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Biomedical subjects

G Rosenthal

Publications and source records attributed to G Rosenthal.

At least 19 recordsLinked to original sources
PubMed2002

Overexpression of p53 tumor suppressor gene in pterygia.

PURPOSE: To assess p53 gene expression in pterygia with and without recurrence. The pathogenesis of pterygium has not yet been determined. The most widely recognized etiologic factor is ultraviolet radiation, which leads to degeneration of the conjunctiva. However, pterygium was recently found to have several tumor-like characteristics. The p53 gene is a common marker for neoplasia, and is known to control cell cycle, cell differentiation and apoptosis. In this study we examined the expression of the p53 gene in primary pterygia with and without recurrence, searching for the pathogenesis of this very common lesion and for a prognostic factor for recurrence. METHODS: Immunohistochemical staining using a monoclonal antibody to human p53 (DO-7) was performed on 13 consecutive patients with primary pterygia, four pterygia without recurrence and nine pterygia which recurred during a 12-month follow-up. As a control we used two specimens of normal conjunctiva. RESULTS: Seven of the 13 pterygia specimens (54%) were positive for abnormal p53 expression. There was no difference between the groups with and without recurrence. Two out of four pterygia (50%) without recurrence and five out of nine (55.5%) pterygia with recurrence were positive. No pathological staining was observed in the control specimens. CONCLUSIONS: In this study, abnormal p53 expression was found in pterygial epithelium, suggesting that pterygium could be a result of uncontrolled cell proliferation, and not as a degenerative lesion. There seems to be no connection between abnormal p53 expression and recurrence.

Antibodies, Monoclonal↗
PubMed2001

Protein kinase Calpha and protein kinase Cdelta play opposite roles in the proliferation and apoptosis of glioma cells.

Protein kinase C (PKC) has been implicated in the proliferation and apoptosis of glial tumors, but the role of specific PKC isoforms remains unresolved. Comparing brain tumors differing in degree of malignancy, we found that malignant gliomas expressed higher levels of PKCalpha and lower levels of PKCdelta as compared with low-grade astrocytomas. Consistent with a mechanistic role for these differences, overexpression of PKCalpha in the human U87 glioma cell line resulted in enhanced cell proliferation and decreased glial fibrillary acidic protein (GFAP) expression as compared with controls. Reciprocally, overexpression of PKCdelta inhibited cell proliferation and enhanced GFAP expression. Using PKC chimeras, we found that the regulatory domains of PKCalpha and PKCdelta mediated their effects on cell proliferation and GFAP expression. PKCalpha and delta have been implicated as potential signaling molecules in apoptosis. Therefore, we examined the role of these isoforms in the resistance of glioma cells to apoptotic stimuli. In U87 cells, manipulation of PKCalpha levels had little effect on apoptosis in response to etoposide. In contrast, overexpression of PKCdelta rendered the U87 cells more sensitive to the apoptotic effect of etoposide, and PKCdelta was cleaved in these cells by a caspase-dependent process. Furthermore, the glioma cell line U373, which expresses endogenous PKCdelta, underwent apoptosis in response to etoposide, and the apoptotic response was blocked by the PKCdelta inhibitor rottlerin. Our results suggest that PKCalpha and PKCdelta play opposite roles in the proliferation and apoptosis of glioma cells.

Antineoplastic Agents, Phytogenic↗
PubMed2001

Effect of the total motile sperm count on the efficacy and cost-effectiveness of intrauterine insemination and in vitro fertilization.

OBJECTIVE: To determine prognostic factors for achieving a pregnancy with intrauterine insemination (IUI) and IVF. To compare the effectiveness and cost-effectiveness of IUI and IVF based on semen analysis results. DESIGN: Retrospective cohort study. SETTING: Academic university hospital-based infertility center. PATIENT(S): One thousand thirty-nine infertile couples undergoing 3,479 IUI cycles. Four hundred twenty-four infertile couples undergoing 551 IVF cycles. INTERVENTION(S): IUI and IVF treatment. MAIN OUTCOME MEASURE(S): Multiple logistic regression analysis was used to assess the significance of prognostic factors including a woman's age, gravidity, duration of infertility, diagnoses, use of ovulation induction, and sperm parameters for predicting the outcomes of clinical pregnancy and live birth rate after the first cycle of IUI and IVF. The relative effectiveness and cost-effectiveness of these treatments were then determined based on sperm count results. RESULT(S): Female age, gravidity, and use of ovulation induction were all independent factors in predicting pregnancy after IUI. The average total motile sperm count in the ejaculate was also an important factor, with a threshold value of 10 million. For IVF, only female age was an important predictor for both clinical and ongoing pregnancy. When the average total motile sperm count was under 10 million, IVF with ICSI was more cost-effective than IUI in our clinic. CONCLUSION(S): An average total motile sperm count of 10 million may be a useful threshold value for decisions about treating a couple with IUI or IVF.

Adult↗
PubMed2001

Toxic effects of subconjunctival 5-fluorouracil and mitomycin C on ciliary body of rats.

PURPOSE: The effects of subconjunctival injection of mitomycin C and different concentrations of 5-fluorouracil on the epithelium of the ciliary body of twenty Sprague Dawley SD rats was studied. METHODS: Twenty rats were divided into four treatment groups. The first three groups received 0.2 ml of 5, 10, and 30 mg of 5-fluorouracil subconjunctivally respectively, and the fourth group 0.2 ml of 0.4 mg/ml mitomycin C subconjunctivally. The right eye received 0.2 ml of the antimetabolite, while the left eye was injected with 0.2 ml of saline subconjunctivally, as a control. The eyes were examined histologically, in a masked fashion, by light and by transmission electron microscopy. In each treatment group, two eyes were examined after one week, and three eyes were examined one month after the subconjunctival injection. RESULTS: Electron microscopy revealed toxic effects in the epithelium of the ciliary body of all treatment groups. The 5-fluorouracil group revealed focal mitochondrial edema, enlargement of intercellular spaces, and dilatation of intracellular spaces. The mitomycin C group showed pyknotic nuclei, enlargement of intercellular spaces, and irregular flattened epithelial cells. The severity of changes correlated with concentration and length of exposure. No pathology was found by light microscopy in all groups. CONCLUSIONS: This study demonstrates that subconjunctival antimetabolites mitomycin C and 5-fluorouracil can penetrate the sclera and exert toxic effects on the epithelium of the ciliary body, even in low doses. These changes were only apparent by electron microscopy and were still present one month after the injection. These findings may contribute to the theory that the application of antimetabolites during or after surgery has a direct effect on the epithelium of the ciliary body, besides its known effect on the conjunctiva. Further studies are needed to evaluate its effect on intraocular pressure.

Animals↗
PubMed2000

Technique and early results of outpatient laparoscopic mesh onlay repair of ventral hernias.

BACKGROUND: This report describes the technique and early results of a simple outpatient laparoscopic ventral hernia repair. METHODS: Data were gathered prospectively for all laparoscopic ventral hernia repairs from January 1996 to December 1997 at a 228-bed hospital. Prolene mesh was stapled to the peritoneal surface of the abdominal wall, leaving sac in situ and mesh uncovered. Patients were seen by the operating surgeon within 2 months, and by an impartial surgeon (J.S.) after 3 to 14 months (average, 7 months; median, 6 months). RESULTS: Repairs involved 44 hernias with orifice sizes 2 to 20 cm in diameter, and an average area of 20 cm(2). Of these 44 hernias, 36 were postoperative and 8 primary. Furthermore, 20% were recurrent hernias. There were four conversions. The outpatient rate was 98%, with one readmission for ileus. The early recurrence rate was 5%. CONCLUSIONS: Laparoscopic mesh onlay repair is a safe, easy, and effective procedure with minimal discomfort and a low early recurrence rate that can be performed safely on an outpatient basis.

Adult↗
PubMed1999

360 Degrees of epibulbar granulation tissue thirteen years after silicone circle buckle operation.

To demonstrate a granulomatous reaction to silicone buckel thirteen years after retinal detachment surgery. We report on a 71-year-old man who developed a 360 degrees of epibulbar granulation tissue due to silicone circle buckel. The granulation tissue was demonstrated by a computer tomography and histologically. A granulomatous reaction to silicone circle buckel can be found many years from the first operation. Biopsy is always necessary to establish a definitive diagnosis. Treatment of 360 degrees of epibulbar granulation tissue causing ocular dysfunction is by surgical excision.

Aged↗
PubMed1999

Factors contributing to laparoscopic failure during the learning curve for laparoscopic Nissen fundoplication in a community hospital.

This study was done to determine the factors contributing to laparoscopic failure (conversion to open surgery or early reoperation) during the learning curve for laparoscopic Nissen fundoplication in a 228-bed nonteaching community hospital. Data were gathered prospectively for the first 100 consecutive patients booked for elective laparoscopic Nissen fundoplication by the four general surgeons at the hospital. All complications were recorded contemporaneously, and particular note was taken of the factors surrounding conversion to open surgery and reoperation within 100 days of surgery. There were no deaths. The conversion rate was 20% and the early reoperation rate 6%. There were two late recurrences. The average operative time was 117 minutes and the average length of stay 1.8 days; 37 operations were performed on outpatients. The laparoscopic failure rate was 26% (18/68) during a surgeon's first 20 operations and 11% (3/28) thereafter (P < 0.09); the corresponding conversion rates were 22% and 4% (P < 0.05). During a surgeon's first 20 operations, the laparoscopic failure rate rose from 21% (12/57) to 55% (6/11) (P < 0.04) if a second surgeon did not assist. After 20 operations, this difference lost its significance. Intrathoracic herniation of the stomach was found preoperatively in 11 (44%) of 25 operations followed by laparoscopic failure and (8%) 6 of 75 without (P < 0.0002). Laparoscopic failure had no correlation with patient age, sex, ASA classification, duration of symptoms, or referring physician's specialty. The individual learning curve for laparoscopic Nissen fundoplication requires about 20 operations to surmount. Factors leading to laparoscopic failure during the learning curve are the surgeon's inexperience, absence of experienced help, and the presence of intrathoracic herniation.

Adult↗
PubMed1999

Acetaminophen (paracetamol) levels in human tears.

This study was designed to measure acetaminophen (paracetamol) levels in tears, and to compare it to serum levels. Paracetamol levels were measured in 20 paired tears and serum samples from 10 healthy volunteers, 1 and 2 hours after ingesting 1.5 g paracetamol. Tears were collected using glass microcapillary tubes while stimulating the conjunctiva with a small sponge placed in the lower fornix. Blood samples were taken simultaneously. The samples were analyzed for paracetamol levels using homogeneous enzyme immunoassay. Tears and serum paracetamol levels 1 hour after ingestion were 16.3 microg/mL +/- 7.2 (mean +/- SD), and 21.4 microg/mL +/- 7.7 (mean +/- SD) respectively. Tears and serum levels 2 hours after ingestion were 14.4 microg/mL +/- 7.8 (mean +/- SD), and 17 microg/mL +/- 7.6 (mean +/- SD) respectively. Tears and serum paracetamol levels of all the 20 paired samples (1 h and 2 h after ingestion) were 15.35 microg/mL +/- 7.4, and 19.25 microg/mL +/- 7.8, respectively (mean +/- SD). There was a strong and highly significant correlation between paracetamol levels in serum and in tears 1 and 2 hours after ingestion (r = 0.8, p = 0.005, r = 0.85, p = 0.002 respectively). Mean +/- SD ratio of tears/serum paracetamol levels 1 hour and 2 hours after ingestion were 0.77 +/- 0.21 and 0.81 +/- 0.25 respectively. Delta tears (difference in mean levels at 1 and 2 hours) paracetamol levels is significantly correlated with delta serum levels (r = 0.7, p = 0.025). A reliable, convenient, and feasible noninvasive method is described for measuring paracetamol in tears. There is no information in the literature about tears paracetamol secretion, and little information of tears drugs concentration.

Acetaminophen↗
PubMed1998

Autologous platelet treatment for optic disc pit associated with persistent macular detachment.

PURPOSE: To determine the effectiveness of autologous platelets in repair of optic disc pit associated with persistent macular detachment. PATIENT: We report on a 44-year-old woman with optic disc pit associated with persistent macular detachment. The patient underwent an uneventful pars plana vitrectomy with autologous platelets injected over the optic disc pit. Good anatomical and functional results were obtained. CONCLUSION: This surgical approach may be a valuable adjunct to the surgical management of optic disc pit associated with persistent macular detachment.

Adult↗
PubMed1998

Failure of sorivudine therapy in progressive outer retinal necrosis caused by varicella zoster virus.

BACKGROUND: We report on the case of a 23-year-old female who presented with ocular signs of progressive outer retinal necrosis (PORN) syndrome and who failed to respond to acyclovir, ganciclovir, foscarnet and oral sorivudine. METHODS: The patient was treated with the antiviral drugs acyclovir, ganciclovir, foscarnet and oral sorivudine. RESULTS: The patient failed to respond to a combination of antiviral drugs. Unfortunately, progression of the retintis occurred, which led to blindness. CONCLUSION: Despite new drugs, the prognosis of PORN is poor and recurrence is common.

AIDS-Related Opportunistic Infections↗