Lung fibrosis in Sprague-Dawley rats, induced by exposure to manual metal arc-stainless steel welding fumes

To investigate the disease process of pneumoconiosis induced by welding-fume exposure, a lung fibrosis model was established by building a stainless steel arc welding fume generation system and exposing male Sprague-Dawley rats for 90 days. The rats were exposed to welding fumes with concentrations of 57-67 mg/m3 (low dose) and 105-118 mg/m3 (high dose) total suspended particulates for 2 h per day in an inhalation chamber for 90 days. The concentrations of the main metals, Fe, Mn, Cr, and Ni, were measured in the welding fumes, plus the gaseous compounds, including nitrous gases and ozone, were monitored. During the exposure period, the animals were sacrificed after the initial 2-h exposure and after 15, 30, 60, and 90 days. Histopathological examinations were conducted on the animals' upper respiratory tract, including the nasal pathway and conducting airway, plus the gas exchange region, including the alveolar ducts, alveolar sacs, and alveoli. When compared to the control group, the lung weights did not increase significantly in the low-dose group, yet in the high-dose group there was a significant increase from day 15 to day 90. The histopathological examination combined with fibrosis-specific staining (Masson's trichrome) indicated that the lungs in the low-dose group did not exhibit any progressive fibrotic changes. Whereas, the lungs in the high-dose group exhibited early delicate fibrosis from day 15, which progressed into the perivascular and peribronchiolar regions by day 30. Interstitial fibrosis appeared at day 60 and became prominent by day 90, along with the additional appearance of pleural fibrosis. Accordingly, it would appear that a significant dose of welding-fume exposure was required to induce lung fibrosis.

Hemifacial seizure of cerebellar ganglioglioma origin: seizure control by tumor resection

The cerebellum is known to have an inhibitory effect on seizures. Nevertheless, cerebellar dysplastic lesions can be epileptogenic. A 4-month-old infant had paroxysmal facial contractions; tachypnea and nystagmoid eyeball and tremulous movements were occasionally combined. These evolved to stereotypic clinical patterns and frequencies, which increased despite administration of antiepileptic drugs (AEDs). Magnetic resonance imaging (MRI) demonstrated a mass arising from the superior cerebellar peduncle, although video-scalp EEG monitoring revealed no abnormal findings. Positron emission tomography with [(18)F]fluorodeoxyglucose revealed focal hypermetabolism in the same area identified by MRI. A depth electrode implanted in the mass revealed focal spike-and-wave discharges. The lesion was partly removed; pathologic diagnosis was ganglioglioma. Because of incomplete seizure control and residual tumor visible on MRI, a second operation was performed. After complete excision of the tumor, the patient became seizure free without AEDs. This case confirms the presence of seizure originating from the cerebellum and emphasizes the need for the complete removal of an epileptogenic lesion.

The crystal structure of chorismate lyase shows a new fold and a tightly retained product

The enzyme chorismate lyase (CL) catalyzes the removal of pyruvate from chorismate to produce 4-hydroxy benzoate (4HB) for the ubiquinone pathway. In Escherichia coli, CL is monomeric, with 164 residues. We have determined the structure of the CL product complex by crystallographic heavy-atom methods and report the structure at 1.4-A resolution for a fully active double Cys-to-Ser mutant and at 2.0-A resolution for the wild-type. The fold involves a 6-stranded antiparallel beta-sheet with no spanning helices and novel connectivity. The product is bound internally, adjacent to the sheet, with its polar groups coordinated by two main-chain amides and by the buried side-chains of Arg 76 and Glu 155. The 4HB is completely sequestered from solvent in a largely hydrophobic environment behind two helix-turn-helix loops. The extensive product binding that is observed is consistent with biochemical measurements of slow product release and 10-fold stronger binding of product than substrate. Substrate binding and kinetically rate-limiting product release apparently require the rearrangement of these active-site-covering loops. Implications for the biological function of the high product binding are considered in light of the unique cellular role of 4HB, which is produced by cytoplasmic CL but is used by the membrane-bound enzyme 4HB octaprenyltransferase.

Requirement for high mobility group protein HMGI-C interaction with STAT3 inhibitor PIAS3 in repression of alpha-subunit of epithelial Na+ channel (alpha-ENaC) transcription by Ras activation in salivary epithelial cells

Previously, we have demonstrated that oxidative stress or Ras/ERK activation leads to the transcriptional repression of alpha-subunit of epithelial Na(+) channel (ENaC) in lung and salivary epithelial cells. Here, we further investigated the coordinated molecular mechanisms by which alpha-ENaC expression is regulated. Using both stable and transient transfection assays, we demonstrate that the overexpression of high mobility group protein I-C (HMGI-C), a Ras/ERK-inducible HMG-I family member, represses glucocorticoid receptor (GR)/dexamethasone (Dex)-stimulated alpha-ENaC/reporter activity in salivary epithelial cells. Northern analyses further confirm that the expression of endogenous alpha-ENaC gene in salivary Pa-4 cells is suppressed by an ectopic HMGI-C overexpression. Through yeast two-hybrid screening and co-immunoprecipitation assays from eukaryotic cells, we also discovered the interaction between HMGI-C and PIAS3 (protein inhibitor of activated STAT3 (signal transducer and activator of transcription 3)). A low level of ectopically expressed PIAS3 cooperatively inhibits GR/Dex-dependent alpha-ENaC transcription in the presence of HMGI-C. Reciprocally, HMGI-C expression also coordinately enhances PIAS3-mediated repression of STAT3-dependent transactivation. Moreover, overexpression of antisense HMGI-C construct is capable of reversing the repression mediated by Ras V12 on GR- and STAT3-dependent transcriptional activation. Together, our results demonstrate that Ras/ERK-mediated induction of HMGI-C is required to effectively repress GR/Dex-stimulated transcription of alpha-ENaC gene and STAT3-mediated transactivation. These findings delineate a network of inhibitory signaling pathways that converge on HMGI-C.PIAS3 complex, causally associating Ras/ERK activation with the repression of both GR and STAT3 signaling pathways in salivary epithelial cells.

Intractable epilepsy associated with brain tumors in children: surgical modality and outcome

OBJECTS

The aim of this study was to evaluate the role of surgical modality in children with brain tumors and intractable epilepsy.

METHODS

Twenty-three patients who were treated for brain tumors and intractable epilepsy between January 1985 and March 1998 were retrospectively reviewed. The most common tumors were dysembryoplastic neuroepithelial tumors (n=9), oligodendrogliomas (n=6), and gangliogliomas (n=5). Six patients exhibited cortical dysplasia. The mean duration of follow-up was 43.4 months (range 12 to 125 months). Seizure outcome was more favorable (Engel's classes I and II) in patients with a complete resection of tumor (14/14 vs 6/9 for incomplete resection; P<0.05). There was no significant difference in seizure outcome between lesionectomy (n=13) and epilepsy surgery (n=10). The likelihood of requiring postoperative antiepileptic drugs was not influenced by the extent of resection or type of surgery.

CONCLUSIONS

On the basis of this study, we conclude that the complete resection of these tumors can be an appropriate initial treatment for children with brain tumors who experience intractable epilepsy.

Extracellular glutathione inhibits oxygen-induced permeability changes in alveolar epithelial monolayers

Exposure to high fractional inspired oxygen for 24 h increases permeability of the alveolar epithelium, contributing to the clinical manifestations of oxygen toxicity. Utilizing a model of the alveolar epithelium in which isolated rat type II cells form polarized monolayers on polycarbonate filters [transepithelial resistance (R(t)) > 1 k Omega x cm(2) by day 4], we evaluated the ability of reduced glutathione (GSH) to ameliorate these changes. On day 4, apical fluid was replaced with culture medium containing 1) no additives, 2) GSH (500 microM), or 3) GSH (500 microM) + glutathione reductase (0.5 U/ml) + nicotinamide adenine dinucleotide phosphate (250 microM). Monolayers were exposed (for 24 h) to room air (control) or 95% O(2), each containing 5% CO(2). After 24 h of hyperoxia, R(t) for condition 1 decreased by 45% compared with control (P < 0.001). In conditions 2 and 3, R(t) did not decrease significantly (P = not significant). Hyperoxia-induced decreases in active ion transport were observed for conditions 1 and 2 (P < 0.05), but not for condition 3 (P = not significant). These findings indicate that extracellular GSH may protect the alveolar epithelium against hyperoxia-induced injury. Addition of glutathione reductase and nicotinamide adenine dinucleotide phosphate may further augment these protective effects of GSH.

Vitreoscilla hemoglobin. Intracellular localization and binding to membranes

The obligate aerobic bacterium, Vitreoscilla, synthesizes elevated quantities of a homodimeric hemoglobin (VHb) under hypoxic growth conditions. Expression of VHb in heterologous hosts often enhances growth and product formation. A role in facilitating oxygen transfer to the respiratory membranes is one explanation of its cellular function. Immunogold labeling of VHb in both Vitreoscilla and recombinant Escherichia coli bearing the VHb gene clearly indicated that VHb has a cytoplasmic (not periplasmic) localization and is concentrated near the periphery of the cytosolic face of the cell membrane. OmpA signal-peptide VHb fusions were transported into the periplasm in E. coli, but this did not confer any additional growth advantage. The interaction of VHb with respiratory membranes was also studied. The K(d) values for the binding of VHb to Vitreoscilla and E. coli cell membranes were approximately 5-6 microm, a 4-8-fold higher affinity than those of horse myoglobin and hemoglobin for these same membranes. VHb stimulated the ubiquinol-1 oxidase activity of inverted Vitreoscilla membranes by 68%. The inclusion of Vitreoscilla cytochrome bo in proteoliposomes led to 2.4- and 6-fold increases in VHb binding affinity and binding site number, respectively, relative to control liposomes, suggesting a direct interaction between VHb and cytochrome bo.

Exponential Gain and Saturation of a Self-Amplified Spontaneous Emission Free-Electron Laser

Self-amplified spontaneous emission in a free-electron laser has been proposed for the generation of very high brightness coherent x-rays. This process involves passing a high-energy, high-charge, short-pulse, low-energy-spread, and low-emittance electron beam through the periodic magnetic field of a long series of high-quality undulator magnets. The radiation produced grows exponentially in intensity until it reaches a saturation point. We report on the demonstration of self-amplified spontaneous emission gain, exponential growth, and saturation at visible (530 nanometers) and ultraviolet (385 nanometers) wavelengths. Good agreement between theory and simulation indicates that scaling to much shorter wavelengths may be possible. These results confirm the physics behind the self-amplified spontaneous emission process and forward the development of an operational x-ray free-electron laser.

CT differentiation of pneumonic-type bronchioloalveolar cell carcinoma and infectious pneumonia

The objective was to analyse the potential of CT to distinguish pneumonic-type bronchioloalveolar cell carcinoma (BAC) from infectious pneumonia. The study consisted of 21 patients with pathologically proven BAC and 30 patients with infectious pneumonia. Both groups of patients had patchy or diffuse consolidation of more than half the area of a lobe or lobes on CT. CT findings in these two groups were compared with regard to morphological appearance, including CT angiogram, air bronchogram, mucous bronchogram, contrast enhancement pattern, pseudocavitation, cavity with air-fluid level, location, satellite lesion, ground-glass opacity and bulging of the interlobar fissure. Air-filled bronchi were morphologically analysed as dilatation, stretching, sweeping, widening of the branching angle, squeezing and crowding. Lymphadenopathy and pleural effusion were also analysed. CT findings favouring the diagnosis of BAC included an air-filled bronchus within the consolidation with stretching, squeezing, sweeping, widening of the branching angle and bulging of the interlobar fissure (p<0.05). It is concluded that CT may be helpful in differentiating pneumonic-type BAC from infectious pneumonia if the air-filled bronchus within the consolidation shows stretching, squeezing, widening of the branching angle or bulging of the interlobar fissure.

Etk/Bmx activation modulates barrier function in epithelial cells

Etk/Bmx is a member of the Tec family of cytoplasmic non-receptor tyrosine kinases known to express in epithelial cells. We demonstrate herein that Etk activation in stably Etk-transfected epithelial Pa-4 cells resulted in a consistently increased transepithelial resistance (TER). After 24 h of hypoxic (1% O2) exposure, the TER and equivalent active ion transport rate ( I eq) were reduced to <5% of the normoxia control in Pa-4 cells, whereas both TER and I eqwere maintained at comparable and 60% levels, respectively, relative to their normoxic controls in cells with Etk activation. Moreover, Pa-4 cells exhibited an abundant actin stress fiber network with a diffuse distribution of β-catenin at the cell periphery. By contrast, Etk-activated cells displayed a redistribution of actin to an exclusively peripheral network, with a discrete band of β-catenin also concentrated at the cell periphery, and an altered occludin distribution profile. On the basis of these findings, we propose that Etk may be a novel regulator of epithelial junctions during physiological and pathophysiological conditions.

Activated human T cells directly induce osteoclastogenesis from human monocytes: possible role of T cells in bone destruction in rheumatoid arthritis patients

OBJECTIVE

To elucidate the direct role of human T cells in the induction of osteoclastogenesis in rheumatoid arthritis (RA), by studying human monocytes and the pathogenetic roles of receptor activator of nuclear factor kappaB ligand (RANKL), RANK, and osteoprotegerin (OPG).

METHODS

Synovial tissue obtained at total knee replacement was stained immunohistologically using anti-RANKL, CD3, and CD4 antibodies. Synovial fluid was obtained from patients with RA, osteoarthritis (OA), gout, or trauma. Concentrations of the soluble form of RANKL (sRANKL) and OPG in the synovial fluid were measured by enzyme-linked immunosorbent assay. Activated T cells from peripheral blood mononuclear cells (PBMC) of healthy volunteers were cultured with human monocytes from PBMC.

RESULTS

Immunostaining of the synovial tissue of RA patients demonstrated that RANKL-positive cells were detected in a subset of fibroblast-like synoviocytes and infiltrating mononuclear cells. Double immunostaining revealed that RANKL-positive cells were detected in a subset of CD3+ cells and CD4+ cells. An increased concentration of sRANKL and a decreased concentration of OPG were detected in synovial fluid from RA patients. The ratio of the concentration of sRANKL to that of OPG was significantly higher in synovial fluid of RA patients than in synovial fluid of patients with OA or gout. The activated T cells expressing RANKL induced osteoclastogenesis from autologous peripheral monocytes. The role of RANKL in this osteoclastogenetic process was confirmed by dose-dependent inhibition by OPG.

CONCLUSION

The present study is the first to demonstrate osteoclastogenesis using human-derived T cells and monocytes. In addition, the present findings suggest that excess production of RANKL by activated T cells increases the level of sRANKL in synovial fluid and may contribute to osteoclastic bone resorption in RA patients.

Recursive solution for beam dynamics of periodic focusing channels

We present recursive analysis for beam dynamics of periodic focusing channels based on the Fourier coefficients of the focusing function. Formulas for orbit stability and the envelope function are derived. The results should be useful for numerical calculation and for developing analytical understanding of channels employing extended focusing elements. Applications to muon ionization cooling channels are discussed.

Capsid size determination in the P2-P4 bacteriophage system: suppression of sir mutations in P2's capsid gene N by supersid mutations in P4's external scaffold gene sid

The sid gene of the P2-dependent phage P4 provides an external scaffold so P2 N gene encoded protomers assemble as T = 4 capsids rather than as P2's T = 7 capsids. Mutations (sir) in the middle of N interfere with Sid's function. We describe a new P4 mutant class, nms ("supersid") mutations, which direct also P2 sir to provide small capsids. Three different nms mutations were located near the sid end, commingled with sid(-) mutations. Suppression of sir by nms is not allele-specific. Our results favor this interpretation of capsid size control: (i) sir mutations reduce pN protomer flexibility and thereby interfere with the generation of T = 4 compatible hexons; (ii) the C-termini of Sid molecules link up when forming the scaffold; nms mutations strengthen these Sid-Sid contacts and thus allow the scaffold to force even sir-type protomers to form T = 4 compatible hexons. Some related findings concern suppression of N ts mutations by P4.

Isotype-dependent inhibition of tumor growth in vivo by monoclonal antibodies to death receptor 4

To explore an approach for death receptor targeting in cancer, we developed murine mAbs to human death receptor 4 (DR4). The mAb 4H6 (IgG1) competed with Apo2L/TNF-related apoptosis-inducing ligand (DR4's ligand) for binding to DR4, whereas mAb 4G7 (IgG2a) did not. In vitro, both mAbs showed minimal intrinsic apoptosis-inducing activity, but each triggered potent apoptosis upon cross-linking. In a colon tumor nude mouse model in vivo, mAb 4H6 treatment without addition of exogenous linkers induced apoptosis in tumor cells and caused complete tumor regression, whereas mAb 4G7 partially inhibited tumor growth. An IgG2a isotype switch variant of mAb 4H6 was much less effective in vivo than the parent IgG1-4H6, despite similar binding affinities to DR4. The same conclusion was obtained by comparing other IgG1 and IgG2 mAbs to DR4 for their anti-tumor activities in vivo. Thus, the isotype of anti-DR4 mAb may be more important than DR4 binding affinity for tumor elimination in vivo. Anti-DR4 mAbs of the IgG1 isotype may provide a useful tool for investigating the therapeutic potential of death receptor targeting in cancer.

The changes in delivered oxygen fractions using laerdal resuscitator bag with different types of reservoir

One of the disadvantages of the Laerdal resuscitator bag is that it does not deliver a high concentration of oxygen without a reservoir and an appropriate technique of ventilation. With a specific device that is able to compress a resuscitator bag mechanically at a regular volume, ventilator rate, and speed, we evaluated the effects of various factors (the tidal volume, the ventilator rate, the oxygen flow rate, the type of reservoir) of the Laerdal resuscitator bag during positive pressure ventilation that affect the delivered oxygen fraction (FDO2) and also whether 250 mL and 500 mL corrugated tubes could be used as substitutes for the reservoir bag. The 250 mL corrugated tube increased the FDO2 to over 96% with an oxygen flow rate of 15 L/min. The 500 mL corrugated tube increased the FDO2 to over 96% with an oxygen flow rate of 10 L/min regardless of the ventilator rate at a fixed tidal volume of 500 mL. At the identical fixed tidal volume of 500 mL, the 1,600 mL reservoir bag increased the FDO2 to over 92% with an oxygen flow rate of 5 L/min and to over 96% at 7.5 L/min regardless of the ventilator rate. We concluded that the FDO2 of the Laerdal resuscitator bag depends on various factors such as tidal volume, ventilator rate, oxygen flow rate, and type of reservoir and both the 250 mL and 500 mL corrugated tubes can be used as substitutes.

Oral health attitudes/behavior and gingival self-care level of Korean dental hygiene students

The purpose of this study was to examine oral health attitudes/behavior and gingival self-care levels of Korean dental hygiene students (n = 271). A questionnaire known as HU-DBI (Korean version) was administered to each class. Higher scores of the HU-DBI indicate better oral health attitudes/behavior. The student's gingival self-care level was scored as excellent (+2), good (+1), questionable (0), poor (-1), or very poor (-2) according to the criteria of the Oral Rating Index (ORI) for youth. The mean score of the HU-DBI was 6.40, and that of the ORI was +0.12. Most samples scored 0 or +1. The mean HU-DBI scores of year-2 and year-3 students (7.06, and 7.61 respectively) were significantly greater than that of year-1 students (5.23) (P<0.001). Twenty-three percent of the students reported a belief that they may eventually require false teeth. Half stated that they put off going to the dentist until they had toothache. Year-1 students were more likely to have this attitude compared to year-3 students. HU-DBI scores were significantly associated with ORI scores (r = 0.315; P<0.001). The differences in the HU-DBI and ORI scores across the level of education were highly significant.

Palladium(0)-catalyzed carbonylation-coupling-cyclization of allenic sulfonamides with aryl iodides and carbon monoxide

[reaction: see text] alpha-Allenic sulfonamides undergo carbonylation-coupling-endo-cyclization with aryl iodides in the presence of Pd(PPh(3))(4) (5 mol %), K(2)CO(3), and CO (20 atm) to form 3-aroyl-2- or 3-pyrrolines. Alternatively the carbonylation-coupling-exo-cyclization of gamma- and delta-substituted sulfonamides under the same conditions afforded pyrrolidine- or piperidine-substituted enones.

Temporal contrast adaptation in the input and output signals of salamander retinal ganglion cells

We investigated how the light-evoked input and output signals of salamander retinal ganglion cells adapt to changes in temporal contrast, i.e., changes in the depth of the temporal fluctuations in the light intensity about the mean. Increasing the temporal contrast sped the kinetics and reduced the sensitivity of both the light-evoked input currents measured at the ganglion cell soma and the output spike trains of the cell. The decline in sensitivity of the input currents after an increase in contrast had two distinct kinetic components with fast (<2 sec) and slow (>10 sec) time constants. The recovery of sensitivity after a decrease in contrast was dominated by a single component with an intermediate (4-18 sec) time constant. Contrast adaptation differed for on and off cells, with both the kinetics and amplitude of the light-evoked currents of off cells adapting more strongly than those of on cells. Contrast adaptation in the input currents of a ganglion cell, however, was unable to account for the extent of adaptation in the output spike trains of the cell, indicating that mechanisms intrinsic to the ganglion cell contributed. Indeed, when fluctuating currents were injected into a ganglion cell, the sensitivity of spike generation decreased with increased current variance. Pharmacological experiments indicated that adaptation of spike generation to the current variance was attributable to properties of tetrodotoxin-sensitive Na(+) channels.

Stromal cell activity in bone marrow from the tibia and iliac crest of patients with rheumatoid arthritis

Bone marrow aspirates were obtained from the iliac crest and tibial epiphysis in 23 patients with rheumatoid arthritis (RA) who were undergoing total knee arthroplasty. The number of fibroblast colony-forming units (CFU-F), which contain osteogenic precursor cells, and alkaline phosphatase (ALP) activity, as a marker of the osteoblastic phenotype. were compared between the iliac and tibial marrow for each patient. The prevalence of CFU-F in tibial marrow was similar to that in iliac marrow (96% vs 100%, respectively). However, the average number of CFU-F per 4 x 10(5) bone marrow mononuclear cells was significantly lower in tibial marrow than in iliac marrow (8.2 vs 28.1, respectively; P < 0.01). Although ALP activity was detected in all iliac and tibial marrow specimens, it was significantly lower in tibial marrow compared with iliac marrow (3.7 vs 11.9 nmol/min/mg protein, respectively; P < 0.01). In addition, there was a significant correlation between the patient's age and the number of CFU-F in iliac marrow (r = -0.547; P < 0.01), although there was no correlation in tibial marrow. These results demonstrate that the osteogenic activity of bone marrow varies at different sites in patients with RA. The data may also contribute to further investigation into the differential effects of various disease processes on systemic as well as local stromal cell activity in bone marrow.

Survival of conditionally immortalized hepatocytes in the spleen of syngeneic rats

BACKGROUND

Hepatocyte transplantation has been shown to be effective in the treatment of liver failure; however, the shortage of donor organs limits its clinical application. Several reports have suggested that conditionally immortalized hepatocytes (CIH) could be an alternative to primary hepatocytes. However, CIH are known to undergo apoptosis in vitro at a non-permissive temperature, which is similar to body temperature.

METHODS

To investigate the duration of survival and in vivo apoptosis of CIH in the syngeneic host, the L2A2 cells (a kind of CIH) that were established from hepatocytes of a Lewis rat with a gene for a temperature-sensitive Simian Virus 40 (SV40) large T antigen were transplanted into the spleen. Cells were isolated from the spleen that was removed periodically up to 6 months, and used to detect the presence of the L2A2 cells among them with the selective culture for CIH and T-antigen PCR. In situ apoptosis of L2A2 cells was also examined. In order to improve the survival of transplanted L2A2 cells in the host, a group of rats were partially hepatectomized 1 day before transplantation was performed.

RESULTS

The L2A2 cells secreted albumin at a rate of 1.17 +/- 0.18 microg/24 h per 10(6) cells in vitro. After transplantation, L2A2 cell colonies and PCR amplification bands appeared up to 14 and 7 days, respectively, but this duration was not prolonged by a partial hepatectomy. The spleen showed a large number of hepatocytes that were in the process of dying on the 5th day, and only a number of ghost hepatocytes were present on the 7th day of transplantation. No tumors were found during the 6-month observation period.

CONCLUSIONS

Conditionally immortalized hepatocytes can survive in the spleen for a limited period, in spite of the growth stimulation, most likely because they undergo apoptosis in vivo as well as in vitro at a non-permissive temperature. These data suggest that the use of these cells in hepatocyte transplantation be limited to temporary hepatic support.

The incidence and clinical characteristics of symptomatic propylthiouracil-induced hepatic injury in patients with hyperthyroidism: a single-center retrospective study

OBJECTIVES

Although symptomatic propylthiouracil (PTU)-induced hepatic injury is known to be rare, there have been few reports about its exact incidence in patients with hyperthyroidism. We tried to evaluate its incidence in a single center and its clinical course.

METHODS

Medical records of 912 hyperthyroid patients who had been diagnosed between March 1990 and December 1998 were reviewed about clinical characteristics, management, and laboratory findings. Symptomatic PTU-induced hepatic injury was defined as the development of jaundice or hepatitis symptoms with at least a 3-times elevation of liver function tests (LFT) without other causes.

RESULTS

Four hundred ninety-seven patients (age 42.6 +/- 10.7 yr, male/female 140/357) were included. Clinically overt hepatitis developed in six patients (1.2%; age, 43.7 +/- 14.8 yr; male:female ratio, 3:3) between 12 and 49 days after PTU administration. Jaundice and itching developed in five patients, fever in two, rash in two, and arthralgia in one. Bilirubin, ALT, and ALP increased in five, four, and six patients, respectively (293 +/- 288 micromol/L, 143 +/- 111 U/L, and 265 +/- 81 U/L; normal, < 117 U/L). The type of hepatic injury was cholestatic in three, hepatocellular in one, and mixed in two patients. None resulted from viral hepatitis. There were no statistical differences in age, sex, PTU dose, or T4 and T3 levels at initial diagnosis between patients with and without hepatic injury. LFT normalized in all patients between 16 and 145 (72.8 +/- 46.4) days after the PTU withdrawal.

CONCLUSIONS

Symptomatic hepatic injury develops usually within the first few months of PTU administration with rare frequency, but its clinical course is relatively benign once the drug is withdrawn. However, it may be difficult to predict its development, so all patients should be monitored for rise in LFTs at regular intervals, especially during the early period.

Regulation of rat heat shock factor 2 expression during the early organogenic phase of embryogenesis

A central step in the transcriptional regulation of heat shock protein (hsp) genes is the binding of the heat shock factor (HSF) to the upstream heat shock elements (HSEs). In vertebrates, HSF2 has been suggested to mediate the transcriptional regulation of hsp gene expression during development and differentiation. The expression levels of HSF2 were shown to vary widely among fully developed mouse organs. However, there exists limited information on the regulation of HSF2 expression during the inductive stage of organ formation in mammalian development. In this study, we have cloned the rat HSF2 cDNA and examined embryos for HSF2 expression from days 9.5 (E9.5) to 15.5 (E15.5) of gestation that correspond to the period when the major organ primordia are being actively established. We show that rat HSF2 has 94.6 and 96.3% identity to mouse HSF2 in nucleotide and amino acid sequences, respectively. By establishing a competitive RT-PCR, we show that about 503.6 pg of HSF2 mRNA were present per microgram of embryonic RNA in the primitive streak stage E9.5 embryos. The amounts of HSF2 mRNA then gradually decreased, resulting in an approximately 300-fold reduction in E15.5 embryos. The amounts of HSF2 mRNA in the embryos were found to be closely correlated with those of HSF2 protein and their HSE-binding activities. To our knowledge, this is the first detailed report on the structure and regulation of the rat HSF2 during the early organogenic period of mammalian embryogenesis.