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Biomedical subjects

R R Pfister

Publications and source records attributed to R R Pfister.

At least 73 records · Page 4Linked to original sources
PubMed1980

Ascorbic acid in the treatment of alkali burns of the eye.

Severe ocular alkali burns in rabbits result in a decrease in aqueous humor ascorbate levels to one-third normal levels. If this deficiency is reversed by immediate treatment with parenteral or topical ascorbate, there is a significantly decreased incidence of subsequent corneal ulceration and perforation. The morphologic changes in these ulcerating corneas are typical of those noted in scorbutus (scurvy). It is concluded that alkali injury to the ciliary epithelial transport processes or ciliary body vasculature results in localized deficiency of ascorbic acid in the aqueous humor and cornea. The development of corneal ulceration is thought to be based on this deficiency which results in the failure of fibroblasts to produce sufficient collagen for repair. A randomized clinical trial of ascorbic acid in the treatment of human alkali burned eyes is now underway.

Alkalies↗
PubMed1980

The efficacy of ascorbate treatment after severe experimental alkali burns depends upon the route of administration.

Rabbit eyes were subjected to severe alkali burns (35 sec, 12 mm, 1N sodium hydroxide). In one experiment, rabbits in the treated group received a daily subcutaneous injection of neutralized ascorbic acid solution (0.5 gm/kg body weight), while control animals received no treatment. At the termination of the experiment (30 days), 11 of 16 eyes (68.8%) in the control group had ulcerated or formed descemetoceles, and in the experimental (treated) group, 15 of 20 eyes (75%) had ulcerated, formed descemetoceles, or perforated. In a second experiment, burned rabbits received topical 10% ascorbic acid while control eyes were given the vehicle only. At the termination of the experiment (34 days), 16 of 20 eyes (80%) in the control group had ulcerated or perforated, compared to five of 18 eyes (27.8%) in the ascorbate treated groups. The failure of systemic administration of ascorbic acid to prevent corneal ulceration could be explained on the basis of inadequate penetration of ascorbic acid into the anterior segment of severely burned rabbit eyes. On the other hand, immediate topical treatment of identically burned rabbit eyes achieved greatly elevated aqueous humor ascorbate levels and provided substantial protection from corneal ulceration and perforation.

Administration, Topical↗
PubMed1978

The corneal and conjunctival surface in vitamin A deficiency: a scanning electron microscopy study.

A model system of acute vitamin A deficiency in the guinea pig was used to investigate changes in corneal and conjunctival morphology. Hypovitaminosis A was induced by feeding experimental animals a purified gel diet deficient in vitamin A, while a control group received a vitamin A enriched diet. By the fifth week experimental animals exhibited a significant decrease in plasma vitamin A levels compared to controls. Animals were sacrificed at intervals from 5 to 9 weeks, and the corneas and conjunctivae were examined histologically and by scanning electron microscopy. Conjunctivae from control animals showed large numbers of goblet cells, whereas 16 of 18 experimental conjunctivae were completely devoid of goblet cells. Tarsal, palpebral, and cul-de-sac epithelia from deficient animals all showed many superficial squamous cells uplifted from the surface. Also, rugae were notably absent from the palpebral and cul-de-sac conjunctivae. The corneas of vitamin A--deficient animals exhibited varying degrees of superficial epithelial cell desquamation and keratinization. In addition, reduced numbers of microprojections and membrane breakdown were observed. These morphological and clinical findings are correlated with the possible role of vitamin A in cellular physiology.

Animals↗
PubMed1977

Supraclavicular node biopsy in testicular tumors.

Fifty-seven patients with germinal cell carcinoma of the testis were evaluated routinely, with the addition of a supraclavicular node biopsy as a final staging procedure. Five patients showed more extensive disease with the addition of this staging modality.

Biopsy↗
PubMed1977

Pelvic lymphadenectomy in stage A prostatic cancer.

Pelvic lymphadenectomy as a staging procedure in clinically apparent prostatic adenocarcinoma has long been recognized and its value appreciated. Twenty-three recent cases from the University of Colorado of clinically unapparent carcinoma of the prostate were studied with this modality, 5 Stage A1 and 18 Stage A2 tumors. Four of the 18 Stage A2 tumors but none of the A1 lesions after negative staging procedures revealed metastatic disease to the pelvic lymph nodes. Our experience indicated this modality should be employed in selected cases of incidental adenocarcinoma of the prostate.

Adenocarcinoma↗
PubMed1977

The normal and abnormal human corneal epithelial surface: a scanning electron microscope study.

The surface morphology of 108 corneal buttons obtained at keratoplasty showed specific patterns for each disease process. The surface over a traumatically scarred cornea was identical to that of undamaged sites, showing microvilli and microplicae in various numbers and combinations. Keratoconus specimens showed many dark cells, frequently noted to have surface blebs 0.25 to 3 micrometer in size over the entire cone in the nipple type, and in a broad basal band inside the cone or over the entire button in the sagging-cone type. Some blebs contained cytoplasm and 250 A glycogen-like granules. In larger, dark cells, holes were found in the blebs and the plasma membrane was degenerated. Corneal epithelial edema was manifested by a large irregular surface caused by the anterior bulge of edematous cells, many attached by only a small area, and variable-sized depressions, often the size of epithelial cells. More than a year after stromal scarring from herpetic keratitis, many epithelial cells lay loosely on the surface whereas other epithelial cells were edematous and partially detached from the surface cell sheet. Localized heaping of rounded epithelial and inflammatory cells persisted in some areas.

Cornea↗
PubMed1976

Endoscopy and the detection of genitourinary carcinoma.

Endoscopy in the detection of urinary tract cancer is one of the primary tools of the urologist. It is used in the localization of bleeding sites, the systematic follow-up in detecting recurrent malignancies, the pathologic staging of carcinoma of the bladder through transurethral biopsy, and the identification and biopsy of primary transitional cell carcinoma of the prostate. It is also a prime tool in the diagnosis of ureteral and pelvic tumors through retrograde pyelography, brush biopsy, and urine collection for cytology. Nephroscopy is now also possible for the obscure lesions difficult to diagnose otherwise. Urethroscopy is also important in detecting malignant changes. The various sites for urologic cancer, their incidence, and the role of endoscopy in relation to other means of diagnosis and management are discussed.

Age Factors↗
PubMed1976

The effects of ophthalmic drugs, vehicles, and preservatives on corneal epithelium: a scanning electron microscope study.

Scanning electron microscopy was found to be of considerable use in evaluating the effects of various commonly used drugs, vehicles, and preservatives on the corneal surface. Of the preparations tested 0.3 per cent gentamicin caused many central cellular microvilli to stand up prominently. Moderate losses of peripheral microvilli, with mild superficial cellular desquamation was noted with 0.25 per cent phospholine iodide, 2 per cent pilocarpine, 2 per cent fluorescein, and Fluor-I-Strip. The top layer of epithelial cells desquamated with 4 per cent cocaine or neopolycin treatment. The top two layers of cells were lost when 0.01 per cent benzalkonium chloride was instilled. When cell death occurred severe membrane disruption was accompanied by loss of microvilli and rupture of intercellular tight junctions. These studies show that the cytotoxicity of topical ocular preparations can be tested in an in vivo model and evaluated by scanning electron microscopy.

Anesthetics, Local↗
PubMed1976

Renal carbuncle: unusual cause of postpartum febrile morbidity.

Obstetricians should be alert for medical problems disguised as postpartum complications. A patient with renal carbuncle which presented as postoperative fever is described. The lesion was treated by percutaneous drainage. A brief summary of the differential diagnosis of renal abscess is presented.

Abscess↗
PubMed1976

Ascorbic acid prevents corneal ulceration and perforation following experimental alkali burns.

Depressed aqueous humor glucose and ascorbic acid levels returned to control values within 14 days following a 20 sec, 6 mm. diameter, 1N sodium hydroxide burn of the rabbit cornea. These corneas did not ulcerate or perforate. After a 20 sec., 12 mm. diameter, 1N sodium hydroxide burn, aqueous humor glucose levels returned to normal values, but ascorbic acid levels remained significantly depressed for up to 30 days. These corneas became markedly ulcerated in about 60 per cent of animals and frequently perforated. Following 12 mm. alkali burns, rabbits treated daily with 1.5 Gm. of subcutaneous ascorbic acid rarely developed corneal ulcerations and the corneas did not perforate. It is suggested that exogenous maintenance of adequate aqueous humor levels of ascorbic acid overcomes the relatively scorbutic state of the anterior segment induced by a 12 mm. alkali burn, thereby impairing the development of corneal ulceration and perforation. Elevated aqueous humor levels of ascorbic acid had no influence on corneal epithelial cell migration patterns following alkali burns.

Alkalies↗
PubMed1975

Aqueous humor pH changes after experimental alkali burns.

Following application of 2N sodium hydroxide, or 8.1N ammonium hydroxide to rabbit cornea, the aqueous humor pH reached a maximum of 10.2, 11.9, and 12 within six minutes following 20-, 50-, and 100-mu1 sodium hydroxide burns, respectively; after two hours the pH had fallen to 8.5, 10, and 10.5. The maximum rise following application of 100-mu1 of ammonium hydroxide was 10.8, declining to about 9 at two hours. The fall in pH following a 100-mu1 sodium hydroxide burn was not greatly influence by external lavage. However, the pH was significantly lowered (12 to 10) by paracentesis alone and further reduced by immediate or delayed intracameral administration of phosphate buffer. On the basis of these results moderately severe and severe alkali burns of the eye should be treated by paracentesis and if possible with anterior chamber reformation with a sterile solution.

Alkalies↗
PubMed1975

Bench surgery and renal autotransplantation in the pediatric patient.

A new operative procedure in renal surgery has evolved from the extensive recent experience in kidney transplantation. Bench surgery and autotransplantation have not been, as yet, fully exploited by surgeons caring for children. This approach to reconstruction of renal substance and renal vessels has as its greatest dividend conservation of kidney tissue. The operation has specific applicability for selected cases of: (1) renovascular hypertension; (2) congenital obstructive uropathy; (3) bilateral Wilms' tumor, and; (4) renal trauma in children.

Adult↗
PubMed1975

Development of ureteral stone basket.

A new ureteral stone basket is presented which has several advantages over any available: it can be autoclaved, is less than 4 French, and has six wires. Clinical evaluation is included.

Humans↗