Requirement of Fas for the Development of Autoimmune Diabetes in Nonobese Diabetic Mice

Insulin-dependent diabetes mellitus (IDDM) is assumed to be a T cell–mediated autoimmune disease. To investigate the role of Fas-mediated cytotoxicity in pancreatic β cell destruction, we established nonobese diabetic (NOD)-lymphoproliferation (lpr)/lpr mice lacking Fas. Out of three genotypes, female NOD-+/+ and NOD-+/lpr developed spontaneous diabetes by the age of 10 mo with the incidence of 68 and 62%, respectively. In contrast, NOD-lpr/lpr did not develop diabetes or insulitis. To further explore the role of Fas, adoptive transfer experiments were performed. When splenocytes were transferred from diabetic NOD, male NOD-+/+ and NOD-+/lpr developed diabetes with the incidence of 89 and 83%, respectively, whereas NOD-lpr/lpr did not show glycosuria by 12 wk after transfer. Severe mononuclear cell infiltration was revealed in islets of NOD-+/+ and NOD-+/lpr, whereas islet morphology remained intact in NOD-lpr/lpr. These results suggest that Fas-mediated cytotoxicity is required to initiate β cell autoimmunity in NOD mice. Fas–Fas ligand system might be critical for autoimmune β cell destruction leading to IDDM.     

Neurotoxicodynamics of the Interaction between Ciprofloxacin and Foscarnet in Mice

The potential for convulsions induced by the coadministration of ciprofloxacin (CPFX) and foscarnet (PFA) may be due not to a change in the distribution of CPFX to the brain but to a potential CPFX-induced inhibition of γ-aminobutyric acid (GABA)-GABA_A receptor binding in the presence of PFA.     

Bedside analysis of human milk for adjustable nutrition strategy

Aim: Mother's milk is optimum for preterm infants, but human milk fortifier is required at times, because some nutrients are sometimes insufficient for infant growth. It is important to measure the nutrients in breast milk at bedside so that the amount of nutrients that need to be supplemented can be determined. A human milk analyser (HMA, Miris®) is currently available. We examined if the macronutrient values measured by human milk analyser are comparable with those measured by conventional methods. We also sought to discover whether we could dilute the milk sample used for the human milk analyser measurement if the amount of milk available for testing was insufficient.
Subjects and Methods: First, the results of protein, fat and lactose content in breast milk samples obtained using the human milk analyser and conventional methods were compared. Second, we measured diluted samples and compared the values with nondiluted samples.
Results: When comparing the human milk analyser and conventional methods, all three nutrients exhibited a significantly positive correlation (p < 0.001); lactose content was reliable on the condition that it is 6–7 g/dL. The lactose content measured by the HPLC method was obtained by 3.05 × human milk analyser value − 13.4. When comparing diluted and nondiluted samples, fat and protein had expected values after dilution whereas lactose did not.
Conclusion: The human milk analyser can inform us about the amount of major nutrients in breast milk: fat, protein and lactose. However, when human milk is diluted, the lactose content measured by the human milk analyser is overestimated.     

Identification of a novel tobacco DnaJ-like protein that interacts with the movement protein of tobacco mosaic virus

The movement protein (MP) of tobacco mosaic virus (TMV) mediates the transport of viral RNA from infected cells to neighboring uninfected cells via plasmodesmata by interacting with putative host factors. To find such host factors, we screened tobacco proteins using the yeast two-hybrid system. NtMPIP1, a novel subset of DnaJ-like proteins, was identified from a tobacco cDNA library, and its specific interaction with TMV MP was confirmed with an in vitro filter-binding assay. In a deletion analysis, using a series of truncated TMV MPs and NtMPIP1s, at least two regions of TMV MP, amino acid residues 65–86 and 120–185, conferred the ability to interact with the C-terminal domain of NtMPIP1, which is thought to be involved in substrate binding. Virus-induced gene silencing of NtMPIP1 significantly inhibited the spread of TMV. Therefore, it is reasonable to consider that endogenous NtMPIP1 is a host factor involved in virus cell-to-cell spread by interacting with TMV MP. Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession number AB092334.     

Takotsubo cardiomyopathy

Takotsubo cardiomyopathy (TC) is characterized by transient left ventricular apical wall motion abnormalities, chest pain with electrocardiographic changes, and modest myocardial enzymatic release mimicking acute coronary syndrome, but without significant coronary artery disease. TC is an increasingly recognized type of acquired cardiomyopathy occurring commonly after a recent stressful event, in particular emotional stress, and is relatively common in middle-aged and older women. The pathogenetic mechanism remains unknown. Catecholamine surge related to emotional distress seems to play a major role in the pathogenesis of this cardiomyopathy, rendering TC a type of neurocardiological disorder that manifests as acute but reversible heart failure. Clinicians should consider this syndrome in the differential diagnosis of patients presenting with clinical findings suggestive of acute coronary syndrome, especially in postmenopausal women with a recent history of acute emotional or physical stress.     

Hepatic tumors induced by carbon tetrachloride in transgenic mice carrying a human c-H-ras proto-oncogene without mutations

Hepatic tumors were generated in mice by repeated administration of carbon tetrachloride (CCI₄). Eight transgenic (Tg) mice carrying a human c-H-ras proto-oncogene (rasH2 line) and 9 non-Tg mice were killed at 20 weeks. Tg mice developed more tumors than did non-Tg littermates. Most tumors were neoplastic nodules, but I hepatocellular carcinoma (HCC) was found in a Tg mouse at 20 weeks. Three Tg and 2 non-Tg mice were kept without further administration of CCI₄. Two Tg mice died at 30 weeks of HCC with intra-abdominal bleeding, and I Tg mouse developed HCC with a mesenteric metastasis at 32 weeks. No HCC was found in 2 non-Tg mice at 32 weeks. Although mutations at codon 12, 13, and 61 of the H-ras gene are often found in murine hepatocarcinogenesis, neither the tumors, including one HCC, nor the normal cells revealed any such mutations. These results showed that the unmutated human c-H-ras gene facilitates malignant transformation of hepatocytes when continuous liver-cell death and regeneration is caused by repeated administration of CCI₄. © 1994 Wiley-Liss, Inc.     

Screening of various plant extracts used in ayurvedic medicine for inhibitory effects on human immunodeficiency virus type 1 (HIV-1) protease

To identify substances with anti-human immunodeficiency virus (HIV) activity in traditional medicines, water and methanol extracts of crude drugs used in Indian traditional medicine (Ayurveda) were subjected to screening for their inhibitory effects on HIV type 1 protease (PR). The enzyme activity was determined by HPLC and of the 39 crude drugs tested, the extracts of the seeds of Areca catechu, the bark of Eugenia jambolana, the bark of Saraca indica and the stem bark of Terminalia arjuna inhibited the HIV-1 PR activity by more than 70% at a concentration of 0.2 mg/mL. The most potent inhibition was shown by the A. catechu extract, from which some procyanidins were isolated. One of them, arecatannin B1 showed significant HIV-1-PR inhibitory activity.     

Genetic Complementation of the Immortal Phenotype in Group D Cell Lines by Introduction of Chromosome 7

Human immortal cell lines have been classified into at least four (A–D) genetic complementation groups by cell-cell hybrid analysis, i.e., a hybrid derived from different groups becomes mortal. Recently we have demonstrated that introduction of human chromosome 7 suppresses indefinite division potential in the non-tumorigenic human immortalized fibroblast lines KMST-6 and SUSM-1, both assigned to complementation group D. By extending our microcell-mediated chromosome transfer, we found that chromosome 7 also suppresses division potential in the human hepatoma line HepG2 (again, assigned to group D). Chromosome 7 was thus shown to suppress indefinite growth in the above group D cell lines irrespective of their cell types, or whether they are tumorigenic or not. Since chromosome 7 had no such effect on representative cell lines derived from complementation group A, B or C, these results indicate that the senescence gene(s) commonly mutated in the group D cell lines is located on chromosome 7.     

Rapid induction of more malignant tumors by various genotoxic carcinogens in transgenic mice harboring a human prototype c-Ha-ras gene than in control non-transgenic mice

In this study, we investigated the carcinogenic response oftransgenic mice carrying the human prototype c-Ha-ras gene,namely Tg rasH2/CB6F1 mice, to various genotoxic carcinogensand compared it with that of control non-transgenic CB6F1 mice(non-Tg mice). The present studies were conducted as the firststep in the evaluation of the Tg rasH2/CB6F1 mouse as a modelfor the rapid carcinogenicity testing system. Short-term (     

Cholinergic dysfunction in cognitive impairments after aneurysmal subarachnoid hemorrhage

OBJECTIVE: Although cognitive impairments have been observed after subarachnoid hemorrhage (SAH), little is known about their neurobiological bases. To examine cholinergic function in such patients, we used a known test for Alzheimer's disease based on an exaggerated pupil dilation response to a cholinergic antagonist, tropicamide (the tropicamide drop test). METHODS: Seventeen patients who were treated surgically after aneurysmal SAH were divided into two groups on the basis of their scores on the Mini-Mental State Examination (MMSE): Group A (MMSE > or =28) and Group B (MMSE < or =27). The mean interval of time between surgery and administration of the MMSE was 4.7 +/- 2.1 years for Group A and 4.2 +/- 1.3 years for Group B. The tropicamide drop test was performed within 1 month after the MMSE for each patient. After measurement of the baseline pupil diameter (R1, right pupil size: L1, left pupil size), one drop of 0.01% tropicamide was applied to the right eye and physiological saline to the left eye. Pupil diameter (R2, right pupil size; L2, left pupil size) was then remeasured. Data were represented as the dilation ratio of the right pupil (R2/R1) and as the relative dilation ratio of the right pupil to that of the left pupil (R2L1/R1L2). RESULTS: The mean dilation ratio of the right pupil (R2/R1) was higher in Group B (1.13 +/- 0.09) than in Group A (1.07 +/- 0.11), although the difference did not reach statistical significance (P = 0.18). The relative dilation ratio (R2L1/R1L2) was significantly higher in Group B (1.41 +/- 0.36) than in Group A (1.06 +/- 0.20) (P < 0.05). CONCLUSION: We determined cholinergic dysfunction in patients with cognitive impairment after SAH on the basis of the pupillary response to tropicamide. The results provide an insight into the pathophysiology of cognitive impairments after SAH, which might lead to future treatment strategies.