Nitric oxide acts directly in the presynaptic neuron to produce long-term potentiation in cultured hippocampal neurons

Nitric oxide (NO) has been proposed to act as a retrograde messenger during long-term potentiation (LTP) in the CA1 region of hippocampus, but the inaccessibility of the presynaptic terminal has prevented a definitive test of this hypothesis. Because both sides of the synapse are accessible in cultured hippocampal neurons, we have used this preparation to investigate the role of NO. We examined LTP following intra- or extracellular application of an NO scavenger, an inhibitor of NO synthase, and a membrane-impermeant NO donor that releases NO only upon photolysis with UV light. Our results indicate that NO is produced in the postsynaptic neuron, travels through the extracellular space, and acts directly in the presynaptic neuron to produce long-term potentiation, supporting the hypothesis that NO acts as a retrograde messenger during LTP.

The optimal tidal volume delivered by ventilator after pulmonary resection: its effect on cardiopulmonary hemodynamics

Pulmonary function and gas exchange deteriorate after pulmonary resection. The vital capacity, tidal volume, and functional capacity decrease after pulmonary resection because of loss of effective lung volume and, therefore, affect the setting of the ventilator. Nineteen patients undergoing pulmonary resection were included in this study on the optimal tidal volume delivered by a ventilator. Five patients received mediastinal surgery or wedge resection of the lung, 4 had pneumonectomy, and 10 had lobectomy. Immediately after the pulmonary surgery, they were maintained with ventilatory support. Subsequently, a different setting of tidal volume on the ventilator was given for each patient, i.e., 6 ml/kg, 8 ml/kg, 10 mg/kg, and 14 ml/kg. For each setting of tidal volume, a hemodynamic study was performed including cardiac output and other parameters. With the examination of Wilk's Lambda test, there was no difference in association with different settings of tidal volume on blood pressure (F = 0.92, p = 0.51), pulmonary artery pressure (F = 0.95, p = 0.43), pulmonary vascular resistance (F = 0.24, p = 0.97), systemic vascular resistance (F = 0.42, p = 0.78), and cardiac output (F = 0.35, p = 0.93) in 3 different groups of patients. It is concluded that after pulmonary resection a patient's lungs can be inflated with a tidal volume to 14 ml/kg during ventilatory support without compromise of cardiovascular performance.

Organ transplantation in Taiwan

We performed the first successful kidney transplantation in Taiwan on May 27, 1968. Since then, kidney, heart, lung, pancreas, liver, and heart-kidney transplantations have been increasingly successful in restoring lives of otherwise dying patients with organ failure. The first successful kidney, liver, and heart transplantations in Asia were achieved in Taiwan in 1968, 1984, and 1987. respectively. Individual organ transplantation, organ transplant recipient survival, graft survival, and problems and pitfalls encountered in the care of organ transplantation recipients are analyzed. Using polymerase chain reaction amplification with sequence-specific primers, donor-specific DNA was detected in the peripheral blood of the patient who survived the longest (26 years) in this series. Interestingly enough, recently, we had a patient undergoing cadaveric renal transplantation in whom chimerism was detected in her lymph nodes and skin only 3 years after transplantation. Organ procurement in Taiwan is the greatest problem, and we have been exerting our maximal effort to establish a transplantation coordination team to create a central network and to educate, procure, preserve, distribute, and increase the availability of organs and tissues for transplantation.

Using titanium plate or meshplate for chest wall reconstruction: report of 6 cases and literature review

Titanium plate has been widely used in several surgical fields, such as craniofacial reconstruction and orthopedic prosthesis. This prosthesis has been proved not only with good biocompatibility and mechanical strength, but also with light weight and low radiological interference. From October 1991 to May 1995, 6 patients underwent thoracic cage reconstruction with titanium plate in our hospital. They included 5 females and 1 male, with ages ranging from 26 to 62 years. Four of them suffered from primary chest wall tumors (2 desmoid tumors, a chondrosarcoma, and 1 hemangioma), one had a recurrent chest wall tumor from breast carcinoma, and one had thoracic hypoplasia. The thoracic cage defect ranged from 5 x 6 cm to 10 x 15 cm, and 1 to 3 titanium plates were used for the reconstruction. No paradoxical movement or other prosthesis-related complications have occurred during the follow-up period. We conclude that titanium plate is a good material for thoracic cage reconstruction.

Production, binding characteristics and protective immunity of monoclonal antibody to pneumococcal type-9V conjugate

A monoclonal antibody (MAb) to pneumococcal type-9V polysaccharide (PS) was produced using PS conjugated to inactivated pneumolysin as the immunogen. The MAb to 9V PS was of the IgG1 subclass. The antigen-antibody reaction increased rapidly at low concentrations and reached a plateau at 10 micrograms PS/ml as measured by nephelometry of the group 9 PS against 9V MAb binding. In contrast, the binding of group 9 PS against rabbit 9V antiserum (AS) increased proportionally and continued to increase up to the highest concentration of PS tested (20 micrograms PS/ml). The 9V MAb reacted with all group 9 PSs (9A, 9L, 9N and 9V) by immunodiffusion. In the homologous 9V Ag-MAb reaction, there were marked differences in the inhibition of binding by the cross-reactive 9L PS (19.2% inhibition) and the 9N PS (0.2%). In contrast, inhibition of the homologous 9V Ag-rabbit AS binding by cross-reactive 9L and 9N PSs ranged from 57.8 to 62.7%. Removal of the O-acetyl group from 9V PS by alkali hydrolysis resulted in decreased binding with rabbit 9V AS. However, the binding reaction with 9V MAb was less affected by the loss of O-acetyl content. The 9V MAb was both opsonic and passively protected young mice against challenge with type-9V pneumococci.

The role of video-assisted thoracic surgery in the diagnosis and treatment of indeterminate pulmonary lesion

Patients with indeterminate pulmonary lesions usually require a definite diagnosis for proper management. The conventional diagnostic procedures such as bronchoscopy and transthoracic needle biopsy sometimes fail to obtain a decisive answer, thus a more aggressive diagnostic procedure will be needed. Video-assisted thoracic surgery (VATS) has provided an alternative for open thoracotomy for definite diagnosis in these conditions. Thirty-three patients with indeterminate pulmonary lesions received VATS in National Taiwan University Hospital. Of these patients, twenty-eight manifested with coin lesion and five had diffuse pulmonary infiltration before operation. Traditional diagnostic procedures, i.e. bronchoscopy or transthoracic needle biopsy, could not give a definite diagnosis for these patients. A definite diagnosis was obtained after thoracoscopy in all of these patients. The mean operation time was 129 minutes (range, 180 to 45 minutes). The mean duration of chest tube drainage was 4.1 days (range, 1 to 7 days). The mean postoperative hospital stay of elective surgery without subsequent chemotherapy or radiotherapy was 9.5 days (range, 5 to 14 days). The patients received 2.4 times parental narcotics injection for analgesia on average (range, 0 to 6 times). There is no operation-related death in this series. Three patients had prolonged air leak with seven days of chest tube drainage. Two patients, with CMV and chronic interstitial pneumonia, have mortality from their underlying disease later. VATS is a safe and effective procedure not only for diagnosis, but also for treatment in the management of indeterminate pulmonary lesions.

Videothoracoscopic treatment of spontaneous pneumothorax

Thoracoscopic surgery has been well accepted as a treatment for spontaneous pneumothorax and other intrathoracic diseases. Seventy-four patients with primary or secondary pneumothorax underwent thoracoscopic operation in this hospital. There was no postoperative mortality or major morbidity. Only two (2.7%) patients developed recurrent pneumothorax postoperatively, but this never reappeared after using bullae resection and mechanical pleurodesis in place of electroablation only at an earlier period. Three patients had residual pleural effusion or air space, and two patients had persistent air-leak postoperatively; all of them recovered after conservative treatment. The mean operation time, intensive care unit stay, and total hospital stay were decreased significantly when compared with open thoracotomy. The low recurrence rate and shorter hospital stay also made this procedure much superior to tube thoracostomy and chemical pleurodesis only. Approaches to make working ports, bullectomy, and pleurodesis are also discussed here. We concluded that thoracoscopic surgery is highly effective and minimally invasive for patients with spontaneous pneumothorax, but may not be suitable for patients with generalized emphysematous change of lungs or dense adhesion of the pleural spaces.

Nucleolar organizer regions as a prognostic factor in surgically treated lung cancer patients

The prognostic value of the number of nucleolar organizer regions (NORs) (DNA loops in the nucleus) in tumor cells from various kinds of malignancies has been widely studied in recent years. During the period 1989 to 1992, a total of 73 primary lung tumors was examined for the number of NORs by silver staining AgNOR proteins on the stump smear of resected specimens in this hospital. The relations of the mean number of AgNOR per cell with other factors such as sex, age, habit of smoking, performance status, tumor location, tumor size, pathological stage, histological type, degree of differentiation, and whether histologically vascular or lymphatic invasion were analysed. It was found that the mean number of AgNOR was significantly different between positives and negatives of histologically vascular or lymphatic invasion (6.4 +/- 0.4 vs 5.5 +/- 0.2) (p < 0.05). Both single and multiple-variate analysis of patient survival revealed that the mean number of AgNOR was a significant prognostic factor, as were pathological stage, histological type, and performance status of the patient. Patients with a higher mean number of AgNOR (> 7) had a significantly worse prognosis compared with those with less AgNOR (< or = 7) (median survival 28 versus 43 months) (p < 0.05). It was concluded that the mean number of AgNOR of tumor cells is a significant prognostic factor in surgically treated lung cancer patients.

Synaptic strengthening through activation of Ca2+-permeable AMPA receptors

Postsynaptic Ca2+ elevation during synaptic transmission is an important trigger for short- and long-term changes in synaptic strength in the vertebrate central nervous system. The AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate) receptors, a subfamily of glutamate receptors, mediate much of the excitatory synaptic transmission in the brain and spinal cord. It has been shown that a subtype of the AMPA receptor is Ca2+-permeable and is present in the subpopulations of neurons. When synaptically localized, these receptors should mediate postsynaptic Ca2+ influx, providing a trigger for changes in synaptic strength. Here we show that Ca2+-permeable AMPA receptors are synaptically localized on a subpopulation of dorsal horn neurons, and that they provide a synaptically gated route of Ca2+ entry, and that activation of these receptors strengthens synaptic transmission mediated by AMPA receptors. This pathway for postsynaptic Ca2+ influx may provide a new form of activity-dependent modulation of synaptic strength.

Meal skipping patterns and nutrient intakes of rural southern elderly

Dietary practices, a 24-hr food recall, self-reported health status, perceived well-being, and socioeconomic data were collected from 2890 rural elders selected from 11 southern states by a stratified randomization method based on income and population. Overall nutrient intakes were low, especially energy and calcium, and 16.3% of respondents consumed fewer than three meals daily. Though meal skippers snacked more frequently, their nutrient intakes were significantly lower than those of three-meal eaters. Meal skippers were more likely to be smokers, younger elders, females, those who ate alone and those with less education, higher BMI, and lower self-rated quality of well-being, especially economic and social well-being.

Simulation of oxygen saturation of hemoglobin solution, RBC suspension and hemosome by a neural network system

Hemoglobin-based artificial blood substitutes as oxygen carrier is advantageous over current plasma expander. In this study, oxygen saturation of hemoglobin solution, red blood cell suspension and artificial blood substitute under various conditions were measured by yeast-consuming-oxygen experiments instead of spectrophotometer. The empirical results were assigned into training feedforward back-propagation neural network system in order to simulate the oxygen saturation model modulated by those factors such as pH, [Cl-], [2,3-DPG], pO2 and pCO2. Consequently, this neural network is able to simulate accurately the oxygen saturation of Hb solution. The prediction of hemosome is not agreed well possible because of the resistance of transport of oxygen. However, the results showed neural net can offer a simple and convenient way in comparison with the conventional methods, especially in dealing with complex and ambiguous problem.

Fast and slow gating types of SR ryanodine receptor/channel purified from canine latissimus dorsi muscle

The ryanodine receptor/channel (RyR) mediates the release of calcium from the sarcoplasmic reticulum (SR) in both skeletal and cardiac muscle cells. There are three isoforms of the RyR: RyR1, RyR2, and RyR3. RyR1 is specifically expressed in skeletal muscles and RyR2 in cardiac muscles. RyR3 is yet another isoform found in non-muscle cells such as neuronal cells. Single channel recordings of RyR1 and RyR2 reconstituted in artificial lipid bilayer show that the characteristics of two isoforms are very distinct. RyR1 has a shorter mean open time and is activated at a higher concentration of Ca2+ than RyR2. In this study, we isolated the heavy SR membranes from canine latissimus dorsi muscles and investigated the single channel activities from the heavy SR membrane fraction using Cs+ as a charge carrier. Two different types of activities were observed. The fast-gating type (FG) with the mean open time of 0.9 ms was more frequently recorded (n = 12) than the slow-gating type (SG) with the mean open time of 269.2 ms. From the I-V relation, the slope conductance of the FG was calculated to be 514.7 pS and the SG, to 625.6 pS. The activity of the fast gating type increased by raising the concentration of Ca2+ in the cis-solution up to 100 microM. The appearance of the SG in the canine heavy SR membrane fraction suggests a possibility that two types of RyR isoform are co-expressed in mammalian skeletal muscle as well as in avian, amphibian and piscine fast twitch muscles.

Identification of malnutrition-related diabetes mellitus among hospitalized patients in Taiwan

A retrospective review of 1,089 diabetes mellitus admitted to the metabolic ward of Chang Gung Memorial Hospital was performed to screen for malnutrition-related diabetes mellitus (MRDM). None of the patients fulfilled the MRDM criteria, although 20 patients with a body mass index < or = 15 kg/m2 were further analyzed. These patients presented with poor glycemic control and most had associated chronic diseases. C-peptide levels were < 0.8 ng/mL in 17 patients and undetectable in six patients. Two patients experienced diabetic ketoacidosis (DKA). Insulin treatment was required by 18 patients with a mean (+/- SD) dosage of 30 +/- 9 U/day. During follow-up of 14 of the patients for 9.8 +/- 4.3 months, HbA1c decreased significantly. Their mean body weight and body mass index increased significantly from 36.6 +/- 4.6 kg to 47.2 +/- 6.2 kg and 13.9 +/- 0.9 to 18.0 +/- 1.9 kg/m2, respectively. Careful attention should be paid to diabetic control and associated chronic illness in patients with severe undernutrition.

Alteration of cerebral microcirculation by hemodilution with hemosome in awake rats

Our study showed that hemodilution with modified fluid gelatin resulted in an increase in local cerebral blood flow (LCBF), but no change at all in local cerebral oxygen delivery (LCOD) in rats. Hemosome, a lecithin encapsulated hemoglobin having the oxygen-carrying capacity, was developed to improve LCOD by hemodilution. Therefore, we have hypothesized that LCBF & LCOD would be increased by hemodilution with hemosome. To test this hypothesis, adult male Sprague-Dawley rats weighing approximately 350g were used and divided into the hemodilution and the control groups. Hemosome was made from pig red blood cells and lecithin. It's mean diameter was approximately 0.3 um and hemoglobin concentration was approximately 4g/dl. Isovolemic hemodilution, which lowered the systemic hematocrit from approximately 50% to approximately 30%, was achieved by rapidly replacing blood with the same volume of hemosome. Ten min later, LCBF in 14 brain structures were measured using the 14C-iodoantipyrine technique. Our results showed that LCBF of the control group ranged from 115 +/- 11 ml/100g/min in the medulla to 260 +/- 31 ml/100g/min in the occipital cortex. LCBFs were generally higher (p < 0.05, MANOVA) by 16% in the hemodilution group than in the control group. However LCODs were generally decreased (p < 0.05, MANOVA) by 18% in the hemodilution group than in the control. In conclusion, hemodilution with hemosome indeed improves LCBF but lowers LCOD in awake rats.

A reposition of Tennison's triangular flap in long lip deformity

The authors have used a new technique in 5 cases with severe long lip deformity and drooping of the Cupid's bow, who all have undergone Tennison's triangular flap method for unilateral cleft lip at primary repair. We corrected this deformity by repositioning Tennison's triangular flap back into its original site and then obtained (1) effective shortening of a vertical lip length, (2) restoration of a symmetric Cupid's bow, (3) prevention of tight upper lip, (4) refinement of the transverse scar, and (5) low recurrence.

Delayed presentation of cerebral arterial gas embolism following proven intraoperative venous air embolism

We describe the case of a 33-year-old woman who suffered a delayed-onset arterial gas embolism following a significant venous air embolism during surgery to remove an acoustic neuroma. We report the management of the problem and discuss the mechanisms by which this event might have occurred.

Long-term synaptic transformation of hippocampal CA1 gamma-aminobutyric acid synapses and the effect of anandamide

Evidence is presented for a distinctive type of hippocampal synaptic modification [previously described for a molluscan gamma-aminobutyric acid (GABA) synapse after paired pre- and postsynaptic excitation]: transformation of GABA-mediated synaptic inhibition into synaptic excitation. This transformation persists with no further paired stimulation for 60 min or longer and is termed long-term transformation. Long-term transformation is shown to contribute to pairing-induced long-term potentiation but not to long-term potentiation induced by presynaptic stimulation alone. Further support for such mechanistic divergence is provided by pharmacologic effects on long-term transformation as well as these two forms of long-term potentiation by Cl- channel blockers, glutamate and GABA antagonists, as well as the endogenous cannabinoid ligand anandamide.

Efficacy of intravenous delta-aminolaevulinic acid photodynamic therapy on rabbit papillomas

Endogenously induced protoporphyrin IX (PPIX), a metabolite of delta-aminolaevulinic acid (ALA), has been evaluated as a photosensitising agent for destruction of papillomas in cottontail rabbit papillomavirus-infected Dutch belted and New Zealand rabbits. Three factors were evaluated: (1) relative retention ratio of drug in normal tissue, papilloma and plasma over time; (2) tissue tolerance to treatment factors; and (3) efficacy of treatment protocol. Three drug doses of ALA were examined: 50, 100 and 200 mg kg-1. Actual PPIX concentrations in tissue and plasma were determined spectrophotofluorometrically. The optimal treatment time occurred 3-6 h post ALA injection. The highest PPIX concentration ratio between papilloma and normal skin was 6:1. Different light doses were investigated, using an injection to exposure interval of 3 h and an irradiance of 100 mW cm-2 at a wavelength of 630 nm. Efficacy without risk of significant damage to normal skin was obtained using 100-200 mg kg-1 ALA and 40-60 J cm-2. A long-term (3 months) cure rate of 82% was obtained with a single treatment, provided that papilloma depth did not exceed 8 mm, volume was not more than 1000 mm3 and the plasma concentration of PPIX immediately before exposure was above 500 micrograms ml-1. The short time between injection and treatment and high efficacy, together with PPIX disappearance from plasma and tissue within 24 h, make injected ALA a highly attractive drug for photodynamic therapy.

Functional expression of the tachykinin NK1 receptor by floor plate cells in the embryonic rat spinal cord and brainstem

1. The floor plate is a ventral mid-line structure that plays a pivotal role in the organization of the developing vertebrate central nervous system. Previous studies have demonstrated that the floor plate may provide signals that induce neuronal differentiation and guide axons; however, it is not known whether the floor plate can itself respond to signals that derive from surrounding tissue. 2. The peptide substance P is one of the first transmitters to be expressed in the developing spinal cord. To determine whether the floor plate may respond to substance P we have examined the expression of the principal substance P receptor (the tachykinin NK1 receptor) by floor plate cells of the rat embryonic spinal cord using immunocytochemistry, in situ hybridization and fura-2 calcium imaging. 3. Immunocytochemistry demonstrated selective expression of the NK1 receptor by cells at the ventral mid-line of the spinal cord. Double immunofluorescence labelling with the specific floor plate marker FP3 indicated that NK1 receptor expression is confined to cells in the lateral region of the floor plate. 4. In order to confirm the specificity of the NK1 receptor immunoreactivity we performed in situ hybridization histochemistry using antisense cRNA probes directed against the NK1 receptor. In situ hybridization demonstrated selective expression of NK1 receptor mRNA by floor plate cells. 5. The ontogeny of NK1 receptor protein and mRNA expression in the floor plate was defined. NK1 receptor expression occurred in a rostrocaudal progression that begins at embryonic day 10-11 (E10-E11) and is complete by E12-E14. The restriction of NK1 receptor expression to the lateral part of the floor plate was conserved throughout embryonic development. 6. NK1 receptor signalling was assessed by monitoring substance P-evoked changes in the intracellular concentration of calcium ions ([Ca2+]i) of acutely dissociated cells from the floor plate region. Application of substance P (5 nM) elevated [Ca2+]i in 10% of cells examined. 7. Selective neurokinin agonists were used to identify the receptor subtype involved in the substance P-evoked elevation of [Ca2+]i. Acetyl-[Arg6,Sar9,Met(O2)11]-substance P(6-11) (5 nM) and [Sar9,Met(O2)11]-substance P (5 nM), two highly selective NK1 receptor agonists, both elevated [Ca2+]i in floor plate cells that responded to substance P. [beta-Ala8]-neurokinin A(4-10) (50 nM) and senktide (50 nM), selective agonists respectively of NK2 and NK3 receptors, had no effect on [Ca2+]i.