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J Kramer

Publications and source records attributed to J Kramer.

At least 163 records · Page 9Linked to original sources
PubMed1992

Improved time-of-flight MR angiography of the brain with magnetization transfer contrast.

The authors hypothesized that magnetization transfer contrast (MTC) could be used to improve flow contrast in time-of-flight (TOF) magnetic resonance (MR) angiography. Two- and three-dimensional flow-compensated gradient-echo images were obtained with and without MTC. MTC images were obtained by applying low-power radio-frequency (RF) radiation with a frequency offset from the bulk "free" water resonance frequency before the excitation RF pulse. The signal intensity of stationary tissue decreased as the power applied for the MTC pulse was increased. A smaller decrease occurred in venous signal intensity as measured in the superior sagittal sinus, and less change was seen in the arterial signal intensity as measured in the middle cerebral artery. Cerebrospinal fluid showed no MTC effect. The use of MTC improved small-vessel depiction on maximum-intensity projection images. The authors conclude that use of MTC can substantially enhance the quality of TOF MR angiography of the brain.

Adult↗
PubMed1992

Pituitary adenomas: findings of postoperative MR imaging.

Preoperative and postoperative magnetic resonance (MR) images obtained in 25 patients with pituitary macroadenomas (1.1-5.2 cm in diameter) were evaluated to determine normal (physiologic) and abnormal findings after transsphenoidal or subfrontal surgery. With a 1.5-T unit, T1-weighted sagittal and coronal images were obtained before and after administration of gadopentetate dimeglumine. The physiologic changes after surgery included resorption of packing material and sphenoid sinus opacifications, reexpansion of the pituitary gland, and lowering of the optic chiasm. Implanted gelatin foam appeared as an endosellar, circularly enhancing mass that was seen on follow-up studies to have decreased in size. Muscle-and-fat implants appeared as areas of high signal intensity. In 14 patients, residual tumors were found in the suprasellar (n = 4), retrosellar (n = 3), parasellar (n = 8), and/or endosellar (n = 3) space. Residual tumors were differentiated from implant materials by means of location, characteristic signal intensity, and enhancing pattern, which were identical to those of the corresponding preoperative adenoma in 13 cases (93%). Preoperative studies and clinical information are helpful in the evaluation of postoperative MR imaging examinations.

Adenoma↗
PubMed1992

Transaqueductal migration of a neurocysticercus cyst. Case report.

The clearly documented transaqueductal migration of a solitary intraventricular neurocysticercus cyst is described. The cyst was fortuitously demonstrated on magnetic resonance imaging during migration through the aqueduct. The radiological appearance and clinical significance of this condition are discussed.

Adult↗
PubMed1992

MRI of spondylitis.

MRI of proven spondylitis was performed in 39 patients. Acute spondylitis appeared hypointense on T1-weighted and hyperintense on T2-weighted images. Following intravenous administration of Gd-DTPA, enhancement of the marrow and disc was seen. With progressive healing an increasing signal was seen on T1-weighted images. This was caused by the presence of focal fat marrow representing the first sign of therapy response. As healing progressed, the T1-signal increased due to fatty marrow, while the T2-signal decreased as well as the enhancement following Gd-DTPA administration. Therefore, MR imaging can be recommended as the method of choice for early diagnosis of spondylitis and assessment of therapy response.

Adult↗
PubMed1991

Differential regulation of the expression of proteinases/antiproteinases in fibroblasts. Effects of interleukin-1 and platelet-derived growth factor.

We have previously reported that polypeptide growth factors had an anti-inflammatory effect by decreasing the cytokine-enhanced expression of factor B (FB), an activator of the alternative complement pathway, in human fibroblasts. To further characterize the role of cytokines and growth factors in the inflammatory/repair continuum, we have studied the effects of interleukin-1 (IL-1) and platelet-derived growth factor (PDGF) on the expression of metalloproteinases/antiproteinases of the extracellular matrix in cultured human fibroblasts. Co-incubation of IL-1 and PDGF synergistically increased the expression of stromelysin and interstitial collagenase to 23-fold (for both proteins) over background, while PDGF decreased the IL-1-enhanced expression of FB by 82%. PDGF, but not IL-1, alone or in combination, increased the synthesis of tissue inhibitor of metalloproteinases. RNA blot analysis indicated that the changes in protein synthesis were regulated at a pretranslational level. Cycloheximide treatment indicated that the effects of PDGF on the metalloproteinases/antiproteinases were not protein-dependent, in contrast to results obtained for FB. The effect of the three dimeric forms of PDGF (AA, AB, and BB) on the synthesis of metalloproteinases and FB was also analyzed. The effects were qualitatively similar for each of the dimeric forms; however, the BB and AB isoforms had considerably greater effects than PDGF-AA. It has been reported that the PDGF receptors found in human fibroblasts have higher binding affinity for the BB and AB isoforms of the growth factor. The results presented in this paper are in accord with the possibility that differences in the biological activity of the three isoforms of PDGF are due to differences in the number or affinity of the binding sites of the target cells, rather than to different activation pathways of the receptor. Thus, PDGF increased cytokine effects on metalloproteinases, while decreasing cytokine effects or complement activator FB. The net effect of these changes may be to decrease inflammation and enhance remodeling early in repair and to enhance matrix stability later in the repair process.

Blotting, Northern↗
PubMed1991

Evolution of the major histocompatibility complex: molecular cloning of major histocompatibility complex class I from the amphibian Xenopus.

Class I major histocompatibility complex (MHC) cDNA clones have been isolated from an expression library derived from mRNA of an MHC homozygous Xenopus laevis. The nucleotide and predicted amino acid sequences show definite similarity to MHC class I molecules of higher vertebrates. The immunoglobulin-like alpha-3 domain is more similar to the immunoglobulin-like domains of mammalian class II beta chains than to those of mammalian class I molecules, and a tree based on nucleotide sequences of representative MHC genes is presented.

Amino Acid Sequence↗
PubMed1991

MRI in basal ganglia diseases.

76 patients suffering from different basal ganglia diseases (28 cases with M. Parkinson, secondary parkinsonism and Parkinson diseases; 5 cases with Chorea Huntington; 5 cases with Fahr disease and 38 cases with M. Wilson) MRI featured 2 characteristical patterns: 1. abnormal deposition of minerals, 2. focal atrophies of involved organs. Thus MRI provides with informations about: 1. differential diagnosis in clinically misleading courses, 2. stage and, as a consequence, prognosis of some diseases, 3. biochemical processes of diseases in vivo.

Adolescent↗
PubMed1991

A marked drop in the incidence of the null allele of the B gene of the fourth component of complement (C4B*Q0) in elderly subjects: C4B*Q0 as a probable negative selection factor for survival.

The incidence of allotypes of the genes of the fourth component (C4) and factor B of the complement system was compared in 252 persons under 45 years of age ("young" group) with 482 people between 61 and 90 years of age ("old" group). One hundred people older than 90 years of age (nonagenarians) were also investigated. A striking difference was found between the "young" and "old" groups in the incidence (16.1% and 5.4%, respectively) of a silent gene of the C4B allele (C4B*Q0). This difference was even more marked among "young" and "old" men (17.6% vs 3.4%). The incidence of the C4B*Q0 allele in women dropped to the level of the men only in the nonagenarian group. The most probable explanation for this finding is that people carrying the C4B*Q0 allele die from as yet unidentified disease(s) in their middle-age. Therefore, male (and to a lesser extent female) carriers of this allele may have a considerably shorter life expectancy than individuals without a silent gene in the C4B locus.

Adult↗
PubMed1991

Potential markers of the atherosclerotic process in high-risk children.

Children whose parents had early coronary heart disease were investigated. In order to assess high-risk parameters serum total cholesterol (TC), total triglyceride (TT), high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), lipid peroxide (LP), prostacyclin (PGI2), thromboxane (TX) levels, and the distribution of the complement 3 (C3), protein phenotypes were measured. Compared to a group of control children, the offspring of high-risk subjects had increased LDLC, LP, TC, and TX levels, a higher incidence of fast-slow heterozygotes, and decreased HDLC and PGI2 levels. The measurement of serum PGI2, TX levels and the distribution of C3 protein phenotypes may give further information about the true risk of atherosclerosis.

Adolescent↗
PubMed1991

HLA-DR1 is associated with vitiligo.

In Eastern Hungary, vitiligo is found to be associated with HLA-DR1. When other autoimmune disorders are also present, DR3 is also increased.

Autoimmune Diseases↗
PubMed1991

Contrast-enhanced MRI for the staging of bronchogenic carcinoma: comparison with CT and histopathologic staging--preliminary results.

Nineteen patients with potentially operable bronchial carcinoma were included in a prospective study to assess the staging capabilities of plain and contrast-enhanced magnetic resonance imaging (MRI) in comparison with computed tomography (CT) and to compare the results to post-operative histopathological staging (HS). The evaluation focused on the following T-staging criteria: (i) direct invasion of the pleura; (ii) neoplastic invasion of the mediastinum; (iii) differentiation of the primary tumour from alterations of the surrounding lung parenchyma such as inflammation or atelectasis; and (iv) intrathoracic lymph node involvement by tumour. MRI and CT produced similar results for pleural invasion (sensitivity of 0.4 and 0.75 respectively and a specificity of 0.86 and 0.93 respectively). Mediastinal invasion was overdiagnosed in four patients (no false negatives), whereas CT had only one false positive result (two false negatives). Our results showed CT to be superior to MRI for the preoperative evaluation of patients suffering from bronchogenic carcinoma.

Adult↗
PubMed1991

[Sudeck's disease--MRT as a new diagnostic procedure].

In this prospective study, we determined the value of MR as an imaging technique in diagnosis and therapy with the option of simultaneous assessment of bone and soft tissue. 20 patients with clinical diagnosis of reflex sympathetic dystrophy syndrome (RSDS) and positive results in radiogram and three-phase radionuclide bone scanning were examined by MR, using T1- and T2-weighted images before and after Gadolinium-DTPA i.v. Soft tissue and bone signal intensity changes can be classified in our diagnostic-therapeutic scheme and proven by histopathological changes. The differentiation between clinical stages is possible and allows an evaluation of course and therapy. The higher costs are justified by shorter examination time without using radiation.

Adult↗
PubMed1991

Sclerosis multiplex in gypsies.

MS rarely occurs in gypsies in Hungary despite the high DR2 frequency. When it does occur, it has special features more resembling that of Asians than Central Europeans. In order to find correlation between the clinical observations and the immunogenetical data, the distribution of DQw1 subtypes was investigated by means of Eco RV - DQ beta RFLP in DR2 positive healthy gypsies and Hungarians, as well asin DR2-positive Hungarian and unselected gypsy MS patients. DQw6 correlated with MS susceptibility in Hungarians. This allotype was completely absent in healthy DR2-positive gypsies. DR2-positive gypsy MS patients, however, carried DQw6. No correlation of complement allotypes with the occurrence of MS was found in Hungarians, while a striking elevation of C4 Q0 occurred in gypsy MS patients compared with healthy individuals in the gypsy group. The absence of the DR2, DW2, DQw6 haplotype, and the frequency of C4A Q0 in healthy gypsies seems to be associated with the low MS prevalence, but genes outside this region might also influence the MS susceptibility.

Alleles↗
PubMed1991

Synthesis of C1 inhibitor in fibroblasts from patients with type I and type II hereditary angioneurotic edema.

Patients with hereditary angioneurotic edema (HANE) have serum levels of functionally active inhibitor of the first component of complement (C1 INH) between 5 and 30% of normal, instead of the 50% expected from the single normal allele. Increases in rates of catabolism have been documented in patients with HANE and certainly account for some of decrease in C1 INH level. A possible role for a decrease in synthesis of C1 INH in producing serum levels of C1 INH below the expected 50% of normal has not been well studied. We studied the synthesis of C1 INH in skin fibroblast lines, which produce easily detectable amounts of C1 INH. In type I HANE cells, C1 INH synthesis was 19.6 +/- 4.0% (mean +/- SD) of normal, much less than the 50% predicted. In type II HANE cells, the total amount of C1 INH synthesis (functional and dysfunctional) was 98.9 +/- 17% of normal; the functional protein comprised 43% of the total. Thus, type II HANE cells synthesized functional C1 INH at a much greater rate than for the type I cells. In both type I and II HANE cells, amounts of steady-state C1 INH mRNA levels paralleled rates of C1 INH synthesis, indicating that control of C1 INH synthesis occurred at pretranslational levels. Both type I and type II fibroblasts synthesized normal amounts of C1r and C1s. These data suggest that the lower than expected amounts of functionally active C1 INH in type I HANE may be due, in part, to a decrease in rate of synthesis of the protein, and that the expressions of the normal C1 INH allele in HANE is influenced by the type of abnormal allele present.

Adult↗
PubMed1991

Self-defeating personality, self-reinforcement, and depression.

51 men who were more self-defeating were observed to use lower frequency of self-reinforcement and to be more depressed. The results were seen as supporting Beck's early work which proposed a relationship between depression and self-defeating patterns. They also provide construct validity for the measure of Self-defeating Personality used in the study.

Adult↗
PubMed1991

[Diagnosis of cerebrovascular disorders using nuclear magnetic resonance tomography].

Regarding cerebrovascular diseases magnetic resonance imaging (MRI) provides informations which could not be obtained before by any other imaging method. MRI permits an early detection of ischemic infarctions, exact delineation of lesions near to skull base, and microangiopathy. Further diagnosis of arteriovenous malformations and venous thromboses can be done without using contrast media. Exclusion of acute hemorrhage or subarachnoidal hemorrhage is still a domain of computed tomography (CT). Other MR methods, like magnetic resonance angiography (MRA) and magnetic resonance spectroscopy (MRS) are expected to replace angiography and positron emission tomography (PET) in the near future, at least for some purposes.

Adult↗