Extent Of Regression Research Articles

Randomized Comparison of Progression of Atherosclerotic Plaques and Calcification of Coronary Artery in Atrial Fibrillation Patients Treated With Edoxaban Versus Warfarin (The REPRESENT-AF trial)

Although the adverse effects of long-term use of vitamin K oral anticoagulant (OAC), warfarin, on the coronary vasculature are well-established, it remains unknown whether nonvitamin K oral anticoagulants play a role in the attenuation of plaque progression and coronary calcification. This study aimed to compare the changes in atherosclerotic plaques and calcification of the coronary arteries in patients with atrial fibrillation (AF) treated with edoxaban and warfarin. A total of 150 OAC-naïve patients with AF and atherosclerotic lesions on coronary computed tomography angiography (CCTA) were enrolled and randomly assigned to the edoxaban or warfarin treatment groups. All enrolled patients received rosuvastatin 10 mg and 119 patients completed the entire study protocol. A total of 12 months after the assigned OAC treatment, follow-up CCTA was performed and changes in plaque and calcium volumes of the coronary arteries were analyzed. The baseline characteristics of the 2 groups were well-balanced. The percentage of time in therapeutic range in the warfarin group was 61.1%. Compared with the baseline CCTA, there was a significant reduction in plaque volume after 12 months of OAC and rosuvastatin administration in both groups, and the extent of regression did not differ significantly between the groups. The increase in calcium volume was greater in the warfarin group than in the edoxaban group; however, the difference was not significant. In OAC-naïve patients with AF and atherosclerotic coronary lesions who were treated with moderate-intensity statin, edoxaban use did not have a positive effect on atherosclerotic plaques and coronary calcification compared with warfarin use over a 12-month follow-up period.

Significance of Primary Melanoma Regression on Local Infiltrate and Outcome.

IntroductionThe characteristics and the prognostic value of regression in primary melanomas are controversial.ObjectivesTo further characterize “hot” and “cold” tumor’s stromas and to investigate the association between dermoscopy, pathology, and the prognostic implications of regression.MethodsA 14-year-collection-based retrospective analysis was carried out on 40 patients with confirmed regressive melanomas.ResultsThe extent of regression in dermoscopy was associated with the stage of the regression (P = 0.05) and with the MelanA patterns in histology (P = 0.02). Blue-gray and gray-brown color of the peppering (P = 0.01), and the eccentric, multifocal character of the dermoscopic regression (P = 0.05) were associated with “hot” stromas (CD8+, Granzym B+). Focal histologic regression (regressing melanomas) was associated with a good outcome (P < 0.001), while a complete regression (regressed melanomas) was associated with melanoma-related death (P < 0.001). “Hot” stromas (CD8+ were significantly associated with survival at 10 years (P = 0.044), while “hot” stromas (Granzyme B+) were associated with the locoregional extension (P = 0.016), and the initial distant metastasis (P = 0.016).ConclusionsDermoscopic features of regression in primary melanomas were associated with the stage of regression, its extent, and the “hot” or “cold” nature of the tumor stroma, with prognostic implications.

Intravascular extension of Wilms tumor: Characteristics of tumor thrombus and their impact on outcomes

Studies describing intravascular involvement in Wilms tumor have focused on illustrating individual institutional experience and the elements of surgical management. Thrombus characteristics like extent, patterns of regression, and correlation with the surgical findings, intraluminal adhesion, and viable tumor in the thrombus, and patency of the inferior vena cava (IVC) have not been systematically described. The aim of this study is to evaluate these thrombus characteristics and explore their impact on the overall outcomes. All patients with histologically confirmed Wilms tumors with intravascular thrombus diagnosed in the pediatric oncology unit of Tata Memorial Hospital registered from 2006 to 2019 were included. Data regarding clinical, radiological, and surgical particulars were retrieved from the prospectively maintained institutional database. Specific data for the thrombus included: distal extent before and after neoadjuvant chemotherapy, correlation of extent with the surgical findings, completeness of thrombectomy, the presence of a viable tumor in the thrombus, and the patency of the IVC. Survival analysis was performed utilizing the Kaplan-Meier method on SPSS software version 25. The study included 43 (9.9%) of the 432 patients with Wilms tumor having intravascular extension. Retrohepatic IVC (33.3%) followed by atrioventricular (26%) formed the frequent levels of thrombus with maximum regression occurring after chemotherapy in the latter (Summary figure). The overall concordance rate between computed tomography (CT) scan and surgical findings for the presence of thrombus was 86% and 4 patients had the thrombus limited to a lower level than the preoperative scan. At a median follow-up of 5-years, the 5-year event-free and overall survival was 81% and 82.2% respectively. Atrioventricular thrombus (p=0.003) and postoperative patency of IVC (p=0.02) were significantly associated with inferior survival, while the extent of regression, thrombus fracture, and viability was not significant. The findings of this study bring forth the characteristics of intravascular tumor thrombus affecting the outcomes which can be validated in future prospective studies. Although the ideal method for radiological assessment of the intravascular thrombus is elusive, CT scan provided adequate information for the presence and level of the intravascular thrombus with reasonable accuracy in this study. Study limitations include small sample size, the limited number of events, and lack of multivariate analysis to rule out confounding factors that could influence the observed findings. Atrioventricular thrombus and occlusion of IVC represent adverse prognostic factors. The extent of regression, fracture, and viability of thrombus did not affect survival in this study.

Incomplete structural reverse remodeling from late-stage left ventricular hypertrophy impedes the recovery of diastolic but not systolic dysfunction in rats.

Pressure overload-induced left ventricular myocardial hypertrophy (LVH) regresses after pressure unloading. However, distinct structural alterations become less reversible during the progression of LVH, which might influence the restoration of cardiac function. Here, we investigated how a reverse remodeling process from early versus late-stage LVH affects different aspects of left ventricular function. Pressure overload was induced in rats for 6, 12 and 18 weeks. Sham-operated animals were used as controls. Pressure unloading was evoked by removing the aortic constriction at week 6 (early-debanded) and week 12 (late-debanded). Echocardiography and histological analyses were carried out to detect structural alterations. Pressure-volume analysis was performed to assess left ventricular function. Molecular alterations were analyzed by quantitative real-time-PCR, and western blot. Myocardial hypertrophy regressed to a similar degree in early and late-debanded groups. Accordingly, no differences were detected in the extent of regression regarding left ventricular mass, cardiomyocyte diameter, heart weight-to-tibial length ratio and beta-to-alpha myosin heavy chain expression. In contrast, resorption of interstitial and perivascular myocardial fibrosis was only detected in the early-debanded group, whereas it persisted in the late-debanded group. Removing the aortic constriction normalized ventriculo-arterial coupling and increased systolic performance in both debanded groups. However, the residual dysfunction in active relaxation and passive stiffness was more severe in the late-debanded compared to the early-debanded group. Early debanding led to complete structural reverse remodeling (reduced hypertrophy and fibrosis) and full restoration of left ventricular function. In contrast, myocardial fibrosis persisted after late debanding, which impeded the normalization of diastolic but not systolic function.

An Echocardiographic Comparison of Sutureless and Conventional Aortic Valve Replacement: a Matched Case-Control Study

Background Patients at a high operative risk for conventional aortic valve replacement (AVR) may be offered sutureless valve implantation. Sutureless valves resemble conventional valves but incorporate an anchoring mechanism without using annular sutures. Methods Pre-operative and six month post-operative echocardiography data from our first year, single centre experience of sutureless valves was compared to conventional aortic valve replacements in patients matched for operative risk. Left ventricular ejection fraction, mean and peak AV gradients and inter-ventricular septal thickness, effective orifice area (EOA) and indexed effective orifice area (iEOA) were measured. Results The drops in mean and peak pre- to post-operative gradients were greater in the sutureless group, p=0.039 and p=0.001 respectively. Post-operative EOA was 1.69 cm2 and 1.26 cm2 (p=0.001) in the sutureless and conventional groups. Similarly iEOA was 0.93 cm2 and 0.74 cm2 (p=0.001) in the sutureless and conventional groups. There was also a reduction in patient prosthesis mismatch (PPM) in the sutureless group as compared to the conventional group (Chi square test p=0.026). Post-operative inter-ventricular septal thickness was 1.13 cm2 in the sutureless group and 1.35 cm2 in the conventional group (p=0.011). Conclusions Use of sutureless valves with a stent framework resulted in larger EOA and iEOA and a diminution in PPM; and lead to a statistically significant faster regression in inter-ventricular septal thickness that is a measure of left ventricular mass. The rate and extent of regression in left ventricular hypertrophy after AVR is important since it determines long-term survival including mortality, heart failure and decreased admission rates.

Active Neuroprotective Therapy of Acute Carotid Ischemic Stroke of Moderate Severity

Objective. To assess the efficacy of using a complex of neuroprotective agents in carotid ischemic stroke (IS). Materials and methods. An open, comparative study of combined neuroprotective therapy in the treatment of 25 patients with carotid IS of moderate severity in the acute period in comparison to standard therapy was performed. Patients of the study group received Gliatilin, Cytoflavin, and Actovegin daily for 15 days on the background of basal therapy. Patients were assessed every five days using the NIHSS scale and on day 21 using the Barthel index. Results and conclusions. By the end of treatment, the extent of regression of neurological impairments was significantly greater in patients receiving the combination of neuroprotectors. Better functional recovery by day 21 was obtained in patients of the study group, with positive changes in measures of inflammation and free radical processes.

Lower the Low-density Lipoprotein Cholesterol to the Level When You Born

Lower the Low-density Lipoprotein Cholesterol to the Level When You Born

Cutaneous regressing/regressed malignant melanoma: a clinicopathologic analysis of 8 cases

To study the clinicopathologic features and differential diagnosis of cutaneous regressing/regressed melanoma. Histopathologic evaluation and immunohistochemical study by EnVision method were performed in 8 cases of cutaneous regressing/regressed melanoma. The clinical presentation, treatment and follow-up data were analyzed. The age of the patients ranged from 40 to 69 years (mean 58 years). The male-to-female ratio was 3: 1. Tumors were located on the back (4 cases), sole of the foot (2 cases), ventral aspect of the toes (1 case), and the forearm (1 case). Clinically, 6 patients presented with progressive black mole of the skin, followed by subsequent focal hypopigmentation, even scarring. Two patients presented with multiple foci of dark-brown pigmentation. Microscopically, 3 cases were completely regressed malignant melanoma. Tumoral melanosis was found in 1 of 3 cases. The other 5 cases were melanoma with severe regression. The extent of regression ranged from 75% to 90%. The Breslow depth of the tumors ranged from 0.5 to 1.0 mm. Immunohistochemically, both metastatic and primary tumor cells were diffusely positive for S-100, HMB45 and Melan A, while melanophages were positive for CD68. Follow-up data were available in 8 patients, ranging from 8 to 27 months. Five patients were alive with no evidence of disease, 1 patient was alive with stable disease and 2 patients died of metastatic melanoma. Correlation between clinical presentation and pathologic features is important for diagnosis of cutaneous regressing/regressed melanoma. Thin melanoma with extensive regression ( ≥ 75%) should not been regarded as low metastatic risk and wide excision combined with sentinel lymph node biopsy is recommended.

Effectiveness of GP intervention on risk drinking clients: a re-analysis of data of the Florence early identification and brief intervention project

Although implementing brief intervention among risky clients by general practitioners (GPs) is part of public health efforts, a greater challenge is to evaluate the impact of such intervention. The authors re-examined the data elicited by a GP brief intervention project, which involved 308 risky drinkers among 2869 clients enrolled between 2005 and 2007 in two areas in and around Florence. Data presented in previous INEBRIA meetings showed that baseline risky drinkers had a 55.30 g/day average intake (60.15 g for males, 41.63 g for females), which decreased to 37.61 g/day at the first follow-up (41.71 g for males, 26.06 g for females). Regression to the mean methods (both uni- and multi-variate) were used to overcome possible statistical flaws. Applying the regression coefficient of the two series of measurements, the extent of regression to the mean was 6.77 g and 6.78 g for males and females. Therefore, the reduction of the consumption in grams between enrolment and the first follow-up has been transformed respectively into 11.67 and 8.80 g/day. This change does not appreciably alter the previous results. The GPs who identify between 8% and 20% of their patients as at-risk drinkers (which is the rate considered as more approximate to reality) had a statistically significantly higher number of patients showing up at follow-up (68.69%) compared to those who identify a lower ( 20 %) (p <0.001). Women compared to men, and people aged 40-49 compared to the other age classes, appear to be most amenable to change. Identification of risky drinking by GPs is a good predictor of decreased alcohol consumption among clients. Being a woman and being middle-aged are good predictors of improved alcohol drinking patterns among clients with at-risk drinking.

Dietary fenugreek seed regresses preestablished cholesterol gallstones in mice

An animal study was carried out to evaluate the influence of dietary fenugreek seeds on regression of preestablished cholesterol gallstones (CGS). CGS was induced by feeding a high-cholesterol diet for 10 weeks. After CGS induction, the animals were maintained for a further 10 weeks on experimental diets of high cholesterol, 6% fenugreek powder, 12% fenugreek powder, or basal control. Incidence of CGS and its severity were evaluated at the end of this feeding regimen. The incidence of CGS was significantly lowered as a result of dietary fenugreek seeds, the extent of regression being 61% and 64% in the low and high dose groups compared with 10% regression in the basal control group. The antilithogenic influence of dietary fenugreek was accompanied by significant reductions of more than 35% in serum cholesterol concentration. Hepatic cholesterol concentration was also profoundly lowered by dietary fenugreek, being 53%-63% lower than that of the basal control diet. Biliary cholesterol concentration was significantly lower as a result of dietary fenugreek during the post-CGS induction period, resulting in a decreased cholesterol:phospholipid ratio (0.44 and 0.40 compared with 0.79 in the basal control group). Biliary cholesterol : bile acid ratio was lowered by 67% and 73% upon feeding fenugreek, significantly lower than that in the basal control group. The cholesterol saturation index in the bile was also beneficially lowered by fenugreek treatment during the post-CGS induction period (the index was 0.90 and 0.42 compared with 1.86 in the basal control group). The present study provides evidence of the potency of hypolipidemic fenugreek seeds in regressing preestablished CGS, and this beneficial antilithogenic effect is attributable to its primary influence on cholesterol levels. This finding is significant in the context of evolving a dietary strategy to address CGS, which could help in preventing the incidence and regression of existing CGS and controlling possible recurrence.

Randomized Trial of Argon Plasma Coagulation Versus Endoscopic Surveillance for Barrett Esophagus After Antireflux Surgery: Late Results

To determine the efficacy of endoscopic argon plasma coagulation (APC) for ablation of Barrett esophagus. APC has been used to ablate Barrett esophagus. However, the long-term outcome of this treatment is unknown. This study reports 5-year results from a randomized trial of APC versus surveillance for Barrett esophagus in patients who had undergone a fundoplication for the treatment of gastroesophageal reflux. Fifty-eight patients with Barrett esophagus were randomized to undergo either ablation using APC or ongoing surveillance. At a mean 68 months after treatment, 40 patients underwent endoscopy follow-up. The efficacy of treatment, durability of the neosquamous re-epithelialization, and safety of the procedure were determined. Initially, at least 95% ablation of the metaplastic mucosa was achieved in all treated patients. At the 5-year follow-up, 14 of 20 APC patients continued to have at least 95% of their previous Barrett esophagus replaced by neosquamous mucosa, and 8 of these had complete microscopic regression of the Barrett esophagus. Five of the 20 surveillance patients had more than 95% regression of their Barrett esophagus, and 4 of these had complete microscopic regression (1 after subsequent APC treatment). The length of Barrett esophagus shortened significantly in both study groups, although the extent of regression was greater after APC treatment (mean 5.9-0.8 cm vs. 4.6-2.2 cm). Two patients who had undergone APC treatment developed a late esophageal stricture, which required endoscopic dilation, and 2 patients in the surveillance group developed high-grade dysplasia during follow-up. Regression of Barrett esophagus after fundoplication is more likely, and greater in extent, in patients who undergo ablation with APC. In most patients treated with APC the neosquamous mucosa remains stable at up to 5-year follow-up. The development of high-grade dysplasia only occurred in patients who were not treated with APC.

The Role of Statins in Reversing Atherosclerosis: What the Latest Regression Studies Show

Recent clinical trials confirm that aggressive lipid-lowering therapy with statins decreases low density lipoprotein (LDL) cholesterol to well below 100 mg/dL in high risk patients, and prevents cardiovascular events. Similarly, aggressive lipid lowering is being explored as a possible means of promoting regression of atherosclerosis and of affording greater protection from atherosclerotic events. A growing body of evidence indicates that intensive statin therapy, particularly in high risk patients, slows the rate of progression of atherosclerosis compared with moderate therapy, and that reductions of > or =40% in LDL cholesterol are necessary to achieve atherosclerosis regression. Questions remain regarding the extent of regression achieved with statin therapy and whether to dose statins to achieve a specific LDL-cholesterol level or a certain percent reduction; however, ongoing clinical trials may provide insight and guidance.

Do Pulmonary Autografts Provide Better Outcomes Than Mechanical Valves? A Prospective Randomized Trial

The objective of this study was to compare the performance of pulmonary autografts with mechanical aortic valves, in the treatment of aortic valve stenosis. Forty patients with aortic valve stenoses, and below the age of 55 years, were randomly assigned to receive either pulmonary autografts (n = 20) or mechanical valve (Edwards MIRA; Edwards Lifesciences, Irvine, CA) prostheses (n = 20). Clinical outcomes, left ventricular mass regression, effective orifice area, ejection fraction, and mean gradients were evaluated at discharge, 6 months, and one year after surgery. Follow-up was complete for all patients. Hemodynamic performance was significantly better in the Ross group (mean gradient 2.6 mm Hg vs 10.9 mm Hg, p = 0.0005). Overall, a significant decrease in left ventricular mass was found one year postoperatively. However, there was no significant difference in the rate and extent of regression between the groups. There was one stroke in the Ross group and one major bleeding complication in the mechanical valve group. Both patients recovered fully. In our randomized cohort of young patients with aortic valve stenoses, the Ross procedure was superior to the mechanical prostheses with regard to hemodynamic performance. However, this did not result in an accelerated left ventricular mass regression. Clinical advantages like reduced valve-related complications and lesser myocardial strain will have to be proven in the long term.

Estimating the effect of regression toward the mean under stochastic censoring.

This investigation estimated regression toward the mean in the evaluation of a blood cholesterol educational program in which the probability of return for a follow-up measure was positively related to the initial measure--a situation the authors term "stochastic censoring." The situation in which selection is by a fixed cutpoint is well known. The authors estimate the extent of regression toward the mean when selection is probabilistically related to an initially higher blood cholesterol level. A Monte Carlo method is proposed, conditional on the observed data, for estimating the regression toward the mean and its precision. In 106 simulations, regression toward the mean was estimated to be 0.012 mmol/liter (standard deviation (SD), 0.032 mmol/liter). Similar estimates were obtained using Empirical Bayes shrinkage estimates of baseline cholesterol (regression toward the mean = 0.0106 mmol/liter) and numeric integration (0.0109 mmol/liter). The observed reduction in blood cholesterol was 0.271 mmol/liter (SD, 0.061 mmol/liter); after correction for regression toward the mean, the estimate of the true educational effect was 0.259 mmol/liter (SD, 0.069 mmol/liter). Functions are presented that will enable investigators to predict regression toward the mean and its standard deviation under the conditions that errors are gaussian and stochastic censoring can be approximated by a logistic model.

Genes, environment, and addictive behavior: etiology of individual differences and extreme cases

There is considerable interest in assessing the role of genetic factors in the aetiology of addiction. This paper reviews the possible contribution of a new quantitative technique, termed DF analysis after its originators DeFries & Fulker. DF analysis provides a way of examining whether aetiological factors relating to addiction as a discrete disorder (manifest as extreme scores on a diagnostic instrument) are similar to or different from those that relate to it as a continuum. For example, it is possible to estimate the contribution of familial factors to the development of a clinical condition defined in terms of an extreme score on an instrument by examining the extent of regression towards the unselected population mean of siblings' scores on that instrument. At the same time it is possible to estimate familial influences on the full range of values by examining the correlation between the scores of siblings. Insofar as the two methods produce different estimates, it is possible to infer different levels of involvement of familial factors for extreme cases than for the continuum as a whole. Information provided by such analyses could be critical when constructing models of addictive disorders and help direct more specific studies isolating particular mechanisms.

Regression of left ventricular hypertrophy.

Since our first studies on hypertrophy regression, this parameter has achieved an increasing interest in the treatment of hypertension. During the past 8 years we studied different groups of antihypertensive drugs with the use of magnetic resonance imaging (MRI). This article discusses the antihypertensive drug carvedilol. We examined 17 patients with diastolic blood pressure of at least 95 mm Hg and left ventricular wall thickness of at least 15 mm. Measurements were carried out before and after treatment with 25 mg/day carvedilol for 6 months. We demonstrated a significant regression of septal thickness from 17.7 to 16.3 mm. At each wall, three measurements at different points were performed by MRI and the means were calculated. Left ventricular ejection fraction and wall motion did not show any significant changes in radionuclide ventriculography after treatment. The diastolic blood pressure was reduced from 98.0 to 88.7 mm Hg. All differences are significant (p less than 0.05). There was no significant correlation between the extent of regression of septal hypertrophy and the degree of pretherapeutic hypertrophy, the age of patients, or the dimension of blood pressure reduction.

Thin Malignant Melanomas With Regression and Metastases

The significance of partial regression in thin malignant melanomas (0.76 mm or less) of the skin was evaluated to determine if the regression was associated with the later development of metastases in patients who previously were considered to have a favorable prognosis. Of 575 patients with primary cutaneous melanoma treated and followed up by the Division of Surgical Oncology at the University of Illinois, Chicago, we found that 103 (18%) had tumors that measured less than 0.76 mm. Of these, 30 (29%) showed histologic evidence of partial regression. In six (20%) of the 30 patients, visceral metastases developed and the patients died. All six had more than 77% regression of their primary tumors. Of the remaining 24 patients, only one had regression greater than 77% and she is still alive three years after diagnosis. Most of these 24 (83%) patients had regression of less than 50% (mean, 29.9%). No metastasis occurred in the 73 patients who had thin melanomas without histologic evidence of regression. It is apparent from this study that patients with thin melanomas who show partial regression cannot be included in the "low-risk" group if the extent of regression is 75% to 80% or more.

大動脈および冠状動脈硬化の退縮

Controversy exists as to whether atherosclerotic lesions were reversible or not. These conflicting views mainly derived from differences of animal species, experimental designs, or methods of evaluation. In the present study we attempted to quantitate sequential changes of sclerotic lesions with an aid of the image processing system.Normotensive and renovascular-hypertensive rabbits were placed on a 0.5% cholesterol diet for 16 weeks and observed up to 120 weeks. After measuring surface involvement (SI) by the point counting method, a representative longitudinal section covering the whole length of the aorta was obtained, and histometric quantitative analysis was carried out concerning foam cell infiltration, fibromuscular proliferation, and atheroma formation. In addition, 10 continuous step sections of the left coronary artery (and its branches) was prepared, and the degrees of luminal stenosis were estimated in all arterial segments contained in the sections.After stopping of cholesterol feeding, foam cell lesion of the aorta and coronary artery was gradually replaced by fibromuscular tissue. A greater degree of smooth muscle cell proliferation was a feature of hypertensive animals. Formation of atheroma occurred almost invariably after 12 weeks return to the normal diet. It was noted that hypertension accentuated the severity and extent of both aortic and coronary lesions.Evidence of regression of nonatheromatous as well as atheromatous lesions was obtained in normotensive rabbits (and partially in hypertensive rabbits) sacrificed after 44 weeks return to the normal diet. Significant reduction of coronary lesions with luminal narrowing of more than 60 % were also documented in both normotensive and hypertensive animals. In conclusion, the present study indicated that, even in the hypertensive animals, regression of both aortic and coronary lesions of the rabbits could occur following a long period of dietary manipulations. The extent of regression, however, appeared to be less prominent, when compared with several observations demonstrated in monkeys.

Age difference in endogenous opiate modulation of short photoperiod-induced testicular regression in golden hamsters

Effects of age and naloxone on testicular function were studied in golden hamsters exposed to short photoperiods. Subjection of hamsters to short photoperiods of 6 h light: 18 h darkness for 6 weeks led to testicular regression in young adult (5-6 months) or middle-aged (11-12 months) golden hamsters but not in prepubertal hamsters of 1-2 months of age. The middle-aged hamsters had decreased testis width by week 4 of treatment and the young hamsters by week 5. Daily injection of naloxone at the time of 'lights on' partially prevented testicular regression in young and middle-aged hamsters but the extent of regression was significantly greater in the middle-aged animals. Plasma LH and FSH concentrations were significantly reduced in hamsters placed in short photoperiods regardless of age or testicular weight, while naloxone treatment significantly increased the LH concentrations in all age groups. Plasma beta-endorphin-like immunoreactivity was significantly increased by short photoperiod or older age. These results indicated that (a) the sensitivity of the testicular suppression to short photoperiod increases as a function of age, (b) naloxone, a specific opiate receptor blocker, can partially prevent short photoperiod-induced testicular regression and (c) ageing and short photoperiods increase beta-endorphin-like immunoreactivity. It is concluded that the opiate system may be involved in ageing and photoperiod regulation of reproductive function.

Prognostic Significance of Extent of Tumor Regression at Completion of Radiation Therapy

If among tumors of a given volume and anatomical site there were subpopulations which differed in their local radiocontrollability or TCD502 (radiation dose that Yields a 50 per cent local control rate) and if these groups had distinguishing clinical characteristics, the radiotherapist could administer reduced radiation doses to the low TCD50 cases. This would lessen the likelihood of complication in that group of cases for a specified local control rate. For the higher TCD50 groups, either the treatment could be carried to maximum tolerable radiation doses by complex technics or the patient could be referred for surgery. In our center, decision as to the final radiation dose to be used in the treatment of individual squamous-cell carcinomas of the head and neck region has been based on the tacit assumption that each tumor at a specified site and a given volume could be classified as of a low, standard, or high local radiocontrollability group by observing the extent of regression of tumor volume at the c...