Single-cell RNA sequencing reveals the cellular and molecular heterogeneity of treatment-naïve primary osteosarcoma in dogs

Osteosarcoma (OS) is a heterogeneous, aggressive malignancy of the bone that disproportionally affects children and adolescents. Therapeutic interventions for OS are limited, which is in part due to the complex tumor microenvironment (TME). As such, we used single-cell RNA sequencing (scRNA-seq) to describe the cellular and molecular composition of the TME in 6 treatment-naïve dogs with spontaneously occurring primary OS. Through analysis of 35,310 cells, we identified 41 transcriptomically distinct cell types including the characterization of follicular helper T cells, mature regulatory dendritic cells (mregDCs), and 8 tumor-associated macrophage (TAM) populations. Cell-cell interaction analysis predicted that mregDCs and TAMs play key roles in modulating T cell mediated immunity. Furthermore, we completed cross-species cell type gene signature homology analysis and found a high degree of similarity between human and canine OS. The data presented here act as a roadmap of canine OS which can be applied to advance translational immuno-oncology research.

Targeting osteosarcoma with canine B7-H3 CAR T cells and impact of CXCR2 Co-expression on functional activity

The use of large animal spontaneous models of solid cancers, such as dogs with osteosarcoma (OS), can help develop new cancer immunotherapy approaches, including chimeric antigen receptor (CAR) T cells. The goal of the present study was to generate canine CAR T cells targeting the B7-H3 (CD276) co-stimulatory molecule overexpressed by several solid cancers, including OS in both humans and dogs, and to assess their ability to recognize B7-H3 expressed by canine OS cell lines or by canine tumors in xenograft models. A second objective was to determine whether a novel dual CAR that expressed a chemokine receptor together with the B7-H3 CAR improved the activity of the canine CAR T cells. Therefore, in the studies reported here we examined B7-H3 expression by canine OS tumors, evaluated target engagement by canine B7-H3 CAR T cells in vitro, and compared the relative effectiveness of B7-H3 CAR T cells versus B7-H3-CXCR2 dual CAR T cells in canine xenograft models. We found that most canine OS tumors expressed B7-H3; whereas, levels were undetectable on normal dog tissues. Both B7-H3 CAR T cells demonstrated activation and OS-specific target killing in vitro, but there was significantly greater cytokine production by B7-H3-CXCR2 CAR T cells. In canine OS xenograft models, little anti-tumor activity was generated by B7-H3 CAR T cells; whereas, B7-H3-CXCR2 CAR T cells significantly inhibited tumor growth, inducing complete tumor elimination in most treated mice. These findings indicated therefore that addition of a chemokine receptor could significantly improve the anti-tumor activity of canine B7-H3 CAR T cells, and that evaluation of this new dual CAR construct in dogs with primary or metastatic OS is warranted since such studies could provide a critical and realistic validation of the chemokine receptor concept.

Targeted transcriptomic analysis of synovial tissues from horses with septic arthritis treated with immune-activated mesenchymal stromal cells reveals induction of T-cell response pathways

OBJECTIVE

To investigate mechanistically the reported beneficial effects of immune-activated mesenchymal stromal cell (MSC) therapy to treat equine septic arthritis, leveraging Nanostring technology.

ANIMALS

8 Quarter Horses with induced tibiotarsal Staphylococcus aureus septic arthritis treated IA with either Toll-like receptor-3 agonist polyinosinic:polycytidylic acid-activated MSCs + vancomycin antimicrobials (TLR-MSC-VAN; n = 4) or antimicrobials (VAN; 4).

METHODS

Synovial tissues were collected and fixed in neutral-buffered 10% formalin, and formalin-fixed paraffin-embedded synovial and osteochondral tissues were sequenced using a custom-designed 200-gene equine Nanostring nCounter immune panel to directly quantify expression of key immune and cartilage-related genes. Immunohistochemistry to detect CD3+ T cells was performed on synovial tissues to further quantify T-cell infiltration in TLR-MSC-VAN- versus VAN-treated joints.

RESULTS

Comparison of synovial transcriptomes between groups revealed moderate changes in differential gene expression, with upregulated expression of 9 genes and downregulated expression of 17 genes with fold change ≥ 2 or ≤ -2 and a significant false discovery rate-adjusted P value of ≤ .05. The most upregulated genes in TLR-MSC-VAN-treated horses included those related to T-lymphocyte recruitment and function, while pathways related to innate immune activation and inflammation were significantly downregulated. Immunohistochemistry and quantitation of CD3+ T-cell infiltrates revealed a numerically greater infiltrate in synovial tissues of TLR-MSC-VAN-treated horses, which did not reach statistical significance in this small sample set (P = .20).

CLINICAL RELEVANCE

Targeted transcriptomic analyses using an equine Nanostring immune and cartilage health panel provided new mechanistic insights into how innate and adaptive immune cells within synovial tissues respond to TLR-activated MSC treatment when used to treat septic arthritis.

Single-cell RNA sequencing reveals the cellular and molecular heterogeneity of treatment-naïve primary osteosarcoma in dogs

Osteosarcoma (OS) is a heterogeneous, aggressive malignancy of the bone that disproportionally affects children and adolescents. Therapeutic interventions for OS are limited, which is in part due to the complex tumor microenvironment (TME) that has proven to be refractory to immunotherapies. Thus, there is a need to better define the complexity of the OS TME. To address this need, we used single-cell RNA sequencing (scRNA-seq) to describe the cellular and molecular composition of the TME in 6 treatment-naïve dogs with spontaneously occurring primary OS. Through analysis of 35,310 cells, we identified 30 distinct immune cell types, 9 unique tumor populations, 1 cluster of fibroblasts, and 1 cluster of endothelial cells. Independent reclustering of major cell types revealed the presence of follicular helper T cells, mature regulatory dendritic cells (mregDCs), and 8 transcriptomically distinct macrophage/monocyte populations. Cell-cell interaction inference analysis predicted that mregDCs and tumor-associated macrophages (TAMs) play key roles in modulating T cell mediate immunity. Furthermore, we used publicly available human OS scRNA-seq data to complete a cross-species cell type gene signature homology analysis. The analysis revealed a high degree of cell type gene signature homology between species, suggesting the cellular composition of OS is largely conserved between humans and dogs. Our findings provide key new insights into the biology of canine OS and highlight the conserved features of OS across species. Generally, the data presented here acts as a cellular and molecular roadmap of canine OS which can be applied to advance the translational immuno-oncology research field.

A single-cell RNA sequencing atlas of circulating leukocytes from healthy and osteosarcoma affected dogs

Translationally relevant animal models are essential for the successful translation of basic science findings into clinical medicine. While rodent models are widely accessible, there are numerous limitations that prevent the extrapolation of findings to human medicine. One approach to overcome these limitations is to use animal models that are genetically diverse and naturally develop disease. For example, pet dogs spontaneously develop diseases that recapitulate the natural progression seen in humans and live in similar environments alongside humans. Thus, dogs represent a useful animal model for many areas of research. Despite the value of the canine model, species specific reagent limitations have hampered in depth characterization of canine immune cells, which constrains the conclusions that can be drawn from canine immunotherapy studies. To address this need, we used single-cell RNA sequencing to characterize the heterogeneity of circulating leukocytes in healthy dogs (n = 7) and osteosarcoma (OS) affected dogs (n = 10). We present a cellular atlas of leukocytes in healthy dogs, then employ the dataset to investigate the impact of primary OS tumors on the transcriptome of circulating leukocytes. We identified 36 unique cell populations amongst dog circulating leukocytes, with a remarkable amount of heterogeneity in CD4 T cell subtypes. In our comparison of healthy dogs and dogs with OS, we identified relative increases in the abundances of polymorphonuclear (PMN-) and monocytic (M-) myeloid-derived suppressor cells (MDSCs), as well as aberrations in gene expression within myeloid cells. Overall, this study provides a detailed atlas of canine leukocytes and investigates how the presence of osteosarcoma alters the transcriptional profiles of circulating immune cells.

Evaluation of Immune Nanoparticles for Rapid and Non-Specific Activation of Antiviral and Antibacterial Immune Responses in Cattle, Swine, and Poultry

Given the rapid potential spread of agricultural pathogens, and the lack of vaccines for many, there is an important unmet need for strategies to induce rapid and non-specific immunity against these viral and bacterial threats. One approach to the problem is to generate non-specific immune responses at mucosal surfaces to rapidly protect from entry and replication of both viral and bacterial pathogens. Using complexes of charged nanoparticle liposomes with both antiviral and antibacterial toll-like receptor (TLR) nucleic acid ligands (termed liposome-TLR complexes or LTC), we have previously demonstrated considerable induction of innate immune responses in nasal and oropharyngeal tissues and protection from viral and bacterial pathogens in mixed challenge studies in rodents, cattle, and companion animals. Therefore, in the present study, we used in vitro assays to evaluate the ability of the LTC immune stimulant to activate key innate immune pathways, particularly interferon pathways, in cattle, swine, and poultry. We found that LTC complexes induced strong production of type I interferons (IFNα and IFNβ) in both macrophages and leukocyte cultures from all three species. In addition, the LTC complexes induced the production of additional key protective cytokines (IL-6, IFNγ, and TNFα) in macrophages and leukocytes in cattle and poultry. These findings indicate that the LTC mucosal immunotherapeutic has the capability to activate key innate immune defenses in three major agricultural species and potentially induce broad protective immunity against both viral and bacterial pathogens. Additional animal challenge studies are warranted to evaluate the protective potential of LTC immunotherapy in cattle, swine, and poultry.

Intravenous injection of adipose-derived mesenchymal stromal cells benefits gait and inflammation in a spontaneous osteoarthritis model

Osteoarthritis (OA) is a leading cause of morbidity among aging populations, yet symptom and/or disease-modification remains elusive. Adipose-derived mesenchymal stromal cells (adMSCs) have demonstrated immunomodulatory and anti-inflammatory properties that may alleviate clinical signs and interrupt disease onset and progression. Indeed, multiple manuscripts have evaluated intra-articular administration of adMSCs as a therapeutic; however, comparatively few evaluations of systemic delivery methods have been published. Therefore, the aim of this study was to evaluate the short-term impact of intravenous (IV) delivery of allogeneic adMSCs in an established model of spontaneous OA, the Hartley guinea pig. Animals with moderate OA received once weekly injections of 2 × 106 adMSCs or vehicle control for 4 weeks in peripheral veins; harvest occurred 2 weeks after the final injection. Systemic administration of adMSCs resulted in no adverse effects and was efficacious in reducing clinical signs of OA (as assessed by computer-aided gait analysis) compared to control injected animals. Further, there were significant decreases in key inflammatory mediators (including monocyte chemoattractant protein-1, tumor necrosis factor, and prostaglandin E2 ) both systemically (liver, kidney, and serum) and locally in the knee (joint tissues and synovial fluid) in animals treated with IV adMSCs relative to controls (as per enzyme-linked immunosorbent assay and/or immunohistochemistry, dictated by tissue sample). Thus, systemic administration of adMSCs by IV injection significantly improved gait parameters and reduced both systemic and intra-articular inflammatory mediators in animals with OA. These findings demonstrate the potential utility of alternative delivery approaches for cellular therapy of OA, particularly for patients with multiple affected joints.

Reprogramming the Canine Glioma Microenvironment with Tumor Vaccination plus Oral Losartan and Propranolol Induces Objective Responses

Purpose

Malignant gliomas have a highly immune suppressive tumor microenvironment (TME) which renders them largely unresponsive to conventional therapeutics. Therefore, the present study evaluated a therapeutic protocol designed overcome the immune barrier by combining myeloid cell targeted immunotherapy with tumor vaccination.

Experimental Design

We utilized a spontaneously occurring canine glioma model to investigate an oral TME modifying immunotherapy in conjunction with cancer stem cell (CSC) vaccination. Dogs were treated daily with losartan (monocyte migration inhibitor) and propranolol (myeloid-derived suppressor cell depleting agent) plus anti-CSC vaccination on a bi-weekly then monthly schedule. Tumor volume was monitored by MRI and correlated with patient immune responses.

Results

Ten dogs with histologically confirmed gliomas were enrolled into a prospective, open-label clinical trial to evaluate the immunotherapy protocol. Partial tumor regression was observed in 2 dogs, while 6 dogs experienced stable disease, for an overall clinical benefit rate of 80%. Overall survival times (median = 351 days) and progression-free intervals (median = 163 days) were comparable to prior studies evaluating surgical debulking followed by immunotherapy. Dogs with detectable anti-CSC antibody responses had an increased overall survival time relative to dogs that did not generate antibody responses (vaccine responder MST = 500 days; vaccine non-responder MST = 218 days; p = 0.02).

Conclusions

These findings suggest that combining myeloid cell targeted oral immunotherapy with tumor vaccination can generate objective tumor responses, even in the absence of conventional therapy. Overall, this approach has promise as a readily implemented therapeutic strategy for use in brain cancer patients.

Local immune and microbiological responses to mucosal administration of a Liposome-TLR agonist immunotherapeutic in dogs

Background

Non-specific immunotherapeutics have been evaluated previously in dogs, primarily for cancer treatment. However, there remains a need for a more broadly targeted, general purpose immunotherapeutic capable of activating innate immune defenses for non-specific protection or early treatment of viral and bacterial infections. To address need, our group has developed a liposomal immune stimulant (liposome-TLR complexes, LTC) containing TLR 3 and 9 agonists specifically designed to activate mucosal immune defenses in sites such as nasal cavity and oropharynx, following topical delivery. In this study, we evaluated the local immune stimulatory properties of LTC in vitro and in healthy purpose-bred dogs, including activation of cellular recruitment and cytokine production. The ability of LTC treatment to elicit effective antiviral immunity was assessed in dogs following a canine herpesvirus outbreak, and the impact of LTC treatment on the local microbiome of the oropharynx was also investigated.

Results

These studies revealed that LTC potently activated innate immune responses in vitro and triggered significant recruitment of inflammatory monocytes and T cells into the nasal cavity and oropharynx of healthy dogs. Administration of LTC to dogs shortly after an outbreak of canine herpesvirus infection resulted in significant reduction in clinical signs of infection. Interestingly, administration of LTC to healthy dogs did not disrupt the microbiome in the oropharynx, suggesting resiliency of the microflora to transient immune activation.

Conclusions

Taken together, these results indicate that LTC administration mucosally to dogs can trigger local innate immune activation and activation of antiviral immunity, without significantly disrupting the composition of the local microbiome. Thus, the LTC immune stimulant has potential for use as a non-specific immunotherapy for prevention or early treatment of viral and bacterial infections in dogs.

Activated Mesenchymal Stem Cells Interact with Antibiotics and Host Innate Immune Responses to Control Chronic Bacterial Infections

Chronic bacterial infections associated with biofilm formation are often difficult to resolve without extended courses of antibiotic therapy. Mesenchymal stem cells (MSC) exert antibacterial activity in vitro and in acute bacterial infection models, but their activity in chronic infection with biofilm models has not been previously investigated. Therefore, we studied the effects of MSC administration in mouse and dog models of chronic infections associated with biofilms. Mice with chronic Staphylococcus aureus implant infections were treated by i.v. administration of activated or non-activated MSC, with or without antibiotic therapy. The most effective treatment protocol was identified as activated MSC co-administered with antibiotic therapy. Activated MSC were found to accumulate in the wound margins several days after i.v. administration. Macrophages in infected tissues assumed an M2 phenotype, compared to untreated infections which contained predominately M1 macrophages. Bacterial killing by MSC was found to be mediated in part by secretion of cathelicidin and was significantly increased by antibiotics. Studies in pet dogs with spontaneous chronic multi drug-resistant wound infections demonstrated clearance of bacteria and wound healing following repeated i.v. administration of activated allogeneic canine MSC. Thus, systemic therapy with activated MSC may be an effective new, non-antimicrobial approach to treatment of chronic, drug-resistant infections.

Role of monocyte recruitment in hemangiosarcoma metastasis in dogs

Canine hemangiosarcoma (HSA) is a highly malignant tumour associated with short survival times because of early and widespread metastasis. In humans and rodents, monocytes play key roles in promoting tumour metastasis through stimulating tumour cell extravasation, seeding, growth and angiogenesis. Therefore, we investigated the potential association between monocyte infiltration and tumour metastasis in HSA and other common canine tumours. Immunohistochemistry was used to quantify CD18⁺ monocytes within metastases. We found that HSA metastases had significantly greater numbers of CD18⁺ monocytes compared with metastases from other tumour types. HSA cells were the highest producers of the monocyte chemokine CCL2, and stimulated canine monocyte migration in a CCL2 dependent manner. These results are consistent with the hypothesis that overexpression of CCL2 and recruitment of large numbers of monocytes may explain in part the aggressive metastatic nature of canine HSA. Thus, therapies designed to block monocyte recruitment may be an effective adjuvant strategy for suppressing HSA metastasis in dogs.

Immune regulation of canine tumour and macrophage PD-L1 expression

Expression of programmed cell death receptor ligand 1 (PD-L1) on tumor cells has been associated with immune escape in human and murine cancers, but little is known regarding the immune regulation of PD-L1 expression by tumor cells and tumor-infiltrating macrophages in dogs. Therefore, 14 canine tumor cell lines, as well as primary cultures of canine monocytes and macrophages, were evaluated for constitutive PD-L1 expression and for responsiveness to immune stimuli. We found that PD-L1 was expressed constitutively on all canine tumor cell lines evaluated, although the levels of basal expression were very variable. Significant upregulation of PD-L1 expression by all tumor cell lines was observed following IFN-γ exposure and by exposure to a TLR3 ligand. Canine monocytes and monocyte-derived macrophages did not express PD-L1 constitutively, but did significantly upregulate expression following treatment with IFN-γ. These findings suggest that most canine tumors express PD-L1 constitutively and that both innate and adaptive immune stimuli can further upregulate PD-L1 expression. Therefore the upregulation of PD-L1 expression by tumor cells and by tumor-infiltrating macrophages in response to cytokines such as IFN-γ may represent an important mechanism of tumor-mediated T-cell suppression in dogs as well as in humans.

RP105 Engages Phosphatidylinositol 3-Kinase p110δ To Facilitate the Trafficking and Secretion of Cytokines in Macrophages during Mycobacterial Infection

Cytokines are key regulators of adequate immune responses to infection with Mycobacterium tuberculosis. We demonstrate that the p110δ catalytic subunit of PI3K acts as a downstream effector of the TLR family member RP105 (CD180) in promoting mycobacteria-induced cytokine production by macrophages. Our data show that the significantly reduced release of TNF and IL-6 by RP105(-/-) macrophages during mycobacterial infection was not accompanied by diminished mRNA or protein expression. Mycobacteria induced comparable activation of NF-κB and p38 MAPK signaling in wild-type (WT) and RP105(-/-) macrophages. In contrast, mycobacteria-induced phosphorylation of Akt was abrogated in RP105(-/-) macrophages. The p110δ-specific inhibitor, Cal-101, and small interfering RNA-mediated knockdown of p110δ diminished mycobacteria-induced TNF secretion by WT but not RP105(-/-) macrophages. Such interference with p110δ activity led to reduced surface-expressed TNF in WT but not RP105(-/-) macrophages, while leaving TNF mRNA and protein expression unaffected. Activity of Bruton's tyrosine kinase was required for RP105-mediated activation of Akt phosphorylation and TNF release by mycobacteria-infected macrophages. These data unveil a novel innate immune signaling axis that orchestrates key cytokine responses of macrophages and provide molecular insight into the functions of RP105 as an innate immune receptor for mycobacteria.

Intraoperative electro-oculographic Monitoring for Skull Base Surgery

During surgery on the skull base, preservation of the integrity of the ocular motor nerves is vitally important. Intraoperative electrophysiological monitoring methods for protecting such functions have been reported by several investigators. However, these methods so far have not been popularized sufficiently, due to the difficulty and complexity of the procedures involved. The authors have developed an extremely simple but far more reliable method using electro-oculography under total intravenous anesthesia with propofol to preserve the integrity of the ocular motor nerves. The ocular motor nerves were stimulated with a monopolar electrode intracranially, and the polarity of the waves was recorded using surface electrodes placed around the eyeball, yielding precise information concerning the locations of the oculomotor nerve and/or abducent nerve. In addition, by performing continuous monitoring, invasive procedures affecting the ocular motor nerves could be detected as spontaneous ocular movements. In practice at our department, this method has been applied in 12 cases with tumors close to the ocular motor nerves, and has produced excellent results.

FK506 attenuates the post-ischemic perturbation of protein kinases and tyrosine phosphorylation in the gerbil hippocampal CA1 sectors

To explore effects of Immunosuppressant FK506 on signal transduction pathway. we studied changes in subcellular distribution of protein kinase Cgamma (PKCgamma), CaM kinase II (CaMKII), as well as changes of tyrosine phosphorylation levels after ischemia. Male Mongolian gerbils were divided into 3 groups; FK506 (1 mg/kg, 3 mg/kg) and vehicle. FK506 was administered intravenously after 5 min ischemia. At the designated time points (0 time, 5 min ischemia, 1 hour, or 24 hour recovery), heads were frozen and samples were taken from CAI subfield of hippocampus. Western blot analysis was carried out with specific antibodies for PKCgamma, CaMKII, and phosphotyrosine. FK506 administration significantly decreased translocation of PKCgamma and CaMKII at 24 h of recovery (p < 0.05, ANOVA followed by Student-Newman Keuls' test) in P2 fraction. The levels of tyrosine phosphorylated p160, p140, p100, p90, and p80 in P2 fraction were also significantly decreased with FK506 treatment at 24 h of recovery. The persistently elevated PKCgamma and CaMKII level in P2 fraction which may be related to cell death, are attenuated with FK506 treatment. FK506 may contribute to recover calcium homeostasis in the post ischemic phase and promote cell survival.

Ischemic pre-conditioning affects the subcellular distribution of protein kinase C and calcium/calmodulin-dependent protein kinase II in the gerbil hippocampal CA1 neurons

Brief ischemic episode, which in itself is not lethal, confers tolerance to subsequent ischemic insults. Since intracellular signal transduction system has been implicated in ischemic cell death, we studied the effect of pre-conditioning on the changes in the subcellular distribution of protein kinase Cgamma (PKCgamma) as well as CaM kinase II (CaMKII). Gerbils were pre-conditioned by a sublethal 2 min cerebral ischemia 24 h prior to lethal 5 min ischemia. The pre-conditioning generally downregulated PKCgamma and CaMKII in the CA1 hippocampus. Especially at the starting point of the second lethal ischemia, the cytosolic PKCgamma level was about 40% lower in the pre-conditioned group. Also, the crude synaptosomal CaMKII level at 24 h reperfusion following the second ischemia was significantly lower in the pre-conditioned group, showing enhanced recovery of CaMKII translocation. Present results suggest that ischemic pre-conditioning may downregulate calcium-mediated cell signaling system, enhancing normalization of calcium homeostasis, perturbed by the second ischemia of lethal duration.

Comparative analysis of the Band 4.1/ezrin-related protein tyrosine phosphatase Pez from two Drosophila species: implications for structure and function

The FERM-PTPs are a group of proteins that have FERM (Band 4.1, ezrin, radixin, moesin homology) domains at or near their N-termini, and PTP (protein tyrosine phosphatase) domains at their C-termini. Their central regions contain either PSD-95, Dlg, ZO-1 homology domains or putative Src homology 3 domain binding sites. The known FERM-PTPs fall into three distinct classes, which we name BAS, MEG, and PEZ, after representative human PTPs. Here we analyze Pez, a novel gene encoding the single PEZ-class protein present in Drosophila. Pez cDNAs were sequenced from the distantly related flies Drosophila melanogaster and Drosophila silvestris, and found to be highly conserved except in the central region, which contains at least 21 insertions and deletions. Comparison of fly and human Pez reveals several short conserved motifs in the central region that are likely protein binding sites and/or phosphorylation sites. We also identified novel invertebrate members of the BAS and MEG classes using genome data, and generated an alignment of vertebrate and invertebrate FERM domains of each class. 'Specialized' residues were identified that are conserved only within a given class of PTPs. These residues highlight surface regions that may bind class-specific ligands; for PEZ, these residues cluster on and near FERM subdomain F1. Finally, the PTP domain of fly Pez was modeled based on known PTP tertiary structures, and we conclude that Pez is likely a functional phosphatase despite some unusual features of the active site cleft sequences. Biochemical confirmation of this hypothesis and genetic analysis of Pez are currently underway.

2-Arachidonoylglycerol and anandamide oppositely modulate norepinephrine release from the rat heart sympathetic nerves

Anandamide (10(-7) and 10(-6) M) as well as a synthetic cannabinoid HU210 (10(-8) to 10(-6) M) suppressed the norepinephrine release evoked by perivascular nerve stimulation (PNS) of the rat heart Langendorff's preparation. The effects of HU210 and the lower dose of anandamide were completely blocked by the cannabinoid CB1-receptor antagonist AM251, while that of anandamide at 10(-6) M was partly mediated by arachidonate-derived metabolites. 2-Arachidonoylglycerol (2-AG), at 10(-6) M in the presence of DFP and indomethacin, increased PNS-evoked norepinephrine release, which was completely blocked by AM251. The present results suggest that the two endocannabinoids may oppositely participate in the CB1-receptor-mediated modulation of sympathetic norepinephrine release.

Mutations in the novel membrane protein spinster interfere with programmed cell death and cause neural degeneration in Drosophila melanogaster

Mutations in the spin gene are characterized by an extraordinarily strong rejection behavior of female flies in response to male courtship. They are also accompanied by decreases in the viability, adult life span, and oviposition rate of the flies. In spin mutants, some oocytes and adult neural cells undergo degeneration, which is preceded by reductions in programmed cell death of nurse cells in ovaries and of neurons in the pupal nervous system, respectively. The central nervous system (CNS) of spin mutant flies accumulates autofluorescent lipopigments with characteristics similar to those of lipofuscin. The spin locus generates at least five different transcripts, with only two of these being able to rescue the spin behavioral phenotype; each encodes a protein with multiple membrane-spanning domains that are expressed in both the surface glial cells in the CNS and the follicle cells in the ovaries. Orthologs of the spin gene have also been identified in a number of species from nematodes to humans. Analysis of the spin mutant will give us new insights into neurodegenerative diseases and aging.

Thalamotomy caused by cardioversion in a patient treated with deep brain stimulation

Deep brain stimulation (DBS) has been applied mainly for the treatment of intractable pain and involuntary movement disorders. Based on the rising numbers of patients undergoing DBS therapy, the possibility of emergent application of cardioversion for the treatment of occasional severe arrhythmia in DBS patients has also increased. However, there has been insufficient discussion about cardioversion in DBS patients. We employed a radiofrequency receiver that transmits to the brain impulses provided by an external generator through an antenna applied to the skin in front of the receiver. We experienced a patient who displayed almost complete cessation of his action tremor with thalamic stimulation. He also developed central dysesthetic pain and showed complete disappearance of his action tremor, even without stimulation, following successful application of cardioversion. It is considered that slight changes in the high-voltage electrical current or high-voltage electrical current spread induced central dysesthetic pain and almost identical effects to thalamotomy. We report for the first time a case of thalamotomy induced by cardioversion in a DBS patient. Clearly, we need to bear in mind that cardioversion has the capability to cause brain lesions in DBS patients with a radiofrequency receiver implanted subcutaneously at the anterior chest wall.

KT3-671, an angiotensin AT1 receptor antagonist, attenuates vascular but not cardiac responses to sympathetic nerve stimulation in pithed rats

Effects of KT3-671 on vascular and cardiac sympathetic neurotransmission were investigated in pithed rats. The pressor response to spinal stimulation (5 Hz) of the pithed rat without the adrenals was approximately 75% of that with the adrenals. Guanethidine (8 mg/kg, i.v.) decreased by about 76% the pressor response to sympathetic stimulation in the pithed rat with intact adrenals and the guanethidine-resistant response was almost completely abolished by bilateral adrenalectomy. Therefore, the following experiments were done using the pithed rat without the adrenals. KT3-671 (1-10 mg/kg, i.v.) as well as losartan (1-10 mg/kg, i.v.) inhibited dose-dependently the pressor response to sympathetic stimulation. KT3-671 was approximately four times more potent than losartan in inhibiting the pressor response. The two angiotensin II subtype 1 receptor antagonists (10 mg/kg, i.v.) did not affect the pressor response to exogenously administered norepinephrine. Neither KT3-671 nor losartan influenced the tachycardia induced by spinal stimulation and isoprenaline. Intravenous infusion of angiotensin II (100 ng/kg/min) did not affect both pressor and tachycardic responses to sympathetic stimulation. In conclusion, KT3-671 as well as losartan inhibits vascular but not cardiac sympathetic neurotransmission of the pithed rats, which may contribute to its overall antihypertensive efficacy.

Effect of midodrine on chlorpromazine-induced orthostatic hypotension in rabbits: comparison with amezinium, etilefrine and droxidopa

Orthostatic hypotension was produced in urethane-anesthetized rabbit by a combination of chlorpromazine (0.1 mg/kg, i.v.) and 45 degrees head-up tilt. The effect of midodrine (1 and 3 mg/kg, i.d.) was investigated in comparison with amezinium (10 and 30 mg/kg, i.d.), etilefrine (10 and 30 mg/kg, i.d.) and droxidopa (30 and 100 mg/kg, i.d.). The higher doses of each drug significantly mitigated the chlorpromazine-induced orthostatic hypotension, while none of the lower doses caused a significant effect. The effect of midodrine developed most rapidly; a significant effect was observed 25 min after administration. The order of onset time was midodrine < etilefrine < amezinium < droxidopa. The effect of droxidopa was significant only at 130 to 160 min after administration. The amplitude of effect was in the following order; midodrine = droxidopa > or = etilefrine > amezinium. Midodrine (3 mg/kg, i.d.) mitigated orthostatic hypotension induced by prazosin (0.1 mg/kg, i.v.), but not by pentolinium (0.6 mg/kg, i.v.). It is suggested that midodrine competes with chlorpromazine at alpha1-adrenoceptors and subsequently recovers reflex vasoconstriction. Midodrine may be useful to protect patients with impaired baroreflex activity from accidental orthostatic hypotension during treatment with neuroleptics.

Genomic organisation of the neural sex determination gene fruitless (fru) in the Hawaiian species Drosophila silvestris and the conservation of the fru BTB protein-protein-binding domain throughout evolution

We report the cloning and sequencing of the fru gene from the Hawaiian picture-wing species Drosophila silvestris. The fru gene has seven exons spanning 15-kb encoding two transcripts with ORFs of 841 and 695 amino acids. The protein encoded by the fruA transcript is well conserved with the D. melanogaster type A protein, particularly the BTB protein-protein-binding domain, which is encoded by exons I and II and is 100% conserved. The peptide encoded by exon III has several sequence differences but these are confined mostly to regions of repetitive sequence and exons IV to VI are well conserved. The peptide encoded by exon VII is semi-conserved for the 5' end and 100% conserved for the Zinc finger domains; the rest of the peptide is virtually unconserved. The FRUA protein has a BTB domain and two zinc finger domains whereas the FRUC protein only has the BTB domain. The genomic DNA sequence encoding the BTB domain of the fru gene has been cloned from 21 species of Diptera. The protein-coding sequence is highly conserved and the amino acid sequence is identical except for two changes in the Tephritidae. The intron sequences are completely unconserved except between very closely related species such as the Hawaiian Drosophila. The phylogeny produced using the BTB exon sequences suggests that the most closely related mainland Drosophila species to the Hawaiian clade is D. moriwakii of the melanica species group. The phylogeny also shows that the Scaptomyza are closely related to the Hawaiian Drosophila so supporting a Hawaiian origin for the Scaptomyza. The genus Zaprionus is placed in the subgenus Drosophila closely related to D. immigrans along with the genera Samoaia and Liodrosophila.

Genomic organisation and characterisation of the neural sex-determination gene fruitless (fru) in the Hawaiian species Drosophila heteroneura

There are several mechanisms for the determination of sex. Sexual behaviour is part of the sex-determination cascade, and in Drosophila melanogaster male courtship is controlled in part by the fruitless gene. As part of a study of sexual behaviour in Hawaiian Drosophila, we have cloned the neural sex-determination gene fru from the Hawaiian picture-wing species Drosophila heteroneura. The fru gene has at least seven exons covering a region of 18kb and encodes three transcripts, fruA, fruB and fruC. Each transcript encodes a single ORF of 841, 678 and 691aa, respectively. The FRUA and FRUB proteins have a BTB protein-protein-binding domain and two zinc finger-like domains and are well conserved with the D. melanogaster proteins. The FRUC protein has a BTB domain but no zinc finger-like domains. The fru gene is expressed in 1-7 day old adult males as a 5.1kb transcript. This transcript is not seen in adult females, so the fru gene has a different pattern of sex-differential expression in the Hawaiian Drosophila compared with D. melanogaster.

Acidosis enhances translocation of protein kinase C but not Ca(2+)/calmodulin-dependent protein kinase II to cell membranes during complete cerebral ischemia

Systemic hyperglycemia and hypercapnia severely aggravate ischemic brain damage when instituted prior to cerebral ischemia. An aberrant cell signaling following ischemia has been proposed to be involved in ischemic cell death, affecting protein kinase C (PKC) and the calcium calmodulin kinase II (CaMKII). Using a cardiac arrest model of global brain ischemia of 10 min duration, we investigated the effect of hyperglycemia (20 mM) and hypercapnia (pCO(2) 300 mmHg) on the subcellular redistribution of PKC (alpha, beta, gamma) and CaMKII to synaptic membranes and to the microsomes, as well as the effect on PKC activity. We confirmed the marked translocation of PKC and CaMKII to cell membranes induced by ischemia, concomitantly with a decrease in the PKC activity in both the membrane fraction and cytosol. Hyperglycemia and hypercapnia markedly enhanced the translocation of PKC-gamma to cell membranes while other PKC isoforms were less affected. There was no effect of acidosis on PKC activity, or on translocation of CaMKII to cell membranes. Our data strongly suggest that the enhanced translocation of PKC to cell membranes induced by hyperglycemia and hypercapnia may contribute to the detrimental effect of tissue acidosis on the outcome following ischemia.

A case of adenocarcinoma with clear cell carcinoma of the bladder

A case of adenocarcinoma with clear cell carcinoma of the bladder in a 65-year-old male is reported. Our patient had a walnut-sized nodular tumor located on the anterior wall of the bladder. The patient underwent radical cystoprostatectomy with urethral hemi-Koch pouch. Histopathological examination revealed a lesion composed of poorly-differentiated adenocarcinoma and clear cell carcinoma with diffuse sheet patterns of cells with abundant, clear cytoplasm. The patient died of general metastasis 18 months after operation. To our knowledge this is the first case of adenocarcinoma with clear cell carcinoma arising from the anterior wall of the bladder in a male.

Intraoperative electrooculographic monitoring of oculomotor nerve function during skull base surgery. Technical note

Intraoperative monitoring techniques for protecting the integrity of the oculomotor nerves during skull base surgery have been reported by several investigators, all of which involved the use of electromyographic responses to extraocular muscles. However, these techniques have not yet become popular because of the complexity of the procedures. The authors report an extremely simple and far more reliable technique in which electrooculographic (EOG) monitoring is used. The oculomotor nerves were stimulated with a monopolar electrode during skull base exposure. The polarity of the EOG responses recorded with surface electrodes placed on the skin around the eyeball yielded precise information concerning the location and function of the oculomotor and abducent nerves. In addition, with the aid of continuous EOG monitoring that detected transient changes in the background waves, surgical procedures that might impinge on oculomotor nerve function could be avoided. The present technique has been used in eight patients with skull base tumors and with it, the authors have achieved excellent results.

A rabbit model for evaluation of chlorpromazine-induced orthostatic hypotension

The present study was conducted to develop an experimental model for evaluation of chlorpromazine-induced orthostatic hypotension in rabbits. In addition, the alpha-adrenoceptor blocking effect of chlorpromazine was investigated in isolated rabbit aorta and saphenous vein in comparison with prazosin. Chlorpromazine (0.1 and 1 mg/kg, i.v.) potentiated significantly a decrease in mean blood pressure at 1 min after the onset of head-up tilt in rabbits anesthetized with urethane alone, urethane+alpha-chloralose or nitrous oxide alone, but not in conscious and morphine+urethane+alpha-chloralose-anesthetized rabbits. There was a negative correlation (r=-0.986, p<0.01) between the extent of chlorpromazine-induced orthostatic hypotension and the amplitude of tilt-induced reflex tachycardia before chlorpromazine treatment. Both prazosin and pentolinium elicited orthostatic hypotension under all four anesthetic conditions. The pA2 value for chlorpromazine to antagonize norepinephrine-induced contraction in aorta was significantly larger than that in saphenous vein, whereas prazosin blocked aortic and venous contractions to a similar extent. These results suggest that a rabbit under an anesthesia which impairs tilt-induced reflex tachycardia may be useful for evaluation of orthostatic hypotension by chlorpromazine. The relatively low potential of chlorpromazine to produce orthostatic hypotension may be partly due to its weak venodilating action.

[Clinical study on prostate cancer initially presenting with disseminated intravascular coagulation syndrome]

We experienced five patients with prostate cancer with disseminated intravascular coagulation syndrome (DIC) at the first presentation at Gunma University Hospital and affiliated institutions between 1991 and 1997. Their average age was 68 years, average DIC score at the first presentation was 10 and prostate specific antigen (PSA) level was more than 700 ng/ml. All of them had multiple bone metastases. The therapy for DIC and hormonal therapy for prostate cancer were simultaneously started at the first presentation before prostate needle biopsy, but all patients died. The average number of days from the start of DIC to death was 685 days. The patients initially showed a good response to therapy, but their conditions soon aggravated. The prognosis was extremely poor, but some proper therapies lead to the prognosis which was equal to that of prostate cancer in Stage D2 without DIC.

Multiple choroid plexus papillomas of the lateral ventricle distinct from villous hypertrophy. Case report

Except for villous hypertrophy of the choroid plexus that may not be true tumors, multiple choroid plexus papillomas are extremely rare. The authors report a case involving multiple choroid plexus papillomas that were distinct from villous hypertrophy. These lesions were localized, one in the atrium of the right lateral ventricle and the other in the inferior horn of the left lateral ventricle. A review of the literature revealed that this case represented the first reported case of true multiple choroid plexus papillomas documented by findings on magnetic resonance imaging.

Significance of measurement of prostate specific antigen (PSA) in familial prostate cancer lines

The concentration of prostate specific antigen (PSA) in serum was measured in 20 brothers or sons in 10 families in which the father and son or brothers had prostate cancer using the E test TOSOH IIPA. The patients were between 32 and 70 years old with a mean age of 48.2 years. The PSA value was between 0.4 and 19.5 ng/ml with a mean value of 3.4 ng/ml. Five patients (25%) had PSA values exceeding the cut-off value of 4.0 ng/ml. After obtaining their consent, systematic prostate needle biopsy by transrectal ultrasonography was performed on 3 patients (15%). Prostate cancer was detected in all of them. Among them 2 patients were brothers, and since the other two brothers already had prostate cancer, all four brothers were confirmed to have prostate cancer. This is the first report of a familial prostate cancer in four brothers in Japan. In the western countries where the incidence of prostate cancer is higher than that in Japan, studies have been performed on the risk factors. Family history is one of the most important risk factors. In Japan, the incidence of prostate cancer is increasing rapidly. Moreover, patients with a prostate cancer family history are expected to increase. In such cases, prostate cancer screening should be performed aggressively from a young age.

[The mass screening for prostate cancer and the age eligibility. Gunma Urological Oncology Study Group]

BACKGROUND

The age eligibility for the mass screening (MS) for prostate cancer was investigated.

METHODS AND MATERIALS

This study was performed in subjects examined by MS from 1981 to 1994 in Gunma Prefecture, Japan. MS was performed by digital rectal examination (DRE) and prostatic acid phosphatase from 1981 to 1991, and by DRE, transrectal ultrasonography and prostate specific antigen from 1992 to 1994.

RESULTS

It was demonstrated that the prostate cancer detection rate was affected by the ratio of subjects newly and previously examined, the age distribution in the group examined and the diagnostic modality. It was also demonstrated that the detection rate of early stage prostate cancer was also affected by the age distribution and the diagnostic modality. The effective detection rate was determined on the assumption that the purpose of MS is the detection of the subjects who have the indication for the radical prostatectomy, and the effective detection rate was calculated in the range from 50 to 69 years for age eligibility, and B and C for clinical stage. It was estimated that effective detection rate was 0.37 to 0.61%. They were higher than the detection rate of MS for other organ cancers.

CONCLUSION

The eligibility is 50 to 69 years. If subjects in the range of 70 to 74 are included in this project, it is necessary to make an effort practice a subject-education about the prostate cancer natural history and the radical prostatectomy indication.

Persistent translocation and inhibition of Ca2+/calmodulin-dependent protein kinase II in the crude synaptosomal fraction of the vulnerable hippocampus following hypoglycemia

Alterations in the levels and activity of Ca2+/calmodulin-dependent protein kinase II (CaM-kinase II) were studied in the rat hippocampus during and after insulin-induced hypoglycemic coma. A permanent loss of CaM-kinase II immunohistostaining in the neuronal layer begins at 10 min of isoelectricity in the tip of the dentate gyrus and at 30-min isoelectricity in the CA1 region. The reduction in immunohistostaining in the neurites is less pronounced. Immunoreactivity of CaM-kinase II on western blots increases in the crude synaptosomal fractions and decreases in cytosolic fraction, indicative of a translocation of CaM-kinase II. The translocation persists for at least 1 day of recovery after 30 min of isoelectricity in the vulnerable hippocampus (dorsomedial hippocampus) but not in the resistant hippocampus (dorsolateral hippocampus). Calmodulin binding to western blots shows changes similar to the immunoblots. Ca2+/calmodulin-dependent activity of CaM-kinase II in the crude synaptosomal fraction is elevated immediately before isoelectricity and is then inhibited during and after 30 min of isoelectricity, despite the increase of CaM-kinase II immunoreactivity. This was seen in the vulnerable hippocampus. The data indicate that stimulus of translocation and inhibition of CaM-kinase II persist during the recovery phase, preceding neuronal degeneration in the vulnerable hippocampus. This may be of significance for hypoglycemia-induced neuronal death.

Changes in the tyrosine phosphorylation of mitogen-activated protein kinase in the rat hippocampus during and following severe hypoglycemia

The changes in the levels of tyrosine-phosphorylated proteins in the cytosolic fraction of the rat hippocampus subjected to severe hypoglycemia were analyzed. A marked increase in tyrosine phosphorylation of a 43-kDa protein was observed at 30 min of isoelectric EEG and 30 min and 1 h of recovery. Immunostaining of the same blot with antibody against mitogen-activated protein (MAP) kinase demonstrated a double band of approximately 42 and 43 kDa. The increased tyrosine phosphorylation of MAP kinase during hypoglycemic coma and the early recovery period suggests that MAP kinase may be involved in neuronal degeneration and repair.

Influence of transient global cerebral ischemia on the facilitatory modulation of the vagal baroreflex in dogs

The influence of 5-min global cerebral ischemia on the facilitatory modulation of the vagal baroreflex through central alpha 2-adrenoceptors or by the electrical stimulation of the septum was investigated in anesthetized dogs. Reflex bradycardia was produced by a bolus injection of phenylephrine at a dose which produces about a 25-mmHg increase in mean blood pressure. The ischemia was produced by the occlusion of the brachiocephalic and the left subclavian arteries with preceding ligation of the intercostal arteries. Clonidine at 10 micrograms, administered intracisternally, decreased the blood pressure and heart rate and facilitated the vagal reflex bradycardia. During the reperfusion period following ischemia, however, clonidine failed to affect the reflex bradycardia. Electrical stimulation of the septal region facilitated the reflex bradycardia without marked influences on the basal blood pressure and heart rate. The facilitatory effect was dependent on the frequency (10 to 75 Hz) and amplitude (3 to 15 V) of stimulation and was not observed after vagotomy or ischemic insult. These results suggest that 5-min global cerebral ischemia may produce the dysfunction of the neurons which are closely related to the baroreflex loop and receive the facilitatory modulation through alpha 2-adrenoceptors and/or from the forebrain structures, leading to the dysfunction of the vagal baroreflex.

[Age-related changes in the size and shape of the prostate observed by transrectal ultrasonography]

To elucidate the change with aging in prostatic morphology, 447 cases without acute diseases and prostate cancer of the first visit from January 1988 to December 1990 were examined by transrectal ultrasonography. Total weight of the prostate, area of maximum section, lateral and anteroposterior diameter on the maximum section and supero-inferior diameter were evaluated. The total weight of the prostate was not found to be correlated with aging. The total weight of the prostate showed a high variation with aging. Prostate growth with more than 30 g was greater in the fifties and increased gradually thereafter. Similar findings were observed for antero-posterior diameter on the maximum section and supero-inferior diameter. With aging, the total weight of the prostate in 20-30% of the patients showed an increase while in 30-40% of the patients, no increase. The total weight of the prostate increased in the fifties with subsequent gradual increase in the sixties. According to prostate shape, antero-posterior diameter on the maximum section and supero-inferior diameter was related to the weight of the prostate.

Blockade of alpha 2-adrenoceptors protects the vagal baroreflex system from transient global cerebral ischemia in dogs

Ifenprodil, phentolamine, yohimbine or idazoxan, 1 mg/kg i.v., administered 5 min prior to 5-min global cerebral ischemia, completely prevented the post-ischemic dysfunction of the vagal baroreflex in anesthetized dogs. Idazoxan, 0.1 mg/kg i.v., was cerebroprotective against mild ischemia, but ineffective against severe ischemia. The post-ischemic administration of idazoxan, 1 mg/kg i.v., failed to restore the damaged vagal baroreflex. These results suggest that blockade of alpha 2-adrenoceptors during ischemia and the early reperfusion period may protect the vagal component of baroreflex from cerebral ischemia.

Protection by nicorandil against the dysfunction of the central vagal baroreflex system following transient global cerebral ischaemia in dogs

1. A possible cerebroprotective effect of nicorandil was investigated in a canine model of 5 min global cerebral ischaemia, and compared with protective effects of nitroglycerin and nicardipine. 2. Cerebral ischaemia was produced by occlusion of the left subclavian and the brachiocephalic arteries with preceding ligation of the intercostal arteries. The decrease in baroreflex sensitivity (BRS), measured by phenylephrine-induced reflex bradycardia, was used to assess the cerebroprotective effect. 3. Nicorandil (10 or 30 micrograms kg-1 min-1, i.v.), nitroglycerin (3 micrograms kg-1 min-1, i.v.) or nicardipine (0.3 micrograms kg-1 min-1, i.v.) were infused for 60 min just before ischaemia. Nitroglycerin and nicardipine decreased mean arterial blood pressure to an extent similar to that induced by the lower dose of nicorandil. Blood flow in the dorsal medulla oblongata was increased by nicorandil and nicardipine, but not by nitroglycerin. 4. Nicorandil at both doses and nitroglycerin prevented the post-ischaemic decrease in BRS. In these cases, bilateral vagotomy during the reperfusion period decreased BRS, indicating that the vagal component of BRS was protected from ischaemia. On the other hand, nicardipine failed to exert a cerebroprotective effect. 5. The present study suggests that nicorandil may possess a direct cerebroprotective effect and that its property as a nitrate might, at least in part, be important for the observed cerebral protection.

[Clinical evaluation of Augpenin (clavulanic acid-ticarcillin) in urinary tract infections: especially against beta-lactamase producing strains]

Augpenin contains ticarcillin (TIPC) and clavulanic acid (CVA), at a ratio of 15:1. The beta-lactamase inhibitor, CVA, has been added to protect the TIPC from inactivation by beta-lactamase. To investigate the drug efficacy and safety against urinary tract infections (UTI), Augpenin was administered to 33 patients with chronic complicated UTI and 7 patients with acute pyelonephritis. Thirty two cases were evaluable by the UTI criteria. Excellent results were obtained in 6 of the cases of acute pyelonephritis, and moderate results in 1 case, with an overall effectiveness rate of 100%. Excellent results were obtained in 14 of the cases of chronic complicated UTI, moderate results in 9 cases, and poor results in 2 cases, with an overall effectiveness rate of 92%. No adverse reactions were noted, but a transient elevation of glutamic oxaloacetic transaminase and glutamic pyruvic transaminase levels was observed in 2 cases.

[The clinical significance of carbohydrate antigen 19-9 (CA19-9) in transitional cell cancer of urinary tract]

For the purpose of evaluating the utility of CA19-9 determination in transitional cell cancer (TCC) of the urinary tract, its serum value, tissue level and, immunohistochemical study, and follow up study, with high serum value were examined in 43 cases with TCC and 13 cases of control. 1. Serum values were 19.1 U/ml in the control group and 198 U/ml in the tumor group. Though those of tumor were higher than those of the control group, there is no statistical difference between both groups. The cases with abnormally high value were observed in 13.7% of the control group, 13.8% of the bladder cancer, and 57.1% of the upper urinary tract cancer. 2. Tissue levels were 816 U/g wet tissue in the control group and 13,000 U/g wet tissue in the tumor group, showing a significantly higher value (p < 0.01) in the tumor group, statistically. 3. Immunohistochemical study were positive in 4.0% of the control group and 88.4% of the tumor group. 4. There is a significant correlation between serum values and tissue levels (p < 0.05, r = 0.483). 5. The serum values did not correlated with the staining property, tumor size, grade, and stage. 6. The tissue levels correlated with the tumor size, but did not correlate with the staining property, grade, and stage. 7. In the follow-up study of cases with high value, those, who had not attained postoperative normalization, died of recurrent carcinoma. In cases showing an elevation despite postoperative normalization, too, all showed recurrence. Only those, whose value were normalized and remained at the normal range, are living without metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Protection by halothane of the vagal baroreflex system from transient global cerebral ischemia in dogs

A possible cerebroprotective effect of halothane was investigated in a canine model of 5-min global cerebral ischemia. In pentobarbital-anesthetized dogs, additional inhalation of 0.5 to 1% halothane prior to ischemia prevented the post-ischemic dysfunction of the vagal component of reflex bradycardia. In contrast, pretreatment with thiopental at 10 mg/kg, i.v. failed to prevent it. The influence of ischemia in the absence of anesthetics was similar to that under barbiturate anesthesia. The results suggest that halothane, but not barbiturate, may actively protect the vagal baroreflex system from ischemia.

MK-801 prevents the post-ischemic cerebral hypoperfusion, but not the dysfunction of the vagal baroreflex in dogs

Pretreatment with MK-801, a non-competitive N-methyl-D-aspartate (NMDA) antagonist, failed to protect the vagal component of reflex bradycardia from 5-min global cerebral ischemia in dogs under pentobarbital anesthesia. On the other hand, MK-801 completely prevented the development of the post-ischemic cerebral hypoperfusion without affecting the cerebral blood flow in sham-operated animals. The results suggest that NMDA receptors may participate in the development of the secondary disturbance of the cerebral circulation, but are not involved in the post-ischemic dysfunction of the baroreflex system.

Difference between halothane and barbiturate anesthesia in the influence of cerebral ischemia on the vagal baroreflex in dogs

In halothane-anesthetized dogs, a decrease in baroreflex sensitivity (BRS) of approximately 20% was observed during the reperfusion period following 5-min global cerebral ischemia. When compared with our previous study on animals under pentobarbital anesthesia, the extent of the decrease in BRS was smaller and apparently more severe ischemia was necessary to damage the vagal component of the baroreflex. Substitution of halothane with pentobarbital during the reperfusion period failed to affect either BRS or the ratio of the vagal component. In another group, pre- and post-ischemic measurements of BRS was performed under halothane anesthesia, but the ischemic insult was given under thiopental anesthesia. In these animals, the extent of decrease in BRS (about 50%) was greater than that in animals subjected to ischemia under halothane anesthesia. The present results suggest that the anesthetics used during the ischemic insult may affect the extent of post-ischemic dysfunction of the baroreflex. The vagal component of the baroreflex may be more resistant to ischemia under halothane anesthesia than under barbiturate anesthesia.