Biomedical subjects

A W Fryczkowski

Publications and source records attributed to A W Fryczkowski.

At least 19 recordsLinked to original sources

PubMed1999

[Corneal wound healing after penetrating keratoplasty with EGF application. Experimental studies].

PURPOSE: To check post penetrating keratoplasty (PK) corneal wound healing characteristics after epidermal growth factor (EGF) application and to compare it with controls. MATERIAL AND METHODS: The PK was performed in the group of 72 young, healthy New Zealand rabbits (36 females and 36 males). Slit-lamp examination, tonometry and corneal topography by Tomey's corneal modeling system (TMS-1) were carried out before and after surgery. The PK was performed in both eyes. Half of animals were used as a bilateral donor for the other half, with a rule: right eye cornea to the right eye and left eye cornea to the left eye. As a result, after completed surgery 36 rabbits had bilateral grafts. The animals were divided into 3 equal groups (12 in each). Two drops of the human recombined EGF dissolved in the saline solution with concentration varied from 500 to 1500 ng in each drop were applied to the right eye according to schedule. The left eye was used as a control and did not receive EGF. Time of observation varied from 24 hours to 6 months. The tensinometry and the histopathologic study--light and electron microscopy were performed to determine corneal scarring. RESULTS: The wound healing pattern after PK was characteristic and constant in each group. The corneal wound healing significantly accelerated in the EGF treated group of rabbits compared with the controls (p < 0.05). In the group of rabbits receiving 1000 ng of hrEGF 3 times/day, after two weeks of application we noted increase of the wound strength up to 600 folds, comparing with controls. Well-organized scar was histologically seen on the 21st post-surgery day. The post-operative corneal astigmatism was less expressed in the eyes treated with EGF comparing to controls. CONCLUSIONS: These preliminary results of our experimental study indicated accelerated effect on the corneal wound healing after PK with topical, low dose hrEGF application. Clinical observation of utilization of similar low doses of the hrEGF after PK--is in progress.

Animals↗

PubMed1995

Variability in choriocapillaris blood flow distribution.

PURPOSE: To investigate variability of choriocapillaris blood flow patterns. METHODS: After the intravenous injection of indocyanine green, angiograms were recorded at 30 images per second in rhesus monkey eyes using a fundus camera equipped with a pulsed laser diode light source, synchronized with a gated (5 msec), intensified charge-coupled device, or CCD, video camera. Images of choriocapillaris filling alone were extracted. Plastic corrosion casts were made of two of the monkey's choroidal vasculatures for subsequent scanning electron microscopy examination. RESULTS: Pulsed laser indocyanine green fluorescence excitation produced better definition of choriocapillaris filling than had been achieved using continuous illumination. No correlation was found between the choriocapillaris plexus architecture revealed by the plastic corrosion casts and the observed choriocapillaris lobular filling. Overall posterior pole choriocapillaris dye-filling patterns were relatively stable for periods of days, but they changed gradually for periods of weeks. Localized minor pattern changes occurred on a much shorter time scale. Choriocapillaris filling patterns were altered by acutely elevating intraocular pressure, by O2 and CO2 breathing, and by argon laser retinal photocoagulation of adjacent areas. CONCLUSIONS: Choriocapillaris filling patterns appear to be determined by the network of perfusion pressure gradients that exist among the interspersed feeding arterioles and draining venules connected to the choriocapillaris plexus. Changes in intraocular pressure and in blood PO2 and PCO2 levels can produce marked changes in the distribution of choriocapillaris blood flow. Retinal laser photocoagulation of adjacent fundus areas alters choriocapillaris blood flow to the extent that the altered flow might be an important factor in the beneficial results attributed to retinal laser treatment.

Animals↗

PubMed1994

Anatomical and functional choroidal lobuli.

The purpose of this paper is to clarify the controversy between anatomists and clinicians regarding the choroidal angioarchitecture. Vascular casts from 36 human and 10 Rhesus monkey eyes were studied using scanning electron microscopy (SEM). Both the human and monkey choriocapillaris (CC) are non-homogenous structures. They have patterns which change from the peripapillary to peripheral areas. Anatomically, the 'lobular' appearance of the CC exists only in part of the posterior pole. One or more collecting venules were found in the center of 86% of the anatomical lobules, while a central feeding arteriole was observed in 14%. Both major and minor feeding arterioles supply the CC areas which may be recognized as the choroidal functional vascular unit (CFVU) or functional lobule described in the past by Hayreh. Our vascular casts and SEM study show that the choroidal anatomical lobuli are not identical with those observed by angiographical study. Thus, two distinct models of choroidal lobuli, anatomical and functional, should be recognized. The CFVU seen on fluorescein (FA) and indocyanine green (ICG) angiographies as a lobular appearance is most likely caused by the pressure gradient of the blood flow.

Adult↗

PubMed1991

Observations on the lobular organization of the human choriocapillaris.

Vascular casts (Batson mixture) of ocular angioarchitecture were prepared from ten human orbits removed at autopsy. The age of donor specimens ranged from seven months to 68 years. The time interval between death and injection of the orbits averaged seven hours with a range of five hours. The resulting vascular casts were examined using light microscopy and scanning electron microscopy (SEM). We present photomicrographs of our vascular casts that demonstrate predictable variations of the human choriocapillaris angioarchitecture according to the region of the choriocapillaris under examination (i.e. posterior pole, equatorial, peripheral, peripapillary, or submacular areas). Our discussion represents an effort to help clarify some persistent controversies concerning the human choroidal angioarchitecture.

Adult↗

PubMed1991

Scanning electron microscopic study of microaneurysms in the diabetic retina.

We describe the clinical and pathologic appearance of the retinal microcirculation in a patient with a 22-year history of diabetes mellitus. A vascular cast of one eye was prepared and studied with scanning electron microscopy. The three-dimensional views obtained give insight into the pathogenesis of microaneurysms.

Aged↗

PubMed1990

Father Waclaw Szuniewicz, M.D., an ophthalmologist of unusual courage and devotion.

The authors present a short biography of the missionary-priest ophthalmologist Waclaw Szuniewicz (1892-1963). This remarkable man completed his ophthalmologic training between 1922 and 1927 at the Department of Ophthalmology of the Stefan Batory University in Wilno, Poland. From 1931 to 1949 he served as a missionary priest in China, and for part of this time he was the head of the Department of Ophthalmology at a hospital in the Chinese town of Shuntehfu. He organized and ran a 100 bed ophthalmology department there, also supervising 18 outpatient clinics in the surrounding area. During this period he regularly saw over 145,000 patients and performed over 5000 ophthalmic operations a year! From 1949 to 1952 Dr Szuniewicz carried out research work on the surgical treatment of corneal astigmatism. His interesting refractive procedures were done at Yale University in the USA and the techniques he developed arose from the work he had initially done in China from 1946 to 1948. Dr Suniewicz moved from the USA to Brazil in 1952 where he continued his refractive surgery research until 1954 and his missionary service until his death in 1963.

History, 20th Century↗

PubMed1989

Comparison of conventional fluorescein angiography film images with a cathode ray tube display.

We evaluated the effectiveness of cathode ray tube (CRT) displays in the transfer of diagnostic information to the ophthalmologist. Retinal fluorescein angiography images were used and data were taken using the receiver operating characteristic experimental paradigm. Three ophthalmologists with experience ranging from two to 12 years participated in the study. Sixty-eight images were selected from proof sheets of 800 original images. Next, these images were digitized, then each set was shown on its respective display (slide projection for the proof sheet images and CRT for the digital images). These 68 images were from a variety of patients and represented a broad range of normal and abnormal retinas (including diabetic retinopathy, hypertension independent of diabetes, and sickle-cell disease). Results show (1) that there is no difference between the systems in terms of diagnostic accuracy; (2) that certainty of diagnosis was not a function of the system; and (3) that although there was an effect due to experience of the ophthalmologist, it did not affect diagnosis accuracy. We conclude that CRT displays at conventional video resolutions can deliver the needed diagnostic information as well as film. We also hypothesize that digital enhancement techniques can increase the available diagnostic information beyond that of film.

Computer Systems↗

PubMed1989

Diabetic choroidal and iris vasculature scanning electron microscopy findings.

Scanning Electron Microscopy (SEM) was used to study vascular casts of twenty-four autopsy eyes taken from patients with long-standing insulin-dependent Diabetes Mellitus. These casts were compared to casts of ten 'normal' autopsy eyes from patients without a history of diabetes or other vascular disease. The SEM findings in the choroidal vessels of the diabetic eyes included: increased tortuosity, focal vascular dilations and narrowings, hypercellularity, vascular loops and microaneurysm formation, 'drop-out' of choriocapillaries, and sinus-like structure formation between choroidal lobules in the equatorial area. In the iris, neovascularization was evident in the vascular casts in cases with clinically recognized rubeosis iridis. These findings indicate that there is significant involvement of the uveal tract in diabetic eyes. The present study strongly supports the Hidayat and Fine light microscopic observation that the diabetic choroid demonstrates significant vascular changes (e.g. narrowed vessels with possible 'drop-out' of capillaries and neovascularization). Changes in the diabetic choroid, especially in the choriocapillaris, may be a contributing factor in diabetic retinopathy, resulting in decreased oxygenation of the outer layer of the retina. Short reviews and updated information of diabetic eye disease provide some additional insights into the vascular problems in the eye.

Adult↗

PubMed1989

Chorioretinal anastomoses in age-related macular degeneration.

Both eyes (obtained at autopsy) from a 79-year-old man with a history of age-related macular degeneration and glaucoma were studied. One eye was studied histologically using light microscopy and transmission electron microscopy. The other eye was prepared for scanning electron microscopy after injection of Batson's mixture into the ocular vasculature. Well-developed anastomoses between the retinal and choroidal circulation in the macular area and a pathologic tubular pattern of the choriocapillaris were found. This is an adaptation of the perifoveal circulation to changes in the fovea and a choroidal vascular response to damaged tissue.

Aged↗

PubMed1988

Scanning electron microscopy of human ocular vascular casts: the submacular choriocapillaris.

Vascular casts were prepared from ten human orbits removed at autopsy from patients with no previous history of vascular disease. The ages ranged from 7 months to 68 years. The time interval between death and injection of the orbit was always less than 12 h. The vascular casts were examined under scanning electron microscopy with particular attention to the submacular region. We present photomicrographs of common findings seen in each of our specimens, and discuss our results with respect to current models of the submacular angioarchitecture.

Adolescent↗

PubMed1988

Changes in the diabetic choroidal vasculature: scanning electron microscopy findings.

Scanning electron microscopy (SEM) was used to study vascular casts of 20 cadaver eyes according to our previously described technique. All eyes were taken from patients with long-standing diabetes mellitus type I. The SEM findings in the choroidal vessels included: increased tortuosity, dilation and narrowing, hypercellularity, vascular loop and microaneurysm formation, "drop-out" of choriocapillaries, and sinus-like structure formation between choroidal lobules. To our knowledge, these are the first SEM studies of the vascular casts performed on human cadaver eyes from diabetics.

Adult↗

PubMed1988