Fiber optic sensor for Ca2+ based on an induced change in the conformation of the protein calmodulin

A fiber optic sensor that exploits the natural selectivity of the Ca(2+)-binding protein calmodulin (CaM) is described. In this sensor, a dialysis membrane is used to entrap a fluorescein-labeled CaM (F-CaM) solution at the common end of a bifurcated fiber optic bundle. Ca2+ ions in a sample solution can diffuse through the membrane and bind to the F-CaM. Upon binding with Ca2+, CaM undergoes a conformational change that induces a change in the fluorescence of the attached fluorescein tag. This change in fluorescence can be related to the concentration of Ca2+ in the sample solution. The detection limit for the sensor is 5 x 10(-8) M Ca2+. The sensor has no interference by Mg2+ at concentrations as high as 10(-2) M.

Effects of cilazapril on cerebral vasodilatation in hypertensive rats

Endothelium-dependent dilatation of cerebral arterioles is impaired during chronic hypertension. The goal of this study was to determine the effects of an angiotensin converting enzyme inhibitor, cilazapril, on endothelium-dependent dilatation in pial arterioles. Four-month-old Wistar-Kyoto (WKY) rats and stroke-prone spontaneously hypertensive rats (SHRSP) received cilazapril in their drinking water (500 mg/L) for 3 to 6 months. Treatment with cilazapril reduced mean arterial pressure in both WKY rats and SHRSP and had no significant effect on baseline diameter of pial arterioles measured with a cranial window. Responses to bradykinin and A23187, but not to nitroglycerin and adenosine, were impaired in SHRSP. Cilazapril did not affect responses to bradykinin (3 x 10(-7) M) and A23187 (10(-5) M) in WKY rats but significantly increased cerebral vasodilatation in response to bradykinin (52 +/- 4% vs 27 +/- 5%) and A23187 (19 +/- 3% vs 8 +/- 3%) in SHRSP. Cilazapril also tended to increase dilator responses to nitroglycerin and adenosine in SHRSP. In another group of SHRSP, treatment with cilazapril for 4 days produced a moderate reduction in blood pressure and increased cerebral vasodilatation in response to bradykinin, A23187, and adenosine. Topical application of the active form of cilazapril (cilazaprilat) for 40 minutes also increased cerebral vasodilatation in response to bradykinin, A23187, and nitroglycerin in SHRSP. The data indicate that an angiotensin converting enzyme inhibitor enhances cerebral vasodilatation in response to endothelium-dependent agonists in SHRSP and may also increase responses to endothelium-independent agonists.

Continuous-wave singly resonant optical parametric oscillator pumped by a single-frequency resonantly doubled Nd:YAG laser

We report what is to our knowledge the first demonstration of a continuous-wave singly resonant optical parametric oscillator based on potassium titanyl phosphate. The pump source used is a single-frequency resonantly doubled Nd:YAG laser. By double passing the pump through the crystal, we achieved a minimum oscillation threshold of 1.4 W. With 3.2 W of incident pump power, a maximum 1.07 W of nonresonant idler power was generated. Spectral measurement reveals that the singly resonant optical parametric oscillator operates consistently in a single axial mode with much relaxed axial mode hop tolerance to cavity length and pump-frequency fluctuations compared with doubly resonant optical parametric oscillators previously demonstrated.

Intracranial fetus-in-fetu: CT diagnosis

The authors present a case of fetus-in-fetu in which the CT findings are compatible with an earlier description by Nocera et al., i.e., a "round or tubular collection of very low density fat surrounding a central bony structure (probably one of the legs)." Additionally, sonography showed a heterogeneous mass with limb-like structures in the left lateral ventricle. Plain films can confirm the presence of a vertebral column and identify specific bony structures, but CT is a valuable aid in cases where plain films were not obtained or are inconclusive.

6.5-W, 532-nm radiation by cw resonant external-cavity second-harmonic generation of an 18-W Nd:YAG laser in LiB(3)O(5)

We report 6.5 W of TEM(00) cw 532-nm radiation generated by external resonant doubling in a LiB(3)O(5) crystal. An 18-W, cw, injection-locked single-frequency Nd:YAG laser was used to generate 532-nm second-harmonic output with a 3-dB heterodyne linewidth of 15 kHz.

Mechanisms of impaired endothelium-dependent cerebral vasodilatation in response to bradykinin in hypertensive rats

Bradykinin produces less dilatation of pial arterioles in stroke-prone spontaneously hypertensive rats than in normotensive Wistar-Kyoto rats. The goals of this study were to determine the mediator of bradykinin-induced dilatation in cerebral arterioles of rats and to determine whether responses to this mediator are altered in hypertensive rats. Diameter of pial arterioles (20-65 microns) was measured using intravital microscopy in 18 normotensive and 17 hypertensive rats. Superfusion of 3 x 10(-7) M bradykinin dilated pial arterioles by 53 +/- 4% (mean +/- SEM) in normotensive rats but only 33 +/- 6% in hypertensive rats (p less than 0.05 versus normotensive rats). Vasodilatation in response to bradykinin was almost completely inhibited by 280 units/ml catalase in both normotensive and hypertensive rats (n = 7 and n = 7, respectively) whereas 150 units/ml superoxide dismutase (n = 6 and n = 5, respectively) and 1 mM deferoxamine (n = 5 and n = 5, respectively) did not attenuate bradykinin-induced vasodilatation. These findings suggest that hydrogen peroxide is the mediator of bradykinin-induced dilatation in cerebral arterioles of rats. We also examined responses of cerebral arterioles to hydrogen peroxide in five normotensive and six hypertensive rats. Dilator responses of cerebral arterioles to 3.2 x 10(-5) M to 1.6 x 10(-4) M hydrogen peroxide did not differ in normotensive and hypertensive rats, which suggests that impaired dilatation of cerebral arterioles in response to bradykinin is not related to altered responsiveness of smooth muscle to an endothelium-derived relaxing factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Endothelium-dependent responses of cerebral blood vessels during chronic hypertension

Acetylcholine produces less dilatation of pial arterioles in stroke-prone spontaneously hypertensive rats (SHRSP) than in normotensive (WKY) rats. Responses of cerebral vessels to acetylcholine and bradykinin appear to involve different mechanisms. Our first goal was to determine whether responses of pial arterioles to bradykinin are impaired in SHRSP. Diameter of pial arterioles (20-60 microns) was measured using intravital microscopy in WKY rats and SHRSP (9-12 months old). Superfusion of bradykinin (3 x 10(-7) M) dilated pial arterioles by 35 +/- 6% (mean +/- SEM) in WKY rats, but only 21 +/- 3% in SHRSP (p less than 0.05 versus WKY rats). Both nitric oxide (5 x 10(-7) M) and nitroglycerin (10(-5) M) produced similar vasodilatation in WKY rats and SHRSP. Our second goal was to determine whether alteration of postreceptor mechanisms contributes to impairment of endothelium-dependent cerebral vasodilatation in SHRSP. Calcium ionophore A23187 (10(-5) M) produced more vasodilatation in WKY rats than in SHRSP (32 +/- 8% versus 9 +/- 4%, p less than 0.05). Responses to A23187 (10(-5) M) were inhibited by indomethacin (46 +/- 13% versus 15 +/- 5%, p less than 0.05) in WKY rats, whereas responses to A23187 (10(-6) M) were potentiated modestly by indomethacin (-3 +/- 2% versus 4 +/- 2%, p less than 0.05) in SHRSP.(ABSTRACT TRUNCATED AT 250 WORDS)

Injection locking of a 13-W cw Nd:YAG ring laser

A lamp-pumped, 13-W cw Nd:YAG ring laser at 1.064 microm is injection locked using a 40-mW single-frequency diodelaser-pumped Nd:YAG laser as the master oscillator. The phase fidelity of the injected slave to the master is measured using an all-optical technique.

Injection locking of a 13-W cw Nd:YAG ring laser

A lamp-pumped, 13-W cw Nd:YAG ring laser at 1.064 microm is injection locked using a 40-mW single-frequency diodelaser-pumped Nd:YAG laser as the master oscillator. The phase fidelity of the injected slave to the master is measured using an all-optical technique.

Liquid chromatographic determination of the pH-dependent degradation of eseroline — hydrolysis product of physostigmine

The stability of eseroline, the hydrolysis product of physostigmine under aerobic conditions, was studied by liquid chromatography. A reversed-phase, ion-pair technique was used to separate eseroline from its degradation products. The degradation of eseroline in phosphate buffer solutions of pH 6.91, 7.40, 7.98, 8.41 and 8.94 appears to follow first-order kinetics; the rate constant increased with an increase in pH. The degradation appears to follow specific base catalysis.

Effects of gentamicin solution and cream on the healing of open wounds

When 0.1% gentamicin solution was applied to full-thickness skin wounds of dogs, the wounds became smaller by contraction during the first 7 days and continued to contract over the next 14 days. Wounds treated with 0.1% gentamicin cream enlarged during the first 7 days, followed by wound contraction over the next 14 days. The wounds treated with gentamicin solution also had more epithelialization at 7 days than did the cream-treated wounds; however, epithelialization of the 2 types of wounds was similar at 14 and at 21 days. Gentamicin solution and cream were effective in controlling bacterial growth on wounds when compared with the bacterial growth on the control wounds (not treated with antibiotics).

Macrophage stimulation by bacterial lipopolysaccharides. II. Evidence for differentiation signals delivered by lipid A and by a protein rich fraction of lipopolysaccharides

Stimulation of macrophages to lyse tumor cells is a property common to lipopolysaccharide (LPS) extracted from a variety of smooth and rough bacterial strains by several different preparative procedures. The relationship between macrophage stimulation and the structural characteristics of LPS is defined. In protein-free LPS, lipid A bears the stimulatory signal which results in the differentiation of elicited macrophages into killer cells. The polysaccharide moiety is neither stimulatory itself nor does it block the activity of complete LPS on macrophages. Extraction of LPS by the butanol or Boivin procedures produces preparations in which LPS is complexed through its lipid A moiety to a protein rich component, LAP. Isolated LAP delivers a macrophage differentiation signal which is independent of lipid A. The presence of these two structurally distinct constituents in the cell walls of gram-negative bacteria broadens the biological environments in which they can stimulate macrophages in vivo.