Comparison of Serum Uric Acid Levels in Patients with Stable Chronic Obstructive Pulmonary Disease and Patients with Acute Exacerbation.

Purine breakdown produces uric acid (UA) as a by-product. Serum UA levels have been reported to be higher in hypoxic people, including Chronic Obstructive Pulmonary Disease (COPD) patients. Serum UA has been suggested as a marker for impaired oxidative metabolism, and it is also thought to play a role in the prognosis and evaluation of respiratory disorders such as COPD. AIM: To compare serum uric acid levels in patients with stable Chronic Obstructive Pulmonary Disease and in patients with acute exacerbation (AE). MATERIAL: Study Design: An observational cross sectional comparative study was conducted which included 25 stable COPD patients and 25 patients with AE of COPD, all of them aged more than 40 years. Serum UA levels were measured and compared between the two groups. MATERIAL AND METHODS: Patients fulfilling inclusion criteria were included in the study after taking informed written consent. Blood sample was taken in plain vial and sent to Biochemistry lab for serum UA analysis. The analysis of serum UA was done using system reagent on Beckman Coulter AU Analyser. Complete blood count, blood urea, serum creatinine, arterial blood gas and oxygen saturation were also measured. OBSERVATION AND RESULTS: The mean serum UA in the Stable group was 6.19 mg/dL and in AE group was 7.45 mg/ dL. There was a statistically significant difference between the 2 groups in terms of serum UA levels with a p value of 0.021 and the mean serum UA level being highest in the AE group. In this study, statistically significant difference was also found between Stable and AE group in terms of mMRC grading of dyspnea (p< 0.001), Pack years (p< 0.001), pH (p=0.009), pO2 (p< 0.001) and pCO2 (p< 0.001). There was no statistically significant difference between Stable and AE group in terms of age, gender, total leucocyte count, blood urea, serum creatinine and HCO3 Conclusion: Serum UA may be a useful parameter in assessing disease severity and hypoxemia in known COPD patients and may be helpful in early intensive management. Increased serum UA levels denote poor state and bad prognosis. Since serum UA is a simple, inexpensive and readily available routine laboratory test, it can be used in risk stratification in patients with COPD and can help in early management of patients with COPD.

General route to synthesize of metal (Ni, Co, Mn, Fe) oxide nanostructure and their optical and magnetic behaviour.

Here we report a generalised way to prepare transitional metal (Ni, Co, Mn, Fe) oxide nanostructures via solvothermal route followed by controlled heat treatment. The method has been successfully involved to produce structurally uniform and well crystalline phase of the different metal (Ni, Co, Mn) oxide faceted nanoparticles and porous nanorods (Fe2O3) with highly anisotropic surfaces. The product materials were characterized by the X-ray powder diffraction and electron microscope (SEM, TEM) to investigate the structural and morphological details. Optical absorption study was carried out by UV-VIS spectrophotometer and the results are analysed on the basis of their electronic transitions of 3d shell and band energies. The details magnetic investigation was carried out by the measurement of magnetization with varying magnetic field and temperature. The observed magnetic behaviour is explained on the basis of uncompensated spins lying on the surface which is extremely anisotropic in the present systems of the synthesized materials.

Case report on carotid body tumor.

A 40 years old lady presented to us with the complaints of repeated attack of syncope with left sided neck swelling. Ultrasonography, Color Doppler study and arteriography were done which revealed a solid vascular mass in the carotid bifurcation. Mass was resected and histopathology was done. Histopathologic findings were typical of a carotid body tumour. As carotid body tumour is a rare disease. So, we are going to present this in this article.

Electronic absorption spectrum of triacetylene cation for astronomical considerations.

The A(2)Πg ← X(2)Πu electronic transition (4800-6000 Å) of triacetylene cation was measured in an ion trap, where the vibrational and rotational degrees of freedom were equilibrated to 25 K. The rotational profile of the origin band is predicted by a collisional-radiative rate model under conditions expected in diffuse interstellar clouds. Variation in the density of the surrounding gas, rotational temperature, and velocity dispersion are taken into account.

Detecting hidden spatial and spatio-temporal structures in glasses and complex physical systems by multiresolution network clustering.

We elaborate on a general method that we recently introduced for characterizing the "natural" structures in complex physical systems via multi-scale network analysis. The method is based on "community detection" wherein interacting particles are partitioned into an "ideal gas" of optimally decoupled groups of particles. Specifically, we construct a set of network representations ("replicas") of the physical system based on interatomic potentials and apply a multiscale clustering ("multiresolution community detection") analysis using information-based correlations among the replicas. Replicas may i) be different representations of an identical static system, ii) embody dynamics by considering replicas to be time separated snapshots of the system (with a tunable time separation), or iii) encode general correlations when different replicas correspond to different representations of the entire history of the system as it evolves in space-time. Inputs for our method are the inter-particle potentials or experimentally measured two (or higher order) particle correlations. We apply our method to computer simulations of a binary Kob-Andersen Lennard-Jones system in a mixture ratio of A(80)B(20) , a ternary model system with components "A", "B", and "C" in ratios of A(88)B(7)C(5) (as in Al(88)Y(7)Fe(5) , and to atomic coordinates in a Zr(80)Pt(20) system as gleaned by reverse Monte Carlo analysis of experimentally determined structure factors. We identify the dominant structures (disjoint or overlapping) and general length scales by analyzing extrema of the information theory measures. We speculate on possible links between i) physical transitions or crossovers and ii) changes in structures found by this method as well as phase transitions associated with the computational complexity of the community detection problem. We also briefly consider continuum approaches and discuss rigidity and the shear penetration depth in amorphous systems; this latter length scale increases as the system becomes progressively rigid.

D2Pi(u), C2Pi(u) <-- X2Pi(g) electronic transitions of NCCN+.

The electronic absorption spectrum of NCCN(+) in the gas phase was measured at approximately 15 K in a 22-pole ion trap. The spectra show two band systems assigned to the C(2)Pi(u)-X(2)Pi(g) and D(2)Pi(u)-X(2)Pi(g) transitions with origin band maxima at 17,363 (3) and 33,409 (5) cm(-1), respectively. Both absorptions show distinct vibrational structure with progressions in nu(2) as well as combinations of double quanta excitations in nu(4) and nu(5). Rotational structure of the 0(0)(0) bands could not be resolved, which indicates that the C(2)Pi(u) and D(2)Pi(u) states have a lifetime on the order of a hundred femtoseconds because of fast intramolecular processes.

Adult body dimension and determinants of chronic energy deficiency among the Shabar tribe living in urban, rural and forest habitats in Orissa, India.

AIMS: This study was conducted to examine variation of adult body dimension and prevalence of chronic energy deficiency (CED) with its determinants (socio-economic, nutrient and morbidity) among the Shabar tribe living in urban, rural and forest areas of Orissa, India. SUBJECTS AND METHODS: Anthropometric measurements along with socio-economic, nutrient consumption and morbidity patterns of 444 males and 489 females aged 20-60 years were collected from the Khurda and Cuttack districts. RESULTS: Major differences were found in fat mass rather than muscle mass between habitats, and the urban group showed higher values compared to rural and forest counterparts. The highest prevalence of undernutrition was observed among forest-dwelling males and rural females. Gender difference was higher in the rural area. Higher prevalence of CED was observed among illiterates, within larger families, economically poorer groups, those with inadequate nutrient consumption, and those who had experienced morbid conditions. However, sex and habitation-wise, the risk factors associated with CED were different. Notably, economic disparity and morbidity conditions were a significant risk factor of CED among rural females. CONCLUSION: Body fat content was found to be the major difference in body dimension across different habitats and rural women may be a vulnerable group.

Pentachlorophenol degradation by Pseudomonas stutzeri CL7 in the secondary sludge of pulp and paper mill.

A pentachlorophenol (PCP) mineralizing bacterium was isolated from the secondary sludge of pulp and paper mill and identified as Pseudomonas stutzeri strain CL7. This isolate used PCP as its sole source of carbon and energy and was capable of degrading this compound as indicated by stoichiometric release of chloride and biomass formation. P. stutzeri (CL7) was able to mineralize a high concentration of PCP (600 mg/L) than any previously reported Pseudomonad with PCP as sole carbon source. As the concentration of PCP increased from 50 to 600 mg/L, the reduction in the cell growth was observed and the PCP degradation was more than 90% in all studied concentrations. This isolate was able to remove 66.8% of PCP from the secondary sludge of pulp and paper mill when supplemented with 100 mg/L of PCP and grown for two weeks. This study showed that the removal efficiency of PCP by CL7 was found to be very effective and can be used in PCP remediation of pulp paper mill waste in the environment.

A novel simplistic fabrication technique for cranial epidural electrodes for chronic recording and stimulation in rats.

BACKGROUND: The demand for neuromodulatory and recording tools has resulted in a surge of publications describing techniques for fabricating devices and accessories in-house suitable for neurological recordings. However, many of these fabrication protocols use equipment which are not common to biological laboratories, thus limiting researchers to the use of commercial alternatives. New method:We have developed a simple yet robust implantable stimulating surface electrode which can be fabricated in all wet-bench laboratories. RESULTS: Female Sprague-Dawley rats received epidural implantation of the electrodes over the fore and hind limb areas of their motor cortex. Stimulation of the motor cortex successfully evoked fore- and hind limb motor outputs. The device was also able to record surface potentials of the motor cortex following epidural stimulation of the spinal cord. Comparisons with existing methods:For stimulation of the motor cortex, often stiff stainless or copper wires are roughly tucked underneath the skull, with little accuracy of localization. While, commercially available devices utilize burr holes and screw electrodes. Our new electrode design provides us stereotaxic accuracy that was not previously available. CONCLUSION: We developed a chronic implantable electrode capable of being fabricated in all wet-labs, are robust, versatile and electrically sensitive enough for long-term chronic use. The simple and versatile electrode design provides scientific, economical and ethical benefits.

Presynaptic control of transmission through group II muscle afferents in the midlumbar and sacral segments of the spinal cord is independent of corticospinal control.

Transmission of information from the terminals group II muscle afferents is subject to potent presynaptic modulation by both segmental group II and cutaneous afferents and by descending monoaminergic systems. Currently it is unknown whether descending corticospinal fibres affect this transmission. Here we have examined whether corticospinal tract activation modulates the size of monosynaptic focal synaptic potentials (FSPs) evoked by group II muscle afferents, and the excitability of intraspinal terminals of group II afferents, both of which are indices used to show presynaptic control. Conditioning stimulation of corticospinal pathways had no effects on the sizes of group II evoked FSPs in the midlumbar or sacral segments at either dorsal horn or intermediate zone locations. These stimuli also had no effect on the excitability of single group II afferent terminals in the dorsal horn of the midlumbar segments. As positive controls, we verified that the corticospinal conditioning stimuli used did effectively depress FSPs evoked from cutaneous afferents recorded at the same spinal locations as the group II field potentials in all experiments. Corticospinal tract conditioning stimuli did not consistently enhance or reduce the depression of group II FSPs that was evoked by stimulation of ipsilateral segmental group II or cutaneous afferents; in the large majority of cases there was no effect. The results reveal that the control of transmission of information from group II afferents in these regions of the spinal cord is independent of direct corticospinal control.

Body form and nutritional status among adult males of different social groups in Orissa and Bihar States in India.

This paper aims to carry out a biological investigation of the body form and nutritional status of the major social groups of Orissa and Bihar States in India. For this, Cormic Index (CI) and Body Mass Index (BMI) have been computed using data on height, sitting height and weight, taken from adult males of age 18-62 years of various ethnic groups in these two states. The subjects have been classified on the basis of chronic energy deficiency (CED). It is found that a substantial proportion of the people with CED are in the grade II and grade III categories. ANOVA, t-tests, correlation and regression were carried out separately. The results reveal that in Orissa, Scheduled Tribes are shorter, lighter and have lowest mean values of BMI and Cormic Index compared to other groups, but in Bihar, though the Scheduled Tribes are shorter, Scheduled Castes are lower in weight and have the lowest mean values of BMI. There are significant differences in BMI as well as in CI between Scheduled Tribes of Orissa and Bihar. Scheduled Castes and Tribes of Bihar have the highest percentage of CED with 64.71% and 57.45%, respectively. Muslims of Bihar are also affected (52.95%), but overall prevalence of CED is lower in Orissa (49.11%) than in Bihar (54.62%). BMI and CI are highly correlated for each of the social groups in Bihar and Orissa.

Whole time domestic child labor in metropolitan city of Kolkata.

We conducted this study to explore the socioeconomic conditions, and health and nutritional status of whole time child domestic labor. 330 children engaged in domestic child labor ranging between 8 to 14 years of age from the metropolitan city of Kolkata were studied. Majority of the domestic child laborers were girls and migrants coming from illiterate families. These children were physically, mentally or sexually abused. Further, they suffered from anemia, gastrointestinal tract infections, vitamin deficiencies, respiratory tract infections and skin diseases along with a high prevalence of malnutrition. The study highlights the poor state of domestic child labor in Kolkata, India.

Induction of carcinoembryonic antigen secretion and modulation of protein secretion/expression and fibronectin/laminin expression in human colon carcinoma cells by transforming growth factor-beta.

We have recently reported that TGF-beta induces a response similar to that of planar polar differentiation promoters in human colon carcinoma MOSER cells. N,N-Dimethylformamide and TGF-beta had similar effects on MOSER cells with respect to reversible inhibition of growth (both in monolayer culture and semisolid medium), induction of fibronectin expression and the induction of morphological alterations (Cancer Res., 47:2950-2954, 1987). Since the expression of carcinoembryonic antigen (CEA) has been reported to be modulated by planar polar compounds that promote differentiation in colon carcinomas, we addressed the issue of whether the differentiation-like effects of TGF-beta on these cells would also encompass modulation of CEA expression in the MOSER cells. The biological modulating effects of TGF-beta on extracellular matrix glycoprotein expression and the expression and secretion of cellular proteins were also studied in view of the reported modulating effects of this growth factor on untransformed, noncolonic cells. In this communication we report that TGF-beta induced the synthesis of fibronectin and laminin but not collagen IV. TGF-beta also induced CEA secretion in a dose-dependent manner. Elevated CEA secretion was detected following 48 h of TGF-beta treatment and a 16-fold increase in CEA secretion was observed following 7 days of treatment. The cells were committed to secrete CEA following one dose of TGF-beta treatment. The enhanced expression of four cellular proteins (Mr 42,000, Mr 48,000, Mr 52,000, and Mr 55,000) and the enhanced secretion of three proteins (Mr 66,000, Mr 200,000, and Mr 400,000) were also induced. Some of these protein alterations were detected as early as 6-24 h following TGF-beta treatment. It is concluded that TGF-beta modulated the production and secretion of CEA, the synthesis of fibronectin and laminin, and the expression and secretion of several cellular proteins in the colon carcinoma MOSER cells. To our knowledge, this is the first report on the modulation of CEA and laminin by TGF-beta in tissue-cultured cells, and is the first report on the modulation of cellular proteins by this growth factor in human colon carcinoma cells.

Examination of urokinase protein/transcript levels and their relationship with laminin degradation in cultured colon carcinoma.

Conditioned medium derived from the colon cancer cell lines was ineffective in solubilizing immobilized radiolabeled laminin. However, substantial degradation was observed in the presence of plasminogen and could be largely blocked by preincubation with polyclonal anti-urokinase antibody. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the solubilized products generated either by the conditioned medium or by authentic urokinase supplemented with plasminogen yielded identical results. Analysis of the spent medium for urokinase by an enzyme-linked immunosorbent assay method revealed a similar profile to that achieved with the laminin degradation assays for the six cell lines tested. However, Northern analysis of urokinase-specific mRNA indicated that protein levels could not be entirely predicted by steady-state levels of the transcript. In a previous study, undifferentiated colon cancer cell lines expressed larger amounts of the plasminogen activator into the conditioned medium compared with their well-differentiated counterparts. However, these earlier studies were performed using cells grown in defined medium which lacked epidermal growth factor (EGF). EGF has been reported to affect plasminogen activator levels. Consequently, to investigate the role of EGF in the modulation of urokinase protein/activity, cell types representative of well- and poorly differentiated colon cancer were examined for their sensitivity of expression to this growth factor. In the absence of EGF, primitive cell types secreted, on average, 5 times more urokinase than their well-differentiated counterparts. In response to EGF, however, well-differentiated cell lines exhibited 4- to 6-fold increases in these parameters while the primitive cell lines were refractory to the peptide. Consequently, the differences in urokinase protein expressed by the well- and poorly differentiated groups of cells were abolished by the presence of EGF. The expression of a well-differentiated phenotype by colon cancer cell types in vivo probably depends to some extent on laminin within a basement membrane. The data presented herein are consistent with the idea that depletion of this glycoprotein from a basement membrane by urokinase-dependent mechanisms may contribute to the undifferentiated phenotype seen with many of these malignancies.

Alterations of the biological characteristics of a colon carcinoma cell line by colon-derived substrata material.

This study documents the ability of substrata material derived from well but not poorly differentiated colon carcinoma cells to alter the biological characteristics of a separate colon carcinoma cell line (MOSERSF). To assess changes induced by the presence of these substrata, MOSERSF cells were screened for (a) morphological features, (b) secretion of carcinoembryonic antigen (CEA), (c) alteration of urokinase levels, and (d) sensitivity to the growth-inhibitory peptide transforming growth factor beta. Morphologically, MOSERSF cells grown on plastic displayed a rounded shape and could be detached by agitation. Subculturing of these cells onto substrata laid down by well differentiated (mature) colon carcinoma cells resulted in cell attachment and spreading. These changes did not manifest themselves when cells were plated on material derived from poorly differentiated (primitive) colon cells. Conditioned medium from MOSERSF cells grown on plastic or on colon-derived material from the well and poorly differentiated colon cells were compared for CEA levels. Substrata derived from undifferentiated cells were without effect on assayable CEA (substrata absent, 1.4 ng/ml/10(6) cells/72 h; substrata present, 1.4-1.7 ng/ml/10(6) cells/72 h). However, growth of MOSERSF cells on material deposited by well differentiated colon cells resulted in a 3-fold increase in the level of CEA. Spent medium was also analyzed for urokinase. A high level of the protease (20.3 ng/ml/10(6) cells/72 h) was expressed by MOSERSF cells. The concentration of the enzyme was reduced by over 50% when MOSERSF cells were propagated on substrata laid down by well differentiated cells. An enhanced sensitivity to the growth-retarding effects of transforming growth factor beta was seen with certain substrata. On plastic, transforming growth factor beta inhibited proliferation of MOSERSF cells with a median effective concentration of 0.65 ng/ml. However, on substrata from mature but not primitive cells, MOSERSF cells exhibited an increased sensitivity to the peptide (median effective concentration, 0.16 ng/ml). Colon-derived material obtained from both well differentiated and poorly differentiated colon carcinoma cells was compared after [35S]-methionine metabolic labeling. More [35S]methionine was incorporated into the material from the "mature" colon cells. The substrata could also be distinguished by quantitative differences in a number of high molecular weight proteins. Immunofluorescence of colon-deposited material revealed the presence of laminin and fibronectin.

Diverse cellular responses elicited from human colon carcinoma cells by transforming growth factor-beta.

We have recently characterized the growth-inhibitory and cellular responses [carcinoembryonic antigen (CEA) secretion, protein secretion, protein expression, fibronectin and laminin synthesis] of the human colon carcinoma MOSER cell line to transforming growth factor-beta (TGF-beta) (Cancer Res., 47: 2950, 1987; 48: 4059, 1988). We have also recently isolated a subline (MOSER R2) from the parental MOSER cells which, unlike the parental line, is relatively resistant to the growth-inhibitory effect of TGF-beta (Biochem. Biophys. Res. Commun., 150: 711, 1988). We now report on the characterization of the cellular responses of this resistant MOSER R2 subline to TGF-beta and compare its responses to that of the highly growth-inhibition-sensitive MOSER cell line. In view of the reported relationship between CEA expression and differentiation in colon cancer and the ability of colon-derived substrata material to modulate the phenotypic properties of colon cancer cells, additional characterization and direct comparison of the effects of TGF-beta on the two cell lines were also performed with respect to (a) cellular expression of CEA and CEA cross-reactive glycoproteins; and (b) colon-derived substrata material. Unlike the growth-inhibition-sensitive MOSER cells, TGF-beta had no effects on fibronectin/laminin synthesis nor on the cellular morphology of the resistant MOSER R2 cells. TGF-beta was also unable to modulate protein secretion and deposition of substrata material by these cells. However, several other responses of the resistant cells to TGF-beta were found to be similar to that of the sensitive MOSER cells. These responses include: (a) a prolonged and stable secretion of CEA; (b) a prolonged and stable induction of elevated cellular expression of CEA and CEA cross-reactive glycoproteins; and (c) enhancement of the expression of three cellular proteins with molecular weights corresponding to 52,000, 48,000, and 42,000. We further report that the differences observed in the responses to TGF-beta in the two cell lines were not due to differences in TGF-beta binding or other receptor parameters such as the expression of distinct TGF-beta receptor subspecies.

Restoration of normal growth control and membrane antigen composition in malignant cells by N,N-dimethylformamide.

The effects of the differentiation agent, N,N-dimethylformamide (DMF), on malignant AKR-MCA cells were studied. The properties of DMF-treated AKR-MCA cells were compared to those of the normal parental AKR-2B mouse embryo fibroblasts. AKR-MCA cells grown in 1% DMF were found to be more similar to their normal counterparts than to untreated AKR-MCA cells by several criteria. These criteria included the loss of the transformed morphology, a 2-fold reduction of doubling time, a 10-fold reduction of saturation density, and the complete loss of the ability to grow with anchorage independence. The expression of high-molecular-weight membrane antigens (Mr 110,000 to 450,000), which was found to be greatly reduced in AKR-MCA cells in comparison to normal AKR-2B cells, was restored by treatment of AKR-MCA cells with DMF. The expression of a low-molecular-weight AKR-MCA cell-associated membrane antigen, on the other hand was found to be suppressed. Studies on the mitogenic response of these cells indicated that AKR-MCA and AKR-2B cells may be regulated by different types of growth control. Growth-arrested AKR-MCA cells did not respond to epidermal growth factor, but responded to nutrient replenishment. AKR-2B cells, on the other hand, responded to epidermal growth factor, but did not respond to nutrient replenishment. Treatment of AKR-MCA cells with DMF restored their ability to respond to epidermal growth factor, while their ability to respond to nutrient replenishment was lost. The results of this study indicated that DMF treatment induced the normalization of malignant AKR-MCA cells with regard to membrane antigen composition and growth control properties.

Selective phosphorylation of cytosol proteins associated with transformation and restoration of normal phenotype in AKR mouse embryo fibroblasts.

Phosphoproteins from cytosol preparations of methylcholanthrene-transformed AKR mouse (AKR-MCA) cells were compared to those of their untransformed counterparts, AKR-2B cells, by two-dimensional electrophoresis following an in vitro 32P phosphorylation procedure using endogenous kinases and substrates. Five proteins were phosphorylated in the AKR-MCA cells which were not observed in the AKR-2B cells, while six proteins were phosphorylated in the untransformed cells which were not observed in the malignant cells. Treatment of AKR-MCA cells with 1% N,N-dimethylformamide induced the reversion of the malignant cells to a phenotype similar to that of untransformed AKR-2B cells (S. Chakrabarty et al., Cancer Res., 44: 2181, 1984). Treatment of AKR-MCA cells with dimethyl formamide resulted in the restoration of five of the AKR-2B-associated phosphorylations and abolished 2 of the AKR-MCA-associated phosphorylations. AKR-2B cells have been shown to respond to transforming growth factors with reversible phenotypic transformation (R. F. Tucker et al., Cancer Res., 43: 1581, 1983). Transforming growth factor treatment of AKR-2B cells induced all five of the AKR-MCA-associated phosphoproteins and the loss of all six of the AKR-2B phosphoproteins. Epidermal growth factor treatment of AKR-2B cells resulted in the phosphorylation of several proteins which were not observed in either AKR-MCA or untreated AKR-2B cells. Some, but not all, of the AKR-2B-associated phosphorylations were also observed in epidermal growth factor-treated cells. The results of these studies demonstrated qualitative and/or quantitative changes in cytosolic protein kinase-phosphatase activities between transformed and normal AKR-2B cells. Treatment of AKR-MCA cells with dimethylformamide resulted in the restoration of some of the normal AKR-2B cell-associated protein kinase-phosphatase activities.

Selective protein phosphorylation in heterogeneous subpopulations of human colon carcinoma cells.

Endogenous membrane and cytosolic and nuclear protein phosphorylations were compared among three well-characterized subpopulations of human colonic carcinoma cells that were originally isolated from a single human primary colon tumor. These intratumoral subpopulations of cells were found to differ significantly in their biological properties. Analysis of phosphoproteins by two-dimensional electrophoresis following 32P phosphorylation of subcellular fractions in a cell-free system or labeling intact cells in vivo revealed significant differences in the selective phosphorylation of membrane, cytosol, and nuclear proteins. The two-dimensional membrane, cytosol, and nuclear phosphoprotein profiles distinguished the three subpopulations of colonic carcinoma cells from each other. Silver-staining proteins from the three subpopulations were also compared. The two-dimensional, silver-stained electrophoretic profiles of nuclear proteins were essentially the same for all three subpopulations. The silver-stained electrophoretic profile of membrane and cytosolic proteins revealed only minor differences in the expression of polypeptides. Nevertheless, these changes could also distinguish the three subpopulations. The results of this study suggest that minor differences in the expression of cytosolic and membrane proteins exist in intratumoral subpopulations of colonic cells. However, a significantly greater degree of heterogeneity was found to be associated with post-translational modification of proteins by phosphorylation and/or dephosphorylation. These modifications could play an important role in determining the expression of different biological properties among subpopulations of malignant cells.

Circumvention of deficient activation in mitomycin C-resistant human colonic carcinoma cells by the mitomycin C analogue BMY25282.

BMY25282, a newly designed analogue of mitomycin C (MMC) with the substitution of an amidine group at position 7 of MMC, can circumvent MMC resistance in a series of human colonic carcinoma cells that were selected for resistance to MMC (J.K.V. Willson et al., Cancer Res., 45:5281-5286, 1985). In this study MMC resistance was found to be associated with an inability of the resistant cells to activate MMC. However, both the MMC-sensitive and -resistant cells were observed to metabolize BMY25282 extensively in vitro to a reactive species capable of alkylating 4-(p-nitrobenzyl)pyridine (a trapping agent for activated drug). The results of these studies suggested that the deficient cellular reductive activating mechanism was associated with MMC resistance and that analogue BMY25282 was able to overcome this deficiency in MMC-resistant cells by virtue of its enhanced activation.