Constraints on the fundamental string coupling from B-mode experiments.

We study signatures of cosmic superstring networks containing strings of multiple tensions and Y junctions, on the cosmic microwave background (CMB) temperature and polarization spectra. Focusing on the crucial role of the string coupling constant g(s), we show that the number density and energy density of the scaling network are dominated by different types of string in the g(s) ~ 1 and g(s) ≪ 1 limits. This can lead to an observable shift in the position of the B-mode peak--a distinct signal leading to a direct constraint on g(s). We forecast the joint bounds on g(s) and the fundamental string tension µ(F) from upcoming and future CMB polarization experiments, as well as the signal to noise in detecting the difference between B-mode signals in the limiting cases of large and small g(s). We show that such a detectable shift is within reach of planned experiments.

Surgical wound healing in radio-tagged adult Pacific lamprey Entosphenus tridentatus held on different substrata.

Radio-tagged adult Pacific lamprey Entosphenus tridentatus held in a raceway with Plexiglas-lined walls and bottom healed more slowly and retained sutures longer than fish held in an all-concrete raceway or one with Plexiglas walls and a cobble-lined bottom. On all substrata, healing depended on when sutures were lost, and fish that lost their sutures in <14 days post-surgery healed faster than those that kept sutures longer. Long-term suture retention led to tissue trauma, infection and poor survival.

Human tumor necrosis factor receptor (p55) and interleukin 10 gene transfer in the mouse reduces mortality to lethal endotoxemia and also attenuates local inflammatory responses.

Anticytokine therapies have been promulgated in gram-negative sepsis as a means of preventing or neutralizing excessive production of proinflammatory cytokines. However, systemic administration of cytokine inhibitors is an inefficient means of targeting excessive production in individual tissue compartments. In the present study, human gene transfer was used to deliver to organs of the reticuloendothelial system antagonists that either inhibit tumor necrosis factor-alpha (TNF-alpha) synthesis or block its interactions with cellular receptors. Mice were treated intraperitoneally with cationic liposomes containing 200 micrograms of either a pCMV (cytomegalovirus)/p55 expression plasmid that contains the extracellular domain and transmembrane region of the human p55 TNF receptor, or a pcD-SR-alpha/hIL-10 expression plasmid containing the DNA for human interleukin 10. 48 h later, mice were challenged with lipopolysaccharide (LPS) and D-galactosamine. Pretreatment of mice with p55 or IL-10 cDNA-liposome complexes improved survival (p < 0.01) to LPS-D-galactosamine. In additional studies, intratracheal administration of IL-10 DNA-liposome complexes 48 h before an intratracheal LPS challenge reduced pulmonary TNF-alpha levels by 62% and decreased neutrophil infiltration in the lung by 55% as measured by myeloperoxidase activity (both p < 0.05). Gene transfer with cytokine inhibitors is a promising option for the treatment of both the systemic and local sequelae of septic shock.

A human tumor necrosis factor p75 receptor agonist stimulates in vitro T cell proliferation but does not produce inflammation or shock in the baboon.

Tumor necrosis factor (TNF) is a potentially useful adjunct to anticancer therapies. However, the clinical utility of TNF has been limited by generalized toxicity and hypotension. Recently, studies have begun to dissect the individual proinflammatory and immunologic responses that result from TNF binding to its two cellular receptors, p55 and p75, in an attempt to develop TNF receptor agonists with reduced systemic toxicity. To evaluate a p75 receptor selective TNF mutant (p75TNF), TNF and p75TNF were administered to healthy anesthetized baboons. Intravenous infusion of the p75TNF produced none of the hemodynamic changes seen after the infusion of TNF. Infusion of p75TNF also failed to induce the plasma appearance of interleukins 6 and 8. However, p75TNF enhanced in vitro baboon thymocyte proliferation to concanavalin A, and infusion of p75TNF resulted in increased soluble p55 and p75 receptor plasma concentrations. Local skin necrosis and tissue neutrophil infiltration were seen after subcutaneous injections of TNF and p55TNF. Subcutaneous injection of p75TNF did not result in skin necrosis but did result in a modest dermal infiltration of lymphocytes and macrophages. The findings suggest that p75TNF may stimulate T cell proliferation without the systemic and local toxicity seen with TNF.

Salt transport organelle in Artemia salenis (brine shrimp).

The branchiae of Artemia adapted to triple-strength sea water (105 per mil salinity) were studied with the electron microscope. The epithelial lining of the metepipodite segment possesses organelles composed of stacks of disc-shaped mitochondria interlaced with flattened extensions of a canalicular system that in turn communicates with the plasma-bound surface of the cells. The distance between the canalicular and mitochondrial membranes is small and quite constant. The marked similarity to "mitochondrial pumps" in the anal papillae of tosquito larvae suggests that the organelle is concerned with salt transport.

Enhanced hepatic amino acid transport in tumor-bearing rats is partially blocked by antibody to tumor necrosis factor.

The liver of the host with cancer exhibits an enhanced requirement for amino acids to support tumor-induced increases in hepatic protein synthesis and gluconeogenesis. To address the mechanism by which the liver ensures adequate delivery of these substrates for intracellular utilization during cancer, we studied the activities of several amino acid transporters in hepatic plasma membrane vesicles prepared from rats implanted with a rapidly growing s.c. fibrosarcoma. The presence of the tumor resulted in a generalized stimulation of concentrative (Na(+)-dependent) glucogenic (small neutral) amino acid uptake via System A (3.4-fold), System N (2.3-fold), and System ASC (1.7-fold), as well as in the facilitative (Na(+)-independent) uptake of arginine via System y+ (1.7-fold). Kinetic analysis revealed that the tumor-induced enhancement of transport activity was due to increases in the maximum transport velocity (Vmax), whereas transporter substrate affinities (Km) did not change significantly. Administration of antibody to tumor necrosis factor-alpha to tumor-bearing rats attenuated the increase in hepatic amino acid transport activity by 60-100%. Treatment of nontumor-bearing control rats with tumor necrosis factor-alpha mAb did not alter basal transport activity. The results from these studies suggest that the tumor elicits a generalized increase in hepatic plasma membrane amino acid transport activity via a pathway that involves the cytokine tumor necrosis factor.

Parenteral nutrition techniques in cancer patients.

If a patient is expected to respond optimally to one or more forms of oncologic therapy, he should simultaneously be in the best possible nutritional and metabolic condition. When the alimentary tract cannot be used effectively for feeding cancer patients, parenteral nutrition can be lifesaving. Moreover, patients who are poor candidates or noncandidates for any antineoplastic therapy because of their debility or cachexia can be converted to reasonable candidates following a course of i.v. hyperalimentation. This i.v. hyperalimentation can significantly reduce the morbidity and mortality of cancer patients without stimulating tumor growth when applied conscientiously according to the established principles and techniques and when integrated with specific tumor therapy. With the use of ambulatory or home hyperalimentation techniques, normal nutritional status can be restored or maintained during prolonged periods of antineoplastic therapy on a practical and relatively economical outpatient basis. It is anticipated that specific nutrient substrate formulas and parenteral therapy techniques will be developed to maintain optimal host nutrition while adversely affecting the neoplasm.

Interaction between cytosolic monoamine oxidase and spin-labeled amphetamine and its modification by clorgyline and pargyline.

Interactions between a monoamine oxidase (monoamine: oxygen oxidoreductase deaminating, EC 1.4.3.4) obtained from rat liver cytosol by high speed centrifugation and a biologically active, spin labeled analog of amphetamine have been analyzed. The acetylenic monoamine oxidase inhibitors, pargyline and clorgyline, have been used to modulate the binding of spin labeled amphetamine. Broadening of electron spin resonance lines induced by immobilization of the probe on binding has been used to determine the concentration of bound probe. Pargyline was found to inhibit binding of spin labeled amphetamine by cytosolic monoamine oxidase. Bound spin labeled amphetamine was also displaceable by pargyline. In contrast, clorgyline enhanced the binding of spin labeled amphetamine to the cytosolic monoamine oxidase preparation. Inhibition or enhancement of amphetamine binding was very rapid and occurred during the reversible stage of interaction between the enzyme and the acetylenic compounds.

Conservative treatment of rectal adenocarcinoma with endocavitary irradiation or wide local excision and postoperative irradiation.

PURPOSE: To evaluate the role of endocavitary irradiation and wide local excision followed by irradiation in the treatment of early-stage rectal adenocarcinoma. MATERIALS AND METHODS: Sixty-five patients with early-stage adenocarcinoma of the rectum were treated with endocavitary irradiation (n = 20) or wide local excision followed by external-beam irradiation (n = 45) between 1974 and 1994 at the University of Florida. All patients were monitored for a minimum of 2 years or until death. RESULTS: The rates of local-regional control at 5 years were 80% after endocavitary irradiation and 86% after wide local excision and radiotherapy. The ultimate 5-year local-regional control rates were 85% and 92%, respectively. Multivariate analysis of local-regional control with sphincter preservation showed that tumor configuration (exophytic v ulcerative) significantly influenced this end point; local-regional control was decreased in patients with ulcerated cancers. Five-year cause-specific survival rates were 84% after endocavitary irradiation and 88% after wide local excision and radiotherapy. Multivariate analysis revealed that tumor configuration significantly influenced cause-specific survival; patients with ulcerated tumors had a worse prognosis. CONCLUSION: Endocavitary irradiation is a highly effective treatment for properly selected patients with early-stage rectal adenocarcinoma. Patients with less favorable lesions that appear to be limited to the muscularis propria have a high chance of cure with sphincter preservation after wide local excision and external-beam irradiation.

Altered steady-state mRNA levels of basement membrane proteins in diabetic mouse kidneys and thromboxane synthase inhibition.

We examined steady-state levels of mRNA encoding type IV collagen, B1 chain of laminin, and the basement membrane heparan sulfate proteoglycan in the kidney cortex of a mouse model (KKAy) of non-insulin-dependent diabetes. mRNAs encoding laminin B1 and the proteoglycan were unchanged in kidneys taken from diabetic mice with demonstrable basement membrane thickening. mRNA levels for type IV collagen, in contrast, were significantly elevated (2-fold) in diabetic mice concurrent with but not preceding morphologically thickened basement membranes. There was a negative correlation between a ratio of proteoglycan/type IV collagen and levels of albuminuria in the diabetic mice. No correlation was noted with laminin. We also examined the effects of inhibiting the synthesis of thromboxane, a potent vasoconstrictor, on the steady-state levels of type IV collagen in the diabetic mice. Inhibition of thromboxane stopped the progression of albuminuria and prevented an increase in type IV collagen mRNA levels. We conclude that basement membrane thickening in diabetes, a hallmark of diabetic nephropathy, is partly a consequence of an unbalanced increase in the production of type IV collagen. The relative decrease in proteoglycan production may contribute to chronic albuminuria.

An in vitro and in vivo investigation of the phototoxic effect and its amelioration with radioprotective compounds.

Electron spin resonance spectroscopy has been used to demonstrate that the phototoxic antimalarial drug, 6,8-dichloro-2-phenyl-a-2-piperidnylquinolinemethanol (WR 7930), when irradiated with long-wave ultraviolet (UV) light (lambda greater than 320 nm) while held in a glassy matrix at 73 degrees K, enters a triplet state and releases hydrogen atoms in its environment. The steady-state concentration of triplet WR 7930 molecules and of hydrogen atoms is reduced 2 to 3 times when mercaptoethylamine (MEA) is also present in the UV-irradiated glass. Organosulfur radicals form on MEA while hydrogen atoms and triplet-state molecules are reduced in number. Hydrogen atoms and triplet WR 7930 molecules are considered as mediators of the phototoxicity of the antimalarial drug. Thus, hydrogen atom scavanging and chemical quenching of the triplet state are possible mechanisms by which protection against phototoxic effects could be gained. Protection is demonstrated in mice receiving 20 mg per kg WR 7930 intraperitoneally and exposed to long-wave UV for 20 hr when the radioprotective aminothiol-forming compound, 2-(3-aminopropylamino) ethyl dihydrogen phosphorothioate (WR 2721), is administered at 400 mg per kg immediately before irradiation. When no protective drug is administered concurrently, WR 7930 administration results in intense erythema, edema, and eventual necrosis of ear tissues.

Total parenteral nutrition in mice bearing a metastatic carcinoma: tumor growth, metastasis and immunologic parameters.

The role of dietary manipulation of tumor growth, metastasis and immunologic parameters was studied in mice bearing Lewis lung carcinoma. Fourteen days following subcutaneous tumor implant, groups with tumor and their non-tumor bearing counterparts were assigned to one of the following feeding protocols: total parenteral nutrition (TPN), per oral (PO) intake of the parenteral diet, an oral casein diet (CAS), or electrolyte infusion plus the casein diet (ELECT). Intakes of energy and nitrogen were similar among all groups. Mice were killed 12 days later and peritoneal macrophages were tested for phagocytic activity. Tumor growth and metastasis were decreased from both infusion regimens with minimal loss of body weight as compared with casein fed mice. PO mice also showed lower tumor weight but metastasis was as great as in the casein group. Non-tumor-bearing infused mice showed depressed thymic weight, but thymic weight was not further reduced in tumor-bearing infused mice. PO feeding afforded no such protection in the presence of the carcinoma. Splenomegaly was observed in tumor-bearing mice on all regimens, but mice maintained on the parenteral diet demonstrated the largest proportion of macrophages containing nuclear debris. Analysis of free macrophages indicated no effect of diet regimen on non-immune phagocytic activity in both tumor-free and tumor-bearing mice. Possible alteration of splenic macrophage intracellular digestive capacity or phagocytic activity was suggested as a result of TPN.

Liposome spin immunoassay: a new sensitive method for detecting lipid substances in aqueous media.

A new sensitive immunoassay procedure is described for quantitative detection of glycolipids and other lipids in aqueous media. As with other immunoassays specific antiserum is first reacted with the free lipid hapten. The amount of antibody activity remaining is measured by assaying the release, in the presence of complement, of spin label marker from liposomes containing the same lipid hapten. Using this method, 2.6 pmol of aqueous Forssman hapten was detected, and the sensitivity could be increased further.

Isolated local-regional recurrence following mastectomy for adenocarcinoma of the breast treated with radiation therapy alone or combined with surgery and/or chemotherapy.

The results of radiation therapy alone or combined with surgery and/or chemotherapy are reported for 47 patients who presented with local and/or regional recurrence without evidence of distant metastases following initial management of adenocarcinoma of the breast with radical or modified radical mastectomy (43) or simple mastectomy (4). Patients were treated between October 1964 and March 1983 at the University of Florida; all have a 2-year minimum follow-up and 42/47 (89%) have had follow-up for greater than or equal to 5 years. The overall actuarial local-regional control rates were 80% at 2 years, 68% at 5 years, and 61% at 10 years. The 5-year actuarial local-regional control rates by site and extent of disease were as follows: single chest wall nodule, 92%; multiple chest wall nodules, 49%; regional lymph nodes, 66%; and multiple sites, 64%. The 5- and 10-year actuarial determinate disease-free survival rates for all patients were 41 and 17%, respectively. The 5- and 10-year actuarial survival rates for all patients were 50 and 34%, respectively.

Interleukin-1 and interleukin-1 antagonism in sepsis, systemic inflammatory response syndrome, and septic shock.

Interleukin-1 (IL-1) is one of several proinflammatory cytokines produced during infection, sepsis, and the systemic inflammatory response syndrome (SIRS) that serves to initiate the host inflammatory response and to integrate nonspecific immunity. Many of IL-1's biologic effects are beneficial to the host in times of stress, but when produced for extended periods of time or in excessive quantities, IL-1 contributes to morbidity and mortality. In fact, excessive IL-1 production has been directly linked to the development of hypotension, shock, multi-organ system failure, hematologic dyscrasia, and death in patients and animals with sepsis, SIRS, and septic shock. Recent research interest has focused on IL-1 inhibition to improve outcome in sepsis and septic shock. This article will review the role for IL-1 in sepsis and septic shock, and the function and status of the IL-1 receptors and IL-1 receptor antagonist in modulating IL-1 actions. The results of investigations of IL-1 inhibition in animal models and in human subjects with sepsis and septic shock will also be reviewed.

Application of gene therapy to acute inflammatory diseases.

The application of gene therapy to acute inflammation has not received as much research attention as has the treatment of genetically-based diseases, cancer, and viral infections. However, gene therapy as a drug delivery system offers several theoretical and practical advantages over current protein delivery systems. These include the ability to target therapies to individual tissues or cell types, to locally produce proteins that can act intracellularly or in an autocrine, juxtacrine, or paracrine fashion, and to sustain new protein synthesis for periods up to several weeks after a single administration. Although retrovirus, herpes simplex, and adeno-associated virus have been proposed for gene therapy in cancer and in genetic diseases, nonviral and adenovirus approaches appear most applicable as drug delivery systems due to their rapid onset and short duration of transgene expression. The relative modest transduction efficiencies obtained at present with nonviral approaches, and the inherent inflammatory properties of first-generation adenovirus constructs, however, have limited their usefulness to date. The present review discusses the theoretical and practical benefits of specific gene therapy approaches for the treatment of acute inflammatory diseases, as well as our experiences with liposome:plasmid DNA and adenovirus-based approaches. Although a number of technical and theoretical hurdles remain before it can be evaluated in humans with acute inflammation, gene therapy offers a novel approach for the treatment of acute inflammation, and will likely enter the armamentarium of critical care physicians in the near future.

A matrix metalloproteinase inhibitor prevents processing of tumor necrosis factor alpha (TNF alpha) and abrogates endotoxin-induced lethality.

Excessive tumor necrosis factor alpha (TNF alpha) production in response to Gram-negative bacteremia or endotoxemia can often lead to hypotension, shock, and increased mortality. Current approaches used to block the deleterious effects of exaggerated TNF alpha production rely on monoclonal antibodies or immunoadhesins that bind TNF alpha and thus prevent the interaction with its cellular receptors. This report examines whether a previously described inhibitor of matrix metalloproteinases, GM-6001, can inhibit TNF alpha processing and release and attenuate endotoxin-induced mortality. In human peripheral blood mononuclear cells stimulated in vitro with 1 microgram/mL endotoxin, GM-6001 at concentrations > 5 micrograms/mL blocked release of TNF alpha, but did not affect the release of either IL-1 beta or IL-6. GM-6001 also inhibited the release of soluble TNF receptor (p75) from peripheral blood mononuclear cells stimulated with endotoxin and/or TNF alpha. To confirm the role of secreted TNF alpha in endotoxic shock-induced mortality, C57BL/6 mice were challenged with either endotoxin alone (500 micrograms/mouse) or endotoxin (100 ng/mouse) plus D-galactosamine (8 mg/mouse). GM-6001 pretreatment (100 mg/kg) significantly attenuated the 90-minute plasma TNF alpha response in both models and improved survival in mice treated with low-dose endotoxin plus D-galactosamine. However, plasma IL-1 beta and IL-6 concentrations at 90 min after endotoxin treatment were unaffected by GM-6001 following lethal endotoxin challenge, confirming the in vivo specificity of this matrix metalloproteinase inhibitor for TNF alpha processing. These findings demonstrate that a novel inhibitor of matrix metalloproteinases can prevent the release of TNF alpha both in vitro and in vivo, and can abrogate the harmful sequelae of endotoxemic shock.

Stimulation of hepatocyte System y(+)-mediated L-arginine transport by an inflammatory agent.

BACKGROUND: Arginine participates in several distinct metabolic pathways, including polyamine and nitric oxide biosynthesis. Normally, arginine is effectively sequestered from the hepatocyte intracellular space by the low basal activity of membrane transport system y+. This has implications for the subsequent metabolism of arginine and for hepatic arginine requirements during a septic insult. We investigated the influence of tumor necrosis factor (TNF) on the activity of System y(+)-mediated hepatocyte arginine transport employing hepatic plasma membrane vesicles (HPMVs). METHODS: Rats were treated with a single intraperitoneal injection of TNF (50 or 150 micrograms/kg body weight) for 2, 4, or 24 hours, and HPMVs were prepared by Percoll density gradient centrifugation. Vesicle purity was established by assay of enzyme markers. Vesicle arginine transport activity was evaluated by measurement of tritiated arginine uptake employing a rapid mixing-filtration technique. RESULTS: Arginine transport by HPMVs was entirely independent of sodium and consisted of saturable and nonsaturable components. Prior treatment with TNF resulted in a time- and dose-dependent stimulation of saturable transport within 2 hours and a return to basal levels after 24 hours. Nonsaturable uptake was unchanged. Inhibition analysis indicated that the TNF-induced increase in saturable arginine transport activity was mediated by an increase in System y+. Kinetic analysis revealed that accelerated transport was caused by a 78% increase in the maximal velocity of transport without alteration in transport affinity. CONCLUSIONS: In vivo treatment with TNF results in a rapid stimulation of saturable, System y(+)-mediated arginine transport in the liver. This TNF-induced stimulation of hepatic arginine transport may serve to increase the normally restricted availability of extrahepatic arginine to the hepatocyte intracellular space during a septic insult to support important arginine-dependent pathways in the liver.

Endotoxin stimulates arginine transport in pulmonary artery endothelial cells.

BACKGROUND: The pulmonary endothelium plays an important role in the metabolism of the amino acid arginine, the exclusive precursor molecule for nitric oxide (NO). Despite decreased circulating arginine levels, endothelial NO production is elevated during endotoxemia. However, the regulation of pulmonary artery endothelial arginine transport has not been studied. We hypothesized that endotoxin stimulates carrier-mediated arginine transport by the pulmonary endothelium. METHODS: The relative contributions of the various transport systems to total arginine transport by porcine pulmonary artery endothelial cells (PAECs) was determined by assaying the uptake of 3H-L-arginine in the presence or absence of Na+. PAECs were then incubated with various concentrations of Escherichia coli endotoxin, and y(+)-mediated arginine transport was measured at different time points thereafter. Kinetic studies were performed over a range of arginine concentrations to determine changes in transport affinity and maximum rate of metabolism. To address the role of RNA and protein synthesis in the increased transport, uptake was measured after exposure of cells to the transcriptional inhibitor actinomycin D and the protein synthesis inhibitor cycloheximide. RESULTS: Most (75%) of arginine transport by PAECs was mediated by the high-affinity Na(+)-independent transport system y+. Endotoxin stimulated y(+)-mediated arginine transport by PAECs twofold to fivefold, a response that was time and dose dependent. The accelerated transport was detectable within 2 hours and maximal at 12 hours. Kinetic studies revealed that the accelerated arginine transport was the result of a 68% increase in the maximal transport velocity (1519 +/- 65 pmol/mg protein/30 sec in endotoxin-treated cells vs 903 +/- 96 in control cells; p < 0.01) without a change in transport affinity. The endotoxin-mediated increase in arginine uptake was abrogated by actinomycin D and cycloheximide. CONCLUSIONS: Endotoxin stimulates Na(+)-independent arginine transport by PAECs through a process that requires de novo RNA and protein synthesis, possibly of the transporter itself. This response may be designed to support arginine-dependent biosynthetic pathways in the lung during septic states.

Effects of intravenous nutrition on tumor growth and host immunocompetence in malnourished animals.

To evaluate the effects of oral and intravenous nutritional repletion on tumor growth and host immunocompetence in malnourished animals, 60 adult purified protein derivative (PPD) positive Buffalo rats were inoculated with Morris hepatoma 5123 and were fed a regular diet for 14 days. All animals then were switched to a high carbohydrate, protein-free diet for the next 14 days, at which time only 30% of the animals remained PPD positive. Rats then were divided into three groups: group I underwent superior vena cava catheterization and received a constant infusion of 25% dextrose--4.25% amino acid solution; group II was switched to the regular protein diet orally ad libitum; and group III remained on the oral protein-free diet. PPD reactivities were measured prior to death 7 days later. Group I animals gained an average of 14 gm of body weight, and 91% of the animals were PPD positive. Group II animals lost an average of 17 gm of body weight, but 78% of the animals were PPD positive. Group III animals lost an average of 23 gm of body weight, and only 12% of the animals remained PPD positive. Absolute tumor weight and tumor weight: body weight ratios were not significantly different among the three groups of animals. Provision of adequate nutrition intravenously to malnourished tumor-bearing animals restores body weight and host immunocompetence without adversely stimulating tumor growth out of proportion to growth of the host.