Biomedical subjects

L B Reeder

Publications and source records attributed to L B Reeder.

14 recordsLinked to original sources

PubMed2001

Malignant pleural effusions.

Malignant pleural effusions contribute to considerable morbidity in cancer patients and generally portend an overall poor prognosis. Treatment of malignant pleural effusions is palliative; therefore, quality of life issues, as well as the risks and benefits of the therapeutic options, become more critical. In my opinion, factors such as in patient versus outpatient management and associated procedural discomfort are important in the decision-making process, and the patient should participate in these subjective considerations. It is difficult to compare results and determine the true efficacy of different techniques and agents because endpoints and response criteria as well as the extent and method of follow-up vary. In addition, the etiology of the primary complaint, dyspnea, is frequently multifactorial. However, malignant effusions recur, and therefore repeated thoracentesis, especially if the fluid rapidly reaccumulates, is usually not a good long-term solution unless the patient's overall prognosis and current condition prohibits a more invasive option. The standard option for recurrent effusions is insertion of a chest tube. If the lung re-expands, chemical pleurodesis is attempted to achieve adherence of the visceral to the parietal pleura. Sterilized talc is the best sclerosant; it has good efficacy and cost effectiveness and can be administered easily as a slurry at the bedside via a chest tube with minimal patient discomfort and without more aggressive and invasive procedures.

Humans↗

PubMed2000

Neurogenic tumors of the mediastinum.

Neurogenic tumors can arise from neural cells in any location; however, they commonly are found in the mediastinum and, more specifically, most often are located in the posterior compartment. Neurogenic tumors can be benign or malignant, with a wide array of both clinical and pathologic features that are commonly classified by the cell type of origin. These tumors are usually detected on routine chest radiograph, and a computed tomographic scan is required to obtain more information about involvement of local structures. A magnetic resonance imaging scan may be necessary if a dumbbell-shaped component is identified or suspected. Treatment options vary depending on the presentation, but most often surgical resection is recommended. Whereas patients with benign neurogenic tumors have an excellent prognosis with complete surgical resection, patients with malignant neurogenic tumors still have poor long-term survival prospects.

Ganglioglioma↗

PubMed1996

Endothelin-1 synthesis and receptor-mediated activity in porcine lymph vessels.

Endothelin-1 (ET-1) is a potent vasoconstrictor of blood vessels and interacts with nitric oxide (NO) to regulate vascular tone. We hypothesized that ET-1 may modulate lymph vessel tone via local synthesis, receptor-mediated vasoconstriction, and interaction with NO. Serial sections obtained from formalin-fixed porcine mediastinal tissue, incubated with either ET-1 or von Willebrand factor antibody and stained with avidin-biotin complex and peroxidase, demonstrated ET-1 in lymphatic vascular endothelium. Isometric tension was recorded in vitro in fresh porcine tracheo-bronchial lymph vessel rings in response to the cumulative addition of ET-1 (10(-11) to 10(-6) M). ET-1 induced a tonic contraction with peak tension at 3 x 10(-7) M (mean tension 3731 +/- 306 mg; 259 +/- 20 percent of response to 65 mM KCl). The addition of specific receptor antagonists (ET(A) (BQ-610), ET(B) (BQ-788), or both) blocked the contractile response seen in ET-1 stimulated controls (ET(A) + ET(B) > ET(A)>> ET(B). The response to ET-1 was increased by endothelial damage but was unaffected by the inhibition of NO synthesis by N (G)-monomethyl-L-arginine (L-NMMA) Endothelial damage altered the ET-1 response in the presence of ET(B) antagonist but not ET(A) antagonist. ET-1 is a potent endothelium-derived vasoconstrictor of lymph vessels. Its effects are mediated through specific receptors, are not importantly modulated by NO, but may be modified by release of other endothelium-derived relaxing factors. We conclude that lymph vessel tone may be regulated by ET-1.

Analysis of Variance↗

PubMed1996

Characterization of the effects of histamine in porcine tracheobronchial lymph vessels.

We characterized the responses of lymphatic vascular smooth muscle to histaminergic-receptor stimulation and blockade and explored the mechanisms underlying the histamine-stimulated release of endothelium-derived relaxing factor (EDRF). Fresh porcine tracheobronchial lymph vessel rings mounted in organ baths were stimulated by the cumulative addition of histamine or H1, H2, and H3 receptor-specific agonists in the presence or absence of receptor-specific antagonists. Histamine had a contractile effect on lymphatic vascular smooth muscle that was H1 receptor mediated. No important effects were elicited by H2- or H3-receptor stimulation. Histamine also caused the release of EDRF as demonstrated by an increase in smooth muscle tone in the absence of endothelium and after inhibition of nitric oxide synthase. This effect was strong at high concentrations of histamine and was mediated by H1-receptor stimulation. The results suggest that histamine may contribute to the regulation of lymphatic vascular smooth muscle tone under pathological conditions, an effect that may be controlled through modification of H1-receptor activity.

Animals↗

PubMed1996

Results of myotomy and partial fundoplication after pneumatic dilation for achalasia.

BACKGROUND: We questioned whether results of myotomy for achalasia are influenced by previous pneumatic dilation and whether surgical outcome is influenced by a dilation-related perforation necessitating urgent operation. METHODS: We performed a retrospective analysis of 60 patients who underwent transthoracic myotomy and fundoplication from 1977 to 1995. Dysphagia, heartburn, pain, and regurgitation were scored on a scale of 0 to 3 and results were classified according to combined symptom score. RESULTS: Dilation was performed before myotomy once in 15 patients, twice in 25, 3 times or more in 9, and never in 11 patients. Operation was urgent due to perforation in 6 patients (10%). There was no postoperative leak or mortality. Overall symptom score at last follow-up (57 +/- 8 months; 90% of patients) was improved compared with preoperative score (2.1 +/- 0.3 months versus 5.1 +/- 0.2 months; p < 0.0001). Outcome was unrelated to whether or not a perforation occurred (excellent/good outcomes in 100% and 88%, respectively) or to whether or not preoperative dilations had been performed (excellent/good outcomes in 90% and 89%, respectively). CONCLUSIONS: Myotomy and partial fundoplication is an effective technique for management of achalasia. Results are unaffected by the need for urgent operation for perforation and are unrelated to whether pneumatic dilation is performed preoperatively.

Adolescent↗

PubMed1995

Intensive multimodality therapy for carcinoma of the esophagus and gastroesophageal junction.

BACKGROUND: We designed a trial of intensive multimodality therapy for carcinoma of the esophagus and gastroesophageal junction to assess tumor response and operability after neoadjuvant chemotherapy and to determine the impact of trimodality therapy on longterm survival. METHODS: Thirty-two patients with resectable (clinical stage IIa, n = 17; IIb, n = 1; III, n = 14) squamous cell cancer (n = 15) or adenocarcinoma (n = 17) were treated with neoadjuvant chemotherapy (cisplatin, 5-fluorouracil, leukovorin), resection, and postoperative chemoradiotherapy (hydroxyurea, 5-fluorouracil; 50-66 Gy). RESULTS: Use of neoadjuvant chemotherapy yielded the following results: a measurable clinical response in 22 patients, stable disease in eight patients, disease progression in one patient, and death in one patient. Thirty-one patients underwent resection, with the following results: two operative deaths (6.5%) and nonfatal morbidity in 17 (59%); the median hospital stay was 13 days. Pathologic staging was stage 0, n = 1; I, n = 2; IIa, n = 11; IIb, n = 5; III, n = 7; and IV, n = 5. Postoperative chemoradiotherapy was completed in 23 patients with one death, for an overall treatment-related mortality rate of 12.5% (four of 32). At a mean follow-up of 22.5 months, median survival is 19.7 months and 14 patients are alive and disease free. CONCLUSIONS: Neoadjuvant therapy for cancer of the esophagus and cardia results in good tumor response. Esophagectomy in this setting can be accomplished with acceptable morbidity and mortality. Results of an interim analysis of survival are encouraging and suggest that further investigation of this regimen is warranted.

Adenocarcinoma↗

PubMed1995

Recurrent spontaneous perforation of the esophagus.

Boerhaave's syndrome is uncommon and its precise etiology is unclear. Information regarding the long-term outcome of patients surviving this injury is lacking. We present the case of a patient who suffered two spontaneous perforations of the esophagus that occurred 30 years apart.

Aged↗

PubMed1995

Current results of therapy for esophageal perforation.

BACKGROUND: Prior reviews of esophageal perforation with delayed recognition have reported mortality rates as high as 66%. We performed a retrospective review of patients with nonmalignant esophageal perforation to assess the outcome of current management techniques. PATIENTS AND METHODS: Charts were reviewed of all patients who were treated for nonmalignant esophageal perforation between 1980 and 1993. They were 23 men and 10 women, mean age 49 +/- 3 years, 19 of whom were diagnosed early (< or = 24 hours) and 14 of whom were diagnosed late (> 24 hours). RESULTS: Perforations were due to instrumentation (16), operative injury (7), spontaneous rupture (4), trauma (4), and other causes (2). Pre-existing esophageal disease was identified in 23 patients (70%), including achalasia (9), stricture (7), varices (5), and other (2). Treatment included closure and fundoplication or muscle wrap (10), closure with or without pleural flap (7), resection only (7), resection and reconstruction (3), drainage only (4), and observation (2). Nonfatal complications included empyema (4), arrhythmia (3), persistent leak following attempted closure (2), and other (5). They occurred in 50% of both the early and late diagnosis groups and were of comparable severity in both. The overall mortality was 9% (3/33). Causes of death were sepsis (1) and multisystem organ failure (2). Mortality was 5% (1/19) in patients diagnosed early and 14% (2/14) of those diagnosed late. CONCLUSIONS: Current mortality rates in nonmalignant esophageal perforation are improved compared to previously published rates of 19% for all patients with the condition, 9% following early and 29% following late diagnosis (47 patients overall). We conclude that, despite a high incidence of associated complications, the survival rate following nonmalignant esophageal perforation is improving and the impact of delayed recognition is decreasing.

Adolescent↗

PubMed1995

Optimizing selection of patients for major lung resection.

OBJECTIVES: It is not known whether a normal diffusing capacity for carbon monoxide permits safe lung resection in patients with marginal spirometric values, or whether normal spirometric values negate the adverse effects of a low diffusing capacity. The purposes of this study were (1) to determine the best predictors of morbidity and mortality and (2) to assess whether interactions exist between diffusing capacity and spirometry that help estimate outcome after major lung resection. DESIGN: A retrospective analysis of 376 patients who underwent lung resection was performed. Three hundred three had lung cancer and 73 had other disease. Two hundred eighty-four underwent lobectomy/bilobectomy and 92 had pneumonectomy. We assessed the relationship of 23 preoperative variables to 18 postoperative events classified into categories as pulmonary or cardiac complications, overall morbidity, and operative mortality. RESULTS: The best single predictor of complications was the percent predicted postoperative diffusing capacity. The incidences of pulmonary and cardiac complications, morbidity, and mortality were inversely related to predicted postoperative diffusing capacity percent (p < 0.004 for each). Multivariate logistic regression analyses identified only predicted postoperative diffusing capacity percent and age as significant independent predictors of pulmonary complications, morbidity, and death, and these with prior myocardial infarction predicted cardiac complications. There were no interactions between percent predicted postoperative forced expiratory volume in 1 second and predicted postoperative diffusing capacity percent in estimating risks of complications. CONCLUSION: Predicted postoperative diffusing capacity percent is the strongest single predictor of risk of complications and mortality after lung resection. There is little interrelationship of predicted postoperative diffusing capacity percent and predicted postoperative forced expiratory volume in 1 second, indicating that these values should be assessed independently in estimating operative risk.

Female↗

PubMed1994

Modulation of lymphatic spontaneous contractions by EDRF.

Mesenteric lymph vessels exhibit spontaneous contractions that are critical in lymph fluid propulsion. We hypothesized that endothelium-derived relaxing factor (EDRF), recently identified as being released by lymph vessels, regulates contractile activity in mesenteric lymph vessels. Porcine mesenteric lymph vessel rings in vitro were administered either prostaglandin F2 alpha (PGF2 alpha; 10(-6) M), which increases contractile activity, NG-monomethyl-L-arginine (L-NMMA; 10(-4) M), which blocks EDRF production, or PGF2 alpha + L-NMMA, while paired control vessel rings remained in Krebs buffer alone. Vessel segments stimulated with PGF2 alpha exhibited repetitive contractions with more regular rhythm and uniform morphology than control segments and significantly greater frequency, amplitude, and trough and active tensions. Inhibition of EDRF production significantly enhanced the frequency (3.9 +/- 0.5 vs 2.1 +/- 0.4 min-1) and amplitude (555 +/- 42 vs 378 +/- 62 mg) of basal spontaneous contractions compared to controls and appeared to elicit more uniform contractions with respect to rhythm and morphology. PGF2 alpha-stimulated vessels pretreated with L-NMMA demonstrated uniform contractions with significant increases in contraction frequency (6.3 +/- 0.7 vs 2.4 vs 0.9 min-1), amplitude (846 +/- 120 vs 495 +/- 99 mg), trough tension (738 +/- 146 vs -6 +/- 32 mg), and active tension (1584 +/- 192 vs 489 +/- 111 mg) compared to controls (P < 0.05 for each). The effects of L-NMMA on unstimulated vessels were reversed by the addition of L-arginine but not by D-arginine (10(-4) M for each).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Characterization of contractile properties of porcine mesenteric and tracheobronchial lymphatic smooth muscle.

We performed morphometric and length-tension analyses comparing mesenteric and tracheobronchial lymph vessel segments to determine the potential of the latter tissue to regulate pulmonary and mediastinal lymph flow via alterations in smooth muscle tone. Fresh porcine lymph vessel rings were prepared for 1) in vitro assessment of length-tension relationships and 2) histologic preparation and measurement of smooth muscle cross-sectional area (SMA). Mesenteric and tracheobronchial optimal vessel ring lengths were 3.1 +/- 0.2 and 3.5 +/- 0.2 mm, and maximum active tensions were 1518 +/- 25 and 1703 +/- 162 mg. Smooth muscle formed indistinct layers in each tissue, and only 30% of the smooth muscle was oriented circumferentially. Stress generated by the circular smooth muscle was similar to that generated by other types of vascular smooth muscle. In 75% of mesenteric vessel rings spontaneous contractions were observed that had a mean contraction frequency of 1.7 +/- 0.2 min-1 and a mean contraction amplitude of 349 +/- 35 mg, while only 40% of tracheobronchial vessels exhibited spontaneous contractions (p < 0.001) that had a mean frequency of 0.6 +/- 0.2 min-1 (p = 0.0021) and a mean contraction amplitude of 118 +/- 10 mg (p < 0.0001). We conclude that tracheobronchial lymphatic vascular smooth muscle is capable of developing stress similar to that generated by mesenteric lymph vessels, and that spontaneous rhythmic contractile activity is qualitatively and quantitatively different in tracheobronchial than in mesenteric porcine lymph vessels. The data suggest that tracheobronchial lymph vessels are capable of regulating pulmonary and mediastinal lymph flow through intrinsic mechanisms. Such regulation may occur by alterations in vascular resistance rather than via spontaneous pumping activity.

Animals↗

PubMed1993

Esophagectomy in the septuagenarian.

As the population continues to age, older patients are being referred for thoracic surgical procedures with increasing frequency. From 1985 through 1992, 38 patients (32 men, 6 women) 70 years of age or older underwent esophagectomy for primary esophageal carcinoma. Histologic findings included adenocarcinoma in 28 (74%) and squamous carcinoma in 10 (26%). Patients suffered dysphagia for a mean of 3.8 months (range, 0 to 30 months) and had a mean weight loss of 5.8 kg (range, 0 to 22 kg). The tumors ranged from 1 to 14 cm in length and averaged 4.7 cm. Preoperative chemotherapy and radiation therapy were administered in 11 patients (46%). Clinical staging suggested all patients were curable, and esophagectomy was performed in a transthoracic fashion in 27 (71%) and from a transhiatal approach in 11 (29%). Cervical anastomoses were undertaken in 16 patients (42%). The mean blood loss was 1,165 mL and ranged from 500 to 4,000 mL. The mean number of transfused units was 2.3 (range 0 to 8 U). Overall operative mortality was 18% (7 of 38). Major morbidity included pneumonia in 11 (29%), anastomotic leak in 4 (11%), chylothorax in 4 (11%), pulmonary embolus in 3 (8%), and stroke and myocardial infarction in 1 patient each (3%). Three patients have been cured of their esophageal cancer with survivals of 65, 70, and 72 months and an additional 7 patients are still alive. Three patients (8%) have been lost to follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

PubMedDate not supplied

Mortality after esophagectomy: risk factor analysis.

Esophageal resection is associated with a high incidence of operative mortality, suggesting the need for predictors of operative risk. A retrospective analysis was performed for esophagectomy patients using univariate and multivariate analyses; relative risks (RR) were calculated. Of the 269 patients, 35 (13%) died. The optimal model for the preoperative prediction of risk of mortality was defined by age (p = 0.001; RR = 2.6) and performance status (p = 0.04; RR = 1.9). Delimiting the data pool using a calculated risk of 0.2 accurately identified outcomes in 79% of patients and predicted 41% of deaths. The optimal model for the overall prediction of risk of mortality was defined by age (p = 0.001; RR = 3.9), intraoperative blood loss (p < 0.001; RR = 1.7), pulmonary complications (p = 0.002; RR = 6.6), and the need for inotropic support (p = 0.003; RR = 10.2). The individual risk of mortality after esophagectomy can be predicted preoperatively with a model based on patient age and performance status. The findings underscore the importance of preoperative evaluation of cardiopulmonary function, meticulous operative technique, and aggressive respiratory care in the management of the esophagectomy patient.

Adolescent↗

PubMedDate not supplied

Outcome after failed initial therapy for rupture of the esophagus or intrathoracic stomach.

Survival after rupture of the esophagus or intrathoracic stomach is improving, but continued leakage after initial therapy remains a problem. We retrospectively reviewed patients with rupture of the esophagus or intrathoracic stomach to determine the prevalence of continued leakage after initial therapy and how this complication affects outcome. Our review included 58 patients, 38 (66%) of whom had preexisting esophageal disease. The etiology of perforation was spontaneous rupture in 17, penetrating trauma in four, and iatrogenic injury in 35; two patients had perforation from other causes. Initial therapy consisted of drainage in eight, primary repair in 24, resection in 18, bypass in two, and observation in six. The overall mortality rate was 12% (7 of 58 patients) and continuing leaks were identified in 21% (12 of 58 patients). These leaks were unrelated to patient age, existence of prior disease, or delay in therapy but were more common after initial treatment by primary repair with or without pleural flap coverage compared to other management strategies (6 of 9 vs. 6 of 49; P < 0.001). Salvage therapy with survival was possible in 10 (83%) of 12 patients by means of esophagectomy in four, exclusion in one, drainage in two, or observation in three. Continuing leaks can be avoided by providing soft tissue coverage other than pleura over a primary repair and by not leaving an intrathoracic esophageal stump. Aggressive management of continuing leaks results in survival in more than 80% of patients.

Adolescent↗