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Biomedical subjects

R David

Publications and source records attributed to R David.

At least 109 records · Page 6Linked to original sources
PubMed1989

Circumferential perirenal urinoma mimicking nephromegaly on urography.

Four cases of circumferential perirenal urinoma in patients with cancer are described. Intravenous urography showed evidence of apparent renal enlargement. In 1 case, opacification of extravasated urine was dense enough to be seen on the urogram, and the diagnosis was confirmed by computed tomography (CT). In the other cases, sonography followed by CT diagnosed urinoma, after tumor invasion had been suggested because of the pseudonephromegaly. Ureteral obstruction was demonstrated in all cases, due to retroperitoneal adenopathy in 1 case and to pelvic tumor in the other 3. Sonography or CT is required for the diagnosis of circumferential perirenal urinoma mimicking nephromegaly urographically.

Adult↗
PubMed1989

Plasmodium falciparum: DNA probe diagnosis of malaria in Kenya.

We previously reported isolation of DNA probe which specifically recognizes Plasmodium falciparum and developed a simple method for its use. The sensitivity and specificity of this DNA probe method have now been extensively field tested in comparison with those of conventional microscopic examination of blood films in two separate studies in Malindi, Kenya, involving a total of 1179 patients. In the second study, which used improved techniques, sensitivity of the DNA probe was 89% when compared to microscopy. We conclude that the DNA probe method compares favorably with conventional microscopy in detecting parasite densities as low as 25 parasites per microliter of blood. A significant advantage of the DNA probe method is that it utilizes a standardized procedure which can simultaneously and reproducibly analyze a large number of samples without opportunity for significant reader bias.

Adult↗
PubMed1989

Myofibroblasts in peripheral giant cell granuloma. Light and electron microscopic study.

Myofibroblasts are found in various pathologic conditions including lesions containing giant cells, such as central giant cell granuloma and the giant cell tumor of tendon sheath (nodular tendosynovitis). In the present study, myofibroblasts were found in peripheral giant cell granuloma (PGCG) using the TP-Levanol fast cyanine 5RN histochemical procedure and electron microscopy. A number of myofibroblasts displayed intracellular collagen fibrils. The presence of myofibroblasts supports the reactive nature of PGCG.

Fibroblasts↗
PubMed1989

The clavicle: normal and abnormal.

The clavicle is an unusual long bone with many unique embryologic features. It is often involved in congenital and acquired disorders. Traumatic, inflammatory, neoplastic, metabolic and many other miscellaneous lesions may also affect the bone. Because of its ligamentous attachments and the presence of articulations at both ends, the clavicle can also be involved in arthritic diseases. This article illustrates the radiographic manifestations of many of the disorders of the clavicle that are commonly encountered in clinical practice.

Bone Diseases↗
PubMed1989

The many faces of neuroblastoma.

Neuroblastoma is a common tumor in childhood. It arises in the adrenal gland or in various extraadrenal primary sites of the sympathetic chain. Clinically, it may present as an abdominal mass or as disseminated metastatic disease. We studied 52 patients with neuroblastoma, and the typical and unusual radiographic features of the disease are presented.

Adrenal Gland Neoplasms↗
PubMed1989

Bladder diseases and imaging methods.

New and exciting diagnostic modalities which substantially change the evaluation of the urinary bladder have become available in the last decade. This is a review of the principles involved in and the advantages of diagnostic imaging using the modalities available to study the urinary bladder in a modern radiologic facility. It emphasizes the values of the different modalities in specific disease states. Excretory urography, cystography, and voiding cystourethrography were the mainstay of the evaluation of bladder pathology. These modalities are still good screening methods under certain circumstances but are relatively limited in comprehensive assessment of the bladder. Bladder studies using radionuclides, such as nuclear cystography, still have a space in the long-term follow-up of pediatric patients due to their relative low radiation dose. Since the addition of ultrasonography, computed tomography, and more recently, magnetic resonance imaging to the radiologist's armamentarium of imaging modalities, there has been a tremendous improvement not only in the demonstration of bladder abnormalities, but also in the staging of bladder neoplasms. The relative merits of these past and present imaging modalities are illustrated. Their appropriate contributions to improved quality of care of patients with bladder disease are also discussed.

Humans↗
PubMed1989

Acromegaly in an infant.

Serial hormonal studies were carried out in a girl with a growth hormone-secreting pituitary adenoma and hyperprolactinemia diagnosed at 21 months of age, the youngest verified case of acromegaly. The child had progressive macrocephaly, noted at 6 months of age, which preceded the rapid acceleration of linear growth by nearly 1 year. At 21 months of age, the girl's head circumference measured 55 cm (+5.5 SD) and her height was 97.6 cm (+4.4 SD). Preoperative serum growth hormone level was 135 ng/mL, somatomedin C was 1,540 ng/mL (normal for bone age 18 to 97 ng/mL), and prolactin was 370 ng/mL (normal less than 20 ng/mL). Following total resection of a large adenoma, immunohistochemical staining of the tumor showed growth hormone but not prolactin. With longitudinal monitoring of the child for 2 years postoperatively, persistently low growth hormone levels were demonstrated and normal growth velocity (6 cm/yr). Peak serum growth hormone levels ranged from 2.8 to 4.1 ng/mL after stimulation tests with insulin, arginine, and L-dopa. Maximum sleep-entrained growth hormone level was 3.4 ng/mL. At the same time, serum somatomedin C levels measured serially were normal (29 to 111 ng/mL), whereas simultaneous prolactin levels were moderately increased (30 to 147 ng/mL). The data support the hypothesis that hyperprolactinemia may have contributed to stimulating somatomedin C and sustaining the normal growth rate in this child.

Acromegaly↗
PubMed1988

Coagulation activities of plasma microparticles.

An evaluation of the effect of plasma microparticles (MP) on in vitro coagulation has been undertaken using platelet rich (PRP), platelet poor (PPP) and platelet free (PFP) plasmas prepared by differential centrifugation. MP provide coagulant material which shortens the activated partial thromboplastin time (APTT) and dilute simplastin time (DSTT) which is different from that contributed by commercial phospholipid preparations. The amount of platelet factor three (PF3) available in plasma is directly correlated with the centrifugal force used in its preparation and is present in large amounts in the MP pellet remaining after preparation of PFP. Factor VIII (F.VIII:C) and von Willebrand factor (vWf) were associated with the MP fraction but could be separated from MP on sucrose gradients. The effect of MP on the APTT was independent of the F.VIII:C/vWf and was not solely due to their PF3 content. Plasma prepared for routine coagulation assays contains MP which contribute to the APTT and DSTT and should be considered in their assessment. High speed centrifugation of plasma reduces the F.VIII:C/vWf:Ag/RCoF levels and this may contribute to losses of these proteins during preparative procedures utilising high speed centrifugation.

Adult↗
PubMed1988

Anterior dynamic imaging of the liver and spleen.

Anterior dynamic imaging of the abdomen was performed in 870 patients using a large field-of-view (LFOV) gamma camera. Sequential images were obtained immediately after the injection of Tc-99m sulfur colloid (Tc-99m SC) in an antecubital vein for liver-spleen imaging and was followed by standard planar images. This provided additional information in 172 cases (20%), including such findings as determination of the lesion's vascularity in 76 (9%), visualization of abnormal portal blood flow in 53 (6%), and detection of abnormalities in the aorta, inferior vena cava, iliac vessels, or kidneys in 43 (5%) of these patients. This procedure is recommended in all patients undergoing liver-spleen imaging.

Adult↗