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Biomedical subjects

M Lema

Publications and source records attributed to M Lema.

At least 55 records · Page 3Linked to original sources
PubMed1991

Protein C and S levels in acute leukemia.

Patients with acute leukemia undergoing remission induction chemotherapy occasionally develop venous thrombosis despite severe thrombocytopenia and in the absence of disseminated intravascular coagulation. This observation prompted us to study the levels of the naturally occurring anticoagulant proteins C and S prospectively in patients undergoing remission induction chemotherapy for acute leukemia. Plasma samples from 50 adult patients with acute leukemia (34 AML, 16 ALL) were analyzed for protein C antigen, functional protein C, immunologic total and free protein S as well as levels of C4b binding protein (C4bBP). Plasma levels of immunologic protein C were significantly lower in patients with active acute myelocytic leukemia (mean = 77.9) than in controls (mean = 123.6) or patients in remission (mean = 132). Functional protein C levels were also significantly lower in AML patients with active disease (mean = 58.5) than controls (mean = 95.5) or patients in remission (mean = 98.5). Patients with acute lymphocytic leukemia (ALL) had normal levels of immunologic and functional protein C. Although total protein S levels were normal in all patients studied, levels of free protein S were significantly decreased in patients with active AML (mean = 29.3) compared with patients in remission (mean = 42.0) or controls (mean = 42.4). In contrast, patients with ALL, both with active disease and in remission had normal free protein S levels. This decrease in free protein S seen in active AML was not associated with liver disease, white cell count or an increase in C4bBP. These findings provide a possible explanation for the occasional occurrence of venous thrombosis in patients with acute myelocytic leukemia.

Acute Disease↗
PubMed1991

Bone anomalies in myotonic dystrophy.

Sixteen patients with myotonic dystrophy underwent CT examination of the skull, and measurement of bone mineral density at lumbar spine and hip by dual-photon absortiometry. The results were compared with those of 20 normal subjects of similar age and sex distribution. Hyperostosis of the calvarium, and increased bone mineral density at lumbar vertebrae were observed. One case showed basal ganglia calcification associated with hyperparathyroidism secondary to deficiency of vitamin D. In the other 15 patients, studies of calcium metabolism were normal. There results suggest the existence of generalized hyperostotic potential in patients with myotonic dystrophy.

Adolescent↗
PubMed1991

[Platelets and migraine. Correlation between biochemical markers of platelet aggregation and serotonin].

The correlation between the biochemical markers of platelet activation and serotonin in migraine was investigated. The beta-thromboglobulin (beta-TG), platelet factor 4 (PF-4) and serotonin levels in 105 patients with migraine were measured. The results confirmed an increase in beta-TG and PF4 levels and a reduction in serotonin levels during the migraine attacks. However, we did not find a significant correlation between these fluctuations. These findings suggest the existence of extraplatelet mechanism in the pathophysiology of migraine.

Adolescent↗
PubMed1990

[Hormonal profile and changes in platelet aggregation in menstrual migraine].

We evaluated the hormonal profile and the platelet function in a group of 20 patients with menstrual migraine and a control group of 10 healthy women. Plasma levels of estradiol, progesterone, FSH and LH, as well as betathromboglobulin, platelet factor 4 and platelet serotonin were measured in different phases of the menstrual cycle. The hormonal profile did not show significant differences between both groups. The patients with menstrual migraine had higher BTG, FP4 and serotonin levels in the premenstrual phase than the control group. The results of this study show that in premenstrual migraine a platelet hyperagregation develops during the premenstrual phase. This abnormality is not directly correlated with the hormonal fluctuations observed during the menstrual cycle.

Adult↗
PubMed1990

[Platelet function in tension headache].

The possibility of abnormal platelet function in patients with tension headache was evaluated with serial plasmatic measurements of serotonin, beta-thromboglobulin and platelet factor 4. In 40 patients with tension headache we found increased serotonin, thromboglobulin and platelet factor 4 levels during the painful phases as compared with the asymptomatic phases. These data might indicate that an increased platelet aggregation plays some role in the pathogenesis of tension headache.

Adult↗
PubMed1989

[Magnetic resonance in the evaluation of neurologic complications of cervical spondylosis].

The evaluation of the neurological complications of cervical spondylosis frequently requires contrast myelography. Magnetic resonance (MR) scan would appear as a good alternative approach. We report the MR findings in 12 patients with symptoms and/or signs of spinal cord and radicular disease associated with cervical spondylosis, and we compare them with the conventional studies, including CT and CT assisted myelography. The MR image, weighted in T1, permitted to visualize the compressed spinal cord in the sagittal planes in 4 cases, with enhanced spinal cord signal in 2 of them. In a patient with herniated C5-C6 disk, the sagittal sections directly demonstrated the herniated material in the spinal canal, displacing and compressing the spinal cord. The sequences weighted in T2 demonstrated the degree of stenosis of the cervical canal caused by extradural compression. In these images, the diminished signal of the nucleus pulposus was correlated with degeneration of intervertebral disks. MR was more sensitive than the other studies to detect discal degeneration and herniation, stenosis of the spinal canal, compression of the subarachnoidal space and spinal cord injury.

Aged↗
PubMed1984

Plasmid transfer into members of the family Legionellaceae.

The plasmids RP4 and pPH1JI::Mu::Tn5 were transferred with moderate frequency from Escherichia coli to Legionella pneumophila (strain Bloomington 2) and Fluoribacter (Legionella) bozemanae (strain WIGA). The frequency of transfer to Tatlockia (Legionella) micdadei (strain Tatlock) was much lower. In these transconjugant strains the plasmids were maintained following at least 10 nonselective passages. However, the introduced plasmids could not be transferred from these strains to several other strains of Legionella or Tatlockia with a detectable frequency, yet they could be transferred to a restriction-modification deficient (rm-) E. coli strain with moderate frequency. This suggests not only that the expression of transfer genes may be repressed but that the legionellae are poorer recipients than are the rm- E. coli.

Bacteria↗
PubMed1984

Capillary gas chromatographic analysis of carbohydrates of Legionella pneumophila and other members of the family Legionellaceae.

Legionella pneumophila, the causative agent of Legionnaires disease, and related organisms have previously been characterized primarily by conventional bacteriological methods, DNA-DNA hybridization, antigenic analysis, and fatty acid analysis. By capillary gas chromatographic analysis for carbohydrates, we have shown that muramic acid and glucosamine, characteristic markers of bacterial cell walls, were present in samples of L. pneumophila and a group of legionella-like organisms. Some bacterial samples contained two unusual isomeric aminodideoxyhexoses (X1 and X2). L. pneumophila was characterized by the absence of fucose and the presence of the peak X1. Tatlockia micdadei (Legionella micdadei) was distinguishable by the presence of large amounts of rhamnose and fucose and by the absence of X1 and X2. Fluoribacter strains were much more variable in their carbohydrate composition. These data suggest that, in addition to other reported techniques, carbohydrate profiling by capillary gas chromatography can be a valuable diagnostic method in reference microbiology laboratories for differentiating members of the family Legionellaceae.

Carbohydrates↗
PubMed1983

Electrophoretic characterization of soluble protein extracts of Legionella pneumophila and other members of the family Legionellaceae.

The soluble peptides of strains of Legionella pneumophila, Tatlockia micdadei, Fluoribacter bozemanae, Fluoribacter dumoffii, and Fluoribacter gormanii were studied by polyacrylamide gel electrophoresis. Characteristic patterns were seen for Legionella and Tatlockia strains, whereas the patterns for the Fluoribacter strains were variable as would be expected for this genetically heterogeneous group. Grouping by peptide pattern was consistent with proposed taxons based on DNA-DNA homology. By using a new silver stain technique, the sensitivity and ease of pattern recognition were enhanced significantly. This technique is an easily applied general method for distinguishing between strains in epidemiological studies.

Bacteria↗
PubMed1982

Plasmid and surface antigen markers of endemic and epidemic Legionella pneumophila strains.

Environmental and clinical isolates of Legionella pneumophila obtained from the Pittsburgh Veterans Administration Medical Center were studied for the presence of plasmids and for unique surface antigens. The majority of environmental isolates contained a single 80-megadalton plasmid. After an epidemic of nosocomial Legionnaires disease subsided in the Spring of 1981, plasmid-bearing environmental isolates persisted in the environment. Whereas L. pneumophila could not be reisolated from most sites with plasmidless isolates. During this epidemic the attack rate was highest on wards with plasmidless isolates. All clinical isolates were plasmidless. Strains were serotyped by the indirect immunofluorescence method with serum from a single immunized rat which was used both without absorption and after absorption with various plasmid-bearing and plasmidless isolates. These studies suggested that a plasmid-associated surface antigen was present and that the most common plasmidless environmental serotype was similar to the epidemic clinical serotype.

Antigens, Bacterial↗