Search PubMed⌕ Search

Biomedical subjects

R Adar

Publications and source records attributed to R Adar.

At least 55 records · Page 3Linked to original sources
PubMed1992

Expression of Erythrina corallodendron lectin in Escherichia coli.

The cDNA of the Erythrina corallodendron lectin (ECorL) has been expressed in Escherichia coli. For this purpose, an NcoI site was inserted into the cDNA coding for the lectin precursor [Arango, R., Rozenblatt, S. & Sharon, N. (1990) FEBS Lett. 264, 109-112] immediately before the codon GTG (103-105) which codes for the N-terminal valine of the mature lectin. This introduced an ATG codon for a methionine preceding the valine. The mutated cDNA was ligated into pUC-8, then subcloned into the expression vector pET-3d, which carries a strong promoter derived from gene 10 of the phage T7. The recombinant plasmid was introduced into the E. coli lysogenic strain BL21(DE3). Recombinant ECorL was expressed by growing the bacteria in the presence of isopropyl beta-D-thiogalactopyranoside. Most of the recombinant lectin was found in an insoluble aggregated form as inclusion bodies and only a small part was in the culture medium in a soluble active form. Functional recombinant lectin was recovered from the inclusion bodies by solubilization with 6 M urea in cyclohexylaminopropane sulfonate pH 10.5, renaturation by 10-fold dilution in the same buffer and further adjustment of the pH to 8.0. The recombinant lectin, obtained at a yield of 4-7 mg/l culture, had, by gel filtration, a slightly lower molecular mass (56 kDa) than the native lectin, and was devoid of covalently linked carbohydrate; it was, however, essentially indistinguishable from native ECorL by other criteria, including its dimeric structure, Western blot analysis with anti-ECorL polyclonal and monoclonal antibodies, and Ouchterlony double-diffusion analysis with polyclonal antibodies, as well as hemagglutinating activity and specificity for mono- or disaccharides.

Amino Acid Sequence↗
PubMed1992

Laser Doppler flowmetry in lower extremity ischemia: application and interpretation.

The present study was undertaken in order to develop numerical criteria for the parameters of laser Doppler flowmetry-skin blood flow velocity and pulse wave amplitude in the evaluation of lower extremity ischemia. Fifty limbs of young healthy volunteers were examined in order to obtain baseline normal values. Patient population was divided into moderately ischemic (52 limbs) and severely ischemic (22 limbs), based on patients' complaints, physical examination, ankle-brachial indices, pulse volume recordings and arteriographies. Univariate comparison between the three groups of skin blood flow velocity and pulse wave amplitude at each time point were done by analysis of variance. Power of discrimination between degrees of ischemia was evaluated by computing sensitivity and specificity, based on skin blood flow velocity and pulse wave amplitude values at time points best for predicting the severity of disease by multiple regression analysis. Using cutoff points of < 31 for skin blood flow velocity and < 9 for pulse wave amplitude, a 96% sensitivity and 96% specificity were obtained in separating normal from ischemic limbs. Cutoff points of < 9 for skin blood flow velocity and < 4 for pulse wave amplitude discriminated with a 100% sensitivity and specificity between the moderately and severely ischemic limbs. We propose the use of laser Doppler flowmetry with local heating and reactive hyperemia, and the cutoff points stated above as an additional tool to evaluate lower extremity ischemia through assessment of cutaneous microcirculation.

Adult↗
PubMed1992

Autoimmune mechanisms in thromboangiitis obliterans (Buerger's disease): the role of tobacco antigen and the major histocompatibility complex.

This study is a continuation of our previous work that showed that patients with thromboangiitis obliterans (TAO; Buerger's disease) demonstrate a cell-mediated immune response to human artery type-specific collagens. To investigate the role of cigarette smoking in patients with TAO, cellular and humoral sensitivity was tested to a tobacco glycoprotein (TGP) antigen in 13 patients with Buerger's disease, 16 healthy smokers, and 12 nonsmoking healthy young male subjects. In this study, patients with Buerger's disease and healthy smokers had the same rate of cellular response to TGP, whereas nonsmokers did not respond. All three groups had a 30% to 40% measurable antibody response to TGP. If TGP has an immunologic role in the pathogenesis of TAO, an additional factor (or factors) may be operative. A specific genetic makeup may be one such factor, although at this stage other pathogenic mechanisms cannot be ruled out. Eleven patients with Buerger's disease and two control groups of 10 young healthy smoking male subjects and 12 young nonsmokers underwent histocompatibility leukocyte antigen (HLA) typing. Patients with Buerger's disease had a statistically significantly higher frequency of HLA-DR4 and a significantly lower frequency of the HLA-DRW6 antigen than had both control groups. Because similar findings have been reported in other autoimmune diseases, this observation may serve as further evidence that an autoimmune mechanism is involved in Buerger's disease.

Antibody Formation↗
PubMed1991

Changes in plasmatic tissue-type plasminogen activator and plasminogen activator inhibitor activity during acute arterial occlusion associated with severe ischemia.

Severe lower limb ischemia in patients with acute arterial occlusion was associated with a significant increase in systemic fibrinolytic activity. Plasmatic level of t-PA activity was twice the normal value at the peak of ischemia. This level declined gradually within no less than 40 hours after reperfusion procedure or limb amputation had reverted the ischemic state. In spite of major tissue damage and surgical trauma, plasmatic PAI activity stayed within normal range, and did not increase within the first 24 hours postoperatively. These findings strongly suggest that acute ischemia initiates systemic induction of excessive and continuous release of t-PA, which outweighs any anticipated increase in PAI activity.

Arterial Occlusive Diseases↗
PubMed1991

[Surgery for thoraco-abdominal aortic aneurysm].

12 patients underwent resection of a thoraco-abdominal aortic aneurysm. There were 10 men and 2 women, ranging in age from 54-78 years (mean 65). Aortic arteriosclerosis was the primary etiology in 11, and Behcet's disease in the other 1. Most patients (7/12) presented with Type 3 aneurysm, extending from the distal descending thoracic aorta to the distal abdominal aorta; none had aortic dissection. 11 were operated on for symptoms related to the aneurysm: 3 of these had a contained rupture. The risk factors were chronic obstructive pulmonary disease in 10, hypertension (10), diffuse arteriosclerosis (8), ischemic heart disease (6), chronic renal failure (5) and cerebrovascular accident (1). The surgical technique in 11 was graft inclusion and visceral vessel reattachment. The main complication was acute renal failure, seen in 3 patients. None had spinal ischemia. Operative mortality was 33%. Of the 4 who died, 2 had myocardial infarction and 2 uncontrolled intraoperative bleeding. According to the literature the major complications are spinal cord ischemia and renal failure.

Acute Kidney Injury↗
PubMed1991

Vascular insufficiency quantitatively aggravates diabetic neuropathy.

The effect of lower-limb ischemia on the severity of neuropathy was examined in 48 diabetic patients with peripheral vascular disease. The severity of the vascular disease, as determined by medical history, physical findings, and laboratory data, was scored for each leg. Neuropathy was rated clinically and based on the results of nerve conduction studies of the common peroneal, posterior tibial, and sural nerves. A significant correlation was found between the vascular scores and neurologic variables of the two legs, most strikingly so in electrophysiologic data, with coefficients of .6 to .7. Nondiabetic control patients showed no evidence of neuropathy, regardless of the severity of ischemia, whereas diabetic controls without limb ischemia showed symmetrical neuropathy. These findings support the hypoxic theory in the pathogenesis of diabetic neuropathy.

Adult↗
PubMed1991

Pulse volume recording disturbances in paraplegic patients.

Spinal cord injuries may modify vascular reactivity in the denervated region. This study presents an original observation of altered vascular response in paraplegic patients. A group of 30 consecutive paraplegic otherwise normal individuals underwent a thorough vascular examination. There were 29 male and 1 female patient, 21 to 67 years old (average 41), all with traumatic spinal cord injury. Average time since injury was 17 years. All had good peripheral pulses and normal segmental Doppler pressure measurements. In 8 patients, plethysmography--pulse volume recording (PVR) was normal as expected. In 22 patients an unusual feature of the vascular examination was recorded, consisting of normal peripheral arterial pressures with PVR waveforms indicating poor pulsatility. This group was older than the group with normal studies: ages 44 +/- 13 vs 34 +/- 8 years (p = 0.05), and more time had elapsed since injury-20 +/- 12 vs 10 +/- 4 years (p = 0.015). The altered pulsatility demonstrated in most of those paraplegic patients may play a role in deficient wound healing frequently observed below the level of spinal neurological loss.

Adult↗
PubMed1991

Biochemical analysis of a human humoral fibroblast inhibitory factor associated with impaired vascular prosthetic graft incorporation.

A specific inhibitory factor was isolated from human serum of a patient who manifested impaired prosthetic graft tissue incorporation. The latter reaction was hypothesized to be related to inhibiting fibroblast proliferation by a specific humoral factor. The crude inhibitory serum was tested against a pool of normal human sera with different cell types in culture. Proliferation of human skin fibroblast and human smooth muscle cell cultures incubated in the presence of 50% inhibitory serum were inhibited up to 58% and 37%, respectively. Proliferation of bovine capillary endothelial cell cultures was stimulated under similar conditions. Isolation and purification of the inhibitory factor from crude serum were initiated by ammonium sulfate precipitation. The pellet was further fractionated by sepharose 6B gel filtration. The inhibitory activity was eluted from the column in a relatively purified form as indicated by gel electrophoresis of the inhibitory fractions, which demonstrated a specific band corresponding to the inhibitory protein, with an apparent relative molecular mass of 230 kDa. The inhibitory factor showed a high affinity to concanavalin A, indicating its nature as a glycoprotein not associated with albumin or immunoglobulin fractions of the serum.

Aged↗
PubMed1990

Echocardiography in diagnostic assessment of peripheral arterial embolization.

In an attempt to identify a cardiac source of emboli, two-dimensional echocardiography was performed postoperatively in 42 consecutive patients with acute peripheral arterial embolism requiring urgent embolectomy. The patients were divided into four groups. Group 1 included 14 patients with chronic atrial fibrillation, among whom four cases of intracavitary thrombi were detected. Group 2 included 13 patients with acute or previous myocardial infarction, and left ventricular thrombi were detected in three. Group 3 included one patient with a prosthetic mechanical aortic valve and one with mitral valve prolapse; thrombi were not detected in either. Group 4 comprised 13 patients with no clinical evidence of a cardiac source of embolism; in one of them a large left ventricular thrombus was detected. Altogether eight intracavitary thrombi were detected (19%), and only in three (7.1%) were the results of echocardiographic examinations defined as entirely normal. A number of clinically undetected cardiac lesions, such as mitral annular calcification and aortic valve calcification, possibly associated with peripheral arterial embolism, were also detected by postoperative echocardiography. Because of the high percentage of intracavitary thrombi detected and the therapeutic implications thereof, especially if embolism recurred, it is concluded that two-dimensional echocardiographic examination should be recommended for patients with acute peripheral embolism.

Aged↗
PubMed1989

Type I procollagen C-proteinase from mouse fibroblasts. Purification and demonstration of a 55-kDa enhancer glycoprotein.

The enzyme procollagen C-proteinase removes the carboxy-terminal propeptide from procollagen. In the present study we describe an improved procedure for the purification of this enzyme. From the medium of cultured mouse fibroblasts, consisting of ammonium sulfate precipitation, gel filtration and affinity chromatography on a lysyl-Sepharose column, followed by chromatography on a column of Sepharose coupled to the carboxy-terminal propeptide of type I procollagen (PP-Sepharose). This procedure yielded a practically homogeneous, 18,500-fold-purified enzyme preparation and the molecular mass of the purified C-proteinase as determined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis was 80 kDa. The lysyl-Sepharose step separated the enzyme from the majority of the contaminating proteins, including a 55-kDa protein which was further purified by PP-Sepharose chromatography and identified as an additional form of the 36-kDa and 34-kDa procollagen C-proteinase enhancer proteins described before [Adar et al. (1986) Collagen Relat. Res. 6,267-277]. It enhanced the C-proteinase activity, bound to the carboxyl propeptide of type I procollagen, cross-reacted immunologically with the 36-kDa as well as the 34-kDa enhancer proteins, and in common with the latter proteins, it was glycosylated. In the course of PP-Sepharose chromatography, a large proportion of the 55-kDa protein disappeared with the concomitant appearance of the smaller enhancer proteins. All these findings suggest that the 55-kDa protein is a precursor of the low molecular mass enhancer proteins. Also suggested from this study is that lysyl-Sepharose chromatography is a highly beneficial purification step which may find use in the purification of the C-proteinase from other sources as well.

Animals↗
PubMed1989

The amino acid sequence of Erythrina corallodendron lectin and its homology with other legume lectins.

The primary sequence of Erythrina corallodendron lectin was deduced from analysis of the peptides derived from the lectin by digestion with trypsin, chymotrypsin, Staphylococcus aureus V8 protease, elastase and lysylendopeptidase-C, and of fragments generated by cleavage of the lectin with dilute formic acid in 6 M guanidine hydrochloride. Purification of the individual peptides was achieved by gel filtration, followed by reverse phase HPLC. The glycosylation site (Asn17-Leu18-Thr19) was deduced from analysis of the glycopeptide isolated from a pronase digest of the lectin before and after deglycosylation of the glycopeptide with endoglycosidase F. Comparison of the sequence of 244 residues thus obtained with those of 9 other legume lectins revealed extensive homologies, including 39 invariant positions and 60 partial identities. These data provide further evidence for the conservation of the lectin gene in leguminous plants.

Amino Acid Sequence↗
PubMed1989

[Occlusive arterial disease after radiation].

A 50-year-old man was treated for occlusion of the superficial femoral artery which had developed 6 years after X-ray therapy to the thigh for a malignant tumor. Occlusive arterial disease is more common after doses of more than 4000 rad and appears more frequently within the first 10 years after doses of 5000 rad or more. Clinical and experimental data suggest that X-radiation predisposes to atherosclerotic change by causing endothelial damage. The clinical approach to symptomatic occlusive disease of arteries that traverse irradiated fields is similar to treatment of other atherosclerotic lesions, except that in some instances an extra-anatomic route should be considered if bypass is required.

Arterial Occlusive Diseases↗
PubMed1989

[Carotid endarterectomy].

Carotid endarterectomy was performed 77 times in 73 symptomatic patients. In 67 of them there had been 1 or more transient ischemic attacks (TIA), in 4 transient atypical symptoms, and in 2 mild persistent neurological deficits. After operation 1 died of a stroke and 1 had a nonfatal myocardial infarction. In 3.3% of 33 low-risk patients (Sundt's classes 1 and 2) there was mild postoperative neurological deficit. The rate of neurological complications was much higher in 40 high-risk patients (classes 2 and 3), including 5 with postoperative stroke. Followup averaged 21.5 months (longest 54 months), the 5-year survival (by extrapolation from a life table analysis curve) was 87%, and there was only 1 fatal stroke. Those who recovered from operation without complications had an 86% chance of having no further neurological problems.

Carotid Arteries↗