Translational value of preclinical models for renal denervation: a histological comparison of human versus porcine renal nerve anatomy

BACKGROUND

Preclinical models have provided key insights into the response of local tissues to radiofrequency (RF) renal denervation (RDN) that is unobtainable from human studies. However, the anatomic translatability of these models to the procedure in humans is incompletely understood.  Aims: We aimed to compare the renal arterial anatomy in normotensive pigs treated with RF-RDN to that of human cadavers to evaluate the suitability of normotensive pigs for determining the safety of RF-RDN.

METHODS

Histopathologic analyses were performed on RF-treated renal arteries in a porcine model and untreated control renal arteries. Similar analyses were performed on untreated renal arteries from human cadavers.  Results: In both human and porcine renal arteries, the median number of nerves was lower in the more distal sections (the numbers in the proximal, middle, distal, 1st bifurcation, and 2nd bifurcation sections were 65, 58, 47, 22.5, and 14.7 in humans, respectively, and 39, 26, 29, 16.5, and 9.3 in the porcine models, respectively). Renal nerves were common in the regions between arteries and adjacent veins, but only 3% and 13% of the renal nerves in humans and pigs, respectively, were located behind the renal vein. The semiquantitative score of RF-induced renal arterial nerve necrosis was significantly greater at 7 days than 28 days (0.98 vs 0.75; p=0.01), and injury to surrounding organs was rarely observed.

CONCLUSIONS

The distribution of nerve tissue and the relative distribution of extravascular anatomic structures along the renal artery was similar between humans and pigs, which validates the translational value of the normotensive porcine model for RDN.

Patient-driven hand hygiene audit process at a regional cancer center

A patient-driven hand hygiene compliance audit strategy was piloted in a Canadian provincial cancer agency during routine provision of cancer outpatient care by health care providers (physicians, nurses, and health care aides) under conditions where the deployment of an independent external auditor was not feasible. The results of the audit suggest the feasibility of this approach as a routine institutional performance metric.

Outcome of local excision of rectal carcinoma

PURPOSE

This study was designed to determine the results of patients with rectal adenocarcinoma treated with local excision.

METHODS

A retrospective, chart review was conducted for all patients treated with local excision for rectal adenocarcinoma from 1984 to 1998.

RESULTS

Sixty-four patients were retained for analysis. The median follow-up was 37 (range, 9-125) months. There were 15 local failures with a median time to local failure of 12 months. Seven patients were salvaged with further operation (4 by repeat local excision, 4 by abdominoperineal resection, and 1 by low anterior resection). The incidence of local recurrence increased with advancing stage of the carcinoma (T1, 13 percent; T2, 24 percent; T3, 71 percent), histologic grade of differentiation, (well, 12 percent; moderately, 24 percent; poorly, 44 percent), and margin status (negative, 16 percent; close (within 2 mm), 33 percent; positive, 50 percent). Sixteen percent of carcinomas < or = 3 cm failed compared with 47 percent for carcinomas > 3 cm. Nine percent (1/11) of T2 patients treated with adjuvant radiation therapy recurred locally compared with 36 percent (5/14) without radiation therapy. Three of four T3 patients who received radiation therapy failed locally compared with two of three who did not. Using the Kaplan-Meier method, the overall survival at five years was 71 percent, and disease-free survival was 83 percent. Actuarial local failure was 27 percent and freedom from distant metastasis was 86 percent. The sphincter preservation rate was 90 percent at five years.

CONCLUSIONS

Local excision alone is an acceptable option for well-differentiated, T1 carcinomas, < or = 3 cm. Adjuvant radiation is recommended for T2 lesions. The high local recurrence rate in patients after local excision of T3 lesions with or without adjuvant radiotherapy would mandate a radical resection.

Assessment of the cytotoxicity of photocrosslinked dextran and hyaluronan-based hydrogels to vascular smooth muscle cells

The cytotoxicity of polysaccharide-based hydrogels and solutions was studied in vitro after 48h of indirect exposure of the materials with vascular smooth muscle cells. Dextran and/or hyaluronan were derivatized using glycidyl methacrylate, and hydrogels were formed in the presence of photoinitiators and ultraviolet radiation in multiwell inserts to avoid direct contact with cell monolayers. Observation of cell morphology indicated that dextran hydrogels, a blend of non-derivatized hyaluronan into dextran hydrogel. and a hyaluronan solution were highly cytocompatible. However, hydrogels made of derivatized hyaluronan were cytotoxic when compared to unexposed sham controls that contained multiwell inserts but no hydrogels. Results from quantitative assays for proliferation and viability corroborated the qualitative observations, and scrape wound assays revealed a significant increase in smooth muscles cell migration/proliferation after indirect exposure to several of the polysaccharide-based materials. Results from this study demonstrate that hydrogels made of dextran and hyaluronan solution show good cytocompatibility in vitro. making these degradable matrices interesting candidates for drug delivery purposes.

Seven principles for teaching procedural and technical skills

The authors developed a cognitive-theory-based checklist of seven important principles for teaching technical skills. They then used the checklist in a workshop for doctors who teach procedural and technical skills. Participants in the workshop found the principle-based approach to be more effective than the traditional "see one, do one, teach one" approach.

Quality of life after coronary revascularization in the United States and Canada

Cardiac procedures are performed less frequently in Canada than in the United States (US), yet rates of cardiac death and myocardial infarction are similar. We therefore sought to compare long-term symptoms and quality of life in Canadian and American patients undergoing initial coronary revascularization. The 161 patients enrolled in the Bypass Angioplasty Revascularization Investigation at the Montreal Heart Institute were compared with 934 patients enrolled at 7 US sites. Patients' outcomes were documented for 5 years after random assignment to percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery. Functional status was assessed using the Duke Activity Status Index. Canadian patients were significantly younger and had more angina at study entry. Death and nonfatal myocardial infarction were not significantly different between Canadian and US patients after adjustment for baseline risk. Canadian patients had significantly greater improvements in functional status at 1-year follow-up (Duke Activity Status Index score + 13.5 vs. + 6.0, p = 0.002), but this difference progressively narrowed over 5 years. Angina was equally prevalent in Canadian and US patients at 1 year (16% vs. 19%), but significantly more prevalent in Canadian patients at 5 years (36% vs. 16%, p = 0.001). Repeat revascularization procedures were performed less often over 5 years among Canadian patients (26% vs. 34%, p = 0.08), especially coronary artery bypass graft surgery after initial percutaneous transluminal coronary angioplasty (18% vs. 32%, p = 0.03). These results suggest more anginal symptoms are required in Canada before coronary revascularization, but as a result Canadians receive greater improvements in quality of life after the procedure.

Ileoanal anastomosis with reservoirs: complications and long-term results

OBJECTIVE

To determine the rate of complications of ileoanal pouch anastomosis, their treatment and their influence on a successful outcome.

DESIGN

A computerized database and chart review.

SETTING

Three academic tertiary care health centres.

PATIENTS

All 239 patients admitted for surgery between 1981 and 1994 with a diagnosis of ulcerative colitis and familial adenomatosis coli.

INTERVENTIONS

Sphincter-saving total proctocolectomy and construction of either S-type of J-type ileoanal reservoir.

OUTCOME MEASURES

Indications, early and late complications, incidence of pouch excision.

RESULTS

Of the 239 patients, 228 (95.4%) were operated on for ulcerative colitis and 11 (4.6%) for familial polyposis coli. One patient in each group was found to have a carcinoma not previously diagnosed. Twenty-eight patients had poor results: in 17 (7.1%) the ileostomy was never closed or was re-established because of pelvic sepsis or complex fistulas, sclerosing cholangitis or severe diarrhea; 11 (4.6%) patients required excision of the pouch because of anal stenosis, perirectal abscess-fistula or rectovaginal fistula. Three patients died--of suicide, and complications of liver transplantation and HIV infection. Thus, 208 patients maintained a functioning pouch. The early complication rate (within 30 days of operation) was 57.7% (138 patients) and the late complication rate was 52.3% (125 patients). Pouchitis alone did not lead to failure or pouch excision. Emptying difficulties in 25 patients with anal stenosis were helped in 2 by resorting to intermittent catheterization. Patients with indeterminate colitis had a higher rate of anorectal septic complications, and all patients having Crohn's disease after pouch construction had complicated courses.

CONCLUSIONS

The complication rate associated with ileoanal pouch anastomosis continues to be relatively high despite increasing experience with this technique. Overall, however, a satisfactory outcome was obtained in 87% of patients.

Some thaumatin-like proteins hydrolyse polymeric beta-1,3-glucans

Thaumatin and 12 purified thaumatin-like (TL) proteins were surveyed for their capacity to hydrolyse beta-1,3-glucans by using an in-gel glucanase assay. Six TL proteins identified by N-terminal amino acid microsequencing were found to be active on carboxymethyl(CM)-pachyman: a barley leaf stress-related permatin, two tomato fruit osmotins, a cherry fruit and two tobacco stigma proteins. TL enzymes ranged in specific activity from 0.07 to 89 nkat mg-1 with CM-pachyman as substrate. Hydrolytic activities were not restricted to TL proteins strongly binding to water-insoluble beta-1,3-glucans since the two osmotins were active without tight binding to pachyman. Some TL proteins hydrolysed crude fungal walls and one barley TL enzyme even lysed fungal spores. No activity was observed on laminarin in the in-gel hydrolase assay. Thin-layer chromatography revealed that the six enzymes acted as endo-beta-1, 3-glucanases leading to the formation of various oligoglucosides. Thus far, the TL enzymes (EC 3.2.1.x) appeared different from the well-known beta-1,3-glucanases (EC 3.2.1.39). No activity was found with thaumatin, zeamatin, tobacco leaf PR-R protein and four stress-related TL proteins from barley and pea. This is the first demonstration that diverse TL proteins are enzymatically active. The functions of some TL proteins must be reassessed because they display endo-beta-1,3-glucanase activity on polymeric beta-1, 3-glucans.

Several thaumatin-like proteins bind to beta-1,3-glucans

Pathogenesis-related proteins from intercellular fluid washings of stressed barley (Hordeum vulgare L.) leaves were analyzed to determine their binding to various water-insoluble polysaccharides. Three proteins (19, 16, and 15 kD) bound specifically to several water-insoluble beta-1,3-glucans. Binding of the barley proteins to pachyman occurred quickly at 22 degreesC at pH 5.0, even in the presence of 0.5 M NaCl, 0.2 M urea, and 1% (v/v) Triton X-100. Bound barley proteins were released by acidic treatments or by boiling in sodium dodecyl sulfate. Acid-released barley proteins could bind again specifically and singly to pachyman. Water-soluble laminarin and carboxymethyl-pachyman competed for the binding of the barley proteins to pachyman. The N-terminal sequence of the 19-kD barley beta-1,3-glucan-binding protein showed near identity to the barley seed protein BP-R and high homology to other thaumatin-like (TL) permatins. The 16-kD barley protein was also homologous to TL proteins, whereas the 15-kD barley protein N-terminal sequence was identical to the pathogenesis-related Hv-1 TL protein. Antifungal barley protein BP-R and corn (Zea mays) zeamatin were isolated by binding to pachyman. Two extracellular proteins from stressed pea (Pisum sativum L.) also bound to pachyman and were homologous to TL proteins.

Detection of enzymes active on various beta-1,3-glucans after denaturing polyacrylamide gel electrophoresis

Enzymes were assayed for glucanase activity after denaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in gels containing beta-1,3-glucans embedded as substrate. Lentinan, curdlan, paramylon, baker's yeast alkali-insoluble glucan, baker's yeast alkali-soluble glucan and carboxymethyl (CM)-pachyman were compared to oligomeric laminarin, which is the usual substrate for assaying beta-1,3-glucanase activities. Detecting enzyme activities by aniline blue fluorescent staining was also compared with the staining of released reducing sugars by 2,3,5-triphenyltetrazolium chloride (TTC). For the nonreduced proteins, the Driselase extract exhibited one major band at 32.5 kDa and one less intense band at 23 kDa for most substrates with the two detection procedures. No Lyticase enzyme was detected in either detection procedures for all tested substrates. For barley enzymes, no activity was revealed after aniline blue staining while one undescribed 19 kDa glucanase activity was best shown after TTC staining with curdlan, paramylon and CM-pachyman as substrates. In the case of reduced proteins, the Lyticase extract yielded three bands (33, 36 and 46 kDa) on several substrates with both detection procedures. This was the same for the barley leaf extract (32, 36 and 39 kDa). The Driselase extract showed one 42 kDa band. Many enzymes active on beta-1,3-glucans are thus best revealed when proteins are denatured and reduced and when protein renaturation after SDS-PAGE involves a pH 8.0 treatment and the inclusion of 1 mM cysteine in buffers. However, some enzymes are only detected when proteins are denatured without reduction. Finally, the use of various polymeric beta-1,3-glucan substrates different from oligomeric laminarin is necessary to detect new types of enzymes such as the 19 kDa barley glucanase.

Lipid uptake by silicone enteral access feeding devices

BACKGROUND/PURPOSE

Deterioration of long-term enteral access devices remains a significant patient care and financial problem. Because it is known that lipids, particularly medium-chain triglycerides oil (MCT oil), can soften and break certain types of polymeric materials, the authors evaluated the effect of liquid enteral feeding formulas containing different amounts of MCT oil on silicone feeding tubes.

METHODS

Commercially available and widely used gastrostomy silicone catheters of two sizes (20F and 15F) were sectioned in 5-cm-long samples and cleaned. Five groups of five pieces were immersed for 8 weeks in pure MCT oil and in four commercial formulas having similar protein, carbohydrate, and fat contents. These formulas were chosen because they contained similar percentages of fat (37% to 45%), although they contained differing amounts of MCT oil. Sodium azide 0.05% was added as a bactericide. Samples were maintained at 37 degrees C in an incubator-shaker. After incubation, specimens were rinsed, dried, and weighed. Selected samples were extracted with a chloroform-methanol solution (2:1). Super-critical fluid chromatography (SFC) and infrared (IR) spectroscopy were performed. A tensile tester was used to generate force-elongation curves for the remaining samples. A statistical analysis (ANOVA, alpha = .05) was conducted to compare data from test groups with results from 20 samples of control silicone material.

RESULTS

Data demonstrate that silicone is significantly affected by liquid formulas and pure MCT oil. SFC and IR findings indicated that fractions of MCT oil, corn oil, and canola oil were absorbed by the material. The most dramatic weight gain (3.7%) was observed for specimens immersed in pure MCT oil. An average increase (9.6%) of silicone compliance was measured along with oil migration in the tubing.

CONCLUSIONS

Lipid uptake contributes significantly to deterioration of the silicone tested, leading to device failure. Surface damage can create a potential nidus for microorganisms, particularly fungi. Lipid type and rate of administration should be taken into account when long-term enteral feedings are given. These data contribute to the understanding of the causes of the physico-chemical deterioration of long-term enteral feeding devices and provide helpful information for the design and manufacture of improved products.

Long-term prognostic value of clinically evident noncoronary vascular disease in patients undergoing coronary revascularization in the Bypass Angioplasty Revascularization Investigation (BARI)

In the general population, peripheral atherosclerosis is a strong predictor of cardiovascular disease and death. In patients with known coronary artery disease, it is unclear whether the presence of additional noncoronary atherosclerosis is of further prognostic value. In the Bypass Angioplasty Revascularization Investigation, 5-year outcome was compared between patients with and without clinically evident noncoronary atherosclerosis. Within the subgroup with noncoronary atherosclerosis, surgery, and angioplasty treatment strategies were compared. Noncoronary atherosclerosis was defined as claudication, peripheral vascular surgery, abdominal aortic aneurysm, history of cerebral ischemia, or carotid disease. Among 1,816 patients, 303 (17%) had noncoronary atherosclerosis. These patients were more likely to have a history of congestive heart failure, diabetes, and hypertension, and were more likely to smoke. Coronary angiographic variables were similar between the 2 groups. Five-year survival was 75.8% for patients with noncoronary atherosclerosis and 90.2% for those without (p < 0.001). The adjusted relative risk of death was 1.7 for any noncoronary atherosclerosis, 1.5 for lower extremity disease alone, 1.7 for cerebral disease alone, and 2.3 for both conditions. Among the 303 patients with noncoronary atherosclerosis, the adjusted relative risk of death for surgery versus angioplasty was 0.87 (p = 0.40). However, the study has limited power to detect a treatment effect in this small subgroup. Thus, patients with combined coronary and clinically evident noncoronary atherosclerosis are a high-risk group with significantly worse long-term outcome compared patients with isolated coronary disease.

Communication during the recruitment phase of a multicenter trial: the recruitment hotline

The Bypass Angioplasty Revascularization Investigation (BARI) is a randomized trial that compares the safety and efficacy of angioplasty and bypass surgery in selected patients with multivessel coronary disease. During recruitment, the Clinical Coordinating Center (CC) required an organized manner of responding to the many questions expected from the 18 clinical sites. Thus a dedicated telephone line was established to provide the clinical sites with information quickly and ensure consistent dissemination of information. In addition, the hotline functioned as a backup mechanism for patient randomization in the event of a computer failure at one of the sites. During the first 13 months of recruitment, 1332 calls were received. The average number of daily calls peaked at 7.3 with 14 calls being the highest in any one day. Calls gradually declined as the clinical sites became more familiar with the protocol, data collection forms, and computer systems. Most questions were answered by the data management staff; however a substantial number (37%) required faculty level input. For questions that could not be answered immediately, the median time for a return call was 25 min. The BARI hotline was an efficient way to provide accurate and consistent feedback to all sites and to identify areas that required protocol clarification. It allowed rapid identification of differences in protocol interpretation across sites so that these variations could be addressed. Review of specific questions by the Operations Committee resulted in decisions on how to apply the protocol to particularly difficult or exceptional cases. While the system was labor-intensive, its benefits outweighed this disadvantage. Recommended modifications to lower costs would result in a system that could be easily adapted for use in other clinical trials.

Detection of a glycosylated form of hen egg white lysozyme

By assaying lysozyme activity after denaturing polyacrylamide gel electrophoresis of commercial hen egg white lysozyme preparations, minor lysozymal activity was detected as an 18-kDa protein. After electrophoretic purification for microsequencing, the N-terminus sequence of the 18-kDa lysozyme was found to be identical with mature 14.4-kDa hen egg white lysozyme. The 18-KDa hen egg white lysozyme was judged to be glycosylated based on 3.6-kDa decrease in molecular mass after N-glycosidase F treatment, binding to concanavalin A-Sepharose, and staining with periodate-Schiff's reagent. The minor form corresponded to about 0.3% of lysozyme molecules.

Cloning, sequencing, and expression in Escherichia coli of a Streptococcus faecalis autolysin

A Streptococcus faecalis genomic bank was obtained by partial digestion with MboI and cloning into the SalI restriction site of pTZ18R. Screening of about 60,000 Escherichia coli transformants for cell wall lysis activity was done by exposing recombinant colonies grown on medium containing lyophilized Micrococcus lysodeikticus cells to chloroform and toluene vapors in order to release proteins. Because this procedure provoked cell death, colonies could not be used directly for transformant recovery; however, recovery was achieved by partial purification of plasmid DNA from active colonies on the agar plate and transformation of E. coli competent cells. About 60 recombinants were found. One of them (pSH6500) codes for a lytic enzyme active against S. faecalis and M. lysodeikticus cell walls. A shorter clone (pSH4000) was obtained by deleting an EcoRI fragment from the 6.5-kb original insert, leaving a 4-kb EcoRI-MboI insert; this subclone expressed the same lytic activity. Sequencing of a portion of pSH4000 revealed a unique open reading frame of 2,013 nucleotides coding for a 641-amino-acid (74-kDa) polypeptide and containing four 204-nucleotide direct repeats.

Detection of chitin deacetylase activity after polyacrylamide gel electrophoresis

Mucor racemosus and Rhizopus nigricans were used as sources of chitin deacetylases. Crude protein extracts were subjected to polyacrylamide gel electrophoresis at pH 8.9 (Davis system) or 4.3 (Reisfeld system) under native conditions. After electrophoresis, an overlay gel containing 0.1% (w/v) glycol chitin as substrate was incubated in contact with the separation gel. Chitin deacetylase activity was revealed by uv illumination with a transilluminator after staining for 5 min in 0.01% (w/v) Calcofluor white M2R. Chitosan (deacetylated chitin) generated by chitin deacetylases appeared more fluorescent than the intact chitin embedded in the overlay gel. Chitosan in a separate overlay gel was also subjected to a nitrous acid treatment which specifically depolymerizes chitosan while leaving chitin intact. Hydrolysis of chitosan by nitrous acid followed by Calcofluor staining yielded dark (nonfluorescent) bands (chitin deacetylase activities) in the fluorescent chitin-containing gel. Both assays revealed the presence of several chitin deacetylases from Zygomycetes. The same assays were performed after denaturing electrophoresis in 12% (w/v) polyacrylamide gels containing 0.1% (w/v) glycol chitin. Enzymes were renatured in buffered 1% (v/v) purified Triton X-100. Chitin deacetylases with estimated molecular weights between 26,000 and 64,000 were detected after Calcofluor staining. The assays were also performed in two-dimensional gel electrophoretic systems. Chitin deacetylases can be rapidly revealed by using the assay involving the nitrous acid treatment. However, both assays (with and without nitrous acid treatment) should be run to conclusively demonstrate chitin deacetylase activity after polyacrylamide gel electrophoresis.

Detection of beta-1,3-glucanase activity after native polyacrylamide gel electrophoresis: application to tobacco pathogenesis-related proteins

Beta-1,3-Glucanase (laminarinase) activity was detected after polyacrylamide gel electrophoresis under native conditions by using laminarin as substrate. Following incubation of gels, laminarin was stained with Aniline Blue. Under UV illumination, lysis zones appeared as dark bands against a fluorescent background. As low as 0.001 unit of commercial Penicillium laminarinase could be observed after incubating the polyacrylamide gel for 45 min at pH 5.0. Extracts of commercial Penicillium laminarinase exhibited four bands with lytic activity towards laminarin. Analysis of intercellular fluid extracts of tobacco mosaic virus-infected tobacco leaves revealed four beta-1,3-glucanases corresponding to three acidic pathogenesis-related proteins, b4 (2), b5 (N) and b6b (0), and one basic protein. The presence of laminarin in gels retarded the migration of some proteins with beta 1,3-glucanase activity. This change in electrophoretic mobility could be used as a complementary affinity test for identifying proteins with beta-1,3-glucanase activity.

Detection of chitinase activity after polyacrylamide gel electrophoresis

Commercial Streptomyces griseus and Serratia marcescens chitinases and purified wheat germ W1A and hen egg white lysozymes were subjected to polyacrylamide gel electrophoresis under native conditions at pH 4.3. After electrophoresis, an overlay gel containing 0.01% (W/V) glycol chitin as substrate was incubated in contact with the separation gel. Lytic zones were revealed by uv illumination with a transilluminator after staining for 5 min with 0.01% (W/V) Calcofluor white M2R. As low as 500 ng of purified hen egg lysozyme could be detected after 1 h incubation at 37 degrees C. One band was observed with W1A lysozyme and several bands with the commercial microbial chitinases. The same system was also used with native polyacrylamide gel electrophoresis at pH 8.9. Several bands were detected with the microbial chitinases. The same enzymes were also subjected to denaturing polyacrylamide gel electrophoresis in gradient gels containing 0.01% (W/V) glycol chitin. After electrophoresis, enzymes were renatured in buffered 1% (V/V) purified Triton X-100. Lytic zones were revealed by uv after staining with Calcofluor white M2R as for native gels. The molecular weights of chitinolytic enzymes could thus be directly estimated. In denaturing gels, as low as 10 ng of purified hen egg white lysozyme could be detected after 2 h incubation at 37 degrees C. Estimated molecular weights of St. griseus and Se. marcescens were between 24,000 and 72,000 and between 40,500 and 73,000, respectively. Some microbial chitinases were only resistant to denaturation with sodium dodecyl sulfate while others were resistant to sodium dodecyl sulfate and beta-mercaptoethanol.

Immunocytochemical localization of a wheat germ lysozyme in wheat embryo and coleoptile cells and cytochemical study of its interaction with the cell wall

Among several wheat (Triticum aestivum L.) germ proteins able to lyse Micrococcus lysodeikticus, one lysozyme (W1A) was purified by ion-exchange chromatography, gel filtration, and preparative polyacrylamide gel electrophoresis. Polyclonal antibodies against this lysozyme were raised in rabbits. The in situ localization of W1A lysozyme was achieved by the indirect protein A-gold technique. Large amounts of W1A lysozyme were found in cell walls whereas intercellular spaces, cytoplasm, and organelles were nearly free of labeling. Specificity of labeling was assessed with several controls. In an attempt to detect the presence of binding sites, W1A lysozyme was complexed to colloidal gold. Particles were specifically distributed in large amounts over wheat embryo and coleoptile cell walls. The absence of labeling over isolated coleoptile cell walls treated with 0.1 and 0.4 molar potassium hydroxide for hemicellulose extraction indicated that W1A lysozyme binding sites were probably of hemicellulosic nature.

A new lectin-gold complex for ultrastructural localization of galacturonic acids

We report the development of a cytochemical affinity technique for detection of galacturonic acids at the ultrastructural level. The highly purified gonad lectin from Aplysia depilans (AGL) was tagged with colloidal gold particles and used for labeling carbohydrates in resin-embedded sections of various plant and fungal tissues. Patterns of AGL binding sites were compared to those obtained with a D-galactose-specific lectin, Ricinus communis agglutinin I. Differences in labeling patterns were noted, indicating that the lectins exhibited differential carbohydrate binding. In addition, the considerable loss of labeling over isolated wheat coleoptile walls treated for removal of pectin, after incubation with the AGL-gold complex, strongly suggested an affinity of AGL for pectic substances. A series of cytochemical controls, including sugar inhibition tests, has proven the specificity of the technique and the high affinity of AGL towards galacturonic acids. The potential value of this new lectin for ultrastructural studies on cell wall pectic substances in plant biology and pathology is demonstrated.

Peripheral neurological complications of aortoiliac vascular disease

Six patients with an aortoiliac vascular disease and a peripheral neurological deficit are presented. Clinical and electromyographic findings revealed lumbosacral plexus, sciatic and femoral nerve lesions. A correlation is made between the level of the vascular lesion (aortic, aortoiliac or distally) and the type of peripheral nerve deficit observed. In a patient complaining of pain, weakness, or numbness in a leg, the differential diagnosis should include aortoiliac vascular disease. The peripheral neurological symptoms may be the initial manifestation of the vascular disease or may appear in the early post-operative period.

Misleading "pulmonary wedge pressure" after pneumonectomy: its importance in postoperative fluid therapy

Patients who have undergone pneumonectomy are reported to be at increased risk of serious pulmonary edema. Monitoring fluid therapy using the Swan-Ganz balloon-tipped catheter is therefore important in the perioperative management of these patients. Pulmonary artery occlusion pressure (PAOP), determined by inflating a balloon to occlude a branch of the pulmonary artery, is routinely used to measure pulmonary wedge pressure (PWP). In turn, PWP reflects left atrial pressure (LAP). We clinically observed postpneumonectomy patients in whom pulmonary edema developed, but whose PAOP was near normal. Our findings led us to suspect that PAOP in such patients may reflect a falsely low PWP value. We hypothesized that after pneumonectomy inflation of the balloon on the Swan-Ganz catheter to obtain PWP can result in considerable occlusion of the remaining cross-sectional area of pulmonary circulation. This occlusion acutely increases the right ventricular afterload, resulting in reduced cardiac output and reduced LAP. Although the PAOP under these circumstances still accurately reflects the LAP, these values have been artificially lowered; hence, they result in falsely low PWP readings. To verify this hypothesis, the following canine experiments were performed. Five dogs were monitored with a Swan-Ganz catheter, a left atrial catheter, and an electromagnetic flow probe applied to a carotid artery. Before pneumonectomy, inflation of the balloon to obtain PAOP caused no statistically significant change in LAP or carotid flow, and PAOP was identical to both LAP and PWP. (PWP was determined by advancing and wedging the pulmonary artery catheter tip into a peripheral branch without inflating the balloon.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hypertrophy of the gastrocnemius muscles: possible etiology of the popliteal artery entrapment syndrome?]

Excessive hypertrophy of the both heads of gastrocnemius has been reported as a possible etiology of a popliteal artery entrapment syndrome. However, this syndrome is rather unusual among all those young adults and athletes with hypertrophied gastrocnemius. An other factor must exist in addition of hypertrophy. We describe a patient presenting a more cranial migration of the both heads of gastrocnemius with a shorter and more proximal tendinous attachment above the femoral epicondyles. Thus, excessive hypertrophy of the both heads of gastrocnemius may be in fact the cause of a popliteal artery entrapment syndrome when there is a congenital abnormality of muscular migration.

Why remove an infected aortofemoral graft?

The radical treatment of infected vascular grafts is a major procedure with a high mortality and loss of limb. The authors review their experience with 13 consecutive cases of infected aortofemoral grafts treated conservatively during an 11-year period. The treatment consisted of wide incision and drainage of the infected area followed by assiduous irrigation with an antiseptic or antibiotic solution. In 10 patients the inguinal wound healed and the prosthesis was reincorporated; 8 of the 10 had a patent prosthesis and the treatment was considered successful, while 2 needed further surgery. Three patients died of hemorrhage or sepsis. Follow-up ranged from 8 to 144 months (mean 77 months). Two patients had a false aneurysm 3 and 7 years after wound healing. The results compare favourably with those of radical treatment. The authors believe a conservative approach must always be tried as the first step in the management of infected vascular prostheses. The gratifying results observed in their series, in both the short and long term, support this conservative approach, which is a satisfying alternative to radical operations with their high mortality and morbidity.

Celiac compression syndrome

The authors present their experience at the Hôpital St-Luc in Montreal with seven patients who had celiac compression syndrome. All underwent section of the median arcuate ligament to free the celiac axis and resection of the connecting nerve fibers of the solar plexus (periarterial neurectomy). At a mean follow-up of 36 months all patients were asymptomatic. In some cases, extrinsic compression of the celiac axis by the arcuate ligament can explain upper abdominal plain. An epigastric bruit in the presence of a normal digestive tract is an indication for lateral aortography to detect extrinsic compression. The pain in this syndrome cannot be explained solely on hemodynamic grounds; surgical treatment should include release of the celiac axis and complete periarterial neurectomy.

Dysphagia lusoria: anterior approach for definitive treatment

An aberrant right subclavian artery causing symptoms is rare in adults. Several surgical approaches have been advocated. On the basis of results obtained in two patients, the authors recommended an anterior approach, either a transternal bilateral thoracotomy or a median sternotomy, that affords excellent exposure for flush ligation and division of the right subclavian artery at the aorta, and reconstruction on the ascending aorta.

Angiography: an essential diagnostic aid in asymptomatic aortic aneurysm?

Aortography is a highly desirable diagnostic procedure for evaluating clinically diagnosed abdominal aortic aneurysm. In a retrospective study of 83 patients with such aneurysms, routine angiographic investigation changed the course of management in 17. The morbidity associated with angiography in the investigation of abdominal aortic aneurysm has been minimal. In this situation angiography provides more information than ultrasonography and therefore should be used routinely.

Cholesterol sulfate. II. Studies on its metabolism and possible function in canine blood

Previous in vitro studies to evaluate the possible role of cholesterol sulfate in the stabilization of the human erythrocyte membrane have been extended to the dog in vivo. Thus, following the injection of labelled cholesterol sulfate, a large fraction of the administered sterol conjugate is taken up by the membrane of the canine erythrocyte. Peak membrane levels were obtained within 30-60 min. Measurement of radioactivity associated with the plasma and red cell fractions in serial samples allowed the calculation of the half-life of cholesterol sulfate in each fraction. From the data obtained from the plasma of four dogs, the half-life was calculated to 5.8 plus or minus 0.9 h. The half-life of chlesterol sulfate associated with the erythrocyte membrane was calculated to be 6.7 plus or minus 1.2 h. In addition, following the intravenous administration of 0.2-0.7 mg of cholesterol sulfate/kg of body weight and withdrawal of serial blood samples, a significant diminution in the degree of hemolysis was observed when the red cells were exposed to hypotonic saline solutions. Maximal stabilization effects were observed at approx. 6-7 h after the administration of the sterol conjugate. Hemolytic properties returned to normal at approx. 24 h following the injection.