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Biomedical subjects

R L Anderson

Publications and source records attributed to R L Anderson.

At least 235 records · Page 13Linked to original sources
PubMed1988

Full-thickness unipedicle flap for lower eyelid reconstruction.

We developed a technique for lower eyelid reconstruction using a full-thickness unipedicle flap from the upper tarsal portion of the upper eyelid. The lost tissue is replaced with identical tissue from the ipsilateral upper eyelid. The technique is best suited to shallow defects of the temporal lower eyelid. The levator aponeurosis and Müller's muscle are recessed to avoid upper eyelid retraction. The key to performing this operation is a thorough knowledge of eyelid anatomy and preservation of its microvascular supply. This procedure has produced satisfactory to excellent results in 17 patients and offers the reconstructive surgeon several advantages over other techniques.

Eyelid Neoplasms↗
PubMed1988

Results of optic nerve sheath fenestration for pseudotumor cerebri. The lateral orbitotomy approach.

Twenty-eight patients with pseudotumor cerebri underwent 40 optic nerve sheath fenestrations for relief of visual loss or to preserve vision. Twenty women and eight men underwent 16 unilateral fenestrations and 12 bilateral operations. Papilledema disappeared or was strikingly reduced in 24 of 28 patients. The other four patients had gliotic discs (two patients) or were followed up for only a short time. Visual acuity improved in 12 of 40 eyes and remained the same in 22 of 40 eyes. Seventeen eyes had preoperative visual acuity of 20/30 or better. In six eyes visual acuity decreased. Of eight eyes operated on that had visual acuity of 20/200 or worse, only three showed improvement. Visual fields improved in 21 of 40 eyes and remained the same in ten eyes. Five of the ten eyes that did not change had poor vision before surgery. Eight eyes in five patients continued to lose acuity postoperatively. Each of these eight eyes had a concomitant loss of visual field. An additional two eyes developed visual field loss with preserved visual acuity. The indications for surgery are early evidence of progressive loss of visual field or acuity in a patient with pseudotumor cerebri. Severe vision loss presents little opportunity for improvement but fenestration may be used in a last effort to preserve or restore vision.

Adult↗
PubMed1988

Optic nerve sheath fenestration in pseudotumor cerebri. A lateral orbitotomy approach.

In patients with pseudotumor cerebri accompanied by loss of vision, optic nerve sheath fenestration is an effective route to prompt recovery of vision. A lateral orbitotomy approach to decompression of the optic nerve is appropriate for the ophthalmologist with adequate orbital experience. A rectangular window of dura and arachnoid, measuring approximately 3 X 5 mm, is excised from the bulbous portion of the optic nerve. It is important that the arachnoid within the window is excised because an intact arachnoid is an effective barrier to cerebrospinal fluid egress. The use of operating microscope, microsurgical instrument, and microdissecting techniques are emphasized. Twenty-eight patients (40 eyes) with progressive visual loss were treated by surgical nerve sheath fenestration. A study of the indications, results, and complications of this procedure is presented in a companion article.

Arachnoid↗
PubMed1988

Pressure, biochemical, and culture characteristics of CSF associated with the in utero drainage of various fetal CNS defects.

An attempt has been made to begin delineation of the in utero dynamics of fetal intracranial fluid in the presence of brain malformations. In a series of patients with fetal CNS defects, cephalocentesis was performed at the time of therapeutic abortion or to facilitate vaginal delivery. Intracranial CSF pressures and volumes were quite variable. There did not appear to be any discernible correlation between the type of lesion and the intracranial pressure. Fetal CSF glucose levels were moderately depressed and protein concentrations were very high. Neither virus nor bacteria were cultured from fetal CSF or amniotic fluid of any patients in this series.

Amniotic Fluid↗
PubMed1988

The effect of various saccharin forms on gastro-intestinal tract, urine and bladder of male rats.

Sodium saccharin, potassium saccharin, calcium saccharin and the free acid when fed to young male rats at a level of about 200 mumol/g diet all produced an equivalent increase in the caecal enlargement indicating that this phenomenon was due to the saccharin ion and not the accompanying cation. The sodium and potassium salts caused greater polydipsia and polyuria than the calcium or free acid forms. Simple hyperplasia of the bladder was noted in the rats ingesting the sodium and potassium salts but not in those ingesting the calcium or free acid forms. The difference in urine and bladder response to the salt forms is not attributable to the difference in the total urinary saccharin or the urinary concentration of saccharin. These results suggest that excess water absorption from the lower bowel and the concomitant bladder responses are dependent upon monovalent cation absorption but independent of saccharin absorption.

Animals↗
PubMed1988

Ethylenediaminetetra(methylenephosphonic acid): genotoxicity, biodistribution, and subchronic and chronic toxicity in rats.

Ethylenediaminetetra(methylenephosphonic acid), EDITEMPA, was tested for oral toxicity in rats in a 13-wk feeding study (at doses of 0, 5, 50 and 500 mg/kg/day) and in a chronic feeding study (at doses of 0, 4, 20 and 100 mg/kg/day). EDITEMPA was also tested for genotoxicity in the Ames, mouse lymphoma, unscheduled DNA synthesis, and in vivo cytogenetics assays. Additionally, absorption, distribution and excretion (ADE) studies were conducted following administration of [14C]EDITEMPA to rats by gavage and via the feed and drinking-water. The principal finding in the 13-wk study was mild anaemia in male and female rats given 500 mg/kg/day, which was resolved during a 9-wk recovery period. In the chronic study, there was no substantial evidence of any treatment-related toxicity or carcinogenicity. Differences in survival of control and treated females (noted late in the study) were interpreted to represent unusually good survival in controls; however, a compound-related increase in mortality could not be completely ruled out. Tests for genotoxicity were all negative. ADE studies revealed that [14C]EDITEMPA was poorly absorbed from the gastro-intestinal tract and that most of the absorbed dose was rapidly excreted by the kidneys or sequestered in bone. The gavage route of administration led to four- to six-fold increases in bone EDITEMPA levels as compared with administration in the feed and drinking-water, respectively. These results suggest that no significant toxicity or carcinogenicity concerns arise from EDITEMPA when it is administered in the feed at the concentrations tested. Reversible anaemia was seen only at very high doses and was interpreted as being secondary to EDITEMPA's ability to interfere with iron absorption and utilization. Localization of EDITEMPA in bone indicated a high degree of affinity for mineralizing tissues, consistent with its chelating properties. There was, however, no effect on bone resorption or mineralization. A comparison of human drinking-water levels of 3500 ppm EDITEMPA (based on a no-effect level of 100 mg/kg/day in rats) with the estimated worst-case exposure in humans of 0.01 ppm suggested a safety margin greater than 1 x 10(5).

Administration, Oral↗
PubMed1988

An hypothesis of the mechanism of urinary bladder tumorigenesis in rat ingesting sodium saccharin.

An hypothesis is presented of a mechanism for the sodium saccharin (NaS)-associated tumorigenesis of the urinary bladder that occurs in male rats. The ingestion of high doses of NaS is associated with increased urine volume and bladder mass. In rats with an inherently high urine output, the diuresis associated with NaS ingestion combined with the increasing diuresis that occurs with age in male rats results in a chronic demand for a bladder-volume increase that is met by excessive cell division of the bladder epithelium. This enhanced mitosis in the bladder epithelium can result in a significant incidence of bladder tumours. Male rats exposed to NaS during early life show an exacerbation of tumour incidence, and it is proposed that this is because the exacerbation of the effects of NaS on the gastro-intestinal and urinary tracts results in increased urine output and bladder hyperplasia in these rats.

Animals↗
PubMed1988

Thermotolerance and heat shock protein induction by slow rates of heating.

The magnitude of thermotolerance and the level of heat shock protein (HSP) expression have been measured in Chinese hamster ovary cells after gradual temperature transients from 37 degrees or 39 degrees to 42 degrees or 43 degrees C. When the level of thermotolerance was measured by clonogenic survival after challenging temperatures between 42 degrees and 43 degrees, substantial thermotolerance was observed. However, when the challenging temperature was raised to 45 degrees C, proportionally less thermotolerance was apparent. Heat shock proteins were quantitated by scanning densitometry of radiographs and, in the case of HSP 70, by immunoassay. Scanning densitometry revealed that low levels of heat shock proteins were synthesized during the heating gradients, but less than after a heat shock at 45 degrees C that delivered an equivalent heat dose. The immunoassay of HSP 70 levels measures both pre-existing and newly synthesized protein, and showed that there was net increase in HSP 70 during two of the heating gradients tested, despite the increase in synthesis noted on the gels. Higher turnover of HSP 70 at the elevated temperatures possibly accounted for the failure to detect a net gain in total protein. In contrast, the total amount of HSP 70 doubled during the 6 hr following a heat shock of 45 degrees for 10 min, an equivalent heat dose to one of the gradients where no net increase in HSP 70 was measured by immunoassay. It appears, then, that tolerance to hyperthemia at 43 degrees C or below may occur under some conditions in the absence of elevated levels of HSP 70, but tolerance to higher temperatures is more closely correlated with increased levels of heat shock proteins. However, even at higher temperatures, our data show disparities between the levels of HSP measured and the thermotolerance expressed.

Animals↗
PubMed1988

Early experience with open fetal surgery for congenital hydronephrosis.

The fetus with severe bilateral hydronephrosis and associated oligohydramnios in the second trimester is doomed at birth by ongoing pulmonary and renal damage. Since decompression with percutaneously placed catheters anesthetic, surgical, and tocolytic techniques for open fetal anesthetic, surgical, and tocolytic techniques for open fetal urinary tract decompression in animals, and have now applied those techniques to a small group of five patients. One had bilateral ureterostomies and the subsequent four had marsupialization of the bladder. All pregnancies proceeded to cesarean delivery at 32 to 35 weeks' gestation. There was no long-term maternal morbidity, and two mothers have since experienced normal pregnancies. Three fetuses had return of normal amniotic fluid dynamics, and all three had adequate pulmonary function at birth, suggesting that fatal pulmonary hypoplasia associated with early severe oligohydramnios had been reversed. Two neonates died at birth with pulmonary hypoplasia. One had no amniotic fluid even after decompression, and the other had some amniotic fluid after decompression but a tiny chest cavity due to the long period of severe oligohydramnios before decompression. Of the three surviving infants, one had normal renal function when she died of unrelated causes at 9 months of age. One has normal renal function at 23 months and the third had failing renal function at 2 1/2 years and has grown and developed normally, but will require renal transplantation. We have now developed selection criteria that would exclude from treatment the two fetuses who died of pulmonary hypoplasia and the one who developed renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Hemangioblastoma of the optic nerve. Report of a case and review of literature.

The authors present a case of an optic nerve hemangioblastoma in a young woman with von Hippel-Lindau disease. The initial diagnosis was made by incisional biopsy. Tumor growth led to progressive proptosis and loss of light perception. Excision was carried out by lateral orbitotomy. Clinically and radiographically, the tumor resembled an optic nerve meningioma or glioma. Review of the other known cases offers no information as to the potential spread of this benign tumor from the intraorbital optic nerve to the optic canal. Optic nerve hemangioblastoma must be considered in the differential diagnosis of optic nerve tumors in patients with or without von Hippel-Lindau disease.

Adolescent↗
PubMed1988

Orbital emphysema: a potentially blinding complication following orbital fractures.

A case of visual loss due to orbital emphysema secondary to a blow-out fracture of the orbit is presented. Because vision returned to 20/20 following an optic nerve decompression procedure, we hypothesize that our patient developed a compressive optic neuropathy with ischemia due to the emphysema. Essential instructions concerning the injury that the emergency physician should give the patient suffering an orbital blow-out are also presented.

Adolescent↗
PubMed1988

DNA damage does not appear to be a trigger for thermotolerance in mammalian cells.

The hypothesis that DNA damage is the trigger for thermotolerance in mammalian cells was tested in Chinese hamster ovary cells by looking for evidence of thermotolerance after ionizing radiation or ultraviolet light exposure. As previous studies have demonstrated that relatively non-toxic radiation exposures do not induce thermotolerance in mammalian cells (Li et al. 1976), higher doses, comparable to those used in yeast to induce thermotolerance (Mitchel and Morrison 1984), were tested in this study. Doses of this magnitude are lethal to mammalian cells, thereby precluding the use of clonogenic survival as an endpoint. We therefore used three alternative assays which are indicators of the subsequent development of thermotolerance. These were; (a) heat-induced inhibition of total protein synthesis, (b) heat-induced uptake of dansyl lysine, and (c) synthesis of heat shock proteins. Only total protein synthesis revealed evidence of a small degree of thermotolerance which occurred immediately after ionizing radiation exposure. By 4 h postirradiation the tolerance, as measured by this assay, was no longer evident. No evidence of thermotolerance was seen following UV exposure. In addition, when a large radiation dose was given either immediately before or after a heat treatment used to induce thermotolerance, there was no alteration in the level of heat-induced tolerance, despite the extensive number of DNA stand breaks caused by the radiation. Our data therefore suggest that, in mammalian cells, the type of DNA damage caused by ionizing radiation is not the trigger for the induction of thermotolerance.

Acclimatization↗
PubMed1988

Membrane lipids of B16 melanoma cells and heat-resistant variants.

Membrane lipid composition and fluidity of a series of B16 melanoma cell variants with increased resistance to heat were analysed for changes within the lipid component that may contribute to the acquisition of heat resistance. Within one series of heat-resistant lines the cholesterol content of the cells decreased as their heat resistance increased. The most heat-resistant line, WH75, had 40 per cent less cholesterol than the parent line. No change in the composition of phospholipid fatty acids was found. An increased level of membrane fluidity in WH75 was demonstrated by electron paramagnetic resonance using 5- or 12-doxyl stearic acid. When challenged by heat the increase in membrane fluidity was similar for WH75 and for the parent line. Thus the increased heat resistance of the variants is probably not due to their ability to adapt to heat challenge by increasing membrane thermostability. The inverse relationship between heat resistance and cholesterol content was not demonstrated in two other series of heat-resistant variants. The cholesterol decrease, therefore, is not a universal response of cells as they acquire heat resistance.

Acclimatization↗
PubMed1988

CO2 laser treatment of eyelid syringomas.

Syringomas are benign epithelial tumors of the sweat glands. The diffuse nature of these raised tumors makes surgical treatment difficult. Three patients with eyelid syringomas were successfully treated with CO2 laser vaporization. CO2 laser therapy appears to be a safe and effective mode of treatment for these benign superficial eyelid tumors.

Adenoma↗
PubMed1988

Comparison of nurse and computer recording of ICP in head injured patients.

The importance of intracranial pressure monitoring in management and study of the head-injured patient is clearly recognized by the clinician responsible for intensive care. However, in many institutions studies requiring quantitative measures of ICP in head-injured patients are limited by lack of sophisticated computer monitoring equipment. In this study we tested the ability of the nurse to describe ICP course by manual record and compared these results with an on-line computerized ICP monitoring system. The nurse recorded a single "end-hour" value of ICP from the bedside monitor while the computer averaged 720 data samples of ICP during the hour. Our results obtained from five head-injured patients undergoing ICP monitoring showed 55% of the 347 data points had a difference in ICP of 0.01 to 3.0 mm Hg and 38% differed between 3.01 and 6 mm Hg. In comparison, 84% of nurse observations were within 6 mm Hg. Comparison of the temporal course of nurse and computer ICP values combined with the frequency distribution of error data indicates the nurse "end-hour" value is a reasonable estimate of the patient's mean ICP for the entire hour as measured by the computer. Nurses can now ask questions regarding various aspects of a patient's ICP course and compare data with other groups as long as the method of data collection is defined in the same manner.

Computers↗