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Biomedical subjects

N A Syed

Publications and source records attributed to N A Syed.

26 records · Page 2Linked to original sources
PubMed1997

Retinoblastoma in a dog.

OBJECTIVE: To describe and classify a retinal tumor found in a dog that histologically resembles human retinoblastoma and to discuss the molecular mechanisms of retinal oncogenesis. METHODS: A dog eye with a retinal tumor was examined histologically. Studies including immunocytochemical analysis for retinal S-antigen and glial fibrillary acidic protein, enzyme histochemical analysis for carbonic anhydrase, and nick-end DNA labeling were used to characterize the tumor. Normal retina from another dog and other tumors from dogs, including 2 ciliary body medulloepitheliomas and a brain medulloepithelioma, were examined as controls. RESULTS: The retinal tumor disclosed characteristics typical of human retinoblastoma, including Flexner-Wintersteiner rosettes. It showed strong immunoreactivity with S-antigen and glial fibrillary acidic protein. Carbonic anhydrase activity also could be shown in the tumor. Apoptosis was found to be the predominant method of cell death as shown by nick-end DNA labeling. In contrast to the other tumors examined, this tumor contained areas with retinal photoreceptor and glial differentiation. CONCLUSIONS: The histopathologic findings and differential staining characteristics in this retinal tumor are compatible with retinoblastoma, making this, to our knowledge, the first documented case of spontaneous retinoblastoma in an animal.

Animals↗
PubMed1997

The herpes simplex virus type 1 ribonucleotide reductase is required for acute retinal disease.

We have used a herpes simplex virus type 1 (HSV-1) ribonucleotide reductase (RR) null mutant (ICP6 delta) to determine if the HSV-1 RR is required for acute retinal disease. Injection of the ICP6 delta mutant into the vitreous induced mild transient signs of infection (vitreal infiltrate, retinal inflammation, and changes in retinal cytology). In contrast, the parental KOS and a revertant virus (ICP6 delta + 3.1) in which the RR gene had been restored, caused severe retinitis. Injection of media alone also induced mild transient signs of disease. Two months after infection, ICP6 delta injected eyes could not be distinguished from normal eyes. Repeated injection of ICP6 delta (3 times, 2 weeks apart) resulted in vitreal infiltrate near the site of injection but the retina did not appear damaged. The mutant, ICP6 delta, grew to peak titers 1 x 10(3) to 1 x 10(5)-fold lower and cleared faster than KOS or ICP6 delta + 3.1 in the injected eyes suggesting that the reduced virulence was due to reduced ability of the virus to grow. These results show that the viral RR is required for acute retinal disease.

Acute Disease↗
PubMed1997

Refractory giant cell arteritis with spinal cord infarction.

We report an elderly patient with aggressive steroid-refractory giant cell arteritis manifesting as myelopathy and bilateral visual loss while on treatment. Pathologically, spinal cord infarction was observed and was due to extensive necrotizing granulomatous arteritis of spinal arteries. Spinal cord damage in giant cell arteritis is rare. One prior autopsy report of spinal cord infarction in giant cell arteritis did not identify vasculitic changes in the spinal arteries.

Aged↗
PubMed1996

Melanocytes and iris color. Light microscopic findings.

OBJECTIVE: To systematically evaluate morphologic differences in iris stroma that contribute to clinically perceptible differences in iris color, using immunohistochemical identification of stromal melanocytes and fluorescence microscopy. METHODS: Paraffin-embedded sections from 51 human irides were stained with S100a and fluorescein isothiocyanate. Cells were counted and scored as melanocytes or other. Melanocyte number, proportion, and density were determined for light-colored (blue), medium-colored (hazel) and dark-colored (brown) irides and compared. RESULTS: No statistically significant difference was observed for mean total cellularity or mean melanocyte number among the three color groups. Mean total stromal cell count was 1177 +/- 259 (mean +/- SEM), and mean melanocyte number was 778 +/- 196 per 5-micrometer section. In human irides, 65.9% of the iris stroma is composed of melanocytes. Melanocyte density (number of cells per square millimeter) is not related to iris color. CONCLUSION: The number of melanocytes, the proportion of melanocytes, and iris stromal cellularity are not major contributors to iris color.

Aged↗
PubMed1992

Infectious conjunctivitis.

This article is designed to aid the clinician in the diagnosis of bacterial and viral conjunctivitis by evaluating a wide variety of infectious causes of conjunctivitis. The work-up, including techniques of examination and pertinent laboratory studies, is discussed. Clinical features of each type are covered at length and specific therapy for each is included.

AIDS-Related Opportunistic Infections↗
PubMed1989

Radical hysterectomy and tailored postoperative radiation therapy in the management of bulky stage 1B cervical cancer.

Ninety-two patients with Stage IB cervical cancers having a diameter equal to or greater than 4.0 cm were treated with radical surgery. Thirty-two patients received postoperative radiotherapy because of operative findings suggestive of high risk of pelvic recurrence. All 32 irradiated patients were treated with a standard pelvic field. Four patients also received paraaortic radiotherapy, and ten received intravaginal brachytherapy. Postoperative complications were seen in five patients (two nonirradiated, three irradiated). Projected 5-year survival is 79% (71% 5-year survival in irradiated patients, and 83% 5-year survival in nonirradiated patients). Preoperative evaluation of tumor volume was not found to reliably predict histologic high risk factors such as depth of stromal invasion, risk of lymph node metastases, or presence of extracervical/uterine involvement. A primary surgical approach in this group of patients with large-diameter Stage IB cervical cancers allows definition of those patients who might benefit from a combined surgical and radiotherapeutic approach to treatment based on findings at operation.

Adenocarcinoma↗
PubMed1988

Treatment of advanced and recurrent squamous carcinoma of the uterine cervix with constant intraarterial infusion of cisplatin.

Twelve patients with primary or locally recurrent squamous carcinoma of the cervix were treated with constant internal iliac artery infusion of cisplatin (CDDP) via a totally implantable chemotherapy pump. Seven previously untreated patients received standard external and interstitial radiotherapy (RT) in conjunction with CDDP infusion. Five patients with isolated pelvic recurrences received CDDP therapy only. The chemotherapy pump was refilled weekly on an outpatient basis. All nine evaluable patients developed unilateral or bilateral lower extremity pain which responded to dosage reduction. No renal or marrow toxicity was seen. Both of the evaluable patients treated for recurrent tumor died 32 and 60 weeks after initiation of treatment. The seven patients treated primarily with RT + CDDP infusion include one who expired with persistent tumor and one with no evidence of disease (NED) after exenteration for a pelvic recurrence at 48 and 85 weeks respectively. The five remaining patients are NED at 12 to 60 weeks. Constant internal iliac artery infusion of CDDP via an implantable chemotherapy pump can be performed with acceptable toxicity. The preliminary results suggest that further study in previously untreated undergoing concurrent radiotherapy is warranted.

Carcinoma, Squamous Cell↗