Biochemical engineering for elemental sulfur from flue gases through multi-enzymatic based approaches - A review

Flue gases are the gases which are produced from industries related to chemical manufacturing, petrol refineries, power plants and ore processing plants. Along with other pollutants, sulfur present in the flue gas is detrimental to the environment. Therefore, environmentalists are concerned about its removal and recovery of resources from flue gases due to its activation ability in the atmosphere to transform into toxic substances. This review is aimed at a critical assessment of the techniques developed for resource recovery from flue gases. The manuscript discusses various bioreactors used in resource recovery such as hollow fibre membrane reactor, rotating biological contractor, sequential batch reactor, fluidized bed reactor, entrapped cell bioreactor and hybrid reactors. In conclusion, this manuscript provides a comprehensive analysis of the potential of thermotolerant and thermophilic microbes in sulfur removal. Additionally, it evaluates the efficacy of a multi-enzyme engineered bioreactor in this process. Furthermore, the study introduces a groundbreaking sustainable model for elemental sulfur recovery, offering promising prospects for environmentally-friendly and economically viable sulfur removal techniques in various industrial applications.

Recent advances in remediation strategies for mitigating the impacts of emerging pollutants in water and ensuring environmental sustainability

The proliferation of emerging pollutants (EPs), encompassing a range of substances such as phthalates, phenolics, pharmaceuticals, pesticides, personal care products, surfactants, and disinfection agents, has become a significant global concern due to their potential risks to the environment and human well-being. Over the past two decades, numerous research studies have investigated the presence of EPs in wastewater and aquatic ecosystems, with the United States Environmental Protection Agency (USEPA) categorizing these newly introduced chemical compounds as emerging contaminants due to their poorly understood impact. EPs have been linked to adverse health effects in humans, including genotoxic and cytotoxic effects, as well as conditions such as obesity, diabetes, cardiovascular disease, and reproductive abnormalities, often associated with their estrogenic action. Microalgae have shown promise in the detoxification of both inorganic and organic contaminants, and several large-scale microalgal systems for wastewater treatment have been developed. However, the progress of algal bioremediation can be influenced by accidental contaminations and operational challenges encountered in pilot-scale research. Microalgae employ various processes, such as bioadsorption, biouptake, and biodegradation, to effectively remediate EPs. During microalgal biodegradation, complex chemical compounds are transformed into simpler substances through catalytic metabolic degradation. Integrating algal bioremediation with existing treatment methodologies offers a viable approach for efficiently eliminating EPs from wastewater. This review focuses on the use of algal-based biological remediation processes for wastewater treatment, the environmental impacts of EPs, and the challenges associated with implementing algal bioremediation systems to effectively remove emerging pollutants.

Current research trends on cosmetic microplastic pollution and its impacts on the ecosystem: A review

Since the advent of microplastics, it has become a vital component, directly or indirectly, in our daily lives. With advancements in their use, microplastics have become an integral part of personal care, cosmetics, and cleaning products (PCCPs) and emerged as a domestic source of environmental pollution. Over the years, researchers have ascertained the harmful effects of microplastics on the environment. In this context, the assessment and monitoring of microplastics in PCCPs require considerable attention. In addition, it raises concern regarding the need to develop innovative, sustainable, and environmentally safe technologies to combat microplastic pollution. Therefore, this review is an endeavor to uncover the fate, route and degradation mechanism of cosmetic microplastics. In addition, the major technological advancement in cosmetic microplastic removal and the steps directed toward mitigating cosmetic microplastic pollution are also discussed.

Technological advances in the production of carotenoids and their applications- A critical review

Carotenoids are naturally occurring pigments that are widely distributed in algae, fungi, bacteria, and plants. Carotenoids play a significant role in the food, feed, cosmetic, nutraceutical, and pharmaceutical industries. These pigments are effectively considered as a health-promoting compounds, which are widely used in our daily diet to reduce the risk of chronic diseases such as cardiovascular diseases, cancer, acute lung injury, cataracts, neural disorders, etc. In this context, this review paper demonstrates the synthesis of carotenoids and their potential application in the food and pharmaceutical industries. However, the demand for carotenoid production is increasing overtime, and the extraction and production are expensive and technically challenging. The recent developments in carotenoid biosynthesis, and key challenges, bottlenecks, and future perspectives were also discussed to enhance the circular bioeconomy.

Fatigue Problems in Dacron Vascular Grafts

In our own case as well as in nine others of pseudoaneurysm caused probably by material fatigue in Wesolowsky-Weavenit® bifurcation prostheses there is a striking similarity with regard to manufacturer, year of implantation and regional distribution.

We discuss the causes and consequences of this late vascular-surgical complication.

Identifying the Long-Term Role of Inducible Nitric Oxide Synthase after Contusive Spinal Cord Injury Using a Transgenic Mouse Model

Inducible nitric oxide synthase (iNOS) is a potent mediator of oxidative stress during neuroinflammation triggered by neurotrauma or neurodegeneration. We previously demonstrated that acute iNOS inhibition attenuated iNOS levels and promoted neuroprotection and functional recovery after spinal cord injury (SCI). The present study investigated the effects of chronic iNOS ablation after SCI using inos-null mice. iNOS^-/- knockout and wild-type (WT) control mice underwent a moderate thoracic (T8) contusive SCI. Locomotor function was assessed weekly, using the Basso Mouse Scale (BMS), and at the endpoint (six weeks), by footprint analysis. At the endpoint, the volume of preserved white and gray matter, as well as the number of dorsal column axons and perilesional blood vessels rostral to the injury, were quantified. At weeks two and three after SCI, iNOS^-/- mice exhibited a significant locomotor improvement compared to WT controls, although a sustained improvement was not observed during later weeks. At the endpoint, iNOS^-/- mice showed significantly less preserved white and gray matter, as well as fewer dorsal column axons and perilesional blood vessels, compared to WT controls. While short-term antagonism of iNOS provides histological and functional benefits, its long-term ablation after SCI may be deleterious, blocking protective or reparative processes important for angiogenesis and tissue preservation.

Comparative oxidative stress, metallothionein induction and organ toxicity following chronic exposure to arsenic, lead and mercury in rats

Globally, arsenic, mercury and lead constitutes as the three most hazardous environmental toxicants perturbing imbalance in pro—oxidant and antioxidant homeostasis. Individual toxicity of these environmental toxicants is well known but there is lack of comparative data on variables indicative of oxidative stress. We thus investigated the effects of chronic exposure to sodium arsenite, mercuric chloride and lead acetate on blood and tissue oxidative stress, metal concentration and metallothionein (MT) contents. Male rats were exposed to sodium arsenite, mercuric chloride and lead acetate (0.05 mg/kg each, orally, once daily) for 6 months. Arsenic, mercury and lead exposure led to a significant inhibition of blood δ—aminolevulinic acid dehydratase (ALAD) activity and glutathione level supported by increased thiobarbituric acid reactive substance (TBARS). The level of inhibition was more pronounced in case of lead followed by mercury and arsenic. These metals/ metalloid significantly increased reactive oxygen species (ROS), thiobarbituric acid reactive substances (TBARS) and glutathione peroxidase (GPx) activity accompanied by a decreased superoxide dismutase (SOD), catalase and reduced and oxidized glutathione (GSH and GSSG) levels in blood and tissues. Mercury alone produced a significant induction of hepatic and renal MT concentrations. Serum transaminases, lactate dehydrogenase and alkaline phosphatase activities increased significantly on exposure to arsenic and mercury exposure suggesting liver injury which was less pronounced in case of lead exposure. These biochemical alterations were supported by increased arsenic, mercury and lead concentrations in blood and soft tissues. The present study suggests that exposure to sodium arsenite and mercuric chloride lead to more pronounced oxidative stress and hepatotoxicity while lead acetate caused significant alterations in haem synthesis pathway compared to two other thiol binding metal/metalloid.

Alpha-lipoic acid protects oxidative stress, changes in cholinergic system and tissue histopathology during co-exposure to arsenic-dichlorvos in rats

We investigated protective efficacy of α-lipoic acid (LA), an antioxidant against arsenic and DDVP co-exposed rats. Biochemical variables suggestive of oxidative stress, neurological dysfunction, and tissue histopathological alterations were determined. Male rats were exposed either to 50 ppm sodium arsenite in drinking water or in combination with DDVP (4 mg/kg, subcutaneously) for 10 weeks. α-Lipoic acid (50mg/kg, pos) was also co-administered in above groups. Arsenic exposure led to significant oxidative stress along, hepatotoxicity, hematotoxicity and altered brain biogenic amines levels accompanied by increased arsenic accumulation in blood and tissues. These altered biochemical variables were supported by histopathological examinations leading to oxidative stress and cell death. These biochemical alterations were significantly restored by co-administration of α-lipoic acid with arsenic and DDVP alone and concomitantly. The results indicate that arsenic and DDVP induced oxidative stress and cholinergic dysfunction can be significantly protected by the supplementation of α-lipoic acid.

Combining Neurotrophin-Transduced Schwann Cells and Rolipram to Promote Functional Recovery from Subacute Spinal Cord Injury

Following spinal cord injury (SCI), both an inhibitory environment and lack of intrinsic growth capacity impede axonal regeneration. In a previous study, prevention of cyclic adenosine monophosphate (AMP) hydrolysis by the phosphodiesterase-4 inhibitor rolipram, in combination with Schwann cell (SC) grafts, promoted significant supraspinal and proprioceptive fiber growth and/or sparing and improved locomotion. In another study, transplanted SCs transduced to generate a bifunctional neurotrophin (D15A) led to significant increases in graft SCs and axons, including supraspinal and myelinated axons. Here we studied the growth and myelination of local and supraspinal axons and functional outcome following the combination of rolipram administration and neurotrophin-transduced SC implantation after SCI. Rolipram was administered subcutaneously for 4 weeks immediately after contusion at vertebral T8 (25.0-mm weight drop, MASCIS impactor). GFP or GFP-D15A-transduced SCs were injected into the injury epicenter 1 week after SCI. GFP-D15A SC grafts and GFP SC grafts with rolipram contained significantly more serotonergic fibers compared to GFP SCs. SC myelinated axons were increased significantly in GFP SC with rolipram-treated animals compared to animals receiving SCI alone. Rolipram administered with either GFP or GFP-D15A SCs significantly increased numbers of brain stem-derived axons below the lesion/implant area and improved hindlimb function. Compared to the single treatments, the combination led to the largest SC grafts, the highest numbers of serotonergic fibers in the grafts, and increased numbers of axons from the reticular formation below the lesion/implant area and provided the greatest improvement in hindlimb function. These findings demonstrate the therapeutic potential for a combination therapy involving the maintenance of cyclic AMP levels and neurotrophin-transduced SCs to repair the subacutely injured spinal cord.

Arsenic and lead induced free radical generation and their reversibility following chelation

Health hazards caused by heavy metals have become a great concern to the population. Lead and arsenic are one of the most important current global environmental toxicants. Their toxic manifestations are being considered caused primarily due to the imbalance between pro-oxidant and antioxidant homeostasis and also due to a high affinity of these metals for thiol groups on functional proteins. They also interfere with a number of other body functions and are known to affect central nervous system (CNS), hematopoietic system, liver and kidneys and produce serious disorders. They produce both acute and chronic poisoning, of which chronic poisoning is more dangerous as its very difficult to revert back to normal condition after chronic exposure to these insidious metals present in our life. Despite many years of research, we are still far from an effective treatment of chronic plumbism and arsenicosis. Current approved treatment lies in the administration of chelating agents that forms an insoluble complex with the metal and removes it. They have been used clinically as antidotes for treating acute and chronic poisoning. The most widely used chelating agents are calcium disodium ethylenediamine tetra acetic acid (CaNa2EDTA), D-penicillamine and British anti-lewisite (BAL). Meso 2,3 dimercaptosuccinic acid (DMSA), an analogue of BAL, has been tried successfully in animals as well as in humans. But it is unable to remove the metal from intracellular sites. Effective chelation therapy for intoxication by heavy metals depends on whether the chelating agents are able to reach the intracellular site where the heavy metal is firmly bound. One of the important approaches has been the use of combination therapy. This includes use of structurally different chelators or a combination of an adjuvant/ antioxidant/ herbal extracts and a chelator to provide better clinical/ biochemical recovery. A number of other strategies have been suggested to minimize the numerous problems. This article presents the recent development made in this area with possible directions for future research.

Identifying the long-term role of iNOS in contusive spinal cord injury (SCI) using a transgenic mouse model (100.14)

The inflammatory mediator iNOS is thought to play an important role in the pathophysiology of SCI. Specific inhibition of iNOS is beneficial after acute SCI, but little is known about its role over longer post-injury periods. The current study was carried out to assess the role of iNOS after contusive SCI through the use of chronic iNOS inhibition by a knockout mouse approach. Wild type (WT) and iNOS(−/−) mice were injured and then subjected to behavioral testing (BMS) and histological evaluation of healthy white and gray matter tissue volumes. Behaviorally, iNOS(−/−) mice displayed a significantly faster recovery of function compared to WT in open-field locomotion during the first 4 wk (WT 2.2±0.2, iNOS(−/−) 3.38±0.43; p < 0.05).At the endpoint of the experiment (8wk) however, iNOS(−/−) mice showed a trend towards worsened functional outcome. Histological analysis revealed that i-NOS(−/−) mice had a significant decrease in the volumes of both healthy gray (53%) and healthy white matter (15%) as compared to WT. The present study shows that acute inhibition of iNOS could be behaviorally beneficial after SCI, however, chronic inhibition likely hampers important wound healing functions of NO, leading to a lack of efficacy at later stages.

FUNDING: The Miami Project to Cure Paralysis, The Buoniconti Fund, The US Army Medical Research and Material Command

Cyclooxygenase-2 is involved in HIV-1 Tat-induced inflammatory responses in the brain

Cyclooxygenase (COX)-2, a rate-limiting enzyme for prostanoid synthesis, can be involved in inflammatory-mediated cytotoxicity. Although the contribution of COX-2 to peripheral inflammation is well understood, its role in brain inflammation is not fully recognized. In particular, COX-2 involvement in inflammatory responses induced by HIV proteins in the central nervous system is not known. Therefore, the present study focused on COX-2 expression and its role in modulating the expression of brain inflammatory-related genes following exposure to the HIV-1 transactivating protein Tat. Intrahippocampal injections of Tat induced dose-dependent upregulation of COX-2 mRNA and protein levels in C57BL/6 mice. COX-2 immunoreactivity was primarily localized in microglial cells and astrocytes. Tat-induced COX-2 expression was partially prevented by pyrrolidine dithiocarbamate, a potent antioxidant and an inhibitor of the transcription factor, nuclear factor kappaB. Most importantly, administration of the COX-2 inhibitor NS-398 attenuated Tat-mediated upregulation of mRNA and protein expression of inflammatory mediators, such as monocyte chemoattractant protein-1, interleukin-1beta, tumor necrosis factor-alpha, and inducible nitric oxide synthase. Moreover, treatment with NS-398 significantly attenuated Tat-induced activation of microglial cells. These results provide evidence that COX-2 overexpression can modulate induction of brain inflammatory mediators in response to HIV-1 Tat protein. Such alterations may play an important role in the development of brain inflammatory reactions in HIV-infected patients and contribute to the development of neurological complications in the course of HIV-1 infection.

HIV-1 Tat protein-induced alterations of ZO-1 expression are mediated by redox-regulated ERK 1/2 activation

HIV-1 Tat protein plays an important role in inducing monocyte infiltration into the brain and may alter the structure and functions of the blood-brain barrier (BBB). The BBB serves as a frontline defense system, protecting the central nervous system from infected monocytes entering the brain. Therefore, the aim of the present study was to examine the mechanisms of Tat effect on the integrity of the BBB in the mouse brain. Tat was injected into the right hippocampi of C57BL/6 mice and expression of tight junction protein zonula occludens-1 (ZO-1) was determined in control and treated mice. Tat administration resulted in decreased mRNA levels of ZO-1 and marked disruption of ZO-1 continuity. These changes were associated with accumulation of inflammatory cells in brain tissue of Tat-treated mice. Further experiments indicated that Tat-mediated alterations of redox-related signaling may be responsible for decreased ZO-1 expression. Specifically, injections with Tat resulted in activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and pretreatment with U 0126, a specific inhibitor of ERK kinase, effectively ameliorated the Tat-induced diminished ZO-1 levels. In addition, administration of N-acetylcysteine (NAC), a precursor of glutathione and a potent antioxidant, attenuated both Tat-induced ERK 1/2 activation and alterations in ZO-1 expression. These results indicate that Tat-induced oxidative stress can play an important role in affecting the integrity of the BBB through the ERK 1/2 pathway.

Mechanisms of the blood-brain barrier disruption in HIV-1 infection

(1) Alterations of brain microvasculature and the disruption of the blood-brain barrier (BBB) integrity are commonly associated with human immunodeficiency virus type 1 (HIV-1) infection. These changes are most frequently found in human immunodeficiency virus-related encephalitis (HIVE) and in human immunodeficiency virus-associated dementia (HAD). (2) It has been hypothesized that the disruption of the BBB occurs early in the course of HIV-1 infection and can be responsible for HIV-1 entry into the CNS. (3) The current review discusses the mechanisms of injury to brain endothelial cells and alterations of the BBB integrity in HIV-infection with focus on the vascular effects of HIV Tat protein. In addition, this review describes the mechanisms of the BBB disruption due to HIV-1 or Tat protein interaction with selected risk factors for HIV infection, such as substance abuse and aging.

Proinflammatory synergism of ethanol and HIV-1 Tat protein in brain tissue

Human immunodeficiency virus type 1 (HIV-1) Tat protein is a potent transactivator of viral replication. It is actively released from HIV-infected cells and has been shown to induce cell injury effects. Alcohol abuse is a risk factor of HIV infection and we hypothesize that alcohol and Tat may interact in an additive or synergistic fashion to influence molecular processes which can contribute to their toxic effects. To study this possibility, we investigated the effects of two intraperitoneal injections of ethanol (EtOH, 3 g/kg each, 16 h apart) and a single intracerebral injection of Tat (25 microg/microl into the right hippocampus, injected 12 h after the first EtOH injection) on generation of cellular oxidative stress, DNA binding activity of redox-responsive transcription factors, and induction of inflammatory genes in the hippocampus and corpus striatum of mouse brain. As compared to control animals, treatment with EtOH plus Tat resulted in increased production of reactive oxygen species in both brain regions. In addition, DNA binding activities of nuclear factor-kappaB (NF-kappaB) and CREB in both brain regions and SP-1 in the hippocampus were more pronounced in mice injected with Tat plus EtOH as compared to the effects of Tat or EtOH alone. Among studied inflammatory genes, induction of IL-1beta and MCP-1 was potentiated in animals injected with EtOH plus Tat. These results indicate that Tat and EtOH can cross-amplify their cellular effects, leading to alterations of redox-regulated inflammatory pathways in the brain. Such potentiation of proinflammatory stimulation may further contribute to CNS pathology in HIV-infected patients who are alcohol abusers.

Nicotine attenuates oxidative stress, activation of redox-regulated transcription factors and induction of proinflammatory genes in compressive spinal cord trauma

Pathophysiology of neurodegeneration following spinal cord injury (SCI) involves alterations of cellular redox status, activation of transcription factors and induction of proinflammatory genes. In addition, recent evidence indicates that nicotine can induce potent neuroprotective effects. To study the influence of nicotine on the redox signaling pathways in relationship to SCI, moderate contusions of spinal cords at the level of T-10 were induced in rats treated or untreated with nicotine. Cellular oxidative stress, DNA binding activity of redox-responsive transcription factors (AP-1, NF-kappaB and CREB) as well as mRNA levels of inflammatory genes (MCP-1 and TNF-alpha) were determined in the thoracic and lumbar regions of the spinal cords. Nicotine was administrated 2 h after the SCI in a single i.p. injection at the dose of 0.35, 3.5 or 7 mg/kg, and rats were sacrificed 3 h following such an injection. Spinal cord trauma was associated with a significant increase in oxidative stress, and activation of NF-kappaB, AP-1 and CREB, as well as overexpression of MCP-1 and TNF-alpha in both the thoracic and lumbar regions. Nicotine administration following the SCI markedly attenuated, especially in the lumbar region, these oxidative and proinflammatory responses. These protective effects of nicotine were fully reversed by inhibition of neuronal nicotinic receptors by mecamylamine. The present results indicate that nicotine administration can attenuate the oxidative injury to spinal cords and suggest that neuronal nicotinic receptors can be attractive targets for neuroprotective therapy.

HIV-1 Tat protein upregulates inflammatory mediators and induces monocyte invasion into the brain

Impaired inflammatory functions may be critical factors in the mechanisms by which HIV-1 enters the CNS. Evidence indicates that a viral gene product, the protein Tat, can markedly contribute to these effects. In the present study we tested the hypothesis that Tat can upregulate the expression of inflammatory cytokines and adhesion molecules and facilitate the entry of monocytes into the brain. Expression of inflammatory mediators such as monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-alpha), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) was assessed in C57BL/6 mice injected with Tat(1-72) into the right hippocampus. In the Tat(1-72)-injected groups, mRNA and protein levels of MCP-1, TNF-alpha, VCAM-1, and ICAM-1 were markedly elevated compared to those in control animals. The most pronounced changes were observed in and around the injected hippocampus. Double-labeling immunohistochemistry demonstrated that inflammatory proteins were primarily expressed in activated microglial cells and perivascular cells. In addition, astrocytes and endothelial cells were susceptible to Tat(1-72)-induced inflammatory responses. These changes were associated with a substantial infiltration of monocytes into the brain. These data demonstrate that intracerebral administration of Tat can induce profound proinflammatory effects in the brain, leading to monocyte infiltration.

Methamphetamine-induced TNF-alpha gene expression and activation of AP-1 in discrete regions of mouse brain: potential role of reactive oxygen intermediates and lipid peroxidation

Cellular and molecular mechanisms of methamphetamine (METH)-induced neurotoxicity may involve alterations of cellular redox status and induction of inflammatory genes. To study this hypothesis, molecular signaling pathways of METH-induced inflammatory responses via activation of redox-sensitive transcription factors were investigated in discrete regions (corpus striatum, frontal cortex, and hippocampus) of mouse brain. Intraperitoneal injection of METH at a dose of 10 mg/kg body weight resulted in a significant increase in oxidative stress, as measured by 2,7-dichlorofluorescein (DCF) fluorescence assay, thiobarbituric acid-reactive substances (TBARS), and total glutathione levels. Glutathione peroxidase activity was also significantly increased after METH exposure. In addition, DNA binding activity of activator protein-1 (AP-1), a redox-responsive transcription factor, was increased in all studied brain regions in response to METH treatment. Because AP-1 is known to regulate expression of inflammatory genes, levels of TNF-alpha mRNA were also studied. Expression of the tumor necrosis factor-alpha (TNF-alpha) gene was induced 3 h after METH injection and remained elevated for up to 6 h of METH exposure. In addition, stimulation of the TNF-alpha gene was associated with increased TNF-a protein production in the frontal cortex. These results suggest that METH-induced disturbances in cellular redox status and that activation of AP-1 can play a critical role in signaling pathways leading to upregulation of inflammatory genes in vivo. Furthermore, these data provide evidence for the role of oxidative stress in the neurotoxic effects of METH.

HIV-Tat protein induces oxidative and inflammatory pathways in brain endothelium

Impaired function of the brain vasculature might contribute to the development of HIV-associated dementia. For example, injury or dysfunction of brain microvascular endothelial cells (BMEC) can lead to the breakdown of the blood-brain barrier (BBB) and thus allow accelerated entry of the HIV-1 virus into the CNS. Mechanisms of injury to BMEC during HIV-1 infection are not fully understood, but the viral gene product Tat may be, at least in part, responsible for this effect. Tat can be released from infected perivascular macrophages in the CNS of patients with AIDS, and thus BMEC can be directly exposed to high concentrations of this protein. To study oxidative and inflammatory mechanisms associated with Tat-induced toxicity, BMEC were exposed to increasing doses of Tat1-72, and markers of oxidative stress, as well as redox-responsive transcription factors such as nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1), were measured. Tat1-72 treatment markedly increased cellular oxidative stress, decreased levels of intracellular glutathione and activated DNA binding activity and transactivation of NF-kappaB and AP-1. To determine if Tat1-72 can stimulate inflammatory responses in brain endothelium in vivo, expression of monocyte chemoattractant protein-1 (MCP-1), an NF-kappaB and AP-1-dependent chemokine, was studied in brain tissue in mice injected with Tat1-72 into the right hippocampus. Tat1-72 markedly elevated the MCP-1 mRNA levels in brain tissue. In addition, a double immunohistochemistry study revealed that MCP-1 protein was markedly overexpressed on brain vascular endothelium. These data indicate that Tat1-72 can induce redox-related inflammatory responses both in in vitro and in vivo environments. These changes can directly lead to disruption of the BBB. Thus, Tat can play an important role in the development of detrimental vascular changes in the brains of HIV-infected patients.

Methamphetamine potentiates HIV-1 Tat protein-mediated activation of redox-sensitive pathways in discrete regions of the brain

Tat is a major regulatory protein encoded by human immunodeficiency viral genome, which has been implicated in the pathogenesis of HIV infection, including neurologic complications associated with this disease. In addition, drug abuse has been identified as a major risk factor of HIV infection. We hypothesize that abusive drugs, such as methamphetamine (METH), can directly influence specific molecular processes that can further contribute to toxic effects of Tat. To elucidate the molecular signaling pathways of Tat- and/or METH-induced toxicity, we investigated the effects of a single injection of Tat (25 microg/microl into the right hippocampus) and/or METH (10 mg/kg, intraperitoneally) on the generation of cellular oxidative stress, DNA-binding activity of specific redox-responsive transcription factors, and expression of inflammatory genes. Administration of Tat or METH resulted in stimulation of cellular oxidative stress and activation of redox-regulated transcription factors in the cortical, striatal, and hippocampal regions of the mouse brain. In addition, DNA-binding activities of NF-kappaB, AP-1, and CREB in the frontal cortex and hippocampus were more pronounced in mice injected with Tat plus METH compared to the effects of Tat or METH alone. Intercellular adhesion molecule-1 gene expression also was upregulated in a synergistic manner in cortical, striatal, and hippocampal regions in mice which received injections of Tat combined with METH compared to the effects of these agents alone. Moreover, synergistic effects of Tat plus METH on the tumor necrosis factor-alpha and interleukin-1beta mRNA levels were observed in the striatal region. These results indicate that Tat and METH can cross-amplify their cellular effects, leading to alterations of redox-regulated inflammatory pathways in the brain. Such synergistic proinflammatory stimulation may have significant implications in HIV-infected patients who abuse drugs.

Methamphetamine activates DNA binding of specific redox-responsive transcription factors in mouse brain

Cellular oxidative stress and alterations in redox status can be implicated in methamphetamine (METH)-induced neurotoxicity. To elucidate the molecular signaling pathways of METH-induced neurotoxicity, we investigated the effects of a single intraperitoneal injection of METH (1.0, 10, or 20 mg/kg) on DNA-binding activity of specific redox-sensitive transcription factors in mouse brain. Transcription factors studied included activator protein-1 (AP-1), nuclear factor-kappaB (NF-kappaB), cAMP-responsive element-binding protein (CREB), SP-1, and signal transducers and activators of transcription (STAT1 and STAT3). Significant and dose-dependent inductions of AP-1 and CREB DNA-binding activities were observed in four different regions (striatum, frontal cortex, hippocampus, and cerebellum) isolated from the brains of mice injected with METH. However, injections with METH did not affect DNA binding activities of NF-kappaB, SP-1, STAT1, and STAT3. These results suggest that METH-induced oxidative stress may trigger the molecular signaling pathways via specific and selective activation of AP-1 and CREB.

Spinal cord protection in descending and thoracoabdominal aortic surgery--the role of distal perfusion

The use of distal perfusion in descending thoracic and thoracoabdominal aortic surgery remains a controversial issue. Few mainly retrospective studies which directly compare simple clamping with distal perfusion are available. The aim of the present study was such a comparison in an own series of descending and thoracoabdominal aortic replacement. The records of 29 patients who underwent descending or thoracoabdominal aortic replacement between 1988 and 1994 were retrospectively reviewed. Patients were divided into two groups. Group I consisted of 14 patients who received aortic replacement using simple clamping, group II was represented by 15 patients who were operated with distal perfusion techniques. In group II left heart bypass with a centrifugal pump was used in 3 patients, and partial cardiopulmonary bypass with a roller pump in 12 patients. The paraplegia/paraparesis rate was 28.6% in group I and 0.0% in group II (p = 0.0258). There were no statistically significant differences regarding surgical revision for bleeding (14.3% in group I, 14.0% in group II), postoperative renal failure (14.3% in group I 13.3% in group II), postoperative ventilator dependence (9.0 days in group I, 11.2 days in group II), rate of postoperative multisystem organ failure (26.7% in group I, 33.3% in group II), length of stay in the ICU (13.6 days in group I and 13.9 days in group II), and 30-day mortality (21.4% in group I and 33.3% in group II). Methods of distal perfusion in comparison to simple clamping can lead to a lower paraplegia/paraparesis rate in descending and thoracoabdominal aortic surgery.

Predictors of short-term survival after helicopter rescue

The purpose of the present retrospective study was to identify easily obtainable predictors of short-term outcome for emergency victims treated by a physician-staffed helicopter emergency medical system (HEMS). The study was conducted at the HEMS unit 'Christophorus 1' based at Innsbruck, Austria. Outcomes for 2139 patients rescued in primary missions during a 3-year period from 1 January 1989 to 31 December 1991 were included in the study. The majority of missions were in response to sports accidents, although missions included a wide spectrum of emergencies. Data were obtained from the 'Christophorus 1' operation protocols and by written, personal, or telephone request from admitting hospitals. Eleven parameters selected from the HEMS flight logs were tested for their predictive value on survival following helicopter rescue. In a univariate analysis, the cause of the emergency, time at the scene, total duration of the emergency mission, patient age, patient gender, severity of the emergency using the National Advisory Committee of Aeronautics (NACA) scoring system, state of consciousness, respiratory status and patient circulatory status each had a statistically significant influence on survival up to 90 days following the emergency. Flight time to the scene and the original specialty of the additionally trained emergency physician had no significant influence on outcome. Multivariate analysis using the Cox proportional hazards model revealed that severity of the emergency by the seven-level NACA scale (P = 0.0001), initial respiratory status (P = 0.0001), time at the scene (P = 0.0108), patient age (P = 0.0047) and patient gender (P = 0.0477) were each independent predictors of short-term survival following physician-staffed helicopter rescue. We conclude that the parameters described above can be used in an initial predictive assessment by the flight physician and the admitting institution.

[Video-controlled, retroperitoneoscopic, lumbar sympathectomy and sympathicotomy]

Six patients with arterial occlusions of the legs underwent VRLS: a small incision is made in the flank, the retroperitoneum pushed aside with a 1.5-1-balloon catheter, the lumbar sympathicus endoscopically severed and/or partially excised with video assistance. The intervention was successful in all cases. Excised parts of the sympathetic trunk were demonstrated histologically in four cases. One case of severe bleeding from a lumbar artery was stopped endoscopically, and one patient underwent additional open resection of 2 cm of the sympathetic trunk. Postoperative intestinal paralysis lasted a mean of two days, and hospitalization five days. VRLS has several disadvantages for the surgeon, while its lesser strain and earlier rehabilitation are a definite advantage for the patient.

[Thoracoscopic sympathicotomy]

Surgical endoscopic endothoracic denervation (severing the n. vagus and the sympathetic trunk with the nn. splanchnici) was developed by Kux at Innsbruck University Surgical Clinic in the 1950's and applied in thousands of patients with a very wide range of indications. The thoracoscopic sympathicotomy has remained, in the hands of the experienced surgeon, a minor intervention with low complication rate and no mortality. For functional and organic angiopathies as well as for hyperhidrosis of the upper extremities it provides very good early and satisfactory late results.

Graft replacement of post-traumatic thoracic aortic aneurysm: results without bypass or shunting

From 1986 to 1991 13 cases of post-traumatic thoracic aneurysm were treated at our department. All patients had apparent thoracic injury at the time of trauma, and their mean age was 35 years. The mean time between trauma and operation was 3 years and six patients were asymptomatic. In all patients the diagnosis was made by computed tomography and angiography and all post-traumatic thoracic aneurysms were located at the aortic isthmus. No spinal cord protection by bypass or shunting was used during surgery and the clamp-and-repair method with a mean clamping time of 38 min was used in all 13 patients. No renal or neurological complications were observed postoperatively and there were no hospital deaths. The data of 202 patients who had been operated upon for post-traumatic thoracic aneurysms since 1981 have been reviewed with regard to the relationship between spinal cord protection and the incidence of postoperative paraplegia. Different methods of spinal cord protection were used in 121 patients resulting in paraplegia rate of 1.6%. In 81 patients the clamp-and-repair method was used and no case of paraplegia was observed in this group.

[Characteristics of the heart rate of emergency physicians in emergency helicopters]

The heart rate behaviour of 14 emergency doctors was examined in 50 cases of medical emergency service by helicopter. In addition, the subjective stress experienced by the probands was inquired by means of a questionnaire. The alarm and the landing at the site of the emergency resulted in the most marked heart rate increases; also during the period of approaching the patient, his rescue and care, persistent tachycardia could be observed. Recovery began slowly during the return flight, but even 15 minutes after completion of the emergency task the heart rate was still higher than the original value before the alarm had been sounded. Subjectively the total stress was considered to be generally low in the opinion of the emergency doctors. It seems that unconscious mechanisms of repression prevent the actual realistic recording of physical and emotional stress during the emergency service by helicopter.

Chemotherapy of metastatic Merkel cell carcinoma: case report and review of the literature

Merkel cell carcinoma is a skin cancer that bears histologic, ultrastructural, and immunohistochemical resemblance to small cell lung cancer. Although this tumor is often localized and may be treated with wide excision, metastatic Merkel cell carcinoma does appear in 18%-28% of patients and may be aggressive and lethal. We report a case of metastatic Merkel cell carcinoma who responded to treatment with cisplatin/etoposide. Review of the literature reveals that doxorubicin/cyclophosphamide-based regimens and cisplatin-based regimens have been most commonly studied. Complete and partial responses are often achieved although the duration of response tends to be short. Further investigation of chemotherapeutic regimens similar to those used in small cell lung cancer should be undertaken.

Isolated iliac artery aneurysms

Clinical and diagnostic data were collected from 22 men with iliac artery aneurysms treated surgically over a period of 22 years. Their ages ranged from 47 to 80 years (mean 64.0). Eight patients had multiple aneurysms. Thirty isolated iliac artery aneurysms were detected, 20 aneurysms (66.6%) located on the right and 10 (33.3%) on the left side. Twenty-six aneurysms were found in the common iliac artery (86.6%). Fifteen patients were symptomatic (68.2%); rupture occurred in five patients (22.7%), three of whom were initially asymptomatic. Thirteen of 17 patients whose aneurysms did not rupture had a palpable mass (76.4%), and three had bruits in the area of the aneurysm. All 22 patients were subjected to operative procedures. Seventeen patients operated upon electively survived, whereas only three patients who were operated upon after rupture survived. Graft interposition was the most common procedure. All 20 patients who survived after the operation were followed. Two died of myocardial infarction three and five years later, one of cancer six years later, and one of an unknown cause eight years after operation. Iliac artery aneurysms are extremely rare; their diagnosis is very difficult. The mortality rate is two times higher than in aortic aneurysms, once the diagnosis has been established. Therefore elective resection and arterial reconstruction are recommended.

Duodenal fistula after reconstruction of the inferior vena cava with an externally stented PTFE graft

Reconstructions of the inferior vena cava with externally stented grafts may result in erosion and fistulation into an adjacent intestinal segment. Paraprosthetic infection may cause intravascular thrombosis and dissemination of septic thrombi.

Carotid occlusion caused by seat belt trauma

Surgical reconstruction should be considered in patients showing episodes of transient cerebral ischaemia or progressive neurological deterioration secondary to carotid arterial injuries proved by arteriography. Even complete thrombosis of the internal carotid artery may be managed successfully, if thrombectomy and intimal repair are undertaken within some hours after the onset of neurological symptoms. Unger reported a mortality rate of 21% following carotid arterial trauma, 34% of the patients improved if they underwent surgical repair, whereas only 14% of the patients improved if they had ligation or were not treated surgically. Statistical data have shown that both shock and coma are bad prognostic omens and patients presenting with these signs have less than a 50% chance leaving the hospital alive and well, even if they receive optimum emergency management. Although coma has been suggested as a contraindication to carotid repair, review of the literature has shown the data to be too limited to warrant such a conclusion.

Physical assessment of heat insulation rescue foils

For the insulation of hypothermic individuals, aluminium-coated foils are used as rescue blankets and rescue suits, respectively. By measurements on a phantom, the efficiency of these foils was tested. Based on an appropriate physical model results were transferred to the thermal reaction of hypothermic individuals. Following investigations were carried out: rescue foil with different types of clothing, comparison between rescue foil and woolen blanket, "Hibler packing", rescue suit at sudden fall in temperature. Applying these foils and the suit, respectively, a thermal stabilization of the body core is being achieved approximately under realistic conditions. When applying the "Hibler packing", reheating is achieved both with wet and dry clothing.

Direct subclavian-carotid anastomosis for the subclavian steal syndrome

Between 1984 and 1986, 38 patients--25 males and 13 females--underwent treatment for proximal subclavian arteriosclerotic lesions. All of these patients presented with symptoms of the subclavian steal syndrome and 13 (34.2%) had additional claudication of the arm. Preoperative angiography showed distal filling of the subclavian artery via retrograde flow in the vertebral artery. 31 patients (81.5%) had total occlusion of the proximal subclavian artery and 7 (18.5%) presented with severe stenosis. 34 of these lesions were on the left (89.5%) and 4 on the right side (10.5%). Complete cerebral angiography was performed in each patient with emphasis on visualisation of the carotid bifurcation and selective opacification of the aortic arch vessels if indicated. Doppler ultrasound flow measurement in the vertebral artery yielded the basic data which were then used for comparative postoperative evaluation. The operation was performed under general anaesthesia and heparinisation. A shunt was not required while performing the direct end-to-side anastomosis between the transected subclavian and the common carotid artery. Arteriosclerotic plaques in the distal stump of the transected subclavian artery and occasionally the origin of the vertebral artery were dealt with by simple eversion endarterectomy. There was no operative mortality; the postoperative complication rate was 13.1% including palsy of the recurrent nerve in 3 patients, a lymphatic cyst of the neck in one patient and bleeding requiring re-exploration in another. Occlusion of the reconstructed artery or neurologic deficit did not occur. Post operatively all patients were treated with platelet inhibitors. The average follow-up period was 13 months, when the reconstructed arteries were found to be patent in 37 patients (97.4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Primary arteriovenous fistula between the common iliac vessels secondary to aneurysmal disease

Arteriovenous fistulas between the common iliac vessels are rare; at the present time, only 56 cases have been reported. Forty-seven (83.9%) of these fistulas were secondary to either trauma or surgery for herniated intervertebral disks and nine (16.1%) were caused by aneurysmal disease. Physical examination is very difficult because only 30% of the patients with iliac artery aneurysms have palpable masses before rupture; approximately 60% of the patients already have ruptures at the time of diagnosis. Therefore a high degree of suspicion is necessary and early use of angiography is commendable. Surgical intervention consists of closure of the fistula, resection or ligation of the aneurysm, and restoration of vascular continuity. The survival rate after elective resection is 93%, whereas the operative mortality rate in patients operated on for ruptured iliac artery aneurysms is 52%.

Traumatic renal artery occlusion: is late reconstruction advisable?

We report a case of traumatic renal artery occlusion treated successfully by reconstruction several years after the injury. Hypertension resulted in diagnostic investigation by means of excretory urography, computerized tomography, angiography and perfusion scintigraphy. Treatment consisted of a thin-walled polytetrafluoroethylene (Gore-Tex) bypass between the aorta and left renal artery near the hilus. When the patient was discharged from the hospital the creatinine level was normal and blood pressure was 180/90.

Civilian popliteal artery trauma

An 18 year experience involved 36 civilian popliteal artery injuries is described. There were no operative or hospital deaths and the amputation rate was 3.6%. Penetrating traumas accounted for 30.6% and blunt traumas for 69.4%. In 20 patients (55.5%) the popliteal artery injury was associated with fracture and/or dislocation of the long bones and/or the knee joint. The average ischaemic time was 7.3 hours and postoperative angiography was performed in 25 patients (69.4%). Surgical reconstruction of the popliteal artery was accomplished by interposition or bypass of autogenous saphenous vein graft in 29 (80.5%), by saphenous vein patch in 5 (13.9%) and by primary end-to-end anastomosis in 1 (2.8%) and by PTFE prosthesis in 1 patient (2.8%). In all cases with bone fracture and/or dislocation bone stabilization was followed by the vascular procedure. The average time of follow-up was 76 months, 28 patients could be evaluated in the postoperative study: in 25 (89.2%) the reconstruction was patent, in 3 (10.8%) occluded. In 13 patients (46.4%) there was a complete success, 7 had a nerve deficit (25.0%), 3 had a claudication (10.7%), in one patient an amputation was necessary (3.6%) and 4 (14.3%) suffered from miscellaneous skeletal problems. Of the 36 patients originally operated, 29 (80.5%) received anticoagulant therapy for at least one year.

[Aneurysm of the popliteal vein as the source of a lung embolism]

A case of pulmonary embolism secondary to a clinically unsuspected aneurysm of the popliteal vein is presented. The importance of venography in establishing the source of pulmonary emboli is stressed in comparison to other diagnostic investigations such as ultrasonography, computed tomography or pletysmography. The aneurysm was suitable for local venous reconstruction. Previously reported cases are reviewed, etiology, diagnosis and treatment of this uncommon condition are discussed.

[A simple safe system for intra-arterial infusion by pressure-constant cuff compression of the infusion bag with the help of a reducing valve]

We describe a simple and cheap system of intraarterial infusion. It consists exclusively of single parts which are available on the market. A source of pressure is connected with a modified pressure-reduction valve which produces a constant pressure in an attached pressure cuff, respectively in an enclosed infusion-bag, so that a constant flow rate of the infusion is maintained. First clinical experiences with more than hundred angiological patients have shown that this new system has many advantages. In our routine work we had neither functional disturbances nor other complications.

Ein einfaches und sicheres System für die intraarterielle Infusion durch druckkonstante Manschettenkompression des Infusionsbehälters mit Hilfe eines Reduzierventils

Es wird ein einfaches, billiges System für die intraarterielle Infusion vorgestellt, das ausschlieβlich aus Einzelheiten besteht, die im Handel erhältlich sind. An eine Druckquelle wird ein umgebautes Reduzier-ventil angeschlossen, das in einer angekoppelten Druckmanschette bzw. dem darin liegenden Infusionsbeutel einen konstanten Druck von 300 mmHg erzeugt, wodurch eine weitgehend konstante Flowrate der Infusionslösung erreicht wird. Erste klinische Erfahrungen an über hundert angiologischen Patienten bestätigen, daβ das System eine Reihe von Vorteilen gegenüber gebräuchlichen Vorrichtungen aufweist. Es traten im klinischen Routinebetrieb weder Funktionsstörungen noch Komplikationen auf.