Characteristics of histamine release from rat mast cells induced by a bracken toxin, braxin A1.

The effect of braxin A1, a new bracken glucoside, on histamine release from isolated rat peritoneal mast cells was studied. Braxin A1 caused the release of histamine in a dose-dependent manner; the release was slow and increased gradually with time, finally reaching a maximum release of 100%. The action of braxin A1 depended on the incubation temperature in the range from 4 degrees C to 49 degrees C, while it was almost abolished at 0 degree C. The action of braxin A1 was unaffected by removing calcium or any inorganic ions from the incubation medium and by the addition of 2,4-dinitrophenol or theophylline. The mast cells exposed to braxin A1 were vitally stained with trypan blue and swelled greatly. The cell swelling was characterized by the protrusion of swollen cytoplasmic granules. The present results for braxin A1 were similar to those for the ionophore X537A except for the extracellular inorganic ion dependency, but they were different from those observed with compound 48/80. These results suggest that braxin A1 releases histamine from mast cells without both exocytosis and membrane lysis, but with a cytotoxic action on cytoplasmic membranes by a different mode of action from that of X537A.     

Pars plana vitrectomy for epiretinal membrane associated with sarcoidosis

PURPOSE: To examine retrospectively the visual outcomes in patients undergoing vitrectomy for epiretinal membranes secondary to sarcoid uveitis. METHODS: Eleven consecutive patients (11 eyes) with epiretinal membrane and uveitis associated with sarcoidosis underwent pars plana vitrectomy. RESULTS: Nine eyes (82%) gained two or more lines of Snellen visual acuity at 1-12 months after surgery. However, 4 of these 9 eyes lost two or more lines of Snellen visual acuity by the final visit. Overall, 5 eyes (45%) had attained at least two Snellen lines of visual acuity improvement, 5 eyes (45%) were unchanged, and 1 eye (10%) had worsened by two lines at the final visit. Nine eyes (81%) achieved visual acuity of 20/40 or better by the final visit. Slit-lamp biomicroscopy and fluorescein angiography showed that cystoid macular edema had resolved in 4 of 7 eyes postoperatively; vitritis improved in all cases. Postoperative complications included cataract formation, glaucoma, and membrane recurrence. Subsequent surgeries consisted of cataract extraction in 2 eyes and membrane peeling in 1 eye. CONCLUSIONS: Pars plana vitrectomy appears to have a beneficial effect on restoring vision in eyes with epiretinal membrane and uveitis associated with sarcoidosis, but final visual acuity was limited by the development of cataract and membrane recurrence.     

Down-regulation of p21Waf-1 protein facilitates IR- and UV-induced apoptosis in human squamous carcinoma cells

DNA damage via radiation exposure and administration of chemotherapeutic agents induce apoptosis, which is a basic mechanism for non-surgical anti-cancer treatment. We analyzed ionizing radiation (IR)- or ultraviolet (UV)-induced apoptosis in human laryngeal carcinoma (HEp-2) and uterine cervical carcinoma (HeLa) cells, and found that HeLa cells were significantly more sensitive to both IR- and UV-induced apoptosis compared to HEp-2 cells, in spite of the same histological type and p53 status. The cyclin-dependent kinase (Cdk) inhibitor, p21Waf-1 was modified differently between the two cancer cell types, whereas p53 protein was induced in a similar manner after IR or UV treatment. IR steadily induced p21Waf-1 protein in HEp-2 cells, but not in HeLa cells. Additionally, p21Waf-1 protein recovered close to the basal level only in HEp-2 cells, although UV caused rapid, dramatic and caspase-independent reduction of p21Waf-1 protein in both cancer cells. Furthermore, overexpression of p21Waf-1 protein in these cells by transient transfection and in stable cell lines in a tetracycline-regulated system, rescued IR- and UV-induced apoptosis. Finally, suppression of p21Waf-1 protein using antisense oligodeoxynucleotide transfection facilitated UV-induced apoptosis in both HEp-2 and HeLa cells. We concluded that p21Waf-1 protein is modified independently of p53 and functions as an inhibitor of IR- as well as UV-induced apoptosis in squamous carcinoma cells.     

Prostaglandin E2 excites neurons of the nucleus tractus solitarius by activating cation channels

Nucleus tractus solitarius (NTS) has a high density of prostaglandin E₂ (PGE₂)-binding sites. Action of PGE₂ (10⁻⁹–10⁻⁶ M) was tested on neurons in a NTS slice with patch-clamp recording under synaptic blockade. PGE₂ raised the firing rate in approximately half of the neurons in cell-attached patch mode. In whole-cell current clamp, PGE₂ depolarized membrane potential accompanied by an increase in firing rate. In whole-cell voltage clamp (−58 mV), PGE₂ induced the inward current with an increase in conductance. The current was linearly related to voltage from −100 mV to −10 mV and suppressed between −10 mV and 20 mV. The current-voltage curve remained similar under low external Cl⁻ or high internal Cl⁻ conditions and after external Na⁺ was replaced by Cs⁺. It is concluded that PGE₂ excites NTS neurons by activating cation conductance.     

Gene rearrangement studies on lymphoma of the lung: Report of a case

We describe herein how true lymphoma of the lung was differentiated from pseudolymphoma in a 45-year-old woman presenting with pulmonary infiltrates. Although segmental resection revealed typical histologic findings of pseudolymphoma of the lung and immunohistochemical studies did not demonstrate a monoclonal proliferation, Southern blot analysis of the frozen tissue revealed rearrangements in the heavy and light chains of the immunoglobulin gene, with no T-cell receptor gene rearrangement suggestive of a lymphoproliferative disorder. These findings indicate that the identification of gene rearrangement may be utilized to distinguish between true lymphoma and pseudolymphoma.     

Preliminary evaluation of a technique for inhibiting intimal hyperplasia: Implantation of a resorbable luminal collagen membrane

Pharmacologic control of intimai hyperplasia has been attempted through oral and intravenous administration of smooth muscle cell inhibitors. We report a more direct method of altering arterial healing using a novel bioresorbable membrane that can be applied to the lumen of an artery or anastomosis following endarterectomy or vascular reconstruction. Following a standard balloon injury, the infrarenal aortas of 3 kg female New Zealand white rabbits were opened and a thin membrane composed of collagen/chondroitin 6-sulfate copolymer was sutured to the posterior wall of each artery. Animals were killed at intervals of up to 3 months. All arteries remained patent. By 24 hours the membrane had become infiltrated with fibrin and red blood cells. An inflammatory response ensued and by 8 days the membrane was filled with mononuclear cells. At 3 months only a small remnant of the membrane remained. Intimal hyperplasia developed throughout the injured aorta. However, the hyperplastic response beneath the membrane was no greater than that observed in the adjacent injured aorta. A bioresorbable membrane can be sutured into the lumen of a small-diameter vessel without inducing thrombosis and without locally increasing intimal hyperplasia. A prosthesis of this type might be used to deliver inhibitors of smooth muscle cell proliferation and migration to the injured arterial wall.Supported by grants from the Whitaker Health Sciences Foundation and the Beth Israel Surgical Foundation.     

Evaluation of soft tissue sarcomas response to preoperative treatment: Assessment by angiography,thallium scintigraphy,and dynamic MRI

Background Assessment of the response of soft tissue sarcomas to preoperative treatment is of significant clinical importance. However, there are few reports concerning the accuracy of each imaging technique in assessing the response of soft tissue sarcomas to preoperative treatment. Methods The responses of 15 soft tissue sarcomas to preoperative treatment by digital subtraction angiography, thallium scintigraphy, and dynamic magnetic resonance imaging (MRI) were compared with histologic evaluation of the resected specimens. Tumors with at least 90% histologic necrosis were considered to be effectively treated. Results The accuracy of each assessment technique was 58.3% for digital subtraction angiography, 80% for thallium scintigraphy, and 77.8% for dynamic MRI. Both the differences in slope before and after treatment and the posttreatment slope values of dynamic MRI correlated with the histologic responses. Conclusion Thallium scintigraphy and dynamic MRI showed sufficient value in the assessment of soft tissue sarcomas responses to preoperative treatment. Dynamic MRI had major advantages in its quantitative and spatial resolutions.     

The uncinate process: A histological and morphological study

The uncinate process (UP) has become a familiar anatomical landmark to otolaryngologists due to the increasing popularity of functional endoscopic sinus surgery (FESS) in recent years. This study examines the histological and morphological features of UPs removed from a group of patients undergoing FESS operations for chronic sinusitis. The structure of the UP by light microscopy (LM) is reported. A relatively high proportion of goblet cells and seromucous glands was noted. Scanning electron microscopy (SEM) identified four surface cell types on the UP. Furthermore, four categories of surface morphology were noted. The most common appearance was of predominantly ciliated cells. A nonciliated surface ultrastructure is associated with a longer history of sinonasal symptoms and a higher incidence of surgical intervention.     

Endoscopically managed superficial carcinoma overlying esophageal lipoma

The occurrence of superficial carcinoma over a benign tumor of the esophagus is considered to be rare. Only a few reports have been reported and all of them were treated surgically. We now report one case of superficial carcinoma overlying an esophageal lipoma that was successfully resected endoscopically. The patient was a 61‐year‐old man who had no symptoms. A submucosal tumor was found at the thoracic esophagus by upper gastrointestinal endoscopy. The top of the tumor was slightly depressed with mild redness and its surface was irregular. This depressed lesion was not stained by iodine. Histological examination of endoscopic biopsy revealed squamous cell carcinoma. To completely remove this tumor in a single fragment, we used an insulation‐tipped electrosurgical knife. An en bloc resection of the tumor was completed without complications.