Effect of suramin on differentiation of human stomach cancer cell lines.

This study was designed to demonstrate that differentiation of stomach cancer cells can be modified by microenvironmental change and to look for a method inducing or promoting tumor cell differentiation. To evaluate the biomorphological characterization of tumor cell differentiation in suramin-containing in vitro culture of human stomach cancer cell lines, inverted phase-contrast microscopic examination, analysis of growth curves and BrdU-positive S-phase fraction, immunocytochemical study, radioimmunoassay for CEA, transmission electron microscopic examination, DNA flow cytometry, and heterotransplantation in SCID mice were performed. Suramin inhibited tumor cell growth. Development of intracytoplasmic lumina and intercellular lumina was noted in suramin-containing culture with formation of numerous microvilli and frequent desmosomes. The amount of CEA released by a cell was increased in suramin-containing culture. Suramin inhibited heterotransplantation, and a transplant from suramin-containing culture revealed a much higher degree of differentiation than that from suramin-absent culture. Suramin induced no change in DNA ploidy pattern. Elimination of suramin from the culture medium did not reverse the tumor cell differentiation. Each stomach cancer cell line showed a different degree of responsiveness to suramin. In conclusion, this study shows that suramin inhibits growth of SNU-5 and SNU-16 cells and that suramin induces differentiation of SNU-16 cells.     

The sequence of development of intestinal tissue injury after strangulation ischemia and reperfusion

Tissue injury at reperfusion has been reported after partial ischemia. However, previous attempts to demonstrate a component of injury caused by reperfusion after total ischemia have failed. This study was performed to evaluate the hypothesis that in such situations the extent of the tissue injury caused by ischemia itself prevented detection of a reperfusion component. Rats were subjected to near-total intestinal ischemia by means of a hydrostatic pressure clamp that produced preferential venous occlusion (strangulation) for periods from 1 to 90 minutes. Tissue injury was evaluated microscopically by a blinded examiner. Ischemic periods of 20 minutes or less did not induce detectable tissue injury. Longer durations of ischemia caused villous injury: the longer the period of ischemia, the more extensive the tissue injury. However, there was no exacerbation of injury seen after reperfusion, regardless of the duration of ischemia. In a separate series of rats, total arterial occlusion was employed without concomitant venous congestion. Such isolation arterial occlusion of 40 to 60 minutes' duration was followed by a statistically significant exacerbation of tissue injury at reperfusion. Thus total intestinal ischemia may be followed by reperfusion injury if there is no concomitant congestion and if ischemic injury is not too extensive.     

Resorption rate and biocompatibility characteristics of two polyester ventilation tubes in a guinea pig model

OBJECTIVES: Determine the resorption rate and biocompatibility characteristics of 2 polyester ventilation tubes, and to determine whether soap and water exposure accelerates polyester tube degradation. STUDY DESIGN AND SETTING: 50/50 poly (D, L-lactide-co-glycolide; PLGA-50) and poly (L-lactide; PLA) polymers were placed into the tympanic membranes of Hartley pigmented guinea pigs. Integrity of the tubes was determined by weekly otoscopic examination. Biocompatibility was assessed by comparing auditory brainstem response (ABR) thresholds and by examining tympanic membrane changes following tube resorption. Shah minigrommet ventilation tubes were used as controls. In the second portion of this study, implanted PLGA-50 and PLA tubes were exposed weekly to a mixture of soap and water (1:5) until complete resorption was observed. Biocompatibility was assessed by periodic ABR testing and tympanic membrane examination. RESULTS: The PLA tubes remained in the tympanic membrane for a longer period (63.2 +/- 19.3 days) than the PLGA-50 (18.8 +/- 8.1 days). The tympanic membrane and resorbable tube interface demonstrated equivalent findings for auditory thresholds and tissue histopathology at the implant site compared to nonresorbable controls. The resorption behavior was not altered by exposure to soap and water. Tympanic membranes of all animals following tube degradation and soap water exposure were intact with minimal scarring and no signs of persistent foreign body response. The histological analysis showed that implantation of resorbable tubes was not accompanied by secondary infection with otorrhea through the tube, did not result in a permanent perforation or dislocation of the tube into the middle ear cavity, and was not followed by excess tympanosclerosis or localized or diffuse membrane atrophy. CONCLUSIONS AND SIGNIFICANCE: Resorbable polyester pressure equalization tubes demonstrate predictable resorption behavior and similar biocompatibility characteristics when compared with nonresorbable Shah minigrommet ventilation tubes. Exposure to soap water does not accelerate polyester tube degradation nor change the host tissue response during the indwelling period or after complete resorption. The data suggests that resorbable ventilation tubes are substantially equivalent to other FDA-approved tympanostomy devices with regard to safety and biocompatibility in the guinea pig model examined and may provide improved clinical performance by combining this approach with sustained release technology. EBM RATING: B-2.     

Simple measurement of spinal cord evoked potential: a valuable data source in the rat spinal cord injury model.

Measurement of spinal cord evoked potentials (SCEPs) is proposed as a means of predicting locomotion outcome in the rat spinal cord injury (SCI) model. Using 55 rats, three reproducible peak waves (waves I, II and III) were observed during stimulation at the C7 level with recording at the L1 epidural space. Hemisection at the T13 level showed three wave loss patterns: wave III loss only, loss of both wave II and III, and loss of all three waves. Defining an ideal SCI model as establishment of stable monoparesis or paraparesis, all animals in the wave II-III loss group showed favorable results. Histological data and electrophysiological properties allowed reasonable assumptions of wave origin: wave I from extrapyramidal tracts, wave II from the ventral corticospinal tract, and wave III from the dorsal corticospinal tract. Complete destruction of pyramidal tracts in both dorsal and ventral fibers was essential for long-term impairment of locomotion.     

Bilateral versus unilateral sudden sensorineural hearing loss.

OBJECTIVES: To analyze the clinical characteristics and treatment results between bilateral (bi-) and unilateral (uni-) sudden sensorineural hearing loss (SSNHL). STUDY DESIGN AND SETTING: A retrospective study. METHODS: Three hundred twenty-four patients with SSNHL were classified into two groups; simultaneous bi-SSNHL (n = 16) and uni-SSNHL (n = 308). We compared clinical characteristics, medical history, hearing level, and treatment results between the 2 groups. RESULTS: The incidence of bi-SSNHL was 4.9 percent of overall patients with SSNHL. Bi-SSNHL occurs more commonly in patients of older age, with preexisting diabetes mellitus, and lipid panel abnormalities compared with uni-SSNHL. Ten patients (62.5%) in the bi-SSNHL group showed hearing recovery in 1 or both ears compared with 56.5 percent of patients with uni-SSNHL. Only 12 (37.5%) of all 32 ears recovered in bi-SSNHL, which was significantly lower than in uni-SSNHL. CONCLUSION: Bi-SSNHL has a very low incidence and lower recovery rate than uni-SSNHL. Recognition of similarities and differences between bilateral and unilateral SSNHL can help in counseling and managing the patients.     

Hearing outcome of sudden sensorineural hearing loss: long-term follow-up.

OBJECTIVE: To evaluate the time-dependent progress and delayed improvement in patients who were treated with combination therapy including oral corticosteroid for idiopathic sudden sensorineural hearing loss. STUDY DESIGN AND SETTING: This retrospective study at a secondary referral and university-based center included 156 patients who were treated by 10-day course of admission therapy and followed for at least three months. RESULTS: Of 121 patients who recovered over three months of follow-up, 45.5% showed a delayed recovery after the end of 10-day course of therapy. Of these 55 patients, 78.2% recovered within one month, 5.5% recovered within one to two months, 12.7% recovered in two to three months, and 3.6% recovered later than three months after discharge. CONCLUSIONS: This study describes the long-term results for a three-month retrospective series of 156 patients diagnosed with idiopathic sudden sensorineural hearing loss, although this result should be further studied by additional research.     

Oral cancer induced in hamsters with herpes simplex infection and simulated snuff dipping

A number of epidemiologic studies indicate that snuff dipping is associated with an increased incidence of oral cancer in human beings. Since inactivated herpes simplex virus (HSV) has been shown to induce malignant changes in vitro and in vivo and is partially inactivated by snuff water extract, we examined the histopathologic changes of hamster buccal pouches after exposure to repeated HSV inoculation combined with long-term simulated snuff dipping. One hundred twenty-five Syrian hamsters were divided into seven groups, and the buccal pouches were inoculated with HSV-1, HSV-2, or culture medium. The mock and HSV inoculations were done once a month for 6 consecutive months. In an effort to determine the effect of snuff on the mock- or HSV-inoculated buccal pouches, a consistent amount of a commercially available snuff was placed into both the right and left pouches twice a day in half of the animals. At the end of the 6 months of simulated snuff dipping (4 weeks after the final mock or viral inoculation), the hamsters were killed and the buccal pouches were removed for the histopathologic evaluation. Neither simulated snuff dipping nor HSV infection alone induced neoplastic changes in hamster buccal pouches. However, HSV infection in combination with simulated snuff dipping resulted in epithelial dysplasia and invasive squamous cell carcinoma in more than 50% of the animals.     

Flavonoids from the leaves ofRhododendron brachycarpum

The flavonoids isolated from the leaves ofRhododendron brachycarpum, were identified as quercetin, avicularin, quercitrin and hyperin.     

Extensive Aberrant Mongolian Spot

A 9-month-old male infant had generalized diffuse blue-gray pigmentation over most of his body, sparing the scalp, face, neck, palms, soles, periumbilical area, genital area, and nipples. Within the lesion, there were several conspicuous macules of considerably darker hue. Histologic examination revealed numerous dermal melanocytes. By 16 months of age, the child's blue-gray pigmentation had decreased substantially.