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The lens epithelium of the human eye plays a crucial role in the pathogenesis of primary and secondary cataract. Sixty hematoxylin-eosinstained lens epithelia were examined using a light microscope. Cell parameters were compared to one another in the various age groups of patients, between patients with secondary cataract (radiation cataract, steroid cataract and traumatic cataract) and patients with senile cataract, and between male and female patients. The t-test was used for statistical comparison. The median cell density was 3116.5 cells/mm2. The median nucleus-plasma ratio was 1:2.74. Patients with secondary cataract had a larger medium cell and nucleus area as well as a higher nucleus-plasma ratio and a lower cell density than patients with senile cataract. A part from degenerative and proliferative cell changes we found various cell types. The age of patients and the cause of cataract correlate with morphometric changes of lens epithelium cells. However, there was no correlation between specific cytologic changes and causes of cataract. 相似文献
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The ability of polymorphonuclear leucocytes (PMNs) to migrate into the different corneal layers in the presence or absence of a chemotactic stimulus was investigated in rabbits. The epithelial and/or endothelial surfaces were damaged in some corneas and in others they were intact. One side of the cornea was kept in contact with a viable population of rabbit PMNs and the other side with a chemotactic agent (zymosan activated human serum). The migration of PMNs into the cornea was traced histologically. The PMNs could not penetrate intact epithelium and Descemet's membrane even under the influence of a chemotactic stimulus. The stroma allowed PMN migration only when the chemotactic agent was present. The endothelium offered no resistance to PMN invasion whether the chemotactic stimulus was present or not. 相似文献
5.
AA Binhazim TA Rizvi LG Coghlan K Lew R Schmidt PK Wong 《Canadian Metallurgical Quarterly》1996,75(3):339-348
By serving as host recipients of xenografts from both humans and animals, severe combined immunodeficient (SCID) mice have become valuable to many laboratories interested in examining the pathophysiology of different diseases. To gain insight into the usefulness of the SCID mutation in retrovirus research, rhesus monkey fetal hematolymphoid tissues (liver and thymus) were used to construct a SCID-rhesus chimeric mouse (SCID-rh) and were engrafted in the renal capsule. The size and maturation of the thymic engrafts were monitored grossly, histologically, and immunologically. SCID mice were tolerant to rhesus tissues, and thymic engrafts contained thymocytes at different stages of maturation and differentiation that had morphologic features similar to age-matched rhesus thymus. Mature single positive CD2+, CD4+, and CD8+ T lymphocytes that were phenotypically similar to rhesus T lymphocytes were present at low levels (2% to 5%) in the peripheral blood and at moderately higher levels (7% to 15%) in the spleens of SCID-rh mice obtained between 12 and 15 weeks after thymus/liver engraftment. Within 3 weeks after engraftment, > 85% of the thymocytes in the thymic engrafts were immature double positive CD4+CD8+ T cells. The highest number of positive cells were seen in thymic engrafts obtained at 12 to 18 weeks. During these weeks, > 90% of the cells were double positive (CD2+CD4+, CD2+CD8+, and CD4+CD8+). After infection of the engrafted thymus tissue with simian immonodeficiency virus (SIVmac239), PCR analysis revealed successful viral infection of engrafts at 2 and 4 weeks after infection. No significant histopathologic and flow cytometric changes were observed in the thymic engrafts at 2 and 4 weeks after infection. An unrelated lesion of thymic lymphomas involving the SCID host thymus was seen in 12% of the mice. The data presented herein suggest that the SCID-rh is a valuable model for specific studies related to thymus-retrovirus interaction and that it could be used for further studies. The results are discussed in relation to current knowledge of thymus involvement during simian and human immunodeficiency virus infection. 相似文献
6.
D Denis-Henriot P de Mazancourt PK Goldsmith Y Giudicelli 《Canadian Metallurgical Quarterly》1996,8(3):225-234
Guanosine triphosphate (GTP)-binding protein subunits were studied by immunoblot analysis in particulate fractions from mature adipocytes, confluent preadipocytes, and in vitro-differentiated preadipocytes. Mature adipocytes express Gi alpha 1, Gi alpha 2, Gi alpha 3, Go alpha, Gq/11 alpha, G13 alpha and the long and short isoforms of Gs alpha, but no Gz alpha or G12 alpha. Confluent and differentiated preadipocytes differ in having a higher content of Gi alpha 3 and G13 alpha and expressing G12 alpha. In contrast, they lack Gi alpha 1, Go alpha, and the short from of Gs alpha. The G-protein alpha subunits Gi alpha 2, Gs alpha (long isoform), and Gq/11 alpha, and G-protein beta subunits were unchanged throughout the differentiation process. By immunoblot and indirect immunofluorescence studies on confluent preadipocytes, we showed that Gi alpha 2 is present in the endoplasmic reticulum and marginally in plasma membranes and nuclei. In contrast, antibodies to Gi alpha 3 stained the Golgi apparatus. The role of G proteins on preadipocyte proliferation was studied using Bordetella pertussis toxin. Exposure of growing cells to this toxin in the presence of fetal calf serum (FCS) decreased [3H]thymidine incorporation by 40% and induced a 40% increase in doubling time. This resulted in a 30% decrease in cell number per well after 48 h. These effects of B. pertussis toxin did not appear to be related to an increase in cyclic adenosine monophosphate (cAMP) concentration, because forskolin had the opposite effect on cell proliferation. Finally, B. pertussis toxin prevented serum-induced Raf1 association to the plasma membrane, possibly by disrupting FCS-induced G beta gamma effects on the Ras/Raf1 pathway. Since Go alpha and Gi alpha 1 subunits were absent in preadipocytes, we conclude that Gi2 and/or Gi3 proteins transduce some mitogenic signals of FCS through release of G beta gamma subunits. The subcellular distribution of Gi alpha 2 and Gi alpha 3 suggests that part of their functions result from interactions with components other than the plasma membrane. 相似文献
7.
JS Erjef?lt M Andersson L Greiff M Korsgren M Gizycki PK Jeffery GA Persson 《Canadian Metallurgical Quarterly》1998,102(2):286-294
In contrast to the protective effect of chronic caloric restriction on tumor development, we have shown that fasting sustained tumor initiation in rat liver by a noninitiating dose of diethylnitrosamine. Here we investigated whether fasting had a similar favorable effect on initiation in the colorectal mucosa in 80 male F344 rats. Animals fasted for 4 days were given a single s.c. dose of azoxymethane (AOM) (20 mg/kg) on the first day of re-feeding, and rates of kinetic proliferative parameters, and development of the pre-neoplastic lesions such as aberrant crypt foci (ACF), were evaluated. Starvation before AOM treatment enhanced the growth of ACF, as shown by the significantly higher crypt multiplicity of fasted/re-fed rats as compared with fully fed rats (3.97 +/- 0.50 vs. 2.64 +/- 0.20, p < or = 0.025). This difference was associated with perturbations in cell death and cell proliferation. Fasting induced apoptosis and depressed cell division, while re-feeding had opposite effects, resulting in a higher percentage of S-phase cells at the time of AOM injection and 2 days thereafter. Starvation-induced apoptosis may represent the mitogenic stimulus to an increase in the number of cells susceptible to AOM damage, and may favor its fixation, leading to enhanced growth of ACF. Our data therefore suggest that fasting/re-feeding enhances colon cancer. 相似文献
8.
The aim of this study was to investigate the effect of polymerization time and polymerization temperature on the residual methyl methacrylate (MMA) content of two heat-cured and two autopolymerized denture base polymers. Gas chromatography was used to determine the residual MMA content of three test specimens of each type of polymer. Increasing the polymerization temperature for the autopolymerized denture base resins from 30 degrees C to 60 degrees C decreased the residual MMA content of the polymer from an average of 4.6 wt% to 3.3 wt%. With the heat-cured denture base resins, a curing cycle at a polymerization temperature of 70 degrees C followed by a period at 100 degrees C significantly reduced the residual monomer content of the polymer when compared with a resin cured at 70 degrees C only. Polymerizing the heat-cured denture base resin at 100 degrees C only for various lengths of time significantly affected the residual MMA content of the polymer. The lowest residual MMA content (0.07 wt%) was obtained by polymerizing the heat-cured denture base resin at 100 degrees C for 12 h. The results of this study suggest that the polymerization temperature and polymerization time considerably affect the residual MMA content of denture base polymers. 相似文献
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A review on spectrum, frequency and complication rate of gastroenterological endoscopy in ambulant practice is given based on data of the National Association of Public Health Insurance Physicians of Germany. The following important aspects are mentioned: 1. Endoscopy has surpassed radiology in diagnostic examinations for gastric and colonic diseases. 2. Gastroscopy is more commonly carried out by physicians, coloscopy by gastroenterologists or specialists. Hospital doctors don't contribute significantly to ambulant endoscopic examinations of stomach and colon. 3. Endoscopic examinations of the pancreas, biliary tree, laparoscopy and other techniques play an insignificant role in ambulant practice. 4. The complication rate of ambulant gastroenterological endoscopy is very low. There have been only a few malpractice cases due to complications of gastroenterological endoscopic examinations. 5. The quality of coloscopy is not yet satisfactory as measured by the relative proportions of partial and total coloscopy. 6. In the past only limited attention was given to aspects of quality assurance and quality control in endoscopy in ambulant practice. This should be changed in the future. 7. The fees for gastroscopy and coloscopy allowed by the public insurance companies don't cover the expenses and are inadequate. As a result, a negative impact on the quality of medical care can be expected. 相似文献