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Biomedical subjects

Z Gregor

Publications and source records attributed to Z Gregor.

At least 37 records · Page 2Linked to original sources
PubMed1997

Broad laser indentation surface for retinal laser photocoagulation using indirect ophthalmoscopic delivery.

Laser photocoagulation of the peripheral retina is an important part of the therapeutic options for treating many vitreoretinal disorders, such as diabetic retinopathy, retinopathy of prematurity, and vitreoretinal degeneration. When preequatorial retinal photocoagulation is required, indirect delivery of laser energy is preferable, whether applied in the office setting or as part of a sterile surgical procedure. The anterior retina is usually visualized by scleral indentation employing a conventional scleral indentor or muscle hook. Under these circumstances the retinal surface presented frequently is too small and irregular, making efficient laser delivery unnecessarily laborious, resulting in a variable uptake of laser energy.

Equipment Design↗
PubMed1997

Choroidal metastases from renal cell carcinoma.

BACKGROUND: Choroidal metastases from renal cell carcinoma are uncommon. The authors investigated the clinical characteristics of patients with renal cell carcinoma in whom choroidal metastases developed. METHODS: The clinical records of five patients with histopathologically confirmed renal cell carcinoma and choroidal metastases were reviewed retrospectively. RESULTS: In four patients, choroidal metastases were either the sole initial manifestation of disease or were the initial manifestation of metastatic disease. The interval from nephrectomy to the onset of ocular signs ranged from 6 to 18 years. A reddish-orange appearance of the tumor was present in two patients, but no pathognomonic features distinguishing these tumors from other choroidal metastases were identified. CONCLUSIONS: Ocular metastases may precede the diagnosis of renal cell carcinoma or may follow it by years or decades. This interval between its ocular and systemic presentation may be so prolonged as to obscure the relation between the choroidal metastases and the primary tumor. In patients with amelanotic or reddish choroidal lesions without known metastatic disease, evaluation of the kidney may be warranted as part of a metastatic workup to exclude metastatic renal cell carcinoma.

Aged↗
PubMed1997

Intravitreal growth factors in proliferative diabetic retinopathy: correlation with neovascular activity and glycaemic management.

AIM: Many growth factors are implicated in proliferative diabetic retinopathy (PDR). It was decided to test the hypothesis that no one factor is predominant but that a regular profile of levels of different growth factors might be operating, and that the profile might differ according to whether or not insulin therapy was part of the patient's glycaemic management. The levels of several growth factors in vitrectomy samples were therefore determined from diabetic patients with tractional, non-haemorrhagic sequelae of PDR and these levels were correlated with (a) each other (growth factor profile), (b) neovascular activity, and (c) the method of glycaemic management (insulin treated (IT) or non-insulin treated (NIT)). METHODS: 72 samples of vitreous were obtained from either diabetic patients with PDR (n = 51) or non-diabetic (control) patients (n = 21). Levels of bFGF, IGF-I, EGF, and insulin were determined by radioimmunoassay; levels of TGF-beta 2 by ELISA; and levels of IGF-I binding protein by western ligand blotting. The data were analysed using appropriate statistics. RESULTS: There was no regular growth factor profile. bFGF levels were significantly greater in vitreous from NIT patients compared with IT patients and controls. The highest levels of bFGF were found in NIT patients with actively vascularised membranes. TGF-beta 2 levels were significantly greater in vitreous from IT patients compared with NIT patients and controls The highest levels of TGF-beta 2 were found in IT patients with actively vascularised membranes. IGF-I levels were significantly greater in diabetics (irrespective of insulin treatment) than non-diabetics and the highest levels of IGF-I were found in IT patients with actively vascularised membranes. A 34 kDa IGFBP was the predominant IGFBP identified in vitreous and was found to be elevated in diabetics patients. CONCLUSION: In PDR there is a correlation between intravitreal growth factor levels and both disease state (whether active or fibrotic) and method of glycaemic management.

Analysis of Variance↗
PubMed1997

[Resection of the first rib for the upper thoracic outlet syndrome-- long-term experience].

The authors describe their own experience with the surgical treatment of the upper thoracic aperture syndrome-TOS-during the period of 14 years. During this period on account of this diagnosis at the Surgical Clinic in Brno 112 patients were operated, whereby the resection of the first rib was always done by the transaxillary approach. The authors describe in detail the symptomatology, diagnosis and surgical treatment. They emphasize the advantages of the transaxillary approach. In the conclusion the authors discuss the fact that only in 45% of the operated patients the symptoms disappeared. This leads to reflections on more strict criteria for the surgical treatment of this syndrome.

Humans↗
PubMed1997

[Carotid-subclavian bypasses (1985-1996)].

A carotic-subclavian bypass is an extraanatomical reconstruction. It is one of the possibilities how to connect the ipsilateral common carotid and subclavian artery. The authors evaluate carotic-subclavian bypasses made during the past 11 years at the Second Surgical Clinic in Brno. In all twelve cases carotico-subclavian bypasses were involved, in none of the patients a subclavian-carotid bypass was involved or direct anastomosis. The author discusses in detail preoperative complaints, associated diseases, postoperative complaints. In his opinion absolute indications for surgery are neurological symptomatic affections even of one trunk, incl. subclavian steal syndrome. They indicate asymptomatic affections for surgery if at least two trunks are affected. The greatest pitfall of the operation is in their opinion the selection of the length and type of vascular prosthesis. They find that the interval patency rate 100% and the cumulative patency rate 85% evaluated by the method of "Life table analysis" with a standard error of patency rate of 9% are comparable with similar reports from abroad.

Blood Vessel Prosthesis Implantation↗
PubMed1997

[Aneurysm of the splenic artery].

The authors describe in their paper possibilities of surgical and intervention treatment of an aneurysm of the lienal artery, their advantages and disadvantages. They evaluate the results of treatment of aneurysms of the lienal artery in three patients treated at the Second Surgical Clinic in Brno in 1993-1996. In the first patient the aneurysm was resected concurrently with splenectomy. In the second patient resection of the aneurysm with end to end anastomosis of the lienal artery was made. In the third patient the method of artificial embolization of the aneurysm of the lienal artery was used. The results are good. The first two patients were discharged ten and nine days resp. after surgery and are in a good clinical condition. The third patient had treatment in four sessions within two months and the final effect is a completely embolized aneurysm of the lienal artery with a preserved blood supply of the spleen and its intact function. The authors maintain that when dealing with an aneurysm of the lienal artery the surgeon has several possibilities and it is up to him which possibility he will chose with regard to anatomical conditions, the patients general condition and his own abilities and possibilities. The authors recommend if possible to preserve the spleen as a functioning organ or to preserve at least its immunological function.

Aged↗
PubMed1997

[Embolisms of the abdominal aortic bifurcation].

The authors evaluate in the submitted paper the results of surgical treatment of embolization into the bifurcation of the abdominal artery at the Second Surgical Clinic in Brno during 1990-1996. A total of 5 patients was involved whereby in all a cardiac cause of the embolization was obvious. The authors deal also with the time which has elapsed between the development of complaints and surgery, the type of anaesthesia, average length of operation. The operation is implemented concurrently by two teams as antero- and retrograde simultaneous bi-transfemoral embolectomy. The authors emphasize the importance of the metabolic condition of the patient as well as cardiac and renal functions before, during and after surgery. They consider the application of peroperative haemodialysis essential. During the postoperative period it is important to find the objective cause of the cardiac deficiency and treat it. Their results--a 40% mortality are comparable with those of other specialized departments. By comparison with a similar group treated at the same department twenty years previously the authors find a decline in the incidence of this disease and explain this phenomenon by an increased number of cardiosurgical operations in this area.

Aorta, Abdominal↗
PubMed1995

Recurrent acute multifocal placoid pigment epitheliopathy in two cousins.

PURPOSE/METHODS: To test the hypothesis that there may be inherited predisposition in acute multifocal placoid pigment epitheliopathy, HLA typing was undertaken in two cousins with recurrent disease. RESULTS/CONCLUSIONS: Both cousins were shown to have HLA antigens DR2 but not B7; both antigens have been associated with this disorder previously. This finding is compatible with the concept that DR2 may be associated with an increased risk of recurrent disease.

Acute Disease↗
PubMed1994

Cytokeratin-containing cells in proliferative diabetic retinopathy membranes.

Immunohistochemical techniques were used to investigate the relation between retinal pigment epithelial cells (RPE), traction retinal detachment (TRD) membranes, and combined traction rhegmatogenous retinal detachment (CTR) membranes in proliferative diabetic retinopathy. Seven CTR and five TRD membranes were obtained during closed microsurgery. Six of the seven CTR membranes and one of the five TRD membranes contained RPE. Eleven of the 12 diabetic membranes incorporated glial cells. The findings emphasise that the intravitreal membranes of proliferative diabetic retinopathy contain a diversity of cell types and indicate that RPE tend to contribute to CTR, rather than TRD, membranes. The histopathological appearance of CTR membranes is that of a hybrid between TRD and proliferative vitreo-retinopathy membranes.

Diabetic Retinopathy↗
PubMed1992

Spontaneous relieving retinotomies in diabetic silicone filled eyes.

We describe in six patients the delayed occurrence of inferior tractional retinal detachments following epiretinal reproliferation 4 to 5 months after vitrectomy and silicone oil tamponade for diabetic related retinal detachments. The epiretinal traction was spontaneously relieved by the occurrence of large inferior tension breaks which subsequently enlarged and coalesced to form retinotomies. This process appears to be relatively benign as it remains limited to the peripheral retina, and in all six patients the posterior retina has remained attached for a minimum of 12 months follow up, with improved central visual acuity.

Adult↗
PubMed1992

Fibronectin synthesis in subretinal membranes of proliferative vitreoretinopathy.

In situ hybridisation and immunohistochemical studies were conducted on six surgically excised subretinal membranes of proliferative vitreoretinopathy to investigate whether displacement of retinal pigment epithelial and glial cells to subretinal membranes was associated with fibronectin production by the subretinal membrane cells. Fibronectin messenger RNA (mRNA) and fibronectin immunoreactivity were observed in some cells in all of the subretinal membranes studied and up to 30% of the cells in individual specimens showed intense labelling for fibronectin mRNA. The results support the concept that the cells in subretinal membranes produce fibronectin. Locally produced fibronectin may play a role in subretinal membrane cohesion, and displacement of retinal pigment epithelial and glial cells from their normal location may induce the cells to manufacture fibronectin. Fibronectin production may be more prominent in migrating subretinal cells.

Eye Diseases↗
PubMed1991

Ophthalmological screening for von Hippel-Lindau disease.

Forty seven individuals (from 16 kindreds) without prior evidence of retinal haemangiomas underwent full ophthalmological assessment as part of a comprehensive screening programme for Von Hippel-Lindau disease. Ten were known to be affected on the basis of non-ocular involvement and 37 were at 50% risk of having the abnormal gene. Seventeen angiomas were detected in 14 individuals (six affected patients and eight at risk relatives). Regular detailed ophthalmological assessment is important for all patients with von Hippel-Lindau disease and for relatives at risk of inheriting the abnormal gene.

Adult↗
PubMed1991

Panretinal laser photocoagulation for proliferative diabetic retinopathy: the effect of laser wavelength on macular function.

The effect on macular function of the wavelength of laser light used to treat proliferative diabetic retinopathy was studied. Thirty-six eyes of 25 patients received panretinal photo-coagulation according to a standardised protocol and before and at intervals after the treatment were tested by a battery of macular function tests. Each eye was randomly assigned to treatment with blue-green, yellow, or orange laser. The tests included best corrected visual acuity, colour vision, contrast sensitivity, macular threshold, and central visual fields. There were no significant differences in the results of these tests between the three treatment groups, though there was wide scattering of baseline values within each group. Laser wavelength has not been shown to be an important determinant of central visual function following panretinal photo-coagulation in patients with proliferative diabetic retinopathy within the wavelengths tested.

Adult↗
PubMed1991

[Problems in indications for vascular reconstructive surgery].

The authors discuss examinations made before a planned vascular reconstruction operation. As the number of vascular reconstruction operations is steadily increasing, and the operations affect the entire organism, and the operations are associated with a relatively high mortality rate, the authors try to reduce the latter by the correct classification into a risk group, select the correct order of surgical operations, and last not least, on the basis of these conclusions they try to define also the surgical procedure proper during reconstruction. As atherosclerotic affections can be isolated or combined, the authors divide the patients into three groups. The first group can be subjected to a reconstruction operation without special preparation. The second group comprises patients where it is either necessary to confirm or rule out affection of extracranial cerebral arteries and the third group comprises patients where it is necessary to confirm or rule out affection of the coronary arteries. The aim of this comprehensive procedure is to reduce as much as possible the surgical mortality.

Adult↗
PubMed1990

Evaluation study of calves with total artificial heart (TAH) surviving for 218-293 days of pumping.

Evaluation of five longest surviving calves among a total of 54 longterm survivors, at the Brno Research Centre was performed. These calves were treated by administration of antihypertensives and partially by electrical stimulation of the right atrium to reduce central venous pressure (CVP). Treatment for CVP was effective, as compared with two groups of 5 calves each not treated in this way, and it is assumed to be an important factor for prolongation of survival. Mineralization of driving diaphragms was present in all these calves. No preventive measures of this pathologic change were performed in this group. Another complication is hemolysis, which is partly caused by immune mechanisms initiated by administration of alpha-methyl dopa and partly by mechanical destruction due to a heavily mineralized driving diaphragm. The prevention of mineralization is another important problem for future research. Other problems, concerning the survival of TAH recipients are discussed.

Animals↗
PubMed1989

[Therapy of venous hypertension in animals with an artificial heart and long-term survival].

1. The authors elaborated an original concept for the interpretation of vasomotor disorders in subjects with an artificial heart. 2. This concept is based on the regeneration of nervous elements in the walls of the atria (in particular the right one) after implantation of the artificial heart and on comparison of their activity with the venous pressure which revealed the interrelationship of the two phenomena. 3. Both therapeutic methods based on this concept, the method of influencing the afferentation and efferentation of vasomotor nervous regulations leading to a reduction of the central venous pressure proved valid and effective. 4. Evaluation of the effectiveness of this therapy is based on regular assessment of the central venous pressure, on the laboratory assay of enzymes (AST, ALT, GMT and LDH), on the assessment of serum albumin and finally on the morphological and histological examination of the liver incl. assessment of the hepatic index. 5. The nervous pathogenesis is closely linked with hormonal factors. The latter are conceived as the participation of associated factors in the pathogenesis of venous hypertension in recipients with an artificial heart.

Animals↗
PubMed1989

Cellular components of subretinal membranes in proliferative vitreoretinopathy.

To determine the cellular composition of subretinal membranes in proliferative vitreoretinopathy, surgically excised membranes were studied using electron microscopic and immunohistochemical procedures. Light microscopic immunohistochemistry was found to be superior to conventional electron microscopy as a means of evaluating the relative contributions of retinal pigment epithelium and glia to subretinal membranes. The cells of subretinal membranes chiefly comprised retinal pigment epithelium while glial cells were either absent or contributed only a minor component. It is proposed that the clinical properties of subretinal membranes in proliferative vitreoretinopathy derive from their retinal pigment epithelial cell element.

Glial Fibrillary Acidic Protein↗