[Clinical efficacy of induction chemoimmunotherapy for locally advanced hypopharyngeal carcinoma: a prospective phase Ⅱ study]

Objective: To evaluate the objective response rate (ORR) of induction chemoimmunotherapy with camrelizumab plus TPF (docetaxel, cisplatin, and capecitabine) for locally advanced hypopharyngeal squamous cell carcinoma (LA HSCC) and potential predictive factors for ORR. Methods: A single-center, prospective, phase 2 and single-arm trial was conducted for evaluating antitumor activity of camrelizumab+TPF(docetaxel+cisplatin+capecitabine) for LA HSCC between May 21, 2021 and April 15, 2023, patients admitted to the Eye & ENT Hospital affiliated with Fudan University. The primary endpoint was ORR, and enrolled patients with LA HSCC at T3-4N0-3M0 received induction chemoimmunotherapy for three cycles: camrelizumab 200 mg day 1, docetaxel 75 mg/m2 day 1, cisplatin 25 mg/m2 days 1-3, and capecitabine 800 mg/m2 days 1-14. Patients were assigned to radioimmunotherapy when they had complete response or partial response (PR)>70% (Group A), or assigned to surgery plus adjuvant radiotherapy/chemoradiotherapy when they had PR≤70% (Group B), and the responses were defined by using tumor volume evaluation system. Tumor diameter was also used to assess the treatment responses by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Use SPSS 23.0 software was used to analyze the data. Results: A total of 51 patients were enrolled who underwent the induced chemoimmunotherapy for three cycles, and all were males, aged 35-69 years old. After three cycles of induction immunochemotherapy, 42 (82.4%) patients existed in Group A (complete response or PR>70%) and 9 patients (17.6%) in Group B (PR≤70%), the ORR was 82.4%. The primary endpoint achieved expected main research objectives. Compared to the patients of Group A, the patients of Group B showed the higher T stage and the larger volume of primary tumor before induced immunochemotherapy, and also had the less regression of tumor volume after induced immunochemotherapy (all P<0.05). The optimal cutoff value of pre-treatment tumor volume for predicting ORR was 39 cm3. The T stage (OR=12.71, 95%CI: 1.4-112.5, P=0.022) and the volume (OR=7.1, 95%CI: 1.4-36.8, P=0.018) of primary tumor were the two main factors affecting ORR rate of induction chemoimmunotherapy. Conclusion: The induction chemoimmunotherapy with camrelizumab plus TPF shows an encouraging antitumor efficacy in LA HSCC.

[Indications and complications prevention and management of phaseⅡ implantation of Provox Vega voice prosthesis after total laryngectomy]

Objective: To explore the indications and management of common postoperative complications of phase II tracheoesophageal puncture (TEP) for Provox Vega voice prosthesis after total laryngectomy. Methods: The clinical data of 20 patients undergoing phase II TEP for Provox Vega voice prosthesis in our hospital between May 2021 and January 2022 were analyzed. Among them, there were 19 males and 1 female, aged from 37 to 76 years, with an average age of (60.0±8.4)years. The surgical indications and the prevention and treatment of common postoperative complications were summarized. Descriptive analysis was used in this research. Results: The basic surgical indications were as following: after total laryngectomy, there was no stenosis of the stoma and esophagus entrance, no scar constitution, no mouth opening restriction, no stiffness and backward restraint of the neck after radiotherapy, and more than half a year apart surgery or radiotherapy. Among the 20 patients, 18 underwent implantation successfuly, 1 failed in the operation, and for 1 patient, the prosthesis was removed due to bleeding 1 week after implantation. The common postoperative complications included TEP fistula infection (2 cases), the TEP fistula bleeding(1 case), deep neck (prevertebral) abscess (1 case), granulation at the inner side of the TEP fistula (1 case), invagination of the prosthesis (2 cases) and leakage around the prosthesis (2 cases). All patients were cured with different interventions. Conclusions: The Provox Vega voice prosthesis is generally safe for phase Ⅱ implantatione, but implantation indications need to be established. Common postoperative complications can be solved through preventive and remedial interventions.

[Feasibility and perioperative safety of transoral robotic surgery with da Vinci Xi platform]

Objective: To explore the feasibility and perioperative safety of transoral robotic surgery with da Vinci Xi platform for pharyngolaryngeal tumors. Methods: A retrospective analysis was performed on 55 consecutive cases with resection of pharyngolaryngeal tumors by transoral robotic surgery with da Vinci Xi platform from July 27, 2020 to October 31, 2021 in the Department of Head and Neck Surgery, Fudan University Eye, Ear, Nose and Throat Hospital, including 44 males and 11 females, aged 25-79 years. There were 41 cases of oropharyngeal tumors, 9 cases of parapharyngeal space tumors, 2 cases of laryngeal tumors, 2 cases of hypopharyngeal tumors and 1 case of retropharyngeal space tumor. Operative time, intraoperative blood loss, postoperative hospital stay, perioperative tracheotomy, nasal feeding, hemorrhage and other complications were analyzed. Results: Of the 55 patients, 54 received resection of pharyngolaryngeal tumors by da Vinci robot through oral approach, and only 1 case of pyriform sinus carcinoma underwent a conversion to open surgery due to poor exposure of lower margin. The average surgical time for the patients with transoral robotic surgeries was 64.4 min, the average blood loss was 24.8 ml, the average postoperative hospital stay was 6.9 d, and the average oral feeding time was 11.1 d. Seventeen patients (30.9%) underwent preventive tracheotomy during surgery. Among 38 cases of laryngeal cancer, 28 underwent simultaneously neck dissection. No serious complications occurred in all patients during and after operation. The follow-up time was 1-15 months. Aside from 1 patient had a relapse 10 months after surgery, other patients had no recurrence or metastasis. Conclusion: Transoral robotic surgery with da Vinci Xi is safe, effective and minimally invasive for resection of pharyngolaryngeal tumors under reasonable indications.

SPHK2 protein expression, Ki-67 index and infiltration of tumor-associated macrophages (TAMs) in human glioma

INTRODUCTION

Sphingosine kinases (SPHKs), the Ki-67 index and tumor-associated macrophages (TAMs) are associated with diverse human malignancies, including glioma. SPHK2, a subtype of SPHKs, has not been assessed in glioma or correlated with the Ki-67 index or TAM infiltration. We tested the hypothesis that expression of SPHK2 correlates with the Ki-67 index and TAM infiltration in patients with glioma.

MATERIALS AND METHOD

Western blot analysis was performed on protein lysates prepared from human astrocyte (HA) and glioma cell lines. Immunofluorescence was used to determine the subcellular location of SPHK2 protein in glioma cells. Next, immunohistochemistry was employed to analyze the correlations among SPHK2, Ki-67, CD68, and CD206 in 11 non-neoplastic brain tissues and 60 glioma tissues. All slides were evaluated under ×400 magnification, and the ratio of positively stained cells to the total number of cells was calculated for analysis.

RESULTS

SPHK2, CD68 and CD206 were all increased in glioma tissues compared to non-neoplastic brain tissues, but there were no differences between WHO grades of glioma. Ki-67 was highest in WHO grade IV tumors and lowest in non-neoplastic brain tissues, and all between-group differences were statistically significant. Moreover, SPHK2 expression was positively correlated with the Ki-67, CD68 and CD206 indexes. Finally, the CD68 and CD206 indexes were both associated with the Ki-67 index.

CONCLUSION

SPHK2 protein expression, the Ki-67 index and TAM infiltration in human glioma tissue were reported in this study for the first time. SPHK2 was positively associated with TAM infiltration and glioma proliferation. Mechanistically, SPHK2 may promote glioma growth by stimulating TAMs to polarize M2-type macrophages.

[Effect of preoperative monocyte-lymphocyte ratio on prognosis of patients with resectable esophagogastric junction cancer]

Objective: To investigate the associations between various blood test parameters including MLR (monocyte-lymphocyte ratio) and prognosis in post-operative esophagogastric junction cancer patients. Methods: We retrospectively studied the preoperative and postoperative data of 309 patients who underwent radical surgery for esophagogastric junction cancer. The relationship between MLR, neutrophil lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and overall survival (OS) was analyzed. Results: The cutoff values of MLR、NLR and PLR were 0.201, 1.697 and 96.960, respectively. The median OS was 51.4 months for all the patients in the study group (n=309). MLR in patients with esophagogastric junction carcinoma was associated with gender, depth of invasion, histological grade, TNM stage, NLR and PLR (P<0.05). PLR was associated with tumor size, TNM stage, NLR and MLR (P<0.05). NLR was associated with gender, tumor size, TNM stage, PLR and MLR (both P<0.05). Univariate analysis showed that tumor size, depth of tumor invasion, metastasis of lymph nodes, pathological grading, nerve infiltration, lymphovascular invasion, TNM staging, PLR and MLR were associated with the median overall survival time (P<0.05). Multivariate analysis showed that TNM stage, nerve infiltration and MLR were independent prognostic predictors for patients with esophagogastric junction cancer (P<0.05), but not PLR or NLR. Setting the optimal cut-off value of the MLR in 0.201, the area under the curve was 0.603, significantly larger than that of PLR and NLR (P<0.05). Conclusions: Preoperative MLR is a very useful predictor of patients with esophagogastric junction cancer who underwent radical rescetion. Preoperative MLR> 0.201 is an independent risk factor for postoperative survival in patients with esophagogastric cancer, and PLR> 96.960 may predict a poor prognosis risk.

[Changes of the expression for genes related with senescence and the telomerase activity during cellular replicative and premature senescence in human embryonic lung fibroblasts]

Objective: To detect the alterations of telomerase activity and the expression for oxidative stress responsive genes related with senescence during cellular replicative senescence and hydrogen peroxide-induced premature senescence in human embryonic lung fibroblasts (HELFs) in vitro. Methods: The HELFs were divided into young cells (22 population doubling levels, 22PDL) , mid-aged cells (35PDL) and replicative senes-cent cells (49PDL) and premature senescent cells induced by H(2)O(2)(premature senescence, PS). The telomerase activity was detected by ELISA assay during cellular replicative and premature senescence. The mRNA level of oxidative stress responsive genes related with senescence for Foxo1, Foxo3, Pdx1, apoA-I and MMP1 was per-formed by RT-Q-PCR separately. Results: The mRNA level for Foxo1, Foxo3, apoA-I and Pdx1 was decreased separately during cellular replicative senescence compared to that in the young-stage cells with statistical signifi-cance (P<0.05). The expression of MMP1 was up-regulated 5.1-fold obviously (P<0.05). In premature senes-cence, the mRNA level was only decreased for Foxo1, Foxo3 and apoA-I, but up-regulated 2.3-fold and 6.2-fold for Pdx1 and MMP1 respcetively vs 22PDL significantly (P<0.05). The telomerase activity in young cells was not detected, and it increased in mid-aged cells and replicative senescence stages during cellular replicative se-nescence as compared to 22PDL with statistical significance (P<0.05). The telomerase activity in premature se-nescence was highly active. Conclusion: The expression for genes related with senescence has differences be-tween replicative and premature senescence and hydrogen peroxide modifies their expression levels. The telomer-ase activity has been going up with increased PDLs.

Secondhand smoke exposure of children at home and prevalence of parental smoking following implementation of the new tobacco control law in Macao

OBJECTIVE

To investigate secondhand smoke exposure (SHS) of children at home and the prevalence of parental smoking after implementation of the new tobacco control law in Macao. This study explored whether the smoking ban in public places in Macao has decreased the prevalence of smoking or led to increased SHS exposure of children at home. As smokers cannot smoke in public places any more, they may smoke at home more frequently; a displacement effect of smoke-free legislation.

STUDY DESIGN

Cross-sectional survey.

METHODS

This study surveyed 337 fathers and 538 mothers. Questions from a subset of key questions from the Global Adult Tobacco Survey (2nd edition) were applied to assess the SHS exposure of children and the prevalence of parental smoking since the smoking ban. A classification tree analysis was used to analyse the factors increasing SHS exposure of children.

RESULTS

The prevalence of SHS exposure in children at home was 41.3%. The prevalence rates of paternal and maternal smoking were 43.7% and 3.8%, respectively. Compared with data reported by the Health Bureau of Macao SAR in 2011, the prevalence of parental smoking and the prevalence of SHS exposure of children at home have not decreased since the smoking ban. Analysis of the factors increasing the prevalence of SHS exposure of children indicated that fathers with an education level below high school were more likely to contribute to this increase, compared with fathers with a high school education or more (48.2% vs 32.4%, respectively). In addition, fathers represented the majority of smokers at home, accounting for 92.0% of 415 smoking parents. The prevalence of paternal smoking (82.0%) in the group of children with SHS exposure was much higher than that in the unexposed group (16.7%, Chi-squared test = 367.199, P = 0.000). The SHS exposure of children increased consistently with the decrease in paternal education level. This was consistent with the increasing prevalence of paternal smoking as paternal education level decreased. SHS exposure was most common among children whose fathers had an education level below high school and whose mothers were aged ≤29 years (75.0%).

CONCLUSIONS

This study did not find any decline in the prevalence of parental smoking after the smoking ban. These parents were more likely to smoke at home after the ban, leading to more frequent SHS exposure for their children.

Preparation and characterization of an ordered 1-dodecanethiol monolayer on bare Si(111) surface

We have grown 1-dodecandthiol (DDT) monolayer on a bare Si(111) surface through ultraviolet-assisted photochemical reaction. The resulting monolayer was investigated by means of water contact angle measurement, synchrotron radiation-based high-resolution X-ray photoelectron spectroscopy, and polarization-dependent near-edge X-ray absorption fine structure spectroscopy. These combined probes for characterization reveal a hydrophobic ambient surface; the DDT was directly attached to Si through a Si-S bond, and the molecules formed an ordered monolayer with an average tilt angle of 57° of the alkyl chains relative to the substrate surface.

Effects of supplemental copper and chromium on the serum and egg traits of laying hens

1. This study investigated the effects of supplemental copper and chromium on the serum and egg traits of laying hens using 144 forty-five-week-old White Leghorn layers. The hens were randomly assigned into 9 groups to conduct this 3 copper (0, 125 and 250 mg/kg as copper sulphate) x 3 chromium (0, 800 and 1600 microg/kg as chromium picolinate) factorial trial. 2. Egg yolk cholesterol was significantly reduced by supplementary copper (Cu) and chromium (Cr) and there was an interaction between Cu and Cr supplementation. Egg production, egg weight, eggshell strength and eggshell thickness were not influenced by Cu or Cr supplementation. 3. Serum cholesterol concentration was decreased by Cu supplementation and very low-density lipoprotein (VLDL) was reduced markedly by both Cu and Cr. On the other hand, high-density lipoprotein (HDL) was significantly increased by Cu and Cr. Interaction occurred between Cu and Cr in the VLDL and HDL parameters. Supplmentary Cu also reduced VLDL-cholesterol (VLDL-C) and enhanced HDL-cholesterol (HDL-C), while supplemental Cr had a contrary effect on these two parameters. 4. If minimum egg cholesterol content is the criterion, this study suggests that 125 mg/kg of Cu together with 800 to 1600 microg/kg of Cr provide adequate supplementary concentrations for laying hens.

Expressed transcripts associated with high rates of egg production in chicken ovarian follicles

The purpose of this study was to characterize differentially expressed transcripts associated with varying rates of egg production in Taiwan country chickens. Ovarian follicles were isolated from two strains of chicken which showed low (B) or high (L2) rates of egg production, then processed for RNA extraction and cDNA library construction. Three thousand and eight forty clones were randomly selected from the cDNA library and amplified by PCR, then used in microarray analysis. Differentially expressed transcripts (P<0.05, log(2)> or = 1.75) were sequenced, and aligned using GenBank. This analysis revealed 20 non-redundant sequences which corresponded to known transcripts. Eight transcripts were expressed at a higher level in ovarian tissue prepared from chicken strain B, and 12 transcripts were expressed at a higher level in L2 birds. These differential patterns of expression were confirmed by semi-quantitative RT-PCR. We show that transcripts of cyclin B2 (cycB2), ferritin heavy polypeptide 1 (FTH1), Gag-Pol polyprotein, thymosin beta4 (TB4) and elongation factor 1 alpha1 (EEF1A1) were enriched in B strain ovarian follicles. In contrast, thioredoxin (TXN), acetyl-CoA dehydrogenase long chain (ACADL), inhibitor of growth family member 4 (ING4) and annexin II (ANXA2) were expressed in at higher levels in the L2 strain. We suggest that our approach may lead to the isolation of effective molecular markers that can be used in selection programs in Taiwan country chickens.

Spontaneous rhythmic field potentials of isolated mouse hippocampal-subicular-entorhinal cortices in vitro

The rodent hippocampal circuit is capable of exhibiting in vitro spontaneous rhythmic field potentials (SRFPs) of 1-4 Hz that originate from the CA3 area and spread to the CA1 area. These SRFPs are largely correlated with GABA-A IPSPs in pyramidal neurons and repetitive discharges in inhibitory interneurons. As such, their generation is thought to result from cooperative network activities involving both pyramidal neurons and GABAergic interneurons. Considering that the hippocampus, subiculum and entorhinal cortex function as an integrated system crucial for memory and cognition, it is of interest to know whether similar SRFPs occur in hippocampal output structures (that is, the subiculum and entorhinal cortex), and if so, to understand the cellular basis of these subicular and entorhinal SRFPs as well as their temporal relation to hippocampal SRFPs. We explored these issues in the present study using thick hippocampal-subicular-entorhinal cortical slices prepared from adult mice. SRFPs were found to spread from the CA1 area to the subicular and entorhinal cortical areas. Subicular and entorhinal cortical SRFPs were correlated with mixed IPSPs/EPSPs in local pyramidal neurons, and their generation was dependent upon the activities of GABA-A and AMPA glutamate receptors. In addition, the isolated subicular circuit could elicit SRFPs independent of CA3 inputs. We hypothesize that the SRFPs represent a basal oscillatory activity of the hippocampal-subicular-entorhinal cortices and that the subiculum functions as both a relay and an amplifier, spreading the SRFPs from the hippocampus to the entorhinal cortex.

Synthesis and characterization of aspartic acid complexes of antimony and bismuth triiodide

New bioinorganic complexes of the aspartic acid with the antimony or bismuth triiodide were synthesized by a direct solid-solid reaction at room temperature. The formula of the complex is MI(3)[OOCCH(2)CH(NH(2))CO](2.5) x 2.5H(2)O (M = Sb, Bi). The complex may be a dimer with bridge structure. The crystal structure of the complexes belongs to a triclinic system. The lattice parameters are a = 0.9883 nm, b = 1.4284 nm, c = 2.0114 nm, alpha = 94.46 degrees , beta = 99.76 degrees and gamma = 100.1 degrees for the complex of antimony and a = 0.9756 nm, b = 1.4560 nm, c = 1.9875 nm, alpha = 94.18 degrees , beta = 97.25 degrees and gamma = 101.16 degrees for the complex of bismuth. The infrared spectra and thermal analyses can demonstrate the complex formation between the aspartic acid and the antimony or bismuth ion.

Postnatal development of intrinsic GABAergic rhythms in mouse hippocampus

The local circuitry of the mammalian limbic cortices, including the hippocampus, is capable of generating spontaneous rhythmic activities of 0.5-4 Hz when isolated in vitro. These rhythmic activities are mediated by synchronous inhibitory postsynaptic potentials in pyramidal neurons as the result of repeated discharges of inhibitory interneurons. As such, they are thought to represent an intrinsic inhibitory rhythm. It is unknown at present whether such a rhythm occurs in the immature rodent hippocampus and, if so, the postnatal time window in which it develops. We explored these issues using our recently developed whole mouse hippocampal isolate preparation in vitro. We found that spontaneous rhythmic field potentials started to emerge in mouse hippocampal isolates around postnatal day 10, stabilized after postnatal day 15 and persisted into adulthood. In postnatal days 11-14 mouse hippocampi, the properties of these rhythmic potentials were in keeping with a CA3-driven, IPSP-based intrinsic network activity. The lack of spontaneous field rhythm in neonatal (postnatal days 2-7) hippocampi cannot be attributed to the excitatory activities mediated by gamma-aminobutyric acid type A (GABA-A) receptors, as chloride-dependent hyperpolarizing inhibitory postsynaptic potentials were detectable in neonatal pyramidal neurons at voltages near resting potentials and pharmacological antagonisms of GABA-A receptors produced robust epileptiform discharges in neonatal hippocampi. High frequency afferent stimulation or applications of 4-aminopyridine at low micromolar concentrations failed to induce persistent field rhythm in neonatal hippocampi, suggesting that an overall weak glutamatergic drive is not the sole causing factor. We suggest that the inhibitory postsynaptic potential-based spontaneous rhythmic field potentials develop in a discrete time window during the second postnatal week in the mouse hippocampus due to a fine-tuning in the structure and function of CA3 recurrent circuitry and associated GABAergic inhibitory interneurons.

Ca3 neuronal activities of dorsal and ventral hippocampus are differentially altered in rats after prolonged post-ischemic survival

The aim of the present study is to explore the potential hyper-excitability of hippocampal CA3 neurons in rats after prolonged post-ischemic survival. We conducted 15-min four-vessel-occlusion ischemic episodes in rats, allowed these animals to survive for approximately 8 months and then examined the basic morphological features and population synaptic activities of CA3 neurons. In fixed tissue sections obtained from dorsal hippocampi of post-ischemic rats, we observed a complete loss of the CA1 neurons together with a shrunken CA1 sector. Extracellular recordings in slices revealed that the overall synaptic activities of dorsal hippocampal CA3 neurons were decreased in post-ischemic rats compared with sham-operated controls. Both sham control and post-ischemic ventral hippocampal neurons were capable of exhibiting intermittent spontaneous field potentials in slices. These spontaneous field potentials spread from the CA3 to the CA1 area and their generation relied on the activity of glutamate alpha-amino-3-hydroxy-5-methyl-4 isoxazole proprionic acid (AMPA) receptors. The propensity for displaying these spontaneous field potentials appeared to be greater in post-ischemic slices than sham control slices. Our data suggest that the hyper-excitability of the post-ischemic hippocampus, if it occurs, may preferentially take place in the ventral CA3 circuitry.

Preparation of new amino acid complex nanoparticles of bismuth and leucine

The new amino acid complex nanoparticles of bismuth and leucine can be prepared very easily by a room temperature solid-solid reaction. The various characterizations indicate that the formula of the complex is BiCl[(CH(3))(2)CHCH(2)CHNH(2)COO](2)1.5H(2)O. The crystal structure of the solid complex belongs to monoclinic system with the lattice parameters: a = 1.6036 nm, b = 1.9903 nm, c = 2.1979 nm and beta=108.06 degrees . The new solid complex is nanoparticles with average size about 80 nm.

Active dendrites and spike propagation in multi-compartment models of oriens-lacunosum/moleculare hippocampal interneurons

It is well known that interneurons are heterogeneous in their morphologies, biophysical properties, pharmacological sensitivities and electrophysiological responses, but it is unknown how best to understand this diversity. Given their critical roles in shaping brain output, it is important to try to understand the functionality of their computational characteristics. To do this, we focus on specific interneuron subtypes. In particular, it has recently been shown that long-term potentiation is induced specifically on oriens-lacunosum/moleculare (O-LM) interneurons in hippocampus CA1 and that the same cells contain the highest density of dendritic sodium and potassium conductances measured to date. We have created multi-compartment models of an O-LM hippocampal interneuron using passive properties, channel kinetics, densities and distributions specific to this cell type, and explored its signalling characteristics. We found that spike initiation depends on both location and amount of input, as well as the intrinsic properties of the interneuron. Distal synaptic input always produces strong back-propagating spikes whereas proximal input could produce both forward- and back-propagating spikes depending on the input strength. We speculate that the highly active dendrites of these interneurons endow them with a specialized function within the hippocampal circuitry by allowing them to regulate direct and indirect signalling pathways within the hippocampus.

GDNF acutely modulates excitability and A-type K(+) channels in midbrain dopaminergic neurons

Glial cell line-derived neurotrophic factor (GDNF) prevents lesion-induced death of midbrain dopaminergic neurons, but its function in normal brain remains uncertain. Here we show that GDNF acutely and reversibly potentiated the excitability of cultured midbrain neurons by inhibiting transient A-type K(+) channels. The effects of GDNF were limited to large, tyrosine hydroxylase (TH)-positive dopaminergic neurons, and were mediated by mitogen associated protein (MAP) kinase. Application of GDNF also elicited a MAP kinase-dependent enhancement of the excitability in dopaminergic neurons in midbrain slice. These results demonstrate an acute regulation of GDNF on ion channels and its underlying signaling mechanism, and reveal an unexpected role of GDNF in normal midbrain dopaminergic neurons.

Cytokine up-regulation in ischaemic/reperfused lungs perfused with University of Wisconsin solution and normal saline

Ischaemia/reperfusion (I/R) lung injury using University of Wisconsin solution (UW) as perfusate has not been well studied. Isolated rat lungs were challenged with various periods of ischaemia and/or reperfusion. Haemodynamics, lung weight gain (LWG), capillary filtration coefficient (K(fc)), tissue pathology, the concentrations of cytokines in the perfusate, and mRNAs for the various cytokines in the lung tissues were measured. I/R induced a permeability type of pulmonary oedema, as reflected by increases in LWG and K(fc). LWG and K(fc) in the I(45)R(60)(UW) group (45 min of ischaemia followed by 60 min of reperfusion with UW) were only 2% and 5% respectively of those in the I(45)R(60)(NS) group (where NS is normal saline). LWG and K(fc) in the UW group had both increased by 180 min, to values similar to those in the I(45)R(60)(NS) group. However, these findings show that UW was remarkably effective at preventing LWG after 60 min of reperfusion, and was more than 3-fold more effective than NS in delaying LWG. For longer ischaemic times only, or the same period of ischaemia followed by longer reperfusion periods, greater lung injury occurred. I/R lung injury also induced increased concentrations of tumour necrosis factor-alpha (TNF-alpha), interleukin 1 and interleukin 6 in the perfusate, and increased the mRNAs for these cytokines in lung tissue. A significant correlation was obtained between TNF-alpha concentration and LWG. TNF-alpha production in the I(45)R(60)(UW) group was only 7% of that in the I(45)R(60)(NS) group. However, TNF-alpha mRNA expression in the I(45)R(60)(UW) group was 80% of that in the I(45)R(60)(NS) group. This indicates that transcription/translation do not correlate well with cytokine production, and also suggests that one reason for the effectiveness of UW in delaying LWG may be because it delays TNF-alpha production. In summary, ischaemia or I/R caused a permeability-type pulmonary oedema that was associated with leucocyte infiltration and the up-regulation of various cytokines, regardless of the perfusion fluid. Except for pulmonary hypertension, less severe I/R lung injury and delayed cytokine production in lungs perfused with UW, the pattern of injury associated with I/R challenge was similar to that in lungs perfused with NS. We propose that more or long-acting protective agents are required as additives in order to modify UW to produce an optimal preservation solution.

Dexamethasone and pentastarch produce additive attenuation of ischaemia/reperfusion lung injury

The choice of an intravenous solution for the attenuation of ischaemia/reperfusion (I/R) lung injury is still a difficult one. Although 10% (w/v) pentastarch has been used in ICU settings, its use in I/R lung injury has not been well explored. We hypothesized that this synthetic colloid substance, which maintains colloid osmotic pressure and potentially 'seals' capillary leaks, in combination with an anti-inflammatory agent (i.e. dexamethasone), would ameliorate I/R lung injury. After 60 min of lung ischaemia in an isolated rat lung model, lungs were reperfused for 60 min in a closed circulating system with one of the following solutions: (1) NS (0.9% normal saline), (2) NS+Dex (dexamethasone), (3) NS+Penta (pentastarch), or (4) NS+Penta+Dex. Haemodynamic changes, lung weight gain (LWG), capillary filtration coefficient (K(fc)) and lung pathology were analysed. Results showed significantly lower values of K(fc) and LWG in pentastarch- or dexamethasone-perfused groups as compared with those in the NS group. Dexamethasone as an additive to NS+Penta further decreased K(fc) and LWG. Histopathological studies showed similar decreases in injury profiles. We conclude that reperfusion with dexamethasone and pentastarch can attenuate I/R lung injury, and that dexamethasone and pentastarch have additive effects. Our data thus suggest that the combination of a colloid substance with 'sealing effects' and an anti-inflammatory agent may provide a better reperfusion solution for patients with I/R lung injury or for lungs stored for transplant.

Use of anti-(tumour necrosis factor-alpha) antibody or 3-deaza-adenosine as additives to promote protection by University of Wisconsin solution in ischaemia/reperfusion injury

Experimental interventions that reduce ischaemia/reperfusion (I/R) lung injury can be used to improve the properties of preservation solutions. We attempted to increase the attenuation of I/R injury by University of Wisconsin solution (UW) by adding an antibody against tumour necrosis factor-alpha (TNF-alpha), to neutralize TNF-alpha, and/or by adding 3-deaza-adenosine (c3-Ado), to inhibit leucocyte adhesion and the biosynthesis of ICAM-1 (intercellular cell-adhesion molecule 1). We examined I/R injury using an isolated rat lung model. Six different solutions were perfused individually, followed by evaluation of I/R injury: (1) 0.9% NaCl (normal saline; NS), (2) NS+anti-TNF-alpha antibody, (3) UW alone, (4) UW+anti-TNF-alpha, (5) UW+c3-Ado and (6) UW+anti-TNF-alpha+c3-Ado. Haemodynamic changes, lung weight gain, capillary filtration coefficient, TNF-alpha levels and lung pathology were analysed in order to evaluate I/R injury. Compared with lungs perfused with NS, lungs treated with NS+anti-TNF-alpha showed less I/R injury. The addition of anti-TNF-alpha and/or c3-Ado to UW reduced I/R injury compared with unmodified UW. Among the six solutions tested, UW containing anti-TNF-alpha antibody reduced I/R injury to the greatest extent. We conclude that addition of anti-TNF-alpha antibody or c3-Ado protects against I/R lung injury when using UW. Further investigation of the improved properties of modified UWs would be beneficial with regard to lung transplantation research.

Effect of roxarsone inclusion in the diet on the performance and hepatic lipid metabolism of laying Tsaiya duck

1. The aim of this study was to examine the effects of roxarsone (3-nitro-4-hydroxyphenylarsonic acid) inclusion in the diet on the performance, liver function and lipid metabolism in the liver of laying Brown Tsaiya ducks. 2. Sixty 36-week-old laying ducks were selected and allocated at random into 4 dietary treatments with 3 replications for each treatment. Feeding was for 7 weeks with 3 weeks of experimental diets followed by a 4 week withdrawal period. The experimental diets were supplemented with 0, 50, 100 and 300 mg/kg roxarsone, respectively 3. Dietary inclusion of 50 or 100 mg/kg roxarsone did not significantly promote performance. Inclusion of 300 mg/kg significantly depressed (P<0.05) performance, liver weight and content, serum triacylglycerol (TG), serum nonesterified fatty acid (NEFA) and increased (P<0.05) cholesterol, creatine kinase (CK) and aspartate aminotransferase (AST) in the serum at the end of 3 weeks on the experimental diet. 4. Laying characteristics returned to normal 4 weeks after withdrawal of roxarsone. The liver weight, fat and TG in the liver and serum concentrations of TG, NEFA, high density lipoprotein (HDL) and AST increased significantly (P<0.05), while the level of very low density lipoprotein (VLDL) decreased (P<0.05) at the end of the withdrawal period. More prominent vacuolised hepatic fatty cells were observed in laying ducks treated with 300 mg/kg of roxarsone.

Hypothermia and prostaglandin E(1) produce synergistic attenuation of ischemia-reperfusion lung injury

Current methods of preserving lung tissue for transplantation are inadequate. In this study, we tested whether the combination of hypothermia plus prostaglandin E(1) (PGE(1)) treatment would have synergistic attenuation on ischemia-reperfusion (I/R) lung injury. Isolated rat lung experiments with ischemia for 1 h then reperfusion for 1 h, were conducted using six different perfusates: (1) University of Wisconsin solution (UW) at 30 degrees C (n = 5), (2) UW at 22 degrees C (n = 5), (3) UW at 10 degrees C (n = 4), (4) UW+PGE(1) at 30 degrees C (n = 4), (5) UW+PGE(1) at 22 degrees C (n = 4), and (6) UW+PGE(1) at 10 degrees C (n = 4). Hemodynamic changes, lung weight gain, capillary filtration coefficients, and lung pathology were analyzed to evaluate the I/R injury. Compared with 30 degrees C UW, animals treated with 22 degrees C UW and 10 degrees C UW had less I/R lung injury, with the groups receiving 22 degrees C UW showing superior results to group receiving 10 degrees C UW. The addition of PGE(1) to UW solution produced more attenuation of I/R injury than did UW alone. Among the six groups, 10 degrees C UW+PGE(1) produced the most reduction of I/R injury. This study has shown that hypothermia can attenuate I/R injury with the optimal flushing temperature being near 22 degrees C. PGE(1) also has a protective effect on I/R. Furthermore, hypothermia and PGE(1) have synergistic attenuation of I/R lung injury. We propose that pulmonary artery flushed with cooling UW+PGE(1) might improve lung preservation and improve results in lung transplantation.

Preamplifier with a second-order high-pass filtering characteristic

A new preamplifier for suppressing low-frequency interference is presented. The proposed preamplifier, with its front end being implemented by an instrumentation amplifier, enjoys the following advantages: differential high-pass filtering, high input impedance, high common--mode rejection ratio and low passive sensitivity. This circuit can be realized with commercial operational amplifiers with enough phase margin, or fabricated in a chip for practical measurement of physiological signals.

Long-term beta-blocker therapy improves autonomic nervous regulation in advanced congestive heart failure: a longitudinal heart rate variability study

BACKGROUND

beta-Blocker therapy is believed to modulate the detrimental effect of overcompensating neurohormonal activation in chronic heart failure. However, clinical doubts remain, particularly the physiologic sympathovagal balance.

METHODS

To respond to clinical concern about worsening autonomic nervous perturbation in beta-blocker therapy of advanced congestive heart failure, 15 consecutive patients were longitudinally studied to elucidate the evolution of cardiac function versus 24-hour heart rate variability (HRV) before and after 1, 3, and 6 to 9 months of atenolol-combined therapy.

RESULTS

Two patients died prematurely within 1 month. All 13 surviving patients showed improvement in New York Heart Association functional class, with decrease in left ventricular end-systolic and end-diastolic dimensions and increase in fraction shortening and ejection fraction by echocardiography after at least 3 months of atenolol use. The retarded therapeutic effect was accompanied by a general rise of total, very low, low-, and high-frequency components (9.0 +/- 0.5, 8.8 +/- 0.5, 6.2 +/- 0.6, and 6.1 +/- 0.5 vs 10.9 +/- 0.3, 10.7 +/- 0.4, 8.6 +/- 0.3, and 7.8 +/- 0.3; all P <.02) of daily HRV. This implied recovery of parasympathetic and baroreceptor function. Return of sympathovagal interaction was further supported by the suppression of Cheyne-Stokes type HRV as detected by Wigner-Ville distribution.

CONCLUSIONS

Long-term beta-blocker therapy for advanced congestive heart failure upwardly regulates the autonomic nervous interaction in synchrony with the evolution of cardiac function performance.

Slow oscillations (</=1 Hz) mediated by GABAergic interneuronal networks in rat hippocampus

Perfusion of rat brain slices with low millimole CsCl elicits slow oscillations of </=1 Hz in hippocampal CA1 pyramidal neurons. These oscillations are GABAA receptor-mediated hyperpolarizations that permit a coherent fire-pause pattern in a population of CA1 neurons. They can persist without the activation of ionotropic glutamate receptors but require adenosine-dependent inhibition of glutamate transmission. In response to external Cs+, multiple interneurons in the CA1 region display rhythmic discharges that correlate with the slow oscillations in CA1 pyramidal neurons. The interneuronal discharges arise spontaneously from the resting potential, and their rhythmicity is regulated by periodic, GABAA receptor-mediated hyperpolarizations. In addition, interneurons show periodic partial spikes and neurobiotin coupling, and applications of known gap junctional uncouplers interrupt the Cs+-induced slow rhythm in both CA1 pyramidal neurons and interneurons. We propose that these slow oscillations originate from a GABAergic interneuronal network that interacts through reciprocal inhibition and possibly gap junctional connection.

Protective agents used as additives in University of Wisconsin solution to promote protection against ischaemia-reperfusion injury in rat lung

1. An intervention to reduce ischaemia-reperfusion lung injury will be an important advance in transplant medicine. Although the mechanisms associated with producing ischaemia-reperfusion endothelial injury have not been completely elucidated, many of the injury mediators have been studied in detail. While no single pharmacological therapy is likely to be totally effective in eliminating this complex injury, we have developed a mixture of agents that are known to block pathways involved in producing ischaemia-reperfusion-associated lung vascular injury.2. The present study modified University of Wisconsin solution (UW) by adding one of the protective agents prostaglandin E1 (PGE1), dexamethasone (Dex) or dibutyryl cAMP (Bt2-cAMP), or a combination of these, to the perfusate of rat lungs exposed to 4 h of cold ischaemia followed by 1 h of reperfusion. Nine modified UW solutions were studied: (1) UW+Dex, (2) UW+PGE1, (3) UW+Bt2-cAMP, (4) UW+Dexx3, (5) UW+PGE1x3, (6) UW+Bt2-cAMPx3, (7) UW+Dex+PGE1, (8) UW+Dex+Bt2-cAMP, (9) UW+PGE1+Bt2-cAMP. These solutions were utilized in individual experiments to assess haemodynamic changes, lung weight gain, the capillary filtration coefficient (Kfc) and pathology in all lungs.3. The results indicate that lung weight gain and Kfc values were significantly lower than with UW alone in groups 1, 2 and 3, which contained only one additional protective agent. In groups 4, 5 and 6, which contain three times the concentration of each protective agent, both Kfc and lung weight gain were similar to those measured in groups 1, 2 and 3, i.e. lungs were protected but the protection was not dose dependent. In groups 7, 8 and 9, which contained two protective agents, lung weight gain and Kfc were greatly reduced compared with UW alone. Histopathological studies showed similar decreases in the injury profiles of lungs.4. Although UW contains several antioxidant protective agents such as allopurinol and glutathione, it did not provide effective protection in our ischaemia-reperfusion lung injury model. UW modified with an additive of PGE1, Dex or Bt2-cAMP attenuated ischaemia-reperfusion injury. Furthermore, UW containing two of these protective agents augmented the protection. Among the modified solutions, it appears that UW+PGE1+Bt2-cAMP protects the lungs to a greater extent than all other solutions used in our study. We suggest that preservation solutions containing PGE1-Bt2-cAMP will provide additional protective effects to organs stored for transplantation.

Time-frequency spectral analysis of heart rate variability during induction of general anaesthesia

We have examined the spectral components of heart rate variability (HRV) during induction of anaesthesia with thiopentone, tracheal intubation and subsequent inhalation of isoflurane-nitrous oxide. Commonly used spectral analysis methods such as fast Fourier transformation or autoregressive modelling require stationary data and are not suitable for the rapidly changing HRV data in this period. An advanced spectral analysis method, time-frequency analysis, which can treat non-stationary data, was used in this study. Multiple spectra were generated to demonstrate the time-related spectral components of HRV. Mid-frequency power (MF, 0.08-0.15 Hz), high-frequency power (HF, 0.15-0.5 Hz) and MF/HF ratio at baseline, after induction (before intubation), immediately after intubation and during maintenance periods were calculated and compared. MF and HF powers decreased after induction and were reduced further in the maintenance period but MF/HF ratio remained unchanged after induction. Immediately after intubation MF and HF powers did not differ significantly from the immediate pre-intubation values, but MF/HF ratio did.

Elimination of interference component in Wigner-Ville distribution for the signal with 1/f spectral characteristic

A new technique for interference-term suppression in Wigner-Ville distribution (WVD) is proposed for the signal with 1/f spectrum shape. The spectral characteristic of the signal is altered by f alpha filtering before time-frequency analysis and compensated after analysis. With the utilization of the proposed technique in smoothed pseudo Wigner-Ville distribution, an excellent suppression of interference component can be achieved.

Time-frequency distribution of heart rate variability below 0.05 Hz by Wigner-Ville spectral analysis in congestive heart failure patients

The Wigner-Ville spectral analysis was utilized to demonstrate a high-resolution time-frequency distribution of heart rate variability below 0.05 Hz. There are different time-frequency characteristics between the normal subject and the patient with severe congestive heart failure. The former consists of multiple and broad-band spectral peaks, while the latter presents unique spectral peaks. Based on Bayes theory, a classifier for the unique spectral peaks was developed. After the beneficial improvement with low-dose beta-blockers, the unique spectral peaks had disappeared or the time of occurrence was reduced in most patients.

Analog transmission line model for simulation of systemic circulation

A simple four-tube arteries-microvessels-veins system which simulates a more realistic loading for human circulation was built using transmission line network. Hemodynamic data from literature are used in the fluid-circuit analogy, and the flow leakage and viscoelastic properties of the blood vessels have been considered. The effect of veins on the input impedance spectrum was found to be negligibly small above 0.5 Hz. The predicted input impedance spectra agree reasonably well with the published measurements both in shape and magnitude. Parametric analysis shows that the changes of vascular properties in the lower body affect the first minimum, and the changes in the upper body influence the second minimum. The blood flow in and out of kidney and liver dominates the aortic impedance from 0 to 5 Hz. Decreasing capacitance (i.e., increasing arterial stiffness due to aging), reducing the lumen area, or decreasing the length of blood vessels result in an increase in the impedance modulus, and the first minimum shift to a higher frequency which agree well with experiments. In the current model, the pressure, flow waveform, and local impedance can be predicted at any location along the circulatory tree. The characteristic of arterial pulse propagation resembles published measurements.

Pulmonary edema induced by phorbol myristate acetate is attenuated by compounds that increase intracellular cAMP

We have investigated the effect of terbutaline, aminophylline and dibutyryl cyclic AMP (DBcAMP) on phorbol myristate acetate (PMA)-induced acute lung injury in isolated, blood-perfused rabbit lungs. Pulmonary arterial pressure and lung weight were measured for 30 min after a bolus injection of PMA (10 mu g/kg). In the group exposed to PMA alone, the mean pulmonary arterial pressure (PAP) increased from 16.33 + or - 1.28 to 77.30 + or - 6.40 mmHg (P <0.001), and lung weight increased by 70.69 + or - 10.94 g during the 30 min after PMA challenge (P<0.001). Pretreatment with terbutaline, aminophylline or DBcAMP prevented the increases in both PAP and lung weight (P <0.001). Each of the three drugs also prevented the increase in pulmonary vascular permeability induced by PMA: terbutaline, aminophylline, and DBcAMP all significantly reduced the pulmonary capillary filtration coefficient (KfC) as well as the albumin concentration in the lung lavage fluid after PMA exposure. Post-treatment with terbutaline 5 min after PMA administration also had a protective effect. The mechanisms responsible for these protectivp3 effects may all involve an increase in intracellular cAMP, since all three drugs increase cAMP in the lung (though by different mechanisms). Our data further indicate that the inhibition of tumor necrosis factor production may likewise play an important role in the protective effect exerted by these drugs.

Different mechanisms underlying the repolarization of narrow and wide action potentials in pyramidal cells and interneurons of cat motor cortex

Two different types of action potentials were observed among the pyramidal cells and interneurons in cat motor cortex: the narrow action potentials and the wide action potentials. These two types of action potentials had similar rising phases (528.8 +/- 77.0 vs 553.1 +/- 71.8 mV/ms for the maximal rising rate), but differed in spike duration (0.44 +/- 0.09 vs 1.40 +/- 0.39 ms) and amplitude (57.31 +/- 8.22 vs 72.52 +/- 8.31 mV), implying that the ionic currents contributing to repolarization of these action potentials are different. Here we address this issue by pharmacological manipulation and using voltage-clamp technique in slices of cat motor cortex. Raising extracellular K+ concentration (from 3 mM to 10 mM), applying a low dose of 4-aminopyridine (2-200 microM) or administering a low concentration of tetraethylammonium (0.2-1.0 mM) each not only broadened the narrow action potentials, but also increased their amplitudes. In contrast, high K+ medium or low dose of tetraethylammonium only broadened the wide action potentials, leaving their amplitudes unaffected, and 4-aminopyridine had only a slight broadening effect on the wide spikes. These results implied that K+ currents were involved in the repolarization of both types of action potentials, and that the K+ currents in the narrow action potentials seemed to activate much earlier than those in the wide spikes. This early activated K+ current may counteract the rapid sodium current, yielding the extremely brief duration and small amplitude of the narrow spikes. The sensitivity of the narrow spikes to 4-aminopyridine may not be mainly attributed to blockade of the classical A current (IA), because depolarizing the membrane potential to inactivate IA did not reproduce the effects of 4-aminopyridine. Blockade of Ca2+ influx slowed the last two-thirds repolarization of the wide action potentials. On the contrary, the narrow action potentials were not affected by Ca(2+)-current blockers, but if they were first broadened by 4-aminopyridine or tetraethylammonium, subsequent application of Ca(2+)-free medium caused further broadening, suggesting that the narrow action potentials were too brief to activate the Ca(2+)-activated potassium currents for their repolarization. Therefore, the effects of low concentrations of tetraethylammonium on the narrow spikes appeared to be mainly due to blockade of an outward current that was different from the tetraethylammonium-sensitive Ca(2+)-activated potassium current (IC). In the neurons with the narrow spikes, voltage-clamp experiments revealed two voltage-gated outward currents that were sensitive to tetraethylammonium and 4-aminopyridine, respectively. Both currents were activated rapidly following the onset of depolarizing steps. Interestingly, the tetraethylammonium-sensitive current was a transient outward current that inactivated rapidly (tau < or = 5 ms), while the 4-aminopyridine-sensitive current was relatively persistent during maintained depolarization. The 4-aminopyridine-sensitive current did not show obvious inactivation even at membrane potential of -40 mV, which completely inactivated the transient tetraethylammonium-sensitive, current. The results indicate that different potassium currents are involved in the repolarization of the narrow and wide action potentials in cat motor cortex. A novel tetraethylammonium-sensitive transient outward current and a 4-aminopyridine-sensitive outward current are responsible for the short duration and small amplitude of the narrow action potentials in the interneurons and some of the layer V pyramidal cells. These two currents are voltage-gated and Ca(2+)-independent. For the wide action potentials that characterize most pyramidal neurons, a Ca(2+)-independent tetraethylammonium-sensitive outward current and a Ca(2+)-activated potassium current are the main contributors to their repolarization.

Electrophysiological and morphological properties of pyramidal and nonpyramidal neurons in the cat motor cortex in vitro

Electrophysiological and morphological properties of the neurons in cat motor cortex were investigated using intracellular recording and staining techniques in a brain slice preparation. In response to intracellular injection of depolarizing current pulses, four distinct types of firing patterns were observed among cat neocortical neurons. Regular-spiking neurons were characterized by their repetitive firing from which conspicuous frequency adaptation was observed. Doublet-or-burst firing cells were marked with their tendency to fire 2-5 clustered spikes at the onset of depolarizing pulse. In doublet-or-burst firing neurons, but not in regular-spiking neurons, a low-threshold calcium current was revealed by single-electrode voltage clamp. Both regular-spiking and doublet-or-burst firing neurons had relatively wide action potentials. Fast-spiking neurons could fire extremely narrow action potentials at a very high frequency. Their frequency-to-intensity slope of steady-state firing was significantly higher than that of the other neurons. In contrast, narrow-spiking neurons had the smallest frequency-to-intensity slope for steady-state firing, although their action potentials were as narrow as those of the fast-spiking neurons. Both regular-spiking and doublet-or-burst firing neurons were identified as pyramidal neurons, and were found in all layers below layer I. Their apical dendrites were densely coated with dendritic spines. Narrow-spiking neurons were only recorded in layer V. They were large pyramidal cells with scare spines on their apical dendrites. Fast-spiking neurons were all nonpyramidal interneurons. Seven out of eight labelled fast-spiking cells had beaded dendrites without spines. Their axons had a large number of varicosities, and arborized extensively to form a dense plexus of terminals in the vicinity of their soma. The remaining neuron was found to be a spiny nonpyramidal neuron in layer V. These results demonstrate that, in addition to the three types of firing patterns previously identified in rodent neocortex, a group of neurons in the cat motor cortex express another type of firing behaviour which is characterized by extremely narrow action potential and very small frequency-to-intensity slope. Correlation with the morphological data shows that these neurons are large layer V pyramidal cells rather than nonpyramidal interneurons.

GABAA receptor-mediated feedback inhibition in pyramidal neurons of cat motor cortex

Feedback or recurrent inhibition is generally proposed as a basic component of circuit organization in the brain. However, there is little direct evidence for its existence in the cortex, nor for the nature of the neurotransmitters and receptors involved. Here we address this issue by analyzing the potentials following a single action potential in cat neocortical pyramidal neurons. Using 3 M KCl-filled electrodes, we observed a distinct depolarizing potential that was superimposed on the spike after-potentials in seven out of 81 recorded and the resemblance between its falling phase and the passive decay of membrane potential suggested that the depolarizing potential originated from the cell body or proximal dendrites. This potential was blocked by bicuculline methiodide (10 microM), but not by phaclofen (0.2 mM), suggesting that it was a reversed recurrent IPSP mediated by GABAA receptors.

Two mechanisms underlying the induction of long-term potentiation in motor cortex of adult cat in vitro

Long-term potentiation of synaptic transmission (LTP), as documented by the enhancement of evoked field potentials in layer III following stimulation of the underlying white matter, has been studied in slices of motor cortex from adult cats. With a 1 M NaCl-filled recording electrode, LTP was induced only in one out of eight slices. When the recording electrode in addition contained 5 mM bicuculline metiodide, LTP was obtained with a much higher rate of success (15/19), suggesting that reduction of GABAA receptor-mediated inhibition facilitated the induction of LTP in the motor cortex. Bath application of DL-2-amino-5-phosphonovaleric acid (APV, 100 microM) or Ni2+ (100 microM) significantly reduced the success rate for LTP occurrence (6/16 and 5/16, respectively); but when LTP was induced, it did not show significant change in magnitude and time course. In slices perfused with APV (100 microM) plus Ni2+ (100 microM), LTP induction was completely blocked (0/12). These results suggest that two different mechanisms may subserve LTP induction in the cat motor cortex: one is mediated by N-methyl-D-aspartate receptors and can be blocked by APV; the other may be mediated by low-threshold calcium channels and can be blocked by Ni2+.

Adult respiratory distress syndrome caused by pulmonary cryptococcosis in an immunocompetent host: a case report

The development of adult respiratory distress syndrome (ARDS) can be associated with a variety of clinical disorders. Pulmonary cryptococcosis occurring in immunocompromised patients has been reported with increasing frequency because of the rapidly rising number of immunocompromised hosts and the improvement in diagnostic techniques. But pulmonary cryptococcosis causing ARDS in immunocompetent patients has not, to present knowledge, been described. Here a rare case of pulmonary cryptococcosis is reported in an immunocompetent host who developed adult respiratory distress syndrome. The clinical course, radiologic patterns, methods of diagnosis and treatment are reviewed.

Distribution of synapses on an intracellularly labeled small pyramidal neuron in the cat motor cortex

The morphological characteristics and distribution of synapses on a small pyramidal neuron in layer III of the cat motor cortex have been studied by combining intracellular HRP staining and electron microscopic examination. The stained neuron showed spiny apical and basal dendritic profiles under the light microscope, and exhibited the morphological features of a pyramidal neuron. Ultrastructural analysis indicated that about 80% of the presynaptic terminals formed asymmetrical synapses with spines of distal apical and basal dendrites. On proximal apical dendrites, 64% of the synapses were found to make contact with spines, and 16.7% of the synapses were of symmetrical type and formed with dendritic shafts. Two types of terminal could be identified on the soma; they were alternately located and established symmetrical and asymmetrical synaptic contacts respectively. Possible functional implications are discussed.

Distribution of synapses on fast and slow pyramidal tract neurons in the cat. An electron microscopic study

Distributions of synapses on various portions of fast and slow pyramidal tract neurons (PTNs) in cat motor cortex were studied with electron microscopy. PTNs were identified by their antidromic invasion following stimulation of the medullary pyramid and were classified into fast and slow PTNs according to conduction velocities of their axons. Two fast and two slow PTNs were intracellularly labeled and, by systematic sampling, electron micrographs from various portions of these neurons were examined to compare the distributions of different types of synapses. It was found that most synapses formed on apical and basal dendrites of fast PTNs were with the dendritic shafts. In slow PTNs, while synapses on apical dendrites were mostly axospinous, about 70% of the sampled synapses on basal dendrites of slow PTNs were established with the dendritic shafts. Virtually all synapses on apical dendrites of slow PTNs belonged to asymmetrical type and most of the synapses sampled from basal dendrites of fast PTNs were also asymmetrical. On the other hand, about 29% of the synapses found on apical dendrites of fast PTNs were symmetrical and a trend was observed for this type of synapses to increase their number with increasing proximity to the cell body. Over 28% of the synapses on basal dendrites of slow PTNs were also symmetrical and seemed to be mainly distributed in layer VI. All synapses formed on the soma were symmetrical both for the fast and slow PTNs.

Multi-organ involvement in urothelial malignancies

The present study covers 1213 patients with urothelial tumours, of whom 113 have been affected by multi-organ malignancies. The disease was found to spread mostly in direction of the urine flow. Bladder was the most frequently affected organ. The incidence of pelvic cancer in China is higher than in Western countries.

Vicissitude of management of ureteral stones

Following the use of rigid ureteroscopic lithotripsy (URS) in 1984 and extracorporeal shock wave lithotripsy (ESWL) in 1987, the treatment for ureteral stones has undergone significant changes. Our experience showed that the successful rate of URS for 132 patients was 89.4% and for the upper third was rather low, percutaneous antegrade URS should be considered. 376 patients treated with ESWL in prone position with a successful rate of 96.8%. The applicability of open surgery was reduced to 17.8% in 1987 and 14.5% in 1988.

Age factor in post-nephrectomy compensatory renal growth

In a retrospective investigation we found that the endogenous creatinine clearance (Ccr) of 35 nephrectomized patients was lower than that of normal people of comparable age with two intact kidneys. The Ccr level in the post-nephrectomy patients appeared to correlate with the age of the patients at the time of nephrectomy. The average Ccr value was 99.2 ml/min in the younger group, and 54.9 ml/min in the older group. Furthermore, we also found that the measurement of the remaining kidney in the younger group was larger than that of the matched control group, but no difference was found between the measurement of the remaining kidney in the older group and that of the matched control group. Therefore, we suggest that the remaining kidney in patients over 50 years of age may be described as "a low compensatory kidney". The results from an experimental study of Wistar rats indicated that the dry and wet weights of the remaining kidneys of the younger rats which had undergone neptrectomy were 1.53 X 10(-3) g/gwt, and 5.89 X 10(-3) g/gwt respectively, vs 1.05 X 10 g/gwt and 3.82 X 10(-3) g/gwt in older ones. In tissue culture using serum of younger nephrectomized rats, the amount of 3H-TdR incorporation into the monolayer cells of renal cortex was 1,405.4 CPM, whereas it was 1,025.4 CPM by using serum of older nephrectomized rats. In addition, the cells of renal cortices from both younger and older rats had a similar response to the same serum from nephrectomized rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[The measurement of airway responsive index in normal individuals and asthmatic patients]

Measurement of airway responsiveness to nonallergenic stimuli can be used to confirm the diagnosis of asthma, document the severity of airway responsiveness, and follow changes in airway responsiveness with time in relation to treatment or exposure to occupational sensitizers. Methacholine inhalation is the preferred test for the clinical laboratory as it is more sensitive than exercise or cold air, and there are fewer side effects than with histamine. Airway responsiveness to nonspecific, pharmacologic, bronchoconstricting stimuli has been described using various methods of summarizing dose-response data. The purpone of this study was to examine a simple index of nonspecific airway responsiveness to methacholine, i.e., the slope of a straight line approximation of the dose-response curve. Twelve normal and 19 asthmatic volunteers were studied. Subjects underwent a standard methacholine challenge test, both specific airway conductance (SGaw) and forced expiratory volume of one second (FEV1) were measured. We examined the relationship between response assessed by SGaw or FEV1 and dose of methacholine in each subject. The results showed that, in most of the subjects, the decline of pulmonary function with increasing dose of methacholine almost followed a simple linear relationship. A straight line extending from the origin to the last data point obtained approximating this relationship provides a reasonable summary of each plot. This were true not only in asthmatic subjects but also in normals, and not only for FEV1 but also for SGaw. The slope of this straight line was denominate as responsive index. The summary dose-response slope effectively separated asthmatic from normal subjects without any overlapping; this was true not only when FEV1 but also for SGaw was used as the parameter of response. The responsive index was much greater among asthmatics than among normal subjects (P less than 0.001). The responsive index from the parameter of SGaw was nearly perfectively correlated with which was from FEV1 (r = 0.989, P less than 0.001). We considered that airway responsive index can be calculated not only when FEV1 but also SGaw was used as a parameter of pulmonary function response. The dose-response slope calculated in the present analysis is a summary of the overall dose-response relationship and thus differs from the slope of the latter part of the log dose-response curve. It has the advantage of providing a single, continuous, easily interpreted measure of responsiveness for all subjects.(ABSTRACT TRUNCATED AT 400 WORDS)

Thalamic projection to motor area and area 3a of the cat cerebral cortex

The distributions of thalamic neurons projecting to the motor cortex and cortical area 3a were studied in cat by means of the retrograde double-labeling technique using Nuclear Yellow (NY) and Fast Blue (FB) as tracers. Following injection of NY and FB into the motor cortex and area 3a respectively, the NY-labeled neurons were found to be mainly located in ventrolateral (VL) nucleus and FB-labeled neurons in ventro-posterolateral nucleus (VPL). However, these two kinds of neurons were intermingled with each other in the border area between VL and VPL. A small number of neurons were double-labeled by both NY and FB. They were also distributed in the border area. Some of them could often be found in centromedian and parafascicular nuclei.