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Biomedical subjects

R L Gross

Publications and source records attributed to R L Gross.

At least 19 recordsLinked to original sources
PubMed1992

Intraoperative application of 5-fluorouracil during trabeculectomy.

We report the preliminary results of the first 20 consecutive cases in which the antimetabolite 5-fluorouracil (5-FU) was applied directly beneath the conjunctival flap during trabeculectomy in high-risk patients. Seventeen were considered early successes, with 3-month postoperative intraocular pressures less than 21 mmHg, representing at least a 20% decrease from preoperative values. Successful blebs were pale, with conjunctival microcysts and without significant vascularization over the trabeculectomy site, similar to the appearance of blebs in eyes administered postoperative subconjunctival injections of 5-FU. There were no cases of corneal epithelial defects, and no eyes had lost more than one line of preoperative vision at the time of last follow up. Although the longer term efficacy of this method is unknown, these results suggest that it may represent a safe and effective alternative for administering 5-FU.

Adult↗
PubMed1990

Laser placement in noncontact Nd:YAG cyclophotocoagulation.

We treated 40 eyes of 40 patients by using noncontact transscleral Nd:YAG cyclophotocoagulation to determine whether treatment 1.5 or 3.0 mm posterior to the corneoscleral lumbus was preferable. Patients were randomly assigned to one of the treatment groups, and all other variables, including power, number, and distribution of laser applications, were kept constant. Six months postoperatively, those treated 1.5 mm posterior to the corneoscleral limbus had a lower intraocular pressure (P = .0047) than those treated 3.0 mm from the corneoscleral limbus. The 1.5-mm group also required fewer retreatment (P = .017) and had a slightly lower occurrence of visual acuity loss after this procedure. We believe it may be advantageous to locate the laser application approximately 1.5 mm posterior to the corneoscleral limbus, rather than further posteriorly, when performing noncontact transscleral Nd:YAG cyclophotocoagulation.

Aged↗
PubMed1990

Dendritic keratopathy associated with beta-blocker eyedrops.

Four patients with chronic open-angle glaucoma developed a dendriform corneal epithelial lesion. Two were associated with the use of topical betaxolol for 2 months and 6 weeks, and two were related to topical levobunolol. Resolution occurred within 2 weeks of discontinuation of the beta-blocker eyedrop. The distinctive pattern of dendritic epithelial keratopathy associated with these topical medications may be due to epithelial toxicity with subsequent regeneration.

Adrenergic alpha-Antagonists↗
PubMed1990

Effect of transscleral neodymium: YAG cyclophotocoagulation on intraocular lenses.

A neodymium: YAG laser operating in the thermal mode was used to irradiate isolated intraocular lenses (IOLs) and to perform transscleral cyclophotocoagulation on pseudophakic autopsy eyes to investigate the potential damage to IOL haptics such irradiation may cause. In the isolated IOLs, 70 mJ of energy deformed and partially melted both polymethylmethacrylate (PMMA) and polypropylene haptics. One of the capsular-fixated PC-IOL haptics in an autopsy eye partially melted when irradiated with the maximum energy level (8.8 J), with the aiming beam focused 1 mm posterior to the limbus and maximal posterior focus offset.

Humans↗
PubMed1989

Risk factors for the development of Tenon's capsule cysts after trabeculectomy.

Tenon's capsule cysts (TCCs) are a complication of glaucoma filtering surgery. They are frequently associated with substantial elevations in intraocular pressure (IOP) beginning 2 to 8 weeks postoperatively. To determine the incidence and possible risk factors for the development of TCCs, case records of all patients who received trabeculectomy over a 4-year period at the Wills Eye Hospital were reviewed. The incidence of TCCs was 28% in those who underwent trabeculectomy. Characteristics of patients after trabeculectomy in whom TCCs developed were compared with patients after trabeculectomy in whom TCCs did not develop. Both univariate and multivariate techniques were used to assess the association of characteristics associated with the development of TCCs. Factors associated with increased risk (P less than 0.05) were: history of prior TCCs, argon laser trabeculoplasty, male gender, and the use of preoperative sympathomimetics. The use of a compression shell was associated with decreased risk (P less than 0.05).

Adult↗
PubMed1988

Surgical therapy of chronic glaucoma in aphakia and pseudophakia.

Most glaucoma surgical procedures are less successful in aphakic or pseudophakic eyes. The authors reviewed 91 consecutive initial glaucoma procedures in aphakic patients from 1979 to 1986 to determine successful outcomes and complications. Success was defined as an intraocular pressure (IOP) of at least 30% below the preoperative value and less than 21 mmHg, less than 2 lines of Snellen acuity loss, and no further surgical intervention. At 9 months, success rates were: trabeculectomy, 4 of 15 patients; cyclodialysis, 3 of 20 patients; neodymium:YAG (Nd:YAG) cyclophotocoagulation, 1 of 8 patients; cyclocryotherapy, 9 of 22 patients; anterior chamber tube shunt (Schocket procedure), 3 of 6 patients; and argon laser trabeculoplasty, 2 of 20 patients. Severe complications included phthisis bulbi in 11% of cyclocryotherapy and severe visual loss in 20% with cyclodialysis and 14% with cyclocryotherapy. Results confirm the difficulty of surgical therapy in these patients.

Aged↗
PubMed1979

I. Depressed immunological function in zinc-deprived rats as measured by mitogen response of spleen, thymus, and peripheral blood.

The in vitro responses of splenic, thymic, and peripheral blood lymphocytes to two T-cell mitogens (phytohemagglutinin and concanavalin A) and one B-cell mitogen (pokeweed mitogen) were investigated in zinc-deprived and pair-fed control rats. The responses to phytohemagglutinin of splenic, thymic, and peripheral blood lymphocytes from zinc-deprived animals were depressed by at least 50% in comparison with those of controls, and the difference between the two groups was significant for each tissue (P = 0.05). The responses to concanavalin A of splenic and peripheral blood lymphocytes were suppressed in zinc-deprived animals, and splenic and thymic responses to pokeweed mitogen were depressed by about 50% in comparison with those of controls; these results were significant at the P = 0.05 level. This study is the first to evaluate the effects of diet-induced zinc deprivation on lymphocyte transformation and immune function in rats.

Animals↗
PubMed1979

II. In vitro restoration by levamisole of mitogen responsiveness in zinc-deprived rats.

The effect of levamisole on the in vitro responses of splenic and peripheral blood lymphocytes to phytohemagglutinin were investigated in zinc-deprived and pair-fed control rats. The in vitro response of lymphocytes from zinc-deprived rats was markedly impaired in comparison with that of controls. The addition of levamisole to cultures of zinc-deprived splenic lymphocytes significantly improved their response to phytohemagglutinin by 54%. The addition of levamisole to cultures of zinc-deprived peripheral blood lymphocytes significantly improved their response by 116.2%. The addition of levamisole to control lymphocyte culture had no effect. This study may be the first to evaluate the beneficial effect of an immunomodulating agent on immune function in a nutritionally deprived host.

Animals↗
PubMed1978

Inability of vitamin A deficiency to alter benzo(a)pyrene metabolism in Syrian hamsters.

Syrian golden hamsters were placed on a control or vitamin A-deficient diet. When their serum vitamin A content was significantly reduced, i.e., to less than 10% of controls, the hamsters were killed and lung aryl hydrocarbon hydroxylase activity and metabolism of benzo(a)pyrene were determined. The benzo(a)pyrene metabolite profile was similar with control and A-deficient systems, and only few quantitative differences were noted. Addition of beta-retinyl acetate to the in vitro incubations did not substantially affect benzo(a)pyrene metabolism.

Animals↗
PubMed1977

Naturally occurring toxic substances in foods.

Numerous chemical toxins, including normal components of natural foods, e.g., mycotoxins, and toxic chemicals as contaminants such as pesticides, fertilizers, food additives, and preservatives, which are potentially toxic to humans, are discussed. Potential toxicity, the hazard to man represented by most of these chemicals, may be low because the concentration in food may be low. The gap in our knowledge of long-term effects makes rational decisions as to allowable levels of these substances a major problem. On the other hand, nitrosamines and aflatoxins are toxins for which there exists a voluminous literature documentaing extreme biologic activity in experimental animals and indirect evidence for activity in man. Epidemiologic evidence has linked them to human cancers, and because of increasing evidence of long-term human exposure to these toxins either as inadvertent contaminants during food preparation or as the metabolites of mycotic infestation this possible hazard demands intensive investigation. An exhaustive review of data from epidemiologic surveys in various parts of the world, as well as from long-term laboratory studies, represents an impressive start in this direction.

Aflatoxins↗
PubMed1975

Abnormal spontaneous rosette formation and rosette inhibition in lung carcinoma.

Fifty-five children with CID and known ADA status were studies at a workshop held in Albany, New York. Erythrocyte ADA determinations were performed in 22 of the 55 patients, 13 of whom were ADA negative. The ADA defect appears to be transmitted as an autosomal recessive trait. Some patients with CID and ADA deficiency have characteristic radiologic abnormalities of the skeleton, which are not found in other illnesses. The thymus glands of all patients with CID and ADA deficiency who could be examined have evidence of thymic involution manifested by presence of Hassall's corpuscles and differentiated germinal epithelium; this is in contrast to "classic" thymus findings in CID with normal ADA. Adenosine deaminase probably plays an important, although as yet undefined, role in lymphocyte development and/or function. The deficiency of ADA in CID is the first enzyme defect observed in a deficiency disease of specific immunity.

Aged↗
PubMed1975

In vitro immunological studies on East African cancer patients. II. Increased sensitivity of blood lymphocytes from untreated Burkitt lymphoma patients to inhibition of spontaneous rosette formation.

Frozen aliquots of peripheral blood mononuclear cells from patients with Burkitt's lymphoma (BL) at various stages of the disease have been compared with samples from East African children who were healthy or who suffered from non-malinant disorders. Using the sheep-cell rosette test (which is believed to identify T-lymphocytes), we found a significant reduction in the proportion of rosette-forming cells (RFC) in the samples from untreated BL patients. After reduction of remission the difference between BL patients and controls was abolished. Rosette formation was more readily inhibited by anti-lymphocyte globulin (ALG) in samples from untreated BL patients than in controls. On induction of remission the rosette inhibition curve shifted towards the control values. The findings are compatible with the presence, in untreated BL, of a circulating factor which impairs the capacity of T-lymphocytes to form rosettes with sheep erythrocytes. It remains to be established whether the functional capacity of T-cells to protect the host against tumour proliferation is also impaired.

Africa, Eastern↗