Trace elemental imaging of coralline hydroxyapatite by laser-ablation inductively coupled plasma-mass spectroscopy

The determination of trace element concentrations, as well as their distribution in different biomaterials aimed for clinical applications, is a challenging task in both the areas of biological and materials research. In this research, LA-ICP-MS was employed for image mapping of the trace element distribution in a hydrothermally converted coralline hydroxyapatite material aimed for tissue-scaffolding applications. Quantification using synthetic matrix-matched standards was successfully applied for the determination and distribution of elements of interest, Sr and Mg, that influences the mechanical and biological properties of hydroxyapatite-based bone graft materials. The results showed that the instrument can successfully analyse trace elements and a relatively good image can be produced that identifies their distribution. The LA-ICP-MS method can provide an easy and effective tool, in the field of biomaterials with respect to distribution of trace elements, to better understand tissue-implant interactions, and will open up a new window for in vitro and in vivo analysis and imaging of different tissues and structures.

Strontium- and magnesium-enriched biomimetic β-TCP macrospheres with potential for bone tissue morphogenesis

During the last two decades, biogenic mineral ions have become important additives in treatments for bone regeneration and repair. Prominent among these is strontium, which is a potent suppressor of osteoclast bone resorption. Another is magnesium, which has a key influence in mineralization processes. The shells of benthic foraminiferans, hydrothermally converted into β-TCP, have been shown to effectively release a number of bone-promoting drugs at clinically relevant levels. In this study we characterized the effects of converted foraminiferan calcium dissolution and the concomitant release profile of intrinsic strontium and magnesium. We tested the effects of strontium- and magnesium-enriched macrospheres on human osteoblast (SaOS-2) and monocytoid (U937) cell lines, which can be induced to express equivalent phagocytic activities to osteoclasts. On dissolution in a biomimetic physiological solution, the macrospheres released biologically significant quantities of calcium and phosphate ions in the first 18 days. At 3 days, during which biogenic mineral ions are released, the number of U937 osteoclast-like monocyte cells decreased, while 4 days later the osteoblast cell number increased. These results show that strontium and magnesium naturally enriched macrospheres are capable of altering the metabolic activities of the cells regulating bone homeostasis. These unique macrospheres are natural origin bone void filler particles that resorb, and release physiologically significant levels of incorporated strontium, magnesium and calcium, which together make a uniquely multifunctional in situ remedy for bone regeneration and repair and the treatment of bone-wasting diseases.

Strategies to defeat ketamine-induced neonatal brain injury

Studies using animal models have shown that general anesthetics such as ketamine trigger widespread and robust apoptosis in the infant rodent brain. Recent clinical evidence suggests that the use of general anesthetics on young children (at ages equivalent to those used in rodent studies) can promote learning deficits as they mature. Thus, there is a growing need to develop strategies to prevent this injury. In this study, we describe a number of independent approaches to address therapeutic intervention. Postnatal day 7 (P7) rats were injected with vehicle (sterile PBS) or the NMDAR antagonist ketamine (20 mg/kg). After 8 h, we prepared brains for immunohistochemical detection of the pro-apoptotic enzyme activated caspase-3 (AC3). Focusing on the somatosensory cortex, AC3-positive cells were then counted in a non-biased stereological manner. We found AC3 levels were markedly increased in ketamine-treated animals. In one study, microarray analysis of the somatosensory cortex from ketamine-treated P7 pups revealed that expression of activity dependent neuroprotective protein (ADNP) was enhanced. Thus, we injected P7 animals with the ADNP peptide fragment NAPVSIPQ (NAP) 15 min before ketamine administration and found we could dose-dependently reverse the injury. In separate studies, pretreatment of P6 animals with 20 mg/kg vitamin D(3) or a nontoxic dose of ketamine (5 mg/kg) also prevented ketamine-induced apoptosis at P7. In contrast, pretreatment of P7 animals with aspirin (30 mg/kg) 15 min before ketamine administration actually increased AC3 counts in some regions. These data show that a number of unique approaches can be taken to address anesthesia-induced neurotoxicity in the infant brain, thus providing MDs with a variety of alternative strategies that enhance therapeutic flexibility.

Enhanced survival of dopaminergic neuronal transplants in hemiparkinsonian rats by the p53 inactivator PFT-α

A key limiting factor impacting the success of cell transplantation for Parkinson's disease is the survival of the grafted cells, which are often short lived. The focus of this study was to examine a novel strategy to optimize the survival of exogenous fetal ventromesencephalic (VM) grafts by treatment with the p53 inhibitor, pifithrin-α (PFT-α), to improve the biological outcome of parkinsonian animals. Adult male Sprague-Dawley rats were given 6-hydroxydopamine into the left medial forebrain bundle to induce a hemiparkinsonian state. At 7 weeks after lesioning, animals were grafted with fetal VM or cortical tissue into the lesioned striatum and, thereafter, received daily PFT-α or vehicle injections for 5 days. Apomorphine-induced rotational behavior was examined at 2, 6, 9, and 12 weeks after grafting. Analysis of TUNEL or tyrosine hydroxylase (TH) immunostaining was undertaken at 5 days or 4 months after grafting. The transplantation of fetal VM tissue into the lesioned striatum reduced rotational behavior. A further reduction in rotation was apparent in animals receiving PFT-α and VM transplants. By contrast, no significant reduction in rotation was evident in animals receiving cortical grafts or cortical grafts + PFT-α. PFT-α treatment reduced TUNEL labeling and increased TH(+) cell and fiber density in the VM transplants. In conclusion, our data indicate that early postgrafting treatment with PFT-α enhances the survival of dopamine cell transplants and augments behavioral recovery in parkinsonian animals.

Descending necrotizing mediastinitis as a complication of odontogenic infection

Descending necrotizing mediastinitis (DNM) is a serious, life threatening complication that can occur from a common odontogenic infection. Even with advancements in antibiotics, diagnostic imaging, and surgical management, the mortality rate remains between 20 and 40%. It is imperative that the practitioner taking care of patients with odontogenic infections be sensitized to this potentially fatal complication. We report the successful management of a case of mediastinitis complicating an odontogenic infection in a 39-year-old male.

Histogranin reduced brain injury after transient focal ischemia in rats

Excitatory amino acids (EAAs) play an important role during ischemic brain injury. In this study we examined the protective effect of histogranin (HN), an endogenous peptide that antagonizes excitatory amino acids-mediated activity noncompetitively, in an animal model of cerebral ischemia. Adult rats were anesthetized with chloral hydrate. Histogranin was given intracerebroventricularly before a 60-min middle cerebral artery occlusion (MCAo). Animals were examined for their locomotor activity 2 days after MCAo. Histogranin significantly increased locomotor activity in the stroke rats. Histogranin pretreatment reduced the volume of cerebral infarction and the caspase-3 immunoreactivity in the stroke animals. Taken together, our data suggest that histogranin is protective against ischemic brain injury. The protective effect may involve anti-apoptotic mechanisms.

Neurotrophic effects of bone morphogenetic protein-7 in a rat model of Parkinson's disease

Previous studies have demonstrated that pretreatment with bone morphogenetic protein-7 (BMP7) reduces ischemic neuronal injury in vivo. Moreover, exogenous application of BMP7 increases both the number of tyrosine hydroxylase (+) cells and dopamine (DA) uptake in rat mesencephalic cell cultures. The purpose of this study was to investigate the in vivo effects of BMP7 on 6-hydroxydopamine (6-OHDA) induced lesioning of midbrain DA neurons. Adult Fischer 344 rats were anesthetized and injected with BMP7 or vehicle into the left substantia nigra, followed by local administration of 9 microg of 6-OHDA into the left medial forebrain bundle. The lesioned animals that received BMP7 pretreatment, as compared to vehicle/6-OHDA controls, had a significant reduction in methamphetamine-induced rotation 1 month after the surgery. BMP7-pretreatment partially preserved KCl-induced dopamine release in the lesioned striatum and significantly increased TH immunoreactivity in the lesioned nigra and striatum. In summary, our data suggest that BMP7 has neuroprotective and/or neuroreparative effects against 6-OHDA lesioning of the nigrostriatal DA pathway in an animal model of Parkinson's disease (PD).

Bone morphogenetic proteins are involved in fetal kidney tissue transplantation-induced neuroprotection in stroke rats

Both bone morphogenetic proteins (BMPs) and glial cell line-derived neurotrophic factor (GDNF) reduce ischemia-induced cerebral injury in rats. Intracerebral transplantation of fetal kidney tissue, which normally expresses BMPs and GDNF during development, reduces ischemic injury in cerebral cortex. In this study, we tested the hypothesis that BMP is involved in this neuroprotective response. Fetal kidney tissue was cut into small pieces and transplanted into cortical areas adjacent to the right middle cerebral artery (MCA) in adult rats. In situ hybridization of brain indicated that these fetal kidney transplants contained high levels of BMP-7 mRNA three days after grafting. Immunohistochemical analysis of grafted brain showed co-localization of BMP-7 and PAX-2 immunoreactivity in the graft, suggesting that these transplants contained BMP protein. Some animals were grafted with fetal kidney tissue after intraventricular administration (ICV) of the BMP antagonist noggin (1 micro g) or after vehicle, followed by MCA ligation for 60 min. Animals receiving fetal kidney tissue transplantation developed significantly less body asymmetry, as compared to stroke animals that either did not receive transplantation or received fetal kidney grafts and noggin pretreatment. Analysis of these brains after triphenyltetrazolium chloride staining showed that fetal kidney tissue transplantation reduced the volume of infarction in the cerebral cortex. Noggin pretreatment reduced the protection induced by fetal kidney grafting, although noggin itself did not cause increase in cerebral infarction. Eight hours after ischemia, brain homogenates were obtained from grafted and control animals to assay caspase-3 enzymatic activity. This analysis demonstrated that fetal kidney grafts significantly reduced ischemia-induced caspase-3 activity. Reduction of caspase-3 activity could also be antagonized by noggin pretreatment. In conclusion, our data suggest that fetal kidney transplantation reduces ischemia/reperfusion-induced cortical infarction and behavioral deficits in adult rats, which are, at least partially, mediated through the effect of BMPs from the transplants.

Filamin A, the Arp2/3 complex, and the morphology and function of cortical actin filaments in human melanoma cells

The Arp2/3 complex and filamin A (FLNa) branch actin filaments. To define the role of these actin-binding proteins in cellular actin architecture, we compared the morphology of FLNa-deficient human melanoma (M2) cells and three stable derivatives of these cells expressing normal FLNa concentrations. All the cell lines contain similar amounts of the Arp2/3 complex. Serum addition causes serum-starved M2 cells to extend flat protrusions transiently; thereafter, the protrusions turn into spherical blebs and the cells do not crawl. The short-lived lamellae of M2 cells contain a dense mat of long actin filaments in contrast to a more three-dimensional orthogonal network of shorter actin filaments in lamellae of identically treated FLNa-expressing cells capable of translational locomotion. FLNa-specific antibodies localize throughout the leading lamellae of these cells at junctions between orthogonally intersecting actin filaments. Arp2/3 complex-specific antibodies stain diffusely and label a few, although not the same, actin filament overlap sites as FLNa antibody. We conclude that FLNa is essential in cells that express it for stabilizing orthogonal actin networks suitable for locomotion. Contrary to some proposals, Arp2/3 complex-mediated branching of actin alone is insufficient for establishing an orthogonal actin organization or maintaining mechanical stability at the leading edge.

Formation of chloropyromorphite in a lead-contaminated soil amended with hydroxyapatite

Conversion of soil Pb to pyromorphite [Pb5(PO4)3Cl] was evaluated by reacting a Pb contaminated soil collected adjacent to a historical smelter with hydroxyapatite [Ca5(PO4)3OH]. In a dialysis experiment where the soil and hydroxyapatite solids were placed in separate dialysis bags suspended in 0.01 M NaNO3 solution a crystalline precipitate, identified as chloropyromorphite, formed on the dialysis membrane containing the soil. The aqueous composition of the solution indicated that dissolution of solid-phase soil Pb was the rate-limiting step for pyromorphite formation. Addition of hydroxyapatite to the soil caused a decrease in each of the first four fractions of sequential extractable Pb and a 35% increase in the recalcitrant extraction residue. After a 240-d incubation at field-moisture content there was a further increase in the recalcitrant extraction residue fraction of the hydroxyapatite-amended soil to 45% of the total soil Pb. The increase in the extraction residue fraction in the hydroxyapatite amended 0-d incubated soil as compared to the control soil illustrates that the chemical extraction procedure itself caused changes in extractability. Thus, the chemical extraction procedure cannot easily be utilized to confirm changes occurring in amended soils. The further increase after the 240-d incubation implies that the reaction also occurs in the soil during incubation. Extended X-ray absorption fine structure (EXAFS) spectroscopy indicated that after the 240-d incubation the hydroxyapatite treatment caused a change in the average, local molecular bonding environment of soil Pb. Low-temperature EXAFS spectra (chi data and radial structure functions--RSFs) showed a high degree of similarity between the chemical extraction residue and synthetic pyromorphite, providing additional evidence that the change of soil Pb to pyromorphite is possible by simple amendments of hydroxyapatite to soil.

Methamphetamine causes widespread apoptosis in the mouse brain: evidence from using an improved TUNEL histochemical method

Terminal deoxynucleotidyl transferase (TdT)-mediated dNTP nick end labeling (TUNEL) histochemistry is a sensitive method to expose DNA strand breaks in apoptotic cells, but it is difficult to conduct on slide-mounted sections. By using a 80 degrees C/0.5% Triton X-100 pretreatment, we have developed a TUNEL histochemical approach with high specificity and sensitivity using sections from ischemic rat brains. Thereafter, methamphetamine (METH)-induced neuronal death was investigated in mice brains. The results showed that a single injection of 40 mg/kg METH caused neuronal death in several brain areas including the striatum, cortex (frontal, parietal, and piriform), indusium griseum, medial habenular nucleus, and hippocampus. These results further confirmed the presence of METH-induced deleterious effects in nondopaminergic neurons. The significance of these findings is also discussed.

Bone morphogenetic protein-6 reduces ischemia-induced brain damage in rats

BACKGROUND AND PURPOSE

Bone morphogenetic protein-6 (BMP6) and its receptors are expressed in adult and fetal brain. Receptors for BMP6 are upregulated in adult brain after injury, leading to the suggestion that BMP6 is involved in the physiological response to neuronal injury. The purpose of this study was to determine whether there was a neuroprotective effect of BMP6 in vivo and in vitro.

METHODS

Lactate dehydrogenase and microtubule-associated protein-2 (MAP-2) activities were used to determine the protective effect of BMP6 against H(2)O(2) in primary cortical cultures. The neuroprotective effects of BMP6 were also studied in chloral hydrate-anesthetized rats. BMP6 or vehicle was injected into right cerebral cortex before transient right middle cerebral artery (MCA) ligation. Animals were killed for triphenyl-tetrazolium chloride staining, caspase-3 immunoreactivity and enzymatic assays, and TUNEL assay. A subgroup of animals were used for locomotor behavioral assays.

RESULTS

Application of H(2)O(2) increased lactate dehydrogenase activity and decreased the density of MAP-2(+) neurons in culture. Both responses were attenuated by BMP6 pretreatment. Complementary in vivo studies showed that pretreatment with BMP6 increased motor performance and generated less cerebral infarction induced by MCA ligation/reperfusion in rats. Pretreatment with BMP6 did not alter cerebral blood flow or physiological parameters. There was decreased ischemia-induced caspase-3 immunoreactivity, caspase-3 enzymatic activity, and density of TUNEL-positive cells in ischemic cortex in BMP6-treated animals.

CONCLUSIONS

BMP6 reduces ischemia/reperfusion injury, perhaps by attenuating molecular events underlying apoptosis.

Acute effects of growth hormone on metabolism of pancreatic hormones, glucose and ketone bodies

Controversy exists as to whether acute administration of growth hormone has insulin-like effects. In conscious dogs, acute effects on plasma flows, plasma glucose, hepatic glucose output, free fatty acids, ketone bodies, insulin, and glucagon were determined following intravenous injection of 1 mg of growth hormone extracted from the canine pituitary gland. The following results were obtained: (1) Plasma flows in the portal vein, hepatic artery and hepatic vein were significantly increased 20 min after growth hormone administration. (2) By 40 min after growth hormone, the glucose concentration in these three vessels was significantly increased. (3) Hepatic glucose output was significantly increased 60 min after growth hormone administration. (4) Free fatty acids levels were significantly but transiently increased at 20 min, while ketone body concentrations were elevated at 120-180 min. (5) The insulin levels in the three vessels demonstrated a biphasic response. In the portal vein, they were significantly higher 20 min after growth hormone and again at 150-180 min. Glucagon concentrations were increased in all three vessels by 20 min and remained elevated for the remainder of the experiment. These results do not support an acute insulin-like action of growth hormone in normal dogs.

Oral delivery of biologically active parathyroid hormone

PURPOSE

Parathyroid hormone (PTH), the only drug known to stimulate bone formation. is a peptide therapeutic indicated in the treatment of osteoporosis. Unfortunately, PTH is only effective when dosed by injection because it has no oral bioavailability. Herein we report the oral absorption of PTH in rats and monkeys facilitated by the novel delivery agent, N-[8-(2-hydroxy-4-methoxy)bensoyl]amino caprylic acid (4-MOAC).

METHODS

4-MOAC was selected from a group of 100 delivery agents based on in vitro chromotography studies and in vivo screening studies in rats. The PTH/4-MOAC combination was then tested in monkeys. The interaction of 4-MOAC and PTH was evaluated by nuclear magnetic resonance (NMR) spectroscopy.

RESULTS

Monkeys were administered an aqueous solution containing 4-MOAC and PTH and mean peak serum PTH concentrations of about 3000 pg/mL were obtained. The relative bioavailability of oral PTH was 2.1% relative to subcutaneous administration. The biological activity of the orally-delivered PTH was further evaluated in a rat model of osteoporosis. These studies showed that the bone formed following oral PTH/4-MOAC administration was comparable to that formed following PTH injections. The 4-MOAC mediated absorption of PTH is hypothesized to be the result of a noncovalent interaction between 4-MOAC and PTH. The preliminary evaluation of this interaction by NMR is described.

CONCLUSIONS

4-MOAC facilitates the absorption of PTH following oral administration to both rats and monkeys. The orally-absorbed PTH is biologically active as demonstrated in a rat model of osteoporosis.

Specific secondary structures in the capsid-coding region of giardiavirus transcript are required for its translation in Giardia lamblia

Enhanced translation of giardiavirus (GLV)-luciferase chimeric mRNA in Giardia lamblia requires the presence of the initial 264 nucleotides of the viral capsid-coding region. A 13 nt downstream box (DB) sequence within this region, complementary to a 15 nt sequence near the 3' end of G. lamblia 16 S-like ribosomal RNA (rRNA), was found to be essential for the enhanced translation. However, DB is located 64-78 nt downstream of the initiation codon, whereas an exponential increase of translation efficiency depends on a further increment of the coding region from nucleotides 111 to 264. Thus, there could be additional structural requirements for translation enhancement in the region downstream from DB. Four major stem-loop structures, designated I to IV, were identified in the MFOLD-predicted secondary structure of the 264 nt capsid-coding region with an estimated minimum free energy (DeltaG degrees ) of -77.16 kcal x mol(-1). Our chemical probing analysis of the free 264 nt RNA molecule in solution supports the predicted presence of stem-loops I, II and III, but casts doubts on stem-loop IV. It suggests, instead, the presence of a stem-loop IVA at a nearby location in the molecule. Site-directed mutagenesis designed to disrupt stem-loop structures I, II, III or IVA resulted in drastic reduction of translation efficiency, which was restored by compensatory sequence changes to regenerate individual stem-loop structures. Mutations disrupting the originally designated stem-loop IV did not exert any detectable effect on translation. However, alterations of the sequence UCUCC between nucleotides 216 and 220 in the flexible loop region of the revised secondary structure led to a precipitous drop in translation. Another stem-loop predicted by MFOLD that consists of a major portion of the DB sequence was examined by chemical probing but found little experimental support. Changes of the DB sequence without affecting the postulated stem structure led to drastic losses of translation efficiency. Thus, a simple structural basis for the enhanced translation could be that stem-loops I, II, III and IVA and the UCUCC sequence may facilitate the interaction between DB and the anti-DB in 16 S-like rRNA in initiating translation of GLV mRNA in G. lamblia.

Chronic methamphetamine exposure decreases high affinity uptake function in norepinephrine afferents in the cerebellar cortex: an electrophysiological and electrochemical study

It has been reported that chronic methamphetamine (MA) treatment decreases monoamine release in different brain regions. However, the clearance of norepinephrine (NE) after chronic MA intake is not clear. In the present study, we administered MA to Sprague-Dawley rats for 1 month. The animals were later anesthetized with urethane for electrophysiological recording. Previous studies have indicated that gamma-aminobutyric acid (GABA)-induced electrophysiological responses are enhanced by norepinephrine (NE) acting via postsynaptic beta-adrenergic receptors. We found that local application of the NE high affinity uptake inhibitor desmethylimipramine (DMI) significantly potentiated GABA-induced electrophysiological depressions in cerebellar Purkinje neurons in control rats. In contrast, DMI did not augment GABA responses in rats chronically treated with MA for 1 month, or in rats withdrawn from MA for 7-14 days after a 1-month MA treatment. To further examine if DMI-induced GABA modulation is altered by post- or pre-synaptic mechanisms in chronic MA-treated rats, we examined the electrophysiological interaction of GABA and isoproterenol (ISO), a postsynaptic beta-adrenergic receptor agonist, in Purkinje neurons. We found that GABA-induced inhibition is potentiated by local application of ISO in both control and chronic MA rats, suggesting that the reduction in DMI/GABA interactions is probably not mediated through post-synaptic noradrenergic mechanisms. Presynaptic NE clearance was further examined using in vivo chronoamperometric methods. Extracellular NE levels in the cerebellar cortex were measured using Nafion-coated carbon fiber sensors. We found that local application of DMI inhibited NE clearance in control rats, but not in chronic MA animals, suggesting that presynaptic NE clearance is reduced after chronic MA treatment. In addition, NE levels in cerebellar tissue were measured using HPLC-ECD. The NE concentration was significantly decreased in chronic MA rats. Taken together, our data suggest that regulation of uptake by DMI at central noradrenergic nerve terminals is abnormal after chronic MA exposure.

Activation of the small GTPases, rac and cdc42, after ligation of the platelet PAR-1 receptor

Stimulation of platelet PAR-1 receptors results in the rapid (10 to 30 seconds) and extensive (30% to 40% of total) guanosine triphosphate (GTP) charging of endogenous platelet rac, previously identified as a possible key intermediate in the signal pathway between PAR-1 and actin filament barbed-end uncapping, leading to actin assembly. During PAR-1-mediated platelet activation, rac distributes from the cell interior to the cell periphery, and this reorganization is resistant to the inhibition of PI-3-kinase activity. Rac, in resting or activated platelets, is Triton X-100 soluble, suggesting that it does not form tight complexes with actin cytoskeletal proteins, though its retention in octyl-glucoside-treated platelets and ultrastructural observations of activated platelets implies that rac binds to plasma membranes, where it can interact with phosphoinositide kinases implicated in actin assembly reactions. PAR-1 stimulation also rapidly and extensively activates cdc42, though, in contrast to rac, some cdc42 associates with the actin cytoskeleton in resting platelets, and the bound fraction increases during stimulation. The differences in subcellular distribution and previous evidence showing quantitatively divergent effects of rac and cdc42 on actin nucleation in permeabilized platelets indicate different signaling roles for these GTPases.

Solution structure of Apaf-1 CARD and its interaction with caspase-9 CARD: a structural basis for specific adaptor/caspase interaction

Direct recruitment and activation of caspase-9 by Apaf-1 through the homophilic CARD/CARD (Caspase Recruitment Domain) interaction is critical for the activation of caspases downstream of mitochondrial damage in apoptosis. Here we report the solution structure of the Apaf-1 CARD domain and its surface of interaction with caspase-9 CARD. Apaf-1 CARD consists of six tightly packed amphipathic alpha-helices and is topologically similar to the RAIDD CARD, with the exception of a kink observed in the middle of the N-terminal helix. By using chemical shift perturbation data, the homophilic interaction was mapped to the acidic surface of Apaf-1 CARD centered around helices 2 and 3. Interestingly, a significant portion of the chemically perturbed residues are hydrophobic, indicating that in addition to the electrostatic interactions predicted previously, hydrophobic interaction is also an important driving force underlying the CARD/CARD interaction. On the basis of the identified functional residues of Apaf-1 CARD and the surface charge complementarity, we propose a model of CARD/CARD interaction between Apaf-1 and caspase-9.

Increased production of antigen-specific immunoglobulins G and M following in vivo treatment with the medicinal plants Echinacea angustifolia and Hydrastis canadensis

A number of immunomodulatory effects have been attributed to the medicinal plants Echinacea angustifolia and Goldenseal (Hydrastis canadensis); however, little is known about whether treatment with these plants can enhance antigen-specific immunity. We investigated the antigen-specific in vivo immunomodulatory potential of continuous treatment with Echinacea and Goldenseal root extract over a period of 6 weeks using rats that were injected with the novel antigen keyhole limpet hemocyanin (KLH) and re-exposed to KLH after the initial exposure. Immunoglobulin production was monitored via ELISA continuously over a period of 6 weeks. The Echinacea-treated group showed a significant augmentation of their primary and secondary IgG response to the antigen, whereas the Goldenseal-treated group showed an increase in the primary IgM response during the first 2 weeks of treatment. Our results suggest that medicinal plants like Echinacea or Goldenseal may enhance immune function by increasing antigen-specific immunoglobulin production.

Intrapatient consistency of imaging biodistributions and their application to predicting therapeutic doses in a phase I clinical study of 90Y-based radioimmunotherapy

Intrapatient variation in the biodistribution of the chimeric monoclonal antibody cT84.66 was assessed in 19 patients having a variety of carcinoembryonic antigen (CEA) positive tumors. The two studies, including whole-body imaging and blood and urine specimen collections, were conducted within 14 days of each other using (111)In-cT84.66 at a fixed total protein dose of 5 mg per patient per study. An initial pretherapy infusion of (111)In-cT84.66 was administered followed by a therapy coinfusion of (111)In-ct84.66 and 90Y-cT84.66 A closed five-compartment model was used to integrate source organ activity curves as residence time inputs into the MIRDOSE3 program. Normal organ absorbed doses were estimated for 90Y-cT84.66, the corresponding radiotherapeutic agent. For the two (111)In-cT84.66 biodistributions, all data were modeled with a R2 value of between 0.72 and 1.00 with the exception of the urine data taken during therapy. This was due to the need of diethylenetriaminepentaacetic acid during the therapy phase because of the possibility that yttrium might escape from the chelator attached to the antibody. With the assurance that the biodistributions were reproducible, we were able to estimate the 90Y-cT84.66 absorbed doses on a per-patient basis. Concordance coefficients showing the agreement between the imaging and therapy phase dose estimates were between the 0.60 and 0.99 levels for liver, spleen, red marrow, total body, and other organ systems. Median results were: 27, 17, and 2.7 rad/mCi of 90Y-cT84.66 for liver, spleen, and red marrow, respectively. Because of decreases in platelets and white cells as the amount of 90Y was increased, dose-limiting toxicity was found at 22 mCi/m2. We conclude that patient biodistributions were consistent over time to 14 days so as to allow absorbed dose estimation in a radioimmunotherapy trial involving the cT84.66 anti-CEA antibody.

Using three-dimensional-computerized tomography as a diagnostic tool for temporo-mandibular joint ankylosis: a case report

Roentgenographic examination has long been a useful diagnostic tool for temporo-mandibular joint (TMJ) disease. The methods include TMJ tomography, panoramic radiography and computerized tomography (CT) scan with or without injection of contrast media. Recently, three-dimensional CT (3D-CT), reconstructed from the two-dimensional image of a CT scan to simulate the soft tissue or bony structure of the real target, was proposed. In this report, a case of TMJ ankylosis due to traumatic injury is presented. 3D-CT was employed as one of the presurgical roentgenographic diagnostic tools. The conventional radiographic examination including panoramic radiography and tomography showed lesions in both sides of the mandible. CT scanning further suggested that the right-sided lesion was more severe than that on the left. With 3D-CT image reconstruction the size and extent of the lesions were clearly observable. The decision was made to proceed with an initial surgical approach on the right side. With condylectomy and condylar replacement using an autogenous costochondral graft on the right side, the range of mouth opening improved significantly. In this case report, 3D-CT demonstrates its advantages as a tool for the correct and precise diagnosis of TMJ ankylosis.

Demonstration of adhesion activity of the soluble Ig-domain protein C-CAM4 by attachment to the plasma membrane

The carcinoembryonic antigen (CEA) family is a large group of proteins with immunoglobulin (Ig)-like structures. The membrane-associated CEA-family proteins have been shown to mediate intercellular adhesion. In addition to these membrane-associated proteins, several secreted CEA-like proteins, such as C-CAM4, PSG1b, and PSG11s, have also been identified. The functions of these soluble proteins are not clear because they cannot support intercellular adhesion like the membrane-associated proteins can. A fundamental question important for understanding the functions of these soluble proteins is whether they can interact in a homophilic fashion as do many of their membrane-associated homologues. We found that the homophilic interactions between these soluble proteins were too weak to be detected by solution binding assays. This is not unexpected because interactions between adhesion molecules are usually transient and weak to allow for control of association and dissociation. By expressing these soluble CEA-family proteins, C-CAM4, PSG1b, and PSG11s, as membrane-anchored forms, we showed that C-CAM4 could mediate intercellular adhesion, whereas PSG1b and PSG11s, despite their 52% identity to C-CAM4, could not. These results suggest that C-CAM4, but not PSG1b and PSG11s, can probably form homodimers. Thus, these secretory CEA-family members most likely have different interaction mechanisms, i.e., C-CAM4 might function as dimers, while PSGs might function as monomers.

Dynamic exercise leads to an increase in circulating ICAM-1: further evidence for adrenergic modulation of cell adhesion

Acute mental and physical stress lead to a marked lymphocytosis, with circulating natural killer cell numbers showing the most prominent increase. Many studies have linked these acute stress effects on lymphocytes with an increase in catecholamine levels. However, the molecular mechanisms which mediate this redistribution of lymphocytes from lymphocyte reservoirs into the circulation remain unknown. We hypothesized that this form of lymphocytosis was in part due to shedding of cell adhesion molecules from the cell surface and a subsequent detachment of lymphocytes adhering to the vascular endothelium in lymphocyte reservoirs. In this study, healthy human volunteers (n = 12) were exercised on a treadmill until exhaustion. The circulating levels of the soluble cell adhesion molecules ICAM-1 and E-Selectin were determined by ELISA. The subjects were then randomly assigned to treatment with either propranolol or metoprolol and repeated the exercise protocol after 1 week of treatment. Prior to drug treatment, soluble ICAM-1 levels rose from 258 +/- 19 to 321 +/- 28 ng/ml following exercise and returned to approximate baseline levels of 263 +/- 22 ng/ml after 1 h of rest. This highly significant effect of exercise on circulating ICAM-1 levels (p < .005) was mitigated after treatment with the beta-adrenergic antagonists. Soluble E-Selectin levels were not significantly affected by exercise. These results suggest that dynamic exercise leads to shedding of the cell adhesion molecule ICAM-1 via adrenergic mechanisms. We believe that these findings will contribute to the understanding of how physical and mental stress modulate lymphocyte migration and adhesion.

Pharmacokinetic modeling and absorbed dose estimation for chimeric anti-CEA antibody in humans

The objective of this article was to model pharmacokinetic data from clinical diagnostic studies involving the 111In-labeled monoclonal antibody (MAb) chimeric T84.66, against carcinoembryonic antigen. Model-derived results based on the 111In-MAb blood, urine and digital imaging data were used to predict 90Y-MAb absorbed radiation doses and to guide treatment planning for future therapy trials. Fifteen patients with at least one carcinoembryonic antigen-positive lesion were evaluated. We report the kinetic parameter estimates and absorbed 111In-MAb dose and projected 90Y-MAb doses for each patient as well as describe our approach and rationale for modeling an extensive set of pharmacokinetic data.

METHODS

The ADAPT II software package was used to create three- and five-compartment models of uptake against time in the patient population. The "best-fit" model was identified using ordinary least squares. Areas under the curve were calculated using the modeled curves and input into MIRDOSE3 to estimate absorbed radiation doses for each patient.

RESULTS

A five-compartment model best described the liver, whole body, blood and urine data for a subcohort of nine patients with digital imaging data. A three-compartment model best described the blood and urine data for all 15 clinical patients accrued in the clinical trial. For the subcohort, the largest projected 90Y-MAb doses were delivered to the liver (mean, 24.78 rad/mCi; range, 15.02-37.07 rad/mCi), with red marrow estimates on the order of 3.32 rad/mCi (range, 1.24-5.55) of 90Y. Corresponding estimates for the 111In-MAb were 3.18 (range, 2.09-4.43) and 0.55 (range, 0.34-0.74), respectively.

CONCLUSION

The three- and five-compartment models presented here were successfully used to represent the blood, urine and imaging data. This was evidenced by the small standard errors for the kinetic parameter estimates and R2 values close to 1. As planned future therapeutic trials will involve stem cell support to alleviate hematological toxicities, the development of an approach for estimating doses to other major organs is crucial.

Suppression of the phenotype of gamma(1)34.5- herpes simplex virus 1: failure of activated RNA-dependent protein kinase to shut off protein synthesis is associated with a deletion in the domain of the alpha47 gene

Earlier studies have shown that infection of human cells by herpes simplex virus 1 (HSV-1) results in the activation of RNA-dependent protein kinase (PKR) but that the alpha subunit of eIF-2 is not phosphorylated and that protein synthesis is unaffected. In the absence of the viral gamma(1)34.5 gene, eIF-2alpha is phosphorylated and protein synthesis is prematurely shut off (J. Chou, J. J. Chen, M. Gross, and B. Roizman, Proc. Natl. Acad. Sci. USA 92:10516-10520, 1995). A second recent paper reported the selection of second-site suppressor mutants characterized by near-wild-type protein synthesis in cells infected with gamma(1)34.5- mutants (I. Mohr and Y. Gluzman, EMBO J. 15:4759-4766, 1996). Here, we report the properties of the spontaneous HSV-1 suppressor mutant Sup-1, which is characterized by spontaneous deletion of 503 bp encompassing the domain of the alpha47 gene and junction with the inverted repeats flanking the unique short (U(S)) sequence of the HSV-1 DNA resulting in the juxtaposition of the alpha47 promoter to the coding domain of the U(S)11 gene. This mutant does not exhibit the shutoff of protein synthesis characteristic of the gamma(1)34.5- virus. Specifically, Sup-1 in SK-N-SH human neuroblastoma cells (i) did not exhibit the function of the alpha47 gene characterized by a reduction in the transport of peptides across the endoplasmic reticulum of permealized cells consistent with the absence of alpha47 gene sequences, (ii) accumulated U(S)11 protein at levels analogous to those of the wild-type parent but the protein was made at earlier times after infection, as would be expected from a change in the promoter, and (iii) activated PKR like that of the parent, gamma(1)34.5- virus, but (iv) did not cause premature shutoff of protein synthesis and therefore was similar to the wild-type parent virus rather than the gamma(1)34.5- virus from which it was derived. We conclude that the mechanism by which Sup-1 blocks the shutoff of protein synthesis associated with phosphorylation of eIF-2alpha by the activated PKR is not readily explainable by a secondary mutation characterized by a deletion.

Evaluation of genetically engineered herpes simplex viruses as oncolytic agents for human malignant brain tumors

Earlier studies have shown that genetically engineered herpes simplex viruses (e.g., HSV-1) are effective in killing malignant tumor cells both in vitro and in various murine tumor models. This report focuses on a panel of five genetically engineered viral mutants of the gamma(1)34.5 gene, which was shown previously to cause reduction in viral replication and associated neurovirulence of HSV. These include R3616, which has both copies of gamma(1)34.5 deleted, R4009, which has a stop codon inserted after codon 28 in both copies of the gamma(1)34.5 gene, R849, which contains a lacZ gene inserted in place of the gamma(1)34.5, R908, which lacks 41 codons in frame after codon 72 of the gamma(1)34.5, and R939, which carries a stop codon precluding the translation of the COOH-terminal domain of the gamma(1)34.5 gene. We report the following: (a) all five mutant HSVs were avirulent in experimental animals but were cytotoxic for human tumor cells in vitro and in vivo; (b) the gamma(1)34.5- HSV replicated in human glioma cells almost as efficiently as wild-type HSV-1(F) based on replication assays, in situ hybridization for viral DNA, and expression of infected cell protein 27; (c) capacity of mutant HSVs to kill human cells derived from glioblastoma multiforme (CH-235MG, D-37MG, D-54MG, D-65MG, U-251MG, U-373MG, and SK-MG-1), anaplastic astrocytoma (Hs-683), anaplastic glioma (U-87MG and U-138MG), gliosarcoma (D-32GS), or normal human astrocytes demonstrated that glioma cells varied in their susceptibility to HSV-mediated cytotoxicity and that cultured astrocytes were two to three orders of magnitude less susceptible to killing than were malignant glia; and (d) scid mice, which received 0.5 or 5 x 10(6) plaque-forming units of R4009, either were coinoculated at the time of intracranial transplantation with 106 U251MG or D-54MG human glioma cells or received the cells intratumorally 5 days after tumor induction and experienced significant increases in median survivals, with no histopathological indication of an infectious encephalitic process. Genetically engineered gamma(1)34.5- HSV mutants appear to be a potentially safe biotherapeutic agent for experimental treatment of uniformly fatal malignant brain tumors.

[Study of interaction between cytochrome C and cystine using synchronours fluorescence spectroscopy]

The interaction of cytochrome C with cystine as promoter was studied by synchronous fluorescence spectroscopy. After cystine was added into cytochrome C solution, the synchronous flurorescence spectra of tyrosine and tryptophan residues in cytochrome C were monitered with time. The results indicated that the lysine residues in cytochrome C molecules combine with cystine slowly. It induced the small conformational change of cytochrome C molecules.

The application of genetically engineered herpes simplex viruses to the treatment of experimental brain tumors

Due to lack of effective therapy, primary brain tumors are the focus of intense investigation of novel experimental approaches that use vectors and recombinant viruses. Therapeutic approaches have been both indirect, whereby vectors are used, or direct to allow for direct cell killing by the introduced virus. Genetically engineered herpes simplex viruses are currently being evaluated as an experimental approach to eradicate malignant human gliomas. Initial studies with gamma (1)34.5 mutants, R3616 (from which both copies of the gamma (1)34.5 gene have been deleted) and R4009 (a construct with two stop codons inserted into the gamma (1)34.5 gene), have been assessed. In a syngeneic scid mouse intracranial tumor model, recombinant herpes simplex virus can be experimentally used for the treatment of brain tumors. These viruses and additional engineered viruses were subsequently tested in human glioma cells both in vitro and in vivo. Using a xenogeneic scid mouse intracranial glioma model, R4009 therapy of established tumors significantly prolonged survival. Most importantly, long-term survival was achieved, with histologic evidence that R4009 eradicated intracranial tumors in this model. Furthermore, the opportunity to evaluate gamma (1)34.5 mutants that have enhanced oncolytic activity, e.g., R8309 where the carboxyl terminus of the gamma (1)34.5 gene has been replaced by the murine homologue, MyD116, are considered.

Identification of a new isoform of cell-cell adhesion molecule 105 (C-CAM), C-CAM4: a secretory protein with only one Ig domain

A series of Southern blot hybridization experiments using probes derived from different regions of the rat liver cell-cell adhesion molecule 105 (C-CAM) cDNA revealed the presence of a 9.6 kb EcoRI genomic fragment that seemed to encode a unique C-CAM isoform. An RNase protection study showed that this c-CAM transcript was expressed in placenta, spleen, lung and large intestine. In contrast, the other C-CAM isoforms, C-CAM1 and C-CAM2, are expressed in liver and small intestine. This result also suggests that the new isoform, which we named C-CAM4, was indeed encoded by a new C-CAM gene. A rat placenta cDNA library was then screened and the full-length cDNA coding for C-CAM4 was isolated. The deduced protein contained 142 amino acids and had a calculated molecular mass of 15 kDa. C-CAM4 was composed of a leader sequence and the first V-like Ig domain typical of C-CAM-family proteins. However, C-CAM4 lacked the C-like Ig domains, the transmembrane domain, and the cytoplasmic domain found in other C-CAM isoforms. Thus, C-CAM4 is different from the other known C-CAMs in that it is a secreted protein. We have previously shown that the first Ig domain of C-CAM1 is crucial for its adhesion function. The V-like Ig domain of C-CAM4 had 92% and 89% sequence identity with the corresponding regions of C-CAM1 and C-cam2 respectively. Together these results suggest that C-CAM4 may play a role in regulating the function of other C-CAM family proteins.

The carboxyl terminus of the murine MyD116 gene substitutes for the corresponding domain of the gamma(1)34.5 gene of herpes simplex virus to preclude the premature shutoff of total protein synthesis in infected human cells

The herpes simplex virus 1 mutants from which both copies of the gamma(1)34.5 gene had been deleted trigger total shutoff of protein synthesis in human neuroblastoma cells and human foreskin fibroblasts but not in African green monkey (Vero) cells. The carboxyl-terminal 64 amino acids of gamma(1)34.5 are homologous to the corresponding domain of MyD116, a murine myeloid differentiation primary responsive gene. The carboxyl-terminal domain of gamma(1)34.5 is required to preclude the shutoff of protein synthesis (J. Chou and B. Roizman, Proc. Natl. Acad. Sci. USA 91:5247-5251, 1994). We report that in-frame substitution of the carboxyl terminus of gamma(1)34.5 with the corresponding domain of MyD116 in the context of the viral genome restored the ability of gamma(1)34.5 to preclude premature shutoff of protein synthesis in both neuroblastoma cells and in human foreskin fibroblasts. The results suggest that (i) in the course of its evolution, the virus "borrowed" a gene fragment to preclude a cell response to infection and (ii) the carboxyl terminus of MyD116 and its family of genes known as GADD34 may have a similar function(s) in cells stressed by growth arrest, DNA damage, and differentiation and in herpes simplex virus infection.

Association of a M(r) 90,000 phosphoprotein with protein kinase PKR in cells exhibiting enhanced phosphorylation of translation initiation factor eIF-2 alpha and premature shutoff of protein synthesis after infection with gamma 134.5- mutants of herpes simplex virus 1

The protein encoded by the gamma 134.5 gene of herpes simplex virus precludes premature shutoff of protein synthesis in human cells triggered by stress associated with onset of viral DNA synthesis. The carboxyl terminus of the protein is essential for this function. This report indicates that the shutoff of protein synthesis is not due to mRNA degration because mRNA from wild-type or gamma 134.5- virus-infected cells directs protein synthesis. Analyses of the posttranslational modifications of translation initiation factor eIF-2 showed the following: (i) eIF-2 alpha was selectively phosphorylated by a kinase present in ribosome-enriched fraction of cells infected with gamma 134.5- virus. (ii) Endogenous eIF-2 alpha was totally phosphorylated in cells infected with gamma 134.5- virus or a virus lacking the 3' coding domain of the gamma 134.5 gene but was not phosphorylated in mock-infected or wild-type virus-infected cells. (iii) Immune precipitates of the PKR kinase that is responsible for regulation of protein synthesis of some cells by phosphorylation of eIF-2 alpha yielded several phosphorylated polypeptides. Of particular significance were two observations. First, phosphorylation of PKR kinase was elevated in all infected cells relative to the levels in mock-infected cells. Second, the precipitates from lysates of cells infected with gamma 134.5- virus or a virus lacking the 3' coding domain of the gamma 134.5 gene contained an additional labeled phosphoprotein of M(r) 90,000 (p90). This phosphoprotein was present in only trace amounts in the immunoprecipitate from cells infected with wild-type virus or mutants lacking a portion of the 5' domain of gamma 134.5. We conclude that in the absence of gamma 134.5 protein, PKR kinase complexes with the p90 phosphoprotein and shuts off protein synthesis by phosphorylation of the alpha subunit of translation initiation factor eIF-2.

A new neurohypophysial peptide, seritocin ([Ser5,Ile8]-oxytocin), identified in a dryness-resistant African toad, Bufo regularis

From the pituitary neurointermediate lobe of the African toad Bufo regularis, vasotocin, hydrin 2 (vasotocinyl-Gly) and a mesotocin-like peptide have been isolated by HPLC and characterized by mass spectrometry, amino acid sequence and chromatographic coelution with synthetic peptides. The mesotocin-like peptide has been identified as [Ser5,Ile8]-oxytocin in place of mesotocin ([Ile8]-oxytocin) found in all other amphibians investigated to date. The name seritocin is suggested. The molecule is virtually devoid of oxytocic activity on rat uterus in contrast to mesotocin. On the other hand, the molar ratio of hydrin 2 to vasotocin in the pituitary reaches 2, whereas it is about 1 in toads and frogs from temperate regions. B. regularis is an anuran species able to withstand a hot and dry season by burrowing. The possible relationship between occurrence of seritocin and adaptation to arid environment remains to be demonstrated.

Comparison of genetically engineered herpes simplex viruses for the treatment of brain tumors in a scid mouse model of human malignant glioma

Genetically engineered viruses and viral genes inserted into retroviral vectors are increasingly being considered for experimental therapy of brain tumors. A primary target of these viruses and vectors is human gliomas, the most frequently occurring primary human brain tumor. To investigate the potential of genetically engineered herpes simplex viruses (HSVs) in the therapy of these tumors, we compared the attributes of two viruses, a recombinant from which the gamma 1(34.5) gene had been deleted (R3616) and a recombinant in which the gamma 1(34.5) gene had been interrupted by a stop codon (R4009). Previous studies have shown that these recombinants were completely devoid of the ability to multiply in the central nervous system of rodents. To pursue these studies, we developed a scid mouse glioma model. Tumor cell response (survival) for 10(3), 10(4), and 10(5) implanted MT539MG glioma cells was 38, 23, and 15 days, respectively. The results were as follows: (i) both R3616 and R4009 replicate and cause cytolysis in diverse glioma cell lines of murine and human origin in vitro, and (ii) Winn-type assays 10(5) MT539MG cells coinoculated with R3616 or R4009 as compared to saline significantly prolonged survival in a dose-dependent fashion. Mice that received only tumor cells or the wild-type parent strain of the recombinants, HSV-1(F), died within 15 days. Survival was greatest with R4009. These experiments define both a model for screening oncolytic viruses and a genetically engineered virus of significant potential use as an oncolytic agent.