Abstract P4-20-07: Research biopsies in oncology-patient willingness, perceptions, understanding, and experience: An integrative review

Research Biopsies in Oncology – Patient Willingness, Perceptions, Understanding, and Experience: An Integrative Review.

Background

Tumors are classified into subsets based on molecular alterations to select personalized therapies, and research biopsies are essential to advance personalized medicine. However, research biopsies can be associated with complications, results might not directly benefit the patient particularly on-treatment biopsies obtained for evaluation of pharmacodynamics effect, and mandatory requirement can impact patient enrollment in clinical trials. Understanding patient perceptions and experiences surrounding research biopsies may highlight areas for improvement and could expand participation in clinical trials.

Objectives

The purpose of this integrative review explores and summarizes the current literature on oncology patient perceptions, willingness and experience of research biopsies evaluates data to determine potential implications for practice improvement, patient experience, and clinical trial participation.

Methods

Articles from January 2010-February 2016 were retrieved via a systematic search restricted to English of MEDLINE/Ovid. Search terms included breast cancer, cancer, research, biopsy, perceptions and attitudes. Inclusion criteria were studies that included patients with cancer and had information on patient willingness, perceptions, understanding, attitudes, and/or experience around research biopsies. Abstracts were independently reviewed for inclusion by two authors. For each selected manuscript, the following information was abstracted: primary author, sample and setting, results, conclusion, and assessment of strength of evidence level and quality using John Hopkins Nursing Evidence Based Practice (JHNEBP) Rating Scales.

Results

The search resulted in 175 unique studies. 17 abstracts were selected for full manuscript review. From these, 8 were excluded for not meeting inclusion criteria. The 9 selected studies ranged in sample size from 10-362 and all articles were rated IIIA-B evidence level. The majority of studies (66.7%) focused on breast cancer patients. Studies exploring patient willingness to undergo research biopsies (N=8) revealed variability in patient willingness to undergo research biopsies and identified research biopsies identified as a potential barrier to clinical trial participation. Studies exploring patient understanding of the risks and benefits of research biopsies (N=3) revealed overall poor understanding among patients. One study explored anxiety surrounding the research biopsy procedure, suggesting significant anticipatory anxiety is a significant concern. Issues surrounding informed consent were raised in several studies.

Conclusions

Research biopsies can be associated with significant anxiety, potentially impact enrollment in clinical trials, and consequently there is a need for development of strategies to improve patient experience and education. While a separate consent for research biopsies may be onerous, tailored educational materials, focus groups, as well as development of alternate strategies such as liquid biopsies, are essential to ensuring advancement in cancer care and outcomes.

Key Words: cancer, research, biopsy, perceptions, attitudes.

Citation Format: Abraham E, Spring L, D'Alleva J, Malvarosa G, Tripp E, Post K, Bardia A, Habin K. Research biopsies in oncology-patient willingness, perceptions, understanding, and experience: An integrative review [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-20-07.

Chemical model for short-term induction in quaking aspen (Populus tremuloides) foliage against herbivores

Simulated large aspen tortrix (Choristoneura conflictana) herbivory of quaking aspen (Populus tremuloides) induces significant increases in concentrations of two phenol glycosides, salicortin and tremulacin, in leaves within 24 hr. Crushing of leaf tissue, as must occur when aspen leaves are eaten by chewing insects such as the large aspen tortrix, results in conversion of salicortin and tremulacin to 6-hydroxy-2-cyclohexenone (6-HCH). Salicortin, tremulacin, 6-HCH, and its degradation product, catechol, are all toxic to the large aspen tortrix when fed on an artificial diet. These damage-induced chemical changes provide a plausible mechanism for short-term resistance induced in aspen leaves by insect herbivory.

Immediate reversible rehabilitation of the paralyzed eyelid

Skull base surgeons are frequently required to operate in close proximity to the facial nerve. At times, a skull base tumor is resected with the facial nerve grossly infact, only to have the patient awaken with a unilateral facial paresis or paralysis. In the selected cases where the surgeon is certain that the facial nerve has been left intact and return of function is expected, methods are needed to ameliorate the temporary paresis or paralysis of the eyelids. In our institution, eyelid closure has been achieved by placement of a gold weight in the upper eyelid. These weights were placed with the knowledge that they could be removed once facial nerve function returned. We report on 11 such patients who had gold weights placed within 3 weeks of their original intracranial or skull base procedure. All patients were discharged with adequate eyelid closure. Three patients later required lower lid surgery for poor tone or persistence of paralysis. Our experience is reviewed and our recommendations concerning the management of temporary facial paralysis of the eyelids is presented.

Neurotoxicity but not infectivity of prion proteins can be induced reversibly in vitro

Prion diseases include Creutzfeldt-Jakob disease in humans, scrapie in sheep and bovine spongiform encephalopathy. The hallmark of prion diseases is the accumulation of an abnormal isoform (PrP(Sc)) of the cellular prion protein accompanied by neuronal cell death and astroglial proliferation. To characterize the correlation between PrP secondary and quarternary structure and their biological effects we assayed soluble and aggregated forms of PrP 27-30, the N-terminal truncated form of PrP(Sc), as well as the corresponding recombinant PrP(90-231) for their neurotoxicity and infectivity. PrP was kept soluble in 0.2% SDS and subsequently re-aggregated either by diluting the SDS or by adding acetonitril. The neurotoxicity of the re-aggregated states were comparable to that of prion rods (PrP 27-30) whereas the soluble forms had no neurotoxic effects. The solubilized PrP 27-30 showed no significant infection upon re-aggregation as determined by bioassays in Syrian golden hamsters. The recombinant PrP did not exhibit infectivity in any state.

Structural intermediates in the putative pathway from the cellular prion protein to the pathogenic form

The conversion of the alpha-helical, protease sensitive and noninfectious form of the prion protein (PrP(C)) into an insoluble, protease resistant, predominantly beta-sheeted and infectious form (PrP(Sc)) is the fundamental event in prion formation. In the present work, two soluble and stable intermediate structural states are newly identified for recombinant Syrian hamster PrP(90-231) (recPrP), a dimeric alpha-helical state and a tetra- or oligomeric, beta-sheet rich state. In 0.2% SDS at room temperature, recPrP is soluble and exhibits alpha-helical and random coil secondary structure as determined by circular dichroism. Reduction of the SDS concentration to 0.06% leads first to a small increase in alpha-helical content, whereas further dilution to 0.02% results in the aquisition of beta-sheet structure. The reversible transition curve is sigmoidal within a narrow range of SDS concentrations (0.04 to 0.02%). Size exclusion chromatography and chemical crosslinking revealed that the alpha-helical form is dimeric, while the beta-sheet rich form is tetra- or oligomeric. Both the alpha-helical and beta-sheet rich intermediates are soluble and stable. Thus, they should be accessible to further structural and mechanistic studies. At 0.01% SDS, the oligomeric intermediates aggregated into large, insoluble structures as observed by fluorescence correlation spectroscopy. Our results are discussed with respect to the mechanism of PrP(Sc) formation and the propagation of prions.

Prevention of cerebrospinal fluid rhinorrhea in neurotologic surgery

OBJECTIVE

To determine the efficacy and safety of quick-setting hydroxyapatite cement in eliminating cerebrospinal fluid (CSF) rhinorrhea following neurotologic surgery.

STUDY DESIGN

A prospective study of 40 consecutive patients undergoing neurotologic surgery in whom the dura was opened.

SETTING

All patients were treated as hospital inpatients at a tertiary referral center.

PATIENTS

25 men and 15 women between the ages of 20 and 72 years (mean age 51 years) underwent neurotologic surgery at the parent institution.

INTERVENTION

Various neurotologic procedures were performed for the resection of 25 acoustic tumors, 5 meningiomas, 3 glomus tumors, 2 vestibular nerve sections, 2 chordomas, 1 epidermoid tumor, and 1 meningoencephelocele, and for 2 patients referred to our institution with known CSF leaks following acoustic tumor surgery. A new form of quick-setting hydroxyapatite cement, which that hardens within 3 to 5 minutes was used to seal the air cell tracts of the temporal bone in all cases.

MAIN OUTCOME MEASURE

The presence of CSF rhinorrhea postoperatively.

RESULTS

CSF rhinorrhea occurred in 2 patients following acoustic tumor surgery, the first through an occult air cell tract at the margin of the drilled internal auditory canal, and the second via an oval window fistula 1 month after a translabyrinthine approach.

CONCLUSIONS

This form of hydroxyapatite cement appears safe, reliable, effective, and economical for the prevention of CSF rhinorrhea following neurotologic surgery. CSF rhinorrhea cannot be eliminated unless our ability to identify all potential air cell tract communications improves.

Fly larvae and pupae as vectors for scrapie

We analysed experimental transmissibility of the scrapie agent by natural vectors. A fly, Sacrophaga carnaria, fed with brains of scrapie-infected hamsters in different developmental stages caused scrapie in hamsters after they ate fly extracts.

'Bin bag' study: a survey of the research requests received by general practitioners and the primary health care team

General practitioners receive a large and increasing number of unsolicited requests to participate in research. This study describes the volume and nature of research requests received by 18 primary care teams in a three-month period. On average, each practice receives 16 to 24 research requests each year. The most frequent request is to complete a questionnaire (32%). Only one-fifth of studies originate from academic or service general practice. Remuneration for participating in a study was only offered for 15% of studies. Although general practice teams feel swamped by research requests, this sensation may be exaggerated by invitations to participate in non-scientific surveys as well as true research projects. Practice teams would welcome help in distinguishing quality research proposals from the remainder.

Rapid acquisition of beta-sheet structure in the prion protein prior to multimer formation

The N-terminally truncated form of the prion protein, PrP 27-30, and the corresponding recombinant protein, rPrP, were solubilized in 0.2% SDS, and the transitions induced by changing the conditions from 0.2% SDS to physiological conditions, i.e. removing SDS, were characterized with respect to solubility, resistance to proteolysis, secondary structure and multimerization. Circular dichroism, electron microscopy and fluorescence correlation spectroscopy were used to study the structural transitions of PrP. Within one minute the alpha-helical structure of PrP was transformed into one that was enriched in beta-sheets and consisted mainly of dimers. Larger oligomers were found after 20 minutes and larger multimers exhibiting resistance to proteolysis were found after several hours. It was concluded that the monomeric alpha-helical conformation was stable in SDS or when attached to the membrane; however, the state of lowest free energy in aqueous solution at neutral pH seems to be the multimeric, beta-sheet enriched conformation.

Idiopathic, asymptomatic thrombocytopenia in Cavalier King Charles spaniels: 11 cases (1983-1993)

The medical records of 11 Cavalier King Charles spaniels with idiopathic, asymptomatic thrombocytopenia and large-to-giant platelets were identified from a 10-year retrospective search using the Veterinary Medical Data Base at Purdue University. Eight of the dogs had been treated with various immunosuppressive drugs. Six of the treated dogs remained thrombocytopenic, one was not reevaluated, and one developed a normal platelet count. The underlying etiology of idiopathic, asymptomatic thrombocytopenia in Cavalier King Charles spaniels has not been identified, but this condition could represent a congenital macrothrombocytopenic disorder.

[Direct radiographic magnification mammography with a new microfocus tube. Experimental studies of resolution and radiation exposure]

A recently developed X-ray unit for mammography using microfocal (spot size 0.12-0.05 mm) direct magnification radiography will soon be introduced into clinical practice. Unit arrangement and tube construction have been demonstrated. Mean surface dose was measured using PMMA-phantoms. A dose reduction of up to 50% was obtained in 1.7-fold magnification mammography (full sized views) compared with conventional techniques. The image quality was almost equivalent. However, in comparison with 1.7-fold magnification mammography, a comparable dose range for 4-fold magnifications with the microfocus system was measured with a substantial gain in spatial resolution. These findings satisfy the demands of a modern mammographic unit.

Degree of carotid artery stenosis. Comparison of selective and non-selective angiographic findings with surgical specimens

OBJECTIVE

To compare the degree of vessel narrowing seen on selective and non-selective carotid artery catheter angiograms using criteria set by NASCET and ECST with the results obtained from corresponding surgical specimens.

SUBJECTS

In 40 preoperative angiograms (20 non-selective, 20 selective) the 'distal' degree of internal carotid artery (ICA) stenosis according to NASCET criteria and the 'local' degree of stenosis according to ECST criteria was assessed. These data were compared with the 'distal' and 'local' degree of ICA stenosis obtained by measuring the specimens and the diameter of the distal ICA intraoperatively.

RESULTS

The median 'local' degree of stenosis was 86.5% in the specimen and 83.5% in the selective angiograms (difference not significant). In non-selective angiography the median 'local' degree of stenosis was 77.5% compared to 84% in the corresponding specimens (P < 0.01). The median 'distal' degree of stenosis in selective angiography was 76.5 versus 75.5% in the specimens (n.s.). The median 'distal' degree of non-selective angiography was 67% compared to 77.5% in the corresponding specimens (P = 0.02). The trend to underestimate high grade stenosis (above 90%) was more pronounced in non-selective than in selective angiography. Medium grade stenosis (60-80%) was slightly overestimated in selective angiography.

CONCLUSION

Selective angiography is more accurate in determining the 'true' degree of stenosis in internal carotid artery disease, taking into account a slight overestimation of medium grade stenosis. High grade stenosis is underestimated in both selective and non-selective angiography. These observations extend to both the ECST and NASCET criteria of measuring the degree of stenosis, which differ by about 10%.

[Asymptomatic aneurysm of the ileocolic artery]

Visceral aneurysms are rare and account for only 5% of all abdominal aneurysms. Most often they cause no symptoms and are therefore incidental findings. Doppler ultrasonography is the diagnostic method of choice. Therapeutic procedures can be performed either surgically of by interventional therapeutic techniques. This article presents a patient case with an ileocolic artery aneurysm.

[The accuracy of angiography and CT angiography of the carotid bifurcation compared to macro-morphological correlation]

PURPOSE

To compare the degree of carotid artery stenosis in angiography and CT angiography with the degree of stenosis measured in an intact eversion endarterectomy specimen.

METHODS

Preoperative angiograms (intraarterial DSA, 512 x 512 matrix) and CT-angiograms (24 sec spiral scan, slice thickness 2 mm, pitch 1.5) were taken in 12 patients with symptomatic carotid stenosis. Evaluation of the degree of stenosis was performed according to the NASCET ("distal" degree) and ECST ("local" degree) methods. These data were compared with measurements of the surgical specimens.

RESULTS

The median "local" degree of stenosis in angiograms was 81.5% (range: 70-99%), in CT angiograms 83% (59-94%) and in specimens 85.5% (65-96%). The "distal" degree of stenosis was 79% (50-99%) in angiograms, 85.5% (55-99%) in CT angiograms and 81% (52-95%) in specimens. CT angiography slightly overestimated the degree of stenosis compared with the specimen, whereas angiography slightly underestimated the true degree of stenosis. However, these differences were not statistically significant.

CONCLUSION

CT angiography is able to predict the degree of internal carotid stenosis when compared with an intact surgical specimen. It is as accurate as the "gold standard" of invasive angiography.

Disruption of prion rods generates 10-nm spherical particles having high alpha-helical content and lacking scrapie infectivity

An abnormal isoform of the prion protein (PrP) designated PrPSc is the major, or possibly the only, component of infectious prions. Structural studies of PrPSc have been impeded by its lack of solubility under conditions in which infectivity is retained. Among the many detergents examined, only treatment with the ionic detergent sodium dodecyl sulfate (SDS) or Sarkosyl followed by sonication dispersed prion rods which are composed of PrP 27-30, an N-terminally truncated form of PrPSc. After ultracentrifugation at 100,000 x g for 1 h, approximately 30% of the PrP 27-30 and scrapie infectivity were found in the supernatant, which was fractionated by sedimentation through 5 to 20% sucrose gradients. Near the top of the gradient, spherical particles with an observed sedimentation coefficient of approximately 6S, approximately 10 mm in diameter and composed of four to six PrP 27-30 molecules, were found. The spheres could be digested with proteinase K and exhibited little, if any, scrapie infectivity. When the prion rods were disrupted in SDS and the entire sample was fractionated by sucrose gradient centrifugation, a lipid-rich fraction at the meniscus composed of fragments of rods and heterogeneous particles containing high levels of prion infectivity was found. Fractions adjacent to the meniscus also contained spherical particles. Circular dichroism of the spheres revealed 60% alpha-helical content; addition of 25% acetonitrile induced aggregates high in beta sheet but remaining devoid of infectivity. Although the highly purified spherical oligomers of PrP 27-30 lack infectivity, they may provide an excellent substrate for determining conditions of renaturation under which prion particles regain infectivity.

Detection of sperm cells in the canine vagina

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Defects in primer-template binding, processive DNA synthesis, and RNase H activity associated with chimeric reverse transcriptases having the murine leukemia virus polymerase domain joined to Escherichia coli RNase H

The RNase H domain of murine leukemia virus (MuLV) reverse transcriptase (RT) was replaced with Escherichia coli RNase H, and the effect on RNase H activity and processive DNA synthesis was studied, using RNA-DNA hybrids containing sequences from the MuLV polypurine tract (PPT). Two chimeric RTs, having the entire polymerase domain or all but the last 19 amino acids, were expressed. In both cases, these RTs made multiple cuts in PPT-containing substrates, whereas wild-type cleavages occurred primarily at sites consistent with the distance between the polymerase and RNase H active sites. Primer extension assays performed with the chimeric RTs, an RNase H-minus RT, and wild-type showed that the presence of a wild-type viral RNase H domain facilitates processive DNA synthesis. When wild-type RT was bound to primer-template, two retarded bands could be detected in band-shift assays. In the absence of primer extension, a high proportion of enzyme-bound primer-template was associated with the faster-migrating band, whereas with DNA synthesis, more of the bound radioactivity was in the super-shifted complex. This suggests that the super-shifted complex contains the active form of RT. The mutant RTs were deficient in formation of this complex, but the chimeric RTs were somewhat less defective than the RNase H-minus mutant. Our results demonstrate that in the wild-type enzyme, the RNase H domain is required to stabilize the interaction between RT and primer-template.

An unusual case of hematuria in a Welsh corgi

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Effects of antisense DNA on POMC mRNA and ACTH levels in cultured human corticotroph adenoma cells

Antisense oligonucleotides have been investigated in recent years as potential new therapeutic agents because of their ability to shut off gene expression. Antisense DNA and RNA oligomers can bind specifically to mRNA preventing protein translation. We have studied the ability of an antisense POMC oligomer to reduce the expression of POMC in human ACTH-secreting pituitary adenoma cells cultured from 2 uncommon ACTH-secreting macroadenomas. In separate experiments, tumor tissue was enzymatically dispersed, cultured for 4 days, and treated with and without an antisense POMC oligonucleotide for 18 hours. In addition, cells from one tumor were treated with dexamethasone and cells from the other tumor were treated with an unrelated oligomer as controls. RNA was prepared from cultured cells and POMC mRNA was quantitated in a RNase protection assay using a human POMC RNA probe. ACTH in the media was quantitated by RIA. Tumor cells responded to 250 nmol/L dexamethasone with diminished POMC mRNA and ACTH levels 18 hours after treatment (decreased by 28% and 67% of control respectively). In both tumors, a POMC antisense oligomer at a concentration of 50 mumol/L lowered POMC mRNA levels and detectable ACTH levels in the media 18 hours after treatment, with mRNA levels decreased by 76% and 62% of control and ACTH levels decreased by 58% and 48% of control. Conversely, tumor cells treated with an unrelated oligomer at a 50 mumol/L concentration showed minimal effect on POMC mRNA and ACTH levels 18 hours after treatment (decreased by 2.3% and 1.5% of control respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

[Stent angioplasty of the intrarenal aorta and aortic bifurcation. Clinical and angiographical results of a prospective study]

PURPOSE

The study was carried out to evaluate clinical and technical success, early and late complications and patency rates after stent angioplasty of atherosclerotic stenoses and occlusions of the infrarenal abdominal aorta and aortic bifurcation.

PATIENTS AND METHODS

This was a prospective study in 20 consecutive patients treated by implantation of balloon-expandable stents. All patients were followed-up after 6 and 12 months and at yearly intervals thereafter by physical examination, Doppler sonography and angiography.

RESULTS

Nineteen of 20 patients had clinical and technical success. In two patients clinically relevant complications occurred. During a mean observation time of 19 months (range 3-51 months) restenosis occurred in one stent after 15 months and was successfully treated by balloon angioplasty. Two patients became symptomatic again due to new atherosclerotic disease.

CONCLUSIONS

Percutaneous stent angioplasty of the infrarenal aorta and aortic bifurcation yields high immediate and mid-term success rates with primary patency of 90% and secondary patency of 95%. These results are slightly better than those with balloon angioplasty, but the limited number of patients in our and others' studies does not yet justify general recommendations.

Management of the eye after iatrogenic facial paralysis

The aesthetic and functional morbidity associated with facial palsy is significant. Fortunately, corneal exposure and ulceration with the potential for the loss of visual acuity can be minimized by eyelid procedures such as gold weight implantation and horizontal eyelid shortening. Although primarily designed for restoration of eyelid function, these procedures also improve ocular cosmesis. However, uncertainty remains regarding the indications for eyelid surgery: When should surgery be performed, in whom, and which procedure(s)? On the basis of our series of 60 patients evaluated for facial paralysis, guidelines for the management of the paralyzed eyelids after iatrogenic injury to the facial nerve are proposed.

c-myc, c-fos, and c-myb gene expression in human pituitary adenomas

The possible roles of certain oncogenes in the development of pituitary tumors has not been investigated. We have examined the expression of c-myc, c-fos, and c-myb in a number of human pituitary tumors by ribonuclease protection assays, as these oncogenes have been implicated to have roles in the pathogenesis of other human tumors (12, 13, 15, 16). In several tumors examined (9 of 30) c-myc was expressed at levels 4-9 times greater than the level detected in normal postmortem pituitary. Although a larger percentage of negative immunohistochemical-staining tumors overexpressed c-myc, c-myc over-expression was not limited to this group of tumors. c-Fos was overexpressed in 1 of 30 tumors examined at a level 5.8-fold higher than that detected in normal postmortem pituitary. This tumor stained positive for ACTH by immunohistochemistry and was considered highly aggressive, demonstrating invasion beyond the sella turcica; however, when other ACTH-staining and invasive pituitary tumors were examined, no abnormality in the expression of c-fos was detected. In 30 tumors, c-myb was expressed at approximately the same level as that detected in normal postmortem pituitary. We conclude that c-myc is overexpressed in a subgroup of pituitary tumors and that this overexpression occurs broadly among the different groups of immunohistochemical-staining tumors. c-Fos overexpression appears to be much less common in pituitary tumors and does not necessarily correlate with the ability of the tumor to become invasive. c-Myb does not appear to have a role in the pathogenesis of pituitary tumors.

Regiospecific reduction of polycyclic aromatic quinones by rabbit liver dihydrodiol dehydrogenases

Dihydrodiol dehydrogenase (DDH) isoenzymes were purified from rabbit liver (Klein et al., Eur. J. Biochem., 205 (1992) 1155), and the major forms CF-1, CF-5 and CM-2 were tested for their substrate specificity with dihydrodiol and quinone metabolites of polycyclic aromatic hydrocarbons. CF-5, which was shown to correspond to aldehyde reductase in rabbit liver, was found to efficiently oxidize aromatic dihydrodiol metabolites (phenanthrene-1,2-dihydrodiol, benz[a]anthracene-3,4-dihydrodiol) while CF-1, corresponding to carbonyl reductase, and CM-2 were much less active. All three enzyme forms were found to reduce polycyclic K-region o-quinones of benz[a]anthracene, chrysene and benzo[a]pyrene. CF-1 was the least active, and CM-2 was the most active form with reaction velocities of > 10 mumol/min.mg protein. Among a range of synthetic quinones tested, benz[a]anthracene-8,9-quinone and benzo[a]pyrene 9,10-quinone were also good substrates for the three enzymes, as well as p-benzoquinone and naphthalene-1,4-quinone. The reduction of polycyclic o-quinones, but not of p-benzoquinone, by enzyme CM-2 was accompanied by the oxidation of large amounts of NADPH and the consumption of molecular oxygen which is indicative of a redox-cycling process. Thus, the formation of catechol metabolites from dihydrodiols and o-quinones may be catalyzed by the same enzymes in rabbit liver, and the reaction rate of the enzymatic reduction is strongly dependent on the structural type of the polycyclic quinone.

Free Tissue Transfer for Skull Base Reconstruction Analysis of Complications and a Classification Scheme for Defining Skull Base Defects

OBJECTIVE

The role of free flaps in skull base reconstruction is discussed in detail. Twenty-six microvascular free tissue transfers performed in 22 patients are reviewed in detail. A classification scheme for skull base defects is presented.

SETTING

Tertiary referral center.

PATIENTS

Twenty-two patients with neoplasms that involve the skull base underwent a combined craniotomy and facial approach for resection. The resultant defects were reconstructed with a variety of microvascular free flaps.

RESULTS

All 22 patients were ultimately successfully reconstructed with a free flap. One patient required a second free flap following ablative surgery for a recurrent tumor. The initial free flaps in three patients were unsuccessful and a second flap was required. The classification scheme was applied to all defects.

CONCLUSIONS

The creation of a functional separation of the intracranial and extracranial cavities can be extremely difficult to accomplish, especially when multiple cavities (nasal, oral, pharyngeal) are violated. Free flaps provide a solution to this problem in select cases. Skull base defects can and should be classified for the purpose of communication, treatment planning, prognosis of reconstruction, and judging therapeutic outcome.

[Dialysis-associated amyloidosis. Part 2: Incidence and site of osseous amyloidosis. Dialysis characteristics and clinical findings]

In a conventional radiographic skeletal survey of 90 hemodialyzed patients, 28% (25 patients) showed renal osteopathy; 27 patients (30%) had periarticular bone cysts and 3 patients (3%) presented radiological evidence of destructive spondylarthropathy. The bone cysts were most commonly identified in the carpal bones and around the hips and shoulders; destructive spondylarthropathy was seen in the cervical and lumbar spine. Whereas characteristic radiographic changes of renal osteodystrophy could already be identified in the 1st year of dialysis, periarticular bone cysts occurred at the earliest after 2 years, most frequently after 5 years of dialysis. Destructive spondylarthropathy was seen after more than 10 years of dialysis. A positive correlation between these bone lesions and secondary hyperparathyreoidism, dialysis membranes or renal diseases was not found.

A large deletion in the connection subdomain of murine leukemia virus reverse transcriptase or replacement of the RNase H domain with Escherichia coli RNase H results in altered polymerase and RNase H activities

The functional relationship between the polymerase and RNase H domains of reverse transcriptase (RT) was investigated by studying the activities of AKR murine leukemia virus (MuLV) enzymes. In addition to the wild type, an RNase H-minus RT missing the entire RNase H domain and two other mutants having abnormal polymerase:RNase H ratios were expressed. These mutants include (i) a chimeric protein in which the MuLV RNase H domain was replaced by the entire Escherichia coli RNase H sequence and (ii) an RT with a 126 amino acid deletion in a region analogous to the "connection" subdomain in the p66 subunit of human immunodeficiency virus type 1 RT (Kohlstaedt, L. A., Wang, J., Friedman, J. M., Rice, P. A., & Steitz, T. A. (1992) Science 256, 1783-1790). With the wild-type RT, the major RNase H cleavage reaction was coordinated with DNA synthesis and occurred at a position corresponding to 15 nucleotides from the 3'-terminus of the DNA primer. Additional cleavages closer to the 5'-end of the RNA were explained in terms of a model relating binding of the RNA.DNA hybrid substrate and enzyme structure. The chimeric RT behaved like E. coli RNase H, exhibited 300-fold higher RNase H activity than wild-type RT, and was limited in its ability to synthesize DNA. Qualitative and quantitative changes in the polymerase and RNase H activities of the deletion mutant were also observed. The RNase H domain appeared to function independently of the polymerase domain, supporting the idea that the proper spatial relationship between the two active centers was disrupted by the mutation. Taken together, our results indicate that alteration of the normal polymerase:RNase H ratio can have profound effects on both polymerase and RNase H cleavage activities, as expected for an enzyme with two interdependent domains.

[Dialysis-associated amyloidosis. Part 1: Biochemistry, clinical aspects, roentgen morphology]

Dialysis-related amyloidosis is characterized clinically by the carpal tunnel syndrome, pain and swelling of joints. These alterations are due to amyloid deposits in the carpal tunnel, in the synovia, ligaments and bones. It has been shown that beta 2m is the major component of this amyloidosis. Serum and urine concentration of beta 2m are markedly elevated in chronic renal failure due to failure of filtration and lack of metabolism by the renal tubular epithelium. beta 2m-derived amyloid is identified by immunohistochemistry using antibodies derived against beta 2m. Radiology shows cyst-like periarticular bone defects, destructive arthropathy and spondylarthropathy.

Effect of oral administration of sulfadiazine and trimethoprim in combination on thyroid function in dogs

The effect of oral administration of sulfadiazine and trimethoprim in combination on serum concentrations of thyroxine (T4), triiodothyronine (T3) and free thyroxine (fT4) and the thyroid hormone response to thyrotropin administration was assessed. Six dogs were administered sulfadiazine (12.5 mg/kg) and trimethoprim (2.5 mg/kg) orally for 28 days; six untreated dogs acted as controls. Serum T4, T3 and fT4 were determined weekly during and for four weeks after treatment. Thyrotropin response tests were performed prior to treatment, after four weeks of treatment and three weeks after stopping treatment. There were no significant differences in mean serum T4, T3 or fT4 concentrations between treated and control groups at any time during the study. Mean concentration of serum T4 over time did not differ significantly from baseline concentration in either group. Significant differences in the mean serum T3 and fT4 concentrations occurred at several time points in treatment and control groups, and were apparently unrelated to treatment. Significant differences in the T4 or T3 response to thyrotropin administration within or between groups were not present. Serum T3 and fT4 concentrations fluctuate in normal dogs. Administration of sulfadiazine and trimethoprim in combination does not affect tests of thyroid function in the dog.

Renal artery aneurysm: surgical indications and results

The clinical course of 23 patients with 28 renal artery aneurysms (RAAs) is reported. The RAAs were recorded over a period of 10 years. Thirty-five per cent of the RAAs (eight of 23 patients) were detected during the investigation of hypertension, whereas 26% (six of 23 patients) were discovered incidentally while imaging atherosclerotic arterial disease in the aorto-iliac region by angiography. Twenty-two aneurysms were treated surgically and primary nephrectomy was necessary in one case. The surgical technique used was excision of the aneurysm with bypass grafting in 13 cases (seven Dacron, five vein, one arterial bypass), a running suture following aneurysm excision in four cases and an end-to-end anastomosis in two cases. The results (for a period of 1-10 years) were excellent in all but three cases: two early graft occlusions (vein interposition) and one late occlusion (Dacron bypass) in the course of a re-operation which had become necessary because of a ruptured aneurysm of the gastro-epiploic artery after 3 months. Three of 23 patients were treated by embolisation of four intraparenchymal aneurysms. The follow-up of a non-treated saccular aneurysm showed a total thrombosis of the aneurysm within 4 years and fixed renal hypertension developed later in this patient. We suggest surgical repair of an RAA regardless of its size and the clinical symptoms, in order to prevent microembolism into the renal parenchyma and to avoid the development of fixed renal hypertension. Intrarenal aneurysms can be treated by embolisation to stop severe haematuria thus preserving the kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Quinone reduction and redox cycling catalysed by purified rat liver dihydrodiol/3 alpha-hydroxysteroid dehydrogenase

A highly active preparation of rat liver dihydrodiol/3 alpha-hydroxysteroid dehydrogenase was obtained using a newly developed, rapid purification scheme involving affinity chromatography on Red Sepharose. Depending on the coenzyme present, the purified enzyme was found to catalyse the oxidation of dihydrodiols and steroids or the reduction of substrates with carbonyl or quinone moieties. Using a wide range of synthetic quinones derived from polycyclic aromatic hydrocarbons (PAHs), we observed a pronounced regioselectivity of the quinone reductase activity. Good substrates were the o-quinones of phenanthrene, benz(a)anthracene, chrysene and benzo(a)pyrene with the quinonoid moiety in the K-region which were reduced at rates of 1-10 mumol/min.mg enzyme. 1,4-Benzoquinone, naphthalene-1,2-quinone and benz(a)anthracene-8,9-quinone were also reduced at high rates. In contrast, alkyl-substituted quinones such as duroquinone and menadione were poor substrates for the enzyme. During the enzymatic reduction of several o-quinones, but not 1,4-benzoquinone, we observed the oxidation of large amounts of NADPH and the consumption of molecular oxygen which is indicative of a redox-cycling process. Thus, the reduction of quinones of PAHs may lead to a facilitated conjugation and excretion of these highly lipophilic compounds, but may also initiate toxic processes due to the formation of reactive oxygen species.

Dihydrodiol dehydrogenase activities of rabbit liver are associated with hydroxysteroid dehydrogenases and aldo-keto reductases

1. Dihydrodiol dehydrogenase activities were investigated in rabbit liver. Using a five-step purification scheme, eight isoenzymes of dihydrodiol dehydrogenase with isoelectric points of 5.55-9.3 and promoter molecular masses of 34-35 kDa were purified to apparent homogeneity and designated CF-1 to CF-6, CM-1 and CM-2. 2. CF-1 and CF-2 had near-neutral isoelectric points of 7.4 and 6.8 and molecular masses of about 125 kDa in the native state. Both enzymes readily accepted NAD+ as well as NADP+ as coenzymes, had relatively low Km values of 0.33 mM and 0.47 mM for benzene dihydrodiol and resembled previously described carbonyl reductases in their substrate specificity towards ketones and quinones. 3. CF-5 and CF-6 had acidic isoelectric points of 5.9 and 5.55 and native molecular masses of approximately 60 kDa. They displayed a strong preference for NADP(H) as coenzyme and had high Km and Vmax with benzene dihydrodiol. Since these enzymes reduced p-nitrobenzaldehyde and glucuronic acid efficiently, they appeared to be closely related to aldehyde reductase. 4. CF-4 had a high 3 alpha-hydroxysteroid dehydrogenase activity for the diagnostic substrate androsterone, a moderate activity for other 3 alpha-hydroxysteroids as well as 17 alpha-hydroxysteroids, and relatively low activities for 3 beta-hydroxysteroids and 17 beta-hydroxysteroids. CF-5 and CM-1 had high 17 beta-hydroxysteroid dehydrogenase activity for the diagnostic substrate 5 alpha-dihydrotestosterone, and low to moderate activities for other 17 beta-hydroxysteroids as well as 3 alpha-hydroxysteroids. 5. The isoenzyme CM-2 had an isoelectric point of 9.3 and was a very active quinone reductase with phenanthrene-9,10-quinone as substrate. It was potently inhibited by phenobarbital. 6. We conclude that the dihydrodiol dehydrogenase activities of rabbit liver are associated with aldehyde and carbonyl reductase and with 3 alpha-hydroxysteroid and 17 beta-hydroxysteroid dehydrogenases.

Measurement of 3-D facial contours for the design of half-face respirators

A portable anthropometric test rig capable of obtaining three-dimensional face shape data was developed and used to obtain information relating to facial shape, stiffness, and variance for a selected subgroup of respirator users in the Australian work force. A respirator seal shape most suited to the sample population was obtained by studying the central portion of the face of all the subjects. The optimum seal shape was established by following the path of minimum variance among all the faces; the method provided information on the shape, dimensions, and stiffness of the optimum seal for a respirator suited to the sample population. The seal surface flexibility required for a comfortable fit was determined by measuring the deflection of the skin caused by an applied pressure and using this information along with face shape variance data. Results indicated that the required flexibility in the seal surface increased toward the lower portion of the face.

Cutaneous lymphangioma in a young dog

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[Renal artery aneurysms]

Between 1980 and 1990, 21 patients with 26 renal artery aneurysms (0.4-16.5 cm in diameter) were diagnosed and treated at the Surgical Center, University of Heidelberg. Surgical reconstructive methods were applied to treat extrarenal and interventional embolization to treat intrarenal aneurysms. The most effective diagnostic method is selective intraarterial angiography. The etiology, age distribution, localization and clinical aspects are discussed. Four bleeding intrarenal aneurysms were embolized with full preservation of renal function (one solitary kidney). After surgical reconstruction of the aneurysmatic vessel, 80% of the hypertensive patients turned normotensive. Follow-up of a nontreated sacciform aneurysm showed total thrombosis within 4 years. In the same period, fixed renal hypertension developed in the patient because of recurrent microembolism in the renal parenchyma. Therefore, we suggest immediate treatment of a renal aneurysm to prevent the development of renal hypertension.

Vaginal hyperplasia in the bitch: Literature review and commentary

We reviewed the incidence, etiology, clinical presentations, diagnosis, treatments and prevention of canine vaginal hyperplasia, and describe a simple surgical technique for its correction as practiced at the Small Animal Clinic, State University of Utrecht, The Netherlands. Many different treatments have been used, and some are novel approaches. In many cases, prevention is accomplished if the bitch is ovariectomized; there is a high incidence of recurrence with medical treatment.

An unusual case of canine vaginal hyperplasia

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[Diagnosis and differential diagnosis of hepatic artery aneurysms]

Four cases of intra- and extrahepatic aneurysms of the hepatic artery are discussed concerning the etiology, symptoms, therapy and complication rate. The diagnostic approach and problems in differential diagnosis are specified. Localization of the aneurysm and especially the relationship of the collateral circulation of the hepatic bed are essential to plan the therapy and are based on angiography. Interventional therapeutic techniques are favored for intrahepatic localization. Reconstructive or ablative surgery is indicated to treat the extrahepatic aneurysm.

Hearing after retrolabyrinthine vestibular neurectomy

Thirty-four patients underwent vestibular neurectomies between September 1984 and January 1989. The first 15 patients operated on through January 1987 (and followed for a minimum of 2 years) were evaluated separately for long-term hearing preservation and freedom from vertigo spells. Audiograms taken at 1 postoperative month revealed no change in the pure tone averages of 25 patients and showed improved hearing of 20 to 30 dB in 5 patients. Two patients sustained losses of 18.5 dB and 21 dB, respectively. The speech discrimination scores remained the same in 17 patients, improved in 9, and were reduced in 6. Audiograms performed 12 to 40 months postoperatively showed preservation of the pure tone averages and speech discrimination scores when compared with the earlier 1-month postoperative audiograms in 73% of the patients. The speech discrimination scores, however, tended to fluctuate with the symptomatic course of each disease. Two patients developed major vertigo spells 1 1/2 years following surgery. Postoperative ice-caloric testing revealed no responses in 25 patients and markedly reduced responses in 6. There were no major complications or facial paralysis. The retrolabyrinthine vestibular neurectomy is an effective way to control vertigo with preservation of hearing and an acceptably low incidence of complications and side effects.

The oxidation of the highly tumorigenic benz[a]anthracene 3,4-dihydrodiol by rat liver dihydrodiol dehydrogenase

Rat liver dihydrodiol dehydrogenase (DDH, EC 1.3.1.20) has been shown to reduce the mutagenicity of benz[a]anthracene (BA) in the bacterial Ames test. BA-3,4-dihydrodiol is a highly mutagenic and tumorigenic metabolite of BA. In order to test the hypothesis that this dihydrodiol may be a substrate of DDH, we established two novel assay systems for the NADP(+)-dependent oxidation of BA-3,4-dihydrodiol by rat liver DDH, an HPLC-based assay procedure and a radiometric assay with specifically labelled [3,4-3H]-BA-3,4-dihydrodiol as substrate. With the HPLC-based assay, the kinetic constants of the enzymatic catalysis were as follows: Km(app) = 21 microM for BA-3,4-dihydrodiol and Vmax = 20.0 nmol/min.mg enzyme. The reaction product was identified by cochromatography, fluorimetry and mass spectroscopy as BA-3,4-catechol, but interconversions between the catechol and the corresponding o-quinone during the analytical procedures were detected. With the radiolabelled substrate, a linear relationship between substrate concentration and reaction velocity was found. The V/K value for labelled substrate was 0.155 ml/min.mg enzyme and a (V/K)H/(V/K)T kinetic isotope effect of 6.7 was observed. The non-labelled substrate acted as a competitive inhibitor of the enzymatic oxidation of tritiated BA-3,4-dihydrodiol with a Ki value of 56.4 microM. The reaction rates determined in this study suggest an important role of DDH activity in the metabolism of BA.

Effect of hypolipidemic compounds on lauric acid hydroxylation and phase II enzymes

Treatment of male Fischer 344 rats with various hypolipidemic drugs of different peroxisome proliferating potency (1-benzylimidazole, acetylsalicylic acid, clofibrate, tiadenol) led to an induction of liver lauric acid hydroxylase, whereas probucol, which is not a peroxisome proliferator, did not induce this enzyme. Activity of bilirubin UDP-glucuronosyltransferase was increased by all the compounds tested. The highest increase was observed after treatment with acetylsalicylic acid (2.3-fold). High correlation (r = 0.953) was observed between the activities of lauric acid hydroxylase and the corresponding activities of cytosolic epoxide hydrolase reported previously. The amount of microsomal epoxide hydrolase was not changed by any of the compounds. Whereas clofibrate and tiadenol decreased glutathione S-transferase activity with 1-chloro-2,4-dinitrobenzene as substrate, 1-benzylimidazole and probucol increased this activity. With 4-hydroxynonenal as a substrate qualitatively the same results were obtained with the exception that probucol did not affect the enzyme activity. When glutathione S-transferase activity was measured with cis-stilbene oxide as substrate only the more than five-fold increase after treatment with 1-benzylimidazole was significantly different from control values. Activity of dihydrodiol dehydrogenase was increased after treatment of rats with 1-benzylimidazole (1.5-fold), whereas application of tiadenol led to a decrease of enzyme activity. Feeding of male guinea pigs with clofibrate did not change the activity of peroxisomal beta-oxidation, cytosolic epoxide hydrolase or lauric acid hydroxylase. However, treatment with tiadenol caused an increase of these activities.