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N Levin

Publications and source records attributed to N Levin.

At least 37 records · Page 2Linked to original sources
PubMed2000

Determining the time and day of photography.

Photographs taken by crime victims and perpetrators are at times important evidence. Their time of photography may also affect their value as such. Three methods of determining when a picture was taken by using the content of the picture are presented. The methods utilize solar direction-measured from shadows in the photograph, identifying flowering wild plants and correlating cloudiness with meteorological observations. Solar direction is the most accurate and involved method and therefore is the main part of this paper. A case using all three methods is described.

Crime↗
PubMed2000

Improved method for shooting distance estimation. Part 1. Bullet holes in clothing items

An improved method for firing distance estimation on clothing is described. The novel part of the method includes transfer of total nitrite (nitrite ions and smokeless powder residues) from the target to an adhesive lifter. After the transfer, lead and copper deposits around the bullet entrance hole are visualized by rhodizonate and rubeanic acid, respectively. The Modified Greiss Test is carried out after alkaline hydrolysis of the smokeless powder residues on the adhesive lifter.

Journal Article↗
PubMed2000

Improved method for shooting distance estimation. Part III. Bullet holes in cadavers.

An improved method to estimate firing distance on human body surfaces is described. The novel part of the method includes a chemical test in addition to the traditional visual and microscopic examinations of the gunshot wounds. This chemical test consists of a transfer of the gunpowder residues from the area of a gunshot wound to an adhesive lifter; the residues are then visualized as total nitrite after alkaline hydrolysis by the Modified Griess Test (MGT). When cadavers are in an advanced stage of decomposition or when gunshot wounds are in hairy areas, the information obtained by this chemical test can be crucial for shooting distance evaluation. In other cases it may improve the accuracy of the examination. In some cases, the results obtained by this test may assist in the discrimination between entrance and exit gunshot wounds.

Adhesives↗
PubMed1999

The human Prp8 protein is a component of both U2- and U12-dependent spliceosomes.

This study reports the cloning, sequencing, and development of antisera against the human U5 snRNP 220-kDa protein or hPrp8p. Prp8p is the most highly conserved large nuclear protein known to date, but it is not related to any other protein. Southern, Northern, and expressed sequence tag analyses indicate that hPrp8p is encoded by a single gene. Prp8p is a core component of U5 snRNP and the U4/U6.U5 tri-snRNP, and antibodies raised against it immunoprecipitate both the major, U2-dependent and minor, U12-dependent spliceosomes. These spliceosomes, which excise different classes of introns, contain distinct sets of snRNAs overlapping only with U5 snRNA. Other than the core Sm proteins, hPrp8p is the first splicing factor shown to be common to both spliceosomes.

Amino Acid Sequence↗
PubMed1999

Starvation: early signals, sensors, and sequelae.

To identify the sequences of changes in putative signals, reception of these and responses to starvation, we sampled fed and starved rats at 2- to 6-h intervals after removal of food 2 h before dark. Metabolites, hormones, hypothalamic neuropeptide expression, fat depots, and leptin expression were measured. At 2 h, insulin decreased, and FFA and corticosterone (B) increased; by 4 h, leptin and glucose levels decreased. Neuropeptide Y messenger RNA (mRNA) increased 6 h after food removal and thereafter. Adrenal and plasma B did not follow ACTH and were elevated throughout, with a nadir at the dark-light transition. Leptin correlated inversely with adrenal B. Fat stores decreased during the last 12 h. Leptin mRNA in perirenal and sc fat peaked during the dark period, resembling plasma leptin in fed rats. We conclude that 1) within the first 4 h, hormonal and metabolic signals relay starvation-induced information to the hypothalamus; 2) hypothalamic neuropeptide synthesis responds rapidly to the altered metabolic signals; 3) catabolic activity quickly predominates, reinforced by elevated B, not driven by ACTH, but possibly to a minor extent by leptin, and more by adrenal neural activity; and 4) leptin secretion decreases before leptin mRNA or fat depot weight, showing synthesis-independent regulation.

Adipose Tissue↗
PubMed1998

Up-regulation of blood-brain barrier short-form leptin receptor gene products in rats fed a high fat diet.

Leptin is a 16-kDa protein synthesized in adipose tissue that produces a satiety effect in the CNS. Leptin may gain access to the brain via receptor-mediated transport through the blood-brain barrier (BBB), and the BBB leptin receptor (OBR) may regulate the availability of circulating leptin to brain cells. The aim of the present study was twofold: first, to identify the OBR isoform expressed at the BBB, i.e., short, or "a," and long, or "b," form; and second, to compare the abundance of the BBB OBR mRNA and protein between control and high fat-fed rats. RT-PCR with isoform-specific primers showed that OBRa is the most abundant isoform at the BBB. BBB OBRa transcript content was markedly increased in high fat-fed rats compared with controls (11-fold), and no changes were observed in the expression of the internal standard control actin. The high fat feeding induction of OBR mRNA was correlated with an increase in the immunoreactive BBB OBR determined by immunocytochemistry using an all-isoform reactive antibody in high fat-fed obese rats. This investigation demonstrates (a) the OBRa is the principal leptin receptor expressed at the BBB and (b) this BBB OBR isoform is up-regulated by a high fat diet.

Animals↗
PubMed1998

Identification of zinc phosphide in a falsely labeled rodenticide bait.

"Kela" is a commercial rodenticide bait commonly used in Israel, made of wheat grains, which, according to its label, contains chlorophacinone. This product was involved in the death case of a man in which the victim's female companion was accused of assisting in this suicide and was subsequently convicted. Analysis of the wheat grains revealed zinc phosphide, whose use is restricted to authorized exterminators only, instead of chlorophacinone. Zinc phosphide was identified using microscopic examination, scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and X-ray powder diffraction (XRD).

Aged↗
PubMed1998

Acute alcohol effects on opiomelanocortinergic regulation.

To assess acute effects of alcohol on forebrain and pituitary opiomelanocortinergic regulation, a model was developed in which "experienced" (previously introduced to ethanol administration, so the subjective response was not a novel stimulus) male Sprague-Dawley rats received pulsatile intragastric ethanol infusions during the dark (active) photophase to produce and sustain (for 3 hr) behaviorally relevant (0, 40 to 70, 80 to 110, or 120 to 150 mg/dl) plasma ethanol levels. The effects of alcohol on hypothalamo-pituitary-adrenal (H-P-A) axis function were biphasic with respect to dosage (inhibition with low dosage and stimulation with higher dosages) and time (initial stimulation with higher dosages was followed by rapid return to control levels even though elevated plasma ethanol levels were maintained). The effects of alcohol on H-P-A activation were also inconsistent; some of the animals did not appear to respond even though elevated (i.e., >100 mg/dl) plasma ethanol levels were produced. Induction of moderate (80 to 110 mg/dl) plasma ethanol levels acutely (within 30 min) increased immunoreactive (i) beta-endorphin concentrations in the ventral tegmental area of the brain; higher (120 to 150 mg/dl) plasma ethanol levels increased i beta-endorphin concentrations in both the ventral tegmental area and the nucleus accumbens, whereas i beta3-endorphin concentrations were not significantly altered in other brain areas. High (120 to 150 mg/dl) plasma ethanol levels also increased mediobasohypothalamic pro-opiomelanocortin (biosynthetic precursor of forebrain beta-endorphin) mRNA concentrations at 3 and 6 hr after initiation of ethanol infusions. Results demonstrate that atraumatic induction of physiologically meaningful plasma alcohol levels by gastric ethanol infusion activates the forebrain opiomelanocortinergic opioid system and exerts complex effects on the interrelated H-P-A system, consistent with evidence that these systems may interact to mediate or modulate some responses to alcohol ingestion.

Adrenocorticotropic Hormone↗
PubMed1997

Patient's view of dialysis care: development of a taxonomy and rating of importance of different aspects of care. CHOICE study. Choices for Healthy Outcomes in Caring for ESRD.

Quality assessment efforts to enhance public accountability in dialysis care and to support provider efforts to improve care have lacked patient input. To develop brief patient evaluation or satisfaction surveys suitable for busy clinical settings, knowing patients' priorities can be helpful in deciding which aspects of care should be tracked. We conducted a study to identify salient attributes of dialysis care and to rank the importance of these attributes from the perspective of dialysis patients. We analyzed the content of patient focus group transcripts to characterize dialysis care from the patients' perspective. We then surveyed 86 patients to determine how patients would rank the importance of each aspect to quality of dialysis care. The 18 broad aspects of care identified in the focus group included: (1) care provided by nephrologists, (2) care provided by other physicians (nonnephrologists), (3) care provided by dialysis center nurses, (4) care provided by social workers and psychologists, (5) care provided by dieticians, (6) clergy, (7) care provided by technicians and physician assistants/nurse practitioners, (8) care provided by dialysis center staff in general, (9) supplies, (10) treatment choice and effectiveness, (11) patient education and training, (12) self-care, (13) dialysis machines, (14) unit environment and policies, (15) cost containment, (16) billing, (17) cost of care, and (18) health outcomes. Items ranked in the top 10 by both groups of patients included issues related to nephrologists, other doctors, nurses, and patient education and training. Compared with hemodialysis patients, peritoneal dialysis patients gave higher ratings to hospital doctors' and nurses' attention to cleanliness when working with access sites, how correct the nephrologist's instructions to patients are, whether emergency room doctors check with nephrologists, the amount of information patients get about their diet, and how well nurses answer patients' questions. Patients value certain aspects of dialysis care highly, and these aspects differed in some respects for the relatively small number of hemodialysis and peritoneal dialysis patients studied. Construction of brief questionnaires for quality assessment and assurance requires thoughtful consideration of what questions to include. Knowing patients' priorities regarding the most important aspects of care that have high potential for dissatisfaction may be helpful to continuous quality improvement of end-stage renal disease care.

Adult↗
PubMed1997

National Kidney Foundation: Dialysis Outcome Quality Initiative--development of methodology for clinical practice guidelines.

BACKGROUND: The NKF-DOQI (National Kidney Foundation--Dialysis Outcomes Quality Initiative) began in March 1995 with the following objectives: To improve end-stage renal disease (ESRF) patient survival, to reduce patient morbidity, to increase efficiency of care, and to improve quality of life for ESRF patients. METHODS: The development of the NKF-DOQI Clinical Practice Guidelines focused on haemodialysis adequacy, peritoneal dialysis adequacy, vascular access, and anaemia. Principles guiding the methodology included scientific and methodological rigour, interdisciplinary approach, independence of the Work Groups, and an open review process. Unique features of this evidence-based guideline development process included the use of mock guidelines and rationales to guide the literature research, and an unprecedented three-stage review process. RESULTS: Work Groups reviewed more than 11,000 articles. A total of 114 clinical practice guidelines were developed by the Work Groups; these have been reviewed by more than 1200 professionals and patients. CONCLUSION: The NKF-DOQI Clinical Practice Guidelines has been a unifying effort for the entire renal community. The guidelines are an important step in the process of improving the quality of dialysis practice and improving ESRF patient outcomes. Priorities for implementation of the guidelines include education of ESRF professionals and patients, working with providers and insurers to encourage compliance, and follow-up evaluation of patient outcomes to quantify compliance results.

Foundations↗
PubMed1997

Elevated corticosterone is not required for the rapid induction of neuropeptide Y gene expression by an overnight fast.

Fasting stimulates corticosterone (B) secretion and the expression and secretion of hypothalamic neuropeptide Y in rats. These studies tested the hypothesis that the rapid and marked fasting-induced increases in plasma B are responsible for stimulation of neuropeptide Y (NPY) gene expression. Plasma leptin and insulin were measured because they are also signals known to affect NPY messenger RNA (mRNA). Intact or adrenalectomized rats given a low fixed level of corticosterone (B replaced) were fasted for 48 h. NPY mRNA in the mediobasal hypothalamus, measured by nuclease protection assay, was elevated similarly above ad lib-fed controls in both intact and B replaced groups at 15 and 48 h after the onset of fasting. NPY immunoreactivity in the mediobasal hypothalamus increased between 3 and 48 h after onset of the fast in intact but not in B replaced groups. The fasting-induced decreases in leptin observed in intact rats at 48 h did not occur in B replaced rats. Fasting-induced decreases in insulin occurred in B replaced rats but not in intact rats. We conclude that: 1) elevated B is not required for fasting-induced increases in hypothalamic NPY gene expression; and 2) decreases in neither leptin nor insulin alone signal the changes that occur in NPY mRNA in fasted rats.

Adrenalectomy↗
PubMed1997

Cloning and characterization of a human leptin receptor using a biologically active leptin immunoadhesin.

Leptin, the product of the ob gene, is a hormone secreted by fat cells which is primarily involved in the regulation of body weight. We have generated a leptin immunoadhesin (leptin-IgG) which was more potent than leptin alone at reducing body weight and food intake when injected into ob/ob mice. This molecule was used to identify high affinity binding sites on human embryonic 293 kidney cells and subsequently to isolate a cDNA encoding the leptin receptor from this cell line by expression cloning. This receptor corresponds to the short form of the recently isolated leptin receptor. Analysis of the expression pattern of the two forms of receptor by Northern blot, in situ hybridization and quantitative PCR showed that the receptor is expressed in most tissues but that the long form is prevalent in the hypothalamus.

Animals↗
PubMed1996

Decreased food intake does not completely account for adiposity reduction after ob protein infusion.

The effects of recombinantly produced ob protein were compared to those of food restriction in normal lean and genetically obese mice. Ob protein infusion into ob/ob mice resulted in large decreases in body and fat-depot weight and food intake that persisted throughout the study. Smaller decreases in body and fat-depot weights were observed in vehicle-treated ob/ob mice that were fed the same amount of food as that consumed by ob protein-treated ob/ob mice (pair feeding). In lean mice, ob protein infusion significantly decreased body and fat-depot weights, while decreasing food intake to a much lesser extent than in ob/ob mice. Pair feeding of lean vehicle-treated mice to the intake of ob protein-treated mice did not reduce body fat-depot weights. The potent weight-, adipose-, and appetite-reducing effects exerted by the ob protein in ob protein-deficient mice (ob/ob) confirm hypotheses generated from early parabiotic studies that suggested the existence of a circulating satiety factor of adipose origin. Pair-feeding studies provide compelling evidence that the ob protein exerts adipose-reducing effects in excess of those induced by reductions in food intake.

Adipose Tissue↗
PubMed1996

Developmental differences in the IGF-I system response to severe and chronic calorie malnutrition.

Recent studies in children suggest that there are age-related differences in the insulin-like growth factor I (IGF-I) response to malnutrition. To extend this observation, immature 4-wk-old male rats were fasted for 3 days, fed ad libitum (control), or fed 60 or 40% of control calories (restricted) and compared with 8-wk-old young adults. Over the 3-wk study period, serum total IGF-I levels of the older rats were stable despite reduced insulin levels, whereas IGF-I increased 2.2-fold in the younger controls. With the 40% diet, younger and older rats changed body weight +1 and -1 body wt/day, respectively (P < 0.0001). The restricted younger animals reduced serum IGF-I IGF binding protein-3, acid-labile subunit, and growth hormone binding protein levels significantly more than the restricted older animals. Fasting decreased most of these parameters by 40%, serum insulin by approximately 80%, and body weight by 9%, regardless of age. We conclude that the suppression of the IGF-I system in response to chronic undernutrition, but not acute fasting, is greater in maturing than young adult rats.

Aging↗
PubMed1995

Hyperadrenocorticism and food restriction-induced life extension in the rat: evidence for divergent regulation of pituitary proopiomelanocortin RNA and adrenocorticotropic hormone biosynthesis.

The increased diurnal elevation of plasma corticosterone (B) induced by food restriction (FR) may play a role in the life span extension of FR. We investigated whether FR alters adrenocorticotropic hormone (ACTH) and proopiomelanocortin (POMC) mRNA levels in plasma and anterior pituitary (AP), since these molecules both regulate and can be suppressed by B. Measurements were made in 3-month-old male Fischer 344 rats that had been ad libitum (AL) or FR (60% of AL calories) since 6 weeks of age. Plasma B was 2-fold higher in FR rats in the PM samples, but did not differ in AM samples. By contrast, plasma ACTH did not differ in the PM samples of FR and AL rats and was 20% lower in AM samples (p < .05) of FR rats. AP content of ACTH was 50% lower in FR rats in both AM and PM samples (p < .01). In contrast, AP contents of POMC and mRNA, primary transcript, and processing intermediate were not reduced in FR rats, and PM content of POMC primary transcript was elevated in FR rats (p < .05). The reduced pituitary and plasma ACTH of FR rats may be the consequence of their elevated plasma B levels. This study also suggests that factors other than elevated ACTH account for FR-induced hyperadrenocorticism. These results also indicate that POMC mRNA and ACTH biosyntheses are differentially regulated in FR rats.

Adrenocorticotropic Hormone↗
PubMed1995

Adaptation of the growth hormone and insulin-like growth factor-I axis to chronic and severe calorie or protein malnutrition.

The hierarchy of diet components (e.g., protein, carbohydrate, vitamins, and minerals) influencing growth hormone (GH), insulin-like growth factor-I (IGF-I), and their binding proteins (BP) is not well defined. Young adult rats were fed diets for 1 mo that included low protein or 60% and 40% of carbohydrate calories. We hypothesized that levels of both hormones, their dominant BPs and liver IGF-I mRNA would fall, and that part of the mechanism for decreasing serum IGF-I would be enhanced IGFBP-3 protease activity. By day 30, caloric deprivation to 40% lowered serum GH, GHBP, IGF-I and IGFBP-3, and liver IGF-I mRNA. This was the only condition resulting in body weight loss (-15%) vs 39% gain in controls. Restriction to 60% calories had no impact on BP levels, slightly lowered IGF-I (-12%) in the face of a 95% inhibition of GH levels, while allowing a modest 9% body weight gain. Protein deprivation lowered serum GH, IGF-I and IGFBP-3, and liver IGF-I mRNA, while GHBP levels were normal. The reduced total IGF-I under these dietary conditions could not be explained by an increase in IGFBP-3 protease activity, or a decrease in the association of IGF-I with IGFBP-3 and the acid labile subunit.

Amino Acid Isomerases↗