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Biomedical subjects

A Martin

Publications and source records attributed to A Martin.

At least 667 records · Page 37Linked to original sources
PubMed1987

Purification and separation of two soluble fucosyltransferase activities of small intestinal mucosa.

1. Rat small intestinal soluble fucosyltransferase is purified more than 2000-fold using chromatographic procedures with DEAE-cellulose, CM-cellulose, GDP-Sepharose and Concanavalin A-Sepharose. 2. Chromatography on Sephadex G15 of the final enzymatic fraction clearly separates two activities: a first peak incorporates fucose on asialoserotransferrin and a second peak on asialofetuin. 3. The use of small saccharidic acceptors (phenylgalactose, lactose, lacto-N-fucopentaose I) and the analysis of fucosylated asialoglycoproteins indicate that the first activity corresponds to an alpha-(3/4)-fucosyltransferase and the second one to an alpha-(1-2)-fucosyltransferase. 4. Protein analysis by polyacrylamide gel electrophoresis in the presence of SDS for each enzyme shows two bands corresponding to a mol. wt of about 65,000 and 70,000. The two enzymes have the same sensitivity to the action of N-ethylmaleimide.

Animals↗
PubMed1987

Studies on zoapatle. V. Correlation between in vitro uterine and in vivo pregnancy interruption effects in guinea pigs.

The zoapatle plant, Montanoa tomentosa, has an extensive ethnomedical history of use in fertility regulation. Several fractions and isolates of this plant were evaulated in in vitro and in vivo tests to identify and characterize active constituents which may be responsible for its antifertility effects. The guinea pig was the animal model. Two types of in vitro activity were observed, a uterotonic type effect and an inhibition of spontaneous contractions of the uterine muscle. The in vivo effects appear to correlate with the ability of a fraction/isolate to inhibit the spontaneous contractions in in vitro testing. The non-polar fractions/isolates accounted for the inhibition of spontaneous contraction effects and the in vivo activity. The more polar fractions/isolates accounted for the uterine stimulant activity.

Abortifacient Agents↗
PubMed1987

Lyme disease in Canada with possible transmission by an insect.

The first documented case of Lyme disease to have originated in Canada is presented. A 51-year old French female nurse visited Quebec, Canada from 20 July to 5 August, 1984 and contracted Lyme disease. She reported an insect bite on 3 August 1984 on the back of her knee with erythema chronicum migrans appearing at the site of the bite on 5 August 1984. The patient presented with meningeal lymphocytic reaction near the end of September, 1984. Total Ig serum titers in indirect immunofluorescence tests on 1 October 1984, 10 October 1984, and 10 January 1985 were 1/512, 1/2048 and 1/16,384, respectively.

Animals↗
PubMed1987

The kidney and cardiovascular system in obstructive jaundice: functional and metabolic studies in conscious rats.

1. The effects of jaundice on renal and circulatory function were investigated in chronic bile duct ligated (CBDL) rats 6 days after surgery. Sham operated (SO) animals served as controls. 2. Body weight was significantly reduced, whereas blood pressure remained unaltered, 6 days after bile duct ligation when serum bilirubin had risen to 169 +/- 18 (SEM) as compared with 2.8 +/- 0.3 mumol/l in SO rats. When compared with control values before surgery, urinary volume had significantly increased and absolute excretion of sodium, potassium, chloride and phosphate had decreased on day 6 after CBDL. Endogenous creatinine clearance was markedly depressed when compared with SO rats. Whereas fractional excretion of potassium remained unaltered, fractional excretion of sodium and of phosphate was significantly increased. 3. Except for a significant increase in urinary thromboxane B2 (TXB2) excretion in CBDL rats, no significant changes were observed in urinary excretion of prostaglandin (PG) E2, in the synthesis of PGE2, 6-keto-PGF1 alpha and TXB2 by isolated aortic tissue in vitro, nor in renal and cardiac adenosine triphosphatase activities or renal cortical mitochondrial function. 4. The adenosine triphosphate content of kidney cortex and cardiac mitochondrial function were significantly depressed in CBDL rats. 5. The results demonstrate that jaundice in CBDL rats is associated with functional and metabolic disturbances of the kidney and cardiac muscle, which may contribute to the renal and haemodynamic characteristics observed in jaundiced animals and humans.

Adenosine Triphosphate↗
PubMed1987

Representation of semantic and spatial knowledge in Alzheimer's patients: implications for models of preserved learning in amnesia.

Patients with Alzheimer's disease may exhibit severe, but variable patterns of cognitive deficits which can complicate and confound investigations of memory. Three patients are described with comparable levels of intellectual and memory abilities as assessed by the Wechsler scales. One patient (W) had a relatively circumscribed impairment of word-finding ability concurrent with intact visuospatial and constructional skill. Another patient (C) showed the opposite profile of abilities, while the third patient (G) exhibited deficits in both domains. All three patients were severely and globally amnesic when tested with traditional recall and recognition procedures. Patient W was able to demonstrate preserved semantic knowledge on a superordinate and category level but not for specific object attributes. Patient C demonstrated a remarkably preserved ability to generate and copy complex, meaningful, but not meaningless material. Corresponding profiles of preserved learning were revealed, but only under conditions that limited the demands on encoding and retrieval processes. Models were offered to account for these contrasting patterns of impairment. In addition, the possibility that medial temporal structures contribute to the ability to consciously reconstruct prior experiences was discussed.

Alzheimer Disease↗
PubMed1987

Seminiferous tubule involution in elderly men.

The observation of different types of seminiferous tubules (from tubules with normal spermatogenesis to sclerosed tubules) in aging human testes points to the progressive stages of tubular involution in elderly men. The tubules with hypospermatogonesis (reduced number of elongated spermatids) show numerous morphological anomalies in the germ cells, including multinucleated cells. Abnormal germ cells degenerate, causing Steroli cell vacuolation. These vacuoles correspond to dilations of the extracellular spaces resulting from the premature exfoliation of germ cells. Degenerating cells that are phagocytized by Sertoli cells lead to an accumulation of lipid droplets in the Sertoli cell cytoplasm. The loss of germ cells begins with spermatids, but progressively affects the preceding germ cell types, and tubules with maturation arrested at the level of spermatocytes or spermatogonia are observed. Simultaneously, an enlargement of the tunica propria occurs. This leads to the formation of sclerosed tubules, some of which display a low seminiferous epithelium consisting of a few cells--including lipid-loaded Sertoli cells and both Ap and Ad spermatogonia--and others, showing complete sclerosis, are devoid of seminiferous epithelium. The development of tubular involution is similar to that reported after experimental ischemia, which also seems to cause nonspecific effects on the testis such as multinucleate cells, vacuoles, and increased lipids in Sertoli cells.

Adult↗
PubMed1987

MHC class II restricted self-recognition after allostimulation: clonal analysis.

After allostimulation in vitro using a combination of HLA-A, B, C, DR, DQ, D identical but HLA-DP different homozygous typing cells, 34 T cell clones were derived. Thirty-one of them were alloreactive clones, but three clones were found to be autoreactive. One of these autoreactive clones was further expanded. In order to characterize in more detail the determinant restricting the autologous response, a panel of HLA-typed peripheral blood mononuclear cells (PBMC) or Epstein-Barr virus lymphoblastoid cell lines (EVB-LCL) was typed. A good correlation of typing responses with the self haplotype HLA-A1, B8, Cw7, DR3, DRw52, DQw2 was found. Typing responses also segregated together with this haplotype in informative families. Blocking studies using MHC class I and II specific monoclonal antibodies (MoAb) linked the restricting determinant to MHC class II molecules. The clone which was both autoproliferative and autocytotoxic bore the CD3(+), CD4(+), CD8(-), Ia(+) phenotype. Antibiotics or foreign plasma proteins were ruled out as restricted determinants.

Antibodies, Monoclonal↗
PubMed1987

Haemoptysis: a case report with tetralogy of Fallot with absent pulmonary valve leaflets and anomalous origin of left pulmonary artery.

A 6 month old female child with tetralogy of Fallot with absent pulmonary valve leaflets and anomalous origin of left pulmonary artery was admitted to hospital with a mild adenoviral lower respiratory tract infection. She had a large haemoptysis 1 week after admission, and recovered with simple supportive measures. This case illustrates a previously unreported complication of a rare anomaly.

Female↗
PubMed1987

Synthaderm in the management of pre-tibial lacerations: a controlled clinical study.

A clinical study of patients with pre-tibial lacerations at King's College Hospital and Guy's Hospital, London, England, compared a non-adhesive dressing with Synthaderm. Treatment was randomly allocated. At King's College Hospital, deep and superficial lacerations were equally distributed, the median time to healing with Synthaderm was significantly (P less than 0.02) reduced; and the median rate of healing (mm/day) was significantly (P less than 0.01) better. At Guy's Hospital, larger and wider wounds were unequally distributed, with fewer in the control group; in the Synthaderm group, the median rate of healing was increased. In both centres, the clinical impression was that Synthaderm reduced nursing dressing time and a better scar resulted. Synthaderm improved the rate of healing in pre-tibial lacerations.

Adolescent↗
PubMed1987

Developmental changes in intestinal glycosyl-transferase activities.

The carbohydrate composition of some intestinal glycoproteins has been demonstrated previously to be modified during development. To evaluate the role of the enzymatic mechanisms of glycosylation, the activities of three soluble and microsomal glycosyl-transferases were studied during postnatal development in rat intestinal mucosa. Nonexistent as soluble forms in the cell sap from suckling rats, the membrane-bound N-acetylgalactosaminyl-, sialyl-, and fucosyl-transferases showed different activities in microsomal fractions before weaning. The N-acetylgalactosaminyl-transferase activity was constant whereas the sialyl-transferase activity, which was maintained at a rather high level until the age of 2 wk, decreased just before weaning, while the fucosyl-transferase activity declined progressively from birth to weaning. After weaning, the three enzymatic activities progressively enhanced until adult age. Their variable behaviors on several glycoprotein acceptors may suggest the presence of several sialyl--and fucosyl-transferases with differences in specificities, varying in different ways according to age. Such developmental modifications in intestinal glycosylation patterns may be linked with certain transformation observed in the carbohydrate level of mucus or membrane-bound glycoproteins and related to the profound modifications in nutritional status at the weaning period.

Animals↗
PubMed1987

Clinical trials in hairy cell leukemia. Current status and future directions.

During the past 5 years, clinical trials in hairy cell leukemia have shown dramatic activity for alpha-interferon and 2'-deoxycoformycin (pentostatin). Responses can be induced in more than 80% of patients using either agent, although a greater number of complete pathologic remissions may be achieved with deoxycoformycin. Despite interesting preliminary data, the optimal dose, schedule, treatment duration, and impact of therapy on survival are unknown. Clinical trials comparing efficacy and toxicity of alpha-interferon and deoxycoformycin, the extent of cross-resistance, and relationship of activity to previous splenectomy are in progress. Additional studies are testing combinations of these agents. Although interferon is commercially available for treating hairy cell leukemia, considering such therapy routine is counterproductive. Long-term clinical trials of interferon and deoxycoformycin are essential to advance our biologic knowledge of this rare disease, and to ensure optimal therapy for a potentially curable malignancy.

Antineoplastic Agents↗