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Biomedical subjects

M S Allen

Publications and source records attributed to M S Allen.

At least 91 records · Page 5Linked to original sources
PubMed1996

Postoperative chylothorax.

Between July 1987 and May 1995, 11,315 patients underwent general thoracic surgical procedures at our institution. In 47 of these patients (0.42%), postoperative chylothorax developed. There were 32 men and 15 women with a median age of 65 years (range 21 to 88 years). Initial operation was for esophageal disease in 27 patients, pulmonary disease in 13, mediastinal mass in six, and thoracic aortic aneurysm in one. All patients were initially treated with hyperalimentation, cessation of oral intake, medium chain triglyceride diet, or a combination. Nonoperative therapy was successful in 13 cases (27.7%), and oral intake was resumed a median of 7 days later (range 2 to 15 days). Reoperation was required in the remaining 34 cases. The reoperation rate varied according to the type of initial operation. Twenty-four of the 27 patients (88.9%) who had undergone an esophageal operation required reoperation, versus only five of 13 patients (38.5%) who had undergone pulmonary resection (p < 0.001). Lymphangiography was performed in 16 patients and identified the site of the leak in 13. The thoracic duct was ligated in 32 of the 34 patients who required reoperation (94%). The remaining two patients were treated with mechanical pleurodesis and fibrin glue. Reoperation was successful in 31 of the 34 patients (91.2%). The single death among the 47 patients (2.1%) occurred in the reoperated group. Complications occurred in 18 patients (38.3%). Factors that predicted the need for reoperation were initial esophageal operation and average daily postoperative drainage greater than 1000 ml/day for 7 days. We conclude that postoperative chylothorax is an infrequent complication. Some cases can be managed without operation; however, we recommend early reoperation when drainage is greater than 1000 ml/day or if the chylous fistula occurs after an esophageal operation. The fistula can usually be controlled by ligation of the thoracic duct.

Adult↗
PubMed1996

Barretts's esophagus: does an antireflux procedure reduce the need for endoscopic surveillance?

Barrett's esophagus, a premalignant condition associated with chronic gastroesophageal reflux, carries an approximate 40-fold increase in the incidence of adenocarcinoma. Between 1975 and 1994, 113 patients with Barrett's esophagus underwent antireflux procedures at the Mayo Clinic. The antireflux procedure was performed more than 3 months after the diagnosis of Barrett's disease in 39 patients (34.5%) and during the initial preoperative evaluation in 74 (65.5%). Uncut Collis-Nissen fundoplication was performed in 69 patients (61.1%), Nissen fundoplication was performed in 16 (14.2%), cut Collis-Nissen fundoplication was performed in 12 (10.6%), Belsey repair was performed in nine (8.0%), Collis-Belsey repair was performed in six (5.3%), and Nissen fundoplication with an anterior gastropexy was performed in one (0.9%). There was one operative death (0.9% mortality). Morbidity occurred in 41 patients (36.3%), including cardiac arrhythmia in eight (7.0%), pneumonia in six (5.3%), empyema in five (4.4%), hemorrhage in four (3.6%), myocardial infarction in two (1.8%), and wound dehiscence, wound infection, perforated duodenal ulcer, and postoperative leak in one each (0.9%). Median follow-up for the 112 survivors of operation was 6.5 years (range 4 months to 18.2 years). Excellent or good alleviation of symptoms was obtained in 92 patients (82.2%). Ninety-nine patients (88.4%) are currently alive and 13 (11.6%) have died. Three patients (2.7%) subsequently had adenocarcinoma of the esophagus after the antireflux procedure at 13, 25, and 39 months; two of these died of cancer. The incidence of esophageal carcinoma in this select group of patients was one in 273.8 patient-years of follow-up. We conclude that although antireflux procedures in patients with Barrett's esophagus result in long-term control of reflux symptoms, the possibility of esophageal cancer still exists. Endoscopic surveillance should therefore be recommended.

Adenocarcinoma↗
PubMed1996

Physical constraints on voluntary intake of forages by ruminants.

Voluntary dry matter intake (VDMI) of forages by ruminants may be limited by distention resulting from restricted flow of digesta through the gastrointestinal tract. An animal's capacity for fill depends on the weight and volume of digesta that causes distention and the flow rate of digesta from the organ in which distention occurs. The reticulorumen is generally regarded as the site in the gastrointestinal tract for which distention limits VDMI with high-fill diets, although evidence suggests that distention of the abomasum may also limit VDMI. Linear decreases in VDMI have been noted with increasing amounts of inert fill inserted into the reticulorumen, but results have not been consistent across several experiments. Reduction in VDMI depends on the extent to which intake is limited by fill before insertion of inert fill; hence animals with high energy requirements consuming relatively low-energy, high-fill diets are affected to the greatest extent. Because NDF generally ferments and passes from the reticulorumen more slowly than other dietary constituents, it has a greater filling effect over time than non-fibrous feed components and has been found to be the best single chemical predictor of VDMI. However, many other factors affect fill, including particle size, chewing frequency and effectiveness, particle fragility, indigestible NDF fraction, rate of fermentation of the potentially digestible NDF, and characteristics of reticular contractions. These factors are only partially accounted for in models that have been developed to predict VDMI. Increased accuracy of prediction of VDMI is expected as models continue to evolve.

Animals↗
PubMed1996

Enhanced intake and production of cows offered ensiled alfalfa with higher neutral detergent fiber digestibility.

The objective of this study was to determine the effect of forage fiber digestibility as part of a total mixed diet on intake and production of cows with intakes that were likely limited by rumen fill, using treatments that were not confounded by fiber source, concentrate, or ratio of forage to concentrate. Two alfalfa silages with similar NDF concentrations (40%) but different NDF digestibilities (40 vs. 45% after 24 h of in vitro fermentation) were harvested, mixed with concentrate to achieve diets containing 35% NDF, and offered to 12 multiparous cows (13 DIM) in a two-period balanced crossover design. Samples taken during silage feeding revealed that diets differed in both NDF digestibility (3 percentage units) and NDF content (1.8 percentage units), making interpretation of results difficult. Nonetheless, milk production (36.3 vs. 38.2 kg/d) and DMI (19.4 vs. 20.4 kg/d) were significantly higher with the higher NDF digestibility diet. Apparent in vivo DM and NDF digestibilities, total rumen VFA after feeding, and molar percentage of propionate were also higher with this diet. Equal NDF intake between diets suggested that higher DMI was due to the lower NDF content in the more digestible NDF diet. Higher NDF digestibility might also increase DMI; further experimentation is necessary with larger unconfounded differences in fiber digestibility at the time of feeding.

Animals↗
PubMed1996

Lasalocid and particle size of corn grain for dairy cows in early lactation. 1. Effect on performance, serum metabolites, and nutrient digestibility.

The effects were examined of corn grain particle size and the ionophore lasalocid on performance, blood parameters, and nutrient digestibility of early lactation cows. Smaller corn particle size was expected to result in faster rate of digestion and ruminal fermentation of starch. Eight multiparous and 4 primiparous cows in early lactation were fed diets (44% forage) with cracked or ground, dried shelled corn grain and with or without lasalocid (360.mg/d per cow). The experiment was a replicated (n = 3) 4 x 4 Latin square design with 21-d periods and a 2 x 2 factorial arrangement of treatments. Lasalocid tended to improve DMI. Lasalocid and ground corn decreased body condition loss and milk fat and increased milk protein. Ground corn tended to increase milk yield but had no effect on 4% FCM, lactose, and BW. For all cows, milk yield, 4% FCM, lactose, and BW were unaffected by lasalocid; however, subsequent analysis of individual squares revealed that milk yield of primiparous cows increased with lasalocid. Ground corn increased total tract starch digestibility and decreased NDF digestibility. Interactions between lasalocid and particle size of corn grain were observed only for change in serum insulin concentration before and after meals.

Animal Nutritional Physiological Phenomena↗
PubMed1996

Lasalocid and particle size of corn grain for dairy cows in early lactation. 2. Effect on ruminal measurements and feeding behavior.

The effects particle size of corn grain and the ionophore lasalocid on ruminal fermentation and feeding behavior of early lactation cows were examined. Eight multiparous and 4 primiparous cows in early lactation were fed diets (44% forage) with cracked or ground dried shelled corn grain and with or without lasalocid (360 mg/d per cow). The experiment was a replicated (n = 3) 4 x 4 Latin square design with 21-d periods and a 2 x 2 factorial arrangement of treatments. Ground corn decreased ruminal turnover time of starch, did not affect ruminal lactate concentrations, increased propionate, decreased the ratio of acetate to propionate, and decreased branched-chain fatty acids. The range of ruminal pH within a day increased with ground corn, but mean pH was unaffected by treatment. Lasalocid increased lactate concentrations and did not affect the ratio of acetate to propionate. Lasalocid increased total time spent ruminating, and ground corn decreased ruminal contractions. Lasalocid tended to increase water intake, and ground corn increased water intake. Interactions of lasalocid and particle size of the corn grain were observed for ruminal turnover time of starch and NDF, and ruminal pool size of acetate and total VFA.

Acetates↗
PubMed1996

Video-assisted thoracic surgical procedures: the Mayo experience.

OBJECTIVE: To describe an initial 3-year experience with video-assisted thoracic surgical procedures (VATS) at Mayo Clinic Rochester. DESIGN: We review the cumulative data on 771 VATS performed between June 1, 1991, and May 31, 1994, and assess the applications for this technique. MATERIAL AND METHODS: The indications for VATS, our techniques used, and the associated mortality and morbidity are summarized. In addition, the frequency of conversion of VATS to open procedures and the reasons for choosing this strategy are discussed. RESULTS: The 771 study patients (401 male and 370 female patients) had a median age of 62 years (range, 7 to 96). For all VATS. we used one-lung general anesthesia, without carbon dioxide insufflation. Indications for performing VATS were a pulmonary nodule in 333 patients, pleural effusion in 208, pulmonary infiltrate in 117, pneumothorax in 51, mediastinal mass in 22, pleural mass in 17, air leak in 13, and other in 10. The procedure was a wedge excision in 352 patients, examination of the pleural cavity in 128, pleural biopsy in 86, talc pleurodesis in 85, wedge excision and mechanical pleurodesis in 46, decortication in 27, excision of a mediastinal mass in 12, sympathectomy in 4, and other in 16. The rate of conversion of VATS to thoracotomy was 33.1% and did not change throughout the period of the study. The most common reasons for conversion were to complete a resection of a malignant lesion or to remove a deep nodule. The overall operative mortality was 1.9%. Complications occurred in 43 patients (8.3%) who underwent VATS without conversion to an open procedure and included prolonged air leak in 14, respiratory failure in 8, pneumothorax in 6, and atrial fibrillation in 5. The median hospitalization was 5 days (range, 1 to 104). CONCLUSION: VATS is safe and useful for selected thoracic conditions. We favor conversion to thoracotomy when curative resection of a malignant lesion is intended.

Adolescent↗
PubMed1996

Lung resection in patients with compromised pulmonary function.

BACKGROUND: Some patients are denied curative pulmonary resection for lung carcinoma because of pulmonary insufficiency. To identify factors that affect postoperative morbidity and mortality, we reviewed 85 consecutive patients (53 men and 32 women) with a preoperative forced expiratory volume in 1 second of less than 1.2 L who underwent pulmonary resection for lung cancer between January 1986 and December 1990. METHODS: Median age was 70 years (range, 49 to 82 years). Sixty patients (71%) had been previously denied operation because of pulmonary insufficiency. Preoperative pulmonary function demonstrated a median preoperative forced expiratory volume in 1 second of 1.0 L (44% of predicted normal; range, 0.5 to 1.2 L) and a diffusing capacity of the lung for carbon monoxide of 60% of predicted normal (range, 22% to 104%). RESULTS: Pneumonectomy was done in 6 patients (7.1%), bilobectomy in 6 (7.1%), lobectomy in 38 (44.7%), segmentectomy in 12 (14.1%), and wedge excision in 29 (27.1%). The median predicted postoperative forced expiratory volume in 1 second was 0.83 L (34% of predicted normal; range, 0.45 to 1.14 L), and the median predicted postoperative diffusing capacity of the lung for carbon monoxide was 48% of predicted normal (range, 19% to 87%). Seventy-two patients (85%) received postoperative epidural analgesia. Median hospitalization was 15 days (range, 5 to 66 days). Operative mortality was 2.4%, and complications occurred in 49%. We did not identify any factors that predicted postoperative morbidity and mortality. Median follow-up was 3.2 years (range, 0.2 to 9 years). Seven patients (8%) required supplemental home oxygen. A predicted postoperative percent forced expiratory volume in 1 second less than 43% correlated with the need for home oxygen (p < 0.05). Overall 5-year survival was 44.0%. Survival for stage I cancer was 54.2%; stage II, 33.1%; and stage IIIa, 21.3%. CONCLUSIONS: We conclude that some patients with lung cancer and compromised pulmonary function can safely undergo pulmonary resection if selected appropriately.

Aged↗
PubMed1996

Management of postpneumonectomy empyema and bronchopleural fistula.

Postpneumonectomy empyema with or without fistula is a serious complication. Management includes drainage, antibiotherapy, debridement closure of the bronchopleural fistula when present, and obliteration of the residual pleural space. Excellent results can be obtained in most patients using the Clagett procedure and its modification. A detailed description of each step of the surgical treatment of postpneumonectomy empyema and associated bronchopleural fistula is provided.

Bronchial Fistula↗
PubMed1996

Surgical anatomy of the trachea.

A clear understanding of tracheal anatomy is a fundamental building block for surgical procedures. Surprisingly, information about the surgical anatomy of the trachea is scant. This article describes the anatomy of the trachea and highlights how these anatomic facts affect surgical procedures performed on the trachea.

Humans↗
PubMed1995

Esophageal replacement by colon interposition.

Between 1985 and 1993, 32 patients (24 male and 8 female) underwent colon interposition for replacement of the esophagus at the Mayo Clinic. Median age was 58.5 years (range, 1 to 79 years). The colon was used because of an inadequate stomach in 27 patients (84%) and as the conduit of choice in 5 (16%). Esophageal cancer was present in 15 patients (47%). The left colon was used in 20 patients (63%) and the right, in 12 (38%). The colon was placed substernally in 19 patients (59%) and in the esophageal bed in 13 (41%). The operative mortality was 9%; cause of death was ischemic necrosis of right colon conduits in 2 patients and adult respiratory distress syndrome in 1 patient. Major complications occurred in 4 additional patients and included ischemic colitis of a right colon conduit, Roux-en-Y limb obstruction, chylothorax, and an anastomotic leak. Follow-up was complete for all patients and ranged from 15 months to 7 years (median follow-up, 2.3 years). Eleven patients died during follow-up. The cause of death was metastatic esophageal cancer in 9 patients, myocardial infarction in 1 patient, and respiratory failure in 1 patient. At last follow-up, 26 of the 29 operative survivors had little or no difficulty eating. Two patients had dumping symptoms, and 1 patient had severe dysphagia. Seven patients required dilation of the esophagocolonic anastomosis. We conclude that colon interposition for esophageal replacement provides acceptable long-term function; however, early morbidity and mortality are considerable.

Adolescent↗
PubMed1995

Esophageal resection for recurrent achalasia.

BACKGROUND: This study examined esophageal resection as treatment for recurrence or treatment complications of achalasia. METHODS: From 1976 through 1992, 37 patients (20 men and 17 women) underwent esophageal resection after initial surgical treatment for achalasia. The median age was 56 years (range, 19 to 84 years). Initial surgical treatment consisted of modified Heller myotomy in 28 patients, combined myotomy and antireflux procedure in 6, and antireflux procedure alone in 3. Twenty-six patients required an additional surgical procedure before esophageal resection (70.3%). Indication for esophageal resection was obstructive symptoms in 30 patients, cancer in 3, bleeding in 2, and perforation during dilation in 2. Reconstruction was established with the stomach in 26 patients, colon in 6, and small bowel in 5. Anastomosis was at the cervical level in 20 patients (54.1%) and intrathoracic in 17 (45.9%). RESULTS: There were two operative deaths (5.4%), both caused by intraoperative hemorrhage during transhiatal resection. Twelve patients (32.4%) had complications, which included cardiac dysrhythmia in 3, cervical anastomotic leak in 2, transient vocal cord paralysis in 2, pneumonia in 2, pulmonary embolus in 2, and reexploration for bleeding in 1. Follow-up was complete in all patients and ranged from 1.4 to 16 years (median, 6.3 years). Excellent or good long-term functional results were present in 32 patients (91.4%). CONCLUSIONS: Esophageal resection provides reasonable long-term functional results in patients with recurrence or treatment complications of achalasia. In our experience, transhiatal resection is associated with increased morbidity and mortality.

Adult↗
PubMed1995

Pathologic comparison of video-assisted thoracic surgical lung biopsy with traditional open lung biopsy.

Video-assisted thoracic surgical lung biopsy is an alternative to traditional open lung biopsy for diagnosis in patients with pleuropulmonary diseases. Between January 7, 1991, and August 3, 1993, 71 consecutive patients had video-assisted thoracic surgical lung biopsy and 42 patients had traditional open lung biopsy. A specific histologic diagnosis that correlated with the clinical findings was sought in each case and the yield was compared between the two groups. Procedure-related artifactual changes were also evaluated; the extent of traumatic hemorrhage and neutrophil margination as a result of tissue manipulation was significantly greater for patients in the video-assisted thoracic surgical lung biopsy group than for those in the open lung biopsy group, but the changes were generally minor and did not affect diagnostic yield. Complications developed in 11 (15%) of 71 patients in the video-assisted thoracic surgical lung biopsy group including 5 patients with prolonged air leakage (more than 10 days); 2 with pneumonia; and 1 each with bleeding, late pneumothorax necessitating readmission, mucus plug necessitating bronchoscopy, and a hypoxic episode necessitating mechanical ventilation. On the other hand, 7 (17%) of 42 patients in the open lung biopsy group had complications including 4 patients with prolonged air leakage (more than 10 days) and 3 with pneumonia. There were 6 (8%) operative deaths in patients who had video-assisted thoracic surgical lung biopsy and 7 (17%) in the open lung biopsy group; all had preoperative respiratory failure. We conclude that video-assisted thoracic surgical lung biopsy is an acceptable alternative to open lung biopsy for diagnosis of pulmonary infiltrates or indeterminate nodules.

Adult↗
PubMed1995

Sullivan's closet: a reappraisal of Harry Stack Sullivan's life and his pioneering role in American psychiatry.

Although Harry Stack Sullivan (1892-1949) was one of the foremost figures in American psychiatry, much about his personal life remains obscure, this despite a 1983 biography by Helen Swick Perry that hints at, but ultimately denies, his homosexuality. Rumors about Sullivan's homosexuality, fueled by his living for 22 years with another man, his "foster son," were widespread during his life. Interviews I conducted with many of his contemporaries--colleagues, students, and friends--yielded sharply conflicting stories, but do substantiate that Sullivan was, for his time, openly homosexual. In addition, I discovered that Sullivan's experimental treatment ward for schizophrenics at the Sheppard-Pratt Hospital in Baltimore, which he ran from 1925 to 1929, and which brought him worldwide attention, was more daring and radical than his biographer has written. Sullivan was, perhaps, the first to use para-professionals to treat hospitalized schizophrenics, an approach that was considered revolutionary in the 1920s. What was not widely known, though, was that almost all the men on the all-male ward during those five years, both the ward attendants, whom Sullivan selected and trained, and the patients, were gay.

History, 19th Century↗
PubMed1995

Characteristics of plant cell walls affecting intake and digestibility of forages by ruminants.

Even under the intensive concentrate feeding systems of ruminant animal production in the United States, forages continue to represent the single most important feed resource. Cell-wall concentration and digestibility limit the intake potential and energy availability of forage crops in beef and dairy production. Identification of cell-wall characteristics that should be targets of genetic modification is required if plant breeders and molecular biologists are to successfully improve forages for livestock feeding. As the forage plant cell develops, phenolic acids and lignin are deposited in the maturing cell wall in specific structural conformations, and in a strict developmental sequence. Lignin is the key element that limits cell-wall digestibility, but cross-linkage of lignin and wall polysaccharides by ferulic acid bridges may be a prerequisite for lignin to exert its affect. Lignin composition and p-coumaric acid in the wall are less likely to affect digestibility. Voluntary intake of forages is a critical determinant of animal performance and cell-wall concentration is negatively related to intake of ruminants consuming high-forage diets. Cell walls affect intake by contributing to ruminal fill. A simple model of cell-wall digestion and passage in which ruminal fill is a function of rates of digestion and passage, as well as the indigestible fraction of the cell-wall indicates that cell-wall concentration and rate of passage are the most critical parameters determining ruminal fill. Plant factors that affect rate of passage include those that affect particle size reduction by chewing and those that affect particle buoyancy in the rumen. The latter is primarily affected by 1) the ability of the particulate matter to retain gases, which is probably related to plant anatomy and rate of digestion of the plant tissue, and 2) the rate at which the gas is produced, which is affected by the potentially digestible fraction of the particulate matter and the rate of digestion of this fraction. Increasing rate of digestion should increase rate of passage by diminishing the gas produced and increasing density over time. A reduction in the indigestible cell-wall fraction is beneficial because this will decrease fill and increase digestibility. Animal production and economic benefits from reduced cell-wall concentration and increased digestibility are significant. Because of the high cell-wall concentration and large digestible cell-wall fraction of grasses, reduction in cell-wall concentration would probably be of greater value than improving digestibility in these species. Legumes represent the opposite situation and may benefit more from improvements in the digestibility of their cell walls.

Animal Feed↗
PubMed1995

Intake limitations, feeding behavior, and rumen function of cows challenged with rumen fill from dietary fiber or inert bulk.

Twelve multiparous, rumen-cannulated cows (17 DIM) were fed 25 or 35% NDF diets without or with added rumen-inert bulk as water-filled plastic containers (500 ml each) within three 4 x 4 Latin squares (21-d periods). Added bulk equaled 25% of pretrial rumen volume for each cow. Objectives were to challenge cows with rumen fill in the form of dietary NDF and inert bulk to determine whether bulk affects intake similarly for diets of different NDF content or whether changes in behavior or rumen function allow cows to adapt to higher fill. Inert bulk had no effect on DMI for cows fed 25% NDF but decreased DMI for cows fed 35% NDF (18.7 vs. 16.6 kg/d). Volume of rumen digesta plus inert bulk, 102 L, was similar for 35% NDF treatments regardless of presence or absence inert bulk. Additional NDF or inert bulk increased the number of ruminating bouts per day, chewing time per unit of DMI or NDF intake, frequency of reticular contractions during rumination, and fractional passage rate of NDF from the rumen. Although these changes may help to alleviate fill, they were insufficient to maintain intake under conditions of high fill. Intake by cows receiving high fiber diets can be limited by reticulorumen capacity. Future study is required to determine the effect of rumen fiber digestion, fiber particle size, and animal characteristics on fill-limited intake.

Animal Feed↗
PubMed1995

Effect of plant maturity and preservation method on in vitro protein degradation of forages.

The influence of maturity and method of conservation on protein degradation was determined for four different forage species. Alfalfa, smooth bromegrass, and reed canarygrass were harvested at three maturities, and whole plant corn was harvested at two maturities. Samples of each forage were freeze-dried or wilted and then ensiled in mini silos at two DM contents. Additional samples of all forages except corn were field-dried to hay. Ground sample was incubated for 0, 2, and 24 h with crude enzyme extract from ruminal contents. Degraded protein as a percentage of total CP was determined as the amount of protein that was soluble in TCA (80 g/L) after degradation. Increased maturity resulted in lower protein degradation for alfalfa, bromegrass, and canarygrass. For example, the most mature alfalfa or bromegrass, respectively, had 77 or 63% as much N that was soluble in TCA after 2 h of incubation with ruminal enzyme than the least mature forage of the same species. Although protein degradation was higher for ensiled than for dried forage, silage DM content had no consistent effect. Freeze-dried material generally had less degraded protein than hay, but protein degradation of bromegrass at 24 h was lower for hay than for freeze-dried samples. Protein degradation of forages was highly variable and depended on plant maturity and conservation method.

Animal Feed↗