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Biomedical subjects

S Kantor

Publications and source records attributed to S Kantor.

At least 19 recordsLinked to original sources
PubMed2001

8-OH-DPAT and MK-801 affect epileptic activity independently of vigilance.

Vigilance and parallel occurrence of epileptic activity after administration of the 5-HT(1A) agonist 8-OH-DPAT and the NMDA receptor antagonist MK-801 were studied in the genetic absence epilepsy model WAG/Rij rats. Spike-wave discharges (SWD) were present predominantly in passive awake and light slow wave sleep (SWS1) either in control animals or after treatments. Injection of 8-OH-DPAT (20.0 microg/rat i.c.v.) caused marked increase and MK-801 (10.0 microg/rat i.c.v.) decrease in SWD densities, thus the ratios of SWD in passive awake and in SWS1. SWD densities of MK-801 plus 8-OH-DPAT in combination were similar to those of CSF+CSF treated control rats. Both 8-OH-DPAT and MK-801 transiently increased the duration of active awake, increased latency and decreased duration of rapid eye movement (REM) sleep. 8-OH-DPAT increased the amount of SWD despite the decrease in the duration of SWS1. MK-801 decreased the amount of SWD despite the lack of significant change in duration of passive awake or SWS1. Pre-treatment with MK-801 reversed 8-OH-DPAT- induced increase in duration of SWD without any effect on 8-OH-DPAT-induced changes in sleep parameters. Our studies provide evidence that 8-OH-DPAT-induced epileptic activity is independent of its effect on sleep, and that interaction of serotonergic and glutamatergic systems plays a role in the generation of SWD, but not in the regulation of vigilance and sleep.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2001

Enhancement of bone growth into porous intramedullary implants using non-invasive low intensity ultrasound.

An in vivo study was designed to determine if non-invasive low intensity ultrasound could enhance bone growth into porous intramedullary implants. Fully porous intramedullary rods were implanted bilaterally into the ulnae of six dogs. In each dog, one ulna served as a control and the other was treated with 20 min of daily ultrasound stimulation for 6 consecutive weeks. Analysis of serial transverse sections indicated an average of 119% more bone growth into the ultrasound-treated implants compared with the contralateral controls (P < 0.001). In each of the 6 dogs, there was a significantly greater amount of bone ingrowth on the ultrasound-stimulated side. These data indicate a clear potential for externally applied ultrasound therapy to augment biological fixation.

Animals↗
PubMed2001

Rapid desensitization of 5-HT(1A) receptors in Fawn-Hooded rats after chronic fluoxetine treatment.

Anxiety, platelet serotonin (5-HT) content and functions of the 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) were measured in Sprague--Dawley (SD) and Fawn-Hooded (FH) rats, a strain with genetically impaired 5-HT storage and reuptake system and a putative model of depression and anxiety. In addition, the effects of 7 and 16 days treatment with the selective serotonin reuptake inhibitor (SSRI) fluoxetine on 8-OH-DPAT-induced responses were studied. FH rats showed significantly higher anxiety in the social interaction test, and much lower platelet 5-HT content compared to SD rats. The efficacy of 8-OH-DPAT (15-120 microg/kg, i.v.) to induce lower lip retraction (an effect mediated by median raphe receptors) was increased in FH rats. In most FH but only a few SD rats a special neurological syndrome, clonic movement of the masseters and in-and-out movement of the eyeballs, was induced by 8-OH-DPAT, and this behaviour like other effects of 8-OH-DPAT, was completely blocked by pretreatment with the 5-HT(1A) receptor antagonist WAY-100635. In SD rats fluoxetine (10 mg/kg/day, i.p.) caused a moderate inhibition of 8-OH-DPAT-induced hypothermia, an effect mediated most likely by hypothalamic 5-HT(1A) receptors, (-19% and -40% after 7 and 16 days of fluoxetine, 24 h after the last injection, respectively). In FH rats fluoxetine caused a rapid and complete reduction in the 8-OH-DPAT-induced hypothermia (-65% and -91% after 7 and 16 days of fluoxetine, respectively). Fluoxetine caused no change in lower lip retraction but a reduction in the masseter-eyeball syndrome in both SD and FH rats. Our data provide evidence that in FH rats, median raphe 5-HT(1A) receptors are hypersensitive, and the hypothalamic 5-HT(1A) receptor desensitization, caused by SSRI antidepressants, is faster and more complete. These data support the notion that chronic treatment with SSRIs induces a desensitization of some 5-HT(1A) receptor populations, and impaired 5-HT storage and reuptake may accelerate this process.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2001

Anxiety-like effects induced by acute fluoxetine, sertraline or m-CPP treatment are reversed by pretreatment with the 5-HT2C receptor antagonist SB-242084 but not the 5-HT1A receptor antagonist WAY-100635.

The possible role of 5-HT1A and 5-HT2C receptors in the anxiety induced by fear, acute treatment with SSRI antidepressants or the 5-HT receptor agonist m-CPP were tested in the social interaction anxiety test in male Sprague-Dawley rats. Fluoxetine (2.5-10 mg/kg, i.p.), sertraline (15 mg/kg, i.p.) and m-CPP (0.5-2.0 mg/kg, i.p.) all had an anxiogenic-like profile (decrease in time of total social interaction and increase in self-grooming compared to vehicle) under low-light, familiar arena test conditions. All these effects were reversed by pretreatment with the highly subtype-selective 5-HT2C receptor antagonist, SB-242084 at doses of either 0.05 or 0.2 mg/kg, i.p. In contrast, the selective 5-HT1A receptor antagonist WAY-100635 (0.05 and 0.2 mg/kg, s.c.) failed to reverse SSRI-induced decrease in time of total social interaction, further, it augmented self-grooming response. SB-242084 (0.2 mg/kg) and WAY-100635 (0.05 and 0.2 mg/kg) reversed hypolocomotion caused by the SSRI antidepressants. SB-242084, tested alone against vehicle under high-light, unfamiliar arena test conditions associated with fear, caused significant anxiolysis at 0.2 mg/kg and higher doses. These results suggest that increased anxiety in rodents, and possibly, also in humans (e.g. agitation or jitteriness after SSRIs and panic after m-CPP), caused by acute administration of SSRI antidepressants or m-CPP, are mediated by activation of 5-HT2C receptors. Blockade of 5-HT1A autoreceptors may exacerbate certain acute adverse effects of SSRI antidepressants. Both 5-HT1A and 5-HT2C receptors are involved in the SSRI-induced decrease in locomotor activity. In addition, our studies confirm data that subtype-selective 5-HT2C receptor antagonists have strong anxiolytic actions.

Aminopyridines↗
PubMed2001

Femoral remodeling after porous-coated total hip arthroplasty with and without hydroxyapatite-tricalcium phosphate coating: a prospective randomized trial.

We prospectively assessed femoral bone remodeling using dual-energy x-ray absorptiometry for 2 years after total hip arthroplasty. Thirty-nine hips were randomized to receive a titanium proximally porous-coated femoral component with or without hydroxyapatite-tricalcium phosphate coating. Although both stems resulted in alterations in the periprosthetic bone mineral density, the hydroxyapatite-tricalcium phosphate coated stems had significantly less femoral bone loss than the uncoated stems at 2-year follow-up. This reduced femoral bone loss may provide short-term and long-term advantages over noncoated stems.

Absorptiometry, Photon↗
PubMed2001

Cervical osteophytes presenting as unilateral vocal fold paralysis and dysphagia.

Any process involving either the vagus nerve, its recurrent laryngeal branch or the external branch of the superior laryngeal nerve may cause paralysis of the vocal fold. The most common cause is neoplasm. Clinically, the patients often present with a hoarse, breathy voice as well as symptoms of aspiration. The following represents a unique case of unilateral vocal fold paralysis and dysphagia caused by a degenerative disease of the cervical spine, resluting in extrinsic compression of the recurrent laryngeal nerve.

Aged↗
PubMed2000

High social anxiety and low aggression in Fawn-Hooded rats.

The Fawn-Hooded (FH) rat strain, with well-documented changes in their serotonergic and noradrenergic systems, is a putative genetic model for some neuropsychiatric disorders like depression, alcohol abuse, and anxiety. Because social phobia frequently occurs in combination with these disorders and there are no social anxiety-related data in FH rats in the literature, we measured the behavior of FH rats in the social interaction test. In addition, the effects of the anxiogenic Serotonin-2C (5-HT2C) receptor agonist, m-chlorophenylpiperazine (m-CPP), were studied. Male FH, Wistar (W), and Sprague-Dawley (SD) rats were used in two different test conditions of the social interaction test: the high light, unfamiliar arena, associated with high anxiety, and the low light, familiar arena, associated with low anxiety-like behavior. All social behaviors were markedly diminished in FH rats that suggested higher anxiety in these animals. Total social interaction time was reduced by 60-70% in FH rats compared either to W or SD rats under high light, unfamiliar or low light, familiar conditions, respectively. Aggressive behavior was reduced at least by 85% in FH rats. Locomotor activity and exploratory behavior were only minimally, in most comparisons, not significantly affected in FH rats. Total social interaction time, aggression, and locomotor activity were decreased, and self-grooming increased by m-CPP (0.5 mg/kg, ip) in all three strains. m-CPP decreased total social interaction time thus, caused anxiety most efficiently in FH rats (reduced by 69%, 50%, and 55% in FH, W, and SD rats, respectively), but other effects of the drug were similar in the three strains. Our studies provide evidence that the FH rat strain may be a genetic model of social phobia or other anxiety disorders with impaired social behavior.

Aggression↗
PubMed1990

Simaomicin (LL-D42067), a novel antibiotic from Actinomadura madurae. I. Taxonomy, fermentation and biological activity.

A new antibacterial antibiotic, designated simaomicin alpha (LL-D42067 alpha) was isolated from the fermentation broth of an actinomycete strain. Based on cultural, physiological, morphological and chemical characteristics, culture LL-D42067 was identified as a new subspecies of Actinomadura madurae. Simaomicin alpha demonstrated potent activity against Gram-positive bacteria and was active in vivo against a variety of Eimeria species causing coccidiosis in chickens.

Animals↗
PubMed1990

In vivo effects of biosynthetic chicken growth hormone in broiler-strain chickens.

Two experiments were conducted to examine the effects of growth hormone (GH) in growing chickens older than broiler age. In experiment 1, 8 week old male (heavy "broiler" type strain) chickens received daily injections of either biosynthetic chicken GH or an implant of biosynthetic bovine GH for 3 weeks. Neither growth rate (daily weight gain) nor the feed:gain ratio was influenced by either preparation of GH. However, an increase in breast muscle was observed in birds receiving the higher dose (250 micrograms/kg/day) of chicken GH. No changes were observed with chicken GH treatment on the weights of the fat pad, heart, gizzard and shank bone or on shank bone length or on plasma concentrations of free fatty acids. Experiment 2 employed 12 week old male, heavy strain, chickens with biosynthetic chicken GH being administered via Alzet osmotic pumps. In this study, GH (50 micrograms/kg/day) increased growth rate, body weight, pectoralis (breast) muscle weight, adipose tissue weight, bursa Fabricius weight and the plasma concentrations of free fatty acids. It is concluded that GH can influence carcass composition and growth in older chickens.

Aging↗
PubMed1988

The effect of 13-cis retinoic acid on hematopoiesis in human long-term bone marrow culture.

The modulatory effect of 13-cis retinoic acid (RA) on the growth, differentiation and function of hematopoietic cells in human long-term cultures was studied. RA (5 X 10(-8) M) induced enhancement of myeloid progenitor cell growth in the non-adherent layer throughout 6 weeks of incubation while it did not affect the number of myeloid progenitors in the adherent layer. The vitamin did not alter the differentiation pattern of colony forming unit-culture (CFU-C). The addition of RA to cultures for 5 weeks did not alter the cellular composition of the adherent layer. Prolonged exposure of hematopoietic cells to RA did not affect the functional activity of neutrophils and macrophages, i.e. the cells were active in phagocytosing Candida albicans (CA).

Bone Marrow Cells↗
PubMed1984

CL 259,971: a potent new polyether anticoccidial. 1. Battery efficacy and safety.

The anticoccidial activity of CL 259,971, a new polyether ionophore produced by Actinomadura yumaense sp. nov, has been demonstrated against six species of poultry Eimeria, tested individually or in mixed species infections. Statistically significant activity was obtained against some species with as little as 2.5 ppm of drug. The optimal treatment level, however, was determined to be 5 ppm. At this level, performance was comparable to 100 or 120 ppm of monensin. CL 259,971 is coccidiocidal and affects the early asexual stages of the life cycle of E. tenella. Fed to uninoculated cockerels in batteries at 10 ppm for 7 weeks, CL 259,971 permitted numerically superior weight gains when compared with 200 ppm of monensin.

Animals↗
PubMed1984

CL 259,971: a potent new polyether anticoccidial. 2. Floor-pen trials.

Three floor-pen trials have confirmed the high anticoccidial activity of CL 259,971 as first reported in batteries. The optimal dosage level was shown to be 5 ppm in the diet. At this level, excellent anticoccidial activity was observed with no adverse effect on weight or performance. The results indicated that 5 ppm of CL 259,971 provided efficacy and performance comparable to arprinocid or monensin, which were used for comparison in these trials.

Adenine↗
PubMed1983

Percutaneous absorption, blood levels, and urinary excretion of resorcinol applied topically in humans.

The absorption and metabolic disposition of 2% resorcinol applied topically in a hydroalcoholic vehicle was determined in three human subjects. The drug penetrated the skin at a rate of 0.37 micrograms/cm2/hour. After 2 weeks of bid application of 800 mg resorcinol to about 30% of body surface of each subject, an average of 1.64% of the dosage was being excreted in 24-hour urine specimens as the glucuronide or as the sulfate conjugate. There was no resorcinol in blood drawn at weeks 1, 2, 3, and 4, or nor were there any abnormalities in thyroid function or blood chemistries at weeks 2, 3, and 4. Resorcinol (2%) appears safe for topical use in humans.

Administration, Topical↗
PubMed1980

Very low doses of radio-iodine for hyperthyroidism. Failure to prevent a high incidence of early hypothyroidism.

One hundred and fifty-one patients with hyperthyroidism were treated with varying doses of radio-iodine (131I), and the results were analysed 1 year later. Of the patients with Graves' disease who received the lowest 131I doses (mean 2,8 mCi) 39% had persistent thyrotoxicosis and 25% were hypothyroid 12 months after therapy. Moderate doses of 131I (mean 5,9 mCi) reduced the rate of persistent disease to 19% and increased the rate of hypothyroidism by only 4% (P less than 0,05). When 131I dosages were calculated according to thyroid weight (microCi/g), patients who received the lowest doses (mean 115 microCi/g) again had significant rates of both persistent hyperthyroidism (38%) and hypothyroidism (24%). These data indicate that very low doses of 131I in the treatment of Graves's disease may result in a high incidence of persistent disease, but do not necessarily result in a very low incidence of early hypothyroidism. Low-dose 131I regimens are unsuitable for treatment of thyrotoxicosis unless very good facilities for patient follow-up are available.

Adult↗
PubMed1978

Post-thyroidectomy thyrotoxicosis.

94 patients with postoperative recurrent hyperthyroidism were evaluated for duration of remission, goitre size, and response to radio-iodine (131I). 6 patients required 131I therapy within twelve months of operation--5 had large remnants because of inadequate surgery. 57% of patients relapsed within 5 years, but 16% relapsed after 20 years and 8% after more than 30 years. Estimated goitre weights ranged from 4 g to 65 g, and goitre size was unrelated to the duration of remission. All patients were treated with 131I. 23% of the patients became hypothyroid in the first postoperative year and 10% in the second year. The results indicate that postoperative thyrotoxicosis can recur decades after operation. Operation seems to sensitise the thyroid to the early effects of radiation by 131I.

Adult↗
PubMed1975

Relationship of pasture rotation to acquisition of gastrointestinal nematodes by sheep.

In a study of the relationship between pasture rotation in Illinois and acquisition of nematodes (mostly Haemonchus contortus) and body weight gains by lambs grazing with their ewes, 2 pasture rotation systems were tested. (1) Lambs and ewes were rotated through a series of 12 alfalfa-bromegrass-lespedeza pastures, each pasture being grazed for 3 to 4 days and rested for 5.5 weeks; 4 complete rotations were done during a 168-day grazing season. (2) Lambs and ewes were moved every 2 days, and 3 complete rotations of 50, 42, and 54 days, respectively, were done during the 146-day grazing season. The lambs under rotation had more nematodes and gained less weight than nonrotated control lambs, although rotation increased the amount of pasturage. Rotation is not recommended to control nematode parasitism of sheep in Illinois.

Animals↗