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Biomedical subjects

J M Henderson

Publications and source records attributed to J M Henderson.

At least 19 recordsLinked to original sources
PubMed1995

The prevalence of coronary artery disease in liver transplant candidates over age 50.

The prevalence of angiographically proven coronary artery disease (CAD) in adults with end-stage liver disease who undergo evaluation for liver transplantation is unknown; also it is unclear if cholestatic liver disease represents an independent risk factor. Patients with end-stage liver disease over age 50 having liver transplantation were studied using coronary angiography. Arterial stenosis was graded as normal, mild (< 30%), moderate (30 to 70%), or severe (> 70%). Risk factors for CAD were also assessed (male sex, smoking, hypertension, diabetes, family history of premature heart disease). Complications related to the angiography and decision making based on the findings were recorded. Thirty seven patients (23 females) with a median age of 61 years (range 50 to 71) underwent angiography. Thirteen patients (35.1%) had cholestatic liver disease. Thirty patients had no history of heart disease. The overall prevalence of severe coronary artery disease was 16.2% (95% confidence interval [CI] = 6.2% to 32.0%). No association was detected between CAD and cholestatic liver disease (P = 0.72). After eliminating seven patients with a prior history of angina (n = 1), myocardial infarction (n = 1), or coronary revascularization (n = 5), the frequency of moderate or severe CAD was 13.3% (95% CI = 3.8% to 30.7%). No association was detected between unsuspected CAD and cholestatic liver disease (P = 0.61). Diabetes was the most important risk factor for moderate or severe disease (P = 0.01). Patients without risk factors had significantly less CAD than the group as a whole regardless of the liver disease type (P = 0.02). Two patients experienced transient renal insufficiency after the angiography. Three patients with severe CAD were denied transplantation. We conclude that CAD represents a significant problem in patients over age 50 undergoing liver transplant evaluation. Cholestatic liver disease was not associated with a significantly higher prevalence of moderate or severe CAD in our population. Diabetes was the most predictive risk factor, and those without risk factors do not require extensive preoperative cardiac evaluation.

Age Factors↗
PubMed1995

Single-day, divided-dose oral sodium phosphate laxative versus intestinal lavage as preparation for colonoscopy: efficacy and patient tolerance.

Polyethylene glycol-electrolyte lavage solutions are widely used to prepare the colon for colonoscopy. Unfortunately, some patients find this preparation difficult to complete. Recent studies of a sodium phosphate-based laxative have shown both good patient tolerance and good bowel preparation. In these studies, the laxative has generally been prescribed in two doses, with the second dose taken early the morning of colonoscopy. Because the morning dose is inconvenient for many patients, we compared giving a common polyethylene glycol-based electrolyte lavage solution the day before colonoscopy with our method of giving both doses of sodium phosphate-based laxative the day before colonoscopy: one dose at 4 PM and the second dose at 8 PM. We judged efficacy by an assessment of residual liquid and fecal matter in the colon and judged tolerance by the results of a symptom questionnaire completed by each patient immediately before the procedure. Our results in more than 200 patients showed similar efficacy ratings and similar symptom scores for both preparations, but patients rated the sodium phosphate-based preparation as easier to tolerate. In conclusion, in selected patients this new dosing method for sodium phosphate is preferable to large-volume, whole-gut lavage solutions.

Administration, Oral↗
PubMed1995

Case report: fulminant Kaposi's sarcoma after orthotopic liver transplantation.

Fulminant multicentric Kaposi's sarcoma developed in an American-born HIV-negative patient 8 months after orthotopic liver transplantation. Despite its rarity in liver transplantation, Kaposi's sarcoma should be considered in the differential diagnosis in hepatic allograft recipients presenting with rapidly growing cutaneous or polylymphadenopathic lesions.

Autopsy↗
PubMed1995

Fifty years of surgery for portal hypertension at the Cleveland Clinic Foundation. Lessons and prospects.

OBJECTIVE: The 50-year experience with surgery for the treatment of portal hypertension and bleeding varices at the Cleveland Clinic is reviewed. SUMMARY BACKGROUND DATA: A variety of procedures have been used to treat bleeding varices during the past 50 years. These include transesophageal ligation of varices or devascularization of the esophagus and stomach with splenectomy; portal-systemic (total) shunts; distal splenorenal (selective) shunts; endoscopic sclerotherapy; transjugular intrahepatic portal-systemic shunts; and liver transplantation. METHODS: Our experience with these procedures is reviewed in four time periods: 1946 to 1964, 1965 to 1980, 1980 to 1990, and 1990 to 1994. RESULTS: Our use of these procedures has changed as experience and new techniques for managing portal hypertension have evolved. Most ligation--devascularization--splenectomy procedures were performed before 1980; they provide excellent results in patients with normal livers and extrahepatic portal venous obstruction, but a major complication (40-50%) is rebleeding. Total shunts were performed most frequently before 1980; with patient selection, operative mortality was reduced to 8%, control of bleeding was achieved in more than 90%, but the incidence of encephalopathy was high (30%). Selective shunts provide almost equal protection from rebleeding with less post-shunt encephalopathy. We currently use selective shunts for patients with good liver function. Liver transplantation has been used since the mid 1980s for patients with poor liver function and provides good results for this difficult group of patients. CONCLUSIONS: The selection of patients for these procedures is the key to the successful management of portal hypertension.

Esophageal and Gastric Varices↗
PubMed1995

Prevalence and reversibility of the hepatopulmonary syndrome after liver transplantation. The Cleveland Clinic experience.

To ascertain the prevalence and reversibility of the hepatopulmonary syndrome, we reviewed the cases of 98 patients undergoing liver transplantation at the Cleveland (Ohio) Clinic Foundation from June 1988 through July 1992 and identified 4 patients with clinically recognized hepatopulmonary syndrome (prevalence 4%). All 4 patients ultimately had complete reversal of their disorder. As reviewed herein, the prevalence of the hepatopulmonary syndrome in the current series is lower than in previous reports, possibly reflecting a dependence on its clinical recognition in this series rather than the use of routine screening tests. This report confirms previous experience that the hepatopulmonary syndrome may be reversible after transplantation.

Adult↗
PubMed1994

An NMR study of pyridine associated with DMPC liposomes and magnetically ordered DMPC-surfactant mixed micelles.

With molecular dynamics simulations of phospholipid membranes becoming a reality, there is a growing need for experiments that provide the molecular details necessary to test these computational results. Pyridine is used here to explore the interaction of planar aromatic groups with the water-lipid interface of membranes. It is shown by magic angle spinning 13C nuclear magnetic resonance (NMR) to bind between the glycerol and choline groups of dimyristoylphosphatidylcholine (DMPC) liposomes. The axial pattern for the 31P NMR spectrum of DMPC liposomes is preserved even with more than half of the interfacial sites occupied, indicating that pyridine does not disrupt the lamellar phase of this lipid. 2H NMR experiments of liposomes in deuterium oxide demonstrate that pyridine might promote greater penetration of water into restricted regions in the interface. Magnetically oriented DMPC/surfactant micelles were investigated as a means for improving resolution and sensitivity in NMR studies of species bound to bilayers. The quadrupolar splittings in the 2H NMR spectra of d5-pyridine in DMPC liposomes and magnetically oriented DMPC/Trixon X-100 micelles indicate a common bound state for the two bilayer systems. The well resolved quadrupolar splittings of d5-pyridine in oriented micelles were used to establish the tilt of the pyridine ring relative to the bilayer plane.

Calorimetry, Differential Scanning↗
PubMed1994

Predictors of basic infantry training success.

Because of shrinking resources, the United States military will be forced to carry out its mission in the future with maximum efficiency. Medical problems reduce the efficiency of the training of soldiers. Our project documents the medical problems that occurred in infantry basic trainees and tests easily obtainable information for its ability to predict the impact of medical problems on each trainee. The study involved 649 trainees undergoing a 13-week cycle of basic and advanced infantry training in one of three companies at the United States Army Infantry Training Center, Fort Benning, Georgia. The most common reason for sick call attendance among this group of trainees was upper respiratory infection. While medical illnesses were frequently seen, they did not cause a great deal of lost training time. Training injuries such as foot and lower leg overuse syndromes and patellofemoral knee pain were the primary causes of time lost. The average trainee made 1.58 +/- 1.61 visits to sick call during the cycle, with a total of 4.53 +/- 8.49 days of training time limited by profile. However, many trainees made no sick call visits and the majority of trainees lost no time due to medical problems. The strongest predictors of medical impact on training were a history of cigarette smoking and the initial performance of the trainee on the three events of the Army Physical Fitness Test. Based on the results of this study, we recommend that the military consider cigarette smoking as a negative factor in the selection of recruits and consider that recruits be required to meet some standard of fitness prior to induction.

Adult↗
PubMed1992

The effect of liver denervation on hepatic hemodynamics during hypovolemic shock in swine.

This study tested the hypothesis that the denervated liver is more susceptible to hypovolemic shock than the normal liver. Fourteen swine, seven nondenervated and seven after liver denervation, were studied during hypovolemic shock to 50% of baseline blood pressure. Hepatic artery and portal vein flows were measured using transonic flow probes, and cardiac output and central venous pressure were measured using Swan-Ganz catheters. Hepatic artery flow fell equivalently in the two groups, from 132 +/- 71 to 94 +/- 17 ml/min in the nondenervated group compared with 149 +/- 56 to 91 +/- 55 ml/min in the denervated group. In contrast, portal flow in the denervated group (276 +/- 71 to 119 +/- 53 ml/min) fell significantly (p less than 0.001) more than in the nondenervated group (289 +/- 135 to 194 +/- 70 ml/min). The 58% reduction from baseline in portal flow in the denervated group compared with the 30% reduction in the nondenervated group suggests that the normal compensatory mechanism to maintain portal flow during hypovolemic shock is neurally mediated. It can be hypothesized that sensory afferent fibers might initiate a feedback to splanchnic vasodilatation in response to reduced portal flow. This study supports the hypothesis that the denervated liver is more susceptible to hypovolemic shock.

Animals↗
PubMed1992

High cardiac output of advanced liver disease persists after orthotopic liver transplantation.

This study measured cardiac output before and 1 or 2 yr after orthotopic liver transplantation in 23 patients. Cardiac output was measured by thermodilution before transplantation and by first-pass radionuclide angiocardiography at follow-up. Study patients were selected as those doing well clinically and by standard laboratory tests at 1-yr and 2-yr reevaluations with no evidence of rejection: six had mild recurrent hepatitis shown on biopsy samples. Hepatocyte function was normal at the time of the study as shown by galactose elimination capacity of 442 +/- 90 mg/min. Medications were cyclosporine and prednisone in all patients, azathioprine in 10 patients and a combination of antihypertensive therapy to maintain diastolic blood pressure less than 90 mm Hg in 20 patients. Mean (+/- S.D.) pretransplantation cardiac output was 9.1 +/- 3.1 L/min and remained elevated at 8.3 +/- 2.1 L/min 1 yr, and 9.6 +/- 2.6 L/min (n = 13) 2 yr after transplantation. A significant (p less than 0.001) correlation was found between pretransplant and follow-up cardiac output. End diastolic, end systolic and stroke volumes are all increased in a pattern similar to that seen in end-stage cirrhosis. These data show that the high cardiac output of the hyperdynamic state of advanced liver disease persists after liver transplantation. The mechanisms and consequences of this require further study.

Cardiac Output↗
PubMed1992

Hemodynamics during liver transplantation: the interactions between cardiac output and portal venous and hepatic arterial flows.

Liver blood flow and systemic hemodynamics were measured intraoperatively in 34 patients after liver transplantation. Ultrasound transit-time flow probes measured hepatic arterial and portal venous flow over 10 to 75 min 1 to 3 hr after reperfusion. Cardiac output was measured by thermodilution. Mean cardiac output was 9.5 +/- 2.8 L/min; the mean total liver blood flow of 2,091 +/- 932 ml/min was 23% +/- 11% of cardiac output. Mean portal flow of 1,808 +/- 929 ml/min was disproportionately high at 85% +/- 10% of total liver blood flow. Correlation analysis showed a significant (p less than 0.01; r = 0.42) correlation between cardiac output and portal venous flow and a trend toward negative correlation (p = 0.087) between cardiac output and hepatic arterial flow. These data show that increased flow in the newly transplanted liver is predominantly portal venous flow and is associated with high cardiac output and reduced hepatic arterial flow. In the last 13 patients studied, portal flow was reduced by 50% and the hepatic artery response was measured. We saw a significant (p less than 0.05) increase in hepatic artery flow from 322 +/- 228 to 419 +/- 271 ml/min, indicating an intact hepatic arterial buffer response. The hepatic artery response also showed that it is a reversible rather than a fixed resistance that contributes to the low hepatic artery flow in these patients.

Blood Pressure↗
PubMed1992

Endoscopic variceal sclerosis does not increase the risk of portal venous thrombosis.

In this study the risk of thrombosis in the portal venous system was assessed in patients with chronic variceal bleeding undergoing sclerotherapy. Twenty-two patients with cirrhosis were prospectively studied with angiography before initiation of sclerotherapy and at mean (+/- SD) 26 +/- 17-month (range, 8-63 months) follow-up. Sclerotherapy consisted of flexible endoscopy, intravariceal and paravariceal, using sodium morrhuate (1.5%-2%) and sodium tetradecyl sulfate (0.5%-1.5%), to obliteration. The mean number of sessions was 6.5 +/- 2.2 (range, 3-11), with a mean total amount of sclerosant of 62 +/- 25 mL (range, 25-112 mL). No patient developed splenic or portal vein thrombosis as shown by arteriography. The flow patterns of portal perfusion, vessel size, and coronary vein visualization showed no significant change. Only one patient had spontaneous reversal of portal flow. Splenic vein histology, examined in five patients in whom sclerotherapy failed and who required shunt surgery, was not significantly different from that in eight patients who had no prior sclerotherapy. It is concluded that under the conditions of the current study, chronic sclerotherapy did not increase the risk of thrombosis in the portal venous system and did not significantly alter the histology of the portal hypertensive splenic vein.

Angiography↗
PubMed1992

Distal spleno-renal shunt versus endoscopic sclerotherapy in the prevention of variceal rebleeding. A meta-analysis of 4 randomized clinical trials.

Meta-analysis was used to evaluate 4 clinical trials comparing distal spleno-renal shunt (DSRS) with endoscopic sclerotherapy (EVS) in the prevention of variceal rebleeding: the interval between bleeding and therapy ranges from < 14 days to > 100 days. A questionnaire was sent to each author of the published trials concerning methods, definitions and results of the trials in order to obtain more detailed and up-to-date information. The selected end-points for the meta-analysis were: rebleeding, mortality and chronic encephalopathy. Analysis of the results in the questionnaires was made using the method proposed by Collins. The pooled relative risk (i.e. the combined Odds ratio of each trial as an estimate of overall efficacy) of rebleeding was statistically reduced by DSRS (0.16; 95% confidence interval 0.10-0.27). Despite this, the overall risk of death following DSRS was only marginally decreased (0.78; 95% confidence interval 0.47-1.29); the lack of homogeneity in the results does not permit any significant conclusions on this end-point. However, in non-alcoholic patients, the decrease in risk of death was greater, and this without heterogeneity, following DSRS than EVS (0.59; 95% confidence interval 0.23-1.50). The overall risk of chronic encephalopathy was slightly increased after DSRS (1.86; 95% confidence interval 0.90-3.86). In conclusion, DSRS significantly reduced the risk of rebleeding compared to EVS without increasing the risk of chronic hepatic encephalopathy. However, DSRS did not significantly affect the overall death risk. Only in non-alcoholic disease did it seem to show an advantage over EVS.

Brain Diseases↗
PubMed1992

Identifying objects across saccades: effects of extrafoveal preview and flanker object context.

Two object-naming experiments explored the influence of extrafoveal preview information and flanker object context on transsaccadic object identification. Both the presence of an extrafoveal preview of the target object and the contextual constraint provided by extrafoveal flanker objects were found to influence the speed of object identification, but the latter effect occurred only when an extrafoveal preview of the target object was not presented prior to fixation. The context effect was found to be due to facilitation from related flankers rather than inhibition from unrelated flankers. No evidence was obtained for the hypothesis that constraining context can increase the usefulness of an extrafoveal preview of a to-be-fixated object.

Adult↗
PubMed1992

Object identification in context: the visual processing of natural scenes.

When we view a natural visual scene, we seem able to determine effortlessly the scene's semantic category, constituent objects, and spatial relations. How do we accomplish this visual-cognitive feat? The commonly held explanation is known as the schema hypothesis, according to which a visual scene is rapidly identified as a member of a semantic category, and predictions generated from the scene category are then used to aid subsequent object identification. In this paper I will first outline and offer a critique of the evidence that has been taken to support the schema hypothesis. I will then offer an alternative framework for understanding scene processing, which I will call the local-processing hypothesis. This hypothesis assumes a modular, informationally-encapsulated architecture, and explicitly includes the role of covert visual attention in scene processing.

Attention↗
PubMed1992

Selective shunt in the management of variceal bleeding in the era of liver transplantation.

This study reports the Emory experience with 147 distal splenorenal shunts (DSRS) and 110 orthotopic liver transplants (OLT) between January 1987 and December 1991. The purpose was to clarify which patients with variceal bleeding should be treated by DSRS versus OLT. Distal splenorenal shunts were selected for patients with adequate or good liver function. Orthotopic liver transplant was offered to patients with end-stage liver disease who fulfilled other selection criteria. The DSRS group comprised 71 Child's A, 70 Child's B, and 6 Child's C patients. The mean galactose elimination capacity for all DSRS patients was 330 +/- 98 mg/minute, which was significantly (p less than 0.01) above the galactose elimination capacity of 237 +/- 82 mg/minute in the OLT group. Survival analysis for the DSRS group showed 91% 1-year and 77% 3-year survival, which was better than the 74% 1-year and 60% 3-year survivals in the OLT group. Variceal bleeding as a major component of end-stage disease leading to OLT had significantly (p less than 0.05) poorer survival (50%) at 1 year compared with patients without variceal bleeding (80%). Hepatic function was maintained after DSRS, as measured by serum albumin and prothrombin time, but galactose elimination capacity decreased significantly (p less than 0.05) to 298 +/- 97 mg/minute. Quality of life, measured by a self-assessment questionnaire, was not significantly different in the DSRS and OLT groups. Hospital charges were significantly higher for OLT (median, $113,733) compared with DSRS ($32,674). These data support a role for selective shunt in the management of patients with variceal bleeding who require surgery and have good hepatic function. Transplantation should be reserved for patients with end-stage liver disease. A thorough evaluation, including tests of liver function, help in selection of the most appropriate therapeutic approach.

Adult↗