Hydrolysis of benzonitrile herbicides by soil actinobacteria and metabolite toxicity.

The soil actinobacteria Rhodococcus rhodochrous PA-34, Rhodococcus sp. NDB 1165 and Nocardia globerula NHB-2 grown in the presence of isobutyronitrile exhibited nitrilase activities towards benzonitrile (approx. 1.1-1.9 U mg(-1) dry cell weight). The resting cell suspensions eliminated benzonitrile and the benzonitrile analogues chloroxynil (3,5-dichloro-4-hydroxybenzonitrile), bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) and ioxynil (3,5-diiodo-4-hydroxybenzonitrile) (0.5 mM each) from reaction mixtures at 30 degrees C and pH 8.0. The products were isolated and identified as the corresponding substituted benzoic acids. The reaction rates decreased in the order benzonitrile >> chloroxynil > bromoxynil > ioxynil in all strains. Depending on the strain, 92-100, 70-90 and 30-51% of chloroxynil, bromoxynil and ioxynil, respectively, was hydrolyzed after 5 h. After a 20-h incubation, almost full conversion of chloroxynil and bromoxynil was observed in all strains, while only about 60% of the added ioxynil was converted into carboxylic acid. The product of ioxynil was not metabolized any further, and those of the other two herbicides very slowly. None of the nitrilase-producing strains hydrolyzed dichlobenil (2,6-dichlorobenzonitrile). 3,5-Dibromo-4-hydroxybenzoic acid exhibited less inhibitory effect than bromoxynil both on luminescent bacteria and germinating seeds of Lactuca sativa. 3,5-Diiodo-4-hydroxybenzoic acid only exhibited lower toxicity than ioxynil in the latter test.

Recurrent inguinal hernia: preferred operative approach.

Inguinal herniorrhaphy remains one of the most common general surgical operations, with approximately 10 to 20 per cent performed for recurrence. Subsequent repairs provide considerable technical challenge, as well as substantially greater risk of developing further recurrence. Mesh repair is advocated by several specialized hernia centers, demonstrating re-recurrence rates less than 2 per cent. Detractors of this repair include cost, technical difficulty, and risk for infection. The purpose of this study was to compare results of mesh and nonmesh repairs for recurrent inguinal hernia, either using an anterior or posterior approach, at a large teaching institution. From January 1, 1985, to December 31, 1994, 146 patients underwent repair for recurrent inguinal hernia at the Veterans Administration Hospital at Memphis, Tennessee. Patients were stratified by type of repair: Lichtenstein (Mesh), open anterior (OA), Bassini, Marcy, McVay, Shouldice, and preperitoneal with or without mesh. Patient ages and weights were similar between groups. Mean operative time for Mesh repair (104 +/- 4 minutes) was longer than that for OA repairs (80 +/- 5 minutes, P < 0.05) or preperitoneal without mesh repairs (92 +/- 5 minutes, P < 0.05). Mesh-based posterior repairs had the longest operative times (116 +/- 5 minutes). Hospital stay averaged 2.8 +/- 0.3 days, similar among all groups. One wound infection (1.0%) occurred in patients undergoing Mesh repair, which required operative drainage. No patient required removal of mesh. Two patients in the Mesh group (5.9%) developed recurrence compared with four recurrences (18.0%) in patients undergoing OA repairs. Only one patient with a mesh-based posterior repair recurred (1.9%) compared to eight without mesh (21.6%, P < 0.01). Follow-up ranged from 2 to 12 years. Repair of recurrent inguinal hernia using either an anterior or posterior mesh repair technique, performed at a teaching facility, provides superior recurrence rates without increasing risk for infection or length of stay. Preperitoneal mesh based repair is the preferred technique.

Glycyl-L-glutamine-enriched total parenteral nutrition maintains small intestine gut-associated lymphoid tissue and upper respiratory tract immunity.

BACKGROUND: i.v. administration of a total parenteral nutrition (TPN) solution results in small intestinal gut-associated lymphoid tissue (GALT) atrophy, lowers small intestinal immunoglobulin A (IgA) levels, and impairs upper respiratory tract secretory IgA-mediated mucosal immunity; isonitrogenous supplementation of TPN with 2% glutamine attenuates these changes. This experiment examines whether a 2% glycyl-L-glutamine-enriched TPN solution reverses i.v. TPN-induced changes as effectively as L-glutamine. METHODS: Male Institute of Cancer Research (ICR) mice underwent intranasal inoculation with H1N1 influenza virus to establish immunity. After 3 weeks, mice were randomized to chow, i.v. feeding of a TPN solution, glutamine-enriched TPN, or glycyl-L-glutamine-enriched TPN. After 4 days of feeding, mice were challenged intranasally with influenza virus and killed at 40 hours to determine viral shedding from the respiratory tract; normal convalescent mice do not shed virus because they possess intact IgA-mediated mechanisms Lymphocytes were isolated from Peyer's patches, the intraepithelial layer, and lamina propria to determine cell yields. RESULTS: Total lymphocyte yield in the Peyer's patches, the intraepithelial layer, and lamina propria decreased with TPN but remained normal with glutamine and glycyl-L-glutamine. Upon challenge, 70% of the mice in the TPN group shed virus in nasal secretions, whereas only 20% of the glutamine-treated group, 18% of glycyl-L-glutamine group and none of the Chow group were virus positive. CONCLUSIONS: L-Glutamine and glycyl-L-glutamine have similar effects on i.v. administered TPN-associated (GALT) atrophy and decreased upper respiratory tract immunity.

Mesh inguinal herniorrhaphy: a ten-year review.

Inguinal herniorrhaphy remains one of the most common surgical operations, with approximately 10 to 20 per cent performed for recurrence. Reviews by specialized hernia centers show mesh repair has a recurrence rate of 0.2 per cent. Detractors of this repair include increased cost, technical difficulty, and risk for infection. The purpose of this study was to compare mesh versus nonmesh inguinal herniorrhaphy at a large teaching institution. From 1985 to 1994, 892 patients underwent primary repair for inguinal hernia at the Veterans Administration Hospital at Memphis, TN. Patients were stratified by repair [Lichtenstein (Mesh), open anterior (Bassini, Marcy, McVay, and Shouldice), laparoscopic (Lap), and preperitoneal (Post)]. Operative time for Mesh repair (111 +/- 2 minutes) was longer than for Bassini or McVay (91 +/- 2 and 98 +/- 2 minutes; P < 0.05), and Lap repairs were longer than all others (192 +/- 16 minutes; P < 0.05). Hospital stay averaged 2.2 +/- 0.1 days for Mesh versus 2.6 +/- 0.1 days for all repairs combined (P = not significant). Mesh patients developed four wound infections (1.0%), none requiring mesh removal, versus nine infections (1.8%) in other groups (P = not significant). One Mesh patient (0.3%) developed recurrence, compared with 16 (3.5%) with open anterior repair (P < 0.01). Inguinal herniorrhaphy using an open mesh repair technique provides superior recurrence rates without increasing risk for infection, length of stay, or technical difficulty.

Recovery of gut-associated lymphoid tissue and upper respiratory tract immunity after parenteral nutrition.

OBJECTIVE: The authors characterize the recovery of parenteral nutrition-induced changes in gut-associated lymphoid tissue (GALT) and upper respiratory tract immunity with enteral nutrition and provide further information defining the effects of enteral feeding on mucosal immunity. SUMMARY BACKGROUND DATA: The small intestine plays a prominent role in development and maintenance of mucosal immunity, both intestinal and extraintestinal, primarily through immunoglobulin A (IgA)-mediated mechanisms. Prior research has shown that mice fed total parenteral nutrition (TPN) have reduced GALT T and B cells, the cells responsible for IgA production, as well as impaired upper respiratory tract immunity to viral challenge of previously immunized animals. The recovery of TPN-induced changes in GALT and upper respiratory tract immunity after enteral refeeding is studied. METHODS: Male institute of Cancer Research mice received 5 days of TPN followed by 0 to 4 days of chow. Small intestinal GALT was characterized by flow cytometry. In a second experiment, animals were immunized intranasally with moused-adapted influenza virus. Three weeks later, one group received a 5-day course of TPN followed by enteral refeeding for 5 days. A second group received TPN alone. Both groups were challenged with intranasal virus and killed 40 hours postchallenge to determine viral shedding from the upper respiratory tract. RESULTS: Animals fed TPN only had significantly fewer GALT lymphocytes compared with those chow-fed control subjects. Peyer's patch counts increased after a single day of refeeding, returning to normal levels by 48 hours. Lamina propria counts remained significantly depressed after 24 hours of refeeding, but also returned to normal after 48 hours of refeeding. The T-cell and B-cell populations mimicked total cell patterns. Lamina propria CD4+/CD8+ ratio returned to normal only after 72 hours of refeeding. None of the 9 animals refed enterally for 5 days were positive for viral shedding, compared with 8 of 12 matched TPN-fed animals. CONCLUSIONS: Enteral refeeding after TPN is associated with rapid repletion of GALT cellularity, initially within Peyer's patches and subsequently within the lamina propria. Refeeding corrects the impairment of IgA-mediated upper respiratory tract antiviral immunity occurring with TPN administration. This work further enhances the authors' knowledge of the underlying immunologic differences influenced by routes of nutrition.

Effect of glutamine-enriched total parenteral nutrition on small intestinal gut-associated lymphoid tissue and upper respiratory tract immunity.

BACKGROUND: Our prior work shows that total parenteral nutrition (TPN) causes small intestinal gut-associated lymphoid tissue (GALT) atrophy, lowers small intestinal immunoglobulin A (IgA) levels, and impairs secretory IgA-mediated mucosal immunity of the upper respiratory tract. These experiments examine whether an isonitrogenous 2% glutamine-enriched TPN solution prevents these changes. METHODS: Institute of Cancer Research mice were randomized to chow (chow), intravenous feeding of a TPN solution (TPN), or glutamine-enriched TPN (glutamine) groups. After mice were fed for 5 days, lymphocytes were isolated from Peyer's patches, the intraepithelial layer, and lamina propria to determine cell yields and phenotypes. Total small intestinal IgA levels were analyzed by means of enzyme-linked immunosorbent assay. In a second series of experiments, mice underwent intranasal inoculation with H1N1 virus to establish immunity. After 3 weeks mice were randomized to chow, TPN, or glutamine groups. After feeding for 5 days, mice were rechallenged with intranasal virus and killed at 40 hours to determine viral shedding from the upper respiratory tract. RESULTS: Total lymphocyte yield in the Peyer's patches, the intraepithelial layer, and lamina propria, small intestinal IgA levels, and the CD4+/CD8+ ratio in the lamina propria decreased with TPN but remained normal with glutamine. On rechallenge, 87% of the mice in the TPN group shed virus in nasal secretions, whereas only 38% of the glutamine-treated group (p < 0.05 versus TPN) and 7.1% of the chow group (p < 0.002 versus TPN) were virus positive. CONCLUSIONS: Isonitrogenous supplementation of TPN with 2% glutamine improves IgA-mediated protection in the upper respiratory tract and normalizes GALT populations.

Effect of bombesin on impairment of upper respiratory tract immunity induced by total parenteral nutrition.

OBJECTIVE: To determine the effect of the neuropeptide bombesin on total parenteral nutrition-induced impairment of upper respiratory tract immunity. DESIGN: Randomized, controlled trial. PARTICIPANTS: Thirty-six adult male Institute for Cancer Research mice weighing 25 to 35 g. INTERVENTIONS: Mice were inoculated intranasally with H1N1 virus. At 3 weeks, mice were randomized to receive chow plus intravenous saline (n = 12), intravenous total parenteral nutrition (n = 12), or intravenous total parenteral nutrition plus bombesin (n = 12) administered 3 times daily at 15 micrograms/kg. After 5 days, mice were rechallenged with intranasal virus and killed at 40 hours to determine viral shedding from the respiratory tract; normal convalescent mice do not shed virus because of intact IgA-mediated mechanisms. MAIN OUTCOME MEASURES: Viral shedding was determined by collection of nasal secretions. Samples were diluted and incubated with a suspension of Madin-Darby canine kidney cells. Viral growth was determined by hemagglutination. RESULTS: Body weight was similar between the total parenteral nutrition and bombesin groups; however, both were significantly lower than that in the chow group (P < .05). After 6 days of feeding, no mice in the chow group shed virus, compared with 6 (50%) of the mice in the total parenteral nutrition group. Of the mice in the bombesin group, only 1 was positive for viral shedding. The total parenteral nutrition group showed increased viral shedding compared with both the chow group (P < .01) and the bombesin group (P < .05). CONCLUSIONS: Exogenous administration of bombesin reversed the total parenteral nutrition-associated impairment of upper respiratory tract immunity to an IgA-mediated infectious challenge. These observations support the concept of a common mucosal immune system, since neuropeptides are endogenous to the gastrointestinal and respiratory tracts. Hormonal modulation of immunity is a promising avenue of treatment for patients who require total parenteral nutrition.

A comparison of laparoscopic and traditional open splenectomy in childhood.

This study aimed to determine whether laparoscopic splenectomy is more advantageous than open splenectomy in pediatric patients. Data from 61 patients treated between June 1983 and September 1994 were reviewed. Length of hospitalization, hospital costs, operating time, and postoperative complications were evaluated. Forty-seven patients had open splenectomy. Nineteen of these underwent concomitant procedures. Fourteen patients had laparoscopic splenectomy, and four had concomitant cholecystectomy. The data show a trend toward a 1-day reduction in hospital stay associated with laparoscopic splenectomy (P < .02). Operating time was 83% longer for the laparoscopic approach (P < .001), and operating costs were almost $3,000 more (P < .001) than for open splenectomy. The total hospital cost also was greater for laparoscopic procedures (P < .1), primarily reflective of a more than $3,000 difference for splenectomy alone (P < .02). Two of the fourteen laparoscopic patients (14%) had complications. One patient with Evan's syndrome had pneumonia that required antibiotics. Another patient required conversion to an open procedure because of poorly controlled hemorrhage from a short gastric vessel. Twelve of the open splenectomy patients (25%) had complications: atelectasis (3), fever (4), wound infection (2), pneumonia (1), laryngospasm (1), and pancreatitis (1). The authors conclude that laparoscopic splenectomy is a safe but currently more expensive alternative to open splenectomy, primarily because of the use of disposable instruments. Benefits include a shorter hospital stay, no greater risk of postoperative complications, and subjective improvement in the cosmetic result. Disadvantages include increased operating time and cost. Evaluation of larger series will be needed to determine the significance of the difference in complication rates between the two procedures.

Rectus femoris flap repair of recalcitrant inguinal lymphoceles after heart transplantation.

For access to cardiopulmonary bypass in orthotopic heart transplantation, cannulation of the femoral artery is reserved for situations in which aortic cannulation cannot be performed safely. Femoral cannulation, however, is associated with multiple complications including lymphatic leakage manifested as either lymphocutaneous fistula or lymphocele. Although lymphatic leakage can often be treated conservatively, the length of time required for resolution, the delayed healing, and the risk of secondary infection makes more rapid and sure treatment essential for the immunocompromised and steroid-dependent heart transplant recipient. The purpose of this article is to describe a technique with the use of a rectus femoris muscle flap for operative treatment of inguinal lymphocele in transplant recipients refractory to both standard conservative and operative management and demonstrate its applicability in three cases. The use of a rectus femoris flap provides elimination of dead space, increased vascularity to eliminate infection and enhance wound healing, and, potentially, a conduit for lymphatic drainage.