Real-time calculation of a limiting form of the Renyi entropy applied to detection of subtle changes in scattering architecture

Previously a new method for ultrasound signal characterization using entropy H(f) was reported, and it was demonstrated that in certain settings, further improvements in signal characterization could be obtained by generalizing to Renyi entropy-based signal characterization I(f)(r) with values of r near 2 (specifically r=1.99) [M. S. Hughes et al., J. Acoust. Soc. Am. 125, 3141-3145 (2009)]. It was speculated that further improvements in sensitivity might be realized at the limit r-->2. At that time, such investigation was not feasible due to excessive computational time required to calculate I(f)(r) near this limit. In this paper, an asymptotic expression for the limiting behavior of I(f)(r) as r-->2 is derived and used to present results analogous to those obtained with I(f)(1.99). Moreover, the limiting form I(f,infinity) is computable directly from the experimentally measured waveform f(t) by an algorithm that is suitable for real-time calculation and implementation.

Application of Renyi entropy for ultrasonic molecular imaging

Previous work has demonstrated that a signal receiver based on a limiting form of the Shannon entropy is, in certain settings, more sensitive to subtle changes in scattering architecture than conventional energy-based signal receivers [M. S. Hughes et al., J. Acoust. Soc. Am. 121, 3542-3557 (2007)]. In this paper new results are presented demonstrating further improvements in sensitivity using a signal receiver based on the Renyi entropy.

Properties of an entropy-based signal receiver with an application to ultrasonic molecular imaging

Qualitative and quantitative properties of the finite part, H(f), of the Shannon entropy of a continuous waveform f(t) in the continuum limit are derived in order to illuminate its use for waveform characterization. Simple upper and lower bounds on H(f), based on features of f(t), are defined. Quantitative criteria for a priori estimation of the average-case variation of H(f) and log E(f), where E(f) is the signal energy of f(t) are also derived. These provide relative sensitivity estimates that could be used to prospectively choose optimal imaging strategies in real-time ultrasonic imaging machines, where system bandwidth is often pushed to its limits. To demonstrate the utility of these sensitivity relations for this application, a study designed to assess the feasibility of identification of angiogenic neovasculature targeted with perfluorocarbon nanoparticles that specifically bind to alpha(v)beta3-integrin expression in tumors was performed. The outcome of this study agrees with the prospective sensitivity estimates that were used for the two receivers. Moreover, these data demonstrate the ability of entropy-based signal receivers when used in conjunction with targeted nanoparticles to elucidate the presence of alpha(v)beta3 integrins in primordial neovasculature, particularly in acoustically unfavorable environments.

Induction of hypervascularity without leakage or inflammation in transgenic mice overexpressing hypoxia-inducible factor-1alpha

Hypoxia-inducible factor-1alpha (HIF-1alpha) transactivates genes required for energy metabolism and tissue perfusion and is necessary for embryonic development and tumor explant growth. HIF-1alpha is overexpressed during carcinogenesis, myocardial infarction, and wound healing; however, the biological consequences of HIF-1alpha overexpression are unknown. Here, transgenic mice expressing constitutively active HIF-1alpha in epidermis displayed a 66% increase in dermal capillaries, a 13-fold elevation of total vascular endothelial growth factor (VEGF) expression, and a six- to ninefold induction of each VEGF isoform. Despite marked induction of hypervascularity, HIF-1alpha did not induce edema, inflammation, or vascular leakage, phenotypes developing in transgenic mice overexpressing VEGF cDNA in skin. Remarkably, blood vessel leakage resistance induced by HIF-1alpha overexpression was not caused by up-regulation of angiopoietin-1 or angiopoietin-2. Hypervascularity induced by HIF-1alpha could improve therapy of tissue ischemia.

Coordinate up-regulation of hypoxia inducible factor (HIF)-1alpha and HIF-1 target genes during multi-stage epidermal carcinogenesis and wound healing

Both carcinogenesis and wound healing proceed through stages of proliferation and tissue remodeling. Here, using either a model of multistage epidermal carcinogenesis in K14-HPV16 transgenic mice or creation of full-thickness back wounds in nontransgenic mice, we determined patterns of expression of hypoxia inducible factor (HIF)-1alpha, and three targets of the heterodimeric transcription factor HIF-1, glucose transporter (GLUT)-1, phosphoglycerate kinase (PGK)-1, and vascular endothelial growth factor (VEGF) in skin. Neither HIF-1alpha, GLUT-1, PGK-1, nor VEGF mRNA was detectable in unwounded nontransgenic skin. In epidermal carcinogenesis, HIF-1alpha, GLUT-1, PGK-1, and VEGF mRNAs were just detectable in early-stage hyperplasia, markedly increased in high-grade epidermal chest dysplasias, and further increased in invasive squamous carcinomas. In neoplastic skin, HIF-1alpha, GLUT-1, and PGK-1 mRNAs localized in the basal and immediate suprabasal epidermal layers, whereas VEGF mRNA was predominantly expressed in the more superior spinous and granular epidermal layers. Immediately after wounding, HIF-1alpha, GLUT-1, and PGK-1 mRNAs were detectable in basal keratinocytes at the wound edge. Expression of all three genes increased to maximum levels in reepithelializing basal keratinocytes and then diminished to near undetectable levels after wound epithelialization. Although VEGF mRNA similarly increased and decreased during wound healing, its expression pattern was more punctate; the most intense hybridization signals were detected in the upper spinous and granular layers of reepithelializing keratinocytes and in dermal cells morphologically similar to macrophages. These data suggest stage-specific and spatio-temporal control of HIF-1alpha and HIF-1 target gene expression in both multistage epithelial carcinogenesis and wound healing.

Hypoxia-inducible factor-1alpha is a positive factor in solid tumor growth

Deficiencies in oxygenation are widespread in solid tumors. The transcription factor hypoxia-inducible factor (HIF)-1alpha is an important mediator of the hypoxic response of tumor cells and controls the up-regulation of a number of factors important for solid tumor expansion, including the angiogenic factor vascular endothelial growth factor (VEGF). We have isolated two cell lines nullizygous for HIF-1alpha, one from embryos genetically null for HIF-1alpha, and the other from embryos carrying loxP-flanked alleles of the gene, which allows for cre-mediated excision. The loss of HIF-1alpha negatively affects tumor growth in these two sets of H-ras-transformed cell lines, and this negative effect is not due to deficient vascularization. Despite differences in VEGF expression, vascular density is similar in wild-type and HIF-1alpha-null tumors. The evidence from these experiments indicates that hypoxic response via HIF-1alpha is an important positive factor in solid tumor growth and that HIF-1alpha affects tumor expansion in ways unrelated to its regulation of VEGF expression.

Sensitivity of the cervical transformation zone to estrogen-induced squamous carcinogenesis

Regions where one type of epithelium replaces another (metaplasia) have a predilection for cancer formation. Environmental factors are closely linked to metaplastic carcinogenesis. In particular, cervical cancers associated with human papillomavirus (HPV) infection develop primarily at the transformation zone, a region where metaplastic squamous cells are detected in otherwise columnar epithelial-lined endocervical glands. Previously, we reported estrogen-induced multistage vaginal and cervical carcinogenesis in transgenic mice expressing HPV16 oncogenes in basal squamous epithelial cells. In the present study to investigate the threshold neoplastic response to exogenous estrogen, we treated groups of transgenic mice with lower hormone doses. A 5-fold reduction in estrogen dose induced squamous carcinogenesis solely at the cervical transformation zone compared with other reproductive tract sites. Further study delineated stages of transformation zone carcinogenesis, including formation of hyperplastic lower uterine glands and emergence of multiple foci of squamous metaplasia from individual stem-like glandular reserve cells, followed by neoplastic progression of metaplasia to dysplasia and squamous cancer. We propose that a combination of low-dose estrogen and low-level HPV oncogene expression biases transformation zone glandular reserve cells toward squamous rather than columnar epithelial fate decisions. Synergistic activation of proliferation by viral oncoprotein cell cycle dysregulation and estrogen receptor signaling, together with altered paracrine stromal-epithelial interactions, may conspire to support and promote neoplastic progression and cancer formation.

Indole-3-carbinol prevents cervical cancer in human papilloma virus type 16 (HPV16) transgenic mice

Mice that express transgenes for human papillomavirus type 16 under a keratin 14 promoter (K14-HPV16 mice) develop cervical cancer when they are given 17beta-estradiol chronically. We asked whether the antiestrogenic phytochemical indole-3-carbinol (I3C), found in cruciferous vegetables, administered at physiological doses, would prevent the cervical-vaginal cancer that is promoted in these mice by high doses of estrogen. We compared mice that were fed a control diet with those that were fed a diet supplemented with 2000 ppm I3C. In the group fed the control diet, at a dose of estradiol of 0.125 mg per 60-day release, 19 of 25 transgenic mice developed cervical-vaginal cancer within 6 months, and the remainder had dysplasia. Only 2 mice of 24 in the group fed the I3C supplemented diet developed cancer, and the remainder had dysplasia or hyperplasia. I3C reduced dysplasia in the nontransgenic mice. Similar results were obtained at a higher dose of estradiol (0.250 mg per 60-day release), and I3C helped to prevent morbidity associated with retention of fluid in the bladder that frequently occurred with the higher estradiol dose. Additionally, I3C appeared to reduce skin cancer in transgenic mice. These data indicate that I3C is a useful preventive for cervical-vaginal cancer and, possibly, other cancers with a papillomavirus component.

Difluoromethylornithine chemoprevention of epidermal carcinogenesis in K14-HPV16 transgenic mice

To be informative for chemoprevention, animal models must both closely emulate human disease and possess surrogate endpoint biomarkers that facilitate rapid drug screening. This study elucidated site-specific histopathological and biochemical surrogate endpoint biomarkers of spontaneous epidermal carcinogenesis in K14-HPV16 transgenic mice and demonstrated that the incidence and severity of these markers were decreased by the ornithine decarboxylase (ODC) inhibitor difluoromethylornithine (DFMO). The cumulative incidence of visible epidermal cancers in 127 untreated transgenic mice was 42% by 52 weeks of age, most frequently affecting the chest as flat lesions in association with chronic ulcers, or in the ear as protuberant masses. Microscopic malignancies were detected in 39% of 32-week-old transgenic mice and were found to emerge from precursor lesions that were of two distinct types: dysplastic sessile ear papillomas and hyperproliferative follicular/interfollicular chest dysplasias. ODC activity and tissue polyamine contents were differentially elevated in ear and chest skin during carcinogenesis, such that there was a marked elevation of both parameters of polyamine metabolism as early as 4 weeks of age in the ear, whereas in the chest, polyamine metabolism was increased significantly only in the late stages of neoplastic progression and in epidermal cancers. Administration of 1.0% DFMO in the drinking water from 4 to 32 weeks of age prevented both visible and microscopic malignancies and significantly decreased the incidence of chest and ear precursor lesions. ODC activity and tissue putrescine content were markedly diminished by DFMO chemoprevention in ear skin, whereas there was a more modest decline of these parameters in chest skin. DFMO treatment of transgenic mice from 28 to 32 weeks of age was associated with an absence of ear cancer and a marked regression of dysplastic papillomas. In contrast, the results in chest skin were complex in that the severity of chest precursors diminished, but their incidence was unchanged, and microscopic cancers were still detectable within these lesions. Collectively, this study highlights the utility of multistage epidermal carcinogenesis in K14-HPV16 transgenic mice both for the study of the biology of, and as a screening tool for, novel drugs and chemopreventive regimens.

Expression of interferon-beta is associated with growth arrest of murine and human epidermal cells

The cytokine interferon-beta is a regulator of cell replication and function, including invasion and induction of angiogenesis. The goal of this study was to determine whether the expression of interferon-beta by cells in the epidermis correlated with terminal differentiation. In situ hybridization analysis and immunohistochemical staining of formalin-fixed, paraffin-embedded specimens of normal human and murine epidermis and human and murine skin tumors of epithelial origin revealed that only differentiated, nondividing cells of the epidermis expressed interferon-beta protein. Keratinocyte cultures established from the epidermis of 3 d old mice were maintained under conditions permitting continuous cell division or induction of differentiation. Continuously dividing cells did not produce interferon-beta whereas nondividing differentiated cells expressing keratin 1 did. Growth-arrested, undifferentiated keratinocytes also expressed interferon-beta protein. Neutralizing interferon-beta in the culture medium inhibited differentiation, but the addition of exogenous interferon-beta did not stimulate differentiation. These data indicate that interferon-beta is produced by growth-arrested, terminally differentiated keratinocytes.

Murine mentors: transgenic and knockout models of surgical disease

OBJECTIVE

Transgenic and knockout technologies have emerged from the "molecular biology revolution" as unprecedented techniques for manipulating gene function in intact mice. The goals of this review are to outline the techniques of creating transgenic and knockout mice, and to demonstrate their use in elucidation of the molecular mechanisms underlying common surgical diseases.

SUMMARY BACKGROUND DATA

Gain of gene function is created by transgenic technology, whereas gene function is ablated using gene knockouts. Each technique has distinctive applications and drawbacks. A unique feature of genetically manipulated mice is that combinatorial genetic experiments can be executed that precisely define the functional contribution of a gene to disease progression. Transgenic and knockout mouse models of wound healing, cardiovascular disease, transplant immunology, gut motility and inflammatory bowel disease, and oncology are beginning to illuminate the precise molecular regulation of these diseases. Transgenic technology has also been extended to larger mammals such as pigs, with the goal of using genetic manipulation of the xenogenic immune response to increase the availability of transplant organs. Continual refinements in gene manipulation technology in mice offer the opportunity to turn genes on or off at precise time intervals and in particular tissues, according to the needs of the investigator. Ultimately, investigation of disease development and progression in genetically manipulated mammals may delineate new molecular targets for drug discovery and provide novel platforms for drug efficacy screens.

CONCLUSIONS

Emulation of human disease and therapy using genetically manipulated mammals fulfills a promise of molecular medicine: fusion of molecular biochemistry with "classical" biology and physiology. Surgeons have unique skills spanning both worlds that can facilitate their success in this expanding arena.

Human acellular dermal matrix as a novel model of malignant epithelial cell invasion

Cancer invasion and metastasis are associated with matrix degradation. We describe a novel in vivo model of invasion by squamous epithelial neoplastic cells derived from transgenic mice grown on acellular human dermis. Human dermis was subjected to multiple freeze-thaw cycles to render it acellular, maintaining the basement membrane of the former dermal-epidermal junction. Cells representing discrete stages of a multistep transgenic mouse model of epidermal carcinogenesis (neonatal transgenic keratinocytes, moderately/poorly differentiated squamous cell carcinoma, and lymph node metastasis) were seeded onto the basement membrane surface, grown in culture for 4 days, grafted in a subpannicular pocket of athymic mice, and harvested after 3 weeks. Histological analysis demonstrated that neonatal transgenic keratinocytes did not degrade the basement membrane or invade the underlying dermis. In contrast, malignant cells derived from both a moderately differentiated squamous carcinoma and a lymph node metastasis were highly invasive. Immunohistochemical analysis revealed collagenase only in nests of invading malignant cells in contact with the dermal matrix, but not in the tumor mass remaining above the basement membrane, suggesting that this proteinase may be required for stromal invasion. This novel model recapitulates the events seen in malignant invasion: transgenic keratinocytes are unable to penetrate the dermis while cells from a moderately differentiated carcinoma and from lymph node metastasis consistently invade.

Genetic predisposition and parameters of malignant progression in K14-HPV16 transgenic mice

Reproducible multi-stage progression to invasive squamous carcinoma of the epidermis has been achieved in transgenic mice expressing the HPV16 early-region genes, including the E6/E7 oncogenes, under the control of the human keratin-14 promoter/enhancer. Although 100% of K14-HPV16 transgenic animals develop hyperplastic and/or dysplastic lesions in several inbred backgrounds, including C57BL/6, BALB/c, and SSIN/SENCAR, only mice backcrossed into the FVB/n background progress to malignant squamous cell carcinomas of two pathological grades, well differentiated and moderate/poorly differentiated (WDSC or MPDSC, respectively), each displaying characteristic patterns of malignant behavior. WDSCs typically arise within the epidermis of the ear and invade deeply into the underlying dermis but fail to metastasize, whereas MPDSCs develop on the chest and truncal skin and invariably metastasize to regional lymph nodes. The transition to the malignant state, in 21% of FVB/n transgenic mice, is characterized by alteration of the repertoire of keratin intermediate filament proteins expressed within neoplastic epidermis, such that WDSCs maintain expression of keratins common to terminally differentiating stratified keratinocytes (K10), whereas MPDSCs are distinguished from WDSCs by activation of embryonic and mucosal keratins (K13, K8, and K19). Precursor hyperplastic and dysplastic lesions are characterized by a progressively increased proliferative index, striking morphological alterations in keratinocyte cell-cell and cell-matrix interactions, and extensive remodeling of the underlying dermal stroma. Remarkably, this extensive stromal remodeling, which may facilitate both angiogenesis and eventual tumor cell invasion, develops early at the dysplastic stage in all animals well before malignant conversion.

Upregulation of fibroblast growth factors and their receptors during multi-stage epidermal carcinogenesis in K14-HPV16 transgenic mice

Upregulation of acidic and basic fibroblast growth factors (FGF-1 and -2), and their cognate receptors FGFR-1 and -2, has been demonstrated in a variety of epithelial malignancies. However, the patterns of FGF/FGFR expression at specific stages of epithelial carcinogenesis have not been extensively characterized. In this report, the levels of FGF-1, FGF-2, FGF-7 mRNA and their receptors FGFR-1 and FGFR-2, were investigated during epidermal carcinogenesis in transgenic mice expressing the early region of the 'high risk' papillomavirus type 16 (HPV16) under control of the human keratin-14 enhancer/promoter (K14-HPV16 transgenic mice). FGF-1 was first upregulated in dysplasias, while FGF-2 was constitutively expressed in non-transgenic, neoplastic, and malignant keratinocytes throughout carcinogenesis. Expression of FGF-7 was undetectable in non-transgenic epidermis, and remained at threshold levels at all stages of progression. In well differentiated squamous cancers, FGFR-1 was upregulated and co-localized with angiogenic capillaries in the dermis underlying dysplastic lesions and within papillary fronds of invasive cancers. In contrast, FGFR-1 was upregulated specifically within the malignant squamous cells of moderate-poorly differentiated squamous cancers. The expression of FGFR-2 was essentially constitutive in both non-transgenic and neoplastic epidermis. Collectively the data suggest that the FGF/FGFR signaling pathways may potentially contribute to several facets of multi-stage epithelial carcinogenesis, including auto- or paracrine growth stimulation, upregulation of angiogenesis, and stromal remodeling.

Chronic estrogen-induced cervical and vaginal squamous carcinogenesis in human papillomavirus type 16 transgenic mice

High-risk human papillomaviruses (HPVs), including type 16, have been identified as factors in cervical carcinogenesis. However, the presence and expression of the virus per se appear to be insufficient for carcinogenesis. Rather, cofactors most likely are necessary in addition to viral gene expression to initiate neoplasia. One candidate cofactor is prolonged exposure to sex hormones. To examine the possible effects of estrogen on HPV-associated neoplasia, we treated transgenic mice expressing the oncogenes of HPV16 under control of the human keratin-14 promoter (K14-HPV16 transgenic mice) and nontransgenic control mice with slow release pellets of 17beta-estradiol. Squamous carcinomas developed in a multistage pathway exclusively in the vagina and cervix of K14-HPV16 transgenic mice. Estrogen-induced carcinogenesis was accompanied by an incremental increase in the incidence and distribution of proliferating cells solely within the cervical and vaginal squamous epithelium of K14-HPV16 mice. Expression of the HPV transgenes in untreated transgenic mice was detectable only during estrus; estrogen treatment resulted in transgene expression that was persistent but not further upregulated, remaining at low levels at all stages of carcinogenesis. The data demonstrate a novel mechanism of synergistic cooperation between chronic estrogen exposure and the oncogenes of HPV16 that coordinates squamous carcinogenesis in the female reproductive tract of K14-HPV16 transgenic mice.

Regulation of Myc and Mad during epidermal differentiation and HPV-associated tumorigenesis

c-Myc and Mad each form heterodimers with Max that bind the same E-box related DNA sequences. Whereas Myc:Max complexes activate transcription and promote cell proliferation and transformation, Mad:Max complexes repress transcription and block c-Myc-mediated cell transformation. Here we examine these antagonistic transcription factors during epithelial differentiation and neoplastic progression. During differentiation of primary human keratinocytes, Mad is rapidly induced and c-Myc is downregulated, resulting in a switch from c-Myc:Max to Mad:Max heterodimers. In normal epidermis and colonic mucosa c-myc expression is restricted to proliferating cell layers, while mad expression is restricted to differentiating cell layers. Using HPV18 transformed keratinocytes that vary in their ability to differentiate in organotypic cultures, we find that Mad induction occurs only in those cells that retain a differentiation response. In the epidermis of transgenic mice in which expression of the HPV16 E6 and E7 oncogenes are targeted to basal keratinocytes, neoplastic progression occurs and is marked by an expansion of c-myc expressing basal-like cells. Expression of mad is found only in growth-arrested differentiating cells on the outer edges of preneoplastic lesions. The squamous cell carcinomas that arise evidence a variable number of sites within the tumor masses where mad expression and morphological differentiation coincide; increasing malignancy correlates with loss of both mad and capability to differentiate. These results indicate that c-Myc and Mad expression are tightly coupled to the transition from proliferation to differentiation of epithelial cells and that restriction of Mad expression may be associated with loss of normal differentiation capability and with tumorigenesis.

Limited capacity for tolerization of CD4+ T cells specific for a pancreatic beta cell neo-antigen

Mice transgenic for SV40 T antigen (Tag) under control of the rat insulin promoter (RIP) develop two alternative immunological phenotypes: tolerance or autoimmunity towards Tag. We utilized the T cell receptor (TCR) genes expressed in a Tag-specific CD4+ cell from an autoimmune RIP-Tag mouse to generate two lines of TCR transgenic mice in which either 10% or 90% of peripheral T cells express the transgenic TCR. When cross-bred to the tolerant RIP1-Tag2 line, mice from the low frequency TCR line showed partial deletion of peripheral Tag-specific T cells and nonresponsiveness of those that remained. In contrast, crossbred mice in which transgenic T cells comprised a majority of the T cell population were nontolerant both in vivo and in vitro. Thus, tolerization of CD4+ T cells specific for a rare self-antigen may fail if too many autoreactive T cells develop.

Progressive squamous epithelial neoplasia in K14-human papillomavirus type 16 transgenic mice

To model human papillomavirus-induced neoplastic progression, expression of the early region of human papillomavirus type 16 (HPV16) was targeted to the basal cells of the squamous epithelium in transgenic mice, using a human keratin 14 (K14) enhancer/promoter. Twenty-one transgenic founder mice were produced, and eight lines carrying either wild-type or mutant HPV16 early regions that did not express the E1 or E2 genes were established. As is characteristic of human cancers, the E6 and E7 genes remained intact in these mutants. The absence of E1 or E2 function did not influence the severity of the phenotype that eventually developed in the transgenic mice. Hyperplasia, papillomatosis, and dysplasia appeared at multiple epidermal and squamous mucosal sites, including ear and truncal skin, face, snout and eyelids, and anus. The ears were the most consistently affected site, with pathology being present in all lines with 100% penetrance. This phenotype also progressed through discernible stages. An initial mild hyperplasia was followed by hyperplasia, which further progressed to dysplasia and papillomatosis. During histopathological progression, there was an incremental increase in cellular DNA synthesis, determined by 5-bromo-2'-deoxyuridine incorporation, and a profound perturbation in keratinocyte terminal differentiation, as revealed by immunohistochemistry to K5, K14, and K10 and filaggrin. These K14-HPV16 transgenic mice present an opportunity to study the role of the HPV16 oncogenes in the neoplastic progression of squamous epithelium and provide a model with which to identify genetic and epigenetic factors necessary for carcinogenesis.

Neuroepithelial carcinomas in mice transgenic with human papillomavirus type 16 E6/E7 ORFs

The effect of the human papillomavirus (HPV) oncogenes E6 and E7 was examined in transgenic mice with a construct containing the human beta-actin promoter regulating HPV16 E6 and E7 open reading frames. In the sole line of mice that transmitted the transgene, neuroepithelial tumors appeared at 2.5 months of life, and by 10 months, 87 of 122 (71%) of the animals were dead from brain tumors. The most frequent type of tumor (74%) was an anaplastic neuroepithelial tumor associated with the ependyma of the third and fourth ventricles, which locally invaded adjacent brain tissue and spread for considerable distances along the ventricular surface. The other two types of tumor were well-differentiated choroid plexus carcinomas (26%) and rare pituitary carcinomas (8.7%). HPV16 E6 RNA and E7 oncoprotein expression were demonstrated in tumor tissue and primary cell lines derived from the tumors. Examination of two tumor suppressor gene products, the retinoblastoma protein and p53, known to bind to HPV16 E7 and E6 oncoproteins, respectively, showed both were expressed in the primary tumor cell lines. These data support a causative role for the HPV oncoproteins in epithelial carcinogenesis.

Selective depletion of tumor ATP by 2-deoxyglucose and insulin, detected by 31P magnetic resonance spectroscopy

The purpose of this study was to investigate whether substrate deprivation acutely and selectively decreases ATP concentration in an experimental sarcoma. Two methods of substrate deprivation were examined: glycolysis was inhibited using 2-deoxyglucose (2DG), and plasma substrate levels were reduced using insulin. The effects of treatment on tumor ATP, inorganic phosphate, and pH were studied by 31P nuclear magnetic resonance spectroscopy. 2DG (2 g/kg) was administered i.p. to rats bearing s.c. methylcholanthrene-induced sarcomas. Inhibition of glycolysis by 2DG caused a 52 +/- 13% (SE) decrease in the tumor ATP to inorganic phosphate ratio, associated with a decrease in pH of 0.38 +/- 0.10 unit. The same dose of 2DG caused no significant change in the ratio of phosphocreatine to ATP in brain. Insulin (125 units/kg, i.p.) caused a 68% decline in plasma glucose and a 71% decline in betahydroxybutyrate compared to saline-treated animals. Concomitantly, 31P nuclear magnetic resonance spectroscopy detected a 48 +/- 13% decrease in sarcoma ATP, with a reciprocal elevation of inorganic phosphate in insulin-treated animals. In contrast, the brain phosphocratine/ATP ratio was unaffected by insulin. These results suggest that large tumors are acutely sensitive to inhibition of glycolysis and reductions in plasma levels of substrates for oxidative phosphorylation and glycolysis, while the brain is unaffected. In addition, this work provides support for the use of 31P nuclear magnetic resonance spectroscopy to monitor tumor response to therapy.

Molecules, cancer, and the surgeon. A review of molecular biology and its implications for surgical oncology

Interactions between molecules control intra- and intercellular physiology. Cancer is emerging as a disease in which individual molecules are either overproduced, mutated, expressed at inappropriate stages of development, or lost due to inheritance or aberrant mitotic division. The major players in this contest of cellular control are growth factors, growth factor receptors (GFRs), signal transducers, and dominant or suppressor/recessive oncogenes. The tumors most frequently removed by surgeons have been reported to have changes in one or another of these types of molecules. The concept of multistage carcinogenesis, whereby malignancy arises after a sequence of changes that are cumulative, and passed from progenitor to daughter cells, is also being defined as a sequence of molecular, genetic, and chromosomal alterations. Molecular antineoplastic therapy is in early stages of development at the laboratory bench. The future may see patients screened for cancer susceptibility, evaluated for adjuvant therapy, and chosen for particular treatment based on molecular analysis. The types of cancer operations and the scope of surgical resection may change as molecular techniques enhance oncologic treatment.

Inhibition of tumor high-energy phosphate metabolism by insulin combined with rhodamine 123

The purpose of this study was to determine whether the energy metabolism of an experimental rodent sarcoma was selectively depressed by the combination of inhibition of glycolysis and respiration. In vivo phosphorus-31 nuclear magnetic resonance spectroscopy was used to monitor the response of tumor or brain high-energy phosphate compounds to insulin hypoglycemia, rhodamine 123, or both agents in fasting rats with subcutaneous methylcholanthrene-induced sarcomas. Insulin or rhodamine 123 alone produced a similar 50% to 60% reduction in tumor adenosine triphosphate (ATP) concentration compared with controls injected with saline solution (p less than 0.05, one-way analysis of variance [ANOVA]). The combination of insulin plus rhodamine 123 resulted in a 90% reduction of tumor ATP concentration, which was significantly different from the effect of either agent alone (p less than 0.05, one-way ANOVA). Brain phosphocreatine and ATP concentrations were unchanged by these agents. Administration of dimethyl sulfoxide (DMSO)/glycerol, the vehicle for rhodamine, produced a 35% reduction of tumor ATP, which was similar to the effect of insulin alone but significantly different from rhodamine. The combination of DMSO/glycerol plus insulin hypoglycemia resulted in a 70% reduction in tumor ATP, which was significantly elevated compared with the combination of rhodamine plus insulin. Glucose deprivation induced by insulin, and combined with the inhibition of oxidative phosphorylation, produces an additive depression of tumor energetics. The drug vehicle DMSO/glycerol significantly depresses tumor energy metabolism, presumably because of its DMSO component, which may explain the previously reported antineoplastic efficacy of this solvent. Combinations of inhibitors directed at different points of tumor metabolism produced an enhanced depression of tumor energetics, whereas host tissue was protected.

Wound complications in the multimodality treatment of extremity and superficial truncal sarcomas

The incidence and severity of wound complications were examined in 105 patients with extremity and superficial truncal sarcomas who were eligible for wide local excision with or without adjuvant perioperative brachytherapy (BRT) and/or chemotherapy. Fifty-four cases from the eligible group were entered into a randomized prospective trial of the efficacy of BRT in decreasing local recurrence. In the eligible patients, major wound complications occurred in nine of 41 (22%) of the BRT cases, compared with two of 64 (3%) of the non-BRT patients, which was a significant increase (P = .002). The combined frequency of major and moderate wound complications was also significantly increased in the BRT (18 of 41, 44%) compared with the non-BRT (nine of 64, 14%) patients (P = .0006). The median duration to complete resolution of these complications was 189 days (14 to 597) in the BRT, compared with 49 (11 to 170) days in the non-BRT group (P = .0005); however, no amputations were required, and only 14% of the BRT-associated wound complications were of prolonged duration, ie, greater than 200 days. In the randomized study, both the total number of complications, and the combination of major and moderate complications were increased significantly in the BRT v the non-BRT patients. Adjuvant Adriamycin (Adria Laboratories, Columbus, OH) administered in 60 mg/m2 increments to a cumulative dose of 540 mg/m2 did not appear to impair wound healing even when administered within 15 days of operation. Significant wound complications occur in major resections of extremity and superficial truncal sarcomas. If the addition of adjuvant BRT produces a decrease in local recurrence, then either patient selection will have to be more rigidly applied, especially in wounds where skin flap blood supply is tenuous, or the technique will need to be modified to balance the short-term aim of reducing wound complications with the long-term goal of local tumor control.

Basal amino acid concentrations and the response to incremental glucose infusion in tumor bearing rats

Plasma amino acid concentrations were measured in fasting nontumor bearing (NTB) and tumor bearing (TB; methylcholanthrene induced sarcoma) male Fischer F344 rats during infusion of 0.9% NaCl solution or glucose at 3.72 or 13.05 mumol/100 g total body weight (TBW)/min. The animals were studied when the tumor comprised only 8% of the TBW at a time when decreased food intake and weight loss were not manifest. During 0.9% NaCl infusion there were no significant differences between NTB or TB animals in the concentration of alanine (NTB: 152.6 +/- 20.1; TB: 150.3 +/- 19.0 microM; mean +/- SD), branched chain amino acids (BCAA) (NTB: 343.3 +/- 48.7; TB: 344.2 +/- 20.5 microM), essential amino acids, aromatic amino acids, or total amino acids. During infusion of glucose at 3.72 mumol/100 g TBW/min the alanine levels rose (NTB: 283.6 +/- 33.4; TB: 286.7 +/- 43.3 microM), and the BCAA levels fell (NTB: 215.9 +/- 19.4; TB: 228.7 +/- 43.4 microM) to similar concentrations in both NTB and TB animals. Glucose infusion at 13.05 mumol/100 g TBW/min resulted in an additional increase in the alanine concentration (NTB: 344.5 +/- 28.7; TB: 382.8 +/- 116.6 microM), and a further decrease in the BCAA concentration (NTB: 166.4 +/- 30.8; TB: 160.7 +/- 30.5 microM) without significant differences between NTB and TB animals. Paired analysis for each animal prior to and during glucose infusion demonstrated a similar absolute micromolar change in alanine and BCAA concentration during both glucose infusion rates in both NTB and TB animals. The levels of aromatic amino acids and total amino acids were unchanged and the essential amino acid concentrations were decreased only at the higher glucose infusion rate in both NTB and TB groups. Basal amino acid metabolism appears similar in the NTB and TB animals, prior to the onset of anorexia and weight loss. During exogenous glucose infusion the reciprocal changes in the plasma alanine and BCAA concentrations support the concept of a glucose-alanine-BCAA cycle at the whole body level that appears to respond to a similar extent in NTB and TB animals.

Resting energy expenditure in controls and cancer patients with localized and diffuse disease

Resting energy expenditure (REE), nutritional parameters, and substrate levels were measured using a technique to minimize artifacts in 11 control patients, nine patients with localized, and four patients with diffuse neoplastic disease. Patients with diffuse disease had significantly increased percentage preillness weight loss (15.4 +/- 7.0%), decreased arm muscle circumference (21.9 +/- 2.1 vs. 26.2 +/- 3.5 cm), serum albumin (3.6 +/- 0.6 vs. 4.4 +/- 0.2 g/dl), total lymphocyte count (1024 +/- 613 vs. 1796 +/- 495 cells/mm3), and creatinine-height index (0.68 +/- 0.16 vs. 1.18 +/- 0.37) compared to controls. Both groups of cancer patients had significantly increased REE compared to controls: 25.6 +/- 3.7 (diffuse), 21.4 +/- 3.7 (localized), vs. 18.1 +/- 2.9 kcal/kg/d (controls). However, when REE was expressed as a function of metabolic body size, the significant difference persisted only in the patients with diffuse disease compared to controls: 71.8 +/- 16.4 vs. 53.9 +/- 8.1 kcal/kg3/4/d. Patients studied pre- and posttumor resection all had a postoperative drop in their REE, which was significantly correlated with the measured tumor volume. In this homogeneous, select group of patients, the tumor-bearing state exerts a moderate impact on nutritional and metabolic parameters, which are probably related to the extent of disease.

Glucose metabolism and the percentage of glucose derived from alanine: response to exogenous glucose infusion in tumor-bearing and non-tumor-bearing rats

Glucose and alanine metabolism were investigated in non-tumor-bearing (NTB) and tumor-bearing (TB) male F344 rats after a 24-hr fast and during the infusion of either 0.9% NaCl solution or glucose at 0.67 or 2.35 mg per 100 g total body weight per min. During 0.9% NaCl solution infusion, the plasma glucose level was higher (98.2 +/- 4.0 versus 85.8 +/- 8.1 mg per di; p less than 0.05), the whole-blood lactate level was lower (5.8 +/- 0.8 versus 8.3 +/- 1.6 mg per di; p less than 0.05), the glucose turnover rate was lower (0.72 +/- 0.04 versus 0.88 +/- 0.13 mg per 100 g total body weight per min; p less than 0.05), alanine turnover rate and the percentage of glucose derived from alanine was measured by [14C]alanine in the NTB and compared to the TB animals. In response to glucose infusions, the whole-blood lactate level rose in both groups but remained lower (7.1 +/- 0.9 versus 10.5 +/- 2.4 mg per dl at 0.67 mg per 100 g total body weight per min, p less than 0.05; 9.1 +/- 1.1 versus 19.3 +/- 5.5 mg per dl at 2.35 mg per 100 g total body weight per min, p less than 0.05; NTB versus TB) in the NTB than in the TB animals. The endogenous production rate of glucose as measured by [3H]glucose displayed a similar response to exogenous substrate in the NTB and TB animals but required a higher plasma glucose concentration to effect a similar degree of suppression in the TB group. The alanine turnover rate rose to a similar level, and the percentage of glucose derived from alanine was similarly depressed in the NTB and TB animals at each glucose infusion rate.

Deep venous thromboembolism in patients undergoing inguinal lymph node dissection for melanoma

Deep venous thromboembolism (DVT) was studied in 44 patients with clinical Stage I, II, and III melanoma undergoing staging and therapeutic inguinal lymph node dissection. The ability of two noninvasive methods of surveillance, the phleborheograph (PRG) and the 125I fibrinogen scan to detect deep venous thrombosis was determined by comparison with prospective bilateral lower extremity venograms. In addition, the therapeutic impact, both beneficial and detrimental, of low dose heparin, 5000 units administered subcutaneously two hours prior to and every eight hours after operation was determined in a double blind study. The sensitivity of the PRG and 125I fibrinogen scan were both 20%. There were five deep venous thrombi, and two pulmonary emboli for a combined incidence of DVT of 13.6% for the entire patient population. However, there was no significant difference in the incidence of DVT between the two groups. The heparin-treated patients had an increased total volume (796 +/- 516 versus 388 +/- 208 ml; p less than 0.05), and duration of wound drainage (9 +/- 4 versus 13 +/- 6 days; p less than 0.05).

Latent pulmonary embolus from a retroperitoneal sarcoma

A 52-year-old female presented with an extensive retroperitoneal sarcoma and intraluminal inferior vena caval extension. Presumably during resection, embolization of a tumor fragment occurred to the right pulmonary hilum. The patient was asymptomatic for 16 months until a right hilar mass developed on a follow-up chest x-ray. Pathological examination of the gross and microscopic sections of the pneumonectomy specimen confirmed the intra-arterial location of the tumor mass. Widespread systemic metastasis became evident soon after pneumonectomy.

Mucoepidermoid tumor of trachea

Mucoepidermoid carcinoma of the trachea is rare. Its occurence in a 14-year-old boy is reported here. This case illustrates the typical course of tracheal tumors with clinical manifestations of cough, wheezing, and hemoptysis, the intially reported normal chest roentgenogram, and the common failure to diagnose tracheal tumor for several months. Early use of tomographic studies and bronchoscopic examination in any person with recent onset of airway obstruction unresponsive to bronchodilator therapy is recommended.