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Biomedical subjects

K G Schmidt

Publications and source records attributed to K G Schmidt.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Ocular pulse amplitude and local carbonic anhydrase inhibition].

UNLABELLED: Ocular perfusion is increasingly being discussed in the pathogenesis of glaucoma. The present study was designed to investigate ocular pulse amplitude (OPA) in primary open-angle glaucoma (POAG) patients with elevated intraocular pressure (HTG) and non-glaucomatous controls (CTL) following topical application of the carbonic anhydrase inhibitor dorzolamide. METHODS: OPA (Ocular Blood Flow System, OBF Labs UK) intraocular pressure (IOP), heart rate (HR), and systolic (BPsyst) and diastolic (BPdiast) bronchial artery pressures were measured before and 2 days after initiating treatment in 33 cataract patients with n = 14) and without (n = 19) POAG. RESULTS: Following application of dorzolamide, IOP (mmHg) in drug-treated HTG and CTL eyes was highly significantly reduced (p < 0.001) and in vehicle-treated HTG and CTL eyes significantly reduced (p < 0.03) compared to respective baseline measurements. OPA (mmHg) in drug-treated HTG and CTL eyes was significantly increased (p < 0.05) and in vehicle-treated eyes in affected compared to respective baseline measurements. Systemic perfusion parameters were also unchanged. CONCLUSION: Dorzolamide increased OPA in HTG and CTL eyes. An increase in OPA may improve the prognosis of HTG.

Adult↗
PubMed1997

Influence of panretinal photocoagulation on the ocular pulse curve.

PURPOSE: To study the ocular pulsation amplitude (an indicator of choroidal circulation) and systolic ophthalmic artery pressure after panretinal photocoagulation. METHODS: Prospectively, in 10 patients with diabetes mellitus (eight with type II and two with type I; mean age, 64 years) and severe, hitherto untreated, bilateral proliferative diabetic retinopathy, we performed intensive, unilateral panretinal photocoagulation with 1,500 argon laser burns (spot size, 500 microm) in two sessions (interval, 3 weeks). Before and (in 3-week intervals) up to 9 weeks after treatment, we recorded ocular pulse curves using oculo-oscillodynamography and determined each patient's ocular pulsation amplitude and systolic ophthalmic artery pressure. RESULTS: Compared with the untreated contra-lateral eyes, panretinal photocoagulation led to a reduction of ocular pulsation amplitude. Three weeks after the first coagulation, the reduction averaged 20%. Maximum reduction was found 9 weeks after onset of treatment (6 weeks after the second coagulation) and amounted to 29.9%. The differences between photocoagulated and untreated eyes were highly significant on average (P < .01; analysis of variance) as well as for time course (P < .001). Systolic ophthalmic artery pressure was not changed significantly during panretinal photocoagulation follow-up. CONCLUSIONS: Ocular pulsation amplitude is determined by the cardiac cycle-related intraocular volume changes that depend predominantly on choroidal blood flow. The morphologic substrate is probably choriocapillary closure after photocoagulation.

Adolescent↗
PubMed1997

Spinal cord protection using hypothermic cardiocirculatory arrest in extended repair of recoarctation and persistent hypoplastic aortic arch.

OBJECTIVE: In recurrent coarctation collateral circulation may not be sufficient to maintain adequate perfusion of the lower body during the period of surgical repair. Different techniques such as interposition of a Gott-shunt, use of left heart bypass or hypothermic cardiocirculatory arrest are used to prevent spinal cord injury. METHODS: Twenty-eight operations for recurrent coarctation were performed in 26 patients following end-to-end anastomosis (58%), patch plasty (21%), subclavian flap aortoplasty (14%) and graft interposition (7%). Associated cardiac defects were present in 77% of the patients. Eleven patients who had adequate (> 50 mmHg) distal perfusion pressure during a test occlusion were operated on using simple cross-clamping (group I, mean age 8.5 +/- 3.8 years). In group I, end-to-end anastomosis was performed in nine patients and graft interposition in two patients. In 17 cases (including two patients from group I) with insufficient collateral circulation and with persistent hypoplasia of the arch, hypothermic cardiocirculatory arrest was used (group II, mean age 12.8 +/- 9.6 years). In group II end-to-end anastomosis was performed in three patients and graft interposition in 14 patients. Mean bypass-time was 116 +/- 36 min and arrest-time 33 +/- 16 min. Hypothermic cardiocirculatory arrest was begun when nasopharyngeal temperature was below 20 degrees C, corresponding to a rectal temperature of 24 +/- 3 degrees C. RESULTS: Hypothermic cardiocirculatory arrest allowed open reconstruction of the arch and/or complete or partial replacement of the arch and the coarctation segment. In-hospital mortality was 0 and 5.9% in group I and II, respectively. The one patient who died in group II had simultaneous correction of an anomalous pulmonary venous connection and death was unrelated to the method of coarctation repair. Reversible laryngeal nerve paresis was observed in two patients in group II, no other neurologic complications were observed in either group. Postoperative gradients over the repair site were less than 20 mmHg by Doppler-echocardiography. Two patients of group I had to have a second, early reoperation because of stenosis at the anastomotic site. Reconstruction of the distal aortic arch was then performed during hypothermic cardiocirculatory arrest. CONCLUSIONS: The use of hypothermic cardiocirculatory arrest in this special indication is a safe method which allows open reconstruction of the coarctation site and the aortic arch and protection of the spinal cord. The need for early reoperation because of inadequate repair may be reduced.

Anastomosis, Surgical↗
PubMed1997

Reduced ocular pulse amplitude in low tension glaucoma is independent of vasospasm.

PURPOSE: A vascular basis for the pathogenesis of primary open angle glaucoma has been postulated for many years. Defects in the regulation of ocular blood flow may be the initiating factor in this group of multifactorial diseases. This study was designed to evaluate the effect of vasospasm on ocular pulse amplitude (OPA) in low tension glaucoma (LTG) patients. METHODS: OPA, using the Langham Ocular Blood Flow (OBF) System, applanation intraocular pressure (IOP), systemic blood pressure and heart rate were measured and vasospasm was determined by a fingernail capillary blood flow test. RESULTS: OPA (mmHg) in the LTG patients with a vasospastic reaction (LTG-V, 1.4 +/- 0.1, n = 17) was not significantly (p > 0.09) different when compared with non-vasospastic LTG patients (LTG-NV, 1.5 +/- 0.2, n = 15) but was significantly (p < 0.001) reduced in LTG-V and LTG-NV patients when compared with matched healthy control subgroups (2.3 +/- 0.2 and 2.4 +/- 0.3, respectively). IOP (mmHg) in LTG-V (13.3 +/- 0.4) and LTG-NV (13.2 +/- 0.5) patient groups was not significantly (p > 0.05) different when compared with each other, but was significantly (p < 0.05) lower when compared with matched control subgroups (15.0 +/- 0.3 and 15.2 +/- 0.4, respectively). Haemodynamic parameters were not significantly different from controls. CONCLUSION: The abnormality in choroidal perfusion indicated by a reduction in OPA in all LTG patients is unrelated to the presence or absence of vasospasm.

Adult↗
PubMed1997

[Effect of nifedipine on ocular pulse amplitude in normal pressure glaucoma].

BACKGROUND: Ocular pulse amplitude (OPA) is reduced in normal tension glaucoma (NTG) patients when compared to non-glaucomatous, healthy control subjects. This might be related to a vasospastic reaction. The objective of this study was to determine if low OPA in NTG is associated with a vasospastic reaction and its response to vasodilation. METHODS: Nifedipine, a calcium channel blocker, vasodilator and systemic antihypertensive agent improves visual fields in NTG patients following acute and chronic dosing. The effect of 60 mg of daily orally administered nifedipine on OPA, intraocular pressure (IOP, German abbreviation: IOD), blood pressure (BP, German abbreviation: RR) and pulse rate (PR, German abbreviation: HF) were measured prior to and for 3 months after initiating nifedipine therapy in 32 NTG patients with and without a vasospastic reaction as manifested by a local cold exposure test. Before treatment, all patients had reduced OPA evaluated with the Langham Ocular Blood Flow System. RESULTS: During nifedipine treatment NTG patients with a vasospastic reaction showed a significant (p < 0.001) increase in OPA, whereas NTG patients without a vasospastic reaction showed no sig. (p > 0.05) change in OPA. CONCLUSION: There may be two different subgroups of NTG patients, those who have a vasospastic reaction and react to nifedipine, while others lack the ability to react to nifedipine or might have a different, non-vasospastic pathology. Calcium channel blockers and other vasodilators may be useful in the treatment of vasospastic NTG patients.

Administration, Oral↗
PubMed1997

A new method for direct detection of heparin on surface-modified intraocular lenses. A modification of Jaques' toluidine blue staining method.

BACKGROUND: Examination of surface-bound heparin on synthetic polymers can only be performed by few staining methods. These methods are limited by an only approximate detection of heparin visible at high magnification. Other methods only measure heparin quantitatively (per square dimension) and are rather sensitive to artifacts. Due to its homogeneous staining pattern, the modified toluidine blue staining technique, using a non-protein-based substance, allows examination and analysis of the homogeneity of the monomolecular heparin layer even under critical conditions like scanning electron microscopy. MATERIALS AND METHODS: For critical examination of the heparin layer, this method was used for 5 sterile heparin surface-modified (HSM) monofocal (Pharmacia, 809C, 5 mm optical zone), 2 multifocal PMMA (Pharmacia, 811E, 6 mm optical zone) and 1 standard PMMA intraocular lenses (IOLs; Pharmacia, 809P, 5 mm optical zone). A special mixture containing a sodium borate buffer was used to avoid cross-reactions of toluidine with phenylimines, which permit a covalent surface linkage of heparin to synthetic polymeric materials via reductive amination. This resulted in less coarse-grained complex agglutination. After light and spectral microscopy of the surface of stained IOLs, scanning electron microscopy was performed to investigated the reliability and validity of this modified staining method. RESULTS: All HSM IOLs showed a homogeneous heparin structure and coating, which could be demonstrated even under critical photographic circumstances. CONCLUSIONS: The modification of the original toluidine blue staining method introduced by Jaques in 1943 is a reliable and reproducible technique for the detailed in vitro analysis of surface-bound heparin with a low artifact rate. Because of the detailed detection of heparin on polymeric surfaces, this staining method is recommended for special problems, e.g. in cataract surgery.

Coloring Agents↗
PubMed1997

Transient secondary hypothyroidism in children after cardiac surgery.

Thyroid hormone status was assessed in 132 children with congenital heart defects undergoing cardiac surgery (median age 3.1 y; range 2 d to 16.2 y). Plasma TSH, thyroxine (T4), free thyroxine (fT4), triiodothyronine (T3), reverse triiodothyronine (rT3), thyroglobulin (Tg), and urinary iodine excretion were measured before and every other day after cardiac surgery (d 1-21). After surgery we observed strikingly low plasma concentrations of TSH (0.4 mU/L; 0.2-1.3), T3 (0.6 nmol/L; 0.3-1.2), T4 (48.9 nmol/L; 12.9-82.4), IT4 (12.9 pmol/L; 5.1-19.3), and Tg (9.4 micrograms/L; 1.5-20.6), whereas rT3 plasma concentrations increased (0.13 pmol/L; 0.05-0.3; n = 40). The maximal post-operative changes of TSH and rT3 preceded changes of T3, T4, fT4, and Tg. Postoperative urinary iodine excretion increased significantly (n = 109). Thyroid hormone plasma concentrations were lowest after cardiopulmonary bypass operations and in patients treated with dopamine. In patients with postoperative T3 plasma concentrations less than 0.6 nmol/L (n =52) the period of mechanical ventilation and intensive care treatment was significantly prolonged. Furthermore, the cumulative doses of inotropic and vasoactive catecholamines and furosemide were significantly higher in this patient group. Our results demonstrate transient secondary hypothyroidism in children after cardiac surgery that may contribute to postoperative cardiac and respiratory dysfunction and may delay recovery. Possible benefits of thyroid hormone replacement therapy need to be thoroughly examined.

Acute Disease↗
PubMed1996

Assessment of flow events at the ductus venosus-inferior vena cava junction and at the foramen ovale in fetal sheep by use of multimodal ultrasound.

BACKGROUND: Previous techniques for the study of the fetal circulation did not permit assessment of phasic events associated with the cardiac cycle. We used multimodal ultrasound techniques to examine flow events that occur in the major veins and across the foramen ovale in the circulation of the fetal lamb. METHODS AND RESULTS: We studied eight fetal lambs instrumented with catheters in the superior and inferior venae cavae and a peripheral umbilical vein and performed ultrasound studies that included M-mode and two-dimensional imaging, pulsed and Doppler color flow ultrasound, and contrast echocardiography to evaluate flow in the ductus venosus, in both venae cavae, and through the foramen ovale. Two blood streams of different flow velocities were identified within the cephalic portion of the inferior vena cava. The stream that originated from the narrowed ductus venosus had a higher velocity than that from the caudal inferior vena cava (mean velocity, 57 +/- 13 versus 16 +/- 3 cm/s; P < .0002). Facilitated by the eustachian valve and the septum primum, the ductus venosus stream preferentially passed through the foramen ovale to the left atrium. This flow occurred during most of the cardiac cycle, except for 19.6 +/- 2.3% of the cycle when the foramen ovale was closed during atrial contraction. Superior vena cava flow passed almost exclusively into the right atrium and tricuspid valve; a small amount that was refluxed from the right atrium into the inferior vena cava subsequently passed through the foramen into the left atrium. CONCLUSIONS: Visualization of fetal circulatory streaming at the venous sites by ultrasound techniques aids in understanding the function of the fetal circulation and may be helpful in detecting the human fetus that is hemodynamically compromised.

Animals↗
PubMed1996

Influence of physical exercise and nifedipine on ocular pulse amplitude.

BACKGROUND: Ocular pulse amplitude (OPA) was measured to investigate the influence of peripheral vasoconstriction and vasodilation on choroidal perfusion in healthy volunteers and to determine whether low OPA in low-tension glaucoma (LTG) patients is associated with a vasospastic reaction and its response to the calcium channel blocker nifedipine. METHODS: OPA was determined using the Langham ocular blood flow (OBF) system, applanation intraocular pressure (IOP), systemic blood pressure, and heart rate were measured, and ocular perfusion pressure was calculated before and after exercise and smoking in 12 otherwise nonsmoking, healthy volunteers and prior to and for 3 months after initiation of nifedipine therapy in 32 LTG patients with and without a vasospastic reaction as manifested by a nailfold capillary blood flow test. RESULTS: Exercise significantly (P < 0.05) increased heart rate, systolic blood pressure and ocular perfusion pressure, while it significantly (P < 0.05) reduced IOP and diastolic blood pressure. However, OPA was not significantly (P > 0.1) affected by changes in these parameters. Smoking significantly (P < 0.05) increased systolic and diastolic blood pressure, heart rate, and ocular perfusion pressure but did not significantly (P > 0.09) alter OPA. There were two distinct LTG subtypes, with and without a vasospastic reaction. Only those with a vasospastic reaction showed a significant (P < 0.001) increase in OPA after 3 months of nifedipine treatment, while all other parameters tested were not significantly altered. CONCLUSION: Despite affecting ocular and systemic perfusion parameters, exercise and smoking did not alter OPA, suggesting functional isolation, i.e. autoregulation of the choroidal and/or ophthalmic artery circulation in healthy volunteers. Low OPA in LTG was increased by nifedipine only in vasospastic LTG patients, suggesting different, vasotonus-related pathologies. Calcium channel blockers and other vasodilators may be useful in vasoreactive LTG patients with reduced OPA.

Adult↗
PubMed1996

Early increase in blood pressure and diastolic left ventricular malfunction in patients with glomerulonephritis.

In patients with diabetic nephropathy blood pressure increases progressively before the conventional threshold of normal blood pressure (140/90 mm Hg) is transgressed. In patients with glomerulonephritis, no information on this point is available. To clarify this issue we sequentially examined 20 untreated patients with biopsy-proven primary chronic glomerulonephritis (GN) who had casual blood pressure below 140/90 mm Hg and normal GFR by inulin clearance. Patients were compared with normotensive healthy controls who were matched for BMI, gender and age. We measured ambulatory 24-hour blood pressure (SpaceLab system), echocardiography (ASE criteria, Acuson 128 XP 10), CIn and CPAH, urinary Na excretion, PRA and insulin concentration. In patients with GN, the median 24 hour (P < 0.0005), daytime (P < 0.001) and nocturnal sleeping time (P < 0.0001) MAP values were significantly higher than in matched controls (daytime, mean 97 mm Hg, 85 to 106 GN vs. 89 controls range 82 to 102; nocturnal sleeping time, mean 80.3 mm Hg, 71 to 89.5 GN vs. 73 controls, range 63 to 84). Echocardiographic examination showed significantly greater posterior wall thickness (P < 0.01) and ventricular septal thickness (P < 0.003). In addition the early diastolic to late diastolic (E/A) ratio of mitral valve peak inflow velocity was significantly (P < 0.0008) lower in patients. The data point to left ventricular wall thickening accompanied by LV diastolic malfunction. The study documents elevated ambulatory blood pressure in patients with primary chronic glomerulonephritis despite normal body weight and normal GFR. This is associated with evidence of target organ damage in the heart. The findings suggest that in patients with glomerulonephritis blood pressure increases initially within the normotensive range. This observation in conjunction with evidence of early target organ changes provides an argument for early antihypertensive intervention, but controlled trials to test efficacy and safety of this proposal are necessary.

Adult↗
PubMed1996

[Effect of the vasodilator isosorbide dinitrate on ocular circulation].

BACKGROUND: Vasodilator drugs are increasingly being discussed as possible antiglaucomatous substances. Aim of the present study is to evaluate, from a hemodynamic point of view, the vasodilator drug isosorbide dinitrate (ISDN) regarding its suitability for glaucoma therapy. METHODS: 20 healthy subjects (mean age: 28 yrs) volunteered to participate in the study. In randomized order, each subject received one tablet containing 40 mg ISDN (sequels) or--in a second trial--one tablet placebo (+500 mg of the analgetic metamizol, respectively, for prophylaxis of nitrate headache). 1 h before as well as 1, 3, 5, and 7 hrs after medication, the following variables were determined using oculo-oscillo-dynamography: systolic ophthalmic artery pressure (SOAP), systolic ocular perfusion pressure (SOPP), ocular pulsation amplitude (OPA) and the product OPA x heart rate (HR). Intraocular pressure (IOP) as well as systolic and diastolic brachial artery pressures (SBAP, DBAP) were also measured. RESULTS: After administration of ISDN (+analgetic), the variables SBAP, SOAP and SOPP were significantly (p = 0.01) lowered compared to placebo (+analgetic), and also the IOP tended to be lower (p = 0.08). The maximum reduction was found 3-5 hrs after medication: SBAP 10.9 mm Hg (9%), SOAP 12.5 mm Hg (14%), SOPP 11.3 mm Hg (14.5%), and IOP 1.5 mm Hg (12%). The relation SOAP vs. SBAP was significantly (p = 0.0004) linear, the correlation coefficient amounted to 0.39. DBAP remained unchanged, HR was increased by 4-7 beats/min (p = 0.08). OPA and the product OPA x HR showed highly significant decreases by maximum values of 44% and 40%, respectively. CONCLUSION: ISDN (+analgetic) caused a reduction of SOAP and SOPP, which can be accounted for by the reduced systolic systemic blood pressure. In addition, there was a decrease of OPA and of the product OPA x HR (a measure of pulsatile ocular blood flow), which finding may be explained by a cardiac stroke volume reduction that is typical for nitrates. Due to these hemodynamic effects and due to the only weak IOP reduction, ISDN does not appear to be suitable for glaucoma therapy.

Adult↗
PubMed1996

[Minimally inflammatory cataract surgery].

BACKGROUND: Cataract surgery leads to a more or less intensive postoperative inflammation due to breakdown of the blood-aqueous barrier. In a prospective, randomized and controlled clinical trial, we examined aqueous flare as well as intraocular pressure and visual acuity after a minimally invasive cataract surgical procedure under different anti-inflammatory treatment. PATIENTS AND METHOD: In 150 patients (39-88 years of age) without glaucoma or pre-existing deficiencies of the blood-aqueous barrier, phacoemulsification through a clear-corneal tunnel incision with implantation of a 5 mm PMMA posterior chamber intraocular lens was performed. Patients were randomly assigned to one of 5 treatment groups, each consisting of 30 patients: 1) preservative-free diclofenac 0.1% eyedrops (DICpf) pre- and postop.; 2) diclofenac 0.1% eyedrops with preservative (DICp) pre- and postop.; 3) DICpf only postop.; 4) DICpf pre- and postop. in combination with dexamethasone-21-dihydrogenphosphate 0.1% eyedrops (DEXA); 5) DEXA postoperatively. For prevention of postoperative intraocular pressure (IOP) elevation, carbachol 0.01% (for intraocular application) was injected into the anterior chamber intraoperatively, and dichlorphenamide (50 mg/d per os) was applied until day 1 postoperatively. - Aqueous flare (laser flare-cell meter FC-1000), IOP (Gold-mann applanation tonometer) and best-corrected visual acuity were determined on the day before surgery as well as 6 hrs (only flare and IOP), 1 day, 3 and 7 days postoperatively. RESULTS: Aqueous flare (photon counts/ms) in treatment group 1 increased from 10.8 +/- 1.7 (means +/- SE) preoperatively to only 14.7 +/- 3.1 in the afternoon of the day of surgery. Already on day 1 postoperatively, the flare decreased to 9.3 +/- 0.9, and remained relatively constant on days 3 and 7 after surgery. The flare in group 3 (DICpf only postop.) was significantly higher (p = 0.03; ANOVA) than in group 1. There were no other significant group differences concerning flare (group 1 vs. 3;1 vs. 4;4 vs. 5). -IOP (mm Hg) dropped from 16.3 +/- 0.2 preoperatively to 15.8 +/- 0.6 already 6 hrs postoperatively (group means). On days 1 and 3, the IOP continued to drop to 13.2 +/- 0.3 and 12.7 +/- 0.3, respectively. Not before day 7, the IOP tended to increase again (14.2 +/- 0.3). The IOP showed no significant group differences. - Visual acuity increased from 0.25 +/- 0.01 preoperatively to 0.73 +/- 0.02 already on day 1 postoperatively (group means). On days 3 and 7, the acuity amounted to 0.83 +/- 0.24 and 0.92 +/- 0.02, respectively. DISCUSSION: Under the conditions of the present study (with specific pharmacological therapy and patient selection), clear-corneal phacoemulsification leads to an extremely low and short-lasting intraocular inflammation, especially under pre- and postoperative treatment with preservative-free diclofenac eyedrops. Thus, the aim of minimally inflammatory cataract surgery (MICS) is realized. As secondary phenomenon, a postoperative IOP increase, often observed in the early postoperative period, is lacking, and the visual acuity rises very fast postoperatively.

Adult↗
PubMed1995

Determination of ventricular volumes in human fetal hearts by two-dimensional echocardiography.

In conclusion, ventricular volume calculation from 2DE is feasible in the human fetus and improves the ability to calculate fetal ventricular size and ejection fraction. The right ventricle is clearly dominant at midgestation, but approaches left ventricular size at term. Calculation of the ventricular output from 2DE volume measurements is an accurate alternative to Doppler measurements.

Echocardiography↗
PubMed1995

Leukemia inhibitory factor mRNA is expressed in cortical astrocyte cultures but not in an immortalized microglial cell line.

Leukemia inhibitory factor (LIF) is a multifunctional cytokine synthesized by a variety of cell types. In the nervous system LIF affects neuronal differentiation, and may be important during cerebral infection and inflammation. To clarify the cellular source of LIF in the brain, we examined the expression of LIF mRNA by primary cortical astrocyte cultures and an immortalized microglial cell line. The microglial cell line did not express LIF mRNA in response to pro-inflammatory agents such as lipopolysaccharide (LPS) that induced expression of other cytokine mRNAs. In contrast, primary astrocyte cultures grown in serum-containing medium expressed LIF mRNA constitutively, and this expression was regulated by pro-inflammatory and anti-inflammatory stimuli. Agents which activate the cAMP and protein kinase C second messenger systems also increased LIF mRNA in astrocyte cultures. These results suggest that astrocytes, but not microglia, may be an important source of LIF during cerebral inflammation and infection.

Animals↗
PubMed1995

[Long-term outcome after silicone oil removal].

In order to reduce the incidence of postoperative complications in silicone-filled eyes, many authors recommend that silicone oil should be removed from the eye as soon as a stable retinal situation is achieved. Even in the eyes with completely attached retina and a clinically stable situation there is a risk of retinal redetachment and other complications after silicone oil removal. In a retrospective study we analyzed 324 cases after silicone oil removal regarding the postoperative redetachment rate and risk of complications from this procedure. The indication for primary surgery was retinal detachment with PVR in 167 (51.5%) cases, proliferative diabetic retinopathy in 87 cases (26.8%), complications of penetrating ocular injuries in 48 cases (14.8%), giant tear retinal detachment in 9 cases (2.7%) and retinal detachment with a central hole in 13 cases (4%). At the time of silicone oil removal retina was completely attached in 277 eyes. Local retinal redetachment central to the encircling band existed in 47 eyes at the time of silicone removal. Follow-up time ranged from 6-63 months. Silicone oil removal was combined with a cataract operation in 42 cases (12.9%), penetrating keratoplasty in 9 cases (2.8%) and membrane peeling in 54 eyes (16.7). In the postoperative period the retina detached in 39 (12%) eyes. In the eyes with preoperatively completely attached retinas, redetachment occurred in 23 eyes (8%), whereas in the group of eyes with an unstable preoperative retinal situation, the retina redetached in 16 eyes (34%). The duration of the silicone oil tamponade had no effect on the redetachment rate. In the group of eyes with an unstable preoperative retinal situation, preoperative laser photocoagulation at the cerelage buckle, as well as central to the local detachment, reduced the incidence of redetachment after silicone oil removal significantly (25% vs. 53%). In the group of eyes with a preoperatively stable retinal situation, this effect was not significant. Our results show that in eyes with completely attached retinas, the risk of complications and redetachment after silicone oil removal is relatively low. In selected cases, even in eyes with incompletely attached retinas, silicone oil could be removed. Nevertheless, a relatively high risk of postoperative complications has to be taken into consideration. In eyes with an incompletely attached retina, preoperative laser photocoagulation at the cerclage buckle, as well as central to the local redetachment significantly reduced the incidence of redetachment after silicone oil removal.

Adult↗
PubMed1994

Studies of the ocular pulse in primates.

Ocular pulse amplitude (OPA) and intraocular pressure (IOP) were measured in groups of human subjects with primary open-angle glaucoma (POAG), ocular hypertension (OHT), low-tension glaucoma (LTG), retinal degenerations (RD), in OHT volunteers treated with single doses of 2% epinephrine, 4% pilocarpine, 0.5% timolol or 1% p-amino-clonidine, and in normal subjects before and after exercise. Compared to normal controls, OHT subjects showed significantly higher IOP and OPA, while OPA was significantly lower in ocular normotensive LTG and RD subjects groups. All drug treatments lowered IOP in OHT subjects, but did not change OPA significantly. Exercise in normal volunteers increased calculated ocular perfusion pressure by 22.5%, lowered IOP by 32%, but showed no significant change in OPA. When IOP was elevated > or = 5 mmHg in lasered monkey eyes peak pulse volume (PPV) was increased significantly in the unlasered eyes. Epinephrine 2% or 1% p-aminoclonidine lowered IOP moderately with no change in PPV, while treatment with 4% pilocarpine or 0.5% timolol reduced IOP and increased PPV significantly. The findings suggest that LTG may be associated with an ocular vascular abnormality. OPA in OHT or normal human subjects did not change when IOP was decreased by antiglaucoma drug treatments or exercise, respectively. These results indicate that OPA may be physiologically autoregulated in human subjects with IOPs in the 11-21 mmHg range. However, laser-induced glaucomatous monkey eyes with higher IOP (30-35 mmHg) did not autoregulate, but showed a low peak pulse volume, which increased when IOP was reduced 5 mmHg or more by means of antiglaucoma drug treatment.

Adult↗
PubMed1993

Elevated blood pressure profile and left ventricular mass in children and young adults with autosomal dominant polycystic kidney disease.

Twelve children (< 15 yr) and 12 young adults with autosomal dominant polycystic kidney disease (ADPKD) confirmed by ultrasonography and 24 nonaffected individuals matched for age, sex, and body surface area were examined with ambulatory blood pressure monitoring and echocardiography. All patients and controls had normal renal function (median serum creatinine, 0.85 mg/dL; range, 0.5 to 1.1). In children, daytime and nighttime blood pressures were not significantly different from those of controls; the median left ventricular mass index (in grams per square meter) was higher in patients (66.6 g/m2) than in controls (61.3 g/m2; P < 0.002), although all values remained within the normal range. In young adults with ADPKD, mean arterial blood pressure was significantly higher than that in controls both during daytime (98.3 mm Hg; range, 74 to 126 versus 90.6 mm Hg; range, 73 to 116; P < 0.006) and during nighttime (83.2 mm Hg; range, 66.5 to 125 versus 79.0 mm Hg; range, 63 to 91; P < 0.05). In parallel, the median left ventricular mass index was significantly higher in young adults (81.8 g/m2; range, 62 to 174 versus 64.3 g/m2; range, 52 to 102; P < 0.02). The results document that ambulatory daytime and nighttime blood pressures and left ventricular mass indices are higher in asymptomatic carriers of the ADPKD trait compared with controls, although most values are still within the normal range.

Adolescent↗