Kinetic analysis of T4 polynucleotide kinase via isothermal titration calorimetry

T4 polynucleotide kinase (T4 PNK) phosphorylates the 5'-terminus of DNA and RNA substrates. It is widely used in molecular biology. Single nucleotides can serve as substrates if a 3'-phosphate group is present. In this study, the T4 PNK-catalyzed conversion of adenosine 3'-monophosphate (3'-AMP) to adenosine-3',5'-bisphosphate was characterized using isothermal titration calorimetry (ITC). Although ITC is typically used to study ligand binding, in this case the instrument was used to evaluate enzyme kinetics by monitoring the heat production due to reaction enthalpy. The reaction was initiated with a single injection of 3'-AMP substrate into the sample cell containing T4 PNK and ATP at pH 7.6 and 30 °C, and Michaelis-Menten analysis was performed on the reaction rates derived from the plot of differential power versus time. The Michaelis-Menten constant, KM, was 13 μM, and the turnover number, kcat, was 8 s-1. The effect of inhibitors was investigated using pyrophosphate (PPi). PPi caused a dose-dependent decrease in the apparent kcat and increase in the apparent KM under the conditions tested. Additionally, the intrinsic reaction enthalpy and the activation energy of the T4 PNK-catalyzed phosphorylation of 3'-AMP were determined to be -25 kJ/mol and 43 kJ/mol, respectively. ITC is seldom used as a tool to study enzyme kinetics, particularly for technically-challenging enzymes such as kinases. This study demonstrates that quantitative analysis of kinase activity can be amenable to the ITC single injection approach.

A methylation-phosphorylation switch controls EZH2 stability and hematopoiesis

The Polycomb Repressive Complex 2 (PRC2) methylates H3K27 to regulate development and cell fate by transcriptional silencing. Alteration of PRC2 is associated with various cancers. Here, we show that mouse Kdm1a deletion causes a dramatic reduction of PRC2 proteins, whereas mouse null mutation of L3mbtl3 or Dcaf5 results in PRC2 accumulation and increased H3K27 trimethylation. The catalytic subunit of PRC2, EZH2, is methylated at lysine 20 (K20), promoting EZH2 proteolysis by L3MBTL3 and the CLR4DCAF5 ubiquitin ligase. KDM1A (LSD1) demethylates the methylated K20 to stabilize EZH2. K20 methylation is inhibited by AKT-mediated phosphorylation of serine 21 in EZH2. Mouse Ezh2K20R/K20R mutants develop hepatosplenomegaly associated with high GFI1B expression, and Ezh2K20R/K20R mutant bone marrows expand hematopoietic stem cells and downstream hematopoietic populations. Our studies reveal that EZH2 is regulated by methylation-dependent proteolysis, which is negatively controlled by AKT-mediated S21 phosphorylation to establish a methylation-phosphorylation switch to regulate the PRC2 activity and hematopoiesis.

Aqueous solubility of beryllium(II) at physiological pH: effects of buffer composition and counterions

Beryllium ion elicits p53-mediated cell cycle arrest in some types of human cancer cells, and it is a potent inhibitor of GSK3 kinase activity. Paradoxically, Be²⁺ is regarded to have almost negligible aqueous solubility at physiological pH, due to precipitation as Be(OH)₂. This study demonstrates that the interaction of Be²⁺ with serum proteins greatly increases its effective solubility. In typical serum-supplemented mammalian cell culture medium, Be²⁺ was soluble up to about 0.5 mM, which greatly exceeds the concentration needed for biological activity. Some biochemical studies require protein-free Be²⁺ solutions. In such cases, the inclusion of a specific inorganic counterion, sulfate, increased solubility considerably. The role of sulfate as a solubility-enhancing factor became evident during preparation of buffered solutions, as the apparent solubility of Be²⁺ depended on whether H₂SO₄ or a different strong acid was used for pH adjustment. The binding behavior of Be²⁺ observed via isothermal titration calorimetry was affected by the inclusion of sodium sulfate. The data reflect a "Diverse Ion Effect" consistent with ion pair formation between solvated Be²⁺ and sulfate. These insights into the solubility behavior of Be²⁺ at physiological and near-physiological pH will provide guidance to assist sample preparation for biochemical studies.

PXR, CAR and HNF4alpha genotypes and their association with pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin in Asian patients

Previously studied candidate genes have failed to account for inter-individual variability of docetaxel and doxorubicin disposition and effects. We genotyped the transcriptional regulators of CYP3A and ABCB1 in 101 breast cancer patients from 3 Asian ethnic groups, that is, Chinese, Malays and Indians, in correlation with the pharmacokinetics and pharmacodynamics of docetaxel and doxorubicin. While there was no ethnic difference in docetaxel and doxorubicin pharmacokinetics, ethnic difference in docetaxel- (ANOVA, P=0.001) and doxorubicin-induced (ANOVA, P=0.003) leukocyte suppression was observed, with Chinese and Indians experiencing greater degree of docetaxel-induced myelosuppression than Malays (Bonferroni, P=0.002, P=0.042), and Chinese experiencing greater degree of doxorubicin-induced myelosuppression than Malays and Indians (post hoc Bonferroni, P=0.024 and 0.025). Genotyping revealed both PXR and CAR to be well conserved; only a PXR 5'-untranslated region polymorphism (-24381A>C) and a silent CAR variant (Pro180Pro) were found at allele frequencies of 26 and 53%, respectively. Two non-synonymous variants were identified in HNF4alpha (Met49Val and Thr130Ile) at allele frequencies of 55 and 1%, respectively, with the Met49Val variant associated with slower neutrophil recovery in docetaxel-treated patients (ANOVA, P=0.046). Interactions were observed between HNF4alpha Met49Val and CAR Pro180Pro, with patients who were wild type for both variants experiencing least docetaxel-induced neutropenia (ANOVA, P=0.030). No other significant genotypic associations with pharmacokinetics or pharmacodynamics of either drug were found. The PXR-24381A>C variants were significantly more common in Indians compared to Chinese or Malays (32/18/21%, P=0.035) Inter-individual and inter-ethnic variations of docetaxel and doxorubicin pharmacokinetics or pharmacodynamics exist, but genotypic variability of the transcriptional regulators PAR, CAR and HNF4alpha cannot account for this variability.

Surgical anatomy of the left lateral segment as applied to living-donor and split-liver transplantation: a clinicopathologic study

OBJECTIVE

To evaluate intrahepatic vascular and biliary anatomy of the left lateral segment (LLS) as applied to living-donor and split-liver transplantation.

SUMMARY BACKGROUND DATA

Living-donor and split-liver transplantation are innovative surgical techniques that have expanded the donor pool. Fundamental to the application of these techniques is an understanding of intrahepatic vascular and biliary anatomy.

METHODS

Pathologic data obtained from cadaveric liver corrosion casts and liver dissections were clinically correlated with the anatomical findings obtained during split-liver, living-donor, and reduced-liver transplants.

RESULTS

The anatomical relation of the left bile duct system with respect to the left portal venous system was constant, with the left bile duct superior to the extrahepatic transverse portion of the left portal vein. Four specific patterns of left biliary anatomy and three patterns of left hepatic venous drainage were identified and described.

CONCLUSIONS

Although highly variable, the biliary and hepatic venous anatomy of the LLS can be broadly categorized into distinct patterns. The identification of the LLS duct origin lateral to the umbilical fissure in segment 4 in 50% of cast specimens is significant in the performance of split-liver and living-donor transplantation, because dissection of the graft pedicle at the level of the round ligament will result in separate ducts from segments 2 and 3 in most patients, with the further possibility of an anterior segment 4 duct. A connective tissue bile duct plate, which can be clinically identified, is described to guide dissection of the segment 2 and 3 biliary radicles.

Laparoscopic vs open adrenalectomy for the treatment of primary hyperaldosteronism

HYPOTHESIS

That the clinical presentations, biochemical profiles, and surgical outcomes of patients treated with laparoscopic vs open adrenalectomy for primary hyperaldosteronism are different. DESIGN, SETTINGS, PATIENTS, AND INTERVENTIONS: The medical records of 80 patients with primary hyperaldosteronism who underwent open adrenalectomy between 1975 and 1986 or laparoscopic adrenalectomy between 1993 and 1998 at the University of California-San Francisco were reviewed by a single unblinded researcher (W.T.S.).

MAIN OUTCOME MEASURES

Severity of hypertension and hypokalemia at diagnosis, their improvement after adrenalectomy, and operative complications.

RESULTS

Thirty-eight patients underwent open adrenalectomy and 42 patients underwent laparoscopic adrenalectomy. The patients who underwent open adrenalectomy had documented hypertension for a median of 5 years before surgery; all had diastolic blood pressures greater than 100 mm Hg. Laparoscopically treated patients had documented hypertension for a median of 2.5 years preoperatively, and 20 (48%) had diastolic blood pressures greater than 100 mm Hg. The median preoperative serum potassium levels for the open and laparoscopic groups were 2.6 mmol/L and 3.3 mmol/L, respectively; the mean serum aldosterone levels were 1.47 nmol/L and 1.30 nmol/L. Thirty-two (84%) of the 38 patients who underwent open surgery and 41 (98%) of the 42 patients treated laparoscopically had adrenal adenomas. The sensitivity of preoperative computed tomographic scanning for adenomas was 83% for the patients treated with open adrenalectomy and 93% for those treated laparoscopically. There were 4 postoperative complications in the open surgery group and none in the laparoscopic group. Postoperatively, 30(81%) of 37 patients (excluding 1 patient who died of adrenocortical carcinoma) in the open surgery group and 37 (88%) of 42 patients treated laparoscopically were normotensive. Post-operative values were 3.6 to 5.0 of serum potassium per liter and 3.5 to 4.9 of serum potassium per liter in the open and laparoscopic groups, respectively.

CONCLUSIONS

Patients who are treated with laparoscopic adrenalectomy for primary hyperaldosteronism are being referred with less severe hypertension and hypokalemia than patients formerly treated with open adrenalectomy. Patients treated laparoscopically had fewer postoperative complications and were equally likely to improve in blood pressure and hypokalemia. Laparoscopic adrenalectomy has become the treatment of choice for patients with primary hyperaldosteronism because of lower morbidity.

Biliary complications of reduced-organ liver transplantation

Reduced-organ liver transplantation for children is effective in lowering pretransplantation morbidity and mortality. Improvements in surgical technique have reduced vascular complications; however, biliary complications continue to account for significant posttransplantation morbidity. This investigation chronicles the incidence and type of biliary complications encountered with reduced-organ liver transplantation. Retrospective review of reduced-organ liver recipients over a 59-month period was performed, and biliary complications were classified as (1) missed biliary radicle, (2) anastomotic leak requiring revision, and (3) biliary stricture. From July 1992 to May 1997, 42 children received reduced-organ grafts: 32 living-donor, 8 cadaveric-reduced, 1 split-liver, and 1 auxiliary orthotopic liver transplant. Of the 42 grafts, 41 were Couinaud segments II/III and 1 was segments II/III/IV. Ten biliary complications were identified in 9 recipients (24%). Biliary complications included parenchymal radicle leaks, 5 (50%); biliary strictures, 3 (30%); and anastomotic leaks, 2 (20%). Although technical advances have reduced the incidence of biliary complications secondary to organ ischemia, parenchymal radicle leaks continue to be a source of morbidity for reduced-organ recipients. Planned exploration on posttransplantation day 7 was performed on the most recent 26 of the 42 total reduced-organ procedures as a mechanism to identify and treat early technical complications. Planned exploration as a routine component of reduced-organ transplantation has yielded a 15% incidence of discovered parenchymal leaks and a 5% incidence of discovered anastomotic leaks. This series underscores the necessity for improved anatomical studies to correctly identify duct territories and the development of accurate noninvasive methods to assess the biliary system preoperatively and intraoperatively in the application of reduced-organ liver transplantation.

Functional analysis of grafts from living donors. Implications for the treatment of older recipients

OBJECTIVE

Living-related liver transplantation (LRLT) has established efficacy in children. In a larger recipient, LRLT requires the use of a small graft because of limits on the donor hepatectomy.

SUMMARY BACKGROUND DATA

The minimum graft weight required for successful transplantation has not been well established, although a characteristic pattern of graft dysfunction has been observed in our patients who receive small grafts. The authors present a clinicopathologic study of small liver grafts obtained from living donors.

METHODS

Clinical and histologic data were reviewed for 25 patients receiving LRLT. In five older recipients (small group), the graft represented 50% or less of expected liver weight, whereas in 20 others (large group), the graft represented at least 60% of expected liver weight. A retrospective analysis of graft function was conducted by analyzing clinical parameters and histology.

RESULTS

In the small group, 2 of 5 grafts (40%) were lost due to poor function, leading to one patient death (20% mortality), whereas in the large group, 2 of 20 grafts (10%) were lost due to arterial thrombosis without patient mortality. Early ischemic damage related to transplant was comparable with aspartate aminotransferase 203 +/- 23 (small group) and 290 +/- 120 (large group) at 24 hours (p = not significant). Early function was significantly decreased in the small group, with prothrombin time 18.2 +/- 2.2 seconds versus 14.8 +/- 1.6 seconds (large group) on day 3 (p = 0.034). All small group patients developed cholestasis with significantly increased total bilirubin levels at day 7 (16 +/- 5.2 mg% vs. 3.7 +/- 2.7 mg%; p = 0.021) and day 14 (12.0 +/- 7.4 vs. 1.8 +/- 0.7; p = 0.021) compared with the large group. Protocol biopsies in the small group revealed a diffuse ischemic pattern with cellular ballooning on day 7, which progressed to cholestasis in subsequent biopsies. Large group biopsies showed minimal ischemic changes. Three small group patients recovered with normal liver function by 12 weeks.

CONCLUSIONS

Clinical recovery after a small-for-size transplant is characterized by significant functional impairment associated with paradoxical histologic changes typical of ischemia. These changes apparently are due to graft injury, which can only be the result of small graft size. These findings have significant implications for the extension of LRLT to adults.

Failure patterns of cryopreserved vein grafts in liver transplantation

Reports of early success with cryopreserved saphenous veins (CSV) as arterial conduits led us to develop cryopreserved iliac veins (CIV) as interposition grafts for portal vein reconstruction in living-related liver transplantation (LRLT). Despite encouraging short-term results, retrospective analysis of long-term cryopreserved vein graft performance in LRLT at our institution has revealed a high rate of late graft failures. Between July 1992 and JUly 1994, interposition grafts (CIV for portal vein interposition n=4, CSV for portal vein interposition n=3, and CSV for hepatic artery interposition n=2) were utilized in 7 LRLT. (Two transplanted organs had both CIV and CSV grafts.) Recipients included 5 children and two small adults (median: 3.5 years, range: 0.5--59 years). Posttransplant follow-up in excess of 36 months revealed portal vein (PV) and hepatic artery (HA) complications of cryopreserved grafts in each patient. PV complications included aneurysm (n=4) diagnosed at 28, 24, 18, and 1.5 mo, stricture (n=1) diagnosed at 11 mo, and thrombosis (n=1) diagnosed at 18 mo posttransplantation. All portal vein complications have been managed without retransplantation, but one (PV thrombosis) necessitated surgical shunt therapy. Each CSV hepatic artery interposition graft has been complicated by thrombosis (diagnosed at 11 days and 24 mo posttransplant) necessitating retransplantation. Based on these observations, we have adopted alternative strategies for HA and PV reconstruction. At present, 11 LRLT have been performed without cryopreserved vein conduits over 17 mo with no vascular complications. While this study does not permit statistical analysis, these results discourage the use cryopreserved iliac veins for portal interposition and cryopreserved saphenous veins for arterial interposition in liver transplantation.

Surgical and anesthetic management of patients undergoing major hepatectomy using total vascular exclusion

Total vascular exclusion (TVE) of the liver is accomplished by complete occlusion of inflow and outflow of the liver during hepatectomy. It affords the opportunity for bloodless, anatomically precise parenchymal transection but has not been widely used in this country. TVE should make it possible to treat large or unfavorably located lesions safely. To evaluate the benefit of this modality, we have examined the results of TVE in 49 major resections. Forty-nine patients with liver tumors (mean age, 50 +/- 17 years; range 3 to 75 years) were treated by the authors over 5 years with a mean age of 50 +/- 17 years (range 3-75). Thirty-five (71%) patients were females and 38 (78%) had malignant tumors (hepatocellular CA n = 15, liver metastases n = 20, other n = 3), whereas 11 (22%) had benign tumors (hemangiomas n = 7 other n = 4). Six (12%) had histological cirrhosis but normal liver function test results. Twenty two (45%) had previous surgery. Forty-seven (96%) underwent total or extended lobectomies. Two patients had segmental resection of benign tumors (one in segment 4 and one in segment 8). Mean surgical time was 4.7 hours (2.5-8.3 hours) and mean red blood cell requirement was 2.2 U (0 to 11). Twenty-two (45%) procedures were performed without transfusions. Hospital mortality rates were 0%. The mean postoperative hospital duration was 11 days (5 to 41 years). Complications occurred in 18 (36%), requiring reoperation in 1 case for wound debridement and in another for lysis of postoperative adhesions. Hepatic insufficiency occurred transiently in 2 patients with prolongation of protime and cholestasis and resolved within 4 days in 1 patient and 10 days in the other (with cirrhosis). The perception of hepatic resection as a prohibitive undertaking with high mortality rate may limit the use of resection in patients who might benefit from this modality. Our data document the effectiveness and safety of major hepatectomy even in cirrhotic patients using TVE. Expanded use of TVE and other advances in liver surgery should be considered to decrease the morbidity rate of resection and make the benefits of this therapy more widely available.

Extraluminal, transluminal, and observational treatment for vertebral artery injuries

Injury to the vertebral artery following penetrating trauma is rare and treatment is usually surgical ligation. Recent liberal use of angiography in the evaluation of penetrating neck trauma has identified increasing numbers of patients with this challenging injury. This report describes our recent experience in treating patients with vertebral artery injuries. The purposes of this study were (1) to review the outcome of our patients with vertebral artery injuries, and (2) to develop an approach for managing these patients. Sixteen patients were treated over a 9-year period. Three patients underwent emergent operative exploration for bleeding, three underwent transcatheter embolization alone, and ten were managed conservatively by close clinical observation. No deaths occurred. Ligation was performed for injuries discovered during neck exploration, however, bleeding was sometimes persistent despite proximal control. In our center, where radiological support is readily available, temporary control of bleeding by packing with hemostatic agents allowed subsequent transcatheter embolization of the injured artery. Pseudoaneurysms, arteriovenous fistulae, and extravasations discovered angiographically were usually managed by transcatheter embolization. Patients with vertebral artery narrowings or occlusions were managed by close clinical observation.

Total vascular exclusion for major hepatectomy in patients with abnormal liver parenchyma

BACKGROUND

Total vascular exclusion (TVE) of the liver has been used to increase the safety of hepatectomy and the feasibility of difficult resections. Until recently, however, concern about the detrimental effect of warm ischemia has limited the use of this technique to patients with normal liver parenchyma.

OBJECTIVE

To compare surgical outcomes of 12 patients with abnormal livers (group 1) with outcomes of 48 patients with normal parenchyma (group 2), based on the hypothesis that uncontrolled bleeding may be more detrimental than planned hepatic ischemia.

DESIGN AND SETTING

Retrospective analysis of 60 consecutive patients undergoing liver resection under TVE in a university medical center.

PATIENTS

All 10 patients with cirrhosis had albumin levels of 30 g/L or higher and normal prothrombin times preoperatively; none had ascites. Two patients with cholestasis (one with cholangiocarcinoma and one with hepatocellular carcinoma) are included in group 1.

INTERVENTION

All 12 group 1 patients and 44 of 48 group 2 patients underwent total or extended lobectomy, with TVE induced by clamping the hilum and the vena cava above and below the liver during parenchyma division.

MAIN OUTCOME MEASURES

Hospital survival and selected surgical and laboratory parameters.

RESULTS

Operative times, ischemic times, and blood loss (1975 +/- 1601 vs 1255 +/- 1291 mL) (P = .10) were comparable in both groups. Sixty-day operative mortality was zero in both groups. There was an increased rate of complications in group 1 (44% vs 17% [P = 0.06]). Transient abnormal liver function was observed in both groups. However, significant delay in restoration of normal function was observed in group 1 with respect to bilirubin levels and prothrombin time.

CONCLUSIONS

Patients with cirrhosis can undergo successful resection using TVE. This conclusion must be limited to cirrhotic patients with good liver function. The trend toward increased blood loss may reflect greater difficulties in establishing hemostasis after reperfusion in group 1. While this group appears to have a higher risk for hepatic insufficiency, successful outcomes were achieved in all cases. Prospective study will be required to define the parameters for use of TVE in cirrhosis.

Efficacy of a fibrin hemostatic bandage in controlling hemorrhage from experimental arterial injuries

OBJECTIVE

To determine if a pressure dressing containing fibrinogen and thrombin could provide more effective control of arterial hemorrhage than a pressure dressing alone in an animal model of arterial injury.

DESIGN

Randomized acute (nonsurvival) experiment in swine.

SETTING

Federal biomedical research institute.

ANIMALS

Six anesthetized Yorkshire swine.

INTERVENTIONS

Uncontrolled arterial hemorrhage was induced in anesthetized swine by creating femoral artery lacerations. Hemorrhage was controlled by a gauze bandage containing fibrinogen and thrombin, applied with 1 minute of 3.5-kg pressure. The dressings were left in place for 1 hour after the pressure was removed. The contralateral limbs received identical treatment with plain gauze dressings.

MAIN OUTCOME MEASURES

Total blood loss, mean arterial pressure, and mortality were measured after 1 hour.

RESULTS

After 1 hour, blood loss in the fibrin bandage group was 123 +/- 48 mL, compared with 734 +/- 134 mL in the control group (P = .0022). In the group treated with the fibrin bandages, there was no significant decrease in the mean arterial pressure after arterial laceration. In contrast, there was a decrease of 30 mm Hg in the group treated with gauze dressings alone. There was no animal mortality during the study period.

CONCLUSIONS

Bandages containing fibrinogen and thrombin significantly reduced the amount of blood loss and allowed mean arterial pressures to be maintained in animals with uncontrolled hemorrhage from femoral artery lacerations. A hemostatic bandage may be an important adjuvant for controlling severe extremity hemorrhage in the prehospital setting.

Morbidity and mortality following major penetrating liver injuries

OBJECTIVE

To establish the mortality and morbidity associated with major penetrating liver injuries and to describe the nature and treatment of complications related to these injuries. We postulated that there had been a trend toward less radical initial surgery, as well as an increased utilization of modern imaging techniques in both diagnosing and treating postoperative complications following penetrating liver trauma.

DESIGN

A retrospective survey of medical records and radiology files.

SETTING

A university trauma center in an urban setting.

PATIENTS

Of the 188 patients admitted to our trauma center with penetrating liver trauma between April 1988 and December 1991, 36 had major liver trauma (grades 3 through 5) and are described in this report.

MAIN OUTCOME MEASURES

The mortality rate, type of operative treatment, and the nature and treatment of complications for each grade of major liver injury.

RESULTS

The mortality rate from major liver injuries was 17%. Surgical techniques employed primarily consisted of the use of hemostatic agents and cautery, simple suturing, direct vessel ligation, and packing. Fifty-two percent of the survivors had major complications related to the liver injury itself, but only two required operative therapy. The remaining patients were successfully treated with interventional radiologic techniques.

CONCLUSIONS

The morbidity and mortality following major penetrating liver injuries remain significant. The majority of hepatobiliary complications can be successfully managed without further surgery but require the combined efforts of the surgeon and interventional radiologist.

Failure of glow-discharge polymerization onto woven Dacron to improve performance of hemodialysis grafts

PURPOSE

The ideal conduit for hemodialysis vascular access remains elusive. Autogenous fistulas and prosthetic grafts, most commonly expanded polytetrafluoroethylene (e-PTFE), have adequate long-term patency rates (60% to 80% at 1 year); however, considerable delay in their use (2 to 6 weeks) is required. The Plasma-TFE graft is a recently introduced thin-walled woven Dacron graft to which an ultrathin layer of tetrafluoroethylene is bonded through a process of glow-discharge polymerization. This process purportedly results in a graft with an internal surface of low thrombogenicity. Low thrombogenicity, combined with the healing characteristics of a woven graft, have led to claims of equivalent patency rates even when used for dialysis immediately (within 1 week) after implantation.

METHODS

This concept led us to use this new graft material in 19 fistulas (12 forearm and 7 arm) during a 1-year period.

RESULTS

Although early use was possible, the primary and secondary patency rate at 12 months was only 47.4%. Ten grafts required replacement, five within the first month and two in the second month. Attempts at fistula revision failed because of unsuccessful graft thrombectomy or exuberant intimal hyperplasia. Failure was not associated with early use. During the same time period, 28 PTFE grafts were implanted, with only four failures (primary patency 78.6%; secondary patency 85.7%; p = 0.028). The secondary patency rate was the same for Plasma-TFE grafts (47%) but improved to 85.7% for e-PTFE grafts (p = 0.005). Both groups were comparable with respect to age, diabetes, previous dialysis access procedures, and other comorbid conditions.

CONCLUSIONS

These early results have been sufficiently disappointing that we have abandoned use of this graft approved for hemodialysis by the Food and Drug Administration and cannot recommend it for other clinical indications. Nevertheless, the concept of plasma-discharge polymerization is theoretically attractive and might be useful in future graft configurations.

Calciphylaxis in secondary hyperparathyroidism. Diagnosis and parathyroidectomy

Calciphylaxis is a rare, severe complication of secondary hyperparathyroidism. Patients present with painful, violaceous, mottled skin lesions of the upper and lower extremities, which become necrotic and produce nonhealing ulcers. Gangrene of fingers and toes frequently requires amputation, produces nonhealing wounds, and can lead to sepsis and death. We reviewed the clinical course of five patients with calciphylaxis treated in our institution. The three men and two women (aged 47 to 72 years) had secondary hyperparathyroidism from chronic renal failure. All patients had severe pruritus, painful ulcers, and severe hyperphosphatemia with elevated serum calcium-phosphate product (greater than 12 mmol2/L2), but the serum parathyroid hormone levels were only moderately elevated. Most patients had medical calcification of medium and small blood vessels, and some had soft-tissue calcification visible on roentgenography. Treatment consisted of local wound care, antibiotics, phosphate-binding agents, and parathyroidectomy. Two patients died of uncontrollable sepsis. The three survivors had dramatic improvement of pain and ulcers after parathyroidectomy. Calciphylaxis is a limb- and life-threatening complication of secondary hyperparathyroidism. Diagnosis can be made by recognizing the characteristic painful skin lesions, ulcers, and gangrene of the digits, and patients should be treated with subtotal parathyroidectomy.

Cervicothoracic vascular injuries. Presentation, management, and outcome

One hundred consecutive patients with cervicothoracic vascular trauma were analyzed. The injury severity score, mechanism of injury, age, initial findings, management, and results were tabulated. There were 48 arterial and 61 venous injuries in the stable Group A patients, 11 arterial and 12 venous injuries in the unstable Group B patients, and three arterial and five venous injuries in the morbid Group C patients. Treatment included primary repair, resection with end-to-end anastomosis, or ligation. Twenty-three patients developed postoperative complications, the most common being respiratory in nature. The overall mortality rate was six per cent. Five patients died during or immediately after operation of exsanguination, and one died of ischemic brain death on the seventh postinjury day. The usefulness of preoperative angiograms, especially in the detection of arteriovenous fistulas, is important in planning the surgical approach. The overall outcome was favorable.

Nonoperative management of blunt liver injuries in adults: the need for continued surveillance

Computed tomography (CT) scanning after blunt abdominal trauma has allowed nonoperative management of selected patients with liver injuries. This report describes 52 adult patients with liver injuries who were treated without immediate surgery. Thirty-four of these hepatic injuries were relatively minor (Grade I-II), and 18 were considered major (Grade III-V). Free intraperitoneal blood in small to large amounts was evident on CT in 37 patients. There were no deaths in this series, no major complications, no known missed intra-abdominal injuries, and no delayed hemorrhage. While most liver injuries appear to heal rapidly by serial CT scans, a small percentage of these patients have residual liver defects persisting for several months and may be at risk for future complications.

Hepatic vein and retrohepatic vena caval injury

Retrohepatic venous injury presents as a rare but frequently lethal complication of trauma. The anatomic arrangement makes management of these injuries difficult at best. Operative exposure and isolation techniques ranging from cross-clamping the aorta, portal triad, suprarenal vena cava, and suprahepatic vena cava to the use of internal shunts are described in this report. Our experience from 1968 to 1987 with internal shunting techniques includes 27 patients. We have successfully resuscitated 12 patients for an acute mortality of 55%. We believe that this figure is high but compares favorably with published results. Late deaths from sepsis, disseminated intravascular coagulation, or multiple systems organ failure remain as significant causes of overall mortality. Many techniques have been successfully employed over the years in achieving vascular isolation of the liver. The methods all have their own merits, but the key factor in each is the recognition that they need to be employed. Conservative selection of patients is undoubtedly justified, but aggressive approaches should not be delayed until they are the methods of last resort.

Popliteal artery entrapment: an evolving syndrome

Popliteal artery entrapment can result in claudication and limb-threatening ischemia in the young adult. The purpose of this study was to evaluate prospectively those patients with popliteal artery entrapment. To define the syndrome, the methods used in diagnosis and the type of anatomic anomaly were established for each patient. From 1977 to 1988, 12 patients were found to have popliteal artery entrapment. The average age was 27 years, with all but three patients under age 40 years. All patients complained of calf claudication, and one had acute ischemia. The ankle pulses decreased with maneuvers in 10 patients; four patients had a resting ankle/brachial index less than one. All had diminished ankle/brachial indexes when a treadmill test was performed at 4.2 mph, 10% grade, for 10 minutes. All patients had biplanar arteriography with passive dorsiflexion and active plantar flexion. All results showed abnormal extrinsic compression or occlusion of the popliteal artery. Twenty limbs were affected; eight of 12 patients (67%) had bilateral entrapment. Type IV (37%) lesions were the most common, with type II (32%) and type III (26%) following closely. One (5%) type I lesion and no type V lesions were found. This is the largest single series of patients with popliteal entrapment in the United States. A treadmill test followed by biplanar arteriography established the diagnosis in all patients. Bilateral involvement was twice that reported in previous studies. Popliteal artery entrapment should be considered in the young adult with claudication and may be seen with greater frequency in an increasingly active population.

Reduction in HLA-DR, HLA-DQ and HLA-DP expression by Leu-M3+ cells from the peripheral blood of patients with thermal injury

Monocytes that bear HLA Class II antigens, such as HLA-DR, HLA-DQ, or HLA-DP, are obligatory for many cell-mediated immunological processes. Patients with thermal injury suffer from hypoimmunity and are at risk for developing life-threatening septic episodes. To determine whether an alteration in expression of HLA Class II antigens is involved in the defect, monocytes from the peripheral blood of burn patients and controls were double-stained with anti-Leu-M3 and either anti-HLA-DR, HLA-DQ, or HLA-DP monoclonal antibodies. As analysed by flow cytometry the percentage of Leu-M3+ monocytes from the peripheral blood from patients and controls was the same. The percentage of Leu-M3+ monocytes bearing the HLA Class II antigens and the density of antigen on the monocytes, however, was significantly reduced post-burn compared with controls. In nearly all cases these changes were detected as early as 24 h post-burn before any drug therapy was implemented. In-vivo re-expression of normal levels of HLA Class II coincided with patient recovery. In-vitro exposure of post-burn Leu-M3+ cells to IFN-gamma for 72 h restored HLA Class II expression to control levels. It is possible that the reductions in HLA Class II expression may be involved in the general immunosuppression that follows thermal injury.

A step-wise logistic regression analysis of hepatocellular carcinoma. An aspiration biopsy study

Fine needle aspiration biopsy (FNAB) has become a popular method to diagnose mass lesions of the liver. Although several reports have listed FNAB criteria to be used to diagnose both primary and metastatic tumors of the liver, none have separated key cytologic criteria from secondary criteria. We reviewed the FNAB smears from 35 patients with proven hepatocellular carcinoma and 74 patients with proven metastatic tumors in the liver. All specimens were coded as to the presence or absence of the following variables: polygonal cells with centrally placed nuclei; well-defined, granular cytoplasm; large nucleoli; small cytoplasmic vacuoles; large cytoplasmic vacuoles; bile; polymorphonuclear leukocytes; malignant cells separated by sinusoidal vessels; endothelial cells surrounding tumor cell clusters; multinucleated tumor giant cells; basophilic intracytoplasmic inclusions; eosinophilic intracytoplasmic inclusions; and intranuclear cytoplasmic inclusions. A step-wise logistic regression analysis was performed on the data to determine the variables predictive of hepatocellular carcinoma. The statistical analysis selected polygonal cells with centrally placed nuclei, malignant cells separated by sinusoidal capillaries, and bile as the key cytologic criteria for hepatocellular carcinoma. Endothelial cells surrounding tumor cell clusters and intranuclear cytoplasmic inclusions were selected as secondary criteria by this analysis.

The effect of verapamil on cerebral cortical and spinal cord blood flow during proximal descending thoracic aortic occlusion

The mechanism of central nervous system (CNS) protection during proximal descending thoracic aortic cross-clamping (PDTAC) for aortic surgery using calcium channel blocking agents is not known. In order to determine the effect of verapamil on CNS blood flow during PDTAC, we calculated cerebral cortical (CC), proximal spinal cord (PSC), and distal spinal cord (DSC) blood flow using the microsphere method in Grade I beagles. Flow calculations were obtained at baseline (pre-PDTAC), following mobilization of the proximal descending aorta for 5-8 cm by ligating 3-5 pairs of intercostal arteries (ICA), during PDTAC (45 min), and during maximal reperfusion. Two groups were studied: 1) control (Cont) untreated (n = 5); 2) verapamil (Ver) treated (0.4 mg/kg IV just before PDTAC and just before reperfusion) (n = 5).

CONCLUSIONS

I) Proximal ICA ligation produces no compromise to SC blood flow. II) Verapamil may protect the CNS by: 1) maintaining cerebral autoregulation during reperfusion; and 2) dampening hyperperfusion of the distal SC during reperfusion.

Post-ischemia immunosuppression in a miniature swine model

Yucatan miniature swine were the experimental model used to examine the effect of ischemia-injury on post-ischemic monocyte (MO) and immune function. Monocyte plasminogen activator (PA) was depressed while MO tissue factor activity was increased. The ability of porcine monocytes to generate a primary in vitro antibody forming cell (AFC) response to sheep red blood cells (SRBC) also was depressed by ischemic injury. The mechanism by which ischemic injury modulated immunosuppression appeared to be through generation of immunosuppressive serum substances.

Primary aldosteronism: changing concepts in diagnosis and management

Unilateral adrenalectomy for benign causes of primary aldosteronism is an established procedure. The established surgical cure for aldosterone-producing adenoma justifies a thorough preoperative evaluation. No single test accurately identifies aldosterone-producing adenomas in patients with primary aldosteronism. However, a useful algorithm combines postural studies, computerized axial tomography, and adrenal vein catheterization for selective hormonal assay, if computerized axial tomography is negative or equivocal and the suspicion of aldosterone-producing adenoma is high. If an adrenal mass is present and biochemical studies suggest a diagnosis of aldosterone-producing adenoma, resection of the affected gland from a limited unilateral approach is indicated. Cure can be expected in 80 percent of cases. In the uncommon circumstance that the adrenal tumor was not an aldosterone-producing adenoma but a hyperplastic nodule, these patients may still be cured or more easily controlled with antihypertensive medications. Thirty-eight patients who underwent unilateral adrenalectomy are presented and discussed.

Management of injuries to the porta hepatis

The management of injuries to the porta hepatis is challenging and controversial. Although definitive, anatomic reconstruction of injured ductal or vascular structures is optimal, porta hepatis injuries are universally accompanied by injuries to other organs (3.6 in this series), which often precludes initial repair. Moreover, frequent injury to the inferior vena cava, aorta, or other major blood vessels in addition to the structures of the porta hepatis results in these injuries being treated in conjunction with exsanguinating hemorrhage. For that reason, control of hemorrhage is the initial management priority, with the initial operation requiring expeditious, if less than anatomically exact, operations. Eighteen of 31 patients survived porta hepatis injury. Hepatic artery injuries were treated by ligation. Complex injuries to bile ducts frequently required enteric-ductal anastomoses as secondary procedures. Of 29 patients with portal vein injuries, six were treated by ligation, 22 by lateral repair, and one with splenic vein interposition graft. As in earlier reports, the structure of the porta hepatis associated with the highest morbidity and mortality rates when injured was the portal vein.

Dextran as a modulator of immune and coagulation activities in trauma patients

Low Mr dextran has been utilized as a prophylactic therapy in treatment of coagulopathy. There is evidence that monocyte dysfunctions are important contributors to hypercoagulability episodes, as well as to immunoincompetence post-trauma. Dextran is a known monocyte modulator. Consequently, we evaluated the efficacy of dextran infusion in moderating immune dysfunction, monocyte aberrations, and hypercoagulability episodes. Twenty-eight trauma patients were randomly divided into two groups. One group of 15 received dextran at 1 g/kg wt/24 hr for 5 days in addition to standard resuscitation and treatment. The control or nontreated patient group received only standard treatment. Trauma patients in the two groups were retrospectively matched by injury severity score (ISS) to ensure comparability. Blood samples were collected daily for some studies and at 3-day intervals for other assays. In vivo coagulation status was evaluated by assessing the changes in intravascular fibrinopeptide A (FPA). Immune reactivity to the mitogen phytohemagglutinin (PHA) was also evaluated. Both monocyte production of plasminogen activator (PA) and monocyte production of procoagulant activity (PCA) have been shown to correspond to and be augmented by monocyte-T lymphocyte interactions. Consequently, monocyte production of plasminogen activator and procoagulant activity were assessed as measures of monocyte immune activity as well as indicators of monocyte function in controlling the balance between fibrinolysis and coagulation. Only patients with ISS of greater than 25 experienced significant immune, coagulation, or monocyte aberrations. Of those having an injury severity score (ISS) score of 25-35, all of the control and two of the dextran patients had significant perturbations in their immune and monocyte functions.(ABSTRACT TRUNCATED AT 250 WORDS)

Selective nonoperative management of blunt liver injury using computed tomography

Computed tomographic (CT) scans are used to evaluate victims of blunt trauma for abdominal injury when reasons for immediate laparotomy are not present. Twenty-four patients whose CT scans showed liver injuries that were small parenchymal lacerations or intrahepatic hematomas were managed without laparotomy. Intra-abdominal blood was absent or estimated to be less than 250 mL in volume. None of the patients were in shock; six patients required transfusions, none for acute abdominal bleeding. None of these patients subsequently required laparotomy or showed hepatobiliary problems at a follow-up examination less than one year later. Five follow-up scans showed varying degrees of resolution. Two patients died of severe head injury, but the liver injury did not contribute to the cause of death. Other patients with more severe blunt liver injury who were treated nonoperatively developed significant complications that required delayed surgery. It seems that patients with limited liver injury diagnosed by CT scan and selected by strictly applied criteria can be managed safely without laparotomy in a setting where rapid evaluation and treatment of any potential complication is available.

Determinants of survival after vena caval injury. Analysis of a 14-year experience

The records of 70 patients with vena caval injuries who were treated from 1970 through 1983 were reviewed to define factors determining patient survival. Fifty-two percent of patients survived, with the highest mortality in patients with blunt or shotgun injuries. The primary determinants of survival were the mechanism and type of injury, the initial BP, the hemodynamic response to fluid resuscitation, the location of the vena caval injury, the presence of multiple other vascular and solid organ injuries.

The role of packing and planned reoperation in severe hepatic trauma

Liver lacerations are the most common intra-abdominal injury that leads to death, and control of hemorrhage remains the primary problem in lowering mortality from severe hepatic trauma. We retrospectively reviewed operative trauma cases in which liver packing and planned reoperation were used as temporizing measures in hemodynamically unstable patients. These cases were compared to patients closely matched for age, sex, type of trauma, and associated injuries but who did not undergo liver packing and planned reoperation. Preliminary data support our contention that liver packing and planned reoperation is a valuable adjunct for the management of hemorrhage from severe hepatic injury without incurring increased morbidity or mortality. This technique is useful for the experienced trauma surgeon to arrest hemorrhage and gain hemodynamic stability before attempting definitive care and for the community hospital surgeons who after gaining hemodynamic control would like to transfer the patient to a tertiary care facility.

Hepatocellular carcinoma: assessment of resectability by computed tomography and ultrasound

A retrospective review of the CT and ultrasound scans from examinations of 30 patients who had hepatocellular carcinoma (hepatoma) was undertaken with special emphasis placed on evaluation of hepatic distribution of tumor, vascular invasion, and extrahepatic spread. Although both CT and ultrasound detected hepatoma in 29 of 30 patients (96%), CT showed more extensive hepatic parenchymal involvement in eight of the patients. Vascular invasion was seen more frequently with ultrasound than with CT. Invasion into the main portal vein was seen by ultrasound in 11 of 30 patients (37%). Extrahepatic spread of tumor was much more frequently detected by CT and was present in 21 of 30 patients (70%). A reasoned approach to the diagnostic workup of hepatomas that will minimize invasive procedures and unnecessary surgery is presented.

Oriental cholangitis

Oriental cholangitis is a poorly understood syndrome consisting of intrahepatic pigment stone formation with chronically recurrent exacerbations and remissions. Endemic to Asia, it is being encountered more frequently in the United States due to increased immigration of asians. Twenty-one patients with oriental cholangitis (9 men and 12 women), 19 to 84 years of age, all of whom immigrated from asian countries, were treated between 1970 and 1983. All had histories of episodic abdominal pain, most with jaundice, chills, and fever. Laboratory results were nonspecific but frequently included leukocytosis and hyperbilirubinemia. All patients were operated on with 15 having cholecystectomy, common duct exploration, and a bilioenteric anastomosis. E. coli was cultured from specimens obtained from the biliary tracts of all patients, and 13 patients had more than one organism. Four patients had a previous history of parasitic infection, and four different patients had parasites identified in the biliary tract intraoperatively. Early recognition and appropriate operation will decrease morbidity and mortality.

Hepatocellular carcinoma. Changing concepts in diagnosis and management

We studied 86 cases of hepatocellular carcinoma treated between 1968 and 1982. All other liver tumors were excluded. There were 73 male and 13 female patients (average age, 59 years). The most frequent symptoms were pain (73%), weight loss (56%), and increased abdominal girth (23%). The alpha 1-fetoprotein level was elevated in 23 of 32 patients, and the hepatitis B surface antigen was positive in 15 of 36. Significant differences in the hematocrit reading and total bilirubin and total protein levels were found between those patients with resectable and unresectable tumors. Forty-six patients underwent laparotomy, with a resection rate of 48%. There were six right hepatic lobectomies, four left hepatic lobectomies, and 12 trisegmentectomies . The long-term survival in patients who underwent laparotomy and biopsy only was 4.2 months, while those who underwent resection had an average longevity of 18.7 months (the longest was 11.5 years). Using new imaging techniques, the extent of tumor involvement and operability can be determined with greater accuracy. Criteria for resectability include (1) the absence of vena caval occlusion, (2) the lack of spread between lobes, (3) the absence of portal vein obstruction, and (4) the lack of extrahepatic metastasis.

Morbidity and mortality in hepatic trauma. A 5 year study

The records of 443 cases of liver trauma operated on at San Francisco General Hospital from 1976 to 1981 were reviewed. Forty-two percent of the injuries were due to blunt trauma, 32 percent to stabbings, and 26 percent to gunshot wounds. Seventy-two percent of the patients were treated by simple repair and only 8 percent of patients had to undergo major resection. Infections and pulmonary problems were the most common complications, and the overall morbidity was 38 percent. Associated injuries occurred in 84 percent of patients. Our overall mortality was 9 percent; mortality for blunt trauma was 14 percent, for gunshot wounds 8 percent, and for stab wounds 2.8 percent. Most deaths were intraoperative (58 percent), with the primary cause of death being exsanguination. Multiple organ failure accounted for most of the postoperative deaths. Our 5 years study and comparison with previous studies reaffirms our belief in a conservative approach to the traumatized patient with liver injury. Utilizing the aforementioned principles, we have managed to show a continual decrease in mortality in spite of treating a more severely traumatized group of patients. We believe that continued improvement in mortality and morbidity is possible through the prevention of trauma, adherence to our basic guidelines, and the implementation of new technological advances now on the horizon.

Atrial-caval shunting (ACS) after trauma

Since 1968 the atrial-caval shunt (ACS), along with inflow occlusion at the porta hepatis, has been used at San Francisco General Hospital in 18 trauma patients to control massive hemorrhage from the inferior vena cava, hepatic veins, or liver. Thirteen patients died from irreversible shock. Five patients survived their initial injuries; one of them died 45 days later from the complications of shock and sepsis. No patients survived who sustained blunt trauma and were admitted in cardiac arrest. Only one of ten patients with BP less than 70 mm Hg after resuscitation survived, whereas four of eight with BP greater than 70 mm Hg survived. ACS was used to control caval injuries in seven patients (one survivor), severe hepatic parenchymal fractures in four patients (two survivors), and combined hepatic and caval injuries in seven patients (two survivors). Survivors had an average of 5.75 associated injuries; nonsurvivors had 3.8. No complications of ACS occurred in the surviving patients.

Management of acute civilian vascular injuries

Vascular trauma continues to be an exciting and formidable challenge to surgeons. Increasing numbers of survivors of major vascular trauma such as suprarenal aortic and caval injuries are being reported in the literature. Successful repair of venous injuries rather than ligation is being achieved in significant numbers of cases. Combined team approaches utilizing new techniques of microvascular surgery and orthopedic fixation have dramatically improved the results of revascularization in extremity injuries and subsequent restoration of limb function.

Generation of tissue factor by patient monocytes: correlation to thromboembolic complications

Thromboembolic complications are often a common pathological consequence of severe soft tissue trauma. Recent demonstration that monocytes (M0) produce tissue factor (TF) has led to the suggestion that these TF producing M0 might play a role in coagulopathy. We have previously demonstrated that trauma patients with splenectomy develop aberrant monocyte function and this patient group is also known to be at high risk of hypercoagulability episodes. This paper is an initial report on the use of M0 TF as an indicator of and/or correlated to clotting episodes. Monocytes isolated form the Ficoll-Hypaque purified mononuclear cells of 46 normal individuals, 17 trauma patients and 6 surgical controls were assayed at 3 day post-injury intervals for their levels of TF activity. Changes in monocyte TF activity were correlated to increases in the fractional catabolic rate (FCR) of 125 I-fibrinogen. Trauma patients were retrospectively divided into those whose FcR was elevated to a level indicative of coagulopathy and those whose FCR levels were not associated with coagulation abnormalities. All trauma patients who exhibited significantly increased FCR experienced thromboembolic episodes and had monocytes whose TF activity was increased an average of 300% (mean = 47 units vs mean = 12 units) over surgical controls. These increase in monocyte TF activity occurred at 6-13 days post injury and preceded clinical manifestation of coagulopathy by 4-6 days. The increased monocyte TF activity demonstrated in this study was significantly correlated to detection of pathologically increased FCR (R = 0.850) and compared to other indices of hypercoagulability.

Injuries sustained from high velocity impact with water: an experience from the Golden Gate Bridge

Over 720 persons are reported to have died jumping from the Golden Gate Bridge. A review of 100 consecutive autopsies showed that, in the majority of cases, massive pulmonary contusion, pneumothorax, laceration or perforation of the heart, great vessels, or lungs by displaced ribs were the causes of immediate death. Irreparable fractures of the liver or spleen were the most common abdominal injuries. The persons fatally injured appeared to have entered the water in a horizontal position, experiencing maximal deceleration. In contrast, six survivors entered the water feet first with more gradual deceleration. These survivors remained conscious but sustained similar injuries of lesser degree; only one sustained rib fractures. Fifty per cent had fractures of the liver or spleen requiring operative therapy. Fifty per cent sustained lung contusions and subsequent pneumothoraces. Suspicion of underlying injuries to the liver, spleen, and lungs is essential during resuscitation of those who survive impact with water.

Is splenic salvage safe in the traumatized patient?

Thirty-three patients with splenic injuries were treated with splenic salvage techniques. These patients were seriously injured trauma victims, often with multiple organ system damage. Hemostasis of the spleen was achieved with topical agents in 26 patients. Six patients required suture repair, with one hemisplenectomy. The postoperative complication rate was 37%; however, none of the complications could be attributed to the splenic repair. No patient required reoperation for control of bleeding. There were no subphrenic abscesses, and delayed rupture of the spleen could not be established. Splenic salvage can be done safely in selected patients. Young patients, those with isolated splenic injuries, and those in whom the repair will not unduly complicate the operation should be considered for this procedure.

Management of portal vein injuries

Injuries to the portal vein are associated with a high mortality because of a high incidence of concomitant injury to surrounding structures and refractory shock. Repair of the portal vein injury is often difficult or impossible because of massive hemorrhage. The key to successful management of a portal vein injury is rapid blood volume resuscitation and obtaining rapid and adequate exposure. The optimal exposure for repair consists of reflection of the hepatic flexure of the colon with mobilization of the root of the mesentery, pancreas, and duodenum. Lateral venorrhaphy is the preferred method of management, but in hemodynamically unstable patients, ligation of the portal vein is an acceptable method of treatment.