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Biomedical subjects

I Levy

Publications and source records attributed to I Levy.

At least 37 records · Page 2Linked to original sources
PubMed2001

Expression, refolding and indirect immobilization of horseradish peroxidase (HRP) to cellulose via a phage-selected peptide and cellulose-binding domain (CBD).

We examined the potential immobilization of horseradish peroxidase (HRP) to cellulose with cellulose-binding domain (CBD) as a mediator, using a ligand selected from a phage-displayed random peptide library. A 15-mer random peptide library was panned on cellulose-coated plates covered with CBD in order to find a peptide that binds to CBD in its bound form. The sequence I/LHS, which was found to be an efficient binder of CBD, was fused to a synthetic gene of HRP as an affinity tag. The tagged enzyme (tHRP) was then immobilized on microcrystalline cellulose coated with CBD, thereby demonstrating the indirect immobilization of a protein to cellulose via three amino acids selected by phage display library and CBD.

Amino Acid Sequence↗
PubMed2001

Dual microsporidial infection with Encephalitozoon cuniculi and Enterocytozoon bieneusi in an HIV-positive patient.

This report describes the first dual microsporidial infection with Encephalitozoon cuniculi and Enterocytozoon bieneusi in an HIV-positive patient. In view of clinical and epidemiological findings, our E. cuniculi isolate was deduced to be of the dog strain. The patient's occupational involvement with dogs indicates that canines should be considered as a reservoir of human infections for both microsporidial species. Furthermore, our report provides detailed clinical and radiological information on a rare case of a symptomatic pulmonary infection by E. cuniculi and its improvement after treatment with albendazole.

AIDS-Related Opportunistic Infections↗
PubMed2001

Center-periphery organization of human object areas.

The organizing principles that govern the layout of human object-related areas are largely unknown. Here we propose a new organizing principle in which object representations are arranged according to a central versus peripheral visual field bias. The proposal is based on the finding that building-related regions overlap periphery-biased visual field representations, whereas face-related regions are associated with center-biased representations. Furthermore, the eccentricity maps encompass essentially the entire extent of object-related occipito-temporal cortex, indicating that most object representations are organized with respect to retinal eccentricity. A control experiment ruled out the possibility that the results are due exclusively to unequal feature distribution in these images. We hypothesize that brain regions representing object categories that rely on detailed central scrutiny (such as faces) are more strongly associated with processing of central information, compared to representations of objects that may be recognized by more peripheral information (such as buildings or scenes).

Adult↗
PubMed2001

Resection of hepatocellular carcinoma without preoperative tumor biopsy.

OBJECTIVE: To evaluate the need for a preoperative tumor biopsy of liver lesions suspicious for hepatocellular carcinoma (HCC). SUMMARY BACKGROUND DATA: With advances in liver imaging, the results of recent studies have suggested a very high accuracy of preoperative evaluation of liver masses suspicious of HCC, making preoperative tumor biopsy unnecessary. METHODS: A retrospective analysis was conducted of all liver resections for HCC at the Toronto General and Mt. Sinai Hospitals, Toronto, between October 1994 and December 1998. RESULTS: Sixty patients underwent 65 liver resections without a preoperative liver biopsy. The median age was 61 years. Sixty percent of the patients had cirrhosis and 38.5% had noncirrhotic chronic hepatitis. HCC was confirmed histologically in the surgical specimen in 63 of the 65 cases (96.9%). Both patients without HCC had a significant risk factor for HCC (chronic hepatitis C and alcohol in one and chronic hepatitis B and previous resection for HCC in the other). The lesions were 2 cm and 2.7 cm in diameter, and the alpha-fetoprotein level was low (<5 and 22 ng/mL, respectively). In such patients, with tumor 3 cm or smaller and an alpha-fetoprotein level less than 100 ng/mL (10 patients), the false-positive rate for the preoperative diagnosis was 2/10 (20%). CONCLUSIONS: Preoperative diagnosis of HCC was highly accurate in lesions larger than 3 cm. Tumor biopsy is unnecessary in these patients. However, in a subgroup of patients with lesions less than 3 cm, particularly those with alpha-fetoprotein levels less than 100 ng/mL, there is a higher false-positive diagnostic rate, and tumor biopsy should be considered.

Adult↗
PubMed2001

Mycetoma of the renal pelvis caused by Fusarium species.

A preterm infant, with posterior urethral valves had a mycetoma of the renal pelvis caused by Fusarium species. Prolonged treatment with amphotericin B alone or with flucytosine failed. Combined surgical drainage and medical therapy resulted in full resolution.

Adult↗
PubMed2000

[Transarterial oil chemoembolization for hepatocellular carcinoma, in 100 cases].

Hepatocellular carcinoma (HCC) is a common malignancy with a grave prognosis. Most patients have both the malignant tumor as well as hepatic cirrhosis. Liver transplantation or hepatectomy are considered the only curative procedures, but can be applied in fewer than 10% of patients. In recent decades the most common treatments of HCC are transarterial chemoembolization with oil (TOCE) and percutaneous ethanol injection (PEI). We summarize our retrospective study of 100 patients (mean age 64 +/- 3) treated by TOCE. In 271 procedures between 1989-1998, in 16 patients hepatectomy was combined with TOCE and in 8 PEI was combined with TOCE, while the rest were treated by TOCE alone. Tumor mass was reduced in 36% of those treated by TOCE (tumor volume reduced 24-75%). Alpha-feto protein (AFP) was reduced 25-90% in 20/32 of those with elevated AFP levels. Median survival for the 100 in the entire group was 19 months (10.9 months in those with conservative treatment). Median survival in the 57 in Okuda stage 1 and the 43 in stages 2 or 3 was 30.1 months and 10.9 months, respectively (p < 0.0001). Of the 57 in stage 1, 16 underwent hepatectomy in addition to TOCE and 41 were treated only by TOCE (median survival 15 and 26 months, respectively, p not significant). Comparing Okuda 1 patients treated by TOCE only with the natural history of the disease and historical controls (Okuda 1 patients treated conservatively in 1984) median survival was 26 and 10 months respectively (p < 0.001). The side effects of TOCE were relatively mild. There was 1 fatality (3 days after treatment), and quality of life was maintained. Despite progress in the treatment of HCC by TOCE, PEI, and liver transplantation, long-term survival has remained unsatisfactory.

Aged↗
PubMed2000

Elevated cytosolic phospholipase A(2) expression and activity in human neutrophils during sepsis.

Sepsis is defined as the systemic inflammatory response to infection. Phospholipase A(2) (PLA(2)) plays an important role in inflammation processes by initiating the production of inflammatory mediators. The role of cytosolic PLA (cPLA(2)) has not yet been identified in inflammatory and infectious disease clinical settings. The aim of the present research was to determine whether cPLA(2) activity has a role during sepsis. Since neutrophil activation has been documented during sepsis, these cells were chosen as a model to evaluate the function of cPLA(2) in this clinical setting. cPLA(2 )was studied at 3 levels: activity, protein expression, and messenger RNA (mRNA). Neutrophils from 32 septic patients with and without bacteremia were examined. cPLA(2) activity was measured using labeled phosphatidyl choline vesicles as a substrate, and total PLA(2) was determined by the release of labeled arachidonic acid from prelabeled cells. A significant increase in cPLA(2) activity, protein expression, and total PLA(2) activity in neutrophils was detected during sepsis. mRNA levels, detected by reverse transcriptase-polymerase chain reaction, were significantly higher during sepsis, indicating that the increase in the amount of cPLA(2) is regulated on the mRNA level. The significant elevation of cPLA(2) activity and expression in neutrophils during sepsis suggests that this enzyme plays a major role in neutrophil function in this clinical setting. (Blood. 2000;95:660-665)

Adult↗
PubMed2000

Expression, purification and applications of staphylococcal protein A fused to cellulose-binding domain.

Because staphylococcal Protein A (ProtA) binds specifically to IgG, it has been used for many immunological manipulations, most notably antibody purification and diagnostics. Immobilization is required for most of these applications. Here we describe a genetic-engineering approach to immobilizing ProtA on cellulose, by fusing it to cellulose-binding domain (CBD) derived from the cellulose-binding Protein A of Clostridium cellulovorans. The bifunctional fusion protein was expressed in Escherichia coli, recovered on a cellulose column and purified by elution at alkaline pH. ProtA-CBD was used to purify IgG from rabbit serum and its ability to bind IgG from different sources was determined. The bifunctional chimaeric protein can bind up to 23.4 mg/ml human IgG at a ratio of 1 mol of ProtA-CBD/2 mol of human IgG, and can purify up to 11.6 mg/ml rabbit IgG from a serum. The ability to bind functionally active CBD-affinity reagents to cellulosic microtitre plates was demonstrated. Our results indicate that a combination of CBD-affinity reagents and cellulosic microtitre plates is an attractive diagnostics matrix for the following reasons: (i) cellulose exhibits very low non-specific binding; and (ii) CBD-fusion proteins bind directly to cellulose at high density. A unique signal-amplification method was developed based on the ability of ProtA-CBD to link stained cellulose particles to primary antibody in a Western blot.

Animals↗
PubMed2000

Post-partum reclassification of glucose tolerance in women previously diagnosed with gestational diabetes mellitus.

AIMS: To re-evaluate post-partum screening; fasting plasma glucose (FPG) vs. oral glucose tolerance test (OGTT) in Caucasian women with previous gestational diabetes mellitus (GDM). METHODS: Once breast-feeding had finished, an OGTT was performed in 120 women with previous GDM. They were classified according to World Health Organization (WHO) 1985 and American Diabetes Association (ADA) 1997 criteria. The kappa-statistic measure of agreement was used to compared both diagnostic categories. A receiver-operating characteristic (ROC) curve studied the FPG as a test to detect abnormal glucose tolerance. RESULTS: Identical diabetes prevalence (2%) but quite different intermediate categories (12% impaired glucose tolerance vs. 3% impaired fasting glucose) were observed with both criteria. The kappa-statistic (scaled from 0 to 1) was 0.38 (fair agreement), P = 0.000. The ROC curve area of the FPG was 0.65. CONCLUSIONS: FPG is an unsatisfactory method of evaluating the glucose tolerance of Caucasian women with previous GDM. OGTT may be a better test for such a purpose.

Adult↗
PubMed2000

Gastric outlet obstruction by gallstone: Bouveret syndrome.

Gallstone has rarely been described as a cause of gastrointestinal obstruction. However, the relative incidence of gallstone ileus increases significantly with age. The gastric outlet is very seldom the location of obstruction by a gallstone. The diagnosis of this condition is not difficult. Nevertheless, if treatment is delayed, high morbidity and mortality rates result. Comprehensive treatment aims to relieve the obstruction, to close the biliodigestive fistula and to prevent further gallbladder complications. The surgeon who deals with this type of illness should tailor the treatment plan according to the age, general condition, and intraoperative findings of the individual patient. This paper presents a case report of an 88-year-old woman with gastric outlet obstruction caused by a gallstone.

Aged↗
PubMed1999

Complete recovery after spontaneous drainage of pancreatic abscess into the stomach.

Pancreatic abscess is a dreaded complication of acute pancreatitis, with a high death rate even with aggressive surgical treatment. We report two cases in which recovery followed spontaneous drainage into the stomach. A 75-year-old woman with biliary pancreatitis and a 63-year-old man with ethanol-induced pancreatitis both developed pancreatic abscess, diagnosed by computed tomography scans and ultrasound. The spontaneous gastric fistula was heralded by a large emesis of purulent and necrotic material in one case and copious nasogastric tube secretions of a similar material in the other. Defervescence was immediate, and both patients went on to complete recovery without any further interventions. Contrast studies showed the fistulae. It is concluded that in the event that a pancreatic pseudocyst spontaneously drains into the stomach a 'wait and see' policy should be adopted, and a favorable outcome can be expected.

Abscess↗
PubMed1999

Decreased CGRP, but preserved Trk A immunoreactivity in nerve fibres in inflamed human superficial temporal arteries.

The peptidergic sensory innervation of cranial blood vessels may play an important part in vascular head pain. The neuropeptides calcitonin gene-related peptide (CGRP) and substance P in sensory fibres are dependent on nerve growth factor (NGF) produced by the blood vessels, and when released from nerve terminals mediate neurogenic inflammation. NGF is increased in inflamed tissues, and acts via its high affinity receptor trk A on nociceptor fibres to produce hyperalgesia. CGRP and trk A immunoreactive nerve fibres have therefore been studied, for the first time, in inflamed (n=7) and non-inflamed (n=10) temporal arteries biopsied from patients with headache and suspected giant cell arteritis. CGRP immunoreactivity was markedly decreased to absent in adventitial nerve fibres in inflamed regions of vessels, which may reflect secretion from nerve terminals, as CGRP immunoreactivity could still be seen in nerve trunks in periadventitial tissue. Trk A immunoreactive nerve fibres were found in a similar distribution to CGRP containing nerve fibres in non-inflamed vessels, and the trk A immunoreactivity was virtually unchanged in inflamed vessels. The evidence supports a role for NGF related mechanisms in inflammatory vascular head pain. Anti-NGF or anti-trk A agents may represent novel analgesics in this condition.

Adult↗
PubMed1999

Usefulness of ambulatory blood pressure monitoring in pregnant women with type 1 diabetes.

OBJECTIVE: Pregnancy in type 1 diabetes is associated with an increased risk of developing pregnancy-induced hypertension (PIH). Ambulatory blood pressure monitoring (ABPM) has been used to screen for preeclampsia in nondiabetic pregnancy. To date, there are no data regarding ABPM during pregnancy in normotensive type 1 diabetic women. This study sought to establish blood pressure (BP) profiles for pregnant type 1 diabetic women using ABPM and determine whether the BP pattern can define a population at risk for developing PIH. RESEARCH DESIGN AND METHODS: ABPM was carried out for one 24-h period during each trimester--in the first trimester between weeks 7 and 12, in the second trimester between weeks 20 and 24, and in the third trimester between weeks 30 and 34--in 22 normotensive pregnant type 1 diabetic and 10 pregnant nondiabetic women. RESULTS: The incidence of PIH was fourfold greater in type 1 diabetic women than in control subjects. Diabetic women showed higher daily diastolic BP in the third trimester compared with nondiabetic pregnant women. Diabetic women who developed PIH in the third trimester showed significantly higher BP profiles throughout gestation than those who remained normotensive. Receiver operator characteristics curves for nighttime systolic BP showed the best predictive capacity for PIH, with a cutoff > 105 mmHg (85% sensitivity and 92% specificity). CONCLUSIONS: Our study confirms the early increase of BP in patients who will develop PIH and suggests that nighttime systolic BP >105 mmHg in the second trimester is a useful predictor of PIH. ABPM may be useful in screening for PIH in pregnant diabetic women.

Adolescent↗
PubMed1999

[Non-specific cecal ulcer in a patient with chronic renal failure in hemodialysis treatment. Case report].

We report a 65 years old female undergoing hemodialysis, presenting with intense pain in the lower right quadrant and moderate hematochezia. Since symptoms did not abate after an appendectomy, a colonoscopy and barium enema were performed, whose results suggested an advanced cecal carcinoma. Biopsies were negative for cancer. A new surgical abdominal exploration disclosed a cecal inflammatory and transmural lesion. A right colectomy was performed and the patient had a satisfactory postoperative evolution. Pathological study of the surgical piece showed a six cm perforated profound ulceration and a two cm ulcer. Both had precise limits. Unspecific cecal ulcers are rare entities that must be born in mind in the differential diagnosis of abdominal pain or hematochezia, specially in patients undergoing chronic hemodialysis.

Cecal Diseases↗
PubMed1998

[Effects of vertical banded gastroplasty on weight, quality of life and nutrition].

We examined the long term results of vertical banded gastroplasty 3-10 years after operation. They were assessed by weight lost, incidence and severity of untoward effects and improvement in diet and in quality of life in 75 of 122 who had had the operation. Average weight lost was 28.5 +/- 14.9 kg (p < 0.001) in 5 years and 58.6 +/- 30.4% of excess weight, which brought patients to within 32 +/- 25.2% of ideal weight. According to these measures, in 63-76% the operation had been successful in causing weight loss. The 2 criteria for successful weight loss were loss of more than 50% of weight in excess of ideal body weight and residual body weight less than 50% greater than ideal body weight. There was a greater risk of failure in unmarried subjects older than 45 (odds ratio for not losing weight was 6; in those weighing more than 120 kg it was 9). We saw evidence of this mostly 4 years after operation (odds ratio 11). The degree of success in weight loss was correlated with texture of food (softness) preferred and length of operation. Of those interviewed, only 65% were satisfied with their results. The greatest improvement in quality of life measurements was in physical activity, perception of health, and frequency of feeling depressed. Side-effects were vomiting, reflux and fatigue. Only 34.7% were able to digest solid foods, so that subjects are at risk for nutritional deficiencies.

Adult↗
PubMed1998

Emergence of Candida parapsilosis as the predominant species causing candidemia in children.

An increase in the rate of isolation of Candida parapsilosis, relative to other Candida species, in our children's hospital led us to analyze the clinical and epidemiological variables associated with candidemia. We sought to determine if these variables are different for patients infected with C. parapsilosis. All episodes of candidemia occurring over a 7-year period were analyzed retrospectively. Of 81 episodes in 80 patients, 35 (43%) were in neonates, and 46 (57%) were in nonneonates. C. parapsilosis was isolated in 40 episodes (49%). C. parapsilosis was significantly more likely than non-C. parapsilosis species to be associated with prematurity (P = .001), presence of a central venous catheter (P = .002), and use of total parenteral nutrition (P = .03). C. parapsilosis has emerged as the predominant species in our children's hospital. The mortality rate associated with candidemia in children is lower than previously reported and may be associated with the high rate of isolation of C. parapsilosis.

Adolescent↗