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Biomedical subjects

R Baumal

Publications and source records attributed to R Baumal.

At least 109 records · Page 6Linked to original sources
PubMed1984

Salivary gland monomorphic adenoma. Ultrastructural, immunoperoxidase, and histogenetic aspects.

Monomorphic adenoma of basal cell type is a salivary gland tumor believed to result from a proliferation of a single type of cell. However, ultrastructural and immunocytochemical investigations of 6 monomorphic adenomas (5 from parotid and 1 from intraoral minor salivary gland) indicate that there are two classes of these lesions, one composed of two types of tumor cells and the other wholly or predominantly made up of one type of cell (isomorphic). In the former group, the organization of the tumor cells closely mimicked that of normal and hyperplastic salivary gland intercalated ducts. Aggregates of tumor cells were arranged as an inner layer of luminal epithelial cells which were surrounded by an outer layer of cells that, in some cases, had ultrastructural and immunohistochemical features indicating myoepithelial cell differentiation. In some adenomas formed by two types of tumor cells, basal-lamina-lined extracellular spaces were identified ultrastructurally in relation to modified myoepithelial cells; such spaces had the same fine-structural features as those reported in pleomorphic adenoma and adenoid cystic carcinoma. Predominantly isomorphic adenomas were composed exclusively of luminal epithelial cells. These results indicate that despite the varied histologic patterns in the numerous subtypes of monomorphic adenoma, there is a central theme of differentiation and organization in this type of neoplasm which recapitulates the ductoacinar unit of normal salivary gland parenchyma.

Adenoma↗
PubMed1984

Outer medullary circulatory defect in ischemic acute renal failure.

Changes in medullary circulation may contribute significantly to the pathogenesis of ischemic acute renal failure. The microcirculation of the outer medulla of the rat kidney was studied by morphometry, carbon injection, and scanning electron microscopy of vascular casts after temporary renal ischemia. Morphometry showed a markedly reduced vascular area and an increased tubular epithelial cell area in the outer stripe of the medulla 2 hours after blood reflow. Maximum diminution in vascular area occurred 24-48 hours after reflow, with swollen and later necrotic tubular epithelium compressing the surrounding vascular compartment. Outflow blockade of venous vasa recta in the outer stripe caused congestion of the inner stripe. Carbon injection and scanning electron microscopy of vascular casts confirmed the perfusion defects of the outer stripe. These results suggest that decreased blood reflow to the outer stripe of the medulla secondary to tubular epithelial cell swelling and necrosis plays a significant role in the pathogenesis of ischemic acute renal failure in the rat.

Acute Kidney Injury↗
PubMed1984

Response to cyclophosphamide in steroid-resistant focal segmental glomerulosclerosis: a reappraisal.

The response to and clinical outcome of cyclophosphamide therapy were retrospectively assessed in 29 steroid-resistant patients with idiopathic nephrotic syndrome and focal segmental glomerulosclerosis (FSGS) to determine whether a partial response to this drug was associated with long-term clinical benefits. Twenty of the patients were nephrotic when cyclophosphamide was started and 9 were not. Three of the nephrotic patients had a complete response (i.e., sustained remission of disease) to cyclophosphamide. Nine nephrotic patients had partial responses. Of these, 8 have residual proteinuria and one has progressed to end-stage renal disease (ESRD). In contrast, of the 8 nephrotic patients who were resistant to cyclophosphamide, only one has residual proteinuria, while 7 have chronic renal failure (CRF) or ESRD. The incidence of CRF or ESRD in patients with a partial response to cyclophosphamide (1 of 9) was significantly lower (p = 0.004) than that in patients who were resistant to cyclophosphamide (7 of 8). The benefit of cyclophosphamide in patients who were not overtly nephrotic was less certain. This study indicates that a partial response to cyclophosphamide leads to improvement in the clinical outcome of many steroid-resistant nephrotic patients with FSGS.

Adolescent↗
PubMed1984

The significance of focal segmental glomerulosclerosis in oligomeganephronia.

Oligomeganephronia (OMN) is characterized by a reduced number of nephrons, with compensatory hypertrophy of the remaining glomeruli and tubules. The clinico-pathological features of six cases seen at The Hospital for Sick Children, Toronto were reviewed. One patient presented in infancy (10 days of age), the others between 12.8 and 14.5 years (mean 13.7 years), with long-standing polydipsia and polyuria, enuresis, and growth retardation. All patients had proteinuria which tended to increase as the disease progressed. At renal biopsy, four patients showed significant proteinuria (greater than 1.3 g/24 hr). Biopsies from these patients showed focal segmental glomerulosclerosis (FSGS) and all have rapidly progressed to dialysis/transplantation. The two remaining patients had lesser degrees of proteinuria (less than 0.3 g/24 hr) and no evidence of FSGS on biopsy; however, they are currently in chronic renal failure (mean serum creatinine 2.8 mg/dl). We conclude that increasing proteinuria in patients with OMN heralds the development of FSGS, presumably due to functional overload of the reduced nephron number. This is associated with a rapid decline in renal function.

Adolescent↗
PubMed1984

Focal segmental glomerulosclerosis and progressive renal failure associated with a unilateral kidney.

Persistent proteinuria, chronic renal failure, and focal segmental glomerulosclerosis developed in three children with solitary kidneys. Two of these children were born with unilateral kidneys. The third had bilateral reflux and underwent a unilateral nephrectomy and reimplantation of the remaining ureter; persistent proteinuria developed 7 years later. It is postulated that hyperperfusion of a critical number of glomeruli during childhood may be the mechanism responsible for the production of focal segmental glomerulosclerosis in these patients.

Adolescent↗
PubMed1983

Immunohistochemical and electron microscopic assessment of childhood rhabdomyosarcoma. Increased frequency of diagnosis over routine histologic methods.

Histologic examination was carried out in 65 cases of childhood rhabdomyosarcoma (RMS), 53 embryonal, and 12 alveolar. Cross-striations were seen on light microscopy in 12 (23%) embryonal and 4 (33%) alveolar tumors. The capacity of immunohistochemical staining (PAP technique) to increase diagnostic accuracy was assessed, using antibodies against myoglobin, the MM isoenzyme of creatine kinase, desmin, calcium magnesium-dependent ATPase of sarcoplasmic reticulum and calsequestrin. Myoglobin was detected in 16 (30%) embryonal and eight (67%) alveolar RMS, higher numbers than obtained by viewing cross-striations on light microscopy. The creatine kinase antibody was slightly better than the antibody to myoglobin and 15 of 25 (60%) embryonal RMS were positive when both specificities were used. The remaining three antibodies were less useful. Of 13 (two alveolar and 11 embryonal) RMS studied by electron microscopy, four showed cross-striations, contained late myoblasts, and were positive for myoglobin. Three additional cases showed only late myoblasts and one of these was positive for myoglobin. Thus, 16 of 25 (64%) of the embryonal and seven of nine (78%) of the alveolar RMS showed either positive immunostaining or ultrastructural features of RMS. This study indicates that a combination of immunohistochemical staining, using antimyoglobin and anticreatine kinase (MM isoenzyme) antibodies, and electron microscopy are useful markers in the diagnosis of childhood RMS.

Ca(2+) Mg(2+)-ATPase↗
PubMed1983

Categorization of pediatric neoplasms by immunostaining with antiprekeratin and antivimentin antisera.

Forty-six tumors in children were examined using light microscopy and subsequently frozen sections were stained with antiprekeratin and antivimentin antisera, so that the tumors could be classified by tissue of origin. Except for two adrenal cortical carcinomas and four liver tumors, most epithelial neoplasms continued to produce prekeratin filaments, a characteristic of normal epithelial cells. Tumors and cells of epithelial origin did not produce vimentin filaments, whereas normal and neoplastic mesenchymal cells did. Tumors with both epithelial and mesenchymal components produced vimentin filaments in mesenchymal areas and prekeratin in epithelial areas. Tumors of lymphoid origin showed variable production of vimentin filaments, depending on the amount of cell cytoplasm, but did not contain prekeratin filaments. Of the neuroectodermal tumors, only the ganglioneuroma contained vimentin filaments and none contained prekeratin filaments. Thus, antibodies to both prekeratin and vimentin filaments are useful in diagnosing childhood neoplasms and studying their histogenesis.

Child↗
PubMed1983

Localization and identity of adenosine deaminase-positive cells in tissues of the young rat and calf.

Rabbit antibody to calf adenosine deaminase (ADA) was used to localize this enzyme in tissues of the young rat and calf by the immunoperoxidase method. The distribution patterns of ADA in most tissues were similar for both species. Within the thymus gland, the enzyme was strongly expressed predominantly in cortical lymphocytes. In the spleen and lymph nodes, most lymphocytes of T-cell areas stained weakly for ADA, whereas only a small number of ADA-positive cells were found in B-cell areas. Clumps of strongly ADA-positive mononuclear blastoid and plasma cells were observed in the medullary regions of lymph nodes, around peri-arteriolar lymphocyte sheaths and in the red pulp of the spleen, and in the lamina propria of the intestine. Double immunofluorescence staining studies in the rat showed that some of these blastoid cells contained both ADA and immunoglobulins and appeared to be plasmablasts. Strong staining for ADA was also found, in both the rat and calf, in as yet unidentified mononuclear blastoid cells in the interstitium of non-lymphoid organs (kidney, heart, lung), in endothelial cells of some arterioles and capillaries, and in Kupffer cells of the liver. In addition, ADA was strongly expressed in calf bile canaliculi. These studies define areas in rat and calf tissues which contain ADA-positive cells and provide a model system for investigations of the relationship between ADA and the function and development of these cells.

Adenosine Deaminase↗
PubMed1983

Characterization of idiotopes on MOPC 315 IgA using monoclonal antiidiotypic antibodies.

The isologous antiidiotypic response in BALB/c mice to immunization with the DNP-binding IgA myeloma protein, MOPC 315, alters the expression of the anti-DNP antibody repertoire and confers immunity against MOPC 315 myeloma tumors. In order to characterize the idiotopes on MOPC 315 IgA which elicit this response we have isolated four monoclonal antiidiotypic antibodies (AIA) D10 (IgG2a), A2(IgG1), G3 (IgG2b) and F1 (IgG2a), produced by splenocytes of BALB/c mice immunized with MOPC 315 IgA in three independent fusion experiments. These AIA react with MOPC 315 IgA, reassociated H315 L315 and FV31¿5 but not with free H315, L315, VH315 or VL315. In addition the AIA do not react with the closely related DNP-binding IgA myeloma protein, MOPC 460, suggesting that they are directed against private idiotopes on MOPC 315 IgA. These idiotopes can be divided into two groups. Group I, defined by D10, A2 and G3 consists of two overlapping idiotopes, one of which is related to the hapten-binding site. The two idiotopes are formed by an interaction of amino acids in H315 and L315. Group II defined by F1 consists of one idiotope which is related to the hapten-binding site. This idiotope is comprised of an amino acid sequence on H315 which requires an interaction with either L315 or L460 for expression. A2 and G3 react identically with the same idiotope but were derived from two independent fusion experiments. This indicates an identity of AIA clonotypes among individual mice and suggests that the isologous AIA response to MOPC 315 IgA is restricted.

Animals↗
PubMed1983

Origin of the desmoplasia in desmoplastic malignant melanoma.

Four cases of desmoplastic malignant melanoma were examined light microscopically and immunohistochemically. Electron microscopy was performed in three cases. Light microscopy showed that all tumors were composed of neoplastic spindle cells that infiltrated between mature collagen bundles in the reticular dermis. Some of the spindle cells had bizarre nuclei, whereas other spindle cells resembled normal fibroblasts. Melanin could not be demonstrated in any of the tumors by histochemical techniques. Electron microscopic examination of the spindle cells showed prominence of rough endoplasmic reticulum, which was dilated and filled with flocculent material and occasional collagen fibrils. The same cells contained aggregates of non-membrane-bound melanin granules and pre-melanosomes. Some cells also showed features of myofibroblasts. Immunoperoxidase staining with anti-S100 protein antibody demonstrated positivity of the spindle cells as well as of melanocytes in the basal layer of the epidermis. Scar tissue and fibroblasts did not stain. These findings show that the desmoplastic component of these malignant melanomas derives from melanocytes that have undergone adaptive fibroplasia. Therefore, in assessing depth of invasion in a malignant melanoma, measurements should include the desmoplastic areas.

Adult↗
PubMed1983

Role of antibody to S100 protein in diagnostic pathology.

Normal tissues and various tumors were examined for S100 protein, using anti-S100 protein antiserum, in an immunoperoxidase reaction. Among normal tissues, in addition to the previously reported presence of S100 protein in some neurons, glial, and Schwann cells of the nervous system, melanocytes and Langerhans cells of the skin, interdigitating reticulum cells of lymph nodes, and chondrocytes, we demonstrated it in myoepithelial cells and ducts of sweat glands, salivary glands, and the breast, serous glands of the lung, fetal neuroblasts, and sustentacular cells of the adrenal medulla. Among neoplasms, S100 protein previously has been reported in neurogenic tumors, melanomas, and neuroblastomas; we have demonstrated it in mixed sweat gland tumors, histiocytosis X, pleomorphic adenomas of the salivary gland, medullary carcinomas of the breast, bronchioloalveolar carcinomas of the lung, sustentacular cells of pheochromocytomas, teratomas of the ovary, and tumors of cartilage (enchondromas, osteochondromas, and chondrosarcomas). With S100 protein producing tumors, a normal progenitor cell was identified, indicating that demonstration of S100 protein in tumors confirmed their origin.

Carcinoma↗
PubMed1983

The structural conservation of S100 protein during evolution: analysis by reactivity with a monoclonal antibody.

A hybridoma cell line producing a monoclonal antibody (A4) against bovine S100 protein has been produced by fusing mouse myeloma P3X63/Ag8 cells with spleen cells from a BALB/c mouse immunized with bovine S100 protein. A4 is of the IgG2b subclass and was purified by affinity chromatography on a protein A-Sepharose column. Brain extracts from several mammalian and one avian species reacted both with polyclonal rabbit anti-S100 protein antiserum and with A4 in a radioimmunoassay. Brain extract from dog was a notable exception. It reacted with the rabbit antiserum but not with A4. Therefore A4 reacts with a common epitope that is present on S100 proteins from different vertebrate species but is absent on dog S100 protein.

Animals↗
PubMed1983

Time course of morphometric changes after acute allergic bronchoconstriction in the guinea pig.

Experimental allergic bronchoconstriction was induced in guinea pigs by passive sensitization with a standard dose of homologous antiserum followed by challenge with aerosolized antigen. Lungs were removed from animals at intervals of up to 6 days thereafter, and several parameters of the reaction were assessed morphometrically by comparison with lungs from unsensitized guinea pigs. We determined all changes in volume of the lung tissue resulting from fixation through to the preparation of histologic sections, but no significant differences were observed between the time course subgroups. The size of both large and small airways was assessed by a point-counting technique, as well as by measurement of the percentage of the diameter of the airways contributed by the mean thickness of the muscular layer. Maximal bronchoconstriction was observed morphometrically to correspond with the peak of a response as determined clinically by the use of a strain gauge around the chest. This was followed by a return to normal of the airway size. The number of mast cells and eosinophils around large and small airways, around branches of the pulmonary artery and in random fields of the lung parenchyma was tabulated. The maximal decrease in mast cells was seen in animals which died immediately following challenge, but the numbers were not restored to the control level even in animals which had survived for 6 days. The greatest increase in eosinophil response occurred in lungs obtained 10 min following challenge. This model will be of value in determining the effects at the tissue level of pharmacological inhibitors of this reaction.

Acute Disease↗
PubMed1983

Cadaveric renal transplants in children under 6 years of age.

Thirty-nine cadaveric renal allografts were performed in 28 children under 6 years of age. Common primary renal diseases were glomerulonephritis, dysplasia/hypoplasia, and reflux/obstructive nephropathy. After a mean follow-up of 40 months of patients with surviving grafts, 19 patients had functioning grafts, 3 had returned to dialysis, and 6 had died. These children required an extraordinary amount of care postoperatively because of anorexia, diarrhea, and ileus. Their psychomotor and physical development was retarded prior to transplant; this reversed dramatically after transplant, but catch-up growth occurred in only 4 patients. Many patients were noticeably more active and distractible for 1 to 2 years post-transplant. Major causes of graft failure were primary nonfunction of 5 donor kidneys (4 from donors under 1 year old) and renal vessel thrombosis in 5 recipients (3 with native kidneys in place who received kidneys from donors over 10 years old). Other causes were recurrence of hemolytic uremic syndrome and Wilms tumor, rejection, and sepsis. Kidneys from donors under 1 year old proved unsatisfactory, and large donor kidneys in small children tended to thrombose, especially when native kidneys with high urine output were left in situ.

Body Height↗
PubMed1983

Characteristics of a benign subtype of dense deposit disease: comparison with the progressive form of this disease.

Pathologic, clinical and serum complement studies were performed on 18 patients with dense deposit disease (DDD). The patients were divided into 3 groups: group A (10 patients who developed end-stage renal failure within 2.9 +/- 1.0 years of onset) group B (3 patients who developed elevated serum creatinines within 6.8 +/- 4.8 years of onset) and group C (5 patients with no evidence of renal insufficiency after 11.0 +/- 1.4 years of follow-up). Renal biopsies from all patients showed intramembranous, electron-dense deposits in glomerular capillary basement membranes. Most group A and B patients presented with a nephritic and/or nephrotic syndrome and followed an active clinical course. In contrast, group C patients presented with either a nephrotic syndrome or asymptomatic proteinuria +/- hematuria and followed a benign course. Sera from group A and B patients contained reduced concentrations of C3 and factor B and large amounts of C3 nephritic factor (NeF) activity. In contrast, serum of group C patients contained normal amounts of C3 and factor B and low levels of C3 NeF activity. These studies show that some patients with DDD (group C) have a benign illness and that they can be identified by serum levels of C3, factor B and C3 NeF activity.

Child↗
PubMed1982

Focal segmental glomerulosclerosis with idiopathic nephrotic syndrome: three types of clinical response.

In a retrospective analysis, 51 patients with focal segmental glomerulosclerosis and idiopathic nephrotic syndrome, who were treated with steroid or cyclophosphamide therapy, were divided into three clinical groups according to the remission profile of their nephrotic syndrome. Group 1 patients (19.37%) consistently responded to medication; none has progressive renal failure (mean follow-up 10.6 years). Group 2 patients (25, 40%) failed to respond to medication; terminal renal failure has occurred in 12 of them. Group 3 patients (7, 14%) initially appeared to be responsive to medication and continued to respond for up to 18 months, but subsequently became unresponsive to any therapy; five of them have required dialysis or transplantation. This third group of patients could not be separated clinically or pathologically from group 1 patients, all of whom have an excellent prognosis. One should, therefore, be cautious about predicting the outcome of steroid-responsive nephrotic patients, especially those with FSGS, until at least 18 months after the onset of illness.

Acute Kidney Injury↗
PubMed1982

Idiopathic membranous glomerulopathy in Canadian children: a clinicopathologic study.

The 1,205 renal biopsies performed at The Hospital for Sick Children, Toronto, were reviewed to identify membranous glomerulopathy. Fourteen patients had a clinicopathologic diagnosis of idiopathic membranous glomerulopathy. Typical thickening of glomerular capillary basement membranes, a spike-and-dome pattern, and subepithelial electron-dense deposits were noted. Strong deposits of IgG and weaker deposits of C3, IgM, and IgA were present in glomeruli. Stages of membranous glomerulopathy on electron microscopy were I in one biopsy, II in nine biopsies, and III in four biopsies. Two additional biopsies from one child initially showed minimal lesion-type disease; later, a third showed membranous glomerulopathy. At presentation 11 patients had nephrotic syndrome, seven had hypertension, and eight had hematuria. Now four are in remission, seven have active disease with normal renal function, and three have renal failure. Patients with hypertension tended to do worse than those without. Age at onset, presence of nephrotic syndrome or hematuria, and administration of steroids or immunosuppressive drugs did not adversely affect outcome. Furthermore, clinical outcome did not correlate with stage of disease. Hence pathologic and most clinical features do not predict long-term prognosis in children with membranous glomerulopathy.

Adolescent↗