Influence of Experimental Parameters on Fatigue Crack Growth and Heat Build-Up in Rubber

Loading parameters (frequency, amplitude ratio and waveform) are varied to determine their influence on fatigue crack growth in rubber. Up to three different rubber blends are investigated: one actual engineering material and two model materials. Fatigue crack growth curves and strain distributions of pure shear and faint waist pure shear samples are compared for a model material. Fatigue behavior is studied for three different frequencies (1 Hz, 3 Hz and 5 Hz). Amplitude ratio appears to be another important influence factor concerning fatigue crack growth in rubber. The beneficial effect of positive amplitude ratios (tensional loading conditions) is shown for different materials. However, fatigue crack growth is considerably increased for negative amplitude ratios (tensional-compressional loading conditions). Furthermore, the influence of the waveform is determined for three different waveform shapes. One is sinusoidal, and two have a square shape, including dwell periods and sinusoidal slopes. Special focus lies on heat build-up, which is substantial, especially for large loads, high frequencies and/or highly filled rubber blends. Plateau temperatures are determined for various loading conditions and rubber blends. A very simple linear relationship with dissipated energy per time and unit area is obtained. Results gathered with dynamic mechanical analyses show, likewise, a linear trend, but the heat build-up is very small, due to different sample geometries.     

Ultrastructural and immunohistochemical characteristics of lipid-rich carcinoma of the breast

Summary Five cases of lipid-rich carcinomas of the breast were investigated ultrastructurally and immunohistochemically for alpha-lactalbumin (ALA), lactoferrin (Lfr) and human milk fat globule membrane antigen (HMFG-2). Staining for ALA and Lfr showed intensive reaction on nearly all of the tumour cells whereas immunoreaction for HMFG-2 revealed positivity in single cells. All tumours were negative for steroid receptor content. Ultrastructurally the tumour cells showed numerous intracytoplasmic non-membrane bound lipid droplets which were often found within autophagocytic vacuoles. Neither rough endoplasmic reticulum nor Golgi complexes showed any sign of lipid synthesis. Extrusion of lipid droplets and extracellular lipid deposition was not observed. In conclusion, our findings do not justify the consideration of lipid-rich carcinoma of the breast as a clearly defined group of tumours with specific secretory activity. Therefore, the term lipid-rich carcinoma should be used in preference to lipid-secreting, unless there is evidence of active lipid secretion.     

Zerebrale Angiographie bei komplizierter Migraine — Reaktionen,Zwischenfälle

Summary Seventy-one patients (ages: 15–58 years) suffering from complicated migraine were investigated by means of cerebral angiography which was not performed during an attack. Angiography was carried out to exclude stenoses or occlusions of the cranio-cervical vessels and above all vascular malformations (arterial aneurysms, arteriovenous angiomas). In 18 cases (25.4%) organic lesions were found, including three vessel malformations (4.2%). Thirty-one patients (43.7%) suffered from headache reactions or other complications during or within 24 h following angiography. In 15 cases (21.1%) attacks of complicated migraine were observed, three patients (4.2%) suffered from headache and bilateral flickering visual disturbances, another 11 patients (15.5%) developed headache and vegetative symptoms requiring therapeutic management. One patient (1.4%) got an epileptic seizure, another patient (1.4%) developed a generalized urticaria exanthema. There were more headache reactions in women than in men. However, the highest percentage of reactions was observed in patients in whom migraine headache had occurredclearly set off from the transient cerebral functional disturbances. Neurological complications (transient functional disturbances) occurred in 16 of 71 patients (22.5%). The neurological complication rate was significantly (P < 0.001) higher than that in an unselected group of patients (3.0%). However, apart from one case with an acute organic psychosis and permanent amnesia during the angiographic investigation and the postangiographic period, only transient functional disturbances without permanent deficits were seen. In view of the benign course of the complications, it is our opinion that in spite of the high rate of headache reactions angiography should be performed in patients with complicated migraine. Cerebral angiography is the only method of reliably diagnosing intracranial arterial stenoses, occlusions and vascular malformations. Without angiography and thus without diagnosis patients would be considerably endangered (possible rupture of the malformation with fatal consequences).

     

Estrogen receptor analysis on biopsies and fine-needle aspirates from human breast carcinoma. Correlation of biochemical and immunohistochemical methods using monoclonal antireceptor antibodies.

Monoclonal antibodies against estrogen receptor (ER) were used for determination of ER status immunocytochemically in histologic specimens from 192 primary breast carcinomas. All tumors were also assayed biochemically for ER with the dextran-coated charcoal method (DCC). The comparison of biochemically and immunocytochemically determined ER status showed concordant results in 80% (P less than 0.0001). In only 2 cases (1%) with low ER levels (less than 20 fmol/mg protein) immunocytochemistry failed to detect ER. ER positivity determined with a semiquantified approach based on intensity and heterogeneity of immunocytochemical staining correlated significantly with biochemically determined ER levels (P = 0.0001). In a series of fine-needle aspirates of 34 breast carcinomas sufficient cell material was available for ER immunocytochemistry (ER-ICA). Overall, the results of ER-ICA in fine-needle aspirates were concordant with ER-ICA in histologic specimens in 88% of the samples. In a few cases with weak positivity of ER-ICA in histologic specimens, ER-ICA was negative in fine-needle aspirates. In no case was there a false-positive immunocytochemical ER determination in a tumor aspirate. Thus, ER-ICA seems to be a reliable assay which can be performed in histologic and cytologic specimens.     

Untersuchung zur Frage von persistierenden Veränderungen der Fibrinolyseparameter t-PA und PAI bei Patienten nach juvenilem ischämischen cerebralem Insult

Summary In diseases associated with thrombotic or thromboembolic complications, a reduction in the fibrinolytic potential may contribute to the risk to develop thrombosis.To investigate whether iuvenile cerebral infarction is associated with a permanent defect of the fibrinolytic system we measured the main components of the fibrinolytic system, tissue plasminogen activator (t-PA) and its fast acting inhibitor (PAI) in plasma samples of 21 patients (aged 21–44 years) 3–24 months after the acute event. The data obtained were compared to those from thirteen healthy young volunteers (22–46 years). A direct effect of known risk factors on the fibrinolytic system could be excluded because patients avoided their risk factors immediately after the ischemic cerebral attack. Hypertension and the combination of oral contraceptives and smoking had been the most striking original risk factors.Levels of t-PA antigen and t-PA activity before and after venous occlusion, or PAI activity were not different between patients and controls suggesting that at least a permanent decrease in the activity of the fibrinolytic system does not exist in these patients. However, our findings do not exclude that a temporary defect in fibrinolysis might have contributed to the acute onset of the thrombotic cerebral event possibly induced by the risk factors originally present.

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Abkürzungen t-PA tissue plasminogen activator - PAI plasminogen activator inhibitor - RIND reversibles ischämisches neurologisches Defizit - KS kompletter Schlaganfall - TIA transitorisch ischämische Attacke     

Cochlear implantation in adults with single-sided deafness: generic and disease-specific long-term quality of life

European Archives of Oto-Rhino-Laryngology - To determine the 2-year outcome of health-related quality of life (HRQoL) in adults who received a cochlear implant (CI) for single-sided deafness...     

In situ proliferation contributes to accumulation of tumor‐associated macrophages in spontaneous mammary tumors

Infiltration of a neoplasm with tumor‐associated macrophages (TAMs) is considered an important negative prognostic factor and is functionally associated with tumor vascularization, accelerated growth, and dissemination. However, the ontogeny and differentiation pathways of TAMs are only incompletely characterized. Here, we report that intense local proliferation of fully differentiated macrophages rather than low‐pace recruitment of blood‐borne precursors drives TAM accumulation in a mouse model of spontaneous mammary carcinogenesis, the MMTVneu strain. TAM differentiation and expansion is regulated by CSF1, whose expression is directly controlled by STAT1 at the gene promoter level. These findings appear to be also relevant for human breast cancer, in which an interrelationship between STAT1, CSF1, and macrophage marker expression was identified. We propose that, akin to various MU subtypes in nonmalignant tissues, local proliferation and CSF1 play a vital role in the homeostasis of TAMs.     

Histological grading of therapy induced regression in squamous cell carcinomas of the oral cavity. A morphological and immunohistochemical study

Squamous cell carcinomas in the oral cavity and the oropharynx were diagnosed in 84 patients. After verification by biopsy, 79 of these patients were treated preoperatively with mitomycin C and 5-fluro-uracil, radiated and operated 3-5 weeks later. The effectiveness of adjuvant preoperative radio-chemotherapy was evaluated histologically. Serial sections of the entire tumor specimen were investigated and the percentage of vital cancerous tissue in the total tumor area was assessed. Regression was classified into four grades. Grades I and II were regarded as good response to adjuvant preoperative radio-chemotherapy, while grades III and IV stood for bad or no response. Morphologically questionable residual tumor infiltrates could be clarified by immunohistochemical methods with antibodies against vimentin, desmin and Lu-5. The histological assessment of the regression grade of operated tumor specimens allows a clinically relevant, morphologically exact and reproducible evaluation of the effect of preoperative radiochemotherapy.