The Use of a Commercial ELISA for Assay of Thrombin-Antithrombin Complexes in Purified Systems

Inhibition of thrombin by antithrombin III (AT) results in the formation of stable thrombin-AT complexes (TAT). An enzyme-linked immunosorbent assay (ELISA) following the sandwich principle is available for the determination of TAT complexes in human plasma, however, this ELISA method could not be used in purified systems containing thrombin and AT. It has therefore been modified for use in purified systems and an excellent correlation was found between the disappearance of thrombin and AT and the recovery of TAT complexes. Addition of thrombin inhibitor hirudin and heparin inhibitor polybrene into the reacting thrombin-AT mixture did not interfere with the assay of TAT. It was found that the use of siliconised tubes was necessary for the conservation of the TAT complexes.

Antithrombin III Binding to Surface Immobilized Heparin and Its Relation to F Xa Inhibition

The mode of F Xa inhibition was investigated on a thromboresistant surface with end-point attached partially depoly-merized heparin of an approximate molecular weight of 8000. Affinity chromatography revealed that one fourth of the heparin used in surface coating had high affinity for antithrombin III (AT). The heparin surface adsorbed AT from both human plasma and solutions of purified AT. By increasing the ionic strength in the AT solution the existence of high and low affinity sites could be shown. The uptake of AT was measured and the density of available high and low affinity sites was found to be in the range of 5 HTid 11 pic.omoles/cmf, respectively Thus the estimated density of biologically active high and low ailmity heparm respectively would be 40 and 90 ng/cm2 The heparin coating did not take up or exert F Xa inhibition by itself. With AT adsorbed on both high and low affinity heparin the surface had the capacity to inhibit several consecutive aliquots of F Xa exposed to the surface. When mainly high affinity sites were saturated with AT the inhibition capacity was considerably lower. Tt was demonstrated that the density of AT on both high and low affinity heparin determines the F Xa inhibition capacity whereas the amount of AT on high affinity sites limits the rate of the reaction. This implies that during the inhibition of F Xa there is a continuous surface-diffusion of AT from sites of a lower class to the high affinity sites where the F Xa/AT complex is formed and leaves the surface. The ability of the immobilized heparin to catalyze inhibition of F Xa is likely to be an important component for the thromboresistant properties of a heparin coating with non-compromized AT binding sequences.

Selecting patients for cytotoxic therapies in gastroenteropancreatic neuroendocrine tumours

Gastroenteropancreatic neuroendocrine tumours (GEP-NET) have heterogenic clinical presentations. The majority of GEP-NET tumours have an indolent behaviour, but patients will eventually develop symptoms of tumour progression or hormone secretion that may require systemic medical interventions. Cytotoxic chemotherapy has been tested in GEP-NETs since the 80s, but treatment recommendations are controversial in many instances. Patient selection is mandatory for optimal use of chemotherapy. Important prognostic factors such as primary tumour site, tumour differentiation, tumour staging and proliferation index have been identified and validated in retrospective and prospective series. The combination of those factors and the natural history of GEP-NET provide valuable information with respect to treatment planning. In this report we provide treatment recommendations to improve systemic therapy in patients with advanced GEP-NETs based on a comprehensive review of the literature.

Cancer cell proliferation is inhibited by specific modulation frequencies

Background:

There is clinical evidence that very low and safe levels of amplitude-modulated electromagnetic fields administered via an intrabuccal spoon-shaped probe may elicit therapeutic responses in patients with cancer. However, there is no known mechanism explaining the anti-proliferative effect of very low intensity electromagnetic fields.

Methods:

To understand the mechanism of this novel approach, hepatocellular carcinoma (HCC) cells were exposed to 27.12 MHz radiofrequency electromagnetic fields using in vitro exposure systems designed to replicate in vivo conditions. Cancer cells were exposed to tumour-specific modulation frequencies, previously identified by biofeedback methods in patients with a diagnosis of cancer. Control modulation frequencies consisted of randomly chosen modulation frequencies within the same 100 Hz–21 kHz range as cancer-specific frequencies.

Results:

The growth of HCC and breast cancer cells was significantly decreased by HCC-specific and breast cancer-specific modulation frequencies, respectively. However, the same frequencies did not affect proliferation of nonmalignant hepatocytes or breast epithelial cells. Inhibition of HCC cell proliferation was associated with downregulation of XCL2 and PLP2. Furthermore, HCC-specific modulation frequencies disrupted the mitotic spindle.

Conclusion:

These findings uncover a novel mechanism controlling the growth of cancer cells at specific modulation frequencies without affecting normal tissues, which may have broad implications in oncology.

Phase II study of intrabuccally-administered amplitude-modulated electromagnetic fields in patients with advanced hepatocellular carcinoma

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Background: Over the past few years we have identified tumor-specific frequencies for several common forms of cancer. The goal of this study was to assess the tolerability and effectiveness of electromagnetic fields amplitude-modulated at tumor-specific frequencies and administered by means of an intrabuccal spoon-shaped probe in patients with advanced hepatocellular carcinoma (HCC). Methods: From October 2005 to July 2007, patients with advanced HCC and Child-Pugh A or B were recruited in a phase II study. Three daily 60 min outpatient treatments were administered until disease progression or death. Imaging studies were performed every eight weeks. The primary efficacy end point was progression-free survival ≥ 6 months. Secondary efficacy end points were progression-free survival and overall survival. Results: A total of 41 patients were enrolled, 17 had Child-Pugh A, 20 Child-Pugh B disease. The median age was 64.0 years. Seventeen patients (34.1%) were progression-free for more than 6 months. Median progression-free and overall survivals were 4.8 months (95% CI 2.3–6.0) and 6.9 months (95 CI 4.8–11.1). As of December 2008, four patients are alive and two patients, who are still undergoing therapy, remain progression-free for 30.4 and 30.7 months, respectively. Four patients had partial response (9.8%) and sixteen had stable disease for at least 12 weeks (39.0%) according to the RECIST criteria resulting in 48.8% disease control. All responses were confirmed by independent review. There were no NCI grade 2, 3 or 4 toxicities. One patient developed grade 1 mucositis and one patient grade 1 fatigue. Conclusions: In patients with advanced HCC and impaired hepatic function, treatment with amplitude-modulated electromagnetic fields is safe, well tolerated, and shows evidence of anti-tumor effects, which are long-lasting in some patients.

No significant financial relationships to disclose.

Impairment of gastric acid secretion and increase of embryonic lethality in Foxq1-deficient mice

The mouse Foxq1 gene, also known as Hfh1, encodes a winged helix/forkhead transcription factor. In adult mice, Foxq1 is highly expressed in kidney and stomach. Here, we report that Foxq1 is expressed during prenatal and postnatal stomach development and the transcripts are restricted to acid secreting parietal cells. Mice homozygous for a deletion of the Foxq1 locus on a 129/Sv x C57BL/6J hybrid genetic background display variable phenotypes consistent with requirement of the gene during embryogenesis. Approximately 50% of Foxq1-/- embryos die in utero. Surviving homozygous mutants are normal and fertile, and have a silky shiny coat. Although the parietal cell development is not affected in the absence of Foxq1, there is a lack of gastric acid secretion in response to various secretagogue stimuli. Ultrastructural analysis suggests that the gastric acid secretion defect in Foxq1-deficient mice might be due to impairment in the fusion of cytoplasmic tubulovesicles to the apical membrane of secretory canaliculi.

A phase I study of therapeutic amplitude-modulated electromagnetic fields (THERABIONIC) in advanced tumors

14072

Background: In vitro studies suggest that low levels of amplitude-modulated electromagnetic fields may modify cell growth. We have identified specific frequencies that may block cancer cell growth. We have developed the THERABIONIC device, a portable and programmable emitter of a 27.12 MHz radiofrequency signal, amplitude-modulated at cancer-specific frequencies ranging from 0.2 to 23,000 Hz with high precision. The device is connected to a spoon-like coupler, which is placed in the patient’s mouth during treatment. The levels of absorbed electromagnetic energy are well below safety limits. Methods: A phase I study consisting of three daily 40 min treatments until disease progression or death. From March 2004 to September 2006, 24 patients with advanced solid tumors were enrolled. The median age was 57.0 ± 12.2 years. 16 patients were female. As of January 2007, 5 patients are still on therapy, 13 patients died of tumor progression, 2 patients are lost to follow-up and one patient withdrew consent. The most common tumor types were breast (7), ovary (5) and pancreas (3). 21 patients had received prior systemic therapy and 16 had documented tumor progression prior to study entry. Results: The median duration of therapy was 15.7 ± 19.9 weeks (range: 0.4–72.0 weeks). There were no NCI grade 2/3/4 toxicities. Three patients experienced grade 1 fatigue during and immediately after treatment. 12 patients reported severe pain prior to study entry. Two of them reported significant pain relief with THERABIONIC treatment. Objective response could be assessed in 13 patients, 6 of whom also had elevated tumor markers. 6 additional patients could only be assessed by tumor markers. Among patients with progressive disease at study entry, one had a partial response for > 14.4 weeks associated with > 50% decrease in CEA, CA 125 and CA 15–3 (previously untreated metastatic breast cancer); one patient had a 50% decrease in CA 19–9 for 12.4 weeks (recurrent and previously systemically-treated pancreatic cancer). Among patients with stable disease at enrollment, four patients maintained stable disease for 17.0, > 19.4, 30.4 and > 63.4 weeks. Conclusions: THERABIONIC is a safe and promising novel treatment modality for advanced cancer.

No significant financial relationships to disclose.

A phase II study of amplitude-modulated electromagnetic fields in the treatment of advanced hepatocellular carcinoma (HCC)

15155

Background: Phase I data show that low levels of electromagnetic fields modulated at specific frequencies administered intrabucally with the THERABIONIC device are a safe and potentially effective treatment for advanced cancer. The device emits a 27.12 MHz radiofrequency signal, amplitude-modulated at tumor-specific frequencies ranging from 0.2 to 23,000 Hz. The device is connected to a spoon- like coupler placed in the patient’s mouth during treatment. Patients with advanced HCC and limited therapeutic options were offered treatment with HCC-specific frequencies. Methods: From October 2005 to October 2006, 38 patients with advanced HCC were recruited in a phase II study. The patients received three daily 40 min treatments until disease progression or death. The median age was 64.0 ± 14.2 years. 32 patients were male and 29 patients had documented progression of disease (POD) by IV contrast imaging prior to study entry. 8 patients had not received prior therapy because of metastases (3), poor medical condition (3), declined chemotherapy (2). Results: As of January 2007, 12 patients are still on therapy, 20 patients died of tumor progression, 2 patients are lost to follow-up and 3 patients withdrew consent. 27 patients are eligible for response. The overall objective response rate as defined by partial response (PR) or stable disease (SD) in patients with prior documented POD was 31.6%: 3 PR and 9 SD. The median survival was 20.7 weeks with a median duration of therapy of 17.5 weeks. 13 patients have received therapy for more than six months. The median duration of response is 12.9 weeks. 12 patients reported pain at study entry: 8 of them (66%) experienced decreased pain during treatment. There were no NCI grade 2/3/4 toxicities. One patient had grade 1 mucositis and grade 1 fatigue. Conclusion: In patients with advanced HCC, THERABIONIC is a safe and effective novel therapeutic option, which has significant anti-tumor effect and provides pain relief in the majority of patients.

[Table: see text]

No significant financial relationships to disclose.

Microarray analysis of formalin-fixed paraffin-embedded specimens shows distinct gene expression patterns in tumors containing the transforming growth factor beta receptor 6A polymorphism (TGFBR1*6A)

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Introduction: A frequent polymorphism of the type I transforming growth factor beta receptor (TGFBR1) is TGFBR1*6A (6A), which has a deletion of 3 CGC triplets coding for alanine within a 9-alanine (9A) repeat of TGFBR1 exon 1. 6A may act as a tumor susceptibility allele through switching TGF-beta growth inhibitory signals into growth stimulatory signals and also appears to be acquired in some cases by primary colon cancers and their liver metastases. Our aim in this study was to compare the gene expression profiles of colorectal tumors bearing the 6A and the more common 9A genotypes to discover pathways that might be differentially induced by the 6A polymorphism. Methods: 28 colorectal tumors with matched synchronous metastases and 23 non-metastatic colorectal tumors were analyzed for TGFBR1 exon 1 genotype by a PCR-based assay. Nine metastatic and 10 non-metastatic tumors were analyzed by gene expression microarrays. Following microdissection of paraffin-embedded specimens, RNA was isolated, amplified, labeled, and hybridized to Affymetrix U133 Plus 2.0 GeneChips. Results: Among the 28 primary metastatic tumors, 19 were 9A (68%), 8 were 9A/6A heterozygotes (29%) and 1 was a 6A homozygote (3%). There was 100% genotype correspondence with the matched metastases. Among the 23 non-metastatic tumors, 18 were 9A (78%), 3 were heterozygotes (13%) and 2 were 6A/6A (9%). Microarray analysis showed 578 differentially expressed genes in the metastatic tumors and 467 in the non-metastatic tumors between the 6A and 9A genotypes (p<0.01). Significant pathway deregulation between 9A and 6A genotypes included estrogen receptor signaling and histidine metabolism in the non-metastatic tumors and B cell receptor, GM-CSF, SAPK/JNK and IL-4 signaling in the metastatic tumors. Conclusion: Microarray analysis shows differentially expressed genes in the 6A genotype compared to 9A, with different deregulated pathways in metastatic and non-metastatic tumors. This alludes to 6A-specific downstream signaling effects, which may contribute to tumor development and progression.

No significant financial relationships to disclose.

Age at first birth and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers

An early age at first full-term birth is associated with a reduction in the subsequent development of breast cancer among women in the general population. A similar effect has not yet been reported among women who carry an inherited BRCA1 or BRCA2 mutation. We conducted a matched case-control study on 1816 pairs of women with a BRCA1 (n = 1405) or BRCA2 (n = 411) mutation in an attempt to elucidate the relationship between age at first full-term pregnancy and the risk of developing breast cancer. Information about the age at first childbirth and other pregnancy-related variables was derived from a questionnaire administered to women during the course of genetic counselling. There was no difference in the mean age at first full-term birth in the cases and controls (24.9 years vs. 24.8 years; P = 0.81, respectively). Compared to women whose first child was born at or before 18 years of age, a later age at first full-term birth did not influence the risk of developing breast cancer (OR = 1.00 per year; 95% CI 0.98-1.03; P-trend = 0.67). Stratification by mutation status did not affect the results. These findings suggest that an early first full-term birth does not confer protection against breast cancer in BRCA mutation carriers. Nonetheless, BRCA mutation carriers opting for a prophylactic oophorectomy as a breast and/or ovarian cancer risk-reducing strategy should complete childbearing prior to age 40 when this prevention modality is most effective.

TGFBR1*6A is not associated with prostate cancer in men of European ancestry

The TGFBR1*6A (*6A) variant in exon 1 of the TGFBR1 gene has been postulated as a putative tumor susceptibility allele in several studies. We have performed a case-control study in 537 men with histologically verified prostate cancer and in 488 unrelated controls to investigate the association of *6A with prostate cancer. Our results revealed that the frequency of the (*)6A allele does not differ in men with prostate cancer compared to healthy controls, even in a subset of age-matched cases and controls. There is no compelling evidence for an association of the *6A variant with prostate cancer.

Isolation and characterization of the human forkhead gene FOXQ1

We have isolated a human genomic and cDNA clone that encodes a protein of 403 amino acids and belongs to the family of the FOX transcription factors (previously called HNF-3/forkhead transcription factors). The 2.7-kb transcript of the human FOXQ1 gene is expressed predominantly in the stomach, trachea, bladder and salivary gland. Additionally, overexpression of human FOXQ1 was shown in colorectal adenocarcinoma and lung carcinoma cell lines. The FOXQ1 gene is located on chromosome 6p23-25. Databank analysis shows 82% homology with the mouse Foxq1 gene (formerly Hfh-1L) and with a revised sequence of the rat FoxQ1 gene (formerly HFH-1). The DNA-binding motif, named HNF-3/forkhead domain, is well conserved, showing 100% identity in human, mouse, and rat. The human protein sequence contains two putative transcriptional activation domains, which share a high amino acid identity with the corresponding mouse and rat domains.

Role of transforming growth factor beta in cancer

Transforming growth factor beta (TGF-beta) is an effective and ubiquitous mediator of cell growth. The significance of this cytokine in cancer susceptibility, cancer development and progression has become apparent over the past few years. TGF-beta plays various roles in the process of malignant progression. It is a potent inhibitor of normal stromal, hematopoietic, and epithelial cell growth. However, at some point during cancer development the majority of transformed cells become either partly or completely resistant to TGF-beta growth inhibition. There is growing evidence that in the later stages of cancer development TGF-beta is actively secreted by tumor cells and not merely acts as a bystander but rather contributes to cell growth, invasion, and metastasis and decreases host-tumor immune responses. Subtle alteration of TGF-beta signaling may also contribute to the development of cancer. These various effects are tissue and tumor dependent. Identifying and understanding TGF-beta signaling pathway abnormalities in various malignancies is a promising avenue of study that may yield new modalities to both prevent and treat cancer. The nature, prevalence, and significance of TGF-beta signaling pathway alterations in various forms of human cancer as well as potential preventive and therapeutic interventions are discussed in this review.

Role of transforming growth factor beta in cancer

Transforming growth factor beta (TGF-beta) is an effective and ubiquitous mediator of cell growth. The significance of this cytokine in cancer susceptibility, cancer development and progression has become apparent over the past few years. TGF-beta plays various roles in the process of malignant progression. It is a potent inhibitor of normal stromal, hematopoietic, and epithelial cell growth. However, at some point during cancer development the majority of transformed cells become either partly or completely resistant to TGF-beta growth inhibition. There is growing evidence that in the later stages of cancer development TGF-beta is actively secreted by tumor cells and not merely acts as a bystander but rather contributes to cell growth, invasion, and metastasis and decreases host-tumor immune responses. Subtle alteration of TGF-beta signaling may also contribute to the development of cancer. These various effects are tissue and tumor dependent. Identifying and understanding TGF-beta signaling pathway abnormalities in various malignancies is a promising avenue of study that may yield new modalities to both prevent and treat cancer. The nature, prevalence, and significance of TGF-beta signaling pathway alterations in various forms of human cancer as well as potential preventive and therapeutic interventions are discussed in this review.

Role of transforming growth factor beta in cancer

Transforming growth factor beta (TGF-beta) is an effective and ubiquitous mediator of cell growth. The significance of this cytokine in cancer susceptibility, cancer development and progression has become apparent over the past few years. TGF-beta plays various roles in the process of malignant progression. It is a potent inhibitor of normal stromal, hematopoietic, and epithelial cell growth. However, at some point during cancer development the majority of transformed cells become either partly or completely resistant to TGF-beta growth inhibition. There is growing evidence that in the later stages of cancer development TGF-beta is actively secreted by tumor cells and not merely acts as a bystander but rather contributes to cell growth, invasion, and metastasis and decreases host-tumor immune responses. Subtle alteration of TGF-beta signaling may also contribute to the development of cancer. These various effects are tissue and tumor dependent. Identifying and understanding TGF-beta signaling pathway abnormalities in various malignancies is a promising avenue of study that may yield new modalities to both prevent and treat cancer. The nature, prevalence, and significance of TGF-beta signaling pathway alterations in various forms of human cancer as well as potential preventive and therapeutic interventions are discussed in this review.

Role of transforming growth factor beta in cancer

Transforming growth factor beta (TGF-beta) is an effective and ubiquitous mediator of cell growth. The significance of this cytokine in cancer susceptibility, cancer development and progression has become apparent over the past few years. TGF-beta plays various roles in the process of malignant progression. It is a potent inhibitor of normal stromal, hematopoietic, and epithelial cell growth. However, at some point during cancer development the majority of transformed cells become either partly or completely resistant to TGF-beta growth inhibition. There is growing evidence that in the later stages of cancer development TGF-beta is actively secreted by tumor cells and not merely acts as a bystander but rather contributes to cell growth, invasion, and metastasis and decreases host-tumor immune responses. Subtle alteration of TGF-beta signaling may also contribute to the development of cancer. These various effects are tissue and tumor dependent. Identifying and understanding TGF-beta signaling pathway abnormalities in various malignancies is a promising avenue of study that may yield new modalities to both prevent and treat cancer. The nature, prevalence, and significance of TGF-beta signaling pathway alterations in various forms of human cancer as well as potential preventive and therapeutic interventions are discussed in this review.

MAD2 haplo-insufficiency causes premature anaphase and chromosome instability in mammalian cells

The mitotic checkpoint protein hsMad2 is required to arrest cells in mitosis when chromosomes are unattached to the mitotic spindle. The presence of a single, lagging chromosome is sufficient to activate the checkpoint, producing a delay at the metaphase-anaphase transition until the last spindle attachment is made. Complete loss of the mitotic checkpoint results in embryonic lethality owing to chromosome mis-segregation in various organisms. Whether partial loss of checkpoint control leads to more subtle rates of chromosome instability compatible with cell viability remains unknown. Here we report that deletion of one MAD2 allele results in a defective mitotic checkpoint in both human cancer cells and murine primary embryonic fibroblasts. Checkpoint-defective cells show premature sister-chromatid separation in the presence of spindle inhibitors and an elevated rate of chromosome mis-segregation events in the absence of these agents. Furthermore, Mad2+/- mice develop lung tumours at high rates after long latencies, implicating defects in the mitotic checkpoint in tumorigenesis.

TbetaR-I(6A) is a candidate tumor susceptibility allele

We have previously described a type I transforming growth factor (TGF)-beta receptor (TbetaR-I) polymorphic allele, TbetaR-I(6A), that has a deletion of three alanines from a nine-alanine stretch. We observed a higher than expected number of TbetaR-I(6A) homozygotes among tumor and nontumor DNA from patients with a diagnosis of cancer. To test the hypothesis that TbetaR-I(6A) homozygosity is associated with cancer, we performed a case-control study in patients with a diagnosis of cancer and matched healthy individuals with no history of cancer and who were identical in their gender and their geographical and ethnic background to determine the relative germ-line frequencies of this allele. We found nine TbetaR-I(6A) homozygotes among 851 patients with cancer. In comparison, there were no TbetaR-I(6A) homozygotes among 735 healthy volunteers (P < 0.01). We also observed an excess of TbetaR-I(6A) heterozygotes in cancer cases compared to controls (14.6% versus 10.6%; P = 0.02, Fisher's exact test). A subset analysis revealed that 4 of 112 patients with colorectal cancer were TbetaR-I(6A) homozygotes (P < 0.01). Using mink lung epithelial cell lines devoid of TbetaR-I, we established stably transfected TbetaR-I and TbetaR-I(6A) cell lines. We found that, compared to TbetaR-I, TbetaR-I(6A) was impaired as a mediator of TGF-beta antiproliferative signals. We conclude that TbetaR-I(6A) acts as a tumor susceptibility allele that may contribute to the development of cancer, especially colon cancer, by means of reduced TGF-beta-mediated growth inhibition.

Molecular analysis of SALL1 mutations in Townes-Brocks syndrome

Townes-Brocks syndrome (TBS) is an autosomal dominantly inherited malformation syndrome characterized by anal, renal, limb, and ear anomalies. Recently, we showed that mutations in the putative zinc finger transcription factor gene SALL1 cause TBS. To determine the spectrum of SALL1 mutations and to investigate the genotype-phenotype correlations in TBS, we examined 23 additional families with TBS or similar phenotypes for SALL1 mutations. In 9 of these families mutations were identified. None of the mutations has previously been described. Two of these mutations are nonsense mutations, one of which occurred in three unrelated families. Five of the mutations are short deletions. All of the mutations are located 5' of the first double zinc finger (DZF) encoding region and are therefore predicted to result in putative prematurely terminated proteins lacking all DZF domains. This suggests that only SALL1 mutations that remove the DZF domains result in TBS. We also present evidence that in rare cases SALL1 mutations can lead to phenotypes similar to Goldenhar syndrome. However, phenotypic differences in TBS do not seem to depend on the site of mutation.

Type I transforming growth factor beta receptor maps to 9q22 and exhibits a polymorphism and a rare variant within a polyalanine tract

In a search for mutations of the type I transforming growth factor beta receptor (TbetaR-I), we mapped the gene to 9q22 and found a common polymorphism [TbetaR-I(6A)] and a rare variant [TbetaR-I(10A)] of TbetaR-I, causing an in-frame deletion of three alanines and an in-frame insertion of one alanine, respectively, in the receptor's extracellular domain. The biological relevance of the polymorphism TbetaR-I(6A) was investigated. When TbetaR-I(6A) was transiently transfected into TbetaR-I-deficient cells, the growth-inhibitory effects of transforming growth factor beta were restored. TbetaR-I(6A) and TbetaR-I(10A) frequency were assessed in 108 tumor samples and 80 nontumor samples from patients with a diagnosis of cancer, as well as in 118 normal blood donors of comparable ethnic composition. The frequency of TbetaR-I(6A) heterozygotes was fairly similar in normal blood donors (8%), in nontumor DNA of patients with a diagnosis of cancer (10%), and in tumor samples (14%). However, the frequency of TbetaR-I(6A) homozygotes among nontumor (4%) and tumor (8%) samples obtained from patients with a diagnosis of cancer was higher than that predicted by the Hardy-Weinberg law. The clinical and biological significance of TbetaR-I(6A) homozygosity needs to be further investigated.

Bright light and LEET effects on circadian rhythms, sleep and cognitive performance

Shift work and jet lag can disrupt cicadian rhythms, with detrimetnal effects on alertness, performance and sleep. This study examined the effects of two interventions to adapt circadian rhythms, sleep and performance to a 10-h phase delay of the work-rest cycle. Bright light was administered from 2200 to 0200 each night to promote phase delay of circadian rhythms. Low energy emission therapy (LEET) was administered for 20 min prior to daytime sleep periods to promote sleep. Twelve subjects received bright light, 12 subjects received LEET, 11 received both interventions and 10 control subjects received only placebo treatments. Bright light accelerated phase delay of the circadian melatonin rhythms after the work-rest schedule shift. Further, subjects who received bright light had greater total sleep time (TST) and improved sleep continuity. LEET treatment produced a trend (p = 0.16) for increased TST, but LEET did not affect the melatonin circadian rhythm. After the schedule shift, cognitive performance measures showed few significant differences. Some minor improvements in cognitive performance were producced by light treatments but not by LEET.

Effects of low energy emission therapy in chronic psychophysiological insomnia

The treatment of chronic psychophysiological insomnia presents a challenge that has not been met using currently available pharmacotherapy. Low energy emission therapy (LEET) has been developed as a potential alternative therapy for this disorder. LEET consists of amplitude-modulated electromagnetic fields delivered intrabuccally by means of an electrically conducting mouthpiece in direct contact with the oral mucosa. The effect of LEET on chronic psychophysiological insomnia was assessed with polysomnography (PSG) and sleep rating forms on a total of 106 patients at two different centers. Active or inactive LEET was administered for 20 minutes in late afternoon three times a week for a total of 12 treatments. Primary efficacy endpoints evaluating the results were changes from baseline in PSG-assessed total sleep time (TST) and sleep latency (SL). Secondary endpoints were changes in sleep efficiency (SE), sleep stages, and reports by the subjects of SL and TST. There was a significant increase in TST as assessed by PSG between baseline and post-treatment values for the active treatment group (76.0 +/- 11.1 minutes, p = 0.0001). The increase for the inactive treatment group was not statistically significant. The TST improvement was significantly greater for the active group when compared to the inactive group (adjusted for baseline TST; p = 0.020. R1 = 0.20). There was a significant decrease in SL as assessed by PSG between baseline and post-treatment values for the active treatment group (-21.6 +/- 5.9 minutes, p = 0.0006), whereas the decrease noted for the inactive treatment group was not statistically significant. The difference in SL decrease between the two treatment groups was marginally significant (adjusted for baseline SL and center, p = 0.068, R2 = 0.60). The number of sleep cycles per night increased by 30% after active treatment (p = 0.0001) but was unchanged following inactive treatment. Subjects did not experience rebound insomnia, and there were no significant side effects. The data presented in this report indicate that LEET administered for 20 minutes three times a week increased TST and reduced SL in chronic psychophysiological insomnia. LEET is safe and well tolerated and it effectively improved the sleep of chronic insomniacs given 12 treatments over a 4-week period by increasing the number of sleep cycles without altering the percentage of the various sleep stages during the night. The therapeutic action of LEET differs from that of currently available drug therapies in that the sleep pattern noted in insomniacs following LEET treatment more closely resembles nocturnal physiological sleep. This novel treatment may offer an attractive alternative therapy for chronic insomnia.

Electroencephalographic changes following low energy emission therapy

Low energy emission therapy (LEET) is a novel approach to delivering low levels of amplitude-modulated electromagnetic fields to the human brain. The sleep electroencephalogram (EEG) effects of a 15-min LEET treatment were investigated in a double-find cross-over study to assess sleep induction. Fifty-two healthy volunteers were exposed to both active and inactive LEET treatment sessions, with a minimum interval of 1 week between the two sessions. Baseline EEGs were obtained, and 15-min posttreatment EEGs were recorded and analyzed according to the Loomis classification. A significant increase in the duration of stage B1 sleep (0.58 +/- 2.42 min [mean +/- SD], p = 0.046), decreased latency to the first 10 sec epoch of sleep (-1.23 +/- 5.32 min, p = 0.051) and decreased latency to sleep stage B2 (-1.21 +/- 5.25 min, p = 0.052) were observed after active treatment. Additionally, establishment of slow waves with progression from stages B to C was significantly more pronounced after active LEET treatment (p = 0.040). A combined analysis of these results with those of an identical study performed in Denver showed that LEET had a significant effect on afternoon sleep induction and maintenance with shorter sleep latencies (decreased latency to the first 10 sec epoch of sleep; -1.00 +/- 5.51 min, p = 0.033; decreased latency to sleep stage B2; -1.49 +/- 5.40 min, p = 0.003), an increased duration of stage B2 (0.67 +/- 2.50 min, p = 0.003), an increase in the total duration of sleep (0.69 +/- 4.21 min, p = 0.049), and a more prominent establishment of slow waves with progression to a deeper sleep stage (p = 0.006). It is concluded that the intermittent 42.7 HZ amplitude modulation of 27.12-MHz electromagnetic fields results in EEG changes consistent with shorter sleep latencies, longer sleep duration, and deeper sleep in healthy subjects.

Platelets and plasminogen activation

Platelets serve as a site for assembly of the proteins of the plasminogen activator system. Once bound to the platelet surface, tissue-type plasminogen activator manifests enhanced catalytic activity. Plasmin, once formed, also binds to the platelets surface and, at low concentrations, renders the platelet dysfunctional by cleaving glycoprotein IIIa selectively in the presence of bound fibrinogen. At higher concentrations (approximately 1 caseinolytic unit/ml), plasmin activates the platelet directly. Activated platelets also bind plasminogen and tissue-type plasminogen activator, and manifest enhanced catalytic efficiency of plasminogen activation. These observations suggest that plasminogen activation by tissue-type plasminogen activator is an autocatalytic process on the platelet surface, and that unique reciprocating mechanisms govern the interaction between platelets and the components of the plasminogen activator system.

Structural changes in platelet glycoprotein IIb/IIIa by plasmin: determinants and functional consequences

Plasmin exposure modulates platelet aggregation responses, but a direct effect of plasmin on the platelet fibrinogen receptor, glycoprotein IIb/IIIa (GPIIb/IIIa), has never been conclusively shown in a plasma milieu. To examine this issue, we incubated platelets in platelet-rich plasma with plasmin and measured the effect of this treatment on platelet aggregation, fibrinogen binding, and the structural integrity of GPIIb/IIIa. Plasmin treatment reduced maximal reversible fibrinogen binding in a dose-dependent fashion, and this reduction in binding was accompanied by a correlative reduction in the maximal rate of aggregation. Immunoblots performed with polyclonal antibodies against GPIIb/IIIa showed that GPIIIa had been cleaved by plasmin, but this cleavage was detected only after subsequent degradation of the solubilized GPIIb/IIIa with Staphylococcus aureus V8 (Glu-C) endoprotease. Peptide sequence analysis showed that cleavage occurred at the lys444-pro445 bond in the first cysteine-rich repeat domain of GPIIIa a unique proteolytic event observed only in the presence of plasma fibrinogen. These observations suggest that plasmin modifies GPIIIa by a unique proteolytic event in plasma that is dependent on fibrinogen binding and, consequently, is accompanied by significant reductions in fibrinogen binding and aggregation response.

Sleep inducing effect of low energy emission therapy

The sleep inducing effect of a 15 min treatment with either an active or an inactive Low Energy Emission Therapy (LEET) device emitting amplitude-modulated electromagnetic (EM) fields was investigated in a double-blind cross-over study performed on 52 healthy subjects. All subjects were exposed to both active and inactive LEET treatment sessions, with an interval of at least 1 week between the two sessions. LEET consists of 27.12 MHz amplitude-modulated (sine wave) EM fields emitted intrabuccally by means of an electrically conducting mouthpiece in direct contact with the oral mucosa. The estimated local peak SAR is less than 10 W/kg in the oral mucosa and 0.1 to 100 mW/kg in brain tissue. No appreciable sensation is experienced during treatment, and subjects are therefore unable to tell whether they are receiving an active or an inactive treatment. In this study the active treatment consisted of EM fields intermittently amplitude-modulated (sine wave) at 42.7 Hz for 3 s followed by a pause of 1 s during which no EM fields were emitted. During the inactive treatment no EM fields were emitted. Baseline EEGs were obtained and 15 min post-treatment EEGs were recorded and analyzed according to the Loomis classification. A significant decrease (paired t test) in sleep latency to stage B2 (-1.78 +/- 5.57 min, P = 0.013), and an increase in the total duration of stage B2 (1.15 +/- 2.47 min, P = 0.0008) were observed on active treatment as compared with inactive treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

The platelet function defect of cardiopulmonary bypass

The use of cardiopulmonary bypass (CPB) during cardiac surgery is associated with a hemostatic defect, the hallmark of which is a markedly prolonged bleeding time. However, the nature of the putative platelet function defect is controversial. In this study, blood was analyzed at 10 time points before, during, and after CPB. We used a whole-blood flow cytometric assay to study platelet surface glycoproteins in (1) peripheral blood, (2) peripheral blood activated in vitro by either phorbol myristate acetate, the thromboxane (TX)A2 analog U46619, or a combination of adenosine diphosphate and epinephrine, and (3) the blood emerging from a bleeding-time wound (shed blood). Activation-dependent changes were detected by monoclonal antibodies directed against the glycoprotein (GP)Ib-IX and GPIIb-IIIa complexes and P-selectin. In addition, we measured plasma glycocalicin (a proteolytic fragment of GPIb) and shed-blood TXB2 (a stable breakdown product of TXA2). In shed blood emerging from a bleeding-time wound, the usual time-dependent increase in platelet surface P-selectin was absent during CPB, but returned to normal within 2 hours. This abnormality paralleled both the CPB-induced prolongation of the bleeding time and a CPB-induced marked reduction in shed-blood TXB2 generation. In contrast, there was no loss of platelet reactivity to in vitro agonists during or after CPB. In peripheral blood, platelet surface P-selectin was negligible at every time point, demonstrating that CPB resulted in a minimal number of circulating degranulated platelets. CPB did not change the platelet surface expression of GPIb in peripheral blood, as determined by the platelet binding of a panel of monoclonal antibodies, ristocetin-induced binding of von Willebrand factor, and a lack of increase in plasma glycocalicin. CPB did not change the platelet surface expression of the GPIIb-IIIa complex in peripheral blood, as determined by the platelet binding of fibrinogen and a panel of monoclonal antibodies. In summary, CPB resulted in (1) markedly deficient platelet reactivity in response to an in vivo wound, (2) normal platelet reactivity in vitro, (3) no loss of the platelet surface GPIb-IX and GPIIb-IIIa complexes, and (4) a minimal number of circulating degranulated platelets. These data suggest that the "platelet function defect" of CPB is not a defect intrinsic to the platelet, but is an extrinsic defect such as an in vivo lack of availability of platelet agonists. The near universal use of heparin during CPB is likely to contribute substantially to this defect via its inhibition of thrombin, the preeminent platelet activator.

Binding of antithrombin to immobilized heparin under varying flow conditions

Rheologic factors are likely to influence the balance between thrombotic and antithrombotic forces at the level of the vascular wall. In this study, the effects of flow-velocity/wall shear stress on the interaction of antithrombin (AT) with surface-immobilized heparin were investigated. The binding of AT to low-affinity and high-affinity heparin could be discriminated by measurements at physiological of elevated ionic strength. Under low shear stress conditions, substantial binding of AT to both high- and low-affinity heparin was observed, in relative quantities largely reflecting the proportion of these polysaccharide populations on the surface. With increasing shear stress, the binding to high-affinity sites was relatively constant, while total low-affinity binding decreased. Furthermore, under the highest shear stress (greater than 1,000 N/m2), the binding of AT to low-affinity heparin completely disappeared while binding to the high-affinity fraction persisted. These results were related to values obtained in a mathematical model, describing the theoretical maximum transport of AT from the liquid phase to the surface under the conditions used in the experimental system.

Thrombin-inhibitory capacity of the injured vessel wall

The present study examined the appearance of thrombin activity in vitro after single and repeated in vivo balloon injury of the rabbit aorta. The in vitro ability of the injured vessel wall to bind and subsequently inhibit thrombin in the presence of defibrinogenated plasma was also assessed. Thrombin activity was assayed by measuring the levels of fibrinopeptide A generated in the presence of fibrinogen. These findings were correlated with the changes observed in light and electron microscopy. Thrombin activity on the vessel wall was increased five minutes and three hours after the initial and the repeated injury, and returned to control values one week after the initial injury. When the inhibition of thrombin was assayed in the presence of defibrinogenated plasma, a diminished inhibition capacity was observed after the repeated injury, which correlated with deposition of fibrin and an enhanced inflammatory reaction as measured by the density of granulocytes covering the injured neointima. Decreased thrombin inhibitory capacity of the injured neointima appears to be linked with its increased thrombogenicity.

Heparin cofactor II significance for the inhibition of thrombin at the injured vessel wall

The thrombin inhibitory role of antithrombin III (ATIII) and heparin cofactor II (HCII) was studied in vitro using intact and injured rabbit aortae. When intact vessels were loaded with thrombin and then exposed to either heat defibrinogenated human plasma (HDHP) or ATIII the same degree of thrombin inhibition was achieved demonstrating that ATIII was the only plasma component involved in thrombin inhibition on the intact vessel wall. When the media of the vessel wall was loaded with thrombin and then exposed to ATIII or HCII a significantly higher thrombin activity remained on the surface than when it was exposed to defibrinogenated plasma. A mixture of ATIII and HCII resulted in a greater inhibition of thrombin than ATIII or HCII alone. It is concluded that, contrary to what happens on the endothelium, HCII and ATIII inhibit additively thrombin on the injured vessel wall. HCII thus plays an essential role for the inhibition of thrombin at the injured vessel wall. It is also concluded that an additional plasma component participates in thrombin inhibition on the media but its contribution is negligible as compared with ATIII or HCII.

The use of a commercial ELISA for assay of thrombin-antithrombin complexes in purified systems

Inhibition of thrombin by antithrombin III (AT) results in the formation of stable thrombin-AT complexes (TAT). An enzyme-linked immunosorbent assay (ELISA) following the sandwich principle is available for the determination of TAT complexes in human plasma, however, this ELISA method could not be used in purified systems containing thrombin and AT. It has therefore been modified for use in purified systems and an excellent correlation was found between the disappearance of thrombin and AT and the recovery of TAT complexes. Addition of thrombin inhibitor hirudin and heparin inhibitor polybrene into the reacting thrombin-AT mixture did not interfere with the assay of TAT. It was found that the use of siliconised tubes was necessary for the conservation of the TAT complexes.

Influence of high and low wall shear rates on the inhibition of factor Xa and thrombin at surfaces coated with immobilized heparin

The thromboresistant function of a surface with end-point attached heparin is based upon interaction among the immobilized heparin, antithrombin, and at least factor Xa or thrombin. Heparinized arteriovenous shunts were implanted in dogs. By compressing a segment of the shunt, high and low wall shear rate regions were obtained in each shunt. After removal, the tubings were tested for their factor Xa and thrombin inhibitory capacity. It was found that on a molar basis, the factor Xa and thrombin inhibitory capacity were similar in low wall shear rate segments. In high wall shear rate segments, the thrombin inhibitory capacity was decreased, thus indicating that the AT-mediated inhibition of the serine protease is dependent on the wall shear rate.

Antithrombin III binding to surface immobilized heparin and its relation to F Xa inhibition

The mode of F Xa inhibition was investigated on a thromboresistant surface with end-point attached partially depolymerized heparin of an approximate molecular weight of 8000. Affinity chromatography revealed that one fourth of the heparin used in surface coating had high affinity for antithrombin III (AT). The heparin surface adsorbed AT from both human plasma and solutions of purified AT. By increasing the ionic strength in the AT solution the existence of high and low affinity sites could be shown. The uptake of AT was measured and the density of available high and low affinity sites was found to be in the range of 5 and 11 picomoles/cm2, respectively. Thus the estimated density of biologically active high and low affinity heparin respectively would be 40 and 90 ng/cm2. The heparin coating did not take up or exert F Xa inhibition by itself. With AT adsorbed on both high and low affinity heparin the surface had the capacity to inhibit several consecutive aliquots of F Xa exposed to the surface. When mainly high affinity sites were saturated with AT the inhibition capacity was considerably lower. It was demonstrated that the density of AT on both high and low affinity heparin determines the F Xa inhibition capacity whereas the amount of AT on high affinity sites limits the rate of the reaction. This implies that during the inhibition of F Xa there is a continuous surface-diffusion of AT from sites of a lower class to the high affinity sites where the F Xa/AT complex is formed and leaves the surface. The ability of the immobilized heparin to catalyze inhibition of F Xa is likely to be an important component for the thromboresistant properties of a heparin coating with non-compromised AT binding sequences.

Thrombin inactivation on surfaces with covalently bonded heparin

About 8000 Daltons porcine mucosa heparin fragments were covalently bonded by end-point attachment to polyethylene. The interaction between the immobilized heparin, added thrombin, and antithrombin III [AT] was investigated. The heparin surface was adsorbed with either albumin, AT dissolved in albumin or Tyrode, or platelet free plasma. Irrespective of the pre-treatment procedure, exposure of the surface to thrombin resulted in the same substantial decrease of thrombin in solution and the same degree of surface-confined thrombin activity. It was concluded that the heparin surface has a large capacity to bind thrombin and that the thrombin inhibitory capacity of high affinity heparin fragments is limited. On exposure of the thrombin-loaded surfaces to defibrinogenated plasma or AT, the surface-confined thrombin was inhibited within 30 seconds. Successive dilutions of plasma or AT decreased the inhibition rate but not the inhibition capacity. It is concluded that inhibition of thrombin adsorbed on the heparin surface occurs as follows: Added AT adheres to high affinity heparin fragments on the surface whereupon adsorbed thrombin migrates in the hydrophilic heparin coating towards the reaction site of AT and becomes inhibited. The inactivated thrombin-AT complex leaves then the surface, thus enabling the process to be repeated.