Search PubMed⌕ Search

Biomedical subjects

N A Sher

Publications and source records attributed to N A Sher.

31 records · Page 2Linked to original sources
PubMed1976

Demonstration of macrophage chemotactic factors in the aqueous humor during experimental immunogenic uveitis in rabbits.

Factors in the queous humor capable of increasing the random migration and chemotaxis of monocytes were demonstrated during experimental uveitis in the rabbit. Injection of endotoxin-free human serum albumin into the vitreous produced a severe inflammation detectable after 7 days and maximal between 12 to 21 days. Aqueous humor was measured for chemotactic activity with a modified Boyden chamber, which permitted the use of volumes of less than 0.025 ml. Chematactic activity was measurable during the primary inflammation and remained elevated for a short period of time after clinical inflammation and anterior chamber cellular reaction had decreased. A severe reinduction uveitis could be initiated by the intravenous injection of human serum albumin after day 30. Chemotactic factors could be measured at high titers by 8 h after this intravenous challenge.

Animals↗
PubMed1976

Contrasting effects of BCG on spleen and lymph node antibody responses in nude and normal mice.

Subcutaneous footpad injection of BCG causes a marked augmentation of popliteal lymph node plaque-forming cell (PFC) responses to DNP-derivatized hemocyanin and to sheep red blood cells, both T-dependent antigens, but not to DNP-derivatized Ficoll, a T-independent antigen. This augmentative effect occurs in normal thymus-bearing heterozygous (nu/+) mice, but not in congenitally athymic nude mice (nu/nu). In contrast, intravenous injection of BCG causes a suppressed splenic PFC response to subsequently administered T-dependent or T-independent antigens in both nude and nu/+ mice. BCG's augmenting effect on the lymph node appears to be mediated by a T-helper cell. BCG's suppressive effect in the spleen is not attributable to T cells. The actual mechanism of the BCG-mediated suppressive splenic effect remains incompletely defined at present.

Animals↗
PubMed1976

The effect of Mycobacterium bovis (Bacillus Calmette-Guérin) on macrophage random migration, chemotaxis, and pinocytosis.

Macrophage random migration, chemotactic responsiveness, and pinocytosis were studied in the guinea pig after Bacillus Calmette-Guérin (BCG) administration. Oil-induced peritoneal exudate cells were evaluated for random migration and chemotaxis in modified Boyden chambers. Pinocytosis was measured by the in vitro uptake of colloidal 198Au. There was a parallel increase in random migration and chemotaxis after an i.p. dose of 1.0 X 10(7) COLONY-FORMING UNIts of BCG. This was seen as early as Day 4, sustained through Day 21, and absent by Day 44. A number of different strains and preparations of BCG vaccine exerted a similar augmentation of macrophage mobility. In parallel assays, aliquots of macrophages from BCG-treated animals showed increased pinocytosis, first noted at Day 14, peaking at Day 28, and no longer measurable at Day 44. These alterations in macrophage function following BCG administration may in part contribute to the antitumor effect of BCG adjuvant therapy.

Animals↗
PubMed1975

Response of congenitally athymic (nude) mice to infection with Mycobacterium bovis (strain BCG).

Mice homozygous for the mutation "nude" (nu/nu) are athymic and lack thymus-dependent lymphocytes. Heterozygote (nu/+) controls, which are phenotypically and immunologically normal, and (nu/nu) mice were infected with 1.0 times 10-6 colony-forming units of Phipps strain BCG. In the spleens of nu/+ mice, there was a progressive increase in number of BCG up to the second week, followed by a gradual decline. However, in the nu/nu mice, BCG growth was gradual and continuous until termination of the experiment at 5 weeks. In the lung, significant differences were not noted until after the second week, at which time the nude mice showed a rapid increase (of more than 2 log10) in the number of BCG. However, the number of BCG was not significantly greater in the livers of either group. Changes in the normal histology of the lung included a massive influx of monocytes during the first 2 weeks which peaked at day 21. In the lungs of the nu/+ mice by day 28, there was considerable granuloma formation consisting of monocytes and small lymphocytes. However, in the lungs of nu/nu animals, the granulomas were made up primarily of monocytes with a lack of small lymphocytes. Acid-fast stains confirmed the presence of large numbers of organisms in the macrophages of nu/nu mice, with gradual destruction of these phagocytic cells.

Animals↗
PubMed1975

Effects of BCG, Corynebacterium parvum, and methanol-extration residue in the reduction of mortality from Staphylococcus aureus and Candida albicans infections in immunosuppressed mice.

An immunosuppressed mouse model was devised to test the effects of immunopotentiators on the prevention of bacterial and fungal infections. The effects of BCG and Corynebacterium were tested against Staphylococcus aureus and Candida albicans infection. The effect of methanol-extraction residue (MER-BCG) was tested against S. aureus septicemia. CDF mice were given various doses of BCG, 1.0 mg of C. parvum, or 0.5 mg of MER intraperitoneally at varying intervals before injection of an intravenous bacterial challenge. Four days before challenge, 300 mg of cyclophosphamide per ml was given intraperitoneally. BCG (106 colony-forming units) reduced mortality due to S.aureus at pretreatment intervals of 3, 7, 14, and 28 days. Isonicotinic acid hydrazide treatment elimated the protective effect of the live BCG. C. parvum was as effective as BCG against S. aureus septicemia when given 3 days before infection, but lost most of its protective effect after that time. MER protected at doses as small as 0.25 mg when given 25 days prior to challenge. Both BCG and C. parvum exerted a protective effect against Candida albicans infection.

Animals↗
PubMed1973

Virulence of six strains of Mycobacterium bovis (BCG) in mice.

The abilities of six strains of Mycobacterium bovis strain BCG to replicate in vivo and to cause spleen enlargement in the CDF(1) male mouse were compared. The strains were grown in synthetic medium and harvested soon after complete pellicles were produced on liquid medium. In addition, two freeze-dried commercially available preparations were tested. The comparisons were made on the basis of injecting equal numbers of colony-forming units. Strain differences were marked. The Brazil strain was most effective in stimulating spleen enlargement, and the Japan strain was the least effective. This correlated with the number of colony-forming units isolated from the spleen.

Animals↗
PubMedDate not supplied

The effect of various methods of eye immobilization on corneal topography.

BACKGROUND: Accurate, predictable, and safe refractive surgery requires immobilization of the eye. We measured the effects of current eye fixation techniques on human cadaver eyes. MATERIALS AND METHODS: Central to our study was a device specially designed to secure cadaver eyes and stabilize intraocular pressure. Topographical measurements were made with a modified Model 2 Corneal Analysis System (EyeSys Technologies, Houston, Tex) mounted vertically to allow analysis of a cadaver eye mounted in the artificial orbit. The effect on human cadaver eyes of six fixation instruments was assessed: forceps, U-shaped fixation forceps, a full Hofman-Thornton ring, a VISX vacuum fixation ring, a Meditec suction ring, and a new instrument, the Eye Fixation Speculum. RESULTS: The circular vacuum fixation rings caused minimal distortion, resulting in less than 1.00 diopter (D) of change. Forceps and U-shaped fixation forceps, which apply force at one or two points, caused significantly more distortion. Single-point fixation forceps distorted the cornea at the point of application a mean of +5.50 +/- 3.50 D, and, at 180 degrees from the point of instrument application, a mean of +2.00 +/- 1.90 D. U-shaped forceps apply force at two points, 90 degrees and 270 degrees, from the axis of instrument application. At these axes, the cornea was distorted a mean of +9.40 +/- 3.70 D and +8.30 +/- 3.10 D, respectively. CONCLUSIONS: Single- and multi-point fixation instruments, due to an asymmetric application of fixation force, significantly distort the cornea. Ring fixation instruments, which apply a more equally distributed force, cause less distortion.

Cornea↗
PubMedDate not supplied

Myopic excimer laser keratectomy: a preliminary report.

Six patients underwent excimer laser refractive keratectomy for the correction of myopia. All eyes, with the exception of patient 6, who underwent a previous failed epikeratophakia procedure and subsequent removal of the lenticule, had normal baseline ophthalmologic evaluations and best corrected visual acuities of 20/25 or better. Spherical equivalents ranged between -5.50 and -12.00 diopters. Under topical and peribulbar anesthesia, the central corneal epithelium was removed. The delivery system of the laser was programmed to ablate corrections onto the central 5.0 mm of the cornea that would result in approximate emetropia. Moderate fluctuation of refractive and topographic parameters was noted during the period of epithelial healing and remodeling. At the 12th postoperative week, five of the corneas were clear on biomicroscopic evaluation with best corrected acuities of 20/20. The final patient, who was noncompliant in the use of topical corticosteroid therapy, developed a central, 2-mm opacity and resulting best corrected acuity of 20/40. Overall, the group demonstrated that myopic excimer laser photorefractive keratectomy is consistent with good wound healing, insignificant corneal scarring, a stable refractive correction, and excellent visual acuity.

Adrenal Cortex Hormones↗
PubMedDate not supplied

Topical diclofenac in the treatment of ocular pain after excimer photorefractive keratectomy.

BACKGROUND: Following excimer laser photorefractive keratectomy, patients experience significant ocular pain until corneal reepithelialization. Despite the use of cold compresses, bandage soft contact lenses, cycloplegics, narcotics, and topical corticosteroids, the pain has not been adequately controlled in many patients. METHODS: A randomized, double-masked, parallel-group study of diclofenac sodium 0.1% ophthalmic solution and its placebo vehicle was evaluated. Patients undergoing excimer myopic photorefractive keratectomy on their second eye were admitted overnight. Postoperative procedures included two drops of diclofenac or placebo immediately after surgery and then qid until reepithelialization, topical tobramycin (qid), 0.1% fluorometholone (q2h), cycloplegics, and a disposable soft contact lens. Thirty-two patients (diclofenac = 16, placebo = 16) were evaluated from +30 minutes to +96 hours by several types of questionnaires. RESULTS: Most patients who received placebo experienced pain, starting within 1 hour, peaking at 4 to 6 hours and lasting 36 to 48 hours. The diclofenac-treated patients rarely experienced the early peak in pain, had less pain overall until 72 hours postoperatively, and experienced significantly less photophobia and burning/stinging. Significantly fewer patients on diclofenac required oral narcotics. Three patients (diclofenac = 2, placebo = 1) developed corneal infiltrates, the etiology of which is not known. In a separate study we conducted, there was no difference in epithelial healing times between the diclofenac-treated eyes and those not receiving the drug. CONCLUSIONS: Diclofenac appears to significantly reduce the ocular pain following excimer photorefractive keratectomy.

Administration, Topical↗