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Biomedical subjects

R Schroeder

Publications and source records attributed to R Schroeder.

99 records · Page 6Linked to original sources

Clinical relevance of low levels of preformed alloantibodies detected by flow cytometry in the first year post-kidney transplantation.

OBJECTIVE: To determine the prevalence of transplants performed with a false-negative cytotoxicity cross-match and to analyze the clinical relevance of alloantibodies (Ab) detected only by flow cytometry (flow). METHODS: We studied 66 patients undergoing kidney transplantation from a cadaveric donor. All patients had a simultaneous negative T+AHG+DTT and B+DTT. Pretransplant sera were retrospectively analyzed by flow cytometry according to an Emory University protocol: (1) T+ and B-: Ab anti-class I; (2) T- and B+: anti-class II; (3) T+B+: anti-class I + II. Chi-square, Fisher exact, Student t test, and Kaplan Meier analyses were employed with significance assigned at P < or = .05. RESULTS: The overall incidence of false-negative cytotoxicity was 33.3% (22/66), namely, 6.1% (n = 4) anti-class I; 9.1% (n = 6) anti-class II; and 18.2% (n = 12) anti-class I + II. Primary nonfunctioning grafts occurred in 6.8% (3/44) and 13.6% (3/22) negative and positive flow patients (two anti-class I + II and one class II; P = .39). The incidence of graft loss in the first year was respectively, 13.6% (6/44) and 18.2% (4/22; two anti-class II and two anti-class I + II; P = .72). Compared to flow-negative grafts, creatinine levels were significantly higher among flow-positive patients at 8 and 12 weeks. One-year graft survivals were 86.4% among negative versus 81.8% for the positive group (P = .67). CONCLUSIONS: We observed that 33% of kidney transplant recipients had low levels of alloantibodies detected only by flow. This single factor was associated with the worst graft function in the first trimester with a suggestion of a higher risk for non-functioning graft.

Cadaver↗

Developmental toxicity evaluation of unleaded gasoline vapor in the rat.

To evaluate the potential of unleaded gasoline vapor for developmental toxicity, a sample was prepared by slowly heating API 94-02 (1990 industry average gasoline) and condensing the vapor. The composition of this vapor condensate, which comprises 10.4% by volume of the starting gasoline, is representative of real-world exposure to gasoline vapor encountered at service stations and other occupational settings and consists primarily of volatile short chain (C4-C6) aliphatic hydrocarbons (i.e. paraffins) with small amounts of cycloparaffins and aromatic hydrocarbons. A preliminary study in rats and mice resulted in no developmental toxicity in either species. However, a slight reduction in maternal body weight gain in rats led to the selection of rats for this guideline study. Groups of pregnant rats (n = 24/group) were exposed to unleaded gasoline vapor at concentrations of 0, 1000, 3000, or 9000 (75% lower explosive limit) ppm equivalent to 0, 2653, 7960, or 23,900 mg/m3, for 6 h/day on gestation days 6-19. All rats were sacrificed on gestation day 20. No maternal toxicity was observed. Developmentally, there were no differences between treated and control groups in malformations, total variations, resorptions, fetal body weight, or viability. The maternal and developmental NOAEL is 9000 ppm. Under conditions of this study, unleaded gasoline vapors did not produce evidence of developmental toxicity.

Administration, Inhalation↗

Prenatal oral (gavage) developmental toxicity study of decabromodiphenyl oxide in rats.

Decabromodiphenyl oxide (DBDPO) is a highly effective flame retardant that is primarily used in electrical and electronic equipment with a secondary, but important, application in upholstery textiles. DBDPO, the second largest volume brominated flame retardant in use today, has undergone a wide range of toxicology tests in mammalian species with the results indicating a no-adverse-effect level of approximately 1000 mg/kg/day in oral repeated-dose studies. An oral prenatal developmental toxicity study of the commercial DBDPO product (97% purity) was performed under current EPA OPPTS and OECD guidelines. Female Sprague-Dawley rats (25 mated females/group) received 0,100, 300 or 1000 mg DBPDO/kg/ day via gavage in corn oil during gestation days 0 through 19. All females survived until scheduled sacrifice. No clinical signs of toxicity were observed. Pregnancy rates in the control and treated groups ranged from 96% to 100% and provided 23 or more litters in each group for evaluation on gestation day 20. No effect of treatment was seen in maternal gestational parameters (body weight, body weight gain, and food consumption), uterine implantation data, liver weight, or necropsy findings. Likewise, no effect of treatment was seen in fetal body weights, fetal sex distribution, or during the fetal external, visceral, or skeletal examinations. The NOEL (no-observable-effect level) for maternal and developmental toxicity was 1000 mg DBPDO/kg/day, the highest dose level administered on gestation days 0 to 19.

Abnormalities, Drug-Induced↗

Primary myeloblastoma of the pineal region.

The first case of a pinealis region tumor of the hematopoietic system without known leukemia (so-called primary myeloblastoma, primary granulocytic sarcoma) is reported. Two weeks after resection, the 3.5-year-old patient suffered from a local recurrence. At this time, a bone marrow infiltration by leukemic blasts was diagnosed for the first time. An aggressive chemotherapy and radiation induced a complete remission, over a 26-month follow-up period. We examined the removed tumor tissue by routine histology methods, immuno- and enzyme histochemistry and electron microscopy. The CSF was studied by conventional microscopy and enzyme cytochemistry. We discuss the epidemiological data of nine previously published cases of primary intracranial myeloblastoma.

Brain Neoplasms↗

Renal lesions in subacute encephalomyelopathy (Leigh's disease).

A case of subacute necrotizing encephalomyelopathy (SNE; Leigh's disease) in an infant aged 19 months is reported. In addition to the typical central nervous lesions, hyperlactatemia and hyperpyruvatemia and morphological changes in the kidney were documented and have been identified as a tubulo-interstitial disease with a focal sclerosing glomerulopathy.

Brain Diseases, Metabolic↗