The Fallacy of Misplaced Presumption

One takes one's word that p when a source vouches for p and one accepts the word of that source. If the source is reliable in this case, p is acceptable. The reliability of the source is a measure of its plausibility. If a source has the relevant competence, credibility, authority, that word is acceptable. Likewise, the word may be acceptable if accompanied by a cogent argument, but presumption may be misplaced. One may recognize a presumption for a statement when such recognition is not justified, the positive version of the fallacy. One may refuse to recognize a presumption for a statement when there really is a presumption for the statement, the negative version of the fallacy. The essay proceeds to explore various dimensions of when it is justified to take a source's word for a claim, and when it is justified to reject a claim from a source. The discussion ranges over considerations of sexism and race, cultural differences, and the relationship of presumptions to fallacies. Also considered is the role of trust in taking someone's word and the factors involved in trusting someone.

Immunomagnetic-Enriched Subpopulations of Melanoma Circulating Tumour Cells (CTCs) Exhibit Distinct Transcriptome Profiles

Cutaneous melanoma circulating tumour cells (CTCs) are phenotypically and molecularly heterogeneous. We profiled the gene expression of CTC subpopulations immunomagnetic-captured by targeting either the melanoma-associated marker, MCSP, or the melanoma-initiating marker, ABCB5. Firstly, the expression of a subset of melanoma genes was investigated by RT-PCR in MCSP-enriched and ABCB5-enriched CTCs isolated from a total of 59 blood draws from 39 melanoma cases. Of these, 6 MCSP- and 6 ABCB5-enriched CTC fractions were further analysed using a genome-wide gene expression microarray. The transcriptional programs of both CTC subtypes included cell survival maintenance, cell proliferation, and migration pathways. ABCB5-enriched CTCs were specifically characterised by up-regulation of genes involved in epithelial to mesenchymal transition (EMT), suggesting an invasive phenotype. These findings underscore the presence of at least two distinct melanoma CTC subpopulations with distinct transcriptional programs, which may have distinct roles in disease progression and response to therapy.

Clinical Application of Circulating Tumor Cells and Circulating Tumor DNA in Uveal Melanoma

Purpose

To evaluate the feasibility of using circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) for the management of uveal melanoma (UM).

Patients and Methods

Low-coverage whole-genome sequencing was used to determine somatic chromosomal copy number alterations (SCNAs) in primary UM tumors, ctDNA, and whole-genome amplified CTCs. CTCs were immunocaptured using an antimelanoma-associated chondroitin sulfate antibody conjugated to magnetic beads and immunostained for melanoma antigen recognised by T cells 1 (MART1)/glycoprotein 100 (gp100)/S100 calcium-binding protein β (S100β). ctDNA was quantified using droplet digital polymerase chain reaction assay for mutations in the GNAQ, GNA11, PLCβ4, and CYSLTR2 genes.

Results

SCNA analysis of CTCs and ctDNA isolated from a patient with metastatic UM showed good concordance with the enucleated primary tumor. In a cohort of 30 patients with primary UM, CTCs were detected in 58% of patients (one to 37 CTCs per 8 mL of blood), whereas only 26% of patients had detectable ctDNA (1.6 to 29 copies/mL). The presence of CTCs or ctDNA was not associated with tumor size or other prognostic markers. However, the frequent detection of CTCs in patients with early-stage UM supports a model in which CTCs can be used to derive tumor-specific SCNA relevant for prognosis. Monitoring of ctDNA after treatment of the primary tumor allowed detection of metastatic disease earlier than ¹⁸F-labeled fluorodeoxyglucose positron emission tomography in two patients.

Conclusion

The presence of CTCs in localized UM can be used to ascertain prognostic SCNA, whereas ctDNA can be used to monitor patients for early signs of metastatic disease. This study paves the way for the analysis of CTCs and ctDNA as a liquid biopsy that will assist with treatment decisions in patients with UM.

Isolation and detection of circulating tumour cells from metastatic melanoma patients using a slanted spiral microfluidic device

Circulating Tumour Cells (CTCs) are promising cancer biomarkers. Several methods have been developed to isolate CTCs from blood samples. However, the isolation of melanoma CTCs is very challenging as a result of their extraordinary heterogeneity, which has hindered their biological and clinical study. Thus, methods that isolate CTCs based on their physical properties, rather than surface marker expression, such as microfluidic devices, are greatly needed in melanoma. Here, we assessed the ability of the slanted spiral microfluidic device to isolate melanoma CTCs via label-free enrichment. We demonstrated that this device yields recovery rates of spiked melanoma cells of over 80% and 55%, after one or two rounds of enrichment, respectively. Concurrently, a two to three log reduction of white blood cells was achieved with one or two rounds of enrichment, respectively. We characterised the isolated CTCs using multimarker flow cytometry, immunocytochemistry and gene expression. The results demonstrated that CTCs from metastatic melanoma patients were highly heterogeneous and commonly expressed stem-like markers such as PAX3 and ABCB5. The implementation of the slanted microfluidic device for melanoma CTC isolation enables further understanding of the biology of melanoma metastasis for biomarker development and to inform future treatment approaches.

Detection of BRAF-V600E and V600K in melanoma circulating tumour cells by droplet digital PCR

OBJECTIVES

Defining the BRAF mutation status in metastatic melanoma patients is critical to selecting patients for therapeutic treatment with targeted therapies. Circulating tumour cells (CTCs) can provide an alternative source of contemporaneous tumour genetic material. However methodologies to analyse the presence of rare mutations in a background of wild-type DNA requires a detailed assessment. Here we evaluate the sensitivity of two technologies for cancer mutation detection and the suitability of whole genome amplified DNA as a template for the detection of BRAF-V600 mutations.

DESIGN AND METHODS

Serial dilutions of mutant BRAF-V600E DNA in wild-type DNA were tested using both competitive allele-specific PCR (castPCR) and droplet digital PCR (ddPCR), with and without previous whole genome amplification (WGA). Using immunomagnetic beads, we partially enriched CTCs from blood obtained from metastatic melanoma patients with confirmed BRAF mutation positive tumours and extracted RNA and DNA from the CTCs. We used RT-PCR of RNA to confirm the presence of melanoma cells in the CTC fraction then the DNAs of CTC positive fractions were WGA and tested for BRAF V600E or V600K mutations by ddPCRs.

RESULTS

WGA DNA produced lower than expected fractional abundances by castPCR analysis but not by ddPCR. Moreover, ddPCR was found to be 200 times more sensitive than castPCR and in combination with WGA produced the most concordant results, with a limit of detection of 0.0005%. BRAF-V600E or V600K mutated DNA was detected in 77% and 44%, respectively, of enriched CTC fractions from metastatic melanoma patients carrying the corresponding mutations.

CONCLUSIONS

Our results demonstrate that using ddPCR in combination with WGA DNA allows the detection with high sensitivity of cancer mutations in partially enriched CTC fractions.

Monitoring changes in circulating tumour cells as a prognostic indicator of overall survival and treatment response in patients with metastatic melanoma

Background

New effective treatments for metastatic melanoma greatly improve survival in a proportion of patients. However biomarkers to identify patients that are more likely to benefit from a particular treatment are needed. We previously reported on a multimarker approach for the detection of heterogenous melanoma circulating tumour cells (CTCs). Here we evaluated the prognostic value of this multimarker quantification of CTCs and investigated whether changes in CTC levels during therapy can be used as a biomarker of treatment response and survival outcomes.

Methods

CTCs were captured by targeting the melanoma associated markers MCSP and MCAM as well as the melanoma stem cell markers ABCB5 and CD271. CTCs were quantified in 27 metastatic melanoma patients treated by surgery or with vemurafenib, ipilimumab or dacarbazine. Patients were enrolled prospectively and CTC counts performed at baseline (prior to treatment), during and after treatment.

Results

Baseline CTC numbers were not found to be prognostic of overall survival nor of progression free survival. However, a low baseline CTC number was associated with a rapid response to vemurafenib therapy. A decrease in CTCs after treatment initiation was associated with response to treatment and prolonged overall survival in vemurafenib treated patients.

Conclusions

Measuring changes in CTC numbers during treatment is useful for monitoring therapy response in melanoma patients and for providing prognostic information relating to overall survival. Further studies with larger sample sizes are required to confirm the utility of CTC quantification as a companion diagnostic for metastatic melanoma treatment.

Evaluation of a multi-marker immunomagnetic enrichment assay for the quantification of circulating melanoma cells

Background

Circulating melanoma cells (CMCs) are thought to be valuable in improving measures of prognosis in melanoma patients and may be a useful marker of residual disease to identify non-metastatic patients requiring adjuvant therapy. We investigated whether immunomagnetic enrichment targeting multiple markers allows more efficient enrichment of CMCs from patient peripheral blood than targeting a single marker. Furthermore, we aimed to determine whether the number of CMCs in patient blood was associated with disease stage.

Methods

We captured CMCs by targeting the melanoma associated markers MCSP and MCAM as well as the melanoma stem cell markers ABCB5 and CD271, both individually and in combination, by immunomagnetic enrichment. CMCs were enriched and quantified from the peripheral blood of 10 non-metastatic and 13 metastatic melanoma patients.

Results

Targeting all markers in combination resulted in the enrichment of more CMCs than when any individual marker was targeted (p < 0.001-0.028). Furthermore, when a combination of markers was targeted, a greater number of CMCs were enriched in metastatic patients compared with non-metastatic patients (p = 0.007).

Conclusions

Our results demonstrated that a combination of markers should be targeted for optimal isolation of CMCs. In addition, there are significantly more CMCs in metastatic patients compared with non-metastatic patients and therefore quantification of CMCs may prove to be a useful marker of disease progression.

Specificity of Stroop interference in patients with pain and PTSD

The authors investigated processing of threat words in motor vehicle accident survivors using a modified Stroop procedure. Three samples were included: 28 participants with comorbid posttraumatic stress disorder (PTSD) and pain, 26 participants with pain without PTSD, and 21 participants without pain or any psychiatric conditions. Four word categories were used: (a) accident words, (b) pain words, (c) positive words, and (d) neutral words. This study examined whether processing biases would occur to accident words only in participants with PTSD or if these biases would also be noted in the No PTSD/Pain sample. Additionally, this study examined whether processing biases would be noted to pain words in the 2 pain samples, irrespective of PTSD. Overall, color naming was significantly slower in the PTSD/Pain group in comparison with the other groups. As well, the PTSD/Pain sample showed significant response delays to both accident and pain-related words, whereas patients with No PTSD/Pain showed delays to pain stimuli only.

Specificity of Stroop interference in patients with pain and PTSD

The authors investigated processing of threat words in motor vehicle accident survivors using a modified Stroop procedure. Three samples were included: 28 participants with comorbid posttraumatic stress disorder (PTSD) and pain, 26 participants with pain without PTSD, and 21 participants without pain or any psychiatric conditions. Four word categories were used: (a) accident words, (b) pain words, (c) positive words, and (d) neutral words. This study examined whether processing biases would occur to accident words only in participants with PTSD or if these biases would also be noted in the No PTSD/Pain sample. Additionally, this study examined whether processing biases would be noted to pain words in the 2 pain samples, irrespective of PTSD. Overall, color naming was significantly slower in the PTSD/Pain group in comparison with the other groups. As well, the PTSD/Pain sample showed significant response delays to both accident and pain-related words, whereas patients with No PTSD/Pain showed delays to pain stimuli only.

Cognitive interference for trauma cues in sexually abused adolescent girls with posttraumatic stress disorder

Investigated cognitive processing of fear-relevant information in sexually abused adolescent girls with posttraumatic stress disorder (PTSD) using a modified Stroop procedure (MSP). Participants were 20 sexually abused girls with PTSD, 13 sexually abused girls without PTSD, and 20 nonvictimized girls who served as controls, 11 to 17 years old. Word conditions included abuse-related threat, developmentally relevant (related to the experience of sexual abuse, e.g., trust, secrecy, and intimacy), general threat, positive, and neutral. Girls with PTSD were expected to show cognitive interference for trauma-related words as well as for developmentally relevant words, relative to adolescents without PTSD. Overall color naming was significantly slower in the PTSD group than in the nonabused controls. Contrary to expectation, all participants demonstrated cognitive interference for trauma-related words. Relevant theoretical and methodological issues are highlighted.

Rush to judgment? Child protective services and allegations of sexual abuse

Two hundred and ninety-three randomly selected cases from a child protection service agency in a large western New York county were examined to test the hypothesis that sexual abuse allegations are investigated and processed more intensively than cases alleging other types of maltreatment. Contrary to the hypothesis, allegations of sexual abuse were substantiated at a lower rate, not investigated more intensively, and not offered more services than were other cases.

Weight loss after extended gastric bypass

BACKGROUND

Gastric bypass (GBP) is the most effective method for controlling morbid obesity. Previously we showed that extending the length of the Roux limb increased weight loss. We have done over 400 obesity operations during the past 20 years. The current study consists of patients from the last 10 years of our experience and compares short to extended Roux-en-Y GBP.

METHODS

Data from all patients operated at the Ottawa General Obesity Clinic were entered into a database on an ongoing basis, and those from the past 10 years were analyzed. All patients had standardized preoperative investigations and postoperative follow-up. Details of these and of the operative technique are provided in the manuscript.

RESULTS

The preoperative weight and BMI were 129 +/- 2 kg, and 46 +/- 2 kg/m2, respectively. The mean weight loss prior to surgery was -2 +/- 21 kg. The results were classified, by percentage weight loss as: 'excellent' = > 35%; 'good' = 25-34%; 'poor' = 15-24%; and 'failure' = < 15%. Sixty-five patients (69%) were available for 2-year follow-up. At this time, mean percentage weight loss was 34 +/- 2 versus 40 +/- 1 for the short Roux (45-135 cm) and long Roux (180-225 cm) groups, respectively (P < 0.01). There were no deaths, leaks, splenectomies or intra-abdominal infections. The incidence of hernia and/or reoperation for bowel obstruction was 35/121 or 29%. The overall incidence of diarrhea was 16/121 (13%) and 6/121 (5%) at 12 and 24 months. Quality of life is significantly impaired in at least three of these patients, all with extended limbs. Major vitamin deficiencies, alterations in liver functions, or other metabolic complications did not occur.

CONCLUSIONS

Gastric bypass is the procedure of choice for morbid obesity. Weight loss is marginally improved in proportion to the length of the Roux limb but at a risk of diarrhea, which occasionally may not manifest itself for 8 to 12 months. It is important that methods be devised to correct follow-up, incisional hernias and diarrhea.

Child age and caseworker attention in child protective services investigations

Infants and toddlers are at increased risk for severe/fatal abuse, often at the hands of male perpetrators. This paper examined whether child maltreatment cases involving younger children receive more casework services, overall caseworker activity (e.g., home visits, phone contacts), and are more likely to be substantiated, particularly if a male perpetrator is involved. The randomly selected sample consisted of 293 child abuse and neglect reports in a large county in Western New York in 1993. Hierarchical regression analyses showed that younger children generally receive more overall services and caseworker activity, and that while age makes a significant contribution after the decision has been made to substantiate a case, it does not have the same effect on the initial decision of whether or not to substantiate. Gender of the perpetrator did not reliably predict caseworker attention.

Lengthening the Roux-Y Limb Increases Weight Loss after Gastric Bypass: a preliminary report

We compared two variants of gastric bypass which have been used at our hospital since 1984. Initially all patients had a standard 45 cm Roux-Y anastomosed to a 30 cc gastric pouch. Subsequently we increased the length of the Roux-Y from 45 to 90 cm. In all patients the jejunum was divided 15-20 cm from the ligament of Treitz. There were six males, and 49 females with a mean age of 35 years. All were at least twice their ideal weights (range 91.5 to 179, X = 127.6). Percentage follow-up ranged from 100% at three months to 13% at 66 months for both the standard and lengthened Roux-Y groups. There were no major technical or metabolic complications. Doubling the length of the standard Roux-Y limb increased the percentage excess weight lost by approximately 6% without diarrhea or other apparent metabolic, sequelae.

Feeding jejunostomy: a safe adjunct to laparotomy

It is well established that a feeding jejunostomy is an invaluable adjuvant for use in critically ill and malnourished patients. What is not well known are the complications of inserting these tubes. Some surgeons are reluctant to insert feeding tubes unless the indications are very clear. From their experience with the insertion of 133 feeding jejunostomy tubes during a 3-year period, the authors conclude that the complications associated with the insertion of such tubes are few and that the procedure is justified even if the tube is never used.

Comparison of Marlex and Gore-tex to repair abdominal wall defects in the rat

Marlex and Gore-tex, two prosthetic materials used to close abdominal wounds, were compared with respect to strength and adhesion formation. A 2.5 X 3.5-cm full-thickness area of abdominal wall was excised in 32 CD rats. The defect was repaired using identically sized patches of Marlex or 1-mm Gore-tex, determined by alternate assignment, and sutured with continuous 4-0 Gore-tex. Adhesion formation was graded at necropsy and recorded photographically in each animal. The mean adhesion index (none = 0, maximal = 4) was 1.37 +/- 0.12 and 2.62 +/- 0.12 (mean +/- SEM) for Gore-tex and Marlex groups respectively (p less than 0.005, unpaired t-test). A template was used to fashion 2-cm coronal strips of abdominal wall for tensile-strength testing. The relative strengths were 2.67 +/- 0.14 and 3.02 +/- 0.16 kg/cm (mean +/- SEM) for the Gore-tex and Marlex groups respectively (NS). Histologically, there were more epithelioid giant cells and less collagen formation in the Gore-tex group. Abdominal wall reconstruction with Gore-tex resulted in wound strength equal to that of Marlex and fewer adhesions. Gore-tex is preferred when prosthetic material and viscera are in close proximity.

The use of endoscopy after gastric partitioning for morbid obesity

Fiberoptic endoscopy is an important diagnostic modality for evaluating the patient with upper gastrointestinal tract symptoms following gastric restrictive operations. The specific indications for endoscopy after obesity surgery include stoma evaluation in patients who fail to lose adequate weight; stomal stenosis; esophagitis; surveillance of the excluded pouch; and suspicion of a marginal ulcer after gastric bypass.

Nonoperative management of stomal stenosis after gastroplasty for morbid obesity

Over a period of six years, 33 of 172 (19 per cent) patients who had gastric partitioning had stomal stenosis develop which was defined as an inability to drink fluids or swallow saliva, or both. All were managed conservatively in the hospital or on an outpatient basis. This consisted of total parenteral nutrition and endoscopy to evaluate the stoma with or without dilation; Eder-Puestow dilaters and long term jejunostomy feeding were used. Thirteen of these patients were dilated a total of 36 times. Three required three to six dilations each, up to the maximum size (45F). There were no complications. Twenty-nine required repletion by combined parenteral and enteral nutrition. Three required jejunostomy insertion as a separate procedure. Patients were observed for six to 60 months. Thirty-two did well. Gastrogastrostomy was required in one patient with a stenosis after the second gastroplasty. Three patients who were dilated regained over 20 per cent of their ideal weight.

Serum alanine aminotransferase to aspartate aminotransferase ratio and degree of fatty liver in morbidly obese patients

We evaluated the change in serum alanine aminotransferase (ALT; EC 2.6.1.2) to serum aspartate aminotransferase (AST; EC 2.6.1.; ALT/AST) ratio with the degree of fatty liver in morbidly obese patients. A total of 31 patients were included in the study. Fatty liver was graded as 0 to 4+. The mean and SD of AST and ALT were not significantly different between groups of patients with various grades of fatty liver. There was, however, a significant correlation between the ALT/AST ratio and the degree of fatty infiltration of the liver. This, we believe, implies damage mainly to the plasma membrane allowing loss of cytoplasmic enzymes rather than loss of mitochondrial enzymes.

Prevention of superficial phlebitis during peripheral parenteral nutrition

Fifty-four patients receiving peripheral parenteral nutrition consisting of 3.5 percent amino acids in a 5 percent dextrose solution were randomly assigned in a double-blind fashion to receive this solution with or without an antiphlebitic mixture (1000 IU heparin, 5 mg hydrocortisone, and 1.8 mEq sodium hydroxide as a buffer). The addition of antiphlebitic mixture resulted in a marked and highly significant reduction in the incidence of phlebitis and a prolongation of the number of phlebitis-free hours during infusion of peripheral parenteral nutrition (p less than 0.005).

Long-term follow-up of concomitant band ligation and sclerotherapy for internal hemorrhoids

From 1978 to 1983, 111 patients with symptomatic internal hemorrhoids were treated as outpatients by a modification of the Barron ligation technique. Each ligated hemorrhoid was injected with a sclerosant. Follow-up, available for 94 of the patients, ranged from 2 to 60 months (mean 18 months). Presenting symptoms were bleeding in 75 (80%) of the 94 patients, pain in 46 (49%), pruritus in 22 (23%) and prolapse in 24 (26%). Results were excellent in 51 (54%) patients, good in 20 (21%) and fair in 9 (10%). Fourteen (15%) patients had unsatisfactory results; only 4 of these required hemorrhoidectomy. The other 10 had residual symptoms but did not require further treatment. Nine patients had minor complications, which included pain lasting 24 to 72 hours in seven, bleeding in one and syncope in one. The addition of sclerotherapy to traditional band ligation for the management of internal hemorrhoids has the advantages of exciting a greater inflammatory reaction between the mucosa and submucosa and preventing premature slipping of the band. The authors conclude that this method of therapy is effective for symptomatic hemorrhoids and that surgical hemorrhoidectomy is seldom indicated.

Rate of weight loss after vertical banded gastroplasty in morbid obesity: relationship to serum lipids and uric acid

The relationship between postoperative weight loss after vertical banded gastroplasty in morbidly obese patients and preoperative serum triglycerides, cholesterol, HDL-cholesterol, uric acid and fasting plasma glucose was evaluated. The rate of weight loss, calculated as a percentage of original weight, was determined at three and six months after surgery. There was a significant correlation between rate of weight loss at three months and preoperative serum uric acid (r = -0.60, p less than 0.01). and also with the total cholesterol: HDL-cholesterol ratio (r = 0.61, P less than 0.01). At six months, the rate of weight loss correlated with preoperative serum triglycerides (r = -0.54, p less than 0.02) and total cholesterol: HDL cholesterol ratio (r = 0.44, p less than 0.05). The reasons for the predictive value of these biochemical parameters is unknown and deserves further study.

Vertical banded gastroplasty: assessment of efficacy

We previously demonstrated unacceptably high failure rates with horizontal gastroplasty. Shortly thereafter, vertical banded gastroplasty was introduced. Since April 1982 we have operated on 56 patients who were carefully selected and closely followed. There were 10 men and 46 women, aged 15 to 54 years (mean age 36 years) with preoperative weights of 93.5 to 198.6 kg (mean 125.9 kg). The mean weight loss at 6 to 12 months was 36 +/- 10 kg, or 30% of body weight. At 18 months, data were available for 48 of the 56 patients. Their weight losses were 44 +/- 11 kg, or 35% of body weight. Eight patients were lost to follow-up. The weight of nine additional patients plateaued before they lost 30% of their starting weights and another eight patients have started to regain weight after achieving satisfactory weight loss. Included are two patients with severe stenoses who regained all weight lost.

Colonization of intravascular monitoring devices

This randomized prospective study of all invasive catheters inserted in our ICU tested the hypothesis that daily dressing changes would reduce the 25% infection rate associated with these catheters. Significant growth was noted in eight (7%) of 133 vs. nine (6.7%) of 135 skin cultures from patients whose dressings and infusion tubings were changed at 24 vs. 72 h, respectively. Catheter tip cultures were positive in six (5.9%) of 102 vs. eight (7.5%) of 107 for the 24- and 72-h groups, respectively. Paradoxically, blood cultures were positive in three (6.7%) of 45 vs. 12 (23.1%) of 52 from the 24- and 72-h groups, respectively (p less than .03). However, there was no correlation between the positive blood cultures and the organisms cultured from the catheter tips.

Relationship between body weight and total leukocyte count in morbid obesity

The authors studied the relationship between total leukocyte count and body weight in 42 morbidly obese patients (weight range, 101.5-206.8 kg). None of the patients had a recent history of infection, hematologic disorders, chronic respiratory disease, or were smoking more than 5 cigarettes/day. The range of total leukocyte count was 4.2-12.0 X 10(9) cells/L. Twelve of the 42 patients had a leukocyte count of 10 X 10(9) cells/L. There was a significant correlation between body weight (kg) and total leukocyte count (r = 0.68, P less than 0.001). Morbid obesity should be considered as one of the causes of physiologic leukocytosis.

Colonization of intravascular catheters in the intensive care unit

A prospective study of intravascular catheters (arterial, Swan-Ganz, and central venous) in two hospitals with similar intensive care units revealed an overall 25 percent colonization rate (more than 15 colony counts). Arterial catheters had the lowest colonization rate and central venous catheters had the highest. Arterial, Swan-Ganz, and central venous catheters are possible sources of nosocomial infections and septicemia. They should be inserted only when necessary. A critical review of our data and the literature suggests that future studies should examine the potential benefits of assiduous insertion technique, improved dressing care, intravascular delivery systems, and the choice of catheter.

Preventing superficial phlebitis during infusion of crystalloid solutions in surgical patients

Thirty patients who received routine intravenous therapy (3.3% dextrose and 0.3% normal saline at a rate of 100 mL/h) were randomized prospectively into two groups to receive an antiphlebitic mixture of heparin-hydrocortisone-sodium bicarbonate or placebo in a double-blinded fashion for 4 to 7 days. The code was then broken and the data were analysed using chi 2 analysis with respect to the clinical grade and incidence of phlebitis. Phlebitis developed in 2 of 14 study and 10 of 16 control patients. All study patients tolerated their intravenous lines longer and needed less restarting. The antiphlebitic mixture effectively prevented superficial infusion phlebitis in patients receiving dextrose-saline solutions.

Gastric by-pass surgery in morbidly obese patients markedly decreases serum levels of vitamins A and C and iron in the peri-operative period

We studied changes in serum levels of carotene, vitamins A, C, B12 and folate and iron in the immediate perioperative period after gastric by-pass surgery in nine morbidly obese patients and in six patients undergoing abdominal surgery. All parameters were measured preoperatively and 48 h postoperatively. Marked decreases occurred for vitamin A (2.04 +/- 0.45 mumol/l to 0.92 +/- 0.39 mumol/l, P less than 0.01), vitamin C (26 +/- 11.2 mumol/l to 4.9 +/- 4.0 mumol/l, P less than 0.01), iron (15 +/- 5.8 mumol/l to 4 +/- 2.7 mumol/l, P less than 0.01). A significant change also occurred for carotene (1.7 +/- 0.42 mumol/l to 1.25 +/- 0.48 mumol/l, P less than 0.05). No significant changes were seen for vitamins B12 and folate. Only changes in vitamins A and C were significantly greater in the morbidly obese patients compared to the control group of six patients. These changes likely represent redistribution of vitamins rather than enhanced urinary excretion.

Clinical comparison of Michel and Proximate clips used for abdominal wound closure

For many years Michel clips (Down Surgical, Mississauga, Ont.) have been used to close wounds and results have been good, but several newer clips are now available (e.g., Proximate; Ethicon Sutures Ltd.), which are said to be easier to use and produce a better scar. However, they are much more expensive. The authors carried out a prospective controlled study in which 30 patients with abdominal incisions had half of the skin incision closed with Michel clips and the other half with Proximate clips. They assessed ease of insertion and removal, and appearance of the wound immediately after removal and 2 months later. Ethicon Proximate clips were, in general, slightly easier to insert, less uncomfortable to remove in 8 of the 30 patients and gave a better immediate cosmetic result in 9 patients. However, there was no difference in the appearance of the wound 2 months later. The authors do not consider that Ethicon Proximate clips offer an advantage over the much less expensive Michel clips.

Healing of a gastrocutaneous fistula in the presence of Marlex

A gastric leak with perigastric abscesses developed after a revision gastroplasty reinforced with Marlex, performed on a 34-year-old, morbidly obese woman. The site of the leak and the abscesses were drained but the Marlex could not be excised. The woman remained on long-term enteral nutrition at home and her fistula healed despite the presence of the Marlex mesh. She continued to lose weight and was well 8 months after the fistula had healed.

Safety and efficacy of a new peripheral intravenously administered amino acid solution containing glycerol and electrolytes

A multicenter study was conducted to compare a new peripheral intravenously given solution containing 3 per cent amino acids, 3 per cent glycerol and a complete pattern of maintenance electrolytes--ProcalAmine--with an isonitrogenous amino acid control solution--FreAmine III--in patients undergoing elective gastrointestinal or vascular operations. Fifty-two patients received the control solution and 48 patients received the experimental solution in a double-blind, randomized trial for five consecutive postoperative days. A complete hematologic and biochemical assessment was carried out daily throughout the five day infusion period and two days after the termination of infusion. Nitrogen balance data were collected on each infusion day. Results indicate that the glycerol containing solution is safe and contributes to an improvement in nitrogen homeostasis on a daily and cumulative basis. The presence of ketosis was not related to an improvement in nitrogen balance. In conclusion, the addition of glycerol to dilute amino acid solutions is safe and improves nitrogen balance in the postoperative period. Additionally, use of the nonreducing sugar, glycerol, allows the manufacturer to sterilize amino acids and an energy substrate in a single unit. By precluding the need for admixing in the hospital pharmacy, risk of contamination may be reduced.

A study of the percutaneous absorption from topically applied zinc oxide ointment

The systemic absorption from topical applications of 40% zinc oxide ointment was investigated in a series of healthy subjects (phase one) and in patients receiving total parenteral nutrition (phase two). In the first phase, six subjects completed a controlled, cross-over trial involving 3 hourly serum sample determinations for zinc concentration following a massive application of 40% zinc oxide ointment and plain petrolatum ointment. There was a mean increase in serum zinc from 107.3 +/- 5.32 to 116.1 +/- 5.02 micrograms/dL 1 hr after application of 40% zinc oxide ointment (p greater than 0.05). Three patients receiving total parenteral nutrition completed phase two of the protocol in which 40% zinc oxide ointment was applied daily to a specified area of the thigh. Analysis of these patients' serum revealed that the zinc concentrations remained relatively constant over the 10-day study period. These findings suggest that topical applications of 40% zinc oxide ointment do not result in significant absorption. This study serves as a starting point for further investigations.

Failure rate with gastric partitioning for morbid obesity

One hundred twenty-two morbidly obese patients were selected for gastric partitioning from a multidisciplinary obesity clinic over a 4 year period. Initial early success was not a guarantee against cessation of weight loss or the regaining of lost weight. By emphasizing criteria for success and failure, both from our series and the literature, we showed an alarming increase in the failure rates for this procedure which is predicated on the fact that those lost to follow-up were probably failure patients. Numerous articles in the literature contain inadequate data because they refer to pounds rather than percentage of weight loss, they fail to consider revisions as failures, they do not provide 24 month follow-up data, and they do not take into account the possibility that those lost to follow-up are failure patients. The operation carries mortality and serious morbidity rates of 0 to 3 percent and 4 to 10 percent, respectively, with an average 28 percent weight loss at 24 months and a minimal failure rate of 50 percent. The alarming increase in the number of these procedures being carried out across the continent makes it mandatory for surgeons to accurately collect and register their data until the long-term effects and results are known. Gastric partitioning, although probably not experimental, is still developmental. The widespread use and possibly abuse of these operations may result in discreditation of the surgical approach to morbid obesity which would be unfortunate since it is the only practical method at this time for dealing with the problem.

Use of glycerol in peripheral parenteral nutrition

Peripheral parenteral nutrition avoids the use of central lines and is a useful means of nutritional support for selected patients. Amino acids alone have been used for peripheral parenteral nutrition and have been shown to give near nitrogen equilibrium. The addition of small amounts of dextrose to amino acids further improves nitrogen balance, but at the expense of making the solutions unsterilizable and unstable by standard techniques. Glycerol is a nonprotein calorie source that can be autoclaved with amino acids and stored. Fasting patients about to undergo major abdominal surgery were randomly allocated to receive 3% amino acids with or without 3% glycerol. The solution was infused by peripheral vein for 5 days, starting the morning following surgery. Routine monitoring, blood tests, and nitrogen balance tests were performed during this time. No adverse reactions to either solution were encountered. Liver function tests, electrolytes, and hematologic values were similar in both groups. The cumulative nitrogen balance was better in the amino acid plus glycerol group (+5 +/- 3.3 gm) than in the amino acid group (-9.7 +/- 3 gm) (P less than 0.02). Serum insulin levels were higher and serum free fatty acids lower in the amino acid plus glycerol group. Glycerol levels rose and plateaued by the third day in the amino acid plus glycerol patients. Amino acids plus glycerol is safe solution to administer by peripheral vein. The addition of glycerol improves nitrogen balance as compared to amino acids alone.

Effects of magnesium infusions on magnesium and nitrogen balance during parenteral nutrition

The effects of magnesium infusions on urinary and fecal magnesium excretion, serum magnesium and nitrogen balance were examined in seven well-nourished and three nutritionally depleted adult surgical patients receiving total parenteral nutrition. They were maintained on constant nitrogen and caloric intake for 14 +/- 2 days. Magnesium doses ranged from 0 to 664 mg/d and were given in varying crossover patterns. In both groups, urinary magnesium excretion increased as the amount of magnesium infused increased but, at comparable magnesium infusions, depleted patients excreted significantly less magnesium. Renal conservation was most pronounced in well-nourished patients on magnesium-free intake and in depleted patients given 70 mg magnesium daily. Urinary magnesium losses were 40 +/- 5 mg/d and 33 +/- 8 mg/d, respectively, in these two groups. Endogenous fecal magnesium excretion was minimal and ranged from 2 to 38 mg/d. At each level of magnesium intake, serum levels of well-nourished patients were normal. With infusions of less than 200 mg/d, serum magnesium concentrations in depleted subjects averaged 1.6 mg/dl. Reduced urinary magnesium excretion as well as borderline serum levels measured in depleted adults suggest that the magnesium dosage should be higher than that usually recommended during total parenteral nutrition. In both groups a positive correlation between magnesium and nitrogen balance was noted.

The radiology of gastroplasty for morbid obesity

From experience with 101 patients, the radiologic features of gastroplasty for the surgical treatment of morbid obesity are described. Prompt recognition of surgical complications requires familiarity with expected postoperative appearances. Early complications are: (a) gastric leak with subphrenic abscess, (b) stomal edema and (c) staple dehiscence. Failure to continue to lose weight after surgery results from stretching of the pouch and/or stoma, or delayed staple disruption, due to persistent over-eating.

Feeding jejunostomy under local anesthesia

A feeding jejunostomy may be performed with ease and safety under local anesthesia. The authors describe their technique. The tube is easy to maintain and replace and avoids some of the problems of feeding gastrostomies. In patients with major nutritional problems and a functioning intestinal tract the need for parenteral nutrition may be eliminated.

Parenteral nutrition by peripheral vein

Peripheral parenteral nutrition can provide perioperative nutritional support to patients with inadequate oral intake in whom total parenteral nutrition with hypertonic dextrose administered by a central vein cannot be undertaken because of sepsis, subclavian vein thrombosis, or lack of expertise and familiarity. Peripheral parenteral nutrition may be indicated in patients with marginal nutritional status whose postoperative course and period of starvation are unpredictable and in patients being started on a total enteral nutrition regimen. In patients with increased requirements because of stress or malnutrition who need full nutritional support by a peripheral method, the lipid system is indicated. In certain instances, large enough volumes can be infused to provide sufficient calories and protein for nutritional repletion. Protein-sparing therapy is indicated for nutritional maintenance in patients who do not clearly require full support by total parenteral nutrition but who are taking insufficient calories and protein orally. Peripheral parenteral nutrition avoids the risks of subclavian vein catheterization but requires that adequate peripheral veins are available. The metabolic complications are minimal compared with those of total parenteral nutrition, and the nutritional management of the diabetic patient is greatly simplified. Several techniques of preserving peripheral veins and prolonging their use have been discussed.