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P LoGerfo

Publications and source records attributed to P LoGerfo.

At least 19 recordsLinked to original sources
PubMed1996

A novel tumor-derived mediator that sensitizes cytokine-resistant tumors to tumor necrosis factor.

Therapeutic successes following treatment of murine tumors with tumor necrosis factor-alpha (TNF) have not been easily applied to clinical oncology because the concentrations of TNF required in humans induces systemic toxicity. This has led us to identify mediators which could sensitize tumors to the effects of TNF, permitting administration of lower doses and possible realization of the therapeutic potential of this cytokine. Our study reports the ability of a novel cytokine, endothelial-monocyte-activating polypeptide II (EMAP II), to sensitize initially resistant murine and human tumors to TNF-induced regression employing a murine model. Recombinant (r) EMAP II was purified from Escherichia coli transformed with a plasmid expressing mature EMAP II. The B16 melanoma, raised in C57BL/6 mice, or a human fibrosarcoma (HT-1080), grown in immunocompromised mice, was injected intratumorally with either vehicle or rEMAP II/heat-treated EMAP II (50-100 micrograms) followed by systemic TNF/heat-treated TNF (5 micrograms) and assessed for tumor volume, hemorrhage, and histologic appearance. Both the B16 melanoma and the HT-1080 human fibrosarcoma underwent thrombohemorrhagic and acute inflammatory changes concomitant with regression or significantly slowed growth after administration of intratumor EMAP II followed by systemic TNF. Omission or inactivation of either cytokine abrogated this effect. These results demonstrate that local treatment of certain tumors with EMAP II results in enhanced susceptibility to TNF-mediated induction of thrombohemorrhage and regression.

Animals↗
PubMed1993

Decreased levels of protein kinase C enzyme activity and protein kinase C mRNA in primary colon tumors.

PURPOSE: We have previously reported decreased protein kinase C (PKC) enzyme activity in primary human colorectal carcinomas. The purpose of this study was to extend these findings to a larger number of cases and to also examine the levels of expression of mRNAs that encode specific isoforms of PKC in these tumors. METHODS: Colorectal carcinomas and paired grossly normal adjacent mucosal samples were collected from 39 patients. Complete histopathologic analyses were performed on all samples. PKC enzyme activity in both the cytosolic and particulate fractions was quantitated by measuring the amount of 32P incorporated into histone Type III-S. Northern blot nucleic acid hybridization was performed using polyA+ RNA extracted from both the tumor and normal tissue samples and 32P-labeled probes for specific isoforms of PKC. The paired sample t-test was used to determine the statistical significance of tumor to normal ratios of both enzyme activity and mRNA levels. RESULTS: The mean value for cellular PKC enzyme activity in the colon tumors from 39 patients was about 60 percent of that found in the paired adjacent grossly normal mucosa samples (P < 0.001). The subcellular distribution of PKC activity was similar in normal and tumor samples (about 70 percent in the particulate fraction). The abundance of PKC alpha mRNAs varied considerably among 28 tumor/normal pairs, with a mean tumor to normal (T:N) ratio of 1.0 +/- 0.6 for the 9.9-kb mRNA band and 1.4 +/- 0.7 for the 3.5-kb band. The abundance of PKC beta mRNAs was decreased in 30 of 39 tumors, with a mean T:N ratio of 0.6 +/- 0.4 for both the 9.4- and 3.5-kb bands for all 39 samples (P < 0.001). None of the parameters measured correlated with Dukes stage or the grade of the tumor. CONCLUSIONS: These studies extend previous evidence that total PKC enzyme activity is frequently decreased in primary human colon tumors. Our finding that this is often associated with decreased levels of PKC beta mRNA suggest that this is not simply due to post-translational down-regulation of this enzyme system. Further studies are required to determine whether these changes in PKC alpha and PKC beta mRNAs are due to altered de novo transcription or mRNA stability. It will also be of interest to examine the expression of other isoforms of PKC in colon tumors.

Adult↗
PubMed1992

Changes in type I collagen following laser welding.

Selection of ideal laser parameters for tissue welding is inhibited by poor understanding of the mechanism. We investigated structural changes in collagen molecules extracted from rat tail tendon (> 90% type I collagen) after tissue welding using an 808 nm diode laser and indocyanine green dye applied to the weld site. Mobility patterns on SDS-PAGE were identical in the lasered and untreated tendon extracts with urea or acetic acid. Pepsin incubation after acetic acid extraction revealed a reduction of collagen alpha and beta bands in lasered compared with untreated specimens. Circular dichroism studies of rat tail tendon showed absence of helical structure in collagen from lasered tendon. No evidence for covalent bonding was present in laser-treated tissues. Collagen molecules are denatured by the laser wavelength and parameters used in this study. No significant amount of helical structure is regenerated on cooling. We conclude that non-covalent interactions between denatured collagen molecules may be responsible for the creation of tissue welding.

Animals↗
PubMed1991

Fecal excretion, uptake and metabolism by colon mucosa of diacylglycerol in rats.

In a previous paper we demonstrated that human fecal bacteria can convert phosphatidylcholine to diacylglycerol (DAG), an activator of protein kinase C. The present study demonstrates that several foods contain appreciable levels of DAG, especially certain vegetable oils. On the other hand, when rats were administered [14C]-labeled DAG by intragastric intubation less than 0.1% of the administered radioactivity was recovered as DAG in the feces. Thus only negligible amounts of dietary DAG actually reach the colon. When [14C]DAG was injected directly into ligated segments of rat colon we found appreciable uptake of the intact DAG by the mucosal cells. The major metabolite was arachidonic acid, suggesting that the DAG lipase pathway is more active than the DAG kinase pathway in these cells. Taken together, these results are consistent with our hypothesis that much of the DAG present in the colonic lumen is produced by the intestinal bacteria and that this DAG can actually enter the colonic mucosal cells, where it might influence their function.

Animals↗
PubMed1991

Decreased levels of 1,2-sn-diacylglycerol in human colon tumors.

We have found that in 15 of 15 primary human colon tumors there was a significant decrease (by about 40%) in the levels of diacylglycerol when compared to paired adjacent normal mucosa samples. Assays on the same samples indicated that this decrease was seen both in tumors that did and did not display mutations in codon 12 of c-K-ras. These results, taken together with previous studies on protein kinase C, suggest that the protein kinase C signal transduction pathway is suppressed in human colon cancer.

Aged↗
PubMed1990

Production of diacylglycerol, an activator of protein kinase C, by human intestinal microflora.

Although dietary lipids have been implicated in colon cancer causation, the underlying mechanisms are not known. This paper indicates that when bacteria obtained from normal human feces are incubated with 14C-labeled phosphatidylcholine there is appreciable production of diacylglycerol (DAG), monoacylglycerol, and free fatty acid. Curiously, the production of DAG and monoacylglycerol, but not fatty acid, is strictly dependent on addition of certain bile acids to the incubation system. Among the bile acids tested deoxycholic acid is the most active. Assays of fecal specimens from 10 normal individuals demonstrate a 27-fold interindividual variation in the production of DAG in the in vitro assay system, and also in the absolute levels of DAG present in the same fecal samples. On the other hand, both parameters of DAG are quite constant in repeated fecal samples obtained from the same individual over a period of about 4 months. DAG is a normal physiological activator of protein kinase C, an enzyme that plays a key role in growth control and tumor promotion. We speculate, therefore, that DAG produced by the intestinal microflora might stimulate growth of colonic epithelial cells. Thus an interaction between dietary lipids, bile acids, and specific bacteria in the intestinal lumen could contribute to the risk of colon cancer development in humans.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1990

Increased levels of phorbin, c-myc, and ornithine decarboxylase RNAs in human colon cancer.

Our previous work on protein kinase C (PKC) and colon cancer has shown altered levels of PKC activity in human colon tumors, as well as activation of PKC by colon tumor promoters such as bile acids. To understand further the role of PKC in colon carcinogenesis, we analyzed the expression of phorbin, a gene induced by PKC activation, in a series of different stages of human colon tumors. As shown by northern blot analyses of poly (A)+ RNA, higher levels of phorbin RNA were seen in 26 colon tumor samples than in their adjacent normal colonic mucosa. There also appeared to be a correlation between the abundance of phorbin RNA in the tumors and the extent of invasion (tumor-to-normal tissue phorbin RNA ratio = 4.2, 8.0, and 11.9 for Dukes' A, B, and C, respectively). Phorbin RNA was also abundant in a human colon cancer line (HT29). We also examined the expression of other mitogen-responsive genes (c-myc, ODC, and beta-actin) in a set of 19 colon tumor samples. All tumors displayed significant (mean 3.8-fold) increases in the level of c-myc RNA compared with their adjacent normal colonic mucosa. About 47% and 16% of these tumor samples also showed increased levels of ODC (mean 3.1-fold) and beta-actin (mean 1.6-fold) RNA, respectively. The increased levels of c-myc, ODC, and beta-actin RNA did not correlate with the extent of tumor invasion. Taken together, these results demonstrate that human colon tumors usually display increased levels of both phorbin and c-myc RNAs. The marked increases in phorbin RNA suggest that this could serve as a useful biomarker in studies on human colon cancer.

Actins↗
PubMed1989

Effect of polyethylene glycol-electrolyte lavage solution on intestinal microflora.

The bacterial flora of colonic aspirates taken after oral administration of a polyethylene glycol-electrolyte lavage solution to patients undergoing colonoscopy was analyzed by standard bacteriological methods and DNA hybridization techniques. The data were compared with those for normal feces collected from the same patients the day before treatment. The results indicate that the bacterial composition of feces differs from individual to individual but is not altered by the oral intake of a polyethylene glycol-electrolyte lavage solution. This pilot study demonstrates that routine colonoscopy aspirates taken after standard colonoscopy preparation accurately reflect the microflora of feces and therefore may be used in large-scale epidemiological studies.

Bacteria↗
PubMed1989

Oligonucleotide probe for detection and identification of Campylobacter pylori.

We have developed a novel and practical DNA-RNA hybridization assay for the detection and identification of Campylobacter pylori in the gastric mucosa. This technique utilizes a [32P]ddATP-labeled synthetic oligonucleotide probe complementary to a nucleotide sequence present in C. pylori 16S rRNA. This probe is very sensitive and reacted with all 23 strains of C. pylori tested. It is also highly specific, since there was no cross-reactivity with the heterologous organisms Campylobacter coli, C. fetus subsp. fetus, C. jejuni, and C. laridis or with Escherichia coli. Hybridization of the oligonucleotide probe with C. pylori RNA was completely inhibited by treatment of the membrane filters with RNase but not DNase. Although a gastric mucosa tissue homogenate slightly inhibited the hybridization, as few as 10(4) C. pylori cells could be detected even in the presence of 5 mg of gastric mucosa. Gastric biopsy specimens obtained from patients referred for upper gastrointestinal tract endoscopy were tested for C. pylori infection by direct oligonucleotide hybridization, and the results were compared with those of bacteriological cultures, the urease test, and histological observations. A comparison of the urease test and the oligonucleotide hybridization results showed an excellent correlation between the two methods. The clinical usefulness of this oligonucleotide-RNA hybridization method is discussed.

Campylobacter↗
PubMed1989

Inhibition of growth of human breast carcinomas in vivo by somatostatin analog SMS 201-995: treatment of nude mouse xenografts.

Minced tumor fragments were xenografted into subcutaneous tissue of the lateral thoracic regions of young adult, virgin female nude mice to study the effects of somatostatin analog SMS 201-995 on growth of estrogen-dependent (MCF-7) and estrogen-independent (BT-20) human breast carcinomas. When tumors became palpable (6 to 10 days), mice were assigned randomly to receive either SMS (4 to 50 micrograms) or acetate buffer (0.2 ml) subcutaneously twice a day. For MCF-7, mean tumor volume was significantly lower on day 20 and days 30 through 50 in SMS-treated mice than in controls (p less than 0.05), and tumor doubling time was increased from 13.2 to 19.0 days. Calculated growth increment was significantly lower with SMS than with buffer treatment (1.1 +/- 0.1 vs 1.9 +/- 0.2) (p less than 0.001). For BT-20, mean tumor volume of SMS-treated mice was slightly, but not significantly, lower than that of controls; however, calculated growth increment was significantly lower for SMS treatment (3.2 +/- 0.3 vs 3.9 +/- 0.4) (p +/- 0.001), and tumor doubling time was increased from 4.0 to 5.8 days. For MCF-7, flow cytometric DNA analysis of tumor biopsy samples demonstrated a reduced G2 + M phase with SMS treatment. We conclude that SMS slows the growth of both MCF-7 and BT-20 human breast cancer xenografts in nude mice and that SMS may be clinically useful in the management of patients with breast carcinoma.

Animals↗
PubMed1988

Changes in expression of oncogenes and endogenous retroviral-like sequences during colon carcinogenesis.

The possible roles in experimental colon carcinogenesis of two protooncogenes (c-myc and c-H-ras), two endogenous retrovirus-related DNA sequences [rat leukemia virus (RaLV) and the 30S sequence], and two cell cycle related genes (beta-actin and ornithine decarboxylase) were studied by analyzing the levels of their corresponding RNAs during the course of azoxymethane induced and high fat promoted colon carcinogenesis. F-344 male rats received three s.c. injections of azoxymethane (15 mg/kg) or normal saline and were then subdivided into high or low fat diet groups. During subsequent serial sacrifices normal colon mucosa, adenomas, and carcinomas were harvested for histology and RNA extraction. Seventy-one RNA samples were analyzed by the Northern blot hybridization procedure using the appropriate 32P-labeled DNA probes. A marked increase in the abundance of c-myc, RaLV, and 30S RNAs were seen in all of the colon tumors, including adenomas and invasive carcinomas. No or a very low level of expression of RaLV and c-myc RNA was found in the flat grossly normal mucosa adjacent to the tumors and in the mucosa of the control rats. Some of the colon tumors also displayed increased levels of c-H-ras, ornithine decarboxylase and beta-actin RNAs but these findings were less striking and more variable than those seen with c-myc, RaLV, and 30S RNAs. These results suggest that increased expression of the c-myc protooncogene and of the endogenous retrovirus-like sequences (RaLV) and 30S are hallmarks of colon carcinogenesis in this model system.

Animals↗
PubMed1987

Altered levels of protein kinase C and Ca2+-dependent protein kinases in human colon carcinomas.

Protein kinase C (PKC) is a Ca2+- and phospholipid-dependent protein kinase which is implicated in tumor promotion, since it has been demonstrated to be a high affinity receptor for tumor promoters such as 12-O-tetradecanoylphorbol-13-acetate. Colon carcinogenesis appears to proceed through distinct stages of initiation and promotion. The present studies show that PKC and calcium-dependent protein kinase specific activities are reduced in human colon carcinomas when compared to their normal adjacent colon mucosa. There were significantly higher Ca2+-dependent protein kinase and PKC specific activities observed in both the cytosolic and particulate fractions of the normal mucosa relative to the corresponding values obtained with the carcinoma fractions. The average specific activity ratios were 5.1 (normal cytosolic/carcinoma cytosolic) and 3.7 (normal particulate/carcinoma particulate) for PKC. PKC activity was reduced in the carcinoma tissues with respect to both protein and tissue weight. The percentage of Ca2+-dependent protein kinase and PKC activities that were present in the particulate fraction of each of the samples varied considerably among tissues, and in general there was no systematic difference between the carcinoma and normal mucosa samples. However, in the carcinoma samples that contained an extensive admixture of benign adenomatous tissue, the particulate fractions consistently contained greater than 60% of the total Ca2+-dependent protein kinase and PKC activities. The present studies indicate that colon carcinogenesis is associated with alterations in cellular levels of protein kinase activities.

Calcium↗
PubMed1987

Studies on protein kinase C and colon carcinogenesis.

To further understand the molecular mechanisms of bile acid-mediated colon tumor promotion, we have examined the possible role of protein kinase C (PKC) in this process. Protein kinase C has been implicated in tumor promotion because it is the receptor for the tumor promoter 12-0-tetradecanoyl-phorbol-13-acetate (TPA) and mediates the action of this compound as well as that of other tumor promoters and growth factors. Our studies show that, in a manner analogous to 12-0-tetradecanoyl-phorbol-13-acetate, deoxycholic acid (DOA) can induce a time-dependent cellular redistribution of PKC as well as a concentration-dependent overexpression of the ornithine decarboxylase gene. These results taken together with our previous findings demonstrating decreased levels of PKC in human colon carcinomas compared with adjacent normal mucosa provide evidence that PKC has a role in colon carcinogenesis.

Animals↗
PubMed1985

Presence of neuron-specific enolase and somatostatin in human parathyroid tissues.

The association of parathyroid abnormalities with apudomas prompted us to examine parathyroid tissues for the presence of neuron-specific enolase and somatostatin. Enolase was present in extracts of 29 out of 29 parathyroid specimens; tissue content was significantly higher in adenoma than in hyperplasia tissues (p less than 0.005). Somatostatin was present in 14 of 33 specimens. Immunoreactive somatostatin measured in tissue extracts' fluids coeluted on Sephacryl chromatography along with synthetic somatostatin-14 in studies of two parathyroid carcinoma specimens. Since neuron-specific enolase has been found only in neural and neuroendocrine cells, our results suggest that human parathyroid glands may contain neuroendocrine elements. The differential content of neuron-specific enolase in adenoma versus hyperplasia specimens may be diagnostically useful in selected cases. The significance of the presence of somatostatin in some but not all parathyroid tumors requires further investigation. Taken together with our prior findings of gastrin and pancreatic polypeptide in some human parathyroid glands, we postulate that human parathyroid tumors contain neural crest elements.

Adenoma↗
PubMed1983

Pancreatic polypeptide (PP) immunoreactivity in human parathyroid culture media.

Media from cultures of normal and abnormal human parathyroid fragments were assayed for parathyrin (PTH) and pancreatic polypeptide (PP) using sensitive radioimmunoassays. PP immunoreactivity was present in media (Day 6-7 in vitro) from cultures of 3/10 adenomas and 6/6 3 degrees hyperplastic glands (mean = 126. fmole/mg protein/day) (range = 6.-675.), and was not suppressed by 0 leads to 3 mM calcium challenge. PP was undetectable in media from cultures of one parathyroid carcinoma, one 1 degree hyperplasia, and one normal parathyroid. Medium C-terminal PTH levels were quite variable (26.-2,545,000. pg/mg protein/day). Presence of PP immunoreactivity in media from cultures of some hyperplastic parathyroids and some parathyroid adenomas suggests that PP may be released from these tissues in vitro. The significance of elevated PP levels in the MEA syndromes may be of special clinical relevance to this observation.

Adenoma↗
PubMed1983

Antigenic modulation of pan-T-cell and T-cell subset-specific markers.

The time course and extent of antigenic modulation induced by monoclonal antibodies OKT3, OKT4, OKT8, BE2, and BE3 was investigated. OKT3-induced antigenic modulation could be detected as early as after 3-hr incubation with the antibody and almost total removal of the OKT3-reactive antigen was seen by 42 hr. This modulation did not decrease the expression of T-cell antigens detected by OKT4 and OKT8. OKT3-modulated cells reexpressed the antigen after 42-hr incubation in OKT3-free media. BE3 (homologue of OKT1) also caused modulation of its surface antigen after 24-hr incubation. In contrast, OKT4 did not induce modulation even after 42-hr incubation with high concentrations of OKT4 antibody. Approximately 43% of the OKT8-reactive lymphocytes could be induced to modulate this antigen. A tumor-associated antigen present on neoplastic lymphocytes from patients with cutaneous T-cell lymphoma, recognized by monoclonal antibody BE2, also was not induced to modulate. These results suggest that antigenic modulation and the fate of the modulated antibody may be of importance to immunotherapeutic applications of these reagents.

Animals↗
PubMed1982

Radioiodine total body scan versus serum thyroglobulin levels in follow-up of patients with thyroid cancer.

Two groups of patients were studied to compare the efficacy of serum thyroglobulin (Tg) levels to 131I total body scans in the follow-up of patients with thyroid cancer. All of the group of 30 patients without recurrence had undetectable Tg levels on and off thyroid hormone replacement, and all had negative total body scan results although eight patients showed uptake in remnant thyroid tissue. In the second group of 37 patients with documented recurrent or metastatic disease, 34 (92%) had positive serum Tg levels, although the levels in five of these patients were undetectable while on thyroid replacement, and 31 (84%) had positive total body scan results. The false negative results of the two tests were not overlapping, and of those with positive Tg levels, 29 showed a significant increase once thyroid hormone therapy had been withdrawn. We conclude that although the percentages of positive Tg levels and body scan results in patients with recurrent disease are similar, both tests are required to minimize the number of patients with undiagnosed metastases. Second, thyroid-stimulating hormone suppression has a definite although unpredictable effect on serum Tg levels in patients with thyroid cancer, and thyroid hormone should be withdrawn prior to measurement of serum Tg to minimize the number of false negative results.

Follow-Up Studies↗