Can a brief behavioural change intervention encourage hospital patients with low physical activity levels to engage and initiate a change in physical activity behaviour?

BACKGROUND

Regular physical activity (PA) reduces risk factors for chronic disease. This novel study evaluates self-reported engagement with PA in recently discharged patients, identified as having low PA levels, who agreed to participate in an in-patient behaviour change intervention.

METHOD

This exploratory study invited hospital in-patients, who were classified as 'moderately inactive' or 'inactive', to participate in a brief individual physiotherapy-led motivational interviewing (MI) behavioural change intervention. Patients were encouraged to set individual exercise and activity goals, and an appropriate programme referral was identified and agreed upon.

RESULTS

Three hundred and forty-two of 526 patients, who were screened between January 2017 and March 2018, were classified 'inactive' or 'moderately inactive'. Seventy-seven percent of patients consented to participate in the brief MI intervention (n=58 'moderately active', n=206 'inactive'). One hundred percent participants who received the brief intervention agreed to attend a PA programme. At telephone follow-up, 66% self-reported engagement in community exercise or independent PA initiatives.

CONCLUSION

This exploratory study demonstrates that a brief, MI-facilitated, behaviour change intervention is feasible and has the potential to aid PA engagement for hospital patients with low PA levels upon discharge from hospital. Considering that the 'first-step' with engagement in PA is often the biggest challenge for patients, this initiative has promise to improve PA behaviour and could be rolled out across the National Health Service (NHS).

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

An anatomical evaluation of the serratus anterior plane block

The serratus anterior plane block has been described for analgesia of the hemithorax. This study was conducted to determine the spread of injectate and investigate the anatomical basis of the block. Ultrasound-guided serratus anterior plane block was performed on six soft-fix embalmed cadavers. All cadavers received bilateral injections, on one side performed with 20 ml latex and on the other with 20 ml methylene blue. Subsequent dissection explored the extent of spread and nerve involvement. Photographs were taken throughout dissection. The intercostal nerves were involved on three occasions with dye, but not with latex. The lateral cutaneous branches of the intercostal nerve contained dye and latex on all occasions. The serratus plane block appears to be mediated through blockade of the lateral cutaneous branches of the intercostal nerves. Anatomically, serratus plane block does not appear to be equivalent to paravertebral block for rib fracture analgesia.

The captive husbandry and reproduction of the pink-eared turtle (Emydura victoriae) at Perth Zoo

In 1997, Perth Zoo acquired six pink-eared turtles (Emydura victoriae) from the wild for display in the reptile facility. There is very little documented information on pink-eared turtles in captivity. This article looks at the reproductive biology, ecology, behavior, diet, and captive husbandry of the species. Eight clutches of eggs were documented over a 2-year period with an average clutch size of 10 eggs. Egg size was recorded with three clutches incubated to hatching. Ten hatchlings were maintained for a growth and development study. Measurements of weight, carapace length, width, height, and plastron length were recorded weekly for about 12 months, and then monthly for approximately 2 years. The data were analyzed and showed positive growth curves in all animals. Sexual dimorphism was observed after 20 weeks and sexual maturity in males observed after 2 years.

Psychosocial impact of prostate cancer surgery on sexual intimacy

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Background: Prostate cancer survivors live with the day-to-day consequences of the disease and its treatment. Prostate cancer, has been labeled a “relationship disease” because it impacts both partners. Traditional research does not include psychosocial aspects of sexual well-being. We designed a retrospective survey asking patients’ and their partners’ about the physiologic and psychosocial changes experienced after prostate cancer treatment. Methods: The study design is a cross sectional retrospective mailing sent to men treated surgically for prostate cancer. Questions related to physiologic changes centered around foreplay, libido, erection, orgasm and ejaculation while emotional status, relationship/partnership quality, self image, and social support comprised the psychological questions. Of the total 47 items, 18 items assessed the above concepts in binary fashion while the remaining 29 used a Likert scale. Results: After obtaining IRB approval, we mailed consents to 368 men. Only 65 men acknowledged receiving the information and 51 consented to participate. The participants were a median age of 59.6, predominantly Caucasian (80%), and treated by prostatectomy or cryotherapy. In terms of emotional status, 20% were diagnosed with depression and 10% with anxiety since their prostate cancer diagnosis and of those 32% felt it affected their sexual status. One third of the men rated their overall sexual relationship with their partner as “poor.” Of those men, 44% also perceived their partner was supportive. Over 80% felt their partnership quality was “stable,” “strong,” and “happy.” Almost half (43%) of the men experienced a decrease in self-esteem while 16% were unhappy with their physical appearance. While few men (4%) availed themselves of support groups, 18% found the advice of other patients helpful in coping with their sexuality. The side effects were unexpected in nearly half (43%) of the men. Conclusions: These preliminary findings suggest that prostate cancer treatment may be associated with psychosocial problems related to depression, anxiety, and self- esteem that impact sexual relationships. Although prospective validated questionnaires are needed to confirm these findings, better counseling through the disease trajectory may help combat these emotional issues.

No significant financial relationships to disclose.

Survival and resource utilization in liver transplant recipients: the impact of admission to the intensive care unit

The organ allocation system for liver transplantation was recently changed to address criticisms that it was too subjective and relied too heavily on total waiting time. The new system, Model for End-Stage Liver Disease and Pediatric Model for End-Stage Liver Disease (MELD/PELD), stratifies patients based on the risk of 3-month pretransplant mortality, allocating livers thereby. There is concern that such a scheme gives priority to the sickest patients, who may not enjoy good posttransplant outcomes. The aim of the present study was to compare the outcomes of liver transplant recipients who had been admitted to the intensive care unit (ICU) to those who had not. Admission to the ICU is considered here to be another indicator of the severity of illness. Patients who underwent liver transplantation at the Cleveland Clinic between January 1, 1993 and October 31, 1998 and were at least 18 years of age were coded for liver transplantation as status 2, 2A, and 2B (n = 112). These patients fell into three groups: those who had been admitted to an ICU before transplantation (group A, n = 16), those who had been admitted to the hospital but not to an ICU (group B, n = 63), and those who were living at home and had undergone an elective transplant (group C, n = 33). Clinical and demographic information (age, sex, race, disease severity, disease etiology, and cold ischemia time) were associated with patient survival, patient/graft survival, and posttransplant resource utilization (hospital length of stay and hospital charges). Age, sex, race, etiology of disease, and cold ischemia time were similar among the three groups. Patient survival, patient/graft survival, and hospital charges were not statistically different between the three groups. The median length of stay was statistically different only between groups B and C (P =.006). Our data support the idea that if severely ill patients with end-stage liver disease are selected appropriately, liver transplant outcomes are similar to those observed among subjects who are less ill and are transplanted electively from home.

Cryptogenic cirrhosis and posttransplantation nonalcoholic fatty liver disease

Some patients diagnosed with cryptogenic cirrhosis may have "burned-out" nonalcoholic fatty liver disease (NAFL). To test this hypothesis, we used our liver transplant database (November 1984 to November 1998) to assess the incidence of NAFL in patients with cryptogenic cirrhosis after orthotopic liver transplantation (OLT). We also examined the clinicodemographic features associated with post-OLT NAFL, obtained by chart review and telephone interviews. When available, post-OLT liver biopsy specimens were reviewed blindly by a hepatopathologist according to the NAFL pathology protocol. We identified 51 patients with cryptogenic cirrhosis (mean age, 51 +/- 12 years); 60% were women, 94% were white, and 34% had type 2 diabetes mellitus (DM). Mean pre-OLT body mass index (BMI) was 27.33 +/- 5.54 kg/m(2). Twenty-five patients underwent at least 1 post-OLT liver biopsy. Post-OLT NAFL was identified in 13 patients (25.4%), whereas post-OLT nonalcoholic steatohepatitis (NASH) was seen in 8 patients (15.7%). Features associated with post-OLT NASH were pre- and post-OLT type 2 DM (P < or =.05) and an elevated fasting triglyceride level (P <.05). BMI tended to be greater in patients with post-OLT NAFL or NASH. Those who did not develop post-OLT NAFL showed a decrease in BMI. Patients with cryptogenic cirrhosis undergoing OLT resemble patients with NAFL. Post-OLT NAFL and NASH can be seen in a number of patients with cryptogenic cirrhosis. This supports the notion that some cases of cryptogenic cirrhosis represent burned-out NAFL.

Interferon alpha 2B and ribavirin in severe recurrent cholestatic hepatitis C

Severe recurrent cholestatic hepatitis C after liver transplantation has a poor prognosis and no standard therapy is currently available. Four cases of severe recurrent cholestatic hepatitis C treated with a combination of interferon alpha 2b and ribavirin are described. All four patients were transplanted for hepatitis C-related cirrhosis. The mean age at transplantation was 45 years (range 41-51 years). Three of the patients were male and one was female. All four patients had hepatitis C virus viremia before and after liver transplantation. At 2 to 23 months after liver transplantation, all four patients developed jaundice, cholestatic elevation of liver enzymes, and histopathology consistent with severe recurrent cholestatic hepatitis C. Combination of interferon and ribavirin was given with prompt virological suppression. Despite this rapid viral suppression, all four patients developed progressive graft failure with three deaths.

Agreement in pathologic interpretation of liver biopsy specimens in posttransplant hepatitis C infection

Hepatitis C virus-related disease is rapidly becoming the most common indication for orthotopic liver transplant (OLT) in the United States. Although post-OLT hepatitis C viremia is universal, 40% to 60% of patients develop recurrent chronic hepatitis C. Distinguishing recurrent chronic hepatitis C infection from acute rejection may be difficult because of overlapping histopathologic features. To improve our diagnostic accuracy we undertook a study to determine interobserver and intraobserver agreement between pathologists examining post-OLT liver biopsy specimens in patients from our transplant database. Clinical data and microscopic sections from 26 patients with hepatitis C virus-related OLT were reviewed. Biopsy specimens were obtained because of abnormal liver enzymes (21/26) or routine post-OLT follow-up (5/26), representing both early (18+/-11 days) and late (252+/-206 days) post-OLT periods. Unidentified sections were examined by an experienced pathologist in a randomly assigned order and reexamined 6 weeks later in the same fashion by the initial reviewer and a second experienced pathologist. Interobserver and intraobserver agreement was calculated using K statistic. The intraobserver agreement was 81 % with a kappa coefficient of 0.67 (P = .001). The interobserver agreement was 78% with a kappa coefficient of 0.60 (P < .001). The early post-OLT biopsy specimens (18+/-11 days) were the most difficult to interpret.

Role of angiography and embolization for massive gastroduodenal hemorrhage

The role of mesenteric angiography and embolization for massive gastroduodenal bleeding is unclear. We reviewed the records of patients who underwent angiography for acute, nonmalignant, and nonvariceal gastric or duodenal hemorrhage that was documented but not controlled by endoscopy. Fifty patients were identified over a 7-year period ending in March 1998. Only 17 patients (34%) were originally admitted to the hospital with gastrointestinal bleeding. All required treatment in the intensive care unit (mean 15 days) with a mean APACHE III score of 79 (29% predicted hospital mortality), and 32 (64%) had organ failure. A mean of 2.1 endoscopies were performed to locate the source of acute duodenal bleeding in 37 (74%) and gastric bleeding in 13 (26%). An average of 24.3 units of packed red blood cells were transfused per patient. Twenty-five patients (50%) were found to have active bleeding at angiography; all were treated by embolization as were 22 who underwent empiric embolization. Twenty-six patients (52%) were successfully treated by embolization and thus spared imminent surgery. Multiple variables were compared between those who were successfully treated by embolization and those considered failures. Time to angiography was considerably shorter (2.5 vs. 5.8 days, P<0. 017) and fewer total units of packed red blood cells were used (14.6 vs. 34, P<0.003) in those who were successfully treated. There was also a strong trend toward using fewer units of packed red blood cells for transfusion prior to angiography (11.2 vs. 17.1, P<0.08). No differences were found that could be attributed to gastric vs. duodenal sources, number of comorbid diseases, organ failure, APACHE score, age, or whether active bleeding was found at angiography. A total of 20 patients (40%) died including 9 of 17 patients operated on in an attempt to salvage angiographic failure. In summary, angiographic embolization should be performed early in the course of bleeding in otherwise critically ill patients.

Presentation and management of cystic neoplasms of the pancreas

Pancreatic cystic neoplasms are uncommon, but it is important to differentiate them from pseudocysts and ductal adenocarcinoma. A retrospective review was performed to determine distinguishing characteristics and optimal treatment. In 51 patients operated on between 1981 and 1994 at a referral center, the following cystic neoplasms were found: 20 serous cystadenomas, 10 mucinous cystadenomas, 11 mucinous cystadenocarcinomas, five cases of mucinous ductal ectasia, and five papillary cystic neoplasms. Both mucinous ductal ectasia and papillary cystic neoplasms had distinguishing features when compared to other cystic neoplasms. Mucinous ductal ectasia was seen only in men, presented with typical symptoms, and had distinctive features on endoscopic retrograde cholangiopancreatography. Papillary cystic neoplasms occurred in young women (mean age 31 years) and were larger (mean 10.3 cm). Mucinous tumors were always symptomatic, whereas 55% of serous tumors were asymptomatic (P <0.001). The overall rate of resectability was 80%, and there was one operative death (2%). Intraoperative biopsy was diagnostic in 18 (78%) of 23 cases. An actuarial 5-year survival of 52% was found for resected mucinous cystadenocarcinomas. In conclusion, papillary cystic neoplasms and mucinous ductal ectasia have distinct characteristics that differentiate them from other types of pancreatic cystic tumors. Serous cystadenoma should be considered in asymptomatic patients and these patients should be closely observed. Symptomatic neoplasms should be resected with long-term survival expected for malignant forms. (J Gastrointest Surg 1998;2:504-508.)

Laparoscopic repair of lumbar hernias

BACKGROUND

Lumbar hernias are rare defects in the posterolateral abdominal wall that may be congenital or acquired. Repairing these defects is difficult by virtue of their location and the inherent weakness of the surrounding tissues. We report a series of seven patients who had their lumbar hernias repaired laparoscopically at two institutions.

STUDY DESIGN

We retrospectively reviewed all lumbar hernias repaired laparoscopically in our institutions within the last 16 months (August 1996 to November 1997). Postoperative followup was 1-15 months.

RESULTS

Seven patients underwent laparoscopic repair. Five hernias were acquired defects and two were congenital. One to three defects were found per patient. The average size of the hernia defect was 77.8 cm2. We used a polypropylene or a polytetrafluoroethylene mesh in all patients; the average size of the mesh used was 336.4 cm2. The average length of hospital stay was 1.7 days. One patient returned with an abscess over the mesh, which necessitated removal of the graft. Otherwise, there were no complications, and the remaining six patients had no recurrences after followup of 1-14 months.

CONCLUSIONS

The laparoscopic approach is safe and effective for repairing lumbar hernias. Advantages of this approach include excellent operative visualization, decreased hospital stay postoperatively, and a solid repair without recurrence during shortterm followup.

A randomized clinical trial of ursodeoxycholic acid as adjuvant treatment to prevent liver transplant rejection

Acute rejection following orthotopic liver transplantation is a common problem despite current immunosuppressive regimens. Ursodeoxycholic acid (UDCA) has been shown in small, open-labeled studies to prevent rejection episodes, although its effects on complications such as infections, length of hospital stay, and survival have not been evaluated. We conducted a randomized, placebo-controlled, double-blind trial to determine if UDCA (10-15 mg/kg/d) added to a cyclosporine-based immunosuppressive regimen was associated with a decrease in the incidence of at least one episode of acute cellular rejection. Secondary end-points included determining differences in the total number of rejection episodes, the use of muromonab-CD3, the incidence of infections, length of hospital stay, and survival at 90 days and 1 year. Fifty-two patients were randomized, 28 to the treatment group and 24 to the placebo group. During the 3 months of the trial, there was no difference between the placebo and UDCA groups in the number of patients who were rejection-free; however, there were significantly fewer patients in the treatment group who had multiple episodes of acute rejection (0 vs. 6; P = .007). Patients in the treatment group experienced a significantly lower incidence of bacterial infections (4% vs. 29%; P = .02), shorter hospital stay (25 days vs. 34 days; P = .03), and better 90-day survival (100% vs. 83%; P = .04) and 1-year survival (93% vs. 79%). The addition of UDCA to a cyclosporine-based immunosuppressive regimen results in significantly fewer patients experiencing multiple episodes of rejection and improved survival at 90 days and at 1 year. The use of UDCA as adjuvant therapy for patients undergoing liver transplantation who are treated with a cyclosporine-based immunosuppressive regimen should be considered.

Managed obstetrical care

The current maternal/newborn care model is outdated and needs to be revised. The health care reform movement has created a window of opportunity to redefine the episode of pregnancy care and develop a more meaningful and more cost-effective model of care. The ultimate satisfaction for physicians will occur when they exert their natural control regarding the manner in which health care dollars are spent by managing the financial risk and the patient care. The optimal management of the health care dollar can only be achieved through initiation of an integrated model in which a coordinated care team supported by the appropriate risk assessment, education, prevention and wellness program, and medically necessary intensive care of the high-risk pregnancy are brought together effectively. An integrated model will give patients what they want: compassionate, convenient, comprehensive care. It will give the payers what they are looking for--appropriate care at an appropriate predicable cost and improved outcomes. Finally, it will give the providers what they want: control over the delivery medical care.

Transfection of human topoisomerase II alpha into etoposide-resistant cells: transient increase in sensitivity followed by down-regulation of the endogenous gene

We have investigated the possibility of overcoming the resistance of human brain tumour cells (HBT20) to etoposide by transferring the normal human topoisomerase II alpha (H-topo II) gene into these cells. H-topo II in a mammalian expression vector containing a glucocorticoid-inducible mouse mammary tumour virus (MMTV) promoter was transfected into etoposide-resistant HBT20 cells (HBT20-hTOP2MAM). HBT20 cells transfected with pMAMneo vector alone served as control cells (HBT20-MAM). These were stable transfections. Following a 2 h dexamethasone treatment, H-topo II mRNA expression, protein production, etoposide-induced DNA-protein complex formation and sensitivity to etoposide were increased in HBT20-hTOP2MAM cells compared with control HBT20-MAM cells and with HBT20-hTOP2MAM cells not treated with dexamethasone. However, mRNA and protein levels and cell sensitivity returned to baseline when incubation with dexamethasone was continued for 24 h. This decrease from the 2 h values could not be explained by a loss of the MMTV promoter response to dexamethasone. (H-topo II alpha promoter)-(chloramphenicol acetyltransferase) constructs containing regions -559-0 and -2400-0 were significantly down-regulated in HBT20-hTOP2MAM cells treated for 24 h with dexamethasone compared with dexamethasone-treated control cells. H-topo II mRNA stability after 24 h of dexamethasone treatment was not altered compared with that in control cells. Our data indicate that the exogenously produced H-topo II may have a negative-feedback effect on the endogenous topoisomerase II promoter, causing down-regulation of the endogenous gene.

Effect of transfection of a Drosophila topoisomerase II gene into a human brain tumour cell line intrinsically resistant to etoposide

The human brain tumour cell line HBT20 is intrinsically resistant to etoposide and does not express mdr-1 mRNA. These studies were conducted to determine whether transfecting a Drosophila (D) topoisomerase II (topo II) gene into HBT20 cells could increase their sensitivity to etoposide. A D-topo II construct in a pMAMneo vector under the control of a mouse mammary tumour virus (MMTV) promoter was transfected into HBT20 cells. The gene is inducible by dexamethasone (Dex). The growth rate of the transfected cells and percentage of the cells in G1, S and G2M was no different than the parental cells. Survival after etoposide exposure (10 microM x 2 h) was measured by colony formation. Parental cells and cells transfected by pMAMneo vector alone showed no enhanced etoposide sensitivity after 24 h of Dex stimulation. By contrast, D-topo II transfected cells were sensitised 3-fold when etoposide treatment was preceded by 24 h Dex stimulation. Northern blotting and Western blotting confirmed that Dex had induced D-topo II expression in the sensitised cells. However, in D-topo II-transfected cells increasing the duration of Dex stimulation to 48 h eliminated the sensitisation to etoposide although increased MMTV promoter activity and expression of the D-topo II gene persisted. Measurement of endogenous human topo-II mRNA and protein revealed a decrease after Dex exposure of greater than 24 h. At these distal times, the total cellular topo II levels (endogenous + exogenous) may be decreased, which may explain why increased sensitivity to etoposide could no longer be demonstrated. This model suggests that D-topo II gene transfection can sensitise de novo resistant HBT20 cells to etoposide but that the time frame of that sensitisation is limited.

Inotropic therapy in the home care setting: criteria, management, and implications

The home care clients of today are requiring more intensive i.v. therapies in their home setting. The cardiac compromised patient is a prime target for this emerging trend in home infusion therapy. The end-stage cardiac patient has been traditionally treated in the hospital acute-care setting through frequent readmissions. However, there is an increasing desire by cardiac patients and their families to administer inotropic therapies in the home. Cardiac patients receiving inotropic therapy can be successfully treated in the home using specific admission criteria and monitoring guidelines.

Is dentistry destined to follow medicine in managed care?

Our professional calling is to assist our patients in reaching and maintaining a state of good oral health. If managed care assists in that effort, that's good. However, if we can identify and eliminate poor dental HMOs and identify the quality plans, dentistry will begin to realize that keeping people well can be as financially and professionally rewarding as treating disease. Is dentistry headed down the same path as medicine? Unfortunately, the answer is not clear. What is clear is that managed care is here and will impact significantly on dentistry, both positively and negatively. An opportunity exists to mold managed care into a form that is acceptable to dentists and improve the oral health of Americans on a cost-effective basis. However, we as dentists must act, and react, in a rational and logical manner if we are to have a voice in shaping the future of dental benefits and how they will be provided.

Phorbol regulation of topoisomerases I and II in human leukemia cells. Studies in an additional cell pair sensitive or resistant to phorbol-induced differentiation

We previously reported (Zwelling et al., Cancer Res 50: 7116-7122, 1990) that etoposide-induced DNA cleavage and mRNA coding for topoisomerase II are reduced in HL-60 cells induced to differentiate by phorbol ester. Reduction of etoposide-induced cleavage and topoisomerase II message did not occur in the derived cell line 1E3 (which is resistant to phorbol-induced differentiation), implying that topoisomerase II activity may be related to the state of cell differentiation. We have extended these studies using a new phorbol sensitive/resistant cell pair, S (sensitive) and PET (phorbol ester tolerant). Phorbol ester exposure not only reduced etoposide-induced DNA cleavage and topoisomerase II mRNA in S cells but also decreased the amount of immunoreactive topoisomerase II enzyme in whole S cells. However, immunoreactive topoisomerase II extracted from the nuclei of phorbol-treated S cells was not reduced compared with that from the nuclei of untreated S cells. This suggests that topoisomerase II contained in nuclear extracts is not always representative of the total cellular enzyme. Dramatic decreases in the amount, activity, or gene expression of topoisomerase II were not observed after phorbol treatment of the resistant PET cells; this is consistent with the potential involvement of topoisomerase II in monocytoid differentiation. Levels of topoisomerase I enzyme and mRNA fell in both S and PET cells after phorbol treatment; therefore, the genes for topoisomerases I and II did not appear to be regulated coordinately.

Further characterization of an amsacrine-resistant line of HL-60 human leukemia cells and its topoisomerase II. Effects of ATP concentration, anion concentration, and the three-dimensional structure of the DNA target

The characterization of type II topoisomerases from amsacrine-sensitive (HL-60) and amsacrine-resistant (HL-60/AMSA) human leukemia cells was extended. The intercalator resistance and etoposide sensitivity of the HL-60/AMSA cells themselves were confirmed, and the stability of this pharmacologic phenotype over many hundreds of cell generations was demonstrated. Prolonging exposure of HL-60/AMSA cells to amsacrine did not alter their sensitivity relative to that of HL-60 cells. Improved methods of immunoblotting allowed clear demonstration that the topoisomerase II within these cells exhibited sensitivity and resistance characteristics that mirrored those of the cells and the isolated enzymes themselves. Additional biochemical characterization of the type II topoisomerases indicated that both enzymes relaxed supercoiled DNA in a distributive fashion and that the ATP concentrations at which optimal catalytic activity of the two enzymes was exhibited were identical. The enzymes differed, however, in their activity optima in buffers of various type and ionic strength. Furthermore, the inability of the HL-60/AMSA enzyme to exhibit enhanced DNA cleavage in the presence of amsacrine could be overcome if the DNA target molecule contained a bend cloned into its polylinker region. By contrast, a bend in a DNA plasmid containing no polylinker was resistant to amsacrine-enhanced cleavage in the presence of HL-60/AMSA topoisomerase II, as was a plasmid containing a polylinker with no bend. This suggests that an unusual DNA conformation (a bend) in a specific DNA context (a polylinker) may be a favored site for topoisomerase II action. It also suggests a mechanism by which the sites and extent of topoisomerase II activity can be controlled in cells.

Activity of two novel anthracene-9,10-diones against human leukemia cells containing intercalator-sensitive or -resistant forms of topoisomerase II

We have examined the activities of two novel aza-anthracene-9,10-diones (aza), 1-aza and 2-aza, in HL-60 human leukemia cell lines containing type II topoisomerases with different sensitivities to inhibition by other intercalating agents. The sensitive line, HL-60, was sensitive to 2-aza but not to 1-aza, whereas the resistant HL-60/AMSA was sensitive to neither agent. Measurements of 1- and 2-aza-induced, topoisomerase II-mediated DNA cross-linking in the cells revealed patterns of resistance and sensitivity that paralleled the results in the cytotoxicity assays. However, measurements of drug-induced topoisomerase II-mediated DNA cross-linking using purified HL-60 and HL-60/AMSA topoisomerase II indicated that both agents could stabilize a covalent complex between DNA and the HL-60 enzyme. HL-60/AMSA topoisomerase II resisted stabilization by either agent. This suggests that the resistance of HL-60 cells to 1-aza is not due to the inability of this drug to inhibit topoisomerase II but rather to another, undefined mechanism.

Circumvention of resistance by doxorubicin, but not by idarubicin, in a human leukemia cell line containing an intercalator-resistant form of topoisomerase II: evidence for a non-topoisomerase II-mediated mechanism of doxorubicin cytotoxicity

The novel, topoisomerase II-reactive anthracycline intercalator idarubicin (IDA) was demonstrated to produce protein-associated DNA cleavage in HL-60 human leukemia cells. Like a host of other antineoplastic intercalating agents, IDA produced this effect to a much lesser extent in HL-60/AMSA cells, a line that is primarily resistant to the intercalator amsacrine, but is cross-resistant to a variety of topoisomerase II-reactive DNA intercalating agents including IDA. This resistance is thought to be secondary to the resistance of the topoisomerase II within HL-60/AMSA cells. Surprisingly, HL-60/AMSA cells were minimally resistant to the cytotoxic and DNA cleaving actions of another anthracycline, doxorubicin (ADR). Comparing other effects of the two anthracyclines revealed that IDA, but not ADR, produced endonucleolytic cleavage, a marker of apoptosis. These results suggest that DNA intercalating anthracyclines can have different effects in human leukemia cells. In the case of IDA, drug actions were similar to those produced by the majority of intercalating agents examined in this cellular system. In the case of ADR, the ability to circumvent the resistance of HL-60/AMSA suggests additional, non-topoisomerase II-mediated mechanisms of cytolysis that may also explain the broad spectrum of clinical activity of ADR.

Relative activity of structural analogues of amsacrine against human leukemia cell lines containing amsacrine-sensitive or -resistant forms of topoisomerase II: use of computer simulations in new drug development

Anilino analogues of amsacrine showed increased activity against amsacrine (AMSA)-resistant cell lines when compared with the parent compound, but the mechanisms of amsacrine resistance in these lines were unknown (Finlay, G. J., Baguley, B. C., Snow, K., and Judd, W., J. Natl. Cancer Inst., 82: 662-667, 1990). We tested the cytotoxic and DNA-cleaving activities of two amsacrine analogues which were derivatives of 9-anilinoacridine (1'-methylcarbamate and 1'-benzenesulfonamide) against an amsacrine-resistant human leukemia cell line (HL-60/AMSA) whose resistance is due to an amsacrine-resistant topoisomerase II. Neither agent could overcome the amsacrine resistance of HL-60/AMSA. Neither agent could induce HL-60/AMSA topoisomerase II-mediated cleavage of DNA in an isolated biochemical system, although at high concentrations the two analogues could inhibit HL-60/AMSA topoisomerase II-mediated DNA strand passage. Both analogues were at least as active, if not more active, than amsacrine against amsacrine-sensitive HL-60 and its topoisomerase II. Comparison of the cellular and biochemical results with those from computer simulation of the energy-minimized structures of amsacrine, its inactive isomer o-AMSA, and the two new active analogues suggests the following possibilities: (a) the positioning of the potential topoisomerase II-binding site (1'-anilino group) of the two new drugs resembles the positioning of this site in amsacrine; (b) the HL-60 topoisomerase II has a binding site which interacts with amsacrine and the two anilino analogues but not with o-AMSA, an analogue with altered positioning of the methoxy group; (c) the HL-60/AMSA topoisomerase II interacts with reduced affinity with amsacrine and the two anilino analogues, although HL-60/AMSA topoisomerase II still interacts with the structurally distinct topoisomerase II-reactive nonintercalator, etoposide; (d) because of their higher DNA binding affinity or the greater possible positions of their side groups in comparison to amsacrine, the two analogues can, at high concentrations, inhibit the strand-passing activity of HL-60/AMSA topoisomerase II.

Identification of a point mutation in the topoisomerase II gene from a human leukemia cell line containing an amsacrine-resistant form of topoisomerase II

HL-60/AMSA is a human leukemia cell line that is 50- to 100-fold more resistant to the cytotoxic actions of the topoisomerase II-reactive intercalator amsacrine than is its drug-sensitive HL-60 parent line. Previously, we have shown that the topoisomerase II from HL-60/AMSA is also resistant to inhibition by amsacrine and other intercalating agents. We therefore sought the molecular basis for the resistance of the topoisomerase II of HL-60/AMSA and, by inference, of the HL-60/AMSA line itself. We report the cloning and sequencing of the topoisomerase II genes from both the sensitive and resistant leukemia cell lines using polymerase chain reaction technology. We have identified a single base change associated with the drug-resistant form of topoisomerase II. This mutation is present in both cloned HL-60/AMSA complementary DNA and extracted HL-60/AMSA genomic DNA. A rapid assay for this mutation in clinical samples has been developed and applied to the DNA of cells from both normal volunteers and leukemia patients. Thus far, the HL-60/AMSA genotype has not been identified in the cells from any individual, suggesting that this genotype is indeed a mutation and not an allelic form of topoisomerase II. The novel assay developed will allow a rapid search for the prevalence of this mutation in clinical samples from patients with leukemia who have relapsed following intercalator therapy.

Cross-resistance of an amsacrine-resistant human leukemia line to topoisomerase II reactive DNA intercalating agents. Evidence for two topoisomerase II directed drug actions

HL-60/AMSA is a human leukemia cell line that is 50-100-fold more resistant than its drug-sensitive HL-60 parent line to the cytotoxic actions of the DNA intercalator amsacrine (m-AMSA). HL-60/AMSA topoisomerase II is also resistant to the inhibitory actions of m-AMSA. HL-60/AMSA cells and topoisomerase II are cross-resistant to anthracycline and ellipticine intercalators but relatively sensitive to the nonintercalating topoisomerase II reactive epipodophyllotoxin etoposide. We now demonstrate that HL-60/AMSA and its topoisomerase II are cross-resistant to the DNA intercalators mitoxantrone and amonafide, thus strongly indicating that HL-60/AMSA and its topoisomerase II are resistant to topoisomerase II reactive intercalators but not to nonintercalators. At high concentrations, mitoxantrone and amonafide were also found to inhibit their own, m-AMSA's, and etoposide's abilities to stabilize topoisomerase II-DNA complexes. This appears to be due to the ability of these concentrations of mitoxantrone and amonafide to inhibit topoisomerase II mediated DNA strand passage at a point in the topoisomerization cycle prior to the acquisition of the enzyme-DNA configuration that yields DNA cleavage and topoisomerase II-DNA cross-links. In addition, amonafide can inhibit the cytotoxic actions of m-AMSA and etoposide. Taken together, these results suggest that the cytotoxicity of m-AMSA and etoposide is initiated primarily by the stabilization of the topoisomerase II-DNA complex. Other topoisomerase II reactive drugs may inhibit the enzyme at other steps in the topoisomerization cycle, particularly at elevated concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

A lack of detectable modification of topoisomerase II activity in a series of human tumor cell lines expressing only low levels of etoposide resistance

Etoposide (VP-16) resistance is expressed following in vitro exposure of HN-1 and MCF-7 human tumor cells to the drug itself or to fractionated X irradiation. VP-16-selected sublines prove cross-resistant to Adriamycin, amsacrine and actinomycin D, whilst X-ray-pretreated sublines show cross-resistance to only actinomycin D. These differential responses, in the HN-1 series, are not associated with significant differences in amounts of immunoreactive topoisomerase (topo) II, altered topo-II catalytic activity of nuclear extracts or changes in susceptibility of the topo II to VP-16- or amsacrine-induced DNA-protein cross-link formation. Therefore significant modifications in topo II appear not to be implicated in VP-16 resistance in these HN-1 sublines.

Effect of bryostatin 1 on drug-induced, topoisomerase II-mediated DNA cleavage and topoisomerase II gene expression in human leukemia cells

Unlike PMA, bryostatin 1 has been found to have a minimal effect on drug-induced topoisomerase II-mediated DNA cleavage and no effect on topoisomerase II mRNA levels. Furthermore, bryostatin 1 overcame the down-regulatory effects of PMA treatment on (1) drug-induced, topoisomerase II-mediated DNA cleavage, (2) drug-induced cytotoxicity, and (3) topoisomerase II gene expression. Thus, it is unlikely that the effects of phorbol ester treatment on topoisomerase II-mediated events are a direct consequence of protein kinase C activation per se. Rather, the results with bryostatin 1 suggest that the phorbol ester effects are related to more distal effects of phorbol ester treatment that may be related to monocytoid differentiation.

The effect of staurosporine on drug-induced, topoisomerase II-mediated DNA cleavage in human leukemia cells

Phorbol-12-myristate 13-acetate (PMA), a stimulator of protein kinase C, dramatically decreased topoisomerase II-reactive drug-induced DNA cleavage in HL-60 human leukemia cells. The effect of staurosporine, an inhibitor of protein kinase C, on drug-induced, topoisomerase II-mediated DNA cleavage was quantified in the same cells. Staurosporine decreased the magnitude of 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA)- and etoposide-induced DNA cleavage in a dose- and time-dependent fashion. Measurement of several parameters of cell proliferation revealed no clear and uniform correlation between staurosporine's inhibition of these parameters and its effects on drug-induced DNA cleavage. A direct comparison with PMA's effects on drug-induced DNA cleavage showed that whereas PMA's inhibition of etoposide-induced cleavage was much greater than its inhibition of m-AMSA-induced cleavage, the magnitude of staurosporine's effect on the cleavage produced by the two topoisomerase II-reactive drugs was similar. Thus, although PMA stimulates protein kinase C and staurosporine inhibits this enzyme, it is unlikely that the actions of either on topoisomerase II-reactive, drug-induced DNA cleavage are mediated directly via protein kinase C. Furthermore, it is likely that the mechanisms by which PMA and staurosporine inhibit topoisomerase II-reactive drug-induced cleavage are different.

Phorbol ester effects on topoisomerase II activity and gene expression in HL-60 human leukemia cells with different proclivities toward monocytoid differentiation

We examined the effects of phorbol ester treatment on topoisomerase II-mediated events in two human leukemia cell lines with different proclivities toward phorbol ester-induced monocytoid differentiation. HL-60 is the parent line that will terminally differentiate; 1E3 is a derived line that will not terminally differentiate. Within 24 h of phorbol ester treatment, etoposide-induced, topoisomerase II-mediated DNA cleavage declined 10-fold, whereas 4'-(9-acridinylamino)-methanesulfon-m-anisidide- induced DNA cleavage declined 3-fold in HL-60. In phorbol-treated 1E3, etoposide-induced DNA cleavage declined only 2-fold, whereas 4'-(9-acridinylamino)methanesulfon-m-anisidide-induced cleavage was barely affected. There was a 2- to 3-fold decline in topoisomerase II activity within the nuclear extracts from phorbol-treated HL-60 cells but not from phorbol-treated 1E3 cells. Immunoblotting experiments with anti-topoisomerase II antibodies indicated that phorbol treatment produced a structural change in the immunoreactive topiosomerase II in HL-60 nuclear extracts but produced no change in 1E3 topoisomerase II. Phorbol ester treatment also produced a decline in the level of topoisomerase II gene expression in HL-60 but not in 1E3 cells. By contrast, the cytotoxicity of etoposide in both lines was decreased following phorbol treatment. Thus, phorbols may uncouple the mechanisms linking drug-induced, topoisomerase II-DNA cleavable complex stabilization with drug-induced cytotoxicity, particularly in 1E3.

A restriction fragment length polymorphism for human topoisomerase II: possible relationship to drug-resistance

In previous studies we used Southern blotting to examine the topoisomerase II locus (on chromosome 17) in human leukemia cell lines and noted a difference in the XmnI restriction endonuclease digestion pattern between an m-AMSA-resistant line and its m-AMSA-sensitive parent line (Zwelling, L. A.; Hinds, M,; Chan, D.; Mayes, J.; Sie, K. L.; Parker, E.; Silberman, L.; Radcliffe, A.; Beran, M.; Blick, M. Characterization of an amsacrine-resistant line of human leukemia cells. Evidence for a drug-resistant form of topoisomerase II. Journal of Biological Chemistry 264:16411-16420; 1989). We now demonstrate that the variable XmnI digestion pattern represents a normal restriction fragment length polymorphism (RFLP) which is observed in subjects without malignant disease and exhibits an autosomal pattern of inheritance. These data suggest that the previously described deviation in the genomic structure of topoisomerase II in the m-AMSA-resistant cell line did not reflect a new mutation, but rather a reduction to homozygosity at the topoisomerase II locus. This reduction to homozygosity is not due to chromosomal loss, as chromosome 17-specific gene probes clearly identify two chromosome 17's in the sensitive line and four in the resistant line, using chromosome painting with a chromosome 17-specific library. Some other genetic change must be the cause of the resistance of HL-60/AMSA and its topoisomerase II to the inhibiting actions of m-AMSA.

HT1080/DR4: a P-glycoprotein-negative human fibrosarcoma cell line exhibiting resistance to topoisomerase II-reactive drugs despite the presence of a drug-sensitive topoisomerase II

HT1080/DR4 (DR4) is a doxorubicin-resistant human fibrosarcoma line that exhibits 150-fold cross-resistance to etoposide but does not overexpress P-glycoprotein (one mechanism of multiple drug resistance). We examined another possible mechanism that could explain resistance to both doxorubicin and etoposide: a quantitative or qualitative alteration in topoisomerase II, the putative nuclear target of these agents. The amount of immunoreactive topoisomerase II present in whole-cell lysates and nuclear extracts was three- to 10-fold lower in DR4 than in HT1080 cells. However, the topoisomerase II in nuclear extracts from both lines was sensitive to the effects of amsacrine (AMSA) and etoposide. Following treatment with AMSA, etoposide, and 5-iminodaunorubicin, topoisomerase II-mediated DNA cleavage in DR4 cells and nuclei was reduced compared with cleavage in HT1080 parent cells and nuclei. The difference between the HT1080 and DR4 lines in AMSA- and 5-iminodaunorubicin-induced cleavage was similar in cells and nuclei and could be due to the lower amount of DR4 topoisomerase II. By contrast, the difference between the HT1080 and DR4 lines in etoposide-induced DNA cleavage was much greater in cells than in nuclei. This finding suggested that cytosolic factors, removed from isolated nuclei, could influence the susceptibility of intact cells to the cytotoxic and DNA-cleaving actions of etoposide. The specific activities of several antioxidant enzymes, components of the cell's defense against free-radical damage that may be produced by doxorubicin or etoposide, were significantly different in HT1080 and DR4 cytosolic extracts. These differences may constitute an additional mechanism of resistance. Regardless, the magnitude of the resistance of DR4 to doxorubicin and etoposide cannot be explained solely on the basis of a topoisomerase II-related mechanism.

Characterization of an amsacrine-resistant line of human leukemia cells. Evidence for a drug-resistant form of topoisomerase II

HL-60/AMSA is a human leukemia cell line that is 100 times more resistant to the cytotoxic actions of the antineoplastic, topoisomerase II-reactive DNA intercalating acridine derivative amsacrine (m-AMSA) than is its parent HL-60 line. HL-60/AMSA cells are minimally resistant to etoposide, a topoisomerase II-reactive drug that does not intercalate. Previously we showed that HL-60 topoisomerase II activity in cells, nuclei, or nuclear extracts was sensitive to m-AMSA and etoposide, while HL-60/AMSA topoisomerase II was resistant to m-AMSA but sensitive to etoposide. Now we show that purified topoisomerase II from the two cell lines exhibits the same drug sensitivity or resistance as that in the nuclear extracts although the magnitude of the m-AMSA resistance of HL-60/AMSA topoisomerase II in vitro is not as great as the resistance of the intact HL-60/AMSA cells. In addition HL-60/AMSA cells are cross-resistant to topoisomerase II-reactive intercalators from the anthracycline and ellipticine families and the pattern of sensitivity or resistance to the cytotoxic actions of the various topoisomerase II-reactive drugs is paralleled by topoisomerase II-reactive drug-induced DNA cleavage and protein cross-link production in cells and the production of drug-induced, topoisomerase II-mediated DNA cleavage and protein cross-linking in isolated biochemical systems. In addition to its lowered sensitivity to intercalators, HL-60/AMSA differed from HL-60 in 1) the susceptibility of its topoisomerase II to stimulation of DNA topoisomerase II complex formation by ATP, 2) the catalytic activity of its topoisomerase II in an ionic environment chosen to reproduce the environment found within the living cell, and 3) the observed restriction enzyme pattern on a Southern blot probed with a cDNA for human topoisomerase II. These data indicate that an m-AMSA-resistant form of topoisomerase II contributes to the resistance of HL-60/AMSA to m-AMSA and to other topoisomerase II-reactive DNA intercalating agents. The drug resistance is associated with additional biochemical and molecular alterations that may be important determinants of cellular sensitivity or resistance to topoisomerase II-reactive drugs.

A comparison of two crisis housing alternatives to psychiatric hospitalization

This study compared outcomes for demographically matched clients four months after their admission to two short-term crisis programs. The programs provided crisis housing and case management services as alternatives to psychiatric hospitalization for clients with severe and persistent mental illness. One program met housing needs by purchasing shelter in hotels and boarding houses, and the other provided lodging in an eight-bed crisis house. In both programs, two-thirds of the clients avoided hospitalization during four-month follow-up, and both programs were effective in stabilizing clients' housing and financial situations. Clients in the purchase-of-housing program showed an increase in substance abuse problems at follow-up. Average client costs were similar in the two programs. A critical program difference was the substantially higher staff turnover in the crisis house, which was later replaced with scattered-site crisis housing.

Effect of phorbol ester treatment on drug-induced, topoisomerase II-mediated DNA cleavage in human leukemia cells

Tumor-promoting phorbol esters such as phorbol 12-myristate 13-acetate (PMA) induce the monocytoid differentiation of HL-60 human leukemia cells. The cellular receptor for PMA is protein kinase C. However, cellular events distal to protein kinase C phosphorylation are also critical steps toward differentiation. These events may include specific programs of oncogene transcription that have been associated with phorbol ester-induced leukemic cell differentiation. Recently, it has been found that topoisomerase II could be activated by protein kinase C-mediated serine phosphorylation and that PMA treatment of HL-60 cells enhanced extractable topoisomerase II from these cells. Additionally, topoisomerase II-reactive antineoplastic drugs could block PMA-induced differentiation of HL-60. This enzyme has been implicated in gene regulation, and drug-induced, topoisomerase II-mediated DNA cleavage sites have been identified within cellular oncogenes. Thus, topoisomerase II could play a critical role in the signal transduction cascade leading from PMA-protein kinase interaction to monocytoid differentiation. We have examined this relationship between topoisomerase II and PMA-induced differentiation through measurements of drug-induced, topoisomerase II-mediated DNA cleavage (via alkaline elution) in PMA-treated HL-60 cells. Etoposide-induced DNA cleavage was reduced 10-fold in HL-60 cells treated with 10 nM PMA for 24 h. Neither dimethyl sulfoxide (which produces granulocytoid differentiation) nor non-differentiation-inducing phorbol esters could produce this effect. The decreased cleavage was not due to a PMA-induced inhibition of cell-associated etoposide and was demonstrable in nuclei isolated from PMA-treated cells. The decrease was not simply related to decreased cellular proliferation rate as reflected in the inhibition of DNA synthesis because conditions leading to marked inhibition of DNA synthesis did not necessarily inhibit etoposide-induced DNA cleavage. By contrast, lower concentrations of PMA inhibited etoposide-mediated DNA cleavage disproportionately compared with PMA effects on DNA synthesis. Interestingly, PMA reduced cleavage induced by the topoisomerase II-reactive DNA intercalator 4'-(9-acridinylamino)methanesulfon-m-anisidide by 2-fold, suggesting that specific drug-DNA interactions could partially overcome the PMA-induced effect that resulted in decreased etoposide-induced, topoisomerase II-mediated DNA cleavage. Nuclear proteins in 0.35 M NaCl extracts from untreated or PMA-treated HL-60 cells were virtually identical in topoisomerase II activity and in topoisomerase II-associated drug sensitivity.(ABSTRACT TRUNCATED AT 400 WORDS)

Anion-dependent modulations of DNA topoisomerase II-mediated reactions in potassium-containing solutions

DNA binding proteins operate in an intracellular environment of low chloride concentration, yet in vitro assays of the activities of these proteins are often performed in isotonic chloride-containing solutions. Previously, the activity of bacterial DNA-binding proteins was found to be enhanced in potassium-containing solutions in which the anion glutamate (Glu) was substituted for chloride. We have extended this observation to include eukaryotic topoisomerase I and II activities. The concentration ranges over which DNA strand passing activities of these enzymes were observed was broader in KGlu than in KCl. This was also true for the topoisomerase II-mediated DNA strand passage and antineoplastic drug-dependent DNA cleavage produced by nuclear extracts from HL-60 human leukemia cells. The rate of topoisomerase II-mediated DNA strand passage was also dependent on anion moiety and concentration in potassium-containing buffers. Drug-dependent topoisomerase II-mediated DNA cleavage in intact HL-60 cell nuclei was also anion-dependent, suggesting that anion type and concentration may influence topoisomerase II-mediated events in mammalian cells as had been described for other DNA binding proteins in prokaryotic systems. This should be considered in developing biochemical assays of topoisomerase activities to reproduce intracellular conditions.