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Biomedical subjects

T E Read

Publications and source records attributed to T E Read.

30 records · Page 2Linked to original sources
PubMed1997

Afferent limb obstruction complicating ileal pouch-anal anastomosis.

PURPOSE: Small-bowel obstruction is a common complication after ileal pouch-anal anastomosis (IPAA). Acute angulation of the afferent limb at the pouch inlet is the cause of obstruction in a subset of patients requiring laparotomy. METHODS: Patients were identified from the Lahey Clinic ileoanal pouch registry, a prospective computerized database of all patients who have undergone IPAA since 1980. Records of patients who were identified as having afferent limb obstruction as a cause of bowel obstruction after IPAA were reviewed. RESULTS: A total of 567 patients had undergone total proctocolectomy and ileoanal J-pouch at time of the study. Of 122 patients with one or more episodes of obstruction after IPAA, 48 required operative intervention. Afferent limb obstruction was identified as the cause of obstruction in six patients (12 percent). The most common presentation was recurrent partial obstruction (4 of 6 patients). Contrast small-bowel series and enemas were suggestive of obstruction in four of six patients, the most consistent radiographic finding being small-bowel dilation to the level of the pouch inlet. All patients underwent laparotomy for unresolved obstruction. Intraoperatively, the afferent limb was found to be adherent posterior to the pouch, causing acute angulation at the pouch inlet. Rather than risk injury to the pouch or its mesentery, the obstruction was bypassed by side-to-side anastomosis of the afferent limb to the pouch (enteroenterostomy) in five of six patients. One patient underwent ileostomy only because of technical considerations. Two patients required re-exploration and pexy of the afferent limb to the pelvic sidewall (pouchopexy) to relieve recurrent afferent limb obstruction. CONCLUSION: Afferent limb obstruction should be suspected in patients with recurrent obstruction after IPAA. Bypass of the obstructed segment from distal ileum to the pouch is safe and effective treatment. Because of the risk of recurrent afferent limb angulation, concurrent pouchopexy should be considered.

Adult↗
PubMed1997

Detection of recurrent and metastatic colorectal cancer: comparison of positron emission tomography and computed tomography.

BACKGROUND: This study evaluates the clinical value of positron emission tomography (PET) with 2-[F-18] fluoro-2-deoxy-D-glucose (FDG) as compared to computed tomography (CT) in patients with suspected recurrent or metastatic colorectal cancer (CRC). METHODS: A retrospective review of the records of 58 patients who had FDG-PET for evaluation of recurrent or advanced primary CRC was performed. FDG-PET results were compared with those of CT and correlated with operative and histopathologic findings, or with clinical course and autopsy reports. RESULTS: Recurrent or advanced primary CRC was diagnosed in 40 and 11 patients, respectively. The sensitivity and specificity of FDG-PET were 91% and 100% for detecting local pelvic recurrence, and 95% and 100% for hepatic metastases. These values were superior to CT, which had sensitivity and specificity of 52% and 80% for detecting pelvic recurrence, and 74% and 85% for hepatic metastases. FDG-PET correctly identified pelvic recurrence in 19 of 21 patients; CT was negative in 6 of these patients and equivocal in 4. FDG-PET was superior to CT in detecting multiple hepatic lesions and influenced clinical management in 10 of 23 (43%) patients. CONCLUSION: FDG-PET is more sensitive than CT in the clinical assessment of patients with recurrent or metastatic CRC, and provides an accurate means of selecting appropriate treatment for these patients.

Adult↗
PubMed1997

Laparoscopic-assisted ileocolic resections in patients with Crohn's disease: are abscesses, phlegmons, or recurrent disease contraindications?

BACKGROUND: Because of the inflammatory nature of Crohn's disease, ileocolic resections are often difficult to perform, especially if an abscess, phlegmon, or recurrent disease at a previous ileocolic anastomosis is present. Our goal was to determine whether the above factors are contraindications to a successful laparoscopic-assisted ileocolic resection. METHODS: Between 1992 and 1996, 46 laparoscopic-assisted ileocolic resections were attempted. Fourteen patients had an abscess or phlegmon treated with bowel rest before operation (group I), 10 patients had recurrent Crohn's disease at the previous ileocolic anastomosis (group II), and 22 patients had no previous operation and no phlegmon or abscess associated with their disease (group III). These groups were compared with each other and with 70 consecutive open ileocolic resections for Crohn's disease during the same time period (group IV). RESULTS: Operative blood loss and time were greater in group IV than in groups I, II, and III (245 versus 151, 131, and 195 ml, respectively, and 202 versus 152, 144, and 139 minutes, respectively). Conversion to open procedure occurred in 5 patients (group I, 1 [7%]; group II, 2 [20%]; group III, 2 [9%]). Morbidity was highest in group IV (21% versus 0%, 10%, and 10%, respectively). Only one patient died (group IV, 1%). Length of hospital stay was longest in group IV (7.9 versus 4.8, 3.9, and 4.5 days, respectively). CONCLUSIONS: The laparoscopic-assisted approach to Crohn's disease is feasible and safe with good outcomes. Co-morbid preoperative findings such as abscess, phlegmon, or recurrent disease at the previous ileocolic anastomosis are not contraindications to a successful laparoscopic-assisted ileocolic resection in select patients.

Abdominal Abscess↗
PubMed1995

Triglyceride-rich lipoproteins prevent septic death in rats.

Triglyceride-rich lipoproteins bind and inactive bacterial endotoxin in vitro and prevent death when given before a lethal dose of endotoxin in animals. However, lipoproteins have not yet been demonstrated to improve survival in polymicrobial gram-negative sepsis. We therefore tested the ability of triglyceride-rich lipoproteins to prevent death after cecal ligation and puncture (CLP) in rats. Animals were given bolus infusions of either chylomicrons (1 g triglyceride/kg per 4 h) or an equal volume of saline for 28 h after CLP. Chylomicron infusions significantly improved survival (measured at 96 h) compared with saline controls (80 vs 27%, P < or = 0.03). Chylomicron infusions also reduced serum levels of endotoxin, measured 90 min (26 +/- 3 vs 136 +/- 51 pg/ml, mean +/- SEM, P < or = 0.03) and 6 h (121 +/- 54 vs 1,026 +/- 459 pg/ml, P < or = 0.05) after CLP. The reduction in serum endotoxin correlated with a reduction in serum tumor necrosis factor, measured 6 h after CLP (0 +/- 0 vs 58 +/- 24 pg/ml, P < or = 0.03), suggesting that chylomicrons improve survival in this model by limiting macrophage exposure to endotoxin and thereby reducing secretion of inflammatory cytokines. Infusions of a synthetic triglyceride-rich lipid emulsion (Intralipid; KabiVitrum, Inc., Alameda, CA) (1 g triglyceride/kg) also significantly improved survival compared with saline controls (71 vs 27%, P < or = 0.03). These data demonstrate that triglyceride-rich lipoproteins can protect animals from lethal polymicrobial gram-negative sepsis.

Animals↗
PubMed1995

Triglyceride-rich lipoproteins improve survival when given after endotoxin in rats.

BACKGROUND: Triglyceride-rich lipoproteins have been shown to bind bacterial endotoxin and inhibit its activity in vitro and to protect animals from death when administered before a lethal injection of endotoxin. We now demonstrate that triglyceride-rich lipoproteins can neutralize the toxic effects of endotoxin already in circulation. METHODS: Rats were infused with a lethal dose of endotoxin, followed at various time intervals by an infusion of either mesenteric lymph containing nascent chylomicrons (1 gm chylomicron triglyceride/kg) or an equal volume of normal saline solution. Survival was measured at 48 hours. The experiment was then repeated, substituting the synthetic triglyceride-rich lipid emulsion (1 gm/kg) for chylomicrons. We also measured the clearance and tissue distribution of radioiodinated endotoxin in rats treated subsequently with chylomicrons or saline solution. RESULTS: Chylomicron infusions significantly improved survival when given up to 30 minutes after a lethal dose of endotoxin (p < 0.05). Chylomicrons accelerated endotoxin clearance from the blood and increased endotoxin uptake by the liver. The synthetic triglyceride-rich lipid emulsion significantly improved survival when given up to 15 minutes after a lethal dose of endotoxin (p < 0.05). CONCLUSIONS: Triglyceride-rich lipoproteins and synthetic triglyceride-rich lipid emulsions significantly improve survival of rats when given after a lethal dose of endotoxin. Lipoprotein treatment accelerates endotoxin clearance to the liver, which may account for the observed protection. These data suggest a possible therapeutic role for triglyceride-rich lipoproteins or synthetic lipid emulsions in the treatment of the endotoxemia of gram-negative sepsis.

Animals↗
PubMed1993

Chylomicrons enhance endotoxin excretion in bile.

Chylomicrons prevent endotoxin toxicity and increase endotoxin uptake by hepatocytes. As a consequence, less endotoxin is available to activate macrophages, thereby reducing tumor necrosis factor secretion. To determine whether the chylomicron-mediated increase in hepatocellular uptake of endotoxin results in increased endotoxin excretion into bile, we examined bile after endotoxin administration. A sublethal dose (7 micrograms/kg) of 125I-endotoxin was incubated with either rat mesenteric lymph containing nascent chylomicrons (500 mg of chylomicron triglyceride per kg of body weight) or an equal volume of normal saline (controls) for 3 h and then infused into male Sprague-Dawley rats. Bile samples were collected via a common bile duct catheter for 24 h. Infusion of endotoxin incubated with chylomicrons increased biliary excretion of endotoxin by 67% at 3 h (P < or = 0.006) and by 20% at 24 h (P < or = 0.01) compared with infusion of endotoxin incubated in saline. Endotoxin activity, as measured by the Limulus assay, was not detected in the bile of test animals. However, endotoxin activity was detected after hot phenol-water extraction of bile, demonstrating that endotoxin is inactive in the presence of bile but retains bioactivity after hepatic processing. Since the majority of an intravenous endotoxin load has been shown to be cleared by the liver, acceleration of hepatocyte clearance and biliary excretion of endotoxin may represent a component of the mechanism by which chylomicrons protect against endotoxin-induced lethality.

Animals↗
PubMed1993

Chylomicrons alter the fate of endotoxin, decreasing tumor necrosis factor release and preventing death.

The hypertriglyceridemia of infection was traditionally thought to represent the mobilization of substrate to fuel the body's response to the infectious challenge. However, we have previously shown that triglyceride-rich lipoproteins can protect against endotoxin-induced lethality. The current studies examine the mechanism by which this protection occurs. Rats infused with a lethal dose of endotoxin preincubated with chylomicrons had a reduced mortality compared with rats infused with endotoxin alone (15 vs. 76%, P < 0.001). Preincubation with chylomicrons increased the rate of clearance of endotoxin from plasma and doubled the amount of endotoxin cleared by the liver (30 +/- 1 vs. 14 +/- 2% of the total infused radiolabel, P < 0.001). In addition, autoradiographic studies showed that chylomicrons directed more of the endotoxin to hepatocytes and away from hepatic macrophages. Rats infused with endotoxin plus chylomicrons also showed reduced peak serum levels of tumor necrosis factor as compared with controls (14.2 +/- 3.3 vs. 44.9 +/- 9.5 ng/ml, mean +/- SEM, P = 0.014). In separate experiments, chylomicrons (1,000 mg triglyceride/kg) or saline were infused 10 min before the infusion of endotoxin. Chylomicron pretreatment resulted in a reduced mortality compared with rats infused with endotoxin alone (22 vs. 78%, P < 0.005). Therefore, chylomicrons can protect against endotoxin-induced lethality with and without preincubation with endotoxin. The mechanism by which chylomicrons protect against endotoxin appears to involve the shunting of endotoxin to hepatocytes and away from macrophages, thereby decreasing macrophage activation and the secretion of cytokines.

Animals↗
PubMed1993

The protective effect of serum lipoproteins against bacterial lipopolysaccharide.

Lipoproteins bind and inactivate bacterial endotoxin, both in vitro and in vivo. Both cholesterol ester-rich and TG-rich lipoproteins, and TG-rich lipid emulsions can prevent death in mice when pre-incubated with a lethal dose of endotoxin before intraperitoneal administration. Chylomicrons can also prevent death when given intravenously after endotoxin in rats. The metabolic fate of lipoprotein-bound endotoxin appears to be directed by the lipoprotein particle. When administered with chylomicrons, the plasma clearance and hepatic uptake of endotoxin are enhanced. Endotoxin is shunted preferentially to hepatocytes and away from hepatic macrophages, thereby increasing endotoxin excretion [corrected] in bile. The survival benefit and alterations in metabolism afforded by chylomicrons correlate with a reduction in peak serum levels of tumour necrosis factor (TNF), providing a possible mechanism by which lipoproteins protect against endotoxin-induced death. These findings suggest a possible role for lipoproteins or lipid emulsions in the body's defence against endotoxaemia.

Animals↗
PubMed1993

Cigarette smoke alters chylomicron metabolism in rats.

PURPOSE: Cigarette smoking may exert its atherogenic effect by delaying the plasma clearance of dietary fat and cholesterol, allowing more time for their interaction with the artery wall. To study the effects of smoke on chylomicron metabolism in rats, we examined the metabolic effects of smoke on both whole animals and chylomicron particles in vitro. METHODS: Carbon 14- and hydrogen 3-labeled chylomicrons were injected intravenously into smoke-treated rats and control rats that were not exposed to smoke (sham smoked). Plasma clearance, hepatic uptake, and heart binding were measured. In a second set of experiments, chylomicron particles were exposed to cigarette smoke in vitro by either: (1) passing smoke through chylomicrons suspended in saline solution (SCM) or (2) passing smoke through saline solution alone, then mixing the saline solution with chylomicrons (CM + SS). Normal (non-smoke exposed) rats were infused with either SCM, CM + SS, or control chylomicrons (CCM). Plasma clearance, hepatic uptake, and heart binding were again measured. RESULTS: The initial plasma clearance time of labeled chylomicrons did not differ between smoke-treated and control animals. However, hepatic uptake of chylomicron cholesterol was slower in smoke-treated animals (46.1% +/- 0.9% of injected dose) than in controls (61.5% +/- 2.1%, p < 0.001). In contrast, more labeled chylomicrons remained in the heart of smoke-treated rats than controls (0.89% +/- 0.18% vs 0.45% +/- 0.05%, p < 0.05). Disappearance of 14C-labeled cholesterol from blood was delayed in rats injected with SCM (half-life = 9.0 +/- 0.4 minutes) and CM + SS (half-life = 8.0 +/- 0.4 minutes), compared with the time in rats injected with CCM (6.6 +/- 0.3 minutes, p < 0.05). Hepatic uptake of SCM (40.6% +/- 1.9% of injected dose) and CM + SS (45.0% +/- 1.9%) was less than that of CCM (60.7% +/- 4.4%, p < 0.05). In addition, the binding to the heart increased from 0.97% +/- 0.29% (CCM) to 2.45% +/- 0.30% with the infusion of SCM (p < 0.05). The binding in the heart of CM + SS (0.95% +/- 0.04%) was not different from that of CCM. CONCLUSIONS: These data demonstrate for the first time that cigarette smoke exposure prolongs chylomicron residence time in tissues (heart) and delays hepatic uptake of chylomicron cholesterol in rats. The effect is present when either the animal or the chylomicron particle is exposed to smoke. We hypothesize that prolonged binding of relatively cholesterol-rich chylomicron remnants to endothelial surfaces could create a more atherogenic postprandial milieu.

Animals↗
PubMed1989

UCH/RNID single channel extracochlear implant: results in thirty profoundly deafened adults.

The University College Hospital/Royal National Institute for the Deaf (UCH/RNID) Cochlear Implant Programme has now given single channel extracochlear implants to forty profoundly deafened adults. Audiological, psychophysical, speech perceptual and subjective results for the first thirty cases are described. The main findings can be summarised as follows: 1. Users of the single channel extracochlear implant gained considerable improvements in their lipreading and communication ability, as assessed by both objective testing and by the patients' own reports. All acquired useful awareness of environmental sounds and an improvement in their quality of life; some also showed improvements in their own speech. A small number were capable of some open-set speech discrimination without lipreading. 2. Extracochlear implantation was not found to destroy residual hearing, although it did cause slight deterioration in hearing thresholds in some cases. 3. Our results so far suggest that patients deafened by meningitis are likely to obtain less benefit from a single channel cochlear implant than those deafened by other causes. Better results were also achieved by younger, more recently deafened patients and those who were good lipreaders. Despite the emergence of these trends we have not yet found a reliable way to predict benefit from an implant on the basis of preoperative variables. 4. Self-reported measures of the benefits of the implant correlated well with the objective test results, but also revealed important information that was not available from the objective tests. In particular, they showed that the improvement in lipreading provided by the implant was reduced in noisy conditions.

Acoustic Stimulation↗
PubMed1989

Improvement in speech production following use of the UCH/RNID cochlear implant.

It has been noted that the speech of adults who become deaf can deteriorate, particularly in terms of suprasegmental features. The speech production skills of 30 post-lingually deafened adults who had derived no benefit from hearing aids was assessed before and after cochlear implantation using subjective and objective measures. Significant improvement in speech production was heard in 57 per cent of subjects; 29 subjects were judged to have improved speech production after using their cochlear implant for one year.

Cochlear Implants↗