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Biomedical subjects

J A Kylstra

Publications and source records attributed to J A Kylstra.

At least 19 recordsLinked to original sources
PubMed1995

Clinical course and systemic correlates of retinopathy of prematurity in quintuplets.

PURPOSE/METHODS: We studied clinical correlates of retinopathy of prematurity in four surviving quintuplets with similar low birth weights and gestational age of 27 weeks. Prospective serial ophthalmoscopic examinations and retrospective chart analysis were used. RESULTS/CONCLUSIONS: Retinopathy of prematurity varied among the neonates from stage 2 with total regression to threshold progressing to retinal detachment. Severity of eye disease correlated with duration of mechanical ventilation and of parenteral nutrition, as well as frequency of hypoglycemia and of hypercapnia. Poor outcome correlated inversely with weight gain.

Adult↗
PubMed1995

Indirect ophthalmoscope perimetry in patients with retinal detachment or retinoschisis.

PURPOSE/METHODS: We evaluated visual field testing, using indirect ophthalmoscopy, in patients with retinal detachment or retinoschisis. While performing ophthalmoscopy, we projected a shadow onto the schisis or detachment by holding a scleral depressor on the observer's side of the condensing lens. A response was recorded as positive if the patient saw the shadow. RESULTS/CONCLUSION: In all 20 detachment eyes, compared to zero of 12 schisis eyes, the response was positive. Indirect ophthalmoscope perimetry can help distinguish retinoschisis from retinal detachment.

Humans↗
PubMed1995

A numeric index based on spatial frequency for the tortuosity of retinal vessels and its application to plus disease in retinopathy of prematurity.

BACKGROUND: In retinopathy of prematurity (ROP), tortuosity of vessels near the posterior pole of the fundus is an important clinical sign, yet clinicians have difficulty estimating how tortuous the vessels are. METHODS: The authors have devised an objective, numeric index of retinal blood vessel tortuosity that is especially sensitive to the structural changes in vessels that occur in ROP, but it is not particularly sensitive to non-ROP changes. Computer software is used to calculate the index from fundus images; the quality of these images is typical of photographs or video-cassette frames that the authors record in the premature nursery. RESULTS: The index reliably segregates tortuous vessels from nontortuous ones and separates eyes that reach ROP treatment threshold from eyes that do not. CONCLUSIONS: The index forms an objective measure of the ROP disease state. Its calculation requires only segments of vessels and thus, is potentially adaptable to imaging systems that automatically extract vessel portions from fundus images.

Fundus Oculi↗
PubMed1993

Clinical predictors of scleral rupture after blunt ocular trauma.

We conducted a two-part study to define better the clinical predictors of scleral rupture after blunt trauma. In part 1 we ascertained the prevalence of scleral rupture among a population of patients examined in an ophthalmic emergency room with severe blunt ocular trauma over a six-month period. Scleral rupture was diagnosed in ten of 283 patients (3.5%). In part 2 we compared the clinical findings in 29 patients with scleral rupture to those of 273 patients with no scleral rupture after blunt trauma. We noted that eyes with visual acuity of light perception or less, an intraocular pressure of 5 mm Hg or less, an abnormally deep or shallow anterior chamber, or a media opacity preventing a view of fundus details by indirect ophthalmoscopy, should be considered ruptured when severe intra- or periocular hemorrhage is present. This diagnostic algorithm had a sensitivity of 100.0% (98.7% to 100.0%), specificity of 98.5% (97.1% to 99.9%), and a positive predictive value of 71.4% (66.3% to 76.5%).

Algorithms↗
PubMed1993

Ocular and associated neuropathologic observations in suspected whiplash shaken infant syndrome. A retrospective study of 12 cases.

We examined the eyes of 12 infants who died with the clinical and pathologic diagnosis of the shaken baby syndrome. The ocular histopathologic findings and the neuropathologic findings were compared. Preretinal, intraretinal, and subretinal hemorrhages were observed; hemorrhages of the superficial retinal layers and subsensory retinal space predominated. Retinal hemorrhages were found in 12 cases, intracranial hemorrhage was found in 11 cases, and cerebral edema was found in 10 cases. The intraretinal and periretinal hemorrhages were most prevalent at the posterior pole. Five cases had retinal folds. There was a low incidence of optic disc edema and choroidal hemorrhage.

Brain Edema↗
PubMed1992

Isolated ocular cryptococcosis in an immunocompetent patient.

A 62-year-old woman without evidence of immunocompromise was evaluated for uveitis and a subretinal lesion in the right eye. Laboratory evaluation, including cerebrospinal fluid analysis, revealed no apparent cause. The diagnosis of subretinal cryptococcosis was established by transscleral needle biopsy of the subretinal mass. Treatment with intravenous amphotericin B and oral 5-flucytosine brought recovery of visual acuity to 20/30-1 and resolution of the inflammation. This patient demonstrates that ocular cryptococcal infection must be suspected, even in the absence of predisposing factors or systemic findings, and that subretinal fine-needle aspiration is an important diagnostic tool in this setting.

Amphotericin B↗
PubMed1991

Management of suspected ocular laceration or rupture.

The records of 95 consecutive patients with suspected ocular laceration or rupture managed by a single surgeon were reviewed. A total of 86 patients were found to have a laceration or rupture, of whom 79 were followed up, for an average of 6.4 months. In 32 eyes (40%) the final visual acuity was 20/40 or better, and in another 32 the final acuity was less than 5/200. Eyes with lacerations had a better visual outcome than those with rupture due to blunt trauma. Of the 26 eyes operated on for suspected blunt rupture 6 (23%) were found not to have a rupture. Ruptured eyes were more likely than nonruptured eyes to have abnormal anterior chamber depth, vision less than hand motion and hyphema.

Adolescent↗
PubMed1988

Intraocular pressure increase associated with epsilon-aminocaproic acid therapy for traumatic hyphema.

We treated five patients receiving epsilon-aminocaproic acid who demonstrated sudden and accelerated clot dissolution with accompanying increases in intraocular pressure 24 to 96 hours after discontinuing treatment. All of these patients required additional ocular hypotensive medications and one patient required anterior chamber washout for persistently increased intraocular pressure. These findings suggest that certain patients with hyphema may be at risk for significant intraocular pressure increases following cessation of epsilon-aminocaproic acid therapy.

Adolescent↗
PubMed1986

The relationship between retinal vessel tortuosity, diameter, and transmural pressure.

Increases in retinal vein tortuosity are thought to be caused by increases in vascular transmural pressure. We have attempted to determine the relationship between retinal vessel tortuosity, diameter, and transmural pressure by examining the effects of changes in transmural pressure on latex tubes with fixed ends. As the transmural pressure is raised, tube diameter increases, but tortuosity does not begin increasing until a critical pressure is reached. Above the critical pressure, tortuosity increases more rapidly than diameter. Our results support the above hypothesis and also suggest that at high transmural pressures, retinal vessel tortuosity is a more sensitive indicator than is the diameter of changes in retinal venous transmural pressure, but diameter is more sensitive than tortuosity at lower pressures.

Humans↗
PubMed1983

Retinopathy of prematurity: a new look at an old disease.

The neovascular changes of the retinopathy of prematurity can occur in premature infants in three settings: (1) when high levels of supplemental oxygen are administered, neovascularization usually commences shortly after cessation of oxygen therapy; (2) when supplemental oxygen is given for long periods of time, neovascularization can develop while the infant is still receiving oxygen; and (3) neovascularization can occur without exposure to any supplemental oxygen. We propose a model which can explain the occurrence of the retinopathy of prematurity in all these settings. Our model demonstrates that whenever the retinopathy of prematurity occurs, arterial oxygen levels are inappropriately high in relation to the stage of retinal vessel development, even in premature neonates not given supplemental oxygen. The inhibitory effect of these elevated oxygen tensions upon carbon dioxide removal is indicated as a possible cause of neovascularization by leading to tissue acidosis and vasodilatation.

Carbon Dioxide↗
PubMed1978

Steady-state gas exchange in normothermic, anesthetized, liquid-ventilated dogs.

Anesthetized, paralyzed, purebred beagle dogs were ventilated for 45 min (n = 5) and 60 min (n = 5) with oxygenated (PIO2 = 685 mmHg) FC-80 fluorocarbon liquid at 38 degrees C. The PaCO2 remained constant at approximately 43 mmHg during 60 min of liquid ventilation (mean tidal volume = 290 ml, mean respiratory frequency = 2.8 breaths/min). The end-tidal PCO2 was consistently higher than PaCO2 during liquid ventilation. Histological examination by light as well as scanning electron microscopy of the lungs of dogs killed 10, 30, or 180 days after liquid ventilation revealed no pathological changes except for a slight increase in the number of macrophages, especially around the alveolar ducts. It is concluded that a steady state of gas exchange at near normal arterial carbon dioxide partial pressures can be maintained in anesthetized, normothermic dogs ventilated with FC-80 at respiratory frequencies of approximately 3 breaths/min.

Anesthesia↗
PubMed1977

Investigations of black bronchoalveolar human lavage fluid.

The removal by bronchoalveolar lavage (two occasions) of 10(11) black macrophages containing crystals of aluminum silicate, large amounts of amorphous carbon, and oxidized lipids was followed by considerable improvement in gas exchange in a patient. Sixty-eight percent of these pulmonary macrophages were viable and normal, as judged by chemotatctic and phagocytic activity. Except for cigarettes, no source for the previously mentioned ingested foreign substances was found. These observations suggest that removal by lavage of nonviable macrophages laden with foreign bodies from distal portions of the lungs of pulmonary patients may be therapeutically useful.

Carbon↗
PubMed1976

A fluorocarbon emulsion with a high solubility for CO2.

A stable emulsion can be prepared by subjecting a mixture of 30% (by volume) FC-80 fluorocarbon; a 0.3-M THAM solution titrated to pH 7.4 with HCl; and 0.04 g F68 Pluronic surfactant per milliliter FC-80 to ultrasonic energy. The emulsion has a density of 1.24 g/ml; and absolute viscosity of 2.4 centipoise; and an approximate fluorocarbon-droplet diameter of 3mu. The approximate CO2 content of the emulsion at partial pressures ranging from 30 to 60 mm Hg is 132 ml (STPD)/liter + (5.5 X PCO2). The O2 content in ml (STPD)/liter equals 0.213 X PO2 (mm Hg).

Carbon Dioxide↗
PubMed1975

Volume-controlled lung lavage in a woman with cystic fibrosis.

A 22-year-old woman with cystic fibrosis was treated by volume-controlled lavage of each of her lungs on two occasions. Following the first lavages, the patient's vital capacity increased by 1.03 liters and her 1-sec forced expiratory volume increased by 0.70 liters/second. Similar improvements, although less pronounced, were noted after both lungs has been lavaged a second time. It is concluded that volume-controlled lung lavage can be of benefit as an adjunct in the treatment of patients with cystic fibrosis.

Adult↗