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Biomedical subjects

M D Farber

Publications and source records attributed to M D Farber.

32 records · Page 2Linked to original sources
PubMed1989

Neodymium:YAG laser cutting of intraocular lens haptics in vitro and in vivo.

Various complications following intraocular lens (IOL) surgery result in explantation of the lenses. Haptic fibrosis may necessitate cutting the IOL haptics prior to removal. In this study we used the neodymium: YAG (Nd:YAG) laser to cut polypropylene and poly(methyl methacrylate) (PMMA) haptics in vitro and in rabbit eyes. In vitro we were able to cut 100% of both haptic types successfully (28 PMMA and 30 polypropylene haptics). In rabbit eyes we were able to cut 50% of the PMMA haptics and 43% of the polypropylene haptics. Poly(methyl methacrylate) haptics were easier to cut in vitro and in vivo than polypropylene haptics, requiring fewer shots for transection. Complications of Nd:YAG laser use frequently interfered with haptic transections in rabbit eyes. Haptic transection may be more easily accomplished in human eyes.

Animals↗
PubMed1988

X-linked retinitis pigmentosa. Profile of clinical findings.

An evaluation of 56 patients with X-linked retinitis pigmentosa revealed a profile of findings that include the following: night blindness within the first two decades of life; spherical refractive errors of -2.00 diopters or greater in addition to an increased prevalence of a cylindrical correction of +1.50 diopters or greater; appreciable impairment of central visual acuity to 20/200 or less by the fifth decade of life; characteristic patterns of field loss; presence of a foveal lesion in up to 75% of the study group; posterior subcapsular lens opacities; and nondetectable electroretinographic amplitudes in more than two thirds of the patients (using conventional full-field recording procedures). These observations are of general value in diagnosis of this disease and for counseling of patients afflicted with this severe form of hereditary night blindness.

Actuarial Analysis↗
PubMed1985

Autosomal dominantly inherited retinitis pigmentosa. Visual acuity loss by subtype.

Sixty-eight patients with autosomal dominant retinitis pigmentosa were divided into two distinct subtypes and studied for visual function using a life-table analysis. Type 1 patients (n = 23) had diffuse pigmentation, concentric visual field loss, and no recordable electroretinogram. Type 2 patients (n = 45) as a group had regionalized pigmentation, sectorial field loss, and some recordable electroretinogram. The cumulative probability of maintaining a visual acuity of 6/12 (20/40) or better over each decade of life decreased rapidly in eyes of type 1 patients; for type 2 eyes, this probability remained above 90% through the fifth decade of life. The presence of an atrophic-appearing foveal lesion was associated with a reduction in visual acuity to 6/15 (20/50) or worse in a majority of patients. Data from this study indicate that investigators should look for subtypes within the major genetic groupings of retinitis pigmentosa for more accurate assessment of a patient's potential for maintaining good central visual acuity.

Adolescent↗
PubMed1985

Treatment of low vision in fundus flavimaculatus.

Twenty-eight patients with fundus flavimaculatus were evaluated retrospectively after they had undergone examination for and treatment of low vision. Despite poor distance acuity, 27 (96%) of the patients could read 1M (20/50 reduced Snellen) or smaller print with a spectacle lens, and all patients could read standard-sized print (1M text) with some optical aid. Because such uniform improvement is uncommon among patients with low vision, we recommend examination for and trial of low-vision aids for those patients with this disorder who are having visual difficulties.

Adolescent↗
PubMed1985

Cooperative Study of Sickle Cell Disease: Demographic and socioeconomic characteristics of patients and families with sickle cell disease.

Socioeconomic data on 3538 black patients enrolled in the Cooperative Study of Sickle Cell Disease (CSSCD) from 1979 to 1981 are summarized and compared with the U.S. black population (USBP) where appropriate. The following contrasts between the patients and families with Sickle Cell Disease (SCD) and the USBP were found: family structure differed, with fewer two-parent families (40 vs 54%) and more single female heads-of-household (53 vs 42%) within the SCD population; of those employed, twice as many of the SCD patients of both sexes worked in white collar positions; a higher percentage of patients were unemployed and disabled; and male SCD patients had a lower median personal income than USBP males. Several similarities were also noted: the percentage of high school graduates was 71% for SCD patients and 75% for the USBP; female heads-of-household employed full time earned approximately the same salary as USBP females. These data will help health professionals who counsel SCD patients and their families.

Adolescent↗
PubMed1985

A case-control inquiry into the etiology of hairy cell leukemia.

A case-control study was conducted to investigate the etiology of hairy cell leukemia. Forty-five individuals with histologically confirmed hairy cell leukemia comprised the cases. Three neighborhood controls were selected on the basis of age (+/- 5 years), race, sex, and residence at the time of the interview for each case. There was no association found for cigarette smoking, alcohol or coffee consumption and hairy cell leukemia. With respect to occupational risk factors, employment in woodworking or in farming was of borderline significance. Reported exposure to organic chemicals in the workplace was significantly greater among both sexes of the cases than among their respective matched controls (relative risk (RR) = 3.10). Other variables found to be significantly associated with hairy cell leukemia were farm birthplace (RR = 4.20), anemia (RR = 4.29), migraine (RR = 4.80), infectious mononucleosis (RR = 9.00), and routine use of aspirin (RR = 3.41) or tranquilizers (RR = 4.50). No association between radiation and hairy cell leukemia was detected.

Alcohol Drinking↗
PubMed1984

A randomized clinical trial of feeder vessel photocoagulation of proliferative sickle cell retinopathy. II. Update and analysis of risk factors.

Follow-up of patients enrolled in a randomized prospective trial of feeder vessel photocoagulation for proliferative sickle cell retinopathy has shown that photocoagulation is effective in preventing vitreous hemorrhage and visual loss from vitreous hemorrhage. In addition, a reduction of visual loss from all causes in photocoagulated eyes approaches statistical significance. Analysis of control eyes shows that there are three independent risk factors for the occurrence of vitreous hemorrhage: (1) the presence of the SC genotype, (2) the presence of vitreous blood at the initial evaluation and, (3) the presence of greater than 60 degrees of perfused neovascularization.

Anemia, Sickle Cell↗
PubMedDate not supplied

Adenylyl cyclase and G-proteins in Phytomonas.

Phytomonas sp. membranes have an adenylyl cyclase activity which is greater in the presence of Mn2+ than with Mg2+. The Mg2+ and Mn2+ activity ratio varies from one membrane preparation to another, suggesting that the adenylyl cyclase has a variable activation state. A[35S]GTP-gamma-S-binding activity with a Kd of 171 nM was detected in Phytomonas membranes. Incubation of these membranes with activated cholera or pertussis toxin and [adenylate 23P]NAD+ led to incorporation of radioactivity into bands of about 40-44 kDa. Crude membranes were electrophoresed on SDS-polyacrylamide gels and analyzed, by Western blotting, with the 9188 anti-alpha[s] antibody and the AS/7 antibody (anti-alpha[i], anti-alpha[i1], and anti-alpha[i2]. These procedures resulted in the identification of polypeptides of approximately 40-44 kDa. Phytomonas adenylyl cyclase could be activated by treatment of membrane preparations with cholera toxin, in the presence of NAD+, while similar treatment with pertussis toxin did not affect this enzyme activity. These studies indicate that in Phytomonas, adenylyl cyclase activity is coupled to an unknown receptor entity through G alpha[s] proteins.

Adenosine Diphosphate↗