Comparison of 2 Doses for ACTH Stimulation Testing in Dogs Suspected of or Treated for Hyperadrenocorticism

BACKGROUND

Lowering the cosyntropin dose needed for ACTH stimulation would make the test more economical.

OBJECTIVES

To compare the cortisol response to 1 and 5 μg/kg cosyntropin IV in dogs being screened for hyperadrenocorticism (HAC) and in dogs receiving trilostane or mitotane for pituitary-dependent HAC.

ANIMALS

Healthy dogs (n = 10); client-owned dogs suspected of having HAC (n = 39) or being treated for pituitary-dependent HAC with mitotane (n = 12) or trilostane (n = 15).

PROCEDURES

In this prospective study, healthy dogs had consecutive ACTH stimulation tests to ensure 2 tests could be performed in sequence. For the first test, cosyntropin (1 μg/kg IV) was administered; the second test was initiated 4 hours after the start of the first (5 μg/kg cosyntropin IV). Dogs suspected of having HAC or being treated with mitotane were tested as the healthy dogs. Dogs receiving trilostane treatment were tested on consecutive days at the same time post pill using the low dose on day 1.

RESULTS

In dogs being treated with mitotane or trilostane, the 2 doses were pharmacodynamically equivalent (90% confidence interval, 85.1-108.2%; P = 0.014). However, in dogs suspected of having HAC, the doses were not pharmacodynamically equivalent (90% confidence interval, 73.2-92.8%; P = 0.37); furthermore, in 23% of the dogs, clinical interpretation of test results was different between the doses.

CONCLUSIONS AND CLINICAL RELEVANCE

For dogs suspected of having HAC, 5 μg/kg cosyntropin IV is still recommended for ACTH stimulation testing. For dogs receiving mitotane or trilostane treatment, a dose of 1 μg/kg cosyntropin IV can be used.

Evaluation of thyroid-stimulating hormone, total thyroxine, and free thyroxine concentrations in hyperthyroid cats receiving methimazole treatment

Background

Iatrogenic hypothyroidism (IH) after treatment of hyperthyroidism can impair renal function. No study compared the efficacy of measurement of serum free thyroxine by equilibrium dialysis (fT4ed) or thyroid‐stimulating hormone (TSH) concentrations for monitoring cats receiving methimazole.

Objectives

To (1) compare the ability of total T4 and fT4ed concentrations in conjunction with TSH to define thyroid function in hyperthyroid cats receiving methimazole, (2) determine the prevalence of IH in cats receiving methimazole, and (3) examine the relationship between thyroid axis hormones and serum creatinine concentration.

Animals

One hundred and twenty‐five serum samples from hyperthyroid cats receiving methimazole and total T4 concentrations ≤3.9 μg/dL.

Methods

Total T4, fT4ed, and TSH concentrations were measured to evaluate thyroid status and serum creatinine concentration was measured to assess renal function. A low total T4 or fT4ed concentration in combination with an increased TSH concentration defined IH.

Results

Forty‐one cats (33%) had increased TSH concentrations. Of cats with total T4 and fT4ed concentrations below the reference range, 68% and 73%, respectively, had TSH concentrations above the reference range. Only 18% of cats with a normal TSH concentration had an increased serum creatinine concentrations as compared to 39% of those with increased TSH concentrations (P < .001).

Conclusions

Free T4ed does not identify more cats with potential IH as compared to total T4. The IH prevalence was approximately 20%. Measurement of TSH may be more helpful in indicating that azotemia, if present, is at least in part related to IH. Investigation is needed to define TSH assay utility in identifying possible subclinical IH.

Vascular anomalies: classification, imaging characteristics and implications for interventional radiology treatment approaches

The term vascular anomaly represents a broad spectrum of vascular pathology, including proliferating vascular tumours and vascular malformations. While the treatment of most vascular anomalies is multifactorial, interventional radiology procedures, including embolic therapy, sclerotherapy and laser coagulation among others, are playing an increasingly important role in vascular anomaly management. This review discusses the diagnosis and treatment of common vascular malformations, with emphasis on the technique, efficacy and complications of different interventional radiology procedures.

Effect of trilostane and mitotane on aldosterone secretory reserve in dogs with pituitary-dependent hyperadrenocorticism

Background

Maximal aldosterone secretion in healthy dogs occurs 30 minutes postadrenocorticotropin (ACTH; 5 μg/kg IV) stimulation. The effect of trilostane and mitotane on aldosterone at that time is unknown.

Objectives

To assess the effect of trilostane and mitotane in dogs with pituitary‐dependent hyperadrenocorticism on aldosterone secretory reserve. To determine if aldosterone concentration correlates with electrolyte concentrations.

Animals

Serum collected from 79 client‐owned dogs and 33 stored samples.

Methods

Client‐owned dogs had ACTH stimulation tests with cortisol concentrations measured at 0 and 60 minutes and aldosterone concentrations measured at 0, 30, and 60 minutes. Stored samples had aldosterone concentrations measured at 0 and 60 minutes. Ten historical clinically healthy controls were included. All had basal sodium and potassium concentrations measured.

Results

The aldosterone concentrations in the mitotane‐ and trilostane‐treated dogs at 30 and 60 minutes post‐ACTH were significantly lower than in clinically healthy dogs; no significant difference was detected in aldosterone concentration between 30 and 60 minutes in treated dogs. However, a significantly higher percentage of dogs had decreased aldosterone secretory reserve detected at 30 minutes than at 60 minutes. At 30 minutes, decreased secretory reserve was detected in 49% and 78% of trilostane‐ and mitotane‐treated dogs, respectively. No correlation was detected between aldosterone and serum electrolyte concentrations.

Conclusions and Clinical Importance

Decreased aldosterone secretory reserve is common in trilostane‐ and mitotane‐treated dogs; it cannot be predicted by measurement of serum electrolyte concentrations. Aldosterone concentration at 30 minutes post‐ACTH stimulation identifies more dogs with decreased aldosterone secretory reserve than conventional testing at 60 minutes.

Colonic necrosis subsequent to catheter-directed thrombin embolization of the inferior mesenteric artery via the superior mesenteric artery: a complication in the management of a type II endoleak

The optimal management of endoleaks after endovascular repair of abdominal aortic aneurysms remains to be established. In this report, we describe a persistent side-branch, or type II, endoleak 1 year after endograft implantation treated with catheter-directed embolization of the aneurysm sac and the inferior mesenteric artery via the superior mesenteric artery, with embolization agents including thrombin, lipiodol, and gelfoam powder. Shortly after the embolization procedure, colonic necrosis developed in the patient, manifested by peritonitis, which necessitated a partial colectomy. This case underscores the devastating complication of colonic ischemia as a result of catheter-directed embolization of the inferior mesenteric artery in the management of an endoleak.

Intra-arterial thrombin injection of an ascending aortic pseudoaneurysm complicated by transient ischemic attack and rescued with systemic abciximab

Thrombin injection as a means of inducing thrombus formation has recently received wide attention as an alternative treatment for pseudoaneurysm. We present a case of a 67-year-old man in whom a large mycotic pseudoaneurysm developed in the ascending aorta because of sternal osteomyelitis and mediastinitis after coronary artery bypass grafting. Transcatheter intra-arterial thrombin injection was performed, and it successfully induced pseudoaneurysm thrombosis. However, the procedure was complicated by a sudden transient ischemic attack caused by thrombus propagation into the cerebral circulation. Complete thrombus dissolution in the cerebral circulation with the resolution of neurologic symptoms was achieved by means of intravenous abciximab.

Early experience with the bifurcated Excluder endoprosthesis for treatment of the abdominal aortic aneurysm

PURPOSE

This report describes our initial experience with the modular, bifurcated Excluder endoprosthesis and its safety and efficacy in the primary endovascular repair of infrarenal abdominal aortic aneurysms (AAAs).

METHODS

AAAs (mean diameter, 58.2 +/- 14.3 mm) were repaired in 19 patients with this device between March 1999 and January 2000. The mean age of patients was 71.8 +/- 8.4 years (range, 57-86 years). This modular device was inserted through an 18F introducer sheath placed in one femoral artery, and the contralateral artery was cannulated with a 12F introducer sheath. All procedures were performed in a standard operating room with angiographic capabilities.

RESULTS

Endograft deployment was successful in all patients. The average surgical time was 135 +/- 37 minutes, with a mean blood loss of 229 +/- 138 mL. In eight patients, the use of either aortic or iliac extenders was required for enhanced sealing or additional length. An external iliac artery dissection occurring at the time of endograft insertion was successfully treated with a Wallstent. Type II leaks initially found to be present by means of intraoperative completion angiography had spontaneously thrombosed by the 1-month follow-up computed tomography scan. There was one perioperative death (5.3%). Complications included superficial wound infections (n = 3) and a nonfatal myocardial infarction (n = 1). The mean length of hospital stay was 2.9 +/- 1.2 days, and only six patients required intensive care. Endoleaks were seen in four patients (21%) by means of the 30-day computed tomography scan; three of these endoleaks had spontaneously sealed at the time of the 6-month follow-up examination (5.5% 6-month endoleak rate). Aneurysm size did not increase in the patients with leaks.

CONCLUSION

The Excluder endoprosthesis was an effective means of excluding an infrarenal AAA from the systemic circulation in this selected group of patients. The smaller sheath sizes may increase the pool of potential candidates. Further study of this device is warranted, and continued assessment of the long-term durability of the device will be necessary.

Endovascular revascularization of renal artery stenosis: technical and clinical results

PURPOSE

The natural history of renal artery stenosis is progression with subsequent deterioration of kidney function and development of renovascular hypertension. Percutaneous transluminal renal angioplasty is effective in the treatment of nonostial lesions but less effective for ostial stenoses. Because of the poor technical success experienced with percutaneous transluminal renal angioplasty, stenting of ostial stenoses is becoming the standard of endovascular care. In this retrospective study we analyzed the technical and clinical outcomes after renal artery stenting in 73 consecutive patients.

PATIENTS AND METHODS

From July 1992 to January 1999, 88 Palmaz stents were deployed in 85 renal artery stenoses in 73 patients, with a mean age of 67.9 +/- 9.4 years. Twelve patients (16%) underwent bilateral stent placement. Atheromatous lesions were the most prevalent (99%: 82% ostial, 16% nonostial). Most stents were implanted for suboptimal balloon dilation (52%) or dissection (24%). Mean percent stenosis was 86% +/- 12%. Renal insufficiency (creatinine level > or = 1.5 mg/dL) was present in 50 (68%) patients, and uncontrolled hypertension (systolic > or = 160 mm Hg or diastolic > or = 90 mm Hg with more than two medications) was present in 57 (78%).

RESULTS

Primary technical success was achieved in 89%. At the initial procedure, three additional stents were placed for residual stenoses, and urokinase was used to treat one intraprocedural stent thrombosis, resulting in an assisted primary technical success rate of 94%. Major complications occurred in 9.1% of stents placed: access artery thrombosis (n = 4), renal artery extravasation (n = 1), renal artery thrombosis (n = 1), and hematoma requiring operation (n = 2). Long-term clinical data were available on 69 (95%) patients at 20 +/- 17 months. Overall, a significant decrease in systolic and diastolic pressures (P <.001) and reduction of medication (P <.01) were noted without a change in renal function (P = NS). Angiography was performed on 22 patients at 11.3 +/- 10.3 months for persistent or worsening renal function or hypertension or for other reasons; 10 patients had significant restenoses in 14 renal arteries.

CONCLUSION

Our retrospective analysis demonstrates that endovascular stenting of renal artery stenosis in patients with poorly controlled hypertension or deteriorating renal function is a safe and effective alternative treatment to surgical management.

Aggregate changes in severe cognitive impairment among older Americans: 1993 and 1998

OBJECTIVES

This study explored whether improvements in cognitive functioning occurred during the 1990s among older Americans and investigated several possible explanations for such changes.

METHODS

Using the 1993 Asset and Health Dynamics of the Oldest Old study (N = 7,443) and 1998 Health and Retirement Survey (N = 7,624), this study examined aggregate changes in the proportion of the noninstitutionalized population aged 70 and older with severe cognitive impairment. Impairment was measured for self-respondents using a modified version of the Telephone Interview Cognitive Screen; for proxy respondents, ratings of memory and judgment were used. Logistic regression was used to investigate potential explanations for aggregate changes.

RESULTS

The percentage of older Americans with severe cognitive impairment declined from 6.1% in 1993 to 3.6% in 1998 (p < .001). The decline was statistically significant among self-respondents but not among those with proxy interviews. Improvements between 1993 and 1998 were not explained by shifts in demographic and socioeconomic factors or by changes in the prevalence of stroke, vision, or hearing impairments.

DISCUSSION

As a group, older persons, especially those well into their 80s, appear to have better cognitive functioning today than they did in the early 1990s.

Endovascular revascularization of renal artery stenosis in the solitary functioning kidney

The treatment of renal artery stenosis by angioplasty and stenting is an effective and accepted alternative to surgery for the treatment of renovascular hypertension and preservation of renal function. We report the technical and clinical outcomes of renal artery stenting in patients with a solitary functioning kidney and renal artery stenosis. From October 1993 to November 1999, 30 stents were placed in the renal arteries of 27 patients (mean age 72+/-8 years) with a solitary functioning kidney and azotemia. The mean diameter renal artery stenosis was 86+/-14%. The mean preprocedure serum creatinine (Cr) level was 3.0+/-1.5 mg/dL (range 1.5-7.5 mg/dL), arterial blood pressure was 171+/-29/85+/-13 mmHg, and the number of antihypertensive drugs was 2.9+/-1.1. Indications for stenting were suboptimal balloon dilation (n = 16), intimal dissection (n = 6), and restenosis following angioplasty (n = 5). Atherosclerotic ostial lesions were present in 25 (93%) of 27 renal arteries. This represents the largest series of renal artery stenting in patients with a solitary functioning kidney, and demonstrates this treatment modality to be a relatively safe alternative to conventional surgery in this high-risk patient group. Most (74%) of the patients in this series had improved or stabilized renal function. Further efforts to define preprocedural indicators of success are necessary to identify the patients who may benefit from revascularization of their solitary kidney.

Hydrodynamic thrombectomy system versus pulse-spray thrombolysis for thrombosed hemodialysis grafts: a multicenter prospective randomized comparison

PURPOSE

To evaluate the safety and efficacy of a hydrodynamic thrombectomy system in a prospective, multicenter randomized comparison with pulse-spray thrombolysis in hemodialysis grafts.

MATERIALS AND METHODS

Nine centers enrolled 120 adult patients with recently (</=14 days) thrombosed hemodialysis grafts. Graft venography was used to confirm occlusion in 62 patients randomly assigned to thrombectomy and 58 to thrombolysis. For thrombolysis, a mixture of 5,000 U of heparin and 250,000 U of urokinase was distributed throughout the thrombus, first to the venous then to the arterial graft end. For thrombectomy, the catheter was passed in the same sequence. Technical success was removal of 80% or more of thrombus. Clinical success was technical success plus the ability to dialyze. Also assessed were total procedure time, thrombus treatment time, procedure-related blood loss, other complications, and 30- and 90-day outcomes.

RESULTS

Patient demographics were comparable. Technical success rates were 95% (59 of 62) for thrombectomy and 90% (52 of 58) for thrombolysis (P: =.31). Clinical success rates were 89% (55 of 62) and 81% (47 of 58), respectively (P: =.24). At 30 days, 69% (43 of 62) and 66% (38 of 58), respectively, could be dialyzed through the graft (P: =.70); at 90 days, the rates were 40% (25 of 62) and 41% (24 of 58), respectively (P: =.91). None of these differences or those for procedure-related blood loss and early and late complications were statistically significant. Thrombus treatment times of 16.8 minutes for thrombectomy and 23.4 minutes for thrombolysis were significantly different (P: <.01).

CONCLUSION

The hydrodynamic thrombectomy system is at least as efficacious and safe as pulse-spray thrombolysis but shortens thrombus treatment time.

Contribution of chronic conditions to aggregate changes in old-age functioning

OBJECTIVES

This study explored the role of various chronic conditions in explaining recent improvements in functioning among older Americans.

METHODS

We used the Supplements on Aging to the 1984 and 1994 National Health Interview Surveys to examine changes among Americans 70 years and older in reports of chronic conditions and functional limitations. We decomposed functioning changes into condition-related components, controlling for demographic shifts.

RESULTS

The percentage of older Americans with upper- and lower-body limitations declined from 5.1% and 34.2%, respectively, in 1984 to 4.3% and 28.5% in 1995, and the average number of lower body limitations decreased. During the same period, reports of 8 of 9 chronic conditions increased, but many of these conditions had less debilitating effects on functioning. Reductions in the debilitating effects of various chronic conditions--particularly arthritis--are important in explaining declines in limitations experienced by older Americans.

CONCLUSIONS

Earlier diagnosis and improved treatment and management of chronic conditions, rather than prevention, may be important contributing factors to improvements in upper- and lower-body functioning among older Americans.

Determinants of mortality in patients with advanced cirrhosis after transjugular intrahepatic portosystemic shunting

BACKGROUND & AIMS

Transjugular intrahepatic portosystemic shunt (TIPS) placement is effective in the treatment of complications of portal hypertension. This study evaluated the predictors of mortality in a group of cirrhotic patients with advanced liver disease after placement of TIPS.

METHODS

A retrospective analysis of all patients undergoing TIPS placement over a 21/2-year period was undertaken.

RESULTS

Fifty-six patients had TIPS placement for variceal hemorrhage, 49 for refractory ascites, and 24 for hepatic hydrothorax (total, 129). Of 21 variables available before TIPS placement, variceal hemorrhage requiring emergent TIPS placement (relative risk [RR], 37.5; 95% confidence interval [CI], 5.4-259) and bilirubin concentration > 3.0 mg/dL (RR, 5.4; 95% CI, 1.4-10.2) were independent predictors of 30-day mortality. Variceal hemorrhage requiring emergent TIPS placement (hazard ratio [HR], 5.1, 95% CI, 2. 2-9.1), alanine aminotransferase level > 100 IU/L (HR, 2.5; 95% CI, 1.2-5.5), bilirubin level > 3.0 mg/dL (HR, 2.6; 95% CI, 1.1-4.6), and pre-TIPS encephalopathy unrelated to bleeding (HR, 2.2; 95% CI, 1.2-4.8) independently predicted death during the follow-up period. A model was developed that separated the patients into 3 groups with significantly different survival rates.

CONCLUSIONS

A clinical index consisting of 4 pre-TIPS variables can reliably predict outcome after TIPS.

The role of education in explaining and forecasting trends in functional limitations among older Americans

Using the Survey of Income and Program Participation, we document the importance of education in accounting for declines in functional limitations among older Americans from 1984 to 1993. Of the eight demographic and socioeconomic variables considered, education is most important in accounting for recent trends. The relationship between educational attainment and functioning has not changed measurably, but educational attainment has increased greatly during this period. Our analysis suggests, all else being equal, that future changes in education will continue to contribute to improvements in functioning, although at a reduced rate.

Prophylactic angioplasty reduces thrombosis in virgin ePTFE arteriovenous dialysis grafts with greater than 50% stenosis: subset analysis of a prospectively randomized study

PURPOSE

To determine if prophylactic percutaneous transluminal balloon angioplasty (PTA) can extend patency in functioning virgin ePTFE arteriovenous hemodialysis grafts.

MATERIALS AND METHODS

The results of a prospectively randomized study of 64 patients with greater than 50% stenosis of functioning ePTFE arteriovenous hemodialysis grafts who were blindly assigned to be treated with PTA (treatment group) or observed without treatment (control group) were subjected to statistical subset analysis. Within this group were 21 patients (virgins) who had never undergone surgery, PTA, or thrombolysis. Eight patients had been assigned to the treatment group and 13 to the control group. The virgin groups were well matched as to age, sex, and risk factors. The virgin treatment group versus virgin control group had 1.63 versus 1.46 stenoses per patient and 61.3% versus 63.3% average percentage stenosis per lesion, respectively. Stenoses were treated with PTA 27 times (average, 3.4 per patient) in the virgin treatment group. Primary study patency began at the time of randomization and ended with graft thrombosis or nonfunction.

RESULTS

Among the 32 patients randomized to treatment with PTA, study patency was significantly increased (P > .0001) and the incidence of graft thrombosis significantly decreased (P = .0151) in the eight-patient virgin subset when compared with the 24-patient nonvirgin subset of the treatment group. During the 81.3 patient-dialysis-year study period, patency in the virgin-treatment versus virgin-control groups, respectively, was terminated by thrombosis in two versus nine, by death in two versus two, and cadaveric renal transplant in one versus zero. There was a statistically significant prolongation of study patency (P = .0349) and a reduction of graft thromboses, 0.10 versus 0.44 thromboses per patient-dialysis year, in the virgin-treatment group compared to the virgin-control group.

CONCLUSION

Patency after PTA of ePTFE hemodialysis grafts is significantly affected by previous interventions. Prophylactic PTA of stenoses greater than 50% in functioning virgin ePTFE arteriovenous hemodialysis grafts can significantly extend their patency. PTA should be included as an important treatment option in this patient population.

Understanding trends in functional limitations among older Americans

OBJECTIVES

This report documents trends in functional limitations among older Americans from 1984 to 1993 and investigates reasons for such trends.

METHODS

We applied logistic regression to data for noninstitutionalized Americans aged 50 years and older from the Survey of Income and Program Participation. We focused on 4 functional limitation measures unlikely to be affected by changes in role expectations and living environments: reported difficulty seeing words in a newspaper, lifting and carrying 10 pounds, climbing a flight of stairs, and walking a quarter of a mile.

RESULTS

We found large declines in the crude prevalence of functional limitations, especially for those 80 years and older. Generally, changes in population composition explained only a small portion of the downward trends. Once changes in population composition and mobility-related device use were considered for difficulty walking, significant improvements in functioning remained for the 65- to 79-year-old group.

CONCLUSIONS

Changes in population composition, device use, survey design, role expectations, and living environments do not appear to account completely for improvements in functioning. We infer that changes in under-lying physiological capability--whether real or perceived--likely underlie such trends.

Hypercalcemia and hypermagnesemia

Hypercalcemia and hypermagnesemia occur infrequently in small animal patients. Specific clinical signs usually do not accompany these electrolyte disorders, and their presence is often recognized only after reviewing serum chemistry profile results. The etiologies, clinical signs, and therapies for each electrolyte disorder are discussed in this article. Treatment of these disorders is aimed at correcting the underlying disease process and enhancing the removal of calcium or magnesium from the body. In severe cases, rescue therapies and resuscitative measures are required to stabilize the patient.

Cost efficacy of duplex surveillance and prophylactic angioplasty of arteriovenous ePTFE grafts

Poor patency of arteriovenous ePTFE grafts remains a major clinical problem. Prophylactic balloon angioplasty of stenoses has been claimed to prolong graft patency and has been widely introduced into practice. In this manuscript we report the cost incurred in application of such a program involving graft surveillance and prophylactic angioplasty of ePTFE graft stenoses >50% diameter. All patients in a single dialysis unit with ePTFE bridge grafts were subject to a surveillance duplex ultrasound and those with a perigraft stenosis of >50% then underwent angiography. Those patients confirmed to have a stenosis >50% within the graft, were randomized to prophylactic percutaneous transluminal angioplasty (PTA) versus no intervention (observation). Patients were followed every 3 months with ultrasound and those in the treatment group with recurrent stenosis (>50%) were subject to repeat PTA. The outcome was thrombosis. Relevant charges were considered to be: initial duplex screening of the entire ePTFE dialysis group; professional and technical fees for angiography and angioplasty; follow-up duplex scanning; repeat angioplasty; and costs of lytic therapy for an intraprocedure lysis. In the treatment and observation group the 6-month patencies were 69% +/- 7% and 70% +/- 7%, respectively. Twelve-month patencies for the treatment and observation groups were 51% +/- 6% and 47% +/- 4%. There was no significant difference between these two groups (p = 0.97), with an 80% confidence limit for detection of a difference >20%. Cost for duplex screening of all patients in the dialysis unit with ePTFE grafts was $40,440 (@ $337 each x 120 patients). Total charges for initial angiography was $178. Angioplasty charges were $143,040. Cost of the follow-up duplex ultrasound scanning in the treated group was $32,352. Charges for repeat angiograms in those with recurrent stenoses were $83,682 (professional fee $1733 + $229; technical fee + $820; equipment charges x 32 x 0.94). One patient required urokinase therapy for an occlusion following PTA. The overall charge for treating the 32 patients in the treatment arm of this study was $440,834, there was net improvement in patency. A policy of generic graft surveillance and prophylactic is expensive and does not lead to improved patency. Until an effective intervention is defined by prospective randomized trial, surveillance duplex scanning cannot be justified.

Disruption of the G1/S transition in human papillomavirus type 16 E7-expressing human cells is associated with altered regulation of cyclin E

The development of neoplasia frequently involves inactivation of the p53 and retinoblastoma (Rb) tumor suppressor pathways and disruption of cell cycle checkpoints that monitor the integrity of replication and cell division. The human papillomavirus type 16 (HPV-16) oncoproteins, E6 and E7, have been shown to bind p53 and Rb, respectively. To further delineate the mechanisms by which E6 and E7 affect cell cycle control, we examined various aspects of the cell cycle machinery. The low-risk HPV-6 E6 and E7 proteins did not cause any significant change in the levels of cell cycle proteins analyzed. HPV-16 E6 resulted in very low levels of p53 and p21 and globally elevated cyclin-dependent kinase (CDK) activity. In contrast, HPV-16 E7 had a profound effect on several aspects of the cell cycle machinery. A number of cyclins and CDKs were elevated, and despite the elevation of the levels of at least two CDK inhibitors, p21 and p16, CDK activity was globally increased. Most strikingly, cyclin E expression was deregulated both transcriptionally and posttranscriptionally and persisted at high levels in S and G2/M. Transit through G1 was shortened by the premature activation of cyclin E-associated kinase activity. Elevation of cyclin E levels required both the CR1 and CR2 domains of E7. These data suggest that cyclin E may be a critical target of HPV-16 E7 in the disruption of G1/S cell cycle progression and that the ability of E7 to regulate cyclin E involves activities in addition to the release of E2F.

Central venous stenosis in the hemodialysis patient: incidence and efficacy of endovascular treatment

Central venous stenosis occurs as a complication of central venous catheterization and significantly complicates delivery of dialysis through arteriovenous grafts in the ipsilateral upper limb. This report includes two separate studies. Functioning expanded polytetrafluorethylene grafts have been prospectively evaluated using duplex scanning and angiography performed in all patients with stenoses > 50%. From this, it has been prospectively established that the incidence of unsuspected central venous stenoses in patients with functioning grafts is 29%. In the second part of the report, the authors' experience in the treatment of 25 central venous stenoses with percutaneous angioplasty and stent placement has been retrospectively reviewed. Initial technical success rate was 88%. Primary patency was 84% at 1 month, 42% at 6 months, and 17% at 1 year. Mean primary patency was 5.7 months. Stents were placed in five patients. Prevention of central venous stenosis by avoiding subclavian catheterization is optimal. Balloon angioplasty provides short-term patency, but it is the only option in most cases. The role for endovascular stent placement remains to be defined but early results are not optimistic.

Prophylactic balloon angioplasty fails to prolong the patency of expanded polytetrafluoroethylene arteriovenous grafts: results of a prospective randomized study

PURPOSE

Maintenance of hemodialysis access grafts represents an enormous social and clinical problem. Current grafts and graft salvage techniques are inadequate. Consequently, there has been increasing interest in the use of minimally invasive catheter techniques to prophylactically treat stenoses in functioning arteriovenous grafts. Prophylactic balloon angioplasty has been widely suggested as prolonging assisted primary patency. We have performed a prospective randomized trial to compare patients who underwent percutaneous transluminal angioplasty (PTA) for graft stenoses > 50% with a control group that received no intervention. Our hypothesis was that to be efficacious a minimal benefit of 20% prolongation in patency would be necessary.

METHODS

Color flow duplex scanning was used to detect > 50% stenoses in functioning expanded polytetrafluoroethylene grafts. Patients were then subjected to confirmatory angiographic evaluation. Those who had angiographic stenoses > 50% were randomized to balloon angioplasty or observation. Patients were followed-up with duplex scanning every 2 months. Statistical analysis was performed using the Kaplan-Meier technique. Although demographically the patient groups were well matched, there were more prior interventions and concurrent central stenoses in the treatment group. Outcomes were graft thrombosis, graft dysfunction that precluded dialysis, and six or more PTA procedures within 18 months.

RESULTS

In the treatment and observation groups, the 6-month patency rates were 69% +/- 7% and 70% +/- 7%, respectively. The 12-month patency rates for the treatment and observation groups were 51% +/- 6% and 47% +/- 4%, respectively. There was no significant difference between these two groups (p = 0.97), with an 80% confidence limit for detection of a difference greater than 20%.

CONCLUSIONS

This study demonstrates that a generic approach of PTA to treat all polytetrafluoroethylene grafts with stenoses > 50% does not prolong patency and cannot be supported.

Oncogenesis of mammary glands, skin, and bones by polyomavirus correlates with viral persistence and prolonged genome replication potential

A correlation between polyomavirus-induced oncogenesis and viral persistence on the one hand and/or prolonged genome replication potential on the other was established with respect to their respective organ distributions. Prolonged replication potential is defined as the capacity of a genome to replicate in a given organ from the time of infection up to the onset of oncogenesis. This conclusion was derived following intraperitoneal infection of BALB/c mice with wild-type strain A2. Viral genomes were used as parameters of persistence and replication and were detected by Southern blotting and PCR analysis. The major tumor target organs (mammary gland, skin, and bone), which have not been previously analyzed for persistence, were compared with other, non-tumor-prone organs (kidney, liver, lung, spleen, and salivary gland). A progressive loss of viral genomes was observed in all tissues as a function of time postinfection; however, genomes were shown to persist through 20 weeks postinfection in the mammary glands, skin, and bones to an extent similar to that in the previously described kidneys (D. J. McCance, J. Virol. 39:958-962, 1981; W. P. Rowe, J. W. Hartley, J. D. Estes, and R. J. Huebner, Natl. Cancer Inst. Monogr. 4:189-209, 1960). Thus, tumors arise among organs that sustain a persistent infection, but not all such organs develop tumors (e.g., the kidney). The capacity of organs to support de novo replication at various ages, including the age reached when the first tumors are detected, was also determined using a 3-day infection period for ages between 0 and 7 weeks. For all organs tested, a higher level of genomes was observed in organs of mice infected as neonates than in those infected after the age of 3 weeks. However, marked organ-specific differences were seen in the degree and timing of loss of replication. In particular, viral genome replication, although reduced, was maintained in the mammary glands, skin, and bones of adult animals, in contrast to the kidneys. We conclude that organ-specific oncogenesis correlates with two organ-specific parameters: persistence of viral genomes and prolonged viral genome replication potential. This may reflect a requirement for continued viral genome replication and/or gene expression for tumorigenesis. In turn, these parameters may be linked to the tissue-specific continued capacity for cellular division.

Transjugular intrahepatic portosystemic shunt for the management of severe venoocclusive disease following bone marrow transplantation

Hepatic venoocclusive disease (VOD) is a common, life-threatening complication of bone marrow transplantation (BMT). Portal hypertension is usually present and accounts for many of the clinical manifestations of this syndrome. We describe the results of transjugular intrahepatic portosystemic shunt (TIPS) for the management of VOD after BMT TIPS was performed in six patients with histologically confirmed VOD who had progressive jaundice and ascites. Portal hypertension was improved by TIPS in all patients (mean portal pressure gradient before TIPS, 20.2 +/- 4.6 vs. 6.7 +/- 1.9 mm Hg post-TIPS, P < .004). Three patients who underwent TIPS late in the course of VOD did not demonstrate any clinical improvement after TIPS and expired within 2 weeks of the procedure. The remaining three patients had less advanced disease and demonstrated decreases in serum bilirubin, improvement in coagulopathy, and decreased ascites after TIPS. Two patients subsequently expired, one with persistent histological changes of VOD. The lone survivor continues to do well with resolution of ascites, jaundice, and coagulopathy as of her last outpatient visit. TIPS was an effective method for portal decompression in patients with VOD after BMT, and was associated with clinical improvement in some patients. However, these effects may be transient and may not improve overall survival.

Third degree atrioventricular block and acquired myasthenia gravis in four dogs

Third degree atrioventricular block was diagnosed in 4 dogs with acquired myasthenia gravis (serum acetylcholine receptor antibody titer > 0.6 nmol/L). All 4 dogs had megaesophagus. Two dogs also had mediastinal thymomas, which were resected. One dog with thymoma received a permanent pacemaker at the same time that it underwent thymectomy; the other did not develop third degree atrioventricular block until 3 months after thymectomy. Both dogs with thymoma died of severe aspiration pneumonitis within 3 months after surgery. The third dog received a permanent pacemaker and was treated with pyridostigmine bromide, but also died of aspiration pneumonitis 1 month after the pacemaker was implanted. The fourth dog was treated with prednisolone and pyridostigmine bromide and improved, but did not become clinically normal. Because third degree atrioventricular block as well as myasthenia gravis can cause signs of weakness, acquired myasthenia gravis should be considered in dogs with idiopathic cardiac conduction disturbances. Likewise, an ECG should be evaluated in dogs with acquired myasthenia gravis.

Hematologic emergencies

The most common life-threatening hematologic emergencies include hemorrhage and severe anemia. Successful treatment of these conditions depends on the emergency veterinarian having a thorough understanding of the possible etiologies of these conditions, and a systematic approach to diagnosis and therapy. Use of blood component therapy can be a life-saving technique in these patients. The goal of this article is to familiarize the emergency veterinarian with a systematic approach to the diagnosis and treatment of hematologic emergencies.

Transjugular intrahepatic portal systemic shunt for the management of symptomatic cirrhotic hydrothorax

OBJECTIVE

To investigate the safety and effectiveness of performing transjugular intrahepatic portal systemic shunt (TIPS) for the management of symptomatic cirrhotic hydrothorax in patients with advanced cirrhosis.

METHODS

TIPS was performed by standard technique after portal vein patency had been established by ultrasound. Portal-hepatic vein pressure gradient was determined before and after placement of the shunt. A portal-hepatic vein gradient of less than 12 mm Hg was the treatment goal.

RESULTS

Five patients underwent TIPS placement over an 11-month period. Despite use of diuretics, the patients had required a median of seven thoracenteses (range 2-11) for control of symptoms preceding placement of the shunt. A TIPS was placed without serious complications in all five patients. In two patients, insertion of the shunt was associated with no further need for thoracentesis. The other three patients had recurrent need for thoracentesis. These three patients were found to have occluded shunts which were rendered patent by angioplasty and/or urokinase. Subsequently, two required no further thoracentesis, whereas, in the other patient, the need for thoracentesis was decreased dramatically.

CONCLUSIONS

TIPS appears to be a safe and useful technique for the management of patients with symptomatic cirrhotic hydrothorax that is refractory to medical therapy. Recurrence of the pleural effusion after placement of TIPS may be an indication of shunt occlusion.

Polytetrafluoroethylene aorta-vena cava graft for hemodialysis: report of a case

In children with chronic renal failure, vascular access for hemodialysis is difficult because of the small size of the vessels and the requirement for substantial blood flow through the fistula or graft. As the child grows older, the ease of constructing a satisfactory access usually increases as the vessels increase in size. Unfortunately, this increased ease is often offset by the paucity of suitable access sites because the larger peripheral sites have already been used with only transient success. We report a child with chronic renal failure since 1 month of age with no peripheral sites available because of prior failed procedures who underwent placement of polytetrafluoroethylene limbs to the aorta and vena cava at the age of 6 years. He has continued on hemodialysis for the past 4 1/2 years with this technique of vascular access.

Effects of sex steroids on myocardial anoxic resistance

Eight treatment groups of CD strain castrate male or female rats were injected daily with cottonseed oil (sham), testosterone propionate (50 micrograms/100 g body wt), estradiol benzoate (7 micrograms/100 g body wt), or a combination of both steroids dissolved in cottonseed oil. These physiologic replacement dosages of sex steroids, determined by bioassay procedures, were injected in a 0.1-ml bolus of cottonseed oil daily (intraperitoneally) for 16 weeks. Myocardial anoxic resistance was quantified by means of an in vitro right ventricular strip preparation that evaluated the ability of the isolated right ventricle to maintain contractions in response to electrical pacing at 1 Hz after 10 min of anoxia. While this parameter was elevated 2- to 3-fold in the estrogen-treated groups of male and female castrates compared with the sham (oil)-injected groups, neither testosterone treatment alone nor combination steroid treatment produced anoxic resistance values that differed significantly from those of the sham-injected animals. Thus, although estrogen alone may afford anoxic protection to the myocardium, testosterone is able to abolish this hormone-induced protection.

Renal vein renin analysis: limitations of its use in predicting benefit from percutaneous angioplasty

Two hundred forty-four consecutive patients (mean age 61 years), including 123 who had technically valid renal vein renin (RVR) analysis and 121 without RVR data, underwent technically successful percutaneous renal artery angioplasty (PTRA). They were retrospectively examined to evaluate the utility of RVR analysis in identifying renal hypertension (RVH), predicting benefit from PTRA, and determining if the lack of knowledge of renin levels significantly affected clinical outcome after PTRA. Abnormal RVR values were associated wtih clinical benefit after PTRA in 62 of 93 patients (67% sensitivity, 20% specificity, 72% positive predictive value). Clinical improvement following PTRA occurred in 31 of 37 patients with normal pre-PTRA RVR values (16% negative predictive value). RVR analysis correctly identified 86 of 117 patients with renovascular hypertension (74% sensitivity, 16% negative predictive value). Improved blood pressure (BP) control occurred in 72% with abnormal RVR analysis and 66% of the 121 patients without RVR data (p > 0.1). We conclude that the very low negative predictive value significantly limited the use of RVR analysis in this elderly (mean age 60 years) patient population with a high incidence of mild renal functional impairment (mean serum creatinine 1.4 mg/dl) and bilateral renal artery stenosis (38%). The lack of pre-PTRA renin data did not significantly affect clinical outcome. If RVR data were relied upon as the exclusive selection criterion in patients of this type, many would be prevented from having the benefit of cure or improvement by PTRA.

Local infusion of fibrinolytic agents for acute renal artery thromboembolism: report of ten cases

Management of acute renal artery occlusion remains a therapeutic challenge. We report our experience with 10 cases of acute renal artery occlusion treated primarily by local infusion of fibrinolytic agents. Renal artery occlusion occurred as a result of thrombosis of a stenosed vessel in three cases, from renal artery embolism in two cases, as a complication of percutaneous transluminal angioplasty in four cases, and in association with aortic occlusion in one case. Flank pain was present in all cases and hematuria in four cases. Acute renal failure was seen at the time of presentation in four cases (one case from bilateral occlusion and three cases from an associated nonfunctioning contralateral kidney). Diagnosis was confirmed by renal isotope scanning and arteriography in all cases. All patients were treated by selective infusion of streptokinase or urokinase into the occluded renal arteries. In five cases this was combined with balloon catheter angioplasty. Therapy was initiated within 24 hours from the onset of symptoms in three cases, within 3 days in four cases, within 6 days in two cases, and after 5 weeks in one case. Successful revascularization was initially achieved in 7 of the 10 cases by arteriographic criteria. Rethrombosis occurred in one patient after 3 days and fibrinolytic therapy was repeated successfully. Renal function was restored in one of the four patients presenting with acute renal failure. One complication necessitating resection occurred as a result of fibrinolytic therapy in the form of acute mesenteric embolism with descending colon infarction. No major bleeding complications were encountered and there were no deaths in this group of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term results of angioplasty in 110 patients with renal artery stenosis

Percutaneous transluminal renal angioplasty (PTRA) is generally considered of little benefit in the treatment of ostial renal artery stenosis. This report contains long-term follow-up (> 12 months in all patients; mean follow-up, 38 months) for 110 patients who underwent PTRA for treatment of ostial renal artery stenosis. There was no significant difference in patient benefit related to bilaterality or multiplicity of lesions treated or to renal function before angioplasty (P > .1). Although there was no statistically significant difference in benefit among groups of patients who received treatment, certain trends were apparent. The least benefit occurred in patients with insulin-dependent diabetes and those with symptoms or history of vascular disease in another organ system. Treatment of lesions with proportionately larger balloons did not result in greater benefit. Restenoses were redilated in 16 patients for whom initial treatment failed. Eleven of these were ostial restenoses. The ostial stenosis in one patient was redilated a second time. At the end of follow-up, primary, secondary, and tertiary clinical benefits were 48%, 57%, and 58%, respectively. This was not statistically different (P = .14) from a control group of 94 patients with nonostial stenoses who had 68% long-term benefit. The authors conclude that ostial renal artery stenosis is not a contraindication to PTRA, and balloon angioplasty can play an important role in blood pressure control in this patient population.

Japan's Golden Plan for the elderly

One of the most industrialized nations in the world, Japan has an increasing number of workers reaching retirement age. Faced with tremendous health care costs for its elderly, Japan has proposed a 10-year plan to lessen costs and put health care back into the community.

Nonoperative management of visceral aneurysms and pseudoaneurysms

During the period from 1975 to 1991, 41 patients with 60 visceral artery aneurysms were treated at the Affiliated Hospitals of Emory University. The total included 13 patients in whom 16 aneurysms were treated primarily by transarterial embolization. There were seven hepatic artery aneurysms, three splenic artery aneurysms, three gastroduodenal artery aneurysms, two left gastric artery aneurysms, and one right gastroepiploic artery aneurysm. Average age of these patients was 50 years; there were eight males and five females. Seven patients presented with gastrointestinal bleeding, and two patients presented with abdominal pain. In four patients, the aneurysm was an incidental finding. Etiology of the true or false aneurysms consisted of pancreatitis in two patients, trauma in three patients, connective tissue disease in one, and was unknown in the remainder. Embolization was performed in seven cases with Gianturco coils and Gelfoam, with coils alone in four, with Gelfoam alone in four, and with detachable balloons in one instance. Complete occlusion was achieved initially in 13 cases. Recanalization occurred in two patients over a mean follow-up period of 8.6 months, requiring re-embolization in one patient, whereas the other patient was managed expectantly. In three cases, embolization was unsuccessful: two cases required surgical correction, and one case was managed expectantly. Only one complication was related to the embolization procedure, which was a common hepatic arterial dissection that proceeded to the formation of a false aneurysm. Embolization as the primary treatment modality for visceral artery aneurysms should be considered in patients with the following diagnoses: pseudoaneurysms associated with pancreatitis, intrahepatic aneurysms, most splenic artery aneurysms, and gastric, gastroduodenal, and gastroepiploic aneurysms. The procedure has a low risk and may obviate a difficult surgical procedure, but it does not preclude surgical intervention should the need arise.

Different roles for two enhancer domains in the organ- and age-specific pattern of polyomavirus replication in the mouse

Viral replication in mice infected with murine polyomavirus strains with novel enhancer rearrangements was analyzed by direct in situ hybridization of whole mouse sections and by hybridization of nucleic acids extracted from a specific set of organs. The enhancer rearrangements included a deletion of the B domain as well as duplications within the A domain. Comparisons between enhancer variants demonstrate that the B domain plays an important role in replication in most organs, in particular in the kidney, at the neonatal stage (days 0 to 7 postbirth). In contrast, the B domain is not required in those organs which can sustain replication in the adult, i.e. mammary gland, skin, and bone (class I organs [J. J. Wirth, A. Amalfitano, R. Gross, M. B. A. Oldstone, and M. M. Fluck, J. Virol. 66:3278-3286, 1992]). Altogether, the results suggest that the B and A domains mediate very different functions in infection of mice, controlling the acute and persistent phases of infection, respectively. A model of mouse infection based on the crucial role of differentially expressed host transcription factors is presented.

Peripheral transcatheter embolization with platinum microcoils

Embolotherapy with platinum microcoils delivered through the Tracker-18 microcatheter (Target Therapeutics, San Jose, Calif) was performed in 16 patients when peripheral superselective catheterization with standard angiographic catheters was not possible. The Tracker-18 catheter could be directed distally into small peripheral vessels for delivery of the microcoils. These microcoils, with attached fiber strands, resulted in vascular occlusion within a few minutes in all cases. Embolotherapy was technically successful in all patients. The procedures were clinically successful in 15 of 16 patients (94%), and no complications were encountered. Embolization with platinum microcoils through the Tracker-18 catheter is useful when standard methods of embolization are not possible.

Arterial injuries associated with complete dislocation of the knee

To determine the frequency and type of arterial injuries associated with complete dislocation of the knee and to correlate the findings at physical examination with those at arteriography, a computerized search for patients with a diagnosis of dislocation of the knee at discharge from an urban trauma hospital was performed. Nineteen patients with complete dislocation of the knee were found. Arterial injuries were seen in six patients (32%). Four of the 19 patients had no pedal pulse at physical examination. In three of these four patients, occlusion of the popliteal artery was seen on arteriograms. The fourth patient had occlusion of an anomalous anterior tibial artery and a compartmental syndrome. Two of the 15 other patients with pedal pulses (13%) had nonoccluding intimal defects of the popliteal artery; these two patients did well without surgery. It is concluded that abnormal peripheral pulses associated with complete knee dislocation are highly predictive of major arterial injury. If peripheral pulses are normal, a low but definite frequency of arterial damage exists.