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Results for “recurrence timing”

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PubMed1995

Brain metastases in epithelial ovarian carcinoma.

Central nervous system metastases from epithelial ovarian carcinoma are uncommon. A retrospective study was undertaken to see if there was a difference in brain metastases from ovarian cancer in our patient population as compared to the literature. A retrospective study of all patients diagnosed with brain metastases from epithelial ovarian carcinoma at two institutions was performed. All patients were analyzed for stage, grade, type of chemotherapy, sites of recurrence, time to relapse, and survival after relapse. The results were compared to a compilation of reported cases from the literature. Sixteen patients with central nervous system metastases of 479 patients treated for ovarian carcinoma between January 1, 1979 and December 31, 1992 were identified. All 16 patients were diagnosed with serous cystadenocarcinoma, and all were either stage III or IV on presentation. Fifteen of the 16 patients had grade 2 or 3 disease. Histologic grade, at the time of diagnosis, did not influence survival after central nervous system recurrence; however, stage at original diagnosis did influence survival after brain metastases (P < 0.001). Eight of 11 patients undergoing second-look laparotomy had no evidence of disease. The most common presenting symptom of central nervous system disease was a slowly worsening headache of several weeks duration. The median time from original diagnosis to diagnosis of central nervous system disease was 19 months with a median survival after diagnosis of central nervous system disease of 3 months. The incidence of brain metastases in patients with epithelial ovarian carcinoma in our institutions was 3.3%. In conclusion, our incidence of brain metastases of 3.3% was not statistically significant from other reported rates. Patients who underwent radiation therapy with either craniotomy or chemotherapy for their brain metastases fared better than those who received radiation alone.

Adult↗
PubMed2001

Modeling genetic regulatory dynamics in neural development.

We model genetic regulatory networks in the framework of continuous-time recurrent networks. The network parameters are determined from gene expression level time series data using genetic algorithms. We have applied the method to expression data from the development of rat central nervous system, where the active genes cluster into four groups, within which the temporal expression patterns are similar. The data permit us to identify approximately the interactions between these groups of genes. We find that generally a single time series is of limited value in determining the interactions in the network, but multiple time series collected in related tissues or under treatment with different drugs can fix their values much more precisely.

Algorithms↗
PubMed2001

Analyses of transient chaotic time series.

We address the calculation of correlation dimension, the estimation of Lyapunov exponents, and the detection of unstable periodic orbits, from transient chaotic time series. Theoretical arguments and numerical experiments show that the Grassberger-Procaccia algorithm can be used to estimate the dimension of an underlying chaotic saddle from an ensemble of chaotic transients. We also demonstrate that Lyapunov exponents can be estimated by computing the rates of separation of neighboring phase-space states constructed from each transient time series in an ensemble. Numerical experiments utilizing the statistics of recurrence times demonstrate that unstable periodic orbits of low periods can be extracted even when noise is present. In addition, we test the scaling law for the probability of finding periodic orbits. The scaling law implies that unstable periodic orbits of high period are unlikely to be detected from transient chaotic time series.

Journal Article↗
PubMed2005

Time-decreasing hazard and increasing time until the next earthquake.

The existence of a slowly always decreasing probability density for the recurrence times of earthquakes in the stationary case implies that the occurrence of an event at a given instant becomes more unlikely as time since the previous event increases. Consequently, the expected waiting time to the next earthquake increases with the elapsed time, that is, the event moves away fast to the future. We have found direct empirical evidence of this counterintuitive behavior in two worldwide catalogs as well as in diverse regional catalogs. Universal scaling functions describe the phenomenon well.

Journal Article↗
PubMed1985

Recurrent Spitz's nevi. A clinicopathologic investigation.

Spitz's nevi recur uncommonly following initial removal. A clinicopathologic investigation was performed on 16 such cases. The initial nevi in almost all cases extended to the margins of the sections. Otherwise, these lesions showed no unusual clinical or histologic features. The average recurrence time was 13 months, with a range from 2 months to 3 years. The recurrent lesions occasionally were mistaken clinically for keloids. Histologically, recurrent lesions were predominantly intradermal. Nests, fascicles, and individual spindle and/or epithelioid cells extended to the deep reticular dermis and occasionally into the subcutaneous fat. The surrounding stroma was densely fibrotic. Recurrent Spitz's nevi are different clinically and histologically from recurrent ordinary melanocytic nevi. They also often differ histologically and clinically from primary Spitz's nevi. Recurrent Spitz's nevi are similar histologically to the desmoplastic type of Spitz's nevus.

Adolescent↗
PubMed2005

The use of aromatase inhibitors in adjuvant therapy for early breast cancer.

Clinical evidence supporting the use of aromatase inhibitors (AIs) in adjuvant therapy for hormone-sensitive early breast cancer (EBC) has grown rapidly over the past few years and is reviewed in this article. The results of two studies-the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial and the Breast International Group (BIG) 1-98 trial-support the use of AIs as primary adjuvant therapy for EBC, with significantly prolonged disease-free survival, time to recurrence, and time to distant recurrence for both anastrozole and letrozole over tamoxifen. Furthermore, anastrozole has an established beneficial risk:benefit ratio compared with tamoxifen with mature data over the full 5-year recommended treatment period. For women who have already received 2-3 years of tamoxifen, switching studies with anastrozole [the Italian Tamoxifen Anastrozole (ITA) trial and the Austrian Breast and Colorectal Cancer Study Group (ABCSG) 8/Arimidex-Nolvadex (ARNO 95) trial] and exemestane [the Intergroup Exemestane Study (IES)] have also shown that 5 years of primary adjuvant tamoxifen therapy is not optimal and that switching to an AI should be considered. Finally, for those women who have completed 5 years of tamoxifen, based on the results of the MA 17 trial, extended adjuvant treatment with letrozole should be considered. Although no sequencing data are available yet, current evidence suggests that an AI should be the adjuvant treatment of choice over tamoxifen, and anastrozole is the only AI with mature adjuvant data to date.

Aromatase Inhibitors↗
PubMedDate not supplied

Follow-up and recurrence of T1 colorectal cancer.

This study was performed to clarify the clinical and pathological characteristics of T1 colorectal cancer. From 1987 to 2003, a total of 223 patients with T1 colorectal cancer were treated at our institute. Disease recurrence occurred in eight (3%) of these cases. The original sites of cancer were the ascending colon (n = 1), sigmoid colon (n = 2), and rectum (n = 5). We performed three local resections per anus and five bowel resections with lymph node dissection. In cases showing recurrence after resection, lymph node metastasis was observed more frequently (four of five cases; 80%) compared with the cases showing no recurrence (11%). The average recurrence time was <36 months in seven of the eight cases (88%). Local recurrence occurred in five of the eight cases (63%). We conclude that careful follow-up is necessary in cases of T1 colorectal cancer in the first 3 years after treatment.

Aged↗
PubMed1988

First-episode, recurrent, and asymptomatic herpes simplex infections.

Genital herpes simplex virus infections should be classified into first-episode and recurrent infections. First-episode infections include true primary infections in patients with seronegative results who have never been infected with any type of herpes and nonprimary first-episode infections in patients who have been infected before and have serum antibody and humoral immunity, an example being genital infection with type 2 in adolescence after orolabial infection with type 1 in childhood. First-episode infections show more extensive disease, more systemic symptoms, and greater viral shedding than do recurrent infections. Ten percent to 15% of patients with first-episode primary genital herpes have oropharyngeal infections with the same virus strain. Herpesvirus can be isolated from the urethra in about 30% of male patients with first-episode infections. In recurrent vulvar herpes, virus can be isolated from the cervix in 10% to 15% of patients. Many genital lesions that clinically suggest something else turn out to be herpes; herpes may be diagnosed 5% of the time clinically but cultures are positive 14% of the time. Primary genital herpes type 2 infections recur about 95% of the time whereas type 1 infections recur about 50% of the time. Recurrences are highly unpredictable from patient to patient and time to time. The role of asymptomatic shedding in the spread of herpes is a major area for future study. Antiviral treatment is probably going to change the epidemiology of herpetic infections very little.

Adolescent↗
PubMed2001

Totally extraperitoneal endoscopic repair of recurrent inguinal hernia.

BACKGROUND: Conventional repair of recurrent inguinal hernia is associated with a re-recurrence rate as high as 35 per cent. Endoscopic mesh repair has promising results regarding both recurrence and complication rates. METHODS: In a retrospective review, the results of endoscopic totally extraperitoneal repair were evaluated in 104 patients with 108 recurrent hernias. Follow-up was at least 1 year. Type of recurrence, time of occurrence after previous repair, duration of surgery, complications, duration of hospital stay and number of re-recurrences were evaluated. RESULTS: Follow-up ranged from 12 to 29 (mean 16) months. Forty-three recurrences were direct, 41 indirect and 15 combined; one was a femoral hernia. Median time to previous operation was 36 months (range 8 days to 42 years). Median duration of surgery was 63 (range 25--160) min. While there were no complications during operation, 12 patients (12 per cent) had a postoperative complication. Two direct re-recurrences (2 per cent) occurred as a result of inadequate positioning of the prosthetic mesh. CONCLUSION: The endoscopic totally extraperitoneal technique is safe and effective for the repair of recurrent inguinal hernia.

Adult↗
PubMed2002

Impact of myocardial ischemia and reperfusion on ventricular defibrillation patterns, energy requirements, and detection of recovery.

BACKGROUND: Shocks that have defibrillated spontaneous ventricular fibrillation (VF) during acute ischemia or reperfusion may seem to have failed if VF recurs before the ECG amplifier recovers after shock. This could explain why the defibrillation threshold (DFT) for spontaneous VF appears markedly higher than for electrically induced VF. METHODS AND RESULTS: The DFT for electrically induced VF (E-DFT) was determined in 15 pigs before ischemia, followed by left anterior ascending or left circumflex artery occlusion. VF was electrically induced 20 minutes after occlusion, followed 5 minutes later by reperfusion. Whether spontaneous or electrically induced, VF during occlusion or reperfusion was treated with up to 3 shocks at 1.5xE-DFT. If all 3 shocks failed, shock strength was increased. Thirty minutes after reperfusion, the other artery was occluded and the protocol was repeated. Defibrillation was considered successful if postshock sinus/idioventricular rhythm was present for > or = 30 seconds. VF recurring within 30 seconds after the shock was considered immediate or delayed if the first postshock activation complex in a rapidly restored ECG recording was VF or sinus/idioventricular rhythm, respectively. Defibrillation efficacy at 1.5xE-DFT was significantly higher for electrically induced ischemic VF (76%) than for spontaneous VF (31%). The incidence of delayed recurrence after electrically induced nonischemic (3%) or ischemic (20%) VF was significantly lower than after spontaneous VF (75%). Mean VF recurrence time after spontaneous VF was 4.6+/-5.3 seconds. CONCLUSIONS: Spontaneous VF can be halted by a shock but then quickly restart before a standard ECG amplifier has recovered from postshock saturation, making it appear that the shock failed.

Animals↗
PubMed1989

Lower pole divergence of kidney: a new surgical technique to prevent recurrent renal calculus.

Gravity and natural position of the kidney have emerged as important factors in the nucleation, growth and postoperative recurrences of renal stones. A new operation technique is described to alter the position of the kidney, hence countering all obstacles to urinary flow. Recurrence of stones after the new operation (8.1%) were compared with controls (15.0%). Recurrence rates revealed from history data at two years (15-28%) and life-time recurrences deduced therefrom (25-80% or more) were used for comparison. Postnephropexy figures were 5.97% and 10-25% respectively. It strengthened our belief that to check inevitable postoperative recurrences, this new operation should be applied whenever open surgery is performed for nephrolithiasis.

Adult↗
PubMed1995

Normobaric oxygen as a sensitizer in radiotherapy for advanced head and neck cancer.

The aim of this study was to evaluate radiosensitizing effect of normobaric oxygen breathing in radiotherapy for advanced head and neck cancers. Forty seven patients with advanced squamous cell carcinomas of the head and neck (7% in Stage III and 93% in Stage IV) were entered in the study. Breathing the pure, normobaric oxygen was given for 15-20 min in the treatment room. Irradiation started immediately after oxygen breathing. Conventional, megavoltage radiotherapy to the total doses in the range of 46-67.5 Gy was used. The control group was 46 patients with the same diagnosis and stage treated by radiotherapy alone. Locoregional tumor control was 36% in the study group compared to 15% in the control (p < 0.05). Mean survival time was 15.8 and 11.8 months, and 3-year survival was 19% and 2%, respectively (p < 0.05). Survival depended on total tumor dose and total nodal dose. No significant influence of the tumor location on local control and importance of the size of dose per fraction and overall treatment time were found. The most common failure in both groups was persistent tumor. Mean recurrence time was 5 months in the study group and 8 months in the control. Present results suggest that the use of normobaric oxygen breathing prior to irradiation could increase effectiveness of conventional radiotherapy for advanced squamous cell carcinomas of head and neck.

Carcinoma, Squamous Cell↗
PubMed1995

Progressive type of focal nodular hyperplasia characterized by multiple tumors and recurrence.

Focal nodular hyperplasia (FNH) is usually a stable lesion that does not enlarge when studied for long periods of time; recurrence after resection has not been reported. We present a patient with a solitary FNH lesion that enlarged, was resected, and then recurred. A second resection was performed because of abdominal pain and disclosed multiple lesions, two of which were acutely infarcted. Thirty-two months later there was ultrasound evidence of further recurrence. Histology of the lesions showed the usual appearance of FNH with ducts and ductules in the central stalk regions but also some areas with minimal ductular differentiation and scanty connective tissue. Because of the clinical and histological appearance, the lesions in this patient were distinct from the usual type of FNH and merit the name "focal nodular hyperplasia, progressive type."

Adult↗
PubMedDate not supplied

Influence of alcohol abuse on recurrence after curative resection of hepatocellular carcinoma.

BACKGROUND/AIM: We studied the influence of alcohol abuse (ethanol intake > 80 gm/day for > 5 yr.) on recurrence in 81 patients with hepatocellular carcinoma who had undergone curative hepatic resection. Twenty-nine patients were positive for alcohol abuse [AA(+)] and 52 were not [AA(-)]. RESULTS: Recurrence of carcinoma within 2 and 27 postoperative months was observed in 45 (55.6%) of the 81 patients. The median disease-recurrence time was 12.0 mo in the AA(+) group and 24.1 mo in the AA(-) group (p<0.01). The patterns of recurrence were classified into the following 4 types: single-nodular type (intrahepatic single nodule); multi-nodular type (intrahepatic multiple nodules); whole liver type (diffuse recurrence over the whole remnant liver); and extrahepatic type (extrahepatic recurrence alone). Five (29.4%) of the 17 patients with recurrence in the AA(+) group demonstrated the whole liver type, compared with only 2(7.1%) of the 28 patients in the AA(-) group (p<0.05). CONCLUSION: Patients with alcohol abuse should be followed up particularly closely, even if they have received curative surgery, since alcohol abuse is strongly related to postoperative recurrence.

Alcoholism↗
PubMed1999

Embedding recurrent neural networks into predator-prey models.

We study changes of coordinates that allow the embedding of ordinary differential equations describing continuous-time recurrent neural networks into differential equations describing predator-prey models-also called Lotka-Volterra systems. We transform the equations for the neural network first into quasi-monomial form (Brenig, L. (1988). Complete factorization and analytic solutions of generalized Lotka-Volterra equations. Physics Letters A, 133(7-8), 378-382), where we express the vector field of the dynamical system as a linear combination of products of powers of the variables. In practice, this transformation is possible only if the activation function is the hyperbolic tangent or the logistic sigmoid. From this quasi-monomial form, we can directly transform the system further into Lotka-Volterra equations. The resulting Lotka-Volterra system is of higher dimension than the original system, but the behavior of its first variables is equivalent to the behavior of the original neural network. We expect that this transformation will permit the application of existing techniques for the analysis of Lotka-Volterra systems to recurrent neural networks. Furthermore, our results show that Lotka-Volterra systems are universal approximators of dynamical systems, just as are continuous-time neural networks.

Journal Article↗
PubMed2000

Coarse-grained reverse engineering of genetic regulatory networks.

We have modeled genetic regulatory networks in the framework of continuous-time recurrent neural networks. A method for determining the parameters of such networks, given expression level time series data, is introduced and evaluated using artificial data. The method is also applied to a set of actual expression data from the development of rat central nervous system.

Algorithms↗
PubMed1998

Study on the causes of local recurrence of rectal cancer after curative resection:analysis of 213 cases.

AIM:To study the local recurrent rate and the causes of rectal cancer after surgery.METHODS:The clinicopathological data of 213 rectal cancer patients and the follow-up information were analyzed. The overall recurrent rate and the recurrent rates from different surgical appreaches were calculated. The main causes of recurrence were investigated.RESULTS:Among the 213 cases, 73 (34.27%) had local recurrence. The recurrent time ranged from 3 months to 62 months after the first operation. Most of the recurrence (65/73, 89.04%) occurred within 3 years after operation.CONCLUSION:Local recurrence had no significant correlation with surgical methods or pathological types, but closely related to Dukes' stages, location of primary tumors and the length of the distal rectum resected. Early resection and a wide tumor free resection margin are key factors to prevent local recurrence.

Journal Article↗
PubMed2001

[Recurrent pterygium: removal and plastic procedure with the use of amniotic membrane: a case history].

AIM: Pterygium is the primitive degenerative and hyperplastic pathology of the conjunctiva. The origin and nature of the primary pterygium lesion is still not fully understood. Surgery is used as a treatment for primary and recurrent pterygium. The surgical techniques applied range from simple surgical removal to complex procedures comprising the treatment of the optical zone and the repair of the conjunctiva. Conjunctival reconstruction may be carried out with free graft of the amniotic membrane. MATERIAL AND METHODS: The paper presents a case history of a patient with 18-fold pterygium removal during the period of last 6 years. The mean recurrence time during the last 2 years ranged between 2-3 months. The pterygium was again removed, and conjunctivoplasty was performed using amniotic membrane. The paper presents the steps of the surgery and the patient's postoperative course. The clinical state and subjective symptoms improved in the postoperative period. The follow-up time was 6 months. RESULTS: The amniotic membrane graft for pterygium surgery is useful for recurrent pterygium in achieving a lower recurrence rate, quicker rehabilitation and agreeable cosmetic result.

Biological Dressings↗