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Biomedical subjects

D Albert

Publications and source records attributed to D Albert.

At least 73 records · Page 4Linked to original sources
PubMed1987

Lectin receptors of amyloid in corneas with lattice dystrophy.

We analyzed lectin binding patterns of amyloid glycoconjugates in patients with lattice dystrophy of the cornea. Results of paraffin and frozen sections differed in some instances. With paraffin sections, three lectins--wheat germ agglutinin (WGA), Ricinus communis agglutinin I (RCA-I), and concanavalin A (Con A)--stained the abnormal deposits. In frozen sections, the abnormal deposits were stained by five lectins--WGA, RCA-I, Con A, peanut agglutinin (PNA), and soybean agglutinin (SBA). In paraffin sections, PNA and SBA did not stain amyloid deposits. In both paraffin and frozen sections, some lectin-positive deposits corresponded to the Congo red-positive material, whereas others were present surrounding and encroaching on the Congo red-reactive material. This study demonstrates that WGA-, RCA-I-, Con A-, PNA-, and SBA-positive abnormal deposits are present in corneas with lattice dystrophy. Since lectins bind to specific sugar residues, we conclude that the abnormal deposits consist, at least in part, of glycoconjugates and that these glycoconjugates contain oligosaccharides with N-acetylglucosamine/sialic acid, mannose/glucose and terminal beta-galactose residues and chains with terminal beta-galactose-N-acetylgalactosamine disaccharides.

Adult↗
PubMed1987

Relationship of stressful housing conditions to the onset of diabetes mellitus induced by multiple, sub-diabetogenic doses of streptozotocin in mice.

The effect of the stress of crowded housing conditions (10 mice/cage) on the onset of diabetes after multiple, sub-diabetogenic doses of streptozotocin (MSZ) in male C57BL/KsJ mice was investigated. Prior to MSZ treatment, the group-housed and individually-housed animals had similar plasma glucose levels, while the former group's plasma corticosterone (CS) levels were elevated (54 +/- 8 ng/ml, p less than 0.03; 166% of the latter group). The group-housed animals became hyperglycemic (253 +/- 23 mg/dl) 2 days after the MSZ (day 7), with maximum hyperglycemia (506 +/- 23 mg/dl) developing by day 10. The individually housed animals did not become hyperglycemic until day 10 (303 +/- 24 mg/dl, p less than 0.001), and did not reach maximal hyperglycemia until between days 31 and 46, when plasma glucose levels were no longer different from the group-housed mice (507 +/- 37 mg/dl). There was a significant and progressive rise in CS levels of the stressed animals, reaching 218 +/- 25 ng/ml at day 46. The rise in CS of the unstressed animals was not significant until day 46, when the mean value reached 96 +/- 19 ng/ml (p less than 0.001 vs. basal). However, even at the conclusion of the experiment, the mean CS in the stressed animals was still 227% of that in the unstressed group (p less than 0.001). These studies demonstrate that the effects of stress (biochemically documented as an increase in CS levels) act synergistically with streptozotocin to promote an earlier onset of diabetes mellitus in males of this murine strain.

Animals↗
PubMed1986

A method for assessing potential bias among cancer patients recorded as "dead of other causes." Application to cases of intraocular melanoma.

By applying the Cox regression model to 226 cases of intraocular melanoma, the authors detected a statistical association between tumor-related measurements and 42 deaths that were recorded as due to causes other than melanoma within 10 years of follow-up. This association may reflect a number of events, including errors in assignment of cause of death and confounding from any one of several sources.

Eye Neoplasms↗
PubMed1986

Meconium ileus: is a stoma necessary?

During the 15 years from 1970 to 1984, 38 infants, all with cystic fibrosis, were treated for meconium ileus at The Montreal Children's Hospital and Ste-Justine Hospital for Children. Thirteen patients (34%) had complicated meconium ileus that included 7 perforations (2 colon, 5 ileum), 4 volvulus, and 2 atresia with meconium pseudocyst. In this group, various operations were done: resection with primary anastomosis for atresia, or resection with enterostomy for peritonitis or volvulus. One died shortly after surgery. Of 25 patients with uncomplicated meconium ileus (66%), one died shortly after arrival from respiratory distress, leaving 24 patients available for study. Gastrografin enema was attempted on 20 patients with eight successes (40%). Of the remaining 16 patients with unresolved meconium ileus, nine were treated with laparotomy and ileostomy, and one with laparotomy and T-tube irrigation. Six patients were treated by laparotomy and enterotomy for irrigation with N-acetylcysteine and evacuation by Fogarty catheter, a technique not widely used. No one succumbed in this group. This latter method of management is recommended for patients with simple uncomplicated meconium ileus.

Cystic Fibrosis↗
PubMed1986

Spontaneous deep vein thrombosis in childhood and adolescence.

Deep vein thrombophlebitis (DVT), unrelated to intravenous catheters, is unusual in children. During the period between 1970 to 1984, 15 cases of spontaneous DVT were seen at The Montreal Children's Hospital. The female to male ratio was 2:1. Age ranged from 10 to 17 years. Venogram was positive in the 14 patients in whom it was done. Significant factors were related to the DVT in 12 patients: oral contraceptives, pelvic fracture, Ewing's sarcoma and chemotherapy, brain tumor, nephrotic syndrome, and ulcerative colitis (2, one of whom developed the DVT 3 months before the onset of gastrointestinal symptoms). The sites of thrombophlebitis encountered were left iliofemoral vein, right iliofemoral, right tibial, and left subclavian. Three patients developed pulmonary emboli, which were recurrent in two and required iliac vein ligation or inferior vena cava clipping. Treatment usually consisted of intravenous heparin followed by oral anticoagulants for 3 to 6 months. Two patients received streptokinase with good results. All the patients recovered. With a limited follow-up (6 months to 5 years), we have not seen any postphlebitic sequelae.

Adolescent↗
PubMed1986

Alterations in stromal glycoconjugates in macular corneal dystrophy.

Nine biotinylated lectins were used as histochemical probes to localize the carbohydrates residues of glycoconjugates in normal corneas and in corneas with macular and granular dystrophy. The lectin binding patterns of normal corneas and of corneas with granular dystrophy were indistinguishable from one another, but were distinctly different from those found in corneas with macular dystrophy. Concanavalin A reacted weakly with normal corneal stromal matrix, but stained stromal matrix of corneas with macular dystrophy intensely. Furthermore, unlike the normal corneal matrix, stromal matrix of corneas with macular dystrophy reacted positively with wheat germ agglutinin (WGA), Ricinus communis agglutinin I (RCA-I), Ulex europeus I, Dolichos biflorus, Bandeiraea simplicifolia I, Bandeiraea simplicifolia II, and soybean and peanut lectins. This study demonstrates specific alterations in glycoconjugates which occur in the corneal matrix of patients with macular dystrophy, namely the presence of oligosaccharides with terminal alpha-fucose, beta-galactose, N-acetylglucosamine and N-acetylgalactosamine residues, and oligosaccharide chains with a beta-galactose-N-acetylgalactosamine sequence.

Adult↗
PubMed1986

Intussusception.

Explore the source record for details and available documents.

Child↗
PubMed1985

HLA-DR4 in ankylosing spondylitis with different patterns of joint involvement.

Fifty patients with ankylosing spondylitis (AS) confined to the spine and sacroiliac joints were compared with 50 cases of AS complicated by various patterns of non-axial joint involvement. Radiological and clinical features were evaluated and HLA-DR4 typing was carried out. This antigen was found in 16% of 200 normal individuals in 18% of patients suffering from exclusively axial AS, and in 54% of patients with additional purely peripheral joint involvement (wrist, finger, ankle, toe). The possibility that HLA-DR4 represents a non-specific marker for peripheral arthritis in patients with ankylosing spondylitis is discussed.

Adult↗
PubMed1984

[Ankylosing spondylitis with and without peripheral joint involvement. The significance of HLA-DR4 in the diagnosis, disease risk and pathogenesis].

50 patients with ankylosing spondylitis without any peripheral arthritis are compared with 50 cases of ankylosing spondylitis complicated by arthritis of different kind. Radiological and clinical features were evaluated and assessed. HLA-DR4 typing was carried out. This antigen was found in 16% of 200 normal individuals, in 18% of all patients with ankylosing spondylitis confined to the spinal column, and in 54% of patients with only peripheral arthritis (wrist, finger, ankle, toe joints). The conclusion that HLA-DR4 represents nonspecific evidence for peripheral arthritis in patients with ankylosing spondylitis is discussed.

Adult↗
PubMed1984

The mechanism of inhibition and "reversal" of mitogen-induced lymphocyte activation in a model of purine-nucleoside phosphorylase deficiency.

Purine-nucleoside phosphorylase (PNP) is a purine degradative enzyme that catalyzes the phosphorolysis of (deoxy) inosine or (deoxy) guanosine to their respective bases and (deoxy) ribose 1-phosphate. A severe T-cell immune deficiency syndrome with hypouricemia is associated with impaired PNP function. To study the biochemical basis for this syndrome we created an in vitro model of PNP deficiency in mitogen (phytohemagglutinin)-stimulated normal human peripheral blood lymphocytes using guanosine to competitively inhibit deoxyguanosine phosphorolysis. Guanosine-induced guanine toxicity was reversed by adenine. Under these conditions, deoxyguanosine (5-45 microM) diminished mitogen stimulation to 30% of control while increasing the deoxyguanosine triphosphate pool (dGTP) by over 20-fold. Deoxycytidine reversed deoxyguanosine toxicity with a diminution of dGTP accumulation, but no significant change in the deoxycytidine triphosphate pool. Thymidine reversed the deoxyguanosine toxicity, repleted the thymidine triphosphate (dTTP) pool, and caused an even further increase in the accumulation of dGTP. These data support a model of lymphotoxicity in PNP deficiency based on dGTP accumulation with inhibition of ribonucleotide reductase and depletion of the thymidine triphosphate pool. Thymidine triphosphate depletion is reversed by either deoxycytidine or thymidine; however, the former diminishes dGTP accumulation (probably by competition for phosphorylation) and the latter potentiates dGTP accumulation (probably through feedback augmentation of guanosine diphosphate (GDP) reduction by ribonucleotide reductase secondary to an increased dTTP pool).

Deoxyribonucleosides↗
PubMed1984

The mechanism of inhibition and "reversal" of mitogen-induced lymphocyte activation in a model of adenosine deaminase deficiency.

The biochemical mechanism of lymphocyte dysfunction with adenosine deaminase deficiency has been investigated using cultured phytohemagglutinin stimulated normal peripheral blood lymphocytes and the adenosine deaminase (ADA) inhibitor 2'-deoxycoformycin. The addition of deoxyadenosine to ADA-inhibited (but not to uninhibited) cells generated increased dATP pools (up to 50-fold greater than controls) and depressed the mitogen response. dATP Accumulation was accompanied by depletion of the other three deoxynucleoside triphosphate (dNTP) pools (dTTP, dCTP, and dGTP). Suppression of the mitogen response could be prevented ("reversed") to 90% of control levels by the addition of deoxynucleoside precursors for the depleted dNTPs at the initiation of mitogen stimulation. "Reversal" restored the dTTP and possibly the dGTP pools. Thus the mechanism of toxicity in this model appears to be inhibition of ribonucleotide reductase by massive accumulation of dATP, resulting in starvation for the other three deoxyribonucleoside triphosphates. "Reversibility" of this toxicity by providing sources for the missing three deoxynucleoside triphosphates argues for ribonucleotide reductase inhibition rather than other mechanisms of deoxyadenosine toxicity in this model.

Adenosine↗
PubMed1983

Gold therapy in patients with systemic lupus erythematosus.

Despite a progressively more favorable prognosis in systemic lupus erythematosus (SLE) a need remains for therapeutic agents with greater benefit and less toxicity than corticosteroids and immunosuppressive drugs. Therefore, we treated 16 patients with SLE but without renal diseases with auranofin, a drug with proved efficacy and safety in rheumatoid arthritis. A modest diminution in overall disease activity, as judged by the investigators, and a reduction in maintenance corticosteroid dosage was achieved. However, neither laboratory assessments nor more objective clinical measurements of SLE disease activity disclosed any improvement over baseline. One case each of proteinuria and thrombocytopenia was observed, most likely related to underlying disease and not the drug, suggesting that auranofin may be safe in patients with SLE. A controlled trial, utilizing a broader spectrum of patients with SLE, may be warranted.

Adrenal Cortex Hormones↗