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Biomedical subjects

T Robinson

Publications and source records attributed to T Robinson.

At least 91 records · Page 5Linked to original sources
PubMed1985

Juvenile xanthogranuloma of the testis.

A 7-month-old boy presented with numerous xanthomatous skin lesions and a hard irregular swelling of the right testis. Clinically, the testicular lesion was impossible to distinguish from a malignant neoplasm. Histological examination of a skin biopsy and of the testis following orchiectomy showed lesions typical of juvenile xanthogranuloma.

Humans↗
PubMed1983

Complement-activating immune deposits in systemic lupus erythematosus skin.

Immune deposits at the cutaneous basement membrane zone are a characteristic feature of systemic lupus erythematosus. Previous studies using immunofluorescent methods to detect complement components have provided evidence that some deposits contain immune complexes capable of activating complement. However, this important biologic property of complexes has not been detected or measured using functional assays, and it has not been determined whether immune deposits can activate complement at the basement membrane zone. In this study immune deposits in biopsies of lupus skin have been examined using direct immunofluorescence for the third component of complement (C3) to detect complement deposited in vivo. In addition, the deposits have been studied using the leukocyte attachment assay and indirect C3 binding immunofluorescence to detect and measure complement activation at the basement membrane zone in vitro. The results show that complement activation occurs at the basement membrane in some but not all lupus skin containing immunoglobulin deposits, that deposits differ quantitatively in their ability to activate complement, and that direct C3 immunofluorescence is a relatively insensitive method for detecting complement-activating complexes. The results provide functional evidence suggesting that immune deposits in some lupus skin are complement-activating complexes and potentially capable of activating complement at the basement membrane in vivo. Furthermore, the results suggest functional assays for evaluating complement-activating complexes may be valuable supplements to immunofluorescence in exploring the relationship between immune deposits and systemic and cutaneous disease.

Basement Membrane↗
PubMed1982

Effect of cross-bridge kinetics on apparent Ca2+ sensitivity.

Three different ways of shifting the pCa/tension curve on the pCa axis have been studied and related to changes in the rate constants of the cross-bridge cycle. The curve midpoint shifts to higher pCa's when the substrate (Mg-ATP) is reduced from 5 to 0.25 mM, when the phosphate concentration is reduced from 7.5 mM to 0, and when the ionic strength is reduced from 0.200 to 0.120. The Hill coefficients of the pCa/tension curve in our standard saline (5 mM substrate, 5 mM free ATP, 7.5 mM phosphate, ionic strength 0.200, 15 degree C) are between 5.1 and 5.6 and fall to 3.0 with the left shift of the curve brought about by reducing both substrate and phosphate. Left shifts of the curve produced by reduction in the ionic strength do not result ina lower Hill coefficient. Reducing eigher substrate or phosphate is associated with a reduction in the optimal frequency for oscillatory work, but reduction in ionic strength is not so associated. Maximum tension increases with the left shift of the curve brought about by reducing phosphate concentration or ionic strength, but tension decreases with the left shift of the curve accompanying substrate concentration reduction in phosphate-free saline. We argue that one mechanism for the observed shift of the curve along the pCa axis is the relationship between the time a cross-bridge takes to complete a cycle and the time Ca2+ stays bound to troponin C (TnC). If the cycle rate is decreased, a smaller fraction to TnC sites must be occupied to keep a given fraction of cross-bridges active. To illustrate this concept, we present a simplified model of the cross-bridge cycle incorporating the kinetics of Ca binding to TnC.

Adenosine Triphosphate↗
PubMed1982

Double immunofluorescence microscopy: a method for localizing immune deposits in skin diseases associated with linear basement membrane zone immunofluorescence.

Direct immunofluorescence microscopy has shown that a linear pattern of immunoglobulin and/or complement deposition at the cutaneous basement membrane zone is a characteristic feature in a number of acquired bullous diseases and is occasionally observed in systemic lupus erythematosus. Immunoelectron microscopy has shown the linear pattern of immunofluorescence may be produced by immune deposits located either above the basal lamina (in the lamina lucida) or below the basal lamina (in the upper dermis). Distinguishing between these sites of immune reactant deposition may be of value in differential diagnosis. In this study we report a double immunofluorescent method by which skin biopsies with linear IgG immunofluorescence due to deposits above the basal lamina (bullous pemphigoid) could be distinguished from biopsies with deposits beneath the basal lamina (bullous systemic lupus erythematosus and epidermolysis bullosa acquisita). When skin sections were treated sequentially with rhodamine-labeled anti-human IgG followed by fluorescein-labeled antilamina lucida (pemphigoid) antibody and examined by fluorescence microscopy, the following results were obtained. In biopsies with IgG deposits in the lamina lucida, a single green fluorescent band was observed. In tissues with subbasal lamina deposits, either parallel and contiguous bands of green and yellow-orange fluorescence or a single band of yellow-orange fluorescence was observed. The method is simpler, quicker, and less expensive than immunoelectron microscopy and should be a useful technique for evaluating skin diseases with linear immunofluorescence at the basement membrane zone.

Basement Membrane↗
PubMed1982

Clinical comparison of high-speed rare-earth screen and par-speed screen for diagnostic efficacy and radiation dosage.

One hundred patients underwent excretory urography and a comparison was made of ten-minute, well-collimated images that were obtained with both par-speed and rare-earth screens, the latter being 6.5 times faster than the par-speed calcium tungstate screens. Radiation dose was greatly reduced with the rare-earth screens. There were fewer inferior examinations, even though fine detail was imaged poorly, and there was a slightly increased quantum mottle, which was only a minor problem at this low 65 kVp. Since quantum mottle increases with kVp, however, our results are not applicable to higher kVp examinations. Despite reduced detail and increased mottle, the overall image quality obtained with the rare-earth screen was superior to the image quality obtained with the par-speed screen.

Body Burden↗
PubMed1981

Renal failure induced by contrast material.

Transitory and occasionally irreversible renal failure secondary to parenterally administered iodinated contrast material is now well documented. Diabetes and pre-existing renal insufficiency are the two most important risk factors. Intravascular contrast examinations should be avoided whenever possible in high-risk patients, particularly diabetics with creatinine levels of 5 dl./ml. or higher. Alternative methods for the etiologic evaluation of renal failure or hematuria are suggested.

Contrast Media↗
PubMed1978

Sarcoidosis and mediastinal emphysema.

Mediastinal emphysema developed in a 13-year-old boy with diffuse interstitial pulmonary disease, later proved to be sarcoid. No previous report was found.

Adolescent↗
PubMed1977

Pathogenesis of an unexpected sudden death: role of early cycle ventricular premature contractions.

A 61 year old man who had been studied extensively died unexpectedly ("instantaneously") outside the hospital while wearing an electrocardiographic recorder. Death was caused by ventricular fibrillation, which was initiated by an early cycle ventricular premature contraction occurring in the vulnerable period of repolarization. Such early cycle ventricular premature contraction had been noted in recordings 4 years previously but had never been observed to encroach on the T wave until 5 minutes before death. In the intervening period, the patient had shown increasing evidence of myocardial ischemia and hypertrophy and congestive heart failure, which had been partly obscured by his concealment or denial of symptoms and refusal to change his pattern of activities. Autopsy revealed two old myocardial infarcts and pronounced left ventricular hypertrophy. There was advanced occlusive arteriosclerosis of the major coronary vessels with a recent thrombus in the right coronary artery.

Arrhythmias, Cardiac↗
PubMed1976

Piebaldism.

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Adolescent↗
PubMed1976

Lichen aureus.

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Child↗