Primary ciliary dyskinesia with situs inversus totalis, hydrocephalus internus and cardiac malformations in a dog

A nine-month-old golden retriever bitch was presented with exercise intolerance and recurrent nasal discharge. Based on clinical, radiographic and ultrasonographic examination, a diagnosis of rhinitis, situs inversus totalis and tricuspid valve insufficiency was established. The results of video- and electron microscopy studies of the respiratory epithelium were compatible with primary ciliary dyskinesia (PCD). However, no evidence of a primary ultrastructural defect of the cilia was found. The dog was euthanased because of the poor prognosis. At necropsy, a hydrocephalus internus and a subaortic stenosis were additionally diagnosed. PCD, in combination with situs inversus, has been previously reported in golden retrievers, but without a concomitant hydrocephalus internus. Furthermore, concomitant occurrence of internal cardiac malformation and PCD has not previously been reported in the dog.

In vitro effects and localisation of the photosensitizers m-THPC and m-THPC MD on carcinoma cells of the human breast (MCF-7) and Chinese hamster fibroblasts (V-79)

BACKGROUND AND OBJECTIVE

Photodynamic therapy (PDT) is the combination of a photosensitizer with laser light to induce preferential destruction of malignant cells. In this study two new photosensitizers--5,10,15,20-meta-tetra(hydroxyphenyl) chlorin (m-THPC) and m-THPC MethoxyPEG2000 derivative (m-THPC MD)--were tested, both for their dark toxicity, i.e., cytotoxicity in the absence of light, and for their light-induced cytotoxicity in mammalian cell cultures.

STUDY DESIGN/MATERIALS AND METHODS

Cell lines used were MCF-7 (human breast carcinoma) and V-79 (Chinese hamster lung fibroblast). After cultivation under standard conditions, cells were administered the photosensitizers and 24 hr later exposed to various energy levels of laser light at a wavelength of 652 nm. Cell survival was monitored using a clonogenic assay and was expressed as the surviving fraction of the untreated control.

RESULTS

Up to an m-THPC concentration of 1 microgram/ml, no dark toxicity was observed; at higher concentrations a rapid fall in survival occurred. m-THPC MD showed no dark toxicity up to 100 micrograms/ml. In vitro m-THPC was approximately 10 times more cytotoxic than m-THPC MD. The MCF-7 and V-79 cell lines displayed similar responses to PDT.

CONCLUSIONS

Both m-THPC and m-THPC MD are very efficient photosensitizers in vitro. Up to the therapeutic dose, neither exhibited dark toxicity. There is clinical relevance of the photosensitizers by a large therapeutic index.

Photodynamic effects in vitro in fresh gynecologic tumors analyzed with a bioluminescence method

Photodynamic therapy (PDT) is a promising alternative method for clinical cancer treatment. In the present study, cells from four breast carcinomas, seven ovarian carcinomas of various stages of differentiation, and ascites from a diffuse metastatic tumor were treated by PDT in vitro. Tetra(m-hydroxyphenyl)-chlorin (m-THPC) was used as the photosensitizer. Surviving cell rate was evaluated by the ATP-Cell-Viability-Assay (ATP-CVA), which measures light production as an interaction of intracellular ATP with the luciferin-luciferase complex. The most effective PDT of the tumor cells was achieved at an m-THPC concentration of 0.2 microgram/ml following incubation of the cells with photosensitizer for 24 hours. PDT toxicity resulted in a cell survival rate of 1% to 42% compared to untreated control cells (survival rate of control = 100%). The inhibitor concentration IC50 of m-THPC was determined both in the dark (dark toxicity) and in combination with laser irradiation. IC50 was defined as the concentration of photosensitizer which caused 50% of cell death. The IC50 values were heterogeneous in all tumor specimens examined. IC50 values for dark toxicity were on average 0.14 microgram m-THPC/ml for primary ovarian carcinoma, 2.16 micrograms m-THPC ml for refractory ovarian carcinoma and 0.3 microgram m-THPC/ml for breast carcinoma. After PDT, average IC50 value for refractory ovarian carcinoma was 0.04 microgram m-THPC/ml, for primary ovarian carcinoma 0.05 microgram m-THPC/ml and for breast carcinoma 0.03 microgram m-THPC/ml. These data might indicate that clinical PDT of gynecological carcinoma requires individual treatment conditions to achieve optimal results.

m-THPC-mediated photodynamic therapy (PDT) does not induce resistance to chemotherapy, radiotherapy or PDT on human breast cancer cells in vitro

Photodynamic therapy (PDT) uses laser light to activate a photosensitizer that has been absorbed preferentially by cancer cells after systemic administration. A phototoxic reaction ensues resulting in cell death and tissue necrosis. Some cells, however, may survive PDT. This study was performed to determine if surviving human breast cancer cells (MCF-7) can become resistant to PDT, chemotherapy or radiotherapy. The MCF-7 cells were cultured under standard conditions prior to being exposed to the photosensitizer, 5,10,15,20-meta-tetra(hydroxyphenyl)chlorin (m-THPC), for 24 h and then irradiated with laser light (652 nm). Surviving cells were allowed to regrow by allowing a 2 week interval between each additional PDT. After the third and final treatment, colony formation assays were used to evaluate the sensitivity of cultured cells to ionizing radiation and PDT and the ATP cell viability assay tested in vitro chemosensitivity. Flow cytometry was used to analyze the cell cycle. No alterations in the cell cycle were observed after three cycles of PDT with m-THPC. Similar responses to chemotherapy and ionizing radiation were seen in control and treatment groups. The m-THPC-sensitized PDT did not induce resistance to subsequent cycles of PDT, chemo- or radiotherapy. Photodynamic therapy with m-THPC may represent a novel adjunctive treatment of breast cancer that may be combined with surgery, chemotherapy or ionizing radiation.

Stimulation of peripheral nerve regeneration by an isolated nerve segment

An experimental model in rats was used to assess the stimulant effect of an isolated nerve segment on peripheral nerve regeneration. In a first group of animals, 14 mm of the femoral nerve was removed unilaterally and the gap was bridged with femoral vein taken from the other side. In a second group, the intervention differed in that a 2-mm nerve segment was introduced at the center of the bridging vein. Histological examination was done three months after the operation. In the first group, a newly formed nerve structure was found in the proximal part of the vein, with incipient myelination of nerve fibers. The frequency of nerve fibers decreased with the distance from the proximal nerve stump, with no fibers present in the distal part of the vein. In the second group, a well-developed nerve structure was noted in both the proximal and the distal parts of the bridging vein, with myelination well advanced. Possible reasons for the positive effect of an isolated nerve segment in bridging nerve gaps are discussed.

Spontaneous anastomosis of vessels approximately 100 mu in diameter: an experimental study

Spontaneous anastomosis of vessels approximately 100 mu in diameter was studied in experiments on rats. The vessels--both arteries and veins--were transected and the stumps joined with a suture. In the veins, a fully functional anastomosis developed within 5 to 7 days after the intervention. Spontaneous anastomosis was, however, relatively uncommon with arteries and also took longer. The experiments support the view that anastomosis is governed by chemotaxis.