Down-regulation of the c-Jun N-terminal kinase (JNK) phosphatase M3/6 and activation of JNK by hydrogen peroxide and pyrrolidine dithiocarbamate

Oxidative stress activates the c-Jun N-terminal kinase (JNK) pathway. However, the exact mechanisms by which reactive oxygen species (ROS) activate JNK are unclear. We found that the ability of hydrogen peroxide (H(2)O(2)) to induce JNK activation varied in different cell types. Pyrrolidine dithiocarbamate (PDTC), a presumed antioxidant, induced JNK activation on its own and enhanced JNK activation by H(2)O(2) in many cell types, including Jurkat, HEK293, and LNCaP and Tsu-Pr1 prostate cancer cells. The activation of JNK by PDTC, in the presence or absence of exogenous H(2)O(2), was dependent on its chelating ability to metal ions, most likely copper ions. Despite the strong JNK-activating ability, H(2)O(2) plus PDTC did not induce significant activation of the upstream kinases, SEK1/MKK4 and MKK7. However, the JNK inactivation rate was slower in cells treated with H(2)O(2) plus PDTC compared with the rate in cells treated with ultraviolet C (UV-C). Treatment of H(2)O(2) plus PDTC significantly decreased the expression levels of a JNK phosphatase, M3/6 (also named hVH-5), but not the levels of other phosphatases (PP2A and PP4). In contrast, UV-C irradiation did not cause the down-regulation of M3/6. These results suggest that JNK activation by H(2)O(2) plus PDTC resulted from the down-regulation of JNK phosphatases. Our data also reveal a necessity to carefully evaluate the pharmacological and biochemical properties of PDTC.

Piloleiomyoma--a report of five cases

Piloleiomyomas are uncommon smooth muscle neoplasms of the skin with a few reproted cases in Indian literature (1,2,3,4,5). They are often misdiagnosed clinically. A correct biopsy report is important because patients may have to be managed medically since surgery is associated with a high rate of recurrence. The classical histologic findings, and Masson's stain to confirm the smooth muscle origin aids in the correct diagnosis.

Effects of dexamethasone treatment on bone and collagen turnover in preterm infants with chronic lung disease

Dexamethasone is used commonly in the treatment of chronic lung disease of prematurity, but there are concerns about possible deleterious effects on growth and bone. Our aim in this study was to examine the effects of dexamethasone treatment on bone and collagen turnover in preterm infants. Bone-specific alkaline phosphatase, the C-terminal propeptide of type I collagen (PICP, reflecting whole-body type I collagen synthesis), and the N-terminal propeptide of type III procollagen (P3NP, reflecting soft tissue collagen turnover), together with the C-terminal telopeptide of type I collagen (ICTP), urinary pyridinoline (Pyd), and deoxypyridinoline (all markers of collagen breakdown) were measured at weekly intervals over the first 12 wk of life in 14 preterm infants with chronic lung disease treated with dexamethasone. Results were expressed as SD scores relative to preterm control infants not treated with dexamethasone. PICP, P3NP, ICTP, and Pyd all showed marked decreases (-2.1 to -3.7 SD scores) during the first week of treatment (p < 0.001), returning to pretreatment levels after stopping dexamethasone. In the group as a whole, these collagen markers were negatively correlated with dexamethasone dose (p < 0.0001); negative correlations were also seen in most individual babies, although the slopes of individual regression lines varied by a factor of 2. Weight gain at 12 wk was correlated with PICP, expressed as the mean SD score over 12 wk for each baby, (r = 0.69, p < 0.01) but not with other markers or cumulative dose of dexamethasone. We conclude that dexamethasone markedly suppressed collagen turnover in preterm infants in a dose-dependent fashion, although some babies were more affected than others. The degree of suppression of type I collagen synthesis was a strong independent predictor of overall weight gain over the first 12 wk of life.

The effect of dexamethasone on growth, mineral balance and bone mineralisation in preterm infants with chronic lung disease

The aim of this prospective longitudinal study was to observe the effects of treatment with dexamethasone on somatic growth, mineral balance and bone mineralisation in very low birth weight (VLBW) preterm infants with chronic lung disease (CLD). Dexamethasone was started at a dose of 500 microg/kg body weight per day for 3 days followed by gradually decreasing doses for a total period of 3 weeks' treatment if the infant was still mechanically ventilated in the 3rd postnatal week and had signs of CLD on the chest radiograph. Eleven infants with CLD treated with dexamethasone were studied. Administration of dexamethasone treatment was associated with significantly (P < 0.05) lower weight velocity, head circumference velocity, lower leg length (measured by the neonatal knemometer) velocity compared to pre-treatment changes. The start of dexamethasone treatment was also associated with a fall in calcium absorption (61% to 41.7%, P < 0.05) calcium retention (60.8% to 40.6%, P < 0.05) and phosphate retention (65% to 39.6%, P < 0.05); phosphate absorption was not significantly affected (88.8% to 92%, P > 0.05). Somatic growth and mineral balance improved during the immediate post-treatment period. Acute disturbances of bone mineral content (measured by dual energy radiographic densitometry), plasma calcium and phosphate were also seen but not reaching statistical significance at the P < 0.05 level.

CONCLUSION

The start of steroids is associated with a rapid and significant fall in growth velocity, calcium absorption and calcium and phosphate retention in infants with chronic lung disease with recovery occurring after completion of steroid treatment.

Surgery for primary supratentorial intracerebral haemorrhage

BACKGROUND

There is considerable international variation in the rate and indications of surgery for primary supratentorial intracerebral haematoma, reflecting the uncertainty about the effects of surgery.

OBJECTIVES

The objective of this review was to assess the effects of surgery plus routine medical management, compared with routine medical management alone, in patients with primary supratentorial intracerebral haematoma.

SEARCH STRATEGY

We searched the Cochrane Stroke Group trials register, Current Opinion in Neurology and Neurosurgery, and Neurosurgical Clinics of North America (1991 to July 1993) and reference lists of articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials of routine medical treatment plus intracranial surgery compared with routine medical treatment, in patients with presumed or confirmed primary supratentorial intracerebral haematoma. Intracranial surgery included craniotomy, stereotactic endoscopic evacuation or stereotactic aspiration.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied the inclusion criteria, assessed trial quality and extracted the data.

MAIN RESULTS

Four trials were included. No trial had blinded outcome assessment. Craniotomy and endoscopic evacuation were analysed separately. Craniotomy showed a non-significant trend towards increased odds of death and dependency among survivors (odds ratio 1.99, 99% confidence interval 0.92 to 4. 31). The result was inconclusive in the two trials with patients confirmed as having primary supratentorial intracerebral haematoma by CT. Endoscopic evacuation was not shown to significantly decrease the odds of death and dependency among survivors in one trial involving 100 patients (odds ratio 0.45, 99% confidence interval 0. 15 to 1.33).

REVIEWER'S CONCLUSIONS

There is not enough evidence to evaluate the effect of craniotomy or stereotactic surgery, or endoscopic evacuation in patients with supratentorial intracerebral haematoma.

Comparative study of risperidone and haloperidol on clinical and psychosocial parameters in treatment of schizophrenia : a randomised open trial

The study compares the efficacy of risperidone and haloperidol in patients of schizophrenia on various clinical and psychosocial parameters.In the present open, comparative study, in patients suffering from schizophrenia (DSM-IV), 50 patients each were randomly treated with risperidone and haloperidol over a period of 1 year. The clinical improvement was judged on PANSS (Positive and Negative Symptom Scale) and CGIS (Clinical Global Impression Scale). The improvement in psychosocial functioning and other areas was judged using a five point scale (0-4). Though the improvement on PANSS was comparable in both the groups except on the general psychopathology subscale, on CGIS a better improvement profile was observed in risperidone group. In the other psychosocial areas such as social functioning, productivity and education a significantly more number of patients showed improvement in risperidone group as compared to haloperidol group. In significantly less number of patients suicidality and rehospitalization was found in risperidone group as compared to haloperidol group.

Th1 and Th2 deviation of myelin-autoreactive T cells by altered peptide ligands is associated with reciprocal regulation of Lck, Fyn, and ZAP-70

Th0 clones recognizing an immunodominant peptide of myelin basic protein (residues 83-99) were derived from patients with multiple sclerosis. We demonstrate that analogue peptides with alanine substitution at Val86 and His88 had a unique partial agonistic property in inducing Th0 -->Th1 and Th0 -->Th2 deviation of the myelin basic protein-reactive T cell clones, respectively. Th0 to Th1 deviation induced by peptide 86V-->A correlated with up-regulation of Fyn and ZAP-70 kinase activities. Conversely, Th0 to Th2 deviation induced by peptide 88H-->A was associated with complete failure to activate Fyn and ZAP-70 kinases. The observed Th1 and Th2 shift also correlated, to a lesser extent, with Lck kinase activity that was down-regulated with Th1 deviation and increased with Th2 deviation in some T cell clones. We demonstrated that the Th1 and Th2 shift induced by the analogue peptides was a reversible process, as the T cell clones previously exposed to either 86V-->A or 88H-->A peptide could revert to an opposite phenotype when rechallenged reciprocally with a different analogue peptide. The study has important implications in our understanding of regulation of TCR-associated tyrosine kinases by altered peptide ligands and its role in cytokine regulation of autoreactive T cells.

VEGI, a new member of the TNF family activates nuclear factor-kappa B and c-Jun N-terminal kinase and modulates cell growth

Recently a new member of the human tumor necrosis factor (TNF) family named as VEGI was reported. However, very little is known about the biological activities displayed by this cytokine. In this report, we show that in myeloid cells VEGI activated the transcription factor kappa B (NF-kappa B) as determined by the electrophoretic mobility shift assay, induced degradation of I kappa B alpha, and nuclear translocation of p65 subunit of NF-kappa B. VEGI also activated NF-kappa B-dependent reporter gene expression. In addition, VEGI activated c-Jun N-terminal kinase. When examined for growth modulatory effects, VEGI inhibited the proliferation of breast carcinoma (MCF-7), epithelial (HeLa), and myeloid (U-937 and ML-1a) tumor cells; and activated caspase-3 leading to PARP cleavage. VEGI-induced cytotoxicity was potentiated by inhibitors of protein synthesis. VEGI also induced proliferation of normal human foreskin fibroblast cells. The activity of VEGI could neither be neutralized by antibodies against TNF, nor could it compete with TNF binding, indicating that the activity of VEGI is not due to TNF and it binds to a distinct receptor. These results suggest that VEGI, a new member of the TNF family, has a signaling pathway similar to TNF and is most likely a multifunctional cytokine.

Bone and collagen markers in preterm infants: relationship with growth and bone mineral content over the first 10 weeks of life

In a longitudinal study of 25 preterm infants, we have examined the relationship of bone-specific alkaline phosphatase (ALP), C-terminal propeptide of type I collagen (PICP), N-terminal propeptide of type III procollagen (P3NP), C-terminal telopeptide of type I collagen, urinary pyridinoline (Pyd) and deoxypyridinoline (Dpd), with rates of gain in weight, length, and lower leg length and with bone mineral content (BMC), all measured at weekly intervals over the first 10 wk of life. Concentrations of all collagen markers were 10-fold higher than in older children. Each marker showed a distinctive pattern of postnatal change, with early increases in PICP and P3NP and decreases in ICTP reflecting postnatal growth. Once markers had reached a plateau during weeks 4-10, P3NP was positively correlated, whereas Pyd and Dpd were negatively correlated with rate of weight gain (r = +0.44, -0.46, and -0.40, respectively, p < 0.05). P3NP was also positively correlated with overall linear growth (r = +0.44, p < 0.05). PICP was strongly correlated with mean BMC (r = +0.63,p < 0.01) and with total BMC attained by the end of the study period (r = +0.81, p < 0.001). Bone ALP was positively correlated with the rate of bone mineral accretion (r = +0.55, p = 0.01). We conclude that the marker of soft-tissue collagen formation, P3NP, is a good marker for overall ponderal and linear growth in preterm infants, whereas the markers of collagen breakdown, Pyd and Dpd, have inverse relationships with weight gain. The osteoblast markers, PICP and bone ALP, seem to be good surrogate markers for bone mineralization in preterm infants. Markers may provide information on whole-body turnover of bone and collagen that is complementary to traditional physical measures of growth and bone mineralization.

Antioxidants differentially regulate activation of nuclear factor-kappa B, activator protein-1, c-jun amino-terminal kinases, and apoptosis induced by tumor necrosis factor: evidence that JNK and NF-kappa B activation are not linked to apoptosis

Tumor necrosis factor (TNF) is known to mediate its signaling through generation of reactive oxygen species (ROS), but the type of TNF signal regulated by ROS and the nature of the ROS species involved are not fully understood. In this report, we investigated the effect of various superoxide radical quenchers--pyrrolidine dithiocarbamate (PDTC), N-acetyl-L-cysteine (NAC), and glutathione (GSH)--an hydroxyl radical quencher (mannitol), and lipid peroxide quenchers--butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA)--on TNF-induced activation of nuclear transcription factors-kappa B (NF-kappa B) and activator protein-1 (AP-1), c-jun amino-terminal kinase (JNK), and apoptosis in human monocytic U937 cells. TNF-induced NF-kappa B activation was inhibited by both superoxide and lipid peroxide quenchers but potentiated by an hydroxyl radical quencher. In contrast, none of the radical quenchers had any significant effect on TNF-induced AP-1 activation. TNF-induced JNK activation, similar to NF-kappa B, was inhibited by both superoxide and lipid peroxide quenchers but potentiated by hydroxyl radical quencher. TNF-induced activation of caspase activity was blocked by all three types of quenchers. TNF cytotoxicity, however, was potentiated by superoxide radical quenchers and suppressed by hydroxyl radical and lipid peroxide quenchers. Overall, these results suggest that hydroxyl radicals mediate TNF-induced apoptosis but not activation of NF-kappa B, AP-1, and JNK; superoxide radicals mediate NF-kappa B and JNK activation but potentiate apoptosis; and lipid peroxides are required for all the signals induced by TNF.

Ectopic expression of hepatitis C virus core protein differentially regulates nuclear transcription factors

The putative core protein of hepatitis C virus (HCV) regulates cellular growth and a number of cellular promoters. To further understand its effect, we investigated the role of the core protein in the endogenous regulation of two distinct transcription factors, nuclear factor-kappaB (NF-kappaB) and activating protein-1 (AP-1), and the related mitogen-activated protein kinase kinase (MAPKK) and c-Jun N-terminal kinase (JNK). Stable cell transfectants expressing the HCV core protein suppressed tumor necrosis factor (TNF)-induced NF-kappaB activation. Supershift analysis revealed that NF-kappaB consists of p50 and p65 subunits. This correlated with inhibition of the degradation of IkappaBalpha, the inhibitory subunit of NF-kappaB. The effect was not specific to TNF, as suppression in core protein-expressing cells was also observed in response to a number of other inflammatory agents known to activate NF-kappaB. In contrast to the effect on NF-kappaB, the HCV core protein constitutively activated AP-1, which correlated with the activation of JNK and MAPKK, which are known to regulate AP-1. These observations indicated that the core protein targets transcription factors known to be involved in the regulation of inflammatory responses and the immune system.

Involvement of Ras and MAP kinase (ERK-1) in cisplatin-induced activation of murine bone marrow-derived macrophages

Cisplatin (cis-diamminedichloroplatinum II), a potent antitumor compound, stimulates immune responses by activating monocytes/macrophages and other cells of the immune system. However, the mechanism by which cisplatin activates these cells is poorly characterised. Our earlier findings indicate that cisplatin treatment stimulates rapid tyrosine phosphorylation in a number of cellular proteins in murine macrophages. This initial tyrosine phosphorylation is an important regulatory mechanism and is followed by activation of several other proteins. In the present study, we report the involvement of other key molecules and the role of tyrosine phosphorylation in their activation in the signaling cascade of cisplatin. We observed the involvement of Ras (a low molecular weight GTP-binding protein) and ERK-1 (a MAP kinase) in this signaling cascade. Cisplatin treatment results in an increase in the expression of both Ras and ERK-1 in a dose-dependent manner, which was dependent upon tyrosine phosphorylation. Genistein a PTK inhibitor inhibited the cisplatin induced expression of Ras and ERK-1. These findings indicate that Ras and ERK-1 are important signaling molecules involved in the tumoricidal activation of macrophages with cisplatin and is dependent on initial tyrosine phosphorylation.

Expression of LFA-1 adhesion molecules on cisplatin-treated macrophages

Appropriately activated mononuclear phagocytes mediate contact-dependent tumoricidal activity. Adhesion structures involved in contact-dependent tumor cytotoxicity have not been defined. The present study was aimed at identifying the adhesion structure involved in the tumoricidal activity of cisplatin-activated murine peritoneal macrophages. Tumor cells of different histological origin were used as targets in a 24-h cytotoxicity assay. Anti-CD18 (LFA-1 beta) substantially inhibited macrophage cytotoxicity whereas anti-LFA-1 alpha marginally inhibited macrophage-mediated cytotoxicity. When combined together, almost complete inhibition of tumoricidal activity was observed. Activated macrophages showed augmented binding to target cells and anti-LFA MAb inhibited the binding of resting and activated macrophages to target cells. Cisplatin augmented the expression of LFA-1 alpha and beta integrins and LPS had no effect as assessed by immunoprecipitation. These results implicate that in cisplatin activated macrophages LFA-1 alpha and beta integrins are important molecules in contact-dependent tumoricidal activity.

Protein kinase C: a potential pathway of macrophage activation with cisplatin

Cisplatin (CP) has been reported to activate murine macrophages to tumoricidal state, however, its mechanism of action is not known. In the present study it is reported that the production of: (a) interleukin-1 (IL-1); (b) tumor necrosis factor (TNF); (c) nitric oxide (NO); and (d) macrophage-mediated cytotoxicity by cisplatin-treated bone marrow-derived macrophages were inhibited by PKC inhibitors H-7 and chelerythrine chloride. Also, it was observed that treatment of macrophages with CP resulted in the translocation of PKC from the cytosol to the membrane fraction. These findings suggest the involvement of PKC in the activation of bone marrow-derived macrophages with cisplatin.

Inhibition of tumor necrosis factor (TNF-alpha)-mediated apoptosis by hepatitis C virus core protein

Hepatitis C virus (HCV) putative core protein has displayed many intriguing biological properties. Since tumor necrosis factor (TNF) plays an important role in controlling viral infection, in this study the effect of the core protein was investigated on the TNF-alpha induced apoptosis of human breast carcinoma cells (MCF7). HCV core protein when expressed inhibited TNF-alpha-induced apoptotic cell death unlike the control MCF7 cells, as determined by cell viability and DNA fragmentation analysis. Additionally, HCV core protein blocked the TNF-induced proteolytic cleavage of the death substrate poly(ADP-ribose) polymerase from its native 116-kDa protein to the characteristic 85-kDa polypeptide. Results from this study suggest that the HCV core protein plays a role in the inhibition of TNF-alpha-mediated cell death. Thus, the ability of core protein to inhibit the TNF-mediated apoptotic signaling pathway may provide a selective advantage for HCV replication, allowing for evasion of host antiviral defense mechanisms.

An orphan receptor tyrosine kinase family whose members serve as nonintegrin collagen receptors

Mammalian cells constantly monitor and respond to a myriad of extracellular signals, often by using cell surface receptors. Two important classes of cell surface receptors include the receptor tyrosine kinases, which recognize peptide growth factors such as insulin, and the integrins, which most often mediate binding to components of the extracellular matrix. We report that the collagens serve as ligands for the previously orphan family of discoidin domain-containing receptor-like tyrosine kinases. The unexpected realization that an extracellular matrix molecule can directly serve as a ligand for receptor tyrosine kinases provides an example of ligands shared by integrins and receptor tyrosine kinases, and this finding seems likely to change prevailing views about the mechanisms by which cells perceive and respond to the extracellular matrix.

Cisplatin-induced activation of murine bone marrow-derived macrophages require protein tyrosine phosphorylation

The aim of the present study is to evaluate the involvement of tyrosine phosphorylation in the signal transduction mechanism of cisplatin-induced macrophage activation in vitro. Stimulation of bone marrow-derived macrophages (BMDM) with cisplatin (CP) resulted in a time- and dose-dependent phosphorylation of several proteins having estimated molecular weights of approximately 18, 20, 21, 30, 33, 35, 39, 41, 44, 58 and 123 kD, detected by immunoblot using anti-phosphotyrosine antibody. CP-induced tyrosine phosphorylation was inhibited by the tyrosine kinase inhibitor genistein. Using this inhibitor, we were able to correlate tyrosine phosphorylation with several functional effects of CP on murine bone marrow-derived macrophages (BMDM). Treatment of macrophages with genistein before incubation with CP completely inhibited the CP-induced tumoricidal activation of macrophages as well as production of TNF and NO, whereas pre-treatment of macrophages with phosphatase inhibitor sodium vanadate upregulated macrophage activation in addition to enhanced protein tyrosine phosphorylation. Taken together, these data suggest that tyrosine phosphorylation play a critical regulatory role in the activation of macrophages with CP.

Cisplatin-stimulated murine bone marrow-derived macrophages secrete oncostatin M

Cisplatin (CP), a widely used anticancer drug activates cells of the immune system to a tumoricidal state, and thus functions as a potent biological response modifier. Expression of oncostatin M (OSM), a novel cytokine having a growth regulatory effect, was studied in bone marrow-derived macrophages treated with cisplatin. Supernatants from CP-stimulated macrophages were found to be cytostatic for OSM-sensitive A375 melanoma cells. Immunoblot analysis with anti-OSM antibody revealed that expression of OSM in macrophages upon CP stimulation is a rapid process and within 30 min of CP treatment, a significant amount of OSM is secreted into the culture supernatant. These results therefore indicate that CP can stimulate murine bone marrow-derived macrophages to produce OSM which can be implicated as one of the cytostatic/ cytocidal factors in the antitumour action of cisplatin-stimulated macrophages.

SIDS: parental awareness and infant care practices in contrasting socioeconomic areas in Cardiff

Parental awareness of risk factors for sudden infant death syndrome (SIDS) and infant care practices were compared in an area of relative deprivation and one of relative affluence in Cardiff. Awareness was high in both areas. More infants slept on the side in the deprived area (p < 0.02). One in three babies was exposed to cigarette smoking, significantly more in the deprived area (p < 0.001). Health professionals should discourage side sleeping and smoking, especially in areas of deprivation.

Antitumor activity studies of newly synthesized N-salicyloyl-N'-(p-hydroxybenzthioyl)hydrazine and its copper(II) complex both in vivo and in vitro

A new ligand N-salicyloyl-N'-(p-hydroxybenzthioyl) hydrazine (H2STPH) and its Cu(II) complex [Cu(SPTH)] were prepared and characterized by analytical and physicochemical studies. In vivo antitumor activity of [Cu(STPH)] has been tested against breast tumor in C3H/J strain mice and in vitro on P-815 (murine mastocytoma) and K-562 (human erythroleukemia) cells. LD50 values were estimated at a dose level of 100 mg/kg body weight and a light microscopic study also carried out.

Activation of P388D1 macrophage cell line by chemotherapeutic drugs

It has been found that certain antineoplastic drugs impart their function with a distinct duality. Besides being tumoricidal, they are capable of acting as immunopotentiator. This led us to investigate the effect of cytosine arabinoside (CA), vincristine sulphate (VS), cyclophosphamide (CS), mitomycin C (MMC), hydroxy urea (HU) and lipopolysaccharide (LPS) on a macrophage cell line P388D1. Supernatants collected from P388D1 cells treated with CA, VS, CS, MMC, HU or LPS demonstrated enhanced production of tumor necrosis factor (TNF) confirmed by bioassay on L929 tumor target cells and increased interleukin-1 (IL-1) production by standard thymocyte proliferation bioassay. Also, supernatants showed increased amounts of nitric oxide and lysozyme using Griess reaction and reduction in turbidity of Micrococcus lysodeikticus, respectively. The above findings demonstrate that these drugs may be used not only as chemotherapeutic agents but also as macrophage-activating agents.

YY1 and c-Myc associate in vivo in a manner that depends on c-Myc levels

The c-Myc oncoprotein has previously been shown to associate with transcription regulator YY1 and to inhibit its activity. We show herein that endogenous c-Myc and YY1 associate in vivo and that changes in c-Myc levels, which accompany mitogenic stimulation or differentiation of cultured cells, affect the ratio of free to c-Myc-associated YY1. We have also investigated the mechanism by which association with c-Myc inhibits YY1's ability to regulate transcription. c-Myc does not block binding of YY1 to DNA. However, protein association studies suggest that c-Myc interferes with the ability of YY1 to contact basal transcription proteins TATA-binding protein and TFIIB.

Biochemical markers of bone turnover

Three studies to evaluate procollagen type I C-terminal propeptide, type I collagen cross-linked telopeptide and bone alkaline phosphatase (BALP) in the assessment of bone turnover and growth in children are presented. (1) In 50 short normal children treated with placebo or growth hormone, delta BALP after 3 months of treatment was highly correlated with height velocity response after 1 year (r = 0.67, p < 0.0001). (2) In 12 children with acute lymphoblastic leukaemia, marked changes in collagen peptides, BALP, and lower leg length velocity were seen during the first 6 months of chemotherapy. Suppression occurred during induction and the two intensification phases, with catch-up during the intervening phase (paired t-tests, p < 0.001). (3) Fourteen babies (birthweight < 1,500 g) treated with high-dose dexamethasone for bronchopulmonary dysplasia were compared with 25 non-steroid-treated babies < 1,500 g. Both collagen peptides decreased rapidly and dramatically (mean decreases 41-68%) after dexamethasone was started, accompanied by weight loss and lower leg shrinkage and followed by recovery during steroid weaning.

Cisplatin stimulates protein tyrosine phosphorylation in macrophages

Cisplatin [cis-dichlorodiamine platinum (II)], a potent anti-tumor compound, stimulates immune responses by activating monocyte-macrophages and other cells of the immune system. The mechanism by which cisplatin activates these cells is poorly characterized. Since protein tyrosine phosphorylation appears to be a major intracellular signalling event that mediates cellular responses, we examined whether cisplatin alters tyrosine phosphorylation in macrophages. We found that cisplatin increased tyrosine phosphorylation of several proteins in peritoneal macrophages and in P388D1 and IC-21 macrophage cell lines. Treatment of macrophages with tyrosine kinase inhibitors, genestein and lavendustin A, inhibited cisplatin-stimulated protein tyrosine phosphorylation in macrophages. Macrophages treated with cisplatin also exhibit increased fluorescence with anti-phosphotyrosine-FITC antibody. These data indicate that protein tyrosine phosphorylation plays a role in cisplatin-induced activation of macrophages.

Induction of protein tyrosine phosphorylation in macrophages incubated with tumor cells

The cellular and molecular interaction between monocyte/macrophage and tumor cells leading to macrophage activation is not clearly understood. Since protein tyrosine phosphorylation appears to be a major intracellular signalling event, we checked whether the tumor cells alter tyrosine phosphorylation of proteins in macrophages. We found that both L929 and Yac-1 tumor cells induced increased tyrosine phosphorylation of several polypeptides in peritoneal as well as P388D-1 and IC-21 macrophages. Macrophages co-cultured with tumor cells also showed increased fluorescence with anti-phosphotyrosine-FITC antibody. These observations suggest that increased tyrosine phosphorylation plays a role in tumor cell-induced activation of macrophages.

The basic helix-loop-helix-zipper domain of TFE3 mediates enhancer-promoter interaction

Binding sites for three families of sequence-specific DNA-binding proteins, microE3, C/EBP, and OCT, are found in both the promoters and the intronic enhancer of the immunoglobulin heavy-chain gene. We have used a cotransfection system to investigate how proteins binding these sites may participate in enhancer-promoter interactions. Basic helix-loop-helix-zipper (BHLHZIP) proteins TFE3 and TFEB activate from a distance in this assay, but the basic zipper (BZIP) protein NF-IL6 and endogenous OCT-binding proteins do not. Our results suggest that remotely bound TFE3 is recruited to the initiation site by association with proximally bound TFE3; this interaction is mediated by the BHLHZIP domain and not by activation domains of TFE3. The BZIP domain of Ig/EBP lacks this activity, revealing an important functional difference between these structurally related dimerization domains. We also show that TFE3 can exist as a tetramer in solution and that tetramerization is determined by the HLHZIP domain. These data support a model in which protein-protein interactions between proximally and remotely bound TFE3 recruit TFE3 to the initiation site for activation. The IgH gene is the first example of a cellular gene in which proximal and distal binding sites are found for a protein capable of mediating enhancer-promoter interaction.

Inhibition of transcriptional regulator Yin-Yang-1 by association with c-Myc

Yin-Yang-1 (YY1) regulates the transcription of many genes, including the oncogenes c-fos and c-myc. Depending on the context, YY1 acts as a transcriptional repressor, a transcriptional activator, or a transcriptional initiator. The yeast two-hybrid system was used to screen a human complementary DNA (cDNA) library for proteins that associate with YY1, and a c-myc cDNA was isolated. Affinity chromatography confirmed that YY1 associates with c-Myc but not with Max. In cotransfections, c-Myc inhibits both the repressor and the activator functions of YY1, which suggests that one way c-Myc acts is by modulating the activity of YY1.

Urological injuries during obstetric and gynaecological surgical procedures

Urological injuries during obstetric and gynaecological operations carried out between Jan. '88 to Dec. '88, at a hospital involved in resident teaching programmes were analysed retrospectively. Each case was reviewed for predisposing factors, location and type of injury, time and method of recognition and management. Fifteen injuries were documented in 892 gynaecological procedures and 296 obstetric procedures. Twelve injuries occurred during gynaecological operations whereas 3 occurred during obstetric operations. Thirteen were bladder injuries and two were ureteric injuries. Infiltrating carcinoma of cervix, pelvic adhesions, adhesions because of previous operations and distorted anatomy, were the important risk factors.

Cardiac conducting system of Gallus domesticus with special reference to the atrial bundles

Gross anatomy and histology of the cardiac conducting system of Gallus domesticus has been studied. Detailed histology of the atrium revealed for the first time, in the avian heart, the presence of three atrial bundles which communicate between the sinuatrial node and the atrioventricular node. Purkinje fibres in the subendocardium of the right atrium are observed. An atrioventricular segment comprising of the posterior end of the interatrial septum and the atrioventricular nodal region has been reported in which the three atrial bundles converge. The role of the atrial bundles in the cardiac contraction has been discussed.