Synthesis of praziquantel derivatives and their in vitro activity against adult Clonorchis sinensis

Several praziquantel derivatives have been prepared by the acylation of compound 5, and examined on their biological activity in vitro a against adult Clonorchis sinensis collected from rabbits infected with metacercariae which was isolated from Pseudorasbora parva, a second intermediate host, captured in Nakdong river in Korea.

Effect of simultaneous pulsed hyperthermia and pulsed radiation treatment on survival of SiHa cells

Relatively mild temperatures (40-41.5 degrees C) can sensitize human cells to radiation without the development of thermal tolerance to radiosensitization. Therefore there may be a therapeutic benefit to adding mild hyperthermia to brachytherapy regimens for the treatment of cancer. However, the required heating times are long (approximately 48 h) which renders this approach somewhat impractical. A novel alternative is to combine pulsed brachytherapy with pulsed hyperthermia to enable the total radiation dose to be given at an elevated temperature while the total heating time is kept short. A treatment schedule in which 1 Gy radiation pulses were given once per hour during 5-min heating pulses also delivered once per hour, was investigated in vitro in the human cervical carcinoma line, SiHa. The degree of cytotoxicity and thermoradiosensitization of the cells were assessed by cell survival using the colony forming assay. Cells were exposed to pulsed hyperthermia alone (5 min at 45 degrees C, delivered once per hour), acute hyperthermia alone (45 degrees C), pulsed radiation alone (1 Gy per hour), acute radiation alone, and simultaneous pulsed hyperthermia and pulsed radiation. Pulsed heating alone caused little cytotoxicity. However when pulsed heating was added to pulsed radiation, the level of cytotoxicity was greater than for pulsed radiation alone or acute radiation alone. The effect was also greater than would be predicted from a simple additive effect of pulsed radiation and pulsed heating. In conclusion, pulsed heating at 45 degrees C sensitized cells to pulsed radiation without the development of thermal tolerance.

Immunohistochemical analysis of Fas ligand expression in sarcomas. Sarcomas express high level of FasL in vivo

Fas ligand (FasL) and its receptor, Fas, play a key role in the regulation of apoptosis within the immune system. Several prior experimental studies of Fas ligand expression in tumors have suggested a mechanism that enables tumors to evade immune destruction by inducing apoptosis in activated lymphocytes near the tumor cells. Many types of carcinomas have been shown to express FasL, but at present nothing is known about the range of sarcomas capable of expressing FasL in vivo. The aim of this study was to determine the in vivo patterns of FasL expression in human sarcomas. Archival paraffin-embedded tissues of 57 sarcomas and 30 carcinomas were analyzed by immunohistochemistry for the expression of FasL. FasL immunoreactivity was seen in 39 of 57 (68%) sarcomas, including 10 of 10 rhabdomyosarcomas, 5 of 5 malignant schwannomas, 2 of 2 Ewing's sarcomas, 8 of 11 malignant fibrous histiocytomas, 4 of 5 angiosarcomas, 2 of 5 synovial sarcomas, 2 of 5 liposarcomas, 3 of 5 leiomyosarcomas, 2 of 6 osteosarcomas, and 1 of 3 chondrosarcomas. All carcinomas tested (10 gastric adenocarcinomas, 10 hepatocellular carcinomas, and 10 renal cell carcinomas) were positive for FasL. These results demonstrate that FasL expression in sarcomas, although less frequent than in carcinomas, is widespread among the sarcoma types, and suggest that FasL might contribute to the immune escape of sarcomas through killing Fas-bearing lymphocytes.

Contribution of abnormal sarcoplasmic reticulum ATPase activity to systolic and diastolic dysfunction in human heart failure

Two of the most significant characteristics of failing human myocardium are an increased diastolic [Ca2+]i and a prolonged diastolic relaxation. These abnormalities are more pronounced at higher frequencies of stimulation and may be caused by an altered Ca2+ resequestration into the sarcoplasmic reticulum (SR). The force-frequency relationship was determined in multicellular preparations obtained from non-failing (n=6) and failing human myocardium (n=11). The active force in non-failing tissue increased as a function of the frequency of stimulation. In failing myocardium, an increase in frequency of stimulation (>1 Hz) was accompanied by a decrease in active force. Changes in the frequency of stimulation and active force were also associated with changes in intracellular calcium concentrations. The diastolic force in failing myocardium was augmented following an increase in frequency of stimulation, whereas in non-failing tissue, no increase in diastolic force was observed. Associated with the increase in diastolic force was an increase in intracellular diastolic calcium concentrations. The SR Ca2+ ATPase activity was reduced in failing compared to non-failing myocardium. SR Ca2+ ATPase was positively correlated with diastolic force in non-failing myocardium. The relationship between Ca2+ ATPase activity at 1 micromol/l [Ca2+] and active force between 0.5 and 2.0 Hz was different between failing and non-failing myocardium. The diastolic force demonstrate an inverse relationship with the SR Ca2+ ATPase activity in failing myocardium. These data suggest that a reduction in SR Ca2+ ATPase activity contributes to the impairment in both systolic and diastolic function of failing human hearts.

Effects of Ginkgo biloba extract on the cochlear damage induced by local gentamicin installation in guinea pigs

Investigations evaluating the protective effect of Ginkgo biloba extract (EGb) on gentamicin (GM) ototoxicity were undertaken. Guinea pigs treated with 5 mg/kg gentamicin sulfate on the round window niche (RWN) showed acute changes on electrocochleogram and hair cell or microvilli damage on scanning electron microscopy (SEM). There was accumulation of GM in the whole cochlea, especially in the organ of Corti, stria vascularis, and type III fibrocyte on immunohistochemical study. However, the guinea pigs pretreated with local or systemic EGb revealed no significant changes by local GM installation. From these results, we concluded that EGb has a protective effect on the development of GM ototoxicity in the cochlea.

Nickel (II)-induced apoptosis and G2/M enrichment

Treatment with certain DNA-damaging agents induce a complex cellular response comprising pertubation of cell cycle progression and/or apoptosis on proliferating mammalian cells. Our studies were focused on the cellular effects of nickel (II) acetate, DNA-damaging agent, on Chinese hamster ovary (CHO) cells. Fragmented DNAs were examined by agarose gel electrophoresis and cell cycle was determined by DNA flow cytometry using propidium iodide fluorescence. Apparent DNA laddering was observed in cells treated with 240 microM nickel (II) and increased with a concentration-dependent manner. Treatment of nickel (II) acetate resulted in apoptosis which was accompanied by G2/M cell accumulation. Proportion of CHO cells in G2/M phase was also significantly increased in cells exposed to at least 480 microM nickel (II) from 57.7% of cells in the G0/G1 phase, 34.7% in the S phase, and 7.6% in the G2/M1 phase for 0 microM nickel (II), to 58.6%, 14.5%, and 26.9% for 640 microM nickel (II). These findings suggest that nickel (II) can modulate cellular response through some common effectors involving in both apoptotic and cell cycle regulatory pathways.

Effect of supplemental beta-carotene on plasma concentrations of carotenoids, retinol, and alpha-tocopherol in humans

High doses of beta-carotene, a lipid-soluble nutrient, may affect the plasma concentrations of other lipid-soluble nutrients. The purpose of this study was to assess the effects of long-term daily supplementation with beta-carotene (50 mg/d) on circulating concentrations of other carotenoids, retinol, and alpha-tocopherol over time. Data were available from 259 men and women participating in the Carotene Prevention Trial, a 2-center chemoprevention trial designed to determine whether supplemental beta-carotene can prevent second malignant tumors in patients cured of an early stage cancer of the oral cavity, pharynx, or larynx. Up to 2 blood samples were obtained before the intervention (before and after a 1-mo placebo run-in), with postrandomization samples obtained at 3, 12, 24, 36, 48, and 60 mo. Supplementation with beta-carotene produced a persistent 9- to 10-fold increase in median plasma beta-carotene concentrations (225 nmol/L at baseline to 2255 nmol/L at 3 mo) and a persistent 2-fold increase in median plasma alpha-carotene concentrations (45 nmol/L at baseline to 95 nmol/L at 3 mo). Concentrations of retinol, alpha-tocopherol, lycopene, and lutein/zeaxanthin were not affected by supplemental beta-carotene. Up to 5 y of daily supplementation with beta-carotene increased circulating concentrations of alpha- and beta-carotene, but did not alter concentrations of lycopene, lutein/zeaxanthin, retinol, or alpha-tocopherol.

Frequent somatic mutations in serine/threonine kinase 11/Peutz-Jeghers syndrome gene in left-sided colon cancer

We analyzed somatic mutation and loss of heterozygosity (LOH) in the serine/threonine kinase 11 (STK11)/Peutz-Jeghers syndrome gene in 49 colorectal tumors in three different stages of a dysplasia-carcinoma sequence. We detected LOH in 10 of 19 (52.6%) informative colorectal cancers at loci D19S886 and/or D19S883, but no LOH was observed in 25 informative adenomas. We detected a total of 9 somatic mutations [7 of 13 (53.8%) left-sided colon cancers and 2 of 7 (28.6%) left-sided adenomas with high-grade dysplasia], but no mutations were detected in right-sided colon tumors. Of the nine mutations, one was a frameshift mutation (the same mutation detected in Peutz-Jeghers syndrome family previously), and the other eight were missense mutations. This results indicate that STK11 is a tumor suppressor gene and that genetic changes of STK11 play an important role in left-sided colon cancer carcinogenesis.

Quantitative low-dose assessment of seafood toxin, domoic acid, in the rat brain: application of physiologically-based pharmacokinetic (PBPK) modeling

The purpose of this study was to construct a physiologically based pharmacokinetic model and demonstrate its ability to predict low-dose uptake of domoic acid, a seafood contaminant, in discrete areas of the rat brain. The model we used was derived from the generic PBPK model of our previous studies with 2,4-dichlorophenoxyacetic acid (Kim et al., 1994. Pharmacokinetic modeling of 2,4-dichlorophenoxyacetic acid (2,4-D) in rats and in rabbits brain following single dose administration. Toxicol. Lett. 74, 189; Kim et al., 1995. Development of a physiologically based pharmacokinetic model for 2,4-dichlorophenoxyacetic acid dosimetry in discrete areas of the rabbit brain. Neurotoxicol. Teratol. 17, 111), to which physiological- and chemical-specific parameters for domoic acid were applied. It incorporates two body compartments along with compartments for venous and arterial blood, cerebrospinal fluid, brain plasma and seven brain regions. Uptake of the blood-borne toxin is membrane-limited by the blood-brain barrier with clearance from the brain provided by cerebrospinal fluid `sink' mechanisms. This model generated predicted profiles of toxin level in brain and blood over a 1-h period that compared reasonably well with concentrations calculated from in vivo data of rats that had been given [(3)H]domoic acid intravenously (Preston and Hynie, 1991. Transfer constants for blood-brain barrier permeation of the neuroexcitatory shellfish toxin, domoic acid. Can. J. Neurol. Sci. 18, 39). This PBPK model should be an effective tool for evaluating the target doses that produce the potential neurotoxicity of domoic acid found in foods.

Fas ligand is expressed in normal skin and in some cutaneous malignancies

Fas, a cell surface receptor and member of the tumour necrosis factor receptor superfamily, induces apoptosis upon oligomerization by its ligand (Fas ligand: FasL). Detailed studies have revealed that Fas is broadly expressed in normal human tissues, but relatively little is known about the range of cell types capable of expressing FasL. The aim of this study was to determine the in vivo patterns of expression of Fas and FasL in human skin tissues. Immunohistochemistry was performed using paraffin-embedded samples of normal and neoplastic skin tissues. In normal skin, FasL was expressed in the epidermis, sebaceous glands, sweat glands and outer root sheath of the hair. In squamous cell carcinomas (SCC), all cases analysed expressed FasL at high levels, whereas 60% of basal cell carcinomas (BCC) were positive for FasL. Expression of Fas in normal skin was observed in the basal and spinous layers of the epidermis, the outer root sheath of the hair, and the sebaceous glands. Expression of Fas was observed in all the SCC tested and none of the BCC tested. Expression of FasL by normal cells and tumour cells in skin tissue, demonstrated for the first time in the present study, may provide an important clue to understanding skin physiology, and immune evasion of skin tumours.

Control of intraoperative bleeding with hydrostatic pressure during endoscopic surgery

Though intracranial endoscopic surgery has several advantages, poor visibility caused by bleeding from the operative field is one of its limitations. In two cases involving endoscopic III ventriculostomy the authors encountered moderate bleeding, and this was controlled with 'water column tamponade.' Following the application of hydrostatic pressure of 40-50 cmH2O for less than 2 min, the bleeding temporarily stopped and the operative field became clear. Several applications of this tamponade made it possible to complete the procedures. Although the pressure applied by the water column was not high enough to disturb the cerebrovascular autoregulation, blood pressure rose significantly during application of the water column tamponade. This method was valuable for the completion of procedures when bleeding was not at high pressure from large arteries. Careful monitoring of the blood pressure is mandatory, and adjustment of the pressure applied will make the procedure safer.

Regional deposition of inhaled particles in human lungs: comparison between men and women

We measured detailed regional deposition patterns of inhaled particles in healthy adult male (n = 11; 25 +/- 4 yr of age) and female (n = 11; 25 +/- 3 yr of age) subjects by means of a serial bolus aerosol delivery technique for monodisperse fine [particle diameter (Dp) = 1 micron] and coarse aerosols (Dp = 3 and 5 micron). The bolus aerosol (40 ml half-width) was delivered to a specific volumetric depth (Vp) of the lung ranging from 100 to 500 ml with a 50-ml increment, and local deposition fraction (LDF) was assessed for each of the 10 local volumetric regions. In all subjects, the deposition distribution pattern was very uneven with respect to Vp, showing characteristic unimodal curves with respect to particle size and flow rate. However, the unevenness was more pronounced in women. LDF tended to be greater in all regions of the lung in women than in men for Dp = 1 micron. For Dp = 3 and 5 micron, LDF showed a marked enhancement in the shallow region of Vp </= 200 ml in women compared with men (P < 0.05). LDF in women was comparable to or smaller than those of men in deep lung regions of Vp > 200 ml. Total lung deposition was comparable between men and women for fine particles but was consistently greater in women than men for coarse particles regardless of flow rates used: the difference ranged from 9 to 31% and was greater with higher flow rates (P < 0.05). The results indicate that 1) particle deposition characteristics differ between healthy men and women under controlled breathing conditions and 2) deposition in women is greater than that in men.

A relapsed case of imported tertian malaria after a standard course of hydroxychloroquine and primaquine therapy

Resistance of Plasmodium species to antimalarial agents has become increasingly challenging to the management and prevention of malaria. We experienced an imported case of tertian malaria due to Plasmodium vivax relapsed after a seemingly successful treatment with conventional course of hydroxychloroquine and primaquine. A 35-year-old man developed fever three days after return from India and mainland China. After his illness was diagnosed as tertian malaria, he was managed with hydroxychloroquine and then primaquine (primaquine base 15 mg/day for 14 days). Thereafter peripheral blood smears showed no malarial parasites, and there was no relapse of symptom until the 55th post-treatment day, however, six months after the above treatment tertian malaria relapsed. He was managed with the same medications again and malaria did not relapse for 10 months.

Retention and intracellular distribution of instilled iron oxide particles in human alveolar macrophages

Bronchoalveolar lavage (BAL) was used to sample retention of particles within the alveolar macrophage (AM) compartment at various times from 1 to 91 d following intrapulmonary instillation of 2. 6-microm-diameter iron oxide (Fe2O3) particles in human subjects. Particles were cleared from the lavagable AM compartment in a biphasic pattern, with a rapid-phase clearance half-time of 0.5 d and long-term clearance half-time of 110 d, comparable to retention kinetics determined by more traditional methods. The intracellular distribution of particles within lavaged AMs was similar in bronchial and alveolar BAL fractions. AMs with high intracellular particle burdens disappeared from the lavagable phagocytic AM population disproportionately more rapidly (shorter clearance half-time) than did AMs with lower particle burdens, consistent with the occurrence of a particle redistribution phenomenon as previously described in similar studies in rats. The rates of AM disappearance from the various particle burden categories was generally slightly slower in bronchial fractions than in alveolar fractions. The instillation of particles induced a transient acute inflammatory response at 24 h postinstillation (PI), characterized by increased numbers of neutrophils and alveolar macrophages in BAL fluids. This response was subclinical and was resolved within 4 d PI.

Platelet endothelial cell adhesion molecule-1 expression modulates endothelial cell migration in vitro

Endothelial cell migration is an important process that occurs during embryonic vasculogenesis and angiogenesis, wound healing, and tumor growth and metastasis, and after denudation injury following angioplasty and bypass grafting. Mechanisms regulating this process involve a complex interplay of cytoskeletal reorganization, cell-cell adhesion, and cell-extracellular matrix interactions. Platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) is constitutively expressed in endothelial cells, leukocytes, monocytes, lymphocytes, and platelets. PECAM-1 undergoes dynamic dephosphorylation during endothelial cell migration in vitro and during vasculogenesis in the murine conceptus. In transfected 3T3 cells, in cultured endothelial cells, and in the murine conceptus undergoing vasculogenesis, the tyrosine phosphorylation state of PECAM-1 Y686 correlates with the migratory state of the cells. In the present study, we investigate the role of PECAM-1 in modulating endothelial cell migration in vitro using retroviral transduction of c-myc epitope-tagged, wild-type, Y686 to F-mutated PECAM-1 and extracellular domain-deleted PECAM-1 constructs in endothelial cells devoid of endogenous PECAM-1 (ECV304 cells) and in endothelial cells expressing high levels of endogenous PECAM-1 (bovine aortic endothelial cells, BAEC). In ECV304 cells, the expression of wild-type PECAM-1 inhibited migration rates, whereas in BAEC, overexpression of wild-type PECAM-1 had no effect. Expression of Y686 to F-mutated PECAM-1 or extracellular domain-deleted PECAM-1 in BAEC increased migration rates. These data support the concept that endothelial cell migration is modulated, in part, by a balance between PECAM-1 cytoplasmic domain-mediated "inside-out" and "outside-out" signaling resulting from PECAM-1-mediated cell-cell interactions and integrin-extracellular matrix interactions.

Detection of soluble Fas mRNA using in situ reverse transcription-polymerase chain reaction

Fas protein (Fas) is known to induce cell death by apoptosis in susceptible cells. Alternative splicing of the Fas gene produces soluble Fas protein (sFas), which is considered to block the function of Fas. The serum level of sFas is elevated in patients with various malignancies in a manner reflective of disease stage and tumor burden, but the precise cellular origin of sFas in vivo has not yet been clarified. To identify the cells that synthesize sFas mRNA on histologic specimens, we applied in situ reverse transcription-polymerase chain reaction (in situ RT-PCR) in 11 cases of gastric adenocarcinoma/metastatic lymph node. Furthermore, we studied the distribution of Fas using immunohistochemistry and Fas mRNA using in situ RT-PCR. In all primary tumors and 10 of 11 metastatic tumors, tumor cells expressed both Fas- and sFas mRNA. Lymphocytes infiltrated in the tumor tissues and the lymph nodes also revealed both mRNA signals. A clear correlation between the tissue distribution for Fas and its mRNA was also observed. These observations demonstrated that solid tumors in vivo can synthesize sFas mRNA and suggest that tumor cells are responsible in part for elevated sFas in human malignancies. However, the additional expression of sFas mRNA in tissue lymphocytes indicates the complex regulatory mechanisms of Fas-mediated apoptosis pathway in tumor pathogenesis and host defense. We also demonstrated that in situ RT-PCR can be a suitable method for in situ detection of alternatively spliced mRNA.

Loss of heterozygosity and somatic mutations of the VHL tumor suppressor gene in sporadic cerebellar hemangioblastomas

Cerebellar hemangioblastoma is a benign central nervous system neoplasm with characteristic proliferation of vascular and stromal cells. There is increasing evidence that the stromal cell population may represent the neoplastic component of hemangioblastoma, whereas the vascular component may be composed of reactive, nonneoplastic cells. Therefore, successful genetic testing for loss of heterozygosity requires selective analysis of target cell populations. Here, tissue microdissection was used to selectively analyze the stromal cell component of 20 archival sporadic cerebellar hemangioblastomas for loss of heterozygosity at the Von-Hippel Lindau (VHL) gene and somatic VHL gene mutations. Allelic deletions at the VHL gene locus were detected in the stromal cell component with one or more markers (D3S1038, D3S1110, and/or 104/105) in 10 of 19 (52.6%) informative cases. In all cases, heterozygosity at the VHL gene locus was retained in the vascular component. In two cases, aberrant bands in exon 2 of the VHL gene were demonstrated in the stromal cells by PCR-based single-strand conformation polymorphism analysis, and somatic missense mutations were successfully characterized in two of the sporadic hemangioblastomas by direct sequencing. The results suggest that allelic losses and mutations of the VHL tumor suppressor gene play a role in sporadic cerebellar hemangioblastoma tumorigenesis. Furthermore, because the genetic changes were detected in selectively procured stromal cell areas, the data provide strong evidence that the stromal cell represents a neoplastic component of hemangioblastoma.

Correlation between nasal obstruction symptoms and objective parameters of acoustic rhinometry and rhinomanometry

Acoustic rhinometry and rhinomanometry have been used to assess nasal airway patency objectively. We compared nasal obstruction symptoms before and after decongestion with several parameters of these objective tests. The patients assessed their nasal obstruction using a visual analogue scale (VAS). Cross-sectional areas and nasal resistance were measured by acoustic rhinometry and rhinomanometry before and after topical application of 1% phenylephrine solution in 32 patients with nasal obstruction symptoms. There was no significant correlation between the difference in the VAS and the difference in nasal resistance. There was also no significant correlation between the difference in the VAS and minimal cross-sectional area and cross-sectional areas at 3.3 cm (CA3.3), CA4.0 and CA6.4 from the nosepiece both in the wide and narrow sides and in both nasal cavities before and after nasal decongestion. It is concluded that rhinomanometry and acoustic rhinometry may have no diagnostic value in estimating the severity of nasal obstruction symptoms.

Fractal coding of video sequence using circular prediction mapping and noncontractive interframe mapping

We propose a novel algorithm for fractal video sequence coding, based on the circular prediction mapping and the noncontractive interframe mapping. The proposed algorithm can effectively exploit the temporal correlation in real image sequences, since each range block is approximated by the domain block in the adjacent frame, which is of the same size as the range block. The computer simulation results demonstrate that the proposed algorithm provides very promising performance at low bit rate, ranging from 40-250 kbyte/s.

A fractal vector quantizer for image coding

We investigate the relation between VQ (vector quantization) and fractal image coding techniques, and propose a novel algorithm for still image coding, based on fractal vector quantization (FVQ). In FVQ, the source image is approximated coarsely by fixed basis blocks, and the codebook is self-trained from the coarsely approximated image, rather than from an outside training set or the source image itself. Therefore, FVQ is capable of eliminating the redundancy in the codebook without any side information, in addition to exploiting the self-similarity in real images effectively. The computer simulation results demonstrate that the proposed algorithm provides better peak signal-to-noise ratio (PSNR) performance than most other fractal-based coders.

Depressed Langerhans cell migration and reduced contact hypersensitivity response in mice lacking TNF receptor p75

Epidermal Langerhans cells (LC) belong to the dendritic cell family and represent the major APC within the skin. LC capture epicutaneous Ag, migrate into regional lymph nodes, and present Ag to T cells, thereby initiating primary immune response. The migratory properties of LC are an essential component of their function. The molecular mechanisms responsible for LC migration are far less defined. However, evidence has been accumulating to suggest that TNF-alpha, a major proinflammatory cytokine, plays an important role in promoting DC migration. To confirm the role of TNF-alpha in LC migration and to examine which type of TNF receptor signaling is involved in such an event, we utilized gene-targeted knockout mice lacking TNF receptor p55 or p75. The migration of LC was assessed by examining the frequency of hapten-bearing cells in draining lymph nodes following hapten FITC painting, and the accumulation of dendritic cells in draining lymph nodes after intradermal injection of TNF-alpha. While LC migration was normal in p55-deficient mice, the migration was markedly depressed in p75-deficient mice. Receptor p75-deficient mice also demonstrated a hyporesponsiveness in allergen-induced contact dermatitis, but a normal responsiveness in irritant-induced contact dermatitis. These results suggest that p75-dependent signaling plays a crucial role in the migration of LC and in the initiation of cutaneous immune responses.

Panhandle polymerase chain reaction amplifies MLL genomic translocation breakpoint involving unknown partner gene

We used a new approach called panhandle polymerase chain reaction (PCR) to clone an MLL genomic translocation breakpoint in a case of acute lymphoblastic leukemia of infancy in which karyotype analysis was technically unsuccessful and did not show the translocation partner. Panhandle PCR amplified known MLL sequence 5' of the breakpoint and 3' sequence from the unknown partner gene from a DNA template with an intrastrand loop schematically shaped like a pan with a handle. The 7-kb panhandle PCR product contained the translocation breakpoint in MLL intron 8. The partner DNA included unique nonrepetitive sequences, Alu and mammalian apparent LTR-retrotransposon (MaLR) repetitive sequences, and a region of homology to expressed sequence tags. MaLR sequences have not been found before near leukemia-associated translocation breakpoints. The nonrepetitive sequences were not homologous to known partner genes of MLL. Screening of somatic cell hybrid and radiation hybrid lines by PCR and fluorescence in situ hybridization analysis of normal metaphase chromosomes mapped the partner DNA to chromosome band 4q21. Reverse transcriptase-PCR identified an MLL-AF-4 chimeric mRNA, indicating that panhandle PCR identified a fusion of MLL with a previously uncharacterized AF-4 intronic sequence. Panhandle PCR facilitates cloning translocation breakpoints and identifying unknown partner genes.

Depressed Langerhans cell migration and reduced contact hypersensitivity response in mice lacking TNF receptor p75

Epidermal Langerhans cells (LC) belong to the dendritic cell family and represent the major APC within the skin. LC capture epicutaneous Ag, migrate into regional lymph nodes, and present Ag to T cells, thereby initiating primary immune response. The migratory properties of LC are an essential component of their function. The molecular mechanisms responsible for LC migration are far less defined. However, evidence has been accumulating to suggest that TNF-alpha, a major proinflammatory cytokine, plays an important role in promoting DC migration. To confirm the role of TNF-alpha in LC migration and to examine which type of TNF receptor signaling is involved in such an event, we utilized gene-targeted knockout mice lacking TNF receptor p55 or p75. The migration of LC was assessed by examining the frequency of hapten-bearing cells in draining lymph nodes following hapten FITC painting, and the accumulation of dendritic cells in draining lymph nodes after intradermal injection of TNF-alpha. While LC migration was normal in p55-deficient mice, the migration was markedly depressed in p75-deficient mice. Receptor p75-deficient mice also demonstrated a hyporesponsiveness in allergen-induced contact dermatitis, but a normal responsiveness in irritant-induced contact dermatitis. These results suggest that p75-dependent signaling plays a crucial role in the migration of LC and in the initiation of cutaneous immune responses.