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T Horn

Publications and source records attributed to T Horn.

At least 109 records · Page 6Linked to original sources
PubMed1994

Lack of fever suppression or central AVP release in 1K1C hypertensive rats.

Previous studies from our laboratory showed a transient suppression of the febrile response to intracerebroventricular (i.c.v.) PGE1 in the one-kidney, one-clip (1K1C) model of hypertension. This may have been due to an enhanced vasopressinergic transmission since arginine vasopressin (AVP), acting within the central nervous system (CNS), is thought to mediate endogenous antipyresis. These initial experiments utilized a protocol for the induction of 1K1C hypertension which produced an initial rapid rise in blood pressure, evident by day 4 following surgery, with a corresponding inhibition of the febrile response. The present experiments utilized a more slowly developing 1K1C hypertension (evident by day 12 following surgery) to firstly attempt to determine if inhibition of the febrile response is due to the actual change in blood pressure or to neural signals arising from the clipped kidney, and secondly to determine if the concentration of AVP in push-pull perfusates of the ventral septal area (VSA) of pyrogen-treated sham-operated and 1K1C rats were altered. In urethane-anaesthetized rats, i.c.v. PGE2 evoked brisk monophasic fevers in both 1K1C and sham-operated animals, with no significant difference between fever heights. Consistent with this, we found no increase in immunoreactive AVP from perfusates of the VSA of 1K1C rats. These results suggest that there is no inhibition of the febrile response to PGE2 when a slower developing hypertension is induced, nor is there an elevated release of AVP into the VSA under our conditions. We conclude that a rapid increase in blood pressure, and not high blood pressure per se, is required to produce an inhibition of the febrile response.

Alprostadil↗
PubMed1994

Electromyographic activity of selected trunk and hip muscles during a squat lift. Effect of varying the lumbar posture.

Electromyographic (EMG) activity of selected hip and trunk muscles was recorded during a squat lift, and the effects of two different lumbar spine postures were examined. Seven muscles were analyzed: rectus abdominis (RA), abdominal obliques (AO), erector spinae (ES), latissimus dorsi (LD), gluteus maximus (GM), biceps femoris (BF), and semitendinosus (ST). The muscles were chosen for their attachments to the thoracolumbar fascia and their potential to act on the trunk, pelvis, and hips. Seventeen healthy male subjects participated in the study. Each subject did three squat lifts with a 157-N crate, with the spine in both a lordotic and kyphotic posture. The lift was divided into four equal periods. EMG activity of each muscle was quantified for each period and normalized to the peak amplitude of a maximal voluntary isometric contraction (MVIC). A two-way analysis of variance (ANOVA) for repeated measures was used to analyze the effects of posture on the amplitude and timing of EMG activity during the lift. Two patterns of EMG activity were seen: a trunk muscle pattern (RA, AO, ES, and LD) and a hip extensor pattern (GM, BF, ST). In the trunk muscle pattern (TP), EMG activity was greatest in the first quarter and decreased as the lift progressed. In the hip extensor pattern (HP), EMG activity was least in the first quarter, increased in the second and third quarters, and decreased in the final phase of the lift. Differences (P < .05) were seen among subjects and in the timing of the muscle activity in all muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Sulphatide in islets of Langerhans and in organs affected in diabetic late complications: a study in human and animal tissue.

Sulphatide has been found in rat islets of Langerhans and anti-sulphatide antibodies have been demonstrated in patients with insulin-dependent diabetes mellitus. Using a specific monoclonal antibody, Sulph I, directed against sulphatide, we investigated the in situ distribution of this glycolipid immunohistochemically; furthermore, the sulphatide concentration was determined in several organs and cells by thin-layer chromatography. The islets of Langerhans in all species examined, mouse, rat, pig, and monkey were intensively stained but exocrine tissue remained unlabelled. The sulphatide concentration in human islets was 150 +/- 46 pmol/100 islets. The only glycolipid-antigen detected was sulphatide. Regarding other tissues, sulphatide was found to be located in distal tubules in the kidney, peripheral nerves, distinct scattered spot-like structures in the choreoid layer of the eye, the ovum, and peripheral granulocytes. Sulph I injection in mice showed homing to kidney tubules, Lung, heart, liver, adrenal, spleen, lymph node and thymus were not stained by Sulph I. Thus, the distribution of sulphatide shows an association with organs known to be affected in diabetes, either initially or in late complications.

Adult↗
PubMed1994

Antipsoriatic effect of fumaric acid derivatives. Results of a multicenter double-blind study in 100 patients.

BACKGROUND: Psoriasis vulgaris may benefit from treatment with fumaric acid and/or its derivatives; however, because different preparations have been used, results have been contradictory and difficult to interpret. OBJECTIVE: The purpose of this clinical trial was to evaluate the therapeutic value of fumaric acid derivatives. METHODS: A randomized double-blind study was carried out in patients with psoriasis, comparing a well-characterized formulation of fumaric acid derivatives with placebo. RESULTS: The results indicated statistically significant superiority of the fumaric acid derivatives over placebo. Adverse events (flush, gastrointestinal disturbances) were initially relatively frequent, but decreased thereafter. CONCLUSION: Fumaric acid derivatives were found to be effective and safe in the treatment of psoriasis.

Abdominal Pain↗
PubMed1994

Urine profiles and kidney histology after intravenous injection of ionic and nonionic radiologic and magnetic resonance contrast media in normal rats.

RATIONALE AND OBJECTIVES: Previous studies showed that both high-osmolality and low-osmolality iodinated contrast media cause temporary albuminuria and enzymuria (presence of enzymes in urine) in normal rats. Whether the same is true with ionic high-osmolality and nonionic low-osmolality magnetic resonance (MR) contrast media is unknown. We studied urine profiles and histology after intravenous injection of four types of contrast media in rats with normal kidneys. METHODS: Urine profiles were monitored 4, 24, 48, and 72 hr after intravenous injection of saline, diatrizoate, iohexol, gadopentetate dimeglumine, and gadodiamide (4.59 mmol/kg of body weight) in normal rats. Each group included 20 male rats. After sacrifice, both kidneys were removed for examination by light microscopy (LM) and electron microscopy (EM). RESULTS: All four contrast agents caused a temporary (< 22 hr) increase in the excretion of albumin (2-5 times) and of cytoplasmic (30-100 times) and brush border (10-100 times) renal enzymes when compared with saline. The degree of albuminuria correlated well (r = 0.90) with the osmolality of the injected media, whereas the increased level of enzymuria was unrelated to the osmolality. No major differences in the enzymuric effects of the four agents were noted. LM revealed vacuoles in all kidneys exposed to radiologic contrast media but not in kidneys exposed to MR contrast media or saline. Slight vacuolation was revealed by EM after the use of MR contrast media, and significant vacuolation was evident via EM after the use of radiologic contrast media. No difference between ionic and nonionic media within each drug group was detected by either LM or EM. CONCLUSIONS: Transient renal effects are induced by both ionic and nonionic high-osmolality and low-osmolality radiologic and MR contrast media in normal rats. Both osmotic (e.g., albuminuria) and chemotoxic (e.g., enzymuria) mechanisms seem to be involved. From a morphologic point of view, the chemotoxic mechanisms seem to be of major importance.

Animals↗
PubMed1994

Histiocytic sarcomas and monoblastic leukemias. A clinical, histologic, and immunophenotypical study.

Eight histiocytic sarcomas, identified by examination of more than 2000 malignant lymphomas, are described. For comparison, tumor infiltrates from five monoblastic leukemias were also analyzed. The histiocytic sarcomas were all high-grade malignancies consisting of markedly pleomorphic large cells with many mitotic figures. At presentation, six of the patients had systemic symptoms (fever, fatigue, loss of weight), skin infiltrates, and lymphadenopathy. Despite aggressive chemotherapy, clinical remissions were short, and six patients died of disease .5-48 months (mean, 6.5 months) after diagnosis. The remaining two patients are alive and in partial or complete remission 7 and 12 months after diagnosis. Immunotypic examination showed that all the histiocytic sarcomas were positive for macrophage-related antigens and negative for antigens on B cells, T cells, myeloid cells, epithelial cells, and melanocytes. T-cell receptor and immunoglobulin genes were studied in three cases and were present in a germline configuration. One of the histiocytic sarcomas resembled Langerhans' cells in phenotype and morphology; it was classified as a Langerhans' cell sarcoma. The remaining histiocytic sarcomas did not express accessory cell-associated antigens, but more closely resembled "ordinary" tissue macrophages; they were positive for lysozyme and/or CD68, followed in frequency by CD11c, CD4, CD11b, CDw32, peanut agglutinin receptor, and CD13. Similar features were seen in the monoblastic leukemias. These conditions could only be distinguished from histiocytic sarcoma by clinical and morphologic, rather than immunophenotypic, criteria. Expression of oncoprotein p53 was studied in nine cases and was positive in six of six histiocytic sarcomas and one of three monoblastic leukemias. Rare malignancies show features consistent with the derivation from macrophages. Two entities may be distinguished: those that resemble antigen-presenting accessory cells and those that more closely resemble ordinary tissue macrophages. Recognition of these tumors is important clinically and requires assessment of clinical, morphologic, and immunophenotypic features, supplemented by analysis of T-cell receptor and immunoglobulin genes. Whether (or how) p53 gene mutations are implicated in their pathogenesis will be an important topic for future investigation.

Adolescent↗
PubMed1994

Osmotic stimulation of the supraoptic nucleus: central and peripheral vasopressin release and blood pressure.

Experiments were performed to determine the effect of direct osmotic stimulation of the supraoptic nucleus (SON) on central and peripheral vasopressin (AVP) release and arterial pressure. A microdialysis method was used to deliver hyperosmotic NaCl, mannitol or urea bilaterally into the SON and to sample SON extracellular fluid and blood. Simultaneous brain and blood microdialysis showed that hyperosmotic NaCl increased central and peripheral AVP release and increased mean arterial pressure (MAP). The pressor response was not blocked by intravenous injection of a V1-receptor antagonist, D(CH2)5Tyr(Me)AVP, suggesting that circulating AVP was not involved in that response. Hyperosmotic mannitol or urea caused an increase in central peptide release, but failed to affect MAP or peripheral AVP release. The results suggest that central AVP release within the SON may be due to osmoreceptor stimulation while the peripheral effects on AVP release and MAP are specific for sodium. The results also demonstrate the utility of brain and blood microdialysis for the delivery of stimuli into specific brain regions with simultaneous monitoring of central and peripheral peptide release.

Animals↗
PubMed1994

Nitric oxide actions in paraventricular nucleus: cardiovascular and neurochemical implications.

We have examined potential functions of nitric oxide (NO) within the paraventricular nucleus (PVN) in urethan-anesthetized male Sprague-Dawley rats. Initial experiments demonstrated microinjection of 50 pmol of the NO donor, sodium nitroprusside (SNP), directly into the PVN resulted in significant decreases in mean blood pressure (BP) (-3,312 +/- 1,189 mmHg/s over 300-s response time; P < 0.05). To determine whether such effects were attributable to SNP-induced NO release, NO was administered into PVN directly by bilateral microdialysis of NO-containing artificial cerebrospinal fluid (NO-aCSF), a process that results in delivery of approximately 50 pmol NO.PVN-1 x min-1. Such microdialysis resulted in significant decreases in BP (-5,121 +/- 817 mmHg/s over 1,200-s response time; P < 0.005), while aCSF microdialysis was without effect (1,298 +/- 1,071 mmHg/s over 1,200-s response time; P > 0.1). Amino acid concentrations were measured in dialysates collected during perfusion of the same PVN sites with either aCSF or NO-aCSF by high-performance liquid chromatography (HPLC) analysis. NO-aCSF induced significant increases in aspartate (aCSF 31 +/- 7 pmol/30 min; NO-aCSF 134 +/- 33 pmol/30 min; P < 0.05), glutamate (aCSF 36 +/- 5 pmol/30 min; NO-aCSF 417 +/- 108 pmol/30 min; P < 0.02), gamma-aminobutyric acid (aCSF 4.1 +/- 0.7 pmol/30 min; NO-aCSF 104 +/- 29 pmol/30 min; P < 0.02), and taurine (aCSF 34 +/- 3 pmol/30 min; NO-aCSF 117 +/- 24 pmol/30 min; P < 0.01) concentrations, while alanine, glutamine, and serine concentrations were unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1994

Reduced febrile responses to pyrogens after lesions of the hypothalamic paraventricular nucleus.

The hypothalamic paraventricular nucleus (PVN) is recognized as a major site of autonomic control, but the role of this nucleus in thermoregulation is unclear. Therefore the role of the PVN in the febrile response and in the maintenance of normal body temperature was investigated. Conscious, unrestrained rats with chronic lesions of the PVN received intracerebroventricular injections of several doses of prostaglandin (PG) E2 or intraperitoneal applications of Escherichia coli lipopolysaccharide. The body temperatures of both lesioned and sham-operated animals, monitored via radio telemetry, were compared. Intracerebroventricular PGE2 at doses of 10, 25, and 50 ng caused dose-dependent fevers in both PVN-lesioned and sham-operated animals, which at lower doses were smaller in the lesioned animals than in the sham-operated animals. Intraperitoneal lipopolysaccharide application, 50 micrograms/kg body wt, evoked a significantly lower febrile response in PVN-lesioned animals than in controls. The body temperature of PVN-lesioned animals and controls showed no difference during 300 min of exposure to heat (32 degrees C) or cold (7 degrees C). These results suggest that the PVN contributes to the complex regulation of temperature during the febrile response but not during the maintenance of normal body temperature.

Animals↗
PubMed1994

Isolation and culture of human endometrial cells in a three-dimensional culture system.

A cell culture system was established in which endometrial stromal cells were embedded in a collagen matrix and separated from the endometrial epithelium by basement membrane material (Matrigel). The epithelium, seeded on top of the collagen matrix, grew in a monolayer. The cultures were evaluated by light microscopy and transmission and scanning electron microscopy. Light and transmission electron microscopy indicated a polarized columnar epithelium in monolayer with basally positioned nuclei. Scanning electron microscopy revealed a confluent epithelium with an abundance of microvilli and cilia, as well as pinopodes on the apical surface. Immunohistochemical staining for cytokeratin confirmed the epithelial origin of the surface cells, and staining for human collagen IV demonstrated its presence underneath the epithelial cells. This culture system represents a three-dimensional system that imitates the normal endometrium.

Biocompatible Materials↗
PubMed1994

Transverse folds of the adult obstructed ureter. Case report.

Transverse folds in the distal ureter were found on urograms in two adult patients with ureteral obstruction. These folds were associated with but did not cause ureteral obstruction. Histopathological examination of the excised ureter in one patient showed that the folds were made of luminal projections of lamina propria containing prominent bundles of smooth muscle. The folds probably originate as a result of a lower compliance of the distal part of the ureter, which reduces the distension produced by a luminal rise in pressure.

Adult↗
PubMed1993

Microsatellite instability in bladder cancer.

Somatic instability at microsatellite repeats was detected in 6 of 200 transitional cell carcinomas of the bladder. Instabilities were apparent as changes in (GT)n repeat lengths on human chromosome 9 for four tumors and as alterations in a (CAG)n repeat in the androgen receptor gene on the X chromosome for three tumors. Single locus alterations were detected in three tumors, while three other tumors revealed changes in two or more loci. In one tumor we found microsatellite instability in all five loci analyzed on chromosome 9. The alterations detected were either minor 2-base pair changes or larger (> 2 base pairs) alterations in repeat length. All six tumors were low stage (Ta-T1), suggesting that these alterations can occur early in bladder tumorigenesis.

Base Sequence↗
PubMed1993

Diagnostic value of cerebrospinal fluid cytology in comparison with tumor marker activity in central nervous system metastases secondary to breast cancer.

BACKGROUND: Central nervous system (CNS) metastases occur in approximately 35% of patients with breast cancer. Parenchymal brain metastases (MET) remain undetected in a large proportion of patients, and only 50% of patients with leptomeningeal carcinomatosis (MC) are diagnosed in vivo. METHODS: Cytology and activity of the tumor markers tissue polypeptide antigen (TPA) and creatine kinase-BB isoenzyme (CK-BB) were evaluated in the cerebrospinal fluid (CSF) in 71 consecutive patients with breast cancer suspected for CNS metastases. RESULTS: Forty-three patients had no CNS metastases, 12 patients had MET, 5 patients had both MET and MC, and 11 patients had MC alone. Seven of the patients with MC had an intracerebroventricular (ICV) reservoir inserted, and an additional 70 ICV CSF samples from these patients were obtained. In CSF obtained by lumbar puncture, 11% of the samples were classified as "suspicious for malignancy," but a very limited interobserver variability was demonstrated (Kappa test value, 0.81; 95% confidence limits, 0.67-0.95%). Fifty-one percent of the ICV CSF samples were classified as "suspicious for malignancy" (Kappa test value, 0.58; 95% confidence limits, 0.34-0.82%). TPA and CK-BB were both measured in 101 CSF specimens (61 from lumbar puncture and 40 ICV samples). The differences between patients with and without CNS metastases were significantly different according to TPA (P < 0.00001) and CK-BB (P < 0.00003; Mann-Whitney test). The sensitivity and predictive value of a negative test for having any CNS metastases (in case of elevated values of either TPA or CK-BB or both) were 85% (95% confidence limits, 65-96%) and 90% (95% confidence limits, 76-97%), respectively. In addition, a significant correlation between TPA and CK-BB was demonstrated in CSF from lumbar puncture (Spearmans-Rho, 0.49; P < 0.0001) and ICV (Spearmans-Rho, 0.37; P < 0.02). CONCLUSIONS: Cytologic evaluation of CSF obtained by lumbar punctures is a reliable procedure. In CSF from ICV reservoirs, cytologic evaluation is of limited use, but CK-BB and TPA is of potential value.

Antigens, Neoplasm↗
PubMed1993

Sulphatide and sulphatide antibodies in insulin-dependent diabetes mellitus.

Insulin-dependent diabetes mellitus (IDDM) is associated with neurological disorders. Sulph I, a monoclonal antibody to sulphatide (a neural epitope), stained secretory granules in alpha and beta cells of rat islets of Langerhans, but not exocrine tissue. Sera from 88% of 57 newly diagnosed IDDM patients was anti-sulphatide positive, and 76% were positive 6 months later. All 135 healthy controls were negative. Sulphatide antibody may be an IDDM marker.

Adult↗
PubMed1993

[Electron microscopy of needle biopsies from cancer patients with unknown primary tumors].

The aim of the present study was to evaluate the diagnostic value of electron microscopy (EM) performed on Surecut biopsies from patients without known primary tumour. The material consisted of 108 consecutive biopsies, obtained over a period of two years, from patients with tumour(s) in the liver or lymph nodes (on the neck, in the axilla or retroperitoneum). From each patient fine needle aspirations and Surecut biopsies for light microscopy and electron microscopy were taken. Only biopsies in which material for both electron microscopy and light microscopy was sufficient were included (60%). Immunohistochemical reactions were performed on paraffin sections when indicated. Final diagnoses were confirmed on surgically removed specimens and/or autopsies. Electron microscopy was necessary for obtaining the final histological diagnosis in 15% of the cases. It is therefore recommended to obtain additional ultrasound guided biopsies for EM from cancer patients with tumours in the liver or lymph nodes in cases where the primary origin of the tumour is unknown.

Biopsy, Needle↗