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Biomedical subjects

A Porter

Publications and source records attributed to A Porter.

At least 37 records · Page 2Linked to original sources
PubMed1999

The natural history of aortic valve disease after mitral valve surgery.

OBJECTIVES: The present study evaluates the long-term course of aortic valve disease and the need for aortic valve surgery in patients with rheumatic mitral valve disease who underwent mitral valve surgery. BACKGROUND: Little is known about the natural history of aortic valve disease in patients undergoing mitral valve surgery for rheumatic mitral valve disease. In addition there is no firm policy regarding the appropriate treatment of mild aortic valve disease while replacing the mitral valve. METHODS: One-hundred thirty-one patients (44 male, 87 female; mean age 61+/-13 yr, range 35 to 89) were followed after mitral valve surgery for a mean period of 13+/-7 years. All patients had rheumatic heart disease. Aortic valve function was assessed preoperatively by cardiac catheterization and during follow-up by transthoracic echocardiography. RESULTS: At the time of mitral valve surgery, 59 patients (45%) had mild aortic valve disease: 7 (5%) aortic stenosis (AS), 58 (44%) aortic regurgitation (AR). At the end of follow-up, 96 patients (73%) had aortic valve disease: 33 AS (mild or moderate except in two cases) and 90 AR (mild or moderate except in one case). Among patients without aortic valve disease at the time of the mitral valve surgery, only three patients developed significant aortic valve disease after 25 years of follow-up procedures. Disease progression was noted in three of the seven patients with AS (2 to severe) and in six of the fifty eight with AR (1 to severe). Fifty two (90%) with mild AR remained stable after a mean follow-up period of 16 years. In only three patients (2%) the aortic valve disease progressed significantly after 9, 17 and 22 years. In only six patients of the entire cohort (5%), aortic valve replacement was needed after a mean period of 21 years (range 15 to 33). In four of them the primary indication for the second surgery was dysfunction of the prosthetic mitral valve. CONCLUSIONS: Our findings indicate that, among patients with rheumatic heart disease, a considerable number of patients have mild aortic valve disease at the time of mitral valve surgery. Yet most do not progress to severe disease, and aortic valve replacement is rarely needed after a long follow-up period. Thus, prophylactic valve replacement is not indicated in these cases.

Adolescent↗
PubMed1999

Sign-language interpretation in psychotherapy with deaf patients.

Sporadic encounters with deaf patients seeking psychotherapy present a challenge to general clinicians outside of specialized services for the deaf. Skills for working with people who do not share one's own language mode and culture are not routinely taught in most training programs, so clinicians may be unprepared when they first encounter a deaf patient. While it would be ideal to be able to match deaf patients with therapists fluent in their preferred language mode, this is often not feasible in smaller centers. Working with a trained professional sign-language interpreter can be a productive alternative, as long as patient, therapist, and interpreter understand and are comfortable with the process. Peer-reviewed literature on sign language interpretation in psychotherapy is sparse, but some practical guidelines can be gleaned from it and supplemented by information provided by the deaf community through the Internet. This paper arose from one psychiatric resident's first experience of psychotherapy working with a sign-language interpreter, and summarizes the literature search that resulted from a quest for understanding of deaf culture and experience, of the unique characteristics of sign language, and of the effects on the therapeutic relationship of the presence of the interpreter.

Adult↗
PubMed1999

The parturition defect in steroid 5alpha-reductase type 1 knockout mice is due to impaired cervical ripening.

Successful delivery of the fetus (parturition) depends on coordinate interactions between the uterus and cervix. A majority (70%) of mice deficient in the type 1 isozyme of steroid 5alpha-reductase fail to deliver their young at term and thus manifest a parturition defect. Using in vitro and in vivo measurements we show here that rhythmic contractions of the uterus occur normally in these mutant mice at the end of gestation. In contrast, the cervix of the mutant animal fails to ripen at term as judged by biomechanical, histological, and endocrinological assays. Impaired metabolism of progesterone in the cervix of the mutant mice in late gestation leads to an accumulation of this steroid in the tissue. We conclude that a failure of cervical ripening underlies the parturition defect in mice lacking steroid 5alpha-reductase type 1 and that this enzyme normally plays an essential role in cervical progesterone catabolism at the end of pregnancy.

20-alpha-Dihydroprogesterone↗
PubMed1999

Tricuspid regurgitation late after mitral valve replacement: clinical and echocardiographic evaluation.

BACKGROUND AND AIM OF THE STUDY: Significant tricuspid regurgitation (TR) can contribute to increased morbidity and mortality in patients after mitral valve replacement (MVR), both in the immediate and late postoperative period. The aim of this study was to evaluate the prevalence and the clinical importance of TR late after MVR, as assessed both clinically and echocardiographically. METHODS: The study group comprised 65 patients (39 women, 26 men; mean age 61+/-12 years) with rheumatic heart disease who had undergone MVR without tricuspid valve surgery between one and 30 years (mean 11.3+/-8 years) before their last clinical examination. All patients underwent a complete color-Doppler echocardiographic examination. The predominant presurgical mitral lesion was stenosis in 44 patients and regurgitation in 21. The severity of the tricuspid valve disease was assessed echocardiographically using color-Doppler flow images and flow direction in the inferior vena cava or hepatic veins, and by clinical evaluation. RESULTS: Echocardiography revealed significant late TR in 44 patients (67%), which was moderate in 16 and severe in 28, and evident on physical examination in 24 cases (37%). Age (relative risk (RR) = 1.1; C.I. 1-1.1) and female sex (RR = 1.8; C.I. = 1.0-3.2) were identified as statistically significant predictors for late clinical TR development, but only age was found as a statistically significant predictor for echocardiographic TR development. An elevated RR for organic TR and predominant mitral regurgitation was found. In contrast, pre- and postoperative pulmonary artery pressure, predominant mitral lesion, prosthetic valve gradient and regurgitation were similar in patients with and without late TR. CONCLUSIONS: Significant TR diagnosed by echocardiography late after MVR is common, and clinically evident in more than one-third of patients. Therefore, a lower threshold for tricuspid valve repair should be considered when mitral valve surgery is carried out.

Aged↗
PubMed1998

Mitral annular calcium detected by transthoracic echocardiography is a marker for high prevalence and severity of coronary artery disease in patients undergoing coronary angiography.

This study tests the hypothesis that mitral annular calcium (MAC) detected by transthoracic echocardiography (TTE) is a marker for high prevalence and severity of coronary artery disease (CAD) in patients undergoing coronary angiography. Pathological studies have suggested that there is an association between MAC and calcific deposits in coronary arteries; however, there are no clinical data to support this association. One hundred sixty-five patients with MAC (101 women and 64 men; mean age 71 +/- 8 years) who underwent cardiac catheterization with coronary angiography for various reasons were compared with 147 age-matched controls without MAC who underwent coronary angiography for the same indications during the same period. MAC was defined as a dense, localized, highly reflective area at the base of the posterior mitral leaflet detected by TTE. Obstructive CAD was defined as either > or = 50% reduction of the internal diameter of the left main coronary artery or > or = 70% reduction of the internal diameter of the left anterior descending, right coronary, or left circumflex artery distribution. Compared with controls, the MAC group had a significantly higher prevalence of CAD (89% vs 75%, p = 0.001) and higher rates of 3-vessel disease (45% vs 24%, p = 0.001) and left main CAD (13% vs 5%, p = 0.009). Nonsignificant CAD was more common in the control group (25% vs 11%, p = 0.001). Multivariate analysis identified MAC (p = 0.0002), indications for cardiac angiography (p = 0.02), sex (p = 0.03), and diabetes mellitus (p = 0.03) as independent predictors for the presence and severity of obstructive CAD. MAC detected by TTE may be a marker for high prevalence and severity of CAD in patients undergoing coronary angiography.

Adult↗
PubMed1998

Prostate-specific antigen levels are higher in African-American than in white patients in a multicenter registration study: results of RTOG 94-12.

PURPOSE: To compare serum prostate-specific antigen (PSA) levels in a national sample of African-American and white men with prostate cancer, and to attempt to explain any differences by using self-reported individual-level socioeconomic status adjustments. METHODS AND MATERIALS: During 4 1/2 months in 1994-95, 709 patients with nonmetastatic prostate cancer were enrolled in this prospective study; 17.5% were African-American and 82.5% were white. Information about clinical stage, tumor grade, pretreatment PSA, type of insurance, and educational and income status was obtained. Serum PSA levels were measured and racial differences were found; how the differences were influenced by other patient- or tumor-related factors and if the differences could be explained by socioeconomic status disparities were determined. In univariate analyses, factors associated with the mean PSA levels were studied; log-converted values were used to yield a normal distribution. Multivariate analyses were done on log-linear models for description of association patterns among various categorical variables; a perfectly fitted model should have a correlation value (CV) of 1.0. RESULTS: The mean PSA level was higher in African-Americans (14.68 ng/ml) than in whites (9.82 ng/ml) (p = 0.001). Clinical stage (p = 0.001), Gleason sum tumor grade (p = 0.0001), educational level (p = 0.001), and household income (p = 0.03) were also associated with mean PSA levels; age, type of biopsy, and insurance status were not. Disease stage (p = 0.0001), grade (p = 0.0001), education (p = 0.07), and income (p = 0.02) were all associated with PSA levels for whites, but none of these factors were important for African-Americans (all p values > 0.1). The best fitted log-linear model (CV = 0.99) contained PSA (< 10, 10-20, and > 20), Gleason sum grade (2-5, 6-7, and 8-10), race, and two interactions: PSA by race (p = 0.0012) and PSA by Gleason sum (p = 0.0001). Models replacing race for either income (CV = 0.82) or education (CV = 0.82) or both (CV = 0.78) did not fit as well. CONCLUSIONS: African-Americans with nonmetastatic prostate cancer have higher serum PSA levels at diagnosis than whites, implying a higher tumor cell burden. Individual-level household income, education, or insurance status alone or in combination account for racial differences, but only partially.

Analysis of Variance↗
PubMed1998

Value of T-wave direction with lead III ST-segment depression in acute anterior wall myocardial infarction: electrocardiographic prediction of a "wrapped" left anterior descending artery.

BACKGROUND: Lead III ST-segment depression during acute anterior wall myocardial infarction (AMI) has been attributed to reciprocal changes. However, the value of the T-wave direction (positive or negative) in predicting the site of obstruction and type of the left anterior descending (LAD) artery is not clear and has not been studied before. HYPOTHESIS: The aim of the study was to assess retrospectively the correlation between two patterns of lead III ST-segment depression, and type of LAD artery and its level of obstruction during first AMI. METHODS: The study group consisted of 48 consecutive patients, admitted to the coronary care unit for first AMI, who showed ST-segment elevation in lead a VL and ST-segment depression in lead III on admission 12-lead electrocardiogram. The patients were divided by T-wave direction into Group 1 (n = 31), negative T wave, and Group 2 (n = 17), positive T wave. The coronary angiogram was evaluated for type of LAD ("wrapped", i.e., surrounding the apex or not), site of obstruction (pre- or postdiagonal branch), and other significant coronary artery obstructions. RESULTS: Mean lead III ST-segment depression was 1.99 +/- 1.32 mm in Group 1 and 1.13 +/- 0.74 mm in Group 2 (p = 0.004); mean ST-segment elevation in a VL was 1.35 +/- 0.84 mm and 1.23 +/- 0.5 mm, respectively (p = 0.5). A wrapped LAD was found in 12 patients (38.7%) in Group 1 and in 13 in Group 2 (76.4%) (p = 0.02). The sensitivity of lead III ST-segment depression with positive T wave to predict a wrapped LAD was 52%, and the specificity was 82% with a positive predictive value of 76%. On angiography, 25 patients (80%) in Group 1 and 13 (76%) in Group 2 had prediagonal occlusion of the LAD (p = 0.77). No significant difference between groups was found for right and circumflex coronary artery involvement or incidence of multivessel disease. CONCLUSIONS: The presence of lead III ST-segment depression with positive T wave associated with ST-segment elevation in a VL in the early course of AMI can serve as an early electrocardiographic marker of prediagonal occlusion of a "wrapped" LAD.

Case-Control Studies↗
PubMed1998

Controlling your losses: conditional gene silencing in mammals.

Methods are now widely used in mice, and to a lesser extent in mammalian-cell culture, for the constitutive silencing of target genes in order to assess their function. For a variety of reasons, not least because many genes are essential for viability, it is important that these methods can be adapted to allow the controlled silencing of target genes. Reviewed here are the ways in which gene-silencing methods can be combined with a growing number of genetic control systems to generate cell lines or mice that are, in effect, conditional mutants. These approaches are still being developed and promise to open up key areas of cell and animal biology to genetic analysis.

Animals↗
PubMed1998

Evaluation of tricuspid regurgitation severity: echocardiographic and clinical correlation.

The correlation between 19 echocardiographic markers of tricuspid regurgitation (TR) severity and findings on physical examination was studied in 66 consecutive patients (age 63 +/- 12 years) with moderate or severe TR. Clinical TR was defined by two or more of the following: prominent jugular venous pulse V waves, pulsating liver, and sea-saw parasternal movement. Thirty-eight patients (57.6%) had clinical TR, whereas 28 patients (42.4%) did not. In a univariate analysis, the most powerful predictors of clinical TR (p < 0.01) were jet area > or =9 cm2, right atrial area > or =30 cm2, jet width at origin > or =0.8 cm, systolic flow reversal in the hepatic veins, paradoxical septal movement, diastolic septal flattening, inferior vena cava diameter > or =2.1 cm, and lack of inferior vena cava respiratory variation. Regurgitant index was a weaker predictor. Multivariate analysis showed that the only independent echocardiographic predictor of clinical TR was systolic flow reversal (positive and negative predictive values 91.2% and 78.1%, respectively). Significant echocardiographic TR can be subclinical in a substantial number of patients.

Adult↗
PubMed1998

Are there differences among patients with inferior acute myocardial infarction with ST depression in leads V2 and V3 and positive versus negative T waves in these leads on admission?

We assessed whether there are differences among patients with inferior acute myocardial infarction and ST segment depression in leads V2-V3 between those with positive versus negative T waves on admission. We found no differences in the prevalence of concomitant significant left anterior descending coronary artery stenosis and anterior or posterior wall motion abnormalities on echocardiography between the two groups. Precordial ST segment depression with negative T wave may be the early electrocardiographic pattern of posterior infarction, reflecting ST segment elevation with positive T waves that would have been detected by leads facing the posterior wall.

Cohort Studies↗
PubMed1997

Androgen suppression plus radiation versus radiation alone for patients with D1 (pN+) adenocarcinoma of the prostate (results based on a national prospective randomized trial, RTOG 85-31). Radiation Therapy Oncology Group.

PURPOSE: To evaluate the effect of immediate androgen suppression in conjunction with standard external beam irradiation vs. radiation alone on a group of pathologically staged lymph node-positive patients with adenocarcinoma of the prostate. METHODS AND MATERIALS: A national prospective randomized trial (RTOG 85-31) of standard external beam irradiation plus immediate androgen suppression vs. external beam irradiation alone was initiated in 1985 for patients with locally advanced adenocarcinoma of the prostate. One hundred seventy-three of the patients in this trial had biopsy-proven pathologically involved lymph nodes. Ninety-eight of these patients received radiation plus the immediate androgen suppression (LHRH agonist), while 75 received radiation alone with hormonal manipulation instituted at the time of relapse. RESULTS: With a median followup of 4.9 years, estimated progression-free survival with PSA < 1.5 ng/ml at 5 years was 55% for the patients who received radiation plus immediate LHRH agonist vs. 11% of the patients who received radiation alone with hormonal manipulation at relapse (p = 0.0001). Because all of these patients had locally advanced disease (i.e., pathologically positive lymph nodes), stage does not explain this difference in outcome, and Gleason grade was not statistically different between the two groups. Estimated absolute survival at 5 years for the radiation and LHRH group was 73 vs. 65% for the radiation alone group who received androgen suppression at relapse. Estimated disease-specific survival at 5 years was 82% for the radiation and immediate LHRH agonist group and 77% for the radiation-alone group. CONCLUSION: Patients with adenocarcinoma of the prostate and pathologically involved pelvic lymph nodes (pN+ or clinical stage D1) should be seriously considered for external beam irradiation plus immediate hormonal manipulation over radiation alone with hormonal manipulation at the time of relapse.

Adenocarcinoma↗
PubMed1997

Postoperative radiation for cervical cancer with pathologic risk factors.

PURPOSE: To examine the efficacy of postoperative radiation therapy for early-stage cervical cancer with pathologic risk factors. METHODS AND MATERIALS: We reviewed the charts of 83 patients who received postoperative radiation therapy at our facility from March 1980 to November 1993 for early stage cervix cancer with positive surgical margins, positive pelvic or periaortic lymph nodes, lymphovascular space invasion, deep invasion, or for disease discovered incidently at simple hysterectomy. Twenty-eight patients received low dose rate (LDR) intracavitary radiation with or without external beam pelvic irradiation and 55 patients received external beam pelvic irradiation with high dose rate (HDR) intracavitary implants. Of these 83 patients, 66 were evaluable--20 LDR and 46 HDR patients. All patients received 45-50 Gy external beam irradiation and 20 Gy LDR equivalent intracavitary irradiation prescribed to 0.5 cm below the mucosa. Ninety percent of the LDR group and 92% of the HDR group completed treatment within < 56 days. Treatment-related toxicities were scored according to the GOG toxicity scale. Mean and median follow-up times were 101 months and 111 months (3-172 months) for the LDR group and 42 and 40 months (3-98 months) for the HDR group. RESULTS: The 5-year disease-free survival was 89% for the LDR group and 72% for the HDR group. Local control was observed in 90% (18 out of 20) of the LDR patients and 89% (41 out of 46) of the HDR patients for an overall local control rate of 89.5%. Two of 20 LDR patients (10%) experienced recurrence (two pelvic with distant metastasis). Nine of 46 HDR patients (22%) had recurrence of disease (three pelvic, four distant metastasis, and two pelvic with distant metastasis). In the HDR group, 6 out of 16 (38%) with positive lymph nodes died of disease whereas, 27 out of 30 (90%) of the patients with negative lymph nodes remain free of disease. Three of 20 (15%) LDR patients and 4 out of 46 (9%) HDR patients experienced Grade 2 or 3 late treatment- related complications. No patient in either group had Grade 4 or 5 complications. Pathologic risk factors were analyzed. Lymph node positivity and lymphovascular space invasion were found to be significant (p = 0.01 and p = 0.02). Positive margins, deep invasion, and age were not significant. CONCLUSION: Our results demonstrate the efficacy of postoperative irradiation for cervical cancer with pathologic risk factors. Overall, the local control rate was 89.5% The HDR results demonstrate that this method can be delivered safely and effectively.

Adult↗