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Biomedical subjects

S Kiss

Publications and source records attributed to S Kiss.

At least 19 recordsLinked to original sources
PubMed2006

The dangers of intraosseous fibrosing agent injection in the treatment of bone cysts. The origin of major complications shown in a rabbit model.

Direct intraosseous injection of fibrosing agent is widely used in the treatment of aneurysmal bone cysts. The purpose of this study was to evaluate the consequences of fibrosing agent penetrating the medulla of bones. This may be the case when, by mistake, the fibrosing agent is administered into the medulla or when the wall of the cyst ruptures and fibrosing agent is able to drift into the medulla. Twelve rabbits were injected transcutaneously with a fibrosing agent directly into the proximal metaphysis of the tibia. Prior to injection 0.5 ml of liquid-like, bloody, intraosseal tissue was aspirated, then 0.5 ml of fibrosing agent was administered. Fibrosing agent was introduced slowly (20 s) to avoid overpressure. Nine rabbits (75%) died within minutes after the introduction of fibrosing agent. A full body roentgenogram was taken of each rabbit and the animals that died underwent autopsy to find the exact cause of death. Roentgenograms of the chest showed massive multiple pulmonary emboli confirmed in all lethal cases by the autopsy. This animal model was created to draw attention to the dangers of any leakage of the fibrosing agent into the medulla of bones.

Animals↗
PubMed2006

Relative ability of young and mature muscles to respond to limb lengthening.

The response of the muscle is critical in determining the functional outcome of limb lengthening. We hypothesised that muscle response would vary with age and therefore studied the response of the muscles during tibial lengthening in ten young and ten mature rabbits. A bromodeoxyuridine technique was used to identify the dividing cells. The young rabbits demonstrated a significantly greater proliferative response to the distraction stimulus than the mature ones. This was particularly pronounced at the myotendinous junction, but was also evident within the muscle belly. Younger muscle adapted better to lengthening, suggesting that in patients in whom a large degree of muscle lengthening is required it may be beneficial to carry out this procedure when they are young, in order to achieve the optimal functional result.

Aging↗
PubMed2003

Feline interstitial cystitis results in mechanical hypersensitivity and altered ATP release from bladder urothelium.

ATP can be released from a variety of cell types by mechanical stimulation; however, the mechanism for this release and the influence of pathology are not well understood. The present study examined intracellular signaling mechanisms involved in swelling-evoked (exposure to a hypotonic solution) release of ATP in urothelial cells from normal cats and cats diagnosed with interstitial cystitis (feline interstitial cystitis; FIC). Using the luciferin-luciferase bioluminescent assay, we demonstrate that swelling-evoked ATP release is significantly elevated in FIC cells. In both normal and FIC cells, ATP release was significantly decreased (mean 70% decrease) by application of blockers of stretch-activated channels (amiloride or gadolinium), as well as brefeldin A and monensin (mean 90% decrease), suggesting that ATP release occurs when ATP-containing vesicles fuse with the plasma membrane. Swelling-evoked release was reduced after removal of external calcium (65%), and release was blocked by incubation with BAPTA-AM or agents that interfere with internal calcium stores (caffeine, ryanodine, heparin, or 2-aminoethoxydiphenyl borate). In addition, agents known to act through inositol 1,4,5-triphosphate (IP3) receptors (thapsigargin, acetylcholine) release significantly more ATP in FIC compared with normal urothelium. Taken together, these results suggest that FIC results in a novel hypersensitivity to mechanical stimuli that may involve alterations in IP3-sensitive pathways.

Adenosine Triphosphate↗
PubMed2003

COX-2 dependent inflammation increases spinal Fos expression during rodent postoperative ileus.

BACKGROUND AND AIMS: Cyclooxygenase 2 (COX-2) and prostaglandins (PGs) participate in the pathogenesis of inflammatory postoperative ileus. We sought to determine whether the emerging neuronal modulator COX-2 plays a significant role in primary afferent activation during postoperative ileus using spinal Fos expression as a marker. METHODS: Rats, and COX-2(+/+) and COX-2(-/-) mice underwent simple intestinal manipulation. The effect of intestinal manipulation on Fos immunoreactivity (IR) in the L(5)-S(1) spinal cord, in situ circumference, and postoperative leucocytic infiltrate of the intestinal muscularis was measured. Postoperative PGE(2) production was measured in peritoneal lavage fluid. The dependence of these parameters on COX-2 was studied in pharmacological (DFU, Merck- Frosst, selective COX-2 inhibitor) and genetic (COX-2(-/-) mice) models. RESULTS: Postoperative Fos IR increased 3.7-fold in rats and 2.2-fold in mice. Both muscularis leucocytic infiltrate and the circumference of the muscularis increased significantly in rats and COX-2(+/+) mice postoperatively, indicating dilating ileus. Surgical manipulation markedly increased PGE(2) levels in the peritoneal cavity. DFU pretreatment and the genetic absence of COX-2(-/-) prevented dilating ileus, and leucocytic infiltrate was diminished by 40% with DFU and by 54% in COX-2(-/-) mice. DFU reversed postsurgical intra- abdominal PGE(2) levels to normal. Fos IR after intestinal manipulation was attenuated by approximately 50% in DFU treated rats and in COX-2(-/-) mice. CONCLUSIONS: Postoperatively, small bowel manipulation causes a significant and prolonged increase in spinal Fos expression, suggesting prolonged primary afferent activation. COX-2 plays a key role in this response. This activation of primary afferents may subsequently initiate inhibitory motor reflexes to the gut, contributing to postoperative ileus.

Animals↗
PubMed2002

Altered urinary bladder function in mice lacking the vanilloid receptor TRPV1.

In the urinary bladder, the capsaicin-gated ion channel TRPV1 is expressed both within afferent nerve terminals and within the epithelial cells that line the bladder lumen. To determine the significance of this expression pattern, we analyzed bladder function in mice lacking TRPV1. Compared with wild-type littermates, trpv1(-/-) mice had a higher frequency of low-amplitude, non-voiding bladder contractions. This alteration was accompanied by reductions in both spinal cord signaling and reflex voiding during bladder filling (under anesthesia). In vitro, stretch-evoked ATP release and membrane capacitance changes were diminished in bladders excised from trpv1(-/-) mice, as was hypoosmolality-evoked ATP release from cultured trpv1(-/-) urothelial cells. These findings indicate that TRPV1 participates in normal bladder function and is essential for normal mechanically evoked purinergic signaling by the urothelium.

Acetic Acid↗
PubMed2001

Impaired response to chemical irritation of the urinary tract in mice with disruption of the preprotachykinin gene.

Previous studies demonstrated that acute irritation of the lower urinary tract (LUT) induces the expression of the immediate early gene, c-fos, in lumbo-sacral spinal cord neurons "J. Neurosci. 12 (1992) 4878" "Am. J. Physiol. 265 (1993) 326" "Somatosens. Mot. Res. 15 (1998) 5". This effect was mediated in part by activation of capsaicin-sensitive bladder afferents "Am. J. Physiol. 265 (1993) 326". Here we investigate the role of preprotachykinin gene products (neurokinin A and substance P) in the response to bladder irritation in urethane-anesthetized mice. Acute irritation of the LUT (intravesical acetic acid) induced smaller numbers of Fos-positive neurons in the spinal cord of mice with a mutated preprotachykinin gene than in wild type mice. Increased Fos expression following LUT irritation or a sham operation in wild type mice was also significantly reduced by pretreatment with the NK2 antagonist, MEN 11420, but Fos expression in mutant mice was not altered by the antagonist. During cystometrograms, a significantly higher percentage (83%) of mutant mice exhibited urinary retention and overflow incontinence as compared to wild type controls. These findings suggest an involvement of tachykinins and NK2 receptors in the response to chemical irritation of the LUT in mice and also suggest that tachykinins contribute to the regulation of normal reflex bladder activity.

Acetic Acid↗
PubMed2001

Dehydroascorbic acid, a blood-brain barrier transportable form of vitamin C, mediates potent cerebroprotection in experimental stroke.

Neuronal injury in ischemic stroke is partly mediated by cytotoxic reactive oxygen species. Although the antioxidant ascorbic acid (AA) or vitamin C does not penetrate the blood-brain barrier (BBB), its oxidized form, dehydroascorbic acid (DHA), enters the brain by means of facilitative transport. We hypothesized that i.v. DHA would improve outcome after stroke because of its ability to cross the BBB and augment brain antioxidant levels. Reversible or permanent focal cerebral ischemia was created by intraluminal middle cerebral artery occlusion in mice treated with vehicle, AA, or DHA (40, 250, or 500 mg/kg), either before or after ischemia. Given before ischemia, DHA caused dose-dependent increases in postreperfusion cerebral blood flow, with reductions in neurological deficit and mortality. In reperfused cerebral ischemia, mean infarct volume was reduced from 53% and 59% in vehicle- and AA-treated animals, respectively, to 15% in 250 mg/kg DHA-treated animals (P < 0.05). Similar significant reductions occurred in nonreperfused cerebral ischemia. Delayed postischemic DHA administration after 15 min or 3 h also mediated improved outcomes. DHA (250 mg/kg or 500 mg/kg) administered at 3 h postischemia reduced infarct volume by 6- to 9-fold, to only 5% with the highest DHA dose (P < 0.05). In contrast, AA had no effect on infarct volumes, mortality, or neurological deficits. No differences in the incidence of intracerebral hemorrhage occurred. Unlike exogenous AA, DHA confers in vivo, dose-dependent neuroprotection in reperfused and nonreperfused cerebral ischemia at clinically relevant times. As a naturally occurring interconvertible form of AA with BBB permeability, DHA represents a promising pharmacological therapy for stroke based on its effects in this model of cerebral ischemia.

Animals↗
PubMed2001

Elevation of soluble intercellular adhesion molecule-1 levels in symptomatic and asymptomatic carotid atherosclerosis.

OBJECTIVE: Recent data suggest that the increased expression of intercellular adhesion molecule-1 (ICAM-1) in atherosclerotic plaque taken from the carotid bifurcation correlates with the development of neurological symptoms. As a result, the authors sought to compare the serum levels of soluble forms of ICAM-1 (sICAM-1) in patients who were asymptomatic with those who were symptomatic for carotid artery stenosis as well as in patients who were matched in terms of sex, age, and risk factors who did not have carotid artery disease. METHODS: Using enzyme-linked immunosorbent assay, serum sICAM-1 levels were prospectively determined in 54 patients scheduled to undergo carotid endarterectomy for either symptomatic or asymptomatic high-grade stenosis (> or =60%) and in 5 additional patient controls. Data are expressed as mean +/- standard error of the mean, with significance defined as P < 0.05 using the Mann-Whitney two-tailed test for two-column comparison or analysis of variance and Fisher protected least significant difference test. RESULTS: Using a univariate model, serum sICAM-1 levels were significantly elevated in patients with carotid artery stenosis as compared with control patients without stenosis (347 +/- 15 ng/ml versus 216 +/- 8.2 ng/ml) (P < 0.01). When the asymptomatic and symptomatic patients with carotid artery stenosis were considered separately, these levels were still elevated relative to those of control patients (asymptomatic [312 +/- 18 ng/ml] and symptomatic [376 +/- 22 ng/ml] patients; P = 0.06 for asymptomatic versus control patients, P < 0.01 for symptomatic versus control patients). Symptomatic patients also had significantly elevated sICAM-1 levels as compared with asymptomatic patients (P < 0.05). Despite the fact that female patients demonstrated higher ICAM-1 levels than male patients (P < 0.05), sex, age, and risk factors such as the presence of hypercholesterolemia, diabetes, hypertension, or a history of smoking did not confound these findings. CONCLUSION: Levels of sICAM-1 are higher in patients with carotid stenosis than in control patients. Symptomatic patients demonstrate significantly elevated levels as compared with asymptomatic patients. These data support the contention that ICAM-1 is a reliable marker of carotid disease progression and suggest that serum levels may be useful in following certain asymptomatic patients.

Aged↗
PubMed2000

Long-term oscillation of corticosterone following intermittent cocaine.

We have shown that repeated administration of cocaine, as well as other drugs and nondrug stressors, can induce alternating increases and decreases in several neurotransmitter and endocrine endpoints, which we call oscillation. Oscillation studies have typically used 3-4 pretreatments with cocaine or other agents, raising the question of whether oscillation lasts beyond this point. Using plasma corticosterone as our endpoint measure, we therefore inquired whether oscillation would persist across eight administrations of cocaine over a 28-day period. We report oscillation of corticosterone levels persisting across all eight cocaine groups. Our data also indicate that the degree of oscillation increases with the intertreatment interval.

Animals↗
PubMed2000

Postischemic cerebrovascular E-selectin expression mediates tissue injury in murine stroke.

BACKGROUND AND PURPOSE: Although the deleterious role of several proinflammatory mediators, including P-selectin, in reperfused stroke is well established, the role of E-selectin has not been fully characterized. METHODS: E-selectin mRNA expression was studied at 4, 10, and 24 hours after reperfusion with reverse transcription and polymerase chain reaction in mice (n=18) subjected to transient intraluminal middle cerebral artery occlusion (MCAO). Mice received intravenous injection with anti-E-selectin monoclonal antibody (10, 35, or 50 microg), nonimmune IgG, or vehicle immediately before MCAO and 90 minutes later (n=85). Others received anti-E-selectin antibody 3 or 6 hours after MCAO (n=32). Myeloperoxidase activity was measured in sham-operated mice and after 10 hours of reperfusion in saline-, nonimmune IgG-, or anti-E-selectin IgG-treated cohorts (n=17). Serial cerebral blood flow was measured with laser-Doppler flowmetry, and outcomes were assessed by neurological deficits and infarct volumes with the use of planimetric analysis of triphenyltetrazolium chloride-stained sections. RESULTS: Upregulated E-selectin expression occurred in the ischemic cerebral vasculature within 4 hours of reperfusion and persisted for 24 hours. Anti-E-selectin antibody increased ischemic cortical cerebral blood flow up to 2.6-fold (P:<0.05). In addition to dose-dependent reductions in neurological deficits (P:<0.05), mortality, and infarct volumes (P:<0.01 for 35 and 50 microg), anti-E-selectin treatment reduced cerebral neutrophil accumulation (P:<0.05) and was neuroprotective even if delayed until 3 hours after ischemia (P:<0. 05). CONCLUSIONS: These findings establish a functional role for E-selectin in the pathogenesis of tissue injury after cerebral ischemia and reperfusion and suggest that E-selectin blockade may be clinically useful in the treatment of reperfused stroke.

Animals↗
PubMed1999

Warthin-like tumor of the thyroid a case report.

A case of Warthin-like tumor of the thyroid (WaLTT) with cervical lymph node metastasis is presented. The problems of the FNA diagnosis of this type of tumor is discussed as well as the histogenesis, nature and behaviour of this peculiar tumor.

Adenolymphoma↗
PubMed1998

[Abdominal trans-sphincter resection of the anus: new possibilities in the surgical management of deep rectal cancer, with preservation of the anal sphincter].

The last decade has brought marked changes in the surgical treatment of rectal cancer: as the indication of the sphincter-saving procedures was extended, the rate of the abdomino-perineal excision has decreased even in the case of tumours of the distal third of the rectum. However, even with the use of the modern stapling devices, the anterior resection and colo-anal anastomosis may not always be feasible by the traditional abdominal approach. In these cases the sphincter-saving resection can be performed by a particular approach, the abdomino-transsphincteric technique. The authors present this seldom used operation. From the 1-st of January 1994 to the 31-st of August 1996 14 abdomino-transsphincteric resections have been performed. The mean age of the patients was 62.2 (38-81) years. The lower edge of the tumours was situated at 6.3 (5-8) cm from the anal verge. The anastomosis was performed by the double stapling technique in 8 and by hand suture in 6 cases, its distance from the anal verge was 3.2 (3-4) cm. A colon J-pouch was used in 3 cases and a diverting colostomy was performed routinely. One patient died in the postoperative period and a reoperation (abdomino-perineal excission) was performed because of left colon necrosis: Anastomotic leakage was observed in one case. By the time of the present study, 11 patients have had their colostomies closed. The continence is acceptable in every case and all the patients experience a better subjective quality of life, than it was while wearing the colostomy. The use of this technique has helped to avoid a permanent colostomy in 21 out of 33 cases operated on for cancer of the distal rectal third in the reviewed period.

Abdomen↗
PubMed1998

The effects of lithium on a potential cycling model of bipolar disorder.

1. Although bipolar disorder constitutes a major public health problem, with a high risk of suicide and an economic cost exceeding that of unipolar depression, it has received comparatively little attention, particularly at the basic science level. Perhaps as a result of this neglect, there is currently no animal model able to simulate the cyclicity which is its defining characteristic. 2. Consequently, drug development in this area is meager and has proceeded serendipitously rather than empirically. 3. The authors have recently reported that repeated exposure to cocaine and other stressors can induce an oscillation or cycling in a host of neurochemical and physiological systems. 4. In order to test whether such cycling might be of potential relevance to bipolar disorder, the authors examined whether cocaine-induced cyclicity of amphetamine-evoked efflux of dopamine from slices of rat nucleus accumbens and striatum and/or cocaine induced oscillation of a behavior, stress-induced hypoalgesia, could be prevented by lithium, the agent of choice in treating this disease. 5. The authors report that prophylactic treatment with lithium, completely and specifically prevented oscillations in each instance. This may represent an important initial step toward the development of the first cycling model of bipolar disorder.

Amphetamine↗
PubMed1997

Seasonal variations in manifestations and activity of systemic lupus erythematosus.

The purpose of the present study was to investigate a possible seasonal pattern in various clinical and laboratory manifestations in a group of systemic lupus erythamatosus (SLE) patients. One hundred and five SLE patients were followed up during a 4 yr period. Data on each of the clinical and laboratory variables examined, as well as the results of the disease activity index (SLEDAI), were plotted against the month during which they were obtained. Photosensitivity was the only variable to show a seasonal pattern, having higher scores during the summer months (1.04 +/- 0.16 in July vs 0.58 +/- 0.12 in December). We were unable to show seasonal patterns in any of the other variables examined. As a group, SLE patients do not show any significant seasonal pattern in disease manifestations and activity, except for photosensitivity. However, such a pattern may exist for the individual patient.

Adolescent↗
PubMed1997

Vertebrate development in the environment of space: models, mechanisms, and use of the medaka.

With the advent of space travel, it is of immediate interest and importance to study the effects of exposure to various aspects of the altered environment of space, including microgravity, on Earth-based life forms. Initial studies of space travel have focused primarily on the short-term effects of radiation and microgravity on adult organisms. However, with the potential for increased lengths of time in space, it is critical to now address the effects of space on all phases of an organism's life cycle, from embryogenesis to post-natal development to reproduction. It is already possible for certain species to undergo multiple generations within the confines of the Mir Space Station. The possibility now exists for scientists to consider the consequences of even potentially subtle defects in development through multiple phases of an organism's life cycle, or even through multiple generations. In this discussion, we highlight a few of the salient observations on the effects of the space environment on vertebrate development and reproductive function. We discuss some of the many unanswered questions, in particular, in the context of the choice of appropriate models in which to address these questions, as well as an assessment of the availability of hardware already existing or under development which would be useful in addressing these questions.

Animals↗