a 4-month-old girl with biotin deficiency caused by amino acid formula. Two weeks after birth, she was diagnosed as having a milk protein allergy. After switching to amino acid formula from usual formula, her symptoms and laboratory findings became normal. About three weeks after the beginning of amino acid formula, she developed intractable skin erosions around the eyes, mouth, neck, and anogenital area. By measuring concentrations of some trace elements, she was diagnosed as having a biotin deficit, because of the organic aciduria and undetectable serum biotin concentration. Her serum biotinidase level was normal. Upon administration of oral biotin supplementation, all her symptoms and laboratory findings were dramatically improved. Since amino acid formula contains very few biotin, we should pay attention to biotin deficiency when infants receiving amino acid formula.     

Epstein-Barr virus-associated post-transplant primary smooth muscle tumor of the liver: Report of an autopsy case

Epstein-Barr (EB) virus-associated primary smooth muscle tumors have been reported in immunosuppressed young patients with acquired immunodeficiency syndrome (AIDS) and young people who have undergone liver transplantation. An autopsy case of EB virus-associated smooth muscle cell tumor in a 21 year old female who received immunosuppres-sive therapy following renal transplantation Is repotted. Multiple tumor nodules were present in the liver, but no primary lesion was found in any other organ. Histologically, the nodules were composed of spindle cells, positive for α-smooth muscle action, which were arranged in fascicles and closely associated with vascular channels, thereby suggesting a vascular smooth muscle cell origin. EB virus infection of the tumor cells was clearly demonstrated by in situ hybridization with an EB virus-encoded RNA 1 (EBER-1) probe. The present case illustrates that EB virus infection may play some role in the development of smooth muscle tumors not only in immunocompromised young patients with liver allo-grafts, but also in those with renal allografts.     

Primary osteosarcoma of the uterine corpus: case report and review of the literature

A rare case of rapidly growing osteosarcoma that developed in the uterine corpus of a 62-year-old woman is presented. The tumor occupied almost the entire pelvic cavity and extended into the abdominal cavity, with marked involvement of the intestines. Histopathologically, the tumor was composed of an osteoblastic component, accompanied by conspicuous bone formation, and a fibroblastic component. The tumor cells were positive for vimentin and osteocalcin, as well as desmin, alpha-smooth muscle actin and muscle-specific actin, but negative for h-caldesmon. The results indicated myofibroblastic differentiation in a part of the tumor. A review of 14 reported cases and our case of uterine osteosarcoma revealed that this tumor has a biologically aggressive nature, although its histopathological and immunohistochemical features are similar to those of osteosarcomas in soft tissue and bone. As the prognosis of patients with this tumor is poor, it is of importance to differentiate this tumor from other types of tumors arising from the uterine corpus.     

Evaluation of a new reflectance pulse oximeter for clinical applications

The design of a noninvasive reflectance pulse oximeter that uses the same principle of transmittance pulse oximeter and analyses the oxygen saturation of arterial blood was described. Four sets of red and infra-red LEDs were used as light sources. The respective reflectance photoelectric outputs were used to make an internal calibration curve of the instrument relative to the arterial oxygen saturation values measured with a Co-Oximeter (OSM-3) in five healthy nonsmoking subjects during steady-state hypoxaemia. The accuracy of the present instrument was studied in six patients with respiratory failure. From 22 samples, a good correlation coefficient (0.98) with a standard deviation of 1.42 was obtained in the range between 73 and 100 per cent between the arterial oxygen saturation measured with the present instrument and that with the Co-Oximeter. The result strongly suggests the usefulness of this oximeter in monitoring patients with hypoxaemia.     

Short-term desensitization of muscarinic K+ channel current in isolated atrial myocytes and possible role of GTP-binding proteins

The short-term desensitization of the acetylcholine (ACh)-induced K⁺ channel current was examined in single atrial cells of guinea-pig heart. The tight-seal whole cell voltage clamp technique was used. The solution in the pipettes contained GTP or guanosine-5-O-(3-thiotriphosphate) (GTP-S, a non-hydrolyzable GTP analogue). In GTP-loaded cells, ACh evoked a specific K⁺ channel current via GTP-binding proteins (G) in a dose-dependent manner. The K⁺ current showed agonist-dependent desensitization similar to those reported in other cardiac tissues (Nilius 1983; Carmeliet and Mubagwa 1986). The cellular response to ACh was also desensitized by activation of P1-purinergic receptors with adenosine (Ado). In GTP-S-loaded cells, the K⁺ current was gradually induced even in the absence of agonists, probably due to direct activation of G proteins by GTP-S. In the early phase of the spontaneous current increase, ACh evoked a large current transiently. As the GTP-S-induced activation of the current progressed, the magnitude of the ACh-evoked current transient became smaller and finally negligible. Similar results were obtained when Ado was used as an agonist instead of ACh to induce the K⁺ current. Therefore, it is indicated that the agonistreceptor interaction may not be essential for the desensitization of ACh-induced K⁺ current in atrial myocytes.     

FAMILIAL AMYLOID POLYNEUROPATHY WITH MARKED HYPERTROPHY OF THE PERIPHERAL NERVES

Autopsy findings in a 40-year-old male with heredofamilial amyloidosis and polyneuropathy are reported. He had been suffering from progressive autonomic as well as sensorimotor dysfunctions. Prominent amyloid deposit was found in the kidney, heart, thyroid, and testis, and less in the interstitium and small vessels of almost all organs. The peripheral nerves, some showing prominent hypertrophy, were most severely involved by amyloid deposit in a form of stellate mass, which ultrastructurally consisted of radially arranged amyloid filaments. In the hypertrophied nerves and ganglia, in addition to amyloid, massive accumulation of acid mucopolysaccharide (AMPS) was seen filling up the interstitial space, which was the cause of hypertrophy. Ultrastructurally, AMPS was seen as finely granular substance. An extracted amyloid from the kidney showed 8 nm filament on negative staining and was estimated of having a molecular weight of 14,000.     

Determination of a splice acceptor site of pX gene in HTLV-I infected cells

The splice acceptor site of pX gene of HTLV-I has been determined to be at base position 7301 using S1 nuclease protection analysis. This splice acceptor site is used in all HTLV-I immortalized T-cell clones studied despite variation in the abundance levels of pX mRNA. Our results confirmed the proposal by Haseltine et al. (W. A. Haseltine, J. Sodroski, R. Patarca, D. Briggs, D. Perkins, and F. Wong-Staal, Science (Washington, D. C. 225, 421-424 (1984); K. Shimotono, W. Wachsman, Y. Takahashi, D. W. Golde, M. Miwa, T. Sigimura, and I. S. Y. Chen, Proc. Natl. Acad. Sci. USA 81, 6657-6661 (1984)) that a pX protein with a molecular weight of at least 38,000 could be synthesized. Generation of a 2.0-kb pX mRNA may involve a double-splicing event.     

A common Ile796Val polymorphism of the human SREBP cleavage-activating protein (SCAP) gene

We identified a new common amino acid polymorphism of isoleucine/valine at codon 796 in exon 16 of the gene for human sterol regulatory element binding protein (SREBP) cleavage-activating protein (SCAP), a central regulator of lipid synthesis and metabolism in animal cells. It can be detected as an MslI restriction fragment length polymorphism. The allelic frequencies were: isoleucine (A) allele, 0.57 and valine (G) allele, 0.43. This polymorphism may be useful for genetic studies of disorders affecting intracellular lipid metabolism and hyperlipidemia. Received: August 17, 1999 / Accepted: August 19, 1999     

Accumulation of somatic hypermutation and antigen-driven selection in rapidly cycling surface Ig+ germinal center (GC) B cells which occupy GC at a high frequency during the primary antihapten response in mice

Well-developed germinal centers (GC) contain rapidly dividing surface immunoglobulin-negative (sIg^-) B cells (centroblasts), and most of their progeny are sIg⁺ B cells (centrocytes) in a resting state. It has been predicted that somatic hypermutation occurs in centroblasts, whereas antigen-driven selection takes place in centrocytes. The present analysis indicates that murine GC B cells bearing sIg with specificity for an immunizing antigen are in a rapidly cycling state and increase exponentially in number to occupy spleen GC at high frequency during the 1st week after primary immunization; however, the number of these cells is significantly reduced in the 2nd week of immunization. During that period, these proliferating sIg⁺ GC B cells accumulate somatic hypermutations with nucleotide exchanges indicative of affinity maturation. These sIg⁺ GC B cells co-express B7-2, ICAM-1, and LFA-1, and have potent antigen-presenting activity which results in T cell activation in vitro. These observations indicate that the sIg⁺ GC B cells accumulate somatic hypermutations and undergo antigen-driven selection through proliferation, probably upon activation by T cells. This sIg⁺ GC B cell population may represent cell cycling centrocytes; however, the possibility that these may represent centroblasts undergoing re-expression of sIg could not be excluded.