Bilateral popliteal artery injury from bumper crush injury

Blunt trauma to the knee of sufficient force to result in knee dislocation or fracture is commonly associated with popliteal artery injury. The challenging problem of bilateral popliteal artery injury has been rarely reported. We describe a case of bilateral popliteal artery injury after bumper crush injury between two automobiles that illustrates a successful method of management. Expeditious revascularization with minimum ischemia time was obtained by using the posterior approach, rather than the conventional medial approach, allowing two surgical teams to work simultaneously.

Susceptibility of corneal and conjunctival pathogens to ciprofloxacin

Ciprofloxacin 0.3% ophthalmic solution has been shown to be effective in the treatment of bacterial keratitis and conjunctivitis, and many physicians use ciprofloxacin as sole therapy in these conditions. In this retrospective study, we found seven of 84 isolates from corneal and conjunctival cultures that were resistant to ciprofloxacin. All of the resistant organisms were gram positive. Six of the isolates (Staphylococcus aureus, Staphylococcus hominis, and four isolates of the Streptococcus viridans group) were from corneal cultures, and one (Staphylococcus aureus) was from a conjunctival culture. Yearly records of systemic isolates from 1988 to 1993 (n = 35,308) demonstrated a statistically significant decrease in susceptibility for several organisms that are common pathogens in the conjunctiva and cornea: Pseudomonas aeruginosa (95-90%, p = 0.001); Staphylococcus aureus (96-87%, p < 0.0001); Staphylococcus spp., coagulase negative (97-81%, p < 0.0001); Enterococcus spp. (92-79%, p < 0.0001); Acinetobacter anitratus (97-77%, p = 0.0006); and Enterobacter cloacae (100-96%, p = 0.03). Although the susceptibility of corneal and conjunctival isolates in this series remained relatively high (91.7%), a much larger series of systemic isolates that are common ocular pathogens revealed a statistically significant increase in resistance to ciprofloxacin over the preceding 5 years.

Managing choledocholithiasis in the laparoscopic era

BACKGROUND

Management options for common bile duct stones have explained in the era of laparoscopic cholecystectomy (LC), and selecting the most appropriate method for each patient can be problematic due to the difficulty of predicting accurately which patients have choledocholithiasis (CDL). In order to improve selection of appropriate treatment for CDL, treatment options were analyzed for outcome retrospectively during a 25-month period beginning June 1, 1992.

PATIENTS AND METHODS

Four hundred four patients underwent LC; 48 (12%) had CDL identified at preoperative endoscopic retrograde cholangiopancreatography (ERCP) or intraoperative cholangiogram (IOCG). Forty-seven patients were referred for preoperative ERCP for suspected CDL, 23 (49%) of whom had proven duct stones and underwent endoscopic sphincterotomy and stone retrieval with an 87% success rate.

RESULTS

Of 357 patients scheduled for LC without preoperative ERCP, 236 had IOCG, of which 25 (11%) demonstrated CDL. Seven patients had open common bile duct exploration (CBDE). Sixteen patients had postoperative ERCP after positive IOCG, 7 (44%) of which were positive for CDL and whose stones were removed with 100% success. Two patients were observed, anticipating spontaneous passage of a small stone.

CONCLUSIONS

Preoperative ERCP should be applied selectively. For the large majority of patients without preoperative evidence of CDL, we recommend routine IOCG; if CDL is demonstrated, an intraoperative decision can be made to proceed to postoperative ERCP in the usual case or to open CBDE for very large or multiple stones. Observation in anticipation of spontaneous passage may be appropriate for small, solitary common duct stones. Continuing advances in laparoscopic CBDE are likely to reduce further the need to rely on ERCP in managing CDL.

Redistribution of blood flow after carotid endarterectomy

PURPOSE

We wanted to characterize the immediate effect of endarterectomy on flow of the arteries composing the extracranial carotid artery system.

METHODS

Transit time ultrasound probes were used to measure flow through the carotid bifurcation in 48 patients undergoing endarterectomy. Maximum single-diameter stenosis affecting the internal carotid artery (ICA) was determined by angiography. The significance of differences between means were determined by t tests and analysis of variance; linear and nonparametric correlation analyses were also applied to analyze the relation between stenosis and several flow-derived parameters.

RESULTS

Common carotid artery flow significantly increased (p = 0.0043) from a mean value of 264 +/- 99 ml/min to 314 +/- 98 ml/min, corresponding to an average percent increase of 34.3% +/- 71.3%. ICA flow increased from 128 +/- 69 ml/min to 173 +/- 66 ml/min (p < 0.0001), with an average percent increase of 74.9% +/- 114.9%. External carotid artery (ECA) flow decreased from 129 +/- 61 ml/min to 106 +/- 49 ml/min (p = 0.0098), representing an average percent decrease of -5.2% +/- 48.2%. The difference between ECA and ICA mean flow changes is highly significant (p < 0.001). The percent change in ECA flow did not correlate with preoperative stenosis. We noted, however, a positive correlation between stenosis and the ECA/ICA flow ratio before endarterectomy (Spearman r = 0.31, p = 0.032), indicating that more severe stenosis led to a greater distribution of blood into the ECA. The ECA/ICA flow ratio fell from an initial value (ECFbef/ICFbef) of 1.52 +/- 1.74 before endarterectomy to 0.69 +/- 0.37 (ECFaft/ICFaft) after endarterectomy (p = 0.0006).

CONCLUSIONS

The data are consistent, with the ECA being an important collateral path for cerebral perfusion when ICA stenosis exists. When endarterectomy relieves bifurcation stenosis, common carotid artery blood flow is redistributed preferentially to the ICA at the expense of ECA flow, consistent with a change in the relative resistances of the two vessels resulting from operative reconstruction.

Composite porosity of expanded polytetrafluoroethylene vascular prosthesis

Polytetrafluoroethylene (PTFE) prostheses were modified to produce two types of composite porosity PTFE grafts: type I--inner 60 microns/outer 20 microns and type II--inner 20 microns/outer 60 microns. These composite porosity PTFE designs were investigated for bleed through, graft healing and patency and compared with high porosity PTFE (60 microns) and standard PTFE (20 microns) grafts. The grafts were implanted into the carotid and femoral arteries of dogs and retrieved after 4, 12 and 18 weeks. Both composite porosity grafts showed significantly less bleed through than standard and high porosity grafts after reperfusion. In composite grafts, the 60-microns layer allowed fibrovascular tissue and histiocyte ingrowth from perigraft tissue, but the 20-microns layer did not. Neointima formation occurred earlier and endothelialization was more extensive in high porosity grafts, but seroma formation occurred in 25% of cases. In type I composite porosity grafts, smooth muscle cells of neointima migrated into the pores of the graft, providing a firmly anchored intima. Type II composite porosity grafts allowed better ingrowth of fibrovascular tissue at the outer layer from the perigraft tissue; however, endothelialization was not completed. Composite porosity grafts should be considered for evaluation in specific clinical situations.

Operative site bacteriology as an indicator of postoperative infectious complications in elective colorectal surgery

Toward the completion of elective colorectal operations, 75 patients had qualitative aerobic and anaerobic cultures of specimens obtained from peritoneal irrigation fluid, anastomoses sites, and abdominal wound irrigation fluid to determine if a correlation exists between intraoperative flora and postoperative infectious complications. Patients enrolled in this prospective study received a mechanical bowel prep and a 12-18 hour course of perioperative intravenous antibiotics. Comparisons were made between the 60 (80%) patients who had no postoperative infections and the 15 (20%) who developed postoperative infectious complications (9 wound infections, 6 intraabdominal infections). There were significantly more low anterior resections in patients who developed postoperative infection compared to those who had no postoperative infection (26% vs 2%), while there were more colocolostomies in the group with no infections (38% vs 7%). Streptococcus spp., Bacteroides fragilis group, and Escherichia coli were the most commonly isolated organisms from each of the three sites sampled. Isolation of > or = 3 organisms from incisional wound cultures (P = 0.017) and < or = 4 organisms from peritoneal irrigation (P = 0.009) or anastomotic culture (P = 0.004) correlated with development of postoperative infectious complications. Thus, patients with infectious complications had significantly more isolates than those without infectious complications, and were more likely to have had a low anterior resection. These data suggest that future clinical studies should reexamine the duration of perioperative antimicrobials based on early laboratory reports of qualitative and quantitative operative site bacteriology.

Meropenem versus tobramycin plus clindamycin for treatment of intraabdominal infections: results of a prospective, randomized, double-blind clinical trial

The efficacy of meropenem was compared to that of the combination of tobramycin plus clindamycin (T/C) in a multiinstitutional clinical trial of treatment for patients suffering intraabdominal infection. Among the 177 patients enrolled and randomized, 127 were clinically evaluable and 86 were microbiologically evaluable. Analysis of data on an intent-to-treat basis for all randomized patients and on the basis of a successful outcome (absence of any infection) for clinically evaluable patients failed to detect any difference in efficacy between the two treatments. Infection was cleared in 92% of meropenem- and 89% of T/C-treated clinically evaluable patients. Eradication of pathogens also was similar in the two treatment groups. Overall, adverse drug experiences were comparable between the two treatment groups, with the exception of an increase in serum creatinine level (which occurred more frequently in patients receiving T/C). Meropenem appears to be efficacious for the treatment of intraabdominal infections.

Effect of dopamine on renal blood flow and cardiac output

OBJECTIVE

To characterize the relationship between changes in renal blood flow and cardiac output induced by dopamine, hypothesizing that at low doses renal blood flow changes more than cardiac output.

DESIGN

Anesthetized swine had renal blood flow and cardiac output measured during either continuous dopamine infusions (2 to 8 micrograms/kg per minute) or bolus dosing (1 to 16 micrograms/kg), and increases in both were compared. Two different fluid protocols were compared using constant dopamine infusions. In the constant pulmonary capillary wedge pressure protocol, intravenous fluids were titrated to keep this parameter constant. In the other protocol, fluid therapy was held constant at 10 mL/kg per hour.

RESULTS

With infusions, mean increases in renal blood flow and cardiac output were relatively equal. The maximum increase was 35% at 8 micrograms/kg per minute under the constant pulmonary capillary wedge pressure protocol, with no significant differences (P > .1) found between the change in renal blood flow and cardiac output at any dose in either protocol. With bolus dosing, renal blood flow increased significantly more than cardiac output at 1, 4, and 8 micrograms/kg (P < .05).

CONCLUSION

Disproportionate increases in renal blood flow compared with cardiac output at low bolus doses show initial renal responses to be independent of cardiac output. The infusion data suggest that renal responses exhibit tachyphylaxis or that cardiac output slowly accommodates to decreased total peripheral resistance.

Enhanced neointima formation and attachment on the high-porosity inner surface of modified PTFE vascular grafts

Highly porous PTFE arterial prostheses form endothelium more extensively than the low-porosity grafts in clinical use, but are subject to seroma formation. PTFE vascular grafts were modified to produce a highly porous inner layer (inner layer 60 or 90 microns, outer layer 20 microns). The effect of this modified, composite design on the histology of graft healing was investigated. Twenty-five modified and 25 control grafts, each 4 mm in diameter by 5 cm in length, were implanted into carotid and femoral arteries of dogs. No late seroma formation was observed. After 12 and 18 weeks, the neointima of the grafts was examined by light microscopy and scanning electron microscopy. At 2- and 4-mm distances from the proximal and distal anastomoses, intimal thickness of the control grafts was 238.7 and 96.1 microns, respectively; for the modified grafts it was 236.2 and 202.8 microns at 18 weeks. Thus, the neotinima of modified grafts was thicker than that of control grafts when measured at 4 mm from the anastomoses. Neointimal coverage was less extensive in the control grafts than in modified grafts (26.8 +/- 6.1% vs. 58.8 +/- 13.2%; p < .05). Smooth muscle cells were seen on light-microscopy to penetrate the highly porous inner layer; on scanning electron microscopy, the PTFE fibrils appeared to anchor the neointima of the modified graft. The results suggest that modified PTFE grafts with an inner surface of 60 or 90 microns internodal distance have enhanced formation and anchoring of neointima while remaining impervious to blood.

AIDS and cancer registry linkage: measurement and enhancement of registry completeness. The National AIDS/Cancer Match Study Group

BACKGROUND AND METHODS

To measure AIDS registry completeness for Kaposi's sarcoma (KS) and cancer registry completeness for KS and non-Hodgkin's lymphoma (NHL), we linked AIDS and cancer registries at selected health departments.

RESULTS

We found 10,350 people with KS: 1,935 reported only to the AIDS registry, 1,428 reported only to the cancer registry, and 6,987 reported to both. Ninety-three cases of non-HIV-associated KS were expected. For KS, AIDS registry completeness was 84% [6,987/(6,987 + 1,428 - 93)] and cancer registry completeness was 78% [6,987/(6,987 + 1,935)]. Cancer registry completeness for AIDS-related NHL was 76%.

CONCLUSION

If this linking were conducted nationally, about 5,700 additional cases of AIDS and 10,000 additional cases of AIDS-related cancers would be recorded.

Clinical correlates of anaerobic bacteriology in peritonitis

Recent surgical reports indicate that for patients with secondary bacterial peritonitis, surgeons do not routinely use the identification of the bacterial pathogens and determination of their antimicrobial susceptibilities in choosing antimicrobial therapy. Further, some surgeons advocate abandoning the routine practice of obtaining culture specimens from patients with complicated appendicitis, because the data from the clinical laboratory have not been found to have an impact on postoperative care. We review the rationale for continued surveillance of and implementation of bacteriological data in treatment of secondary peritonitis. We also describe in detail the anaerobic flora of secondary peritonitis, the unique susceptibility patterns of these organisms, and the specific virulence factors of anaerobes, particularly Bacteroides fragilis. The fact that clinical investigations sometimes result in treatment failure when gram-negative anaerobes are resistant to the antimicrobials used or when complete antimicrobial susceptibility data are not available emphasizes the need for accurate and early knowledge of the bacteriologic characteristic of the flora of the operative site. We emphasize the relationship of in vitro susceptibility of intraoperative isolates with clinical outcome. We propose a cooperative trial that would demonstrate that successful antimicrobial therapy should be based on the susceptibility of the flora of the operative site, which correlates with clinical outcome.

Variability in measurement of abdominal aortic aneurysms. Abdominal Aortic Aneurysm Detection and Management Veterans Administration Cooperative Study Group

PURPOSE

The purpose of this study was to report interobserver and intraobserver variability of computed tomography (CT) measurements of abdominal aortic aneurysm (AAA) diameter and agreement between CT and ultrasonography observed in the course of a large, multicenter, randomized trial on the management of small AAAs.

METHODS

CT measurements of AAA diameter from participating centers were compared with measurements made from the same scan by a central laboratory. Blinded central remeasurement of a randomly selected subset of these CT scans was used to assess intraobserver variability. Agreement between AAA measurements by CT and ultrasonography done within 30 days of each other was also assessed.

RESULTS

For interobserver pairs of local and central CT measurements of AAA diameter (n = 806), the difference was 0.2 cm or less in 65% of pairs, but 17% differed by at least 0.5 cm. For intraobserver pairs of central CT remeasurements (n = 70), 90% differed by 0.2 cm or less, 70% were within 0.1 cm, and only one differed by 0.5 cm. Of 258 ultrasound-measured and central CT pairs, the difference was 0.2 cm or less in 44% and at least 0.5 cm in 33%. Ultrasound measurements were smaller than central CT measurements by an average of 0.27 cm (p < 0.0001). Local CT and ultrasound measurements showed a marked preference for recording by half centimeter.

CONCLUSIONS

A high degree of precision is possible in CT measurement of AAA diameter, but this precision may not be obtained in practice because of differences in measurement techniques. Differences between imaging modalities increase variability further. Variations in AAA measurement of 0.5 cm or more are not uncommon, and this should be taken into account in management decisions. Efforts to reduce variation in measurement are warranted and might include (1) seeking agreement between surgeons and radiologists on a precise definition of AAA diameter, (2) limiting the number of radiologists who measure AAAs, and (3) use of calipers and magnifying glass for CT measurements.

Clinical trials of extended spectrum penicillin/beta-lactamase inhibitors in the treatment of intra-abdominal infections. European and North American experience

The clinical results with the beta-lactam/beta-lactamase inhibitor class of antimicrobials in the treatment of intra-abdominal infections are reviewed. The three agents now in clinical use--ampicillin/sulbactam, ticarcillin/clavulanate, and piperacillin/tazobactam--are effective against a broad variety of gram-positive and gram-negative organisms. The beta-lactamase inhibitor is an irreversible inactivator of beta-lactamase enzymes, which are produced by many gram-negative and gram-positive organisms. Randomized, prospective, clinical trials of each agent indicate clinical cure rates > 85% that are not significantly different from those obtained with second-generation cephalosporin or aminoglycoside plus antianaerobic comparators, with the exception of one study. Piperacillin/tazobactam has also been compared with imipenem, with equivalent or superior outcomes, depending on the dose of the imipenem comparator. Side effects in the non-penicillin-allergic patient are few. The incidence of abnormal renal function tests are generally lower than that obtained with aminoglycoside plus antianaerobic therapy. Introduction of this new beta-lactam antimicrobial group provides another important strategy for the adjunctive management of surgically treated, community-acquired, intra-abdominal infection.

Control of lytic development in the Streptomyces temperate phage phi C31

The repressor gene, c, is required for maintenance of lysogeny in the Streptomyces phage phi C31. The c gene expresses three in-frame N-terminally different protein isoforms at least one of which is thought to bind to a 17bp highly conserved inverted repeat (CIR) sequence found at 18 (or more) loci throughout the phi C31 genome. Here we present evidence that one of these loci, CIR6, and its interaction with the products of the repressor gene are critical in the control of the lytic pathway in phi C31. To the right of CIR6, according to the standard map of phi C31, an 'immediate-early' promoter, ap1, was discovered after insertion of a fragment containing CIR6 upstream of a promoterless kanamycin-resistance gene, aphII, to form pCIA2. pCIA2 conferred kanamycin resistance upon Streptomyces coelicolor A3(2) but not upon a phi C31 lysogen of S. coelicolor. Operator-constitutive (Oc) mutants of pCIA2 were isolated and the mutations lay in CIR6, i.e. CIR6:G14T and CIR6:C2A. Primer extension analysis of RNA prepared from an induced, temperature-sensitive lysogen of S. coelicolor localized a mRNA 5' endpoint 21 bp to the right of CIR6. The importance of the ap1/CIR6 region in the regulation of lytic growth was demonstrated by the analysis of a virulent mutant, phi C31 vir1, capable of forming plaques on an S. coelicolor phi C31 lysogen. phi C31vir1 contained a DNA inversion with the breakpoints lying within the integrase gene (which lies approximately 7 kbp to the right of CIR6) and in the essential early region between CIR6 and the -10 sequence for ap1. The separation of ap1 from its operator was thought to be the basis for the virulent phenotype in phi C31 vir1. Band-shift assays and DNase I footprinting experiments using purified 42 kDa repressor isoform confirmed that CIRs 5 and 6 were indeed the targets for binding of this protein. The 42 kDa repressor bound to CIR6 with higher affinity than to CIR5 in spite of their identical core sequences. Repressor bound at CIR6 facilitated binding at CIR5. The high-affinity binding to CIR6 was abolished with the Oc mutant, CIR6:G14T. Hydroxyl radical footprinting and dimethyl sulphate methylation protection of the 42 kDa repressor-CIR6 interaction suggested that the protein bound in the major groove and to one face of the DNA.

Inguinal wound fluid collections after vascular surgery: management by early reoperation

Inguinal wounds complicated by significant fluid collections after vascular grafting procedures were managed by exploration soon after recognition in 14 patients. Within 24 hours, incisions were reexplored, fluid collections were evacuated and cultured, and closed suction drains were placed. The wound was reapproximated, and broad spectrum antibiotics were given intravenously until 24 hours after removal of the drain. Variables evaluated included spontaneous drainage before exploration, positive intraoperative wound cultures, exposure of graft when the wound was opened, and type of graft used. On careful follow-up, from 5 months to 3.5 years, averaging 14 months, only one patient had an infected graft, occurring 6 months after the wound exploration. There were no complications in wound healing from the inguinal explorations. These results suggest that early exploration and reclosure of clinically significant postoperative fluid collections is safe, results in primary healing, and has a low rate of subsequent graft infection.

Meropenem versus imipenem/cilastatin in the treatment of hospitalized patients with skin and soft tissue infections

Meropenem is a new carbapenem antibiotic shown to resist degradation by renal dehydropeptidase I. In a multicenter, open-label, prospective trial, we compared the efficacy and safety of meropenem with imipenem/cilastatin in patients with skin and soft tissue infections. Patients received either 500 mg of meropenem every 8 hours (n = 184) or 500 mg of imipenem/cilastatin every 6 hours (n = 193), by intravenous infusion for an average of 6 to 7 days. Satisfactory clinical responses were achieved in 120 (98%) of 123 assessable meropenem-treated patients and in 120 (95%) of 126 assessable imipenem/cilastatin-treated patients. Satisfactory bacteriologic responses were achieved in 120 (98%) of 123 assessable meropenem-treated patients and in 120 (95%) of 126 assessable imipenem/cilastatin-treated patients. Satisfactory bacteriologic response rates were high as well: 94% with meropenem and 91% with imipenem/cilastatin. Between-group differences in satisfactory response rates were not significant (95% confidence interval, -2.29 to 6.93 [clinical]; -2.73 to 10.39 [bacteriologic]). Overall pathogen eradication rates (for aerobes and anaerobes) were slightly higher for meropenem. Elevated liver enzymes were the most frequent adverse events in each treatment group. Meropenem was well tolerated and as effective as imipenem/cilastatin in treatment of hospitalized patients with skin and soft tissue infections.

A metal-dependent form of protein phosphatase 2A

Highly purified bovine heart protein phosphatase 2A catalytic subunit lost virtually all of its activity during storage at -70 degrees. When the enzyme was preincubated with Co2+, over 35% of the original activity was restored. Freshly prepared protein phosphatase 2A purified from bovine heart was stimulated at least 3 to 4-fold by pretreatment with Co2+ or Mn2+. Activation by Co2+ appeared to be irreversible whereas activation by Mn2+ was partially reversed after the cation was chelated with excess EDTA/EGTA. The sensitivity of Co2(+)-stimulated protein phosphatase 2A to okadaic acid or inhibitor-2 was similar to that of spontaneously active protein phosphatase 2A. The enzyme was converted to a latent form by treatment with phosphate or pyrophosphate. The latent form was completely reactivated by preincubation with Co2+. These results demonstrate that protein phosphatase 2A, like phosphatase 1, can exist in a metal ion-dependent form and may represent a new mechanism for the regulation of protein phosphatase 2A activity.

Interferon treatment of Mooren's ulcers associated with hepatitis C

PURPOSE/METHODS

The cause of Mooren's ulcer is unknown. We examined a patient with chronic hepatitis C who had a corneal ulceration that resembled Mooren's corneal ulcer.

RESULTS/CONCLUSION

The corneal ulceration progressed despite appropriate medical and surgical interventions. Recombinant interferon alpha 2b finally led to resolution of the process. The resolution correlated with normalization of the patient's liver function tests. Corneal ulcerations that resemble Mooren's ulcer may be associated with hepatitis C. Recombinant interferon alpha 2b seems to induce remission in the corneal as well as the systemic condition.

Concordance of human leukocyte antigen haplotype-sharing, CD4 decline and AIDS in hemophilic siblings. Multicenter Hemophilia Cohort and Hemophilia Growth and Development Studies

OBJECTIVE

To assess the association between human leukocyte antigen (HLA) haplotypes and the incidence rates of CD4 decline to < 20% and to AIDS.

DESIGN

Retrospective cohort study of 95 HIV-1-infected hemophilic sibling pairs.

METHODS

HLA haplotype-sharing between siblings was assigned on the basis of serologic typing of HLA class I alleles and molecular typing of HLA class II alleles. Concordance of time to CD4 decline to < 20% and to AIDS within and between sibling pairs was assessed by analysis of variance models and calculations of intraclass correlation coefficients. The age-adjusted relative risks of these two endpoints for unique class II haplotypes were determined from proportional hazards models.

RESULTS

Sibling pairs sharing one or two haplotypes were significantly concordant in CD4 decline and AIDS status within 5 years of seroconversion. No concordance was found in pairs sharing zero haplotypes. At 6-10 years after seroconversion, significant concordance of these two endpoints was also observed in the pairs sharing one haplotype. The concordant results were not explained by the use of zidovudine within the pairs. Among the individuals in this cohort, the relative hazards for CD4 decline to < 20% and for AIDS were significantly elevated for one class II haplotype (DQB1*0501, DQA1*0101, DRB1*0101). In addition, the risk for AIDS was significantly increased for two other class II haplotypes (DQB1*0603, DQA1*0103, DRB1*1300, DRB3*0202 and DQB1*0301, DQA1*0501, DRB1*1400, DRB3*0202) and significantly decreased for one haplotype (DQB1*0302, DQA1*0301, DRB1*0401, DRB4*0101).

CONCLUSIONS

These data demonstrate that HIV-1 disease progression is associated with the genes in the major histocompatibility complex that regulate the host's immune response.

Expression of E6/E7 or SV40 large T antigen-coding oncogenes in human corneal endothelial cells indicates regulated high-proliferative capacity

PURPOSE

Human corneal endothelial cells are thought to have limited capacity for proliferation. Little is known about the mechanisms that regulate the proliferation of these cells. The authors introduced oncogenes into human corneal endothelial cells to modulate proliferation. In addition, they sought to establish cell lines to facilitate study of human corneal endothelial cells.

METHODS

Early-passage human corneal endothelial cells were transduced with disabled retrovirus (pLXSN16E6/E7) coding for the human papilloma virus type 16 transforming oncoproteins E6 and E7. Early-passage cells were also stably transfected by electroporation with the pMTV-D305 plasmid vector, in which SV40 large T antigen (SV40 LTAg) mRNA expression is positively regulated by the mouse mammary tumor virus promoter. Expression of E6/E7 mRNA or SV40 LTAg mRNA in cell lines was monitored with the polymerase chain reaction. SV40 LTAg protein expression was detected by immunocytology and Western blot analysis.

RESULTS

Human corneal endothelial cells were efficiently infected with disabled retrovirus coding for E6/E7, and seven strains of cells have continued active proliferation for more than 50 population doublings (PD) (< 8 control PD). E6/E7 mRNA was expressed by each cell strain. E6/E7 transformed cells proliferate rapidly and form a monolayer of cells with a high degree of contact inhibition. Transfection with pMTV-D305 is less efficient, and only a single strain was developed. pMTV-D305-transfected endothelial cells (dexamethasone induced) proliferated at a lower rate than E6/E7-transduced cells or cells transfected with a vector (pSV3neo) in which SV40 LTAg is constitutively regulated. In the absence of dexamethasone, the proliferation of pMTV-D305-transfected cells was even slower, but cells continued to produce SV40 LTAg mRNA and protein. The latter results indicated that SV40 LTAg mRNA continued to be synthesized at significant levels in pMTV-D305-transfected cells in the absence of the inducer dexamethasone.

CONCLUSIONS

This study suggests that human corneal endothelial cells have a high capacity for proliferation. Thus, cell division is normally controlled in human corneal endothelial cells by poorly characterized, but efficient, mechanisms. Because the E6 and E7 proteins, as well as the SV40 large T antigen, specifically bind to and interfere with the activity of the retinoblastoma (RB) and p53 tumor suppressor proteins, our results suggest that these proteins have critical roles in regulating the proliferation of human corneal endothelial cells.

Goblet cell carcinoid of the appendix

BACKGROUND

Over the past 15 years, a variant of appendiceal carcinoid has been recognized which is not widely known to the general surgeon. This tumor, variously labeled adenocarcinoid or goblet cell carcinoid, has a more aggressive natural history than classic appendiceal carcinoids and requires a different surgical approach.

PATIENTS AND METHODS

A survey of the tumor registries of 10 hospitals identified 7 female and 2 male patients with goblet cell carcinoid of the appendix between 1983 and 1993. The clinical data of these patients were reviewed.

RESULTS

Median age was 58 years (range 31 to 73). Clinical presentation followed two distinct patterns: acute onset suggestive of appendicitis or chronic symptoms associated with a pelvic mass. In no case was the diagnosis suspected preoperatively or established intraoperatively. Four patients with discrete distal appendiceal tumors treated with appendectomy are alive without evidence of disease 2 to 11 years since their diagnoses. The 5 patients with diffuse appendiceal involvement all had intra-abdominal metastases. Four are dead of disease at intervals from 5 months to 2 years postdiagnosis.

CONCLUSIONS

Goblet cell carcinoids are a distinct clinical and pathologic entity with variable malignant potential. Patients with diffuse appendiceal involvement require aggressive surgery as part of multimodal therapy.

Effect of epidermal growth factor, hepatocyte growth factor, and keratinocyte growth factor, on proliferation, motility and differentiation of human corneal epithelial cells

We sought to determine the effects of exogenous epidermal growth factor (EGF), heparin-binding EGF (HB-EGF), transforming growth factor alpha (TGF-alpha), single-chain precursor hepatocyte growth factor (SC-HGF), double-chain mature HGF (DC-HGF), and keratinocyte growth factor (KGF) on proliferation, motility, and differentiation of first passage cultures of human corneal epithelial cells in serum-free chemically defined medium. The effect of EGF, HB-EGF, TGF-alpha, SC-HGF, DC-HGF, KGF or combinations of the growth factors on proliferation was measured by counting cells present after 3 weeks of culture and by immunostaining for the cell-cycle-specific nuclear proliferation antigen Ki-67. The effect of the factors on epithelial cell motility was assessed by morphometric analysis of photographs of cells migrating from confluent islands of cells. The effect of growth factors on differentiation of epithelial cells were determined by immunostaining epithelial cell islands for the keratin K3 and by Western blotting for keratin K3. EGF, alone or in combination with KGF and SC-HGF, significantly stimulated motility of epithelial cells at the periphery of confluent islands of cells and induced an elongated cell morphology. TGF-alpha, HB-EGF and DC-HGF produced motility effects similar to EGF. There was diminished proliferation of the migrating cells in response to EGF, HB-EGF, TGF-alpha or DC-HGF, while non-migrating epithelial cells in the center of confluent islands continued to proliferate in response to the growth factors. EGF, HB-EGF, TGF alpha or DC-HGF inhibited expression of the differentiation-related marker keratin K3 in epithelial cells, both at the edge and at the center of the islands. KGF stimulated proliferation of corneal epithelial cells at low density and in confluent islands of cells. KGF did not affect expression of keratin K3 or migration of epithelial cells. SC-HGF had no effect on corneal epithelial cells. These results indicate that the effects of EGF, HB-EGF, TGF-alpha and DC-HGF on corneal epithelial cell proliferation, motility and differentiation vary from those of KGF and SC-HGF. EGF, HB-EGF, TGF-alpha and DC-HGF induced changes in epithelial cell morphology and motility in cells plated at low cell density or in cells located at the edge of a confluent island. Thus, these effects appear to be dependent on the extent of cell-cell contact. The inhibitory effect of EGF, HB-EGF, TGF-alpha or DC-HGF on corneal epithelial cell differentiation, however, is independent of cell density.(ABSTRACT TRUNCATED AT 400 WORDS)

Adjunctive antimicrobial therapy for complicated appendicitis: bacterial overkill by combination therapy

Although single antimicrobials with broad-spectrum aerobic and anaerobic coverage are effective in patients with appendicitis, many general surgeons continue to use multiple agents. A prospective, double-blind, randomized trial was designed to detect any clinical correlate of in vitro susceptibility advantage of multiple antimicrobials as adjunctive therapy for 114 patients undergoing operation for complicated appendicitis. There was clinical resolution of intraabdominal infections with no occurrence of postoperative infectious complications in 90% (36 of 40) of the cefotetan group and 86% (31 of 36) of the clindamycin/amikacin group (p = 0.11). The number of patients who had changes in antibiotic therapy due to postoperative complications was higher in the clindamycin/amikacin group: five (12.5%), compared to one (2.8%) in the cefotetan group (p = 0.07). Although Bacteroides fragilis group organisms resistant to cefotetan were identified, none was responsible for the postoperative infections. Adverse drug events in 28% of the cefotetan group and 26% of the clindamycin/amikacin group consisted primarily of transient elevations of liver function tests. Monotherapy with a second-generation, broad-spectrum cephalosporin, such as cefotetan, given twice a day is an economical and effective adjunctive regimen in patients with complicated appendicitis for which operation is the definitive treatment. Aminoglycosides and other, more potent antimicrobials should be reserved for resistant organisms or nosocomial infections.

Intraoperative measurement of Javid shunt flow with transit-time ultrasound

Transit-time ultrasound methods were used to measure blood flow in 37 patients undergoing carotid endarterectomy. Internal carotid flow before (ICFbef) and after (ICFaft) endarterectomy was measured with a 6 mm perivascular probe, and Javid shunt flow (SF) was measured with a clamp-on probe. For the entire group ICFbef averaged 117 +/- 67 ml/min and ICFaft was 173 +/- 67 ml/min. Shunt flow averaged 123 +/- 51 ml/min. The differences between ICFbef and ICFaft and between SF and ICFaft were significant (ANOVA, p < 0.01) but the difference between ICFbef and SF was not. The relationship between ICFbef and SF appeared to define two groups of patients. Those in whom SF was greater than ICFbef (SF > ICFbef) had more stenosis evident on preoperative arteriograms (64.7% +/- 14.55% maximum single diameter stenosis) and a greater average increase in ICF (151% +/- 159%) than those with SF < or = ICFbef (43.3% +/- 20.9% stenosis and 34% +/- 54% increase in ICF), suggesting that the relationship between SF and ICFbef defines groups with different hemodynamic responses. The similarity between SF and ICFbef indicates that Javid shunt flow offers adequate protection from cerebral ischemia. A practical benefit of the shunt clamp-on flow probe is the ability afforded to recognize shunt occlusions.

Radiodetoxified endotoxin-induced tolerance alters monocyte but not neutrophil CD11b and CD18 expression in response to lipopolysaccharide

OBJECTIVES

To test the hypothesis that pretreatment with radiodetoxified endotoxin (RDE) may mitigate the deleterious effects of subsequent infection, in part by modifying leukocyte adhesion receptor expression, and to investigate the cellular mechanisms of endotoxin tolerance induced by RDE.

DESIGN

To assess the effect of RDE pretreatment on mortality from bacterial peritonitis, rats were implanted with an intraperitoneal, barium-fecal inoculum at intervals of 0, 1, 3, and 5 days after RDE injection. Experiments were then conducted to test the effect on leukocyte adhesion receptor expression. Two groups of mice received saline solution, and one group, RDE. After 72 hours, one group received saline solution (saline/saline group), the others, lipopolysaccharide (LPS) (saline/LPS and RDE/LPS groups). Peripheral leukocytes were obtained 1 hour after injection and were analyzed for CD11b and CD18 expression by flow cytometry.

SETTING

Laboratory animal study.

RESULTS

Survival rates were not improved in rats that were pretreated with RDE 0 and 24 hours before inoculum (0% and 7%, respectively). In rats that were pretreated 72 hours and 120 hours before inoculum, 47% (P < .01) and 60% (P < .01) survived, respectively. CD18 expression on polymorphonuclear leukocytes increased twofold in the RDE/LPS (mean +/- SEM, 300.3 +/- 32.9) and the saline/LPS (mean +/- SEM, 360.4 +/- 59.9) groups compared with controls (mean +/- SEM, 176.4 +/- 18.9) (P < .05). CD11b expression on polymorphonuclear leukocytes increased threefold in the RDE/LPS (mean +/- SEM, 91.3 +/- 8.1) and the saline/LPS (mean +/- SEM, 89.8 +/- 11.4) groups compared with controls (mean +/- SEM, 32.1 +/- 1.8) (P < .05). CD18 expression on monocytes decreased in the saline/LPS group (mean +/- SEM, 134.2 +/- 14.2) and was unchanged in the RDE/LPS group (mean +/- SEM, 200.2 +/- 17.2) compared with controls (mean +/- SEM, 217.6 +/- 16.5) (P < .05). CD11b expression on monocytes decreased in the saline/LPS group (mean +/- SEM, 25.8 +/- 2.2) and was unchanged in the RDE/LPS group (mean +/- SEM, 36.4 +/- 0.9) compared with controls (mean +/- SEM, 39.7 +/- 3.9) (P < .05).

CONCLUSIONS

Radiodetoxified endotoxin reduces mortality rates from bacterial peritonitis when given at least 72 hours prior to a bacterial inoculum. Tolerance to subsequent LPS challenge is associated with an abrogation of the reduced peripheral monocyte CD11b and CD18 expression observed in native LPS-stimulated mice but is not associated with changes in polymorphonuclear leukocyte CD11b and CD18 expression. The mechanism of the observed RDE-induced monocyte hyporesponsiveness to LPS and its possible protective effect is uncertain and requires further investigation.