Requirement for integration of phorbol 12-myristate 13-acetate and calcium pathways is preserved in the transactivation domain of NFAT1

The transcription factor NFAT integrates signals from both calcium- and phorbol ester-stimulated signaling pathways. The calcium signal activates the calmodulin (CaM)-dependent phosphatase calcineurin, which dephosphorylates the regulatory domain of NFAT and promotes its nuclear import, while the phorbol ester signal results in synthesis and activation of Fos and Jun, transcription factors that bind cooperatively with the NFAT DNA-binding domain in the nucleus to mediate the transcription of many target genes. Here we show that transactivation by a GAL4 fusion protein containing the strong acidic N-terminal transactivation domain (TAD) of NFAT1 also requires both calcium and phorbol ester stimulation. The calcium requirement can be mimicked by coexpression of activated versions of two CaM-dependent enzymes, calcineurin and CaM kinase IV. Our data indicate that a 144-amino acid segment of NFAT1, containing the N-terminal TAD but lacking the DNA-binding and Fos/Jun interaction domains, resembles the full-length protein in requiring a combined input from two separate signaling pathways for optimal function in cells.

The duration of nuclear residence of NFAT determines the pattern of cytokine expression in human SCID T cells

The expression of cytokine genes and other inducible genes is crucially dependent on the pattern and duration of signal transduction events that activate transcription factor binding to DNA. Two infant patients with SCID and a severe defect in T cell activation displayed an aberrant regulation of the transcription factor NFAT. Whereas the expression levels of the NFAT family members NFAT1, -2, and -4 were normal in the patients' T cells, dephosphorylation and nuclear translocation of these NFAT proteins occurred very transiently and incompletely upon stimulation. Only after inhibition of nuclear export with leptomycin B were we able to demonstrate a modest degree of nuclear translocation in the patients' T cells. This transient activation of NFAT was not sufficient to induce the expression of several cytokines, including IL-2, IL-3, IL-4, and IFN-gamma, whereas mRNA levels for macrophage inflammatory protein-1alpha, GM-CSF, and IL-13 were only moderately reduced. By limiting the time of NFAT activation in normal control cells using the calcineurin inhibitor cyclosporin A, we were able to mimic the cytokine expression pattern in SCID T cells, suggesting that the expression of different cytokine genes is differentially regulated by the duration of NFAT residence in the nucleus.

Liver transplantation in patients with transjugular intrahepatic portosystemic shunts

BACKGROUND

In patients with intractable oesophageal variceal bleeding, transjugular intrahepatic portosystemic shunts (TIPSS) are being used increasingly as a bridge to orthotopic liver transplantation (OLTx). There is little information in the literature concerning variations in the operative techniques of OLTx required because of the presence of TIPSS.

METHODS

A retrospective review of patients treated by TIPSS prior to OLTx was undertaken. The aims were to assess the effectiveness of TIPSS in bridging patients to OLTx and to examine whether TIPSS influence the operative management of OLTx.

RESULTS

Over a 4-year period eight adult patients underwent TIPSS insertion prior to OLTx in the Australian National Liver Transplant Unit (ANLTU). Transplantation was performed at a mean of 14.6 (0.3-53.8) months after TIPSS insertion. Prevention of major recurrent variceal haemorrhage prior to transplantation was achieved in six cases. In two patients the stents were predominantly intrahepatic and they did not interfere with OLTx. In five patients the stents extended into the portal vein, requiring removal during OLTx either by division of the stent with the recipient portal vein, followed by removal of the fractured stent wires from the portal veins (n = 3), or by 'endarterectomy' of the recipient portal vein, allowing removal of the intact stent (n = 2). In one case where the stent extended into the suprahepatic inferior vena cava, removal was achieved by traction without difficulty. All patients are alive at a mean of 24 (7-53) months post-transplant and none has portal vein abnormalities. When compared to 178 adult patients who had no TIPSS and underwent primary OLTx during the same study period, there was no difference in the length of operating time or the usage of blood products during OLTx.

CONCLUSION

Transjugular intrahepatic portosystemic shunts offer a bridge to OLTx by providing effective control of variceal haemorrhage. In the present series TIPSS did not increase surgical morbidity or mortality, but emphasis is placed upon the need for optimal TIPSS placement within the liver to facilitate subsequent OLTx.

Recent perspectives in the design of antiasthmatic agents

Asthma is a common respiratory disorder. It can no longer be viewed as a reversible airway obstruction but should instead be considered primarily as an inflammatory illness that has bronchial hyperreactivity and bronchospasm as its result. There are several potential benefits as well as limitations of the currently available antiasthmatic agents such as anticholinergics, beta 2-selective agonists, methylxanthines, corticosteroids, or mast cell stabilizers. Recent trends in the design of new antiasthmatic agents include isozyme selective phosphodiesterase inhibitors, inhibitors of the biosynthesis of interleukin-4 and IL-4 antagonists, lipoxygenase and leukotriene inhibitors, thromboxane A2 receptor antagonists, potassium channel openers and monoclonal antibodies.

Role of antioxidant enzymes in brain tumours

Erythrocyte antioxidant enzymes were analysed in 100 patients with intracranial neoplasm and in 47 controls. There was a significant decrease in RBC glutathione reductase (GRx) and superoxide dismutase (SOD) activity in most types of brain tumor cases. Patients with acoustic neurinoma showed a significant reduction in selenium-dependent glutathione peroxidase (Se-GPx) activity. A decrease in catalase (CT) activity was seen in most of the brain tumor patients but remained statistically insignificant when compared to controls. A significant increase in plasma ceruloplasmin concentration was observed in patients with glioma. These enzymes were also studied in 27 post-treatment cases. GRx activity returned to normal levels in these patients. RBC SOD and plasma ceruloplasmin levels showed a tendency to return to normal. Hence, a marked decrease in the antioxidant enzymes may have a role in the genesis of considerable oxidative stress in patients with brain tumors.

Cell-type-restricted binding of the transcription factor NFAT to a distal IL-4 enhancer in vivo

By DNase I hypersensitivity analysis, we have identified an inducible, cyclosporin A-sensitive enhancer located 3' of the interleukin-4 (IL-4) gene. The enhancer binds the Th2-specific transcription factor GATA3 in vivo but is not perceptibly influenced by the absence of a second Th2-specific factor, cMaf. The antigen-inducible transcription factor NFAT1 binds the IL-4 enhancer and the IL-4 promoter only in stimulated Th2 cells; conversely, NFAT1 binds to the interferon (IFN)-gamma promoter only in stimulated Th1 cells. Our results support a model whereby transcription factors such as NFAT1, which are nonselectively induced in antigen-stimulated T cells, gain access to cytokine regulatory regions only in the appropriate subset of differentiated T cells in vivo. This restricted access enables antigen-dependent and subset-specific transcription of cytokine genes.

Chemomodulatory action of Aloe vera on the profiles of enzymes associated with carcinogen metabolism and antioxidant status regulation in mice

The effect of two doses (30 microl and 60 microl/day/mice daily for 14 days) of the fresh leaf pulp extract of Aloe vera was examined on carcinogen-metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione content, lactate dehydrogenase and lipid peroxidation in the liver of mice. The modulatory effect of the pulp extract was also examined on extrahepatic organs (lung, kidney and forestomach) for the activities of glutathione S-transferase, DT-diophorase, superoxide dismutase and catalase. The positive control mice were treated with butylated hydroxyanisole (BHA). Significant increases in the levels of acid soluble sulfhydryl (-SH) content, NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase, glutathione S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX) and glutathione reductase (GR) were observed in the liver. Aloe vera significantly reduced the levels of cytochrome P450 and cytochrome b5. Thus, Aloe vera is clearly an inducer of phase-II enzyme system. Treatment with both doses of Aloe caused a decrease in malondialdehyde (MDA) formation and the activity of lactate dehydrogenase in the liver, suggesting its role in protection against prooxidant-induced membrane and cellular damage. The microsomal and cytosolic protein was significantly enhanced by Aloe vera, indicating the possibility of its involvement in the induction of protein synthesis. BHA, an antioxidant compound, provided the authenticity of our assay protocol and response of animals against modulator. The pulp extract was effective in inducing GST, DTD, SOD and catalase as measured in extrahepatic organs. Thus, besides liver, other organs (lung, kidney and forestomach) were also influenced favorably by Aloe vera in order to detoxify reactive metabolites, including chemical carcinogens and drugs.

A simple and cost-effective method for preparing DNA from the hard tooth tissue, and its use in polymerase chain reaction amplification of amelogenin gene segment for sex determination in an Indian population

The use of teeth as an important resource in the analysis of forensic case history by polymerase chain reaction (PCR) or other related methods has been reported. However, a major drawback in using teeth has been that the DNA is present only in trace amounts, and the methods to recover DNA from the flinty material have not been efficient or cost effective. In this report, we describe a method to prepare DNA from the hard tooth tissues. Our studies show that ultrasonication of teeth samples yields sufficient amounts of good quality DNA useful for PCR-based diagnostic methods. The teeth could serve as a reliable source of DNA for amplification-based forensic methods in sex determination. DNA could be obtained from any tooth, regardless of the age of subject. Furthermore, by using the AMEL gene-based primers in PCR, we have shown that the AMEL gene serves as a good marker for sex determination in the Indian population. In our study, the PCR-based method was sensitive and proved to be successful for sex determination with a complete specificity.

Long-term alterations in adiposity affect the expression of melanin-concentrating hormone and enkephalin but not proopiomelanocortin in the hypothalamus of ovariectomized ewes

We have developed a ruminant model to study long-term alterations in adiposity on the expression of appetite-regulating peptides in the hypothalamus. In this model endocrine and metabolic status are fully defined as well as body composition. The current study sought to define the effects of altered adiposity on the expression of genes for neuropeptide Y (NPY), POMC, enkephalin (ENK), and melanin-concentrating hormone (MCH). Ovariectomized ewes with high (60 +/- 1 kg) (FAT) or low (37 +/- 3 kg) body weights (THIN) were blood sampled every 10 min for 8 h to determine metabolic and endocrine status. The animals were then killed and the brains perfused for in situ hybridization. Body composition analysis was performed on the carcass using dual energy x-ray absorptiometry; this indicated that the FAT animals were 36 +/- 1% fat, whereas the THIN animals were 15 +/- 2% fat. The LH interpulse interval was lower and mean GH concentrations were higher in the THIN animals; cortisol and TSH levels were not different between the two groups but free T4 and free T3 levels were lower; the FT3:FT4 ratio was higher in THIN ewes. Levels of insulin, lactate, and nonesterified fatty acids were lower in the THIN group, and plasma glucose and urea concentrations were similar in THIN and FAT animals. Levels of gene expression of NPY and MCH were higher in THIN ewes. POMC expression was similar in the two groups. In the THIN animals, ENK expression was lower in the paraventricular and ventromedial nuclei but higher in the periventricular region. In conclusion, we have shown that alterations in adiposity influence the expression of appetite-regulating peptides in the absence of ovarian steroids. The appetite stimulators, NPY and MCH, appear to be involved in the metabolic response to altered adiposity, whereas ENK in the periventricular region may be linked to the secretion of GH and possibly LH. Our results suggest that altered expression of appetite- regulating peptides can be linked with the endocrine and metabolic adaptations that occur with long-term changes in adiposity.

Screening methods for antiasthmatic agents

Bronchial asthma is characterized by both bronchoconstriction and airway inflammation which leads to bronchial hyperresponsiveness to various stimuli. Different mediators are implicated in asthma. As the precise etiology is not known and multiple biochemical processes are triggered by different causative factors, it is difficult to have a single drug which can effectively and simultaneously act upon different mediators. This led to an intense search for potent and safe antiasthmatic drugs. This review intends to compile different screening methods for the evaluation of new candidate drugs with potential for the treatment of asthma. These include in vitro, in vivo, receptor binding and enzymatic methods. Detailed experimental methods have been included with appropriate literature citations.

Uninterrupted moderately accelerated radiotherapy in the treatment of unresectable/advanced head and neck cancer: one institution's experience and a comparative review

Conventional radiotherapy alone in treatment of unresectable or locally advanced head and neck cancer has poor results. To improve outcome without significant increase in acute and late morbidity, we began a moderately accelerated hyperfractionation radiation therapy protocol without breaks for treatment of unresectable/advanced head and neck malignancies. From August 1984 to June 1995, 48 patients with unresectable or advanced carcinoma of the head and neck were treated using a protocol of accelerated hyperfractionation radiation therapy at Kaiser Permanente Medical Center, Los Angeles. Patients were treated twice a day using 150 cGy per fraction, 4 days per week, to a final dose of 60 Gy. Two patients were excluded from this analysis because they did not complete treatment. With a median follow-up of 33 months, 31 (67%) patients have had disease recurrence, 30 (65%) of whom had a locoregional component to their failures. At the last follow-up, 12 patients (26%) were alive with no evidence of disease, 30 patients had died of disease, and 4 had died of intercurrent disease without recurrence. Nine (19%) patients required treatment interruptions averaging 8 days in duration. This accelerated regimen resulted in outcomes similar to those with conventional radiotherapy, most likely because of a conservative total dose. Further refinement of fractionation schedules with potential incorporation of chemotherapy must be investigated.

Rapid, simple and sensitive high-performance liquid chromatographic method for detection and determination of acyclovir in human plasma and its use in bioavailability studies

A rapid, simple and sensitive reversed-phase high-performance liquid chromatographic (HPLC) method has been developed for the measurement of acyclovir concentrations in human plasma and its use in bioavailability studies is evaluated. Unchanged acyclovir has been quantified without the introduction of an internal standard using the present method. Human plasma proteins were selectively precipitated by the addition of 7% perchloric acid to spiked plasma samples or to the plasma samples obtained after acyclovir administration to human volunteers and the mixture was spun at 1000 g for 10 min. The supernatant was directly injected into a Novaflex C18 column and detected at 254 nm. The mobile phase consisted of octane sulfonic acid buffer (pH 2.5) and methanol (92:08). The limit of quantitation for acyclovir in plasma was 20 ng/ml, which enabled the determination of the area under the curve (AUC) more precisely, that is, it is much closer to its extrapolated value. The present method has been successfully applied to samples from bioavailability studies.

Fatal pulmonary embolism: a study of genetic and acquired factors

BACKGROUND

Investigators speculate that hereditary thrombotic disease coupled with acquired factors account for a large number of pulmonary thromboemboli. Clinical correlation between genetic and acquired factors with fatal pulmonary thromboemboli has not been extensively studied.

METHODS

Archival autopsy material was obtained from patients who died of or with pulmonary emboli for whom confirmed autopsy results were available. Polymerase chain reaction-restriction fragment length polymorphism analysis was performed for factor V Leiden and factor II/20210A allele. Retrospective chart review was performed to determine the presence or absence of acquired factors that can predispose to pulmonary thromboemboli.

RESULTS

Two of 36 patients (5.5%) were heterozygous for factor V Leiden. No patients had detected abnormalities for factor II/20210A allele. Eight patients (22.2%) had a malignancy present, one of whom was heterozygous for factor V Leiden. Fourteen patients (38.8%) had recent major surgery or were immobilized.

CONCLUSIONS

The incidence of factor V Leiden and factor II/20210A allele in patients with fatal pulmonary thromboemboli is not greater than published results of the incidence of these factors in the general population. Recognized acquired factors such as malignancy, recent surgery, and immobilization are frequently present in these patients. Our results suggest that genetic profiling of thrombotic disease will not replace clinical vigilance in reducing the risk for death from pulmonary thromboemboli.

Polycystic disease: a rare indication for combined liver and kidney transplantation

We report on a 52-year-old woman who presented with polycystic disease. Both of her kidneys had been removed and she had undergone one failed kidney transplantation. She had severe symptoms from the polycystic liver. The diseased liver and kidney were both treated successfully by performing a combined liver and kidney transplantation.

Femoral head disintegration in a paraplegic patient: loose bodies in neuropathic joints

A case report of potential loose body formation in a hip joint of a paraplegic patient is presented. The case is used to discuss why loose bodies do not persist in neuropathic joints, although they might be expected to be common when this type of joint pathology exists.

Translocation (8;13)(q24.2;q33) in a malignant rhabdoid tumor of the liver

A case of malignant rhabdoid tumor of the liver associated with hypercalcemia of malignancy was studied. The karyotype of the liver primary was 46,XY,t(8;13)(q24.2;q33)[7]/46,XY[13], and of the brain metastasis 46,XY,t(8;13)(q24;q33)[5]/46,XY,t(7;13)(p14;q22) [3]/46,XY,t(1;2;3)(q25;q21;p21) [2]/46,XY[13], respectively. Band 8q24 was previously reported to be rearranged in two malignant rhabdoid tumors, one renal and one hepatic.

Molecular aspects of T-cell differentiation

Differentiated T helper 1 (Th1) and T helper 2 (Th2) T-cells show striking differences in their patterns of cytokine expression. This process is initiated by stimulation with antigen and the cytokines IL-12 and IL-4, respectively, and requires antigen-induced transcription factors such as NFAT and cytokine-induced transcription factors such as STAT4, induced by IL-12, and STAT6, induced by IL-4. This results in induction and maintained expression of subset-specific transcription factors including T-bet in Th1 cells and GATA3 in Th2 cells, which are involved in ensuring the commitment of T-cells to Th1 or Th2 lineages. Here we review the signalling pathways and transcription factors that mediate T-cell differentiation, and describe the epigenetic changes in chromatin structure, locus accessibility and DNA methylation that are known to accompany this process.

An active liver transplant programme for hepatocellular carcinoma in cirrhotic patients: is it justified?

Even at an early stage, hepatocellular carcinoma (HCC) in patients with cirrhosis is often deemed unresectable because of limited liver reserve. In these circumstances, liver transplantation (LTx) offers some hope for palliation or cure. The results of LTx for selected cirrhotic patients with HCC were analysed. The outcomes were compared with those of patients who underwent LTx for other forms of hepatic malignancy and those who underwent LTx for non-malignant conditions. Four hundred and eighty LTx were performed in 441 patients between January 1986 and December 1998. Twenty-eight LTx recipients (25 males, 3 females) of mean age 51 (14 63) yr had cirrhosis and HCC. Twenty-seven patients had underlying predisposing conditions (11 had hepatitis B, 10 had hepatitis C, 2 had hepatitis B and C, 1 had haemochromatosis, 1 had autoimmune hepatitis, 1 had alcoholic cirrhosis and 1 had alpha-1 antitrypsin deficiency). In 22 patients, HCC was diagnosed pre-LTx, and in 6 patients, the cancers were discovered incidentally. The average tumour size and number were 2.8 (0.4-11.5) cm and 1.3 (1-4), respectively. Two patients with known HCC died during and shortly after the LTx operation. Of the other patients, 3 died; 1 died of HCC recurrence 18 months post-LTx, 1 died of graft failure from recurrent hepatitis C and 1 died of fungal sepsis. Twenty-three (82%) patients survived to 22.5 (0.5-96) months post-LTx without HCC recurrence and with 1- and 3-yr actuarial patient survival rates of 87 and 76%, respectively. Equivalent survival rates of patients who underwent LTx for other malignancies (n = 11) were 82 and 46% (p = NS), and for those who underwent LTx for benign causes (n = 402), they were 77 and 73% (p = NS). All 15 patients with known HCC, who met the selection criteria now in use, survived. LTx can result in prolonged. cancer-free survival in a good proportion of patients with cirrhosis and HCC, particularly when the cancers are incidental, or when diagnosed pre-LTx, conforming to established selection criteria. An active LTx programme for this group of patients is justified.

Clinical pharmacokinetics of the CD19 receptor-directed tyrosine kinase inhibitor B43-Genistein in patients with B-lineage lymphoid malignancies

The authors examined the pharmacokinetics of the CD19 receptor-directed tyrosine kinase inhibitor B43-Genistein in 17 patients (4 children, 13 adults) with B-lineage lymphoid malignancies, including 12 patients with acute lymphoblastic leukemia (ALL) and 5 patients with non-Hodgkin's lymphoma (NHL). The immunoconjugate was administered intravenously as a 1-hour continuous infusion at a dose level of either 0.1 mg/kg (N = 12) or 0.18 mg/kg (N = 5), and the plasma concentration-time data were modeled by using the WinNonlin program to estimate the pharmacokinetic parameters. Pharmacokinetic analyses revealed a plasma half-life of 19 +/- 4 hours, mean residence time of 22 +/- 4 hours, and a systemic clearance of 18 +/- 2 mL/h/kg. The average (mean +/- SEM) values for the maximum plasma concentration Cmax, volume of distribution at steady state (Vss), and area under curve (AUC) were 1092 +/- 225 ng/ml, 291 +/- 37 mL/kg, and 9987 +/- 2021 micrograms x h/L, respectively. The AUC values were higher at the 0.18 mg/kg dose level than at the 0.1 mg/kg dose level (16,848 +/- 5118 micrograms x h/L vs. 7128 +/- 1156 micrograms x h/L, p = 0.009). Patients with ALL had a significantly larger volume of distribution at steady state (332 +/- 47 mL/kg vs. 191 +/- 12 mL/kg, p = 0.04), faster clearance (21 +/- 3 mL/h/kg vs. 11 +/- 2 mL/h/kg, p = 0.03), and lower dose-corrected AUC than patients with NHL (6010 +/- 836 micrograms x h/L vs. 12,044 +/- 2707 micrograms x h/L, p = 0.006). There was a trend toward faster clearance rates (23 +/- 4 mL/h/kg vs. 16 +/- 3 mL/h/kg, p = 0.1), shorter elimination half-lives (5.7 +/- 3.6 hours vs. 13 +/- 8.8 hours, p = 0.1), and shorter mean residence times (11 +/- 3 hours vs. 25 +/- 5 hours, p = 0.08) for non-Caucasian patients as compared to Caucasian patients. When compared to adult patients, pediatric patients showed a significantly larger volume of distribution at steady state (418 +/- 82 mL/kg vs. 252 +/- 34 mL/kg, p = 0.02) and a longer elimination half-lives (18.4 +/- 13.6 hours vs. 8.7 +/- 6.7 hours, p = 0.04). The pharmacokinetics of B43-Genistein was not affected by the gender of the patients or by bone marrow transplantation in past medical history. Overall, B43-Genistein showed favorable pharmacokinetics in this heavily pretreated leukemia/lymphoma patient population, which is reminiscent of its recently reported favorable pharmacokinetics in cynomolgus monkeys. To our knowledge, this is the first clinical pharmacokinetics study of a tyrosine kinase inhibitor containing immunoconjugate.