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Biomedical subjects

E Levy

Publications and source records attributed to E Levy.

At least 379 records · Page 21Linked to original sources
PubMedDate not supplied

beta-Amyloid precursor protein gene in squirrel monkeys with cerebral amyloid angiopathy.

Senescent nonhuman primates frequently develop cerebral beta-amyloidosis; for reasons that are not yet understood, the primary histological locus of beta-amyloid deposition varies in different species. In aged rhesus monkeys (Macaca mulatta), fibrillar (congophilic) beta-amyloid (A beta) occurs most frequently in senile plaques, whereas in aged squirrel monkeys (Saimiri sciureus) the cerebral blood vessels are most affected. To determine if cerebral beta-amyloid angiopathy (CAA) in squirrel monkeys is related to a species-specific amino acid change in A beta, as was shown in two hereditary human forms of CAA, the beta-amyloid precursor protein (beta PP) cDNA was sequenced. The predicted amino acid sequence of A beta in squirrel monkeys is identical to that in normal humans. Overall, beta PP751 in the squirrel monkey differs from the human sequence only by four amino acids near the N-terminus and in the KPI domain. These findings suggest that other factors most likely predispose aged squirrel monkeys to cerebral amyloid angiopathy. We propose the squirrel monkey as a useful model for studying the factors contributing to human CAA, and for testing diagnostic and therapeutic approaches to this disorder.

Amyloid beta-Protein Precursor↗
PubMedDate not supplied

Primate-like amyloid-beta sequence but no cerebral amyloidosis in aged tree shrews.

A central pathological feature of Alzheimer's disease is the profuse deposition of amyloid-beta protein (Abeta) in the brain parenchyma and vessel walls. Abeta also forms deposits in the brains of a variety of mammals, including all aged non-human primates studied to date. The sequence of Abeta in these animals is identical to that in humans. No Abeta deposits have been found in the brains of wild-type rats and mice, suggesting that the three amino acid differences between their Abeta and that of amyloid-bearing mammals impedes the fibrillogenicity of Abeta. Analysis of the primary sequence of the beta-amyloid precursor protein in tree shrews revealed a 98% similarity and 97% identity with the human protein. Furthermore, the predicted amino acid sequence of Abeta in tree shrews is identical to that in humans. However, immunohistochemical analysis failed to reveal beta-amyloid deposits in the neural parenchyma or vasculature of eight aged (7-8 years) tree shrews (Tupaia belangeri). The lack of correlation between the Abeta sequence and amyloid formation suggests that other factors contribute to cerebral amyloid deposition in aged animals.

Aging↗
PubMedDate not supplied

Development of noninvasive and quantitative methodologies for the assessment of chronic ulcers and scars in humans.

Chronic ulcers are a significant and common cause of morbidity and mortality worldwide. They disrupt the epidermis and dermis, resulting in a loss of barrier function. Keloids and hypertrophic scars (benign cutaneous tumors) represent an abnormal healing response. These fibroproliferative disorders are characterized by an overabundance of collagen and accumulation of extracellular matrix due to an imbalance between synthesis and degradation, culminating in excessive scarring. The objectives of this study were to evaluate and compare noninvasive biophysical methods for the measurement of outstanding quantitative parameters of scars and chronic ulcers, and to establish correlations between the parameters measured and the results of conventional subjective clinical evaluations. The development of new technologies, based on ultrasonography and laser Doppler, makes possible new dermatological evaluation methods. Fifteen patients (6 females and 9 males) with 15 chronic ulcers (4 diabetic ulcers, 10 venous ulcers and 1 pressure ulcer) and 30 patients (19 females and 11 males) with 30 scars (25 hypertrophic and 5 keloids) were included in this study. Clinical evaluation was performed by a dermatologist, an aesthetic surgeon and an endocrinologist. Biophysical measurements were used to assess local blood flow by laser Doppler flowmetry (Moor DRT4), thickness and echogenicity by high frequency ultrasonography (20 MHz, Dermascan C) and ulcer linear dimensions by image analysis. Our results show that blood flow within the ulcers and scars was higher than within normal skin. Also, skin thickness of chronic ulcers was decreased when compared to normal skin; the thickness of hypertrophic scars, but not of keloids, was increased in comparison to normal skin, and presented the possibility of measuring wound and scar surfaces with precision. In summary, this pilot study established the feasibility of measuring various biophysical parameters and adapted their potential utility to research on wounds.

Adult↗
PubMedDate not supplied

Gametic associations between inversion and allozyme polymorphisms in Drosophila buzzatii.

Gametic disequilibria between second chromosome polymorphic arrangements and seven linked allozyme loci were estimated in seven populations of Drosophila buzzatii from Argentina. Significant and consistent associations across populations were detected for Est-1, Est-2, Aldox, and XDH: Phenograms based on Nei's genetic distance showed that chromosomes carrying the 2ST arrangement were more similar to each other, irrespective of the population from which they were extracted, than to chromosomes carrying the derived 2J and 2JZ3. Restriction of recombination in heterokaryotypes seems to be the best explanation for the significant linkage disequilibria between inversions and the loci located inside the rearranged segments, for example, Est-1 and Aldox, or close to the break points, for example, Est-2. However, epistatic interactions between Xdh, which is outside the inversions and not near the break points, and loci tightly linked to the inversions, is the most likely explanation for the association between Xdh and chromosomal arrangements. Some of the associations detected in endemic Argentinean populations are coincident with data obtained in colonizing populations of the Old World and Australia. Thus historical processes that took place in the original area of the species' distribution can account for these linkage disequilibria in colonized populations of D. buzzatii.

Animals↗
PubMedDate not supplied

Comparison of two special infant formulas designed for the treatment of protracted diarrhea.

The nutritional management of intractable diarrhea and short bowel syndrome remains a challenging problem. The advantage of continuous nasogastric infusion is undisputed, but what to feed remains in question, and no studies, to these authors' knowledge, have yet compared two widely used specially designed protein hydrolysate formulas. A randomized crossover trial of two periods of 7 days was carried out with Alfare and Pregestimil administered by a constant infusion pump in six malnourished infants aged 1-13 months. Two had intractable diarrhea, and four the short bowel syndrome. Identical quantities of calories were administered during the two periods. There was good tolerance for both formulas and satisfactory weight gain. Despite compositional differences related to osmolality, the source of the hydrolysates and their profile, and the qualitative pattern of the carbohydrates, no difference was observed with regard to stool weight, Na+ and K+ losses, and the enteral absorption of fat, carbohydrate-derived energy, and total energy. The percent absorption of nitrogen was somewhat higher (p less than 0.01) with Pregestimil (83.8 +/- 2.7) than with Alfare (77.3 +/- 3.4), but nitrogen retention was unaffected. Energy absorption was the same on both formulas, but maldigested or malabsorbed carbohydrates accounted for 63% of total energy loss during Alfare feeding and 72% during the week of Pregestimil. These data call for studies with protein hydrolysate formulas reformulated with a lower concentration of carbohydrates and a higher one of fat.

Body Weight↗
PubMedDate not supplied

Essential fatty acid deficiency lowers the activity of the acetylated low density lipoprotein receptor of rat peritoneal macrophages.

We compared phospholipid fatty acid composition, cholesterol ester accumulation, and receptor-mediated binding, internalization, and degradation of acetylated low-density lipoprotein (acetyl-LDL) in cultured peritoneal macrophages from rats fed an essential fatty acid deficient or control diet. The deficient diet increased the 5,8,11-eicosatrienoic acid and decreased the omega 6 fatty acid content of macrophage phospholipid relative to control. The deficient diet did not affect macrophage uptake of [1-14C]oleate; however, it lowered the accumulation of intracellular labelled cholesteroyl oleate to 66% of the control. This effect was attributed to a diminution of the specific binding of acetyl-LDL, and not to acetyl-LDL internalization nor to degradation. The results demonstrate the sensitivity of the acetyl-LDL receptor to changes in its membrane environment, brought about through dietary means.

Acetylation↗
PubMedDate not supplied

HIV-1 IgA specific serum antibodies and disease progression during HIV-1 infection.

OBJECTIVE: To evaluate the role of serum human immunodeficiency virus type 1 immunoglobulin A (HIV-1 IgA) antibodies in the progression of HIV-1 infection in relation to viral load and CD4 cell counts. METHODS: Sequential serum specimens were obtained from 218 homosexual men: 123 HIV-1 seropositives, 24 HIV-1 seroconverters, and 71 HIV-1 seronegatives. HIV-1 IgA antibodies were tested blindly by enzyme-linked immunosorbent assay and Western blot. T-lymphocyte subsets were measured by flow cytometry. Viral plasma load was determined by a sensitive branched DNA assay. RESULTS: HIV-1 IgA antibodies with a titer greater than or equal to 50 were detected among 50% of the seroconverters, 27% of the HIV-1-seropositive asymptomatic subjects, 25% of lymphadenopathy, and 23% of HIV-1-related symptomatic subjects. Among patients with the acquired immune deficiency syndrome, the prevalence of virus-specific IgA antibodies (55%) was significantly higher (p < 0.03) as compared with the HIV-1-seropositive asymptomatic subjects, lymphadenopathy and HIV-1-related symptomatic patients, but not versus the seroconverters (p = 0.8). IgA antibodies to HIV-1 gP160 were the most prevalent among all subjects tested. A significant decrease in CD4 cell counts was observed after HIV-1 seroconversion. Viral load was slightly higher among the seroconverters who demonstrated higher (> or =50) HIV-1 IgA levels. CONCLUSIONS: HIV-1 IgA serum antibodies did not predict the progression of the disease. Correlation between HIV-1 IgA antibodies titer, viral load, and CD4 cell counts was not detected.

Adult↗
PubMedDate not supplied

Late recurrence of malignant melanoma: a report of five cases, a review of the literature and a study of associated factors.

This is a study of factors associated with late recurrence (i.e. 10 or more years after definitive surgery) of cutaneous malignant melanoma (MM). Four factors were evaluated: Breslow thickness, site of the primary MM, age of the patient at initial treatment for MM, and gender. These factors were compared between two groups: (1) Stage I cases in the New York University Melanoma Cooperative Group (NYU-MCG) database that had 'early recurrence' (less than 10 years) of MM, and (2) cases in the literature with late recurrence of MM plus five new cases reported here. Compared to the group of patients with 'early recurrence' of MM, the group of patients who had late recurrence of MM were found more likely to have thinner primary melanomas (p less than 0.001), to be younger (p less than 0.001), to be female (p = 0.001), and, for females, to have the MM located on an extremity (p = 0.017). Because late recurrence does occur and because the risk of developing a new primary MM is increased in MM patients, any patient who has had a MM should be followed for life.

Abdominal Neoplasms↗
PubMedDate not supplied

Lipoprotein lipase in experimental diabetic rats: beneficial effect of vanadate treatment.

Elevated values of circulating triglycerides were observed in streptozotocin-hyperglycemic rat while cholesterol concentrations did not differ from controls. Daily oral administration of sodium metavanadate to these diabetic animals normalized blood glucose values without raising the reduced levels of insulin. Concomitant with the normalization of the glycemia, the elevated triglyceride values found in diabetic rats were also corrected. Lipoprotein lipase activity in adipose and cardiac tissues was significantly decreased in the streptozotocin-diabetic animals. Similarly, the hepatic lipase activity was also depressed. After vanadate treatment, lipoprotein lipase as well as hepatic lipase activities were corrected towards normal values. Thus, vanadate treatment of streptozotocin-diabetic animals induces normalization of blood glucose and triglycerides levels, while maintaining low amounts of circulating insulin. It also restores the depressed activities of adipose and cardiac lipoprotein lipase and hepatic lipase.

Adipose Tissue↗
PubMedDate not supplied

Enhancement of recall of cardiopulmonary resuscitation (CPR): Use of moving-image card to review the dynamics of CPR.

Since victims of cardiac arrest have a more favorable outcome when CPR is immediately applied, it is important to continue to motivate individuals to learn proper technique. It is equally important to ensure that individuals who have learned CPR maintain adequate recall of the procedure. With the intent of enhancing recall of the principles of CPR, a wallet-size plastic card was developed which, when tilted, creates the illusion of movements. Thus, the card enables a viewer to review the dynamic aspects of CPR and reinforces the essential steps of establishing an airway and maintaining breathing and circulation.

Heart Arrest↗
PubMedDate not supplied

Ovarian malignancies in pregnancies complicated by colonic perforation.

Primary or secondary ovarian carcinoma in pregnancy is very rare. The entity is difficult to diagnose and is not infrequently fatal. Two unusual cases of ovarian carcinoma during pregnancy, complicated by perforation of the colon, are described. Treatment depends upon the time of diagnosis, the stage of growth, and possible complications. More attention should be paid to complaints concerning bowel function during pregnancy, and pelvic sonography and bowel studies may enable earlier diagnosis.

Adenocarcinoma↗
PubMedDate not supplied

Intestinal fat malabsorption in the uremic rat.

In the past we have shown that patients with chronic renal failure (CRF) on hemodialysis show evidence of intestinal malabsorption of fat. The present study was designed to verify this finding in an animal model. Male rats weighing +/- 200 g were studied. Uremia (U) was induced by 2-stage subtotal (5/6) nephrectomy. Control (C) animals were sham-operated. Fat absorption was studied after 6 weeks of uremia with the oral fat loading test. Twenty percent intralipid (0.25 g/100 gBW) was given by gastric tube feeding to fasting animals and the appearance of chylomicrons (CHYL) and the rise of triglycerides (TG) in the serum was followed for 5 hrs. In order to isolate the effect of fat absorption, an additional group of U and C animals was pretreated with orotic acid and triton, thus blocking hepatic TG synthesis and neutralizing peripheral lipoprotein lipase activity. The absorption of CHYL was significantly (p less than 0.01) impaired in all U animals and averaged 43 and 70 percent of that of the C animals, 1 and 2 hrs after the load respectively. The rise in serum TG did not differ from C in mildly U animals (Scr 1.0 +/- 0.04). In the more severely uremic animals (Scr 2.6 +/- 0.2), however, pretreated with orotic acid and triton, the rise in serum TG was far less (p less than 0.01) than in C animals (111 +/- 26-903 +/- 111 delta % V.780 +/- 170-5032 +/- 746 delta %) 1 and 5 hrs after the load.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Continuous high-energy low-flow-rate enteral support: a panoramic review of 1000 cases.

One thousand intensive care digestive surgical cases are reviewed concerning continuous low-flow-rate enteral support (CLFRES), using Nutripompe: 607 males and 393 females, average age 51 years. The average duration of CLFRES is 21.5 days +/- 13, range 4 to 180 days. CLFRES was used postoperatively in 76 per cent, preoperatively in 10 per cent, and pre- and postoperatively in 14 per cent of cases, respectively. The enteral support route was 63 per cent nasogastric, 20 per cent gastrostomy and 17 per cent jejunostomy. Five hundred and ten patients required extensive digestive surgery with temporary exclusions. More than 100 patients with either temporary enterostomies or enterocutaneous fistulas have had continuous reinstillation of digestive chyme (CRDC) associated with their intensive care unit treatment management. CRDC in the lower end of an enterostomy has shown a specific retrograde inhibitory effect on the upper digestive secretions, particularly on the intestinal secretions during pathologies associated with one or several interruptions of the continuity of the gastrointestinal tract. This technique and its physiological implications were discussed. The principal pathologies in this important study group are: severe digestive fistulas, 24 per cent; acute diffuse peritonitis, 18 per cent; acute enterocolitis, 14 per cent; digestive tumours, 35 per cent; and acute necrotizing haemorrhagic pancreatitis, 9 per cent. A comparative analysis of nutritional energy nitrogen requirement was presented in view of the cancer, the septic, and the non-cancer non-septic patient groups. Enteral support nutritional solutions were primarily mixed non-degraded food, 70 per cent, and semi-elemental diets, 30 per cent. Certain pathology groups required variations in protein and lipid percentage. An up-to-date evaluation of nutritive formulas based on small peptides in normal and small bowel postoperative patients was discussed. Four CLFRES administration programmes were discussed: normal gastrointestinal tract, 38 per cent; abnormal gastrointestinal tract, 44 per cent; pancreatitis, 11 per cent; short bowel, 7 per cent. Nutrition evolution parameters (clinical), were: weight gain curve (minimum 10 days), local regional healing, biological positive changes in protein metabolism, nitrogen balance, lipid metabolism and glucose regulation. Impact on complications such as thrombosis, embolism and haemorrhage were discussed. Clinical and biological results using CLFRES were most satisfactory in more than 90 per cent of patients.

Adolescent↗