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Biomedical subjects

J Ge

Publications and source records attributed to J Ge.

At least 199 records · Page 11Linked to original sources
PubMed1993

A cytotoxic human hybridoma monoclonal antibody (TrJ5) specific for HLA-B38(16) and -B39(16).

We have generated a cytotoxic IgM lambda human hybridoma mAb (TrJ5), that is specific for HLA-B38(16) and -B39(16). Among a panel of 42 HLA-defined cell lines, TrJ5 killed all five B38-positive and both B16-positive cell lines, as well as the single B39-positive cell line, but not any cell lines lacking these antigens. It could be ruled out that the TrJ5 epitope is located on the alpha 1 domain because TrJ5 did not react with cells bearing HLA-B14, the alpha 1 domain of which is identical to alpha 1 of B39. In the alpha 2 domain of B38 and B39, a unique threonine residue at position 158 (Thr-158) is not shared by any of 29 other HLA-B alleles. This suggests that Thr-158 of the alpha 2-domain helix is critical for the TrJ5 epitope.

Antibodies, Monoclonal↗
PubMed1993

Coronary artery remodeling in atherosclerotic disease: an intravascular ultrasonic study in vivo.

BACKGROUND: Pathologic studies have revealed that coronary arteries undergo compensatory enlargement in the presence of atherosclerosis. METHODS: In order to assess coronary artery remodeling in vivo, we used intravascular ultrasound to examine 46 patients (36 men and 10 women; aged 58.2 +/- 6.8 years) with non-calcified plaques. The vessel, lumen, and plaque areas of the atherosclerotic and of normal proximal and distal segments were determined. RESULTS: A total of 92 atherosclerotic segments were analyzed. The degree of stenosis ranged from 9.2 to 92.8% (mean 34.1 +/- 16.9%) and the plaque area from 2 to 19.6 mm2 (mean 6.3 +/- 3.6 mm2). The vessel area of the atherosclerotic segment (mean 20.4 +/- 7.3 mm2) was larger than that of the proximal segment (mean 18.7 +/- 7.3 mm2, P = 0.018). The vessel area increased in proportion to plaque area. This relationship can be described using the equation y = 23.5(1-e-0.35x). The difference between the vessel area in the atherosclerotic segment and that in the proximal normal segment correlated with the percentage of stenosis (r = 0.53, P < 0.005) until the degree of stenosis exceeded 45%. CONCLUSION: This study indicates that coronary artery remodeling, previously observed in pathologic studies, can be evaluated using intravascular ultrasound in vivo. As a result of the compensatory enlargement of the vessel, coronary angiography cannot be used to detect or exclude the early signs of coronary atherosclerosis.

Adult↗
PubMed1993

A human monoclonal hybridoma antibody (TrJ1) specific for HLA-DQ2.

TrJ1 is a cytotoxic human hybridoma mAb (IgM lambda). Its reaction pattern with a panel of 42 HLA-defined lymphoblastoid B-cell lines correlated precisely with expression of DQ2. By flow cytometry it was shown that the binding of TrJ1 to DQ2 was efficiently blocked by the murine anti-DQ2 mAb 358.4, indicating that the TrJ1 and 358.4 epitopes overlap. TrJ1 reacted much better with EBV-transformed B cells than with B cells freshly isolated from blood. TrJ1 seemed suitable for typing freshly isolated B cells provided the incubation with complement lasted for 115 min in Terasaki plates. One or more of the DQ2-specific polymorphic amino acids E46, F47, L52, L55, K71 or A74, situated on the alpha-helix of the DQ2 beta chain, are probably critical for the TrJ1 epitope.

Antibodies, Monoclonal↗
PubMed1993

The profiles of interaction of yohimbine with anxiolytic and putative anxiolytic agents to modify 5-HT release in the frontal cortex of freely-moving rats.

1. The interaction of yohimbine with anxiolytic and putative anxiolytic agents to modify 5-hydroxytryptamine (5-HT) release in the frontal cortex of the freely-moving rat was assessed using the microdialysis technique. 2. The alpha 2-adrenoceptor antagonist, yohimbine (5.0 mg kg-1, i.p.) increased maximally the extracellular levels of 5-HT in the rat frontal cortex by approximately 230% of the basal levels. 3. The alpha 2-adrenoceptor agonist, clonidine (30-100 micrograms kg-1, i.p.) decreased dose-dependently the extracellular levels of 5-HT in the rat frontal cortex by approximately 0-60% of the basal levels. A 5 min pretreatment with clonidine (50 micrograms kg-1, i.p.) prevented the yohimbine-induced increase in the extracellular 5-HT levels. 4. The benzodiazepine receptor agonist, diazepam (2.5 mg kg-1, i.p.) and the 5-HT3 receptor antagonist, ondansetron (100 micrograms kg-1, i.p.) (5 min pretreatment) completely prevented the yohimbine (5.0 mg kg-1, i.p.)-induced increases in the extracellular levels of 5-HT. The 5-HT1A receptor agonist, 8-OH-DPAT (0.32 mg kg-1, s.c.) partially antagonized the yohimbine response. 5. A 5 min pretreatment with the 5-HT3/5-HT4 receptor ligand R(+)-zacopride (10 micrograms kg-1, i.p.) reversed the yohimbine (5.0 mg kg-1, i.p.)-induced increase in the extracellular levels of 5-HT to approximately 30% below the basal levels. A 5 min pretreatment with S(-)-zacopride (100 micrograms kg-1, i.p.) failed to modify the response to yohimbine. 6. The present study provides evidence of the ability of the anxiogenic agent, yohimbine, to increase the activity of the central 5-hydroxytryptaminergic system and the ability of clonidine and various anxiolytic and putative anxiolytic agents to prevent the yohimbine response.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1993

The study of relationships between the damage of visual function and hemorrheology, ocular rheography, as well as other related factors in patients with primary open angle glaucoma (POAG).

Researches of glaucoma visual function damage, hemorheology, ocular rheography and other related multiplex factors, with computed multifactorial stepwise regression analysis, indicate that the elevation of intraocular pressure (IOP) is not the only factor to induce visual impairment. POAG patients are shown to have markedly reduced diastolic perfusion pressure in ophthalmic artery, besides prolonged filling time of the retinal artery and vein, diminished erythrocyte deformability and increased platelet adhesion rate. The characteristic of ocular rheographic changes in POAG patients of controlled IOP suggest that the abnormal changes of hemorheology be responsible for the damage of visual function. The abnormal changes of plasma viscosity, blood apparent viscosity, blood viscoelasticity, hematocrit, mean red cell volume etc could be found in addition to the reduction of PO2, SO2% and trace elements (Cr, Zn, Mg, Fe) in patients with POAG. Computed multiply stepwise regression analysis and Bayes discrimination were made among the deteriorate rate of quantitative visual field and 28 factors from the combined investigation. Only the hemorrheological index could be introduced into the multiply regression equations. The more the damage of visual function in POAG patients, the more accurate the discriminatory effect. Based upon the results, and the reports of articles published as well as the search of 1982-1989 Compact Combridge MEDLINE Medical data base, the new clinical concept could be presented that POAG might belong to the scope of blood hyperviscosity syndromes. When IOP elevation and the decrease of ocular artery pressure existed, the damage of visual function in POAG patients should be deteriorated.

Adult↗
PubMed1992

Classification of morphologic effects of percutaneous transluminal coronary angioplasty assessed by intravascular ultrasound.

The aim of this study was the assessment and classification of the morphologic effects of percutaneous transluminal angioplasty (PTCA) by intravascular ultrasound (IU). Fifty-eight patients were examined immediately after PTCA with a 4.8Fr, 20 MHz rotational tip IU system. In 10 patients (17%), IU images could not be analyzed due to failure of the imaging system or poor image quality. In 48 patients (83%; 40 men and 8 women, aged 55 +/- 9 years), IU images of 48 PTCA segments, as well as 41 distal and 44 proximal sites, were analyzed. The left anterior descending artery was studied in 30 patients, the right coronary artery in 17 and the left main coronary artery in 1. Calcium was present in 32 of 48 PTCA segments (67%). Plaque morphology was concentric in 18 patients (38%) and eccentric in 30 (62%). Seven distinct morphologic patterns were observed. In concentric plaques, plaque compression without significant wall alterations (type 1) was found in 2 patients (4%), superficial tears within the plaque (type 2) in 1 (2%) and deep tears (type 3) in 8 (17%). Deep tearing associated with submedial or subintimal dissection (type 4) was found in 2 patients (4%). Dissection between plaque and vessel wall without noticeable intimal tearing (type 5) was the most common morphology (n = 15; 31%) and occurred in concentric and eccentric plaques. In eccentric plaques, no significant tearing of the plaque (type 6) was found in 6 patients (13%), and tearing of the plaque close to its base with dissection (type 7) in 14 (29%).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1992

The interaction of R(+)- and S(-)-zacopride with PCPA to modify rodent aversive behaviour.

The interaction of R(+)- and S(-)zacopride (0.00001-10 mg/kg i.p.) with parachlorophenylalanine (PCPA, 3 day treatment 100 mg/kg i.p.) to modify behaviour in an aversive situation was investigated in the mouse black and white test box and rat social interaction test. R(+)-Zacopride (but not S(-)zacopride) and PCPA had an anxiolytic profile of action to reduce aversive responding in both species. Their established anxiolytic profiles were abolished by a subsequent treatment with S(-)zacopride. In contrast, S(-)-zacopride was less or ineffective if administered simultaneously with R(+)-zacopride. A co-treatment of PCPA with R(+)-zacopride also inhibited the anxiolytic profiles observed to the individual treatments. It is concluded that there is a complex interaction between the isomers of zacopride to modify responding to an aversive situation that is dependent on the temporal sequence of drug administration, and which may be modified by changes in basal 5-hydroxytryptamine (5-HT) tone and agonist, partial agonist and antagonist effects at the 5-HT3 receptor.

Animals↗
PubMed1992

Profiles of interaction of R(+)/S(-)-zacopride and anxiolytic agents in a mouse model.

The mouse black and white test box was used to measure changes in behaviour in an aversive situation where the administration of R(+)-zacopride (but not S(-)-zacopride) alone decreased aversive responding to the white area. A similar anxiolytic profile of action was observed using parachlorophenylalanine (PCPA), whose effects were antagonised by a co-treatment with R(+)-zacopride and reversed by S(-)-zacopride to an exacerbation of the aversive response. An anxiolytic profile of action was also observed using ondansetron, granisetron, chlordiazepoxide, diazepam, ritanserin, 8-OH-DPAT (8-hydroxy-2-(di-n-propylamino)tetralin), E4424 (2-[4-[4-(4-chloro-l-pyrazoyl)butyl]-l-piperazinyl]-pyrimidine), umepsirone, DuP753 (2-n-butyl-4-chloro-5-hydroxy-methyl-1-[2(1H-tetrazol-5-yl) biphenyl-4-yl)methyl)]-imidazole), SQ29,852 ((S)-1-[6-amino-2[hydroxy)(4-phenyl-butyl)phosphinyl]-oxy)-1- nexy]-2-proline), devazepide and guanfacine, and this was retained following co-treatment with PCPA. The anxiolytic profile of action of PCPA was also retained following co-treatment with renzapride which when administered alone failed to modify behaviour. However, the ability of chlordiazepoxide, diazepam, ondansetron and E4424 (but not devazepide, DuP753 or SQ29,852) to reduce aversive responding was inhibited by co-treatment with R(+) and/or S(-)-zacopride. It is concluded that the reduction in aversive responding caused by pharmacological manipulation at the benzodiazepine, 5-HT receptor subtypes 5-HT1A, 5-HT1C/5-HT2 and 5-HT3 (but not at the cholecystokin CCKA or angiotensin receptors or inhibition of angiotensin converting enzyme) can be inhibited by R(+) and S(-)-zacopride. The data is discussed in terms of zacopride having an agonist or partial agonist effect at the 5-HT3 receptor.

Animals↗
PubMed1992

A cytotoxic monoclonal human hybridoma antibody (TrJ3) against HLA-B44(12) and -B45(12).

We have generated a human monoclonal cytotoxic IgM lambda antibody (TrJ3) that reacted specifically with all lymphoblastoid B-cell lines expressing HLA-B44(12) and B45(12). TrJ3 hybridoma supernatant was suitable for HLA-B12 typing of freshly isolated blood mononuclear cells. Analysis of available amino acid sequences of HLA-B molecules indicated that the alpha 1 domain does not contain the TrJ3 serological epitope. Since HLA-B44 is associated with a unique serine residue at position 167 that points towards the peptide binding groove, we propose that S167 of the alpha 2 domain helix is a critical part of the TrJ3 epitope.

Amino Acid Sequence↗
PubMed1992

Differential modulation of extracellular levels of 5-hydroxytryptamine in the rat frontal cortex by (R)- and (S)-zacopride.

1. The ability of various anxiolytic and potential anxiolytic agents to modify 5-hydroxytryptamine (5-HT) release in the frontal cortex of the rat was assessed by the microdialysis technique. 2. The benzodiazepine receptor agonist, diazepam (2.5 mg kg-1, i.p.), the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.32 mg kg-1, s.c.) and the 5-HT1A receptor partial agonist buspirone (4.0 mg kg-1, i.p.) maximally reduced extracellular levels of 5-HT in the rat frontal cortex by approximately 50-60%, 70-80% and 30-40%, respectively. 3. (R)-zacopride (1.0-100 micrograms kg-1, i.p.) dose-dependently reduced extracellular levels of 5-HT in the rat frontal cortex (approximately 80% maximal reduction) whereas the other 5-HT3 receptor antagonists ondansetron (10 micrograms kg-1, i.p.) and (S)-zacopride (10-100 micrograms kg-1, i.p.) were ineffective. 4. In contrast to (S)-zacopride (100 nM; administered via the microdialysis probe), (R)-zacopride (1.0-100 nM; administered via the microdialysis probe) induced a concentration-dependent reduction in extracellular levels of 5-HT in the rat frontal cortex (approximately 70% maximal reduction). 5. In contrast to ondansetron (100 micrograms kg-1, i.p.), (S)-zacopride (10-100 micrograms kg-1, i.p.) dose-dependently reversed the (R)-zacopride (10 micrograms kg-1, i.p.) induced reduction in extracellular levels of 5-HT in the rat frontal cortex. The highest dose of (S)-zacopride (100 micrograms kg-1, i.p.) completely prevented the (R)-zacopride response.In addition, (S)-zacopride (100 nM; administered via the microdialysis probe) attenuated the inhibitory action of (R)-zacopride (10 nM; administered via the microdialysis probe) on extracellular levels of 5-HT in the rat frontal cortex.6. In conclusion, the present study provides further evidence of the ability of diazepam, 8-OH-DPAT and buspirone to reduce the activity of the central 5-hydroxytryptaminergic system in vivo. Furthermore,the results indicate that the ability of (R)-zacopride to reduce the in vivo release of 5-HT in the rat frontal cortex does not correlate with its 5-HT3 receptor antagonism. However, the differential affinity of (R)- and (S)-zacopride for a (S)-zacopride-insensitive (R)-zacopride site in rat cerebral cortex mirrors the relative activity of the two zacopride stereoisomers to modify the in vivo release of 5-HT in the frontal cortex of the rat and their ability to release suppressed behaviour in animal models of anxiety.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1992

Intravascular ultrasound imaging of arterial wall architecture.

Intravascular ultrasound (IVUS) is a promising new technique for assessing vascular morphology and structure. Controversy exists whether the three-layer appearance of the arterial wall correctly reflects the histologic structures of the intima, media, and adventitia. We performed an experimental study to clarify the three-layer appearance. The vessel wall architecture was analyzed by IVUS on eight different kinds of plastic cylinders, 24 normal blood vessels from pigs, and 59 human arterial segments. A distinct three-layer appearance was observed on all the plastic cylinders when the ultrasound beam was perpendicular to the wall. A three-layer appearance was also seen in the arterial wall, in the muscular (iliac, femoral artery) and elastic types (aorta), when the echo beam was perpendicular to the vessel wall. The three-layer pattern was even observed on the arterial wall when the intima was removed. Furthermore, the removed intima itself provided a three-layer image. Histologic examination showed that there was no correspondence between the IVUS three-layer appearance and the intima, media, and adventitia. Moreover, we also performed IVUS on nine patients who suffered from aortic dissection. Intravascular ultrasonic visualization of the dissected intima showed a distinct three-layer pattern. The pattern disappeared when: (1) the echo beam was not perpendicular to the vessel wall; (2) there was connective tissue around the vessel wall; (3) there was arterial wall calcification; or (4) the vessel wall was too thick or the distance between the ultrasound transducer and the vessel wall was too large.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Dissection following balloon angioplasty of aortic coarctation: review of the literature.

Balloon angioplasty of the coarctation of the aorta can result in intimal or medial or even adventitial dissections as demonstrated by in vitro studies and animal experiments. As a typical sign of stretching of the aortic wall, patients complain of pain during the angioplasty procedure. In the literature, aortic wall rupture and ventricular fibrillation during the procedure are reported. Additional sudden deaths can occur within 40 hours after the procedure. Mortality ranges from 0.1% to 2.5%. By transesophageal echocardiography, monitoring of balloon angioplasty, control of the positioning of the balloon, and control of the results and detection of complications are possible. Intimal as well as medial dissections can be detected with observed healing for intimal but also medial dissections. In order to avoid the patient's discomfort, intraaortic ultrasound will be used in the future, when major methodological improvements are done. Computed tomography demonstrates medial dissections but is not able to visualize intimal dissections. Using computed tomography and magnetic resonance after angioplasty of the coarctation of the aorta, irregularities are described in up to 17% of the patients. For angiography, a low detection rate of medial dissections has to be expected, when not biplane angiographies of the whole thoracic aorta are performed. Medial dissections can be seen, but intimal dissections are missed. In conclusion, a review of the literature demonstrates a high incidence of intimal and medial dissections after angioplasty of the coarctation of the aorta with spontaneous healing in most patients. As is the way with coronary angioplasty, aortic wall ruptures are rare, but stand-by surgery is necessary.

Aortic Dissection↗
PubMed1992

[Visual function damage in primary open angle glaucoma (POAG) in relation to hemorheology, ocular rheograph and other factors].

Researches of glaucomatous visual damage, hemorheology, ocular rheograph and other multiplex factors, with computed multifactorial stepwise regression analysis, indicate that elevation of intraocular pressure (IOP) is not the only factor to induce visual impairment. POAG patients are shown to have markedly reduced diastolic perfusion pressure in the ophthalmic artery, besides prolonged filling time of the retinal artery and vein, diminished erythrocyte deformability and increased platelet adhesion rate. The characteristic ocular rheographic changes in POAG patients of controlled IOP suggest that hemorheological factors play a role in the visual function damage.

Adult↗
PubMed1992

[The hemorheological features and other related factors in patients with primary open angle glaucoma (POAG)].

The second part of the investigation revealed that POAG patients manifested abnormalities in plasma viscosity, whole blood apparent viscosity and viscoelasticity, hematocrit, and mean red cell volume, with concurrent reduction in oxygen partial pressure degree of oxygen saturation, and levels of trace elements Cr, Zn, Mg, and Fe. The hemorheological factors should be taken into account in addition to intraocular pressure in the development of visual damages.

Adult↗
PubMed1992

[An analysis of the causes of glaucomatous visual function damage by computed multifactorial stepwise regression].

Computed multifactorial stepwise regression analysis of quantitative visual field deterioration in relation to 28 factors showed that only the hemorheological indices entered the multiplex regression equations, especially accurately for POAG patients with severe visual damages. Besides, the patients might also have lower antioxidant capability in the red cell membrane protein. Based on the present results and data abroad, POAG might pertain to the blood hyperviscosity syndrome, and with elevated intraocular pressure and decreased ocular arterial pressure, the visual function damage would be aggravated.

Blood Viscosity↗
PubMed1992

[Intravascular ultrasound in patients with suspected aortic dissection: comparison with transesophageal echocardiography].

Thirteen patients with suspected aortic dissection (two women, 11 men, age 61 +/- 10.8 years) underwent transesophageal echocardiography (TEE), intravascular ultrasound (IVUS), angiography, and in part computed tomography (CT). TEE was performed using 3.5 or 3.75 MHz ultrasound transducers. IVUS examination was done using a 6F 20 MHz "rotational-tip" IVUS catheter (Boston Scientific) advanced over a guiding-wire positioned in the ascending aorta by the "side-saddle" technique. In two patients it was not possible to advance the catheter into the abdominal aorta. Of the remaining 11 patients, eight had aortic dissection (six Typ III, one Typ II, and one Typ I, de Bakey classification). Two patients had aortic aneurysms without dissection and one patient had a perforation of the ascending aorta. TEE, CT, and angiography led to the correct diagnosis in all patients, while IVUS failed to provide precise information within the ascending aorta and the aortic arch. Reasons were the limited scanfield of the 20 MHz transducer and the inability to steer and position the IVUS catheter. Contrary to the limited value in the ascending aorta, IVUS could successfully scan the entire descending aorta, including the dissection membrane and the originating vessels, if the max. diameter was less than 4 cm. No adverse effects occurred. Intravascular ultrasound allows to scan the entire aorta in patients with suspected aortic dissection. The current limitations can be solved only by the introduction of steerable and/or low frequency catheters.

Aged↗
PubMed1992

[The correlation between measurements performed by intravascular echography and quantitative digital angiography in large- and small-caliber arteries].

Intravascular ultrasound is a new promising technique that appears as a very useful complement to standard angiography in the study of atherosclerosis. Specifically, intravascular ultrasound provides by itself, information of great value concerning vessel wall characteristics. Nevertheless, before taking any decision with the results provided by this new technique, we must validate this information with that provided by other more conventional techniques like standard angiography. Accordingly, we have analyzed in 25 patients, 50 images of the abdominal aorta and 77 images of the coronary arteries taken from arterial segments free of atherosclerotic involvement. With the use of a calibrated small grid located over the patient's thorax, we have analyzed "in the same points" the images obtained with intravascular ultrasound and those provided by contrast angiography using a quantitative angiographic analysis. In the abdominal aorta the vessel diameter measured by intravascular ultrasound and angiography was 17.8 +/- 0.39 mm vs 18.6 +/- 0.42 mm (NS), whereas in the coronary arteries it was 2.76 +/- 0.39 mm vs 2.98 +/- 0.37 mm (NS), respectively. The correlation between both techniques was good for both types of arteries (r = 0.93 in the abdominal aorta and r = 0.87 in the coronary arteries). We conclude, that in our experience and with the methodology used, there is a good correlation between the measurements of the vessel diameters obtained by both intravascular ultrasound and digital angiography in arteries of different sizes, being the correlation even better in large arteries.

Adult↗