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Biomedical subjects

A Weber

Publications and source records attributed to A Weber.

At least 325 records · Page 18Linked to original sources
PubMed1992

The histological nature of epulides in dogs.

The histological characteristics of a series of 154 oral tumours with the clinical appearance of epulides in 129 dogs were reviewed. Diagnoses were based on current criteria in human oral pathology and compared with the original diagnoses. The histological findings suggested that the majority of epulides in the dog can be classified as focal fibrous hyperplasia (43.5 per cent), peripheral ameloblastoma (17.5 per cent), peripheral odontogenic fibroma (WHO type) (16.9 per cent) and pyogenic granuloma (1.95 per cent). In addition, a number of other odontogenic tumours (1.95 per cent) and non-odontogenic tumours (18.2 per cent) such as fibrosarcoma and squamous cell carcinoma, which are not traditionally associated with the clinical appearance of an epulis, were diagnosed. Of 74 lesions that were previously diagnosed as fibromatous and ossifying epulides, 50 (68 per cent) were reclassified as focal fibrous hyperplasia and 21 (28 per cent) as peripheral odontogenic fibroma (WHO type). The majority of lesions (76 per cent), which were originally classified as acanthomatous epulis, were found to be peripheral ameloblastoma. In addition, three squamous cell carcinomas, two rare odontogenic tumours and two cases of focal fibrous hyperplasia were diagnosed in this classification. It was concluded that, as in man, the term epulis is a clinically descriptive term and that the renal nature of these lesions should be determined histologically.

Ameloblastoma↗
PubMed1992

Immunoassay principle based on exchange reactions: investigations on agarose gel and silanized quartz.

Preliminary studies of a new immunoassay principle based on exchange reactions is reported. Exchange of 125I-labelled insulin with unlabelled insulin from immobilized monoclonal antibodies was investigated. From antibody immobilized on a gel substrate the tagged insulin was exchanged according to a first-order process. With antibody immobilized on a quartz substrate by two different methods, the kinetics was changed dramatically, probably because of the non-specific interaction between the ligand and the surface. The recorded adsorption isotherms could not be described by the Langmuir adsorption equation, and a model allowing for non-specific adsorption of the ligand was developed. This model gave a satisfactory fit to the experimental data, allowing computation of adsorption parameters. It is concluded that even the best method used to immobilize receptors on quartz is not adequate for an exchange assay to be made. However, this coating method may lead to more sensitive receptor-based assays of more conventional type.

Adsorption↗
PubMed1992

Naloxone stimulation test in women with hypothalamic amenorrhea: a preliminary report.

We researched the possibility of the induction of ovulation by means of chronic opioid receptor blockade in 4 women with hypothalamic amenorrhea. Daily 4 mg naloxone were given as a bolus injection intravenously. By means of continuous determination of LH, FSH, 17-beta-estradiol (E2) and progesterone as well as of sonographic folliculometry follicular growth and subsequent ovulation should have been proved. Neither we found alterations of the basal values of LH, FSH, E2 and progesterone, nor we observed a follicular growth. These results lead us to the conclusion to put a naloxone stimulation test before further therapy. In this way opioid mediated hypothalamic ovarian insufficiencies can be registered and a therapy optimum can be reached early.

Adult↗
PubMed1992

How Listeria exploits host cell actin to form its own cytoskeleton. II. Nucleation, actin filament polarity, filament assembly, and evidence for a pointed end capper.

After Listeria, a bacterium, is phagocytosed by a macrophage, it dissolves the phagosomal membrane and enters the cytoplasm. The Listeria than nucleates actin filaments from its surface. These newly assembled actin filaments show unidirectional polarity with their barbed ends associated with the surface of the Listeria. Using actin concentrations below the pointed end critical concentration we find that filament elongation must be occurring by monomers adding to the barbed ends, the ends associated with the Listerial surface. If Listeria with tails are incubated in G actin under polymerizing conditions, the Listeria is translocated away from its preformed tail by the elongation of filaments attached to the Listeria. This experiment and others tell us that in vivo filament assembly must be tightly coupled to filament capping and cross-bridging so that if one process outstrips another, chaos ensues. We also show that the actin filaments in the tail are capped on their pointed ends which inhibits further elongation and/or disassembly in vitro. From these results we suggest a simple picture of how Listeria competes effectively for host cell actin. When Listeria secretes a nucleator, the host's actin subunits polymerize into a filament. Host cell machinery terminate the assembly leaving a short filament. Listeria overcomes the host control by nucleating new filaments and thus many short filaments assemble. The newest filaments push existing ones into a growing tail. Thus the competition is between nucleation of filaments caused by Listeria and the filament terminators produced by the host.

Actins↗
PubMed1992

New nuclide 263Ha.

Explore the source record for details and available documents.

Journal Article↗
PubMed1992

Diffuse peripheral odontogenic fibroma: report of 3 cases.

Since peripheral odontogenic fibroma (POF) is characteristically described as a solitary lesion and no diffuse POF had been reported in the literature, our cases should be considered as extremely unusual. Three diffuse cases of POF are described of which one case was seen in association with ocular and skin lesions. The question arises whether POF should be considered as a true odontogenic tumor rather than a diffuse hamartomatous lesion caused by uncontrolled induction of the gingiva. It is also possible that such lesions could be part of a yet undescribed syndrome.

Child↗
PubMed1992

Sequential changes in renal oxygen consumption and sodium transport during hyperdynamic sepsis in sheep.

The sequence of changes in systemic and renal oxygen delivery (QO2) and consumption (VO2) and renal function in an ovine model of progressive hyperdynamic sepsis was investigated. Nine chronically instrumented awake sheep were given a continuous intravenous Escherichia coli endotoxin infusion (20 ng.kg-1.min-1) for 3 days. After 8 h of the infusion, systemic arterial blood pressure and vascular resistance stayed decreased by 30% (P less than 0.001). Systemic QO2 progressively increased to a maximum of 157% of baseline values at 24 h and was associated with a decreased O2 extraction ratio from 33 +/- 2 (SE) to 23 +/- 2% (P less than 0.05), resulting in an unchanged systemic VO2. Renal blood flow and renal QO2 decreased by 40% during the first 12 h, returning to and staying at baseline values after 24 h. Renal VO2 decreased significantly by 35% at 12 h and then partially recovered to baseline values. Plasma creatinine clearance was maximally reduced to 25% of baseline values at 12 h and thereafter remained significantly (P less than 0.01) below 50% of baseline values. Both total and fractional sodium excretion fell at 12 h by 95 and 74%, respectively, and remained reduced over time, indicating conserved tubular function. The ratio of moles of sodium reabsorbed to moles of O2 consumed by the kidney was transiently reduced, from 33.4 +/- 4.1 to 12.4 +/- 3.6 at 12 h (P less than 0.05), indicating a relative increase in energy expenditure for tubular transport or renal synthetic activities, but recovered to baseline values after 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1992

Standards in monitoring acute experimental pancreatitis.

Animal models are helpful and irreplaceable tools in studying etiological factors and the pathogenesis of acute pancreatitis. For the comparability of the results, standards in monitoring of acute experimental pancreatitis are necessary. In this article an overview about different models of acute experimental pancreatitis and their severity are given. We also describe obligatory and facultative standard parameters in monitoring of acute experimental pancreatitis.

Acute Disease↗
PubMed1992

The closed duodenal loop technique.

The closed duodenal loop (CDL) technique, one of the first experimental models producing experimental acute pancreatitis, is described in this article. Since this model was published first by Pfeffer in 1957, it has undergone several modifications. The CDL method is an easily practicable and reproducible model to investigate acute hemorrhagic pancreatitis. In view of other available experimental models, the CDL technique has lessened in popularity.

Acute Disease↗
PubMed1992

Skull base dumbbell tumor: surgical experience with two adolescents.

Pediatric skull base tumors are rare and until recently were considered unresectable. We present two patients with tumors of similar anatomic position with an extracranial component in the infratemporal fossa and parapharyngeal space, an isthmus at the foramen ovale, and a superior component in the middle cranial fossa in the region of the cavernous sinus. A 15-year-old girl experienced contiguous spread of a spindle cell sarcoma; an 18-year-old boy developed a chondrosarcoma. A middle fossa approach provided the advantage of surgical avoidance of structures such as the middle ear and mastoid, facial nerve, and mandible. Postoperative recovery was rapid. Our impression is that preoperative carotid artery occlusion and a middle fossa approach for tumor resection can be performed in a young patient with acceptable morbidity and at least short-term benefit. Surgery can, therefore, provide an additional therapeutic approach to complement irradiation and chemotherapy.

Adolescent↗
PubMed1992

Five original recipes for strengthening hospital patient care.

Organizational innovation has a varied parentage--its famous mother being necessity--that can include the economic climate, marketplace characteristics, an organization's unique history and culture, leadership style, and corporate species. The following five Robert Wood Johnson Foundation/Pew Charitable Trusts grantees (see article, page 1) cast their own perspectives on approaches to strengthening nursing. The first three chose different emphases on programs built on existing practice models. The fourth hospital focuses on preparing the groundwork for major change, while the last looks outside at educating the youth who will eventually fill its caregiver roles.

Continuity of Patient Care↗
PubMed1992

Radiation-induced heart disease: morphology, changes in catecholamine synthesis and content, beta-adrenoceptor density, and hemodynamic function in an experimental model.

To study further the pathophysiology of radiation-induced cardiomyopathy, we investigated resting hemodynamics, myocardial catecholamine synthesis and storage, and beta-adrenoceptor density after local heart irradiation. In Wistar rats, a radiation dose of 20 Gy eventually leads to compromised myocardial function which is characterized by a reduction in cardiac output to 43 +/- 11% and in the left ventricular ejection fraction to 66 +/- 7.5%, and an increase in the left ventricular end-diastolic volume to 187 +/- 17% of control values. This reduction in function is correlated with focal degeneration of 23 +/- 4% of the myocardium. Measurement of tyrosine hydroxylase activity and catecholamine content revealed that catecholamine biosynthesis is unchanged in the adrenals but is significantly reduced in the hearts of irradiated animals, while cardiac beta-adrenoceptor density is increased to about 140% of that in age-matched controls. This is in contrast to findings in dilated or ischemic cardiomyopathy. Time-course studies showed that the development of myocardial degeneration starts simultaneously with the decrease in cardiac output and ejection fraction and the increase in beta-adrenoceptors at 50-80 days postirradiation. Myocardial degeneration is maximal in extent and severity at 100 days and does not progress thereafter. Cardiac output decreases at 80-100 days postirradiation to 60 +/- 7% of control values. A significant further decrease is seen only when congestive heart failure becomes manifest at 249 +/- 21 days after 20 Gy. Thus there is a delay between structural myocardial injury and hemodynamic deterioration which could be due to a compensatory increase in beta-adrenoceptor density during the initial stages of the cardiomyopathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Ocular manifestations of selected zoonoses in humans].

A report is given on the epidemiology and clinical signs of some selected zoonoses that may be of significance for ocular infections in man: brucellosis, leptospirosis, Lyme borreliosis, lymphocytic choriomeningitis, Newcastle Disease, ornithosis (chlamydiosis), rabies, Streptococcus suis infection, larva migrans ocularis by Toxocara canis or Baylisascaris procyonis, toxoplasmosis and tularemia.

Animals↗