ERES (ER exit sites) and the "secretory unit concept".

The higher plant Golgi apparatus consists of hundreds of individual Golgi stacks which move along the cortical ER, propelled by the actomysin system. Anterograde and retrograde transport between the endoplasmic reticulum (ER) and the plant Golgi occurs over a narrow interface (around 500 nm) and is generally considered to be mediated by COP-coated vesicles. Previously, ER exit sites (ERES) have been identified on the basis of to localization of transiently expressed COPII-coat proteins. As a consequence it has been held that ERES in higher plants are intimately associated with Golgi stacks, and that both move together as an integrated structure: the "secretory unit". Using a new COPII marker, as well as YFP-SEC24 (a bona fide COPII coat protein), we have made observations on tobacco leaf epidermis at high resolution in the CLSM. Our data clearly shows that COPII fluorescence is associated with the Golgi stacks rather than the surface of the ER and probably represents the temporary accumulation of COPII vesicles in the Golgi matrix prior to fusion with the cis-Golgi cisternae. We have calculated the numbers of COPII vesicles which would be required to provide a typical Golgi-associated COPII-fluorescent signal as being much less than 20. We have discussed the consequences of this and question the continued usage of the term "secretory unit".

Role of cytokinin and auxin in shaping root architecture: regulating vascular differentiation, lateral root initiation, root apical dominance and root gravitropism.

BACKGROUND AND AIMS: Development and architecture of plant roots are regulated by phytohormones. Cytokinin (CK), synthesized in the root cap, promotes cytokinesis, vascular cambium sensitivity, vascular differentiation and root apical dominance. Auxin (indole-3-acetic acid, IAA), produced in young shoot organs, promotes root development and induces vascular differentiation. Both IAA and CK regulate root gravitropism. The aims of this study were to analyse the hormonal mechanisms that induce the root's primary vascular system, explain how differentiating-protoxylem vessels promote lateral root initiation, propose the concept of CK-dependent root apical dominance, and visualize the CK and IAA regulation of root gravitropiosm. KEY ISSUES: The hormonal analysis and proposed mechanisms yield new insights and extend previous concepts: how the radial pattern of the root protoxylem vs. protophloem strands is induced by alternating polar streams of high IAA vs. low IAA concentrations, respectively; how differentiating-protoxylem vessel elements stimulate lateral root initiation by auxin-ethylene-auxin signalling; and how root apical dominance is regulated by the root-cap-synthesized CK, which gives priority to the primary root in competition with its own lateral roots. CONCLUSIONS: CK and IAA are key hormones that regulate root development, its vascular differentiation and root gravitropism; these two hormones, together with ethylene, regulate lateral root initiation.

Immunolocalization of plasma-membrane H+-ATPase and tonoplast-type pyrophosphatase in the plasma membrane of the sieve element-companion cell complex in the stem of Ricinus communis L.

Plasma-membrane-located primary pumps were investigated in the sieve element (SE)-companion cell complex in the transport phloem of 2-week-old stems of Ricinus communis L. and, for comparison, in stems of Cucurbita pepo L. and in the secondary phloem of Agrobacterium tumefaciens-induced crown galls as a typical sink tissue. The plasma-membrane (PM) H+-ATPase and the tonoplast-type pyrophosphatase (PPase) were immunolocalized by epifluorescence and confocal laser scanning microscopy (CLSM) upon single or double labeling with specific monoclonal and polyclonal antibodies. Quantitative fluorescence evaluation by CLSM revealed both pumps in one membrane, the sieve-element PM. Different PM H+-ATPase antibody clones, raised against the PM H+-ATPase of Zea mays coleoptiles, induced in mouse and produced in mouse hybridoma cells, discriminated between different phloem cell types. Clones 30D5C4 and 44B8A1 labeled sieve elements and clone 46E5B11D5 labeled companion cells, indicating the existence of different phloem PM H+-ATPase isoforms. The results are discussed in terms of energization of SE transporters for retrieval of leaking sucrose, K+ and amino acids, as one of the unknown roles of ATP found in SEs. The function of the PPase could be related to phloem sucrose metabolism in support of ATP-requiring processes.

Visual field defect and perfusion of the juxtapapillary retina and the neuroretinal rim area in primary open-angle glaucoma.

BACKGROUND: At this time little information is available about the relationship between glaucomatous visual field defects and impaired blood flow in the optic nerve head. The purpose of this study was to examine blood flow of the juxtapapillary retina and the rim area of the optic nerve head in primary open-angle glaucoma with a borderline visual defect. METHODS: Juxtapapillary retinal and neuroretinal rim area blood flow was measured by scanning laser Doppler flowmetry (SLDF). The visual field was evaluated by static perimetry (Octopus-G1). The optic nerve head was assessed on 15 degrees color stereo photographs. We examined 116 eyes of 91 patients with POAG with controlled IOP and 66 eyes of 44 healthy individuals. The POAG group was divided into eyes with a mean defect lower than 2 dB (POAG group I) and in eyes with a mean defect equal to or greater than 2 dB (POAG group II). The mean age of POAG group I and POAG group II was 55 +/- 11 years and 57 +/- 10 years, respectively. The mean age of the control group was 45 +/- 15 years. The eyes of POAG group I had an average C/D ratio of 0.71 +/- 0.18 with an average mean defect of the visual field of 0.97 +/- 0.68 dB; the eyes of POAG group II had an average C/D ratio of 0.80 +/- 0.17 with an average mean defect of the visual field of 8.2 +/- 6.0 dB. The intraocular pressure on the day of measurement in POAG group I was 18.2 +/- 3.7 mmHg, in POAG group II 17.6 +/- 4.0 mmHg, and in the control group 15.1 +/- 2.5 mmHg. For statistical analysis, age-matched groups of 32 normal eyes of 32 subjects (mean age 52 +/- 10 years) were compared to 18 glaucomatous eyes of 18 patients (POAG group I, mean age 55 +/- 11 years) and 59 glaucomatous eyes of 59 patients (POAG group II, mean age 55 +/- 10 years). RESULTS: In the eyes of POAG group I and POAG group II, both juxtapapillary retinal blood flow and neuroretinal rim area blood flow were significantly decreased compared to an age-matched control group: neuroretinal rim area "flow" POAG group I -65%, POAG group II -66%; juxtapapillary retina "flow" POAG group I -52%, POAG group II -44%. All eyes of the POAG group I (MD < 2 dB) and 56 of 61 eyes of the POAG group II (MD > = 2 dB) showed a retinal perfusion lower than the 90% percentile of normal blood flow. We found no correlation between reduction of juxtapapillary or papillary blood flow and mean defect in POAG eyes. CONCLUSION: Glaucomatous eyes with no defects or borderline visual field defects as well as glaucomatous eyes in an advanced disease stage show significantly decreased optic nerve head and juxtapapillary retinal capillary blood flow.

Effect of breathing 100% oxygen on retinal and optic nerve head capillary blood flow in smokers and non-smokers.

AIM: The effect of breathing 100% oxygen on retinal and optic nerve head capillary blood flow in smokers and non-smokers was investigated using scanning laser Doppler flowmetry (SLDF) as a new non-invasive method to visualise and quantify ocular blood flow. METHOD: 10 eyes of 10 young healthy non-smoking volunteers (mean age 26 (SD 3) years) and nine eyes of nine young healthy smoking volunteers (mean age 26 (4) years) were investigated. All participants were asked not to smoke or consume caffeine containing drinks for at least 4 hours before the measurements. Blood flow measurements were performed before and after 100% oxygen was applied to the subjects through a mask over a period of 5 minutes (6 litres per minute). Juxtapapillary retinal and optic nerve head blood flow were determined in arbitrary units using SLDF representing a combination of laser Doppler flowmetry and a scanning laser system allowing visualisation and quantification of the retinal and optic nerve head blood flow. Blood flow was determined in an area of 100 microns x 100 microns. The level of carboxyhaemoglobin was determined in all subjects. A Wilcoxon matched pairs signed ranks test (non-parametric) was used for statistical evaluation. RESULTS: In the non-smoking group, retinal 'flow' was reduced by 33% (p = 0.005), optic nerve head 'flow' by 37% (p = 0.005). In the smoking group retinal flow was reduced by 10% (p = 0.01), optic nerve head flow by 13% (p < 0.008). The difference in reactivity to oxygen breathing between smokers and non-smokers was highly significant (p < 0.00001). Increased carboxyhaemoglobin levels were not found in either of the groups. A significant reduction of the mean arterial blood pressure of 6% (5%) (p < 0.02) was observed in the non-smoking group after administration of oxygen. CONCLUSION: These results indicate that hyperoxia leads to a decrease in capillary blood flow of the retina and optic nerve head secondary to vasoconstriction, and that smokers do not respond to oxygen breathing as non-smokers do. The findings might be based on factors such as long term effects of nicotine on the sympathetic and parasympathetic nervous system.

[Unnecessary admission from the surgical social medicine viewpoint]. / Fehlbelegung aus chirurgisch-sozialmedizinischer Sicht.

Wrongfully inpatient admission means unnecessary treatment of patients with the means of a hospital. In a study of the Medical Service (MDK) in the German state of Hessen 58% of 954 inpatients were considered wrongfully admitted. 199 patients were treated surgically, the wrongful admission rate of 63% is caused by an unnecessary duration of pre- and postoperative treatment time as well as by organizational deficits.

Perfusion of the juxtapapillary retina and optic nerve head in acute ocular hypertension.

Chronically elevated intraocular pressure (IOP) is often associated with glaucomatous optic nerve atrophy. Impaired blood flow may play a role in the pathogenesis of this disease. We present data concerning juxtapapillary retinal and optic nerve-head blood flow during acute increases in IOP. With the combination of a laser Doppler flowmeter and a scanning-laser system (Scanning Laser Doppler Flowmeter, SLDF; Heidelberg Engineering) the perfusion of the retina and the optic nerve head was quantified and visualized. Juxtapapillary retinal and optic nerve-head blood flow was measured simultaneously by SLDF during variations in IOP induced by a suction cup in nine healthy volunteers. The ocular pressure was increased for 2 min to IOP +15 mmHg, then to IOP +30 mmHg, and finally, to IOP +45 mmHg. Ocular perfusion pressure (PP) was calculated as the mean arterial blood pressure minus the IOP. The declines in juxtapapillary retinal flow as expressed in present per 10-mmHg IOP elevation ranged from 3.6% to 14.1% (median 7.4%). Over all measurements we found a significant linear relationship between juxtapapillary retinal blood flow and PP (r = 0.55, P < 0.0001). The observed decrease in optic nerve-head blood flow with increasing IOP was significantly greater as compared with the retinal blood flow decrease (8.4%/10 mmHg versus 7.4%/10 mmHg, P < 0.05). SLDF enables the quantification and visualization of perfused capillaries of the retina and the optic nerve head in high resolution. Acute elevations of IOP led to a decreases in juxtapapillary retinal and optic nerve-head blood flow of 7.4% and 8.4%/ 10-mmHg IOP increase, respectively.

Perfusion of the juxtapapillary retina and the neuroretinal rim area in primary open angle glaucoma.

PURPOSE: The objective of this study is to evaluate capillary blood flow of the juxtapapillary retina and neuroretinal rim area in primary open angle glaucoma (POAG) by a new noninvasive method performing a high-definition topography of perfused vessels of the retina and the optic nerve head with simultaneous evaluation of blood flow. METHODS: Juxtapapillary retinal and neuroretinal rim area blood flow were measured by scanning laser Doppler flowmetry (SLDF). This new technique is a combination of a laser Doppler flowmeter with a scanning laser system by which the retinal perfusion is simultaneously quantified in 16,000 sites of a retinal area of 2.7 x 0.7 mm. In study I, retinal and optic nerve head blood flow were evaluated by SLDF in 43 patients with POAG and 43 healthy individuals. The mean age of the POAG group was 56 +/- 12 years and of the control group 42 +/- 15 years. In study II, age-matched normals (n = 21) were compared with glaucoma eyes with topical therapy (n = 30) and with glaucoma eyes without topical therapy (n = 16). RESULTS: In study I, the eyes with POAG had an average cup/disc ratio (C/D) of 0.75 +/- 0.20, with an average mean defect of the visual field of 5.3 +/- 5.4 dB. The actual intraocular pressure was 17.8 +/- 4.18 mm Hg in the POAG group and 15.45 +/- 1.82 mm Hg in the control group. For statistical analysis, two age-matched groups of 28 normal eyes of 28 persons with 27 glaucomatous eyes of 27 patients were compared. In normals the blood flow of the neuroretinal rim area was significantly higher than that of the juxtapapillary retinal area (+7.73%, p < 0.01). In POAG both juxtapapillary retinal blood flow and neuroretinal rim area blood flow were significantly decreased compared to an age-matched control group: neuroretinal rim area flow -71% and juxtapapillary retina flow -49%. The decrease of neuroretinal rim area blood flow did significantly correlate with C/D. We found no correlation between reduction of juxtapapillary retinal blood flow and C/D or mean defect. Both glaucoma eyes with and glaucoma eyes without topical therapy showed significant decreased juxtapapillary blood flow compared to normals. We found no significant difference in the juxtapapillary blood flow between glaucoma eyes with and without topical therapy. CONCLUSIONS: In POAG, optic nerve head blood flow and juxtapapillary blood flow were significantly decreased.

Principle, validity, and reliability of scanning laser Doppler flowmetry.

PURPOSE: The objective of this study is to present the reliability and validity of scanning laser Doppler flowmetry (SLDF) performing a high-definition topography of perfused vessels of the retina and the optic nerve head with simultaneous evaluation of blood flow. METHODS: The examination of blood flow by SLDF is based on the optical Doppler effect. The data acquisition and evaluation system is a modified laser scanning device; the wavelength of the laser source is 670 mm, with a power of 100 microW (Heidelberg Engineering, HRF). The reliability of SLDF was estimated by performing five separate measurements in 10 eyes on 5 days. The validity of the method was tested by two experiments. First, in an experimental set-up, the capability of SLDF to measure the velocity of a moving plane in absolute units was estimated. Second, comparative measurements were performed of retinal blood flow in normal eyes and in 33 glaucomatous eyes with SLDF and a commercially available single-point laser Doppler flowmeter (Oculix). RESULTS: We found SLDF to produce a high reliability. The reliability coefficients r1 of flow, volume, and velocity were 0.82, 0.81, and 0.83, respectively. Comparative measurements of the retinal blood flow by SLDF and a single-point laser Doppler flowmeter of corresponding retinal points showed a linear and significant relationship between flow (r = 0.83, p < 0.0001), volume (r = 0.51, p < 0.0001), and velocity (r = 0.59, p < 0.0001). In the experimental set-up, SLDF was able to quantitatively measure velocity in absolute units. CONCLUSIONS: SLDF enables the visualization of perfused vessels of the juxtapapillary retina and the optic nerve head in high resolution by two-dimensional mapping of the optical Doppler shift and a reproducible evaluation of capillary blood flow.

Influence of age on retinal and optic nerve head blood circulation.

PURPOSE: To quantify the influence of age on the retinal perfusion, the authors investigated the microcirculation of the retina and optic nerve head (ONH) and the blood flow velocity in the central retinal artery (CRA). METHOD: The authors examined two groups of healthy volunteers. In group 1 (n=36 eyes of 36 subjects; mean age, 41.5 +/- 14.9 years), retinal and ONH microcirculation was analyzed by scanning laser Doppler flowmetry. In group 2 (n=49 eyes from 49 subjects; mean age, 44.4 +/- 15.4 years), CRA blood flow velocity was examined using pulsed Doppler sonography. RESULTS: Blood flow velocity of the CRA showed a negative correlation to age (systolic velocity, r= -0.47, P=0.001; diastolic velocity r= -0.49, P=0.001). The slope of the linear regression was -0.62 cm/second per 10 years for systolic blood velocity and -0.51 cm/second for diastolic blood velocity. Resistivity index (RI) (RI=[systolic velocity--diastolic velocity]/systolic velocity) as a marker of the rigidity of the vessel increased significantly with age (r=0.40, P=0.004). The slope was 0.03 per 10 years. Retinal microcirculation (flow omega-ret) decreased significantly with age (r= -0.63, P=0.00001). The slope was -34.9[AU] per 10 years. Optic nerve head blood flow showed no significant correlation to age (r= -0.30, P=0.071). CONCLUSION: The authors' data indicate that there is a significant decrease of retinal and CRA blood flow of approximately 6% to 11% per decade. Optic nerve head blood flow seems not to be influenced by age.

Clinical investigation of the combination of a scanning laser ophthalmoscope and laser Doppler flowmeter.

In this report we present the clinical applications of a new noninvasive method of imaging in high definition the topography of perfused retinal vessels. By the combination of a laser Doppler Flowmeter with a scanning laser system the retinal circulation can be visualized and quantified. The principles of measuring blood flow by laser Doppler flowmetry are based on the laser Doppler effect: laser light scattered by a moving particle is shifted in frequency. The scanning laser system is a modified laser scanning tomograph (technical data: retinal area of measurement, 2.7 x 0.7 mm; 10 degrees field with 256 points x 64 lines; horizontal digital resolution, 10 microns; wave-length, 670 nm; light power, 100 micro W; data acquisition time, 2.048 s). Every line is scanned 128-times at a line-sampling rate of 4000 Hz. By the performance of discrete fast fourier transformation over 128 intensities of each retinal point the laser Doppler shift is calculated for each retinal point. With these data a 2-dimensional map of the retinal perfusion with 256 x 64-points is created. The brightness of the picture point is coded by the value of the Doppler shift. By this method we examined health eyes with normal intraocular pressure (IOP) and artificially increased IOP and eyes with glaucomatous optic nerve atrophy, proliferative diabetic retinopathy with areas of capillary occlusion, arterial hypertension with microinfarction of the retina, and central retinal artery occlusion. The application of "scanning laser Doppler flowmetry" (SLDF) leads to the visualization of perfused vessels and capillaries of the retina in high resolution. The examination of perfused retinal arterioles, veins, and capillaries by this method represents the anatomical situation. In SLDF the area of normal or impaired retinal circulation becomes visible (capillary nonperfusion, proliferative vascular structures), whereby the extent of the perfusion is proportional to the brightness of the imaged vessel; the brighter the vessels or capillaries, the higher the blood flow inside the vessels. Retinal areas with low capillary flow are "dark" and show no visible vessel. In imaging of an eye with central retinal artery occlusion, retinal arterioles, veins, or capillaries were invisible due to the lack of retinal perfusion. Only ciliary-source vessels of the optic nerve head were bright and visible, indicating normal ciliary circulation. SLDF facilitates the visualization of perfused retinal capillaries and vessels in high resolution. The representation of the function of the retinal circulation by SLDF leads to an image similar to the anatomical situation. The two-dimensional mapping of local blood flow leads to a physiological picture of the retinal perfusion with visible vessels and capillaries.

Retrieval of a disconnected ventriculoperitoneal shunt catheter by laparoscopy in a newborn child: case report.

In rare cases the peritoneal catheter of a ventriculoperitoneal shunt dislodges from the valve and the peritoneal tube migrates into the peritoneal cavity. For retrieval of the free intraperitoneal shunt, tube laparoscopy is the initial method of choice.

[2-dimensional mapping and retinal and papillary microcirculation using scanning laser Doppler flowmetry]. / Zweidimensionale Kartierung der retinalen und papillären Mikrozirkulation mittels Scanning-Laser-Doppler-Flowmetrie.

PURPOSE: To present clinical applications of a new non-invasive method imaging in a high-definition the topography of perfused retinal vessels. METHOD: By a combination of a laser Doppler flowmeter with a scanning laser system the perfusion of the retina and the optic nerve head is visualized and quantified. The principles of measuring blood flow by Laser Doppler Flowmetry are based on the optical Doppler effect: laser light scattered by a moving particle is shifted in frequency by an amount delta f. Our data acquisition and evaluation system is a modified laser scanning tomograph. The technical data are: retinal area of measurement 2.7 mm x 0.7 mm, 10 degree-field with 256 points x 64 lines, measurement accuracy 10 microns, wavelength 670 nm and 790 nm, light power 100 microW, data acquisition time 2,048 s. Every line is scanned 128 times by a line-sampling rate of 4,000 Hz. By performing a discrete Fast Fourier Transformation over 128 intensities of each retinal point the laser Doppler-shift is calculated for each retinal point. With these data a 2-D map with 256 x 64 points of the retinal perfusion is created. The brightness of the picture-point is coded by the value of the Doppler shift. We estimated the reliability and the validity of the method. Perfusion-pictures of the superficial retinal layer and in the optic nerve head were presented. RESULTS: The reliability-coefficients r1 of "Flow", "Volume" and "Velocity" were 0.85, 0.83, and 0.85 respectively. The blood flow measurements by the presented method ("Scanning Laser Doppler Flowmetry") in an artificial capillary gave a linear relationship (r-value 0.973, p < 0.00001) between defined blood velocities and the measured blood flow. By the confocal technique, dependent on the focus, capillaries of the retinal superficial vasculature of the optic nerve head became visible with a high resolution. Off line the blood flow of areas of 110 microns x 110 microns were calculated in terms of laser Doppler flowmetry. CONCLUSION: "Scanning Laser Doppler Flowmetry" facilitates the visualisation of perfused retinal capillaries and vessels in high resolution. The representation of the function of the retinal circulation by SLDF leads to an image similar to the anatomical situation. The 2-dimensional mapping of local blood flow leads to a physiological picture of the retinal perfusion with visible vessels and capillaries.

Embolic complications of calf thrombosis following total hip arthroplasty.

The incidence of clinically significant pulmonary embolism following total hip arthroplasty is reported in patients with venographically documented deep venous thrombosis. One hundred seventy-four patients who enrolled in a prospective evaluation of deep venous thrombosis prophylaxis underwent contrast venography 7-10 days after operation. Ten patients with proximal and 12 patients with isolated deep calf thrombosis were identified on routine venogram reading and received appropriate anticoagulant therapy, including a 6-12-week course of warfarin. There were no clinically evident embolic events and no bleeding complications in this group. A secondary blinded review of venograms several weeks later identified isolated deep calf thrombi in 13 other patients, none of whom had received warfarin after discharge. Four of the 13 patients (P < .02) subsequently presented with pulmonary embolism at a mean of 33.5 days after operation. Asymptomatic deep calf venous thrombosis following total hip arthroplasty is associated with a significant risk of developing clinically evident pulmonary embolism within the first 8 weeks after operation. Once identified, these thrombi were effectively managed with outpatient warfarin anticoagulation, and both embolic and bleeding complications were avoided. This study documents the need for more prolonged routine prophylaxis against venous thrombosis than has heretofore been the rule, extending beyond the time of discharge from the hospital. Alternatively, the authors' experience supports the use of routine screening venography following total hip arthroplasty to allow detection and selective anticoagulant treatment of deep venous thrombosis in both the thigh and calf.

[Effect of form elasticity of the prosthesis shaft in response to stress of the proximal femur]. / Der Einfluss der Formgebung des Prothesenschaftes auf die Beanspruchung des proximalen Femurs.

Uncemented hip prostheses are characterized by a variable design of the stem. In these investigations, nine different prostheses were studied according to the model of a standard bone (Kunststoffnormfemur). After preparation of the cavity of the prostheses with original instruments and after its implantation, strain gauges were placed at 16 certain points. Measurements were carried out in steps of 200 N until reaching the maximal force of 2kN. Prostheses that are characterized by an anatomical design of the stem resemble the physiological nature of normal bone, in contrast to the models with a rectangular cross-section or with a stretched lateral shape of the stem.