[The blood-brain barrier: a specialty of cerebral microcirculation systems].
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
S Wolf
Publications and source records attributed to S Wolf.
Polysensory response characteristics of dorsal root ganglion neurones that may serve sensory functions during myocardial ischaemia.
OBJECTIVE: To determine the response characteristics of dorsal root ganglion neurones that may serve sensory functions during myocardial ischaemia. METHODS: Extracellular recordings were made from 54 spontaneously active and 5 normally quiescent dorsal root ganglion neurones (T2-T5) in 22 anaesthetized open-chest dogs under control conditions and during epicardial mechanical or chemical stimulation and myocardial ischaemia. RESULTS: The activity of 78% of spontaneously active and all quiescent neurones with left ventricular sensory fields was modified by left ventricular ischaemia. Forty-six spontaneously active neurones (85%) were polysensory with respect to mechanical and chemical stimuli. The 5 quiescent neurones responded only to chemical stimuli. Spontaneously active neurones associated with left ventricular mechanosensory endings (37 neurones) generated four different activity patterns in response to similar mechanical stimuli (high or low pressure active, high-low pressure active, high-low pressure inactive). A fifth group generated activity which was not related to chamber dynamics. Adenosine, adenosine 5'-triphosphate, substance P and bradykinin modified 72, 61, 65 and 63% of the spontaneously active neurones, respectively. Maximum local mechanical or chemical stimuli enhanced activity to similar degrees, as did ischaemia. Each ischaemia-sensitive neurone displayed unique activity patterns in response to similar mechanical or chemical stimuli. CONCLUSIONS: Most myocardial ischemia-sensitive dorsal root ganglion neurones associated with epicardial neurites sense mechanical and multiple chemical stimuli, a small population sensing only mechanical or chemical stimuli. Activity patterns generated by these neurones depend on their primary sensory characteristics or those of other neurones that may converge on them, as well as the type and magnitude of the stimuli that impinge upon their sensory fields, both normally and during ischaemia.
Adenosine↗
Indocyanine-green angiography in patients with occult choroidal neovascularization.
Several studies have stressed the role of indocyanine-green (ICG) angiography in patients with occult choroidal neovascularization (O-CNV) secondary to age-related maculopathy (ARM). The present study was undertaken to evaluate the percentage of eyes that could be converted from O-CNV without suffering pigment epithelial detachment (PED) in well-defined CNV using ICG angiography with a scanning laser system. A total of 112 patients with ARM and O-CNV without PED were included in this prospective study. All patients underwent ICG angiography with a scanning laser system. The early phase (first 3 min) of the ICG angiogram was analyzed for the presence of a neovascular network, whereas focal or irregular hyperfluorescence was noted in the late phase. The early phase of the ICG angiograms revealed in 62 (55%) eyes a well-defined CNV. In 55 of these eyes, late irregular hyperfluorescent and hypofluorescent zones were observed. Another 27 eyes presented with focal hyperfluorescent areas in the latephase studies without having shown a well-demarcated area of neovascularization in the early phase of the ICG angiogram. This study confirms that ICG angiography is an important adjunctive method to fluorescein angiography. In more than 50% of eyes with O-CNV the ICG angiograms obtained with a scanning laser ophthalmoscope enable the visualization of a neovascular network in the early phase.
Aged↗
Randomized controlled trial of ACE-inhibitors and beta-blockers with and without vasodilating activity in chronic glomerulonephritis.
A prospective double-blind, randomized study was conducted to compare the effects of the beta 1 antagonist, beta 2 agonist celiprolol (200 mg daily) on renal hemodynamics and protein excretion with those of the beta 1 antagonist atenolol (50 mg daily), the ACE-inhibitor ramipril (2.5 mg daily), and placebo in 11 patients with proteinuria > 400 mg/24 h due to chronic glomerulonephritis. All 4 substances were given in a double-blind, randomized manner according to a latin-square design over a period of 4 weeks with a wash-out period of 2 weeks in between. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured by inulin and PAH clearance. Proteinuria was assessed by urine sampling at the end of each treatment period. Mean arterial pressure (MAP) was reduced significantly (p < 0.01) by all 3 drugs compared to placebo (108 +/- 9 mmHg placebo, 98 +/- 12 mmHg atenolol, 101 +/- 11 mmHg celiprolol, and 98 +/- 8 mmHg ramipril). Celiprolol induced a significant increase in ERPF compared to placebo (322 +/- 109 ml/min under placebo versus 391 +/- 110 ml/min under celiprolol, p < 0.05). GFR was slightly but insignificantly increased under atenolol and celiprolol. Filtration fraction (FF) remained unchanged in case of atenolol and celiprolol treatment and was slightly but not significantly reduced by ramipril. Proteinuria was significantly (p < 0.05) reduced compared to placebo by all 3 drugs (1.8 +/- 1.3 g/24 h under placebo, 1.2 +/- 1.2 g/24 h under atenolol, 1.2 +/- 1.1 g/24 h under celiprolol, and 1.4 +/- 1.4 g/24 h under ramipril). These data demonstrate that new beta-blocking agents show favorable effects on proteinuria and renal blood flow in patients with chronic glomerulonephritis and arterial hypertension. This may be attributed to their vasodilating properties.
Adrenergic beta-1 Receptor Antagonists↗
Subpressor doses of angiotensin II do not increase albumin excretion in humans.
The objective of our study was to evaluate the effects of subpressor doses of angiotensin II and mild physical stress on renal hemodynamics and urinary albumin excretion (UAE) in a group of young patients with essential hypertension compared to normotensive subjects. Eleven patients (26 +/- 6 years) and ten healthy control persons (25 +/- 2 years) were enrolled in the study. Secondary forms of hypertension had been excluded. Angiotensin II was infused at a dose of 0.3 and 1.0 ng/kg/min and physical stress testing was done with a cycle ergometer (50 W at 10 min for hypertensives, 100 W at 10 min for normotensives). Renal hemodynamics were assessed by clearance techniques (continuous insulin and p-aminohippurate clearance). Mean arterial pressure (MAP) and UAE were significantly higher in the hypertensive group than in normotensive control persons at any time of measurement. There was no significant increase in MAP or UAE under angiotensin II infusion either in the hypertensive group or in the normotensive group. MAP increased significantly under physical stress in the normotensive group only (83 +/- 7 mmHg baseline vs. 108 +/- mmHg during physical stress, p < 0.05). Angiotensin II infusion resulted in a significant change concerning renal hemodynamics in the hypertensive group only. The filtration fraction increased (18 +/- 3% baseline vs. 25 +/- 7% under infusion of 1.0 ng/kg/min angiotensin II, p < 0.05) due to a decline in ERPF and an increase in GFR in the hypertensive group. The amount of UAE correlated with the magnitude of the MAP in both groups. No correlation was found between renal hemodynamic parameters and the UAE. A significant correlation was found between the norepinephrine levels and the UAE in the control group. We could not demonstrate an albuminuric effect of subpressor doses of angiotensin II in normotensive or hypertensive subjects despite its well known effects on renal hemodynamics with an increase of the filtration fraction. These data provide evidence against a predominant role of angiotensin II and renal hemodynamics concerning the elevated urinary albumin excretion in young patients with arterial hypertension.
Adult↗
"Sniffin' sticks": screening of olfactory performance.
"Sniffin' Sticks" is a new test of nasal chemosensory performance based on pen-like odour-dispensing devices. This portable test is suited for repetitive, inexpensive screening of odour identification. The test includes a forced odour-identification task for seven odours performed by means of a list of four items (multiple-choice). In 146 subjects the basic screening test was compared to a down-scaled version of the UPSIT (CC-SIT). Sniffin' Sticks exhibited a relatively higher coefficient of correlation with the subjects' age; they also demonstrated the women's superior olfactory sensitivity more pronounced when compared to men. In addition, the coefficient of correlation between age and olfactory performance was slightly higher when the sticks were used. Preliminary investigations in nine patients with impaired olfactory function (i.e., anosmic or hyposmic patients) revealed significantly lower scores in patients compared to healthy controls matched for age and sex (p < 0.001). It is concluded that Sniffin' Sticks may be useful in the routine clinical assessment of olfactory performance where both time and costs matter.
Adult↗
Interleukin 12 in combination with anti-interleukin 10 reverses graft prolongation after portal venous immunization.
Portal venous pretransplantation transfusion augments allogeneic skin graft survival in mice transplanted across multiple minor histocompatibility barriers. We have shown in earlier studies that this is correlated with preferential activation for production of type-2 cytokines (interleukin [IL]-4 and IL-10) and decreased production of type-1 cytokines (IL-2 and interferon-gamma). We show that recombinant IL-12, in association with anti-IL-10 monoclonal antibody, can reverse in vivo the graft prolongation afforded by portal venous immunization and the altered cytokine production that follows. These alterations are in turn associated with increased expression of messenger RNA for interferon-gamma, IL-2, and IL-12 and decreased expression of IL-4, IL-10, and IL-13, as determined by non-quantitative polymerase chain reaction using cells obtained from lymph nodes draining the graft. Recombinant IL-12 in vitro also produces dose-related inhibition of activation for production of type-2 cytokines.
Animals↗
IL-12 increases resistance of BALB/c mice to Mycobacterium tuberculosis infection.
IL-12, a cytokine produced by macrophages and B cells, has recently been found to exert pleiotropic effects on the immune system. When BALB/c mice, a strain highly susceptible to virulent Mycobacterium tuberculosis infection, were given IL-12 at the initiation of infection with M. tuberculosis, their mean survival time doubled from 58 to 112 days. IL-12-treated mice had diminished bacterial burdens, whereas treatment with exogenous IFN-gamma had no effect on survival or bacterial burden. IL-12 treatment also delayed lung pathology in BALB/c mice. In contrast with the findings in the BALB/c model, IL-12 did not increase survival of M. tuberculosis-infected gko mice, transgenic mice in which the IFN-gamma gene has been disrupted, indicating that IL-12 does not induce protection against tuberculosis in mice in the absence of IFN-gamma.
Animals↗
Spectroscopy of size-selected neutral clusters: Femtosecond evolution of neutral silver trimers.
Explore the source record for details and available documents.
Journal Article↗
Stability increase of the lumbar spine with different muscle groups. A biomechanical in vitro study.
STUDY DESIGN: This study investigated the influence of five different muscle groups on the monosegmental motion (L4-L5) during pure flexion/extension, lateral bending, and axial rotation moments. OBJECTIVES: The results showed and compared the effect of different muscle groups acting in different directions on the stability of a single motion segment to find loading conditions for in vitro experiments that simulate more physiologically reasonable loads. SUMMARY OF BACKGROUND DATA: In spine biomechanics research, most in vitro experiments have been carried out without applying muscle forces, even though these forces stabilize the spinal column in vivo. METHODS: Seven human lumbosacral spines were tested in a spine tester that allows simulation of up to five symmetrical muscle forces. Changing pure flexion/extension, lateral bending, and axial rotation moments up to +/- 3.75 Nm were applied without muscle forces, with different muscle groups and combinations. The three-dimensional monosegmental motion was determined using an instrumented spatial linkage system. RESULTS: Simulated muscle forces were found to strongly influence load-deformation characteristics. Muscle action generally decreased the range of motion and the neutral zone of the motion segments. This was most evident for flexion and extension. After five pairs of symmetrical, constant muscle forces were applied (80 N per pair), the range of motion decreased about 93% in flexion and 85% in extension. The total neutral zone for flexion and extension was decreased by 83% muscle action. The multifidus muscle group had the strongest influence. CONCLUSION: This experiment showed the importance of including at least some of the most important muscle groups in in vitro experiments on lumbar spine specimens.
Adult↗
The relationship of macular microcirculation to visual acuity in diabetic patients.
OBJECTIVE: To assess the perifoveal microcirculation in diabetic maculopathy without clinically significant macular edema and its relationship to visual acuity. DESIGN: Prospective analysis. SETTING: A teaching hospital. PATIENTS: Fifteen patients with impaired visual acuity of 20/50 or worse, a diabetic control population with unaffected visual acuity (matched age, gender, retinopathy stage), and 52 healthy controls were enrolled. INTERVENTIONS: Study consisted of video-fluorescein angiography with image analyses and hemoglobin A1c measurements. MAIN OUTCOME MEASURES: Macular capillary blood velocity, capillary density (perifoveal intercapillary area), and foveal avascular zone. RESULTS: The capillary blood velocity was significantly reduced in both diabetic groups (P < .001) when compared with healthy controls, but did not differ significantly among the two diabetic groups. The perifoveal intercapillary area and foveal avascular zone were significantly enlarged in both diabetic groups compared with healthy controls (P < .001). The foveal avascular zone (P < .01) and perifoveal intercapillary area (P = .01) were further enlarged in the diabetics with reduced visual acuity. The visual acuity correlated significantly with foveal avascular zone (R2 = .51) and perifoveal intercapillary area (R2 = .24), indicating an association between enlargement and declined visual acuity. CONCLUSIONS: Capillary blood velocity remained unchanged regardless of presence of visual impairment, whereas foveal avascular zone and perifoveal intercapillary area indicated ischemia. This may help in defining a critical hypoxic threshold for visual loss and identifying the presence of an ischemic diabetic maculopathy.
Adult↗
Platelet aggregation inhibiting and anticoagulant effects of oligoamines, XXX: Absorption, organ distribution, and excretion of the oligoamine (+)-(S,S)-1,4-bis-[4-(3-iodo-4-methoxyphenyl)-butylamino]-butane-2,3-di ol and its metabolites.
The pharmacokinetic behaviour of the 131-iodine-labelled title compound 3* and its metabolites in mice was investigated. A two phase, 1st order elimination profile was observed. The second phase is very slow leaving about 35% of radioactivity in the mice even 100 h after i.v. injection, because of high affinity to liver and spleen, caused by strong binding of oligoamines to phospholipids of liver and blood cell membranes. The blood-brain-barrier is not passed. No deep compartments were observed. The doses necessary for antithrombotic effects in vivo were calculated from the blood levels to be 20.5-39.7 mumol/kg for a time interval of 1-6 h after administration.
Animals↗
Distribution behaviour of 131-iodine labelled trans-N,N'-bis-(ethoxy-carbonyl)-N-[4-(3-iodo-4-methoxyphenyl)butyl]-N' -5- phenylpentyl)-1,4-cyclohexanedimethanamine.
The title compound 9, which is a prodrug, and its active metabolite 7 were labelled with 131I (7*/9*) to investigate their pharmacokinetic behaviour, including the distribution between stomach, gut, muscle, blood, lung, liver, kidney, adrenal gland, heart, and spleen. Four hours after oral administration of 7* to mice only 3% of the dose had been absorbed from the g.i. tract. After 24 h 54% of the radioactivity still is found the gut, predominantly in the small intestine. These results explain why 7, which is a potent antiplatelet drug in vitro, shows no antithrombotic effect in vivo. In contrast, the produg 9/9* is absorbed considerably, i.e. up to 50% in 4 h from the g.i. tract depending on the dose applied and the vehicle used. At doses in the micromolar range the absorption appears to be diffusion limited. The highest concentrations are found in the liver and the kidneys suggesting a first pass effect of 7 followed by renal excretion. From the blood levels achieved, the dose necessary for an antithrombotic effect has been calculated to be about 100 mg/kg. In summary, the N-ethoxycarbonyl derivatives of oligoamines appear to be suitable prodrugs for oral administration of oligoamines.
Animals↗
Influence of sodium fluorescein on erythrocyte aggregation in patients with cerebral microangiopathy.
Explore the source record for details and available documents.
Aged↗
Immunoglobulin isotype modulation after administration of IL-12.
We have begun a series of experiments assessing the role of IL-12 in the humoral immune response. IL-12 is known to enhance cellular immunity causing a shift toward a Th1, as opposed to a Th2, response. IL-12 is also a potent stimulator of IFN-gamma production which, among other activities, modulates isotype expression particularly with respect to IgG2a. We have performed a series of experiments involving the concurrent dosing of mice with murine IL-12 and TNP-KLH followed by the monitoring of IgG1 and IgG2a anti-TNP responses and total IgG1 and IgG2a levels. Following administration of IL-12, specific anti-TNP titers showed an IgG2a increase while IgG1 responses were markedly lower than those exhibited by animals which did not receive IL-12. Total IgG1 levels in IL-12 treated mice remained at or near baseline while untreated mice demonstrated an increase in total IgG1 levels. In addition, lymph nodes from these mice were removed, stimulated with KLH and assayed for expression of murine IFN-gamma and IL-4. Murine IFN-gamma levels in supernatants obtained from IL-12 treated mice were elevated over those seen in untreated mice while IL-4 levels were suppressed.
Adjuvants, Immunologic↗
Macular capillary particle velocities: a blue field and scanning laser comparison.
BACKGROUND: Two different techniques are available for measurement of macular capillary particle velocities. The psychophysical blue field simulation technique gives data on macular leukocyte flow velocities, while the scanning laser technique provides information on capillary blood velocities of hypofluorescent segments in the macular network. Published velocity data differ considerably between the two methods. The current study was undertaken to compare the two measuring techniques in a group of healthy volunteers. METHODS: Thirty-two healthy subjects (12 man, 20 women, mean age 27 years) participated in this study. All subjects underwent entoptic leukocyte visualization by means of blue field simulation followed by fluorescein angiography using scanning laser ophthalmoscopy. RESULTS: The capillary blood velocities measured using the scanning laser technique were significantly higher (P < 0.01) than the flow velocities estimated with the blue field simulation technique (2.68 +/- 0.3 mm/s vs 0.89 +/- 0.2 mm/s). No significant correlation between the flow velocities was found (r = -0.22). CONCLUSION: The differences may be related to different measuring locations and/or measurements of different phenomena. The blue field technique estimates average leukocyte flow in the macular network, whereas the scanning laser technique quantifies the velocity of erythrocyte aggregates in the capillary lumen of the para- and perifoveal network. A combination of both techniques may be helpful in interpreting physiological responsiveness and altered velocity pattern in diseased eyes.
Adult↗
Inverted U-pouch ileal reservoir: a technique for conversion of straight ileoanal pull-through.
Explore the source record for details and available documents.
Adult↗
[Acute bilateral amaurosis in sphenoid empyema caused by Streptococcus pneumoniae].
PATIENT: A 14-year-old boy suffered from an acute bilateral blindness which occurred in 24-h time, accompanied by headache and raised temperature, with inconspicuous optic nerve head and fundus. After diagnosis of empyema with magnet resonance tomography (MRT) the sphenoid sinus was fenestrated and streptococcus pneumoniae isolated. Liquor and serology being inconspicuous, there was no evidence of leucaemic or autoimmune disease, intoxication or intracranial tumor. CLINICAL COURSE: The condition of the patient improved under systemic antibiotic therapy. The bilateral amaurosis remained and opticus atrophy developed. CONCLUSION: A bilateral amaurosis with descending opticus atrophy as a consequence of a sphenoiditis and spreading inflammation to the meninges and the optic nerve in the area of the chiasm is a rare event. The imaging technique of the MRT offers new opportunities for an early and more pointed diagnosis and therapy.
Adolescent↗