Hyo-Min Kang

Human neural stem cells overexpressing choline acetyltransferase restore cognitive function of kainic acid-induced learning and memory deficit animals.

Alzheimer disease (AD) is a progressive neurodegenerative disease, which is characterized by loss of memory and cognitive function. In AD patients dysfunction of the cholinergic system is the main cause of cognitive disorders, and decreased activity of choline acetyltransferase (ChAT), an enzyme responsible for acetylcholine (ACh) synthesis, is observed. In the present study we investigated if brain transplantation of human neural stem cells (NSCs) genetically modified to encode ChAT gene improves cognitive function of kainic acid (KA)-induced learning deficit rats. Intrahippocampal injection of KA to hippocampal CA3 region caused severe neuronal loss, resulting in profound learning and memory deficit. F3.ChAT human NSCs transplanted intracerebroventricularly improved fully the learning and memory function of KA-induced learning deficit animals, in parallel with the elevation of ACh levels in cerebrospinal fluid. F3.ChAT human NSCs migrated to the KA-induced injury site (CA3) and differentiated into neurons and astrocytes. The present study demonstrates that human NSCs expressing ChAT have lesion-tropic property and improve cognitive function of learning deficit model rats with hippocampal injury by increasing ACh level.

Preventive effect of piperonyl butoxide on cyclophosphamide-induced teratogenesis in rats

BACKGROUND Cyclophosphamide induces fetal defects through metabolic activation by cytochrome P-450 monooxygenases (CYP). The effects of piperonyl butoxide (PBO), a CYP inhibitor, on the fetal development and external, visceral, and skeletal abnormalities induced by cyclophosphamide were investigated in rats. METHODS Pregnant rats were daily administered PBO (400 mg/kg) by gavage for 7 days (the 6th to 12th day of gestation), and intraperitoneally administered with cyclophosphamide (12 mg/kg) 4 h after the final treatment. On the 20th day of gestation, maternal and fetal abnormalities were determined by Cesarean section. RESULTS Cyclophosphamide reduced fetal body weights by 30-40% without increasing resorption or death. In addition, it induced malformations in live fetuses: 100, 98, and 98.2% of the external (head and limb defects), visceral (cerebroventricular dilatation, cleft palate, and renal pelvic/ureteric dilatation), and skeletal (acrania, vertebral/costal malformations, and delayed ossification) abnormalities, respectively. The pre-treatment of PBO greatly decreased mRNA expression and activity of hepatic CYP2B, which metabolizes cyclophosphamide into teratogenic acrolein and cytotoxic phosphoramide mustard. Moreover, PBO remarkably attenuated cyclophosphamide-induced body weight loss and abnormalities of fetuses; score 3.57 versus 1.87 for exencephaly, 75.5% versus 42.5% for limb defects, 65.3% versus 22% for cerebroventricular dilatation, 59.2% versus 5.1% for cleft palate, score 1.28 versus 0.93 for renal pelvic/ureteric dilatation, 71.9-82.5% versus 23-45.9% for vertebral/costal malformations, and 84.2% versus 57.4% for delayed ossification in cyclophosphamide alone and PBO co-administration groups. CONCLUSIONS These results suggest that repeated treatment with PBO may improve cyclophosphamide-induced body weight loss and malformations of fetuses by down-regulating CYP2B.

What is your diagnosis? Lymph node aspirates from a dog with stillbirth

A 3-year-old female Miniature Schnauzer was presented to Chungbuk National University College of Veterinary Medicine with hyperthermia and vaginal discharge. Symptoms had started 2 days previously when the dog had whelped stillborn puppies. Before the pregnancy, the owner had noticed a symmetric subcutaneous mass in the cervical area, but had not sought treatment because the dog appeared otherwise healthy at the time. At first presentation, symptoms included depression and anorexia. Physical examination revealed hyperthermia (39.9°C), tachypnea, persistent dark-green vaginal discharge, abdominal distention, and generalized peripheral lymphadenopathy. Radiographic and ultrasonographic examinations of the thorax and abdomen revealed systemic lymph node enlargement, splenomegaly, hepatomegaly, ascites, and uterine distention. The CBC results included anemia (PCV 26.1%, reference interval [RI] 37–55%). Fine-needle aspirates (FNA) were obtained from enlarged lymph nodes and the spleen (Figure 1), and smears were prepared for cytologic examination. A