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Biomedical subjects

A Hess

Publications and source records attributed to A Hess.

At least 55 records · Page 3Linked to original sources
PubMed1998

Localisation of the nitric oxide (NO)/cGMP-pathway in the vestibular system of guinea pigs.

The exact distribution of nitric oxide-synthases (NOS) in the vestibular system has not been described satisfying yet. Immunostaining, using specific antibodies to the three known NOS-isoforms, to cyclic guanosine monophosphate (cGMP) and soluble guanylyl-cyclase (sGC), the second messenger system of nitric oxide (NO), was performed on paraffin sections of temporal bone from guinea pigs. eNOS could be detected in vestibular ganglion cells and in nerve fibres, including the calyces, surrounding the type 1 hair cells (HC). bNOS was found in the sensory epithelium, ganglion cells and in bone, while iNOS could not be found. NOS-detection was accompanied by reactivity to sGC and to cGMP. This finding implies that b- and eNOS-generated NO is involved in regulative processes in neurotransmission and regulation of blood flow.

Animals↗
PubMed1998

In vitro expression of inducible nitric oxide synthase in the nasal mucosa of guinea pigs after incubation with lipopolysaccharides or cytokines.

In order to demonstrate the involvement of nitric oxide synthases (NOS)--in particular the inducible isoform (iNOS)--in inflammatory processes within the nasal airways, we used organ-bath incubation to study isolated inferior turbinates and mucosa of the maxillary sinus of guinea pigs. The pattern of the expression in various substructures of the nasal mucosa was of special interest. Mucosa was incubated for 6 h with lipopolysaccharides (LPS) produced by E. coli, interleukin II (IL-2) or tumor necrosis factor-alpha (TNF-alpha). Saline was used as the control solution. Following incubation the specimens were fixed in buffered 4% formaldehyde solution over a period of 4 h. Tissues were next exposed to nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase-reaction and immunostained with specific antibodies to iNOS. Results then showed a clearly increased or initiated expression of iNOS in epithelium, glands, leucocytes and blood vessels of treated tissues in comparison to the control specimens. The inflammatory mediator LPS and the cytokines Il-2 or TNF-alpha alone were found to be capable of increasing the expression of iNOS, although the effects of LPS clearly exceeded those of the cytokines. This finding implicates iNOS-generated nitric oxide as a key factor for causing nasal swelling, secretion and obstruction during nasal infections and allergic episodes.

Animals↗
PubMed1998

[Rhabdomyosarcoma in the area of the head-neck. A synopsis of some cases, therapeutic possibilities and prognoses].

BACKGROUND: Soft tissue sarcoma represent approximately 7% of all neoplasms in children up to 14 years. The most common type (approx. 50%) among them is the rhabdomyosarcoma (RMS). Within the head and neck, which accounts for approx. 35% of all RMS, the tumor can be found ubiquitiously. Preferred localizations are the orbita, the paranasal sinuses, and the soft tissue of cheek and neck. The prognosis of RMS was formerly poor but has markedly improved since defined multimodal therapy was established in the Seventies (for example the Intergroup Rhabdomyosarcoma Study, IRS, in 1972; the International Society of Paediatric Oncology, SIOP, in 1975, or the German "Cooperative Weichteil-Sarkom-Studien", CWS, in 1981). The therapy of choice for RMS, according to the CWS, is chemotherapy because very often a good remission of the tumor is achieved. The main role of surgery is first to obtain biopsy specimens for histological diagnosis, and second aim is the complete resection of the primary and resectable metastases, for example by a neck dissection. Severe mutilation by radical surgery, especially in childhood, should be avoided in favor of multidrug chemotherapy and radiation in the interest of patient well-being. PATIENTS: Our retrospective study shows the treatment and results of 11 patients with a rhabdomyosarcoma of the head and neck within 25 years (1972-1997). RESULTS: Five of the 11 patients, who were treated in the years 1972-77, died (average 13 months, range 3-72 months). Five of the six patients, who were treated since 1991, have survived to date, one had a relapse of the tumor. Four special cases of patients are discussed in greater detail. CONCLUSION: Although the achieved mean survival time is encouraging nowadays (a 5-year survival rate of approx. 70% for all RMS is described) fatal cases are typical for this malignancy. Early diagnosis, localization, histological subtype, and prompt initiation of adequate treatment is decisive for a successful outcome.

Adolescent↗
PubMed1997

In situ analysis of denitrifying toluene- and m-xylene-degrading bacteria in a diesel fuel-contaminated laboratory aquifer column.

A diesel fuel-contaminated aquifer was bioremediated in situ by the injection of oxidants (O2 and NO3-) and nutrients in order to stimulate microbial activity. After 3.5 years of remediation, an aquifer sample was excavated and the material was used (i) to isolate bacterial strains able to grow on selected hydrocarbons under denitrifying conditions and (ii) to construct a laboratory aquifer column in order to simulate the aerobic and denitrifying remediation processes. Five bacterial strains isolated from the aquifer sample were able to grow on toluene (strains T2 to T4, T6, and T10), and nine bacterial strains grew on toluene and m-xylene (strains M3 to M7 and M9 to M12). Strains T2 to T4, T6, and T10 were cocci, and strains M3 to M7 and M9 to M12 were rods. The morphological and physiological differences were also reflected in small sequence variabilities in domain III of the 23S rRNA and in the 16S rRNA. Comparative sequence analyses of the 16S rRNA of one isolate (T3 and M3) of each group revealed a close phylogenetic relationship for both groups of isolates to organisms of the genus Azoarcus. Two 16S rRNA-targeted oligonucleotide probes (Azo644 and Azo1251) targeting the experimental isolates, bacteria of the Azoarcus tolulyticus group, and Azoarcus evansii were used to investigate the significance of hydrocarbon-degrading Azoarcus spp. in the laboratory aquifer column. The number of bacteria in the column determined after DAPI (4',6-diamidino-2-phenylindole) staining was 5.8 x 10(8) to 1.1 x 10(9) cells g of aquifer material-1. About 1% (in the anaerobic zone of the column) to 2% (in the aerobic zone of the column) of these bacteria were detectable by using a combination of probes Azo644 and Azo1251, demonstrating that hydrocarbon-degrading Azoarcus spp. are significant members of the indigenous microbiota. More than 90% of the total number of bacteria were detectable by using probes targeting higher phylogenetic groups. Approximately 80% of these bacteria belonged to the beta subdivision of the class Proteobacteria (beta-Proteobacteria), and 10 to 16% belonged to the gamma-Proteobacteria. Bacteria of the alpha-Proteobacteria were present in high numbers (10%) only in the aerobic zone of the column.

Bacteria↗
PubMed1996

CTLA4Ig inhibits alloantibody responses to repeated blood transfusions.

Allosensitization is a fundamental problem that limits the effectiveness of blood transfusions. Patients who receive multiple transfusions of blood or blood components frequently develop alloantibodies against donor alloantigens. Allosensitized patients are refractory to further transfusion and difficult to transplant successfully. CTLA4Ig fusion protein, which blocks the CD28-B7 costimulatory pathway in T-lymphocyte activation, was tested for its capacity to inhibit allosensitization to blood transfusions. Groups of LEW (RT1') rats were transfused with ACI blood (RT1a) together with L6 (a human immunoglobulin G1 [IgG1] antibody as isotype control) or CTLA4Ig in different doses (0.004, 0.02, 0.1, and 0.5 mg). Rats were retransfused with ACI blood after 28 and 84 days without any additional CTLA4Ig therapy. Weekly sera samples were tested for alloantibody against donor leukocytes using flow cytometry. CTLA4Ig caused a dose-dependent decrease in the IgM alloantibody response against donor major histocompatibility complex (MHC) class I antigens. In addition, 0.02-, 0.1-, and 0.50-mg doses of CTLA4Ig totally inhibited the IgG responses to the first transfusion, and this immunosuppressive effect persisted for the second and third transfusions. To study the capacity of CTLA4Ig to prevent a secondary immune response, three groups of LEW rats were transfused with ACI blood with no accompanying treatment. Animals were retransfused 28 days later with ACI blood together with L6 control antibody or 0.5 or 2.5 mg CTLA4Ig. CTLA4Ig, but not L6, prevented an increase in IgG alloantibody response despite repeated transfusions. The effects of CTLA4Ig treatment on helper T-lymphocyte proliferation was tested by limiting dilution analysis (LDA). Peripheral blood cells taken 30 days after blood transfusion and CTLA4Ig treatment contained significantly decreased donor-specific T-lymphocyte precursors compared with L6-treated rats. These data support the idea that blocking the B7/CD28 signal of T-lymphocyte activation by CTLA4Ig treatment at the time of transfusion may be an important therapeutic tool to inhibit alloantibody responses to blood transfusions.

Abatacept↗
PubMed1996

Optical and FDG mapping of frequency-specific activity in auditory cortex.

With optical recording of intrinsic signals (ORIS) and tone stimulation, we analysed frequency- and intensity-dependent spatio-temporal activity in primary auditory cortex AE of awake Mongolian gerbils. We found a two-dimensional and assymetric propagation of ORIS activity (1) from ventral to dorsal along isofrequency contours at all frequencies and (2) from the low-frequency end across the complete tonotopic gradient at low frequencies. High-frequency representations remained tonotopic. Tonotopic asymmetries were independent of stimulus intensity. By contrast, in fluoro-2-deoxyglucose images from the same animals metabolic activity was tonotopically confined at high and low frequencies. The assymetric tonotopic propagation of ORIS activity suggests subthreshold directional interaction mechanisms in the cortical network which may serve to relate low- to high-frequency components of complex sounds.

Acoustic Stimulation↗
PubMed1995

Syngeneic bone marrow transplantation eliminates V beta 8.2 T lymphocytes from the spinal cord of Lewis rats with experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE), an animal model for multiple sclerosis (MS), is a paralytic disease of the central nervous system (CNS) mediated by T-lymphocytes reactive to myelin basic protein (MBP). Lewis rats actively immunized with fragment 68 to 82 of guinea pig MBP develop a monophasic disease with spontaneous recovery. Lymphocyte recognition of the primary encephalitogenic sequence of MBP (fragment 68 to 82) is V beta 8.2 T cell receptor (TCR) skewed [1-3]. Lewis rats in clinical remission at 1 month and 3 months after spontaneous resolution of EAE retain V beta 8.2 T-lymphocytes in the CNS when analyzed by reverse transcriptase polymerase chain reaction or in situ hybridization. In contrast, 1 and 3 months after clinical remission from syngeneic bone marrow transplantation, V beta 8.2 T lymphocytes are absent from the CNS. During clinically active EAE and inflammatory breakdown of the blood-brain barrier, immune ablation and reconstitution with syngeneic bone marrow results in clinical tolerance of the new immune system to myelin.

Animals↗
PubMed1995

Bone marrow transplantation for multiple sclerosis.

Multiple sclerosis is the most common demyelinating neurologic disease. Animal studies from three separate institutions suggest that BMT may be beneficial. Of paramount concern is the risk to benefit ratio. However, for patients with progressive disease at onset, survival is similar to patients with indolent lymphomas; while for patients with malignant MS, survival is roughly equivalent to chronic phase CML. In addition, for these patients, life may become intolerable due to progressive pain and disability. The fate of such individuals may justify, in carefully selected patients and in a controlled investigational protocol, the risk of early mortality from BMT.

Animals↗
PubMed1994

[Radiation-exposure studies of CT diagnosis with the standard and spiral technics].

Comparison of the radiation exposure during CT quoted in the literature shows considerable variation; this depends on differences in apparatus, methods of examination and measurements. A systematic investigation into radiation dose during CT is therefore necessary to obtain accurate radiation doses during various examinations in order to balance risks against usefulness. The present paper deals with the radiation dose received by the patient during examinations of the cerebrum, neck, thorax, upper and lower abdomen and pelvis, using standard and spiral CT techniques. Organ doses for all organs at risk, surface dose, total body dose and dose profiles along the body axis for each type of examination have been established, which will allow the user to evaluate radiation dose.

Female↗
PubMed1993

[The physical and technical outlook for neutron therapy in Germany].

All five fast neutron therapy centres in Germany use low energy cyclotrons or neutron generators and are, therefore, at the low energy end of the 21 neutron therapy facilities presently in use worldwide. The depth dose characteristics are worse than for 60Co gamma rays, the absorbed dose rate is too low and the treatment is technically restricted because of the lack of those modern features like multileaf collimators and full gantry rotation that are available with modern linear accelerators. A survey of the statistical and methodical data on the neutron treatment in Germany is presented. To avoid masking the potential biological benefits of high LET neutron irradiation by the use of suboptimal equipment and to utilise the real therapeutical benefit for specific tumor types, the German neutron therapy centres urgently need modernization of their outdated facilities. Specific recommendations of how to meet the requirements of modern neutron therapy are given.

Fast Neutrons↗
PubMed1991

Assigning priority to patients requiring coronary revascularization: consensus principles from a panel of cardiologists and cardiac surgeons.

In light of lengthy waiting lists for coronary surgery in Canada, a panel of 16 cardiologists and cardiac surgeons was convened to derive guiding principles for ranking how urgently diverse patients with angiographically proven coronary disease require revascularization. Factors likely to affect urgency were agreed upon by the panelists and incorporated into a case scenario questionnaire. Each panelist then rated 438 case scenarios with respect to maximum acceptable waiting time on a scale with seven time frames ranging from emergency surgery ('level 1') to delays of up to six months ('level 7'). The scenario rating process facilitated attainment of a panel consensus. The purpose of the principles is to assist in assigning priorities to patients according to both symptoms and risk of death or additional morbidity from ischemic events. The pattern or severity of the patient's anginal symptoms and the response of those symptoms to medical therapy emerged as the single most important determinant of the level of urgency. Anatomy and noninvasive tests of ischemic risk were the other key determinants of priority. All other factors were less important, and operated largely within a given level of urgency on the seven-point scale. The principles, including explicit ranking criteria divided according to angina class, are outlined in this final report. The panel specifically cautioned that adoption of such principles is not designed to countenance delays in treatment, but if necessary, should help form more rational queues for coronary revascularization.

Canada↗
PubMed1990

The effects of monoamine oxidase inhibition and dopamine uptake blockade on MPTP-induced increase of 2-[3H]deoxyglucose uptake in specific mesencephalic catecholaminergic nuclei.

Intraperitoneal injection in C57 black mice of 30 or 7.5 mg/kg MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) followed 1-2 h later by 0.5 mCi/100 g 2-[3H]deoxyglucose (2-DG) produces an intense increase of 2-DG uptake in the dopaminergic zona compacta (ZC) of the substantia nigra and the adjacent ventral tegmental area (VTA) as seen in autoradiographs. Anesthetized animals also exhibit this reaction. Clorgyline (10 mg/kg), a monoamine oxidase (MAO)-A inhibitor, 30 min before MPTP does not block this reaction. Deprenyl (10 mg/kg), an MAO-B inhibitor, blocks increased 2-DG uptake in ZC and VTA if injected 30 min or 12 h before 7.5 mg/kg MPTP, but has no effect if injected 12 h before 30 mg/kg MPTP. Mazindol (10 mg/kg), a dopamine uptake blocker, is effective in blocking the action of 7.5 mg/kg MPTP, but ineffective against 30 mg/kg MPTP. Heavier doses of MPTP can, in some instances, overcome the actions of MAO inhibitors or dopamine uptake blockers in preventing the increased 2-DG uptake elicited by MPTP. But, essentially, the intensely increased glucose metabolism acutely induced in specific catecholaminergic neurons appears to be another significant pathological feature of the dopaminergic neurotoxicity caused by MPTP which can be prevented by MAO inhibition or dopamine uptake blockade.

Animals↗
PubMed1990

Human chromogranin A-like immunoreactivity in the Bergmann glia of the rat brain.

A mouse monoclonal antibody to human chromogranin A (LK2H10) selectively stains the Bergmann glia (Golgi epithelial cells) of the rat cerebellum, while rabbit antibodies to bovine or porcine chromogranin A do not. Chromogranin A immunostaining in the cell bodies and processes reveals the characteristic candelabra morphology seen in Golgi preparations of these cells. Immunostaining adjacent sections with antibodies to glial fibrillary acidic protein shows that a relatively small number of the glial cell processes in the molecular layer are chromogranin A positive. Recent reports indicate that the metabolites of chromogranin A play a regulatory role in endocrine and neuroendocrine systems but the function of chromogranins in neurons and glia is unknown.

Animals↗
PubMed1990

Acute neuropathological changes in the caudate nucleus caused by MPTP and methamphetamine: immunohistochemical studies.

Three days after the administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) or methamphetamine to mice, there is degeneration and disappearance of punctate tyrosine hydroxylase-containing synaptic endings in the caudate nucleus. The neuropil is occupied with longer, varicose, branching fibres, which appear to be preterminal fibres. An intense gliosis occurs. The sparsely-occurring glial cells, with profuse lightly-stained (by glial fibrillary acidic protein) processes which are primarily located near blood vessels, become transformed into more heavily-stained star-shaped cells with fewer but thicker processes. These cells are distributed throughout the caudate. Despite apparent differences in the mechanism by which MPTP and methamphetamine cause dopamine depletion, the neuropathological changes in the caudate induced by these substances are identical.

Animals↗
PubMed1990

[Suction cup ocular pressure versus Vörösmarthy oculopression. Biometry differences].

In a 20-min follow-up after oculopression, biometric measurements were taken before, immediately after, and 5, 10, 15 and 20 min after finishing oculopression. Thirty-two eyes were measured by ultrasound using the immersion technique with a 10 MHz A-scan probe. Sixteen cataract patients more than 50 years of age and 16 healthy young subjects up to 30 years of age took part in the study. Oculopression was performed either with a Honan Oculopressor or with a Mikuni and Yoneyama suction-cup oculodynamometer. The anterior chamber depth showed higher initial deepening following Honan oculopression, whereas the length of the vitreous was found to be shorter with the same method. Suction-cup oculopression revealed no distinct changes in these compartments. Nevertheless, 10 min after oculopression, there was no statistically significant difference between the two oculopression techniques. When comparing the age groups, the cataract patients showed more express change than the younger subjects.

Adult↗
PubMed1990

[Secondary malignomas following radiotherapy of breast carcinoma: a case report].

Numerous cases of radiation-induced malignoma have been described, where the radiation osteosarcomas are placed in the foreground. In this article a case of a female patient is described who developed not only a radiation-induced osteosarcoma but also a thyroid gland carcinoma after a previous postsurgical mamma carcinoma whereby the irradiation dose of the radiation sarcoma is about 64 Gy and for the thyroid gland carcinoma about 12 Gy.

Adenoma↗