Biomedical subjects

S Kaleta

Publications and source records attributed to S Kaleta.

3 recordsLinked to original sources

PubMed1990

31P magnetic resonance spectroscopy of animal uveal melanoma.

Scleral surface coils were used to obtain in vivo magnetic resonance spectra (MRS) of Greene melanoma implanted in the rabbit uvea. Well-localized tumor spectra (4.7 Tesla) with good signal-to-noise ratios (S/N) were obtained from the tumor with a "single-pulse" sequence in less than 1 hour. Tumor localization was confirmed with one-dimensional spectroscopic imaging studies. Serial 31P spectra were obtained during tumor growth and after both optimal and suboptimal hyperthermia. Early 31P MRS change is correlated with tumor treatment response and preceded histologic evidence of cell destruction. Twenty-four to 48 hours after successful treatment, the inorganic phosphate/nucleoside triphosphate (NTP), and phosphomonoester/NTP ratios were significantly increased from 1.2 +/- 0.1 to 1.7 +/- 0.1 and 1.3 +/- 0.1 to 1.8 +/- 0.2, respectively. In contrast, untreated or ineffectively treated tumors showed little change. Interpretation of 31P MRS data in this animal uveal melanoma model after the first week was complicated by decreased S/N, increased contamination from contiguous tissues, ingrowth of fibroblasts, macrophages, and intratumor hemorrhage.

Animals↗

PubMed1989

Bromodeoxyuridine uptake in the assessment of hyperthermic therapy for intraocular tumor.

Assessment of uveal melanoma response after many nonenucleation therapies is difficult with current modalities, since tumor regression is usually delayed. The goal of most treatments, including ionizing radiation or radiation and adjunct hyperthermia, is to destroy the reproductive capacity of the tumor. Cell cycling analysis with bromodeoxyuridine, a thymidine analogue only incorporated during DNA synthesis, was a useful indication of tumor control after hyperthermia was used to treat a Greene intraocular melanoma model. Cell cycling decreased from a mean of 16% before therapy to less than 1% in all the successfully treated tumors. Cell cycling changes preceded histologic evidence of cell death. In contrast, tumors that grew after insufficient treatment had increased cell cycling to a mean of 25%. Cell cycling studies with bromodeoxyuridine represent a sensitive gauge of the reproductive integrity of the tumor.

Animals↗

PubMed1988

Activated T lymphocytes in uveitis.

Two colour flow cytometry techniques were used to assess the activation stages of peripheral and intraocular T lymphocytes in uveitis. Increased numbers of T lymphocytes bearing the interleukin-2 (IL-2) receptors were found in intraocular fluids or peripheral blood or both of 35/51 patients with uveitis. This increased expression of IL-2 receptors on lymphocytes correlated with increased expression of other early T lymphocyte activation markers, HLA-DR and L-35. Both T helper cells (Leu-3A+) and suppressor cells (Leu 2A+) were activated in vivo. A positive correlation was seen between lymphocyte activation and clinical uveitis activity. In idiopathic uveitis activation of Leu-3A lymphocytes (helper/inducer) was significantly increased, and intraocular activation of the Leu-2A lymphocytes (cytotoxic/suppressor) was significantly decreased. These data show that some patients with idiopathic uveitis have a perturbation of T helper cells. Twenty-two of 31 patients with idiopathic uveitis, not associated with systemic disease, had increased peripheral T lymphocyte activation. This finding indicates that in some inflammations believed to be restricted to the eye an abnormal systemic immune activation exists.

Antigens, Differentiation, T-Lymphocyte↗