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Biomedical subjects

M Hess

Publications and source records attributed to M Hess.

At least 55 records · Page 3Linked to original sources
PubMed2002

[Possibility for endolaryngeal morphometric measurements with a new laser light method].

Morphometric measurement of horizontal laryngeal structures is difficult and poses many problems in laryngology. It is difficult to determine the size of vocal fold tissue lesions as well as the range of amplitudes during vocal fold vibration in rigid endoscopy. We present a new method by using two parallel light beams which are projected onto the surface of the vocal folds during examination of the larynx with a rigid 90 degrees-endoscope. Because of the fixed distance of the light points, measurement of the laryngeal structures can be accomplished, e.g., using a video print after the examination. With this new technique morphometric measurement of horizontal laryngeal structures during routine endoscopic examination becomes feasible.

Equipment Design↗
PubMed2002

[Physical and technical elements of short-interval, color-filtered double strobe flash-stroboscopy].

INTRODUCTION: Quantitative measurement of vocal fold movements can be done either with high-speed imaging or with short interval, color-filtered double strobe flash-stroboscopy. The physical and technical elements of this new technique are described. METHODS: Two special strobe units (KAY Elemetrics RLS 9100) are used in a master-slave configuration. In this way an adjustable interval of 0.1-2.0 ms between flashes is introduced. The strobe flashes are color filtered and are separated by a brief interval. By this means a double exposure is created in each video frame.Real-time visualization of opening and closing velocities over the entire length of the vocal fold from anterior to posterior is possible. Quantification is possible off-line after image calibration. CONCLUSION: Short-interval, color-filtered double-strobe flash stroboscopy allows quantitative measurement of the velocity of vocal fold movements during vibration at different pitches and sound pressure levels (SPL). Images gained with this new technique provide information about a dynamic property (velocity) of the vocal fold within a single image.Therefore, its use could be helpful from the aspect of clinical documentation.

Artifacts↗
PubMed2002

The use of PCR combined with restriction enzyme analysis to characterize fowl adenovirus field isolates from northern India.

Ten fowl adenoviruses (FAVs), isolated from suspected cases of inclusion body hepatitis (IBH) in quails and broilers, were characterized by a hexon-based polymerase chain reaction (PCR) combined with restriction enzyme analysis (REA) of the amplified DNA fragments. All the isolates could be detected using H1/H2 and H3/H4 primer sets. Amplification of DNA with H1/H2 and H3/H4 primer sets resulted in fragments of approximately 1219 bp and 1319 bp, respectively. HaeII digestion of the H1/ H2 PCR products and HpaII digestion of the H3/H4 PCR products characterized all the isolates in FAV groups, known from genomic typing using the whole DNA. For some of the isolates, neutralization tests were used to confirm these results. The results revealed that, as well as FAV serotype 1, which is the sole member of DNA group A, FAVs of DNA group E are also associated with IBH in poultry in northern India. The FAV specific PCR combined with REA was found to be very useful in investigating the epidemiological situation in the field. It was even possible to define mixed infections with more than one FAV.

Adenoviridae Infections↗
PubMed2002

Inhibition of human natural killer cell activity by cereulide, an emetic toxin from Bacillus cereus.

The lipophilic toxin, cereulide, emitted by emetic food poisoning causing strains of Bacillus cereus, is a powerful mitochondria toxin. It is highly lipophilic and rapidly absorbed from the gut into the bloodstream. We tested how this toxin influences natural killer (NK) cells, which are important effectors in defence against infections and malignancy. Cereulide inhibited cytotoxicity and cytokine production of natural killer cells, caused swelling of natural killer cell mitochondria, and eventually induced natural killer cell apoptosis. The suppressive effect on cytotoxicity was fast and toxic concentration low, 20-30 microg/l. As the emesis causing concentration of cereulide is around 10 microg/kg of total body mass, our results suggest that emesis causing or even lower doses of cereulide may also have a systemic natural killer cell suppressive effect.

Apoptosis↗
PubMed2002

A fiber gene-based polymerase chain reaction for specific detection of pigeon adenovirus.

A polymerase chain reaction (PCR) was developed to detect a recently described pigeon adenovirus (PiAV). Primers located in the fiber gene of PiAV amplified a PCR fragment solely from PiAV DNA, whereas all 12 serotypes of fowl adenoviruses (FAV1 to FAV12), some of them able to infect pigeons, did not react. A PCR fragment of 967 base pairs was amplified from three different isolates serologically typed as PiAV and from some pigeon liver samples showing morphological and histological signs of an adenovirus infection. Those samples did not react with a published primer pair (H3/H4) able to detect FAV, demonstrating the specificity of both PCRs to react exclusively with the respective pathogen, PiAV or FAV. The presented PCR is a suitable diagnostic tool to gain further insight into the epidemiology of PiAV infections in pigeons.

Adenoviridae Infections↗
PubMed2002

The pattern of cone pedicles and horizontal cells in the retina of the European anchovy, Engraulis encrasicolus L. (Engraulididae, Clupeiformes).

We have studied the architecture of polycone pedicles and their postsynaptic horizontal cells in the European anchovy using serial reconstruction by means of thin-sections from the cone outer segments to the outer plexiform layer. Within this layer there is a tesselated arrangement of pedicles in two strata, one made by the long-cone pedicles and one by those of the short-cones. The two pedicle types differ in the architecture of their synaptic sites. The long-cones possess two ribbon clusters corresponding to two bunches of subsynaptic dendrites, while the short-cones have only a single ribbon cluster innervated by a single group of dendrites. In addition, telodendria specifically connect the cone pedicles of neighbouring rows. Among the horizontal cells three classes arranged in separate levels can be distinguished. Serial reconstruction results suggest that first level horizontal cells contact long-cones preferentially. Among bipolar cells with an oval shaped dendritic field another type is found with a rectangular field of polycone-parallel dendritic combs. These findings indicate that the uncommon cone structures of engraulidids, which probably subserve polarization contrast vision, are correlated with a peculiar geometry of the outer plexiform layer.

Animals↗
PubMed2001

Mantle irradiation alone for pathologic stage I and II Hodgkin's disease: long-term follow-up and patterns of failure.

PURPOSE: We performed a retrospective study to determine the long-term outcome, patterns of failure, and prognostic factors for patients with pathologic Stage I or II Hodgkin's disease (HD) who were treated with mantle irradiation alone. METHODS AND MATERIALS: The medical records of 145 patients with pathologic Stage I or II supradiaphragmatic Hodgkin's disease treated with mantle irradiation alone between June 1967 and June 1991 were reviewed. Patterns of failure, overall survival (OS) rate, and progression-free survival (PFS) rate were determined. Univariate and multivariate analyses were performed to identify adverse prognostic factors for OS and PFS. The number of adverse prognostic factors per patient was counted, and a prognostic score was assigned to each patient. The log-rank test was used to compare the OS or PFS rates among patients with prognostic scores 0, 1, and 2. RESULTS: The median patient age was 27 years (range 10-66), with almost even male to female distribution. Every patient had splenectomy and negative laparotomy (LAP). Fifty-one patients had Stage I disease (IA-49, IB-2) and 94 Stage II (IIA-89, IIB-5). The histologic subtypes were nodular sclerosing in 110, mixed cellularity in 28, lymphocyte predominance in 5, lymphocyte depleted in 1, and unclassified in 1. Twelve patients with Stage II disease had >/= 3 sites of nodal involvement. Fifty-four patients had a prognostic score of 0, 70 of 1, and 21 of 2. The median follow-up time for the 109 surviving patients was 146 months (range 25-381). The 10- and 20-year actuarial OS rates for the whole group were 87.6% and 65.3%, respectively. The corresponding actuarial PFS rates were 75.3% and 74.2%, respectively. Thirty-six patients (9 Stage I, 27 Stage II) had relapses in a total of 41 sites. Failures by histology were 29 patients with nodular sclerosing, 6 with mixed cellularity, and 1 with lymphocyte predominance. Failures by sites were: trans-diaphragmatic, 22 (para-aortic nodes, 15; as the only site of progression in 12; visceral, 7; as the only site of progression in 5); within radiation field, 8; marginal miss, 8 (as the only site of failure in 2); and unknown, 3. The majority of the failures occurred within 5 years of diagnosis. Long-term side effects of radiation included cardiac complications in 30 patients, with 10- and 20-year actuarial cardiac complication rates of 12.6% and 35.1%, respectively; secondary solid tumors in 14, with 10- and 20-year actuarial rates of 2.3% and 25.7%, respectively; leukemia in 4; non- Hodgkin's lymphoma in 4, with the 10- and 20-year actuarial rates for leukemia and non-Hodgkin's lymphoma of 4.0% and 13.9%; and hypothyroidism in 38. Four adverse prognostic factors were identified for PFS: age > or = 40 years, > or = 3 sites of involvement, male sex, and constitutional symptoms. The prognostic score correlated with patients' outcome as indicated by PFS and OS rates. Patients with a prognostic score of 0 did significantly better than those with a score of 1 or 2. CONCLUSION: In this select group of patients with pathologic Stage I and II Hodgkin's disease treated with mantle irradiation alone, the OS and PFS rates at 10 and 20 years were comparable to those reported in the literature. The major pattern of disease progression was relapse below the diaphragm, therefore close surveillance of the abdomen is warranted. The prognostic score used in our series may predict the patient's outcome, and might be worth testing in a prospective trial. In our series, patients with a prognostic score of 0 had excellent long-term survival, indicating adequate treatment with mantle irradiation alone. Late complications of the treatment pose a significant threat for the patient's survival with long-term follow-up.

Adolescent↗
PubMed2001

Palmitoyl protein thioesterase (PPT) localizes into synaptosomes and synaptic vesicles in neurons: implications for infantile neuronal ceroid lipofuscinosis (INCL).

A deficiency of palmitoyl protein thioesterase (PPT) leads to the neurodegenerative disease infantile neuronal ceroid lipofuscinosis (INCL), which is characterized by an almost complete loss of cortical neurons. PPT expressed in COS-1 cells is recognized by the mannose-6-phosphate receptor (M6PR) and is routed to lysosome, but a substantial fraction of PPT is secreted. We have here determined the neuronal localization of PPT by confocal microscopy, cryoimmunoelectron microscopy and cell fractionation. In mouse primary neurons and brain tissue, PPT is localized in synaptosomes and synaptic vesicles but not in lysosomes. Furthermore, in polarized epithelial Caco-2 cells, PPT is localized exclusively to the basolateral site, in contrast to the classical lysosomal enzyme, aspartylglucosaminidase (AGA), which is localized in the apical site. The current data imply that PPT has a role outside the lysosomes in the brain and may be associated with synaptic functioning. This finding opens a new route to study the neuropathological events associated with INCL.

Animals↗
PubMed2001

Fine structure and development of the retina of the grenadier anchovy Coilia nasus (Engraulididae, Clupeiformes).

A study of the morphogenesis of the grenadier anchovy retina was undertaken using light and electron microscopy. Five developmental stages from prelarvae 3 days after fertilization to adult fish were studied. In addition to the general morphology of the eye and retina, special emphasis was given to the development of the photoreceptors and pigment epithelium (PE). The earliest retinae showing structural features indicative of a functioning eye are pure cone retinae composed of rows of alternating long and short cones forming a transient, tesselated pattern. At this stage there is a conventional PE containing melanin. In older stages cone rows are separated by the newly formed rods and by PE wedges filled with diffusely reflecting guanine crystallites. The findings are compared with the retinae of other engraulidids and with the development of teleost retinae in general. Moreover, the observed structural changes are discussed with respect to the photic habitat conditions of these anadromous fish that move between coastal waters, estuary, and river.

Animals↗