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Biomedical subjects

J C Walton

Publications and source records attributed to J C Walton.

32 records · Page 2Linked to original sources
PubMed1990

Primary gastric T-cell lymphoma of suppressor-cytotoxic (CD8+) phenotype: discordant expression of T-cell receptor subunit beta F1, CD7, and CD3 antigens.

Primary gastric T-cell lymphomas are rare neoplasms, and all but one of the previously phenotyped cases have shown a helper-inducer phenotype. The present case is the second reported case of a primary gastric T-cell lymphoma of suppressor-cytotoxic phenotype. The tumor histology was similar to that described in some forms of node-based peripheral T-cell lymphomas. Phenotypic analysis revealed low expression of pan-T marker CD7, reduced expression of CD3, but higher density and frequency of expression of CD8 antigens that could be predicted on the basis of the pan-T markers. Natural killer cell (NK) related markers CD16, HNK-1 and NKH-1 were not expressed by the neoplastic cells. T-cell receptor (TCR) beta subunit expression was detected on fewer cells than would have been predicted on the basis of CD3 and CD8 expression, and TCR delta chain expression was undetectable.

Aged↗
PubMed1990

Immunogold quantitation of immunoglobulin light chains in renal amyloidosis and kappa light chain nephropathy.

By quantitative immunoelectron microscopy using protein A-gold, the authors compared the content and distribution of immunoglobulin light chain (LC) antigens in glomeruli from 11 cases of renal amyloidosis with that in two cases of kappa LC glomerulopathy and two cases of diabetic glomerulosclerosis. In a supplementary study and using a similar immunogold technique, the authors identified amyloid A in deparaffinized renal tissue from three of the 11 cases of renal amyloidosis. Each patient had similar clinical manifestations (chronic renal failure with proteinuria) and similar glomerular morphology (thickened glomerular basement membranes and nodular expansion of the mesangium). In 12 cases (10 amyloid, 2 kappa LC), immunoelectron microscopy localized LC antigens over the glomerular deposits and allowed indirect tissue quantitation of each LC antigen to the various cellular and interstitial compartments. In 6 of the 11 cases of renal amyloidosis, the amyloid labeled only for lambda, and in one, only for kappa. In one patient with Waldenström's macroglobulinemia, who had a biclonal gammopathy, both LC were identified in the amyloid. In two cases, both of whom had a history of chronic suppurative lung disease, both LC antigens as well as amyloid A were localized to the amyloid fibrils. In only one case, in which glomerular amyloid labeled for amyloid A, the amyloid did not label for either LC. Whereas lambda LC-derived fibrils often appeared as spicules in the glomerular subepithelial space, other amyloid deposits usually accumulated in the subendothelial zone and did not form spicules. The epimembranous location of spicules suggested that the amyloid precursor protein transformed into amyloid fibrils after filtration into the urinary space. Presence of epimembranous spicules may explain the more severe proteinuric renal failure and the more rapid progression to glomerulosclerosis described in primary amyloidosis.

Amyloidosis↗
PubMed1986

Chronic ileal obstruction in adults due to peri-ileal vitelline vascular remnants.

Two young adults had distal ileal obstruction at sites where a fold of mesentery extended from its posterior leaf to the antimesenteric border of the bowel. No Meckel's diverticulum or mesoumbilical band was present in either case. Clinical, gross and microscopic findings suggested that the mesenteric fold represented a remnant of vitelline vessel that persisted in the peri-ileal portion of its course. Chronic ileal obstruction was apparently due to disordered peristalsis caused by the fold tethering the adjoining posterior bowel wall. In one patient, a chronic ulcer at the site of obstruction was interpreted as being an additional complication of the congenital lesion.

Adult↗
PubMed1985

Laryngeal atresia, pleurodesis, and diaphragmatic hypertrophy in a newborn infant with findings relevant to fetal lung development.

A rare congenital malformation, cartilaginous subglottic laryngeal atresia, was found associated with developmental growth disturbances in the lungs (hypoplasia), diaphragm (hypertrophy), and pleural cavities (pleurodesis) in a newborn premature male infant who died immediately after birth. Because of coexistent esophageal atresia, tracheoesophageal fistula, and anal atresia, the lower respiratory tract and gastrointestinal canal together formed a closed system throughout fetal life. A mechanism whereby diaphragmatic hypertrophy and mesenchymal obliteration of the pleural cavities may have evolved during uterine development is suggested. Since pulmonary hypoplasia was also present, an explanation of this unique constellation of development abnormalities has a bearing on normal lung development.

Abnormalities, Multiple↗
PubMed1984

Iron deposits and multiple sclerosis.

A recent publication described autopsy samples from five brains in which positive staining for iron was observed as surrounding demyelinated plaques. Because this has not been previously reported, autopsy material from 13 patients who were being followed up at the Multiple Sclerosis (MS) Clinic, University Hospital, The University of Western Ontario, London, Ontario, was reviewed. A total of 32 paraffin-embedded blocks containing demyelinated plaques of varying age were sectioned and stained using a standard acid ferrocyanide technique (Peris' test) for iron. Microscopic examination failed to detect the presence of significant positive staining either within or surrounding the areas of demyelination. Positive histochemical staining for iron identifies hemosiderin, the presence of which suggests either iron overload or remote hemorrhage. Support for these two processes in the pathogenesis of MS could not be provided from our material.

Autopsy↗
PubMed1983

Electron spin resonance study of the role of vitamin E and vitamin C in the inhibition of fatty acid oxidation in a model membrane.

The neutral alpha-tocopheroxyl radicals, generated in monolayers on silica gel containing alpha-tocopherol and partly autoxidised methyl linoleate at 90 degrees C, were detected and identified by ESR spectroscopy. Addition of ascorbic acid to the monolayer resulted in the complete quenching of the alpha-tocopheroxyl radical spectrum. This lends support to the view that ascorbate transfers hydrogen to alpha-tocopheroxyl radicals thus regenerating alpha-tocopherol.

Ascorbic Acid↗
PubMedDate not supplied

Prostaglandin endoperoxide synthase kinetics in human amnion before and after labor at term and following preterm labor.

To determine whether the kinetics of prostaglandin endoperoxide synthase (PGHS, commonly known as cyclooxygenase) in human amnion change with labor onset or between preterm and term labor, a specific enzyme assay was developed and characterized. The assay was linear for time (0-8 min) and protein concentration (5-30 micrograms/250 microliters incubation volume). The optimum pH was 8.0-8.5, and the enzyme reaction reached saturation at 10-20 microM arachidonic acid. Flufenamic acid was more efficacious than ibuprofen in the presence of 1 mM tryptophan in inhibiting enzyme activity. The Km and Vmax of PGHS were determined in 10 amnions obtained at elective caesarean section before labor onset (CS) at 39.3 +/- 0.8 wk gestational age (mean +/- SD, range = 38.5-41 wk) and 9 amnions obtained following spontaneous labor and vaginal delivery (SL) at 39.6 +/- 0.8 wk (range = 38.5-41 wk). The Km values were 1.4 +/- 1.2 mumol/l (CS) and 2.2 +/- 1.5 mumol/l (SL) (not different). However, the Vmax increased significantly (p < 0.05) from 11 +/- 8 (CS) to 19 +/- 4 (SL) pg PGE2/micrograms protein/min. In eight preterm amnions obtained following spontaneous labor and delivery at 32.9 +/- 2.1 wk (range = 29-36 wk), the Km and Vmax were 2.0 +/- 1.2 mumol/l and 17 +/- 9 pg PGE2/micrograms protein/min, respectively. Neither of these values was different from those of CS or SL amnions. None of the preterm pregnancies displayed histological evidence of infection. These results suggest that an increase in the mean amnion PGHS maximum velocity occurs in association with the onset of labor at term. The mean Vmax of PGHS in amnions obtained from idiopathic preterm spontaneous deliveries is between the CS and SL term values, reflecting, perhaps, multiple etiologies for preterm delivery.

Amnion↗
PubMedDate not supplied

Immunoreactive 15-hydroxyprostaglandin dehydrogenase (PGDH) is reduced in fetal membranes from patients at preterm delivery in the presence of infection.

Previously we reported that the proportion of trophoblast cells that were immunopositive for 15-OH prostaglandin dehydrogenase (PGDH) in the chorionic membranes was reduced in women in preterm labour without infection, compared with women at term, but was not altered in preterm labour patients with an underlying infective process. Subsequently, we found that PGDH activity and PGDH mRNA were significantly lower in membranes of this latter group of patients than in women at preterm labour without infection or at term. To resolve this issue we used immunohistochemistry to examine the distribution and frequency of immunoreactive (ir)-PGDH positive cells in full-thickness fetal membranes in patients at preterm labour in the presence or absence of infection. Trophoblast and decidual stromal cells were identified using antibodies against cytokeratin and vimentin, respectively. There was considerable variation in the number of chorionic trophoblast cells that were positive for ir-PGDH, but in some patients there was little or no ir-PGDH staining, and this was associated with loss of trophoblast cells from the tissue. The mean intensity and number of ir-PGDH positive cells was significantly lower in membranes from patients in preterm labour with infection than in idiopathic preterm labour at which the diagnosis of infection was not made. We conclude that in the setting of preterm labour with infection there may be loss of trophoblast cells from membranes, with corresponding reduction in the number of ir-PGDH positive cells. Loss of PGDH activity removes the initial step in activating primary prostaglandins, which are then able to pass unmetabolized to the decidua and myometrium, and contribute to the stimulus to preterm birth.

Chorion↗