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Biomedical subjects

N Martin

Publications and source records attributed to N Martin.

At least 217 records · Page 12Linked to original sources
PubMed1990

Lymphokine-activated killer (LAK) cells discriminate between Epstein-Barr virus (EBV)-positive Burkitt's lymphoma cells.

We have generated in vitro lymphokine-activated killer (LAK) cells from healthy donors by stimulating their mononuclear leukocytes with recombinant interleukin-2 (rIL-2) (100 U/ml). After 6 days in culture, the lytic properties of the LAK cells were analyzed in the 51Cr-release assay by utilizing a target panel of 6 paired lines consisting of an Epstein-Barr virus (EBV)-positive Burkitt's lymphoma (BL) cell line and an EBV-transformed lymphoblastoid cell line (LCL) from the same donor, the Raji BL line and the natural killer (NK) cell-sensitive K562 line. The patterns of lysis showed that the LAK cells discriminated between two categories of BL cell lines. Group I/II BL tumor cells which expressed the common acute lymphoblastic leukemia antigen (CALLA), the BL-associated glycolipid antigen (BLA) and phenotypically resembled biopsy cells were strongly lysed whereas group III BL cells which had assumed an LCL-like phenotype during culture and lacked the CALLA and BLA surface markers were only poorly lysed. The LCL targets were generally resistant to lysis but the K562 cell line was particularly sensitive. The outcome of cell depletion and monoclonal antibody (MAb) studies indicated that the LAK cell populations were phenotypically and functionally heterogeneous and consisted of at least 2 subpopulations of effector cells; a tumor-specific component and an NK-cell-mediated component.

Animals↗
PubMed1990

Gadolinium-DTPA enhanced MR imaging in tuberous sclerosis.

Ten patients with clinical tuberous sclerosis were examined with CT and MR imaging, before and after IV contrast in order to determine the role of Gd-DTPA. Gd-DTPA enhancement occurred in eleven subependymal nodules which did not enhance on CT after IV contrast. As illustrated by previous CT and pathologic observations and related to the histologic similarity of the subependymal nodules and giant-cell astrocytomas, these hyperintense nodules could represent active lesions with the potential to evolve. Four giant-cell astrocytomas were detected both with CT and Gd-DTPA-enhanced MRI; tumor conspicuity and size assessment were improved by postcontrast MRI in two cases. No cortical tuber or heterotopic cluster enhanced; T2-weighted sequences therefore remain necessary for their detection. If pre and post-Gd-DTPA T1- and T2-weighted imaging is negative, CT is clearly the most sensitive modality in the detection of the small calcified subependymal nodules.

Adolescent↗
PubMed1990

Primary choroid plexus papilloma of the cerebellopontine angle: MR imaging.

The authors report the CT and MR findings of a rare benign primary choroid plexus papilloma developed in the CPA with invasion of the neighboring structures, apparently the first description of such a case. Differential diagnosis with other CPA tumors is discussed. Papillomas should be considered among the vascular, calcified enhancing masses of the CPA even in adulthood.

Aged↗
PubMed1990

Pre-operative micro-angioplasty of refractory vasospasm secondary to subarachnoid hemorrhage.

A patient with subarachnoid hemorrhage secondary to a basilar artery aneurysm developed severe bilateral middle and anterior cerebral artery vasospasm with extensive neurologic deficits. Microangioplasty of the middle cerebral artery segments bilaterally led to reversal of the neurologic deficits, allowing early operative treatment of the aneurysm in a previously inoperable patient.

Aged↗
PubMed1990

Repetition and verbal STM in transcortical sensory aphasia: a case study.

The repetition performance of a patient (S.T.) with transcortical sensory aphasia is examined in four experiments with particular emphasis on the STM capacities underlying her performance. S.T.'s repetition of word strings exceeding her span (two words) is characterized by good recall of the final items and a strong tendency to lose the initial items in the input string. This pattern contrasts with the serial position effects observed in a phonologically based STM impairment, and it is suggested that a lexical-semantic impairment, also evident in S.T.'s naming and lexical comprehension, contributes to her inability to retain the primacy portions of the input string. Lexical effects obtained in her reproduction of words and nonwords, as well as word strings (Experiments 1 and 2), indicate that under conditions of impaired semantics S.T. is relying on lexical phonological information to repeat. Priming by repeated exposure (Experiment 3) failed to improve her repetition performance, indicating that access to lexical information is brief and dependent on recent phonological input. In Experiment 4, the role of syntactic structure in S.T.'s sentence repetition was examined, and it was shown that syntactic structure affects the recall of order information, but not the number of items recalled. The repetition and verbal STM abilities of this patient, in light of her total language profile, are then evaluated in the context of a language-based view of verbal STM.

Aged↗
PubMed1990

Outer membrane proteins of Pseudomonas.

In this review, we describe the outer membrane proteins of Pseudomonas aeruginosa and related strains from the Pseudomonas fluorescens rRNA homology group of the Pseudomonadaceae, with emphasis on the physiological function and biochemical characteristics of these proteins. The use of opr (for outer membrane protein) is proposed as the genetic designation for the P. aeruginosa outer membrane proteins and letters are assigned, in conjunction with this designation, to known outer membrane proteins. Proteins whose primary functions involve pore formation, transport of specific substrates, cell structure determination and membrane stabilization are discussed. The conservation of selected proteins in the above Pseudomonas species is also examined.

Bacterial Outer Membrane Proteins↗
PubMed1990

Comparison of the outer membrane protein and lipopolysaccharide profiles of mucoid and nonmucoid Pseudomonas aeruginosa.

Laboratory-derived mucoid variants of Pseudomonas aeruginosa were selected by plating the standard PAO1 laboratory strain with bacteriophage. These mucoid variants formed two distinct groups of strains on the basis of phage typing. The first group had the same phage-typing pattern as the parent PAO1 strain, while the second group had a distinctly different phage-typing pattern. One strain from each group was assessed along with the parent PAO1 strain for its outer membrane protein (OMP) and lipopolysaccharide (LPS) profiles by sodium dodecyl sulfate-gel electrophoresis followed by appropriate staining. The mucoid derivatives were found to differ from the parent PAO1 nonmucoid strain in having lost a high-molecular-weight LPS species. Furthermore, the reversion of the mucoid strains to the nonmucoid phenotype was accompanied by a return of the missing high-molecular-weight LPS species. No observable difference between the mucoid derivatives and the parent nonmucoid strain was noted in the OMP profiles. The opposite was found in the case of four isolates of mucoid P. aeruginosa from patients with cystic fibrosis. Two OMP bands (of approximately 55 and 25 kilodaltons) were present in the mucoid isolates but missing in their sister nonmucoid strains. In the case of the cystic fibrosis isolates, no difference in the LPS profiles within mucoid-nonmucoid pairs was noted.

Bacterial Outer Membrane Proteins↗
PubMed1990

Chronic inflammatory disease of the middle ear cavities: Gd-DTPA-enhanced MR imaging.

Twenty-seven patients with chronic middle ear infection were prospectively studied with pre- and post-contrast magnetic resonance (MR) images to assess the role of MR imaging in the recognition of middle ear tissue abnormalities. The findings were correlated with computed tomographic (CT) scans and surgical and pathologic data. Granulation tissue constantly appeared enhanced on studies done with gadolinium diethylenetriaminepentaacetic acid (DTPA), unlike cholesteatoma, cholesterol granuloma, or brain herniation into the middle ear cavities. Evaluation of extension and thickness of the inflammatory tissue with MR imaging was in accordance with surgical findings. In six cases, isolated granulation tissue misdiagnosed as either a cholesteatoma or herniated brain on CT scans was accurately evaluated on postcontrast MR images. When granulation tissue was associated with other soft-tissue masses, Gd-DTPA-enhanced MR images allowed accurate definition of the site and the extension of each lesion. Furthermore, abnormal meningeal enhancement was precisely depicted by MR images in two cases.

Adolescent↗
PubMed1990

Differences in epinephrine and substrate responses between arm and leg exercise.

The purpose of this study was to determine epinephrine (EPI) and selected substrate responses during arm crank (AC) and leg cycle (LC) exercise at the same absolute and relative exercise intensity. Nine males performed 30 min AC and LC tests at 70% of ergometer-specific peak oxygen uptake (VO2), and a 30 min LC test eliciting a similar VO2 required during the AC test. Blood samples (30 ml) were collected via an indwelling arm catheter at rest, and at minutes 13 and 28 of exercise for determinations of plasma EPI, serum free fatty acid (FFA), serum glycerol (GLY), blood glucose (GLU), and blood lactate (LA) concentrations. At equivalent VO2, higher (P less than 0.05) EPI, LA, and respiratory exchange ratio (RER) responses were obtained during AC than LC exercise. However, these physiologic responses were similar during AC and LC exercise at the same relative intensity. No significant differences over time were observed for FFA, GLY, and GLU between AC and LC exercise at either the same absolute or relative intensity. The results support previous hypotheses that AC exercise is physiologically more stressful than LC exercise at the same VO2. The data further indicate that adrenomedullary activity (EPI response) and substrate utilization (LA and RER responses) are regulated by relative exercise intensity and not the exercising muscle mass.

Adult↗
PubMed1990

Petrous carotid-to-intradural carotid saphenous vein graft for intracavernous giant aneurysm, tumor, and occlusive cerebrovascular disease.

In the management of cavernous sinus aneurysms, cavernous sinus tumor, and cavernous internal carotid artery (ICA) stenosis, a direct arterial bypass around the pathology may be required. A series of 18 patients is presented in whom a petrous ICA to subarachnoid ICA saphenous vein bypass procedure was performed. The advantages of a short large-caliber venous graft entirely within the skull account for the high patency rate (17 of 18 patients) in this series. This vascular bypass can be recommended in the management of patients whose intracavernous ICA must be sacrificed.

Adult↗
PubMed1990

Carcinoma of the nasopharynx in Chiang Mai University Hospital: a review of 205 cases.

Carcinoma of the nasopharynx is one of the common head and neck cancers in Southeast Asia. We had studied 205 cases of nasopharyngeal cancer who attended the ENT clinic of the Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand from 1980-1984. The majority of the patients were found in stage IV. One hundred and five patients received a curative dose of radiation therapy. The observed actuarial 5 year survival was 34 per cent. There was a significant decrease in survival of patients with T4 disease. Differences in age, sex, histopathology and N-stage did not affect the survival. So far, the only specific treatment we can offer patients is radiation therapy, so an earlier diagnosis must be established in order to get better results of treatment.

Adolescent↗
PubMed1989

Diagnosis of adult linear IgA dermatosis by immunoelectronmicroscopy in 16 patients with linear IgA deposits.

Homogeneous linear IgA deposits at the dermo-epidermal junction (DEJ) shown by direct immunofluorescence are characteristic of what is termed linear IgA bullous dermatosis. However, it is not yet certain that this disease constitutes an entity distinct from other subepidermal blistering diseases, especially when IgG deposits are also present. Sixty-one cases of subepidermal blistering disease in adults were therefore investigated by immunoelectron microscopy (IEM), and the 16 patients observed to have homogeneous linear IgA deposits were compared with the 45 who had no IgA but had IgG and/or C3. In 11 of the 16 patients with IgA (four of whom also had IgG), the deposits were linear and formed a mirror image pattern on each side of the lamina densa from which they were separated by a clear space. In contrast to this monomorphic IEM pattern, clinical and other laboratory findings were very heterogeneous, making exact clinical diagnosis difficult. Of the remaining five patients in this group of sixteen, three (all with both IgA and IgG) had bullous pemphigoid, epidermolysis bullosa acquisita, and cicatricial pemphigoid, respectively, on IEM and clinical investigation. In the remaining two patients (one with both IgA and IgG, and one with IgA only) the deposits were located in the lamina lucida, making precise classification impossible. None of the 45 patients with isolated IgG and/or C3 deposition displayed the mirror image pattern. We conclude that this IEM pattern may constitute a specific diagnostic criterion of linear IgA dermatosis.

Adult↗
PubMed1989

Cholesterol granulomas of the middle ear cavities: MR imaging.

Symptomatic cholesterol granuloma developed in the middle ear cavities in three cases. At computed tomography (CT) after the administration of contrast material, the granulomas appeared as nonspecific, nonenhanced soft-tissue masses with variable bone erosion. These features are indistinguishable from those of other similar clinical entities, especially cholesteatoma, paraganglioma, and endaural brain hernia. At magnetic resonance (MR) imaging, cholesterol granulomas had a more characteristic appearance. In two cases, the granulomas were depicted as areas of high signal intensity with both T1- and T2-weighted sequences. In the third case, an expansile mastoid cholesterol cyst exhibited medium signal intensity on T1-weighted images, with only a small hyperintense area and a hypointense area located in the cystic wall. Correlations between CT, MR, and microscopic findings show that MR imaging is far superior to CT in tumoral characterization, which is crucial for planning surgical approaches. MR imaging has limitations, however, particularly its inability to depict subtle bone abnormalities.

Adult↗
PubMed1989

[Cranial pachymeningitis of unknown origin. Study of 3 cases].

The clinical picture in three cases of chronic cranial pachymeningitis of unknown origin was dominated by headache, disturbed balance, a confusional state and cranial nerve lesions. The erythrocyte sedimentation rate was increased and the CSF showed inflammatory changes. CT scan imaging showed thickening of the tentorium cerebelli, which took up contrast intensely. Meningeal biopsy showed the dura-mater to be the site of a non-specific inflammatory process. No precise cause was found. Clinical manifestations in these three patients were remarkably corticosensitive but lesions did not regress on CT. The development of a state of corticodependence led to an attempt at treatment with radiotherapy and/or azathioprine, but follow up is insufficient to evaluate results.

Adult↗