A Rhizobium selenitireducens protein showing selenite reductase activity

Biobarriers remove, via precipitation, the metalloid selenite (SeO₃⁻²) from groundwater; a process that involves the biological reduction of soluble SeO₃⁻² to insoluble elemental red selenium (Se⁰). The enzymes associated with this reduction process are poorly understood. In Rhizobium selenitireducens at least two enzymes are potentially involved; one, a nitrite reductase reduces SeO₃⁻² to Se⁰ but another protein may also be involved which is investigated in this study. Proteins from R. selenitireducens cells were precipitated with ammonium sulfate and run on native electrophoresis gels. When these gels were incubated with NADH and SeO₃⁻² a band of precipitated Se⁰ developed signifying the presence of a SeO₃⁻² reducing protein. Bands were cut from the gel and analyzed for peptides via LCMSMS. The amino acid sequences associated with the bands indicated the presence of an NADH:flavin oxidoreductase that resembles YP_001326930 from Sinorhizobium medicae. The protein is part of a protein family termed old-yellow-enzymes (OYE) that contain a flavin binding domain. OYE enzymes are often involved in protecting cells from oxidative stress and, due in part to an active site that has a highly accessible binding pocket, are generally active on a wide range of substrates. This report is the first of an OYE enzyme being involved in SeO₃⁻² reduction.

Rhizobium selenireducens sp. nov.: a selenite-reducing alpha-Proteobacteria isolated from a bioreactor

A Gram-negative, nonpigmented bacterium designated strain B1 was isolated from a laboratory bioreactor that reduced selenate to elemental red selenium (Se(0)). 16S rRNA gene-sequence alignment identified the isolate as a Rhizobium sp. belonging to the Rhizobium clade, which includes R. daejeonense, R. giardinii, R. undicola, R. larrymoorei, R. radiobacter, R. rubi, and R. vitis. R. radiobacter and R. rubi are its closest relatives as indicated by 16S rRNA gene-sequence alignments, which differ from strain B1 by 2.6% and 2.8%, respectively. Within this group, strains that show variances > 0.8% to 2.2% have been classified as different species. The major cellular fatty acids present in the B1 strain were C16:0 (1.8%), C18:0 (3.38%), 18:0 3-OH (1.6%), 18:1 omega7c (86.8%), 19:0 cycloomega8c (1.5%), and summed features 2 (3.8%) and 3 (1.2%). The large amount of 18:1 omega7c present is constant with members of this group of bacteria, but the small amounts of 16:0, 19:0 cycloomega8c, and summed feature 3 shows variance from R. radiobacter and R. rubi. The strain's phenotypic and biochemical characteristics are consistent with its placement in this genus.

A comparison of stent-induced stenosis in coronary and peripheral arteries

BACKGROUND AND OBJECTIVES

Restenosis is a complication of interventional procedures such as angioplasty and stenting, often limiting the success of these procedures. Knowledge regarding the relative behaviour of different arteries after these procedures is limited, despite the extensive use of different vascular models. Although the results from studies using different vessels are analysed to predict the behaviour of coronary arteries and other vasculature, direct controlled comparisons between different arteries are necessary for a better understanding of the differential response to restenosis.

METHODS

This study examines the response to stenting in coronary and internal iliac arteries as characterised by intimal hyperplasia and restenosis. In a swine model of in-stent stenosis, coronary arteries exhibited higher levels of intimal hyperplasia and per cent stenosis than internal iliac arteries.

RESULTS

After normalisation for injury score, coronary arteries were found to undergo 47% more intimal hyperplasia (p<0.05), whereas per cent stenosis normalised for injury score tended to be higher (p = 0.01). Other measurements reflecting post-stenting intimal hyperplasia (maximal intimal thickness, medial area) did not exhibit significant differences between the artery groups.

CONCLUSIONS

These results show that coronary vessels are more prone to develop significant intimal hyperplasia and subsequent restenosis than internal iliac vessels. A better insight into how different arteries and arterial components behave is important in understanding and developing newer and better therapeutic measures for restenosis.

Accumulation of nitrite in denitrifying barriers when phosphate is limiting

Permeable in situ denitrifying barriers can remove nitrate from groundwater. Barriers may be constructed by filling an excavated area with a porous mixture of sand, fine gravel, and substrate or by the injection of a nonaqueous phase substrate into an aquifer. The substrate stimulates the development of a denitrifying microbial community by providing an electron donor. The objective of this study was to determine the ability of denitrifying barriers to function under low-phosphate conditions. Sand columns injected with a soybean oil emulsion were used as laboratory models of denitrifying barriers. When a natural groundwater containing 17 mg l(-1) nitrate-N and 0.009 mg l(-1) phosphate-P was pumped through the columns, only a small amount of nitrate was removed from the water and, in some effluent fractions, 52% to 88% of the influent nitrate had converted to nitrite. Nitrite also accumulated when the phosphate concentration of the groundwater was increased to 0.040 or 0.080 mg l(-1) phosphate-P. Only when a 0.160 mg l(-1) phosphate-P supplement was added to the groundwater was there a loss of nitrate without a large accumulation of nitrite. The addition of solid calcium phosphate or rock phosphate to the sand columns was found to provide adequate phosphate for denitrification in short-term studies. These studies point out the need to ensure that adequate phosphate is present in denitrifying barriers especially when such barriers are used beneath phosphate-binding soils.

Use of vegetable oil in a pilot-scale denitrifying barrier

Nitrate in drinking water is a hazard to both humans and animals. Contaminated water can cause methemoglobinemia and may pose a cancer risk. Permeable barriers containing innocuous oils, which stimulate denitrification, can remove nitrate from flowing groundwater. For this study, a sand tank (1.1 x 2.0 x 0.085 m in size) containing sand was used as a one-dimensional open-top scale model of an aquifer. A meter-long area near the center of the tank contained sand coated with soybean oil. This region served as a permeable denitrifying barrier. Water containing 20 mg l(-1) nitrate-N was pumped through the barrier at a high flow rate, 1112 l week(-1), for 30 weeks. During the 30-week study, the barrier removed 39% of the total nitrate-N present in the water. The barrier was most efficient during the first 10 weeks of the study when almost all of the nitrate and nitrogen was removed. Efficiency declined with time so that by week 30 almost no nitrate was removed by the system. Nitrite levels in the effluent water remained low throughout the study. Barriers could be used to protect groundwater from nitrate contamination or for the in situ treatment of contaminated water. At the low flow rates that exist in most aquifers, such barriers should be effective at removing nitrate from groundwater for a much longer period of time.

Morphologic and temporal analysis of vascular smooth muscle cell apoptosis induced by c-myc and E1A

Apoptosis is a physiologic form of cell death present in many disease conditions. When the balance of mitosis versus apoptosis is altered, tumor-like growth or degeneration of tissues may ensue. This appears to occur in several diseases, including those of the cardiovascular system, where apoptosis plays a key role in atherosclerosis and restenosis following angioplasty. Since c-myc is upregulated in the pathogenesis of these diseases, we chose to study the sequential morphologic features of programmed cell death in vascular smooth muscle cells induced by c-myc and by the adenovirus early gene E1A. Morphology and timed events in apoptotic cell cultures were analyzed by scanning electron microscopy, transmission electron microscopy, and time-lapse videomicroscopy. We observed that both c-myc- and E1A-induced apoptosis (in serum-free medium) resulted in numerous, tightly packed clusters of apoptotic blebs, as well as in one or two asymmetrically larger blebs. Transmission electron miscroscopy analysis revealed the larger blebs contained mostly nuclear chromatin, whereas the many smaller fragments often had little or no chromatin. Time-lapse studies showed that apoptosis was induced at a slower rate in cells stably transfected with c-myc versus those stably transfected with E1A. The early changes of apoptosis, including cell shrinkage and intense blebbing, occurred in under 5 min in both cells. Slight alterations such as cell size and further rounding occurred up to 8 h following the initial changes of apoptosis. Rather than being a part of the apoptotic response, release from the culture floor almost entirely resulted from movement of the culture flask. These studies provide a framework of timed morphologic events for future mechanistic investigation into the key aspects of myc- and E1A-induced apoptosis in vascular smooth muscle.

Chlamydia pneumoniae and occlusive vascular disease: identification and characterization

Chlamydia pneumoniae, a respiratory pathogen, has been associated with occlusive vascular disease, including atherosclerosis and intimal hyperplasia, through seroepidemiologic studies. Furthermore, using immunohistochemistry (IHC), polymerase chain reaction (PCR), transmission electron microscopy (TEM), and in situ hybridization, this association has been reconfirmed by detecting this organism in atherosclerotic vascular tissue. This review summarizes and critically analyzes these findings and also discusses various mechanisms of how Chlamydia pneumoniae could be involved in the pathogenesis of occlusive vascular disease. Although more studies are needed to reproduce these results and, possibly, uncover a mechanism, the current literature fails to include detailed methodologies for studying Chlamydia pneumoniae. Therefore, to provide a general standard, we have also outlined specific protocols for IHC, PCR, and TEM. These protocols incorporate essential components from various studies and are presented in a concise and easily adaptable format.

Morphological and biochemical characterization and analysis of apoptosis

Apoptosis is a form of programmed cell death serving physiologic and homeostatic functions. However, recent evidence implicating apoptosis in the etiology and pathophysiology of known human diseases, such as heart diseases, cancer, AIDS, and neurodegenerative and autoimmune diseases are continually surfacing. This has spawned the need for identifying which methods are the most effective and well accepted to decipher its presence in a variety of research settings. We have therefore detailed the morphology and biochemical features of apoptotic cell death, with an emphasis on discriminating it from necrosis. In addition, we describe specific and selective techniques which are optimal to target hallmark apoptotic features, such as microscopy, Annexin V labeling, in situ nick-end labeling (TUNEL), and DNA fragmentation analysis by gel electrophoresis and ELISA for oligonucleosome-sized DNA. The advantages and disadvantages of each technique are discussed, as well as their experimental importance relative to one another. The methods have been described in a stepwise fashion, and can readily be applied in the majority of cell systems. Whether working on the tissue or single cell level, these methods are highly effective in qualifying and quantifying apoptosis. The application of these methods in conjunction with molecular techniques can further delineate the underlying mechanisms of apoptosis.

Functional and morphological evaluation of canine veins following preservation in different storage media

Injuries of endothelial and smooth muscle cells of autologous vein due to preservation in standard storage media may be responsible for graft failure. The effects of vein preservation with University of Wisconsin solution (UWs) on endothelial and smooth muscle cell function and morphology were compared to the effects of preservation with autologous whole blood (AWB) and normal saline (NS), which are frequently used in cardiovascular surgery. Canine external jugular and common femoral vein segments were preserved in the different solutions at 4 degrees C for 45 min and 24 hr. Rings (4-5 mm in length) from control and preserved veins were evaluated by isometric tension studies at 37 degrees C and by scanning and transmission electron microscopy. Differences between groups were evaluated by Student's t test or Mann-Whitney U test and by analysis of the variance, and considered to be significant at P < 0.05. Sensitivities to norepinephrine (NE) showed that a 45-min vein storage in AWB (5.7 +/- 0.2 mumol/L) but not in NS (5.8 +/- 0.2 mumol/L) or UWs (6.5 +/- 0.2 mumol/L) had a deleterious effect on function of smooth muscle (P < 0.05) when compared to control veins (6.6 +/- 0.2 mumol/L). Maximum contractile responses and sensitivities to NE were significantly altered (P < 0.05) after 24-hr vein storage in AWB (0.09 +/- 0.02 g/mm2 and 5.4 +/- 0.07 mumol/L) and NS (0.12 +/- 0.03 g/mm2 and 5.6 +/- 0.08 mumol/L) but not in UWs (0.36 +/- 0.06 g/mm2 and 6.4 +/- 0.07 mumol/L). With both storage times, acetylcholine-induced endothelium-dependent maximum relaxations and sensitivities were significantly reduced (P < 0.05) in veins stored in AWB and NS, but not in UWs, compared with controls. Similarly, transmission electron microscopy revealed marked neutrophil migration beneath the intimal surface of vessels and extensive separation and desquamation of endothelial cells with exposure of subendothelial structures in veins stored in AWB and NS. The results suggest that UWs is a suitable storage medium when compared to AWB and NS.

The sequence of a symbiotically essential Bradyrhizobium japonicum operon consisting of trpD, trpC and a moaC-like gene

The 2767 bp BamHI-HindIII fragment specifying the trpDC genes of B. japonicum I-110 was sequenced. The trpD and trpC genes each have three highly conserved 'Crawford' consensus sequences and are part of an operon with three open reading frames (ORFs). The third ORF has a predicted product with 58% amino-acid sequence identity with the gene product of E. coli moaC, a gene encoding an enzyme involved in biosynthesis of the molybdenum cofactor required for the activity of nitrate reductase and other Mo cofactor-requiring enzymes.

Short-term preservation of autogenous vein grafts: effectiveness of University of Wisconsin solution

BACKGROUND

Suboptimal preservation of autologous veins in storage solutions causes endothelial cell damage that can contribute to graft failure. The purpose of this study was to compare the effects of short-term storage of veins in autologous whole blood (AWB), 0.9% normal saline solution (NS), and University of Wisconsin solution (UWs) on vein structure and function after grafting.

METHODS

Autogenous jugular and femoral veins were atraumatically harvested from mongrel dogs. One vein segment was immediately implanted to serve as a control, and the other segments were stored for 45 minutes in AWB, NS, or UWs. The veins were implanted as reversed interposition graft in the carotid or femoral arteries. After 6 weeks light and scanning electron microscopy and isometric tension studies were performed on explanted vein grafts.

RESULTS

Morphologic studies revealed an intact endothelium that stained positively for factor VIII. Intimal thickness was similar between controls (48 +/- 12 microns) and veins stored in UWs (53 +/- 8 microns) (p = not significant), but it was significantly increased in veins stored in AWB (151 +/- 29 microns) and NS (149 +/- 18 microns) (p < 0.05). Sensitivity and maximum contraction to norepinephrine were not altered in veins preserved in UWs (6.0 +/- 0.1 mumol/L and 0.19 +/- 0.02 gm/mm2) but were significantly reduced (p < 0.05) in those stored in AWB (7.2 +/- 0.1 mumol/L and 0.08 +/- 0.02 gm/mm2) and NS (7.0 +/- 0.3 mumol/L and 0.09 +/- 0.02 gm/mm2) compared with controls (5.9 +/- 0.2 mumol/L and 0.20 +/- 0.02 gm/mm2). The sensitivity and maximum relaxation to acetylcholine and sodium nitroprusside of veins preserved in AWB, NS, and UWs were similar to controls (p = not significant).

CONCLUSIONS

Vein storage in UWs preserves smooth muscle cell function compared with veins stored in NS or AWB. Therefore UWs is a more suitable medium for short-term preservation of veins in cardiovascular operation.

Collagen COL4A3 knockout: a mouse model for autosomal Alport syndrome

A mouse model for the autosomal form of Alport syndrome was produced. These mice develop a progressive glomerulonephritis with microhematuria and proteinuria, consistent with the human disease. End-stage renal disease develops at approximately 14 weeks of age. TEM analysis of the glomerular basement membranes (GBM) during development of renal pathology revealed focal multilaminated thickening and thinning beginning in the external capillary loops at 4 weeks and spreading throughout the GBM by 8 weeks. By 14 weeks, half of the glomeruli were fibrotic with collapsed capillaries. Immunofluorescence analysis of the GBM showed the absence of type IV collagen alpha-3, alpha-4, and alpha-5 chains and a persistence of alpha-1 and alpha-2 chains (these chains normally localize to the mesangial matrix). Northern blot analysis using probes specific for the collagen chains illustrate the absence of COL4A3 in the knockout, whereas mRNAs for the remaining chains are unchanged. An accumulation of fibronectin, heparan sulfate proteoglycan, laminin-1, and entactin was observed in the GBM of the affected animals. The temporal and spatial pattern of accumulation was consistent with that for thickening of the GBM as observed by TEM. Thus, expression of these basement membrane-associated proteins may be involved in the progression of Alport renal disease pathogenesis. The levels of mRNAs encoding the basement membrane-associated proteins at 7 weeks were unchanged.

A noninjury, diet-induced swine model of atherosclerosis for cardiovascular-interventional research

To investigate whether atherosclerotic vascular disease in the microswine model can be induced by atherogenic diet alone and does not require balloon injury or endothelial denudation as widely stated in the literature, 28 female Yucatan microswine were fed a high-fat, high-cholesterol diet, including 2% sodium cholate, for an average of 310 +/- 13 days. Four control swine were placed on a regular diet for an average of 287.2 +/- 7.8 days. Selective coronary arteriography and morphologic and histologic studies were performed at the end of this period. Coronary arteries were fixed in vivo by pressure perfusion of formalin. Angiograms and sequential histologic sections were reviewed by a double-blind team. The angiography did not show apparent disease in all vessels but generally revealed mild irregularity. Quantitatively, there was a 30.5 +/- 3.5% stenosis (mean +/- standard error, P < 0.05 vs. control) in left anterior descending (LAD), 40.7 +/- 4.5% of stenosis in right coronary artery (RCA) (P < 0.01 vs. control), and 24.8 +/- 3.7% of stenosis in left circumflex artery (LCX). The lesions were eccentric in 95% of LCA, 95.8% of RCA, and 75% of LCX, and the remainder were concentric lesions. Typical lesions were characterized by significant intimal proliferation, cholesterol clefts, necrotic cores, heavy extracellular fat deposition, and calcification. Control animals had only occasional, minimal intimal lipid deposition in coronary arteries. These findings suggest that the Yucatan microswine is an ideal coronary atherosclerosis animal model for vascular research. Lesions can be induced by atherogenic diet alone. Cholesterol uptake is increased by adding sodium cholate to the feed. Moreover, balloon injury of the intima or media is not required to induce significant atherosclerotic lesions in coronary arteries.

Malpractice protection: communication of diagnostic uncertainty

Malpractice claims against pathologists for misdiagnosis have been sharply rising, especially in the areas of breast fine-needle aspirations (BFNAs) and cervical (Pap) smears. The current state of medical malpractice law is reviewed as it relates to pathologists' anatomic reports. Communication is one of the best medical malpractice prevention tools. This article examines anatomic pathology reports in terms of the merits of communicating diagnostic error rates to the clinician/patient. In the areas of BFNAs and cervical smears, dissemination of diagnostic error rates in the cytology report is recommended. This would help safeguard against malpractice liability being imposed without showing a deviation by the cytopathologist from reasonable practice standards.

Fresh vein allograft survival in dogs after cyclosporine treatment

Synthetic grafts are widely used for peripheral arterial reconstructions when autologous veins are not available, but their results have not been satisfactory. Venous allograft may be used as an alternative to synthetic prostheses. The aim of the study was to explore the immunosuppressive efficacy of Cyclosporine A (CyA) as a means of preventing venous allograft failures and rejection. We utilized 56 mongrel dogs. Immunological incompatibility was checked with the skin graft method. Donor inferior vena cava was transplanted into the infrarenal abdominal aorta of recipient animals. One group (group 1, 10 dogs) served as a control and three groups received CyA treatment regimens. Group 2 (10 dogs) received postoperative oral CyA treatment for 30 days. Group 3 (12 dogs) received a vein graft pretreated with a CyA solution without postoperative immunosuppressive therapy. Group 4 (9 dogs) received a vein graft pretreated with a CyA solution and postoperative CyA treatment for 30 days. Allografts were examined at 30 days for patency, aneurysmal dilatation, gross structural changes, inflammatory response, and lymphocytic infiltration. Sex chromatine assessment determined the origin (donor or recipient) of the endothelial cells. The allografts from groups 1 and 3 showed significant aneurysmal dilatation and perivenous inflammation when compared to dogs treated with oral CyA therapy (P < 0.0002). Moreover allografts treated with CyA therapy had a better-developed venous neointima (P < 0.009) with less fibrin (P < 0.02) and thinner medial (P < 0.0009) with less fibrin (P < 0.02), and thinner medial (P < 0.0009) and adventitial layers (P < 0.02). No significant differences were observed in neointimal thickness among the four groups. Lymphocytic infiltration was greater in the group of animals who did not receive oral CyA therapy (P < 0.0004). Barr bodies status showed significant differences between oral CyA treated groups and nontreated groups (P < 0.0003). Oral CyA therapy reduced aneurysmal dilatation and immunological response, promoted the development of a neoendothelium, and preserved the structure of the venous layers. Graft pretreatment with CyA flushing did not have a significant immunosuppressive effect.

University of Wisconsin solution effects on intimal proliferation in canine autogenous vein grafts

This study was carried out to investigate if the University of Wisconsin solution (UWs) is suitable for long-term preservation of autogenous vein grafts (AVG) prior to transplantation, compared to autologous whole blood (AWB) and normal saline (NS). Autogenous jugular and femoral veins were harvested from adult mongrel dogs, using a "no-touch" technique. One segment of vein was immediately implanted to serve as a control, while other segments were stored for 24 hr at 4 degrees C in AWB, NS, or UWs. The control and the preserved veins were implanted as reversed interposition grafts in the common carotid or femoral artery positions. After 6 weeks, scanning electron microscopy revealed an intact endothelial cell monolayer in all vein grafts that was stained positively for factor VIII. The degree of intimal thickening, as assessed by light microscopy in the middle position of the grafts, was similar in controls (52.0 +/- 15.8 microns) and in veins stored in UWs (58.5 +/- 16.1 microns), but it was significantly increased (P < 0.05) in veins preserved in NS (198.9 +/- 19.5 microns) and in AWB (312.0 +/- 171.6 microns). Isometric tension studies revealed that maximum contraction and sensitivities (assessed by EC50) to norepinephrine were significantly reduced (P < 0.05) in AVG stored in AWB (0.05 +/- 0.02 g/mm2 and 5.5 +/- 2.8 microM), but not in UWs (0.16 +/- 0.03 g/mm2 0.92 +/- 0.34 microM) and NS (0.09 +/- 0.03 g/mm2 and 3.0 +/- 1.1 microM), compared with controls (0.17 +/- 0.03 g/mm2 and 0.99 +/- 0.38 microM). Acetylcholine (Ach)-induced maximum relaxations were similar in all of the veins.(ABSTRACT TRUNCATED AT 250 WORDS)

A laparoscopic intraperitoneal onlay mesh technique for the repair of an indirect inguinal hernia

OBJECTIVE

This study was done (1) to determine whether congenital indirect inguinal hernias in male pigs could be repaired by placing a polypropylene mesh prosthesis over the defect intra-abdominally, (2) to measure the incidence of adhesions between intra-abdominal viscera and the prosthesis with and without the adhesion barrier oxidized regenerated cellulose, (3) to determine the incidence of other complications, and (4) to assess the effect on fertility.

SUMMARY BACKGROUND DATA

Several techniques for laparoscopic inguinal herniorrhaphy are currently being evaluated to determine whether there are advantages over conventional inguinal herniorrhaphy. Perhaps the most controversial is the intraperitoneal onlay mesh procedure (IPOM). Its advantage is its simplicity (in that the repair is accomplished by placing a prosthesis over the hernia defect intra-abdominally, avoiding a groin dissection). Its disadvantage is the potential for complications because the prosthesis is in contact with the intra-abdominal viscera.

METHODS

In male pigs, polypropylene mesh alone or polypropylene mesh plus the adhesion barrier oxidized regenerated cellulose (composite prosthesis) was fixed to the peritoneum surrounding the hernia defect. In phase 1 (6-week follow-up), two groups of 13 pigs each underwent herniorrhaphy at laparotomy or laparoscopy. In phase 2 (7.1-month follow-up), 21 pigs underwent laparoscopic herniorrhaphy.

RESULTS

All IPOM herniorrhaphies were successful. The prostheses adhered most frequently to the bladder, followed by small bowel, peritoneum, and cord structures. Prosthetic erosion into these organs was not observed. Laparoscopically placed prostheses in phases 1 and 2 had significantly less surface covered by adhesions (13% +/- 13% and 19% +/- 27%, respectively) and a lower adhesion tenacity grade (1.5 +/- 0.9 and 1.3 +/- 1.1, respectively) than those placed at laparotomy (44% +/- 27% and 2.5 +/- 0.7, respectively; p < 0.01). In phase 1, a histologic evaluation of laparoscopically placed specimens demonstrated significantly thinner above-mesh fibrotic tissue compared with the prostheses implanted at laparotomy (p < 0.04). In either phase, the use of the adhesion barrier did not produce any histologic difference between the polypropylene alone and the composite prosthesis. Fertility studies were performed in phase 2 and showed no adverse effects caused by either prosthesis.

CONCLUSIONS

This study demonstrated that the intraperitoneal placement of a polypropylene prosthesis was an effective technique for indirect inguinal herniorrhaphy in a pig. Furthermore, with laparotomy, the addition of oxidized regenerated cellulose significantly decreased the rate of adhesion formation to the prosthesis. However, oxidized regenerated cellulose would appear to have no value when used with a prosthesis placed laparoscopically.

Functional and morphological assessment of rat aorta stored in University of Wisconsin and Eurocollins solutions

University of Wisconsin (UW) and Eurocollins (EC) solutions are widely used for preservation of organs before transplantation. However, effect of storage solutions on vascular interface for transplant success is not known. In this study, we have used rat aorta as a model and assessed the effects of cold storage in UW and EC solutions on smooth muscle and endothelial function and the morphology. Smooth muscle and endothelial functions of the rat aorta were assessed using in vitro isometric tension measurement. Morphologic studies were done with scanning and transmission electron microscopy. No significant difference in contractile response to either norepinephrine (NE) or potassium chloride was observed between control aorta and aorta stored in UW solution for 1 hr or 24 hr. In contrast, sensitivity, but not the reactivity to NE and KCl, was increased in aorta stored in EC solution for 1 hr. If the tissues were stored in EC solution for 24 hr, both sensitivity and reactivity to NE and KCl were significantly reduced. Relaxatory response to acetylcholine, in endothelium-intact vessels were reduced in aortas stored in EC solution, but not in UW solution. The magnitude of relaxations observed in tissues stored in the EC solution for 24 hr was less than in tissues stored for 1 hr. Sodium nitroprusside elicited similar relaxatory response in endothelium-denuded control tissue and in tissues stored in UW and EC solution. Electron microscopy data revealed marked swelling of the cell, loss of mitochondria and other intracellular organelles, and striking calcium deposits after preservation of the vessels in EC for 1 or 24 hr. In aorta stored in UW solution for 24 hr, endothelial and smooth muscle cells were intact, with moderate-size vacuoles in the cytoplasm. These results suggest that the UW solution is more suitable than EC solution for short-term preoperative storage of blood vessels.

Imipenem-induced seizure: a case of inappropriate, excessive, and prolonged surgical prophylaxis

Imipenem-cilastatin is a broad spectrum antibiotic that is generally used for antibiotic-resistant hospital-acquired infections. Imipenem has been reported to cause CNS toxicity including seizures in 1.5-10% of patients. The authors present a case in which imipenem, inappropriately utilized for surgical prophylaxis in excessive doses (1 gram every six hours) and for a prolonged period of time (24 days), induced a tonic-clonic generalized seizure in a patient with no history of seizure activity. The identification of this ADR lead to a number of clinical and administrative actions within our institution. Drug-induced seizures have occurred and will continue to occur as healthcare professionals exceed recommended dosing guidelines to treat critically ill patients. As pharmacists, it is extremely important to use therapeutic drug monitoring and pharmaceutical care principles to assist physicians in individualizing drug regimens for our patients to prevent these ADRs from occurring, thereby significantly effecting patients' outcomes.

Ethylene Production by Root Nodules and Effect of Ethylene on Nodulation in Glycine max

Nodulated soybean roots produced more ethylene and contained more 1-aminocyclopropane-1-carboxylic acid than uninoculated roots. Nodules produced more ethylene and contained more 1-aminocyclopropane-1-carboxylic acid per gram of material than roots. Almost all of the ethylene produced by the nodules was produced by the plant fractions of the nodules. Ethylene, at physiological concentrations, did not inhibit nodulation in soybeans.

Mortality of professional chemists in England and Wales, 1965-1989

Several studies on the mortality of chemists have revealed a lower overall mortality but an excess of deaths from certain diseases, in particular, cancers. This study determined the causes of mortality of 4,012 chemists among 14,884 members of The Royal Society of Chemistry who were followed for a period of 25 years. The results demonstrated consistency with other studies. There was an overall low mortality rate, with fewer deaths than expected from cancers, but an excess mortality from lymphatic and hematopoietic cancers, in particular leukemias. There was an excess of deaths from certain gastrointestinal cancers. There was reduced mortality from respiratory diseases, including lung cancers, and from cardiovascular disease. New findings reported in this study are increased mortality from cancers of the duodenum and kidney, certain skin cancers, mental disorders, and diseases of the nervous system.

Healing of high-porosity polytetrafluoroethylene arterial grafts is influenced by the nature of the surrounding tissue

The aim of this study was to determine the influence of the nature of the perigraft tissue in the healing pattern of high-porosity polytetrafluoroethylene (PTFE) vascular grafts. Nine-centimeter long segments of unreinforced experimental high-porosity (60 microns) PTFE grafts were placed as abdominal aortic interposition in mongrel dogs. Three grafts served as controls (group A); in five dogs (group B) a 25 x 25 cm piece of devascularized omentum was wrapped around the graft. In five dogs (group C) the omentum with its own vascular supply was completely wrapped around the graft. Animals were killed 4 weeks after surgery. The percentage of thrombus-free area was 31% in group A grafts, 39% in group B grafts, and 79% in group C grafts (p less than 0.01). Scanning electron microscopy showed many confluent areas of endothelium-like cells in the midportion of group C grafts, corresponding to capillary ingrowth. Transmural endothelial migration was more evident in group C grafts. We conclude that the nature of the perigraft tissue influences transmural capillary migration and the endothelialization rate of high-porosity PTFE grafts in dogs. Agents able to increase capillary formation in the perigraft tissue might improve endothelialization of vascular grafts.

Importance of ulceration of carotid plaque in determining symptoms of cerebral ischemia

In order to investigate the relationship between carotid plaque morphology and symptoms of cerebral ischemia, a prospective clinicopathological study was performed. Ninety consecutive intact carotid plaques obtained from surgery and 43 carotid plaques from cadavers without symptoms of cerebral ischemia were evaluated. Ulceration and mural thrombus were the only morphologic findings statistically correlated to the presence of hemispheric symptoms (p less than 0.02). Intramural hemorrhage was more common in patients with hemispheric symptoms but this difference was not statistically significant (p = 0.31). Plaque causing high degree stenosis had a higher incidence of intramural hemorrhage (p = 0.04) and ulceration (p less than 0.02). Ulceration of plaque plays a major role in the onset of hemispheric symptoms. The results of our study support the hypothesis that in the majority of the cases, hemispheric symptoms are embolic in nature.

Comparison of two techniques to isolate microvascular endothelial cells from the omentum

The purpose of the study was to compare two different techniques for isolation of omental microvascular endothelial cells (ECs). Segments of unreinforced polytetrafluorethylene (PTFE) grafts, 9 cm long and 6 mm in diameter, were implanted in 22 dogs as an aortic interposition. Fourteen grafts were seeded with a mean of 7 x 10(5) viable ECs, derived from the microvessels of the omentum: eight grafts (group A) were seeded with ECs obtained by collagenase digestion and by filtration through a pore mesh; six grafts (group B) were seeded with ECs obtained by collagenase digestion and by Percoll gradient separation. In eight grafts (group C), the ECs were not added to the preclot mixture and served as a control. Animals were sacrificed 5 weeks after surgery. The percentage of thrombus-free area was 65 +/- 22% for group A grafts and 74 +/- 15% for group B grafts (NS). The subendothelial layer was 280 +/- 60 microns thick in group A and 220 +/- 30 microns thick in group B (P less than 0.05). Seeded grafts showed a higher production of 6-keto-PGF1 alpha after addition of sodium arachidonate than control grafts. Percoll gradient separation allows isolation of a more purified suspension of ECs. Refinements in omental EC procurement are still required to minimize contamination with other types of cells.

Inflammatory aneurysms of the abdominal aorta: incidence, pathologic, and etiologic considerations

Among 486 patients undergoing repair for abdominal aortic aneurysm (AAA) during a 12-year period, 30 (6.2%) had evidence of "inflammatory" AAA. One patient (3%) had acute rupture, and six patients (20%) had chronic contained rupture. Ureteral obstruction was evident in 20% of the patients. In the early period of the study there were two postoperative deaths and operative time and blood loss were significantly increased. In the last period of the study, no attempt was made to separate the duodenum and the ureters from the aneurysm; there was no operative mortality, and operative time and blood loss were similar to that of patients with atherosclerotic aneurysms. In 23 of 100 specimens of atherosclerotic AAA, microscopic findings resembling inflammatory AAA were found. On the basis of our study we conclude the following: (1) Inflammatory AAAs are simply atherosclerotic aneurysms that show an unusual accentuation of the chronic inflammation observed in relation to atherosclerotic aneurysms. (2) Operative technique should be modified to avoid excessive dissection and lysis of ureters and duodenum. (3) Excellent early and late results can be expected with proper surgical technique. (4) The causes of AAA are multiple, and chronic contained rupture of the aneurysm and reactive lymphatic hyperplasia might play a role of greater significance than previously thought.

Natural history of recurrent carotid artery disease

Controversy exists as to whether early and late recurrent stenosis of the carotid artery represents two distinct types of recurrence or whether it is the same type of lesion detected at different times. Eleven specimens from patients whose carotid arteries were reoperated upon were examined. A temporal sequence was noted: with increasing intervals, the relative presence of areas of myointimal hyperplasia tended to decrease, whereas the relative presence of features of atherosclerosis tended to increase. The clinical data and B-mode ultrasound studies performed from one to 190 months after 210 carotid endarterectomies were reviewed. Twenty-seven carotid arteries (12.9 per cent) exhibited hemodynamically significant restenosis. Three ultrasonographic patterns were described: homogenous soft plaque, homogenous hard plaque and heterogenous plaque. A previous correlation between ultrasonographic and pathologic findings showed the three ultrasound patterns to correlate with myointimal hyperplasia, fibrous atherosclerotic plaque and complex atherosclerotic plaque, respectively. Soft plaques were detected earlier than heterogenous plaques (p less than 0.001). Results from serial studies showed progression of soft plaque to hard or heterogenous plaque, or both. Early and late recurrent lesions are the same type of lesion detected at different intervals. Symptoms of cerebral ischemia are more common at the stage of heterogenous plaque (p = 0.02).

Ultrasonographic features of carotid plaque and the risk of subsequent neurologic deficits

In a prospective study, 214 consecutive patients considered not to be candidates for surgical intervention were evaluated by means of duplex scanning. Of the patients, 135 had no symptoms and 79 had a history of previous neurologic symptoms. In 139 sides duplex scanning demonstrated nonhemodynamic stenosis (lumen diameter reduction, less than 50%) and in 99 sides, hemodynamic stenosis (lumen diameter reduction, 50% or greater). Of the 238 carotid artery plaques examined, 167 were homogenous and 71 were heterogenous. During a mean follow-up of 34 months, 27 new focal neurologic deficits occurred. Patients with previous symptoms had a higher incidence of new deficits (18/79 vs 9/135) (p less than 0.01). The severity of the stenosis and the presence of a heterogenous plaque were statistically correlated with the occurrence of new deficits (p less than 0.001). Multivariate analysis showed that the ultrasonographic pattern and the severity of the stenosis were independent variables. We conclude that a heterogenous plaque should be considered an unstable plaque with the possibility of causing cerebral ischemia.

Congenital abdominal aortic aneurysms in the young. Case report and review of the literature

Aneurysms of the aorta are rare in children and young adults. We report a case of a 19-year-old man with a saccular abdominal aortic aneurysm (AAA). No associated disorders were discovered in this patient. The aneurysm was resected and a Dacron aortic graft was implanted. Nine years after operation the patient was in good health without evidence of other aneurysms. Thirty-two cases of probable congenital abdominal aortic aneurysms were collected from the literature. In 19 cases, the cause of aneurysm was not ascertained. We identified two groups of patients with probably congenital AAAs: type I congenital AAA, in which there is a generalized disorder of the arterial tissue and usually aneurysms are present in other areas and type II congenital AAA, in which there is a localized defect of the abdominal aorta, without aneurysms in other areas. We speculate that a congenital defect localized to the wall of the abdominal aorta was the cause of the aneurysm in this patient (type II congenital AAA).

Seeding with endothelial cells derived from the microvessels of the omentum and from the jugular vein: a comparative study

Segments of an experimental polytetrafluoroethylene graft (9 cm long, 6 mm I.D.) of high porosity were implanted in 25 dogs as aortic interposition grafts. Nine grafts were seeded with a mean of 7 x 10(5) viable endothelial cells (ECs) derived from the jugular vein (group A) and eight were seeded with a mean of 7 x 10(5) viable ECs derived from the microvessels of the omentum (group B). Eight grafts were not seeded and they served as controls (group C). Animals were put to death 5 weeks after graft implantation. The thrombus-free area was measured at 81% +/- 10% in group A, 65% +/- 22% in group B, and 25% +/- 13% in group C (p less than 0.05, group A vs group B; p less than 0.05, group B vs group C). The thickness of the subendothelial layer was 151 +/- 60 microns in group A, 280 +/- 60 microns in group B, and 100 +/- 75 microns in group C (p less than 0.001, group B vs groups A and C). The production of 6-keto-PGF1 alpha in the presence of sodium arachidonate was higher in seeded grafts (p less than 0.05). Omentally derived microvessel ECs can be seeded in vascular grafts; refinements in the technique of EC procurement are required to minimize contamination and to obtain ECs with more effective biologic activity.

Priority setting for health surveys of workers

In determining the priorities for health surveys of workers, several factors need to be assessed, including (a) existing legislation, (b) the identification of an agent as hazardous and (c) the potential value of the surveys. Each of these factors has been examined in more detail with a view to determining the various elements that need to be taken into account in establishing priorities. In addition, a review has been made of occupational health services and of occupational health monitoring in the European Community.

Influence of 5-Methyltryptophan-Resistant Bradyrhizobium japonicum on Soybean Root Nodule Indole-3-Acetic Acid Content

Bradyrhizobium japonicum mutants resistant to 5-methyltryptophan were isolated. Some of these mutants were found to accumulate indole-3-acetic acid (IAA) and tryptophan in culture. In greenhouse studies, nodules from control plants inoculated with wild-type bradyrhizobia contained 0.04, 0.10, and 0.58 μg of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules −1 , respectively. Nodules from plants inoculated with 5-methyltryptophan-resistant bradyrhizobia contained 0.94, 1.30, and 10.6 μg of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules −1 , respectively. This manyfold increase in nodule IAA content indicates that the Bradyrhizobium inoculum can have a considerable influence on the endogenous IAA level of the nodule. Further, these data imply that much of the IAA that accumulated in the high-IAA-containing nodules was of bacterial rather than plant origin. These high-IAA-producing 5-methyltryptophan-resistant bacteria were poor symbiotic nitrogen fixers. Plants inoculated with these bacteria had a lower nodule mass and fixed less nitrogen per gram of nodule than did plants inoculated with wild-type bacteria.

Studies of a human mesothelioma

Abdominal fluid from a patient with mesothelioma was cultured in vitro, and a cell line designated JMN was established. This cell line has undergone more than 100 passages. Electron microscopic, karyotypic, and heterotransplantation studies as well as the capability of collagen synthesis by this cell line indicated that it is of malignant mesothelial origin. The cell line has proved very useful for the isolation of human pathogenic viruses.

Biohydrogenation of unsaturated fatty acids. Purification and properties of cis-9,trans-11-octadecadienoate reductase

The enzyme catalyzing the second step in the biohydrogenation pathway of linoleic acid by Butyrivibrio fibrosolvens cis-9,trans-11-octadecadienoate reductase has been purified to near homogeneity. It has a molecular weight of 60,000 and appears to be a single subunit. The purified enzyme contains 2 mol of iron, 10 mol of fucose, and 12 mol of galactose per 60,000 g. The iron, but not the carbohydrate, is required for enzymatic activity. Phosphatidylethanolamine was also found to be associated with the purified enzyme. Unlike the cell extract that can reduce the double bond of the fatty acid with NADH or alpha-tocopherolquinol as a reductant, the purified enzyme can utilize only alpha-tocopherolquinol. This indicates that another component of the reduction system exists that couples the production of alpha-tocopherolquinol to the oxidation of NADH.

Intercomparison study on the determination of single administration toxicity in rats

In 1977, the Commission of the European Communities initiated an intercomparison study to determine the single administration oral LD50 value in rats of each of 5 chemicals with the aims of comparing experimentation technologies, determining the degree of variation in the results and the various parameters used to establish the LD50 value, and establishing a common protocol for the determination of the LD50 value. Sixty-five laboratories in 8 countries took part in the first study. The significant variation in protocol may have led to the large interlaboratory variation observed in the results. Therefore, participating laboratories carried out a second study using a common protocol, preceded by a pilot study. A total of 100 laboratories in 13 countries participated. A majority of results of the second study are currently being analyzed, and the indications are that the interlaboratory variation has been significantly reduced.

Biohydrogenation of unsaturated fatty acids. Hydrogenation by cell-free preparations of Butyrivibrio fibrisolvens

Hydrogenation of cis-9,trans-11-octadecadienoic acid to yield trans-11-octadecenoic acid by cell-free preparations of Butyrivibrio fibrisolvens has been obtained under strictly anaerobic conditions. Reduced methyl viologen, NADH, and an endogenous electron donor each can serve as a reductant. Inhibition studies and gel filtration patterns reveal the presence of at least two hydrogenation systems, one of which is coupled through a flavin, possibly FMN. Although the enzymes comprising the biohydrogenation pathway, the fatty acid reductases and linoleic acid isomerase, are part of the bacterial membrane, they do not appear to be constituted as a multienzyme complex.

Role of pectic and cellulolytic enzymes in the invasion of the soybean by Rhizobium japonicum

Past workers have suggested pectic enzyme involvement in the invasion of legumes by Rhizobium. However, no role for pectic acid, pectin, or methyl cellulose depolymerase enzymes in the invasion of R. japonicum was suggested by the current study. Seedling inoculation with infective bacteria did not result in increased enzyme activity. Rhizobium japonicum cell-free culture extracts and 3-indoleacetic acid did not affect the activation, induction, or binding of these enzymes.

Simple method for culturing anaerobes

A simple, effective method is needed for growing obligate anaerobes in the clinical laboratory. This report describes a pre-reduced anaerobic bottle that can be taken to the bedside for direct inoculation, provides a flat agar surface for evaluation of number and morphology of colonies, and can be incubated in conventional bacteriological incubators. Each anaerobic culture set consisted of two bottles containing brain heart infusion agar and CO(2). Gentamicin sulfate (50 mug/ml) was added to one of these to inhibit facultative enteric bacilli. Comparison of the anaerobic bottles with an identical aerobic bottle which was also routinely inoculated permitted early identification of anaerobic colonies. Representative species of most anaerobic genera of proven pathogenicity for man have been isolated from this system during 10 months of routine use.