Asymptomatic Late-phase Radiographic Changes Among Chest-Wall Patients Are Associated With a Proton RBE Exceeding 1.1

PURPOSE

Clinical practice assumes a fixed proton relative biological effectiveness (RBE) of 1.1, but in vitro experiments demonstrate higher RBEs at the distal edge of the proton spread-out Bragg peak, that is, in a region that falls within the lung for chest-wall patients. We performed retrospective qualitative and quantitative analyses of lung-density changes-indicative of asymptomatic fibrosis-for chest-wall patients treated with protons or photons. Our null hypothesis was that, assuming a fixed RBE of 1.1, these changes would be the same for the 2 cohorts, supporting current RBE practice. Our alternative hypothesis was that radiographic abnormalities would be greater for the proton cohort, suggesting an RBE > 1.1.

METHODS AND MATERIALS

We analyzed follow-up computed tomography (CT) scans for 20 proton and photon patients. All were prescribed 50.4 Gy (RBE) in 28 fractions, assuming a fixed RBE of 1.1 for protons and 1 for photons. Deformable registrations enabled us to calculate density changes in the normal lung, specifically (1) median Hounsfield unit (HU) values among posttreatment CT scans and (2) changes in median HU values between pretreatment and posttreatment CT scans, both as a function of grays (RBE). In addition, qualitative abnormality grading was performed by a radiologist.

RESULTS

Proton patients exhibited higher values of HU/Gy (RBE) (endpoint 1) and ΔHU/Gy (RBE) (endpoint 2): P = .049 and P = .00019, respectively, were obtained (likelihood ratio tests of full linear mixed-effects models against models without "modality"). Furthermore, qualitative radiologic scoring indicated a significant difference between the cohorts (Wilcoxon P = .018; median score, 3 of 9 for protons and 1.5 of 9 for photons).

CONCLUSIONS

Our data support the hypothesis that the proton RBE for lung-density changes exceeds 1.1. This RBE elevation could be attributable to (1) the late, normal tissue endpoint that we consider or (2) end-of-range proton linear energy transfer elevation-or a combination of the two. Regardless, our results suggest that variations in proton RBE prove important in vivo as well as in vitro.

An in silico model to demonstrate the effects of Maspin on cancer cell dynamics

Most cancer treatments efficacy depends on tumor metastasis suppression, where tumor suppressor genes play an important role. Maspin (Mammary Serine Protease Inhibitor), an non-inhibitory serpin has been reported as a potential tumor suppressor to influence cell migration, adhesion, proliferation and apoptosis in in vitro and in vivo experiments in last two decades. Lack of computational investigations hinders its ability to go through clinical trials. Previously, we reported first computational model for maspin effects on tumor growth using artificial neural network and cellular automata paradigm with in vitro data support. This paper extends the previous in silico model by encompassing how maspin influences cell migration and the cell-extracellular matrix interaction in subcellular level. A feedforward neural network was used to define each cell behavior (proliferation, quiescence, apoptosis) which followed a cell-cycle algorithm to show the microenvironment impacts over tumor growth. Furthermore, the model concentrates how the in silico experiments results can further confirm the fact that maspin reduces cell migration using specific in vitro data verification method. The data collected from in vitro and in silico experiments formulates an unsupervised learning problem which can be solved by using different clustering algorithms. A density based clustering technique was developed to measure the similarity between two datasets based on the number of links between instances. Our proposed clustering algorithm first finds the nearest neighbors of each instance, and then redefines the similarity between pairs of instances in terms of how many nearest neighbors share the two instances. The number of links between two instances is defined as the number of common neighbors they have. The results showed significant resemblances with in vitro experimental data. The results also offer a new insight into the dynamics of maspin and establish as a metastasis suppressor gene for further molecular research.

Avascular tumour growth dynamics and the constraints of protein binding for drug transportation

The potential for the use of in-silico models of disease in progression monitoring is becoming increasingly recognised, as well as its contribution to the development of complete curative processes. In this paper we report the development of a hybrid cellular automaton model to mimic the growth of avascular tumours, including the infusion of a bioreductive drug to study the effects of protein binding on drug transportation. The growth model is operated within an extracellular tumour microenvironment. An artificial Neural Network based scheme was implemented that modelled the behaviours of each cell (proliferation, quiescence, apoptosis and/or movement) based on the complex heterogeneous microenvironment; consisting of oxygen, glucose, hydrogen ions, inhibitory factors and growth factors. To validate the growth model results, we conducted experiments with multicellular tumour spheroids. These results showed good agreement with the predicted growth dynamics. The outcome of the avascular tumour growth model suggested that tumour microenvironments have a strong impact on cell behaviour. To address the problem of cellular proteins acting as resistive factors preventing efficient drug penetration, a bioreactive drug (tirapazamine) was added to the system. This allowed us to study the drug penetration through multicellular layers of tissue after its binding to cellular proteins. The results of the in vitro model suggested that the proteins reduce the toxicity of the drug, reducing its efficacy for the most severely hypoxic fractions furthest from a functional blood vessel. Finally this research provides a unique comparison of in vitro tumour growth with an intelligent in silico model to measure bioreductive drug availability inside tumour tissue through a set of experiments.

Micromechanical photothermal spectroscopy of trace gases using functionalized polymers

We demonstrate a novel method to spectroscopically detect and identify trace gases. Micromechanical photothermal spectroscopy (MPS) with functionalized sorbent materials provides trace gas spectra in an optical interaction length of only a few micrometers. We use microcavity interferometry to read out displacements as low as 25  fm/√Hz, heating as low as 200  pW/√Hz, and analyte concentrations as low as 65 parts-per-billion for the nerve agent simulant DMMP. MPS integrated with functional materials represents an important new tool in chip-scale optical sensing.

Applying linear systems analysis to dynamic behavior

In this paper we present an abbreviated discussion of the linear systems analysis in the time domain. We then consider the qualitative character of the behavioral dynamics predicted using the linear form of the analysis. The analysis is then extended to a second-order form. We illustrate some relevant new features introduced by the second-order form with a special case example.

Photonic microharp chemical sensors

We describe a new class of micro-opto-mechanical chemical sensors: A photonic microharp chemical sensor is an array of closely spaced microbridges, each differing slightly in length and coated with a different sorbent polymer. They are optically interrogated using microcavity interferometry and photothermal actuation, and are coupled directly to an optical fiber. Simultaneous measurements of the fundamental flexural resonant frequency of each microbridge allow the real-time detection and discrimination of a variety of vapor-phase analytes, including DMMP at concentrations as low as 17 ppb.

Roles and regulation of membrane-associated serine proteases

Pericellular proteolytic activity affects many aspects of cellular behaviour, via mechanisms involving processing of the extracellular matrix, growth factors and receptors. The serine proteases have exquisitely sensitive regulatory mechanisms in this setting, involving both receptor-bound and transmembrane proteases. Receptor-bound proteases are exemplified by the uPA (urokinase plasminogen activator)/uPAR (uPAR receptor) plasminogen activation system. The mechanisms initiating the activity of this proteolytic system on the cell surface, a critical regulatory point, are poorly understood. We have found that the expression of the TTSP (type II transmembrane serine protease) matriptase is highly regulated in leucocytes, and correlates with the presence of active uPA on their surface. Using siRNA (small interfering RNA), we have demonstrated that matriptase specifically activates uPAR-associated pro-uPA. The uPA/uPAR system has been implicated in the activation of the plasminogen-related growth factor HGF (hepatocyte growth factor). However, we find no evidence for this, but instead that HGF can be activated by both matriptase and the related TTSP hepsin in purified systems. Hepsin is of particular interest, as the proteolytic cleavage sequence of HGF is an 'ideal substrate' for hepsin and membrane-associated hepsin activates HGF with high efficiency. Both of these TTSPs can be activated autocatalytically at the cell surface, an unusual mechanism among the serine proteases. Therefore these TTSPs have the capacity to be true upstream initiators of proteolytic activity with subsequent downstream effects on cell behaviour.

Identification of degradome components associated with prostate cancer progression by expression analysis of human prostatic tissues

Extracellular proteases of the matrix metalloproteinase (MMP) and serine protease families participate in many aspects of tumour growth and metastasis. Using quantitative real-time RT–PCR analysis, we have undertaken a comprehensive survey of the expression of these enzymes and of their natural inhibitors in 44 cases of human prostate cancer and 23 benign prostate specimens. We found increased expression of MMP10, 15, 24, 25 and 26, urokinase plasminogen activator-receptor (uPAR) and plasminogen activator inhibitor-1 (PAI1), and the newly characterised serine proteases hepsin and matriptase-1 (MTSP1) in malignant tissue compared to benign prostate tissue. In contrast, there was significantly decreased expression of MMP2 and MMP23, maspin, and the protease inhibitors tissue inhibitor of metalloproteinase 3 (TIMP3), TIMP4 and RECK (reversion-inducing cysteine-rich protein with Kazal motifs) in the cancer specimens. The expression of MMP15 and MMP26 correlated positively with Gleason score, whereas TIMP3, TIMP4 and RECK expression correlated negatively with Gleason score. The cellular localisation of the expression of the deregulated genes was evaluated using primary malignant epithelial and stromal cell cultures derived from radical prostatectomy specimens. MMP10 and 25, hepsin, MTSP1 and maspin showed predominantly epithelial expression, whereas TIMP 3 and 4, RECK, MMP2 and 23, uPAR and PAI1 were produced primarily by stromal cells. These data provide the first comprehensive and quantitative analysis of the expression and localisation of MMPs and their inhibitors in human prostate cancer, leading to the identification of several genes involved in proteolysis as potential prognostic indicators, in particular hepsin, MTSP1, MMP26, PAI1, uPAR, MMP15, TIMP3, TIMP4, maspin and RECK.

Banking of fresh-frozen prostate tissue: methods, validation and use

OBJECTIVE

To describe the establishment, methods, validation and use of a bank of fresh-frozen human prostate tissue.

MATERIALS AND METHODS

On obtaining informed patient consent, protocols were followed for banking prostate tissue from any type of prostatectomy or cystoprostatectomy. A pseudobanking procedure was devised to determine the accuracy of assessing the histopathological status of the banked tissue. RNA was extracted, its quality assessed and used for quantitative real-time reverse transcription-polymerase chain reaction for the serine protease hepsin.

RESULTS

To date prostate tissue from 112 patients has been banked, with pseudobanking in 58. The histopathological assessment showed pseudobanked tissue matched adjacent unbanked tissue in 98% of cases for benign vs malignant diagnoses, and in 92% of carcinomas for the Gleason score. Hepsin expression was significantly higher in malignant than in benign tissues (P < 0.0001).

CONCLUSION

We established a validated method for banking human fresh-frozen prostate tissue and applied it successfully. Hepsin expression can be used to differentiate malignant and benign prostate tissue, and as an indicator of tissue heterogeneity.

Cellular mechanisms regulating non-haemostatic plasmin generation

A variety of proteases have the potential to degrade the extracellular matrix (ECM), thereby influencing the behaviour of cells by removing physical barriers to cell migration, altering cell-ECM interactions or releasing ECM-associated growth factors. The plasminogen activation system of serine proteases is particularly implicated in this pericellular proteolysis and is involved in pathologies ranging from cancer invasion and metastasis to fibroproliferative vascular disorders and neurodegeneration. A central mechanism for regulating plasmin generation is through the binding of the two plasminogen activators to specific cellular receptors: urokinase-type plasminogen activator to the glycolipid-anchored membrane protein uPAR, and tissue plasminogen activator to a type-II transmembrane protein recently identified on vascular smooth muscle cells. These binary complexes interact with membrane-associated plasminogen to form higher order activation complexes that greatly reduce the K(m) for plasminogen activation and, in some cases, protect the proteases from their cognate serpin inhibitors. Various other proteins that are involved in cell adhesion and migration also interact with these complexes, modulating the activity of this efficient and spatially restricted proteolytic system. Recent observations demonstrate that certain forms of the prion protein can stimulate tissue plasminogen activator-catalysed plasminogen activation, which raises the possibility that these proteases may also have a role in the pathogenesis of the transmissible spongiform encephalopathies.

A randomized pilot study of SRL172 (Mycobacterium vaccae) in patients with small cell lung cancer (SCLC) treated with chemotherapy

BACKGROUND

SRL172 is a suspension of heat killed Mycobacterium vaccae, that has been found to be a potent immunological adjuvant when used with autologous cells in animal models. This is a phase II study to test the clinical activity, feasibility and safety of combining SRL172 with chemotherapy to treat patients with small cell lung cancer (SCLC).

METHODS

Patients were randomized to receive chemotherapy with (n=14) or without (n=14) SRL172. The chemotherapy was either platinum-based (MVP, n=10) or anthracycline-based (ACE, n=18). SRL172 was given intradermally on day 0, weeks 4, 8 and then 3-6 monthly.

RESULTS

The treatment arms were well balanced for disease extent (43% with limited stage in each arm). The toxicity of chemotherapy and overall response at 12-15 weeks (57%) was the same for both treatment regimens. Median survival was 8.6 months and 12.9 for patients treated with chemotherapy alone and with the combination respectively (P=0.10). The survival trend was similar for both disease extent and chemotherapy regimen employed in favour of combination chemotherapy with SRL172.

CONCLUSIONS

There is a trend to improved median survival in SCLC with the combination of chemotherapy and SRL172 with no increased toxicity and irrespective of drug regimen. A phase III study examining chemotherapy in combination with SRL172 in SCLC is now underway.

Lobular carcinoma with cytoplasmic granules

We report on a case of invasive lobular carcinoma of the breast with a previously undescribed cytologic feature. Diff-Quik-stained cytologic preparations showed uniform single cells with prominent coarse cytoplasmic granules. Ultrastructurally, the granules showed features suggestive of autophagosomes and/or degenerative mitochondria. The cytologic differential diagnosis included granulocytic sarcoma, metastatic melanoma, extramedullary hematopoiesis, large granulocytic leukemia/lymphoma, and mast-cell tumor. Adjunctive studies were helpful in the diagnosis of carcinoma. Histologic study of the mastectomy specimen showed classic type of invasive lobular carcinoma.

Hyperplasia of mantle/marginal zone B cells with clear cytoplasm in peripheral lymph nodes. A clinicopathologic study of 35 cases

We describe 35 peripheral lymph nodes classified as mantle cell/marginal zone B-cell hyperplasia with clear cells using morphologic and immunologic findings. For the purpose of this study, we obtained clinical follow-up information and performed immunoglobulin gene rearrangement studies on paraffin sections by polymerase chain reaction. Architecturally, the nodes were suggestive of a benign process: no pericapsular infiltration, sinuses readily identified, scattered reactive follicles present, and paracortical nodular hyperplasia present. No monocytoid B cells were present. Focally, small lymphoid cells with round nuclei and clear cytoplasm (clear cells) formed monomorphic nodular, inverse follicular, and/or marginal zone patterns. Flow cytometry and immunohistochemical analysis revealed neither light chain restriction nor an aberrant B-cell phenotype. Immunoglobulin gene rearrangement studies showed a clonal band in 1 of 26 cases in which DNA was amplified. To ascertain the clinical relevance of this positive case, follow-up information was obtained 30 months after the initial biopsy; the 83-year-old woman was alive without treatment but had splenomegaly and bone marrow involvement by marginal zone B-cell lymphoma. The morphologic and immunologic criteria used for diagnosis of mantle cell/marginal zone B-cell hyperplasia with clear cytoplasm are valid; however, to rule out the possibility of occult lymphoma, immunoglobulin gene rearrangement studies and clinical follow-up are necessary.

Thoracolumbar immobilization for trauma patients with torso gunshot wounds: is it necessary?

BACKGROUND

Previous studies have suggested that patients transported by emergency medical services (EMS) following major trauma had a longer injury-to-treatment interval and a higher mortality rate than their non-EMS-transported counterparts.

HYPOTHESIS

There is little actual benefit of thoracolumbar immobilization for patients with torso gunshot wounds (GSW).

DESIGN

Retrospective analysis of prospectively gathered data from the Maryland Institute for Emergency Medical Service Systems State Trauma Registry from July 1, 1995, through June 30, 1998.

SETTINGS

All designated trauma centers in Maryland.

PATIENTS

All patients with torso GSW.

MAIN OUTCOME MEASURES

(1) A patient was considered to have benefited from immobilization if he or she had less than complete neurologic deficits in the presence of an unstable vertebral column, as shown by the need for operative stabilization of the vertebral column; (2) mortality.

RESULTS

There were 1000 patients with torso GSW. Among them, 141 patients (14.1%) had vertebral column and/or spinal cord injuries. Two patients (0.2%) (95% confidence interval, -0.077% to 0.48%) required operative vertebral column stabilization, while 6 others required other spinal operations for decompression and/or foreign body removal. The presence of vertebral column injury was actually associated with lower mortality (7.1% vs 14.8%, P<.02).

CONCLUSIONS

This study suggests that thoracolumbar immobilization is almost never beneficial in patients with torso GSW, and that a higher mortality rate existed among those GSW patients without vertebral column injury vs those with such injuries. The role of formal thoracolumbar immobilization for patients with torso GSW should be reexamined.

Safety of biotechnological products

The safety of biotechnological products used for medicinal products is addressed by EU council directives. The general principles and the regulatory framework for the handling of new drug applications within this areas are described both with respect to benefit/risk evaluation, quality assessment, preclinical safety and efficacy testing.

The toxicology expert: what is required?

In contrast to many traditional professions, toxicologists form a group with very different backgrounds, i.e. they may have been educated to become medical doctors, veterinarians, pharmacists, chemists, biochemists or biologists. Professional competence can be gained in different ways by candidate toxicologists, and according to the European system, their training can be divided into two parts. (i) Theoretical training on several topics such as analytical methods, organ toxicity, mutagenicity, carcinogenicity can be obtained by attending courses organised by the national societies of toxicology. (ii) Spending several years on active experimental work in the fields of modern toxicology (e.g. analytical methods, toxic and genotoxic mechanisms, reproductive toxicity) is necessary to develop the capability to design and carry out experimental studies and to evaluate one's own and other people's research results. Candidate toxicologists should learn to evaluate data with a strictly scientific 'plausibility above numbers' approach.

Cerebro-protective effects of ENA713, a novel acetylcholinesterase inhibitor, in closed head injury in the rat

Focal ischemic brain damage and diffuse brain swelling occur in severe cases of traumatic head injury. Ischemia decreases brain acetylcholine (ACh) levels and head trauma upregulates acetylcholinesterase (AChE) in experimental animal models. The present study determined whether a brain-selective AChE inhibitor, ENA713, given once, up to 2 h after closed head injury (CHI) could reduce the vasogenic edema and accelerate recovery from neurological deficits induced by the injury in rats. ENA713 1-5 mg/kg produced a dose-related inhibition of AChE ranging from 40-85% in the cortex and hippocampus. Doses of 1, 2 and 5 mg/kg, significantly reduced the motor and neurological deficits and speeded recovery, as indicated by measurements made 7 and 14 days after injury. The two larger doses were still effective when injected 1 or 2 h after CHI. The acceleration by ENA713 of recovery of motor function was independent of its reduction in body temperature and was prevented by the simultaneous injection of mecamylamine (2.5 mg/kg), but not by scopolamine (0.2 or 1 mg/kg). Edema in the contused hemisphere (24 h after injury) and disruption of the blood brain barrier (4 h after injury) were significantly reduced (about 50%) by doses of 2 and 5 mg/kg, but not by 1 mg/kg. The data support the hypothesis that ENA713 exerts a neuroprotective effect in brain injury by preventing the decrease in cholinergic activity in cerebral vessels and in neurones.

Mechanism of brain protection by nitroxide radicals in experimental model of closed-head injury

Reactive oxygen-derived species were previously implicated in mediation of post-traumatic brain damage; however, the efficacy of traditional antioxidants in preventing/reversing the damage is sometimes limited. The present work focused on the mechanisms underlying the neuroprotective activity of cell permeable, nontoxic, antioxidants, namely stable nitroxide radicals in an experimental model of rat closed-head injury. Brain damage was induced by the weight-drop method and the clinical status was evaluated according to a neurological severity score at 1 h and 24 h, where the difference between these scores reflects the extent of recovery. The metal chelator deferoxamine as well as three nitroxide derivatives, differing in hydrophilicity and charge, and one hydroxylamine (a reduced nitroxide) facilitated the clinical recovery and decreased the brain edema. The nitroxides, but neither the hydroxylamine nor deferoxamine, protected the integrity of the blood-brain barrier. Superoxide dismutase also improved the clinical recovery but did not affect brain edema or the blood-brain barrier. The results suggest that by switching back and forth between themselves, the nitroxide and hydroxylamine act catalytically as self-replenishing antioxidants, and protect brain tissue by terminating radical-chain reactions, oxidizing deleterious metal ions, and by removal of intracellular superoxide.

The use of TRISS methodology to validate prehospital intubation by urban EMS providers

The purpose of this study was to determine the impact of field orotracheal intubation (OI) by urban emergency medical technician-paramedics (EMT-Ps) on outcome compared with trauma score and injury severity score (TRISS) expectations. The records of all trauma patients intubated by EMT-Ps or hospital personnel were abstracted for OI attempts/ successes, use of neuromuscular blockade (NMB), scene time, discharge neurological status, and hospital survival compared with TRISS. EMT-Ps attempted 43% of all intubations; 81% were successful versus 98% by hospital staff (P < .05). NMB was used by 76% of hospital intubations versus none by EMS (P < .05). Scene time was 10.3 +/- 3.2 minutes versus 11.6 +/- 2.1 for patients intubated by emergency medical services (EMS) and hospital staff (P < .05). Sixty percent of patients intubated by EMS versus 68% by hospital staff had good/moderate discharge neurological status. Survival for patients intubated by EMS versus hospital staff was 11% and 40%, respectively, compared with 2% and 45% expected by TRISS. Field OI by urban EMT-Ps has a favorable impact on survival with good neurological outcome (P < .05).

Cytokine production in the brain following closed head injury: dexanabinol (HU-211) is a novel TNF-alpha inhibitor and an effective neuroprotectant

Traumatic brain injury triggers a cascade of events resulting in delayed edema, necrosis and impaired function. Harmful mediators are accumulating in the brain after injury and recently, the role of cytokines in the pathophysiology of brain injury has been suggested. We have developed an experimental model for closed head injury (CHI), in which edema, blood-brain-barrier disruption, motor and memory dysfunctions have been demonstrated. In this study, spatial and temporal induction of IL-1, IL-6 and TNF-alpha gene mRNA transcription and of TNF-alpha and IL-6 activity in rat brain after CHI are shown. Dexanabinol, HU-211, is a synthetic cannabinoid devoid of cannabimimetic effects; it exhibits pharmacological properties of N-methyl-D-aspartate (NMDA)-receptor antagonist and is an effective cerebroprotectant. We report here that HU-211 is a novel inhibitor of TNF-alpha production at a post-transcriptional stage. HU-211, pentoxyfilline and TNF-binding protein improved the outcome of CHI. We suggest that TNF-alpha is a primary mediator of neurotoxicity after CHI, as inhibition of TNF-alpha is associated with better clinical recovery. TNF-alpha modulating agents, if given within the early time window post-injury, may improve the final neurological outcome in victims of brain trauma.

The utility of two rodent species in carcinogenic risk assessment of pharmaceuticals in Europe

For the past 20-30 years, lifespan carcinogenicity studies for pharmaceuticals have been required to be carried out in two rodent species. Due to scientific progress, the necessity/justification of lifespan studies in two species for the assessment of carcinogenic risk of pharmaceuticals is currently under discussion. A study in one species (either rat or mouse) might suffice. To appraise the need for a study in a second species, a database was compiled of all pharmaceuticals tested for carcinogenicity for which a marketing authorization was applied for in Germany and The Netherlands since 1980. The incidence of treatment-related tumor findings was determined in either rat or mouse or in both. Tumor findings occurred for nearly 50% of all compounds, with the rat being more sensitive than the mouse. Specific attention was given to the question whether tumor findings in mice ever caused the regulatory authorities to refuse registration, to restrict the proposed therapeutic indication of a pharmaceutical, or to apply a cautionary label. It was found that no tumor findings in mice alone ever led to such a regulatory action. In addition, whether mouse studies had been important in interpreting the results of rat studies was determined. A negative mouse study (no tumors found) was rarely used to declare the rat findings irrelevant to humans. A mechanistic explanation was used as a much more important argument in the assessment of tumor findings in rats. In case of transspecies findings, the target organs were the usual ones, such as lung and liver, or the tumors occurred as a result of an exaggerated pharmacodynamic action expected from the pharmacology of the compound. The results of the database thus question the need of maintaining the requirement of rodent carcinogenicity studies in two species.

Inhibition of tumor necrosis factor alpha (TNFalpha) activity in rat brain is associated with cerebroprotection after closed head injury

We recently demonstrated that closed head injury (CHI) in the rat triggers the production of tumor necrosis factor alpha (TNFalpha) in the contused hemisphere. Other investigations have shown that this cytokine plays a role in the inflammatory response following trauma. The present study was designed to determine whether inhibition of TNFalpha production or activity affects the development of cerebral edema as well as neurological dysfunction and hippocampal cell loss after CHI. To this end, we used two pharmacological agents, each acting via a different mechanism: pentoxifylline (PTX), which attenuates the production of TNFalpha, and tumor necrosis factor binding protein (TBP), a physiological inhibitor of TNFalpha activity. Both agents significantly lessened peak edema formation at 24 h and facilitated the recovery of motor function for < or = 4 days postinjury. In addition, TBP attenuated disruption of the blood-brain barrier and protected hippocampal cells. PTX significantly lowered the brain TNFalpha level (by approximately 80%), and TBP completely abolished the activity of recombinant human TNF when they were added at the same time in the in vitro bioassay. We suggest, therefore, that a decrease in TNFalpha level or the inhibition of its activity is accompanied by reduced brain damage.

A novel nonpsychotropic cannabinoid, HU-211, in the treatment of experimental pneumococcal meningitis

Typical features of pneumococcal meningitis have been demonstrated in rats inoculated with Streptococcus pneumoniae. HU-211, a novel noncompetitive N-methyl-D-aspartate antagonist recently demonstrated to inhibit tumor necrosis factor-alpha production under various conditions, improves recovery in some experimental models of brain injury. The present study tested the efficacy of HU-211 in combination with antimicrobial therapy in reducing brain damage in experimental pneumococcal meningitis. S. pneumoniae-infected rats were treated with saline alone, ceftriaxone alone, or with combination of ceftriaxone and HU-211 18 h after inoculation of the bacteria. Brain edema and blood-brain barrier impairment 48 h after infection were significantly (P<.05) reduced suggest that HU-211 when given concomitantly with antibiotics attenuates brain damage in the rat model of pneumococcal meningitis.

Polyamines induce blood-brain barrier disruption and edema formation in the rat

Polyamines (PA) are derived from ornithine by the enzyme ornithine decarboxylase (ODC), which is activated very rapidly as acute and delayed responses to brain ischemia and trauma. Polyamines play a role in the disruption of the blood-brain barrier (BBB) in different pathological states. This study examined the effect of exogenous polyamines, administered intracerebrally (i.c.v.) or intracarotidly on BBB function. Putrescine, spermidine and spermine, given individually, were found to disrupt BBB integrity within 15 min of i.c.v. administration (p = 0.03; p = 0.0013; p = 0.042 vs saline treated rats, respectively). The effect was still evident after 1 h; however, since the saline treated rats also showed increased permeability of Evans blue at this time, there was no statistical difference between polyamines or saline treated rats 1 h post injection. When injected into the carotid artery, rapid increase in BBB permeability was found 1 min after putrescine and spermidine (p < 0.01 vs saline), with a slight decline at 15 min. A slower effect was noticed after spermine administration which reached significance only at 15 min. These results suggest a role for PA as mediators of vasogenic edema formation in the brain soon after brain injuries which induce increased production of these compounds.

Cutting the Cornea With a Waterjet Keratome

BACKGROUND

Waterjet cutting is an advanced technology. It consists of a cutting tool that uses a very thin stream of ultra-high-pressure water forced at high velocity through a very small nozzle, creating a very sharp knife. We report on the first experimental use of waterjet technology to reshape the cornea.

METHODS

The system was used in vitro on 10 bovine eyes, and in vivo on 10 albino rabbit eyes. Using the waterjet keratome (Lipshitz-Bass knife, LBK) lamellar corneal incisions were performed. Histological examinations were performed.

RESULTS

A waterjet stream was found to be capable of incising corneas at relatively low energy levels (4000 PSI). Good surface quality could be obtained, and there was no collateral damage to the remaining portion of the cornea, lens, or retina. In the in vivo experiments, the epithelium healed within 48 hours.

CONCLUSIONS

These preliminary experiments suggest that waterjet technology can be an effective instrument for reshaping the cornea.

The effect of the adrenocortical axis upon recovery from closed head injury

Fragments and analogs of the hormone ACTH were previously shown to have beneficial effect on the outcome of head injury, while elevated levels of corticosterone (CS) exacerbate it. In the present study we investigated the role of the hypothalamo-pituitary-adrenal (HPA) axis in the pathophysiology of closed head injury (CHI). CHI was produced in ether-anesthetized rats by a calibrated weight-drop device. After evaluating the functional status according to a set of criteria, at 1 and 24 h, the rats were sacrificed and cortical tissue was removed to determine its water content. CHI was also produced in rats that underwent surgical procedures to remove their adrenal gland (ADEX) or the pituitary (HypoX), thus altering the levels of their circulating HPA hormones. Given after CHI, to rats with intact HPA axis, ACTH reduced edema and improved recovery. ADEX rats (6 days postsurgery) had 10-fold higher levels of plasma ACTH. ADEX rats subjected to CHI showed improved functional outcome (p = 0.008) and reduced edema (p = 0.02). We then produced CHI in three groups of rats: HypoX (15 days postsurgery), HypoX treated with ACTH, and controls. In HypoX rats, CHI resulted in increased mortality (35% vs 0) and edema in the surviving rats, and a slower recovery, as compared with the control. Mortality was prevented, edema slightly reduced, and recovery significantly improved after administration of 1-24-ACTH to HypoX rats with CHI. Our results suggest that ACTH has a cerebroprotective effect on the outcome of CHI.

Electrophysiological properties of human coronary endothelial cells

The electrophysiological properties of human coronary endothelial cells (HCEC) of macro- and microvascular origin were studied using the whole-cell configuration of the patch-clamp technique. The membrane potential of confluent HCEC (-41.9 +/- 3.9 mV (mean +/- SEM, n = 32) for macro- and -33.6 +/- 2.6 mV (n = 64) for microvascular cells, respectively) was less negative than the K+ equilibrium potential. Inward currents of isolated cells at potentials below the K+ equilibrium potential were blocked by external Ba2+ (1 mM), inactivated due to time- and voltage-dependent block caused by external Na+, and their amplitudes were enhanced by increasing extracellular [K+]; these currents were identified as inwardly rectifying K+ currents. Some isolated cells displayed outwardly directed K+ currents which were abolished after replacement of Cs+ for K+ on both sides of the membrane. Voltage-dependent Ca2+ currents could not be observed in isolated HCEC. Hyperpolarizations induced by vasoactive agonists have been observed in some endothelial cells from different species. In contrast, extracellularly applied ATP (adenosine-5'-triphosphate) and ADP (adenosine-5'-diphosphate) at micromolar concentrations depolarized confluent HCEC, whereas adenosine had no effect on resting potentials (RP), indicating that the nucleotide-induced depolarizations were mediated via P2- purinoceptors. These depolarizations occurred even after replacement of N-methyl-D-glucamine for extracellular Na+, indicating that Ca(2+)-influx was involved. There were no marked differences in the electrophysiological properties between cells of macro and microvascular origin.

Long-term effect of HU-211, a novel non-competitive NMDA antagonist, on motor and memory functions after closed head injury in the rat

HU-211 is a synthetic, non-psychotropic cannabinoid which acts as a non-competitive NMDA antagonist and antioxidant. We studied the drug's therapeutic window as well as its long-term effect on cognitive and motor functions in a model of closed head injury (CHI) in the rat. A weight-drop device was used to induce CHI in either anesthetized male rats. HU-211 (5 mg/kg) was administered i.v. to the experimental groups. For the therapeutic window study, drug was injected at 4 or 6 h after CHI. Edema (water content) and clinical status (neurological severity score, NSS) were evaluated at 24 h. Reduction of edema was slight, whereas improvement of NSS was significant when the drug was administered at 4 or 6 h (P = 0.0023 and 0.059, respectively). To determine the drug's long-term effect, it was administered 1 h after CHI and additional doses were later given. NSS was evaluated for a period of 30 d. A single dose of HU-211 given 1 h post-CHI improved the clinical outcome during the 30 d period (P < 0.01). Repetitive doses of HU-211 injected during the post traumatic period had similar effects. Cognitive functions were evaluated in the Morris water maze, with rats trained either before or after CHI. CHI resulted in a highly significant impairment of these abilities, whereas HU-211 treatment 1 h after CHI improved performance. Our results indicate that HU-211 is a potent cerebroprotective agent, with a therapeutic window of about 4 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Closed head injury triggers early production of TNF alpha and IL-6 by brain tissue

In a model of closed head injury (CHI) in the rat we have shown the activation of phospholipase A2 and the production of eicosanoids after injury: at 15 min, mainly 5-hydroxyeicosatetraenoic acid (5-HETE), and at 24 h, mainly prostaglandin E2. The present study was designed to test whether CHI can also trigger the production of cytokines in the brain. CHI was induced in ether-anesthesized rats by a weight-drop device falling over the exposed skull covering the left hemisphere, 1-2 mm lateral to the midline in the midcoronal plane. In the posttraumatic period (1-24 h), the rats were decapitated, cortical tissue from the injured zone of the contused and contralateral hemispheres was removed and sonicated, and cytokine activity was assessed. Whereas no tumor necrosis factor alpha (TNF alpha) activity was found in normal brain tissue, it was detectable in the contused hemisphere (approximately of 72 +/- 50 pg/mg protein) as early as 1 h post-CHI. TNF alpha levels increased at 2 h, peaked at 4 h, (approximately of 609 +/- 540 pg/mg protein), and declined thereafter. At parallel intervals, only low levels of TNF alpha were detected in the contralateral hemisphere. In normal brain, interleukin-6 (IL-6) was nondetectable. Following CHI, high levels of IL-6 were present, although their accumulation lagged behind that of TNF alpha by 2-4 h, peaking at 8 h (62 +/- 31 ng/mg protein). We suggest that the rapid production of TNF alpha and IL-6 following CHI is a local inflammatory response of brain tissue to primary insult.

Are newer scientific concepts in regulatory toxicology used timely and appropriately?

Laws regulating toxicology (e.g. toxic thresholds allowed, poison classes or definition of necessary preclinical testing) might improve health and save lives. Scientific facts will always serve as a mandatory base for political decision-making, but there will also be additional influences (perception and acceptance of risks, possible benefits, economic considerations etc.). These latter factors may vary considerably from one society to another. The Delaney clause prohibited the marketing of any product which was found to be carcinogenic in animals. Due to their benefits, exceptions were made for drugs. In other countries, too, other chemicals could be an exception due to a different perception of the risk or different scientific evaluation. Clear cases of major events always trigger changes in legislation. When in 1937 a newly-marketed sulfanilamide elixir led to severe kidney damage and 70 deaths, the FDA quickly endorsed the propositions of the investigation team set up by the American Medical Association: animal testing in two species with histopathologic examination before a marketing authorization could be granted became mandatory. A similarly rapid reaction followed in Europe when it was detected that Thalidomide was responsible for malformations in the offspring of mothers who had taken the drug in early pregnancy. When the effects are more difficult to link to a chemical, there may be time delays in regulatory actions. However, a sophisticated evaluation system was introduced for better monitoring of drug and chemical hazards. Some examples will be given in order to discuss the difficulties of timely and appropriate use of scientific findings.

Current guidelines for the preclinical safety assessment of therapeutic proteins

Guidelines concerning the preclinical safety assessment of therapeutic proteins are available, e.g. in the European Community (EC Notes for Guidance). Unlike rather rigidly prescribing test systems such as those known for chemical substances, it is agreed that for biotechnologically-produced products, testing may be quite different. Those guidelines which allow for a true case-by-case development have been considered the best; however, regulatory authorities are expected to disagree ex post with the approach chosen earlier. To allow for a scientific rationale, which includes the freedom to deviate from the expected norm, guidance must include an offer for discussion of requirements. This combination of recommendations (not requirements) with optional discussions has been the European approach. Although the American approach is known to be somewhat more case-by-case oriented, and the Japanese approach is known to be somewhat more strict, the outcome of drug development, i.e. the application of guidance, in the three regions has been strikingly similar. This underlines the importance of a pharmaceutical manufacturer and his ability to interpret the rules in the light of the product to be developed.

A proposed approach to regulating contaminated soil: identify safe concentrations for seven of the most frequently encountered exposure scenarios

Since 1980, more than 10,000 sites in the United States have been shown to contain soil which has elevated concentrations of various xenobiotics. Since that time, guidelines for deciding whether the level of contamination is worthy of concern have been proposed or promulgated by dozens of local, state, and federal regulatory agencies. Unfortunately, there has been little consistency in the guidelines suggested for each soil contaminant. For example, (a) the basis or rationale for some of the cleanup levels is unclear, (b) approaches to setting cleanup levels vary between states and agencies, (c) cleanup objectives often vary among agencies within the same state, and (d) the cleanup levels are usually set in a scientifically haphazard manner. This paper proposes that the most cost-effective and efficient way to quickly regulate contaminated soil is to establish "safe" concentrations for each chemical for the seven most common exposure scenarios. These exposure scenarios include (1) residential, (2) industrial, (3) agricultural, (4) recreational, (5) groundwater, (6) wildlife and aquatic species, and (7) runoff/erosion of particulates to waterways. The scientific approach and rationale for calculating the cleanup criteria are illustrated by evaluating dioxin and benzene, toluene, and xylene (BTX). The methods suggested here indicate that levels of dioxin of 25 and 50 ppb in residential and industrial soils, respectively, should be acceptable. The predominant concern for the agricultural and recreational scenarios is the runoff of particulates to waterways. For BTX, benzene will dictate the degree of cleanup and the primary hazard at most residential sites will be the inhalation of vapors. Benzene concentrations of 2.5, 14, and 250 ppm should be acceptable for residential, industrial, and recreational soils, respectively. Depending on the depth to groundwater and aquifer use, protection of groundwater may be the driving concern for establishing BTX cleanup levels and must be determined using site-specific factors.

The uninsured and the debate over the repeal of the Massachusetts universal health care law

OBJECTIVES

The debate in Massachusetts over the repeal of the first state-based "pay or play" universal health plan is discussed using data from a survey of 1066 Massachusetts households. The survey attempted to measure the problems of the uninsured, to estimate the likelihood that they would buy insurance if offered, and to calculate the proportion of the uninsured who would be covered under an employer mandate.

DESIGN

A survey conducted in person and by telephone in 1066 households, with an oversample of uninsured households, using stratification, clustering, disproportionate sampling, and poststatistical weighting.

PARTICIPANTS

Adults aged 18 years and older who were knowledgeable about the insurance status of persons in their household.

MAIN OUTCOME MEASURES

Insurance status, employment status, access to and use of health services, and willingness to purchase health insurance.

RESULTS

First, the present system of hospital-based uncompensated care in Massachusetts is inadequate by itself to meet the needs of uninsured residents. Uninsured persons are less likely than insured ones to seek medical care for chronic health problems and serious symptoms requiring evaluation. Second, 83% of uninsured families and 24% of uninsured individual respondents would purchase one of several insurance options with 30% of the cost subsidized. Last, the employer mandate provisions of the legislation would cover 43% of the uninsured in Massachusetts.

CONCLUSION

In the current economic climate, the political viability of the universal health care plan and similar national initiatives is uncertain given the intractable conflict between perceptions of the financial stability of small businesses that do not offer insurance and the health care needs of uninsured individuals.

Considerations regarding the development of individual nonclinical test strategies in the European Community

The wish of pharmaceutical companies to be given the most binding possible preclinical test programmes for a new product, and the tendency of authorities to regulate to a great extent the preclinical testing of new drugs (especially at a multinational level), has led to differing requirements and practices in preclinical testing in different areas of the world. These differing requirements and practices have of necessity brought in their wake varying scientific criteria, with particular regard to animal protection, ethical standards, as well as imposing apparently unjustified extra financial costs. In order to improve this situation, the development of drug-specific preclinical test strategies is proposed in a drafted E. C. Note for Guidance, which incorporates already existing drug-testing guidelines and method recommendations. This draft Note for Guidance points to general methods of analysing problems and reaching decisions and thus appears to be worthy of recommendation as practical and desirable. It requires the co-operation of drug producers and supervisory authorities at a high scientific and ethical level. With regard to the state-of-the art and the socio-political background, the fulfillment of these requirements would appear not only to be appropriate but also imperative. To put them into practice would contribute enormously to the improvement of drug development and to de-emotionalization of the public debate. Therefore, comments on these draft guidelines from societies and associations are urgently sought and awaited with keen interest.

Basic requirements for the toxicity testing of antimicrobial agents

The regulations in different countries on the toxicological testing of antimicrobial agents are similar and harmonized on an international basis. Existing requirements cover both the standard investigations performed with any other new class of therapeutic drug and investigations necessary due to the specific features of anti-infective agents. Such features are the therapeutic target (the microorganisms), the need to provide adequate treatment of patients even during clinical trials, and the potential of the drug to induce certain adverse reactions. The combination of toxicity tests used will be determined by the drug, its class and current knowledge.

Stereological study of the developing distal femoral growth plate

The distal femoral growth plate has a uniquely convoluted structure comprised of four mammillate processes. Factors contributing to the development of these processes and overall plate geometry were explored using three-dimensional image analysis of the canine distal femoral epiphysis. The growth plate at birth remains relatively flat until ossification of the epiphysis begins at 1 week of age. Epiphyseal ossification proceeds eccentrically, projecting in the medial-lateral and anterior-posterior directions. Growth plate activity indexed by [3H]thymidine labeling and plate thickness revealed regional differences in cell proliferation. This was measured as a decreased labeling index and thinning of the growth plate in areas capped by the ossifying epiphysis. The eccentric ossification pattern and associated variations in growth plate activity result in definition of an "intraphyseal" groove and medial-lateral oriented sulcus. The groove and sulcus bisect the plate into four quadrants, giving rise to a convoluted structure composed of four areas of plate elevations termed mammillary processes (MP). By 5 weeks, the pattern of ossification results in greater development of the MP in the anterior-medial quadrant and in decreasing order, in the posterior-medial, anterior, and posterior-lateral quadrants. By 10 weeks, a uniform rate of cell proliferation was observed coincident with completion of ossification of the epiphysis. The data suggest that localized variations in growth plate proliferation are associated with ossification of the epiphysis.(ABSTRACT TRUNCATED AT 250 WORDS)