Insulin-like growth factor binding protein-3 (IGFBP-3) localizes to and modulates proliferative epidermal keratinocytes in vivo

BACKGROUND

The colocalization of insulin-like growth factor binding protein-3 (IGFBP-3) and IGF-I receptor (IGF-IR) in the basal/germinative layer of the epidermis suggests a key role in modulating epidermal homeostasis.

OBJECTIVES

We aimed to clarify both the specific cellular localization and the effect of excess epidermal IGFBP-3 on keratinocyte proliferation.

METHODS

(i) Total RNA was isolated from fluorescence-activated cell sorted basal human keratinocyte subtypes [keratinocyte stem cells, transit amplifying keratinocytes (TA), postmitotic differentiating keratinocytes (PMD)], and real-time polymerase chain reaction analysis was used to determine the abundance of IGFBP-3 and IGF-IR mRNAs. (ii) An IGFBP-3 transgenic mouse model was then used to assess the effect of excess epidermal IGFBP-3 on keratinocyte proliferation. Excess epidermal IGFBP-3 mRNA and protein was determined by in situ hybridization and immunohistochemistry, respectively.

RESULTS

(i) The highest levels of IGFBP-3 mRNA were detected in TA keratinocytes, in contrast to IGF-IR mRNA levels which were highest in PMD keratinocytes. (ii) Elevated human IGFBP-3 mRNA and protein was confirmed in the epidermis of skin derived from transgenic mice. Excess IGFBP-3 reduced the relative percentage of proliferative keratinocytes (Ki67 positive) irrespective of skin location (belly, back and tail). Thus, in the epidermis, IGFBP-3 mRNA is highly expressed by proliferative keratinocytes (TA) and overexpression of IGFBP-3 inhibits keratinocyte proliferation.

CONCLUSIONS

We conclude that in vivo IGFBP-3 ensures epidermal homeostasis via downregulation of keratinocyte proliferation, and thus modulates the early stages of keratinocyte differentiation.

Development of an ideal starch saccharification process using amylolytic enzymes from thermophiles

The extensive efforts to screen thermophilic fungi and bacteria, isolated from various environmental samples, have resulted in the selection of Thermomucor indicae-seudaticae, Geobacillus thermoleovorans NP33 and G. thermoleovorans NP54 for the production of glucoamylase, amylopullulanase and alpha-amylase, respectively. Submerged and solid-state fermentation processes were optimized for maximizing the secretion of glucoamylase by T. indicae-seudaticae. The production of amylopullulanase and alpha-amylase by NP33 and NP54 in submerged fermentation was also optimized. Glucoamylase was optimally active at pH 7.0 and 60 degrees C and was shown to saccharify soluble as well as raw starches. Amylopullulanase and alpha-amylase exhibited optima at pH 7.0 and 100 degrees C and saccharified starch efficiently. Differential inhibition and action on mixed substrates clearly suggested that there are two separate active sites for alpha-amylase and pullulanase activities of amylopullulanase. Both alpha-amylase and amylopullulanase are high maltose-forming and Ca(2+)-independent. These amylolytic enzymes have been shown to be useful in starch saccharification alone and in combination.

The treatment of skin carcinoma, induced by UV B radiation, using 1-oxo-5beta, 6beta-epoxy-witha-2-enolide, isolated from the roots of Withania somnifera, in a rat model

Histopathological studies of the cutaneous tissues of Wistar rats exposed to UV B radiation (294 nm) for 20 days and rats exposed to UV B radiation for 20 days, followed by topical treatment with benzoyl peroxide, a tumor promoter (20 mg/animal/0.2 ml acetone) twice a week for 1 month, and kept under observation for 12 weeks, demonstrate the development of malignancy. Pretreatment of the animals with 1-oxo-5beta, 6beta-epoxy-witha-2-enolide (20 mg/kg bwt.), isolated from the roots of Withania somnifera, prior to exposing the animals to UV B radiation, prevents the incidence of skin carcinoma. The administration of 1-oxo-5beta, 6beta-epoxy-witha-2-enolide, to the animals after exposing them to UV B radiation/UV B radiation and benzoyl peroxide also prevents the occurrence of malignancy in the cutaneous tissue. Immunohistochemical staining of the cutaneous tissues of rats exposed to UV B radiation show the presence of p53 + foci (clusters of cells containing the mutated p53 protein), whereas an absence of p53 + foci is observed in animals pretreated with 1-oxo-5beta, 6beta-epoxy-witha-2-enolide. These results prove that 1-oxo-5beta, 6beta-epoxy-witha-2-enolide has the potential for acting as an effective agent to prevent the incidence of skin carcinoma induced by UV B radiation.

Role of in vivo proton MR spectroscopy in the evaluation of adult brain lesions: our preliminary experience

CONTEXT

A definite diagnosis and characterization of intracranial mass lesions, based on structural Magnetic Resonance Imaging (MRI) alone may be difficult. In such cases Proton Magnetic Resonance Spectroscopy (1H-MRS) along with other non-invasive techniques represents an advance in the specificity of brain lesion diagnosis.

AIMS

The primary aim of this study was to evaluate the extent of the utility of 1H-MRS in adult brain tumors and their differentiation from similar-appearing space-occupying lesions.

MATERIAL AND METHODS

MRS studies were performed on 1.5 Tesla whole body MR system using standard imaging head coil. Sixty patients (aged 30-65 years), including 35 males (31-65 years) and 25 females (30-65 years) were studied, along with 25 age-matched healthy volunteers (30-64 years). The Student 't' test was used to statistically analyze the spectroscopic data for significant difference in the metabolite ratios of the lesions from normal brain tissue.

RESULTS

The Cho/Cr ratio was significantly raised in low and high-grade glioma and meningioma patients (1.85 +/- 0.36, 3.50 +/- 1.00 and 6.65 +/- 2.83 respectively) (mean +/- standard deviation), as compared with the control group (1.16 +/- 0.18); and NAA/Cr and NAA/Cho ratios were found to be lower than normal values in our study (P<0.01). However, in the non-neoplastic lesions, the Cho/Cr ratios were not statistically significant. The tubercular lesions revealed an average Cho/Cr ratio of 1.24 +/- 0.18, while it was 1.14 +/- 0.07 for infarcts.

CONCLUSION

MR Spectroscopy was useful to arrive at a more definitive diagnosis in doubtful intracranial space-occupying lesions with similar morphological imaging patterns.

Conservative management of a complication of neonatal teeth: a case report

A case report of neonatal teeth in a 4 month old male infant with ulceration on ventral surface of the tongue and its conservative management, is presented.

Downregulation of plasma membrane expression/cytoplasmic accumulation of beta-catenin predicts shortened survival in non-small cell lung cancer. A clinicopathologic study of 100 cases

The E-cadherin-catenin complex proteins function in cell-cell adhesion and have been reported to be dysregulated in various human malignancies. Beta catenin is a cytoplasmic protein that associates with tyrosine kinase receptors and modulates cytoskeletal dynamics. It also plays a role in the Wnt signaling pathway. During neoplastic transformation, the phosphorylation of beta-catenin causes a loss of intercellular adhesions resulting in increased tumor cell motility and invasiveness. Tissue sections from 100 cases of non-small cell lung cancer (NSCLC) were immunostained with a monoclonal beta-catenin antibody. There were 47 squamous cell carcinomas (SCC) and 53 adenocarcinomas (AC) in the study group. Plasma membrane/cytoplasmic beta-catenin immunoreactivity was scored for intensity and distribution and correlated with tumor stage, grade and survival. Plasma membrane/cytoplasmic immunoreactivity for beta-catenin protein was observed in 71 (71%) of 100 NSCLC. 44 (94%) of 47 SCC and 27 (51%) of 53 AC expressed beta catenin. On univariate analysis, loss of beta catenin expression correlated with high tumor stage (p = 0.025), large tumor size (p = 0.02) and decreased patient survival (p = 0.04). The loss of beta catenin expression associated with high grade NSCLC reached near significance (p = 0.07). On multivariate analysis, the loss of beta catenin expression independently predicted shortened overall patient survival in NSCLC (p = 0.05). Beta catenin expression loss is associated with advanced tumor stage and is an independent predictor of shortened patient survival in NSCLC.

Regulation of catalytic function by molecular association: structure of phospholipase A2 from Daboia russelli pulchella (DPLA2) at 1.9 A resolution

The crystal structure of phospholipase A(2) from the venom of Daboia russelli pulchella has been refined to an R factor of 0.216 using 17,922 reflections to 1.9 A resolution. The structure contains two crystallographically independent molecules in the asymmetric unit. The overall conformations of the two molecules are essentially the same except for three regions, namely the calcium-binding loop including Trp31, the beta-wing and the C-terminal residues 119-131. Although these differences have apparently been caused by molecular packing, they seem to have functional relevance. Particularly noteworthy is the conformation of Trp31, which is favourable for substrate binding in one molecule as it is aligned with one of the side walls of the hydrophobic channel, whereas in the other molecule it is located at the mouth of the channel, thereby blocking the entry of substrates leading to loss of activity. This feature is unique to the present structure and does not occur in the dimers and trimers of other PLA(2)s.

Role of the linker region of the anion-stimulated ATPase ArsA. Effect of deletion and point mutations in the linker region

The anion-stimulated ATPase ArsA in Escherichia coli consists of two homologous halves, A1 and A2, which are connected by a 40-amino acid long stretch of residues designated as the linker region. The linker region of ArsA lies in close proximity of the nucleotide-binding domain(s) of ArsA and is involved in significant conformational changes on binding of the substrates. Hence, it has been suggested earlier that the linker may play an important role in the function of ArsA. The aim of the present study was to determine the role of the linker by deletion and by site-directed mutagenesis of specific residues. Effect of deletion of the linker was determined by using the in vivo complementation approach where two halves of ArsA were co-expressed either with or without the linker region. Two co-expressed halves of ArsA conferred arsenite resistance only if the linker region was present on one of the halves. Of the six different point mutations created in the linker region, three (G284S, R290S, and D303G) were seen to drastically affect the catalytic function of ArsA. In addition, these three mutant alleles conferred arsenite sensitivity in cells carrying the wild type arsB gene. Trypsin proteolysis studies carried out with the purified proteins showed that the A1 nucleotide-binding domain in D303G protein has a conformation different from the wild type ArsA, suggesting that the linker region interacts with the nucleotide-binding domain(s) of ArsA. Based on the studies presented here, we propose that, in addition to providing flexibility, the nature of the residues themselves in the linker region is important for the conformation of the nucleotide-binding domains and for the catalytic function of ArsA.

A prospective study of sensitivity and specificity of adenosine deaminase estimation in the diagnosis of tuberculosis pleural effusion

We prospectively evaluated the usefulness of adenosine deaminase [ADA] estimation in the diagnosis of tuberculosis [TB] pleural effusion. Seventy five subjects with pleural effusion were studied. Forty eight of them had TB pleural effusion [M:F: 37:11; mean age 33 +/- 14.4 years range 17-76] and the remaining 27 had pleural effusion due to causes other than TB [non-TB group] [M:F: 19:8; mean age 47.3 +/- 16.5 years; range 17-75]. Pleural fluid [PF] ADA levels were significantly higher in TB (n=48; mean 95.8 +/- 57.5 IU/L) compared with non-TB group (n=27; mean 30.7 +/- 27.2 IU/L) [p<0.001]. Serum ADA [S-ADA] levels were also significantly higher in TB (n=45; mean 39.6 +/- 18.3 IU/L) compared with non-TB group (n=26; mean 18.0 +/- 13.7 IU/L) [p<0.001]. PF-ADA levels were higher compared to S-SDA in TB (p <0.001) and non-TB groups [p<0.01]. Using a cut off of 35 IU/L, the sensitivity and specificity of PF-ADA in the diagnosis of TB was computed to be 83.3% and 66.6% respectively. At a cut-off level of 100 IU/L, PF-ADA was found to have a sensitivity 40% and specificity 100%. From this study it is concluded that, using 100 IU/L as the cut-off, it is possible to avoid pleural biopsy to ascertain the diagnosis of TB in as much as 40% of the patients.

A biologically active constituent of withania somnifera (ashwagandha) with antistress activity

In Ayurvedic medicine,Withania somnifera (Ashwagandha) is well known for its anti-stress activity. A passive rat experimental model, where the animals are subjected to multiple stress of cold, hypoxia, restraint (C-H-R) has been developed to evaluate adaptogenic properties of various fractions of W. somnifera root extracts. We have carried out extraction of roots of W. somnifera with water and further isolated one of the active constituents called compound X and also tested its anti-stress activity in C-H-R model. The effect of administration of W. somnifera water suspension (360 mg/Kg bw) and compound X (20mg/Kg bw) on the fall and recovery of colonic temperature was noted. There was an increase of ≈38% and ≈54% in the time taken to attain T(rec) 23°C by rats given a single dose of fresh aqueous suspension and biologically active constituent (Compound X) respectively, where as decrease in the recovery time to attain T(rec) 37°C is ≈13% and ≈33% respectively, as compared to control group. It is clear that rats treated with the fresh aqueous suspension and compound X ofWithania somnifera, could withstand the multiple stress of C-H-R better than control group.

Optical visualization of microsomal degranulation by a carcinogen

We report here for the first time the optical visualization of microsomal degranulation induced by a carcinogen (p-dimethylaminoazobenzene), employing analytical ultracentrifugation. Our observations demonstrate that electrophiles of a carcinogen can disrupt ribosome-membrane interaction in rough microsomes by their attacks on nucleophilic components of the reticular membrane-ribosome complex involved in protein synthesis for export from the cytosol. Lack of exported proteins can adversely affect signal transduction across plasma membrane, possibly leading to carcinogenesis.

Apoptosis and bcl-2 expression in prostate cancer: significance in clinical outcome after brachytherapy

PURPOSE

Radiation induced apoptosis of prostate cancer cells may have therapeutic and prognostic significance in patients treated with radiotherapy. We determined whether the ability of prostate tumor cells to undergo apoptosis has potential value for predicting the clinical response of patients with prostate cancer to brachytherapy.

MATERIALS AND METHODS

A total of 76 patients with clinical stages T1 to 2 disease who were not receiving adjuvant therapy underwent transperineal implantation with 125iodine or 103palladium seeds and biopsy 7 to 23 months (median 12) after therapy. Nonresponders were classified using the American Society for Therapeutic Radiology and Oncology criteria. The apoptotic index was analyzed using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay in archived biopsy specimens from 76 treated and 19 matched pretreatment control patients. Serial sections of prostatic tumors were also evaluated for the expression of bax and bcl-2 proteins (apoptosis regulators) by immunohistochemical testing.

RESULTS

A significant increase in the apoptotic index was detected in post-brachytherapy compared with pretreatment prostate specimens (3.1% versus 2%, p <0.05), as well as in patients with negative biopsy at followup compared with those with persistent malignancy (3.4% versus 1.8%, p = 0.02). In addition, there was a significant elevation in bcl-2 expression in prostatic tissue in patients with treatment failure compared with responders (30.5% versus 13.1%, p <0.05).

CONCLUSIONS

To our knowledge this is the first study to establish a correlation of apoptosis induction and bcl-2 over expression with treatment outcome in patients with prostate cancer after brachytherapy. Our findings have significant clinical implications for identifying the value of the apoptotic index and bcl-2 expression in prostatic tumors for predicting the therapeutic response to brachytherapy.

Apoptosis and bcl-2 expression in prostate cancer: significance in clinical outcome after brachytherapy

PURPOSE

Radiation induced apoptosis of prostate cancer cells may have therapeutic and prognostic significance in patients treated with radiotherapy. We determined whether the ability of prostate tumor cells to undergo apoptosis has potential value for predicting the clinical response of patients with prostate cancer to brachytherapy.

MATERIALS AND METHODS

A total of 76 patients with clinical stages T1 to 2 disease who were not receiving adjuvant therapy underwent transperineal implantation with 125iodine or 103palladium seeds and biopsy 7 to 23 months (median 12) after therapy. Nonresponders were classified using the American Society for Therapeutic Radiology and Oncology criteria. The apoptotic index was analyzed using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling assay in archived biopsy specimens from 76 treated and 19 matched pretreatment control patients. Serial sections of prostatic tumors were also evaluated for the expression of bax and bcl-2 proteins (apoptosis regulators) by immunohistochemical testing.

RESULTS

A significant increase in the apoptotic index was detected in post-brachytherapy compared with pretreatment prostate specimens (3.1% versus 2%, p <0.05), as well as in patients with negative biopsy at followup compared with those with persistent malignancy (3.4% versus 1.8%, p = 0.02). In addition, there was a significant elevation in bcl-2 expression in prostatic tissue in patients with treatment failure compared with responders (30.5% versus 13.1%, p <0.05).

CONCLUSIONS

To our knowledge this is the first study to establish a correlation of apoptosis induction and bcl-2 over expression with treatment outcome in patients with prostate cancer after brachytherapy. Our findings have significant clinical implications for identifying the value of the apoptotic index and bcl-2 expression in prostatic tumors for predicting the therapeutic response to brachytherapy.

Structure of a serine protease proteinase K from Tritirachium album limber at 0.98 A resolution

X-ray diffraction data at atomic resolution to 0.98 A with 136 380 observed unique reflections were collected using a high quality proteinase K crystals grown under microgravity conditions and cryocooled. The structure has been refined anisotropically with REFMAC and SHELX-97 with R-factors of 11.4 and 12.8%, and R(free)-factors of 12.4 and 13.5%, respectively. The refined model coordinates have an overall rms shifts of 0.23 A relative to the same structure determined at room temperature at 1.5 A resolution. Several regions of the main chain and the side chains, which were not observed earlier have been seen more clearly. For example, amino acid 207, which was reported earlier as Ser has been clearly identified as Asp. Furthermore, side-chain disorders of 8 of 279 residues in the polypeptide have been identified. Hydrogen atoms appear as significant peaks in the F(o) - F(c) difference electron density map accounting for an estimated 46% of all hydrogen atoms at 2sigma level. Furthermore, the carbon, nitrogen, and oxygen atoms can be differentiated clearly in the electron density maps. Hydrogen bonds are clearly identified in the serine protease catalytic triad (Ser-His-Asp). Furthermore, electron density is observed for an unusual, short hydrogen bond between aspartic acid and histidine in the catalytic triad. The short hydrogen bond, designated "catalytic hydrogen bond", occurs as part of an elaborate hydrogen bond network, involving Asp of the catalytic triad. Though unusual, these features seem to be conserved in other serine proteases. Finally there are clear electron density peaks for the hydrogen atoms associated with the Ogamma of Ser 224 and Ndelta1 of His 69.

Non-serotonergic potentiation by (-)-pindolol of DOI-induced forward locomotion in rats: possible involvement of beta-adrenoceptors?

[1] We have previously shown that the beta-adrenergic/5-HT1 receptor partial agonist (-)-pindolol (2.0-32.0 micromol kg(-1)) enhances the increase in forward locomotion in rats produced by the 5-HT2 receptor agonist DOI (0.7 micromol kg(-1)) via net activation of post-synaptic 5-HT2 receptors. [2] It was found that neither the 5-HT1A receptor agonist and partial agonist, (+/-) 8-OH-DPAT (0.2-2.4 micromol kg(-1)) and (S)-(-)-UH-301, respectively, nor the 5-HT1A receptor antagonist WAY-100635 (0.09-1.5 micromol kg(-1)), substituted for (-)-pindolol in this in vivo behavioral model. [3] This also applies to the 5-HT1B receptor agonist and antagonist anpirtoline (0.3-4.0 micromol kg(-1)) and isamoltane (1.0-64.0 micromol kg(-1)), respectively. Neither of these compounds mimicked (-)-pindolol in its interactions with DOI. [4] The (-)-pindolol/DOI-induced increase in forward locomotion could be antagonized by the beta1 adrenoceptor antagonist betaxolol (24 micromol kg(-1)). [5] It is suggested that the intrinsic efficacy of (-)-pindolol at beta-adrenoceptors is an important aspect of its in vivo pharmacodynamic profile.

Enrichment for murine keratinocyte stem cells based on cell surface phenotype

The identification and physical isolation of epithelial stem cells is critical to our understanding of their growth regulation during homeostasis, wound healing, and carcinogenesis. These stem cells remain poorly characterized because of the absence of specific molecular markers that permit us to distinguish them from their progeny, the transit amplifying (TA) cells, which have a more restricted proliferative potential. Cell kinetic analyses have permitted the identification of murine keratinocyte stem cells (KSCs) as slowly cycling cells that retain [(3)H]thymidine ([(3)H]Tdr) label, termed label-retaining cells (LRCs), whereas TA cells are visualized as rapidly cycling cells after a single pulse of [(3)H]Tdr, termed pulse-labeled cells (PLCs). Here, we report on the successful separation of KSCs from TA cells through the combined use of in vivo cell kinetic analysis and fluorescence-activated cell sorting. Specifically, we demonstrate that murine dorsal keratinocytes characterized by their high levels of alpha(6) integrin and low to undetectable expression of the transferrin receptor (CD71) termed alpha(6)(bri)CD71(dim) cells, are enriched for epithelial stem cells because they represent a minor ( approximately 8%) and quiescent subpopulation of small blast-like cells, with a high nuclear:cytoplasmic ratio, containing approximately 70% of label-retaining cells, the latter being a well documented characteristic of stem cells. Conversely, TA cells could be enriched in a phenotypically distinct subpopulation termed alpha(6)(bri)CD71(bri), representing the majority ( approximately 60%) of basal keratinocytes that are actively cycling, and importantly contain approximately 70% of [(3)H]Tdr pulse-labeled cells. Importantly, immunostaining of dorsal skin revealed the presence of CD71(dim) cells in the hair follicle bulge region, a well documented location for KSCs.

Functional characterization of cultured cells derived from an intraepidermal carcinoma of the skin (IEC-1)

We have successfully isolated a cell line (IEC-1) from an intraepidermal carcinoma of the skin of a patient and compared its behavior, in vitro, to normal human epidermal keratinocytes (HEK) and squamous cell carcinoma cell lines (SCCs). HEK differentiation comprises an initial growth arrest followed by an induction of squamous differentiation-specific genes such as transglutaminase type 1 (TG-1). Using thymidine uptake and TG-1 induction as markers of proliferation and differentiation, respectively, we were able to show that HEKs and the IEC-1 cells undergo growth arrest and induce TG-1 mRNA expression in response to various differentiation-inducing stimuli, while neoplastic SCC cell lines did not. However, differentiation in HEKs was an irreversible process whereas differentiation of the IEC-1 cells was reversible. Furthermore, growth of IEC-1 cells in organotypic raft cultures revealed differences in their ability to complete a squamous differentiation program compared with that of normal HEKs. The IEC-1 cells also exhibited a transitional phenotype with respect to replicative lifespan; HEKs had a lifespan of 4-6 passages, IEC-1 cells of 15-17 passages, and SCC cells were immortal. These alterations in IEC-1 cell behavior were not associated with functional inactivation or mutations of the p53 gene. These data indicate that the IEC-1 cells, derived from a preneoplastic skin tumor, exhibit differences in their ability to undergo terminal differentiation and have an extended replicative lifespan.

A clinico-epidemiological profile of non-healing wounds in an Indian hospital

One hundred patients with non-healing wounds of more than six weeks' duration were studied for clinico-epidemiological factors and their correlation with healing time. The majority of subjects were aged 30-59 years; those aged 50 and over had significantly delayed healing. Most of the subjects were farmers and physical labourers. Leprosy was the most common cause of non-healing wounds, followed by diabetes, trauma and venous ulcers; the lower limbs were the most common site of involvement. Diabetic wounds were more common in those aged 40 years and above. Diabetic wounds were slower to heal than others. The time to healing was calculated from the day subjects received treatment advice at the wound clinic. Seventy-five of the study group were included for calculation of healing time. The others were lost to follow-up or excluded for other reasons.