[Antihistamines and sedation].
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Histamine H1 Antagonists↗
Biomedical subjects
I Nir
Publications and source records attributed to I Nir.
Diabetic neovascularization: permeability and ultrastructure.
The permeability of newly formed blood vessels in proliferative diabetic retinopathy at different stages of development was correlated with their ultrastructural features. The young proliferating vessels were much more permeable to fluorescein than were the older vessels. Transmission electron microscopy revealed that the blood vessels within the young intravitreal proliferating fronds had intermediate interendothelial junctions, whereas the blood vessels within the old neovascular preretinal membranes had tight interendothelial junctions of the macula occludens type. Fenestrations were observed only rarely in the endothelial wall of either the young or the older proliferating vessels. We conclude that the principal route of fluorescein leakage from the newly formed blood vessels in proliferative diabetic retinopathy is via the interendothelial clefts.
Adult↗
Sialic acid on the surface of photoreceptors and pigment epithelium in RCS rats.
Incubation of isolated retinas and pigment epithelium (PE) from normal and dystrophic RCS rats with colloidal iron (CI) at pH 1.8 resulted in dense labeling of rod outer segments (ROS) and PE surfaces. Pretreatment with neuraminidase reduced subsequent binding of CI. The authors conclude, therefore, that sialic acid residues are localized on the ROS and PE surfaces. In dystrophic rats, uningested ROS tips, which accumulate in the subretinal space, did not bind CI.
Animals↗
Body weight and composition of Japanese quail (Coturnix coturnix japonica) at sexual maturity.
The influence of dietary protein (26%, 24%, 20%, 16%, and 14%) and restricted feeding (100%, 80%, and 60% of ad libitum) on body weight and body composition of Japanese quail (Coturnix coturnix japonica) at sexual maturity was examined in two similar experiments. Although less variable than chronological age, body weight at sexual maturity also differed significantly. In Experiment 1, there were no significant differences in breast weight, tibia length or carcass fat due to diet. In Experiment 2, differences in body composition were apparent as age at the onset of lay was increased by dietary manipulation. Early maturing quail tended to enter lay when a minimum chronological age or critical body lipid level was reached; late maturing quail entered lay when a critical lean body weight or skeletal size was reached. It is proposed that multiple threshold traits associated with growth and body composition are critical for the onset of sexual maturity.
Aging↗
Effect of psychotrophic drugs on [14C]tryptophan metabolism in cultured rat pineal gland.
A potentiated production of [14C]melatonin ([14C]Mt) with a simultaneous decline in [14C]serotonin ([14C]5-HT) conversion to its final metabolite [14C]5-hydroxyindole acetic acid ([14C]5-HIAA) was recorded in a rat pineal medium cultured with [14C]tryptophan and either a neuroleptic [haloperidol (HAL) or chloropromazine (CPZ)] or an antidepressant [desipramine (DIP)] drug. A difference between the pharmacological groups of drugs was evident only in [14C]5-HT levels, which were found significantly elevated in the presence of the neuroleptic HAL and reduced in the presence of the tricyclic antidepressant DIP. A parallel trend was observed in norepinephrine (NE)-induced [14C]tryptophan metabolism in the pineal culture medium. All three drugs tested brought about further enhancement of NE-induced synthesis of MT; HAL produced an elevated, but DIP a reduced, level of [14C]5-HT, compared to the NE-induced value.
Animals↗
Accentuated response to raw soya-bean meal by meal feeding.
Diets containing raw soya-beans (RSD) when fed ad libitum cause reduction in growth rate and food utilization, enlargement of the pancreas and increase of its enzyme synthesis. A single meal of raw soya-beans with corn (1:9), tube-fed to geese, caused about 90% mortality, while geese, tube-fed with corn alone, did not show any negative response. No mortality occurred when geese were fed a similar diet ad libitum. Two-week old chicks were fed ad libitum or by tube, twice a day, similar amounts of RSD or heated soya-bean diet (HSD). While the chicks tube-fed HSD behaved similarly to those feeding freely, the chicks tube-fed RSD collapsed after one week. The thymus and bursa of fabricii were atrophied in the RSD tube-fed chicks. Diets containing increasing amounts of raw soya-bean meal (0,20%, 42%, and 80%) were fed freely to weanling rats or as one 4 h meal per day. All the rats fed the 4 h meal containing either 42% or 80% raw soya-bean meal died within 3 days; all the others survived. The rats were trained to meal-feeding by gradual reduction of their access to food. The negative effects of the RSD, i.e. reduced food intake and body weight gain, pancreas enlargement, were much more pronounced in the meal-fed rats than in those fed ad libitum. The differences increased by increasing dietary trypsin inhibitor (TI) (raw soya-bean meal).
Animal Feed↗
The pineal and endocrine changes in heat exposed male hamsters.
Decreased testicular weight with damaged seminiferous tubules were observed in hamsters pinealectomized and exposed continuously to high ambient temperature. In hamsters with intact pineals, exposure to heat resulted in reduced testicular weight without recognizable histological damage. In both groups, serum testosterone levels were elevated, evidently through a compensatory mechanism in the interstitial cells, which did not appear to be damaged. Concomitantly with these findings, reduced serum LH, and pituitary LH and prolactin concentrations were encountered in the heat-exposed pinealectomized hamsters, compared to those of their heat-exposed sham-operated counterparts. These results in hamsters reaffirm a previous postulation of a moderating, protective role for the pineal, against adverse effects of prolonged exposure to heat, in rodents.
Acclimatization↗
Cytochemical evaluation of anionic sites on the surface of cultured pigment epithelium cells from normal and dystrophic RCS rats.
Anionic sites on the surface of cultured pigment epithelium cells from normal and dystrophic rats were studied. Cytochemical procedures and quantitative analysis were employed in order to determine distribution patterns and labeling densities. Anionic sites, in general, were localized with cationized ferritin at pH 7.0. The presence and density of sialic acid residues on the pigment epithelium cell surface were evaluated with colloidal iron at pH 1.8. Dystrophic cells contained 20% more cationized ferritin-binding sites as compared with normal pigment epithelium cells. With colloidal iron, an 18% increase in labeling density was measured in dystrophic pigment epithelium cells. Pretreatment with neuraminidase reduced subsequent labeling with colloidal iron by 93-97%. Thus, the presence of sialic acid residues on the surface of pigment epithelium cells and a significant increase in its content on the surface of dystrophic cells were established.
Animals↗
The role of the pineal gland in thermoregulation in male hamsters.
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Adipose Tissue, Brown↗
Protein, essential amino acids and glycine requirements of the growing gosling (Anser cireneus).
The dietary requirements for protein and amino acids of the growing gosling (0-7 weeks) were calculated according to body composition, maintenance needs and the absorption rate of amino acids from feeds. The diets were formulated by least-cost linear programming, using the calculated requirements for amino acids, with or without minimal glycine + serine requirements. The diets formulated without minimal requirements of glycine + serine were supplemented with various amounts of glycine, and fed to growing goslings. The calculated requirements for protein and essential amino acids were lower than those suggested for growing broilers and turkeys. The requirements (g/MJ metabolizable energy) at 0-2, 2-4 and 4-7 weeks of age respectively, were: lysine 0.88, 0.48, 0.43; methionine + cystine 0.48, 0.38, 0.29; protein 14.5, 9.3, 7.6. The goslings did not respond to glycine supplementation of the diet.
Amino Acids, Essential↗
Effect of intermittent feeding on blood plasma growth hormone and prolactin in chickens of a heavy breed.
1. Variations in plasma growth hormone (GH) and prolactin concentrations were determined during growth (at 20, 33, 56 and 83 d of age) in ad libitum (control) and intermittently (alternate days) fed chicks. 2. In each group of birds the concentration of plasma GH was inversely related to age. The mean prolactin concentration was highest in the youngest (20-d-old) birds. 3. The concentration of plasma GH in the intermittently-fed birds deprived of food for 24 h (depleted birds) was significantly higher than that in the controls at 33, 56 and 83 d of age. The mean GH concentration in the intermittently-fed birds 24 h after refeeding (repleted birds) was less than that in the depleted ones. 4. The overall mean concentration of plasma prolactin in the depleted birds was significantly less than that in the control and repleted birds. 5. These results are consistent with the effects of fasting on GH and prolactin secretion and demonstrate that growth retardation in the intermittently-fed birds was not due to impaired GH secretion.
Age Factors↗
Effect of pinealectomy on heat-induced endocrine changes in female rats.
Exposure of pinealectomized rats to high ambient temperature (35 degrees C; PXH) brought about a diminution in pituitary weight and LH content when compared to their sham-operated peers (35 degrees C) or to pinealectomized controls (22 degrees C). Serum corticosterone level of PXH rats was significantly depressed while heat or pinealectomy alone had no effect. Mean oestrous cycle length was prolonged and blood serum progesterone was increased in the heat-exposed rats. However, the extended oestrous cycles and elevated serum progesterone levels of heat-exposed rats were depressed or abolished by pineal ablation. Thus, the pineal appears to exert a moderating effect on heat-induced endocrine changes in female rats. No changes were noticed in uterine and ovarian weights corrected for body weights either on the day of vaginal opening, at occurrence of the oestrous phase expressed as percentage of total oestrous cycle, or in N-acetyltransferase and hydroxyindole-O-methyltransferase activities.
Animals↗
Scanning electron microscopy of human Fallopian tube in ectopic pregnancy.
The scanning electron microscopy by virtue of its high resolution topographic reproduction of epithelial surfaces lining the female genital tract, provides unique information toward understanding the anatomy and physiology of the female reproductive system. The human Fallopian ectopic pregnancy is an urgent gynecologic event, which was and still is a diagnostic challenge. There is an increase in the incidence of ectopic pregnancy in recent years. With the purpose of exploring the etiology of tubal ectopic pregnancy from the ultrastructure point of view, we examined 7 cases of tubal pregnancy and compared them to a similar number of normal tubes. We do not find evidence to the pathophysiology of tubal pregnancy by examination of the ultrastructure of the human tube with scanning electron microscopy.
Epithelium↗
Localization of antibody binding sites in ultrathin sections of unembedded frog retinal tissue.
Much ultrastructural detail is retained in tissue fixed only with aldehydes and subsequently air-dried after suspension in a polyvinyl acetate emulsion. The latter provides an external support only, but permits ultrathin sectioning; thus, an exposure of intracellular contents for potential immunocytochemical reactions is achieved. Sections of unembedded frog retina so prepared have been studied with success. The tissue was incubated first with a rabbit antiserum prepared against gradient purified bovine rod outer segments. Following incubation, reacted sites were labeled with ferritin-conjugated goat anti-rabbit IgG and stained with phosphotungstic acid. Intense labeling of the rod outer segments was clearly achieved, whereas the cone outer segments were without label. Other parts of the retina, including the ellipsoid region of both rods and cones, were also without significant label. These regions provided an intrinsic control for the specificity of the antiserum and established the validity of the general technique.
Animals↗
Differential distribution of opsin in the plasma membrane of frog photoreceptors: an immunocytochemical study.
Opsin molecules on the surface of frog photoreceptors were visualized by immunocytochemistry at the ultrastructural level. Isolated retinas were immersed in biotinyl-antibody to bovine opsin followed by avidin-ferritin conjugates. Anti-opsin bound to the plasma membrane and to the surface of the most basal discs of red rod outer segments. Inner segment plasma membranes of red rod photoreceptors were devoid of anti-opsin label except for the apical plasma membrane in the region of the recently described periciliary ridge complex. The connecting cilium surface from its base at the periciliary region to the site of new disc evagination was almost free of anti-opsin binding, an observation in consonance with prior studies of thin sectioned retinas embedded in glutaraldehyde cross-linked bovine serum albumin. These results indicate that the continuous plasma membrane of photoreceptors is highly polarized. Opsin, which is free to diffuse throughout the outer segment plasma membrane and along the discs, does not back-diffuse onto the inner segment plasma membrane. The periciliary ridge complex and the base of the connecting cilium are possible sites of restriction of opsin mobility. This study also has provided new insight into the molecular structure of frog visual pigments. Frog green rod and cone outer and inner segment plasma membranes were not labeled by this sheep antiserum to bovine opsin. In contrast, discs of green ROS and the lamellae of some cones were labeled when these antibodies were applied to albumin embedded thin sections of frog retinas. Apparently, only internal or intramembraneous domains of green ROS and cone visual pigments were recognized by this antibody while both internal and extracellular domain(s) of red ROS opsin were reactive.
Animals↗
Asteroid bodies--an ultrastructural study.
An ultrastructural study of asteroid bodies in a vitreous aspirate from a patient suffering visual loss as a result of asteroid hyalosis is presented. Under appropriate conditions of fixation and high resolution transmission electron microscopy, a lamellar arrangement with a periodicity of 4.6 nm was observed. This lamellar arrangement is typical of liquid crystalline phases of lipids in water. X-ray micro-analysis confirmed the presence of calcium and phosphorus in the asteroid bodies. We propose that the asteroid bodies are not true crystals but rather liquid crystals of phospholipids in the vitreous humor.
Aged↗
Clinical trials in Israel. Criteria for approval.
Approval by the Ministry of Health is required prior to the use in man of any chemical compound, including recognized drugs that have not been registered for marketing in Israel. As a rule, drugs are permitted for use in experimental treatment of human beings only after they have been thoroughly tested in animals and when a justified rationale has been provided. General outlines regarding required animal tests are available. Indications other than those for which a drug has been registered or dosages several times exceeding those recommended are dealth with as new compounds. Only physicians licensed in Israel may apply for permission to perform clinical trials. The responsibility for conducting a trial lies with the experimenting physician and the institution under whose auspices the study is carried out. Further principles concerning clinical trials in Israel include such issues as: 1) What type of basic information (rationale, safety, quality, etc.) must be provided before approval is granted? 2) Which population groups should in principle be excluded from human experimentation? 3) Should clinical trials be restricted to those for whom therapy may be directly beneficial? A number of clinical trials considered in the past by the Ministry's Committee illustrate the Israeli approach to clinical trials.
Clinical Trials as Topic↗