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Biomedical subjects

A Schramm

Publications and source records attributed to A Schramm.

At least 55 records · Page 3Linked to original sources
PubMed1995

Characterization and chromosomal assignment of yeast artificial chromosomes containing human 3p13-p21-specific sequence tagged sites.

Human chromosomal region 3p12-p23 is proposed to harbor at least three tumor suppressor genes involved in the development of lung cancer, renal cell carcinoma, and other neoplasias. In order to identify one of these genes we defined sequence tagged sites (STSs) specific for 3p13-p24.2 by analyzing a chromosome 3p14 microdissection library. STSs were used for isolating yeast artificial chromosome (YAC) clones from the Centre d'Etude du Polymorphisme Humain (CEPH) YAC libraries. Thirty-eight YACs were assembled into a contig approximately 2.5 Mb in size spanning the t(3;8) and t(3;6) translocation breakpoints associated with hereditary renal cell carcinoma and hematologic malignancies, respectively. Chromosomal localization and chimeric status of 126 YACs was analyzed by fluorescence in situ hybridization (FISH). The order of 17 YACs determined by double-color FISH was in agreement with the STS-based arrangement of the YAC-contig.

Base Sequence↗
PubMed1995

Homozygous loss of the MTS1/p16 and MTS2/p15 genes in lymphoma and lymphoblastic leukaemia cell lines.

The genes MTS1/p16 and MTS2/p15 located in 9p21 encoding cyclin-dependent kinase-4 inhibitors are homozygously deleted in a number of different tumour cell lines. By PCR analysis of 30 cell lines, including 10 acute lymphoblastic leukaemia (ALL) and 20 lymphoma cell lines, we found homozygous deletions of at least one locus in 11 (37%) cell lines. MTS1-specific sequences were deleted in 70% of ALL (reaching 86% in T-cell ALL) but in none of the non-Hodgkin's lymphoma (NHL) cell lines. MTS2-specific sequences were deleted in 40% of ALL and 17% of NHL cell lines. We observed a higher frequency of MTS1 deletions in ALL than in NHL (P < 0.001) and in T-cell neoplasms compared to B-cell neoplasms (67% v 6%; P = 0.001). In ALL-derived cell lines deletions of the MTS2 gene only occurred in cases with MTS1 deletions but in NHL only in cases without MTS1 deletions.

Base Sequence↗
PubMed1994

[The corroborative capacity and value of imaging diagnosis and duplex sonography in newborn infants with necrotizing enterocolitis].

In this prospective study 101 sonographic examinations of superior mesenteric artery blood flow velocities, indices and blood flow volume were consecutively performed in 41 newborn to diagnose necrotising enterocolitis (NEC). Intramural and portal venous gas was also estimated. The artifacts of air in the AMS and the portal system were examined in an experimental study. The results of sonography and abdominal radiography were equivalent in the case of definitely established NEC, portal venous gas being more sensitive to detection by sonography. Abdominal radiography was indicated as the primary examination in case of a clearly identified clinical course. Sonography should be performed so that fewer radiographs will be required in the following course of disease.

Abdomen↗
PubMed1992

Effect of yohimbine on renal sympathetic nerve activity and renal norepinephrine spillover in anesthetized rabbits.

The function of presynaptic alpha-2 adrenergic autoinhibition of norepinephrine release was studied in anesthetized rabbits (alfadolone + alfaxalone) with uninterrupted sympathetic impulse traffic. The animals received a tracer infusion of [3H]norepinephrine i.v. Arterial and renal venous concentrations of endogenous norepinephrine and [3H]norepinephrine, the firing rate of the renal sympathetic nerves and renal blood flow were determined. The results were used to calculate the renal fractional [3H]norepinephrine extraction, the renal removal and spillover of norepinephrine, the total body [3H]norepinephrine clearance and total body norepinephrine spillover. Sodium nitroprusside (10-80 micrograms kg-1 min-1 i.v.), which was infused to modulate sympathetic activity through the baroreceptors, caused hypotension and increased the renal sympathetic firing rate and the renal as well as total body norepinephrine spillover. Increases of total body norepinephrine spillover were much higher than increases of renal spillover. Yohimbine (1 mg kg-1 + 0.2 mg kg-1 hr-1 i.v.) caused slight central sympathoexcitation. In addition, it enhanced the renal and total body spillover of norepinephrine at any given firing rate of the renal sympathetic nerves. The distinguishing feature of this study is the measurement of sympathetic firing rate and norepinephrine spillover in one and the same organ, the kidney. The results demonstrate that the alpha-2 adrenergic autoinhibition of norepinephrine release normally operates in the kidney with intact sympathetic impulse traffic. They also suggest its operation in other peripheral sympathetically innervated tissues.

Anesthesia↗
PubMed1991

[Medical problems in the care of the elderly].

The number of long-lived persons is increasing dramatically. They have a high need for medical help and make high demands on their doctors, especially because of their extreme physical, psychological and social multimorbidity. It is difficult but important to assess the vital energy and the life expectancy of these persons living near death. The spectrum of vitality ranges from admirably well-preserved persons without any need of help to bedridden sick people wasting away. In this paper, there are discussed specific findings and opportunities of intervention, in particular the problems of admission to hospital and life-lengthening measures.

Aged↗
PubMed1991

[Acute methanol poisoning--a review and a case report].

Acute methanol intoxications are infrequent among accidental or suicidal intoxications today. The characteristic findings are illustrated by a review. Mainly, the methanol metabolites formaldehyde and formic acid are of toxicologic importance and cause the dominant central nervous and ocular symptoms. The principal therapeutic procedures include gastric lavage, induced vomiting, titrated correction of acidosis with sodium bicarbonate, administration of ethanol, folic acid and, especially, the secondary detoxication with peritoneal--or better--haemodialysis. The therapeutic measures must be started quickly and carried out consequently to improve the prognosis of methanol intoxication and to decrease the frequency of serious late complications like ophthalmologic and neurologic lesions. Our own medical management is described by a case report treated successfully.

Adult↗
PubMed1991

[The significance of internal medicine intensive care within the complex of intensive medicine. Discussion contribution to the structural and professional classification in adult intensive medicine].

The development and establishment of intensive care units for adult patients requires a far-reaching subdivision into surgical and conservatively oriented intensive care for qualitative and quantitative reasons. Insufficiently substantiated claims to monopolization of intensive care techniques that are polemically asserted have to be strongly contradicted. The present paper is concerned with approved structural concepts of intensive care developed by Deutsche Krankenhausgesellschaft and various medical societies. They are supplemented by personal experience in the field of internal intensive care.

Adult↗
PubMed1990

[MRT of tumors of the larynx and hypopharynx using Gd-DTPA: clinical value].

Thirty one patients with tumours of the larynx and hypo-pharynx were studied by MRI, both with and without the para-magnetic contrast medium, GD-DTPA. The results were compared with pre-operative laryngoscopy and the final pathological tumour classification. The most accurate results were obtained by comparing T1-weighted sequences before and after the use of GD-DTPA. Because of the relatively rapid mode of examination and the specific enhancement, the method proved ideal for evaluating tumours of the larynx and hypo-pharynx. MRI is a valuable diagnostic technique for staging and treatment planning of patient with tumours of the larynx and hypo-pharynx.

Contrast Media↗
PubMed1990

[Electrical impedance and time of death in the animal model].

To study passive electric parameters of the rat skeletal muscles in relation to the time of death, investigations were carried out using the impulse distortion method of Pliquett. This measuring method enables the evaluation of the electric rectangular impulse distorted by the biological tissues, which contains any essential information on the passive electric properties of the object to be measured. The passive electric parameters change in the studied time interval up to 79 h post mortem in a characteristic fashion. The linear correlation of the evaluated impulse parameters at the time of death is closest (r = 0.75) between 0.5-8.5 h post mortem, the scatter of single values in late postmortal periods is in part considerable. A further development of the measuring technique and standardization of the measuring method let the passive electric parameters appear to be appropriate magnitudes for estimating the time of death.

Animals↗
PubMed1989

[Laser light-induced cytotoxicity of cultivated squamous cell cancer cells of the head and neck following photosensitization].

Photodynamic therapy, which involves the action of light-activated dyes on biological tissues, has been attempted to treat tumors. In order to achieve effective tumor cell destruction in head and neck cancer, the direct photodynamic effects on in vitro cultured squamous carcinoma cell lines were analyzed. Without light no tumor cell killing was observed after photosensitization up to 6 hrs with dihematoporphyrinester/-ether (DHE) concentrations of 5 micrograms/ml. With longer incubation times and higher light irradiation dosages, however, an increasing cytotoxicity could be observed. Optimal intervals for photosensitization were 48 hours. Squamous cell carcinoma lines of the head and neck from different locations did not differ in their photodynamic behaviour with respect to photodynamic treatment. With the results presented, it will be appropriate to complete in vivo studies to inspire photodynamic tumor cell destruction in the treatment of head and neck cancer as a new approach besides the classical therapeutic modalities.

Carcinoma, Squamous Cell↗
PubMed1988

[Photodynamic destruction of in vitro cultivated squamous cell carcinoma cells of the head and neck area].

Hematoporphyrin derivatives are retained in higher concentrations in proliferating tumor tissues than in normal tissues causing a defined photosensitization. Laser light irradiation of photosensitized cells results in photobiological, non-thermal cell destruction. These photodynamic reactions were analyzed with in vitro cultured squamous cell carcinoma lines of the head and neck. As a light source we used an argon-ion-pumped-dye laser (630 nm wavelength), and for photosensitization we employed a mixture of dihematoporphyrinester and -ether (DHE). The photodynamic reaction on squamous carcinoma cells was proportional to the DHE concentration, the DHE incubation time, and the light exposure. Maximal tumor cell destruction in comparison to DHE free controls was observed with DHE concentrations of 5-10 micrograms/ml medium and a light exposure of 2-4 Joule/cm2. Based on these dose effect relations for DHE sensitized squamous carcinoma cells, photodynamic therapy for destruction of head and neck cancer can be applied in animal tumor models.

Carcinoma, Squamous Cell↗
PubMed1985

Temporal correlation of some endocrine circadian rhythms in elderly subjects.

The aim of this chronobiological study was to investigate temporal correlations in the circadian patterns of 6 hormones, namely somatotrophic hormone (STH), prolactin (PRL), cortisol (F), aldosterone (ALD), insulin (IRI) and C-peptide (CP), assayed in systemic blood serum drawn at 07:00, 10:00, 13:00, 16:00, 19:00 and 22:00 h from an antecubital vein in 19 young subjects (aged 20-29 yr, comprising 10 males and 9 females; and 20 elderly subjects (aged 70-81 yr, comprising 10 males and 10 females). All subjects were sampled on a normal dietary sodium intake (120-140 mEq/24h) while following a social routine of diurnal activity (07:00-23:00) and nocturnal rest (23:00-07:00). Time-qualified data were analyzed by lead-lag correlation and by cosinor analysis. According to the lead-lag correlation findings, it would appear that the correlation which exists between several time-qualified series in young subjects is no longer present in elderly subjects. The circadian rhythms which were found to have lost their temporal correlations with advancing age were those between STH and IRI, STH and ALD, PRL and IRI, PRL and CP, and ALD and CP. It should be noted that the correlation between hormonal rhythms breaks down mainly on account of a peculiar age-related change in the magnitude of the circadian fluctuation. This chronological decline in amplitude led to the conclusion that the senescence of endocrine rhythmic functions is a biological phenomenon characterized by altered circadian variability.

Adult↗
PubMed1984

[Comparative study of the effect of the calcium antagonist nifedipine, the beta receptor blockers acebutolol and propranolol and their combination on electrophysiologic parameters in the human].

It is well known that in the isolated atrium, nifedipine, verapamil and diltiazem slow down the spontaneous frequency and conduction velocity in the sinus- and in the atrioventricular node. Using therapeutic doses in man, we studied the influence of the calcium-antagonist nifedipine, the beta-blockers acebutolol and propranolol and a combination of these on sinus-node parameters (spontaneous cycle length AA, sinus-node recovery time SNRT, corrected sinus-node recovery time CSNRT, sinoatrial conduction time SACT), and on the intracardiac conduction time (PA-, AH-, HV-interval). Both beta-blockers slowed the spontaneous frequency of depolarization of the sinus-node, but lengthened sinus-node recovery time and sinoatrial conduction time (acebutolol: AA + 6% n.s.; SNRT +5% n.s.; CSNRT +2% n.s.; SACT +33% s.; propranolol: AA +9% n.s.; SNRT +15% s.; CSNRT +37% n.s.; SACT +32% n.s.). Simultaneously PA-, AH and HV-interval lengthened (acebutolol: PA +16% n.s.; AH +7% s.; HV +15% s.; propranolol: PA +19% n.s.; AH +16% s.; HV +9% s.). Nifedipine caused essentially no change in sinus-node parameters nor in intracardiac conduction time in man (AA -11% s.; SNRT -12% s.; CSNRT -7% n.s.; SACT +35% n.s.; PA +4% n.s., AH -2% n.s.; HV +5% n.s.). This is in contrast to results obtained in the isolated atrium, and is different from other calcium-antagonists such as verapamil, gallopamil and diltiazem. The effect of acebutololinduced beta-blockade is not intensified by nifedipine (AA -3% n.s.; SNRT -6% s.; CSNRT -12% s.; SACT -19% n.s.; PA -5% n.s.; AH +3% n.s.; HV +9% n.s.).

Acebutolol↗
PubMed1983

Circadian as well as circannual rhythms of circulating aldosterone have decreased amplitude in aging women.

Age differences in the characteristics of the circadian rhythm in circulating radioimmunoassayable aldosterone were studied on nine 20 to 26 year-old and ten 70 to 78 year-old women and ten 23 to 26 year old and ten 70 to 80 year old men in Würzburg, West Germany. These diurnally active-nocturnally resting subjects were sampled every 3 hours for 15 hours. A classical analysis of variance and a multivariate analysis of rhythm characteristics revealed major effects of age exerted on the circadian aldosterone amplitude in women (p = 0.003) but not in concomitantly sampled men. These observations complement the study of circadian and circannual rhythms in 8 young adults (15-21 years), 10 mature adults (29-36 years) and 10 post-menopausal (44-59 years) North American women, sampled at 100 minute intervals for 24 hours, once in each season, and document that the adrenocortical aldosterone-producing system remains rhythmic with at least two frequencies up to the late decades of human life, although in women it may be characterized by a reduction in the extent of spectral change after 70 years of age.

Adult↗