Effect of six steroidal saponins isolated from anemarrhenae rhizoma on platelet aggregation and hemolysis in human blood

Six steroidal saponins were isolated from Anemarrhena asphodeloides Bunge (Liliaceae), a traditional chinese medicine, and named anemarrhenasaponin I (An-I), anemarrhenasaponin Ia (An-Ia), timosaponin B-I (TB-I), timosaponin B-II (TB-II), timosaponin B-III (TB-III), and timosaponin A-III (TA-III). The effects of these six compounds on platelet aggregation and hemolysis in human blood were studied. All these compounds provoked remarkable inhibiting effect on platelet aggregation, and activated partial thromboplastin times (APTT) are sensitive to the presence of these six compounds. Using an in vitro system, APTT was delayed with the increment of the concentrations of these six compounds. In these six compounds, only timosaponin A-III appeared a strong effect on hemolysis, and anemarrhenasaponin Ia had a slight effect on hemolysis, other had no effect on hemolysis. These results suggested that these steroidal saponins isolated from Anemarrhena asphodeloides Bunge (Liliaceae) might be used as a novel antithrombotic therapeutic agents in post-myocardial infarction.

Effects of propofol and remifentanil on phrenic nerve activity and nociceptive cardiovascular responses in rabbits

BACKGROUND

The effects of propofol, remifentanil, and their combination on phrenic nerve activity (PNA), resting heart rate (HR), mean arterial pressure (MAP), and nociceptive cardiovascular responses were studied in rabbits.

METHODS

Basal anesthesia and constant blood gas tensions were maintained with alpha-chloralose and mechanical ventilation. PNA, HR, MAP, and maximum changes in HR and MAP (deltaHR, deltaMAP) evoked by electrical nerve stimulation of tibial nerves were recorded. The comparative effects were observed for propofol at infusion rates from 0.05 to 3.2 mg x kg(-1) x min(-1) (group I) and remifentanil from 0.0125 to 12.8 microg x kg(-1) x min(-1) alone (group II), and during constant infusions of propofol at rates of 0.1 and 0.8 mg x kg(-1) x min(-1) (groups III and IV, respectively). Finally, the effect of remifentanil on propofol blood levels was observed (group V).

RESULTS

The infusion rates for 50% depression (ED50) of PNA, deltaHR, and deltaMAP were 0.41, 1.32, and 1.58 mg x kg-(1) x min(-1) for propofol, and 0.115, 0.125, and 1.090 microg x kg(-1) x min(-1) for remifentanil, respectively. The ratios for the ED50 values of deltaHR and deltaMAP to PNA were 3.2 and 3.9 for propofol, and 1.1 and 9.5 for remifentanil, respectively. Analysis of the expected and observed responses and isobologrms showed that although their combined effects on PNA, resting HR, and MAP, and deltaMAP were synergistic for deltaHR, they were merely additive. Remifentanil had no effect on propofol blood levels.

CONCLUSION

PNA was abolished by propofol and remifentanil, alone and in combination, before significant depression of nociceptive pressor responses occurred. Their combined effects on PNA, HR, MAP, and deltaMAP are greater than additive, ie., synergistic. Unlike propofol, remifentanil obtunded pressor responses more than the resting circulation.

[Effects of ligustrazine on plasma platelet aggregation rate, thromboxane B2, 6-keto-prostaglandin F1 alpha and von Willebrand's factor in patients with acute onset of cor pulmonale]

OBJECTIVE

To study the effect on large dose of Ligustrazine on the function of platelet and endothelial cells of patients with acute onset of cor pulmonale.

METHODS

Platelet aggregation rate (PAR), thromboxane B2 (TXB2), 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha), von Willebrand's factor (vWF), PaO2 and PaCO2 were assayed in 30 patients with acute onset of cor pulmonale and 26 cases of control before and after treatment of large dose of Ligustrazine.

RESULTS

PAR, vWF, TXB2, TXB2/6-keto-PGF1 alpha and PaCO2 decreased (P < 0.05, P < 0.01), and 6-keto-PGF1 alpha, PaO2, SaO2 increased (P < 0.01) after treatment of Ligustrazine, and only PaCO2 decreased in control.

CONCLUSION

Ligustrazine had the function of antiplatelet and protecting the endothelial cells. Large dose (800 mg/d) had no side-effects.

Preparation of alpha-emitting 213Bi-labeled antibody constructs for clinical use

Preclinical evaluation of alpha particle-emitting 213Bi-labeled antibody constructs have demonstrated the specificity and potency of these agents in a variety of cancer systems. The transition of a 213Bi-radiolabeled antibody from a preclinical construct to a clinical drug represented a difficult task that involved development of reliable and validated methods to provide multiple MBq quantities of a pure, immunoreactive agent that met pharmaceutical standards to treat patients.

METHODS

The methods used for the preparation of (213Bi)CHX-A-diethylenetriamine pentaacetic acid (DTPA)-HuM195, an alpha particle-emitting anti-CD33 antibody construct for therapy of myeloid leukemias, is used as a specific example. This article describes methods for reagent purification, drug labeling, radioprotection and chromatographic purification. Quality of the drug is evaluated using radiochemical incorporation and purity assays with instant thin-layer chromatography (ITLC) and high-performance liquid chromatography (HPLC), determination of cell-based antibody total immunereactivity, small animal safety, pyrogen level, sterility and radionuclidic purity.

RESULTS

Sixty-seven doses were prepared. Individual doses ranged from 148 to 814 MBq. Specific activities ranged from 329 to 766 MBq/mg. The radiolabeling efficiency (median +/- SD) of CHX-A-DTPA-HuM195 with 213Bi was 81% +/- 9% (n = 67) after 9 min. The construct was purified by size-exclusion chromatography and was found to be 99% +/- 2% pure (n = 67) by either ITLC or HPLC methods. The immunoreactivity of (213Bi)CHX-A-DTPA-HuM195 was 89% +/- 9% (n = 44) and was independent of the specific activity. The formulated pharmaceutical was found to contain < or =4 +/- 1 EU/mL pyrogens (n = 66); all samples examined were sterile. An 225Ac radionuclidic impurity was present at a level of 0.04 +/- 0.03 x 10(-6)/mL (n = 10) in a product volume of 7.4 +/- 0.5 mL (n = 67). Each of the 67 doses was injected intravenously into patients without complication as part of a phase I clinical trial.

CONCLUSION

These data show that 213Bi-labeled antibody constructs can be prepared and administered safely to humans at a wide range of therapeutic levels.

Arterial to inspired partial pressure ratio of halothane, isoflurane, sevoflurane and desflurane in rats

The inspired partial pressure of an anaesthetic is often used as an index of arterial partial pressure in small animal experiments. We have investigated the influence of anaesthetic solubility on the ratio of arterial to inspired partial pressure in 24 rats, allocated randomly to receive halothane, isoflurane or desflurane at four different inspired concentrations. The arterial partial pressure of the volatile agent was measured by two-stage headspace analysis using a gas chromatograph calibrated with the same gas used to calibrate the Datex Capnomac that measured the inspired concentration. Mean values of arterial to inspired ratio at the lowest concentrations were 0.60 (95% confidence intervals 0.50, 0.71) for 0.8% halothane, 0.54 (0.38, 0.69) for 0.8% isoflurane, 0.72 (0.59, 0.86) for 1.5% sevoflurane and 0.71 (0.54, 0.87) for 4% desflurane. Analysis of variance showed a significant effect of anaesthetic agent (P = 0.008) on the arterial to inspired ratio. Thus volatile anaesthetic agents do not demonstrate a fixed arterial to inspired ratio in rats.

Serotonergic responses of the siphons and adjacent mantle tissue of the zebra mussel, Dreissena polymorpha

Bivalve siphons have important functional roles in nutritional physiology, defense, and reproductive mechanisms, yet little is known about their neuromuscular control. In the present study, tension measurements and video observations of siphons and adjacent mantle tissue were used to investigate responses to serotonin (5-HT). 5-HT caused relaxation at 10(-6) M and 10(-5) M, contraction or biphasic responses at 10(-4) M and 10(-3) M, and siphon opening at 10(-4) M and 10(-3) M. Responses were slow and lasted 5-10 min after much shorter (20 s) applications of 5-HT. The relaxation phase was enhanced in high potassium medium. Contractile responses could be mimicked by alpha-1-methyl-5-HT and 2-methyl-5-HT but not by 8-OH-DPAT. The responses were not affected by methiothepin, TFMPP, 1-(1-naphthyl)piperazine, metergoline, NAN-190, mianserin, cyproheptadine, and ketanserin. The pharmacology of the 5-HT receptor(s) mediating these siphon/mantle responses is, therefore, different from previously described 5-HT receptors involved in spawning. The siphon/mantle contains previously undescribed longitudinal muscle fibers in the mantle and circular muscle fibers around the siphons. Serotonergic innervation of the siphon margins and mantle tissue was observed by immunohistology. The presence of 5-HT in the siphon/mantle tissue and the responsiveness of these preparations to 5-HT suggest that 5-HT may be a physiological regulator of mantle and siphon movements in the zebra mussel.

[Synthesis of the new reagent N-hexyl-N'-(sodium aminobenzenesulfonate) thiourea (HXPT) and its spectrophotometric study with Pd2+]

A new reagent N-Hexyl-N'-(sodium aminobenzenesulfonate) thiourea (HXPT) was synthesized. Its structure was also characterized. A new spectrophotometric method of determining Pd2+ was developed based on the new reagent. In the range of pH 5.4-5.8 Pd2+ forms a stable yellow complex with HXPT in the presence of CTMAB,and its apparent molar absorptivity is 2. 21 x 10(5) L x mol(-1) x cm(-1) at the maximum absorption wavelength 296.8 nm. Beer's law is obeyed in the range of 1-7 microg x 25 mL(-1) for Pd2+. This method has been used for the determination of trace Pd2+ in ores and catalyst with satisfactory results.

[Basal cell adenocarcinoma of the salivary gland: a clinicopathologic study of 14 cases]

OBJECTIVE

To study clinicopathologic features and behaviour of the basal cell adenocarcinoma of salivary gland tumor and prognosis of the patients,

METHODS

14 cases with basal cell adenocarcinoma were studied clinicopathologically.

RESULTS

The clinical features were as follows: females more than males; most frequently in the minor salivary glands; 21.4% of cervical lymph node metastasis and 14.3% of distant metastasis; and rather poor prognosis. The histopathologic appearances were similar to those of basal cell adenoma, but with more mitotic figures and infiltrating growth.

CONCLUSION

This tumor was of moderate grade malignancy. It must be treated radically. The elective neck dissection could be considered for the patients with extensive tumors.

Inhibition of intraocular tumor growth by topical application of the angiostatic steroid anecortave acetate

PURPOSE

This study examined the effect of an angiostatic agent on the growth of a highly vascularized intraocular tumor.

METHODS

A murine uveal melanoma cell line (99E1) was transplanted intracamerally into athymic nude BALB/c mice. Mice were treated topically three times per day beginning on the day of tumor transplantation and continuing through day 28. Groups included (a) 1% anecortave acetate, (b) vehicle control, or (c) no treatment. Tumor growth was scored clinically according to the volume of anterior chamber occupied by tumor. Intraocular tumor weights were determined on days 10, 14, 21, and 28. The effect of the test agents on tumor cell proliferation was examined in vitro by [3H]thymidine incorporation.

RESULTS

Tumors grew progressively in untreated mice and mice treated with the vehicle; tumors filled the entire eye by day 20 and frequently perforated the globe by day 21. By contrast, tumors treated with anecortave acetate grew significantly slower (P < 0.025) and did not perforate the eye. On days 21 and 28 the net tumor weight of the AL-3789-treated animals was 40% to 30% of controls (P < 0.05). Tumor inhibition was presumably due to the angiostatic properties of anecortave acetate because the compound did not affect tumor cell proliferation in vitro.

CONCLUSIONS

The topical ocular administration of anecortave acetate restricted the growth of a highly vascularized angiogenic intraocular tumor.

The combined effects of sevoflurane and remifentanil on central respiratory activity and nociceptive cardiovascular responses in anesthetized rabbits

We studied the effects of sevoflurane and remifentanil, alone and in combination, on phrenic nerve activity (PNA), resting heart rate (HR), arterial pressure (MAP), and changes in HR (delta HR) and MAP (delta MAP) evoked by electrical stimulation of tibial nerves in anesthetized rabbits. The 50% effective dose (95% confidence intervals) for the depressant effects of sevoflurane on delta HR, delta MAP, and PNA were 2.3 (1.8%-2.6%), 2.7 (2.3%-2.9%), and 3.4 (3.1%-3.7%), respectively, and for remifentanil were 0.100 (0.050-0.132), 0.850 (0.720-1.450), and 0.090 (0.080-0.145) microgram.kg-1.min-1, which were reduced to 0.046 (0.021-0.065), 0.110 (0.080-0.200), and 0.030 (0.020-0.040) microgram.kg-1.min-1, respectively, by 1% sevoflurane. Depression of evoked cardiovascular responses relative to PNA was greater for sevoflurane and less for remifentanil both alone and in combination with sevoflurane. Sevoflurane acted synergistically with remifentanil on PNA and delta MAP, but not delta HR, for which their combined effect was additive. Coadministration of 1% sevoflurane with the highest infusion rate of remifentanil (1.6 micrograms.kg-1.min-1) used during combined administration reduced resting HR and MAP by 25% (P < 0.05) and 41% (P < 0.05), respectively, which was greater than the predicted reductions of only 14% and 15% if their combined effects had been additive. We conclude that sevoflurane caused a relatively greater depression of nociceptive cardioaccelerator and pressor responses compared with PNA and vice versa for remifentanil. When coadministered, their combined effects on PNA, resting HR, MAP, and delta MAP were synergistic, whereas they were merely additive for delta HR.

IMPLICATIONS

Although sevoflurane caused relatively greater depression of nociceptive cardiovascular responses compared with phrenic nerve activity, remifentanil either alone or combined with sevoflurane caused a much greater depression of phrenic nerve activity than cardio-accelerator and pressor responses. This could imply that, during major surgery using anesthesia combining sevoflurane and remifentanil, spontaneous ventilation is not acceptable, and depression of the resting circulation may be much greater than anticipated.

Specific actions of halothane, isoflurane, and desflurane on sympathetic activity and A delta and C somatosympathetic reflexes recorded in renal nerves in dogs

BACKGROUND

This was a study of the relative effects on directly recorded sympathetic activity of desflurane, isoflurane, and halothane.

METHODS

Renal sympathetic nerve activity (RSNA) was recorded with bipolar electrodes in renal nerves exposed retroperitoneally in anesthetized (alpha-chloralose), paralyzed (succinylcholine), and artificially ventilated dogs. Somatosympathetic responses were evoked by supramaximal electrical stimulation of radial nerves (0.33 Hz, 30 V, 0.5 ms). Spontaneous and evoked activity were rectified, averaged, and integrated to allow quantitative comparison of the effects of 3-12% desflurane, 0.6-2.4% isoflurane, and 0.4-1.6% halothane.

RESULTS

Increasing concentrations of isoflurane progressively depressed mean RSNA, Adelta, and C reflexes by 40% (P < 0.01), 50% (P < 0.01) and 70% (P < 0.001) respectively at 2.4% concentration. Halothane depressed both reflexes equally by approximately 60% (P < 0.01) at 1.6% concentration, without significant depression of spontaneous RSNA. Desflurane increased and subsequently decreased RSNA by 37% (P < 0.02) and 65% (P < 0.001) at concentrations of 6% and 12% respectively, and although somatosympathetic reflexes remained unchanged up to 9%, both were depressed equally by 70% (P < 0.01) at 12% concentration.

CONCLUSION

After equilibration, lower concentrations of desflurane remained excitatory, but, like isoflurane, higher concentrations depressed RSNA. The effect of halothane on RSNA was insignificant. Isoflurane depressed C more than Adelta somatosympathetic reflexes, which is uncorrelated with lipid solubility because desflurane and halothane, which have the highest and lowest minimum alveolar concentration, respectively, depressed both equally.

[Registration and fusion of multimodality medical images]

This paper introduces the present situation of research and methods of multimodality medical images fusion. Some algorithms and relative techniques are given in detail. A summary of the clinical application of multimodality medical images fusion is also presented.

[Sodium arsenite selectively inducing apoptosis of G2 + M phase NB4 cells]

OBJECTIVE

To explore the mechanism of sodium arsenite inducing apoptosis of NB4 cells.

METHODS

The apoptosis of NB4 cells was studied by flow cytometry, DNA gel electrophoresis and Western blot analysis.

RESULTS

1. Sodium arsenite induced apoptosis of NB4 cells while the cells were arrested in G2 + M phase; 2. dUTP-FITC specifically labeled NB4 cells in G2 + M phase after the cells were treated with sodium arsenite; 3. After the treatment the expressions of cyclin A, E, D1, D2 and D3 of the NB4 cells did not change significantly, while the expression of cyclin B1 was up-regulated with prolongation of the treatment; 4. Some of S phase NB4 cells expressed high level cyclin B1 during the early period of treatment (16 h), but most of NB4 cells expressing high level of cyclin B1 were in G2 + M phase.

CONCLUSION

Sodium arsenite selectively induced apoptosis of G2 + M phase NB4 cells, accompanied by upregulation of cyclin B1.

Synthesis and protein kinase C binding activity of benzolactam-V7

Benzolactam-V7 (3a), a simplified analogues of (-)-indolactam-V with twist-form conformation, was synthesized and evaluated as a new protein kinase C modulator. Both 3a and its-7-substituted analogue 3c showed weak binding activity to displace PDBU binding from recombinant PKCalpha.

[Separation of p-aminobenzenearsonic acid and its oxide by ion-pair reversed-phase high performance liquid chromatography]

To study the separation of p-aminobenzenearsonic acid (PABAA) and its oxide, p-aminophenylarsine oxide (PAPAO), both the absorption spectra were scanned at the wavelengths from 200 nm to 380 nm. PABAA had absorption maximum at 254 nm and PAPAO 258 nm. The effects of salt concentration, column temperature, methanol and ion-pair agent concentrations on the capacity factor were investigated. Compounds of high polarity showed almost no retention on reversed-phase column; as the volume fraction of the methanol decreased from 90% to 10%, the retention time of PABAA gradually increased with broad peak, and partially eluted when methanol volume fraction being below 20%. With temperature rising, the retention time of PABAA was decreased. But PABAA capacity factor can be increased by selecting an appropriate salt concentration for the mobile phase. The cetyltrimethyl and tetrabutyl ammonium ions were separately added as ion-pair agents to the mobile phase containing methanol in phosphate buffer of 10 mmol/L, the changes of retention time were observed. The mechanism of retention based on reversed phase ion-pair model is proposed. Besides, the retention behaviour is also influenced by size exclusion in stationary phase as well as polar interactions with residual silanol group on the silica surface.

An 225Ac/213Bi generator system for therapeutic clinical applications: construction and operation

A method for construction and operation of an 225Ac/213Bi generator capable of producing 25-100 mCi of 213Bi suitable for clinical antibody labeling is described. The generator has been designed to have an effective lifetime of several weeks, producing up to six therapeutic doses of radionuclide per day. To date, 57 clinical doses have been prepared and injected into patients using the described 213Bi generator. Factors such as radiation damage, radioprotection, iodide eluate chemistry, radiolabeling chemistry and radionuclide purity are addressed.

Severe neuronal losses with age in the parietal cortex and ventrobasal thalamus of mice transgenic for the human NF-L neurofilament protein

Transgenic mice expressing human light neurofilament protein (NF-L) display early perikaryal accumulations of disarrayed neurofilaments in layers II/III of the parietal cortex and in the ventrobasal complex of thalamus. This cytoskeletal abnormality, reflected by strong NF-L immunoreactivity, is transient in the developing cortex but persists until old age in the thalamus. To investigate whether it leads to neuronal death, the unbiased cell counting method of the dissector was applied to the parietal cortex and the thalamus of normal and transgenic mice at various postnatal (P10, P20, P90) and advanced ages (14-18 months). Similar data were also obtained from the primary visual cortex free of NF-L accumulation. Compared with normal, the total number of neurons in the parietal (but not occipital) cortex of transgenic mice showed little change during the postnatal period, but decreased markedly with old age, particularly in layers II/III. Severe neuronal loss was also documented in the thalamic ventrobasal complex of aged transgenic mice. The delayed neuronal death in the parietal cortex, occurring long after recovery from the NF-L accumulations, was suggestive of a combination of deleterious factors, including the early overproduction of neurofilament protein and subsequent loss of afferent input from the affected somatosensory thalamic nuclei. Furthermore, strong accumulation of lipofuscin in the neurons of aged transgenic mice suggested that oxidative stress partakes in the mechanisms through which NF-L overproduction compromises neuronal viability.

Simultaneous determination of gamma-aminobutyric acid and glutamic acid in the brain of 3-mercaptopropionic acid-treated rats using liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

The measurement of gamma-aminobutyric acid (GABA) and glutamic acid (Glu) in the whole brain and in various regions of the brain in 3-mercaptopropionic acid (3-MPA)-treated rats has been developed using liquid chromatography-mass spectrometry with an atmospheric pressure ionization interface system. The recoveries of these compounds were 94.90+/-4.18% for GABA, 95.60+/-2.86% for Glu after ion-exchange treatment. The detection limits for GABA and Glu were 2.5+/-0.3 microg/ml and 5.0+/-0.8 microg/ml, respectively, when 20 microl sample were injected. GABA concentration in the whole brain decreased gradually to 5 min and reached 63% of normal value after administration of 3-MPA, and the concentration increased gradually thereafter until 60 min. Conversely, the concentration of Glu in the whole brain increased gradually to 10 min and reached 154% of normal value, and after that decreased gradually and reached almost normal level at 60 min after administration of 3-MPA. GABA concentration in various regions of brain decreased to 5 min in all regions after administration of 3-MPA, and reached normal levels at 60 min as in the whole brain. This method was found to be useful for studies of metabolism of GABA and Glu in biological samples.

Benzolactam (BL) enhances sAPP secretion in fibroblasts and in PC12 cells

Activation of protein kinase C is known to favor the alpha-secretase processing of the Alzheimer's disease (AD) amyloid precursor protein (APP), resulting in the generation of non-amyloidogenic soluble APP (sAPP). Consequently, the relative secretion of amyloidogenic Abeta1-40 and Abeta1-42(3) is reduced. This is particularly relevant since fibroblasts and other cells expressing APP and presenilin AD mutations secrete increased amounts of total Abeta and/or increased ratios of Abeta1-42(3)/Abeta1-40. Interestingly, PKC defects have been found in AD brain alpha and beta isoforms) and in fibroblasts (alpha isoform) from AD patients. Here, we use a novel PKC activator (benzolactam, BL) with improved selectivity for the alpha, beta and gamma isoforms to enhance sAPP secretion in fibroblasts from AD patients and in PC12 cells. Incubation (2 h) of AD fibroblasts with BL (1 and 10 microM) resulted in significant increases of sAPP secretion over basal levels. sAPP secretion in BL-treated AD cells was also slightly higher compared to control BL-treated fibroblasts, which only showed significant increases of sAPP secretion after treatment with 10 microM BL. Staurosporine (a PKC inhibitor) eliminated the effects of BL in both control and AD fibroblasts. BL and a related compound (LQ12) also caused an approximately 3-fold sAPP secretion in PC12 cells. The use of a novel and possibly non-tumorigenic PKC activator may prove useful to favor non-amyloidogenic APP processing and is, therefore, of potential therapeutic value.

Synthesis of novel chelating agents and their effect on cadmium decorporation

A series of novel dithiocarbamates, disodium salts of N-glucamyl-N-dithiocarboxyl-amino acids, were synthesized, and their usefullness as an antagonist of cadmium intoxication was investigated. These chelating agents were found to be effective in both acute and repeated exposure cadmium poisoning. The results showed that the cadmium mobilizing properties of disodium N-(2,3,4,5, 6-pentahydroxylhexyl)-N-dithiocarbamate-L-threoninate and disodium N-(2,3,4,5,6-pentahydroxylhexyl)-N-dithiocarbamate-L-cysteinate are clearly superior to those of sodium N-(4-methoxybenzyl)-D-glucamine-N-carbodithioate (MeOBGDTC) revealed in the experiments described here. The toxicity of these novel compounds is modest, and their effect on the concentrations of essential metal ions in the renal cortex is quite small in comparison with that of a group treated with cadmium only. The new dithiocarbomates were identified by MS, rather than by elemental analysis, as they were extremely hygroscopic.

Induction of microtubule-associated protein 1B expression in Schwann cells during nerve regeneration

Microtubule-associated protein 1B (MAP1B) is expressed at high levels during development of the nervous system and is localized primarily in neurons while specific phosphorylated isoforms of MAP1B are localized exclusively in growing axons. The levels of MAP1B are down regulated in most regions of the adult CNS, but remain high in neurons and axons of the PNS. This study demonstrates that the expression of MAP1B is induced in adult Schwann cells following sciatic nerve lesion and regeneration. High levels of both mRNA and the MAP1B protein were detected in Schwann cells associated with the axotomized distal stump. Expression of MAP1B was also observed in cultured primary Schwann cells from neonatal rats. The properties of the MAP1B protein in cultured Schwann cells were further characterized by Western blot analysis using specific antibodies that recognize the N-terminal, middle and C-terminal domains of MAP1B. All of these antibodies detected a protein of 320-340 kDa demonstrating that MAP1B expressed by Schwann cells is very similar, or identical, to MAP1B expressed by neurons. The phosphorylation of MAP1B in Schwann cells was also studied using monoclonal antibodies (mAb) that recognize specific phosphorylation epitopes. The results indicated that the expression of MAP1B in Schwann cells exhibited a differential phosphorylation state that was recognized by mAb 1B6 but not by other mAbs, including 1B-P, 150 and RT97, that recognize phosphorylated MAP1B in growing axons. We therefore conclude that MAP1B is expressed in Schwann cells during both development and axonal regeneration, suggesting that the developmental pattern of MAP1B in these cells is recapitulated in adult Schwann cells during the early stages of regeneration and remyelination of injured peripheral axons. The presence of MAP1B in Schwann cells may support morphological changes of these cells, particularly the formation of processes prior to their differentiation into myelin forming Schwann cells.

Functions of the perikaryon and dendrites in magnocellular vasopressin-secreting neurons: new insights from ultrastructural studies

Magnocellular hypothalamic neurosecretory neurons secreting vasopressin or oxytocin provide a robust model system for the investigation and understanding of many aspects of peptidergic neuronal function. Many of their functions and the cellular organelles involved are well understood. However, recent ultrastructural studies have thrown new light on various aspects of magnocellular neurosecretory function which have not previously received much attention. This review concerns two of these: the effects of mutations in the vasopressin gene on the handling of the translated peptide by the rough endoplasmic reticulum; and the role of the magnocellular dendrites in the production, secretion and localisation of peptides. Investigation of the synthesis of proteins derived from vasopressin genes which have undergone various mutations has at the moment provided more answers than questions: Why do some abnormal products accumulate as masses of peptide in the rough endoplasmic reticulum while others do not? Why do accumulations in humans appear to be damaging to the neurons while those in the rat do not? Investigations of the role of dendrites in the production and release of peptides show that the dendrites have all the machinery needed for protein translation and appear to synthesize locally proteins required for dendritic function. Of particular interest is the possibility that various transmitter receptor proteins could be synthesized in the dendrites close to the synapses in which they become localized. Precisely how such membrane proteins are inserted into the synaptic complex is, however, unclear, because the most part of the dendrites lack any form of the Golgi packaging organelle that can be recognised as such either by immunocytochemistry or electron microscopy. Better established is the ability of magnocellular dendrites to secrete either vasopressin or oxytocin in response to a variety of stimuli including sex steroids. This local release of peptide into the magnocellular nuclei has important but as yet incompletely defined effects on the functioning of the neurons.

[Limited diffraction beams and its application]

Limited diffraction beams have a large depth of field and thus have many applications such as medical imaging, tissue characterization, material flaw detection and blood flow detection by Doppler method. Nondiffraction beams colud be produced only by transducer with an infinity large aperture in theory. The experimental results show that limited diffraction beams produced by a limited aperture have desirable large depth of field also. The theory of this kind of beams and their applications in field of medical imaging and blood flow estimation are introduced.

Propofol, bradycardia and the Bezold-Jarisch reflex in rabbits

Propofol may cause profound bradycardia and asystole, which are mediated indirectly via cardiac innervation but could involve direct effects on the sino-atrial (SA) node and the conducting system of the heart. To test the hypothesis that propofol may also activate Bezold-Jarisch reflexes to cause bradycardia, 5-hydroxytryptamine (5-HT), veratridine and propofol were injected into the left ventricle of the heart in both intact and vagotomized rabbits. 5-HT and veratridine produced an acute, rapid, dose-dependent decrease in mean heart rate (delta HR) and a decrease in mean arterial pressure (delta MAP) together with transient but severe depression and abolition of renal sympathetic nerve activity (RSNA). Bilateral vagotomy greatly attenuated these responses; for example, at the highest dose of 5-HT (8 micrograms kg-1), delta HR, delta MAP and duration of abolition of RSNA were reduced by 57% (P < 0.001), 53% (P < 0.05) and 79% (P < 0.05), respectively. In contrast, reductions in delta HR and delta MAP produced by propofol were statistically significant only at very high doses (8 mg kg-1). Propofol depressed but did not abolish RSNA, and bilateral vagotomy had no effect on any of these responses. These results indicate that the cause of acute bradycardia after administration of propofol does not involve the Bezold-Jarisch reflex.

[Evaluation of normal submandibular gland function by sialo-scintigraphy]

OBJECTIVE

To study the normal glandular function of the submandibular gland as a background for evaluation of changes in submandibular gland diseases.

METHODS

The backgrounds of both submandibular area and temporal area were analyzed comparatively with Emission Computerized Tomography in eleven pairs of normal submandibular gland.

RESULTS

About 2.18 times of the temporal background equals to submandibular area background; the Concentrate Index of normal submandibular gland was 1.42 +/- 0.89; the Secretory Index was (109.4 +/- 39.8)%, the Secretory Index Ratio and the Concentrate Index Ratio were (77.2 +/- 17.2)% and 71.0 +/- 15.2% respectively; and the Function Index was (89.9 +/- 7.4)%.

CONCLUSION

The use of submandibular area background and functional index to represent submandibular gland function is more accurate and more sensitive. Normal functional index can provide the basis for researching submandibular gland disease.

Extensive phosphorylation and axonal transport of triton-soluble neurofilament subunits

The low abundance of soluble neurofilament (NF) subunits in mature axons has suggested that newly synthesized NF proteins rapidly assemble into highly stable polymers and associate with the Triton X-100-insoluble cytoskeleton. Here we present evidence for multiple populations of NFs and NF subunits, distinguished by differential solubility in Triton, within perikarya and axons of neurons in situ and in culture. We further demonstrate, using microinjection of "tagged" NF subunits and by pulse-chase radiolabeling of endogenous NF subunits, that these soluble NF populations represent precursors for incorporation into the axonal cytoskeleton.

TFAR19, a novel apoptosis-related gene cloned from human leukemia cell line TF-1, could enhance apoptosis of some tumor cells induced by growth factor withdrawal

Using the cDNA-representative differences analysis (cDNA-RDA) approach, we identified a novel gene, TFAR19 (TF-1 cell apoptosis related gene-19), from TF-1 cells undergoing apoptosis. The human TFAR19 encodes a protein which shares significant homology to the corresponding proteins of species ranging from yeast to mice. TFAR19 exhibits a ubiquitous expression pattern and its expression is upregulated in the tumor cells undergoing apoptosis. Overexpression of TFAR19 in tumor cells enhances apoptosis triggered by growth factor or serum deprivation. We propose that TFAR19 may play a general role in the apoptotic process.

Predicting mosquito repellent potency of N,N-diethyl-m-toluamide (DEET) analogs from molecular electronic properties

Specific molecular electronic properties of 30 N,N-diethyl-m-toluamide (DEET) analogs demonstrate functional dependence with their reported duration of protection against mosquito bites, thus providing predictors of insect repellent efficacy. No single electronic property is sufficient to predict repellent efficacy as measured by protection time, rather a set of specific electronic properties is required. Thus, the values of the van der Waals surface electrostatic potential by the amide nitrogen and oxygen atoms, the atomic charge at the amide nitrogen atom, and the dipole moment must all be in optimal ranges for potent repellency. The electronic properties were calculated using the AM semi-empirical quantum chemical method using commercial software. These easily calculable predictors of repellent efficacy should be useful in predicting the relative efficacy of newly designed compounds, thus guiding the selection of new repellents for testing.

Paclitaxel-induced apoptosis in human ovarian cancer cell line COC1

To elucidate the pattern of paclitaxel-induced apoptosis in human ovarian cancer cell line COC1 and the role of paclitaxel in chemotherapy of ovarian cancer, apoptosis was investigated in vitro by applying cytohistochemical techniques, DNA gel electrophoresis and flow cytometry. COC1 cells manifested typical apoptotic morphologic features after exposure to paclitaxel. The rate of apoptosis was enhanced within the test concentration range in a concentration-dependent pattern. At low paclitaxel concentration, the rate of apoptosis were low and the levels of mitotic arrest were high. Whereas at higher paclitaxel concentration, the rate of apoptosis were higher and the levels of mitotic arrest were relatively lower. It is concluded that the antitumor effect of paclitaxel was correlated with drug-induced apoptosis. Apoptosis induced by paclitaxel was concentration-dependent and was not significantly correlated with the mitotic arrest.

Phosphodiesterase 4B gene transcription is activated by lipopolysaccharide and inhibited by interleukin-10 in human monocytes

There are four different genes encoding the cAMP-specific phosphodiesterase (PDE4) isozymes (A, B, C, and D). cAMP has been the only agent known to induce PDE4 gene expression. In the present study, we demonstrate, for the first time, that lipopolysaccharide (LPS) significantly and selectively stimulated PDE4B mRNA production in human monocytes. The LPS stimulation occurred very rapidly (in 30-45 min) and in a dose-dependent manner (0.01-100 ng/ml). We also demonstrate that LPS induction of PDE4B mRNA expression was inhibited strongly by interleukin (IL)-10. The inhibition with IL-10 was dose-dependent (0.1-10 ng/ml). IL-4 also inhibited the LPS induction, but to a lesser extent than IL-10. PDE4B mRNA expression was also stimulated by dibutyryl-cAMP. Interestingly, unlike LPS induction, the dibutyryl-cAMP induction of PDE4B mRNA expression was not inhibited by IL-10. By performing nuclear run-on and mRNA stability assays, we demonstrate further that IL-10 inhibited LPS-stimulated PDE4B mRNA synthesis by abolishing the gene transcription rather than by enhancing mRNA degradation. The present study suggests that PDE4B, as the only LPS-inducible PDE4 subtype, may be an appropriate target for discovering anti-inflammatory drugs.

[Carcinoma of the lips developing in discoid lupus erythematosus]

OBJECTIVE

This clinical study was designed to learn the diagnosis and treatment of lip carcinoma developing in discoid lupus erythematosus.

METHODS

One hundred and eighty-one of squamous cell carcinoma of the lips treated in our department from 1980 to 1995 were retrospectively studied.

RESULTS

Ten cases of the 181 lip carcinoma (5.5%) had concomitant discoid lupus erythematosus (DLE) of the vermilion border of the lower lip.

CONCLUSION

Bleomycin or radiotherapy is the best treatment for the disease.

[A preliminary study on the relationship between nutritional status and postoperative complications in patients with head and neck malignancies]

OBJECTIVES

To study the role of nutritional factor in the development of postoperative complications in patients with head and neck malignancies.

METHODS

Postoperative complications of 96 patients with head and neck malignancies who were operated on were surveyed. Twenty-seven developed postoperative complications; the remaining 69 went uneventful. Comparisons of nutritional status and clinical variables between these two groups were made.

RESULTS

1. The prevalence of poor preoperative nutritional status in the complication group (56%) was higher as compared with that in the noncomplication group (20%) (P < 0.001); 2. values of body weight, triceps skin fold thickness, arm circumference, arm muscle circumference, and creatinine-height index in the complication group decreased much more significantly than in the noncomplication group (P < 0.001); 3. the nitrogen and calorie intake within the first postoperative week was lower in the complication group than in the non-complication group (P < 0.001).

CONCLUSIONS

Nutritional factor plays a very important role in the development of postoperative complication and the perioperative nutritional support for head and neck surgical patients should not be ignored.

Surgery for intestinal graft-versus-host disease: report of two cases

PURPOSE

With allogeneic bone marrow transplantation becoming increasingly common, intestinal graft-versus-host disease often is seen within specialized transplant units. Surgeons are involved infrequently in the management of such patients, and yet occasionally are called upon to operate on critically ill patients with refractory disease. This article reviews the salient features of this condition and discusses possible indications for surgery.

METHOD

Two cases of intestinal graft-versus-host disease that required laparotomy are presented.

RESULTS

A 24-year-old male with severe, unremitting, acute intestinal graft-versus-host disease underwent small-bowel and large-bowel resections for massive bleeding. A 35-year-old male with recurrent symptoms of small-bowel obstruction after allogeneic bone marrow transplantation underwent small-bowel resection and multiple strictureplasties for chronic intestinal graft-versus-host disease.

CONCLUSION

Surgery can be performed for complications of intestinal graft-versus-host disease not responding to medical therapy, with successful outcome.

[Isolation and identification of Agrobacterium spp. from cherry crown galls and their sensitivities to agrocin 84]

Crown galls were sampled from cherry yards of Shandong, Hebei, and Liaoning provinces. 46 pathogenic strains were isolated. Physiological and biochemical tests revealed that 4 strains were Agrobacterium tumefaciens(bio. 1) and that the other 42 strains were A. rhizogenes (bio. 2), according to the classifications and nomenclatures of the genus Agrobacterium and the species revised by Sawada et al and Bouzar. The Ti plasmids of all strains were nopaline type. All strains were sensitive to agrocin 84, which suggested that crown gall disease of cherry could be controlled by K84 strain.

Metabolism of cystathionine, N-monoacetylcystathionine, perhydro-1,4-thiazepine-3,5-dicarboxylic acid, and cystathionine ketimine in the liver and kidney of D,L-propargylglycine-treated rats

Experimental cystathioninuria was induced by injection of D,L-propargylglycine in rats. The novel cystathionine metabolites, N-monoacetylcystathionine (NAc-cysta), perhydro-1,4-thiazepine-3,5-dicarboxylic acid (PHTZDC), and cystathionine ketimine (CK), were identified previously in the urine of patients with cystathioninuria and D,L-propargylglycine-treated rats. In this study, we identified these compounds in the liver and kidney of D,L-propargylglycine-treated rats using liquid chromatography-mass spectrometry with an atmospheric pressure chemical ionization interface system (LC/APCI-MS) and an amino acid analyzer. The metabolism of these compounds in the liver and kidney of D,L-propargylglycine-treated rats was also studied. PHTZDC, NAc-cysta, and CK were accumulated in the rat tissues in proportion to the content of cystathionine after D,L-propargylglycine administration. The concentrations of these compounds in the liver were higher than those in the kidney, and these compounds reached maxima earlier in the liver than in the kidney.

Synthesis and biological evaluation of two analogues of (S)-alpha-methyl-3-carboxyphenylalanine

Two analogues 2, 3 of (S)-alpha-methyl-3-carboxylphenylalanine 1 were synthesized to test their activity for metabotropic glutamate receptors (mGluRs). Both compounds 2 and 3 were inactive as antagonist for mGluRs, but 2 showed weak agonistic activity for GluR6 in contrast to that reported by Kemp and co-workers.

Rituximab (anti-CD20 monoclonal antibody) for the treatment of patients with relapsing or refractory aggressive lymphoma: a multicenter phase II study

Rituximab, a chimeric monoclonal antibody that binds specifically to the CD20 antigen, induced objective responses in 50% of patients with low-grade or follicular B-cell lymphoma. Because most nonfollicular B-cell lymphomas also express the CD20 antigen, we conducted a phase II study to evaluate the efficacy and tolerability of this new agent in patients with more aggressive types of lymphoma. Patients with diffuse large B-cell lymphoma (DLCL), mantle cell lymphoma (MCL), or other intermediate- or high-grade B-cell lymphomas according to the Working Formulation were included in this prospective randomized phase II study if they were in first or second relapse, if they were refractory to initial therapy, if they progressed after a partial response to initial therapy, or if they were elderly (age >60 years) and not previously treated. The patients received 8 weekly infusions of rituximab at the dose of 375 mg/m2 in arm A or one infusion of 375 mg/m2 followed by 7 weekly infusions of 500 mg/m2 in arm B. Patients were evaluated 2 months after the last rituximab infusion. Fifty-four patients were randomized from 9 centers in Europe and Australia (28 in arm A and 26 in arm B). A total of 5 complete responses (CR) and 12 partial responses (PR) were observed among the 54 enrolled patients, with no difference between the two doses. In an intent-to-treat analysis, the CR rate was 9% (CI95%, 3% to 20%) and the PR rate was 22% (CI95%, 12% to 36%), for an overall response rate of 31% (CI95%, 20% to 46%). An analysis of prognostic factors showed that response rates were lower in patients with refractory disease, patients with lymphoma not classified as DLCL, and patients with a tumor larger than 5 cm in diameter. DLCL and MCL patients had response rates of 37% and 33%, respectively. The median time to progression exceeded 246 days for the 17 responding patients. The most frequently reported adverse events were related to an infusion syndrome and were mild: 19% of the patients had a grade 3 related adverse event, slightly more in arm B, and only 1 patient had a grade 4 related adverse event in arm A. Two patients (3.7%) withdrew from treatment because of severe adverse events, one patient in each arm. In this first trial of rituximab in DLCL and MCL, patients experienced a significant clinical activity with a low toxicity. Rituximab has significant activity in DLCL and MCL patients and should be tested in combination with chemotherapy in such patients.

[Recovery of submandibular gland function following transoral sialolithectomy]

OBJECTIVE

Investigate the recovery of the submandibular gland function following transoral sialolithectomy.

METHODS

The glandular function of 26 patients who received the transoral sialolithectomy were investigated by sequential scintigraphy with 99m Tc pertechetate.

RESULTS

Most glandular function recovers normal in short time after operation. Glandular infection, calculus diameter and patients's age could influence the recovery of function.

CONCLUSION

In the treatment of sialolithiasis, breaking up the pathogenic process of calculus formation and effectively controlling the glandular infection are very important in preventing from the function reduction. After transoral sialolithectomy preserving the anatomical normal orifice of the duct, and using silivators may be very favorable for the function recovery.

Conditions affecting enhanced corneal allograft survival by oral immunization

PURPOSE

To determine the optimal conditions for enhancing corneal allograft survival by oral immunization with donor-specific alloantigens.

METHODS

CB6F1 mice were orally immunized with various doses of C3H/Hej corneal epithelial and endothelial cells before receiving orthotopic C3H/Hej corneal allografts. Paraformaldehyde-fixed corneal cells were compared with viable corneal cells for their capacity to promote corneal allograft survival. The mucosal adjuvant, cholera toxin B (CTB), was examined for its capacity to enhance corneal graft survival when given separately or conjugated to corneal cells used for oral immunization. Oral immunization was also evaluated for its capacity to prevent immunologic rejection in three high-risk settings: preimmunized hosts, hosts with prevascularized graft beds, and grafts that contain donor-specific Langerhans' cells.

RESULTS

Optimal graft survival occurred when 2 x 10(6) corneal cells were administered orally 10 days before orthotopic corneal transplantation. Paraformaldehyde-fixed corneal cells were as effective as viable cells in preventing corneal graft rejection. Cholera toxin B enhanced the efficacy of oral immunization when conjugated with the orally administered corneal cells but was ineffectual when administered separately. Oral immunization with donor corneal cells enhanced corneal graft survival in all three high-risk settings.

CONCLUSIONS

Oral immunization with donor cells is an effective strategy for enhancing corneal graft survival and preventing graft rejection in high-risk settings. Graft enhancement is optimized when the orally administered cells are conjugated with CTB and administered before corneal transplantation. Because fixed cells retain their capacity to enhance corneal graft survival, it may be possible to store donor cells for long-term use in high-risk hosts.

Predictors and outcome of admission for invasive Streptococcus pneumoniae infections at a Canadian children's hospital

Rates of admission for invasive Streptococcus pneumoniae infection in children vary considerably between institutions. We performed a retrospective study to investigate factors used in the decision to admit patients with invasive S. pneumoniae infection to Alberta Children's Hospital. Of 254 patients who were initially assessed in the emergency department, 38.2% were admitted to the hospital. Significant risk factors for admission as determined by a logistic regression model included murmur (odds ratio [OR], 18.98; 95% confidence interval [CI], 4.08-88.23), focal infection (OR, 11.41; 95% CI, 5.07-25.67), and older age (OR, 2.72; 95% CI, 1.03-7.17). Higher hemoglobin level (OR, 0.96; 95% CI, 0.93-0.99) and temperature of > 38.5 degrees C (OR, 0.39; 95% CI, 0.18-0.85) were associated with a lower risk of admission. Two patients died (case-fatality rate, 0.7%). Despite the low rate of admission for invasive S. pneumoniae infections at our hospital, the mortality rate was comparable with those at institutions with higher rates of admission, thus suggesting that the factors we identified may be useful in deciding whether to admit patients with (or who are at high risk for) invasive S. pneumoniae infections.

Restoration of TEA-induced calcium responses in fibroblasts from Alzheimer's disease patients by a PKC activator

Several alterations in fibroblasts of Alzheimer's disease (AD) patients have been described, including alterations in calcium regulation, protein kinase C (PKC), and potassium (K+) channels. Studies have also found reduced levels of the alpha isoform of PKC in brains and fibroblasts of AD patients. Since PKC is known to regulate ion channels, we studied K+ channel activity in fibroblasts from AD patients in the presence of (2S, 5S)-8-(1-decynyl)benzolactam (BL), a novel activator of PKC with improved selectivity for the alpha, beta, and gamma isoforms. We present evidence for restoration of normal K+ channel function, as measured by TEA-induced [Ca2+]i elevations, due to activation of PKC by BL. Representative patch-clamp data further substantiate the effect of BL on restoration of 113pS K+ channel activity. Immunoblotting analyses using an alpha-isozyme-specific PKC antibody confirm that BL-treated fibroblasts of AD patients show increased PKC activation. The present study suggests that PKC activator-based restoration of K+ channels may offer another approach to the investigation of AD pathophysiology, which in turn could lead to the development of a useful model for AD therapeutics.

[Animal experiment and clinical application of self-made mechanically detachable coils]

OBJECTIVE

To evaluate the practical and thrombogenetic characteristics of self-made mechanically detachable coils by the animal experiment and primary clinical application.

METHOD

The bifurcation type of aneurysm model was established on rabbit and embolized with self-made mechanically detachable coils 2 weeks after surgery. 24 coils were used in 5 experimental aneurysms. Control angiography was performed and the rabbits were sacrificed 2 - 3 weeks after the embolization. The embolized aneurysm samples were examined by pathologist. Ten patients were treated with self-made mechanically detachable coils in primary clinical application. They were divided into aneurysms (7 patients), traumatic carotid-carvenous fistulas (2), dural arterio-venous fistula in carvenous sinus region (1). 146 coils were used totally and all were delivered with mechanical detachable system (MDS Balt co. France).

RESULT

Pathologically, the cavities of rabbit aneurysm models were occluded by tungsten coils (2 complete, 3 almost complete). The coils were trapped in granulation tissue which was covered by a thin layer of endothelium on the surface facing the blood flow. In the coils dense packing ones, the aneurysms were completely excluded from the parent circulation by neointimal layers. In the practice procedures, the coils fit MDS (Balt co. France) very well and can be delivered, withdrew and detached smoothly.

CONCLUSION

The self-made mechanically detachable coils have practical reliability and evident thrombogenetic effects.

Synergism between sevoflurane and intravenous fentanyl on A delta and C somatosympathetic reflexes in dogs

In this study, we defined the nature of the interactions between sevoflurane and fentanyl on spontaneous and reflex-evoked sympathetic activity, resting heart rate (HR), and mean arterial pressure (MAP). Spontaneous renal sympathetic nerve activity (RSNA) and A delta- and C-fiber-mediated somatosympathetic reflexes, evoked by electrical stimulation of radial nerves, and HR and MAP were recorded in anesthetized dogs. In one group, the effects of incremental doses of 2-64 micrograms/kg fentanyl i.v. were observed. It had a greater inhibitory effect on C than on A delta reflexes, which were abolished by mean cumulative doses of 64 micrograms/kg and approximately 128 micrograms/kg, respectively. Although 1.5% sevoflurane reduced C reflexes by 28% and A delta reflexes by only 12%, it reduced the total doses of fentanyl required for their abolition to 32 micrograms/kg and 64 micrograms/kg, respectively. Mean RSNA, HR, and MAP values were reduced by 46%, 54%, and 30%, respectively, by fentanyl alone and by 23%, 11%, and 17%, respectively, in response to 1.5% sevoflurane. The combination of fentanyl and sevoflurane caused reductions of 44%, 54%, and 41%, respectively, which indicates a less than additive effect. These results indicate that sevoflurane interacts synergistically with fentanyl to depress A delta and C somatosympathetic reflexes, whereas for RSNA, HR, and MAP, their effects were less than the additive.

IMPLICATIONS

Although fentanyl caused a greater depression of C than of A delta reflexes to the point of abolition, the maximal depression of spontaneous sympathetic activity, heart rate, and arterial pressure occurred at smaller doses. The combined depressant effects of sevoflurane and fentanyl were synergistic on somatosympathetic reflexes but were less than additive on spontaneous sympathetic activity, heart rate, and arterial pressure.

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

BACKGROUND

It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e.g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic.

METHODS

PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 microgram.kg-1 i.v. or midazolam 0.05 mg.kg-1 i.v. on the effects of propofol and fentanyl respectively on PNA were studied.

RESULTS

Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg.kg-1 i.v. and 32 micrograms.kg-1 i.v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg.kg-1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg.kg-1. The mean ED50s, calculated from dose-response curves, were 5.4 mg.kg-1, 3.9 micrograms.kg-1 and 0.4 mg.kg-1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 microgram.kg-1 i.v. or midazolam 0.05 mg.kg-1 i.v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg.kg-1 and 8 micrograms.kg-1, respectively.

CONCLUSION

Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.

Lidocaine prolongs the safe duration of circulatory arrest during deep hypothermia in dogs

PURPOSE

To test the hypothesis that lidocaine prolongs the safe period of circulatory arrest during deep hypothermia.

METHODS

Sixteen dogs were subjected to cooling, first surface cooling to 30 degrees C and then core cooling to 20 degrees C rectal temperature). The circulation was then stopped for 90 min. In the lidocaine group, 4 mg.kg-1 lidocaine was injected into the oxygenator two minutes before circulatory arrest and 2 mg.kg-1 at the beginning of reperfusion and rewarming. The control group received equivalent volumes of normal saline. Post-operatively, using a neurological deficit scoring system (maximum deficit score-100; minimum-zero indicating that no scored deficit could be detected). Neurological function was evaluated hourly for six hours and then daily for one week, the pharmacokinetic parameters were calculated using one compartment model.

RESULTS

On the seventh day, the neurological deficit score and overall performance were better in the lidocaine (0.83 +/- 2.04) than in the control group (8.33 +/- 4.08 P < 0.05). During the experiment, the base excess values were also better in the lidocaine than in the control group (at 30 min reperfusion: -4.24 +/- 1.30 vs -8.20 +/- 2.82 P < 0.01, at 60 min reperfusion was -3.34 +/- 1.87 vs -7.52 +/- 2.40 (P < 0.01). On the eighth day the extent of pathological changes were milder in the lidocaine group than that in the control group. The elimination half life of lidocaine was 40.44 +/- 7.99 during hypothermia and 2.01 +/- 4.56 during rewarming.

CONCLUSIONS

In dogs lidocaine prolongs the safe duration of circulatory arrest during hypothermia.