Voltage dependent calcium channels in cerebellar granule cell primary cultures

Voltage activated calcium channels were studied in rat cerebellar granule cells in primary culture. Macroscopic currents, carried by 20mM Ba2+, were measured in the whole-cell configuration. Slowly inactivating macroscopic currents, with a maximum value at a membrane potential around 5 mV, were recorded between the 1st and the 4th day in culture. These currents were completely blocked by 5mM Co2+, partially blocked by 10 microM nifedipine, and increased by 2 to 5 microM BAY K-8644. Two types of channels, in the presence of 80 mM Ba2+, were identified by single channel recording in cell-attached patches. The first type, which was dihydropyridine agonist sensitive, had a conductance of 18 pS, a half activation potential of more than 10 mV and did not inactivate. This type of channel was the only type found during the first four days in culture, although it was also present up to the 11th day. The second type of channel was dihydropyridine insensitive, had a conductance of 10 pS, a half activation potential less than -15 mV, and displayed voltage dependent inactivation. This second type of channel was found in cells for more than four days in culture.

Transfer of silver-stained proteins from polyacrylamide gels to polyvinylidene difluoride membranes

We have developed a method to transfer proteins from a silver-stained polyacrylamide gel to a polyvinylidene difluoride (Immobilon-P) transfer membrane (Millipore, Bedford, MA). If the silver stained gels are rinsed in 2 x SDS Laemmli sample buffer prior to transfer, almost all proteins can be transferred comparably to non-stained controls. Some proteins stained with silver can be directly transfer, almost all proteins can be transferred comparably to non-stained controls. Some proteins stained with silver can be directly transferred to a single sheet of Immobilon-P without a prior rinse in sample buffer. Most important in the Western blot the antigenicity of the transferred protein is retained in either way. The method described is simple, inexpensive and versatile. A slight modification of the technique permits one to extract minor proteins, or detect their antigenic activities, without contamination of contiguous proteins.

Antioxidant action of certain simple phenolic compounds derived from Chinese herbs

H2O2 and hydroxyl free radical active oxygen generation systems were utilized to define the antioxidant activities of simple phenolic compounds derived from Chinese herbs. Although the antioxidant activities of compounds differed when assessed in the two systems, all compounds tested were found to be effective at preventing red blood cell membrane lipid peroxidation, with the propyl and butyl esters of gallic acid being especially potent. No compound was able to prevent hemoglobin oxidation. All compounds but salicylic acid were found to interact dose-dependently with H2O2 and hydroxyl free radical as determined by a chemiluminescence method.

Local recurrence of soft tissue sarcoma following brachytherapy

Twenty-five patients with soft tissue sarcomas were treated with Ir192 implants following wide local excision at our institution between 1982 and 1987. External beam radiotherapy was given in addition to the implant in a majority of patients. The median follow-up in these 25 patients is 36 months (12 to 75 months). Twenty patients have had no evidence of local recurrence following their primary treatment (FFR = 80%). A multivariate analysis using stepwise logistic regression was used to predict failure in 3 years or less. Potential predictors examined included age, sex, tumor location, primary versus recurrent disease, grade, histology, surgical margins, implant only versus implant plus external beam, and a ratio of the volume of tissue which received 65 Gy (TV65) to the tumor volume (TV), that is (TV65/TV). The single variable which was significantly associated with local failure by 3 years was a TV65/TV of less than one. Once this variable was entered into the analysis, no other factor proved statistically significant. Our data suggest that when attempting local control of soft tissue sarcomas with brachytherapy, the volume of tissue receiving 65 Gy (TV65) from both implant and external beam must exceed the volume of the excised lesion (TV). Since the volume of a tumor can be readily determined prior to surgical excision either by CT or MRI scanning, pre-planning of the implant volume could potentially reduce the rate of local failure.

Highly parallel single-mode multiplanar holographic interconnects

We present theoretical and experimental results of a novel highly parallel multiplanar holographic interconnect design. It combines single-mode integrated optics with highly efficient volume holography and holographic waveguide couplers. A multiple-plane optical bus was fabricated. The interconnect density and power budget of the system are presented. This new type of very-large-scale integrated interconnect can provide performance benefits for local area networks and highly parallel supercomputing systems.

Competitive blockage of the sodium channel by intracellular magnesium ions in central mammalian neurones

The aim of this study was to determine from macroscopic current analysis how intracellular magnesium ions, Mgi2+, interfere with sodium channels of mammalian neurones. It is reported here that permeation across the sodium channel is voltage- and concentration-dependently reduced by Mgi2+. This results in a general reduction of sodium membrane conductance and an outward sodium peak current at large positive potentials. 30 mM Mgi2+ leads ot a negative shift of voltage dependence of sodium channel gating parameters, probably due to the surface potential change of the membrane. This shift alone is, however, insufficient to explain the reduction of outward sodium currents. The blockage by Mgi2+ is decreased upon increasing intracellular or extracellular Na+ concentration, which suggests that Mgi2+ interferes with sodium permeation by competitively occupying sodium channels. Using a kinetic model to describe the sodium permeation, the dissociation constant (at zero membrane potential) of Mgi2+ for the sodium channel has been calculated to be 8.65 +/- 1.51 mM, with its binding site located at 0.26 +/- 0.05 electrical distance from the inner membrane. This dissociation constant is smaller than that of Nai+, which is 83.76 +/- 7.60 mM with its binding site located at 0.75 +/- 0.23. The low dissociation constant of Mgi2+ reflects its high affinity for the sodium channel.

Development of voltage-dependent ionic currents in rat cerebellar granule cells grown in primary culture

In this work we studied the excitable properties of cerebellar granule cells grown in primary culture in the presence of "high" KCl (25 mM). Whole cell patch-clamp records of currents were obtained from cells at 1-33 days in culture (DIC). Sodium currents, blocked by TTX, were present from the first DIC and did show slow developmental changes. Two types of potassium currents were detected at all DIC: a delayed rectifier current (IK) and an inactivating current (IA). Both IK and IA increased until 7 to 9 DIC (four and two times respectively). Most of the IA increase, however, correlated with an increase in cell size, monitored by measurements of cell membrane capacitance (Cm) and the current density thus did not change. Conversely, delayed rectifier potassium current density did increase in the initial DIC (3-6) and did not change significantly after this time. Calcium currents were not detectable at any DIC under our experimental conditions.

Characterization of "peak E," a novel amino acid associated with eosinophilia-myalgia syndrome

Epidemiologic studies strongly associate eosinophilia-myalgia syndrome (EMS) with ingestion of tryptophan containing a contaminant ("peak E"). Prior reports have suggested that peak E is the di-tryptophan N alpha-animal of acetaldehyde. Spectral and chemical studies now demonstrate that peak E is 1,1'-ethylidenebis[tryptophan]. This novel amino acid may be the etiological agent responsible for EMS, or it may be a marker of a still unidentified causal agent.

Optically addressed variable-efficiency waveguide grating for switching arrays

An optically addressed waveguide grating switch is described and demonstrated. Its structure includes a planar slab waveguide with a surface relief grating and an active-material cladding layer. Photoinduced birefringence due to a polarized argon laser beam causes modulation of the refractive index of the cladding in the grating region and modulation of diffraction efficiency of the waveguide grating.

Optical polynominal processing based on a cascaded holographic structure

An optical polynomial processor is investigated to evaluate a general class of nonlinear functions. The polynomial processor is based on a cascaded holographic array that is reconstructed by an off-Bragg laser beam. By means of cascaded off-Bragg reconstructions, a series of polynomial terms can be obtained in parallel at light-transmitted speed.

Voltage dependent sodium currents in cultured rat cerebellar granule cells

Sodium currents were studied in granule cells dissociated from rat cerebellum. Macroscopic currents were recorded using the patch-clamp technique. Sodium currents, which are TTX sensitive, reached a maximum peak value of 0.42 +/- 0.08 pA/microns2 at 18.4 +/- 2.2 mV (n = 6). Activation and inactivation kinetics and steady-state properties were described in terms of Hodgkin and Huxley parameters. The properties of sodium channels in cultured rat cerebellar granule cells are very similar to those reported for various neural preparations.

Treatment of functional headache with Chinese herbal inhalant--a report of 496 cases

Headaches of the neurofunctional type, blood vascular type, neuro-vascular type, and musculotonic type are commonly encountered clinically. The authors report a nasal inhalant of Chinese herbal drugs which has been effective in the treatment of these varieties of headache.

Optical multiplanar VLSI interconnects based on multiplexed waveguide holograms

Optical interconnects for very large scale integration systems based on planar waveguide holograms are analyzed. The combination of low loss waveguides and multiplexed waveguide holograms allows the construction of various compact planar architectures with high interconnect density and low insertion loss. The long interaction lengths possible in planar structures result in high angular and wavelength selectivity. Holographic grating couplers and multiplexed planar holograms for 1-to-3 interconnects and 1-to-3 multiple wavelength interconnects were fabricated.

Radiobiological advantages of an immediate interstitial boost dose in conservative treatment of breast cancer

Minimum surgery with irradiation is emerging as one of the main modalities of therapy for operable early breast cancer. Between June 1982 and June 1986, 110 breasts with Tis, T1 to T3 lesions have been treated at our institution with lumpectomy and interstitial irradiation to the tumor bed with Iridium-192 perioperatively followed by external beam irradiation. There have been two local recurrences at or near the vicinity of the primary, at a median follow-up of 60 months. To analyze the parameters that might have contributed to the local control, we have examined the treatment volumes, prescribed dose to the tumor bed, dose at the core of the tumor bed, and dose to the surrounding normal tissue. Immediate interstitial implant has the radiobiological advantage of delivering continuous low dose irradiation, immediately upon removal of gross tumor to residual foci. Implantation of the afterloading catheters intraoperatively facilitates accurate dose delivery and avoidance of geographical misses. By precise treatment of any residual foci, immediately upon removal of the gross mass, perioperative interstitial irradiation improves local control and by facilitating less radical surgical excision, leads to better cosmetic results.

Post traumatic extracranial vertebral artery dissection with locked-in syndrome: a case with MRI documentation and unusually favourable outcome

A patient with a right vertebral artery dissection occurring after minor head trauma progressed to a massive pontine infarction. An unusually favourable outcome and MRI imaging are discussed.