Search PubMed⌕ Search

Biomedical subjects

I Nir

Publications and source records attributed to I Nir.

At least 37 records · Page 2Linked to original sources
PubMed1996

Evaluation of minor penetrating duodenal injuries.

Penetrating duodenal injuries can present a confusing picture for the surgeon. A variety of treatment modalities exist including primary repair alone, primary repair with pyloric exclusion, duodenal resection, duodenal diverticulization, and the Whipple procedure. We reviewed 40 consecutive penetrating duodenal injuries in order to determine factors that led to complications of duodenal injuries, and to determine the most appropriate way to treat these injuries. Fourteen patients had combined pancreaticoduodenal injuries, five of whom developed pancreatitis. None of the patients without a combined pancreaticoduodenal injury developed pancreatitis (P < 0.05). Sixteen patients with minor duodenal injuries were treated by primary repair alone. In this group, five had combined pancreaticoduodenal injuries. Two of these five patients developed a suture line dehiscence and leak (P < 0.05). None of the 11 patients without a combined pancreaticoduodenal injury that were treated by primary repair alone developed a leak. Three patients with combined intermediate pancreaticoduodenal injuries were treated by primary repair with pyloric exclusion. None of these three patients developed a suture line dehiscence or leak. We conclude that combined pancreaticoduodenal injuries are more likely to develop pancreatitis, and that minor or intermediate combined pancreaticoduodenal injuries are more likely to develop a suture line dehiscence and leak. We recommend that the treatment of duodenal injuries be based on severity, location, and the presence of associated injuries. Minor injuries can be treated by primary repair alone, adding pyloric exclusion if there is a concomitant pancreatic injury.

Adolescent↗
PubMed1995

Effects of long-term administration of melatonin and a putative antagonist on the ageing rat.

Adult rats were treated with either melatonin, the putative melatonin antagonist N-(2,4 dinitrophenyl)-5-methoxytryptamine (ML-23), their combination, or a vehicle for 16 months via the drinking water. The survival rates, serum testosterone and densities of 125I-melatonin binding sites in the medulla-pons and hypothalamus of the animals at the age of 27-29 months were significantly higher in the melatonin than vehicle-treated group. Surprisingly, ML-23 without or with melatonin, also prolonged the life-span of the aged animals. ML-23 treatment greatly increased 125I-melatonin binding in the medulla-pons whereas this increase was prevented by melatonin supplementation. Thus melatonin can attenuate age-related decrease in survival rates, testosterone and brain 125I-melatonin binding sites, while chronic blockade by the putative antagonist also elicits melatonin-mimetic responses, perhaps by effecting supersensitivity.

5-Methoxytryptamine↗
PubMed1995

Brief report: circadian melatonin, thyroid-stimulating hormone, prolactin, and cortisol levels in serum of young adults with autism.

An abnormal circadian pattern of melatonin was found in a group of young adults with an extreme autism syndrome. Although not out of phase, the serum melatonin levels differed from normal in amplitude and mesor. Marginal changes in diurnal rhythms of serum TSH and possibly prolactin were also recorded. Subjects with seizures tended to have an abnormal pattern of melatonin correlated with EEG changes. In others, a parallel was evidenced between thyroid function and impairment in verbal communication. There appears to be a tendency for various types of neuroendocrinological abnormalities in autistics, and melatonin, as well as possibly TSH and perhaps prolactin, could serve as biochemical variables of the biological parameters of the disease.

Adolescent↗
PubMed1995

Ultrastructural features of retinal dystrophy in mutant vitiligo mice.

Ultrastructural features of the retinal pigment epithelium and photoreceptor cells were studied in vitiligo (C57BL/6 mivit/mivit) mice. Eyes from 12-day- to 56-week-old animals were analysed. Abnormal photoreceptors were seen in 12-day-old mice. By 3 weeks malformed outer segments were evident in the posterior and equatorial retina, but normal photoreceptors were present in the periphery. By 28 weeks, a marked gradient in cell loss was evident, with a progressive increase in cell viability along the posterior-peripheral axis. Viable intact photoreceptors were still present in the peripheral retina of 56-week-old mice. Melanosome content varied between adjacent pigment epithelium cells in both the posterior and peripheral retina. In the choroid, however, a steep posterior-peripheral gradient in melanosome content was evident with highest pigmentation in the periphery. In the optic nerve head region abnormal development of photoreceptors was correlated with proliferation of abnormal pigment epithelium cells. Accumulation of rod outer segment debris in the posterior and peripheral subretinal space preceded photoreceptor cell death. Short pigment epithelial microvilli without proper attachment to photoreceptors are suggestive of alterations in pigment-epithelium-photoreceptor interaction, which might affect photoreceptor differentiation and phagocytosis of rod outer segments by pigment epithelium cells.

Animals↗
PubMed1995

Effect of age and exogenous amylase and protease on development of the digestive tract, pancreatic enzyme activities and digestibility of nutrients in young meat-type chicks.

Day-old male meat-type chicks were fed a commercial starter diet supplemented with 2 levels of enzyme preparations containing amylase and proteases up to 14 d of age. Enzyme supplementation had no significant effect on feed intake or growth rate, and was accompanied by a significant decrease in gizzard content and small intestine weight. The intestine contents increased and this increase was accompanied by a significant decrease in its pH. Enzyme supplementation depressed the activity of chymotrypsin in the pancreas and the activity of amylase, trypsin and chymotrypsin in the intestinal contents. Some carry-over effects were observed on d 42, 4 weeks after the cessation of the enzyme supplements. These were mainly a significant depression in the activity of trypsin in the intestinal contents. In a balance study, diets supplemented with 0,250 and 1,000 micrograms/kg enzyme preparations were supplied. Exogenous enzyme supplements had no significant effect on the digestibility of all the nutrients studied except for the highest level of enzyme supplementation, which improved slightly but consistently the digestibility of amino acids. Some age effects were observed, mainly a decrease in the digestibility of fat and starch, and in the ME of the diet from weeks 1 to 2 followed by an increase during week 3. Protein digestibility and retention of nitrogen decreased with age.

Aging↗
PubMed1995

Stunting syndrome in broilers: physical, physiological, and behavioral aspects.

The effect of stunting syndrome (SS) on young broilers induced by orally administering an inoculum prepared from intestines of SS-affected broiler chicks was studied in two experiments. Depression of growth, feed intake, and feed utilization, respectively, was negatively related to the age of inoculation, i.e., highest at posthatch inoculation (63, 57, and 61%), and intermediate at the ages of 3 (42, 45, and 50%) and 7 d (29, 34, and 53%), whereas at the age of 14 d inoculation was ineffectual and the inoculated chicks performed similarly to the naive controls. Eating behavior was determined by periodically recording the number of chicks in each treatment group exhibiting this behavior, i.e., pecking mash in the feeder or pecking the litter. Eating activity was much higher in inoculated chicks (about 20 to 24%) than in the naive controls (6 to 12%) and as with performance negatively related to the age of inoculation. In chicks inoculated at the age of 14 d, eating activity was quite similar to that of the naive control chicks. Noninoculated chickens raised in the same room as their inoculated counterparts were infected by the disease agents. In some respects the consequences of horizontal infection were similar to those observed in inoculated chicks, i.e., depressed feed intake, growth, and feed utilization and a heavier heart, crop, proventriculus, gizzard, intestine, and gastrointestinal contents. In contrast, the activities of the pancreatic digestive enzymes were more similar to those of the naive controls than to those of the inoculated groups. At the age of 14 d, activities of amylase, trypsin, chymotrypsin, and lipase in the pancreas were lower in the inoculated than in the naive control birds. At the age of 21 d, the results were reversed and activity in the inoculated birds was higher than in the naive control birds. During both periods, the activity of pancreatic lipase was higher in the naive controls than in the inoculated birds. The hyperactivity estimated via a determination of eating activity suggests that SS is an affliction not only of digestion but also of metabolism.

Aging↗
PubMed1995

Effect of particle size on performance. 3. Grinding pelleting interactions.

Three experiments were conducted to study the effect of particle size obtained by grinding wheat and sorghum in a hammer mill (HM) or roller mill (RM) on broiler performance. Broilers were fed a mash diet or crumbles to 4 wk of age, then pellets to 7 wk of age. When fed as a mash, diets produced with RM-ground grain improved performance. The effect of grinding was additive to that of pelleting. The interactive effects observed between grinding method and the form of the feed on body weight and feed intake were explained by the higher response to pelleting when grains were ground in HM vs RM. The positive effect of grinding in RM on feed utilization was found to be additive to that of pelleting in all three experiments. The response of females to feed texture was less pronounced than that of males. In males, feeding pellets vs mash increased mortality due to ascites threefold, whereas grinding method had no effect. Females were less susceptible to ascites than males, and feed texture had no effect in this respect. The effects of grinding and pelleting on the gastrointestinal tract segments were additive. The main effects of feed texture were a significant increase in stomach weight and that of its contents following HM grinding and a decrease in these following pelleting, with no interactions between the two.

Adipose Tissue↗
PubMed1995

Effects of dietary protein under high ambient temperature on body weight, breast meat yield, and abdominal fat deposition of broiler stocks differing in growth rate and fatness.

The effect of dietary protein on growth, feed intake and efficiency, abdominal fat deposition, and breast meat yield was investigated in broiler males from a commercial stock (WI) and from experimental stocks selected for low (LF) or high (HF) abdominal fat. All birds were kept at constant high ambient temperature (32 C) and were provided with low- (LP) or high-protein (HP) diets from hatch until 8 wk of age (Experiment 1) or from 4 to 8 wk of age (Experiment 2). In both experiments, HP diet significantly increased 4- to 8-wk BW gain in the LF and HF stocks but reduced it in the WI stock as compared with the LP diet. Abdominal fat, as percentage of BW, was almost twofold higher in the HF birds than in the LF ones, with WI mean being intermediate. In contrast to the HF and WI birds, in which abdominal fat decreased with increased protein intake, abdominal fat was not affected by dietary protein in the LF stock. The HP diet substantially increased breast meat yield in LF birds but not in the WI birds, with HF birds exhibiting intermediate increase in breast meat weight. It was concluded that birds of varied inherent growth rate and tendencies toward protein and fat deposition respond differently to dietary protein level under heat stress.

Adipose Tissue↗
PubMed1995

Stunting syndrome in broilers: effect of age and exogenous amylase and protease on performance, development of the digestive tract, digestive enzyme activity, and apparent digestibility.

Day-old male, meat-type chicks raised in brooder batteries were infected by orally administering an inoculum prepared from intestines of broiler chicks infected with stunting syndrome (SS). Naive controls were kept in a parallel room. The chicks were fed a commercial starter diet supplemented with two levels of enzyme preparations to 14 d of age. The experiment was continued to the age of 6 wk in order to estimate compensatory feed intake and growth. In a parallel study, digestibility of the feed was determined from 1 to 3 wk of age with control or inoculated chicks. The enzymes amylase and proteases were produced by Bacillus subtilis and Penicillium emersonii. Enzyme supplementation had no effect on feed intake, growth, or feed utilization, or on digestibility of fat, starch, protein, or energy. Because enzyme supplementation did not consistently affect performance of chicks and no interactions were observed between enzyme supplementation and infection status, data are presented for effects of infection only. Inoculation of SS-infective material reduced performance to 4 wk. Compensatory growth and feed intake were observed from the age of 4 wk onward. At the age of 6 wk the slight retardation of the inoculated chicks was not significant. On Week 1, retention of fat, starch, protein, and energy was significantly depressed in the inoculated chicks. At the age of 2 wk, retention of starch was not depressed, and at the age of 3 wk, the only consistent depression was that observed for fat. The proventriculus weight and content were consistently higher in inoculated chicks, as were the small intestine and intestinal content. The pH of the gizzard content was higher, and that of the small intestine content was lower, in the inoculated birds than in their control counterparts. Stunting syndrome infection was accompanied by a significant depression of trypsin activity in the pancreas at the age of 1 and 2 wk. At these periods, amylase and chymotrypsin were not affected. At 6 wk of age, the activities of amylase, trypsin, and chymotrypsin in the pancreas were higher in the inoculated than in the control birds. In the intestinal chime, amylase, trypsin, and chymotrypsin activities were lower in the inoculated birds on Week 1 and 2 (NS for amylase on Week 1). On Week 6, the activity of all enzymes assayed was higher in the inoculated birds (NS for amylase). It is suggested that the main factors depressing feed intake and growth in SS-infected birds are most probably beyond those of digestion.

Aging↗
PubMed1994

Alterations in light-evoked dopamine metabolism in dystrophic retinas of mutant rds mice.

In dystrophic retinas of rds mice, which are devoid of photoreceptor outer segments, high steady state levels of dopamine were found in dark and light periods. These levels were similar to those observed in normal, BALB/c mouse retinas. Major differences were determined, however, between dopamine turnover in normal and dystrophic retinas. While substantial light-evoked elevation of dopamine synthesis and utilization was observed in normal retinas, dopamine synthesis and metabolism in rds retinas was very low and response to light was depressed. Retinal dopamine metabolism was already depressed in 2 week old rds mice, prior to the onset of photoreceptor cell death, relative to that in age-matched BALB/c mice. At 1 month of age, robust light/dark differences in retinal dopamine metabolism were observed in BALB/c mice, while no significant effect of light was seen in rds mice. The limited ability of the dopaminergic system in rds retinas to respond to light may be due to the absence of normal outer segments. Interestingly, in old rds retinas, although most photoreceptor cells had degenerated, a small but significant light-evoked increase in dopamine metabolism was measured. The presence of relatively high steady state levels of dopamine in rds retinas, despite the reduced dopamine synthetic activity, is maintained by a compensatory reduction in dopamine utilization. Thus, although a considerable amount of dopamine is present in the rds retina, it might not be available to exert its biological functions.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Loss of diurnal arrestin gene expression in rds mutant mouse retinas.

Despite the important advances in the molecular analysis of retinal degenerations, the causes of photoreceptor cell death in these conditions are unclear. To explore the metabolic impact of the rds mutation, we have continued our investigations on the expression of arrestin. Normal BALB/c mouse retinas have a diurnal variation in arrestin gene expression and protein biosynthesis, with low levels in dark-adapted and high levels in the light-adapted retinas. In contrast, arrestin is expressed in rds retinas at high levels throughout the diurnal cycle. A lack of a distinct diurnal cycle and continuously high expression of arrestin in rds retinas might be a reflection of metabolic derangements in these cells which are not an obvious consequence of the underlying molecular defect in the rds/peripherin gene.

Adaptation, Ocular↗
PubMed1994

The antigonadotrophic effect of melatonin in Syrian hamsters is modulated by prostaglandin.

PGE2 was shown to play an essential role in the gonado-inhibiting effect of melatonin in Syrian hamsters by transforming the neuroendocrine signal to gonadal reactivity. Prostaglandin is a vital link in the transduction of photoperiodic information into gonadal function and the difference in its levels brought about by melatonin given at different times of the day could explain the phenomenon why gonadal involution occurs only upon administration of melatonin towards the end of the day. It appears also that the melatonin signal is decoded in the pituitary, probably involving the short loop negative feedback of LH on LH-RH hormones.

Animals↗
PubMed1994

Quantitative effects of pelleting on performance, gastrointestinal tract and behaviour of meat-type chickens.

1. In an attempt to quantify the effects of "degree" of pelleting, two experiments were conducted. Diets were prepared by mixing together a mash composed mainly of maize (experiment 1) or sorghum (experiment 2) with soft pellets, or soft pellets mixed with hard pellets. 2. The pelleting degrees (PDs) were as follows: 0 mash; 0.5 mixture of soft pellets and mash 1 to 1; 1 soft pellets pelleted once; 1.5 mixture of soft and hard pellets 1 to 1; 2 hard pellets pelleted twice. 3. In experiment 2, the weight and length of the digestive organs were determined as well as digestive enzyme activities. In both experiments, the behaviour recorded was eating, standing, sitting and drinking. 4. Food intake and body weight gain were related to the degree of pelleting in a curvilinear manner. PD had a positive effect up to a peak (1 to 1.5 PD), after which its effect decreased. Food efficiency was not related to PD. In experiment 1, food efficiency of PDs 1 to 2 were superior to PDs 0 to 0.5 and in experiment 2, PDs 1.5 to 2 were superior to PD 0. 5. The relative weight of the gizzard was reduced by pelleting, whereas pelleting increased the relative weight of abdominal fat. The content of the crop was not affected by PD, whereas that of the proventriculus was lowest in the PD 2 group. Gizzard content was inversely related to PD. Pelleting reduced the length of the jejunum and ileum: which were shortened by about 15% with PDs 1 to 2, as compared to PD 0. The weight/length ratio of the jejunum and ileum tended to increase with increasing PD to a peak at PD 1.5, and to decrease thereafter. 6. Trypsin activity in the pancreas and amylase activity in the intestinal content were reduced by pelleting. 7. Chicks fed pelleted diets were less active: they 'sat' more and spent less time eating than their mash-fed counterparts.

Adipose Tissue↗
PubMed1994

Effect of particle size on performance. 1. Corn.

The effect of diets prepared with corn ground in a hammer mill and sieved to obtain "coarse", "medium", and "fine" particle size fractions, on broiler performance from hatch to 7 d and from 7 to 21 d of age was studied. Five diets differing in geometric mean diameter (GMD) or geometric standard deviation (GSD) were assayed. The best performance in both age groups studied was obtained with the diet prepared from medium corn. In this diet the GMD was .769 mm, quite similar to those of two other diets (GMD .793 and .706 obtained by mixing the original corn with 18 or 36% "fine" fraction) with which lower performance was obtained. The uniformity of the particle size (described by the GSD) also had a positive effect on performance. The improved performance obtained with the diet containing the medium corn particle size could be partly attributed to lower GSD, which was 1.63 vs about 2.00 in the other diets.

Animal Feed↗
PubMed1994

Effect of grain particle size on performance. 2. Grain texture interactions.

Diets were prepared with corn, wheat, or sorghum ground in a hammer mill and sieved to obtain coarse, medium, and fine particle size fractions. Their effect on broiler performance from hatch to 7 d and from 7 to 21 d of age was studied. The effect of particle size on the size and pH of the gastrointestinal organs was also determined. The three textures obtained for each grain were uniform in geometric mean diameter (GMD) and geometric standard deviation (GSD). Grain by texture interactions were not significant. Independent of grain source, the best performance was obtained with diets prepared from the medium texture. In these diets, the GMD of the grains varied from 1.13 to 1.23 mm and the GSD from 1.19 to 1.35. The fine fraction (GMD .57 to .67 mm) resulted in the lowest performance and that resulting from the coarse fraction (GMD 2.01 to 2.10 mm) was intermediate. At 7 and 21 d of age, gizzard weight and content were positively related to particle size. At the age of 21 d, duodenum weight and content was highest in chicks fed the fine diets. The pH of the gizzard content decreased with increasing grain particle size, whereas that of the small intestinal content increased. Some grain effects were also observed on the gastrointestinal tract. Gizzard weight was greatest in the cornfed birds. Wheat-fed chicks had the heavier intestines and contents. After overnight feed deprivation, feed consumption by 7-d-old chicks was related to the particle size during the first 2 h of refeeding, with greater intake of medium and coarse grains.

Animal Feed↗
PubMed1993

Ultrastructural analysis of arrestin distribution in mouse photoreceptors during dark/light cycle.

Arrestin localization was studied in BALB/c mice retinas during a 12-hr dark/light diurnal cycle and under various light/dark interruptions. Intracellular distribution of arrestin in photoreceptor cells was determined by immunocytochemistry and electron microscopy. During the light phase of the diurnal cycle, arrestin was localized mostly in the rod outer segments. During the dark phase of the cycle, arrestin was localized mostly in the inner segment, nuclei and synaptic terminals. The disc domains of the rod outer segments were labeled at a low density, but conspicuous cytoplasmic regions in the outer segment were labeled at a very high density. These cytoplasmic regions were not labeled in our illuminated retinas. Hence, intrasegmental segregation within the outer segment may be influenced by environmental lighting. During dark adaptation, increase in inner segment labeling density was observed. In previous studies, decrease in outer segment and increase in inner segment labeling density in the dark, as determined by light microscopy, was interpreted as movement of arrestin from the outer to inner segments. Our present ultrastructural analysis of arrestin distribution indicates that yet undetermined amounts of arrestin accumulate in localized regions of the outer segment in the dark. The extent of movement of arrestin to the inner segment, if it occurs, remains to be established. Localization of arrestin in phagosomes indicates that at least part of the arrestin is being degraded in the pigment epithelium.

Animals↗