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Biomedical subjects

L S Evans

Publications and source records attributed to L S Evans.

At least 19 recordsLinked to original sources
PubMed1995

The effect of prostaglandin E1 on liver adenine nucleotides and cytoplasmic enzymes in a porcine model of normothermic hepatic ischemia.

The liver has been judged relatively resistant to ischemia, but prolonged inflow occlusion at normothermic conditions can produce evidence of reversible or irreversible hepatocellular damage. Cytoprotective agents have been used both experimentally and clinically to afford extended viability of hepatocytes under reduced perfusion. One agent, prostaglandin E1, has been described clinically as effective in sustaining liver function under ischemic conditions. We have sought to verify this observation in an experimental model using prolonged normothermic inflow occlusion. Twenty miniature pigs were anesthetized and subjected to subtotal normothermic hepatic inflow occlusion (portal vein, hepatic artery, choledochal vessels) to allow for sufficient splanchnic decompression. Half of the animals received pretreatment with prostaglandin E1 (alprostadil) 500 micrograms intravenously. Inflow occlusion was maintained for 2 hours followed by reperfusion and killing 24 hours later. As a measure of functional preservation, the tissue adenine nucleotides adenosine monophosphate, diphosphate, and triphosphate (AMP, ADP, ATP) were measured in ischemic liver by freeze-clamping and high-performance liquid chromatography during occlusion and after reperfusion. Cytosolic enzyme determinations (aspartate transaminase, alanine transaminase, lactate dehydrogenase) were also made before occlusion and after reperfusion. As a possible indicator of cellular injury, blood ionized Ca++ was measured before inflow occlusion and after reperfusion. Although no difference was found in levels of AMP and ADP between prostaglandin E1 and control animals, ATP levels rose significantly higher during recovery in prostaglandin E1 animals at 60 minutes and 24 hours after reperfusion (13.97 +/- 1.29 and 13.60 +/- 0.91 mumoles/gm dry weight prostaglandin E1 vs. 9.25 +/- 0.97 and 9.80 +/- 0.85 mumoles/gm dry weight co control, P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1993

Depth of anisometropic amblyopia and difference in refraction.

Disagreement exists as to whether the depth of anisometropic amblyopia correlates with the degree of anisometropia. We reviewed the charts of 303 consecutive patients with the diagnosis of amblyopia. Thirty-five patients with untreated anisometropia without strabismus were identified. The best-corrected visual acuities, manifest refractions, and autorefractions were recorded. The differences in spherical equivalent, root mean square, and an index of anisometropia, which we defined, were calculated. The depth of amblyopia was strongly correlated to all three measures of anisometropia for both hyperopic and myopic individuals. Our new index of anisometropia was an excellent predictor of the depth of amblyopia.

Adolescent↗
PubMed1993

Comparison of three methods of estimating the parameters of the Naka-Rushton equation.

The Naka-Rushton equation empirically describes the amplitude R of the dark-adapted electroretinogram b-wave, as a function of stimulus luminance L, as R/Rmax = Ln/(Ln + Kn). Estimating the three parameters Rmax, n, and K of this function from electroretinogram data is of both experimental and clinical interest. Several different approaches have been developed to accomplish this analysis, but these approaches may derive different estimates of the three parameters. To examine this possibility, we compared the results of three methods of fitting the Naka-Rushton equation to data sets obtained from 30 normal subjects. Two methods were nonlinear curve-fitting programs; the third method involved fitting a regression line to transformed data. The results indicate that solutions provided by these methods have consistent differences, which may be an important consideration when comparing results reported in studies that used different curve-fitting methods.

Dark Adaptation↗
PubMed1992

The occurrence and management of esophageal fistulas resulting from Hodgkin's disease.

At their radiation therapy (RT) department, the authors saw a young woman with an esophageal fistula from Hodgkin's disease that was not responsive to chemotherapy; this prompted a review of the literature concerning such patients. Twenty-two patients with Hodgkin's disease and esophageal fistula were found to have been reported previously. Most patients had active disease at the fistula site, and most who were treated with RT or chemotherapy had prompt fistula closure. Fistula formation as a complication of RT for Hodgkin's disease was found to be an extremely unusual occurrence.

Adult↗
PubMed1991

Increased intraocular pressure in severely burned patients.

Six eyes of three patients with severe body burns had intraocular pressure ranging from 37.2 to 81.7 mm Hg. Because of extreme orbital congestion, lateral canthotomies were performed, which caused abrupt decrease in intraocular pressure (range, 17.6 to 49.0 mm Hg). None of the patients had a history of glaucoma, narrow angles, or any precondition for a pupillary block mechanism. Two patients survived and neither had optic nerve damage or increased intraocular pressure after hospital discharge. Tonometry should be performed in patients with severe burns and orbital congestion, especially in those patients receiving large amounts of intravenous fluids. Lateral canthotomies may be of benefit to relieve potentially damaging high intraocular pressure.

Adult↗
PubMed1991

Effects of topical suprofen and flurbiprofen on the miosis produced by anterior chamber irrigation with cholinergic agonists.

Pretreatment with topical nonsteroidal anti-inflammatory drugs is common practice to maintain maximal pupil dilation for cataract surgery. Most surgeons also inject a cholinergic agent intracamerally for miosis after intraocular lens insertion. We evaluated the effects of topical suprofen and flurbiprofen on the miosis induced by anterior chamber irrigation with either acetylcholine or carbachol. One eye of 30 pigmented rabbits was dilated with cyclopentolate HCl and phenylephrine HCl. Three groups, each composed of ten eyes, received flurbiprofen, suprofen, or a control. In each group, five eyes received acetylcholine by anterior chamber irrigation and five received carbachol. Pupil diameters were measured with calipers before and five minutes after irrigation by an observer unaware of the treatment regimen. Irides irrigated with carbachol constricted less than those irrigated with acetylcholine (P = .016). In anterior chambers irrigated with carbachol, suprofen was associated with less miosis than either tears (P = .005) or flurbiprofen (P = .009); however, if the infusion was performed with acetylcholine, no differences between the three groups were noted (P = .44).

Acetylcholine↗
PubMed1988

Concomitant 5-fluorouracil, mitomycin-C, and radiotherapy for advanced gynecologic malignancies.

Advanced gynecologic neoplasms continue to pose major therapeutic problems; 22,500 deaths were estimated for 1987. Between December 1983 and October 1985, there were 25 patients evaluated at our institution who on joint evaluation by the radiation oncologist and gynecologic oncologists were found to have extensive disease not amenable to standard therapy. Patients were to be treated by a combined modality approach with Mitomycin-C and 5-Fluorouracil given concomitantly with radiotherapy. Nineteen patients were treated definitively and six patients were treated with palliative intent (24 primary, 1 recurrent). The patients ranged in age from 27 to 90 years with a mean of 57.3 and a median of 57. Primary sites at presentation were: cervix--14 patients, vagina--7 patients, and vulva--4 patients. The initial FIGO stages at time of the initial diagnosis were: Stage I--1 (recurrent), Stage II--4, Stage III--15, and Stage IV--5. Chemotherapy consisted of 5-fluorouracil 1 gm/m2 given continuous infusion for 4 days with Mitomycin-C 10 mg/m2 IV push on day 1. Radiation therapy was started on day 1. Only 2 of 25 patients (8%) required chemotherapy reductions. All 25 patients received mega-voltage irradiation. The external beam dose range was 2000-6500 cGy and 14/25 patients received intracavitary or interstitial therapy. In the definitive patient group, there was no reduction in the therapeutic dose. Only four patients underwent surgical therapy. With a minimum follow-up of 8 months and a median follow-up of 28 months, the survival for the entire population was 56%. Fourteen of the 19 patients (74%) treated definitively are surviving with 12 patients having no evidence of disease. Survival by site in the definitive therapy group was cervix--70%, vulva--100%, and vagina--66%. The overall response rate was 84% at 3 and 9 months (3 months; CR--36%, PR--48%, and 9 months; CR--60%, PR--24%). There were no local recurrences in the 12 patients who achieved a complete response. Three patients died of metastatic disease alone and the overall local control was 60%. Evaluation of therapeutic side effects was performed. Hematologic analysis by the Southeastern Oncology Group criteria showed neutropenia in 14 patients (1--life-threatening, 2--severe, and 11 patients--mild/moderate) and thrombocytopenia was observed in 11 patients (all mild or moderate). All hematologic complications resolved. Acute complications did not appear increased except for the addition of mild oral mucositis (12 patients). Six patients demonstrated late effects with only 2 patients felt to have severe complications.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

Socioeconomic aspects of hepatic transplantation.

The outcome, cost, length of hospital stay, and extent of rehabilitation were assessed in a series of 55 consecutive patients who received hepatic transplants between May 1982 and June 1985. In the same geographic region, medical costs for patients dying of hepatic failure without transplantation were studied for years 1979 through 1984. One-yr survival in all patients transplanted without cancer was 71%, and the mean cost was $92,866. The mean cost of hospitalization for the last 12 months of life in patients who did not receive transplants was $45,643. Eight-two percent of patients surviving the first yr are fully rehabilitated and restored to pre-illness activity. Length of hospital stay, hospital costs, and the extent of rehabilitation closely correlate with a grading system based on preoperative medical status. We conclude that hepatic transplantation restores high-quality, useful life to patients with endstage liver disease in a predictable and cost-effective manner.

Adolescent↗
PubMed1986

Acidosis as a presenting feature of chloramphenicol toxicity.

Metabolic acidosis has previously been described in the gray baby syndrome, but has not been documented as a presenting feature. Four seriously ill children (bronchiolitis, hypoaldosteronism, dysautonomia, Reye syndrome), ages 4 months to 11 years, received chloramphenicol (CAP) intravenously. After initial stabilization, unexplained metabolic acidosis occurred 40 to 81 hours after beginning CAP. Serum CAP concentrations were 84, 62, 80, and 30 micrograms/ml, respectively, when acidosis was recognized. Hypotension, hypothermia, and abdominal distension occurred a mean of 23 hours after the onset of acidosis. Acidosis resolved and signs of the gray baby syndrome cleared with the decrease in serum CAP concentrations. Metabolic acidosis should be considered an early sign of CAP toxicity, and CAP should be used in reduced doses in severely ill patients, especially those with liver dysfunction.

Acidosis↗
PubMed1986

Inappropriate antidiuretic hormone secretion after cataract extraction under local anesthesia.

We report a case of a patient who underwent bilateral cataract extractions under local anesthesia. In both operations, the patient developed signs, symptoms, and laboratory data consistent with the syndrome of inappropriate secretion of antidiuretic hormone. In this era of outpatient cataract surgery, we believe this diagnosis should be entertained postoperatively in the proper clinical setting.

Aged↗
PubMed1985

Hereditary macular dystrophies in relation to radionuclide ocular scintigraphy.

Radionuclide ocular scintigraphy was investigated to determine whether it could detect blood-retinal barrier disruption secondary to retinal disease. Patients were examined who had hereditary macular dystrophies and good correlations were found of the dynamic and equilibrium results obtained on scintigraphy with the clinical disease state. This test may hold promise as another measurement of the disruption of ocular physiology in retinal diseases.

Humans↗
PubMed1984

Oculomotor nuclear complex infarction. Clinical and radiological correlation.

We describe a patient with an isolated mesencephalic dorsal tegmental infarct affecting the oculomotor nuclear complex and medial longitudinal fasciculus, documented by high-resolution computed tomography, after undergoing percutaneous transluminal coronary artery angioplasty. Clinically, the patient exhibited bilateral ptosis, bilateral internuclear ophthalmoplegia, transient convergence retractory nystagmus, and minimal somnolence. We believe the combined clinical and radiological findings favor the presence of a caudal, dorsal, and paramedian embolic infarct in the territory of the paramedian branches of the mesencephalic artery as the most likely mechanism for these exceptional findings and correlate them with Warwick's scheme of the oculomotor subnuclei.

Cerebral Infarction↗
PubMed1983

The use of radionuclide retinal scintigraphy for the assessment of retinopathy in diabetes mellitus.

A computerized radiotracer technique for the detection of loss of retinal vascular integrity secondary to diabetes is presented. Radionuclide retinal scintigraphy with Technetium-99m DTPA was performed on 40 insulin-dependent diabetics and 10 nondiabetics. A ratio of eye to brain activity was used to eliminate errors associated with absolute counting. Ratios were found to be significantly higher in diabetics, especially those with active neovascularization. This technique may prove useful in the assessment and staging of eyes prone to retinopathy.

Adult↗